This was a prospective interventional case series conducted at Farabi Eye Hospital, Tehran University of Medical Sciences, a tertiary ophthalmology center in Iran. The study protocol was approved by the Institutional Review Board of the Farabi Eye Hospital and the study adhered to the Declaration of Helsinki. Eligible patients participated after providing written informed consent.
Patients with RRDs amenable to SB seen between May 1, 2017 to January 1, 2018 were included. A detailed history was taken from all patients who also received a complete ophthalmic examination preoperatively including best-corrected visual acuity (BCVA), intraocular pressure measurements, slit-lamp examination, and dilated fundus examinations. Snellen acuity taken in the clinic was converted into logarithm of the minimum angle of resolution (logMAR) for the purpose of statistical analysis. Special attention was placed on the status of the retina [macular status, presence of proliferative vitreoretinopathy (PVR), clock-hours detached, and number/location of breaks] and any possible media opacities including the lens status.
Retinal detachment in eyes with pathologies such as break or lattice degeneration in more than two quadrants which were not suitable to be managed by segmental sponge or pneumatic retinopexy, including those with either localized detachments or total retinal detachments, were included. Eyes were excluded from this study if there was poor visualization of the retina from any causes (e.g., cataract, vitreous hemorrhage, corneal opacity), giant retinal tears, posterior retinal breaks not amenable to buckling, no breaks visualized, previously failed primary SB or pneumatic retinopexy, grade C PVR or worse, or any prior history of ocular disease that would affect vision including amblyopia, macular degeneration, optic neuropathy, retinal vascular occlusion, or vision-threatening forms of diabetic retinopathy.
Patients were randomly assigned to one of two intervention arms using a numerical random generator. Group S received standard SB with cryopexy of retinal breaks, whereas group M received a modified surgical approach. All the surgeries were performed by second-year vitreoretinal surgery fellows as a part of their fellowship training program under supervision of an expert surgeon (H.K.).
Primary outcome measures were operative time, anatomic success (single surgery successful retinal reattachment) at month 12, and BCVA at month 12. Secondary outcome was complication rate during the follow-up period. The time of the surgery recorded for each patient was defined as the time between the start of the conjunctival peritomy to the placement of the last conjunctival suture.
Overview of Current Procedure (Group S)
After the eye was prepped and draped in the standard ophthalmic manner, a 360° conjunctival peritomy was performed, followed by isolation of the four rectus muscles with silk suture. The external globe was examined for scleral thinning and abnormal vortex veins. A complete 360° scleral depressed examination was done with marking of the retinal breaks and cryopexy of the breaks. Then two mattress sutures with 5.0 MERSILENE® were pre-placed in each quadrant. In quadrants with a tire, the anterior suture pass was usually made at the level of muscle insertion with possible location adjustment to provide support to visualized breaks. The posterior suture pass was made 10 mm posterior to the anterior suture pass. In quadrants with only a band, the anterior and posterior suture passes were made approximately 12 and 16 mm posterior to the limbus, respectively. The placement of the buckle was done such that the break would ideally fall on the posterior 1/3 of the buckle.
An encircling silicone tire (276/279, Mira Inc., Uxbridge, MA, USA) was placed in the quadrants of the causative break and peripheral pathologies such as lattice degeneration (usually not 360°) as well as under the corresponding rectus muscle and the pre-placed non-absorbable sutures. A 240-silicone encircling band was placed through the groove of the tire and circumferentially 360° (under the rectus muscles and pre-placed sutures). If needed subretinal fluid drainage was performed, preferably at a site beneath the buckle. The tire and band were secured to the sclera by tying the pre-placed sutures. Then two ends of the band were passed through a loop of releasable 5.0 non-absorbable suture. Indirect ophthalmoscopy was done to confirm appropriate support of the break with adjustment of the buckle until it achieved the desired height after which the loop of suture was tightened. The excess ends of the band were cut 2–3 mm away from the suture. The conjunctiva was closed with 5.0 polyglactin 910 (Vicryl®) suture.
Modification of Procedure (Group M)
After isolation of the muscles with silk suture and external inspection of the globe, a single mattress suture with 5.0 non-absorbable suture was placed in the center of each quadrant without localization of the causative breaks, except for the final quadrant in which the two mattress sutures were placed to secure the ends of SB (Fig. 1). In quadrants that would have a tire, the anterior pass was made at the level of the muscle insertion and the posterior pass 10 mm away, while in quadrants with only a band the sutures were placed as previously described in group S. Then the silicone tire (276/279) and 240 band were passed under the rectus muscles and pre-placed sutures which were tightened to secure the buckle. The tire was placed in quadrants with corresponding retinal detachments and peripheral pathologies that were seen in clinic while the 240 band was circumferentially 360°. Similar to the standard technique, the two free ends of the buckle met in the final quadrant and were passed through a loop of releasable non-absorbable suture. Then, 0.1 ml of aqueous humor was removed and the buckle was tightened up to the point where the intraocular pressure normalized on tactile inspection at which point the loop of releasable suture was tightened. Excess buckle length was then cut 2–3 mm away from the non-absorbable suture. No cryopexy or subretinal fluid drainage was performed during the procedure. The retina was visualized only at the end of the surgery with indirect ophthalmoscopy to ensure patency of the central retinal artery.
The schematics of standard and modified SB approaches are shown in Fig. 2a and b, respectively.
Patients were treated with chloramphenicol eyedrops every 6 h for 1 week and betamethasone 1.0% every 4 h for 1 week, after which the dose was tapered during 3 weeks. Patients were followed postoperatively for at least 12 months. Data collectors were masked as to each patient’s surgical arm. During the follow-up period, any new or previously undiagnosed posterior breaks were treated with barrier laser.
Mean, standard deviation, range, frequency, and percentage were used to describe data. Chi-square, Fisher exact, Mann–Whitney, and t tests were used to compare differences between groups. Analysis of covariance (ANCOVA) was used to determine any significant differences in adjusted means. To assess the predictive effect of possible dependent variables on postoperative BCVA, a non-parametric regression model was tested. Statistical analysis was performed using SPSS software (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp.). P values of 0.05 or less were considered statistically significant.