Healio
Healio
February 01, 2016
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Sub-Tenon’s cannula may be similar to sharp retrobulbar needle for vitreoretinal surgery anesthesia

The use of a sub-Tenon’s cannula may be comparable to a sharp retrobulbar needle for local operative anesthesia before vitreoretinal surgeries, according to a study.

Perspective from Daniel F. Kiernan, MD

The retrospective comparative study reviewed 1,711 vitreoretinal surgeries that received local anesthesia, in which 940 cases were performed with a blunt sub-Tenon’s cannula and 771 cases were performed with a sharp retrobulbar needle. In total, 99% of cases in each surgical group were completed.

There was a surgeon preference for a sharp retrobulbar needle over a blunt sub-Tenon’s cannula in eyes that had a scleral buckle present and in eyes undergoing scleral buckle placement.

“We surmise this bias reflects surgeons’ concerns for conjunctival scarring with resultant difficulty in passing the blunt cannula into the sub-Tenon’s space and concern for postoperative scleral buckle exposure at the conjunctival incision needed to pass the blunt cannula,” the study authors said.

Conversion from local anesthesia to general endotracheal anesthesia was required in nine procedures using a sub-Tenon’s cannula and 12 procedures using a retrobulbar needle.

There were no vision-threatening complications in either group.

“Since we observed no blinding complications of globe perforation, retrobulbar hemorrhage or brain stem anesthesia in either group during our study, we cannot claim one technique is safer than another,” the authors said. – by Kristie L. Kahl

Disclosure: The authors report no relevant financial disclosures.

Perspective

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Daniel F. Kiernan, MD
Daniel F. Kiernan, MD

Reichstein and colleagues present a large retrospective comparison of the safety of, and to some extent the decision-making behind, use of a blunt sub-Tenon’s cannula to a sharp retrobulbar needle for applying local anesthesia during vitreoretinal surgery. The take-home points are that both procedures appeared equally safe in the hands of experienced surgeons, although there was a preference for using a retrobulbar needle either in the presence of a pre-existing scleral buckle or if scleral buckle surgery was planned. In addition, the authors noted that the sub-Tenon’s blunt cannula “adds only minutes to each case … and never produced subconjunctival chemosis severe enough [to negatively affect the case].“ Although not addressed in the article, an important clinical implication is that use of a blunt cannula may offer surgeons a more controlled method of local anesthesia application in patients who are taking aspirin or anticoagulant medication, and thus may reduce serious ocular risks, including retrobulbar hemorrhage, eyelid bruising and severe subconjunctival hemorrhage and chemosis.

  • Reference:
  • Guise P. Local Reg Anesth. 2012;doi:10.2147/LRA.S16314.
Daniel F. Kiernan, MD
Ophthalmic Consultants of Long Island
New York
Disclosures: Kiernan reports no relevant financial disclosures.
Sources/Disclosures

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Source:

Reichstein DA, et al. Ophthalmic Surg Lasers Imaging Retina. 2015;doi:10.3928/23258160-20151214-08.