Bupivacaine pleural effusion mimicking a hemothorax after a thoracoscopic microdiscectomy with epidural anesthesia.

PURPOSE: Post-operative pain after video-assisted thoracoscopic surgery is often treated using thoracic epidural analgesics or thoracic paravertebral analgesics. This article describes a case where a thoracic disc herniation is treated with a thoracoscopic microdiscectomy with post-operative thoracic epidural analgesics. The patient developed a bupivacaine pleural effusion which mimicked a hemothorax on computed tomography (CT). METHODS: The presence of bupivacaine in the pleural effusion was confirmed using a high performance liquid chromatography method. RESULTS: The patient underwent a re-exploration to relieve the pleural effusion. The patient showed a long-term recovery similar to what can be expected from an uncomplicated thoracoscopic microdiscectomy. CONCLUSION: A pleural effusion may occur when thoracic epidural analgesics are used in patents with a corridor between the pleural cavity and epidural space.

Posterolateral approaches to the thoracic spine for calcific disc herniation: is wider exposure always better?

OBJECTIVE: To compare the costotransversectomy (CTV) and transpedicular (TP) approaches versus the transfacet (TF) approach for the surgical treatment of calcific thoracic spine herniations (cTDH), in terms of surgical and clinical outcomes. BACKGROUND: Surgical approaches for cTDH are debated. Anterior approaches are recommended, while posterolateral approaches are preferred for non-calcific, paramedian, and lateral hernias. Currently, there is limited evidence about the superiority of a more invasive surgical approach, such as CTV or TP, over TF, a relatively less invasive approach, in terms of neurological outcome, pain, and surgical complications, for the treatment of cTDH. METHODS: A retrospective, observational, monocentric study was conducted on patients who underwent posterolateral thoracic approaches for symptomatic cTDH, between 2010 and 2023, at our institute. Three groups were drafted, based on the surgical approach used: TF, TP, and CTV. All procedures were assisted by intraoperative CT scan, spinal neuronavigation, and intraoperative neuromonitoring. Analyzed factors include duration of surgery, amount of bone removal, intraoperative blood loss, CSF leak, need of instrumentation for iatrogenic instability, degree of disc herniation removal, myelopathy recovery. Afterwards, a statistical analysis was performed to investigate the bony resection of the superior posterior edge of the vertebral soma. The primary outcome was the partial or total herniation removal. RESULTS: This study consecutively enrolled 65 patients who underwent posterolateral thoracic surgery for cTDH. The TF approach taking the least, and the CTV the longest time (p < 0.01). No statistical difference was observed between the three mentioned approaches, in terms of intraoperative blood loss, dural leakage, post-resection instrumentation, total herniation removal, or myelopathy recovery. An additional somatic bony resection was successful in achieving total herniation removal (p < 0.01), and the extent of bony resection was directly proportional to the extent of hernia removal (p < 0.01). CONCLUSIONS: No statistically significant differences were highlighted between the TP, TF, and CTV regarding the extent of cTDH removal, the postoperative complications, and the neurological improvement. The described somatic bone resection achieved significant total herniation removal and was directly proportional to the preop against postop anteroposterior diameter difference.

Percutaneous transforaminal endoscopic discectomy for Upper Lumbar Disc Herniation versus lower lumbar disc herniation: clinical outcomes and technical consideration.

BACKGROUND: Upper lumbar disc herniation (ULDH) accounts for 1-10% of all lumbar disc herniations (LDH). This study aimed to evaluate the clinical characteristics and outcomes of patients with ULDH who underwent percutaneous transforaminal endoscopic discectomy (PTED) compared with those with lower LDH. METHODS: 60 patients with ULDH or L4-L5 LDH treated with PTED between May 2016 and October 2021. MacNab criteria, visual analog scale (VAS) of back pain and leg pain, and Japanese Orthopedic Association (JOA) were evaluated before and after surgery. RESULTS: In the L1-L3 group, 59.1% of the patients had a positive femoral nerve tension test, and 81.8% of the patients had a sensory deficit. Both groups showed significant improvements in VAS scores for low back and leg pain, and JOA scores postoperatively. No significant differences in the degree of improvement were observed between the two groups. The excellent/good rate was 81.8% in the L1-L3 group and 84.2% in the L4-L5 group, showing no significant difference. CONCLUSION: PTED has comparable efficacy in treating ULDH as it does in treating lower LDH, it is a safe and effective treatment method for ULDH.

Full-Endoscopic Lumbar Discectomy: Tips & Tricks for New Users Based on a Retrospective Observational Study of the First 100 Patients.

AIM: To report our institutional experience with full-endoscopic lumbar discectomy (FELD) and analyzed the pertinent literature. MATERIAL AND METHODS: We retrospectively enrolled 100 patients who had undergone full-endoscopic discectomy for lumbar disc herniation using either an interlaminar (IL) or transforaminal (TF) approach. All patients underwent pre-operative imaging. Before and after surgery, patients' pain and disability levels were measured using visual analog scale (VAS) and Oswestry disability index (ODI) respectively. Clinical outcomes were assessed using the modified MacNab criteria. Patients were divided into two groups, Group 1 (cases 1-50) and Group 2 (cases 51-100), and their learning curve factors were compared using a Student's t-test. RESULTS: Sixtynine cases were operated via an IL approach and the remaining 31 cases using a TF approach. There were 4 early conversions in microdiscectomy. The mean operative time of the 96 procedures was 57 min. In Group 1, the mean operative time was 61.7 minutes (range: 35-110); in Group 2, it was 52.3 minutes (range: 25-75). The difference between the two groups was statistically significant (p=0.009). No significant differences were found in conversions, early operations, and recurrences between Groups 1 and 2. Both groups experienced a significant reduction in postoperative VAS and ODI compared to preoperative scores. CONCLUSION: The findings support previously reported information on the safety and effectiveness of the FELD. Herein, we share some practical tips and tricks based on our initial experience and on the review of the available literature, which could facilitate new users. In experienced hands endoscopic techniques make treatment of herniated discs feasible independently of patient age, anatomy, and/or targeted pathology features. Conversely, thoughtful patient selection and careful preoperative planning are highly recommended for new users.

Surgical Treatment of Calcified Thoracic Herniated Disc Disease via the Transthoracic Approach with the Use of Intraoperative Computed Tomography (iCT) and Microscope-Based Augmented Reality (AR).

Background and Objectives: The aim of this study is to present our experience in the surgical treatment of calcified thoracic herniated disc disease via a transthoracic approach in the lateral position with the use of intraoperative computed tomography (iCT) and augmented reality (AR). Materials and Methods: All patients who underwent surgery for calcified thoracic herniated disc via a transthoracic transpleural approach at our Department using iCT and microscope-based AR were included in the study. Results: Six consecutive patients (five female, median age 53.2 ± 6.4 years) with calcified herniated thoracic discs (two patients Th 10-11 level, two patients Th 7-8, one patient Th 9-10, one patient Th 11-12) were included in this case series. Indication for surgery included evidence of a calcified thoracic disc on magnet resonance imaging (MRI) and CT with spinal canal stenosis of >50% of diameter, intractable pain, and neurological deficits, as well as MRI-signs of myelopathy. Five patients had paraparesis and ataxia, and one patient had no deficit. All surgeries were performed in the lateral position via a transthoracic transpleural approach (Five from left side). CT for automatic registration was performed following the placement of the reference array, with a high registration accuracy. Microscope-based AR was used, with segmented structures of interest such as vertebral bodies, disc space, herniated disc, and dural sac. Mean operative time was 277.5 ± 156 min. The use of AR improved orientation in the operative field for identification, and tailored the resection of the herniated disc and the identification of the course of dural sac. A control-iCT scan confirmed the complete resection in five patients and incomplete resection of the herniated disc in one patient. In one patient, complications occurred, such as postoperative hematoma, and wound healing deficit occurred. Mean follow-up was 22.9 ± 16.5 months. Five patients improved following surgery, and one patient who had no deficits remained unchanged. Conclusions: Optimal surgical therapy in patients with calcified thoracic disc disease with compression of dural sac and myelopathy was resectioned via a transthoracic transpleural approach. The use of iCT-based registration and microscope-based AR significantly improved orientation in the operative field and facilitated safe resection of these lesions.

[Comparative analysis of the results of microdiscectomy and minimally invasive transforaminal lumbar interbody fusion in the treatment of adjacent-level intervertebral disc herniations with lumbosacral transitional vertebra in elderly patients.]

The purpose of the study was a comparative analysis the effectiveness of microsurgical discectomy and minimally invasive transforaminal lumbar interbody fusion in the treatment of disk herniation adjacent to the anomaly of the lumbosacral junction segment in elderly patients. The study included 80 elderly patients (over 60 years old), divided into two groups: the 1st-(n=39) who underwent microsurgical discectomy; the 2nd- patients (n=41) operated on using minimally invasive transforaminal interbody fusion and percutaneous transpedicular stabilization (MI-TLIF). For the comparative analysis, we used gender characteristics (gender, age), constitutional characteristics (BMI), degree of physical status according to ASA, intraoperative parameters of interventions and the specificity of postoperative patient management, clinical data, and the presence of complications. Long-term outcomes were assessed at a minimum follow-up of 3 years. As a result, it was found that the use of MI-TLIF allows achieving better long-term clinical outcomes, fewer major complications in comparison with the microsurgical discectomy technique in the treatment of disc herniation adjacent to the anomaly of the lumbosacral junction segment in elderly patients.

The safety of perioperative antiplatelet continuation without selection biases in microsurgical decompression surgery for single level lumbar spinal stenosis and lumbar disc herniotomy.

PURPOSE: Each institution or physician has to decide on an individual basis whether to continue or discontinue antiplatelet (AP) therapy before spinal surgery. The purpose of this study was to determine if perioperative AP continuation is safe during single-level microsurgical decompression (MSD) for treating lumbar spinal stenosis (LSS) and lumbar disc hernia (LDH) without selection bias. METHODS: Patients who underwent single-level MSD for LSS and LDH between April 2018 to December 2022 at our institute were included in this retrospective study. We collected data regarding baseline characteristics, medical history/comorbidities, epidural hematoma (EDH) volume, reoperation for EDH, differences between preoperative and one-day postoperative blood cell counts (ΔRBC), hemoglobin (ΔHGB), and hematocrits (ΔHCT), and perioperative thromboembolic complications. Patients were divided into two groups: the AP continuation group received AP treatment before surgery and the control group did not receive antiplatelet medication before surgery. Propensity scores for receiving AP agents were calculated, with one-to-one matching of estimated propensity scores to adjust for patient baseline characteristics and past histories. Reoperation for EDH, EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complications were compared between the groups. RESULTS: The 303 enrolled patients included 41 patients in the AP continuation group. After propensity score matching, the rate of reoperation for EDH, the EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complication rates were not significantly different between the groups. CONCLUSION: Perioperative AP continuation is safe for single-level lumbar MSD, even without biases.

Does obesity and varying body mass index affect the clinical outcomes and safety of biportal endoscopic lumbar decompression? A comparative cohort study.

BACKGROUND: Endoscopic spine surgery has recently grown in popularity due to the potential benefits of reduced pain and faster recovery time as compared to open surgery. Biportal spinal endoscopy has been successfully applied to lumbar disc herniations and lumbar spinal stenosis. Obesity is associated with increased risk of complications in spine surgery. Few prior studies have investigated the impact of obesity and associated medical comorbidities with biportal spinal endoscopy. METHODS: This study was a prospectively collected, retrospectively analyzed comparative cohort design. Patients were divided into cohorts of normal body weight (Bone Mass Index (BMI)18.0-24.9), overweight (BMI 25.0-29.9) and obese (BMI > 30.0) as defined by the World Health Organization (WHO). Patients underwent biportal spinal endoscopy by a single surgeon at a single institution for treatment of lumbar disc herniations and lumbar spinal stenosis. Demographic data, surgical complications, and patient-reported outcomes were analyzed. Statistics were calculated amongst treatment groups using analysis of variance and chi square where appropriate. Statistical significance was determined as p < 0.05. RESULTS: Eighty-four patients were followed. 26 (30.1%) were normal BMI, 35 (41.7%) were overweight and 23 (27.4%) were obese. Patients with increasing BMI had correspondingly greater American Society of Anesthesiologist (ASA) scores. There were no significant differences in VAS Back, VAS Leg, and ODI scores, or postoperative complications among the cohorts. There were no cases of surgical site infections in the cohort. All cohorts demonstrated significant improvement up to 1 year postoperatively. CONCLUSIONS: This study demonstrates that obesity is not a risk factor for increased perioperative complications with biportal spinal endoscopy and has similar clinical outcomes and safety profile as compared to patients with normal BMI. Biportal spinal endoscopy is a promising alternative to traditional techniques to treat common lumbar pathology.

A new technique for low back pain in lumbar disc herniation: percutaneous endoscopic lumbar discectomy combined with sinuvertebral nerve ablation.

BACKGROUND: Percutaneous endoscopic lumbar discectomy (PELD) has demonstrated efficacy in alleviating leg pain among patients with lumbar disc herniation. Nonetheless, residual back pain persists as a troubling issue for surgeons following the procedure. In the treatment of discogenic back pain, sinuvertebral nerve radiofrequency ablation has shown promising results. Nevertheless, the potential benefit of simultaneously implementing sinuvertebral nerve radiofrequency ablation during PELD surgery to address residual back pain has not been thoroughly investigated in current literature. METHODS: This retrospective study reviewed Lumbar disc herniation (LDH) patients with low back pain who underwent combined PELD and sinuvertebral nerve ablation in our department between January 2021 and September 2023. Residual low back pain post-surgery was assessed and compared with existing literature. RESULTS: A total of 80 patients, including 53 males and 27 females, were included in the study. Following surgical intervention, patients demonstrated remarkable improvements in pain and functional parameters. One month post-operatively, the VAS score for low back pain exhibited a 75% reduction (6.45 ± 1.3 to 1.61 ± 1.67), while the VAS score for leg pain decreased by 85% (7.89 ± 1.15 to 1.18 ± 1.26). Notably, the JOA score increased from 12.89 ± 5.48 to 25.35 ± 4.96, and the ODI score decreased form 59.48 ± 9.58 to 20.3 ± 5.37. These improvements were sustained at three months post-operatively. According to the modified Mac Nab criteria, the excellent and good rate was 88.75%. Residual low back pain is observed to be comparatively reduced compared to the findings documented in earlier literature. CONCLUSION: The combination of percutaneous endoscopic lumbar discectomy and sinuvertebral nerve ablation demonstrates effective improvement in low back pain for LDH patients.

The Value of 3D SPACE MRI in Differentiating between Sequestrated Lumbar Disc Herniation and Tumors: Two Cases and Literature.

Background: Intervertebral disc herniation, defined as the protrusion or extrusion of the disc mass outside the disc space, is common and easy to diagnose on conventional Magnetic Resonance imaging (MRI) or Computed Tomography (CT) scans. However, the sequestrated disc fragments are challenging to detect, and intervertebral disc mass displacement into the dural sac, which can lead to serious neurological problems such as Cauda equina syndrome (CES). The sequestrated disc fragments do not have specific clinical or radiological characteristics that can differentiate an atypical disc mass from a tumor, making the diagnosis difficult preoperatively. Herein, we describe the use of Sampling Perfection with Application Optimized Contrast using different flip angle Evolution in Magnetic Resonance Imaging (3D SPACE MRI) in the diagnosis of the intervertebral disc fragment that mimicked a tumor. Case presentation: In this study, we report two cases of sequestered lumbar disc herniation. The first case was a 37-year-old patient with a 2-year history of intermittent left lower limb pain that aggravates with exercise and is relieved at rest, while the second case was a 42-year-old patient with a history of 40 days of numbness and pain in the left lower limb. Conclusion: 3D SPACE MRI is a beneficial diagnostic imaging tool for discriminating between disc mass that mimics a tumor and a tumor before surgery. If the disc fragment mimicking a tumor can be identified before the operation, open surgical treatment won't be necessary for all patients.

Clinical Outcomes of Percutaneous Endoscopic Transforaminal Discectomy for the Treatment of Disc Herniation: A 3-Year Retrospective Study.

AIM: Percutaneous endoscopic transforaminal discectomy (PELD) is a new minimally invasive spine surgery for patients with lumbar disc herniation (LDH). Based on the 3-year follow-up data, the effect of PELD on the clinical outcomes of patients with LDH through a retrospective cohort study was analyzed in this article, so as to provide guidance for clinical selection of surgical options. METHODS: The clinical data of 150 patients with LDH admitted to our hospital from January 2019 to October 2020 were retrospectively analyzed. According to the surgical methods recorded in the medical record system, the patients were divided into the open lumbar microdiscectomy (OLM) group (n = 50) and the PELD group (n = 100). The surgical and postoperative recovery indicators of the two groups were compared after matching. These included incision length, intraoperative blood loss, operation time, postoperative ambulation time and hospital stays, recovery rate, short-term complication rate, Lumbar visual analogue scale (VAS) score, and Oswestry Disability Index (ODI) score. RESULTS: Compared with the OLM group, the PELD group had shorter incision length, shorter operation time, shorter postoperative ambulation time, shorter hospital stays, less intraoperative blood loss, lower short-term complication rate, lower lumbar pain and dysfunction scores at 3 months, 6 months, and 1 year after operation, higher short-term excellent-and-good recovery rate, and higher quality-of-life scores at 3 years after operation (p < 0.05). CONCLUSIONS: Compared with OLM, PELD in the treatment of LDH patients can reduce the operation time, blood loss, and length of hospital stays, suggesting a short-term postoperative recovery effect. Compared with OLM, PELD can also reduce the incidence of short-term complications, enhance the effect of pain control and improvement of dysfunction in the medium term, and improve the long-term quality of life.

Cauda Equina Syndrome: Cost Burden After Spinal Decompression.

STUDY DESIGN: Observational cohort study. OBJECTIVE: Cauda equina syndrome (CES) is a rare neurologic condition with potentially devastating consequences. The objective of this study was to compare the 2-year postoperative cost-associated treatments after posterior spinal decompression between patients with and without CES. METHODS: By analyzing a commercial insurance claims database, patients who underwent posterior spinal decompression with a concurrent diagnosis of lumbar spinal stenosis, radiculopathy, or disk herniation in 2017 were identified and included in the study. The primary outcome was the cost of payments for identified treatments in the 2-year period after surgery. Treatments included were (1) physical therapy (PT), (2) pain medication, (3) injections, (4) bladder management, (5) bowel management, (6) sexual dysfunction treatment, and (7) psychological treatment. RESULTS: In total, 3,140 patients (age, 55.3 ± 12.0 years; male, 62.2%) were included in the study. The average total cost of treatments identified was $2,996 ± 6,368 per patient. The overall cost of identified procedures was $2,969 ± 6,356 in non-CES patients, compared with $4,535 ± 6,898 in patients with CES ( P = 0.079). Among identified treatments, only PT and bladder management costs were significantly higher for patients with CES (PT: +115%, P < 0.001; bladder management: +697%, P < 0.001). The difference in overall cost was significant between patients (non-CES: $1,824 ± 3,667; CES: $3,022 ± 4,679; P = 0.020) in the first year. No difference was found in the second year. DISCUSSION: A short-term difference was observed in costs occurring in the first postoperative year. Cost of treatments was similar between patients apart from PT and bladder management.

Percutaneous endoscopic transforaminal discectomy and unilateral biportal endoscopic discectomy for lumbar disc herniation: a comparative analysis of learning curves.

OBJECTIVE: The purpose of this study was to investigate the learning curve of percutaneous endoscopic transforaminal discectomy (PETD) and interlaminar unilateral biportal endoscopic discectomy (UBED) in the treatment of lumbar disc herniation (LDH). METHODS: Between 2018 and 2023, 120 consecutive patients with lumbar disc herniation (LDH) treated by endoscopic lumbar discectomy were retrospectively included. The PETD group comprised 87 cases, and the UBED group comprised 33 cases. Cumulative sum analysis was used to evaluate the learning curve, with the occurrence of complications or unresolved symptoms defined as surgical failure, and variables of different phases of the learning curve being compared. RESULTS: The learning curve analysis identified the cutoff point at 40 cases in the PETD group and 15 cases in the UBED group. In the mastery phase, both PETD and UBED demonstrated a significant reduction in operation times (approximately 38 min for PTED and 49 min for UBED). In both PETD and UBED groups, the surgical failure rates during the learning and mastery phases showed no statistically significant differences. The visual analogue scale at the last follow-up was significantly lower than before surgery in both the PETD and UBED groups. CONCLUSION: PETD and UBED surgery are effective in the treatment of LDH with a low incidence of complications. However, achieving mastery in PETD necessitates a learning curve of 40 cases, while UBED requires a minimum of 15 cases to reach proficiency.

Extraforaminal Microdiscectomy for Upper Lumbar Disc Herniations: A Minimally Invasive Alternative Surgical Approach.

BACKGROUND: Various methods and techniques have been developed for extraforaminal decompression, particularly for far lateral lumbar disc herniation. Distinct anatomical differences are noticeable in the upper levels of the lumbar spine, which may complicate the related surgical approach. This study aimed to determine the safety and efficiency of the far lateral extraforaminal approach for the upper lumbar disc. METHODS: L1-2 and L2-3 migrated lumbar disc herniations were defined as upper lumbar disc herniations. 31 consecutive patients with upper lumbar disk herniation who underwent extraforaminal lumbar microdiscectomy between January 2018 and March 2022 were retrospectively investigated. The patients were assessed using the interval history, follow-up lower back and leg pain visual analog scale scores (0-100 mm), the Oswestry Disability Index (%), and modified MacNab criteria. RESULTS: 31 consecutive patients with upper lumbar disk herniation (20 men and 11 women) with a mean age of 52.8 ± 10.8 years (range 31-70 years) underwent extraforaminal lumbar microdiscectomy. The preoperative and postoperative visual analog scale scores and Oswestry Disability Index were significantly different (P < 0.001). According to the modified MacNab criteria, 23 patients showed excellent improvement, 5 showed good improvement, and 3 showed fair improvement; thus, the rate of satisfactory improvement was 90.3% at the 2-year follow-up. No patients required reoperation at the operative level during follow-up. CONCLUSIONS: Extraforaminal lumbar microdiscectomy is a safe and effective minimally invasive surgical technique for treating upper lumbar disc herniation.

Immediate Effects, Detailed Clinical Outcomes, and Prognostic Factors of Chemonucleolysis Using Condoliase for Lumbar Disc Herniation.

Chemonucleolysis utilizing condoliase is a minimally invasive treatment for lumbar disc herniation (LDH) aimed at reducing intervertebral disc pressure and enhancing symptoms. In this study, lower limb pain was measured using the numeric rating scale (NRS) the day after treatment and 1 and 3 months after treatment. Prognostic factors were assessed, categorizing participants into an improvement group (I-group) for NRS lower limb pain scores of ≥3.5 and a non-improvement group (N-group) for scores of <3.5. This study included a total of 225 patients treated between April 2020 and March 2023. The mean age was 46.5 ± 16.5 years, with 151 males. The mean duration of illness was 6.2 ± 8.52 months. As of the day after treatment, 60 cases were classified into the I-group, 118 cases at 1 month after surgery, and 152 cases at 3 months after surgery. The disease duration before treatment was significantly shorter in the I-group at 1 (8.19 ± 8.74 [I-group] vs. 5.17 ± 8.04 [N-group] months) and 3 months (8.51 [I-group] ± 7.35 vs. 5.69 ± 8.87[N-group] months) after treatment. The comparison of baseline leg pain NRS shows a difference in leg pain NRS in the I-group when compared on the day after treatment (6.02 ± 2.64 [I-group] vs. 7.50 ± 1.79 [N-group]), 1 (5.13 ± 2.69 [I-group] vs. 7.58 ± 1.66 [N-group]), and 3 months (4.42 ± 2.70 [I-group] vs. 7.34 ± 1.77 [N-group]). Chemonucleolysis using condoliase for LDH can improve symptoms the day after treatment and can be a minimally invasive treatment to avoid surgery.

Pseudomeningocele Mimicking Sciatica.

We report on an elderly woman with sciatica due to disc herniation, experiencing complete pain resolution following surgery. Four weeks later, she developed refractory, excruciating pain with foot palsy, prompting a lumbar magnetic resonance imaging that revealed no recurrent disc herniation. Upon exploration, intermittent nerve entrapment through the dural tear and pseudomeningocele was identified. Following dural repair and nerve repositioning, the postoperative course and long-term outcome were uneventful.In contrast to recurrent disc herniation, sciatica resulting from nerve entrapment by a pseudomeningocele is exceedingly rare. Its differential diagnosis is crucial in cases with seemingly unspectacular magnetic resonance imaging findings, as paralysis can occur in symptomatic patients. The radiological presence of a postoperative pseudomeningocele could be overlooked, and the cause of sciatica might become apparent solely during surgical exploration.