Experimental Research On Sensory Restoration In Reconstructed Penis

[ Background ] Phallic reconstruction is one of the most difficult operations in the field of plastic surgery. It is mainly used in congenital or acquired absence of the penis, or some of the sex deformity and transsexual disease. The procedure of phalloplasty, especially in the appearance of the penis and urethroplasty, has been improved successively and successfully since Bagoras initially prevented tubal flaps to reconstruct the penis in 1936. Nevertheless, the dysfunction of sensory of the reconstructed penis has puzzled the plastic surgeons all the times. The sensory restoration or recovery of reconstructed penis postoperatively can not only relieve the patient's agony of body and mind, but also ameliorate the surgical techqinue in phalloplasty. So far, no researches on the field have been reported yet at present.[Objective] The purpose of this study was to investigate the possibility of sensory restoration of the reconstructed penis that accomplished by denervated flaps and to establish an experimental phalloplasty with sensory restoration model in rabbits and to explore a new surgical technique to improve the postoperative sensory function in phallic reconstruction, so as to provide the experimental basis for its clinical application in the future. And then to investigate the changes and its significance of GDNF gene expression in dorsal root ganglion during the sensory restoration of phallic reconstruction in rabbits.[Methods](1)In part I : The experiment was performed with 8 adult male rabbits with the nerve tracing method of retrograde axonal transport of horseradish peroxidase (HRP), which was injected into the dermis around the penis and the dorsal nerve of penis. And then the rabbits were sacrificed five days later to havest the spinal cord segments and the dorsal root ganglia of lumbosacral segments for histological study.(2) In part: Sensory nerve implantation was applied in phalloplasty to establish the animal model of sensory restoration in phallic reconstruction, in which one lateral saphenous nerve graft was dissected as the donor nerve and end-to-end anastomosed to the one lateral dorsal nerve of pudendal nerve of the rabbit's penis, and subsequently embedded in a superficial epigastric faciovascular pedicle flap for phalloplasty. At different stage postoperatively, the process of growth of the reconstructed penile was observed grossly and histologically.(3) In part III: The forty adult male New Zealand white rabbits were randomly divided into experimental group (n=20) and control group (n=20), which were both performed phalloplasty with a superficial epigastric faciovascular pedicle flap. In the former group one saphenous nerve was dissected and end-to-end anastomosed to one lateral dorsal nerve of the rabbit's penis and then embedded in the flap, while the nerve implantation was not performed in the latter. The regenerated nerves were observed by CGRP immunohistochemical stain and HRP retrograde tracing method at different stage postoperatively. And other techniques including hematoxylin and eosin stain, immunohistology (En Vision method), Sevier-Munger Modified Silver Stain, cellular image analysis system, laser scan confocal microscope and electron microscope were also used to study the free sensory nerve endings, the regenerated axons and the Meissner's corpuscles of sensory nerves in the skin of the reconstructed penis. Meanwhile, the nerve fiber recording technique was used to observe the inductive velocity and discharges of nerve fibers wave at 3 month and 6 month postoperatively.(4) In part : Animal model of sensory restoration of phallic reconstruction in adult New Zealand male rabbits was established to detect the expression of GDNF mRNA in dorsal root ganglia at different stages postoperatively by reverse transcription polymerase chain reaction (RT-PCR).[Results](1) Part I : The HRP tracing showed that a numbe of labeled HRP positive neurons appeared in spinal ganglia (S2-S4) in all the 4 rabbits, and distribute segmentally.Quantitis of d...