View 1: Minimal segmental buckling without drainage

Scleral buckling involves either an encircling buckle, called cerclage, extending over the entire periphery of the retina with drainage of subretinal fluid or, as refinement, a segmental buckle (elastic sponge) extending over the area of the retinal break(s) and performed without drainage. The latter surgery is called “minimal segmental buckling” (MSB) and represents an extraocular technique for the repair of rhegmatogenous retinal detachments.¹ The elasticity of the sponge buckle makes it possible to eliminate drainage of subretinal fluid. The buckle and coagulation therapy, either cryopexy or laser, are limited to the area of the break(s). Consequently, it is of utmost importance to identify the break(s) and to position the buckle in the correct location. A further refinement of MSB is the balloon procedure, in which the segmental buckle is a temporary balloon which is not sutured onto the sclera and is withdrawn after a week. A Medline search identified 1462 primary retinal detachments treated with MSB without drainage. The buckle consisted of either segmental sponges (n = 962 detachments)^1–6 or a temporary balloon (n = 500 detachments)⁷ with coagulation therapy limited to the area of the break(s).

PROVED ADVANTAGES OF PRIMARY MINIMAL SEGMENTAL BUCKLING WITHOUT DRAINAGE

The procedure is undertaken under local or topical anaesthesia with inexpensive equipment and few trained additional personnel are required. It can be performed in an outpatient setting and on a low budget. The operating time is rarely more than 45 minutes and is 15–25 minutes with the balloon providing the break(s) are identified before surgery.

After treatment of 1462 detachments with MSB without drainage, the primary attachment rate was 91%. The low rate of further surgery (10.7% had one further procedure and 0.7% had two) favour MSB. Despite the presence of preoperative proliferative vitreoretinopathy (PVR) grade C₁–C₂ in 2.9%, the final attachment rate was 97% with a 2–15 year follow up. Among causes of final failure are: PVR, 1.9% and missed breaks, 0.8% (Table 1). There are no intraocular complications (except for a rare choroidal in 0.3%) because drainage is eliminated. Secondary glaucoma, cataract, intraocular haemorrhage, intraocular infection, incarceration of retina or vitreous, or iatrogenic tears do not occur because the procedure is extraocular. No postoperative positioning of the patient is required and travelling by aeroplane is not restricted because no gas is injected into the eye. There are no secondary operations in the anterior segment of the eye—for example, phacoemulsification due to a cataract with implantation of an intraocular lens, secondary glaucoma, etc, or in the posterior segment—for example, removal of silicone oil, etc.

Table 1 .

Attachment after minimal segmental buckling without drainage of 1462 primary retinal detachments

				Cause of final failure
Series	Detachments	Preoperative PVR* C1–C2	Primary attachment	Final attachment	PVR C1-C2	Missed break	Mean visual acuity	Follow up
1st2,3	752	5 (0.7%)	672 (89%)	732 (97%)	14 (1.9%)	4 (0.5%)	Not available	2 years
2nd1,4	107	16 (15%)	99 (93%)	99 (93%)	4 (3.7%)	3 (2.8%)	0.6†, 0.5‡	15 years
3rd5	35	6 (17%)	35 (100%)	35 (100%)	–	–	0.6	2 years
4th6	68	11 (16%)	65 (96%)	60 (88%)	8 (11.8%)	–	0.3	2 years
5th7§	500	5 (1%)	454 (91%)	493 (99%)	2 (0.4%)	5 (1%)	0.7	>2 years
Total	1462	43 (2.9%)	1325 (91%)	1419 (97%)	28 (1.9%)	12 (0.8%)		2–15 years

*PVR = proliferative vitreoretinopathy.

†After 2 years.

‡After 15 years.

§Treated with temporary balloon buckle without drainage.

After MSB without drainage, the recovery of visual function is optimal. In a series of 107 detachments (mean preoperative visual acuity 0.3) followed for visual acuity, the mean value was 0.6 at 1 year and 0.5 at 15 years.⁴ The observed slight decrease over years is the result of ageing, as confirmed by Slataper after an analysis of 17 349 individuals.⁸ Induced changes in refractive error after MSB are minor and do not occur after a temporary balloon buckle.

Therefore, the main advantage of MSB is that it reduces intraoperative and postoperative complications and yields optimal anatomical and functional results over a 2–15 year follow up. All of these factors are of benefit to the elderly patient and the financial resources. This is relevant because the new treatments for macular and retinal diseases are costly.

PRESUMED ADVANTAGES OF PRIMARY MINIMAL SEGMENTAL BUCKLING WITHOUT DRAINAGE

The minimum of surgical trauma inflicted results in a preservation of the blood-aqueous barrier, because MSB is performed without drainage of subretinal fluid and therefore without decompression of the eye or the injection into the eye to restore intraocular volume. For the surgery itself, no costly disposable instruments or expensive intraocular tamponades are required—for example, heavy perfluorocarbon liquids, expanding gases, or silicone oil—or subsequent surgical removal of the tamponades. Postoperatively, there is a rapid recovery of visual acuity that will not be jeopardised by secondary complications, so no secondary operations are needed.

DISADVANTAGES OF PRIMARY MINIMAL SEGMENTAL BUCKLING WITHOUT DRAINAGE

Preparation for MSB without drainage, in which the buckle and coagulation are limited to the break, may require extensive preoperative study of the detachment. Detecting breaks preoperatively is less costly, however, as the search uses the time of the surgeon and not the time of additional personnel in attendance in an expensively equipped operating room. Exposure or infection of the sponge buckle can occur, but is less than 0.5%. If a radial sponge is placed in the area of a rectus muscle, diplopia may occur, but can be eliminated with the use of a temporary balloon instead for breaks located beneath a rectus muscle. A prerequisite for MSB without drainage is experience in indirect ophthalmoscopy and microscopy to find all of the breaks and to tamponade them adequately, preferably by a radial buckle. Useful guidelines and indirect wide field contact lenses will help the microscopic search for small breaks in a pseudophakic eye.^9–12 In the analysed series of 1462 primary retinal detachments, multiple breaks and breaks of various size and constellations were included (excluded were tears >2 clock hours in extent and breaks at the posterior pole). With experience in MSB without drainage, reattachment after 1 procedure can be obtained in 91% and after reoperation in 97%.

The concept of MSB without drainage can be difficult to accept, because the retina does not become attached at the operating table. The surgeon must wait 24 hours or more for the retina to attach spontaneously. However, after spontaneous retinal attachment following MSB without drainage, the rate of redetachment over a 2 year period will be as low as 1.4% (series 1–4 = 962 retinal detachments) and after a balloon operation without drainage even as low as 0.8% (series 5 = 500 retinal detachments).

CONTROVERSY

In recent publications, primary vitrectomy has been compared with the results obtained with scleral buckling. However, the authors chose to compare a form of buckling that consisted of a cerclage with additional buckles, extensive coagulation therapy, drainage of subretinal fluid, and often with an intraocular gas or silicone oil tamponade. With that comparison it was concluded that scleral buckling has a higher morbidity than primary vitrectomy.^13–15 Had they compared primary vitrectomy with MSB without drainage, they would have concluded that segmental buckling has less morbidity than primary vitrectomy.^{1,2,4,5,6,7,16} This is the case even though an analysis of 595 detachments treated with vitrectomy, performed by experts,¹⁷ found that the rate of reoperation is 24.5% and PVR 11.5% in contrast with MSB, with a rate of reoperation of 10.7% and PVR of 1.9%.