Evaluation of Three Methods of Sensory Function Testing for the Assessment of Successful Maxillary Nerve Blockade in Horses

Maxillary nerve blocks (MNBs) commonly facilitate dental surgeries in standing horses. The goal of this prospective, blinded, cross-over design trial including 15 client-owned horses was to evaluate 3 methods of sensory function testing for confirming a successful MNB. Testing was performed bilaterally before sedation, 5 min after sedation, and 15 and 30 min after MNB with 0.5% bupivacaine and involved a needle prick dorsal to each naris, hemostat clamping of each nostril, and gingival algometry (measuring sensitivity to pain). Responses to stimulation were numerically scored and scores were summed up to a total score. Total score increases on the blocked side by ≥ 2 between baseline and 30 min Post MNB recordings signified a successful MNB. Sedation in the preceding 6 h, presence of sino-nasal disease, side of dental pathology, age, butorphanol administration, and detomidine dosing (µg/kg/min) throughout the tooth extraction procedure were recorded. In 73% of horses, MNB was successful. Sedation in the preceding 6 h (P = .732), age (P = .936), side of pathology (P = .516), and sino-nasal disease (P = .769) were not associated with total scores. Detomidine dosage and butorphanol use did not differ between horses in which the MNB was considered successful and for those in which it was not (P = .967 and P = .538, respectively). Scores obtained with gingival algometry were less closely associated with total scores (rho = .649) than those obtained with needle prick and nostril clamping (rho = .819 and .892, respectively). Therefore, needle prick and nostril clamping are considered the more reliable methods for use in clinical practice to determine the success of an MNB.

Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal

Feline skull anatomic variation is plain to see with casual observation. Obtaining an in-depth understanding of this anatomic variability is critical to performing safe and effective regional anesthesia for dental procedures and maxillofacial surgeries. Maxillofacial anatomic variability is proven to impact the placement and efficacy of nerve blocks in dogs and horses, but similar studies have not been performed in cats. This study's main objective was to evaluate the anatomy of the infraorbital foramen and canal in relation to regional anatomic landmarks in brachycephalic and mesaticephalic cats. Significant anatomic variability was identified, particularly among cats with brachycephalic skulls.

Clonidine as an Adjuvant to Bupivacaine for Suprazygomatic Maxillary Nerve Blocks in Cleft lip and Palate Repair: A Randomized, Prospective, Double-Blind Study

OBJECTIVES

Does clonidine, as adjuvant to bupivacaine for suprazygomatic maxillary nerve blocks, reduce emergence agitation in patients undergoing cleft lip and cleft palate surgery?

DESIGN

Randomized, controlled, and double-blind study.

SETTING

Guwahati Comprehensive Cleft Care Center, Guwahati (Assam, India).

PARTICIPANTS

A total of 124 patients; with a median age of 5 years in the clonidine group (CLG) and 7 years in the control group (CG), who underwent cleft lip or cleft palate surgery were included. Exclusion criteria included lack of consent from patients or their guardians, allergy to local anesthetics, coagulation disorders, local infection at the puncture site before performing the block, and language difficulties or cognitive disorders.

INTERVENTIONS

Patients were randomized into 2 groups to receive bilateral suprazygomatic maxillary nerve blocks with either a bupivacaine/clonidine mixture for the CLG or bupivacaine alone in the CG.

MAIN OUTCOME MEASURE

The primary end point was the incidence of emergence agitation.

RESULTS

There was a statistically significant difference in the incidence of emergence agitation (30.2% in the CG compared to 15.2% in the CLG; difference of incidences: 15%, 95% CI: 0.1-30.1). The percentage of patients requiring intraoperative Fentanyl was lower in the CLG (10.6% compared to 26.4%; difference of incidences: 15.8%, 95% CI: 1.8-29). No other differences were observed. Further research in a more typically aged children population undergoing cleft surgery is needed.

CONCLUSIONS

The use of clonidine as an adjuvant to bupivacaine in maxillary nerve block reduces the incidence of emergence agitation and intraoperative opioid consumption without hemodynamic or sedative side effects in patients undergoing cleft lip and palate surgery.

The effects of maxillary nerve block, ethmoidal nerve block and their combination on cardiopulmonary responses to nasal stimulation in anesthetized Beagle dogs

OBJECTIVE

To describe an approach for ethmoidal nerve block (E_BLOCK) and to compare the effects of a maxillary nerve block (M_BLOCK), E_BLOCK and their combination (M-E_BLOCK) on heart rate (HR), systolic (SAP), mean (MAP), diastolic (DAP) arterial pressures and respiratory rate (f_R) during nasal stimulation in dogs.

STUDY DESIGN

Prospective, blinded, randomized, crossover placebo-controlled study.

ANIMALS

Beagle dogs (five cadavers, nine live dogs), with a median (interquartile range) weight of 10.5 (10.3-11.0) kg.

METHODS

The accuracy of iohexol injections (each 1 mL) at the maxillary and ethmoidal foramina in cadavers was evaluated using computed tomography. Then, anesthetized dogs were administered four bilateral treatments separated by 1 week, saline or 2% lidocaine 1 mL per injection: injections of saline at the maxillary and ethmoidal foramina (Control), injections of lidocaine at the maxillary foramina and saline at the ethmoidal foramina (M_BLOCK), injections of saline at the maxillary foramina and lidocaine at the ethmoidal foramina (E_BLOCK) and injections of lidocaine at all foramina (M-E_BLOCK). The ventral nasal meatus was bilaterally stimulated using cotton swabs, and HR, SAP, MAP, DAP and f_R were continuously recorded. Values for each variable were compared before and after stimulation using Wilcoxon signed-rank test. Changes in variables among treatments were analyzed using Mann-Whitney U and Kruskal-Wallis tests (p ≤ 0.05).

RESULTS

Computed tomography revealed iohexol distribution around the openings of the target foramina in all cadavers. In living dogs, HR, SAP, MAP, DAP and f_R significantly increased after stimulation within each treatment (p < 0.03). Physiologic responses were significantly attenuated, but not absent, in the M-E_BLOCK [HR (p = 0.019), SAP, MAP, DAP and f_R (all p ≤ 0.001)] compared with those in the Control.

CONCLUSIONS AND CLINICAL RELEVANCE

Concurrent injections of lidocaine at the maxillary and ethmoidal foramina attenuated HR, arterial pressure and f_R responses to nasal stimulation in Beagle dogs.

Maxillary nerve block via the greater palatine canal: An old technique revisited

BACKGROUND

Maxillary nerve block through the greater palatine canal is rarely adopted by dental practitioners due to lack of experience in the technique at hand which may lead into several complications. Nevertheless, it is an excellent method to achieve profound anesthesia in the maxilla. This review focuses on the anatomy as well as the indications, contraindications, and complications associated with this technique.

MATERIALS AND METHODS

A literature search was performed using the scientific databases (PubMed and Google Scholar) for articles published up to December 2014 in English, using the key words "maxillary nerve block via the greater palatine canal." A total of 34 references met the inclusion criteria for this review and were selected.

CONCLUSION

Block of the maxillary nerve through the greater palatine canal is a useful technique providing profound anesthesia in the hemi-maxilla, if practiced properly.

Maxillary nerve block in management of maxillary bone fractures: Our experience

Background and Objectives:

The objective of this study is to evaluate the intraoral high tuberocity maxillary nerve block technique in zygoma and arch fracture reduction and fixation.

Study and Design:

This study was carried out at Arvind Multi-Specialty Hospital, Namakkal, Tamil Nadu on seven male patients with zygomatic bone and arch fracture.

Materials and Methods:

Intraoral high tuberocity maxillary nerve block administered in seven patients for management of isolated zygomatic bone and arch fracture. Lidocaine 2% measuring 4 mL with 1:80000 adrenaline anesthetic solutions was used to anesthetize maxillary nerve through a 3.2 cm length and 24G, needle. The following parameters were evaluated namely onset of anesthesia, nerve block duration, outcome of treatment and Patient's comfort.

Results:

The blocks were effective and patients were comfortable without pain during initial stage of surgery, but in latter stages two patients had mild to moderate pain. Duration of block varied from 60 to 90 min while onset varied from 3 to 10 min. There were vascular punctures in three patients, however, without hematoma.

Conclusions:

The maxillary nerve block is a good alternative option in selective cases of zygomatic bone fracture reduction.