Abstract
Extraperitoneal (EP) robotic prostatectomy is not new. 1 In fact, it is old, and it has never enjoyed nearly the same popularity and level of adoption as the transperitoneal (TP) approach. 2 A good question would be “why?” and an even better question is “why are we revisiting this now?”
Single-port (SP) robotic prostatectomy has recently reinvigorated an otherwise mostly forgotten technique with few champions, but the EP approach is certainly not the only option for SP prostatectomy nor have we found any evidence EP is better with the SP robot than it was with the several generations of multiport robots for the past 20 years.
The arguments in favor of the EP approach are now being echoed by SP surgeons as if these arguments were new. They are not, nor are they any more applicable to SP surgery. The only difference is that the SP approach requires that an open incision be made rather than Veress needle access and does not require additional ports to be placed. EP access is certainly easier with SP surgery than it was with multiport surgery. But does that make it better or any more worthwhile than doing SP prostatectomies using a TP approach?
The arguments in favor of EP surgery, whether SP or multiport, include the argument that the abdominal cavity is never insufflated with the hopes of reduced ileus and perhaps less pain. It can avoid adhesions in patients with previous abdominal surgeries. 2 It can be performed without Trendelenburg positioning. 3 This all sounds great, so then why did the EP approach never take off for multiport surgery?
For one, the argument that EP surgery is better in patients with previous operations is not necessarily true. Accessing the EP space necessitates a preserved space of Retzius. But patients who have undergone midline abdominal incisions down to the pubis will often have obliteration of the normal plane used for finger or balloon dissection. Those who have undergone previous EP surgery such as for EP laparoscopic mesh inguinal hernia repair will have an even more challenging EP access. When EP access is possible in these patients with previous surgeries, the peritoneum can easily tear allowing gas to escape into the peritoneal cavity, negating the EP benefit of avoiding peritoneal insufflation.
Theoretically it sounds great if one can avoid intra-abdominal adhesions from previous surgery, but practically the likelihood of EP success in such cases is no better than the likelihood that the TP surgeon will be able to navigate the adhesions without much difficulty. In other words, the cases with severe adhesions (e.g., from multiple previous midline incisions) in which one would be frustrated with the TP approach are usually the ones most likely to make EP access difficult if not impossible. Otherwise, why would there ever be a need to develop perineal SP robotic prostatectomy (to avoid adhesions) when the same handful of surgeons who have done it do the rest of their SP prostatectomies EP! 4
Similarly, the theoretical advantage of avoiding Trendelenburg positioning might initially seem worthy of adopting the EP approach. Since the peritoneal cavity is avoided, there is no need for gravity retraction of bowels. Certainly, in the early days of robotic prostatectomy when some surgeons had 4- to 6-hour cases or even longer, the benefit of avoiding Trendelenburg could prevent the facial or airway edema sometimes seen. But with shorter operative times and judicious fluid management, this is a problem of the past, particularly when lower pneumoperitoneum pressures are used as discussed later. In addition, the fears that this positioning risks blindness, particularly in glaucoma patients, appears largely theoretical given that more than a million robotic prostatectomies have been performed (including glaucoma patients) with postoperative blindness being rare to the degree that it is relegated to case reports that always identify contributing factors such as unreasonably long operative times, use of vasopressors, and/or excessive intravenous fluids. 5 –7 Therefore, Trendelenburg positioning is not concerning enough to motivate an EP approach, and those surgeons who continue to have exceedingly long operative times where the position may cause concern are not likely the ones who will be able to learn and adopt EP surgery, especially not SP surgery.
Finally and perhaps most importantly, the most compelling argument in favor of the EP approach is the avoidance of pneumoperitoneum, which may reduce the risk of ileus, peritoneal stretch and potentially some resulting pain, and the possible physiologic effects of carbon dioxide absorption and impact on ventilation. All of these benefits combined may improve convalescence and reduce length of stay with many surgeons performing SP EP prostatectomy achieving same-day discharge in most patients.
Certainly, comparing the traditional pneumoperitoneum pressures used for laparoscopic and robotic surgery of 12 or 15 mm Hg with an intra-abdominal pressure of zero using EP surgery would be expected to yield obvious benefits. But the routine of using such high pneumoperitoneal pressures is no longer an unchallenged dogma. We have been performing TP robotic prostatectomy with a pneumoperitoneum pressure of 6 mm Hg since 2016 and have now performed >1600 consecutive cases without needing to raise the pressure. 8 With such a low pressure, ileus is virtually eliminated with most recently 98% of our patients able to go home the same day as surgery whether with the SP robot or multiport robot. 9 Therefore, the use of low pressures (and potentially even with pressures >6 mm Hg but still lower than traditional levels) can achieve all of the benefits of EP prostatectomy without the liabilities.
The liabilities of the EP approach and advantages of TP prostatectomy are several. TP access allows posterior dissection of the seminal vesicles as well as the option of a Retzius-sparing approach for those so inclined. The TP space is larger and less restrictive with the ability to perform more extensive lymph node dissection when needed without feeling confined. The approach is more familiar and is faster and easier to access by Veress needle insufflation.
Finally, the TP approach may reduce the risk of lymphoceles given that, at least in the early postoperative period, any lymphatic leak will be reabsorbed by the peritoneal cavity rather than accumulating and forming an endothelialized collection. Although symptomatic lymphoceles should be rare, two early series of SP prostatectomy performed EP reported lymphoceles requiring drainage in 6 of 60 patients and in 2 of 10 patients, whereas in our experience of >150 TP SP prostatectomies we have yet to experience one. 10,11 Lower volume surgeons or those learning the EP approach might experience lymphocele-related complications more frequently if not aware of the additional need to meticulously control lymphatic vessels without the “insurance” of peritoneal drainage, which is one of the treatments for managing lymphoceles (i.e., marsupialization into the peritoneum).
In summary, the EP approach to prostatectomy is not new. Its purported benefits are not enough to cause the TP approach, which has been enjoyed by surgeons for two decades, to now be reconsidered, whether because of the advent of the SP robot or otherwise. If the EP approach was so great, it would have been adopted by more than the vast minority of robotic prostatectomists already, and the SP robot is just as easily applied TP as it is EP, with the additional benefit of not having to learn a new robot as well as a new approach simultaneously. Particularly when using low pneumoperitoneum pressures in TP surgery, any benefits of EP surgery are imperceptible based on our experience and outcomes.