Arthrotic sciatica caused by radicular compression of osteophytic origin in the lateral recess. Apropos of 18 cases

The authors report 18 cases of arthrosic sciatica due to toot compression in the lateral recess by posterior corporeal and/or posterior apophyseal osteophytosis. The authors study the clinical and radiological characteristics that may indicate the diagnosis and discuss the different mechanisms by which vertebral arthrosis can lead to radicular compression. When surgery is necessary because of the persistent nature of the sciatica, a broader approach should be undertaken than that required for excision of the disc, in order to explore fully the roots, the multiplicity of possible compression sites being one of the essential characteristics of these cases of arthrosic radiculopathy. Study of the literature and of the series of sciatica patients operated upon by the authors shows that although discal hernia is far from being the most frequent cause of common sciatica, arthrosic compression is a cause that cannot be ignored, especially in aged subjects.     

Quality and accreditation in nephrology. The Italian perspective. Management and quality control

Three cases of extracranial vertebral artery dissections with upper limb peripheral motor deficit (C5-C6) are reported. Six similar cases were also found in the literature. Central neurological symptoms occurred in five of these nine cases, suggesting the diagnosis of dissection. The peripheral motor or sensorial deficit was strictly isolated in the four other cases, simulating radicular neuralgia due to discopathy or foraminal compression. In case of dissections, a precise analysis of pain is helpful to guide diagnosis; sharp, unbearable, continuous and extended neck pain without nocturnal paroxysms and posterior neck stiffness is typical. Analgesics or anti-inflammatory drugs are ineffective. Peripheral motor deficit is more common than sensory deficit. Recovery was complete in this series. In most cases, the radiculopathy appears to be due to cervical root compression in its extraforaminal course due to the dissection hematoma and rarely to radicular ischemia.     

Hypertrophied cauda equina presenting as intradural mass: case report and review of literature

BACKGROUND: Hereditary motor and sensory neuropathy types I and III usually lead to enlargement of peripheral nerves. Rarely, spinal nerve roots may also be involved, leading to radiculopathy and/or myelopathy. METHODS: This 44-year-old man with back and lower extremity radicular pain and distal lower extremity weakness and numbness was found to have a nonenhancing intradural mass that caused a nearly complete myelographic block from L1-L4. He underwent a decompressive laminectomy with intradural exploration. RESULTS: Hypertrophic but otherwise normal-looking nerve roots were observed. Subsequent electrodiagnostic testing and sural nerve biopsy confirmed that this patient had a previously unsuspected hereditary motor and sensory neuropathy (HMSN). His pain resolved, but at latest follow-up his weakness and numbness persisted. CONCLUSIONS: Nonenhancing spinal intradural mass lesions may represent enlarged nerve roots, which have a number of potential etiologies. Electrodiagnostic studies and peripheral nerve biopsy are instrumental in establishing the diagnosis of HMSN.     

Primary lymphoma of the liver with bile duct invasion and tumoral occlusion of the portal vein: report of a case

Vertebral artery tortuosity and loop formation are rare causes of cervical radiculopathy. The authors present the case of a 70-year-old man with 9 years of progressive right-sided cervical and scapular pain but no history of trauma. Computerized tomography myelography and magnetic resonance imaging revealed an ovoid mass in the right C3-4 intervertebral foramen. The patient underwent a right C-3 and C-4 hemilaminectomy and a complete C3-4 facetectomy. A pulsatile vascular structure was found compressing the right C-4 nerve root. The bone overlying the vascular structure was removed, producing decompression of the nerve root. Immediate postoperative angiography showed that this lesion was a focal vertebral artery loop. The patient's symptoms resolved after surgery, supporting the use of vascular decompression of a cervical nerve root compressed by a vertebral artery loop for the relief of radicular symptoms.     

Epidemiology, physical examination, and neurodiagnostics

The overall frequency of troublesome neck pain is estimated to be approximately 34%, and it was observed that the frequency of complaints lasting 1 month or longer was higher in women than in men. The prevalence increased with age with regard to both pain duration and chronic pain. A total of approximately 14% of a randomly selected population meets the criteria for chronic neck pain, with complaints lasting for more than 6 months. It could be that the structural transformation of the intervertebral disc, the uncovertebral processes, and the zygapophyseal joints is a process accompanied by disturbed function, ultimately inducing pain. For diagnosis of radicular and myelopathic syndromes, the physical and neurologic examination is enhanced by neurophysiologic assessment. Electromyography, performed with needle electrodes, is the oldest method to diagnose nerve root compression syndromes and is claimed to have no false positive results. Electromyography for radiculopathy is justified if clinical symptoms, such as muscular weakness, don't correlate with clinical findings (diminished or absent reflex), or for documentation of muscle activity if difficult decompressive surgery is expected. For diagnosis of cervical myelopathy by routine examination, the sensory evoked potentials by stimulation of tibial nerve as well as motor evoked potentials from upper and lower extremities are recommended because clinically "silent" myelopathy can be verified by abnormalities in evoked potentials. During history taking, the symptoms possibly attributed to radiculopathy or myelopathy should be differentiated from primary systemic neurologic disorders such as shoulder angiotrophy ("plexus neuritis"), multiple sclerosis, amyotrophic laterals sclerosis, and peripheral neuropathy. The assessment of range of motion, the functional status of shoulder and neck muscles, and palpatory examination of soft tissue is widely used to determine non-operative therapeutic procedures. However, scientifically, the validity of the different testing procedures has not been evaluated satisfactorily.     

The function of sensory nerve fibers in lumbar radiculopathy. Use of quantitative sensory testing in the exploration of different populations of nerve fibers and dermatomes

STUDY DESIGN: The function of sensory nerve fibers in patients with lumbar radiculopathy and in control individuals was evaluated using quantitative sensory testing. OBJECTIVES: To investigate the effect of lumbar nerve root compression on different populations of nerve fibers and to explore the function of sensory nerve fibers in neighboring nerve roots not involved in the mechanical compression. BACKGROUND DATA: Results from experimental and clinical studies indicate that chronic compression of lumbar nerve roots affects the large myelinated nerve fibers. The majority of nerve fibers involved in the sensation of pain, however, are small afferent nerve fibers. It is therefore of interest to study the effect of compression on large and small sensory afferent channels. Several authors have elucidated the biochemical interaction between disc tissue and nerve roots. Chemical substances in the epidural space can reach the nerve fibers in nerve roots at the same or neighboring lumbar segments. In this way, fibers not involved in the mechanical compression may be affected. METHODS: The small nerve fibers were studied using tests for thermal thresholds (thermotest), and the large myelinated fibers were studied by vibrametry. Forty-two patients were investigated in the symptomatic and the asymptomatic leg, and the results were compared with those of 21 healthy individuals. RESULTS: The thresholds of cold, warmth, and vibration were significantly increased in the dermatome of the compressed nerve root, indicating that large and small sensory nerve fibers were affected. Further, the thresholds were significantly increased in the neighboring dermatomes in the symptomatic and the asymptomatic leg. CONCLUSION: Large and small sensory afferent nerve fibers are affected in lumbar radiculopathy. The increase in sensation thresholds in the ipsilateral neighboring dermatome and in the dermatomes in the asymptomatic leg indicates that adjacent nerve roots are involved in the pathophysiology of sciatica in patients with lumbar disc herniation.     

Positions of dorsal root ganglia in the cervical spine. An anatomic and clinical study

STUDY DESIGN: The authors investigated the positions of dorsal root ganglia and the relation of the location to symptoms and to the effects of nerve root infiltration in the cervical spine anatomically and clinically. OBJECTIVES: To clarify normal variation of positions of dorsal root ganglia and the relation of the location of dorsal root ganglia to symptoms and to the effects of nerve root infiltration. SUMMARY OF BACKGROUND DATA: The dorsal root ganglia of the spinal nerve has attracted much attention as an important structure in the mechanisms of radicular symptoms in the lumbar spine. Although the position of the dorsal root ganglia in the lumbar spine has been classified recently, there are few reports regarding the dorsal root ganglia in the cervical spine. METHODS: The positions of dorsal root ganglia were divided into two types: proximally situated and distally situated. The positions of dorsal root ganglia in the anatomic and clinical cases were compared. The relation of the positions of dorsal root ganglia to symptoms and to the clinical effects of nerve root infiltration were analyzed. RESULTS: There was no statistically significant difference in positions of dorsal root ganglia in C6 nerve roots between anatomic and clinical cases. In addition, there was no relation between symptoms and the positions of dorsal root ganglia in clinical cases. However, there was a significant difference in positions of dorsal root ganglia in C7 nerve roots between anatomic and clinical cases. Nerve root infiltration was significantly more effective in the distally situated type of dorsal root ganglia. CONCLUSIONS: This study defined the normal variation of the positions of dorsal root ganglia. The results strongly suggest that some attention should be paid to the position of dorsal root ganglia in the diagnosis and treatment of cervical radiculopathy.     

A primary intrapelvic hydatid cyst presenting with foot drop and a gluteal swelling: a case report

A primary hydatid cyst in the pelvis is rare, and usually presents with pressure symptoms affecting the adjacent abdominal organs. We describe such a cyst which protruded through the sciatic notch and presented as a gluteal swelling with a foot drop due to compression of the lumbosacral nerve roots. Surgical excision and postoperative treatment with albendazole for six weeks were effective in controlling the disease and preventing recurrence.     

Clinical heterogeneity of adhalin deficiency

STUDY DESIGN: An assessment was made of the efficacy of a combined laminoplasty and foraminotomy operation for patients with coexisting myelopathy and unilateral radiculopathy. The procedure was done in 17 patients. OBJECTIVES: The patients were followed with lateral flexion and extension radiographs, computed tomography scans, and an assessment system specially designed to qualitatively evaluate the patients' neurologic status. Follow-up period averaged 4 years (range, 2.1-9.3 years). SUMMARY OF BACKGROUND DATA: Excellent-to-good results were obtained for 76% (13 of 17) of the patients without any significant functional compromise based on the radiographs. Sixteen nerve roots were decompressed with a less than 25% foraminotomy, whereas eight were decompressed by a 25%-50% foraminotomy without serious neurologic damage, except for one patient. The neurologic results appeared unrelated to the extent of foraminotomy. METHODS: A refined procedure for combined laminoplasty and foraminotomy was reviewed retrospectively in terms of neurologic outcome and radiographic data. RESULTS: The present series is small, and results are not comparable directly with other methods. The procedure appears effective for myelopathy and radiculopathy. This procedure is applicable to patients with myelopathy and coexisting nerve root impingement anterolaterally or in the neural foramen. CONCLUSION: The combined laminoplasty and foraminotomy operation may provide greater neurologic improvement in patients with coexisting myelopathy and unilateral radiculopathy, while maintaining cervical spine stability after surgery.     

Spinal cord decompression via microsurgical anterior foraminotomy for spondylotic cervical myelopathy

A microsurgical anterior foraminotomy, as a direct decompressive and motion-segment preserving technique, has been developed by the author and used successfully in many patients with spondylotic cervical radiculopathy for the past several years. From the author's increasing experience with anterior foraminotomy for cervical radiculopathy, it was noted that the spinal cord canal could be effectively decompressed utilizing the holes of anterior foraminotomy. This new technique accomplishes widening of the spinal cord canal anteriorly to the spinal cord in the transverse and longitudinal axis by direct removal of the compressive lesions through the holes of unilateral anterior foraminotomies. This technique does not require bone fusion or postoperative immobilization. 14 patients with spondylotic cervical myelopathy have been treated by this technique. 9 were males and 5 were females, and all presented with cervical myelopathy with or without radiculopathy. Age ranged from 32 to 68 years (median 55 years). 6 patients had spinal cord compression at one level, six patients experienced it at two levels, and two patients had it at three levels. Postoperatively, all patients showed improvement in their myelopathic symptomatology as well as gaining relief of their radicular symptoms. Corresponding MR scans confirmed satisfactory anatomical decompression in all patients. Postoperative dynamic roentgenograms confirmed spinal stability in all patients as well. Patients stayed in the hospital overnight postoperatively, and cervical braces were not used. This new surgical technique has shown excellent clinical outcomes with fast recovery and adequate anatomical decompression in 14 patients with spondylotic cervical myelopathy.     

Compression of the ulnar nerve at the wrist (author's transl)

Compressions of the ulnar nerve at the wrist in or beyond the canal de Guyon are comparative rare. Those originating from compression in the sulcus ulnaris at the elbow are much more common. The clinical symptoms are typical: Weakness of the small muscles of the hand, loss of sensibility and pain. The diagnosis can be made on the clinical picture. It has to be confirmed by electromyography. Surgery should be performed as early as possible to avoid permanent damage to the nerve. Any delay can cause irreversible loss of function of the ulnar nerve. As causes of the compression of the ulnar nerve tumours, inflammation of the sourrounding tissue or trauma have been described. In this paper we report about compression of the ulnar nerve in the canal de Guyon due to a thrombosed aneurysme of the ulnar artery. This condition is quite rare. It is characterized through sudden onset of pain in the hand. Immediate surgery with decompression of the nerve, as we did in our case, will result in complete recovery.     

Traction on the orthopedic table and pudendal nerve injury. Importance of electrophysiologic examination

PURPOSE OF THE STUDY: We performed a retrospective study about perioperative pudendal nerve palsy following fracture table tractions. MATERIAL: Six palsies were investigated. Mean age was 26 years. All of them presented sensitive and motor dysfunctions secondary to nerve compression following tractions on the fracture table. METHODS: All of them had complete electrophysiological recordings including perineal electromyogram, measurement of sacral roots latencies, sensory velocity of the dorsal nerve of the penis, somatosensory evoked potentials of the pudendal nerve and measurement of its terminal branches. RESULTS: Neurological symptoms were stereotyped associating sensory signs and sexual disorders, must of them being transient. Perineal electrophysiological examination always confirmed reality of pudendal nerve palsy. DISCUSSION: We discuss incidence, mechanism, etiology and prevention of this pudendal nerve palsy. CONCLUSION: Emergence of stereotyped perineal symptoms following orthopaedic surgery, especially after tractions on fracture table, must prevail on physicians to search for pudendal nerve palsy. Usual outcome is good in the six months following surgery, but definitive aftermath does occur. Perineal electrophysiological examination can confirm pudendal nerve palsy and give prognosis elements.     

Intraoperative electromyography during thoracolumbar spinal surgery

Intraoperative electromyography can provide useful information regarding lumbosacral nerve root function during thoracolumbar spinal surgery. Free-running electromyography provides continuous feedback regarding the location and potential for surgical injury to the lumbosacral nerve roots within the operative field. Stimulus-evoked electromyography can confirm that transpedicular instrumentation has been positioned correctly within the bony cortex. However, electromyography has a number of potential limitations, which are discussed in this article along with improved methods to increase the overall efficacy of intraoperative electromyography, including: 1) Electromyography is sensitive to blunt lumbosacral nerve root irritation or injury, but may provide misleading results with "clean" nerve root transection. 2) Electromyography must be recorded from muscles belonging to myotomes appropriate for the nerve roots considered at risk from surgery. 3) Electromyography can be effective only with careful monitoring and titration of pharmacologic neuromuscular junction blockade. 4) When transpedicular instrumentation is stimulated, an exposed nerve root should be stimulated directly as a positive control whenever possible. 5) Pedicle holes and screws should be stimulated with single shocks at low-stimulus intensities when pharmacologic neuromuscular blockade is excessive. 6) Chronically compressed nerve roots that have undergone axonotmesis (wallerian degeneration) have higher thresholds for activation from electrical and mechanical stimulation. 7) Hence, whenever axonotmetic nerve root injury is suspected, the stimulus thresholds for transpedicular holes and screws must be specifically compared with those required for the direct activation of the adjacent nerve root (and not published guideline threshold values).     

Clinical analysis of two-level compression of the cauda equina and the nerve roots in lumbar spinal canal stenosis

STUDY DESIGN: This study is a prospective, clinical study assessing the efficacy of selective decompression of the responsible level in two-level stenosis in accordance with neurologic findings defined by the gait load test, and functional diagnosis based on selective nerve root block. OBJECTIVE: To clarify the clinical features of two-level stenosis regarding the neurologic level responsible for the symptoms, neurogenic intermittent claudication, and the outcome of selective decompression. SUMMARY OF BACKGROUND DATA: Experimental studies have indicated that double-level compression of the cauda equina induces a more severe impairment of nerve function than does single-level compression. However, few studies have focused on the clinical importance of two-level stenosis. The clinical effects of two-level stenosis on the cauda equina and nerve roots are unknown. METHODS: A total of 81 patients with lumbar spinal canal stenosis due to spondylosis and degenerative spondylolisthesis were divided into two groups, two-level stenosis at L3-L4 and L4-L5, and one-level stenosis at L4-L5, based on myelography. The types of neurogenic intermittent claudication, the level responsible for neurologic findings, and the postsurgical outcome were compared between both groups. The level responsible for the symptoms in two-level stenosis was determined in accordance with neurologic findings on the gait load test and functional diagnosis based on a selective nerve root block. All patients underwent a prospective, selective decompression at the neurologically responsible level only. The average follow-up period was 4.6 years (range, 1-8 years). RESULTS: The patients with two-level stenosis more frequently had cauda equina symptoms than those with one-level stenosis, except patients with degenerative spondylolisthesis. It was therefore assumed that two-level stenosis was associated with cauda equina impairment, Changes in neurologic condition before and after the gait test were observed in four patients with two-level stenosis. Finally, for 28 patients with two-level stenosis, the levels responsible for the neurologic symptoms were the caudal level (L4-L5) in 22 patients, the cranial level (L3-L4) in 1 patient, and both cranial and caudal levels (L3-L4 and L4-L5) in 5 patients. All stenotic levels on the myelogram were not always symptomatic in two-level stenosis. However, in one-level stenosis, all of the responsible levels completely corresponded to the myelogram. Selective decompression only at the neurologically responsible level improved neurogenic intermittent claudication in all patients. The asymptomatic levels at which the stenotic condition was left unchanged at surgery did not become symptomatic at follow-up; in addition, there was no significant difference in the postoperative outcome between two-level stenosis and one-level stenosis. CONCLUSIONS: Two-level stenosis in patients with lumbar spondylosis is associated with production of cauda equina lesions. The gait load test provides information regarding changes in symptoms and neurologic condition during exercise. The responsible levels should be determined based on neurologic findings after the gait load test and a selective nerve root block. It is uncommon for both stenotic levels to be symptomatic in patients with two-level stenosis. Less invasive surgery such as selective decompression for the responsible level in patients with two-level stenosis is a useful technique with a good potential for long-term success.     

A cholera outbreak and control in a rural region of South Africa

Dance injuries associated with cervical radiculopathy have not been described in the literature. This report describes the case of an international-style ballroom dancer who developed a cervical radiculopathy as a result of frequent lateral rotation and hyperextension of the cervical spine during dancing. The patient's symptoms and signs suggestive of a left C7 radiculopathy were confirmed and documented by both magnetic resonance imaging and electrodiagnostic testing. The patient was treated conservatively with activity modification, nonsteroidal anti-inflammatory drugs, and alternative medicine approaches, including herbs and acupuncture. Her neck pain and cervical radicular symptoms declined in severity, but continued even 4 1/2 months after the onset of her symptoms. She did not wish to try steroids either through an oral or epidural route and refused surgical intervention. This case report illustrates an unconventional manner in which a left cervical radiculopathy was clinically produced. The neck motions and positions of frequent hyperextension and lateral rotation demonstrated by this ballroom dancer simulated a pattern and sequence of movements that promoted the development of signs and symptoms of a left cervical radiculopathy.     

Histologic analysis of the lumbosacral nerve roots after compression in young and aged rabbits

STUDY DESIGN: The histologic changes in the lumbosacral nerve roots of aged rabbits because of chronic (graded) and acute compression were compared with those seen in young rabbits. OBJECTIVES: To study differences in the process of recovery from nerve compression between the aged and the young. SUMMARY OF BACKGROUND DATA: Clinical findings often differ between nerve compressive lesions in young and aged patients. Little has been reported on the pathologic basis of this difference. METHODS: Forty-five Japanese white rabbits were used. The cauda equina and spinal nerve root were compressed with a device specifically designed for this purpose. Nerve compression was applied to the dura mater and nerve roots after partial laminectomy. The specimens were sampled at 1 month or 3 months after acute or graded nerve compression. RESULTS: An increase in small myelinated fibers, consistent with the process of regeneration, was observed by light microscopy; this difference was greater in the young group than in the aged group. Reactive degenerative changes, as seen by electron microscopy, were more often observed in the aged group than in the young group. CONCLUSIONS: These findings demonstrate the suppression of regeneration and the latent fragility of the aged neural tissue. This may explain the clinical findings observed in aged patients with degenerative lumbar lesions.     

The effect of epidural injection of betamethasone or bupivacaine in a rat model of lumbar radiculopathy

STUDY DESIGN: The effect of epidural injection of betamethasone or bupivacaine was investigated in an animal model of lumbar radiculopathy. OBJECTIVE: To investigate the effects of an epidural steroid (betamethasone) or a local anesthetic (bupivacaine) in an animal model of radiculopathy produced by nerve root irritation. SUMMARY OF BACKGROUND DATA: Epidural injections are commonly used for the treatment of low back pain and sciatica. However, efficacy remains controversial, and there is a paucity of basic information to support clinical use or the injections. METHODS: Fifty-one rats were used. The left L4 and L5 nerve roots were loosely ligated with chromic gut, and either betamethasone, bupivacaine, betamethasone in combination with bupivacaine, or saline was injected using an epidurally placed catheter. The effects of epidural injection were evaluated using response to noxious stimuli and immunohistochemical methods. RESULTS: In betamethasone-treated rats (either alone or in combination with bupivacaine), thermal hyperalgesia was significantly less (P < 0.010 after surgery than that in saline- or bupivacaine-treated groups, in which the hyperalgesia was maximum at 2-3 postoperative weeks before resolving 5 weeks after surgery. Immunohistochemical analysis did not correlate with these results. CONCLUSIONS: Epidural steroid injection has a significant effect on the thermal hyperalgesia produced in a model of radiculopathy, which may provide clinical support for advocates of epidural steroids.     

The posterior operative approach for cervical radiculopathy

Cervical disc disease includes acute herniation and chronic disc degeneration with secondary changes in the associated bone. The latter may lead to the spectrum of cervical spondylitic stenosis, which is considered to be multilevel and may be more of a bony disease. Clinically, cervical disc disorders can be divided into several disorders. The disorder of true cervical radiculopathy is associated with lateral compression of the nerve root. When this condition is due to a lateral soft disc herniation or lateral bony stenosis, the posterior cervical laminoforaminotomy is commonly used. It is a procedure that works extremely well in the vast majority of patients and there is no risk of spinal instability; therefore, no fusion is required. The details of operative care have been described. In patients who have persistent radicular problems after a failed anterior cervical interspace procedure, the posterior cervical laminoforaminotomy with posterior wiring and fusion is a simple and effective operative option.     

Causes of failure of surgery on the lumbar spine

An interinstitutional study on the failed back surgery syndrome (FBSS) has determined that failure to recognize or adequately treat lateral stenosis of the lumbar spine with resultant nerve irritation and/or compression comprised the primary etiology in 57% to 58% of patients. Other common causes were recurrent or persistent disk herniation and lumbosacral adhesive arachnoiditis. The diagnosis of stenosis was made either by high-resolution CT scan of the lumbar spine or by directly testing lateral canal and for animal patency at the time of surgery. It is now appreciated that the process of degenerative disk disease, particularly when enhanced by diskectomy, results in progressive loss of intervertebral disk volume and predisposes to future ipsilateral or contralateral lateral spinal stenosis. Degenerative disk disease is ultimately a bilateral process and therefore surgical exposure should be bilateral. The direct and indirect costs of FBSS to patients and to society as well as the toll in human suffering are very high. This is particularly a matter of concern when it is realized that for many FBSS patients, surgery could have been avoided in the first place by preventive care or by innovative conservative treatment. When surgery is indicated, adequate diagnostic tests and the execution of appropriate procedures based upon this information should largely prevent the failed back surgery syndrome.     

The antero-posterior diameter of the cervical spinal canal in cervical spondylosis (author's transl)

1. The antero-posterior diameter (APD) of the cervical spinal canals in 96 healthy adults, 108 cases of radiological cervical spondylosis (asymptomatic) and 96 cases of cervical spondylosis with radiculopathy or radiculomyelopathy was measured for each vertebra by the method of Burrows. (Filmfocus distance was 1.2m). 2. The APD in patients with symptomatic spondylosis was found to be significantly narrower than those of without. 3. Since the upper limit of APD at C4 to C6 vertebrae in symptomatic spondylosis was 16 mm, while the lower limit of APD in asymtomatic spondylosis was 14 mm, the following conclusion appears justified. 1) When the APD is narrower than 16 mm, the osteophytes along the posterior border of the spinal bodies or degenerative disc protrusions may produce cervical radiculomyelopathy, although the cord and the roots may escape from compression by the spondylotic changes even when the APD is wider than 14 mm. 2) When the APD is narrower than 13 mm, it is almost always certain that the osteophytes or herniated discs compress the cervical cord and roots.