Necrotizing Fasciitis of the Abdominal Wall after Laparoscopic Roux-en-Y Gastric Bypass by Joanna R. Crossett, MD, and William V. Rice, MD

| June 13, 2013

The Hole in the Wall with Samuel Szomstein, MD, FACS
Dedicated to providing a venue for interactive exchange of ideas, interesting topics, and surgical pearls from experts in repair of abdominal wall defects as they relate to bariatric surgery

A Message from Column Editor Samuel Szomstein, MD, FACS
Dear Readers of Bariatric Times:
I would like to welcome you to this installment of “The Hole in the Wall.” We are very pleased to have Drs. Joanna R. Crossett and William V. Rice from the Department of General Surgery, William Beaumont Army Medical Center, El Paso, Texas, as our guest experts. In this issue we will cover an uncommon but devastating complication—necrotizing fasciitis affecting the abdominal wall after bariatric surgery. We welcome their expertise, case presentation with successful treatment, comments, and recommendations.
Once again, welcome to The Hole in the Wall. We hope you will enjoy this column and we look forward to your questions, comments, and participation in future issues.
Samuel Szomstein, MD, FACS
This month’s installment by Joanna R. Crossett, MD, and William V. Rice, MD, Department of General Surgery, William Beaumont Army Medical Center, El Paso, Texas

Funding: No funding was provided.

Financial disclosures: The authors report no conflicts of interest relevant to the content of this article.

Necrotizing fasciitis is a devastating infectious process with a mortality rate of greater than 20 percent.[1 Rapid recognition of this disease process is critical, as mortality is positively correlated with increased time to intervention.[2] This case report describes the presentation and successful management of a patient with severe, life-threatening necrotizing fasciitis. A discussion of possible contributing factors, as well as areas where our practice may change, follows.

Presentation of Case
The patient, a 41-year-old woman with a body mass index (BMI) of 44kg/m,2 had undergone laparoscopic Roux-en-Y gastric bypass (RYGB) prior to presentation. Her past medical history included diabetes, hypertension, and hypothyroidism. Her surgical history consisted of a laparoscopic cholecystectomy and a vaginal hysterectomy. She took the following medications: glipizide, sitagliptin/metformin, valsartan/hydrochlorothiazide, and levothyroxine. She had no allergies, did not smoke, and did not drink alcohol.

The patient underwent an uncomplicated RYGB. The operation was performed in an antecolic, antegastric fashion, with a 100cm Roux limb. The gastrojejunal anastomosis was created using a circular stapler introduced through the 15mm port site in the left mid-abdomen. The routine intraoperative leak test using endoscopic air insufflation and saline submersion showed no leak. The 15mm port site fascia was closed with a single 0 polydioxanone suture using the Endo Close™ Trocar Site Closure Device (Covidien, Mansfield, Massachusetts). The skin incision at this site, which was approximately 4cm long, was partially closed with interrupted 4-0 absorbable sutures spaced about 1cm apart, with gauze packed between the sutures (Figure 1). Estimated blood loss was 25mL, and the patient’s lowest recorded intraoperative temperature was 35.9 degrees Celsius. The patient’s postoperative course was uneventful, and she was discharged on Postoperative Day (POD) 2. The patient was evaluated in the emergency room on POD 4 with complaints of left mid-abdominal pain, which she described as a muscle “spasm” of her abdominal wall. At that time, she was tolerating a liquid diet, well hydrated, and had normal vital signs and a normal postoperative physical exam. She was prescribed morphine elixir and methocarbamol.

The patient was next evaluated at her routine three-week postoperative visit. She reported the left mid-abdominal pain to be improved, although she was still taking the morphine elixir and had begun taking ibuprofen (which she was counseled to stop). All of her incisions were noted to be clean, dry, and intact, without signs of infection. Weight loss at that visit was 20 pounds. She had normal vital signs, was tolerating a pureed diet, and had normal bowel and bladder function. She was discharged from the clinic with scheduled follow-up in three weeks.

Eight days after the routine follow-up appointment (POD 28), the patient’s husband brought her to the emergency room (ER). He reported that the patient had noticed some new redness over the left lower quadrant (LLQ) of her abdomen earlier that day. However, after he arrived home from work that evening, he noticed she had developed a blackened area on her abdominal wall, an altered mental status, and increased abdominal pain. Her evaluation in the ER showed the following vital signs: blood pressure 125/55mmHg, pulse rate 90 beats per minute, respiratory rate 24 breaths per minute, temperature 36.6 degrees Celsius. Laboratory values were significant for a serum sodium level of 127mEq/L, glucose of 474mg/dL, white blood cell count of 27,300/uL, and a urinalysis that showed evidence of a urinary tract infection. On exam, she was ill appearing and confused. The left lower abdomen had a 10x20cm area of ecchymotic skin with bullae and was exquisitely tender to palpation (Figure 2). The suspected diagnosis was necrotizing fasciitis.

The patient was immediately started on intravenous antibiotics and underwent a noncontrast computed tomography (CT) scan of the abdomen to evaluate for an intra-abdominal etiology. The CT revealed air within the abdominal wall but no intra-abdominal pathology (Figure 3). The patient was briefly resuscitated in the intensive care unit, where blood, urine, and wound cultures were obtained, and she was subsequently taken to the operating room for wide debridement. She underwent extensive debridement of her abdominal wall, and had a V.A.C. (Kinetic Concepts, Inc., San Antonio, Texas) negative pressure wound dressing placed. The debridement specimen consisted of three fragments of abdominal wall tissue, measuring 32 x 18 x 10cm, 32 x 18 x 12cm, and 20 x 12 x 3.5cm.

The patient remained in the hospital for 13 days with minimal requirement for additional surgical debridement. The wound and urine cultures returned positive with a single organism, Klebsiella pneumoniae, which was sensitive to ampicillin/sulbactam. The patient’s white blood cell count and blood glucose and sodium levels normalized. She was ambulatory and tolerating a full liquid diet before she was discharged to an acute care facility for continued wound care and rehabilitation. The patient underwent successful skin grafting of the abdominal wound two months later (Figure 4)

Necrotizing fasciitis is an infectious process characterized by rapid spread of necrosis of the subcutaneous tissue and superficial fascia. Mortality for necrotizing fasciitis, more broadly categorized as necrotizing soft-tissue infection, has trended down only slightly over the past 30 years (27.8% mortality in published studies from 1980 to 1999, versus 21.7% mortality in studies from 1999 to 2008).[1] Mortality is positively correlated with both depth of primary infection site and time to intervention.[2] Necrotizing fasciitis is a concern for the bariatric surgeon in particular because obesity and diabetes are both risk factors for its development, and soft tissue trauma, which occurs during RYGB and other laparoscopic bariatric operations, is a common etiology.[3]

The most common bacteria responsible for necrotizing soft tissue infection are streptococci, followed by S. aureus. Most necrotizing infections are polymicrobial, with 4.4 organisms isolated per infection on average.[1] Monomicrobial necrotizing fasciitis caused by K. pneumoniae is rare in the United States. A careful review of the literature revealed three case reports of this occurrence in the United States, none of which were related to bariatric surgery.[4–6] However, there have been multiple case reports of monomicrobial K. pneumoniae necrotizing fasciitis in Asian countries and among patients with recent travel to Asia.[7,8] In fact, K. pneumoniae is considered a common cause of necrotizing fasciitis in Taiwan. A 2012 study performed in Taiwan documented monomicrobial K. pneumoniae necrotizing fasciitis in 15 patients.[9] All 15 of the patients in this study were diabetic, and an association between K. pneumoniae, necrotizing fasciitis, and diabetes was also noted in case reports by Ho and Hu,[8,10] who additionally found an association with liver abscesses.

Our patient did not have evidence of bacteremia; however, she had a urine culture positive for K. pneumoniae in addition to the wound culture. Although her wound culture was monomicrobial, she had received one dose of vancomycin before the wound culture was taken. This antibiotic could have suppressed the growth of other organisms present in the wound.
The cornerstone of treatment for necrotizing fasciitis is surgical debridement and intravenous antibiotics.[11] Hyperbaric oxygen therapy (HBOT) has been proposed as an adjuvant treatment for necrotizing fasciitis, but the benefit of HBOT in this disease process has not been convincingly demonstrated.[12,13]

In light of the occurrence of this rare complication of RYGB, we have looked closely at the surgical techniques used in this patient’s operation to identify any factors that could have contributed to her infection. The gastrojejunostomy was created using a circular stapler, which is common practice in our institution. The best method for creation of the gastrojejunostomy in RYGB has long been a topic of debate among bariatric surgeons. A 2008 survey of American Society for Bariatric Surgery practicing surgeons performing gastric bypass reported that 43 percent used a circular stapler technique (CS), 41 percent used a linear stapler technique (LS), and 21 percent performed a hand-sewn anastomosis (HS).[14] A more recent survey of 44 surgeons, published in 2011, reported 66 percent of surgeons using CS, 18 percent using HS, and 16 percent using LS, indicating that the circular stapler technique may have become more popular over time. This second study showed a higher rate of wound infection with CS compared with LS and HS (4.7% vs. 1.6% vs. 0.6%).[15] A meta-analysis published in 2011 comparing techniques for creation of the gastrojejunostomy again showed the LS technique to have lower rates of wound infection (RR, 0.38 for LS compared to CS). It also showed LS to have a decreased operative time and rate of stricture formation.[16]

In addition to the stapler type, the management of the skin incision through which the stapler was introduced was also scrutinized. There are several methods for managing this incision, none of which has proven clearly superior. At the time of this case, our practice was to suture the skin edges loosely with interrupted sutures and place wicks between them (Figure 1). Alternative methods include primary closure, delayed primary closure, closure by secondary intention, V.A.C. closure, closure over a penrose drain, and others. In this case, the patient’s incisions were all well-healed at her three-week visit, and did not show any evidence of infection. However, it seems likely that she did have an infectious process present deep in her abdominal wall at that visit, which was not visible on the surface.

Necrotizing fasciitis is an infectious process with a high mortality rate, and mortality is positively correlated with increased time to intervention. In light of this, rapid detection and diagnosis of this disease process is critical. Our case demonstrates an atypical time course for the presentation of the disease and underscores the need for clinicians to maintain a high index of suspicion. Our patient’s operation was 28 days prior to presentation, and her postoperative course had been uneventful until this complication developed. Although the data are not overwhelming, use of a linear stapler is associated with lower complication rates in RYGB, and the use of a circular stapler in this case could have been a factor contributing to this patient’s complication. Techniques for closure of the incision through which the stapler is introduced also vary among surgeons; in this case, the patient’s well-healed incision appears to have masked an underlying infection in progress.

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7.    Gunnarsson GJ, Brandt PB, Gad D, et al. Monomicrobial necrotizing fasciitis in a white male caused by hypermucoviscous Klebsiella pneumoniae. J Med Microbiol. 2009;58:1519–1521.
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9.    Cheng NC, Yu YC, Tai HC, et al. Recent trend of necrotizing fasciitis in Taiwan: focus on monomicrobial Klebsiella pneumoniae necrotizing fasciitis.  Clin Infect Dis. 2012;55:930–939.
10.    Hu BS, Lau YJ, Shi ZY, Lin YH. Necrotizing fasciitis associated with Klebsiella pneumoniae liver abscess. Clin Infect Dis. 1999;29:1360–1361.
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13.    Hassan Z, Mullins RF, Friedman BC, et al. Treating necrotizing fasciitis with or without hyperbaric oxygen therapy. Undersea Hyperb Med. 2010;37(2):115–123.
14.    Madan AK, Harper JL, Tichansky DS. Techniques of laparoscopic gastric bypass: on-line survey of American Society for Bariatric Surgery practicing surgeons. Surg Obes Relat Dis. 2008;4:166–173.
15.    Finks JF, Carlin A, Share D, et al. Effects of surgical techniques on clinical outcomes after laparoscopic gastric bypass—results from the Michigan Bariatric Surgery Collaborative. Surg Obes Relat Dis. 2011;7:284–189.
16.    Giordano S, Salminen P, Biancari F, Victorzon M. Linear stapler technique may be safer than circular in gastrojejunal anastomosis for laparoscopic Roux-en-Y gastric bypass: a meta-analysis of comparative studies. Obes Surg. 2011;21:1958–1964.

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