Minimally invasive strabismus surgery (MISS) is no different from any other surgical discipline in that the desired outcome
is to increase patient comfort and quality of life and minimise unwanted complications and poor postoperative appearance.
"The size of the conjunctival incision made during strabismus surgery is one of the main factors influencing patient quality
of life, cosmesis and the function of the operated muscle. As such, some surgeons have attempted to limit the size of the
incision in order to enhance postoperative outcomes," said Dr Mojon.
"The majority of surgeons still use the traditional limbal approach to surgery, which was first described by Harms in 19491 and later popularised by von Noorden,2,3 to allow direct access to Tenon's space for horizontal muscle recession, resection or plication."
As early as 2003 Dr Mojon established MISS by exposing horizontal rectus muscles through two small radial cuts; one along
the superior and the other along the inferior margin of the horizontal muscles, allowing graded recessions and plications
to be performed. Postoperatively the openings remain covered by the eyelids, apart from during upgaze and excessive lateral
gaze. Subsequently the surgical area remains protected and out of sight. The new TRASU technique
Figure 1
|
A full description of the novel transconjunctival suturing (TRASU) technique carried out by Dr Mojon appears in The Journal
of Paediatric Ophthalmology & Strabismus 2009 Nov 2:1-5. doi: 10.3928/01913913-20091019-07. [Epub ahead of print] but here
he gives us an overview of his prospective study, which was conducted on 20 patients who had unilateral horizontal rectus
muscle surgery with a TRASU technique for primary muscle displacements of 4.5 mm or greater or for repeat muscle displacements
of 3.0 mm or greater.
"For the new TRASU technique the positioning of peri-insertional radial cuts was the same as for the MISS procedure [see Figure
1(e)]," explained Dr Mojon, "however the incision length was some 2.5 mm less than the planned muscle displacement distance."
The following steps were then carried out:
- Following insertion of two sutures in the muscle at its original insertion point it was then detached, as in Figure 1 (e)
- A curved ruler was used to press against the sclera for minimum of 10 seconds, leaving an indentation to indicate where the
muscle was to be reattached
- The distal border of the superior radial incision was then elevated and the surgeon sutured the detached end of the muscle
to the sclera at the line of indentation
- In order to pass the needle fully through the sclera it has to travel transconjunctivally
- Using forceps the needle was then pulled back through the conjunctiva.
- The suture was then knotted, securing attachment to the sclera.
- The same procedure was then repeated to secure the muscle's inferior attachment.
- The two conjunctival incisions were then closed.
Key findings
There were no complications during surgery at all and the 19 patients who returned for follow-up had no postoperative complications.
The only overt visible signs of surgery was a mild redness in 11 eyes at the end of surgery and on day one, postoperative.
At 6 months after surgery refractive error and visual acuity were not significantly different to those prior to the operation.
The incision size was 31%±11% shorter than incisions for standard MISS procedures.
What this means
"Ophthalmologists using the TRASU technique will be able to decrease the extent of tissue disruption by conducting large primary
or repeat muscle recessions, plications or advancements through an incision up to a third smaller than that performed using
the standard MISS technique," explained Dr Mojon.
"I would strongly advocate that surgeons familiarise themselves fully with the MISS technique for muscle displacement prior
to using this new method," cautioned Dr Mojon.
The study population is small and Dr Mojon agreed that further work is required to exclude increased risk of ocular penetration
employing this suturing technique.
References
1. H. Harms. Klin. Monatsbl. Augenheilk 1949;115:319-24.
2. G.K. von Noorden. Arch. Ophthalmol. 1968;80:94-97.
3. H.E. Willshaw. Trans. Ophthalmol. Soc. UK 1986;105:583-8.
4. D.S. Mojon. Br. J. Ophthalmol. 2007;91:76-82.
5. D.S. Mojon Mojon's Manual of Medicine A Cartoon Book for Daily Clinical Lie. 2009, XII, 128 p. 128 illus., Hardcover ISBN:
978-3-540-68559-3 or visit http://www.springer.com/medicine/ophthalmology/book/978-3-540-68559-3/
