Acquired dural arteriovenous malformations of the lumbar spine: case report

OBJECTIVE AND IMPORTANCE: Although dural arteriovenous malformations (AVMs) are considered to be acquired, no conclusive evidence has been obtained. The first case of dural AVMs of the lumbar spine that showed evidence supporting their being acquired lesions is described. CLINICAL PRESENTATION: A 27-year-old man was admitted to our hospital in November 1994, presenting with increasing pain and numbness in the left buttock to the left lower limb. Myelography and arteriography showed dural AVMs of the lumbar spine. However, the myelogram obtained before surgery for lumbar disc herniation in 1987 provided no findings suggestive of intradural vascular anomalies. INTERVENTION: Embolization procedures via the left iliolumbar arteries were performed. However, there was no improvement of the symptoms, and the patient underwent surgical treatment. CONCLUSION: The present report documents a case of dural AVMs of the lumbar spine that showed evidence supporting their being acquired lesions.     

Indication and clinical results of laminoplasty for cervical myelopathy caused by disc herniation with developmental canal stenosis

STUDY DESIGN: The outcome of a herniated disc in patients with cervical myelopathy treated by laminoplasty without discectomy and in those treated conservatively was studied by magnetic resonance imaging. OBJECTIVES: To compare the surgical results of laminoplasty with those of anterior spinal fusion in patients with myelopathy caused by to cervical disc herniation and to make a treatment strategy for cervical disc herniation depending on these results. SUMMARY OF BACKGROUND DATA: Anterior discectomy and spinal fusion have had acceptable surgical results, but many complications have been reported, especially adjacent segment degeneration and bone graft complications. METHODS: Forty-seven patients with cervical disc herniation were examined in this study. Of them, 32 patients (mean age, 56 years) underwent laminoplasty without resection of the herniated disc. Seven patients with mild cervical myelopathy and 8 patients with radiculopathy (mean age, 53 years) were treated conservatively. As a control group, 44 patients (mean age, 50.3 years) who underwent anterior spinal fusion were examined. All patients in the laminoplasty group also had congenital spinal canal stenosis in which the ventrodorsal canal diameter was less than 13 mm. The association between the outcome of a herniated disc and clinical features was investigated. The severity of myelopathy was evaluated according to the Japanese Orthopaedic Association's scoring system. Surgical outcomes were evaluated by the system of Hirabayashi for determining recovery rate. RESULTS: The recovery rate averaged 67.9% in laminoplasty and 68.8% in anterior spinal fusion. There were no significant differences between the groups. No patients underwent anterior spinal fusion after laminoplasty. Follow-up magnetic resonance imaging showed regression of the size of the herniated disc in 15 of the 20 patients in the laminoplasty group and in 12 of 15 patients treated conservatively. In the MRI studies of the natural course of disc herniation, the size of the herniated disc decreased to almost half in 1 to 2 months and almost disappeared within 3 months after surgery. CONCLUSIONS: The size of the herniated disc in cervical lesions regressed as it does in the lumbar lesions. Laminoplasty for patients with narrowed spinal canals showed favorable surgical results. Therefore, the therapeutic method for cervical disc herniation should be chosen after taking the natural history of the disc herniation into consideration.     

Neurologic signs in lumbar disc herniation. Preoperative affliction and postoperative recovery in 150 cases

We studied prospectively 165 consecutive patients operated on for lumbar disc herniations. Neurologic examination was performed preoperatively and at 4, 12, and 24 months postoperatively according to a protocol. Preoperatively 69% of the patients showed a neurological disturbance corresponding to the level of disc herniation and 62% a corresponding sensory deficit. Recovery of the neurological deficit was seen in half of the cases at 2 years postoperatively, the main part of this improvement occurred within 4 months after the operation. Neurologic recovery correlated to a good surgical outcome, and a short history of disc herniation prior to the operation correlated to postoperative neurologic improvement. The straight leg raising test correlated to preoperative neurologic deficit, but not to postoperative recovery. Motor power disturbance of the extensor hallucis longus muscle recovered in more patients than reflex disturbances. Sensory disturbances had the lowest recovery rate. Our study demonstrates a correlation between routine postoperative neurologic findings and the patient's self-assessed outcome of surgery.     

Vascular and visceral injuries associated with lumbar disc surgery: medicolegal implications

Symptomatic perforation of the anterior annulus fibrosus/anterior longitudinal ligament during surgery for herniated lumbar disc disease is one of the more solemn and sobering complications experienced by neurosurgeons or orthopedic surgeons. This complication frequently results in the death of the patient. Its occurrence is probably more common than the medical community would expect. The authors report 21 cases since 1985 in which an injury to an intra-abdominal vessel or viscera occurred. In all cases litigation resulted and a settlement or verdict was rendered. A review of the literature is presented and the medicolegal implications of symptomatic ventral perforations of the annulus fibrosus/anterior longitudinal ligament are discussed.     

Lumbar intervertebral disc herniation in children less than 16 years of age. Long-term follow-up study of surgically managed cases

STUDY DESIGN: In this retrospective study, the long-term clinical results of lumbar intervertebral disc herniation in children less than 16 years of age were reviewed. OBJECTIVES: To evaluate the effectiveness of surgical treatment including posterior discectomy, extraperitoneal anterolateral discectomy, and anterior interbody fusion for lumbar intervertebral disc herniation in children less than 16 years of age. SUMMARY OF BACKGROUND DATA: Although previous follow-up studies on surgically managed lumbar intervertebral disc herniation in children and adolescents generally reveal good outcomes, few reports have focused on the time course of clinical findings and the long-term results. METHODS: The outcome of subjective symptoms, clinical signs, and time-related change of the intervertebral disc space in 11 patients were evaluated with an average follow-up period of 9 years (range, 5-12 years). RESULTS: The posterior discectomy procedure relieved clinical symptoms quickly. In the case of central herniation with or without intervertebral instability, extraperitoneal anterolateral discectomy or anterior interbody fusion led to favorable long-term results. Clinical symptoms (lower back pain, leg pain) and neurologic disturbance disappeared within 3 months after surgery. Recovery of normal straight leg raising test results (tight hamstrings), however, required much more time than recovery of other symptoms. Narrowing of the intervertebral disc space progressed up to 3-6 months after discectomy, but then disc space widening occurred. CONCLUSIONS: Satisfactory long-term clinical results and early return to school life were obtained with each surgical procedure. It is important to aim toward an early return to school via surgical treatment.     

Regression of cervical disc herniation observed on magnetic resonance images

STUDY DESIGN: A retrospective study of cervical disc herniation using results of repeated magnetic resonance imaging examinations. OBJECTIVES: To clarify the cervical disc herniation morphological changes over time in order to establish a strategy for treatment. SUMMARY OF BACKGROUND DATA: In the authors' previous magnetic resonance imaging follow-up study of patients with lumbar disc herniation, spontaneous regression was observed in the sequestration-type lesions, and it was found that the tendency toward regression differed based on the anatomic position of extruded disc material. METHODS: Thirty-eight patients with cervical disc herniation who underwent repeated magnetic resonance imaging examinations were studied. The changes over time in herniated disc size were evaluated using this imaging technique. Evaluation showed the characteristics of those in whom spontaneous regression was found, such as extrusion pattern, and the clinical outcome was evaluated by symptoms. RESULTS: In 15 patients (40%), the volume of herniated material was decreased. The interval from onset of symptoms to the initial examination was significantly shorter in the regression group than in the group that showed no change in disc herniation. By extrusion pattern, cervical disc herniation, which was divided into migration type on sagittal view and lateral type on axial view, most frequently exhibited spontaneous regression. All of the patients with radicular pain and upper limb amyotrophy were treated successfully with conservative therapy. CONCLUSION: Although the possibility of the combination of hemorrhage and disc material could not be denied, active resorption of herniated material probably occurred during the acute phase. Extruded material exposed to the epidural space may be resorbed more quickly than that beneath the ligament. Vascular supply probably plays a role in the mechanism of resorption. The phase and position of extrusion were the significant factors affecting cervical disc herniation resorption. It was demonstrated that examination performed during the acute phase using magnetic resonance imaging is necessary for elucidation of the pathogenesis of cervical disc herniation, and that migrating, lateral-type herniations regress so frequently that conservative treatment should be chosen not only for patients with radicular pain, but also for those with upper limb amyotrophy.     

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.     

Epidural spinal infection. Variability of clinical and magnetic resonance imaging findings

STUDY DESIGN: This study evaluates the magnetic resonance characteristics of spinal epidural abscesses and their associated disc space infections. OBJECTIVES: The results were correlated with history, clinical, and laboratory findings to provide guidelines for early and appropriate diagnosis of epidural spinal infections. SUMMARY OF BACKGROUND DATA: Imaging signs of spinal infections have been reported before, but not with special attention to early clinical and imaging findings. METHODS: Thirteen patients (10 men, 3 women; age range, 32-64 years) with progressive sensorimotor deficit were studied. All patients had a neurologic examination after admission and a magnetic resonance imaging scan done within the first 48 hours. In all cases, T1-weighted images before and after administration of gadolinium were obtained. T2-weighted images were acquired in eight cases as well. Ten patients subsequently underwent open surgery; in three cases, a percutaneous biopsy and drainage was performed. RESULTS: Cervical discitis was found in five patients, and thoracic discitis was seen in another five cases. Three patients had an epidural infection without a concomitant discitis. Neurologic and clinical findings varied considerably. Despite clinical signs of spinal cord involvement, a spinal cord lesion was demonstrated only once. Signal change in T2-weighted images may be the first sign of disc space infection. Because a neurologic deficit may occur before any change is visible, follow-up examinations may be required if epidural infection is suspected on clinical grounds. CONCLUSIONS: Magnetic resonance imaging is the appropriate method for diagnostic work-up of progressive neurologic deficit resulting from epidural infection.     

Severe prolonged hypocalcaemia following pamidronate for malignant hypercalcaemia

A review of 105 consecutive cases of chymopapain chemonucleolysis for single level lumbar disc herniation was undertaken. Mean follow-up was 12.2 years (range 10-15.3). Patients were assessed using the Oswestry Disability Questionnaire. Eighty-seven patients were available for follow-up. An excellent or good response occurred in 58 patients (67%); four patients (4.5%) had a moderate response but were only minimally disabled. The treatment failed in 25 patients (28.5%) and 21 of these went on to surgery within a mean of 5.2 months (range 3 weeks-12 months). In 15 patients (71%) disc sequestration or lateral recess stenosis was found. Five of the remaining six cases had a large disc herniation at surgery. Surgery resulted in a significant improvement in nine cases. Discitis following chemonucleolysis occurred in six patients (5.7%). Chymopapain chemonucleolysis has a useful role in the management of lumbar intervertebral disc prolapse. However, its efficacy is dependent on careful clinical and radiological patient selection.     

Spontaneous thoracic spinal cord herniation. A case report

STUDY DESIGN: This is a case report. OBJECTIVE: To focus attention on spontaneous spinal cord herniation as a rare cause of myelopathy that can be diagnosed preoperatively and can be corrected surgically. SUMMARY OF BACKGROUND DATA: A 34-year-old woman presented with spastic paraparesis. Magnetic resonance imaging scan of the thoracic spine revealed anterior displacement and tethering of the cord at T6-T7 and a dorsal intradural arachnoid cyst. Excision of the cyst was performed without improvement in symptomatology. During reoperation the thoracic spinal cord hernia was discovered and was reduced intradurally. METHODS: The authors describe the clinical, radiographic, and surgical findings of this patient and review the findings from other reported cases. They discuss the proposed theories for the pathophysiology of the cord herniation and the surgical management. RESULTS: The patient had idiopathic thoracic spinal cord herniation as there was no history of previous spine surgery or injury. The authors believe that the cord herniated through a congenital dural defect, which resulted in the development of a pseudoarachnoid cyst dorsally to the hernia. The patient improved after intradural reduction of the hernia and closure of the dural defect. CONCLUSION: Idiopathic spinal cord herniation should be recognized as a cause of progressive myelopathy that can be managed successfully with microsurgical techniques.     

Folliculotropic mycosis fungoides with large-cell transformation presenting as dissecting cellulitis of the scalp

MRI is routinely used in the evaluation and management of patients with failed back surgery syndrome (FBSS). However, its value is unclear in the early detection of signs that can negatively affect that later course of surgical cases. The purpose of the present study is to describe the MR images of early postoperative MRI at 3 days in 30 unselected patients who underwent lumbar microdiscectomy, and to correlate the findings with follow up MRI at 8 weeks and with final outcome. The findings are correlated with literature data. Early postoperative MRI findings were consisting of pseudohernia in 24 patients (80%), annular rent in 23 patients (80%), and other non-specific postoperative findings. On the late MRI the pseudohernia persisted in 12 patients (50%), the annular rent in 4 patients (15%) and asymptomatic pseudo-spondylodiscitis was apparent in 3 patients (10%) as was a case of true spondylodiscitis. Therefore, early postoperative findings have limited value in the management of patients after surgery for lumbar disc herniation, since the images were not correlated with the immediate clinical course after surgery nor with the late radiological and clinical outcome. The evident imaging changes in the early postoperative period after lumbar disc surgery limit the accuracy of the interpretation of MRI examinations.     

Body mass index and height in patients requiring surgery for lumbar intervertebral disc herniation

The immediate preoperative body mass index and standing body height of 1128 patients who underwent surgery for lumbar intervertebral disc herniation were compared in a cross-sectional study with the corresponding values obtained from a general population sample. The material was divided into sex- and age-specific subgroups. To delineate possible differences, the 99% confidence intervals for the anthropometric mean values were constructed instead of hypothesis testing. With the exception of the oldest age group, from 50 to 59 years, the patients who underwent surgery for a disc herniation were more obese and taller than the population on average in all other sex- and age-specific subgroups. The major contrast emerged in women aged 20-29 years, in whom the 99% confidence interval for the mean body mass index of the patients undergoing surgery on was 25.1-27.3 kg/m2 versus 22.3-23.1 kg/m2 in the general population. In patients aged 20-39 years the mean body mass index was increased also when the body height of the patients was less than the mean value of the general population samples. Both an increased body mass index and a tall stature seem to have a clear association with those severe lumbar intervertebral disc herniations that require operative 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.     

Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: implications for regional anesthesia. Mayo Perioperative Outcomes Group

Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. Implications: The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.     

The surgical treatment of low back pain

If nonoperative management fails to relieve a clearly identifiable and surgically treatable cause of lumbar pain, then surgery may be beneficial. Certain "red flags" indicate the need for urgent or emergent surgical intervention. Low back pain is associated with several degenerative conditions in the lumbar spine, including degenerative disc disease, spinal stenosis, spondylolisthesis, degenerative scoliosis, facet joint syndrome, and disc herniation.     

Gouty arthropathy of the lumbar spine: a case report and review of the literature

STUDY DESIGN: A patient with hyperuricemia developed symptoms from lateral recess stenosis attributed to gouty arthropathy of a lumbar facet joint. OBJECTIVE: To present the diagnosis and management of gouty arthropathy of the lumbar spine in one individual. SUMMARY OF BACKGROUND DATA: The symptoms and treatment of a patient with intra-articular gout of a lumbar facet are presented and contrasted with other cases of spinal extra-articular gout found in the literature. METHODS: A patient with hyperuricemia reported back pain and symptoms consistent with lateral recess stenosis. Conservative treatment failed, and, after further evaluation, a successful decompressive laminectomy was performed. Pathology revealed intra-articular urate crystal deposition. RESULTS: This patient's unilateral S1 radiculopathy corresponded with magnetic resonance and computed tomography studies documenting unilateral lateral L5-S1 lateral recess stenosis secondary to intra-articular gouty arthropathy. As anticipated, the serum uric acid also was elevated. Since surgical decompression with unilateral laminotomy was performed, the patient has been symptom-free for 2 years. CONCLUSION: Although rare, gouty arthropathy of the lumbar facet joint should be considered in all patients with neurologic symptoms and known or suspected gout. Optimization of pharmacologic treatment is indicated for patients suspected of having gouty neuropathy. Surgical decompression is indicated if conservative management with Indocin, nonsteroidal anti-inflammatory agents, and allopurinol fails to reverse neurologic dysfunction.     

Adding posterior lumbar interbody fusion to pedicle screw fixation and posterolateral fusion after decompression in spondylolytic spondylolisthesis

STUDY DESIGN: This is a retrospective study analyzing 76 patients treated by decompression, pedicle screw instrumentation, and fusion for spondylolytic spondyiolisthesis with symptomatic spinal stenosis. OBJECTIVES: To verify the advantages of adding posterior lumbar interbody fusion to the usual posterolateral fusion with pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA: Stabilization after decompression of spondylolytic spondylolisthesis is difficult because of a lack of fusional bone bases, gap between the transverse process bases, and incompetent anterior disc support. Posterior lumbar interbody fusion offers anterior support, reduction, and a broad fusion base. METHODS: Forty patients were treated with posterolateral fusion, and 36 were treated with additional posterior lumbar interbody fusion. They were compared for union, reduction of the deformity, and clinical results. RESULTS: The patients were followed up for more than 2 years. Nonunion was observed in three patients who underwent posterolateral fusion (7.5%), and no cases of nonunion was found in patients who underwent posterior lumbar interbody fusion. Reduction of slippage was 28.3% in those who underwent posterolateral fusion and 41.6% in those who had posterior lumbar interbody fusion (P = 0.05). In the posterolateral fusion group, eight patients (20%) had recurrence of deformity, with loss of reduction more than 50%. Hardware failures occurred in two patients who had posterolateral fusion. There was no major neurologic complications in both groups. Both groups had satisfactory results in more than 90% of patients, with marked improvement of claudication. However, subjective improvement of back pain by Kirkaldy-Willis criteria revealed differences in the excellent results. An excellent result was reported by 45% in the posterolateral fusion group and by 75% in posterior lumbar interbody fusion group. CONCLUSIONS: The addition of posterior lumbar interbody fusion to posterolateral fusion after a complete decompression and pedicle screw fixation is a recommended procedure for the treatment of spondylolytic spondylolishesis with spinal stenosis.     

Magnetic resonance imaging and clinical follow-up: study of 27 patients receiving chiropractic care for cervical and lumbar disc herniations

OBJECTIVE: To prospectively investigate the effect of chiropractic management on clinical and anatomical outcome of disc pathomorphology in previously magnetic resonance imaging (MRI)-documented disc herniation of the cervical and lumbar spine. SETTING: Private practice. SUBJECTS: Twenty-seven patients with MRI-documented and symptomatic disc herniations of the cervical or lumbar spine. A prospective clinical case series. DESIGN: All patients were evaluated before commencement of chiropractic care by MRI scans for presence of disc herniations. Precare evaluations also included clinical examination and visual analog scores. Patients were then treated with a course of care that included traction, flexion distraction, spinal manipulative therapy, physiotherapy and rehabilitative exercises. All patients were re-evaluated by postcare follow-up MRI scans, clinical examination and visual analog scores. Percentage of disc shrinkage on repeat MRI, resolution of clinical examination findings, reduced visual analog pain scores and whether the patient returned to work were all recorded. RESULTS: Clinically, 80% of the patients studied had a good clinical outcome with postcare visual analog scores under 2 and resolution of abnormal clinical examination findings. Anatomically, after repeat MRI scans, 63% of the patients studied revealed a reduced size or completely resorbed disc herniation. There was a statistically significant association (p < .005) between the clinical and MRI follow-up results. Seventy-eight percent of the patients were able to return to work in their predisability occupations. CONCLUSION: This prospective case series suggests that chiropractic care may be a safe and helpful modality for the treatment of cervical and lumbar disc herniations. A random, controlled, clinical trial is called for to further substantiate the role of chiropractic care for the nonoperative clinical management of intervertebral disc herniation.     

Spinal anesthesia for lumbar disc surgery: review of 576 operations

Neurologic complications accompanying spinal anesthesia were examined in 576 lumbar disc operations on 507 patients. The single serious complication did not seem attributable to the choice of anesthetic method. Minor neurologic complications, with the exception of spinal headache, could be explained by surgical manipulation. The authors conclude that spinal anesthesia is safe for surgical operations on the laterally herniated lumbar disc.