The short adjustable suture

The short adjustable suture Andrew S. Budning,* MD, CM, MSc, FRCS(C); Catherine Day,{ OC(C); Alphonse Nguyen,{ OC(C) ABSTRACT N RE´SUME´ Objective: To describe a new, adjustable suture technique for strabismus surgery that is safe and effective and allows for adjustment during the postoperative week only when required. Design: Retrospective review. Participants: A total of 304 patients, of which 149 were male and 155 female, with an age range from 4 to 89 years and a median age of 42 years. Methods: All patients treated with the short adjustable suture technique between September 2007 and April 2009 were reviewed retrospectively. Details of cause, complexity and reoperation, operative success, requirement for adjustment, and success of adjustment were collected. Success was defined as horizontal deviation ƒ 10 prism diopters (PD) and vertical deviation ƒ 6 PD. Results: Overall, 84% of horizontal deviations and 74% of vertical deviations were treated successfully with 1 operation. Twenty-one adjustments were performed. Complications included 1 slipped slip knot and 6 conjunctival or Tenon cysts. Conclusions: The short adjustable suture is a safe and effective variation of the standard slip-knot adjustable suture technique. It allows for adjustment up to 6 days postoperatively with minimal patient discomfort. When adjustment is not indicated, the suture can be left in place to absorb. Objet : Description d’une nouvelle technique se´curitaire et efficace d’ajustement des sutures pour la chirurgie du strabisme, qui permet le rajustement dans la semaine qui suit la chirurgie, au besoin seulement Nature : E´tude re´trospective. Participants : En tout 304 patients : 149 masculins et 155 fe´minins, dont les aˆges variaient entre 4 et 89 ans, avec une moyenne de 42 ans. Me´thodes : Examen re´trospectif de tous les patients traite´s avec la technique bre`ve d’ajustement de la suture entre les mois de septembre 2007 et avril 2009. On a note´ en de´tails la cause, la complexite´ et la re´ope´ration, la re´ussite de la chirurgie, le besoin d’ajustement et la re´ussite de l’ajustement. La re´ussite a e´te´ de´finie comme e´tant la de´viation horizontale ƒ 10 prismes-dioptries (PD) et la de´viation verticale ƒ 6 PD. Re´sultats : Somme toute, 84 % des de´viations horizontales et 74 % des de´viations verticales furent traite´es avec succe`s en une seule ope´ration. On a pratique´ 21 ajustements. Les complications comprirent 1 glissement du nœud coulant et 6 kystes conjonctivaux ou de Tenon. Conclusions : La suture ajustable courte est une varie´te´ se´curitaire et efficace de la technique d’ajustement standard par nœud coulant. Elle permet l’ajustement jusqu’a` 6 jours apre`s l’ope´ration avec un minimum de de´sagre´ment pour le patient. Lorsque l’ajustement n’est pas indique´, on peut laisser la suture se re´sorber sur place.

A

djustable sutures have been used since 1977.1 The goal of the adjustable suture is to allow an additional opportunity to realign the eyes soon after strabismus surgery.2 Currently described procedures for adjustment require adjustment for all patients, typically within 24 hours after surgery. This procedure is often uncomfortable for the patient and stressful for the surgeon.3,4 We have used the slip-knot adjustable suture technique3,4 with a short permanent tie. This technique provides all the advantages of the slip-knot adjustable suture technique while requiring adjustment of the suture only in those cases where adjustment is felt to be of benefit. Similar modifications of the slip-knot technique have been described for use as adjustable sutures.5–7 With our

technique, no additional scleral passes or other manipulations were required, and adjustments were performed up to 6 days postoperatively. Our objective was to develop an adjustable suture technique that allows for adjustment only when required, that can be adjusted for up to 6 days post surgery, and that remains safe and effective.

From *the University of Toronto, the Credit Valley Hospital and the Hospital for Sick Children, Toronto, Ont.; and {Budning Eye Institute, Mississauga, Ont.

Correspondence to Andrew S. Budning, MD, 305-2300 Eglinton Ave. W, Mississauga, ON L5M 2V8; [email protected]

Presented at the Canadian Ophthalmological Society Annual Meeting, Toronto, Ont., June 20–23, 2009

METHODS Adjustable slip-knot short-suture end technique The muscle (typically recessed) is hung back to the appropriate position. A slip knot of 6-0 vicryl suture is then tied about the long ends of the suture. The suture originates where it is attached to the muscle, then courses a

This article has been peer-reviewed. Cet article a e´te´ e´value´ par les pairs. Can J Ophthalmol 2010;45:359–62 doi:10.3129/i10-012

Originally received July 23, 2009. Final revision Oct. 4, 2009 Accepted Jan. 13, 2010 Published online June 28, 2010 CAN J OPHTHALMOL—VOL. 45, NO. 4, 2010

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The short adjustable suture—Budning et al. path through the scleral tunnels and the slip knot, to the long free ends. A 4 mm length of suture is clamped with a needle driver just anterior to the slip knot and tied permanently (Fig. 1). This leaves the slip knot at the insertion with the muscle hanging back, and a 4–6 mm end of short suture with a permanent tie. There is a length of suture anterior to the slip knot available to slide the slip knot along, to allow for recession or advancement of the muscle. In the case of a muscle resection, the suture is passed through the sclera 1–2.5 mm anterior to the insertion, allowing for additional advancement past the insertion if desired. Should the slip knot loosen, the permanent tie will limit slippage of the muscle. This technique allows for up to 4–6 mm of additional recession or advancement of the recessed (hang-back) muscle to the level of the initial insertion, or slightly anterior to the insertion in the case of a muscle resection. The short-end suture is then tucked under the conjunctiva and the conjunctiva is closed in a standard fashion. If adjustment is necessary, it can be carried out for up to 6 days post surgery. The limiting factors remain muscle readhesion to the globe and the beginning of disruption of the absorbable suture used (6-0 Vicryl). Procedure for adjustment A small amount of lidocaine 1% is injected under the conjunctiva at the edge of the wound under slit-lamp or microscope control to anaesthetize the area. The suture is then teased out with tying forceps. If advancement is desired, the suture is clamped with the needle driver between the suture end and the slip knot. A tying forceps is then used to slide the slip knot to the desired position. The eye movements are re-evaluated and the procedure is repeated as required until the movements are felt to be at

goal. If additional recession is desired, the slip knot is slid toward the permanent tie. Study design All charts for patients treated for strabismus with the short-end adjustable suture technique from September 2007 to April 2009 were reviewed retrospectively. All procedures were performed by 1 surgeon (Andrew Budning). Details of cause, complexity, and reoperation were collected. Success was defined as horizontal deviation ƒ 10 prism diopters (PD) and vertical deviation ƒ 6 PD. RESULTS

Three hundred and twelve patients were treated. Eight patients were excluded because of insufficient data. One hundred and forty-nine were male and 155 were female. The age range was 4–89 years, with a mean of 41 (SD 19) years. The median age was 42 years. The average time to most recent follow-up was 145 (SD 174) days, with a median time of 112.5 days. The causes for strabismus were basic, restrictive, and neurologic, as detailed in Table 1. Of the 304 cases, 252 were treated for horizontal deviations, 55 for vertical deviations, and 3 for a combination of vertical and horizontal deviations (Table 2). For 194 patients, the current surgical treatment was their first. For 73, it was the second strabismus repair, for 29, the third and for 8, the fourth (Table 3). Among patients treated for horizontal deviations (n 5 252), 84% had a final deviation ƒ 10 PD with a mean of 7.2 (SD 7.4) PD. Among patients treated for vertical deviations (n 5 55), 78% had a final deviation Table 1—Causes for strabismus Cause

No. patients

Basic sensory Infantile/childhood

203

Traumatic cataract

20

Restrictive Trauma

4

Thyroid

18

Retinal detachment

4

Postretrobulbar injection for cataract

2

Neurologic

Fig. 1—A 4–5 mm end of 6-0 Vicryl suture is left anterior to the slip knot (located at the insertion). The ends of the suture are tied permanently prior to trimming the excess suture. This leaves a length of suture anterior to the slip knot available to slide the slip knot along to allow for recession or advancement of the muscle.

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III palsy

7

VI palsy

10

IV palsy

26

Childhood meningitis

4

Optic nerve injury

1

Duane’s syndrome

4

Stroke at birth

1

Table 2—Number of strabismus repairs separated by vertical, horizontal, and combination Direction of deviations Horizontal Vertical Combination (included in both groups above) Note: ET, esotropia; XT, exotropia.

No. patients 106ET + 146XT 5 252 55 3

The short adjustable suture—Budning et al. ƒ 6 PD with a mean of 4.8 (SD 3.7) PD (Tables 4 and 5). Three patients (n 5 3), included in the horizontal and vertical groups above, were treated for both horizontal and vertical deviations. All (100%) had a final horizontal deviation ƒ 10 PD with a mean of 6 (SD 2.0) PD, and a vertical deviation ƒ 6 PD with a mean of 2.7 (SD 3.0) PD. Only 23 adjustments (adjusted group) were performed on 19 of the 304 patients in the study. Two of the 19 patients in the adjusted group had both a horizontal and a vertical adjustment (a total of 4 muscles adjusted on the 2 patients). Two other patients in the adjusted group were adjusted a second time (a total of 4 adjustments on 2 patients) (Table 5). Ten of the 19 patients were adjusted 1 day postoperatively. One was adjusted 4 days postoperatively, 7 were adjusted 5 days postoperatively, and 1 was adjusted 6 days postoperatively (Table 6). The 2 patients requiring a second adjustment had their final adjustment performed on day 4 (patient 2 in Fig. 2) and day 5 (patient 3 in Fig. 3). Horizontal eye alignment improved from a deviation . 10 PD preadjustment to a deviation ƒ 10 PD post adjustment in 11 of the 16 patients (69%) (Fig. 2). Vertical eye alignment improved from a deviation . 6 PD preadjustment to a deviation ƒ 6 PD post adjustment in 4 of the 5 patients (80%) (Fig. 3). Patients 1 and 2 had both horizontal and vertical adjustments. A second adjustment was performed for patient 2 in Fig. 2 and for patient 3 in Fig. 3 (only the initial preadjustment and final post–second adjustment values are included in Figs. 2 and 3 for the 2 patients requiring 2 adjustments).

Complications Two patients were taken to the operating room for readjustment, 1 because of age (8 years old) and 1 adult because of inability to cooperate. One patient had the slip knot untie; this was corrected at the slit lamp by retying the slip knot. Six patients developed small conjunctival or Tenon cysts, requiring needle puncture (1 recurred). Difficulties with the technique include the fact that some of the slip knots remain tight and can be difficult to slide. Occasional slip knots remain loose. No slip knot was noted to slip postoperatively. CONCLUSIONS

Adjustable sutures have been used for strabismus since 1977.1 This technique was described initially as a method of allowing an opportunity to refine eye position post strabismus surgery, providing a better final result. Since that time, a number of different techniques, including standard and modified bow tie and slip knot, have been described.3,4 Despite differences, the goal of the procedure has remained focused on improving the outcome post strabismus surgery. The short-end adjustable suture technique was developed in an effort to continue the trend of improving outcome, as well as maximizing patient comfort prior to,

Table 3—Number of current operations/reoperations for strabismus Current operation number

No. patients

First

194

Second

73

Third

29

Fourth

8

Table 4—Preoperative and postoperative ocular deviations (all patients) Preop, mean (SD)

Postop, mean (SD)

Horizontal esotropia

29 (13)

7.2 (7.4)

Horizontal exotropia

36.5 (17)

6.9 (6.5)

Vertical gazes (Hypo/HT)

18 (12.2)

Fig. 2—Preadjustment to postadjustment change in horizontal deviation. Improved success post adjustment was achieved in 11 of 15 patients, or 69% (defined as ƒ10 prism diopters [PD]). Patient 2 was adjusted a second time to achieve success.

4.8 (3.7)

Note: Preop, preoperative; Postop, postoperative; Hypo, hypotropia; HT, hypertropia.

Table 5—Outcome success (all patients) Direction of initial deviation Horizontal (success: ƒ 10 PD)

No. patients (%) 212 (84)

Vertical (success: ƒ 6 PD)

43 (78)

Note; PD, prism diopters.

Table 6—Postoperative days to suture adjustment No. patients

No. days

10

1

1

4

7

5

1

6

Note: 2 patients required 2 suture adjustments.

Fig. 3—Preadjustment to post adjustment change in vertical deviation. Improved success post adjustment was achieved in 4 of 5 patients, or 80% (defined as ƒ 6 prism diopters [PD]). Patient 3 was adjusted a second time to achieve success. CAN J OPHTHALMOL—VOL. 45, NO. 4, 2010

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The short adjustable suture—Budning et al. during, and post the adjustment procedure. Recognizing that adjustment is not required in the majority of patients,5–7 it was felt that a technique whereby adjustment could be done when needed and at the most opportune time to maximize results would lead to improved outcomes. This rationale remains the same as that used by Engel and Rousta5 and Awadein et al.6 in their more recent descriptions of adjustable sutures in children. The techniques described in their papers showed success rates similar to ours, although the percentage of patients requiring adjustment was lower in the current study. By contrast, in the current study, we demonstrated that simply folding the short end of the suture under the conjunctiva is safe and effective, minimizing manipulation and scleral suture passes. In addition, we extended the time between surgery and adjustment to up to 6 days for adults and 4 days for 1 child, with no adverse effects. Postoperative drift remains a major limitation to successful eye alignment. In summary, the short-end adjustable suture technique described in this paper offers many advantages over the traditional technique. One of the most important features is that it allows for adjustment of the muscle position only when necessary. A second important feature is the time for adjustment.7–9 With the standard slip-knot or bow-tie technique,2–4 adjustment must be carried out on the day of surgery or at latest the following morning. With the short-end technique, adjustment is possible at the end of the case (based on forced ductions), later that day, or at any time over the following 6 days for adults or the following 3–4 days for children.9 In pediatric cases, we have found it necessary to reanaesthetize the patient for a few minutes to allow for adjustment.5–7,9 Finally, multiple adjustments are possible, limited only by readhesion of the muscle to the globe and suture absorption. This allowance for delayed adjustment provides time for tight muscles post resection, or loose muscles post recession, to approach their new length–tension state prior to the surgeon making the decision to adjust or deciding on the degree of adjustment required. Additionally, this period of time allows the postsurgical inflammation to resolve partially, making it easier for the patient to open his or her eyes and cooperate in the examination and adjustment. Patient comfort appeared to be improved with delayed adjustment, compared with same-day adjustment. Other situations in which this technique has been helpful include complex reoperations, tight resections, and cases

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in which multiple adjustable sutures would be of benefit because of both horizontal and vertical misalignment. This technique has been used in pediatric patients (20 to date , 16 years of age),5,6,9 and all have tolerated the procedure and have healed well. One required adjustment, which was performed under mask anaesthesia without incident 5 days postoperatively. In conclusion, this technique is a safe and effective alternative to the standard adjustable suture technique. Success rates are similar to those described in the literature.2,4–9 Future plans As this on-going study continues, we hope to better determine the type of patient who would most benefit from adjustment with this procedure, as well as the most opportune time for adjustment. Additionally, we will be increasing the number of children treated with adjustable sutures and refining the process of adjustment for them. Finally, we will begin to collect data on patient comfort and stress related to this adjustable suture technique. The authors have no proprietary or commercial interest in any materials discussed in this article.

REFERENCES 1. Rosenbaum AL, Metz HS, Carlson M, Jampolsky AJ. Adjustable rectus muscle recession surgery. A follow-up study. Arch Ophthalmol 1977;95:817–20. 2. Keech RV, Scott WE, Christensen LE. Adjustable suture strabismus surgery. J Pediatr Opthalmol Strabismus 1987;24:97–102. 3. Wright KW. Colour Atlas of Ophthalmic Surgery. Strabismus. Philadelphia, Pa.: Lippincott; 1991. 4. Kraft SP, Jacobson ME. Techniques of adjustable suture strabismus surgery. Ophthalmic Surg 1990;21:633–40. 5. Engel JM, Rousta ST. Adjustable sutures in children using a modified technique. J AAPOS 2004;8:243–8. 6. Awadein A, Sharma M, Bazemore MG, Saeed HA, Guyton DL. Adjustable suture strabismus surgery in infants and children. J AAPOS 2008;12:585–90. 7. Saunders RA, O’Neil JW. Tying the knot: Is it always necessary? Arch Ophthalmol 1992;110:1318–21. 8. Eino D, Kraft SP. Postoperative drifts after adjustable-suture strabismus surgery. Can J Ophthalmol 1997;32:163–9. 9. Isenberg SJ, Abdarbashi P. Drift of ocular alignment following strabismus surgery. Part 2: using adjustable sutures. Br J Ophthalmol 2009;93:443–7. Keywords: strabismus, suture techniques, humans, oculomotor muscles, adults, children