Computer Modeling Technology to Assess Extracapsular Tissue Coverage of Whole Mount Sections After Retropubic and Laparoscopic Radical Prostatectomy

PurposeThe introduction of new surgical approaches to radical prostatectomy requires methodologies that permit valid comparison that are more expedient than long-term outcomes of biochemical local and distant failure and survival. We used a computer modeling program to assess the percent of extracapsular tissue coverage of prostate glands removed by the open retropubic and laparoscopic approaches.Materials and MethodsSpecimens were available for 15 and 17 patients who underwent open and laparoscopic radical prostatectomy, respectively. Serial whole mount sections were taken at 5 mm intervals. A genitourinary pathologist drew the contours of the prostate capsule on each tissue section. The whole mount was scanned to produce digital images. A software program was used to create a file with capsule information and a file with extraprostatic fibroadipose tissue information. Two separate point cloud files were generated to represent the capsule and extraprostatic models, and software algorithms were used to generate differences in the point clouds to quantify the extent of extracapsular tissue coverage.ResultsWhen separated into sides dissected by a nerve or nonnerve sparing technique, the overall percent of gland surface coverage by extracapsular fibroadipose tissue was statistically greater with laparoscopic dissection than with the open approach. When a segmental analysis of gland coverage was evaluated, a statistically greater percent of fibroadipose coverage was associated with laparoscopic dissection in the apical and inferolateral segments with nonnerve sparing, and in the apical segment with nerve sparing.ConclusionsThis small radical prostatectomy series, analyzed by computer reconstruction as described, provides information suggesting that overall extracapsular tissue coverage is at least equal if not superior using the laparoscopic vs the open approach. This was specifically the case in areas of inferolateral and apical dissection with nonnerve sparing procedures and in areas of the apical dissection with nerve sparing procedures.