Surgical Site Infections in Spine Surgery: Preoperative Prevention Strategies to Minimize Risk

Efficacy of prophylactic use of intraoperative vancomycin powder in preventing surgical site infection in neurological surgeries in Irrua, Nigeria: A randomized controlled study

PURPOSE

The objective was to determine the efficacy of intraoperative vancomycin powder in preventing SSIs in neurological surgeries.

METHODS

A prospective randomized controlled study of patients who had clean cranial and non-implant spine surgeries at the Irrua Specialist Teaching Hospital, Irrua, Nigeria from February 1, 2021 to January 31, 2022. Patients were randomized into two groups. Group A patients had prophylactic intraoperative vancomycin powder applied to the surgical bed before wound closure while group B patients did not. Patients in both groups were followed up for 30 days post-operatively for evidence of SSI. The occurrence of SSIs was determined using clinical and laboratory parameters. Baseline characteristics, operative details, rates of wound infection, and microbiological data for each case were recorded. Data was analyzed using Statistical Package for Scientific Solution (SPSS) version 23 software.

RESULTS

Forty-two patients were randomized into 2 groups of 21 patients each. The age range of the patients was 20 to 80 years. The majority of the patients were males (32 out of 42). The mean age of patients in group A was 48.05 ± 17.03 years, while group B had a mean age of 45.95 ± 19.14 years. The mean Body Mass Index of patients in groups A and B were 23.92 ± 5.21 and 23.21 ± 3.99 respectively. Seven out of 21 patients (33.3 %) in the control group ( group B) had superficial SSIs while no patient in the experimental group had SSI, p-value < 0.05. The organisms cultured were Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus.

CONCLUSION

Intraoperative vancomycin powder was effective in reducing the rate of SSIs following neurological surgeries and without adverse drug reactions.

Effect of drain placement in short-level spinal surgery on postoperative wound infection: A meta-analysis

In the meta-analysis, we evaluated the efficacy of placing drainage channels following single- or double-level spine surgery in order to decrease the incidence of postoperative injury. We conducted the analysis with the help of four databases: PubMed, Embase, Cochrane Library and Web of Science. A review of related studies was carried out after evaluating the quality of the literature against the classification and exclusion criteria set for the trial. Calculation of 95% CI, OR and MD was performed with fixed-effect models. A meta-analysis of the data was carried out with RevMan 5.3. Meta-analyses of randomized controlled trial (RCT) did not indicate that there were a statistically significantly different incidence of postoperative wound infections among those who received drainage compared to those who did not receive drainage (OR, 2.29; 95% CI, 0.50, 10.41 p = 0.28). Moreover, there were no statistically significant differences in post-operation hematoma (OR, 1.20; 95% CI, 0.27, 5.28 p = 0.81) and visual analogue scale score (MD, -0.01; 95% CI, -1.34, 1.33 p = 0.99). Thus, placing drainage in short-levels of spine operation did not significantly influence the outcome of postoperative wound complications. Nevertheless, because of the limited sample size chosen for this meta-analysis, caution should be exercised when treating these data. More high-quality RCT trials with a large number of samples are required to confirm the findings.

Evaluating compliance with the 2013 best practice guidelines for preventing surgical site infection in high-risk pediatric spine surgery

PURPOSE

Best Practice Guidelines (BPGs) were published one decade ago to decrease surgical site infection (SSI) in pediatric spinal deformity. Successful implementation has not been established. This study evaluated surgeon compliance with items on the BPG. We hypothesized that BPG authors and surgeons with more experience, higher caseload, and awareness of the BPG would have higher compliance.

METHODS

We queried North American and European surgeons, authors and non-authors, and members of various spine study groups on adherence to BPGs using an anonymous survey. Mean compliance scores (MCSs) were developed by correlating Likert responses with MCSs ("None of the time" = no compliance = MCS 0, "Sometimes" = weak to moderate = MCS 1, "Most of the time" = high = MCS 2, "All the time" = perfect = MCS 3).

RESULTS

Of the 142 respondents, 73.7% reported high or perfect compliance. Average compliance scores for all guidelines was 2.2 ± 0.4. There were significantly different compliance scores between North American and European surgeons (2.3 vs 1.8, p < 0.001), authors and non-authors (2.5 vs. 2.2, p = 0.023), and surgeons with and without knowledge of the BPGs (2.3 vs. 1.8, p < 0.001). There was a weak correlation between BPG awareness and compliance (r = 0.34, p < 0.001) and no correlation between years in practice (r = 0.0, p = 0.37) or yearly caseload (r = 0.2, p = 0.78) with compliance.

CONCLUSIONS

Compliance among our cohort of surgeons surveyed was high. North American surgeons, authors of the BPGs and those aware of the guidelines had increased compliance. Participation in a spine study group, years in practice, and yearly caseload were not associated with compliance.

LEVEL OF EVIDENCE

Level V-expert opinion.

Development of multidisciplinary, evidenced-based protocol recommendations and implementation strategies for anterior lumbar interbody fusion surgery following a literature review

The anterior lumbar interbody fusion (ALIF) procedure involves several surgical specialties, including general, vascular, and spinal surgery due to its unique approach and anatomy involved. It also carries its own set of complications that differentiate it from posterior lumbar fusion surgeries. The demonstrated benefits of treatment guidelines, such as Enhanced Recovery after Surgery in other surgical procedures, and the lack of current recommendations regarding the anterior approach, underscores the need to develop protocols that specifically address the complexities of ALIF. We aimed to create an evidence-based protocol for pre-, intra-, and postoperative care of ALIF patients and implementation strategies for our health system. A 12-member multidisciplinary workgroup convened to develop an evidence-based treatment protocol for ALIF using a Delphi consensus methodology and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system for rating the quality of evidence and strength of protocol recommendations. The quality of evidence, strength of the recommendation and specific implementation strategies for Methodist Health System for each recommendation were described. The literature search resulted in 295 articles that were included in the development of protocol recommendations. No disagreements remained once the authors reviewed the final GRADE assessment of the quality of evidence and strength of the recommendations. Ultimately, there were 39 protocol recommendations, with 16 appropriate preoperative protocol recommendations (out of 17 proposed), 9 appropriate intraoperative recommendations, and 14 appropriate postoperative recommendations. This novel set of evidence-based recommendations is designed to optimize the patient's ALIF experience from the preoperative to the postoperative period.

Effects of Preoperative Use of Povidone-Iodine-Impregnated Dressing on Postoperative Rate of Surgical Site Infection in Patients Undergoing Posterolateral Lumbar Spinal Fusion Surgery: A Randomized, Nonblinded, Active-Controlled Trial

BACKGROUND AND OBJECTIVES

No study has evaluated the efficacy of using preoperative antiseptic dressings in reducing the rate of surgical site infection (SSI) in spine surgery thus far. To investigate the efficacy of the use of preoperative povidone-iodine-impregnated antiseptic dressings in patients undergoing instrumented posterolateral lumbar spinal fusion.

METHODS

This was a randomized, nonblinded, active-controlled, parallel-group clinical trial. Patients were randomly assigned to the 2 study groups, including treatment and control. Patients in the treatment group received povidone-iodine-impregnated antiseptic dressing applied to the anticipated incision site 12 hours before the operation. The control group merely received the standard perioperative care with no additional intervention or placebo. Patients were followed up for 90 days, and SSIs were recorded.

RESULTS

A total of 200 patients were included in this study (100 in each arm). Three cases of SSI were observed in the treatment group compared with 12 in the control one. A significant reduction in the postoperative rate of SSI was observed in the treatment group compared with the control one (P = .029). In addition to study intervention (P = .029), body mass index (P = .005), smoking status (P = .005), duration of the procedure (P = .003), American Society of Anesthesiologists class (P = .002), and diabetes mellitus (P < .001) were significantly associated with the postoperative rate of SSI.

CONCLUSION

To the best of our knowledge, this study for the first time showed that preoperative use of antiseptic dressings is significantly effective in reducing the rate of SSI in instrumented posterior lumbar spinal fusion surgery. Future studies are warranted to evaluate the efficacy of different preparations or the effectiveness of the present one in patients undergoing spine procedures with other surgical characteristics.

Perioperative Urinary Catheter Use and Association to (Gram-Negative) Surgical Site Infection after Spine Surgery

This study evaluates potential associations between the perioperative urinary catheter (UC) carriage and (Gram-negative) surgical site infections (SSIs) after spine surgery. It is a retrospective, single-center, case-control study stratifying group comparisons, case-mix adjustments using multivariate logistic regression analyses. Around half of the patients (2734/5485 surgeries) carried a UC for 1 day (median duration) (interquartile range, 1-1 days). Patients with perioperative UC carriage were compared to those without regarding SSI, in general, and Gram-negative, exclusively. The SSI rate was 1.2% (67/5485), yielding 67 revision surgeries. Gram-negative pathogens caused 16 SSIs. Seven Gram-negative episodes revealed the same pathogen concomitantly in the urine and the spine. In the multivariate analysis, the UC carriage duration was associated with SSI (OR 1.1, 95% confidence interval 1.1-1.1), albeit less than classical risk factors like diabetes (OR 2.2, 95%CI 1.1-4.2), smoking (OR 2.4, 95%CI 1.4-4.3), or higher ASA-Scores (OR 2.3, 95%CI 1.4-3.6). In the second multivariate analysis targeting Gram-negative SSIs, the female sex (OR 3.8, 95%CI 1.4-10.6) and a UC carriage > 1 day (OR 5.5, 95%CI 1.5-20.3) were associated with Gram-negative SSIs. Gram-negative SSIs after spine surgery seem associated with perioperative UC carriage, especially in women. Other SSI risk factors are diabetes, smoking, and higher ASA scores.

Effectiveness of Toothbrushing Technique for Biofilm Removal and Postoperative Infection Control after Spinal Fusion Surgery: A Retrospective Study

This retrospective study was designed to investigate the effectiveness of using a toothbrush, which is commonly used in our daily life, for biofilm removal and infection control in the treatment of spinal infections occurring after spinal fusion surgery. Currently, a biofilm is thought to form on the surface of the metal inserted during spine fusion surgery. We aim to determine the differences in clinical outcomes between using and not using a toothbrush to remove biofilm while performing conventional drainage, curettage, and debridement. A total of 1081 patients who underwent anterior or posterior spinal fusion surgery between November 2018 and October 2022 were screened. The study included 60 patients who developed surgical site infection and underwent incision and drainage surgery either with a toothbrush (n = 20) or without a toothbrush (n = 40). Failure of infection control that requires revision surgery occurred in 2 patients (10%) in the Toothbrush group and in 14 patients (35%) in the No-Toothbrush group (p = 0.039). Thus, the rate of additional surgery was significantly lower in the Toothbrush group. Additionally, normalization of c-reactive protein levels occurred significantly faster in the Toothbrush group (p = 0.044). Therefore, using a toothbrush to treat spinal infections following spinal fusion surgery appears to have beneficial mechanical debridement effects, resulting in improved clinical results, which were also confirmed based on the electron microscopic images.

A microbiology study on the wounds of pediatric patients undergoing spinal fusion for scoliosis

PURPOSE

Surgical site infection is a significant complication in posterior spinal fusion for scoliosis in pediatric and adolescent patients. Current literature demonstrates a lack of consensus regarding best prophylactic systemic and topical antibiotic regimens for reducing infection rates. This study aims to identify which common microbes are present at particular locations in the spine, and whether these are covered by our current systemic and topical antibiotic prophylaxis regimens.

METHODS

A prospective observational study at a National Children's Hospital was conducted on 21 consecutive patients who underwent elective surgery for spinal deformity. Swabs were taken from four layers of the spine, including the superficial skin surface at the start of the case (after surgical site preparation with povidone-iodine), the deep dermis, and the deep surgical bed at the end of exposure and again after the corrective maneuver prior to closure. At each layer, swabs were taken from the proximal, middle, and distal portion of the wound. Swabs were sent to the laboratory for culture and susceptibility testing.

RESULTS

Thirteen (62%) of patients had positive microbial growth. Two microbes were identified, Staphylococcus epidermidis (9.5% of patients) and Cutibacterium acnes (Propionibacterium acnes) (52% of patients). 100% of these microbes were sensitive to cefazolin and vancomycin. 3% of patients had positive growth at the skin layer, 32% positive at the dermal layer, 17% positive after exposure, and 40% positive at the conclusion of the case (p = 0.006). No difference was observed in microbial presence in the upper thoracic, lower thoracic and lumbar spine.

CONCLUSION

Despite adequate surgical site preparation and sterile procedure, microbial contamination remains abundant in the dermal layer and deeper in the spinal wound throughout the case.

Investigating the Association of Patient Body Mass Index With Posterior Subcutaneous Fat Thickness in the Cervical Spine: A Retrospective Radiographic Study

INTRODUCTION

Although BMI is often used as a surrogate for posterior cervical subcutaneous fat thickness (SFT), the association of BMI with cervical SFT is unknown. We performed a retrospective radiographic study to analyze the relationship between BMI and cervical SFT.

METHODS

This was a retrospective cohort study of patients with cervical CT scans. SFT was assessed by measuring the distance (mm) from the spinous processes of C2-C7 to the skin edge. Pearson correlations and linear regression were used to analyze the relationship between BMI and SFT. One-way ANOVA was used to analyze differences in C2-C7 distances while stratifying by BMI.

RESULTS

A total of 96 patients were included. BMI had a moderate correlation with average C2-C7 (r=0.546, p < 0.05) SFT, and a weak to moderate correlation with each individual C2-C7 distance. The strongest correlation was at the C7 level (r= 0.583, p < 0.05). These analyses remained significant controlling for potential confounders of patient age, sex, and diabetes. No difference was found in the average C2-C7 distance in patients with BMIs of 25-30 compared to those with BMIs of 30-40 (p=0.996), whereas in patients with BMI <25 and BMI >40, differences were significant (p < 0.05).

CONCLUSIONS

BMI is not strongly correlated with SFT in the cervical spine. Although BMI less than 25 or greater than 40 is correlated with respectively decreased or increased cervical SFT, BMI of 25-40 is not correlated with cervical SFT. This is clinically important information for surgeons counseling patients on perioperative risk before undergoing cervical spine procedures, namely infection. Further research delineating the relationship between posterior SFT and surgical site infection in the cervical spine is warranted.

Endowing biodegradable Zinc implants with dual-function of antibacterial ability and osteogenic activity by micro-addition of Mg and Ag (≤ 0.1 wt.%)

Infection remains the devastating complications associated with surgical fixation of bones fractured during trauma. In this study, we report a low-alloyed Zn-Mg-Ag that simultaneously has optimized strength degeneration profiles during degradation, outstanding antibacterial efficacy and osteogenic activity. Our results showed that Zn-0.05Mg-0.1Ag alloy had favorable mechanical properties (UTS: 247.8 ± 1.6 MPa, Elong.: 35 ± 2.2 %) and presented a better hold of mechanical integrity than pure Zn during 28 days corrosion, 2.6 % vs. 18.7 % reduction. After one-year of natural aging, the alloy still preserved an elongation of 24.07 ± 3.84 %. As verified by microbial cultures, Zn-0.05Mg-0.1Ag alloy demonstrated high antibacterial performance against Gram-positive and Gram-negative strains, as well as antibiotic-resistant strains (MRSA) in vitro and in vivo due to the synergistic antibacterial actions of Zn²⁺ and Ag⁺. Meanwhile, Zn-Mg-Ag alloy also exhibited enhanced viability, osteogenic differentiation, and gene expressions of osteoblasts in vitro, as well as promoted osteogenic activity than pure Zn in the femoral condyle defect repair model. The co-releasing of Zn, Mg and Ag ions did not induce toxic side effects. Collectively, low alloyed Zn-0.05Mg-0.1Ag indicated long-lasting mechanical integrity during degradation, and presented the ability to synergistically inhibit bacteria and promote osteogenesis, possessing tremendous potential in treating implant-associated infections. STATEMENT OF SIGNIFICANCE: Infection after fracture fixation (IAFF) remains the most common and serious side effects of orthopedic surgery. Additionally, widespread antibiotic use contributes to the development of multi-drug resistant bacteria such as methicillin-resistant staphylococcus aureus (MRSA), which exacerbates IAFF treatment and prevention. IAFF treatment and prevention remain clinically challenging, so implants with dual antibacterial and osteogenic functions are in high demand. The antibacterial efficacy and osteogenic activity of low-alloyed Zn-Mg-Ag (≤0.1 wt.% Mg, Ag) alloys were investigated in vitro and in vivo. The results showed that micro addition of Mg and Ag could significantly improve osseointegration function, mechanical properties, and antibacterial performance. These quantification findings shed new light on the development and understanding of dual functional Zn-based orthopedic implants.

Use of antibiotic-impregnated beads in the treatment of lumbosacral surgical site infection: A retrospective case series

Background

Different adjuvant local-antibiotic techniques are described in management of surgical-site infections (SSIs). Antibiotic-laden polymethyl methacrylate (PMMA) spacers have been used in peri-prosthetic infections. However, their role in treatment of spinal SSIs is not well-recognised.

Methods

After approval from Institutional Review Board, we retrospectively evaluated the data of patients aged≥18 years, who were treated for SSIs of lumbo-sacral region (2010-2019). Among them, those who underwent treatment with the placement of cement beads (temporarily/permanently) were identified. This approach was utilised for post-surgical spondylodiscitis patients with significant, associated infection or abscess involving the paraspinal musculature. Only those with≥2 years' follow-up, were included.Patient demographic details, site of infection, details regarding laboratory/radiological investigations, management-protocol followed, pathogen grown, antibiotics used (their dosage and duration of use), complications encountered and outcome were recorded.

Results

13 patients [4 males, age:57.3 ± 12.4 years] were included. Seven had co-morbidities. One had upper-lumbar involvement, one sacral and others had lower-lumbar (L4/distally) disease. While 7 had recent-onset infection (≤2 months since primary surgery), 6 had chronic infection. In 2, 8, 2, and 1 patients, primary surgery was microdiscectomy, TLIF, PLF, and adult-deformity surgery, respectively.Nine underwent two-staged intervention and 4 underwent single procedure. Eleven had PMMA beads, while 2 underwent calcium sulphate bead insertion. Culture grew E coli in 3, Pseudomonas in 2; and E fecalis, K pneumoniae, MSSA and MRSA in one patient each. In 4 patients, beads were not removed. All patients underwent 2 weeks of parenteral antibiotics, followed by 8-12 weeks of oral medications. There was complete remission in all patients, except one who required additional VAC therapy.

Conclusion

Local antibiotic-laden bead application is an effective adjuvant strategy (along with debridement and systemic antibiotics) for the treatment of spinal SSI, where there is substantial infection involving the paraspinal musculature. It is cost-effective and often necessitates second procedure for bead removal.

Antibacterial and Cytotoxicity Evaluation of New Hydroxyapatite-Based Granules Containing Silver or Gallium Ions with Potential Use as Bone Substitutes

The aim of the current work was to study the physicochemical properties and biological activity of different types of porous granules containing silver or gallium ions. Firstly, hydroxyapatites powders doped with Ga³⁺ or Ag⁺ were synthesized by the standard wet method. Then, the obtained powders were used to fabricate ceramic microgranules (AgM and GaM) and alginate/hydroxyapatite composite granules (AgT and GaT). The ceramic microgranules were also used to prepare a third type of granules (AgMT and GaMT) containing silver or gallium, respectively. All the granules turned out to be porous, except that the AgT and GaT granules were characterized by higher porosity and a better developed specific surface, whereas the microgranules had very fine, numerous micropores. The granules revealed a slow release of the substituted ions. All the granules except AgT were classified as non-cytotoxic according to the neutral red uptake (NRU) test and the MTT assay. The obtained powders and granules were subjected to various antibacterial test towards the following four different bacterial strains: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli. The Ag-containing materials revealed high antibacterial activity.

Preoperative Prevention of Surgical-Site Infection in Spine Surgery

Surgical-site infections (SSI) contribute to increased hospital length of stay, readmission rates, cost, and morbidity and mortality rates. The spine service line at a suburban Level II trauma center encountered 2 SSIs among the spine fusion population within a 6-month period. This did not meet the organization's internal benchmark of zero. A pilot quasi-experimental design was used to determine whether preoperative cleansing with 2% chlorhexidine gluconate (CHG)-impregnated cloths versus current practice of bathing with 4% CHG solution would reduce SSIs. Infection rates were measured using simple percentages. Level of significance was p < .05. Outcome data showed a reduction in SSIs from 3.9% to 1.9% with use of 2% CHG-impregnated cloths. There was no significant difference found between the use of 2% CHG-impregnated cloths and 4% CHG solution (p = .524). This quality improvement change, combined with a strengthened preoperative bundle approach, has permanently been adopted within the spine service line. From October 2017 to March 2021, the spine service line has had zero SSIs within the spine fusion population.

Impact of Diabetes Mellitus on Cervical Spine Surgery for Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is commonly associated with diabetes mellitus (DM); however, the impact of DM on cervical spine surgery for OPLL remains unclear. This study was performed to evaluate the influence of diabetes DM on the outcomes following cervical spine surgery for OPLL. In total, 478 patients with cervical OPLL who underwent surgical treatment were prospectively recruited from April 2015 to July 2017. Functional measurements were conducted at baseline and at 6 months, 1 year, and 2 years after surgery using JOA and JOACMEQ scores. The incidence of postoperative complications was categorized into early (≤30 days) and late (>30 days), depending on the time from surgery. From the initial group of 478 patients, 402 completed the 2-year follow-up and were included in the analysis. Of the 402 patients, 127 (32%) had DM as a comorbid disease. The overall incidence of postoperative complications was significantly higher in patients with DM than in patients without DM in both the early and late postoperative periods. The patients with DM had a significantly lower JOA score and JOACMEQ scores in the domains of lower extremity function and quality of life than those without DM at the 2-year follow-up.

Using administrative data to determine rates of surgical site infections following spinal fusion and laminectomy procedures

OBJECTIVE

Surgical site infections (SSIs) are a serious and costly post-op complication. Generating SSI rates often requires labor-intensive methods, but increasing numbers of publications reported SSI rates using administrative data.

METHODS

Index laminectomy and spinal fusion procedures were identified using Canadian Classification of Health Interventions (CCI) procedure codes for inpatients and outpatients in the province of Alberta, Canada between 2008 and 2015. SSIs occurring in the year postsurgery were identified using the International Classification of Diseases, 10th Revision, Canada (ICD-10-CA) diagnosis and CCI procedure codes indicative of post-op infection. Rates of SSIs and case characteristics were reported.

RESULTS

Over the 8-year study period, 21,222 index spinal procedures were identified of which 12,027 (56.7%) were laminectomy procedures, with 322 SSIs identified, an SSI rate of 2.7 per 100 procedures. Of the 9,195 (43.3%) fusion procedures, 298 were identified as an SSI, an SSI rate of 3.2 per 100 procedures. This study found SSI rates increased from 2008 and 2015, and rates were the highest in the 0-18 year age group.

CONCLUSIONS

The rates reported in this study were similar to published SSI rates using traditional surveillance methods, suggesting administrative data may be a viable method for reporting SSI rates following spinal procedures. Further work is needed to validate SSIs identified using administrative data by comparing to traditional surveillance.

Zinc alloy-based bone internal fixation screw with antibacterial and anti-osteolytic properties

There is no targeted effective treatment for patients undergoing internal fixation surgery/two-stage total joint revision surgery with a high risk of postoperative infection and osteolysis, while the rate of reoperation due to infection and osteolysis remains high. In this study, we report a pioneering application of implants made of biodegradable Zn–Ag alloy with active antibacterial and anti-osteolytic properties in three classical animal models, illustrating antibacterial, anti-osteolysis, and internal fixation for fractures. The antibacterial activity of the Zn–2Ag alloy was verified in a rat femur osteomyelitis prevention model, while the anti-osteolytic properties were evaluated using a mouse cranial osteolysis model. Moreover, the Zn–2Ag based screws showed similar performance in bone fracture fixation compared to the Ti–6Al–4V counterpart. The fracture healed completely after 3 months in the rabbit femoral condyle fracture model. Furthermore, the underlying antibacterial mechanism may include inhibition of biofilm formation, autolysis-related pathways, and antibiotic resistance pathways. Osseointegration mechanisms may include inhibition of osteoclast-associated protein expression, no effect on osteogenic protein expression, and no activation of related inflammatory protein expression. The empirical findings here reveal the great potential of Zn–Ag-based alloys for degradable biomaterials in internal fixation surgery/two-stage total joint revision surgery for patients with a high risk of postoperative infection and osteolysis.

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Zn–2Ag alloy is designed for orthopedic applications.

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Zn–2Ag alloy exhibit outstanding antibacterial properties in a rat femur osteomyelitis prevention model.

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Zn–2Ag alloy exhibit outstanding anti-osteolytic properties in a mouse cranial osteolysis model.

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Zn-2Ag based screws showed reliable performance in bone fracture fixation in the rabbit femoral condyle fracture model.

Consensus statement for perioperative care in lumbar spinal fusion: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Enhanced Recovery After Surgery (ERAS) evidence-based protocols for perioperative care have led to improvements in outcomes in numerous surgical areas, through multimodal optimization of patient pathway, reduction of complications, improved patient experience and reduction in the length of stay. ERAS represent a relatively new paradigm in spine surgery.

PURPOSE

This multidisciplinary consensus review summarizes the literature and proposes recommendations for the perioperative care of patients undergoing lumbar fusion surgery with an ERAS program.

STUDY DESIGN

This is a review article.

METHODS

Under the impetus of the ERAS® society, a multidisciplinary guideline development group was constituted by bringing together international experts involved in the practice of ERAS and spine surgery. This group identified 22 ERAS items for lumbar fusion. A systematic search in the English language was performed in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Systematic reviews, randomized controlled trials, and cohort studies were included, and the evidence was graded according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Consensus recommendation was reached by the group after a critical appraisal of the literature.

RESULTS

Two hundred fifty-six articles were included to develop the consensus statements for 22 ERAS items; one ERAS item (prehabilitation) was excluded from the final summary due to very poor quality and conflicting evidence in lumbar spinal fusion. From these remaining 21 ERAS items, 28 recommendations were included. All recommendations on ERAS protocol items are based on the best available evidence. These included nine preoperative, eleven intraoperative, and six postoperative recommendations. They span topics from preoperative patient education and nutritional evaluation, intraoperative anesthetic and surgical techniques, and postoperative multimodal analgesic strategies. The level of evidence for the use of each recommendation is presented.

CONCLUSION

Based on the best evidence available for each ERAS item within the multidisciplinary perioperative care pathways, the ERAS® Society presents this comprehensive consensus review for perioperative care in lumbar fusion.

Associations Between Preoperative Hyponatremia and 30-Day Perioperative Complications in Lumbar Interbody Spinal Fusion

STUDY DESIGN

Retrospective population database study.

OBJECTIVE

To investigate the relationship of preoperative hyponatremia to postoperative morbidity and mortality in lumbar interbody fusion patients.

SUMMARY OF BACKGROUND DATA

Optimization of preoperative patient selection and perioperative management can improve patient outcomes in spinal surgery. Hyponatremia, incidentally identified in 1.7% of the US population, has previously been tied to poorer postoperative outcomes in both the general surgery and orthopedic surgery populations.

MATERIALS AND METHODS

Using the National Surgical Quality Improvement Program database, the authors identified all lumbar interbody fusion patients treated between 2012 and 2014. Patients were classified as hyponatremic (Na<135 mEq/L) or as having normal sodium levels (135-145 mEq/L) preoperatively. The primary outcome was major morbidity and secondary endpoints were prolonged hospitalization, 30-day readmission, and reoperation. Multivariable linear regression was used to find independent predictors of these outcomes.

RESULTS

Of 10,654 patients, 45.6% were male individuals, 5.5% were hyponatremic, and 4.2% experienced a major postoperative complication. On multivariable analysis, preoperative hyponatremia was independently associated with major morbidity (odds ratio, 1.22; 95% confidence interval, 1.03-1.44; P<0.05) and prolonged hospitalization (odds ratio, 1.14; 95% confidence interval, 1.02-1.27).

CONCLUSIONS

Here the authors provide the first evidence suggesting preoperative hyponatremia is an independent predictor of major morbidity after lumbar interbody fusion. Hyponatremia may represent a modifiable risk factor for improved patient care and preoperative risk counseling.

BMI Does Not Affect Complications or Patient Reported Outcomes After Lumbar Decompression Surgery

STUDY DESIGN

This is a retrospective comparative review.

OBJECTIVE

The objective of this study was to identify the influence of body mass index (BMI) on postsurgical complications and patient reported outcomes measures (PROMs) following lumbar decompression surgery.

SUMMARY OF BACKGROUND DATA

Current literature does not accurately identify the impact of BMI on postsurgical complications or outcomes.

MATERIALS AND METHODS

Records from a single-center, academic hospital were used to identify patients undergoing 1 to 3-level lumbar decompression surgery. Patients under 18 years of age, those undergoing surgery for infection, trauma, tumor, or revision, and those with <1-year follow-up were excluded. Patients were split into groups based on preoperative BMI: class I: BMI <25.0 kg/m; class II: BMI 25.0-29.9 kg/m; class III: BMI 30.0-34.9 kg/m; and class IV: BMI >35.0 kg/m. Absolute PROM scores, the recovery ratio and the percent of patients achieving minimum clinically important difference between groups were compared and a multiple linear regression analysis was performed.

RESULTS

A total of 195 patients were included with 34 (17.4%) patients in group I, 80 (41.0%) in group II, 49 (25.1%) in group III, and 32 (16.5%) in group IV. Average age was 60.0 (58.0, 62.0) years and average follow-up was 13.0 (12.6, 13.4) months. All patients improved significantly within each group, except for class III and class IV patients, who did not demonstrate significant improvements in terms of Mental Component Score (MCS-12) scores (P=0.546 and 0.702, respectively). There were no significant differences between BMI groups for baseline or postoperative PROM values, recovery ratio, or the percent of patients reaching minimum clinically important difference. Multiple linear regression analysis revealed that BMI was not a significant predictor for change in outcomes for any measure. The 30-day readmission rate was 6.2% and overall revision rate at final follow-up was 5.1%, with no significant differences between groups.

CONCLUSION

This study's results suggest that BMI may not significantly affect complications or patient outcomes at 1-year in those undergoing lumbar decompression surgery.

LEVEL OF EVIDENCE

Level III.

Biodegradable Zn-Cu alloys show antibacterial activity against MRSA bone infection by inhibiting pathogen adhesion and biofilm formation

Bone and joint-related infections remain the primary and most critical complications of orthopedic surgery. We have innovatively prepared Zn-Cu alloys to achieve outstanding material and antibacterial properties. In this study, we systematically assessed the material properties and antibacterial activity of these Zn-Cu alloys. Our results showed that the Zn-2Cu alloy had the best mechanical properties, biocompatibility, and osteogenic properties. Findings of microbial cultures, CLSM, SEM, and TEM indicated that Zn-2Cu alloy can inhibit both coagulase-positive and coagulase-negative staphylococci, as well as antibiotic-resistant strains (MRSA and MRSE), by preventing the bacteria adhesion and the biofilm formation. Zn-2Cu alloy could broadly affect the expression of MRSA genes associated with adhesion, autolysis, biofilm formation, virulence, and drug resistance. A rat femur intramedullary nail infection-prevention model was established and the Zn-2Cu alloy-treated group showed significant antibacterial activity against MRSA and reduced the inflammatory toxic side-effects and infection-related bone loss. Collectively, our results indicate the potential utility of Zn-Cu alloy implants with 2 wt% Cu in treating orthopedic infections. Statement of significance: Osteomyelitis is a serious complication of orthopedic surgeries. Wide use of antibiotics contributes to the appearance of multi-drug resistant strains like methicillin-resistant staphylococcus aureus (MRSA). Alternatively, anti-osteomyelitis implants with broad-spectrum antibacterial properties can be favorable. Here, the antibacterial performance of biodegradable Zn-Cu alloys was evaluated with four different bacteria strains including antibiotic-resistant strains (MRSA and MRSE). Zn-Cu alloys exert excellent bacterial killing capability in all strains. In a rat femur infection model, the alloy showed significant antibacterial activity against MRSA and reduced inflammatory toxic side-effects as well as infection-related bone loss. The antibacterial property of Zn-2Cu alloy was associated with inhibition of gene expression related to wall synthesis, adhesion, colonization, biofilm formation, autolysis, and secretion of virulence factors in MRSA.

Assessment of Rod Material Types in Spine Surgery Outcomes: A Systematic Review

BACKGROUND

Lumbar spine fusion surgery is traditionally performed with rigid fixation. Because the rigidity is often supraphysiologic, semirigid rods were developed. To the best of our knowledge, a comprehensive evaluation of rod material type on surgical outcomes has yet to be conducted.

METHODS

A systematic review based on PRISMA guidelines was conducted across 3 electronic databases. After examination for inclusion and exclusion criteria, data were extracted from the studies.

RESULTS

Seventeen studies, including 1399 patients, were included in this review. The mean rigid rod fusion rate is 92.2% and 95.5% for semirigid rods (P = 0.129). The mean improvement in back pain was 60.6% in rigid rods and 71.6% in semirigid rods. The improvement in leg pain was 81.9% and 77.2%, respectively. There were no differences in visual analog scale back pain score (P = 0.098), visual analog scale leg pain score (P = 0.136), or in functional improvement between rigid and semirigid rods (P = 0.143). There was no difference (P = 0.209) in the reoperation rate between rigid rods (13.1%) and semirigid rods (6.5%). There was a comparable incidence of adjacent segment disease (3%), screw fracture (1.7%), and wound infection (1.9%) between rod material types.

CONCLUSIONS

There is a moderate level of evidence supporting that surgical intervention results in high fusion rates regardless of rod material type. Surgical intervention improves back pain, leg pain, and function, with neither material type showing clear superiority. There are comparable rates of reoperation, development of adjacent segment disease, development of mechanical complications, and incidence of infection in both rigid and semirigid rods. Further studies regarding rod material type are warranted.

Risk-benefit analysis of wound drain usage in spine surgery: a systematic review and meta-analysis with evidence summary

STUDY DESIGN

Systematic review, meta-analysis, evidence synthesis.

OBJECTIVES

To analyse the literature evidence available to support the usage of wound drain in various scenarios of spine surgery and provide an evidence summary on the surgical practice.

MATERIALS AND METHODS

We conducted independent and duplicate electronic database searches adhering to PRISMA guidelines in PubMed, Embase, and Cochrane Library till April 2020. Quality appraisal was done as per Cochrane ROB tool, and evidence synthesis was done as per GRADE approach. Five domains of spine surgery with associated key questions were identified. Evidence tables were generated for each question and critical appraisal done as per the GRADE approach.

RESULTS

Twenty-three studies (9-RCTs, 4-prospective studies, 10-retrospective studies) were included. Analysis of studies in cervical spine either by anterior or posterior approach and single/multilevel thoracolumbar spinal surgeries did not show any evidence of reduction in surgical site infection (SSI) or haematoma formation with the use of drain. Deformity correction surgeries and surgeries done for trauma or tumour involving spine also did not find any added benefit from the use of wound drains despite increasing the total blood loss.

CONCLUSION

Evidence from this review suggests that routine use of drain in various domains of spine surgery does not reduce the risk of SSI and their absence did not increase the risk of haematoma formation. The current best evidence is presented with its limitations. High-quality studies to address their use in spine surgeries in cervical, trauma, and tumour domains are required to further strengthen the evidence synthesised from available literature.

Preoperative Hyponatremia and Perioperative Complications in Cervical Spinal Fusion

OBJECTIVE

Preoperative patient optimization is increasingly recognized as key to good surgical outcomes. Preoperative hyponatremia is a modifiable risk factor linked to poorer postoperative outcomes in other surgical fields. We provide the first investigation of the association of preoperative hyponatremia with morbidity and mortality in patients undergoing cervical spine surgery.

METHODS

We queried the National Surgical Quality Improvement Program registry for patients who underwent cervical spine fusion. Preoperative serum sodium levels were classified as normal (135-145 mEq/L) or hyponatremic (<135 mEq/L); hypernatremic patients were excluded from the analysis. Multivariable logistic analyses using a multiple imputations methodology were performed to determine significant predictors of major morbidity and mortality (MMM).

RESULTS

We included 20,817 patients, of whom 5.2% were hyponatremic at presentation. Preoperative hyponatremia was a significant predictor of MMM (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.09-1.39), mortality (OR, 1.36; 95% CI, 1.03-1.77), major morbidity (OR, 1.24; 95% CI, 1.10-1.40), and odds of prolonged hospitalization (OR, 1.13; 95% CI, 1.04-1.23). Other significant predictors of MMM included age, undergoing an emergent versus nonemergent operation, having chronic obstructive pulmonary disease, having disseminated malignancy, being functionally dependent, presenting with sepsis or septic shock, and having an American Society of Anesthesiologists status of 3, 4, or 5. Similar results were seen in analyses using only complete cases and in sensitivity analyses.

CONCLUSIONS

Using the National Surgical Quality Improvement Program database, hyponatremia is observed in approximately 1 in every 20 patients undergoing cervical spine fusion. More importantly, it is a predictor of mortality, major morbidity, and prolonged hospitalization. From a systems-level perspective, preoperative hyponatremia may therefore represent a point of intervention for preoperative patient optimization.

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.

Predictive value of post-operative neutrophil/lymphocyte count ratio for surgical site infection in patients following posterior lumbar spinal surgery

OBJECTIVE

Surgical site infection (SSI) is a common complication in patients following posterior lumbar spinal surgery. Various laboratory data such as laboratory parameters derived neutrophil/lymphocyte count ratio (NLR), have been applied for the prediction of SSI, but more studies are necessary to evaluate the significance of these indicators. Here, our study aims to investigate the predictive value of total white blood cells (WBCs), count and percentages of neutrophils and leukocytes, NLR, and C-reactive protein (CRP) for surgical site infection (SSI) in patients after posterior lumbar spinal surgery.

METHODS

A total of 293 patients who underwent posterior lumbar spinal surgery were enrolled in this study. Each patient's medical history was retrospectively reviewed, and patients were divided into the deep SSI group (n = 13) and the non-SSI group (n = 280). Laboratory data including total WBC, count and percentages of neutrophils and leukocytes, NLR at 1 week before the operation and the 4 and 7 days post-operation, and CRP at 4 and 7 days post-operation were analysed between the SSI and non-SSI groups. Moreover, predictive power and cut-off of NLR for SSI were determined by receiver operating characteristic curve (ROC) results.

RESULTS

Data revealed that the medians of NLR were markedly increased in the SSI group as compared to that in non-SSI group at 4 days (p = 0.011) and 7 days (p = 0.047) post-operation. Moreover, the neutrophil percentage was also dramatically increased in the SSI group at both 4 and 7 days post-operation (p = 0.010 and p = 0.030) respectively compared to the non-SSI group. However, no significant difference was observed between the groups 1 week before the operation. ROC results showed that NLR at 4 days (cut-off >5.19; sensitivity: 61.5%; specificity: 77.6%; AUC = 0.708) and 7 days (cut-off >3.85; sensitivity: 69.2%; specificity: 62.7%; AUC = 0.663) post-operation could significantly discriminate the SSI and non-SSI groups. Logistic regression analysis showed that NLR at both post-operative time points (OR = 1.218; p = 0.003 and OR = 1.296; p = 0.048) could be valuable predictors for SSI.

CONCLUSION

NLR at 4 and 7 days post-operation are valuable laboratory predictors for SSI in patients with posterior lumbar spinal surgery.