Predictive signs of discogenic lumbar pain on magnetic resonance imaging with discography correlation

STUDY DESIGN: The correlation between discogenic lumbar pain and disc morphology was investigated by using magnetic resonance imaging and discography. OBJECTIVES: To assess the various pathologic parameters seen on magnetic resonance imaging in patients with discogenic lumbar pain and to correlate them with observations on discography. SUMMARY OF BACKGROUND DATA: Although numerous previous studies on the subject have been performed, the correlations between various pathologic findings on magnetic resonance imaging and pain reproduction by provoked discography have not been explained fully. METHODS: One hundred and one lumbar discs in 39 patients were studied with magnetic resonance imaging and pain provocation discography. When pain reproduction under discography was concordant, various pathologic parameters on magnetic resonance imaging were analyzed by three statistical parameters to determine the associated magnetic resonance imaging findings. RESULTS: Radial tears commonly are demonstrated on magnetic resonance imaging in discs with concordant pain on discography. The presence of these tears is not a reliable predictor of a painful disc on discography. Although a high-intensity zone on T2-weighted images is a relatively reliable predictor of pain, the statistical values were lower than those in previous studies. Massive degeneration and severe disc height loss were rare in this population. These findings were good predictors of pain on disc injection. CONCLUSIONS: Although the lumbar intervertebral discs with posterior combined anular tears are likely to produce pain, the validity of these signs for predicting discogenic lumbar pain is limited.     

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 stiffness of lumbar spinal motion segments with a high-intensity zone in the anulus fibrosus

STUDY DESIGN: Biomechanical and anatomic study of human cadaveric spinal motion segments. OBJECTIVES: To measure the stiffness of spinal motion segments by disc type and by load type (flexion, extension, axial rotation, or lateral bending). To compare stiffness in motion segments with and without a high-intensity zone or radial tear in the anulus fibrosus. SUMMARY OF BACKGROUND DATA: The high-intensity zone, that is a linear zone of high-intensity on T2-weighted magnetic resonance images corresponding to a radial tear in the anulus fibrosus, is a marker for a painful disc at discography. The high-intensity zone is hypothetically associated with diminished stiffness of the motion segment. METHODS: Human cadaveric lumbar spinal motion segments with normal disc morphology or a high-intensity zone of the anulus fibrosus were selected on the basis of magnetic resonance imaging. The motion segments were subjected to incremental flexion, extension, rotation, and lateral bending torques. Rotation was measured with a kinematic system. Torque-rotation curves and stiffness were calculated for each motion segment and for each torque. The motion segments were sectioned on a cryomicrotome to verify the disc morphology as normal or as that of a radial tear. RESULTS: In four motion segments with normal discs, stiffness was greater in axial rotation (8.4 Nm/degree) than in lateral bending (2.3 Nm/degree), flexion (1.8 Nm/degree), or extension (2.6 Nm/degree). In 16 motion segments with a high-intensity zone, stiffness was 2.4 Nm/degree in axial rotation, and less severely reduced in lateral bending, flexion, and extension. Stiffness in motion segments with a high-intensity zone was significantly less with smaller than with larger axial rotation loads. CONCLUSIONS: The presence of a high-intensity zone in the intervertebral disc is associated with reduced stiffness of motion segments. The reduction is greater in axial rotation than in other torques. The reduction is more in smaller than in larger axial torques.     

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.     

L5 root compression caused by degenerative spinal stenosis of the L1-L2 and L2-L3 spaces

STUDY DESIGN: A severe bilateral L5 root lesion associated with spinal stenosis at L1-L2 and L2-L3 is described. OBJECTIVE: To describe clinical findings and the difficulty in obtaining a correct diagnosis of L5 Root Compression. SUMMARY OF BACKGROUND DATA: The disorder reported in this study has not been reported previously. Only one similar case has been described in the literature: an L5 root compression at L1-L2 caused by disc herniation. METHODS: Diagnosis was obtained by using computed tomography scanning, magnetic resonance imaging, and computed tomography myelography. The findings at L5-S1 were minimal to justify the patient's clinical symptoms, but a detailed study of the upper levels revealed spinal stenosis at L1-L2 and L2-L3, which could have been causing L5 and S1 root compression. A decompressive laminectomy and partial facetectomy in both levels were performed. RESULTS: The patient's pain and claudication disappeared, and clinical symptoms associated with the right L5 root improved. The left L5 root deficit remained stable. CONCLUSION: An unusual case of L5 root compression caused by degenerative stenosis of L1-L2 and L2-L3 is described.     

Injuries in the adolescent porcine spine exposed to mechanical compression

STUDY DESIGN: An experimental porcine study in which functional lumbar spinal units were tested in compression to failure. Biomechanical, radiographic, magnetic resonance imaging, and histological characteristics are described. OBJECTIVES: To explain the different patterns of injury seen in adults and adolescents resulting from traumatic injury to the vertebrae and to explain the mechanism behind traumatic displacement of the ring apophysis seen in athletes. SUMMARY OF BACKGROUND DATA: Recent investigations of the spine in adolescent who have sustained trauma have shown injuries to the growth zone, whereas studies of adults have shown injuries to the vertebral body. A higher frequency of abnormalities in the discs, the vertebral bodies, the endplates, and the ring apophyses has been demonstrated in athletes with high loads on the spine. There is controversy over the etiology of these changes. METHODS: Twelve functional lumbar spinal units (vertebra-disc-vertebra) obtained from six young male pigs were tested in compression to failure. All units were examined with plain radiography and magnetic resonance imaging before and after compression. After the compression, histologic samples were taken from the injury site. RESULTS: Identical traumatic changes were seen in all functional lumbar spinal units, i.e., fracture in the endplate through the growth zone posteriorly and displacement of the anulus fibrosus with a bony fragment at the point of insertion of the vertebra. The nucleus pulposus was ruptured and displaced through the fracture line in all cases. The injuries were not seen on radiographs but were detected on magnetic resonance images, as confirmed on microscopic and histologic examination. CONCLUSION: This study shows that the weakest part of the lumbar spine of the juvenile pig, when compressed, is the growth zone and the junction between the point of insertion of the anulus fibrosus and the vertebra. This location of weakness may explain the high frequency of disc degeneration and "persisting apophysis" seen in the spine of athletes.     

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.     

Changes in cross-sectional area of psoas major muscle in unilateral sciatica caused by disc herniation

STUDY DESIGN: A clinical prospective cohort study of 15 healthy volunteers and 25 patients with unilateral sciatica from single-level disc herniation. OBJECTIVES: To detect any changes in the cross-sectional area of the psoas major muscle in patients with single-level (lateral to mediolateral) disc herniation causing unilateral sciatica. SUMMARY OF BACKGROUND DATA: The exact role of the psoas major muscle in the origin of low back pain and sciatica has not been clarified. METHODS: Fifteen healthy volunteers and 25 patients with unilateral sciatica from single-level disc herniation were subjected to magnetic resonance imaging of the lumbar spine. The cross-section area of the psoas major muscle on either side was recorded, and differences were noted. In patients, the cross-section area of either side was compared with and duration of sciatica was related to changes in the cross-section area. RESULTS: Insignificant variation in the cross-section area of the psoas major was observed in volunteers. In the patient group, significant reduction in the cross-section area of the psoas major was observed at the level and the site of the disc herniation. A significant correlation between cross-section area of the psoas major and ipsilateral continuous sciatica was found. There was no relation between the reduction of the cross-section area and the amount of disc herniation. CONCLUSION: The cross-section area of the psoas major is ipsilaterally decreased in unilateral lumbar disc herniation. The reduction in cross-section area is positively correlated with the duration of continuous sciatica.     

Monocyte chemoattractant protein-1 in the intervertebral disc. A histologic experimental model

STUDY DESIGN: Monocyte chemoattractant protein-1 was investigated in an experimental rat model using immunohistochemistry. OBJECTIVE: To ascertain the precise mechanism of macrophage recruitment in the early phase of disc resorption. SUMMARY OF BACKGROUND DATA: In previous studies, many investigators reported that disc herniation was resorbed by monocytic phagocytosis. However, how the recruitment of monocytes was triggered is still unknown. METHODS: The autologous intervertebral discs from tails of Wistar rats were subcutaneously implanted into the abdomen. These discs were obtained on days 2, 3, 7, and 14 after implantation and were used for immunohistochemical study and for quantitative analysis of monocyte chemoattractant protein-1 by sandwich enzyme-linked immunosorbent assay. RESULTS: Monocyte chemoattractant protein-1-positive granulocytes and macrophages were observed surrounding the intervertebral disc, and monocyte chemoattractant protein-1-positive disc chondrocytes were observed in the nucleus pulposus and the inner anulus fibrosus on day 3. By day 7, monocyte chemoattractant protein-1-positive and TRPM-3-positive macrophages appeared in the granulation tissue, and some of these cells invaded the nucleus pulposus and inner anulus fibrosus. The concentration of monocyte chemoattractant protein-1 was highest on day 3. CONCLUSION: Intervertebral disc chondrocytes have chemotactic properties and play an active role in the recruitment of monocytes involved in disc resorption.     

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.     

An atypical psoriatic spondylitis case, successfully treated with methotrexate

We present a 45-year-old male patient who was hospitalized with lumbar disc herniation and whose control magnetic resonance imaging (MRI) findings initially suggested brucella spondylitis. Definitive diagnosis, however, indicated psoriatic spondylitis and the patient was successfully treated with methotrexate. A diagnosis of lumbar disc herniation was made in May 1991, during his psoriasis vulgaris treatment. He was hospitalized in August 1994 with a complaint of low-back pain persisting over the last six months despite treatment with analgesics. He was evaluated by clinical, radiological, laboratory and scintigraphic methods, following control MRI findings suggesting infection of vertebral bodies, particularly pointing to brucellosis in addition to disc herniation. A diagnosis of psoriatic spondylitis was finally established and 7.5 mg methotrexate weekly was administered. Significant improvement was obtained of psoriatic skin lesions, low-back pain and MRI findings through a six-month treatment period.     

Distraction of lumbar vertebrae in gravitational traction

STUDY DESIGN: Experimental study of 30 patients diagnosed with low back pain resulting from lumbar disc herniation, disc degeneration, and segmental instability. Patients underwent gravitational traction, and widening of the intervertebral space and posterior facets was measured on radiographs. This same procedure was performed with a group of 30 healthy individuals. OBJECTIVES: To determine the effect of gravitational traction on the widening of the intervertebral space and the other vertebral structures in patients with low back pain and in healthy individuals. SUMMARY OF BACKGROUND DATA: Gravitational traction is performed by suspending the patient in a hanging, upright position for an extended period of time. In spite of disagreement among authors about the effect of lumbar traction, recent innovations have enabled the distraction of vertebrae. METHODS: A specially designed apparatus was used to apply gravitational traction. Pre- and post-traction radiographs were obtained to study the changes in the L2-L3, L3-L4, L4-L5, and L5-S1 intervertebral spaces; Ferguson's angle; L1-S1 total distance; and blood pressure. RESULTS: Distraction was more than approximately 3 mm in each intervertebral space in both groups. CONCLUSION: Gravitational traction had a very apparent effect on intervertebral space and was found to be an effective method to distract lumbar vertebrae. Discomfort experienced by the patient during suspension may be overcome by making biomedical changes to the suspension corset.     

Lumbar intervertebral disk herniation in children

A consecutive series of 16 children from 9 to 18 years old, with lumbar intervertebral disc herniation who were treated surgically in Department of Neurosurgery Medical Academy in Poznań, between 1978-1992, was analysed. The clinical symptoms, X-ray assessment, type of operation and outcome are reviewed. In our analysis characteristic features of disc herniation in children are: the onset of pain due to violent injury in relation to lifting, bilateral neurological symptoms and radiculography imaging central intervertebral disc herniation.     

A new culture system to study the metabolism of the intervertebral disc in vitro

STUDY DESIGN: This study determined whether entrapment of a rabbit intervertebral disc in alginate gel helped to promote the retention of normal metabolic activities by the nucleus pulposus and anulus fibrosus in tissue culture. OBJECTIVES: To establish an in vitro culture system to study the metabolism of the intervertebral disc as a whole integral organ. SUMMARY OF BACKGROUND DATA: In vitro studies of the metabolism of intervertebral discs have been scarce because of the difficulties involved in maintaining the integrity of the tissues, especially that of the nucleus pulposus, in culture medium. METHODS: Rabbit intervertebral discs were embedded in alginate gel and maintained in culture for as long as 1 month. At weekly intervals, experiments were performed to measure the rate of proteoglycan synthesis and to characterize proteoglycans newly synthesized by cells in the anulus fibrosus and nucleus pulposus. In addition, at these same time intervals, the contents of sulfated proteoglycans, antigenic keratan sulfate, hyaluronan, and collagen in these two intervertebral disc tissues were measured to evaluate tissue integrity. Intervertebral discs cultured in medium alone were used as controls and analyzed in parallel. RESULTS: The anulus fibrosus and nucleus pulposus of intervertebral discs cultured in alginate gel sustained a higher rate of proteoglycan synthesis and maintained a higher content of extracellular matrix components than the respective controls at all times. CONCLUSIONS: This new alginate tissue culture system should prove useful for studying the metabolism of whole intervertebral discs.     

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.     

Age-dependent correlation of low-back pain and lumbar disc regeneration

The prevalence of lumbar disc degeneration in subjects suffering from low-back pain (n = 207; age range 10-49 years) and in age-matched asymptomatic controls (n = 216) was investigated by magnetic resonance imaging. The percentage of subjects with degenerated discs increased with age; starting from the age of 15 years, this increase was more rapid in subjects with low-back pain. Concurrently, the number of degenerated discs was higher in the pain group than in controls. Lumbar disc degeneration manifests earlier and in a greater percentage of subjects with low-back pain than in asymptomatic controls.     

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.     

Sensory nerve fibres from lumbar intervertebral discs pass through rami communicantes. A possible pathway for discogenic low back pain

It has been thought that lumbar intervertebral discs were innervated segmentally. We have previously shown that the L5-L6 intervertebral disc in the rat is innervated bilaterally from the L1 and L2 dorsal root ganglia through the paravertebral sympathetic trunks, but the pathways between the disc and the paravertebral sympathetic trunks were unknown. We have now studied the spines of 17 rats to elucidate the exact pathways. We examined serial sections of the lumbar spine using immunohistochemistry for calcitonin gene-related peptide, a sensory nerve marker. We showed that these nerve fibres from the intervertebral disc ran through the sinuvertebral nerve into the rami communicantes, not into the corresponding segmental spinal nerve. In the rat, sensory information from the lumbar intervertebral discs is conducted through rami communicantes. If this innervation pattern applies to man, simple decompression of the corresponding nerve root will not relieve discogenic pain. Anterior interbody fusion, with the denervation of rami communicantes, may be effective for such low back pain.     

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.     

Neovascularization induced by anulus and its inhibition by cartilage endplate. Its role in disc absorption

STUDY DESIGN: A study of neovascularization with respect to the anulus and the endplate. OBJECTIVES: To determine the ability of the anulus and the endplate to induce neovascularization and to study the effect of the endplate on the neovascularizing activity of the anulus. SUMMARY OF BACKGROUND DATA: Previous studies showed that herniations contain varying amounts of nucleus pulposus, anulus fibrosus, and endplate. Results of recent studies have shown preferential neovascularization around the herniated anulus rather than the endplate. METHODS: Human L4-L5 discs were harvested from three specimens. In the left cornea of New Zealand White rabbits, an anulus (AF group) or an endplate (EP group) was implanted 4 mm from the superior corneoscleral limbus. In a third group (AF and EP group), an endplate was implanted between the anulus and the limbus. Twelve assays were done for each group. Sham surgeries were done on a fourth group as a control. Neovascularization was monitored by stereomicroscopy and scored from 0 (no neovascularization) to +5 (capillaries growing around the implant). Histologic studies were done at weekly intervals. RESULTS: In the AF group, the anulus induced neovascularization in 11 or 12 corneas. By the third week, the anulus appeared thinner, and the newly formed vessels regressed. In the EP group, only two corneas showed neovascularization; 10 corneas showed no vascularization. In the AF and EP group, three corneas showed no neovascularization, seven had sustained neovascularization, and two had vascularization. In the corneas containing the endplates, the implants remained unchanged. Control corneas did show vascularization. Histologic sections showed that neovascularization and cell infiltration were most abundant in the AF group, followed by the AF&EP and the EP groups. CONCLUSION: The reactions to anulus fibrosus and to cartilage endplate differ. Anulus fibrosus may contain soluble substances that induce neovascularization, leading to its degradation and absorption. Cartilage endplate fails to induce neovascularization or diminishes the neovascular response, preventing its degradation. Disc herniations that contain a significant amount of endplate may not be degraded nor absorbed, leading to failure in spontaneous remission of symptoms.