Since the electrified TURP was invented 100 years ago by Dr. Maximilian Stern in 1926, the TURP has evolved greatly through the years in terms of optics as well as energy modalities used for resection.272 The original modern M-TURP with a loop dates back to the 1930s and uses hypotonic solutions such as water and glycine to allow for the electrical current to pass from the wire loop through the prostatic tissue which is in direct contact with the electrode. This procedure carries the risk of dilutional hyponatremia during a long procedure or one with large blood loss. Hence, the B-TURP evolved allowing for the use of more isotonic saline as an irrigant since both electrical poles are within the resectoscope. There are several different types of B-TURP resectoscope systems. For example, plasmakinetic resection of the prostate (PKRP) uses an active and return electrode separated by a ceramic insulator and thus electric current does not pass through the body.273 The transurethral resection in saline (TURis) system is another which uses an active electrode in the loop and a return collection electrode on the resectoscope sheath which can generate current flows and is often referred to as “quasi” bipolar.274-276 Four RCTs (N=946) compared B-TURP with M-TURP with follow-up from 6 months to 3 years. M-TURP and B-TURP were both effective in relieving LUTS and associated with similar improvements in quality of life scores at up to 3 years.274-277  In one of these RCTs by Al-Rawashdah et al. with 497 patients (comparing plasmakinetic [PK]-bipolar to monopolar), postoperative improvements in PVR, Qmax, IPSS, and quality of life scores were proved to be significant (p<0.0001) among both the M-TURP and B-TURP groups but there was no statistically significant difference between the two groups’ improvements.274 However, despite the equivocal efficacy in improvement of LUTS, the M-TURP group was associated with a statistically significant higher rate of transurethral resection (TUR) syndrome (2.78% versus 0%; p=0.001), longer length of stay (3.57 days versus 3.27 days; P=0.049), higher rates of blood transfusion (1.99% versus 0%; p=0.013), more blood loss (hemoglobin drop of 2.34 g/dL versus 1.6 g/dL; p<0.0001), and a higher urethral stricture rate (2.78% versus 0.40%; p=0.002).274  A second study by Komura et al. looked at 136 patients who were non-blinded to TURis B-TURP versus M-TURP at 1-, 3-, and 6-month follow-up.275 The TURis system for B-TURP provided similar results to those of conventional M-TURP past the study duration, with durable eﬃcacy findings even after 36-month follow-up. However, in regard to complications, patients in the M-TURP group were significantly more likely to have a decline in sodium levels than the TURis group p<0.01 but no patient in either group had clinical signs of TUR syndrome. In contrast to Al-Rawashdah et al.,274 there was no significant difference in blood loss and transfusion rates between the two groups. However, there was a higher clot retention rate (p=0.044) in the M-TURP group versus the B-TURP group which resulted in significantly shorter catheterization time and a shorter hospital stay in the B-TURP group.275 A prospective RCT of 100 patients comparing PK B-TURP versus M-TURP found no differences in IPSS, quality of life score, Qmax, and PVR at 1, 3, 6, and 12 months aside from a small quality of life score advantage to the PK B-TURP group at 12 months (MD: 0.9 points higher for PK B-TURP; 95% CI: 0.18 to 1.64; p=0.01) which was not perceivable by the patients and deemed a not clinically relevant outlier.277 Curiously, despite the longer operating room times for these PK B-TURPs, the longer surgical times did not correlate with higher amount of tissue resected nor did it correlate with more complications.277 In conclusion, M-TURP was as effective and safe as B-TURP.277 The B-TURP has been shown to have mean depth of thermal injury of 2.4 mm versus a mean coagulation depth of 1.52 mm.276, 278 The TURP remains the historical standard by which all other subsequent surgical approaches to treatment of BPH have often been compared and has long served as the reference group for other techniques. The Panel cannot recommend a specific prostate volume cut-off for TURP due to the heterogeneity of study reporting, however, the Panel’s expert opinion is that M-TURP is best utilized for patients with a prostate volume ≤80 cc.