Underweight patients are at just as much risk as super morbidly obese patients when undergoing anterior cervical spine surgery

Influence of Body Mass Index on Surgical and Patient Outcomes for Cervical Spine Surgery

STUDY DESIGN

Secondary analysis of prospectively collected registry.

OBJECTIVE

We aim to investigate the effects of body mass index (BMI) on postsurgical cervical spine surgery outcomes and identify a potential substratification of obesity with worse outcomes.

SUMMARY OF BACKGROUND DATA

The impact of BMI on cervical spine surgery is unknown, with controversial outcomes for patients high and low BMI.

METHODS

The cervical spine Quality Outcomes Database was queried for a total of 10,381 patients who underwent single-stage cervical spine surgery. Patients were substratified into 6 groups based on BMI. Surgical outcomes, complications, hospitalization outcomes, and patient-reported outcomes for each cohort, including modified Japanese Orthopedic Association Score, Numeric Rating Scale arm pain, Numeric Rating Scale neck pain, Neck Disability Index, and EuroQol Health Survey, were assessed. Univariate analysis was performed for 3- and 12-month follow-up after surgical intervention.

RESULTS

Obese patients (class I, II, and III) requiring spine surgery were statistically younger than nonobese patients and had higher rates of diabetes compared with normal BMI patients. The surgical length was found to be longer for overweight and all classes of obese patients ( P < 0.01). Class III obese patients had higher odds of postoperative complications. Patients with class II and III obesity had lower odds of achieving optimal modified Japanese Orthopedic Association Score at 3 months [OR = 0.8 (0.67-0.94), P < 0.01, OR = 0.68 (0.56-0.82), P < 0.001, respectively] and 12 months [OR = 0.82 (0.68-0.98), P = 0.03, OR = 0.79 (0.64-0.98), P = 0.03, respectively].

CONCLUSIONS

This study investigates the relationship between substratified BMI and postoperative outcomes of cervical spine surgery. Class II and III obese patients have substantially greater risk factors and poor outcomes postoperatively. In addition, low BMI also presents unique challenges for patients. Further research is needed for comprehensive analysis on outcomes of cervical spine surgery after correcting BMI.

Low Body Mass Index Patients Undergoing an Anterior Lumbar Fusion May Have an Increased Risk of Perioperative Complications

BACKGROUND

Previous research has shown that underweight patients may be at a greater risk of experiencing postsurgical complications. The purpose of this study was to investigate the association between body mass index (BMI) and postoperative complications following single-level anterior lumbar fusion (ALF).

METHODS

All single-level elective ALF procedures performed between 2010 and 2020 were identified in the PearlDiver Mariner Database. Patients were separated into 6 groups based on the World Health Organization BMI classifications. Differences in postsurgical complications (ie, deep vein thrombosis, pulmonary embolism, surgical site infection, hardware malfunction, wound dehiscence, and blood transfusion) among BMI categories were assessed using a χ2 contingency test.

RESULTS

Results indicated that underweight patients (BMI <20) were at a significantly greater risk of developing deep vein thromboses, experiencing hardware malfunction, and requiring blood transfusion compared with any other BMI classification (P < 0.001). Results also demonstrated that underweight individuals had similar risks of developing surgical site infection and wound dehiscence compared with patients classified as having obesity class III.

CONCLUSION

Underweight patients may be at a greater risk than currently believed of experiencing postoperative complications following single-level ALF procedures.

CLINICAL RELEVANCE

Patients with a BMI of 20 or less should be carefully evaluated prior to surgical intervention to ensure they are optimized for surgery.

LEVEL OF EVIDENCE: 3

Use of the Geriatric Nutritional Risk Index to Assess Risk for Postoperative Complications Following Posterior Cervical Decompression/Fusion

BACKGROUND

Posterior cervical decompression with or without fusion (PCD/F) is used to manage degenerative spinal conditions. Malnutrition has been implicated for poor outcomes in spine surgery. The aim of this study was to assess the ability of the Geriatric Nutritional Risk Index (GNRI) as a risk calculator for postoperative complications in patients undergoing PCD/F.

METHODS

The 2006 to 2018 American College of Surgeons National Surgery Quality Improvement Program Database was queried for patients undergoing PCD/F. Nutritional status was categorized as normal (GNRI greater than 98), moderately malnourished (GNRI 92-98), or severely malnourished (GNRI less than or equal to 92). Complications within 30 days of surgery were compared among the groups. Preoperative data that were statistically significant (P < 0.05) upon univariate χ2 analysis were included in the univariate then multivariate binary regression model to calculate adjusted ORs. All ORs were assessed at the 95% CI.

RESULTS

Of the 7597 PCD/F patients identified, 15.6% were severely malnourished and 19.1% were moderately malnourished. Severe and moderate malnourishment were independent risk factors for mortality (OR = 3.790, 95% CI 2.492-5.763, P < 0.001; OR = 2.150, 95% CI 1.351-3.421, P = 0.011). Severe malnourishment was an independent risk factor for sepsis/septic shock (OR = 3.448, 95% CI 2.402-4.948, P < 0.001).

CONCLUSIONS

In elderly patients undergoing PCD/F, severe malnutrition, as defined by the GNRI, was an independent risk factor for mortality and sepsis/septic shock.

CLINICAL RELEVANCE

The GNRI may be more useful than other indices for risk stratification in elderly patients because it accounts for confounding variables such as hydration status and paradoxical malnourishment in obese patients.

LEVEL OF EVIDENCE: 3

Association of body mass index with perioperative blood transfusion and short-term clinical outcomes in patients undergoing isolated coronary artery bypass grafting

BACKGROUND

Few studies have considered outcomes among low body mass index (BMI) cohorts undergoing coronary artery bypass grafting (CABG). This study aims to investigate the effects of low body weight on blood transfusion and perioperative outcomes in patients undergoing isolated CABG.

METHODS

This retrospective study enrolled consecutive cases from a single-center between January 2008 and December 2018. Low body weight/underweight was defined as a BMI < 18.5 kg/m², while normal BMI was defined as 18.5 ≤ BMI < 24.0 kg/m². The primary endpoint was the perioperative red blood cell (RBC) transfusion rate. Secondary endpoints include platelet and plasma transfusion rates, transfusion volume for all blood components, hospital length of stay, and the occurrence of adverse events including prolonged mechanical ventilation, re-intubation, re-operation, acute kidney injury, and 30-day all-cause mortality.

RESULTS

A total of 7,620 patients were included in this study. After 1:1 propensity score matching, 130 pairs were formed, with 61 pairs in the on-pump group and 69 pairs in the off-pump group. Baseline characteristics were comparable between the matched groups. Low body weight independently increased the risk of RBC transfusion (on-pump: OR = 3.837, 95% CI = 1.213-12.144, p = 0.022; off-pump: OR = 3.630, 95% CI = 1.875-5.313, p < 0.001). Moreover, within the on-pump group of the original cohort, BMI of < 18.5 kg/m² was independently correlated with increased risk of re-intubation (OR = 5.365, 95% CI = 1.159 to 24.833, p = 0.032), re-operation (OR = 4.650, 95% CI = 1.019 to 21.210, p = 0.047), and 30-day all-cause mortality (OR = 10.325, 95% CI = 2.011 to 53.020, p = 0.005).

CONCLUSION

BMI < 18.5 kg/m² was identified as an independent risk factor for increased perioperative RBC transfusion rate in patient underwent isolated CABG with or without CPB. Only on-pump underweight patients in the original cohort exhibited an increased risk for re-intubation, re-operation, and 30-day all-cause mortality. Physicians and healthcare systems should consider these findings to improve management for this population.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

Modified frailty index independently predicts morbidity in patients undergoing 3-column osteotomy

PURPOSE

Adult Spinal Deformity (ASD) includes a spectrum of spinal conditions that can be associated with significant pain and loss of function. While 3-column osteotomies have been the procedures of choice for ASD patients, there is also a substantial risk for complications. The prognostic value of the modified 5-item frailty index (mFI-5) for these procedures has not yet been studied. The goal of this study is to evaluate the association of mFI-5 with 30-day morbidity, readmission, and reoperation following a 3-column osteotomy.

METHODS

The National Surgical Quality Improvement Program (NSQIP) database was queried to identify patients undergoing 3-Column Osteotomy procedures from 2011-2019. Multivariate modeling was utilized to assess mFI-5 and other demographic, comorbidity, laboratory, and perioperative variables as independent predictors of morbidity, readmission, and reoperation.

RESULTS

N = 971. Multivariate analysis revealed that mFI-5 = 1 (OR = 1.62, p = 0.015) and mFI-5 ≥ 2 (OR = 2.17, p = 0.004) were significant independent predictors of morbidity. mFI-5 ≥ 2 was a significant independent predictor of readmission (OR = 2.16, p = 0.022) while mFI-5 = 1 was not a significant predictor of readmission (p = 0.053). Frailty did not predict reoperation.

CONCLUSION

Frailty as defined by mFI-5 strongly and independently predicted increased odds of postoperative morbidity for patients undergoing 3-column osteotomy as surgical intervention for ASD. Only mFI-5 ≥ 2 was a significant independent predictor of readmission, while frailty did not predict reoperation. Other variables independently predicted increased and decreased odds of postoperative morbidity, readmission, and reoperation.

LEVEL OF EVIDENCE

III.

Body Mass Index and Risk of Complications After Posterior Lumbar Spine Fusion: A Matched Cohort Analysis Investigating Underweight and Obese Patients

OBJECTIVE

Previous studies have demonstrated that obesity is associated with increased complications after lumbar fusion. However, there are little published data on the effect of being underweight on lumbar fusion outcomes. The purpose of this study was to elucidate the effect of being underweight versus obese on outcomes after lumbar spinal fusion.

METHODS

Lumbar spinal fusion patients were identified through the PearlDiver Mariner database between 2010 and 2020. Study groups were created using International Classification of Diseases codes to identify preoperative body mass index (BMI) category as morbid obesity (BMI > 40), obesity (BMI 30 to 40), normal BMI (BMI 20 to 30), and underweight (BMI < 20) cohorts. Complications that occurred within 1 year postoperatively in this study and matched control groups were then isolated. Statistical analyses were conducted using the Pearson chi square method.

RESULTS

A total of 62,616 patients were identified in this analysis. This included 1,258 underweight patients (4.0%), 17,996 obese patients (57.5%), and 12,054 morbidly obese patients (38.5%). The number of patients to experience any postoperative complication was 766 (60.9%), 9,440 (52.4%), and 6,982 (57.9%) for the underweight, obese, and morbidly obese cohorts, respectively. Underweight patients showed an increased likelihood of complications related to instrumentation (odds ratio [OR] 1.85, P = 0.0237), revision fusion (OR 1.34, P = 0.04061), pulmonary complications (OR 1.43, P < 0.001), and sepsis (OR 1.91, P < 0.001). Obese patients with BMI 30 to 40 showed increased odds of the following complications: hemorrhages and hematomas (OR 1.20, P = 0.02634), surgical site complications (OR 1.27, P < 0.001), thromboembolism (OR 1.78, P < 0.001), and urinary complications (OR 1.08, P < 0.001). Morbidly obese patients with BMI > 40 showed increased odds of all complications analyzed in this study.

CONCLUSION

This investigation indicates that both underweight and obese patients are at elevated risk of complications after lumbar fusion. Similar to obese patients, underweight patients may benefit from preoperative optimization by nutrition counseling to avoid potential complications.

LEVEL OF EVIDENCE

III.

The Effect of the Coronavirus Disease 2019 (COVID-19) Pandemic on Elective Cervical Spine Surgery Utilization and Complications in the United States: A Nationwide Temporal Trends Analysis

OBJECTIVES

As a result of the coronavirus disease 2019 (COVID-19) pandemic, elective surgeries nationwide were suspended. The objective was to compare temporal trends in patient demographics, case volumes, and postoperative complications of patients undergoing elective cervical spine surgery from pre-COVID-19 (2019-2020 Q1) to post-COVID-19 (2020 Q2-Q4).

METHODS

The 2019 to 2020 American College of Surgeon's National Surgery Quality Improvement Program database was queried for common elective cervical spine surgeries. Patients pre-COVID-19 (2019-2020 Q1) were compared with those undergoing surgery during post-COVID-19 (2020 Q2-Q4) protocols. Procedural use, patient demographics, and complications were compared. Linear regression was used to evaluate case volume changes over time. P values less than 0.05 were significant.

RESULTS

In total, 31,013 patients underwent elective cervical spine surgery in 2019 (N = 16,316) and 2020 (N = 14,697); an overall 10% decline. Compared with the calendar year 2019 through 2020 Q1 mean, elective surgery volume decreased by 21.6% in 2020 Q2 and never returned to prepandemic baseline. The percentage decline in case volume from 2019 to 2020 Q1 to 2020 Q2 was greatest for anterior cervical discectomy and fusion (23.3%), followed by cervical decompression (23.4%), posterior cervical fusion (15.0%), and cervical disc arthroplasty and vertebral corpectomy (13.7%). Patients undergoing surgery in 2020 Q2-Q4 had overall greater comorbidity burden (American Society of Anesthesiologists grade 3 and 4) (P < 0.001). From 2019-2020 Q1 versus 2020 Q2-Q4, there was a significant increase in total complication (5.5% vs. 6.8%, P < 0.001), reoperation (1.9% vs. 2.2%, P = 0.048), and mortality (0.25% vs. 0.37%, P = 0.049) rates.

CONCLUSIONS

Elective surgery declined drastically during the second quarter of 2020. Patients undergoing surgery during the pandemic had an overall greater comorbidity burden, resulting in increased total complication and mortality rates over the study period.

Effect of low body mass index on clinical recovery after fusion surgery for osteoporotic vertebral fracture: A retrospective, multicenter study of 237 cases

A retrospective multicenter study. Body mass index (BMI) is recognized as an important determinant of osteoporosis and spinal postoperative outcomes; however, the specific impact of BMI on surgery for osteoporotic vertebral fractures (OVFs) remains inconclusive. This retrospective multicenter study investigated the impact of BMI on clinical outcomes following fusion surgery for OVFs. 237 OVF patients (mean age, 74.3 years; 48 men and 189 women) with neurological symptoms who underwent spinal fusion were included in this study. Patients were grouped by World Health Organization BMI categories: low BMI (<18.5 kg/m2), normal BMI (≥18.5 and <25 kg/m2), and high BMI (≥25 kg/m2). Patients' backgrounds, surgical method, radiological findings, pain measurements, activities of daily living (ADL), and postoperative complications were compared after a mean follow-up period of 4 years. As results, the proportion of patients able to walk independently was significantly smaller in the low BMI group (75.0%) compared with the normal BMI group (89.9%; P = .01) and the high BMI group (94.3%; P = .04). Improvement in the visual analogue scale for leg pain was significantly less in the low BMI group than the high BMI group (26.7 vs 42.8 mm; P = .046). Radiological evaluation, the Frankel classification, and postoperative complications were not significantly different among all 3 groups. Improvement of pain intensity and ADL in the high BMI group was equivalent or non-significantly better for some outcome measures compared with the normal BMI group. Leg pain and independent walking ability after fusion surgery for patients with OVFs improved less in the low versus the high BMI group. Surgeons may want to carefully evaluate at risk low BMI patients before fusion surgery for OVF because poor clinical results may occur.

Underweight patients are the highest risk body mass index group for perioperative adverse events following stand-alone anterior lumbar interbody fusion

BACKGROUND CONTEXT

Prior studies investigating the association between Body Mass Index (BMI) and patient outcomes following spine surgery have had inconsistent conclusions, likely owing to insufficient power, confounding variables, and varying definitions and cutoffs for BMI categories (eg, underweight, overweight, obese, etc.). Further, few studies have considered outcomes among low BMI cohorts.

PURPOSE

The current study analyzes how anterior lumbar interbody fusion (ALIF) perioperative outcomes vary along the BMI spectrum, using World Health Organization (WHO) categories of BMI.

STUDY DESIGN/SETTING

A retrospective cohort study.

PATIENT SAMPLE

Patients undergoing stand-alone one or two-level anterior lumbar interbody fusion (ALIF) found in the 2005-2018 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) databases.

OUTCOME MEASURES

Thirty-day adverse events, hospital readmissions, post-operative infections, and mortality.

METHODS

Stand-alone one or two-level ALIF surgical cases were identified and extracted from the 2005-2018 National Surgical Quality Improvement Program (NSQIP) database. Posterior cases and those primary diagnoses of trauma, tumor, infection, or emergency presentation were excluded. Patients were then binned into WHO guidelines of BMI. The incidence of adverse outcomes within 30-day post-operation was defined. Odds ratios of adverse outcomes, normalized to the average risk of normal-weight subjects (BMI 18.5-24.9 kg/m³), were calculated. Multivariate analysis was then performed controlling for patient factors.

RESULTS

In total, 13,710 ALIF patients were included in the study. Incidence of adverse events was elevated in both the underweight (BMI<18.5 kg/m³) and super morbidly obese (>50 kg/m³), however, multivariate risks for adverse events and postoperative infection were elevated for underweight patients beyond those found in any other BMI category. No effect was noted in these identical variables between normal, overweight, obese class 1, or even obese class 2 patients. Multivariate analysis also found overweight patients to show a slightly protective trend against mortality while the super morbidly obese had elevated odds.

CONCLUSIONS

Underweight patients are at greater odds of experiencing postoperative adverse events than normal, overweight, obese class 1, or even obese class 2 patients. The present study identifies underweight patients as an at-risk population that should be given additional consideration by health systems and physicians, as is already done for those on the other side of the BMI spectrum.

Survival bias may explain the appearance of the obesity paradox in hip fracture patients

Patients with low-energy hip fractures do not follow the obesity paradox as previously reported. In datasets where injury mechanism is not available, the use of age >50 years (as opposed to commonly used >65 years) as a surrogate for a low-energy hip fracture patients may be a more robust inclusion criterion.  PURPOSE: In elderly patients with a hip fracture, limited data suggests that obese patients counterintuitively have improved survival compared to normal-weight patients. This "obesity paradox" may be the byproduct of selection bias. We hypothesized that the obesity paradox would not apply to elderly hip fracture patients.

METHODS

The National Surgical Quality Improvement Project dataset identified 71,685 hip fracture patients ≥50 years-of-age with complete body mass index (BMI) data that underwent surgery. Patients were stratified into under and over 75-year-old cohorts (n=18,956 and 52,729, respectively). Within each age group, patients were stratified by BMI class and compared with respect to preoperative characteristics and 30-day mortality. Significant univariate characteristics (p<0.1) were included in multivariate analysis to determine the independent effect of obesity class on 30-day mortality (p<0.05).

RESULTS

Multivariate analysis of <75-year-old patients with class-III obesity were more likely to die within 30-days than similarly aged normal-weight patients (OR 1.91, CI 1.06-3.42, p=0.030). Multivariate analysis of ≥75-year-old overweight (OR 0.69, CI 0.62-0.77, p<0.001), class-I obese (OR 0.62, CI 0.51-0.74, p<0.001), or class-II obese (OR=0.69, CI 0.50-0.95, p=0.022) patients were less likely to die within 30-days when compared to similarly aged normal-weight patients.

CONCLUSIONS

Our data suggest that obesity is a risk factor for mortality in low-energy hip fracture patients, but the appearance of the "obesity paradox" in elderly hip fracture patients results from statistical bias that is only evident upon subgroup analysis.

BMI Specific Complications Following Implant-Based Breast Reconstruction after Mastectomy

Background: Breast reconstruction has a positive impact on body image and quality of life for women after experiencing the physically and psychologically demanding process of mastectomy. Previous studies have presented body mass index (BMI) as a predictor for postoperative complications after breast reconstruction, however, study results vary. This retrospective study aimed to investigate the impact of patients’ BMI on postoperative complications following implant-based breast reconstruction. Methods: All implant-based breast reconstructions performed at the Department of Plastic, Reconstructive and Aesthetic Surgery at the Medical University of Vienna from January 2001 to March 2018 were evaluated. A total of 196 reconstructed breasts among 134 patients met eligibility criteria. Demographic data, surgical techniques, as well as major and minor complications within a one-year follow-up period were analyzed. Results: Patients’ BMI did not show a significant impact on complication rates. The overall incidence of postoperative complications was 30.5% (40/131) of which 17.6% required reoperation. Impaired wound healing (18.3%), seroma (6.1%), hematoma (4.6%), capsular contraction (4.6%) and infection (3.8%) were the most common complications. Conclusion: In our study cohort, BMI was not associated with a significantly higher risk of complications. However, postoperative complications significantly increased with a longer operative time and resulted in an extended length of hospital stay.

30-Day Outcomes for Total Ankle Arthroplasty in Patients With Anemia

BACKGROUND

While anemia has been associated with poor surgical outcomes in total knee arthroplasty and total hip arthroplasty, the effects of anemia on total ankle arthroplasty remain unknown. This study examines how preoperative anemia affects postoperative outcomes in total ankle arthroplasty.

METHODS

A retrospective analysis was performed using the American College of Surgeons National Surgery Quality Improvement Project database from 2011 to 2018 for total ankle arthroplasty procedures. Hematocrit (HCT) levels were used to determine preoperative anemia.

RESULTS

Of the 1028 patients included in this study, 114 patients were found to be anemic. Univariate analysis demonstrated anemia was significantly associated with an increased average hospital length of stay (2.2 vs 1.8 days, P < .008), increased rate of 30-day readmission (3.5% vs 1.1%, P = .036), increased 30-day reoperation (2.6% vs 0.4%, P = .007), extended length of stay (64% vs 49.9%, P = .004), wound complication (1.75% vs 0.11%, P = .002), and surgical site infection (2.6% vs 0.6%, P = .017). Multivariate logistic regression analysis found anemia to be significantly associated with extended hospital length of stay (odds ratio [OR], 1.62; 95% CI, 1.07-2.45; P = .023) and increased reoperation rates (OR, 5.47; 95% CI, 1.15-26.00; P = .033). Anemia was not found to be a predictor of increased readmission rates (OR, 3.13; 95% CI, 0.93-10.56; P = .066) or postoperative complications (OR, 1.27; 95% CI, 0.35-4.56; P = .71).

CONCLUSION

This study found increasing severity of anemia to be associated with extended hospital length of stay and increased reoperation rates. Providers and patients should be aware of the increased risks of total ankle arthroplasty with preoperative anemia.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Association of Body Mass Index with Outcomes after Carotid Endarterectomy

BACKGROUND

Patients who are obese or underweight are traditionally at higher risk for perioperative morbidity and mortality. The effect of body mass index (BMI) on outcomes after carotid endarterectomy (CEA) is unclear. Our goal was to analyze the association of BMI with perioperative and long-term outcomes after elective CEA.

METHODS

The Vascular Quality Initiative (VQI) database was queried from 2003-2018 for patients undergoing elective CEAs. Patients were categorized into 5 BMI cohorts - underweight (UW, BMI < 18.5 kg/m²), normal weight (NW, BMI 18.5-24.9 kg/m²), overweight (OW, BMI 25-29.9 kg/m²), obese (OB, BMI 30-39.9 kg/m²), and morbidly obese (MO, BMI ≥ 40 kg/m²). Perioperative and long-term outcomes were assessed with univariable and multivariable analyses.

RESULTS

There were 89,079 patients included: 2% UW, 26% NW, 38.4% OW, 29.9% OB, and 3.6% MO. Overall, the mean age was 70.6 years, 60% were male, and 91.8% were of white race. There were significant differences among the BMI cohorts in regards to age, sex, smoking status, and comorbidities (all P < 0.05). For perioperative outcomes, the BMI cohorts differed significantly in reoperation for bleeding and 30-day mortality. On multivariable analysis, BMI was not associated with stroke or perioperative mortality. MO was associated with perioperative cardiac complications (Odds Ratios [OR] 1.26, 95% CI 1-1.57, P = 0.05). UW status was associated with increased return to the operating room (OR 1.89, 95% confidence interval [95% CI] 1.28-2.78, P = 0.001), 30-day mortality (OR 1.68, 95% CI 1-2.86, P =0.05), 1-year mortality (Hazard ratio [HR] 1.37, 95% CI 1.08-1.74, P = 0.01), and 5-year mortality (HR 1.22, 95% CI 1.06-1.41, P =0.005).

CONCLUSIONS

BMI status was not associated with perioperative stroke, cranial nerve injury, or surgical site infections. Patients with MO had higher perioperative cardiac complications. UW patients have lower short and long-term survival and should be a focus for long-term targeted risk factor stratification and modification.

Underweight patients are an often under looked “At risk” population after undergoing posterior cervical spine surgery

Background

Body Mass Index (BMI) is a weight-for-height metric that is used to quantify tissue mass and weight levels. Past studies have mainly focused on the association of high BMI on spine surgery outcomes and shown variable conclusions. Prior results may have varied due to insufficient power or inconsistent categorical separation of BMI groups (e.g. underweight, overweight, or obese). Additionally, few studies have considered outcomes of patients with low BMI. The aim of the current study was to analyze patients along the entirety of the BMI spectrum and to establish specific granular BMI categories for which patients become at risk for complication and mortality following posterior cervical spine surgery.

Methods

Patients undergoing elective posterior cervical spine surgery were abstracted from the 2005–2016 National Surgical Quality Improvement Program (NSQIP) databases. Patients were aggregated into pre-established WHO BMI categories and adverse outcomes were normalized to average risk of normal-weight subjects (BMI 18.5–24.9 kg/m²). Risk-adjusted multivariate regressions were performed controlling for patient demographics and overall health.

Results

A total of 16,806 patients met inclusion criteria. Odds for adverse events for underweight patients (BMI < 18.5 kg/m²) were the highest among any category of patients along the BMI spectrum. These patients experienced increased odds of any adverse event (Odds Ratio (OR) = 1.67, p = 0.008, major adverse events (OR=2.08, p = 0.001), post-operative infection (OR = 1.95, p = 0.002), and reoperation (OR = 1.84, p = 0.020). Interestingly, none of the overweight or obese categories were found to be correlated with increased risk of adverse event categories other than super-morbidly obese patients (BMI>50.0 kg/m²) for post-operative infection (OR = 1.54, p = 0.041).

Conclusions

The current study found underweight patients to have the highest risk of adverse events after posterior cervical spine surgery. Increased pre-surgical planning and resource allocation for this population should be considered by physicians and healthcare systems, as is often already done for patients on the other end of the BMI spectrum.

Perioperative adverse events after different fusion approaches for single-level lumbar spondylosis

Background

Low back pain from lumbar spondylosis affects a large proportion of the population. In select cases, lumbar fusion may be considered. However, cohort studies have not shown clear differences in long-term outcomes between PSF, TLIF, ALIF, and AP fusion. Thus, differences in perioperative complications might affect choice between these procedures for the given diagnosis. The current study seeks to compare perioperative adverse events for patients with lumbar spondylosis treated with single-level: posterior spinal fusion (PSF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), or combined anterior and posterior lumbar fusion (AP fusion).

Methods

Patients with a diagnosis of lumbar spondylosis who underwent single-level lumbar fusion without decompression were identified in the 2010-2016 National Quality Improvement Program (NSQIP) database. Patients were categorized based on their procedure (PSF, TLIF, ALIF, or AP fusion). Unadjusted Fisher's exact and Pearson's chi-squared tests were used to compare demographics and comorbid factors. Analysis was secondarily done with propensity score matching to address potential differences in patient selection between the study cohorts.

Results

In total, 1816 patients were identified: PSF n=322, TLIF n=800, ALIF n=460, AP fusion n=234. The procedures did not have different thirty-day individual or aggregated (any, serious, minor, or infection) adverse events. Further, propensity score matched analysis also revealed no differences in individual or aggregated thirty-day perioperative events.

Conclusion

The current study demonstrates a lack of difference in thirty-day perioperative adverse events for different fusion procedures performed for lumbar spondylosis, consistent with prior longer-term outcome studies. These findings suggest that patient/surgeon preference and other factors not captured here should be considered to determine the best surgical technique for the select patients with the given diagnosis who are considered for lumbar fusion.

Summary Sentence

Using the NSQIP 2010-2016 databases, this study showed that perioperative adverse events were similar for different surgical approaches of single-level fusion for single-level lumbar spondylosis.