The True Cost of a Dural Tear: Medical and Economic Ramifications of Incidental Durotomy During Lumbar Discectomy in Elderly Medicare Beneficiaries

Incidental durotomy in lumbar decompressive surgery: incidence and risk-factors, and the effect of durotomy on hospital and patient metrics

PURPOSE

To evaluate incidental lumbar durotomy incidence and risk-factors, and the association of durotomy with perioperative metrics and patient-reported outcomes.

METHODS

A total 3140 cases of 1-3 level elective decompressive surgery from 2008 to 2023 at a single centre were included. Multivariable analysis was performed on literature derived variables to identify independent risk-factors for durotomy. Absolute difference or absolute risk increase (ARI) between durotomy and non-durotomy perioperative metrics was calculated. The association between durotomy and 3-month or 12-month patient-reported outcome measures was assessed.

RESULTS

All-procedure durotomy incidence was 4.5% (142/3140). Durotomy risk-factors were age (odds ratio (OR) 1.016, 95% confidence intervals (95% CI) 1.011-1.020), female (OR 1.48, 95% CI 1.26-1.74), number of operative levels (two-level OR 1.81, 95% CI 1.48-2.21; three-level OR 3.18, 95% CI 2.14-4.72), multiple versus no previous operation (OR 1.85, 95% CI 1.11-3.07), and fusion with discectomy versus discectomy (OR 2.36, 95% CI 1.90-2.93). Durotomy was associated with longer length of stay (∆2.4 days, p < 0.001), longer operative time (∆21 min, p < 0.001), and higher rate of iatrogenic nerve injury (ARI 4.3%, p < 0.001), 30-day return to theatre (ARI 5.7%, p < 0.001), and 30-day readmission (ARI 4.4%, p = 0.002). Durotomy was not associated with poorer patient-reported outcomes.

CONCLUSION

Dural tears are often under-reported and are associated with longer hospital stay, increased operative time, and rare perioperative complications which increase healthcare costs. Dural tears did not, however, detrimentally affect patient-reported disability or pain outcomes.

The Rochester Model for Spinal CSF Leak Repair Simulation and Scoring

BACKGROUND AND OBJECTIVE

Iatrogenic spinal durotomies occur at a rate of 1% to 17%. Surgical simulation for durotomy repair is needed to provide affordable, accessible, and validated practice. This study sought to design and validate a simple 3-dimensional printed model for spinal cerebrospinal fluid (CSF) leak repair and to introduce the Rochester original objective structured assessment of technical skills (OSATS) CSF leak (ROCL) repair criteria for assessment.

METHODS

A spinal model was designed to mimic a lumbar laminectomy with the L3-5 lamina removed and 3-dimensional printed using Vero polymers. The model was paired with a porcine collagen "dura" that was pressurized using IV saline and overlayed with gel-molded fascial, muscle, and skin layers with an opening. Participants were provided a training model with a 1.5-cm midline durotomy, surgical microinstrument set, microscope, and 6-0 prolene suture. The 25-point ROCL repair criteria were adapted from the original OSATS principles to assess proficiency in surgical repair by 2 blinded neurosurgeons not participating in the trials. Postsimulation survey data regarding model realism were collected.

RESULTS

Six residents and 4 attendings participated. Median operative time in minutes was 13 minutes among residents and 7 minutes among attendings. Moreover, the ROCL score was a median of 19/25 for attendings and 15/25 for residents. The suture angle was statistically more consistent among senior residents and attendings compared with junior residents. Participants agreed that the model was realistic (median 4/5), useful for improving the operative technique (median 5/5), and would increase comfort in spinal CSF leak repair procedures (median 5/5). Each reusable model had a cost of $19.99 if printed with polylactic acid and each replacement dura cost <3¢.

CONCLUSION

This study presents an affordable, realistic, and educational spinal CSF leak repair model and introduces ROCL for assessment.

Economic Implications of Dural Tears in Lumbar Microdiscectomies: A Retrospective, Observational Study

OBJECTIVE

Dural tears (DTs) are a frequent complication after lumbar spine surgery. We sought to determine the incidence of DTs and the related impact on health care expenditures after lumbar discectomies.

METHODS

In this retrospective cohort study, all patients with first-time single-level lumbar discectomies at our institution who underwent minimally invasive surgery from 2015 to 2019 were reviewed. Age, sex, weight, height, body mass index, costs, revenues, length of stay, American Society of Anesthesiologists score, Charlson Comorbidity Index, and operative time (OT) were assessed. Exclusion criteria were age <18 years, previous spine surgery, multiple or traumatic disc herniations, and malignant and infectious diseases.

RESULTS

The follow-up time was at least 12 months postoperatively. Of 358 patients identified with lumbar discectomies, 230 met the inclusion criteria. Incidence of DTs was 3.5%. Mean costs (P < 0.001), economic loss (P < 0.01), and OT (P < 0.0001) were found to be significantly higher in the DT group compared with the control group of patients without a DT. The revenues were not statistically different between the 2 groups (P > 0.05). Further analysis of the control group by profit and loss revealed significantly higher body mass index (P < 0.05), length of stay (P < 0.0001), and OT (P < 0.0001) in the loss group.

CONCLUSIONS

DTs represent a significant socioeconomic burden in lumbar spine surgery and cause severe secondary complications. The impact of DTs on health care expenses is primarily based on significantly higher OT and a higher mean length of stay.

Early ambulation versus prolonged bed rest for incidental durotomies in spine procedures: a systematic review and meta-analysis

Incidental durotomies are frequent complications of spine surgery associated with cerebrospinal fluid (CSF) leak-related symptoms. Management typically involves prolonged bed rest to reduce CSF pressure at the durotomy site. However, early ambulation may be a safer, effective alternative. PubMed, Web of Science, Embase, Cochrane, and Scopus were systematically searched for studies comparing early ambulation (bed rest ≤ 24 h) with prolonged bed rest (> 24 h) for patients with incidental durotomies in spine surgeries. The outcomes of interest were CSF leak, hypotensive headache, additional surgical repair, pseudomeningocele, and pulmonary complications. Systematic reviews and meta-analysis were performed following the Cochrane Handbook for Systematic Reviews of Interventions. We included a total of 704 patients from 6 studies. There was a significant reduction in the incidence of pulmonary complications (RR 0.23; 95% CI 0.08-0.67; p = 0.007) in the early mobilization group. The incidence of CSF leak (RR 1.34; 95% CI 0.83-2.14; p = 0.23), hypotensive headache (RR 0.72; 95% CI 0.27-1.90; p = 0.50), additional repair surgery (RR 1.29; 95% CI 0.76-2.2; p = 0.35), and pseudomeningocele (RR 1.29; 95% CI 0.20-8.48; p = 0.79) did not differ significantly. In patients with incidental durotomy following spinal surgery, early mobilization was associated with a lower incidence of pulmonary complications as compared with prolonged bed rest. There was no significant difference between groups in terms of CSF leak, need for additional repair, pseudomeningocele, and hypotensive headache.

Local contamination is a major cause of early deep wound infections following open posterior lumbosacral fusions

PURPOSE

Postoperative surgical site infection in patients treated with lumbosacral fusion has usually been thought to be caused by perioperative contamination. With the proximity of these incisions to the perineum, this study sought to determine if contamination by gastrointestinal and/or urogenital flora should be considered as a major cause of this complication.

METHODS

We conducted a retrospective review of adults treated with open posterior lumbosacral fusions between 2014 and 2021 to identify common factors in deep postoperative infection and the nature of the infecting organisms. Cases of tumor, primary infection and minimally invasive surgery were excluded.

RESULTS

489 eligible patients were identified, 20 of which required debridement deep to the fascia (4.1%). Mean age, operative time, estimated blood loss and levels fused were similar between both groups. The infected group had a significantly higher BMI. The mean time from primary procedure to debridement was 40.8 days. Four patients showed no growth, 3 showed Staphylococcus sp. infection (Perioperative Inside-Out) requiring debridement at 63.5 days. Thirteen showed infection with intestinal or urogenital pathogens (Postoperative Outside-In) requiring debridement at 20.0 days. Postoperative Outside-In infections led to debridement 80.3 days earlier than Perioperative Inside-Out infections (p = 0.007).

CONCLUSIONS

65% of deep infections in patients undergoing open lumbosacral fusion were due to early contamination by pathogens associated with the gastrointestinal and/or urogenital tracts. These required earlier debridement than Staphylococcus sp.

INFECTIONS

There should be renewed focus on keeping these pathogens away from the incision during the early stages of wound healing.

Complications after early versus late mobilization after an incidental durotomy: a systematic review and meta-analysis

BACKGROUND

An incidental durotomy (IDT) is a frequent complication of spinal surgery. The conventional management involving a period of flat bed rest is highly debatable. Indeed, there are scanty data and no consensus regarding the need or ideal duration of post-operative bed rest following IDT.

OBJECTIVE

To systematically evaluate the literature regarding the outcomes of mobilization within 24 h and after 24 h following IDT in open lumbar or thoracic surgery with respect to the length of hospital stay, minor and major complications.

METHODS

A systematic review of the literature using PubMed, Embase and Cochrane and dating up until September 2022 was undertaken following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Quality of evidence was assessed using a modified version of Sackett's Criteria of Evidence Support.

RESULTS

Out of 532 articles, 6 studies met the inclusion criteria (1 Level-I, 4 level-III and 1 Level-IV evidence) and were analyzed. Overall, 398 patients of mean age 59.9 years were mobilized within 24 h. The average length of stay (LOS) for this group was 5.7 days. Thirty-four patients (8.5%) required reoperation while the rate of minor complications was 25.4%. Additionally, 265 patients of mean age 63 years with IDT were mobilized after 24 h. The average LOS was 7.8 days. Twenty patients (7.54%) required reoperation while the rate of minor complications was 55%. Meta-analysis comparing early to late mobilization, showed a significant reduction in the risk of minor complications and shorter overall LOS due to early mobilization, but no significant difference in major complications and reoperation rates.

CONCLUSIONS

Although early mobilization after repaired incidental dural tears in open lumbar and thoracic spinal surgery has a similar major complication/ reoperation rates compared to late mobilization, it significantly decreases the risk of minor complications and length of hospitalization.

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.

Early mobilization versus bed rest for incidental durotomy: an institutional cohort study

OBJECTIVE

The aim of this study was to assess whether flat bed rest for > 24 hours after an incidental durotomy improves patient outcome or is a risk factor for medical and wound complications and longer hospital stay.

METHODS

Medical records of consecutive patients undergoing thoracic and lumbar decompression procedures from 2010 to 2020 were reviewed. Operative notes and progress notes were reviewed and searched to identify patients in whom incidental durotomies occurred. The need for revision surgery related to CSF leak or wound infection was recorded. The duration of bed rest, length of hospital stay, and complications (pulmonary, gastrointestinal, urinary, and wound) were recorded. The rates of complications were compared with regard to the duration of bed rest (≤ 24 hours vs > 24 hours).

RESULTS

A total of 420 incidental durotomies were identified, indicating a rate of 6.7% in the patient population. Of the 420 patients, 361 underwent primary repair of the dura; 254 patients were prescribed bed rest ≤ 24 hours, and 107 patients were prescribed bed rest > 24 hours. There was no statistically significant difference in the need for revision surgery (7.87% vs 8.41%, p = 0.86) between the two groups, but wound complications were increased in the prolonged bed rest group (8.66% vs 15.89%, p = 0.043). The average length of stay for patients with bed rest ≤ 24 hours was 4.47 ± 3.64 days versus 7.24 ± 4.23 days for patients with bed rest > 24 hours (p < 0.0001). There was a statistically significant increase in the frequency of ileus, urinary retention, urinary tract infections, pulmonary issues, and altered mental status in the group with prolonged bed rest after an incidental durotomy. The relative risk of complications in the group with bed rest ≤ 24 hours was 50% less than the group with > 24 hours of bed rest (RR 0.5, 95% CI 0.39-0.62; p < 0.0001).

CONCLUSIONS

In this retrospective study, the rate of revision surgery was not higher in patients with durotomy who underwent immediate mobilization, and medical complications were significantly decreased. Flat bed rest > 24 hours following incidental durotomy was associated with increased length of stay and increased rate of medical complications. After primary repair of an incidental durotomy, flat bed rest may not be necessary and appears to be associated with higher costs and complications.

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.

Economic Analysis of Transforaminal Lumbar Interbody Fusion Surgery Utilizing a Curved Bone Removal Device

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF) represents a commonly performed spinal procedure that poses a significant financial burden on patients, hospitals and insurers. Reducing these costs, while maintaining efficacy, may be assisted by a new powered endplate preparation device, designed to shorten procedural time while offering positive impacts on other elements that contribute to the cost of care.

OBJECTIVE

The aim of the study was to assess and compare the individual cost elements of TLIF procedures with and without the use of the device, to determine whether application of this technology translated into any material procedural savings.

METHODS

The records of 208 single-level TLIF procedures in a single hospital were reviewed. Surgical time, length of hospital stay, blood loss, infection rate, and other parameters were compared for the cases where the device was used (device group; n = 143) and cases which used standard tools (control group; n = 65). The cost per unit of each element was derived from the literature, online resources, and the hospital's financial department.

RESULTS

The analysis revealed a shorter surgery duration in the device group (23 min, after controlling for procedure year and patient characteristics; statistically significant at p < 0.001) and lower complication and readmission rates (p = 0.67 and p = 0.21, respectively) associated with the use of the device, leading to a statistically significant cost reduction of approximately 2060 US dollars (US$) (p < 0.01).

CONCLUSION

The study suggests that use of the device may lead to a cost reduction and shorter procedure without deteriorating the clinical outcome.

Incidental Durotomy in Lumbar Spine Surgery; Risk Factors, Complications, and Perioperative Management

Incidental durotomy (ID) can occur in up to 14% of all lumbar spine surgeries. The risk of this complication is markedly higher among elderly patients with advanced spinal pathology. In addition, revision cases and other more invasive procedures increase the risk of ID. When unrepaired, IDs can increase the risk of developing meningitis and can lead to the formation of cerebrospinal fluid fistulas and pseudomeningoceles. Intraoperative recognition and repair are essential to ID management, although repair techniques vary considerably. Although primary suture repair is considered the "benchmark," indirect repair alone has shown comparable outcomes. Given the concern for infection after ID, many have indicated for prolonged prophylactic antibiotic regimens. However, there is little clinical evidence that this is necessary after adequate repair. The addition of subfascial drains have been shown to promote wound healing and early ambulation, whereas no consensus on duration of indwelling drains exists and such management is largely case dependent. Early ambulation after surgery has not shown to be associated with increased risk of further ID complications and decreases rehabilitation time, length of stay, and risk of venous thromboembolism. However, there remains a role for conservation mobilization protocols in more severe cases where notable symptoms are observed.

Cost and Complications of Single-Level Lumbar Decompression in Those Over and Under 75: A Matched Comparison

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

This study aimed to compare costs and complication rates following single-level lumbar decompression in patients under age 75 versus patients aged 75 and older.

SUMMARY OF BACKGROUND DATA

Lumbar decompression is a common surgical treatment for lumbar pathology; however, its effectiveness can be debated in elderly patients because complication rates and costs by age group are not well-defined.

METHODS

The Medicare database was queried through the PearlDiver server for patients who underwent single-level lumbar decompression without fusion as an index procedure. The 90-day complication and reoperation rates were compared between age groups after matching for sex and comorbidity burden. Same day and 90-day costs are compared.

RESULTS

The matched cohort included 89,388 total patients (n = 44,694 for each study arm). Compared to the under 75 age group, the 75 and older age group had greater rates of deep venous thrombosis (odds ratio [OR] 1.443, P = 0.042) and dural tear (OR 1.560, P = 0.043), and a lower rate of seroma complicating the procedure (OR 0.419, P = 0.009). There was no difference in overall 90-day reoperation rate in patients under age 75 versus patients aged 75 and older (9.66% vs. 9.28%, P = 0.051), although the 75 and older age group had a greater rate of laminectomy without discectomy (CPT-63047; OR 1.175, P < 0.001), while having a lower rate of laminotomy with discectomy (CPT-63042 and CPT-63030; OR 0.727 and 0.867, respectively, P = 0.013 and <0.001, respectively). The 75 and older age group had greater same day ($3329.24 vs. $3138.05, P < 0.001) and 90-day ($5014.82 vs. $4749.44, P < 0.001) mean reimbursement.

CONCLUSION

Elderly patients experience greater rates of select perioperative complications, with mildly increased costs. There is no significant difference in overall 90-day reoperation rates.

LEVEL OF EVIDENCE

3.

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.

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.

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

Study Design

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

Purpose

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

Overview of Literature

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

Methods

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

Results

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

Conclusions

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

Natural language processing for automated detection of incidental durotomy

BACKGROUND

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

PURPOSE

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

PATIENT SAMPLE

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

OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The True Effect of a Lumbar Dural Tear on Complications and Cost

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

The aim of this study was to match risk factors for complications in patients who did and did not sustain a dural tear while undergoing posterior lumbar spine surgery and compare local and systemic complications.

SUMMARY OF BACKGROUND DATA

Current data do not adequately define whether the event of sustaining an isolated dural tear increases the risk for postoperative complications while controlling for other confounding risk factors.

METHODS

The PearlDiver Database was queried for patients who underwent posterior lumbar spine decompression and/or fusion for degenerative pathology. Patients with and without dural tears were 1:2 matched based on demographic variables and comorbidities. Complications, cost, length of stay (LOS), and readmission rates were analyzed.

RESULTS

The 1:2 matched cohort included 9038 patients with a dural tear and 17,340 patients without a dural tear. All complications assessed were significantly higher in the dural tear group (P < 0.03). Venothromboembolic (VTE) events occurred in 1.3% of patients with a dural tear and 0.9% of patients without a dural tear (odds ratio [OR] 1.46, P < 0.0001). Meningitis occurred in 25 patients (0.3%) with a dural tear and eight patients (<0.1%) without a dural tear (OR 6.0, P < 0.0001). Patients with a dural tear had 120% higher medical costs, 200% greater LOS, and were two times more likely to be readmitted (P < 0.0001).

CONCLUSION

Sustaining a dural tear while undergoing posterior lumbar spinal decompression and/or fusion for degenerative pathology significantly increased the risk of complications and increased length of stay, risk of readmission, and overall 90-day hospital cost. Dural tears specifically increased the risk of a VTE complication by 1.46 times and meningitis by six times; these are important complications to have a high degree of suspicion for in the setting of durotomy, as they can lead to significant morbidity for the patient.

LEVEL OF EVIDENCE

3.

Recent Preoperative Lumbar Epidural Steroid Injection Is an Independent Risk Factor for Incidental Durotomy During Lumbar Discectomy

STUDY DESIGN

Retrospective review.

OBJECTIVE

To investigate the association between lumbar epidural steroid injection (LESI) and incidental durotomy (ID) in patients with a diagnosis of disc herniation undergoing a primary discectomy.

METHODS

A Medicare patient database was queried for patients between the ages of 65 and 85 years who underwent a primary lumbar discectomy for a diagnosis of lumbar disc herniation or degeneration from 2008 to 2014. Our main cohort of 64 849 patients was then divided into 2 groups: patients who experienced a dural tear (N = 2369) and our matched (age, gender, and history of diabetes) control cohort of patients who did not (N = 62 480). All patients who had a history of LESI were further identified and stratified into 4 subgroups by duration between LESI and discectomy (<3 months, 3-6 months, 6 months to 1 year, and overall), and a comparison of the relative incidence of ID was made among these subgroups. A multivariate logistic regression analysis was employed to determine the relationship between LESI and ID.

RESULTS

Overall incidence of ID was 3.7%. There was a significant difference in incidence of LESI (27.1% vs 35.0%, P < .001) between our control and ID groups. An adjusted odds ratio (OR) showed that prior LESI within 3 to 6 months (OR 1.47, 95% CI 1.20-1.81, P < .001) and within less than 3 months (OR 1.46, 95% CI 1.24-1.72, P < .001) of surgery were significantly associated with ID.

CONCLUSION

LESI increases the risk of ID in patients who undergo a subsequent lumbar discectomy within 6 months of injection.

Prognostic impact of intra- and postoperative management of dural tear on postoperative complications in primary degenerative lumbar diseases

Aims

The aim of this study was to explore risk factors for complications associated with dural tear (DT), including the types of DT, and the intra- and postoperative management of DT.

Patients and Methods

Between 2012 and 2017, 12 171 patients with degenerative lumbar diseases underwent primary lumbar spine surgery. We investigated five categories of potential predictors: patient factors (sex, age, body mass index, and primary disease), surgical factors (surgical procedures, operative time, and estimated blood loss), types of DT (inaccessible for suturing/clipping and the presence of cauda equina/nerve root herniation), repair techniques (suturing, clipping, fibrin glue, polyethylene glycol (PEG) hydrogel, and polyglycolic acid sheet), and postoperative management (drainage duration). Postoperative complications were evaluated in terms of dural leak, prolonged bed rest, headache, nausea/vomiting, delayed wound healing, postoperative neurological deficit, surgical site infection (SSI), and reoperation for DT. We performed multivariable regression analyses to evaluate the predictors of postoperative complications associated with DT.

Results

In total, 429/12 171 patients (3.5%) had a DT. Multivariable analysis revealed that PEG hydrogel significantly reduced the incidence of dural leak and prolonged bed rest, and that patients treated with sealants (fibrin glue and PEG hydrogel) significantly less frequently suffered from headache. A longer drainage duration significantly increased the incidence of headache, nausea/vomiting, and delayed wound healing. Headache and nausea/vomiting were significantly more prevalent in younger female patients. Postoperative neurological deficit and reoperation for DT significantly depended on the presence of cauda equina/nerve root herniation. A longer operative time was the sole independent risk factor for SSI and was also a risk factor for dural leak, prolonged bed rest, and nausea/vomiting.

Conclusion

Sealants, particularly PEG hydrogel, may be useful in reducing symptoms related to cerebrospinal fluid leakage, whereas prolonged drainage may be unnecessary. Younger female patients should be carefully treated when DT occurs. Cite this article: Bone Joint J 2019;101-B:1115–1121.

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

BACKGROUND CONTEXT

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

PURPOSE

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

STUDY DESIGN/SETTING

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

PATIENT SAMPLE

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

OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Elective lumbar fusion in the United States: national trends in inpatient complications and cost from 2002-2014

BACKGROUND

Elective fusions for degenerative spine disease have increased over the past two decades in the United States, with variability in complications and hospital costs. The additional service costs associated with adverse perioperative events remain unknown. Our objective is to improve understanding of trends in safety and cost of elective lumbar fusions on a national scale.

METHODS

A weighted sample of 1,526,386 adults undergoing elective lumbar fusion for degenerative indications were identified in the National Inpatient Sample (NIS) years 2002-2014. Twelve categories of major complications by system, and patient/hospital variables, were evaluated as predictors of the overall reimbursed cost. Mean differences (B) and 95% confidence intervals [95% CI] are reported. Significance is assessed at p<0.001.

RESULTS

Nineteen percent of patients experienced inpatient complication. After adjusting for inflation, the mean overall cost was $32802±19557. Costs increased with presence of each of the 12 categories of complications, and by number of levels fused. Rates of most frequent complications and their adjusted cost-of-care were acute postoperative anemia (11.2%, B=$1817 [$1722-$1913], p<0.001), renal/urinary (1.9%, B=$510 [$288-$732], p<0.001), pulmonary (1.8%, B=$6014 [$5785-6243], p<0.001) and gastrointestinal (1.8%, B=$3699 [$3490-$3908, p<0.001). The costliest adverse events were infection (B=$15882 [$15424-$16339], p<0.001), thromboembolism (B=$8856 [$8400-$9311], p<0.001), hematoma/seroma/vascular (B=$8050 [$7784-$8316], p<0.001).

CONCLUSIONS

The number of elective lumbar fusions for degenerative spine disease increased 276% in the United States from 2002-2014 with growing surgeon preference for lateral techniques, and an increasing proportion of combined anterior and posterior approaches. Overall complication rates decreased from 2002-2014, despite an older patient population. After adjusting for inflation, cost was relatively stable across years 2002-2014. Complications by system were associated with increased cost, underscoring the need to address sources of complications and optimize early postoperative recovery in order to reduce healthcare expenditure.

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.

Lumbar disc herniation: long-term outcomes after mini-open discectomy

PURPOSE

The outcomes of mini open discectomy in lumbar disc herniation are usually satisfying. Our study aims at finding if its results are still good at long-term follow-up.

METHODS

We reviewed 552 patients operated between 1993 and 2013 by mini open discectomy procedure. Our main evaluation criterion is a modified Stauffer and Coventry classification applied during follow-up visits at three months, one year, five years, and every five years. The secondary criterion was the Oswestry Disability Index.

RESULTS

The outcomes are considered good to very good in 87.3% of the cases at one year follow-up. These results deteriorate after an average follow-up of 14.7 years but remain satisfactory with 63.7%. The global decrease is 23.6%. The Oswestry Score decreases by 35 points at the same follow-up. In addition, 6.52% of patients required fusion at first revision and 1.08% at second revision. We also noticed 51 (9.2%) post-operative recurrences at the same level. In 23 (4.16%) of them, we proceeded to a new discectomy in an average interval of 41.4 months. At an adjacent level, 29 patients (5.2%) presented a new symptomatic disc herniation; among them, eight cases (1.44%) needed discectomy. The re-operative rate (including recurrent disc herniation and fusion for degenerative indications) is 10.68% at the last follow-up.

CONCLUSIONS

Nearly 2/3 of our patient series keep satisfactory outcomes after about 15-year follow-up. The mini open discectomy remains a reliable surgical technique provided we respect the indications and surgical requirements. This procedure also avoids excessive instrumentation and its possible iatrogenic complications. Powerful randomized and controlled trials are needed to strengthen these deductions.

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.

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

BACKGROUND CONTEXT

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

PURPOSE

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

STUDY DESIGN/SETTING

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

PATIENT SAMPLE

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

OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

What are the Rates, Reasons, and Risk Factors of 90-day Hospital Readmission After Lumbar Discectomy?: An Institutional Experience

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

To report the rate, reasons, and risk factors for 90-day readmissions after lumbar discectomy at an academic medical center.

SUMMARY OF BACKGROUND DATA

Several studies have reported complications and readmissions after spine surgery; however, only one previous study has focused specifically on lumbar discectomy. As the patient profile and morbidity of various spine procedures is different, focus on procedure-specific complications and readmissions will be beneficial.

MATERIALS AND METHODS

Patients who underwent lumbar discectomy for unrelieved symptoms of prolapsed intervertebral disk and had at least 90 days of follow-up at an academic institution (2013-2014) were included. Retrospective review of electronic medical record was performed to record demographic and clinical profile of patients. Details of lumbar discectomy, index hospital stay, discharge disposition, hospital readmission within 90 days, reason for readmission and treatment given have been reported. Risk factors for hospital readmission were analyzed by multivariate logistic regression analysis.

RESULTS

A total of 356 patients with a mean age of 45.0±13.8 years were included. The 90-day readmission rate was 5.3% (19/360) of which two-third patients were admitted within 30 days giving a 30-day readmission rate of 3.7% (13/356). The top 2 primary reasons for readmission included back and/or leg pain, numbness, or tingling (42.9%), and persistent cerebrospinal fluid leak or seroma (25.0%). On adjusted analysis, risk factors associated with higher risk of readmission included incidental durotomy [odds ratio (OR), 26.2; 95% confidence interval (CI), 5.3-129.9] and discharge to skilled nursing facility/inpatient rehabilitation (OR, 25.2; 95% CI, 2.7-235.2). Increasing age was a negative predictor of readmission (OR, 0.95; 95% CI, 0.91-0.99).

CONCLUSIONS

Incidental durotomy, younger age, and discharge to nursing facility were associated with higher risk of 90-day hospital readmission after lumbar discectomy. As compared with extensive spine procedures, patient comorbidity burden may not be as significant in predicting readmission after this relatively less invasive procedure.

Outcomes and Complications Following Laminectomy Alone for Thoracic Myelopathy due to Ossified Ligamentum Flavum: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Examine the functional outcomes and complications following laminectomy for thoracic myelopathy due to ossification of the ligamentum flavum (OLF).

SUMMARY OF BACKGROUND DATA

OLF is a rare condition that can cause thoracic myelopathy. Laminectomy is a procedure that can be performed to decompress the spinal cord in patients with thoracic myelopathy due to OLF. Few studies have examined postoperative outcomes and complications following laminectomy for thoracic myelopathy secondary to OLF.

METHODS

A systematic review and meta-analysis was performed. Literature search yielded six studies that met our selection criteria. Study characteristics and baseline patient demographics were extracted from each study. Primary outcomes included pre- and postoperative Japanese Orthopedic Association (JOA) scores and perioperative complications including dural tears, cerebrospinal fluid (CSF) leaks, neurological deficits, surgical site infections, and other complications. We calculated pooled proportion estimates for JOA scores and complications using a random effects model.

RESULTS

A total of 137 patients were included. The pooled pre- and postoperative JOA scores were 5.08 (95% confidence interval [CI], 2.70-7.47; I = 98%) and 8.29 (95% CI, 7.73-8.85; I = 18%), respectively, with a mean improvement of +3.03 points (95% CI, 1.08-4.98; I = 88%). Pooled proportion estimates for dural tears, CSF leaks, infections, and early neurological deficits were 18.4% (95% CI, 12.6-26.1; I = 0%), 12.1% (95% CI, 6.6-21.2; I = 0%), 5.8% (95% CI, 2.1-15.4; I = 0%), and 5.7% (95% CI, 2.2-14.3; I = 0%), respectively.

CONCLUSION

Thoracic myelopathy secondary to OLF can be treated with laminectomy. However, despite some improvement in JOA score, functional status remains poor postoperatively. Perioperative complications are common, with dural tears and CSF leaks occurring most frequently. OLF is an uncommon condition and more research is needed to better understand how we can improve the outcomes of laminectomy alone for the treatment of thoracic myelopathy due to OLF.

LEVEL OF EVIDENCE

3.

Medical Malpractice Claims Following Incidental Durotomy Due to Spinal Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Analyze medical malpractice verdicts and settlements associated with incidental durotomy.

SUMMARY OF BACKGROUND DATA

Incidental durotomy is a common complication of spine surgery. Although most intraoperative dural tears are repaired without sequelae, persistent Cerebrospinal Fluid leak, infection, or neurological injury can yield adverse outcomes. The medicolegal implications of incidental durotomy are poorly understood.

METHODS

Three separate, large legal databases were queried for cases involving incidental durotomy. Case, plaintiff, procedure, and outcome characteristics were analyzed.

RESULTS

In total, 48 dural tear-related medical malpractice cases were analyzed. Most cases (56.3%) resulted in a ruling in favor of the defendant physician. Most cases alleged neurological deficits (86.7%). A large majority of cases without neurological sequelae had an outcome in favor of the defendant (83.3%). For cases involving a payment, the average amount was $2,757,298 in 2016 adjusted dollars. Additional surgery was required in 56.3% of cases, a delay in diagnosis/treatment of durotomy was present in 43.8%, and alleged improper durotomy repair was present in 22.9%. A favorable outcome for the plaintiff was more likely in cases with versus without alleged delay in diagnosis/treatment (61.9% vs. 29.6%, P = 0.025) and improper durotomy repair technique (72.7% vs. 35.1%, P = 0.040). Repeat surgery was not associated with favorable outcome for the plaintiff (42.8% cases with reoperation vs. 38.1% without, P = 0.486).

CONCLUSION

This analysis of durotomy-associated closed malpractice claims after spine surgery is the largest yet conducted. Durotomy cannot always be considered an entirely benign event, and these findings have several direct implications for clinicians: late-presenting or dehiscent durotomy may be associated with adverse outcomes and subsequent risk of litigation, timely reoperation in the event of durotomy-related complications may not increase surgeon liability, and spine surgeons should be prepared to defend their choice of durotomy repair technique, should dehiscence occur.

LEVEL OF EVIDENCE

3.

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.

Lumbar Disc Herniation

PURPOSE OF REVIEW

Substantial advancements have been made in the cause, diagnosis, imaging, and treatment options available for patients with lumbar disc herniation (LDH). We examined the current evidence and highlight the concepts on the frontline of discovery in LDH.

RECENT FINDINGS

There are a myriad of novel etiologies of LDH detailed in recent literature including inflammatory factors and infectious microbes. In the clinical setting, recent data focuses on improvements in computer tomography as a diagnostic tool and non-traditional injection options including tumor necrosis alpha inhibitors and platelet-rich plasma. Operative treatment outcomes have focused on minimally invasive endoscopic approaches and demonstrated robust 5-year post-operative outcomes. Advances in the molecular etiology of LDH will continue to drive novel treatment options. The role of endoscopic treatment for LDH will continue to evolve. Further research into10-year outcomes will be necessary as this surgical approach continues to gain widespread popularity.