Abstract Background There is still controversy over the usefulness of seton placement prior to the ligation of the intersphincteric fistula tract (LIFT) surgery in the management of anal fistula. Objective To evaluate the impact of preoperative seton placement on the outcomes of LIFT surgery for the management of fistula-in-ano. Design systematic review and meta-analysis. Data Sources A search was performed on the MEDLINE (PubMed), EMBASE, Scopus, Web of Science, Cochrane Library and Google Scholar databases. Study Selection Original studies without language restriction reporting the primary healing rates with and without seton placement as a bridge to definitive LIFT surgery were included. Intervention The intervention assessed was the LIFT with and without prior seton placement. Main Outcome Measures The main outcome was defined as the primary healing rate with and without the use of seton as a bridge to definitive LIFT surgery. Results Ten studiesmet the criteria for systematic review, all retrospective,with a pooled study population of 772 patients. There were no significant differences in the percentages of recurrence between patients with and without seton placement (odds ratio [OR] 1.02; 95% confidence interval [CI] 0.73-1.43: p=0.35). The I2 value was 9%, which shows the homogeneity of the results among the analyzed studies. The 10 included studies demonstrated a weighted average overall recurrence of 38% (interquartile range [IQR] 27-42.7%), recurrence with the use of setonwas 40%(IQR26.6-51.2%), and without its use, the recurrence rate was 51.3% (IQR 31.3-51.3%) Limitations The levels of evidence found in the available literature were relatively fair, as indicated after qualitative evaluation using the Newcastle-Ottawa scale and the Attitude Heading Reference System (AHRS) evidence levels. Conclusions Our meta-analysis suggests that the placement of seton as a bridge treatment prior to LIFT surgery does not significantly improve long-term anal fistula healing outcomes. Ligation of the intersphincteric fistula tract surgery can be performed safely and effectively with no previous seton placement. International prospective register of systematic reviews-PROSPERO registration number: CDR42020149173.

RESUMO Objetivo: O tratamento da fístula anal persistente é um grande desafio para os cirurgiões, com risco de recorrência adicional e potencial comprometimento da continência. Os autores apresentam um tratamento não cirúrgico baseado na irrigação com solução de nitrato de prata a 1%. Métodos: Este foi um estudo prospectivo incluindo pacientes com fístula anal persistente após a cirurgia que foram tratados com irrigação com solução de nitrato de prata a 1% entre maio de 2015 e março de 2017. Pacientes com evidência de abscesso, presença de mais de uma abertura externa e aqueles com doença inflamatória intestinal foram excluídos. Usando um cateter, instilou-se 3 a 5 cc. de solução de nitrato de prata a 1%. O procedimento foi repetido semanalmente, em um máximo de sete sessões por paciente. Resultados: Um total de 18 pacientes (13 homens, 72,2%) com idade mediana de 48 anos (IQR 41-55) foram tratados com solução de nitrato de prata a 1%. Uma mediana de cinco sessões por paciente foi realizada (IQR 3-6). A mediana do período de acompanhamento foi de 18 meses (IQR 9-25). Após o período descrito, oito pacientes (44,4%) apresentaram resolução completa da fístula, dois pacientes (11,2%) foram classificados como cicatrização parcial e em oito pacientes (44,4%) o tratamento falhou. Seis pacientes apresentaram dor autolimitada durante a instilação, que persistiu por até 24 horas em dois deles. Conclusões: O tratamento com solução de nitrato de prata a 1% é um procedimento minimamente invasivo, com perfil de segurança favorável, que pode ser realizado em regime ambulatorial, atingindo taxa de cura completa de 44,4%. Portanto, este método deve ser considerado para o tratamento da fístula anal recorrente ou persistente.

ABSTRACT Purpose: Treatment of persistent anal fistula implies a major challenge for surgeons, with risk of additional recurrence and potential continence impairment. We present a non-surgical treatment based on irrigation with silver nitrate 1% solution. Methods: This is a prospective study including patients with persistent anal fistula after surgery, who were treated with silver nitrate 1% solution irrigation from May 2015 to March 2017. Patients with evidence of abscess, presence of >1 external opening and those with bowel inflammatory disease were excluded. 3-5 cc of silver nitrate 1% solution were instilled through a catheter. The procedure was repeated on a weekly basis, conducting a maximum of 7 sessions per patient. Results: 18 patients (13 male, 72.2%) with a median age of 48 years old (IQR 41-55) were treated using silver nitrate 1% solution. A median of 5 sessions per patient was performed (IQR 3-6). The median follow-up period was 18 months (IQR 9-25). After the described period 8 patients' (44.4%) presented complete resolution of the fistula, 2 patients' (11.2%) were classified as partial healing and in 8 patients' (44.4%) the treatment was considered to fail. 6 patients' experienced self-limited pain during instillation, with persistence up to 24 h in 2 of them. Conclusions: Treatment with silver nitrate 1% solution is a minimally invasive procedure, with a favourable safety profile, that can be performed in an outpatients' basis achieving a complete healing rate of 44.4%. Therefore, this method should be considered for the treatment of recurrent or persistent anal fistula.