Session Title: Free Paper Session 6: Vitreoretinal Surgery II
Session Date/Time: Thursday 07/09/2017 | 14:30-16:00
Paper Time: 15:00
Venue: Room 111
First Author: : J.de Jong NETHERLANDS
Co Author(s): : J. Vigueras-Guillen R. Timman K. Vermeer J. van Meurs
Traditionally, preoperative posturing consisting of bed rest and positioning is prescribed to patients with macula-on retinal detachment (RD) to prevent RD progression and detachment of the fovea. Despite the major burden of posturing to the patients and, when combined with hospital admission, to nursing staff, ward facilities and public health costs, little prospectively collected evidence for preoperative posturing has been presented as yet. This study aims to investigate in an ethically acceptable manner if preoperative posturing affects the progression of RD.
Single centre, prospective, comparative, non-randomized trial
We included 100 patients divided over 2 cohorts of 50 patients with macula-on RD located in the superior temporal quadrant of the retina. Other inclusion criteria were: volume OCT scans could be obtained with sufficient quality; smallest distance from the fovea to the detachment border ≥1.25 mm. Patients were admitted to the ward for bed rest in anticipation of their surgery and were positioned on the side where the RD was mainly located. At baseline and before and after each interruption for meals or toilet visits, a 37°x45° OCT volume scan was performed using a wide angle Spectralis OCT (Heidelberg Engineering, Germany). In the first cohort the usual duration of interruptions was followed, but in the second cohort the duration of interruptions was prolonged with sitting upright for 20 minutes. The distance between RD border and fovea was measured using a custom-built measuring tool. The distance measurements were also used to determine the rate of unacceptable progression, defined as 250 um from baseline. The RD border displacement moving towards (negative) or away (positive) from the fovea was determined for intervals of posturing and interruptions.
The median smallest distance between RD border and fovea at baseline was 4.9mm (range: 1.3-12.4 mm) in the first cohort and 3.5mm (range: 1.5-14.9 mm) in the second cohort (p=0.045, t-test). The median duration of intervals of posturing was 2.8 hours (inter quartile range (IQR): 1.7 – 13.2; N=109) in the first cohort and 3.9 hours (inter quartile range (IQR): 1.9 – 12.6 hours; N=115) in the second cohort. The median duration of interruptions was 0.37 hours (IQR: 0.22 – 0.49; N=108) in the first cohort and 0.68 hours (IQR: 0.55 – 0.79; N=103) in the second cohort. The median RD border displacement velocity for all 100 patients was +5µm/hour (IQR: -23 to +69; N=224) during posturing and -113µm/hour (IQR: -508 to +8; N=211) during interruptions which was significantly different (p<0.001, Mann Whitney U test). The median RD border displacement during interruptions was -74 µm (IQR: -182 to -7) in cohort 1 and -37 µm (IQR: -206 to +12) in cohort 2, which was not significantly different (p=0.516). Progression from baseline of more than 250 µm was found in 11 out of 50 (22%) patients in cohort 1 and in 12 out of 50 (24%) patients in cohort 2.
By making use of the interruptions of preoperative posturing and the precision and reach of a wide angle OCT on the ward we were able to show, in a prospective and ethically acceptable manner, that RD stabilizes during posturing and progresses during interruptions in patients with macula-on RD. Preoperative posturing is therefore effective in reducing progression of retinal detachment. Prolongation of posturing interruptions with sitting upright for 20 minutes does not significantly increase the risk of RD progression during these interruptions and also does not substantially increase the risk of unacceptable progression from baseline.