ASSOCIATE PROFESSOR HAREWOOD
SPECIALISING IN ROBOTIC
OR "DA VINCI PROSTATECTOMY"
The immediate advantages to the patient are those of laparoscopic
and minimally invasive procedures, namely: reduced blood loss; reduced postoperative
discomfort; shorter hospital stay and quicker return to normal activities. 6
In Australia, open radical prostatectomy is typically associated with a blood loss of the order of 500 to 1500 cc, blood transfusion is common, hospital stay is of the order of 3 to 7 days and return to normal activities is commonly around 6 weeks. After Robotic Radical Prostatectomy blood loss is more typically of the order of 100 to 400 cc, blood transfusion is unusual, hospital stay is typically 2 to 3 days, and return to normal activities around 2 weeks.
Robotic Radical Prostatectomy also offers improved long term outcomes in terms of less erectile dysfunction and improved rates of continence.
Essential for the return of erectile function after radical prostatectomy is the preservation of the neurovascular bundle. This is a plexus of nerves formed by the sympathetic fibres of the hypogastric nerve joining with the pelvic splanchnic nerves. The pelvic splanchnic nerve is made up of parasympathetic fibres from S2, 3 and 4. This combined plexus sits vertically in the pelvis applied to the lateral aspect of the seminal vesicles and rectum. The plexus extends distally associated with branches of the inferior vesical vein and artery. This forms the neurovascular bundle. This passes on the postero-lateral aspect of the prostate in a triangular fascial compartment formed by the capsule of the prostate, the lateral prostatic fascia and the Denonvilliers fascia. The main nerve to the penis is the cavernous nerve which comprises a specific portion of this bundle, passing on the postero-lateral aspect of the prostate and urethra to reach the cavernous tissue. 7 Costello The bundle lies in very close proximity to the capsule of the prostate, lying a mean of 1.7mm away at the apex of the prostate, 2.7 mm away at the base of the prostate and 3.5 mm away at the tip of the seminal vesicles. 8 Ukimura and Gill.
To preserve the Neurovascular bundle with the cavernous nerves it is essential to accurately dissect the fascial planes around the prostate. The nerves are damaged if the dissection is taken too lateral. Traction on the nerves will produce a neuropraxia. Furthermore, it has been shown that diathermy used in proximity to the nerves causes heat damage. 9 Ong
The high resolution magnified view obtained with the robot facilitates the accurate, precise dissection of fascial layers essential in separating the neurovascular bundle from the capsule of the prostate. This dissection needs to be cautery free to minimize damage to the nerve plexus. This can be achieved by use of clips on the pedicle, or alternatively by the use of bulldog clamps to control the pedicle prior to suture ligation of bleeding vessels. When these procedures are used in men who are potent and under the age of 65, 74% were able to have successful sexual intercourse (with or without a pde5 drug) at 9 months post surgery. 10. 11. Ahlering
Better results again are reported when an extended nerve spare procedure is carried out. This entails a dissection that passes between the layers of the lateral prostatic fascia and the prostatic capsule. The dissection is carried from anterior to posterior to cleanly dissect on the prostatic capsule and hence pass deep to the neurovascular bundle. This results in a layer of fascia containing the nerves which has been termed the veil of Aphrodite. A study was carried out in potent men who had either a standard nerve spare procedure compared to a veil, extended nerve spare procedure. At 12 months follow up, 97% of patients having the veil procedure were able to have intercourse with or without a pde5 drug, compared to 74% of the control group. 12. Menon.
The risk to the patient in having a nerve spare procedure is that it increases the possibility of a positive margin. For this reason, the veil, extended nerve spare procedure is only feasible in patients with low risk disease. Ie: with a PSA of less than 10, a Gleason score of 6, and impalpable disease (stage T1c). If the patient has unilateral high grade T1c cancer or T2A (palpable) disease, then a standard nerve spare is feasible on the affected side, with a veil procedure on the clear lobe. Using these criteria, the incidence of positive margins is low, with only a 2% incidence in the veil group and a 3% incidence in the standard group in the above study. 12. Menon
Post operative continence depends on obtaining a good length of urethra, plus an accurate watertight anastomosis of the bladder neck to the urethra. This is facilitated by the six degrees of freedom of the robotic needle holders, together with the high resolution, 3 dimensional magnified image that is provided by the da Vinci robot. Continence appears to be regained early, with excellent long term control. Menon 13 reported 96% of patients at 6 months requiring either no pads or a security pad only. Patel reported 98% of patients at one year being continent, requiring no pads. 14. Patel.
In both situations, return of erections and achievement of continence is not always immediate, but is progressively obtained during the 12 months post surgery.
Despite these advantages, it is imperative that robotic radical prostatectomy provide equivalent or better oncological results to standard open surgery. This is indicated by the incidence of positive margins. This is defined as tumour being present at the stained margin in the histological specimen. Although having a positive margin, particularly if only focal, does not necessarily mean the patient is not cured, nevertheless, the incidence of PSA recurrence in patients with a positive margin is higher.
Ahlering reported an overall positive margin incidence of 10% in his robotic cases compared with 12% for his open surgery cases. Where the cancer was confined within the capsule of the prostate, (pT2A and pT2B) the positive margin rate was 4.5% in the robotic cases compared with 9.1% in his open surgery cases. 6. Ahlering.
Patel reported similar results with an overall positive margin rate of 10.5% with a positive margin rate for stage pT2 of only 5.7%.14. Patel These indicate that robotic radical prostatectomy is at least as effective as open surgery in achieving complete excision of the cancer.
Robotic radical prostatectomy appears to offer significant advantages over conventional open surgical radical prostatectomy.
Currently 30% to 40% of all radical prostatectomies in the United States are done robotically, and the number continues to rise. It is to be expected the same will occur in Australia as the technology becomes more widely available.