Anatomy of the neurovascular bundle: Is safe mobilization possible?

Purpose: We have previously defined the anatomy of the neurovascular bundle in the normal and hypospadiac penis. Historical experience suggests that m obilization of the neurovascular bundle is anatomically possible. We attemp t to prove whether mobilization of the neurovascular bundle is safe and the oretically sound. Specific questions that will be addressed are does the ne urovascular bundle send perforating branches into the corporal bodies; how far lateral does the dissection need to be before nerves are injured and ex actly how deep into Buck's fascia must one go. Materials and Methods: A total of 35 normal human fetal penile specimens, g estational age 8 to 35 weeks, and 3 hypospadiac specimens, 33 to 41 weeks o f gestation, were serially sectioned and stained with Mason's trichrome and the neuronal markers PGP 9.5 or S100. Computer reconstruction using commer cial software and National Institutes of Health imaging allowed 3-dimension al analysis of the nerves, corporal bodies and glans. Results: Perforating nerves into the erectile bodies were not documented al ong the dorsal or lateral aspect of the tunica in any of the specimens stud ied. Only in the area of the crural bodies on the ventral lateral surface w ere nerves noted to pierce into erectile tissue. The neural network was ext ensive from the 11 and 1 to the 5 and 7 o'clock positions corresponding to the erectile tissue and urethral spongiosum junction. At this junction mino r nerve branches were noted to perforate into the urethral spongiosum. A mi croscopic plane exists between the neurovascular bundle and tunica of the c orporal bodies measuring 20 to 30 mu. in specimens greater than 30 weeks in gestation. Conclusions: Perforating branches from the dorsal lateral neurovascular bun dle do not exist based on serial step sectioning and microscopic examinatio n of male genital specimens. Surgically it is possible to elevate the neuro vascular bundle but the dissection needs to remain directly on top of the t unica albuginea to prevent neuronal injury. Small perforating branches into the urethral spongiosum may be injured with unknown significance. We conti nue to advocate plication in the nerve-free zone at the 12 o'clock position for correction of penile curvature.