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Guidewires

Guidewires establish and preserve access for catheters, stents, dilators, ureteroscopes, and access sheaths. In urology, 0.035-inch wires are common and 0.038-inch systems also exist, but diameter, length, coating, tip configuration, stiffness, and device compatibility must be checked for the actual wire and the instrument passed over it. “Hydrophilic,” “stiff,” and “hybrid” describe design features and are not interchangeable clinical guarantees.[1][8]

Construction and Handling​

FeaturePractical effectBoundary
Stainless-steel or nitinol coreInfluences torque response, kink resistance, shape recovery, and shaft support[2][3][4]Core material alone does not determine clinical safety
PTFE coatingLow-friction surface on many standard wiresProduct-specific; inspect for damage and follow the IFU
Hydrophilic coatingBecomes slippery when wet and can facilitate difficult accessCan also advance beyond tactile feedback; maintain visualization and do not force against fixed resistance
Floppy, angled, straight, or shaped tipHelps negotiate different anatomyA soft tip can still enter a false passage or perforate
Stiff shaftSupports dilation, stent, sheath, or tract instrumentationExchange only after secure access; a stiff wire can straighten anatomy and transmit force

Hydrophilic wires must remain wetted as directed by the manufacturer. Keep the wire controlled at both ends, avoid scraping the coating through damaged metal, and stop when the wire path or distal position is uncertain.

Functional Categories​

Access wires​

Standard or floppy-tip wires are used for initial retrograde or antegrade access. Tip length, shape, and shaft support vary substantially. Clayman and colleagues compared physical properties of several 0.035-inch wires in bench models; those measurements are useful for understanding relative behavior, but they are not patient-level complication rates.[1]

Hydrophilic wires​

Hydrophilic wires can cross tight, tortuous, or edematous segments with less insertion resistance in some models. Two often-cited studies must be kept in context:

  • In a benchtop impacted-stone model, hydrophilic wires had higher bypass success than hybrid and standard wires; the Glidewire and HiWire required the least measured force in that apparatus.[5]
  • In an in-vitro comparison of ten hydrophilic wires, Glidewire variants required relatively high force to perforate the test model, but the Glidewire also generated the highest friction forces; the study does not support calling it universally the “lowest-friction” or “safest” wire.[6]

These results can inform product familiarity and simulation, but anatomy, wire direction, visualization, pathology, and operator technique dominate the clinical decision.

Working or stiff wires​

Stiff wires provide axial support for stents, access sheaths, tract dilators, and other devices. The Amplatz Super Stiff is one commonly used example. Bench measurements have shown greater buckling resistance than several hybrid wires, but a 2022 systematic review found no standardized definition of guidewire stiffness and sparse comparable data across products; manufacturer labels are not a common quantitative scale.[7][8]

Hybrid wires​

Hybrid wires combine a lubricious or hydrophilic distal segment with a more supportive shaft. Bench testing demonstrates measurable differences in shaft stiffness, lubricity, and tip geometry between products; “hybrid” alone does not specify those properties.[7]

Reconstructive-Urology and Urogyn Uses​

  • Retrograde pyelography and ureteral stent placement to define the ureter or a ureteral narrowing.[17]
  • Iatrogenic ureteral injury management when a wire can be passed across the injured segment under direct and/or fluoroscopic control before stenting or repair.
  • Ureteral reimplantation or Boari-flap planning using retrograde pyelography and an open-ended ureteral catheter, rather than a “preoperative RUG,” which is a urethral study.
  • Difficult urethral catheterization with objectively confirmed intravesical wire access, followed by an appropriate catheter or dilator system.
  • PCNL and antegrade nephroureteral access, where wire support must match tract dilation and sheath requirements.
  • Selective ureteral identification during complex pelvic surgery. Prophylactic catheters or stents can aid identification in selected cases but do not guarantee prevention of injury. A 2024 systematic review/meta-analysis of complex gynecologic surgery found no lower ureteric-injury risk with prophylactic catheterization/stenting.[18]

Difficult Urethral Access​

The Freid–Smith technique passed a hydrophilic wire per urethra like a filiform, confirmed intravesical location with a ureteral catheter, exchanged to a PTFE-coated wire, and then performed dilation or catheter placement. It succeeded in 19 of 20 attempts in a small 1996 series, including several after failed filiform passage.[9]

When prior attempts have caused bleeding, severe pain, or suspected false passage, flexible cystoscopy and direct wire placement are preferred over repeated blind advancement. Wire entry into the bladder should be confirmed before dilation or Council-tip catheter placement.

Selection Framework​

Choose a wire by the task and by the device that must follow it:

QuestionWhy it matters
Can the true lumen be seen or otherwise confirmed?A wire is not protective if it is in a false passage
Is the immediate goal access or support?A floppy access wire and a stiff working wire solve different problems
What wire diameter and length does the next device accept?Mismatch can prevent passage or compromise control
Is hydrophilic crossing needed?Lubricity can help, but reduced tactile feedback requires careful imaging/vision
Does the wire need to be exchanged?Use an appropriate open-ended catheter while preserving secure access
Is the anatomy injured, irradiated, reconstructed, or markedly tortuous?Lower the threshold for direct visualization, contrast confirmation, and a retained safety access strategy

Avoid declaring one named wire “gold standard,” “safest,” or mandatory from bench performance alone.

Safety Wire During Ureteroscopy​

Routine placement of a second safety wire during uncomplicated ureteroscopy is debated:

  • Ulvik and colleagues retrospectively compared 500 ureteroscopies at each of two hospitals (safety wire used in 96.2% versus 1.4%). Ureteroscope passage, stone access, stent placement and intraoperative complications did not differ. Postendoscopic stenosis was higher (3.4% versus 1.2%) and stone-free rate lower (77.1% versus 85.9%) at the routine-safety-wire hospital. The two-center comparison is vulnerable to case-mix and practice differences.[10]
  • Eandi combined ex-vivo force testing with a clinical series performed without a safety wire; Dickstein reported a selected series of uncomplicated flexible ureteroscopy without routine safety wire.[11][12]
  • A disengaging-wire access-sheath series illustrates one device-specific way to preserve access without a separate parallel wire; it does not validate every sheath or anatomy.[13]
  • Dutta and colleagues argued against mandatory routine use in uncomplicated cases while retaining it for difficult access, large stone burden, or ureteral pathology.[14]

These studies support selective practice and do not support a universal conclusion that safety wires are obsolete. When access is tenuous, anatomy is injured or reconstructed, or loss of access would materially change the operation, retaining a safety wire may be prudent.

Bench Perforation and Insertion Data​

  • Pedro and colleagues measured perforation force in isolated human and porcine ureters; human tissue required less force in that ex-vivo model. This is a tissue-model warning, not a bedside force threshold.[15]
  • Torricelli's in-vitro hydrophilic-wire comparison measured puncture force, shaft stiffness, tip bending, and friction; different wires led different metrics.[6]
  • Graversen's ex-vivo porcine model found greater access-sheath insertion force with an extraluminal safety wire, without a statistically significant difference in laceration in that model.[16]

Do not translate these apparatus-specific numbers into claims of clinical perforation probability.

Practical Safety Points​

  • Confirm the distal wire position before advancing a dilator, stent, catheter, or sheath.
  • Never advance a device against unexplained resistance solely because a wire is present.
  • Keep hydrophilic coatings wet and inspect for damage or delamination.
  • Exchange to a stiff wire only after secure access, using a compatible catheter and adequate wire length.
  • Preserve enough wire outside the patient to prevent loss of access during exchanges.
  • Treat a kinked, stripped, frayed, or contaminated wire as compromised.
  • If anatomy or wire position is uncertain, stop and re-establish visualization or imaging.

See also: Open-Ended Ureteral Catheters, Double-J Stent, Nephrostomy Tube, Balloon Dilator, S-Shaped Coaxial Dilators, and Filiforms & Followers.

References​

1. Clayman M, Uribe CA, Eichel L, et al. Comparison of guide wires in urology. Which, when and why? J Urol. 2004;171(6 Pt 1):2146–2150. doi:10.1097/01.ju.0000124486.78866.a5

2. Liguori G, Antoniolli F, Trombetta C, et al. Comparative experimental evaluation of guidewire use in urology. Urology. 2008;72(2):286–289. doi:10.1016/j.urology.2007.12.098

3. Gotman I. Characteristics of metals used in implants. J Endourol. 1997;11(6):383–389. doi:10.1089/end.1997.11.383

4. Balakrishnan N, Uvelius B, Zaszczurynski P, Lin DL, Damaser MS. Biocompatibility of nitinol and stainless steel in the bladder: an experimental study. J Urol. 2005;173(2):647–650. doi:10.1097/01.ju.0000143197.93944.14

5. Amasyali AS, Groegler J, Hajiha M, et al. What guidewire is the best for bypassing an impacted ureteral stone? J Endourol. 2020;34(5):629–636. doi:10.1089/end.2020.0058

6. Torricelli FC, De S, Sarkissian C, Monga M. Hydrophilic guidewires: evaluation and comparison of their properties and safety. Urology. 2013;82(5):1182–1186. doi:10.1016/j.urology.2013.07.024

7. Sarkissian C, Korman E, Hendlin K, Monga M. Systematic evaluation of hybrid guidewires: shaft stiffness, lubricity, and tip configuration. Urology. 2012;79(3):513–517. doi:10.1016/j.urology.2011.10.017

8. Kolvatzis M, Sierra A, Corrales M, Traxer O. Stiff guidewires in endourology: what is stiffness? J Endourol. 2022;36(11):1475–1482. doi:10.1089/end.2022.0165

9. Freid RM, Smith AD. The Glidewire technique for overcoming urethral obstruction. J Urol. 1996;156(1):164–165. PMID:8648783

10. Ulvik Ø, Rennesund K, Gjengstø P, Wentzel-Larsen T, Ulvik NM. Ureteroscopy with and without safety guide wire: should the safety wire still be mandatory? J Endourol. 2013;27(10):1197–1202. doi:10.1089/end.2013.0248

11. Eandi JA, Hu B, Low RK. Evaluation of the impact and need for use of a safety guidewire during ureteroscopy. J Endourol. 2008;22(8):1653–1658. doi:10.1089/end.2008.0071

12. Dickstein RJ, Kreshover JE, Babayan RK, Wang DS. Is a safety wire necessary during routine flexible ureteroscopy? J Endourol. 2010;24(10):1589–1592. doi:10.1089/end.2010.0145

13. Breda A, Emiliani E, Millán F, et al. The new concept of ureteral access sheath with guidewire disengagement: one wire does it all. World J Urol. 2016;34(4):603–606. doi:10.1007/s00345-015-1638-9

14. Dutta R, Vyas A, Landman J, Clayman RV. Death of the safety guidewire. J Endourol. 2016;30(9):941–944. doi:10.1089/end.2016.0314

15. Pedro RN, Hendlin K, Weiland D, et al. In vitro evaluation of ureteral perforation forces. Urology. 2007;70(3):592–594. doi:10.1016/j.urology.2007.04.050

16. Graversen JA, Valderrama OM, Korets R, et al. The effect of extralumenal safety wires on ureteral injury and insertion force of ureteral access sheaths: evaluation using an ex vivo porcine model. Urology. 2012;79(5):1011–1014. doi:10.1016/j.urology.2011.11.002

17. Linder BJ, Occhino JA. Cystoscopic ureteral stent placement: techniques and tips. Int Urogynecol J. 2019;30(1):163–165. doi:10.1007/s00192-018-3762-8

18. Gurumurthy M, McGee AE, Saraswat L. Prophylactic ureteric catheterisation during complex gynaecological surgery: a systematic review and meta-analysis. BJOG. 2024;131(10):1341–1351. doi:10.1111/1471-0528.17823