Presented by: Emily Serrell
University of Wisconsin

Introduction

Holmium laser enucleation of the prostate (HoLEP) aims to remove the entire prostate transition. Preoperative imaging estimates of whole gland volume (WGV) are often used to predict HoLEP enucleated volume. However, WGV and enucleated volume are sometimes discordant, implying variability in the ratio of TZV to WGV (transition zone index, TZI). We aim to evaluate the TZI and WGV relationship assess the concordance between HoLEP enucleated volume and MRI-estimated WGV and TZV.

Materials

A prospective HoLEP database was queried to identify patients with MRI within one year of HoLEP. TZI was calculated by dividing TZV by WGV. Patients were categorically stratified based on ellipsoid WGV, as measured by a radiologist. The ratio between TZI and WGV was assessed using stratified analysis and regression. Concordance was defined as the ratio of enucleated volume to WGV and TZV, with mean values compared using ANOVA.

Results

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We analyzed 218 patients with mean WGV of 101g (range 16.7 - 388) and TZV of 63.6g (range 6.06 - 346). Specimen weight was more concordant with TZV than WGV (mean 0.98 (SD 0.3) vs 0.56 (SD 0.19); p<0.001) Both TZV and WGV were positively correlated with specimen weight (r= 0.91 vs 0.88, p<0.001). Mean TZI and enucleated specimen concordance all varied significantly when stratified by prostate volume (Table). Regression analysis revealed a significant, positive, non-linear moderate relationship between WGV and TZI, but with high variability among individual patients (r=0.62) (Figure).

Conclusion

MRI-estimated TZV measurements are concordant with HoLEP enucleated volumes, especially when compared with WGV measurements. Larger prostates have a higher TZI, but TZI is highly variable between individuals and may not be accurately predicted by WGV alone. Therefore, preoperative transition zone measurement with MRI provides a valuable, accurate, and non-invasive tool for estimating enucleated volume prior to HoLEP.

Funding

None

Lead Authors

Matthew Grimes, MD
university of wisconsin

Co-Authors

Jordan Krieger, MD
University of SWisconsin

Margaret Knoedler,
University of WIsconsin

Shane Wells,
University of Wisconsin

Ali Antar,
University of Wisconsin

Ethan Richmond,
University of WIsconsin

Trevor Everett,
University of Wisconsin

Alex Thomas,
University of Wisconsin

Daniel Gralnek,
University of Wisconsin

Christopher Manakas,
University of wisconsin