Impact of Obesity on Postoperative Complications after Lateral Skull Base Surgery: A Systematic Review

INTRODUCTION

The relationship between obesity and complications after lateral skull base tumor resection is not clear. There is conflicting evidence regarding the incidence of postoperative complications in this patient population. The purpose of this study is to examine the relationship between obesity and outcomes following lateral skull base tumor resection.

DATA SOURCES

Data were extracted from PubMed, Embase, CINAHL, and Cochrane CENTRAL.

METHODS

Included studies assessed the relationship between obesity and outcomes following lateral skull base tumor removal. Studies with ≤5 patients, pediatric patients, duplicate patient populations, or insufficient data were excluded. Two independent investigators reviewed each study for inclusion. A third reviewer served as a tie-breaker for any conflicts. Extracted data includes patient demographics, tumor pathology, surgical approach, and postoperative outcomes including incidence of cerebrospinal fluid (CSF) leak and other postoperative complications, length of stay (LOS), and readmission and reoperation rates. Descriptive statistics were used to compare postoperative outcomes for obese and nonobese controls.

RESULTS

14 studies met final inclusion criteria. Nine studies evaluated the relationship between obesity and CSF leaks. Four studies found a significant increase in postoperative CSF leak in obese patients compared to nonobese controls. The remaining studies trended toward an increased incidence of CSF leak in the obese population but did not reach statistical significance. One out of seven studies found that obesity increased postoperative LOS, and one out of five studies found that obesity increased reoperation rates following tumor resection.

CONCLUSIONS

Based on the results, obesity does not appear to increase LOS, readmission, or reoperation rates after lateral skull base tumor resection. The relationship between obesity and postoperative CSF leak, however, warrants further analysis.

Elevated Body Mass Index Associated with Cerebrospinal Fluid Leak after Lateral Skull Base Surgery: A Systematic Review and Meta-analysis

OBJECTIVE

To determine if body mass index (BMI) increases the risk of cerebrospinal fluid (CSF) leak after lateral skull base surgery.

DATA SOURCES

CINAHL, PubMed, and Scopus were searched from January 2010 to September 2022 for articles published in English.

STUDY SELECTION

Articles that reported BMI or obesity with and without CSF leaks after lateral skull base surgery were included.

DATA EXTRACTION

Two reviewers (F.G.D. and B.K.W.) independently performed study screening, data extraction, and risk of bias assessment.

DATA SYNTHESIS

A total of 11 studies and 9,132 patients met inclusion criteria. Meta-analysis of mean difference (MD), odds ratio (OR), proportions, and risk ratio (RR) were calculated using RevMan 5.4 and MedCalc 20.110. BMI for patients with CSF leak after lateral skull base surgery (29.39 kg/m2, 95% confidence interval [CI] = 27.75 to 31.04) was significantly greater than BMI for patients without CSF leak after lateral skull base surgery (27.09 kg/m2, 95% CI = 26.16 to 28.01) with an MD of 2.21 kg/m2 (95% CI = 1.09 to 3.34, p = 0.0001). The proportion of patients with BMI ≥ 30 kg/m2 that had a CSF leak was 12.7%, and the proportion of patients with BMI < 30 kg/m2 (control) that had a CSF leak was 7.9%. The OR for CSF leak after lateral skull base surgery in patients with BMI ≥ 30 kg/m2 was 1.94 (95% CI = 1.40 to 2.68, p < 0.0001), and the RR was 1.82 (95% CI = 1.36 to 2.43, p < 0.0001).

CONCLUSION

Elevated BMI increases the risk of CSF leak after lateral skull base surgery.

LEVEL OF EVIDENCE

IIa.

Risk factors for 30-day postoperative surgical site hematoma requiring evacuation after resection of brain metastases

OBJECTIVE

To identify the risk factors for a 30-day postoperative surgical site hematoma requiring evacuation (POH) after surgical resection of brain metastases.

METHODS

Patients who underwent surgical resection of brain metastases between 2011 and 2019 at our institution were included. Risk factors for a 30-day POH were identified using a multivariate logistic regression model.

RESULTS

A total of 158 patients were included in the analysis. The mean (SD) age of the study population was 59.3 (12.0) years, and 82 (53.2%) patients were female. The incidence of a 30-day POH was 8.2% (13 patients). There was no statistically significant association between the occurrence of a 30-day POH and overall mortality (p = 0.100). On multivariate analysis, there was a statistically significant association between a 30-day POH and younger age (OR=0.91; 95% CI=0.83, 0.99; p = 0.035), higher BMI (OR=1.61; 95% CI=1.16, 2.46; p = 0.010), and blood type AB (OR=21.7; 95% CI=1.66, 522; p = 0.031). On receiver operating characteristic analysis, a threshold BMI of 25.1 kg/m² and threshold age of 57 gave the optimum balance of sensitivity and specificity in predicting the occurrence of a 30-day POH.

CONCLUSIONS

Patients below 57 years old, who have a BMI of above 25, and/or have blood type AB were at higher risk of developing a 30-day POH after surgical resection of brain metastases. Additional care in intraoperative hemostasis and postoperative monitoring may be indicated among patients who have these risk factors.

Risk Factors for Complications Following Lateral Skull Base Surgery and the Utility of ICU Monitoring

OBJECTIVE

To examine the role of intensive care unit (ICU) management following lateral skull base surgery for vestibular schwannoma and identify risk factors for complications warranting admission to the ICU.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

Two hundred consecutive patients undergoing lateral skull base surgery for vestibular schwannomas.

INTERVENTION

Lateral skull base approach for resection of vestibular schwannoma and postoperative monitoring.

MAIN OUTCOME MEASURES

Patients were grouped if they sustained an ICU complication, a non-ICU complication, or no complication. Analysis was performed to determine patient or treatment factors that may be associated with ICU complications. Multivariate and three-way analysis of variance compared groups, and multivariate logistic regression determined adjusted odds ratios (aOR) for analyzed factors.

RESULTS

Seventeen of 200 patients sustained ICU complications (8.5%), most commonly hypertensive urgency (n = 15). Forty-six (23%) sustained non-ICU complications, and 137 (68.5%) had no complications. When controlling for age, sex, obesity, and other comorbidities, only hypertension (aOR 5.43, 95% confidence interval (CI) 1.35-21.73, p = 0.017) and tumor volume (aOR 3.29, 95% CI 1.09-9.96, p = 0.035) were independently associated with increased risk of ICU complications.

CONCLUSIONS

The necessity of intensive care following lateral skull base surgery is rare, with the primary ICU complication being hypertensive urgency. Preoperative hypertension and large tumor volume (>4500 mm3) were independently associated with increased risk for ICU complications. These findings may allow for risk stratification of patients appropriate for admission to stepdown units following resection of vestibular schwannomas. Further prospective, multi-center, randomized studies are necessary to validate these findings before systematic changes to current postoperative care practices.

Investigating Predictors of Increased Length of Stay After Resection of Vestibular Schwannoma Using Machine Learning

OBJECTIVE

To evaluate the predictors of prolonged length of stay (LOS) after vestibular schwannoma resection.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Patients who underwent vestibular schwannoma resection between 2008 and 2019.

INTERVENTIONS

Variables of interest included age, body mass index, comorbidities, symptoms, previous intervention, microsurgical approach, extent of resection, operative time, preoperative tumor volume, and postoperative complications. Predictive modeling was done through multivariable linear regression and random forest models with 80% of patients used for model training and the remaining 20% used for performance testing.

MAIN OUTCOME MEASURES

LOS was evaluated as the number of days from surgery to discharge.

RESULTS

Four hundred one cases from 2008 to 2019 were included with a mean LOS of 3.0 (IQR = 3.0-4.0). Postoperatively, 14 (3.5%) of patients had LOS greater than two standard deviations from the mean (11 days). In a multivariate linear regression model (adjusted R2 = 0.22; p < 0.001), preoperative tumor volume (p < 0.001), coronary artery disease (p = 0.002), hypertension (p = 0.029), and any major complication (p < 0.001) were associated with increased LOS (by 0.12, 3.79, 0.87, and 3.20 days respectively). A machine learning analysis using a random forest identified several potential nonlinear relationships between LOS and preoperative tumor dimensions (length, volume) and operative time that were not captured on regression. The random forest model had lower prediction error compared to the regression model (RMSE 5.67 vs. 44.59).

CONCLUSIONS

Tumor volume, coronary artery disease, hypertension, and major complications impact LOS. Machine learning methods may identify nonlinear relationships worthy of targeted clinical investigation and allow for more accurate patient counseling.

Implications of Obesity on Endoscopic Sinus Surgery Postoperative Complications: An Analysis of the NSQIP Database

Objective

To evaluate the influence of body mass index on postoperative adverse events in adult patients undergoing endoscopic sinus surgery.

Study Design

Retrospective cohort study.

Setting

Database of the American College of Surgeons NSQIP (National Surgical Quality Improvement Program) from 2006 to 2018.

Methods

The NSQIP database was queried for adult patients undergoing endoscopic sinus surgery. The total sample (N = 1546) was stratified by nonobese (18.5 kg/m2≤ body mass index <30 kg/m2) and obese (≥30 kg/m2). Demographics, comorbidities, intraoperative variables, and postoperative adverse events were compared via chi-square analysis and multivariable logistic regression.

Results

Obese patients accounted for 49.7% (n = 768) of the cohort. Obese patients had a higher American Society of Anesthesiologists classification (class III, 45.1% vs 29.5%; P < .001), rate of diabetes (18.2% vs 7.2%, P < .001), and rate of hypertension requiring medication (43.1% vs 23.0%, P < .001). Nonobese patients were more likely to be >58 years of age (23.4% vs 29.0%, P = .02) and have disseminated cancer (<1% vs 3.2%, P < .001). The obese cohort had a lower frequency of surgical complications (3.0% vs 5.4%, P = .027), driven by frequency of perioperative bleeding (1.8% vs 3.7%, P = .022). There was no statistical difference in medical complications ( P = .775), unplanned readmissions ( P = .286), unplanned reoperations ( P = .053), or 30-day mortality ( P > .999). After multivariable adjustment, obese subjects had decreased odds of any surgical complication (adjusted odds ratio [aOR], 0.567; 95% CI, 0.329-0.979), perioperative bleeding (aOR, 0.474; 95% CI, 0.239-0.942), and any adverse postoperative event (aOR, 0.740; 95% CI, 0.566-0.968).

Conclusion

Obesity does not increase the risk of 30-day adverse outcomes following endoscopic sinus surgery and may even be protective against perioperative bleeding.

The association of age, body mass index, and frailty with vestibular schwannoma surgical morbidity

OBJECTIVE

To evaluate whether increased body mass index (BMI), age, or frailty influence vestibular schwannoma (VS) short-term surgical morbidity.

METHODS

The 2005-2017 National Surgical Quality Improvement Program database was queried for patients with VS undergoing surgical resection. Age was stratified according to age <50, 50-64, and ≥65, while BMI was stratified based on a threshold of 30. Frailty score (0-5) was indicated based on functional status, diabetes, chronic obstructive pulmonary disease, congestive heart failure, and hypertension.

RESULTS

A total of 1405 patients were included consisting of 56.7 % females with a mean age of 50.7 ± 13.8 years and mean BMI of 29.4 ± 6.6. Patients <50 (n = 604), 50-64 (n = 578), and ≥65 (n = 223), had different duration of surgery (428 ± 173 vs. 392 ± 149 vs. 387 ± 154 min; p < 0.001) and 30-day mortality rates (0.7 % vs. 0% vs. 1.8 %; p = 0.01). However, post-operative length of stay (LOS) (p = 0.16), readmission (p = 0.08), reoperation (p = 0.54), and complication rates were similar. Post-operative myocardial infarction (p = 0.03) and wound infection (p = 0.02) were more commonly observed in the obese cohort (BMI≥30) but readmission (p = 0.18), reoperation (p = 0.44), and complication rates were similar to those with BMI<30. Severely obese patients (BMI≥35) also had higher rates of deep vein thrombosis (p = 0.004). Frailty score 0 (n=921), 1 (n=375), and 2-4 (n=109) was associated with LOS (4.7±3.5 vs. 5.3 ± 4.1 vs. 6.7 ± 6.6 days, p < 0.001) and prolonged intubation rates (1.0 % vs. 2.4 % vs. 3.7 %; p = 0.03).

CONCLUSIONS

Increased age, BMI, and frailty among VS patients were associated with different post-operative complication rates, operation time, or LOS. Knowledge of these can optimize care for at-risk patients.