Does Obesity Correlate with Postoperative Complications After Elective Posterior Cervical Spine Fusion?

Obesity is an independent risk factor for postoperative pulmonary embolism after anterior cervical discectomy and fusion

BACKGROUND

Over the past decade, the prevalence of obesity has risen in the United States, in parallel with the demand for anterior cervical discectomy with fusion (ACDF). Prior studies have evaluated the role of obesity classes in cervical spine surgery in smaller patient populations. We aimed to evaluate any potential correlation to a national population sample by utilizing a large multicenter database.

PURPOSE

The purpose of this study was to analyze obesity level's influence on perioperative complication rates in patients undergoing ACDF.

STUDY DESIGN/SETTING

A retrospective cohort, large multicenter database study.

PATIENT SAMPLE

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to identify patients who had undergone an elective ACDF procedure between 2011 and 2020 using Current Procedural Terminology (CPT) code 22551.

OUTCOME MEASURES

Medical and surgical complications within thirty days of operation.

METHODS

Patients were categorized into four BMI groups: nonobese (BMI 18.5-29.9 kg/m2), obese class I (BMI 30-34.9 kg/m2), obese class II (BMI 35-39.9 kg/m2), and obese class III (BMI ≥40 kg/m2). A univariate analysis conducted for demographic variables and preoperative comorbidities identified age, sex, race, smoking status, hypertension requiring medication, diabetes, history of congestive heart failure, history of bleeding disorder, and chronic obstructive pulmonary disease as risk factors. Chi-square test was used to compare incidence of complications among groups. A multivariable logistic regression analysis was subsequently performed to adjust for these preoperative risk factors and compare obesity classes I-III to nonobese patients.

RESULTS

About 64,718 patients were identified of whom 33,365 were nonobese, 17,190 were obese class I, 8,608 were obese class II, and 5,555 were obese class III. Obese classes I-III patients had a higher incidence of surgical site infections (0. 33%, 0.36%, 0.41%, vs. 0.24%, p=.039) and pulmonary embolism (PE) (0.25%, 0.31, 0.29 vs. 0.15%, p=.003). Obese classes I-III had a lower incidence of blood transfusion (0.23%, 0.17%, 0.27% vs. 0.4%, p<.001) obese class I, obese class II, and obese class III independently increased the risk for PE (OR: 1.716, 95% CI (1.129-2.599); OR: 2.213, 95% CI (1.349-3.559); OR: 2.207, 95% CI (1.190--3.892), respectively).

CONCLUSIONS

Risk for postoperative PEs after an ACDF was significantly higher for obese classes I-III compared to nonobese patients. These findings may further support the use of additional prophylaxis measures and precaution in the perioperative setting.

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.

Incidence and risk factors of surgical site infection following cervical laminoplasty: A retrospective clinical study

There are many debates regarding the risk factors of surgical site infection (SSI) following posterior cervical surgery in previous studies. And, till now there is no such a study to examine cervical laminoplasty surgery. From January 2011 through October 2021, a total of 405 patients who were treated with unilateral open-door laminoplasty surgeries were enrolled in this study. We divided the patients into the SSI group and the non-SSI group and compared their patient-specific and procedure-specific factors. Univariate and multiple logistic regression analysis were performed to determine the risk factors. Of the 405 patients, 20 patients had SSI. The rate of SSI found to be 4.93%. There were significant differences between groups in the thicker subcutaneous fat thickness (FT) (p < 0.001), the higher ratio of subcutaneous FT to muscle thickness (MT) (p < 0.001), the higher preoperative Japanese Orthopaedic Association (JOA) Scores (p < 0.003), the decreased preoperative serum albumin (p < 0.001), the more postoperative drainage (p < 0.05) and the longer time of draining (p < 0.001). Logistic regression analysis of these differences showed that the higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining were significantly related to SSI (p < 0.05). The higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining are identified as the independent risk factors of SSI in cervical laminoplasty. Identification of these risk factors could be useful in reducing the SSI incidence and patients counselling.

Use of random forest machine learning algorithm to predict short term outcomes following posterior cervical decompression with instrumented fusion

Random Forest (RF) is a widely used machine learning algorithm that can be utilized for identification of patient characteristics important for outcome prediction. Posterior cervical decompression with instrumented fusion (PCDF) is a procedure for the management of cervical spondylosis, cervical spinal stenosis, and degenerative disorders that can cause cervical myelopathy or radiculopathy. An RF algorithm was employed to predict and describe length of stay (LOS), readmission, reoperation, transfusion, and infection rates following elective PCDF using The American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database 2008 through 2018. The RF algorithm was tasked with determining the importance of independent clinical variables in predicting our outcomes of interest and importance of each variable based on the reduction in the Gini index. Application of an RF algorithm to the ACS-NSQIP database yielded a highly predictive set of patient characteristics and perioperative events for five outcomes of interest related to elective PCDF. These variables included postoperative infection, increased age, BMI, operative time, and LOS, and decreased preoperative hematocrit and white blood cell count. Risk factors that were predictive for rate of reoperation, readmission, hospital length of stay, transfusion requirement, and post-operative infection were identified with AUC values of 0.781, 0.791, 0.781, 0.902, and 0.724 respectively. Utilization of these findings may assist in risk analysis during the perioperative period and may influence clinical or surgical decision-making.

Obesity and Spine Surgery: A Qualitative Review About Outcomes and Complications. Is It Time for New Perspectives on Future Researches?

STUDY DESIGN

Literature review.

OBJECTIVES

An increasing number of obese patients requires operative care for degenerative spinal disorders. The aim of this review is to analyze the available evidence regarding the role of obesity on outcomes after spine surgery. Peri-operative complications and clinical results are evaluated for both cervical and lumbar surgery. Furthermore, the contribution of MIS techniques for lumbar surgery to play a role in reducing risks has been analyzed.

METHODS

Only articles published in English in the last 10 years were reviewed. Inclusion criteria of the references were based on the scope of this review, according to PRISMA guidelines. Moreover, only paper analyzing obesity-related complications in spine surgery have been selected and thoroughly reviewed. Each article was classified according to its rating of evidence using the Sacket Grading System.

RESULTS

A total number of 1636 articles were found, but only 130 of them were considered to be relevant after thorough evaluation and according to PRISMA checklist. The majority of the included papers were classified according to the Sacket Grading System as Level 2 (Retrospective Studies).

CONCLUSION

Evidence suggest that obese patients could benefit from spine surgery and outcomes be satisfactory. A higher rate of peri-operative complications is reported among obese patients, especially in posterior approaches. The use of MIS techniques plays a key role in order to reduce surgical risks. Further studies should evaluate the role of multidisciplinary counseling between spine surgeons, nutritionists and bariatric surgeons, in order to plan proper weight loss before elective spine surgery.

Cervical alignment in the obese population following posterior cervical fusion for cervical myelopathy

STUDY DESIGN

Retrospective cohort study OBJECTIVE: The aim of this study was to investigate the effect of body mass index (BMI) on the reoperation rate and cervical sagittal alignment of patients who underwent posterior cervical decompression and fusion for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Cervical sagittal balance has been correlated with postoperative clinical outcomes. Previous studies have shown worse postoperative sagittal alignment and higher reoperation rates in patients with high BMI undergoing anterior decompression and fusion. Similar evidence for the impact of obesity in postoperative sagittal alignment for patients with (CSM) undergoing posterior cervical decompression and fusion (PCF) is lacking.

METHODS

A retrospective analysis of 198 patients who underwent PCF for cervical myelopathy due to degenerative spine disease was performed. Demographics, need for reoperation, and perioperative radiographic parameters were collected. Cervical lordosis (CL), C2-7 sagittal vertical axis (SVA), and T1 slope (T1S) was measured on standing lateral radiographs. Comparative analysis of the patient cohort was performed by stratifying the sample population into three BMI categories (<25, 25-30, ≥30).

RESULT

Of the 198 patients that met inclusion criteria, 53 had BMI normal (<25), 65 were overweight (25-30), and 80 were obese (≥30). Mean SVA increased postoperatively in all groups, 4 mm in the normal group, 13 mm in the overweight group, and 13 mm in the obese group (p = 0.003). There was no significant difference in the postoperative change of cervical lordosis or T1 slope between the groups. Multivariate analysis demonstrated fusions involving the cervicothoracic junction and those involving 5 or more levels significantly affected alignment parameters. There were 27 complications requiring reoperation (14%) with no significant differences among the groups stratified by BMI (p = 0.386).

CONCLUSIONS

Overweight patients (BMI>25) with CSM undergoing PCF had a greater increase in SVA than normal weight patients while reoperation rates were similar. In addition, preoperative CL increased with increasing BMI, although this trend was not Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation significant and there was not found to be a significant difference between the change in CL from baseline to post-fusion between BMI cohorts. This study further highlights the importance of considering BMI when attempting to optimize sagittal alignment in patients undergoing PCF.