Critical care of obese patients during and after spine surgery

A prospective cohort study of the accuracy and safety of robot-assisted minimally invasive spinal surgery

Background

Robot-assisted open surgery (RA-OS) is now commonly used in traditional open-exposure spinal screw placement surgery. With the help of robots, robot-assisted minimally invasive surgery (RA-MIS) can achieve less bleeding and less tissue damage in percutaneous screw insertion. While the research comparing the safety and accuracy of screw placement between RA-MIS and RA-OS is insufficient. This study aims to compare the effects of RA-MIS and RA-OS in thoracic and lumbar spine.

Methods

This was a prospective cohort study evaluating 208 patients undergoing robot-assisted screw insertions from July 2020 to September 2021. Age, BMI, gender, screws accuracy, screws Gertzbein–Robbins grade, small joint invasion and perioperative outcomes (operation time, blood loss, postoperative hospital stay, comorbidity) were collected. A subgroup analysis was also performed according to disease, namely fracture, spondylolisthesis, and disc herniation. Data were analyzed using Stata/MP 14.0. Wilcoxon’s signed rank test, Kruskal–Wallis test and Fisher’s exact test were used for statistical tests and p < 0.05 was considered statistically significant.

Results

A total of 1030 screws were inserted; 368 minimally invasive screws and 662 open screws. The acceptability of screw insertion in the RA-MIS and RA-OS was 97.3% and 95.6% respectively. There was no statistical difference between the RA-MIS group and RA-OS group in age (p = 0.106), gender (p = 0.074), BMI (p = 0.181) and comorbidity (p = 0.203). Compared with RA-OS, RA-MIS had less blood loss (p < 0.001) and shorter postoperative hospital stay (p = 0.008). In the minimally invasive surgery group, the fracture subgroup had smaller screw deviation, less blood loss, and shorter operation time compared with the other subgroups (p < 0.01). Specifically, RA-MIS significantly reduced the postoperative hospital stay of patients with spondylolisthesis compared with RA-OS (p < 0.01).

Conclusion

RA-OS and RA-MIS had equal accuracy and safety. Compared with open surgery, minimally invasive surgery reduced blood loss in each subgroup and shortened the postoperative hospital stay in the spondylolisthesis subgroup. Compared with the other subgroups under minimally invasive surgery, the fracture subgroup had less blood loss and shorter operation time.

Clinical trial registration: NCT04040868. Registered 1 March 2019, https://clinicaltrials.gov/ct2/show/NCT04040868?cond=Accuracy+Study+of+Robot-assisted+Screw+Insertion+in+Spinal+Surgery&draw=2&rank=1.

The predictive accuracy of surgical planning using pre-op planning software and a robotic guidance system

BACKGROUND

Navigation and robotic-guided systems are being used more often to facilitate efficient and accurate placement of hardware during spinal surgeries. Preoperative surgical planning is a key step in the safe use of these tools. No studies have yet investigated the predictive accuracy of surgical planning using a robotic guidance system.

METHODS

Data were prospectively collected from patients in whom Mazor X-Align ™ [Medtronic Inc., Minneapolis, MN., USA] robotic guidance system software was used to plan their spinal instrumentation in order to achieve the best possible correction and the plans executed intraoperatively under robotic guidance.

RESULTS

A total of 33 patients (26 females, 7 males) were included. Their mean age was 51 years (12-79), and their mean BMI was 23.90 (15.55-35.91). Their primary diagnoses were scoliosis (20), kyphosis (5), spondylolisthesis (4), adjacent segment degeneration (3), and metastatic tumor (1). Preoperatively, the patients' mean coronal Cobb Angle (CA) was 36.5 ± 14.4°, and their mean sagittal CA was 27.7 ± 20.0°. The mean planned correction coronal CA was 0.2 ± 1.2°, and the mean planned correction sagittal CA was 28.4 ± 16.7°. Postoperatively, the patients' mean coronal CA that was achieved was 5.8 ± 7.4°, and their mean sagittal CA was 31.0 ± 18.3°. The mean difference between the planned and achieved angles was 5.5 ± 7.4° for the coronal, and 9.03 ± 9.01° for the sagittal CA. For the thoracic kyphosis and lumbar lordosis, the mean difference between the planned and postoperatively measured values was 15.3 ± 10.8 and 12.8 ± 9.6, respectively.

CONCLUSION

This study indicates that the predictive accuracy of the use of preoperative planning software and robotic guidance to facilitate the surgical plan is within 6° and 9° in the coronal and sagittal planes, respectively.

Discharge Disposition and Clinical Outcomes After Spine Surgery

OBJECTIVE

Spinal decompression with or without fusion is one of the most commonly performed procedures in spine surgery. However, there is limited evidence on the effect of discharge environment on outcomes after surgery. The purpose of this study is to identify the effects of discharge disposition setting on clinical outcomes after spine surgery.

METHODS

Patients who underwent lumbar decompression, lumbar decompression and fusion, or posterior cervical decompression and fusion surgery were retrospectively identified. All clinical and demographic data were obtained from electronic health records. Surgical outcomes included wound complications, revision surgery, "30-day" readmission (0-30 d), and "90-day" readmission (31-90 d). Discharge disposition was stratified into home/self-care, acute inpatient rehabilitation, and subacute rehabilitation. Patient-reported outcome measures including VAS Back, VAS Leg, VAS Neck, VAS Arm, PCS-12 and MCS-12, ODI, and NDI were compared between patient discharge disposition settings using the Mann-Whitney U test. Pearson's chi-square analysis was used to assess for differences in wound complications, revision surgery, 30-day readmission, or 90-day readmission rates. Multivariate logistic regression incorporating age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), and discharge disposition was used to determine independent predictors of wound complications.

RESULTS

A total of 637 patients were included in the study. A significant difference (P = 0.03) was found in wound complication based on discharge disposition, with subacute disposition having the highest proportion of wound complications (6.1%) and home disposition having the lowest (1.5%). There were no significant differences in the rates of revision surgery, 30-day readmission, or 90-day readmission between groups. Subacute rehabilitation (odds ratio: 3.67, P = 0.047) and CCI (odds ratio 1.49, P = 0.01) were independent predictors of wound complications. Significant improvement in PROMs was seen across all postacute discharge dispositions. Baseline (P = 0.02) and postoperative (P = 0.02) ODI were significantly higher among patients discharged to an acute facility (49.4 and 32.0, respectively) compared to home (42.2 and 20.0) or subacute (47.4 and 28.4) environments.

CONCLUSION

Subacute rehabilitation disposition and CCI are independent predictors of wound complications after spinal decompression surgery. Patients undergoing spine surgery have similar readmission and revision rates and experience similar clinical improvement across all postacute discharge dispositions.

Intraoperative neurophysiological monitoring of T9-T10 fracture in a patient with morbid obesity and ankylosing spondylitis: A case report with literature review

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Obese patients have elevated risk of perioperative injury during spine surgery.

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IONM identified true-positive changes from unexpected worsening of spinal fracture.

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IONM changed the course of the surgery and prevented further injury to the patient.

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Need more research on using IONM in spine surgery with morbidly obese patients.

Introduction

As the prevalence of obesity continues to rise, there is a growing need to identify practices that protect overweight patients from injury during spine surgery. Intraoperative neurophysiological monitoring (IONM) has been recommended for complex spine surgery, but its use in obese and morbidly obese patients is understudied.

Case report

This case report describes a patient with morbid obesity and ankylosing spondylitis who was treated for a T9-T10 3-column fracture with a planned, minimally invasive approach. Forty minutes after positioning the patient to prone, the IONM team identified a positive change in the patient’s motor responses in the bilateral lower extremities and alerted the surgical team in a timely manner. It turned out that the pressure exerted by gravity on the patient’s large pannus resulted in further dislocation of the fracture and narrowing of the spinal canal. The surgical team acknowledged the serious risk of spinal cord compression and, hence, immediately changed the surgical plan to an urgent, open approach for decompression and reduction of the fracture. The patient’s lower extremities’ motor responses improved after decompression. The patient was ambulatory on post-operative day 2 and pain-free at six-weeks with no other neurologic symptoms.

Significance

The use of IONM in this planned minimally invasive spine surgery for a patient with morbid obesity prevented potentially serious iatrogenic injury. The authors include a literature review that situates this case study in the existing literature and highlights a gap in current knowledge. There are few studies that have examined the use of IONM during spine surgery for morbidly obese patients. More research is needed to elucidate best practices for the use of IONM in spine surgery for morbidly obese patients.

Are the Outcomes of Minimally Invasive Transforaminal/Posterior Lumbar Fusion Influenced by the Patient's Age or BMI?

STUDY DESIGN

A retrospective subgroup analysis of a prospective observational study was carried out.

SUMMARY OF BACKGROUND DATA

Patients' baseline characteristics may influence the clinical outcomes after minimally invasive lumbar interbody fusion (MILIF).

OBJECTIVE

This study aimed to investigate the influence of patient's age and body mass index (BMI) on the clinical outcomes of MILIF for degenerative lumbar disorder.

MATERIALS AND METHODS

A total of 252 patients underwent MILIF. The clinical outcomes, including time to first ambulation, time to postsurgical recovery, back/leg pain in visual analog scale, Oswestry Disability Index, and EuroQol-5 Dimension, were collected at baseline, 4 weeks, 6, and 12 months. Patients were subgrouped by age (50 y and below: N=102; 51-64 y: N=102; 65 y and above: N=48) and BMI (≤25.0: N=79; 25.1-29.9: N=104; ≥30.0: N=69). Data from baseline to 12 months were compared for all clinical outcomes within age/BMI subgroups. Adverse events (AEs) and serious adverse events (SAEs) were summarized by age and BMI subgroups.

RESULTS

All age and BMI subgroups showed significant improvements in clinical outcomes at 12 months compared with the baseline. The median time to first ambulation was similar for all subgroups (age groups: P=0.8707; BMI: P=0.1013); older people show a trend of having longer time to postsurgical recovery (age groups: P=0.0662; BMI: P=0.1591). Oswestry Disability Index, back, and leg pain visual analog scale, and EuroQol-5 Dimension were similar in all subgroups at every timepoint. A total of 50 AEs (N=39) were reported, 9 of which were SAEs; 3 AEs and 1 SAE were considered to be related to surgical procedure. No differences were observed in safety by age groups and BMI groups.

CONCLUSION

MILIF appears to be safe and effective, independent of age or weight in the treatment of degenerative lumbar disorder.

LEVEL OF EVIDENCE

Level II.

Intervention to reduce the incidence of surgical site infection in spine surgery

BACKGROUND

This study examines the incidence, characteristics, and risk factors of surgical site infections (SSIs) after spine surgery and evaluates the efficacy of a preventive intervention.

METHODS

This was a quasi-experimental pretest/posttest study in patients undergoing spinal surgery in an orthopedic surgery department from December 2014 to November 2016. Based on the results of the study, we revised the preventive protocol with modification of wound dressing, staff training, and feedback. SSI rates were compared between the pre-intervention (December 2014 to November 2015) and post-intervention (December 2015 to November 2016) periods. The risk factors were analyzed using univariate and multivariate analyses.

RESULTS

Of the 139 patients included, 14 cases of SSI were diagnosed, with a significant decrease in the incidence of SSIs from the pre-intervention period to the post-intervention period (19.4% vs 2.6%; P = .001). The etiology was known in 13 cases, with enteric flora being predominant in the pre-intervention group. Univariate analysis showed that age, body mass index, days until sitting and ambulation, and incontinence were statistically significant risk factors. After multivariate analysis, only body mass index and days until ambulation remained significant. When the effect of intervention was adjusted with other risk factors, this variable remained statistically significant.

CONCLUSIONS

An intervention that includes modification of wound dressing and early mobilization, as well as staff awareness training, monitoring, and feedback, allowed a significant reduction in the incidence of SSI following spinal surgery, particularly infections caused by enteric flora.

Postoperative Supine Position Increases the Risk of Infection After Spinal Surgery by Posterior Approach

BACKGROUND

Spine surgeries performed via the posterior approach have a higher infection rate. Several theories have been proposed, including poor hygienic condition of bed sheets and traumatized muscle associated with supine position promoting circulatory impairment. We investigated the influence of supine position on the rate of deep wound infection after spine surgery by the posterior approach.

METHODS

A total of 106 patients were randomly divided into 2 groups: lateral decubitus only versus dorsal and lateral decubitus. Patient follow-up after hospital discharge was performed at 30, 60, 180, and 360 days. Deep wound infection was diagnosed according to U.S. Centers for Disease Control and Prevention criteria.

RESULTS

Patient sample was mainly composed of patients with neoplastic disease and patients with trauma. Postoperative wound infection developed in 12 cases (11.3%), and Streptococcus aureus was the most common pathogen. Incidence of postsurgical deep wound infection was significantly greater in the control group (P = 0.004).

CONCLUSIONS

Supine position was significantly correlated with higher rates of wound infection among patients who underwent spine surgery by the posterior approach. Avoidance of supine position may represent a modifiable risk factor to diminish postoperative spine infection rates.

Risk Factors for Perioperative Complications in Morbidly Obese Patients Undergoing Elective Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The prevalence of obesity-related low back pain and degenerative disc disease is on the rise. Past studies have demonstrated that obesity is associated with higher perioperative complication rates, but there remains a gap in the literature regarding additional risk factors that further predispose this already high-risk patient population to poor surgical outcomes following elective posterior lumbar fusion (PLF). The aim of the study is to identify independent risk factors for poor 30-day perioperative outcomes in morbidly obese patients undergoing elective PLF.

METHODS

We identified 22 909 patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent elective PLF. There were 1861 morbidly obese patients. Baseline patient demographics and medical comorbidities were collected. Univariate analysis was performed to compare perioperative complication rates between non-morbidly obese and morbidly obese patients. The 5 most common complications in the morbidly obese group were then selected for multivariate regression analysis to identify independent risk factors for poor 30-day outcomes.

RESULTS

Morbidly obese patients had a higher perioperative complication rate. The 5 most common complications were prolonged hospitalization, blood transfusion, readmission, wound complications, and reoperation. Independent risk factors for these complications were age ≥65 years, super obesity (ie, BMI > 48.6), chronic steroid use, American Society of Anesthesiology classification ≥3, poor functional status, long length of fusion ≥4 levels, and extended operative time (ie, operative time ≥318 minutes).

CONCLUSIONS

Morbidly obese patients are at higher risk of perioperative complications following elective PLF. Modifiable risk factors for the most common complications are obesity and preoperative steroid use.

Increasing Body Mass Index is Associated With Worse Perioperative Outcomes and Higher Costs in Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVE

To investigate associations of obesity with outcomes and costs of adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Increasing body mass index (BMI) is a risk factor for complications after nondeformity spine surgery, but its effect on ASD surgery is unknown.

METHODS

We reviewed records of 244 ASD patients who underwent spinal arthrodesis of ≥5 levels from 2010 to 2014 and categorized them by World Health Organization BMI groups: BMI < 30, nonobese (64%); BMI = 30-34.99, class-I obese (21%); and BMI ≥ 35, class-II/III obese (15%). We used multivariate logistical regression to determine odds of transfusion, inpatient complications, prolonged intensive care unit (ICU) stay (>2 days), prolonged total length of hospital stay (LOS) (>1 week), and high episode-of-care costs (>$80,000).

RESULTS

Preoperative characteristics were similar among groups, except sex, preoperative hemoglobin concentration, and performance/type of osteotomy (all, P = 0.01). On univariate analysis, the groups differed in rates of prolonged ICU stay (P < 0.001), prolonged total LOS (P = 0.016), and high episode-of-care costs (P = 0.013). Inpatient complication rates were similar among groups (P = 0.218). On multivariate analysis, compared with nonobese patients, class I obese patients had greater odds of prolonged ICU stay (odds ratio [OR] = 2.24, 95% confidence interval [CI]: 1.06, 4.71). Class II/III obese patients also had greater odds of prolonged total LOS (OR = 2.21, 95% CI: 1.03, 4.71), and high episode-of-care costs (OR = 2.91, 95% CI: 1.31, 6.50).

CONCLUSION

In ASD surgery, BMI ≥35 is associated with significantly worse perioperative outcomes and higher costs compared with those of nonobese patients.

LEVEL OF EVIDENCE

3.

[Impact of obesity in the pathophysiology of degenerative disk disease and in the morbidity and outcome of lumbar spine surgery]

Obesity (BMI>30Kg/m²) is a pandemic with severe medical and financial implications. There is growing evidence that relates certain metabolic processes within the adipose tissue, preferentially abdominal fat, with a low-intensity chronic inflammatory state mediated by adipokines and other substances that favor disk disease and chronic low back pain. Obesity greatly conditions both the preoperative evaluation and the spinal surgical technique itself. Some meta-analyses have confirmed an increase of complications following lumbar spine surgery (mainly infections and venous thrombosis) in obese subjects. However, functional outcomes after lumbar spine surgery are favorable although inferior to the non-obese population, acknowledging that obese patients present with worse baseline function levels and the prognosis of conservatively treated obese cohorts is much worse. The impact of preoperative weight loss in spine surgery has not been prospectively studied in these patients.

Factors Associated with Patient-Initiated Telephone Calls After Spine Surgery

BACKGROUND

Telephone calls play a significant role in the follow-up care of postoperative patients. However, further data are needed to identify the determinants of patient-initiated telephone calls after surgery because these factors may also highlight potential areas of improvement in patient satisfaction and during the hospital discharge process. Therefore, the goal of this study is to determine the number of postoperative patient telephone calls within 14 days after surgery and establish the factors associated with patient-initiated calls and reasons for calling.

METHODS

A retrospective chart review of all spine surgeries performed at our institution from January 1, 2014, through January 2, 2015, was completed. Patient demographics, perioperative and operative variables, and telephone encounter data were collected. The primary outcome was a patient-initiated telephone call within 14 days after surgery. Secondary outcomes included reporting and analyzing the reasons for patient phone calls, analyzing which procedures were associated with the most telephone calls, and conducting a multivariate analysis to determine independent risk factors for patient calls.

RESULTS

Of the 488 patients who underwent surgical procedures, 222 patients (45.7%) made a telephone call within 14 days after surgery. There were 61 patients (27.48%) who called regarding pain control and 54 patients (23.87%) who called with bathing/dressing/wound questions. Other common categories include the following: other (21.17%), medication problems (15.77%), weight-bearing status/activity restrictions (5.14%), fever (3.15%), bowel management (1.35%), work notes (1.35%), and anticoagulation questions (0.45%). Factors associated with a telephone call within 14 days postoperatively included increased body mass index (P = 0.031), lower number of comorbidities (P = 0.043), telephone call within 2 weeks prior to surgery (P = 0.027), American Society of Anesthesiologists (ASA) score of 2 (P = 0.036), discharge disposition to home (P = 0.003), and elective procedure (P = 0.006). Multivariate analysis revealed that fusion procedures (odds ratio [OR], 2.16; 95% confidence interval [CI], 1.05-4.45; P = 0.037) and ASA score of 3-4 (OR, 0.55; 95% CI, 0.31-0.96, P = 0.036) were independently associated with increased and decreased propensity, respectively, toward making a phone call within 2 weeks.

CONCLUSIONS

Postoperative patient-initiated telephone calls within 14 days after spine surgery are very common, occurring after almost one half of all procedures. By evaluating such determinants, patient care can be improved by better addressing patient needs during and prior to discharge to prevent potential unnecessary postoperative calls and improve patient satisfaction.