This large survey of strabismus surgeons demonstrated the need for better error reduction protocols in this field. The findings included that the performance of a “timeout” failed to prevent errors in 38 percent of cases and that surgeons who used site marking were less likely to experience errors than those who didn’t.
The authors write that protocols to reduce surgical errors, such as the Joint Commission on Accreditation of Healthcare Organization’s Universal Protocol, may be less effective in addressing errors in strabismus surgery.
Strabismus surgery can be performed on multiple muscles in one or both eyes. Marking the correct eye would not prevent a surgeon from operating on the incorrect muscle. Furthermore, the terms and abbreviations for esotropia, exotropia, hypertropia, hypotropia, recession and resection can be easily mistranscribed or confused. Also, because the surgical site is small, a nurse or an anesthesiologist cannot easily verify that the muscle undergoing the operation is the intended muscle. Finally, the surgeon generally operates sitting at the patient's head, creating the potential for right/left and up/down confusion.
The authors surveyed strabismus surgeons to estimate the prevalence of errors in strabismus surgery and to assess factors that may have contributed to them. Five hundred seventeen strabismus surgeons completed the survey, which was emailed to members of the American Association for Pediatric Ophthalmology and Strabismus or administered to them at the 2011 annual meeting.
The mean error rate was 1 in 2,506 operations. Surgeons who performed fewer than the median 1,500 procedures had an error rate 5.9 times higher than surgeons who performed more than the median. One-third of respondents self-reported having operated on the wrong eye or muscle or performed the wrong procedure at least once.
The most common factors contributing to errors were confusion between the type of deviation and/or surgical procedure (29.8 percent), globe torsion (17.5 percent) leading primarily to inadvertent operation on the inferior rectus rather than the intended medial rectus muscle, and inattention and/or distraction (16.7 percent). Running more than one operating room and failing to mark eye muscles preoperatively were associated with an increased likelihood of error.
They found that in 53 of 139 surgical error cases (38.1 percent), a timeout had been performed but failed to prevent an error. They also found that surgeons who marked eye muscles were less likely to experience errors than those who did not.
They conclude that the strabismus surgery timeout should include the deviation, the specific muscles to undergo operation, and the intended procedure. Involving an assistant in preoperative verification of the specific eye muscles and surgical procedure would also help. They recommend that strabismus surgeons consider modifying the Universal Protocol to better address their subspecialty-specific causes of error.