Surgical Sphincterotomy

1. Concept

  • Therapeutic destruction of the closure mechanism of the striated, and sometimes the proximal urethral sphincter function by endoscopic incision.

2. History

  • In 1936, Watkins mentioned that increased urethral resistance in SCI males lay distally in the urethra, at the level of the diaphragm [Watkins 1936].
  • In 1957-1958, Ross et al published the first large clinical series of resection of the external urethral sphincter in the 10 SCI patients [Ross 1957; Ross 1958]
  • Its efficacy has been demonstrated for the treatment and prevention of upper tract complications due to DSD. A significant improvement in bladder emptying was reported in 70-90% of cases [Wein 1976]
  • Technical variants are:
    • Transurethral resection of several chips posteriolaterally from the external sphincter; diathermic hemostasis not effective; application of large catheter to compression [Ross 1987]
    • Laser sphincterotomy to reduce bleeding complications [Perkash 1994]. No prospective randomized study between laser versus conventional sphincterotomy.

3. Terminology

  • Also called as ‘endoscopic sphincterotomy’, ‘rhabdosphincterotomy’ or ‘external sphincterotomy’ where the distal sphincter is incised, and “total sphincterotomy” when both elements are incised.

4. Purpose of this procedure

5. Indication

  • The primary indication for this procedure is DSD in a male patient when other types of management have been unsuccessful or are not possible. [VIDEO]
  • DSD causing hydronephrosis, VUR, AD (due to poor bladder emptying), and recurrent UTI (due to poor bladder emptying) [Reynard 2003]. For more information, please refer to this and this.
    • Note the early concepts were borrowed from the study of obstructive uropathy in patients with PBH and residual urine and infection related to that problem, and ureteral dilation was though dur to compression of the urters in the intramural part of their coure due to detrusor hypertrophy.
    • The effect of sphincterotomy was thought to be improved emptying and thus a lack of residual urine.
    • Pressure data was rarely noted, and sphincterotomy was often repeated in an effort to get rid of residual urine- which amost never happened. 
    • The measureable effect od a sphincterotomy was reduction in voiding pressure and with time improved compliance and reversal of bladder morphologic changes related to DSD.

6. Procedure

  • The 12 o’clock sphincterotomy [Madersbacher 1975]
    • The striated sphincter is bulky on the anteromedial aspect of the urethra, and is incised there.
    • This approach avoids significant bleeding as the blood supply is primarily lateral and avoids postoperative erectile dysfunction by avoiding the neurovascular bundle.
  • Incision can be performed by use of a knife electrode, resection with a loop electrode, or laser ablation.
  • The incision has to be extended from the level of the veru to the bulbar urethra.
  • Incision should be deepened gradually for good visual control, minimization of significant hemorrhage and extravasation.
  • A 22 Fr urethral catheter is left in place for 1-2 days to tamponade bleeding and continuous irrigation should be intitated to prevent clot retention.
  • Inadequate surgical procedure (either too shallow or not extensive enough) can lead early failure.
  • A degree of continence may be maintained if bladder neck function is preserved.
  • Bladder neck obstruction may indicate that a bladder neck incision should be considered when an external sphincterotomy is performed [Lockhart 1986]. In high lesions it is better to incise the bladder neck, prostatic urethra, and the external sphincter as described above. The objective is to reduce outlet resistance to virtually 0. Continence is relative here since condom catheter drainage is a common part of management in these cases. In theLockhart’s paper, poor detrusor contractility is a frequent problem after sphincterotomy in quadriplegic patients. Part of the drive for the detrusor is the contracting sphincter ad when that is removed poor detrusor function evolves: hence our practice of total sphincterotomy in the high quad patient.

7. Clinical Outcomes

Authors (Year)




Lockhart JL, Vorstman B, Weinstein D, Politano VA. (J Urol. 1986)

Among 60 SCI patients who underwent external urethral sphincterotomy


45 experienced success and 15 failed.

Urodynamic cause of failure:
66.0% detrusor areflexia
13.2% DSD
6.6% detrusor hyperreflexia with unsustained bladder contractions
13.2% detrusor hyperreflexia and bladder neck obstruction

Among these failures poor detrusor contractility predominated.

DSD may indicate an inadequate surgical relief of obstruction.

Bladder neck obstruction may indicate that a bladder neck incision should be considered when an external sphincterotomy is performed.

Yang CC, Mayo ME. (Neurourol Urodyn. 1995)

Retrospective review of 37 male SCI patients who underwent sphincterotomy

Urodynamic study


Eighteen' operations were failures and 19 operations were successful.

Reoperation rate 32%.

Urodynamic cause of failure:
recurrent DSD (6),
detrusor hypocontractility (6),
bladder neck contracture (3),
stricture (1)
incomplete sphincterotomy (1)
unknown etiology (1).

A high failure rate over time even in appropriately selected patients

There was no predictor of failure using present selection criteria.

Kim YH, Kattan MW, Boone TB. (J Urol. 1998)

55 SCI patients

Mean followup 11 year

Review of the urodynamic studies


Failure rate 65% (detrusor leak point pressure (DLPP) > 40 cmH2O)

Patients with DLPP > 40cmH2O had a significantly higher incidence of upper tract damage and persisting external DSD.

DLPP > 40cmH2O is a valid indicator of failure of sphincterotomy.


8. Advantages

  • Prevent upper tract complications due to DSD
  • significant improvement in bladder emptying

9. Disadvantages

  • Operative complications
      • Significant hemorrhage (13-23%) [Kiviat 1975; Chancellor 1994]
      • Erectile dysfunction (3-32%) [Carrion 1979; Schoenfeld 1974]  
  • Most patients become reliant upon condom-catheter drainage
      • Not suitable for women 
      • Not suitable to obese patients whose penis tend to be buried and an  external appliance can not be applied: Some patients may require a penile prosthesis.
      • Not suitable to those who has potential skin allergy to the external appliance 
  • Failure
    • Failure to solve the problems
      • Persistent high intravesical pressure, VUR, hydronephrosis, recurrent UTI or AD
      • Failure to fully eliminate residual urine rarely happens even with a good sphincterotomy
      • Detrusor leak point pressure > 40cmH2O is a valid indicator of failure [Kim 1998]. For more information, please refer to this (link to the BC-10. Risk Factors to the Upper Tract Damage in SCI)
    • Causes of late failure [Lockhart 1989]
        • fibrosis somewhere along the extent of the sphincterotomy
        • a change in detrusor function
        • the development of prostatic obstruction
        • a change in neurologic status such that smooth sphincter dyssynergia develops
    • Need to repeat the procedure in up to 25% of patients [Schellhammer 1973]

10. Current Significance

  • Sphincterotomy has been an effective treatment modality for the treatment for the patients with DSD and patients with reflex bladder activity after World War II.
  • However, nowadays, as effective and alternative treatment options for the DSD stents, botulinum toxin and the hyperreflexic bladder (medication or operation) have become a more favorable bladder management, sphincterotomy seems to be an alternative only in quadriplegic patients who are not able to perform CIC.



Effective at reducing detrusor leak point pressure, may have to be modified to include the entire sphincter


Risks are bleeding and autonomic dysreflexia

Ease of application

Requires considerable skill and practice

Patient Comfort

Condom catheter usage may be difficult, or impossible


Moderate over time but appliances and follow up are required

11. Other comments

  • There is some disagreement about the rate of postoperative development of erectile dysfunction. Estimates using the 3 and the 9 o’clock technique vary from 5% to 30%, but it is clear that this complication is far less common (approximately 5%) with incision in the anteromedial position.
  • Total incontinence or severe stress urinary incontinence is unusual after sphincterotomy unless the bladder neck and proximal urethra has been compromised by prior surgical therapy or by the neurologic lesion itself.


Key Points of This Section

  • Sphincterotomy is effective in patients with upper motor neuron lesions.
  • It is usually done in quads but that indication requires a total sphincterotomy
  • The effect of sphincterotomy is on voiding pressure not residual urine.



  • Carrion HM, Brown BT, Politano VA. External sphincterotomy at the 12 o'clock position. J Urol. 1979 Apr;121(4):462-3.
  • Chancellor MB, Rivas DA, Abdill CK, Karasick S, Ehrlich SM, Staas WE. Prospective comparison of external sphincter balloon dilatation and prosthesis placement with external sphincterotomy in spinal cord injured men. Arch Phys Med Rehabil. 1994 Mar;75(3):297-305.
  • Kim YH, Kattan MW, Boone TB: Bladder leak point pressure: The measure for sphincterotomy success in spinal cord injured patients with external detrusor sphincter dyssynergia. J Urol 1998;159:493–497.
  • Kiviat MD. Transurethral sphincterotomy: relationship of site of incision to postoperative potency and delayed hemorrhage. J Urol. 1975 Sep;114(3):399-401.
  • Lockhart JL, Pow-Sang JM: Indications and problems with external urethral sphincterotomy. Probl Urol 1989;3:44–53.
  • Lockhart JL, Vorstman B, Weinstein D, Politano VA. Sphincterotomy failure in neurogenic bladder disease. J Urol. 1986 Jan;135(1):86-9.
  • Madersbacher H, Scott FB: Twelve o’clock sphincterotomy. Urol Int 1975;30:75–81.
  • Perkash I. Laser sphincterotomy and ablation of the prostate using a sapphire chisel contact tip firing neodymium:YAG laser. J Urol. 1994 Dec;152(6 Pt 1):2020-4.
  • Reynard JM, Vass J, Sullivan ME, Mamas M. Sphincterotomy and the treatment of detrusor-sphincter dyssynergia: current status, future prospects. Spinal Cord. 2003 Jan;41(1):1-11.
  • Ross JC, Damanski M, Gibbon N. Resection of the external urethral sphincter in the paraplegic; preliminary report. Trans Am Assoc Genitourinary Surg. 1957;49:193-8.
  • Ross JC, Damanski M, Gibbon N. Resection of the external urethral sphincter in the paraplegic; preliminary report. J Urol. 1958 Apr;79(4):742-6.
  • Ross JC, Gibbon NO, Damanski M. Division of the external urethral sphincter in the treatment of the paraplegic bladder: a preliminary report on a new procedure. Paraplegia. 1987 Jun;25(3):185-95.
  • Schellhammer PF, Hackler RH, Bunts RC. External sphincterotomy: an evaluation of 150 patients with neurogenic bladder. J Urol 1973; 110: 199-202.
  • Schoenfeld L, Carrion HM, Politano VA. Erectile impotence: complication of external sphincterotomy. Urology. 1974 Dec;4(6):681-5.  
  • Watkins KH. The bladder function in spinal injury. Br J Surg. 1936:23:734-759.
  • Wein AJ, Raezer DM, Benson GS: Management of neurogenic bladder dysfunction in the adult. Urology 1976;8:432–438.
  • Yang CC, Mayo ME. External urethral sphincterotomy: long-term follow-up. Neurourol Urodyn. 1995;14(1):25-31.

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