Frequency and diagnostic yield of CRPS-I in TBI: a 12-year retrospective cohort study at a Level I trauma center

Objective To investigate the frequency and diagnostic yield of Complex Regional Pain Syndrome Type I (CRPS-I) among traumatic brain injury (TBI) patients and to identify objective clinical triggers and associated factors.Design A 12-year retrospective cohort study.Setting A Level I trauma center in South Korea.Participants 5,773 TBI patients admitted between January 2011 and December 2022.Main outcome measures CRPS-I was diagnosed using Budapest research criteria supported by three-phase bone scintigraphy (TPBS) in clinically suspected patients. We evaluated CRPS-I frequency, diagnostic yield, and associated factors via univariate analysis.Results Of 5,773 patients, 123 underwent TPBS for clinical suspicion, confirming 24 CRPS-I cases. The observed frequency was 0.42%, with a 19.5% (24/123) diagnostic yield among suspected patients. Edema and motor limitation were present in confirmed cases. Among clinically suspected patients, those with confirmed CRPS-I were older than those without confirmed CRPS-I (63.3 vs. 53.9 years, p = 0.028), whereas global injury severity (GCS, ISS) showed no association.Conclusions The 0.42% frequency underestimates true CRPS-I prevalence due to selective testing. However, a 19.5% diagnostic yield reveals significant under-recognition in cognitively impaired patients when relying on symptom-based criteria. Edema and motor limitation may serve as practical triggers for adjunctive TPBS evaluation in non-communicative survivors.