Body mass index and risk of surgical site infection following spine surgery: a meta-analysis

Determining the normative reference values for acute-phase inflammatory markers 3 days after lumbar fusion surgery by using the e-norms method

BACKGROUND CONTEXT

Surgical site infection (SSI) is a devastating complication that greatly increases the duration of hospital stays, health care costs and morbidity/mortality rates. Therefore, early diagnosis and treatment are also very important. Postoperative inflammatory markers are usually used to screen for SSI. However, the feasibility of these markers for the early detection of SSI remains unclear since it is not ideal to use a marker for which normative reference values do not exist.

PURPOSE

To validate the use of the e-norms method for establishing a normative reference range for acute-phase inflammatory marker levels 3 days after lumbar fusion surgery for early screening of postoperative SSI.

STUDY DESIGN

A retrospective analysis.

PATIENT SAMPLE

This study included 907 patients who underwent lumbar fusion surgery (SSI vs non-SSI: 28 vs 879).

OUTCOME MEASURES

White blood cell (WBC) count, neutrophils count, lymphocyte count, C-reactive protein (CRP) and Erythrocyte sedimentation rate (ESR).

METHODS

We applied the e-norms method to calculate reference values for postoperative 3-day CRP, ESR, and differential WBC count in all 907 patients included in this study and compared these reference values with those calculated via conventional methods (data from non-SSI patients).

RESULTS

According to the e-norms method, the normal WBC count was 10.8±1.2 (x10^9/L), neutrophils count was 8.7±1.1 (x10^9/L), lymphocyte count was 1.6±0.3 (x10^9/L), CRP concentration was 31.2±10.8 mg/L, and ESR was 23.6±4.7 mm/h. The mean values obtained via the e-norms and conventional methods were almost identical, but the range of normative reference values obtained via the conventional methods was relatively wider. Importantly, the frequency of SSI patients with abnormal inflammatory markers identified by the e-norms method was higher than that of patients with abnormal inflammatory markers identified by the conventional methods (21/28, 75.0% vs 6/28, 21.4%; p<.05).

CONCLUSIONS

The results of this study demonstrated that the reference values retrieved using e-norms were more effective for screening postoperative SSI than the reference values calculated using conventional methods. Thus, e-norms may be an alternative reliable and time-saving approach to establishing reference values for acute-phase inflammatory markers after spinal surgery.

The neutrophil-to-lymphocyte ratio (NLR) levels predicting the surgical site infection in spinal surgery: a systematic review

Background

Surgical site infection (SSI) is a prevalent complication in spinal surgery, associated with significant morbidity, prolonged hospital stays, and increased healthcare costs. The early detection of SSI can lead to timely intervention. Among available diagnostic methods, the neutrophil-to-lymphocyte ratio (NLR) has emerged as a simple, accessible marker with potential predictive value for SSIs. This systematic review aims to evaluate the diagnostic role of NLR, in the early detection of SSIs following spinal surgery.

Methods

Following PRISMA guidelines, we conducted a comprehensive literature search in MEDLINE, Web of Science, Embase, and Scopus databases for studies examining the utility of NLR in predicting SSIs in all types of spinal surgery patients. Ultimately, 7 studies met the inclusion criteria; all retrospective in design, with sample sizes ranging from 77 to 384. Studies focused on NLR values measured at different postoperative days, solely or along with some integrating additional markers, including C-reactive protein (CRP) and body mass index (BMI), into predictive models.

Results

Our study confirmed that NLR serves as a significant predictor of SSIs post-spinal surgery. Analyses of included studies revealed variable optimal NLR cutoff values, ranging from 3.21 to 4.91, dependent on postoperative day and surgery type. The highest predictive accuracy was observed when NLR was combined with CRP and lymphocyte percentage, enhancing early SSI detection. However, the variability in cutoff values and measurement timing across studies suggests limitations due to heterogeneity in study designs and patient populations, indicating the need for further research to establish standardized protocols.

Conclusions

NLR could be of value for early SSI detection in spinal surgery, with its diagnostic accuracy potentially improved by combining it with other markers. However, variability in cutoff values and timing across studies suggests the need for further research to standardize these parameters. Establishing consistent protocols could improve SSI detection, enabling faster interventions and potentially enhancing patient outcomes in spinal surgery.

Comparison of Outcomes Between Staged and Same-Day Circumferential Spinal Fusion for Adult Spinal Deformity: Systematic Review and Meta-Analysis

BACKGROUND

Adult spinal deformity (ASD) is a prevalent condition often treated with circumferential spinal fusion (CF), which can be performed as staged or same-day procedures. However, evidence guiding the choice between these approaches is lacking.

OBJECTIVE

This study aims to compare patient outcomes following staged and same-day CF for ASD.

METHODS

Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a comprehensive literature search was conducted in PubMed, MEDLINE, Embase, Cochrane CENTRAL, Web of Science, and Scopus. Eligibility criteria included studies comparing outcomes following staged and same-day CF in adults with ASD. Searches were exported to Covidence, and records were deduplicated automatically. Title and abstract screening, full-text review, and data extraction were performed by two independent reviewers, with all conflicts being resolved by a third reviewer. A meta-analysis was conducted for outcomes reported in 3 or more studies.

RESULTS

Seven studies with 741 patients undergoing CF for ASD were included in the review (staged: n=331, 44.7% and same-day: n=410, 55.3%). Four studies that had comparable outcomes were merged for the quantitative meta-analysis and split based on observed measures. The meta-analysis revealed significantly shorter hospital length of stay (mean difference 3.98, 95% CI 2.23-5.72 days; P<.001) for same-day CF. Three studies compared the operative time between staged and same-day CF, with all reporting a lower mean operative time for same-day CF (mean between 291-479, SD 129 minutes) compared to staged CF (mean between 426-541, SD 124 minutes); however, inconsistent reporting of mean and SD made quantitative analyses unattainable. Of the 4 studies that compared estimated blood loss (EBL) in the relevant groups, 3 presented a lower EBL (mean between 412-1127, SD 954 mL) in same-day surgery compared to staged surgery (mean between 642, SD 550 to 1351, SD 869 mL). Both studies that reported intra- and postoperative adverse events showed more intraoperative adverse events in staged CF (10.9% and 13.6%, respectively) compared to same-day CF (9.1% and 3.6%, respectively). Four studies measuring any perioperative adverse events showed a higher incidence of adverse events in staged CF than all studies combined. However, quantitative analysis of EBL, intraoperative adverse events, and perioperative adverse events found no statistically significant difference. Postoperative adverse events, reoperation, infection rates, and readmission rates showed inconsistent findings between studies. Data quality assessment revealed a moderate degree of bias for all included studies.

CONCLUSIONS

Same-day CF may offer shorter operating time and hospital stay compared to staged CF for ASD. However, there was marked heterogeneity in perioperative outcomes reporting, and continuous variables were inconsistently presented. This underscored the need for standardized reporting of clinical variables and patient-reported outcomes and higher evidence of randomized controlled trials to elucidate the clinical superiority of either approach.

TRIAL REGISTRATION

PROSPERO CRD42022339764; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=339764.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/42331.

Intraoperative Hypotension Is an Important Modifiable Risk Factor for Major Complications in Spinal Fusion Surgery

STUDY DESIGN

Retrospective observational cohort.

OBJECTIVES

This study explores the impact of Intraoperative hypotension (IOH) on postoperative complications for major thoracolumbar spine fusion procedures.

SUMMARY OF BACKGROUND DATA

IOH with mean arterial pressure (MAP) <65 mm Hg is associated with postoperative acute kidney injury (AKI) in general surgery. In spinal deformity surgery, IOH is a contributing factor to MEP changes and spinal cord dysfunction with deformity correction.

METHODS

A total of 539 thoracolumbar fusion cases, more than six surgical levels and >3 hours duration, were identified. Anesthetic/surgical data included OR time, fluid volume, blood loss, blood product replacement and use of vasopressors. Arterial-line based MAP data was collected at 1-minute intervals. Cummulative duration of MAP <65 mm Hg was recorded. IOH within the first hour of surgery vs. the entire case was determined. Post-op course and complications including SSI, GI complications, pulmonary complications, MI, DVT, PE, AKI, and encephalopathy were noted. Cumulative complications were grouped as none, one to two complications, or more than three complications.

RESULTS

There was a significant association between occurrence of complications and duration of IOH within the first hour of surgery (8.2 vs . 5.6 min, P <0.001) and across the entire procedure (28.1 vs . 19.3 min, P =0.008). This association persisted for individual major complications including SSI, acute respiratory failure, PE, ileus requiring NGT, and postoperative cognitive dysfunction. Comparison of patients with zero versus one to two versus three or more complications demonstrated that patients with three or more complications had a longer duration of IOH in the first hour of the surgery and that patients who had no complications received less vasopressor than patients who had one to two or three or more complications.

CONCLUSION

This study identifies duration of IOH during the first hour of surgery as a previously unrecognized modifiable risk associated with major complications for multilevel lumbar fusion surgery.

LEVEL OF EVIDENCE

III.

A retrospective cohort review of BMI on SI joint fusion outcomes: examining the evidence to improve insurance guidelines

PURPOSE

The demand for SIJ fusion among obese patients has grown substantially. However, the clinical relevance of obesity in the context of SI joint fusion has not been well investigated specifically, whether there is a BMI cutoff above which the benefit-risk ratio is low.

METHODS

Adult patients ≥ 21 years of age who underwent minimally invasive SIJ fusion between 2020 and 2023. Participants were classified using the National Institutes for Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects completed the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) at baseline and 12 months. One-way analysis of variance was used to examine the impact of BMI category on score changes.

RESULTS

Overall, mean VAS improved at 12 months by 2.5 points (p < .006). Over the 12-month follow-up period, BMI category did not impact mean improvement in VAS (ANOVA p = .08). Mean ODI at 12 months improved by 23.2 points (p < .001). BMI category did impact mean improvement in ODI (ANOVA p = .03).

CONCLUSION

This study demonstrates similar benefits across all BMI categories. This data suggests that obese patients do benefit from minimally invasive SIJ fusion, specifically the 35-40 BMI cohort of patients, and should not be denied this procedure based on arbitrary healthcare organizations BMI criteria.

Risk Factors Analysis and Nomogram Conduction for Major Adverse Events After Lumbar Fusion Surgery in Older Patients: A Prospective Cohort Study

OBJECTIVE

This study aimed to identify risk factors for major adverse events (AEs) after lumbar fusion surgery in patients aged 75 and older and evaluate the role of several common geriatric comprehensive assessment items in predicting postoperative major AEs.

METHODS

This is a prospective cohort study of patients aged ≥75 years who underwent open lumbar fusion for degenerative spine disease from August 2019 to August 2022. The primary outcome measure was the incidence of major postoperative AEs within 90 days after surgery. Clavien-Dindo III-IV complications and unplanned readmission were defined as major AEs. Patients' characteristics, laboratory tests, assessment results, and surgery-related variables were compared between the major AEs and the nonmajor AEs groups. Multivariable logistic regression analysis was used to identify independent risk factors for major AEs. The logistic regression model was evaluated in another prospective cohort of patients from October 2022 to October 2023.

RESULTS

A total of 301 patients (mean [SD] age, 79.7 [3.5] years; 60.5% male) were included in the study. Five features, including female (OR 1.99, P=0.040), higher body mass index (OR 1.090, P=0.024), frailty (OR 2.043, P =0.032), hypoalbuminemia (OR 2.489, P=0.040), and higher Charlson comorbidity index (OR 1.397, P=0.024), were independently associated with major AEs and were selected to develop a predictive nomogram of major AEs. The area under the curve values for the development set and validation set were 0.75 and 0.71, respectively.

CONCLUSIONS

Preoperative frailty, hypoalbuminemia, female sex, greater body mass index, and higher Charlson comorbidity index grade were risk factors for 90-day major AEs after lumbar fusion surgery in older patients. The predictive nomogram that we developed using this data can enhance preoperative risk counseling and optimization for older patients.

Risk factors for deep surgical site infection following open posterior lumbar fusion: A retrospective case-control study

This study aimed to identify risk factors for deep surgical site infection (SSI) following open posterior lumbar fusion (OPLF). We retrospectively analyzed the clinical data of patients who underwent OPLF between January 2014 and December 2022. Patients were divided into SSI and non-SSI groups according to whether deep SSI occurred following OPLF. Patient's sex, age, body mass index (BMI), history of diabetes mellitus and smoking, American Society of Anesthesiologists score, surgical segment, surgical time, preoperative albumin level, local use of vancomycin, and cerebrospinal fluid (CSF) leakage were compared between the 2 groups. Univariate and multivariate logistic regression analyses were used to identify risk factors for postoperative deep SSI. The deep SSI rate was 5.0% (63/1256). Among them, age (P < .001), BMI (P = .008), surgical segment (P < .001), surgical time (P < .001), prevalence of diabetes mellitus (P = .036), and CSF leakage (P < .001) were significantly higher in the SSI group, whereas the preoperative albumin level (P < .001) and proportion of local use of vancomycin (P = .046) were significantly lower in the SSI group than those in the non-SSI group. Multivariate analysis indicated that higher age (P = .046, odds ratio [OR]: 1.036, 95% confidence interval [CI]: 1.001-1.073), BMI (P = .038, OR: 1.113, 95% CI: 1.006-1.232), lower preoperative albumin level (P = .041, OR: 0.880, 95% CI: 0.778-0.995), higher surgical segment (P = .004, OR: 2.241, 95% CI: 1.297n3.871), and CSF leakage (P = .046, OR: 2.372, 95% CI: 1.015-5.545) were risk factors, and the local use of vancomycin (P < .001, OR: 0.093, 95% CI: 0.036-0.245) was the protective factor for deep SSI following OPLF. We identified 5 risk factors (older age and BMI, lower preoperative albumin level, higher surgical segment, and CSF leakage) and 1 protective factor (local use of vancomycin powder) for deep SSI following OPLF. To address these risk and protective factors, comprehensive evaluations and recommendations should be provided to patients to reduce SSI rates.

Prophylactic PICO◊ dressing shortens wound dressing requirements post emergency laparotomy (EL-PICO◊ trial)

BACKGROUND

Surgical site infection (SSI) is a very common complication of emergency laparotomy and causes significant morbidity. The PICO◊ device delivers negative pressure wound therapy (NPWT) to closed incisions, with some studies suggesting a role for prevention of SSI in heterogenous surgical populations. We aimed to compare SSI rates between patients receiving PICO◊ versus conventional dressing post-emergency laparotomy. Secondary objectives were to observe seroma and dehiscence rates, length of stay, days on dressing and patients' wound experience.

METHODS

This double blinded randomized controlled trial was conducted in University Malaya Medical Centre between October 2019 and March 2022. Patients undergoing emergency laparotomy requiring incisions less than 35 cm were included. Statistical analysis was performed using χ2 test for categorical variables, independent T-test or Mann-Whitney U were used for parametric or non-parametric data respectively besides logistic regression. P values of < 0.05 were considered to be significant.

RESULTS

Ninety-six patients were analyzed (47 interventions, 49 controls). The duration on dressing was more consistent in the intervention arm (PICO◊) versus control arm [9.78 ± 10.20 vs 17.78 ± 16.46 days, P < 0.001]. There was a trend towards lower SSI [14.3 vs 4.3%, P = 0.09], dehiscence [27.1 vs 10.6%, P = 0.07] and seroma [40.8 vs 23.4%, P = 0.08] rates in the intervention arm but this did not reach statistical significance. Length of stay [9 (IQR: 6-14) vs 11 (IQR: 6-22.5) days, P = 0.18] was fairly similar between the two arms, but more patients were very satisfied with PICO◊ compared to the conventional dressing [80% vs 57.1%, P = 0.03].

CONCLUSION

The use of NPWT in emergency laparotomy improves patients wound care experience, and was associated with trends towards fewer wound related complications. Cost effectiveness needs to be explored in order to further validate its use in the emergency setting, especially for patients with additional risk for SSI. Trial registration National Medical Research Registry (NMRR): NMRR-20-1975-55222.

Does obesity and varying body mass index affect the clinical outcomes and safety of biportal endoscopic lumbar decompression? A comparative cohort study

BACKGROUND

Endoscopic spine surgery has recently grown in popularity due to the potential benefits of reduced pain and faster recovery time as compared to open surgery. Biportal spinal endoscopy has been successfully applied to lumbar disc herniations and lumbar spinal stenosis. Obesity is associated with increased risk of complications in spine surgery. Few prior studies have investigated the impact of obesity and associated medical comorbidities with biportal spinal endoscopy.

METHODS

This study was a prospectively collected, retrospectively analyzed comparative cohort design. Patients were divided into cohorts of normal body weight (Bone Mass Index (BMI)18.0-24.9), overweight (BMI 25.0-29.9) and obese (BMI > 30.0) as defined by the World Health Organization (WHO). Patients underwent biportal spinal endoscopy by a single surgeon at a single institution for treatment of lumbar disc herniations and lumbar spinal stenosis. Demographic data, surgical complications, and patient-reported outcomes were analyzed. Statistics were calculated amongst treatment groups using analysis of variance and chi square where appropriate. Statistical significance was determined as p < 0.05.

RESULTS

Eighty-four patients were followed. 26 (30.1%) were normal BMI, 35 (41.7%) were overweight and 23 (27.4%) were obese. Patients with increasing BMI had correspondingly greater American Society of Anesthesiologist (ASA) scores. There were no significant differences in VAS Back, VAS Leg, and ODI scores, or postoperative complications among the cohorts. There were no cases of surgical site infections in the cohort. All cohorts demonstrated significant improvement up to 1 year postoperatively.

CONCLUSIONS

This study demonstrates that obesity is not a risk factor for increased perioperative complications with biportal spinal endoscopy and has similar clinical outcomes and safety profile as compared to patients with normal BMI. Biportal spinal endoscopy is a promising alternative to traditional techniques to treat common lumbar pathology.

Use of an Antibacterial Envelope in Spinal Cord Stimulation Reduces the Rate and Severity of Iatrogenic Infections

OBJECTIVE

To examine if the use of an antibacterial envelope (TYRX) decreases the rate of postoperative infection in chronic pain patients undergoing treatment with spinal cord stimulation (SCS) involving device implantation.

METHODS

Single-center retrospective cohort study comparing postoperative infections rates in non-TYRX recipients from 2018 to 2020 with recipients of a TYRX antibacterial envelope from 2020 to 2021. Infection was registered if a patient received any form of antibiotic treatment after hospital discharge within a follow-up period of 100 days.

RESULTS

A total of 198 patients were included: 100 in the TYRX group and 98 in the non-TYRX group. There were no significant differences between the 2 groups regarding age, body mass index (BMI), smoking, diabetes, and use of immunosuppression. The overall infection rate was 5.6%. The infection rate was 4% in the TYRX group and 7.1% in the non-TYRX group (P = 0.6). However, the 4 cases of postoperative infection in the TYRX group could be effectively managed with oral antibiotics alone, whereas 6 out of the 7 patients in the non-TYRX group required intravenous antibiotics. Moreover, device explantation was necessary in 3 of these patients suggesting the event of more severe infections in the non-TYRX group (P = 0.014).

CONCLUSIONS

The TYRX antibacterial envelope displayed infection rates reducing capabilities, along with a clear tendency to reduce revision surgeries and system removals due to infections.

Effects of BMI on SI joint fusion outcomes: examining the evidence to improve insurance guidelines

BACKGROUND CONTEXT

Obesity is increasing. Previous studies have demonstrated an association between obesity and adverse events after lumbar fusion. There is limited evidence on the effect of obesity on minimally invasive SI joint fusion (SIJF) outcomes.

PURPOSE

The purpose of this study was to investigate the impact of obesity on patient-reported outcomes in patients undergoing SIJF surgery using triangular titanium implants (TTI).

STUDY DESIGN

Retrospective cohort study based on four prospective clinical trials (INSITE [NCT01681004], SIFI [NCT01640353], iMIA [NCT01741025], and SALLY [NCT03122899]).

PATIENT SAMPLE

Adult patients ≥18 years of age who underwent minimally invasive surgery (MIS) sacroiliac joint (SIJ) fusion between 2012 and 2021.

OUTCOME MEASURES

Visual analog scale (VAS Pain), Oswestry Disability Index (ODI).

METHODS

Participants were classified using the National Institutes of Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects underwent either minimally invasive SIJ fusion with TTI or nonsurgical management (INSITE and iMIA studies only). All subjects completed SIJ pain scale scores (measured with a 100-point VAS) and disability scores (measured with ODI) at baseline and at scheduled visits to 24 months. Repeated measures analysis of variance was used to examine the impact of BMI category on score changes.

RESULTS

In the SIJF group, mean SIJ pain improved at 24 months by 53.3 points (p<.0001). Over the 24-month follow-up period, BMI category did not impact mean improvement in SIJ pain scale score (repeated measures analysis of variance (ANOVA) p=.44). In the SIJF group, mean ODI at 24 months improved by 25.8 points (p<.0001). BMI category did not impact mean improvement in ODI (ANOVA p=.60). In the nonsurgical management (NSM) group, mean improvements in SIJ pain scale and ODI were clinically small (8.7 and 5.2 points, respectively) and not affected by BMI category (ANOVA p=.49 and .40).

CONCLUSION

This study demonstrates similar benefits and risks of minimally invasive SIJ fusion with TTI across all BMI categories. This analysis suggests that obese patients benefit from minimally invasive SIJ fusion and should not be denied this procedure based solely on elevated BMI.

Construct validation of machine learning for accurately predicting the risk of postoperative surgical site infection following spine surgery

BACKGROUND

This study aimed to evaluate the risk factors for machine learning (ML) algorithms in predicting postoperative surgical site infection (SSI) following spine surgery.

METHODS

This prospective cohort study included 986 patients who underwent spine surgery at Taizhou People's Hospital Affiliated to Nanjing Medical University from January 2015 to October 2022. Supervised ML algorithms included support vector machine, logistic regression, random forest, XGboost, decision tree, k-nearest neighbour, and naïve Bayes (NB), which were tested and trained to develop a predicting model. The ML model performance was evaluated from the test dataset. We gradually analysed their accuracy, sensitivity, and specificity, as well as the positive predictive value, negative predictive value, and area under the curve.

RESULTS

The rate of SSI was 9.33%. Using a backward stepwise approach, we identified that the remarkable risk factors predicting SSI in the multi-variate Cox regression analysis were age, body mass index, smoking, cerebrospinal fluid leakage, drain duration and pre-operative albumin level. Compared with other ML algorithms, the NB model had the highest performance in seven ML models, with an average area under the curve of 0.95, sensitivity of 0.78, specificity of 0.88, and accuracy of 0.87.

CONCLUSIONS

The NB model in the ML algorithm had excellent calibration and accurately predicted the risk of SSI compared with the existing models, and might serve as an important tool for the early detection and treatment of SSI following spinal infection.

Reduction of Instrumentation-Related Spine Surgical Site Infections After Optimization of Surgical Techniques. A Single Center Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Although surgical risk factors for developing spine surgical site infections (S-SSI) have been identified, the impact of such knowledge in its prevention has not been demonstrated.

METHODS

We evaluated in 500 patients undergoing spine surgery between 2011 and 2019 at Hospital 12 de Octubre the changes in S-SSI rates over time. Surgical variables independently related to S-SSI were analyzed by univariate and multivariate analysis using binary logistic regression models. A case-control sub-analysis (1:4), matched by the surgical variables identified in the overall cohort was also performed.

RESULTS

Twenty cases of S-SSI were identified (4%), with a significant decrease in the incidence rate across consecutive time periods (6.6% [2011-2014] vs .86% [2015-2019]; P-value <.0001)). Multivariate analysis identified arthrodesis involving sacral levels (odds ratio [OR]: 2.57; 95% confidence interval [95%CI]: 1.02-6.47; P-value = .044) and instrumentation over 4-8 vertebrae (OR: 2.82; 95%CI: 1.1-7.1; P-value = .027) as independent risk factors for S-SSI. The reduction in the incidence of S-SSI concurred temporally with a reduction in instrumentations involving 4-8 vertebrae (55% vs 21.8%; P-value <.0001) and sacral vertebrae (46.9% vs 24.6%; P-value <.0001) across both periods. The case-control analysis matched by these surgical variables failed to identify other factors independently related to the occurrence of S-SSI.

CONCLUSIONS

Spinal fusion of more than 4 levels and the inclusion of sacral levels were independently related to the risk of S-SSI. Optimization of surgical techniques by reducing these two types of instrumentation could significantly reduce S-SSI rates.

Role of Pre-Operative Nutrition Status on Surgical Site Infection After Posterior Lumbar Interbody Fusion: A Retrospective Study

Background: A retrospective case-control study to determine the role of pre-operative systemic and local nutritional factors on patients developing a surgical site infection (SSI) after posterior lumbar interbody fusion (PLIF). Surgical site infection after PLIF remains a substantial cause of morbidity. The literature demonstrates the prognosis of surgical patients is associated with pre-operative nutritional status that not only includes systemic nutritional factors, such as prognostic nutritional index (PNI), body mass index (BMI), and serum albumin, but also local nutritional factors, such as subcutaneous fat thickness at the surgical site, including absolute fat thickness and relative fat thickness. However, the role of pre-operative nutrition status in SSI after PLIF surgery remains unclear. Patients and Method: A retrospective review was performed on a consecutive cohort of 766 consecutive adult patients who underwent PLIF surgery for lumbar degenerative conditions between 2020 and 2021 at Second Xiangya Hospital. Previously identified risk factors as well as systemic and local nutritional factors nutritional factors were collected. Results: Among the 766 patients, 38 had post-operative SSI including 15 superficial SSI and 23 deep SSI. Univariable analysis showed that body weight, BMI, PNI, serum albumin, and relative fat thickness differed between the SSI and non-SSI groups. Multivariable logistic regression analysis showed that pre-operative PNI and relative fat thickness were independently associated with SSI after PLIF surgery. Conclusions: Lower pre-operative PNI and higher relative fat thickness are independent risk factors for developing deep SSI after PLIF.

Biportal endoscopic discectomy versus tubular microscopic discectomy for treating single-level lumbar disc herniation in obese patients: a multicenter, retrospective analysis

PURPOSE

In microscopic lumbar discectomy in obese patients, a correlation is found between the operation time and increase in estimated blood loss according to the increase in body mass index; however, no studies have investigated the outcomes of biportal endoscopic lumbar discectomy in obese patients. Therefore, this study aimed to compare the clinical and radiographic outcomes of microscopic and endoscopic discectomy in obese patients with lumbar herniated discs.

METHODS

In this multicenter, retrospective study, clinical and radiological data were compared and analyzed in 73 obese patients with a body mass index of > 30 kg/m2 who underwent microscopic or biportal endoscopic lumbar discectomy. Clinical data on the visual analog scale (VAS), Oswestry disability index (ODI), and EuroQol-5D (EQ-5D) scores were measured, and radiological data were obtained using magnetic resonance imaging (MRI).

RESULTS

This study enrolled 43 patients who underwent microscopic discectomy and 30 who underwent biportal endoscopic discectomy. The VAS, ODI, and EQ-5D scores in both groups improved after surgery compared with those before surgery, although there was no difference between the two groups. Although there was a difference in the incidence of recurrent disc herniation confirmed by MRI after surgery, no difference was found in the number of patients requiring surgery between the two groups.

CONCLUSION

In obese patients with lumbar disc herniation that was not improved with conservative treatment, no significant clinical or radiological differences in outcomes were noted between microscopic and biportal endoscopic surgery methods. In contrast, minor complications were less common in the biportal group.

Predicting deep surgical site infection in patients receiving open posterior instrumented thoracolumbar surgery: A-DOUBLE-SSI risk score - a large retrospective multicenter cohort study in China

BACKGROUND

To develop a practical prediction model to predict the risk of deep surgical site infection (SSI) in patients receiving open posterior instrumented thoracolumbar surgery.

METHODS

Data of 3419 patients in four hospitals from 1 January 2012 to 30 December 2021 were evaluated. The authors used clinical knowledge-driven, data-driven, and decision tree model to identify predictive variables of deep SSI. Forty-three candidate variables were collected, including 5 demographics, 29 preoperative, 5 intraoperative, and 4 postoperative variables. According to model performance and clinical practicability, the best model was chosen to develop a risk score. Internal validation was performed by using bootstrapping methods.

RESULTS

After open posterior instrumented thoracolumbar surgery, 158 patients (4.6%) developed deep SSI. The clinical knowledge-driven model yielded 12 predictors of deep SSI, while the data-driven and decision tree model produced 11 and 6 predictors, respectively. A knowledge-driven model, which had the best C-statistics [0.81 (95% CI: 0.78-0.85)] and superior calibration, was chosen due to its favorable model performance and clinical practicality. Moreover, 12 variables were identified in the clinical knowledge-driven model, including age, BMI, diabetes, steroid use, albumin, duration of operation, blood loss, instrumented segments, powdered vancomycin administration, duration of drainage, postoperative cerebrospinal fluid leakage, and early postoperative activities. In bootstrap internal validation, the knowledge-driven model still showed optimal C-statistics (0.79, 95% CI: 0.75-0.83) and calibration. Based on these identified predictors, a risk score for deep SSI incidence was created: the A-DOUBLE-SSI (Age, D [Diabetes, Drainage], O [duration of Operation, vancOmycin], albUmin, B [BMI, Blood loss], cerebrospinal fluid Leakage, Early activities, Steroid use, and Segmental Instrumentation) risk score. Based on the A-DOUBLE-SSI score system, the incidence of deep SSI increased in a graded fashion from 1.06% (A-DOUBLE-SSIs score ≤8) to 40.6% (A-DOUBLE-SSIs score>15).

CONCLUSIONS

The authors developed a novel and practical model, the A-DOUBLE-SSIs risk score, that integrated easily accessible demographics, preoperative, intraoperative, and postoperative variables and could be used to predict individual risk of deep SSI in patients receiving open posterior instrumented thoracolumbar surgery.

The effect of subcutaneous fat and skin-to-lamina distance on complications and functional outcomes of minimally invasive lumbar decompression

PURPOSE

Minimally invasive lumbar decompression (MIS) in obese pzatients is technically challenging due to the use of longer tube retractors. The purpose of this study was to evaluate the impact of the thickness of the soft tissue and subcutaneous fat on complications, revisions, and patient-reported functional outcomes after MIS.

METHODS

This is a retrospective analysis of 148 consecutive patients who underwent minimally invasive lumbar decompression at our institute between 2013 and 2017 and had at least one year of follow-up. Analysis was performed five times, each time the study group was defined by another measure of adiposity: BMI > 30, skin to lamina distance at the site of surgery and at L4 > 6 cm, and subcutaneous fat thickness at the site of surgery and at L4 > 3 cm. Outcomes included intraoperative complications (durotomy or neurological deficit), possibly inadequate decompression (residual disc, reoperation), length of stay, return to the emergency room or readmission, postoperative medical complications, and functional outcomes: visual analog scores for back and leg pain, and Oswestry Disability Index (ODI).

RESULTS

Patients with a thicker layer soft tissue had a significantly higher burden of comorbidities than controls, including higher prevalence of cardiovascular disease (p = 0.002), diabetes (p < 0.001), hypertension (p < 0.001) and higher ASA scores (p = 0.002). Nevertheless, there was no significant difference between the patient groups in surgical and medical complications, functional outcomes, and other assessed outcomes.

CONCLUSION

Our results indicate that minimally invasive lumbar decompression is safe and effective for patients with a thick layer of soft tissue and subcutaneous fat.

Full-endoscopic technique mitigates obesity-related perioperative morbidity of minimally invasive lumbar decompression

PURPOSE

Obesity is associated with increased surgical complexity and postoperative complications in spine surgery. Minimally invasive procedures have been shown to lessen some of the increased risk in obese patients. This study investigated whether utilization of a working channel endoscope can further mitigate obesity-associated challenges in spinal surgery.

METHODS

A retrospective review of a single-surgeon database was conducted for all adult patients undergoing full-endoscopic unilateral laminotomies for bilateral decompression between November 2015 and March 2021. Data collected included body mass index, in operating room preparation time, procedure time, length of hospital stay, use of analgesics, complications, and quality of life measured by Oswestry Disability Index.

RESULTS

Our cohort included 174 patients. Of these, 74 (42.5%) were obese. The average age was 63.6 years. In-operating room preparation time was 70.0 ± 1.7 min for obese patients and 64.4 ± 1.5 min for non-obese patients (p = 0.02). There was no difference in operative time, durotomy rates or other perioperative complications between obese and non-obese patients. Hospital length of stay trended toward longer in the obese group, but did not reach significance. A greater percentage of obese patients were still using both narcotic and non-narcotic pain medications 2 weeks after surgery. There was no significant difference in functional outcomes between groups.

CONCLUSION

Full-endoscopic unilateral laminotomies for bilateral decompression are safe and effective in both non-obese and obese patients. The use of an endoscope can partially mitigate obesity-related morbidity in lumbar decompression. However, obesity is significantly related to increased postoperative analgesic use.

MRSA Prophylaxis in Spine Surgery Decreases Postoperative Infections

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare infection rates before and after the implementation of a quality improvement protocol focused on methicillin-resistant Staphylococcus aureus (MRSA) screening and decolonization in patients undergoing lumbar fusion and/or decompression.

SUMMARY OF BACKGROUND DATA

Prior studies have demonstrated MRSA infections comprise a sizable portion of SSIs. Additional studies are required to improve our understanding of the risks and benefits of MRSA decolonization with vancomycin prophylaxis.

METHODS

A retrospective cohort analysis was conducted on patients who underwent spinal fusion or laminectomy before (2008-2011) and after (2013-2016) the implementation of an MRSA screening and treatment protocol. Odds ratios for MRSA, methicillin-sensitive Staphylococcus aureus (MSSA), and Vancomycin-resistant Enterococcus (VRE) infection before and after screening was calculated. Multivariate analysis assessed demographic characteristics as potential independent predictors of infection.

RESULTS

A total of 8425 lumbar fusion and 2558 lumbar decompression cases met inclusion criteria resulting in a total cohort of 10,983 patients. There was a significant decrease in the overall rate of infections ( P <0.001), MRSA infections ( P <0.001), and MSSA infections ( P <0.001) after protocol implementation. Although VRE infections after protocol implementation were not significantly different ( P =0.066), VRE rates as a percentage of all postoperative infections were substantially increased (0 vs. 3.36%, P =0.007). On multivariate analysis, significant predictors of the infection included younger age (OR=0.94[0.92-0.95]), shorter length of procedure (OR=1.00[0.99-1.00]), spinal fusion (OR=18.56[8.22-53.28]), higher ASA class (OR=5.49[4.08-7.44]), male sex (OR=1.61[1.18-2.20]), and history of diabetes (OR=1.58[1.08-2.29]).

CONCLUSION

The implemented quality improvement protocol demonstrated that preoperative prophylactically treating MRSA colonized patients decreased the rate of overall infections, MSSA infections, and MRSA infections. In addition, younger age, male sex, diabetic status, greater ASA scores, and spinal fusions were risk factors for postoperative infection.

Efficacy of perioperative antibiotic prophylaxis in elective soft-tissue-only wrist arthroscopy

Wrist arthroscopy is a standard procedure in hand surgery for diagnosis and treatment of wrist injuries. Even though not generally recommended for similar procedures, general administration of perioperative antibiotic prophylaxis (PAP) is still widely used in wrist arthroscopy. A clinical ambispective dual-centre study was performed to determine whether PAP reduces postoperative infection rates after soft tissue-only wrist arthroscopies. Retrospective and prospective data was collected at two hospitals with departments specialized in hand surgery. During the study period, 464 wrist arthroscopies were performed, of these 178 soft-tissue-only interventions met the study criteria and were included. Signs of postoperative infection and possible adverse drug effects (ADEs) of PAP were monitored. Additionally, risk factors for surgical site infection (SSIs), such as diabetes mellitus and BMI, were obtained. The overall infection rate of SSI was zero. Neither in the PAP group (n = 69) nor in the control group (n = 109) were signs of postoperative infection observed. Observed symptoms of ADEs were three-times higher in the PAP group when compared to the control-group (16.3 vs 5.5%; p = 0.043). No major ADEs were observed, but one in ten patients in the PAP group reported mild to severe intestinal or hypersensitivity symptoms. We demonstrate that the number needed to treat (NNT) with PAP to prevent one postoperative infection in soft-tissue arthroscopies of the wrist is > 109. Conversely, symptoms of ADEs were reported by one out of ten patients given PAP. Considering the high NNT to prevent postoperative infection and the large number of ADEs caused by PAP, we recommend not to use PAP routinely in soft-tissue arthroscopies of the wrist. Subsequent large-scale studies should be conducted to substantiate these results.

Predictors for surgical site infection after fasciotomy in patients with acute leg compartment syndrome

BACKGROUND

Surgical site infection (SSI) is one of the most common complications of orthopedic surgery, which can result in fever, pain, and even life-threatening sepsis. This study aimed to determine the predictors of SSI after fasciotomy in patients with acute leg compartment syndrome (ALCS).

METHODS

We collected information on 125 ALCS patients who underwent fasciotomy in two hospitals between November 2013 and January 2021. Patients with SSI were considered as the SSI group and those without SSI as the non-SSI group. Univariate analysis, logistic regression analysis, and receiver operating characteristic (ROC) curve analyses were used to evaluate patient demographics, comorbidities, and admission laboratory examinations.

RESULTS

In our research, the rate of SSI (26 of 125) was 20.8%. Several predictors of SSI were found using univariate analysis, including body mass index (BMI) (p = 0.001), patients with open fractures (p = 0.003), and patients with a history of smoking (p = 0.004). Besides, the levels of neutrophil (p = 0.022), glucose (p = 0.041), globulin (p = 0.010), and total carbon dioxide were higher in the SSI group than in the non-SSI group. According to the results of the logistic regression analysis, patients with open fractures (p = 0.023, OR 3.714), patients with a history of smoking (p = 0.010, OR 4.185), and patients with a higher BMI (p = 0.014, OR 1.209) were related predictors of SSI. Furthermore, ROC curve analysis indicated 24.69 kg/m2 as the cut-off value of BMI to predict SSI.

CONCLUSIONS

Our results revealed open fractures, BMI, and smoking history as independent risk factors for SSI following fasciotomy in patients with ALCS and determined the cut-off value of BMI, enabling us to individualize the evaluation of the risk for SSI to implement early targeted treatments.

Incidence and risk factors of delayed wound healing in patients who underwent unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) has been proven as an ideal alternative surgical procedure to treat symptomatic isolated knee osteoarthritis, and recently this technique has gained its popularity. However, postoperative complications would inevitably compromise the effectiveness and patients' satisfaction. The objective of this study is to demonstrate the incidence and risk factors of delayed wound healing (DWH) after UKA. This retrospective cohort study was conducted from February 2021 to May 2022 and a total of 211 patients were enrolled. Demographic characteristics, operation-related variables, and laboratory indexes were extracted. Receiver operating characteristic analysis was performed to detect the optimum cut-off value for continuous variables. Univariate and multivariate logistic regression analysis was performed to demonstrate the risk factors of DWH. There were 155 female and 56 male patients with an average age of 64. 6 ± 6.9 years included in this study. After 6.6 ± 4.9 months' follow-up, 12 cases of DWH were observed which indicated an incidence of DWH of 5.7%, mean wound healing duration for 12 patients was 43.1 ± 19.3 days. In the univariate analysis, age > 62.5 years, postoperative hospital stay < 5.5 days, surgical incision < 10.5 cm, barbed suture, body mass index (BMI) > 32.0 kg/m2 , operation duration > 102.5 minutes, intraoperative blood loss > 102.5 mL, preoperative white blood cell count > 5.95*109 /L, preoperative seroglobulin (GLB) > 29.6 g/L, postoperative total protein < 63.4 g/L, postoperative serum albumin < 36.4 g/L, and postoperative GLB > 26.8 g/L were significantly different between patients with and without DWH (P < .05). In final multivariate logistic analysis, results showed that intraoperative blood loss > 102.5 mL (odds ratio [OR], 3.09; P = .001), postoperative hospital stay < 5.5 days (OR, 1.74; P = .014), surgical incision < 10.5 cm (OR, 1.67; P = .000), and BMI > 32.0 kg/m2 (OR, 4.47; P = .022) were independent risk factors for DWH. DWH prolongs hospital stay in UKA patients and increases healthcare expenditure; also affected the implementation schedule of postoperative functional exercise plans. Surgeons should identify patients at risk, meanwhile, make timely and correct clinical interventions to decrease the incidence of this complication.

Full-endoscopic spine surgery diminishes surgical site infections - a propensity score-matched analysis

BACKGROUND CONTEXT

Surgical site infections (SSI) are one the most frequent and costly complications following spinal surgery. The SSI rates of different surgical approaches need to be analyzed to successfully minimize SSI occurrence.

PURPOSE

The purpose of this study was to define the rate of SSIs in patients undergoing full-endoscopic spine surgery (FESS) and then to compare this rate against a propensity score-matched cohort from the National Surgical Quality Improvement Program (NSQIP) database.

DESIGN

This is a retrospective multicenter cohort study using a propensity score-matched analysis of prospectively maintained databases.

PATIENT SAMPLE

One thousand two hundred seventy-seven non-instrumented FESS cases between 2015 and 2021 were selected for analysis. In the nonendoscopic NSQIP cohort we selected data of 55,882 patients.

OUTCOME MEASURES

The occurrence of any SSI was the primary outcome. We also collected any other perioperative complications, demographic data, comorbidities, operative details, history of smoking, and chronic steroid intake.

METHODS

All FESS cases from a multi-institutional group that underwent surgery from 2015 to 2021 were identified for analysis. A cohort of cases for comparison was identified from the NSQIP database using Current Procedural Terminology of nonendoscopic cervical, thoracic, and lumbar procedures from 2015 to 2019. Trauma cases as well as arthrodesis procedures, surgeries to treat pathologies affecting more than 4 levels or spine tumors that required surgical treatment were excluded. In addition, nonelective cases, and patients with wounds worse than class 1 were also not included. Patient demographics, comorbidities, and operative details were analyzed for propensity matching.

RESULTS

In the non-propensity-matched dataset, the endoscopic cohort had a significantly higher incidence of medical comorbidities. The SSI rates for nonendoscopic and endoscopic patients were 1.2% and 0.001%, respectively, in the nonpropensity match cohort (p-value <.011). Propensity score matching yielded 5936 nonendoscopic patients with excellent matching (standard mean difference of 0.007). The SSI rate in the matched population was 1.1%, compared to 0.001% in endoscopic patients with an odds ratio 0.063 (95% confidence interval (CI) 0.009-0.461, p=.006) favoring FESS.

CONCLUSIONS

FESS compares favorably for risk reduction in SSI following spinal decompression surgeries with similar operative characteristics. As a consequence, FESS may be considered the optimal strategy for minimizing SSI morbidity.

RBC, HB, HCT, CRP, and ESR at different postoperative periods after the application of intravenous unit dose transient acid in PLIF: A case control study

Background

Tranexamic acid (TXA) has been used in posterior lumbar interbody fusion (PLIF) and reduces blood loss. However, it has not been reported whether it will continue to affect postoperative red blood cells (RBC), hemoglobin (HB), hematocrit (HCT), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The purpose of this study was to observed the above indicators at different time after PLIF with unit dose intravenous (iv) TXA.

Methods

The data of 44 patients treated by single-segment PLIF from 2020.11 to 2022.3 were retrospectively analyzed. Observation group was given a unit dose of ivTXA (1 g/100 mL) 15 min before skin incision after general anesthesia. Patients without TXA were recorded as control group. Main observation indicators include RBC, HB, HCT, CRP and ESR on the 1st, 4th, 7th and last tested day after surgery. Secondary observation indicators include postoperative activated partial thrombin time (APTT), prothrombin time (PT), thrombin time (TT), and fibrinogen (FIB); and operation time, intraoperative blood loss, postoperative drainage volume, incision healing, postoperative deep vein thrombosis and postoperative hospital stay.

Results

The operation was successfully completed without related complications. At term of main observation indicators, RBC, HB and HCT remained relatively stable, while CRP and ESR fluctuated to some extent after PLIF. The RBC, HB and HCT in the observation group were higher than those in the control group with statistically significant (p < 0.05). Except the CRP of 7th postoperative day of the observation group was significantly lower than that of the control group (p < 0.05), there was no difference in other CRP and ESR between the two groups (p > 0.05). At term of secondary observation indicators, the intraoperative blood loss and postoperative drainage volume of the observation group were lower than those of the control group with statistically significant (p < 0.05). There was no significant difference in postoperative APTT, PT, TT, FIB, and operation time and postoperative hospital stay between the two groups (p > 0.05).

Conclusion

The application of unit dose of ivTXA in PLIF can safely and effectively reduce blood loss. Meanwhile, it can also maintain higher RBC, HB, HCT levels without disturbing CRP and ESR levels after surgery.

Clinical and radiologic outcomes of biportal endoscopic lumbar discectomy in obese patients: a retrospective case-control study

BACKGROUND

Obese patients have a higher risk of complications during spinal surgery than non-obese patients. To the best of our knowledge, no studies have examined the differences in clinical and radiological outcomes after biportal endoscopic lumbar discectomy (BELD) between obese and non-obese patients. The study evaluated the association between obesity and outcomes after BELD in patients with lumbar disc herniation.

METHODS

This was a retrospective case-control study conducted from March 2017 to March 2021 at two hospitals with 360 patients who underwent BELD after showing no improvement with conservative treatment. Clinical and radiologic outcomes were retrospectively analyzed after BELD in the non-obese (body mass index [BMI] < 30 kg/m²) and obese (BMI ≥ 30 kg/m²) groups. Demographic data and surgery-related factors were compared between the two groups. Clinical outcomes were followed up for 12 months after surgery and analyzed for differences.

RESULTS

A total of 211 patients were enrolled in this study, and through case-control matching, the data of 115 patients (29, obese group; 86, non-obese group) were analyzed. The two groups showed no significant differences in Oswestry Disability Index, European Quality of Life-5 Dimensions (EQ-5D), and visual analog scale scores measured immediately after BELD and 12 months after surgery. After surgery, back pain, radiating leg pain, and EQ-5D scores improved. However, there was no significant difference in improvement, residual herniated disc, hematoma, or recurrence between the groups.

CONCLUSIONS

Obese patients who underwent BELD for lumbar disc herniation showed no significant difference in clinical and radiologic outcomes compared with non-obese patients.

Prevalence, Risk Factors and Microbiological Profile of Orthopaedic Surgical Site Infection in North-Eastern Peninsular Malaysia

Introduction

The devastating outcome of orthopaedic surgical site infections (SSI) are largely preventable if its risk factors, causative organisms and antimicrobial susceptibility patterns in the regional area are known.

Materials and methods

We conducted a retrospective study to address the lack of epidemiological and microbiological data on orthopaedic SSI in Malaysia. All the 80 patients diagnosed and treated for microbiologically proven orthopaedic SSIs in a tertiary hospital in Malaysia from April 2015 to March 2019 were included in a 1:2 case control study.

Results

The prevalence of SSI in clean and clean-contaminated surgeries was 1.243%, which is consistent with most of the studies worldwide, but is low compared to other studies done in Malaysia. The most common type of orthopaedics SSI were internal fixation infections (46.25%), superficial SSIs (25.2%) and Prosthetic joint infections (18.75%). Obesity and tobacco use were found to be significant risk factors of orthopaedic SSI. The most common perioperative prophylaxis used was IV cefuroxime. Majority of the cases (86.5%) received prolonged prophylactic antibiotics. The most common causative agent was Staphylococcus aureus (31.25%), followed by Pseudomonas aeruginosa (26.25%) and Enterobacter spp (7.5%). Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 20% of the S. aureus infections. Up to 19.4% of the Gram-negative organisms are multidrug resistant. The higher rate of isolation of organisms resistant to the prophylactic antibiotics being used may be related to the prolonged use of prophylactic antibiotics, which exerted selective pressure for the acquisition of resistant organisms.

Conclusion

Despite its relatively low prevalence in our local institution and worldwide, the prevention of SSI in orthopaedic practice is crucial to avoid morbidity, mortality and high healthcare cost. This may be achieved by control of modifiable risk factors such as obesity and tobacco use, appropriate use of prophylactic antibiotics and implementation of good surgical and infection control practices.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion

BACKGROUND

C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy.

METHODS

We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model.

RESULTS

A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age.

CONCLUSIONS

We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity.

Cefazolin prophylaxis in spine surgery: patients are frequently underdosed and at increased risk for infection

BACKGROUND CONTEXT

Perioperative antibiotics are critical in reducing the risk of postoperative spine infections. However, the efficacy and optimal weight-based prophylactic cefazolin dosing is unclear.

PURPOSE

To determine (1) if inadequate weight-based prophylactic dosing of cefazolin affects infection rates after spinal fusions, and (2) identify the optimal dosing of cefazolin.

STUDY DESIGN/SETTING

Single center retrospective cohort PATIENT SAMPLE: Patients undergoing posterior cervical or lumbar spinal fusion between January 2000 and October 2020 OUTCOME MEASURES: Postoperative surgical site infection status METHODS: Patients were grouped based on our institutionally derived dosing adequacy standards, 1 g for <60 kg, 2 g for 60 to 120 kg, and 3 g for >120 kg. Univariate comparisons and multivariate regressions identified the effect of inadequate dosing on infection rate. Patients were subsequently regrouped into cefazolin dose (grams) administered and logistic regression and receiver operating characteristic curves were compiled to determine the probability of infection based on cefazolin dose and patient weight. Alpha was set at 0.05.

RESULTS

A total of 2,643 patients met inclusion criteria and 95 infections (3.6%) were identified. The infection rate was higher in the inadequate dosing group (5.86% vs. 2.58%, p<.001). Adequate dosing was a predictor of decreased infections after lumbar fusion (OR: 0.43, p<.001), but not posterior cervical fusions (OR: 0.47, p=.065). Patients were subsequently regrouped into 1 g or 2 g of cefazolin administered resulting in a 5.01% and 2.77% infection rate, respectively (p=.005). The area under the curve (AUC) and 95% confidence interval for one (0.850 [0.777-0.924]) and two (0.575 [0.493-0.657]) g of cefazolin demonstrated lower infection rates for patients given 2 g cefazolin.

CONCLUSIONS

Patients receiving an inadequate weight-based dose of preoperative cefazolin had an increased risk of infection following spinal fusion surgery. Two grams prophylactic cefazolin significantly reduces the likelihood of infection.

Subcutaneous Fat Thickness on Erect Radiographs Is a Predictor of Infection Following Elective Posterior Lumbar Fusion

BACKGROUND

Posterior lumbar fusions are a common and successful procedure, yet surgical site infection (SSI) is still prevalent and causes significant morbidity. Obesity is a well-established risk factor for SSI. Still, the accuracy of the body mass index (BMI) caused some to suggest other metrics that are more representative of the thickness of the soft-tissue envelope in the surgical site.

METHODS

A retrospective review of all cases that developed SSI following posterior lumbar fusion over the past 5 years was done. An age and gender-matched control group was formed from the lumbar fusion cases that did not develop SSI. Demographic and clinical data were collected, and morphometric measurements of the soft-tissue envelope were performed at the level of L4 for all cases on standing x-ray imaging and magnetic resonance imaging (MRI).

RESULTS

A total of 366 patients underwent posterior lumbar fusion, 26 of whom developed SSI. BMI and skin to spinous process measurements on x-ray imaging-not MRI-were found to be significantly associated with SSI. Regression analysis further confirmed the strength of the association.

CONCLUSION

While BMI and MRI measurements are useful, wound depth measurements on x-ray imaging can be predictive of SSI in lumbar fusion cases.

CLINICAL RELEVACE

Wound depth measurements are predictive of lumbar wound infection. The information within this study can help surgeons better predict and manage infections of posterior lumbar wounds.

LEVEL OF EVIDENCE: 3

Categories

Editors-in-Chief Mark Lee and Mark Ashton propose a holistic categorisation system that is more reflective of urgency and less prone to manipulation or ‘turning off’ in times of pressure.

Increased Surgical Site Subcutaneous Fat Thickness Is Associated with Infection after Posterior Cervical Fusion

Background: Previous literature has associated increased body mass index (BMI) with risk of surgical site infection (SSI) after posterior cervical fusion (PCF) surgery. However, few studies have examined the association between local adiposity and risk of SSI, re-admission, and re-operation after PCF. Local adiposity is easily measured on pre-operative magnetic resonance imaging (MRI) and may act as a more accurate predictor compared with BMI. Patients and Methods: Subjects undergoing PCF from 2013-2018 at a single institution were identified retrospectively. Posterior cervical subcutaneous fat thickness, paraspinal muscle thickness, and lamina-to-skin distance measurements were obtained from computed tomography (CT) or MRI scans. Subjects with active infection, malignancy, or revision procedures were excluded. Results: Two hundred five patients were included with 20 developing SSIs. Subjects with SSIs had a longer fusion construct (4.90 vs. 3.71 levels; p = 0.001), higher Elixhauser comorbidity index (ECI; 2.05 vs. 1.34; p = 0.045), had a history of diabetes mellitus (30% vs. 10.8%; p = 0.026), higher subcutaneous fat thickness (30.5 vs. 23.6 mm; p = 0.013), and higher lamina-to-skin distance (66.4 vs. 57.9 mm; p = 0.027). Subcutaneous fat thickness (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.01-1.10]; p = 0.026) and lamina-to-skin distance (OR, 1.05; 95% CI, 1.01-1.09]; p = 0.014) were associated with SSI in multivariable analysis. A subcutaneous fat thickness cutoff value of 23.2 mm had 90% sensitivity and 54.1% specificity for prediction of SSI. There was no association need for re-admission or re-operation. Conclusions: Increased posterior cervical fat may increase the risk of SSI after PCF. Pre-operative advanced imaging may be a valuable tool for assisting with patient counseling, optimization, and risk stratification.

Surgical site infection following minimally invasive lobectomy: Is robotic surgery superior?

Background

Surgical site infection (SSI) in thoracic surgery remains a significant cause of morbidity and prolonged hospitalization. Minimally invasive surgery (MIS) has significantly reduced the risk of SSI. We intended to compare whether there was difference between video‐assisted thoracic surgery (VATS) and robotic‐assisted thoracic surgery (RATS) in SSI and highlight possible factors influencing SSI in lobectomy.

Methods

This retrospective study analyzed patients who underwent minimally invasive lobectomy from January 2018 to December 2019. All patients' clinical characteristics and surgery‐related information which may be related to the likelihood of SSI were recorded.

Results

A total of 1231 patients' records were reviewed with 806 VATS and 425 RATS. SSI was classified as deep or superficial SSI. Eighty‐six (7.0%) patients were found to develop an SSI with 62 patients having deep infections and 24 had superficial infection. No statistical difference in the incidence rate and category of SSI was observed between patients undergoing VATS and RATS.

Conclusions

There was no difference in the incidence of SSI between VATS and RATS lobectomy. Male gender, heavy smoking, uncontrolled diabetes mellitus, body mass index (BMI) > 27.9, more blood loss, and the higher National Healthcare Safety Network (NHSN) risk index score (1 or 2) were the independent risk factors of SSI following minimally invasive lobectomy, while male gender, uncontrolled diabetes mellitus, BMI > 27.9, more blood loss and the higher NHSN risk index score (1 or 2) were the main predictors of deep SSI.

Obesity as a Risk Factor for Postoperative Adverse Events in Skull Base Surgery

OBJECTIVE

To determine the implications of obesity on postoperative adverse events following skull base surgery.

METHODS

The 2005-2017 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for adverse events in skull base surgery cases. Patients were stratified by body mass index (BMI) into normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30) cohorts. Logistic regression was used to assess the association of overweight or obese BMI with various 30-day postoperative adverse events.

RESULTS

A total of 2305 patients were included for analysis, of which 732 (31.8%) and 935 (40.6%) were overweight or obese, respectively. The mean age was 53.8 ± 15.3 years and 1214 (52.7%) patients were female. Obese patients were younger (P = .033) and possessed higher frailty (P < .001) and ASA scores (P < .001). Operation times and lengths of hospitalization were not significantly different across patient cohorts (all P > .05). On propensity score-adjusted multivariable analysis, only bleeding (OR = 0.42, P < .001) and deep vein thrombosis (OR = 6.46, P = .015) were significantly associated with obesity. There were no significant differences in rates of readmission, reoperation, or mortality between normal weight and obese patients (all P > .05).

CONCLUSIONS

Obesity was associated with decreased postoperative bleeding and increased deep vein thromboses. Obese patients were otherwise at no higher risk for medical or surgical complications. Elevated BMI did not confer an increased risk for readmission, reoperation, or death. Thus, patient obesity should not be a major determinant in offering skull base surgery in individuals who would otherwise benefit from treatment.

The Role of Nutrition in Degenerative Cervical Myelopathy: A Systematic Review

Introduction

Degenerative cervical myelopathy (DCM) is the commonest cause of adult spinal cord impairment worldwide, encompassing chronic compression of the spinal cord, neurological disability and diminished quality of life. Evidence on the contribution of environmental factors is sparse; in particular, the role of nutrition in DCM is unknown. The objective of this review was to assess the effect of nutrition on DCM susceptibility, severity and surgical outcome.

Methods

A systematic review in MEDLINE and Embase was conducted following PRISMA guidelines. Full-text papers in English papers, focussing on cervical myelopathy and nutrition, published before January 2020 were considered eligible. Quality assessments were performed using the GRADE assessment tool. Patient demographics, nutritional factor and DCM outcomes measures were recorded. Relationships between nutritional factors, interventions and disease prognosis were assessed.

Results

In total, 5835 papers were identified of which 44 were included in the final analysis. DCM patients with pathological weight pre-operatively were more likely to see poorer improvements post-surgically. These patients experienced poorer physical and mental health improvements from surgery compared to normal weight patients and were more likely to suffer from post-operative complications such as infection, DVT, PE and hospital readmissions. Two trials reporting benefits of nutritional supplements were identified, with 1 suggesting Cerebrolysin to be significant in functional improvement. An unbalanced diet, history of alcohol abuse and malnourishment were associated with poorer post-operative outcome.

Conclusion

Although the overall strength of recommendation is low, current evidence suggests nutrition may have a significant role in optimising surgical outcome in DCM patients. Although it may have a role in onset and severity of DCM, this is a preliminary suggestion. Further work needs to be done on how nutrition is defined and measured, however, the beneficial results from studies with nutritional interventions suggest nutrition could be a treatment target in DCM.

The Effect of Morbid Obesity on Complications, Readmission, and Patient-Reported Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion: An Inverse Propensity Score Weighted Analysis

STUDY DESIGN

Retrospective review of prospectively collected data at a single institution.

OBJECTIVE

To compare perioperative and clinical outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MiTLIF).

SUMMARY OF BACKGROUND DATA

Obesity remains a serious public health concern. Obese patients who undergo lumbar fusion have historically thought to be at higher risk for complications and fare worse regarding quality-of-life outcomes. However, recent literature may demonstrate comparable risk and outcomes in obese patients. An increasing number of patients are categorized as morbidly obese (body mass index [BMI] ≥ 40 kg/m2). Perioperative and patient-reported outcomes (PROs) are lacking in this patient population.

METHODS

The authors retrospectively reviewed a prospectively collected database of all morbidly obese and non-obese patients that underwent MiTLIF between 2015 and 2018 for degenerative conditions who had minimum 1-year follow-up for outcome assessment. An inverse propensity/probability of treatment weighting was utilized to create a synthetic weighted sample in which covariates were independent of obesity designation to adjust for imbalance between groups. Generalized estimating equations (GEE) was used to estimate the association of morbid obesity and complications and 1-year PROs.

RESULTS

A total of 292 patients were analyzed with 234 non-obese patients and 58 morbidly obese patients. Multivariate analysis failed to demonstrate any association between morbid obesity and achieving minimal clinically important difference (MCID) for Oswestry disability index (ODI), visual analog scale (VAS), or short form-12 (SF-12) physical component score. However, morbid obesity was associated with significant decrease in odds of achieving MCID for SF-12 mental component score (P = 0.001). Increased surgery duration was significantly associated with morbid obesity (P = 0.001). Morbid obesity exhibited no statistically significant association with postoperative complications, readmission, pseudarthrosis, or adjacent segment disease (ASD).

CONCLUSION

Morbidly obese patients who undergo MiTLIF can achieve meaningful clinical improvement comparable to nonobese patients. Morbid obesity was associated with longer surgical times but was not associated with postoperative complications, readmission, or ASD.Level of Evidence: 3.

Preoperative PROMIS Scores Predict Postoperative Outcomes in Lumbar Spine Surgery Patients

STUDY DESIGN

Retrospective case series.

OBJECTIVE

Our objective was to examine the ability of preoperative Patient-reported Outcomes Measurement Information System (PROMIS) scores to predict postoperative achievement of a minimum clinically important difference (MCID) in outcome scores following lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

PROMIS is a computer adaptive testing system that has been validated in spine surgery patients. PROMIS allows for more efficient and personalized data collection compared to legacy assessment tools.

METHODS

A total of 138 patients who underwent lumbar spine surgery at a single institution completed PROMIS Physical Function (PF) and Pain Interference (PI) scores preoperatively and at 3, 12, and 24 months postoperatively. Univariate and multivariate analyses of PROMIS scores and clinical factors were performed. Receiver-operating characteristic curves were calculated to determine the ability of preoperative scores to predict postoperative achievement of an MCID of 8. PF and PI t score MCID achievement threshold values with 90% specificity were calculated.

RESULTS

Preoperative PROMIS PF and PI scores were significantly correlated to achievement of postoperative MCID after multivariate analysis. Patients with worse preoperative scores were more likely to achieve MCID. Preoperative PF and PI scores showed strong predictive value in determining ability to achieve postoperative MCID with respective area under the curve of 0.85 and 0.82. A preoperative PF threshold T-score of 31.6 had a 64% chance of achieving postoperative MCID, while a preoperative PI threshold t score of 67.8 had an 86% chance of achieving postoperative MCID.

CONCLUSION

Preoperative PROMIS PF and PI scores predicted improvement in postoperative PROMIS scores in lumbar spine surgery patients as worse preoperative scores correlated to improved PROMIS scores postoperatively. The calculated threshold t scores showed the ability to predict improvement in postoperative PROMIS scores. Preoperative PROMIS data may be useful in surgical decision-making and improved patient education regarding postoperative outcomes.Level of Evidence: 4.

The Influence of Body Mass Index in Obese and Morbidly Obese Patients on Complications and 30- and 90-day Readmissions Following Lumbar Spine Fusion

STUDY DESIGN

Retrospective cohort study using the 2013-2017 National Readmission Database.

OBJECTIVE

The aim of this study was to quantify the influence of body mass index (BMI) on complication and readmission rates following lumbar spine fusion.

SUMMARY OF BACKGROUND DATA

Compared to controls, patients with BMI ≥35 had greater odds of readmission, infection, and wound complications following lumbar spine fusion.

METHODS

Patients who underwent elective lumbar spine fusion within the population-based sample were considered for inclusion. Exclusion criteria included nonelective lumbar spine fusions, malnourished, anorexic, or underweight patients, and surgical indications of trauma or neoplasm. Patients were grouped by BMI: 18.5 to 29.9 (controls), 30 to 34.9 (obesity I), 35 to 39.9 (obesity II), and ≥40 (obesity III). Multivariate regression was performed to analyze differences in complications and readmissions between groups. Predictive modeling was conducted to estimate the impact of BMI on 30- and 90-day infection, wound complication, and readmissions rates.

RESULTS

A total of 86,697 patients were included for analysis, with an average age of 58.9 years and 58.9% being female. The obesity II group had significantly higher odds of infection (odds ratio [OR]: 1.82, 95% confidence interval [CI]: 1.28-2.62, P = 0.001), wound dehiscence (OR: 3.08, 95% CI: 1.70-6.18, P = 0.0006), and 30-day readmission (OR: 1.32, 95% CI: 1.11-1.58, P = 0.002), whereas the obesity III group had significantly higher odds of acute renal failure (OR: 2.14, 95% CI: 1.20-4.06, P = 0.014), infection (OR: 2.43, 95% CI: 1.72-3.48, P < 0.0001), wound dehiscence (OR: 3.76, 95% CI: 2.08-7.51, P < 0.0001), 30-day readmission (OR: 1.62, 95% CI: 1.36-1.93, P < 0.0001), and 90-day readmission (OR: 1.53, 95% CI: 1.31-1.79, P < 0.0001) compared with controls. Predictive modeling showed cumulative increases of 6.44% in infection, 3.69% in wound dehiscence, and 1.35% in readmission within 90-days for each successive BMI cohort.

CONCLUSION

Progressively higher risks for infection, wound complications, and hospital readmission were found with each progressive BMI level.Level of Evidence: 3.

Surgical Site Infection Prophylaxis and Wound Management in Spine Surgery

Surgical site infection (SSI) is a potentially devastating complication of spinal surgery that increases patient morbidity and healthcare costs. SSIs have complex and multifactorial etiologies; therefore, there are numerous opportunities for prevention and risk mitigation. The aim of this narrative review was to describe the incidence, risk factors, and outcomes of SSIs in spine surgery with an emphasis on postoperative wound care. We list and describe the preoperative, intraoperative, and postoperative evidence-based interventions that can be applied to potentially prevent SSI after spinal surgery.

Evaluation of full-endoscopic lumbar discectomy in the treatment of obese adolescents with lumbar disc herniation: a retrospective study

Background

Obese patients are at risk of complications after spinal surgery. Full-endoscopic lumbar discectomy (FELD) has advantages over conventional open surgery in the treatment of obese adult patients with lumbar disc herniation (LDH) because it can decrease perioperative complications and enhance the degree of patient satisfaction. However, no clinical studies have evaluated the efficacy of FELD in obese adolescents with LDH (ALDH). This study aimed to evaluate the efficacy of FELD for the treatment of obese ALDH.

Methods

We retrospectively collected clinical data from 208 patients with single-segment ALDH who underwent FELD in our hospital between January 2015 and December 2019. According to the WHO classification of obesity, the patients were divided into obese (BMI ≥30 kg/m²) and non-obese (BMI < 30 kg/m²) groups (control group). Based on the preoperative baseline data of the two groups, propensity score matching was performed to select patients from these groups for a comparative study. Perioperative data included operative time, intraoperative blood loss, and length of postoperative hospitalization. The visual analog scale (VAS), Oswestry disability index (ODI), and modified MacNab criteria were recorded as the main indicators of the surgical outcome. Recurrence rate and incidence of complications were recorded as minor indicators.

Results

Twenty-eight patients and 80 patients were included in the obese and non-obese groups, respectively, after 1:4 propensity score matching. Both groups showed improvements in VAS and ODI scores after surgery and at each follow-up time point (p < 0.05). However, there was no significant statistical difference in the surgical outcomes between the two groups at each follow-up time point (p > 0.05). The differences in operative time, intraoperative blood loss, and length of postoperative hospitalization were not statistically significant between the two groups (p > 0.05).

Conclusion

FELD is a safe and effective minimally invasive technique for treating obese patients with ALDH. The efficacy of FELD in obese and non-obese patients with ALDH was comparable.

Risk Factors for 30- and 90-Day Readmissions Due To Surgical Site Infection Following Posterior Lumbar Fusion

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

Identify the independent risk factors for 30- and 90-day readmission because of surgical site infection (SSI) in patients undergoing elective posterior lumbar fusion (PLF).

SUMMARY OF BACKGROUND DATA

SSI is a significant cause of morbidity in the 30- and 90-day windows after hospital discharge. There remains a gap in the literature on independent risk factors for readmission because of SSI after PLF procedures. In addition, readmission for SSI after spine surgery beyond the 30-day postoperative period has not been well studied.

METHODS

A retrospective analysis was performed on data from the 2012 to 2014 Healthcare Cost and Utilization Project Nationwide Readmissions Database. The authors identified 65,121 patients who underwent PLF. There were 191 patients (0.30%) readmitted with a diagnosis of SSI in the 30-day readmission window, and 283 (0.43%) patients readmitted with a diagnosis of SSI in the 90-day window. Baseline patient demographics and medical comorbidities were assessed. Bivariate and multivariate analyses were performed to examine the independent risk factors for readmission because of SSI.

RESULTS

In the 30-day window after discharge, this study identified patients with liver disease, uncomplicated diabetes, deficiency anemia, depression, psychosis, renal failure, obesity, and Medicaid or Medicare insurance as higher risk patients for unplanned readmission with a diagnosis of SSI. The study identified the same risk factors in the 90-day window with the addition of diabetes with chronic complications, chronic pulmonary disease, and pulmonary circulation disease.

CONCLUSIONS

Independent risk factors for readmission because of SSI included liver disease, uncomplicated diabetes, obesity, and Medicaid insurance status. These findings suggest that additional intervention in the perioperative workup for patients with these risk factors may be necessary to lower unplanned readmission because of SSI after PLF surgery.

Effect of BMI on the clinical outcome following microsurgical decompression in over-the-top technique: bi-centric study with an analysis of 744 patients

PURPOSE

Decompression is one of the most common interventions in spinal surgery. Obesity has become an increasing issue in surgical patients. Therefore, the aim of this study was to analyze the clinical outcome following lumbar microsurgical decompression in correlation with the patient's body mass index (BMI).

MATERIALS AND METHODS

A toal of 744 patients with spinal claudication that were seen at two specialized spine centers were included in this study. All patients underwent a bilateral microsurgical decompression in over-the-top technique. Patients were allocated in 4 groups based in their BMI category: 18.5-24.9 (n = 204), 25.0-29.9 (n = 318), 30.0-34.9 (n = 164) and ≥ 35 (n = 58). Clinical outcome data were recorded at baseline as well as 3, 12 and 24 months thereafter within a prospective study framework. The minimum follow-up was 12 months. For statistical analysis, data were adjusted for age, length of surgery and ASA and were analyzed by generalized linear gamma-based models.

RESULTS

Postoperative changes in all outcome parameters were clearly dependent on BMI. Patients with higher BMI were characterized by inferior baseline values for VAS Back (p < 0.05). Over the follow-up period, the groups with BMI 30-34.9 and BMI ≥ 35 benefitted significantly less from the surgery than the two slimmer groups (p < 0.05).

CONCLUSION

The data obtained from this large, homogenous cohort demonstrate that the quality of life improved substantially in all patients that were treated microsurgically for spinal stenosis. However, a BMI ≥ 30 may be considered as a negative predictor for a significantly inferior clinical outcome.

Cutibacterium acnes infections in revision surgery for persistent shoulder complaints: a retrospective cohort study

INTRODUCTION

Low-grade Cutibacterium acnes (C. acnes) infections after shoulder surgery usually result in unexplained complaints. The absence of clinical signs of infection makes the incidence unclear and underreported. This study aimed to determine the incidence of C. acnes infections in patients with artificial material and unexplained persistent shoulder complaints. We hypothesized that the incidence of C. acnes infections would be higher in patients with artificial material. Risk factors and associations between culture time and contaminations/infections were also assessed.

MATERIALS AND METHODS

This retrospective cohort study included patients with and without artificial material undergoing revision shoulder surgery for persistent complaints after primary surgery and the suspicion of a low-grade infection. Three-six cultures were taken in all patients. C. acnes infection incidence was determined and logistic regression analysis was performed to identify risk factors. The association between time to culture growth and infections/contaminations was evaluated using Kaplan-Meier analysis and log-rank test.

RESULTS

26/61 (42.6%) patients with and 14/33 (42.2%) without material had a C. acnes infection. Age (OR 0.959; 95% CI 0.914-1.000) and BMI (OR 0.884; 95% CI 0.787-0.977) were risk factors. Time to C. acnes culture positivity was not different between infections and contaminations.

CONCLUSION

The incidence of C. acnes infections was 42.6% in patients with artificial material and 42.2% in patients without artificial material. Younger age and lower BMI are risk factors. Low-grade C. acnes infections should be considered in patients with unexplained persistent complaints following shoulder surgery.

Long-term impact of obesity on patient-reported outcomes and patient satisfaction after lumbar spine surgery: an observational study

OBJECTIVE

Obese body habitus is a challenging issue to address in lumbar spine surgery. There is a lack of consensus on the long-term influence of BMI on patient-reported outcomes and satisfaction. This study aimed to examine the differences in patient-reported outcomes over the course of 12 and 24 months among BMI classifications of patients who underwent lumbar surgery.

METHODS

A search was performed using the Quality Outcomes Database (QOD) Spine Registry from 2012 to 2018 to identify patients who underwent lumbar surgery and had either a 12- or 24-month follow-up. Patients were categorized based on their BMI as normal weight (≤ 25 kg/m2), overweight (25-30 kg/m2), obese (30-40 kg/m2), and morbidly obese (> 40 kg/m2). Outcomes included the Oswestry Disability Index (ODI) and the visual analog scale (VAS) for back pain (BP) and leg pain (LP), and patient satisfaction was measured at 12 and 24 months postoperatively.

RESULTS

A total of 31,765 patients were included. At both the 12- and 24-month follow-ups, those who were obese and morbidly obese had worse ODI, VAS-BP, and VAS-LP scores (all p < 0.01) and more frequently rated their satisfaction as "I am the same or worse than before treatment" (all p < 0.01) compared with those who were normal weight. Receiver operating characteristic curve analysis revealed that the BMI cutoffs for predicting worsening disability and surgery dissatisfaction were 30.1 kg/m2 and 29.9 kg/m2 for the 12- and 24-month follow-ups, respectively.

CONCLUSIONS

Higher BMI was associated with poorer patient-reported outcomes and satisfaction at both the 12- and 24-month follow-ups. BMI of 30 kg/m2 is the cutoff for predicting worse patient outcomes after lumbar surgery.

Predictors of 2-year reoperation in Medicare patients undergoing primary thoracolumbar deformity surgery

OBJECTIVE

This was a retrospective cohort study in which the authors used a nationally representative administrative database. Their goal was to identify the risk factors for reoperation in Medicare patients undergoing primary thoracolumbar adult spinal deformity (ASD) surgery. Previous literature reports estimate that 20% of patients undergoing thoracolumbar ASD correction undergo revision surgery within 2 years. Most published data discuss risk factors for revision surgery in the general population, but these have not been explored specifically in the Medicare population.

METHODS

Using the MarketScan Medicare Supplemental database, the authors identified patients who were diagnosed with a spinal deformity and underwent ASD surgery between 2007 and 2015. The interactions of patient demographics, surgical factors, and medical factors with revision surgery were investigated during the 2 years following primary ASD surgery. The authors excluded patients without Medicare insurance and those with any prior history of trauma or tumor.

RESULTS

Included in the data set were 2564 patients enrolled in Medicare who underwent ASD surgery between 2007 and 2015. The mean age at diagnosis with spinal deformity was 71.5 years. A majority of patients (68.5%) were female. Within 2 years of follow-up, 661 (25.8%) patients underwent reoperation. Preoperative osteoporosis (OR 1.58, p < 0.0001), congestive heart failure (OR 1.35, p = 0.0161), and paraplegia (OR 2.41, p < 0.0001) independently increased odds of revision surgery. The use of intraoperative bone morphogenetic protein was protective against reoperation (OR 0.71, p = 0.0371). Among 90-day postoperative complications, a wound complication was the strongest predictor of undergoing repeat surgery (OR 2.85, p = 0.0061). The development of a pulmonary embolism also increased the odds of repeat surgery (OR 1.84, p = 0.0435).

CONCLUSIONS

Approximately one-quarter of Medicare patients with ASD who underwent surgery required an additional spinal surgery within 2 years. Baseline comorbidities such as osteoporosis, congestive heart failure, and paraplegia, as well as short-term complications such as pulmonary embolism and wound complications significantly increased the odds of repeat surgery.

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.

Infection prevention in cervical spine surgery

Surgical site infections (SSI) following cervical spine surgery can lead to significant patient morbidity and costs. Prevention of SSIs is multifactorial and can be divided in to preoperative patient optimization and intraoperative surgical factors. We performed a literature review to identify methods that can be used to prevent SSI development specifically in the cervical spine. We also present specific surgical pearls and techniques that have the potential to significantly decrease rates of cervical SSIs.

Body Mass Index and Modified Glasgow Prognostic Score Are Useful Predictors of Surgical Site Infection After Spinal Instrumentation Surgery: A Consecutive Series

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

To analyze a large consecutive cohort of patients who had undergone spinal instrumentation surgery, to characterize a patient population with surgical site infections (SSI), and to identify preoperative risk factors associated with SSI.

SUMMARY OF BACKGROUND DATA

Malnutrition is a risk factor for SSI in many health conditions; however, the evidence connecting preoperative malnutrition with SSI in spinal instrumentation surgery is limited because of the small number of retrospective studies. While the modified Glasgow prognostic score (mGPS), C-Reactive protein (CRP)-albumin ratio (CAR), controlling nutritional status index (CONUT), prognostic nutritional index (PNI), platelet-lymphocyte ratio (PLR), and neutrophil-lymphocyte ratio (NLR) are established methods for evaluating nutritious status, little has been reported on the predictive value of these indicators with respect to postoperative spinal infection.

METHODS

We retrospectively investigated 384 patients who underwent spinal instrumentation surgery. We evaluated the significance of risk factors, including mGPS, CAR, CONUT, PNI, PLR, and NLR. We then performed stepwise logistic regression analysis to analyze the concurrent effects of various factors on the prevalence of SSI.

RESULTS

Of the 384 patients analyzed, 14 were diagnosed with SSIs. Univariate analysis showed that preoperative BMI, lymphocyte count, albumin, erythrocyte sedimentation rate, CRP, CONUT, mGPS, CAR, and PNI were risk factors for SSI. Stepwise logistic regression analysis revealed that higher mGPS and lower BMI before surgery were independent risk factors for SSI. A receiver operating characteristic curve showed that the cut-off values of mGPS and BMI were 1 and 20.39, respectively.

CONCLUSION

The risk factors for SSI after spinal instrumentation surgery were mGPS more than or equal to 1 and BMI less than or equal to 20.39 kg/m. These findings could help to identify patients at higher risk of SSI after spinal instrumentation surgery.

LEVEL OF EVIDENCE

4.

Incidence of Surgical Site Infection After Spine Surgery: A Systematic Review and Meta-analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The objective of this study was to investigate the incidence of surgical site infection (SSI) in patients following spine surgery and the rate of microorganisms in these cases.

SUMMARY OF BACKGROUND DATA

Many studies have investigated the incidence and risk factors of SSI following spinal surgery, whereas no meta-analysis studies have been conducted regarding the comprehensive epidemiological incidence of SSI after spine surgery.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases for relevant studies that reported the incidence of SSI after spine surgery, and manually screened reference lists for additional studies. Relevant incidence estimates were calculated. Subgroup analysis, sensitivity analysis, and publication bias assessment were also performed.

RESULTS

Our meta-analysis included 27 studies, with 603 SSI cases in 22,475 patients. The pooled SSI incidence was 3.1%. Subgroup analysis revealed that the incidence of superficial SSI was 1.4% and the incidence of deep SSI was 1.7%. Highest incidence (13.0%) was found in patients with neuromuscular scoliosis among the different indications. The incidences of SSI in cervical, thoracic, and lumbar spine were 3.4%, 3.7%, and 2.7%, respectively. Compared with posterior approach surgery (5.0%), anterior approach showed a lower incidence (2.3%) of SSI. Instrumented surgery had a higher incidence of SSI than noninstrumented surgery (4.4% vs. 1.4%). Patients with minimally invasive surgery (1.5%) had a lower SSI incidence than open surgery (3.8%). Lower incidence of SSI was found when vancomycin powder was applied locally during the surgery (1.9%) compared with those not used (4.8%). In addition, the rates of Staphylococcus aureus, Staphylococcus epidermidis, and methicillin-resistant Staphylococci in microbiological culture results were 37.9%, 22.7%, and 23.1%, respectively.

CONCLUSION

The pooled incidence of SSI following spine surgery was 3.1%. These figures may be useful in the estimation of the probability of SSI following spine surgery.

LEVEL OF EVIDENCE

3.

Surgical Site Infection Prevention Following Spine Surgery

STUDY DESIGN

Literature review.

OBJECTIVES

Surgical site infection (SSI) following spine surgery leads to significant patient morbidity, mortality, and increased health care costs. The purpose of this article is to identify risk factors and strategies to prevent SSIs following spine surgery, with particular focus on avoiding infections in posterior cervical surgery.

METHODS

We performed a literature review and synthesis to identify methods that can be used to prevent the development of SSI following spine surgery. Specific pearls for preventing infection in posterior cervical spine surgery are also presented.

RESULTS

SSI prevention can be divided into patient and surgeon factors. Preoperative patient factors include smoking cessation, tight glycemic control, weight loss, and nutrition optimization. Surgeon factors include screening and treatment for pathologic microorganisms, skin preparation using chlorhexidine and alcohol, antimicrobial prophylaxis, hand hygiene, meticulous surgical technique, frequent irrigation, intrawound vancomycin powder, meticulous multilayered closure, and use of closed suction drains.

CONCLUSION

Prevention of SSI following spine surgery is multifactorial and begins with careful patient selection, preoperative optimization, and meticulous attention to numerous surgical factors. With careful attention to various patient and surgeon factors, it is possible to significantly reduce SSI rates following spine surgery.