Comparison of three regional anaesthetic techniques for infraorbital or maxillary nerve block in cats: a cadaveric study

Objectives The maxillary nerve courses very close to the globe, rendering cats – with their large eyes – at risk of globe penetration during infraorbital or maxillary nerve blocks. Therefore, the goals of the study were to compare the distribution and potential complications of three infraorbital or maxillary regional injection techniques. Methods Twenty-three bilateral maxillae of cat cadavers were used in a randomised blinded trial. Each maxilla was injected with a 0.2 ml 1:1 mixture of lidocaine 2% and a contrast medium by one of three injection techniques: infraorbital foramen (IOF; n = 14); infraorbital canal (IOC; n = 16); or maxillary foramen (MF; transpalpebral approach; n = 16) using a 25 G 1.6 cm needle. CT imaging of each cadaver head was performed before and after injections. A radiologist scored injectate distribution (none [0], mild [1], moderate [2], large [3]) in four locations: rostral, central and caudal IOC, and at the MF, for which the distribution side was also determined. Comparisons were performed with ordinal logistic mixed effects ( P <0.05). Results The median (range) total distribution score of the IOC and MF technique were significantly higher compared with the IOF technique (6.5 [4–12], 4 [2–8] and 0 [0–10], respectively). The total IOC score was also significantly higher compared with the MF technique. Injectate distribution at the MF was significantly more central following IOC injection compared with MF injection, which distributed centrolaterally. None of the techniques resulted in intraocular injection. Conclusions and relevance The IOC and MF techniques produced a satisfactory spread of the mixture that could result in effective maxillary anaesthesia in cats. Further studies are required to determine the effectiveness and safety of these techniques.

Opioid-free anaesthesia for the surgical correction of abnormalities associated with brachycephalic obstructive airway syndrome in five dogs

Opioid-free anaesthesia is currently becoming more popular in human medicine, as it provides multimodal analgesia, affecting multiple nociceptive pathways without the use of opioids, in order to minimise opioid-related side effects. This article presents the cases of five dogs undergoing surgical correction of abnormalities associated with brachycephalic obstructive airway syndrome, all of whom received opioid-free anaesthesia for surgery. All dogs received a bilateral maxillary nerve block with bupivacaine 0.5% and a combination of non-opioid analgesic drugs. Buprenorphine was allowed during the postoperative period, based on pain assessment. Three out of five dogs received buprenorphine 6–7 hours after the nerve block was performed. Opioid-free anaesthesia provided adequate conditions for surgery and no adverse effects were reported. Prospective controlled studies comparing opioid-free anaesthesia with opioid-based techniques are required to elucidate whether or not opioid-free anaesthesia confers objective advantages.

Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats

Regional nerve blocks have been shown to decrease general anesthetic drug requirements and improve pain management in patients undergoing surgery. Regional nerve blocks are used routinely in patients undergoing oral surgery, such as dental extractions. There is little published information regarding the efficacy of feline maxillary and infraorbital nerve blocks. The goal of the study was to compare injectate distributions of the infraorbital foramen and percutaneous maxillary nerve block techniques in feline cadavers using a combined dye and radiopaque contrast media solution to simulate an injection. There was no significant difference in length of stained nerve between the two different techniques. It was not necessary to advance the needle into the infraorbital canal to achieve effective staining of the maxillary nerve. There was no significant difference in injectate distribution between two different injectate volumes, 0.2 and 0.4 ml, indicating that the smaller volume injected at the infraorbital foramen resulted in adequate nerve staining.

A study of greater palatine foramen and its importance in the application of maxillary nerve block in South Indian Population

Introduction: The greater palatine foramen (GPF) is located in the posterior part of the hard palate between the articulations of hard palate with the maxilla. GPF continues posteriorly and upwards as greater palatine canal (GPC) which opens in to the inferior wall of pterygopalatine fossa. Exiting the foramen rotendum, maxillary nerve enters the pterygopalatine fossa where it can be blocked. The intraoral route of GPF approach can be preferred for maxillary nerve block because of its low incidence of complications and high success rate. For achieving a painless intra operative period in procedures involving the maxillary region and for tooth extraction achieving a perfect maxillary nerve block is of at most importance. Our present study is aimed at correctly locating the position of GPF, its shape and patency in south Indian population which will be helpful for the intra oral approach of maxillary nerve block through the GPF Materials and Methods: The study was conducted in 30 dry adult skull bones of both sex. The molar relation, shape and the patency of the GPF were observed, the readings were obtained, statistically analyzed and compared with other studies. Results: In our observation on both side of skull, it was noted that GPF was located opposite to the 3rd molar in 90% of cases. Oval shaped GPF is most commonly found in our study which accounts to 53.35% and the overall patency rate for GPF was 95% in our study. Conclusion: Analysis and comparison of data has proven that the position, shape and patency of GPF may vary according to different races. This study has also confirmed that the maxillary nerve block via GPF is relatively safe and easier due to the consistency of the position, shape and the patency of the GPF in south Indian population. KEY WORDS: Greater palatine foramen, maxillary nerve block, regional blocks, Greater palatine canal, pterygopalatine fossa, Maxillary nerve.

Compuflo®-Assisted Performance of a Maxillary Nerve Block in Horses: Evaluation of a Novel Technology as a Training Tool and Guide in Clinical Practice

The CompuFlo®-device provides value as training tool for veterinary professionals learning to execute maxillary nerve blocks. Further research is warranted to determine its true benefits in equine dentistry practice.