Three dimensional MRI study: Safety of short versus long needle peribulbar anesthesia

Abstract

There is a larger structure-free space at a depth of 12.5 mm than at 25 mm. Therefore, the inference is that a needle inserted in the infero-temporal zone to a depth of 12.5 mm is less likely to injure the eyeball or extra-ocular muscles than one advanced to 25 mm.

Predicting Lens Diameter: Ocular Biometry With High-Resolution MRI

“…Patients' data sets that showed signs of peribulbar anesthesia were excluded from the final analysis. However, ElKhamary et al 24 observed the effect of different peribulbar anaesthesia techniques, and they did not observe any morphologic changes of the globe in their MRIs, but it has to be mentioned that their focus of the study was the peribulbar region.…”

Comparison of Two Needle Lengths in Regional Ophthalmic Anesthesia in The Medial Canthus Approach: A Prospective study

“…The risk of injury by long needles increases particularly in patients with shallow orbits [4]. The use of needles with shorter lengths (12 to 15 mm) has been reported in the literature [9][10][11][12][13][14][15][16][17][18], with varying results of efficacy and safety compared with the standard PBA technique. The present study thus aimed to compare the efficacy and safety of using a 12mm needle to the standard 25mm needle in performing PBA at the medial canthus in cataract surgery.…”

“…The injection of a small volume of local anesthetic (5-6.5 ml) was demonstrated to surround the eye globe and produce analgesia. The higher need for anesthetic supplementation in PBA with long needles may be explained by the potential passing of the needle into the inferior orbital floor which causes a reduction of the spread of local anesthetic around the eye globe [9,19]. The rate of requiring anesthetic supplementation while performing PBA with short needles varied widely among the studies.…”

“…Scott et al [19] showed that a 16mm needle would reach up to the orbital equator and would not pass beyond it unless forcibly pushed. Besides, ElKhamary and Riad [9] assessed the anatomy of orbital structures at 12.5mm and 25mm depths in 50 subjects using three-dimensional magnetic resonance imaging. They concluded that there is a larger structurefree space at a depth of 12.5mm than at 25mm.…”

Computed tomography scan measurements of the globe and orbit to assess the risks of traumatic complications from medial peribulbar anaesthesia

“…MRI has been used to assess the risks of peribulbar anaesthesia to extra ocular muscles in the infero-temporal quadrant (myopic patients were excluded) [ 13 ].…”