Transmaxillary approach for resection of maxillary division trigeminal schwannoma at foramen rotundum.

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.

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.

Duplication of the foramen rotundum: A rare case report.

Variations at the skull base can result in misinterpretation of radiological imaging and occasionally, iatrogenic injury. Here, we describe, to our knowledge, the second reported case of a duplicated foramen rotundum. The morphometrics of this finding are documented and the anatomy and potential clinical consequences of such an anatomical variation discussed. Such a finding is of archival value. Additionally, foramen rotundum duplication such as found in our case might also lead to complications while using, for example, transsphenoid approaches to the middle cranial fossa as well as various transfacial treatments for trigeminal neuralgia which rely on observing the foramina around the foramen ovale on fluoroscopy for correct positioning of needles and catheters.

Enhanced recovery after cleft palate repair: A quality improvement project.

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.

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

OBJECTIVES: Does clonidine, as adjuvant to bupivacaine for suprazygomatic maxillary nerve blocks, reduce emergence agitation in patients undergoing cleft lip and cleft palate surgery? DESIGN: Randomized, controlled, and double-blind study. SETTING: Guwahati Comprehensive Cleft Care Center, Guwahati (Assam, India). PARTICIPANTS: A total of 124 patients; with a median age of 5 years in the clonidine group (CLG) and 7 years in the control group (CG), who underwent cleft lip or cleft palate surgery were included. Exclusion criteria included lack of consent from patients or their guardians, allergy to local anesthetics, coagulation disorders, local infection at the puncture site before performing the block, and language difficulties or cognitive disorders. INTERVENTIONS: Patients were randomized into 2 groups to receive bilateral suprazygomatic maxillary nerve blocks with either a bupivacaine/clonidine mixture for the CLG or bupivacaine alone in the CG. MAIN OUTCOME MEASURE: The primary end point was the incidence of emergence agitation. RESULTS: There was a statistically significant difference in the incidence of emergence agitation (30.2% in the CG compared to 15.2% in the CLG; difference of incidences: 15%, 95% CI: 0.1-30.1). The percentage of patients requiring intraoperative Fentanyl was lower in the CLG (10.6% compared to 26.4%; difference of incidences: 15.8%, 95% CI: 1.8-29). No other differences were observed. Further research in a more typically aged children population undergoing cleft surgery is needed. CONCLUSIONS: The use of clonidine as an adjuvant to bupivacaine in maxillary nerve block reduces the incidence of emergence agitation and intraoperative opioid consumption without hemodynamic or sedative side effects in patients undergoing cleft lip and palate surgery.

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

OBJECTIVE: To describe an approach for ethmoidal nerve block (EBLOCK) and to compare the effects of a maxillary nerve block (MBLOCK), EBLOCK and their combination (M-EBLOCK) on heart rate (HR), systolic (SAP), mean (MAP), diastolic (DAP) arterial pressures and respiratory rate (fR) during nasal stimulation in dogs. STUDY DESIGN: Prospective, blinded, randomized, crossover placebo-controlled study. ANIMALS: Beagle dogs (five cadavers, nine live dogs), with a median (interquartile range) weight of 10.5 (10.3-11.0) kg. METHODS: The accuracy of iohexol injections (each 1 mL) at the maxillary and ethmoidal foramina in cadavers was evaluated using computed tomography. Then, anesthetized dogs were administered four bilateral treatments separated by 1 week, saline or 2% lidocaine 1 mL per injection: injections of saline at the maxillary and ethmoidal foramina (Control), injections of lidocaine at the maxillary foramina and saline at the ethmoidal foramina (MBLOCK), injections of saline at the maxillary foramina and lidocaine at the ethmoidal foramina (EBLOCK) and injections of lidocaine at all foramina (M-EBLOCK). The ventral nasal meatus was bilaterally stimulated using cotton swabs, and HR, SAP, MAP, DAP and fR were continuously recorded. Values for each variable were compared before and after stimulation using Wilcoxon signed-rank test. Changes in variables among treatments were analyzed using Mann-Whitney U and Kruskal-Wallis tests (p ≤ 0.05). RESULTS: Computed tomography revealed iohexol distribution around the openings of the target foramina in all cadavers. In living dogs, HR, SAP, MAP, DAP and fR significantly increased after stimulation within each treatment (p < 0.03). Physiologic responses were significantly attenuated, but not absent, in the M-EBLOCK [HR (p = 0.019), SAP, MAP, DAP and fR (all p ≤ 0.001)] compared with those in the Control. CONCLUSIONS AND CLINICAL RELEVANCE: Concurrent injections of lidocaine at the maxillary and ethmoidal foramina attenuated HR, arterial pressure and fR responses to nasal stimulation in Beagle dogs.

Suprazygomatic maxillary nerve block: an ultrasound and cadaveric study to identify correct sonoanatomical landmarks.

​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.

Variant neurovascular relations of the sphenoid sinus in adult Nigerians.

BACKGROUND: With the advent of endoscopic sinus surgery, the variant neurovascular relations of the sphenoid sinus are important to surgeons to minimise the iatrogenic complications. This study elucidates the variant neurovascular relations of the sphenoid sinus in adult Nigerians. MATERIALS AND METHODS: This study was conducted at the Radiology Department of Delta State University Teaching Hospital after institutional approval. Brain computed tomography images of 336 patients, aged ≥20 years and spanning over 5 years' duration were utilised. We evaluated the sphenoid sinus for protrusion and dehiscence of neurovascular structures bilaterally. The position of the optic nerve in relation to the sinus was classified from Type 0-4. The Statistical Package for the Social Sciences software version 23 was used for the data analysis. The Chi-square test was used to probe for the association between the variants with regard to side and gender. P < 0.05 was considered statistically significant. RESULTS: Dehiscence and protrusion of the internal carotid artery (ICA) occurred in 34, 10.1% and 83, 24.7% patients correspondingly. The dehiscence of optic, maxillary and Vidian nerves was (26, 7.7%), (60, 17.9%), and (53, 15.8%), whereas the frequency of their protrusion was (50, 14.9%), (76, 22.6%) and (87, 25.9%), respectively. All these variants except the ICA and maxillary nerve dehiscence showed a significant association with the side of occurrence (P = 0.001). Out of the 672 optic canals evaluated bilaterally, a preponderance of Type I (534, 79.5%) was observed followed by II (96, 14.3%), IV (35,5.2%), III (7, 1.0%) and Type 0 (0, 0%). CONCLUSION: Our study has shown that the neurovascular relations of the sphenoid sinus vary from previously documented reports, thus confirming the need for pre-operative evaluation.

Location of the infraorbital foramen with reference to soft tissue landmarks for regional nerve blocks during midface surgery.

PURPOSE: An infraorbital nerve (ION) block is widely used to accomplish regional anesthesia during surgical procedures involving the midface region. This study aimed to elucidate the exact location of the infraorbital foramen (IOF) in relation to clinically useful soft-tissue landmarks for achieving an effective ION block. METHODS: Forty-three hemifaces from 23 embalmed Korean cadavers were dissected. The lateral canthus, peak of Cupid's bow, medial limbus, and midline were used as reference points. The distances from the IOF to the midline and the lateral canthus were measured. RESULTS: The IOF was located approximately 25 mm below the lateral canthus and 27 mm lateral to the midline. In all cases, the IOF was situated within 9.0 mm of the crossing point of the oblique line connecting the lateral canthus to the peak of Cupid's bow and the vertical line through the medial limbus. CONCLUSION: Considering the spread of an anesthetic agent, injecting it into the crossing point of the oblique line through the lateral canthus to the peak of Cupid's bow and the vertical line through the medial limbus would successfully block the ION in most patients.

Standing Sedation and Iocoregional Analgesia in Equine Dental Surgery.

Procedural sedation has become popular for describing a semiconscious state that allows patients to be comfortable during certain surgical or diagnostic procedures. Sedation may be enhanced by locoregional anesthetic techniques to produce sufficient analgesia and muscle relaxation for surgery to occur. Sedation and local anesthesia for standing diagnostic and surgical procedures on the horse's head circumvents the potential complications of general anesthesia (particularly, complications related to recovery). However, the implementation of a locoregional anesthetic technique requires a thorough understanding of the anatomy to maximize success and minimize possible complications.

Long-term Follow-up of Patients Treated with Percutaneous Radiofrequency Thermocoagulation via the Foramen Rotundum for Isolated Maxillary Nerve Idiopathic Trigeminal Neuralgia.

OBJECTIVE: The purpose of this study is to evaluate the effectiveness and safety of percutaneous radiofrequency thermocoagulation (PRT) via the foramen rotundum (FR) for the treatment of isolated maxillary (V2) idiopathic trigeminal neuralgia (ITN) and assess the appropriate puncture angle through the anterior coronoid process to reach the FR. METHODS: Between January 2011 and October 2016, 87 patients with V2 ITN refractory to conservative treatment were treated by computed tomography (CT)-guided PRT via the FR at our institution. The outcome of pain relief was assessed by the visual analog scale (VAS) and Barrow Neurological Institute (BNI) pain grade and grouped as complete pain relief (BNI grades I-III) or unsuccessful pain relief (BNI grades IV-V). Recurrence and complications were also monitored and recorded. The puncture angle for this novel approach was assessed based on intraoperative CT images. RESULTS: Of the 87 treated patients, 85 (97.7%) achieved complete pain relief, and two patients (2.3%) experienced unsuccessful pain relief immediately after operation. During the mean follow-up period of 44.3 months, 15 patients (17.2%) experienced recurring pain. No severe complications occurred, except for hypoesthesia restricted to the V2 distribution in all patients (100%) and facial hematoma in 10 patients (11.5%). The mean puncture angle to reach the FR was 33.6° ± 5.7° toward the sagittal plane. DISCUSSION: CT-guided PRT via the FR for refractory isolated V2 ITN is effective and safe and could be a rational therapy for patients with V2 ITN.

Ophthalmic complications following ocular penetration during routine dentistry in 13 cats.

CASE HISTORY Thirteen cats developed ophthalmic complications following dental procedures in Australia and New Zealand between December 2014 and February 2018. All cats had at least one maxillary tooth extracted and some received a transoral maxillary nerve block. CLINICAL FINDINGS Ocular signs were identified at a median of 1.5 (min 0, max 14) days following elective dental procedures and included fibrin in the anterior chamber, aqueous flare, vision loss and miosis. Response to medical management was poor overall, with 7/13 (54%) cats undergoing subsequent enucleation and one cat was subjected to euthanasia shortly after the dental procedure due to ocular disease. The remaining five cats were managed medically. Of these, four exhibited signs of persistent inflammation at the last ophthalmic assessment, and one was subsequently subjected to euthanasia due to reasons unrelated to ocular health. Active inflammation resolved in one cat, however the lesions caused by previous inflammation persisted. PATHOLOGICAL FINDINGS Assessment of six enucleated globes showed a variety of pathological changes, with marked fibrinous exudation and suppurative inflammation as predominant features. A scleral penetration site was identified in three globes. Four globes had lens capsule rupture and phacoclastic uveitis. DIAGNOSIS Endophthalmitis following iatrogenic globe penetration during routine dental procedures. CLINICAL RELEVANCE This case series demonstrates that globe penetration during dental procedures carries a poor prognosis for the eye. Clinicians should be aware of the risks of ocular trauma during dental procedures in cats and great care should be taken to avoid ocular penetration, particularly during tooth extractions. Transoral maxillary nerve blocks should be avoided or used with extreme caution in cats.

Morphometric evaluation and clinical implications of the greater palatine foramen, greater palatine canal and pterygopalatine fossa on CBCT images and review of literature.

INTRODUCTION: The pterygopalatine fossa (PPF) infiltration is performed to reduce blood flow during endoscopic sinus surgery and septorhinoplasty, as well as to control posterior epistaxis and provide regional anesthesia in dental procedures. PPF infiltration performed with consideration of the morphometrics of greater palatine foramen (GPF), greater palatine canal (GPC) and PPF would increase the success of the procedure and reduce the risk of complications. The aim of this study is to investigate the GPF, GPC, lesser palatine foramen (LPF), lesser palatine canal (LPC) and PPF morphology via the images obtained by CBCT, to provide information for interventional procedures. MATERIALS AND METHODS: GPF, GPC, LPF, LPC and PPF were morphometrically evaluated retrospectively in CBCT images of 75 female and 75 male cases by Planmeca Romexis program. The 19 parameters were measured on these images. RESULTS: These parameters were evaluated statistically. The comparison of these parameters by genders revealed significant differences in distances between GPC-PC, PC-IOF, LPC-GPF, GPF-MS in the coronal and transverse planes, the distance between GPF and the occlusal plane of the teeth, GPF-PNS, GPF-IF and TD-GPF, and in the area of GPF. The number of LPF was found ranging from 1 to 5. CONCLUSION: Our results may help to insert to needle properly for application of maxillary nerve block with a high success rate and minimal complication. We recommend that the needle should be inserted 14-15 mm lateral to the midsagittal plane, 19-20 mm over the occlusal plane of the teeth and on the same line with the third molar teeth. For PPF infiltration through the GPF, the needle should be pushed forward 28 mm upward at 66° angle on the transverse plane and 14°-15° angle on the vertical plane.

Previously undescribed palpebral branch from the infraorbital canal: Application to surgery of the eyelid and treatment of orbital floor fractures.

The sensory innervation of the inferior eyelid is mainly derived from the inferior palpebral branch (IPb) of the infraorbital nerve (ION). This study aimed to investigate another, to our knowledge, previously unknown branch, and elucidate its location and distribution. Twelve sides from seven fresh frozen cadaveric Caucasian heads were used in this study. The specimens were derived from two male and four female adult cadavers age. The diameter of the IPb of the ION (D1) and branch arising from the upper wall of the infraorbital canal (D2), and distance between the branching points of this branch and the anterior border of the orbit floor (L1) was measured. A branch to the lower eyelid was found arising from the infraorbital canal on the majority of sides. D1 ranged from 0.4 to 1.1 mm. The branch arising from the upper wall of the infraorbital canal was found 10 sides (83%). D2 ranged 0.6 to 1.0 mm. L1 ranged from 10.2 to 19.8 mm. All of the branches arising from the upper wall of the infraorbital canal (10 sides) primarily innervated to the inferior eyelid. We suggest this branch should be named the "posterior IPb" of the ION. Knowledge of this branch might decrease sensory loss following invasive procedures of the lower orbit. Clin. Anat. 30:835-838, 2017. © 2017Wiley Periodicals, Inc.

A transorbital approach to the maxillary nerve block in dogs: a cadaver study.

OBJECTIVE: To describe a transorbital approach to the maxillary nerve block in dogs and compare it with a traditional approach. STUDY DESIGN: Prospective, randomized controlled study. ANIMALS: Heads from 17 euthanized dogs (10 Greyhounds, three Border Collies and four of mixed breed). METHODS: A volume of 1 mL of methylene blue dye was injected by each of two techniques, a traditional percutaneous approach and a transorbital approach to the maxillary nerve block. Both techniques were used on each head, alternating the left and right sides after random assignment to the first head. The heads were dissected to reveal the maxillary nerve and the length of nerve stained was measured. RESULTS: There was no significant difference (p = 0.67) in the proportion of nerves stained for a length >6 mm by either technique (88.2% transorbital versus 82.3% percutaneous). The mean length of nerve stained did not differ significantly between the techniques (p = 0.26). CONCLUSIONS AND CLINICAL RELEVANCE: The transorbital approach to the maxillary nerve block described here presents a viable alternative to the traditional percutaneous approach. Further study is required to confirm its efficacy and safety under clinical conditions.

Maxillary nerve blocks in horses: an experimental comparison of surface landmark and ultrasound-guided techniques.

OBJECTIVE: The aim of this preliminary proof-of-concept study was to evaluate and compare the success and complication rate of infiltration of the maxillary nerve of cadaver heads using previously described surface landmarks, standard ultrasound and a novel needle guidance positioning ultrasound system (SonixGPS). STUDY DESIGN: Prospective, anatomical, method-comparison study. ANIMALS: Thirty-eight equine cadaver heads. METHODS: Twenty-six veterinary students performed the three methods consecutively on cadaver heads using an 18 gauge, 8.9 cm spinal needle and 0.5 mL iodinated contrast medium. Computed tomography was used to quantify success (deposition of contrast in contact with the maxillary nerve) and complication rate (contrast identified within surrounding vasculature or periorbital structures) associated with each method. RESULTS: Perineural injection of the maxillary nerve was attempted 76 times, with an overall success rate of 65.8% (50/76) and complication rate of 53.9% (41/76). Success rates were 50% (13/26) with surface landmark, 65.4% (17/26) with standard ultrasound guidance and 83.3% (20/24) with SonixGPS guidance approaches (Fisher's exact test, p=0.046). No significant difference in complication rate was found between the three methods. CONCLUSIONS: Ultrasound-guided maxillary nerve blocks were significantly more successful than surface landmark approaches when performed by inexperienced operators, and the highest success rate was achieved with guidance positioning system (GPS) needle guidance. CLINICAL RELEVANCE: Local anaesthesia of the equine maxillary nerve in the fossa pterygopalatina is frequently used for diagnostic and surgical procedures in the standing sedated horse. Due to vague superficial landmarks with various approaches and the need for experience via ultrasound guidance, this block remains challenging. GPS guidance may improve reliability of maxillary and other nerve blocks, and allow a smaller volume of local anaesthetic solution to be used, thereby improving specificity and reducing the potential for side effects.

Anatomical characteristics of greater palatine foramen: a novel point of view.

PURPOSE: Anatomy of greater palatine foramen is important for maxillary nerve blocks, haemostatic procedures, and the treatment of neuralgia; although metrical data are available about its collocation, still several aspects need to be explored, such as the influence of the cranium size. METHODS: The position of greater palatine foramen was assessed on 100 skulls through six measurements (distances from intermaxillary suture, posterior palatal border, posterior nasal spine, and incisive foramen; palatal length; relative position on palatal length) and two angles (angles at incisive foramen and greater palatine foramen). Maximum cranial length, maximum cranial breadth, cranial height and bizygomatic breadth, horizontal cephalic index, and Giardina Y-index were evaluated. Possible differences according to sex and side were assessed through two-way ANOVA (p < 0.05). Measurements showing sexual dimorphism were further assessed through one-way ANCOVA including cranial parameters as covariates (p < 0.05). RESULTS: Distances of the greater palatine foramen from intermaxillary suture, incisive foramen, posterior palatal border, posterior nasal spine, palatal length, and position of the greater palatine foramen on the palatal length were statistically different according to sex (p < 0.05), independently from general cranial dimensions but for the distance from the posterior palatal border. The angle at the incisive foramen and distances from intermaxillary suture and from posterior nasal spine showed statistically significant differences according to side (p < 0.05). CONCLUSIONS: Results highlight that most of sexually dimorphic measurements useful for pinpointing the greater palatal foramen do not depend upon the cranium size. A more complete metrical assessment of the localization of the greater palatine foramen was provided.

Regional Nerve Blocks for Equine Dentistry.

Regional nerve blocks are necessary to facilitate equine oral surgery in the standing sedated patient. Step-by-step instruction on how to perform common regional nerve blocks are discussed, including infraorbital, maxillary, middle mental, and inferior alveolar nerve blocks. Regional nerve blocks are critical when performing dental procedures in the standing horse.1 The infraorbital and maxillary nerve blocks provide anesthesia of the infraorbital nerve, which is a branch of the maxillary nerve. Both nerve blocks provide adequate anesthesia for all maxillary dental procedures.1 When the infraorbital nerve block is utilized, care must be taken to advance the needle into the infraorbital foramen in order to appropriately anesthetize the caudal maxillary teeth. Mandibular dental procedures require anesthesia of the inferior alveolar nerve, which is a branch of the mandibular nerve. Local anesthesia at the level of the mental foramen will result in anesthesia of ipsilateral incisors and canines, while anesthesia at the level of the mandibular foramen will anesthetize the entire ipsilateral mandibular dental quadrant. All nerve blocks should have the injection site aseptically prepared prior to the procedure. The 4 most common dental nerve blocks are described step by step.

Infraorbital canal bilaterally replaced by a lateroantral canal.

The infraorbital canal (IOC) normally courses above the maxillary sinus in the orbit floor. During a retrospective study of cone beam computed tomography (CBCT) scans, we found a previously unknown variant of the IOC. The IOCs were absent, being replaced by lateroantral canals coursing around and not above the maxillary sinus to open at infraorbital foramina which were located above the second upper premolar teeth. On coronal multiplanar reconstructions, the lateroantral canals were located anatomically at the outer limit of the zygomatic recess of each maxillary sinus, while the upper wall of the sinus was devoid of any canal. Such rare variant should be kept in mind by dental practitioners and surgeons, as it can determine modifications of common procedures. In this regard, the anatomy of maxilla, as well as mandible, should be evaluated in CBCT on a case-by-case basis.

Microsurgical anatomy of the trigeminal nerve.

The objective of this study is to review surgical anatomy of the trigeminal nerve. We also demonstrate some pictures involving the trigeminal nerve and its surrounding connective and neurovascular structures. Ten adult cadaveric heads were studied, using a magnification ranging from 3× to 40×, after perfusion of the arteries and veins with colored latex. The trigeminal nerve is the largest and most complex of the cranial nerves. It serves as a major conduit of sensory input from the face and provides motor innervation to the muscles of mastication. Because of its size and complexity, it is essential to have thorough knowledge of the nerve before diagnoses and treatment of the pathologic processes in the orofacial, temporomandibular, infratemporal, and pterygopalatine areas. The trigeminal nerve is encountered with imaging or surgery of the skull base surgery. Thus, a comprehensive knowledge of the anatomy of the trigeminal nerve is crucial for performing the surgical procedures without significant complication.