Postoperative spinal wound infection: a review of 2,391 consecutive index procedures

Intra-operative imaging for spinal level localisation in lumbar surgery

Study Design: Retrospective review of the practice of 3 surgeons in a single centre during a 1-year period. Objective: We aimed to investigate our adherence to the Society of British Neurological Surgeons (SBNS) guidelines regarding intra-operative imaging during lumbar surgery and to determine if this has any impact on length of surgery or complications rates, in particular rates of wrong-level surgery. Background: The SBNS recommends three x-rays for intra-operative spinal localisation - one prior to incision, the second after exposure of the laminae and before the commencement of decompression, and the third at the end of the operation to confirm the adequacy of decompression. At our centre, surgeon A performs x-rays 1 and 3 routinely, and x-ray 2 in cases where the anatomy is uncertain, surgeon B performs x-ray 2 only, and the practice of surgeon C varies depending on the complexity of cases. Method: We reviewed the surgical logbooks of 3 consultant neurosurgeons in our centre for the 1-year period between October 2015 and October 2016. Our study included 301 patients who had undergone lumbar decompression or lumbar discectomy during this period. Results: There were no cases of wrong-level surgery. The incorrect spinal level was initially exposed in 13 cases (4.3%). 10 of these had x-ray 2 only, 1 had x-ray 1, 1 had x-rays 1 and 2, and 1 had all 3 x-rays. Surgeon B performed 8 of these cases, four were performed by surgeon C, and 1 by surgeon A. The median duration of surgery was 80 minutes for lumbar decompression and 67.5 minutes for lumbar discectomy. The median duration of surgery in patients in whom the wrong level was initially exposed was 85 minutes for lumbar decompression and 80 minutes for lumbar discectomy. Conclusion: Performance of the 3 recommended x-rays may increase the identification of wrong-level exposures before the commencement of decompression and may reduce the length of surgery.

Postoperative Surgical Site Infection After Spine Surgery: An Update From the Scoliosis Research Society (SRS) Morbidity and Mortality Database

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

Analyze the Scoliosis Research Society (SRS) Morbidity & Mortality (M&M) database to assess the incidence and characteristics related to postoperative surgical site infection (SSI) after spinal deformity surgery.

SUMMARY OF BACKGROUND DATA

Infections involving spinal instrumentation are associated with greater rates of disability. Rates of postoperative SSI after spinal deformity surgery range from 1.9% to 4.4%. Postoperative SSI rates of 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis have been reported.

METHODS

The SRS M&M database was evaluated to define patient demographics, perioperative factors, and infection characteristics of spinal deformity patients with postoperative spine infections after deformity surgery in 2012.

RESULTS

Of the 47,755 procedures reported to the SRS in 2012, there were 578 (1.2%) diagnosed SSIs. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p < .0001) or spondylolisthesis (2.4% vs. 1.1%, p < .0001). Spinal fusions were performed in 86.3% of patients, 75.1% of which were performed posteriorly. Osteotomies were performed in 30.1% of patients. Deep infections below the fascia accounted for 68.0% of infections. Methicillin-sensitive (41.9%) and methicillin-resistant (17.0%) Staphylococcus aureus were the most commonly isolated pathogens, whereas gram-negative bacteria accounted for 25.4% of cases. Long-term antibiotic suppression was required in 18.9% of patients, and overall complications from antibiotics occurred in 4.5% of patients. Operative treatment was required in 81.8% of SSI cases.

CONCLUSION

SSIs occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery.

LEVEL OF EVIDENCE

Level III.

Risk Factors for Positive Cultures in Presumed Aseptic Revision Spine Surgery

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

To report culturing patterns and results in the setting of presumed aseptic revision spinal surgery.

SUMMARY OF BACKGROUND DATA

The indications for obtaining cultures in revision spinal surgery remain unclear in the absence of a definitive diagnosis of infection. Culture results and risk factors for having positive cultures in this setting have not been previously studied.

METHODS

We retrospectively reviewed 595 consecutive revision spine surgeries performed by four senior spine surgeons between 2008 and 2013. Preoperative workup revealed the diagnosis of infection in 17 cases which were excluded from review. The remaining 578 presumed aseptic cases were included. Univariate and multivariate analyses were performed to identify variables associated with obtaining cultures and risk factors for positive cultures.

RESULTS

Cultures were obtained in 112 (19.4%) cases and were positive in 40.2%. Pseudarthrosis was the most common revision diagnosis when cultures were obtained (49.1%) and Propionibacterium acnes was the most common organism isolated from positive cultures (48.8%). Regarding culture results, multivariate analysis demonstrated that male sex (odds ratio [OR] = 3.4) and pseudarthrosis (OR = 4.1) were significantly associated with having positive cultures while fusion procedures (OR = 0.3) were negatively correlated, with area under the curve (AUC) 0.71.

CONCLUSION

Unexpected positive cultures occurred commonly and P. acnes was the predominant isolated organism. Male sex, pseudarthrosis, and non-fusion cases predicted positive cultures. Considering these results, we recommend cultures be obtained in revision cases for pseudarthrosis, even in the setting of negative infectious work-up preoperatively.

LEVEL OF EVIDENCE

4.

Complications, Results, and Risk Factors of Spinal Fusion in Patients With Myelomeningocele

STUDY DESIGN

Retrospective prognostic study.

OBJECTIVE

The purpose of this study assess was to assess the results of spinal fusion and identify factors associated with the development of post-spinal fusion infections in patients with myelomeningocele.

BACKGROUND

Surgical correction of neuromuscular scoliosis secondary to myelomeningocele is known to be associated with a high complication rate.

METHODS

A retrospective cohort study design was used to collect data on patients with myelomeningocele who underwent spinal fusion between the years of 1997-2013. Only subjects with a minimum of two years of continuous follow-up were included in the study. Demographic, surgical, clinical, and radiographic variables of interest were collected. Univariate and multivariable logistic regression analyses were used to identify factors predictive of an infection. Linear mixed model regression analyses were used to analyze postsurgical changes in radiographic parameters.

RESULTS

Of the 33 subjects included in the study, 33.3% developed a postoperative infection. Overall, 69.0% of patients achieved a >50% correction of primary curvature at the one-month time point. Of the measured variables, lumbar and thoracolumbar kyphosis (odds ratio: 10.9, 95% confidence interval [CI]: 1.2-158.3, p = .0465) and a low preoperative hematocrit odds ratio per 1% increase, 0.7 (95% CI: 0.5-0.9, p = .0145) were associated with developing a postoperative infection. There was a significant improvement in the proportion of subjects with a pelvic obliquity measurement <5° one month postsurgery (p = .0339), kyphosis (p = .0401), and Cobb angle of the primary curvature across all time points (p <.0001).

CONCLUSION

Type of procedure, neurosegmental level, transfusion rates, age at surgery, gender, length of operation, preoperative urinary tract infection, estimated blood loss, and the number of levels fused were not modifiable risk factors for future complications for patients with scoliosis secondary to myelomeningocele, whereas lumbar and thoracolumbar kyphosis or low hematocrit levels may lead to an increased risk for developing a postspinal fusion infection.

LEVEL OF EVIDENCE

Level II.

Outcomes of decompression and fusion for treatment of spinal infection

OBJECTIVE

Spine infection including vertebral osteomyelitis, discitis, paraspinal musculoskeletal infection, and spinal abscess refractory to medical management poses significant challenges to the treating physician. Surgical management is often required in patients suffering neurological deficits or spinal deformity with significant pain. To date, best practices have not been elucidated for the optimization of health outcomes and resource utilization in the setting of surgical intervention for spinal infection. The authors conducted the present study to assess the magnitude of reoperation rates in both fusion and nonfusion groups as well as overall health resource utilization following surgical decompression for spine infection.

METHODS

The authors performed an analysis using MarketScan (2001–2015) to identify health outcomes and healthcare utilization metrics of spine infection following surgical intervention with decompression alone or combined with fusion. Adult patients underwent surgical management for primary or secondary spinal infection and were followed up for at least 12 months postoperatively. Assessed outcomes included reoperation, healthcare utilization and payment at the index hospitalization and within 12 months after discharge, postoperative complications, and infection recurrence.

RESULTS

A total of 2662 patients in the database were eligible for inclusion in this study. Rehospitalization for infection was observed in 3.99% of patients who had undergone fusion and in 11.25% of those treated with decompression alone. Reoperation was needed in 12.7% of the patients without fusion and 8.16% of those with fusion. Complications within 30 days were more common in the nonfusion group (24.64%) than in the fusion group (16.49%). Overall postoperative payments after 12 months totaled $33,137 for the nonfusion group and $23,426 for the fusion group.

CONCLUSIONS

In this large cohort study with a 12-month follow-up, the recurrence of infection, reoperation rates, and complications were higher in patients treated with decompression alone than in those treated with decompression plus fusion. These findings along with imaging characteristics, disease severity, extent of bony resection, and the presence of instability may help surgeons decide whether to include fusion at the time of initial surgery. Further studies that control for selection bias in appropriately matched cohorts are necessary to determine the additive benefits of fusion in spinal infection management.

Vacuum-assisted closure combined with a closed suction irrigation system for treating postoperative wound infections following posterior spinal internal fixation

BACKGROUND

Wound infections after posterior spinal surgery are a troublesome complication; patients are occasionally forced to remove the internal fixation device, which can lead to instability of the spine and injury to the spinal cord. The purpose of this study was to evaluate the efficacy of modified vacuum-assisted closure (VAC) for treating an early postoperative spinal wound infection.

METHODS

We conducted a retrospective study of 18 patients with wound infections after posterior spinal surgery from 2014 to 2017 at a single tertiary center. All patients included in the study received modified VAC treatment (VAC combined with a closed suction irrigation system, CSIS) until the wound satisfied the secondary closure conditions. Detailed information was obtained from the medical records.

RESULTS

Wound size decreased significantly after 1 week of the modified VAC treatment. Three patients were treated with VAC three times and one patient received the VAC treatment four times; the remaining patients received the VAC treatment twice. The patients had excellent wound beds after an average of 8 days. The wound healed completely after an average of 17 days, and the average hospital stay was 33 days. There was no recurrence of infection at the 1-year follow-up.

CONCLUSIONS

This study demonstrates that VAC combined with a CSIS is a safe, reliable, and effective method to treat a wound infection after spinal surgery. This improved VAC procedure provides an excellent wound bed to facilitate wound healing and shorten the hospital stay.

Prognosis of deep infection in spinal surgery using implants, treated by retention, removal of bone graft and lengthy antibiotherapy

OBJECTIVE

Surgical site infections (SSIs) are complications that predispose to a high risk of unfavourable surgical outcomes. The aim of this study was to assess the SSI rate in this type of patients and their prognosis with similar treatment.

MATERIALS AND METHODS

A retrospective case series of 799 patients above 18 years old with spinal instrumentation surgery, between January 2010 and December 2014 in the traumatology and orthopaedic surgery department of our institution. All patients with SSIs were treated by debridement, graft replacement, retention of the instrumentation and lengthy courses of antimicrobial therapy. The patients were followed up for a period of 12 months.

RESULTS

Of all the patients with arthrodesis, 32 (4%) had spinal SSIs. Three patients were lost to follow-up. The final sample analyzed comprised 29 cases, with a median age of 54.9 years (IQR, 45.7-67 years) and a Charlson comorbidity index of 2.0 (IQR; 0-3). A microbiological diagnosis was obtained in 75.8% of the cases. Of these, the ISSs were monomicrobial in 68.2% and polymicrobial in 31.8%. Once treatment had been completed, 96% were cured without sequelae, and the rate of recurrence and reoperation was 4%.

CONCLUSIONS

Treatment based on debridement, retention of the instrumentation, graft replacement and lengthy courses of antimicrobial therapy seems a very effective strategy in the treatment of patients with deep surgical site infection in spine surgery.

Surgical Site Infection in Spine Surgery: Who Is at Risk?

STUDY DESIGN

Retrospective literature review of spine surgical site infection (SSI).

OBJECTIVE

To perform a review of SSI risk factors and more specifically, categorize them into patient and surgical factors.

METHODS

A review of published literature on SSI risk factors in adult spine surgery was performed. We included studies that reported risk factors for SSI in adult spinal surgery. Excluded are pediatric patient populations, systematic reviews, and meta-analyses. Overall, we identified 72 cohort studies, 1 controlled-cohort study, 1 matched-cohort study, 1 matched-paired cohort study, 12 case-controlled studies (CCS), 6 case series, and 1 cross-sectional study.

RESULTS

Patient-associated risk factors-diabetes mellitus, obesity (body mass index >35 kg/m²), subcutaneous fat thickness, multiple medical comorbidities, current smoker, and malnutrition were associated with SSI. Surgical associated factors-preoperative radiation/postoperative blood transfusion, combined anterior/posterior approach, surgical invasiveness, or levels of instrumentation were associated with increased SSI. There is mixed evidence of age, duration of surgery, surgical team, intraoperative blood loss, dural tear, and urinary tract infection/urinary catheter in association with SSI.

CONCLUSION

SSIs are associated with many risk factors that can be patient or surgically related. Our review was able to identify important modifiable and nonmodifiable risk factors that can be essential in surgical planning and discussion with patients.

Wound Closure After Posterior Multi-level Lumbar Spine Surgery: An Anatomical Cadaver Study and Technical Note

Meticulous attention to wound closure in posterior lumbar spine surgery is an important principle in reducing surgical site infections. We detail standardized wound closure used for posterior lumbar spine surgery at a tertiary care referral center and illustrate this as a step-by-step cadaveric dissection. The lumbar spine of a cadaveric specimen (male, 73 years at death) was used for dissection. Standardizing wound closure in posterior lumbar spine surgery may help limit wound complications and infection. Some key points of our technique, as demonstrated on a cadaveric specimen, include separating fascial compartments, avoiding suture abscesses, and creating a tension-free wound.

Time to Diagnosis and Treatment of Surgical Site Infections in Foot and Ankle Surgery

BACKGROUND

The time at which patients typically present with surgical site infections (SSI) following foot and ankle surgery has not been characterized. The primary aim of this study was to quantify the time to definitive treatment of SSIs.

METHODS

We performed a retrospective review of 1933 foot and ankle procedures in 1632 patients from 2011 through 2015. Demographic and surgical data were collected. Time to presentation in cases diagnosed with postoperative wound complications or SSIs was analyzed. Wound complications were defined as any case with concerning wound appearance that subsequently resolved with antibiotic therapy alone. SSIs were defined as cases requiring operative irrigation and debridement (I&D) for successful definitive management.

RESULTS

A total of 1569 procedures met inclusion criteria, with 17 SSIs (1.1%) and 63 wound complications (4.0%). Time between surgery and definitive treatment in the SSI group was significantly greater than in the wound complication group (28.2 ± 9.1 vs 13.4 ± 4.7 days, P < .00001). Eleven (64.7%) cases in the SSI group failed a trial of antibiotics prior to I&D, and 6 (35.3%) cases did not receive antibiotics prior to I&D. Antibiotic treatment prior to I&D did not significantly decrease the yield of intraoperative wound cultures (70% vs 100%, P = .51).

CONCLUSION

In our cohort of patients, the time to diagnosis and treatment of SSIs was longer than that of wound complications. SSIs requiring operative intervention did not present until an average of 4 weeks after surgery. These data are of some benefit in trying to define and understand SSI.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Risk factors for perioperative morbidity in spine surgeries of different complexities: a multivariate analysis of 1,009 consecutive patients

BACKGROUND CONTEXT

There is a broad spectrum of complications during or after surgical procedures, with differing incidences reported in the published literature. Heterogeneity can be explained by the lack of an established evidence-based classification system for documentation and classification of complications in a standardized manner.

PURPOSE

The objective of this study was to identify predictive risk factors for perioperative and early postoperative morbidities in spine surgeries of different complexities in a large cohort of consecutive patients.

STUDY DESIGN

This study is a retrospective case series.

OUTCOME MEASURES

The outcome measures are the occurrence of perioperative and early postoperative morbidities.

METHODS

A classification of surgical complexity (Grades I-III) was created and applied to 1,009 patients who consecutively underwent spine surgery at a single university hospital. The incidence and the type of perioperative and early postoperative morbidities were documented. Multivariate binary logistic regression analyzed risk factors for (1) hospital stay of ≥10 days, (2) intermediate care unit (IMC) stay of ≥24 hours, (3) blood loss of >500 mL, and occurrence of a (4) surgical or (5) medical morbidity.

RESULTS

A deviation from the regular postoperative course (defined as "morbidity") included surgical reasons, such as relapse of symptoms of any kind (3.3%), wound healing problems (2.4%), implant-associated complications (1.6%), postoperative neurologic deficits (1.5%), infection (1.5%), fracture (0.8%), and dural tear in need of revision (0.6%). Medical reasons included anemia (1.8%), symptomatic electrolyte derailment (1.0%), and cardiac complications (0.7%), among others. An independent risk factor associated with a surgical reason for an irregular postoperative course was male gender. Risk factors associated with a medical reason for an irregular postoperative course were identified as preoperatively high creatinine levels, higher blood loss, and systemic steroid use. Independent risk factors for a prolonged hospitalization were preoperatively high C-reactive protein level, prolonged postoperative IMC stay, and revision surgery. Spinal stabilization or fusion surgery, particularly if involving the lumbosacral spine, age, and length of surgery were associated with blood loss of >500 mL. Higher surgical complexity, involvement of the pelvis in instrumentation, American Society of Anesthesiologists Grade ≥III, and preoperatively higher creatinine levels were associated with a postoperative IMC stay of >24 hours.

CONCLUSIONS

The present study confirms several modifiable and non-modifiable risk factors for perioperative and early postoperative morbidities in spine surgery, among which surgical factors (such as complexity, revision surgery, and instrumentation, including the pelvis) play a crucial role. A classification of surgical complexity is proposed and validated.

Impact of Hemodialysis on Surgical Outcomes and Mortality Rate after Lumbar Spine Surgery: A Matched Cohort Study

Introduction

Despite ongoing improvements in both dialysis and surgical techniques, spinal surgery in patients undergoing hemodialysis (HD) is a challenge to surgeons because of the high mortality rate. However, no previous studies have examined clinical outcomes after lumbar surgery in HD patients. The purpose of this study is to compare clinical outcomes and complication rates after lumbar spinal surgery in patients with or without hemodialysis.

Methods

This retrospective, matched cohort study was conducted to compare surgical outcomes between HD vs non-HD patients who underwent lumbar surgery at our hospital. Controls were individually matched to cases at a ratio of 1:2. Clinical outcomes, complications, and mortality rates were compared between the two groups.

Results

Twenty-nine patients in the HD group and 57 in the non-HD group were included in the current study. Five patients in the HD group died during the follow-up period, whereas no patients died in the non-HD group (mortality rate, 17.2% vs. 0%, P = 0.003). Japanese Orthopaedic Association (JOA) scores were significantly less improved in the HD group than in the non-HD group (11.9 vs. 14.2 preoperatively, P = 0.001; 19.9 vs. 25.1 at final follow-up, P < 0.001). Five patients underwent repeat surgery in the HD group, which was significantly higher than the non-HD group (17.2% vs. 3.5%, P = 0.041).

Conclusions

The current study indicates that patients undergoing HD had poor outcomes after lumbar spinal surgery. Moreover, 5 of 29 patients died within a mean 2.4-years follow-up. The indications for lumbar spine surgery in HD patients must be carefully considered because of poor surgical outcomes and high mortality rate.

The Difference in Surgical Site Infection Rates Between Open and Minimally Invasive Spine Surgery for Degenerative Lumbar Pathology: A Retrospective Single Center Experience of 1442 Cases

BACKGROUND

Surgical site infection (SSI) in spinal surgery contributes to significant morbidity and healthcare resource utilization. Few studies have directly compared the rate of minimally invasive surgery (MIS) SSI with open surgery.

OBJECTIVE

To investigate whether MIS techniques had a lower SSI rate in degenerative lumbar procedures as compared with traditional open techniques.

METHODS

A single-center, retrospective review of a prospectively collected database was queried from January 2013 to 2016 for adult patients who underwent lumbar decompression and/or instrumented fusion for which the surgical indication involved degenerative disease. The SSI rate was determined for all procedures as well as in the open and minimally invasive groups. Risk factors associated with SSI were also reviewed for each patient.

RESULTS

A total of 1442 lumbar spinal procedures were performed during this time period. Of these, there were 961 MIS and 481 open (67% vs 33%, respectively). The overall SSI rate was 1.5% (21/1442). The surgical site infection rate for MIS was less than open techniques (0.5% vs 3.3%; P = .0003). For decompression only, the infection rate for MIS and open was 0.4% vs 3.9% (P = .04), and for decompression with fusion it was 0.7% vs 2.6%, respectively (P = .68).

CONCLUSION

Our study demonstrates a significant 7-fold reduction in SSIs when comparing MIS with open surgery. This significance was also demonstrated with a 10-fold reduction for procedures involving decompression alone. Procedures that require fusion as well as decompression showed a trend towards a decreased infection rate that did not reach clinical significance.

Do Preoperative Corticosteroid Injections Increase the Risk for Infections or Wound Healing Problems After Spine Surgery?: A Swiss Prospective Multicenter Cohort Study

STUDY DESIGN

A prospective multicenter cohort study.

OBJECTIVES

This study evaluates the risk for surgical site infections (SSIs) or wound healing problems (WHPs) in patients who underwent corticosteroid injection before lumbar decompression surgery.

SUMMARY OF BACKGROUND DATA

Corticosteroid injections are often used for the treatment of the degenerated spine. However, their well-known immunosuppressive effects could increase the risk for local infections, particularly if a surgical intervention follows the injection rapidly.

METHODS

The Swiss Lumbar Stenosis Outcome Study (LSOS), which is a prospective multicenter cohort study of patients with symptomatic lumbar spinal stenosis, was used as database. Of 743 patients, 422 patients underwent surgery and were eligible for the study. Ten patients (2.4%) were revised for either SSIs (n = 6) or WHPs (n = 4). A control group (n = 19) was constructed matched according to age, sex, diabetes, and body mass index (BMI). Odds ratios (ORs) were calculated by using a conditional logistic regression model to quantify the risk of SSI or WHP after preoperative corticosteroid injection. Subgroup analysis was performed for patients with injection within 0 to 3 months before surgery, 0 to 6 months before surgery, or any injection at all before surgery.

RESULTS

Within this cohort, no significant association could be found between preoperative corticosteroid injection and postoperative SSI or WHP in patients with corticosteroid injections within 0 to 3 months before surgery [OR = 0.36, 95% confidence interval (95% CI) 0.04-3.22], 0 to 6 months before surgery (OR = 0.69 95% CI 0.14-3.49), or any time before surgery (OR = 0.43, 95% CI 0.04-3.22).

CONCLUSION

Within the here investigated cohort, the risk of SSIs or WHPs following lumbar spinal decompression surgery seems not highly associated with preoperative corticosteroid injections. However, the safe time interval between corticosteroid infiltrations and surgery remains unknown, should not be decreased incautiously, and is the subject of further research.

LEVEL OF EVIDENCE

2.

Value of procalcitonin as a marker of surgical site infection following spinal surgery

AIM

To compare the value of Procalcitonin (PCT) as a marker of surgical site infection to other inflammatory markers, including C-Reactive Protein (CRP), White Cell Count (WCC) and Erythrocyte Sedimentation Rate (ESR) in patients undergoing a number of spinal procedures. This study also aims to describe the biokinetic profile of the above-named markers in patients developing surgical site infection and those remaining infection-free post-operatively.

METHODS

200 patients undergoing four routine elective spinal procedures were included for analysis. All patients had blood specimens taken at baseline, day 1, 2, 3, 4 and 5 post-operatively for analysis of PCT, CRP, ESR and WCC levels. All patients were monitored for early surgical site infection. Patients with other sources of infection in the early postoperative period were excluded.

RESULTS

Procalcitonin was the most sensitive and specific marker for the detection of surgical site infection in the immediate post-operative period with sensitivity and specificity of 100% and 95.2% respectively. Although Procalcitonin is an inflammatory marker, extent of surgical physiological insult did not alter its biokinetics as opposed to the other inflammatory markers making it a valuable marker of infection.

CONCLUSION

Procalcitonin was found to be superior to the other inflammatory markers investigated in this study as a marker for early surgical site infection in patients undergoing spinal surgery.

The effectiveness of pedicle screw immersion in vancomycin and ceftriaxone solution for the prevention of postoperative spinal infection: A prospective comparative study

OBJECTIVE

The aim of this study was to evaluate the efficacy of the local application of vancomycin hydrochloride (HCl)-ceftriaxone disodium hemiheptahydrate onto implants before using them to prevent postoperative infection.

METHODS

The study included 239 patients (153 women and 86 men; mean age: 48.23 ± 16.77 years) who had thoracolumbar stabilization with transpedicular screws. All surgeries were performed by the same surgeon. Patients were divided into two groups. In the group 1 (n = 104), implants were bathed in a solution of local prophylactic antibiotics for 5 seconds just before implantation. In the group 2 (n = 135), implants were not bathed before implantation. Local antibiotics used in the study was effective against gram positive bacteria (including methicillin resistant Staphylococcus aureus) and gram negative bacteria. The rate of surgical site infection and wound healing time were compared between the groups.

RESULTS

A total of 10 patients (4.1%) had deep wound infection and 20 (8.4%) had superficial infection. The most common bacteria was Staphylococcus aureus. One patient died 21 days after the surgery because of sepsis. The wound healed in a mean of 9.66 ± 2.04 days in patients who had no infection and in 32.33 ± 19.64 days in patients with infection (p < 0.001). The patients in group 1 had significantly less deep infection than the patients in group 2 (p < 0.05). However, there was no statistically significant difference between the groups for superficial infection. Patients with vertebral fracture had significantly lower deep infection rate in group 1. The deep infection rate of group 1 patients with diabetes, with bleeding of more than 2000 mL, transfused with blood transfusions above 3 units and with dural injury was significantly lower than those in the group 2. None of the patients had allergic reactions to the drugs used for local prophylaxis.

CONCLUSIONS

This study shown that bathing implants in antibiotics solution was an effective local prophylactic method to prevent deep infections in spinal surgeries with instrumentation.

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Incidence and risk factors of wound complications in long segment instrumented thoracolumbar spinal fusions: a retrospective study

BACKGROUND

This is a retrospective analysis of prospectively collected data. Our objective was to determine the incidence and assess the risk factors associated with surgical site wound complications in long segment (7+ vertebrae) instrumented thoracolumbar fusions. Surgical site complications lead to patient morbidity, increased financial burden, and further medical intervention. Risk factors for wound complications in spinal surgery include patient factors such as obesity and diabetes, and surgical factors such as operative time and procedure type. Fusion with instrumentation is one of the strongest associated risk factors in the literature.

METHODS

A comprehensive search of the National Surgical Quality Improvement Program (NSQIP) from 2005 to 2014 was performed, selecting cases based on Current Procedural Terminology (CPT) codes. Cases were then stratified based on the presence of one of the following wound complications: superficial surgical site infection, deep surgical site infection, organ space infection, and wound dehiscence. Univariate and bivariate analyses were performed to determine risk factors.

RESULTS

A total of 2,548 cases were identified, and the most common diagnoses were scoliosis (29%), spondylosis (17%) and spinal stenosis (14%). Overall, 4.24% of cases had at least one wound complication. Identified risk factors include obesity, preoperative transfusion, preoperative wound infection, and operative time. Associated outcomes include stroke with neurological deficit, perioperative transfusion, deep vein thrombosis (DVT), sepsis, septic shock, readmission, reoperation, and longer length of hospital stay. Many of these variables are independently associated with a wound complication.

CONCLUSIONS

Our analysis of the NSQIP demonstrated risk factors and complications associated with wound infections in the setting of long segment fusions (7+ levels). These findings may aid surgeons in determining a patient's risk of developing a wound complication, with the goal of lessening the associated morbidity and economic burden.

Spinal Implants can be Retained in Patients with Deep Spine Infection: A Cohort Study

Background/Purpose

It is unclear whether implant removal is necessary when deep spine infection of spinal instrumentation occurs. This study compares mortality, relapse, and reoperation rates between such patients with and without removal of spine implants.

Methods

A total of 20 patients were retrospectively reviewed. Baseline characteristics of the implant removal and nonremoval groups were compared. Outcome measures between groups were compared using multivariable logistic regression and predictors of each outcome identified.

Results

There were no significant differences in mortality, relapse, or reoperation rates between groups. Multiple vertebral level involvement was common (85%), and the L4 (30%) and L5 (35%) levels were most commonly involved. The majority of patients had osteomyelitis/spondylodiscitis (50%) and Staphylococcus aureus infections (60%). Thoracic spine infection was associated with relapse (odds ratio = 1.26) and reoperation (odds ratio = 1.101).

Conclusion

Implant removal is not always necessary in cases of deep spine infection as retention of implants is not associated with higher mortality, relapse, or reoperation rates.

Neuromuscular scoliosis complication rates from 2004 to 2015: a report from the Scoliosis Research Society Morbidity and Mortality database

OBJECTIVE Postoperative complications are one of the most significant concerns in surgeries of the spine, especially in higher-risk cases such as neuromuscular scoliosis. Neuromuscular scoliosis is a classification of multiple diseases affecting the neuromotor system or musculature of patients leading to severe degrees of spinal deformation, disability, and comorbidity, all likely contributing to higher rates of postoperative complications. The objective of this study was to evaluate deformity correction of patients with neuromuscular scoliosis over a 12-year period (2004-2015) by looking at changes in postsurgical complications and management. METHODS The authors queried the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database for neuromuscular scoliosis cases from 2004 to 2015. The SRS M&M database is an international database with thousands of self-reported cases by fellowship-trained surgeons. The database has previously been validated, but reorganization in 2008 created less-robust data sets from 2008 to 2011. Consequently, the majority of analysis in this report was performed using cohorts that bookend the 12-year period (2004-2007 and 2012-2015). Of the 312 individual fields recorded per patient, demographic analysis was completed for age, sex, diagnosis, and preoperative curvature. Analysis of complications included infection, bleeding, mortality, respiratory, neurological deficit, and management practices. RESULTS From 2004 to 2015, a total of 29,019 cases of neuromuscular scoliosis were reported with 1385 complications, equating to a 6.3% complication rate when excluding the less-robust data from 2008 to 2011. This study shows a 3.5-fold decrease in overall complication rates from 2004 to 2015. A closer look at complications shows a significant decrease in wound infections (superficial and deep), respiratory complications, and implant-associated complications. The overall complication rate decreased by approximately 10% from 2004-2007 to 2012-2015. CONCLUSIONS This study demonstrates a substantial decrease in complication rates from 2004 to 2015 for patients with neuromuscular scoliosis undergoing spine surgery. Decreases in specific complications, such as surgical site infection, allow us to gauge our progress while observing how trends in management affect outcomes. Further study is needed to validate this report, but these results are encouraging, helping to reinforce efforts toward continual improvement in patient care.

A Retrospective Analysis of Deep Surgical Site Infection Treatment after Instrumented Spinal Fusion with the Use of Supplementary Local Antibiotic Carriers

Background: There is no generally established treatment algorithm for the management of surgical site infection (SSI) and non-union after instrumented spinal surgery. In contrast to infected hip- and knee- arthroplasties, the use of a local gentamicin impregnated carrier in spinal surgery has not been widely reported in literature.

Patients and methods: We studied 48 deep SSI and non-union patients after instrumented spine surgery, treated between 1999 and 2016. The minimum follow-up was 1.5 years. All infections were treated with a treatment-regimen consisting of systemic antibiotics and repetitive surgical debridement, supplemented with local gentamicin releasing carriers.

We analysed the outcome of this treatment regimen with regard to healing of the infection, as well as patient- and surgery-characteristics of failed and successfully treated patients.

Results: 42 of the 48 (87.5%) patients showed successful resolution of the SSI without recurrence with a stable spine at the end of treatment.

36 patients' SSI were treated with debridement, local antibiotics, and retention or eventual restabilization of the instrumentation in case of loosening. 3 patients were treated without local antibiotics because of very mild infection signs during the revision operation. 3 patients were treated with debridement, local antibiotics and removal of instrumentation. One of these patients was restabilized in a second procedure.

Infection persisted or recurred in 6 patients. These patients had a worse physical status with a higher ASA-score. Staphylococcus aureus was the most frequent causative microorganism.

Interpretation: Debridement and retention of the instrumentation, in combination with systemic antibiotics and the addition of local antibiotics provided a successful treatment for SSI and non-union after instrumented spinal fusion.

External validation of a prediction model for surgical site infection after thoracolumbar spine surgery in a Western European cohort

Background

A prediction model for surgical site infection (SSI) after spine surgery was developed in 2014 by Lee et al. This model was developed to compute an individual estimate of the probability of SSI after spine surgery based on the patient’s comorbidity profile and invasiveness of surgery. Before any prediction model can be validly implemented in daily medical practice, it should be externally validated to assess how the prediction model performs in patients sampled independently from the derivation cohort.

Methods

We included 898 consecutive patients who underwent instrumented thoracolumbar spine surgery.

To quantify overall performance using Nagelkerke’s R² statistic, the discriminative ability was quantified as the area under the receiver operating characteristic curve (AUC). We computed the calibration slope of the calibration plot, to judge prediction accuracy.

Results

Sixty patients developed an SSI. The overall performance of the prediction model in our population was poor: Nagelkerke’s R² was 0.01. The AUC was 0.61 (95% confidence interval (CI) 0.54–0.68). The estimated slope of the calibration plot was 0.52.

Conclusions

The previously published prediction model showed poor performance in our academic external validation cohort. To predict SSI after instrumented thoracolumbar spine surgery for the present population, a better fitting prediction model should be developed.

The use of vacuum-assisted closure in spinal wound infections with or without exposed dura

INTRODUCTION

The treatment of postoperative deep spinal wound infection involves debridement and intravenous antibiotics. Authors have previously reported success in a small series of patients treated with vacuum-assisted closure (VAC) therapy, but its use over exposed dura is controversial and the outcome has not been reported in large series.

PURPOSE

To review the outcomes following the treatment of postoperative spinal infections with VAC therapy, particularly those with exposed dura.

METHODS

This is a review of prospectively collected data in 42 patients, all of whom had deep postoperative spinal infections. 30 of these patients had exposed dura. All patients had an initial debridement followed by application of VAC Whitefoam (with exposed dura) or grey Granufoam (where no dura was exposed). Pressure was set at 50 mmHg with exposed dura or 125 mmHg where no dura was exposed. All patients underwent a minimum 6 week course of antibiotics. We report on the number of visits to theatre required for dressing changes and debridement and the eventual outcomes.

RESULTS

Five patients required a flap reconstruction. Two patients died before definitive final closure due to other complications (pneumonia and stroke). In all the other patients, their wounds healed fully. A mean of 2.3 infection surgeries were required to eradicate infection and achieve wound closure.

CONCLUSIONS

This is one of the largest studies which confirms the safety and efficacy of VAC dressings in patients with spinal wound infections, even when the dura is exposed. These slides can be retrieved under Electronic Supplementary Material.

Factors associated with extension of the scheduled time for spine surgery

OBJECTIVES

Adherence to scheduled times in surgery is important in hospital management. However, sudden surgical changes or unexpected intraoperative problems may lead to prolongation of operative times. The purpose of this study was to investigate operative times in spinal surgery and to identify causes of delays during surgery.

PATIENTS AND METHODS

A retrospective review of 488 cases of spinal surgery was performed to investigate operations prolonged for >2 h and to identify factors associated with prolongation.

RESULTS

There were 250 cases without a delay, and 144, 64, and 30 with delays of <1 h, 1-2 h, and >2 h, respectively. Delays >2 h were caused by interruptions due to loss of transcranial motor-evoked potential (Tc-MEP) signals in spinal cord monitoring (n = 15), reinsertion due to screw misplacement (n = 5), intraoperative pathology procedures (n = 5), extension of fusion range with instrumentation (n = 3), and complete resection of an intramedullary tumor (n = 2). Surgeries with delays >2 h (n = 30) had greater rates of scheduled surgery for >5 h (40% vs. 23%; P < 0.05), instrumentation use (70% vs. 47%; P < 0.05), reoperation (33% vs. 7%; P < 0.01%), and estimated blood loss (EBL) (1573 vs. 435 ml; P < 0.01), compared to all other surgeries (n = 458). In multivariate logistic regression, reoperation (HR 3.15, 95% CI 1.52-6.55; p < 0.01) and EBL ≥ 1000 ml (HR 3.35, 95% CI 1.56-7.18; p < 0.01) were significantly associated with prolongation of surgery by >2 h.

CONCLUSION

Information suggesting potential prolongation of surgery should be shared with all medical staff. Reliable surgical techniques and hemostasis may also reduce delays in surgery.

Postoperative Changes in Presepsin Level and Values Predictive of Surgical Site Infection After Spinal Surgery: A Single-Center, Prospective Observational Study

STUDY DESIGN

Single-institutional, prospective observational study.

OBJECTIVE

To elucidate the perioperative kinetics of presepsin (PSEP) in patients undergoing spinal surgery, and to evaluate the possibility of PSEP in the early diagnosis of surgical site infection (SSI).

SUMMARY OF BACKGROUND DATA

Early diagnosis of SSI after spinal surgery is important. Although several biomarkers have been used as early indicators of SSI, the specificity of these markers in SSI diagnosis was not high. PSEP was found as a novel diagnostic marker for bacterial sepsis in 2004. However, its kinetics after spinal surgery and its usefulness in early diagnosis of SSI have never been evaluated.

METHODS

A total of 118 patients who underwent elective spinal surgery were enrolled. PSEP was measured before, immediately after, 1 day after, and 1 week after surgery. In patients without postoperative infection, perioperative kinetics of PSEP were analyzed. PSEP levels in patients with postoperative infection were also recorded separately, and their utility in SSI diagnosis was evaluated.

RESULTS

In the 115 patients without postoperative infection, the median PSEP value was 126, 171, 194, and 147 pg/mL before, immediately after, 1 day after, and 1 week after surgery, respectively. Compared with the preoperative value, PSEP was significantly higher immediately after surgery and the next day, and return to the preoperative level 1 week after surgery. The estimated reference value for 95 percentile in patients without postoperative infection was 297 pg/mL 1 week after surgery. In three patients with postoperative infection, higher levels (>300 pg/mL) were observed 1 week after surgery.

CONCLUSION

In patients after spinal surgery without infectious complications, blood levels of PSEP may immediately increase and return to preoperative levels 1 week after surgery. The PSEP value of 300 pg/mL 1 week after surgery might be used as a novel indicator for suspected SSI.

LEVEL OF EVIDENCE

4.

Methicillin-Resistant Staphylococcus aureus Nasal Swab and Suction Drain Tip Cultures in 4573 Spinal Surgeries: Efficacy in Management of Surgical Site Infections

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

To assess the diagnostic value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab and suction drain tip cultures.

SUMMARY OF BACKGROUND DATA

The prognostic value of MRSA nasal swab and suction drain tip cultures has not been firmly established in spinal surgery.

METHODS

This study retrospectively included 4573 consecutive patients who underwent spinal surgery between January 2008 and December 2014. Patients diagnosed with infectious disease were excluded. Prophylactic antibiotics were administered intraoperatively and postoperatively for 48 hours. MRSA nasal swab cultures were taken from all patients before surgery. Drains were removed when the volume of postoperative fluid drainage was less than 50 mL in the preceding 24 hours and cultures were made. Surgical site infection (SSI) was defined according to Centers for Disease Control and Prevention criteria.

RESULTS

SSI was identified in 94 cases (2.1%) and bacteria were isolated in 87 cases (92.6%). Positive MRSA nasal swab cultures were identified in 49 cases (1.1%). There was no significant difference in the SSI positivity rate between the MRSA nasal swab culture (+) and (-) groups. Positive drain tip cultures were found in 382 cases (8.4%), 28 of which developed SSI. There was a significant difference in the SSI positivity rate between the drain tip culture (+) and (-) groups. The sensitivity of drain tip culture was 29.8% and the specificity was 92.1%. In 16 of the 28 patients in the SSI (+) group with positive drain cultures, the same bacteria were isolated from the surgical site, giving a bacteria matching rate of 57.1%.

CONCLUSION

MRSA nasal swab and drain tip cultures were not useful for predicting SSI. However, drain tip culture had a high positivity rate in the SSI group and the coincidence rate for the causative pathogen was relatively high.

LEVEL OF EVIDENCE

4.

[Infections of the spine : Therapeutic strategies]

Spinal infections are relatively rare entities but the incidence is significantly increasing due to the rapidly growing numbers of interventions on the spine. Primary infections of intervertebral discs (spondylodiscitis) and vertebral bodies (spondylitis) are distinguished from secondary postinterventional infections. Treatment relies primarily on either conservative or surgical management. In the absence of indications for surgery, a conservative approach is indicated when the patient is neurologically intact and the bony destruction is minimal. Conservative therapeutic options are based on the microbiological diagnosis and use of antibiotics, immobilization, analgesics and orthotics. Indications for a surgical intervention are the presence of neurological deficits, intraspinal abscesses, extensive osseous destruction and failure of conservative management. Surgical therapy focusses on the decompression of neural structures, debridement and eradication of the focus of infection, pathogen identification, correction of the deformity and restoration of a physiological spinal profile. Following a postoperative infection a timely diagnosis including assessment of the extent of infection is crucial. In the case of a purely superficial infection, antibiotic prophylaxis and close monitoring is indicated. If findings are pronounced surgical revision, debridement together with antibiotic therapy and if necessary vacuum-assisted closure as well as revision ranging from exchange of implants to complete removal of osteosynthetic material are required. Spinal infections are severe conditions frequently with residual long-term sequelae, whether the patients are managed conservatively or surgically.

Risk Factors for Postoperative Infections After Single-Level Lumbar Fusion Surgery

STUDY DESIGN

Retrospective multivariate analysis of a prospectively collected, multicenter database.

OBJECTIVE

To identify patient characteristics and perioperative risk factors associated with postoperative infectious complications after single-level lumbar fusion (SLLF) surgery.

SUMMARY OF BACKGROUND DATA

Postoperative infection is a known complication after lumbar fusion. Risk factors for infectious complications after lumbar fusion have not been investigated using select set of SLLF procedures.

METHODS

Patients who underwent SLLF between 2006 and 2011 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariate logistic regression analyses were performed to identify pre- and intraoperative risk factors associated with postoperative infection.

RESULTS

A total of 3353 patients were analyzed in this study. Overall, 173 (5.2%) patients experienced a postoperative infection, including 86 (2.6%) surgical site infections (SSIs) and 111 (3.3%) non-SSI infectious complications (pneumonia, urinary tract infection, sepsis/septic shock). Twenty-four (0.7%) patients experienced both SSI and non-SSI infectious complications. Postoperative SSI were associated with obesity (odds ratio [OR], 1.628; 95% confidence interval [CI], 1.042-2.544), American Society of Anesthesiologists class more than 2 (OR, 2.078; 95% CI, 1.309-3.299), and operative time more than 6 hours (OR, 2.573; 95% CI, 1.310-5.056). Risk factors for non-SSI infectious complications included age (60-69 yr; OR, 3.279; 95% CI, 1.541-6.980; and ≥70 yr; OR, 3.348; 95% CI, 1.519-7.378), female sex (OR, 1.791; 95% CI, 1.183-2.711), creatinine more than 1.5 mg/dL (OR, 2.400; 95% CI, 1.138-5.062), American Society of Anesthesiologists class more than 2 (OR, 1.835; 95% CI, 1.177-2.860), and operative time more than 6 hours (OR, 3.563; 95% CI, 2.082-6.097).

CONCLUSION

Across a wide study population, we identified that obesity, advanced American Society of Anesthesiologists classification, and longer operative time were predictive of postoperative SSI. We also demonstrated that increased age, female sex, serum creatinine more than 1.5 mg/dL, and prolonged operative duration are associated with non-SSI infectious complications after SLLF. Continued efforts to elucidate and optimize perioperative risk factors are warranted to improve outcomes in patients requiring spinal fusion.

LEVEL OF EVIDENCE

3.

Use of intrawound vancomycin powder against postoperative infection after spine surgery

Local application of vancomycin has recently become widely used in spine surgery. However, local application is not included in the indication and has not been approved by the US Food and Drug Administration (FDA). Thus, we searched for reports with "intra wound-vancomycin" and "SSI" as keywords in the MEDLINE database, and investigated the efficacy, problems with use, and future prospects based on these reports. Intrawound vancomycin was described as effective in most of the reports, but was found to have no effect or to aggravate the condition in some reports. A toxic effect on osteoblasts due to a high local concentration was described in some reports, whereas local application was found to be safe in other studies. The amount of vancomycin used and the administration method varied among the reports. Overall, the results suggest that intrawound vancomycin is clinically effective, but this has yet to be established in a randomized controlled trial. There is a need to identify cases that should be selected for this treatment and to investigate the dose and optimum concentration of vancomycin for clinical use.

Surgical site infection after transoral versus posterior approach for atlantoaxial fusion: a matched-cohort study

OBJECTIVE

In the past, spine surgeons have avoided the transoral approach to the atlantoaxial segment because of concerns for unacceptable patient morbidity. The objective of this study was to measure 30-day postoperative complications, especially surgical site infection (SSI), after transoral versus posterior approach to atlantoaxial fusion.

METHODS

The source population was provided by the American College of Surgeons National Surgical Quality Improvement Program database, which was queried for all patients who underwent atlantoaxial fusion for degenerative/spondylotic disease and/or trauma between 2005 and 2014. To eliminate bias from unequal sample sizes, patients who underwent the transoral approach were matched with patients who underwent the posterior approach (generally 1:5 ratio) based on age ± 5 years and modified frailty index score (a measure of preoperative comorbidity burden). Because of rare SSI incidence, adjusted odds ratios (ORadj) of SSI were calculated using penalized maximum likelihood estimation.

RESULTS

A total of 318 patients were included in the study. There were no statistically significant differences between the transoral cohort (n = 56) and the posterior cohort (n = 262) in terms of 30-day postoperative individual complications, including SSI (1.79% vs 1.91%; p = 0.951) and composite complications (10.71% vs 6.87%; p = 0.323). Controlling for sex and smoking, the odds of SSI in the transoral approach were almost equal to the odds in the posterior approach (ORadj 1.17; p = 0.866). While the unplanned reoperation rate of 5.36% after transoral surgery was higher than the 1.53% rate after posterior surgery, the difference approached, but did not reach, statistical significance (p = 0.076).

CONCLUSIONS

Transoral versus posterior surgery for atlantoaxial fusion did not differ in 30-day unexpected outcomes. Therefore, spinal pathology, rather than concern for postoperative complications, should adjudicate the technical approach to the atlantoaxial segment.

Deep Surgical Site Infections Following Pediatric Cervical Spine Surgery

OF BACKGROUND DATA

This is the first reported series looking specifically at factors associated with deep surgical site infections (SSI) following pediatric cervical spine surgery.

OBJECTIVE

To identify risk factors present in pediatric patients who are at risk for SSI following cervical spine surgery.

DESIGN

Level of evidence: level IV-retrospective case series.

INTRODUCTION

To date there are no studies regarding SSI in pediatric cervical spine surgery and thus no benchmark data or risk factors have been identified.

METHODS

Patients with acute deep SSIs occurring within 90 days of the index operation were identified. Patient and surgical characteristics were analyzed for possible predictors of SSI outcome using penalized likelihood logistic regression analysis. Characteristics analyzed included: age, diagnosis, comorbidity, levels fused, approach, implants used, allograft, halo, body mass index, revision, antibiotic dosing, and occipital plating.

RESULTS

A total of 112 patients were included in the study at a mean age of 12.5 years (2 to 18 y). Comorbidities were present in 51 (46%) patients, 15 patients had a documented connective tissue disorder (CTD). The mean number of levels fused was 3.7 (2 to 7) and mean number of screws was 4.4 (2 to 11). Allograft was used alone in 48 patients, occipital plating in 28 patients, and a halo in 39 patients. Deep SSI occurred in 3 patients: two of which had a CTD (1 Trisomy 21, 1 Ehlers-Danlos) and 1 patient with postradiation cervical kyphosis. All were gram-positive infections requiring return to operating room with prolonged IV antibiotics. All patients recovered and fused with spinal implant retention. The incidence of deep SSI was 2.7%. It was determined that a CTD was the only significant predictor of SSI. Subjects with a CTD had 12 times the odds of SSI [odds ratio=12 (1.5, 137.0); P=0.02].

CONCLUSIONS

In our series of pediatric patients the incidence of a deep SSI was 2.7%. The only predictor of SSI was the presence of a CTD.

Efficacy of Target Drug Delivery and Dead Space Reduction Using Antibiotic-loaded Bone Cement for the Treatment of Complex Spinal Infection

STUDY DESIGN

A retrospective study.

OBJECTIVES

We have treated complex cases of surgical site infection (SSI) successfully using antibiotic-loaded bone cement to avoid the need for implant removal. In the present study, we describe a new treatment option for SSI.

SUMMARY OF BACKGROUND DATA

Although there are several treatment options for SSI after spinal surgery involving instrumentation, several types of problems may arise and are difficult to cure.

MATERIALS AND METHODS

Eleven patients with SSI after undergoing spinal surgery involving instrumentation were studied. All had been refractory to conventional treatments, including intravenous antibiotic administration and conventional debridement and irrigation. Antibiotic-loaded bone cement was placed on and around the instrumentation to cover them and to occupy the surrounding dead space. Two general types of antibiotics were loaded into the polymethylmethacrylate bone cement. The recipes for the mixture were changed depending on the bacterial cultures. Sensitive antibiotics were administered generally for 2-6 weeks until the C-reactive protein level was normalized.

RESULTS

All patients were treated successfully using antibiotic-loaded bone cement. Only 1 patient needed a repeat of this procedure to treat an infection. Antibiotic-loaded bone cement was placed in situ in all patients during the follow-up period and there were no significant adverse events.

CONCLUSIONS

Antibiotic-loaded bone cement treatment reduces the dead space and achieves the targeted drug delivery simultaneously. Treatment using antibiotic-loaded bone cement is an effective treatment option for complex spinal SSI.

Postoperative Spine Dressing Changes Are Unnecessary

INTRODUCTION

There is minimal literature regarding when dressing changes should be performed. We present the dressing change protocol adopted by our institution. The purpose of this study was to provide an update of our experience with this dressing change protocol over a 15-year period.

METHODS

Effective January 2005, we implemented our universal protocol of no dressing changes for five days after surgery. Reviewing a health system administrative database, all spine surgery cases involving instrumentation performed at our institution were captured. Surgical site infection (SSI) cases: superficial, deep, and organ space as defined by the Centers for Disease Control and Prevention (CDC), were identified by reviewing an infection control database. Fisher exact test was used to compare SSI rates in all instrumented fusion cases from January 1999 to December 2004 (prior to implementation of the dressing change protocol) to those from January 2005 to December 2013 (after the protocol was initiated).

RESULTS

A total of 8,631 instrumented spine fusions were performed at a single institution from 1999 to 2013. Overall, after instituting our universal no-dressing-change protocol, SSI rates for all cervical, thoracic, and lumbar instrumented cases combined decreased from 3.9% (97/2473) to 0.93% (57/6158) (p < .0001). The reduction in SSI rates was most significant for posterior cervical and posterior lumbar surgeries. After our dressing change protocol was implemented, we saw an improvement in SSI rates for posterior cervical instrumented cases from 3.2% (6/186) to 0.50% (4/815) (p = .0041). Posterior lumbar instrumented fusion SSI rates dropped from 5.5% (65/1179) to 1.1% (32/2890) (p < .0001).

CONCLUSION

Dressing changes in the immediate postoperative period are not necessary. Applying a sterile dressing in the operating room may serve as a barrier to nosocomial pathogens during hospitalization. Our data suggest this dressing change protocol may lead to reduced SSI risk. Leaving the original postoperative surgical dressing intact is safe, simple, and cost-effective.

Effect of Intra-wound Vancomycin for Spinal Surgery: A Systematic Review and Meta-analysis

Intra-site prophylactic vancomycin in spine surgery is an effective method of decreasing the incidence of postsurgical wound infection. However, there are differences in the prophylactic programs used for various spinal surgeries. Thus, this systematic review and meta-analysis aimed to evaluate the effectiveness of using intra-wound vancomycin during spinal surgery and to explore the effects of dose-dependence and the method of administration in a subgroup analysis. A total of 628 citations or studies were searched in PubMed, Ovid, Web of Science, and Google Scholar that were published before August 2016 with the terms "local vancomycin", "intra-wound vancomycin", "intraoperative vancomycin", "intra-site vancomycin", "topical vancomycin", "spine surgery", and "spinal surgery". Finally, 19 retrospective cohort studies and one prospective case study were eligible for inclusion in the systematic review and meta-analysis. The odds of developing postsurgical wound infection without prophylactic local vancomycin use were 2.83-fold higher than the odds of experiencing wound infection with the use of intra-wound vancomycin (95% confidence interval, 2.03-3.95; P = 0.083; I2 = 32.2%). The subgroup analysis including the dosage and the method of administration, revealed different results compared to previous research. The value of I2 in the 1-g group was 27.2%, which was much lower than in the 2-g group (I2 = 57.6%). At the same time, the value of I2 was 0.0% (P = 0.792, OR = 2.70) when vancomycin powder was directly sprinkled into all layers of the wound. However, there is high heterogenicity (I2 = 60.0%, P = 0.007, OR = 2.83) when vancomycin powder is not exposed to the bone graft and instrumentation. There are differences found with the method of local application of vancomycin for reducing postoperative wounds and further studies are necessary, including investigations focusing on the dose-dependent effects during spinal or the topical pharmacokinetic and other orthopaedic surgeries.

Variation of C-Reactive Protein and White Blood Cell Counts in Spinal Operation: Primary Fusion Surgery Versus Revision Fusion Surgery

Objective

Serum C-reactive protein (CRP) concentrations and white blood cell (WBC) count are commonly used to identify postoperative wound infections. We investigated whether changes in serum CRP levels and WBC counts actually differed between patients undergoing revision spinal fusion surgery and those undergoing a primary fusion.

Methods

Patients who underwent posterolateral fusion (PLF) surgery at Pusan National University Yangsan Hospital between October 2013 and April 2015 were considered for this study. Sixty-seven patients with primary lumbar PLF (pPLF) and 21 with revision PLF (rPLF) were enrolled. A retrospective assessment of preoperative and postoperative CRP levels and WBC count was undertaken. Also, we gathered peak CRP day, and CRP normalization days. Comorbidity data were also obtained to evaluate any effects on the course of CRP and WBC count postoperatively.

Results

CRP levels peaked at 3 days after surgery. The maximum CRP values recorded for each group: 4.17 (standard deviation [SD], 4.18) mg/dL and 4.88 (SD, 3.03) mg/dL for pPLF and rPLF. This difference was not statistically significant (p=0.24). A rapid fall in CRP within 5–9 days was observed for both groups.

Conclusion

Out of our expectation, changes in CRP levels after spinal fusion surgery follow the same course regardless of whether it is a revision operation or not. Because of this result, both the primary PLF surgery and revision PLF surgery should be monitored using CRP in the similar way and the antibiotic administration should be determined.

Surgical site infections following instrumented stabilization of the spine

Background

Implant-associated infections are still a feared complication in the field of orthopedics. Bacteria attach to the implant surface and form so-called biofilm colonies that are often difficult to diagnose and treat. Since the majority of studies focus on prosthetic joint infections (PJIs) of the hip and knee, current treatment options (eg, antibiotic prophylaxis) of implant-associated infections have mostly been adapted according to these results.

Objective

The aim of this study was to evaluate patients with surgical site infections following instrumented stabilization of the spine with regard to detected bacteria species and the course of the disease.

Patients and methods

We performed a retrospective single-center analysis of implant-associated infections of the spine from 2010 to 2014. A total of 138 patients were included in the study. The following parameters were evaluated: C-reactive protein serum concentration, microbiological evaluation of tissue samples, the time course of the disease, indication for instrumented stabilization of the spine, localization of the infection, and the number of revision surgeries required until cessation of symptoms.

Results

Coagulase-negative Staphylococcus spp. were most commonly detected (n=69, 50%), followed by fecal bacteria (n=46, 33.3%). In 23.2% of cases, no bacteria were detected despite clinical suspicion of an infection. Most patients suffered from degenerative spine disorders (44.9%), followed by spinal fractures (23.9%), non-degenerative scoliosis (20.3%), and spinal tumors (10.1%). Surgical site infections occurred predominantly within 3 months (64.5%), late infections after 2 years were rare (4.3%), in particular when compared with PJIs. Most cases were successfully treated after 1 revision surgery (60.9%), but there were significant differences between bacteria species. Fecal bacteria were more difficult to treat and often required more than 1 revision surgery.

Conclusion

In summary, we were able to demonstrate significant differences between spinal implant-associated infections and PJIs. These aspects should be considered early on in the treatment of surgical site infections following instrumented stabilization of the spine.

Rate of Complications Following Spinal Cord Stimulation Paddle Electrode Removal

OBJECTIVE

Spinal cord stimulation (SCS) is a safe, reversible surgical treatment for complex regional pain syndrome and failed back surgery syndrome refractory to conventional medical management. Paddle electrodes are routinely used for the permanent implant because of the reduced risk of migration, lower energy requirements, and expanded coverage options. The risks associated with paddle lead removal are not well defined in the literature.

METHODS

We retrospectively reviewed the outcomes of all patients at the Cleveland Clinic who underwent removal of SCS paddle electrodes between 2009 and 2016.

RESULTS

We identified 68 patients during this interval who had a paddle electrode removed. The most common reason for removal was loss of coverage or effect (75%), followed by infection (13.24%), and the need for magnetic resonance imaging for diagnostic purposes (8.82%). Postoperative complications occurred in eight patients (11.75%), two of which were classified as major (2.94%). One of these patients developed a postoperative cerebrospinal fluid leak, and another suffered a large suprafascial hematoma. Both patients underwent reoperation. Minor complications were reported in six patients (8.82%) and included wound dehiscence, infection, and prolonged ileus in one case. On average, patients who developed complications lost 20 mL more blood during surgery than those who did not develop complications (p = 0.006).

CONCLUSION

One of the benefits of SCS therapy is the reversibility of the procedure. However, removal is not without some risk though the overall risk of minor or major complication is low. Patients who are considering removal should be counseled appropriately. Prophylactic removal is not recommended. However, when removal is needed, surgeons and pain specialists must be familiar with these complications and their management.

Incidence, Impact, and Risk Factors for 30-Day Wound Complications Following Elective Adult Spinal Deformity Surgery

STUDY DESIGN

Case-control study.

OBJECTIVE

To determine the incidence, impact, and risk factors for wound complications within 30 days following elective adult spinal deformity surgery.

METHODS

Current Procedural Terminology and International Classification of Diseases, Ninth Edition, diagnosis codes were used to query the database for adults who underwent spinal deformity surgery from 2010 to 2014. Patients were separated into groups of those with and without wound complications. Univariate analysis and multivariate logistic regression were used to analyze the influence of patient factors, operative variables, and clinical characteristics on the incidence of postoperative wound complication. This study was qualified as exempt by the Mount Sinai Hospital Institutional Review Board.

RESULTS

A total of 5803 patients met the criteria for this study. Wound complications occurred in 140 patients (2.4%) and were significantly associated with other adverse outcomes, including higher rates of unplanned reoperation (P < .0001) and prolonged length of stay (P < .0001). Regardless of fusion length, wound complication rates were higher with a posterior approach (short = 2.7%; long = 3.7%) than an anterior one (short = 2.2%; long = 2.7). According to the multivariate analysis, posterior fusion (odds ratio [OR] = 1.8; P = .010), obese class II (OR = 1.7; P = .046), obese class III (OR = 2.8; P < .0001), preoperative blood transfusion (OR = 6.1; P = .021), American Society of Anesthesiologists class ≥3 (OR = 1.7; P = .009), and operative time >4 hours (OR = 1.8; P = .006) were statistically significant risk factors for wound complications.

CONCLUSION

The 30-day incidence of wound complication in adult spinal deformity surgery is 2.4%. The risk factors for wound complication are multifactorial. This data should provide a step toward developing quality improvement measures aimed at reducing complications in high-risk adults.

Polymicrobial and Monomicrobial Infections after Spinal Surgery: A Retrospective Study to Determine which Infection is more Severe

Study Design

A retrospective clinical review.

Purpose

To investigate the difference in clinical manifestations and severity between polymicrobial and monomicrobial infections after spinal surgery.

Overview of Literature

Surgical site infections (SSIs) after spinal surgery are a major diagnostic and therapeutic challenge for spinal surgeons. Polymicrobial infections after spinal surgery seem to result in poorer outcomes than monomicrobial infections because of complementary resistance to antibiotics. However, comparison of the clinical manifestations and severity between polymicrobial and monomicrobial infections are limited.

Methods

Sixty-seven patients with SSIs after spinal surgery were studied: 20 patients with polymicrobial infections and 47 with monomicrobial infections. Pathogenic bacteria identified were counted and classified. Age, sex, and body mass index were compared between the two groups to identify homogeneity. The groups were compared for clinical manifestations by surgical site, postoperative time to infection, infection site, incisional drainage, incisional swelling, incisional pain, neurological signs, temperature, white blood cell count, and the percentage of neutrophils. Finally, the groups were compared for severity by hospital stay, number of rehospitalizations, number of debridements, duration of antibiotics administration, number of antibiotics administered, and implant removal.

Results

Polymicrobial infections comprised 29.9% of SSIs after spinal surgery, and most polymicrobial infections (70.0%) were caused by two species of bacteria only. There was no difference between the groups in terms of clinical manifestations and severity. In total, 96 bacterial strains were isolated from the spinal wounds: 60 strains were gram-positive and 36 were gram-negative pathogenic bacteria. Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Enterobacter cloacae were cultured in order of the frequency of appearance.

Conclusions

Most polymicrobial infections were caused by two bacterial species after spinal surgery. There was no difference in clinical manifestations or severity between polymicrobial and monomicrobial infections.

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

BACKGROUND

There are no previous studies evaluating risk factors for surgical site infections (SSIs) and the effectiveness of prophylactic antibiotic treatment (PAT), specifically for patients operated on for lumbar disc herniation.

METHOD

This observational multicentre study comprises a cohort of 1,772 consecutive patients operated on for lumbar disc herniation without laminectomy or fusion at 23 different surgical units in Norway. The patients were interviewed about SSIs according to a standardised questionnaire at 3 months' follow-up.

RESULTS

Three months after surgery, 2.3% of the patients had an SSI. Only no PAT (OR = 5.3, 95% CI = 2.2-12.7, p< 0.001) and longer duration of surgery than the mean time (68 min) (OR = 2.8, 95% CI = 1.2-6.6, p = 0.02) were identified as independent risk factors for SSI. Numbers needed to have PAT to avoid one SSI was 43.

CONCLUSIONS

In summary, this study clearly lends support to the use of PAT in surgery for lumbar disc herniation. Senior surgeons assisting inexperienced colleagues to avoid prolonged duration of surgery could also reduce the occurrence of SSI.

Deep spinal infection in instrumented spinal surgery: diagnostic factors and therapy

AIM

Postoperative surgical site infections (SSI) are complication of spinal surgery. These complications may lead to a poor outcome with neurological deficits, spinal deformity and chronic pain. The purpose of this study is to explore the statistical value of diagnostic parameters and the proper therapy.

METHOD

We retrospectively reviewed 550 patients who underwent spinal instrumentation at our department from January 2011 to December 2015. The SSI was present in 16 patients out of 550 operated. Diagnostic criteria of SSI were the positivity of the surgical wound swab or blood culture, the clinical findings, positivity of laboratory tests and radiological elements. All patients had peri-operative antibiotic prophylaxis. Diagnostic laboratory findings were compared with a homogeneous control group of 16 patients and analyzed by univariate statistical analysis with Chi-square test for the discrete variables. P<0,05 was considered statistically significant.

RESULTS

Matching the SSI patients with a group of control, fever was not statistically significant for diagnosis as number of leukocytes, neutrophils and lymphocytes. On the contrary values of ESR and CRP were statistically significant with p <0, 01. The hardware was removed only in 3 patients (18%) out of 16 SSI patients.

CONCLUSION

In this study the statistically significant parameters to diagnose SSI are ESR and CRP values. The leucocytes count, number of lymphocytes and presence of fever integrates the data of ESR and CRP with no statistical significance. Most patients with SSI reach clinical healing with favorable outcome by means of target antibiotic therapy without hardware removal.

Pedicle Screw Fluid Sign: An Indication on Magnetic Resonance Imaging of a Deep Infection After Posterior Spinal Instrumentation

STUDY DESIGN

A single-center case-referent study.

OBJECTIVE

To assess whether the "pedicle screw (PS) fluid sign" on magnetic resonance imaging (MRI) can be used to diagnose deep surgical site infection (SSI) after posterior spinal instrumentation (PSI).

SUMMARY OF BACKGROUND DATA

MRI is a useful tool for the early diagnosis of a deep SSI. However, the diagnosis is frequently difficult with feverish patients with clear wounds after PSI because of artifacts from the metallic implants. There are no reports on MRI findings that are specific to a deep SSI after PSI. We found that fluid collection outside the head of the PS on an axial MRI scan (PS fluid sign) strongly suggested the possibility of an abscess.

METHODS

The SSI group comprised 17 patients with a deep SSI after posterior lumbar spinal instrumentation who had undergone an MRI examination at the onset of the SSI. The non-SSI group comprised 64 patients who had undergone posterior lumbar spinal instrumentation who did not develop an SSI and had an MRI examination within 4 weeks after surgery. The frequency of a positive PS fluid sign was compared between both groups.

RESULTS

The PS fluid sign had a sensitivity of 88.2%, specificity of 89.1%, positive predictive value of 68.1%, and negative predictive value of 96.6%. The 2 patients with a false-negative PS fluid sign in the SSI group had an infection at the disk into which the interbody cage had been inserted. Three of the 7 patients with a false-positive PS fluid sign in the non-SSI group had a dural tear during surgery.

CONCLUSIONS

The PS fluid sign is a valuable tool for the early diagnosis of a deep SSI. The PS fluid sign is especially useful for diagnosing a deep SSI in difficult cases, such as feverish patients without wound discharge.

Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool

OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.

Surgical Site Infections Caused by Methicillin-resistant Staphylococcus epidermidis After Spinal Instrumentation Surgery

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To determine relevant demographics, clinical presentations, and outcomes of surgical site infections (SSIs) after spinal instrumentation (SI) surgery caused by methicillin-resistant Staphylococcus epidermidis (MRSE).

SUMMARY OF BACKGROUND DATA

This is the first study looking specifically at MRSE-related SSIs after SI surgery.

METHODS

We performed a retrospective review of patients with MRSE-related SSIs from 665 consecutive cases of SI surgery performed between 2007 and 2014 at our institution.

RESULTS

During the study period, SSIs occurred in 21 patients. MRSE was isolated from cultures obtained from surgical wounds in nine of the 21 patients (43%). There were four males and five females with a mean age of 63.9 ± 15.1 years. Six patients presented with inflammatory signs, such as wound drainage, pyrexia, erythema, and elevated C-reactive protein. Three patients did not have signs of infection, but had early implant failure, and were diagnosed by positive cultures collected at the time of revision surgery. The mean time from index surgery to the diagnosis of infection was 23.6 days (range, 7-88 days). In one patient, the implant was removed before antibiotic treatment was administered because of implant failure. Eight patients were managed with antibiotics and implant retention. During the follow-up period, MRSE-related SSIs in seven of the eight patients were resolved with implant retention and antibiotics without the need for further surgical intervention. One patient did not complete the antibiotic course because of side effects, and implant removal was required to control the infection.

CONCLUSION

Early detection, surgical debridement, and administration of appropriate antibiotics for a suitable duration enabled infection control without the need for implant removal in the treatment of MRSE-related SSI after SI surgery.

LEVEL OF EVIDENCE

4.