Risk factors for surgical site infection in spinal surgery
ABSTRACT The objective of this study was to identify specific independent risk factors for surgical site infections (SSIs) occurring after laminectomy or spinal fusion.
The authors performed a retrospective case-control study of data obtained in patients between 1996 and 1999 who had undergone laminectomy and/or spinal fusion. Forty-one patients with SSI or meningitis were identified, and data were compared with those acquired in 178 uninfected control patients. Risk factors for SSI were determined using univariate analyses and multivariate logistic regression. The spinal surgery-related SSI rate (incisional and organ space) during the 4-year study period was 2.8%. Independent risk factors for SSI identified by multivariate analysis were postoperative incontinence (odds ratio [OR] 8.2, 95% confidence interval [CI] 2.9-22.8), posterior approach (OR 8.2, 95% CI 2-33.5), procedure for tumor resection (OR 6.2, 95% CI 1.7-22.3), and morbid obesity (OR 5.2, 95% CI 1.9-14.2). In patients with SSI the postoperative hospital length of stay was significantly longer than that in uninfected patients (median 6 and 3 days, respectively; p < 0.001) and were readmitted to the hospital for a median additional 6 days for treatment of their infection. Repeated surgery due to the infection was required in the majority (73%) of infected patients.
Postoperative incontinence, posterior approach, surgery for tumor resection, and morbid obesity were independent risk factors predictive of SSI following spinal surgery. Interventions to reduce the risk for these potentially devastating infections need to be developed.
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ABSTRACT: There is very little evidence to guide treatment of patients with spinal surgical site infection (SSI) who require irrigation and debridement (I&D) in deciding need for single or multiple I&Ds or more complex wound management such as vacuum-assisted closure dressing or soft-tissue flaps. The purpose of this study was to build a predictive model that stratifies patients with spinal SSI, allowing us to determine which patients will need single versus multiple I&D. The model will be validated and will serve as evidence to support a scoring system to guide treatment. A consecutive series of 128 patients from a tertiary spine center (collected from 1999 to 2005) who required I&D for spinal SSI were studied based on data from a prospectively collected outcomes database. More than 30 variables were identified by extensive literature review as possible risk factors for SSI and tested as possible predictors of risk for multiple I&D. Logistic regression was conducted to assess each variable's predictability by a "bootstrap" statistical method. A prediction model was built in which single or multiple I&D was treated as the "response" and risk factors as "predictors." Next, a second series of 34 different patients meeting the same criteria as the first population were studied. External validation of the predictive model was performed by applying the model to the second data set, and predicted probabilities were generated for each patient. Receiver operating characteristic curves were constructed, and the area under the curve (AUC) was calculated. Twenty-four of one hundred twenty-eight patients with spinal SSI required multiple I&D. Six predictors: anatomical location, medical comorbidities, specific microbiology of the SSI, the presence of distant site infection (ie, urinary tract infection or bacteremia), the presence of instrumentation, and the bone graft type proved to be the most reliable predictors of need for multiple I&D. Internal validation of the predictive model yielded an AUC of 0.84. External validation analysis yielded AUC of 0.70 and 95% confidence interval of 0.51 to 0.89. By setting a probability cutoff of .24, the negative predictive value (NPV) for multiple I&D was 0.77 and positive predictive value (PPV) was 0.57. A probability cutoff of .53 yielded a PPV of 0.85 and NPV of 0.46. Patients with positive methicillin-resistant Staphylococcus aureus culture or those with distant site infection such as bacteremia were strong predictors of need for multiple I&D. Presence of instrumentation, location of surgery in the posterior lumbar spine, and use of nonautograft bone graft material predicted multiple I&D. Diabetes also proved to be the most significant medical comorbidity for multiple I&D. The validation of this predictive model revealed excellent PPV and good NPV with appropriately chosen probability cutoff points. This study forms the basis for an evidence-based classification system, the Postoperative Infection Treatment Score for the Spine that stratifies patients who require surgery for SSI, based on specific spine, patient, infection, and surgical factors to assess a low, indeterminate, and high risk for the need for multiple I&D.The spine journal: official journal of the North American Spine Society 03/2012; 12(3):218-30. DOI:10.1016/j.spinee.2012.02.004 · 2.80 Impact Factor
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ABSTRACT: Diabetes mellitus is thought to be a risk factor for surgical site infection. There have been no reports about the infection rate in diabetic patients who have undergone posterior spinal instrumented fusion. We present a retrospective analysis of infection rates after posterior spinal instrumented fusion in diabetic and non-diabetic patients. Of 337 patients who underwent posterior spinal instrumented fusion between 1995 and 1997, 39 were diabetic. Plasma glucose concentration, body mass index, type of instrument, operation time, blood loss, hospital stay and complications were recorded. The pathogenic organism and treatments for infection were also described. The rate of wound infection in diabetic patients was 10.3% compared with 0.7% in non-diabetic patients (p = 0.003). Body mass index and preoperative blood sugar were also significantly different between the two groups (p = 0.02, p < 0.001). Patients with a diabetic history or preoperative hyperglycemia had a higher infection rate after posterior spinal instrumented fusion when compared with non-diabetic patients.Chang Gung medical journal 29(5):480-5.
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ABSTRACT: Surgical site infection (SSI) is the commonest hospital acquired infection that occurs in early postoperative period in surgical patients and accounts for 38% of infections in surgical patients and 31.1% of all infections in trauma patients. Ifs frequency increase parallels increase in number of risk factors. Prevention of peri-operative infection necessitates management directed at optimizing of patient factors like smoking, nutritional factors, immune-suppression, obesity and cardiovascular status. Use of principles like antibiotic prophylaxis, aseptic theatre conditions, respect of soft tissues during operation, local therapy and other modern patient safety practices is mandatory. Antibiotic prophylaxis should be started early pre-operatively at least 30-60 minutes before incision and antibiotic level exceeding minimal inhibitory concentration for infecting organism or before inflation of a tourniquet if applicable to closure of wound. Aiming at short preoperative stay in hospital, and pre-washing of the area concerned before cleaning with antiseptic are also imperative in reducing SSI. Preoperative skin preparation is an important element in prevention of infection, but removes only up to 80% of skin flora. Standard surgical antisepsis is an accepted method and involves scrubbing with antiseptic solutions. Chlorhexidine gluconate compared with povodine iodine showed a prolonged reduction in skin contamination and with less toxicity and skin irritation. Aqueous surgical hand scrubs are equivalent to traditional scrubs with regard to reduction of skin contamination, with higher surgeons protocol compliancy compared to traditional scrubs. The use of laminar flow and ultra-violet light in theatre is associated with decreased rates of postoperative skin infections and contamination. Respect of soft tissues during surgery through decrease in excessive use of diathermy, contusions and excessive tension is advised. Wound closure without tension and no dead space is encouraged. Issues of wound drainage have not been shown to reduce rates of infection. When used, closed suction drainage is better than open drain. SSI is a common complication and it is in the interest of the surgeon and the patient that it is prevented as it can be associated with morbidity, mortality and increased resource utilization. This article will deal with peri-operative management of the orthopaedic patient using evidence based benefits to the current practices available from recent updates, reviews and prospective randomized control trials, and some retrospective studies.