Historical development of HoLEP
The holmium:YAG laser (2140 nm) acts through a predominantly photothermal mechanism.[
5] Because it is capable of vaporizing soft tissue, application of the holmium laser for BPH first focused on sequential ablation of tissue in order to enlarge a channel through the prostate. Initially, treatment with the holmium laser was performed in association with the neodymium (Nd:YAG) laser, in a technique known as combination endoscopic laser ablation of the prostate (CELAP)[
6] It was hoped that the holmium laser would be able to reduce the short-term sequelae of Nd:YAG coagulation prostatectomy, which included prolonged catheterization and delayed symptomatic improvement [
7]
With CELAP, a circumferential coagulation of prostatic tissue was first performed using the Nd:YAG laser, followed by vaporization of an adequately sized channel using holmium energy. Unfortunately, this combination procedure was still associated with significant indwelling catheterization times postoperatively, ranging from 4.1 to 7.1 days.[
6,
8] In addition, many patients required re-catheterization for urinary retention and also had irritative voiding symptoms[
4,
9]
As more clinical experience with the holmium laser was gained, it became apparent that the laser had sufficient hemostatic effects when used to vaporize soft tissue on its own, without the addition of the Nd:YAG component[
4] Further evidence of the effectiveness of the holmium laser on prostate tissue was provided by canine and human studies by Kabalin, who showed that hemostatic vaporization occurred using high powers ranging from 50 to 80 watts[
10,
11] As a result, holmium laser ablation of the prostate, termed HoLAP, was developed, which eliminated many of the short-term voiding problems associated with use of the Nd:YAG laser.
The main advantage of HoLAP was the ease in learning the procedure. One disadvantage, however, was the lack of tissue availability for pathologic analysis. In addition, the procedure was considered cumbersome, mainly because of the slow process of tissue vaporization. In a randomized comparison of holmium vaporization versus TURP, Mottet, et al, showed that the laser procedure required a significantly longer time (75 vs. 56 minutes) to achieve prostatic defects comparable to those in the TURP patients[
12] For this reason, HoLAP was considered useful only for smaller glands. In order to achieve more efficiency, attention then turned to developing a method of removing larger portions of adenoma.
The first description of holmium laser resection of the prostate (HoLRP) was reported by Gilling, et al in 1996[
13] This technique was the first to utilize the cutting properties of the holmium laser to detach large sections of adenoma tissue. A major advantage is that normal saline could be used as the irrigation fluid, which eliminates the risk of TUR syndrome during resection. During a HoLRP, the median lobe is resected first, followed by the lateral lobes. Because tissue needs to be retrieved endoscopically, the lobes are divided into manageable pieces while being freed from the surgical capsule. Larger fragments are then recovered from within the bladder using a modified resectoscope loop that engages and holds the tissue against the resectoscope sheath, while smaller fragments can be removed using an Ellik evacuator.
Many centers have published HoLRP series with favorable results [
13‐
20] In all of these series, no patients required transfusions or developed dilutional hyponatremia. In a randomized trial comparing HoLRP to TURP with two year follow-up data, there were no significant differences in AUA symptom scores, quality of life scores, peak flow rates, or complications; however, TURP patients had significantly longer mean catheterization times and hospital stays[
15]
Operative time remains an issue for HoLRP, with TURP being completed at significantly faster rates[
16] One issue contributing to the overall length of the procedure is the retrieval of the resected tissue. First of all, the size of the tissue fragments is limited by the urethral caliber. In addition, the resectoscope must be removed in its entirety each time a fragment is removed, thus slowing the process. Questions have also been raised about the ability to obtain accurate pathologic diagnoses with HoLRP, citing an abundance of cauterization artifact from analyzed specimens[
21]
In order to address the previous concerns with HoLRP, a prototype transurethral tissue morcellator was devised by Fraundorfer and Gilling.[
22] By morcellating tissue within the bladder, the resection technique could be modified to allow complete enucleation of the median and lateral lobes of the bladder, without the time-consuming process of tailoring the lobes into manageable fragments. This enables the surgeon to achieve a degree of tissue removal approximating that of an open simple prostatectomy while maintaining a minimally invasive nature. As such, the latest modification of the holmium resection technique is now known as holmium laser enucleation of the prostate (HoLEP), combined with mechanical morcellation. HoLEP can be utilized for virtually any BPH configuration or size. Further, concomitant bladder calculi, if present, are easily vaporized by the holmium laser at the time of HoLEP. Using this technique, even the largest of glands can be safely enucleated, with superior results when compared to the alternative approach of open simple prostatectomy[
23]. A summary of the published HoLEP results are detailed in table
1.
Currently, we use HoLEP exclusively in our respective institutions for the surgical treatment of BPH. The following is a description of our HoLEP technique, detailing the pre-operative work-up, necessary equipment, and stepwise breakdown of the procedure.