TOPICAL VERSUS SUB-TENON ANESTHESIA WITHOUT SEDATION IN CATARACT SURGERY (2002)

Zafirakis P, Voudouri A, Rowe S, et al. Topical versus sub-Tenon's anesthesia without sedation in cataract surgery. J Cataract Refract Surg 2001;27:873–879. Original study reprint requests: Panayotis Zafirakis, 8 Kileler Street, K. Ilioupolis, 16346, Athens, Greece. Research Objective To compare pain control using topical anesthesia with that using sub-Tenon anesthesia for clear corneal phacoemulsification cataract surgery and foldable intraocular lens (IOL) implantation. Study Design A prospective, randomized clinical trial. Locations Department of Ophthalmology, General Hospital Asklepeion Voulas and General Hospital of Athens, University of Athens, Athens, Greece. Funding Sources None listed. Relevant Methodology One hundred consecutive patients scheduled for bilateral cataract surgery 1 to 2 months apart were prospectively randomized to receive topical anesthesia (100 eyes) or sub-Tenon anesthesia (100 eyes). The randomization was stratified so that one half of first-eye surgeries and one half of second-eye surgeries were assigned to each anesthesia group, with each patient receiving each type of anesthesia once. All patients had clear corneal phacoemulsification with foldable IOL implantation. Patients were asked to rate their pain level on a 10-point scale for 4 periods: during the administration of the anesthetic agent, during surgery, immediately after surgery, and 24 hours postoperatively. The surgeon recorded his subjective assessment of ease of surgery and surgical complications using a standardized template. Outcome Measures Pain rating scale scores as listed above. Results Eighty-one percent of patients who received topical anesthesia and 8% of patients who received sub-Tenon anesthesia reported no pain during delivery of the anesthetic agent. The mean pain score was 0.19 ± 0.39 (SD) in the topical group and 1.35 ± 0.63 in the sub-Tenon group. The difference between groups was statistically significant (p < 0.001). Seventy-two percent of patients in the topical anesthesia group and 86% in the sub-Tenon anesthesia group reported no pain or slight discomfort during surgery (mean score 1.13 ± 1.57 and 0.57 ± 1.28, respectively) (p < 0.001). Ninety percent of topical anesthesia patients and 100% of sub-Tenon anesthesia patients reported no pain or slight discomfort for 30 minutes postoperatively (mean score 0.80 ± 0.93 and 0.12 ± 036, respectively) (p < 0.001). All patients in the topical anesthesia group and 77% in the sub-Tenon group reported no pain 24 hours postoperatively (mean pain 0.00 ± 0.00 and 0.23 ± 0.40, respectively) (p < 0.001). Complications including prolonged akinesia of the globe, chemosis, and conjunctival hemorrhage occurred significantly more frequently in the sub-Tenon than in the topical group (p < 0.001). Conclusions Patients having cataract surgery under topical anesthesia had no more intraoperative and postoperative discomfort than patients receiving sub-Tenon anesthesia. However, patients having topical anesthesia reported less pain during its administration and had fewer complications. Both anesthesia methods provided high levels of pain control without additional sedation. Comment Many alternate techniques of anesthesia for ophthalmic surgery have arisen in the last 10 years. Replacing the traditional needle-delivered anesthetic blocks is the use of cannulas for sub-Tenon infusion as well as intraocular and topical administration of anesthetics. Several studies have compared the safety of administration and effectiveness of various anesthetic techniques with mixed results. This study is a randomized, prospective trial comparing pain of topical versus sub-Tenon anesthesia during clear corneal phacoemulsification. The study demonstrates a statistically significant increase in a patient's pain assessment on administration of sub-Tenon anesthesia compared to topical and notes that postoperative pain is significantly greater in the topical group immediately after surgery, whereas discomfort is greater in the sub-Tenon group at 24 hours. However, scientific conclusions regarding the highly subjective evaluation of pain should be met with trepidation. There are many confounding variables when comparing anesthetic techniques with regard to pain. Most notably, patient selection, length and type of surgical procedure, and the use of oral or intravenous sedation can all affect a patient's perception of pain during a surgical manipulation. The study highlights two modalities that are safe and effective techniques of providing anesthesia for cataract extraction. They both eliminate many risks associated with the needle-driven techniques including globe perforation, retrobulbar hemorrhage, extraocular muscle damage, and respiratory depression and are a welcome addition to the armamentarium of techniques for administration of ophthalmic anesthesia.