Objective: In view of the discomfort caused by sub-Tenon's Block (STB) during vitrectomy, our study aimed to identify a new method of anesthesia that can reduce the pain caused by STB.
Methods: Sixty patients with vitreous opacity, diabetic retinopathy, complicated retinal detachment or lens dislocated into vitreous cavity were selected. Patients were randomly divided in to experimental group and control group (n=30). No significant differences in background information were found between two groups. All patients were treated with vitrectomy. STB was performed for patients in control group, while expansive STB was used in experimental group. Anesthesia and surgery related factors, degree of pain, basic vital signs, anesthesia complications and analgesia grade were recorded and compared between two groups.
Results: Operation time of anesthesia and onset time of anesthesia were significantly shorter in experimental group than in control group (p<0.01), but no significant differences in operation time of surgery, duration of anesthesia and dose of anaesthetic drugs were found between two group. The degree of pain caused by expansive STB was significantly lower than that of STB (p<0.01). Normal heart rate, respiratory rate and blood pressure were observed in both groups of patients during the whole procedure of surgery. No significant differences in anesthesia complications were found between two groups. The analgesic effect of expansive STB was better than that of STB. In addition, no other complications caused by this method were observed during this study.
Conclusion: Compared with STB, expansive STB can shorten the operation time of anesthesia and onset time of anesthesia, and reduce the degree of pain.