Influence of incidental dural tears and their primary microendoscopic repairs on surgical outcomes in patients undergoing microendoscopic lumbar surgery

Case Report: Bacterial meningitis due to cerebrospinal fluid leakage following unilateral biportal endoscopic spinal surgery: a cautionary tale

Unilateral biportal endoscopic spinal surgery (UBE) is a rapidly growing surgical method and has attracted much interest recently. The most common complication of this technique is cerebrospinal fluid (CSF) leakage due to intraoperative dural tears. There have been no reports of bacterial meningitis due to dural tears in UBE surgery and its treatment and prevention. We reported a 47 year-old man with CSF due to an intraoperative dural tear. A drainage tube was routinely placed and removed on the fourth day after surgery, resulting in fever and headache on the fifith postoperative day. Blood and CSF cultures showed Klebsiella pneumoniae infection, and with lumbar drainage and appropriate antibiotics based on sensitivity tests, the patient's fever and headache were effectively relieved. This case report suggests the importance of prolonged drainage tube placement, adequate drainage, careful intraoperative separation to avoid dural tears, and effective sensitive antibiotic therapy.

Incidental dural tears do not affect the overall patients' reported outcome of spine surgery at long-term follow-up: results of a systematic review

To conduct a systematic review of the literature in order to establish if there is an overall adverse effect of accidental durotomy on the long-term patients' reported outcome after elective spine surgery. A systematic literature search was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data about pre- and postoperative clinical outcomes of patients with accidental durotomy and patients without were extracted and analysed. After screening, eleven studies were included with a total of 80,541 patients. About 4112 of these patients (5.10%) had incidental dural tear. When comparing patients with dural tear to patients without, 9/11 authors found no patients' reported differences at last follow-up. One author found a slightly worse VAS back pain in dural tear patients, and another author found inferior SF-36 and ODI scores in dural tear patients (both below minimal clinically important difference). Accidental dural tear did not have a significant adverse effect on clinical outcome of elective spine surgery. More studies are needed to better demonstrate this result.

Incidence and management of dural tears in full-endoscopic unilateral laminotomies for bilateral lumbar decompression

PURPOSE

To report incidence of dural lacerations in lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) and to describe patient outcomes following a novel full-endoscopic bimanual durotomy repair.

METHODS

Retrospective review of prospectively collected database including 5.5 years of single surgeon experience with LE-ULBD. Patients with no durotomy were compared with patients who experienced intraoperative durotomy, including demographics, ASA score, prior surgery, number of levels treated, procedure time, hospital length of stay (LOS), visual analogue scale, perioperative complications, revision surgeries, use of analgesics, and Oswestry Disability Index (ODI).

RESULTS

In total, 13/174 patients (7.5%) undergoing LE-ULBD experienced intraoperative durotomy. No significant differences in demographic, clinical or operative variables were identified between the 2 groups. Sustaining a durotomy increased LOS (p = 0.0019); no differences in perioperative complications or rate of revision surgery were identified. There was no difference in minimally clinically important difference for ODI between groups (65.6% for no durotomy versus 55.6% for durotomy, p = 0.54).

CONCLUSION

In this cohort, sustaining a durotomy increased LOS but, with accompanying intraoperative repair, did not significantly affect rate of complications, revision surgery or functional outcomes. Our method of bimanual endoscopic dural repair provides an effective approach for repair of dural lacerations in interlaminar ULBD cases.

Complications of Unilateral Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis: A Meta-Analysis and Systematic Review

BACKGROUND

In recent years, unilateral biportal endoscopic spinal surgery has been used for the treatment of lumbar spinal stenosis with good results. Some investigators counted the total incidence of complications in unilateral biportal endoscopic surgery for lumbar spinal stenosis, but none have analyzed the incidence of specific complications. The present study further counted the incidence of specific complications and gave the possible causes of the complications.

METHODS

English databases including PubMed were searched to collect relevant literature on unilateral biportal endoscopic spinal surgery for lumbar spinal stenosis. The inquiry period is from January 1, 2015, to July 1, 2022. The literature was screened, information extracted, and risk of bias evaluated by the researchers, followed by Meta analysis using R4.2.1 and RStudio statistical software.

RESULTS

In total, we included 14 studies involving 707 patients. The included studies were retrospective case series, The results of the single-arm rate meta-analysis showed that the total complication rate of unilateral biportal endoscopic surgery treatment of lumbar spinal stenosis was 8.1% (95% confidence interval [CI] [0.060; 0.103]); of which, the highest incidence of dural tear was 4.5% (95% CI [0.030; 0.064]), the incidence of symptomatic postoperative spinal epidural hematoma was approximately 1.1% (95% CI [0.001; 0.027]), the incidence of incomplete decompression was 2.0% (95% CI [0.007; 0.038]), the incidence of transient palsy was 2.6% (95% CI [0.005; 0.057]).

CONCLUSIONS

The incidence of total complications of unilateral biportal endoscopic surgery for lumbar spinal stenosis was 8.1%, dural tear remained a major complication with an incidence of 4.5%, incomplete decompression was 2.0%, transient palsy was 2.6%, and, unexpectedly, symptomatic postoperative spinal epidural hematoma was only 1.1%.

Delta large-channel technique versus microscopy-assisted laminar fenestration decompression for lumbar spinal stenosis: a one-year prospective cohort study

PURPOSE

When it comes to treating lumbar spinal stenosis (LSS), a procedure known as microscope-assisted fenestration decompression has expediently become the gold standard. With the advancement of spinal endoscopy, the Delta large-channel approach has shown promising clinical outcomes in the management of lumbar spinal stenosis. However, case studies of this method being used to treat lumbar spinal stenosis are still uncommon. The purpose of this research was to examine how well microscopy-assisted laminectomy and the Delta large-channel approach work in treating LSS in the clinic.

METHODS

From May 2018 to June 2020, 149 patients diagnosed with LSS were divided into 80 patients in Delta large-channel technique groups (FE group) and 69 patients in microscope groups (Micro group). Lower back and lower limb pain were measured using the visual analogue scale (VAS-LBP and VAS-LP), while lower limb numbness was evaluated using the 11-point numerical rating scale (NRS-LN); modified Oswestry Disability Index (ODI) was used to evaluate the quality of life, and modified MacNab criteria were used to assess the clinical efficacy before surgery and at one week, three months, six months, and 12 months after surgery. All patients had single-level lumbar spinal stenosis, and clinical data such as hospital stay, operation time, intraoperative blood loss were statistically analyzed.

RESULTS

Finally, 111 patients (62 in FE group and 49 in Micro group) completed follow-up. Compared with preoperative results, postoperative VAS-LBP, VAS-LP, NRS-LN score and modified ODI score were significantly improved in 2 groups (P < 0.05), but there was no significant difference in postoperative follow-up at each time point (P > 0.05), Except 1 week after surgery, VAS-LBP in FE group was lower than that in Micro group (P < 0.05). It is noteworthy that the FE group had a shorter hospital stay, less intraoperative blood loss, and a quicker time of getting out of bed when compared with the microscope group，but the operation time was just the opposite (P < 0.05). The excellent and good rate was 83.87% in FE group and 85.71% in Micro group (P > 0.05).

CONCLUSIONS

Both microscope-assisted laminar fenestration decompression and Delta large-channel procedures provide satisfactory treatment outcomes, however the Delta large-channel approach has some potential advantages for the treatment of LSS, including quicker recovery and sooner reduced VAS-LBP. Long-term consequences, however, will necessitate additional follow-up and research.

Reoperation Rates of Microendoscopic Discectomy Compared With Conventional Open Lumbar Discectomy: A Large-database Study

BACKGROUND

Microendoscopic discectomy for lumbar disc herniation has been shown to be as effective as traditional microdiscectomy or open discectomy in terms of clinical outcomes such as pain relief, and it is less invasive. Nevertheless, the reoperation rate for microendoscopic discectomy compared with microdiscectomy or open discectomy remains unclear, possibly due to difficulties in conducting follow-up of sufficient duration and in obtaining information about reoperation in other facilities.

QUESTIONS/PURPOSES

(1) What is the rate of reoperation after microendoscopic discectomy for primary lumbar disc herniation on a large scale at a median of 4 years postoperatively? (2) Is there any difference in revision rate at a median of 4 years and within 90 days postoperatively based on surgical method?

METHODS

We conducted a retrospective, comparative study of adult patients who underwent microendoscopic discectomy or microdiscectomy or open discectomy for lumbar disc herniation from April 2008 to October 2017 and who were followed until October 2020 using a commercially available administrative claims database from JMDC Inc. This claims-based database provided information on individual patients collected across multiple hospitals, which improved the accuracy of postoperative reoperation rates. We included 3961 patients who received microendoscopic discectomy or microdiscectomy or open discectomy between April 2008 and October 2017 in the JMDC claims database. After applying exclusion criteria, 50% (1968 of 3961) of patients were eligible for this study. Propensity score-weighted analyses were conducted in 646 patients in the microendoscopic discectomy group and in 1322 in the microdiscectomy or open discectomy group, with a median (IQR) of 4 years (3 to 6) of follow-up in both groups. Mean patient age was 42 ± 12 years in the microendoscopic discectomy group and 43 ± 12 years in the microdiscectomy or open discectomy group. Males accounted for 78% (505 of 646) of patients in the microendoscopic discectomy group and 79% (1050 of 1322) of patients in microdiscectomy or open discectomy group. The proportion of patients with diabetes mellitus in the microendoscopic discectomy group (10% [64 of 646]) was less than in the microdiscectomy or open discectomy group (15% [195 of 1322]). The primary outcome was Kaplan-Meier survivorship free from any type of additional lumbar spine surgery at a median of 4 years after the index surgery. The secondary outcome was survival probability using the Kaplan-Meier method with endpoints of any type of reoperation within 90 days after the index surgery. To determine which procedure had the higher revision rate, we conducted propensity score overlap weighting analysis, which controlled for potential confounding variables such as age, sex, comorbidities, and type of hospital as well as Cox proportional hazard models to estimate HRs and 95% confidence intervals (CIs).

RESULTS

The 5-year cumulative reoperation rate was 12% (95% CI 9% to 15%) in the microendoscopic discectomy group and 7% (95% CI 6% to 9%) in the microdiscectomy or open discectomy group. After controlling for potentially confounding variables like age, sex, and diabetes mellitus, the microendoscopic discectomy group had a higher reoperation risk than the microdiscectomy or open discectomy group (weighted HR 1.57 [95% CI 1.14 to 2.16]; p = 0.004). Within 90 days of the index surgery, after controlling for potentially confounding variables like age, sex, and diabetes mellitus, we found no difference between the microendoscopic discectomy group and microdiscectomy or open discectomy group in terms of risk of reoperation (weighted HR 1.38 [95% CI 0.68 to 2.79]; p = 0.38).

CONCLUSION

Given the higher reoperation risk with microendoscopic discectomy compared with microdiscectomy or open discectomy at a median of 4 years of follow-up, surgeons should select microdiscectomy or open discectomy, despite the current popularity of microendoscopic discectomy. The revision risk of microendoscopic discectomy compared with microdiscectomy or open discectomy in the long term remains unclear. Future large, prospective, multicenter cohort studies with long-term follow-up are needed to confirm the association between microendoscopic discectomy and risk of reoperation.

LEVEL OF EVIDENCE

Level Ⅲ, therapeutic study.

Percutaneous fully endoscopic surgical management of the ruptured epidural catheter: Rescue of the novice anesthesiologist from his dilemma

BACKGROUND

Epidural nerve block and analgesia are basic anesthetic techniques for anesthesia. Epidural catheter rupture and partial retention are adverse events and rare complications of epidural catheterization technique. The probability of occurrence when applied by novice doctors is high. Removal of the residual catheter by conventional surgery causes more trauma and bleeding, slows recovery, and may causes medical disputes. We hypothesized that percutaneous spinal endoscopy a safe and effective remediation technique. This study was to analyze the efficacy and safety of removing the residual dural catheter by a percutaneous full-endoscopic technique(PFET) and discuss the clinical technique and precautions.

METHODS

This was a retrospective analysis of 7 patients with ruptured epidural catheters treated in our department from October 2015 to October 2019 using the PFET to remove the remaining epidural catheter. The operation time, intraoperative bleeding volume, surgical complications, and neurological symptoms before and after surgery were recorded. The Self-Rating Anxiety Scale (SAS) was used to assess the anxiety level of the anesthesiologist and the patient before and after the catheter removal operation, and the postoperative low back pain VAS score was recorded.

RESULTS

The remaining epidural catheter was successfully removed from all 7 patients. The operation time was 54.14 ± 14.45 (32-78) minutes, and the intraoperative blood loss was 9.134 ± 3.078 (5-15) ml. There were no cases of dural damage, cerebrospinal fluid leakage, sensorimotor dysfunction of the lower limbs, or bowel dysfunction. The anxiety symptoms of the patient and the anesthesiologist disappeared after removal of the residual epidural catheter. The patients' postoperative back pain VAS score was 0 to 2 points.

CONCLUSION

PFET is a safe and effective minimally invasive technique for removing residual epidural catheters. It causes less trauma and less bleeding, allows a faster recovery. It does not affect the recovery of patients from other surgical operations and reduces both medical risks and medical costs. At the same time, it avoids or reduces the occurrence of medical disputes and eliminates the pressure on novice anesthesiologists regarding similar adverse events.

Microendoscopic Lumbar Posterior Decompression Surgery for Lumbar Spinal Stenosis: Literature Review

Lumbar spinal stenosis (LSS) is a common disease in the elderly, mostly due to degenerative changes in the lumbar spinal complex. Decompression surgery is the standard surgical treatment for LSS. Classically, total laminectomy—which involves resection of the spinous process, entire laminae and medial facet—has been the standard decompression technique; however, it can cause post-surgical instability. To overcome this disadvantage, various minimally invasive techniques that preserve the stabilization structures of the spine have been developed, and surgeons have begun to re-evaluate decompression surgery from the standpoint of reduced invasiveness and cost. More than two decades have passed since the introduction of microendoscopic spine surgery, and studies continue to shed light on its advantages and limitations as new knowledge becomes available. This article is a narrative review of the available literature, along with authors’ experience, regarding the indications, surgical techniques, clinical outcomes, and limitations/complications of microendoscopic decompression for LSS.

Comparison between microendoscopic laminectomy and open posterior decompression surgery for single-level lumbar spinal stenosis: a multicenter retrospective cohort study

Background

Microendoscopic laminectomy (MEL), in which a 16-mm tubular retractor with an internal scope is used, has shown excellent surgical results for patients with lumbar spinal canal stenosis. However, no reports have directly compared MEL with open laminectomy. This study aimed to elucidate patient-reported outcomes (PROs) and perioperative complications in patients undergoing MEL versus open laminectomy.

Methods

This is a multicenter retrospective cohort study of prospectively registered patients who underwent lumbar spinal surgery at one of the six high-volume spine centers between April 2017 and September 2018. A total of 258 patients who underwent single posterior lumbar decompression at L4/L5 were enrolled in the study. With regard to demographic data, we prospectively used chart sheets to evaluate the diagnosis, operative procedure, operation time, estimated blood loss, and complications. The follow-up period was 1-year. PROs included a numerical rating scale (NRS) for lower back pain and leg pain, the Oswestry Disability Index (ODI), EuroQol 5 Dimension (EQ-5D), and patient satisfaction with the treatment.

Results

Of the 258 patients enrolled, 252 (97%) completed the 1-year follow-up. Of the 252, 130 underwent MEL (MEL group) and 122 underwent open decompression (open group). The MEL group required a significantly shorter operating time and sustained lesser intraoperative blood loss compared with the open group. The MEL group showed shorter length of postoperative hospitalization than the open group. The overall complication rate was similar (8.2% in the MEL group versus 7.7% in the open group), and the revision rate did not significantly differ. As for PROs, both preoperative and postoperative values did not significantly differ between the two groups. However, the satisfaction rate was higher in the MEL group (74%) than in the open group (53%) (p = 0.02).

Conclusions

MEL required a significantly shorter operating time and resulted in lesser intraoperative blood loss compared with laminectomy. Postoperative PROs and complication rates were not significantly different between the procedures, although MEL demonstrated a better satisfaction rate.

Outcomes and complications following minimally invasive excision of synovial cysts of the lumbar spine: A systematic review and meta-analysis

OBJECTIVE

Lumbar synovial cysts (LSC) are one of the manifestations of spinal degenerative cascade. Spinal stenosis or presence of instability in these patients can lead to various symptoms and surgery is indicated following failure of non-operative management for symptomatic synovial cysts. Surgery when performed consists of either decompression with resection of cyst with our without fusion. The efficacy and complications of minimally invasive techniques using tubular retractors (microscopic or endoscopic) in comparison to traditional open techniques remain to be studied.

METHODS

A comprehensive search of different databases was performed to retrieve studies describing the use of minimal invasive techniques using tubular retractors (both microscopic and endoscopic) in patients with LSC. Meta-analysis with subgroup analysis and metaregression was done.

RESULTS

Twenty articles were selected for the systematic review and meta-analysis with total of 388 patients. Eighty-six percent of patients (95% Confidence Interval (CI): 80-90%) had favorable outcome as per Macnab's criteria (excellent and good outcome) with the pooled standard mean difference between preoperative and postoperative Oswestry Disability Index (ODI) being -4.44 (95% CI -8.78 to -0.10, p-value=0.0474, I² 82%). The pooled percentage change in visual analogue scale (VAS) after surgery was 76.5% (95% CI 66.9-84%, I² 82%). The pooled proportion of incidental durotomies, cyst recurrence and patients requiring operation being 8% (95% CI 5-11%, I² 0%), 4% (95% CI 2-7%, I² 0%,) and 5% (95% CI 3-9%) respectively. Studies were homogeneous with an I² value of 0%. Subgroup analysis revealed no significant difference in the outcome rates or complication rates between the microscopic and endoscopic subgroups.

CONCLUSION

Minimally invasive techniques for the resection of LSC is a safe and effective alternative to traditional surgical approaches with no difference between the microscopic and endoscopic approaches.

Clinical Outcome of Spine Surgery Complicated by Accidental Dural Tears: Meta-Analysis of the Literature

STUDY DESIGN

Systemic review and meta-analysis.

OBJECTIVES

Several studies have reported the impact of accidental dural tears (DT) on the outcome of spinal surgery, some with conflicting results. Therefore, the aim of this study was to carry out a systemic review and meta-analysis of the literature to establish the overall clinical outcome of spinal surgery following accidental DT.

METHOD

A systemic literature search was carried out. Postoperative improvement in Oswestry Disability Index (ODI), Short-Form 36 survey (SF36), leg pain visual analogue scale (VAS), and back pain VAS were compared between patients with and without DT at different time intervals.

RESULTS

Eleven studies were included in this meta-analysis. There was a slightly better improvement in ODI and leg VAS score (standardized mean difference of -0.06, 95% confidence interval [CI] -0.12 to -0.01, and -0.06, 95% CI -0.09 to -0.02, respectively) in patients without DT at 12 months postsurgery, but this effect was not demonstrated at any other time intervals up to 4 years. There were no differences in the overall SF36 (function) score at any time interval or back pain VAS at 12 months.

CONCLUSION

Based on this study, accidental DT did not have an overall significant adverse impact on the short-term clinical outcome of spinal surgery. More studies are needed to address the long-term impact and other outcome measures including other immediate complications of DT.

Influence of unintended dural tears on postoperative outcomes in lumbar surgery patients: a multicenter observational study with propensity scoring

BACKGROUND CONTEXT

Unintended dural tears (DTs) are common in spinal surgeries. Some authors have reported that the outcomes in lumbar surgery patients with DTs are equivalent to those in patients without DTs, but this remains uncertain.

PURPOSE

To assess the effect of unintended DTs on postoperative patient-reported outcomes.

STUDY DESIGN/SETTING

A multicenter retrospective observational study.

PATIENT SAMPLE

We enrolled patients undergoing lumbar spine surgery at eight hospitals between April 2017 and November 2018.

OUTCOME MEASURES

We collected data regarding patients' backgrounds, operative factors, occurrence of unplanned DTs during surgery, postoperative complications, patient-reported outcomes, such as pain or dysesthesia of the lower back, buttock, leg, or plantar area, EuroQol 5 Dimension (EQ-5D), Oswestry Disability Index (ODI) scores, and postoperative satisfaction.

METHODS

We divided the patients into a DT- group (without DTs) and a DT+ group (with DTs). First, multivariate logistic regression analyses were conducted to reveal risk factors for occurrence of DTs. Then, we used propensity score matching to obtain a matched DT- group (mDT- group) and a matched DT+ (mDT+ group). Student's t test was used for comparing continuous variables and Pearson's chi-square test for comparing categorical variables between the two groups.

RESULTS

We enrolled 2,146 patients in this study. The number of patients with unintended DTs was 166 (7.7%). Older age, body mass index, ossification of posterior longitudinal ligament / yellow ligament, spinal deformity, and revision surgery were significant risk factors for DTs. We used propensity score matching to compare 163 of the patients with DTs with 163 patients without DTs. No significant difference was found in postoperative pain or dysesthesia of the lower back, buttock, leg, and plantar area between the mDT- and mDT+ groups. When comparing preoperative with postoperative pain and dysesthesia, a statistically significant improvement was found in each group (p<.01 for all variables) except for sensory disorder of the plantar area, where a significant improvement was only observed in dysesthesia of the mDT- group (p<.01). Although some improvements were observed, they were not statistically significant in terms of pain in the mDT- (p=.06) and mDT+ (p=.13) groups and dysesthesia in the mDT+ (p=.13) group. No significant differences were found in postoperative outcomes, such as EQ-5D (p=.44) and ODI (p=.89) scores, and postoperative satisfaction (p=.73) between the two groups.

CONCLUSIONS

Although insufficient improvement of sensory disorder of the plantar area was observed, patients with DTs showed almost equivalent postoperative outcomes compared with patients without DTs.

Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery

Study Design

Here we perform a retrospective analysis regarding an incidental dural tear (IDT) during biportal endoscopic spinal surgery (BESS).

Purpose

This study investigates the causes of IDT specifically related to technical procedures of BESS with the aim of lowering its risk during training.

Overview of Literature

The incidence of dural tear is reported 0.5%–18% in open spinal surgery and 1.7%–4.3% during endoscopic spinal surgery. Because conversion to open surgery for direct repair could become necessary during endoscopic spinal surgery, prevention of this complication is essential.

Methods

We have retrospectively studied IDTs by four surgeons during 1 or 2 years after starting BESS for lumbar degenerative diseases and analyzed the locations, sizes, and specific endoscopic conditions specific to each.

Results

Twenty-five cases (1.6%) of IDTs among 1,551 cases of BESS occurred; 13 cases (52%) of these were within the first 6 months. The locations were dorsal midline in 12 cases, ipsilateral side in 11 cases, and contralateral side in two cases. The tear sizes were <10 mm in 20 cases and ≥10 mm in five cases. IDT commonly occurred due to injury of central dural folding during flavectomy under turbid surgical fields due to small bleeds under water. Twenty cases with IDTs of <10 mm were treated well with the patch technique. Among five cases of ≥10 mm, three underwent open repair within a few days, and two of these which failed to conservative management required a delayed revision operation due to pseudomeningocele. No cases progressed to surgical site infection or infectious spondylitis.

Conclusions

IDTs of <10 mm can be successfully treated with the patch technique. To prevent IDT during the early learning period, maintaining clear visibility by securing fluent saline outflow and meticulous hemostasis of small bleeding from exposed cancellous bone and epidural vessels is essential with caution not to injure the central dural folding during midline flavectomy.

Incidence and Implications of Incidental Durotomy in Transforaminal Endoscopic Spine Surgery: Case Series

OBJECTIVE

To evaluate the incidence and outcomes of incidental durotomy in transforaminal endoscopic spine surgery.

METHODS

Transforaminal lumbar endoscopic procedures were performed by 2 surgeons in 907 patients over a period of 4 years from 2014 to 2018. Patient data were evaluated retrospectively in these patients with a minimum follow-up of 1 year.

RESULTS

In 907 patients over 4 years there were 5 durotomies: 4 incidental and 1 intentional. The rate for incidental durotomy was therefore 0.4%. There were no adverse outcomes from the incidental durotomies, and only 1 patient noted a headache.

CONCLUSIONS

Incidental durotomy is a rare complication of transforaminal lumbar endoscopic spine surgery and appears to occur more likely in patients who have undergone previous spine surgery at the site of the endoscopic procedure, not unexpectantly. Glues, patches, and bedrest were among the various methods used after durotomy. In this series there were no cases of symptomatic spinal fluid leakage or pseudomeningocele seen. Only 20% of patients who had durotomies noted a headache in the immediate postoperative period.