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Two studies evaluate modifications to DCR
One study examined the role of mitomycin-C in DCR; the other involved 45 children who underwent nonlaser endonasal DCR.
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With a few modifications, surgeons can decrease complications associated with endonasal dacryocystorhinostomy and perform the procedure in a wider range of patients, according to two presentations at the American Society of Plastic and Reconstructive Surgeons.
The presenters agreed that the results of their respective studies are not directly comparable, but their findings suggest a possibility for the expanded use of nonlaser endonasal dacryocystorhinostomy (DCR) for nasolacrimal duct obstruction.
In his study, Peter J. Dolman, MD, FRCSC, addressed mitomycin-C (MMC)-related complications by studying whether antimetabolites are an integral part of the procedure.
Despite a lack of prospective studies, “Surgeons have increasingly reported using mitomycin,” he said. “There aren’t enough studies proving whether it is effective or not. And that’s what we were trying to prove in our study.”
Technique
The study compared 58 patients who underwent DCR with MMC with 118 patients who underwent the procedure without the use of antimetabolites.
In all cases, Dr. Dolman removed the nasal mucosa with a sickle knife and ethmoid forceps and created a 1-cm bony ostium with a Kerrison 3-mm up-biting rongeur. He then created a flap in the lacrimal sac duct and irrigated both the upper and lower canaliculus to ensure patency. A silicone stent was implanted in every patient for 3 months.
Test patients received 0.3 mg/mL of MMC applied against the ostium with a cotton swab for 3 minutes.
At 1-year follow-up, Dr. Dolman reported successful outcomes (defined as a significant reduction in tearing and a patent ostium with irrigation) in 93% of the MMC group and 94% of the control group. There was no statistical difference between the two groups.
“Mitomycin really has no benefit in terms of improving surgical outcome,” he told Ocular Surgery News. “We’re recommending that [surgeons] don’t use it.”
Clinical judgment
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The second part of Dr. Dolman’s study followed 32 patients who underwent bilateral DCR with MMC applied to one side. When asked to compare the two sides, 84% of patients reported no symptomatic difference between them.
Dr. Dolman noted that surgeons are using MMC based on their clinical judgment; published reports have offered conflicting evidence of its efficacy. He suggested that the use of MMC in cancer and glaucoma treatments has spurred the interest of oculoplastic surgeons.
He pointed to the complications observed after the use of MMC, particularly bleb-related complications in glaucoma patients. Other complications in the literature have included bone marrow suppression (systemic use), cataract (topical use), keratitis and corneal-scleral melt. No complications were observed in this study.
In addition, Dr. Dolman said, MMC is expensive and increases the length of the procedure.
“Given the cost of the drug and the additional surgical time of 3 minutes for an average 20-minute case, we would not recommend its use at this dose for routine primary endonasal DCR,” he said at the meeting.
Dr. Dolman said that he is currently conducting a survey of MMC usage among oculoplastic surgeons.
Pediatric procedures
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(Photographs courtesy of Angela Maria Dolmetsch, MD.) |
Angela Maria Dolmetsch, MD, conducted a study of nonlaser endoscopic endonasal DCR in children to address the lack of such studies in the literature. She noted that surgeons typically opt to perform external DCR in young patients or, when possible, delay the procedure until the child is older. Although effective, external DCRs alter the medial canthal structures and produce a visible facial scar, Dr. Dolmetsch said.
“Endonasal DCR is not a popular procedure in children because young patients have the tendency to scar more readily and produce more fibrous tissue than adults,” she said. “When DCRs are performed in children, there’s always the concern that they’re going to fail, particularly when performed endoscopically, as has been demonstrated in previous studies in the literature.”
Forty-five patients between the ages of 5 months and 16 years underwent nonlaser endonasal DCR with the use of MMC. Forty-one children had congenital nasolacrimal duct obstruction, three had traumatic obstruction, and one had obstruction with no apparent cause.
During the procedure, surgeons removed the nasal mucosa, lacrimal bone and a fragment of the frontal process of the maxilla. They then excised the medial wall of the lacrimal sac and applied 0.5 mg/mL of MMC at the osteotomy site for 5 minutes. Silastic tubing was left in place after the procedure.
Modifications
Dr. Dolmetsch noted that she made minimal modifications to perform the procedure in pediatric patients. Surgeons can even use the same 4-mm endoscope that they use in adults, she said.
There is a learning curve, she noted.
“In children, it is possible, if you’re not careful enough, to get a CSF leak,” Dr. Dolmetsch said. “Really know your nasal anatomy before performing [endonasal DCR] on children.”
With a mean follow-up of 18 months, Dr. Dolmetsch reported that 96% of patients achieved success (defined as resolution of epiphora, absence of discharge and a normal dye disappearance test).
Complications
The most common complications were prolapsed silicone tubes in 13% of patients and ocular irritation secondary to suspension of ocular steroids in 11%. Two cases became obstructed and were reoperated. There were no side effects or complications associated with the use of MMC.
In an interview, Dr. Dolmetsch noted that endonasal DCR can be performed when less invasive procedures such as probing or intubation fail or are impossible to perform. She recalled the success she had with a 5-month-old infant who had been treated for acute dacryocystitis with antibiotics for 15 days and had not responded to conservative treatment. The risk of creating a false passage in this patient with acute inflammation made probing dangerous, and external DCR would have been difficult to perform, she said.
With endonasal DCR, she said, “The child did very well. There was complete resolution of the infection and epiphora.”
Dr. Dolmetsch noted that she now has 62 patients age 16 years and younger enrolled in her study with successful outcomes and few complications.
For Your Information:
- Peter J. Dolman, MD, FRCSC, can be reached at UBC Eye Care Centre, 2550 Willow St., Vancouver, British Colombia V5Z 3N9; 604-875-4346; fax: 604-875-4415; e-mail: peterdolman@hotmail.com.
- Angela Maria Dolmetsch, MD, can be reached at the Clinica de Oftalmologia de Cali; Cra. 47 #8C-94, Cons. 211; Cali, Colombia; 572-511-0267; fax: 572-884-2516; e-mail: adolme@calipso.com.co.