Nowhere is degeneration better seen than in the intervertebral disc. The disc is the largest avascular structure in the body and functions in the simplest sense as a shock absorber. It is composed of an outer ring or annulus, a central portion referred to as the nucleus pulposus, and two hyaline cartilage end plates. The annulus is made up predominantly of coarse collagen fibres arranged in parallel sheets that interconnect adjacent vertebral bodies. The nucleus is the gelatinous central core, made up of loosely distributed collagen and abundant ground substance. Distributed throughout the disc are cells classified as chondrocytes that produce the extracellular matrix. This extracellular substance is a combination of collagen, proteoglycans, and water. Collagen is responsible for the strength of the disc. The proteoglycan molecule is hydrophilic and functions by keeping the fibrous network pressurized with water so that the disc is able to resist and distribute compression forces.

Since the disc is avascular, its nutrition is supplied by diffusion from the ligaments that surround the periphery of the disc and the vascular subchondral bone. With ageing, however, there is a decrease in the rate of nutritional diffusion to the nucleus pulposus. This decrease in diffusion interferes with the synthesis of collagen and the proteoglycans resulting in desiccation of the disc. As the disc dries out, its efficiency in resisting mechanical loads begins to fail. Stress cracks and crevices develop within the annulus and the facet joints, thereby, have increased forces applied to them.

While these degenerative changes occur in everyone not everyone is symptomatic. The histological and biochemical changes that occur within the spine, in the intervertebral disc, are not simply a deterioration, but may be a remodelling process. The question still remains as to the source of the pain. "Neural inflammation factors" elaborated from the disc as it undergoes the degeneration and direct compression of the neural elements, may stimulate the nociceptive centres and produce pain.

Acute low back pain rarely occurs before the age of 20 and after the age of 60. At times, it may be related to an injury but most often it results from a minor twisting or lifting activity. The pain centres within the low back area with occasional radiation into the buttock and possibly as far as the knee. Any attempt at motion increases discomfort. Spasm within the paraspinal muscles is detectable. Neurological examination rarely shows any deficit in sensory and motor function. Normally, about 1 per cent of patients presenting with acute low back pain have neurological deficit.

There are six categories of low back pain:

(1)spondylogenic

(2)neurogenic

(3)discogenic

(4)psychogenic

(5)transient

(6)visceral

If a patient presents with pain at rest or at night, this is generally not mechanical back pain. One must consider either an infectious process such as an epidural abscess, or spinal osteomyelitis. In addition, neoplastic disease must be considered. Similarly, if a patient seems to be writhing in pain rather than lying still, this picture suggests a visceral aetiology such as renal calculi or an intra-abdominal process. Abdominal palpation of a pulsatile mass should alert one to the possibility of an aortic aneurysm. If the patient has frank neurological deficit and symptoms of urinary retention or incontinence one must consider the possibility of a space-occupying lesion within the canal, such as a herniated disc, an epidural abscess, or a neoplasm.

Although radiographs are routinely ordered, their help in making a diagnosis is minimal. Radiographs should be obtained in all patients with acute low back pain who are over 50 years of age or who have a history of night pain, pain at rest, or serious trauma. The patient that is febrile, has a history of drug or alcohol abuse, or has been on steroid treatment, should undergo an initial radiographic examination.

Only 10 to 20 per cent of patients who present with acute low back pain can be given a precise pathoanatomic diagnosis. The lumbar nerve roots themselves are not affected, and there are no neurological findings in the lower extremities.

A patient with the acute onset of low back pain often has severe pain, but this syndrome usually is self-limiting. Within a 2-week period, 70 per cent of patients are clinically improved and 90 per cent of them are so within a 2-month period. Treatment should be directed with this natural history in mind. The majority of individuals with acute symptoms of back pain respond to a short-term treatment programme which is divided into three phases: initial rest, progressive mobilization, and preventive exercises and education.

Bed rest if recommended is pain is severe, but only for a short course. Bed rest of only 2 days is as effective as a week of bed rest. This treatment may be aided by the use of mild analgesics such as non-steroidal anti-inflammatory medication or mild narcotic. The use of strong narcotics or muscle relaxants is to be avoided. Early activity is encouraged.

Only about 5 per cent of patients with low back pain develop symptoms lasting 3 months or longer. There are several syndromes with a specific clinical picture and radiographic findings that can produce low back pain. These include:

(1)posterior facet syndrome

(2)degenerative spinal arthritis,

(3)segmental instability

(4)disc disruption syndrome,

(5)idiopathic vertebral sclerosis

(6)diffuse idiopathic skeletal hyperostosis

(7)ankylosing spondylitis

(8)fibromyalgia.

With the exception of the last three, all appear to be different manifestations of the same pathophysiology producing an instability of the motion segment of the spine. Pain is produced either by mechanical or chemical irritation to the adjacent nociceptive nerve endings. Treatment is directed at attempting to bring about some stability to the motion segment and thereby decreasing nerve irritation.

The patient is typically a middle-aged individual in the 30 to 60 age group who presents with a chronic low back pain which may be cyclic and possibly related to change in activity. The main pattern is of pain in the low back which may also be referred to the upper portion of the lower extremities but rarely if ever radiates below the knee. Symptoms may typically be aggravated by sitting and there may be gradual resolution of symptoms with rest. Physical examination will often show some restriction of spinal mobility and an increase or aggravation of pain with extension. These symptoms are due to facet syndrome.

In the facet syndrome, patients experience back and leg pain with reproduction of the symptoms by injection of hypertonic saline into the facet joints. These symptoms may often be relieved by an injection of a local anaesthetic into the facet joint.

In the disc disruption syndrome, CT scan myelography or MRI shows a degenerative disc with an annular bulge and possibility of a central disc herniation. Injecting saline into the disc may reproduce the patient's symptoms.

Diagnostic tests for segmental instability include flexion extension films of the spine and are positive when at least 3 mm of displacement is noted moving from the flexed to extended position. This diagnosis may further be documented by facet injection if pain relief is brought about.

Diffuse idiopathic spinal hyperostosis (DISH) is a syndrome that occurs predominantly in men. Patients typically have complaints of considerable stiffness. Radiographs show considerable osteophyte formation anteriorly to the spine, often bridging adjacent vertebrae.

Ankylosing spondylitis will be discussed below. It typically occurs in the male population and affects 2 per cent of the population. These patients often have morning stiffness that clears with activity but then becomes symptomatic towards the end of the day. Radiographs show a diffuse ankylosis, giving the spine the appearance of a bamboo pole.

Idiopathic vertebral sclerosis occurs most commonly in women with disc space narrowing and a rather diffuse sclerosis at the adjacent vertebral body giving the overall radiographic appearance of a chronic infection.

Patients with chronic recurrent low back pain are most often treated without surgery. The use of anti-inflammatory medication is often helpful, as there is almost always an inflammatory reaction present. Exercise is important in improving mobility but is also important in attempting to increase dynamic stability of the spine and attention is directed to both the abdominal and paraspinal muscle groups. Aerobic exercises such as walking, bicycle riding, and swimming are also encouraged because of the positive effects such exercise has on increasing the endorphin levels and thereby decreasing pain. Exercise also seems to have a positive effect on disc nutrition.

The most common procedure is intertransverse process fusion. Spinal fusion may also be brought about with an anterior or posterior lateral interbody fusion. The fused spine may also be stabilized with instrumentation. There are no prospective data documenting the clinical effectiveness of lumbar spinal fusion in patients with low back pain emanating from either lumbar instability or internal disc derangement.

Sciatica is a term referring to pain radiating down the posterior aspect of the leg in the distribution of the sciatic nerve. Besides bringing symptoms of paraesthesia, weakness may also be present. Anterior thigh pain is derived from lesions affecting the femoral nerve and is referred to as crural pain. The differential diagnoses of sciatica include an intraspinal mass proximal to the disc such as lesions affecting the conus or the cauda equina. Lesions at the disc level may include herniated disc, spinal stenosis, discitis, or tumour. Sciatica may also be brought about by extraspinal causes such as lesions within the pelvis: vascular disease, gynaecological conditions, and inflammation or osteoarthritis of the hip joint. Sciatica may also be brought about as a result of systemic abnormalities producing neuritis of the sciatica nerve. Sciatica must be differentiated from referred pain, which usually is due to instability and inflammation of facet joint. Typically, referred pain does not radiate below the knee, may be bilateral, and is not associated with neurological deficit.

Patients with sciatica due to a herniated disc typically are in the 20- to 50-year-old age group and about half of them will attribute the symptoms to some traumatic experience. The majority of patients will have developed some back pain prior to leg symptoms. The pain typically is aggravated with forward bending, lifting, or coughing or sneezing. Pain seems to resolve somewhat in a supine position. Physical examination shows a patient who will stand often with a flattening of the lumbar spine and will often lean away from the site of pain. When standing, the patient will often not put the affected foot permanently on the ground. The major limitations of motion is in flexion. Extension and lateral bend may also produce pain, and muscle spasm may be present. Examination of lower extremity may show muscle atrophy if symptoms have lasted for some time. In addition, there will often be a decrease in sensation with the distribution corresponding to the nerve root dermatome involved. Weakness in specific muscle groups may also be present along with reflex depression. The most sensitive test for determining nerve root irritation is that of a straight leg raise test and the bowstring sign. When performing these tests the patient is supine with knee and hip flexed and then gradually the knee is extended. This will often produce radiating pain down through the legs and it may also radiate up into the back. When one keeps the knee in a somewhat flexed position but applies pressure to the popliteal area, this may also produce similar type pain which is referred to as a bowstring sign. If symptoms are in anterior thigh, one may suspect a high disc lesion. The femoral nerve stretch test is performed with the patient lying prone and gently extending the hip and flexing the knee. If straight leg raising is performed on the contralateral side and produces symptoms, the probability that disc herniation is causing the problem rises to about 98 per cent and is referred to as a positive cross leg raise sign.

Myelography is the gold standard for diagnosis of herniated disc. Probably the best examination is an MRI. This test is not invasive, and there is clear reproduction of the disc and neural elements. Electromyography may be used to localize the level of the nerve root involvement, but gives no information as to the exact site or nature of the lesion.

Sciatica rarely requires surgical treatment unless the symptoms are the result of a massive disc herniation, an epidural abscess, or tumour. Besides pain of an intractable nature, these lesions will often present with changing and progressive neurological symptoms. Fifty per cent of the patients who present with acute sciatica will recover within 6 weeks. Given the overall cost, the patient presenting with sciatica does not need to undergo initial diagnostic tests unless pain is severe or there is a neurological deficit.

About 10 per cent of the patients with persistent unrelenting sciatica require some form of invasive treatment. When comparing patients who had undergone surgery with those who had been treated conservatively, after 2 years patients who had undergone surgery for herniated disc have better function and fewer symptoms than the non-surgical group. At 4 years, however, the two groups are similar.

Unless the patient has significant progressive neurological deficit or severe intractable pain, diagnostic testing should be delayed for at least 3 to 4 weeks and performed at that point only when non-invasive treatment is considered. If at 4 to 6 weeks, symptoms have not resolved and the diagnostic test correlates with clinical picture, invasive procedures may be recommended. Invasive procedures for treatment of disc herniation include percutaneous discectomy, microdiscectomy, and traditional discectomy. Which procedure is employed in the treatment of sciatica appears to be less important than a careful evaluation of the patient. In the VENN diagram (Fig. 1) 2488, the shaded area represents a patient who has a positive straight leg raise together with objective neurological signs and a positive diagnostic study. In 90 per cent of such patients, surgical treatment is associated with success.

This procedure involves decompression of herniated disc by an automatic suction device. This is also carried out under local anaesthetic under strict radiographic control. It is indicated only in patients who have contained disc herniation; i.e, there are no free fragments present. The procedure is contraindicated if there are signs of spinal stenosis. Percutaneous discectomy has the advantages of chemonucleolysis without the risk of allergic reaction or transverse myelitis. Initial reports have listed success rates in the 70 to 80 per cent range.

A modification of a formal surgical discectomy is performed using a small incision under microscopic viewing. It is an attempt to decrease hospital stay by producing less surgical trauma and less postoperative scarring. The procedure is performed most commonly under general anaesthesia but may be carried out under a local anaesthetic in a prone kneeling position.

This is a procedure performed similar to microdiscectomy but with a slightly larger incision without use of a microscope but with magnification loupes. A small amount of bone may be removed from the lamina in order to identify the nerve root. This procedure allows clear identification of the lateral border of the nerve root. Following removal of the disc, the nerve root is examined and followed into the foramen to make sure that there are no free fragments or compression of the nerve root in the lateral recess.

There is little place for formal laminectomy in the treatment of disc disease. It is recommended only in cases of spinal stenosis, which will be discussed below. The outcome of invasive treatment of disc herniation and sciatica have to do with the experience of the surgeon, accurate knowledge of anatomy, and use of proper instrumentation. Poor results following invasive treatment may be due to presence of retained fragment or failure to decompress a nerve root that is compressed in the foramen by a hypertrophic facet. Overall, the best results can be expected using conventional discectomy with magnification loupe and removing only as much bone as necessary to be sure the nerve root is free. Fusion is rarely indicated in the treatment of sciatica for lumbar disc disease.

Spinal stenosis refers to narrowing of the spinal canal, the nerve root canal, and/or the invertebral foramen within the spine. It generally affects people over the age of 60 years. Narrowing of these structures is due to bone overgrowth, generally at the facet joint. Hypertrophy may also involve the lamina and soft tissues that encroach upon the spinal canal; these include the ligamentum flavum and capsule of the facet joint. The stenosis may involve one level or it may be segmental and be diffuse along the entire lumbar spine. Stenosis may also be due to congenital abnormality within the spine and this may be seen in such cases as achondroplasia. Much more commonly, stenosis is brought about by a degenerative process as the end result of the degenerative changes within the spine. Stenosis may also be brought about as the result of scarring after laminectomy or spinal fusion. Lastly, stenosis may occur as a result of a burst-type fracture of the lumbar spine.

The diagnosis of spinal stenosis can easily be made on the basis of history. Patients present themselves with complaints of pain, occasional numbness, and a feeling of weakness in lower extremities that is brought about by standing or walking and relieved with sitting or flexion of the spine. A major differential is vascular claudication, the difference being that the patient with vascular claudication merely needs to stop walking to have relief of symptoms, but with spinal stenosis, the patient really has to sit or to assume a flexed position. Symptoms can often be recreated on physical examination merely by placing the patient standing in an extended position. Patients with stenosis often stand in a somewhat forward flexed position. Symptoms may involve one leg but are more often bilateral. The examination generally does not reveal signs of sensorimotor deficit. Although reflexes are generally intact, one may provoke the symptoms by having the patient stand or walk over a period of minutes until they become symptomatic; neurological changes may then often be noticed.

In addition to the history and physical examination radiography can often show degenerative changes. There may be findings in addition to the degenerative process if the aetiology is spondylolisthesis or burst fracture. Non-contrast CT scan will show evidence of bony impingement but soft tissue ligamentous structures add to the problem. Patients with bona fide stenosis may appear to have a fairly normal CT scan. The most definitive test is a postmyelogram CT scan which demonstrates soft tissues within the canal and a cross-sectional measure of the canal can be obtained. Symptoms of stenosis generally occur when cross-sectional area is 100 mm² or less at the L3 level. MRI is also helpful in delineating cross-sectional area. EMG may be helpful if it is carried out after a patient has been standing or walking for a period of time. Spinal evoked potential may also be used for diagnostic purposes though its reliability is not yet established.

The most common form of spinal stenosis is acquired degenerative stenosis. The spinal canal becomes narrow as a result of thickening of the ligamentum flavum, bulging of the intervertebral disc, and spur formation around the facet joint. Once the canal narrows, the cross-sectional area decreases and nerve root compression can develop. Nerves within the cauda equina do not have a myelin sheath and are therefore more susceptible to compression than are the peripheral nerves.

In general, unless the patient is having acute sciatic irritation, bed rest is of little value. Patients generally find by themselves that most activities are best carried out in a flexed or sitting position and extending the spine reproduces symptoms of stenosis. Oral corticosteroids may also be used for short periods if tapered rapidly. Analgesics generally are not needed nor are muscle relaxants, as the majority of patients can find relief of the symptoms by changing position. Braces and corsets may be used and may help to relieve symptoms if they are able to place the spine in a somewhat forward flexed position. Exercise is generally recommended to strengthen abdominal muscles and decrease lumbar lordosis.

Decompression has a wide variability of results, with good results ranging from 60 to 95 per cent. Decompression is carried out into the lateral recess leaving more bone exposed posteriorly than anteriorly. This tends to decrease postoperative scar. Surgical decompression consists of eliminating all bone and soft tissue compressing the nerve root and follows the nerve root into the foramen. Care should be taken to preserve the integrity of the facet joint complex. Disc excision is not necessary and may actually lead to postoperative morbidity by increasing instability.

After the posterior structures have been removed, fusion techniques include a posterior lateral fusion or interbody fusion. Anterior interbody fusion requires a separate surgical procedure via a transabdominal surgical approach. Internal fixation is used in an attempt to improve fusion rates and allow early mobilization. Frequently posterior elements have been removed necessitating the use of spinal instrumentation. While the use of spinal instrumentation is appealing, the risk/benefit ratio must again be considered. In addition, most of the devices for instrumentation of the spine fail if satisfactory fusion is not achieved. Care must be taken to provide a solid fusion.

Degenerative processes in the cervical spine parallel those in the lumbar region. Such terms as cervical strain, soft disc, and spondylosis are really all manifestations of the degenerative process. Degeneration is an ongoing process that becomes clinically symptomatic if the biomechanical stresses are excessive or abnormal. Pain develops as a result of mechanical or chemical irritation to nociceptive nerve endings in the facet joints, interspinous ligament, or the outer layers of the intervertebral disc. Pain may be neurogenic when the spinal cord or nerve roots are compressed.

Patients with neck pain may relate most of the symptoms to a traumatic episode but more often, symptoms develop gradually. Pain may be limited to the neck, but occasionally referred pain will exist with complaints of discomfort of the shoulder, suboccipital area, and interscapular area. In addition, the patient has vague symptoms, such as blurred vision, tinnitus, or dysphagia. Often the discomfort is worse in the morning. Pain occurs during a period of driving or reading. There may often be an area of point tenderness in the surrounding musculature called a trigger point.

Cervical spondylosis or mechanical neck pain begin with degeneration of the cervical spine. Mechanical breakdown in the integrity of the disc makes it susceptible to the effects of minor trauma. Symptoms develop from episodes of trivial trauma and injury to the ligaments and joints of the spine. The instability may produce osteophyte formation causing compression of adjacent nerve and vascular or visceral structures or may produce an inflammatory response. Pain may often be reproduced by injection of a hypertonic saline solution into the symptomatic facet joint.

The patient must be questioned for symptoms of night pain, weight loss, and fever to help rule out non-spondylogenic pain. Physical examination often shows some restriction of spinal mobility. Neurological examination is normal in spite of pain referred to the upper extremities. Diagnostic study will often show signs of narrowing of the disc space with some degenerative spur formation. CT scan or MRI will show degenerative changes and possibly a central disc protrusion but without frank herniation.

The majority of patients with neck pain due to a degenerative process can be treated with a conscientious programme of non-operative treatment. The natural history of cervical disc disease is that of gradual resolution of symptoms in the majority of patients.

Reducing the mobility of the spine is useful in both the acute and chronic situation. It allows for healing of soft tissue and a decrease in the inflammatory reaction. Immobilization can be carried out in a number of ways including the use of a collar, bed rest, and traction. The most effective method is that of a soft cervical collar which controls the head in a neutral or slightly forward flexed position. Many collars actually place the neck in a somewhat extended position, aggravating pain from posterior facet articulation. The collar should not be worn for extended periods of time, as doing so leads to atrophy of paraspinal muscles. As soon as the pain begins to subside, neck exercises should be initiated. Traction is of little use.

Once pain begins to resolve, exercise is important. Two types of exercise are recommended: (1) isometric exercise to strengthen the paraspinal musculature, and (2) as pain decreases, range of motion programme to eliminate soft tissue contracture and loss of mobility.

In the vast majority of patients with neck pain symptoms will resolve over a period of weeks to months. Occasionally, the patient will fail to improve on a conservative regimen. Diagnostic studies will suggest a degenerative disc as the cause of pain. This may be confirmed by discometric analysis, that is, injecting the suspected disc with a small amount of saline, reproducing the patient's symptoms. In such cases, anterior discectomy and fusion may be indicated and has been shown to be highly effective in carefully selected cases.

When the degenerative process within the cervical spine causes compression or irritation of the cervical nerve root, the patient may experience not only neck pain but pain radiating to the shoulder, chest, arm, or hand. Nerve root compression may be brought about by herniation of disc material (so-called "soft disc") but more often is due to narrowing of the neuroforamen as a result of degenerative changes at the joint of Luschka and posterior facet.

The patient with cervical radiculopathy typically is in the fourth decade of life. Men are affected more frequently than women in a ratio of 1.4:1. Symptoms begin with either an acute or gradual development of pain or discomfort. Pain may involve the shoulder, chest, or arm and may be associated with a complaint of numbness and weakness. Often, no precipitating event can be identified.

Many patients present with arm and chest symptoms rather than neck pain. It may be considered that pain is cardiogenic and diagnostic studies to rule out angina are often performed. At other times, pain centring around the shoulder or elbow suggests a bursitis or tendinitis. Physical examination shows signs of a sensory deficit corresponding with specific dermatomal distribution. Motor examination shows a deficit sometimes even in the absence of pain or numbness. The differential diagnosis must include spinal cord tumour, brachial plescus, neuropathy, thoracic outlet syndrome, Pancoast tumour, and peripheral neuropathy. A careful history and physical examination is most helpful in ruling out these lesions but often diagnostic studies are necessary. Plain radiographs of the cervical spine are of little use. Oblique views of the cervical spine will show the neuroforamen and may in fact indicate an area of nerve root encroachment. The most nearly definitive test is MRI. This test has all but taken the place of the myelogram and CT scan in evaluating the cervical spine. Myelography may still be necessary, however, in patients who are claustrophobic or for other reasons cannot undergo MRI evaluation. Information from the myelogram may often be enhanced if this study is followed up with CT scan.

Just as with the patient with acute or chronic mechanical pain, the patient with cervical radiculopathy has a good overall prognosis for resolution of symptoms. Non-operative treatment makes use of immobilization, medication, and isometric exercises. Even the patient with frank neurological deficit can expect symptoms to resolve, especially after a short course of steroids given orally over a period of 5 to 7 days.

After failure of conservative measures consideration should be given to surgical treatment. There is little agreement among surgeons as to what is the best approach to the cervical spine in the patient with cervical radiculopathy, that is, whether to approach the spine from an anterior or posterior approach (Table 1) 618. The anterior approach is best for reaching the midline disc and if the patient is experiencing not only arm but also neck pain. The anterior approach provides a method of fusion to stabilize the involved segment. In a lesion affecting the nerve root peripherally at the foramen, a posterior approach may be favoured. This approach also allows the surgeon access to multiple roots if this is necessary.

As the degenerative process proceeds within the cervical spine, compression of the neural elements may include the spinal cord in addition to the cervical nerve roots.. When this occurs, the patient may be noted to have involvement of both the upper and lower extremities. The neurological pattern may show signs of lower motor neurone lesion in the upper extremities and upper motor neurone findings in the lower extremities. The patient may also develop bladder disturbances and may walk with a wide-based gait. Upper extremity findings may include weakness, and decreased sensation and reflexes while lower extremities will show evidence of weakness and clonus with hyper-reflexia and a positive Babinski reflex.

Two anatomical factors seem to play a role in the development of cervical spondylitic myelopathy. The first involves the blood supply to the spinal cord. Cervical cord is supplied from a large anterior spinal artery and two smaller dorsal lateral arteries. These vessels are fed by medullary feeders which enter the spinal canal through the foramen. Direct compression of the spinal artery by osteophyte or disc formation may impair blood supply. In addition, the medullary feeders may be compromised by narrowing of the foraminal opening in addition to the changes in circulation. The second factor which plays a role in cervical spondylitic myelopathy is that of narrowing of the spinal canal. This results from either protrusion of disc material or osteophyte formation anteriorly and buckling of the ligamentum flavum posteriorly. Myelopathy appears to be related both to mechanical compression and vascular compromise. Patients typically have preservation of the posterior column function (that is, of position, sense, and vibration with the majority of compromise in the anterior portion of the spinal cord). Demyelinization of the white matter develops, and MRI evaluation discloses not only narrowing of the spinal canal, but also changes within the substance of the spinal cord consistent with degeneration.

Patients will often describe difficulties in ambulation in addition to numbness and weakness in the upper extremities. Symptoms of bladder disturbance may also be present. Examination shows signs of sensory and motor deficit in the upper extremities and decreased reflex pattern, weakness, and hyper-reflexia in the lower extremities. Diagnostic studies typically include plain films which show presence of degenerative change and osteophyte formation. The most nearly definitive examination is MRI, as this gives the clearest picture of the size of the spinal canal and also the extent of spinal cord compression. MRI may also help prognostically by demonstrating degenerative changes within the spinal cord itself.

There is little place for non-operative treatment of patients with symptomatic cervical spondylitic myelopathy. The course tends to be progressive and as such, this information must be forwarded to the patient. As in cervical disc disease, there are two approaches to these patients. They include the anterior or posterior approach. If the patient tends to have the majority of compromise anteriorly, then this approach is favoured, especially if there is a tendency for the cervical spine to be in a somewhat straightened or kyphotic position. The spine that remains in the lordotic position often shows compromise posteriorly; in this case, the posterior approach provides adequate decompression. There are two types of posterior procedures: laminectomy and laminoplasty. Laminoplasty was originally developed for the treatment of ossification of the posterior longitudinal ligament as a method of enlarging the spinal canal. This method allows for reapproximating the posterior elements and thereby provides continued stability of the spinal column. Good to excellent results occur in 92 per cent of patients treated with anterior approach and in 86 per cent of those treated with laminoplasty. Only 66 per cent have satisfactory results following a standard posterior laminectomy.

Degenerative disease of lumbar spine

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