A new local anesthesia technique for cataract extraction by one quadrant sub-Tenon's infiltration.

Abstract

A new technique of local anaesthetic administration has been used for 50 patients undergoing cataract extraction. The simple technique involves direct transconjunctival infiltration of local anaesthetic directly to the sub-Tenon's space, in the inferior-nasal quadrant, using a blunt 19-gauge Southampton cannula. This method seeks to avoid the risks ofretrobulbar haemorrhage, perforation ofthe globe, damage to the optic nerve, and injection into the subarachnoid space, whilst providing prolonged and reliable anaesthesia. Akinesia is achieved by the inferior-nasal placement of solution and if not sufficient, a top-up can easily be given. Patients graded any discomfort or pain using a 10 cm visual analogue graphical pain score chart with numerical and descriptive rating scale. The delivery of 50:50 mixture of lignocaine 2% and bupivacaine 0 5% anaesthetic was evaluated by patients with a median response of 'slight discomfort'. The operative procedure was graded with a median of 'no pain or discomfort', both for extracapsular cataract extraction and phakoemulsification. This is a new, modified, sub-Tenon technique which is simple, reliable, and which offers excellent anaesthesia and akinesia and avoids a sharp instrument being passed into the orbit. (BrJ Ophthalmol 1992; 76: 670674) In 1884 Knapp reported successful cataract extraction by topical anaesthesia using frequent drops of 5% cocaine. He commented on the need for more extensive anaesthesia if the iris is to be anaesthetised. Describing a technique for enucleation, he reported the successful use of a retrobulbar injection,' rotating the globe nasally and introducing a needle through the muscle cone temporally. In 1884 Turnbull also described a local anaesthetic technique for enucleation, where topical 4% cocaine was applied to the cornea and conjunctiva, followed by the opening ofTenon's fascia and cocaine being dropped into the cut.2 Blunt pointed scissors which were curved on the flat were introduced from the nasal side and drops instilled. This was reported as successful in causing anaesthesia and vasoconstriction.Today various methods oflocal anaesthesia are in use for cataract extraction including retrobulbar,3 peribulbar,4 subconjunctival,5 and subTenon's6 application oflocal anaesthetic solution. Moorfields Eye Hospital, The desire to find an alternative to retrobulbar City Road, London EC1V anaesthesia has been caused by a variety of 2PD

Ultrasonic localization of anaesthetic fluid using sub-Tenon's cannulae of three different lengths

“…The volume of local anaesthetic chosen may appear excessive, but most published studies advocate this volume 1,9,12,13 to achieve anaesthesia, adequate reduction of ocular movements, and to reduce the need for supplementary injections. The incidence of pain on injection, 1,12,14,15 chemosis, 1,9,12,14 and conjunctival haemorrhage 1,9,12,14 are similar to those in other published studies. Chemosis was noted with all three cannulae, suggesting that fluid often tends to spread anteriorly, irrespective of the length of the cannula.…”

“…Local anaesthetic agents can be administered into sub-Tenon's space via long 1 (Stevens: Visitec: metal 19 G, 2. 54 cm), intermediate 2 (Kumar-Dodds: Simco, plastic 22 G, 1.8 cm), or short 3 (Greenbaum: Alcon, plastic 14 G, 1.2 cm) sub-Tenon's cannulae.…”

A comparison of three sub-Tenon's cannulae

“…Delivery of local anaesthetic solution into the sub-Tenon space has been described using a variety of cannulae. [2][3][4] The three most commonly used cannulae at the North Riding Infirmary, Middlesbrough, UK include a 12 mm plastic anterior sub-Tenon cannula (Greenbaum cannula, Figure 1), an 18 mm plastic mid subTenon cannula (Kumar-Dodds cannula, Figure 2), and a 25 mm metal curved posterior sub-Tenon (Stevens cannula, Figure 3). Serious complications of sub-Tenon anaesthesia are rare but have been documented.…”

“…[5][6][7] Minor complications are more common, and include pain on injection (44%), chemosis (25-100%), and conjunctival haemorrhage (20-100%). 2,8,9 The influence of dedicated sub-Tenon cannulae on the development of akinesia and the incidence of complications has received less attention. LaMarnierre et al 10 compared the Greenbaum cannula method with the Ripart injection technique, and found no difference in analgesia, but a higher incidence of chemosis with the Greenbaum cannula.…”

Effect of hyaluronidase on ocular motility and eyelid function in sub-Tenon's anaesthesia: randomised controlled trial

“…1 It is relatively quick and effective, and allows the use of a blunt cannula thereby avoiding the risk of a needle near the globe.…”