Efficacy and Safety of a Novel Blunt Cannula Trans-Sub-Tenon's Retrobulbar Block for Vitreoretinal Surgery.

Purpose: To evaluate a novel trans-sub-Tenon's retrobulbar block (TSTRB) compared to sub-Tenon's block (STB) and peribulbar block (PBB) anesthesia for vitreoretinal surgery.

Methods: This study was a prospective evaluation of cases undergoing TSTRB, STB, or PBB. The Kallio scale and Brahma scales were used to score hemorrhage and extraocular motility, respectively. Pain was documented on a visual analog score graded (1-10) at induction, intraoperatively, and postoperatively, any confounding variables were noted.

Results: Seventy eyes have been used in this analysis, of which TSTRB was used in 37% ( = 26), PBB in 34% ( = 24), and STB in 29% ( = 20). Postoperative analgesia was required by 10% ( = 2) of STB and 8% ( = 2) of PBB; none of the TSTRB cases required analgesia ( = 0.003). The mean volume required with each technique was as follows: TSTRB, 4.8 ml; STB, 5.3 ml; and PBB, 10.4 ml ( = 0.030). The volume of anesthesia was correlated with the level of proptosis and even more important affected the ease of surgery most ( = 0.005). Akinesia was greatest with TSTRB > PBB > STB ( = 0.040). There were no complications such as brainstem anesthesia, globe perforation, or retrobulbar hemorrhage.

Conclusion: Intentionally extending a STB into the retrobulbar space, via a TSTRB fenestration utilizes a familiar skill set. TSTRB produced the best levels of reduced kinesia during surgery and increased duration of postoperative analgesia. The technique uses a small-volume anesthesia.