It has been 25 years since Hilton and Grizzard1 in the United States and Dominguez2 in Spain introduced pneumatic retinopexy. Although the technique and indications for the procedure have changed in the intervening years, pneumatic retinopexy persists as a cost-effective non-incisional alternative to surgical procedures that provides superior visual outcomes after retinal detachment (RD).

In honor of the 25th anniversary of pneumatic retinopexy's birth, this article reviews some of what we know about this office-based procedure, its efficacy, and its cost-effectiveness compared with more invasive alternatives.

BACKGROUND
Pneumatic retinopexy is a non-incisional procedure for reattaching the retina by injecting an expanding gas bubble and applying laser and/or cryopexy. The operation as originally described was done in one session. Cryopexy was applied to the retinal break or breaks, the gas bubble was injected, and a paracentesis was sometimes performed.

With experience, the technique has evolved into a staged operation.3 First, if the detachment is not extensive, scatter photocoagulation is applied to attached retina between the posterior insertion of the vitreous base and the ora serrata using laser indirect ophthalmoscope. Care is taken to leave a 1-clock-hour margin between the border of the detached retina and the laser spots. This is done to avoid potentially creating breaks if the gas bubble displaces subretinal fluid beneath fresh laser applications. Cryopexy may then be applied to detached retinal breaks if they are not highly elevated. Following this, a paracentesis is performed (usually 0.25 mL can be removed) using a No. 27 or 30 needle on a plungerless 1 mL syringe, and 0.5 cc of SF6 gas is injected through the pars plana, away from any large breaks (Figure 1).

After this first stage, the patient is instructed to maintain a position so that the bubble is opposed to the break for 24 to 48 hours. Careful preoperative instruction is given to ensure that the patient understands the importance of correct positioning. A visual aid, the Tornambe Pneumo Level, a circular level marked with clock hours (Escalon/Trek Medical, New Berlin, WI), is attached to the patient's eye patch, and patient and family are shown how to achieve the desired position (Figure 2).

In the second phase 1 to 3 days later, scatter laser photocoagulation is completed around 360° of the peripheral retina (Figure 3). The positioning is then continued for an additional 3 to 5 days, 16 hours a day. The patient is instructed to limit activity, including reading, until the bubble resorbs.

The application of 360° of laser photocoagulation between the insertion of the vitreous base and the ora serrata improves the single-operation success rate by 5 to 10% and is vital for the success of pneumatic retinopexy. With use of this technique, the expected single-operation success rate approaches 97% (Figure 4).

SELECTION CRITERIA
Case selection for pneumatic retinopexy has evolved over time. The original inclusion criteria of Hilton and Grizzard,1 used in the randomized, prospective Pneumatic Retinopexy Clinical Trial,4,5 included eyes with retinal detachments not associated with PVR, clear media, and one or more breaks not larger than 1 clock hour. Tears were located in the upper two-thirds of the fundus. Eyes could have lattice degeneration not exceeding 3 clock hours, pseudophakia, and retinal detachment of any size. The amount of subretinal fluid was not a consideration, but the detachment had to extend at least three disc diameters from the break or breaks.

The success of pneumatic retinopexy depends on proper patient selection as well as surgical technique. In a review of 302 consecutive cases of pneumatic retinopexy by a single surgeon,3 prognostic indicators were identified. Favorable selection criteria included phakic eyes, less extensive retinal detachment, detachment secondary to a superior retinal break less than 1 clock hour in size, and no proliferative vitreoretinopathy (PVR). Negative prognostic indicators include hazy vitreous, inferior retinal breaks, many breaks, extensive lattice degeneration, extensive blood, and star folds exerting traction on the break or breaks.

More complex detachments can be repaired with pneumatic retinopexy, but with inclusion of these cases the single-operation success rate decreases. Factors negatively influencing single-operation anatomic success include pseudophakia, a greater number of retinal breaks, and a greater area of detached retina. Factors not found to influence outcome include the presence of lattice degeneration of less than 3 clock hours, the type of retinal break, the type or volume of gas used, the type of retinopexy used (laser or cryotherapy), the sequence of gas insertion vs retinopexy application, the status of the posterior capsule, and the patient's sex.

In deciding whether to perform pneumatic retinopexy, the surgeon must have time to thoroughly examine the retina before the procedure, adequate experience not to perform excessive cryopexy, a commitment to examine the patient frequently postoperatively, and the ability to operate within a few days if the procedure fails. The patient is not a good candidate if he or she is unable to be examined, does not have the mental ability to understand the operation, is physically unable to achieve the post-procedure positioning, cannot make the follow-up appointments, or must fly within 1 week.

Eyes that should not have pneumatic retinopexy include those whose fellow eye had a bad outcome from pneumatic retinopexy or had a giant tear, and those in which the media prevent a detailed retinal examination (cataract, capsular clouding, vitreous hemorrhage, small pupil). Pseudophakia is not a contraindication.

DEFINITION OF SUCCESS
Single-operation success with pneumatic retinopexy is desirable because these eyes achieve the best visual acuity outcomes. However, it must be emphasized that the objective of retinal detachment surgery is not to reattach the retina; it is to restore pre-detachment vision, regardless of the single-operation success rate. In my experience, eyes successfully treated with pneumatic retinopexy attain the best post-detachment vision, which is why I advocate the procedure.

If a pneumatic retinopexy is done properly and fails, and a prompt rescue operation is performed, the eye is not disadvantaged by the pneumatic procedure. A failed pneumatic procedure does not unfavorably affect visual outcome when compared with scleral buckling.6,7 In other words, there is no downside in trying pneumatic retinopexy first in eyes that meet the selection criteria. Eyes may be prone to develop PVR if excessive cryo is used to treat a very elevated break and the rescue operation is not performed within a few days.

In my practice, overall, approximately seven of 10 patients who present with retinal detachment are first treated with pneumatic retinopexy. Of these, one or two fail. Thus more than half of all patients with retinal detachment can be successfully treated with pneumatic retinopexy and never go to the operating room.

ECONOMIC IMPLICATIONS
The economic implications of treating more than 50% of all retinal detachments outside the operating room are enormous. Of course, not only is the office-based procedure less expensive than incisional procedures, but also there are additional potential savings if the number of reoperations is reduced through careful patient selection and use of proper technique.

In an economic analysis of data from the Pneumatic Retinopexy Clinical Trial,3 I found that treating a group of eyes with pneumatic retinopexy first cut almost in half the cost of treating that same group with scleral buckling first, including reoperations. With ideal patient selection and optimal surgical technique, pneumatic retinopexy first was approximately one-fourth the cost of scleral buckling first. These calculations assumed that pneumatic retinopexy, laser, and cryopexy are done in an office setting and all incisional procedures are done in an ambulatory surgery center.

Unfortunately, there are currently economic disincentives to performing pneumatic retinopexy. Recently, reimbursement for pneumatic retinopexy was reduced by almost half through bundling of the gas injection with the retinopexy treatment. The surgeon is now paid significantly more for scleral buckling and vitrectomy than for pneumatic retinopexy. This will undoubtedly encourage some surgeons to revert back to OR-based retinal surgery, which, overall, will cost the health care system significantly more than the reduction achieved by decreasing the surgeon's fee for pneumatic retinopexy. It must be said that this was a very “penny wise but pound foolish” decision that we must hope will be addressed in future reimbursement adjustments.

CONCLUSIONS
Single-operation success with pneumatic retinopexy is desirable because it is associated with the best visual acuity results. However, a failed pneumatic retinopexy does not unfavorably affect visual outcome when compared with scleral buckling. With careful case selection and proper surgical technique, eyes treated with pneumatic retinopexy enjoy a high rate of anatomic and visual success. In addition, pneumatic retinopexy may be the most cost-effective means to repair a retinal detachment. With careful patient selection and 360° retinopexy, pneumatic retinopexy may reduce costs by up to 75% compared with scleral buckling.

Paul E. Tornambe, MD, is in private practice at Retina Consultants San Diego and is an instructor in the departments of ophthalmology and family practice at the University of California, San Diego. Dr. Tornambe states that he has no proprietary interests in products discussed in this article. He can be reached at 858-451-1911; or via e-mail at TornambePE@aol.com.

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