Study: Partial vitrectomy technique reduces surgical complications

Two-port procedure with external slit lamp illumination is a safer and less invasive method for all vitreous pathologies that affect the macula.

PADUA, Italy — Partial two-port vitrectomy with external slit lamp illumination is a safer, less invasive technique that decreases the rate of surgery-induced complications, according to a study performed at Sant’Antonio Hospital.

“This technique has several indications, including epiretinal membranes, macular hole, macular edema secondary to [central retinal vein occlusion] or [branch retinal vein occlusion], vitreous hemorrhage and vitreomacular traction. In other words, to all vitreous pathologies that affect the macula,” Roberto Cian, MD, said in an interview with Ocular Surgery News.

Following the recent trend toward partial vitrectomy rather than complete vitrectomy, it is limited to the space between the two arcades of the posterior pole, in the central 30°. It is there that, through a tunnel, the instruments are inserted to carry out the peeling of the membranes that are the cause of retinal traction, macular hole or edema.

This method was originally developed by Didier Ducournau, MD, a consultant at the Clinique Sourdille in Nantes, France.

“I traveled to France several times to learn this surgery, and this convinced me because I had the opportunity to see hundreds of patients successfully treated with this method before I started using it with my own patients,” Dr. Cian said.

Significant innovation

Two small sclerotomies are performed at 12 o’clock, at a 3.5-mm distance from the corneoscleral limbus, to carry out a 20-gauge two-port vitrectomy. This minimally invasive approach is made even safer by a simple but significant innovation: The light source is not internal — incorporated in the instruments — but external, from a conventional slit lamp.

Figure 1. The Tenon capsule is opened.

Figure 2. Diathermy is performed.

Figure 3. The self-blocking infusion cannula is inserted.

Figure 4. The slit lamp is switched on.

Figure 5. Preretinal membrane peeling with microforceps.

Figure 6. The conjunctiva is closed by diathermy. Images: Cian R

“Vitreoretinal surgery normally lasts between 20 minutes and 1 hour. By using the slit lamp, we expose the macula to an illumination of 7,500 lux/mm² compared to the 125,000 lux/mm² of a traditional optic fiber inserted through a third sclerotomy. This almost 20 times less light exposure is significantly less traumatic to the delicate photoreceptors of the retina,” Dr. Cian said.

The technique, he said, requires a learning curve. The movements of the hand that holds the vitrector must be coordinated with those of the microscope in which the slit lamp is attached to obtain an adequate illumination of the operating field.

“The light can follow you to the extreme periphery, but you need some practice,” he said.

At the end of the procedure, preretinal membrane peeling is performed.

The study

The safety and efficacy of this technique was evaluated in a retrospective series of 357 eyes of 354 patients, all of them operated on by Dr. Cian between March 2005 and October 2007. Surgery was carried out under topical anesthesia. The Millennium vitrector (Bausch & Lomb) was used for all cases.

All 354 patients were followed for a minimum of 6 months. Mean visual acuity progressively improved from preoperative 20/100 to 20/63 at 3 months and 20/50 at 6 months.

“The rates of intraoperative and postoperative retinal tears and retinal detachment were comparable or lower (0.5% to 0.9%) than published rates. Cataract formation was very low: only 21% compared to the 80% to 88% we normally had with complete three-port vitrectomy,” he said.

He said sparing such a large portion of vitreous allows a lower incidence of cataract formation because the crystalline lens is protected from the turbulent flow of balanced salt solution fluids during surgery.

“In addition, with this minimally invasive two-port approach, the eyeball undergoes little manipulation, resulting in a faster functional recovery without postoperative discomfort, a more rapid mobilization of the patient and shorter hospitalization,” he said.

He now uses this technique in all the cases in which no abnormalities of the peripheral retina are present. – by Michela Cimberle

• Roberto Cian, MD, can be reached at Ospedale Sant’Antonio, Via Facciolati 71, 35127 Padova, Italy; 39-049-8216729; e-mail: roberto.cian@libero.it.

  

  

  This study shows how, in the era of mini-invasive surgery, the use of a simple instrument like the surgical slit lamp is a perfect way to decrease surgical trauma. External illumination allows us to perform only two sclerotomies instead of three (or four if you use a chandelier), thus minimizing the risk of vitreous incarceration, to decrease phototoxicity and to stabilize the forceps with the free left hand, thus increasing precision and speed.

  This technique, added to the sparing of a large portion of vitreous, leads to a diminished rate of postoperative RD and secondary cataract.

  The only problem, as mentioned by Dr. Cian, is how willing and capable individual surgeons are to accept changes and to divert from the traditional ways of doing things.

  – Didier Ducournau, MD

  Clinique Sourdille, Nantes, France