Dural tears in spine surgery

The Use of Cranial Aneurysm Clips for Repair of Incidental Lumbar Durotomy: Operative Technique and Case Series

BACKGROUND

Incidental durotomy is a common complication of posterior lumbar spine surgery; however, effective and durable methods for primary repair remain elusive. Multiple existing techniques have previously been reported and extensively described, including sutured repair and the use of nonpenetrating titanium clips. The use of cranial aneurysm clips for primary repair of lumbar durotomy serves as a safe and effective alternative to obtain watertight closure of a dural tear.

METHODS

We performed a retrospective review of patients at a single institution who underwent primary repair of an incidental lumbar durotomy with the use of an aneurysm clip during open posterior lumbar surgery between 2012 and 2023. Patient demographics, operative details, and postoperative metrics were collected and examined to evaluate the safety and efficacy of the novel technique.

RESULTS

A total of 51 patients were included for analysis. Four patients underwent durotomy repair with an aneurysm clip alone, 27 patients were repaired with an aneurysm clip and fibrin glue, and 20 patients underwent repair with an aneurysm clip, fibrin glue, and a collagen dural substitute. Three patients (5.9%) reported headaches: 2 (3.9%) with pseudomeningocele and 1 (2%) with wound leakage. Two patients (3.9%) had treatment failure with a return to the operating room for repair of a cerebrospinal fluid leak.

CONCLUSIONS

To the best of our knowledge, we report the largest series of patients undergoing primary repair of incidental durotomy with the use of an aneurysm clip. Use of an aneurysm clip is noted to be a safe, quick, and effective method of primary repair compared with existing repair techniques such as sutured repair or nonpenetrating titanium clips.

Comparison of dural closure methods for dural repair to reduce the incidence of cerebrospinal fluid leakage

PURPOSE

Cerebrospinal fluid leakage (CSFL) is a common complication during spinal surgery. This study aimed to compare dural closure with different suture types, sizes, and techniques, and adhesives to reduce the occurrence of CSFL.

MATERIALS AND METHODS

Using a pig spine model, the PDS II 4-0, 5-0, 6-0, Vicryl 4-0, 5-0, 6-0, and Prolene 4-0, 5-0, 6-0 sutures were compared by calculating the permeability after suturing. Spraying bioprotein glue was also tried. Next, 120 patients who underwent surgery for intraspinal subdural tumors were enrolled and received 5-0 PDSII, Vicryl, or Prolene for dura repair.

RESULTS

In the animal model study, Vicryl 5-0 showed a reduced leakage flow rate compared with 5-0 Prolene and 5-0 PDS II. In the clinical study, postoperative drainage in the Vicryl group was smaller than that in the other groups during the first 3 days after surgery (p < 0.05). Drainage volume of patients with postoperative cerebrospinal fluid leakage in the Vicryl group was smaller than that in the other groups during the first 3 days after surgery (p < 0.05). There were 12 patients (23.1%, 12/52) in the Vicryl group, 20 patients (55.6%, 20/36) in the PDS group, and 16 patients (50.0%, 16/32) in the Prolene group who had CSFL.The incidence of CSFL was significantly reduced in Vicryl group compared with the other groups(P < 0.05).

CONCLUSIONS

5-0 Vicryl sutures significantly reduced the dural leakage flow rate in an animal spine model. Fibrin glue can reinforce dural repair after surgery. 5-0 Vicryl was associated with a lower occurrence of CSFL in patients.

A Subdural Dissection of Cerebrospinal Fluid Causing Cauda Equina Centralization After Durotomy: A Case Report

CASE

A 61-year-old woman with recurrent left L5 radiculopathy underwent revision L4-5 decompression complicated by incidental durotomy requiring primary repair. Postoperative course was complicated by wound drainage and headache. Repeat magnetic resonance imaging demonstrated cerebrospinal fluid dissecting a plane deep to the dura mater but superficial to the arachnoid, with the collection compressing the cauda equina in an atypical horizontal and linear fashion. Nonoperative treatment was ineffective, and she required revision decompression and dural repair.

CONCLUSION

Spine surgeons should recognize this finding on postoperative imaging as a potential sign of an incomplete dural repair necessitating return to the operating room.

The Role of Prolonged Bed Rest in Postoperative Cerebrospinal Fluid Leakage After Surgery of Intradural Pathology-A Retrospective Cohort Study

BACKGROUND

Postoperative cerebrospinal fluid leakage (CSFL) is a feared complication after surgery on intradural pathologies and may cause postoperative complications and subsequently higher treatment costs.

OBJECTIVE

To assess whether prolonged bed rest may lower the risk of CSFL.

METHODS

We performed a retrospective cohort study including patients with intradural pathologies who underwent surgery at our department between 2013 and 2021. Cohorts included patients who completed 3 days of postoperative bed rest and patients who were mobilized earlier. The primary end point was the occurrence of clinically proven CSFL.

RESULTS

Four hundred and thirty-three patients were included (female [51.7%], male [48.3%]) with a mean age of 48 years (SD ±20). Bed rest was ordered in 315 cases (72.7%). In 7 cases (N = 7/433, 1.6%), we identified a postoperative CSFL. Four of them (N = 4/118) did not preserve bed rest, showing no significant difference to the bed rest cohort (N = 3/315; P = .091). In univariate analysis, laminectomy (N = 4/61; odds ratio [OR] 8.632, 95% CI 1.883-39.573), expansion duraplasty (N = 6/70; OR 33.938, 95% CI 4.019-286.615), and recurrent surgery (N = 5/66; OR 14.959, 95% CI 2.838-78.838) were significant risk factors for developing CSFL. In multivariate analysis, expansion duraplasty was confirmed as independent risk factor (OR 33.937, 95% CI 4.018-286.615, P = .001). In addition, patients with CSFL had significant higher risk for meningitis (N = 3/7; 42.8%, P = .001).

CONCLUSION

Prolonged bed rest did not protect patients from developing CSFL after surgery on intradural pathologies. Avoiding laminectomy, large voids, and minimal invasive approaches may play a role in preventing CSFL. Furthermore, special caution is indicated if expansion duraplasty was done.

Incidence, Risk Factors, and Outcomes of Incidental Durotomy during Lumbar Spine Decompression with or without Fusion

STUDY DESIGN

Retrospective cohort study.

PURPOSE

The primary objective of this study was to determine the incidence and risk factors for incidental durotomies during lumbar decompression surgeries. In addition, we aimed to determine the changes in patient-reported outcome measures (PROMs) based on incidental durotomy status.

OVERVIEW OF LITERATURE

There is limited literature investigating the affect of incidental durotomy on patient reported outcome measures. While the majority of research does not suggest differences in complications, readmission, or revision rates, many studies rely on public databases, and their sensitivity and specificity for identifying incidental durotomies is unknown.

METHODS

Patients undergoing lumbar decompression with or without fusion at a single tertiary care center were grouped based on the presence of a durotomy. Multivariate analysis was performed for length of stay (LOS), hospital readmissions, and changes in PROMs. To identify surgical risk factors for durotomy, 3:1 propensity matching was performed using stepwise logistic regression. The sensitivity and specificity of the International Classification of Disease, 10th revision (ICD-10) codes (G96.11 and G97.41) were also assessed.

RESULTS

Of the 3,684 consecutive patients who underwent lumbar decompressions, 533 (14.5%) had durotomies, and a complete set of PROMs (preoperative and 1-year postoperative) were available for 737 patients (20.0%). Incidental durotomy was an independent predictor of increased LOS but not hospital readmission or worse PROMs. The durotomy repair method was not associated with hospital readmission or LOS. However, repair with collagen graft and suture predicted reduced improvement in Visual Analog Scale back (β =2.56, p=0.004). Independent risk factors for incidental durotomies included revisions (odds ratio [OR], 1.73; p<0.001), levels decompressed (OR, 1.11; p=0.005), and preoperative diagnosis of spondylolisthesis or thoracolumbar kyphosis. The sensitivity and specificity of ICD-10 codes were 5.4% and 99.9%, respectively, for identifying durotomies.

CONCLUSIONS

The durotomy rate for lumbar decompressions was 14.5%. No differences in outcomes were detected except for increased LOS. Database studies relying on ICD codes should be interpreted with caution due to the limited sensitivity in identifying incidental durotomies.

Dural injury following elective spine surgery - A prospective analysis of risk factors, management and complications

Incidental dural tears being a familiar complication in spine surgery could result in dreaded postoperative outcomes. Though the literature pertaining to their incidence and management is vast, it is limited by the retrospective study designs and smaller case series. Hence, we performed a prospective study in our institute to determine the incidence, surgical risk factors, complications and surgical outcomes in patients with unintended durotomy during spine surgery over a period of one year. The overall incidence in our study was 2.3% (44/1912). Revision spine surgeries in particular had a higher incidence of 16.6%. The average age of the study population was 51.6 years. The most common intraoperative surgical step associated with dural tear was removal of the lamina, and 50% of the injuries were during usage of kerrison rongeur. The most common location of the tear was paramedian location (20 patients) and the most common size of the tear was about 1 mm-5mm (31 patients). We observed that the dural repair techniques, placement of drain and prolonged post-operative bed rest didnot significantly affect the post-operative outcomes. One patient in our study developed persistent CSF leak, which was treated by subarachnoid lumbar drain placement. No patients developed pseudomeningocele or post-operative neurological worsening or re-exploration for dural repair. Wound complications were noted in 4 patients and treated by debridement and antibiotics. Based on our study, we have proposed a treatment algorithm for the management of dural tears in spine surgery.

The utility of the CADISS® system in the dissection of epidural fibrosis in revision lumbar spine surgery (A case series)

Spine surgery and spinal fusion surgery are rising. Revision rates following initial surgery are between 8 and 45%. Epidural fibrosis is a common response to spine surgery for most patients and increases complications in revision surgery. Previous research suggests using MESNA (Sodium 2-mercaptoethane sulfonate) in combination with mechanical blunt dissection safely reduces surgical complications. MESNA is a mucolytic agent which selectively cleaves disulphide bonds involved in the adherence and strength of fibrosis, meaning cutting instruments are not needed. The Chemically Assisted DISSection (CADISS®) System is an optimised non-cutting surgical device, consisting of a reconstitution cartridge for MESNA preparation, irrigated surgical instruments, and a footswitch to control MESNA release. This is the first study to investigate the use of the CADISS® System in revision spine surgery.

Methods

This was a prospective, open label, observational case study. We enrolled 21 patients for revision spine surgery with the CADISS® System at two Belgium sites. The primary assessment was the number of successful removals of epidural fibrosis without cutting. The amount of MESNA used, total dissection and procedure time were recorded. For secondary criterion, the surgeons assessed global satisfaction, facilitation of dissection, quickness of action, usability, bleeding reduction and visualisation of the cleavage plane using an 11-point Likert scale (0–10). Due to the exploratory nature, no formal statistical analysis was planned. We calculated the percentage and confidence interval of successful procedures, the medians and corresponding interquartile range of the Likert criterion, and the mean (±SD) of the amount of MESNA used, CADISS® dissection time and total procedure time.

Results

24 fibrosis dissections were performed in 19 patients and 23 were successful (95.8%, CI: 78.9%; 99.9%). The mean amount of MESNA used, mean dissection time and procedure time were 16 ml (±4.94), 16.5 min (±16.1) and 86.3 min (±25.1), respectively. No dural tears were reported. The mean global satisfaction score was 9.0 (8.0–9.0). All other Likert criterion had scores of 8.0 or 9.0, excluding quickness of action, which scored 7.0 (6.0–9.0).

Conclusions

The CADISS® System in revision spine surgery has potential to effectively reduce dissection complications.

•

Revision rates following initial surgery are between 8 and 45%. Epidural fibrosis is a common response to spine surgery for most patients and increases complications in revision surgery.

•

Previous research suggests using MESNA (Sodium 2-mercaptoethane sulfonate) in combination with mechanical blunt dissection safely reduces surgical complications. MESNA is a mucolytic agent which selectively cleaves disulphide bonds involved in the adherence and strength of fibrosis, meaning cutting instruments are not needed. The Chemically Assisted DISSection (CADISS®) System is an optimised non-cutting surgical device, consisting of a reconstitution cartridge for MESNA preparation, irrigated surgical instruments, and a footswitch to control MESNA release.

•

We enrolled 21 patients for revision spine surgery with the CADISS® System at two Belgium sites. The primary assessment was the number of successful removals of epidural fibrosis without cutting. The CADISS® System in revision spine surgery has potential to effectively reduce dissection complications.

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.

Can Cervical and Lumbar Epidural Blood Patches Help Avoid Revision Surgery for Symptomatic Postoperative Dural Tears?

BACKGROUND

Incidental durotomies resulting in symptomatic postoperative cerebrospinal fluid (CSF) leaks can be treated with bedrest, subarachnoid lumbar drain, and surgical re-exploration. Another option is an epidural blood patch, which forms a clot over the dural tear in a minimally invasive manner. Our objective was to describe our center's outcomes and complications following epidural blood patches for symptomatic postoperative durotomies.

METHODS

Patients undergoing spine surgeries at one institution from 2012-2020 were included. Patient charts were reviewed for demographic information, surgical data, rate of dural tear, type of repair, and use of blood patches postoperatively.

RESULTS

A total of 1392 patients (726 male, 666 female, average age: 56.3 ± 15.4 years), including 436 cervical and 956 posterior thoracolumbar/lumbar spine surgeries were screened. There were 6 (1.4%) cervical, 64 (6.7%) lumbar, and a total of 70 (5.0%) patients with incidental dural tears/blebs. Of these patients, we identified 2 cervical and 8 lumbar spine patients with persistent CSF leaks who received epidural blood patches postoperatively. Nine of 10 (90%) had resolution of symptoms. One lumbar patient failed both an initial blood patch and subsequent surgical re-exploration, but had successful relief after a second blood patch.

CONCLUSIONS

The incidence of dural tears/blebs was 1.4% in cervical, 6.7% in lumbar, and 5.0% in all spine surgeries. Of the 10 patients with symptomatic CSF leaks, 9 were successfully treated with blood patches. Targeted epidural blood patch is effective in treating symptomatic CSF leaks and minimizes the morbidity of surgical re-exploration.

Traumatic Spondyloptosis: Neurological, Surgical, and Outcome Perspectives in a Tertiary Care Center

Objective To evaluate traumatic spondyloptosis cases for neurological, surgical, and outcome perspectives.

Materials and Methods This retrospective study includes 17 patients of spondyloptosis admitted in our department between August 2016 and January 2020. Each patient was evaluated in terms of demographic profile, clinical presentation, duration of injury, mode of injury, associated injuries, level and type of spondyloptosis, spinal cord status, nociceptive and neuropathic pain severity, severity of injury based on International Standards for Neurological Classification of Spinal Cord Injury (ISNCSI) assessment, surgical approaches, complications, and outcome. Unpaired t- test and Chi-square test were used for statistical analysis. Values with p < 0.05 were considered statistically significant.

Results Fall from height (58.8%) was the most common mode of injury. Most common level of spondyloptosis was T12–L1 (41.1%). Sagittal–plane spondyloptosis (76.5%) were more common than coronal–plane spondyloptosis (23.5%). Most common associated injury was musculoskeletal (64.7%). Neurological status of the patient at presentation (p = 0.0007) was significantly associated with outcome after 3 months of surgery/conservative management. Residual listhesis was present in 53.3% of patients postoperatively. Postoperative nociceptive pain (p = 0.0171) and neuropathic pain (0.0329) were significantly associated with residual listhesis. Duration of injury (p = 0.0228) was also significantly associated with postoperative residual listhesis.

Conclusion Complete reduction of spondyloptosis should be the goal of surgery. Overall prognosis of spinal cord injury (SCI) due to traumatic spondyloptosis is poor.

Dural tear repair surgery comparative analysis: a stitch in time saves nine

PURPOSE

A dural tear is a common iatrogenic complication of spinal surgery associated with a several post-operative adverse events. Despite their common occurrence, guidelines on how best to repair the defect remain unclear. This study uses five post-operative outcomes to the compare repair methods used to treat 106 dural tears to determine which method is clinically favourable.

METHODS

Data were retrospectively collected from Southampton General Hospital's online databases. 106 tears were identified and grouped per repair method. MANOVA was used to compare the following five outcomes: Length of stay, numbers of further admissions or revision surgeries, length of additional admissions, post-operative infection rate and dural tear associated neurological symptoms. Sub-analysis was conducted on patient demographics, primary vs non-primary closure and type of patch. Minimal clinically important difference (MCID) was calculated via the Delphi procedure.

RESULTS

Age had a significant impact on patient outcomes and BMI displayed positive correlation with three-fifth of the predefined outcome measures. No significant difference was observed between repair groups; however, primary closure ± a patch achieved an MCID percentage improvement with regards to length of original stay, rate of additional admissions/surgeries and post-operative infection rate. Artificial over autologous patches resulted in shorter hospital stays, fewer readmissions, infections and neurological symptoms.

CONCLUSION

This study reports primary closure ± dural patch as the most efficient repair method with regards to the five reported outcomes. This study provides limited evidence in favour of artificial over autologous patches and recommends that dural patches be used in conjunction with primary closure.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

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.

High efficacy of tetra-PEG hydrogel sealants for sutureless dural closure

Advances in meticulous dural closure technique remain a great challenge for watertight dural closure in the aged society, because the cerebrospinal fluid (CSF) leakage after spinal surgery is often accompanied with the disgusting wound infection, meningitis and pseudomeningocele. Here, a tetra-poly (ethylene glycol) (PEG)-based hydrogel sealant is developed with collective advantages of facile operation, high safety, quick set time, easy injectability, favorable mechanical strength and powerful tissue adhesion for effective sutureless dural closure during the surgery procedure. Impressively, this tetra-PEG sealant can instantaneously adhere to the irregular tissue surfaces even in a liquid environment, and effectively prevent or block off the intraoperative CSF leakage for sutureless dural closure and dura regeneration. Together, this sutureless tetra-PEG adhesive can be utilized as a very promising alternative for high-efficient watertight dural closure of the clinical patients who incidentally or deliberately undergo the durotomy during the spinal surgery.

Reliability of Early Ambulation after Intradural Spine Surgery : Risk Factors and a Preventive Method for Cerebrospinal Fluid Leak Related Complications

Objective

Cerebrospinal fluid leakage related complications (CLC) occasionally occur after intradural spinal surgery. We sought to investigate the effectiveness of early ambulation after intradural spinal surgery and analyze the risk factors for CLC.

Methods

For this retrospective cohort study, we enrolled 314 patients who underwent intradural spinal surgery at a single institution. The early group contained 79 patients who started ambulation after 1 day of bedrest without position restrictions, while the late group consisted of 235 patients who started ambulation after at least 3 days of bed rest and were limited to the prone position after surgery. In the early group, Prolene 6–0 was used as the dura suture material, while black silk 5–0 was used as the dura suture material in the late group.

Results

The overall incidence rate of CLC was 10.8%. Significant differences between the early and late groups were identified in the rate of CLC (2.5% vs. 13.6%), surgical repair required (1.3% vs. 7.7%), and length of hospital stay (2.99 vs. 9.29 days) (p<0.05). Logistic regression analysis revealed that CLC was associated with practices specific to the late group (p=0.011) and the revision surgery (p=0.022).

Conclusion

Using Prolene 6–0 as a dura suture material for intradural spinal surgery resulted in lower CLC rates compared to black silk 5–0 sutures despite a shorter bed rest period. Our findings revealed that suture - needle ratio related to dura defect was the most critical factor for CLC. One-day ambulation after primary dura closure using Prolene 6–0 sutures appears to be a cost-effective and safe strategy for intradural spinal surgery.

Ultrafast laser surgery probe with a calcium fluoride miniaturized objective for bone ablation

We present a miniaturized ultrafast laser surgery probe with improved miniaturized optics to deliver higher peak powers and enable higher surgical speeds than previously possible. A custom-built miniaturized CaF2 objective showed no evidence of the strong multiphoton absorption observed in our previous ZnS-based probe, enabling higher laser power delivery to the tissue surface for ablation. A Kagome fiber delivered ultrashort pulses from a high repetition rate fiber laser to the objective, producing a focal beam radius of 1.96 μm and covering a 90×90 μm2 scan area. The probe delivered the maximum available fiber laser power, providing fluences >6 J/cm2 at the tissue surface at 53% transmission efficiency. We characterized the probe's performance through a parametric ablation study on bovine cortical bone and defined optimal operating parameters for surgery using an experimental- and simulation-based approach. The entire opto-mechanical system, enclosed within a 5-mm diameter housing with a 2.6-mm diameter probe tip, achieved material removal rates >0.1 mm3/min, however removal rates were ultimately limited by the available laser power. Towards a next generation surgery probe, we simulated maximum material removal rates when using a higher power fiber laser and found that removal rates >2 mm3/min could be attained through appropriate selection of laser surgery parameters. With future development, the device presented here can serve as a precise surgical tool with clinically viable speeds for delicate applications such as spinal decompression surgeries.

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.

Percutaneous Endoscopic Lumbar Discectomy Versus Microdiscectomy for the Treatment of Lumbar Disc Herniation: Pain, Disability, and Complication Rate-A Randomized Clinical Trial

Purpose

The objective was to compare the traditional microdiscectomy with percutaneous endoscopic lumbar discectomy for the treatment of disc herniations regarding pain, disability, and complications.

Methods

Randomized clinical trial with 47 patients with disc herniations treated with 2 different surgical techniques: traditional microdiscectomy or percutaneous endoscopic lumbar discectomy. Forty-seven patients were divided into 2 groups and monitored for 12 months. Irradiated and low back pain were evaluated with the visual analog scale. Surgery complications were recorded.

Results

After surgery, the sciatica and disability improved significantly but without significant differences between the groups. Improvements in back pain were significant until the third month. There were no statistical differences between groups regarding recurrence, infection, and the need for reoperation.

Conclusions

Endoscopic discectomy results are similar to those of conventional microdiscectomy regarding pain and disability improvement. Postoperative lumbar pain is less intense with endoscopic discectomy than conventional microdiscectomy only during the first 3 months. Endoscopic discectomy is a safe and efficient alternative to microdiscectomy.

Clinical Trials

Trial protocol registration number: RBR-5symrd (http://www.ensaiosclinicos.gov.br).

Minimizing CSF Leak and Wound Complications in Tethered Cord Surgery with Prone Positioning: Outcomes in 350 Patients

BACKGROUND

We document the results of a protocol to reduce the incidence of cerebrospinal fluid (CSF) leak and other wound complications in patients undergoing tethered cord surgery (TCS).

METHODS

Data from all patients undergoing TCS between January 2009 and April 2019 were reviewed retrospectively. Diagnosis (high risk or low risk; based on the presence of fascial and dural defects at surgery), type of graft used for dural or fascial repair, and CSF leak and other wound complications in the postoperative period were noted. All patients were nursed in the prone position with elevation of the foot end of the bed (Trendelenburg position) for at least 5 days after surgery with a subfascial drain in place.

RESULTS

Of a total of 350 patients (191 high risk; 159 low risk), CSF leak from the wound was noted in 16 (4.5%). All but 4 of these patients were managed with wound suturing with or without insertion of a subcutaneous drain with continued nursing in the prone and Trendelenburg position. Two patients had meningitis and 3 patients had wound infection. Multivariate analysis revealed that the use of synthetic grafts (P < 0.000) and inability to close the dura (P = 0.02) were the only significant risk factors for CSF wound leak. Wound infections and/or dehiscence were noted in 17 (4.8%) other patients.

CONCLUSION

Postoperative prone nursing with Trendelenburg position minimizes the incidence of CSF leak and other wound complications.

Spinal subdural hygroma as a post-operative complication in revision spine fusion: a case report

Lumbar spine fusion has become a common and effective procedure in orthopedic practice, and a spinal subdural hygroma development is a rare complication following this procedure. We report here the case of a revision lumbar spine fusion at levels L4-5, L5-S1, where the patient subsequently developed cauda equina syndrome 2 days post-operatively. Magnetic resonance imaging (MRI) showed a subdural, extra-arachnoid fluid collection from T12-L2, cephalad to the site of spine fusion. It appears the first case reported a subdural hygroma developed cephalad to the site of spine fusion. When a patient complains of radicular pain along with urinary retention and neurologic deficits post-lumbar spine surgery, cauda equina syndrome possibly caused by subdural hygroma should be considered. This warrants immediate MRI and emergent reoperation to relieve the pressure on the spinal cord may be necessary.

Simulation of Dural Repair in Minimally Invasive Spine Surgery With the Use of a Perfusion-Based Cadaveric Model

BACKGROUND AND IMPORTANCE

In an era of curtailed work hours and concerns over achieving technical proficiency in the repertoire of procedures necessary for independent practice, many residencies have turned to model simulation as an educational adjunct. Cerebrospinal fluid (CSF) leak repair after inadvertent durotomy in spine surgery is a fundamental skillset for any spine surgeon. While primary closure with suture is not always necessary for small durotomies, larger defects, on the other hand, must be repaired. However, the dire consequences of inadequate repair dictate that it is generally performed by the most experienced surgeon. Few intraoperative opportunities, therefore, exist for CSF leak repair by trainees.

OBJECTIVE

To simulate dural repair in spine surgery using minimal-access techniques.

METHODS

A cohort of 8 neurosurgery residents was evaluated on their durotomy repair efforts in a perfusion-based cadaveric model.

RESULTS

Study participants demonstrated consistent improvement across trials, with a significant reduction in closure times between their initial (12 min, 7 sec ± 4 min, 43 sec) and final attempts (7 min, 4 sec ± 2 min, 6 sec; P = .02). Moreover, all trainees—irrespective of postgraduate year—were able to accomplish robust dural closures resistant to simulated Valsalva maneuvers. Participants reported high degrees of model realism and exhibited significant increases in postprocedure confidence scores.

CONCLUSION

Our results support use of perfusion-based simulation models as a complement to neurosurgery training, as it affords unrestricted opportunities for honing psychomotor skillsets when resident learning is increasingly being challenged by work-hour limitations and stricter oversight in the context of value-based healthcare.

Depression Increases the Rates of Neurological Complications and Failed Back Surgery Syndrome in Patients Undergoing Lumbar Spine Surgery

STUDY DESIGN

This was a retrospective database study.

OBJECTIVE

The aim of this study was to use a large sample to accurately determine risk factors and rates of neurological complications in patients undergoing commonly performed lumbar spine surgeries.

SUMMARY OF BACKGROUND DATA

Damage to neurological structures and failed back surgery syndrome (FBSS) are among the most feared complications of lumbar spine surgery. Despite the large impact on quality of life these complications have, reported rates of neurological complications vary immensely, ranging from 0.46% to 24%.

MATERIALS AND METHODS

Data were obtained for patients undergoing initial posterior lumbar interbody fusion, transforaminal lumbar interbody fusion, anterior lumbar interbody fusion, posterolateral fusion, discectomy, and laminectomy procedures from January 2007 to June 2015 covered by the nationwide insurance carrier Humana. Patient records were analyzed to determine rates of dural tear, damage to nervous tissue, cauda equina syndrome, neurogenic bowel/bladder, and FBSS following each procedure. Rates were determined for patients undergoing single/multilevel procedures, by age, and for patients with a previous diagnosis of depression to determine the influence these factors had on the risk of neurologic complications.

RESULTS

Analysis of 70,581 patient records revealed a dural tear rate of 2.87%, damage to the nervous tissue of 1.47%, cauda equina syndrome of 0.75%, neurogenic bowel or bladder of 0.45%, and FBSS of 15.05% following lumbar spine surgery. The incidence of complications was highest for patients undergoing multilevel procedures and posterior fusion. Depression was a significant risk factor for FBSS (risk ratio, 1.74; P<0.0001), damage to nervous tissue (1.41; P<0.0001), and dural tear (1.15; P<0.0001), but had no impact on risk of cauda equina syndrome or neurogenic bowel or bladder. Increased age was associated with higher rates of dural tear and damage to nervous tissue.

CONCLUSIONS

Patients with a history of depression are at significantly increased risk for neurologic complications following lumbar spine surgery and should be managed accordingly.

Dural tear is associated with an increased rate of other perioperative complications in primary lumbar spine surgery for degenerative diseases

Prospective case-control study.This study used a prospective multicenter database to investigate whether dural tear (DT) is associated with an increased rate of other perioperative complications.Few studies have had sufficient data accuracy and statistical power to evaluate the association between DT and other complications owing to a low incidence of occurrence.Between 2012 and 2017, 13,188 patients (7174 men and 6014 women) with degenerative lumbar diseases underwent primary lumbar spine surgery. The average age was 64.8 years for men and 68.7 years for women. DT was defined as a tear that was detected intraoperatively. Other investigated intraoperative surgery-related complications were massive hemorrhage (>2 L of blood loss), nerve injury, screw malposition, cage/graft dislocation, surgery performed at the wrong site, and vascular injury. The examined postoperative surgery-related complications were dural leak, surgical-site infection (SSI), postoperative neurological deficit, postoperative hematoma, wound dehiscence, screw/rod failure, and cage/graft failure. Information related to perioperative systemic complications was also collected for cardiovascular diseases, respiratory diseases, renal and urological diseases, cerebrovascular diseases, postoperative delirium, and sepsis.DTs occurred in 451/13,188 patients (3.4%, the DT group). In the DT group, dural leak was observed in 88 patients. After controlling for the potentially confounding variables of age, sex, primary disease, and type of procedure, the surgery-related complications that were more likely to occur in the DT group than in the non-DT group were SSI (odds ratio [OR] 2.68) and postoperative neurological deficit (OR 3.27). As for perioperative systemic complications, the incidence of postoperative delirium (OR 3.21) was significantly high in the DT group.This study demonstrated that DT was associated with higher incidences of postoperative SSI, postoperative neurological deficit, and postoperative delirium, in addition to directly DT-related dural leak.

Cranial nerve palsies due to incidental durotomy in lumbar Spine surgery: a case report

We present a 65-year old man who underwent a partial laminectomy at L4. During surgery an incidental durotomy (ID) appeared. Postoperatively he developed cranial nerve palsies. Subsequent to surgical closure of the ID, symptoms completely resolved within three months.

Management of Dural Tears in Endoscopic Lumbar Spinal Surgery: A Review of the Literature

OBJECTIVE

The incidental dural tear is a common complication in lumbar spine surgery. It has been reported that the incidence of dural tears is much greater in endoscopic procedures. Primary closure via suturing remains challenging in endoscopic procedures. The objective of this study was to conduct a literature review on the surgical technique for dural closure and repair in endoscopic spine surgery.

METHODS

A systematic literature search was performed using the database PubMed. In total, 12 studies reported specifically about the surgical treatment for dural tear in percutaneous and tubular assisted endoscopic technique. The dural tear rate, the technique of dural closure, postoperative time of bed rest, postoperative symptoms related to cerebrospinal fluid fistula, and revision surgery were assessed.

RESULTS

The overall rate of dural tears in endoscopic spinal surgery was 2.7%, with a range from 0% to 8.6%. The incidence of a dural tear was much greater in cases with lumbar stenosis (3.7%) than in lumbar disc herniation (2.1%). The greatest rate was accompanied by resecting synovial cysts. In addition, the risk of dural tear is greater in bilateral decompression procedures via a unilateral approach. There is no consensus about the ideal technique for dural closure in endoscopic procedures. Furthermore, there is a debate whether dural tear requires surgical treatment or not.

CONCLUSIONS

An autologous muscle or fat graft in combination with fibrin glue or a fibrin-sealed collagen sponge seems to be a good and safe method for the management of dural tear in lumbar endoscopic spine surgery.

Spinal Dural Repair: A Canadian Questionnaire

STUDY DESIGN

Questionnaire.

OBJECTIVES

Iatrogenic dural tear is a complication of spinal surgery with significant morbidity and cost to the health care system. The optimal management is unclear, and therefore we aimed to survey current practices among Canadian practitioners.

METHODS

A questionnaire was administered to members of the Canadian Neurological Surgical Society designed to explore methods of closure of iatrogenic durotomy.

RESULTS

Spinal surgeons were surveyed anonymously with a 55% response rate (n = 91). For pinhole-sized tears, there is no agreement in the methods of closure, with a trend toward sealant fixation (36.7%). Medium- and large-sized tears are predominantly closed with sutures and sealant (67% and 80%, respectively). Anterior tears are managed without primary closure (40.2%), or using sealant alone (48%). Posterior tears are treated with a combination of sutures and sealant (73.8%). Nerve root tears are treated with either sealant alone (50%), or sutures and sealant (37.8%). Tisseal is the preferred sealant (79.7%) over alternatives. With the exception of pin-hole sized tears (39.5%) most respondents recommended bed rest for at least 24 hours in the setting of medium (73.2%) and large (89.1%) dural tears.

CONCLUSIONS

This study elucidates the areas of uncertainty with regard to iatrogenic dural tear management. There is disagreement regarding management of anterior and nerve root tears, pinhole-sized tears in any location of the spine, and whether patients should be admitted to hospital or should be on bed rest following a pinhole-sized dural tear. There is a need for a robust comparative research study of dural repair strategies.

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.

Risk factors for dural tears: a study of elective spine surgery. Neurol Res 2016;39:97-106. [PMID: 27908218 DOI: 10.1080/01616412.2016.1261236]

OBJECTIVE

This study moves beyond previous cohort studies and benchmark data by studying a population of elective spine surgery from a multicenter registry in an effort to validate, disprove, and/or identify novel risk factors for dural tears.

METHODS

A retrospective cohort analysis queried a multicenter registry for patients with degenerative spinal diagnoses undergoing elective spinal surgery from 2010-2014. Multivariable logistic regression analysis interrogated for independent risk factors of dural tears.

RESULTS

Of 104,930 patients, a dural tear requiring repair occurred in 0.6% of cases. On adjusted analysis, the following factors were independently associated with increased likelihood of a dural tear: ankylosing spondylitis vs. intervertebral disc disorders, greater than two levels, combined surgical approach and posterior approach vs. anterior approach, decompression only vs. fusion and decompression, age groups 85+, 75-84 and 65-74 vs. <65, obesity (BMI ≥30), corticosteroid use and preoperative platelet count <150,000.

CONCLUSIONS

This multicenter study identifies novel risk factors for dural tears in the elective spine surgery population, including corticosteroids, thrombocytopenia, and ankylosing spondylitis. The results of this analysis provide further information for surgeons to use both in operative planning and in preoperative counseling when discussing the risk of dural tears.

Postoperative Cerebrospinal Fluid Leak Rates with Subfascial Epidural Drain Placement after Intentional Durotomy in Spine Surgery

Study Design Retrospective chart review. Objective Postoperative cerebrospinal fluid (CSF) leak is a known complication of intraoperative durotomy. Intraoperative placement of subfascial epidural drains following primary dural repair has been proposed as a potential management strategy to prevent formation of CSF cutaneous fistula and symptomatic pseudomeningocele. Here we describe our experience with subfascial drain after intentional durotomy. Methods Medical records of patients who underwent placement of subfascial epidural drains during spinal procedures with intentional intraoperative durotomies over a 4-year period at two institutions were retrospectively reviewed. Primary outcomes of interest were postoperative CSF cutaneous fistula or symptomatic pseudomeningocele formation. Results Twenty-five patients were included. Mean length of follow-up was 9.5 months. Twelve patients (48%) underwent simultaneous arthrodesis. The average duration of the drain was 5.3 days with average daily output of 126.5 mL. Subgroup analyses revealed that average drain duration for the arthrodesis group was 6.33 days, which is significantly greater than that of the nonfused group, which was 3.7 days (p = 0.016). Similarly, the average daily drain output for the arthrodesis subgroup at 153.1 mL was significantly higher than that of the nonfused subgroup (86.8 mL, p = 0.04). No patient developed postoperative CSF cutaneous fistula or symptomatic pseudomeningocele or had negative sequelae associated with overdrainage of CSF. One patient had a delayed wound infection. Conclusions The intraoperative placement of subfascial epidural drains was not associated with postoperative development of CSF cutaneous fistula, symptomatic pseudomeningocele, overdrainage, or subdural hematoma in the cases reviewed. Subfascial closed wound drain placement is a safe and efficacious management method after intentional spinal durotomies. It is particularly helpful in those who undergo simultaneous arthrodesis, as those patients have statistically higher daily drain output and longer drain durations.

Complications of Flat Bed Rest After Incidental Durotomy

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To determine whether bed rest is a risk factor for specific medical complications.

SUMMARY OF BACKGROUND DATA

Flat bed rest after incidental durotomy is commonly used to reduce the risk of CSF leakage and associated complications.

METHODS

Retrospective case series of consecutive patients after lumbar laminectomy were identified. Medical records were reviewed for duration of bed rest and complications (pulmonary, wound, neurological, gastrointestinal, and urinary) in the chart notes, repair methods, subfascial drain placement, consultant notes, imaging reports, and discharge summaries. Patients were compared with duration of bed rest >24 hours versus duration of bed rest ≤24 hours. The incidence of complications was compared between groups using the Fisher exact test.

RESULTS

There were a total of 42 patients with incidental durotomy. There were 18 patients in the bed rest ≤24 hours group and 24 patients in the bed rest >24 hours group. Comparing the bed rest ≤24 hours to bed rest >24 hours patients, there was no statistically significant difference in the incidence of postdurotomy-related neurological complications, wound complications, and need for revision surgery. There was a statistically significant decrease in the incidence of total medical complications in the ≤24-hour group (0% vs. 50%, P=0.0003).

CONCLUSION

There was an increased incidence of medical complications in the bed rest group >24 hours. Flat bed rest after modern dural repair method may not be a necessity in all cases and may be associated with a higher incidence of medical complications.

Repair of Inaccessible Ventral Dural Defect in Thoracic Spine: Double Layered Duraplasty

We propose a double layered (intradural and epidural patch) duraplasty that utilizes Lyoplant and Duraseal. We examined a 47-year-old woman after decompression for thoracic ossification of posterior longitudinal ligament was performed in another hospital. On postoperative day 7, she complained of weakness in both legs. Postoperative magnetic resonance imaging (MRI) showed cerebrospinal fluid (CSF) collection with cord compression. In the operative field, we found 2 large dural defects on the ventral dura mater. We performed a conventional fat graft with fibrin glue. However, the patient exhibited neurologic deterioration, and a postoperative MRI again showed CSF collection. We performed dorsal midline durotomy and inserted a intradural and epidural Lyoplant patch. She immediately experienced diminishing back pain postoperatively. Her visual analog scale and motor power improved markedly. Postoperative MRIs performed at 2 and 16 months showed no spinal cord compression or CSF leakage to the epidural space. We describe a new technique for double layered duraplasty. Although we do not recommend this technique for all dural repairs, double-layered duraplasty may be useful for repairing large inaccessible dural tears in cases of persistent CSF leakage refractory to conventional management.

Management of Incidental Dural Tear During Lumbar Spine Surgery. To Suture or Not to Suture?

OBJECTIVE

Incidental durotomy (ID) during lumbar spine surgery is a frequent complication of growing clinical relevance as the number and complexity of spinal procedures increases. Yet, there is still a lack of guidelines for the treatment of ID with a large heterogeneity of established surgical techniques. The aim of this study was to investigate the efficacy of dural suturing in patients having ID during degenerative lumbar spine surgery, compared with other dural closure techniques.

METHODS

Of 1173 consecutive patients undergoing degenerative lumbar spine surgery from July 2013 to March 2015, in 64 (5.4%) patients 69 (5.8%) IDs occurred. The patients were divided into 3 groups depending on the dural closure technique used: group A, sole dural suture (n = 12, 19%); group B, patch only (TachoSil and/or muscle and/or fat) (n = 22, 32%); group C, dural suture in combination with a patch (n = 34, 49%). The primary end point was revision surgery caused by complications of cerebrospinal fluid leakage after 6 weeks. The secondary end points were operation time and hospitalization time, as well as surgical morbidity.

RESULTS

The 3 groups showed no significant difference in rates of revision surgery (group A: n = 1, 1.4%; group B: n = 4, 5.8%; group C: n = 3; 4.3%; P = 0.5). Furthermore, no significant difference for hospitalization time, operation time, and clinical outcome was found. Extent of ID, American Society of Anesthesiology score, postoperative immobilization, and insertion of a drainage tube were not associated with higher rates of revision surgery. Applying suction once a drainage tube was placed was found to be a significant risk factor for revision surgery (P = 0.003). Furthermore, patients undergoing revision surgery had a significantly higher body mass index (33 kg/m(2) vs. 26.37 kg/m(2); P = 0.006; odds ratio 1.252; P = 0.004).

CONCLUSIONS

Based on our results, the dural closure technique after ID does not seem to influence revision surgery rates due to cerebrospinal fluid leakage and its complications. Further prospective randomized studies are needed to confirm our results.

[Dural tears: Regarding a series of 100 cases]

INTRODUCTION

Dural tears are a dreaded surgical incident because they are difficult to anticipate and may lead to serious complications.

MATERIALS AND METHODS

The French College of Neurosurgery analyzed 100 cases of dural tears declared on the physicians accreditation website from the Haute Autorité de santé (Regional Health Authority). A questionnaire on drainage, type of dural repair and bed rest duration was sent to 87 French neurosurgeons.

RESULTS

Thirty-six percent of patients with dural tears had a history of previous spinal surgery and the most common cause of tear was surgical fibrosis into the operative field for 30% of cases. Sixty-four percent had no history of spinal surgery and, in 33% of cases, the dural tear occurred during a surgery for herniated disc. Drainage was proposed case by case in 76% of cases, the patient was allowed to stand up at day 1 in 48% of cases. The treatment of dural tears combined different techniques including in situ injection of biological glue in 86% of cases. The most common complication was the need of wound repair procedure in 59.5% of cases, which was complicated by meningitis in 21.5% of cases.

CONCLUSION

This study shows the lack of formal consensus about the procedure of repair, the method of drainage or the need to keep the patient bed ridden. This study highlights a relatively high frequency of dural tears, its potentially serious complications and stresses the need for prospective studies in order to define the appropriate action to undertake when faced with this type of incident.

The Incidence and Management of Dural Tears and Cerebrospinal Fluid Leakage during Corrective Osteotomy for Ankylosing Spondylitis with Kyphotic Deformity

OBJECTIVE

To present the incidence and management of dural tears and cerebrospinal fluid leakage during corrective osteotomy [Pedicle Subtraction Osteotomy (PSO) or Smith-Petersen Osteotomy (SPO)] for ankylosing spondylitis with kyphotic deformity.

METHODS

A retrospective study was performed for ankylosing spondylitis patients with fixed sagittal imbalance, who had undergone corrective osteotomy (PSO or SPO) at lumbar level. 87 patients were included in this study. 55 patients underwent PSO, 32 patients underwent SPO. The mean age of the patients at the time of surgery was 41.7 years (21-70 years). Of the 87 patients, 15 patients had intraoperative dural tears.

RESULTS

The overall incidence of dural tears was 17.2%. The incidence of dural tears during PSO was 20.0%, SPO was 12.5%. There was significant difference in the incidence of dural tears based on surgical procedures (PSO vs. SPO) (p<0.05). The dural tears ranged in size from 12 to 221 mm(2). A nine of 15 patients had the relatively small dural tears, underwent direct repair via watertight closure. The remaining 6 patients had the large dural tears, consequently direct repair was impossible. The large dural tears were repaired with an on-lay graft of muscle, fascia or fat harvested from the adjacent operation site. All patients had a successful repair with no patient requiring reoperation for the cerebrospinal fluid leak.

CONCLUSION

The overall incidence of dural tears during PSO or SPO for ankylosing spondylitis with kyphotic deformity was 17.2%. The risk factor of dural tears was complexity of surgery. All dural tears were repaired primarily using direct suture, muscle, fascia or fat graft.

Incidental dural tear in cervical spine surgery: analysis of a nationwide database

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To report the incidence of incidental dural tear (DT) in cervical spine surgery, risk factors, and in-hospital patient outcomes on a national level.

SUMMARY OF BACKGROUND DATA

DT during cervical spine surgery is not as common as that during lumbar spine surgery; however, DT is still a difficult complication.

METHODS

Clinical data were obtained from the US Nationwide Inpatient Sample for 2009. Patients who underwent cervical spine surgery were identified and divided into those with and without DT according to the International Classification of Diseases, 9th revision, Clinical Modification codes. The patient and health care system-related demographic data were retrieved. The incidence of DT and patient outcomes were analyzed. A multivariate logistic regression analysis was performed to identify the risk factors for DT.

RESULTS

The incidence of DT was 0.45% (855/190,021). The multivariate analysis revealed that a diagnosis of myelopathy and ossification of the posterior longitudinal ligament; posterior approach, anterior and posterior approach; and insurance status were the significant risk factors for DT. Comparison between patients with and without DT showed that those with DT had significantly higher overall in-hospital complications (21.6% vs. 7.3%), longer hospital stays (6.0 vs. 3.2 d), a lower proportion who were discharged home routinely (66.3% vs. 83.9%), increased total hospital costs ($96,424 vs. $62,416), and similar in-hospital mortality (0.6% vs. 0.4%).

CONCLUSIONS

The incidence of DT in cervical spine surgery was 0.45% in the United States. The risk of DT was highest with a primary diagnosis of the ossification of the posterior longitudinal ligament (58.4 times). DT significantly increased the rate of in-hospital complications and health care burden.

Obesity is associated with an increased rate of incidental durotomy in lumbar spine surgery

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

To determine the impact of obesity on the rate of incidental durotomy in lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

There is a paucity of data on the overall impact of obesity on the rate of incidental durotomy in lumbar spine surgery, specifically with regard to the type of procedure performed.

METHODS

A large administrative database was queried for all patients who underwent lumbar spine surgery for decompression and/or fusion. They were then stratified into separate cohorts on the basis of body mass index and by procedural codes. Documentation of incidental durotomy was noted. Patient demographics and associated comorbidities were assessed. Odds ratios and 95% confidence intervals were calculated and χ test was used to assess for statistical significance.

RESULTS

The incidental durotomy ranged from 0.5% to 2.6%, with the highest rates observed in multilevel laminectomies and revision decompressions in the obese and morbidly obese groups. For patients who underwent decompression only procedures, nonobese patients had a significantly lower rate of durotomy than the obese and morbidly obese cohorts. For patients who underwent fusion with or without decompression, there was a significantly increased rate of durotomy in obese patients compared with nonobese patients. The morbidly obese cohort also had significantly higher rates of incidental durotomy than the nonobese cohort in both revision decompression and revision fusion procedures.

CONCLUSION

This analysis of a large administrative database demonstrates that obesity is associated with increased rates of incidental durotomy in lumbar spine surgery. Furthermore, obesity, in association with increasing complexity of the procedure, increases the rate of incidental durotomy in lumbar spine surgery. Surgeons must be aware of these increased risks as the rate of obesity increases in the population.

LEVEL OF EVIDENCE

3.

Incidental dural tears during lumbar spine surgery: a retrospective case study of 84 degenerative lumbar spine patients

Study Design

A retrospective case study.

Purpose

To retrospectively review all incidental dural tears (DTs) that occurred at a single institution, classify them anatomically and evaluate the clinical significance of each subgroup.

Overview of Literature

Dural tears are considered the most commonly encountered complication during lumbar spine surgery. In contrast to the high frequency of DTs, reports on the characteristic location and mechanism are sparse.

Methods

We retrospectively retrieved all cases of degenerative lumbar spine surgery performed over a 9-year period and classified all identified DTs according to two independent planes. The coronal plane was divided into lower, middle and upper surgical fields, and the sagittal plane into posterior, lateral and ventral occurring tears. Demographic and clinical variables were retrieved and analyzed to search for significant associations.

Results

From 2003 to 2011, 1,235 cases of degenerative lumbar spine conditions were treated surgically at our institution. In 84 operations (6.8%), an incidental DT was either identified intraoperatively or suspected retrospectively. The most commonly involved location was the lower surgical field (n=39, 46.4%; p=0.002), followed equally by the middle and upper fields (n=16, 19%). In the sagittal plane, the most commonly involved locations were those in close proximity to the nerve root (n=35, 41.6%), followed by the dorsal aspect of the dural sac (n=24, 28.6%). None of the variables recorded was found to be associated with a particular location.

Conclusions

In our series, incidental DTs were found to occur most commonly in the lower surgical field. We hypothesize that local anatomic feature, such as the lordotic and broadening lumbar dura, may play a role in the observed DT tendency to occur in the lower surgical field. In light of the high frequency and potentially substantial resulting morbidity of incidental DTs, a better characterization of its location and mechanism may optimize both prevention and management.

Incidental durotomy in lumbar spine surgery--a three-nation survey to evaluate its management

BACKGROUND

Although it is generally accepted that incidental durotomies (ID) should be primarily repaired, the current literature shows no consensus regarding the peri- and postoperative management in case of ID during lumbar spine surgery. Because ID is a rather frequent complication and may be associated with significant disability, we were interested to analyze the current handling of ID in three European countries.

METHODS

In March 2014, members of the Swiss, German, and Austrian neurosurgical and spine societies were asked to complete an online questionnaire regarding the management of ID during and after lumbar spine surgery. Two, respectively 4 weeks after the first invitation, reminder requests were sent to all invitees, who had not already responded at that time.

RESULTS

There were 175 responses from 397 requests (44.1 %). Responders were predominantly neurosurgeons (89.7 %; 10.3 % were orthopedic surgeons), of which 45.7, 40.0, and 17.8 % work in a non-university hospital, university hospital, and private clinic, respectively. As for the perioperative management of ID, 19.4 % of the responders suggest only bed rest, while, depending on the extent of the ID, 84.0 % suggest additional actions, TachoSil/Spongostan with fibrin glue or a similar product and single suture repair being the most mentioned. Concerning epidural wound drainage in case of ID, 37.2 % desist from placing an epidural wound drainage with or without aspiration, 30.9 % place it sometimes, and 33.7 % place it regularly, but only without aspiration. Most responders prescribe bed rest for 24 (34.9 %) or 48 h (28.0 %), with much fewer prescribing bed rest for 72 h (6.3 %) and none more than 72 h, and 14.9 % of participants never prescribe bed rest. The vast majority of physicians (82.9 %, n = 145) always inform their patients after the operation in case of ID.

CONCLUSIONS

There is substantial heterogeneity in the management of incidental durotomies. The majority of spine surgeons today aim at complete/sufficient primary repair of the ID with varying recommendations concerning postoperative bed rest. Still, there is a trend towards early mobilization if the incidental durotomy has been closed completely/sufficiently with no participant favoring bed rest for more than 72 h.

Do surgeon credentials affect the rate of incidental durotomy during spine surgery

PURPOSE

Incidental durotomy is a potential complication of spinal surgery which can cause a number of intra-operative and post-operative complications. The purpose of this study was to determine if the primary operator's credentials impacted on the incidence of durotomy intra-operatively.

METHODS

Prospectively collected data of operator credentials in relation to the incidence of durotomy were acquired from the International Eurospine Tango database. The significance of variability and risk factors between operators was measured using the Chi-squared test.

RESULTS

Data from a total of 3,764 patients were captured from the Tango registry. Of these 162 (4.3%) had a durotomy. Of the total number of patients, the primary operator was neurosurgical in 1,369 (36.4%) cases; orthopaedic in 180 (4.8%) cases; other (pre-certification) in 236 (6.3%) cases; specialised spine surgeon in 1,741 (46.3%) cases; 6 cases had missing operator data. cerebrospinal fluid (CSF) leak occurred in 57 (4.16%) of neurosurgeon-operated cases; 5 (2.78%) orthopaedic-operated cases; 19 (4.06%) of other surgeon-operated cases; and 81 (4.65%) in specialised spine surgeon-operated cases. Using Chi-squared test, the significance of the variation in incidence of CSF leak between primary operator groups was not statistically significant (P = 0.1405).

CONCLUSION

From the data captured and analysed, the rate of durotomy ranged from 2.78 to 4.65% between operator groups with a mean rate of 4.3%. The primary operator credentials do not appear to significantly impact the rate of durotomy in spine surgery.

Incidental dural tear in spine surgery: analysis of a nationwide database

PURPOSE

The purpose of this study was to report the incidence of dural tear (DT) in spine surgery, risk factors, and patient outcomes on a national level.

METHODS

Clinical data were obtained from the Nationwide Inpatient Sample for 2009. Patients who underwent spine surgery were identified and, among them, patients who had DT were identified, according to the International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) codes. Patient and hospital demographic data were retrieved. The incidence of DT and in-hospital patient outcomes were analyzed. Multivariate logistic regression analysis was performed to identify the risk factors for DT.

RESULTS

The incidence of DT was 2.7 % (17,932/665,818). Multivariate analysis revealed that older age, female gender, increased Elixhauser comorbidity score, and high hospital caseload were the significant risk factors for DT. Comparison between patients with and without DT showed that those with DT had significantly higher overall in-hospital complications (18.8 vs. 10.2 %), higher in-hospital mortality rate (0.4 vs. 0.3 %), longer hospital stays (5.1 vs. 3.7 days), lower proportion discharged home routinely (61.0 vs. 76.8 %), and increased total hospital charges ($85,138 vs. $71,808), respectively.

CONCLUSIONS

The reported incidence of DT in spine surgery was 2.7 % in the US. Risk factors included older age, female gender, increased comorbidities, and high hospital caseload. DT increased the rate of in-hospital complications and mortality and health care burdens.

Incidental dural tear in lumbar spinal decompression and discectomy: analysis of a nationwide database

INTRODUCTION

An incidental dural tear (DT) is one of the most common intraoperative complications in lumbar spine surgery. The purpose of this study was to report the incidence of DT in lumbar spinal decompression (LSD) and lumbar discectomy (LD), risk factors, and patient outcomes on a national level.

MATERIALS AND METHODS

Clinical data were obtained from the Nationwide Inpatient Sample for 2009. Patients who underwent LSD for lumbar spinal stenosis and LD for lumbar disc herniation were identified and divided into those with and without DT, according to the International Classification of Diseases, 9th revision, Clinical Modification codes. Patient and healthcare system-related demographic data were retrieved. The incidence of DT and patient outcomes were analyzed. Multiple logistic regression analysis was performed to identify the risk factors for DT.

RESULTS

The incidence of DT was 6.3 % (4,255/67,982) in LSD and 1.9 % (2,564/136,482) in LD. Multivariate analysis revealed that significant risk factors for DT were hypertension and surgery in a teaching hospital for LSD, and older age and male gender for LD. DT was associated with significantly higher overall in-hospital complications (16.4 vs. 8.6 % for LSD, 9.1 vs. 8.0 % for LD). DT increased in-hospital mortality rate for LSD (0.7 vs. 0.1 %), however, not for LD (0.4 vs. 0.2 %). DT was associated with significantly longer hospital stay for LSD (4.6 vs. 3.0 days), however, not for LD (3.24 vs. 3.16 days). DT significantly increased hospital costs ($52,783 vs. $40,454 for LSD, and $32,307 vs. $27,787 for LD).

CONCLUSIONS

The incidence of DT was higher in LSD (6.3 %) than in LD (1.9 %), based on a national database. The effect of DT on in-hospital morbidity and mortality and health care burdens was more significant in LSD than in LD.

Common surgical complications in degenerative spinal surgery

The rapid growth of spine degenerative surgery has led to unrelenting efforts to define and prevent possible complications, the incidence of which is probably higher than that reported and varies according to the region of the spine involved (cervical and thoracolumbar) and the severity of the surgery. Several issues are becoming progressively clearer, such as complication rates in primary versus revision spinal surgery, complications in the elderly, the contribution of minimally invasive surgery to the reduction of complication rate. In this paper the most common surgical complications in degenerative spinal surgery are outlined and discussed.

Incidental durotomy during lumbar spine surgery: risk factors and anatomic locations

Object

Incidental durotomy (dural tear) is a common complication of lumbar spine surgery. The purpose of this study was to clarify the anatomical location of and the specific causative factors for incidental durotomy during primary lumbar spine surgery.

Methods

The authors retrospectively reviewed 1014 consecutive cases involving patients (412 women and 602 men; mean age 57 years; age range 11–97 years) who underwent a surgical procedure for treatment of degenerative lumbar spinal disease at their institution between 2002 and 2008. In total, 1261 disc levels were treated surgically. Disease at the treated levels included 544 disc herniations, 453 instances of spinal canal stenosis without spondylolisthesis, 188 instances of lumbar spinal canal stenosis with spondylolisthesis (degenerative spondylolisthesis), 49 instances of combined stenosis (stenosis with disc herniation), and 22 juxtafacet cysts. In 5 of the treated levels, the condition was classified as “other” disease. Treatment included fenestration with discectomy in 547 levels, fenestration alone in 626, fenestration with resection of juxtafacet cysts in 22, unilateral recapping laminoplasty in 20, posterolateral spinal fusion or posterior lumbar interbody fusion in 17, microscopic discectomy with tubular retractor in 14, and “other” in 15.

Results

Unintended durotomy occurred in 4% of cases and in 3.3% of disc levels. The incidence of dural tear was significantly higher in women (5.6%) than in men (3%). The incidence of dural tear was 2% in disc levels with lumbar disc herniation, 1.8% with lumbar spinal canal stenosis without spondylolisthesis, 9% with degenerative spondylolisthesis, and 18.2% with juxtafacet cysts; the incidence was significantly higher in levels with degenerative spondylolisthesis or levels with juxtafacet cysts, than in those with other diseases. Incidental durotomy occurred in 4 critical anatomical zones, namely, the caudal margin of the cranial lamina, cranial margin of the caudal lamina, herniated disc level, and medial aspect of the facet joint adjacent to the insertion of the hypertrophic ligamentum flavum.

Conclusions

Risk factors for unintended durotomy were female sex, older age, degenerative spondylolisthesis, and juxtafacet cysts. In this study, the authors identified 4 high-risk anatomical zones that spine surgeons should be aware of to avoid dural tears.