Tiam Mana Saffari

136 CHAPTER 7 Wounds were closed in layers, approximating muscle with two 5-0 absorbable interrupted sutures (5-0 Vicryl Rapide, Ethicon Inc., NJ, USA) and the skin was closed subcutaneously. After surgery, all animals were individually housed with ad libitum access to food and water. Survival period evaluation During the survival period, ultrasonography was used to measure cross-sectional scans of the tibial anterior muscle in the 16-week survival group and these were compared to the contralateral side, as previously described 27 . Non-survival evaluation At 12 and 16 weeks, the rats underwent a non-survival surgical procedure. Anesthesia was induced by an intraperitoneal injection of ketamine (Ketaset, 80 mg/kg; Fort Dodge Animal Health, Iowa, USA) and xylazine (10mg/kg) and maintained by ketamine (40mg/kg) throughout the procedure. Rats were kept warm at 37°C on the heating pad during this experiment. Ankle contracture angle - The ankle contracture angle was determined by measuring the angle between the anterior side of the tibia and the dorsal aspect of the paw with the ankle in maximal passive plantar flexion 5,28 . Electrophysiology (compound muscle action potential, CMAP) - The main sciatic nerve proximal to the graft was exposed and CMAP was measured using a miniature bipolar electrode connected to VikingQuest portable electromyelogram (Nicolet Biomedical, Madison, WI). A non-recurrent single stimulation was used with duration of 0.02milliseconds at an intensity level of 2.7mA. The maximal amplitude of the depolarization curve was recorded 5 . Maximum isometric tetanic force (ITF) - Maximum ITF measurements were performed as previously described 29 . Quantification of the ITF provides reproducible evaluation of functional recovery.