Without a doubt, experienced prostate surgeons will identify numerous points of our technique that they perform differently. The point to emphasize for surgeons in training is that there are many ways to perform this operation that will be successful, so long as the principles of oncologic surgery are followed, while trying to minimize the side effects of incontinence and, when indicated, impotency. Again, we emphasize that careful ongoing review of one's personal pathologic and quality of life results is needed. Walsh has even recently described keeping video coverage of each case so that outcomes can be correlated with the original surgical technique.
However, several technical modificiations have been introduced that are aimed at making a significant impact on quality of life outcomes.
Cavernous nerve stimulation has recently been described. The Cavermap Surgical Aid (Uromed Corp., Boston, MA) is a system composed of a control unit, a probe handle with disposable tip containing eight stimulation electrodes in a 1.2 cm linear array,36 and a penile tumescence sensor. The device detects a 0.5% increase in penile girth as a positive response. Use of the device consists of establishing an initial response by a negative control (anterior bladder neck, for example) followed by a positive response at the posteriorlateral apex. The device is then used to map the course of the neuro-vascular bundle testing proximal and distal to proposed dissection planes (allow 45-60 seconds for detumescence). Following nerve-sparing prostatectomy, a positive response should be present at the bundle at the level of the bladder. Klotz etal.37 performed a randomized trial comparing Cavermap nervesparing versus conventional nerve-sparing surgery. In both groups, Cavermap was used at the end of dissection to document response. End-points were potency by questionnaire and Rigiscan at 1 year. Cavermap prolonged the operation by a mean of 17 minutes and increased blood loss by 25% (but not transfusion rates). A bilateral response was associated with recovery in 68%, while no response was associated with 0% recovery. At 6 months, erections in the Cavermap were seen in 60% compared to 45% in conventional nerve sparing (P = 0.10), and Rigiscan results were improved (P = 0.24).
While Cavermap in this trial showed improved results, Klotz36 has postulated that the Cavermap may improve the results in the control group, as the same surgeons were performing Cavermap versus non-Cavermap dissections by random assignment. Thus, Cavermap may not be an ongoing necessity for optimized outcomes, but may assist surgeons with less experience with the operation. Furthermore, nervesparing with Cavermap may lead to improved responses to Sildenafil, as well as assistance with sural nerve grafting.36 Other authors, however, have reported their experience with Cavermap to be suboptimal.38-40 Technology may provide more sensitive and specific monitoring in the future.
The decision to resect a neurovascular bundle is a significant challenge that requires individual counseling with the patient and careful review of one's results with positive margins. In terms of extracapsular, seminal vesicle and lymph node disease, all the urologist can do is obtain CT and bone scans (when clinically appropriate), and estimate the risks of these adverse findings with nomograms. Surgical margins, however, are under the control of the surgeon, and the posterior-lateral margin is a common area of spread of prostate cancer. Thus, non-nerve-sparing surgery is often indicated when prognostic factors such as Gleason score, PSA, palpable disease and high number/percentage of positive biopsy cores are present. The patient's age and potency status are also relevant factors. At the extremes the decisions are easy - the 68-year-old with erectile dysfunction should receive non-nerve-sparing, while the 52-year-old potent male with a small volume of Gleason 6 at the base or mid-prostate with a T1c lesion, PSA 4.5 should be offered at least a unilateral and probably a bilateral nervesparing approach.
Many patients, however, fall in the middle and have Gleason 4 + 3; 3 + 4 disease, apical disease, bilateral palpable disease, numerous bilateral positive cores, perineural involvement, and/or PSA >10. For the younger, fully potent patients, the decision is complicated by the simultaneous need for disease-free survival beyond 20-30 years and the desire to retain potency without the need for a vacuum erection pump, intracaverosal treatment or a prosthesis.
In an effort to offer the urologist more surgical options, Kim etal. have published preliminary data on resection of neurovascular bundles with interposition of sural nerve grafts. Their first report of nine patients treated with bilateral grafts showed improving spontaneous erections at 4-5 months.41 They have subsequently reported their technique on sural nerve harvesting,42 more details of the technique43 and their 1-year follow-up reporting unassisted intercourse in 4/12 patients, and an an additional 5/12 with a '40-60%' recovery of erections. The greatest return of function occurred at 14-18 months after surgery.44
These preliminary reports are promising, as patients with bilateral resection of neurovascular bundles rarely achieve spontaneous erections. Results with unilateral grafts will be more difficult to interpret, as erectile activity is preserved in some of these patients without grafting. Many authors, however, have reported that unilateral nerve-preservation results in a more than 50% reduction in erectile function, and thus there is potential for unilateral grafts to show a statistically significant benefit in a randomized trial.
The topic of sural nerve grafts has been debated in a recent publication.45 Both sides of the issue are well presented. While nerve grafts show efficacy, there is no expectation that they will ever be as effective as careful preservation of neuro-vascular bundles when cancer control can be accomplished. In theory, neurovascular bundle resection is only a benefit when there is extracapsular disease in that bundle that would have resulted in a positive margin, if nerve sparing was performed. In addition, it can be argued that a benefit is only present when the only site of a positive margin is at the neurovascular bundle. Thus, the surgeon is still left with the initial dilemma of when to resect a neurovascular bundle and, ultimately, the nature of one's patient population and referral patterns will determine the efficacy of nerve grafts. If a urologist establishes a practice known for bilateral nerve sparing, there will be a natural self-selection towards younger patients with low-risk disease, and nerve grafts are unlikely to show a benefit. On the other hand, if a urologist establishes a practice known for sural nerve grafting, there will be a natural self-selection towards higher risk disease where nerve grafting will show a benefit. In some European centers, PSA screening is not often recommended by primary care physicians, and the population of men undergoing radical prostatectomy have more advanced disease than those in the USA and nerve grafting may prove beneficial (Stefan Loening, personal communication). More data will be forthcoming from several centers including the Baylor College of Medicine, the Memorial Sloan-Kettering Cancer Center and the University of Texas MD Anderson Cancer Center. In addition, an experienced laparoscopic radical prostatectomy center has begun sural nerve grafting (Ingolf Türk, Charite Hospital, Berlin, personal communication).
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