INTRODUCTION
Enteroenteric fistulas occur in 5% to 30% of patients with CD, and often require surgical treatment.
1,2 Usually, enteroenteric fistulas in CD arise from a diseased segment of bowel and extend to a victim segment that is free from CD. As repeated resection is always required for recurrent disease in CD, in order to preserve as much intestine as possible,
en bloc resection of fistulas (resection of both segments) is not recommended. Instead, a more conservative procedure (resection of diseased segment and suture of the victim segment) is advocated.
3
Previous studies confirmed the conservative procedure was safe when suture repair was performed on the CD-free victim segment.
4,5,6,7,8 However, when the sutured segment was affected by CD, the risk of postoperative fistula or disease recurrence was increased.
8 Therefore, the evaluation of the victim segment is essential for the decision on whether suture repair can be performed. Preoperative endoscopy with biopsies is the most accurate method for assessment of the victim segment, but it is only possible when the fistula is accessible, as in an ileosigmoid or coloduodenal location. However, more than 20% of enteroenteric fistulas are incidental intraoperative findings.
7 For fistulas that are difficult to reach with endoscopy, intraoperative inspection (macroscopic observation and tactile assessment) remains the most feasible approach to the choice of surgical procedure. The present study aimed to determine whether intraoperative inspection alone is a reliable guide compared with preoperative endoscopy + intraoperative inspection when choosing between
en bloc resection and a conservative procedure in CD complicated by an enteroenteric fistula.
METHODS
1. Patients
Approval from the Institutional Review Board of Jinling Hospital was obtained (2015NZKY-25), and the study was performed according to the principles of the Declaration of Helsinki. Eligible patients gave written informed consent. All patients undergoing surgical treatment at the IBD center in Jinling Hospital for enteroenteric fistulas complicating CD between January 2011 and August 2016 were identified from a prospectively maintained database. When additional data were required, medical records were reviewed. Only patients receiving suture closure of the defect on the victim segment were included in this retrospective study. The diagnosis of CD was endoscopically and histologically confirmed, and the diagnosis of enteroenteric fistula was confirmed by radiographic, endoscopic, and/or intraoperative findings. The following information was collected: sex, age at surgery, disease duration, disease phenotype according to the Montreal classification, smoking history, family history, preoperative medical treatment, and initial clinical manifestation. Details of surgical procedures, diameter of defects, postoperative complications, and CD recurrence were also obtained.
Preoperative total abdominal CT was routinely performed on all patients in our center, and preoperative colonoscopy was performed on those undergoing elective intestinal resection. Gastroduodenoscopy was performed when coloduodenal fistula was suspected. Fistula, abscess or phlegmon, and a star sign on CT, fistula and pseudopolyp on endoscopy, and fistula on fluoroscopic contrast studies were considered positive findings. When fistula was diagnosed or suspected, the intestine around the fistula was evaluated using endoscopy with biopsies if possible. Patients were divided according to whether the victim segment was evaluated by preoperative endoscopy + intraoperative inspection (PI group) or by intraoperative inspection (I group). In the PI group, suture repair of the victim segment was performed only when there was no evidence of disease on both preoperative endoscopy and intraoperative inspection. In the I group, whether suture repair was performed mainly depended on intraoperative findings (no obvious macroscopic disease such as stenosis, non-indurated tissue around the fistula, no ulcers on the mesenteric side, etc.).
2. Definitions
Postoperative complications were defined as any complication occurring within 30 days after surgery. Clinical recurrence was defined as a CDAI score >150 and CRP >10 mg/L. Endoscopic recurrence was defined as a Rutgeerts score of i2 or above.
9 Surgical recurrence was defined as repeat resection for recurrent CD.
3. Surgical Technique
All operations were performed by the same team using open laparotomy. The judgement of whether the victim segment was CD-free was based on preoperative examination and intraoperative inspection in the PI group, and repair was performed only when the victim segment was confirmed normal by both preoperative endoscopy and intraoperative inspection in this group, and by intraoperative inspection alone in the I group. After the fistula was divided by finger fracture and sharp dissection, the diseased segment was resected. Stapled side-to-side anastomosis or temporary fecal diversion was carried out depending on the patient's intraoperative presentation and general condition. The defect on the victim intestine was trimmed until soft, and then closed using a double-layer submucosal continuous transverse repair with 4-0 Vicryl absorbable suture (Ethicon, Johnson and Johnson Inc., Somerset County, NJ, USA).
10 For temporary fecal diversion, delayed anastomosis was performed 3 to 6 months later. For maintenance therapy, azathioprine (AZA) was given within 2 weeks after surgery; if not tolerated, infliximab or
Tripterygium wilfordii Hook F was considered. All patients were followed by internet, telephone, or outpatient visits. Endoscopic follow-up was initiated 2 to 6 months after surgery, and then performed every 6 to 18 months. For these patients, the victim segment was assessed if accessible on endoscopic examination.
4. Statistics
All analyses were carried out using GraphPad Prism version 6 (GraphPad Software, San Diego, CA, USA). P-values <0.05 were considered significant. Categorical data were expressed as frequencies and percentages, and continuous data were expressed as mean±SD. The chi-square test was performed for group categorical data comparisons, and the t-test was used for group continuous data comparisons.
DISCUSSION
Enteroenteric fistula is a common and intractable complication of CD, and surgery is still the mainstay of treatment. The complexity of this type of fistula results from more extensive intestinal inflammation, associated abdominal mass, conjunction with the abdominal wall, or enterocutaneous fistula. As surgery is not curative for CD, 24% of patients need reoperation within 5 years.
11 Surgical treatment with
en bloc resection of fistulas may lead to the loss of a large quantity of normal intestine and will increase the risk of intestinal failure. As an internal fistula in CD is often a communication between diseased intestine and a victim intestinal segment, a more conservative procedure, with resection of only the diseased intestine and preservation of the victim segment, has been recommended for decades.
12,13 Studies have confirmed this procedure is safe in CD ileosigmoid fistulas.
The main difficulty in the conservative procedure remains reliable diagnosis of the victim segment, especially in those fistulas found incidentally at the time of operation. If the victim segment affected by CD is left in place, an immediate (postoperative fistula) or late (recurrent disease) complication can develop. Endoscopy is the most useful examination for CD detection, and should be conducted if possible. CT can provide useful information for fistulas that are hard to reach on endoscopic examination and those found intraoperatively, but is not definitive. In the present study, we reviewed our experience of intestinal repair in fistulizing CD. Sixty-five repairs (25 in duodenum, 19 in small intestine, and 21 in sigmoid colon/rectum) were performed during a 5-year period. Results indicated that intraoperative inspection (macroscopic examination and tactile assessment) alone was a reliable guide when choosing between en bloc resection and a conservative procedure, and did not increase the risk of postoperative leak at the site of repair or postoperative disease recurrence.
Preoperative diagnosis of a fistula is important, and can help in the choice of appropriate examinations for the victim segment. Clinical symptoms and diagnostic methods such as endoscopy, CT, and barium enema are useful for the detection of internal fistulas.
14,15 More than 70% of fistulas can be detected before surgery. Other than direct evidence for internal fistulas on diagnostic examination, studies have reported that a “star sign” on MRI or CT, and segmental sigmoid polyposis can also be used as diagnostic markers of enteroenteric fistulas.
15,16
The value of preoperative endoscopic assessment of victim intestinal segments has been investigated in one study. Saint-Marc et al.
8 compared 15 CD ileosigmoid fistula cases that underwent preoperative colonoscopy with 15 that did not, and found macroscopic intraoperative examination alone led to a 33% rate of incorrect evaluation of colonic involvement by CD. There was greater morbidity without preoperative colonoscopy, but the difference was not significant. This result suggested that microscopic disease may not affect outcomes in the conservative procedure. In the present study, 28 fistulas were found intraoperatively or could not be reached on endoscopic examination. The assessment of the presence of CD in victim segments mainly depended on macroscopic observation and tactile assessment, and both short- and long-term outcomes of these repairs were also satisfactory. Preoperative endoscopic assessment should be done if possible, but a decision based on intraoperative inspection alone is acceptable for fistulas found incidentally during surgery and inaccessible with endoscopy.
Although the majority of patients received preoperative optimization, the rate of temporary fecal diversion in this study was 50.8%, which was relatively high but consistent with previous reports (7.7%-51.0%).
7,17 Possible explanations are as follows. First, patients treated in our highly specialized inflammatory bowel disease center may be more complex. This was reflected in the presence of multiple fistulas, more intra-abdominal abscesses, and poor general conditions in this study cohort. Second, in order to reduce the risk of repair failure, surgeons intuitively preferred to perform a protective stoma. The incidence of postoperative complications was 29.2%, and the incidence of intra-abdominal septic complications was 10.7%. These results are superior to those reported in a meta-analysis (20.2%) of open surgery in CD,
18 but slightly higher than in a study that used similar preoperative management.
17 Our results for clinical, endoscopic, and surgical recurrence are also comparable to those reported in a previous study.
19 Postoperative AZA maintenance therapy, smoking cessation, and scheduled follow-up may contribute to the relatively low rate of recurrence.
This study has several limitations. First, because of the retrospective nature and small sample size, the results may be overestimated. Furthermore, this is a single-center study, and the surgical experience and practices may affect the results.
In conclusions, Enteroenteric fistula is a common complication of CD. When surgery is required, a conservative procedure (resection of diseased segment and suture of the victim segment) is recommended, and the preoperative evaluation of the victim segment is important for the choice of surgical procedure. For fistulas found intraoperatively and inaccessible on endoscopic examination (preoperative endoscopic evaluation of the victim segment was not possible), intraoperative inspection (macroscopic examination and tactile assessment) alone was a reliable guide when choosing between en bloc resection and a conservative procedure, and did not increase the risk of postoperative leak at the site of repair or postoperative disease recurrence.