Community-based referrals for electrodiagnostic studies in patients with possible carpal tunnel syndrome: what is the diagnosis?
OBJECTIVE
To determine what proportion of patients referred with a clinical suspicion of carpal tunnel syndrome (CTS) have negative electrodiagnostic studies and identify their clinical diagnoses and to identify clinical features that predict the outcome of electrodiagnostic testing in patients referred with suspected CTS.


METHODS
Retrospective review of patients consecutively referred to the electrodiagnostic center with suspected CTS over a 1-year period.


METHODS
Community-based electrodiagnostic center.


METHODS
Three hundred forty-eight patients with suspected CTS.


METHODS
Not applicable.


METHODS
The diagnosis of CTS was based on the electrodiagnostic findings.


RESULTS
Of the 348 patients enrolled, 179 (51.4%) had electrodiagnostic studies that were inconsistent with a diagnosis of CTS. Twenty-seven patients (15.1%) had other electrodiagnostic abnormalities (eg, ulnar neuropathy, cervical radiculopathy), whereas the remaining 152 (84.9%) patients had studies within normal limits. Seventy-one patients (46.7%) with normal studies were diagnosed with musculoskeletal disorders, with myofascial pain and musculotendinous strain being most common. By using a multiple logistic regression model, clinical variables that may predict the outcome of electrodiagnostic testing for CTS included gender, duration of symptoms, nocturnal symptoms, sensory symptoms, wrist pain, neck pain, pinprick sensation, abductor pollicis brevis strength, and thenar bulk.


CONCLUSIONS
Many patients referred to an electrodiagnostic laboratory with a clinical suspicion of CTS have other diagnoses, most commonly musculoskeletal disorders. Because these various conditions may be mistaken for CTS, the electrodiagnostic evaluation is therefore an important diagnostic tool. Although traditional clinical findings including Tinel and Phalen sign were found to have limited clinical use, further validation of the groups of positive and negative clinical features may potentially enable the referring physician to identify more accurately patients who would benefit most from electrodiagnostic testing.
Lo
Julian K
JK
Department of Physical Medicine and Rehabilitation, West Park Health Care Centre, University of Toronto, Toronto, Canada.
Finestone
Hillel M
HM
Gilbert
Ken
K
Woodbury
M Gail
MG
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D003151:Community Health Centers; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D012017:Referral and Consultation; D012189:Retrospective Studies