Vitrectomy beats scleral buckling in rhegmatogenous retinal detachment study

June 7, 2017

Eyes operated on with pars plana vitrectomy needed fewer reoperations over 180 days than eyes subjected to scleral buckling (SB) in a retrospective comparison of patients with rhegmatogenous retinal detachment (RRD).

Eyes operated on with pars plana vitrectomy needed fewer reoperations over 180 days than eyes subjected to scleral buckling (SB) in a retrospective comparison of patients with rhegmatogenous retinal detachment (RRD).

“The reasons for inferiority of SB procedure in our study could be related to various patient-, eye-, and/or surgical technique-related characteristics,” wrote Dr Sari Sahanne from Helsinki University Central Hospital, Helsinki, Finland and colleagues. They published the findings in Clinical Ophthalmology.

SB and vitrectomy are the most common procedures for repair of RRD and previous studies have shown that they succeed around 85% to 91% of the time.

Currently, SB is considered the first choice for phakic primary RRD and pars plana vitrectormy is considered the first choice for pseudophakic RRD.

Study design

To compare the success rates of the two procedures, Dr Sahanne and colleagues analysed records of 319 patients admitted for RRD in one eye each at Helsinki University Hospital. They did not include eyes that underwent both procedures.

Fifty of these patients (15.7%) underwent SB and the rest (84.3%) pars plana vitrectomy. The two groups differed in some key characteristics. The mean age of presentation was 54.3 years in the SB group and 61.4 in the vitrectomy group.

The retinal detachment patients in the SB group were healthier. Among men, more received SB than vitrectomy.

Also, 19.3% of patients in the vitrectomy group had detachments larger than two quadrants, compared with 2% of patients in the SB group.

Preoperatively, IOP was lower and occurrence of vitreous haemorrhage was more common in eyes operated with vitrectomy.

The patients who underwent SB had conjunctival peritomy, isolation and looping of rectus muscles, external marking of holes and breaks via diathermy.

The treatment of retinal holes or breaks in these patients consisted of cryoretinopexy (ca. -80°C) via indirect ophthalmoscopy and suturing of segmental circumferential silicone buckles (with a foam sponge sutured to the sclera) to support the retinal holes or breaks. Some had external drainage of subretinal fluid.

Following conjunctival closure, these patients received paraocular gensumycin and kenalog injections.

Pars plana vitrectomy was valved and transconjunctival (20-, 23- or 25-gauge). Surgeons used three-dimensional vitrectomy mode with cutting rates of up to 5,000 per minute and suction up to 500 mm Hg. They reattached the retina with perfluorocarbon liquids. They performed chromodissection with a combination of brilliant blue and trypan blue (0.15%) for epiretinal proliferative vitreoretinopathy membrane and internal limiting membrane staining.

The surgeons used dissection techniques to remove preretinal membranes lying on the internal limiting membrane. Occasionally they used triamcinolone acetonide to visualise the peripheral vitreous. They drained subretinal fluid through either a pre-existing original retinal break or a posterior drainage retinotomy in eyes with anterior retinal breaks.

They also performed fluid air exchange with flute needle suction. They chose among tamponade gas, sulphur hexafluoride, perfluoroethane or perfluoropropane, and silicone oil as tamponades depending on the location and characteristics of the retinal detachment and the expected patient adherence.

After the gas exchange, the surgeons performed sclerotomy massage to promote self healing. If they suspected sclerotomy, they fixed sutures. Postoperatively, the patients received dexamethasone (1 mg/mL) or chloramphenicol (2 mg/mL) eye drops four times a day for four weeks.

Increased IOP

 

Increased IOP

After 30 days, mean IOP increased 4.4 mm Hg in the SB group and 8.1 mm Hg in the vitrectomy group, which was statistically significant (p = 0.006). Best-corrected visual acuity decreased by 0.11 logMAR in the scleral buckle group and 0.17 logMAR in the vitrectomy group.

The success rate without reoperation within 180 days was 78% for SB and 91.8% for vitrectomy, a statistically significant difference (p = 0.001).

“The fact that primary SB procedures more often had a need for reoperation is of importance,” Dr Sahanne and colleagues wrote.

They speculated that the cryotherapy used in scleral buckling could account for the difference in reoperation rates. It could increase growth factors, extracelluar matrix proteolytic factors and other factors contributing to the breakdown of the blood-retinal barrier and leading to proliferative vitreoretinopathy.

During microincisional valved pars plana vitrectomy, surgeons can remove more retinal pigment epithelial cells along with the irregular and rolled edges of the retinal edges, decreasing the factors that might cause proliferative vitreoretinopathy.

Cryotherapy could also induce more inflammation and contraction, the authors noted.

And they pointed out that the loss of vitreous during external drainage of subretinal fluid and incarceration of vitreous to the external drainage sclerotomy during SB could cause additional traction and open additional holes or breaks.

Undetected retinal holes might play a role in the higher redetachment rate in SB as well, they wrote.

But they concluded with a reminder that surgeons should consider the advantages and disadvantages of the two procedures on a case-by-case basis.