The impact of hypertension on the occurrence of postoperative spinal epidural hematoma following single level microscopic posterior lumbar decompression surgery in a single institute

Patient-reported Outcome After Surgical Evacuation of Postoperative Spinal Epidural Hematomas at One-year Follow-up

STUDY DESIGN

Retrospective analysis of prospectively collected data from the National Swedish Spine Register (Swespine).

OBJECTIVE

The objective of this study was to evaluate the effects of symptomatic spinal epidural hematoma (SSEH) requiring reoperation on one-year patient-reported outcome measures (PROMs) in a large cohort of patients treated surgically for lumbar spinal stenosis.

SUMMARY OF BACKGROUND DATA

Studies exploring the outcomes of reoperations after SSEH are scarce and often lack validated outcome measures. As SSEH is considered a serious complication, understanding of the outcome after hematoma evacuation is important.

MATERIALS AND METHODS

After retrieving data from 2007 to 2017 from Swespine, we included all patients with lumbar spinal stenosis without concomitant spondylolisthesis who were treated surgically with decompression without fusion. Patients with evacuated SSEH were identified in the registry. Back/leg pain numerical rating scales (NRSs), the Oswestry Disability Index (ODI), and EuroQol Visual Analogue Scale were used for the outcome assessment. PROMs before and one year after decompression surgery were compared between evacuated patients and all other patients. Multivariate linear regression was performed to determine whether hematoma evacuation predicted inferior one-year PROM scores.

RESULTS

A total of 113 patients with an evacuated SSEH were compared with 19527 patients with no evacuation. One-year after decompression surgery, both groups showed significant improvement in all PROMs. When comparing the two groups' one-year improvement, there were no significant differences in any PROM. The proportion of patients achieving the minimum important change was not significantly different for any PROM. Multivariate linear regression found that hematoma evacuation significantly predicted inferior one-year ODI (β=4.35, P =0.043), but it was not a significant predictor of inferior NRS Back (β=0.50, P =0.105), NRS Leg (β=0.41, P =0.221), or EuroQol Visual Analogue Scale (β=-1.97, P =0.470).

CONCLUSIONS

A surgically evacuated SSEH does not affect the outcome in terms of back/leg pain or health-related quality of life. Commonly used PROM surveys may not capture neurological deficits associated with SSEH.

Evaluation of the learning curve and complications in unilateral biportal endoscopic transforaminal lumbar interbody fusion: cumulative sum analysis and risk-adjusted cumulative sum analysis

PURPOSE

To evaluate the learning curve and complications in unilateral biportal endoscopic transforaminal lumbar interbody fusion (ULIF) using the Cumulative Sum (CUSUM) analysis and Risk-adjusted Cumulative Sum (RA-CUSUM) analysis.

METHODS

This study retrospectively analyzed 184 consecutive patients who received ULIF in our hospital, including 104 males and 80 females. CUSUM analysis and RA-CUSUM analysis were used to evaluate the learning curve of ULIF based on the operation time and surgical failure rate, respectively. All postoperative complications were defined as surgical failure. Variables of different phases were compared based on the learning curve.

RESULTS

The CUSUM analysis showed the cutoff point for ULIF was 29 cases, and the RA-CUSUM analysis showed the cutoff point for ULIF was 41 cases. Operating time and hospital stay were significantly decreased as the learning curve progressed (P < 0.05). Visual analogue score (VAS) and Oswestry disability index (ODI) at the last follow-up were significantly lower than preoperatively. At the last follow-up, a total of 171 patients reached intervertebral fusion, with a fusion rate of 92.9% (171/184). A total of eleven complications were observed, and RA-CUSUM analysis showed that the incidence of complications in the early phase was 17.07% and in the late phase was 2.6%, with a significant difference (P < 0.05).

CONCLUSION

ULIF is an effective minimally invasive lumbar fusion surgical technique. But a learning curve of at least 29 cases will be required to master ULIF, while 41 cases will be required to achieve a stable surgical success rate.

Why does such a cyst appear after unilateral biportal endoscopy surgery: A case report and literature review

BACKGROUND

Unilateral biportal endoscopy (UBE) has been widely and skillfully used in the treatment of lumbar disc herniation and spinal canal stenosis. UBE surgery also brings some complications, such as dural tear, epidural hematoma, residual nucleus pulposus, etc. And we found a rare case of arachnoid cyst after UBE.

CASE PRESENTATION

A 48 years old female who had a history of cholecystectomy, nephrolithiasis, hyperthyroidism, chronic atrophic gastritis, and colonic polyps with several years of low back pain and numbness in both lower limbs was found have arachnoid cyst 3 years after UBE operation. We hope that we can give a new aspect of complication after the UBE treatment in the future.

CONCLUSION

We believe that the postoperative hypertension and the lack of postoperative back muscle strength training and some personal factors are the possible reasons for the arachnoid cyst in this case.

Unilateral Neurological Deficit Due to Spinal Epidural Hematoma Following Midline-Sparing Spine Surgery: A Case Report

Symptomatic spinal epidural hematoma (SEH) is a rare but well-documented complication in spine surgery, often associated with risk factors such as abnormal coagulation parameters, low platelets, excessive epidural bleeding, and inadequate hemostasis. While bilateral SEH is frequently described in the literature, unilateral SEH following spine surgery is seldom reported. We present a unique case of a unilateral neurological deficit resulting from an SEH following midline-sparing spine surgery due to unilateral drain placement in an 80-year-old male patient without comorbidities and normal coagulation parameters. Subsequent evacuation of the hematoma was done leading to gradual recovery of neurology. This emphasizes the importance of bilateral drain placement in such midline-sparing spine surgeries. This report underscores the significance of early SEH diagnosis and intervention, providing valuable insights into preventive measures and the need for a high index of suspicion in managing this potentially debilitating complication.

Systemic Hypertension and Postoperative Symptomatic Spinal Epidural Hematoma: A Scoping Review

Postoperative symptomatic spinal epidural hematoma (PSSEH) is a serious complication of spinal surgery that is associated with significant morbidity. Studies suggest that hypertension is a risk factor for the development of PSSEH. The aim of this review was to evaluate the literature reporting associations between hypertension and PSSEH. A comprehensive literature search was conducted using the MEDLINE/PubMed, Embase, and Cochrane Library databases to identify studies that investigated PSSEH and reported data on preoperative hypertension status and/or perioperative blood pressure (BP). Eighteen studies were identified for inclusion in the review. Observational data suggested that uncontrolled/untreated preoperative hypertension, extubation-related increases in systolic BP, and elevated postoperative systolic BP were associated with an increased risk of PSSEH. The overall quality of evidence was low because of the retrospective nature of the studies, heterogeneity, and lack of precision in reporting. Despite the limitations of the current evidence, our findings could be important in establishing preoperative BP targets for elective spine surgery and inform perioperative clinical decision-making, while allowing consideration of risk factors for PSSEH. Well-controlled studies are required to investigate further the relationship between BP and PSSEH.

Risk factors of epidural hematoma in patients undergoing spinal surgery: a meta-analysis of 29 cohort studies

OBJECTIVE

The authors conducted this meta-analysis to identify risk factors for spinal epidural haematoma (SEH) among patients following spinal surgery.

METHODS

The authors systematically searched Pub: Med, Embase, and the Cochrane Library for articles that reported risk factors associated with the development of SEH in patients undergoing spinal surgery from inception to 2 July 2022. The pooled odds ratio (OR) was estimated using a random-effects model for each investigated factor. The evidence of observational studies was classified as high quality (Class I), moderate quality (Class II or III) and low quality (Class IV) based on sample size, Egger's P value and between-study heterogeneity. In addition, subgroup analyses stratified by study baseline characteristics and leave-one-out sensitivity analyses were performed to explore the potential sources of heterogeneity and the stability of the results.

RESULTS

Of 21 791 articles screened, 29 unique cohort studies comprising 150 252 patients were included in the data synthesis. Studies with high-quality evidence showed that older patients (≥60 years) (OR, 1.35; 95% CI, 1.03-1.77) were at higher risk for SEH. Studies with moderate-quality evidence suggested that patients with a BMI greater than or equal to 25 kg/m² (OR, 1.39; 95% CI, 1.10-1.76), hypertension (OR, 1.67; 95% CI, 1.28-2.17), and diabetes (OR, 1.25; 95% CI, 1.01-1.55) and those undergoing revision surgery (OR, 1.92; 95% CI, 1.15-3.25) and multilevel procedures (OR, 5.20; 95% CI, 2.89-9.37) were at higher risk for SEH. Meta-analysis revealed no association between tobacco use, operative time, anticoagulant use or American Society of Anesthesiologists (ASA) classification and SEH.

CONCLUSIONS

Obvious risk factors for SEH include four patient-related risk factors, including older age, obesity, hypertension and diabetes, and two surgery-related risk factors, including revision surgery and multilevel procedures. These findings, however, must be interpreted with caution because most of these risk factors had small effect sizes. Nonetheless, they may help clinicians identify high-risk patients to improve prognosis.

Postoperative Spinal Hematoma and Seroma

Fluid collections after spine surgery are rare complications, although potentially grave, and may be broadly grouped into two major categories. Symptomatic postoperative epidural hematomas have some known risk factors and can present with a widely variable profile of signs and symptoms. Treatment involves emergent surgical evacuation to reduce the risk of permanent neurologic deficit. Postoperative seroma may lead to disruption of wound healing and deep infection and has been associated with the use of recombinant human bone mineral protein. These diagnoses may present diagnostic challenges; thorough understanding of the involved pathophysiology, meticulous clinical evaluation, and radiographic interpretation are critical to appropriate management and optimal outcome.

Severe Symptomatic Epidural Hematoma Following Percutaneous Endoscopic Unilateral Laminectomy for Bilateral Decompression (Endo-ULBD)-Series Report and Management Strategies

OBJECTIVES

Severe symptomatic epidural hematoma (SSEH) is one of the most severe complications following percutaneous endoscopic unilateral laminectomy for bilateral decompression (Endo-ULBD). Considering that this technique has been performed for a short time, no detailed reports have been recently published. Thus, it is critical to gain a better understanding of SSEH occurring in its postoperative period with regard to its incidence, possible causes, outcome, etc., in order to identify relevant management strategies.

METHODS

Patients with spinal stenosis who had undergone Endo-ULBD in our department from May 2019 to May 2022 were retrospectively analyzed. Of which, patients with postoperative epidural hematoma were followed-up. The preoperative and postoperative physical conditions of each patient were recorded, and the information related to hematoma removal surgery was recorded in detail. Clinical outcomes were assessed using the visual analogue scale (VAS) and Oswestry disability index (ODI), and the results were classified into "excellent," "good," "fair," or "poor" based on the modified MacNab criteria. The incidence of hematoma with different factors was calculated, and a bar graph was used to compare the difference of the indexes related to hematoma removal between cases, and a line graph was used to reflect the trend of the outcome of each patient within 6 months to evaluate the effect of the treatment.

RESULTS

A total of 461 patients with spinal stenosis who underwent Endo-ULBD were enrolled in the study. SSEH occurred in four cases, with an incidence rate of 0.87% (4/461). All these four patients underwent decompression of multiple segments, and three of them had a history of hypertension comorbid with diabetes. Notably, one patient had a past history of hypertension and coronary artery disease and was on postoperative low molecular heparin due to lower extremity venous thrombosis. According to the conditions of the four patients, three types of treatment were used. And with timely treatment, all patients recovered well.

CONCLUSION

Despite being a minimally invasive technique, postoperative epidural hematoma remains a severe complication of Endo-ULBD. Therefore, during percutaneous endoscopic surgery, it is essential to enhance the comprehensive perioperative management of patients with Endo-ULBD. Signs related to postoperative hematoma must be recognized and promptly managed. If necessary, satisfactory results can be achieved by using percutaneous endoscopy along the original surgical channel to remove the hematoma.

The Influence of Systolic Blood Pressure at the Time of Extubation on the Development of Postoperative Spinal Epidural Hematoma

Background

The most common cause of neurological complications after a biportal endoscopic spine surgery (BESS) is postoperative spinal epidural hematomas (POSEH). The objective of this study was to determine the influence of systolic blood pressure at extubation (e-SBP) on POSEH.

Methods

A total of 352 patients who underwent single-level decompression surgery including laminectomy and/or discectomy with BESS under the diagnosis of spinal stenosis and herniated nucleus pulposus between August 1, 2018, and June 30, 2021, were reviewed retrospectively. The patients were divided into two, a POSEH group and a normal group without POSEH (no neurological complication). The e-SBP, demographic factors, and the preoperative and intraoperative factors suspected to influence the POSEH were analyzed. The e-SBP was converted to a categorical variable by the threshold level that was decided by maximum area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis. Antiplatelet drugs (APDs) were taken in 21 patients (6.0%), discontinued in 24 patients (6.8%), and not taken in 307 patients (87.2%). Tranexamic acid (TXA) was used in 292 patients (83.0%) in the perioperative period.

Results

Of the 352 patients, 18 patients (5.1%) underwent revision surgery for the removal of POSEH. The POSEH and normal groups were homogenous in age, sex, diagnosis, operation segments, operation time, and lab findings that were related to blood clotting, whereas there were differences in e-SBP (163.7 ± 15.7 mmHg in POSEH group and 154.1 ± 18.3 mmHg in normal group), APD (4 takers, 2 stoppers, 12 non-takers in POSEH group and 16 takers, 22 stoppers, 296 non-takers in normal group), and TXA (12 use, 6 not use in POSEH group and 280 use, 54 not use in normal group) in single variable analysis. The highest AUC in the ROC curve analysis was 0.652 for 170 mmHg e-SBP (p < 0.05). There were 94 patients in the high e-SBP group (≥ 170 mmHg) and 258 patients in the low e-SBP group. In multivariable logistic regression analysis, only high e-SBP was a significant risk factor for POSEH (p = 0.013; odds ratio, 3.434).

Conclusions

High e-SBP (≥ 170 mmHg) can influence the development of POSEH in biportal endoscopic spine surgery.

Characteristics of the Patients with Poor Clinical Outcomes After Symptomatic Postoperative Lumbar Epidural Hematoma

OBJECTIVE

Symptomatic postoperative lumbar epidural hematoma (PLEH) may lead to poor outcomes even after evacuation. This study aimed to verify the short-term clinical outcomes after the evacuation of PLEH and to clarify the characteristics of the patients with poor postoperative outcomes.

METHODS

Twenty-five patients (average age; 70.4 years) underwent PLEH evacuation after lumbar spine surgery. The mean follow-up period was 12.0 (range 3-37) months. Pre and postoperative Japanese Orthopedic Association scores and visual analog scale (VAS) of low back pain (LBP), leg pain, and leg numbness were retrospectively collected. The dural sac cross-sectional area at the most compressed level was measured on magnetic resonance imaging. The patients were classified into 2 groups: poor outcome group (P group) had less than 50% of Japanese Orthopedic Associationrecovery rate and good group (G group) with 50% or more recovery rate.

RESULTS

The rate of delayed evacuation (over 24 hours of onset) was significantly higher in P group than in G group (P = 0.027). There was no significant difference in dural sac cross-sectional areabetween the 2 groups (P = 0.438). VAS of LBP, leg pain, and leg numbness in G group significantly improved postoperatively. Although VAS of LBP and leg pain in P group significantly improved postoperatively, there was no significant difference between the pre and postoperative VAS of leg numbness.

CONCLUSIONS

Delayed evacuation of PLEH can lead to poor postoperative outcomes after lumbar spine surgery. Moreover, patients with poor outcomes remained with postoperative leg numbness. Early evacuation of symptomatic PLEH is key to avoid poor outcomes and persistent leg numbness.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Incidence of postoperative symptomatic spinal epidural hematoma requiring surgical evacuation: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to determine the incidence of symptomatic spinal epidural hematoma (SSEH) following spine surgery.

METHODS

We systematically searched for all relevant articles that mentioned the incidence of SSEH following the spine surgery published in the PubMed, Embase, and Cochrane Library databases through March 2022 and manually searched the reference lists of included studies. The Newcastle-Ottawa quality assessment scale (NOS) was used to assess the quality of the included studies. A fixed-effects or random-effects model was performed to calculate the pooled incidence of the totality and subgroups based on the heterogeneity. The potential publication bias was assessed by Egger's linear regression and a funnel plot. Sensitivity analysis was also conducted.

RESULTS

A total of 40 studies were included in our meta-analysis based on our inclusion and exclusion criteria. The overall pooled incidence of SSEH was 0.52% (95% CI 0.004-0.007). In the subgroup analysis, the pooled incidence of SSEH in males and females was 0.86% (95% CI 0.004-0.023) and 0.68% (95% CI 0.003-0.017). Among the different indications, a higher incidence (2.9%, 95% CI 0.006-0.084) was found in patients with deformity than degeneration (1.12%, 95% CI 0.006-0.020) and tumor (0.30%, 95% CI 0.006-0.084). For different surgical sites, the incidences of SSEH in cervical, thoracic and lumbar spine were 0.32% (95% CI 0.002-0.005), 0.84% (95% CI 0.004-0.017) and 0.63% (95% CI 0.004-0.010), respectively. The incidences of SSEH in anterior and posterior approach were 0.24% (95% CI 0.001-0.006) and 0.70% (95% CI 0.004-0.011), respectively. The pooled incidence of SSEH was five times higher with minimally invasive surgery (1.94%, 95% CI 0.009-0.043) than with open surgery (0.42%, 95% CI 0.003-0.006). Delayed onset of SSEH had a lower incidence of 0.16% (95% CI 0.001-0.002) than early onset. There were no significant variations in the incidence of SSEH between patients who received perioperative anticoagulation therapy and those who did not or did not report getting chemopreventive therapy (0.44%, 95% CI 0.006-0.084 versus 0.42%, 95% CI 0.003-0.006).

CONCLUSION

We evaluated the overall incidence proportion of SSEH after spine surgery and performed stratified analysis, including sex, surgical indication, site, approach, minimally invasive surgery, and delayed onset of SSEH. Our research would be helpful for patients to be accurately informed of their risk and for spinal surgeons to estimate the probability of SSEH after spine surgery.

Increased Surgical Experience in Microendoscopic Spinal Surgery Can Reduce Development of Postoperative Spinal Epidural Hematoma and Improve the Clinical Outcomes

No reports have previously evaluated the association between surgical technique and the incidence of postoperative spinal epidural hematoma (PSEH) following microendoscopic decompression surgery (MED). This study aimed to evaluate the association between the development of radiographic PSEH (rPSEH) following MED and microendoscopic surgical experience and postoperative clinical outcomes related to the quality of life (QoL). This retrospective cohort study included 3922 patients who had undergone MED performed by a single surgeon. rPSEH was defined as a hematoma that was identified via routine magnetic resonance images performed 3−4 days postoperatively. Patients were divided into rPSEH and control groups to identify the risk factor of rPSEH and assess clinical outcomes. In the multivariate analysis, age (p = 0.002), surgical experience (p = 0.003), surgical time (p = 0.038), multilevel decompression (p < 0.001), and diagnosis (p = 0.004) were identified as independent variables associated with rPSEH. Moreover, in mixed-effect models, the rPSEH group showed less improvement in Oswestry Disability Index (p = 0.014) than the control group. In conclusion, the surgical experience was identified as a risk factor for rPSEH that could lead to poor QoL. The sharing of microendoscopic surgical techniques among surgeons may reduce rPSEH incidence and improve patients’ QoL.

Symptomatic Postoperative Epidural Hematoma in the Lumbar Spine

A symptomatic postoperative epidural hematoma (SPEH) in the lumbar spine is a complication with variable presentation and the potential to rapidly cause an irrecoverable neurological injury. Significant heterogeneity exists among current case series reporting SPEH in the literature. This review attempts to clarify the known incidence, risk factors, and management pearls. Currently, literature does not support the efficacy of subfascial drains in reducing the incidence of SPEHs and possibly suggests that medication for thromboembolism prophylaxis may increase risk. Acute back pain and progressing lower extremity motor weakness are the most common presenting symptoms of SPEH. Magnetic resonance imaging is the mainstay of diagnostic imaging necessary to confirm the diagnosis, but if not acutely available, an immediate return to the operative theater for exploration without advanced imaging is justified. Treatment of a SPEH consists of emergent hematoma evacuation as a delay in repeat surgery has a deleterious effect on neurological recovery. Outcomes are poorly defined, though a significant portion of patients will have lasting neurological impairments even when appropriately recognized and managed.

The Influence of High Blood Pressure on Developing Symptomatic Lumbar Epidural Hematoma after Posterior Lumbar Spinal Fusion Surgery: Clinical Data Warehouse Analysis

Background: Determining the risk factors for symptomatic lumbar epidural hematoma (SLEH) is important for preventing postoperative SLEH. However, the relationship between blood pressure and SLEH is still debatable. The purpose of our study was to determine the risk factors for postoperative SLEH, to assess the influence of high blood pressure on developing SLEH after posterior lumbar spinal fusion surgery, and to evaluate the usefulness of big data analysis utilizing a clinical data warehouse (CDW). Methods: The clinical data of patients who had undergone posterior lumbar spinal fusion surgery were acquired from the CDW of Hallym University Medical Center. The acquired clinical data were compared between patients without postoperative SLEH and with postoperative SLEH. Results: Postoperative SLEH that required hematoma evacuation surgery within 72 h after posterior lumbar spinal fusion surgery occurred in 17 (1.3%) of 1313 patients. According to the multivariate logistic regression analysis, the risk factors for postoperative SLEH are platelet count difference (OR 1.28, p = 0.03), postoperative international normalized ratio (INR) difference (OR 31.4, p = 0.028), and postoperative systolic blood pressure (SBP) difference (≥10 mmHg) (OR 1.68, p = 0.048). An increase in postoperative SBP (OR 1.68, p = 0.048) had a statistically significant influence on the occurrence of postoperative SLEH. Conclusions: Big data analysis utilizing a CDW could be useful for extending our knowledge of the risk factors for postoperative SLEH and preventing postoperative SLEH after posterior lumbar spinal fusion surgery.

Incidence and Risk Factors for Symptomatic Spinal Epidural Hematoma Following Posterior Thoracic Spinal Surgery in a Single Institute

STUDY DESIGN

Case-control study.

OBJECTIVES

To investigate the incidence of symptomatic spinal epidural hematoma (SSEH) and recognize its risk factors in a cohort of patients undergoing posterior thoracic surgery in isolation.

METHODS

From January 2010 to December 2019, patients who developed SSEH after posterior thoracic surgery and underwent hematoma evacuation were enrolled. For each SSEH patient, 2 or 3 controls who did not develop SSEH and underwent the same procedures with similar complexity at the same section of the thoracic spine in the same period were collected. The preoperative and intraoperative factors, blood pressure-related factors and radiographic parameters were collected to identify possible risk factors by comparing between the 2 groups.

RESULTS

A total of 24 of 1612 patients (1.49%) were identified as having SSEH after thoracic spinal surgery. Compared to the control group (53 patients), SSEH patients had significant differences in the APTT (p = 0.028), INR (p = 0.009), ratio of previous spinal surgery (p = 0.012), ratio of cerebrospinal fluid leakage (p = 0.004), thoracic kyphosis (p<0.05), local kyphosis angle (p<0.05), epidural fat ratio at T7 (p = 0.003), occupying ratio of the cross-sectional area (p<0.05) and spinal epidural venous plexus grade (p<0.05). Multiple logistic regression analysis revealed 3 risk factors for SSEH: cerebrospinal fluid leakage, the local kyphosis angle (>8.77°) and the occupying ratio of the cross-sectional area (>49.58%).

CONCLUSIONS

The incidence of SSEH was 1.49% in posterior thoracic spinal surgeries. Large local kyphosis angle (>8.77°), high occupying ratio of cross-sectional area (>49.58%) and cerebrospinal fluid leakage were identified as risk factors for SSEH.

Risk Factors for Incidence of Postoperative Spinal Epidural Hematoma Following Multilevel Microendoscopic Laminectomy

Introduction

Due to the narrow portal of entry, microendoscopic laminectomy (MEL) is associated with a risk of postoperative spinal epidural hematoma (POSEH). This risk might be higher when performing multiple-level (m-) MEL. The purpose of this study is to clarify the incidence rate of POSEH following single-level (s-) and m-MEL by each interlaminar level and identify the risk factors for POSEH following m-MEL.

Methods

A total of 379 patients underwent MEL of the lumbar spine (s-MEL, n=141; m-MEL, n=238). We determined the incidence of POSEH following s-MEL and m-MEL by each interlaminar level. For m-MEL, we clarified the correlation between POSEH and possible risk factors, such as operative findings, the sequence of operated interlaminar levels, and the preoperative cross-sectional dural area (CSA) on magnetic resonance imaging.

Results

The incidence rate at L2/3 was significantly higher than that at L3/4 and L4/5. Patients who underwent L2/3 decompression at the end of the procedure showed a higher incidence of POSEH at the L2/3 level. Preoperative spinal stenosis was associated with POSEH at the L2/3 level, and CSA of 56 mm² was a predictive factor for POSEH. Logistic regression analysis revealed that both were significant risk factors.

Conclusions

In patients undergoing m-MEL, the incidence of POSEH is highest at the L2/3 level, and treatment of the L2/3 level at the end of the procedure and the presence of spinal stenosis are risk factors for POSEH.

Postoperative Epidural Hematoma

Symptomatic postoperative epidural hematomas are rare, with an incidence of 0.10% to 0.69%. Risk factors have varied in the literature, but multiple studies have reported advanced age, preoperative or postoperative coagulopathy, and multilevel laminectomy as risk factors for hematoma. The role of pharmacologic anticoagulation after spine surgery remains unclear, but multiple studies suggest it can be done safely with a low risk of epidural hematoma. Prophylactic suction drains have not been found to lower hematoma incidence. Most symptomatic postoperative epidural hematomas present within the first 24 to 48 hours after surgery but can present later. Diagnosis of a symptomatic hematoma requires correlation of clinical signs and symptoms with a compressive hematoma on MRI. Patients will usually first complain of a marked increase in axial pain, followed by radicular symptoms in the extremities, followed by motor weakness and sphincter dysfunction. An MRI should be obtained emergently, and if it confirms a compressive hematoma, surgical evacuation should be carried out as quickly as possible. The prognosis for neurologic improvement after evacuation depends on the time delay and the degree of neurologic impairment before evacuation.

Efficacy and Complications of Unilateral Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis: A Meta-Analysis and Systematic Review

OBJECTIVE

As an emerging minimally invasive endoscopic technique, unilateral biportal endoscopic spinal surgery (UBESS) has the advantages of flexibility, a wide and clear field of view, and less soft tissue damage. However, the clinical evidence is insufficient and controversy exists regarding UBESS for the treatment of lumbar spinal stenosis (LSS). In the present meta-analysis, we investigated the clinical efficacy and complications of UBESS for the treatment of LSS.

METHODS

The PubMed, Embase, Web of Science, and Cochrane Library databases were searched through to June 1, 2021 to identify all reported studies on UBESS for LSS. Only English-language studies with original reported data from ≥30 cases were considered for inclusion. The patient demographics, operative time, hospital stay, complications, visual analog scale (VAS) score, Oswestry disability index, and Macnab criteria were extracted. Quality assessment was performed using the Cochrane collaboration tool for randomized controlled trials and the Newcastle-Ottawa scale for retrospective studies. A meta-analysis was performed using a random or fixed effect model according to the heterogeneity.

RESULTS

Thirteen studies with 586 patients and 607 operation levels were included. The mean single-level operative time, hospital stay, and follow-up duration were 61.10 minutes, 2.32 days, and 14.7 months, respectively. At the final follow-up visit, the mean VAS score for leg pain had decreased from 7.23 preoperatively to 1.83 postoperatively, the mean VAS score for back pain had decreased from 6.30 to 1.95, and the mean Oswestry disability index had significantly improved from 56.99 to 17.83. The average satisfied outcome (excellent or good using the Macnab criteria) was 86%. The overall complication rate was 5%, and the most common complication was a dural tear, with an incidence of 2%, followed by epidural hematoma with an incidence of 1%. The remaining complications were nerve root injury, inadequate decompression, and postoperative headache.

CONCLUSIONS

From the available clinical results and experience from reported studies, UBESS for LSS is a feasible and effective approach and a worthwhile choice for clinicians. However, the complications associated with the procedure should also be seriously considered.

Impact of acetylsalicylic acid (ASA) on postoperative hemorrhage in spinal lumbar surgery: Should preoperative ASA be discontinued for elective surgery?

OBJECTIVE

The application of acetylsalicylic acid (ASA) represents high evidence in the aging society due to primary and secondary prevention in cardiovascular disease and stroke. However, this presents a challenge for neurosurgeons in terms of preoperative and postoperative management of care. This study aimed to analyze the risk of bleeding by applying ASA before lumbar spinal surgery.

METHODS

Retrospective analysis of medical records of 3051 patients was performed from 2008 to 2018 who underwent lumbar surgery at our institution. The risk of postoperative hemorrhage was compared in patients treated with ASA versus patients without ASA treatment. Additionally, the relationship between discontinuation of ASA preoperatively (≥7 days) or no previous history of ASA versus continuation with ASA (<7 days) on postoperative hemorrhage was analyzed.

RESULTS

Postoperative hemorrhagic were observed in 2.1% (n = 63) of all lumbar operations. In 421 patients, the effect of ASA (<7 days) was still persistent at the time of surgery (ASA impact group). Of these, 12 (2.85%) patients had a hemorrhage. No significant differences were found in comparison to the No ASA impact group (p = 0.272). Sex (p = 0.003), hypertension (p = 0.015), recurrent surgery (p = 0.001) and use of hemostatic agents (p = 0.023) had a significant impact on postoperative hemorrhage.

CONCLUSION

The continuation of ASA medication is not associated with increased risk of postoperative hemorrhage after spinal surgery. However, sex, hypertension, recurrent surgery and the use of hemostatic agents under continued ASA treatment were found to be associated with an increased risk of hemorrhage.

Identifying risks factors in thoracolumbar anterior fusion surgery through predictive analytics in a nationally representative inpatient sample

PURPOSE

Anterior thoracolumbar (TL) surgical approaches provide more direct trajectories compared to posterior approaches. Proper patient selection is key in identifying populations that may benefit from anterior TL fusion. Here, we utilize predictive analytics to identify risk factors in anterior TL fusion in patients with trauma and deformity.

METHODS

In this retrospective cohort study of patients receiving anterior TL fusion (between and including T12/L1), population-based regression models were developed to identify risk factors using the National Readmission Database 2016-2017. Readmissions were analyzed at 30- and 90-day intervals. Risk factors included hypertension, obesity, malnutrition, smoking, alcohol use, long-term opioid use, and frailty. Multivariate regression models were developed to determine the influence of each risk factor on complication rates.

RESULTS

A total of 265 and 375 patients were identified for the scoliosis and burst fracture cohorts, respectively. In patients with scoliosis, alcohol use was found to increase the length of stay (LOS) (p = 0.00061) and all-payer inpatient cost following surgery (p = 0.014), and frailty was found to increase the inpatient LOS (p = 0.0045). In patients with burst fractures, malnutrition was found to increase the LOS (p < 0.0001) and all-payer cost (p < 0.0001), obesity was found to increase the all-payer cost (p = 0.012), and frailty was found to increase the all-payer cost (p = 0.031) and LOS (p < 0.0001).

DISCUSSION

Patient-specific risk factors in anterior TL fusion surgery significantly influence complication rates. An understanding of relevant risk factors before surgery may facilitate preoperative patient selection and postoperative patient triage and risk categorization.

Which Criterion for Wound Drain Removal is Better Following Posterior 1-Level or 2-Level Lumbar Fusion With Instrumentation: Time Driven or Output Driven?

STUDY DESIGN

Case-control study.

OBJECTIVES

To compare the outcomes of 2 different criteria (time driven and output driven) for wound drain removal and identify which one is better.

METHODS

743 patients who underwent posterior lumbar fusion with instrumentation involving 1 or 2 motion segments were enrolled in this study. Based on the different criteria for drain removal, the patients were divided into 2 groups. The drains were discontinued by time driven (postoperative day 2) in group I and output driven (<50 ml per day) in group II. Demographic characteristics, perioperative parameters and clinical outcomes were compared between the 2 groups.

RESULTS

The demographic characteristics in both groups were comparable. The postoperative drain output, total blood loss, postoperative timing of ambulation, and postoperative duration of hospital stay in group I were lower than those in group II (P < 0.001). There was a higher proportion of patients requiring postoperative blood transfusion in group II, but not to a level of statistical significance (P = 0.054). There was no statistical significant difference in the incidence of surgical site infection (SSI) or symptomatic spinal epidural hematoma (SEH) between the 2 groups (P > 0.05).

CONCLUSIONS

This study reveals that there are more benefits of wound drain removal by time driven than that by output driven for patients undergoing posterior 1-level or 2-level lumbar fusion with instrumentation, including less postoperative drain output, less total blood loss, earlier postoperative timing of ambulation and less postoperative duration of hospital stay without increasing the incidence of postoperative SSI or symptomatic SEH.

Does prophylactic use of topical gelatin-thrombin matrix sealant affect postoperative drainage volume and hematoma formation following microendoscopic spine surgery? A randomized controlled trial

BACKGROUND CONTEXT

Microendoscopic spinal surgery has demonstrated efficacy and is increasingly utilized as a minimally invasive approach to neural decompression, but there is a theoretical concern that bleeding and postoperative epidural hematoma (PEH) may occur with increased frequency in a contained small surgical field. Hemostatic agents, such as topical gelatin-thrombin matrix sealant (TGTMS), are routinely used in spine surgery procedures, yet there has been no data on whether PEH is suppressed by these agents when administered in microendoscopic spine surgery.

PURPOSE

The purpose of this study was to investigate the effect of TGTMS on bleeding and PEH formation in lumbar micoroendoscopic surgery.

STUDY DESIGN

This is a randomized controlled trial (RCT) with additional prospective observational cohort.

PATIENT SAMPLE

Patients were registered from July 2017 to September 2018 and a hundred and three patients undergoing microendoscopic laminectomy for lumbar spinal stenosis at a single institution were enrolled in this study.

OUTCOME MEASURES

The primary outcome was the drainage volume within 48 hours after surgery. Secondary outcomes were the numerical rating scale (NRS) of leg pain on the second (NRS2) and seventh day (NRS7) after surgery and the hematoma area ratio (HAR) in horizontal images on magnetic resonance image (MRI).

METHODS

In the RCT, 41 cases that received TGTMS (F group) were compared with 41 control group cases (C group) that did not receive TGTMS at the end of the procedure. Drainage volume, NRS2, NRS7, and HAR on MRI were evaluated. Nineteen cases were excluded from the RCT (I group) due to difficulty of hemostasis during surgery and the intentional use of TGTMS for hemostasis. I group was compared with C group in the drainage volume and NRS of leg pain as a prospective observational study.

RESULTS

The RCT demonstrated no statistically significant difference in drainage volume between those receiving TGTMS (117.0±71.7; mean±standard deviation) and controls (125.0±127.0; p=.345). The NRS2 and NRS7 was 3.5±2.6 and 2.8±2.5 in the F group, respectively, and 3.1±2.6 and 2.1±2.3 in the C group, respectively. The HAR on MRI was 0.19±0.19 in the F group and 0.17±0.13 in the C group. There was no significant difference in postoperative leg pain and HAR (p=.644 for NRS2, p=.129 for NRS7, and p=.705 for HAR). In the secondary observational cohort, the drainage volume in the I group was 118.3±151.4, and NRS2 and NRS7 was 3.5±2.0 and 2.6±2.6, respectively. There were no statistically significant differences in drainage volume (p=.386) or postoperative NRS of leg pain between these two groups (p=.981 and .477 for NRS2 and NRS7, respectively).

CONCLUSIONS

The prophylactic use of TGTMS in patients undergoing microendoscopic laminotomy for lumbar spinal stenosis did not demonstrate any difference in postoperative bleeding or PEH. Nonetheless, for patients that had active bleeding that required the use of TGTMS, there was no evidence of difference in postoperative clinical outcomes relative to controls.

[Research progress in effect of obesity on the effectiveness of posterior lumbar fusion]

Objective

To review the effect of obesity on the effectiveness of posterior lumbar fusion in patients with lumbar degenerative diseases (LDD).

Methods

The related literature at home and abroad was extensively reviewed. And the difficulty of operation, risk of complications, and long-term effectiveness of posterior lumbar fusion for obese patients with LDD were summarized.

Results

Although some relevant literature suggest that the posterior lumbar fusion for obese patients is difficult and the risk of postoperative complications is high, the overall research results do not suggest that obesity is a risk factor for the implementation of posterior lumbar fusion. By assessing the physical condition of patients and strictly grasping the surgical indications, obese patients can obtain good surgical efficacy.

Conclusion

Posterior lumbar fusion is an effective method for the treatment of LDD in obese patients. However, relevant studies need to be completed to further evaluate the safety and efficacy of posterior lumbar fusion for obese patients.

Delayed Onset Postoperative Spinal Epidural Hematoma after Lumbar Spinal Surgery: Incidence, Risk Factors, and Clinical Outcomes

Background

Posterior spinal epidural haematoma (PSEH) often develops within 24 hours after surgery. On rare occasions, PSEH occurs after 3 days and up to two weeks and is classified as delayed-onset PSEH. Due to its rarity, previous studies have only described the clinical features, whereas risk factors have not been assessed.

Methods

Patients who developed PSEH requiring haematoma evacuation between December 2013 and January 2020 were included and divided into the early-onset (group A) and delayed-onset (group B) groups based on the time of symptom onset (>72 hours). For each PSEH patient, 3 controls (group C) who did not develop PSEH in the same period were randomly selected. Clinical features were compared among the three groups, and multiple logistic regression analysis was performed to identify the risk factors for groups A and B.

Results

Thirty-two patients (0.35%) were identified as having early-onset PSEH (occurring at 10.68 ± 11.5 h), and 15 (0.16%) patients had delayed-onset PSEH (occurring at 130.60 ± 61.78 h). When comparing groups A and B, group A showed a higher rate of multilevel procedures, lower drainage, lower APTT, and higher JOA score at discharge. Multiple logistic regression analysis identified multilevel procedures (OR: 5.62, 95% CI: 1.84-17.25), postoperative systolic blood pressure (SBP) (OR: 1.10, 95% CI: 1.06-1.15), and abnormal coagulation (OR: 5.68, 95% CI: 1.74-18.52) as independent risk factors for group A, whereas postoperative SBP (OR: 1.10, 95% CI: 1.04-1.16) and previous spinal surgery (OR: 4.74, 95% CI: 1.09-20.70) at the same level were risk factors for group B.

Conclusions

Our study revealed that the overall incidence of delayed-onset PSEH was 0.16% in posterior lumbar spinal surgery and that its risk was different from that of early-onset PSEH. If patients with such risk factors develop neurological deficits 3 days after initial surgery, surgeons should be aware of the possibility of delayed-onset PSEH.

Minimal invasive management of early revision after minimal invasive posterior lumbar fusion

BACKGROUND

Minimally invasive spine (MIS) fusion is an increasingly common procedure, with advantages over open approach in the form of minimal dissection and superior early clinical outcome. The frequency of complications is known, but the most appropriate surgical revision for this technique remains unclear.

HYPOTHESIS

The main hypothesis was that early revision surgery, for acute complications after MIS, was possible through mini-invasive approach.

METHODS

A retrospective study of patients undergoing MIS has been performed, with or without transforaminal interbody fusion (TLIF) using specific navigation and ancillary. All surgical revisions were done by minimally invasive approach. Preoperative and surgical data, as well as postoperative complications have been analyzed. The primary endpoint was clinical outcome obtained after surgical revision.

RESULTS

Data of 187 patients undergoing MIS procedure at 1-4 levels was analyzed. The rate of early revision (within one month) was 5.3%: 0.5% for infection, 1.6% for compressive hematoma, and 2.1% for misplaced screw. The use of intraoperative navigation decreased the frequency of screw misplacement from 4.5% to 1.4%. The rate of surgical revision was 7.8% for surgeons in their learning curve and 3.6% for experienced surgeons.

DISCUSSION

On these large series, MIS early revision rates were lower than previously reported for conventional fusions. Surgeon's experience in MIS procedures seems to be crucial to decrease revision and complications rates. Hemorrhagic complications led to multidisciplinary discussions and the establishment of a management protocol. Surgical revisions can be performed by minimally invasive techniques, regardless of the indication.

LEVEL OF EVIDENCE

IV, retrospective study.

Comparative Study Between Uniportal Full-Endoscopic Interlaminar and Tubular Approach in the Treatment of Lumbar Spinal Stenosis: A Pilot Study

STUDY DESIGN

Multicenter, prospective, randomized, and double-blinded study.

OBJECTIVES

To compare tubular and endoscopic interlaminar approach.

METHODS

Patients with lumbar spinal stenosis and neurogenic claudication of were randomized to tubular or endoscopic technique. Enrollment period was 12 months. Clinical follow up at 1, 3, 6 months after surgery with visual analogue scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) score. Radiologic evaluation with magnetic resonance pre- and postsurgery.

RESULTS

Twenty patients were enrolled: 10 in tubular approach (12 levels) and 10 in endoscopic approach (11 levels). The percentage of enlargement of the spinal canal was higher in endoscopic approach (202%) compared with tubular approach (189%) but was not statistically significant (P = .777). The enlargement of the dural sac was higher in endoscopic group (209%) compared with tubular group (203%) but no difference was found between the 2 groups (P = .628). A modest significant correlation was found between the percentage of spinal canal decompression and enlargement of the dural sac (r = 0.5, P = .023). Both groups reported a significant clinical improvement postsurgery. However, no significant association was found between the percentage of enlargement of the spinal canal or the dural sac and clinical improvement as determined by scales scores. Endoscopic group had lower intrasurgical bleeding (P < .001) and lower disability at 6 months of follow-up than tubular group (p=0.037).

CONCLUSIONS

In the treatment of lumbar spinal stenosis, endoscopic technique allows similar decompression of the spinal canal and the dural sac, lower intrasurgical bleeding, similar symptoms improvement, and lower disability at 6 months of follow-up, as compared with the tubular technique.

Decompressive Surgery for Lumbar Spinal Stenosis: WFNS Spine Committee Recommendations

Objective

Lumbar spine stenosis is a common disease with a prevalence progressively increasing due to the aging of the population. Despite many papers having been published over the last decades, there still remain many doubts regarding its natural history and appropriate treatment. To overcome these problems and reach some globally accepted recommendations, the World Federation of Neurosurgical Society Spine Committee organized a consensus conference on this topic. This paper describes recommendations about the efficacy of surgical decompression, the difference between surgical techniques, and complications of surgery.

Methods

World Federation of Neurosurgical Society Spine Committee aimed to standardize clinical practice worldwide as much as possible and held a 2-round consensus conference on lumbar spinal stenosis. A team of expert spine surgeons reviewed literature regarding surgical treatment from over the last 10 years, and then drafted and voted on some statements based on the presented literature.

Results

Ten statements were voted. The committee agreed on the effectiveness of surgical decompression in patients with moderate-to-severe symptoms or with neurologic deficits. There was no consensus on the best surgical technique and, in particular, about the equivalence of microscopic techniques and an open approach. Regarding complications, we agreed that the most frequent complications are incidental durotomy and general complications in the elderly.

Conclusions

Surgical decompression represents the treatment of choice for symptomatic lumbar spinal stenosis with a low complication rate. However, which surgical technique is the best is still under debate. Further studies with standardized outcome measures are needed to understand the real complication rate and frequency of different unwanted events.

Five-year Reoperation Rates and Causes for Reoperations Following Lumbar Microendoscopic Discectomy and Decompression

STUDY DESIGN

Retrospective study of prospectively collected outcome data.

OBJECTIVE

The aim of this study was to investigate reoperation cases and determine whether or not the experience period of a single surgeon was associated with the causes of reoperations following lumbar microendoscopic discectomy for disc herniation (MEDH) and microendoscopic decompression for spinal stenosis (MEDS).

SUMMARY OF BACKGROUND DATA

There have been few studies that investigated reoperation cases following MEDH and MEDS.

METHODS

Between June 2005 (first experience of MEDH) and September 2013, the same surgeon had been using MEDH and/or MEDS on 441 consecutive patients. The follow-up rate was 89.3%. The causes and rates of reoperations (RORs) were determined at 5 years after the initial operations. We also investigated the experience period of a single surgeon (EPS, interval between June 2005 and initial operation: median, 37 months).

RESULTS

The 5-year reoperation rate for all patients combined was 12.4% (49/394). The main causes for reoperations were recurrence of disc herniation (ROR, 7.01%) and increase of postoperative spondylolisthesis and/or instability (ROR, 9/394 = 2.28%); two of the nine cases were caused by excessive decompression, and the EPSs were 11 and 16 months. The other causes for reoperations were postoperative epidural hematoma (ROR, 0.76%; median EPS, 20 months), insufficient decompression (ROR, 0.25%; EPS, 17 months), and residual segmental scoliosis (ROR, 7.69%); two segmental scoliosis cases did not provide relief from sciatica, and therefore L4/5 transforaminal interbody fusions were performed.

CONCLUSION

Postoperative epidural hematoma and excessive or insufficient decompression were often observed in the initial series of patients as the causes for reoperations. We think that it is important to be aware of and prevent such potential problems in any initial series of patients, as there are limitations to any surgical indications for the use of microendoscopic decompression for degenerative segmental scoliosis because of original traction and/or kinking of nerve roots.

LEVEL OF EVIDENCE

4.

Incidence and Clinical Features of Postoperative Symptomatic Hematoma after Spine Surgery: A Multicenter Study of 45 Patients

Introduction

Symptomatic postoperative hematoma after spine surgery is a rare but serious complication. The objective of this study was to investigate the incidence and clinical features of symptomatic postoperative hematoma after spine surgery.

Methods

We retrospectively identified 10,680 patients who underwent spine surgery between 2002 and 2012 in nine hospitals. We reviewed the incidence of postoperative hematoma and its clinical features, including time before onset, main symptoms, and neurological outcomes.

Results

The overall incidence of symptomatic postoperative hematoma after spine surgery was 0.4% (45/10,680). Postoperative hematoma was more frequent after thoracic spine surgery than after cervical or lumbar surgery. The onset of postoperative hematoma occurred at an average of 2.6 days (range 0-14 days) postoperatively. The chief symptoms caused by postoperative hematoma after spine surgery were tetra/paraplegia in 30 patients, hemiplegia in eight patients, intractable pain in five patients, and airway dysfunction in two patients. Surgical evacuation of the spinal epidural hematoma resulted in improvement of at least one grade in 35 patients, while four patients had complete motor paralysis even after evacuation surgery.

Conclusions

We report the clinical details of 45 patients with postoperative hematoma after spine surgery. This information could assist surgeons to make a prompt diagnosis and perform early evacuation surgery for postoperative hematoma following spine surgery.

Evaluation of Postoperative Spinal Epidural Hematoma After Biportal Endoscopic Spine Surgery for Single-Level Lumbar Spinal Stenosis: Clinical and Magnetic Resonance Imaging Study

BACKGROUND

Symptomatic postoperative spinal epidural hematoma is a serious complication that may occur after lumbar spine surgery. We analyzed epidural hematoma using postoperative magnetic resonance imaging (MRI) after biportal endoscopic spinal surgery and its impact on clinical outcome.

METHODS

The subjects of this study were 158 patients who underwent single-level decompression using the biportal endoscopic spinal surgery technique from 2015 to 2017. MRI was performed in all patients before and after surgery, and postoperative MRI was used to identify epidural hematoma. The preoperative and postoperative visual analog scale (VAS) score for leg and back pain, Oswestry Disability Index (ODI), and modified Macnab criteria were recorded for evaluation of clinical outcome. The group with postoperative spinal epidural hematoma (group A) and without hematoma (group B) were comparatively analyzed, both radiologically and clinically.

RESULTS

The mean age of the patients was 67.9 ± 11.1 years (range, 49-89). The total number with grade 0 (no hematoma) was 119 levels patients (75.3%) on the T2 axial image of postoperative MRI. The total number of patients with hematoma was 39 (24.7%) according to T2-weighted axial postoperative MRI. Two patients underwent revision surgery because of hematoma-related symptoms. The improvement of clinical outcome measures including VAS leg, VAS back, and ODI was significantly different between group A and B (P < 0.05).

CONCLUSIONS

The incidence of postoperative spinal epidural hematoma after biportal endoscopic spinal surgery according to postoperative MRI was higher than expected, regardless of the patients' postoperative symptoms. Postoperative hematoma has a decisive influence on postoperative results, and revision surgery might be necessary if canal encroachment is >50% with concomitant symptoms.

Impact of lumbar hypolordosis on the incidence of symptomatic postoperative spinal epidural hematoma after decompression surgery for lumbar spinal canal stenosis

PURPOSE

Potential associations between radiographic parameters and the incidence of symptomatic postoperative spinal epidural hematoma (PSEH) have not been identified. This study aimed to identify risk factors including radiographic parameters for symptomatic PSEH after posterior decompression surgery for lumbar spinal canal stenosis (LSS).

METHODS

We retrospectively reviewed 1007 consecutive patients who underwent lumbar decompression surgery for lumbar spinal canal stenosis (LSS) at our institution. We identified 35 cases of symptomatic PSEH, defined by clinical symptoms and MRI findings, and selected 3 or 4 age- and sex-matched control subjects for each PSEH subject (124 controls). We compared radiographic parameters and previously reported risk factors between PSEH and control subjects.

RESULTS

Compared to the control group, PSEH patients had significantly higher preoperative systolic (p = .020) and diastolic (p = .048) blood pressure, and more levels of decompression (p = .001). PSEH and control subjects had significant differences in lumbar lordosis (PSEH 24.8° ± 14.6°, control 34.8° ± 14.5°), pelvic tilt (25.1° ± 11.7° vs. 20.8° ± 8.4°), sacral slope (23.4° ± 9.4° vs. 27.6° ± 8.3°), and pelvic incidence minus lumbar lordosis (23.7° ± 15.0° vs. 13.7° ± 14.6°). Multivariate analysis revealed two significant risk factors for PSEH: decompression of two or more levels and lumbar lordosis < 25°.

CONCLUSIONS

Multilevel decompression and hypolordosis are significant risk factors for symptomatic PSEH after decompression surgery for LSS. LSS patients with lumbar hypolordosis or multilevel stenosis should be carefully observed for PSEH after decompression surgery. These slides can be retrieved under Electronic Supplementary Material.