Positioning In Macular hole Surgery (PIMS): statistical analysis plan for a randomised controlled trial

Abstract

BackgroundThe treatment of idiopathic full-thickness macular holes involves surgery to close the hole. Some surgeons advise patients to adopt a face-down position to increase the likelihood of successful macular hole closure. However, patients often find the face-down positioning arduous. There is a lack of conclusive evidence that face-down positioning improves the outcome. The ‘Positioning In Macular hole Surgery’ (PIMS) trial will assess whether advice to position face-down after surgery improves the surgical success rate for the closure of large (≥400 μm) macular holes.Methods/designThe PIMS trial is a multicentre, parallel-group, superiority clinical trial with 1:1 randomisation. Patients (n = 192) with macular holes (≥400 μm) will be randomised after surgery to either face-down positioning or face-forward positioning for at least 8 h (which can be either consecutive or nonconsecutive) a day, for 5 days following surgery. Inclusion criteria are: presence of an idiopathic full-thickness macular hole ≥400 μm in diameter, as measured by optical coherence tomography (OCT) scans, on either or both eyes; patients electing to have surgery for a macular hole, with or without simultaneous phacoemulsification and intraocular lens implant; ability and willingness to position face-down or in an inactive face-forward position; a history of visual loss suggesting a macular hole of 12 months’ or less duration. The primary outcome is successful macular hole closure at 3 months post surgery. The treatment effect will be reported as an odds ratio with 95% confidence interval, adjusted for size of macular hole and phakic lens status at baseline. Secondary outcome measures at 3 months are: further surgery for macular holes performed or planned (of those with unsuccessful closure); patient-reported experience of positioning; whether patients report they would still have elected to have the operation given what they know at follow-up; best-corrected visual acuity (BCVA) measured using Snellen charts at a standard distance of 6 m; patient-reported health and quality of life assessed using the National Eye Institute Visual Function Questionnaire (VFQ-25).DiscussionThe PIMS trial is the first multicentre randomised control trial to investigate the value of face-down positioning following macular hole standardised surgery.Trial registrationInternational Standard Randomised Controlled Trials Number registry, ID: ISRCTN12410596. Registered on 11 February 2015.United Kingdom Clinical Research Network, ID: UKCRN17966. Registered on 26 November 2014.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-017-2020-6) contains supplementary material, which is available to authorized users.

Adherence to face-down and non-supine positioning after macular hole surgery

“…It was not surprising that patient adherence to NSP was better than that to FDP considering better patient compliance to NSP [6–8, 10–14, 16, 19, 21, 23–25, 29, 30, 35, 36]. Almost half of the patients in the FDP group failed to obtain a 100% adherence rate and therefore the hypothesis that the patients would completely comply was largely compromised.…”

“…However, FDP is inconvenient and not easily tolerated by many patients, and thus, the duration of continuing FDP has been debated for years [2–8, 10–25, 29, 32–35]. Modifications in FDP to enhance tolerability, such as shortening the duration [2, 5, 8, 11, 12, 15, 17, 18, 23, 31, 32] and alleviated positioning, which generally avoids supine or face-up positioning (non-supine positioning, NSP) [6–8, 10–14, 16, 19, 21, 23–25, 29, 30, 34, 35] have previously been proposed. Prognoses observed after these modifications were statistically compared with those observed after strict adherence to FDP [5, 7, 8, 10–12, 22–25, 30].…”

Adherence to the face-down positioning after vitrectomy and gas tamponade: a time series analysis

“…In the treatment of MH, the optimal manner and duration of FDP to optimize patient recovery have been debated [ 2 , 4 – 33 ]. Although each protocol assumes that the patients will follow the given advice, some patients are noncompliant and may negatively impact the effectiveness of the surgery by being the sources of negative outcomes [ 35 ].…”

“…Face-down positioning (FDP) is recommended after vitrectomy and gas tamponade for rhegmatogenous retinal detachments (RRDs) [ 1 , 2 ] or for macular hole (MH) surgery [ 1 – 33 ]. But FDP is inconvenient and not readily tolerated; thus, the optimal method and duration of FDP have been debated for many years, especially after MH surgery [ 2 , 4 – 33 ].…”

“…Face-down positioning (FDP) is recommended after vitrectomy and gas tamponade for rhegmatogenous retinal detachments (RRDs) [ 1 , 2 ] or for macular hole (MH) surgery [ 1 – 33 ]. But FDP is inconvenient and not readily tolerated; thus, the optimal method and duration of FDP have been debated for many years, especially after MH surgery [ 2 , 4 – 33 ]. Shortening the duration of FDP [ 2 , 4 , 7 , 10 , 12 , 13 , 16 , 18 , 19 , 23 , 30 ] and the use of alternate positions, such as avoidance of the supine or face-up positions [ 8 – 15 , 17 , 20 , 21 , 23 – 26 , 29 , 32 , 33 ], has been proposed after comparisons with strict FDP [ 7 , 9 – 14 , 22 – 26 , 29 , 33 ].…”