Introduction

Pneumatic retinopexy (PR) was introduced by Hilton and Grizzard in 1986 as an outpatient procedure to repair rhegmatogenous retinal detachments.^[1] It supplemented the preexisting operative procedures used to repair rhegmatogenous detachments including scleral buckling and pars plana vitrectomy. It is an effective, less-invasive method of retinal detachment repair in selected cases.^{[2] [3]}

While scleral buckling and pars plana vitrectomy are other management options for retinal detachments, PR offers several potential advantages; it is less invasive, can be performed in-office, avoids post-operative refractive shift or strabismus, and is associated with a faster recovery. The most important factor in optimizing a successful outcome is proper patient selection. 

The article below focuses mainly on the technical aspects of the procedure. Note that these are general guidelines, but that others have reported success in situations beyond these listed. For example, the randomized study by Hillier, et al. included patients with breaks within attached retina in the inferior quadrant and still had good success rates; the appropriateness of every case should be determined by the individual patient and his/her surgeon.

Indications

• Retinal break(s) located in the superior 2/3 of the fundus (from 8 to 4 o’clock)
• Single or multiple breaks within 1 clock hour
• No break in the inferior 4 clock hours
• Minimal media opacity
• No PVR grade B or worse
• No glaucoma history
• Patient able to maintain positioning for 5-8 days after procedure

Relative Contraindications

• Pseudophakia or aphakia
• Up to grade A or B proliferative vitreo-retinopathy (PVR)
• Retinal breaks up to 3 clock hours apart
• Up to 3 clock hours of lattice degeneration^[4]
• Detachment of 2 or more retinal quadrants

Contraindications

• Breaks within the inferior 4 clock hours, especially if associated with detached retina
• Grade C or D PVR
• Extensive lattice degeneration or traction
• Excessive vitreoretinal adhesions
• Significant media opacity
• Severe glaucoma
• Patient unable to maintain postoperative positioning
• Patient must fly or travel to altitude soon after surgery

Advantages

• Outpatient procedure
• Less discomfort than operating room procedures
• No need for MAC or general anesthesia
• No change in refractive error
• No diplopia
• Lower risk of infection
• Faster ocular and systemic recovery
• Lower cost procedure
• Patient can still have operating room procedure without affecting visual prognosis or may have improved prognosis (PIVOT)

Disadvantages

Single-operation success rate is lower than operating room procedures. One survey of the literature revealed a cumulative initial success rate of 75.5%, with a final success rate of 97.4%, as opposed to the initial success rates of pars plana vitrectomy and scleral buckling which are in the 85-88% range.^[5] Failure of pneumatic retinopexy is thought to be due to reopening of one of the original breaks, or to missed or new tears. Studies have generally reported higher success rates for pneumatic retinopexy in phakic eyes, likely due to missed or new tears in pseudophakes and aphakes.

• Requires a surgeon highly skilled at retinal examination
• Not all detachments are amenable to repair with pneumatic retinopexy
• Requires significant patient cooperation and positioning
• Surgeon must be able to manage postoperative care and complications

Surgical Procedure

Instrumentation & Medication

• Sterile Gloves
• Betadine solution (5% and 10%)
• Xylocaine 1%/Marcaine 0.5%
• 2% Lidocaine
• Antibiotic/steroid ointment
• Lid speculum
• Conjunctival forceps
• Cotton-tipped applicators
• Two tuberculin syringes with two 27g 1/2-inch needles
• Laser or Cryotherapy unit
• Intraocular gas (SF₆ or C₃F₈)
• Millipore filter
• Indirect ophthalmoscope

Gas Selection

• The shortest-acting gas that is thought to be adequate should be chosen. SF₆ or C₃F₈ are the most common intraocular gases utilized in the United States; remember that these are generally used in their pure (100% concentration) form in PR whereas they are diluted when used in vitrectomy surgery.
• Pure SF₆ lasts approximately 2 -3 weeks and expands 2-fold within two days
• Pure C₃F₈ lasts approximately 6-8 weeks and expands 4-fold within four days

Operative Procedure

1. Retinal re-examination with confirmation of all areas of pathology.
2. Local anesthesia administered for patient comfort. Use 2% lidocaine subconjunctival injection, or give a retrobulbar block if needed (but this would impair patient's ability to cooperate by moving their eyes in the direction needed to treat the retinal tears).
3. Trans scleral cryotherapy is applied to the retinal tears in detached retina. Highly elevated breaks may be flattened by a steamroller maneuver. Care should be taken to avoid excess cryotherapy to prevent possible release of RPE cells and subsequent PVR formation.^[6] Laser photocoagulation can be used in attached areas of retina. Pseudophakic and high risk eyes may benefit from 360-degree laser. Alternative option is to do a staged procedure: (1) Inject gas, have patient position with bubble on the tear to flatten the retina (2) perform laser to the retinal tear a few days after the retina is flat. Note: Make sure to have a detailed preop drawing so you know where the retinal tear is located, as this can be difficult to see after the gas bubble is in the eye (can also mark the meridian by doing laser to the ora serrata in the quadrant of the retinal tear).
4. Prepare intraocular gas. Use either SF₆ or C₃F₈ drawn into a tuberculin syringe through the filter to provide tamponade of the detachment. Use the smallest bubble needed to cover the pathology, keeping in mind that the gas volume needed to cover a given arc of retina will increase with myopia. Pre-fill the system to remove dead space before drawing up the amount of gas to be injected and attaching a 30-gauge needle. SF₆ will expand 2x and lasts for 1-2 weeks, whereas C₃F₈ will expand 4x and lasts 4-8 weeks. Volume of gas injected: 0.3cc for C₃F₈ gas vs. 0.5-0.6cc for SF₆ (make sure to tap the AC).
5. Set up a sterile stand or towel near the eye for placing instruments. Place 5 or 10% Betadine drops onto the eye. Some surgeons prefer to do a modified lid scrub. In patients with an allergy to Betadine, a broad-spectrum topical antibiotic may be used.
6. An anterior chamber paracentesis can be performed safely at this stage, and is especially useful in patients with glaucoma. The eye is stabilized with a cotton-tip swab, and a 27 or 30-gauge needle attached to a tuberculin syringe is used to enter the anterior chamber at the limbus. 0.2 - 0.4cc of fluid is usually withdrawn from the anterior chamber. Softening the eye also allows for easier gas injection and less change of fish-eggs.
7. Intraocular gas injection. This is done through an entry site in a quadrant away from the detachment. Enter the eye vertically 3.5 - 4mm from the limbus, depending on the lens status, and inject the gas at a moderate pace. Injection of gas too quickly can cause a “fish eggs” phenomenon, which may require gentle tapping on the eye or positioning the bubbles away from the break for 24 hours to allow them to coalesce and avoid subretinal gas. To minimize the chance of fish eggs, it is helpful to pull the needle back a millimeter after the injection has begun to maintain one large gas bubble. Another potential complication is gas injection into the Canal of Petit, in which case it can be seen floating behind the lens as a “donut sign” or “sausage sign”; management may include overnight face-down positioning, which is usually effective, or passive drainage with a 27-gauge needle on a tuberculin syringe partially filled with BSS. Lastly, gas in the anterior chamber likely represents anterior migration due to ruptured zonules and can be managed by pupillary dilation followed by face-down positioning or by AC paracentesis with a 27-gauge needle.
8. Evaluation of IOP. Carefully evaluate the central retinal artery for perfusion and confirm light perception. Loss of pulsations lasting longer than a few minutes requires decompression through an anterior chamber paracentesis.
9. Antibiotic or combination antibiotic/steroid ointment is applied to the eye; patching is optional
10. Instruct the patient on the proper head-positioning; can draw an arrow in the clock hour of the retinal tear, and instruct the patient to position their head so that the "arrow" is pointing straight up; alternatively, can have patient's family take a picture while in the office with the proper head position, so the patient can reference this picture at home to properly position.

Complications

Complications related to elevated intraocular pressure (IOP) can be managed with additional anterior chamber paracentesis or topical/systemic IOP-lowering drops. If the retina fails to re-attach, this can be managed by repeating the PR procedure or be proceeding to retinal surgery (e.g., scleral buckle or pars plana vitrectomy). Endophthalmitis is always a risk , albeit low in this type of procedure, and standard of care should be followed if this were to occur.

Anterior hyaloidal gas

• Can occur if the needle is not inserted deeply enough or if it is inserted too anteriorly.
• Manage by placing the patient face down for 24-48 hours. As the gas expands, it usually will break through the anterior hyaloid.
• If above fails in 24-48 hours, a 27g needle on a plungerless 3-cc syringe (with 1cc of sterile water so that the gas externalization process can be better-visualized) is reinserted in the previous gas insertion site. Gas bubbles are aspirated from the Space of Petit in a controlled manner. Reinjection of gas with proper needle placement may be necessary to close the break.

Subretinal gas

• Can occur because the injection site chosen was too close to the break, the gas was injected incorrectly under the retina, or the gas was injected in "fish egg" form (smaller bubbles are more easily mobilized into the subretinal space).
• Manage by attempting to position the patient so that the gas is able to work its way back into the vitreous cavity. Patient may need to be taken to the operating room to perform pars plana vitrectomy and removal of subretinal gas to avoid retinal tears due to gas expansion in the subretinal space.
  • A small amount of subretinal gas can be resorbed and may not need positioning.

Gas in the anterior chamber

• Fish eggs may enter the A/C if there is missing lens capsule or zonular compromise. This often happens in eyes with an anterior chamber intraocular lens.
• As the gas can expand the seclude the pupil, this observation must be managed by dilating the pupil and positioning the patient face-down to allow the gas to return to the vitreous cavity.

Postoperative Care

• Positioning for 5-8 days to orient gas bubble at the site of the tear(s). The patient must position for 16 hours per day, with 15-minute breaks each hour.
• Antibiotic eyedrops four times per day, usually for 1 week
• Patient is examined daily until the macula is attached; partial or total re-attachment can be seen within hours; if the retina is not progressively attached over the following 2-3 days, suspect that something is wrong - e.g., new break, missed break, small gas size, patient not positioning, etc. The exception to this rule is with peripheral inferior subretinal fluid which may persist for weeks to months (but should still trend in a decreasing amount)
• Once the macula is completely attached, the patient can be seen weekly for 2 weeks, and then monthly for a total follow-up period of 3 months.
• Appropriate management of postoperative complications and additional surgery as indicated

Results

Pneumatic retinopexy is a good option for RRD surgery. PIVOT study (REFERENCE) considers pneumatic retinopexy as the first-line treatment for RRD in patients fulfilling the recruitment criteria and shows superior VA, less metamorphopsia, and morbidity compared to PPV. The primary anatomic success in the pneumatic retinopexy group at 12 months was 80.8% versus 93.2% undergoing PPV, with 98.7% and 98.6%, respectively, achieving secondary anatomic success. The cataract surgery required in the pneumatic retinopexy group before 12 months was 16% compared to 65% of phakic patients in PPV. VA of the pneumatic retinopexy group at 6 months was 78.4±12.3 letters compared to 68.5±17.8 letters in the PPV group.^[7]

Additional Resources

1. Vitreoretinal Surgical Techniques. Gholam A. Peyman, 2006.
2. Hillier RJ, Felfeli T, Berger AR, et al. The Pneumatic Retinopexy versus Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial (PIVOT). Ophthalmology. 2019 Apr;126(4):531-9.
3. https://www.aao.org/eyenet/article/when-and-how-to-use-pneumatic-retinopexy

References