Severe orbital hematoma with third eyelid swelling and prolapse following a blind maxillary nerve block in a horse.

A 20-year-old quarter horse gelding was presented for routine dental examination. Periodontal disease and luxation of tooth 108 was diagnosed and oral extraction was planned. After an unsuccessful blind maxillary nerve block, it was elected to perform the procedure under total intravenous anesthesia. Following recovery, a focal superficial corneal ulcer, severe retrobulbar swelling, mild exophthalmos, and marked swelling and prolapse of the third eyelid (nictitating membrane) were observed. Clinical signs persisted beyond 48 h despite the use of systemic anti-inflammatories and topical ocular anti-inflammatories and antibiotics. A temporary tarsorrhaphy was subsequently done at 48 h and the horse was discharged after 5 d of hospitalization and regression of clinical signs. Although it is very useful for easing dental extractions, the blind maxillary nerve block is associated with potential complications due to inadvertent vascular puncture. This case report describes a rare complication of prolapse of the third eyelid in a horse after a maxillary nerve block and successful treatment with a temporary tarsorrhaphy. Key clinical message: This case report explains how nictitating membrane swelling and prolapse can occur following a blind maxillary nerve block in the horse and describes treatment with a temporary tarsorrhaphy.

Hématome orbitaire sévère avec gonflement de la troisième paupière et prolapsus à la suite d'un bloc du nerf maxillaire à l'aveugle chez un cheval. Un hongre quarter horse de 20 ans a été présenté pour un examen dentaire de routine. Une maladie parodontale et une luxation de la dent 108 ont été diagnostiquées et une extraction orale a été planifiée. Après l'échec d'un bloc du nerf maxillaire à l'aveugle, il a été décidé d'effectuer la procédure sous anesthésie intraveineuse. Après la guérison, un ulcère cornéen superficiel focal, un gonflement rétrobulbaire sévère, une légère exophtalmie ainsi qu'un gonflement et un prolapsus marqués de la troisième paupière (membrane nictitante) ont été observés. Les signes cliniques ont persisté au-delà de 48 heures malgré l'utilisation d'anti-inflammatoires systémiques et d'anti-inflammatoires oculaires topiques et d'antibiotiques. Une tarsorraphie temporaire a ensuite été réalisée à 48 heures et le cheval est sorti après 5 jours d'hospitalisation et de régression des signes cliniques. Bien qu'il soit très utile pour faciliter les extractions dentaires, le bloc du nerf maxillaire à l'aveugle est associé à des complications potentielles dues à une ponction vasculaire involontaire. Ce rapport de cas décrit une complication rare de prolapsus de la troisième paupière chez un cheval après un bloc nerveux maxillaire et un traitement réussi par tarsorraphie temporaire.Message clinique clé:Ce rapport de cas explique comment un gonflement et un prolapsus de la membrane nictitante peuvent survenir à la suite d'un bloc du nerf maxillaire à l'aveugle chez le cheval et décrit le traitement par tarsorraphie temporaire.(Traduit par Dr Serge Messier).

Chronic Constriction Injury of the Distal Infraorbital Nerve (DIoN-CCI) in Mice to Study Trigeminal Neuropathic Pain.

Animal models remain necessary tools to study neuropathic pain. This manuscript describes the distal infraorbital nerve chronic constriction injury (DIoN-CCI) model to study trigeminal neuropathic pain in mice. This includes the surgical procedures to perform the chronic constriction injury and the postoperative behavioral tests to evaluate the changes in spontaneous and evoked behavior that are signs of ongoing pain and mechanical allodynia. The methods and behavioral readouts are similar to the infraorbital nerve chronic constriction injury (IoN-CCI) model in rats. However, important changes are necessary for the adaptation of the IoN-CCI model to mice. First, the intra-orbital approach is replaced by a more rostral approach with an incision between the eye and the whisker pad. The IoN is thus ligated distally outside the orbital cavity. Secondly, due to the higher locomotor activity in mice, allowing rats to move freely in small cages is replaced by placing mice in custom-designed and constructed restraining devices. After DIoN ligation, mice exhibit changes in spontaneous behavior and in response to von Frey hair stimulation that are similar to those in IoN-CCI rats, i.e., increased directed face grooming and hyperresponsiveness to von Frey hair stimulation of the IoN territory.

Ultrasound-Guided Suprazygomatic Maxillary Nerve Block Is Effective in Reducing Postoperative Opioid Use Following Bimaxillary Osteotomy.

BACKGROUND: Ultrasound-guided maxillary nerve block has recently been described, though its impact upon bimaxillary osteotomy has not been formally investigated. PURPOSE: The present study was carried out to determine whether the addition of ultrasound-guided maxillary nerve block in subjects undergoing bimaxillary osteotomy reduces opioid use. STUDY DESIGN, SETTING, SAMPLE: A randomized clinical trial was carried out in adults undergoing bimaxillary osteotomy between April 2019 and January 2020 at Teknon Medical Center (Barcelona, Spain). PREDICTOR VARIABLE: The predictor variable was the treatment technique used (maxillary nerve block or no block). The subjects were randomized to either receive (test group) or not receive (control group) bilateral ultrasound-guided suprazygomatic maxillary nerve block (5 ml of 0.37% ropivacaine) before surgery. MAIN OUTCOME VARIABLE(S): The primary outcome variable was the intravenous methadone requirements in the first two postoperative hours. The secondary outcome variables were postoperative pain, rescue subcutaneous methadone, intravenous remifentanil used intraoperatively, the incidence of postoperative nausea-vomiting, and complications derived from maxillary nerve block. COVARIATES: Subject age, sex, weight, height, and anesthetic risk, and the duration of surgery were recorded. ANALYSES: Descriptive and inferential analyses were performed using the χ2 test and Mann-Whitney U test. Statistical significance was considered for P < .05. RESULTS: The baseline sample consisted of 68 subjects scheduled for bimaxillary osteotomy. The follow-up sample comprised 60 subjects: 30 in the control group (10 females and 20 males, aged 34.0 ± 10.2 years) and 30 in the test group (13 females and 17 males, aged 29.8 ± 10.8 years). The subjects who received maxillary nerve block showed less intravenous methadone use in the first 2 hours postsurgery (median 2.0 mg control group vs 0 mg test group; P < .001), lower pain levels at any time during the first 18 hours postsurgery (median visual analog score 4 control group vs 2 test group; P < .001), and a lesser percentage required methadone (33.3% control group vs 0% test group; P < .01) at 4-18 hours postsurgery. CONCLUSION AND RELEVANCE: The results obtained suggest that ultrasound-guided maxillary nerve block is a promising anesthetic technique capable of reducing intraoperative and postoperative opioid use, with greater patient comfort in bimaxillary osteotomy.

Unreported variant foramen of the frontal bone: the latero-orbital foramen.

Variant foramina of the skull can lead to misdiagnosis on medical imaging and potentially, intraoperative complications if not appreciated. Here, we report an unusual foramen found superior to the frontozygomatic suture. The foramen was located on the left side at the superolateral rim of the orbit, 2.36 cm inferolateral to the supraorbital foramen. It was positioned 2.5 mm superior to the frontozygomatic suture. The foramen had a length of 3.1 mm and a width of 1.3 mm. The internal opening of the foramen was located 1.45 cm superolateral to the zygomaticotemporal foramen. We suggest that this foramen is a pathway for either a branch of the zygomatic nerve or lacrimal nerve and/or their vascular bundles. Although the prevalence of such a finding cannot be confirmed, such a case is of archival value as a comparison for future similar cases.

Evaluation of the addition of adrenaline in a bilateral maxillary nerve block to reduce hemorrhage in dogs undergoing sharp staphylectomy for brachycephalic obstructive airway syndrome. A prospective, randomized study.

OBJECTIVE: To assess the use of adrenaline (0.00198%) in a bilateral maxillary nerve block to reduce intraoperative hemorrhage in dogs undergoing staphylectomy for the treatment of brachycephalic obstructive airway syndrome (BOAS). STUDY DESIGN: Prospective, randomized, double-blinded controlled study. SAMPLE POPULATION: A total of 32 client owned, clinically affected dogs undergoing a cut and sew sharp staphylectomy for treatment of BOAS. A total of 16 dogs randomly assigned to adrenaline (A) group and 16 to no-adrenaline (NA) group. METHODS: A bilateral maxillary nerve block was performed in all dogs prior to staphylectomy using lidocaine alone (group NA) or a combination of lidocaine and adrenaline (group A). Total hemorrhage was measured by weighing cotton-tipped applicators and swabs used on precision scales. In addition, a semi-quantitative hemorrhage score (1-5) was determined. Dogs were monitored for intraoperative hemodynamic stability during the procedure. RESULTS: Total hemorrhage was significantly (p = .013) lower in group A compared with group NA. The median semi-quantitative hemorrhage score was significantly lower for group A (p = .029) compared with group NA. No significant adverse effects were noted due to adrenaline usage. CONCLUSION: This study demonstrated that the use of adrenaline in a bilateral maxillary nerve block results in significantly lower intraoperative hemorrhage during cut and sew sharp staphylectomy and appeared safe to use. CLINICAL SIGNIFICANCE: Potential clinical advantages include improved visualization, prevention of unnecessary blood loss and reduction in risk of blood aspiration.

Investigation of a maxillary nerve block technique in guinea pigs (Cavia porcellus): A cadaveric study comparing two injectate volumes.

OBJECTIVE: To investigate and describe an extraoral approach to perform a maxillary nerve block in guinea pigs. STUDY DESIGN: Prospective, randomized, blinded, descriptive, cadaveric study. ANIMALS: A total of 14 adult guinea pig cadavers. METHODS: Two cadavers were used for anatomic dissection and determination of maxillary nerve block approach. A maxillary nerve block via infraorbital approach was then performed in 12 cadavers. A low volume (0.1 mL) or high volume (0.2 mL) of diluted methylene blue injectate was randomly assigned to the right or left side, with the other volume used for the contralateral side. The maxillary nerve was dissected after each injection by an investigator blinded to injectate volume. The region of dye distribution was identified, and the degree of staining assigned an accuracy score (0-2). Nerve coverage was considered adequate if ≥6 mm of circumferential staining was present. RESULTS: Accuracy evaluation indicated successful dye deposition in 10/12 [2 (0-2), median (range)] injections in the low volume group and 8/12 [2 (1-2)] injections in the high volume group. The majority (79.2%) of injections resulted in adequate nerve staining. There were no statistically significant differences between injectate volumes for accuracy (p = 0.64) or adequacy (p > 0.99) of staining. CONCLUSIONS: The infraorbital approach is a simple and practical method for maxillary nerve blockade in guinea pigs. An injectate volume of 0.1 mL results in adequate maxillary nerve coverage; however, additional studies are needed to assess the efficacy in clinical use.

Risk Factors for Recurrence After Radiofrequency Surgery of the V2 Branch of the Trigeminal Nerve.

BACKGROUND: The factors influencing relapse after radiofrequency operation of the V2 branch of the trigeminal neuralgia are yet to be identified. OBJECTIVES: The risk factors affecting recurrence after radiofrequency operation of the V2 branch of the trigeminal neuralgia were analyzed, and a curative effect prediction model was constructed. STUDY DESIGN: A retrospective study. SETTING: This study was conducted at the Affiliated Hospital of Jiaxing University, People's Republic of China. METHODS: The records of patients with maxillary nerve pain in the V2 branch of the trigeminal nerve who underwent computed tomography-guided foramen rotundum radiofrequency treatment at the Pain Department of the Affiliated Hospital of Jiaxing College from April 2014 through December 2020 were collected and randomly divided into training (n = 137) and test (n = 59) groups at a 7:3 ratio. The outcome variable was whether or not recurrence was observed 2 years postsurgery. Independent predictors were screened by LASSO (least absolute shrinkage and selection operator) regression analysis. Based on these findings, a nomogram prediction model was explored further and developed using multifactor logistic regression analysis. Also, the feasibility of the nomogram prediction model for recurrence after radiofrequency was assessed using a validation group. Finally, the discriminatory power, accuracy, and clinical utility of the prediction model were evaluated using the receiver operating characteristic (ROC), area under the curve (AUC), calibration curve, and decision curve analysis (DCA), respectively. RESULTS: LASSO regression, combined with multifactorial logistic regression analysis, identified factors such as age, duration, branches, and numbness that influence V2 trigeminal nerve pain recurrence in patients 2 years post-radiofrequency surgery (P < 0.05). The above variables were used to construct the nomogram prediction models. The AUC of the nomogram prediction model predicted that the recurrence post V2 radiofrequency was 0.726 in the training group and 0.611 in the test group. The DCA showed that the columnar plot prediction model predicted the risk of recurrence post-radiofrequency of the V2 branch of the trigeminal nerve had a threshold probability of 0 - 0.9. LIMITATIONS: This was a single-center study. CONCLUSION: A highly accurate nomogram prediction model (predictor variables include age, duration, branches, and numbness) was developed to improve the early identification and screening of patients at high risk of recurrence after V2 trigeminal nerve radiofrequency surgery. KEY WORDS: Trigeminal neuralgia, maxillary neuralgia, radiofrequency, risk factors, prediction model.

Ultrasound-Guided Maxillary Nerve Block and Superficial Cervical Plexus Block During Surgery for Maxillary Malignancy: A Case Report.

We report a case of ultrasound-guided craniocervical nerve blocks performed with ropivacaine for perioperative local/regional anesthesia in a patient who underwent right partial maxillary resection and neck dissection under general anesthesia. The patient was an 85-year-old woman with multiple medical comorbidities in whom analgesia using nonsteroidal anti-inflammatory drugs and opioids was expected to increase the risk of postoperative complications. Bilateral ultrasound-guided maxillary (V2) nerve blocks and a right superficial cervical plexus block were performed, which provided adequate perioperative anesthesia and avoided postoperative complications. The use of ultrasound-guided craniocervical nerve blocks with ropivacaine can be an effective approach for providing prolonged perioperative local anesthesia and analgesia, minimizing the need for other potentially problematic analgesics.

Utility of Regional Maxillary Nerve Blocks in Improving Cleft Palate Postoperative Outcomes.

BACKGROUND: Palatoplasty procedures used to repair cleft palates are commonly associated with limiting postoperative pain. Regional anesthetic blocks have been utilized to improve pain outcomes and decrease opioid intake, yet additional data is needed to fully explore its utility in this setting. OBJECTIVE: To explore whether ultrasound-guided suprazygomatic maxillary blocks (SMB) improve postoperative pain, postoperative opioid use, time to oral feeding, and length of stay compared with a palatal field block in cleft palate repair. METHODS: In this retrospective chart review, 47 patients aged 9 to 25 months who underwent cleft palate repair between 2013 and 2020 were allocated into 2 groups: a control group where patients received only palatal local anesthetic in a field block fashion (N=29), and Maxillary block group who received ultrasound-guided SMB (N=18). Patients were matched by age and cleft Veau type. The primary outcomes were total postoperative morphine equivalent consumption, average pain scores, length of stay, and time to first oral feed. RESULTS: Comparing field block versus SMB groups, there was not a statistical difference in the overall dose of postoperative morphine equivalent opioid administration (11.71 vs. 13.36 mg; P =0.483), average pain scores (5.78 vs. 5.27; P =0.194), time to first oral feed [17.21 vs. 14.48 h; P =0.407, 95% CI: (-3.85, 9.32)] or length of stay ( P =0.292). CONCLUSION: The use of SMBs did not demonstrate a difference in the postoperative outcomes evaluated by this study. Further study is needed to define its utility in cleft palate repair.

Maxillary Nerve as Landmark for Exposure of the Internal Maxillary Artery in Extracranial-Intracranial Bypass Surgery.

OBJECTIVE: To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery. METHODS: To explore the positional relationship between the IMA and the maxillary nerve and pterygomaxillary fissure, 11 formalin-fixed cadaveric specimens were dissected. Three bone windows of the middle fossa were created for further analysis. Then the IMA length that could be pulled up above the middle fossa was measured after different degrees of removal of bony structure. The IMA branches under each bone window were also explored in detail. RESULTS: The top of the pterygomaxillary fissure was located 11.50 mm anterolateral to the foramen rotundum. The IMA could be identified just inferior to the infratemporal segment maxillary nerve in all specimens. After drilling of the first bone window, the IMA length that could be pulled above the middle fossa bone was 6.85 mm. After drilling of the second bone window and further mobilization, the IMA length that could be harvested was significantly longer (9.04 mm vs. 6.85 mm; P < 0.001). Removal of the third bone window did not significantly improve the IMA length that could be harvested. CONCLUSIONS: The maxillary nerve could be used as a reliable landmark for the exposure of the IMA in the pterygopalatine fossa. With our technique, the IMA could be easily exposed and sufficiently dissected without zygomatic osteotomy and extensive middle fossa floor removal.

Comparison of the feasibility and safety of infrazygomatic and suprazygomatic approaches to pterygopalatine fossa using virtual reality.

BACKGROUND: Injections of local anesthetics into pterygopalatine fossa gained popularity for treating acute and chronic facial pain and headaches. Injury of maxillary artery during pterygopalatine fossa injection can result in pseudoaneurysm formation or acute bleeding. We aimed to identify the optimal approach into pterygopalatine fossa by comparing feasibility and safety of suprazygomatic and two infrazygomatic approaches. METHODS: We analyzed 100 diagnostic CT angiographies of cerebral arteries using 3D virtual reality. Each approach was determined as a target point in pterygomaxillary fissure and an array of outermost edges trajectories leading to it. The primary outcomes were feasibility and safety for each approach. The secondary outcome was the determination of maxillary artery position for each approach to identify the safest needle entry point. RESULTS: Suprazygomatic approach was feasible in 96.5% of cases, while both infrazygomatic approaches were feasible in all cases. Suprazygomatic approach proved safe in all cases, posterior infrazygomatic in 73.5%, and anterior infrazygomatic in 38%. The risk of maxillary artery puncture in anterior infrazygomatic approach was 14.7%±26.4% compared to 7.5%±17.2%. in posterior infrazygomatic with the safest needle entry point in the upper-lateral quadrant in both approaches. CONCLUSION: The suprazygomatic approach proved to be the safest, however not always feasible. The posterior infrazygomatic approach was always feasible and predominantly safe if the needle entry point was just anterior to the condylar process. The anterior infrazygomatic approach was always feasible, however least safe even with an optimal needle entry point just anterior to the coronoid process.

Changing the topographical anatomy among the maxilla, palatine bone, and greater palatine nerve: a histological study using human fetuses.

PURPOSE: The palatine bone (PAL) rides over the maxilla (MX) without an end-to-end suture in the bony palate of fetuses. However, changes in the topographical relationship among bones was unknown at and along the pterygopalatomaxillary suture, including the palatine canals. METHODS: Using sagittal, frontal, and horizontal histological sections of the head from 15 midterm fetuses to 12 near-term fetuses, we depicted the changes in the topographical anatomy of the MX, PAL, and greater palatine nerve (GPN). RESULTS: In the bony greater palatine canal of these fetuses, the medial and posterior walls facing the GPN were consistently made up of the PAL. At midterm, the entire course of the GPN was embedded in the PAL (six fetuses), or the MX contributed to the lateral wall of the nerve canal (nine). At near-term, the anterior and lateral walls showed individual variations: an MX in the anterior and lateral walls (three fetuses), an anterior MX and a lateral PAL (five), an anterior PAL and a lateral MX (two), and a PAL surrounding the GPN (four). CONCLUSION: These increasing variations suggested that the pterygopalatomaxillary suture was actually growing and that the PAL transiently expanded anteriorly and/or laterally to push the MX in fetuses. The "usual" morphology in which the GPN is sandwiched by the MX and PAL is likely established after birth, possibly during adolescence. The driving force of this change may not be produced by the masticatory apparatus. Rather, it might be triggered by the growing maxillary sinus.

Extracranial schwannoma of the maxillary nerve misdiagnosed as trigeminal neuralgia in an elderly patient with schizophrenia - A diagnostic dilemma.

The present paper discusses the diagnostic challenges we faced in a 60-year-old woman with a history of schizophrenia, presenting with left unilateral facial pain for the past three months. Based on the elaborate clinical examination and diagnostic nerve blocks, the patient was diagnosed with trigeminal neuralgia (TN) and non-surgical therapy commenced. Further investigations with magnetic resonance imaging (MRI) and ultrasound-guided fine needle aspiration cytology (FNAC) revealed the presence of an extracranial schwannoma involving a branch of the maxillary nerve. The patient was symptomatically relieved after surgical excision of the benign tumor under general anesthesia. Hence, we emphasize the need for special care and attention in psychiatric patients presenting with orofacial pain.

Herniation of Fat from the Infraorbital Canal into the Maxillary Sinus: A Cadaveric Case Report.

The infraorbital canal serves as a conduit for the infraorbital nerve. The canal travels anteriorly beneath the globe where it emerges onto the face at the infraorbital foramen. Variations in the morphology of the infraorbital canal have been reported and classified based on their relationship with the maxillary sinus. Similarly to the other orbital fat compartments, fat in the infraorbital canal serves as protection to the structures it surrounds. Generally, the orbital fat compartments do not undergo hypertrophy without a pathological etiology, therefore, it has been hypothesized that herniations of orbital fat are a result of age-related bony changes in the orbit. The inferior orbital rim, in particular, acts to support structures of the orbit including the fat compartments, ligaments, and muscles. The most commonly reported herniations are those of the infraorbital fat pads, which either prolapse into the inferior orbital fissure or move anteriorly to give patients the appearance of a bulging lower eyelid. Additionally, there are reports of traumatic injuries that result in herniation of the buccal fat pad into the maxillary sinus. Herein, we report a rare case of a herniation of the infraorbital canal fat into the maxillary sinus and review the salient literature.

Cardiovascular Responses to Nasal Stimulation Under Ethmoidal-Maxillary Nerve Block and Lidocaine Gel in Anesthetized Beagles.

This study aimed to compare the effect of ethmoidal-maxillary nerve block (EMBLOCK) and topical application of 2% lidocaine gel (LGEL) on cardiovascular variables (heart rate and arterial blood pressure) during mechanical stimulation of the nasal cavity. The working hypothesis was that both techniques (EMBLOCK and LGEL) similarly blunt the cardiovascular responses to the stimulation. Six beagles were anesthetized using alfaxalone and isoflurane on three occasions with each treatment (EMBLOCK, LGEL, and control) in random order. The nasal cavity from the nose tip to the medial canthus was stimulated with a standard-tip cotton swab, and cardiovascular variables were recorded before and after stimulation. The maximum increases in heart rate and blood pressure were significantly smaller in EMBLOCK and LGEL than in the control. There was no significant difference between EMBLOCK and LGEL. Therefore, although further clinical studies are required, EMBLOCK and LGEL can be used because both EMBLOCK and LGEL attenuated the cardiovascular response to mechanical stimulation of the nasal cavity in dogs.

Cone beam computed tomographic evaluation of infraorbital canal protrusion into the maxillary sinus and its importance for endoscopic surgery.

OBJECTIVE: The aim of this retrospective study is to investigate the prevalence of Infraorbital Canal Protrusion (ICP) degree into the maxillary sinus and its relationship with variations in adjacent structures on Cone Beam Computed Tomography (CBCT) images. METHODS: 350 CBCT images (700 Infraorbital Canal [IC]) were evaluated retrospectively. ICP was divided into 3 subtypes according to the protrusion degree. The correlation between IC types and variations in adjacent anatomical structures (Haller cell, middle nasal concha pneumatization, maxillary sinus mucosal thickening and septa) was evaluated. The distance between Infraorbital Canal and Cnine Root (IC-CR) was also measured. For type 3, measurements were performed on IC as the length of the bony septum from the IC to the Mxillary Sinus Wall (IC-MSW), the distance from the inferior orbital rim, where the IC begins to protrude into the maxillary sinus (IOR-ICP), the vertical distance from the IC to the Maxillary Sinus Roof (IC-MSR) and Floor (IC-MSF). RESULTS: The prevalence of type 1, 2 and 3 was 62.9%, 29.1%, and 8% respectively. IC-CR was 10.2, 10.7 and 11.4 mm in type 1, 2 and 3, respectively. IC-MSW, IOR-ICP, IC-MSR and floor IC-MSF was 3.8, 10.9, 7.4 and 27.7 mm, respectively. On the right and left side, statistically significant correlation was found between IC types and the presence of the Haller cell and sinus septa. But there was no significant correlation between IC types and middle concha pneumatization. CONCLUSION: Accurate diagnosis of ICP is very important in preventing infraorbital nerve damage in surgical procedures to be performed in the maxillary region. The results of this study could be a guide for surgical planning in this region. LEVEL OF EVIDENCE: Retrospective study.

Ethmoidal and maxillary nerve block versus systemic opioid administration during rhinoscopy in dogs: a non-randomised clinical trial.

OBJECTIVES: This study aimed to evaluate the clinical effects of ethmoidal and maxillary nerve blocks during rhinoscopy in dogs. MATERIALS AND METHODS: Fourteen dogs underwent rhinoscopy. Under general anaesthesia with isoflurane, ethmoidal and maxillary nerve blocks were applied bilaterally using 2% lidocaine before rhinoscopy in eight dogs (EM group). Six dogs were premedicated with hydromorphone (0.05 mg/kg) as a substitute for local nerve block (H group). During rhinoscopy, the heart rate, arterial blood pressure and end-tidal isoflurane concentration were recorded. The vaporizer setting was adjusted to increase the end-tidal isoflurane concentration when reflex movement was caused by nasal stimulation. RESULTS: The H group, compared to the EM group, had an increase in HR that was 18 beats/minute (95% CI: 11 to 26) higher, an increase in SAP that was 22 mmHg (12 to 31) higher, an increase in MAP that was 15 mmHg (7 to 23) higher, an increase in DAP that was 12 mmHg (5 to 19) higher, and an increase in end-tidal isoflurane concentration that was 0.4% (0.3 to 0.5) higher. Head movement due to endoscope insertion was observed in 5/6 dogs (83.3%) in the H group and 1/8 dogs (12.5%) in the EM group (odds ratio, 0.029; ra95% CI, 0.001-0.574). CLINICAL SIGNIFICANCE: Compared with administration of 0.05 mg/kg hydromorphone, concurrent block of the ethmoidal and maxillary nerves can reduce the cardiovascular response, reflex movement and anaesthetic requirement during rhinoscopy in dogs.

Anatomical localisation of the maxillary nerve with the use of computed tomography to aid nerve block placement in dogs.

BACKGROUND: The maxillary block is a commonly used anaesthetic technique in dogs; however, no universal recommendations for the best method to perform this block exist. Differences between using this block in brachycephalic and non-brachycephalic breeds have not been examined. This study compared the position of the maxillary nerve using CT in brachycephalic and non-brachycephalic dogs. METHODS: Forty CT images of the heads of dogs of varying conformation were analysed. The distances and angles to the maxillary nerve from the injection site within the oral cavity were measured. If present in the same plane, the distance to the eye was measured. Measurements of jaw width and length were taken to ascertain if they correlated to the distance to the maxillary nerve from the oral cavity. RESULTS: There was no difference in angle between brachycephalic and non-brachycephalic dogs; however, the distance between nerve and injection point in brachycephalic dogs was generally greater. A regression equation relating maxillary nerve depth to jaw width was found. The eye was more likely to be in the plane of injection if the dog was non-brachycephalic. CONCLUSION: The discovered relationship between jaw width and maxillary nerve depth may allow more accurate injections to be made.

Implications of an Anatomical Variation of the Infraorbital Nerve in Orbital Floor Reconstruction.

ABSTRACT: Fractures involving the orbital floor such as blow-out fractures may cause damage to the infraorbital nerve (ION). The integrity and course of the nerve should be evaluated preoperatively in order to prevent from such nerve injuries. The anatomy of the ION can show variations in significant number of patients, which should be taken into account in treatment planning. In this report, the authors present a patient with an isolated fracture of the orbital floor, who had abnormal anatomy of his both IONs. Our treatment approach for this patient is presented along with relevant literature findings.

Evaluation of bilateral maxillary nerve block in dogs undergoing surgery for brachycephalic obstructive airway syndrome.

This retrospective study assessed the effect of an intraoral bilateral maxillary nerve block in dogs undergoing surgery for brachycephalic obstructive airway syndrome (BOAS). Records of dogs that underwent BOAS surgery were retrieved. Cases were assigned to Group B or C if a preoperative bilateral maxillary nerve block was performed or not. Type and dose of local anesthetic, inhalant anesthetic minimum alveolar concentration multiples, intraoperative fentanyl and injectable anesthetic use, prevalence of intraoperative hypotension or bradycardia, and postoperative opioids administration, were compared between groups. Sixty-seven cases met the inclusion criteria: 33 were assigned to Group B and 34 to Group C. In Group C, 18 dogs required intraoperative fentanyl (P = 0.005), and 12 needed injectable anesthetic top-ups (P = 0.006). Hypotension, or bradycardia, were not different between groups. Bilateral maxillary nerve block reduces intraoperative fentanyl and injectable anesthetic requirement in dogs undergoing BOAS surgery.

Évaluation du bloc nerveux maxillaire bilatéral chez les chiens brachycéphales opérés pour un syndrome obstructif des voies respiratoires. Cette étude rétrospective a évalué l'effet d'un bloc nerveux maxillaire intra-oral bilatéral chez des chiens brachycéphales subissant une intervention chirurgicale pour le syndrome obstructif des voies respiratoires (BOAS). Les dossiers des chiens qui ont subi une chirurgie BOAS ont été récupérés. Les cas ont été classés dans le groupe B ou C si un bloc du nerf maxillaire bilatéral préopératoire était réalisé ou non. Le type et la dose d'anesthésique local, les multiples de concentration alvéolaire minimale d'anesthésique par inhalation, l'utilisation peropératoire de fentanyl et d'anesthésiques injectables, la prévalence de l'hypotension ou de la bradycardie peropératoire et l'administration postopératoire d'opioïdes ont été comparés entre les groupes. Soixante-sept cas répondaient aux critères d'inclusion : 33 ont été affectés au groupe B et 34 au groupe C. Dans le groupe C, 18 chiens ont eu besoin de fentanyl peropératoire (P = 0,005) et 12 ont eu besoin de compléments anesthésiques injectables (P = 0,006). L'hypotension ou la bradycardie n'étaient pas différentes entre les groupes. Le bloc nerveux maxillaire bilatéral réduit les besoins peropératoires en fentanyl et en anesthésique injectable chez les chiens subissant une chirurgie BOAS.(Traduit par Dr Serge Messier).