Urethral Stricture: Why the Stream Weakens, and Why Repeat Dilatation Is Not the Answer

最終更新日： 8月 27, 2026

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A urethral stricture is a scarred, narrowed segment of the tube that carries urine out of the bladder. It affects roughly one man in a hundred and becomes considerably commoner after 65. Women are affected far more rarely.

The symptoms are unremarkable — a stream that has been getting weaker, hesitancy, straining, dribbling afterwards, sometimes repeated infections — and they look exactly like an enlarged prostate, which is why strictures are often treated as BPH for years before anyone looks. A younger man with a poor stream, or any man with a history of catheterisation, endoscopic surgery, urethral infection or pelvic injury, deserves the stricture question asked directly.

• 泌尿器センター バンコク病院 タイ オンライン予約 02-310-3009 bhquro@bdms.co.th
• サミティジ・シラチャ病院 チョンブリ 088-022-1445

Symptoms that need attention the same day

These were absent from the earlier version of this page. In an emergency in Thailand, call 1669.

• Complete inability to pass urine with a painful full bladder — see 急性尿閉. A stricture is one of the reasons a catheter cannot always simply be passed, which is why this needs a urologist rather than repeated attempts.
• Fever with difficulty passing urine, or with pain in the perineum.
• A tender, swollen, red area in the perineum or scrotum — infection can track outside the urethra and that is a surgical emergency.
• Visible blood with clots, or a stream that has stopped abruptly rather than weakened gradually.

Where strictures come from

1. No identifiable cause, about a third. Commoner in younger men, and thought to represent childhood injury nobody remembers or a subtle congenital narrowing.
2. Caused by medical treatment, about a third — previous endoscopic surgery through the urethra, or a catheter left in for a long period. This is the group worth pausing on, because it is the preventable one: an unnecessary catheter, or one left longer than needed, can cost a man his stream years later.
3. 炎症性, roughly one in six — following urethral infection, classically untreated gonorrhoea. A separate skin condition, lichen sclerosus, scars the opening and the front of the urethra and behaves differently from other strictures; it needs recognising because it changes what tissue can be used to repair it.
4. 外傷性, about one in five — a straddle injury, a pelvic fracture, or a penile fracture.

Whatever the cause, the healing response lays down scar, and scar contracts. That is why the narrowing develops slowly over months or years rather than at the time of the injury.

How it is confirmed

• A flow test, which is quick and non-invasive. The shape of the trace is informative — a stricture classically produces a long flat plateau rather than the usual bell curve.
• 軟性膀胱鏡検査 to see the narrowing directly.
• A contrast study of the urethra, which does the thing cystoscopy cannot: it shows how long the stricture is and exactly where it sits. Since length and site determine the operation, this is what turns a diagnosis into a plan.

Treatment — and the point the earlier version left out

The earlier version listed the options with their recurrence rates and described dilatation as giving results comparable to surgery. Two corrections, and the second is the important one.

• Dilatation — stretching the narrowed segment. Quick, minor, and around six in ten strictures are back within four years.
• Internal urethrotomy — cutting the stricture endoscopically, with a blade or a laser. About half are back within four years, and the two techniques perform similarly.
• 尿道形成術 — open reconstruction, removing the scarred segment and rejoining the urethra, or patching it with a graft, usually taken from the inside of the cheek. Much the most durable option, and the only one that is genuinely curative.
• Intermittent self-catheterisation, absent from the earlier version — passing a catheter yourself periodically to keep the channel open. Not a cure, and a reasonable arrangement for a man not suited to reconstruction.

Why repeating the simple procedure is the wrong plan

Dilatation and urethrotomy are holding measures, not treatments — describing their results as comparable to surgery understates a real difference, since half to six in ten fail within four years while reconstruction largely does not.

More importantly: if a stricture has already recurred after one endoscopic treatment, a second attempt at the same thing has a very low chance of lasting cure. And each cut or stretch adds scar, lengthening the diseased segment and making the eventual reconstruction harder and less likely to succeed.

The practical rule this page now states plainly: a man facing a third dilatation should be having a conversation about reconstruction instead. Men are commonly dilated repeatedly over years without anyone offering the alternative, and by the time it is discussed the operation is more difficult than it needed to be. Urethroplasty is a bigger undertaking, and it is not reserved for strictures over a certain length — a failed endoscopic treatment is itself a reason to consider it.

What happens if it is left

Also absent from the earlier version, and the reason a weak stream is not something to live with indefinitely.

The bladder compensates by pushing harder, and over years that thickened, overworked muscle can lose its ability to empty — a change that does not always reverse once the stricture is fixed. Downstream of that come recurrent infections, bladder stones, retention, and eventually pressure on the kidneys. The stricture is easy to fix; a bladder that has given up is not.

Recurrence is possible after any treatment because the underlying process is scarring, so follow-up — a periodic flow test rather than waiting for symptoms — is part of the management rather than an optional extra.

尿道狭窄に関するよくある質問

尿道狭窄の原因は何ですか？

Scarring of the urethral wall. About a third have no identifiable cause, a third follow medical treatment such as endoscopic surgery or prolonged catheterisation, roughly one in six follow urethral infection, and about one in five follow injury — a straddle injury, pelvic fracture or penile fracture. Lichen sclerosus is a distinct skin condition affecting the opening and needs recognising separately.

I have had a dilatation before and it has come back. Should I have another?

Probably not. A repeat endoscopic treatment after a first has failed has a very low chance of lasting cure, and each attempt adds scar, lengthening the stricture and making reconstruction harder later. A man facing a third dilatation should be discussing urethroplasty instead.

Which treatment lasts longest?

Urethroplasty, by a wide margin — it is the only genuinely curative option. Dilatation recurs in about six in ten within four years and urethrotomy in about half. Describing them as comparable to surgery, as an earlier version of this article did, understates the difference.

Could my weak stream be the prostate rather than a stricture?

It could, and the two are frequently confused because the symptoms are identical. A flow test, cystoscopy and a contrast study distinguish them. Be particularly suspicious of a stricture if you are relatively young, or have had a catheter, endoscopic surgery, a urethral infection or a pelvic injury.

What happens if I just live with it?

The bladder works harder to overcome the obstruction and can eventually lose the ability to empty, which does not always reverse after the stricture is repaired. Recurrent infections, bladder stones, retention and pressure on the kidneys follow. The stricture is easier to fix than the bladder damage it causes.

相談の手続きをする

Dr. Soarawee Weerasopone sees patients at バンコク病院本部 そしてチョンブリー県のサミティベート・シーラチャ病院にて 088-022-1445. Bring details of every previous dilatation or urethrotomy with dates, and any earlier flow tests or contrast studies — the number of previous treatments is one of the things that most affects what is offered next.

バンコク病院の遠隔医療は、来院が困難な患者様（海外からの患者様を含みます）を対象にご利用いただけます。泌尿器科宛てに事前にメールでご手配ください。 bhquro@bdms.co.th. サミティベート・シラチャは対面診療のみです。料金に関するお問い合わせは当ウェブサイトではなく、病院にお問い合わせください。.

免責事項 この記事の内容は、バンコク病院本社（Bangkok Hospital Headquarters）の認定泌尿器科医であるソラウィー・ウィーラソポン医師（Dr. Soarawee Weerasopone）が執筆および監修したものであり、教育目的のみを意図しています。これは医学的なアドバイス、診断、または個別の処方ではなく、個人的なメッセージングチャンネルやソーシャルメディアを通じてアドバイス、診断、処方が行われることはありません。ソラウィー医師は公開のソーシャルメディアアカウントを運営していません。彼の名前で個人的な相談を提供しているアカウントはすべて詐欺です。タイで緊急事態が発生した場合は、以下にお電話ください。 1669.