Penn Evidence-Based Literature Review (PEBLR)

Summarized highlights from contemporary literature in surgical and allied disciplines for general surgery residents.

MIS/Bariatrics

Bariatric Surgery versus Intensive Medical Therapy for Diabetes — 5-Year Outcomes
Schauer PR, STAMPEDE investigators et al. N Engl J Med. 2017 Feb
Contributor: Brett Ecker

Brief Summary

Synopsis: Randomized studies have demonstrated that bariatric surgery is superior to intensive medical therapy for the short-term control of type II diabetes mellitus, but long-term data is generally lacking. An earlier trial involving randomization to RYGB or biliopancreatic diversion supported the superiority of surgical management in the long-term glycemic control of obese patients with DMII, but did not include the currently popular sleeve gastrectomy. The STAMPEDE trial was a single-center RCT for diabetic patients (Hgb-A1c >7) with mild obesity (BMI 27 to 34) who were randomized 1:1:1 to intensive medical therapy plus either RYGB or sleeve gastrectomy. Five years post-randomization, bariatric surgery was superior to intensive medical therapy in terms of glycemic control, weight reduction, medication reduction, improvement in lipid levels, and reported quality of life. Specifically, patients who underwent RYGB (38.8%) or sleeve gastrectomy (36.2%) were more likely to maintain a Hgb-A1c <6.5% than were those who received intensive medical therapy alone (15.8%). This endpoint was achieved without glycemic medications for approximately 30% of surgically treated patients. RYGB was associated with greater weight loss than sleeve gastrectomy at 5 years, with need for fewer diabetes medications. The trial provides the first long-term randomized data on the efficacy of the sleeve gastrectomy for management of obesity-associated diabetes, particularly in the subset with mild obesity. Moreover, a shorter duration of diabetes (<8 years) was one of the main predictors of achieving long-term glycemic control following randomization, highlighting a role for early surgical intervention in the management of this patient subset. 

Discipline

Safety and Feasibility of Minimally Invasive Inguinal Lymph Node Dissection in Patients with Melanoma (SAFE-MILND)
Jakub et al. Ann Surg. 2017 Jan.
Contributor: Madalyn G. Neuwirth

Brief Summary

Synopsis: Current oncologic guidelines for inguinal lymph node dissections in patients with melanoma recommend a minimum of 10 harvested lymph nodes for adequate staging, regional disease control, and improved overall survival. However, the potential morbidity of lymphadenectomy, especially when performed in the inguinal basin (e.g., wound complications, lymphedema, etc.) can be debilitating. As such, a novel approach to minimizing complications of inguinal lymph node dissections has been described using a 3-trocar placement within the femoral triangle. This study is a multi-institutional prospective phase I/II clinical trial evaluating the efficacy and outcomes of this minimally invasive approach in 87 patients with melanoma, performed by 12 surgeons at 10 institutions. They reported a median number of 10 (IQR 6,13) lymph nodes excised during the procedure, with 20% having less than 8 lymph nodes removed which was compared to a mean number of 11 lymph nodes in the Sunbelt Trial and median of 11 lymph nodes in the MSLT-1 trial for open inguinal lymphadenectomies. The majority of adverse events experienced in 71% of the patients were grade I or II, with 54% developing some level of lymphedema during follow-up. Rate of conversion to traditional open procedure was 11.5%. Notable limitations of this study include the follow-up periods of only 30 and 90 days, with almost 50% dropout rate by the time of latest follow-up. This study was also in a relatively small cohort; there was wide variability in the number of operations performed by surgeons involved (1-24). Furthermore, there was no direct comparison to complications and outcomes for a control group of patients undergoing open inguinal lymphadenectomy by the same group. In light of these promising preliminary findings, further investigations are warranted to establish the true safety and efficacy parameters of this operation. 

Colon and Rectal Surgery/General Surgery

Early Closure of a Temporary Ileostomy in Patients with Rectal Cancer: a Multicenter Randomized Control Trial
Danielsen AK et al., Ann Surg 2017 Feb.
Contributor: Arjun N. Jeganathan

Brief Summary

Synopsis: The temporary ileostomy was introduced to decrease the clinical consequences of an anastomotic leak; however, it is associated with risk of dehydration and renal failure. The aim of this trial was to explore if morbidity and mortality was reduced within 12 months after rectal resection if the ileostomy was closed early (8-13 days) compared with late (minimum of 12 weeks). The patients were selected on day 1 to 4 after index surgery and evaluated with CT with rectal contrast and/or flexible sigmoidoscopy/rigid proctoscopy to rule out leak. Of the 418 patients assessed for eligibility, 127 patients were randomized and 15 patients were excluded after randomization, resulting in 55 in the early closure group and 57 in the late closure group. Many exclusion criteria were utilized, of which, suspected anastomotic leak accounted for n=37. Median time from index surgery to closure was 11 days in early group and 148 days in late group. The primary endpoint, or mean number of complications after index surgery up to the 12 months follow-up, was significantly lower in the early closure group (1.24) compared with the late closure group (2.88) (RR 0.42, p<0.0001). There were no significant between-group differences when comparing severe complications (>=Clavien-Dindo Grade III). The clear strengths of the study include the element of randomization as well as the ability to capture all tracked patient outcomes due to nationalized healthcare records. A study limitation is lack of data on the effect of early reversal vs. delayed closure on initiation of adjuvant chemotherapy. Another limitation of the study was that only 127 of 418 patients assessed were deemed safe for randomization in the study. Therefore, nearly 70% were excluded after the index rectal resection. However, if 30% of patients can have their ileostomies closed earlier, it is a safe and favorable option for those with no clinical or radiographic evidence of leak at their coloanal anastomosis. 

Perioperative Medicine/Allied

Bezlotoxumab for Prevention of Recurrent Clostridium difficile Infection
Wilcox et al., N Engl J Med 2017 Jan.
Contributor: Grace Lee

Brief Summary

Synopsis: No current therapy is approved to prevent C. difficile recurrence, which is more difficult to treat and requires more healthcare utilization than the initial episode. The authors conducted an international double-blind randomized placebo-controlled trial (MODIFY) assessing the addition of a single infusion of bezlotoxumab, a human monoclonal antibody against C.diff toxin B, to assess effect on initial clinical cure, recurrence prevention, and sustained cure from C.diff infection with 12 weeks follow-up. Results demonstrated no significant different in initial clinical cure and a statistically significant ~10% absolute reduction in C.diff recurrence and sustained cure with bezlotoxumab use. There were no significant differences in adverse events with the use of bezlotoxumab. Items of note regarding the study include: 1) the trial also tested actoxumab, a human monoclonal antibody against C.diff toxin A, which ended prematurely due to lack of efficacy and more deaths and adverse events when used alone during interim analysis, 2) this was an industry sponsored trial (Merck), 3) the antibiotic regimen (vancomycin vs. metronidazole vs. fidaxomicin) was not standardized by the trial but at the discretion of individual investigators, and 4) one can argue that the ~10% absolute reduction in C.diff recurrence is not clinically impressive, albeit statistically significant. 

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