Risk factors for surgical site infections among 1,772 patients operated on for lumbar disc herniation: a multicentre observational registry-based study

Surgical site infection following isolated lumbar discectomy increases odds of revision lumbar surgery within first 6 months, but not beyond

BACKGROUND CONTEXT

Lumbar discectomy is a commonly performed surgery following which surgical site infection (SSI) may occur. Prior literature has suggested that, following SSI related to lumbar fusion, the rate of subsequent lumbar surgeries is increased over prolonged periods of time. This has not been studied specifically for lumbar discectomy.

PURPOSE

To define factors associated with SSI following lumbar discectomy and determine if subsequently matched cohorts with and without SSI have differential rates of subsequent lumbar surgery beyond irrigation and debridement (I&Ds) over time.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Adult patients undergoing isolated primary lumbar laminotomy/discectomy were identified from the 2010-2021 M157 PearlDiver database. Exclusion criteria included: age<18 years, preoperative diagnosis of infection, neoplastic, or traumatic diagnoses within 90 days prior to index surgery, additional spinal surgeries on the same day as lumbar discectomy, and not being active in the database for at least 90 days postoperative. From this study population, those who developed SSI were identified based on undergoing I&D within 90 days after surgery. Those with versus without SSI were then matched 1:4 based on age, sex, Elixhauser Comorbidity Index (ECI), and obesity.

OUTCOME MEASURES

Following initial I&D, incidence of revision lumbar surgery (revision lumbar discectomy, lumbar laminectomy, lumbar fusion) out to 5 years after lumbar discectomy.

METHODS

Following index isolated lumbar discectomy, those with versus without SSI requiring I&D were matched and compared for incidence of secondary surgery in defined time intervals (0-6 months, 6-12 months, 1-2 years, 2-5 years) using multivariable logistic regression, controlling for patient age, sex, ECI, and obesity status.

RESULTS

Of 323,025 isolated lumbar discectomy patients, SSI requiring I&D was identified for 583 (0.18%). Multivariable analysis revealed several independent predictors of these SSIs: younger age (odds ratio [OR] 0.85 per decade increase), ECI (OR 1.22 per 2-point increase), and obesity (OR 1.30). Following matching of those with versus without SSI requiring I&D, rates of subsequent surgery beyond I&D were compared. Those with SSI had significantly increased odds of lumbar revision in the first six months (OR 5.26, p<.001), but not 6-12 months (p=.462), 1-2 years (p=.515), or 2-5 years (p=.677).

CONCLUSIONS

Overall, SSI requiring I&D is a rare postoperative complication following lumbar discectomy. If occurring, subsequent surgery beyond I&D was higher in the first 6 months, but then not increased at subsequent time points out to five years.

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

STUDY DESIGN

A meta-analysis.

BACKGROUND

We performed a meta-analysis to explore risk factors of surgical site infection (SSI) following spinal surgery.

METHODS

An extensive search of literature was performed in English database of PubMed, Embase, and Cochrane Library and Chinese database of CNKI and WANFANG (up to October 2020). We collected factors including demographic data and surgical factor. Data analysis was conducted with RevMan 5.3 and STATA 12.0.

RESULTS

Totally, 26 studies were included in the final analysis. In our study, the rate of SSI after spinal surgery was 2.9% (1222 of 41,624). Our data also showed that fusion approach (anterior vs posterior; anterior vs combined), osteotomy, transfusion, a history of diabetes and surgery, hypertension, surgical location (cervical vs thoracic; lumbar vs thoracic), osteoporosis and the number of fusion levels were associated with SSI after spinal surgery. However, age, sex, a history of smoking, body mass index, fusion approach (posterior vs combined), surgical location (cervical vs lumbar), duration of surgery, blood loss, using steroid, dural tear and albumin were not associated with development of SSI.

CONCLUSIONS

In our study, many factors were associated with increased risk of SSI after spinal surgery. We hope this article can provide a reference for spinal surgeons to prevent SSI after spinal surgery.

Predictive Factors for Successful Treatment of Deep Incisional Surgical Site Infections following Instrumented Spinal Surgeries: Retrospective Review of 1832 Cases

Background: Surgical site infection (SSI) is a major complication in spinal instrumentation that is often difficult to treat. The purpose of this study was to identify and determine prognostic indicators for successful treatment of spine instrumentation SSI. Methods: Retrospectively, spine surgery cases were examined on SSI diagnosis. Post-instrumentation SSI patients were categorized as “Successful” if SSI subsided after single debridement. Patients in whom SSI did not subsided and/or required removal of instrumentation were classified as “Challenging”. We investigated the relation of treatment outcomes to patients and treatment factors. Results: A total of 1832 spinal instrumentation cases were recognized with 44 (2.40%) SSI cases. White blood cell count, C-reactive protein (CRP) levels, causative bacteria (i.e., S. Aureus or MRSA), trauma injury, and early-stage antimicrobial agent sensitivity correlated with treatment prognosis. Multivariate analysis highlighted CRP levels and applying early-stage sensitive antibiotics as potential impactful predictive factors for successful treatment. Conclusions: Our results demonstrated that early selection of sensitive antimicrobial agents is critical and emphasizes the potential for early-stage classification methods such as Gram staining. Additionally, S. Aureus and MRSA SSI formed significantly more challenging infections to treat, thus requiring consideration when deciding on instrumentation retention. These factors offer promising aspects for further large-scale studies.

Symptomatic Epidural Hematoma after Elective Posterior Lumbar Decompression: Incidence, Timing, Risk Factors, and Associated Complications

BACKGROUND

Symptomatic post-operative lumbar epidural hematoma (PLEH) is a complication of lumbar spine surgery that can cause permanent neurologic consequences through compression of the cauda equina and nerve roots.

QUESTIONS/PURPOSES

We sought to investigate the incidence, timing, and risk factors for symptomatic epidural hematomas following posterior lumbar decompression, as well as to identify additional post-operative complications associated with symptomatic lumbar epidural hematomas.

METHODS

Elective lumbar spine procedures were identified in the National Surgical Quality Improvement Program (NSQIP) database between 2012 and 2016. Analyzed predictors of reoperation or readmission within 30 days for symptomatic PLEH included demographics, comorbidities, pre-operative laboratory values, peri-operative characteristics, and post-operative complications.

RESULTS

There were 75,878 cases included in the analysis. The incidence rate of symptomatic PLEH was 0.27% (n = 206), 54.4% (n = 112) of which occurred within 5 days of the procedure. Increased age, obesity (body mass index of 35 or higher), peri-operative transfusion, multilevel surgery (two or more levels), dural tear repair, and microscope use were independently associated with PLEH. Post-operative complications associated with PLEH included surgical site infection and urinary tract infection.

CONCLUSIONS

Readmission or reoperation for symptomatic PLEH following elective lumbar spine surgery is rare and can occur many days or weeks after a procedure. There are modifiable risk factors for PLEH and associated additional post-operative complications that physicians should be suspicious of following posterior lumbar decompression.

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.

Intraspinal Delivery of Schwann Cells for Spinal Cord Injury

Cell transplant-mediated tissue repair of the damaged spinal cord is being tested in several clinical trials. The current candidates are neural stem cells, stromal cells, and autologous Schwann cells (aSC). Due to their peripheral origin and limited penetration of astrocytic regions, aSC are transplanted intralesionally as compared to neural stem cells that are transplanted into intact spinal cord. Injections into either location can cause iatrogenic injury, and thus technical precision is important in the therapeutic risk-benefit equation. In this chapter, we discuss how we bridged from transplant studies in large animals to human application for two Phase 1 aSC transplant studies, one subacute and one chronic. Preclinical SC transplant studies conducted at the University of Miami in 2009-2012 in rodents, minipigs, and primates supported a successful Investigational New Drug (IND) submission for a Phase 1 trial in subacute complete spinal cord injury (SCI). Our studies optimized the safety and efficiency of intralesional cell delivery for subacute human SCI and led to the development of new simpler techniques for cell delivery into subjects with chronic SCI. Key parameters of delivery methodology include precision localization of the injury site, stereotaxic devices to control needle trajectory, method of entry into the spinal cord, spinal cord motion reduction, the volume and density of the cell suspension, rate of delivery, and control of shear stresses on cells.

Lumbar Disc Herniation

PURPOSE OF REVIEW

Substantial advancements have been made in the cause, diagnosis, imaging, and treatment options available for patients with lumbar disc herniation (LDH). We examined the current evidence and highlight the concepts on the frontline of discovery in LDH.

RECENT FINDINGS

There are a myriad of novel etiologies of LDH detailed in recent literature including inflammatory factors and infectious microbes. In the clinical setting, recent data focuses on improvements in computer tomography as a diagnostic tool and non-traditional injection options including tumor necrosis alpha inhibitors and platelet-rich plasma. Operative treatment outcomes have focused on minimally invasive endoscopic approaches and demonstrated robust 5-year post-operative outcomes. Advances in the molecular etiology of LDH will continue to drive novel treatment options. The role of endoscopic treatment for LDH will continue to evolve. Further research into10-year outcomes will be necessary as this surgical approach continues to gain widespread popularity.