New “nerve sparing score” predicts post-surgical erectile function


The prostate cancer research team at Memorial Sloan-Kettering Cancer Center (MSKCC) has proposed and tested a new means for categorizing the amount of “damage” to the cavernous nerves as a method of predicting preservation of erectile  function after radical prostatectomy.

The proposed MSKCC nerve sparing score (NSS) is assigned by the patient’s surgeon at the time of surgery. For each neurovascular bundle (one on each side of the prostate), the surgeon is asked to assign a number from 1 (complete preservation of the nerves) to 4 (complete reseaction of the nerves). This means that a patient can have a post-surgical NSS of anything from 2 (complete preservation of both nerves) to 8 (complete resection of both nerves).

Moskovics et al. have now published data on the ability of the NSS to predict preservation of erectile function at up to 2 years after surgery.

The research team collected preoperative baseline data from patients who were scheduled for radical prostatectomy. The baseline data included International Index of Erectile Function (IIEF)-erectile function domain (EFD) scores. At the time of RP, all patients were assigned an NSS as described above. Patients with preoperative EFD scores ≥ 24 (out of a highest possible score of 30) were then asked to complete IIEF questionnaires again at 24 months after their surgery.

The results of the analysis were as follows:

  • 173 patients were eligible for this analysis.
  • The average (mean) age of the patients was relatively young, at 59 years.
  • 62 percent of the patients had at least one comorbid condition.
  • Baseline EFD scores were comparable between all NSS assignments.
  • At 24 months post-surgery, EFD scores were all reduced, on average.
    • For patients with an NNS of 2, EFD was reduced by 7.2.
    • For patients with an NSS of 3, EFD was reduced by 11.6.
    • For patients with an NSS of 4, EFD was reduced by 13.9.
    • For patients with an NSS of 5 to 8, EFD was reduced by 15.4.
  • Multivariate analysis showed that baseline EFD score, age, and NSS all had significant value in predicting recovery of erectile function at 24 months post-surgery.

The authors conclude that the NSS can help to more precisely predict erectile function outcomes at 2 years after surgery. However, they also conclude that “even minor nerve trauma significantly impairs the recovery of erectile function after procedures classically regarded as having achieved bilateral nerve sparing.”

It has long been understood that “nerve-sparing” surgery is no guarantee of high quality erectile function post-surgery. This study documents an average 30 percent reduction in erectile function even for patients who have both nerves fully preserved at radical prostatectomy at one of the most respected prostate cancer surgery centers in the world. The “New” Prostate Cancer InfoLink considers this to be an important new piece of information for patients, because it gives us better guidance as the expectations after radical prostatectomy. This is a particularly important piece of information for newly diagnosed patients, who may otherwise be led to have unduly optimistic expectations about post-surgical recovery of erectile function.

This is not the first time a nerve sparing scoring system has been proposed. In early 2008, Levinson et al. proposed a comparable system and showed comparable results. We should also note that, since we have only seen the abstract of the current paper by Moskovics et al., we do not know exactly what characterizes an NSS of 2 or 3 (by comparison of 1 and 4) in assigning the NSS for each set of nerves at the time of surgery. Finally, there is no information in the abstract about whether assessment of the post-surgical recovery of erectile function allowed for the use of phosphodiesterase inhibitors like sildenafil (Viagra). We have to suspect that it did. In other words, “chemical help” may have been required to achieve the levels of erectile function reported post-surgery.

One Response

  1. Perhaps the prostate cancer industry should be forced to take a page from state legislatures and anti-choice groups. A written statement should be prepared that describes in detail the risks and probable outcomes of RRP. Every patient everywhere should have full knowledge of what’s going to happen to them — including the very real probability that they’re are one of the 47 who doesn’t need the RRP instead of the 48th who does.

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