Why the PIMS trial
The macula is the central area at the back of the eye, necessary for seeing fine detail and for reading.
Sometimes a hole develops in the macula, a condition affecting eight in every 100,000 people. A surgical procedure known as a vitrectomy is the recommended treatment and involves injecting a gas bubble into the eye to press against the macula, helping the hole to seal. Since the surgery was first described around 25 years ago, patients have been advised to maintain a face-down position, known as posturing, for up to 10 days following surgery to help the gas bubble stay in place. However, there is little hard evidence to support the benefit or technique of posturing which has led to a wide variation in the advice given to patients, with some surgeons abandoning the practice altogether.
The lack of clarity regarding posturing prompted experts, including Professor James Bainbridge, Consultant Retinal Surgeon, Moorfields Eye Hospital, along with the Cochrane Eyes and Vision Group to conduct a Cochrane review - a systematic review of the existing evidence relating to posturing after macular hole surgery. Only three studies out of 266 met the rigorous standards required for inclusion. The review concluded that face-down posturing did not improve repair of small macular holes (<400µm); and while some improvement was seen in the repair of large holes (>400μm) these data were insufficient to draw firm conclusions thereby highlighting a need for more robust evidence to guide clinical practice. Posturing can be very difficult for patients, particularly as macular holes are more common in people aged over 75 years who are more likely to suffer with joint disorders such as arthritis making face-down posturing awkward or even painful. Moreover, it carries a small but serious risk that some people could experience nerve compression or a blood clot. In 2012, a national initiative called The James Lind Alliance Sight Loss and Vision Priority Setting Partnership identified that the public felt that research into methods to prevent and improve the treatment of macular hole were a priority for them - if patients are going to endure the discomfort and inconvenience of posturing, they want to be sure that it has proven benefit. To address these public and clinical priorities, Professor Bainbridge conducted a successful pilot study and is now running the PIMS (Positioning In Macular hole Surgery) trial, a large randomised controlled trial, to answer the question of whether posturing improves repair of larger macular holes. Patients have been instrumental in informing the design of this research. PPI in PIMS Retina Day 2015: The role of PPI in the PIMS trial
VIDEO Learning from personal experiences “Patient and public involvement, known as PPI, has long been a core element of our research. Patient insights are essential to ensure our research meets the needs of the people affected by eye conditions. We felt it was important to involve them in this trial from an early stage,” said Professor Bainbridge. “Patients from the pilot study were ideal candidates to advise on the larger trial, and they were invited to get involved from the very start, contributing to the initial funding application onwards.”
Five patients accepted the invitation and they’ve been integral to the research process ever since. One of the patient advisors, Roy Smith, explained,
“Having been through the treatment myself, I believe I have a duty to get involved in this research, to help improve things for future patients and to help move the science forward.” The patients initially attended an advisory board to provide their views on their condition and the value of the treatment and advice they received when they postured after macular hole surgery. They were then consulted about the trial design; and Roy now sits on the steering committee which meets regularly to monitor the trial’s progress. “The people on the research team listen and take on board our feedback, making us feel like valued and respected members of the team," said Roy. "Nowadays many patients go home on the same day as their surgery, so the medical team doesn’t see the recovery period. I think one of the most important contributions patients have made to this research is to increase understanding of the challenges and needs of patients during their recovery.” Mr. Saruban Pasu, Clinical Research Fellow and co-investigator of the PIMS trial said, “PPI is not widely understood and the successful patient involvement in this trial has provided a blueprint of how it can be implemented. Through our public information days the trial has served to widen awareness of PPI, catalysing engagement and participation amongst other patients.” Keeping the focus on patient needs “Patient and public involvement has helped to ensure our trial is relevant to, and meets the needs of, those affected by macular hole, which will ultimately make the results more translatable into the day-to-day realities of clinical practice and patients’ lives,” said Professor Bainbridge. “The patients have had a very important contribution towards the trial design,” said Mr. Pasu, “Multiple changes have been made to the design since the pilot study, as a result of their feedback.” The primary outcome measure was originally going to be long-term improvement in patients’ sight. This changed following patient consensus that anatomical closure of the macular hole was their highest priority, as this influenced whether they would need further corrective surgery. They also requested the inclusion of qualitative outcome measures and so a validated questionnaire will assess patients’ quality of life following surgery. Many adaptations related to posturing, one of which involved the term itself which patients felt was misleading. As a result, the term was changed to ‘positioning’. Roy explained, “We reviewed the information booklet that provides patients with guidance on positioning and felt that some of the images were confusing and more detail was required for clarity.” This resulted in separate information booklets for patients in the face-down and face-forward arms of the trial, with the inclusion of: - Guidance on clothing, eating and entertainment whilst positioning - Example schedules for the positioning regime - Explanatory pictures demonstrating face-down and face-forward positioning.
Guidance to maintain face-down positioning at night was removed as Roy recalled,
“It was very difficult to sleep with your head face down. Not only was it uncomfortable, but I tended to wake up in the night, invariably in a different position. As it’s just not feasible to stick to, we advised removing it.” The benefits of clarity on an age-old practice The results of the trial should finally prove whether or not postoperative face-down positioning impacts the success of surgical repair of large macular holes. This will inform evidence-based practice which could decrease health service costs through improved surgical outcomes. It will also provide patients with confidence when making decisions about their management in the future.
The PIMS (Positioning In Macular hole Surgery) trial aims to determine whether advice to position face-down, as opposed to face-forward, improves the surgical success rate of closure of large (≥400μm) macular holes, so reducing the need for further surgery.
The trial is funded by the NIHR Research for Patient Benefit and led by the NIHR Moorfields Biomedical Research Centre (BRC), a partnership between Moorfields Eye Hospital NHS Foundation Trust and the UCL Institute of Ophthalmology.
As one of only 11 national Biomedical Research Centres, the NIHR Moorfields BRC is the only one dedicated to eye conditions.
The PIMS trial is currently open and recruiting patients until April 2017. For more information about the trial please
Principal Investigator: Professor James Bainbridge MA PhD FRCOphth
Co-investigator: Mr. Saruban Pasu BSc MBBS FRCOphth