Spinal stenosis and health status

STUDY DESIGN

This study examined the hypothesis that a small adult vertebral canal is a marker of early impairment of growth, and that other sensitive systems may be impaired similarly, producing an adult relationship among a small canal, poor health, and academic ability.

OBJECTIVES

Comparisons of health and some aspects of academic ability were made between patients whose canals were above and those below the mean at L5.

METHODS

Seventy-five patients were examined, 42 men and 33 women. They had comprehensive cardiovascular, respiratory, and digestive system health assessments. Their post-school qualifications were recorded, and they were assessed by the Mill Hill vocabulary test and the progressive matrices test.

RESULTS

Twenty-two men and 21 women had canals above the mean, and 20 men and 12 women had canals below the mean. A significant difference did not exist in the age of those with wider and narrower canals. Cardiovascular symptoms and gastrointestinal symptoms were more common in men and women with narrower canals (P = 0.04 and 0.048), but there was no significant differences in respiratory symptoms. Those with wider canals had more post-school qualifications than those with smaller canals (P = 0.04), and in men, their performance in the Mill Hill vocabulary test and the progressive matrices test approached significance (P = 0.08 and 0.06).

CONCLUSIONS

The association between a smaller vertebral canal and impairment of health and certain intellectual abilities may result from an adverse environment that affects several growing systems early in life. If the small canal is a marker of a generalized developmental disturbance, it is, to some degree, preventable.

Cervical spine surgery and handwriting: a case report

The 53-year-old right-handed woman underwent decompressive laminectomies and foraminotomies at the C3-C7 levels. The course of illness and postoperative recovery were documented by handwriting and MRI views, but not statistical analysis.

Up and down the spinal cord: intraoperative monitoring of sensory and motor spinal cord pathways

Monitoring of spinal cord function during certain orthopedic and neurosurgical procedures is done to reduce the likelihood of neurologic complications. This article is based on intraoperative experiences gained at Duke University Medical Center since 1978. Both ascending sensory (up) and descending motor (down) data can be evaluated to assist in improved patient outcomes. Refinements in technique and better understanding of the neural generators of evoked potentials obligate the components to have improved sensitivity and specificity of spinal intraoperative monitoring. An additional improvement has been the intraoperative use of motor evoked potentials. This discussion deals with a description of specific responses obtained following lower-limb mixed nerve stimulation in terms of neural generation, influences of rate and intensity, and anesthetic effects. The techniques and advantages of bipolar epidural recording and stimulation are discussed. Motor tract stimulation via the same epidural electrodes used for recording of sensory components is described. Case reports are presented to emphasize major points.

Spear tackler's spine. An entity precluding participation in tackle football and collision activities that expose the cervical spine to axial energy inputs

We describe spear tackler's spine, a clinical entity that constitutes an absolute contraindication to participation in tackle football and other collision activities that expose the cervical spine to axial energy inputs. A subset of football players were identified who demonstrated: 1) developmental narrowing (stenosis) of the cervical canal; 2) persistent straightening or reversal of the normal cervical lordotic curve on erect lateral roentgenograms obtained in the neutral position; 3) concomitant preexisting posttraumatic roentgenographic abnormalities of the cervical spine; and 4) documentation of having employed spear tackling techniques. From data obtained by the National Football Head and Neck Injury Registry and the senior author's practice, 15 cases of spear tackler's spine were identified during 1987 to 1990. All 15 cases were evaluated because of complaints referable to the cervical spine or brachial plexus resulting from football injuries. Of these, 11 had complete neurologic recovery without permanent sequelae. Four cases resulted in permanent neurologic deficits: quadriplegia, 2; incomplete hemiplegia, 1; and residual long track signs, 1. Permanent neurologic injury occurred as the result of axial loading of a persistently straightened cervical spine from use of head-impact playing techniques. We suggest that individuals who possess the aforementioned characteristics of spear tackler's spine be precluded from participation in collision activities that expose the cervical spine to axial energy inputs.

[Lumbar spinal stenosis. An overview 50 years following initial description]

About 50 years after the first descriptions of lumbar stenosis and its most frequent symptom, neurogenic intermittent claudication, this update gives an overview of present-day concepts of the disease and of new experience in this area. Stenosis of the central and lateral lumbar spine is chiefly held to be one of the results of segmental degenerative instability throughout the several stages of spondylosis. The degenerative process of the spine has its starting point in regressive changes of the disc. This leads to instability of the motion segment, which explains the pathophysiological dynamics of the stenosis and its symptoms, including intermittent neurogenic claudication. Segmental instability is the crucial lesion causing all the changes in the degenerative process, which are not to be considered as separate entities but as part of the dynamics of the same disease. The spine's congenital anatomic individual patterns, which confirm the population thinking of the evolutionary biology (since they are different from one motion segment to the other) help to determine the outline of single cases. The disparity between radiological and clinical patterns is pointed out: severe stenosis may be asymptomatic or cause just modest monoradicular trouble as well as serious multiradicular deficit. The reason for the discrepancy is unknown. One must be careful to avoid surgery on a silent, purely radiological stenosis. Experience of more than 15 years confirms the uselessness of performing a complete laminectomy to achieve sufficient decompression. The author's method of selective decompression is described briefly. The English term "undercutting decompression" runs the risk of being misunderstood, since it is also used for rather destroying procedures. Finally, we point out that surgery for spinal stenosis must resolve both root compression and degenerative instability in the majority of cases. In most cases of lumbar stenosis, if decompression alone is performed, only the consequence, and not the cause of the disease, segmental degenerative instability, is treated. Osteophyte formation is an attempt by nature to stabilize the motion segments by stiffening its components. Spinal fusion tries to achieve the same effect. For most cases of spinal stenosis, we suggest our own technique, which combines safe and preserving ("selective") decompression according to Benini [1,7] with the translaminar screw fixation of Magerl [7]. In cases of degenerative spondylolisthesis, however, transpeduncular fusion is mandatory.

[Spinal stenosis. A review]

Spinal stenosis is characterized by a broad spectrum of symptoms which are often vague. Therefore, patients suffering from this condition are typically seen by various specialists over a long period of time. Among the symptoms are various degrees of low back pain, neurogenic claudication, parasthesias, muscle weakness and reflex abnormalities. When spinal stenosis is suspected, CT-scanning seems to visualise stenosis well. Because the localisation of the stenosis is often unknown, myelography is still the first choice. CT-scanning can then provide supplementary information regarding the specific location. MR-scanning is not as yet used as a routine procedure, but will in time replace both procedures. Conservative treatment consisting in analgesics and physiotherapy is sufficient in some cases. When conservative treatment is not enough, surgical intervention consisting in decompression by broad laminectomy is performed. Fusion is performed when there are signs of vertebral instability or in young patients. Operational results are often good. Failure is seen following insufficient decompression.

Lumbar spinal stenosis: clinical/radiologic therapeutic evaluation in 145 patients. Conservative treatment or surgical intervention?

In this prospective study, 145 patients with lumbar spinal stenosis were evaluated for clinical signs and radiologic findings and conservative treatment results. Clinical parameters such as pain on motion, lumbar range of motion, straight leg raising test, deep tendon reflexes, dermatomal sensations, motor functions and neurogenic claudication distances were assessed at admission and were compared after a conservative treatment program was completed. A conservative treatment program consisted of physical therapy (infrared heating, ultrasonic diathermy and active lumbar exercises) and salmon calcitonin. Pain on motion (100%), restriction of extension (77%), limited straight leg raising test (23%), neurogenic claudication (100%), dermatomal sensory impairment (47%), motor deficit (29%), and reflex deficit (40%) were observed in the patients. All aforementioned disturbances except reflex deficits improved by the conservative treatment and results were statistically significant. The authors conclude that this conservative treatment should be the treatment of choice in elderly patients and in those patients without clinical surgical indications.

Somato-sensory evoked potentials in root lesions and stenosis of the spinal canal (their diagnostic significance in clinical decision making)

The aim of the present study was to determine the significance of different SEP techniques and parameters in clinical evaluation of cases of lumbar and cervical root lesions and stenosis of the spinal canal. Using a qualitative rating scale, 92 cases were analyzed retrospectively whose primary diagnosis was questioned because of conflicting data from clinical, neuroradiological and neurophysiological testing. In conclusion SEP techniques proved to be a useful tool in exclusing other e.g. demyelinating diseases. Except for the time-consuming method of segmental stimulation, the demonstration of the functional deficit itself by SEP techniques in general was frequently disappointing. The contribution of the different SEP parameters to clinical decision making and the clinical consequences are briefly discussed.

Long-term evaluation of decompressive surgery for degenerative lumbar stenosis

One-hundred patients who had undergone decompressive surgery for lumbar stenosis between 1980 and 1985 were evaluated as to their long-term outcome. Four patients with postfusion stenosis were included. A 5-year follow-up period was achieved in 88 patients. The mean age was 67 years, and 80% were over 60 years of age. There was a high incidence of coexisting medical diseases, but the principal disability was lumbar stenosis with neurological involvement. Results were categorized as either a surgical success or a failure, depending upon the achievement of preset goals within the context of lifestyle and needs. There were no perioperative complications. Initially there was a high incidence of success, but recurrence of neurological involvement and persistence of low-back pain led to an increasing number of failures. By 5 years this number had reached 27% of the available population pool, suggesting that the failure rate could reach 50% within the projected life expectancies of most patients. Of the 26 failures, 16 were secondary to renewed neurological involvement, which occurred at new levels of stenosis in eight and recurrence of stenosis at operative levels in eight. Reoperation was successful in 12 of these 16 patients, but two required a third operation. The incidence of spondylolisthesis at 5 years was higher in the surgical failures (12 of 26 patients) than in the surgical successes (16 of 64). Spondylolisthetic stenosis tended to recur within a few years following decompression. To forestall recurrences, it is suggested that stabilization be carried out at levels of spondylolisthetic stenosis and the initial decompression include adjacent levels of threatening symptomatic stenosis. However, the heterogenicity of this patient population, with varying patterns and levels of symptomatic stenosis, precludes application of rigid surgical protocols.

Hydrocephalus, lumbar canal stenosis and Maroteaux-Lamy syndrome (mucopolysaccharidosis type 6). Case report

A case of communicating hydrocephalus and lumbar canal stenosis in a child with mucopolysaccharidosis type 6 is reported. We review the literature and discuss the aetiology of communicating hydrocephalus in this condition.

Magnetic resonance imaging in the evaluation of cerebrospinal fluid flow abnormalities

Phase contrast magnetic resonance imaging techniques can be used to evaluate the to-and-fro motion of cerebrospinal fluid (CSF) throughout the ventricles and subarachnoid space of the brain and spine. This CSF motion is due to transmitted cardiac pulsations from systolic expansion of the cerebral hemispheres. To cover the entire cardiac cycle, retrospective cardiac gating (rather than electrocardiographic triggering) must be used. Using this technique, it is possible to quantify CSF motion over a cardiac cycle and to distinguish normal aqueductal CSF "stroke volumes" from those seen in atrophy and shunt-responsive communicating hydrocephalus. Arachnoid cysts and other loculated CSF collections can be diagnosed using a "rebound sign" in which the motion of the CSF within the cyst is 90 degrees phase advanced over the CSF flowing around it.

Voiding dysfunction and urodynamic findings in patients with cervical spondylotic spinal stenosis compared with severity of the disease

A group of 30 consecutive patients (26 men and 4 women, mean age 51 years), with clinically and radiologically verified cervical spondylosis causing radiculopathy and/or myelopathy, were questioned about voiding symptoms, examined urodynamically and subjected to tests of tibial somatosensory evoked potentials (SEP). Seventeen patients (61%) complained of irritative bladder symptoms and detrusor hyperactivity was demonstrated urodynamically in 13 (46%). Three (11%) experienced difficulty in emptying the bladder, and all of these had a hypotonic detrusor. The bladder was insensitive to cold in 36%, this and SEP abnormalities being more common in the patients with clinically severe myelopathy, whereas detrusor hyperactivity was found equally in all patients. Urodynamic investigation seems to provide additional information on the severity of the disease and is therefore recommended for wider use in these patients.

The natural course of lumbar spinal stenosis

The course of 32 untreated patients with spinal stenosis was studied. The mean patient age was 60 years, and the mean period of observation was 49 months. About 75% of the patients had spinal claudication. In the follow-up survey, the same number of patients had claudication, but the symptoms were milder. In estimation by visual analog scale, symptoms in 70% of the cases were unchanged, 15% showed improvement, and 15% worsened. No proof of severe deterioration was found after four years, and expectant observation may be an alternative to surgical treatment.

[Sciatica or herniated disk]

Lumbar radiculalgia may be due, beside the disc-nerve root conflict, to stenosis of osteoarticular canals, wide dural sac, epidural lipomatosis, segmental arachnoiditis, malignant or benign tumours and meningoradiculitis. Extraspinal truncular or radicular sciatica is usually due to compression by an expansive process. Some types of pain referred from articular structures may mimic sciatica.

Paget disease of the spine

Seventy patients who had the radiographic features of Paget disease of the spine were evaluated clinically and with computed tomography, with the objective of correlation of the symptoms with the lesions. Of forty-five symptomatic patients, twenty-one had only pain in the back or neck and twenty-four patients had spinal stenosis with or without pain in the back or neck. Seven patients had a neurological deficit without pain, nineteen had so-called mechanical or arthritic pain, nine had pain that was attributable to the Paget lesion, and ten had a combination of the two types of pain. The most common cause of the spinal stenosis was expansion of bone that led to compression of the thecal sac and its neural elements. In one patient, the cord was compromised further by a pathological fracture of the eighth thoracic vertebra. There was a strong correlation between the presence of symptoms and the findings of spinal stenosis and arthropathy of the facets (zygapophyseal joints) on computed tomography. The spinal stenosis and the arthropathy of the facets were caused by the abnormal, hyperactive bone-remodeling, which resulted in the expansion of the osseous elements of the involved vertebra or vertebrae.

Long-term roentgenographic and functional changes in patients who were treated with wide fenestration for central lumbar stenosis

Thirty-four patients who had central stenosis of the lumbar spine were treated with wide fenestration, a procedure in which only the medial parts of the inferior facets and the adjoining ligamentum flavum were removed. The patients were followed for an average of five and one-half years (range, four and one-half years to seven years and ten months). Wide fenestration successfully relieved the symptoms. The new bone that was laid down in the operatively treated segments did not reproduce the symptoms of spinal stenosis; instead, it appeared to stabilize those segments.

Magnetic stimulation: examination of motor function in patients with cervical spine or cord lesion

In 20 patients with cervical spine or cord lesions, we examined motor evoked potentials (MEPs) by transcranially applied magnetic stimulation to the motor cortex. We used a large-diameter (12 cm) coil to induce equal current in both left and right hemispheres. The MEPs were recorded simultaneously from multiple muscles covering the C5 to C8 myotome distribution bilaterally. The MEP abnormalities correlated well with clinical muscle weakness in 15 patients. In two patients, MEP revealed abnormalities in muscles of normal strength. Three patients with sensory but without motor deficit had normal MEPs. We conclude that magnetic stimulation is a useful adjunct in confirming and objectifying motor weakness, and in localizing the level of dysfunction in cervical spine lesions.

Dynamic F waves in neurogenic claudication

Serial F waves were elicited before and after ambulation in 2 patients with neurogenic claudication. In both patients dynamic changes in F wave parameters consisting of either unelicitability or increased latencies occurred postexercise. The time course of these changes and their subsequent rapid reversibility over 15 minutes suggest ischemic-induced conduction block and slowing in proximal motor axons. These physiological changes may account for some of the dynamic neurological symptoms of this disorder. Moreover, F wave exercise testing may provide corroborative information for the diagnosis of neurogenic claudication.

The significance of venous return impairment in ischemic radiculopathy and myelopathy

Because much of the symptomatology consequent to the constrictive lesions of spinal degenerations may be the result of radicular neurischemia, medullary neurischemia, or both, the structure and responses of the nerve root vasculature to compression or tension are discussed. Although the original investigations concentrated on the arterial side of the radiculomedullary circulation, more recent research has indicated that the venous return phase is far more susceptible to the effects of both intraspinal and extraspinal pathologic conditions.

Acquired cervical spine impairment in young adults with cerebral palsy

Three patients with spastic cerebral palsy and no associated movement disorder--each of whom presented with loss of functional skills and delay in the definitive diagnosis of cervical myelopathy--are reported, in order to increase awareness of the possibility of cervical spine pathology in these adults. The possibility of myelopathy should be investigated when considering the etiology of functional deterioration. A functional neurological examination for all multiply disabled individuals is proposed as a reference for future comparison.

[The potential role of transcranial magnetic stimulation in the diagnosis of lumbosacral radiculopathies]

We were interested in the question, if transcranial magnetic stimulation of nerve structures can be used in the objective description of motor impairment in humans with lumbosacral radiculopathies. We could demonstrate, that severe clinical motor deficit and changes of evoked muscle potentials correlate to a high degree. In contrast to electrical stimulation, magnetic impulses are not painful and offer the advantage of a selective activation of motor systems. Applications of the method in Orthopaedics involve perioperative control of motor capacity, description of radicular motor damage and the diagnosis of peripheral nerve lesions. Although the value of the method for orthopaedic purposes is not yet clear, our experiences indicates interesting diagnostic possibilities.

MR phase imaging and cerebrospinal fluid flow in the head and spine

Motion of the cerebrospinal fluid (CSF) in and around the brain and spinal cord was examined in healthy subjects and in a number of patients with abnormalities of the CSF circulation. The pulsatile motion of the CSF was determined by spin echo phase (velocity) imaging, sometimes in combination with gradient echo phase contrast cine. Differences in flow patterns across CSF spaces were observed: flow reversal in the cerebellomedullary cistern and lumbar area relative to cervical CSF, and in the posterior versus the anterior subarachnoid space in the spinal canal. Flow communication was demonstrated in known communicating cysts or cavities. Differences in flow were also noted across spinal narrowing or block, and across the walls of a variety of cystic lesions in the brain and spinal cord. MR phase imaging of CSF flow provides pathophysiological information of potential clinical importance for the assessment of diseases affecting the CSF circulation.

[Erection while walking and stenosis of the lumbar canal]

Lumbar channel stenosis is frequently manifested by a Cauda Equina intermittent claudication. Only exceptionally erections during walking have been described. We have observed two patients with severe lumbar channel stenosis and a Cauda Equina syndrome with intermittent erections during walking. One patient was laminectomized presenting a clinical improvement. There does not exist a satisfactory explanation for this strange affectation.

Experimental lumbar spinal stenosis. Analysis of the cortical evoked potentials, microvasculature, and histopathology

An animal model of lumbar spinal stenosis was developed in which the pathophysiology of this condition could be examined. Four experimental groups, each containing six dogs, were studied. One group had a laminectomy of the sixth and seventh lumbar vertebrae only; these animals served as controls. In the three other groups, a laminectomy was performed and the cauda equina was constricted by 25, 50, or 75 per cent to produce chronic compression. Cortical evoked potentials were recorded preoperatively, immediately after constriction, and at one, two, and three months postoperatively. Daily neurological examinations were carried out, and the neurological deficits were graded using the Tarlov system. After three months of constriction, the cauda equina of three dogs in each group was examined histologically, and the vascular circulation was examined by latex and India-ink injection with a modification of the Spalteholz technique. The animals in the control group showed no neurological abnormalities, no changes in cortical evoked potentials, normal microvascularity, and no histopathological changes in the nerve roots or the spinal cord. The dogs in which the cauda equina had been constricted 25 per cent had no neurological deficits, mild changes in cortical evoked potentials, slight histological changes, and venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 50 per cent had mild initial motor weakness, major changes in cortical evoked potentials, edema and loss of myelin in the root of the seventh lumbar nerve, and moderate or severe venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 75 per cent had significant weakness, paralysis of the tail, and urinary incontinence; two dogs recovered by the third month, but all had neurogenic claudication for three months. All six dogs had dramatic changes in cortical evoked potentials and had complete nerve-root atrophy at the level of the constriction. There was blockage of axoplasmic flow and wallerian degeneration of the motor nerve roots distal to the constriction and of the sensory roots proximal to the constriction, as well as degeneration of the posterior column. Severe arterial narrowing at the level of the constriction and venous congestion of the roots and dorsal root ganglia of the seventh lumbar and first sacral nerves were also present. Cortical evoked potentials revealed neurological abnormalities before the appearance of neurological signs and symptoms.(ABSTRACT TRUNCATED AT 400 WORDS)

[Clinical and experimental studies on ascending cauda equina action potential (A-CEAP) in lumbar lesion with reference to positivisation]

The phenomenon of positivisation in ascending cauda equina action potential (A-CEAP) was evaluated in 114 patients with lumbosacral lesions. These patients were divided into two groups, i.e., non-positivisation and positivisation group. In the former, positive wave ratio was highest at the L5/S upon stimulating the peroneal nerve. In the latter, the positivisation at the L4/5 upon stimulating the peroneal nerve spread not only to the cranial level but also to the caudal-L5/S level. Based on these experimental results, the factors causing positivisation in the L5/S level without lesion were: 1) curving effect of the L5 nerve root, 2) augmentation of current density within the spinal canal and 3) the amount of individual impulses propagating along the L5 and S1 root.

Functional deficits of central sensory and motor pathways in patients with cervical spinal stenosis: a study of SEPs and EMG responses to non-invasive brain stimulation

The central conduction time of the descending and ascending fibers of the spinal cord were examined in patients with radiologically defined cervical spinal stenosis (antero-posterior diameter of the spinal canal less than 13 mm). Nineteen patients were examined, only 4 of whom showed clinical signs of spastic weakness or ataxia. The electromyographic response after non-invasive stimulation of the leg area of the motor cortex was delayed in 13 of the 15 clinically unaffected patients. The central latency (N21-P39) of the somatosensory evoked response after stimulation of the tibial nerve (tibialis SEP) was increased in 12 of the 15 individuals. The 4 patients with clinical signs showed abnormal latencies with both methods. The use of both techniques for the examination of the function of the spinal cord revealed increased latencies in the central motor and/or sensory pathways in all patients. The technique of non-invasive stimulation of the corticospinal system therefore provides an additional tool to detect and quantify subclinical and clinically apparent lesions in patients with defined cervical spinal stenosis.

Spinal claudication in systemic amyloidosis

We describe a patient with hereditary amyloidosis who developed the syndrome of spinal claudication. Myelography and computerized tomography of the lumbar spine demonstrated stenosis of the spinal canal and surgical exploration confirmed dense amyloid infiltration of ligamentous structures compressing the nerve roots. Two cousins of our patient and 2 patients with immunoglobulin amyloidosis had similar clinical syndromes. Spinal stenosis can be demonstrated by myelography or by computerized tomography. Diagnosis of this syndrome is important since wide decompression may be needed to relieve symptoms. Patients who had only disc extraction did not improve after the operation; their symptoms persisted and even worsened.

Magnetic stimulation in the diagnosis of lumbosacral radiculopathy

Five patients presenting with sensory-motor disturbances consistent with a clinical diagnosis of L5 or S1 radiculopathy were studied. All had conventional nerve conduction tests and electromyography. The lumbosacral roots were stimulated in the lumbosacral region by using the Cadwell MES-10 Magneto-electric stimulator. The compound muscle action potentials were recorded bilaterally by surface electrodes applied to the soleus and tibialis anterior muscles. The latencies to the affected muscles were significantly prolonged. The appropriate root dysfunction was confirmed at operation or by the imaging techniques. It was concluded that surface stimulation of the lumbosacral roots by a magnetic coil is a potentially useful technique for the non-invasive evaluation of the function of the lumbosacral roots.

Preoperative and postoperative instability in lumbar spinal stenosis

Sixty-one patients operated on for spinal stenosis, without a fusion, were studied retrospectively. Preoperative instability, as revealed by functional myelography, was found to predict a poor prognosis (P less than 0.01). Women had less favorable results (P less than 0.05). The "slipping" group was significantly more often radically decompressed than the "nonslipping" group (P less than 0.01). Postoperative slipping was found in 26 patients, significantly more often in those with unsatisfactory results (P less than 0.001).

[Function of the long spinal cord pathways in cervical spinal stenosis--an electrophysiologic study]

Cervical spinal stenosis is radiologically defined by a reduced inner diameter (X less than 13 mm) of the cord canal and in most cases etiologically connected with spondylosis. The following study describes the results of non-invasive assessment of the long ascending and descending spinal tracts in 12 patients. The long ascending spinal tracts were examined by spinal and cortical SEP after stimulation of the tibial nerve; for the assessment of the descending spinal tracts motor responses of the tibial anterior muscle were recorded after non-invasive stimulation of the motor cortex. Clinically symptomatic patients (N = 2) exhibited clear-cut functional motor and sensory deficits of the central pathways. In asymptomatic patients (N = 10) corticomotoneuronal latencies to the lower limbs were increased in 8 cases. In comparison, increased central sensory latencies were found in 9/10. In conclusion, the studies showed that the technique of non-invasive stimulation of the motor cortex may play a role in the detection of subclinical lesions of the long descending motor tracts due to a chronic mechanical irritation.

Urodynamic evaluation of patients with spinal stenosis

Spinal stenosis, which may be congenital/developmental or acquired in origin, is a narrowing of the spinal canal, nerve root canals, or intervertebral foramina. Compression of the spinal cord or nerve roots may lead to structural neuronal damage, neuronal ischemia or edema, and axonal transport block. The most frequent symptom in patients with spinal stenosis is back pain and some have classic neurogenic claudication. We have performed urodynamic evaluations in 2 patients with combined cervical and lumbar spinal stenosis. A girl with achondroplastic dwarfism had urgency incontinence and detrusor hyperreflexia. An adult man with acquired degenerative spinal stenosis had difficulty voiding and findings compatible with the cauda equina syndrome.

Sway of the center of gravity in patients with spinal canal stenosis

In this study the sway of the center of gravity was observed in patients with spinal canal stenosis, in order to observe the movement of the center of the gravity after the onset of claudication. In normal subjects the sway of the center of gravity was restricted to a small area, but in patients with spinal stenosis, the center of gravity was diverted to the left or right side. With claudication, the center of gravity moved forward. Following several rest periods, the center of gravity returned to the initial area. The time required to return to the initial area was longer than for a patient's subjective recovery from the symptoms.

[Venous pressure in the vertebral venous plexus and its role in cauda equina claudication]

The venous pressure in the ascending lumbar vein was measured by catheter and pressure transducer to document venous stasis in degenerative lumbar spinal canal stenosis. Measurement of the pressure in the ascending lumbar vein at rest revealed a progressive rise of the mean pressure from the control group to the lumbar intervertebral disc herniation group, and the lumbar spinal canal stenosis (LSCS) group in ascending order. Pressure curve tracings showed a plateau accompanying increased abdominal pressure during the Valsalva maneuver. Phase 3 was defined as the recovery period of decreasing pressure which began with the release of abdominal compression and terminated with the return to the initial pressure. The duration of phase 3 was prolonged in LSCS (p less than 0.01). It followed that the prolonged phase 3 documented the existence of venous stasis and its extent in LSCS. It is conceivable that increased venous pressure in the lumbar vertebral venous plexus participates in the pathogenesis of cauda equina claudication in LSCS.

Posterior central cord syndrome following a hyperextension injury: case report

Throughout the spinal cord literature, a posterior central cord syndrome has been noted to be a rare occurrence. Furthermore, it has never been correlated with a specific type of injury. A patient with clinical signs consistent with a posterior central cord syndrome is discussed, and hyperextension is suggested as a possible mechanism for this type of injury.

Pressure changes following constriction of the cauda equina. An experimental study in situ

During routine autopsies in 11 cadavers, the intact dural sac, including its nerve roots, was circumferentially constricted by a clamp while the pressure under the clamp among the nerve roots was recorded simultaneously. The first sign of a pressure increase--the critical size--occurred at a cross-sectional area of the cauda equina of 77 +/- 13 mm2. To achieve a pressure increase of 50 mm Hg, the cross-sectional area of the cauda equina had to be further constricted at an average of 19 +/- 8%. The corresponding constriction needed to achieve a pressure of 100 mm Hg was 26 +/- 8%. The results indicated that constriction of the cauda equina to a size less than 75 mm2 probably will affect the normal function of the nerve roots of the cauda.

Degenerative spondylolisthesis. Pathophysiology and results of anterior interbody fusion

With special attention to the articular facets, an inspection of dry human spinal columns, microradiographic studies of cadaveric specimens, and animal experiments revealed that development of degenerative spondylolisthesis is attributable to rotational strain on the facetal joints at the level of involvement. Disc degeneration predisposes to intersegmental instability and rotational strain, which result in secondary osteoarthritic change of the articular processes and segmental canal stenosis. Thirty-six patients with degenerative spondylolisthesis were treated with anterior interbody fusion (AIF) for segmental canal stenosis at the authors' hospital during 1958-1985. The surgical results of these patients reveal that AIF corrects malalignment of the lumbar spine by complete discectomy, reduces the slip and restores the disc height, and resolves nerve compression, both from the front and from behind, by enlargement of the stenosing canal. In addition, AIF has consistent and satisfactory clinical results at long-term follow-up evaluation because it resolves intersegmental instability, an important problem of degenerative spondylolisthesis. AIF is a reasonable and reliable treatment for patients younger than 60 years of age with segmental stenosis.

Changes in sensorimotor functions after spinal lesions evaluated in terms of long-latency reflexes

Lesions of the central afferent and efferent pathways cause onset-delays of long-latency EMG responses from anterior tibial muscle after passive dorsiflection of the ankle joint in standing subjects. In 23 patients with spinal tumour or cervical stenosis and clinical signs of a medullary lesion, short-, medium- and long-latency EMG responses from distal leg muscles after ankle dorsiflection were recorded prior to and after surgical intervention. Fifteen of the patients were re-examined between 1 and 2 years after surgery. The results of the follow-up study support the hypothesis of a supraspinal pathway for long-latency EMG responses in distal leg muscles and show their significance as a quantitative measure of sensorimotor functions.

Neurophysiologic investigation of patients with spinal stenosis

To study the role of neurographic, electromyographic, and psychophysic examinations when diagnosing spinal stenosis, the authors studied 64 patients (mean age, 64 years) with myelographically verified spinal stenosis. Sixteen patients showed signs of total occlusion of the dural sack. Twenty-four patients with spinal claudication but with normal myelograms constituted a comparison group (mean age, 57 years). Normal reference values were obtained from 50 men aged 28-63 years. In spinal stenosis with total occlusion, bilateral neurogenic changes were registered in 87.5%, without total occlusion in 81%, and in spinal claudication with a myelogram of normal width in 29%. The corresponding frequencies of multisegmental EMG abnormalities were 94%, 75%, and 21%, respectively. Motor conduction velocity was normal in spinal stenosis except in cases with total occlusion. High thresholds were found to vibration and temperature changes in the legs, much like in patients with polyneuropathy. However, polyneuropathy was found in only a minority of the patients.

Intraoperative use of dermatomal somatosensory-evoked potentials in lumbar stenosis surgery

This report concerns the use of dermatomal somatosensory-evoked potentials (DSEPs) for intraoperative monitoring in the surgical management of a group of patients with lumbar spinal stenosis. Thirty patients with lumbar spinal stenosis underwent preoperative evaluation by DSEPs by use of electrical stimulation of the skin corresponding to the L4, L5, and S1 dermatomes. The specific dermatome to be monitored intraoperatively was selected by correlating those data with physical and radiographic findings and, in certain cases, the results of selective nerve root blocks. Intraoperative baseline (predecompression) DSEP values were obtained after positioning the patient on the operative frame. Monitoring was performed during surgery and post-decompression values were obtained after neural decompression. For six cases of unilateral nerve root decompression, an average 9-msec decrease in latency was noted on the operated side and a 3-msec decrease on the nonoperated side. For 24 cases of bilateral decompression, an average 8-9-msec decrease in latency was noted bilaterally. This method has been found helpful in assessing the adequacy of neural decompression intraoperatively.

Comparative study of clinical and surgical findings and cortical somatosensory evoked potentials in patients with lumbar spinal stenosis and disc protrusion

This paper is dealing with a comparative study of clinico-surgical findings and cortical somatosensory evoked potentials (CSEP's) recordings after stimulation of the right and left common peroneal nerve behind the fibula head, in twenty five patients suffering from lumbar spinal stenosis and disc prolapse. In all instances, the latencies of the first positive wave (the waveform also, when the latency was not discrete) were evaluated. The neurophysiological findings were verified by surgery. In combination with other roots, L3 root was affected in 1 patient, L4 in 6, L5 in 13 and S1 in 11. L5 was affected alone in 11 and L5 and S1 were impaired in combination in 11 patients. Seven patients presented sural atrophy. The results of the neurophysiological study are described below: There was delayed response on both sides in six patients, while in ten patients delayed response was found on one (affected) side, inconclusive responses in seven and in two normal. Myelography and CT Scan were performed pre-operatively to ascertain disc protrusion and establish stenosis criteria. The surgical findings were: clear disc protrusion in 4 patients, stenosis in one and combined lesions in 20 (including central disc protrusion in seven). Sixteen patients out of twenty-five had a follow up neurophysiological evaluation in addition to the clinical follow up examination. In thirteen of the above patients, (taken with the clinical progress) the re-examination gave improved neurophysiological data both as regards latency and P1 waveform. It was obvious that high value latencies were associated with long standing clinical symptoms while at the same time root compression involved more than one level. Regarding the neurophysiological data and the surgical findings, it was found that in the majority of the cases (92%) these two parameters matched together, so that in such cases a possible prediction of the operative outcome can be given.

Thoracic spinal canal stenosis

Hypertrophy of the posterior spinal elements leading to compromise of the spinal canal and its neural elements is a well-recognized pathological entity affecting the lumbar or cervical spine. Such stenosis of the thoracic spine in the absence of a generalized rheumatological, metabolic, or orthopedic disorder, or a history of trauma is generally considered to be rare. Over a 2-year period the authors have treated six cases of thoracic myelopathy associated with thoracic canal stenosis. In four patients the deficits developed gradually and painlessly. The three older patients had a clinical profile characterized by complaints of pseudoclaudication, spastic lower limbs, and evidence of posterior column dysfunction. Two patients were younger adults with low thoracic myelopathy associated with local back pain after minor trauma. Both patients also had congenital narrowing of the thoracic spinal canal. Oil and metrizamide contrast myelography in the prone position were of limited value in diagnosing this condition; in fact, myelography may be misleading and result in erroneous diagnosis of thoracic disc protrusion, when the principal problem is dorsal and lateral compression from hypertrophied facets. Magnetic resonance imaging and computerized tomography sector scanning were more useful in the diagnosis of this disorder than was myelography. Thoracic canal stenosis may be more common than is currently recognized and account for a portion of the failures in anterior and lateral decompression of thoracic disc herniations.

A technique to evaluate an internal spinal device by use of the Selspot system: an application to Luque closed loop

A technique to study the effects of spinal injury and stabilization in terms of load-deformation behavior is described. Fresh human cadaveric ligamentous spine segments (T12-sacrum) were potted and clinically relevant loads applied through the loading frame attached to the topmost vertebra of the specimen. The resulting three-dimensional motion responses of each vertebra for the normal specimen were recorded with the Selspot II System. The specimen was injured at the L4-5 motion segment to represent a typical surgical decompression used in treating patients with spinal stenosis and tested again. The decompressed (or injured) motion segment was stabilized with a Luque closed-loop (Luque rectangle) system before repeating the test protocol. The data of these tests indicate that the injury (surgical decompression) at the L4-5 motion segment leads to a significant increase in motion--in flexion, extension, and axial modes--indicating the possible necessity for stabilization of the injured segment. The closed-loop system reduces the motion at the injured level, with respect to normal specimen behavior, by 35%. Therefore, the system does not provide complete immobilization (100% reduction with respect to normal specimen behavior). The stabilizing effects of the closed loop in lateral bending are not significant and are marginal in axial motion. The motion across the L3-4 motion segment in flexion increases significantly after stabilization. The clinical implications and the need for further studies are also discussed.