Biomechanical Analysis on Functional Outcome Evaluation in Patients with Brachial Plexus Injury

Abstract

Background & Purpose: Adult brachial plexus injuries (BPI) are devastating and mostly caused by the high energy trauma but few studies investigated the quantitative outcomes of traumatic BPI patients Therefore the specific aims of the current study were (1) to evaluate the quantitative strength and training effects in upper arm type BPI patients after double nerve transfer and (2) to evaluate the kinematics results of joint motion and circumduction task in upper and total arm type BPI patients Methods: There were 18 upper arm type (C5-C6 or C5-C7) BPI patients after double nerve transfer recruited for the first purpose After the first evaluation patients had a grip power training for 6-8 months The quantitative strength was measured by the handheld dynamometer (HHD) For the second purpose 12 upper arm and 4 total arm type BPI patients after reconstruction were recruited The kinematics values were collected by the PTI motion capture system The orientation of limb segments in the space were used to describe the movement patterns and the origin of coordinated system was set at shoulder joint center The motion range movement velocity and the area drawn by the circumduction task were calculated for further comparison Results: The quantitative strength values between the C5-C6 and C5-C7 BPI patients were significantly different even though both groups had similar BMRC scores After the grip power training patients showed the positive correlation between the changes of elbow flexion strength and grip power In the results of kinematics significant differences of yaw angle between both arms were found at abduction 75°and abduction 90° The average yaw angles at the maximum elbow flexion represented that patients combined internal rotation with elbow flexion while moving the involved arm Patients in total type BPI had less motion range and velocity than those in upper type BPI and the yaw angles during shoulder flexion and scapular flexion were different between the two groups The area drawn by the circumduction task was projected to the sagittal plane and divided into four sections The ratios of posterior/anterior and superior/inferior for the involved arm were less than the non-involved arm The ratios of posterior/anterior and superior/inferior area in total arm type BPI were significantly lower than that of the upper type BPI Discussion & Conclusion: The different outcomes between C5-C6 and C5-C7 BPI patients appeared in muscles responding to hand grip wrist extension and sagittal movements in shoulder and elbow joints In the kinematics the differences between total and upper type BPI were found in the range and mean velocity of shoulder elevation while there were no significant differences in the elbow flexion The kinematics of the scapula is an important factor to affect the movements in BPI patients

Date of Award	2014 Aug 27
Original language	English
Supervisor	Fong-chin Su (Supervisor)