Correlation between the combined sensory index and clinical outcome after carpal tunnel decompression: a retrospective review.

The combined sensory index (CSI) is a useful electrodiagnostic tool, but it was not known if the CSI can be correlated with clinical outcome following carpal tunnel decompression. The objective of this study was to examine the association between the CSI and symptom relief from pain and parasthesiae following surgical intervention. Retrospective chart review was performed on 272 patients, diagnosed with carpal tunnel syndrome by electrodiagnostic criteria, who proceeded to undergo open or endoscopic carpal tunnel release with postoperative follow-up at an academic medical center between 1996 and 2006. The CSI demonstrated statistical significance (P = 0.03) for correlation with resolution of pain and parasthesiae following carpal tunnel decompression. Patients with a CSI of 2.5-4.6 had the best prognosis for resolution of pain and parasthesiae following surgical intervention. Median compound muscle action potential (CMAP) amplitude and median motor latency were also associated with resolution of parasthesiae, but not pain. The CSI effectively establishes correlation with clinical outcomes following surgical intervention for carpal tunnel syndrome, and thus a range of optimal outcomes (CSI between 2.5 and 4.6) can also be established.