A retrospective chart review of patients diagnosed with complex rectal or anal fistulas who underwent an EAF procedure by the Principal Investigator between January 2004 and February 2019 was done. This study was approved by the Institutional Review Board under Protocol # 2019-233.
Inclusion and Exclusion Criteria:
Patients who presented with complex rectal or anal fistulas and underwent EAF placement were included. A complex rectal or anal fistula was defined as one or more of the following: (i) fistula tract that involve at least the proximal two-thirds of the external anal sphincter (ii) involvement of any nearby organ, (iii) etiology associated with a high risk of recurrence (i.e., pelvic radiation, Crohn’s disease, etc.), (iv) recurrence after previous fistula surgery. Complex fistulas were diagnosed and initially assessed by physical examination. If fistula tract or anatomy was unclear, MRI was done to confirm the presence of complex fistula-in-ano.
Data Collection:
Patient demographic information including age, sex, race, body mass index (BMI), number and type of previous perianal surgeries, history of smoking, systemic steroid use, immunomodulator or immunosuppressive use, Inflammatory Bowel Disease (Crohn’s, Ulcerative Colitis (UC) or indeterminant colitis), Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, Coronary Artery Disease, Type II Diabetes Mellitus, Hypertension, and Chronic Kidney Disease were recorded if listed as a diagnosis within the patient’s chart. Immunomodulator or immunosuppressive use was defined as those who before or at the time of surgery received the current FDA approved agents for the treatment of Crohn’s or UC (including, mercaptopurine, azathioprine, infliximab, or any novel monoclonal antibodies), or chemotherapy for alternative cancer, or immunosuppression for a history of solid organ transplantation. The etiology of fistula-in-ano including cryptoglandular, Crohn’s disease, UC, post-obstetric fistula, radiation-induced, carcinoma, or Hidradenitis Suppurativa was noted. Additional information regarding the surgical procedure was noted including date of surgery, date of subsequent follow-up visits and date of last follow-up, presence of recurrence of symptoms post-surgery, and subsequent surgical interventions (such as diversion, fistulectomy or repeat EAF). The presence of fecal incontinence, before and after surgery, was recorded based on a non-validated questionnaire.
Outcomes:
Primary outcomes were fistula recurrence and new-onset fecal incontinence after EAF surgery. The symptoms were assessed, and the operative site was examined by the surgical team at the same hospital at 1-2 weeks post-surgery and then every 3 months until complete healing. Recurrence was defined as “the presence of an abscess or purulent drainage from the primary fistula area after at least 6 weeks of healing from EAF”. Fecal incontinence was defined as “difficulty controlling stools (soiling) or flatus during follow-up as described by the patient.”1,2
Endorectal Advancement Flap: Technical details
Preoperative and intraoperative patient preparation:
All patients received full bowel preparation prior to surgery. On the day of the surgery, a fleet or saline enema was given to the patient based on tolerability. All procedures were performed in the outpatient setting under spinal or general anesthesia. Patients that had fistulas with an anterior lying internal opening were positioned in a prone-jack-knife position, whereas those with a posterior internal opening were placed in a lithotomy position.
Description of the surgical technique:
Initial exposure of the surgical field is provided using a Park’s anal retractor, which is later exchanged for a large or medium-sized Sawyer or Hill-Ferguson retractor to decrease tension on the lateral edges during flap closure. Since local anesthetic injection around the future flap site could potentially compromise flap perfusion, local anesthetic is not administered. The rectal mucosa is dissected using needle-tip electrocautery, ensuring a flap base that is three times wider than the apex of the flap (Figure 2A & 2B). Once the flap is created, the internal opening is closed by imbricating the internal sphincter using multiple transverse interrupted 2-0 Vicryl sutures (Figure 2A & 2C). This modification not only serves to close the internal sphincter opening, but it also decreases tension on the flap during the closure. The flap is secured over the center of the defect by suturing the inferior edge of the flap with multiple interrupted 3-0 Vicryl sutures to the internal sphincter and anoderm distally. Compared to running sutures, interrupted suture placement is believed to be essential in allowing drainage of fluid and blood from underneath the flap that would otherwise collect and impair healing. The lateral edges of the flap are then closed with running 3-0 Vicryl suture, with lateral bites that measured less than 3mm (Figure 2D).
All external fistula openings and granulation tissue are debrided in a core-out fashion, and the fistula tract(s) are excised to the border of the external sphincter muscle (Figure 3A, 3B &3C). Post-operatively, patients are instructed to avoid strenuous activity and provided with non-narcotic analgesia for 7 days. Patients are followed-up in the clinic at 1-2 weeks postoperatively and approximately every 3 months thereafter until complete healing. Fiber supplements are provided to maintain regular bowel movements and avoid constipation during post-operative healing.
Statistical Analysis:
Continuous variables were reported as median with interquartile range (IQR). Categorical variables were represented as frequency with percentages. Data was analyzed for normality using the Shapiro-Wilki’s test. Student’s t-test was used to analyze normally distributed data, and Mann-Whitney U tests were used to analyze data that was not normally distributed. Categorical variables were compared using Pearson chi-squared test. Statistical analysis was performed using StataSE software (StataCorp. 2019. Stata Statistical Software: Release 16. College Station, TX: StataCorp LLC), and statistical significance was defined as P<0.05. Figures were created using Adobe Illustrator version 24.0.1