Dural Tears in Adult Deformity Surgery: Incidence, Risk Factors, and Outcomes

High incidence of dural tears with 3-column osteotomies: a systematic review of adult spinal deformity surgery literature for the past decade

PURPOSE

Dural tear (DT) is a well-known complication of spinal surgery. We aimed to systematically review the literature from the past decade and determine the incidence and risk factors for DT in the adult spinal deformity (ASD) population to improve both the surgical strategy and counseling of patients undergoing ASD correction.

METHODS

A systematic review from 2013 to 2023 utilizing PRISMA guidelines was performed. The MEDLINE database was used to collect primary English language articles. The inclusion criterion for patients was degenerative ASD. Pediatric studies, animal studies, review articles, case reports, studies investigating minimally invasive surgery (MIS), studies lacking data on DT incidence, and articles pertaining to infectious, metastatic or neoplastic, traumatic, or posttraumatic etiologies of ASD were excluded.

RESULTS

Our results demonstrate that the incidence of DT in ASD surgery ranges from 2.0% to 35.7%, which is a much broader range than the reported incidence for non deformity surgery. Moreover, the average rate of DT during ASD surgery stratified by surgical technique was greater for osteotomy overall (19.5% +/- 7.9%), especially for 3-column osteotomy (3CO), and lower for interbody fusion (14.3% +/- 9.9%). Risk factors for DT in the ASD surgery cohort included older age, revision surgery, chronic severe compression, higher-grade osteotomy, complexity of surgery, rheumatoid arthritis (RA), and higher Anesthesiology Society of America (ASA) grade.

CONCLUSION

To our knowledge, this is the first systematic review discussing the incidence of and risk factors for DT in the ASD population. We found that the risk factors for DT in ASD patients were older age, revision surgery, chronic severe compression, a greater degree of osteotomy, complexity of surgery, RA, and a higher ASA grade. These findings will help guide spine surgeons in patient counseling as well as surgical planning.

Incidental Durotomy Repair in Lumbar Spine Surgery: Institutional Experience and Review of Literature

STUDY DESIGN

: Retrospective Chart Review.

OBJECTIVES

Incidental durotomies (IDs) are common spine surgery complications. In this study, we present a review on the most commonly utilized management strategies, report our institutional experience with case examples, and describe a stepwise management algorithm.

METHODS

A retrospective review was performed of the electronic medical records of all patients who underwent a thoracolumbar or lumbar spine surgery between March 2017 and September 2019. Additionally, a literature review of the current management approaches to treat IDs and persistent postoperative CSF leaks following lumbar spine surgeries was performed.

RESULTS

We looked at 1133 patients that underwent posterior thoracolumbar spine surgery. There was intraoperative evidence of ID in 116 cases. Based on our cohort and the current literature, we developed a progressive treatment algorithm for IDs that begins with a primary repair, which can be bolstered by dural sealants or a muscle patch. If this fails, the primary repair can be followed by a paraspinal muscle flap, as well as a lumbar drain. If the patient cannot be weaned from temporary CSF diversion, the final step in controlling postoperative leak is longterm CSF diversion via a lumboperitoneal shunt. In our experience, these shunts can be weaned once the patient has no further clinical or radiographic signs of CSF leak.

CONCLUSIONS

There is no standardized management approach of IDs and CSF leaks in the literature. This article intends to provide a progressive treatment algorithm and contribute to the development process of a treatment consensus.

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.

The Predictors of Incidental Durotomy in Patients Undergoing Pedicle Subtraction Osteotomy for the Correction of Adult Spinal Deformity

Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann-Whitney U tests, Chi-squared analyses, and Fisher's exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.

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.

Complications and Revisions After Spine Surgery in Patients With Skeletal Dysplasia: Have We Improved?

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To report contemporary rates of complications and subsequent surgery after spinal surgery in patients with skeletal dysplasia.

METHODS

A case series of 25 consecutive patients who underwent spinal surgery between 2007 and 2017 were identified from a single institution's skeletal dysplasia registry. Patient demographics, medical history, surgical indication, complications, and subsequent surgeries (revisions, extension to adjacent levels, or for pathology at a non-contiguous level) were collected. Charlson comorbidity indices were calculated as a composite measure of overall health.

RESULTS

Achondroplasia was the most common skeletal dysplasia (76%) followed by spondyloepiphyseal dysplasia (20%); 1 patient had diastrophic dysplasia (4%). Average patient age was 53.2 ± 14.7 years and most patients were in excellent cardiovascular health (88% Charlson Comorbidity Index 0-4). Mean follow up after the index procedure was 57.4 ± 39.2 months (range). Indications for surgery were mostly for neurologic symptoms. The most commonly performed surgery was a multilevel thoracolumbar decompression without fusion (57%). Complications included durotomy (36%), neurologic complication (12%), and infection requiring irrigation and debridement (8%). Nine patients (36%) underwent a subsequent surgery. Three patients (12%) underwent a procedure at a non-contiguous anatomic zone, 3 (12%) underwent a revision of the previous surgery, and another 3 (12%) required extension of their previous decompression or fusion.

CONCLUSIONS

Surgical complication rates remain high after spine surgery in patients with skeletal dysplasia, likely attributable to inherent characteristics of the disease. Patients should be counseled on their risk for complication and subsequent surgery.

Can We Geographically Validate a Natural Language Processing Algorithm for Automated Detection of Incidental Durotomy Across Three Independent Cohorts From Two Continents?

BACKGROUND

Incidental durotomy is an intraoperative complication in spine surgery that can lead to postoperative complications, increased length of stay, and higher healthcare costs. Natural language processing (NLP) is an artificial intelligence method that assists in understanding free-text notes that may be useful in the automated surveillance of adverse events in orthopaedic surgery. A previously developed NLP algorithm is highly accurate in the detection of incidental durotomy on internal validation and external validation in an independent cohort from the same country. External validation in a cohort with linguistic differences is required to assess the transportability of the developed algorithm, referred to geographical validation. Ideally, the performance of a prediction model, the NLP algorithm, is constant across geographic regions to ensure reproducibility and model validity.

QUESTION/PURPOSE

Can we geographically validate an NLP algorithm for the automated detection of incidental durotomy across three independent cohorts from two continents?

METHODS

Patients 18 years or older undergoing a primary procedure of (thoraco)lumbar spine surgery were included. In Massachusetts, between January 2000 and June 2018, 1000 patients were included from two academic and three community medical centers. In Maryland, between July 2016 and November 2018, 1279 patients were included from one academic center, and in Australia, between January 2010 and December 2019, 944 patients were included from one academic center. The authors retrospectively studied the free-text operative notes of included patients for the primary outcome that was defined as intraoperative durotomy. Incidental durotomy occurred in 9% (93 of 1000), 8% (108 of 1279), and 6% (58 of 944) of the patients, respectively, in the Massachusetts, Maryland, and Australia cohorts. No missing reports were observed. Three datasets (Massachusetts, Australian, and combined Massachusetts and Australian) were divided into training and holdout test sets in an 80:20 ratio. An extreme gradient boosting (an efficient and flexible tree-based algorithm) NLP algorithm was individually trained on each training set, and the performance of the three NLP algorithms (respectively American, Australian, and combined) was assessed by discrimination via area under the receiver operating characteristic curves (AUC-ROC; this measures the model's ability to distinguish patients who obtained the outcomes from those who did not), calibration metrics (which plot the predicted and the observed probabilities) and Brier score (a composite of discrimination and calibration). In addition, the sensitivity (true positives, recall), specificity (true negatives), positive predictive value (also known as precision), negative predictive value, F1-score (composite of precision and recall), positive likelihood ratio, and negative likelihood ratio were calculated.

RESULTS

The combined NLP algorithm (the combined Massachusetts and Australian data) achieved excellent performance on independent testing data from Australia (AUC-ROC 0.97 [95% confidence interval 0.87 to 0.99]), Massachusetts (AUC-ROC 0.99 [95% CI 0.80 to 0.99]) and Maryland (AUC-ROC 0.95 [95% CI 0.93 to 0.97]). The NLP developed based on the Massachusetts cohort had excellent performance in the Maryland cohort (AUC-ROC 0.97 [95% CI 0.95 to 0.99]) but worse performance in the Australian cohort (AUC-ROC 0.74 [95% CI 0.70 to 0.77]).

CONCLUSION

We demonstrated the clinical utility and reproducibility of an NLP algorithm with combined datasets retaining excellent performance in individual countries relative to algorithms developed in the same country alone for detection of incidental durotomy. Further multi-institutional, international collaborations can facilitate the creation of universal NLP algorithms that improve the quality and safety of orthopaedic surgery globally. The combined NLP algorithm has been incorporated into a freely accessible web application that can be found at https://sorg-apps.shinyapps.io/nlp_incidental_durotomy/ . Clinicians and researchers can use the tool to help incorporate the model in evaluating spine registries or quality and safety departments to automate detection of incidental durotomy and optimize prevention efforts.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Iliac Screw Fixation Revisited: Improved Clinical and Radiologic Outcomes Using a Modified Iliac Screw Fixation Technique

STUDY DESIGN

A retrospective study.

OBJECTIVE

To describe the modified iliac screw (mILS) technique and compare it to other spinopelvic fixation techniques in terms of wound healing complications, hardware prominence, and failure.

SUMMARY OF BACKGROUND DATA

The traditional entry point of an iliac screw often causes postoperative gluteal pain from the prominent screw head. The use of an offset connector also adds a point of weakness to the construct. By choosing a different screw entry point offset connectors can be avoided, and the screw head itself is less prominent, thereby reducing postoperative discomfort.

MATERIALS AND METHODS

A retrospective analysis was performed of adult patients undergoing lumbopelvic fixation (LPF) between January 2014 and June 2019. Patients were grouped into 1 of 3 groups based on the technique of pelvic fixation: S2 alar-iliac (S2AI) screw, traditional iliac screw (tILS), and mILS. The primary outcome parameter was the minimal distance from screw head to skin. Secondary outcome parameters were instrumentation loosening/failure, adjacent level fractures, pseudoarthrosis, and medial or lateral iliac screw perforation.

RESULTS

A total of 190 patients undergoing LPF were included in the following 3 groups: mILS group (n=113), tILS group (n=40), and S2AI group (n=37). The mean minimal distance from screw head to skin in the mILS group was 31.3 mm compared with 23.7 mm in the tILS group (P<0.00199). No statistically significant differences were found when comparing the 3 groups with respect to complications. The mILS group did not show any cases of prominent instrumentation and had the lowest rate of instrumentation failure.

CONCLUSIONS

The mILS technique is an acceptable alternative for LPF, offering the benefits of iliac screw fixation while avoiding offset connectors and screw prominence complications associated with tILS.

LEVEL OF EVIDENCE

Level III.

Risk Factors for Accidental Dural Tears in Spinal Surgery

BACKGROUND

Accidental dural tears (DTs) are familiar complications of spinal surgery. Their reported incidence varies widely, and several risk factors have been proposed in the literature. The aim of this study was to conduct a systematic review and meta-analysis to determine the rate of DTs and assess their associated risk factors.

METHODS

A systematic literature search was conducted using specific MeSH and Text terms. Only articles with prospective data reporting the incidence and risk factors were selected and reviewed based on specific inclusion and exclusion criteria.

RESULTS

Twenty-three studies were included. The reported incidence rate ranged from 0.4% to 15.8%, giving an overall pooled incidence rate of 5.8% (95% confidence interval [CI] 4.4-7.3). The incidence rate varied in relation to the part of the spine and the type of surgery. Three factors were associated with a high rate of DTs: age (overall mean difference of 3.04, 95% CI 2.49-3.60), revision surgery (overall odds ratio of 2.28, 95% CI 1.84-2.83), and lumbar stenosis (overall odds ratio of 2.03, 95% CI 1.50-2.75). Diabetes was weakly associated with DTs, with an odds ratio of 1.40 (95% CI 1.01-1.93). The overall effects of sex and obesity were not statistically significant.

CONCLUSION

Advancing age, revision surgery, and lumbar stenosis were significantly associated with increased risk of DTs. These factors should be taken into consideration during the consenting process for spinal surgery.

CLINICAL RELEVANCE

Risk of dural tear during spine surgery.

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

STUDY DESIGN

Systemic review and meta-analysis.

OBJECTIVES

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

METHOD

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

RESULTS

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

CONCLUSION

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

Incidental durotomy: predictive risk model and external validation of natural language process identification algorithm

OBJECTIVE

Incidental durotomy is a common complication of elective lumbar spine surgery seen in up to 11% of cases. Prior studies have suggested patient age and body habitus along with a history of prior surgery as being associated with an increased risk of dural tear. To date, no calculator has been developed for quantifying risk. Here, the authors' aim was to identify independent predictors of incidental durotomy, present a novel predictive calculator, and externally validate a novel method to identify incidental durotomies using natural language processing (NLP).

METHODS

The authors retrospectively reviewed all patients who underwent elective lumbar spine procedures at a tertiary academic hospital for degenerative pathologies between July 2016 and November 2018. Data were collected regarding surgical details, patient demographic information, and patient medical comorbidities. The primary outcome was incidental durotomy, which was identified both through manual extraction and the NLP algorithm. Multivariable logistic regression was used to identify independent predictors of incidental durotomy. Bootstrapping was then employed to estimate optimism in the model, which was corrected for; this model was converted to a calculator and deployed online.

RESULTS

Of the 1279 elective lumbar surgery patients included in this study, incidental durotomy occurred in 108 (8.4%). Risk factors for incidental durotomy on multivariable logistic regression were increased surgical duration, older age, revision versus index surgery, and case starts after 4 pm. This model had an area under curve (AUC) of 0.73 in predicting incidental durotomies. The previously established NLP method was used to identify cases of incidental durotomy, of which it demonstrated excellent discrimination (AUC 0.97).

CONCLUSIONS

Using multivariable analysis, the authors found that increased surgical duration, older patient age, cases started after 4 pm, and a history of prior spine surgery are all independent positive predictors of incidental durotomy in patients undergoing elective lumbar surgery. Additionally, the authors put forth the first version of a clinical calculator for durotomy risk that could be used prospectively by spine surgeons when counseling patients about their surgical risk. Lastly, the authors presented an external validation of an NLP algorithm used to identify incidental durotomies through the review of free-text operative notes. The authors believe that these tools can aid clinicians and researchers in their efforts to prevent this costly complication in spine surgery.

Complications of Thoracolumbar Adult Spinal Deformity Surgery

Adult spinal deformity (ASD) is a challenging problem for spine surgeons given the high risk of complications, both medical and surgical. Surgeons should have a high index of suspicion for medical complications, including cardiac, pulmonary, thromboembolic, genitourinary and gastrointestinal, renal, cognitive and psychiatric, and skin conditions, in the perioperative period and have a low threshold for involving specialists. Surgical complications, including neurologic injuries, vascular injuries, proximal junctional kyphosis, durotomy, and pseudarthrosis and rod fracture, can be devastating for the patient and costly to the health-care system. Mortality rates have been reported to be between 1.0% and 3.5% following ASD surgery. With the increasing rate of ASD surgery, surgeons should properly counsel patients about these risks and have a high index of suspicion for complications in the perioperative period.

Dural Tears in Percutaneous Biportal Endoscopic Spine Surgery: Anatomical Location and Management

OBJECTIVE

To determine the rate and anatomical location of dural tears associated with spinal surgery using a percutaneous biportal endoscopic surgery (PBES) technique. We investigated the relationship between dural tears and the type of procedure and type of instrument used.

METHODS

We retrospectively analyzed 643 PBES cases by reviewing the medical records, operative records, and operative videos. Incidental durotomy was identified in 29 cases. We analyzed the size and anatomical location of the dural tears, the surgical instrument that caused the tear, and the technique used to seal the tear.

RESULTS

The dural tear incidence was 4.5% (29 of 643 cases). Tears in the exiting nerve area (2 cases; 6.9%) had mainly been caused by curettage, tears in the thecal sac area (18 cases; 62.1%) were associated with electric drill and forceps use; and tears in the traversing nerve area were associated with the use of a Kerrison punch (9 cases; 31%). Of the 29 cases of dural tear, 12 were treated with in-hospital monitoring and bed rest, 14 were treated with a fibrin sealant, 2 were treated with a nonpenetrating titanium clip, and 1 was converted to microscopic surgery. One case of postoperative meningocele after conservative treatment required endoscopic revision surgery to close the dural tear.

CONCLUSIONS

Most cases of incidental dural tear during PBES were treated with an endoscopic procedure. The incidence of dural tear was no greater than that associated with microscopic surgery. Our management strategy for incidental dural tears during PBES has been shown to be safe and effective.

Surgical Risk Assessment and Prevention in Elderly Spinal Deformity Patients

Introduction:

Prevalence of adult deformity surgery in the elderly individuals continues to increase. These patients have additional considerations for the spine surgeon during surgical planning. We perform an informative review of the spinal and geriatric literature to assess preoperative and intraoperative factors that impact surgical complication occurrences in this population.

Significance:

There is a need to understand surgical risk assessment and prevention in geriatric patients who undergo thoracolumbar adult deformity surgery in order to prevent complications.

Methods:

Searches of relevant biomedical databases were conducted by a medical librarian. Databases searched included MEDLINE, Web of Science, CINAHL, IPA, Cochrane, PQ Health and Medical, SocINDEX, and WHO’s Global Health Library. Search strategies utilized Medical Subject Headings plus text words for extensive coverage of scoliosis and surgical technique concepts.

Results:

Degenerative scoliosis affects 68% of the geriatric population, and the rate of surgical interventions for this pathology continues to increase. Complications following spinal deformity surgery in this patient population range from 37% to 62%. Factors that impact outcomes include age, comorbidities, blood loss, and bone quality. Using these data, we summarize multimodal risk prevention strategies that can be easily implemented by spine surgeons.

Conclusions:

After evaluation of the latest literature on the complications associated with adult deformity surgery in geriatric patients, comprehensive perioperative management is necessary for improved outcomes. Preoperative strategies include assessing physiological age via frailty score, nutritional status, bone quality, dementia/delirium risk, and social activity support. Intraoperative strategies include methods to reduce blood loss and procedural time. Postoperatively, development of a multidisciplinary team approach that encourages early ambulation, decreases opiate use, and ensures supportive discharge planning is imperative for better outcomes for this patient population.