Commentary: Pneumoretinopexy versus scleral buckling in retinal detachments with superior breaks: A comparative analysis of outcome and cost.

The commonly used modalities for management of rhegmatogenous retinal detachments (RRD) are scleral buckling (SB), pars plana vitrectomy (PPV), pneumatic retinopexy (PnR) or a combination of the above techniques. Recent studies reported a primary retinal reattachment rate of more than 90% in uncomplicated RRD with both SB and PPV. The “scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment (SPR) study” showed that PPV had higher anatomical success rates in pseudophakic eyes, whereas SB had better visual improvement rates in phakic eyes.[1] However, both these techniques are invasive and surgically complex procedures. PnR on the other hand is a relatively simple procedure that was described for the first time by Hilton and Grizzard1 more than 30 years ago as a “two-step outpatient operation without conjunctival incision.”[2]

PnR is an office-based procedure designed for repairing selected retinal detachments. The mechanism of action of PnR is by the tamponade of retinal breaks with an intraocular gas bubble and induction of chorioretinal adhesion with cryopexy or laser.[3]

The basic criteria required for PnR include the following:-

1) Presence of a single or multiple retinal breaks occupying 1 clock hour of the retinal arc

2) location of all retinal breaks in the superior 8 clock hours of the globe (from 4 o clock to 8 o clock meridians)

3) ability of the patient to maintain the proper head position.

Patients with a retinal detachment not satisfying these criteria are expected to have much poorer responses to PnR than those that do adhere to the above-mentioned criteria. Apart from this, studies have shown a lower success rate of PnR in pseudophakic or aphakic eyes as compared to phakic eyes.[4]

The efficacy of PnR depends upon:-

1) induction of adequate retinopexy around the retinal breaks with cryopexy or laser

2) intraocular gas injection

3) consistent postoperative head positioning so that the gas tamponade can help in achieving closure of the retinal breaks.

Choices of the agent for intraocular tamponade include air, sulfur hexafluoride (SF6), perfluoroethane (C2F4), and perfluoropropane (C3F8). The preferable agent according to us is SF6 due to its ability to achieve a maximum size rapidly and because of its shorter duration before it dissipates.

Brinton and Hilton estimated that at least 40% of RRD can be managed by PnR[4] Hilton and Grizzard had originally reported a high success rate of 90% for PnR. Subsequent studies have demonstrated a success rate which has varied vary between 60 and 82%. A review of 81 studies of 4,138 eyes undergoing primary PnR revealed a single operation success rate of 74.4% in phakic and pseudophakic patients. Chan et al. had reported a primary success rate of a single PnR procedure in phakic patients to be between 71 and 84%. In pseudophakic patients, the primary reattachment rate was between 41 and 67%.[5]

The PIVOT trial (pneumoretinopexy vitrectomy outcome trial) reported enhanced vision gain of 4.9 letters in eyes subjected to PnR along with less vertical metamorphopsia and reduced morbidity when compared with primary PPV.[6]

The major advantages and benefits of PnR over SB and PPV consist of the performance of a relatively noninvasive and brief procedure in the office setting, bypassing numerous requirements and their associated expenses for surgery in the operating room.[678]

Apart from the economic benefits, this has other advantages in developing countries too since it may translate into a timely management of RRD in even in the absence of operating room infrastructure.