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1.
Restor Neurol Neurosci ; 37(4): 409-419, 2019.
Article in English | MEDLINE | ID: mdl-31322584

ABSTRACT

BACKGROUND: Nerve reconstructive surgery induces a transient loss and a prolonged and a gradual return of sensory inputs to the brain. It is unknown whether, following this massive peripheral denervation, the brain will experience a prolonged period of severe, intrinsic dysfunction. OBJECTIVE: We aim to investigate the mechanisms of return of processing function in cortical neurons. METHODS: We used the whisker model in rats to evaluate the functional recovery in the somatosensory cortex after a nerve reconstruction surgery. Multi-unit recording in the barrel cortex was performed in lightly anesthetized rats while their whiskers were stimulated by a whisker stimulator. RESULTS: We observed a loss of neuronal responses to whisker stimulation 1 week after surgery, which started to recover 2 weeks after surgery. Following the surgery, only 11.8% of units had principle whiskers (PWs) returned to their original status while 17.7% had PWs different from their original status, indicating the effect of aberrant reinnervation on the whisker response map. CONCLUSIONS: Robust neuronal responses to sensory stimulation even when only sparse sensory inputs are available in the early recovery phase. During this phase, aberrant reinnervation induces disorganized whisker tuning, a finding that might be account for the hypoesthesia and paresthesia during early recovery after nerve reconstruction.


Subject(s)
Maxillary Nerve/physiopathology , Plastic Surgery Procedures , Recovery of Function/physiology , Somatosensory Cortex/physiopathology , Vibrissae/innervation , Vibrissae/physiology , Animals , Physical Stimulation , Rats
2.
Br J Neurosurg ; 33(4): 409-412, 2019 Aug.
Article in English | MEDLINE | ID: mdl-30431370

ABSTRACT

Background: The chronic constriction injury (CCI) of the infraorbital nerve (ION) has been used to establish an animal mode of trigeminal neuralgia (TN), but key parameters of the model have not been quantified until now. Objective: The aim of the study was to quantify a standard of pain threshold to evaluate a successful TN model in Sprague-Dawley (SD) rats. Methods: Forty-eight adult SD rats (200-220 g) underwent chronic constriction injury of the infraorbital nerve. The pain threshold was tested one day preoperatively (baseline) and day 1, 3, 7, 14, 28 postoperatively using the up-down method. At day 28, all the animals were killed by dislocation of the cervical spine and the trigeminal nerve specimens were removed for electron microscopy. Results: The baseline pain threshold was 14.40 ± 0.87 g. Postoperatively, all the rats presented an initial reduced sensitivity to mechanical stimulation from day 1 (15.63 ± 1.92 g) through 7 (17.39 ± 1.43 g) after the surgery. At day 14, 32 (66.7%) began to show significant mechanical allodynia (0.71 ± 0.43 g) which did not change significantly till day 28 (0.88 ± 0.54 g). These animals were regarded as successful TN models with a 95% confidence interval of the pain threshold of 0.58-1.27 at Day 14. The electron microscopy demonstrated homogeneously demyelinated changes in those successful TN model animals rather than severe or mild epineurial lesions in those unsuccessful model animals. Conclusion: Our study showed that an animal TN model could be established with a two-week chronic constriction injury of the infraorbital nerve. The mechanical allodynia index <1.27 at Day 14 was suggested as a criterion for a successful model.


Subject(s)
Pain Threshold/physiology , Trigeminal Nerve Injuries/physiopathology , Trigeminal Neuralgia/physiopathology , Animals , Constriction , Disease Models, Animal , Hyperalgesia/etiology , Maxillary Nerve/injuries , Maxillary Nerve/physiopathology , Rats, Sprague-Dawley , Trigeminal Nerve/physiology , Trigeminal Neuralgia/etiology
3.
Physiol Behav ; 194: 497-504, 2018 10 01.
Article in English | MEDLINE | ID: mdl-29928887

ABSTRACT

We explored the molecular and behavioral effects of a perineural Lipopolysaccharide (LPS)-mediated inflammatory priming on the development and maintenance of painful post-traumatic trigeminal neuropathy (PPTTN) following infra-orbital nerve chronic constriction injury (CCI-IoN) in rats. Rats were pretreated with repetitive perineural injections in the vicinity of the IoN of either LPS or vehicle (Vhcl) before being submitted to CCI-IoN. Orofacial pain-like behaviors (response to Von Frey Filament testing and spontaneous isolated face grooming) were measured during the period of LPS injections (three weeks) and following CCI-IoN surgery (two weeks). Local LPS administration induced an early pain-like behavior (i.e. an increase in spontaneous pain [SP] or mechanical static allodynia [MSA]) in both conditions, and following CCI-IoN, MSA and SP developed earlier and more severely in LPS-pretreated rats than in the control group. Ipsilateral increases of key neuropathic pain mRNA markers in the IoN parenchyma, trigeminal ganglia (TG) and spinal trigeminal nucleus caudalis (Sp5C) were observed in CCI-IoN injured animals as compared to controls. Although no significant molecular differences could be observed within the IoN parenchyma between LPS and Vhcl-pretreated animals, a significant increase of key inflammatory cytokine Interleukin 1 beta (IL - 1ß) could be found in the TG of LPS-pretreated CCI-injured animals versus controls. Finally, a higher increase of inducible nitric oxide synthase (iNOS) in ipsilateral Sp5C of LPS-pretreated animals was observed as compared to Sp5C of Vhcl-pretreated animals. These results suggest a key role of inflammatory priming in the development and maintenance of PPTTN implicating IL-1ß/iNOS-dependent central sensitization mechanisms.


Subject(s)
Inflammation/physiopathology , Lipopolysaccharides/pharmacology , Maxillary Nerve/physiopathology , Neuralgia/physiopathology , Trigeminal Nerve Injuries/physiopathology , Animals , Hyperalgesia/complications , Hyperalgesia/physiopathology , Inflammation/chemically induced , Inflammation/complications , Interleukin-1beta/metabolism , Male , Maxillary Nerve/metabolism , Neuralgia/complications , Neuralgia/metabolism , Nitric Oxide Synthase Type II/metabolism , Pain Measurement , Peripheral Nerve Injuries/complications , Peripheral Nerve Injuries/physiopathology , Rats , Trigeminal Ganglion/metabolism , Trigeminal Nerve Injuries/complications , Trigeminal Nerve Injuries/metabolism , Trigeminal Nucleus, Spinal/metabolism
4.
Neurosci Lett ; 666: 120-126, 2018 02 14.
Article in English | MEDLINE | ID: mdl-29277624

ABSTRACT

BACKGROUND: To identify differences in allodynia and grooming behaviours between rat models of either repeated dural nociception with inflammatory soup (IS) or infraorbital nerve chronic constriction injury (IoN-CCI). METHODS: Repeated dural nociception was induced via the application of IS to the dural meninges and IoN-CCI was applied to model neuropathic pain. All surgeries were performed on the right side and a sham operation was performed on the control group. Mechanical and thermal withdrawal thresholds were tested on different facial areas and hindpaw during the interictal period and grooming behaviours were recorded. RESULTS: A significant decreases was found in the mechanical withdrawal thresholds of the bilateral vibrissa pad and right periorbital area in both the IS and the IoN-CCI groups, but only in the left periorbital area of the IS group. Hindpaw thermal allodynia was evident only in the IS group. Ipsilateral hindpaw grooming behaviour increased in the IS group and facial grooming behaviour increased in the IoN-CCI group. CONCLUSIONS: Repeated dural nociception induced by IS and IoN-CCI in rats effectively simulated chronic migraine (CM) and trigeminal neuralgia (TN), respectively. The IS group exhibited a wider range of allodynia than the IoN-CCI group, but further studies are necessary to determine underlying mechanisms.


Subject(s)
Hyperalgesia/physiopathology , Maxillary Nerve/physiopathology , Migraine Disorders/physiopathology , Neuralgia/physiopathology , Nociception/physiology , Animals , Constriction , Disease Models, Animal , Male , Rats, Wistar
5.
J Craniofac Surg ; 27(1): 61-3, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26716549

ABSTRACT

PURPOSE: The frequency of zygomaticomaxillary fracture is second only to nasal bone fracture. Up to 30% to 80% of zygomaticomaxillary fracture patients complain of sensory disturbance results from infraorbital nerve injury. The objective of this study was to detect what factors are related to infraorbital nerve recovery and specifically to investigate decompression of infraorbital foramen improves sensory recovery. PATIENTS AND METHODS: A total of 257 patients were assessed with unilateral zygomaticomaxillary complex fracture, treated with open reduction and internal fixation with orbital floor reconstruction. Of these, 166 patients followed up over 6 months were included in this study. The data collected included age, sex, pre, and postoperative sensory score measured by visual analogue scale (range: 0-10). Sensory score was measured at the infraorbital nerve innervation. The impact of decompression operation on the change of sensory score was compared. Statistical analysis was performed using SPSS 18.0 software (SPSS Inc, Chicago, IL). RESULTS: In patients with preoperative hypoesthesia, difference between postoperative and preoperative sensory score was 3.2 (decompression group), 4.4 (nondecompression group), respectively, but not significant (P > 0.05). In patients without preoperative hypoesthesia, difference between postoperative and preoperative sensory score was -0.2 (decompression group), -0.3 (nondecompression group), respectively, and did not show significant association (P > 0.05). DISCUSSION: Based on this result, in patients with preoperative hypoesthesia, infraorbital decompression operation is not useful for sensory recovery. This result indicates infraorbital sensory disturbance occurs from not only pinched nerve injury at the infraorbital foramen but also traction nerve injury at the other part of the nerve.


Subject(s)
Decompression, Surgical/methods , Maxillary Fractures/surgery , Orbit/innervation , Zygomatic Fractures/surgery , Adult , Female , Follow-Up Studies , Fracture Fixation, Internal/methods , Humans , Hypesthesia/surgery , Male , Maxillary Nerve/injuries , Maxillary Nerve/physiopathology , Orbit/injuries , Orbit/surgery , Plastic Surgery Procedures/methods , Recovery of Function/physiology , Sensation/physiology , Visual Analog Scale
6.
Pain Pract ; 16(3): 305-10, 2016 Mar.
Article in English | MEDLINE | ID: mdl-25727990

ABSTRACT

OBJECTIVE: The aim of this study was to investigate whether antidromic conduction monitoring (ACM) can be utilized to map the trigeminal system under sedation as a potential substitute for subjective paresthesia description (SPD) during percutaneous ganglion radiofrequency thermocoagulation (PGRT). METHODS: Eighty-two patients with 152 pain divisions of trigeminal neuralgia (TN) were treated by computed tomography (CT)-guided PGRT. After the puncture needle entered the foramen ovale (FO), sensory and motor stimulation were applied to locate the pain division. And the corresponding voltage values were recorded by patients' SPD. In the following, the proper location was certified by ACM. The corresponding earliest waves and voltage values in the identified trigeminal branch were also recorded to outline a comparison between two methods. RESULTS: The correlation of ACM and patients' SPD with voltage at ≤ 0.5 V was statistically significant (P < 0.05, r = 0.159; Spearman's rank correlation analysis). Although ACM and SPD showed weak correlation, as their interclass correlation coefficient was significant (F = 1.868, P < 0.01) with coefficient of internal consistency. Moreover, the two methods had consistency. Kruskal-Wallis test showed that ophthalmic (V1), maxillary (V2), and mandibular (V3) divisions had significant differences for test sensitivity (H = 15.945, P < 0.01). For comparison of sensitivities with ACM, V3 was most sensitive followed by V2 and then V1. CONCLUSION: ACM could potentially substitute for SPD of the paresthesias intra-operatively, enabling greater specificity and eliminating the need to interrupt the administration of anesthetic. These improvements would increase patient satisfaction and practitioner efficiency and accuracy.


Subject(s)
Electrocoagulation/methods , Neural Conduction , Trigeminal Ganglion/surgery , Trigeminal Neuralgia/surgery , Adult , Aged , Aged, 80 and over , Electromyography , Female , Humans , Male , Mandibular Nerve/physiopathology , Maxillary Nerve/physiopathology , Middle Aged , Ophthalmic Nerve/physiopathology , Paresthesia/diagnosis , Radio Waves , Trigeminal Ganglion/physiopathology , Trigeminal Neuralgia/physiopathology
7.
Article in Chinese | MEDLINE | ID: mdl-26514011

ABSTRACT

Patients of infraorbital nerve injury often appear in the sensory abnormalities of corresponding position, such as numbness or pain. We present a case with numbness of the left cheek because of the injury. The patient were treated by endoscopic assisted on the left infraorbital nerve decompression through the approach of the canine fossa. The symptom shows improvement after the operation. The patient feels numbness significantly ease on 4 months after the operation.


Subject(s)
Decompression, Surgical , Endoscopy , Maxillary Nerve/physiopathology , Humans , Maxillary Nerve/surgery , Paresthesia
8.
Pain Physician ; 18(5): E795-804, 2015.
Article in English | MEDLINE | ID: mdl-26431133

ABSTRACT

BACKGROUND: There is no truly optimal treatment to cure refractory neuralgia of the infraorbital nerve. Recently, nondestructive pulsed radiofrequency (PRF) has become one of the most attractive interventional techniques for painful disorders. However, use of the technique for infraorbital neuralgia has been seldom reported. OBJECTIVE: The purpose of this prospective study is to observe the effectiveness and safety of PRF treatment for neuralgia of the infraorbital nerve. STUDY DESIGN: Prospective case series clinical outcome study. SETTING: University Medical Center, Beijing, China. METHODS: From January 2011 to November 2012, 36 consecutive patients, following ineffective conservative therapy, underwent PRF treatment and completed 2-year follow-up. Numeric rating scales (NRS), effective rate, additional carbamazepine dosage, and side effects were recorded at postoperative day one, week one, week 2, month one, month 3, month 6, year one, and year 2. Patients were divided into effective group and ineffective group based on postoperative one -month total pain relief or more than 50% reduction in NRS and patients were satisfied with the effect, and possible factors affecting efficacy were compared between the 2 groups. RESULTS: Effective rates were 69%, 69%, 64%, 50%, and 50% at postoperative month one, month 3, month 6, year one, and year 2, respectively. No serious side effects were observed, except that 9 patients felt short-term (one -month duration) mild numbness. Output voltage and tissue resistance in the effective group were significantly higher than the ineffective group (P < 0.01). Intraoperative output voltage was negatively correlated with postoperative one -month NRS (r = -0.332, P < 0.05). LIMITATIONS: The non-controlled and single-centered design of the study. CONCLUSIONS: Results demonstrated PRF treatment under computed tomography (CT) guidance for infraorbital neuralgia is safe, effective, and is expected to become an alternative for patients experiencing ineffective conservative therapy. Increasing the output voltage of PRF could be the chosen method to improve the efficacy.


Subject(s)
Cranial Nerve Diseases/therapy , Maxillary Nerve/physiopathology , Neuralgia/therapy , Outcome Assessment, Health Care , Pulsed Radiofrequency Treatment/adverse effects , Pulsed Radiofrequency Treatment/methods , Aged , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pilot Projects , Tomography, X-Ray Computed
9.
J Ir Dent Assoc ; 61(1): 34-5, 2015.
Article in English | MEDLINE | ID: mdl-26281623

ABSTRACT

Paraesthesia can be a complication of surgical intervention. Its occurrence after dental local anaesthetic use is a rare event in general dental practice. Reported cases have mainly described its presentation for the mandibular division of the trigeminal nerve with very few reports for the maxillary division of this nerve. This report describes a case of paraesthesia in the maxillary region following local anaesthetic use prior to removal of an upper molar tooth.


Subject(s)
Anesthesia, Dental/adverse effects , Anesthetics, Local/adverse effects , Lidocaine/adverse effects , Maxillary Nerve/physiopathology , Paresthesia/etiology , Adult , Female , Follow-Up Studies , Gingiva/innervation , Humans , Lip/innervation , Molar/surgery , Periapical Diseases/surgery , Tooth Extraction/methods
10.
Curr Pain Headache Rep ; 19(9): 44, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26210355

ABSTRACT

"Numb chin syndrome" (NCS) refers to new-onset numbness of the lower lip and chin within the distribution of the mental or inferior alveolar nerves. While this focal numbness may be downplayed or even overlooked by patients and clinicians, in the right clinical scenario this may be the presenting symptom of an underlying malignancy. In the absence of any obvious, temporally related dental cause, there are certain conditions that clinicians should consider including orofacial and systemic malignancies as well as several inflammatory disorders. Thorough diagnostic evaluation should always be performed when no clear cause is evident. This paper will discuss the differential, recommended evaluations, and the prognosis, for a patient presenting with NCS.


Subject(s)
Chin/innervation , Cranial Nerve Diseases/complications , Hypesthesia/etiology , Mandibular Diseases/complications , Neoplasms/complications , Nerve Compression Syndromes/complications , Biomarkers/blood , Cranial Nerve Diseases/diagnosis , Cranial Nerve Diseases/physiopathology , Diagnosis, Differential , Humans , Hypesthesia/physiopathology , Magnetic Resonance Imaging , Mandibular Diseases/diagnosis , Mandibular Diseases/physiopathology , Mandibular Nerve/physiopathology , Maxillary Nerve/physiopathology , Multimodal Imaging , Neoplasms/diagnosis , Neoplasms/physiopathology , Nerve Compression Syndromes/diagnosis , Nerve Compression Syndromes/physiopathology , Positron-Emission Tomography , Practice Guidelines as Topic , Prognosis , Syndrome , Tomography, X-Ray Computed
11.
J Pain ; 16(4): 335-45, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25640293

ABSTRACT

UNLABELLED: Anecdotally, orofacial pain patients sometimes report that the painful face area feels "swollen." Because there are no clinical signs of swelling, such illusions may represent perceptual distortions. In this study, we examine whether nociceptive stimulation can lead to perceptual distortion of the face in a way similar to that of local anesthesia. Sixteen healthy participants received injections of .4 mL hypertonic saline to induce short-term nociceptive stimulation, .4 mL mepivacaine (local anesthetic) to transiently block nerve transduction, and .4 mL isotonic saline as a control condition. Injections were administered in both the infraorbital and the mental nerve regions. Perceptual distortions were conceptualized as perceived changes in magnitude of the injected areas and the lips, and they were measured using 1) a verbal subjective rating scale and 2) a warping procedure. Prior to the study, participants filled in several psychological questionnaires. This study shows that both nociceptive stimulation (P < .05) and transient blocking of nerve transduction (P < .05) can lead to perceptual distortion of the face. A test-retest experiment including 9 new healthy subjects supported the results. Perceptual distortions were positively correlated with the psychological variable of dissociation in several conditions (P < .05). Perceptual distortions may therefore be influenced by somatosensory changes and psychological mechanisms. PERSPECTIVE: Knowledge of the factors that influence the perception of the face is important to understand the possible implications of perceptual distortions in orofacial pain disorders (and possibly other chronic pain states). Such information may ultimately open up new avenues of treatment for persistent orofacial pain.


Subject(s)
Anesthetics, Local/pharmacology , Facial Pain/physiopathology , Mandibular Nerve/drug effects , Maxillary Nerve/drug effects , Mepivacaine/pharmacology , Perceptual Disorders/physiopathology , Face/physiopathology , Facial Pain/psychology , Female , Humans , Male , Mandibular Nerve/physiopathology , Maxillary Nerve/physiopathology , Nerve Block , Nociceptive Pain/physiopathology , Nociceptive Pain/psychology , Pain Measurement , Pain Perception/drug effects , Pain Perception/physiology , Perception/drug effects , Perception/physiology , Perceptual Disorders/chemically induced , Reproducibility of Results , Saline Solution, Hypertonic , Surveys and Questionnaires , Young Adult
12.
J Craniomaxillofac Surg ; 43(2): 244-7, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25547215

ABSTRACT

The purpose of this study was to retrospectively analyse patients with orbital floor fracture who were treated at the Department of Odontostomatology and Maxillofacial Surgery, Policlinico Umberto I, Sapienza University of Rome, Italy, between 2008 and 2013. Patients were evaluated by age, sex, aetiology, clinical findings, fracture pattern, ocular injury, treatment, complications, and sequelae. We evaluated surgical outcomes and complications with the use of different surgical approaches and various materials used to reconstruct the orbital floor. In total, there were 301 orbital fractures. Two hundred and seventeen patients were men (72.1%) and 84 were women (27.9%). The average age of the patients was 37.2 years (range, 9-90 years). The leading cause of these fractures was violent assault (27.3%). Pure blow-out fractures (50.2%) were the most represented pattern, followed by zygomatic complex (46.5%). The most common symptom was hypoesthesia extending through the territory of the second trigeminal branch (TBH; 32.9%). Diplopia was present in 20.2% of patients followed by enophthalmos (2.3%) and extraocular movement limitation (1.7%). Ocular symptoms significantly improved following surgical repair. The most common postoperative complications included TBH in 34.2%, scarring 26%, and diplopia in 16.4% of the patients.


Subject(s)
Orbital Fractures/epidemiology , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Child , Cicatrix/epidemiology , Diplopia/epidemiology , Enophthalmos/epidemiology , Female , Humans , Hypesthesia/epidemiology , Italy/epidemiology , Male , Maxillary Nerve/physiopathology , Middle Aged , Ocular Motility Disorders/epidemiology , Orbital Fractures/surgery , Postoperative Complications/epidemiology , Plastic Surgery Procedures/statistics & numerical data , Retrospective Studies , Sex Factors , Treatment Outcome , Violence/statistics & numerical data , Young Adult , Zygomatic Fractures/epidemiology
13.
J Neurosurg ; 121(6): 1497-503, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25280092

ABSTRACT

OBJECT: The objective of this study was to develop an electrophysiological method for intraoperative localization of the trigeminal nerve branches during radiofrequency thermocoagulation (RFTC). METHODS: Twenty-three patients who were scheduled to undergo RFTC were included. The trigeminal nerve root was stimulated through the foramen ovale using the radiofrequency cannula. Antidromic responses were recorded from the target division through supraorbital, infraorbital, and mental foramina electrodes, and an additional electrode at the masseter muscle. Sensory and motor action responses, as well as verbal and masseter contraction responses, were recorded and correlated. RESULTS: The antidromic responses were easily recorded in the target division in all 23 patients, and they were invariably correlated with the patient's verbal responses. The potentials were recorded successively from V1 to V3. The amplitude in each division before and after RFTC showed little difference in response to electrical stimulation with the same current. The motor trigeminal nerve action potentials were recorded in 10 patients; 7 of these patients had postoperative masseter muscle weakness, while the remaining 3 had normal masseter muscle function. Potentials with low amplitudes were usually obtained from neighboring divisions, but no unexpected denervation of any branches was observed. All the patients experienced immediate pain relief after the procedure. CONCLUSIONS: This technique is sensitive and easy to apply. The sensory and motor potentials matched the verbal responses and the complications. Although it cannot completely substitute for the patient's verbal response, this approach is helpful in uncooperative patients, and it predicts and reduces the incidence of masseter muscle weakness. The use of these complementary techniques could increase the chances of treatment success.


Subject(s)
Electrocoagulation/methods , Evoked Potentials, Motor , Evoked Potentials, Somatosensory , Trigeminal Nerve/anatomy & histology , Trigeminal Nerve/surgery , Trigeminal Neuralgia/surgery , Action Potentials , Adult , Aged , Electromyography/methods , Female , Humans , Male , Mandibular Nerve/anatomy & histology , Mandibular Nerve/physiopathology , Mandibular Nerve/surgery , Maxillary Nerve/anatomy & histology , Maxillary Nerve/physiopathology , Maxillary Nerve/surgery , Middle Aged , Ophthalmic Nerve/anatomy & histology , Ophthalmic Nerve/physiopathology , Ophthalmic Nerve/surgery , Trigeminal Nerve/physiopathology , Trigeminal Neuralgia/physiopathology
14.
Eur J Neurosci ; 39(12): 2050-9, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24666367

ABSTRACT

To evaluate the mechanisms underlying orofacial motor dysfunction associated with trigeminal nerve injury, we studied the astroglial cell activation following chronic constriction injury (CCI) of the infraorbital nerve (ION) immunohistochemically, nocifensive behavior in ION-CCI rats, and the effect of the glutamine synthase (GS) blocker methionine sulfoximine (MSO) on the jaw-opening reflex (JOR), and also studied whether glutamate-glutamine shuttle mechanism is involved in orofacial motor dysfunction. GFAP-immunoreactive (IR) cells were observed in the trigeminal motor nucleus (motV) 3 and 14 days after ION-CCI, and the nocifensive behavior and JOR amplitude were also strongly enhanced at these times. The number of GS- and GFAP-IR cells was also significantly higher in ION-CCI rats on day 7. The amplitude and duration of the JOR were strongly suppressed after MSO microinjection (m.i.) into the motV compared with that before MSO administration in ION-CCI rats. After MSO administration, the JOR amplitude was strongly suppressed, and the duration of the JOR was shortened. Forty minutes after m.i. of glutamine, the JOR amplitude was gradually returned to the control level and the strongest attenuation of the suppressive effect of MSO was observed at 180 min after glutamine m.i. In addition, glutamine also attenuated the MSO effect on the JOR duration, and the JOR duration was extended and returned to the control level thereafter. The present findings suggest that astroglial glutamate-glutamine shuttle in the motV is involved in the modulation of excitability of the trigeminal motoneurons affecting the enhancement of various jaw reflexes associated with trigeminal nerve injury.


Subject(s)
Astrocytes/physiology , Glutamic Acid/metabolism , Jaw/physiopathology , Maxillary Nerve/injuries , Maxillary Nerve/physiopathology , Reflex/physiology , Animals , Constriction, Pathologic , Enzyme Inhibitors/pharmacology , Glial Fibrillary Acidic Protein/metabolism , Glutamate-Ammonia Ligase/antagonists & inhibitors , Glutamate-Ammonia Ligase/metabolism , Jaw/drug effects , Male , Mandibular Nerve/drug effects , Mandibular Nerve/physiopathology , Maxillary Nerve/drug effects , Methionine Sulfoximine/pharmacology , Movement Disorders/etiology , Movement Disorders/physiopathology , Muscle, Skeletal/drug effects , Muscle, Skeletal/physiopathology , Rats, Sprague-Dawley , Reflex/drug effects , Skin Physiological Phenomena/drug effects , Trigeminal Motor Nucleus/drug effects , Trigeminal Motor Nucleus/physiopathology
15.
J Neurophysiol ; 111(8): 1590-600, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24478162

ABSTRACT

Infraorbital nerve (ION) transection in neonatal rats leads to disruption of whisker-specific neural patterns (barrelettes), conversion of functional synapses into silent synapses, and reactive gliosis in the brain stem trigeminal principal nucleus (PrV). Here we tested the hypothesis that neonatal peripheral nerve crush injuries permit better functional recovery of associated central nervous system (CNS) synaptic circuitry compared with nerve transection. We developed an in vitro whisker pad-trigeminal ganglion (TG)-brain stem preparation in neonatal rats and tested functional recovery in the PrV following ION crush. Intracellular recordings revealed that 68% of TG cells innervate the whisker pad. We used the proportion of whisker pad-innervating TG cells as an index of ION function. The ION function was blocked by ∼64%, immediately after mechanical crush, then it recovered beginning after 3 days postinjury and was complete by 7 days. We used this reversible nerve-injury model to study peripheral nerve injury-induced CNS synaptic plasticity. In the PrV, the incidence of silent synapses increased to ∼3.5 times of control value by 2-3 days postinjury and decreased to control levels by 5-7 days postinjury. Peripheral nerve injury-induced reaction of astrocytes and microglia in the PrV was also reversible. Neonatal ION crush disrupted barrelette formation, and functional recovery was not accompanied by de novo barrelette formation, most likely due to occurrence of recovery postcritical period (P3) for pattern formation. Our results suggest that nerve crush is more permissive for successful regeneration and reconnection (collectively referred to as "recovery" here) of the sensory inputs between the periphery and the brain stem.


Subject(s)
Maxillary Nerve/injuries , Neuronal Plasticity/physiology , Neurons/physiology , Peripheral Nerve Injuries/physiopathology , Recovery of Function/physiology , Trigeminal Nuclei/growth & development , Trigeminal Nuclei/physiopathology , Animals , Animals, Newborn , Maxillary Nerve/pathology , Maxillary Nerve/physiopathology , Maxillary Nerve/surgery , Nerve Crush , Neuroglia/physiology , Peripheral Nerve Injuries/pathology , Rats , Rats, Sprague-Dawley , Vibrissae/growth & development , Vibrissae/innervation
16.
Gerodontology ; 31(2): 89-94, 2014 Jun.
Article in English | MEDLINE | ID: mdl-23033842

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the diagnostic criteria and clinical presentations and compare the different treatment modalities in relation to prognosis in a sample of patients with the neuropathic disorder trigeminal neuralgia (TN). METHODS: A retrospective review study of clinical records was conducted of 92 patients diagnosed with TN. RESULTS: The mean age[±standard deviation (SD)] of the patients was 67.3±12.7 years with an average TN duration of 7.1±6 years and a female predominance (M:F=1:2.5). The maxillary branch was the most involved nerve (in 45% of patients). Twelve patients underwent CT scans, while thirty-six patients had MRIs. Carbamazepine used by 92.4% of patients was the most commonly used drug in the management of the disorder. Twenty-two patients had microvascular decompression (MVD). TN symptoms were completely relieved following surgery in 73% of patients who underwent neurosurgery. CONCLUSIONS: MRI is highly sensitive in the exclusion of central intracranial lesions and recommended as a routine consideration during the assessment of TN patients. Despite the side effects, carbamazepine is the drug therapy of choice. MVD produces satisfactory relief of TN symptoms in the majority of cases and should be offered to young healthy patients.


Subject(s)
Trigeminal Neuralgia/diagnosis , Aged , Analgesics, Non-Narcotic/therapeutic use , Carbamazepine/therapeutic use , Drug Combinations , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging/methods , Male , Maxillary Nerve/physiopathology , Microvascular Decompression Surgery , Middle Aged , Neurosurgical Procedures , Retrospective Studies , Tomography, X-Ray Computed/methods , Treatment Outcome , Trigeminal Neuralgia/therapy
17.
J Am Osteopath Assoc ; 113(7): 564-7, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23843380

ABSTRACT

Whiplash injury is often caused by rear-end motor vehicle collisions. Symptoms such as neck pain and stiffness or arm pain or numbness are common with whiplash injury. The author reports a case of right facial numbness and right cheek pain after a whiplash injury. Osteopathic manipulative treatment techniques applied at the level of the cervical spine, suboccipital region, and cranial region alleviated the patient's facial symptoms by treating the right-sided strain of the trigeminal nerve. The strain on the trigeminal nerve likely occurred at the upper cervical spine, at the nerve's cauda, and at the brainstem, the nerve's point of origin. The temporal portion of the cranium played a major role in the strain on the maxillary.


Subject(s)
Hypesthesia/therapy , Manipulation, Osteopathic , Whiplash Injuries/metabolism , Accidents, Traffic , Face , Humans , Hypesthesia/physiopathology , Manipulation, Osteopathic/methods , Maxillary Nerve/physiopathology , Trigeminal Nerve/physiopathology , Whiplash Injuries/physiopathology
18.
BMC Neurosci ; 13: 150, 2012 Dec 13.
Article in English | MEDLINE | ID: mdl-23234480

ABSTRACT

BACKGROUND: Trigeminal nerve is a major source of the sensory input of the face, and trigeminal neuropathology models have been reported in rodents with injury to branches of the maxillary or mandibular division of the trigeminal nerve. Non-human primates are neuroanatomically more closely related to human than rodents; however, nerve injury studies in non-human primates are limited. RESULTS: We describe here a nerve injury model of maxillary nerve compression (MNC) in the cynomolgus macaque monkey, Macaca fascicularis, and the initial characterization of the consequences of damage to this trigeminal nerve branch. The nerve injury from the compression appeared to be mild, as we did not observe overt changes in home-cage behavior in the monkeys. When mechanical stimulation was applied to the facial area, monkeys with MNC displayed increased mechanical sensitivity, as the avoidance response scores were lower than those from the control animals. Such a change in mechanical sensitivity appeared to be somewhat bilateral, as the contralateral side also showed increased mechanical sensitivity, although the change on the ipsilateral side was more robust. Multiple-unit recording of the maxillary nerve showed a general pattern of increasing responsiveness to escalating force in mechanical stimulation on the contralateral side. Ipsilateral side of the maxillary nerve showed a lack of responsiveness to escalating force in mechanical stimulation, possibly reflecting a maximum stimulation threshold effect from sensitized nerve due to MNC injury. CONCLUSIONS: These results suggest that MNC may produce increased sensitivity of the ipsilateral maxillary nerve, and that this model may serve as a non-human primate model to evaluate the effect of injury to trigeminal nerve branches.


Subject(s)
Disease Models, Animal , Maxillary Nerve/injuries , Maxillary Nerve/physiopathology , Nerve Compression Syndromes/physiopathology , Sensation/physiology , Action Potentials/physiology , Animals , Avoidance Learning/physiology , Face/physiopathology , Macaca fascicularis , Male , Physical Stimulation/methods
19.
Bull Exp Biol Med ; 153(4): 526-9, 2012 Aug.
Article in English, Russian | MEDLINE | ID: mdl-22977862

ABSTRACT

Transection of the maxillary nerve initiates apoptosis of the maxillary sinus mucosa cells in rats. Significant activation of apoptosis and proapoptotic factor p53 was found in the epithelium during week 1 after nerve transection. In delayed period after injury, apoptotic cells predominated in the submucosa against the background of Bcl-2 hypoexpression.


Subject(s)
Apoptosis/physiology , Maxillary Nerve/physiopathology , Maxillary Sinus/cytology , Nasal Mucosa/injuries , Trigeminal Nerve Injuries/physiopathology , Animals , Immunohistochemistry , In Situ Nick-End Labeling , Maxillary Nerve/injuries , Maxillary Sinus/injuries , Proto-Oncogene Proteins c-bcl-2/metabolism , Rats , Tumor Suppressor Protein p53/metabolism
20.
Gerodontology ; 29(2): e611-7, 2012 Jun.
Article in English | MEDLINE | ID: mdl-21726275

ABSTRACT

OBJECTIVE: To describe the clinical characteristics and treatment of trigeminal neuralgia (TN) in a group of Thai patients. MATERIALS AND METHODS: Records of 188 patients with TN were reviewed retrospectively for patient demographics, the characteristics of the pain and treatment modalities. RESULTS: Of the 188 patients, 37.2% were men and 62.8% were women. The peak incidence (46.8%) was in the age range of 50-69 years. Pain occurred on the right side of the face more often than on the left (1.8:1). The mandibular division of the trigeminal nerve was the most frequently affected (30.3%), followed by the combined maxillary and mandibular divisions (29.3%) and the maxillary division alone (25%). The majority described their attack as a sharp pain (77.6%), and the most common primary locations were at previous extraction sites (40.5%). The most common triggers were chewing (61.2%) and speaking (47.3%). Carbamazepine was the most common prescribed drug (76.1%) for the initial treatment. Combination drug therapy was introduced when the monotherapy failed to control the pain. Surgical intervention was the alternative choice of treatment in refractory cases. CONCLUSION: TN affected women more than men, and this disorder occurred most frequently in patients aged 50 years and older. The mandibular division of the trigeminal nerve was most commonly involved.


Subject(s)
Trigeminal Neuralgia/epidemiology , Adult , Age Factors , Aged , Aged, 80 and over , Analgesics, Non-Narcotic/therapeutic use , Carbamazepine/therapeutic use , Chronic Disease , Cryosurgery/statistics & numerical data , Drug Therapy, Combination , Female , Humans , Incidence , Male , Mandibular Nerve/physiopathology , Mastication/physiology , Maxillary Nerve/physiopathology , Middle Aged , Muscle Relaxants, Central/therapeutic use , Phenytoin/therapeutic use , Retrospective Studies , Sex Factors , Speech/physiology , Thailand/epidemiology , Tooth/innervation , Tooth Extraction/statistics & numerical data , Young Adult
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