What are the steps involved during our “tailored” robotic prostatectomy?
Posterior dissection of seminal vesicles and prostate
- The seminal vesicles are cystic structures attached to the prostate and function in storing and adding the nutrients to the semen. The seminal vesicles are always removed with the prostate during surgery. A posterior approach allows for energy free and traction free dissection of the nerve bundles that run along the side and tips of the seminal vesicles. The posterior approach also allows for perfect visualization of large or asymmetric seminal vesicles, situations which could be very complicated in an anterior approach. In addition, this type of approach allows us to bypass a large median lobe (protrusion of the prostate into the bladder) without compromising visualization.
Developing the space of Retzius and anterior prostate dissection with sparing of the Endopelvic Fascia
- This step drops the bladder and the prostate from the abdominal wall. It allows the surgeon direct visualization of the anterior prostate and the dorsal vascular complex. By sparing the Endopelvic fascia, an Intra-facial dissection is more likely to be successful. See neurovascual bundle dissection below for more details.
Division of the prostate from the bladder by bladder-neck sparing technique to preserve the internal sphincter mechanism
- The bladder and prostate are fused together by two layers of bladder muscle in addition to fatty tissue. This area includes the internal urinary sphincter that includes muscle fibers that have a role in the subconscious control of urinary function. In most patients preservation of the bladder neck sphincter mechanism can result in early urinary continence. A proper preservation can also decrease the risk of strictures or scars of the bladder neck known as bladder neck contractures. When the bladder neck is not spared, the subsequent large opening may result in a time-consuming reconstruction to taper the opening. Larger openings also require a longer suture line and therefore may be more susceptible to leakage of urine from the anastamsosis. Given all these factors and assuming there are no biopsy features putting the patient at risk for bladder neck involvement or the presence of a large median lobe, we always strive to preserve the bladder neck.
Dissection of lateral prostatic fascia and sparing of the neurovascular bundles (NVB)
The nerve bundles carry neural information and blood flow into the deep pelvis. These structures are critical for both erections and urinary control after surgery. Multiple studies to date have shown a direct relationship between the degree of nerve sparing and post-operative potency and urinary control. Contrary to what most patients believe, the nerve sparing is not an all or none concept. Depending on the extent of the cancer, the nerve dissection can be individually tailored to the patient and his cancer. Many factors come into the decision but include the risk of extracapsular extension based on pre-operative nomograms/risk-tables (link to separate section/post), the results of pre-operative T3 MRI of the prostate (link so section), the findings of a rectal exam under anesthesia, intra-operative findings and the ease of “peeling” the bundles away from the prostate. The degree of precision and dexterity that is needed to perform the dissection of the nerve bundles away from the prostate is similar to what is required to “peel” the skin off of a table top grape (link to video). Our goal is to clearly remove all prostate and cancerous tissue but as important of a goal is to leave all non-prostate tissue as it was prior to the surgery. Many times, surgeons use the terms extrafascial, interfascial, and intrafascial to describe different techniques to dissect the prostate and the nerve bundles.
- Extrafascial: This is also known as non-nerve sparing or wide-excision dissection. When there is either high suspicion that the tumor has penetrated the capsule wall deep into the extracapsular fatty tissue or is involving the nerve bundle itself this may require us to resect the nerve bundle all together with the prostate. Usually a pre-operative MRI can identify the extent of involvement. In this type of dissection, the endopelvic fascia is incised deep near the levator ani muscles to carry out this type of dissection. In patients who are not interested in nerve preservation due to baseline erectile dysfunction a wide-excision may not be critical. However, even in patients with clear evidence of extracapsular involvement we may be able to do a graded dissection and spare some of the neurovascular bundle on the side affected with cancer in hopes of maximizing post-surgical potency. We use intra-operative frozen sections whereby we send tissue at the edge of the dissection to get a preliminary assessment of any tumor at the margin and subsequently guide our dissection based on those results. We are also currently working on a novel technology that will be able to guide us in real-time identification of prostate tumor using fluorescent dyes targeting the tumor and near-infared imaging similar to what we have been able to pioneer with kidney cancer surgery (link to Firefly). Although we are currently evaluating with this technology in an animal model, we hope to soon apply this to clinical use and recruit patients into a clinical trial.
- Interfascial dissection: The endopelvic fascia is incised and the neurovascular bundles are spared posterolaterally to take some of the tissue around the prostate (periprostatic fascia) with the specimen. The component of nerves and vessels that can sometimes be found on the anterior aspect of the prostate are therefore not spared. As noted above, the clinical extent of the tumor has an impact of whether or not we decide to do this type of graded dissection.
- Intrafascial dissection: This is the most delicate and precise type of dissection. Think of this as a custom-made, very “fitted” type of dissection. In this type of dissection, the endoplevic fascia, the neurovascular bundles, the periprostatic fascia and Denonvillier’s fascia are all spared and left intact. The plane of dissection is directly guided on top of the prostate capsule. By sparing all these structures, we maximize the patient’s chance of regaining erection and urinary control after surgery.
Control of dorsal vascular complex (DVC)
- As its name implies, the DVC contains an array of both veins and arteries that carry and drain blood from the penis. Due to the large amount of blood flowing in this structure, inadvertent injury can result in significant amount of bleeding. The higher amount of blood loss associated historically with open prostatectomy techniques was related directly to this point of the procedure. Fortunately, with the utilization of the CO2 gas utilized for laparoscopic and robotic surgery, venous bleeding from the DVC is no longer a major issue as the gas can provide passive pressure and prevent oozing from this area. Two methods are used to control the DVC: either suture ligation or endoscopic stapling. One of our preferred methods of control is to used an endoscopic stapler. As we have previously published, endoscopic stapling allows for a consistent, efficient and reliable method for getting control without risking a positive margin at the apex of the prostate.
Preparation of Apical Urethra – preserve length and muscle fibers
- Prostates come in all sizes and shapes. Some are smaller, some are bigger. Most of the variation that can be seen in shape is usually seen at the apex. The apical prostate surrounds the urethra near the external sphincter complex. The goal at this point of the operation is to achieve a long and thick urethral stump that will subsequently be re-connected to the bladder neck. There is a fine line between dissecting too deep (the levator muscles and the external sphincter complex can be inadvertently damaged) or too shallow (risk leaving prostate tissue behind).
- Also known as a Male sling, Rocco reconstruction or Rhabdosphincter reapproximation. This technique allows for a posterior support of the sphincter complex like a hammock and prevents the urethra from slipping further down into the pelvis during activity which may lead to leakage such as coughing, sneezing or laughing. The reconstruction also brings the bladder down into a supported position and therefore removes any tension on the completed urethra-bladder anastamosis. Most experts agree that this type of reconstruction leads to shorter recovery times to recover urinary control.
- The goal at this point of the procedure is to create a watertight and tension-free connection between the urethra and the prostate. One of the most important advancements to our practice has been the ability to utilize a barbed suture (V-Loc Link to Covidien) that maintains the reapproximated ends without allowing any gaps between the edges of the tissue. As a results for years now we have avoided using any post-oeprative drains unless we are dealing with a very large bladder neck or a reconstructed bladder neck.
- Even tough pre-operative CT or MRI may not show evidence of regional lymph node involvement, the accuracy of these imaging tests is only around 80%. The decision to identify and remove the lymph nodes that drain the prostate during prostatectomy is made on an individual basis. We calculate risk of lymph node involvement based on widely available nomograms and risk calculators such as D’Amico criteria, Partin Tables, CAPRA score, or MSKCC calculator. Low risk patients (for example those with PSA < 10, Gleason 6, or clinical T1c) clearly do not benefit from a lymph node dissection. Intermediate risk patients and High risk patients on the other hand may benefit from a lymphadenectomy. It is believed that an extended lymph node dissection (in both lymph node negative and positive patients) may lead to the removal of undetected micrometastases, and therefore improve the survival of patients undergoing prostatectomy. There is a growing body of evidence suggesting that the greater the number of lymph nodes removed is beneficial. However, no uniform consensus exists regarding the limits of boundary of the dissection or the minimum number of lymph nodes that should be removed. Historically, the detection of suspicious lymph nodes at the time of radical prostatectomy lead many surgeons to abandon the operation with the belief that regional lymph node involvement was a sign of widespread metastatic disease and therefore associated with poor prognosis. Patients would subsequently be referred for treatment with hormones and/or radiotherapy. However, there have been a number of recent studies showing very reasonable cancer-specific survival rates even in patients with lymph node positive disease at the time of radical prostatectomy. A recent publication from the European Journal of Urology analyzed the Munich cancer registry and found that patients with lymph node positive disease that did not have their operation aborted on average had 20% improvement in survival compared to those who had their operation aborted.