Upper Antero-Medial Thigh as an Alternative Site for Implantation of Intrathecal Pumps: A Case Series

Abstract

Neuraxial drug delivery via intrathecal drug delivery systems (IDDS) is becoming an increasingly common mode of treating intractable cancer-related pain, chronic pain, or severe spasticity. An implanted infusion pump delivers medication into the intrathecal (subarachnoid) space via a thin catheter. These pumps are commonly placed in the anterior abdominal wall. Certain conditions may render it difficult or unsafe for an IDDS to be implanted at the traditional site; thus, alternative sites have been explored. We report on the use of the upper antero-medial thigh as a safe alternative site for this purpose. Nine patients between 22 and 69 years of age underwent placement of an IDDS infusion pump in the upper antero-medial aspect of one thigh. In each patient, the anterior abdominal wall was precluded for implantation due to various reasons, such as extensive abdominal scar tissue from previous surgeries, placement of feeding tubes and ostomies, large ventral hernia or metastatic masses protruding from the abdomen. Nine patients, with ages ranging from 22 to 69 years old, had IDDS implantation in the upper thigh. The first patient experienced wound dehiscence (antero-lateral location) and after explantation, another pump was placed successfully in the opposite thigh (antero-medial location). One patient has had pump replacement due to end-of-battery life. She also needed an unrelated catheter revision. Seven patients have expired from their disease progression after living for an average of 142.7 days (range 50 days to 354 days) while two patients continue to experience relief from pain and spasticity years later (see Table 1). No neurovascular damage, infections, or other complications occurred in our series. The upper antero-medial thigh is a safe alternative to the anterior abdominal wall for implantation of an IDDS.