Needles
The needle is half of the suture decision and is at least as important. A taper vs cutting choice on a 5-0 BMG fixation stitch makes the difference between a stable graft and graft-edge dehiscence; a blunt vs sharp fascial needle changes the surgeon's percutaneous injury risk by more than 50%. This article catalogs needle types, selection by urologic tissue, and the one piece of evidence-based needle-safety data that every urologic resident should know.
See also: Sutures, Incisions & Closure, Bowel Anastomosis.
Needle Anatomy
Every surgical needle has three components:[1]
- Point (tip) — determines tissue penetration characteristics.
- Body — determines strength and curvature.
- Swage — where the suture is attached (modern swaged-on design is a 1:1 diameter match with the suture, minimizing tissue trauma).
The materials and manufacturing matter: ASTM 455000 stainless steel (high-nickel maraging stainless) gives the highest tensile and yield strength and supports the longest, narrowest cutting geometries — the sharpest clinical needles.[2][3] Silicon surface coatings reduce tissue drag. Electrohoned or hand-honed tips are sharper than machine-ground tips.[2]
Needle Point Types
The point determines how the needle interacts with tissue on entry:[1][9]
| Point type | Cross-section | Action | Urologic use |
|---|---|---|---|
| Conventional cutting | Triangular, cutting edge on inner curve | Cuts tissue | Tough skin; largely displaced by reverse cutting |
| Reverse cutting | Triangular, cutting edge on outer curve | Cuts tissue; reduces cutout risk | Skin closure (standard); penile skin; fascia superficial layer |
| Taper (round body) | Round, tapers to a sharp point | Dilates tissue without cutting | Bowel, urinary tract, vessels, fascia — the urologic default |
| Blunt taper (blunt point) | Round, blunt tip | Dilates only, does not cut | Fascial closure — prevents visceral injury and reduces needlestick |
| Taper-cut | Round body + cutting tip | Punctures, then dilates | Vascular anastomosis; tough scar tissue |
Tissue-tearing evidence. In a 2025 comparative study, taper needles produced significantly lower tear-through force (4.07 N) than cutting needles (3.26 N) — taper is gentler on tissue under load.[10] Larger-diameter needles also tear less.
Needle Curvature
| Curvature | Use |
|---|---|
| 3/8 circle | Most common; workhorse for most tissues |
| 1/2 circle | Deep cavities, pelvis, confined spaces — the pelvic-surgery default |
| 5/8 circle | Deep narrow spaces, microsurgery, ophthalmic |
| Straight | Accessible superficial tissue; rarely used in urology |
| Compound curve | Specialized (transseptal cardiac, some microsurgical) |
For pelvic urology (vesicourethral anastomosis, reimplant, fistula repair), 1/2 circle is the dominant choice — it rotates cleanly in narrow pelvic corridors. For perineal urethroplasty, 1/2 or 3/8 depending on exposure.
Needle Codes — the Ethicon Naming Convention
The two-letter prefix denotes needle family; the number denotes length:
| Code | Point | Typical curvature | Urologic association |
|---|---|---|---|
| CT (Circle Taper) | Taper | 1/2 circle | Bowel (CT-1, CT-2, CT-3); augment, pyeloplasty |
| SH (Small Half-circle) | Taper | 1/2 circle | Urethra, ureter, small-diameter pelvic work |
| RB (Round Body) | Taper | 1/2 circle | Vessels, fine vascular |
| UR (Urology) | Taper | 5/8 circle | Deep pelvis — dorsal vein complex, bladder neck reconstruction |
| MH (Medium Half-circle) | Taper | 1/2 circle | Fascia, peritoneum |
| CTX | Blunt taper | 1/2 circle | Mass closure fascia (blunt) |
| PS (Plastic Surgery) | Reverse cutting | 3/8 circle | Skin; small precise cutting |
| FS (For Skin) | Reverse cutting | 3/8 circle | Skin closure |
| CP (Cutting Point) | Reverse cutting | 3/8 or 1/2 | Tougher skin/fascia |
| TP (Taper Point) | Taper | 1/2 circle | Bowel, fascia variants |
A UR-6 on 3-0 Monocryl (a common vesicourethral anastomosis stitch in open RP) is a very different tool from a CT-1 on 2-0 Vicryl (bowel anastomosis) — the UR geometry exists specifically because the dorsal vein and bladder-neck work at the prostate apex benefits from the deeper 5/8-circle rotation.
Selection by Urologic Tissue
| Tissue | Point | Example needle |
|---|---|---|
| Skin | Reverse cutting | PS-2, FS, X-1 |
| Urethra (mucosa-to-spongiosum) | Taper | SH, RB-1 |
| Urethra (graft fixation, bulbar BMG) | Taper | RB-1 on 5-0 or 6-0 PDS |
| Ureter | Taper | SH, TF |
| Bladder mucosa / detrusor | Taper | CT-1, CT-2, SH |
| Bowel (for urinary diversion) | Taper | CT-1, CT-2 |
| Fascia (mass closure) | Blunt taper | CTX blunt, SH blunt |
| Vascular (renal vein, IVC, iliac) | Taper or taper-cut | RB-1, CV needles |
| Deep pelvic apex / dorsal vein complex | Taper | UR-6 |
| Tendon / sling suspensory arms | Taper | CT-1 on Prolene |
Size — Gauge vs USP
Two parallel systems:
- Hollow/biopsy needles use Stubs Iron Wire Gauge — higher number = smaller diameter. 18 G > 22 G > 25 G.[5][6]
- Surgical suture needles are sized by length (in mm) and codified under the suture manufacturer's naming convention rather than "gauge."
Gauge is relevant to urologists primarily in biopsy, access, and percutaneous drainage, not in suture selection.
Blunt vs Sharp Suture Needles — the Safety Evidence
Percutaneous needlestick injury is a defining occupational hazard of surgery. The Cochrane review evidence on blunt-tip suture needles is unambiguous:[4]
- Glove perforation reduced by 54% (RR 0.46, 95% CI 0.38–0.54).
- Needlestick injuries reduced by 69% (RR 0.31, 95% CI 0.14–0.68).
- Prevents one glove perforation in every 6 operations.
- Applicable to abdominal fascial closure, cesarean section, vaginal repair, hip replacement, and subcuticular skin closure.
Surgeon acceptance. Blunt needles are rated "more difficult but still acceptable" — they require higher penetration force, move more slowly, and produce a tactile "pop" through fascia.[4]
Implementation gap. Despite the evidence existing for decades and American College of Surgeons / OSHA / NIOSH recommendations to use blunt needles for fascial closure, adoption is poor. In surveys, only 12% of US obstetrician-gynecologists reported currently using blunt needles, and only 49% of French operating theaters stocked them.[4][11]
Practical recommendation for urologic fascial closure (especially midline cystectomy / open nephrectomy / open RP closure): blunt taper needle is the standard.
Safe Needle Handling
Grip
- Palmar grip (all fingers around the holder, rings not used) is more accurate than the traditional ring grip for fine stitching.[12]
- Load the needle at ~90° to the holder axis; grasp at the two-thirds mark from the tip.
- Follow the curve during passage — do not pry or torque the body of the needle (it will bend or break).
Needle Transfer
- Protected transfer technique: lock the needle tip against the shaft of the needle holder before handing off.
- Before returning to the tray or handing off, pivot the needle 90° toward the instrument joint.
- Never touch the needle point to the needle driver's jaws (dulls the tip).
Microskills That Matter
Assessed in the 2022 JAMA Network Open curriculum study:[13]
- Loading the needle at the correct angle.
- Following the curve through tissue.
- Atraumatic release from tissue.
- Pitch-and-catch — forceps-assisted transfer of the needle back to the needle driver.
- Push-push-pull — reloading the needle while still in tissue, avoiding forceps so the non-dominant hand stays on retraction.
Specialty Needles
Spinal and Epidural
Relevant to every robotic prostatectomy and cystectomy for regional analgesia.
| Needle | Tip | PDPH risk |
|---|---|---|
| Quincke | Cutting, beveled | Higher |
| Greene | Cutting | Higher |
| Whitacre | Pencil-point (atraumatic) | Lower |
| Sprotte | Pencil-point (atraumatic) | Lower |
| Atraucan | Atraumatic | Lower |
Network meta-analysis: the 26-gauge atraumatic needle has the lowest combined probability of post-dural-puncture headache and procedural failure.[9]
Biopsy Needles (Percutaneous Urologic)
- Fine needle aspiration: 21–25 G — cytology only.
- Core needle biopsy: 18–20 G automatic firing with variable throw length — histologic architecture, sufficient for molecular work.[7][8]
- Overall complication rate of percutaneous needle puncture across a 66,397-puncture series: 0.51%; severe 0.057%; fatal 0.0075%. Cutting biopsy needles account for most severe events.[10]
Needle–Tissue Interaction Physics
Three phases during penetration:[16]
- Deformation — tissue stretches before puncture.
- Insertion — needle advances through tissue.
- Extraction — needle withdrawn, tissue relaxes.
Variables that increase insertion force:
- Larger diameter increases force.
- Blunt > diamond > conical > beveled tip shape (in descending insertion force).
- Smaller bevel angle reduces force.
- Higher insertion velocity generally reduces perceived force (but increases unintended depth).
- Tissue-specific: skin > liver capsule > muscle > fat > vessel wall.
Understanding these variables is why experienced reconstructionists accept the slightly higher penetration force of a blunt fascial needle (safer) and pick a sharper taper for urethral mucosa (less tear, less trauma).
References
1. Byrne M, Aly A. "The Surgical Needle." Aesthet Surg J. 2019;39(Suppl_2):S73–S77. doi:10.1093/asj/sjz035
2. Thacker JG, Rodeheaver GT, Towler MA, Edlich RF. "Surgical Needle Sharpness." Am J Surg. 1989;157(3):334–9. doi:10.1016/0002-9610(89)90565-5
3. Edlich RF, Thacker JG, McGregor W, Rodeheaver GT. "Past, Present, and Future for Surgical Needles and Needle Holders." Am J Surg. 1993;166(5):522–32. doi:10.1016/s0002-9610(05)81147-x
4. Parantainen A, Verbeek JH, Lavoie MC, Pahwa M. "Blunt Versus Sharp Suture Needles for Preventing Percutaneous Exposure Incidents in Surgical Staff." Cochrane Database Syst Rev. 2011;(11):CD009170. doi:10.1002/14651858.CD009170.pub2
5. Arevalo-Rodriguez I, Muñoz L, Godoy-Casasbuenas N, et al. "Needle Gauge and Tip Designs for Preventing Post-Dural Puncture Headache (PDPH)." Cochrane Database Syst Rev. 2017;4:CD010807. doi:10.1002/14651858.CD010807.pub2
6. Beirne PV, Hennessy S, Cadogan SL, et al. "Needle Size for Vaccination Procedures in Children and Adolescents." Cochrane Database Syst Rev. 2018;8:CD010720. doi:10.1002/14651858.CD010720.pub3
7. Wildman-Tobriner B, Ho LM, Bowman AW. "Needle Types Used in Abdominal Cross-Sectional Interventional Radiology: A Survey of the Society of Abdominal Radiology Emerging Technology Commission." Abdom Radiol. 2022;47(8):2623–2631. doi:10.1007/s00261-021-03145-1
8. Roy-Chowdhuri S, Dacic S, Ghofrani M, et al. "Collection and Handling of Thoracic Small Biopsy and Cytology Specimens for Ancillary Studies: Guideline From the College of American Pathologists." Arch Pathol Lab Med. 2020. doi:10.5858/arpa.2020-0119-CP
9. Maranhao B, Liu M, Palanisamy A, Monks DT, Singh PM. "The Association Between Post-Dural Puncture Headache and Needle Type During Spinal Anaesthesia: A Systematic Review and Network Meta-Analysis." Anaesthesia. 2021;76(8):1098–1110. doi:10.1111/anae.15320
10. Potter CT, Maloney ME, Riopelle AM, Fudem GM, Schanbacher CF. "Impact of Needle Design and Suture Gauge on Tissue Tearing During Skin Suturing: A Comparative Analysis." Dermatol Surg. 2025;51(2):148–151. doi:10.1097/DSS.0000000000004389
11. Catanzarite V, Byrd K, McNamara M, Bombard A. "Preventing Needlestick Injuries in Obstetrics and Gynecology." Obstet Gynecol. 2007;110(6):1399–403. doi:10.1097/01.AOG.0000287617.12113.3e
12. Seki S. "Suturing Techniques of Surgeons Utilizing Two Different Needle-Holder Grips." Am J Surg. 1988;155(2):250–2. doi:10.1016/s0002-9610(88)80707-4
13. Greenberg AL, Karimzada MM, Brian R, et al. "Assessment of Surgeon Performance of Advanced Open Surgical Skills Using a Microskills-Based Novel Curriculum." JAMA Netw Open. 2022;5(9):e2229787. doi:10.1001/jamanetworkopen.2022.29787
14. Williams GJ, Nicolaou M, Athanasiou T, Coleman D. "Suture Needle Handling in the Operating Theatre: What Is the Safest Method? A Survey of Surgical Nursing Opinion." Inj Prev. 2016;22(2):135–9. doi:10.1136/injuryprev-2015-041607
15. Kunishige J, Wanitphakdeedecha R, Nguyen TH, Chen TM. "Surgical Pearl: A Simple Means of Disarming the 'Locked and Loaded' Needle." Int J Dermatol. 2008;47(8):848–9. doi:10.1111/j.1365-4632.2008.03651.x
16. Jiang S, Li P, Yu Y, Liu J, Yang Z. "Experimental Study of Needle-Tissue Interaction Forces: Effect of Needle Geometries, Insertion Methods and Tissue Characteristics." J Biomech. 2014;47(13):3344–53. doi:10.1016/j.jbiomech.2014.08.007