DEGENERATIVE DISCOGENIC SYNDROME
- From Conservative to Fusion Therapies -
International Published Data
GMCD Instructional Course Lectures
Dr. med. Guy M.C. Declerck MD (GMCD)
Medical FRCS-, FRCS Ed Orth-, M Ch Orth-, PhD-studies
Spinal Surgical and Research Fellow, Perth, Western Australia
Spinal Orthopaedic Surgeon and Surgical Instructor
Consultant R&D Innovative & Restorative Spinal Technologies
President International Association of Andullation Technology (IAAT)
Translation: Filip Vanhaecke PhD
Illustrative expertise and page layout: Lennart Benoot, Mincko, Halle, Flanders, Belgium
Review scientific literature: Medical Consulting Advice, Ostend, Flanders, Belgium
Support: International Association of Andullation Therapy (IAAT)
Legal advice: Anthony De Zutter, kornukopia.be
11. Existing treatments are largely empiric.
As already mentioned, as long as the mechanobiology of the degenerating lumbar IVD is not fully understood, CLBP will remain the albatross of industry (Pope).
Right now there’s next to nothing for treating DDS and what there is only addresses the symptoms rather than the cause.
As Richard Deyo already stated in 1991: "The history of medical care for LBP of degenerative discogenic origin — one of the most common causes of morbidity and absenteeism in the industrialised countries — involves serial fashions in diagnosis and therapy.”
The preference of a medically and paramedically trained person for offering a particular conservative or surgical treatment to relieve LBP and leg pain is empirical. Insufficient evidence is available to support whatever kind of a treatment guideline.
Progress in diagnosis and management of degenerative CLBP due to DDS will not be possible until further knowledge of the function and behavior of the spinal components is available in both health and disease (Bayliss).
Compliance with the laws of Nature is one of the most important principles of Hippocratic medicine because Nature still remains the greatest healer of most human diseases, whereas the physician only is its assistant.
Hippocrates warns patients against charlatans and incompetent medically trained practitioners who not only demonstrate treatment methods to impress their audience but also use manoeuvres for harm and not for healing (Marketos). Therefore, the basic starting thought for treating CLBP due to DDS always should be willing to read and trying to understand (because it is not that easy!) the combined effects of biochemistry and biomechanics (= mechanobiology) on the genetically predisposed individual who will develop degenerative changes in his/her aging intervertebral discs. And there are no excuses: the is a huge amount of data in the international scientific literature!
13. It is not a problem of technology.
An old saying explains that ‘a man should learn more from his failures than his successes’. And Apple’s Steve Jobs once orated that the real art is ‘knowing what to leave out, not what to put in’. Why then do certain medical practitioners and companies not learn from the wreckage they caused by performing discectomies and rigid arthrodeses for CLBP due to DDS? Mother Nature does not like it at all. Discectomies accelerate DDS. And what are the consequences when plates and screws are inserted under high tension in the vertebral bones once they become the main structures undergoing osteoporosis?
It certainly is not a problem of technology, and certainly not due to a shortness of innovative ideas respecting the laws of Mother Nature! It’s the longstanding and universal problem of human nature: ‘seeking of financial gains without respecting the normal aging evolution of the spine’ (Pogue).
“Age offers a lot of information to mankind and I would like to think that we will rise to the challenges it presents. But it is vital to remember that information — in the sense of raw data — is not knowledge, that knowledge is not wisdom, and that wisdom is not foresight. But information remains the first essential step to all of these (Clarke).”
14. Some figures regarding ‘spinal expenses’ in Belgium
It is important to determine whether or not each of the vast existing group of non-invasive and invasive treatments related to the DDS is a cost-effective approach for improving the health of the CLBP sufferer (Shvartzman; van der Roer).
The author has no clue if the costs regarding treatments for LBP, published in Belgium in 2006, correspond with a good or excellent outcome for the treated LBP sufferer (Table 14). Based on his local and international experience, he’s very suspicious! For interpretation of the underneath data it remains essential as well to understand that Belgium is the gateway to one of the easiest social security systems in the world!
Spinal cord stimulation
Surgery with stiffening of the spine (arthrodesis)
Surgery without stiffening procedures
Table 14. The costs of different groups of therapies for LBP in 2006 for one of the most easily approachable social security systems in the world.
15. Efficiency of non-invasive treatments for chronic degenerative discogenic low back pain (> 3 months)
Although an extensive amount of published data is available concerning non-invasive conservative treatments, there is no evidence for their continuous efficacy. For CLBP-patients, none of the existing treatment options has a proven efficiency support for relieving pain in the long-term (Deyo).
But just as with any other type of medical or paramedical treatment performed on the human being, it is not at all essential to have a sound scientific proof for its beneficial effect. Pragmatic experience indicates if a therapy may lead to excellent clinical outcomes in benign conditions notwithstanding the criticism of conventional medicine which sometimes cannot offer an answer. It is therefore entirely ethical to achieve pain relief by unscientific or even placebo means.
The behaviours embedded in the different conservative therapeutic rituals are responsible for different degrees of associated placebo effects. Then, the degree of treatment success will depend on the relation between practitioner and chronic LBP sufferer. The placebo effect of showing attention, compassion and of modulating anxiety and expectations influences a more positive clinical outcome (Kaptchuk).
But there is a large difference between acute and chronic LBP. Most episodes of acute LBP are not serious in nature. They typically settle noninvasively with rest, physical therapy, chiropractic adjustments, yoga, acupuncture, pharmaceuticals, or temporarily external bracing. However, CLBP of degenerative discogenic nature does not settle itself when ignored (Hestbaek).
Once a patient has been diagnosed to be a CLBP sufferer with DDS, a bewildering variety of non-invasive conservative treatments can be initiated depending on the background of the chosen therapist (Table 15). All aim at an amelioration of symptoms such as pain. Although widely used by many disciplines, all too often these approaches fail and only a few are known to have only a moderate short-term value in scientific trials. Consequently, the percentage of patients who settles with nonoperative care remains elusive. None of the conservative treatments will cure DDS for ever! Why? It’s simple. None of the treatments aims at the restoration of the structural integrity of the IVD. This simply means that the natural evolution of DDS and its responsible underlying cellular and extracellular matrix degrading mechanisms, unique to the painful IVD, are not understood. Therefore, if a particular approach fails, don’t fail to try another one! Anyway, it doesn’t hurt to try!
Biophysical electrotherapy techniques (ionophoresis, diadynamic, and interferential currents), high frequency sound waves (ultrasound), electromagnetic thermotherapy (infra-red, ultra-violet, Laser), transcutaneous electrical nerve stimulation (TENS) only result in short-term effects. These techniques need repetitive applications and are costly. Continuous or intermittent traction has little effect. Balneotherapy, hydrotherapy, back schools, manipulations, and cognitive-behavioral methods may sometimes have a moderate short-term effect.
Type of treatment
Bed Rest > 7 days
Soft Swedish massage
Exercise & Physical reconditioning
Spinal manipulative therapies
none / adverse effects
none / adverse effects
Non-steroidal anti-inflammatory drugs
conflicting (none vs moderate)
Table 15. A large variety of non-invasive treatments may be offered to the chronic LBP sufferer. None has a long-term efficiency record.
16. Prevention by remaining active and physical reconditioning
Activity does not aggravate the pain!
Activity is well known to maintain and to increase bone and muscle strength, to improve cartilage and intervertebral disc nutrition, and to increase the production of pain-reducing hormones endorphins and endocannabinoids.
It is hugely difficult for a human being to perform the most easiest and painless activities! A lifetime of regular active exercises such as walking and/or running and/or bicycling and/or swimming and/or individualized neuromuscular exercise programs will always remain one of the simplest methods to strengthen the dynamic muscular stabilizers of the low back. Nature decided that human beings could not continue to walk on four legs. Then, they have no choice but to strengthen their back muscles. The more exercises and activities performed, the less pronounced is the pain behaviour. Indeed, physically fit people experience much less LBP attacks and are much more tolerant to pain. For these reasons, a lot of chronic LBP patients cope with the pain themselves and do not necessarily seek medical attention. As chronic degenerative discogenic LBP is a benign condition, there is little difference between those who see a physician or therapist and those who ignore the pain or temporarily rest in expectation of natural resolution.
On the other hand, most therapists do not understand the molecular pathology of the degenerative processes. Rare are those who comprehend the disturbed cytokine biology, cellular dysfunction and altered load responses in the degenerating IVD. Then, it’s quite logical that chronic LBP patients suffer from subsequent uncertainty, insecurity, and fear of pain which lead to disengagement in physical activity and results in physical deconditioning.
Simply, chronic LBP patients should force themselves to gradually recover their daily activities to their normal personal levels. Physical reconditioning is highly effective in suppressing pain. Chronic degenerative discogenic LBP may be terribly painful and temporarily disabling. However, at all times it remains a non-fatal spinal condition which, at autopsy, shows the normal evolving aging and degenerative IVD features.
Bedrest for chronic LBP is not a treatment which will settle the underlying cause. Simply impossible! But LBP can cause such a discomfort that the suffering individual has no choice but to temporarily rest in a horizontal position to alleviate his most acute moments. However, there is no scientific evidence whatsoever that bedrest should exceed more than two days if used at all (Deyo).
Long-term bed rest for this condition leads to increased muscle weakness, demineralisation of bone, decreased fitness, and increased distress. All these factors only will increase pain and incapacity. Rest is harmful, activity isn’t.
However, mechanically unloading the lumbar IVD as much as possible is essential because intradiscal hydrostatic pressure decreases and is the lowest in a horizontal position. None of the astronauts and cosmonauts experiences LBP except if loss of bone occurred (= weightless osteoporosis). But living in zero gravity is not an option for most terrestrials. Therefore, a short time of bedrest may be advocated each time when a patient experiences acute pain or each time when a chronic LBP sufferer experiences a new acute episode of pain. On the other hand but only for a few days, it remains wise to restrict physical exacerbation. Indeed, repeated minor injuries to the endplates and to the annulus prolong inflammatory reactions and enhance the degenerative processes to progress (Cinotti; Latham; Ulrich).
18. Local heat and electrothermal procedures
Temperature change techniques such as the application of local heat have been shown to decrease pain in 60 % of people. Local heat therapy may relieve pain-related muscle spasms as well. But local heat only produces a short-term effect (Melzack).
All kind of existing ‘heating or electrothermal’ procedures (= laser and radiofrequency related techniques) may cause alterations in the collagenous structures of the endplates, the nucleus, and the annulus. However, the aimed thermocoagulative denervation and/or blockade of pain generating nerve fibers only may occur unexpectedly and not intentionally as the different stages in the degenerative processes of the IVD cannot be detected. Although very promising according to the originators, the procedure of intradiscal electrothermal therapy (IDET) only provides modest short-term results but absolutely no long-term clinical effect. Indeed, IDET remains aggressive for the collagens in the IVD as the ‘therapy’ destroys their composition.
Percutaneous electrical nerve stimulation (PENS)
Percutaneous intradiscal radiofrequency
Radiofrequency facet denervation
Radiofrequency lesioning DR ganglion
Radiofrequency posterior anuloplasty
Spinal cord stimulation
None & side effects
19. Massage and Andullation
Massage is a soft tissue manipulation. It is performed manually, using a mechanical device or by acupressure. Massage definitely is superior to no treatment. Massage leads to improvement of the disability and pain but surely cannot heal LBP.
None of all the aforementioned conservative treatments can continuously be performed at home. Huge restrictions and limitations by social security systems, waiting lists for treatment (even in private practice), and a large amount of indirect costs do not allow a chronic LBP sufferer to be treated at any time and whenever he/she wishes.
Andullation, being a combination of infrared (short wave length type A) and sinusoidal vibrations within the physiological human range, functions as a complement to suppress LBP symptoms at home (IAAT).
The desire to take medication, essential or not, is perhaps one of the greatest features which distinguishes man from other animals (Osler). But there must be a reason why patients fail to follow instructions for taking medication. With billions of dollars spent each year to test new drugs and devices, you would think clinical trials would help doctors treating the patient in front of them. You would be wrong! (Couzin-Frankel in Science 2015). In the developed world, adherence to long-term therapies is only 50 % (Sabaté; Traverso). Indeed, a lot of medications don’t provide the expected results and cause a lot of complications necessitating other investigations and other drugs. Well thought business!
All types of medications are used by the majority (+/- 80 %) of patients suffering chronic LBP. But medications only have short-term effects.
Nonsteroidal anti-inflammatory drugs (NSAIDs) on an as-needed basis are commonly used to treat inflammation. NSAIDs also have a role as analgesics.
Worldwide, national clinical guidelines recommend paracetamol as the first choice for prescribed analgesics if an acute LBP attack occurs (Koes). However, paracetamol compared with placebo has shown to have no effect on pain, disability, function, global symptom change, sleep, or quality of life (Williams).
Acetaminophen and opioids do not work over the long term (Brodke).
Muscle relaxants should not be used by patients with chronic LBP. Everybody needs strong muscles!
The use of antidepressants is questionable. The author has never been able to understand how these drugs could interfere in one way or the other with the degenerative processes in the IVD.
Acupuncture’s introduction into American and European health care settings, while welcomed by many patients and providers, has encountered substantial scepticism from medical professionals (Briggs; Chan; Leshner).
Indeed, there still is no universally accepted scientific explanation for acupuncture. However, it remains attractive to believe that the practice of acupunctural type of massage (not the Swedish soft type), which goes back several millennia, stimulates (a) the release of large amounts of adenosine - 5´- triphosphate (ATP) by the peripheral skin keratinocytes (purinergic signalling) and (b) the secretion of pain decreasing morphine derivates - endorphins - in the central nervous system (Briggs; Burnstock; Han; Kong; Takano).
All chronic LBP patients, suffering the signs and symptoms of lumbar IVD degeneration (= degenerative discogenic syndrome or DDS), report a moderate but only short-term beneficial effect in alleviating the pain. And when the interaction between the acupuncturist and the patient is kept to a maximum, the beneficial effects on pain may last up to one year.
A systematic review of effectiveness studies in approximately 18.000 study participants resulted in two clear conclusions. When acupuncture is compared to no acupuncture approximately 50 % of the individuals experience reduction in pain severity. When acupuncture is compared to a sham treatment, a more modest reduction of 20 % in pain reduction is achieved (Briggs; Vickers).
Compared to physical therapy, chiropractic manipulation is more effective for acute episodes of low back pain. However, regular manipulations offer no advantage and show no long-term effect in the chronic LBP patient because symptoms recur more frequently than when exercises are performed.
In postmortem spine specimen, nothing occurs in any particular spinal structure during intense ‘manipulation’ of the lumbar spine. For a lot of spinal surgeons, using a whole range of instruments to surgically ‘manipulate’ the spine de visu with great forces in a completely relaxed patient, it remains an enigma to understand which structures in the spine really can be ‘manipulated’ manually.
However, it is possible (but never proven) that some alterations in discogenic spinal loading do occur and changes in discogenic pressure ensue. Indeed, in the course of lumbar disc degeneration, separations of parts of the cartilaginous endplates, nucleus pulposus or annulus fibrosus may cause high intradiscal pressure spots under normal load. However, it remains a hypothesis that manipulation may ‘unload’ these high pressure spots (Coulter; Hurwitz; Skagren; Torstensen).
23. Physical therapies
If you suffer the degenerative discogenic syndrome (DDS), overdependence on passive modalities should be neglected. But physical therapy, encompasses an infinite number of different active muscle strengthening exercise programs (Williams flexion-based; Mc Kenzie extension-based; Saal’s dynamic muscular stabilization; Butler’s neuromobilisation techniques; combination of flexion and extension exercises; resistance-based exercises; aerobic conditioning; stretching). The practice of these activity programs varies from country to country and only depends on the ‘insights’, ‘experience’ and preference of the executors.
Some physicians deem muscular rehabilitation totally unimportant as these therapeutic exercise programs mostly are standardized in a ’one size fits all’ program. They rarely are individualized even during a postoperative rehabilitation period. Although each active exercise regimen usually results in a better outcome than the intake of medications, there exists no particular activity program decreasing pain in every individual. There exists no consistent finding to suggest which active regimen is the best one. Therefore, all rehabilitation philosophies remain valuable but one should be able to tailor the programs individually. However, the problem remains: on what kind of scientific basis should one proceed?
Unless the chronic LBP patient is educated to continue a long-term self-treatment, all active exercise programs only will show a short-term result. And if LBP sufferers are not able to find out themselves, they can be taught how to function, how to avoid painful activities and how to increase individually selected activities without significantly increasing their pain or causing more injury.
24. Goal of physical exercise programs
Physical therapies using stabilizing exercises aim at stabilizing the spine and decreasing abnormal muscle spasms (Cady; Coxhead; Donelson; Gilbert; Jackson; Mathews; McKenzie; Petersen; Rissanen; van Tulder; Williams). Stabilizing exercises surely must be effective when painful and limited lumbar segmental motion is the consequence of dysfunction of the paraspinal muscle complex (O’Sullivan; McGill).
The functional details of the few muscle groups controlling the normal lumbar sagittal curvature and balance during the erect posture are well known (Table 24). On the other hand, erect posture and motion of the lumbar spine are intimately linked to the locomotory mechanics of the thoracic spine, the pelvis and the hip. Indeed, muscle imbalances exaggerate lumbar lordosis in erect posture.
Muscular efforts will avoid or lessen back and leg pain and improve or maintain the (remaining) range of motion in the aging and degenerating lumbar spine. Sufficient strength and endurance of muscles protect the intervertebral discs, the spinal ligaments, the facet joints and control the movements of the spine.
Note: except for traumatic, oncologic and infectious spinal events, injuries to the degenerating lumbar IVDs nearly always occur as a result of the sitting, standing, or bending posture and during gait. And when a spinal operation is performed and paraspinal muscles injured, stability and balance between adjacent segments are no longer intact.
Concentric (shortening) contraction
Result on lumbar spine
In static standing
In static standing
Secondarily kyphotic force
Lumbar flexion reducing lordosis
During dynamic forward flexion
Controls lumbar lordosis
Deep paraspinal muscle layer
Intersegmental posture alignment
Table 24. Effects of concentric contractions of muscle groups stabilising the lumbar spine
25. Why exercise programs can work.
The main pathophysiologic feature in the degenerative discogenic syndrome is the decreasing hydrostatic pressure inside the degrading lumbar intervertebral disc. But exercises cannot increase the water content in the nucleus pulposus of such discs and therefore cannot normalize the hydrostatic pressure (see Intervertebral disc: Biomechanics).
But can exercises stimulate the production of proteoglycans which are responsible for attracting, binding and maintaining water in the IVD? No, they can’t! When the lumbar IVDs no longer are loaded, as experienced by the astronauts and cosmonauts in space, the IVDs become nearly fully hydrated (Ernst; Lis; UK Beam; Dolan; Mannion).
But can exercises be performed in unloaded conditions? No! As a consequence, hip flexion exercises (= trying to direct the knee towards the chest and vice versa) should be performed when lying on one side (doesn’t matter right or left) as compressive loading of the disc remains minimal (Adams; Lotz; Pezowicz).
Others pretend that exercise programs diminish and minimize compressive and shear stresses on the lumbar IVDs. Really? Can these stresses really be decreased during exercises? In normal non-degenerative IVDs, the posterior annular pressure decreases with flexion and increases with extension. However, when degenerative lumbar IVDs are subjected to hyperextension, there is a paradoxical decrease of pressure as the posterior annulus becomes stress shielded by the neural arch (and the zygoapophyseal facetal joints) redirecting most of the force from the respective IVD (Adams).
And last but not least. The general lack of physical therapy specificity suggests that the main effects of the therapies were induced not through the reversal of physical weaknesses targeted by the corresponding exercise modality, but rather through some "central" effect, perhaps involving an adjustment of perception in relation to pain and disability (Mannion).
26. Back-school, functional restoration and work-hardening programs
As the physical effects of chronic LBP patients suffering the chronic degenerative discogenic syndrome may be complicated by non-physical factors such as stress and anxiety, multidisciplinary intensive rehabilitation programs are recommended rather than the routine ‘physical’ therapies. Therefore, back-school, Functional Restoration and Work-Hardening programs have been tailored for these LBP patients.
The programs combine behavioral training, education, endurance, physical training, and work simulation, leading to behavioral modification and increased function. Although very intensive (up to fifty hours per week) these programs only have a short-term effect (Cohen; Mitchell; Teasell). The programs can restore function and reduce disability. However, the pain will not be cured (Fordyce; Mayer; Turner) because none of these approaches addresses the pain generators directly.
27. Biopsychosocial approaches
Biopsychosocial approaches only offer a support in cases of additional depression and/or significant psychosocial components but are not able to heal the degenerative physical lesions in the three components of the intervertebral disc: nucleus pulposus, annulus fibrosus and endplates. These approaches cannot succeed in neutralising the intradiscal degrading chemical processes.
However, it is well known that preoperative depression in response to the pain disappears following successful surgery (Carragee; Hägg; Hobby; Mannion; Tandon; Trief; Waddell).
28. Orthotic devices
Lumbosacral orthotic devices have very little effect on motion between vertebrae even when a thigh extension is added. These orthoses do not limit the sagittal motion of the lumbar spine and as such do not weaken the postural nor the abdominal muscles. However, lumbar supports are effective only for secondary prevention.
29. What if an degenerated disc herniation occurs and does not resolve?
Protrusion and extrusion of degenerating and degenerated nuclear IVD material into the spinal canal may cause sciatica with radicular symptoms. But disc herniation tissue contains blood vessels. These vessels carry inflammatory cells (macrophages, lymphocytes) which play an important role in the spontaneous resorption process of the herniated IVD material over a period of 12 weeks (Minamide). Because the new vascular ingrowth is induced by its contained fibroblast growth factors, the vessels promote the formation of granulation tissue (Tolonen).
If conservative therapy fails following a period of 10 to 12 weeks, a new MRI-image decides if minimal invasive nucleotomy or discectomy needs to be carried out. However, this type of operative interference always will lead to progression of degeneration which will depend on the amount of the nucleus removed and the degree of damage to the posterior vertebral structures.
Discectomies are far from successful. Approximately 27 % of all operated patients request a second operation within 10 years. Consecutive procedures are often necessary: implantation of a nuclear implant, a total disc prosthesis or even fusions. However, it is not at all evident to predict if these ‘reconstructive’ procedures can reduce LBP.
30. The degenerating lumbar IVD cannot repair itself.
The degenerated lumbar IVD has no capabilities to repair its essential concentration of proteoglycans. Therefore, it cannot restore its essential hydration to optimize the extracellular matrix to withstand the changes in osmotic and hydrostatic pressure. Consequently, the IVD cannot resist the compressive and tension forces.
Still a long way to go for a well-researched innovative and working therapy!
31. Spinal injections: epidurals, ‘facet’ blocks, nerve root blocks etc.
In 1982 it was observed that a temporarily relief from pain in chronic LBP patients could be obtained by injecting local anaesthetics into the IVD. With the idea of offering a diagnostic effect, it was the start of selectively injecting anaesthetics and/or glucocorticoids in or around different spinal structures under fluoroscopic guidance (Brodke). At the same time clinicians started applying a whole range of less invasive strategies to treat LBP disorders. Unfortunately, all these approaches only provide therapeutic effects for a short time. None of these injections directs the cause of the degenerative processes (Table 31). By performing or requesting such injections, the author always explained his spinal patients that he was dealing with ‘wishful medicine’. In Google ‘wishful medicine’ is nicely described: ‘the formation of beliefs and making decisions according to what might be pleasing to imagine instead of by appealing to evidence, rationality, or reality. Then, wishful thinking and practising is a product of resolving conflicts between belief and desire’.
Epidurals (= injections of anaesthetics and/or corticosteroids in the lumbar epidural space) are somewhat more effective when chronic LBP is associated with leg pain due to inflammatory nerve root irritation. Otherwise, nothing more than a short-term effect can be expected. They temporarily work in 50 % of patients but nobody can predict who is willing to take profit.
Therapeutic injections with corticosteroids into or around the zygapophyseal facetal joints, into the sacroiliac joints, or into the IVD are not effective in the long-term for chronic LBP.
Multilevel selective blockade of the median branch of the zygapophyseal ‘facet’ joint and multilevel dorsal radiofrequency ‘facetal’ rhizotomies (= denervation of the ‘facet’ joint) only are short-lasting.
The value of prolotherapy (= injecting a mixture of glucose, phenol, and glycerine into the supraspinous, intraspinous, iliolumbar and iliosacral ligaments) and trigger point injections (= injecting local anaesthetic or saline into irritable locations of the muscles and/or their fascia) has never been established as a solution for chronic LBP.
Epidurals for CLBP without leg pain
none & side effects
Epidurals for CLBP with leg pain
none & side effects
Transforaminal epidural injections
none & side effects
none & side effects
Medial branch facet block
none & side effects
Trigger points injections
Intradiscal steroid instillations
none & side effects
Table 31. The different types of injections in and around spinal structures only have minimal effect.
32. Composite hydrogels
Hydrogels are materials that comprise networks of polymer chains that can absorb or release water as conditions change. But tissue composite gels of nucleus pulposus and annulus fibrosus tissue still are impossible to engineer (Alini; Sato).
In 2015, inspired by articular cartilage, Liu and colleagues developed a synthetic hydrogel containing nanoscale sheets of a titaniumoxide, aligned in planes with their faces parallel to each other. The composite hydrogel possesses anisotropic mechanical properties based on electrostatic repulsion between the negatively charged unilamellar titanate nanosheets embedded within it. The hydrogel is a water-swollen polymer network that exhibits impressive direction-dependent behavior and excellent vibration-damping properties and it is able to undergo cycles of compression and expansion as well as horizontal deformation (Liu; Skov).
However, if such a gel could be developed for treating ‘discogenic’ conditions, the main surgical technical problem remains: how to implant the gel in the degenerated nucleus pulposus? Through an intentionally made opening of the annulus fibrosus which is known to accelerate the degenerative processes? Or should the annulus be avoided by inserting the composite hydrogel through an perpedicular approach? Indeed, exiting technically surgical research!
33. Nucleus pulposus replacement implants
To ideally replace the degenerated nucleus pulposus, an implant should behave biologically and biomechanically like a normal natural nucleus pulposus. But in trying to equal or surpass Mother Nature, engineers first need to understand the mechanobiology of the lumbar intervertebral disc. Hence, a huge amount of challenges need to be overcome.
To obtain the mechanobiologic goals, nuclear replacement implants minimally should:
(a) replace the degenerated nucleus pulposus,
(b) stop the degenerative cascade,
(c) restore and maintain a ‘normal’ IVD height,
(d) mimic the normal function of the IVD between two vertebral bodies,
(e) restore normal and uniform load distribution to avoid excessive endplate wear,
(f) repair the kinematics of the intervertebral motion segment,
(g) uniformly transfer loads across the IVD space,
(h) restore turgor and tension to the annulus fibrosus (AF),
(i) decrease annular bulge,
(j) prevent adjacent segment degeneration,
(k) et cetera …
The author was presented a large choice of ‘replacement’ implants but never applied them. Following the removal of the degenerating or degenerated nucleus pulposus (= nucleotomy) through an incision in the AF (= annulotomy), the created void in the IVD could have been injected with or replaced by silicones, polyurethanes, serum albumin polymers, protein-based polymers, silicone-Dacron composite, hydrogel materials with or without a polyethylene jacket and potentially including polyester fibre mesh, shaped polycarbonate urethane elastomers, spherical stainless steel ball, other metal alloys, polymethylmethacrylate acrylic cement (PMMA), polyetheretherketone (PEEK), pyrolytic carbon, and Zirconia ceramics.
The author was not interested in participating in this type of experimental intradiscal surgery. Till now, the long-term results yet have to show improvement of clinical outcomes.
A lot of concerns remain (Bao; Edeland; Fernström; Hamby; Hou; Korge; Thomas; Urbaniak):
However, the major surgical challenge remains.
The highly organized structure of the annulus fibrosus becomes severely damaged as a result of IVD aging (incomplete in-to-outward radial fissures), IVD degeneration (complete in-to-outward annular ruptures and herniations), and surgical procedures (incisions, punctures) during discectomies. Nature may heal these holes by forming granulation tissue. Unfortunately this tissue is of an inferior quality and continues to tear over and over again causing the degenerative discogenic syndrome (DDS). This situation creates the pathway for extrusion of the nuclear implant. Such an extrusion is equal to a serious degenerative nuclear herniation!
Then, the question ensues: can an appropriate AF sailing method be developed which is capable to keep the nuclear replacement implant in place over a long-time period (Natarajan)? Ongoing annular treatment research concentrates on developing a biological annular tissue resembling the highly oriented organizational structure with the mechanical strength of a healthy annulus. As for 2014, it is already experimentally possible to direct cultured bovine annular cells in a well aligned orientation on micro-grooved membranes. Effectively assessing the sailing effects of such an innovative method on the AF in animals can be performed because the characteristics of animal and human AF are not drastically different.
The other surgical challenge is thinking of another perhaps perpedicular inserting technique avoiding making a unnecessary supplementary hole in the annulus fibrosus.
Indeed! Innovative research for treating the degenerative IVD is highly exciting.
34. Any outcome difference between conservative and surgical treatments?
When conservative treatments of the lumbar degenerative discogenic syndrome fail, surgery would and could be the next option. The main target of spinal surgery remains the degenerated IVD. Spinal surgery involves treatments such as fusion with or without rigid instrumentation, non-fusion techniques like dynamic stabilization, total disc arthroplasty, and implanting interspinous devices.
However, none of the existing operative treatments aims at the neutralisation, stabilisation, repair or replacement of the degenerative and inflammatory intradiscal processes nor even at the restoration of the structural integrity of the IVD. Therefore, they still remain controversial. Certainly because the results of the existing surgeries are far from perfect and not at all comparable to those of the replacement surgeries of the knee and the hip joints.
Moreover, whether or not any of the wide variety of spinal surgical treatments for patients with chronic LBP due to the degenerative discogenic syndrome (without degenerative disc herniation, spondylolisthesis, or spinal stenosis) is more or less effective than the wide variety of non-operative measures, still remains elusive.
In the non-randomised and non-controlled studies, the effectiveness of identical lower lumbar spinal fusions for DDS remains extremely contentious. Extreme variable clinical outcomes are reported during the first 3 to 4 years following whatever type of spinal operation. Excellent to good results vary from 16 % to 95 %. Extreme variations in complication rates (56 % - 100 %) are described as well. There is no proven superiority of one rigid system over the other. Therefore, alleging ‘that spinal fusion is the gold standard for chronic LBP and that its analgesic value is beyond question’, remains very questionable, indeed! Long-term evaluation of at least 4 years of follow-up and preferably of 10 years would confirm this statement.
All existing well performed high-quality level 1 studies only report a modest advantage of surgical fusion compared to non-operative treatment for CLBP with the common and well known degenerative signs on MRI. The advantages of both treatment modalities remain unpredictable and very minimal. High levels of success are uncommon in both treated groups, with an average of 15 % if fusion is performed and only 6 % if a conservative treatment was chosen (Brox; Brox; Fairbank; Fritzell; Gibson; Mirza).
35. Transition from conservative to fusion treatments
Each of the conservative and non-surgical approaches, previously mentioned, can initially be prescribed as treatment for the chronic LBP sufferer with a degenerative discogenic syndrome. However, a lot of patients do not benefit from such managements and start hoping that surgical fusion may finally realise benefits (Brox; Fairbank; Fritzell; Mirza). There is as yet no scientific basis in favour of such a transition of management.
36. How and where did spinal fusion originate?
The concept of spinal fusion as a treatment for pathologic conditions in the spine has been in evolution for more than 100 years. The basic concept of spinal fusion has always been to remove the pathologic process, eliminate painful and abnormal motion, and allow decompression of the neural elements by stabilisation and rigidisation of the affected motion segment(s). The first described technique of spinal fusion consisted of a transplantation of a portion of the tibia into the spine (Albee).
The modern techniques of spinal fusion surgery originate from the time when rigid spinal surgical systems were developed for reducing deformities and stabilizing unstable spinal fractures and dislocations. Indeed, and contrary to the degenerative discogenic syndrome, fractures of the vertebral bodies represent real unstable situations. It took the accomplishments of many foreseeing surgeons to treat spinal cord injured patients operatively with the prospect of living past the period of acute spinal injury with an aligned and stable spine. At least, the injury to the spinal column could be treated. Overtime, the techniques of spinal fusion surgery themselves have improved, providing better reduction of deformity and stabilization. Paul Harrington introduced a system of distraction and compression rods and hooks. Roy-Camille developed the pedicle screws. Kaneda and Zielke started with anterior plates and screws. Cotrel and Dubousset introduced pedicle screws and plates (Harrington; Katznelson; Roy-Camille; Meyer). However, the injury to the spinal cord as well as the organ systems to which it brings innervation, have continued to pose great challenges (Ruschel; Tran).
In the meantime, the surgical concepts for treating unstable spinal conditions were introduced to treat the stable degenerative discogenic syndrome.
37. Is fusion / arthrodesis really the ‘golden standard’ of treatment?
The indications for spinal fusion surgery to treat tuberculosis, spinal deformities (poliomyelitis, scoliosis, kyphosis), cancer, and spinal fractures are straightforward. Although spinal fusion surgery in the painful, primary degenerative discogenic syndrome (DDS) remains controversial, its secondary spondylolisthetic or stenotic consequences mostly are dealt with successively with fusion.
Is it really essential to fuse two vertebral bodies to each other because of the degenerative fissures and tears in the nucleus pulposus and/or the annulus fibrosus and/or the endplates? At this moment there still are no arguments. The only indication for all kind of fusion techniques for a degenerative discogenic condition without a typical clinical picture of degenerative disc herniation, without degenerative listhesis between the vertebrae, and without degenerative spinal stenosis, is the failure of a whole battery of non-invasive conservative therapies. And that’s it!
Is lumbar spinal fusion of vertebrae for DDS a scientifically based decision? Or is it wishful thinking, not knowing what to do because the underlying causes of lumbar IVD degeneration are as yet not fully understood? Or is fusion for DDS simply an invention by the health-care and commercial industries to earn a lot of financial benefits?
An universally accepted ‘golden treatment standard’ for discogenic pain based on the degeneration of the IVD (= degenerative discogenic syndrome or DDS) has never been scientifically established. There simply exists no scientific basis for spinal fusion for this condition. Indeed, the only indication for these interventions remains the failure of a large variety of even very aggressive conservative treatments! If there could be a scientific basis, a spinal surgeon would be able to tell in advance who will benefit and why! However, there are no biological nor biomechanical reasons for telling so.
There exist no known definite clinical indications for choosing a particular invasive technique simply because nobody understands why the impact of the daily loading patterns on the degenerative biochemical processes in the lumbar IVD causes pain in some and not in others. Pain sources are expected to be localized there where radiological ‘abnormalities’ are seen. However, there exists no difference in the radiological pictures between symptomatic and asymptomatic individuals and no difference in the radiological images of all those with normal aging and degenerating lumbar spines. More sensitive diagnostic tools, such as the Clarity scans, need to be developed for humans. Pain still cannot be seen and therefore, the spinal indications as well as the spinal interventions remain pure guessing work. At this moment and for the degenerative discogenic syndrome, the frontiers between science, non-science, and pseudoscience remain minimal.
The huge interdisciplinary differences and preferences in spinal surgical techniques and use of spinal implants vary geographically all over the world. They depend on the surgical education of the surgeon, the country of formation, and, most importantly, the marketing techniques of the different health-care and commercial industries (the author was consultant for two such companies).
Every spinal surgeon in the world can be trained to perfectly perform whatever technically highly demanding anterior and/or posterior and/or anteroposterior spinal surgical procedure at top level universities and thereafter under the further supervision of spinal implant developing companies. However, the use of a particular system remains entirely subjective. The extent of adequately training a spinal surgeon is different in each country. It depends on the ‘philosophies and research insights’ of the leading heads of spinal departments and on the indoctrination by biomechanical industries. Unfortunately, the clinical results of spinal fusions (and disc arthroplasties as well) in the treatment of the primary degenerative processes in the IVD (and not of secondary degenerative spondylolisthesis and spinal stenosis) continue to be disappointing and mediocre.
Is there any hope within the next 10-20 years? As long as the excellent scientific brains behind the innovatively IVD engineered tissues do not succeed in the development of a successful strategy to stabilize, replace or repair the loss of the biochemical and structural integrity of the extracellular matrix in the aging and degenerating lumbar IVDs, millions of chronic LBP sufferers all over the world won’t be treated adequately to get rid of their LBP problems. They have no choice but to ‘accept’ the natural course, or to continue their different conservative managements, or finally to accept proposal of fusing their spines.
38. Fusion: illusion of the ‘gold standard’ procedure
Without any scientific basis, the so-called rigid fixation became what has been termed the "gold standard" for treating the degenerative IVD for the related degenerative discogenic syndrome (DDS). Although fusion is the most invasive and destructive treatment procedure for the IVD, an arthrodesing procedure remains the main reason to augment the intervertebral fusion rate. This is the only reason why it is called ‘the golden approach’. Indeed, instrumented ‘rigid’ spinal fusion is considered the gold standard due to superior fusion outcomes compared to non-instrumented fusion procedures.
Since the beginning of the 20th century, the illusive hope still remains that one day a perfect rigid intervertebral fusion system will be able to relieve the patient forever from his LBP once the culprit - the progressively degenerating IVD - has been removed and the intervertebral motion has been eliminated.
The inherent problems with both the surgical destructive methods and long-term rigidity do not allow a long-term painless situation (Chou; Sénégas). Standard test protocols including in vitro laboratory studies, finite element analyses (FEA), and in vivo clinical evaluations did not succeed in developing a very simple, safe, and biomechanically effective spinal surgical implant taking into account the biomechanical as well as the biochemical causes of the degenerating IVD (Goel; Grauer; Wilke).
In reality, and strangely enough, there is still no consensus on what type of rigid fusion procedure should be advocated. The introduction of pedicle instrumentation in the 1960s, cage devices in the 1990s, and frequent use of circumferential fusion resulted in an increase of successful fusion rate, but failed to improve the overall clinical success rate (Boos; Fischgrund). Indeed with more recent sophisticated methods of assessing clinical success, the so-called ‘excellent’ short-term results of fusion are in the region of 30% (Gibson).
39. ‘The Blind leading the Blind’
Fusion surgery for the degenerative discogenic syndrome reminds me my Flemish ancestor Pieter Brueghel the Elder who painted ‘The Blind Leading the Blind’. In other words: ‘Can a blind man lead a blind man? Will he not fall into a pit?’ Indeed, a student is not above his teacher, but everyone who is fully trained will be like his teacher unless he starts learning from his mistakes.
Is there an explanation for such an evolution? The high-tech spinal surgical gadget industry is far too aggressive in treating such a very simple and benign condition. Except for financial and business reasons, it remains a scientific enigma why the surgical spinal industry continues to take over the rigid fusion techniques for unstable (fractured and/or cancerous) spines in the treatment of a benign and stable degenerative discogenic problem. And for a lot of my spinal surgical colleagues, the enigma remains why “books have led some to learning and others to madness, when they swallow more than they can digest” (Petrarca).
Sometimes I remember the Latin phrase of Petronius: ‘Mundus vult decipi, ergo decipiatur’ or "the world wants to be deceived, so let it be deceived."
40. Rigid procedures – Dynamic systems – Total IVD replacements
The major radiological problem in opting for a particular non-surgical or operative treatment of the degenerative discogenic syndrome (DDS) is the large spectrum of visible lumbar intervertebral (intradiscal, annular and endplates), subchondral and vertebral changes related to the intradiscal degenerative processes (see: ‘Degenerative discogenic syndrome: Screening by radiology, CAT and MRI). In other words, nobody in the whole international spinal scientific world has ever been able to explain which degree of IVD degeneration suits a conservative treatment method, a rigid interbody fusion, a dynamic stabilization, an arthroplasty, or … whatever imaginable therapy.
For one and the same condition, there exist
The use of either a rigid, semi-rigid or dynamic instrumentation remains a matter of spinal training and personal preference of the spinal surgeon. The large variety of the different treatment systems (1) deals with comparable radiologic findings to operate on, (2) has similar theoretical advantages, (3) provides more or less equal reduction of stress shielding, (4) shows equivalent protection or increments of adjacent segment degeneration and avoidance of osteopenic fractures, and (5) results in comparable patient-related outcomes (Korovessis).
Whatever the primary (radiological) indication, it is important not to forget that all these different implants can be and are applied simultaneously or as revision methods to neutralise and prevent each other’s deficiencies. A failing IVD arthroplasty is thought to be resolved by supplementation of a posterior rigid or dynamic system at the previously operated level or at the adjacent level to deal with the evidently occurring functional spinal imbalances, intradiscal, and zygapophyseal facetal degeneration, dictated by the aging processes.
Because of the increasing intellectual simplicity by which ‘scientific information’ is provided by the different companies and their ‘key opinion leaders’ about each of the above mentioned group of treatment facilities, it is not excluded that these surgeries one day will be considered waste-of-time and non-justified approaches for chronic degenerative discogenic LBP. There is no doubt these finally will become footnotes in the history of surgical medicine having cost a huge amount of human suffering and millions of euros and/or dollars to their societies.
41. There is a technological gap between spinal surgery and reparative joint surgery of the extremities.
Practically all of the mobile segments of the appendicular skeleton are entirely or almost monoarticular in nature. Destruction of a single major joint, such as the hip or knee, by degenerative processes tends to impair joint function in an all-or-nothing manner. This explains why non-invasive treatments exhibit only poor efficacy when the degenerative process is advanced.
Beginning in the 1960’s, innovative total joint replacement systems gained prominence, rapidly rendering archaic the techniques of mobilizing resection and fusion, the functional results of which were in no way comparable to those of this new technology. Nowadays a simple but diseased monoarticular hip joint can effectively be replaced by an artificial joint (= total joint arthroplasty) with excellent patient related clinical results lasting 20 years or more.
To date, the technologies available for treating the diseased monoarticular joints in the extremities are hugely more advanced than the corresponding technologies for spinal segments. The reason is simple.
The joints between two vertebrae are complex multi-articular segments and not monoarticular! The lumbar spinal segments, consisting of the cartilaginous intervertebral disc and two synovial zygapophyseal joints, have three axial articulations. They permit segmental rotation and translation respectively around and along the three orthogonal axes (X, Y and Z described by White and Panjabi). This is called the tribiology of the vertebral column.
Compared to the monoarticular joints, the degenerative discogenic destruction of a single intervertebral mobile segment, or even of several segments, does not lead to major functional limitation perceived by the patient. Such an impairment is amply compensated by the compliance of the adjacent intervertebral levels and by the relatively enormous reserve of mobility provided by the hip joints in flexion-extension. This functional compensation of damage to intervertebral segments most likely is the reason why research in the preservation of intervertebral mobility has been delayed.
What is more, application of innovative motion-preserving technologies to reproduce the complex structure and function of the intervertebral units is a challenge well beyond the design of hip replacements, which primarily consist of simple ball-joint structures.
42. Fusion: definition and goals
Spinal fusion is a surgical procedure aiming at the achievement of complete motion arrest at the level of the IVD between two or more adjacent vertebrae.
The primary goal is NOT providing pain relief.
The primary goals of arthrodesing two or more vertebrae in the treatment of lumbar degenerative discogenic syndrome (DDS) (and not in case of a degenerative spondylolisthesis!) yield
(a) removing the degenerated IVD material, and
(b) eliminating the influence of the normal daily loading patterns on that disc level (Mulholland).
There exists no scientific basis for thinking that whatever technique that simply can take away the painful degenerative and inflammatory processes inside the IVD (without spondylolisthesis) and fuse the adjacent vertebrae will cure low back pain. Converting the hyper- or hypomobility phase at IVD level into a very rigid and permanent immobile union may alleviate pain for a short while but NOT at all guarantee a lasting relief of symptoms. On the contrary, spinal fusion often is associated with lengthy recovery and lots of pain and discomfort.
43. Fusion: problem. Willingness to rush ahead?
Spinal plates and screws (and prostheses as well) indicate our willingness to rush ahead and use something new without having an idea what the results are going to be in dealing with a stable situation related to a degenerating lumbar IVD. The non-scientifically based overuse of these modern gadgets is devastating our inner biomechanical spinal system. Indeed, many gaps remain in our understanding of the role of the degenerative discogenic syndrome in human health and disease and … of how to resolve it.
Technology plays an important role in the development of surgical procedures to remedy spinal defects since it provides the tools and equipment which will, hopefully, improve the result of a spinal operative procedure in case of a simple degenerating IVD. Indeed, the provided surgical tools are magnificent and are a joy for the spinal surgeon during the implantation of these gadgets in the human spine. However, it would even be better if all these implants could be compatible with the construction and working principles of the vertebral column. They are not! Since the design plans of the complicated construction, called ‘man’, have as yet never been discovered, the shape and the characteristics of the human vertebral column still need to be explained by exploration and functional reasoning.
Therefore, the data are still insufficient to develop ‘the’ ideal implant.
44. Fusion: big business
The author was consultant of two companies producing ‘plates and screws’. It is booming business for multiple companies. Indeed, the Global Burden of Disease Study 2013 indicates that LBP is the leading cause of YLDs - years lived with disability - all over the world (Vos).
Till today, there is still no ideal fusion technique and fusion gadget universally applied and accepted by every spinal surgeon. Moreover, today’s techniques are only based on hundreds of maximum 2-year follow-up studies and rarely on more than 500 patients.
45. Huge amount of lumbar spinal fusions
Lumbar spinal fusion is a very common procedure. It is increasingly performed for lumbar degenerative discogenic syndrome (DDS).
In the USA a total of 380.305 patients underwent some kind of surgical arthrodesis between 2000 and 2009 (Yoshihara).
46. Bone grafts and pseudarthrosis. A problem?
Autologous cancellous bone-grafting (= using its own bone reservoir) provides all the elements needed to promote a successful fusion. Autografts are still the most efficient method to induce therapeutic bone fusion because they contain an osseous matrix, osteoinductive peptides*, and osteoprogenitor cells. However, the grafts are not always available in sufficient volumes, do not always possess a sufficient number of competent osteoblastic progenitor cells (Muschler), and only a small fraction of the transplanted cells survive (Burwell). Their harvesting may result in considerable morbidity. Pain at the level of the abductor mechanism originating at the posterior aspect of the ilium is well known.
A successful arthrodesis between the adjacent vertebrae is facilitated with placement of bone grafts. The iliac crest is one of the preferred sources of autologous graft material. However, in order to avoid the high frequency of associated pain and complications with the surgical procedure of autologous bone harvesting, intervertebral fusion has and is been tried with cancellous allograft bone chips, cortical allografts, ceramic-based bone grafts, demineralized bone matrix** (DBM) and bone graft substitutes such as calcium sulphate (CaS), β-tricalcium phosphate (TCP), or hydroxyapatite (HA). These materials are then mixed with osteoprogenitor cells aspirated from the iliac crest or perpendicularly form the vertebral bone (Heary; Lane, Mc Lain; Younger).
Initially, the high frequency of pseudarthrosis (= false joint formation) was thought to be the main reason for the mediocre postoperative clinical outcomes. In the hope to achieve a 100 % and extremely rigid intervertebral fusion rate, innovative research still leads to the development of a wide range of several internal spinal implants (clamps, wires, plates, rods, interbody cages, and pedicle screw systems), and of bone morphogenetic proteins (= bone growth factors) to augment or induce the osteoinductive effects of the autologous grafts.
Unfortunately, a solid lumbar spinal fusion still cannot always been achieved. The efficacy of the fixation systems has as yet not been demonstrated in clinical studies because pseudarthrosis still occurs in 10 to 15% of all these procedures. Fixation devices may stress-shield the vertebral bodies and transmit more load through the screw-plate device resulting in the screws to become loose with time (Goel). The use of osteoinductive factors are associated as well with significant clinically problematic complications due to bone overgrowth, graft resorption, vertebral bone resorption, intervertebral implant subsidence, foraminal and central stenosis.
On top of all those difficulties, numerous retrospective follow-up studies fail to substantiate that a solid osseous fusion really is substantially better than when the attempted fusion results in pseudarthrosis.
Indeed, before something innovative is found and works ideally in real time, research is like the procession of Echternach (three steps forward and two steps backwards in order to advance only one step) or even more frustrating … like a succession of funerals.
* osteoinductive graft proteins are materials which stimulate the patient’s own system to form new bone
** demineralised bone matrix is created through acid extraction of the mineralised phase of bone
47. Fusion: huge amount of techniques and devices
Although the scientific evidence for their use is non-existent (Mulholland), the fusion and fixation of lumbar spinal segments have produced a plethora of devices and techniques that involve transpedicular screws, plating, wiring, and interbody implants. Mechanical testing of these systems confirmed their rigidity (but not in all loading conditions) and their fatigue resistance (Brantigan; Enker; Jeanneret; Rahmatalla; Ruland; Sadeghipour; Zdeblick).
The chosen device and implantation technique never depends on the patient’s pathology. As presented during international spinal teaching conferences, not infrequently much too large surgical interventions are performed on patients with signs and symptoms of an identical condition related to the degenerative discogenic syndrome. For one and the same degenerative discogenic condition, both the device and its whole implanting machinery depend on the surgeon’s training, the limitation of knowledge regarding the advantages and disadvantages of the devices by their teachers, the indoctrination by each manufacturing company, and not to forget, the financial gains when a certain number of devices are implanted. Having been a consultant for a few of such companies, the author is not surprised that the statement ‘abnormal treatment behaviour may be the result of abnormal diagnostic behaviour’ has been translated in huge business.
The most common spinal surgical approaches to lumbar spinal fusion are:
Posterolateral lumbar fusion (PLF) was first practisede in the 1930s. The posterolateral arthrodesis using autologous and other types of bone grafts with or without adjunctive internal stabilisation with all sorts of hardware (hooks, wires, pedicle-screw-based) fuses together the transverse processes. These fusions become painful again in the postoperative period because nothing is done to stop the inflammatory processes in the degenerating disc. Because the symptomatic degenerated and disrupted disc is left ‘alone’, these fusions engender motion, are deficient during multiple daily loading conditions, and compromise the stability of the fusion.
The anterior lumbar interbody fusion (ALIF) was first described by the famous surgeon Capener of Exeter, UK, in 1932. However, if a solid fusion can be achieved, a (stand-alone) anterior lumbar interbody fusion is known to be complicated by subsidence, even in the presence of supplementary osteoinductive graft proteins, and to interfere with the lumbar stability in extension and axial rotation.
Other types of lumbar intervertebral disc excisions and intervertebral fusions (IF) replacing the disc with bone grafts and/or instrumentation (interbody fusion cage/mesh) were introduced over time. The posterior lumbar interbody fusion (PLIF) was introduced in 1944, transforaminal lumbar interbody fusion (TLIF), extraforaminal lumbar interbody fusion (ELIF), and extreme lateral interbody fusion (XLIF) in the 2000s. A global circumferential, or 360° approach, combining anterior and posterior techniques, is offered as well to attempt the intervertebral fusion (Christensen; Slosar; Videbaek).
All techniques use some kind of bone grafts, osteoinductive graft proteins, plates, pedicle and facetal screws, hooks, rods, and cages of all imaginable forms. Therefore, each technique has its specific limitations, failures, complications and re-intervention rates. Astonishingly, no significant differences in outcomes are known among the different surgical techniques.
No doubt other techniques will be developed until an appropriate and simple biological approach will become available. Indeed, and as Einstein suggested in 1929: ‘Because knowledge is limited, intuitions, aspirations and imagination remain important’.
48. Would spinal surgeons opt for spinal fusion for themselves?
How would physicians and spinal surgeons treat themselves if they were suffering signs and symptoms of chronic degenerative discogenic LBP and were diagnosed to have degenerative intradiscal, annular and endplate fissures? Although surveys indicate that over 60 % of physicians report personal experience of LBP, only 1 % will stay in bed for longer than 5 days and less than 1 % will decide to have surgery done to their lumbar spine.
In 2014, a real-time survey of the 133 members of the American Orthopaedic Association in attendance at their symposium was organised before and after multiple lectures. The surgeons were asked what treatment they would prefer for themselves if they had unrelenting LBP from a single degenerative disc at L5-S1 that was affecting their activities of daily living (Boden). Seven per cent of them stated that they would choose disc replacement, 12 % anterior spinal arthrodesis, 35 % posterior spinal arthrodesis, and the remaining 47 % chronic pain management.
There must be a reason why highly trained spinal surgeons so strongly differ in their attitudes for dealing with one and the same condition. Whatever it might be, all physicians, all spinal surgeons, and all key opinion leaders in the spinal surgical field I met, advocate the whole range of conservative measures, fusions and disc prostheses to millions of patients suffering an identical non-lethal and not disabling condition.
49. Fusion: any indications?
Everybody in society knows of somebody’s life having been destroyed by spinal surgery. The appalling historical record of back surgery is well known to even the relatively uninformed lay person who is quite rightly scared of back surgery. Far too much surgery is performed on far too many people with chronic LBP for far too few cogent reasons (Dickson).
Based on the successes of fusing vertebrae for objective indications such as spinal deformities and fractures, the use of these different spinal fusion procedures was gradually expanded to treat the degenerative metabolic processes in the IVD causing a lumbar degenerative discogenic syndrome (DDS). The main reason? The business market for such human sufferers is huge (Vos)!
However, there is very little objective information to substantiate such fusion approaches for treating the enormous patient population with DDS. A well performed fusion is the ideal surgery in cases of degenerative spondylolisthesis. It decreases pathologic movement and thereby decreases symptoms associated with pathologic movement. But the surgical results for DDS are mediocre at least (Mulholland). Till now, although widely used, medical indications are non-existent for the use of any of the large variety of very sophisticated rigid fusion systems for DDS.
Till now, the only surgical indication for signs and symptoms related to DDS without degenerative spondylolisthesis (Yuan), is ‘my dear, if conservative methods don’t help, I only can operate you’!
Although nobody fully understands the relationships between the different reasons causing (disabling) chronic LBP based on the degenerative metabolic processes in the lumbar IVD, it is thought that simply removing and thus simply unloading a degenerative IVD associated with some kind of rigidisation of lumbar spinal segments, will help the LBP sufferer over the long term to get rid of his/her chronic LBP’. However, it has never been proven!
Indeed, nobody knows which treatment is the best when non-operative measures have failed for DDS. Patients themselves may opt to undergo surgical intervention when conservative treatments have failed. But nobody in the world knows when and why a lumbar fusion-arthrodesis is indicated for DDS. For DDS, objective and rational scientific criteria for lumbar fusion are non-existent and have never been established.
Today, everybody with chronic and persistent LBP is a potential candidate for being treated by a spinal fusion. Wherever in the world, the supply of such patients is endless (Vos). Therefore, it is essential to create or fabricate an indication for fusing vertebral bodies to each other. Since years, the indications remain identical for whatever lumbar approach for chronic LBP due to DDS. The indications remain subjective:
Where are the objective indications?
50. Fusion: mother Nature reacts.
As yet in spite of the continuous technological evolution and progress, spinal researchers have not succeeded in developing a novel approach to deal with the physiological involution of the biochemistry and biomechanics in the degenerating lumbar IVD.
It still is thought that whatever technique that simply can take away the nociceptive IVD and fuse the adjacent vertebrae will cure the underlying, progressing, and unstoppable degeneration of the human spine.
Unfortunately and because of its biomechanical complexity - which is far from understood completely - the spine decides to react differently to the surgically achieved and biomechanically stable constructs than may be anticipated and expected.
Indeed, the final goal may be to surpass Nature. But to achieve this goal, it is essential to first understand the natural evolution of the spine and its IVDs during a lifetime. Nature does not accept the concept of correcting and rigidly fusing the changing spinal biomechanics associated with the degenerative discogenic syndrome. Nature considers the procedure an unhealthy excess and sooner or later will react by creating new problems.
51. Fusion: implants are fixed into living organic material.
It should be noted that implants are fixated, in one way or the other, into a living organic material named vertebral bone. This organic material cannot be treated as a passive boundary condition. Fixing a plate to a vertebral body can by no means be compared to fixing something to a stoned wall. Bone is a living substance that responds to changing circumstances, biomechanically and metabolically. Implants don’t!
Bone has the ability to remodel itself in response to the forces acting on it so that new structures become better adapted to the external loads working on it (Wolff’s law, 1892). If vertebral bone is not loaded to a minimum level of mechanical stresses, e.g. due to reduced mobility or immobility between two vertebral bodies or to the limited mobility of the spinal surgically treated patient, the bone structure reacts as if it is redundant and responds by disappearing (= bone resorption).
Fig. 51. Because of frequent occurrence of ‘bone disappearing phenomena’ due to the incompatibility between implant and vertebral bone, the author had to remove huge amounts of implanted materials.
Indeed, a temporarily - 6 to 12 months - decrease in vertebral bone mineral density (= BMD) is usually seen in the lumbar fusion mass and at adjacent vertebral levels. It seems that the decreasing biomechanical stress concentrations in the fusion mass respect Wolff’s law and initially induce an accelerated regional bone loss phenomenon (Frost). However, in the later stages some kind of bone inducing remodeling process gradually replaces the fusion-induced postoperative osteopenia. (Akeson; Bastian; Boden; Bogdanffy; Borenstein; Chen; Chow; Craven; Dalenberg; Etebar; Farey; Frost; Frymoyer; Ghiselli; Gillet; Hillibrand; Ishihara; Kumar; Lee; Lehmann; Leong; Lipscomb; Myers; Oda; Park; Penta; Rahm; Schlegel; Shono; Singh; Umehara; Wai; Wu; Yang).
52. Fusion: what is a successful result?
The primary goal of a spinal fusion is NOT providing low back pain relief.
The success of fusion surgery, the so-called operative ‘gold standard’ to treat the degenerative discogenic syndrome (DDS), is primarily defined by the occurrence of a rigid arthrodesis between two, three or four vertebrae operated on. However, even in the best hands, the postoperative clinical outcomes are totally unpredictable and ensuring a radiologically solid fusion does not necessarily indicate an excellent outcome (Crock; Fujimaki; O’Brien; Zdeblick). Of course, it always remains possible - but by chance - that a lumbar spinal fusion might have eliminated the source of chronic LBP by removing the degenerated IVD and/or by abolishing the hypo- or hypermobility at that level.
And what if decided not to fuse but to replace the degenerated IVD? Compared to total hip and/or total knee replacement procedures where success means an (almost) complete relief of pain, return to full previous familial, professional and social activities, then invasive spinal non-fusion intervertebral disc replacements are far from a success (Boden). Simply, success for the operated patients is not at all related to what the technical skills of the surgeon can achieve (a fusion is a surgical success), but only relies on their decreased pain and quick return to function.
Unfortunately, there exists no standardized and universal accepted definition of success for whatever type of spinal surgical procedure. In the industrialized world, and only for economic reasons, a surgical success only is related to the length of time off professional activity before and after surgery. Success is not at all related to the severity of the remaining symptoms.
53. Fusion: what are the results?
The results of modern surgical fusion procedures and grafting techniques for chronic LBP related to the degenerative discogenic syndrome are similar all over the world. Especially the published clinical long-term results remain very disappointing.
The scientific literature on all these types of fusions is complex, complicated and contains a huge amount of mostly short-term (no more than 2 years) and a very few long-term (more than five years) evaluations.
Although there is no doubt that the continuous development of even more modern techniques and materials results in achieving a perfect intervertebral fusion in excess of 90 % (Burkus; Dimar), all these rigid fusions only result in a very low percentage of patients who obtain a continuing long-term good to excellent result.
The results show an average of ‘some improvement’ in approximately 75 % one to 2 years postoperatively. Thereafter, strangely enough, patients satisfaction definitely declines. The further long-term patient satisfaction becomes mediocre at least and a significant number of patients even become substantially worse. The few existing randomized controlled studies are not enthusiastic and only indicate a very low benefit from spinal fusion compared to non-operative treatments with a minus -10 % to 20 % success (Brox; Fairbank; Fritzell; Gibson; Mirza). Indeed, there only is very limited evidence that in the long-term intervertebral fusion surgery has more to offer than nonsurgical procedures in chronic LBP due to the degenerative discogenic syndrome. Satisfactory long-term results (5 to 10-years) are still awaited (Axellson; Cloward; Crock; Flynn; Freemont; Gibson; Greenough; Hanley; Kostuik; Kozak; MacNab; Mahvi; Mirza; Mulholland; Nordin; Sato; Sengupta; Stokes; Watkins; Weatherley; Zdeblick).
These results indicate a lower than the known satisfying effect of a placebo which is in the order of 35 % to 65 % (Barker; Beecher; Pollo).
54. Fusion: does wishful thinking prevail?
Since the beginning of the 20th century, the illusive hope still remains that one day a perfect rigid intervertebral fusion system will be able to relieve the patient forever from his LBP once the culprit - the progressively degenerating IVD - has been removed.
It is an illusion to hope that a rigid pedicle fixation system will be durable when an intervertebral fusion is performed only to eliminate motion in a spinal condition that solely is characterized by painful degenerative and inflammatory processes inside the IVD (and thus without spondylolisthesis).
The author wonders how the stability of the lumbar spine can be restored once essential motion in one or more of its spinal segments is removed all together. There always will be inherent problems with both the surgical destructive implantation methods and the long-term rigidity at and away from the fusion site (Chou; Sénégas).
However, standard test protocols including in vitro laboratory studies, finite element analyses, and in vivo clinical evaluations will one day succeed in developing very simple, safe, and biomechanical effective spinal surgical implants once the scientists take into account not only the biomechanical but essentially the biochemical causes of the degenerating disc (Goel; Grauer; Wilke).
55. Fusion can make your condition worse.
There is no medical condition that can be made worse by the actual existing high tech surgical fusion methods than the condition related to the degenerative lumbar intervertebral disc: the degenerative discogenic syndrome (DDS).
Failure to obtain relief of pain in the low back, the leg or both may have multiple reasons. The most important is the wrong surgical indication based solely on technical imagery.
A degenerated lumbar IVD can result in abnormal translational and angular motions during all normal daily loading activities. But these abnormal lumbar spinal motions are seen as well in all individuals all over the world who never or rarely experience LBP but whose radiographs present degenerating and degenerated IVDs. On the other hand, motion has never been explained as a source of pain except in those who fractured their vertebrae due to an accident or a cancerous process. Moreover, the DDS is not at all an ‘unstable’ condition. As a consequence, excising the culprit IVD and eliminating hypo- or hypermobility motion between the adjacent vertebrae is not a guarantee for eradicating LBP.
A perfectly performed fusion - whatever type by whatever means and by the best surgeon in the world - is not a guarantee for a perfect clinical success (Brox; Carragee; Fairbank; Fritzell; Mirza). A successful patient-related outcome remains totally unpredictable. There is no convincing evidence at all that whatever type of fusion surgery may and can uniformly relieve LBP of degenerative discogenic origin. On the contrary, continuing pain is a frequent presentation following a technically successful performed fusion.
Millions of chronic LBP sufferers underwent some kind of perfect fusion without any benefit whatsoever. Then, of course, this failed condition needs to be treated as well. For this reason it has been given a scientific name as well: ‘failed back surgery syndrome’. Failed surgery usually is the start of a vicious circle of never ending medical investigations, medical, surgical and psychological advices.
The long-term results of reoperation (2 to 27 years) for failed surgery are poor. In cases of the so-called failed back surgery syndrome (better defined as the ‘clinically non-understood LBP syndrome’), electrodes can be transcutaneously implanted on the dura of the spinal cord and connected to programmable generator. This very expensive spinal cord stimulation (SCS) procedure is performed based on the principles of the ‘pain gate control THEORY’ which explains that, by stimulating the large afferent fibers in the dorsal column of the spinal cord, chronic leg pain may be attenuated or settled. However, the benefits are extremely low and there is no (scientific) evidence that SCS is any better than placebo.
56. Fusion: why failures?
Historically, surgical intervertebral fusion techniques never attempted to restore or neutralise the biology nor the function of the degenerated lumbar intervertebral disc. By sacrificing its function, it significantly alters the functional biomechanics at the fused level(s) and of the lumbar spine. Hence, spinal fusion is not a benign but a destructive procedure.
The highly-trained surgical staff will always consist of human beings dealing with the most complex human anatomical structures requiring extensive dissections to identify anatomic landmarks for implanting all kind of machineries as well as for grafting procedures. But in order to avoid as much failures and complications as possible, multiple different surgical and anatomical approaches are continuously been designed to allow spinal surgeons implanting all these high technically engineered devices more easily by using more and more sophisticated imaging technology.
But whatever the improvements in the technology of spinal fusion for DDS, potentially resulting in significantly less operative time, less blood loss, and less hospital stay, the significant intrinsic and iatrogenic (neurologic and vascular) complications and morbidity of the fusion techniques will always remain the same:
The author does not consider adjacent disc degeneration and epidural fibrosis as complications. Epidural fibrosis is the formation of scar tissue adjacent to the dura and nerve root. Because it is always present to a certain extent (as part of the healing process), it very rarely is the reason of postoperative recurrent symptoms, unless fibrous tissues may contain a traumatised nerve root or dura.
57. Fusion: low back muscle injury
Low back muscle injury occurs in all patients who undergo posterior lumbar surgery. Significant paraspinal muscle disruption - denervation, edema, atrophy, and decrease in muscle mass (multifidus and longissimus muscles) - impairs the spinal balance at the operated levels and decreases trunk muscle strength (Chou; Chow; Dekutoski; Frymoyer; Gejo; Glazer; Hinkley; Katz; Kawaguchi; Kim; Lu; Maigne; Mayers; Penta; Rantanen; Sihvonen; Steven; Styf; Weinhoffer).
58. Fusion: what about the lumbar sagittal lordosis?
In the preoperative period, radiographs of the lumbar spine are taken with the patient in the standing position to determine the actual sagittal balance. However, it is not possible to know what the normal sagittal balance would be if the patient were asymptomatic.
Lateral radiographs, made in patients without LBP and while they were standing and sitting, have shown a broad range of lumbar lordosis in aggregate and a broad range of disc angulation for each disc between L1 and the sacrum.
During lumbar spinal fusion surgery, the lordosis may be maintained, increased or decreased. This approximation is only a guess as to what the asymptomatic sagittal balance might have been.
The arthrodesis allows for only one static lordotic angle and does not permit the dynamic changes in lordosis that occur in different positions during the normal daily activities (e.g. sitting, standing, walking lying down). The arthrodesis may even compromise the overall spinal balance (Cunningham).
59. Fusion: what about degenerative discogenic instability?
There exists no such thing like the so-called degenerative discogenic instability. The degenerative processes in the lumbar IVD first lead to segmental hypermobility and finally evolve to hypomobility (Kirkaldy-Willis).
A precise understanding of what exactly constitutes the term ‘degenerative discogenic instability’ remains elusive. It is a biomechanical term developed in the laboratories for research purposes. But for unknown reasons the term has been translated to the clinical and surgical vocabulary. As the long-term clinical benefits of all fusion techniques for DDD still need to be proven, there remains an insufficient basis to support the idea that whatever type of arthrodesis will control an aging and degenerative process causing hyper- and hypomobility (Bono; Hanley).
Moreover, the author knows of no surgeon who was able to define clinical instability related to the degenerative lumbar spine. Instability related to spinal conditions associated with fractures of the spine, spondylolisthetic situations, and spinal tumors is evident: you even can see it! In these situations spinal fusions result in very rewarding outcomes.
Fused intervertebral discs lack the natural and physiologic functions of non-fused IVDs: they restrict segmental functional mobility. Spinal fusion devices alter and disturb the spinal motions which may lead to spinal stiffening and permanent spinal motion restriction. But because such impairment is amply compensated by the compliance of the adjacent intervertebral levels and by the relatively enormous reserve of mobility provided by the hip joints in flexion-extension, only a few researchers are interested in developing innovative (biological) tools to preserve and control the intervertebral hyper- or hypomobility.
I refer to the separate chapter