Prefabrication of periosteal graft alone or with oxidised cellulose: an experimental study.

The purpose of this study was to evaluate the feasibility of prefabrication of periosteal grafts, alone or with oxidised cellulose (surgicel), which was an osteoinductive material using femoral vasculature. Fifteen white New Zealand rabbits were used in both femoral regions (30 grafts), and randomly divided into three groups including five rabbits (10 grafts): the control group, the periosteal graft group, and the periosteal graft+surgicel group. A periosteal graft, 30 x 40 mm in size, was obtained from the calvarium of each rabbit. The periosteal graft taken was divided into two equal parts, 20 x 30 mm. All these periosteal grafts were sutured in the shape of tube. In all rabbits, femoral vasculature and periosteal tube was Included in a silicone tube. Additionally, in the control group, femoral vasculature was cut above and below the silicone tube, whereas in the periosteal graft+surgicel group, surgicel was added to the periosteal graft. The results were evaluated macroscopically and histopathologically in the second (two rabbits for each group - 4 grafts) and fourth week (3 rabbits for each group - 6 grafts). In the second week, In all three groups, while no osteoid tissue that indicated osteogenesis developed, it was seen that inflammation and increased vascularity occurred. Surgicel was observed to be absorbed in the periosteal graft+surgicel group. In the fourth week, fibrotic tissue was developed whereas inflammatory tissue disappeared; any osteoid tissue or lamellar bone was not accompanied in all three groups. In conclusion, we do not believe that periosteum was able to survive as a graft, and we found that neovascularization occurred too slowly to preserve the bone forming qualities of the periosteum. We suggested that it could not be prefabricated, being taken away from its donor site although surgicel was used as a stimulating material.

The fate of neurotization techniques on reinnervation after denervation of the gastrocnemius muscle: an experimental study.

In nerve injuries, if it is not possible to reinnervate muscle by using neurorrhaphy and nerve grafting technique, reinnervation should be provided by the use of neuroization-directly implanting motor nerve into muscle. A comparative study of three techniques of neurotization is presented in rabbits. In this experimental study, a total of 40 white New Zealand rabbits were used and divided into four groups, each including 10 rabbits. In the first group (control--Group 1), only surgical exposure of the gastrocnemius muscle, main muscle nerve (tibial nerve), and peroneal nerve was done, without any injury to the nerves. In the second group (direct neurotization group--Group 2), the tibial nerve was transected, and the peroneal nerve, which had already been divided into fascicles, was implanted into the lateral head of the gastrocnemius muscle aneural zone. In the third group (dual neurotization group--Group 3), the tibial nerve which had been transected and re-anastomosed, and the peroneal nerve were implanted into the lateral head of the gastrocnemius muscle. In the last experimental group (hyperneurotization group--Group 4), fascicles of the peroneal nerve were implanted into the lateral head of the gastrocnemius, preserving the tibial nerve. Six months later, changes in the histologic pattern and the functional recovery of the gastrocnemius muscle were investigated. It was found that functional recovery was achieved in all neurotization groups. Groups with the tibial nerve transected had less muscular weights than those of groups with the tibial nerve intact. EMG recordings showed that polyphasic and late potentials were frequently seen in groups with the tibial nerve transected. Degeneration and regeneration of myofibrils was observed in such groups as well. New motor end-plates, including vesicles, were formed in a scattered manner in all neurotization groups. As a result, the authors conclude that direct and dual neurotization techniques are useful in peripheral nerve injuries, if it is not possible to reinnervate muscle by using neurorraphy and nerve grafting, and that there is no suggested superiority among these techniques.

Effects of some pharmacological agents on the survival of unipedicled venous flaps: an experimental study.

Clinical and experimental studies have been conducted to improve the survival of venous flaps. As a result of these studies, although various survival mechanisms were raised, none obtained satisfactory information. Venous stasis, and the resultant venous thrombosis, is a factor that decreases the survival of venous flaps. In this study, we evaluated the effects of two antiinflammatory agents, etodolac and etofenamate, on the survival of unipedicled venous flaps. In this study, 35 male New Zealand white rabbits (3,500-4,000 g) (70 ears) were used. Perichondrocutaneous flaps, 3 x 4.5 cm in size, were designed and raised, keeping the central veins intact in the middle of venous flap. Central arteries and nerves were ligated and transected both proximally and distally, to prepare unipedicled venous flaps. A silicone sheet was placed between the cartilage tissue and flap, to prevent blood flow and revascularization beneath. The subjects were divided into seven groups, consisting of five rabbits (10 ears). In the negative control group (group I), the single vascular pedicle of venous flaps, central veins were ligated and flaps sutured into their own place as the composite graft. In the positive control group (group II), after venous flaps were prepared, normal saline, 0.2 mL, was given subcutaneously. In the first of five experimental groups (group III), unfractionated heparin (100 U/day) was given subcutaneously. In the second experimental group (group IV), etodolac (5 mg/kg/day) was given subcutaneously. In the third experimental group (group V), etophenamate (5 mg/kg/day) was given orally through a feeding tube. In the fourth experimental group (group VI), parnaparin (5 anti-Xa U/kg/day) was given subcutaneously. In the fifth experimental group (group VII), nadroparin (5 anti-Xa U/kg/day) was given subcutaneously, about 7 days postoperatively. At the eighth postoperative day, surviving areas of venous flaps were measured, and the results were evaluated by Kruskal-Wallis ANOVA and Mann-Whitney U-test (P < 0.05). Biopsies were also taken from the flaps for histological evaluation of border of necrotic tissue. Surviving areas of unipedicled venous flaps were larger in experimental groups than those in negative and positive control group (P < 0.05). However, comparison of the experimental groups demonstrated no statistically significant difference (P > 0.05). We concluded that all pharmacological agents used in the experimental groups succeeded in increasing the survival of unipedicled venous flaps. Survival of the unipedicled venous flap was higher in venous flaps than that of composite graft, clearly showing the importance of the venous pedicle.