Suture Materials

Classification

• Based on
  1. Absorbable vs. non-absorbable
  2. Braided (multifilament) vs. monofilament
  3. Synthetic vs. natural

• Absorbable vs. non-absorbable
  • Non-absorbable
    • Advantage
      • Longer mechanical support
    • Disadvantage
      • Nidus for stone formation in urinary tract
• Braided (multifilament) vs. monofilament
  • Monofilament
    • Advantages
      1. Less tissue dragging and tearing
      2. Less tissue reaction
      3. Reduces spread of wound infection since does not provide capillary wicking of fluids
• Synthetic vs. natural
  • Synthetic
    • Advantages
      • Less tissue reaction

Absorbable

• Monofilament
  • Catgut
    • Natural
    • Majority based on type I collagen
    • Extracted from the intestines of sheep or goats
    • Two types: plain vs. chromic
      • Chromic
        • Treated with chrome salts (brown colour) which slows absorption time and reduces tissue reaction
    • Completely absorbed within ≈70-90 days
    • Time to 50% breaking strength retention: 3-4 weeks§
    • Advantages
      1. High elasticity
      2. Good tensile strength
         • Plain catgut: 7 days
         • Chromic catgut: 14 days
    • Disadvantages
      1. Poor knot security
      2. Tissue reaction (due to foreign protein nature of catgut suture)
         • Plain catgut has more tissue reaction than chromic catgut
  • Monocryl
    • Also known as poliglecaprone
    • Synthetic
    • Completely absorbed within ≈90-120 days§
    • Identical knot performance compared with Vicryl, similar performance to PDS, and lesser performance compared with Maxon
    • High initial breaking strength, being superior to chronic gut, Vicryl, and PDS
    • Time to 50% breaking strength retention: 1 week§
    • Advantages§
      • Pliability, minimal force required to bend
      • Less out-of-package memory than maxon and PDS
  • Maxon
    • Also known as polyglyconate
    • Synthetic
    • Completely absorbed within ≈100 days
  • Biosyn (Covidien)
    • Synthetic
    • Completely absorbed within ≈90-110 days§
  • PDS (Ethicon)
    • Also known as polydioxanone
    • Synthetic
    • Completely absorbed within ≈200 days
    • Enhanced version (PDS II) has improved flexibility and handling characteristics
• Braided
  • Vicryl (Ethicon)/Polysorb (Covidien)
    • Also known as polyglactin
    • Synthetic
    • Completely absorbed within ≈60 days
    • Time to 50% breaking strength retention: 3 weeks§
  • Dexon (Covidien)
    • Also known as polyglycolic acid

Non-absorbable

• Monofilament
  • Nylon
    • Natural
  • Prolene
    • Synthetic
• Braided
  • Silk
    • Natural

Clinical implications

• Closure of urinary tract wounds§
  • Wounds of the urinary bladder wall regain strength equal to unwounded bladder wall within 21 days, based on animal studies§
    • Wounds of stomach and colon do not achieve more than 70 per cent of unwounded tissue strength after 120 days§
  • Braded, synthetic absorbale sutures (polyglactin 910 (Vicryl) and polyglycolic acid (Dexon)) should be used in the absence of infection
    • Braded, synthetic absorbable sutures are absorbed by nonenzymatic hydrolysis in a predictable manner with limited inflammatory response while gut sutures have an unpredictable absorption rate by enzymatic degradation and elicit an exaggerated inflammatory response
    • In the presence of infection, use absorbable natural fiber suture e.g. Catgut
      • Proteus species, accelerates the degradation of absorbable synthetic sutures to a greater degree than Catgut suture
    • Nonabsorbable sutures or staples should not be used in the urinary tract because predictably promote urolithiasis.
• Bladder closure§
  • 2-layered closure
    • Close mucosal layers with 3-0 Vicryl in running manner
    • Close detrusor/serosal layers with 2-0 Vicryl in running manner
• Ureteroureterostomy
  • 4-0 to 6-0 suture

Needles

• Characteristics to consider
  • Point
    • Taper vs. cutting
  • Circle
    • 1/2
    • 3/8
    • 5/8
  • Length
    • 26 mm
    • 36 mm
    • 40 mm
• Common needles
  • CT-1 (Ethicon): taper, 1/2 circle, 36mm
    • Similar needle in Covidien: GS-21
  • SH: taper, 1/2 circle, 26mm
    • Similar needle in Covidien: V-20
  • RB-1: taper, 1/2 circle, 17mm
    • Similar needle in Covidien: CV-23
  • UR-6: taper, 5/8 circle, 26mm
• Covidien
  • Urology needles are available as taper point and 5/8 circle, with lengths of 27 mm (GU-46 and HGU-46), 37 mm (GU-45) and 40 mm (GU-44).[1]

References

• Rose, Jessica, and Faiz Tuma."Sutures And Needles." StatPearls [Internet] (2020).
• Chu, C. C. Biotextiles as medical implants: 11. Materials for absorbable and nonabsorbable surgical sutures. Elsevier Inc. Chapters, 2013.
• Edlich, Richard F., George T. Rodeheaver, and John G. Thacker. "Considerations in the choice of sutures for wound closure of the genitourinary tract." The Journal of urology 137.3 (1987): 373-379