Efficacy and Long-term Durability of Middle Lobe Only (MLO) Versus Complete Trans-Urethral Vaporization of the Prostate (PVP), Prospective Cohort Study.

Introduction:

Transurethral resection of the prostate (TURP) is considered the treatment of choice for patients suffering from benign prostatic hyperplasia (BPH) refractory to medical treatments or in patients with refractory urinary retention (1). It involves complete resection of the transitional zone of the prostate from the verumontanum to the bladder neck (2). Classical TURP has a high risk of ejaculatory dysfunction (65-70%) (2), and a 7% to 13% risk of bleeding that requires transfusion (3). To reduce these complications, newer technologies have been introduced to lower these associated risks, such as greenlight laser, Rezum, and Urolift (1).

The dynamic of bladder outlet obstruction related to BPH adenoma site and distribution has not been completely elucidated. In a study that looked into this relationship, it suggested that the presence of intravesical prostatic protrusion (IPP) has been associated with the presence of prostatic adenoma with high sensitivity (95.4%), a high specificity (100%), and a high positive predictive value (100%), with the negative predictive value of (50%). Furthermore, the mean maximum flow rate (Qmax) in patients with only lateral lobe prostatic adenoma evaluated by cystoscopy was 16ml/s, while patients with middle lobe only adenoma have a flow max of 11.6 ml/s. When patients have both middle and lateral lobes, the mean Qmax was 8.9 ml/sec (4). These findings highlight the major role of middle lobe adenoma and intravesical prostatic protrusion (which is usually an extension of the middle lobe), into the urodynamics of bladder outlet obstruction. Also, the intravesical prostatic extension has been suggested to cause a "ball-valve" effect that contributes significantly to the urodynamic bladder outlet obstruction (5). In a retrospective study, middle lobe only TURP for patients with prominent middle lobe adenoma and IPP of more than 10 mm, in patients with bothersome BPH symptoms or urinary retention, was associated with improvement in Qmax, Post-void residual and reduction of the international prostate symptoms score (IPSS), over a follow-up period up to 12 years. The urodynamic outcomes were comparable to traditional TURP results but with no change in ejaculatory bother scores pre and postoperatively. It also enabled including patients with larger prostate sizes (up to 178 g) that would require open prostatectomy or complete laser enucleation of the prostate (5).

Rationale:

Middle-lobe only TURP procedure has demonstrated durable, successful urodynamic outcomes in patients with significant bladder outlet obstruction caused by middle lobe with IPP of more than 10 mm, with no change in ejaculatory status after such procedure in retrospective fashion (5). No prospective studies have been done to document this effect. Also, the use of this procedure in patients with predominant meddle-lobe prostatic adenoma with minimal or no IPP has not been evaluated. Furthermore, the use of greenlight vaporization, which is proven to cause a significant reduction in blood loss, blood transfusion, and reduced hospital stay when compared to traditional TURP (6).