• Is a hydrostatic, load bearing structure between the vertebral bodies from C2-3 to L5- S1 .• Is relatively avascular structure and the Essential minerals and fluids required for regeneration enter the disks passively during the night.
Vital Functions of the IVD 1-It supports the axial load on the column that is delivered by the body mass. 2- Assist a limited range of motion at the spine. 3- Shock absorbing system. 4- Serve ligamental functions between vertebral bodies. 5- Assist to keep the normal shape & curvature of each spinal region (cervical, thoracic, ..etc) The Biochemical Composition• Water : 65 ~ 90% wet wt.• Collagen : 15 ~ 65% dry wt.• Proteoglycan : 10 ~ 60% dry wt.• Other matrix protein : 15 ~ 45% dry wt.
Annulus Fibrosus Outer boundary of the disc. More than 60 distinct, concentric layer of overlapping lamellae of type I collagen. Fibers are oriented 30-degree angle to the disc space. Helicoid pattern. Resist tensile, torsional, and radial stress. Attached to the cartilaginous and bony end-plate at the periphery of the vertebra.
Nucleus Pulposus Type II collagen strand + hydrophilic proteoglycan. Water content 70 ~ 90% Confine fluid within the annulus. Convert load into tensile strain on the annular fibers and vertebral end-plate.
Distribution of load inthe intervertebral disc. (A) In the normal, healthy disc,the nucleus distributes the loadequally throughout the anulus. (B) As the disc undergoesdegeneration, the nucleus losessome of its cushioning abilityand transmits the loadunequally to the anulus. (C) In the severely degenerateddisc, the nucleus has lost all ofits ability to cushion the load,which can lead to discherniation.
Is a medical condition affecting the spine due to trauma, lifting injuries, or idiopathic, in which a tear in the outer, fibrous ring (annulus fibrosus) of an intervertebral disc allows the soft, central portion (nucleus pulposus) to bulge out beyond the damaged outer rings. This tear in the disc ring may result in the release of inflammatory chemical mediators which may directly cause severe pain, even in the absence of nerve root compression . Disc herniations are normally a further development of a previously existing disc "protrusion", a condition in which the outermost layers of the annulus fibrosus are still intact, but can bulge when the disc is under pressure.
Types of herniation posterolateral disc herniation – protrusion is usually posterolateral into vertebral canal, compress the roots of a spinal nerve. protruded disc usually compresses next lower nerve as that nerve crosses level of disc in its path to its foramen. (eg.protrusion of fifth lumbar disc usually affects S1 instead. central (posterior) herniation: less frequently, a protruded disc above second lumbar vertebra may compress spinal cord itself or or may result in cauda equina syndrome. in the lower lumbar segments, central herniation may result in S1 radiculopathy. lateral disc herniation: may compress the nerve root above the level of the herniation L4 nerve root is most often involved & patient typically have intense radicular pain.
Classifications Of Herniations Degeneration Loss of fluid in nucleus pulposus. Protrusion Bulge in the disc but not a complete rupture. Prolapse Nucleus forced into the outermost layer of the annulus fibrosus- not a complete rupture. Extrusion the gel-like nucleus pulposus breaks through the tire- like wall (annulus fibrosus) but remains within the disc. Sequestration Disc fragments start to form outside of the disc area.
Cellular and Biochemical Changes of the Intervertebral Disc Decrease proteoglycan content. Loss of negative charged proteoglycan side chain. Water loss within the nucleus pulposus. Decrease hydrostatic property. Loss of disc height. Uneven stress distribution on the annulus.
CAUSES Repetitive mechanical activities – Frequent bending, twisting, lifting, and other similar activities without breaks and proper stretching can leave the discs damaged. Living a sedentary lifestyle – Individuals who rarely if ever engage in physical activity are more prone to herniated discs because the muscles that support the back and neck weaken, which increases strain on the spine. Traumatic injury to lumbar discs- commonly occurs when lifting while bent at the waist, rather than lifting with the legs while the back is straight.
CAUSES Obesity – Spinal degeneration can be quickened as a result of the burden of supporting excess body fat. Practicing poor posture – Improper spinal alignment while sitting, standing, or lying down strains the back and neck. Tobacco abuse – The chemicals commonly found in cigarettes can interfere with the disc’s ability to absorb nutrients, which results in the weakening of the disc. Mutation- in genes coding for proteins involved in the regulation of the extracellular matrix, such as MMP2 and THBS2, has been demonstrated to contribute to lumbar disc herniation.
Pathophysiology There is now recognition of the importance of “chemical radiculitis” in the generation of back pain. A primary focus of surgery is to remove “pressure” or reduce mechanical compression on a neural element: either the spinal cord, or a nerve root. But it is increasingly recognized that back pain, rather than being solely due to compression, may also be due to chemical inflammation.
There is evidence that points to a specific inflammatory mediator of this pain. This inflammatory molecule, called tumor necrosis factor-alpha (TNF), is released not only by the herniated disc, but also in cases of disc tear (annular tear), by facet joints, and in spinal stenosis. In addition to causing pain and inflammation, TNF may also contribute to disc degeneration.
Epidemiology• Disc herniation can occur in any disc in the spine, but the two most common forms are lumbar disc herniation and cervical disc herniation.• The former is the most common, causing lower back pain (lumbago) and often leg pain as well, in which case it is commonly referred to as sciatica.• Lumbar disc herniation occurs 15 times more often than cervical (neck) disc herniation, and it is one of the most common causes of lower back pain.• The following locations have no discs and are therefore exempt from the risk of disc herniation: the upper two cervical intervertebral spaces, the sacrum, and the coccyx.
Epidemiology Most disc herniations occur when a person is in their thirties or forties when the nucleus pulposus is still a gelatin-like substance. With age the nucleus pulposus changes ("dries out") and the risk of herniation is greatly reduced. After age 50 or 60, osteoarthritic degeneration (spondylosis) or spinal stenosis are more likely causes of low back pain or leg pain. 4.8% males and 2.5% females older than 35 experience sciatica during their lifetime. Of all individuals, 60% to 80% experience back pain during their lifetime. In 14%, pain lasts more than 2 weeks. Generally, males have a slightly higher incidence than females.
Diagnosis & management Diagnosis is based on the history, symptoms, and physical examination. At some point in the evaluation, tests may be performed to confirm or rule out other causes of symptoms such as spondylolisthesis,degeneration, tumors, metastases and space-occupying lesions.
symptoms of a herniated disc can vary depending on the location of the herniation and the types of soft tissue that become involved. They can range from little or no pain if the disc is the only tissue injured, to severe and unrelenting neck or low back pain that will radiate into the regions served by affected nerve roots that are irritated or impinged by the herniated material. Often, herniated discs are not diagnosed immediately, as the patients come with undefined pains in the thighs, knees, or feet.
sensory changes such as numbness, tingling, muscular weakness, paralysis, paresthesia, and affection of reflexes. If the disc protrudes to one side, it may irritate the dural covering of the adjacent nerve root causing pain in the buttock, posterior thigh and calf (sciatica). Unlike a pulsating pain or pain that comes and goes, which can be caused by muscle spasm, pain from a herniated disc is usually continuous or at least is continuous in a specific position of the body.
A large central rupture may cause compression of the cauda equina. A posterolateral rupture presses on the nerve root proximal to its point of exit through the intervertebral foramen; thus a herniation at L4/5 will compress the fifth lumbar nerve root, and a herniation at L5/S1, the first sacral root. Sometimes a local inflammatory response with oedema aggravates the symptoms. …………………………………………………………………..
ACUTE DISC PROLAPSE• Acute disc prolapse may occur at any age,commonly between 20-45 but is uncommon in the extreme of ages.• Typically, while lifting or stooping .
CLINICAL FEATURES• The patient has severe back pain and is unable to straighten up.• Radiating pain to the buttock and lower limbs and is associated with paraesthesia or numbness in the legs or foot( sciatica) and occasionally there is muscle weakness.• Both backache and sciatica are made worse by coughing or straining.• Cauda equina compression is rare but may cause urinary retention and perineal numbness.
CLINICAL FEATURES• The patient usually stands with a slight list to one side(‘sciatic scoliosis’).• Sometimes the knee on the painful side is held slightly flexed to relax tension on the sciatic nerve; straightening the knee makes the skew back more obvious.• All back movements are restricted, and during forward flexion the list may increase.
CLINICAL FEATURES• There is often tenderness in the midline of the low back, and paravertebral muscle spasm.• Straight leg raising is restricted and painful on the affected side; dorsiflexion of the foot and bowstringing of the lateral popliteal nerve may accentuate the pain.• Sometimes raising the unaffected leg causes acute sciatic tension on the painful side (‘crossed sciatic tension’).• With a high or mid-lumbar prolapse the femoral stretch test may be positive.
CLINICAL FEATURES• Neurological examination may show muscle weakness (and, later, wasting), diminished reflexes and sensory loss corresponding to the affected level.• L5 impairment causes weakness of knee flexion and big toe extension as well as sensory loss on the outer side of the leg and the dorsum of the foot.
CLINICAL FEATURES– Normal reflexes at the knee and ankle are characteristic of L5 root compression.– Paradoxically, the knee reflex may appear to be increased, because of weakness of the antagonists (which are supplied by L5).– S1 impairment causes weak plantar-flexion and eversion of the foot, a depressed ankle jerk and sensory loss along the lateral border of the foot.
FEATURES OF CAUDA EQUINA SYNDROME Bladder and bowel incontinence Perineal numbness Bilateral sciatica . Lower limb weakness Crossed straight-leg raising sign Note: Scan urgently and operate urgently if a large central disc is revealed.
Location The majority of spinal disc herniation cases occur in lumbar region (95% in L4-L5 or L5-S1). The second most common site is the cervical region (C5-C6, C6-C7). The thoracic region accounts for only 0.15% to 4.0% of cases.
. posterolateral herniation between two vertebrae will actually impinge on the nerve exiting at the next interverte bral foramen down. Occasionally an L4/5 disc prolapse compresses both L5 and S1.
Cervical Cervical disc herniations occur in the neck, most often between the fifth & sixth (C5/6) and the sixth and seventh (C6/7) cervical vertebral bodies. Symptoms can affect the back of the skull, the neck, shoulder girdle, scapula, shoulder, arm, and hand. The nerves of the cervical plexus and brachial plexus can be affected.Thoracic Thoracic discs are very stable and herniations in this region are quite rare. Herniation of the uppermost thoracic discs can mimic cervical disc herniations, while herniation of the other discs can mimic lumbar herniations.
Lumbar Lumbar disc herniations occur in the lower back, most often between the fourth and fifth lumbar vertebral bodies or between the fifth and the sacrum. Symptoms can affect the lower back,buttocks, thigh, anal/genital region (via the Perineal nerve), and may radiate into the foot and/or toe. The sciatic nerve is the most commonly affected nerve, causing symptoms of sciatica. The femoral nerve can also be affected and cause the patient to experience a numbness, tingling feeling throughout one or both legs and even feet or even a burning feeling in the hips and legs.
DISC LOAD IN DIFFERENT BODY POSTURE When the spine is straight, such as in standing or lying down, internal pressure is equalized on all parts of the discs. While sitting or bending to lift, internal pressure on a disc can move from 17 (lying down) to over 300 psi (lifting with a rounded back).
Physical Examinations Finding include positive straight leg raise (lasegue sign) which is the most predictive finding if it reproduces leg pain for HNP with L5 or S1 radiculopathy. as this finding has low specificity; however, it has high sensitivity. Thus the finding of a negative SLR sign is important in helping to "rule out" the possibility of a lower lumbar disc herniation.
Examination With thepatient standing uprightlook at his general postureand note particularly thepresence ofany asymmetry or frankdeformity of the spine .
Hold the pelvisstable and ask thepatient to twist firstto one side and thento the other(rotation).
With the patient upright, select two bony points 10 cm apart and mark the skin asthe patient bends forward, the two points should separate by at least a further 5 cm.
Examination with the patient prone(a) Feel for tenderness, watching the patient’s face for any reaction.(b) Performing the femoral stretch test.You can test for lumbar root sensitivity either by hyperextending the hip or byacutely flexing the knee with the patient lying prone.Note the point at which the patient feels pain and compare the two sides. (c) While the patient is lying prone, take the opportunity to feel the pulses. Thepopliteal pulse is easily felt if thetissues at the back of the knee are relaxed by slightly flexing the knee.
Sciatic stretch tests (a) Straight-leg raising. The A B knee is kept absolutely straight while the leg isslowly lifted (or raised by thepatient himself); note where the patient complains of tightness and pain in the buttock – this normally occurs around 80 or 90°. (b) At that point a more acute stretch can be applied by passively dorsiflexing the foot – this may cause an added stab of pain. C D (c) The‘bowstring sign’ is a confirmatory test for sciatic tension. At the point wherethe patient experiences pain,relax the tension by bending the knee slightly; the painshould disappear. Then apply firm pressure behind thelateral hamstrings to tightenthe common peroneal nerve (d); the pain recurs with renewed intensity.
X-Ray : lumbo-sacral spine; Narrowed disc spaces. Loss of lumber lordosis. Compensatory scoliosis.CT scan lumber spine; It can show the shape and size of the spinal canal, its contents, and the structures around it, including soft tissues. Bulging out disc.MRI lumber spine; Intervertebral disc protrusion. Compression of nerve root.Myelogram; pressure on the spinal cord or nerves, such as herniated discs,tumors, or bone spurs.
medical treatments. Bed rest. Non-steroidal anti-inflammatory drugs (NSAIDs). Patient education on proper body mechanics. Physical therapy, to address mechanical factors, and may include modalities to temporarily relieve pain (i.e. traction, electrical stimulation massage). Oral steroids (e.g. prednisone or methylprednisolone). Epidural cortisone injection. Intravenous sedation, analgesia-assisted traction therapy (IVSAAT). Weight control. Tobacco cessation. Lumbosacral back support. anti-depressants.
Indication of SurgeryIdeal candidate• history, physical examination, radiographic finding, are consistent with one another• when discrepancy exist, the clinical picture should serve as the principal guide.Absolute surgical indication• cauda equina syndrome.• acute urinary retension/incontinence, saddle anesthesia, back/buttock/leg pain, weakness, difficulty walking.Relative indication• progressive weakness.• no response to conservative treatment.
The objectives of surgical treatment1. relief of nerve compression.2. allowing the nerve to recover.3. relief of associated back pain.4. restoration of normal function.
Chemonucleolysis-• Chemonucleolysis is the term used to denote chemical destruction of nucleus pulposus .• This involves intradiscal injection of chymopapain which causes hydrolysis of he cementing protein of the nucleus pulposus.• This causes decrease in water binding capacity leading to reduction in size and drying the disc.• Chemonucleolysis is one of the methods to treat disc herniation not responding to conservative therapy.
Intradiscal electrothermic therapy (IDET) IDET is a minimally invasive outpatient surgical procedure developed over the last few years to treat patients with chronic low back pain that is caused by tears or small herniations of their lumbar discs. provides a new alternative and a dvanced procedure made possible by the development of electrothermal catheters that allow for careful and accurate temperature control. The procedure works by cauterizing the nerve endings within the disc wall to help block the pain signals
Discectomy/Microdiscectomy -• This procedure is used to remove part of an intervertebral disc that is compressing the spinal cord or a nerve root.
The Tessys method• The Tessys method (transforaminal endoscopic surgical system) is a minimally invasive surgical procedure to remove herniated discs .
Laminectomy-to relieve spinalstenosis or nervecompression
Hemilaminectomy - Hemilaminectomy is surgery to help alleviate the symptoms of an impinged or irritated nerve root in the spine
Lumbar fusion• Anterior lumbar fusion is an operation done on the front (the anterior region) of the lower spine.• Fusion surgery helps two or more bones grow together into one solid bone.• Fusion cages are new devices, essentially hollow screws filled with bone graft, that help the bones of the spine heal together firmly.• Surgeons use this procedure when patients have symptoms from disc degeneration, disc herniation, or spinal instability.• lumbar fusion is only indicated for recurrent lumbar disc herniations, not primary herniations
Disc arthroplasty• Artificial Disc Replacement (ADR), or Total Disc Replacement (TDR), is a type of arthroplasty.• It is a surgical procedure in which degenerated intervertebral discs in the spinal column are replaced with artificial devices in the lumbar (lower) or cervical (upper) spine.• The procedure is used to treat chronic, severe low back pain and cervical pain resulting from degenerative disc disease.• Used for cases of cervical disc herniation.
Dynamic stabilization• Dynamic stabilization is a surgical technique designed to allow for some movement of the spine, while maintaining enough stability to prevent too much movement.• If you need to undergo surgery for spinal disc problems, you may also need added stabilization of the spine to prevent additional problems
Nucleoplasty• Nucleoplasty is the most advanced form of percutaneous discectomy developed to date.• Nucleoplasty uses a unique technology to remove tissue from the center of the disc.• Tissue removal from the nucleus acts to “decompress” the disc and relieve the pressure exerted by the disc on the nearby nerve root .• As pressure is relieved the pain is reduced
1-Spine: 15 January 2012 - Volume 37 - Issue 2 - p 140–149 Who Should Have Surgery for an Intervertebral Disc Herniation?:• Comparative Effectiveness Evidence From the Spine Patient Outcomes Research Trial Pearson, Adam MD, MS; Lurie, Jon MD, MS; Tosteson, Tor ScD; Zhao, Wenyan MS; Abdu, William MD, MS; Mirza, Sohail MD, MPH; Weinstein, James DO, MS Abstract• Study Design. Combined prospective randomized controlled trial and observational cohort study of intervertebral disc herniation (IDH), an as-treated analysis. Objective.• To determine modifiers of the treatment effect (TE) of surgery (the difference between surgical and nonoperative outcomes) for intervertebral disc herniation (IDH) using subgroup analysis. Methods.• IDH patients underwent either discectomy (n = 788) or nonoperative care (n = 404) and were analyzed according to treatment received.• Thirty-seven baseline variables were used to define subgroups for calculating the time-weighted average TE for the Oswestry Disability Index (ODI) across 4 years (TE = ΔODIsurgery −ΔODInonoperative).• Variables with significant subgroup-by-treatment interactions (P < 0.1) were simultaneously entered into a multivariate model to select independent TE predictors.
2-The impact of the Spine Patient Outcomes Research Trial (SPORT) results on orthopaedic practice. 2012 Mar;20(3):160-6 Department of Orthopaedic Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA.• AbstractThe benefits of spinal surgery for relief of low back and leg pain in patients with degenerative spinal disorders have long been debated.• The trial studied the outcomes of the surgical and nonsurgical management of three conditions: intervertebral disk herniation, degenerative spondylolisthesis, and lumbar spinal stenosis.• Result;• Both surgical and nonsurgical care of intervertebral disk herniation resulted in significant improvement in symptoms of low back and leg pain.• Still, the treatment effect of surgery for intervertebral disk herniation was less than that seen in patients who underwent surgical versus nonsurgical treatment of degenerative spondylolisthesis and lumbar spinal stenosis.• Across SPORT, more significant degrees of improvement with surgery were noted in chronic conditions of lumbar spinal stenosis and lumbar spinal stenosis with spondylolisthesis.• In addition, no catastrophic progressions to neurologic deficit occurred as a result of watchful waiting.
3-[Lumbar epidural steroid injection: Is the success rate predictable?].Department of Orthopedics and Traumatology, Başkent University, Adana Medical Center, Ankara, Turkey.march 2012 OBJECTIVES: The aim of this study was to determine the relation between the percent of canal compromise and success rate of epidural steroid injection (ESI) in patients with symptomatic lumbar herniated intervertebral discs. RESULTS: 39 patients (14 male, 25 female) were included in this study. The mean age was 50.2±11.6 years (27-76). Twenty-one cases (51%) also had back pain. The mean percent canal compromise ratio was 36.1±2.4%. The mean duration of symptoms was 19.4±6.6 months. There was also a significant negative correlation between percent canal compromise and post-injection VAS (p=0.042). However, there was no correlation between post-injection VAS and age, sex, or location or type of herniation (p>0.05). CONCLUSION: It has been demonstrated that higher benefits of ESI were achieved in patients with short duration of symptoms and high percent of canal compromise.
4-Future treatments may include stem cell therapy.• Doctors Victor Y. L. Leung, Danny Chan and Kenneth M. C. Cheung have reported in the European Spine Journal• that "substantial progress has been made in the field of stem cell regeneration of the intervertebral disc.• Autogenic mesenchymal stem cells in animal models can arrest intervertebral disc degeneration or even partially regenerate it and the effect is suggested to be dependent on the severity of the degeneration.