Sutures, Instruments and Kit — A Working Guide

Choosing the right material, knowing what to ask for, and sounding like you've been there.

This is the practical layer that sits underneath every operation and that nobody formally teaches. It is written for the registrar who knows the anatomy and the steps but wants to stop hesitating when the scrub nurse asks "what suture?"

Last reviewed: August 2026. Suture handling characteristics are stable, but practice varies considerably between units and surgeons. Where this guide gives a default, treat it as a reasonable starting point, not a rule — ask your consultant what they use and why.

---

PART ONE — SUTURES

---

1. The Four Questions

Every suture choice answers four questions:

1. Does it need to dissolve? — absorbable vs non-absorbable
2. How long does the tissue need support? — days, weeks, or forever
3. Is infection a concern? — monofilament vs braided
4. What is the tissue? — determines needle type and suture size

Get those four right and the specific brand matters much less than people pretend.

---

2. Absorbable vs Non-Absorbable

Absorbable sutures lose tensile strength and are then broken down — by hydrolysis (synthetic) or proteolysis (natural). Two separate timelines matter and people conflate them:

• Tensile strength half-life — when the suture stops doing its job
• Complete absorption — when the material physically disappears

The first is what you care about clinically. A suture that is fully absorbed at 90 days but has lost all strength by day 10 is no use for fascia.

Non-absorbable sutures retain strength indefinitely (or near enough). Used where permanent support is needed — mesh fixation, vascular anastomosis, tendon — or where the suture will be removed.

---

3. Monofilament vs Braided

The practical consequence: in a contaminated field — perforated bowel, abscess, infected mesh — reach for monofilament. In a clean field where you want a secure knot and good handling, braided is fine.

---

4. Suture Sizing (USP)

Counterintuitive and worth being certain about:

Larger → smaller:

5 · 4 · 3 · 2 · 1 · 0 · 2-0 · 3-0 · 4-0 · 5-0 · 6-0 · 7-0 · 8-0 · 9-0 · 10-0

More zeros = thinner. So 5-0 is much finer than 2-0, and 1 is thicker than 0.

---

5. The Sutures You Will Actually Use

Absorbable

Catgut (plain and chromic) is no longer available in the UK and EU — withdrawn over BSE transmission concerns. It still appears in older textbooks and older consultants' vocabulary. If asked, know it was a natural absorbable material degraded by proteolysis with a marked inflammatory response.

Non-absorbable

---

6. Needles

More marks are lost on needles than on suture material.

Point type

The one-line version: cutting for skin, round-bodied for everything inside, blunt for fascia and friable solid organs.

Curvature

Loop sutures (e.g. 1 PDS loop) have the needle swaged to a doubled strand — used for mass closure so you can anchor without a knot at one end.

---

7. What to Use Where — Quick Reference

Abdominal wall

Bowel

Hernia

Vascular

Always double-armed, always monofilament, always non-absorbable. Follow the curve of the needle; never force it through arterial wall.

Other

---

8. Knots and Throws

• Braided sutures hold with fewer throws — 3 to 4 is usually sufficient.
• Monofilament is slippery and has memory — 5 to 6 throws minimum, and more for Prolene.
• Barbed sutures need no knot but must not be back-tracked — cut flush and bury the tail.
• A surgeon's knot (double throw first) resists slippage while you place the second throw — useful under tension.
• Square knots, not granny knots. A granny knot slips under load and is a genuine cause of anastomotic leak and haemorrhage.
• Tie with the tissue, not against it — the knot should sit down without blanching the tissue. Tissue that blanches is tissue that will necrose.

---

PART TWO — INSTRUMENTS

---

9. Scalpels

Always pass a scalpel in a kidney dish or neutral zone, never hand to hand.

---

10. Forceps (Tissue Grasping)

The rule: toothed for skin and fascia, atraumatic (DeBakey) for bowel and vessels. Crushing bowel with toothed forceps is the classic novice error and it shows.

---

11. Scissors

Never cut suture with Metzenbaums. Blunting a pair of Metz in front of the scrub nurse is a memorable way to be remembered.

---

12. Haemostats and Clamps

Non-crushing on the side you're keeping, crushing on the specimen side. Get this the wrong way round and you have devitalised the bowel you are about to anastomose.

---

13. Grasping Instruments

---

14. Retractors

Hand-held

Self-retaining

---

15. Needle Holders

Hold the needle at two-thirds along from the tip, at right angles to the holder. Load it in the tip of the jaws, not the heel.

---

16. Laparoscopic Instruments

Port sizes: 5 mm (most instruments), 10–12 mm (camera on some systems, stapler, clip applier, specimen retrieval). Close fascia on any port ≥10 mm to prevent port-site hernia.

---

17. Staplers

Types

Cartridge colours (Endo GIA / tri-staple — check your system, colours vary by manufacturer)

Get this wrong in either direction and you have a problem: too short a staple on thick tissue tears through and bleeds or leaks; too tall a staple on thin tissue fails to appose and leaks. Feel the tissue, and when in doubt go one size taller.

Always allow the stapler to compress for 15–30 seconds before firing — this allows fluid to displace and improves staple formation.

---

18. Energy Devices

Key safety points:

• Cutting mode — continuous waveform, less coagulation. Coagulation mode — interrupted waveform, more heat.
• Return plate over well-perfused muscle, away from bony prominences, scars and metal implants. Burns occur from increased current density at a partially detached plate.
• Cardiac devices: prefer bipolar; if monopolar essential, short bursts, plate sited so current does not cross the device, post-operative check.
• Ultrasonic blades stay hot for several seconds after activation — a common cause of inadvertent injury.

---

19. Mesh

Never place bare polypropylene in direct contact with bowel — adhesion, erosion and enterocutaneous fistula are the consequence.

---

20. Drains

Evidence position: routine drainage after most abdominal surgery — including colorectal anastomosis and cholecystectomy — does not reduce complications and is discouraged by ERAS protocols. Drain when there is a specific indication (dead space, pancreatic anastomosis, infected cavity, bile leak concern), not by habit.

---

PART THREE — WALKING INTO A CASE

---

21. What to Ask Before You Scrub

If you're returning to operating after time away, these five questions save you every time:

1. "What's your preference for closure here?" — pre-empts the mid-operation guess.
2. "Which stapler and cartridge do you use for this?" — colours and preferences vary between units.
3. "Do you want a drain?" — and if so, which and where.
4. "Any kit I should know about that's changed?" — energy devices and mesh brands turn over quickly.
5. "How do you like the patient positioned?" — asked before the patient is asleep, not after.

None of these make you look inexperienced. Asking them makes you look like someone who has been in a lot of theatres and knows preferences differ.

---

22. Common Trays — What's Usually In Them

General set: scalpel handles, DeBakey and toothed forceps, Mayo and Metzenbaum scissors, Spencer Wells and mosquito clips, needle holders, Langenbeck and Morris retractors, Allis and Babcock, sucker, diathermy.

Laparotomy set: as above plus Deaver and Kelly retractors, Balfour self-retainer, bowel clamps (Doyen, crushing), long instruments, malleable retractors, packs.

Laparoscopic cholecystectomy: Veress or Hasson, 10 mm and 5 mm ports, 30° scope, Maryland dissector, hook diathermy, Johann graspers, clip applier, endobag, irrigation-suction.

Appendicectomy (lap): three ports, graspers, hook, Endoloop or stapler, endobag.

Hernia (open): general set, Langenbeck, self-retainer, mesh, 2-0 Prolene.

Emergency laparotomy: laparotomy set, wound protector, staplers with a range of cartridges, stoma kit, large packs, cell salvage if available.

---

23. A Note on Returning to Operating

Skills degrade less than confidence does. The things that genuinely fade after a year away are speed, instrument vocabulary, and the automatic knowledge of what comes next — not judgement or anatomy.

Practical things that help:

• Ask for a supported return — most deaneries have a formal returning-to-practice framework (SuppoRTT in England), with funded refresher time, simulation, and a phased return. Use it; it exists for exactly this.
• Start with cases you know well. Confidence returns fastest with three straightforward lap choles, not one difficult redo.
• Say what you're doing out loud while operating for the first few lists. It slows you slightly and organises your thinking considerably.
• Watch one before doing one for anything you haven't done in over a year. Nobody thinks less of a registrar who says "I'd like to see one first" — and everyone notices the one who doesn't.
• Check what changed. Guidelines, kit, and unit protocols move in a year. Ask the scrub team what's new — they always know first.

---

This guide reflects general UK practice as of August 2026. Instrument names, suture preferences, stapler cartridge colours and mesh availability vary between manufacturers and between units — always confirm locally. Educational resource; not a substitute for supervised training or clinical judgement.