botox® (onabotulinumtoxin a) injection(s) as a treatment for carpal tunnel syndrome

Conditions: Carpal Tunnel Syndrome

Summary: this study will be a prospective double blind controlled randomized trial of ten patients diagnosed with carpal tunnel syndrome (cts). the study will be completed at offices of medical practices in arizona. patients who meet inclusion criteria will be randomly distributed into two groups: a botox® (onabotulinumtoxin a) injection group and a normal saline injection (ns) (placebo group). each group will consist of five randomly assigned individuals.

this is a pilot study, to assist with determining appropriate botox® (onabotulinumtoxin a) dosing and injection locations in patients suffering from cts. outcome measures will be obtained at follow-up at 6, 12, and 18 weeks post botox® (onabotulinumtoxin a) injection and post saline injection using the same scales and instruments at baseline, namely levine scale, jamar pinch dynamometer, edx/ncs and nmus. these measurements will be used to identify the effectiveness of botox® (onabotulinumtoxin a) in decreasing thenar muscle strength, appropriate botox® (onabotulinumtoxin a) injection dosing, and ability to decrease the inflammation, median nerve dysfunction, edema, symptoms of pain, numbness, and tingling often with associated with cts.

Eligibility criteria:
inclusion criteria: * patient history: evaluated using the levine scale for cts, a self-administered questionnaire which assesses the function and severity of cts. * physical exam: including use of jamar pinch dynamometer to quantify initial baseline strength and confirm decreased pinch strength post injection to verify effective botox® (onabotulinumtoxin a) injection. * electrodiagnostics (edx): the following criteria would establish cts through edx namely baseline electromyogram (emg) and nerve conduction studies (ncs): a) median nerve distal motor latency (dml) \>4.3ms or \>0.9ms above the ulnar nerve dml b) median distal sensory latency (dsl) to d-1 \>2.9ms or \>0.4ms above radial nerve d-1 dsl. c) median d-2 dsl \>3.7ms or \>0.4ms above ulnar nerve d-5 dsl (5). d) median mixed nerve palm-to-wrist latency (at 8cm) \>2.2ms or \>.3ms above ulnar mixed nerve palm-to-wrist latency (at 8cm). * imaging \& measurements (nmus): carpal tunnel images will be obtained in a transverse plane in both a neutral relaxed position at the level of the pisiform and longitudinally during neutral and dynamic stress testing (dst) by a a sonosite m-turbo 6-13 mhz ultrasound system or another similar system (+ 2% accuracy). measurements: transverse images of the ct will measure the median nerve cross sectional area (csa) at the level of the pisiform bone. csa measurements greater than 11 mm2 are indicative of cts. borderline csa measurements would require wrist forearm ratio (wfr) measurements to be a wfr \> 1.5. patients will need to have a csa \>11mm2, (or wfr \>1.5) and show median nerve compression during dst of at least 30% to be included. exclusion criteria: * patients with prior carpal tunnel surgery, prior history of botox® (onabotulinumtoxin a) injection * steroid injection two months prior or three months after botox® (onabotulinumtoxin a) cts injection, median nerve denervation on needle emg * major limb trauma or surgery, dysphagia * neuromuscular junction disorder (ie: myasthenia gravis or lambert-eaton syndrome) * currently pregnant or breast feeding * patients with severe cts identified by levine scale \>4, electrodiagnostics, and/or unable to meet the inclusion criteria as identified above would be excluded as participants in this study.