September 2009




Residents & complication rates

by Matt Young EyeWorld Contributing Editor

Pseudoexfoliation of lens capsule, a major complication confounding residents

Although researchers have analyzed intraoperative complication rates among residents performing cataract surgery, a new study reveals more detail about what exactly emerging ophthalmologists have trouble with—and what poses little problem. “Intraoperative complication rates in resident-performed phacoemulsification surgery in the published literature range from 2.0% to 14.7%,” reported study co-author Ayman Naseri, M.D., Department of Ophthalmology, San Francisco Veterans Administration Medical Center, San Francisco, and colleagues, online in January 2009 in Ophthalmology. “However, [previous studies] have not systematically analyzed potential risk factors for intraoperative complications in resident-performed phacoemulsification surgery. Prior studies of resident-performed cataract surgery have also excluded cases considered to be challenging.”

Residents in Dr. Naseri’s study, however, took challenging cataract cases head on. Not so surprisingly, mature nuclei and zonular pathology led to an increased risk of complications for residents. But other potential pitfalls, such as patients with intraoperative floppy iris syndrome, posed no additional risk when operated upon by residents. “This study may help other residency programs identify strategies to decrease complication rates in resident-performed phacoemulsification surgery,” Dr. Naseri noted.

Problem areas

Dr. Naseri analyzed 320 consecutive phacoemulsification cases performed by residents. Major intraoperative complications occurred in 15 of 320 cases (4.7%). The 15 major complications included: • Vitreous loss (10 cases, three of which included dropped nuclear fragments and one of which included corneal wound burn) • Two malpositioned IOLs, which necessitated reoperation • One wrong IOL power, leading to a second operation • One corneal wound burn • One post-op iris prolapse, which led to wound revision • A further 28 minor complications included failure to complete a capsulorrhexis (18 patients), iris prolapse (eight patients), and unexpected hyperopic refractive outcomes (four patients). “Major complications were strongly associated with challenging case features,” Dr. Naseri reported. “Cases with mature lenses or potential zonular pathology (antecedent trauma or pseudoexfoliation) presented the highest odds of a major complication: 18.9 and 26.2 respectively.”

Specifically, 4 of 7 cases (57%) with mature cataracts had major complications. Three of 6 cases (50%) with potential zonular pathology had complications. In univariate analysis, major complications were statistically significantly associated with challenging cases, wound type, phacoemulsification technique, and pre-op visual acuity. Looking at the data in more detail, however, shows that not all challenging cases increase risk for major complications. Although small pupil size cases are undoubtedly challenging, for example, the feature did not lead to an increased risk of a major complication. “This may be due to proactive pupil management strategies used because of an increased awareness of intraoperative floppy iris syndrome,” Dr. Naseri wrote. Further, he reported, “Small pupils, corneal disease, monocular patients, shallow chambers, post-vitrectomy cataracts, and combined procedures were not strongly associated with major complications.”

Phacoemulsification technique factored into whether or not patients were likely to experience complications, but only in a minor way. “The divide and conquer technique compared with nuclear chopping was borderline statistically significant for increased odds of major complication,” Dr. Naseri reported. “All residents learned phacoemulsification with the divide and conquer technique and then transitioned to chopping, which would suggest that perhaps resident inexperience was responsible for the association between the technique and complications.”

The researchers do not believe the divide and conquer technique is flawed. Notably, resident experience—or the lack thereof—was not associated with increased complications, which contrasted with researchers’ expectations. Attending surgeon features also did not factor into higher complication rates. “Because most (87%) of the phacoemulsification cases were attended by two VA [vascular] attendings, one might anticipate a higher complication rate among cases attended by visiting attendings, who were not as familiar with the residents’ surgical skills, the operating room equipment, and staff,” Dr. Naseri noted. This, however, was not the case. Finally, although previous research found that individual skill was a factor in complication rates, this study did not. “The low complication rate was not driven by a few excellent resident surgeons,” Dr. Naseri reported. John D. Sheppard, M.D., professor of ophthalmology, microbiology, and immunology, Eastern Virginia Medical School, Norfolk, Va., has found other difficulties with residents beyond what was noted in this report. “My residents have trouble with pseudoexfoliation,” Dr. Sheppard said. “Any problems with a bad capsule can make things difficult.” Uncooperative patients also pose big difficulties, he said. “In the context of a resident having trouble with an uncooperative patient, anxiety level is increased and the complication rate is increased,” he said. Dr. Sheppard agreed that resident problems do not seem to be affected by the nature of the attending surgeons. He also added that a shallow orbit makes things easier, and therefore a deep orbit makes cases more difficult for residents.

Editors’ note: Dr. Naseri has no financial interests related to this study. Dr. Sheppard has no financial interests related to his comments.

Contact information

Sheppard: 757-622-2200,

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