Predictors of leech therapy failure in revascularized and replanted digits

Venous congestion is a common phenomenon following digital revascularization and replantation. Leech therapy allows for venous outflow while angiogenesis and neovascularization take place. The aim of this study is to evaluate the efficacy of leech therapy in the revascularized and replanted digits and determine risk factors for unsuccessful salvage.

A retrospective review was performed to identify all patients with complete or incomplete digital amputations at an academic Level 1 Trauma Center who underwent digital replantation or revascularization from January 2005 to December 2020. Amputations proximal to the palmar arch as well as revascularizations that showed any degree of perfusion on preoperative assessment were excluded. Leech therapy was initiated as soon as any signs of venous congestion appeared and was titrated to clinical effect. Patient demographics, medical history, injury mechanism, extent and level, operative details, leech therapy details, number of blood transfusions, hospitalization length, as well as the digit's ultimate survival data were collected.

Of the 159 patients who underwent 213 digital revascularizations (n ​= ​135) and replantations (n ​= ​78), venous congestion requiring leech therapy developed in 27 digits in the revascularization group and in 26 in the replantation group. Of the digits that were leeched, 15 failed in the revascularization group (56 ​% failure rate) and 17 failed in the replantation group (65 ​% failure rate). Avulsion mechanism of injury and presence of a circumferential laceration were significantly associated with rate of failure in the revascularization cohort (p ​< ​0.01). Proximal level of injury was significantly associated with rate of failure in the replantation group (p ​< ​0.01).

Leech therapy has limited efficacy in avulsed or more proximally injured digits. These data can aid in determining the prognosis of a digit with venous congestion after revascularization and replantation.