UROLOGICAL SURVEY   ( Download pdf )

 

RECONSTRUCTIVE UROLOGY

Recovery of erectile function after unilateral and bilateral cavernous nerve interposition grafting during radical pelvic surgery
Satkunasivam R, Appu S, Al-Azab R, Hersey K, Lockwood G, Lipa J, Fleshner NE
Departments of Surgical Oncology (Division of Urology) (RS, SA, RAA, KH, NEF), Biostatistics (GL) and Plastic Surgery (JL), University Health Network, University of Toronto, Toronto, Ontario, Canada
J Urol. 2009; 17. [Epub ahead of print]

  • Purpose: The use of cavernous nerve interposition grafting to preserve erectile function in men who require neurovascular bundle resection for cancer control is controversial. We report outcomes and predictors of cavernous nerve interposition grafting in men undergoing unilateral grafting during radical prostatectomy or bilateral grafting during radical cystectomy and prostatectomy with autologous nerve grafts.
  • Materials and Methods: We retrospectively reviewed the electronic records of 36 patients who underwent cavernous nerve interposition grafting between 2003 and 2006. Postoperatively erectile function was assessed with the International Index of Erectile Function 15-item questionnaire. Predictors of potency, including age at surgery, time since surgery and prostate specific antigen at surgery, were assessed by univariate analysis.
  • Results: A total of 33 patients (92% response rate) were followed for a median of 32, 25 and 11 months after bilateral grafting during radical cystectomy (10), unilateral grafting during radical prostatectomy (20), and bilateral grafting during radical cystectomy and prostatectomy (3), respectively. The rate of potency, defined as the ability to attain and maintain erection sufficient for penetration at least 50% of the time with or without phosphodiesterase-5 inhibitors, was 31% (5 of 13 men) for unilateral grafts, 38% (5 of 16) for bilateral grafts and 30% (3 of 10) for bilateral grafts during radical cystectomy. Age at surgery was the only significant determinant of potency and it showed an inverse relationship in the bilateral nerve graft group (p = 0.02).
  • Conclusions: Cavernous nerve interposition grafting appears to have a role in the recovery of erectile function. To our knowledge this study represents the largest series of cavernous nerve interposition grafting during cystectomy and it suggests that this should be considered during bilateral neurovascular bundle resection.

  • Editorial Comment
    The reconstructive intraoperative approach of the cavernous nerve during radical prostatectomy or even cysto-prostatectomy represents a challenge for the surgeon. Satkunasivam et al. report in this paper their experience with unilateral and bilateral nerve grafting for the cavernous nerve reconstruction.
    Although it might still be a point of discussion which material is the best for the graft to re-establish erectile function; sural nerve, genitofemoral nerve or other sources (1,2). The authors used the genitofemoral nerve in 94% of the cases and in the remaining cases, the sural nerve. In a comparison of all cases with a bilateral graft, those patients that received the sural nerve graft were potent; whereas, using the author’s definition of potency, only 27.3% of the genitofemoral nerve graft patients were able to successfully maintain erection with a sufficient penetration rate of at least 50%.
    Satkunasivam et al. reported on the largest group of radical cystectomy patients who underwent intraoperative nerve grafting. Their findings are consistent with Anastasiadis’s report of a 30% success rate after bilateral nerve grafting subsequent to radical cystectomy (3). These reports underline that nerve grafting can be successfully achieved and should be performed if the morbidity of the patient is not endangered by the procedure. Perhaps with the further detailed knowledge about the peripheral nerves concourses on the prostate surface (4-6) and around the bladder, the successful outcome of nerve grafting can be further improved and nerve harvesting can be avoided with the use of regenerated acellular nerve grafts (7).

References
1. Secin FP, Koppie TM, Scardino PT, Eastham JA, Patel M, Bianco FJ, et al.: Bilateral cavernous nerve interposition grafting during radical retropubic prostatectomy: Memorial Sloan-Kettering Cancer Center experience. J Urol. 2007; 177: 664-8.
2. Nelson BA, Chang SS, Cookson MS, Smith JA Jr: Morbidity and efficacy of genitofemoral nerve grafts with radical retropubic prostatectomy. Urology. 2006; 67: 789-92.
3. Anastasiadis AG, Benson MC, Rosenwasser MP, Salomon L, El-Rashidy H, Ghafar MA, et al.: Cavernous nerve graft reconstruction during radical prostatectomy or radical cystectomy: safe and technically feasible. Prostate Cancer Prostatic Dis. 2003; 6: 56-60.
4. Sievert KD, Hennenlotter J, Laible IA, Amend B, Nagele U, Stenzl A: The Commonly Performed Nerve Sparing Total Prostatectomy Does Not Acknowledge the Actual Nerve Courses. J Urol. 2009; 14. [Epub ahead of print]
5. Sievert KD, Hennenlotter J, Laible I, Amend B, Schilling D, Anastasiadis A, et al.: The periprostatic autonomic nerves--bundle or layer? Eur Urol. 2008; 54: 1109-16.
6. Ganzer R, Blana A, Gaumann A, Stolzenburg JU, Rabenalt R, Bach T, et al.: Topographical anatomy of periprostatic and capsular nerves: quantification and computerised planimetry. Eur Urol. 2008; 54: 353-61.
7. Connolly SS, Yoo JJ, Abouheba M, Soker S, McDougal WS, Atala A: Cavernous nerve regeneration using acellular nerve grafts. World J Urol. 2008; 26: 333-9.

Dr. Karl-Dietrich Sievert &
Dr. Arnulf Stenzl
Department of Urology
Eberhard-Karls-University Tuebingen
Tuebingen, Germany
E-mail: arnulf.stenzl@med.uni-tuebingen.de