The impact of vaporization on adenoma weight in benign prostatic hyperplasia surgery

The weight of adenoma removed during benign prostatic hyperplasia (BPH) surgery is commonly used as a surgical landmark. During endoscopic procedures, prostatic tissue is exposed to heat generated by electric current, resulting in tissue vaporization that may affect the final specimen weight. This study aimed to quantify tissue loss due to vaporization during TURP, comparing monopolar and bipolar techniques.

Surgical specimens from 32 patients undergoing open simple prostatectomy were analysed. After enucleation, adenomas were weighed and then completely resected in vitro simulating TURP using monopolar or bipolar energy. The weight of the resected fragments was measured to estimate tissue loss associated with each energy source and compared with preoperative MRI-estimated transition zone volumes.

Mean patient age was 68.2 ± 5.75 years. There was a strong correlation between MRI-estimated transition zone weight and enucleated specimen weight (97.5 ± 40.1 g vs. 90.5 ± 38 g; r = 0.998, p < 0.001). Of the 32 enucleated adenomas, 16 were resected in vitro using monopolar energy and 16 using bipolar energy. After in vitro resection of the adenoma, a significant decrease in the enucleated specimen weight was observed (from 90.5 ± 38 g to 64.25 ± 25.6 g; p < 0.001). Overall, the mean decrease in weight after resection was 26.3 g, corresponding to a 29% reduction. Bipolar resection showed a greater reduction in tissue weight compared to monopolar resection, with a decrease of 36.8% and 19.4%, respectively (p < 0.001).

The weight of the adenoma removed during surgical treatment of BPH differs depending on the technique used and, therefore, cannot be used comparatively between techniques. Resection surgeries result in tissue vaporization and dehydration, reducing adenoma weight by approximately 28%. Adenoma volume determination by MRI shows a strong correlation with the volume to be removed during surgery.