Migrated Lumbar Disc Herniation Research Articles

ANALYSIS OF THE RELIABILITY OF THE LEE CLASSIFICATION FOR LUMBAR DISC HERNIATIONS

ABSTRACT Objective To evaluate the intra- and interobserver reliability of the Lee et al. classification for migrated lumbar disc herniations. Methods In 2018, Ahn Y. et al. demonstrated the accuracy of this classification for radiologists. However, magnetic resonance images are often interpreted by orthopedists. Thus, a cross-sectional study was conducted by evaluating the magnetic resonance images of 82 patients diagnosed with lumbar disc herniation. The images were evaluated by 4 physicians, 3 of whom were spinal orthopedic specialists and 1 of whom was a radiologist. The intra- and interobserver analysis was conducted using the percentage of concordance and the Kappa method. Results The report of the classifications used by the four observers had a higher proportion of “zone 3” and “zone 4” type classifications in both evaluation moments. The most affected anatomical levels were L5-S1 (48.2%) and L4-L5 (41.4%). The intra- and interobserver concordance, when comparing both moments evaluation of the complementary examinations of the participants involved, was classified as moderate and very good. Conclusions Lee’s classification presented moderate to very good intra- and interobserver reliability for the evaluation of migrated lumbar disc herniation. Level of evidence II; Retrospective Study.

Biportal endoscopic discectomy for high-grade migrated lumbar disc herniation.

Although endoscopic procedures for lumbar disc herniation have improved greatly and offer many advantages, the indications are limited mostly to nonmigrated or low-grade migrated disc herniation. Endoscopic application in migrated disc herniation cases is still challenging and technically demanding. The goal in this study was to determine the feasibility of biportal endoscopic discectomy for removal of high-grade migrated disc herniation. A retrospective review was performed in 262 patients who had undergone biportal endoscopic discectomy after the diagnosis of lumbar herniated disc. According to preoperative MRI findings, disc herniation was classified into 5 zones based on the direction and distance from the disc space. Patients were divided into 2 groups-a high-grade migration group and a low-grade migration group. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI), visual analog scale (VAS), and modified Macnab criteria, and those outcomes and operation time were compared between the 2 groups. There were 10 patients with "high-grade up," 8 with "low-grade up," 98 with disc-level, 102 with "low-grade down," and 44 with "high-grade down" herniation, thereby yielding 54 patients in the high-grade group and 208 in the low-grade group. Demographic data for the 2 groups showed no significant difference. There was no significant difference between the 2 groups in ODI, VAS, and modified Macnab criteria. Operation time between the 2 groups was not significantly different (60.74 vs 65.63 minutes, p > 0.05). Biportal endoscopic discectomy can be effective for high-grade migrated lumbar disc herniation with no prolonged operation time and satisfactory clinical outcomes.

Percutaneous Endoscopic Transforaminal Decompression in the Treatment of Patients with Migrated Lumbar Disc Herniation: A Retrospective Study

We aimed to discuss the surgical strategies, safety and clinical efficacy of percutaneous endoscopic transforaminal decompression for the treatment of patients with migrated lumbar disc herniation. This is a retrospective study. From May 2014 to April 2017, a total of 56 patients (32 men and 24 women) with migrated lumbar disc herniation were operated on by percutaneous endoscopic decompression via transforaminal approach. All enrolled patients had clinical symptoms with radiculopathy, and were identified as single-level, soft herniated disc by computed tomography and magnetic resonance imaging. Clinical efficacy were evaluated chiefly by leg pain visual analogue scale score, Oswestry disability index score, and modified MacNab criteria. Patients were all successfully treated by percutaneous endoscopic transforaminal decompression, with an mean operation time of 63 ± 12 minutes. The patients were followed up for a mean duration of 15 ± 2.7 months (range 12-18 months). The leg pain visual analogue scale score was dropped from 8.2 ± 1.9 preoperatively to 2.4 ± 1.5, 2.2 ± 1.3, and 1.8 ± 1.1 at 1, 6, and 12 months after the operation, respectively. Similarly, the Oswestry disability index score was also decreased from 62.4 ± 8.2 preoperatively to 18.4 ± 6.2, 12.6 ± 5.1, and 9.2 ± 3.4 at 1, 6, and 12 months postoperatively. There were 38 excellent cases, 13 good cases, and 5 fair cases by the assessment method of modified MacNab criteria at 12 months after the operation, with an excellent and good rate of 91.07%. Two cases were complicated with low extremity numbness, which were recovered by conservative treatment in 3 weeks. No persistent neurological deficit or infection occurred in this group postoperatively. We consider that percutaneous endoscopic decompression via transforaminal approach provided a safe, effective and minimally invasive alternative for the treatment of patients with migrated lumbar disc herniation.

Percutaneous Endoscopic Spine Surgery for Extruded Lumbar Disc Herniation

The conventional open discectomy is the gold standard for treating extruded lumbar disc herniation, especially in highly migrated lumbar disc herniation. Endoscopic spine surgery is known to be very challenging and technically demanding, in particular for highly migrated disc herniation. However, several studies have reported numerous effective techniques with results approximatively equal to conventional open surgeries or mini-open surgery. In the last few years, an increased number of endoscopic spine surgical techniques have been proposed in order to overcome various issues encountered in traditional endoscopic spine surgery. Nevertheless, surgical approach selection for treating extruded lumbar disc herniation is based on aspects such as anatomical structures, availability of surgical instruments, surgeon’s experience, and the disc herniation location. Advances in endoscopic visualization and instrumentation, as well as an increased demand for minimally invasive procedures, have led to the popularity of Percutaneous Endoscopic Lumbar Discectomy (PELD). PELD is a recent and advanced technique among other minimally invasive spine surgeries (MIS). It includes various kinds of surgical techniques to treat lumbar disc herniation and aims to offer a safe, less invasive surgical procedure for lumbar disc space decompression and removal of nucleus pulposus.

Percutaneous endoscopic lumbar discectomy via adjacent interlaminar space for highly down-migrated lumbar disc herniation: a technical report

The treatment of highly migrated lumbar disc herniation (LDH) is a challenge for percutaneous endoscopic lumbar discectomy (PELD). The purpose of this study was to determine the feasibility and efficacy of PELD for highly migrated LDH via the adjacent interlaminar space. We performed PELD via the adjacent interlaminar space in three patients with radiculopathy caused by highly migrated LDH using a full-endoscopic system (diameter of working channel: 4.1 mm, outer diameter: 6.9 mm). One case had a large interlaminar bone window that did not require enlargement. Enlargement of the bone window in other cases was performed with a 3.5-mm diameter high-speed drill. After the operation, we confirmed pain relief and evacuation of migrated LDH on magnetic resonance imaging in all patients. The mean operative time was 75.3 min, and no complication was observed. PELD via the adjacent interlaminar space is an appropriate operative approach for highly down-migrated LDH. Minimal laminectomy using a high-speed drill is conductive to this approach.

Treatment of migrated lumbar disc herniation with percutaneous endoscopic lumbar discectomy and target foraminoplasty

To evaluate the clinical outcome of percutaneous endoscopic lumbar discectomy with target foraminoplasty in treating migrated lumbar disc herniation. From June 2015 to January 2016, 25 patients with migrated lumbar disc herniation were treated with percutaneous endoscopic lumbar discectomy with target foraminoplasty. A total of 14 males and 11 females, aging from 23 to 52 years old (average: 37.6) were enrolled in this study. Discectomy occurred in L₂,₃ of 1 case, L₃,₄ of 3 cases, L₄,₅ of 12 cases, L₅S₁ of 9 cases. Preoperative, 1-week and 1-year postoperative visual analogue scale (VAS) scores were collected to evaluate lower back and leg pain; Oswestry Disability Index(ODI) was used to assess the lumbar function. All the patients were followed up for 12 to 19 months with an average of 15.2 months. The mean operation time was 108.6 min. No injury of dura, nerve root, or wound infection were found. Preoperative, 1-week and 1-year postoperative visual analogue scale(VAS) scores of lower back pain were 5.8±0.5, 2.5±0.4, 0.9±0.2, respectively, with significant differences among each other(P<0.05);VAS scores of leg pain were 7.1±0.6, 1.5±0.4, 0.7±0.6, respectively, with significant differences among each other(P<0.05). Lumbar ODI scores were 69.2±1.8, 22.5±4.7, 10.2±2.4 at the above time points and showed significant differences among each other(P<0.05). Percutaneous endoscopic lumbar discectomy with target foraminoplasty for migrated lumbar disc herniation showed advantages of less injuries, bleeding and complication. It also promotes rapid recovery, being curative safely and effectively.

Epiduroscopic laser neural decompression as a treatment for migrated lumbar disc herniation

Objective:Epiduroscopic laser neural decompression (ELND) is one of the more invasive techniques for managing patients with herniated lumbar disc. However, ELND can be used to treat, and diagnose the epidural pathology; indications for ELND remain controversial, especially, when applied in cases of large disc extrusion and migrated disc. This paper reports cases of patients that were satisfied with the ELND procedure for migrated lumbar disc herniation.Methods:We reviewed the medical records of patients that received ELND for migrated lumbar disc in an outpatient clinic. The patients complained of low back pain with radicular pain with an intensity over 5 on a numeric rating scale (NRS) that had persisted for over 1 month. The Magnetic resonance imaging (MRIs) showed migrated lumbar disc herniation, and patients opted for ELND because they had previously experienced nerve blocks, and did not want to receive open surgery for their pain, even after the limitations of ELND were explained.Results:Patients reported that their pain was dramatically reduced, and other discomfort symptoms, such as numbness, were also reduced after the procedure. In follow-up, all of the patients were satisfied with the results.Conclusion:We applied the ENLD procedure to mechanically, remove disc material that compressed the spinal nerve, and the patients were satisfied, and reported symptom relief. ELND was a sufficient treatment approach for lumbar migrated herniated disc for patients who did not want to undergo open spine surgery.

Suprapedicular Circumferential Opening Technique of Percutaneous Endoscopic Transforaminal Lumbar Discectomy for High Grade Inferiorly Migrated Lumbar Disc Herniation.

Purpose To evaluate the efficacy of suprapedicular circumferential opening technique (SCOT) of percutaneous endoscopic transforaminal lumbar discectomy (PETLD) for high grade inferiorly migrated lumbar disc herniation. Material and Methods Eighteen consecutive patients who presented with back and leg pain with a single-level high grade inferiorly migrated lumbar disc herniation were included. High grade inferiorly migrated disc was removed by the SCOT through PETLD approach. Outcome evaluation was done with visual analog scale (VAS) and Mac Nab's criteria. Result There were 14 males and 4 females. The mean age of patients was 53.3 ± 14.12 years. One, 4, and 13 patients had disc herniation at L1-2, L3-4, and L4-5 levels, respectively, on MRI, which correlated with clinical findings. The mean follow-up duration was 8.4 ± 4.31 months. According to Mac Nab's criteria, 9 patients (50%) reported excellent and the remaining 9 patients (50%) reported good outcomes. The mean preoperative and postoperative VAS for leg pain were 7.36 ± 0.73 and 1.45 ± 0.60, respectively (p < 0.001). Improvement in outcomes was maintained even at final follow-up. There was no complication. Conclusion In this preliminary study we achieved good to excellent clinical results using the SCOT of PETLD for high grade inferiorly migrated lumbar disc herniation.

Percutaneous endoscopic interlaminar lumbar discectomy for high-grade inferiorly migrated L5-S1 disc: A case report with technical review

L5-S1 disc has always been a difficult disc to target by rigid endoscope because of anatomical limitations. In this study, we have described the technique to overcome difficulty faced during endoscopic disc decompression of high-grade inferior migrated disc at L5-S1. We performed percutaneous endoscopic inter-laminar lumbar discectomy (PEILD) for removal of high grade inferiorly migrated disc and preserved the functional structures. After institutional review board approval, details of the patient with high-grade inferior migration at L5-S1 disc were reviewed. The patient was operated by a single specialist with use of the percutaneous endoscopic inter-laminar technique for high-grade inferior migrated extruded disc. Description of our technique & result is the focus of this study. The average VAS score was reduced from 9 pre-operatively to 3 post-operatively & to 1-2 within 2 weeks. Post-operative plantar flexion of foot improved from 2 to 4 immediately and up to 5 within 2 weeks. Ankle jerk reflex improved from 1+ to 2+. The pain severity score on BPI reduced from 9 to 3 postoperatively. Post-operative MRI showed that the high grade inferiorly ruptured disc had been successfully removed. We obtained excellent results in treating inferior extruded disc at L5-S1 using endoscopic inter-laminar approach. Inter-laminar endoscopic discectomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a high grade inferior migrated lumbar disc herniation.

Grading system for migrated lumbar disc herniation on sagittal magnetic resonance imaging: an agreement study.

Migrated lumbar disc herniations (LDHs) in the sagittal plane are common. Disc migration grading can be applied as a useful measurement tool in the diagnosis, treatment, and outcome evaluation of migrated LDH. No study has evaluated the reliability of migrated LDH grading. We evaluated the reliability and functionality of the current magnetic resonance imaging (MRI) grading system for migrated LDH. We assessed a six-level grading system developed based on sagittal MRI and graded according to the direction (rostral and caudal) and degree (low, high, and very high) of disc migration. One-hundred and one migrated LDHs treated with minimally invasive endoscopic discectomy were analyzed independently by two experienced radiologists. Intraobserver and interobserver agreements were assessed by kappa statistics. The most common migrated LDH grade was grade 4 (30.94%; caudal, low-grade migration). Rostral and caudal migrations were more common in the upper and lower lumbar levels, respectively. Interobserver agreement in the grading of migrated LDH was good at both the first (kappa=0.737) and second assessment (kappa=0.657). The intraobserver agreement for reader 1 was very good (kappa=0.827) and for reader 2 was good (kappa=0.620). The current grading system for migrated LDH was found to be reliable and functional with good interobserver and intraobserver agreement. It may be useful in the interpretation of disc migration patterns and outcomes of various minimally invasive surgical procedures.

Percutaneous Endoscopic Lumbar Discectomy for Highly Migrated Lumbar Disc Herniation

Percutaneous endoscopic lumbar discectomy (PELD) has been growing in popularity for the treatment of lumbar disc herniation (LDH) due to its irreplaceable advantages over conventional open surgery. Compared with common lumbar disc herniations, discectomy of highly migrated LDH by PELD is known to be very difficult. Highly migrated lumbar disc herniation has long been a challenge for its specific characteristics. Three approaches for PELD have been applied to access a highly migrated LDH, including an interlaminar approach (IL), transforaminal approach (TF), and contralateral transforaminal approach (CTF). However, none of the existing research has systematically described the selection of the most appropriate procedure from the 3 approaches or the individualization of an operative procedure in different cases. The purpose of this study was to present a detailed surgical approach selection and individualization of procedure in the treatment of highly migrated LDH with PELD. We also mean to compare the outcomes of patients with highly migrated LDH treated with PELD by the 3 approaches. Single-center retrospective observational study. An interventional pain management practice, a medical center, major metropolitan city, China. In our retrospective analysis between March 2011 and March 2013, 73 patients with single level highly migrated LDH received PELD. Clinical outcomes were assessed with the visual analogue scale (VAS) score, the modified MacNab criteria, and the Oswestry disability index (ODI). Relevant data such as operation duration and fluoroscopy frequency of the 3 operative approaches were recorded. The mean operating time of IL was 56 minutes, compared with 64 minutes for TF and 112 minutes for CTF. The mean intraoperative fluoroscopy times were 5.5 for IL, 9.7 for TF, and 14.6 for CTF. In each group, the mean VAS and ODI after surgery and 3 months after surgery improved dramatically compared with preoperative counterparts. However, the difference between postoperative results and the results 3 months after surgery was not significant (P > 0.05). The overall excellent rate was 90.4% according to the modified MacNab criteria; there was no significant statistical difference between the 3 operative routes. Operative complications occurred in 3 patients (2 after IL and one after CTF, 3 of 73, 4.1%). This study is limited by its sample size. In our research, PELD with all 3 approaches was similarly effective to highly migrated disc herniation. The CTF approach required the longest operation duration and the most intraoperative times. On the contrary, the least operation time and radiographfrequency was required with the IL approach. In addition, we came to a conclusion of surgery approach selection when it comes to varied HM-LDH. Key words: Highly migrated, lumbar disc herniation, percutaneous endoscopic lumbar discectomy, minimally invasive treatment.

Transforaminal percutaneous endoscopic lumbar discectomy for very high-grade migrated disc herniation

ObjectivesTransforaminal percutaneous endoscopic lumbar discectomy (PELD) for high-grade migrated disc herniation has been regarded as a challenging task, but because of the remarkable improvement in navigable instruments and advanced epiduroscopic technique, it can be used for the treatment of high- or very high-grade migrated disc herniation. The purpose of this study was to describe in detail the standardized technique of transforaminal PELD for very high-grade migrated disc herniation and demonstrate the clinical results. MethodsVery high-grade lumbar migrated disc herniation was defined as a disc migration beyond the inferior margin of the pedicle. Thirteen consecutive patients with very high-grade lumbar migrated disc herniation were treated with transforaminal PELD, which has three stages: (1) direction-oriented transforaminal approach, (2) release of periannular anchorage, and (3) epiduroscopic fragmentectomy with navigable instruments. The surgical outcomes were assessed using the visual analogue pain score (VAS), Oswestry disability index (ODI), and modified Macnab criteria. ResultsThe operated levels were L3-4 in 2 (15.4%) patients, L4-5 in 10 (76.9%), and L5-S1 in 1 (7.7%). The directions of migration were cranial in 8 patients and caudal in 5. The mean VAS for leg pain improved from 7.86±1.28 preoperatively to 2.54±1.51 at 6 weeks postoperatively and 1.85±1.07 at 1year postoperatively (P<0.01). The mean preoperative ODI improved from 84.92±6.36 preoperatively to 27.83±7.34 at 6 weeks postoperatively and 17.54±13.40 at 1year postoperatively (P<0.01). Excellent or good global outcomes were obtained in 84.6%, and the rate of symptomatic improvement was 92.3%. ConclusionTransforaminal PELD can be effective for very high-grade migrated lumbar disc herniation, and a standardized technique may provide a reliable and reproducible result.

Spontaneous Resolution of Sequestrated Lumbar Disc Herniation: A Prospective Cohort Study

Objective Spontaneous regression of sequestrated lumbar disc well known entity. But, the current reports about this scenario are confined to case reports or small case series. To assess the chance of complete spontaneous resolution of sequestrated lumbar disc herniation and to report the outcome of regressed cases in a prospective study. Method From January 2010 to July 2015, 103 patients with acute lower limb mono-radiculopathy, but without neurological motor deficit secondary to a migrated lumbar disc herniation thought to be a sequestrated free disc fragment were prospectively studied for the possibility of their spontaneous regression with time. All the qualified patients initially fulfilled the study criteria. But seven patients were lost to follow up and 9 more cases preferred to do surgery within a few days to three weeks after clinical trial. Eighty seven patients remained for clinical evaluation and periodic magnetic resonance imaging for the possibility of spontaneous regression. These patients include 39 males and 48 females. The age of the patients ranged from 22 to67 years with the mean of 42.96, SD= 10.65. Results In 75 of these cases complete resolution of the offending disc occurred. This was associated with marked improvement or even disappearance of pain intensity in short and mid-term follow-up. Furthermore, where a case of same level contralateral disc herniation was seen, not a single case of same level same side recurrence could be encountered. The cost of treatment and work status of the patients were significantly better than surgically treated patients according to previously published reports. In mid-term follow, recovery rate (McNab Criteria %) of these 75 patients was either good or excellent. All these were satisfied and recommend this type of treatment for similar patients. The remaining 12 patients, ultimately underwent surgery. Surprisingly, all had subligamentous location Conclusion This study clarifies that conservative management might be considered as an appropriated cost-effective option in treatment of sequestrated lumbar disc herniation in the patients with minimal neurological impairment, with probably high chance of spontaneous regression of the offending disc. However, to compare conservative versus surgery, in this sub-type of disc herniation, further clinical trials are recommended.

Epiduroscopic Assisted Percutaneous Endoscopic Lumbar Discectomy: A Technical Report

The Authors report a new technique with trans sacral epiduroscopy assisted Percutaneous Endoscopic Lumbar Discectomy (PELD) for high grade centrally down migrated lumbar disc herniation. When the chances of missing the disc fragments are high, as in the cases of down migrated disc herniations by conventional transforaminal PELD, it can be assisted by sacral epiduroscopy for the complete removal and confirmation of any remnant disc fragments.

Surgical Outcome of Two-Level Transforaminal Percutaneous Endoscopic Lumbar Discectomy for Far-Migrated Disc Herniation.

Objective. To describe the two-level percutaneous endoscopic lumbar discectomy (PELD) technique in transforaminal approach for highly migrated disc herniation and investigate its clinical outcomes. Methods. A total of 22 consecutive patients with highly migrated lumbar disc herniation were enrolled for the study from June 2012 to February 2014. Results. There were 12 males and 10 females, with a mean age of 41.1 (range 23–67) years. The mean follow-up period was 18.05 (range 14–33) months. According to the modified MacNab criteria, the clinical outcome at the final follow-up was excellent in 14, good in 6, and fair in 2 patients and the satisfactory rate (excellent and good) was 90.9%. The improvements in VAS and ODI were statistically significant. One patient had recurrent herniation in 18 months after the first surgery and underwent open discectomy. One patient showed symptoms of postoperative dysesthesia (POD), but the POD symptom was transient and partial remission was achieved in two months after conservative treatment. Conclusion. Two-level PELD in transforaminal approach can be a safe and effective procedure for highly migrated disc herniation.

Translaminar Microendoscopic Herniotomy for Cranially Migrated Lumbar Disc Herniations Encroaching on the Exiting Nerve Root in the Preforaminal and Foraminal Zones

Study DesignCase series.PurposeThe aim of this study was to describe translaminar microendoscopic herniotomy (TL-MEH) for cranially migrated lumbar disc herniations encroaching on the exiting nerve root in the preforaminal and foraminal zones and to report preliminary results of the procedure.Overview of LiteratureConventional interlaminar approaches for preforaminal and foraminal lumbar disc herniations result in extensive removal of the lamina and facet joint to remove disc fragments safely. More destructive approaches increase the risk of postoperative segmental instability.MethodsTL-MEH is a minimally invasive procedure for herniotomy via the translaminar approach using a microendoscopic technique. TL-MEH was performed in seven patients with a cranially migrated lumbar disc herniation encroaching on the exiting nerve root. The disc fragments were located in the preforaminal zone in four patients, and in the preforaminal and foraminal zones in three.ResultsAll patients experienced immediate relief from symptoms after surgery and satisfactory results at the final follow-up. Surgical complications, such as a dural tear, nerve injury, and surgical site infection, were not investigated.ConclusionsTL-MEH seemed to be an effective and safe alternative minimally invasive surgical option for patients with a cranially migrated lumbar disc herniation encroaching the exiting nerve root in the preforaminal and foraminal zones.

Full endoscopic contralateral transforaminal discectomy for distally migrated lumbar disc herniation

BackgroundDiscectomy of distally, inferiorly migrated disc herniations below midpedicle level of the vertebral body in the lower lumbar spine is known to be very difficult by endoscopy. The purpose of this study was to introduce the technical possibility of percutaneous endoscopic lumbar discectomy using a contralateral transforaminal approach for distally migrated disc herniation. MethodsWe reviewed 12 patients who underwent percutaneous endoscopic lumbar discectomy using the contralateral transforaminal approach for distally migrated disc herniation. Complete removal was verified through postoperative magnetic resonance imaging (MRI) follow-up in all patients. Mean follow-up was 25 months. ResultsClinical results according to MacNab criteria were excellent in ten patients and good in two. Average visual analogue scale for lower back pain and radicular pain improved from 6.8 and 8.2 preoperatively to 1.5 and 1.4, postoperatively (p < 0.01, respectively). ConclusionPercutaneous endoscopic lumbar discectomy using contralateral transforaminal approach can be a useful method in patients with distally migrated disc herniation, and endoscopic navigation of anterior epidural space from the contralateral foramen in the lower lumbar spine is technically possible.

２根障害を呈した遊走ヘルニアに対する内視鏡下手術の小経験

２根障害を呈した遊走ヘルニアに対する内視鏡下手術の小経験

Operative short-term results of migrated lumbar disc herniation

Operative short-term results of migrated lumbar disc herniation

A Migrated Lumbar Disc Herniation Simulating a Dumbbell Tumor

We report a case of a migrated lumbar disc hemiation, which on magnetic resonance imaging (MRI) simulated a dumbbell tumor in a 44-year-old woman who had severe pain in her right buttock and leg. A large epidural mass mimicking a dumbbell tumor was detected at the L5 vertebral level by MRI and computed tomography over myelography. Surgical fenestration of the L4/L5 interlaminar space revealed a dorsolateral epidural mass connected to the L5/S1 intervertebral disc extending laterally through the right L5/S1 intervertebral foramen. Histologically, it was degenerative disc material without active inflammation. Reevaluation of the MRI suggested some clues that might be useful in differentiating such a herniated disc from an epidural tumor.