Table 1.
Characteristics of included studies of local surgical procedures (n = 10) and intersphincteric ligation (n = 8) included in the SLR
| Author, year | Country, location | Key inclusion criteria | Key exclusion criteria | Patients’ surgical experience | Sample size for CCF | Intervention for complex CCF | Follow-up (range) | Risk of bias (ROBINS-I) |
|---|---|---|---|---|---|---|---|---|
| Local surgical procedures | ||||||||
| Boenicke 2017 | Dept of General and Visceral Surgery at the Helios Univ Hosp, Wuppertal, Germany | Patients who had cryptoglandular transsphincteric (larger than 1/3 of the external sphincter involved) or suprasphincteric fistula, with previous fistulectomy with seton drainage, and were treated with advancement flap in the study institution between January 2012 and January 2015 |
1. IBD 2. High RVF |
Surgery experienced | 61 | Extrasphincteric fistula tract excised from the external opening to the intersphincteric space, followed by seton placement for 6–8 weeks, and finally advancement flap procedure (n = 66; 61 attended follow-up) | Mean 25 (12–50) months | Moderate |
| Ding 2015 | Dept of Colorectal Surgery, Colorectal Disease Center of People’s Liberation Army and Dept of Medicine Second Artillery General Hosp Beijing, China |
Consecutive consenting patients with anal fistula accessed in hospital (February 2011 to September 2013): 1. Primary cryptogenic anal fistula 2. ≥ 18 years old 3. Completion at 1-year follow-up |
1. IBD 2. RVF 3. Diabetes 4. Previous pelvic radiotherapy 5. Fecal incontinence (Wexner Incontinence Score > 7) |
Surgery experienced or naïve | 79 | Cutting seton with fistulectomy (n = 41), advancement flap (n = 38) | 1 year | Moderate |
| El-Said 2019 | The Colorectal Surgery Unit of Mansoura Univ Hosp, Mansoura, Egypt |
Primary or recurrent CAF (January 2016 to January 2018) CAF included HTF, suprasphincteric, extrasphincteric, horseshoe fistulas, and anterior fistula in female patients |
1. Intersphincteric anal fistula or low transsphincteric anal fistula involving < 30% of the external anal sphincter 2. Coexisting anal condition such as hemorrhoids and anal fissure were excluded 3. Secondary anal fistula caused by IBD, malignancy, STDs, or radiation |
Surgery experienced or naïve | 32 | Modified Parks’ technique (n = 32) | Median 12 (6–24) months | Moderate |
| Emile 2018 | Colorectal Surgery Unit of Mansoura Univ Hosp, Mansoura, Egypt | Primary cryptoglandular anal fistula admitted to colorectal surgery unit between January 2009 and January 2017 | Secondary fistula-in-ano due to traumatic conditions, IBDs, malignancy, radiation therapy, STDs, tuberculosis, or other specific etiologies | Surgery experienced or naïve | 266 had high anal fistula | Anal advancement flap (n = 9) | Median 22 (5–42) months | Moderate |
| Farag 2019 | Colorectal Unit, Cairo Univ Hosp, Cairo, Egypt |
Consecutive patients diagnosed with high CAF: high transsphincteric perianal fistulae (defined as involving > 50% of the external anal sphincter) and suprasphincteric perianal fistulae (defined as fistulae extended completely above the external anal sphincter), presenting to the study institution from March 2016 and August 2017 Age between 18 and 60 years |
1. Simple anal fistula 2. Preoperative incontinence 3. Comorbidity and chronic illness affecting healing process 4.Acute anal sepsis 5. Impaired fecal continence before operation |
Not reported | 173 | One-stage fistulectomy and reconstruction (n = 175) | 1 year | Moderate |
| Lee 2015 | The National Univ Hosp, Singapore | Underwent advancement flap procedure for high anal fistula (defined as fistula with involvement of proximal 2/3 of the internal and external sphincter muscle) of cryptoglandular origin at the study institution from June 2003 to April 2012 |
1. Concurrent RVF 2. Fistulas from Crohn’s disease 3. Fistulas from HIV 4. Incontinence or difficulty controlling solid or liquid motion or flatus prior to surgery |
Surgery experienced or naïve | 61 |
Advancement flap (n = 61), including: Endorectal advancement flap (n = 48) Anocutaneous advancement flap (n = 13) |
Median 6.5 (1–59) months | Moderate for other outcomes; serious for FI outcome |
| Litta 2019 | Proctology Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy |
1. Underwent FIPS (for either primary or recurrent, simple or CAF in the study institution between June 2006 and May 2017 2. Complex anal fistulas including: (a) high transsphincteric tract, crossing > 30% of the external anal sphincter; (b) low transsphincteric tract, only when considered at risk for postoperative fecal incontinence (anterior fistula in women, recurrent fistula, or history of fecal incontinence); and (c) suprasphincteric or extrasphincteric tracts 3. Follow-up of at least 1 year |
1. Extra- and suprasphincteric anal fistula 2. IBD 3. Traumatic-, cancer-, or radiotherapy-related anal fistula |
Not reported | 103 | FIPS (n = 103) | Mean 55.9 (12–143) months; standard deviation 30.9 months | Serious |
| Podetta 2019 | Not reported |
Group A: consecutive patients treated in the study institution by MAF for CAFa of cryptoglandular origin from January 2005 to December 2016. Group B: patients in group A presented with recurrent disease, diagnosed as CAF and operated with a second MAF Group C: patients in group B presented with a second recurrence, underwent a 3rd MAF |
1. IBD 2. RVF 3. History of perineal radiation therapy or malignancy-associated anal fistula 4. simple anal fistula in groups B and C |
Surgery experienced or naïve |
Group A: 121 Group B: 32 Group C: 6 |
MAF (n = 121) | Median 74 (8–148) months | Moderate |
| Schiano di Visconte 2018 | S. Maria dei Battuti Hosp, Conegliano, Treviso, Italy |
1. Treated with RAF or Permacol™ paste injection between September 1, 2013 and January 31, 2016 2. Primary and recurrent complex cryptoglandular anal fistulas 3. Transsphincteric fistula (tract crossing > 30% of the external anal sphincter) 4. Suprasphincteric fistula 5. Extrasphincteric fistula 6. Horseshoe fistula |
1. CD 2. Intersphincteric or low transsphincteric fistulas (involving < 30% of the sphincter complex) 3. AVF or RVF 4. Rectourethral fistulas 5. Fecal incontinence (Continence Grading Scale > 9) 6. Prior rectal anastomosis 7. Prior pelvic radiotherapy |
Surgery experienced or naïve | 52 |
Rectal advancement flap (n = 31) Permacol™ paste (n = 21) |
Median 24 months (range not reported) | Moderate |
| Visscher 2016 | A tertiary center and a private center specialized in proctology (both unnamed), authors’ affiliation is the Netherlands | Prior 3D-EAUS for cryptoglandular anal fistula between 2002 and 2012 | Non-cryptoglandular fistulas (i.e., diagnosis of IBD, hidradenitis suppurativa, tuberculosis, HIV, actinomycosis, or anal carcinoma) | Surgery experienced or naïve | 47 had high fistula |
Fistulectomy only (n = 28), fistulectomy combined with MAF (n = 19) |
Median 26 (2–118) months (includes all fistulas) | Moderate |
| Intersphincteric ligation | ||||||||
| Deimel 2016 | Not reported but authors’ affiliation is Germany | Patients with HTF who were treated with modified LIFT between October 2012 and February 2016 | CD | Surgery experienced or naïve |
n = 42 n = 40 had follow-up information |
Modified LIFT surgery (n = 42) | Mean 14.2 months | Moderate |
| El Rhaoussi 2019 | Gastroenterology and Proctology Dept, Casablanca, Morocco | Patients operated on for cryptoglandular non-specific CAF by LIFT technique at the study institution between April 2016 and October 2018 | Not reported | Surgery experienced or naïve | n = 28 | LIFT (n = 28) |
Median for healing outcome 12 weeks Mean for relapse outcome 18 months Duration not reported for incontinence outcome |
Moderate |
| Garg 2017 | Unnamed referral institute, Author’s affiliation is India |
All the consecutive patients operated in the study institution between January 2015 and July 2016 1. High cryptoglandular fistula-in-ano (involving > 1/3 of the sphincter complex as assessed on MRI scan and intraoperative examination under anesthesia) 2. Horseshoe fistula 3. Supralevator fistula |
1. Low fistula (involving < 1/3 of the sphincter complex) 2. Fistula-in-ano with CD |
Not reported | N = 61 (9 patients were excluded from analysis) | Transanal opening of intersphincteric space (TROPIS) procedure (n = 61) | Median 9 (6–21) months | Moderate |
| Lau 2020 | Royal Prince Alfred Hosp, Sydney, Australia |
1. Patients who had LIFT and BioLIFT as their sentinel definitive repair of complex fistula-in-ano during the 10-year study period (January 2009 to June 2018) 2. Patients who had previously failed fibrin glue or fibrin plug, as the anatomy, and tissue planes within the anal sphincter complexes were not disrupted by previous surgery |
Non-cryptoglandular fistulas | Surgery experienced or naïve | n = 116 |
The intervention was LIFT and/or BioLIFT procedure LIFT as the primary procedure (n = 105). LIFT was primarily performed on patients with transsphincteric fistulas with associated low resting anal sphincteric pressures. 7 out of these 105 later received BioLIFT as the subsequent intervention BioLIFT as the primary procedure (n = 11). 1 out of these 11 patients received LIFT as the subsequent intervention |
Median 36.4 (7.1–234.3) weeks | Moderate |
| Schulze 2015 | The Townsville Hosp., Townsville Day Surgery Hosp., Mater Hosp Pimlico, Australia |
1. Consecutive patients treated with LIFT for complex anorectal fistula of cryptoglandular origin between May 2008 and June 2013 2. Patients with recurrent disease 3. Patients with failed anorectal advancement flap 4. Patients previously treated for the same condition by other surgeons |
1. Simple fistulas 2. Fistulas due to non-cryptoglandular etiology such as CD, radiation, or chronic infections such as tuberculosis and chronic diarrhea |
Surgery experienced or naïve | N = 75 patients |
LIFT (n = 75) including standard LIFT (n = 72) and 2 LIFT procedures performed simultaneously for multiple tracts (n = 3) |
Mean 14.6 months (standard error of the mean 1.7 months) | Moderate |
| Sun 2019 | Unnamed Institute, authors’ affiliation is China | All patients with HTFsb who underwent LIFT procedures between September 2012 and December 2017 were included |
1. Intersphincteric, low transsphincteric, suprasphincteric fistulas or HTFs with an intersphincteric extension 2. IBD 3. Tuberculosis 4. Immunological diseases 5. Patients lost to follow-up |
Surgery experienced or naïve | N = 70 patients (71 LIFT procedures) |
LIFT without prior loose setons (n = 70) Total number of LIFT procedures n = 71 |
Median 16.5 (4.5–68) months | Moderate |
| Wen 2018 | Suzhou Affiliated Hosp. of Nanjing Univ of Chinese Med |
1. > 18 years old 2. Complex cryptoglandular anal fistula with newly diagnosed fistula-in-ano 3. No significant abnormalities of external and internal sphincter in anorectal pressure measurement 4. Patient wants to be submitted to LIFT surgery and has signed the informed consent before the operation 5. Treated with modified LIFT in study institution between January 2013 and December 2016 |
1. Patient refused LIFT surgery and chose other surgical treatment 2. “No Crohn’s disease” 3. Another inflammatory bowel disease or malignancy |
Surgery naïve | N = 62 | Modified LIFT (n = 62) | Median 24.5 (12–51) months | Moderate |
| Ye 2015 | Dept of Colorectal Surgery, the First Affiliated Hospital, Zhejiang Univ, Hangzhou, China; Dept of General Surgery of the People’s Hospital of Deqing County; Huzhou, China |
Consecutive patients who underwent the modified ligation of the intersphincteric fistula tract (mLIFT) procedure in the study institution from June 2012 to March 2013 Patients who were deemed candidates for the mLIFT procedure were those who had an HTF, i.e., endoanal ultrasonic or MRI showed the tract crossing the external sphincter by 30% or more, and fistulotomy would place them at a high risk of incontinence |
1. Low transsphincteric fistulas 2. Suprasphincteric fistulas 3. Extrasphincteric fistulas 4. Patients with a rectovaginal fistula 5. Fistulae due to CD, tuberculosis, or acquired immune deficiency syndrome |
Not reported | n = 43 patients (4 patients were lost to follow-up) |
mLIFT (n = 39) Delayed mLIFT procedure (n = 4) |
Median 15 (12–24) months | Moderate |
3D-EAUS 3D endoanal ultrasound, AVF anovaginal fistula, CAF complex anal fistula, CCF complex cryptoglandular fistula, CD Crohn’s disease, HTF high transsphincteric fistula, HIV human immunodeficiency virus, IBD inflammatory bowel disease, FIPS fistulectomy and primary sphincteroplasty, LIFT ligation of intersphincteric fistula tract, MAF mucosal advancement flap, RAF rectal advancement flap, RVF rectovaginal fistula, STD sexually transmitted disease
aAnal fistulas are anatomically defined according to Parks’ classification. All high transsphincteric, suprasphincteric, and intersphincteric crossing > 30% of the external sphincter or horseshoe-shaped anal fistulas were classified as complex
bFistulas were classified according to Parks’ classification. An HTF was defined as the tract traversing above the subcutaneous external anal sphincter