Table 2.

Selected outcomes of local surgical procedures for complex cryptoglandular fistulas

Author, year	Exposure groups (patients with CCF only)	Key outcome definitions	Healing/success	Recurrence/failure	Fecal incontinence	Pain
Anal flap (n = 6)
Boenicke 2017	Advancement flap, n = 61	Primary healing: complete wound healing in combination with the absence of any symptoms like pain, bleeding, or secretion and inconspicuous transanal ultrasound findings at 6-month follow-up Fistula recurrence: a fistula or an abscess occurring after initial healing Wexner used to assess fecal incontinence Pain scale not defined	3 months: primary healing 80.3%a (49/61) 6 months: primary healing 86.9%a (53/61)	Recurrence 4.9%a (3/61) Overall therapy failure (including 8 patients with persistent wound secretion at 6 months, and 3 recurrent fistulas occurring at 9, 13, and 15 months) 18% (11/61) after a mean follow-up period of 25 months	Wexner Scale of Incontinence In all patients: 1. Preoperatively (mean ± SD) 0.37 ± 0.91 points 2. At 6-month follow-up 0.46 ± 0.97 points. (p = 0.34) In the success group (n = 50): 1. Preoperatively (mean ± SD) 0.34 ± 0.90 points 2. At 6-month follow-up 0.38 ± 0.83 points. (p = 0.59) In the failure group (n = 11): 1. Preoperatively (mean ± SD) 0.4 ± 0.92 points 2. At 6-month follow-up 1.0 ± 1.44 points. (p = 0.14) There were no significant differences compared to the success group (p = 0.07)	No scale reported 8.1% (5/61) patients suffered from postoperative stronger pain that was self-limiting and responsive to analgesics
Ding 2015	Advancement flap, n = 38	Recurrence of fistula at 1 year (recurrence was not defined) Wexner used to assess fecal incontinence	Not reported	Recurrence at 1-year follow-up 13.2%a (5/38)	Not reported by surgery type	Not reported
Emile 2018	Anal advancement flap, n = 9	Recurrence: clinical occurrence of the fistula after recovery of the surgical wound, occurring within 1 year after the procedure	Not reported	Recurrence 44.4% (4/9) Disruption of flap: Total 55.5% (5/9)	Not reported by surgery type	Not reported
Lee 2015	Advancement flap, n = 61, including: Endorectal advancement flap, n = 48 Anocutaneous advancement flap, n = 13	Healing/success is not defined Recurrence: persistent or new discharge, or any additional perianal fistula at the site of primary repair Wexner used to assess fecal incontinence	Successful flaps in all patients: 86.9% (53/61); among these 53 patients, 92.5% (49/53) had uneventful healing and 7.5% (4/53) had delayed healing 50.0%a (4/8) of the 8 failed patients underwent subsequent surgery; among them, 1 had a successful LIFT	Failed flaps/failure rate (also called “recurrence”) in all patients 13.1% (8/61)	Among the 53 patients who had a successful outcome, 3 died from unrelated causes. In the remaining 50 patients, only 54.0%a (27/50) were contacted via telephone interview to assess their continence status using the Wexner Score of 0, 77.8% (21/27) Score 1–5, 14.8% (4/27); they only complained of mild disturbances to their life and the predominant symptom was infrequent suboptimal flatus control Score 11–13, 7.4% (2/27); both complained of inability to control even solid stools and frequent symptoms that affect their lifestyle	Not reported
Podetta 2019	Group A MAF, n = 121 Group B MAFs, n = 32 Group C MAFs, n = 6	Success rate and recurrence not defined Functional status (incontinence) was evaluated by Miller score system	1. Median time between the 1st and 2nd MAF 8 months (range 3–24 months) 2. Success rate after the 2nd MAF 78.1% (numbers for calculation not reported) 3. Median time between the 2nd and 3rd MAF 9.3 months (SD 5.8), with 83% of patients recurring in less than 1 year 4. Success rate after the 3rd MAF 100% (numbers for calculation not reported)	1. Among complex anal fistula patients who underwent 1st mucosal advancement flap:  Any recurrence 33.9%a (41/121), including   26.4%a (32/121) recurrences as complex anal fistulas (this is group B)   7.4%a (9/121) recurrence as simple anal fistula 2. Among complex anal fistula patients who underwent 2nd mucosal advancement flap (group B):  Any recurrence 21.9%a (7/32), including   18.8%a (6/32) recurrences as complex anal fistulas (this is group C)   3.1%a (1/32) recurrence as simple anal fistula 3. 53.1% (17/32) patients in group B had the first recurrence during the first postoperative year 4. 83.3% (5/6) patients in group C had the first recurrence during the first postoperative year	Functional status (incontinence) was evaluated by Miller score system proposed by Miller et al. in 1988. Self-reported fecal incontinence Group A (not reported) Group B At 3 months follow-up:  1 patient mentioned some gas incontinence scored at 2  1 patient presented a rare liquid stools leakage scored at 4 After MAF for recurrent anal fistula:  Postoperative control showed unchanged degree of incontinence for both cases Group C After the 1st MAF:  1 patient suffered from rare gas incontinence scored at 1 After the 2nd and 3rd MAF:  Incontinence score did not change in that patient	Not reported
Schiano di Visconte 2018	RAF group, n = 31	Healing: the complete reepithelization of the external opening, closure of the internal opening, and clinical absence of any drainage through the external or internal opening at 6 months postoperatively Recurrence: redischarge after complete healing at any point during observation Continence disorders (CGS ≤ 4) were defined in as the inadvertent escape of flatus or partial soiling of undergarments with liquid stool Fecal incontinence was defined as CGS ≥ 5 NRS used for pain, where 1 indicated no pain, and 10 indicated the worst pain imaginable	1-year postoperative overall success rate 65% (20/31) 2-year disease-free survival/healing rate 65% (20/31) Outcomes among the patients with operative failures who underwent subsequent surgeries:  After RAF failure, fistula closure was achieved in 80.0%a (4/5) patients who underwent subsequent surgeries Outcome after recurrences  In RAF group, 50.0%a (3/6) of the 6 recurrent patients developed recurrence again after redo surgery and underwent a new operation (Note: surgery not identified). 100%a (3/3) were successful	Recurrence rates at a median follow-up of 24 months 35% (11/31) Operative failure 16% (5/31); 3 of the 5 failures had flap disruption during the 1st week During the follow-up period, after excluding patients with operative failures, recurrence rate is 19% (6/31); 5 of the 6 recurrences occurred during the first 3 months postoperatively	CGS Preoperatively  CGS 1.6 ± 1.6, 1 (0–6)b  Continence disorders 3% (1/31)  Fecal incontinence 0% (0/31) 3 months postoperatively  CGS 3.2 ± 2.7, 3 (0–8)b  Continence disorders 16% (5/31)  Fecal incontinence 16% (5/31) p value  CGS 0.000  Continence 0.004	NRS where 1 indicated no pain, and 10 indicated the worst pain imaginable  Preop 1.4 ± 0.6, 1 (1–3)b 3-month postop 1.2 ± 0.5, 1 (1–3)b Pain (NRS) p value 0.248
Fistulectomy (n = 3)
Ding 2015	Fistulectomy, n = 41	Recurrence of fistula at 1 year (recurrence was not defined)	Not reported	Recurrence at 1-year follow-up 22.0%a (9/41)	Not reported by surgery	Not reported
Farag 2019	One-stage fistulectomy and reconstruction, n = 173	Wound healing was not defined Recurrence of fistula was assessed after 1 year by clinical examination and MRI	Delayed healing (more than 8 weeks) 1.7%a (3/173) Healing rate in the total population 100%a; except for the 3 patients with delayed healing, the rest of the patients had average time of wound healing around 3–4 weeks Note: The authors did not report 100% explicitly	Recurrence rate after 1 year 8.1%a (14/173)	Not reported for patients with complex cryptoglandular fistula	Not reported
Visscher 2016	Fistulectomy only, n = 28	Recurrence: a persisting fistula requiring further surgery, or a new fistula seen during follow-up after apparent initial healing	Not reported	Recurrence rate 61% Recurrence rate by follow-up time:  12 months 42%  24 months 56%  36 months 59% Note: Authors provided percentages only (no n’s or denominators)	Not reported	Not reported
Fistulotomy and primary sphincteroplasty FIPS (n = 1)
Litta 2019	FIPS, n = 103	Healing: the absence of drainage or abscess formation, fistula closure, and complete wound healing Wexner used to assess fecal incontinence, soiling, pad use Pain scale not defined	Healing rate after a mean follow-up of 55.9 ± 30.9 (range 12–143) months 93.2% (96/103)	Not reported for complex CF	Wexner Postoperative continence impairment 18.4% (19/103)	No patients developed postoperative intractable pain
Modified Parks’ technique (n = 1)
El-Said 2019	n = 32	Healing: measured at 6 months postoperatively Recurrence: clinical occurrence of the fistula after recovery of the surgical wound, occurring within 1 year after the original procedure of anal fistula Persistence: nonhealing and persistence of surgical wound for at least 3 months after surgery Wexner to assess fecal incontinence Pain assessed using Short Form-36 Health Survey, version 2	Initial healing 93.8%a Subsequent healing 100%a Average time to complete healing 6.72 ± 1 (range 5–9) week Among the 2 patients with recurrent fistulas who were subsequently treated with draining seton, 100% (2/2) achieved complete healing after 3 months postoperatively with no recurrence on further follow-up	Recurrence 6.3% (2/32) patients who had horseshoe fistula with supralevator extension Persistence 0%	Wexner Fecal incontinence was evaluated before and after the surgery; specific time period not specified Preoperative median Wexner score 0 (range 0–17); Postoperative median Wexner score 0 (range 0–17) 3.1%a (1/32) patient had postoperative new-onset minor FI (Wexner score = 3) 6.3% (2/32) patients were preoperative incontinent:  Post-hemorrhoidectomy fecal incontinence with Wexner score of 17, n = 1  Post-fistulectomy fecal incontinence with Wexner score of 12, n = 1 The 2 patients who had FI prior to surgery maintained their continence state after the surgery	Bodily pain at 6 months after surgery was assessed by Short Form-36 Health Survey, version 2:  Before surgery 37.5 ± 9.3  After surgery 65.1 ± 7.2

CCF complex cryptoglandular fistula, CGS Continence Grading Scale,  FI fecal incontinence, FIPS fistulotomy and primary sphincteroplasty, LIFT ligation of intersphincteric fistula tract, MAF mucosal anal flap, NRS Numeric Rating Scale, RAF rectal advancement flap

^aCalculated value

^bMean ± standard deviation, median (range)