The Zenflow Spring System EU Safety and Performance Study

The objectives of the trial are to demonstrate the safety and performance of the Zenflow Spring System in relieving the symptoms of obstructive Benign Prostatic Hyperplasia (BPH).

A multi-center, prospective, single arm safety and performance trial. Subjects will be treated either in the Investigator's out-patient treatment room or in the OR, with local anaesthesia only. All subjects will be followed for the entire duration of the study until exit after the 60 month follow-up visit.

Eligibility Criteria:
Inclusion Criteria:

1. Patient is able and willing to comply with all the assessments of the study
2. Patient or patient's legal representative has been informed of the nature of the study, agrees to participate and has signed the informed consent form
3. ≥ 45 years of age
4. Baseline IPSS score \> 13, and a baseline Quality of Life (QoL) question score \> 3
5. Prostate volume 25 - 80 cc by Trans Rectal Ultrasound (TRUS) or abdominal ultrasound, measured within past 90 days and prostatic urethral length between 2.5- 4.5 cm
6. Failed, intolerant, or patient choice to not take a medication regimen for the treatment of LUTS
7. Patient must meet ONE of the following criteria:

   1. Baseline PSA \<= 2.5ng/mL
   2. Baseline PSA \>2.5 ng/mL and \<=10 ng/mL AND free PSA \>=25% of total PSA (no biopsy required or negative biopsy)
   3. Baseline PSA \>10ng/mL AND negative prostate biopsy1 result within 12 months
   4. Negative prostate biopsy1 within 12 months if abnormal digital rectal examination
   5. 3 Tesla MRI of the prostate, with normal findings, within 12 months prior to the baseline visit

Exclusion Criteria:

1. Obstructive intravesical median prostatic lobe which, in the opinion of the Investigator, would not benefit from treatment
2. Urethral stricture, meatal stenosis, or bladder neck obstruction - either current, or recurrent requiring 2 or more dilations as reported in the patient's history
3. Requiring self-catheterization to void
4. Baseline PSA \> 10 ng/mL or confirmed or suspected prostate cancer
5. Any of the following, taken from a single uroflowmetry reading:

   1. Peak urinary flow rate \> 12 ml/second
   2. Post-void residual (PVR) \> 250 ml
   3. Peak Urinary flow rate of \> 15 ml/second
   4. \< 125ml urinary volume voided at baseline (pre-bladder urinary volume of ≥ 150 ml required)
6. Other condition or disease that might cause urinary retention
7. History of other diseases causing voiding dysfunction
8. Concomitant Urinary Tract Infection (UTI) (subject can be enrolled following successful treatment of UTI and a clean urine test), or a history of recurrent or chronic UTIs (defined as 2 or more UTIs in the past 12 months)
9. Concomitant bladder stones
10. Previous pelvic irradiation or radical pelvic surgery
11. Previous prostate surgery, stent implantations, laser prostatectomy, hyperthermia or another invasive treatment to the prostate
12. Chronic prostatitis, or recurring prostatitis within the past 12 months
13. Known allergy to nickel
14. Life expectancy less than 24 months
15. Use of concomitant medications (e.g., anticholinergics, antispasmodics or antidepressants) affecting bladder function
16. Inability to stop taking anticoagulants and/or antiplatelets for at least 3 days prior to the procedure or coumadin for at least 5 days prior to the procedure (low dose aspirin therapy not prohibited)
17. Taking 5-alpha reductase inhibitors within 3 months of pre-treatment (baseline) 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 throughout the study)
18. Taking one of the following within 2 weeks of pre-treatment (baseline) evaluation:

    1. alpha-blockers,
    2. androgens,
    3. anticholinergics, or
    4. cholinergic medication gonadotropin releasing hormonal analogs
19. Taking one of the following within 24 hours of pre-treatment (baseline) evaluation:

    1. phenylephrine, or
    2. pseudoephedrine
20. Future fertility concerns
21. Any severe illness that might prevent study completion or would confound study results