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Trans & paraurethral Injections

The Australian Centre for Female Pelvic and Vaginal Rejuvenation
The Australian Centre for Female Pelvic and Vaginal Rejuvenation

What are trans & paraurethral injections?

Trans & Paraurethral Injections are techniques for performing urethral bulking procedures for the purpose of treating stress urinary incontinence. They are frequently reserved as secondary treatment options for patients unwilling or medically unfit to undergo more invasive surgery. These material area associated with low efficacy rates compared with surgical incontinence therapies, a need for repeat treatments because of symptom recurrence and problems with the injection of some synthetic agents. 

How do trans & paraurethral injections work?

These procedures involve injecting synthetic and autologous fillers into the wall of the urethra to aid in coaptation (closure) of the mucosa, thus artificially inflating the submucosal tissues of the bladder neck and urethra and restoring the mucosal seal mechanism of continence. Glutaraldehyde cross-linked bovine collagen remains the most commonly injected biomaterial and has a cure rate of up to 53 %. Newer materials, though offer the potential of improved durability, biocompatibility and ease of administration.

Route of application


The bulking agent is injected from within the urethra into the submucosal tissues. The needle is passed through the operating channel of the cystoscope. The needle is on direct view as it is placed through the mucosa and then the mucosa observed during injection of the material.


The material is injected from the vaginal approach into the submucosa of the urethra. The needle is passed through the paraurethral epithelium and never goes through the urethral submucosal lining. Coaptation of the suburethral mucosa as the material is injected can be viewed through a cystoscope sited in the urethra. The cystoscope does not need to have an operating channel as this is not used.

Materials used for injection

A variety of materials have been historically used as urethral bulking agents. These treatments are most effective in patients with a relatively fixed urethra and evidence of intrinsic sphincter deficiency. They are much less effective in women who have poor urethral support and significant pubourethral ligament detachment on coughing.

  • Autologous fat.
  • Glutaraldehyde cross-linked bovine collagen.
  • Calcium hydroxylapatite.
  • Pyrolytic carbon-coated beads.
  • Polydimethylsiloxane.
  • Ethylene vinyl alcohol copolymer.
  • Dextranomer hyaluronic acid.
  • Polytetrafluoroethylene.
  • Polyacrylamide.

Indications for trans & paraurethral injections

As first line therapy for stress incontinence in women who;

  • experience stress incontinence after pessary placement for vaginal prolapse
  • may not be suitable candidates  for general anaesthesia and conventional surgery usually because they are:
  1. high risk surgical candidates because of a pre-existing medical condition.
  2. known to have urethral scarring and immobility related to previous pelvic irradiation or surgery.

As second or third line therapy for stress incontinence in women who;

  • have had two or more incontinence procedures that have resulted in failure with the finding of a fixed, open urethra or bladder neck.
  • experience stress incontinence after pessary placement for vaginal prolapse.

Risks associated with trans & paraurethral Injections

  • Failure to be effective.
  • Need to repeat the treatment on an ongoing basis.

Tissue reactions problems including:

  • Immunogenic reactions.
  • Marked tissue fibrosis.
  • Significant inflammatory response.
  • Poor biocompatibility.

Issues with migration, leakage, and resorption of injected material challenge therapeutic durability and can pose a health risk.

Dr Onuma’s current practice

Dr Onuma currently uses a system that uses a homogenous hydrophilic gel composed of 2.5% polyacrylamide and 97.5% water. In comparison to many other materials available it is biocompatible, has no immunogenicity, produces minimal fibrosis in surrounding tissues and induces little inflammatory response. The material is fully incorporated in the tissue and the bulking effect is directly proportional to the volume injected.

Injection technique

Homogenous Hydrophilic Gel
  • Admit for procedure.
  • Position on treatment chair or bed.
  • Choice of local anaesthesia, sedation, twighlight anaesthesia or general anaesthesia.
  • Cleanse urethra and vaginal introitus.
  • Assembly specialised operating cystourethroscope.
  • Prepare hydrophilic gel injection needles.
Hydrophilic gel kit
Hydrophilic gel kit
The device is introduced into the urethra
The device is introduced into the urethra
Passed into the bladder neck
Passed into the bladder neck
Withdrawn to the midurethra
Withdrawn to the midurethra
Injecting needle passed through into the urethral submucosa
Gel injected at 6, 3 and 9 o'clock
Gel injected at 6, 3 and 9 o'clock
Injection at 6 o'clock raises the urothelium
The bladder is emptied at the end of the procedure
The bladder is emptied at the end of the procedure

Antibiotic cover is given during the procedure.

Usual day case procedures considerations apply such as return to driving, use of heavy machinery etc.

You will receive specific advice pertinent to your own circumstances.

Followup will be arranged for you and any decision made about future treatments will be based on response and duration of response to this treatment.

Laser Vaginal Rejuvenation Institute of Adelaide
Laser Vaginal Rejuvenation Institute of Adelaide