An empiric analysis of 5 counter measures against surgical site infections following spine surgery-a pragmatic approach and review of the literature

A single-patient-use ECG system for cardiothoracic surgery admissions in the UK: A cost-consequence analysis

Background

Deep sternal wound infections (DSWI) are severe complications in up to 1.36% of coronary artery bypass grafting (CABG) procedures in the United Kingdom. Each event adds between £4,000 and £11,000 in healthcare costs, owing primarily to prolonged hospitalisations. ECG devices have been shown to convey infection throughout perioperative CABG. On the other hand, single-patient ECG devices (spECG) can effectively reduce the incidence of surgical site infections (SSI), including DSWI, but no assessment of spECG impact in NHS cardiac units has been conducted.

Methods

To estimate the impact of spECG on NHS cardiac units, we conducted a cost-consequence analysis modeling the CABG care pathway in the United Kingdom using Simul8 software for a probabilistic, individual-patient simulation. The simulation time was 1 year, with each patient followed from admission through 30 days post-discharge. The base case simulation mirrors the cardiac unit of Bart Health NHS Trust, London. A total of 2,183 patients are generated with demographic and clinical attributes from probabilistic distributions informed by hospital-specific inputs from NHS Digital Data. The Brompton Harefield Infection Score (BHIS) is allocated to gauge the risk of SSI. Results are averaged across 50 independent and randomly seeded iterations.

Results

Simulation results indicate a base-case savings of £388 per patient, determined by the incidence of infections rather than the number of CABG procedures. In the base-case simulation, the mean cost of care with rECG was £13,096, whereas the mean cost with spECG was £12,708, resulting in a cost saving of £388 (2021 GBP). The simulation yielded an overall 8.6% SSI incidence rECG, whereas the incidence of SSIs with spECG was 6.9%. The model was most sensitive to changes in general ward and ICU costs, and infection incidence was a stronger predictor of potential per-patient savings than annual CABG volume.

Conclusion

Single-patient ECG is a sustainable and effective alternative to reusable ECG cables and lead wires in terms of patient safety and resource allocation.

Do Preoperative Nasal Antiseptic Swabs Reduce the Rate of Surgical Site Infections After Adult Thoracolumbar Spine Surgery?

INTRODUCTION

Surgical site infection (SSI) remains a major complication after adult spinal surgery. We investigated whether adding preoperative nasal decontamination by antiseptic swab (skin and nasal antiseptic povidone-iodine, SNA-PI) to our antimicrobial protocol reduces the SSI rate among our patients undergoing thoracolumbar spinal surgery.

METHODS

We retrospectively reviewed all adult thoracolumbar spinal surgeries performed between June 2015 and May 2017 at a single hospital. Patients were divided into those who received nasal decontamination (SNA-PI+) and those who did not (SNA-PI-). SSI rates and responsible pathogens were compared between the cohorts.

RESULTS

A total of 1,555 surgeries with nasal decontamination (SNA-PI+) and 1,423 surgeries without (SNA-PI-) were included. The SSI rate in the SNA-PI+ group was 13 of 1,555 (0.8%) versus 10 of 1,423 (0.7%) for SNA-PI- group (P = 0.68). The infection rate was the highest among posterior instrumented fusions in the SNA-PI+ group (1.4%). Methicillin-sensitive Staphylococcus aureus was responsible for 70% of infections in the SNA-PI- group and 38% in the SNA-PI+ group (P = 0.13).

CONCLUSIONS

Routine nasal antiseptic swab before spine surgery did not affect the overall rate of SSI in thoracolumbar spinal surgeries. The incidence of methicillin-sensitive S aureus was lower in patients who received nasal decontamination (5/1,555, 0.3%) compared with those who did not (7/1,423, 0.5%); however, this result was not statistically significant (P = 0.57).

Wound irrigation for preventing surgical site infections

Wound irrigation (i.e. washing out a wound before wound closure) aims to reduce the microbial burden by removing tissue debris, metabolic waste, and tissue exudate from the surgical field before site closure. Although it is a popular procedure in every day surgical practice, the lack of procedure standardization, leads to studies with high heterogeneity and often controversial results. Thus, there are studies that advocate its use, while others discourage its implementation in clinical practice to reduce the risk of surgical site infection. The present article reviews the current literature on wound irrigation for preventing surgical site infections. Several irrigants are presented. Chlorexidine is generally considered to be less effective than povidone-iodine, while antibiotics are not that common nowadays, as they require prolonged exposure with the target to act. Hydrogen peroxide has several potential complications, which eliminate its use. Any differences in the incidence of surgical site infections between different irrigants, especially between antibacterial and non-bacterial ones, should be viewed sceptically. More randomized controlled studies are needed to provide better quality of evidence regarding the irrigants' effectiveness and safety.

Timing of Preoperative Surgical Antibiotic Prophylaxis After Primary One-Level to Three-Level Lumbar Fusion

OBJECTIVE

The purpose of this study was to examine the relationship between timing of preoperative surgical antibiotic prophylaxis and postoperative surgical site infections (SSIs) among patients with 1-level to 3-level lumbar fusion.

METHODS

Patients having undergone a primary 1-level to 3-level lumbar fusion at a single institution were allocated into 5 groups based on the time from preoperative antibiotic administration to incision (group A, 0-15 minutes; group B, 16-30 minutes; group C, 31-45 minutes; group D, 46-60 minutes; and group E, 61+ minutes). Timing of antibiotic administration as a continuous variable was also analyzed. All patients received irrigation with 3 L of normal saline containing bacitracin as well as local administration of vancomycin powder. SSIs were identified by the definition set forth by the 2017 Centers for Disease Control and Prevention guidelines.

RESULTS

Among 1131 patients, 27 (2.4%) were found to have an SSI. Compared with patients with antibiotic administration within 0-15 minutes before incision, patients with administration 61+ minutes before incision (group 4) had significantly higher odds of developing an SSI (P < 0.001). Patients had a 1.05-fold higher likelihood of infection for each additional minute delay of administration before incision (P < 0.001). Receiver operating characteristic analysis reported an area under the curve of 0.733 and 0.776 for time as a continuous and categorical variable, respectively. Age (P = 0.02), body mass index (P = 0.03), diabetes mellitus diagnosis (P = 0.04), and type of antibiotic (P = 0.004) were significant predictors of SSI.

CONCLUSIONS

Our results show that preoperative antibiotic administration beyond 1 hour in patients who have undergone lumbar fusion is associated with higher rates of SSI.

Sustained Postoperative Fever Without Evident Cause After Spine Instrumentation as an Indicator of Surgical Site Infection

BACKGROUND

Surgical site infection after spinal instrumentation increases morbidity and mortality as well as medical costs and is a burden to both patients and surgeons. Late-onset or sustained fever increases the suspicion for comorbid conditions. This retrospective, exploratory cohort study was conducted to identify the rate of and risk factors for sustained or late-onset postoperative fever after spinal instrumentation operations and to determine its relationship with surgical site infection.

METHODS

Five hundred and ninety-eight patients who underwent lumbar or thoracic spinal instrumentation were retrospectively reviewed. The patients were divided according to (1) whether or not they had had a sustained fever (SF[+] or SF[-]) and (2) whether or not they had had a surgical site infection (SSI[+] or SSI[-]). Clinical characteristics, surgical factors, prophylactic antibiotic usage, fever pattern, and laboratory/imaging findings were recorded for all patients by electronic medical chart review.

RESULTS

In total, 68 patients (11.4%) had a sustained fever. The rate of surgical site infection was significantly higher when the patient had sustained fever (13.2% [9 of 68] compared with 0.9% [5 of 530]; p < 0.001). Comparison of the patients who had a sustained fever but no surgical site infection (SF[+], SSI[-]) and those with both a sustained fever and surgical site infection (SF[+], SSI[+]) showed that continuous fever, an increasing or stationary pattern of inflammatory markers, and a C-reactive protein (CRP) level of >4 mg/dL on postoperative days 7 to 10 were diagnostic clues for surgical site infection. The sensitivity and specificity of postoperative magnetic resonance imaging (MRI) for the detection of surgical site infection were 40.0% and 90.9%, respectively, when MRI was performed within 1 month after surgery.

CONCLUSIONS

Although most patients with sustained fever did not have surgical site infection, fever was significantly related to surgical site infection. Continuous fever, increasing patterns of inflammatory markers, and high CRP on postoperative days 7 to 10 were diagnostic clues for surgical site infection. This study demonstrated provisional results for factors that can discriminate febrile patients with surgical site infection from febrile patients without infection. Further investigation with a larger sample size is warranted for clarification.

LEVEL OF EVIDENCE

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

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.

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.

Preoperative Maximization to Reduce Complications in Spinal Surgery

STUDY DESIGN

Invited narrative review.

OBJECTIVES

The aim of this review was to summarize current literature regarding risk factors that surgeons can optimize in the preoperative setting in the spinal surgery patient, in order to reduce complications and improve patient-reported outcomes.

METHODS

Review of the relevant literature by the authors.

RESULTS

Modifiable risk factors identified relative to the patient include obesity, malnutrition/nutrient deficiency, diabetes/hyperglycemia, preoperative anemia, vitamin D/DEXA (dual-energy radiograph absorptiometry), nicotine use/smoking, and opioid use/psychosocial factors.

CONCLUSION

By maximizing a patient's physiological and psychological status prior to elective spine surgery, we may move closer to achieving the goals of value-based care: improving patient-reported outcomes while decreasing the cost of care.

Effects of Intraoperative Intrawound Antibiotic Administration on Spinal Fusion: A Comparison of Vancomycin and Tobramycin in a Rat Model

BACKGROUND

Local, intrawound use of antibiotic powder, such as vancomycin and tobramycin, in spinal fusion surgery has become an increasingly common prophylactic measure in an attempt to reduce rates of postsurgical infection. However, the effects of localized antibiotic delivery on fusion remain unclear. The objective of this study was to examine the in vivo effects of intraoperative local delivery of 2 antibiotics commonly used in bone-grafting surgery on spinal fusion outcomes in a rat model.

METHODS

Single-level (L4-L5), bilateral posterolateral intertransverse process lumbar fusion surgery was performed on 60 female Lewis rats (6 to 8 weeks of age) using syngeneic iliac crest allograft mixed with clinical bone-graft substitute and varying concentrations of antibiotics (n = 12 each): (1) control without any antibiotics, (2) low-dose vancomycin (14.3 mg/kg), (3) high-dose vancomycin (71.5 mg/kg), (4) low-dose tobramycin (28.6 mg/kg), and (5) high-dose tobramycin (143 mg/kg). Eight weeks postoperatively, fusion was evaluated via micro-computed tomography (µCT), manual palpation, and histological analysis, with blinding to treatment group. In the µCT analysis, fusion-mass volumes were measured for each rat. Each spine specimen (L4-L5) was rated (manual palpation score) on a scale of 2 to 0 (2 = fused, 1 = partially fused, and 0 = non-fused).

RESULTS

The mean fusion-mass volume on µCT (mm) was as follows: control, 29.3 ± 6.2; low-dose vancomycin, 26.3 ± 8.9; high-dose vancomycin, 18.8 ± 7.9; low-dose tobramycin, 32.7 ± 9.0; and high-dose tobramycin, 43.8 ± 11.9 (control versus high-dose vancomycin, p < 0.05; and control versus high-dose tobramycin, p < 0.05). The mean manual palpation score for each group was as follows: control, 1.46 ± 0.58; low-dose vancomycin, 0.86 ± 0.87; high-dose vancomycin, 0.68 ± 0.62; low-dose tobramycin, 1.25 ± 0.71; and high-dose tobramycin, 1.32 ± 0.72 (control versus high-dose vancomycin, p < 0.05). The histological analyses demonstrated a similar trend with regard to spinal fusion volume.

CONCLUSIONS

Intraoperative local application of vancomycin, particularly at a supraphysiological dosage, may have detrimental effects on fusion-mass formation. No inhibitory effect of tobramycin on fusion-mass formation was observed.

CLINICAL RELEVANCE

When spine surgeons decide to use intraoperative intrawound antibiotics in spinal fusion surgery, they should weigh the reduction in surgical site infection against a possible inhibitory effect on fusion.

Persistent Postoperative Hyperglycemia as a Risk Factor for Operative Treatment of Deep Wound Infection After Spine Surgery

BACKGROUND

Surgical site infections (SSIs) affect 1% to 9% of all spine surgeries. Though previous work has found diabetes mellitus type 2 (DM2) to increase the risk for wound infection, the influence of perioperative hyperglycemia is poorly described.

OBJECTIVE

To investigate perioperative hyperglycemia as an independent risk factor for surgical site infection.

METHODS

We retrospectively identified patients undergoing operative management of SSIs occurring after spinal surgery for degenerative pathologies. These patients were individually matched to controls based upon age, surgical invasiveness, ICD-10CM, race, and sex. Cases and controls were compared regarding medical comorbidities (including diabetes), postoperative hyperglycemia, and operative time.

RESULTS

Patients in the infection group were found to have a higher BMI (33.7 vs 28.8), higher prevalence of DM2 (48.5% vs 14.7%), and longer inpatient stay (8.8 vs 4.3 d). They also had higher average (136.6 vs 119.6 mg/dL) and peak glucose levels (191.9 vs 153.1 mg/dL), as well as greater variability in glucose levels (92.1 vs 58.1 mg/dL). Multivariable logistic regression identified BMI (odds ratio [OR] = 1.13), diabetes mellitus (OR = 2.12), average glucose on the first postoperative day (OR = 1.24), peak postoperative glucose (OR = 1.31), and maximal daily glucose variation (OR = 1.32) as being significant independent predictors of postoperative surgical site infection.

CONCLUSION

Postoperative hyperglycemia and poor postoperative glucose control are independent risk factors for surgical site infection following surgery for degenerative spine disease. These data suggest that, particularly among high-risk diabetic patients, strict perioperative glucose control may decrease the risk of SSI.

Risk Factors and Prevention of Surgical Site Infections Following Spinal Procedures

STUDY DESIGN

Focused literature review.

OBJECTIVE

The objective of this article was to help identify potential risk factors as well as strategies to help prevent surgical site infections (SSIs) in spine surgery.

METHODS

An article search was performed using PubMed, EMBASE, and the Cochrane database of systematic reviews using the terms "surgery" OR "surgical" AND "spine" OR "spinal" AND "infection". Systematic review articles, meta-analyses, and clinical trials with more than 100 patients were reviewed.

RESULTS

Both patient and perioperative factors contribute to the development of SSIs. Patient factors such as smoking, obesity, diabetes, Methicillin-resistant Staphylococcus aureus (MRSA) colonization, and malnutrition are all modifiable risk factors that can lead to SSIs. Procedural steps, including preoperative MRSA screening and treatment for colonization, preoperative antibiotics, skin preparation, minimizing operative time, antibiotic or betadine irrigation, avoiding personnel turnover, and postoperative wound care have also been shown to decrease infection rates.

CONCLUSION

There are several measures a spine practitioner may be able to take in the preoperative, intraoperative, and postoperative settings. Protocols to counsel patients regarding modification of preexisting risk factors and ensure adequate antimicrobial therapy in the perioperative period may be developed to reduce SSIs in spine surgery.