Adjustable suture strabismus surgery - Overview Part 1 -

1. Adjustable suturestrabismus surgery- Overview Part 1 - Christolyn Raj Adjustable suture strabisumus surgery

2. Overview Part 1 • Adjustable sutures • Indications • Patient selection • Anaesthetic considerations • Techniques • Complications Adjustable suture strabisumus surgery

3. Adjustable sutures in strabsmus surgery • Principle : to secure EOM to sclera with a sliding knot , then when pt is awake , the length of suture b/w attachment site and muscle may be shortened or lengthened • First described by Claude Worth , first practised by Jampolsky 1975 • No prospective RCTs to date on selective advantage of adjustable sutures • Few reports on use of adjustable sutures on children • Adjustable sutures in strabismus surgery . Hunter, D. Dingeman RS et al. J Paed Opthal 2009. • Number of surgeons decribe adjustable sutures in adults to improve immediate post-op alignment [refs 3, 17, 22, 26, 30-32] • Summary by Hunter, Dinegeman et al., promote use of adjustable sutures on ALL adults , including those with comitant strabismus & no prior surgery • Authors also describe use in children who met select criteria Adjustable suture strabisumus surgery

4. Standard indications for adjustable suture strabismus surgery • Restrictive strabismus eg: TED • Previous trauma or surgery • Slipped, lost, disinserted muscles • Incomitant deviations eg : Duane’s syndrome , MG • Any longstanding, complex strabismus Adjustable suture strabisumus surgery

5. Patient selection • Adjustable sutures can be used with recessed or resected muscles and also been successfully described on superior oblique tendon . Goldenberg-Cohen N, et al. 2005. Strabismus 13;5-10. • Most surgeons advocate adjustable suture technique in children aged 12 yrs & older • and only younger if co-operative & may require two stages of anesthesia • Active participation of parents is a key factor (Dawson et al. 2001) Can perfom “Q-tip” test to identify suitable pts – consists of touching a cotton tip to the MR or LR aspect of the unanesthetized bulbar conjunctiva as a pre- test tolerability • If patient fails Q-tip test : consider non-adjustable suture surgery or arrange for back-up sedation Adjustable suture strabisumus surgery

6. Anaesthetic considerations 1). Recovery of extraocular muscle function -GA: EOM function recovers when pt awakes -LA: short acting agents require 5hrs minimum for motility to recover 2). Patient comfort & alertness in recovery -pre-medication: for post-op nausea -induction with propofol preferable , shorter acting muscle relaxants preferable -avoid opiate analgesia which may cause sedation & nausea -topical tetracaine is often sufficient -ketorolac early intraop is another option /7 is m.effective Adjustable suture strabisumus surgery

7. Anaesthetic considerations 3). Post-op nausea & vomiting -ondansetron is very effective & has few SE’s -use with dexamethasone may augment effects of ondansetron 4). Sedation protocol for suture adjustment -mainly for unco-operative pts -inform anaethetist -should be monitored in recovery room setting to ensure airway & basic monitoring equipment is readily available -may need propofol induction dose Adjustable suture strabisumus surgery

8. Surgical techniques Limbal vs fornix approach • Limbal appoach provides broad exposure but requires conjunctival closure post suture adjustment • Fornix approach may be more comfortable as sutures are covered Technique Bow tie • Sutures ae tied together in a single-loop bow-tie like a shoelace • At adjustment the bow is untied , muscle adjusted & re-tied, bow cut & converted to a square knot Sliding-noose • sutures are passed through scleral tunnels emerging <1mm apart , a noose is created by tying a separate piece of suture around the scleral sutures Adjustable suture strabisumus surgery

9. Adjustable suture strabisumus surgery

10. Surgical techniques Semi-adjustable sutures • Described by (Kushner et al.) to reduce muscle slippage whilst preserving potential for adjustment • Involves suturing corners of muscle to sclera & placing centre of muscle on adjustable Authors’ preferred technique • Describes “noose” suture • For adjustable recession standard hangback doses used • For adjustable resection an extra 1-3mm muscle is resected , then muscle allowed to hang back by same amt • After the sutures are passed , they are pulled to original insertion then these sutures are secured to each other with an overhand knot- these joined sutures are ‘ple sutures’ • For the adjustable noose , an absorbable suture is used , placed underneath the pole sutures & wrapped around a second time, finally tying a square knot to prevent slippage • At adjustment the bow is untied , muscle adjusted & re-tied, bow cut & converted to a square knot Adjustable suture strabisumus surgery

11. Adjustable suture strabisumus surgery

12. Adjustable suture strabisumus surgery

13. Complications *Intra-adjustment complications : • Nausea& vomiting • oculucardiac reflex • possible bradycardia • Syncope *Postoperative healing process may be very inflammatory : • conjunctival suture granulomas etc • Adhesions Adjustable suture strabisumus surgery

14. Conclusion • Adjustable sutures provide a second chance to improve outcomes of initial strabismus surgery • However…. • They can add to complexity of case • Require appropriate patient selection • Evidence to validate their advantage over convential surgery is still not universally acknowledged • Difficult learning curve involved Adjustable suture strabisumus surgery