Use of ultrasound in needle placement in intercostal muscles: a method for increased accuracy in cadavers.

OBJECTIVE: To validate the use of ultrasound technology for the positioning and leveling of intercostal needle placement. DESIGN: Double-blinded experimental study. SETTING: An anatomy laboratory. PARTICIPANTS: Two board-certified physical medicine and rehabilitation physicians, 2 first-year medical students, 1 anatomist, and 8 cadavers. INTERVENTIONS: Four unfixed cadavers were used for unguided needle placement, and 3 unfixed and 1 partially fixed cadavers were used for ultrasound-guided needle placement. Ultrasound-guided needle placement was then confirmed with computed tomography and blind dissection. MAIN OUTCOME MEASURE: The accuracy of needle placement. RESULTS: The unguided study showed needle placement in an intercostal muscle 89% of the time, but in only 15.4% of the time was the correct level sampled. In the 96 needle placements completed, the unguided needle placements had an accuracy of 8.3%, while ultrasound-guided needle placements had an accuracy of 93% (χ(2) with P<.005). CONCLUSIONS: Ultrasound guidance dramatically increases needle placement accuracy for intercostal nerve blocks and intercostal muscle sampling for electromyography.

Use of hand diagrams in screening for ulnar neuropathy: comparison with electrodiagnostic studies.

INTRODUCTION: The objective of this study was to determine whether a hand diagram could be used to predict ulnar mononeuropathy. METHODS: This was a prospective study of 117 consecutive patients referred for hand symptoms. Each subject filled out a hand diagram of symptoms and had median and ulnar sensory and motor nerve conduction studies, including ulnar conduction across the elbow. RESULTS: The best model for predicting an ulnar mononeuropathy included hand diagram scores of definite or possible. The model had a sensitivity of 50% and specificity of 93% with an ROC area of 0.90. CONCLUSIONS: The ulnar hand diagram scoring system can be useful as a screening tool in the electrodiagnostic laboratory or for epidemiologic studies.