The Maxillary Nerve Block in Cleft Palate Care: A Review of the Literature and Expert's Opinion on the Preferred Technique of Administration.

INTRODUCTION: Although the maxillary nerve block (MNB) provides adequate pain relief in cleft palate surgery, it is not routinely used globally, and reported techniques are heterogeneous. This study aims to describe relevant anatomy and to present the preferred technique of MNB administration based on the current literature and the expert opinion of the authors. METHOD AND MATERIALS: First, a survey was sent to 432 registrants of the International Cleft Palate Master Course Amsterdam 2023. Second, MEDLINE (PubMed interface) was searched for relevant literature on maxillary artery (MA) anatomy and MNB administration in pediatric patients. RESULTS: Survey response rate was 18% (n=78). Thirty-five respondents (44.9%) used MNB for cleft palate surgery before the course. A suprazygomatic approach with needle reorientation towards the ipsilateral commissure before incision was most frequently reported, mostly without the use of ultrasound. Ten and 20 articles were included on, respectively, MA anatomy and MNB administration. A 47.5% to 69.4% of the MA's run superficial to the lateral pterygoid muscle and 32% to 52.5% medially. The most frequently described technique for MNB administration is the suprazygomatic approach. Reorientation of the needle towards the anterior aspect of the contralateral tragus appears optimal. Needle reorientation angles do not have to be adjusted for age, unlike needle depth. The preferred anesthetics are either ropivacaine or (levo)bupivacaine, with dexmedetomidine as an adjuvant. CONCLUSION: Described MNB techniques are heterogeneous throughout the literature and among survey respondents and not routinely used. Further research is required comparing different techniques regarding efficacy and safety.

Three-dimensional printed personalised digital guide plate for greater palatine block in trigeminal neuralgia.

The nerve block is a safe and effective method to theat trigeminal neuralgia (TN). In terms of the V2 trigeminal neuralgia, the most difficult procedure in nerve block is accurate and fast greater palatine foramen (GPF) insertion. In this study, we developed a new technique using a personalised digital tooth-supported guide plate to increase insertion accuracy and success rates and reduce the pain of patients during injection. A total of 18 patients with TN (11 female and 7 male) were enrolled and treated between September 2020 and June 2022. Before injection, the guide plate was designed via Mimics three-dimensional (3D) reconstruction technology and printed via 3D printer. Then, all patients underwent maxillary nerve block with a guide plate for each injection. In this study, placement of all guide plates was completed within one minute and all punctures were successful the first time. The depth of the injection needle was over 2.5 cm in all cases and the guide plate was stability-supported by the maxillary teeth. The various pain scores had an obvious improvement. No patients presented symptoms of local anaesthetic toxicity or onset of new neurological sequelae. Using this new technology, we can significantly reduce the difficulty of GPF insertion and decrease patient pain during injection. The enhanced success rate of nerve block can achieve better therapeutic effect. For surgeons, personalised digital tooth-supported guide plates make the operation easier, especially for novice surgeons.

Canalis Sinuosus Mimicking Periapical Pathology on, Radiographic Assessment.

The canalis sinuosus is an anatomical variation whereby the infraorbital canal sometimes generates a small, lateral branch (canal) close to its midpoint, to allow the passage of the anterior superior alveolar neurovascular bundle in the anterior maxilla. This article focuses on an incidental finding of this variant, in a 74-year-old Trinidadian female of Afro-Caribbean descent with an endodontic presenting complaint. The canalis sinuosus shadow on conventional radiography resulted in uncertainty as to the offending tooth until a 3-dimensional scan was undertaken in this region. This report will discuss the implications of the presence of this canal from radiologic, endodontic, and surgical perspectives.

Rhinogenic Headache: The Dehiscence of Infraorbital Nerve.

Rhinogenic headache (RH), arising from nasal and sinus pathologies, present a diagnostic challenge due to their diverse etiologies. This study investigates a unique case where RH coincides with infraorbital nerve dehiscence, delving into the intricate relationship between sinonasal anatomy and neurovascular complications. The infraorbital nerve contacted a cyst in the maxillary sinus. Centripetal endoscopic sinus surgery was performed to open the maxillary sinus and remove the cyst. After 3 months of follow-up, the patient had a notable improvement in symptoms with a reduced headache. This case highlights the significance of considering uncommon anatomic variations, such as infraorbital nerve dehiscence, within the context of RH. Diligent history-taking and appropriate use of radiologic investigations are pivotal for guiding clinicians toward an accurate diagnosis and determining the most appropriate course of treatment.

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.

A Feasibility Study for a Novel Trans-infraorbital Canal Approach to the Maxillary Nerve in Pigs (Sus domesticus).

Experimental maxillofacial surgery is commonly performed in pigs; however, locoregional anesthesia of this area has not been described. This study evaluated the feasibility of a novel maxillary nerve block approach. In part I, cadavers were used to determine anatomic landmarks and assess maxillary nerve dye staining by using 0.03 mL kg-1 of a 1:10 mixture of commercial food dye and 0.5% bupivacaine. In part II, 10 additional pig cadavers underwent bilateral ultrasound-guided maxillary nerve blocks by using trans-infraorbital canal needle placement. The maxillary nerve was harvested and scored based on degree of staining (0 and 1, absent or incomplete staining; 2, staining; >1 cm circumferentially). Intracranial and intraconal spread of dye was evaluated. A Kruskal-Wallis test was used to compare infraorbital canal length estimated either externally via landmarks, internally via ultrasound, or actually measured after dissection. In 18 of 20 (90%) injections, successful staining (score = 2) of maxillary nerves was obtained for a nerve length of 2.4 ± 0.3 cm. Two of 20 cases (10%) had inadequate staining (score <2). At dissection of these 2 cases, the needle tip was observed to have collided with an unerupted tooth (third molar). No intracranial or intraconal spread of dye was observed. We detected no statistical differences between the estimated external, estimated internal, or actual dissection methods for measurement of infraorbital canal length (P = 0.3). Ultrasound-guided trans-infraorbital maxillary nerve block in pigs is a feasible technique, warranting further work to evaluate its in vivo efficacy and safety.

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.

Transorbital Endoscopic Approach to the Foramen Rotundum for Infraorbital Nerve Stripping.

PURPOSE: To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch. METHODS: Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits). RESULTS: The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal). CONCLUSIONS: The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology.

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.

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.

Alterações oftalmológicas decorrentes da anestesia local: aspectos de interesse para a odontologia / Ophthalmologic changes associated from local anesthesia: aspects of interest to dentistry

As complicações oftalmológicas decorrentes do uso de anestésicos locais em odontologia apresentam um baixo índice de ocorrência. Entretanto, torna-se fundamental o reconhecimento e conduta do cirurgião-dentista frente a essas possíveis complicações. O trabalho em questão tem como objetivo a identificação das alterações oftalmológicas decorrentes da injeção de anestésicos locais. Foi realizada uma revisão de literatura descrevendo as possíveis fisiopatologias, as estruturas mais acometidas, as técnicas anestésicas mais suscetíveis, bem como, a correta conduta caso ocorra e a importância do diagnóstico diferencial, visto que as alterações oftalmológicas estão presentes em outras alterações, como lesões centrais. Dessa forma pode-se concluir que as complicações, embora temporárias e geralmente benignas, podem ser angustiantes tanto para o paciente quanto para o profissional, sendo de extrema importância o reconhecimento das estruturas alteradas, possibilitando a devida explicação ao paciente e conduta a ser executada.

Ophthalmologic complications resulting from the use of local anesthetics in dentistry have a low rate of occurrence. However, it is essential to recognize and conduct the dentist in the face of these possible complications. This study aims to identify ophthalmologic alterations resulting from the injection of local anesthetics. A literature review was conducted describing the possible pathologies, the most affected structures, the most susceptible anesthetic techniques, as well as the correct conduct if it occurs and the importance of the differential diagnosis, since ophthalmologic alterations are present in other alterations, such as central lesions. Complications, although temporary and generally benign, can be distressing for both the patient and the professional, being extremely important the recognition of altered structures, allowing proper explanation to the patient and conduct to be performed.

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.