title: Long term effect of local corticosteroid injection for carpal tunnel syndrome: a relation with electrodiagnostic severity.
abstract: OBJECTIVE
  Carpal tunnel syndrome (CTS) is a common entrapment neuropathy. A local corticosteroid injection at the carpal tunnel inlet is often given to reduce the signs and symptoms. The long term effect of a local corticosteroid injection is not known yet. The aims of the study were to assess the long term effect of a local corticosteroid injection and the rognostic factors.
  
  
  METHODS
  Assessment of 419 consecutive patients, seen between November 2004 and November 2007 at our Neurology out-patient clinic. After confirmation of the diagnosis CTS the treating neurologist decided on the patients eligibility for a local corticosteroid injection, containing 40 mg methylprednisolone.
  
  
  RESULTS
  Local corticosteroid injection was given to 273 of the 419 patients with CTS (65%), 122 (29%) were treated surgically and 24 (6%) were treated by another therapy. Of the 273 patients long term follow-up was available for 211 (77%) patients. A beneficial effect of more than 6 months was seen in 132 patients (63%), longer than 12 months in 102 patients (48%), and longer than 18 months in 71 patients (34%). Only severity of electrodiagnostic testing was a predictor of outcome. The median time until treatment failure was 15 months for mild, 5 months for moderate and 4.5 months for severe CTS (logrank test p=0.02).
  
  
  CONCLUSIONS
  Patients with an electrodiagnostically mild CTS (i.e., abnormal comparative tests or prolonged median DSL>3.5 ms but normal median DML) are good candidates for a local steroid injection with 50% having a good long term effect for more than 15 months.
  
  
  CONCLUSIONS
  This study shows that the EMG severity of CTS is an important prognostic factor for the long term effect of a local steroid injection.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, St. Elisabeth Hospital, Tilburg, The Netherlands. l.visser@elisabeth.nl
authors.forename: Leo H
authors.initials: LH
authors.lastname: Visser
authors.forename: Quang
authors.initials: Q
authors.lastname: Ngo
authors.forename: Sascha J M
authors.initials: SJ
authors.lastname: Groeneweg
authors.forename: Geert
authors.initials: G
authors.lastname: Brekelmans
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000188:drug therapy* / Q000503:physiopathology; D004568:Electrodiagnosis / Q000379:methods*; D004576:Electromyography; D023381:Endpoint Determination; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology; D005500:Follow-Up Studies; D006225:Hand / Q000503:physiopathology; D006801:Humans; D007273:Injections, Intramuscular; D053208:Kaplan-Meier Estimate; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000627:therapeutic use; D008875:Middle Aged; D009133:Muscular Atrophy / Q000175:diagnosis / Q000209:etiology; D011379:Prognosis; D012678:Sensation Disorders / Q000175:diagnosis / Q000209:etiology; D016019:Survival Analysis
chemical_list: D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents; D008775:Methylprednisolone