Adjustable suture strabismus surgery - Overview Part 1 - Christolyn Raj Adjustable suture strabisumus surgery

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

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

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

Adjustable suture strabisumus surgery 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

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 Some studies report post op nausea 48-85% greater in kids – refs 11, 23 …imp that anaetetists minimise risk to decrease risk of aspiration -factors that are imp : anxiety, opiod use, aviding NO , ketamine Longer acting muscle relexants can delay post-op examn b/c have residual neuromuscular blocakade…also loger acting muscle rexaants require reversal with acetylchloinesterase inhibitors whch casue n & v Wrt analgesia – ckearly these pts need good intraop & post op analgesia …but opiods a prob , narcotics ie; morphime increases n &v , Adjustable suture strabisumus surgery

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 Beware of high dosese of metcoparmide causing extrapyramidal se’s Sedatoon protocol dosease ..propofol 1-3mg/kg is a full induction dose & s often reqd As an adjunct topical tetracine Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery 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

Adjustable suture strabisumus surgery Basic adjustable suture techniques. (a) Bow tie technique: the sutures are tied together in a single-loop bow tie similar to a shoelace. (b) Sliding noose technique: a noose is created by tying a separate piece of suture around the scleral sutures. Reproduced with permission from Hunter et al.84 Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery 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 Semi adjustble – es for ir muscle which has incid of slippage 7-41% -wrt uthors – adjustment perf 1-2hrs post in recov rm …in some case adj 1 wk ;ate - Also authors make an impt pt re: imp to know when to stop adjusting…adj >2mm should be avoided except in unusul cases such as restructuve strab…if there is no change after an adj then consider other factors – orbital restriction etc. Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery Semiadjustable sutures showing that the corners of IR muscle are sutured firmly to the sclera and the center of the muscle is placed on an adjustable suture. Reproduced with permission from Kushner Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery Short tag noose technique showing the fornix incision (F), trimmed pole sutures (P), and trimmed noose (N) buried under the conjunctiva. Reproduced with permission from Hunter et al.84 Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery Complications *Intra-adjustment complications : Nausea& vomiting oculucardiac reflex possible bradycardia Syncope *Postoperative healing process may be very inflammatory : conjunctival suture granulomas etc Adhesions Cxs assc adj sutures rare Can be reduced avoiding speculum , using bnx , supine positioning Adjustable suture strabisumus surgery

Adjustable suture strabisumus surgery 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 In this summry reop raed 14-20% Adjustable suture strabisumus surgery