An audit of peribulbar blockade using 15 mm, 25 mm and 37.5 mm needles, and sub‐Tenon's injection*

Abstract

SummaryThe efficacy of peribulbar anaesthesia performed with short, medium and long needles, with subTenon's injection as a control, was audited. Two hundred patients undergoing cataract surgery underwent peribulbar injection using 25G needles of the following lengths: 15 mm, 25 mm or 37.5 mm. Sub-Tenon's injections were performed with a curved 25-mm sub-Tenon anaesthesia cannula. The injection technique, ocular akinesia and analgesia scoring system, and supplementary injection protocols were standardised. After initial injections of local anaesthetic via the subTenon's cannula or with 37.5 mm, 25 mm and 15 mm needles, supplementation was required in one (2%), 13 (26%), 22 (44%) and 32 (64%) of patients, respectively; the total number of supplementary injections required were 1, 16, 35 and 47, respectively. It is concluded that the efficacy of peribulbar anaesthesia depends upon the proximity of the deposition of local anaesthetic solution either to the globe or orbital apex. These data justify the classification of peribulbar anaesthesia into: circum-ocular (sub-Tenon's, episcleral), peri-ocular (anterior, superficial); peri-conal (posterior, deep) and apical (ultra-deep) for teaching purposes.

Local anesthesia for cataract surgery

“…of the local anesthetic solution to the globe or the orbital apex. 71 Consequently, peribulbar anesthesia can be classified as circumocular (sub-Tenon episcleral), periocular (anterior, superficial), periconal (posterior, deep), and apical (ultra deep). Peribulbar blockade can lead to significant reduction in pulsatile ocular blood flow and IOP, which may be of benefit in certain operations.…”

Complications of Ophthalmic Regional Blocks: Their Treatment and Prevention

“…Surgical decompression of the optic nerve sheath may be indicated [17]. This complication can be avoided by having a good knowledge of anatomy and by appropriate placement of a short needle <31 mm while the eye is in the neutral position [6, 32, 33]. …”

“…The terminology used for ophthalmic regional blocks is controversial [6]. A name based on the anatomical placement of a needle or cannula is accepted widely [7].…”

Medial Canthus Single-Injection Peribulbar Anesthesia: A Prospective Randomized Comparison With Classic Double-Injection Peribulbar Anesthesia

“…Puncture was performed with a 25-gauge, 35-mm, short-beveled needle. 9 The depth of injection was clinically determined for each patient, but the needle was never introduced more than 30 mm for the inferotemporal puncture of the peribulbar anesthesia and never more than 20 mm for the caruncular puncture.…”