Masahiko Nakamoto

Zero Ischemia Anatomical Partial Nephrectomy: A Novel Approach

PURPOSE We present a novel concept of zero ischemia anatomical robotic and laparoscopic partial nephrectomy. MATERIALS AND METHODS Our technique primarily involves anatomical vascular microdissection and preemptive control of tumor specific, tertiary or higher order renal arterial branch(es) using neurosurgical aneurysm micro-bulldog clamps. In 58 consecutive patients the majority (70%) had anatomically complex tumors including central (67%), hilar (26%), completely intrarenal (23%), pT1b (18%) and solitary kidney (7%). Data were prospectively collected and analyzed from an institutional review board approved database. RESULTS Of 58 cases undergoing zero ischemia robotic (15) or laparoscopic (43) partial nephrectomy, 57 (98%) were completed without hilar clamping. Mean tumor size was 3.2 cm, mean ± SD R.E.N.A.L. score 7.0 ± 1.9, C-index 2.9 ± 2.4, operative time 4.4 hours, blood loss 206 cc and hospital stay 3.9 days. There were no intraoperative complications. Postoperative complications (22.8%) were low grade (Clavien grade 1 to 2) in 19.3% and high grade (Clavien grade 3 to 5) in 3.5%. All patients had negative cancer surgical margins (100%). Mean absolute and percent change in preoperative vs 4-month postoperative serum creatinine (0.2 mg/dl, 18%), estimated glomerular filtration rate (-11.4 ml/minute/1.73 m(2), 13%), and ipsilateral kidney function on radionuclide scanning at 6 months (-10%) correlated with mean percent kidney excised intraoperatively (18%). Although 21% of patients received a perioperative blood transfusion, no patient had acute or delayed renal hemorrhage, or lost a kidney. CONCLUSIONS The concept of zero ischemia robotic and laparoscopic partial nephrectomy is presented. This anatomical vascular microdissection of the artery first and then tumor allows even complex tumors to be excised without hilar clamping. Global surgical renal ischemia is unnecessary for the majority of patients undergoing robotic and laparoscopic partial nephrectomy at our institution.

Anatomic renal artery branch microdissection to facilitate zero-ischemia partial nephrectomy.

BACKGROUND Robot-assisted and laparoscopic partial nephrectomies (PNs) for medial tumors are technically challenging even with the hilum clamped and, until now, were impossible to perform with the hilum unclamped. OBJECTIVE Evaluate whether targeted vascular microdissection (VMD) of renal artery branches allows zero-ischemia PN to be performed even for challenging medial tumors. DESIGN, SETTING, AND PARTICIPANTS A prospective cohort evaluation of 44 patients with renal masses who underwent robot-assisted or laparoscopic zero-ischemia PN either with anatomic VMD (group 1; n=22) or without anatomic VMD (group 2; n=22) performed by a single surgeon from April 2010 to January 2011. INTERVENTION Zero-ischemia PN with VMD incorporates four maneuvers: (1) preoperative computed tomographic reconstruction of renal arterial branch anatomy, (2) anatomic dissection of targeted, tumor-specific tertiary or higher-order renal arterial branches, (3) neurosurgical aneurysm microsurgical bulldog clamp(s) for superselective tumor devascularization, and (4) transient, controlled reduction of blood pressure, if necessary. MEASUREMENTS Baseline, perioperative, and postoperative data were collected prospectively. RESULTS AND LIMITATIONS Group 1 tumors were larger (4.3 vs 2.6 cm; p=0.011), were more often hilar (41% vs 9%; p=0.09), were medial (59% and 23%; p=0.017), were closer to the hilum (1.46 vs 3.26 cm; p=0.0002), and had a lower C index score (2.1 vs 3.9; p=0.004) and higher RENAL nephrometry scores (7.7 vs 6.2; p=0.013). Despite greater complexity, no group 1 tumor required hilar clamping, and perioperative outcomes were similar to those of group 2: operating room time (4.7 and 4.1h), median blood loss (200 and 100ml), surgical margins for cancer (all negative), major complications (0% and 9%), and minor complications (18% and 14%). The median serum creatinine level was similar 2 mo postoperatively (1.2 and 1.3mg/dl). The study was limited by the relatively small sample size. CONCLUSIONS Anatomic targeted dissection and superselective control of tumor-specific renal arterial branches facilitate zero-ischemia PN. Even challenging medial and hilar tumors can be excised without hilar clamping. Global surgical renal ischemia has been eliminated for most patients undergoing PN at our institution.

Three-Dimensional Reconstruction of Renovascular-Tumor Anatomy to Facilitate Zero-Ischemia Partial Nephrectomy

Zero-ischemia robotic and laparoscopic partial nephrectomy, a novel concept, eliminates ischemia to the tumor-free normal kidney. Anatomic microdissection of tertiary/higher-order tumor-specific arteries is performed to selectively devascularize only the tumor, maintaining normal perfusion of the remaining kidney. A thorough understanding of renovascular tumor anatomy is essential. Based on 0.5-mm-slice thickness computed tomography scans, we developed a novel three-dimensional (3D) reconstruction technique that fuses three key anatomic aspects: surface-rendered tumor, semitransparent kidney, and extra- and intrarenal arterial anatomy. Four central completely intrarenal hilar masses underwent 3D reconstruction for surgical navigation during zero-ischemia partial nephrectomy. Negative surgical margins were obtained in all four cases, with no intraoperative complications or transfusions. For these challenging laparoscopically invisible masses, 3D image navigation precisely identified tumor-specific arterial branches, thus facilitating zero-ischemia partial nephrectomy without hilar cross clamping.

Prostate Swelling and Shift During High Intensity Focused Ultrasound: Implication for Targeted Focal Therapy

PURPOSE We quantified prostate swelling and the intraprostatic point shift during high intensity focused ultrasound using real-time ultrasound. MATERIALS AND METHODS The institutional review board approved this retrospective study. Whole gland high intensity focused ultrasound was done in 44 patients with clinically localized prostate cancer. Three high intensity focused ultrasound sessions were required to cover the entire prostate, including the anterior zone (session 1), middle zone (session 2) and posterior zone (session 3). Computer assisted 3-dimensional reconstructions based on 3 mm step-section images of intraoperative transrectal ultrasound were compared before and after each session. RESULTS Most prostate swelling and intraprostatic point shifts occurred during session 1. The median percent volume increase was 18% for the transition zone, 9% for the peripheral zone and 13% for the entire prostate. The volume percent increase in the transition zone (p <0.001), peripheral zone (p = 0.001) and entire prostate (p = 0.001) statistically depended on the volume of each area measured preoperatively. The median 3-dimensional intraprostatic shift was 3.7 mm (range 0.9 to 13) in the transition zone and 5.5 mm (range 0.2 to 14) in the peripheral zone. A significant negative linear correlation was found between the preoperative presumed circle area ratio, and the percent increase in prostate volume (p = 0.001) and shift (p = 0.01) during high intensity focused ultrasound. CONCLUSIONS We quantified significant prostate swelling and shift during high intensity focused ultrasound. Smaller prostates and a smaller preoperative presumed circle area ratio were associated with greater prostate swelling and intraprostatic shifts. Real-time intraoperative adjustment of the treatment plan impacts the achievement of precise targeting during high intensity focused ultrasound, especially in prostates with a smaller volume and/or a smaller preoperative presumed circle area ratio.

Three-dimensional navigation system integrating position-tracking technology with a movable tablet display for percutaneous targeting

To assess the feasibility of a novel percutaneous navigation system (Translucent Medical, Inc., Santa Cruz, CA, USA) that integrates position‐tracking technology with a movable tablet display.