Rectus muscle pseudo-adherence syndrome

Abstract

Purpose: To describe a clinical entity called "rectus muscle pseudo-adherence syndrome" following buckling surgery.

Methods: A retrospective data review was undertaken to analyze the clinical profile of strabismus patients who had developed it following buckling surgery. Between 2017 and 2021, a total of 14 patients were identified. The demography, surgical details, and intraoperative challenges were reviewed.

Results: The average age of the 14 patients was 21.71 ± 5.23 years. The mean pre-op deviation was 42.35 ± 14.35 prism diopters (PD) of exotropia, and the mean post-op deviation was 8.25 ± 4.88 PD of residual exotropia at 26.16 ± 19.53 months follow-up. Intraoperatively, in the absence of a buckle, the thinned-out rectus adhered to the underlying sclera with much denser adhesions along its margins. When there was a buckle, the rectus muscle adhered to the outer surface of the buckle again, but less densely, with marginal union into the surrounding tenons. In both scenarios, due to the absence of protective muscle coverings, the rectus muscles were naturally adsorbed onto the immediately available surface in the presence of active healing by the tenons.

Conclusion: While correcting ocular deviations following buckling surgery, a false sense of an absent, slipped, or thinned-out rectus muscle is very much possible. This is due to active healing of the muscle with the surrounding sclera or the buckle in a single layer of tenons. This is the rectus muscle pseudo-adherence syndrome, where the culprit is the healing process and not the muscle.

Keywords: Buckling surgery; pseudo-adherence; rectus muscle.

Figure 1

In a case with explanted buckle and hypertropia, the superior rectus exploration shows a densely adherent muscle (a, blue arrow). It is greatly thinned out with completely lost muscle bulk. It has firm union with the sclera with no clear space to hook or grasp. The margins are even more thin with dense adhesions. This is due to active healing of muscle and the sclera in a single layer of tenons (in the absence of muscle inhibitory layers like capsule and others). (a and b, blue arrows). Under such circumstances, firstly, the ciliary vessels are traced along the muscle insertion (b, blue arrows), after which under a high-magnification microscope, the tendinous fibers are visualized to confirm the muscle, including its width, thickness, and extent (b, blue arrows). At the intended margins on one side, an opening is made in the fibrous tenons capsule (c-e, blue arrow). Once it is accessed, the thin muscle is gently hooked and its underneath adhesions are dissected by sweeping the scissors (f, blue arrow). This is repeated in the opposite side (g, h, blue arrows) and the whole width of the muscle is secured (i). In this muscle, the required amount of recession surgery is performed and the surgery is completed

Figure 2

In a patient with buckle in situ, the engulfment of muscle over its surface by the tenons can be seen (a). Stepwise approach consisting of three steps, an opening is made at its easily visible side (b, green arrow). On the other side, it looks more difficult, but again with detailed assessment, an opening is made at the right point (c and d, green arrows). After this, the underneath adhesions with the buckle surface are dissected out and the muscle is secured completely. The intended level of recession is performed and the surgery is completed (e and f)

Figure 3

The animated diagram shows the densely adherent muscle with engulfed margins (a). After opening the fibrous tenons on either side, the total muscle width is secured with clear margins (b)