Relationships between outcomes of conservative treatment and magnetic resonance imaging findings in patients with mild cervical myelopathy caused by soft disc herniations.

STUDY DESIGN: A retrospective follow-up study of conservatively treated patients with mild cervical myelopathy caused by cervical soft disc herniation. OBJECTIVE: To investigate the outcome of conservative treatment for patients with mild myelopathy caused by cervical soft disc herniation and to evaluate usefulness of magnetic resonance findings in the prediction of the outcomes. SUMMARY OF BACKGROUND DATA: Recent studies on conservative treatment for cervical soft disc herniation have focused mainly on radiculopathy, and not on myelopathy. METHODS: Twenty-seven patients with mild cervical myelopathy secondary to cervical soft disc herniation were treated conservatively for more than 6 months by cervical bracing and restriction of daily activities. Of the 27 patients, 17 patients (Group A) underwent conservative treatment only and it was associated with improvement in their neurologic deficits, while the other 10 patients (Group B) ultimately underwent decompression surgery because of neurologic deterioration. Comparisons between the two groups were made in regard to JOA scores, patient satisfaction, and magnetic resonance findings, including location of the disc herniation (focal or diffuse in the sagittal plane, median or paramedian in the axial plane). RESULTS: The JOA scores were 13.6 +/- 1.6 in Group A and 14.1 +/- 1.6 in Group B before treatment, 14.9 +/- 1.0 and 12.9 +/- 2.1, respectively, at 3 months, and 16.2 +/- 0.8 and 16.0 +/- 1.2, respectively, at the final follow-up. The JOA scores at 3 months were significantly lower in Group B than in Group A. Satisfaction with the results of treatment at the final follow-up was reported by 77% of the patients in Group A and 90% in Group B. Focal-type herniation was present in 47% of the patients in Group A and 70% in Group B, while median-type herniation was diagnosed in 77% in Group A and 30% in Group B. Follow-up magnetic resonance imaging of the patients in Group A showed spontaneous regression of a herniated mass in 10 patients (59%). Diffuse-type herniations were more likely to regress spontaneously than focal-type herniations (78% vs. 37%). CONCLUSIONS: Conservative treatment is an effective treatment option for mild cervical myelopathy caused by cervical soft disc herniation. A good outcome can be expected in patients with a median-type and/or diffuse-type herniation on magnetic resonance imaging.     

Spontaneous resorption in recurrent intradural lumbar disc herniation. Case report

The authors report a case of spontaneous resorption of intradural disc material in a patient with recurrent intradural lumbar disc herniation and review magnetic resonance (MR) imaging and histopathological findings. Intradural lumbar disc herniation is rare, and most patients with this condition require surgical intervention due to severe leg pain and vesicorectal disturbance. In the present case, however, the recurrent intradural herniated mass had completely disappeared by 9 months after onset. Histological examination of intradural herniated disc tissue demonstrated infiltrated macrophages and angiogenesis within the herniated tissue, and Gd-enhanced MR images showed rim enhancement not only at the initial presentation, but also at recurrence. The authors conclude that when rim enhancement is present on Gd-enhanced MR images, there is a possibility of spontaneous resorption even though the herniated mass may be located within the intradural space. Moreover, when radiculopathy is controllable and cauda equina syndrome is absent, conservative therapy can be selected.     

Anterior or posterior approach of thoracic disc herniation? A comparative cohort of mini-transthoracic versus transpedicular discectomies

Background contextThe optimal surgical treatment of thoracic disc herniations remains controversial and depends on the consistency of the herniation and its location related to the spinal cord.PurposeTo compare the outcomes of patients with symptomatic thoracic disc herniations treated with anterolateral mini-transthoracic approach (TTA) versus posterior transpedicular discectomy.Study designThis is a prospective comparative cohort study.Patient sampleOne hundred consecutive patients with symptomatic thoracic herniated discs were operated by mini-TTA (56 patients) or transpedicular discectomy (44 patients).Outcome measuresNeurologic assessment by American Spinal Injury Association (ASIA) Impairment Scale and patients' self reported perceived recovery and complications.MethodsThe consistency and location of the herniated disc in relation to the spinal cord was evaluated by preoperative computed tomography and magnetic resonance imaging. Patients were assessed neurologically before surgery and at regular outpatient controls at 2 months or later. Long-term follow-up was achieved by questionnaires sent by mail.ResultsIn both groups, most patients had symptoms of myelopathy and radicular pain; patients who underwent mini-TTA, more frequently suffered from spasticity. Fifty-eight percent of the herniated discs were calcified and 77% were larger than one-third of the spinal canal. All patients presented with ASIA Grade C or D (64%) or ASIA Grade E (36%). Postoperatively, 50% of the patients treated with mini-TTA and 37% of the transpedicular group improved at least one grade on the ASIA scale (p=.19). The duration of surgery, blood loss, hospital stay, and complication rate were significantly higher in patients treated with mini-TTA and were mainly related to the magnitude and consistency of the herniated disc. At long-term follow-up, 72% of the mini-TTA patients reported good outcome versus 76% of the transpedicular discectomy group (p=.80).ConclusionsSurgical treatment of a symptomatic herniated disc contributed to a clinical improvement in most cases. The approach is dependent on the location, the magnitude, and the consistency of the herniated thoracic disc. Medially located large calcified discs should be operated through an anterolateral approach, whereas noncalcified or lateral herniated discs can be treated from a posterior approach as well. For optimal treatment of this rare entity, the treatment should be performed in selected centers.     

Long-term changes in the magnetic resonance image after chemonucleolysis

Summary After treatment of a symptomatic herniated disc with chymopapain, 14 patients were re-examined by magnetic resonance imaging (MRI) at a mean follow-up of 72 months. Well-defined MRI findings before chemonucleolysis were compared with those after the procedure by an independent observer. Five MRI parameters were assessed. No significant change was noted in the signal intensity of the affected disc, the extent of osteochondrosis and endplate reaction of the affected segment. The height of the affected disc as well as the size of the disc herniation were reduced significantly. The loss of the height is seen as a direct result of chymopapain activity, whereas the alteration of the size of the herniation seems to depend on the natural history of a disc herniation and is probably not a simple result of the treatment.     

Spontaneous regression of herniated cervical disc.

BACKGROUND CONTEXT: Spontaneous regression of herniated lumbar disc has been well established. However, spontaneous regression of herniated cervical disc is rare, and such reports are few. PURPOSE: To present a rare case of spontaneous regression of herniated cervical disc. STUDY DESIGN: A case study. METHODS: A 27-year-old man presented with severe pain on the left C6 level. Magnetic resonance imaging (MRI) revealed a lateral extruded disc at the C5-C6 level. The patient refused discectomy. RESULTS: The patient's pain disappeared after 3 weeks. Follow-up MRI revealed partial spontaneous regression in the extruded disc after 3 weeks and complete spontaneous regression after 12 months. CONCLUSION: All previous cases of herniated cervical disc that regressed spontaneously have been of the extruded type. In the patient with the cervical extruded disc, nonsurgical conservative observation should be considered an option for treatment.     

Effect of the transligamentous extension of lumbar disc herniations on their regression and the clinical outcome of sciatica

STUDY DESIGN: Magnetic resonance imaging of symptomatic herniated lumbar discs was investigated longitudinally and prospectively for the presence of tear in the posterior longitudinal ligament (PLL). OBJECTIVES: To clarify the effect of transligamentous extension through the PLL of herniated disc on its regression and to determine the factors contributing to a successful clinical outcome. SUMMARY OF BACKGROUND DATA: Greater regression of the herniated fragment has been noted with larger initial disc herniations. The exposure of herniated disc materials to the epidural vascular supply through the ruptured PLL has been suspected to play a part in the mechanism of disappearance of the herniated nucleus pulposus. However, it had not been shown clinically. METHODS: Clinical outcomes and magnetic resonance images of 36 patients with symptomatic lumbar disc herniations, treated conservatively, were analyzed. Patients were divided into three groups: subligamentous, transligamentous, and sequestered herniations. The size of the herniated disc was measured by herniation ratio, which is defined as the ratio of the area of herniated disc to that of the thecal sac on the axial view. Factors associated with the natural regression of herniated disc and the successful clinical outcome were explored. RESULTS: Of the 36 herniated discs, 25 decreased in size. Ten (56%) of 18 subligamentous herniations, 11 (79%) of 14 transligamentous herniations, and all 4 (100%) sequestered herniations were reduced in size. The average decreases in herniation ratio of the subligamentous, transligamentous, and sequestered disc groups were 17%, 48%, and 82% respectively. The decrease in herniation ratio was related to the presence of transligamentous extension but was not related to the initial size of herniation. Successful outcome correlated with a decrease in herniation of more than 20%. CONCLUSION: Transligamentous extension of herniated disc materials through the ruptured PLL is more important to its reduction in size than is the initial size of the herniated disc. Decrease in herniation ratio of more than 20% seems to correspond to successful clinical outcome.     

Functional results after anterior lumbar fusion at L5-S1 in patients with normal and abnormal MRI scans.

The debate continues as to which patient responds best to surgical versus nonsurgical intervention for painful degenerative disc syndrome. Discography is often used as the basis for that decision. In a review of 53 cases followed for an average of 20 months after surgery, only 50% of patients with type I (contained) discography and normal magnetic resonance imaging findings were found to be improved. In those patients with types II and III (noncontained) discography and abnormal magnetic resonance imaging scans, a 75% success rate was seen. There was an overall 80% fusion rate for all patients who underwent anterior lumbar fusion at L5-S1. Average age was 34 years, with average length of disability from low-back pain of 11 months. All patients were placed in a similar presurgery and postsurgery rehabilitation protocol and had failed nonsurgical treatment options. In this matched group of patients, those with abnormal magnetic resonance imaging scans and abnormal discography, clearly fared better, with a 75% percent success rate versus 50% success rate in those with normal magnetic resonance imaging findings. This series raises the question as to whether those patients with normal magnetic resonance imaging findings are surgical candidates.     

MRI classification of lumbar herniated intervertebral disc.

A consecutive series of 28 patients with lumbar herniated intervertebral disc (HIVD) who exhibited positive magnetic resonance imaging (MRI) findings was analyzed and compared with operative findings to define the type of disc herniation. This prospective study showed that the overall accuracy of MRI in predicting the types of HIVD was 80.6%. Proton density image was the most helpful in differentiating protruded discs from extruded ones. Disruption of "posterior longitudinal ligament line," defined on T2-weighted sagittal image, was reliable in differentiating a transligamentous disc from subligamentous one. Sequestered disc could be more accurately diagnosed with Gadolinium-DTPA enhancement, which showed anterior rim enhancement of the sequestered portion on T1-weighted axial image.     

The results of nucleoplasty in patients with lumbar herniated disc: a prospective clinical study of 52 consecutive patients.

BACKGROUND CONTEXT: Nucleoplasty is a minimally invasive, percutaneous procedure that uses radiofrequency energy to ablate nuclear material and create small channels within the disc. PURPOSE: To evaluate the efficacy of nucleoplasty technique in patients with leg pain caused by radicular encroachment. STUDY DESIGN/SETTING: A prospective clinical study of subjects with lumbar disc herniation, and radicular pain resistant to previous medical treatment and physiotherapy for a period of at least 3 months. PATIENT SAMPLE: Fifty-two consecutive patients with leg pain and magnetic resonance imaging evidence of small and medium-sized herniated discs correlating with the patient's symptoms (contained disc herniation<6 mm, with a disc height>/=50% in comparison to normal adjacent discs) were included. OUTCOME MEASURES: Visual analogue scale (VAS) was administered and Oswestry disability questionnaires were filled out at preprocedure and postprocedure 2 weeks, 6 months, and 1 year. Reduction of analgesic treatment and the patients' satisfaction were also recorded. METHODS: All procedures were performed under local anesthesia and fluoroscopic guidance on an outpatient basis. Patients underwent discography to evaluate annular integrity just before nucleoplasty. Channels were created in the nucleus by advancing the radiofrequency probe (ablating) and withdrawing it (coagulation). In all patients six channels were created. RESULTS: Thirty-four patients had one and 18 had two discs treated; a total of 70 procedures were performed. Mean age of patients was 44.8+/-8.6 years. The mean follow-up period was 12.1+/-1.6 months. Mean VAS reduced from preprocedure 7.5 to 3.1 at postprocedure 6 months and to 2.1 at the latest follow-up. Mean Oswestry index decreased from 42.2 to 24.8 at 6 months and to 20.5 at the latest examination. Analgesic consumption was stopped or reduced in 42 patients (85%) at 6 months and in 46 patients (94%) 1 year after the procedure. Overall patient satisfaction was 81% at 2 weeks, 85% at 6 months, and 88% at the latest follow-up. There were no complications related to the procedures. CONCLUSIONS: Our results encourage us to use nucleoplasty in carefully selected patients with leg pain caused by radicular encroachment. We recommend applying this minimally invasive technique only in those patients with small (<6 mm) contained disc herniations, with a disc height of>or=50% and with annular integrity.     

Correlation between a positive Hoffmann's reflex and cervical pathology in asymptomatic individuals

STUDY DESIGN: Asymptomatic patients with a positive Hoffmann's reflex were prospectively studied with cervical radiographs and magnetic resonance imaging. OBJECTIVES: To determine a relationship between a positive Hoffmann's reflex and cervical pathology in asymptomatic patients and to evaluate if further work-up was necessary in this patient population. SUMMARY OF BACKGROUND DATA: A positive Hoffmann's reflex usually implies an upper motor neuron lesion from spinal cord compression. Although this reflex is commonly tested, the significance of this reflex in asymptomatic patients is not known. METHODS: Sixteen patients without cervical pain or radiculopathy and a positive Hoffmann's reflex were prospectively studied with cervical radiographs and magnetic resonance imaging. Positive findings were correlated with a detailed neurologic examination. RESULTS: All 16 patients were asymptomatic. Fourteen patients (87.5%) demonstrated spondylosis on cervical radiographs. The magnetic resonance imaging studies showed pathologic findings in all 16 patients. Fifteen patients (94%) had cervical involvement with cord compression from a herniated nucleus pulposus. The remaining patient had a T5-T6 thoracic disc with resultant compression. No treatment was instituted, and the clinical course of each patient was not affected. CONCLUSIONS: Although the presence of cervical cord impingement is extremely high in these patients, no treatment was rendered specifically to address the cervical pathology. Therefore, the presence of a positive Hoffmann's reflex in asymptomatic patients strongly suggests underlying cervical pathology, but it does not warrant further evaluation with either cervical radiographs or magnetic resonance imaging since the management and clinical course are not affected by positive studies.     

Lumbar discography followed by computed tomography. Refining the diagnosis of low-back pain

Two hundred fifty patients with low-back pain who underwent lumbar discography followed by computed tomography (CT) are the subject of this prospective study. In 93% of the patients, these combined imaging techniques provided additional useful diagnostic information that affected patient management and the selection of treatment alternatives. Lumbar discography followed by CT proved valuable in determining the significance of equivocal or multiple level abnormalities, determining the type of disc herniation, defining surgical options, and evaluating the previously operated spine. In 94% of patients who had surgery, CT-discography correctly predicted the type of disc herniation as protruded, extruded, sequestrated, or internally disrupted. Computed tomography-discography may be more sensitive that magnetic resonance imaging (MRI) in the early stages of disc degeneration because 18 of 177 discs with a normal T2-weighted image were discographically abnormal and the CT-discogram revealed annular tears or radial fissuring. The radiographic morphology of the normal herniated and degenerative lumbar discs shown by CT-discography gives unique insight into the pathogenesis of disc degeneration. The complications that followed the 750 discograms were one case of urticaria and one disc space infection. Even with the availability of high resolution CT and MRI, lumbar discography remains the only pain provocation challenge to the lumbar disc.     

Spontaneous resolution of "protruded" lumbar discs.

Decreasing size of disc material that has herniated, whether "contained" or "protruded" has previously been described and sometimes this can be so complete that residual material is barely visible. In a retrospective clinical survey, from among almost 2180 consecutive patients admitted during 1994 - 2002 with low back pain; due to our low follow-up ratios and high price of the magnetic resonance imaging (MRI), only 42 patients with a lumbar disc protrusion could be found who had two MRI scans obtained at least five weeks apart. Among these, 4 patients were spotted with a totally resolved disc protrusion. T (2)-weighted MRI images were suggesting shrinkage due to dehydration and regression within the annulus of protruded disc fragments that had not fully migrated. Our patients are further examples for total resolution of the large "protruded" disc without any treatment; and since concomitant disc protrusions at other levels persisted, the resolution of these discs is supposed to be spontaneous.     

Magnetic resonance imaging and contrast CT of the lumbar spine. Comparison of diagnostic methods and correlation with surgical findings

Thirty-two patients with suspected lumbar disc herniation were studied with magnetic resonance imaging (MRI) and contrast computed tomography (CT). One hundred disc levels were evaluated. Twenty-five patients underwent surgery on 31 discs, allowing anatomic confirmation of the diagnosis. Surgical findings supported the MRI diagnosis at 28 of 31 levels (90.3% accuracy), whereas the CT diagnosis correctly reflected only 24 of 31 levels (77.4% accuracy). Discrepancy between MRI and CT interpretation occurred at ten levels that were surgically explored. Computed tomography (CT) was incorrect at seven levels, and MRI was in error at three levels. The sensitivity of MRI was 91.7%, compared with 83.3% for CT, and the MRI specificity of 100% was superior to 71.4% for CT. This study demonstrates the clinical superiority of surface coil MRI over contrast CT in the evaluation of lumbar disc herniation. Surface coil MRI can be used as the initial diagnostic procedure for a suspected herniated lumbar disc, using invasive contrast studies and CT, if required, to clarify an equivocal MRI finding.     

Disc herniation in cervical fracture subluxation

Previous reports of computed tomographic scan with contrast myelography in cervical spinal cord injury have shown a rate of disc herniation of less than 5%. We hypothesized that injuries associated with forces adequate to cause bone or ligamentous injury in the region of the disc space could be associated with higher and more significant rates of disc herniation. Thirty-seven consecutive traumatic midcervical fracture subluxations were reviewed. Fracture subluxation was defined by fracture of the facet joints, pedicles, or vertebral bodies or more than 3.5 mm subluxation from C2-C3 to C7-T1. Reduction was achieved in 97% and was not associated with neurological deterioration. On the basis of plain films, tomograms, and plain computed tomographic scans, the injuries were classified as flexion dislocation, flexion compression, compression burst, or extension injuries. Twenty-five computed tomographic scans with contrast myelograms and one magnetic resonance imaging scan were obtained. All patients with partial neurological deficits were studied. A herniated disc was defined as that which deformed the thecal sac and/or nerve roots. Retrospectively, a neuroradiologist reviewed the studies for the presence of herniated disc. Disc herniation was seen at the level of injury in 9 (35%) patients and not seen in other patients. Forty-seven percent of the patients with partial deficits had herniated discs. Herniated disc was seen most frequently in flexion dislocation and flexion compression injuries. Three patients (20%) with partial deficits underwent discectomy. Patients with partial spinal cord injury and discectomy, on average, improved more than other patients with partial spinal cord injury.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of angled sagittal MRI and conventional MRI in the diagnosis of herniated disc and stenosis in the cervical foramen

The object of this study is to demonstrate that angled sagittal magnetic resonance imaging (MRI) enables the precise diagnosis of herniated disc and stenosis in the cervical foramen, which is not available with conventional MRI. Due to both the anatomic features of the cervical foramen and the limitations of conventional MR techniques, it has been difficult to identify disease in the lateral aspects of the spinal canal and foramen using only conventional MRI. Angled sagittal MRI oriented perpendicular to the true course of the foramina facilitates the identification of the lateral disease. A review of 43 patients, who underwent anterior cervical discectomy and interbody fusion, is presented with a herniated disc and/or stenosis in the cervical foramen. They all had undergone conventional MRI and angled sagittal MRI. Fifty levels were surgically explored for evidence of foraminal herniated disc and stenosis. The results of each test were correlated with what was found at each explored surgical level. The sensitivity, specificity, and accuracy of both examinations for making the diagnosis of foraminal herniated disc and stenosis were compared. During the diagnosis of foraminal herniated disc, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.7, 95.0, and 96.0%, respectively, compared with 56.7, 85.0, and 68.0% for conventional MRI. In making the diagnosis of foraminal stenosis, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.3, 95.7, and 96.0%, respectively, compared with 40.7, 91.3, and 66.0% for conventional MRI. In the above groups, the difference between the tests for making the diagnosis of both foraminal herniated disc and stenosis was found to be statistically significant in sensitivity and accuracy. Angled sagittal MRI was a more accurate test compared to conventional MRI for making the diagnosis of herniated disc and stenosis in the cervical foramen. It can be utilized for the precise diagnosis of foraminal herniated disc and stenosis difficult or ambiguous in conventional MRI.     

percutaneous laser nucleotomy for lumbar disc herniation: Preliminary report of early results and MRI findings

Early therapeutic results and magnetic resonance imaging (MRI) findings were serially evaluated for 34 consecutive patients with lumbar disc herniation treated by percutaneous laser nucleotomy (PLN), a minimally invasive technique for reducing intradiscal pressure, in which a neodymium: yttrium-aluminum-garnet (Nd:YAG) laser was used. At the mean follow up 13.8 months after PLN, successful results were obtained in 20 patients (58.8%). No serious complications were encountered. In patients with contained discherniation, the improvement rate was significantly higher than that in patients with non-contained dise herniation (P<0.05). Sagittal magnetic resonance (MR) images obtained during the time sequence after PLN demonstrated a relationship between MR signal intensity patterns and clinical recovery. No measurable change in the size of the herniated mass was confirmed on axial images immediately after PLN, while, in contrast, reduced signal intensity inside the disc was observed in 12 of 20 patients with successful results in the early postoperative period. Postoperative T2-weighted MRI can be used to predict the prognosis of patients treated with PLN. This work was presented, in part, at the 68th Annual Meeting of the Japanese Orthopaedic Association, Yokohama, 9–11 April, 1995     

Anterior disc protrusion as a cause for abdominal symptoms in childhood discitis. A case report.

STUDY DESIGN: A case report on infectious spondylitis in a child who reported abdominal pain and whose magnetic resonance image revealed anterior herniation of disc space contents. OBJECTIVES: To correlate the direction of disc protrusion in infectious spondylitis with clinical manifestations. SUMMARY OF BACKGROUND DATA: Previous studies have correlated posterior protrusion of disc space contents in infectious spondylitis with a clinical presentation of back pain, paravertebral muscle spasm, hamstrings tightness, and radiculopathy. None has connected anterior herniation of disc phlegmon with abdominal pain. METHODS: In addition to plain radiography and bone scintigraphy, magnetic resonance imaging was used to confirm the diagnosis of infectious spondylitis in a 6-year-old child with abdominal pain. Regular review for 1 year included repeat magnetic resonance imaging at 3 months. RESULTS: Initial magnetic resonance imaging revealed characteristic changes associated with infectious spondylitis throughout the L5-S1 vertebra-disc-vertebra unit and anterior protrusion of the disc material and phlegmon. Magnetic resonance imaging at follow-up examination 3 months later demonstrated complete resolution of the disc herniation. CONCLUSION: Future magnetic resonance imaging studies should correlate direction of disc herniation with age and symptomatology to validate or improve classifications of infectious spondylitis, which presently include only the last two parameters.     

低温等离子射频消融治疗腰椎间盘突出症初步探讨

目的评价低温等离子刀射频消融术治疗腰椎间盘突出症的临床疗效。方法 2006年1月～2009年12月应用低温等离子射频消融治疗腰椎间盘突出症共44例,男20例,女24例;年龄30～52岁,平均40岁。局部麻醉,在C型臂引导下操作。共46个椎间隙：单间隙42例,双间隙2例。术后随访近期效果。结果全部病例均获得随访,随访时间6～48个月,平均24个月。VAS评分术前（8.40±0.50）分,术后1周（2.60±0.53）分,末次随访（2.80±0.34）分。Oswestry评分术前（59.00±1.90）分,术后1周（30.00±1.80）分,末次随访（34.00±1.50）分。各指标术后及末次随访时与术前比较有显著性差异（P〈0.05或P〈0.01）,而术后两次随访差异无统计学意义（P〉0.05）。患者满意度80%,无任何并发症。结论经皮低温等离子刀髓核消融术是治疗腰椎间盘突出症行之有效的方法,这种技术简单、微创、安全、疗效肯定。关键是选择合适的适应证。     

Three-level thoracic disc herniation: Case report and review of the literature

A rare case of three-level thoracic disc herniation with associated neurological impairment, including motor, sensor and urinary disturbances, is reported. The diagnosis and localization of the level of cord compression were mainly based on the clinical examination supported by the findings of magnetic resonance imaging and somatosensory evoked potentials. An anterolateral transthoracic approach at the uppermost affected level was selected for removal of all herniated discs, with the use of a surgical microscope; the resected rib was used for intervertebral fusion. An improvement in the patient's subjective and neurological condition was already apparent a few months after the operation, and solid fusion was roentgenographically found at all operated levels. The use of a surgical microscope allows complete removal of the herniated disc while avoiding wide vertebrectomy and associated iatrogenic damage to the spinal cord.     

Early experience with percutaneous lateral discectomy

Seventeen patients were treated by percutaneous lumbar discectomy for a herniated disc and sciatica. The criteria for inclusion in this series included: (1) a protruding disc in the lumbar area causing neural compression; (2) persistent sciatica; (3) failure of conservative treatment; (4) magnetic resonance imaging, computer tomographic, or myelographic confirmation of the protrusion; and (5) chronic low-back pain with definite evidence of a protruding disc at the appropriate level. The only contraindication to the procedure is the presence of an extruded fragment. There were ten male and seven female patients, with an average age of 40 years. The operation was performed under local anesthesia and by the method of Hijikata. Six cases were at L5-S1, nine at L4-L5, four at L3-L4, and one at L2-L3. Fourteen of 16 patients were relieved of their symptoms. One operation was aborted due to the inability to pass the cannula beneath arthritic facet joints. One complication occurred early while using general anesthetic. An L5 nerve root was injured, causing a permanent drop foot. Major possible complications include infection, nerve root injury, and vascular injury. The success rate with an average follow-up period of six and one-half months was 87.5%.