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Global Translational Medicine Retrobulbar and sub-Tenon’s local anesthesia

drowsiness, and disorientation. Without IV sedation, study on cataract surgery, STB was associated with lower
introducing the needle around the eye, particularly in the pain scores. A separate study showed that although
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retrobulbar space, can be very uncomfortable and painful the need for resedation was lower with the retrobulbar
for the patient. Consequently, the results of both this and technique, the sub-Tenon’s group reported higher patient
our study suggest that comparisons between the efficacy satisfaction during surgery. 24
of retrobulbar injection and sub-Tenon’s technique may Although STB is known to be less effective in inducing
be influenced by the presence or absence of IV sedation. akinesia compared to other anesthetic techniques, this
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Similarly, Haider et al. compared topical, sub-Tenon’s, and did not impact surgeon performance in our study. An
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retrobulbar anesthesia for pars plana vitrectomy without experienced surgeon can stabilize the globe using probes
supplemental IV sedation, finding that topical anesthesia inserted into the trocars; however, this level of proficiency
was the least painful method. Although topical anesthesia may be challenging for less experienced trainees. In our
showed the lowest pain scores, retrobulbar anesthesia, with study, the factor most affecting surgeon satisfaction was
a mean perioperative pain score of 10.87 and a postoperative the level of perceived patient discomfort. This patient-
score of 13.73, was deemed the most convenient.
reported discomfort had a notable impact on surgeon
In our sub-Tenon’s group, we added a preliminary step satisfaction, underscoring the significance of patient
involving the subconjunctival injection. The resulting comfort in enhancing the overall surgical experience.
chemosis, although potentially disruptive to surgical One of the limitations of the current study is the selection
procedures, could be alleviated by conjunctival massage, bias resulting from the nonrandomized allocation of patients
which helped provide more reliable pain relief, particularly into groups. The unequal distribution of patients in the
during conjunctival manipulation at the start of surgery
and during trocar placement. This massage step could two study groups and the small sample size are significant
limitations. We also recognize that the lack of blinding
fill the time gap needed to achieve complete anesthetic could introduce bias, as evaluators may have known the
infiltration in the retrobulbar space, thus enhancing participants’ group assignments. In addition, the duration
patient comfort and allowing surgery to proceed sooner.
Alternatively, the time required for this massage could of the vitreoretinal surgeries per anesthesia group was not
offset the time saved between the retrobulbar block and recorded, and we did not exclude patients with diabetes or
sterile preparation. Therefore, it is unclear if sub-Tenon’s hypertension, which could influence perceived pain levels.
capsule anesthesia is faster than retrobulbar anesthesia. 5. Conclusion
However, like the sub-Tenon’s method, the retrobulbar
technique also requires massage to disperse the anesthesia Our results suggest that sub-Tenon’s anesthesia, combined
and prevent elevated intraocular pressure, especially when with subconjunctival injection, has similar efficacy to
hyaluronidase is not used. retrobulbar block in patients undergoing pars plana
vitrectomy in our cohort. Sub-Tenon’s anesthesia may
We conducted the STB using a sharp 27-gauge needle, serve as a suitable alternative to retrobulbar anesthesia
a common practice in clinical settings. However, some in some vitreoretinal surgery patients. Compared with
experts advocate using an angiocatheter due to its superior the retrobulbar technique, sub-Tenon’s anesthesia is less
safety profile, as its design may lower complication risks invasive, involves a shorter learning curve, and has a lower
during the procedure. Nevertheless, a significant drawback risk of complications and fewer preparatory steps.
of the angiocatheter is that it often requires a conjunctival
incision, which could extend the procedure duration and Acknowledgments
be uncomfortable for the patient.
None.
All our surgeries involved two painful steps—namely,
intraoperative indentation and laser photocoagulation— Funding
which were well tolerated by patients in both groups. None.
When ocular anesthesia faded during prolonged surgeries,
necessitating reinjection, the sub-Tenon’s technique was Conflict of interest
more feasible. In one study comparing sub-Tenon’s and
retrobulbar anesthesia for trabeculectomy in glaucoma The authors declare that they have no competing interests.
surgery, additional sedation was more frequently required
in the retrobulbar group, as was postoperative analgesia. Author contributions
This study also showed that the sub-Tenon’s method Conceptualization: Nazanin Ebrahimiadib, Fardin
required a lower volume of local anesthetic. In another Yousefshahi
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Volume 3 Issue 4 (2024) 6 doi: 10.36922/gtm.3900