ORIGINAL ARTICLE
Risk Factors for Surgical Site Infection in Patients Undergoing Sacral Nerve Modulation Therapy Taylor Brueseke, MD, Briana Livingston, MD, Hussein Warda, MD, Kathryn Osann, PhD, and Karen Noblett, MD
Objectives: The aim of this study was to identify risk factors for surgical site infection in patients undergoing sacral nerve modulation (SNM) surgery.
Methods: We conducted a retrospective cohort analysis of 290 patients undergoing a total of 669 SNM procedures between 2002 and 2012 by 2 fellowship-trained female pelvic medicine and reconstructive surgery attending physicians at the University of California–Irvine Medical Center. Infection was defined as a charted abnormal examination finding at the implantation site (erythema, induration, purulent discharge) resulting in prescription of antibiotics, hospitalization, or explantation. We extracted information from the medical record regarding possible risk factors for infection including age, body mass index, immunosuppression (diabetes mellitus, chronic steroid use, smoker, chemotherapy), number of procedures per patient, and number of days between stages 1 and 2. In addition, we compared infection rates before and after 2008 when a clinical practice change was made with the implementation of home chlorhexidine washing (CHW) prior to SNM surgery. Results: Thirty infections occurred, 25 of which were managed with oral antibiotics. Nine required intravenous antibiotics, and 11 required removal of the implanted device. Three patients experienced infection on 2 separate occasions. Seventeen infections had culture data available. Nine of the patients who underwent explantation had wound cultures positive for methicillin-resistant Staphylococcus aureus. Thirteen of the 26 patients who developed infection had medical histories significant for immunosuppression. Three patients developed late-onset abscess formation at 234, 257, and 687 days after stage 2, respectively. The median time between the most recent SNM procedure and development of infection was 14 days (range, 6–88 days). Body mass index and immunosuppression were significant predictors of infection, whereas age, parity, indication for procedure, and number of days between stages 1 and 2 were not found to be independent predictors. Three hundred twenty-three procedures were performed prior to and 346 procedures were performed after institution of home CHW. Twentyfour (80%) of the 30 reported infections were prior to CHW, whereas only 6 infections (20%) occurred after this change in practice. Prior to institution of CHW, the infection rate was 7.4%, and after institution of CHW, it was 1.7% (P = 0.002). Of the 83 patients with compliance data available for CHW use, 71 reported using CHW, whereas 12 reported not using CHW. Conclusions: Surgical site infection is a significant risk of SNM surgery, although our infection rate is lower than previously reported. Chlorhexidine washing appears to reduce the risk of infection in this population. Because the majority of infections requiring explantation were methicillin-resistant S. aureus positive, prophylactic treatment for this organism should be considered as an additional strategy to reduce infection. Body mass index and immunosuppression appear to be independent risk factors for infection. Key Words: sacral nerve modulation, risk factors, infection, chlorhexidine gluconate From the Division of Urogynecology, Department of Obstetrics and Gynecology, University of California–Irvine, Orange, CA. Reprints: Karen Noblett, MD, University of California–Irvine, 101 The City Dr S Bldg 56, Suite 800, Orange, CA 92868. E-mail: [email protected]. The authors declare that they have nothing to disclose. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/SPV.0000000000000183
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O
veractive bladder is a prevalent condition that is reported to effect one third of adults older than 40 years.1 Treatment modalities for this condition can be broadly categorized into conservative (including lifestyle changes, pelvic floor physical therapy, or medications) and procedural/surgical. Sacral nerve modulation (SNM) is a minimally invasive procedure that is Food and Drug Administration approved for the treatment of urgency incontinence, urgency-frequency syndrome, nonobstructive urinary retention, and fecal incontinence. Sacral nerve modulation delivers nonpainful, mild electrical pulses to the sacral nerves to modulate the reflexes that influence the bladder, sphincters, and pelvic floor to improve or restore normal voiding and defecatory functions. Device implantation is generally performed in 2 stages as described by Siegel et al.2 The first stage involves percutaneous placement of a quadripolar lead wire adjacent to the S3 nerve root, which is connected to an external pulse generator. A reduction of 50% in symptoms or greater, depending on the indication for implantation, is considered a successful response to therapy and is an indication for implantation of the chronic device. Stage 2 consists of implantation of the implantable pulse generator (IPG) in the upper buttock area. Currently, the only commercially available SNM device is Interstim (Medtronic, Minneapolis, Minn), which has been available in the United States since 1997. Since its introduction, SNM has undergone significant improvements in design and application so that implantation is now a minimally invasive procedure performed under local anesthesia and intravenous sedation. Despite the progress made in advancing this therapy to a minimally invasive procedure, significant adverse events may occur. The rate of surgical site infection has been reported to be between 1% and 23%.3–7 Length of time between stages 1 and 2 has not been shown to be predictive of risk of infection.8 Use of gentamicin-impregnated collagen has been described as a potential method to reduce surgical site infections. In a small study of 8 patients who had a gentamicin-impregnated collagen sheet placed in the subcutaneous pocket at the time of pulse generator implantation, there were no reported infections over a median of 89 days of follow-up.9 Currently, there is a paucity of data to help inform us on best practices in the preoperative and postoperative period to decrease infection rates in SNM procedures. In an effort to reduce surgical site infection, the Centers for Disease Control has recommended home bathing with an antiseptic agent on at least the night prior to and morning of surgery.10 Chlorhexidine gluconate is a broad-spectrum topical antibiotic that disrupts the cell membrane of bacteria, the daily use of which has recently gained national attention for decreasing the rate of multidrug-resistant hospital-acquired bloodstream infections in intensive care unit patients.11,12 Prospective cohort studies with historical controls have shown a decrease in surgical site infection after implementation of home and in-hospital preoperative chlorhexidine wiping13,14 and also in-hospital preoperative wiping alone.15 Retrospective
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studies16 and all-modality inclusive meta-analysis17 have not shown significant reductions in surgical site infection. However, interpretation of the literature surrounding the use of chlorhexidine bathing to reduce surgical site infection is complicated by the diversity of study designs used. Variations include the mechanism of chlorhexidine administration: wiping (chlorhexidine impregnated wipes) versus washes (liquid chlorhexidine packets or bottles that are instructed to be applied to a washcloth and used in a shower) versus baths (liquid chlorhexidine that is to be added to a full-body bath). Additional complexity is encountered regarding the timing, frequency, and setting of chlorhexidine administration: 1-wash versus multiple, in-hospital preoperative application only versus home application with or without in-hospital preoperative application. Studies including home application vary on the number of applications to administer. In 2007, 4 of our patients experienced surgical site infections, 3 of which were from methicillin-resistant Staphylococcus aureus (MRSA). These occurred temporally very close together, and this prompted a change in our practice by instituting a home chlorhexidine wash: once at night the day before surgery and again the morning of surgery. This is the only identifiable practice change that occurred between the time periods before and after 2008 when this practice was implemented. We present a retrospective cohort analysis of 290 patients who underwent 668 SNM surgical procedures. Our purpose was to identify preoperative and postoperative risk factors associated with surgical site infections. In addition, we evaluated the effectiveness of chlorhexidine washing (CHW) to decrease SNM procedure surgical site infection rates.
METHODS After institutional review board approval, we conducted a retrospective cohort analysis of female patients undergoing SNM procedures between 2002 and 2012 by 2 fellowship-trained Female Pelvic Medicine and Reconstructive Surgery. Patients were identified by CPT codes 64581 and 64590. Charts were excluded if there was incomplete follow-up or documentation. We extracted information from the medical record regarding possible risk factors for infection including age, body mass index (BMI), immunocompromised state (diabetes mellitus, chronic steroid use, current smoker, chemotherapy), number of stages 1 and 2 procedures, and number of days between the stage 1 and stage 2 procedures. Information regarding indication for the procedure was also extracted. Standard practice at our institution has been to utilize a staged approach to SNM. We offer office-based peripheral nerve evaluation and operating room–based placement of the lead wire. When stage 1 is performed in the operating room, a tined lead wire is placed adjacent to the S3 nerve root and then tunneled underneath the skin to a pocket created in the subcutaneous tissue of the ipsilateral buttocks where it is joined to an extension wire. The extension wire is then tunneled underneath the skin to an exit site in the contralateral buttocks and connected to an external pulse generator. Non-tined leads were used in office-based peripheral nerve evaluations. Tined leads were used in operating room–based procedures. No fascial or periosteal anchoring was performed during this time period. We administer perioperative intravenous antibiotics and postoperative oral daily antibiotic prophylaxis between stages 1 and 2. Neither this practice nor the antibiotic selection changed during the study period. We used an iodine-based surgical preparation at the time of surgery throughout the study period. Infection was defined as a documented abnormal examination finding at the lead wire exit site, extension wire connector pocket, or IPG insertion site (erythema, induration, purulent © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Sacral Nerve Modulation Therapy
discharge), resulting in prescription of antibiotics, hospitalization, or device removal. Prior to 2008, patients at our institution undergoing SNM surgery did not receive preoperative instructions to perform home CHW. Beginning in 2008, patients were routinely provided with liquid 4% chlorhexidine gluconate and instructed to shower with it the night before surgery and the morning of surgery. They were instructed to liberally apply the solution to a washcloth or mesh sponge and to massage the solution into all areas of external skin. Patients were instructed to leave the chlorhexidine on their skin for 2 minutes and then to rinse with clean water and dry with a clean towel. Data regarding patient compliance with CHW are available from 2011 to 2012 (coinciding with the implementation of an electronic medical record in our preoperative holding area) and were documented by nursing staff in the preoperative holding area the day of surgery. Descriptive data are reported using mean, median, and range. Rates of infection before and after 2008 are compared using Fisher exact test. Univariate and multivariate analyses were performed.
RESULTS We identified 319 patient records, 290 of which met the above criteria and underwent a total of 669 SNM procedures (359 stage 1 and 310 stage 2). Mean age was 65 years (range, 16–90 years). Median BMI was 26.6 kg/m2 (range, 14–49 kg/m2). Median length of time between stage 1 and stage 2 was 14 days. Median follow-up time was 12 months (Table 1). Twenty-six patients (3.8%) developed an infection (4 patients experienced 2 separate infections for a total of 30 infections). Twenty-five infections were treated with oral antibiotics, 9 were treated with intravenous antibiotics, and 11 required explantation of the entire implanted device (lead wire and IPG). Seventeen infections had culture data available: 10 (71%) grew MRSA, 4 grew methicillin-sensitive S. aureus (MSSA), 1 grew Pseudomonas aeruginosa, 1 grew group C Streptococcus, and 1 grew yeast (not speciated). Nine (75%) of the 12 patients who underwent explantation had wound cultures positive for MRSA (Table 2). See Appendix 1 for further details of each infection, the organism, and treatment summary. Thirteen of the 26 patients who developed infection had medical histories significant for immunosuppression. Eight patients had diabetes mellitus (1 of which was insulin dependent), 2 were smokers, and 2 had multiple sclerosis receiving chronic steroids. Of the 3 patients with late-onset infection, 2 were significant for immunosuppression. One patient with diet-controlled diabetes mellitus developed cellulitis at the surgical site 257 days after stage 2 SNM surgery. Another patient began chemotherapy for colon cancer and developed a surgical site abscess 687 days after stage 2 SNM surgery; this same patient had previously been successfully treated for cellulitis and abscess on postoperative day 14 from the index surgery with oral antibiotics and abscess drainage. The median TABLE 1. Descriptive Findings Characteristic No. of patients identified No. of patients included Median age, y Median parity Median BMI, kg/m2 Median days between stage 1 and stage 2 Median follow-up time, mo
n (Range) 319 290 65 (16–90) 2 (0–13) 26.6 (14.1–49) 14 (6–44) 12 (0–132)
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TABLE 2. Infectious Organisms/Treatment Summary No. of Infections 10 4 1 1 1
Organism Present on Culture
No. of Infections
Treatment Received
MRSA MSSA P. aeruginosa Group C β-hemolytic Streptococcus Yeast (not speciated)
25 9 11
Oral antibiotics Intravenous antibiotics Device removal
A retrospective analysis by Guralnick et al22 of 76 consecutive patients reported an infection rate of 18% (14 of 76 patients) and found that operative time for stage 2 (68 vs 52 minutes in the group with and without infection, respectively) was a statistically significant predictor of surgical site infection. Additional risk factors for infection reviewed in that study include number of days between stages 1 and 2, current smoking, steroid use, and diabetes, and the study found that these were not independently correlated with surgical site infection; however, an aggregate analysis of immunosuppression was not performed. Similar to the present study, Guralnick et al22 also reported that S. aureus was the predominant organism involved in their infected patients. They make an interesting note that the majority of the infections were sensitive to the perioperative antibiotics given at the time of surgery. The authors hypothesize that this may be due to under dosing of the perioperative antibiotic but do state that the currently accepted dose per body weight had been used. Interestingly, Guralnick et al22 report not prescribing oral prophylactic antibiotics during the trial phase of therapy while the lead wire extension is exposed. All infections in their study occurred within 1 month of surgery, and the average follow-up time was not reported. In contrast to Guralnick et al,22 we did not examine length of surgical time in the present study. Furthermore, because of the increased infectious risk associated with externalized hardware, we do routinely prescribe daily antibiotic prophylaxis during the trial phase of therapy. Another commonly cited study regarding infection in the setting of SNM procedures was performed by Wexner et al.7 They reported infection rates in a large investigational trial of sacral nerve stimulation for fecal incontinence. One hundred twenty subjects (92% were female; mean age, 60.5 ± 12.5 years) received a chronically implanted InterStim therapy device (Medtronic) and were followed up for an average of 28 months. They reported infections in 13 (10.8%) of the 120 implanted subjects. One infection resolved spontaneously, 5 (4.1%) were successfully treated with antibiotics, and 7 (5.8%) required surgical intervention. Six infected patients (5.0%) required full permanent device explantation. Nine infections occurred within a month of chronic system implant, whereas 4 infections occurred more than a year from implantation. Seven of 9 early infections were able to be treated conservatively; however, all 4 of the late infections required permanent system explantation. The following possible risk factors for infection were compared between patients with and without infection: age, BMI, and surgical time of both stages 1 and 2. None of these
time between the most recent SNM procedure and development of infection was 14 days (range, 2–687 days). Of the 254 patients with a reported indication for surgery, 62 patients underwent SNM surgery for fecal incontinence, whereas 192 had nonfecal indications. Three (4.6%) of the 62 patients with fecal incontinence developed infection, whereas 21 (9.9%) of the 192 with nonfecal indications for surgery developed infection. This was not statistically significant: P = 0.188 (Tables 3A and 3B). There were 323 procedures performed prior to and 346 procedures performed after institution of home CHW. Twenty-four (80%) of the 30 infections were prior to CHW, and 6 (20%) after institution of CHW. Prior to CHW, the per-procedure infection rate was 7.4%. The infection rate after institution of CHW was 1.7% (P = 0.002) (Table 4). Of the 83 patients with compliance data available for CHW use, 71 reported using CHW, whereas 12 reported not using CHW. There was one infection among the 83 patients with CHW compliance data available, and this patient reported using CHW the night prior but not the morning of surgery. In multivariate analysis, immunosuppression (P = 0.028) and BMI (P = 0.029) were found to remain statistically significant independent predictors of infection. Age (P = 0.278) and fecal incontinence (P = 0.464) were not associated with infection. In a model including only patients undergoing both stages 1 and 2 procedures, the number of days between procedures was not a predictor of infection (P = 0.486) (Table 5).
DISCUSSION Surgical site infection can be a devastating complication often requiring prolonged hospitalization, additional medical therapy, and reoperation.18 The incidence of surgical site infection varies by procedure performed but globally is reported between 1% and 4%.19 Historically, revision rates for SNM have been as high as 33% with pain, lead migration, and infection being the most common causes of revision.20 While contemporary reports suggest that revision rates and incidence of infection have improved significantly,21 surgical site infections remain a significant complication of SNM. In the present study, we sought to identify risk factors for surgical site infection in patients undergoing SNM procedures. In addition, we evaluated the impact of home CHW to decrease the incidence of surgical site infection.
TABLE 3A. Indications for Sacral Nerve Stimulation Procedure (All Patients)
No. of patients with this indication
Urinary Urge Incontinence
Urgency-Frequency
Nonobstructive Urinary Retention
Fecal Incontinence
179
131
46
62
*Many patients had more than 1 indication for sacral nerve stimulation.
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
TABLE 3B. Indications for Sacral Nerve Stimulation Broken Down by Fecal or Nonfecal Indication
No. of patients with this indication No. of patients with infection
Nonfecal
Fecal
P
192 21 (9.9%)
62 3 (4.6%)
0.188*
*Fisher exact t test.
comparisons showed a statistically significant difference between the groups. Similar to Wexner and colleagues’7 trial, we also report 3 cases of late infection occurring 234, 257, and 687 days after surgery. The latter of these 3 patients developed a surgical site cellulitis and abscess 13 days postoperatively that were successfully managed with oral antibiotics and drainage; however, after beginning chemotherapy for colon cancer 22 months later, an abscess developed at the surgical site, and the device had to be explanted. The development of infection after the skin has closed suggests that bacteria were present in the wound from the time of surgery. Late infections at surgical sites have been reported in other surgical procedures involving implanted hardware, with approximately 25% of prosthetic joint infections in Medicare patients occurring more than 2 years after inplantation.23 Longer operative time has been described as a risk factor for SSI in arthroplasty.23 In addition, the Charlson score (a composite index of medical comorbidities intended to predict 10-year mortality) has been correlated with readmission in prosthetic joint replacement patients but not surgical site infection.24 Our overall infection rate of 4.4% is lower than previously reported for SNM surgery. In addition, the present study provides additional information regarding risk factors for infection associated with SNM surgery. We found that 50% of the patients who developed an infection had medical history significant for potentially being immunosuppressed, most notably diabetes. Immunosuppression and BMI remained statistically significant independent predictors of infection in multivariate analysis. Importantly, 10 of 17 of the culture proven infections grew MRSA, suggesting that this organism should be covered empirically when antibiotic selection is made. Indication for procedure does not appear to be a risk factor for infection. Finally, the results of this study suggest that the change in our practice pattern to implement CHW prior to SNM surgery appears to result in a significant decrease in surgical site infection rate in this population. The data also suggest that prophylactic coverage for MRSA may be an effective strategy to reduce infection. We have now universally adopted this in our practice with daily oral trimethoprim-sulfamethoxazole during the trial phase of therapy and intravenous vancomycin prior to surgery. TABLE 4. No. of Infections Infection Yes No Total no. of procedures Rate per procedure prior to and after 2008
Sacral Nerve Modulation Therapy
TABLE 5. Multivariate Analysis Risk Factor
Odds Ratio
95% Confidence Interval
P
Immunosuppression BMI Age Fecal incontinence Days between stages 1 and 2*
2.95 1.08 1.02 0.61 1.03
1.12–7.77 1.01–1.16 0.98–1.06 0.16–2.29 0.95–1.12
0.028 0.029 0.278 0.464 0.486
*This risk factor was analyzed using a model that included only patients undergoing both stages 1 and 2.
The strengths of this study include the large number of patients’ records reviewed and the report of bacterial cultures with sensitivities. In addition, a strong correlation is suggested by identification of a single change in practice pattern after which a significant decrease in surgical site infections occurred. The weaknesses include the retrospective design and incomplete data on CHW compliance. Also, in July 2006, a smaller battery became available for use during IPG placement. It is possible that use of different battery sizes may be correlated with infection rate because of less subcutaneous dissection. Additional prospective trials should be performed to further elucidate risk factors for SSI in patients undergoing SNM surgery and the role of CHW and MRSA prophylaxis in this population. REFERENCES 1. Coyne KS, Sexton CC, Thompson CL, et al. The prevalence of lower urinary tract symptoms (LUTS) in the USA, the UK and Sweden: results from the Epidemiology of LUTS (EpiLUTS) study. BJU Int 2009; 104(3):352–360. 2. Siegel SW, Catanzaro F, Dijkema HE, et al. Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention. Urology 2000;56 (6 suppl 1):87–91. Available at: http://www.ncbi.nlm.nih.gov/ pubmed/11114569. Accessed March 20, 2013. 3. Michelsen HB, Thompson-Fawcett M, Lundby L, et al. Six years of experience with sacral nerve stimulation for fecal incontinence. Dis Colon Rectum 2010;53(4):414–421. 4. Melenhorst J, Koch SM, Uludag O, et al. Is a morphologically intact anal sphincter necessary for success with sacral nerve modulation in patients with faecal incontinence? Colorectal Dis 2008; 10(3):257–262. 5. Takano S, Boutros M, Wexner SD. Sacral nerve stimulation for fecal incontinence. Dis Colon Rectum 2013;56(3):384. 6. Iachetta RP, Cola A, Villani RD. Sacral nerve stimulation in the treatment of fecal incontinence—the experience of a pelvic floor center: short term results. J Interv Gastroenterol 2012;2(4):189–192.
Before 2008
After 2008
Total
7. Wexner SD, Hull T, Edden Y, et al. Infection rates in a large investigational trial of sacral nerve stimulation for fecal incontinence. J Gastrointest Surg 2010;14(7):1081–1089.
24 (80%) 299 323
6 (20%) 340 346
30 639 669
8. Huwyler M, Kiss G, Burkhard FC, et al. Microbiological tined-lead examination: does prolonged sacral neuromodulation testing induce infection? BJU Int 2009;104(5):646–650 discussion 650.
24/323 = 0.074
6/346 = 0.017
P = 0.002*
*Fisher exact test.
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9. Simpson JA, Peacock J, Maxwell-Armstrong C. Use of a gentamicin-impregnated collagen sheet (Collatamp(®) ) following implantation of a sacral nerve stimulator for faecal incontinence. Colorectal Dis 2012;14(4):e200–e202. 10. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Centers for Disease Control and
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control 1999;27(2):97–132; quiz 133–134; discussion 96. Available at: http://www.ncbi.nlm.nih.gov/ pubmed/10196487. Accessed November 4, 2013. 11. Climo MW, Yokoe DS, Warren DK, et al. Effect of daily chlorhexidine bathing on hospital-acquired infection. N Engl J Med 2013;368(6):533–542. 12. Milstone AM, Elward A, Song X, et al. Daily chlorhexidine bathing to reduce bacteraemia in critically ill children: a multicentre, cluster-randomised, crossover trial. Lancet 2013;6736(12):1–8. 13. Johnson AJ, Daley J a, Zywiel MG, et al. Preoperative chlorhexidine preparation and the incidence of surgical site infections after hip arthroplasty. J Arthroplasty 2010;25(6 Suppl):98–102. 14. Eiselt D. Presurgical skin preparation with a novel 2% chlorhexidine gluconate cloth reduces rates of surgical site infection in orthopaedic surgical patients. Orthop Nurs 2009;28(3):141–145. 15. Graling PR, Vasaly FW. Effectiveness of 2% CHG cloth bathing for reducing surgical site infections. AORN J 2013;97 (5):547–551. 16. Farber NJ, Chen AF, Bartsch SM, et al. No infection reduction using chlorhexidine wipes in total joint arthroplasty. Clin Orthop Relat Res 2013;471(10):3126–3127.
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17. Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Rev 2012;9(9):CD004985. 18. Chlebicki MP, Safdar N, O’Horo JC, et al. Preoperative chlorhexidine shower or bath for prevention of surgical site infection: a meta-analysis. Am J Infect Control 2013;41(2):167–173. 19. Haynes AB, Weiser TG, Berry WR, et al. A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med 2009;360(5):491–499. 20. Brazzelli M, Murray A, Fraser C. Efficacy and safety of sacral nerve stimulation for urinary urge incontinence: a systematic review. J Urol 2006;175(3 pt 1):835–841. 21. Pettit P. Current opinion: complications and troubleshooting of sacral neuromodulation. Int Urogynecol J 2010;21(suppl 2):S491–S496. 22. Guralnick ML, Benouni S, O’Connor RC, et al. Characteristics of infections in patients undergoing staged implantation for sacral nerve stimulation. Urology 2007;69(6):1073–1076. 23. Kurtz SM, Ong KL, Lau E, et al. Prosthetic joint infection risk after TKA in the Medicare population. Clin Orthop Relat Res 2010;468(1):52–56. 24. Voskuijl T, Hageman M, Ring D. Higher Charlson Comorbidity Index scores are associated with readmission after orthopaedic surgery. Clin Orthop Relat Res 2014;472(5):1638–1644.
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
Sacral Nerve Modulation Therapy
Appendix 1: Infections With Culture Data Available
Patient No.
Organism
58*
MSSA
58*
MSSA
74
MRSA
78†
MRSA
78†
MRSA
120
MRSA
130
MRSA
155
MRSA
193
P. aeruginosa
206
MRSA
226
233
268
273 281 298
313
Infection site Cellulitis at IPG site Cellulitis at second IPG site Cellulitis of lead wire exit site
Treatment Oral antibiotics Oral antibiotics Oral antibiotics resolved cellulitis, but pain persisted, and the lead wire was removed, IPG not implanted Oral antibiotics
Abscess of IPG site Recurrence of abscess Oral antibiotics, of IPG site after explantation beginning chemotherapy Cellulitis of Oral and Intravenous IPG site antibiotics, explantation Purulent fluid at Replacement of lead wire exit lead wire at time site noted at of stage 2 time of stage 2 Cellulitis at lead Intravenous antibiotics wire exit site followed by lead wire replacement Cellulitis at lead Oral antibiotics wire exit site Cellulitis at lead wire exit site
Incision and drainage, lead wire removal. IPG not implanted MRSA Abscess and cellulitis Oral antibiotics, at lead wire exit site Incision and drainage, lead wire removal, IPG not implanted Group C Abscess and Intravenous antibiotics, β-hemolytic cellulitis at explantation Streptococcus IPG site MRSA Cellulitis at lead Oral and Intravenous wire exit site antibiotics and extension pocket MRSA Abscess at Intravenous antibiotics, IPG site explantation Dermatosis at lead Oral antifungal Yeast—not speciated wire exit site MSSA Cellullitis and Oral antibiotics, wound seroma explantation of IPG site MSSA Cellulitis at Oral and Intravenous IPG site antibiotics, explanation
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Days Between Chlorhexidine Procedure and Use Infection
Immunosuppression?
Prior to institution of CHW Prior to institution of CHW Yes
257
10
Yes—diabetes mellitus, non–insulin dependent Yes—diabetes mellitus, non–insulin dependent No
Prior to institution of CHW Prior to institution of CHW
14
No
13
687
Yes—began chemotherapy for colon cancer
Prior to institution of CHW
35
No
After institution of CHW but data not available
14
No
Prior to institution of CHW
21
No
After institution of CHW but data not available Prior to institution of CHW
14
No
17
After institution of CHW but data not available
14
Yes—on chronic steroids for multiple sclerosis Yes—diabetes mellitus, non–insulin dependent
After institution of CHW but data not available Prior to institution of CHW
15
Yes—smoker
13
Yes—diabetes mellitus, non–insulin dependent
Prior to institution of CHW Prior to institution of CHW Prior to institution of CHW
234
No
14
No
7
Yes—smoker
Prior to institution of CHW
6
No
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Appendix 1 Continued
Organism
Infection site
Treatment
Chlorhexidine Use
Days Between Procedure and Infection
8
N/A
Oral antibiotics
Prior to institution of CHW
8
No
36 70
N/A N/A
Cellulitis at incision site after IPG removal Cellulitis at IPG site Cellulitis at IPG site
Oral antibiotics Oral antibiotics
9 16
87
N/A
Oral antibiotics
105 135
N/A N/A
Cellulitis at lead wire exit site Cellulitis at IPG site Cellulitis at IPG site
Prior to institution of CHW After institution of CHW but data not available Prior to institution of CHW
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
13 20
139* 139*
N/A N/A
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
8 10
217
N/A
Cellulitis at IPG site Cellulitis at second lead wire exit site Cellulitis at IPG site
No Yes—diabetes mellitus, non–insulin dependent Yes—diabetes mellitus, non–insulin dependent No Yes—on chronic steroids for multiple sclerosis No No
Oral antibiotics
Prior to institution of CHW
23
242*
N/A
Oral antibiotics
Prior to institution of CHW
2
242* 257
N/A N/A
Cellulitis at lead wire exit site Cellulitis at IPG site Cellulitis at IPG site
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
3 16
310
N/A
Cellulitis at IPG site
Oral antibiotics
Prior to institution of CHW
3
Patient No.
6
Immunosuppression?
Yes—diabetes mellitus, diet controlled No No Yes—Insulin dependent diabetes mellitus Yes—diabetes mellitus, non–insulin dependent
*These patients had more than 1 infection, each of which was associated with an additional procedure. † This patient developed recurrence of abscess at the IPG site after beginning chemotherapy 687 days after her IPG placement. Intravenous indicates intravenous.
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Risk Factors for Surgical Site Infection in Patients Undergoing Sacral Nerve Modulation Therapy Taylor Brueseke, MD, Briana Livingston, MD, Hussein Warda, MD, Kathryn Osann, PhD, and Karen Noblett, MD
Objectives: The aim of this study was to identify risk factors for surgical site infection in patients undergoing sacral nerve modulation (SNM) surgery.
Methods: We conducted a retrospective cohort analysis of 290 patients undergoing a total of 669 SNM procedures between 2002 and 2012 by 2 fellowship-trained female pelvic medicine and reconstructive surgery attending physicians at the University of California–Irvine Medical Center. Infection was defined as a charted abnormal examination finding at the implantation site (erythema, induration, purulent discharge) resulting in prescription of antibiotics, hospitalization, or explantation. We extracted information from the medical record regarding possible risk factors for infection including age, body mass index, immunosuppression (diabetes mellitus, chronic steroid use, smoker, chemotherapy), number of procedures per patient, and number of days between stages 1 and 2. In addition, we compared infection rates before and after 2008 when a clinical practice change was made with the implementation of home chlorhexidine washing (CHW) prior to SNM surgery. Results: Thirty infections occurred, 25 of which were managed with oral antibiotics. Nine required intravenous antibiotics, and 11 required removal of the implanted device. Three patients experienced infection on 2 separate occasions. Seventeen infections had culture data available. Nine of the patients who underwent explantation had wound cultures positive for methicillin-resistant Staphylococcus aureus. Thirteen of the 26 patients who developed infection had medical histories significant for immunosuppression. Three patients developed late-onset abscess formation at 234, 257, and 687 days after stage 2, respectively. The median time between the most recent SNM procedure and development of infection was 14 days (range, 6–88 days). Body mass index and immunosuppression were significant predictors of infection, whereas age, parity, indication for procedure, and number of days between stages 1 and 2 were not found to be independent predictors. Three hundred twenty-three procedures were performed prior to and 346 procedures were performed after institution of home CHW. Twentyfour (80%) of the 30 reported infections were prior to CHW, whereas only 6 infections (20%) occurred after this change in practice. Prior to institution of CHW, the infection rate was 7.4%, and after institution of CHW, it was 1.7% (P = 0.002). Of the 83 patients with compliance data available for CHW use, 71 reported using CHW, whereas 12 reported not using CHW. Conclusions: Surgical site infection is a significant risk of SNM surgery, although our infection rate is lower than previously reported. Chlorhexidine washing appears to reduce the risk of infection in this population. Because the majority of infections requiring explantation were methicillin-resistant S. aureus positive, prophylactic treatment for this organism should be considered as an additional strategy to reduce infection. Body mass index and immunosuppression appear to be independent risk factors for infection. Key Words: sacral nerve modulation, risk factors, infection, chlorhexidine gluconate From the Division of Urogynecology, Department of Obstetrics and Gynecology, University of California–Irvine, Orange, CA. Reprints: Karen Noblett, MD, University of California–Irvine, 101 The City Dr S Bldg 56, Suite 800, Orange, CA 92868. E-mail: [email protected]. The authors declare that they have nothing to disclose. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/SPV.0000000000000183
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O
veractive bladder is a prevalent condition that is reported to effect one third of adults older than 40 years.1 Treatment modalities for this condition can be broadly categorized into conservative (including lifestyle changes, pelvic floor physical therapy, or medications) and procedural/surgical. Sacral nerve modulation (SNM) is a minimally invasive procedure that is Food and Drug Administration approved for the treatment of urgency incontinence, urgency-frequency syndrome, nonobstructive urinary retention, and fecal incontinence. Sacral nerve modulation delivers nonpainful, mild electrical pulses to the sacral nerves to modulate the reflexes that influence the bladder, sphincters, and pelvic floor to improve or restore normal voiding and defecatory functions. Device implantation is generally performed in 2 stages as described by Siegel et al.2 The first stage involves percutaneous placement of a quadripolar lead wire adjacent to the S3 nerve root, which is connected to an external pulse generator. A reduction of 50% in symptoms or greater, depending on the indication for implantation, is considered a successful response to therapy and is an indication for implantation of the chronic device. Stage 2 consists of implantation of the implantable pulse generator (IPG) in the upper buttock area. Currently, the only commercially available SNM device is Interstim (Medtronic, Minneapolis, Minn), which has been available in the United States since 1997. Since its introduction, SNM has undergone significant improvements in design and application so that implantation is now a minimally invasive procedure performed under local anesthesia and intravenous sedation. Despite the progress made in advancing this therapy to a minimally invasive procedure, significant adverse events may occur. The rate of surgical site infection has been reported to be between 1% and 23%.3–7 Length of time between stages 1 and 2 has not been shown to be predictive of risk of infection.8 Use of gentamicin-impregnated collagen has been described as a potential method to reduce surgical site infections. In a small study of 8 patients who had a gentamicin-impregnated collagen sheet placed in the subcutaneous pocket at the time of pulse generator implantation, there were no reported infections over a median of 89 days of follow-up.9 Currently, there is a paucity of data to help inform us on best practices in the preoperative and postoperative period to decrease infection rates in SNM procedures. In an effort to reduce surgical site infection, the Centers for Disease Control has recommended home bathing with an antiseptic agent on at least the night prior to and morning of surgery.10 Chlorhexidine gluconate is a broad-spectrum topical antibiotic that disrupts the cell membrane of bacteria, the daily use of which has recently gained national attention for decreasing the rate of multidrug-resistant hospital-acquired bloodstream infections in intensive care unit patients.11,12 Prospective cohort studies with historical controls have shown a decrease in surgical site infection after implementation of home and in-hospital preoperative chlorhexidine wiping13,14 and also in-hospital preoperative wiping alone.15 Retrospective
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
studies16 and all-modality inclusive meta-analysis17 have not shown significant reductions in surgical site infection. However, interpretation of the literature surrounding the use of chlorhexidine bathing to reduce surgical site infection is complicated by the diversity of study designs used. Variations include the mechanism of chlorhexidine administration: wiping (chlorhexidine impregnated wipes) versus washes (liquid chlorhexidine packets or bottles that are instructed to be applied to a washcloth and used in a shower) versus baths (liquid chlorhexidine that is to be added to a full-body bath). Additional complexity is encountered regarding the timing, frequency, and setting of chlorhexidine administration: 1-wash versus multiple, in-hospital preoperative application only versus home application with or without in-hospital preoperative application. Studies including home application vary on the number of applications to administer. In 2007, 4 of our patients experienced surgical site infections, 3 of which were from methicillin-resistant Staphylococcus aureus (MRSA). These occurred temporally very close together, and this prompted a change in our practice by instituting a home chlorhexidine wash: once at night the day before surgery and again the morning of surgery. This is the only identifiable practice change that occurred between the time periods before and after 2008 when this practice was implemented. We present a retrospective cohort analysis of 290 patients who underwent 668 SNM surgical procedures. Our purpose was to identify preoperative and postoperative risk factors associated with surgical site infections. In addition, we evaluated the effectiveness of chlorhexidine washing (CHW) to decrease SNM procedure surgical site infection rates.
METHODS After institutional review board approval, we conducted a retrospective cohort analysis of female patients undergoing SNM procedures between 2002 and 2012 by 2 fellowship-trained Female Pelvic Medicine and Reconstructive Surgery. Patients were identified by CPT codes 64581 and 64590. Charts were excluded if there was incomplete follow-up or documentation. We extracted information from the medical record regarding possible risk factors for infection including age, body mass index (BMI), immunocompromised state (diabetes mellitus, chronic steroid use, current smoker, chemotherapy), number of stages 1 and 2 procedures, and number of days between the stage 1 and stage 2 procedures. Information regarding indication for the procedure was also extracted. Standard practice at our institution has been to utilize a staged approach to SNM. We offer office-based peripheral nerve evaluation and operating room–based placement of the lead wire. When stage 1 is performed in the operating room, a tined lead wire is placed adjacent to the S3 nerve root and then tunneled underneath the skin to a pocket created in the subcutaneous tissue of the ipsilateral buttocks where it is joined to an extension wire. The extension wire is then tunneled underneath the skin to an exit site in the contralateral buttocks and connected to an external pulse generator. Non-tined leads were used in office-based peripheral nerve evaluations. Tined leads were used in operating room–based procedures. No fascial or periosteal anchoring was performed during this time period. We administer perioperative intravenous antibiotics and postoperative oral daily antibiotic prophylaxis between stages 1 and 2. Neither this practice nor the antibiotic selection changed during the study period. We used an iodine-based surgical preparation at the time of surgery throughout the study period. Infection was defined as a documented abnormal examination finding at the lead wire exit site, extension wire connector pocket, or IPG insertion site (erythema, induration, purulent © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Sacral Nerve Modulation Therapy
discharge), resulting in prescription of antibiotics, hospitalization, or device removal. Prior to 2008, patients at our institution undergoing SNM surgery did not receive preoperative instructions to perform home CHW. Beginning in 2008, patients were routinely provided with liquid 4% chlorhexidine gluconate and instructed to shower with it the night before surgery and the morning of surgery. They were instructed to liberally apply the solution to a washcloth or mesh sponge and to massage the solution into all areas of external skin. Patients were instructed to leave the chlorhexidine on their skin for 2 minutes and then to rinse with clean water and dry with a clean towel. Data regarding patient compliance with CHW are available from 2011 to 2012 (coinciding with the implementation of an electronic medical record in our preoperative holding area) and were documented by nursing staff in the preoperative holding area the day of surgery. Descriptive data are reported using mean, median, and range. Rates of infection before and after 2008 are compared using Fisher exact test. Univariate and multivariate analyses were performed.
RESULTS We identified 319 patient records, 290 of which met the above criteria and underwent a total of 669 SNM procedures (359 stage 1 and 310 stage 2). Mean age was 65 years (range, 16–90 years). Median BMI was 26.6 kg/m2 (range, 14–49 kg/m2). Median length of time between stage 1 and stage 2 was 14 days. Median follow-up time was 12 months (Table 1). Twenty-six patients (3.8%) developed an infection (4 patients experienced 2 separate infections for a total of 30 infections). Twenty-five infections were treated with oral antibiotics, 9 were treated with intravenous antibiotics, and 11 required explantation of the entire implanted device (lead wire and IPG). Seventeen infections had culture data available: 10 (71%) grew MRSA, 4 grew methicillin-sensitive S. aureus (MSSA), 1 grew Pseudomonas aeruginosa, 1 grew group C Streptococcus, and 1 grew yeast (not speciated). Nine (75%) of the 12 patients who underwent explantation had wound cultures positive for MRSA (Table 2). See Appendix 1 for further details of each infection, the organism, and treatment summary. Thirteen of the 26 patients who developed infection had medical histories significant for immunosuppression. Eight patients had diabetes mellitus (1 of which was insulin dependent), 2 were smokers, and 2 had multiple sclerosis receiving chronic steroids. Of the 3 patients with late-onset infection, 2 were significant for immunosuppression. One patient with diet-controlled diabetes mellitus developed cellulitis at the surgical site 257 days after stage 2 SNM surgery. Another patient began chemotherapy for colon cancer and developed a surgical site abscess 687 days after stage 2 SNM surgery; this same patient had previously been successfully treated for cellulitis and abscess on postoperative day 14 from the index surgery with oral antibiotics and abscess drainage. The median TABLE 1. Descriptive Findings Characteristic No. of patients identified No. of patients included Median age, y Median parity Median BMI, kg/m2 Median days between stage 1 and stage 2 Median follow-up time, mo
n (Range) 319 290 65 (16–90) 2 (0–13) 26.6 (14.1–49) 14 (6–44) 12 (0–132)
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TABLE 2. Infectious Organisms/Treatment Summary No. of Infections 10 4 1 1 1
Organism Present on Culture
No. of Infections
Treatment Received
MRSA MSSA P. aeruginosa Group C β-hemolytic Streptococcus Yeast (not speciated)
25 9 11
Oral antibiotics Intravenous antibiotics Device removal
A retrospective analysis by Guralnick et al22 of 76 consecutive patients reported an infection rate of 18% (14 of 76 patients) and found that operative time for stage 2 (68 vs 52 minutes in the group with and without infection, respectively) was a statistically significant predictor of surgical site infection. Additional risk factors for infection reviewed in that study include number of days between stages 1 and 2, current smoking, steroid use, and diabetes, and the study found that these were not independently correlated with surgical site infection; however, an aggregate analysis of immunosuppression was not performed. Similar to the present study, Guralnick et al22 also reported that S. aureus was the predominant organism involved in their infected patients. They make an interesting note that the majority of the infections were sensitive to the perioperative antibiotics given at the time of surgery. The authors hypothesize that this may be due to under dosing of the perioperative antibiotic but do state that the currently accepted dose per body weight had been used. Interestingly, Guralnick et al22 report not prescribing oral prophylactic antibiotics during the trial phase of therapy while the lead wire extension is exposed. All infections in their study occurred within 1 month of surgery, and the average follow-up time was not reported. In contrast to Guralnick et al,22 we did not examine length of surgical time in the present study. Furthermore, because of the increased infectious risk associated with externalized hardware, we do routinely prescribe daily antibiotic prophylaxis during the trial phase of therapy. Another commonly cited study regarding infection in the setting of SNM procedures was performed by Wexner et al.7 They reported infection rates in a large investigational trial of sacral nerve stimulation for fecal incontinence. One hundred twenty subjects (92% were female; mean age, 60.5 ± 12.5 years) received a chronically implanted InterStim therapy device (Medtronic) and were followed up for an average of 28 months. They reported infections in 13 (10.8%) of the 120 implanted subjects. One infection resolved spontaneously, 5 (4.1%) were successfully treated with antibiotics, and 7 (5.8%) required surgical intervention. Six infected patients (5.0%) required full permanent device explantation. Nine infections occurred within a month of chronic system implant, whereas 4 infections occurred more than a year from implantation. Seven of 9 early infections were able to be treated conservatively; however, all 4 of the late infections required permanent system explantation. The following possible risk factors for infection were compared between patients with and without infection: age, BMI, and surgical time of both stages 1 and 2. None of these
time between the most recent SNM procedure and development of infection was 14 days (range, 2–687 days). Of the 254 patients with a reported indication for surgery, 62 patients underwent SNM surgery for fecal incontinence, whereas 192 had nonfecal indications. Three (4.6%) of the 62 patients with fecal incontinence developed infection, whereas 21 (9.9%) of the 192 with nonfecal indications for surgery developed infection. This was not statistically significant: P = 0.188 (Tables 3A and 3B). There were 323 procedures performed prior to and 346 procedures performed after institution of home CHW. Twenty-four (80%) of the 30 infections were prior to CHW, and 6 (20%) after institution of CHW. Prior to CHW, the per-procedure infection rate was 7.4%. The infection rate after institution of CHW was 1.7% (P = 0.002) (Table 4). Of the 83 patients with compliance data available for CHW use, 71 reported using CHW, whereas 12 reported not using CHW. There was one infection among the 83 patients with CHW compliance data available, and this patient reported using CHW the night prior but not the morning of surgery. In multivariate analysis, immunosuppression (P = 0.028) and BMI (P = 0.029) were found to remain statistically significant independent predictors of infection. Age (P = 0.278) and fecal incontinence (P = 0.464) were not associated with infection. In a model including only patients undergoing both stages 1 and 2 procedures, the number of days between procedures was not a predictor of infection (P = 0.486) (Table 5).
DISCUSSION Surgical site infection can be a devastating complication often requiring prolonged hospitalization, additional medical therapy, and reoperation.18 The incidence of surgical site infection varies by procedure performed but globally is reported between 1% and 4%.19 Historically, revision rates for SNM have been as high as 33% with pain, lead migration, and infection being the most common causes of revision.20 While contemporary reports suggest that revision rates and incidence of infection have improved significantly,21 surgical site infections remain a significant complication of SNM. In the present study, we sought to identify risk factors for surgical site infection in patients undergoing SNM procedures. In addition, we evaluated the impact of home CHW to decrease the incidence of surgical site infection.
TABLE 3A. Indications for Sacral Nerve Stimulation Procedure (All Patients)
No. of patients with this indication
Urinary Urge Incontinence
Urgency-Frequency
Nonobstructive Urinary Retention
Fecal Incontinence
179
131
46
62
*Many patients had more than 1 indication for sacral nerve stimulation.
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
TABLE 3B. Indications for Sacral Nerve Stimulation Broken Down by Fecal or Nonfecal Indication
No. of patients with this indication No. of patients with infection
Nonfecal
Fecal
P
192 21 (9.9%)
62 3 (4.6%)
0.188*
*Fisher exact t test.
comparisons showed a statistically significant difference between the groups. Similar to Wexner and colleagues’7 trial, we also report 3 cases of late infection occurring 234, 257, and 687 days after surgery. The latter of these 3 patients developed a surgical site cellulitis and abscess 13 days postoperatively that were successfully managed with oral antibiotics and drainage; however, after beginning chemotherapy for colon cancer 22 months later, an abscess developed at the surgical site, and the device had to be explanted. The development of infection after the skin has closed suggests that bacteria were present in the wound from the time of surgery. Late infections at surgical sites have been reported in other surgical procedures involving implanted hardware, with approximately 25% of prosthetic joint infections in Medicare patients occurring more than 2 years after inplantation.23 Longer operative time has been described as a risk factor for SSI in arthroplasty.23 In addition, the Charlson score (a composite index of medical comorbidities intended to predict 10-year mortality) has been correlated with readmission in prosthetic joint replacement patients but not surgical site infection.24 Our overall infection rate of 4.4% is lower than previously reported for SNM surgery. In addition, the present study provides additional information regarding risk factors for infection associated with SNM surgery. We found that 50% of the patients who developed an infection had medical history significant for potentially being immunosuppressed, most notably diabetes. Immunosuppression and BMI remained statistically significant independent predictors of infection in multivariate analysis. Importantly, 10 of 17 of the culture proven infections grew MRSA, suggesting that this organism should be covered empirically when antibiotic selection is made. Indication for procedure does not appear to be a risk factor for infection. Finally, the results of this study suggest that the change in our practice pattern to implement CHW prior to SNM surgery appears to result in a significant decrease in surgical site infection rate in this population. The data also suggest that prophylactic coverage for MRSA may be an effective strategy to reduce infection. We have now universally adopted this in our practice with daily oral trimethoprim-sulfamethoxazole during the trial phase of therapy and intravenous vancomycin prior to surgery. TABLE 4. No. of Infections Infection Yes No Total no. of procedures Rate per procedure prior to and after 2008
Sacral Nerve Modulation Therapy
TABLE 5. Multivariate Analysis Risk Factor
Odds Ratio
95% Confidence Interval
P
Immunosuppression BMI Age Fecal incontinence Days between stages 1 and 2*
2.95 1.08 1.02 0.61 1.03
1.12–7.77 1.01–1.16 0.98–1.06 0.16–2.29 0.95–1.12
0.028 0.029 0.278 0.464 0.486
*This risk factor was analyzed using a model that included only patients undergoing both stages 1 and 2.
The strengths of this study include the large number of patients’ records reviewed and the report of bacterial cultures with sensitivities. In addition, a strong correlation is suggested by identification of a single change in practice pattern after which a significant decrease in surgical site infections occurred. The weaknesses include the retrospective design and incomplete data on CHW compliance. Also, in July 2006, a smaller battery became available for use during IPG placement. It is possible that use of different battery sizes may be correlated with infection rate because of less subcutaneous dissection. Additional prospective trials should be performed to further elucidate risk factors for SSI in patients undergoing SNM surgery and the role of CHW and MRSA prophylaxis in this population. REFERENCES 1. Coyne KS, Sexton CC, Thompson CL, et al. The prevalence of lower urinary tract symptoms (LUTS) in the USA, the UK and Sweden: results from the Epidemiology of LUTS (EpiLUTS) study. BJU Int 2009; 104(3):352–360. 2. Siegel SW, Catanzaro F, Dijkema HE, et al. Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention. Urology 2000;56 (6 suppl 1):87–91. Available at: http://www.ncbi.nlm.nih.gov/ pubmed/11114569. Accessed March 20, 2013. 3. Michelsen HB, Thompson-Fawcett M, Lundby L, et al. Six years of experience with sacral nerve stimulation for fecal incontinence. Dis Colon Rectum 2010;53(4):414–421. 4. Melenhorst J, Koch SM, Uludag O, et al. Is a morphologically intact anal sphincter necessary for success with sacral nerve modulation in patients with faecal incontinence? Colorectal Dis 2008; 10(3):257–262. 5. Takano S, Boutros M, Wexner SD. Sacral nerve stimulation for fecal incontinence. Dis Colon Rectum 2013;56(3):384. 6. Iachetta RP, Cola A, Villani RD. Sacral nerve stimulation in the treatment of fecal incontinence—the experience of a pelvic floor center: short term results. J Interv Gastroenterol 2012;2(4):189–192.
Before 2008
After 2008
Total
7. Wexner SD, Hull T, Edden Y, et al. Infection rates in a large investigational trial of sacral nerve stimulation for fecal incontinence. J Gastrointest Surg 2010;14(7):1081–1089.
24 (80%) 299 323
6 (20%) 340 346
30 639 669
8. Huwyler M, Kiss G, Burkhard FC, et al. Microbiological tined-lead examination: does prolonged sacral neuromodulation testing induce infection? BJU Int 2009;104(5):646–650 discussion 650.
24/323 = 0.074
6/346 = 0.017
P = 0.002*
*Fisher exact test.
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9. Simpson JA, Peacock J, Maxwell-Armstrong C. Use of a gentamicin-impregnated collagen sheet (Collatamp(®) ) following implantation of a sacral nerve stimulator for faecal incontinence. Colorectal Dis 2012;14(4):e200–e202. 10. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Centers for Disease Control and
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control 1999;27(2):97–132; quiz 133–134; discussion 96. Available at: http://www.ncbi.nlm.nih.gov/ pubmed/10196487. Accessed November 4, 2013. 11. Climo MW, Yokoe DS, Warren DK, et al. Effect of daily chlorhexidine bathing on hospital-acquired infection. N Engl J Med 2013;368(6):533–542. 12. Milstone AM, Elward A, Song X, et al. Daily chlorhexidine bathing to reduce bacteraemia in critically ill children: a multicentre, cluster-randomised, crossover trial. Lancet 2013;6736(12):1–8. 13. Johnson AJ, Daley J a, Zywiel MG, et al. Preoperative chlorhexidine preparation and the incidence of surgical site infections after hip arthroplasty. J Arthroplasty 2010;25(6 Suppl):98–102. 14. Eiselt D. Presurgical skin preparation with a novel 2% chlorhexidine gluconate cloth reduces rates of surgical site infection in orthopaedic surgical patients. Orthop Nurs 2009;28(3):141–145. 15. Graling PR, Vasaly FW. Effectiveness of 2% CHG cloth bathing for reducing surgical site infections. AORN J 2013;97 (5):547–551. 16. Farber NJ, Chen AF, Bartsch SM, et al. No infection reduction using chlorhexidine wipes in total joint arthroplasty. Clin Orthop Relat Res 2013;471(10):3126–3127.
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17. Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Rev 2012;9(9):CD004985. 18. Chlebicki MP, Safdar N, O’Horo JC, et al. Preoperative chlorhexidine shower or bath for prevention of surgical site infection: a meta-analysis. Am J Infect Control 2013;41(2):167–173. 19. Haynes AB, Weiser TG, Berry WR, et al. A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med 2009;360(5):491–499. 20. Brazzelli M, Murray A, Fraser C. Efficacy and safety of sacral nerve stimulation for urinary urge incontinence: a systematic review. J Urol 2006;175(3 pt 1):835–841. 21. Pettit P. Current opinion: complications and troubleshooting of sacral neuromodulation. Int Urogynecol J 2010;21(suppl 2):S491–S496. 22. Guralnick ML, Benouni S, O’Connor RC, et al. Characteristics of infections in patients undergoing staged implantation for sacral nerve stimulation. Urology 2007;69(6):1073–1076. 23. Kurtz SM, Ong KL, Lau E, et al. Prosthetic joint infection risk after TKA in the Medicare population. Clin Orthop Relat Res 2010;468(1):52–56. 24. Voskuijl T, Hageman M, Ring D. Higher Charlson Comorbidity Index scores are associated with readmission after orthopaedic surgery. Clin Orthop Relat Res 2014;472(5):1638–1644.
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
Sacral Nerve Modulation Therapy
Appendix 1: Infections With Culture Data Available
Patient No.
Organism
58*
MSSA
58*
MSSA
74
MRSA
78†
MRSA
78†
MRSA
120
MRSA
130
MRSA
155
MRSA
193
P. aeruginosa
206
MRSA
226
233
268
273 281 298
313
Infection site Cellulitis at IPG site Cellulitis at second IPG site Cellulitis of lead wire exit site
Treatment Oral antibiotics Oral antibiotics Oral antibiotics resolved cellulitis, but pain persisted, and the lead wire was removed, IPG not implanted Oral antibiotics
Abscess of IPG site Recurrence of abscess Oral antibiotics, of IPG site after explantation beginning chemotherapy Cellulitis of Oral and Intravenous IPG site antibiotics, explantation Purulent fluid at Replacement of lead wire exit lead wire at time site noted at of stage 2 time of stage 2 Cellulitis at lead Intravenous antibiotics wire exit site followed by lead wire replacement Cellulitis at lead Oral antibiotics wire exit site Cellulitis at lead wire exit site
Incision and drainage, lead wire removal. IPG not implanted MRSA Abscess and cellulitis Oral antibiotics, at lead wire exit site Incision and drainage, lead wire removal, IPG not implanted Group C Abscess and Intravenous antibiotics, β-hemolytic cellulitis at explantation Streptococcus IPG site MRSA Cellulitis at lead Oral and Intravenous wire exit site antibiotics and extension pocket MRSA Abscess at Intravenous antibiotics, IPG site explantation Dermatosis at lead Oral antifungal Yeast—not speciated wire exit site MSSA Cellullitis and Oral antibiotics, wound seroma explantation of IPG site MSSA Cellulitis at Oral and Intravenous IPG site antibiotics, explanation
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Days Between Chlorhexidine Procedure and Use Infection
Immunosuppression?
Prior to institution of CHW Prior to institution of CHW Yes
257
10
Yes—diabetes mellitus, non–insulin dependent Yes—diabetes mellitus, non–insulin dependent No
Prior to institution of CHW Prior to institution of CHW
14
No
13
687
Yes—began chemotherapy for colon cancer
Prior to institution of CHW
35
No
After institution of CHW but data not available
14
No
Prior to institution of CHW
21
No
After institution of CHW but data not available Prior to institution of CHW
14
No
17
After institution of CHW but data not available
14
Yes—on chronic steroids for multiple sclerosis Yes—diabetes mellitus, non–insulin dependent
After institution of CHW but data not available Prior to institution of CHW
15
Yes—smoker
13
Yes—diabetes mellitus, non–insulin dependent
Prior to institution of CHW Prior to institution of CHW Prior to institution of CHW
234
No
14
No
7
Yes—smoker
Prior to institution of CHW
6
No
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Female Pelvic Medicine & Reconstructive Surgery • Volume 21, Number 4, July/August 2015
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Appendix 1 Continued
Organism
Infection site
Treatment
Chlorhexidine Use
Days Between Procedure and Infection
8
N/A
Oral antibiotics
Prior to institution of CHW
8
No
36 70
N/A N/A
Cellulitis at incision site after IPG removal Cellulitis at IPG site Cellulitis at IPG site
Oral antibiotics Oral antibiotics
9 16
87
N/A
Oral antibiotics
105 135
N/A N/A
Cellulitis at lead wire exit site Cellulitis at IPG site Cellulitis at IPG site
Prior to institution of CHW After institution of CHW but data not available Prior to institution of CHW
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
13 20
139* 139*
N/A N/A
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
8 10
217
N/A
Cellulitis at IPG site Cellulitis at second lead wire exit site Cellulitis at IPG site
No Yes—diabetes mellitus, non–insulin dependent Yes—diabetes mellitus, non–insulin dependent No Yes—on chronic steroids for multiple sclerosis No No
Oral antibiotics
Prior to institution of CHW
23
242*
N/A
Oral antibiotics
Prior to institution of CHW
2
242* 257
N/A N/A
Cellulitis at lead wire exit site Cellulitis at IPG site Cellulitis at IPG site
Oral antibiotics Oral antibiotics
Prior to institution of CHW Prior to institution of CHW
3 16
310
N/A
Cellulitis at IPG site
Oral antibiotics
Prior to institution of CHW
3
Patient No.
6
Immunosuppression?
Yes—diabetes mellitus, diet controlled No No Yes—Insulin dependent diabetes mellitus Yes—diabetes mellitus, non–insulin dependent
*These patients had more than 1 infection, each of which was associated with an additional procedure. † This patient developed recurrence of abscess at the IPG site after beginning chemotherapy 687 days after her IPG placement. Intravenous indicates intravenous.
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