Triplanar transscleral sclerotomies show high rates of unsutured wound closure

The escape of vitreous, gas or fluid may be less frequent after sutureless triplanar sclerotomy for small-gauge vitrectomy.

Vinit B. Mahajan

High rates of unsutured wound closure may be achieved using a novel triplanar technique for transscleral sclerotomy, a study found.

“Going back to the first principles of surgery, wounds that take advantage of the natural surgical anatomy are likely to have better closure,” Vinit B. Mahajan, MD, PhD, senior study author, told Ocular Surgery News. “Triplanar wounds have been constructed in several human tissues, and three surfaces are thought to achieve better wound apposition and present a greater barrier to the [leakage] of fluid and small molecules.”

The prospective, consecutive case series, published in Archives of Ophthalmology, assessed primary vitrectomy cases in which triplanar transscleral tunnel wounds were constructed using a 23-gauge trocar/cannula microvitrectomy system (Alcon); 180 sclerotomies were performed in 60 eyes, with subsequent postoperative air-fluid exchange and cannula removal.

To assess the integrity of scleral wounds, the conjunctiva was dissected and wounds were directly tested for the escape of vitreous, gas and fluid through application of a cellulose sponge, observation of gas escape and examination by the Seidel method, respectively.

“To the best of our knowledge, this is the first study to create and test triplanar sclerotomy techniques intraoperatively and histologically in human eyes. It is also the first to apply standard methods for small-gauge sclerotomy wound testing in the [operating room], rather than relying on postoperative surrogate measures like intraocular pressure and wound imaging,” Dr. Mahajan said.

Testing scleral wound leaks

There is no established test to determine what constitutes an open or closed wound, making the intraoperative assessment of wound construction complex, the study authors said.

While all three methods used to detect leakage demonstrated at least one incidence of outflow, no single method was proven most sensitive. The authors suggested continued use of multiple methods.

“Although these are the standard intraoperative tests for anatomic closure of ophthalmic wounds, none of these tests are perfect. They do not indicate whether [the wounds] remained closed postoperatively,” Ryan Tarantola, MD, study co-author, said.

However, the higher incidence of leakage detection through the observation of gas escape may suggest this method’s superior sensitivity, he said.

None of the observed leaks tested positive via more than one testing method.

“It is possible that if the sclerotomy is filled with either vitreous, gas or fluid, one element could block the others from reaching the external wound,” Dr. Mahajan said. “For example, if vitreous is blocking the sclerotomy, it is conceivable that it is more difficult for fluid or gas to pass through it.”

Study results

A 93.9% rate of wound closure was observed, with 11 sclerotomies remaining open. Of these, eight leaked gas, two showed positive results for the Seidel test and one had vitreous leak.

“It is possible to create complex scleral wound structures that seem to achieve good intraoperative wound closure, but it is never 100%,” Dr. Mahajan said. “If there is any doubt, or if the patient has risk factors for postoperative endophthalmitis, we do not hesitate to place a suture.”

More complex cases involving longer surgical duration, more instrument passes and increased wound manipulation were associated with higher rates of leakage. An 81% rate of wound closure was observed for complicated retinal detachment cases with proliferative vitreoretinopathy.

The study authors suggested that surgeons who are transitioning to 23-gauge vitrectomy should create sclerotomies after conjunctival dissection in order to better understand surgical consequences and closure rates for their individual method of wound construction.

“I have noticed a rapid improvement in wound construction quality if our fellows dissect the conjunctiva and get a direct view of the scleral wound for their first several small-gauge cases,” Dr. Mahajan said.

He added that it is almost impossible to determine whether a sclerotomy is closed when the conjunctiva obscures the wound from being tested.

In addition, low rates of suture placement (6.1%) and postoperative day 1 hypotony (1.7%) were observed. The study, however, was limited by a lack of comparison between triplanar sclerotomy wounds and biplanar and uniplanar wounds, suggesting the need for further analysis.

“Our study suggests that properly constructed, triplanar, 23-gauge scleral tunnel wounds have low permeability to vitreous, gas and fluid and provide an excellent option when choosing a method for sclerotomy incision,” the study authors wrote. – by Michelle Pagnani

Reference:

• Mahajan VB, Tarantola RM, Graff JM, et al. Sutureless triplanar sclerotomy for 23-gauge vitrectomy. Arch Ophthalmol. 2011;129(5):585-590.

• Vinit B. Mahajan, MD, PhD, can be reached at the Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA 52242; 319-356-8161; email: vinit-mahajan@uiowa.edu.
• Disclosure: Dr. Mahajan has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.

In this series of pars plana vitrectomy cases, all eyes had a triplanar 23-gauge trocar insertion and a partial fluid-air exchange at the end of surgery. A high rate of sclerotomy closure without sutures was achieved. As acknowledged by the study authors, we do not know if the triplanar trocar insertion is any better than a biplanar or even uniplanar insertion at a similar average angle of approach. Furthermore, the routine use of air at the end of surgery is likely to minimize wound leakage and probably contributed to the comparatively low rate of wound leakage and suturing. We also do not know if the added step of performing a conjunctival opening before inserting the trocar has any benefits. It adds time to the procedure and probably adds some degree of postoperative discomfort. Additionally, it may make the eye more susceptible to infection due to the larger conjunctival opening.

– Carl D. Regillo, MD
OSN Retina/Vitreous Board Member
Disclosure:Dr. Regillo receives research support from and is a consultant for Alcon.