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Background: The foramen rotundum and anterior cavernous sinus have traditionally been accessed by transcranial approaches that are limited by the high density of critical neurovascular structures. The transmaxillary approach provides an entirely extradural route to the foramen rotundum and anterior cavernous sinus. Method: This patient with neurofibromatosis and facial pain with trigeminal schwannoma at the foramen rotundum was successfully treated by transmaxillary resection of the tumor. This approach allowed for a direct extradural access to the pathology, with bony decompression and tumor resection, avoiding transcranial routes. Conclusion: The transmaxillary approach provides a safe and entirely extradural corridor to access smaller localized skull base lesions at and surrounding the cavernous sinus. [ABSTRACT FROM AUTHOR]

This article, published in the Journal of Neurological Surgery, describes a new strategy for treating trigeminal neuralgia called nerve combing via "peeling" of the middle fossa. The authors performed microsurgical dissection on cadaveric heads to demonstrate the technique. They successfully performed nerve combing from the root entry zone to the Gasserian ganglion using a middle fossa approach. This new strategy provides a direct route to access both the cisternal segment of the trigeminal nerve and the Gasserian ganglion, offering a potential solution for patients who have not responded to previous treatments. [Extracted from the article]

This article discusses the importance of the palatine bone in endoscopic endonasal skull base surgery. The study examines the structure of the palatine bone and its relationship with surrounding bones, as well as its role in identifying and exposing vital neurovascular structures. The palatine bone contains complex structures that are closely related to arteries, nerves, and branches, making it a useful landmark for surgeons. The article concludes that the palatine bone has not received much attention in skull base surgery, but it harbors important landmarks for maximizing the surgical corridor and minimizing unnecessary injury to neurovascular structures. [Extracted from the article]

Background: The foramen rotundum and anterior cavernous sinus have traditionally been accessed by transcranial approaches that are limited by the high density of critical neurovascular structures. The transmaxillary approach provides an entirely extradural route to the foramen rotundum and anterior cavernous sinus. Method: This patient with neurofibromatosis and facial pain with trigeminal schwannoma at the foramen rotundum was successfully treated by transmaxillary resection of the tumor. This approach allowed for a direct extradural access to the pathology, with bony decompression and tumor resection, avoiding transcranial routes. Conclusion: The transmaxillary approach provides a safe and entirely extradural corridor to access smaller localized skull base lesions at and surrounding the cavernous sinus. [ABSTRACT FROM AUTHOR]

To investigate and describe an extraoral approach to perform a maxillary nerve block in guinea pigs. Prospective, randomized, blinded, descriptive, cadaveric study. A total of 14 adult guinea pig cadavers. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Background: Meckel's cave is a challenging surgical target due to its deep location and proximity to vital neurovascular structures. Surgeons have developed various microsurgical transcranial approaches (MTAs) to access it, but there is no consensus on the best method. Newer endoscopic approaches have also emerged. This study seeks to quantitatively compare these surgical approaches to Meckel's cave, offering insights into surgical volumes and exposure areas. Methods: Fifteen surgical approaches were performed bilaterally in six specimens, including the pterional approach (PTA), fronto-temporal-orbito-zygomatic approach (FTOZA), subtemporal approach (STA), Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), endoscopic endonasal transpterygoid approach (EETPA), inferolateral transorbital approach (ILTEA) and superior eyelid approach (SEYA). All the MTAs were performed both with 10 mm and 15 mm of brain retraction, to consider different percentages of surface exposure. A dedicated navigation system was used to quantify the surgical working volumes and exposure of different areas of Meckel's cave (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Microsurgical transcranial approaches were quantified with two different degrees of brain retraction (10 mm and 15 mm). Statistical analysis was performed using a mixed linear model with bootstrap resampling. Results: The RSAS with 15 mm of retraction offered the maximum exposure of the trigeminal stem (TS). If compared to the KWA, the RSA exposed more of the TS (69% vs. 46%; p = 0.01). The EETPA and ILTEA exposed the Gasserian ganglion (GG) mainly in the anteromedial portion, but with a significant 20% gain in exposure provided by the EETPA compared to ILTEA (42% vs. 22%; p = 0.06). The STA with 15 mm of retraction offered the maximum exposure of the GG, with a significant gain in exposure compared to the STA with 10 mm of retraction (50% vs. 35%; p = 0.03). The medial part of the three trigeminal branches was mainly exposed by the EETPA, particularly for the ophthalmic (66%) and maxillary (83%) nerves. The EETPA offered the maximum exposure of the medial part of the mandibular nerve, with a significant gain in exposure compared to the ILTEA (42% vs. 11%; p = 0.01) and the SEY (42% vs. 2%; p = 0.01). The FTOZA offered the maximum exposure of the lateral part of the ophthalmic nerve, with a significant gain of 67% (p = 0.03) and 48% (p = 0.04) in exposure compared to the PTA and STA, respectively. The STA with 15 mm of retraction offered the maximum exposure of the lateral part of the maxillary nerve, with a significant gain in exposure compared to the STA with 10 mm of retraction (58% vs. 45%; p = 0.04). The STA with 15 mm of retraction provided a significant exposure gain of 23% for the lateral part of the mandibular nerve compared to FTOZA with 15 mm of retraction (p = 0.03). Conclusions: The endoscopic approaches, through the endonasal and transorbital routes, can provide adequate exposure of Meckel's cave, especially for its more medial portions, bypassing the impediment of major neurovascular structures and significant brain retraction. As far as the most lateral portion of Meckel's cave, MTA approaches still seem to be the gold standard in obtaining optimal exposure and adequate surgical volumes. [ABSTRACT FROM AUTHOR]

Metastatic skull base malignancies infrequently occur but, when present, typically arise from breast malignancies. Pterygopalatine fossa (PPF) metastasis of any malignancy is further seldom reported, and metastasis of gynecologic malignancies to the PPF has not been previously described in the literature. We present a single case of a 42-year-old female with the first likely case of high-grade endometrial sarcoma metastatic to the PPF. The patient presented with facial pain and numbness in the V2 distribution presented for evaluation. History was significant for several months of dysmenorrhea and metrorrhagia. Computed tomography, magnetic resonance imaging, and positron emission tomography imaging revealed a PPF mass with local extension and bony metastases. Endoscopic biopsy was performed, and final pathology was most consistent with metastatic high-grade endometrial stromal sarcoma. This is the first reported case of likely metastatic endometrial sarcoma to the PPF. This case report highlights the possibility of rare distant metastasis of gynecologic malignancy to this area of the skull base. [ABSTRACT FROM AUTHOR]

The infraorbital nerve is responsible for the sensory innervation of the lower eyelid, the lateral nose, the cheek, the upper lip, and the maxillary teeth. It passes along the infraorbital canal, which runs superior to the maxillary sinus. Dehiscence of the infraorbital canal and its ectopic course in the maxillary sinus is a rare variation. A nerve with these variations may be affected by pathologies in the maxillary sinus and this may constitute a rare cause of facial pain. In this report, we present the clinical symptoms of a 29-year-old male patient who had an infraorbital nerve with an ectopic course and dehiscence in light of the literature. [ABSTRACT FROM AUTHOR]

The endoscopic transorbital approach (ETOA) is a minimally invasive approach that could be particularly appropriate for management of spheno-orbital meningiomas. The aim of this study was to perform a systematic review of the literature on the management of spheno-orbital meningiomas via the minimally invasive ETOA, searching for clinical scenarios in which this approach could be best indicated. A secondary aim was to describe 4 illustrative cases. A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data including patient demographics, tumor features, and surgical and postoperative outcomes were collected. Cases from our initial experience with ETOA were included in the data. Data of 58 patients from 9 selected records and from our surgical series were collected. Subtotal, near-total, and gross total resection rates were 44.8%, 10.3%, and 32.7%, respectively. Symptom improvement after surgery was 100% for proptosis, 93% for visual impairment, and 87% for ophthalmoplegia. The most common postoperative complications were transient ophthalmoplegia and maxillary nerve hypoesthesia. Cerebrospinal fluid leak was reported in 2 patients. Our findings support the use of the ETOA for management of spheno-orbital meningiomas, particularly in at least 3 clinical scenarios: 1) when predominant hyperostotic bone is present; 2) when a globular tumor not showing excessive medial or inferior infiltration is being treated; 3) as part of a multistage treatment for diffuse lesions. [ABSTRACT FROM AUTHOR]

BACKGROUND: The implant template can effectively transfer the implant designed position to the patient’s jaw. It helps implant avoid important anatomical structures such as nerve and maxillary sinus, and effectively reduces the risk of surgery. Therefore, the accuracy of implant template surgery is particularly important. OBJECTIVE: To assess the design and manufacturing error of the tooth-supported surgical template and its implant accuracy in the fully positioned state. METHODS: A patient with missing teeth underwent a cone beam CT and a plaster model was established. According to the patien’s oral situation, implant plan with special positioning surface tooth-supported template was designed and implant template was made. Stereo Lithography Apparatus rapid prototyping technology was used to fabricate 10 templates and three-dimensional laser scanning was performed. After matching the scanning data with designed template model data, manufacturing error analysis was carried out. In addition, the 10 manufactured templates were worn on the patient’s plaster model to simulate implant position, and the simulated implant positions were matched with initial implant positions in the design plan for accuracy analysis. RESULTS AND CONCLUSION: (1) The mean positive deviation of the template was 0.093 mm; the mean negative deviation was 0.092 mm, and the mean standard deviation was 0.169 mm. (2) The simulated implant accuracy results showed that the neck center deviation of implant 12 was (1.172±0.283) mm; the top center deviation was (1.339±0.283) mm; the central axis angle deviation was (0.365±0.228)°; the neck center deviation of implant 21 was (1.274±0.379) mm; the top center deviation was (1.461±0.404) mm, and the center axis angle deviation was (0.643±0.276)°. (3) These results indicate that the design and manufacturing error of tooth-supported template with a specific positioning surface has a significant impact on implant accuracy. [ABSTRACT FROM AUTHOR]

To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Although in counterpart, the sphenopalatine artery (SPA), has been well described in the medical literature, the sphenopalatine vein (SPV) has received scant attention. Therefore, the present anatomical study was performed. Additionally, we discuss the variations, embryology, and clinical significance of the SPV. Adult cadaveric specimens underwent dissection of the SPV. In addition, some specimens were submitted for histological analysis of this structure. The SPV was found to drain from the sphenoidal sinus and nasal septum. Small tributaries traveled through the nasal septum with the posterior septal branches of the SPA and nasopalatine nerve. The SPA and SPV were found to travel through the sphenopalatine foramen and another tributary was found to perforate the medial plate of the pterygoid process and to connect to the pterygoid venous plexus which traveled lateral to the medial plate of the pterygoid process. The vein traveled through the posterior part of the lateral wall of the nasal cavity with the posterior lateral nasal branches of the SPA and the lateral superior posterior nasal branches of the maxillary nerve. To our knowledge, this is the first anatomical study on the SPV in humans. Data on the SPV provides an improved anatomical understanding of the vascular network of the nasal cavity. Developing a more complete picture of the nasal cavity and its venous supply might help surgeons and clinicians better manage clinical entities such as posterior epistaxis, cavernous sinus infections, and perform endoscopic surgery with fewer complications. [ABSTRACT FROM AUTHOR]

Purpose: Accessory sphenoidal septum (ASS) is a septal variation that exists in addition to the primary septum of the sphenoid sinus and can be found in or near anatomically essential structures. This study aimed to investigate the relationships between protrusions of vital structures around the sphenoid sinus and the ASSs. Methods: This cross-sectional retrospective study is based on the analysis of CBCT scans of 314 patients in axial, coronal, and sagittal planes with 0.2–0.3 slice thicknesses. Optic nerve (ON), internal carotid artery (ICA), both ON and ICA, maxillary nerve (MN), vidian canal (VN) and ASSs were detected, and the relationship between protrusions of these vital anatomical structures and ASS was evaluated. Results: Statistically significant relationship was observed between the right Type 1 ON protrusion (p < 0.05) and left Type 1 ON protrusion (p = 0.001); left Type 3 ON protrusion (p < 0.05); right Type 4 ON protrusion (p < 0.05) and ASS. Statistically significant relationship was also observed between the right ICA protrusion and ASS (p < 0.05). The right Type 1 VN protrusion (p = 0.001); left Type 2 VN protrusion (p < 0.001); right and left Type 3 VN protrusions (p < 0.001) were found to be significantly associated with the ASS. Conclusions: ASSs have significant associations with some protrusions, and they tend to cause potentially severe complications in endoscopic sinus surgery. This variability requires a comprehensive understanding of regional sphenoid sinus anatomy with detailed three-dimensional tomographic imaging. [ABSTRACT FROM AUTHOR]

Objectives: The detailed pathological mechanism of orofacial neuropathic pain remains unknown. We aimed to examine the pannexin 1 (Panx1) signaling in the trigeminal ganglion (TG) involvement in infraorbital nerve injury (IONI)‐induced orofacial neuropathic pain. Materials and Methods: Mechanical head‐withdrawal threshold (MHWT) was measured in IONI‐treated rats receiving intra‐TG Panx1 inhibitor or metabotropic glutamate receptor 5 (mGluR5) antagonist administration and MHWTs in naive rats receiving intra‐TG mGluR5 agonist administration post‐IONI. Glutamate and Panx1 in the TG were measured post‐IONI. Panx1, mGluR5, and glutamine synthetase expression in TG were immunohistochemically identified, and changes in the number of mGluR5‐P2X3‐expressed TG neurons were examined. Results: MHWT was significantly decreased post‐IONI, and this decrease was reversed by Panx1 inhibition or mGluR5 antagonism. mGluR5 agonism induced a decrease in the MHWT. IONI increased extracellular glutamate in TG. Panx1 was expressed in satellite glial cells and TG neurons, and intra‐TG mGluR5 antagonism decreased the number of mGluR5 and P2X3 positive TG neurons post‐IONI. Conclusions: IONI facilitates glutamate release via Panx1 that activates mGluR5 which was expressed in the nociceptive TG neurons innervating the orofacial region. In turn, P2X3 receptor‐expressed TG neurons are enhanced via mGluR5 signaling, resulting in orofacial neuropathic pain. [ABSTRACT FROM AUTHOR]

We report the results of an experiment in which electrophysiological activity was recorded from the human cerebellum and cerebrum in a sample of 14 healthy subjects before, during and after a classical eye blink conditioning procedure with an auditory tone as conditional stimulus and a maxillary nerve unconditional stimulus. The primary aim was to show changes in the cerebellum and cerebrum correlated with behavioral ocular responses. Electrodes recorded EMG and EOG at peri‐ocular sites, EEG from over the frontal eye‐fields and the electrocerebellogram (ECeG) from over the posterior fossa. Of the 14 subjects half strongly conditioned while the other half were resistant. We confirmed that conditionability was linked under our conditions to the personality dimension of extraversion‐introversion. Inhibition of cerebellar activity was shown prior to the conditioned response, as predicted by Albus (1971). However, pausing in high frequency ECeG and the appearance of a contingent negative variation (CNV) in both central leads occurred in all subjects. These led us to conclude that while conditioned cerebellar pausing may be necessary, it is not sufficient alone to produce overt behavioral conditioning, implying the existence of another central mechanism. The outcomes of this experiment indicate the potential value of the noninvasive electrophysiology of the cerebellum. [ABSTRACT FROM AUTHOR]

The anatomical framework of the jawbones is highly conserved among most of the Osteichthyes, including the tetrapods. However, our recent study suggested that the premaxilla, the rostralmost upper jaw bone, was rearranged during the evolution of therian mammals, being replaced by the septomaxilla at least in the lateral part. In the present study, to understand more about the process of evolution from the ancestral upper jaw to the therian face, we re‐examined the development of the therian premaxilla (incisive bone). By comparing mouse, bat, goat, and cattle fetuses, we confirmed that the therian premaxilla has dual developmental origins, the lateral body and the palatine process. This dual development is widely conserved among the therian mammals. Cell‐lineage‐tracing experiments using Dlx1‐CreERT2 mice revealed that the palatine process arises in the ventral part of the premandibular domain, where the nasopalatine nerve distributes, whereas the lateral body develops from the maxillary prominence in the domain of the maxillary nerve. Through comparative analysis using various tetrapods, we concluded that the palatine process should not be considered part of the ancestral premaxilla. It rather corresponds to the anterior region of the vomerine bone of nonmammalian tetrapods. Thus, the present findings indicate that the true premaxilla was completely lost during the evolution of the therian mammals, resulting in the establishment of the unique therian face as an evolutionary novelty. Reconsideration of the homological framework of the cranial skeleton based on the topographical relationships of the ossification center during embryonic development is warranted. Research Highlights: The rostralmost jawbone, the incisive bone of therian mammals, was established by fusion of the septomaxilla and a part of the vomerine bone in the nonmammalian tetrapods. The true premaxilla was completely lost, and the corresponding region became the motile nose. These changes drove the evolution of the unique therian face. [ABSTRACT FROM AUTHOR]

Background: Children undergoing cleft palate repair present challenges to postoperative management due to several factors that can complicate recovery. Utilization of multimodal analgesic protocols can improve outcomes in this population. We report experience designing and implementing an enhanced recovery after surgery (ERAS) pathway for cleft palate repair to optimize postoperative recovery. Aims: The primary aim was to implement an ERAS pathway with >70% bundle adherence to achieve a 30% reduction in postoperative opioid consumption within 12 months. Our secondary aims assessed intraoperative opioid consumption, length of stay, timeliness of oral intake, and respiratory recovery. Methods: A multidisciplinary team of perioperative providers developed an ERAS pathway for cleft palate patients. Key drivers included patient and provider education, formal pathway creation and implementation, multimodal pain therapy, and target‐based care. Interventions included maxillary nerve blockade and enhanced intra‐ and postoperative medication regimens. Outcomes were displayed as statistical process control charts. Results: Pathway compliance was 77.0%. Patients during the intervention period (n = 39) experienced a 49% reduction in postoperative opioid consumption (p <.0001) relative to our historical cohort (n = 63), with a mean difference of −0.33 ± 0.11 mg/kg (95% CI −0.55 to −0.12 mg/kg). Intraoperative opioid consumption was reduced by 36% (p =.002), with a mean difference of −0.27 ± 0.09 mg/kg (95% CI −0.45 to −0.09 mg/kg). Additionally, patients in the intervention group had a 45% reduction in time to first oral intake (p =.02) relative to our historical cohort, with a mean difference of −3.81 ± 1.56 h (95% CI −6.9 to −0.70). There was no difference in PACU or hospital length of stay, but there was a significant reduction in variance of all secondary outcomes. Conclusion: Opioid reduction and improved timeliness of oral intake is possible with an ERAS protocol for cleft palate repair, but our protocol did not alter PACU or hospital length of stay. [ABSTRACT FROM AUTHOR]

Objectives  The vidian nerve provides parasympathetic innervation to the nasal cavity and the lacrimal gland. Previous anatomic studies have primarily focused on preservation or severance of the vidian nerve proximal to the pterygopalatine ganglion (PPG). This study aimed to assess its neural fibers within the pterygopalatine fossa after synapsing at the PPG, and to explore potential clinical implications for endoscopic endonasal skull base surgery. Methods  An endonasal transpterygoid approach was performed on eight cadaveric specimens (16 sides). The PPG and maxillary nerve within the pterygopalatine fossa were divided. The vidian nerve was traced retrograde into the foramen lacerum, and postganglionic fibers distal to the PPG were dissected following the zygomatic nerve into the orbit. Potential communicating branches between the ophthalmic nerve (V1) and the PPG were also explored. Results  All sides showed a plexus of neural communications between the PPG and the maxillary nerve. The zygomatic nerve exits the maxillary nerve close to the foramen rotundum, piercing the orbitalis muscle to enter the orbit in all sides. The zygomatic nerve was identified running beneath the inferior rectus muscle toward a lateral direction. In 7/16 sides (43.75%), a connecting branch between V 1 and the pterygopalatine ganglion was observed. Conclusion  Neural communications between the PPG and the maxillary nerve were present in all specimens. A neural branch from V 1 to the PPG potentially contributes additional postganglionic parasympathetic function to the lacrimal gland. [ABSTRACT FROM AUTHOR]

Objective: Endoscopic endonasal surgery is a minimally invasive technique that has revolutionised the management of complex neurosurgical, otolaryngological, skull-base and craniofacial lesions. Traditionally performed under general anaesthetic, this study explores the growing role of local anaesthetic techniques. Method: A contemporaneous review of modified dental techniques and intraoral anatomy provides a supportive guide for performing endoscopic sinus surgery under local anaesthetic. Results: The practical procedures for four midfacial nerve blocks are described with relevance to endoscopic surgery under local anaesthetic. Anatomy, surgical technique and potential complications are discussed for the incisive foramen block, sphenopalatine ganglion block (via endonasal approach), maxillary nerve block (via the greater palatine foramen and the transoral lateral pterygoid plate approach) and transcutaneous approach to the pterygomaxillary fissure. Conclusion: Ultimately, such techniques may extend the safety and efficacy of endoscopic sinus surgery, limit surgical risk and increase satisfaction for patients, surgeons and healthcare managers alike. [ABSTRACT FROM AUTHOR]

Introduction  Understanding the anatomic features of the zygomatic nerve is critical for performing the endoscopic transmaxillary approach properly. Injury to the zygomatic nerve can result in facial numbness and corneal problems. Objective  To evaluate the surgical anatomy of the zygomatic nerve and its segments from an endoscopic endonasal perspective for clinical implications of performing the endoscopic transmaxillary approach. Methods  The origin, course, length, and segments of the zygomatic nerve were studied in four specimens from an endonasal perspective. Results  The zygomatic nerve arises 4.1 ± 1.7 mm from the foramen rotundum of the maxillary nerve in the superolateral pterygopalatine fossa (PPF). According to its anatomic region in endonasal endoscopic surgery, we divided the zygomatic nerve into two segments: the PPF segment, from origin to the point of entry under Muller's muscle, which runs superolaterally to the inferior orbital fissure (IOF) (length, 4.6 ± 1.3 mm), and the IOF segment, starting at the entry point in Muller's muscle and terminating at the exit point in the IOF, which travels between Muller's muscle and the great wing of the sphenoid bone (length, 19.6 ± 3.6 mm). In the transmaxillary approach, the zygomatic nerve is a critical landmark in the superolateral PPF. Conclusion  The zygomatic nerve travels in the PPF and the IOF; better visualization and preservation of this nerve during endonasal endoscopic surgery are crucial for successful outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Maxillary nerve (MN) desensitization can improve quality and safety of orofacial surgeries in horses, especially when a standing procedure is elected. The purpose of this retrospective study is to report results from 15 horses undergoing orofacial surgery which received an MN block with the retrograde approach within the infraorbital canal. The same technique was used in horses scheduled for orofacial surgeries and grouped as requiring general anesthesia or standing analgo-sedation. From the retrieved anesthetic records, regardless of the group, clinical and physiological parameters continuously monitored during surgery were stable, and none of the horses showed complications during or after the block. These results confirm the feasibility of this loco-regional anesthetic technique as a valid approach to the MN without risk of damaging periorbital structures, which is reported with traditional techniques. Evident landmarks for this approach and limited chances to injure vital structures enclosed within the infraorbital canal make the operator experience less relevant than the ability required to block the MN according to approaches, which currently aim at the pterygopalatine fossa. This substantiates the retrograde approach to block the MN is safe and easy to perform in horses undergoing orofacial surgeries at regions where this nerve provides sensory innervation. The aim of this study was to retrospectively report outcomes resulting from the approach to the maxillary nerve block (MNB) through the infraorbital canal, in terms of needles selection, drawbacks or side effects during or after block execution, and analgesic efficacy leading to clinical and cardiovascular stability during surgery. Anesthetic records of 15 horses undergoing orofacial surgery in standing analgo-sedation (STA, n = 6) and in general anesthesia (GEN, n = 9) were retrieved and analyzed. Horses in group STA required surgery for dental extraction, nasal polyp resection and maxillary/frontal sinusitis. Horses in group GEN underwent surgery for fronto-maxillary, nasal and dental diseases. Size 19 and 20 G Tuohy needles were used in adult horses weighing 350–600 kg, while size 21 and 22 G were used in younger horses or ponies. None of the horses in both groups showed complications related to the block and physiological parameters were stable and within normal ranges during surgery; overall, an adequate anesthetic/sedation depth was achieved. Our results confirm the in vivo applicability of the MNB approached within the infraorbital canal, which had been described only on cadaveric specimens. The retrograde technique resulted in a valid and easy approach to the maxillary nerve that avoids damage to periorbital structures and side effects reported with traditional techniques. [ABSTRACT FROM AUTHOR]

Local anaesthesia techniques are now essential parts of the multimodal analgesic approach applied in the care of small animals. The sensory innervation of the nose is provided by the maxillary division of the trigeminal nerve, so nasal pain can be prevented or alleviated by blocking branches of this nerve. Maxillary or infraorbital nerve block can be used if invasive procedures are performed on the nose of the canine and feline patients. Clear anatomical landmarks facilitate the placements of these blocks, which impose relatively low risk to the patients. These blocks do not require any advanced equipment and all necessary material is widely available in small animal veterinary practices. The total dose of the local anaesthetic agents should be calculated precisely to avoid toxicity. [ABSTRACT FROM AUTHOR]

Background: Because of the broad anatomic variation in the course of the axillary nerve, several cadaveric studies have investigated the acromion-axillary nerve distance and its association with the humeral length to predict the axillary nerve location. This study aimed to analyze the acromion-axillary nerve distance (AAND) and its relation to the arm length (AL) in patients who underwent internal plate fixation for proximal humerus fractures. Methods: The present prospective study involved 37 patients (15 female, 22 male; the mean age = 51 years, age range 19–76) with displaced proximal humerus fractures treated by open reduction and internal fixation. After anatomic reduction and fixation were achieved, the following parameters were measured in each patient before wound closure without making an extra incision or dissection: (1) the distance from the anterolateral edge of the acromion to the course of the axillary nerve was recorded as the acromion-axillary nerve distance and (2) the distance from the anterolateral edge of the acromion to the lateral epicondyle of the humerus was recorded as arm length. The ratio of AAND to AL was then calculated and recorded as the axillary nerve index (ANI). Results: The mean AAND was 6 ± 0.36 cm (range 5.5–6.6), and the mean arm length was 32.91 ± 2.9 cm (range 24–38). The mean axillary nerve ratio was 0.18 ± 0.02 (range 0.16 to 0.23). There was a significant moderate positive correlation between AL and AAND (p = 0.006; r = 0.447). The axillary nerve location was predictable in only 18% of the patients. Conclusion: During the anterolateral deltoid-splitting approach to the shoulder joint, 5.5 cm from the anterolateral edge of the acromion could be considered a safe zone to prevent possible axillary nerve injury. [ABSTRACT FROM AUTHOR]

The sphenoid sinus and related anatomy should be known considering the intimate relationships with vital surrounding structures, such as the internal carotid artery, the optic canal, the maxillary and the vidian nerves. The sphenoid sinus has numerous variations regarding the pneumatization, the septation and the relation with the neurovascular structures. Multiplanar sinus CT scan is mandatory in the preoperative evaluation of the patient to avoid injury during endoscopic sphenoidotomy. In this article, we review and describe the importance of the anatomical landmarks of the sphenoid sinus on the CT scan, the anatomic findings that augment the risk of complications during sphenoid sinus endoscopic surgery. Moreover, we discuss about the appropriate type of endoscopic approach of the sphenoid sinus depending on the localization of the pathologic process and the experience of the surgeon, as well as the endoscopic surgery challenges. We analysed 100 patients who addressed to our clinic in the last 6 months and who underwent CT of the paranasal sinuses and we studied the pneumatization type and the anatomic variations of the optic nerve and the internal carotid artery. A variety of sphenoid sinus anatomy variations were found, and we emphasize the value of imagining evaluation before performing functional endoscopic sinus surgery. [ABSTRACT FROM AUTHOR]

Background and Aims: The efficacy of bilateral nasociliary and maxillary nerve blocks combined with general anaesthesia on intraoperative opioids consumption, emergence and recovery outcomes in adult patients is not well established. We conducted this study to test the hypothesis that the above blocks, combined with general anaesthesia, decrease the intraoperative opioid consumption following nasal surgery. Methods: In this prospective, double-blinded, randomised controlled study, 51 adult patients undergoing elective nasal surgery under general anaesthesia were randomised into one of two groups. Group A (n = 26) received bilateral nasociliary and maxillary nerve blocks with 12 mL of equal volumes of 0.5% bupivacaine and 2% lignocaine after induction of general anaesthesia. Group B (n = 25) did not receive any block (control group). The primary endpoint was the total intraoperative dose of fentanyl consumed. The secondary endpoints were the grade of cough, emergence agitation, the grade of post-operative nausea and vomiting, time to the first analgesia and time to post-anaesthesia care unit discharge. Results: The mean total intraoperative fentanyl dose (μg) was significantly lower in group A than in group B (2.31 ± 11.76 vs. 41.20 ± 31.00, P = 0.00). The incidence of emergence agitation was lower in group A than group B (11.5% vs. 88%, P = 0.00). The time to the first analgesia was significantly longer in group A than group B (543.27 vs. 199.84 min, P = 0.017). Conclusion: The pre-emptive administration of bilateral nasociliary and maxillary nerve block for nasal surgery is an effective technique for reducing the intraoperative dose of fentanyl and emergence agitation. [ABSTRACT FROM AUTHOR]

Background: Alterations in the anatomical relationships of the musculocutaneous (MCN) and axillary nerves and the influence of arm positioning on these relationships after a Latarjet procedure have been demonstrated in the cadaver, but there are no studies in the literature that establish if there is any neurophysiological repercussion. Methods: We retrospectively identified 24 patients with a primary or revision open Latarjet procedure. A prospective clinical (Constant-Murley, Rowe and Walch-Duplay and active range of motion), radiographic (with CT), and electrodiagnostic evaluation was made at the most recent follow-up. Results: Nonunion occurred in four patients (22%); there were, as well, one case of partial coracoid reabsorption (5%) and two (11%) with mild glenohumeral osteoarthritis. In the anatomical position, we found no alterations in the musculocutaneous nerve and two cases (11%) in the axillary nerve slight motor unit loss. In the risk position, 11 cases (61%) had neurophysiological involvement (36% had neurophysiological changes in the musculocutaneous nerve and 64% in the axillary nerve). No differences between patients with or without neurophysiologic changes were found: Constant 87/83; Rowe 89/90; Walch-Duplay 84/78; Forward elevation 175º/170º, abduction 165°/175°; external rotation 48°/45°. Conclusion: The rate of clinical electromyographic changes in the axillary and MCN in the abducted and externally rotated arm position (risk dislocation position) is higher than in neutral position. Nonunion of the coracoid process must play a role in these neurophysiological changes. Although in the medium-term they don't have clinical impact, further randomized prospective studies with a larger sample size are necessary to determine their true repercussion. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: Greater palatine foramen is located in posterior part of hard palate. Knowledge of anatomical limitations of greater palatine foramen are crucial for injecting anaesthetic drugs along greater palatine nerve and for maxillary nerve block. Aim: Aim of the study was to provide anatomical data regarding number, possible shape, variability in location of greater palatine foramen and its relation to nearby landmarks. Material and methods: Study included 100 dry human skulls that assessed 200 greater palatine foramina. Various parameters were measured by using digital Vernier caliper. Results: Shape of GPF was oval in 57% on right & 51% on left side. It was directed anteromedial in 56% & 44% on right & left sides. Its position was at 3rd molar in 49% on right and 56% on left side. Mean of anteroposterior, transverse diameters & penetrability were 4.96mm, 3.37mm & 13.07mm on right and 4.78mm, 3.17mm & 12.15mm on left side respectively. Mean of distance between GPF of two sides was 31.23mm. The mean of distance of GPF from IF, IPS and PPB were 38.76, 15.58mm and 4.68mm on right side and 38.46mm, 15.33mm and 4.41mm on left side respectively. Conclusion: All metric observations were more on right as compared with left side. Present study will provide the required baseline data for various dental procedures and development of tools. [ABSTRACT FROM AUTHOR]

Background: Trigeminal neuralgia is sudden unilateral severe, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve. Pulsed radiofrequency stimulation (PRF) has been recently introduced to alleviate neural, joint pain, and muscle pain. We tried to use PRF for pain relief in trigeminal neuralgia. The primary objective of our study was to observe the effectiveness and safety of pulsed radiofrequency in the patients of trigeminal neuralgia who are refractory to medical management. The secondary objective was to study the effect of pulsed radiofrequency on the duration of pain relief in these patients. Methodolgy: In this observational study, we enrolled all fresh patients with trigeminal neuralgia attending our pain clinic for the first time and those who had not responded to conservative medical treatment or interventional nerve blocks. All the patients were diagnosed on the basis of signs, symptoms and MRI (CISS sequence). Anatomical landmarks of ophthalamic nerve, maxillary nerve, mandibular nerve were identified and nerve stimulation was done by placing the probe in the affected nerve division. Each point was stimulated with the radiofrequency probe kept for 10 minutes, giving a current of 10 to 30 milli-amperes with a set frequency of 2 Hertz. A total of 10 settings were given on alternate days. Assessment of pain relief, improvement, or deterioration was done using Barrow Neurological Institute Pain Intensity Score and Brief Pain Inventory facial scale scoring. Results: There was a significant reduction in pain scores observed on Barrow neurological institute (BNI) and Brief Pain Inventory-(BPI) pain intensity score (p value of <0.05) before and after pulsed radiofrequency (PRF) application. The duration of pain relief after the application of PRF was up to 180 days in 15 patients, 181-300 days in 8 patients and 300 to 600 days in 7 patients. Only 2 patients had a prolonged pain relief lasting for 601-720 days. One patient had developed exposure keratitis after 4 sittings of pulsed radiofrequency application at the supraorbital foramen. Conclusion: PRF offers short term relief in a majority of patients for a period of 18 months to 24 months. However, it was found that the long term effects of PRF may not be seen in patients with TN. PRF may be used as a short term measure for alleviating severe pain of TN till neurolytic blocks or a definitive surgery is carried out. [ABSTRACT FROM AUTHOR]

Postoperative pain following a septoplasty is expected to be mild and limited to a few days after the operation. Chronic pain following the procedure is rare. No cases of delayed-onset neuropathic pain or allodynia have been described in the literature. This paper presents a case of delayed-onset neuropathic pain after septoplasty in a previously pain-free asthmatic patient that was successfully managed by administration of intranasal local anaesthesia. Physical examination and imaging excluded any other cause of neuralgia. A literature review revealed reports of chronic pain in patients following septoplasty if there were nasal contact or compression points or nasal tumours. Separately, acute postseptoplasty allodynia is documented in iatrogenic maxillary nerve damage. However, delayed-onset neuralgic pain, exacerbated by certain environmental triggers, has not been previously described. Facial pain can be debilitating; successfully managing this neuralgic pain with administration of intranasal local anaesthetic had a substantial effect on the patient's quality of life. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate sphenoid sinus pneumatisation and its anatomical relation with adjacent neurovascular structures in Indian population. We performed a retrospective cross-sectional study, in which the pattern of sphenoid sinus pneumatization was studied on high-resolution computed tomography scans (n = 400), and association of the optic nerve, vidian canal and foramen rotundum along with related morphometric measurements were studied. Out of 400 CT scans, 60.5% were males. Majority had sellar type of pneumatization (89.5%) and single intersinus septum (68%). The most common configuration of relation of optic nerve canal was DeLano type 2 (34.75%). Vidian canal (VC) and Foramen rotundum (FR) were found dehiscent in 40.5% and 6.38% respectively. Average distance of FR from midline on right and left side was 16.3 ± 2.19 mm and 16.7 ± 2.23 mm respectively. Average distance of VC from midline on right and left side was 12.4 ± 5.84 mm and 12.4 ± 4.18 mm respectively. Average right FR to VC distance was 4.17 ± 2.16 mm and left FR to VC was 4.44 ± 2.20 mm. Anatomical variations of the sphenoid sinus are well known. In the present study, we have tried to highlight the importance of knowledge of various anatomical variations in relations to sphenoid sinus as they are critical in planning of surgery. Pre-operative radiological study and correlation is inevitable to assess type and extent of sinus pneumatisation, bony dehiscence and septal terminations to avoid injury to vital structures. [ABSTRACT FROM AUTHOR]

Background: The sphenoethmoidal cell and the sphenoid sinus (SS) show great similarity in endoscopy and imaging. Hence, it is important to accurately identify the sphenoethmoidal cell preoperatively to prevent injury of the nerve and artery during endoscopic surgery. The aim of the present study was to investigate a special type of sphenoethmoidal cell. Methods: A total of 365 inpatients whose paranasal sinus computed tomography (CT) was collected and reviewed from May 2018 to September 2019 were included. The anatomical imaging characteristics of the sphenoethmoidal cell were observed. Results: A special type of the sphenoethmoidal cell was found on 9 sides in 730 sides (1.3%), according to its extension to the SS. Unlike Onodi cell (49.6%) and Jinfeng cell (1.3%), this cell simultaneously extends toward the superolateral, lateral, and inferolateral regions of the SS and is simultaneously closely attached to the optic canal and the maxillary nerve. Presently, this cell is named as the whole lateral type of the sphenoethmoidal cell, and the SS is located at the medial or inferomedial of it. Conclusions: When evaluating the paranasal sinus CT preoperatively, attention must be paid to the possibility of the whole lateral type of sphenoethmoidal cell appearing, not just Onodi cell, extending into the SS. [ABSTRACT FROM AUTHOR]

Objective: The sphenoid sinus is a paranasal sinus that is extremely difficult to reach, being located deep in the skull and surrounded by a large number of vital neural and vascular structures. Additional radiological evaluation of the sphenoid sinus and related neurovascular structures is essential before surgery. This study aimed to analyze the anatomical variations associated with the neurovascular structures in and around the sphenoid sinus using multislice computed tomography (CT) and contribute to the literature by comparing the obtained data with previous studies. Material and Method: A total of 100 patients (50 females, 50 males) who underwent paranasal sinus CT for various rhinologic diseases were included in the study. Sphenoid sinus variations were evaluated as bone tissue anomalies and soft tissue pathologies on CT. Results: In this study, variations in the neurovascular borders of the sphenoid sinus were the most common findings. The variations related to the Vidian canal were most frequent with an incidence of approximately 73%, followed by those related to the optic nerve 55%, maxillary nerve 53%, and internal carotid artery 52%. Pneumatization of the pterygoid plate was observed in 59% of cases, pneumatization of the anterior clinoid process in 41%, and that of the greater wing of the sphenoid in 13%. Furthermore, 15% of the patients had onodi cells, 46% had multiple septations, 20% had mucosal thickening, 0.4% had polyps, and 0.3% had retention cysts. Conclusion: The structure of the sphenoid sinus is highly variable, and paranasal sinus CT is important in determining anatomic variations before sinonasal and transsphenoidal surgery and predicting possible complications during surgery. In this study, the variations of the sphenoid sinus were found at a higher rate compared to previous studies, which may be due to the differences in ethnic groups, CT imaging technique, or anatomical evaluation criteria. [ABSTRACT FROM AUTHOR]

Objective: To demonstrate the utility and limitations of the extradural endoscopic–assisted anterior temporal fossa approach to the pterygopalatine fossa (PPF), infratemporal fossa (ITF), paranasal sinuses (PS), parapharyngeal region (PPR), nasal cavities (NC), epipharynx (EP), and clivus. Methods: A frontotemporal orbitozygomatic craniotomy is performed. The dura is elevated from the cavernous sinus (CS). The anterior temporal fossa floor is drilled. Foramen rotundum and ovale are opened. The PPF is exposed and the lateral margin of inferior orbital fissure (IOF) is removed. The anterolateral triangle (ALT) is drilled and the vidian nerve (VN) is exposed. Drilling between the maxillary nerve (V2) and the VN provides access to the sphenoid sinus (SphS). The medial pterygoid plate is drilled exposing the EP. The maxillary sinus (MaxS) is opened anterior to the PPF. V2 is transposed laterally to enlarge the anteriomedial triangle (AMT). The orbital muscle of Muller is removed as well as the medial margin of the IOF, which opens the SphS. Anteriorly, the posterior ethmoid air cells are opened. Morphometric measurements evaluating the size of the ALT were done and the PS, NC, EP were explored with the endoscope. Results: The ALT and AMT triangle provides a wide exposure of the PPF, ITF, PPR. In addition, those triangles represent a deep entry point to explore the PS, NC, and EP. Conclusion: The ALT and AMT are useful corridors to access to the SphS, MaxS, PS, NC, and EP via a transcranial approach. The use of the endoscope through this corridor widely extend the extradural anterior temporal fossa approach which may be considered as a valuable alternative to the extended endoscopic endonasal approach for selected skull base lesions extending both intracranial and into the PS, NC and EP. [ABSTRACT FROM AUTHOR]

To study the morphometric location of the incisive, greater, and lesser palatine foramina for maxillary nerve block. Two hundred Thai dry skulls were randomly organized from the Forensic Osteology Research Center. The distances of the parameters were measured via Vernier caliper.: Thedistances from the incisive foramen to the incisive margin of the premaxilla were 10.93±2.42 mm in males and 10.98±2.06 mm in females. From the left side, the incisive foramen to the greater palatine foramen (GPF) was39.07±2.23mm in males and 38.57±2.41 mm in females, and from the right side were 39.81±2.37 mm in males and 38.62±2.53mm in females. From the left side, the incisive foramen to the lesser palatine foramen (LPF) was 43.16±2.23 mm in males and 41.84±2.42mm in females and from the right side were 42.93±2.14 mm in males and 41.76±2.61 mm in females. The GPF found at medial to the maxillary third molar were 94-95 % in males and 84 % in females. These findings suggest that the medial position to the third molar teeth be used as a landmark for a palatine nerve block in Thais. These findings will help dentists to perform local anesthetic procedures, especially the nasopalatine and greater palatine nerve blocks, more effectively. [ABSTRACT FROM AUTHOR]

Of the techniques visited in this literature review, the RBNB-SOF has the technique whereby accurate needle placement can most easily be identified and involves placement in a location with the fewest vulnerable structures. The ocular examination in horses with painful eyes is limited by their physicality and powerful orbicularis oculi muscles. The RBNB-4P and RBNB-MP/P techniques involve injection in the region of the orbital apex. [Extracted from the article]

To describe a novel in-plane ultrasound (U/S)-guided temporal approach to peribulbar block in dogs. Prospective experimental cadaver study. A group of 10 Beagle cadavers. After describing the U/S anatomy, peribulbar injection was performed bilaterally in 10 thawed Beagle cadavers by two randomly assigned operators. A 5–8 MHz microconvex U/S probe was positioned caudal to the orbital ligament in the longitudinal plane. Using an in-plane technique, methylene blue dye was injected in five dogs (10 eyes total), while methylene blue dye and iohexol contrast mixture (50:50) were injected in the remaining five dogs. Injection volume was 0.2 mL cm−1 of cranial length. A computed tomography (CT) scan was performed on dogs injected with dye and contrast to identify spread of contrast. Dissection to visualize dye spread in the orbit was performed in all dogs. Injection success was defined as spread of contrast into the peribulbar space. The pattern of distribution of contrast-dye was also assessed. Comparisons between operator and bilateral injections were assessed using a Student t test (p < 0.05). All other data are reported as number (n/N) and percentage (%). Peribulbar spread was noted in 19/20 injections (95%) on dissection. CT imaging (five dogs) illustrated peribulbar contrast spread in 9/10 injections (90%), with mixed peribulbar/retrobulbar spread for the remaining injection. Contrast was present at the rostral alar foramen in 4/10 (40%) injections, orbital fissure in 5/10 (50%), oval foramen in 1/10 (10%), maxillary nerve in 3/10 (30%) and intracranial in 5/10 (50%). Coverage of the maxillary nerve was noted on 3/20 (15%) injections on dissection. No further dye spread was noted. This technique demonstrated peribulbar spread of injectate in 100% of injections for the 10 canine cadavers studied. Further studies are required to evaluate this technique clinically. [ABSTRACT FROM AUTHOR]

​Purpose: Suprazygomatic maxillary nerve blocks (SMB) are used in adult and pediatric patients to provide analgesia for midface surgery and chronic maxillofacial pain syndromes. The ultrasound-guided SMB technique ensures visualisation of the needle tip, avoidance of the maxillary artery and confirmation of local anesthetic spread. The goal of this study was to correctly identify SMB sonoanatomical landmarks to ensure the nerve block is performed safely and effectively. Methods: Following an ultrasound-guided SMB with dye injection on 2 embalmed cadavers, pre-tragal face-lift style incision with a full thickness flap dissection was performed allowing accurate visualization of the bony landmarks being used for sonography and identification of the location of the injected dye. Results: This study identifies the correct sonoanatomic landmarks as the maxilla and the coronoid process of the mandible which suggests that the block needle tip and local anesthetic injection are within the infratemporal fossa as opposed to the previously reported pterygopalatine fossa. Conclusion: An improved understanding of the sonoanatomy will aid clinicians who are learning, performing and teaching the ultrasound-guided suprazygomatic approach to the maxillary nerve block. [ABSTRACT FROM AUTHOR]

OBJECTIVE To compare efficacy and duration of desensitization of oral structures with a lidocaine-bupivacaine mixture administered via a lateral percutaneous or modified infraorbital approach. ANIMALS 6 healthy adult hound-type female dogs. PROCEDURES In this crossover study, dogs were randomized for side (left or right) and maxillary nerve approach (lateral percutaneous or infraorbital), with a 2-week washout period. Dogs were anesthetized, and a 2-mL mixture of 2% lidocaine and 0.5% bupivacaine (50:50 [vol/vol]) was administered with a 22-gauge, 4.5-cm-long catheter inserted through the infraorbital canal (infraorbital approach) or with a shielded stimulating needle to the maxillary nerve (percutaneous approach). Reflex-evoked motor potentials were measured for the maxillary canine tooth, fourth premolar tooth, second molar tooth, and hard palate mucosa ipsilateral to the injected mixture and for the contralateral maxillary canine tooth (control) at three 10-minute intervals before injection (baseline) and at predetermined times after injection for up to 6.7 hours. For each oral structure, the proportion of dogs with desensitization (efficacy) and time to onset and duration of desensitization were compared between approaches. RESULTS The proportion of dogs with successful nerve blockade did not significantly differ between infraorbital and percutaneous approaches and among the 4 oral structures. Time to onset of desensitization did not differ between approaches, but duration was significantly longer with the infraorbital approach. CONCLUSIONS AND CLINICAL RELEVANCE A modified infraorbital approach with the lidocaine-bupivacaine mixture had similar effects to a lateral percutaneous approach but provided a longer duration of desensitization. Neither approach was universally successful at desensitizing all oral structures. [ABSTRACT FROM AUTHOR]

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. Prospective, blinded, randomized, crossover placebo-controlled study. Beagle dogs (five cadavers, nine live dogs), with a median (interquartile range) weight of 10.5 (10.3–11.0) kg. 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). 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. Concurrent injections of lidocaine at the maxillary and ethmoidal foramina attenuated HR, arterial pressure and f R responses to nasal stimulation in Beagle dogs. [ABSTRACT FROM AUTHOR]

Although the etiology of classical trigeminal neuralgia is clearly understood to be neurovascular compression, the exact etiology of trigeminal neuralgia with continuous pain is often unknown. Mild sphenoid sinusitis is not usually considered to induce trigeminal neuralgia, especially when limited to the maxillary nerve. We report a rare case of trigeminal neuralgia of the maxillary nerve caused only by mild sphenoid sinusitis and discuss the significance of the anatomical structure and diagnostic procedures. A 45-year-old woman noticed a sudden onset of temporal pain followed by numbness on her right cheek. Her right gingiva also experienced sensory disturbance. The symptoms gradually subsided after the initial onset, but they persisted. She visited our hospital for further examinations and had no febrile episodes throughout the course. A tingling sensation and sensory disturbance were only identified in the maxillary nerve. No other neurological symptoms were noted. Magnetic resonance imaging revealed mild sphenoid sinusitis on the right side. The absence of the bony boundary between the sphenoid sinus and maxillary nerve was revealed using thin-sliced computed tomography (CT). The patient's symptoms were diagnosed as maxillary neuropathy caused by mild sinusitis. The bony defect around the maxillary nerve was considered to have affected development of the pathological process. Even mild sphenoid sinusitis can cause inflammation to spread to the maxillary nerve if no bony boundary exists between it and the sphenoid sinus. A coronal CT study is highly beneficial for clarifying the pathophysiological mechanism of trigeminal neuralgia limited to the maxillary nerve. [ABSTRACT FROM AUTHOR]

Immunoglobulin G4-related optic neuropathy caused by optic perineuritis is a rare complication of immunoglobulin G4-related disease (IgG4-RD). Herein, we report a 38-year-old Asian man with history of sinusitis who presented with painless blurred vision and proptosis for over 6 months. Examination with the Hertel exophthalmometer revealed 21.5 mm on both eyes. Magnetic resonance imaging revealed a doughnut sign encircling the right optic nerve, bilateral tram-track signs on both optic nerves, enlarged bilateral maxillary nerves with perineural spreading to the infraorbital nerves, hypertrophy of extraocular muscles, and pansinusitis. Visual evoked potentials displayed bilateral delayed P100 latency, indicating bilateral optic neuropathy. Biopsy with functional endoscopic sinus surgery demonstrated diffuse dense lymphoplasmacytic infiltrate and fibrosis. IgG4-positive plasma cells exceeded 50 cells per high-power field while the overall IgG4/IgG ratio was above 40%. Serological studies unveiled extremely high serum concentrations of IgG4 (2650 mg/dL), and the calculated serum IgG4/IgG ratio was 100%. These comprehensive features supported the diagnosis of IgG4-RD with bilateral optic perineuritis, branches of trigeminal nerve involvement, and pansinusitis. The visual acuity improved slightly following the initiation of treatment with corticosteroids, but it became worse again during the tapering course. Following another course of corticosteroids followed by subsequent immunosuppressant treatment with azathioprine, vision in both eyes ultimately improved during the 2-year follow-up period. [ABSTRACT FROM AUTHOR]

OBJECTIVE To investigate use of a candidate maxillary nerve block in rabbits. ANIMALS 13 healthy New Zealand White rabbits (Oryctolagus cuniculus). PROCEDURES In phase I, the maxillary nerve block procedure was performed in 7 sedated rabbits with 2 volumes (0.25 and 0.5 mL) of a saline (0.9% NaCI)-tissue marker dye solution (I injection/side by random assignment). Rabbits were euthanized and dissected; numeric scales were used to rate injection accuracy and extent of staining. In phase 2, the nerve block was performed with articaine hydrochloride-epinephrine solution (0.5 mL) on a randomly assigned side in 6 sedated rabbits, with the contralateral side used as a control. Sensory function of the relevant dermatome was tested in triplicate with an algesiometer 0, 30, and 90 minutes after recovery from sedation. Statistical methods were used to compare results between injection volumes (phase I) and between treated and control sides (phase 2). RESULTS In phase I, dye was in contact with the targeted nerve after 13 of 14 injections. Accuracy and extent of staining did not differ significantly between volumes. In phase 2, algesiometer-applied force tolerance differed significantly between treated and control sides 30 minutes after recovery from sedation (56 to 145 minutes after the nerve block procedure). No adverse effects were detected in either study phase. CONCLUSIONS AND CLINICAL RELEVANCE The described technique for a maxillary nerve block was accurate and effective for desensitization of the relevant dermatome as assessed by algesiom- etry in healthy rabbits. Additional studies are needed to assess use of this procedure in rabbits of other breeds and its efficacy for clinical use. [ABSTRACT FROM AUTHOR]

Introduction: Trigeminal neuralgia is described as severe, stabbing unilateral pain along the distribution of trigeminal nerve branches. The three subtypes include- Classical, secondary and idiopathic. Aim: To study the clinical profile, presentation and radiological imaging features in trigeminal neuralgia patients. Materials and Methods: This cross-sectional study included outpatient medical records of 60 trigeminal neuralgia patients between June 2015 to June 2020 (five years) in a Tertiary care Medical College Hospital. Various parameters studied were: (a) Age; (b) Gender; (c) Dental treatment; (d) Pain severity; (e) Trigger factors; (f) Side and branch involved; (g) Sensory abnormalities; (h) MRI. Data was entered in Microsoft excel and analysed using SPSS statistical software 20.0. Chi-square test was used for categorical variables. Results: Among the 60 patients studied, the common demographic and clinical features were as follows: 34 were females (56.7%); 36 with right side presentation (60%); 25 had maxillary nerve division distribution (41.7%); 57 patients experienced shock/lancinating pain (95%); and 40 had numeric pain severity scale of 4-6 (66.7%). Classical Trigeminal Neuralgia was the most common subtype seen in 31 patients (51.7%). Involvement of dual divisions (maxillary and mandibular), absence of trigger factors and presence of hypoesthesia were more suggestive of Secondary Trigeminal Neuralgia (p<0.05). Based on MRI imaging, 31 (51.7%) showed neurovascular compression with atrophy or displacement of trigeminal nerve root. Only 5 (8.4%) had secondary causes (schwannoma, meningioma, demyelination, infarct). Conclusion: The key clinical features of trigeminal neuralgia include female preponderance, right side presentation, maxillary nerve division distribution, shock/lancinating pain with touch and breeze as common trigger factors. As some of them had a previous dental treatment or procedure, dentists need to be aware of this entity. Certain clinical features would help to differentiate the secondary from classic and idiopathic neuralgia subtype. [ABSTRACT FROM AUTHOR]

Background: For children with cleft palates, surgeries at a young age are necessary to reduce feeding or phonation difficulties and reduce complications, especially respiratory tract infections and frequent sinusitis. We hypothesized that dexmedetomidine might prolong the postoperative analgesic duration when added to bupivacaine during nerve blocks. Methods: Eighty patients of 1-5 years old were arbitrarily assigned to two equal groups (forty patients each) to receive bilateral suprazygomatic maxillary nerve blocks. Group A received bilateral 0.2 mL/kg bupivacaine (0.125%; maximum volume 4 mL/side). Group B received bilateral 0.2 mL/kg bupivacaine (0.125%) + 0.5 µg/kg dexmedetomidine (maximum volume 4 mL/side). Results: The modified children's hospital of Eastern Ontario pain scale score was significantly lower in group B children after 8 hours of follow-up postoperatively (P < 0.001). Mean values of heart rate and blood pressure were significantly different between the groups, with lower mean values in group B (P < 0.001). Median time to the first analgesic demand in group A children was 10 hours (range 8-12 hr), and no patients needed analgesia in group B. The sedation score assessment was higher in children given dexmedetomidine (P = 0.03) during the first postoperative 30 minutes. Better parent satisfaction scores (5-point Likert scale) were recorded in group B and without serious adverse effects. Conclusions: Addition of dexmedetomidine 0.5 µg/kg to bupivacaine 0.125% has accentuated the analgesic efficacy of bilateral suprazygomatic maxillary nerve block in children undergoing primary cleft palate repair with less postoperative supplemental analgesia or untoward effects. [ABSTRACT FROM AUTHOR]

Summary: The objective of this study was to investigate the distribution pattern of two different volumes of a mepivacaine 2%/iopromide mixture along the infraorbital nerve using a controlled injection pressure. Infraorbital nerve blocks were performed at the infraorbital foramen with two different volumes (group 10: 10 mL or group 15: 15 mL) using a 22 gauge, 3 cm long needle and a standardised injection pressure in 10 cadaver skulls. Ten minutes after injection, computed tomography was performed in all skulls. Images were analysed for needle position, length of the iopromide column, filling percentage of the infraorbital canal, presence of iopromide at the maxillary foramen, volume of leakage, length and angle of the infraorbital canal and pathological changes. Percentage of infraorbital canal filling ranged from 74% ± 0.23 to 86.9% ± 0.24 and iopromide was present at the maxillary foramen in 70–90% of the blocks of groups 15 and 10 respectively; neither variables differed significantly between groups 15 and 10 (P = 0.582 and P = 0.244 respectively). Mean leakage retrograde into the rostrally surrounding tissue and into the maxillary sinus was significantly greater in group 15 (7.9 cm3 ± 4.2) than group 10 (3.02 cm3 ± 3.13), P = 0.008. Older horses were significantly associated with higher filling percentages (P = 0.049), whereas filling percentages or whether the mixture reached the maxillary foramen were not associated with any of the other variables. Infraorbital nerve blocks using 10 and 15 mL result in complete filling of the infraorbital canal in the majority of horses. This block may result in sufficient analgesia of Triadans 06 to 11 and offer a suitable safe alternative to maxillary nerve blocks. [ABSTRACT FROM AUTHOR]

The anterior part of the base of cranium has the hard palate formed by the palatine process of the maxillary bone anteriorly and the horizontal plate of palatine bone posteriorly. At the posterior part of palatine bone medial to the maxillary alveolar arch two foramina are present. They are the larger greater palatine foramen and a smaller lesser palatine foramen. Greater Palatine Foramen (GPF) is located medial to the upper third molar tooth and may vary with the sutural growth occurring between palatine and maxillary bones. The precise knowledge about the morphometry of greater palatine foramen is essential for the clinicians while performing the maxillary nerve block, failure of which leads to the damage of the greater palatine nerve. Sixty adult dry human skull bones irrespective of sex and age were studied. The position, shape, direction and distance of greater palatine foramen with its variations were noted on both sides. The mean value of the diameter of the right side greater palatine foramen was 3.93 ± 0.12 mm. The mean value of the diameter of the left side greater palatine foramen was 4.16 ± 0.19 mm. The present study may be helpful for the clinicians to locate greater palatine foramen for giving local anaesthesia in molar tooth extraction, palatal surgeries and also helps to avoid post extraction haemorrhage of greater palatine vessels. [ABSTRACT FROM AUTHOR]

Objectives: The "nociceptive-specific" blink reflex (nBR) evoked by extraoral stimulation has been used to assess trigeminal nociceptive processing in patients with trigeminal nerve damage regardless of the site of damage. This study aimed to test the feasibility of nBR elicited by intraoral stimulation, compare intraoral and extraoral nBR and assess the intrarater and interrater reliability of the intraoral nBR for the maxillary (V2) and mandibular (V3) branches of the trigeminal nerve. Materials and methods: In 17 healthy participants, nBR was elicited by stimulation of two extraoral and two intraoral sites by two operators and repeated intraorally by one operator. Main outcome variables were intraoral stimulus-evoked pain scores and nBR R2 responses at different stimulus intensities. Intraclass correlation coefficients (ICC) were used to assess reliability. Results: Dependent on the stimulus intensity, intraoral stimulation evoked R2 responses in up to 12/17 (70.6%) participants for V2 and up to 8/17 (47.1%) participants for V3. Pain scores (p < 0.003) and R2 responses (p < 0.004) increased with increasing intensities for V2, but not V3. The R2 responses were significantly smaller with intraoral stimulation compared to extraoral stimulation (p < 0.014). Overall, ICCs were fair to excellent for V2 but poor for V3. Conclusion: Intraorally evoked nBR was feasible in a subset of healthy participants and was less responsive than nBR with extraoral stimulation. The V2 nBR showed better reliability than V3. Clinical relevance: The nBR can be used to assess nerve damage to the maxillary intraoral regions, though other measures may need to be considered for the mandibular intraoral regions. [ABSTRACT FROM AUTHOR]

Background: Surgical access to the second (V2, maxillary) and third (V3, mandibular) branches of the trigeminal nerve (V) has been classically through a transoral approach. Increasing expertise with endoscopic anatomy has achieved less invasive, more efficient access to skull base structures. The authors present a surgical technique using an endoscopic endonasal approach for the treatment of painful V2 neuropathy. Methods: Endoscopic endonasal dissections using a transmaxillary approach were performed in four formalin-fixed cadaver heads to expose the V2 branch of the trigeminal nerve. Relevant surgical anatomy was evaluated and anatomic parameters for neurectomy were identified. Results: Endoscopic endonasal transmaxillary approaches completed bilaterally to the pterygopalatine and pterygomaxillary fossae exposed the V2 branch where it emerged from the foramen rotundum. The anatomy defined for the location of neurectomy was determined to be the point where V2 emerged from the foramen rotundum into the pterygopalatine fossa. The technique was then performed in 3 patients with intractable painful V2 neuropathy. Conclusions: In our cadaveric study and clinical cases, the endoscopic endonasal approach to the pterygopalatine fossa achieved effective exposure and treatment of isolated V2 painful neuropathy. Important surgical steps to visualize the maxillary nerve and its branches and key landmarks of the pterygopalatine fossa are discussed. This minimally invasive approach appears to be a valid alternative for select patients with painful V2 trigeminal neuropathy. [ABSTRACT FROM AUTHOR]