title: Baseline erectile function alters the cavernous nerve quantity and distribution around the prostate.
abstract: OBJECTIVE
  We clarified the distribution of neuronal nitric oxide synthase positive nerve fibers around the prostate and factors contributing to fiber quantity.
  
  
  METHODS
  We investigated 46 hemispheres of 23 nonnerve sparing radical prostatectomy specimens from patients with available preoperative International Index of Erectile Function and maximum penile circumferential change data. We performed immunohistochemical staining with neuronal nitric oxide synthase antibody, and divided the prostatic hemisphere into 6 zones to assess the distribution of neuronal nitric oxide synthase positive nerve fibers at the apex, midportion and base of the prostate. Multivariate analysis of the quantity of overall neuronal nitric oxide synthase positive nerve fibers used the variables of specimen weight, patient age, body mass index, International Index of Erectile Function and maximum penile circumferential change. A maximum penile circumferential change of 20 mm or less was considered objective erectile dysfunction.
  
  
  RESULTS
  Median patient age was 68 years (range 57 to 74). Median International Index of Erectile Function-erectile function domain score was 12 (range 0 to 24) and median maximum penile circumferential change was 25.0 mm (range 2.70 to 38.3). Of the neuronal nitric oxide synthase positive nerve fibers 65% were distributed in a 3 to 5 o'clock sextant (p <0.001). Logistic regression analysis revealed that maximum penile circumferential change was the single significant variable (p = 0.019). The fiber count was greater in the objective erectile dysfunction group (median 1,500, range 382 to 2,760) than in the nonerectile dysfunction group (median 649, range 156 to 2,916) (p = 0.009). The fiber count was significantly different between the 2 groups in the 3 to 6 o'clock area, especially at the apex.
  
  
  CONCLUSIONS
  Baseline erectile function greatly impacts cavernous nerve quantity and distribution. Cavernous nerve preservation in the neurovascular bundle, especially at the apex, is still essential for patients with erectile dysfunction.
authors.affiliation: Department of Urology, School of Medicine, Sapporo Medical University, Sapporo, Hokkaido, Japan. hisasue@sapmed.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Hisasue
authors.forename: Kohei
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Ko
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Motoi
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Youki
authors.initials: Y
authors.lastname: Kyoda
authors.forename: Shiori
authors.initials: S
authors.lastname: Sato
authors.forename: Naoya
authors.initials: N
authors.lastname: Masumori
authors.forename: Taiji
authors.initials: T
authors.lastname: Tsukamoto
mesh_terms: D000368:Aged; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010410:Penile Erection / Q000502:physiology*; D011467:Prostate / Q000294:innervation*; D011468:Prostatectomy