Real-World Complication Profiles of Fully and Semi-Implanted Intrathecal Drug Delivery Systems for Cancer Pain: A Large Single-Center Chinese Cohort.

introductionIntrathecal drug delivery systems (IDDS) are used for selected patients with refractory cancer pain. Fully implanted and semi-implanted systems differ in implantation pathway, maintenance requirements, external component exposure, and tissue-device interaction. This study aimed to describe real-world complication profiles of these two IDDS models in a large single-center Chinese cohort.

methodsThis retrospective registry-based cohort study included 409 patients with advanced cancer who underwent initial IDDS implantation at Sichuan Cancer Hospital between 1 January 2023, and 31 December 2025. Complications were classified into level I categories and level II subtypes. Each level II complication subtype was counted once per affected patient. Frequencies were reported as counts, patient-level proportions using the device group as denominator, and event-level proportions using recorded complication events as denominator. Because detailed baseline characteristics, standardized follow-up durations, mortality timing, event timing, and paired efficacy outcomes were not systematically available, analyses were descriptive and hypothesis-generating.

resultsAmong 409 patients, 38 received fully implanted systems and 371 received semi-implanted systems. A total of 101 complications were recorded: 10 in the fully implanted group and 91 in the semi-implanted group. In the semi-implanted group, postdural puncture headache occurred in 38 patients (10.2% of 371; 41.8% of 91 events), cerebrospinal fluid leak in 22 patients (5.9%; 24.2%), and catheter blockage in 17 patients (4.6%; 18.7%). In the fully implanted group, skin erosion occurred in four patients (10.5% of 38; 40.0% of 10 events), and inadequate analgesia occurred in two patients (5.3%; 20.0%). Findings in the fully implanted group were based on single-digit subtype counts and should not be interpreted as stable comparative risk estimates.

conclusionsFully implanted and semi-implanted IDDS showed different recorded complication profiles in this real-world Chinese cohort. Semi-implanted systems were characterized mainly by puncture-related and catheter-pathway events, whereas fully implanted systems showed tissue-integrity and treatment-adaptation events among the small number of recorded complications. These findings support individualized device selection but cannot establish device superiority or time-dependent risk because baseline, follow-up, mortality, event-timing, and efficacy data were incomplete.