This letter is written in response to an article in the December 2011 issue of the Archives of Ophthalmology on the paradox of surgeons obtaining good results treating A- and V-pattern strabismus, convergence insufficiency and convergence excess esotropia using methods of insertion slanting recessions or biased resections that are opposite in nature. The letter's authors, Huseyin Bayramlar, MD, and Cihan Unlu, MD, say that some controversial points merit further discussion.
They note that the article's author, Dr. Burton J. Kushner, MD, mentioned that two opposite approaches exist in slanting strabismus techniques: the Bietti method and the Simonsz/von Graefe method. They point out that he correctly describes that Bietti recessed the inferior portion of the medial rectus muscle more than the superior pole for V-pattern esotropia. However, this was attributed to the wrong figure in the article, figure 4A rather than the correct 4B. In a reply to this letter, Dr. Kushner acknowledges that this is a mistake that has been previously recognized and a correction has been published.
Drs. Bayramlar and Unlu say Dr. Kushner seems to advocate for the Simonsz/von Graefe method based on what he considers to be a sound concept of ocular motor mechanics and disavows the Bietti method. However, he cites only a single study supporting the Simonsz/von Graefe method of slanting vs. at least 14 studies supporting the Bietti method.
Dr. Kushner responds that this is a misunderstanding of his position and that he advocates for neither approach. He says that what he referred to as the Simonsz/von Graefe method is based on principles that are consistent with current understanding of ocular muscle mechanics. He notes that he wrote, "Probably, insertion slanting does not have a substantial effect on the outcome of strabismus surgery . . . the effect is miniscule and is negated by sarcomere remodeling."
Drs. Bayramlar and Unlu further note that Dr. Kushner states that van der Meulen-Schot et al report good results with an insertion slanting procedure in A or V patterns when they slanted the muscle in a manner opposite to that recommended and performed by Bietti and others. However, the surgical method used by van der Meulen-Schot and colleagues is not performed with a recession or by removing the rectus muscle from the globe but is a superior or inferior tenotomy near the insertion of the horizontal rectus muscles. They say that the two methods (tenotomy near the insertion vs. slanting recession or resection procedures) are not quite the same operation.
They call for new studies on slanting of the recessed or resected rectus muscles using the Simonsz/von Graefe method of slanting. Until a controlled trial is performed comparing these two surgical approaches using slanting as opposed to tenotomy, they say we should not draw definitive conclusions as to their relative efficacy.
Dr. Kushner responds that a convincing rationale behind the Bietti method (e.g., slanting posteriorly the inferior poles of the medial rectus muscles to treat a V-pattern esotropia) has never been described. Slanting probably plays little or no role, he says, and that is why he does not advocate either slanting method.