Rajan Ramanathan

Real Time Monitoring of Temperature Changes in Neurovascular Bundles During Robotic Radical Prostatectomy: Thermal Map for Nerve-Sparing Radical Prostatectomy

OBJECTIVE A rise in temperature of more than 55 degrees C in tissues, even for short a duration has been implicated in irreversible tissue damage. This study was aimed at recording real time temperature changes at the neurovascular bundle (NVB) during the use of cautery in robotic radical prostatectomy. METHODS The temperature was monitored with a needle electrode in 15 cases of athermal nerve sparing and 10 cases of non-nerve sparing robotic radical prostatectomy (RRP). The needle was placed in the peritoneal cavity through the camera port and inserted around the NVB. Body temperature was recorded by nasal cannula and compared with the baseline temperature at the neurovascular bundle. The distance of the needle probe from the area of cautery use, changes in temperature at the neurovascular bundle and the duration of cautery use was recorded during the use of monopolar and bipolar current in tissue dissections. RESULTS The mean baseline temperature at the neurovascular bundle was 0.8 degrees C lower than the body temperature. Average duration for cautery use at the anterior bladder neck and NVB with monopolar and bipolar current was 53.6 (45-65) and 79.8 (70-92) and 56.8 (45-60) and 65.7 seconds (59-76) respectively. The mean temperature rise during bladder neck dissection (distance more than 1 cm) was 43.6 degrees C [36.4-47.3 degrees C] with the monopolar and 38.8 degrees C [36.8 degrees-42.6 degrees C] with bipolar. During NVB dissection, the mean temperature rise was 53.6 degrees C (45.1 to 68.1 degrees C) with monopolar and 60.91 degrees C (47.2 to 109.8 degrees C) with bipolar. Though this difference was not significant, the mean time to return to baseline temperature was 3 seconds more with bipolar than monopolar. CONCLUSIONS Bipolar cautery may not be safer than monopolar because of a greater rise in temperature of surrounding tissues within 1 cm of its use. Further investigation is needed to fully establish the pathologic consequences associated with increased temperature due to cautery.

Ablative therapies for renal tumors

Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation.

Optimization of Image-Guided Targeting in Renal Focal Therapy

Focal renal therapy for small renal masses (T(1a) or T(1b)) has been used as primary treatment for patients with comorbidities who are considered poor candidates for surgical resection. With a continuing effort toward optimization of minimally invasive nephron-sparing modalities, the effort to expand the patient pool will continue. As long-term results of renal ablative therapies become available and the safety, precision, and efficacy become well established, renal ablation may be used with increasing frequency for a wider group of patients. When this happens, high-quality imaging for localization and targeting of these renal lesions will become the central core of the treatment, with emphasis on superior results, accurate positioning of the probe, precise localization of the tumor, and real-time intraoperative monitoring of outcomes.

Second Prize: Pelvic Neuroanatomy and Innovative Approaches to Minimize Nerve Damage and Maximize Cancer Control in Patients Undergoing Robot-Assisted Radical Prostatectomy

Robot-assisted radical prostatectomy is an option for surgical management of clinically localized prostate cancer. There have been theoretical concerns, however, regarding lack of anatomic data with specific relevance to robot-assisted prostatectomy, use of thermal or electrical energy during nerve sparing, and lack of tactile feedback. To address these concerns, we have revisited anatomic foundations and have incorporated a few modifications and strategies in the technique of robot-assisted prostatectomy to maximize cancer control, preserve neurovascular tissue, and emulate time-tested steps of anatomic radical prostatectomy. We present our findings about neural anatomy, modified technique, and oncologic and functional outcomes from patients who have undergone this procedure at our institution.

Patient Positioning and Trocar Placement for Robotic Urologic Procedures

Robotic-assisted laparoscopic urologic surgery is fast becoming established as a standard of care for many urologic diseases. As more experience and long-term follow-up of procedures is accumulating, the safety of robotic technology is becoming well established. In this chapter we wish to describe logistical issues pertaining to patient positioning for the two areas of commonly performed urologic operations: those in the pelvis (prostate/ureter/bladder), and those for the upper tract (kidney/ureter/adrenal), in and around the kidney. General principles of patient positioning and port placement will be described followed by specific examples of complex situations, and how to overcome them.

Salvage Focal Therapy for Prostate Cancer

Radiation therapy (RT) is one of the treatment options for prostate cancer and around a third of patients opt to have RT; of these, approximately 30–40 % patients develop biochemical failure (BF). Patients who have BF often have a more aggressive form of prostate cancer. Organ confined BF is potentially curable using focal salvage therapy. Focal salvage therapy, however, has a higher complication rate and therefore suitable candidates should be carefully selected. A prostate biopsy should include sampling of the seminal vesicles. Appropriate evaluation for distant metastases should be done in select cases, depending on the PSA values, PSA doubling times and Gleason score. Recurrence of disease after salvage focal therapy is difficult to assess and further studies are needed to standardize criteria for biochemical failure after Focal salvage therapy.

1447 VALUE OF SERIAL PSA MEASUREMENTS FOR PROSTATE CANCER PREDICTION ON SCREENING USING A MAXIMUM LIKELIHOOD ESTIMATION - PROSTATE SPECIFIC ANTIGEN (MLE-PSA) MODEL

PSA measurements are used to assess the risk for prostate cancer. PSA range and PSA kinetics such as PSA velocity have been correlated with increased cancer detection and assist the clinician in deciding when prostate biopsy should be performed. Our aim is to evaluate the use of a novel, maximum likelihood estimation prostate specific antigen (MLE-PSA) model for predicting the probability of prostate cancer using serial PSA measurements combined with PSA velocity in order to assess whether this reduces the need for prostate biopsy. A total of 1976 Caucasian patients were included. All these patients had at least 6 PSA serial measurements; all underwent trans-rectal biopsy with minimum 12 cores within the past 10 years. A multivariate logistic regression model was developed using maximum likelihood estimation (MLE) based on the following parameters (age, at least 6 PSA serial measurements, baseline median natural logarithm of the PSA (ln(PSA)) and PSA velocity (ln(PSAV)), baseline process capability standard deviation of ln(PSA) and ln(PSAV), significant special causes of variation in ln(PSA) and ln(PSAV) detected using control chart logic, and the volatility of the ln(PSAV). We then compared prostate cancer probability using MLE-PSA to the results of prostate needle biopsy. The MLE-PSA model with a 50% cut-off probability has a sensitivity of 87%, specificity of 85%, positive predictive value (PPV) of 89%, and negative predictive value (NPV) of 82%. By contrast, a single PSA value with a 4ng/ml threshold has a sensitivity of 59%, specificity of 33%, PPV of 56%, and NPV of 36% using the same population of patients used to generate the MLE-PSA model. Based on serial PSA measurements, the use of the MLE-PSA model significantly (p-value < 0.0001) improves prostate cancer detection and reduces the need for prostate biopsy.

The Case for Robot-Assisted Radical Prostatectomy

MANAGEMENT of clinically localized prostate cancer is one of the most controversial subjects in the field of urologic oncology. Because of the lack of randomized trials, it is difficult, if not impossible, to compare two modalities used for treating an identical patient. Therefore, we will approach this debate more as an intellectual exercise, focusing on key outcome parameters. This exercise is not meant to give comparative data. Both laparoscopy and robotics are minimally invasive modalities. The goals of both are the same: To achieve oncologic control through negative margins and, in selected patients, to minimize damage to nervous tissue responsible for erections and urinary continence. Having said that, we enjoy performing robot-assisted prostatectomy and believe that the goals of prostatectomy are achievable using robotics in our hands. We present some technical, conceptual, and personal outcomes data to support our conclusions and provide objective data to clarify questions posed by the debate.