Lip reconstruction using a functioning serratus anterior free flap: preliminary study.

Reconstructive surgery to the lips requires the replacement of defective tissues with similarly functioning tissues. While non-dynamic free tissue transfers provide adequate lower lip reconstruction, improved benefits may be obtained with innervated free muscle flaps. This study reports the use of innervated serratus anterior muscle free flaps for lip reconstruction in five patients. All patients had squamous cell carcinoma of either the upper or lower lip. After resection of the tumours, the resultant defects comprised two-thirds of the lips. The innervated serratus anterior muscle free flap was transferred to the lip and an end-to-end vascular anastomosis on the facial artery was performed. The marginal mandibular branch of the facial nerve was preferred for nerve coaptation. The inner and outer surfaces of the flaps were grafted with a split-thickness skin graft. Concentric needle electromyography of the orbicularis oris and frontal muscles was performed for all patients in the preoperative, postoperative, and follow-up periods. All patients survived the surgical operation. Three patients achieved perfect oral sphincter function without drooling. Electromyography at 1 year postoperative demonstrated the successful reinnervation of the serratus anterior muscle. This study demonstrates that lip reconstruction using an innervated serratus anterior muscle free flap is a reliable method, providing a functional lower lip.

Bupivacaine and ropivacaine: comparative effects on nerve conduction block.

Unlike other drugs which act in the region of the synapse, local anesthetics are agents that reversibly block the generation and conduction of nerve impulses along a nerve fiber. This study aims to investigate the comparative inhibitions of bupivacaine and ropivacaine on the frog sciatic nerve. Isolated nerves were transferred to the nerve chamber which includes Ringer's solution. The nerves were stimulated by standard square wave pulse protocols and the responses were recorded with conventional systems. Bupivacaine (n = 8) and ropivacaine (n = 8) were administered in the nerve chamber bath with cumulative concentrations (10(-9) to 10(-3) M) and the effects were monitored for variable time periods (5, 10 and 15 min). Both bupivacaine and ropivacaine significantly depressed the compound action potential (CAP) parameters in a dose-dependent (p < 0.05) and reversible manner. Difference in the effects of these two drugs was detectable only when the dose (> or =10(-5) M) and exposure time (15 min) were increased. Percent inhibitions in maximum derivatives and latency-period measurements have shown that ropivacaine is not only fast but also much more powerful in conduction block for longer and higher doses. Bupivacaine, on the other hand, is effective in the group of fibers with relatively slower conduction velocity for all the measured doses and time periods. In conclusion, ropivacaine has a sensory specific side of action, when compared with the bupivacaine.