Risk Factors for Surgical Site Infections Following Adult Spine Operations

Negative pressure wound therapy in the management of postoperative spinal wound infections: a systematic review

INTRODUCTION

Postoperative wound infection after spinal surgery might be a challenge to manage. A wide range of procedures have been described for managing infected spinal wounds. An increasingly common procedure in the management of surgical site infections (SSI) is negative pressure wound therapy (NPWT), also known as vacuum-assisted closure. As there is a paucity of clear clinical advice the present investigation aims to update current evidence on the use of NPWT to manage postoperative SSI occurring after instrumented spine surgery.

METHODS

This systematic review was conducted according to the preferred reporting Items for systematic reviews and meta-analyses: the 2020 PRISMA statement. In January 2024, the following databases were accessed: PubMed, Web of Science, and Google Scholar. No time constraint was set for the search. All the clinical studies investigating the unique use of NPWT in treating postoperative spinal wound infections were accessed.

RESULTS

A total of 381 patients were included in the present study. Of them 52.5% (200 of 381 patients) were women. The mean age was 52.2 ± 15.2 years. The average length of the NPWT was 21.2 days (range 7-90 days).

CONCLUSION

NPWT could be a valuable adjuvant therapy for the management of SSI after spine surgery. Additional high-quality investigations are required to assess the efficacy and safety of NPWT in SSI after spine surgery, especially if combined with contraindications or risk factors, such as the presence of intraoperative CSF leak.

LEVEL OF EVIDENCE

Level IV, Systematic review.

Is an Elevated Preoperative CRP Level a Predictive Factor for Wound Healing Disorders following Lumbar Spine Surgery?

Postoperative wound infections are a prevalent concern among the hospital-associated infections in Europe, leading to prolonged hospital stays, increased morbidity and mortality, and substantial patient burdens. Addressing the root causes of this complication is crucial, especially given the rising number of spine surgeries due to aging populations.

METHODS

A retrospective analysis was conducted on a cohort of 3019 patients who underwent lumbar spine surgery over a decade in our department. The study aimed to assess the predictors of wound healing disorders, focusing on laboratory values, particularly inflammatory parameters.

RESULTS

Of the 3019 patients, 2.5% (N = 74) experienced deep or superficial wound healing disorders, showing the significant correlation between C-reactive protein (CRP) levels and these disorders (p = 0.004). A multivariate analysis identified several factors, including age, sex, hypertension, diabetes, cardiac comorbidity, surgical duration, dural injury, and blood loss, as being correlated with wound healing disorders.

CONCLUSION

Demographic factors, pre-existing conditions, and perioperative variables play a role in the occurrence of adverse effects related to wound healing disorders. Elevated CRP levels serve as an indicator of increased infection risk, though they are not a definitive diagnostic tool for wound healing disorders.

Association between in situ steroids and spine surgical site infections among instrumented procedures

OBJECTIVE

To estimate the association between in situ steroids and spine surgical-site infections (SSIs), assessing spinal instrumentation as an effect modifier and adjusting for confounders.

DESIGN

Case-control study.

SETTING

Rural academic medical center.

PARTICIPANTS

We identified 1,058 adults undergoing posterior fusion and laminectomy procedures as defined by the National Healthcare Safety Network without a pre-existing SSI between January 2020 and December 2021. We identified 26 SSI as cases and randomly selected 104 controls from the remaining patients without SSI.

METHODS

The primary exposure was the intraoperative administration of methylprednisolone in situ (ie, either in the wound bed or as an epidural injection). The primary outcome was a clinical diagnosis of SSI within 6 months of a patient's first spine surgery at our facility. We quantified the association between the exposure and outcome using logistic regression, using a product term to assess for effect modification by spinal instrumentation and the change-in-estimate approach to select significant confounders.

RESULTS

Adjusting for Charlson comorbidity index and malignancy, in situ steroids were significantly associated with spine SSI relative to no in situ steroids for instrumented procedures (adjusted odds ratio [aOR], 9.93; 95% confidence interval [CI], 1.54-64.0), but they were not associated with spine SSIs among noninstrumented procedures (aOR, 0.86; 95% CI, 0.15-4.93).

CONCLUSIONS

In situ steroids were significantly associated with spine SSI among instrumented procedures. The benefits of in situ steroids for pain management following spine surgery should be weighed against the risk of SSI, especially for instrumented procedures.

Analysis of risk factors for surgical site infection after colorectal surgery: a cross-sectional study in the east of China pre-COVID-19

Background

The occurrence of surgical site infection (SSI) can prolong the postoperative hospital stay, increase the economic burden of patients, and even endanger their lives. The purpose of this study was to investigate the incidence, risk factors, and microbiology of SSI after colorectal surgery (CRS) and to provide a basis for the prevention and control of SSI.

Methods

A single-center, prospective, cross-sectional study of adult patients undergoing CRS was conducted from 2010-2019. Univariate and multivariate logistic regression models were used to collect and analyze demographic information, hospital characteristics, and potential perioperative risk factors of SSI.

Results

A total of 3,302 eligible patients were included in this study, with 213 cases experiencing SSIs, resulting in an infection rate of 6.45%. Notably, the incidence of SSI decreased from 13.33% in 2010 to 3.56% in 2019 (Ptrend < 0.001). Escherichia coli accounted for the majority of isolated microorganisms (37.09%), with 49 strains exhibiting resistance to one or more antibiotics (35.25%). Multivariate analysis showed that diabetes, anastomosis leakage, wound classification (contaminated/dirty), operation duration, blood loss greater than 200 ml, and NNIS risk index score for 2 or 3 were independent risk factors. Conversely, laparoscopic approach, preoperative bowel preparation and preoperative albumin levels emerged as protective factors against SSI after CRS. Furthermore, compared to non-SSI patients, SSI patients had a significantly higher 30-day mortality rate following surgery (0.23% vs. 2.35%, p < 0.05).

Conclusion

SSI after CRS was susceptible to many factors, and the pathogen of SSI was mainly Escherichia coli. In clinical practice, measures such as correcting preoperative hypoproteinemia, choosing laparoscopic surgery, preoperative bowel preparation and shortening the duration of surgery should be taken to reduce the incidence of SSI.

Role of single or double ringed circumferential wound protectors in reducing surgical site infections following colorectal resections. A systematic review

Objective

The objective of this article is to explore whether the use of single or double ringed wound protectors (WP) in patients undergoing colorectal resection (CRR) are associated with reduced risk of surgical site infections (SSI).

Materials and methods

Analysis was conducted according to PRISMA guidelines. With the help of expert local librarians, systematic search of medical databases like MEBASE, MEDLINE and PubMed was conducted to find appropriate randomized controlled trials (RCT) according to predefined inclusion criteria. The analysis of the pooled data was done using the principles of meta-analysis on statistical software RevMan version 5.

Result

Twelve RCT on 2425 patients fulfilled the inclusion criteria. There were 1216 patients in the WP group and 1209 patients in the no-WP group. In the random effects model analysis, the use of WP during CRR was associated with the reduced risk of SSI [odds ratio 0.60, 95% CI (0.41–0.90), z = 2.49, P = 0.01]. However, there was significant heterogeneity (Tau² = 0.22; Chi² = 25.87, df = 11; (p = 0.007; I² = 57%) among included studies.

Conclusion

Use of WP seems to reduce the risk of SSI and therefore, may routinely be used during both open and laparoscopic CRR.

•

Surgical site infections (SSIs) are a frequent complication following major abdominal surgery.

•

The aim is to assess the effectiveness of using wound protectors in decreasing post operative SSIs in colorectal resection.

•

Twelve RCTs were used to obtain the submitted data.

•

Using wound protectors was associated with reduced post operative SSIs in colorectal resections.

Surgical Site Infections after Spinal Surgery in a Tropical Area: A Prospective Monocentric Observational Study

To date, no study has described the microbiological profile of surgical site infections (SSIs) after spine surgery in a tropical environment. The main objective of this study is to describe the microbiology and the risk factors of SSI after spinal surgery in a tropical climate. Our hypothesis is that the microbiology of SSIs in tropical areas is different to what is mainly described in temperate countries. As a consequence, the recommendation for antibiotic prophylaxis administered in the operative room, which mainly relays on the literature, might not be adequate in such countries. We included 323 consecutive patients who underwent a spinal intervention between 2017 and 2019, with a 2-year minimum follow-up. Objective ISO criteria were established in accordance with the criteria accepted by the Center of Disease Control in Atlanta. The identification of risk factors for SSI was carried out by uni- and multivariate analysis with a significance threshold of P < 0.05. The incidence of SSI was 7.7%. A total of 54.8% were in favor of a predominantly digestive origin of germs with an average of 1.68 bacteria found by ISO. Inadequate antibiotic prophylaxis was found in 54.8%. Age and body mass index were found to be independent risk factors for SSI. We report here an unusual microbiological profile of SSI with a predominance of gram-negative bacteria and a low proportion of Staphylococcus aureus and Staphylococcus epidermidis.

Lack of association of post-discharge prophylactic antibiotics with decreased risk of surgical site infection following spinal fusion

OBJECTIVES

To determine the prevalence and factors associated with post-discharge prophylactic antibiotic use after spinal fusion and whether use was associated with decreased risk of surgical site infection (SSI).

METHODS

Persons aged 10-64 years undergoing spinal fusion between 1 January 2010 and 30 June 2015 were identified in the MarketScan Commercial Database. Complicated patients and those coded for infection from 30 days before to 2 days after the surgical admission were excluded. Outpatient oral antibiotics were identified within 2 days of surgical discharge. SSI was defined using ICD-9-CM diagnosis codes within 90 days of surgery. Generalized linear models were used to determine factors associated with post-discharge prophylactic antibiotic use and with SSI.

RESULTS

The cohort included 156 446 fusion procedures, with post-discharge prophylactic antibiotics used in 9223 (5.9%) surgeries. SSIs occurred after 2557 (1.6%) procedures. Factors significantly associated with post-discharge prophylactic antibiotics included history of lymphoma, diabetes, 3-7 versus 1-2 vertebral levels fused, and non-infectious postoperative complications. In multivariable analysis, post-discharge prophylactic antibiotic use was not associated with SSI risk after spinal fusion (relative risk 0.98; 95% CI 0.84-1.14).

CONCLUSIONS

Post-discharge prophylactic oral antibiotics after spinal fusion were used more commonly in patients with major medical comorbidities, more complex surgeries and those with postoperative complications during the surgical admission. After adjusting for surgical complexity and infection risk factors, post-discharge prophylactic antibiotic use was not associated with decreased SSI risk. These results suggest that prolonged prophylactic antibiotic use should be avoided after spine surgery, given the lack of benefit and potential for harm.

Length of preoperative hospital stay is the dominating risk factor for surgical site infection in neurosurgery: A cohort data-driven analysis

Background

The number of days of preoperative hospital stay (PHS) is a modifiable variable that has shown contradictory surgical site infection (SSI) risk factor results in neurosurgery. We sought to pinpoint the day of PHS length related with a marked increase of risk of SSI.

Methods

From a tertiary teaching hospital, January 2015-December 2017, prospectively collected nonpercutaneous neurosurgery procedures with standard antibiotic prophylaxis and 1-year follow-up were evaluated. SSI risk factors were assessed through multiple logistic regression models with different thresholds of PHS.

Results

A total of 1012 procedures were included in the study. Incidence of SSI was 4.4%. The median PHS was higher in those with SSI than in those without (1 day, interquartile range [IQR]: 7 vs. 0 days, IQR: 1, respectively, P = 0.002). By the amount of six days of PHS, this exposure risk past the threshold of significance for impact on wound infection (OR 2.8; CI 1.23-6.39, P = 0.014). Operative time past 4 h (OR 2.11; CI 1.12-3.98; P = 0.021), and in some models, previous surgery at same admission were also identified by multivariate analysis as increasing postoperative SSI risk.

Conclusion

The gradual increase of the SSI OR associated with longer PHS days was the highest risk factor of SSI in our cohort of patients. Studies directed to reduce this complication should consider the PHS.

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.

Risk factors associated with surgical site infections after thoracic or lumbar surgery: a 6-year single centre prospective cohort study

BACKGROUND

Surgical site infection (SSI) is a risk in every operation. Infections negatively impact patient morbidity and mortality and increase financial demands. The aim of this study was to analyse SSI and its risk factors in patients after thoracic or lumbar spine surgery.

METHODS

A six-year single-centre prospective observational cohort study monitored the incidence of SSI in 274 patients who received planned thoracic or lumbar spinal surgery for degenerative disease, trauma, or tumour. They were monitored for up to 30 days postoperatively and again after 1 year. All patients received short antibiotic prophylaxis and stayed in the eight-bed neurointensive care unit (NICU) during the immediate postoperative period. Risk factors for SSI were sought using multivariate logistic regression analysis.

RESULTS

We recorded 22 incidences of SSI (8.03%; superficial 5.84%, deep 1.82%, and organ 0.36%). Comparing patients with and without SSI, there were no differences in age (p=0.374), gender (p=0.545), body mass index (p=0.878), spine diagnosis (p=0.745), number of vertebrae (p=0.786), spine localization (p=0.808), implant use (p=0.428), American Society of Anesthesiologists (ASA) Score (p=0.752), urine catheterization (p=0.423), drainage (p=0.498), corticosteroid use (p=0.409), transfusion (p=0.262), ulcer prophylaxis (p=0.409) and diabetes mellitus (p=0.811). The SSI group had longer NICU stays (p=0.043) and more non-infectious hospital wound complications (p<0.001). SSI risk factors according to our multivariate logistic regression analysis were hospital wound complications (OR 20.40, 95% CI 7.32-56.85, p<0.001) and warm season (OR 2.92, 95% CI 1.03-8.27, p=0.044).

CONCLUSIONS

Contrary to the prevailing literature, our study did not identify corticosteroids, diabetes mellitus, or transfusions as risk factors for the development of SSI. Only wound complications and warm seasons were significantly associated with SSI development according to our multivariate regression analysis.

A retrospective analysis of factors affecting surgical site infection in orthopaedic patients

Objective

To investigate the factors affecting surgical site infections (SSI) in patients undergoing orthopaedic surgery.

Methods

The electronic medical records of patients undergoing orthopaedic surgery between September 2010 and July 2018 were retrospectively retrieved and reviewed. Logistic regression analyses were used to analyse the correlation between surgery-related variables and SSI. The odds ratio (OR) and 95% confidence interval (CI) were estimated for the risk factors.

Results

Clinical data from 25 954 patients were reviewed and 804 (3.1%) were found to have become infected at the surgical site. Older age (≥60 years) was a risk factor (OR 2.218) and younger age (<18 years) was a protective factor (OR 0.258). Diabetes mellitus (OR 6.560) and hypertension (OR 3.991) were independent risk factors. Compared with type II incisions, type I incisions had a lower risk for SSI (OR 0.031), while type III incisions had a greater risk of SSI (OR 2.599). Compared with upper limbs and hands, the feet had a lower risk of infection, while surgery performed at the spine and joints did not increase the risk as compared with foot surgery.

Conclusion

Older age, hypertension, diabetes mellitus and type III incisions were risk factors for SSI following orthopaedic surgery.

Incidence and risk factors of surgical site infection following colorectal surgery in China: a national cross-sectional study

Purposes

Surgical site infection (SSI) after colorectal surgery is a frequent complication associated with the increase in morbidity, medical expenses, and mortality. To date, there is no nationwide large-scale database of SSI after colorectal surgery in China. The aim of this study was to determine the incidence of SSI after colorectal surgery in China and to further evaluate the related risk factors.

Methods

Two multicenter, prospective, cross-sectional studies covering 55 hospitals in China and enrolling adult patients undergoing colorectal surgery were conducted from May 1 to June 30 of 2018 and the same time of 2019. The demographic and perioperative characteristics were collected, and the main outcome was SSI within postoperative 30 days. Multivariable logistic regressions were conducted to predict risk factors of SSI after colorectal surgery.

Results

In total, 1046 patients were enrolled and SSI occurred in 74 patients (7.1%). In the multivariate analysis with adjustments, significant factors associated with SSI were the prior diagnosis of hypertension (OR, 1.903; 95% confidence interval [CI], 1.088–3.327, P = 0.025), national nosocomial infection surveillance risk index score of 2 or 3 (OR, 3.840; 95% CI, 1.926–7.658, P < 0.001), laparoscopic or robotic surgery (OR, 0.363; 95% CI, 0.200–0.659, P < 0.001), and adhesive incise drapes (OR, 0.400; 95% CI, 0.187–0.855, P = 0.018). In addition, SSI group had remarkably increased length of postoperative stays (median, 15.0 d versus 9.0d, P < 0.001), medical expenses (median, 74,620 yuan versus 57,827 yuan, P < 0.001), and the mortality (4.1% versus 0.3%, P = 0.006), compared with those of non-SSI group.

Conclusion

This study provides the newest data of SSI after colorectal surgery in China and finds some predictors of SSI. The data presented in our study can be a tool to develop optimal preventive measures and improve surgical quality in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05567-6.

Risk Factors for Medical and Surgical Complications After Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion

Background

The prevention of perioperative and postoperative complications is necessary to avoid poor postoperative outcomes and increased costs. Previous investigations have identified risk factors for complications after various spine procedures, but no such study exists in a population solely undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). The purpose of this study is to determine risk factors for the development of complications up to 2 years after MIS TLIF procedures.

Methods

Patients who underwent primary, single-level MIS TLIF from 2007 to 2016 were retrospectively reviewed. The incidence of medical and surgical complications up to 2 years postoperatively was determined. Patients were categorized according to demographic, comorbidity, and procedural characteristics. Bivariate Poisson regression with robust error variance was used to determine if an association existed between patient characteristics and complication incidence. A final multivariate model including all patient characteristics as controls was created using backwards, stepwise regression until only those variables with P < .05 remained.

Results

390 patients were analyzed. Upon bivariate analysis, age >50 years (P = .025), diabetes mellitus (P = .001), and operative duration >105 minutes (P = .016) were associated with increased medical complication rates. Regarding surgical complications, age ≤50 years (P < .001), obesity (P = .012), and diabetes mellitus (P = .042) were identified as risk factors on bivariate analysis. Upon final multivariate analysis, operative time >105 minutes (P = .009) and diabetes mellitus (P = .001) were independent risk factors for medical complications. Independent risk factors for surgical complications on multivariate analysis included age ≤50 years (P < .001), diabetes mellitus (P = .002), and obesity (P = .030).

Conclusions

Diabetic patients and those who underwent longer operations were at increased risk of medical complications, while younger patients, obese patients and those also with diabetes mellitus were at increased risk of surgical complications up to 2 years after MIS TLIF. Practitioners can use this information to identify patients who require preventative care before their procedure or increased postoperative vigilance and monitoring after single-level MIS TLIF.

Level of Evidence

3.

Double-blind randomized clinical trial of vancomycin in spinal arthrodesis: no effects on surgical site infection

OBJECTIVE

Surgical site infection (SSI) results in high morbidity and mortality in patients undergoing spinal fusion. Using intravenous antibiotics in anesthesia induction reduces the rate of postoperative infection, but it is not common practice to use them topically, despite recent reports that this procedure helps reduce infection. The objective of this study was to determine whether the topical use of vancomycin reduces the rate of postoperative SSI in patients undergoing thoracolumbar fusion.

METHODS

A randomized, double-blind clinical trial in a single hospital was performed comparing vancomycin and placebo in thoracolumbar fusion patients.

RESULTS

A total of 96 patients were randomized to placebo or vancomycin treatment. The mean patient age was 43 ± 14.88 years, 74% were male, and the most common etiology was fall from height (46.9%). The overall rate of postoperative SSI was 8.3%, and no difference was found between the groups: postoperative infection rates in the vancomycin and placebo groups were 8.2% and 8.5% (relative risk [RR] of SSI not using vancomycin 1.04, 95% confidence interval [CI] 0.28-3.93, p = 0.951), respectively. Patients with diabetes mellitus had higher SSI rates (RR 8.98, 95% CI 1.81-44.61, p = 0.007).

CONCLUSIONS

This is the first double-blind randomized clinical trial to evaluate the effects of topical vancomycin on postoperative infection rates in thoracolumbar fusion patients, and the results did not differ significantly from placebo.Clinical trial registration no.: RBR-57wppt (ReBEC; http://www.ensaiosclinicos.gov.br/).

Impact of health insurance status on surgical site infection incidence: A prospective cohort study

Health insurance status may affect the risk for surgical site infection (SSI). A large prospective cohort study in a Swiss tertiary-care hospital did not find evidence of a difference in SSI risk in individuals with basic versus semiprivate or private insurance in a setting with universal health insurance coverage.

Clinical Outcomes Associated With Allogeneic Red Blood Cell Transfusions in Spinal Surgery: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

The objectives of this systematic review were to report the available clinical evidence on patient outcomes associated with perioperative allogeneic red blood cell (RBC) transfusions in adult patients undergoing spinal surgery and to determine whether there is any evidence to support an association between transfusion timing and clinical outcomes.

METHODS

A systematic review of the PubMed, EMBASE, and Cochrane Library databases was performed to identify all articles examining outcomes of adult spinal surgery patients who received perioperative allogeneic RBC transfusions. The level of evidence for each study was assessed using the "Oxford Levels of Evidence 2" classification system. Meta-analysis was not performed due to the heterogeneity of reports.

RESULTS

A total of 2759 unique citations were identified and 76 studies underwent full-text review. Thirty-four studies were selected for analysis. All the studies, except one, were retrospective. Eleven studies investigated intraoperative or postoperative transfusions. Only one article compared outcomes related to intraoperative versus postoperative transfusions.

CONCLUSIONS

Perioperative transfusion is associated with increased rates of postoperative complications, especially infectious complications, and prolonged length of stay. Some evidence suggests that a dose-response relationship may exist between morbid events and the number of RBC units administered, but these findings are inconsistent. Because of the heterogeneity of reports and inconsistent findings, the incidence of specific complications remains unclear. Limited research activity has focused on intraoperative versus postoperative transfusions, or the effect of transfusion on functional outcomes of spine surgery patients. Further research is warranted to address these clinical issues.

Factors Associated with Deep Surgical Site Infection Following Spinal Surgery: A Pilot Study

Introduction

Surgical site infection (SSI) is the most common healthcare-related infection in surgical patients. Patients who have undergone spinal surgeries and have contracted postoperative SSI face increased morbidity and mortality, which invariably leads to additional burden on the healthcare system and higher costs. The risk factors for the increase in SSI in patients who have undergone spinal surgery have been investigated in numerous studies but no studies have been performed in Malaysia. The aim of this pilot study is to determine the incidence and factors associated with deep SSIs in patients that have undergone spinal surgeries.

Methods

This retrospective study includes all patients who underwent spinal surgeries at Tengku Ampuan Afzan Hospital, Kuantan, from 1 January 2016 to 31 December 2017. Patients with an active spinal infection, polytrauma, and open fractures were excluded from this study. Patient characteristics and laboratory investigations were extracted to determine the risk factors for deep SSI events. Associations between SSI and risk factors were analyzed with SPSS V21.0 (IBM, Armonk, NY).

Results

The univariate analysis indicated that fracture dislocation at the thoraco-lumbar junction (p=0.008) and a history of preoperative blood product transfusion (p=0.003) were associated with deep SSI. Other factors such as age (p=0.162), gender (p=0.262), body mass index (p=0.215), smoking status (0.272), number of vertebrae involved in the surgery (p=0.837), spinal cord involvement (p=0.259), postoperative hemoglobin reduction (p=0.816), and preoperative white blood cell count (p=0.278) were not associated with deep SSI.

Conclusions

This pilot study highlights the factors associated with deep SSI in spinal surgeries. A larger study is needed to further confirm these findings.

Does Gender Influence Postoperative Outcomes in Minimally Invasive Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

The objective of this study was to determine if an association exists between gender and postoperative improvements in patient-reported outcomes (PRO) measures following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARY OF BACKGROUND DATA

Current spine literature presents conflicting findings regarding the influence of gender on clinical outcomes.

METHODS

Patients undergoing primary, single-level MIS TLIF were retrospectively reviewed. PRO measures including Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) back and leg pain scores were collected preoperatively and 6-week, 12-week, and 6-month postoperatively. Rates of minimum clinically important difference (MCID) achievement were determined at 6-months postoperative. Statistical analysis was performed using Pearson χ analysis or Student t test.

RESULTS

In total, 169 patients, 40.83% females and 59.17% males, were included. Females experienced greater inpatient pain scores than males (POD 0: 5.30 vs. 4.69, P=0.041; POD 1: 4.80 vs. 4.13, P=0.019). Females demonstrated significantly greater ODI (43.77 vs. 36.22; P=0.002) and VAS leg (6.20 vs. 5.27; P=0.039) scores than males. No differences in postoperative improvements in ODI, VAS back or VAS leg pain scores were identified between genders, with exception to females demonstrating greater improvement in VAS leg pain at 6 months postoperatively (female: -4.40 vs. male: -3.32; P=0.033). Furthermore, no differences in MCID achievement for PROs were identified between cohorts.

CONCLUSIONS

Females demonstrated greater preoperative pain and disability as well as inpatient VAS pain scores compared to males. Furthermore, gender was not associated with differences in length of stay, perioperative complication rates, or narcotics consumption. Improvements in pain and disability, as well as rates of MCID achievement were similar between genders. These findings suggest that gender is not associated with surgical or clinical outcomes and should not be used as a predictor of outcomes following MIS TLIF.

LEVEL OF EVIDENCE

Level III.

Deep brain stimulation hardware-related infections: 10-year experience at a single institution

OBJECTIVE

Deep brain stimulation is an effective surgical treatment for managing some neurological and psychiatric disorders. Infection related to the deep brain stimulator (DBS) hardware causes significant morbidity: hardware explantation may be required; initial disease symptoms such as tremor, rigidity, and bradykinesia may recur; and the medication requirements for adequate disease management may increase. These morbidities are of particular concern given that published DBS-related infection rates have been as high as 23%. To date, however, the key risk factors for and the potential preventive measures against these infections remain largely uncharacterized. In this study, the authors endeavored to identify possible risk factors for DBS-related infection and analyze the efficacy of prophylactic intrawound vancomycin powder (VP).

METHODS

The authors performed a retrospective cohort study of patients who had undergone primary DBS implantation at a single institution in the period from December 2005 through September 2015 to identify possible risk factors for surgical site infection (SSI) and to assess the impact of perioperative (before, during, and after surgery) prophylactic antibiotics on the SSI rate. They also evaluated the effect of a change in the National Healthcare Safety Network's definition of SSI on the number of infections detected. Statistical analyses were performed using the 2-sample t-test, the Wilcoxon rank-sum test, the chi-square test, Fisher's exact test, or logistic regression, as appropriate for the variables examined.

RESULTS

Four hundred sixty-four electrodes were placed in 242 adults during 245 primary procedures over approximately 10.5 years; most patients underwent bilateral electrode implantation. Among the 245 procedures, 9 SSIs (3.7%) occurred within 90 days and 16 (6.5%) occurred within 1 year of DBS placement. Gram-positive bacteria were the most common etiological agents. Most patient- and procedure-related characteristics did not differ between those who had acquired an SSI and those who had not. The rate of SSIs among patients who had received intrawound VP was only 3.3% compared with 9.7% among those who had not received topical VP (OR 0.32, 95% CI 0.10-1.02, p = 0.04). After controlling for patient sex, the association between VP and decreased SSI risk did not reach the predetermined level of significance (adjusted OR 0.32, 95% CI 0.10-1.03, p = 0.06). The SSI rates were similar after staged and unstaged implantations.

CONCLUSIONS

While most patient-related and procedure-related factors assessed in this study were not associated with the risk for an SSI, the data did suggest that intrawound VP may help to reduce the SSI risk after DBS implantation. Furthermore, given the implications of SSI after DBS surgery and the frequency of infections occurring more than 90 days after implantation, continued follow-up for at least 1 year after such a procedure is prudent to establish the true burden of these infections and to properly treat them when they do occur.

Risk factors for surgical site infection following lumbar spinal surgery: a meta-analysis

Objective

To identify risk factors for surgical site infection (SSI) in patients who had undergone lumbar spinal surgery.

Methods

Studies published in PubMed, Web of Science, and Embase were systematically reviewed to determine risk factors for SSI following lumbar spinal surgery. Results are expressed as risk ratios (RRs) with 95% CIs and weighted mean difference (WMD) with 95% CI. A fixed-effect or random-effect model was used to pool the estimates according to heterogeneity among the studies included.

Results

Sixteen studies involving 13,393 patients were included in this meta-analysis. Pooled estimates suggested that diabetes (RR 2.19, 95% CI 1.43–3.36; P<0.001), obesity (RR 2.87, 95% CI 1.62–5.09; P<0.001), BMI (WMD 1.32 kg/m², 95% CI 0.39–2.25; P=0.006), prolonged operating time (WMD 24.96 minutes, 95% CI 14.77–35.15; P<0.001), prolonged hospital stay (WMD 2.07 days, 95% CI 0.28–3.87; P=0.024), hypertension (RR 1.28, 95% CI 1.08–1.52; P=0.005), and previous surgery (RR 2.06, 95% CI 1.39–3.06; P<0.001) were independent risk factors for SSI in patients who had undergone lumbar spine surgery. Current smoking (RR 0.89, 95% CI 0.75–1.06; P=0.178), American Society of Anesthesiologists grade >2 (RR 2.63, 95% CI 0.84–8.27; P=0.098), increased age (WMD 1.43 years, 95% CI −1.15 to 4.02; P=0.278), COPD (RR 1.21, 95% CI 0.68–2.17; P=0.521), cardiovascular disease (RR 1.63, 95% CI 0.40–6.70; P=0.495), rheumatoid arthritis (RR 1.76, 95% CI 0.53–5.90; P=0.359), and osteoporosis (RR 1.91, 95% CI 0.79–4.63; P=0.152) were not risk factors for postoperative SSI.

Conclusion

Our results identified several important factors that increased the risk of postoperative SSI. Knowing these risk factors, surgeons could adequately analyze and evaluate risk factors in patients and then develop prevention measurements to reduce the rate of SSI.

Risk Factors for Unplanned Reoperation Within 30 Days Following Elective Posterior Lumbar Spinal Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Unplanned reoperation following lumbar spinal fusion is detrimental to patients, providers, and health systems. The aim of this study was to identify risk factors associated with unplanned reoperation following elective posterior lumbar spinal fusion and assess the reasons for reoperation.

METHODS

A retrospective analysis of 22 151 patients from the American College of Surgeons National Surgical Quality Improvement Program data set between 2012 and 2015 was completed. The primary outcome measure was unplanned reoperation within 30 days. Secondary outcome measures were specific diagnoses and procedures associated with unplanned reoperation, as well as time to reoperation from initial procedure. Multiple stepwise logistic regression was employed to determine preoperative variables predictive of unplanned 30-day reoperation.

RESULTS

Patients with disseminated cancer (OR = 3.44, P = .0049), weight loss >10% in 6 months prior to surgery (OR = 3.26, P = .0276), bleeding disorders (OR = 1.92, P = .0049), American Society of Anesthesiologists score of 3 (OR = 1.46, P < .0001), body mass index of 35.0 to 39.9 (OR = 1.50, P = .0037), body mass index of ≥40 (OR = 1.83, P < .0001), and multilevel fusion (OR = 1.24, P = .0069) exhibited increased odds of 30-day reoperation. The most common diagnosis associated with reoperation was postoperative infection (n = 121, 21.1% of reoperations).

CONCLUSIONS

Predictors and causes of unplanned reoperation within 30 days following elective posterior lumbar spinal fusion are identifiable. In this study cohort, obesity, American Society of Anesthesiologists score, disseminated cancer, weight loss, bleeding disorders, and multilevel fusion were identified as significant risk factors for reoperation. Further research investigating risk factor modification on reoperation in elective posterior lumbar spinal fusion is warranted.

Prophylactic use of intraoperative vancomycin powder and postoperative infection: an analysis of microbiological patterns in 1200 consecutive surgical cases

OBJECTIVE Wound infections following spinal surgery for deformity place a high toll on patients, providers, and the health care system. The prophylactic application of intraoperative vancomycin powder has been shown to lower the infection risk after thoracolumbar decompression and fusion for deformity correction. The purpose of this study was to assess the microbiological patterns of postoperative surgical site infections (SSIs) after prophylactic use of vancomycin powder in adult patients undergoing spinal deformity surgery. METHODS All cases involving adult patients who underwent spinal deformity reconstruction at Duke University Medical Center between 2011 and 2013 with a minimum of 3 months of clinical follow-up were retrospectively reviewed. In all cases included in the study, crystalline vancomycin powder was applied to the surgical bed for infection prophylaxis. Baseline characteristics, operative details, rates of wound infection, and microbiological data for each case were gathered by direct medical record review. RESULTS A total of 1200 consecutive spine operations were performed for deformity between 2011 and 2013. Review of the associated records demonstrated 34 cases of SSI, yielding an SSI rate of 2.83%. The patients' mean age (± SD) was 62.08 ± 14.76 years. The patients' mean body mass index was 30.86 ± 7.15 kg/m², and 29.41% had a history of diabetes. The average dose of vancomycin powder was 1.41 ± 2.77 g (range 1-7 g). Subfascial drains were placed in 88% of patients. All SSIs occurred within 30 days of surgery, with deep wound infections accounting for 50%. In 74% of the SSIs cultures were positive, with about half the organisms being gram negative, such as Citrobacter freundii, Proteus mirabilis, Morganella morgani, and Pseudomonas aeruginosa. There were no adverse clinical outcomes related to the local application of vancomycin. CONCLUSIONS Our study suggests that in the setting of prophylactic vancomycin powder use, the preponderance of SSIs are caused by gram-negative organisms or are polymicrobial. Further randomized control trials of prophylactic adjunctive measures are warranted to help guide the choice of empirical antibiotic therapy while awaiting culture data.