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

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.

Factors associated with increased length of stay and risk of complications in 336 patients submitted to spine surgery. The role of a validated capture system (SAVES v2) as a first-line tool to properly face the problem

PURPOSE

In this study, we analyzed the use of a validated capture system (Spinal Adverse Events Severity system, SAVES V2) as a first non-technical skill to properly face the relevant problem of surgical complications (SCs) and adverse events (AEs) in spinal surgery.

METHODS

We retrospectively collected AEs occurring in a tertiary referral center for spine surgery from January 2017 to January 2018 and classified them according to SAVES V2 system. We compared this collection of AEs with a prospective collection performed without any classification system. Univariate and multivariate logistic regression models were used to determined odds ratio (ORs) for selected potential risk factors of AEs and prolonged length of stay.

RESULTS

Overall a higher number of AEs was retrospectively recorded using SAVES system compared to the prospective recording without the use of any capture system (97/336 vs 210/336, p < 0.001). The length of stay (LOS) increased in the group of complicated patients for all the procedures examined. In the non-oncological group, LOS was significantly higher for complicated patients compared to uncomplicated patients (F = 44.11, p = 0.0000). Similar results have been obtained in the oncological group of patients. In the multivariate regression model surgical time and postoperative AEs emerged as risk factors for prolonged LOS, while only the presence of previous surgeries was confirmed as risk factor for AEs.

CONCLUSION

Considering that the rate of AEs and SCs in spinal surgery is still high despite the improvement of technical skills, we suggest the use of SAVES V2 capture system as a first-line tool to face the problem.

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.

The Current Status of Awake Endoscopic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

To examine the use of local anesthesia and/or conscious sedation in endoscopic spine procedures within the past decade.

METHODS

This systematic review abided by PRISMA guidelines. Embase, PubMed, Google Scholar, and Cochrane databases were searched for post-2011 articles with patients >18 years old, lumbar/cervical percutaneous endoscopic spine procedures using local/awake anesthesia, and patient/surgical outcomes. Reviews, book chapters, single case reports, or small case series (n ≤15 patients) were excluded. Scoring systems of the National Institutes of Health quality assessment tool, Newcastle-Ottawa Scale, and Cochrane Risk of Bias evaluated interventional case series, comparative studies, and randomized control trials, respectively.

RESULTS

Twenty-six articles were included, with 4 studies comparing general and local anesthesia. Of 2113 total patients, 1873 patients received local anesthesia. Significant improvements were seen in pain and disability scores. Studies that included MacNab scores showed that 96% of patients rated their postoperative satisfaction as excellent to good. Subanalysis of comparative studies showed a reduced risk of surgical/major medical complications and a slight increased risk for minor medical complications among awake spine patients. Length of stay was shorter for patients receiving local anesthesia.

CONCLUSIONS

The current systematic review and meta-analysis shows that use of local anesthesia is a safe and effective alternative to general anesthesia among different endoscopic spinal procedures. Although awake spine surgery is associated with a decreased risk of severe complications, lower revision rates, and higher postoperative satisfaction, more robust studies involving larger cohorts of patients are needed to evaluate the true impact of awake spine surgery on outcomes.

Risk Factors for Cerebrospinal Fluid Leakage After Extradural Spine Surgery: A Meta-Analysis and Systematic Review

BACKGROUND

Cerebrospinal fluid (CSF) leakage is 1 of the common complications of spine surgery and is largely caused by intraoperative or postoperative dural tears. Associations of different factors with postoperative CSF leakage have not been consistent. In this study we aimed to identify demographic, disease-related, and surgical risk factors for CSF leakage after extradural spine surgery in a systematic review and meta-anlysis.

METHODS

The PubMed, EMBASE, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, Chinese Wanfang data, Chinese Weipu Database, and SinoMed databases were searched from inception until October 24, 2022. Fixed-effects or random-effects models were used to calculate odds ratios and 95% confidence intervals. The quality of observational studies was evaluated using the Newcastle-Ottawa scale instrument.

RESULTS

A total of 15 observational studies with 1,719,923 participants were included in this systematic review. All studies had a Newcastle-Ottawa scale score greater than or equal to 6. Age older than 70 years, smoking, ossification of the posterior longitudinal ligament, adhesion of spinal dura, spinal canal stenosis, cervical fracture, spondylolisthesis, revision surgery, and multiple surgical segments were all related to CSF leakage in the pooled analysis. Obesity and disease duration>1 year were not associated with the leakage of CSF.

CONCLUSIONS

This study will provide a reference for the identification of patients at high risk of developing CSF leakage, which suggests clinicians to strengthen the observation of drainage fluid in high-risk groups.

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.

Outcomes of Incidental Durotomy Repair in Thoracolumbar Spine Surgery: An Institutional Experience With Orthopedic Residents

Background The occurrence of incidental durotomies (IDs) following spinal operations is a widely recognized issue. Complications such as poor outcomes, extended hospitalization, prolonged immobilization, infections, and revision surgeries are all potential consequences of inadequate durotomy management during the initial surgery. This study aims to describe the outcomes of ID repair in thoracolumbar spine surgery in terms of the Oswestry Disability Index (ODI) score and visual analog scale (VAS) when performed with the active involvement of orthopedic residents in the surgical procedure. Methodology Between April 2021 and April 2023, a hospital-based observational study was conducted among 110 patients hospitalized in the orthopedic ward at R.L. Jalappa Hospital and Research Center in Kolar, Karnataka, who required IDs due to an accidental dural tear or a postoperative CSF fluid leak following thoracolumbar spine procedures. Patients with a previous history of thoracolumbar spine surgery, vertebral tumors, spinal metastasis, infections, e.g., spondylodiscitis, or Pott's spine were excluded. The ODI score and VAS score were calculated on the postoperative day, one month, and three months following surgery. Results The mean age of the study participants was 62.81 + 10.49 years, with a male preponderance of 67.2% among the study participants. The mean BMI of study participants was 23.77 kg/m2. Approximately 24.5% of participants had a prior history of spinal surgery. Among 110 patients, 32 had postoperative complications. Six patients reported experiencing urinary retention, followed by five with CSF leakage and one with a postural headache (five cases). Based on the ODI score, mild disability was seen in 32.7% of the study samples at three months of follow-up. Based on the VAS score, moderate pain was seen among all the study samples at three months of follow-up. The ANOVA test revealed statistically significant differences in ODI and VAS score reductions between the immediate postoperative period and the one-month and three-month follow-up periods (p = 0.001 and p = 0.0247, respectively). Conclusion Less than one-third of the samples had postoperative complications. At three months, ODI scores showed mild disability in one-third of the study samples. At three months, all study samples had moderate VAS pain. The improvement in ODI and VAS scores from the day after surgery through the one-month and three-month follow-up periods was statistically significant.

The effect of subcutaneous fat and skin-to-lamina distance on complications and functional outcomes of minimally invasive lumbar decompression

PURPOSE

Minimally invasive lumbar decompression (MIS) in obese pzatients is technically challenging due to the use of longer tube retractors. The purpose of this study was to evaluate the impact of the thickness of the soft tissue and subcutaneous fat on complications, revisions, and patient-reported functional outcomes after MIS.

METHODS

This is a retrospective analysis of 148 consecutive patients who underwent minimally invasive lumbar decompression at our institute between 2013 and 2017 and had at least one year of follow-up. Analysis was performed five times, each time the study group was defined by another measure of adiposity: BMI > 30, skin to lamina distance at the site of surgery and at L4 > 6 cm, and subcutaneous fat thickness at the site of surgery and at L4 > 3 cm. Outcomes included intraoperative complications (durotomy or neurological deficit), possibly inadequate decompression (residual disc, reoperation), length of stay, return to the emergency room or readmission, postoperative medical complications, and functional outcomes: visual analog scores for back and leg pain, and Oswestry Disability Index (ODI).

RESULTS

Patients with a thicker layer soft tissue had a significantly higher burden of comorbidities than controls, including higher prevalence of cardiovascular disease (p = 0.002), diabetes (p < 0.001), hypertension (p < 0.001) and higher ASA scores (p = 0.002). Nevertheless, there was no significant difference between the patient groups in surgical and medical complications, functional outcomes, and other assessed outcomes.

CONCLUSION

Our results indicate that minimally invasive lumbar decompression is safe and effective for patients with a thick layer of soft tissue and subcutaneous fat.

Does Tobacco Smoking Affect the Postoperative Outcome of MIS Lumbar Decompression Surgery?

BACKGROUND

Tobacco smoking is a major cause of morbidity and mortality worldwide. Several authors reported a significant negative impact of smoking on the outcome of spinal surgeries. However, comparative studies on the effect of smoking on the outcome of minimally invasive (MIS) spinal decompression are rare with conflicting results. In this study, we aimed to evaluate clinical outcomes and postoperative complications following MIS decompression in current and former smoking patients compared to those of non-smoking patients.

METHODS

We used our prospectively collected database to retrospectively analyse the records of 188 consecutive patients treated with MIS lumbar decompression at our institution between November 2013 and July 2017. Patients were divided into groups of smokers (S), previous smokers (PS) and non-smokers (N). The S group and the PS group comprised 31 and 40 patients, respectively. The N group included 117 patients. The outcome measures included perioperative complications, revision surgery and length of stay. Patient-reported outcome measures included a visual analogue scale (VAS) for back pain and leg pain, as well as the Oswestry disability index (ODI) for evaluating functional outcomes.

RESULTS

Demographic variables, comorbidity and other preoperative variables were comparable between the three groups. A comparison of perioperative complications and revision surgery rates showed no significant difference between the groups. All groups showed significant improvement in their ODI and VAS scores at 12 and 24 months following surgery. As shown by a multivariate analysis, current smokers had lower chances of improvement, exceeding the minimal clinical important difference (MCID) in ODI and VAS for leg pain at 12 months but not 24 months postoperatively.

CONCLUSIONS

Our findings show that except for a possible delay in improvement in leg pain and disability, tobacco smoking has no substantial adverse impact on complications and revision rates following MIS spinal decompressions.

Subdural hygroma as a rare complication after revision spine surgery

Spinal fusion surgery is the most commonly performed orthopaedic surgical procedure. However, subdural hygroma occurrence is a very rare complication after revision spinal fusion surgery. Here, we report a case of revision lumbar fusion surgery at the L3-4 level. The patient developed acute conus medullaris syndrome at 10 days postoperatively. MRI showed a subdural, extra-arachnoid area fluid collection following the T12-L2, cephalad to the area of revision spinal fusion. When patients have a decreased motor grade, difficulty in voiding urine and neurological abnormalities after lumbar spine surgery, conus medullaris syndrome with a possible occurrence of subdural hygroma should be considered. In this situation, immediate imaging investigations and emergency surgery might be necessary to reduce the pressure on the spinal cord.

Incidence and Characteristics of Clinical L5-S1 Adjacent Segment Degeneration after L5 Floating Lumbar Fusion: A Multicenter Study

STUDY DESIGN

Retrospective study.

PURPOSE

This study aimed to evaluate the incidence, characteristics, and risk factors for clinical L5-S1 adjacent segment degeneration (ASD) after L5 floating lumbar fusion.

OVERVIEW OF LITERATURE

ASD is known to occur after lumbar spine fusion at a certain frequency. Several studies on radiological L5- S1 ASD have been reported. However, there are only a few studies on L5-S1 ASD with clinical symptoms, including back pain and/or radiculopathy.

METHODS

In total, 306 patients who received L5 floating lumbar fusion were included in this study. Clinical L5-S1 ASD was defined as newly developed radiculopathy in relation to the L5-S1 segment. Patients' medical records and imaging data were retrospectively analyzed. The risk factors for clinical ASD were assessed by an inverse probability of treatment weighting-adjusted logistic regression analysis.

RESULTS

Clinical L5-S1 ASD occurred in 17 patients (5.6%). The mean onset time of L5-S1 ASD was 12.9±7.5 months after the primary surgery. Among these patients, 10 (58.8%) presented with clinical L5-S1 ASD within 12 months. Reoperation was performed in three patients (1.0%). The severity of L5-S1 disk degeneration did not affect the occurrence of L5-S1 ASD. Logistic regression analysis showed that the number of fusion levels was a significant risk factor for clinical L5-S1 ASD.

CONCLUSIONS

The incidence and characteristics of clinical L5-S1 ASD after L5 floating lumbar fusion were retrospectively investigated. This study established that the number of fusion levels was a significant candidate factor for clinical L5-S1 ASD. Careful clinical follow-up is deemed necessary after L5 floating lumbar fusion surgery, especially for patients who received multiple-level fusions.

En bloc resection of ligamentum flavum with laminotomy of the caudal lamina in the minimally invasive laminectomy: surgical anatomy and technique

OBJECTIVE

A CSF leak is a potential complication in a lumbar laminectomy. An analysis of the author's surgical experience identified inadvertent durotomies that occurred when resecting the ligamentum flavum at its insertion into the superior aspect of the caudal lamina. Anatomical analyses of the lumbar canal diameter demonstrate that the insertion point of the caudal ligamentum flavum is the most constrained area of the canal. The surgical technique was modified to eliminate the need for direct action in that anatomical region after the author compared the efficacy of piecemeal resection of the ligamentum flavum with en bloc resection with a laminotomy of the caudal lamina beyond the insertion point of the ligamentum flavum in the lumbar laminectomy.

METHODS

An analysis of a single surgeon's experience managing 147 consecutive patients with lumbar stenosis who underwent single-level lumbar hemilaminectomies over a 4-year period was performed. Patients were managed with either piecemeal resection (cohort 1) or en bloc resection with a laminotomy beyond the caudal insertion (cohort 2) of the ligamentum flavum.

RESULTS

Seventy-seven patients underwent piecemeal resection (cohort 1), and 70 underwent en bloc resection (cohort 2). There were 5 CSF leaks (6.4%) in cohort 1. There were no CSF leaks in cohort 2. There was a statistically significant difference in operative times between the two groups (p = 0.04), but there was no statistically significant difference in patient-reported outcomes at 6 months between the groups.

CONCLUSIONS

En bloc resection of the ligamentum flavum with a laminotomy below the caudal insertion point appears to decrease the risk of a CSF leak by working beyond the most constrained diameter of the lumbar canal to release the caudal insertion of the ligamentum flavum.

Incidental dural tears associated with worse clinical outcomes in patients operated for lumbar spinal stenosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Incidental dural (ID) tear is a common complication of spine surgery with a prevalence of 4-10%. The association between ID and clinical outcome is uncertain. Former studies found only minor differences in Oswestry Disability Index (ODI). We aimed to examine the association of ID with treatment failure after surgery for lumbar spinal stenosis (LSS).

METHODS

Between 2007 and 2017, 11,873 LSS patients reported to the national Norwegian spine registry (NORspine), and 8,919 (75.1%) completed the 12-month follow-up. We used multivariate logistic regression to study the association between ID and failure after surgery, defined as no effect or any degrees of worsening; we also compared mean ODI between those who suffered a perioperative ID and those who did not.

RESULTS

The mean (95% CI) age was 66.6 (66.4-66.9) years, and 52% were females. The mean (95% CI) preoperative ODI score (95% CI) was 39.8 (39.4-40.1); all patients were operated on with decompression, and 1125 (12.6%) had an additional fusion procedure. The prevalence of ID was 4.9% (439/8919), and the prevalence of failure was 20.6% (1829/8919). Unadjusted odds ratio (OR) (95% CI) for failure for ID was 1.51 (1.22-1.88); p < 0.001, adjusted OR (95% CI) was 1.44 (1.11-1.86); p = 0.002. Mean postoperative ODI 12 months after surgery was 27.9 for ID vs. 23.6 for no ID.

CONCLUSION

We demonstrated a significant association between ID and increased odds for patient-reported failure 12 months after surgery. However, the magnitude of the detrimental effect of ID on the clinical outcome was small.

Are Octogenarians at Higher Risk of Complications After Elective Lumbar Spinal Fusion Surgery? Analysis of a Cohort of 7880 Patients From the Kaiser Permanente Spine Registry

STUDY DESIGN

A retrospective cohort study with chart review.

OBJECTIVE

To determine if there is a difference in risk of adverse outcomes following elective posterior instrumented lumbar spinal fusions for patients aged 80 years and above compared with patients aged 50 to 79 years.

SUMMARY OF BACKGROUND DATA

Patients aged 80 years and above are undergoing elective lumbar spinal fusion surgery in increasing numbers. There are conflicting data on the risks of intraoperative and postoperative complications in these patients.

MATERIALS AND METHODS

Patients aged 80 years and above were compared with 50 to 79 years (reference group) using time-dependent multivariable Cox proportional hazards regression with a competing risk of death for longitudinal outcomes and multivariable logistic regression for binary outcomes. Outcome measures used were: (1) intraoperative complications (durotomy), (2) postoperative complications: 30-day outcomes (pneumonia); 90-day outcomes (deep vein thrombosis, pulmonary embolism, emergency room visits, readmission, reoperations, and mortality); and two-year outcomes (reoperations and mortality).

RESULTS

The cohort consisted of 7880 patients who underwent primary elective posterior instrumented lumbar spinal fusion (L1-S1) for degenerative disk disease or spondylolisthesis. This was subdivided into 596 patients were aged 80 years and above and 7284 patients aged 50 to 79. After adjustment, patients aged 80 years and above had a higher likelihood of durotomy [odds ratio (OR)=1.43, 95% confidence interval (CI)=1.02-2.02] and 30-day pneumonia (OR=1.81, 95% CI=1.01-3.23). However, there was a lower risk of reoperation within two years of the index procedure (hazard ratio=0.69, 95% CI=0.48-0.99). No differences were observed for mortality, readmissions, emergency room visits, pulmonary embolism, or deep vein thrombosis.

CONCLUSIONS

In a cohort of 7880 elective posterior instrumented lumbar fusion patients for degenerative disk disease or spondylolisthesis, we did not observe any significant risks of adverse events between patients aged 80 years and above and those aged 50 to 79 except for higher durotomies and 30-day pneumonia in the former. We believe octogenarians can safely undergo lumbar fusions, but proper preoperative screening is necessary to reduce the risks of 30-day pneumonia.

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.

Lumbar spinal stenosis - surgical outcome and the odds of revision-surgery: Is it all due to the surgeon?

BACKGROUND

Surgical decompression is the intervention of choice for lumbar spinal stenosis (LSS) when non-operative treatment has failed. Apart from acute complications such as hematoma and infections, same-level recurrent lumbar stenosis and adjacent-segment disease (ASD) are factors that can occur after index lumbar spine surgery.

OBJECTIVE

The aim of this retrospective case series was to evaluate the outcome of surgery and the odds of necessary revisions.

METHODS

Patients who had undergone either decompressive lumbar laminotomy or laminotomy and spinal fusion due to lumbar spinal stenosis (LSS) between 2000 and 2011 were included in this analysis. Demographic, perioperative and radiographic data were collected. Clinical outcome was evaluated using numeric rating scale (NRS), the symptom subscale of the adapted version of the german Spinal Stenosis Measure (SSM) and patient-sreported ability to walk.

RESULTS

Within the LSS- cohort of 438 patients, 338 patients underwent decompression surgery only, while instrumentation in addition to decompression was performed in 100 cases (22.3%). 38 patients had prior spinal operations (decompression, disc herniation, fusion) either at our hospital or elsewhere. Thirty-five intraoperative complications were documented with dural tear with CSF leak being the most common (33/35; 94.3%). Postoperative complications were defined as complications that needed surgery and differentiated between immediate postoperative complications (⩽ 3 weeks post operation) and complications that needed revisions surgery at a later date. Within all patients 51 revisions were classified as immediate complications of the index operation with infections, neurological deficits and hematoma being the most common. Within this group only 22 patients had fusion surgery in the first place, while 29 were treated by decompression. Revision surgery was indicated by 53 patients at a later date. While 4 patients decided against surgery, 49 revision surgeries were planned. 28 were performed at the same level, 10 at the same level plus an adjacent level, and 10 were executed at index level with indications of adjacent level spinal stenosis, adjacent level spinal stenosis plus instability and stand-alone instability. Pre- operative VAS score and ability to walk improved significantly in all patients.

CONCLUSIONS

While looking for predictors of revision surgery due to re-stenosis, instability or same/adjacent segment disease none of these were found. Within our cohort no significant differences concerning demographic, peri-operative and radiographic data of patients with or without revision wer noted. Patients, who needed revision surgery were older but slightly healthier while more likely to be male and smoking. Surprisingly, significant differences were noted regarding the distribution of intraoperative and early postoperative complications among the 6 main surgeons while these weren't obious within the intial index group of late revisions.

Incidence and risk factors for incidental durotomy in spine surgery for lumbar stenosis and herniated disc

PURPOSE

Incidental durotomy (ID) is one of the most common complications in degenerative surgery. Due to the negative consequences of ID, knowledge about incidence and risk factors is warranted.

METHODS

A total of 1,139 surgical procedures for lumbar spinal stenosis (LS) and lumbar herniated disc (LDH) were included from the spine surgery database: DaneSpine. Uni- and multivariate analyses were performed for the assessment of possible risk factors.

RESULTS

ID occurred in 10.4% of the surgical procedures. A multivariate regression analysis revealed an increased relative risk of ID by 2% per year of age, 58% by revision surgery, and 55% by decompression on multiple levels.

CONCLUSION

In our single-centre cohort study, one in ten patients experiences an ID. Increasing age, revision surgery and decompression of multiple levels are risk factors of ID in degenerative surgery of the lumbar spine.

Repair of Incidental Durotomy Using Sutureless Nonpenetrating Clips via Biportal Endoscopic Surgery

STUDY DESIGN

Technical report.

OBJECTIVES

Dural tear is one of the most common complications of endoscopic spine surgery. Although endoscopic dural repair of the durotomy area may be difficult, we successfully repaired the dural tear area using nonpenetrating clips during biportal endoscopic surgery. We introduce the surgical technique of dural repair using nonpenetrating titanium clips in biportal endoscopic spine surgery and report its clinical outcome.

METHODS

We retrospectively reviewed and analyzed 5 patients who were treated via primary dural repair using nonpenetrating titanium clips during biportal endoscopic lumbar surgery. The 2 methods of dural clipping and repair include 2 or 3 portals. We analyzed radiological parameters such as cerebrospinal fluid collection as well as clinical parameters, including postoperative clinical outcomes.

RESULTS

Five patients underwent biportal endoscopic dural repair using nonpenetrating clips. Incidental durotomy was successfully repaired using nonpenetrating titanium clips in all 5 patients. No cerebrospinal fluid collection was detected in the postoperative magnetic resonance images. Clinically, preoperative symptoms improved significantly after surgery (P < .05).

CONCLUSIONS

We repaired the dural tear area completely using nonpenetrating titanium vascular anastomosis clips in biportal endoscopic lumbar surgery. Dural repair via clipping method may be an effective alternative for incidental durotomy.

No Benefit with Preservation of Midline Structures in Decompression for Lumbar Spinal Stenosis: Results From the National Swedish Spine Registry 2-Year Post-Op

STUDY DESIGN

Observational cohort study.

OBJECTIVE

The aim of this study was to investigate whether preservation of the midline structures is associated with a better clinical outcome compared to classic central decompression for lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

The classic surgical procedure for LSS is a central, facet joint sparing decompressive laminectomy (LE). Alternative approaches have been developed to preserve the midline structures. The effect of the alternative techniques compared to LE remains unclear.

METHODS

All patients >50 years of age who underwent decompression surgery for LSS without concomitant fusion in the National Swedish Spine Registry (Swespine) from December 31, 2015 until October 6, 2017 were included in this study based on surgeon-reported data and patient questionnaires before and 2 years postoperatively. Propensity score matching was used to compare decompression with preservation of midline structures with patients who underwent LE. The primary outcome was the Oswestry Disability Index (ODI) and secondary outcomes were the Numeric Rating Scale (NRS) for leg and back pain, EuroQol-5 Dimensions (EQ-5D), Global Assessment (GA), patient satisfaction and rate of subsequent surgery.

RESULTS

Some 3339 patients completed a 2-year follow-up. Of these, 2974 (89%) had decompression with LE and 365 underwent midline preserving surgery. Baseline scores were comparable between the groups. Mean ODI improvement at follow-up was 16.6 (SD = 20.0) in the LE group and 16.9 (SD = 20.2) in the midline preserving surgery group. In the propensity score-matched analysis the difference in improved ODI was 0.53 (95% confidence interval, CI -1.71 to 2.76; P = 0.64). The proportion of patients who showed a decreased ODI score of at least our defined minimal clinically important difference (=8) was 68.3% after LE and 67.0% after preserving the midline structures (P = 0.73). No significant differences were found in the improvement of NRS for leg and back pain, EQ-5D, GA or patient satisfaction. The rate of subsequent surgery was 5.5% after LE and 4.9% after midline preserving surgery without a significant difference in the propensity score-matched analysis (hazard ratio, HR 0.87; 95% CI 0.49-1.54; P = 0.64).

CONCLUSION

In this study on decompression techniques for LSS, there was no benefit in preserving the midline structures compared to LE 2 years after decompression. The conclusion is that the surgeon is free to choose the surgical method that is thought most suitable for the patient and the condition with which the patient presents.Level of Evidence: 3.

Risk factors and management strategies for cerebrospinal fluid leakage following lumbar posterior surgery

OBJECTIVE

To analyze the risk factors of cerebrospinal fluid leakage (CSFL) following lumbar posterior surgery and summarize the related management strategies.

METHODS

A retrospective analysis was performed on 3179 patients with CSFL strategies lumbar posterior surgery in our hospital from January 2019 to December 2020. There were 807 cases of lumbar disc hemiation (LDH), 1143 cases of lumbar spinal stenosi (LSS), 1122 cases of lumbar spondylolisthesis(LS), 93 cases of lumbar degenerative scoliosis(LDS),14 cases of lumbar spinal benign tumor (LST). Data of gender, age, body mass index(BMI), duration of disease, diabete, smoking history, preoperative epidural steroid injection, number of surgical levels, surgical methods (total laminar decompression, fenestration decompression), revision surgery, drainage tube removal time, suture removal time, and complications were recorded.

RESULTS

The incidence of 115 cases with cerebrospinal fluid leakage, was 3.6% (115/3179).One-way ANOVA showed that gender, body mass index (BMI), smoking history, combined with type 2 diabetes and surgical method had no significant effect on CSFL (P > 0.05). Age, type of disease, duration of disease, preoperative epidural steroid injection, number of surgical levels and revision surgery had effects on CSFL (P < 0.05). Multivariate Logistic regression analysis showed that type of disease, preoperative epidural steroid injection, number of surgical levels and revision surgery were significantly affected CSFL (P < 0.05).Drainage tube removal time of CSFL patients ranged from 7 to 11 days, with an average of 7.1 ± 0.5 days, drainage tube removal time of patients without CSFL was 1-3 days, with an average of 2.0 ± 0.1 days, and there was a statistical difference between the two groups (P < 0.05).The removal time of CSFL patients was 12-14 days, with an average of 13.1 ± 2.7 days, and the removal time of patients without CSFL was 10-14 days, with an average of 12.9 ± 2.2 days, there was no statistically significant difference between the two groups (P > 0.05).

CONCLUSION

Type of disease, preoperative epidural steroid injection, number of surgical levels and revision surgery were the risk factors for CSFL. Effective prevention were the key to CSFL in lumbar surgery. Once appear, CSFL can also be effectively dealt without obvious adverse reactions after intraoperative effectively repair dural, head down, adequate drainage after operation, the high position, rehydration treatment, and other treatments.

Perspective on the integration of optical sensing into orthopedic surgical devices

SIGNIFICANCE

Orthopedic surgery currently comprises over 1.5 million cases annually in the United States alone and is growing rapidly with aging populations. Emerging optical sensing techniques promise fewer side effects with new, more effective approaches aimed at improving patient outcomes following orthopedic surgery.

AIM

The aim of this perspective paper is to outline potential applications where fiberoptic-based approaches can complement ongoing development of minimally invasive surgical procedures for use in orthopedic applications.

APPROACH

Several procedures involving orthopedic and spinal surgery, along with the clinical challenge associated with each, are considered. The current and potential applications of optical sensing within these procedures are discussed and future opportunities, challenges, and competing technologies are presented for each surgical application.

RESULTS

Strong research efforts involving sensor miniaturization and integration of optics into existing surgical devices, including K-wires and cranial perforators, provided the impetus for this perspective analysis. These advances have made it possible to envision a next-generation set of devices that can be rigorously evaluated in controlled clinical trials to become routine tools for orthopedic surgery.

CONCLUSIONS

Integration of optical devices into surgical drills and burrs to discern bone/tissue interfaces could be used to reduce complication rates across a spectrum of orthopedic surgery procedures or to aid less-experienced surgeons in complex techniques, such as laminoplasty or osteotomy. These developments present both opportunities and challenges for the biomedical optics community.

Stable Low-Grade Degenerative Spondylolisthesis Does Not Compromise Clinical Outcome of Minimally Invasive Tubular Decompression in Patients with Spinal Stenosis

Background and Objectives: In recent literature, the routine addition of arthrodesis to decompression for lumbar spinal stenosis (LSS) with concomitant stable low-grade degenerative spondylolisthesis remains controversial. The purpose of this study is to compare the clinical outcome, complication and re-operation rates following minimally invasive (MIS) tubular decompression without arthrodesis in patients suffering from LSS with or without concomitant stable low-grade degenerative spondylolisthesis. Materials and Methods: This study is a retrospective review of prospectively collected data. Ninety-six consecutive patients who underwent elective MIS lumbar decompression with a mean follow-up of 27.5 months were included in the study. The spondylolisthesis (S) group comprised 53 patients who suffered from LSS with stable degenerative spondylolisthesis, and the control (N) group included 43 patients suffering from LSS without spondylolisthesis. Outcome measures included complications and revision surgery rates. Pre- and post-operative visual analog scale (VAS) for both back and leg pain was analyzed, and the Oswestry Disability Index (ODI) was used to evaluate functional outcome. Results: The two groups were comparable in most demographic and preoperative variables. VAS for back and leg pain improved significantly following surgery in both groups. Both groups showed significant improvement in their ODI scores, at one and two years postoperatively. The average length of hospital stay was significantly higher in patients with spondylolisthesis (p-value< 0.01). There was no significant difference between the groups in terms of post-operative complications rates or re-operation rates. Conclusions: Our results indicate that MIS tubular decompression may be an effective and safe procedure for patients suffering from LSS, with or without degenerative stable spondylolisthesis.

Seizures following cervical laminectomy and lateral mass fusion: case report and review of the literature

Incidental durotomy can occur as a complication of spine surgery, which may potentially result in serious intracranial complications. We report a case of a 72 years old male with significant cervical spinal stenosis from C3 to C5 with spinal cord myelomalacia who underwent a posterior cervical decompression with instrumentation and fusion from C3-C5. An incidental dural tear was encountered during the surgery, with a sudden gush of cerebrospinal fluid (CSF) managed intraoperatively. Unfortunately, he developed generalized tonic-clonic seizures subsequently in the immediate post-operative period. Computerized tomography (CT) scan was urgently done which revealed intracranial pneumocephalus, subarachnoid hemorrhage and a right acute subdural hematoma. This case illustrates the intracranial hemorrhage potential subsequent to iatrogenic dural tear and CSF leak manifested by generalized seizures. The repair of incidental durotomy should be done immediately to decrease the amount of CSF leak and prevent any devastating effects of intracranial hemorrhage. The mechanism of this type of bleeding, risk factors and appropriate management are discussed, along with a review of the literature.

Immediate postoperative MRI findings after lumbar decompression surgery: Correlation of imaging features with clinical outcome

An understanding of the common MRI findings observed after decompression surgery is important. However, to date, no study addressing this has been published. The aim of this study was to analyze and describe the immediate postoperative MRI findings after lumbar decompression surgery. We retrospectively analyzed the immediate postoperative MRIs of 121 consecutive patients who underwent lumbar decompression surgery between July 2017 and June 2018. Changes in stenosis at the decompressed and adjacent levels, epidural fat edema, epidural and subdural fluid collections, nerve root swelling, facet joint effusions, intervertebral disc signal, and paravertebral muscle edema were correlated with clinical characteristics. Both groups had reduced central canal stenosis postoperatively (p < 0.001) but worsened stenosis at adjacent segments. Fluid collection, hemorrhagic or non-hemorrhagic, at the laminectomy site was the commonest finding (one-level: 73.8%, two-level: 88.5%), with a higher percentage of severe central canal compromise in the two-level decompression group (p = 0.003). Other postoperative MRI findings, such as epidural fat edema, nerve root swelling, subdural fluid collection, and facet joint effusion, were noted without statistical significance. In conclusion, even with successful decompression for lumbar canal stenosis, increased central canal stenosis at adjacent segments is common on immediate postoperative MRI scans, showing no statistically significant correlation with the immediate postoperative outcome. Postoperative fluid collection at the laminectomy site is the commonest imaging finding, and higher rates of hemorrhagic fluid and more severe central canal compromise occur in two-level decompression, but rarely cause clinical problems.

Comparison of Transthecal Approach With Traditional Conservative Approach for Primary Closure After Incidental Durotomy in Anterior Lumbar Tear

BACKGROUND

Incidental durotomies (IDs) are frequent complications of spinal surgeries which are mostly posterior or lateral. Anterior IDs are rare; however, they may lead to severe complications. We compared the transthecal approach with the conservative approach for primary closure after durotomy in anterior lumbar dural tear to assess the efficacy of these approaches to decrease postsurgical complications and clinical outcomes.

METHODS

A total of 21 patients undergoing L2-S1 laminectomy with anterior ID were randomly divided into a transthecal group (n = 9) and a conservative group (n = 12) based on the surgical dural closure technique. Postoperative pseudomeningocele, wound infection, rootlet herniation, pneumocephalus, cerebrospinal fluid (CSF) leakage, headache, meningitis, in addition to surgery duration and length of hospitalization were examined and compared in both groups.

RESULTS

The frequency of pseudomeningocele and CSF leakage in patients undergoing the transthecal approach was significantly lower than those undergoing the conservative approach (P = .045 and .008, respectively). Furthermore, although the differences in the frequency of meningitis, pneumocephalus, headache, and wound infection were not statistically significant between the 2 groups, the effect sizes of the comparison were obtained as 49.4, 19.8, 7.1, and 2.6, respectively. This indicated that the differences were clinically significant between the 2 groups.

CONCLUSIONS

We found that the transthecal approach was significantly more successful in managing CSF leakage as well as its complications and clinical outcomes. However, further clinical trials with bigger sample sizes are needed to substantiate this claim.

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 Outcomes of Incidental Dural Tears During Lumbar Microdiscectomy

Background: A dural tear (DT) is the most commonly encountered complication during lumbar spine surgery. The incidence of DT increases depending on the complexity of the surgical procedure and the presence of a DT is related to a poor outcome and patient satisfaction.

Objectives: This study aimed to determine the incidence and clinical outcomes of DTs in those patients who undergo lumbar disc surgery.

Methods: We retrospectively reviewed consecutive patients who underwent surgery for the management of a primary single-level lumbar disc herniation at a single institution between 2004 and 2014. Among the studied population, those with DTs were included in the study group. An age- and sex-matched group of randomly selected patients who underwent the same level and type of lumbar spine surgery, but did not develop DTs, were assigned as the control group. The outcomes were compared at 12 months postoperatively between the groups.

Results: A total of 5,476 consecutive patients (2,608 female, 2,868 male; mean age, 54 ± 11.45 [range, 21-86] years) underwent surgery for primary single-level lumbar disc herniation. DT was noted in 192 (2.85%) cases. Of these, 102 patients with complete data were included in the DT group. The DT group had a significantly increased length of hospital stay (p = 0.001). Also, the duration of bed rest in the hospital was significantly higher in patients wherein DT was repaired using hemostatic material and fibrin glue, compared to the patients with primary closure with suturing of the tear.

Conclusion: Incidental DTs, if recognized and treated appropriately, will not lead to poor clinical results and do not adversely impact postoperative outcomes.

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.

There is no difference in perioperative results between posterior instrumentation with and without interbody cage and debridement in primary spondylodiscitis in adults. A multicenter surveillance study from the German Spine Registry (DWG-Register)

BACKGROUND

Primary spondylodiscitis is a medically challenging disease that can lead to recurrent back pain, progressive kyphotic deformity, and neurologic deficits. The incidence rate of primary non-tuberculosis spondylodiscitis has been estimated from 2.2 to 2.4 cases per 100,000 person-years, and it has been reported to be increasing because of the aging population. The objectives were to determine the safety and efficacy of posterior instrumentation (PI) with and without interbody cage, bony attachment and debridement in the treatment of primary spondylodiscitis by comparing perioperative data, functional outcomes, and overall infection-free survival.

METHODS

Analysis of data from the DWG registry on patients who have undergone posterior instrumentation with and without interbody cage, bony attachment and debridement in primary spondylodiscitis from the thoracolumbar junction to S1 (Th10-S1) at 10 institutions from January 2012 to December 2016.

RESULTS

In total, 420 posterior instrumentations with and without interbody cage, bony attachment and debridement in primary spondylodiscitis in the thoracolumbar junction to S1 were identified in the registry; n=138 were exclusively percutaneous posterior instrumented (PPI), while n=102 underwent open posterior instrumentation (OPI) without interbody cage, bony attachment and debridement and n=180 OPI with interbody cage, bony attachment and debridement. Clinical evaluation after surgery did not show a significant difference between groups including improvement of the mbilisation and infection-free survival. However, with PPI the duration of operation and blood loss was significantly less than OPI with and without interbody cage, bony attachment and debridement.

CONCLUSIONS

The results suggest interbody cage, bony attachment and debridement as not indispensable for treatment in primary spondylodiscitis. Therefore, we encourage the use of posterior stabilization alone in the treatment of spondylodiscitis as less invasive procedure reducing costs in instrumentation.

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.

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.

Symptomatic Postoperative Spinal Subdural Extra-Arachnoid Hygromas: Resolution with Conservative Management: A Report of 2 Cases

CASE

Two cases of postoperative spinal subdural extra-arachnoid hygromas were successfully treated with bed rest after patients developed symptoms 4 to 5 days following decompressive lumbar surgery. The development of the hygromas as well as the radiological findings are discussed.

CONCLUSION

To the best of our knowledge, these comprise the first postoperative cases successfully treated without surgical re-exploration. This demonstrates conservative management may be a safe and effective management choice.

Targeted Epidural Blood Patches Under Fluoroscopic Guidance For Incidental Durotomies Related To Spine Surgeries: A Case Series

Introduction

Incidental durotomies are usually managed conservatively. However, 1.8% of patients require surgical dural repair for CSF leak. There are limited data available regarding the use of epidural blood patches (EBP) for persistent CSF leaks secondary to incidental durotomies. This case series aims to evaluate the efficacy of targeted EBPs under fluoroscopic guidance in the treatment of incidental durotomies.

Methods

Four patients with incidental durotomies after spine surgeries (one cervical decompression, one revision of L5-S1 decompression and fusion, and two lumbar decompressions) were included in this series. These patients did not respond to conservative management and subsequently underwent EBPs. Magnetic resonance imaging (MRI) images were reviewed to confirm and identify the sites of CSF leak prior to the EBPs. We targeted the sites of CSF leak with fluoroscopic guidance. All four patients received an EBP with an 18-gauge epidural needle placed under fluoroscopic guidance. In some cases, epidural catheters were used to further target the sites of CSF leak. Contrast was used to confirm the appropriate placements of the needles and catheters. Approximately 5–14 mL of autologous blood was injected through the needles or catheters to the sites of dural leak.

Results

Three lumbar and two cervical EBPs were performed in four patients (two females and two males). Their age ranged from 44 to 73 years old. Two out of three patients who had lumbar EBP reported complete resolution of symptoms following EBP. The patient who had cervical epidural patches did not have improvement in her symptoms.

Conclusion

This case series demonstrated that targeted EBP can be an effective treatment for CSF leak from incidental durotomies. However, dural tears in the cervical region may be more difficult to treat. Larger scale studies are required to evaluate efficacy of EBP in the treatment of symptomatic incidental durotomies.

Invasiveness has no influence on the rate of incidental durotomies in surgery for multisegmental lumbar spinal canal stenosis (≥ 3 levels) with and without fusion. Analysis from the German Spine Registry data (DWG-Register)

BACKGROUND

Nowadays, perioperative complications as dural tear (DT) with subsequent neurological deficits are documented in independent registers. However, the relationship of these complications with the grade of invasiveness (≥3 levels) is still unclear. We attempted to evaluate perioperative complications, particularly DT with subsequent neurological deficits, between patients undergoing laminotomy and decompression and decompression and fusion in ≥3 levels.

METHODS

Retrospective analysis of the data pool of the DWG register based on cases described by 10 clinics between January 2012 and December 2016 was performed. Surgically treated LSS in ≥3 segments were divided into decompression with or without instrumentation and fusion. Cases with intraoperative DT in both subgroups were analysed for risk factor occurrence. The Surgical Invasive Index (SII) was used.

RESULTS

DT occurred in 102/941 (10.8%) patients. Difference in DT between groups was non- significant. The likelihood of DT increased by 2.12-fold with previous spinal surgery at the same level and by 1.9-fold for BMI 30-34 and >35 in comparison with BMI 26-29, respectively. Postoperative deep wound infection was increased by 2.39-fold after DT than without. Significance in outcomes between patients with/without DT was not found. The invasiveness index explained 48% of the variation in blood loss and 51% of the variation in surgery duration.

CONCLUSIONS

The rate of incidental DT during decompression for LSS with and without fusion in ≥3 levels was associated with BMI and previous surgery at the same spinal level. Invasivness (SII) is valid rather for variables proper to surgery such as bledding and Op-time but no with incidence for DT and subsequent CSF-leackage.

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.

The degree of invasiveness has no influence on the rate of incidental durotomies in surgery for lumbar spinal canal stenosis: data from the German spine registry

BACKGROUND

Risk factors for incidental durotomies are good documented by some authors who consider the degree of invasiveness as a direct risk factor on this serious complication. We compared the rate of incidental durotomies and its dependence from the degree of invasiveness.

METHODS

The German Spine Registry could document 6016 surgeries for lumbar spinal canal stenosis, N.=2539 microsurgical decompression, and N.=2371 open decompression with stabilization.

RESULTS

Both groups were identical concerning age and sex of patients, mean age: 77.1±1.60; females: 58%; males: 32%. There were 410 incidental durotomies, group 1: 209 (8.23%); group 2: 201 (8.47%). This difference is statistically not relevant (P=0,75). A surgical therapy is documented in 345 (84%) cases, suture with/without fibrin glue: group 1=162 and group 2=183. Fifty-nine patients had a persistent fistula that needed treatment with a lumbar drain, group 1: N.=30; and group 2: N.=29.

CONCLUSIONS

The groups decompression vs. decompression plus fusion are statistically comparable. Although the stabilization with instrumentation is a more invasive procedure with longer operation times, trauma tissue and blood loss - in comparison with microsurgical decompression - showed no difference in the rate of incidental durotomies.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Conventional JOA score for cervical myelopathy has a rater's bias -In comparison with JOACMEQ

BACKGROUND

The JOA (Japan Orthopaedic Association) score has been a standard outcome measure to evaluate cervical myelopathy in Japan. Despite its reliability and convenience, there can be a rating bias in the JOA score. The current study was conducted to delineate the rater's bias of the JOA score by comparing it with a new objective outcome measure.

METHODS

Two hundred and thirty four operative candidates with cervical myelopathy were included in the study. The patients were divided into four groups according to the surgeon (92 patients in group A, 60 patients in group B, 38 patients in group C and 44 patients in group D). Each patient's preoperative JOA score was exclusively recorded by the surgeon himself, while JOACMEQ (Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire) was recorded by each patient. Disease severity, the most important prognostic factor, was equalized between patient groups by a special statistical method called inverse-probability weighting (IPW). To define similarity of the two groups, Cohen's d was used.

RESULTS

After the adjustment, the differences of the JOA score were only 0.1 between groups A and D and 0 between groups B and C. The values of Cohen's d were also very small both between groups A and D (3%), and between groups B and C (0.3%). The averaged JOA scores of groups A and D were higher by 0.4-0.8 than those of groups B and C, while the averaged JOA scores were almost the same both between groups A and D, and between groups B and C. Surgeons A and D had the same tendency to give higher JOA scores than surgeons B and C did.

CONCLUSIONS

The current study confirmed there is a definite rater's bias in the JOA score. JOACMEQ is to be applied as a more reliable outcome measure to evaluate myelopathy patients.

A new parallel closing mechanism for the laminectomy rongeur makes it significantly more precise: a biomechanical and mechanical comparison study

PURPOSE

To prove that a modified closing mechanism of the rongeur gives better precision compared to the old Kerrison rongeur.

METHODS

Forty persons from the departments of orthopaedic surgery, urology and neurosurgery (35 orthopaedic, 2 urology and 3 neurosurgery) took part in the study. All participants were asked to punch ten times in a first step with either the old Kerrison rongeur with the scissors-like handle or the modified punch with a new parallel closing mechanism. In a second step, they punched 10 times with the other instrument. Shaft movement in three dimensions was measured with a stereoscopic, contactless, full-field digital image correlation system.

RESULTS

The new rongeur is significantly more precise with less movement in all three dimensions. The mechanical model of the new rongeur shows that the momentum needed to keep the tip at the initial position changes only minimally during the closing act on the new model.

CONCLUSION

The new rongeur is more precise compared to the old Kerrison model. It is more robust against changes in the direction of the finger forces and may reduce soreness, fatigue and CTS in spine surgeons.

LEVEL OF EVIDENCE

Not applicable: technical study.