Anatomic considerations for the prostatic urethral lift procedure

Histologic BPH develops within the transition zone of the prostate, which represents a region around the prostatic urethra that gradually enlarges to compress the urethral lumen. Although the exact cause of the pathologic enlargement is incompletely understood it likely involves inherited genetic factors, hormonal dysregulation, and ongoing inflammation that induces the release of proliferative mediators [15]. Urodynamic testing has identified urethral obstruction secondary to both compression by the enlarged prostate as well as a constrictive component that may be related to specific tissue factors such as fibrosis [16]. Traditional extirpative interventions all involve a reduction in the prostate volume (directly with resection or indirectly with thermal ablation) that creates a more open prostatic urethral lumen with clear demonstration of improved voiding parameters. It is the associated toxicity of these procedures that has created a clinical need for a novel therapeutic approach.

The PUL technique using the UroLift implant system is conceptually designed to also create a more open prostatic urethral lumen that can overcome both the compressive and constrictive aspects of BPH. The stromal capsule that surrounds the prostate gland is strong, while the prostatic parenchyma is sponge‐like and able to be compressed. The placement of a transprostatic implant between the capsule and the urethral urothelium can compress the intervening parenchyma and create an open lumen.

The specific location for placement of the implants is designed to avoid injury to the bladder neck, ejaculatory ducts, posterolateral neurovascular structures, and the rectum. The prostatic parenchyma is compressed in an anterior and lateral direction that creates an open anterior channel through the prostatic lumen.

Equipment

The PUL procedure has been designed as an endoscopic technique that can be performed under a variety of anesthesia conditions. The equipment includes a 20 Fr rigid cystoscope with a 2.5 mm 0° endoscope (currently manufactured by Karl Storz, Tuttlingen, Germany) with a longer custom bridge that allows direct visual placement of the cystoscope into a man’s bladder.

The permanent UroLift implant consists of a nitinol capsular tab attached to an adjustable length of polyethylene terephthalate (PET) monofilament that traverses the prostatic parenchyma. The inner urethral endpiece is constructed of stainless steel and is applied to the appropriately tensioned PET suture. The delivery system is currently a single‐use device that contains all components of one implant and is delivered through a spring‐loaded 19 gauge needle under direct endoscopic guidance. The 0° endoscope is inserted through each individual delivery device. A photograph of the equipment is provided in Figure 148.1.

Surgical indications for the prostatic urethral lift

The majority of men who are candidates for treatment of LUTS secondary to BPH with the PUL procedure will have suffered from bothersome voiding symptoms for a prolonged period of time and may have developed evidence of bladder wall thickening or trabeculation that can be seen on diagnostic cystoscopy or pelvic ultrasound [17]. Since the treatment of BPH‐related LUTS with medications has been codified into various guidelines it is likely that most men will also have taken and failed the standard options of an alpha‐adrenergic antagonist or a 5‐alpha reductase inhibitor [18]. Therefore, it is expected that the predominant surgical indication for performing a PUL will be bothersome LUTS that have not responded to medical management. There may also be individuals who have suffered intolerable toxicity from medical therapy or who have contemporaneous medical contraindications for such treatment. Interestingly, the PUL procedure may also be an appropriate choice for men on chronic anticoagulation when this therapy is unable to be safely halted for surgery. Finally, there are likely to be some healthy men with a predictably long life expectancy for whom the palliative treatment with medications provides an inadequate long‐term approach to maintaining a healthy bladder.

The preoperative evaluation for a man with bothersome LUTS should be guided by established approaches as outlined in the published guidelines [19]. Although a diagnostic cystoscopy is not required for all men who have elected treatment for LUTS this test can be helpful in determining the optimal candidate for the PUL [20]. A transrectal or suprapubic pelvic ultrasound can also provide useful information about prostatic anatomy, prostate volume and the presence of a middle lobe that could alter the surgical approach [21, 22]. Current selection criteria for men as candidates for the PUL likely mirror, but not exclusively, the inclusion criteria for the L.I.F.T. randomized placebo‐controlled clinical trial that resulted in the US Food and Drug Administration (FDA) approval for the UroLift implant device [23]. These criteria included men over the age of 50 with an American Urological Association Symptom Index (AUA‐SI) (equivalent to the International Prostate Symptom Score or IPSS) greater than 13 and a maximum urinary flow rate of ≤12 ml/s. In addition, the optimal candidate should have a measured or estimated prostate volume between 30 and 80 cm³ without a visually obstructing middle lobe.

It is also worth considering other potential indications for performing a PUL in an individual with BPH‐related voiding dysfunction. The procedure can be performed under local anesthesia or intravenous sedation making this approach appropriate for medically compromised or frail elderly men who could not otherwise tolerate a bladder outlet surgery. In addition, anecdotal clinical experience has demonstrated that UroLift implants can be deployed safely in men on anticoagulation therapy with only mild hematuria.

Perhaps another common indication is a healthy man who selects the PUL approach in an effort to avoid the risk of sexual dysfunction that has been associated with other bladder outlet procedures. In particular, the creation of an open prostatic urethral channel with the UroLift implants system has been associated with stable or improved erectile function as well as improved ejaculatory function in several clinical investigations [24].

Surgical technique

The endoscopic technique for PUL is designed to allow the customized placement of each individual implant according to the anatomy of the lateral lobes of the prostate. A cartoon depiction of the surgical approach is provided in Figure 148.2. The spring‐loaded needle is of adequate length to perforate through the prostatic parenchyma in an anterior and lateral position to deploy the capsular tab on the external prostatic capsule. The length of the PET monofilament is determined relative to the thickness of the prostatic tissue by compressing the prostatic tissue with the tip of the delivery device. Finally, the inner urethral endpiece is secured to the tensioned monofilament in such a manner that it results in the invagination of the stainless‐steel endpiece into the urethral wall. The inert endpiece is rapidly covered by the urothelium within the prostatic urethra, preventing exposure of the device to urine. The specific details of the procedure have been well described by McNicholas et al. in 2013 and will be briefly reviewed again in this chapter [25].

The endoscopic technique is performed on an appropriately anesthetized man (either with local lidocaine urethral anesthetic or with intravenous sedation) positioned in the routine dorsal lithotomy position. The most effective anesthetic approach is best determined by the skillset of the treating urologist and the preferences or medical requirements of the patient.

The rigid cystoscope is advanced into the bladder under direct vision using the custom bridge with care taken to avoid urothelial injury that could result in unnecessary bleeding. The care taken in this portion of the surgery can avoid the delays in treatment that would be associated with diminished visualization due to bleeding. The treating urologist will need to evaluate the prostatic anatomy and develop a treatment plan for positioning the individual implants on both sides of the prostate into the anterior and lateral prostatic urethral walls. The endoscopic lens is then placed into the UroLift device, which is subsequently inserted into the rigid cystoscopic sheath and into the bladder. Since the active end of the device protrudes approximately 2 cm beyond the end of the cystoscope, care must be taken to avoid injuring the bladder wall.

The device is then turned 90° to the right or left side and withdrawn into the prostatic urethral lumen. The initial pair of implants is often placed in the proximal urethral lumen approximately 1.5 cm distal to the bladder neck. The device is not activated until the specific location for the implant has been determined. The prostatic tissue is compressed approximately 20° from the midline with the tip of the device. The initial compression may have been positioned at the 9 o’clock location on the right side (or 3 o’clock on the left side) but upward pressure is required to create the anterior lift that will ultimately result in an open anterior channel. Once adequately compressed and lifted, the device is activated and the needle advanced to deploy the capsular tab.

The blue PET suture will be visible within a small window in the tip of the device. The tip of the cystoscope is then advanced slowly toward the bladder, creating a tension on the suture. A white reflection on the blue suture will come into view through the small window once adequate tension has been applied and the luminal endpiece can then be deployed. The device applies the endpiece and cuts the suture simultaneously. This causes the endpiece to visually invaginate into the urethral wall. The implant procedure is then repeated as often as needed to create an open channel from the bladder to the veru montanum. In the L.I.F.T. trial the median number of implants required was 4.9 with a range of 2–11 [23]. Routine clinical practice has resulted in a range of 2–8 implants with the total determined by the individual prostate anatomy.

The procedure is determined as complete when a surveillance cystoscopic examination reveals an open anterior urethral channel without any urethral endpieces visible within the bladder lumen. Any of the endpieces that were inadvertently placed into the bladder lumen at the bladder neck can be easily removed with a flexible grasper. The PET suture will retract into the prostatic parenchyma. The man can then be discharged home either with or without a urethral catheter as consistent with the practice pattern of the treating urologist. The large majority of men will not require a catheter after this surgery.

Prostatic urethral lift clinical outcomes

Woo and colleagues first reported in 2011 on the technical feasibility and safety of the PUL procedure in men [26]. This preliminary clinical investigation involved 19 men who received the implants under general anesthesia with two versions of the delivery device. All procedures were completed satisfactorily with no serious device‐ or procedure‐related adverse events. Subsequently the delivery device has been standardized as a 20 Fr system and procedures have been performed under all forms of anesthesia including local instillation of lidocaine.

A prospective randomized and sham surgery controlled investigation, called the L.I.F.T. Study, was published in 2013 and provided the foundation for ultimate FDA approval of the UroLift device in the United States [23]. A total of 206 men were randomized to either the sham procedure or the PUL with the UroLift implants using a primary endpoint of comparison of the AUA‐SI score at three months. Ultimately, this revealed a reduction in the AUA‐SI of 11.1 ± 7.67 points in the PUL group compared to an initial reduction of 5.9 ± 7.66 points in the sham group (P = 0.003). A recent publication has compared the clinical outcomes at 2 years in the men who crossed over to the PUL procedure at six months following a sham treatment. In this analysis each man served as his own control and demonstrated a persistent 36% improvement in the AUA‐SI from baseline. In addition, other endpoints – quality‐of‐life score (QOL), BPH Impact Index (BPHII), and maximum urinary flow rate – improved 40%, 54%, and 77% from baseline, respectively [27].

Subsequent to the initial publications there have been a number of prospective clinical trials that have detailed the favorable clinical outcomes of this new procedure [28–30]. Table 148.1 provides an overview of these outcomes.

Although the PUL has demonstrated high‐quality outcomes in the context of voiding symptoms it was really the potential to reduce toxicity that was the compelling factor in the development of this new approach. The more established interventions for benign prostatic enlargement include the transurethral resection of the prostate (TURP), various laser‐based extirpative approaches and thermal ablative techniques designed to reduce the volume of prostatic tissue that obstructs the bladder outlet. Each of these approaches demonstrates effective reduction of bothersome voiding symptoms but is associated with side‐effects that likely cause men to delay or avoid altogether any beneficial therapy. The potential adverse consequences include incomplete resection with the need for repeat interventions, urinary tract infection, urethral stricture, incontinence, and sexual dysfunction. A thorough analysis of the risk for toxicity with each treatment strategy is beyond the intent of this review but several publications may be informative to the interested individual [31–35].

The mechanical principle of the PUL procedure is to endoscopically place a transurethral implant that compresses the prostatic parenchyma to create a more open urethral channel. This can be accomplished with a very favorable toxicity profile when compared to the established extirpative approaches mentioned above. Sonksen and colleagues published a multicenter prospective randomized comparison of the PUL to the TURP in 2015 using a novel composite endpoint measurement called the BPH6. This tool combined measurements of six domains in order to assess overall outcome from each procedure. These domains included LUTS relief, recovery experience, erectile function, ejaculatory function, continence preservation, and safety. A total of 80 men (45 PUL and 35 TURP) were evaluated at 12 months with the PUL found to be noninferior to the TURP [36]. The transurethral resection was superior in achieving a reduction in LUTS but the overall outcome was superior for the PUL. Importantly, there was no statistical difference in the incidence of Clavien–Dindo grade 1, 2, or 3 adverse events between the two approaches. However, urinary incontinence, retrograde ejaculation and urethral stricture were significantly more common in the TURP group. Erectile dysfunction was also more common in the TURP group but the difference did not reach statistical significance.

The information regarding sexual function following a prostate‐directed surgery continues to suggest that men consider these risks when making a decision to receive a bladder outlet procedure. Although the risk of erectile dysfunction is small following the extirpative procedures, other sexual dysfunction, such as loss of ejaculatory function, are significantly more common [37]. McVary and investigators for the L.I.F.T. trial reviewed the outcomes for sexual dysfunction using the Sexual Health Inventory for Men (SHIM) and the Male Sexual Health Questionnaire for Ejaculatory Dysfunction (MSHG‐EjD) [24]. There was no evidence for a negative effect of the PUL on erectile function. In fact, the 12‐month SHIM analysis revealed a statistically significant improvement in erectile function for the men who reported severe erectile dysfunction at baseline. In addition, men reported a 40% reduction in an ejaculatory bother score by the 12 months endpoint of the study. These reports establish the PUL as the only surgical procedure for BPH that can improve ejaculatory function while minimizing any negative effect on erectile function.

Overall, the current clinical experience with the PUL procedure has revealed the technique to be well tolerated with only mild toxicity. Box 148.1 lists the adverse events that were identified during the L.I.F.T. randomized trial. The likely unique adverse event that has been identified with the UroLift implants is encrustation of the urethral endpiece. This was identified during the randomized trial in 2.1% (14 out of 642 total implants). Only those implants with the urethral endpiece inadvertently positioned within the bladder lumen at the bladder neck are at risk for this toxicity. None of the correctly placed devices were found to encrust and the involved endpiece could be easily removed endoscopically with a flexible grasper.