FP1744 : Outcome of Modified Engel ’S Technique of Adjustable Sutures in Children

Dr. Muralidhar Rajamani, R10440, Dr. Vaishnavi, Dr. Sekhar Michael Chidambaram A.P.

Dr. MuralidharRajamani (presenting author- AIOS membership no. R10440)

Dr. Vaishnavi M

Dr. Sekar Michael

Dr. Chidambaram P

The Eye Foundation

Coimbatore

Introduction:

A number of factors influence the outcome of strabismus surgery  including the orbital biomechanics, AC/A ratio, fusional potential, angle of strabismus to name a few. There are yet many poorly understood factors affecting the outcome. Adjustable sutures allow the surgeon to reliably improve the immediate postoperative outcome. A number of retrospective trials have shown that adjustable strabismus surgery does improve the surgical success and reduce resurgery rates. A recent study has also shown that attainment of the target angle in the immediate postoperative period does influence the long term outcome favorably and such is more likely with the use of adjustable suture techniques.  One prospective randomized trial did show that single stage adjustable strabismus surgery gave superior success to two stage and conventional strabismus surgery in adults. 1-3

There has been some reluctance in the use of adjustable suture techniques in children. Understandably there are issues in getting the child to cooperate for evaluation in the immediate postoperative period. Further the need for general anesthesia to tie off the sutures even when adjustment is not needed makes this option less attractive. Recently Engel and other authors have described techniques that bury the sutures via scleral passes. This obviates the need for a second visit to the operating room should adjustment not be needed. A few studies in children have shown improved success rates as well.4-5We have modified Engel’s technique (originally described as a slip knot technique) to use a bow tie technique and bury the sutures by additional scleral passes as shown in the figure below

We also use a hemi-hang back suture for the lateral rectus as described by Engel et al. However unlike Engel who left his pole sutures in scleral passes, we use a bow tie knot as described above

There is no place where technique has been described

Material and Methods:

            The first author has entirely shifted to using adjustable sutures in children with the above described technique using a fornix incision. All patients < 10 years of age and operated between Aug 2015 to March 2016 were included for the study. Preoperatively the strabismus measurements were done with the patients optical correction in place and measurements were made with loose prisms for distance (primary, up and downgaze in all patients, right and left gaze also in patients with exotropia) and near (primary). A note was made of oblique dysfunction if any.  All patients underwent a comprehensive ophthalmic evaluation including a detailed examination of the anterior and posterior segment and cycloplegic correction. All patients had been evaluated and treated for amblyopia when needed.  The surgical technique is as described in the introduction. 6-0 vicryl was used to secure the muscle and inferior fornix incisions were left unsutured.Patients were evaluated on the next day. Most patients were evaluated on the mother’s lap and some in the department play area using small toys and videos as fixation targets. For patients with exotropia we aimed for an esotropia of around 6-8pd for distance and near, optimal alignment for children < 4 years of age. For patients with esotropia, we aimed for 0-8pd of residual esotropia.

Adjustment (if required) was done under intravenous ketamine and topical proparacaine. The maximum time permitted for adjustment was 72 hours after the first surgery.  Postoperatively patients were prescribed topical steroid antibiotic combination twice daily for the first five days and once daily for the next five days. Patients were reviewed the day after adjustment, at one month and at three months. The outcomes were compared with historical controls (patients < 10 years) operated by conventional surgical techniques before August 2015. The factors analyzed included the correction afforded by strabismus surgery and the anatomical success rate.

Results:

Six patients had exotropia and eleven had esotropia.  The mean age was 4.2±2.1 years. The mean preoperative deviation(eso)was 54.9±17.5 pd.The mean preoperative deviation (exo) was 46.8 ±9.3pd. One patient had bilateral inferior oblique recession and another had bilateral superior oblique tenotomy.  The mean number of muscles operated were 3.1 ± 1.2. Overall six patients needed adjustment. The deviation at 3 months (eso) was 3.2± 6.9pd(p<0.001).All but 1patient was aligned to<10 pd.For exotropia the deviation at 3 months was 1±3.6 pd.All patients were aligned to <10 pd.In contrast the surgical success in historical controls at the three month review was 67%. Gross stereopsis could be detected in three patients with esotropia and stereopsis of 40 seconds of arc in three patients with exotropia with the remainder having gross stereopsis.

One patient did not cooperate for postoperative evaluation and only an approximate estimate of the deviation could be obtained with physical restraint. In all other patients a reliable estimate of the deviation could be obtained, though multiple attempts to obtain patient cooperation were needed. Fifteen patients were adjusted after 72 hours and the remaining two after 24 hours. In the former measurements were obtained on the day of surgery.  All adjustments were done under ketamine sedation with topical proparacaine.

Discussion:

            Our study shows that adjustable sutures are a feasible option in children and help optimize the immediate and short term outcomes of strabismus surgery. This is in agreement with other studies in this regard.4-5Our adjustment rate of 35% is also comparable to the available literature.4 We adjusted our patients as late as 72 hours. This was more for logistic reasons but we did not encounter any problems with the same.  This delay in adjustment helped us get the cooperation of the child for assessment. None of our patients who were not adjusted developed any suture related complications like suture granuloma or slipped muscle. Thus optional adjustable sutures with a bow tie appear to be a safe option in children though further studies in this regards are needed. The optional adjustable technique also obviates the need for a second visit to the operating room should adjustment not be needed.

References

  1. Zhang MS, Hutchinson AK, Drack AV, Cleveland J, Lambert SR.Improved ocular alignment with adjustable sutures in adults undergoing strabismus surgery.Ophthalmology. 2012 Feb;119(2):396-402.
  2. Sharma P, Julka A, Gadia R, Chhabra A, Dehran M. Evaluation of single-stage adjustable strabismus surgery under conscious sedation.Indian J Ophthalmol. 2009 Mar-Apr;57(2):121-5.
  3. Mireskandari K, Schofield J, Cotesta M, Stephens D, Kraft SP. Achieving postoperative target range increases success of strabismus surgery in adults: a case for adjustable sutures?Br J Ophthalmol. 2015 Dec;99(12):1697-701.
  4. Engel JM, Guyton DL, Hunter DG.Adjustable sutures in children.J AAPOS. 2014 Jun;18(3):278-84.
  5. Awadein A, Sharma M, Bazemore MG, Saeed HA, Guyton DL.Adjustable suture strabismus surgery in infants and children.J AAPOS. 2008 Dec;12(6):585-90.

 

 

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