Suspension material key to ptosis repair

February 1, 2011

Frontalis suspension, the ptosis surgery of choice for poor levator function due to congenital or acquired ptosis, can be performed with synthetic materials or fascia lata allografts or autografts.

Chicago-Frontalis suspension, the ptosis surgery of choice for poor levator function due to congenital or acquired ptosis, can be performed with synthetic materials or fascia lata allografts or autografts. Two surgeons debated the pros and cons of each treatment in a point/counterpoint presentation at the inaugural oculofacial plastic surgery subspecialty day held prior to the annual meeting of the American Academy of Ophthalmology.

Speaking first, Francois Codère, MD, associate professor of ophthalmology at both the Université de Montréal and McGill University in Montreal, Quebec, Canada, said that an autogenous sling meets two characteristics of the ideal suspension material: biocompatibility and stability.

"Once it has been put in, it has been shown that it integrates fully into the tissue, and in fact revision might be a little more difficult because of that," Dr. Codère said.

"You have to remember that children with congenital ptosis will have to [undergo suspension] for 70 years or more, and it's very important that we have something very stable," Dr. Codère said. "Most synthetic materials come and go. Autogenous fascia has a tendency to stay on."

It is generally agreed, however, that synthetic slings are preferable for severe acquired ptosis, such as neurogenic and myogenic cases, including myasthenia.

One of the reasons behind Dr. Codère's preference for autogenous slings is the high long-term incidence of infection with synthetic material. Studies have shown that synthetic material will get infected or create granulomas in at least 10% of cases, with the infection rates reaching 15% to 20% or higher with some materials, Dr. Codère said.

He added that with a porous material such as Gore-Tex, extensive lid dissection may be required to remove the infected and adherent suspensory material.

Recurrence is also a significant problem with synthetic materials and bank fascia. In one study, recurrence occurred in 13% of cases with silastic and 35% with bank fascia. In a separate study of patients who had undergone frontalis suspension with different materials, 26% of patients had recurrence at 1 year. The lowest rate among synthetic materials was 15% with Gore-Tex.

With autogenous materials, the long-term recurrence rates are very low. Dr. Codère cited one study in which tissue was incised 45 years after frontalis suspension ptosis repair; living fascia was still present and had become fully integrated.

Since scarring can a problem when using autogenous suspension material, careful closure is important. Dr. Codère suggested that muscle prolapse could be prevented by closing the exposed area of fascia tendon before closing the skin.

Alloplastic slings

Following Dr. Codère, Christine C. Nelson, MD, pointed out that autogenous fascia is not the ideal choice for patients who need a material that will provide more "stretch" in the oblique to avoid bad exposure. Dr. Nelson is professor, ophthalmology and visual sciences and professor, Department of Surgery, Section of Plastic Surgery, at the University of Michigan Kellogg Eye Center, Ann Arbor.

When she uses a synthetic material for frontalis suspension ptosis repair, Dr. Nelson typically chooses silicone, which can be used in any age child and is easily threaded, or banked allograft fascia lata.

"It's more cost effective due to the shorter operating room time, there's no comorbidity at a second surgical site, and not all patients have an adequate donor site (for an autograft)," she said.

Dr. Nelson also compared the features of the different graft materials. Banked fascia, for example, comes in various sizes and shapes and can be reconstituted easily at the time of surgery. Fresh fascia graft requirements include at least 15 cm of upper leg length, which often rules out its use in a short child. The surgeon also must have the skill to harvest donor fascia tissue as well as special instrumentation, and harvesting the tissue lengthens the operative time while increasing the cost of the repair.

Harvesting the graft also leaves a second scar. For this reason, parents of little girls often choose not to go this route. Although the scar usually heals well, it would be more visible on the smooth leg of a girl than the hairy leg of a boy, Dr. Nelson remarked, adding that Dr. Codere had not included any pictures of girls in mini skirts when showing follow-up pictures of his patients.

As an alternative, silicone offers a number of advantages as a suspensory material. It is adjustable if a change in lid height is necessary because of exposure or lagophthalmos, and it can be easily removed if the exposure is too great. In addition, it allows stretching for lid closure with forced blinking.

"In our experience over 30 years, we've done very well with silicone," Dr. Nelson said. "It's certainly more cost effective than other materials, and we have no increased operating room time.

"The advantage of donor fascia is relative ease of height adjustment," she continued. "We've had 20 years of experience with very few complications, and we have not seen late ptosis recurrence. There's no secondary leg scar and no bulging of the muscle to the fascia."

In a study at the University of Michigan Kellogg Eye Center involving 24 patients with silicone slings and 21 with donor fascia, recurrent ptosis was observed in several of the patients with the synthetic material.

However, this was due in part to the inclusion of patients with neurogenic conditions that were "undercorrected" to reduce the risk of developing lagophthalmos. The complications in the patients with silicone slings included two cases of migration and one instance in which the sling slipped and loosened. With the donor fascia, the only complication was one case of cellulitis.

"There's no question that there's better biocompatibility when using autografts," Dr. Nelson concluded. "However, the final functional outcome in ptosis recurrence, at least in our experience in pediatric and adult patients, really showed no statistical difference."

FYI

Francois Codère, MD
Phone: 514/843-1620
E-mail: francois.codere@mcgill.ca

Christine C. Nelson, MD
Phone: 734/763-1415
E-mail: cnelson@umich.edu

Neither Dr. Codère nor Dr. Nelson reported any financial disclosures.