Water vapor thermal therapy (Rezum) is a minimally invasive treatment for benign prostatic hyperplasia (BPH) that uses injections of sterile water vapor directly into the prostate for tissue ablation. Although Rezum is currently indicated for use in men with prostate sizes ≥30 and ≤80 ml, the guidelines offer no recommendation with regards to Rezum therapy for those with large-volume glands.

For prostates larger than 80ml, open or transurethral anatomical enucleation is recommended. Open prostatectomy has a higher risk of bleeding and slower postoperative recovery, with a higher probability of requiring blood transfusion. The incidence of urinary incontinence after transurethral enucleation ranges from 3.33% to 20%, possibly due to excessive traction and compression on the external urethral sphincter, leading to partial muscle fiber rupture. The rate of erectile dysfunction after enucleation is 8.82%, while retrograde ejaculation occurs in 6.37% of cases, especially for patients with larger prostates. Once these complications occur, they are often difficult to recover from and severely impact the patient's quality of life. In our center, the technique of Rezum has been further improved by incorporating ultrasound and MRI imaging guidance. The investigators design a reasonable and comprehensive ablation plan that ensures accurate positioning of enlarged prostate glands for complete and thorough ablation while ensuring efficacy and safety.

Inclusion Criteria:

1. Male subjects ≥ 45 years of age who have obstructive symptoms secondary to BPH requiring invasive intervention.
2. IPSS score of ≥ 13.
3. Qmax: Peak flow rate ≤ 15 ml/sec.
4. Post-void residual (PVR) < 300 ml.
5. Prostate volume between 80 to 120 ml.
6. Subject able to complete the study protocol in the opinion of the Principal Investigator.

Exclusion Criteria:

1. History of any illness or surgery that in the opinion of the Principal Investigator may confound the results of the study.
2. Any prior minimally invasive intervention or surgical intervention for the symptoms of BPH.
3. Currently enrolled in another clinical trial.
4. Confirmed or suspected malignancy of prostate or bladder.
5. Documented active urinary tract infection by culture or bacterial prostatitis.
6. Neurogenic bladder or sphincter abnormalities.
7. Urethral strictures, bladder neck contracture or muscle spasms.
8. Bleeding disorder (note that use of anti-platelet medication is not an exclusion criterion).
9. Subjects who are interested in maintaining fertility.
10. Significant urge incontinence.
11. Unable or unwilling to sign the Informed Consent Form.
12. Any cognitive disorder that interferes with or precludes a subject from directly and accurately communicating with the Principal Investigator regarding the study.