Biomechanical properties of the brachioradialis muscle: Implications for surgical tendon transfer.
نویسندگان
چکیده
PURPOSE To understand the mechanical properties of the brachioradialis (BR) muscle and to use this information to simulate a BR-to-flexor pollicis longus (FPL) tendon transfer for restoration of lateral pinch. METHODS The BR mechanical properties were measured intraoperatively. Passive elastic properties were measured by elongating BR muscles at constant velocity while they were attached directly to a dual-mode servomotor. Sarcomere length was measured intraoperatively and in situ by laser diffraction with the elbow fully extended. Then both the mechanical and structural properties were programmed into a surgical simulator to test the hand surgeon's decision making when tensioning muscles in a simulated BR-to-FPL tendon transfer. RESULTS Passive mechanical BR properties were highly nonlinear. Under slack conditions sarcomere length (mean +/- standard deviation) was 2.81 +/- 0.10 microm (n = 4), corresponding to an active force of 93% maximum. Sarcomere length of the BR measured in situ with the elbow fully extended and the forearm in neutral rotation was 3.90 +/- 0.27 microm (n = 8), corresponding to an active force of only 23% maximum. Surgeons, who tensioned the BR for transfer into the FPL using only tactile feedback from the surgical simulator, attached the muscle at a passive tension of 5.87 +/- 0.97 N, which corresponded to a sarcomere length of 3.84 microm and an active muscle force of 27% maximum. Passive BR tension when both tactile and visual information were provided to the surgeon was significantly lower (2.42 +/- 0.72 N), corresponding to a sarcomere length of 3.56 mum and a much higher active muscle force of 45% maximum. CONCLUSIONS When these data were used to model pretransfer and posttransfer function dramatic differences in predicted function were obtained depending on the tensioning protocol chosen. This emphasizes the point that the decision-making process used during muscle tensioning has a profound effect on the functional outcome of the transfer.
منابع مشابه
Variability in surgical technique for brachioradialis tendon transfer. Evidence and implications.
BACKGROUND Transfer of the tendon of the brachioradialis muscle to the tendon of the flexor pollicis longus restores lateral pinch function after cervical spinal cord injury. However, the outcomes of the procedure are unpredictable, and the reasons for this are not understood. The purpose of this study was to document the degree of variability observed in the performance of this tendon transfer...
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Biomechanical simulations of tendon transfers performed following tetraplegia suggest that surgical tensioning influences clinical outcomes. However, previous studies have focused on the biomechanical properties of only the transferred muscle. We developed simulations of the tetraplegic upper limb following transfer of the brachioradialis (BR) to the flexor pollicis longus (FPL) to examine the ...
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عنوان ژورنال:
- The Journal of hand surgery
دوره 30 2 شماره
صفحات -
تاریخ انتشار 2005