Sub-Tenon's anaesthesia: an efficient and safe technique

Abstract

Aim: To evaluate sub-Tenon's anaesthesia as an alternative to peribulbar anaesthesia.

Methods: 109 consecutive patients listed for various eye operations (including cataract, trabeculectomy, and vitrectomy) under peribulbar anaesthesia were operated on under sub-Tenon's anaesthesia instead. After topical anaesthesia a buttonhole was fashioned through the conjunctiva and Tenon's capsule 10 mm posterior to the limbus. 1.5 ml of lignocaine 2% was then delivered to the posterior sub-Tenon's space using a blunt cannula. The surgical procedure was performed immediately after the completion of the anaesthetic procedure. Chemosis, conjunctival haemorrhage, degree of akinesia, and pain scoring were analysed.

Results: There were no anaesthesia related complications. The administration of the block was painless for 99.1% of the patients. In all, 97.3% reported no pain during surgery. There was no akinesia when assessed just after the completion of the block and akinesia was limited when assessed after surgery. Chemosis and conjunctival haemorrhage were frequent but caused no intraoperative problems.

Conclusion: Sub-Tenon's anaesthesia is an efficient and safe anaesthetic technique. It is a good alternative to peribulbar anaesthesia.

Figures

Figure 1

Pain scoring for the delivery of the sub-Tenon's anaesthetic procedure (0 = no pain, no sensation; 1 = slight `sensation' or discomfort but no pain; 2 = slight pain; 3 = moderate pain; 4 = intense pain).

Figure 2

Pain scoring recorded for the operative procedure (0 = no pain, no sensation; 1 = slight `sensation' or discomfort but no pain; 2 = slight pain; 3 = moderate pain; 4 = intense pain).

Figure 3

Degree of akinesia just after sub-Tenon's anaesthesia (0 = complete movement remaining; 1 = moderate movement, 2 = slight movement, and 3 = no movement).

Figure 4

Degree of akinesia at the end of surgery (0 = complete movement remaining, 1 = moderate movement, 2 = slight movement, and 3 = no movement).

Figure 5

Chemosis (0 = no chemosis; + = chemosis involving one quadrant; ++ = chemosis involving two quadrants; +++ = chemosis involving three or four quadrants).

Figure 6

Conjunctival haemorrhage (0 = no haemorrhage; + = haemorrhage involving one quadrant; ++ = haemorrhage involving two quadrants; +++ = haemorrhage involving three or four quadrants).