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.

Minimally invasive tubular microdiscectomy for recurrent lumbar disc herniation: step-by-step technical description with safe scar dissection

INTRODUCTION

Recurrent lumbar disc herniation (RLDH) is one of the most common reasons for re-operation after primary lumbar disc herniation with an incidence ranging from 5 to 23%. Numerous RLDH studies have been conducted; however, no available studies have provided a specific description of the use of the tubular retractor discectomy technique for RLDH emphasizing safe scar dissection. The objective of this study is to describe a detailed step-by-step technique for RLDH.

MATERIAL AND METHODS

A surgical technique reporting on our experience from the year 2013-2021 in 9 patients with RLDH at the same level and same side was included in the study. Clinical outcomes were assessed using the visual analog score (VAS) for leg pain before and three months after surgery.

RESULTS

A significant improvement was observed between the preoperative and postoperative VASs [mean (SD): 9.2 (1) vs. 1.5 (1)] for all patients. We did not report any incidental durotomy, neurological deficits or mortality in this study. One patient had superficial wound infection. The study is limited by small population, short follow-up and not reporting stability or spondylolisthesis.

CONCLUSION

A modified tubular discectomy technique with safe scar dissection is effective for RLDH treatment. Technically, the only scar needed to be dissected is the scar lateral to the exposed normal dura and the scar extended caudally till the level of the superior end plate of the targeted disc space where the scar can be entered ventrally and the disc fragment retrieved. Adherence to the step-by-step procedure described in our study will help surgeons operate with more confidence and minimize complications of recurrent lumbar disc herniation.

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.

Surgical management of an ossified giant lumbar pseudomeningocele: A case report

BACKGROUND

Pseudomeningoceles (PMs) are infrequent complications of spine surgery resulting from incidental durotomy and subsequent extravasation of cerebrospinal fluid. Giant PMs (GPMs), defined as ≥8 cm in major diameter, are rarely reported in the literature and present a challenge due to a lack of clear guidelines for surgical management.

CASE DESCRIPTION

Here, the authors discuss the successful surgical management of a 25.3 cm lumbar GPM that became calcified 3 years following an initial T10-S2 laminectomy with instrumented fusion performed at an outside-hospital.

CONCLUSION

This report focuses on the successful 3-year delayed surgical intervention for the management of an ossified GPM.

Intradural lumbar disc herniation: A case report and literature review

Study design and objection

Intradural disc herniation is a unusual disease associated with spinal surgery. The definitive diagnosis of intradural herniation depends on intraoperative findings.

Summary of background data

We present the case of a 63-year-old woman with backache and left sciatica radiation for more than two months. The L2/3 laminectomy and discectomy were performed after magnetic resonance imaging (MRI) study; however, no disc rupture was noted during surgery. Follow-up lumbar spine MRI revealed one large, ruptured disc. The patient underwent revision surgery with durotomy. The large intradural disc was found and removed piece by piece.

Methods Results and Conclusions

Intradural disc herniation, especially large herniation, is hard to diagnose specifically despite the progression of neuroradiologic imaging techniques. A durotomy procedure should be considered if there is a missing ruptured disc or a palpable intradural mass during surgery.

Risk Factors for Postoperative Cerebrospinal Fluid Leakage After Intradural Spine Surgery

OBJECTIVE

Well-defined risk factors for cerebrospinal fluid leakage (CSFL) after intradural spine surgery are scarce in the literature. The aim of the present study was to identify patient- and surgery-related risk factors and the incidence of CSFL.

METHODS

For the present retrospective cohort study, we identified consecutive patients who had undergone intradural spine surgery between 2009 and 2021 at our department. The primary endpoint was the incidence of clinically or radiologically proven CSFL. The effects of the clinical and surgical factors on the occurrence of CSFL were analyzed.

RESULTS

A total of 375 patients (60.3% women; mean age, 54 ± 16.5 years) were included. Of the 375 patients, 30 (8%) had experienced postoperative CSFL and, thus, a significantly greater risk of wound healing disorders (odds ratio [OR], 24.9; 95% confidence interval [CI], 9.3-66.7) and surgical site infections (OR, 8.4; 95% CI, 2.6-27.7; P < 0.01 for each). No patient-related factors were associated with the development of CSFL. Previous surgery at the index level correlated significantly with the occurrence of postoperative CSFL (OR, 2.76; 95% CI, 1.1-6.8; P = 0.03) on multivariate analysis. Furthermore, patients with intradural tumors tended to have a greater risk of CSFL (OR, 2.3; 95% CI, 0.9-5.8; P = 0.07). Surgery-related factors did not influence the occurrence of CSFL. Surgery on the thoracic spine had resulted in a significantly lower postoperative CSFL rate compared with surgery on the cervical or lumbar spine (OR, -2.5; 95% CI, 1.3-4.9; P = 0.02).

CONCLUSIONS

Our study found no modifiable risk factors for preventing CSFL after intradural spine surgery. Patients with previous surgery at the index level had a greater risk of CSFL. The occurrence of CSFL resulted in significantly more wound healing disorders and surgical site infections, necessitating further therapy.

Open epidural blood patch to augment durotomy repair in lumbar spine surgery: surgical technique and cohort study

BACKGROUND CONTEXT

Incidental durotomy during elective spine surgery is relatively common. While usually benign and self-limited, it can be associated with morbidity, increased cost, and medicolegal ramifications. Dural repair typically involves performing a primary closure using a suture or dural staple; repairs are then frequently augmented with a sealant, patch, or fat/fascial graft. Although primary repair of an incidental durotomy is standard practice, the ideal secondary sealant or augment choice remains unclear. A wide variety of commercially available dural sealant options exist, and while none have demonstrated consistent superiority, all are associated with single-use costs in the hundreds to thousands of dollars and have concerns regarding swelling, local inflammation, or short-lived dural adherence.

PURPOSE

The goal of this study is to compare the results of dural repair augmentation using an open intraoperative epidural blood patch to a hydrogel technique.

STUDY DESIGN/SETTING

Retrospective comparative cohort study at an academic referral center PATIENT SAMPLE: Adult patients undergoing lumbar spine surgery from March 2017 to January 2021 who sustained an incidental durotomy. Patients undergoing surgery for infection were excluded.

OUTCOME MEASURES

The primary outcome was failure of the repair as determined by a return to the operating room for re-exploration of a persistent cerebrospinal fluid (CSF) leak within 30 days of the index procedure. A secondary outcome was the incidence of a postoperative positional headache, and if present, the method used to obtain resolution. The primary predictor was use of a suture and hydrogel technique ("hydrogel" group), or the use of an epidural blood patch ("EBP" group).

METHODS

The method for applying an open epidural blood patch is presented in detail and involves primarily repairing the durotomy followed by allowing whole blood to pool and clot in the operative field until the durotomy is completely covered. This was compared with a group of patients undergoing secondary augmentation with commercially available hydrogel. In both groups, mechanical resistance to CSF leakage was confirmed with direct visualization and a Valsalva maneuver, respectively. Patients were instructed to remain flat until the morning after surgery. Chart review was used for data abstraction on preoperative, demographic, perioperative, and postoperative clinical factors. To compare between the hydrogel and EBP group, Wilcoxon rank-sum testing was used to test for non-parametric comparisons of means, and chi-square testing between binomial data.

RESULTS

Of 732 patients during the study period, forty-eight patients met study criteria. Twenty-five patients were in the hydrogel group and 23 in the EBP group. Mean age was 69.3 years (standard error 1.3 years). Patients were predominantly female (n = 31, 64.6%) with a mean BMI of 29.5 (SE 0.8), with no significant baseline differences between the hydrogel and EBP groups. Two patients in the hydrogel group (8.0%) and two in the EBP group (8.7%) had mild positional headaches postoperatively that resolved without intervention within 24 hours. One (4.3%) patient in the EBP group had positional headaches following an initial headache-free period; this patient was returned to the operating room and no evidence of a persistent CSF leak was found despite meticulous exploration.

CONCLUSIONS

An open, intraoperatively placed epidural blood patch may be an efficacious and cost-effective way to manage an incidental durotomy. This method merits further study as an allergy-free, no swell, cost-neutral method of dural repair augmentation.

Incidence of Dural Tears in Open versus Minimally Invasive Spine Surgery: A Single-Center Prospective Study

Study Design

A prospective comparative study.

Purpose

To compare the incidence of unintended durotomy and return to work after open surgery versus minimally invasive spine surgery (MIS) for degenerative lumbar pathologies.

Overview of Literature

The incidence of accidental durotomy varies between 0.3% and 35%. Most of these are from open surgeries, and only a handful of studies have involved the MIS approach. No single-center studies have compared open surgery with MIS, especially in the context of early return to work and dural tear (DT).

Methods

This study included 420 operated cases of degenerative lumbar pathology with a prospective follow-up of at least 6 months. Patients were divided into the open surgery and MIS groups, and the incidences of DT, early return to work, and various demographic and operative factors were compared.

Results

A total of 156 and 264 patients underwent MIS and open surgery, respectively. Incidental durotomy was documented in 52 cases (12.4%); this was significantly less in the MIS group versus the open surgery group (6.4% vs. 15.9%, p<0.05). In the open surgery group, four patients underwent revision for persistent dural leak or pseudomeningocele, but none of the cases in the MIS group had revision surgery due to DT-related complications. The incidence of DT was higher among patients with high body mass index, patients with diabetes mellitus, and patients who underwent revision surgery (p<0.05) regardless of the approach. The MIS group returned to work significantly earlier.

Conclusions

MIS was associated with a significantly lower incidence of DT and earlier return to work compared with open surgery among patients with degenerative lumbar pathology.

Incidental Durotomy Following Surgery for Degenerative Lumbar Disease and the Impact of Minimally Invasive Surgical Technique on the Rate and Need for Surgical Revision: A Case Series

BACKGROUND

Incidental durotomy (ID) is a common complication during lumbar spine surgery. A paucity of literature has studied the impact of minimally invasive surgery (MIS) on durotomy rates and strategies for repair as compared to open surgery.

OBJECTIVE

To examine the impact that MIS techniques have on the durotomy rate, repair techniques, and need for surgical revision following surgery for degenerative lumbar disease as compared to open technique.

METHODS

A single-center retrospective review of consecutive cases between 2013 and 2016 was performed. All patients underwent lumbar decompression with or without instrumented fusion for degenerative pathology using either open posterior or MIS techniques. ID rate, closure technique, and need for surgical revision related to the durotomy were recorded.

RESULTS

A total of 1,196 patients were included with an overall ID rate of 6.8%. There was no difference between open or minimally invasive surgical techniques (P = .14). There was a higher durotomy rate with open technique in patients that underwent decompression with fusion (P = .03) as well as in revision cases (P = .02). Primary repair was feasible more frequently in the open group (P = .001), whereas use of dural substitute (P < .001) was more common in the MIS group. Fibrin sealant was used routinely in both groups (P = .34). There were no failed repairs, regardless of technique used.

CONCLUSION

MIS techniques may reduce durotomies in cases involving instrumentation or revisions. Use of dural substitute onlay and fibrin sealant was effective at preventing reoperation. Both MIS and open techniques result in a low rate of future surgical revision when a durotomy occurs.

Dural Tear Does not Increase the Rate of Venous Thromboembolic Disease in Patients Undergoing Elective Lumbar Decompression with Instrumented Fusion

OBJECTIVE

Evaluate if dural tears (DTs) are an indirect risk factor for venous thromboembolic disease through increased recumbency in patients undergoing elective lumbar decompression and instrumented fusion.

METHODS

This was a retrospective cohort study of consecutive patients undergoing elective lumbar decompression and instrumented fusion at a single institution between 2016 and 2019. Patients were divided into cohorts: those who sustained a dural tear and those who did not. The cohorts were compared using Student's t-test or Wilcoxon Rank Sum for continuous variables and Fisher exact or chi-squared test for nominal variables.

RESULTS

Six-hundred and eleven patients met inclusion criteria, among which 144 patients (23.6%) sustained a DT. The DT cohort tended to be older (63.6 vs. 60.6 years, P = 0.0052) and have more comorbidities (Charlson Comorbidity Index 2.75 vs. 2.35, P = 0.0056). There was no significant difference in the rate of symptomatic deep vein thrombosis (2.1% vs. 2.6%, P = 1.0) or pulmonary embolus (1.4% vs. 1.50%, P = 1.0). Intraoperatively, DT was associated with increased blood loss (754 mL vs. 512 mL, P < 0.0001), operative time (224 vs. 195 minutes, P < 0.0001), and rate of transfusion (19.4% vs. 9.4%, P = 0.0018). Postoperatively, DT was associated with increased time to ambulation (2.6 vs. 1.4 days, P < 0.0001), length of stay (5.8 vs. 4.0 days, P < 0.0001), and rate of discharge to rehab (38.9 vs. 25.3%, P = 0.0021).

CONCLUSIONS

While DTs during elective lumbar decompression and instrumentation led to later ambulation and longer hospital stays, the increased recumbency did not significantly increase the rate of symptomatic venous thromboembolic disease.

Intradural disc herniation at the L1-2 level

Background

Intradural disc herniations (IDHs) are rare, are difficult to diagnose on preoperative MR/CT imaging, and typically, are most readily confirmed at the time of surgery. However, one of the greatest challenges posed by these lesions, is the repair of the ventral dural rent.

Case Description

A 55-year-old male with a 20-year history of lumbago presented with low back pain and right lower extremity sciatica of 3 months' duration. The MR and CT studies showed a compressive lesion at the L1-2 level. There was no original suspicion that this was an IDH. At surgery, performed under the operating microscope, a subtotal L1-L2 laminectomy was performed (i.e. while lysing severe adhesions between the posterior longitudinal ligament and the ventral dura, a traumatic durotomy occurred. White, spongious, friable, soft tissue, and free-floating disc fragments extruded through the durotomy site. Notably, it was initially considered to be a tumor rather than a disc. Once all fragments had been delivered, unsuccessful attempts were made to repair the ventral dura. Further efforts were curtailed due to concern that they would result in damage to multiple ventral nerve rootlets. Despite the lack of primary dural repair, the secondary measures resulted in no postoperative recurrent cerebrospinal fluid leakage (CSF) and a smooth postoperative surgical course.

Conclusion

IDH at the L1-2 level is rare, and preoperative MR/CT studies may not always document their intradural location. Ideally, ventral dural tears attributed to these lesions should be directly repaired and/or managed with additional adjunctive CSF leak repair techniques (i.e. muscle patch grafts, microfibrillar collagen, and fibrin sealants).

Two cases of supratentorial lobar intracranial hemorrhage following lumbar decompression and stabilization

Background

Lumbar spine surgery with or without intraoperative dural tear (DT) may contribute to postoperative subdural hematomas and/or cerebellar intracranial hemorrhages (ICHs). Here, we present two patients, one with and one without an intraoperative DT occurring during lumbar surgery, both of whom developed acute postoperative supratentorial ICHs.

Case Description

Two patients developed supratentorial lobar ICH following lumbar decompressions and fusion. The first patient, without an intraoperative DT, developed multiple ICHs involving the left cerebellum and left temporal lobe. The second patient, following an L4-5 decompression/instrumented fusion involving a DT, postoperatively developed a large right frontal ICH.

Conclusion

Here, two patients undergoing lumbar spine surgery with/without DT subsequently developed significant ICH.

Microsurgery for intradural epidermoid cyst at cauda equina level in a 9-year-old child: A case report

Introduction and importance

Epidermoid cysts are rare benign tumors. Here, we present a case of spontaneous intradural epidermoid cyst at cauda equina level in a 9-year-old patient, which we believed the first case to be reported in Vietnam.

Case presentation

A 9-year-old boy presented with 4 months of spontaneous left lower extremity muscle weakness and paresthesia. The MRI images suggested the diagnosis of intradural epidermoid cyst at cauda equina level. The patient underwent L5–S1 laminectomy and durotomy for tumor resection. The histology confirmed the diagnosis of epidermoid cyst. Post-operative images demonstrated total cyst removal.

Clinical discussion

The epidermiology, presentation and diagnosis and strategy of treatments as well as their outcomes were discussed.

Conclusion

Diagnosis of spinal epidermoid cyst is often delayed for its obscure presentation. Microsurgical dissection along with intra-operative mobile C-Arms enable total tumor resection while preserving spinal stability and neurological function. Follow-up with post-operative magnetic resonance imaging and tumor marker are helpful.

•

Diagnosis of spinal epidermoid cyst is often delayed for its obscure presentation.

•

Microsurgical dissection and mobile C-Arm enables total tumor resection while preserving stability and neurological function

•

Magnetic resonance imaging and tumor marker are helpful in follow-up.

Effectiveness of Repair Techniques for Spinal Dural Tears: A Systematic Review

BACKGROUND

Incidental or intentional durotomy in spine surgery is associated with a risk of cerebrospinal fluid (CSF) leakage and reoperation. Several strategies have been introduced, but the incomplete closure is still relatively frequent and troublesome. In this study, we review current evidence on spinal dural repair strategies and evaluate their efficacy.

METHODS

PubMed, Web of Science, and Scopus were used to search primary studies about the repair of the spinal dura with different techniques. Of 265 articles found, 11 studies, which specified repair techniques and postoperative outcomes, were included for qualitative and quantitative analysis. The primary outcomes were CSF leakage and postoperative infection.

RESULTS

The outcomes of different dural repair techniques were available in 776 cases. Pooled analysis of 11 studies demonstrated that the most commonly used technique was a combination of primary closure, patch or graft, and sealant (22.7%, 176/776). A combination of primary closure and patch or graft resulted in the lowest rate of CSF leakage (5.5%, 7/128). In this study, sealants as an adjunct to primary closure (13.7%, 18/131) did not significantly reduce the rate of CSF leakage compared with primary closure alone (17.6%, 18/102). The rates of infection and postoperative neurologic deficit were similar regardless of the repair techniques.

CONCLUSIONS

Although the use of sealants has become prevalent, available sealants as an adjunct to primary closure did not reduce the rate of CSF leakage compared with primary closure. The combination of primary closure and patches or grafts could be effective in decreasing postoperative CSF leakage.

Anatomy of the posterolateral spinal epidural ligaments

Background

The epidural ligaments (ELs) (of Hofmann) were described as fibrous bands interconnecting the ventrolateral spinal dura and the posterior longitudinal ligament below L1. They are hardly ever discussed in the literature or considered in hypothesis-driven basic science experiments or spine biomechanical models.

Methods

Intraoperative photographs were obtained to illustrate a group of posterolateral spinal ELs. In addition, electronic database searches (PubMed, Ovid Embase, and SCOPUS) were utilized to summarize the anatomy, and relevant clinical and surgical factors impacting these ELs.

Results

ELs attach circumferentially at most spinal levels. They anchor the nerve root sleeves ventrally, and therefore, may play a role in the some idiopathic neurologic deficits (e.g., postoperative radiculopathies, C5 palsies) in patients without radiological compression. The posterolateral ELs originate on the dura dorsal to the nerve root sleeves and insert on the ipsilateral lamina, interlaminar ligament, and facet capsule. They appear to be continuous with the peridural membrane, a fibrovascular sheath that surrounds the thecal sac and serves as a scaffold for the internal vertebral venous plexus of Batson and epidural fat.

Conclusion

The spinal ELs should be divided sharply during surgery to prevent durotomies, especially in patients with advanced spondylosis and facet arthropathy. Disconnecting these ligaments releases the thecal sac laterally and ventrally, allowing for medial mobilization when performing discectomies or for working in the ventral epidural space.

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.

Retrospective evaluation of surgical outcomes after closure of durotomy in eight dogs affected by spinal subarachnoid diverticulum

Background:

Canine spinal subarachnoid diverticulum has been studied since 1968 and a few advancements have been made with regard to the treatment of this disease. Several surgical techniques have been proposed which include durectomy, fenestration, and/or marsupilization with the latter two regarded as the more favorable surgical treatments.

Aim:

In this retrospective study, we evaluated the closure of the durotomy incision in the treatment of canine spinal subarachnoid diverticulum.

Methods:

We retrospectively evaluated eight dogs with clinical signs and magnetic resonance imaging findings consistent with spinal subarachnoid diverticulum located in the cervical and thoracolumbar area. This was to determine whether the fenestration with closure of durotomy was superior to the marsupialization technique. In all dogs, fenestration and removal of subarachnoid adherences alongside closure of the durotomy were carried out.

Results:

Mild post-operative deterioration was observed in all dogs. Follow-up from 7 to 36 months indicated a satisfactory outcome.

Conclusion:

We conclude that the closure of durotomy has similar short-term and long-term outcomes compared to the previous reported studies. These results suggest that the closure of durotomy is a viable technique for spinal subarachnoid diverticulum.

Risk factors for persistent numbness following decompression surgery for lumbar spinal stenosis

OBJECTIVE

Decompression surgery is a mainstay of surgical treatment for lumbar spinal stenosis (LSS). However, up to 30% of patients have low satisfaction due to residual symptoms. In the clinical setting, improvements in leg pain are more significant than those in leg numbness. Residual numbness could be related to the relatively low satisfaction rate. However, few studies have focused on numbness; thus, elucidating the risk factors and rate of residual numbness would benefit surgeons and patients. This study aimed to clarify the risk factors for and rate of residual numbness after decompression surgery.

PATIENTS AND METHODS

We retrospectively reviewed prospectively collected data from consecutive patients who underwent lumbar decompression without fusion for LSS at a single institution between January 2014 and March 2016. Patients were included if preoperative and final follow-up questionnaires and radiographs were available. A minimum one-year follow-up was required. We evaluated the Numeric Rating Scale (NRS) scores of low back pain, leg pain, and leg numbness preoperatively and at the final follow-up visit. Residual numbness was defined as a postoperative NRS ≥ 1, whereas persistent numbness was defined as a postoperative NRS ≥ 5. We compared the clinical data of patients with or without residual numbness to those of patients with or without persistent numbness. Multivariate logistic regression analysis was performed to identify risk factors for residual and persistent numbness.

RESULTS

A total of 116 patients (73 men, 43 women) were included. Of them, 60% had residual numbness with a mean follow-up period of 25 months. Only durotomy differed significantly between patients with and those without residual numbness. However, the significance did not persist after logistic regression analysis. A total of 16% had persistent numbness. Diabetes mellitus, intraoperative durotomy, and preoperative NRS of numbness were identified as risk factors. There were no differences in smoking status, presence of spondylolisthesis or scoliosis, or severity of stenosis.

CONCLUSIONS

We found three risk factors for persistent numbness following decompression surgery for LSS; diabetes mellitus and durotomy were modifiable, whereas preoperative numbness was not. Our findings would help surgeons minimize the incidence of persistent numbness by adequately controlling diabetes and avoiding durotomy during surgery. Providing information about the potential for residual numbness during the informed consent process is important to ensuring realistic patient expectations.

Natural language processing for automated detection of incidental durotomy

BACKGROUND

Incidental durotomy is a common intraoperative complication during spine surgery with potential implications for postoperative recovery, patient-reported outcomes, length of stay, and costs. To our knowledge, there are no processes available for automated surveillance of incidental durotomy.

PURPOSE

The purpose of this study was to develop natural language processing (NLP) algorithms for automated detection of incidental durotomies in free-text operative notes of patients undergoing lumbar spine surgery.

PATIENT SAMPLE

Adult patients 18 years or older undergoing lumbar spine surgery between January 1, 2000 and June 31, 2018 at two academic and three community medical centers.

OUTCOME MEASURES

The primary outcome was defined as intraoperative durotomy recorded in free-text operative notes.

METHODS

An 80:20 stratified split was undertaken to create training and testing populations. An extreme gradient-boosting NLP algorithm was developed to detect incidental durotomy. Discrimination was assessed via area under receiver-operating curve (AUC-ROC), precision-recall curve, and Brier score. Performance of this algorithm was compared with current procedural terminology (CPT) and international classification of diseases (ICD) codes for durotomy.

RESULTS

Overall, 1,000 patients were included in the study and 93 (9.3%) had a recorded incidental durotomy in the free-text operative report. In the independent testing set (n=200) not used for model development, the NLP algorithm achieved AUC-ROC of 0.99 for detection of durotomy. In comparison, the CPT/ICD codes had AUC-ROC of 0.64. In the testing set, the NLP algorithm detected 16 of 18 patients with incidental durotomy (sensitivity 0.89) whereas the CPT and ICD codes detected 5 of 18 (sensitivity 0.28). At a threshold of 0.05, the NLP algorithm had specificity of 0.99, positive predictive value of 0.89, and negative predictive value of 0.99.

CONCLUSIONS

Internal validation of the NLP algorithm developed in this study indicates promising results for future NLP applications in spine surgery. Pending external validation, the NLP algorithm developed in this study may be used by entities including national spine registries or hospital quality and safety departments to automate tracking of incidental durotomies.

How I do it: en-bloc subaxial cervical laminectomy using a high-speed drill with a footplate attachment

BACKGROUND

Cervical laminectomy is a common strategy to decompress the spinal canal.

METHODS

The anatomy of the cervical spine and surrounding critical structures as viewed from the posterior approach is described. The use of a high-speed drill with a footplate attachment to make laminar troughs with an en-bloc subaxial cervical laminectomy is described with a discussion on surgical technique and complication avoidance.

CONCLUSION

This technique allows for a safe, comfortable, and rapid decompression of the cervical spine with minimal risk. For routine cases, this may potentially be more safe and cost-effective than using a cutting bur or bone scalpel attachment.

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.

Decompressive surgery for Chiari I malformation in children without dural repair: a still effective and safe procedure?

PURPOSE

There are numerous publications about the technical aspects of decompressive surgery for Chiari I malformation highlighting many variations of this procedure. Each approach has its followers. Bony decompression of the foramen magnum alone or with the removal of a portion of the posterior arch of C1, dural splitting with keeping arachnoid intact, and durotomy are described. Dural closure is done with various materials. We retrospectively reviewed foramen magnum decompression without dural repair (FMDWDR) following the technique used by Gardener and Williams as an option in pediatric patients with Chiari I malformation in terms of complication rate and clinical outcome.

METHODS

The surgical database of our unit identified 65 consecutive children who underwent FMDWDR surgery for Chiari I malformation between 2009 and 2016. The retrospective assessment included patient demographics, clinical data, surgical technique, revision rate, complications, and clinical outcome.

RESULTS

Durotomy without repair was performed in 65 patients. Complications included aseptic meningitis and subdural hematoma respectively in three cases, intradiploic CSF collections in three patients, and CSF leaks in six children. The CSF leak rate has reduced dramatically after introducing a technical modification. Revision surgery was performed in seven cases. None of the patients was identified with postoperative hydrocephalus or infection. There was no mortality and no long-term surgical morbidity. In terms of clinical outcome, 52 patients reported postoperative improvement, 10 were clinically unchanged, and three noticed worsening of symptoms.

CONCLUSION

Applying a "T"-shaped fascial incision which allows a watertight closure of the fascia FMDWDR is still a safe and effective treatment option for Chiari I malformation in children.

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

BACKGROUND CONTEXT

Dural tear represents a common complication of microendoscopic spine surgery that may lead to postoperative sequelae including insufficient decompression, cerebrospinal fluid fistula, intracranial hypotension, and subdural/intraparenchymal bleeding. The gold standard to manage intraoperative dural tears is primary repair. However, the downside of conversion to open surgery can be detrimental. Therefore, understanding the most appropriate strategy for microendoscopic dural repair and its impact on postoperative outcomes is of importance.

PURPOSE

The purpose of this study was to investigate the incidence of dural tears in patients undergoing microendoscopic lumbar surgery and to elucidate their influence on surgical outcomes whenever proper repair is accomplished microendoscopically without conversion to open surgery.

STUDY DESIGN/SETTING

A retrospective multicenter cohort study of prospectively enrolled patients using a propensity-matched analysis.

PATIENT SAMPLE

A total of 922 consecutive patients underwent microendoscopic surgery of the lumbar spine between February and December 2012 in the three institutions belonging to our study group.

OUTCOME MEASURES

Outcome measures included the Numeric Rating Scale for back and leg pain, Oswestry Disability Index, Japanese Orthopaedic Association score, Short Form-36, and a patients' satisfaction scale.

METHODS

All incidental dural tears were repaired by microendoscopic suture of the dura mater from inside to outside using double-arm needles and/or by fibrin glue coverage without being converted to open surgery. Surgical outcomes were compared between patients with and without dural tears using a propensity-matched analysis.

RESULTS

Microendoscopic discectomy for lumbar disc herniation was performed on 474 patients, whereas microendoscopic laminectomy and posterior lumbar interbody fusion for lumbar canal stenosis were performed on 271 and 177 patients, respectively. Dural tears occurred in 49 (5.3%) patients. Of these, 23 (2.5%) patients required suture repair, whereas the rest received a fibrin patch for a pinhole tear, all of which were successfully performed under microendoscopy. Six hundred (65.1%) patients responded pre- and postoperatively to the questionnaire. Of them, the responses of 38 patients with dural tears were compared with those of 38 matched patients. No significant differences in any outcome measures were observed between the two groups.

CONCLUSIONS

In conclusion, all dural tears in our cases were managed without conversion to open surgery and did not influence surgical outcomes.

An Unusual Case of Transdural Herniation of a Lumbar Intervertebral Disc: Diagnostic and Surgical Challenges

BACKGROUND

Intradural lumbar disc herniation is rare, with an incidence of 0.3%-1%, but has been well reported in the literature. Transdural migration of the disc penetrating both ventral and dorsal dura is extremely rare, and there is a dearth of literature in the pathophysiology and surgical management of transdural herniation. Lack of knowledge on this type of presentation can cause intraoperative surprises and inadvertent cauda equina root injuries and lead to prolonged operative time. We report 1 such case, describe our surgical experience, and discuss the pathological mechanisms and signs.

CASE DESCRIPTION

A 30-year-old woman presented to outpatient clinic with chronic cauda equina syndrome due to massive L4-L5 disc herniation. L4-L5 decompression and transforaminal lumbar interbody fusion were planned. Unexpectedly, however, surgery revealed a transdural herniation, which was effectively managed with laminectomy, extension of durotomy, discectomy, repair of both dorsal and ventral dura, and interbody fusion, but at the expense of prolonged surgical time.

CONCLUSIONS

Transdural herniation of a lumbar disc is very rare presentation. It can be effectively managed with laminectomy, extension of durotomy, discectomy and repair of both dorsal and ventral dura. It can be diagnosed by magnetic resonance imaging preoperatively only if read with suspicion of such presentation.

Cerebrospinal fluid leaks after spine tumor resection: avoidance, recognition and management

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.

The evidence-based approach for surgical complications in the treatment of lumbar disc herniation

PURPOSE

The purpose of this article is to review the evidence-based approach for surgical complications following disc herniation.

METHODS

A search of the primary English literature was conducted for research examining the outcomes and complications of surgical discectomy. Special regard was given to high-quality prospective randomized studies.

RESULTS

The most commonly reported complications of surgical treatment of disc herniation are included in this review. Medical complications, and surgical complications including infection, durotomy, neurological injury, symptomatic re-herniation, and revision surgery are defined and systematically reviewed in detail for incidence, evaluation, and management.

CONCLUSION

This article provides the clinician and surgeon with a review of the evidence-based evaluation and management of surgical complications following disc herniation, offering best practice guidelines for informed discussions with patients in shared decision-making.

Late-presenting dural tear: incidence, risk factors, and associated complications

BACKGROUND CONTEXT

Unrecognized and inadequately repaired intraoperative durotomies may lead to cerebrospinal fluid leak, pseudomeningocele, and other complications. Few studies have investigated durotomy that is unrecognized intraoperatively and requires additional postoperative management (hereafter, late-presenting dural tear [LPDT]), although estimates of LPDT range from 0.6 to 8.3 per 1,000 spinal surgeries. These single-center studies are based on relatively small sample sizes for an event of this rarity, all with <10 patients experiencing LPDT.

PURPOSE

This investigation is the largest yet conducted on LPDT, and sought to identify incidence, risk factors for, and complications associated with LPDT.

STUDY DESIGN/SETTING

This observational cohort study employed the American College of Surgeons National Surgical Quality Improvement Program dataset (years 2012-2015).

PATIENT SAMPLE

Patients who underwent spine surgery were identified based on presence of primary listed Current Procedural Terminology (CPT) codes corresponding to spinal fusion or isolated posterior decompression without fusion.

OUTCOME MEASURES

The primary variable in this study was occurrence of LPDT, identified as reoperation or readmission with durotomy-specific CPT or International Classification of Diseases, Ninth Revision, Clinical Modification codes but without durotomy codes present for the index procedure.

METHODS

Descriptive statistics were generated. Bivariate and multivariate analyses were conducted using chi-square tests and multiple logistic regression, respectively, generating both risk factors for LPDT and independent association of LPDT with postoperative complications. Statistical significance was defined as p<.05.

RESULTS

In total, 86,212 patients were analyzed. The overall rate of reoperation or readmission without reoperation for LPDT was 2.0 per 1,000 patients (n=174). Of LPDT patients, 97.7% required one or more unplanned reoperations (n=170), and 5.7% of patients (n=10) required two reoperations. On multivariate analysis, lumbar procedures (odds ratio [OR] 2.79, p<.0001, vs. cervical), procedures involving both cervical and lumbar levels (OR 3.78, p=.0338, vs. cervical only), procedures with decompression only (OR 1.72, p=.0017, vs. fusion and decompression), and operative duration ≥250 minutes (OR 1.70, p=.0058, vs. <250 minutes) were associated with increased likelihood of LPDT. Late-presenting dural tear was significantly associated with surgical site infection (SSI) (OR 2.54, p<.0001), wound disruption (OR 2.24, p<.0001), sepsis (OR 2.19, p<.0001), thromboembolism (OR 1.71, p<.0001), acute kidney injury (OR 1.59, p=.0281), pneumonia (OR 1.14, p=.0269), and urinary tract infection (UTI) (OR 1.08, p=.0057).

CONCLUSIONS

Late-presenting dural tears occurred in 2.0 per 1,000 patients who underwent spine surgery. Patients who underwent lumbar procedures, decompression procedures, and procedures with operative duration ≥250 minutes were at increased risk for LPDT. Further, LPDT was independently associated with increased likelihood of SSI, sepsis, pneumonia, UTI, wound dehiscence, thromboembolism, and acute kidney injury. As LPDT is associated with markedly increased morbidity and potential liability risk, spine surgeons should be aware of best-practice management for LPDT and consider it a rare, but possible etiology for developing postoperative complications.

Incidental durotomy in decompression for lumbar spinal stenosis: incidence, risk factors and effect on outcomes in the Spine Tango registry

PURPOSE

The three aims of this Spine Tango registry study of patients undergoing decompression for spinal stenosis were to: report the rate of dural tear (DT) stratified by treatment centre; find factors associated with an increased likelihood of incurring a DT; and compare treatment outcomes in relation to DT (none vs. repaired vs. unrepaired DT).

METHODS

Multivariate logistic regression was used to assess the association between DT and patient and treatment characteristics. Patient-rated and surgical outcomes were compared in patients with no DT, repaired DT, and unrepaired DT, while adjusting for case-mix.

RESULTS

DT occurred in 328/3254 (10.1%) of included patients. The rate for all 29 contributing hospitals was within 95% confidence intervals of the average. The likelihood of DT increased by 2% per year of age, 1.78 times with previous spine surgery, 1.67 for a minimally/less invasive surgery, 1.58 times with laminectomy, and 1.40, and 2.12 times for BMI 31-35, and >35 in comparison with BMI 26-30, respectively. The majority of DTs (272/328; 82.9%) were repaired. Repairing the DT was associated with a longer duration of surgery (p < 0.001). More patients with repaired than with unrepaired DTs were satisfied with treatment, but the difference was not statistically significant. There was no association between DT and patient-reported outcomes.

CONCLUSION

The unadjusted rate of incidental DT during decompression for LSS was homogeneous across the participating centres and was associated with age, BMI, previous surgery at the same spinal level, minimally/less invasive surgery, and laminectomy. Non-repair of DTs had no negative association with treatment outcome; however, the unrepaired DTs may have been those that were smaller in size.

Intraspinal Pressure Monitoring and Extensive Duroplasty in the Acute Phase of Traumatic Spinal Cord Injury: A Systematic Review

OBJECTIVE

The prognosis in cervical spinal cord injury is poor, and surgical and neurointensive care management need further improvement. Monitoring of the intraspinal pressure (ISP) at an early stage after traumatic spinal cord injury (tSCI) is useful clinically.

MATERIALS AND METHODS

Obtaining continuous spinal cord perfusion pressure (SCPP) measurements based on the difference between mean arterial pressure and ISP allows offering best medical and surgical treatment during this critical phase of tSCI. A search was carried out with PubMed, Embase, and Google Scholar up to January 10, 2017. Articles resulting from these searches and relevant references cited in those articles were reviewed.

RESULTS

The optimal SCPP was found to be between 90 and 100 mm Hg and mean arterial pressure of 110-130. Laminectomy alone was found to be ineffective in the reduction of ISP because it does not lower the pressure exerted by dura on the swollen spinal cord. Therefore, bony decompression with durotomy or duroplasty seems to be the procedure of choice to reduce the ISP less than 20 mm Hg.

CONCLUSIONS

A randomized controlled trial is required to determine whether laminectomy with durotomy and monitoring of ISP with SCPP optimization improve neurological recovery after tSCI.

A method of posterior fossa dural incision to minimize hemorrhage from the occipital sinus: the "mosquito" method

PURPOSE

The posterior fossa dural opening requires the ligation of the occipital sinus to gain successful exposure. However, there could be a prominent occipital sinus which is functioning as the main drainage route and is harboring the risk of unpredictable massive hemorrhage during the dural opening. We introduce a safe method of posterior fossa dural incision to minimize hemorrhage from the occipital sinus using four curved hemostat clamps.

METHODS

For the dural incision at the midline part of the posterior cranial fossa, we used four curved hemostat clamps to occlude the prominent occipital sinus: one pair of clamps at the proximal part and the other pair at the distal part to occlude the occipital sinus. Dural incision was made between the two pairs of the curved hemostat clamps.

RESULTS

By clamping of the sinus, it allows observation of possible brain swelling after occlusion of the occipital sinus as well as minimizes hemorrhage during incision of the midline dura of the posterior fossa.

CONCLUSION

This method allows observation of brain swelling after occipital sinus occlusion and is an easy and safe incision of the midline dura minimizing hemorrhage in selected cases with a prominent occipital sinus.

Complications of surgical intervention in adult lumbar scoliosis

If nonoperative measures are unsuccessful in managing the pain and disability of adult spinal deformities, surgical correction may provide the potential for significant improvement in a patient's quality of life. However, these procedures have a relatively high risk of complications. Identifying patients that may benefit from surgical intervention requires a thorough understanding of potential complications and managing the risks of any individual patient. Complications do not necessarily result in poor outcomes, and good outcomes are not always complication free. Higher risk patients potentially have more to gain, even if they experience complications. With the rapidly expanding senior population and expanded capabilities to manage high-risk patients, it is helpful to consider the lessons provided by ever expanding databases of outcome measures to refine the surgical decision-making process.

The impact of incidental durotomy on the outcome of decompression surgery in degenerative lumbar spinal canal stenosis: analysis of the Lumbar Spinal Outcome Study (LSOS) data--a Swiss prospective multi-center cohort study

Background

Incidental durotomy is a well-known complication during surgery for degenerative lumbar spinal stenosis (DLSS). In this prospective multicenter cohort study including eight medical centers our aim was to assess whether incidental durotomy during first-time lumbar spinal stenosis decompression surgery without fusion has an impact on long-term outcome.

Methods

Patients of the multi-center Lumbar Stenosis Outcome Study (LSOS) with confirmed DLSS undergoing first-time decompression without fusion were enrolled in this study. Baseline patient characteristics and outcomes were analyzed at 6, 12, and 24 months follow-up respectively with the Spinal Stenosis Measure (SSM), the Numeric Rating Scale (NRS), Feeling Thermometer (FT), the EQ-5D-EL, and the Roland and Morris Disability Questionnaire (RMDQ).

Results

A total of 167 patients met the inclusion criteria. Fifteen (9 %) of those patients had an incidental durotomy. Baseline characteristics were similar between the durotomy and no-durotomy group. All patients improved over time. In the group of durotomy patients, the median improvement in SSM symptoms scale was 1.1 points at 6 months, 1.1 points at 12 months, and 1.6 points at 24 months after baseline. For the no-durotomy group, these improvements were 0.8, 0.9, and 0.9. For SSM function the improvements were 1.0, 0.8, and 0.9 in the durotomy group, and 0.6, 0.8, and 0.8 in the no-durotomy group. None of the between-group differences were statistically significant.

Conclusions

Incidental durotomy in patients with DLSS undergoing first-time decompression surgery without fusion did not have negative effect on long-term outcome and quality of life. However, only 15 patients were included in the durotomy group but these findings remained even after adjusting for observed differences in baseline characteristics.

Durotomy repair in minimally invasive transforaminal lumbar interbody fusion by nonpenetrating clips

Background:

Closure of the dura defect may be easy to perform in open lumbar surgery but could be difficult in minimally invasive transforaminal lumbar interbody fusions (MIS-TLIF) since MIS-TLIF was done through a small tube, which limited the use of standard dural repair instruments. We used nonpenetrating titanium clips that were originally designed for the vascular anastomoses to repair the dura defect, which is never described in the literature.

Methods:

We presented a case of spinal stenosis with incidental durotomy while performing MIS-TLIF. We closed the dura laceration with three medium-sized nonpenetrating titanium clips (AnastoClip Vessel Closure System, LeMaitre Vascular, Inc., Burlington, MA).

Results:

Nonpenetrating titanium clips have the benefits of being technically easy to use, reduced durotomy repair time, decreased bed rest due to related medical complications, superior postoperation with immediate hydrostatic strength, and better reapproximation if it fails to clip successfully. As for the postoperation follow up, clips are tiny and reveal no obvious artifact, especially in cases where the pedicle screws are already causing much artifact.

Conclusion:

Primary dural closure during MIS-TLIF with clips is an effective way in cases that involve limited tubular space.

Comparison of symptomatic cerebral spinal fluid leak between patients undergoing minimally invasive versus open lumbar foraminotomy, discectomy, or laminectomy

OBJECTIVE

Minimally invasive spine surgery (MISS) techniques have similar long-term outcomes compared to open surgery for patients undergoing 1- or 2-level discectomy, foraminotomy, or laminectomy. However, the rate of cerebrospinal fluid (CSF) leaks with both techniques has not been well established in the literature. This study sought to compare the rate and clinical impact of CSF leak in open lumbar foraminotomy, discectomy, or laminectomy with comparable MISS approaches.

METHODS

A total of 863 patients undergoing 1- or 2-level discectomy, foraminotomy, or laminectomy by either MISS an open technique were evaluated for CSF leaks. Variables assessed included operative time, blood loss, CSF leaks, hospital stay, days with lumbar drain, days of postoperative flat bed rest, and postoperative intervention. Statistical analyses include univariate analysis (Student t test, analysis of variance, odds ratio, χ(2)) and bivariate analysis (logistic regression).

RESULTS

In the MISS group there were 15 CSF leaks (4.7%), and 49 CSF leaks (9.0%) in the open group. Eight patients in the open group required lumbar drainage, compared to zero patients in the MISS group. Twelve patients required reoperation for persistent CSF leak in the open group, compared to zero patients in the MISS group. Patients undergoing open spine surgery were 2 times more likely to have a CSF leak (odds ratio = 2.3, 95% confidence interval = 1.2 to 3.7, P = .01). Patients undergoing MISS had significantly lower reoperation rates for CSF leak repairs (open = 25% of open CSF leak cases, MISS = 0%, P < .01).

CONCLUSIONS

In this study, there was a statistically significant decreased rate of CSF leak between an MISS approach and an open surgical approach. Furthermore, CSF leaks in open surgery have a higher probability of requiring lumbar drainage or reoperation to repair the durotomy.