This is a clinical evaluation to assess the safety and performance of the Zenflow Spring System when used as intended to relieve symptoms of obstructive Benign Prostatic Hyperplasia (BPH).

A multi-center, prospective, single arm safety, performance, and effectiveness trial. The study will be conducted in two stages. Upon the successful completion of stage 1, the study will be expanded and continue to stage 2.

Stage 1 will enroll subjects in the Intent to Treat (ITT) cohort. The purpose of stage 1 is to assess acute safety and performance of the Zenflow System at the time of the procedure, through discharge, 2 weeks and 1 month, in up to 10 subjects enrolled at up to 7 investigational sites, to determine continuation to stage 2.

Upon successful completion of stage 1, the study will be expanded to stage 2 with sites added and continued enrollment in the ITT cohort. All subjects, including those enrolled in the stage 1 evaluation, will continue to be followed at all the designated follow-up time points for the full duration of the study (60 months).

Whether or not the study continues to Stage 2, all enrolled subjects will be followed for the entire duration of the study (60 months), or until exited.

Inclusion Criteria:

All subjects are required to meet the following inclusion criteria in order to be considered eligible for participation in this trial:

1. ≥ 45 years of age
2. Baseline IPSS score > 13, and a baseline Quality of Life (QoL) question score > 3
3. Prostate volume 25 - 80 cc by Trans Rectal Ultrasound (TRUS), measured within past 90 days and prostatic urethral length between 2.5-4.5 cm.
4. Failed or intolerant to medication regimen for the treatment of LUTS.

Exclusion Criteria:

Subjects will be excluded from participating in this trial if they meet any of the following criteria:

1. Obstructive intravesical median prostatic lobe or high bladder neck
2. Urethral stricture, meatal stenosis, or bladder neck obstruction - either current, or recurrent requiring 2 or more dilatations
3. Baseline PSA > 10 ng/mL or confirmed or suspected prostate cancer
4. Elevated risk of prostate cancer
5. Post-void residual volume (PVR) > 250 ml
6. Peak urinary flow rate > 12 ml/second, with ≥ 125 ml voided volume at baseline
7. History of chronic urinary retention
8. History of neurogenic bladder
9. Compromised renal function (e.g., serum creatinine > 1.8 mg/dl) due to bladder obstruction
10. Concomitant Urinary Tract Infection (UTI) (subject can be enrolled following successful treatment of UTI and a clean urine test)
11. Concomitant bladder stones
12. Confirmed or suspected bladder cancer
13. Previous pelvic irradiation or radical pelvic surgery
14. Previous prostate surgery, stent implantations, laser prostatectomy, hyperthermia or another invasive treatment to the prostate
15. Chronic prostatitis, or recurring prostatitis within the past 12 months
16. Serious concurrent medical conditions such as uncontrolled diabetes
17. Known allergy to nickel
18. Life expectancy less than 24 months
19. Use of concomitant medications (e.g., anticholinergics, antispasmodics or antidepressants) affecting bladder function
20. Patients taking coumadin 3 days or less prior to procedure and have INR value > 1.5 on day of procedure. ASA and clopidogrel must be ceased 7 days prior to the procedure
21. 5 alpha reductase inhibitors within 6 months of pre-treatment evaluation unless evidence of same drug dose for at least 6 months with a stable voiding pattern (the drug dose should not be altered or discontinued for entrance into or throughout the study)
22. alpha blockers within 2 weeks of pre-treatment evaluation unless evidence of same drug dose for at least 6 months with a stable voiding pattern (the drug dose should not be altered or discontinued for entrance into or throughout the study)
23. Future fertility concerns
24. Any severe illness that might prevent study completion or would confound study results