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Sachse Urethrotome

Endoscope-mounted cold-knife urethrotome — the standard instrument for direct-vision internal urethrotomy (DVIU), the dominant endoscopic technique for male urethral stricture worldwide. Introduced by Hans Sachse in 1973, 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 standard size used in the landmark Heyns / Steenkamp trial and most clinical series).[1]
  • Rod-lens telescope (typically 0° or 5°) integrated into the sheath; standard light cable.
  • Retractable cold-knife blade deployed and withdrawn by a thumb / lever mechanism on the handle; standard cut position 12 o'clock (dorsal midline) under direct vision.[2]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 + glass optics; autoclavable.

Principle of Operation​

Unlike dilation (axial shearing / 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 — Otis's original principle, now executed under direct vision.[3]

Reconstructive-Urology Uses​

The Sachse is the workhorse 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 — the optimal indication; AUA 2023 first-line option alongside dilation, with success rates highest in bulbar < 1 cm disease.[3][7]
  • Vesicourethral anastomotic stenosis (VUAS) and bladder-neck contracture (BNC) — DVIU with the Sachse at 5 and 7 o'clock has been described to avoid the dorsal neurovascular complex; mitomycin-C augmentation is increasingly used for the recurrent posterior contracture.[6]
  • Short recurrence after urethroplasty — explicitly endorsed by the 2026 EAU guideline as a reasonable salvage option.[8]
  • Office / local-anesthesia DVIU — feasible for select cases, a significant advantage over the GA-/regional-anesthesia-typical Otis technique.[4]

Technique — Standard Anterior DVIU​

  1. Anesthesia — GA / regional / 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. 5 / 7 o'clock positions for posterior strictures / VUAS to spare the dorsal NVB.[2][6]
  5. Multiple incisions — Giannakopoulos 1997 compared standard single-12-o'clock cut to the Guillemin double 11 / 1 o'clock + transurethral scar resection technique: at 5 years 70% vs 25% good outcomes (p < 0.05).[2]
  6. 18 Fr silicone Foley at the end of the case; 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 predominance1973 – presentLate 1800s – 1970s

Outcomes​

SeriesnTechniqueFollow-upSuccess
Kirchheim 1978[4]36Sachse DVIU≥ 6 mo80% (distal) / 100% (bladder neck)
Smith 1981[9]39Sachse DVIU25 mo mean82% symptom-free / 13% improved
Renders 1979[10]44Sachse DVIU14 mo mean77–82%
Sandozi / Ghazali 1988[5]143Modified Sachse> 6 yr85% 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

Key prognostic findings:[3][7][11]

  • Best outcome — primary, short (< 2 cm), isolated bulbar stricture, minimal spongiofibrosis.
  • Length — each additional cm adds a relative risk of recurrence ~ 1.22.
  • Repeat DVIU — failure rates > 80% after a second endoscopic procedure; prior DVIU is a strong recurrence predictor (HR 1.78, 95% CI 1.05–3.03).
  • Median time to recurrence ~ 6 months (IQR 2–12).
  • ≥ 50% of men develop a recurrence over their lifetime.

Adjunctive Therapies​

  • Self-catheterization > 4 months after DVIU significantly reduces recurrence vs < 4 months in the AUA-cited literature.[7]
  • Intralesional mitomycin-C (0.4 mg/mL in 0.2–0.4 mL aliquots at 12, 3, 9 o'clock) — Farrell 2017 reported 75% success at 25.8 mo in recurrent strictures that had failed prior endoscopy or urethroplasty.[12]
  • Corticosteroid injection — limited evidence in short strictures.[3]
  • Drug-coated balloon after DVIU — AUA 2023 endorses for recurrent bulbar < 3 cm stricture; see Drug-Coated Balloon Therapy.[7]

Safety Profile​

  • Hemorrhage — common, usually self-limited; catheter tamponade.[3]
  • UTI / bacteremia / sepsis — prophylactic antibiotics; defer DVIU in active UTI.[3]
  • False passage — lower than with blind techniques but still possible in dense / obliterative strictures.
  • Erectile dysfunction — ~ 2–10%; mechanisms include cavernous-nerve injury, corpus-cavernosum–spongiosum fistula, and fibrosis from irrigant / urinary extravasation.[13]
  • Urinary extravasation — full-thickness cut through corpus spongiosum can allow irrigant / urine to extravasate into periurethral tissues and worsen fibrosis.[3]
  • Stricture recurrence — 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 men treated with urethrotomy were 3.39 × more likely (95% CI 1.62–7.07) to require further surgery than those treated with primary urethroplasty — 64% of the urethrotomy group required continued self-dilation or further surgery at 2 years vs 24% of the urethroplasty group.[1]

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. Comparative data have not demonstrated clear superiority of laser over cold-knife urethrotomy; the cold-knife Sachse remains the most widely used and most extensively studied DVIU platform.

Historical Significance​

The Sachse urethrotome transformed stricture management by introducing 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