Adjustable Sutures in Strabismus Surgery

Why use adjustable sutures?

Allows binocular alignment to be refined after strabismus surgery

Useful in patients in whom standard surgical dosages may not apply i.e. complicated strabismus surgery such as re-operations, orbital fracture, Graves orbitopathy

Adjustable suture technique

• Advantages– Reduce rate of re-operations

• Disadvantages– Muscle slippage (7-41% when adjustable suture

surgery performed on IR)• Function of:

– Magnitude of recession performed– Nature of strabismus (↑ with fibrotic muscles)– Specific muscle (IR and MR)

– Generally tied within 24 hours of initial procedure

Semi-adjustable suture procedure

• Co-developed by Spielmann & Campo

• 1st described in 1993

• Aim: decrease the incidence of postoperative muscle slippage yet retain advantages of adjustable suture surgery

• Involves suturing the corners of the muscle firmly to the sclera at the desired recession point but also placing an adjustable suture through the centre of the muscle

Kushner

This study evaluates the procedure wrt muscle slippage

In 2000 it became his standard technique for: Recessing the IR in those patients who he wished to

do an adjustable suture If recessing MR > 12 mm from limbus

Method I

2 groups:1. Primary treatment group= never undergone

surgery OR had but had not previously slipped muscle– 57 patients on 61 muscles– 55 IR and 6 MR

2. Secondary treatment group= semiadjustable suture suture on muscles but had slipped muscle– 7 patients

Primary outcome: occurrence of muscle slippage within 6-months after surgery

Method II

• After the muscle was disinserted, the 2 corner sutures were sewn through the sclera at desired recession distance ~ 5mm apart with needle tracks directed toward each other – Bunches muscle at new insertion– Permits centre of muscle to sag 1-2mm

• Double-armed suture securing centre of muscle was brought out through insertion and secured with 6.0 polyglactin cinch & tightened to level of 2 corners

• Reference knot ~ 30-50 mm anterior to cinch

Method III

Postoperative alignment performed on the morning after surgery

After adjustment, the distance between the cinch and the knot is measured again, the difference representing the amount of muscle adjustment

Criteria for muscle slippage

“Suspect” if:1.Angle of misalignment changed by > 4 Δ in the

direction away from the field of action of the muscle between the measurement taken immediately after post operative suture adjustment to 6 month outcome

2.Versions demonstrated > 1 unit of change in the direction of ↑ underaction (5 point scale 0 to -4) from the 1-week r/v to 6 month outcome

Surgically explored (n=4) If not surgically explored, counted as slipped

muscle

Results

Primary treatment group n=0 had muscle slippage

Secondary treatment group n=1 had muscle slippage

51 year old male Left orbital floor # with IR entrapment 3 prior adjustable suture procedures on IR Found 13.5 mm from insertion Advanced using non-adjustable technique

Limitations of Semiadjustable suture

Limited efficacy for ↑ recession, target an initial overcorrection

Short Tag Noose Technique for Optional & Late Suture Adjustment

Aim: to evaluate a new technique which allows the second-stage suture adjustment to be skipped or delayed if the immediate postoperative alignment is satisfactory

Evaluate for:1. Alignment2. Reoperation3. Complications

Method

Retrospective studySimple and complex strabismus surgeryAll patients treated by a single surgeon from

2005-2008 were evaluated

Method II

Fornix incisionRecession: standard hang-backResection: extra 1-3mm of muscle resected

and allowed to hang back by same amount to allow for an ↑ or ↓ at adjustment

Standard adjustable-suture sliding nooseNoose sutures were trimmed to 3mm (short

tag noose) and buried under conjunctiva

Method III

Patient assessed in recovery room 1-2 hours ± adjusted after procedure and > 24 hours

• Alignment success:1. ≤ 10 horizontal2. ≤ 6 Δ vertical

Alignment Results at 2 months• 120 procedures– Children n=27 (22.5%)– Adults n=97 (80.8%)

Post operative adjustment n=65 Same day n=56 (46.7%) Performed or repeated after ≥ 2 days n=18 (15.0%)

Horizontal VerticalAlignment Success

81.0% 70.7%

Re-operation rate

10.0% 19.0%

Reoperation Results

No statistical difference in: Success or re-operation rate for simple or complex

strabismus Success rates in time patients adjusted Success or re-operation rate with children & adults

Complications

Slipped muscle n=1Granuloma n=2Recurrence of diplopa n=1