1. The effect of ophthalmic anaesthesia choice in cataract surgery – A comparison of trainee outcomes. I. S. Sian1, K. Vadhani1, A. Suman1, S. Rattigan2. Musgrove Park Hospital NHS Trust, Taunton. 1.SpR Ophthalmology, South West Peninsula Deanery, U.K Consultant Ophthalmologist, Musgrove Park Hospital, Taunton, U.K. Correspondence to Dr Indy Sian – Design courtesy of Mr M. Small.
INTRODUCTION
Recent joint guidelines released by the Royal Colleges of Ophthalmologists and Anaesthetists have given further instruction in the administration of ophthalmic anaesthesia.
Over the last 20 years, local anaesthesia (L.A) in cataract surgery has risen from 46% in 1991 to 75-86% in 1997 and has stabilised at 96% in [1]
Both Ophthalmic and Anaesthetic training has been influenced by the 2007 BOSU study by Eke et al and an Electronic Multi-centre audit of 55,567 operations in [3,4] They reported an increased frequency of serious complications with sharp needle L.A. blocks, moving practice towards subtenons and topical anaesthesia.
We have compared both of these techniques in a training setting.
DISCUSSION
No L.A. technique is free of risk. The 1996 National Survey of Local Anaesthesia for Ocular Surgery confirmed that serious systemic adverse events may occur with all types of LA, but are rare (3.4 per 10,000).[2]
The risk is not necessarily a direct consequence of a particular L.A. technique but relates to other factors including: pre-existing medical conditions, anxiety, ocular anatomy, pain and tension reaction to the operation.
Preoperatively, patients must be assessed for ability to tolerate instruments approaching the eye without anxiety or blepharospasm, even in those who had topical L.A. for their first eye.
Patient co-operation is of utmost importance when procedures are performed with topical (+/- intracameral) anaesthesia and as with all forms of anaesthesia, clear explanation of the procedure and that conversion to other forms of L.A. maybe required intraoperatively, must be given to the patient.
Sub-Tenons anaesthesia versus topical anaesthesia for cataract surgery has also been the subject of a Cochrane review. This study of 617 patients concluded that “sub-Tenon anaesthesia provides better pain relief than topical anaesthesia for cataract surgery”.[6] The Cochrane review of sub-Tenon’s versus topical anaesthesia reported that the serious operative complication of posterior capsular rupture with vitreous loss occurred twice as frequently in the topical group compared with the sub-Tenon’s group (4.3% versus 2.1%), (Total number of operations –742). [5]
When L.A. is contraindicated, for example patient refusal and local sepsis, then general anaesthetic or L.A. with sedation are alternatives.
METHOD
A total of 24 trainee ophthalmologist operating lists were prospectively reviewed, where both the surgeon and anaesthetist were constant. In total 89 second eye phacoemulsifications were conducted. A comparison of outcomes between sub-Tenons and topical anaesthesia were recorded as well as patient choice, complication rates, mean operating time, limiting factors and whether top up anaesthesia was required.
RESULTS
Of these procedures -
54/89 Topicals (with intracameral Lidocaine 1%) - 15 patients specifically requested, mean operating time = 16.4mins.
28/89 Sub-Tenons, mean operating time = 13.2mins. No top up.
7/89 General, mean operating time = 14.15mins.
Of the Topical anaesthesia
9 required top up anaesthesia (proxymetacaine 0.5% drops)
14 required conversion to sub-Tenons, (anxiety and excess movement) – each of these had topical anaesthesia for their first eye.
Complications
Nil in topical group
2 in subtenons group, 1 endophthalmitis (no surgical issues, no organisms grown after vitreous tap), 1 pc tear, no vitreous loss – IOL in the bag.
 Observations
Shallow anterior chambers and small axial lengths behaved better under subtenons anaesthesia.
Exclusion for topical anaesthesia was due to pre-operatively determined surgical complexity and lack of co-operation.
Draping and speculum insertion was consistently easier under subtenons anaesthesia.
Topical L.A. benefits included reduced chemosis and subconjunctival haemorrhage with reduced pooling, thus ensuring a good view.
Patient preference was highest for sub-Tenons anaesthesia.
Key points
Essentially, the choice of anaesthesia is dependent on surgeon preference and anaesthetist practice.
In a trainee setting subtenons anaesthesia is favourable over topical due to:
1. The presence of akinesia.
2. Reduced need for supplementation of anaesthesia.
3. Reduced mean operating times.
4. Increased ease of draping and speculum insertion.
5. Posterior capsular rupture is twice as likely to occur in topical L.A. [5]
References
1. Courtney P. The National Cataract Surgery Survey: I. method and descriptive features. Eye 1992;6(Pt.5):
2. Eke T, Thomson JR. The National Survey of local anaesthesia for ocular surgery. II. Safety profiles of local anaesthesia techniques. Eye 1999;13(Pt.2):
3. Eke T, Thomson JR. Serious complications of local anaesthesia for cataract surgery: a 1 year national survey in the United Kingdom. Br J Ophthalmol 2007;91(4):470-5.
4. El-Hindy N, Johnston RL, Jacycock P, et al. The Cataract National Dataset Electronic Multi-centre Audit of 55,567 Operations: anaesthetic techniques and complications.
5. Ezra DG, Allan BD. Topical anaesthesia alone versus topical anaesthesia with intracameral lidocaine for phacoemulsification. Cochrane Database Syst Rev 2007:18(3):CD
6. Frieman BJ, Friedberg MA. Globe perforation associated with subtenon’s anaesthesia. Am J Ophthalmol 2001;131(4):520-1.
7. Davison M, Padroni S, Bunce C, Rüschen H. SubTenon's anaesthesia versus topical anaesthesia for cataract surgery. Cochrane Database Syst Rev 2007;18(3):CD