In patients undergoing radical prostatectomy, the sural nerve is commonly used as a donor site for cavernous nerve grafting. Because of its accessibility, ease of dissection and lack of donor site morbidity, we believe the genitofemoral nerve is the ideal donor site for this procedure.
From 1999 to 2001, twelve patients with a minimum of one-year follow-up underwent radical prostatectomy with grafting from the genitofemoral nerve to the cavernous nerve. The genitofemoral nerve donor sites were evaluated post-operatively to assess morbidity. Evaluations consisted of retrospective chart review, patient questionnaires (including the McGill Pain Scale) and a detailed neurological examination within the sensory distribution of the genitofemoral nerve.
Only two patients noted residual numbness in the in the region supplied by the resected genitofemoral nerve. Neither patient felt the deficit interfered with normal daily activities. All patients denied the presence of any other adverse symptoms (burning, cold sensitivity or pain). On examination, only two patients (16.7%) were unable to discriminate between sharp vs. dull stimuli while seven patients (58.3%) experienced decreased light touch sensation in this region. Two patients (16.7%) had no measurable sensory deficits. In the remaining 10 patients, the average size of the deficit was 28.63 cm2. (range 12-63 cm2). Using Semmes-Weinstein monofilament testing, the average pressure sensitivity within this area was 4.77 g/mm2 (range 3.61 to 6.45 g/mm2) while the average pressure sensitivity within the control region was 2.92 g/mm2 (range 1.65 to 4.74 g/mm2).
Due to its low donor site morbidity, the genitofemoral nerve is an excellent donor source for cavernous nerve grafting during radical prostatectomy. In the majority of the patients, the sensory deficit produced by resection of this nerve is minimal and remains unnoticed. Harvest of this nerve prevents the additional morbidity associated with a donor site located elsewhere on the body (i.e. sural nerve).