H-type tracheo-oesophageal fistula is a rare anomaly contributing to 5% of congenital trachea-oesophageal fistulae. Ligation of H fistula is curative however management may be complicated by late diagnosis, variation in therapy strategy(s) including risks of damage to recurrent laryngeal nerves. Global metrics of incidence, operative methods and post-operative complications are not clearly defined. A systematic review of available case reports, case series and major reviews of H-type TOF was therefore undertaken to define and benchmark outcomes for this rare anomaly.
PubMed was searched for ALL studies reporting congenital H-type TOF during 1997 - 2018. Manuscripts were screened by title, and abstract for eligibility.
11 case series ( 5 patients or more ) with H-type fistula were identified . All except 2 reports were from single centres including 1 review article. Studies recorded an average incidence of 5%. Associated lesions included cardiac (23%), ano-rectal malformations (7%) and renal anomalies (14%). There was wide variation in preoperative localisation techniques – fluoroscopy, methylene blue injection, guide wire placement and catheterisation. The most common operation deployed is ligation through a cervical incision, yet thoracotomy, thoracoscopy and endoscopic fistula ligation are also described. Morbidity where reported included fistula recurrence (5%), leak (1%) , wound infection ( 6%) and respiratory sequelae (3%). The most commonly reported adverse complication in all studies was vocal cord palsy secondary to laryngeal nerve injury ( 20%) yet few centres routinely reported undertaking vocal cord screening post operatively
This study demonstrates that many published reports citing outcomes for H fistulae record small patient numbers. Larger cohorts and multicentre studies may help to better define 'best practice' management. Laryngeal nerve injury is a significant adverse event with H fistula operation and may be worringly underdiagnosed.