What Is Non-Obstructive Urinary Retention?

Urinary retention means the bladder does not empty the way it should — you may be unable to urinate, empty only partially, or feel like the bladder is never quite empty. In non-obstructive retention, this happens even though there is no physical blockage (no enlarged prostate, no urethral stricture, no stone) standing in the way.

Instead, the problem is in the signaling and coordination between the bladder and the nerves that control it. The bladder muscle may be underactive, or the muscles that hold urine in may not relax at the right time, so the bladder can't empty effectively.

Obstructive vs. Non-Obstructive Retention

Obstructive retention is caused by something physically blocking urine flow (such as an enlarged prostate or a stricture) and is treated by relieving that blockage. Non-obstructive retention has no blockage to remove — so it calls for a different approach, like restoring the nerve signals that drive bladder emptying. InterStim is designed for this non-obstructive type.

Many people with non-obstructive retention manage day to day with clean intermittent catheterization (CIC) — using a catheter to drain the bladder. InterStim offers a way to address the underlying signaling problem so that catheterization may be reduced or no longer needed.

Who Is a Candidate?

May Be a Good Candidate

  • Confirmed non-obstructive retention — testing shows no blockage
  • Reliance on catheterization to empty the bladder
  • Retention that hasn't improved with conservative measures or medications
  • No nerve disorder that severely affects bladder control
  • Able to take part in the trial phase and operate the device

May Not Be Ideal For

  • Retention caused by a physical blockage (e.g., enlarged prostate or stricture) — this must be treated first
  • Certain progressive neurological conditions
  • Active, untreated urinary tract infection
  • Inability to follow up or manage device settings

A careful evaluation — including a check that the bladder outlet is not blocked — confirms whether non-obstructive retention is the cause and whether InterStim is a good fit.

How InterStim Helps

Normal bladder emptying depends on a steady conversation between your bladder, your spinal cord, and your brain, carried by the sacral nerves at the base of the spine. In non-obstructive retention, these signals are out of sync, so the bladder doesn't get the message to empty — or the muscles that should relax stay tight.

Sacral neuromodulation (SNM) — delivered by the InterStim device — sends gentle electrical pulses to the sacral nerves. This helps normalize the signaling so the bladder and pelvic floor work together more effectively, allowing more complete emptying. Because it works on the nerve signals themselves, InterStim addresses the functional root cause rather than just the symptoms.

InterStim is also widely used for overactive bladder and urge incontinence. If you'd like the broader overview of the therapy, see our guide to InterStim for overactive bladder.

The Two-Step Process: Trial, Then Implant

A key advantage of InterStim is that you test it first. You only move to a permanent implant if the trial clearly helps.

Step 1: Test Phase

  • A temporary device is placed to stimulate the sacral nerve during a brief procedure
  • You wear it for 3–14 days while tracking how well you empty your bladder and how often you need to catheterize
  • A clear improvement is a green light to proceed

Step 2: Long-Term Implant

  • If the trial is successful, a small permanent device is implanted under the skin, typically near the upper buttock
  • It is a short outpatient procedure
  • Settings are adjustable and the therapy is reversible
  • Most patients resume normal activity quickly

Benefits of InterStim for Retention

  • More complete bladder emptying with less reliance on catheters — and, for some, no catheter at all
  • Improved quality of life and confidence in daily activities
  • Minimally invasive and reversible — the device can be turned off or removed
  • Patient-tested before commitment — the trial confirms benefit first
  • Durable relief reported over the long term in many patients

Is It Safe?

  • InterStim has a strong safety profile with decades of clinical use.
  • Most side effects are minor — such as discomfort near the implant site or temporary changes in stimulation.
  • Newer device versions and surgical techniques have further reduced complications.

What to Expect

Before the Trial

  • Evaluation to confirm non-obstructive retention and rule out a blockage
  • Review of your catheterization routine and symptoms

During the Trial & Implant

  • Brief, minimally invasive procedures performed on an outpatient basis
  • You track bladder emptying to measure how well the therapy works

After the Implant

  • Settings are fine-tuned to your needs and can be adjusted over time
  • Ongoing follow-up to confirm lasting benefit

Frequently Asked Questions

How is this different from retention caused by an enlarged prostate?

An enlarged prostate (or a stricture) is a physical blockage — that's obstructive retention, and it's treated by relieving the blockage. InterStim is for non-obstructive retention, where there is no blockage but the bladder still won't empty. Your evaluation determines which type you have.

Will I be able to stop using a catheter?

Many patients significantly reduce — and some eliminate — the need for catheterization after successful therapy. The trial phase helps predict your personal result before you commit to an implant.

What happens during the trial?

A temporary lead is placed to stimulate the sacral nerve. You go home and track your bladder emptying for several days. If you see meaningful improvement, you may opt for a long-term implant.

Is the implant reversible?

Yes. The therapy is adjustable, and the device can be turned off or removed if needed.

Empty More Naturally — With Fewer Catheters

If you're living with urinary retention and no blockage can be found, InterStim may help your bladder empty on its own again. Our team confirms the cause, guides you through a low-risk trial, and supports you from evaluation through long-term care.

  • ✅ Evaluation to confirm non-obstructive retention
  • ✅ Test the therapy before committing to an implant
  • ✅ Reduce or eliminate the need for catheterization
  • ✅ Minimally invasive, adjustable, and reversible
Schedule Your Consultation

Call 678-344-8900 to speak with our team