Current Concepts in Perioperative Care for the Prevention of Deep Surgical Site Infections in Elective Spinal Surgery

Prophylactic postoperative measures to minimize surgical site infections in spine surgery: systematic review and evidence summary

BACKGROUND CONTEXT

There are three phases in prophylaxis of surgical site infections (SSI): preoperative, intraoperative and postoperative. There is lack of consensus and paucity of evidence with SSI prophylaxis in the postoperative period.

PURPOSE

To systematically evaluate the literature, and provide evidence-based summaries on postoperative measures for SSI prophylaxis in spine surgery.

STUDY DESIGN

Systematic review, meta-analysis, evidence synthesis.

METHODS

A systematic review conforming to PRIMSA guidelines was performed utilizing PubMed (MEDLINE), EMBASE, and the Cochrane Database from inception to January 2019. The GRADE approach was used for quality appraisal and synthesis of evidence. Six postoperative care domains with associated key questions were identified. Included studies were extracted into evidence tables, data synthesized quantitatively and qualitatively, and evidence appraised per GRADE approach.

RESULTS

Forty-one studies (nine RCT, 32 cohort studies) were included. In the setting of preincisional antimicrobial prophylaxis (AMP) administration, use of postoperative AMP for SSI reduction has not been found to reduce rate of SSI in lumbosacral spine surgery. Prolonged administration of AMP for more than 48 hours postoperatively does not seem to reduce the rate of SSI in decompression-only or lumbar spine fusion surgery. Utilization of wound drainage systems in lumbosacral spine and adolescent idiopathic scoliosis corrective surgery does not seem to alter the overall rate of SSI in spine surgery. Concomitant administration of AMP in the presence of a wound drain does not seem to reduce the overall rate of SSI, deep SSI, or superficial SSI in thoracolumbar fusion performed for degenerative and deformity spine pathologies, and in adolescent idiopathic scoliosis corrective surgery. Enhanced-recovery after surgery clinical pathways and infection-specific protocols do not seem to reduce rate of SSI in spine surgery. Insufficient evidence exists for other types of spine surgery not mentioned above, and also for non-AMP pharmacological measures, dressing type and duration, suture and staple management, and postoperative nutrition for SSI prophylaxis in spine surgery.

CONCLUSIONS

Despite the postoperative period being key in SSI prophylaxis, the literature is sparse and without consensus on optimum postoperative care for SSI prevention in spine surgery. The current best evidence is presented with its limitations. High quality studies addressing high risk cohorts such as the elderly, obese, and diabetic populations, and for traumatic and oncological indications are urgently required.

Patient-Specific Risk Adjustment Improves Comparison of Infection Rates Following Posterior Fusion for Adolescent Idiopathic Scoliosis

BACKGROUND

There is increasing interest in surgeon "performance measures." Understanding patient factors that increase the risk of adverse events is important for the comparison of such metrics among surgeons and centers. The purpose of this study was to ascertain whether patient characteristics, beyond the control of the surgeon, were associated with increased risk of postoperative infection following posterior spinal fusion for the correction of adolescent idiopathic scoliosis (AIS) and to establish a "risk-adjusted" method of reporting postoperative infection rates.

METHODS

We reviewed the data of patients from 14 participating scoliosis treatment centers who experienced an infection within 90 days following posterior spinal fusion for the treatment of AIS. Patients with a deep infection (irrigation and debridement performed) were compared with those without an infection with regard to age, sex, body mass index (BMI) percentile for age, Lenke classification of curve type, primary curve magnitude, and estimated 3-dimensional sagittal kyphosis (T5-T12). A regression model was created to identify variables that were associated with infection, and the performance of the risk model was evaluated. The actual infection rate by site was divided by the predicted infection rate for that site and multiplied by the overall rate to create a risk-adjusted rate.

RESULTS

Of 2,122 patients analyzed, 21 (1.0%) had an infection within 90 days following surgery. Obesity was the only significant risk factor (odds ratio [OR], 7.6; p ≤ 0.001), with the resultant model demonstrating good discrimination and calibration. For the 8 sites that enrolled ≥100 patients, the predicted infection rates based on the proportion of obese patients ranged from 0.8% to 1.2%. The range of the risk-adjusted infection rates varied more substantially, from 0.2% to 2.0%.

CONCLUSIONS

For the posterior approach to surgical correction of AIS, the only identified patient risk factor for postoperative infection was a BMI percentile for age of ≥95%. To assess infection rates, we suggest adjusting for the proportion of obese patients in the cohort. A risk-adjusted infection rate for posterior spinal fusion with instrumentation for AIS allows for more accurate assessment of performance and comparison among centers.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Burden of Surgical Site Infections Associated with Select Spine Operations and Involvement of Staphylococcus aureus

BACKGROUND

Spine operations may be indicated for treatment of diseases including vertebral injuries, degenerative spinal conditions, disk disease, spinal misalignments, or malformations. Surgical site infection (SSI) is a clinically important complication of spine surgery. Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), is a leading cause of post-spinal SSIs.

METHODS

PubMed and applicable infectious disease conference proceedings were searched to identify relevant published studies. Overall, 343 full-text publications were screened for epidemiologic, mortality, health care resource utilization, and cost data on SSIs associated with specified spine operations.

RESULTS

Surgical site infection rates were identified in 161 studies from North America, Europe, and Asia. Pooled average SSI and S. aureus SSI rates for spine surgery were 1.9% (median, 3.3%; range, 0.1%-22.6%) and 1.0% (median, 2.0%; range, 0.02%-10.0%). Pooled average contribution of S. aureus infections to spinal SSIs was 49.3% (median, 50.0%; range, 16.7%-100%). Pooled average proportion of S. aureus SSIs attributable to MRSA was 37.9% (median, 42.5%; range, 0%-100%). Instrumented spinal fusion had the highest pooled average SSI rate (3.8%), followed by spinal decompression (1.8%) and spinal fusion (1.6%). The SSI-related mortality rate among spine surgical patients ranged from 1.1%-2.3% (three studies). All studies comparing SSI and control cohorts reported longer hospital stays for patients with SSIs. Pooled average SSI-associated re-admission rate occurring within 30 d from discharge ranged from 20% to 100% (four studies). Pooled average SSI-related re-operation rate was 67.1% (median, 100%; range, 33.5%-100%). According to two studies reporting direct costs, spine surgical patients incur approximately double the health care costs when they develop an SSI.

CONCLUSIONS

Available published studies demonstrate a clinically important burden of SSIs related to spine operations and the substantial contribution of S. aureus (including MRSA). Preventive strategies aimed specifically at S. aureus SSIs could reduce health care costs and improve patient outcomes for spine operations.

The National Neurosurgery Quality and Outcomes Database Qualified Clinical Data Registry: 2015 measure specifications and rationale

Meaningful quality measurement and public reporting have the potential to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. Recent developments in national quality reporting programs, such as the Centers for Medicare & Medicaid Services Qualified Clinical Data Registry (QCDR) reporting option, have enhanced the ability of specialty groups to develop relevant quality measures of the care they deliver. QCDRs will complete the collection and submission of Physician Quality Reporting System (PQRS) quality measures data on behalf of individual eligible professionals. The National Neurosurgery Quality and Outcomes Database (N2QOD) offers 21 non-PQRS measures, initially focused on spine procedures, which are the first specialty-specific measures for neurosurgery. Securing QCDR status for N2QOD is a tremendously important accomplishment for our specialty. This program will ensure that data collected through our registries and used for PQRS is meaningful for neurosurgeons, related spine care practitioners, their patients, and other stakeholders. The 2015 N2QOD QCDR is further evidence of neurosurgery’s commitment to substantively advancing the health care quality paradigm. The following manuscript outlines the measures now approved for use in the 2015 N2QOD QCDR. Measure specifications (measure type and descriptions, related measures, if any, as well as relevant National Quality Strategy domain[s]) along with rationale are provided for each measure.

Irradiated allograft bone in spine surgery: to culture or not? A single center retrospective study

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

We aimed to document the rate of infection in our institution after the use of irradiated cancellous allograft or iliac crest bone autograft in vertebral fusion procedures. We also reviewed the pertinence of microbiological culture of cadaveric allograft bone prior to its implantation.

SUMMARY OF BACKGROUND DATA

Recent studies have shown similar postoperative infection rates between allograft and autograft. The pertinence of microbiological culture of allograft bone prior to its implantation is currently controversial.

METHODS

Retrospectively, we identified 338 patients who underwent spine fusion procedures for which there was a minimum of a 1-year follow-up. Files from both the neurosurgery and orthopedics divisions of the Centre hospitalier universitaire de Sherbrooke were reviewed during 1999 to 2009. Irradiated allografts were used in 164 patients and autografts were used in 174 patients. Of the 164 allografts implanted, 53 were cultured peroperatively. Postoperative spinal infection was based on documented positive spine cultures at the time of re-exploration for presumed infection. Infection rates were compared using Fisher exact test.

RESULTS

From the 53 peroperative cultures, 5 were positive (9.4%) and none of them led to antibiotherapy or surgical revision at 1 year. No significant difference was observed in the rate of surgical site infection at 1 year, after the use of irradiated allografts (1.8%) or autografts (1.7%), P = 1.0.

CONCLUSION

Perceived association with infection should not influence the surgeon in bone graft choice for spinal fusion. There is a lack of scientific evidence to recommend for or against routine cultures on allograft implantation in the literature. Our results strongly underline the pertinence of larger multicenter clinical trials to assess the pertinence of peroperative allograft bone culture.

A methodological systematic review on surgical site infections following spinal surgery: part 2: prophylactic treatments

STUDY DESIGN

A methodological systematic review.

OBJECTIVE

To critically appraise the validity of preventive effects attributed to prophylactic treatments for surgical site infection (SSI) after spinal surgery.

SUMMARY OF BACKGROUND DATA

As a result of a rapidly increasing number of spinal procedures, health care expenditure is expected to increase substantially in the foreseeable future. Administration of effective prophylactic treatments may prevent occurrence of SSIs and may thus result in lower costs. To date, however, no review appraising the methodological quality of studies evaluating prophylactic treatments for spinal SSIs has been published.

METHODS

Contemporary studies evaluating the preventive effect of prophylactic interventions on the rate of SSI after spinal surgery were searched through the Medline and EMBASE databases (January 2001 to December 2010). References were retrieved and bias-prone study features were abstracted individually and independently by 2 authors.

RESULTS

Eighteen eligible studies were identified, including 6 randomized controlled trials and 12 comparative cohort studies. Most often, antibiotic prophylaxis administration was investigated (n = 7). Included studies covered a wide variation of indications and surgical procedures. Except for 5 studies (28%), applied definitions of SSI outcomes were ambiguous. Although several important methodological aspects, including blinding of outcome assessors and attrition, were poorly reported in randomized controlled trials, these studies were far less susceptible to bias and confounding as observed in nonrandomized studies. None of the 12 cohort studies adjusted for confounding by matching, stratification, or multivariate regression techniques.

CONCLUSION

Given the plethora of previously hypothesized confounding risk factors for a spinal SSI, conduct of nonrandomized comparative therapeutic studies is strongly discouraged. On the other hand, methodological safeguards, including use of standardized definitions of putative confounders and outcomes, should be considered in more detail during the design phase of a randomized trial.