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Sachse Urethrotome

The Sachse urethrotome is an endoscope-mounted cold-knife urethrotome used for direct-vision internal urethrotomy (DVIU), the dominant endoscopic technique for male urethral stricture worldwide. Introduced by Hans Sachse (first reported in 1974), it replaced the blind Otis urethrotome with a visually guided cold-knife incision under continuous-irrigation endoscopy and remains the standard of care wherever endoscopic equipment is available.[1]

Design​

  • 21 Fr outer caliber, the usual adult size.
  • Rod-lens telescope (typically 0° or 30°) integrated into the sheath; standard light cable.
  • Retractable cold-knife blade deployed and withdrawn by a thumb or lever mechanism on the handle; the standard cut position is 12 o'clock (dorsal midline) under direct vision.[2]
  • Continuous irrigation channel distends the urethra and maintains a clear visual field.
  • Working channel for guidewire or small ureteral catheter to pre-define the true lumen before incision.
  • Stainless steel and glass optics; autoclavable.

Principle of Operation​

Unlike dilation (axial shearing or stretch), the Sachse delivers a controlled longitudinal cold-knife incision through the full thickness of scar into healthy periurethral tissue. The wound edges separate and re-epithelialize across a wider lumen, healing at the new caliber. This is Otis's original principle, now executed under direct vision.[3]

Reconstructive-Urology Uses​

The Sachse is the standard instrument for the DVIU procedure across the male anterior and posterior urethra. For the full procedural framework, outcomes, adjuncts, and decision logic, see DVIU and Urethral Dilation.

  • Primary, isolated, short (< 2 cm) bulbar stricture. This is the optimal indication; AUA 2023 lists it as a first-line option alongside dilation, with success rates highest in bulbar disease < 1 cm.[3][7]
  • Vesicourethral anastomotic stenosis (VUAS) and bladder-neck contracture (BNC). DVIU at 5 and 7 o'clock, with or without mitomycin-C injection, has been described in a three-patient technique report (Klein 2024) to avoid the dorsal midline; long-term outcome data are limited.[6]
  • Recurrence after urethroplasty. The 2026 EAU guideline notes that DVIU has been used as salvage: patency after a single DVIU was 35% (13 of 37) for recurrences after EPA or graft urethroplasty in one series, and 51% for short veil-like strictures after buccal graft urethroplasty in another.[8]
  • Office or local-anesthesia DVIU is feasible for select cases, a significant advantage over the general- or regional-anesthesia-typical Otis technique.[4]

Technique — Standard Anterior DVIU​

  1. Anesthesia. General, regional, or local with intraurethral 2% lidocaine in select cases.[4]
  2. Dorsal lithotomy; initial cystourethroscopy to define stricture location, length, caliber.
  3. Guidewire across the stricture (or via small ureteral catheter passed through the working channel) to confirm the true lumen. The Sandozi / Ghazali pediatric-cystoscope modification extended this to even the most difficult strictures.[5]
  4. Cold-knife incision under direct vision at 12 o'clock (anterior urethra), through scar into pink, bleeding periurethral tissue. Use 5 and 7 o'clock positions for posterior strictures and VUAS to spare the dorsal NVB.[2][6]
  5. Multiple incisions. Giannakopoulos 1997 compared a standard single 12-o'clock cut with the Guillemin double 11 and 1 o'clock incision plus transurethral scar resection: in 80 patients with 1 to 2 cm bulbar strictures, good results at 5 years were 70% with the Guillemin technique versus 25% with the single cut (p < 0.05).[2]
  6. 18 Fr silicone Foley at the end of the case, with catheter 24–72 h. AUA 2023 finds no benefit to durations > 72 h.[1][7]

Sachse (DVIU) vs Otis (Blind)​

FeatureSachse (DVIU)Otis (blind)
VisualizationDirect endoscopicNone
MechanismCold-knife incision under visionExpand → blade cuts on withdrawal
Incision controlSurgeon selects site / depthCuts whatever is at 12 o'clock
Stricture traversalProgressive proximal-to-distal under visionMust pass through / past stricture first
AnesthesiaGA / regional / localGA / regional typical
False-passage riskLower (visual)Higher (blind)
Era of predominance1974 – presentLate 1800s – 1970s

Outcomes​

SeriesnTechniqueFollow-upSuccess
Kirchheim 1978[4]36Sachse DVIU≥ 6 moGood results in 16 of 20 (80%) distal strictures and 16 of 16 bladder-neck contractures
Smith 1981[9]39Sachse DVIU25 mo mean82% symptom-free / 13% improved
Renders 1979[10]44Sachse DVIU14 mo mean77–82%
Sandozi / Ghazali 1988[5]143 (210 procedures)Modified Sachse6-yr experience (52 followed > 6 yr)85% resolved
Giannakopoulos 1997[2]40 (Sachse arm)Sachse 12 o'clock5 yr25% (declined from 95% at 6 mo)
Kluth 2017[11]128DVIU16 mo median51.6% overall

Prognostic findings:[3][7][11]

  • Best outcome. Primary, short (< 2 cm), isolated bulbar stricture, minimal spongiofibrosis.
  • Length. Each additional cm of stricture length adds a relative risk of approximately 1.22 (Verla review).
  • Repeat DVIU. The AUA guideline cites failure rates > 80% for strictures already treated with dilation or DVIU; in the Kluth series, repeat DVIU was the only independent predictor of recurrence (HR 1.78, 95% CI 1.05–3.03).
  • Median time to recurrence is approximately 6 months (IQR 2–12).
  • Overall success was 51.6% at a median follow-up of 16 months in the Kluth series, so about half recurred.

Adjunctive Therapies​

  • Self-catheterization after DVIU lowered recurrence in pooled studies (RR 0.51, 95% CI 0.32–0.81). Data suggest more than 4 months is better than less than 3 months. The AUA guideline says clinicians may recommend it for patients who are not urethroplasty candidates (Conditional Recommendation).[7]
  • Intralesional mitomycin-C. In the Farrell protocol, cold-knife incisions at 12, 3 and 9 o'clock were followed by injection of 10 mL of 0.4 mg/mL mitomycin-C in 0.2–0.4 mL aliquots, then one month of daily self-catheterization. Farrell 2017 (retrospective, n = 44) reported that 75% needed no further surgery at median 25.8 months in recurrent bulbar and bulbomembranous strictures that had failed prior endoscopy or urethroplasty.[12]
  • Corticosteroid injection. Evidence is limited in short strictures.[3]
  • Drug-coated balloon after DVIU. AUA 2023 states surgeons may offer it (Conditional Recommendation, Grade B) for recurrent bulbar stricture < 3 cm, and the 2026 EAU guideline gives a strong recommendation after at least two prior endoscopic treatments in patients not fit for or unwilling to have urethroplasty; see Drug-Coated Balloon Therapy.[7]

Safety Profile​

  • Hemorrhage is common and usually self-limited; catheter tamponade.[3]
  • UTI, bacteremia, sepsis. Give prophylactic antibiotics; defer DVIU in active UTI.[3]
  • False passage is lower than with blind techniques but still possible in dense or obliterative strictures.
  • Erectile dysfunction was reported in 5.3% in a systematic review of cold-knife DVIU and in 10.6% (11 of 104) in one series. The risk appears higher in penile urethral strictures, and the EAU discourages DVIU there.[8] Proposed mechanisms include cavernous-nerve injury, corpus-cavernosum–spongiosum fistula, and fibrosis from irrigant or urinary extravasation.[13]
  • Urinary extravasation. A full-thickness cut through corpus spongiosum can allow irrigant or urine to extravasate into periurethral tissues and worsen fibrosis.[3]
  • Stricture recurrence is the dominant long-term outcome event (≥ 50% over a lifetime).[1]

When to Abandon DVIU and Proceed to Urethroplasty​

The AUA 2023 guideline is explicit: surgeons should offer urethroplasty instead of repeated endoscopic management for recurrent anterior urethral strictures after failed dilation or DVIU (Moderate Recommendation, Grade C).[7] For posterior strictures after pelvic fracture, the Cochrane review found that in the first six months men treated with urethrotomy were more likely to require further surgery than those treated with primary urethroplasty (RR 3.39, 95% CI 1.62–7.07; one trial, 50 men); 64% (16 of 25) of the urethrotomy group required continued self-dilation or further surgery at 2 years versus 24% (6 of 25) of the urethroplasty group.[1] The 2026 EAU guideline gives a strong recommendation against more than two DVIU or dilations when urethroplasty is a viable option.[8]

Sachse vs Laser Urethrotomy​

Modern alternatives, holmium:YAG and thulium-laser urethrotomy, use a standard cystoscope with a laser fiber through the working channel and avoid the dedicated 21 Fr Sachse instrument. The AUA guideline states that cold-knife and laser incision appear to have similar success rates and may be used interchangeably; the cold-knife Sachse remains the most widely used and most extensively studied DVIU platform.

Historical Significance​

The Sachse urethrotome introduced visually guided incision, allowing the surgeon to see exactly where and how deeply the cut goes. The instrument's integration of optics, illumination, irrigation, and a cold knife into a single 21 Fr device set the template for every modern urethrotomy platform that followed and established DVIU as the dominant endoscopic stricture treatment for > 50 years.[1][4]

See also: Otis Urethrotome, Balloon Dilator, Van Buren Sound, Filiforms & Followers, DVIU and Urethral Dilation, Drug-Coated Balloon Therapy.

References​

1. Wong SS, Aboumarzouk OM, Narahari R, O'Riordan A, Pickard R. "Simple urethral dilatation, endoscopic urethrotomy, and urethroplasty for urethral stricture disease in adult men." Cochrane Database Syst Rev. 2012;12:CD006934. doi:10.1002/14651858.CD006934.pub3

2. Giannakopoulos X, Grammeniatis E, Gartzios A, Tsoumanis P, Kammenos A. "Sachse urethrotomy versus endoscopic urethrotomy plus transurethral resection of the fibrous callus (Guillemin's technique) in the treatment of urethral stricture." Urology. 1997;49(2):243–7. doi:10.1016/S0090-4295(96)00450-5

3. Verla W, Oosterlinck W, Spinoit AF, Waterloos M. "A comprehensive review emphasizing anatomy, etiology, diagnosis, and treatment of male urethral stricture disease." Biomed Res Int. 2019;2019:9046430. doi:10.1155/2019/9046430

4. Kirchheim D, Tremann JA, Ansell JS. "Transurethral urethrotomy under vision." J Urol. 1978;119(4):496–9. doi:10.1016/s0022-5347(17)57528-x

5. Sandozi S, Ghazali S. "Sachse optical urethrotomy, a modified technique: 6 years of experience." J Urol. 1988;140(5):968–9. doi:10.1016/s0022-5347(17)41900-8

6. Klein R, Vasan R, Guercio C, Rusilko P. "Minimally invasive management of posterior urethral stricture/stenosis with DVIU and mitomycin C injection." Urology. 2024;183:e317–e319. doi:10.1016/j.urology.2023.10.006

7. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. "Urethral stricture disease guideline amendment (2023)." J Urol. 2023;210(1):64–71. doi:10.1097/JU.0000000000003482

8. Campos-Juanatey F, Barratt R, Chan G, et al. "European Association of Urology guidelines on urethral strictures: summary of the 2026 guidelines. Update in recommendations for endoluminal management of male anterior urethral strictures." Eur Urol. 2026. doi:10.1016/j.eururo.2026.04.021

9. Smith PJ, Dunn M, Roberts JB. "Surgical management of urethral stricture in the male." Urology. 1981;18(6):582–7. doi:10.1016/0090-4295(81)90461-1

10. Renders G, De Nobel J, Debruyne F, Delaere K, Moonen W. "Cold knife optical urethrotomy." Urology. 1979;14(5):475–7. doi:10.1016/0090-4295(79)90178-x

11. Kluth LA, Ernst L, Vetterlein MW, et al. "Direct vision internal urethrotomy for short anterior urethral strictures and beyond: success rates, predictors of treatment failure, and recurrence management." Urology. 2017;106:210–5. doi:10.1016/j.urology.2017.04.037

12. Farrell MR, Lawrenz CW, Levine LA. "Internal urethrotomy with intralesional mitomycin C: an effective option for endoscopic management of recurrent bulbar and bulbomembranous urethral strictures." Urology. 2017;110:223–7. doi:10.1016/j.urology.2017.07.017

13. Kocjancic E, Chung E, Garzon JA, et al. "International Continence Society (ICS) report on the terminology for sexual health in men with lower urinary tract (LUT) and pelvic floor (PF) dysfunction." Neurourol Urodyn. 2022;41(1):140–65. doi:10.1002/nau.24846