| Penis reconstruction surgery is widely used in the treatment of penile defects, congenital malformations of gender, and female to male sexually transmitted diseases, which is of great significance. Currently, doctors have formed a standardized clinical consensus in remodeling penis shape, ensuring flap survival and urinary tract unobstructed, implanting supportive structures for stiffness, and even the reconstruction of penile sensitivity, etc. However, the progress on simulating the situation from weakness to firmness when penis erectile happens under the patients' subjective control has relatively lagged behind. In order to overcome the possible complications of artificial expansive implants, and to avoid the psychological shadow may happened in some patients for a erection initiating mechanism purely depending on an external force, we plan to use the innerved muscle transplantation to reconstruct the erectile function of penis.Gracilis has become a commonly used donor muscle for tissue defects and functional organ reconstruction, based on its anatomical characteristics and limited leg functional impact after its resection. In 1972, Orticochea reported a musculocutaneous gracilis transplanting surgery for penile reconstruction. Postoperatively, the reconstructive penis could move voluntarily when the initiative gracilis contraction happened. But the complicated surgical operation, rather long surgical duration, and the significantly overstaffed penis appearance had greatly affected the promotion of this surgical procedure. Recently, the progress on microsurgical techniques and flap prefabricating techniques makes it possible to simplify and shorten the surgical process. And the concept of muscle compartmentalization and its corresponding research achievements have brought hope to improve the overstaffed appearance of reconstructive penis at the same time. Yet, segmental flap application has also become a trend in musculocutaneous gracilis transplantation. In order to find the best balance between improving postoperative appearance and retaining muscle's contractive function, it is necessary to promote the anatomic and physiologic studies on gracilis. [Objective]Study the intramuscular nerve branches'and blood vessels'distribution of rabbit gracilis muscle and find a specific safe, simple way to split it completely. Build a suitable animal model for the reconstruction of penile erectile function with segmental gracilis flap transplantation, which can meet the requirements of both improving postoperative reconstructive penis's appearance and retaining muscle's contractive function.[Methods]1. Using a modified Sihler's intramuscular neural staining and red latex vascular perfusion technique to study the intramuscular nerve branches'and blood vessels' distribution of rabbit gracilis muscle.2. According to the principles of muscle compartmentalization, vertically split the rabbit gracilis muscle into two approximately equal halves completely. Observe the overall postoperative situation of muscle bundles'cross-section with HE staining technique. Observe the connective tissue's fibrosis occurred within the split muscle bundles with Masson's three-color staining technique. Detect the proliferation of muscle cells with En Vision immunohistochemical technology. Detect the apoptosis of muscle cells with TUNEL. Detect the dynamic level of muscle cell's proliferation with Western Blot. And using a multi-channel physiological signal acquisition and processing system to measure the isometric contraction forces and CMAP of muscle bundles synchronously.3. Build an animal model for the reconstruction of penile erectile function with segmental gracilis flap transplantation. Observe and record the morphologic changes and CMAP of the reconstructive penis when its nerve is electric stimulated.[Results]1. The intramuscular nerve primary branches of rabbit gracilis are generally parallel to each other and most of them are accompanied by a corresponding vessel branch. The blood vessels from different sources form an abundant microcirculation network through intramuscular vessel branches. The anterior 1/3-1/2 portion of the muscle is supplied by a branch of femoral artery and under the control of the anterior 3 primary nerve branches. While the posterior 1/2-2/3 portion of the muscle is supplied by a branch of profunda femoral artery and under the control of the anterior 2-3 primary nerve branches. 2. As the HE, Masson, En Vision IHC and TUNEL show:Early after the gracilis was split, the muscle bundles swelled obviously. The proliferation was active in both muscle cells and connective tissue cells. The activity of apoptosis was relatively higher in interstitial cells than it in muscle cells. The proportion of fibrous connective tissue increased greatly. The muscle bundles became compensatorily hypertrophy, which increased the muscle's wet weight obviously. With the passage of time, the muscle bundles'swelling relieved gradually. The proliferation activity dropped in both muscle cells and connective tissue cells, while the positive apoptosis cores were more often found in connective tissue cells. The proportion of fibrous connective tissue decreased and the muscle's wet weight reduced to near the preoperative level. The Western Blot showed an obvious trend that the PCNA expression level of muscle cells decreased gradually with postoperative time prolonged. It was found not only in the split muscle bundles, but also in the control side whole gracilis muscle. The Western Blot also implied that the surgical intervention of vertically splitting the rabbit gracilis muscle into two approximately equal halves would have little effect on the proliferation of muscle cells.3. After the rabbit gracilis muscle was vertically split into two approximately equal halves completely, the front muscle bundle was architected to build an animal model for the reconstruction of penile erectile function. When its dominant nerve was electric stimulated, especially when the muscle bundles occurred tetanic contraction, the 3 type of model were able to simulat the position changes, hardness changes and morphologic changes respectively, just like a normal erectile penis.[Conclusion]1. The intramuscular nerve branches'and blood vessels'distribution of rabbit gracilis muscle was displayed clearly and intuitively. Intramuscular nerve branches are generally parallel to each other and most of them are accompanied by a corresponding vessel branch. The anterior and posterior part of rabbit gracilis muscle seems to be regarded as two relatively independent sub-unit structures.2. The surgery according to the principles of muscle compartmentalization, which vertically split the rabbit gracilis muscle into two approximately equal halves completely, will not significantly affect the long-term survival of muscle bundles, nor shall it affect the contractive function of either muscle bundle respectively. 3. After the rabbit gracilis muscle was correctly split into two halves, the front muscle bundle was architected properly to build an animal model for reconstruction of penile erectile function, with a silicone stick implanted as a supporter. When its nerve was electric stimulated, the reconstructive penis could move satisfactorily, just simulating the way of a normal penis's erection.4. We also observed that the reconstructive penis model was able to paroxysm dithering under the animal's own control, which certified the feasibility of our surgical methods and supported the rabbit gracilis muscle compartmentalization.Our results have enriched the anatomic and physiologic study of gracilis compartmentalization. The reconstructive penis model has satisfactorily simulated the erectile function like that of a normal penis and has met the requirements of both improving postoperative reconstructive penis's appearance and retaining muscle's contractive function. It can be served as a useful reference for the further improvements of clinical penis reconstruction surgery. And it may also give some valuable advice on the application of segmental gracilis transplantation for the treatment of facial paralysis, the reconstruction of tongue function, and so on. |
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