Search

Objective: Percutaneous treatments for trigeminal neuralgia are safe, simple, and effective for achieving good pain control. Procedural risks could be minimized by using noninvasive imaging techniques to improve the placement of the radiofrequency thermocoagulation probe into the trigeminal ganglion. Positioning of a probe is crucial to maximize pain relief and to minimize unwanted side effects, such as denervation in unaffected areas. This investigation examined the use of laser speckle imaging during probe placement in an animal model., Methods: This preclinical safety study used nonhuman primates, Macaca nemestrina (pigtail monkeys), to examine whether real-time imaging of blood flow in the face during the positioning of a coagulation probe could monitor the location and guide the positioning of the probe within the trigeminal ganglion., Results: Data from 6 experiments in 3 pigtail monkeys support the hypothesis that laser imaging is safe and improves the accuracy of probe placement., Conclusions: Noninvasive laser speckle imaging can be performed safely in nonhuman primates. Because improved probe placement may reduce morbidity associated with percutaneous rhizotomies, efficacy trials of laser speckle imaging should be conducted in humans.

Objectives/hypothesis: To determine the feasibility of using a mouse tumor model as a microsurgical training tool for otolaryngology-head and neck surgery (OHNS) trainees., Study Design: Animal study., Methods: We injected athymic nude mice with human cutaneous squamous cell carcinoma (A431 cell line) deep to the parotid region overlying the masseter muscle. We sacrificed the animals 1 to 3 weeks postinjection, once a visible tumor growth was confirmed. We then asked 10 OHNS trainees to excise the tumor with preservation of the facial nerves under a high-magnification dissecting microscope. The trainees graded the tasks in several areas of specific measures using a visual analogue scale (VAS) including 1) tumor texture, 2) surgical realism, 3) usefulness, and 4) difficulty of the task., Results: Noticeable tumor growth occurred within 5 days following A431 cell injection and reached measureable size (0.5-1.5 cm) within 1 to 3 weeks. The tumor displaced the facial nerve laterally and medially, with few demonstrating infiltration of the nerve. VAS scores (± standard deviation) were 8.1 (± 1.7), 7.7 (± 2.5), 9.0 (± 0.9) and 6.6 (± 1.9) for tumor texture, surgical realism, usefulness, and the difficulty of the task, respectively., Conclusions: We demonstrate a novel, reliable and cost-effective mouse model for simulating tumor extirpation microsurgery with preservation of important neural structures. OHNS trainees have found this simulation model to be realistic, useful, and appropriately challenging., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: The aim of this study was to identify the facial areas defined by thermal gradient, in individuals compatible with the pattern of normality, and to quantify and describe them anatomically., Methods: The sample consisted of 161 volunteers, of both genders, aged between 26 and 84 years (63 ± 15 years)., Results: The results demonstrated that the thermal gradient areas suggested for the study were present in at least 95% of the thermograms evaluated and that there is significant difference in temperature between the genders, racial group and variables "odontalgia", "dental prothesis" and "history of migraine" (p < 0.05). Moreover, there was no statistically significant difference in the absolute temperatures between ages, and right and left sides of the face, in individuals compatible with the pattern of normality (ΔT = 0.11°C)., Conclusions: The authors concluded that according to the suggested areas of thermal gradients, these were present in at least 95% of all the thermograms evaluated, and the areas of high intensity found in the face were medial palpebral commissure, labial commissure, temporal, supratrochlear and external acoustic meatus, whereas the points of low intensity were inferior labial, lateral palpebral commissure and nasolabial.

We traced the connections of the macaque Granular Frontal Opercular (GrFO) area, located in the rostralmost part of the frontal opercular margin, and compared them with those of the caudally adjacent dorsal opercular (DO) and precentral opercular (PrCO) areas. Area GrFO displays strong connections with areas DO, PrCO, and ventrolateral prefrontal (VLPF) area 12l, and even more with the mostly hand-related ventral premotor (PMv) area F5a. Other connections involve the mostly face/mouth-related PMv area F5c, the arm-related area F6/pre-SMA, the hand-related fields of VLPF areas 46v and 12r, and area SII, mostly the hand representation. Furthermore, area GrFO shows rich connectivity with several components of the limbic system including orbitofrontal areas 12o, 12m, and 11, the agranular and dysgranular insula, the agranular cingulate area 24, and the amygdala. Thalamic afferents originate primarily from the parvocellular and the magnocellular subdivisions of the mediodorsal nucleus and from midline and intralaminar nuclei. This connectivity pattern clearly distinguishes area GrFO from areas DO and PrCO, characterized by a connectivity mostly involving oral sensorimotor and gustatory areas/subcortical structures. The present data suggest, based on connectivity patterns, an involvement of area GrFO in the cortical circuits for controlling goal-directed hand and face/mouth actions. In this context, area GrFO could represent a gateway for the access of limbic inputs, for example about subjective values, emotional significance of stimuli or internal states, to the PMv areas involved in selecting appropriate goal-directed hand and mouth/face actions.

Background and Objective: Symptoms and signs of sensorial disturbances are characteristic features of a migraine headache. Somatosensory temporal discrimination measures the temporal threshold to perceive two separate somaesthetic stimuli as clearly distinct. This study aimed to evaluate somaesthetic perception in migraine patients by measuring the somatosensory temporal discrimination thresholds., Methods: The study included 12 migraine patients without aura and 12 volunteers without headache. Somatosensory temporal discrimination threshold (STDT) values were measured in the face (V3) and hands (C7) during a lateralized headache attack and the headache-free interictal period. The disease duration, pain intensity, phonophobia, photophobia, nausea, vomiting, and brush allodynia were also recorded during the migraine attack., Results: STDT values were within normal limits and not different between the control group and the interictal period in migraine patients. Compared to the headache-free period, STDT values during the attack were significantly prolonged in the contralateral hand (C7) (155.7 ± 84.2 vs 40.6 ± 16.1 ms [P < .001]), ipsilateral hand (C7) (88.6 ± 51.3 vs 31.4 ± 14.2 ms [P < 0.001]), contralateral face (V3) (65.5 ± 35.4 vs 37.6 ± 22.2 ms [P = .006]) and ipsilateral face (V3) (104.1 ± 44.5 vs 37.5 ± 21.4 ms [P < 0.001]) according to the lateralization of the headache. Ictal STDT values of the contralateral hand and ipsilateral face were significantly increased compared to that of the ipsilateral hand and contralateral face (155.7 ± 84.2 ms vs 88.6 ± 5.1.3 ms [P = .001], 104.1 ± 44.5 ms vs 65.5 ± 35.4 ms [P = 0.001]). No allodynia was detected in the areas that were tested for somatosensory temporal discrimination. The visual analog scale scores were correlated with the somatosensory temporal discrimination thresholds of the contralateral hand (r = 0.602, P = .038), whereas no correlation was detected between the somatosensory temporal discrimination thresholds and disease duration, brush allodynia in the forehead, phonophobia, photophobia, nausea and vomiting., Conclusion: The study demonstrates for the first time that somatosensory temporal discrimination thresholds are elevated during migraine attacks. A transient disruption of the central processing of somaesthetic stimuli during the lateralized migraine attack may provide additional information to understand the mechanisms of the cognitive and sensory perception impairment associated with migraine headache and may have diagnostic value., (© 2015 American Headache Society.)

Most nerve communications reported in the literature were found between the terminal branches. This study aimed to clarify and classify patterns of proximal communications between the buccal branches (BN) of the facial nerve and the infraorbital nerve (ION).The superficial musculoaponeurotic system protects any communication sites from conventional dissections. Based on this limitation, the soft tissues of each face were peeled off the facial skull and the facial turn-down flap specimens were dissected from the periosteal view. Dissection was performed in 40 hemifaces to classify the communications in the sublevator space. Communication site was measured from the ala of nose.A double communication was the most common type found in 62.5% of hemifaces. Triple and single communications existed in 25% and 10% of 40 hemiface specimens, respectively. One hemiface had no communication. The most common type of communication occurred between the lower trunk of the BN of the facial nerve and the lateral labial (fourth) branch of the ION (70% in 40 hemifaces). Communication site was deep to the levator labii superioris muscle at 16.2 mm from the nasal ala. Communications between the motor and the sensory nerves in the midface may be important to increase nerve endurance and to compensate functional loss from injury.Proximal communications between the main trunks of the facial nerve and the ION in the midface exist in every face. This implies some specific functions in normal individuals. Awareness of these nerves is essential in surgical procedure in the midface.

Background: Gracilis muscle and its motor nerve belongs to most commonly used flap for facial reanimation. However, it is performed in two steps, which is time consuming. One stage technique can be also performed, but the length of the motor nerve cannot be currently determined before surgery., Aim: The present study was conducted in order to evaluate the body composition on the length and suitability of the motor nerve of gracilis muscle for one stage facial reanimation., Methods: The gracilis flaps along with the motoric nerve were dissected from 20 fresh cadavers (6 females, 14 males). The length of the lower extremity from superior iliac anterior spine to the bottom of the heel and BMI were measured. Regression analysis of lower extremity length and BMI to the actual length of the motor nerve of gracilis flap was performed., Results: The linear regression analysis showed a positive correlation between the length of the lower limb and the size of the motor nerve length (r = 0.5060, p < 0.05), as well as between the BMI and the size of the motor nerve length (r = 0.5073, p < 0.05). Also, the males had longer motor nerve when compared to females by 13 % (p < 0.05). No difference between females and males in BMI was observed., Conclusion: The length from the superior iliac anterior spine, BMI and gender seemed to be potential factors that could help to predict the length of the gracilis flap motor nerve for the one stage facial reanimation. However, further studies evaluating other anatomical factors and validating the possible prediction rule for one stage reanimation success are needed (Fig. 3, Ref. 14).

Background: Various sensory impairments have been reported in patients with lateral medullary syndrome, also known as Wallenberg syndrome. The typical sensory impairments experienced by patients with this condition are ipsilateral facial and contralateral trunk and limb thermal hypesthesia and hypoalgesia. Tactile (light touch) sensation is not generally diminished. Here we report the case of a 35-year-old man with lateral medullary infarction who had atypical sensory impairment., Methods: We examined the results from the neurological examination of the patient as well as findings from computed tomography of the head and magnetic resonance imaging., Results: Magnetic resonance imaging showed left lateral medullary infarction caused by left posterior inferior cerebellar artery dissection. Neurological examination revealed both tactile and thermal/pain hypesthesia on the left side of the patient's face, and thermal/pain hypesthesia on his right upper and lower limbs., Conclusion: There are two types of tactile sensation: epicritic and protopathic. Facial tactile sensation is usually thought to be associated with epicritic tactile sensation, which travels through principal sensory nuclei of the trigeminal nerve. The protopathic pathway travels down through the spinal tract via the trigeminal nerve and is not considered a primary pathway. However, in this case the protopathic tactile sensation pathway might be involved, and it caused facial tactile hypesthesia. Because most of previous case reports and literature reviews focused only on thermal/pain hypesthesia, we believe that this case provides critical information on the brainstem neuroanatomy, especially for the protopathic tactile sensation pathway in patients with stroke., (Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: The corticobulbar tract of the face and tongue, a critical white matter tract connecting the primary motor cortex and the pons, is rarely detected by deterministic DTI fiber tractography. Detection becomes even more difficult in the presence of a tumor. The purpose of this study was to compare identification of the corticobulbar tract by using deterministic and probabilistic tractography in patients with brain tumor., Materials and Methods: Fifty patients with brain tumor who underwent DTI were studied. Deterministic tractography was performed by using the fiber assignment by continuous tractography algorithm. Probabilistic tractography was performed by using a Monte Carlo simulation method. ROIs were drawn of the face and tongue motor homunculi and the pons in both hemispheres., Results: In all subjects, fiber assignment by continuous tractography was ineffectual in visualizing the entire course of the corticobulbar tract between the face and tongue motor cortices and the pons on either side. However, probabilistic tractography successfully visualized the corticobulbar tract from the face and tongue motor cortices in all patients on both sides. No significant difference (P < .08) was found between both sides in terms of the number of voxels or degree of connectivity. The fractional anisotropy of both the face and tongue was significantly lower on the tumor side (P < .03). When stratified by tumor type, primary-versus-metastatic tumors, no differences were observed between tracts in terms of the fractional anisotropy and connectivity values (P > .5)., Conclusions: Probabilistic tractography successfully reconstructs the face- and tongue-associated corticobulbar tracts from the lateral primary motor cortex to the pons in both hemispheres., (© 2015 by American Journal of Neuroradiology.)

Patients suffering from persistent orofacial pain may sporadically report that the painful area feels "swollen" or "differently," a phenomenon that may be conceptualized as a perceptual distortion because there are no clinical signs of swelling present. Our aim was to investigate whether standardized experimental pain and sensory deprivation of specific orofacial test sites would lead to changes in the size perception of these face areas. Twenty-four healthy participants received either 0.2 mL hypertonic saline (HS) or local anesthetics (LA) into six regions (buccal, mental, lingual, masseter muscle, infraorbital and auriculotemporal nerve regions). Participants estimated the perceived size changes in percentage (0 % = no change, -100 % = half the size or +100 % = double the size), and somatosensory function was checked with tactile stimuli. The pain intensity was rated on a 0-10 Verbal Numerical Rating Scale (VNRS), and sets of psychological questionnaires were completed. HS and LA were associated with significant self-reported perceptual distortions as indicated by consistent increases in perceived size of the adjacent face areas (P ≤ 0.050). Perceptual distortion was most pronounced in the buccal region, and the smallest increase was observed in the auriculotemporal region. HS was associated with moderate levels of pain VNRS = 7.3 ± 0.6. Weak correlations were found between HS-evoked perceptual distortion and level of dissociation in two regions (P < 0.050). Experimental pain and transient sensory deprivation evoked perceptual distortions in all face regions and overall demonstrated the importance of afferent inputs for the perception of the face. We propose that perceptual distortion may be an important phenomenon to consider in persistent orofacial pain conditions.

Eyeblinks are defined as a rapid closing and opening of the eyelid. Three types of blinks are defined: spontaneous, reflexive, and voluntary. Here, we focus on the cortical correlates of spontaneous blinks, using functional magnetic resonance imaging (fMRI) in the nonhuman primate. Our observations reveal an ensemble of cortical regions processing the somatosensory, proprioceptive, peripheral visual, and possibly nociceptive consequences of blinks. These observations indicate that spontaneous blinks have consequences on the brain beyond the visual cortex, possibly contaminating fMRI protocols that generate in the participants heterogeneous blink behaviors. This is especially the case when these protocols induce (nonunusual) eye fatigue and corneal dryness due to demanding fixation requirements, as is the case here. Importantly, no blink related activations were observed in the prefrontal and parietal blinks motor command areas nor in the prefrontal, parietal, and medial temporal blink suppression areas. This indicates that the absence of activation in these areas is not a signature of the absence of blink contamination in the data. While these observations increase our understanding of the neural bases of spontaneous blinks, they also strongly call for new criteria to identify whether fMRI recordings are contaminated by a heterogeneous blink behavior or not., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Unlabelled: Although treating facial palsy is considered debilitating for patients, trigeminal nerve palsy and sensory deficits of the face are overlooked components of disability. Complete anesthesia leaves patients susceptible to occult injury, and facial sensation is an important component of interaction and activities of daily living. Sensory reconstruction is well established in the restoration of hand sensation; however, only one previous report proposed a surgical strategy for sensory nerve reconstruction of the face with use of nerve transfers. Nerve transfers, when used alone, have limited application because of their restricted arc of rotation in the face; extending their arc by adding nerve grafts greatly expands their utility. The following cases demonstrate the early results after V2 and V3 reconstruction with cross-face nerve grafts in three patients with acquired trigeminal nerve palsy. Cross-face nerve grafts using the sural nerve permit more proximal reconstruction of the infraorbital and mental nerves, which allows reinnervation of their entire cutaneous distribution. All patients demonstrated improved sensation in the reconstructed dermatomes, and no patients reported donor-site abnormalities. Cross-face nerve grafts result in minimal donor-site morbidity and are promising as a surgical strategy to address sensory deficits of the face., Clinical Question/level of Evidence: Therapeutic, V.

Unlabelled: Habituation and sensitization are important features of individual sensitivity to repetitive noxious stimulation and have been investigated in numerous studies. However, it is unclear whether these phenomena vary depending on the site of stimulation. Here we compared short-term and long-term effects of painful heat stimulation on the forehead and limb using an established longitudinal heat pain paradigm performed over 8 consecutive days in 36 healthy volunteers. Participants were randomized into 2 groups; participants received repetitive heat pain stimulation either on the left volar forearm or on the left side of the forehead. Our data show a comparable degree of habituation over the course of 8 days in both groups. However, participants in the trigeminal stimulation group exhibited stronger within-session sensitization (indexed by a higher within-session increase in pain intensity ratings) than those who received the forearm stimulation. Furthermore, over the course of the experiment we found a correlation between habituation and anxiety, showing less habituation in participants with higher trait anxiety scores. Our findings are in line with somatotopic differences in response to painful stimulation and a higher proneness of trigeminal pain to sensitization processes, which might be explained by the biological relevance of the head and facial area for vital functions. The contribution of this sensitivity to the development and maintenance of clinical facial pain and headache disorders warrants further investigation., Perspective: This study uses psychophysical methods to evaluate the differences in long-term habituation and short-term sensitization to heat pain between the trigeminal and spinal systems. We found stronger sensitization for trigeminal compared with nociceptive stimuli on the forearm. The contribution of this sensitivity to clinical pain states warrants further investigation., (Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.)

Rodents use their vibrissae to detect and discriminate tactile features during active exploration. The site of mechanical transduction in the vibrissa sensorimotor system is the follicle sinus complex and its associated vibrissa. We study the mechanics within the ring sinus (RS) of the follicle in an ex vivo preparation of the mouse mystacial pad. The sinus region has a relatively dense representation of Merkel mechanoreceptors and longitudinal lanceolate endings. Two-photon laser-scanning microscopy was used to visualize labeled cell nuclei in an ∼ 100-nl vol before and after passive deflection of a vibrissa, which results in localized displacements of the mechanoreceptor cells, primarily in the radial and polar directions about the vibrissa. These displacements are used to compute the strain field across the follicle in response to the deflection. We observe compression in the lower region of the RS, whereas dilation, with lower magnitude, occurs in the upper region, with volumetric strain ΔV/V ∼ 0.01 for a 10° deflection. The extrapolated strain for a 0.1° deflection, the minimum angle that is reported to initiate a spike by primary neurons, corresponds to the minimum strain that activates Piezo2 mechanoreceptor channels., (Copyright © 2015 the American Physiological Society.)

Background: The surgical anatomy of the midface relevant to its subperiosteal elevation and repositioning is assessed., Objectives: The aim of this study is to give more details on the anatomy relevant to the midface lift., Methods: Twenty hemifacial dissections were performed. The location of the zygomatic branches of the facial nerve (ZBFN) and the terminal branches of the infraorbital nerve (ION) were dissected. The location of the masseteric and zygomatic ligaments and the elevation of midface following their release were documented., Results: On average, there were 3 branches of the facial nerve innervating the zygomatic major muscle and 1.8 branches entering the muscle superior to the caudal origin of the zygomaticomaxillary (ZM) suture. The most superior ZBFN was found to lie at an average of 6.2 ± 1.6 mm cranial to ZM suture and 1.4 ± 0.4 mm superficial to the bone. The most inferior branch was at a mean of 4.8 ± 3.3 mm inferior to ZM suture. On average the ION had 5.2 branches that traveled for 10.2 mm above the periosteum before they passed into a superficial plane. Division of the zygomatico-masseteric retaining ligaments allowed for elevation of the midface by 4.8 ± 1.0 mm medially and 5.5 ± .9 mm laterally., Conclusions: Branches of the ZBFN and ION lie in close proximity to the subperiosteal plane in the midface. These branches are at risk for damage during release of the upper zygomatic ligaments and placement of the periosteal suspension sutures during midface elevation procedures., (© 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.)

Unlabelled: Chronic pruritic conditions are often associated with dry skin and loss of epidermal barrier integrity. In this study, repeated application of acetone and ether followed by water (AEW) to the cheek skin of mice produced persistent scratching behavior with no increase in pain-related forelimb wiping, indicating the generation of itch without pain. Cheek skin immunohistochemistry showed a 64.5% increase in total epidermal innervation in AEW-treated mice compared to water-treated controls. This increase was independent of scratching, because mice prevented from scratching by Elizabethan collars showed similar hyperinnervation. To determine the effects of dry skin treatment on specific subsets of peripheral fibers, we examined Ret-positive, calcitonin gene-related peptide (CGRP)-positive, and glial cell line-derived neurotrophic factor family receptor α3 (GFRα3)-positive intraepidermal fiber density. AEW treatment increased Ret-positive fibers but not CGRP-positive or GFRα3-positive fibers, suggesting that a specific subset of nonpeptidergic fibers could contribute to dry skin itch. To test whether trigeminal ganglion neurons innervating the cheek exhibited altered excitability after AEW treatment, primary cultures of retrogradely labeled neurons were examined using whole-cell patch clamp electrophysiology. AEW treatment produced no differences in measures of excitability compared to water-treated controls. In contrast, a significantly higher proportion of trigeminal ganglion neurons was responsive to the nonhistaminergic pruritogen chloroquine after AEW treatment. We conclude that nonpeptidergic, Ret-positive fibers and chloroquine-sensitive neurons may contribute to dry skin pruritus., Perspective: This study examines the underlying neurobiological mechanisms of persistent dry skin itch. Our results indicate that nonpeptidergic epidermal hyperinnervation and nonhistaminergic pruritic receptors are potential targets for chronic pruritus., (Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.)

Cerebellar Purkinje cells (PCs) respond to sensory stimulation via climbing fiber and mossy fiber-granule cell pathways, and generate motor-related outputs according to internal rules of integration and computation. However, the dynamic properties of sensory information processed by PC in mouse cerebellar cortex are currently unclear. In the present study, we examined the effects of the gamma-aminobutyric acid receptor A (GABA(A)) antagonist, gabazine, on the stimulation train on the simple spike firing of PCs by electrophysiological recordings method. Our data showed that the output of cerebellar PCs could be significantly affected by all pulses of the low-frequency (0.25 -2 Hz) sensory stimulation train, but only by the 1st and 2nd pulses of the high-frequency (≥ 4 Hz) sensory stimulation train. In the presence of gabazine (20 μM), each pulse of 1 Hz facial stimulation evoked simple spike firing in the PCs, but only the 1st and 2nd pulses of 4 Hz stimulation induced an increase in simple spike firing of the PCs. These results indicated that GABAA receptor-mediated inhibition did not significantly affect the frequency properties of sensory stimulation evoked responses in the mouse cerebellar PCs.

Complexity of facial anatomy and its rich innervation complicate the diagnosis of prosopalgias. An acute syndrome, including trigeminal, myofascial and cervical pains, is described. Authors discuss algesic interrelations, combined therapeuric effect and peculiarities of diagnosis.

Sensory perception decreases with age, and is altered as a function of sex. Very little is known about the age- and sex-related changes in vibrotactile detection thresholds (VDTs) of the face relative to the glabrous hand. This study utilized a single-interval up/down (SIUD) adaptive procedure to estimate the VDT for mechanical stimuli presented at 5, 10, 50, 150, 250, and 300 Hz at two sites on the face, including the right non-glabrous surface of the oral angle and the right lower lip vermilion; and on the hand on the glabrous surface of the distal phalanx of the right dominant index finger. Eighteen right-handed healthy younger adults and 18 right-handed healthy older adults participated in this study. VDTs were significantly different between the three stimulus sites (p < 0.0001), and dependent on stimulus frequency (p < 0.0001) and the sex of the participants (p < 0.005). VDTs were significantly higher for older adults when compared to younger adults for the finger stimulation condition (p < 0.05). There were significant differences (p < 0.05) in cheek and lower lip VDTs between male and female subjects. Difference in the VDTs between the three stimulation sites is presumed to reflect the unique typing and distribution of mechanoreceptors in the face and hand. Age-related differences in finger skin sensitivity are likely due to changes in the physical structure of skin, changes in the number and morphology of the mechanoreceptors, differences in the functional use of the hand, and its central representation. Sex-related differences in the VDTs may be due to the differences in tissue conformation and thickness, mechanoreceptor densities, skin hydration, or temperature characteristics.

Purpose: The current study's purpose was to determine morphometric analysis of all facial foramina and mandibular angle relative to surgical landmarks from cone beam computed tomographic scans., Materials and Methods: Three-dimensional computed tomographic scans were reconstructed from data of 100 patients (200 sides) aged between 19 and 76 years. Morphometric measurements of all facial foramina relative to surgical landmarks were taken. Mandibular angle was measured., Results: There was no statistically significant difference between the left and right sides for all parameters (P > 0.05). Therefore, we found bilateral symmetry in the position of all facial foramina and mandibular angle. However, statistically significant differences were determined in sexes in some of these parameters and mandibular angle., Conclusions: The knowledge about locations of facial foramina and mandibular angle is important for performing local nerve block and surgery in the face to avoid the neurovascular structures. This study provides a guideline for locations of facial foramina and mandibular angle, which may help surgeons to understand the nerve location precisely during surgery.

Object: Neurosurgeons are frequently the primary physicians measuring pain relief in patients with trigeminal neuralgia (TN). Unfortunately, the measurement of pain can be complex. The Brief Pain Inventory-Facial (BPI-Facial) is a reliable and validated multidimensional tool that consists of 18 questions. It measures 3 domains of pain: 1) pain intensity (worst and average pain intensity), 2) interference with general activities of daily living (ADL), and 3) face-specific pain interference. The objective of this paper is to determine the patient-reported minimum clinically important difference (MCID) using the BPI-Facial., Methods: The authors conducted a retrospective study of 234 patients with TN seen in a single neurosurgeon's office. Patients completed baseline and 1-month follow-up BPI-Facial questionnaires. The MCID was calculated using an anchor-based approach in which the defined anchor was the 7-point patient global impression of change (PGIC). Two statistical methods were employed: mean change score and optimal cutoff point., Results: Using the mean change score method, the investigators calculated the MCID for the 3 domains of the BPIFacial: 44% and 30% improvement in pain intensity at its worst and average, respectively, 54% improvement in interference with general ADL, and 63% improvement in interference with facial ADL. Using the optimal cutoff point method, they also calculated the MCID for the 3 domains of the BPI-Facial: 57% and 28% improvement in pain intensity at its worst and average, respectively, 75% improvement in interference with general ADL, and 62% improvement in interference with facial ADL., Conclusions: The BPI-Facial is a multidimensional pain scale that measures 3 domains of pain. Although 2 statistical methods were used to calculate the MCID, the optimal cutoff point method was the superior one because it used data from the majority of subjects included in this study. A 57% improvement in pain intensity at its worst and a 28% improvement in pain intensity at its average were the MCIDs for patients with facial pain. A greater improvement was needed to achieve the MCID for interference with general and facial ADL. A 75% improvement in interference with general ADL and a 62% improvement in interference with facial ADL were needed to achieve an MCID. While pain intensity is easier to measure, pain's interference with ADL may be more important for patient outcomes when designing or evaluating interventions in the field of TN. The BPI-Facial is a useful instrument to measure changes in multidimensional aspects of pain in patients with TN.

Mammalian tactile hairs are commonly found on specific, restricted regions of the body, but Florida manatees represent a unique exception, exhibiting follicle-sinus complexes (FSCs, also known as vibrissae or tactile hairs) on their entire body. The orders Sirenia (including manatees and dugongs) and Hyracoidea (hyraxes) are thought to have diverged approximately 60 million years ago, yet hyraxes are among the closest relatives to sirenians. We investigated the possibility that hyraxes, like manatees, are tactile specialists with vibrissae that cover the entire postfacial body. Previous studies suggested that rock hyraxes possess postfacial vibrissae in addition to pelage hair, but this observation was not verified through histological examination. Using a detailed immunohistochemical analysis, we characterized the gross morphology, innervation and mechanoreceptors present in FSCs sampled from facial and postfacial vibrissae body regions to determine that the long postfacial hairs on the hyrax body are in fact true vibrissae. The types and relative densities of mechanoreceptors associated with each FSC also appeared to be relatively consistent between facial and postfacial FSCs. The presence of vibrissae covering the hyrax body presumably facilitates navigation in the dark caves and rocky crevices of the hyrax's environment where visual cues are limited, and may alert the animal to predatory or conspecific threats approaching the body. Furthermore, the presence of vibrissae on the postfacial body in both manatees and hyraxes indicates that this distribution may represent the ancestral condition for the supraorder Paenungulata., (© 2015 S. Karger AG, Basel.)

The angle of the jaw is innervated by the auricular branch of the superficial cervical plexus (SCP). Cervical cutaneous nerves of the CP carry the sensation from the antero-lateral cervical skin. It is clinically relevant to identify the cervical cutaneous nerve distribution and the nerve point using superficial landmarks but published studies describing the emerging patterns and cervical cutaneous nerve branch distributions in the mandible are rare. The overlap between the cervical and trigeminal and facial nerve distributions and anastomoses is highly variable. The objective of this study was to characterize the distribution of the SCP nerves in the different parts of the mandible. Two hundred and fifty fresh and formalin-fixed human cadaver heads were microdissected to observe the distribution of the transverse cervical (TCN) and great auricular (GAN) nerves. Two main groups (G1 and G2) based on the emergence of the TCN and GAN behind the posterior edge of the sternocleidomastoid muscle and three types (T1, T2, and T3) based on their distribution in the different mandibular parts were observed. Statistical analysis showed that parameters related to the mandibular side (P = 0.307), gender (P = 0.218), and group (P = 0.111) did not influence the facial distribution of these nerves. The only parameter influencing the distribution was the type of nerve (GAN and TCN) (P < 0.001). In the face, the SCP reached the mandible in 97% of cases, its distribution and extent were subject-dependent. These results confirmed that the SCP could supply accessory innervation to the mandible through the TCN., (© 2014 Wiley Periodicals, Inc.)

Since the first facial transplantation in 2005, 28 have been done worldwide with encouraging immunological, functional, psychological, and aesthetic outcomes. Unlike solid organ transplantation, which is potentially life-saving, facial transplantation is life-changing. This difference has generated ethical concerns about the exposure of otherwise young and healthy individuals to the sequelae of lifelong, high-dose, multidrug immunosuppression. Nevertheless, advances in immunomodulatory and immunosuppressive protocols, microsurgical techniques, and computer-aided surgical planning have enabled broader clinical application of this procedure to patients. Although episodes of acute skin rejection continue to pose a serious threat to face transplant recipients, all cases have been controlled with conventional immunosuppressive regimens, and no cases of chronic rejection have been reported., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this study was to investigate whether watching one's own face being touched in a reversal mirror condition modulates orofacial somatosensory sensitivity. A total of 37 healthy volunteers participated in a pilot study, the main study, and a control experiment. In the main experiment, 16 participants received seven different intensities of pinprick stimuli in the right infraorbital region. The perceived stimulus intensity was rated on a 0-50-100 numerical rating scale (NRS). In addition, the pinprick threshold (PiPT) was evaluated in the same region using an electronic von Frey device. During stimuli, participants were watching their own face in two different conditions (normal and reversal mirror) in randomized order. Subjective experiences during each condition were assessed with a questionnaire containing nine statements. The participants rated their level of agreement with the statements using a 7-item Likert scale. There were significant main effects on NRS scores of stimulus forces (p < 0.001) and experimental condition (p < 0.001). Post hoc analyses showed that stimulation with higher force levels induced significantly higher NRS scores (p < 0.001), but interestingly, there were significantly lower NRS scores in the reversal mirror condition than in the normal mirror condition (p < 0.001). There was no significant main effect of experimental condition on PiPT (p = 0.184). The experimental condition influenced the response to several statements significantly (p < 0.001). The somatosensory sensitivity may be impaired when the location of stimulation is not in accordance with the perception. In conclusion, hypoesthetic effects of a reversal mirror were present for fixed force measures but not for threshold measures. Further studies are now needed to describe the potential implications for other somatosensory modalities and orofacial pain conditions.

The aim of this study was to examine the tactile sensory and pain thresholds in the face, tongue, hand and finger of subjects asymptomatic for pain. Sixteen healthy volunteers (eight men and eight women, mean age 35·7 years, range 27-41) participated. Using Semmes-Weinstein monofilaments, the tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) were measured at five sites: on the cheek skin (CS), tongue tip (TT), palm side of the thenar skin (TS), dorsum of the hand (DH) and the finger tip (FT). The difference between the tactile sensory and pain threshold (FPT-TDT) was also calculated. Both for the TDT and FPT, TT and DH had the lowest and highest values, respectively. As for the FPT-TDT, there were no significant differences among the measurement sites. As the difference between FPT and TDT (FPT-TDT) is known to be an important consideration in interpreting QST (quantitative sensory testing) data and can be altered by neuropathology, taking the FPT-TDT as a new parameter in addition to the TDT and FPT separately would be useful for case-control studies on oro-facial pain patients with trigeminal neuralgia, atypical facial pain/atypical odontalgia and burning mouth syndrome/glossodynia., (© 2014 John Wiley & Sons Ltd.)

Microelectrocorticography (µECoG) provides insights into the cortical organization with high temporal and spatial resolution desirable for better understanding of neural information processing. Here we evaluated the use of µECoG for detailed cortical recording of somatosensory evoked potentials (SEPs) in an ovine model. The approach to the cortex was planned using an MRI-based 3D model of the sheep's brain. We describe a minimally extended surgical procedure allowing placement of two different µECoG grids on the somatosensory cortex. With this small craniotomy, the frontal sinus was kept intact, thus keeping the surgical site sterile and making this approach suitable for chronic implantations. We evaluated the procedure for chronic implantation of an encapsulated µECoG recording system. During acute and chronic recordings, significant SEP responses in the triangle between the ansate, diagonal, and coronal sulcus were identified in all animals. Stimulation of the nose, upper lip, lower lip, and chin caused a somatotopic lateral-to-medial, ipsilateral response pattern. With repetitive recordings of SEPs, this somatotopic pattern was reliably recorded for up to 16 weeks. The findings of this study confirm the previously postulated ipsilateral, somatotopic organization of the sheep's sensory cortex. High gamma band activity was spatially most specific in the comparison of different frequency components of the somatosensory evoked response. This study provides a basis for further acute and chronic investigations of the sheep's sensory cortex by characterizing its exact position, its functional properties, and the surgical approach with respect to macroanatomical landmarks., (© 2014 Wiley Periodicals, Inc.)

Magnetoencephalography and independent component analysis (ICA) was utilized to study and characterize neural adaptation in the somatosensory cortical network. Repetitive punctate tactile stimuli were applied unilaterally to the dominant hand and face using a custom-built pneumatic stimulator called the TAC-Cell. ICA-based source estimation from the evoked neuromagnetic responses indicated cortical activity in the contralateral primary somatosensory cortex (SI) for face stimulation, while hand stimulation resulted in robust contralateral SI and posterior parietal cortex (PPC) activation. Activity was also observed in the secondary somatosensory cortical area (SII) with reduced amplitude and higher variability across subjects. There was a significant difference in adaptation rate between SI and higher-order somatosensory cortices for hand stimulation. Adaptation was significantly dependent on stimulus frequency and pulse index within the stimulus train for both hand and face stimulation. The peak latency of the activity was significantly dependent on stimulation site (hand vs. face) and cortical area (SI vs. PPC). The difference in the peak latency of activity in SI and PPC is presumed to reflect a hierarchical serial-processing mechanism in the somatosensory cortex.

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.

Purpose: In diabetic patients, single-fiber electromyography (SFEMG) is often abnormal in the limb muscles and is considered unreliable in diagnosis of synaptic disorders. We aimed to compare SFEMG abnormalities of frontalis muscle (FM) and extensor digitorum communis muscle in diabetic patients with neuropathy and without neuropathy., Methods: Stimulation SFEMG of FM and extensor digitorum communis muscle was performed in matched groups of 30 diabetic patients with neuropathy and 20 diabetic patients without neuropathy., Results: Single-fiber electromyography in the FM was abnormal in four diabetic patients with neuropathy and in one diabetic patient without neuropathy. Changes were rather mild. Extensor digitorum communis abnormalities were significantly more frequent-in 20 diabetic patients with neuropathy and in 7 diabetic patients without neuropathy (P < 0.001). We never observed a patient with abnormal FM but normal extensor digitorum communis muscle., Conclusions: In diabetes, FM exhibits rare and quite mild SFEMG changes. This muscle may be suitable for SFEMG in diabetic patients with clinical suspicion for synaptic disorder.

The aim of this two-part series is to provide an up-to-date review of essential regional nerve blocks for dermatological practice. In Part 1, we give a concise overview of local anaesthetics and their potential complications, as well as the relevant anatomy and cutaneous innervation of the face and scalp. This culminates in a step-by-step practical guide to performing each nerve block., (© 2014 British Association of Dermatologists.)

Facial branchiomotor neurons (FBMs) of vertebrates typically develop in rhombomere 4 (r4), and in mammals and several other vertebrate taxa, migrate caudally into r6 and subsequently laterally and ventrally to the pial surface. How similar or dissimilar these migratory processes between species are at a molecular level remains unclear. In zebrafish and mouse, mutations in certain PCP genes disrupt normal caudal migration of FBMs. Zebrafish prickle1a (prickle-like 1a) and prickle1b, two orthologs of Prickle1, act non-cell-autonomously and cell-autonomously, respectively, to regulate FBM migration. Here, we show that, in Prickle1 (C251X/C251X) mice which have reduced Prickle1 expression, the caudal migration of FBMs is affected. Most FBM neurons do not migrate caudally along the floor plate. However, some neurons perform limited caudal migration such that the neurons eventually lie near the pial surface from r4 to anterior r6. FBMs in Prickle1 (C251X/C251X) mice survive until P0 and form an ectopic nucleus dorsal to the olivo-cochlear efferents of r4. Ror2, which modifies the PCP pathway in other systems, is expressed by the migrating mouse FBMs, but is not required for FBM caudal migration. Our results suggest that, in mice, Prickle1 is part of a molecular mechanism that regulates FBM caudal migration and separates the FBM and the olivo-cochlear efferents. This defective caudal migration of FBMs in Prickle1C251X mutants resembles Vangl2 mutant defects. In contrast to other developing systems that show similar defects in Prickle1, Wnt5a and Ror2, the latter two only have limited or no effect on FBM caudal migration.

Mammals perform a multitude of well-coordinated orofacial behaviors such as breathing, sniffing, chewing, licking, swallowing, vocalizing, and in rodents, whisking. The coordination of these actions must occur without fault to prevent fatal blockages of the airway. Deciphering the neuronal circuitry that controls even a single action requires understanding the integration of sensory feedback and executive commands. A far greater challenge is to understand the coordination of multiple actions. Here, we focus on brainstem circuits that drive rhythmic orofacial actions. We discuss three neural computational mechanisms that may enable circuits for different actions to operate without interfering with each other. We conclude with proposed experimental programs for delineating the neural control principles that have evolved to coordinate orofacial behaviors., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this review was to familiarize the reader with critical facial nerve anatomy relating to facial rejuvenation surgeries. The temporal branch to the upper orbicularis oculi muscle (OOM): The temporal branch was under the temporoparietal fascia above the zygomatic arch and divided into 2 to 4 branches. The highest level of the twigs that entered the OOM on the x axis and the y axis with the origin of the lateral canthus is +2.51 ± 0.23 cm and +2.70 ± 0.35 cm; and the lowest, 0 cm and +2.68 ± 0.32 cm, respectively. The zygomatic and the buccal branch to the lower OOM: All pretarsal and preseptal OOMs were innervated by 5 to 7 terminal twigs of the zygomatic branches of the facial nerve that approached the muscle at a right angle. The medial portion of the lower OOM was innervated by 1 to 2 terminal twigs of the buccal branch, and the middle portion was innervated with 2 to 3 twigs of the zygomatic branch. The lateral portion was supplied by the uppermost zygomatic branch, which split into 2 to 4 twigs. The temporal branch to the corrugator supercilii muscle: A plexus mainly from the inferior ramus partly from the middle ramus of the temporal branch of the facial nerve enters the corrugator supercilii muscle in the supraorbital area. The temporal branch has as many as 4 to 7 rami, with interconnection among them. The buccal branch to the procerus muscle: The buccal branch crosses the intercanthal line (the nasion to the medial canthus) at approximately one third laterally. The nerve entrance was within a circle with a diameter of 5 mm, and its center was located 9 mm lateral and 10 mm superior from the nasion. It was approximately at the midpoint of the lateral half of the intercanthal line and the lower one third between the intercanthal line and the tangential line of the supraorbital rim. The buccal branch, the buccal fat pad, and the parotid duct: The buccal branches and the parotid duct crossed each other within a semicircle with a 30-mm radius. The base (diameter) was parallel to a horizontal line passing the corner of the mouth and 12 mm above. Its center was located 53 mm lateral to it. The buccal branches of the facial nerve have 2 locations at the buccal fat pad: type I, branches crossing superficial to the buccal fat pad in 14 (73.7%) of 19 specimens, and type II, 2 twigs passing through the buccal extension of the buccal fat pad in 5 (26.3%) of 19 specimens. The buccal branch to the upper orbicularis oris muscle: Approximately 4 branches (4.06 ± 0.83) entering the pars marginalis were found. Most ramifying points (14/17, 82%) were located within a circle with a 5-mm radius, and the center was 12 mm lateral and 26 mm superior to the mouth corner. The mandibular branch according to the neck position: At the one-fourth point, the border-nerve distance decreased (4.32 ± 2.60 mm) with the neck in ipsilateral rotation and the border-nerve distance increased (5.97 ± 2.62 mm) with the neck in contralateral rotation. We hope that this knowledge will aid surgeons in achieving successful outcomes.

Background: Facial paralysis of the lower face presents severe functional and aesthetic disturbance to patients. The gamut of facial paralysis correction is diverse and must be tailored to the patient. When nerve repair or free functional muscle transfer is unavailable, regional muscle transfer has become a staple in surgical management of facial paralysis. Previous masseter transfers relied on orbicularis oris attachment, which may be atrophic, adhered, or lengthened. Using fascia lata grafts, we describe the senior author's method of staged, split masseter transfer as a reliable method for reanimating the lower third of the face in appropriate candidates., Methods: The staged, split masseter muscle transfer is a 3-part repair. The first stage places a hemioral fascia lata graft to act as an anchor reinforcement. The second stage transfers the split masseter muscle, suturing to the fascia lata reinforced oral commissure. The third stage, a reefing procedure, is performed 6 to 10 months later under local anesthesia to reinforce attachments., Results: Six patients underwent the staged, split masseter muscle transfer. Mean age was 43 (15-67) years. Mean time to surgery from onset of deficit was 174 months (3 months to 65 years). All patients had significant improvement over preoperative symptoms. Symmetry was restored in repose. On movement, commissure excursion went from 0 to 6.67 mm in the superolateral vector. Of the 6 patients, 5 required an average of 1.5 outpatient revisions to achieve satisfactory results on average of 4.67 (4-127) months after the final stage., Conclusions: The staged, split masseter transfer is useful for restoring subtle reanimation in patients presenting with facial paralysis. The staged, split masseter transfer provides bulk and restores both static and dynamic function. We present a case series demonstrating excellent long-term functional results.

The head is innervated by 12 cranial nerves (I-XII) that regulate its sensory and motor functions. Cranial nerves are composed of sensory, motor, or mixed neuronal populations. Sensory neurons perceive generally somatic sensations such as pressure, pain, and temperature. These neurons are also involved in smell, vision, taste, and hearing. Motor neurons ensure the motility of all muscles and glands. Innervation plays an essential role in the development of the various orofacial structures during embryogenesis. Hypoplastic cranial nerves often lead to abnormal development of their target organs and tissues. For example, Möbius syndrome is a congenital disease characterized by defective innervation (i.e., abducens (VI) and facial (VII) nerves), deafness, tooth anomalies, and cleft palate. Hence, it is obvious that the peripheral nervous system is needed for both development and function of orofacial structures. Nerves have a limited capacity to regenerate. However, neural stem cells, which could be used as sources for neural tissue maintenance and repair, have been found in adult neuronal tissues. Similarly, various adult stem cell populations have been isolated from almost all organs of the human body. Stem cells are tightly regulated by their microenvironment, the stem cell niche. Deregulation of adult stem cell behavior results in the development of pathologies such as tumor formation or early tissue senescence. It is thus essential to understand the factors that regulate the functions and maintenance of stem cells. Yet, the potential importance of innervation in the regulation of stem cells and/or their niches in most organs and tissues is largely unexplored. This review focuses on the potential role of innervation in the development and homeostasis of orofacial structures and discusses its possible association with stem cell populations during tissue repair.

Multiple studies have demonstrated alterations in excitability in the central nervous system after peripheral nerve injury. However, there are few reports on changes in the central nervous system after peripheral facial nerve injury. Our objective was to determine the excitability changes that occur in the facial nucleus after facial nerve impairment. The excitability changes in the facial nucleus were investigated by assessing two types of compound muscle action potentials (M and F waves) in the orbicularis oculi muscles, evoked by electrical stimulation of the zygomatic branch of the facial nerve. In rats, M and F waves were measured in the orbicularis oculi muscles before and every week up to 8 weeks after the application of nerve compression under anesthesia. M and F waves disappeared after nerve compression, only to reappear 2 weeks later, although M-wave amplitude was decreased and the latencies of both waves were delayed. Thereafter, these waves recovered gradually. During the recovery period, the F/M wave amplitude ratio, which is an indicator of facial nucleus excitability, significantly increased on the impaired side but not on the intact side. This increase was most prominent within 3 weeks; thereafter, the ratio gradually decreased and reached the levels recorded before facial nerve impairment by 7 weeks. Facial nerve impairment leads to hyperexcitability of the facial nucleus during the recovery period.

Intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus that project to the principal nucleus (Pr5) play an active role in shaping the receptive fields of other neurons, at different levels in the ascending sensory system that processes information originating from the vibrissae. By using retrograde labeling and digital reconstruction, we investigated the morphometry and topology of the dendritic trees of these neurons and the changes induced by long-term experience-dependent plasticity in adult male rats. Primary afferent input was either eliminated by transection of the right infraorbital nerve (IoN), or selectively altered by repeated whisker clipping on the right side. These neurons do not display asymmetries between sides in basic metric and topologic parameters (global number of trees, nodes, spines, or dendritic ends), although neurons on the left tend to have longer terminal segments. Ipsilaterally, both deafferentation (IoN transection) and deprivation (whisker trimming) reduced the density of spines, and the former also caused a global increase in total dendritic length and a relative increase in more complex arbors. Contralaterally, deafferentation reduced more complex dendritic trees, and caused a moderate decline in dendritic length and spatial reach, and a loss of spines in number and density. Deprivation caused a similar, but more profound, effect on spines. Our findings provide original quantitative descriptions of a scarcely known cell population, and show that denervation- or deprivation-derived plasticity is expressed not only by neurons at higher levels of the sensory pathways, but also by neurons in key subcortical circuits for sensory processing., (Copyright © 2013 Wiley Periodicals, Inc.)

Deafferentation of motoneurons after facial nerve injury is a well-documented phenomenon but whether synaptic inputs to facial motoneurons are completely restored after reinnervation is unknown. Here, we tested the hypothesis that deficits in motor performance after transection/suture of the facial nerve (facial-facial anastomosis, FFA) in adult rats are associated with incomplete recovery of synaptic inputs. At 2 months after FFA, we found, in congruence with previous results, that the amplitude of whisking had recovered to only 31 % of control (sham operation). In the same FFA-treated rats, estimates of number of chemically defined synaptic terminals in the facial nucleus by immunohistochemistry and stereology showed a significant loss, compared with sham controls, of glutamatergic terminals (-26 %) and cholinergic perisomatic boutons (-31 %), but not inhibitory (GABA/glycinergic) terminals (-14 %). Synaptic deficits were accompanied by persistent microgliosis in the facial nucleus but soma area, dendritic arbor volume, and total number of motoneurons were normal. Correlation analyses revealed significant co-variations of whisking amplitude with number of glutamatergic and cholinergic synapses. Compared with 2 months, analyses of animals at 4 months after FFA showed no attenuation of the functional deficit and structural aberrations with one exception, increase of inhibitory terminal numbers beyond control level (+11 %) leading to further reduction of the excitatory/inhibitory terminal ratio. We suggest that deficits in motoneuron innervation in the regenerated facial nucleus-reduced glutamatergic and cholinergic input and reduced excitatory/inhibitory terminal ratio-could attenuate the motor output and, thus, negatively impact the functional performance after facial nerve regeneration.

Adult mammalian brains undergo reorganization following deafferentations due to peripheral nerve, cortical or spinal cord injuries. The largest extent of cortical reorganization is seen in area 3b of the somatosensory cortex of monkeys with chronic transection of the dorsal roots or dorsal columns of the spinal cord. These injuries cause expansion of intact face inputs into the deafferented hand cortex, resulting in a change of representational boundaries by more than 7 mm. Here we show that large-scale reorganization in area 3b following spinal cord injuries is due to changes at the level of the brainstem nuclei and not due to cortical mechanisms. Selective inactivation of the reorganized cuneate nucleus of the brainstem eliminates observed face expansion in area 3b. Thus, the substrate for the observed expanded face representation in area 3b lies in the cuneate nucleus.

In preparation for the donor and recipient facial vascularized composite allotransplant (VCA), the marginal mandibular nerve branch should be identified and co-apted to the recipient's nerve to allow for re-innervation. We describe a method to identify the marginal mandibular branch of the facial nerve in facial VCA donors and recipients. Through cadaver dissections, the posterior facial vein was traced posteriorly to identify the marginal mandibular branch of the facial nerve. In cases where we were unable to use this relationship, we found the posterior facial venous system to be diminutive. This technique is useful for finding the marginal mandibular branch when dissecting anterograde to the parotid gland.

Backgrounds: ATP and P2X receptors play important roles in the modulation of trigeminal neuropathic pain, while the role of G protein-coupled P2Y₂ receptors and the underlying mechanisms are less clear. The threshold and frequency of action potentials, fast inactivating transient K+ channels (IA) are important regulators of membrane excitability in sensory neurons because of its vital role in the control of the spike onset. In this study, pain behavior tests, QT-RT-PCR, immunohistochemical staining, and patch-clamp recording, were used to investigate the role of P2Y₂ receptors in pain behaviour., Results: In control rats: 1) UTP, an agonist of P2Y₂/P2Y₄ receptors, caused a significant decrease in the mean threshold intensities for evoking action potentials and a striking increase in the mean number of spikes evoked by TG neurons. 2) UTP significantly inhibited IA and the expression of Kv1.4, Kv3.4 and Kv4.2 subunits in TG neurons, which could be reversed by the P2 receptor antagonist suramin and the ERK antagonist U0126. In ION-CCI (chronic constriction injury of infraorbital nerve) rats: 1) mRNA levels of Kv1.4, Kv3.4 and Kv4.2 subunits were significantly decreased, while the protein level of phosphorylated ERK was significantly increased. 2) When blocking P2Y₂ receptors by suramin or injection of P2Y2R antisense oligodeoxynucleotides both led to a time- and dose-dependent reverse of allodynia in ION-CCI rats. 3) Injection of P2Y₂ receptor antisense oligodeoxynucleotides induced a pronounced decrease in phosphorylated ERK expression and a significant increase in Kv1.4, Kv3.4 and Kv4.2 subunit expression in trigeminal ganglia., Conclusions: Our data suggest that inhibition of P2Y₂ receptors leads to down-regulation of ERK-mediated phosphorylation and increase of the expression of I(A)-related Kv channels in trigeminal ganglion neurons, which might contribute to the clinical treatment of trigeminal neuropathic pain.

Background: Selective inferior orbital fissure (IOF) content transection for the purpose of surgical access to the posterior orbital floor is a technique that facilitates visualization of the posterior bony ledges of traumatic orbital floor defects. It also has potential advantages in achieving stable placement of reconstructive materials. Although not new, the surgical technique has not yet been described, and the morbidity of the technique has not been quantified. This article describes the procedure and assesses the morbidity specific to the division of related neural structures., Methods: The technique and surgical anatomy are described and illustrated with intraoperative photographs. Postoperative assessment of neural structures relevant to the division of IOF contents is performed. These values are compared with the nonoperated side to evaluate the morbidity of the technique., Results: The technique, which is consistently used by the senior author in the repair of orbital floor defects with very small posterior ledges or which extend to and involve the IOF, facilitates better visualization of the posterior ledge and posterolateral ledge in such cases. Surgical outcomes including facial sensation and lacrimal function on the operated side remain within the reference range and are not significantly different when compared with the contralateral nonoperated side., Conclusions: Selective IOF transection aids in the direct visualization of the posterior bony ledges in the repair of posterior orbital floor defects. It therefore may facilitate the placement of reconstructive materials on bony ledges circumferentially, providing stable reconstruction, potentially reducing implant-related complications without causing increased morbidity.

We placed injections of anatomical tracers into representations of the tongue, teeth, and face in the primary somatosensory cortex (area 3b) of macaque monkeys. Our injections revealed strong projections to representations of the tongue and teeth from other parts of the oral cavity responsive region in 3b. The 3b face also provided input to the representations of the intraoral structures. The primary representation of the face showed a pattern of intrinsic connections similar to that of the mouth. The area 3b hand representation provided little to no input to either the mouth or the face representations. The mouth and face representations of area 3b received projections from the presumptive oral cavity and face regions of other somatosensory areas in the anterior parietal cortex and the lateral sulcus, including areas 3a, 1, 2, the second somatosensory area (S2), the parietal ventral area (PV), and cortex that may include the parietal rostral (PR) and ventral somatosensory (VS) areas. Additional inputs came from primary motor (M1) and ventral premotor (PMv) areas. This areal pattern of projections is similar to the well-studied pattern revealed by tracer injections in regions of 3b representing the hand. The tongue representation appeared to be unique in area 3b in that it also received inputs from areas in the anterior upper bank of the lateral sulcus and anterior insula that may include the primary gustatory area (area G) and other cortical taste-processing areas, as well as a region of lateral prefrontal cortex (LPFC) lining the principal sulcus., (Copyright © 2013 Wiley Periodicals, Inc.)

In search for new biomarkers of vascular disturbances accompanying migraine, we compared the facial and hand skin temperatures in 41 women, including 12 migraine patients during the headache-free period and 29 healthy controls. Compared to the controls, the acral skin temperatures were lower in migraineurs, especially in those with right-sided headache. Our findings suggest that migraine is associated with a peripheral coldness possibly due to abnormal autonomic vascular control. The cold nose and hands may represent easily assessable biomarkers of these disorders., (© 2013.)