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.     

Foraminal and extraforaminal lumbar disk herniations

Thirteen patients with foraminal or extraforaminal lumbar disk herniation were treated during a 32-month period. Myelography and magnetic resonance imaging proved to be ineffective in identifying the lesion in most patients. High-resolution computed tomography demonstrated the lesions in all patients, and the findings were subsequently confirmed at surgery. Surgical treatment consisting of disk fragment removal and nerve root decompression was effective in relieving radicular pain.     

Two-level spinal stenosis in minipigs. Hemodynamic effects of exercise

STUDY DESIGN: Twenty-two G?ttingen minipigs were trained to run on a treadmill. Two-level lumbar spinal stenosis was created in 12 pigs, 10 were unoperated control subjects. Blood flow of the spinal cord and nerve roots was determined with microspheres at rest, during exercise, and after exercise. OBJECTIVES: To study the effect of lumbar spinal stenosis and exercise on blood flow of spinal neural tissue. SUMMARY OF BACKGROUND DATA: Neurogenic claudication, the key symptom of lumbar spinal stenosis, may be caused by vascular impairment or mechanical distress of neural tissue during exercise. Experimental compression of the cauda equina causes reversible nerve root edema, stasis, blood flow decrease, and compromised neural function. The vascular pathophysiology of spinal stenosis during exercise has not been studied previously. METHODS: Pigs were trained daily for 3 months. Two-level 25% lumbar spinal stenosis was introduced by placement of stenosing bands around the dural sac. Neurologic function was monitored before surgery by evoked potentials and after surgery by the Tarlov score. Regional blood flow in lumbosacral neural tissue was measured 3 days after chronic catheterization using microspheres at rest, during exercise at 3 km/h for 15 minutes, and at rest 30 minutes after exercise. RESULTS: Blood flow of grey and white matter increased during exercise in both groups, with no differences between groups. slight hyperemia prevailed after exercise in white matter of the stenotic area but not in grey matter. Nerve root blood flow was largely unchanged in control subjects during exercise but was reduced in spinal stenosis at rest, further depressed during exercise, and normalized after exercise. Dural blood flow was elevated throughout. CONCLUSION: The study suggests that exercise-induced impairment of spinal nerve root blood flow plays a role in the pathophysiology of neurogenic claudication.     

Changes in symptom and thermography images after lumbar sympathetic ganglion block

In 35 lower limbs of 22 patients with peripheral circulation disturbance, we evaluated the effects of lumbar sympathetic ganglion block (LSGB) by skin temperature difference (delta T) between the two measured by thermography before and after LSGB. We divided the patients into two groups; ASO group (n = 15): patients with chronic arterial occulusive diseases, and nonASO group (n = 7): those with peripheral circulation disturbance partly due to decrease nervous function. After LSGB, we recognized a significant increase in delta T and remission of ischemic symptoms in all the patients of nonASO group and those in early stage of ASO group. This suggests that in ASO group LSGB should be applied as soon as possible to obtain good outcome, and thermography is useful to evaluate the effects of LSGB in patients with peripheral circulation disturbance of the lower limbs.     

Intradural lumbar disc herniations: report of three cases

Intradural lumbar disc herniation is a rare pathological entity. Three new cases among a series of 5000 lumbar spine operations are added to the about 60 previous case reports in the literature. None of our patients had undergone lumbar spine surgery before. In one patient the location of the free disc fragment was medial within the dural sac; in two patients the free disc fragment had penetrated the dural sac from the axilla of the nerve root. Pathogenesis is discussed (congenital adhesions of the dura mater to the posterior longitudinal ligament at the lower lumbar spine; weakness of the dura mater ventrally and at the axilla of the nerve root). By multiplanar MRI, the free disc hernia within the dural sac may be shown preoperatively.     

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).     

Electrophysiologic analysis of the lumbosacral radiculopathy using nerve root conduction velocity (NRCV) and cauda equina action potentials (CEAP)

Nerve root conduction velocity (NRCV) and cauda equina action potential (CEAP) have been measured to assess the severity of lumbosacral radiculopathy, the level-specific diagnosis of the symptomatic roots, and to predict the outcome. This study included 71 patients (40 males, 31 females, average age of 54 years at the time of surgery) who underwent decompressive surgery for lumbar radiculopathy. The NRCV and CEAP were directly measured during the operation. The NRCV decreased significantly with progression of radicular symptoms. The NRCV showed a marked reduction in the nerve roots of the patients with a two years or longer history of radicular symptoms; or those with compression of the nerve roots on the imaging examinations; or nerve roots that were considered to have been subjected to persistent compression over a prolonged period with severe inflammation and adhesions. Multivariative analyses suggested that the NRCV correlated closely to the postoperative neurologic recovery, and the outcome of the lumbosacral radiculopathy could be predicted to some extent by measurements of NRCV. The level-specific diagnosis of the radiculopathy could be determined when the CEAP showed a more than 30% left-right potentials difference.     

The vesico-ureteric junction in three cases of primary obstructive megaureter associated with ectopic ureteric insertion

OBJECTIVE: Diabetic foot problems due to angiopathy and neuropathy account for 50% of all nontraumatic amputations and constitute a significant economic burden to society. Low-intensity laser irradiation has been shown to induce wound healing in conditions of reduced microcirculation. We investigated the influence of low-intensity laser irradiation by means of infrared thermography on skin blood circulation in diabetic patients with diabetic microangiopathy. RESEARCH DESIGN AND METHODS: Thirty consecutive patients with diabetic ulcers or gangrenes and elevated levels of glycosylated hemoglobin were randomized by blocks of two to receive either a single low-intensity laser irradiation with an energy density of 30 J/cm2 or a sham irradiation over both forefoot regions in a double-blind placebo-controlled clinical study. Skin blood circulation as indicated by temperature recordings over the forefoot region was detected by infrared thermography. RESULTS: After a single transcutaneous low-intensity laser irradiation, a statistically significant rise in skin temperature was noted (P < 0.001 by ANOVA for repeated measurements), whereas in the sham-irradiated control group, a slight but significant drop in temperature (P < 0.001) was found. Subsequently performed contrasts for comparison of measurements before and after irradiation revealed significant temperature increases at 20 min of irradiation time (P < 0.001), at the end of the irradiation (P < 0.001), and 15 min after stopping the irradiation (P < 0.001). In the sham-irradiated feet, the drop in local skin temperature was not significant at 20 min (P = 0.1), but reached significance at the end of the sham-irradiation procedure (P < 0.001) and 15 min after the end of sham irradiation (P < 0.001). CONCLUSIONS: The data from this first randomized double-blind placebo-controlled clinical trial demonstrate an increase in skin microcirculation due to athermic laser irradiation in patients with diabetic microangiopathy.     

Lower urinary tract symptoms in lumbar root compression syndromes: a prospective survey

STUDY DESIGN: A prospective, observational survey. OBJECTIVES: To describe lower urinary tract symptoms in uncomplicated lumbar root compression syndromes with special reference to prevalence, nature, and severity, and to analyze whether the occurrence of lower urinary tract symptoms correlates with age, pain, analgesic intake, or the type and level of compression. SUMMARY OF BACKGROUND DATA: Lower urinary tract symptoms with lumbar root compression are well known in the classic but rather rare cauda equina syndrome. However, micturition difficulties seem to be far more frequent in lumbar root compression syndromes. METHODS: One hundred eight male patients admitted for surgery for lumbar disc herniation or spinal stenosis were investigated with an extensive questionnaire about their micturition. RESULTS: Fifty-five percent had significant lower urinary tract symptoms. Eighty percent of the patients with spinal stenosis had symptoms. Thirty-three patients had irritative symptoms, 36 had obstructive symptoms, and 23 had retention symptoms. Twenty-four had severe symptoms. Median compression resulted in more symptoms than paramedian compression. There was no correlation between age, level of compression, drug intake, or pain score and lower urinary tract symptoms. CONCLUSIONS: Lower urinary tract symptoms of mixed type occur with a high prevalence in male patients with lumbar root compression syndromes referred for neurosurgical evaluation and treatment.     

High- and low-bar squatting techniques during weight-training

STUDY DESIGN: Tissues in the area of herniated lumbar discs were examined for inflammatory cytokines to elucidate the causes of sciatic pain in lumbar disc herniation. OBJECTIVES: To determine the role of inflammatory cytokines in the stimulation of sciatic pain in lumbar disc herniation. SUMMARY OF BACKGROUND DATA: It is postulated that in addition to mechanical compression of lumbar nerve roots and sensory root ganglia by herniated discs, there is a chemical stimulus to the production of sciatic leg pain. The exact mechanisms of chemical stimulation are not clearly defined. METHODS: During surgery, cases of lumbar disc herniation in 77 patients were classified macroscopically into protrusion, extrusion, and sequestration types. Tissues adjacent to nerve roots at the herniation were excised and analyzed biochemically and immunohistochemically for the presence of inflammatory cytokines and for the production of these cytokines and prostaglandin E2 in vitro. RESULTS: The homogenates of samples were analyzed for interleukin-1 alpha, interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and granulocyte-macrophage colony stimulating factor, which were detectable. Most of the cytokine-producing cells were histiocytes, fibroblasts, or endothelial cells in extrusion and sequestration types, and chondrocytes in protrusion type. The secretion of these cytokines and prostaglandin E2 was decreased by the addition of betamethasone. The prostaglandin E2 production was dramatically enhanced by additional interleukin-1 alpha, but decreased by the addition of tumor necrosis factor-alpha. CONCLUSION: The results demonstrate that at the site of lumbar disc herniation, inflammatory cytokines such as interleukin-1 alpha are produced, which increases prostaglandin E2 production. Further studies are required to elucidate the role of inflammatory cytokines in causing sciatic pain.     

Spontaneous epidural hematoma as a cause of sciatic pain in a schoolboy

A previously healthy 13-year-old boy began to manifest radiating pain in his left leg after heavy physical exertion during judo training. He also had a sensation of numbness in his left buttock and leg. Initially, the patient was treated conservatively with a clinical diagnosis of disc herniation. However, following 3 months of conservative treatment, there was no relief of pain. Magnetic resonance imaging of the lumbar spine demonstrated an epidural mass causing compression of the dural sac at the L4-L5 disc level. During surgery, the L5 nerve root was found to be severely compressed in the spinal canal because of a chronic epidural hematoma. Following microsurgical removal of this hematoid mass, the patient had a good recovery. Spontaneous epidural hematomas in the lumbar region are rare, and only a few cases presenting with features simulating those caused by a disc herniation have been reported. Our patient represents the first such case described in a child.     

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.     

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.     

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.     

Assessment of flail mitral leaflets by dynamic three-dimensional echocardiographic imaging

Patients with diabetic amyotrophy may have an inflammatory vasculopathy and may obtain reversal of neurological deficits with immunosuppression. We present a patient with NIDDM, subacute onset of painful asymmetric polyradiculopathy, and unilateral enhancement of lumbar nerve roots on MRI. Clinical improvement and resolution of nerve root enhancement occurred with immunosuppression. We suggest, therefore, that nerve biopsy and gadolinum-enhanced lumbosacral MRI be performed in all patients presenting with diabetic amyotrophy. If nerve root enhancement is present or if nerve biopsy shows perivascular infiltrates, we recommend a trial of immunosuppression.     

Occult lumbar lateral spinal stenosis in neural foramina subjected to physiologic loading

PURPOSE: To measure the effect of extension, flexion, lateral bending, and axial rotation loads applied to the spine on the anatomic relationship of the spinal nerves in the neural foramen to the ligamentum flavum and the intervertebral disk, anc to determine the effect of disk degeneration on the response to loading. METHODS: Cadaveric lumbar motion segments were examined with CT and MR imaging, loaded with pure moment forces, frozen in situ, reexamined with CT, and sectioned with a cryomicrotome. The morphology of the intervertebral disks was classified on the basis of the appearance of the cryomicrotome sections. The neural foramina were classified as having no evident stenosis, as being stenotic, as having occult stenosis, or as showing resolved stenosis on the basis of the images and sections before and after loading. The stenotic and nonstenotic foramina were stratified by disk level, intervertebral disk classification, and type of loading applied. The effect of spinal level, disk type, and load type on the prevalence of stenosis was studied. RESULTS: On average, extension, flexion, lateral bending, and axial rotation resulted in the ligamentum flavum or intervertebral disk contacting or compressing the spinal nerve in 18% of the neural foramina. Extension loading produced the most cases of nerve root contact, and lateral bending produced the fewest cases. Each of the loading types resulted also in diminished contact between the spinal nerve and the intervertebral disk or ligamentum flavum in some cases. Disk degeneration significantly increased the prevalence of spinal stenosis. All foramina associated with advanced disk degeneration and half of the foramina associated with disks having radial tears of the annulus fibrosus either developed occult stenosis or were stenotic before loading. CONCLUSIONS: The study supports the concept of dynamic spinal stenosis; that is, intermittent stenosis of the neural foramina. Flexion, extension, lateral bending, and axial rotation significantly changed the anatomic relationships of the ligamentum flavum and intervertebral disk to the spinal nerve roots.     

Pain drawing in the evaluation of low back pain

Pain drawings were obtained from three groups of patients: 51 with lumbar disc herniation; 55 with lumbar stenosis, and 42 with benign low back pain. On grid assessment, patients with disc herniation and stenosis who complained of radiating pain or intermittent claudication had a significantly larger number of grids for the extremities than those with benign low back pain. In studies of the relation between the characteristics of the pain drawing and the outcome of treatment, most patients with 19 grids or less, or a score of 3 points or less, had a satisfactory outcome. Those with more grids or a higher score tended to be unsatisfactory. Pain drawing permits differentiation of the three patterns of pain and is useful for predicting the outcome of treatment.     

Intraradicular and intradural lumbar disc herniation: experiences with nine cases

BACKGROUND: Intraradicular or intradural disc herniation is a very rare complication of spinal degenerative processes. The aim of our study is to analyze the clinical spectrum, the mechanism, and the treatment of this acute spinal pathology. METHODS: Retrospective clinical examination was performed in nine personal cases of intradural disc herniation: among these, six were associated with lateral perforation, the remaining three with intradural herniation and ventral perforation. A review of the literature concerning mainly the frequency pathogenesis and diagnosis of intradural disc herniation has also been done. RESULTS: Nine cases of intradural herniations comprise 1.51% of the 593 cases of ruptured lumbar disc that underwent surgery from 1980 to 1992. The site most frequently involved is at level L4-L5, and 30% of patients have previously undergone surgery for lumbar disc herniation. Most patients reported in literature and in our present series have been complaining of a chronic history of sciatica, complicated later by bilateral neurologic signs. In the present series, diagnosis was obtained by means of myelography and computerized tomography; magnetic resonance imaging was performed in one case. All patients underwent surgery, reporting excellent results in five cases and good results in the other four. Surgery was performed either with an interlaminar approach or with a bilateral laminectomy in cases of ventral perforation. CONCLUSIONS: There is no typical neuroradiologic picture of intraradicular herniation, while a total or subtotal block is frequently observed in intradural ventral perforations. Dural perforation is often an unexpected intraoperative finding. Surgical treatment is always necessary. Favorable results are obtained if surgical treatment is carried out before the neurologic deficit becomes too pronounced.     

Groin pain associated with lower lumbar disc herniation

STUDY DESIGN: Retrospective clinical and magnetic resonance imaging study of patients with groin pain associated with lower lumbar disc herniation. OBJECTIVES: To demonstrate the clinical features and magnetic resonance imaging findings of these patients. SUMMARY OF BACKGROUND DATA: Patients with lumbar disc herniation sometimes report groin pain. Little mention has been made, however, regarding the clinical features of groin pain stemmed from lower lumbar disc herniation until now, with only Murphey referring to groin pain in disc disease. METHODS: A total of 512 patients were diagnosed with singular lower lumbar disc herniation (L4-L5 and L5-S1) at Kakegawa City General Hospital between July 1990 and December 1993. Of these patients, 21 (4.1%) reported groin pain. The characteristic clinical features and magnetic resonance imaging findings of the 21 patients were investigated and compared with the features and findings of patients with no groin pain. RESULTS: Patients with groin pain had a higher mean age and lower rate of low back pain, and L4-L5 discs were more likely to be involved than L5-S1 discs. In their magnetic resonance images, herniation tended to be more central than in patients with no groin pain. CONCLUSIONS: Elderly patients with L4-L5 protruding herniation of the anulus fibrosus were most likely to experience groin pain. The sinuvertebral nerve that innervates the posterior anulus fibrosus, the posterior longitudinal ligament, and the dura was indicated as the afferent nerve of groin pain.