Evaluation of the Greenbaum sub-Tenon's block.

Area of Science:

• Ophthalmology
• Anesthesiology

Background:

• Phacoemulsification with intraocular lens implantation is a common cataract surgery.
• Effective local anesthesia and akinesia are crucial for successful surgical outcomes.
• Sub-Tenon's block is a frequently used technique for ophthalmic anesthesia.

Purpose of the Study:

• To determine the optimal volume of local anesthetic for Greenbaum sub-Tenon's block.
• To evaluate the efficacy of varying anesthetic volumes on akinesia, anesthesia, and patient comfort.

Main Methods:

• Prospective, randomized, blind study involving 40 patients undergoing cataract surgery.
• Sub-Tenon's injection of 2% lidocaine with epinephrine and hyaluronidase in volumes of 2, 3, 4, or 5 ml.
• Assessment of ocular movements, anesthesia, pain, and complications.

Main Results:

• 4 and 5 ml volumes achieved akinesia and anesthesia within 5 minutes, eliminating the need for supplementary injections.
• Higher volumes (4-5 ml) significantly reduced eyelid movements.
• Minor complications like chemosis and conjunctival hemorrhage occurred but did not impede surgery.
• 10-15% of patients reported mild discomfort during injection.

Conclusions:

• 4-5 ml of 2% lidocaine with epinephrine and hyaluronidase is the optimal volume for Greenbaum sub-Tenon's block.
• This volume ensures adequate akinesia, anesthesia, and reduced lid mobility for phacoemulsification.
• The technique is safe and effective, with minimal intraoperative complications.