Neurosensory changes in the infraorbital nerve following zygomatic fractures

Other Secondary Headaches: Odontogenic Pain and Other Painful Orofacial Conditions

This article discusses extremely common odontogenic pain conditions, which may occasionally present to the neurology clinic mimicking headache, and other uncommon orofacial pain conditions, which may do the same. Typical presentations, investigative strategies, and management are discussed, as well as highlighting key diagnostic criteria and the importance of involving oral or dental specialists where diagnostic uncertainty exists.

Pharmacological Topical Therapy for Intra-Oral Post Traumatic Trigeminal Neuropathic Pain: A Comprehensive Review

Background: The efficacy of topical treatments in alleviating neuropathic pain is well-established. However, there is a paucity of research on topical interventions designed specifically for intra-oral application, where the tissue composition differs from that of exposed skin. Methods: This comprehensive review endeavors to assess the extant evidence regarding the efficacy of topical treatments in addressing neuropathic pain within the oral cavity. Utilizing combinations of search terms, we conducted a thorough search across standard electronic bibliographic databases-MEDLINE (via PubMed), Embase, Google Scholar, and Up to Date. The variables under scrutiny encompassed topical treatment, local intervention, chronic oral and orofacial pain, and neuropathic pain. All pertinent studies published in the English language between 1992 and 2022 were included in our analysis. Results: Fourteen relevant manuscripts were identified, primarily consisting of expert opinions and case reports. The comprehensive review suggests that topical treatments, especially when applied under a stent, could be effective in mitigating neuropathic pain in the oral area. However, it is crucial to conduct further studies to confirm these preliminary results. The limitations of the reviewed studies, mainly the reliance on expert opinions, small sample sizes, inconsistent study designs, and a lack of long-term follow-up data, highlight the need for more rigorous research. Conclusions: Although initial findings indicate topical treatments may be effective for oral neuropathic pain, the limitations of current studies call for more thorough research. Further comprehensive studies are essential to validate the efficacy of these treatments, standardize procedures, and determine long-term results. This will provide clearer guidance for treating chronic neuropathic pain in the oral cavity.

Exploring the Effect of Ethnicity on Chronic Orofacial Pain: A Comparative Study of Jewish and Arab Israeli Patients

The relationship between ethnicity and chronic pain has been studied worldwide. The population of Israel includes two main ethnic groups, 75% Jews and 21% Arabs. The purpose of this study was to compare orofacial chronic pain characteristics and treatment outcomes between Jewish and Arab Israeli citizens. Two hundred patients admitted to the Orofacial Pain Clinic at Hebrew University-Hadassah School of Dental Medicine between 2017 and 2022 were selected randomly for this historical cohort study. Our cohort included 159 (79.5%) Jews and 41 (20.5%) Arabs. Twenty-six pain-related variables were compared of which only two differed significantly between the two groups, awakening due to pain and mean muscle sensitivity; both indicators were higher in the Arab group (p < 0.05). No differences were found in any of the other variables such as diagnosis, pain severity, onset, and treatment outcome. This minimal difference may be explained by the equal accessibility to medical services for all citizens, and the diversity of our staff that includes Jew as well as Arab service providers. These factors minimize or even eliminate racial bias, language, and cultural barriers, and is reflected in the minor differences in orofacial pain characteristics found between the two main ethnic groups in Israel.

Is Surgical Repair With Nerve Allograft More Cost-Effective Than Non-Surgical Management for Persistent Trigeminal Neuropathy? Initial Assessment With Markov Model

PURPOSE

Persistent trigeminal neuropathy (PTN) is associated with high rates of depression, loss of work, and decreased quality of life (QoL). Nerve allograft repair can achieve functional sensory recovery in a predictable manner; however, it bears significant upfront costs. In patients suffering from PTN, is surgical repair with allogeneic nerve graft, when compared to non-surgical therapy, a more cost-effective treatment option?

MATERIALS AND METHODS

A Markov model was constructed with TreeAge Pro Healthcare 2022 (TreeAge Software, Massachusetts) to estimate the direct and indirect costs for PTN. The model ran for 40 years with 1-year-cycles on a 40-year-old model patient with persistent inferior alveolar or lingual nerve injury (S0 to S2+) at 3 months without signs of improvement, and without dysesthesia or neuropathic pain (NPP). The 2 treatment arms were surgery with nerve allograft versus non-surgical management. There were 3 disease states, functional sensory recovery (S3 to S4), hypoesthesia/anesthesia (S0 to S2+), and NPP. Direct surgical costs were calculated using the 2022 Medicare Physician Fee Schedule and verified with standard institutional billing practices. Non-surgical treatment direct costs (follow-up, specialist referral, medications, imaging) and indirect costs (QoL, loss of employment) were determined from historical data and the literature. Direct surgical costs for allograft repair were $13,291. State-specific direct costs for hypoesthesia/anesthesia were $2,127.84 per year, and $3,168.24 for NPP per year. State-specific indirect costs included decreased labor force participation, absenteeism, and decreased QoL.

RESULTS

Surgical treatment with nerve allograft was more effective and had a lower long-term cost. The incremental cost-effectiveness ratio was -10,751.94, indicating surgical treatment should be utilized based on efficiency and cost. With a willingness-to-pay threshold of $50,000, the net monetary benefits of surgical treatment are $1,158,339 compared to $830,654 for non-surgical treatment. With a standard threshold incremental cost-effectiveness ratio of 50,000, the sensitivity analysis shows that surgical treatment would remain the preferred choice based on efficiency even if surgical costs were doubled.

CONCLUSION

Despite high initial costs of surgical treatment with nerve allograft for PTN, surgical intervention with nerve allograft is a more cost-effective treatment option when compared to non-surgical therapy.

Pathophysiology of Post-Traumatic Trigeminal Neuropathic Pain

Trigeminal nerve injury is one of the causes of chronic orofacial pain. Patients suffering from this condition have a significantly reduced quality of life. The currently available management modalities are associated with limited success. This article reviews some of the common causes and clinical features associated with post-traumatic trigeminal neuropathic pain (PTNP). A cascade of events in the peripheral and central nervous system function is involved in the pathophysiology of pain following nerve injuries. Central and peripheral processes occur in tandem and may often be co-dependent. Due to the complexity of central mechanisms, only peripheral events contributing to the pathophysiology have been reviewed in this article. Future investigations will hopefully help gain insight into trigeminal-specific events in the pathophysiology of the development and maintenance of neuropathic pain secondary to nerve injury and enable the development of new therapeutic modalities.

Neurosensory Assessment of Infraorbital Nerve Injury Following Unilateral Zygomaticomaxillary Complex Fracture – A Prospective Study

Background:

This study aimed to assess the difference in the recovery pattern of branches of infraorbital nerve paraesthesia after zygomaticomaxillary complex (ZMC) fracture in both surgically and non-surgically managed patients.

Materials & Methods:

A prospective, observational study involving 31 patients with unilateral ZMC fracture - 15 in the surgical group (Group A) and 16 in the non-surgical group (Group B) was evaluated. These patients were assessed at the time of injury, 3-months follow-up, and 6-months follow-up for the sensory function of the infraorbital nerve. The assessment of paraesthesia by cotton wisp test, light touch monofilament test, and the cold thermal test was subjected to intra-group and inter-group correlation by McNemar test and Fischer's exact test. Repeated Measures ANOVA with post-hoc Bonferroni test for intra-group correlation and independent sample t-test for inter-group correlation were used for two-point discrimination.

Results:

A statistically significant improvement was noted on both 3 and 6 months follow-up in the malar region in group A. Other statistically significant improvements were noted only on 6 months follow-up in the infraorbital region in group A. On the 2-point discrimination test, all the facial regions showed significant improvement in both the groups over 3 months and 6 months of follow-up.

Conclusion:

There was a significant improvement in the infraorbital nerve sensory function following ZMC fracture over 6 months; however, the surgical intervention showed no statistical significance. Further, it can also be concluded that the inferior palpebral branch of the infraorbital nerve shows maximum functional disruption resulting in a higher incidence of paraesthesia in the infraorbital and malar region.

Evaluation of Infraorbital Nerve Recovery and its Effect on Quality of Life following Open Reduction and Internal Fixation of Zygomaticomaxillary Complex Fractures - An Evaluative Study

Introduction

The zygomaticomaxillary complex (ZMC) fractures are the second most common fractures affecting the midfacial skeleton. Neurosensory disturbances of the infraorbital nerve are one of the most common signs of ZMC fractures. The aim of the study was to evaluate the neurosensory recovery of the infraorbital nerve and its effect on the quality of life (QoL) following open reduction and internal fixation of ZMC fractures.

Methods

Thirteen patients clinically and radiologically diagnosed with unilateral ZMC fractures with neurosensory deficits of the infraorbital nerve were enrolled for this study. All patients were assessed presurgically for neurosensory deficits of the infraorbital nerve using the various neurosensory tests, followed by open reduction with two-point fixation under general anaesthesia. The patients were followed up at one, three and six months postoperatively to evaluate the recovery of neurosensory deficits.

Results

Recovery of tactile and pain sensation was relatively complete in 84.62% and 76.92% of patients respectively by the end of six months postoperatively. The spatial mechanoreception of the affected side improved significantly. 61.54% of patients led an excellent QoL six months postoperatively.

Discussion

The majority of the patients with ZMC fractures and neurosensory deficits of the infraorbital nerve, when treated with open reduction and internal fixation, have complete recovery of the neurosensory deficits by the end of six months postoperatively. However, some patients may continue to experience some long-term residual deficits, which can affect the patient's QoL.

Incidence, Aetiology, and Associated Fracture Patterns of Infraorbital Nerve Injuries Following Zygomaticomaxillary Complex Fractures: A Retrospective Analysis of 272 Patients

STUDY DESIGN

Retrospective study.

OBJECTIVE

Zygomaticomaxillary complex (ZMC) fractures are common facial injuries with heterogeneity regarding aetiologies, fracture types, infraorbital nerve (ION) involvement, and treatment methods. The aim of this study was to identify associations between aetiologies, fracture types, and neurological complications. Additionally, treatment methods and recovery time were investigated.

METHODS

Medical files of 272 patients with unilateral and bilateral ZMC fractures were reviewed, whose cases were managed from January 2014 to January 2019 at the Department of Oral and Maxillofacial Surgery, University hospitals Leuven, Belgium. History of ION sensory dysfunction and facial nerve motoric dysfunction were noted during follow-up.

RESULTS

ION hypoaesthesia incidence was 37.3%, with the main causes being fall accidents, road traffic accidents, and interpersonal violence. Significant predictors of ION hypoaesthesia were Zingg type B fractures (P = 0.003), fracture line course through the infraorbital canal (P < .001), orbital floor fracture (P < 0.001), and ZMC dislocation or mobility (P = 0.001).

CONCLUSION

Of all ZMC fractures, 37.3% exhibited ION hypoaesthesia. Only ZMC Zingg type B fractures (74.0%) were significantly more associated with ION hypoaesthesia. ION hypoesthesia was more likely (OR = 2.707) when the fracture line course ran through the infraorbital canal, and was less dependent on the degree of displacement. Neuropathic pain symptoms developed after ZMC fractures in 2.2% patients, posing a treatment challenge. Neuropathic pain symptoms were slightly more common among women, and were associated only with type B or C fractures. No other parameters were found to predict the outcome of this post-traumatic neuropathic pain condition.

Implications of an Anatomical Variation of the Infraorbital Nerve in Orbital Floor Reconstruction

ABSTRACT

Fractures involving the orbital floor such as blow-out fractures may cause damage to the infraorbital nerve (ION). The integrity and course of the nerve should be evaluated preoperatively in order to prevent from such nerve injuries. The anatomy of the ION can show variations in significant number of patients, which should be taken into account in treatment planning. In this report, the authors present a patient with an isolated fracture of the orbital floor, who had abnormal anatomy of his both IONs. Our treatment approach for this patient is presented along with relevant literature findings.

Neuropathic orofacial pain: Characterization of different patient groups using the ICOP first edition, in a tertiary level Orofacial Pain Clinic

OBJECTIVE

To characterize patients with chronic neuropathic orofacial pain in accordance with the International Classification of Orofacial Pain (ICOP first edition) criteria.

STUDY DESIGN

A retrospective chart review of 108 patients was conducted. The most common categories observed were trigeminal neuralgia (TN) (25.9%), burning mouth syndrome (BMS) (11.1%), persistent idiopathic facial pain (PIFP) (26.9%), and posttraumatic trigeminal neuropathic pain (PTTNP) (26.9%); 9.3% of patients could not be categorized.

RESULTS

TN and BMS was more prevalent in the sixth decade, and PIFP and PTTN were more prevalent in the fifth decade. All categories showed female predilection. The pain in TN was predominantly episodic, described as "sharp shooting" and like an "electric shock," unilateral and affecting the V2 division, and with trigger zones in 50% of patients. Pain in BMS was predominantly constant and described as "burning," with the tongue being the most common site. Pain in PIFP and PTTNP was as follows: varied from constant to episodic; described as "burning," "sharp shooting," "throbbing," or "dull aching"; intraoral or extraoral; and mostly involving the V2 or V3 division.

CONCLUSION

This study is the first to characterize patients with neuropathic orofacial pain using the new ICOP criteria. PIFP and PTTNP were most commonly misdiagnosed categories. Using diagnostic criteria will increase the understanding of this patient group.

The effect of delayed photobiomodulation on neurosensory disturbance recovery after zygomatic trauma: A parallel controlled clinical trial

INTRODUCTION

Zygomatic fractures are usually accompanied with neural complications, which are routinely treated by surgery or medication. However, photobiomodulation has been proven as a non-invasive method with better results in nerve's regeneration and repair. Therefore, in this study, we aimed to investigate the healing effect of photobiomodulation on neurosensory defect after facial trauma.

PATIENTS AND METHODS

In this parallel controlled clinical trial, 35 control cases and 36 patients with zygomaticomaxillary complex (ZMC) fractures as well as the sustained infraorbital nerve paresthesia were included. Afterward, Laser irradiation was applied using a GaAlAs diode laser (810 nm, 27 J/cm², 200 mW) on 12 points on malar area of paresthesia during 12 sessions within six weeks. Neurosensory evaluations were performed in four sessions as follows: at baseline, the end of treatment, one month, and three months after the last session of irradiation, which were achieved through three tests including visual analogue scales (VAS) for general sensitivity, two-point discrimination, and pain discrimination. Repeated measure ANOVA, independent t-test, and Chi-square test were used for comparing time trends, each time point, and gender, respectively. P-values less than 0.05 were considered to be statistically significant.

RESULTS

The patients and controls were matched in both terms of age and gender. Baseline results showed non-significant differences between the two groups based on the VAS, pain, and two-point discrimination. Moreover, for VAS scale, some significant differences were observed between the groups by passing "one month and three months from therapy". Pain and two-point discriminations showed a significant difference between the intervention and control groups in "one month after therapy" and "at the end of the therapy, one month after therapy, and three months after therapy", respectively.

CONCLUSION

Photobiomodulation could be considered as an effective treatment option for post-traumatic neurosensory disturbance of facial area in terms of VAS, pain and two-point discrimination, even if not performed early after trauma.

Post-traumatic cephalalgia

After traumatic brain injury (TBI), a host of symptoms of varying severity and associated functional impairment may occur. One of the most commonly encountered and challenging to treat are the post-traumatic cephalalgias. Post-traumatic cephalalgia (PTC) or headache is often conceptualized as a single entity as currently classified using the ICHD-3. Yet, the terminology applicable to the major primary, non-traumatic, headache disorders such as migraine, tension headache, and cervicogenic headache are often used to specify the specific type of headache the patients experiences seemingly disparate from the unitary definition of post-traumatic headache adopted by ICHD-3. More complex post-traumatic presentations attributable to brain injury as well as other headache conditions are important to consider as well as other causes such as medication overuse headache and medication induced headache. Treatment of any post-traumatic cephalalgia must be optimized by understanding that there may be more than one headache pain generator, that comorbid traumatic problems may contribute to the pain presentation and that pre-existing conditions could impact both symptom complaint, clinical presentation and recovery. Any treatment for PTC must harmonize with ongoing medical and psychosocial aspects of recovery.

Does initial reduction at infra-orbital rim first improve malar height and vertical dystopia in ZMC fractures?

PURPOSE

To estimate the clinical and functional results of patients who underwent distinctive types of open reduction and internal fixation of ZMC fractures, with particular emphasis on malar height and vertical dystopia.

MATERIALS AND METHODS

A randomized clinical trial was conducted from August 2016 to October 2019 in which 40 adult patients with ZMC fractures of maxillofacial region were included. Patients were randomly allocated to group A (n = 20; frontozygomatic (F-Z) first 3-point reduction and fixation) or group B (n = 20; group B infra-orbital first 3-point reduction and fixation). All patients were evaluated objectively for malar height and vertical dystopia pre- and post-operatively at 3 months. The data were scrutinized by applying mean and standard deviation and unpaired t test.

RESULTS

Mean values of the malar height and vertical dystopia were statistically significant (P < .05) for group B compared with group A at all intervals. Data analyzed for other secondary variables showed a statistically non-significant difference between the groups (P > 0.05).

CONCLUSION

The results showed improvement in the malar height and vertical dystopia for infra-orbital first three-point fixation (group B) compared with F-Z first approach for initial reduction and fixation (group A). Furthermore, group B was better in terms of malar width and antero-posterior projection of the zygomaticomaxillary complex.

Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation

PURPOSE

Zygomatic bone has a higher risk of sustaining injuries in the maxillofacial skeleton. On fracturing, zygomatic bone separates from the four neighbouring bones at its articulations. Treatment for zygomaticomaxillary fractures has evolved a long way since 3000 BC. With the advent of miniplates for midface fracture, controversies still exist regarding the stability of zygoma following 1, 2, and 3 points for fixation. The study aims to compare and determine the most effective technique for the reduction of zygomaticomaxillary fractures and the ability to retain the fractured zygoma in a stable position. Hence, a study was conducted in our institute to compare 2 and 3-point fixation of zygomaticomaxillary fractures taking into account the clinical and radiographic parameters.

METHODS

Twenty-four patients were divided into 2 equal groups A and B, receiving 2- and 3-point fixation respectively. Fracture displacement and stability were assessed using coronal and axial CT scan tracings at preoperatively, immediate, and 5-week postoperatively.

RESULTS

Group B showed a significant reduction in postoperative mean displacement at sphenozygomatic and infraorbital region when compared with group A. Patients in group A had an increase incidence in vertical dystopia and enophthalmos. There was no postoperative displacement at any site in both the groups.

CONCLUSION

The fractured segment was held in place by both the fixation methods but 3-point fixation gave better stability in maintaining the fractured segment in desired reduced position.

Does the Lag Time Between Injury and Treatment Affect Recovery of Infraorbital Nerve Disturbances in Zygomaticomaxillary Complex Fractures?

Study Design

A cross-sectional study.

Objective

Neurosensory disturbances (NSDs) of the infraorbital nerve (ION) are common following orbito-zygomaticomaxillary complex (ZMC) fractures. This study aimed to evaluate the effect of lag time between injury and treatment on recovery of NSDs of the ION following open reduction internal fixation.

Methods

Subjects who had ZMC fracture and paresthesia were studied. The lag time between injury and treatment was considered as the predictive factor. The level of NSDs according to the brush test and two-point discrimination (TPD) test and self-reported NSD were the outcomes of this study. Self-reported NSD was quantified using a visual analog scale.

Results

Forty patients were studied. The lag time between injury and treatment had a significant correlation with the result of the TPD test and the self-reported level of NSD. In 73.6% of patients who had NSD following ZMC fracture, every 1-day delay in treatment increased the incidence of self-reported paresthesia by 0.44.

Conclusions

It seems, a delay in treatment of ZMC fractures increased the risk of NSD.

Molecular mechanisms of painful traumatic trigeminal neuropathy-Evidence from animal research and clinical correlates

Painful traumatic trigeminal neuropathy (PTTN) may occur following major craniofacial or oral trauma, or may be subsequent to relatively minor dental interventions. Following injury, pain may originate from a peripheral nerve, a ganglion, or from the central nervous system. In this review, we focus on molecular mechanisms of pain resulting from injury to the peripheral branch of the trigeminal nerve. This syndrome has been termed painful traumatic trigeminal neuropathy (PTTN) by the International Headache Society and replaces previous terms including atypical odontalgia, deafferentation pain, traumatic neuropathy and phantom toothache. We emphasize the scientific evidence supporting the events purported to lead to PTTN by reviewing the pathophysiology of PTTN based on relevant animal models. Additionally, we briefly overview clinical correlates and pathophysiological manifestations of PTTN.

Differential gene expression changes in the dorsal root versus trigeminal ganglia following peripheral nerve injury in rats

BACKGROUND

The dorsal root (DRG) and trigeminal (TG) ganglia contain cell bodies of sensory neurons of spinal and trigeminal systems, respectively. They are homologs of each other; however, differences in how the two systems respond to injury exist. Trigeminal nerve injuries rarely result in chronic neuropathic pain (NP). To date, no genes involved in the differential response to nerve injury between the two systems have been identified. We examined transcriptional changes involved in the development of trigeminal and spinal NP.

METHODS

Trigeminal and spinal mononueropathies were induced by chronic constriction injury to the infraorbital or sciatic nerve. Expression levels of 84 genes in the TG and DRG at 4, 8 and 21 days post-injury were measured using real-time PCR.

RESULTS

We found time-dependent and ganglion-specific transcriptional regulation that may contribute to the development of corresponding neuropathies. Among genes significantly regulated in both ganglia Cnr2, Grm5, Htr1a, Il10, Oprd1, Pdyn, Prok2 and Tacr1 were up-regulated in the TG but down-regulated in the DRG at 4 days post-injury; at 21 days post-injury, Adora1, Cd200, Comt, Maob, Mapk3, P2rx4, Ptger1, Tnf and Slc6a2 were significantly up-regulated in the TG but down-regulated in the DRG.

CONCLUSIONS

Our findings suggest that spinal and trigeminal neuropathies due to trauma are differentially regulated. Subtle but important differences between the two ganglia may affect NP development.

SIGNIFICANCE

We present distinct transcriptional alterations in the TG and DRG that may contribute to differences observed in the corresponding mononeuropathies. Since the trigeminal system seems more resistant to developing NP following trauma our findings lay ground for future research to detect genes and pathways that may act in a protective or facilitatory manner. These may be novel and important therapeutic targets.

Acute and chronic pain in orofacial trauma patients

Trauma or injury to the dentition and supporting tissues is associated with pain and discomfort, as expected, that may present immediately, shortly afterwards, or within a few days. Pain is an essential response to injury because it allows the organism to develop avoidance behavior to potential threats and helps the organism to avoid usage of the injured organ during the healing process. Not only does external trauma induce pain, but also essential invasive dental procedures such as extractions, dental implant insertions, root canal treatments, and oral surgeries are accompanied by similar post-surgical (post-traumatic) pain. The pain intensity after trauma varies and does not always correlate with the extent of injury. Trauma to the orofacial region or the teeth may also indirectly affect and induce pain in other orofacial structures such as the masticatory muscles, the temporomandibular joint, and even the cervical spine. In most cases, the pain will resolve as soon as healing of the affected tissue occurs or after dental and routine palliative treatment. In a limited number of cases, the pain persists beyond healing and evolves into a chronic pain state. Chronic pain in the orofacial region presents diagnostic and management challenges. Misdiagnosis or delayed diagnosis of the oral chronic pain condition may lead to unnecessary dental treatment. This article will discuss diagnosis and treatment for acute and chronic pain as well as potential mechanisms involved in the undesirable transition from acute to chronic pain.

Introduction of pulsed radiofrequency cautery in infraorbital nerve block method for postoperative pain management of trauma-induced zygomaticomaxillary complex fracture reduction

Although various cases of neuralgia and its treatments have been reported, not enough evidence is present to recommend a single type of treatment as the most effective. The patient we have dealt with experienced significant interferences in his daily life due to chronic allodynia, but the symptom could not be resolved via previously reported treatments. We report a case of which a patient who presented infraorbital neuralgia after trauma was successfully treated by a novel treatment strategy. The patient was treated by applying infraorbital nerve block and pulsed radiofrequency cautery side by side. Through this report, we evaluate proper prevention and treatment strategies for patients who develop infraorbital neuralgia through similar etiologies.

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A Rare Complication of Infraorbital Nerve Hyperesthesia in Surgically Repaired Orbital Fracture Patients

Injury to the peripheral sensory branches of the trigeminal nerve can follow a wide variety of craniofacial injuries. Many patients with facial fractures complain about the symptom of numbness to the distribution of injured nerve, which is indicative of hypoesthesia. Hyperesthesia involving the infraorbital nerve is rare in comparison to hypoesthesia secondary to facial trauma. The authors report on 2 patients with infraorbital nerve hyperesthesia in surgically repaired orbital fracture patients. Surgical decompression of the infraorbital nerve led to rapid resolution of hyperesthesia. To the best of our knowledge, these were rare cases of patients who presented with persistent hyperesthesia. Clinician should perform early surgical decompression of the infraorbital nerve in patient with persistent hyperesthesia of the infraorbital nerve.

Differential gene expression in trigeminal ganglia of male and female rats following chronic constriction of the infraorbital nerve

BACKGROUND

The mechanisms underlying sex-based differences in pain and analgesia are poorly understood. In this study, we investigated gene expression changes in trigeminal ganglia (TG) of male and female rats exposed to infraorbital nerve chronic constriction injury (IoN-CCI).

METHODS

Somatosensory assessments were performed prior to IoN-CCI and at selected time points postsurgery. Selected gene expression changes were examined with real-time quantitative polymerase chain reaction (RT-PCR) in ipsilateral TG at 21 days postsurgery.

RESULTS

Rats exposed to IoN-CCI developed significant mechanical allodynia and hyperalgesia on days 19 and 21 postsurgery. During this period, females developed significantly more allodynia but not hyperalgesia compared to males. At 21 days postsurgery, expression levels of 44 of the 84 investigated pain-related genes in ipsilateral TG were significantly regulated relative to naïve rats in either sex. Csf1 and Cx3cr1 were up-regulated in both sexes, but the magnitude of regulation was significantly higher in females (p = 0.02 and p = 0.001, respectively). Htr1a and Scn9a were down-regulated in both sexes, but the down-regulation was significantly more pronounced in males (p = 0.04 and p = 0.02, respectively). Additionally, Cck, Il1a, Pla2g1b and Tnf genes were significantly regulated in females but not in males, and Chrna4 gene was significantly down-regulated in males but not in females.

CONCLUSIONS

Our findings suggest sex-dependent gene regulation in response to nerve injury, which may contribute to sex dimorphism of trigeminal neuropathic pain. Further studies are needed to establish gene expression changes over time and correlate these with hormonal and other physiological parameters in male and female.

SIGNIFICANCE

We present novel sex-specific transcriptional regulation in trigeminal ganglia that may contribute to male-/female-based differences in trigeminal neuropathic pain. These findings are expected to open new research horizons, particularly in male versus female targeted therapeutic regimens.

Identifying criteria for diagnosis of post-traumatic pain and altered sensation of the maxillary and mandibular branches of the trigeminal nerve: a systematic review

OBJECTIVE

The aim of the study was to systematically identify criteria used to diagnose patients with trigeminal nerve injury.

STUDY DESIGN

A systematic review of the literature registered in the PROSPERO database. Inclusion criteria were patients diagnosed with nerve injury of the sensory divisions of the maxillary or mandibular branches of the trigeminal nerve, with reported tests and criteria used for diagnosis and persistent pain or unpleasant sensation associated with nerve injury.

RESULTS

In total, 28 articles were included. Diagnostic tests included clinical neurosensory tests (89%), thermal quantitative sensory testing (QST; 25%), electromyography (7%), and patient interview (14%). Neuropathic pain was assessed by using the visual analogue scale (39%); patient use of neuropathic medication (7%); questionnaires, including McGill and PainDETECT (21%). Functional impact was assessed in 14% and psychological impact in 7% of articles. Methodology in performing clinical neurosensory tests, application of diagnostic terms and diagnostic grading of nerve injury was found to be inconsistent among the included articles, making direct comparison of results difficult.

CONCLUSIONS

Recommendations for assessment and diagnosis of trigeminal nerve injury have been made based on the best available evidence from the review. There is an urgent requirement for a consensus in diagnostic criteria, criteria for assessment, and outcome reporting among stakeholder organizations to improve knowledge in this field.

Persistent idiopathic facial pain

Background

Persistent idiopathic facial pain (PIFP) is a chronic disorder recurring daily for more than two hours per day over more than three months, in the absence of clinical neurological deficit. PIFP is the current terminology for Atypical Facial Pain and is characterized by daily or near daily pain that is initially confined but may subsequently spread. Pain cannot be attributed to any pathological process, although traumatic neuropathic mechanisms are suspected. When present intraorally, PIFP has been termed ‘Atypical Odontalgia’, and this entity is discussed in a separate article in this special issue. PIFP is often a difficult but important differential diagnosis among chronic facial pain syndromes.

Aim

To summarize current knowledge on diagnostic criteria, differential diagnosis, pathophysiology and management of PIFP.

Methods

We present a narrative review reporting current literature and personal experience. Additionally, we discuss and differentiate the common differential diagnoses associated with PIFP including traumatic trigeminal neuropathies, regional myofascial pain, atypical neurovascular pains and atypical trigeminal neuropathic pains.

Results and conclusion

The underlying pathophysiology in PIFP is still enigmatic, however neuropathic mechanisms may be relevant. PIFP needs interdisciplinary collaboration to rule out and manage secondary causes, psychiatric comorbidities and other facial pain syndromes, particularly trigeminal neuralgia. Burden of disease and psychiatric comorbidity screening is recommended at an early stage of disease, and should be addressed in the management plan. Future research is needed to establish clear diagnostic criteria and treatment strategies based on clinical findings and individual pathophysiology.

Neuropathic orofacial pain: Facts and fiction

Definition and taxonomy This review deals with neuropathic pain of traumatic origin affecting the trigeminal nerve, i.e. painful post-traumatic trigeminal neuropathy (PTTN). Symptomatology The clinical characteristics of PTTN vary considerably, partly due to the type and extent of injury. Symptoms involve combinations of spontaneous and evoked pain and of positive and negative somatosensory signs. These patients are at risk of going through unnecessary dental/surgical procedures in the attempt to eradicate the cause of the pain, due to the fact that most dentists only rarely encounter PTTN. Epidemiology Overall, approximately 3% of patients with trigeminal nerve injuries develop PTTN. Patients are most often female above the age of 45 years, and both physical and psychological comorbidities are common. Pathophysiology PTTN shares many pathophysiological mechanisms with other peripheral neuropathic pain conditions. Diagnostic considerations PTTN may be confused with one of the regional neuralgias or other orofacial pain conditions. For intraoral PTTN, early stages are often misdiagnosed as odontogenic pain. Pain management Management of PTTN generally follows recommendations for peripheral neuropathic pain. Expert opinion International consensus on classification and taxonomy is urgently needed in order to advance the field related to this condition.

[Zygomaticomaxillary complex fractures with infraorbital nerve damage]

Zygomaticomaxillary complex (ZMC) fracture is a common type of maxillofacial fracture. In addition to facial depression and diplopia, paresthesia of the lower eyelid, malar regions, nose skin, upper lip skin, and mucous membranes occurs because of infraorbital nerve injury. This article reviewed the anatomy, diagnosis, assessment, treatment, and prognosis of ZMC fracture-related infraorbital nerve injury.

Long-term sensory disturbances after orbitozygomatic fractures

BACKGROUND

Orbitozygomatic fractures often lead to infraorbital nerve (ION) injury, and affected sensibility is a common long-term complaint within this patient group. We present a long-term follow-up study where the validated von Frey filament system was used for testing ION sensibility. Furthermore, we examined the incidence of persistent nerve injury and whether more complex fractures led to more pronounced ION sensibility disturbances.

METHODS

Patients treated for facial fractures involving the orbitozygomatic complex were included and the follow-up time was 3 years or more. Depending on the location and severity of the fractures, the patients were divided into 4 groups. The patients answered a questionnaire before ION sensibility testing with von Frey filaments.

RESULTS

Eighty-one patients were examined: 65 males (80%) and 16 females (20%). Examinations were conducted between 3.0 and 7.6 years (mean 4.9 years) after injury. Sixteen patients (20%) had affected and 6 patients (7.4%) had severely affected ION sensibility according to von Frey testing. No statistically significant differences were found in terms of questionnaire score between the groups. There was also no statistically significant correlation between questionnaire results and log von Frey values. Although the effect of groups could not be statistically verified using the log von Frey values, a larger proportion of patients with complex fractures had higher log von Frey values than the other groups.

CONCLUSIONS

Patients with complex fractures report more permanent sensory disturbance of the ION after surgery than those with isolated orbitozygomatic fractures, although this could not be verified statistically with von Frey filament testing at several locations. Hence, a validated method for testing facial sensibility such as von Frey filaments, although sensitive, is inadequate to determine all aspects of sensory malfunction after orbitozygomatic fractures. This suggests that the patient's experience of long-term sensation after trauma may not be correlated with objective measures.

Primary Infraorbital Foramen Decompression for the Zygomaticomaxillary Complex Fracture: Is It Essential?

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.

Continuous neuropathic pain secondary to endoscopic procedures: report of two cases and review of the literature

Neuropathic pain encompasses a spectrum of conditions that can arise from a lesion or dysfunction of the central or the peripheral nervous system, and it may develop at variable intervals after nerve injury or inflammation. Nerve injuries arising from surgical procedures commonly occur secondary to the surgical trauma, and in rare instances they are a complication of intubation during general anesthesia or endoscopic procedures. A series of 2 cases of bilateral glossopharyngeal neuropathic pain subsequent to endoscopic procedures is presented with a review of the literature concerning the mechanisms of development of neuropathic pain after these procedures. The purpose of these case reports is to make dentists aware of the occurrence, the mechanisms of nerve injuries, and the treatment of neuropathic pain after endoscopic procedures. In the first case, the patient had relief of pain with a combination therapy of clonazepam 1.0 mg in divided doses twice daily and gabapentin 300 mg in divided doses 3 times daily. In the second case, the patient had significant relief of pain with a monotherapy of gabapentin 1200 mg in divided doses 3 times daily.

Ocular Injuries in Association with Middle Third Facial Injuries in Developing Countries: A Prospective Study

Introduction

The middle third of the face is the most common site of injury and is frequently complicated by associated ocular injuries. It may be simple laceration, ecchymosis, circumorbital edema, or severe as globe injury or injury to the optic nerve and vision loss. Even severe injury like internal bleeding causes increased intraocular pressure and damages the optic nerve; if managed earlier, it could prevent further damage and dysfunction of the eye. Midfacial fractures associated with ocular injuries should have an early ophthalmological examination to detect ocular injuries. Little is known about the current epidemiology of midface fractures and associated ocular injuries in Tamil Nadu, the state of India. The aim was to study the etiology and pattern of middle third fracture and associated ocular injuries.

Materials and methods

This prospective study on midface fractures was carried out in the Department of Dentistry to analyze etiology, incidence, and patterns of midface fractures and associated ocular injuries. A total of 201 patients who reported with the history of midface injuries were included in the study. These patients were examined clinically and routine radiographs and computerized tomography magnetic resonance imaging (MRI) were taken to confirm the diagnosis. All the patients sustaining confirmed middle third fractures with or without eye signs were referred to an ophthalmology department for the evaluation and management of associated ophthalmic injury. Statistical Package for the Social Sciences software version 16.0 was used for data analysis. The outcome of the study was measured using percentages, mean, standard deviation, and test of proportion as appropriate.

Results

Traffic accident was the major cause of injury, mainly by motorized two wheelers (MTWs). Males in the 21 to 40 age group were common victims. Zygomatic complex fracture was the most common fracture type. Subconjunctival hemorrhage and infraorbital nerve injuries were common clinical findings.

Conclusion

Midthird facial injury cases should have an early ophthalmological examination for timely management to prevent dysfunction of the eye.

How to cite this article

Mohanavalli S, Suma E, Senthamarai G, Vijayabala GS. Ocular Injuries in Association with Middle Third Facial Injuries in Developing Countries: A Prospective Study. World J Dent 2016;7(3):135-140.

Clinical Evaluation of Neurosensory Changes in the Infraorbital Nerve Following Surgical Management of Zygomatico-Maxillary Complex Fractures

INTRODUCTION

Zygomatico-orbital fractures are the second most common facial injuries. Trauma to mid-facial region can lead to an alteration or loss of sensation in the facial region which sometimes requires early surgical intervention to aid in an early recovery.

AIM

To evaluate the different neurosensory changes in the infraorbital nerve function following common treatment modalities used in the management of zygomatico-maxillary complex fractures.

MATERIALS AND METHODS

Thirteen patients selected for the study had unilateral zygomatic complex fracture with altered sensation in the region of distribution of the infraorbital nerve. The fractures were managed either by reduction followed by internal fixation with mini-plates (Group A), reduction alone (Group B) or conservatively (Group C). Infraorbital nerve function tests were done by mechanical, heat and pain threshold detection. Evaluation was done on 1(st), 3(rd), 7(th) day, one month, three months and six months interval in a manner similar to that done at the beginning of the study (Day0).

RESULTS

A male predominance with male:female ratio of 5.5:1 and an age range of 21 to 50 years was found with the right side mostly affected. Road traffic accident was the most common aetiology. Most common clinical presentations were sub-conjunctival haemorrhage (84.61%), flattening of the malar prominence (69.23%) with deficit in neurosensory function of infra orbital nerve. Recovery in the infraorbital nerve function was relatively complete in 76.92% cases with partial recovery in 23.07% of the patients.

CONCLUSION

Marked improvement in the neurosensory function of the infraorbital nerve was found when some form of treatment either in the form of Open Reduction and Internal Fixation (ORIF) or approach through Gillie's temporal or Keen's intraoral approach were applied as compared to when conservative treatment was provided. In zygomatic complex fractures, any form of treatment employed brought about decompression of the infraorbital nerve which aided in the recovery of the nerve within a span of 1-6 months, except when no treatment was applied.

The Sihler staining study of the infraorbital nerve and its clinical complication

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.

Infraorbital nerve posttraumatic deficit and displaced zygomatic fractures: a double-center study

Typical associated signs and symptoms of displaced zygomatic fractures include lack of zygoma projection, diplopia, and sensory disturbances of the infraorbital nerve (ION). The aim of this article was to assess eventual associations between ION sensory disturbances and zygomatic fractures patterns. This study is based on 2 databases that have continuously recorded patients hospitalized with maxillofacial fractures in 2 Departments of Maxillofacial Surgery in Amsterdam, The Netherlands, and Turin, Italy between 2001 and 2010. The following data for patients surgically treated for displaced zygomatic fractures were considered: gender, age, site and severity of facial fractures, etiology, and presenting symptoms. Statistically significant associations were found between ION sensory disturbances and assaults (P = 0.007) and sport accidents (P = 0.00003), as well as between ION sensory disturbances and isolated zygomatic fractures (P = 0.000002) and between ION sensory disturbances and diplopia (P = 0.00009).The severity of injury and the absorption of middle-energy and high-energy forces by the zygomatic complex only were associated with ION sensory disturbances. The etiology and severity of the injury as well as the presence of associated symptoms should be thoroughly investigated when a zygomatic fracture is suspected.

Single buccal sulcus approach with fluoroscan assistance for the management of simple zygomatic fractures

BACKGROUND

Zygomatic fractures are associated with functional and aesthetic problems. The purpose of this study was to evaluate the adequacy of management and the surgical satisfaction of patients with simple zygomatic fractures treated through a single buccal sulcus approach and fluoroscan assistance.

METHODS

Between 2008 and 2012, 42 patients with simple zygomatic fractures were included in the study. The surgical procedure was performed through a single buccal sulcus incision. The fracture sites were aligned under direct vision and fluoroscan assistance and stabilized with rigid internal fixation. The adequacy of reduction was evaluated based on postoperative plain radiographic films and computed tomographic scans using mirror image analyses. The satisfaction of functional and aesthetic results was also evaluated subjectively using a visual analog scale during follow-up.

RESULTS

Twenty-nine male and thirteen female patients with a mean age of 33.2 years were evaluated. Motorcycle crashes (78.6%) were the most common mechanism of trauma. Based on follow-up imaging studies, 2 patients had inadequate reduction of zygomatic body, and there was a slight depression of the zygomatic arch in one patient. Ninety-three percent (39/42) of patients had satisfactory results, although one patient complained of malar asymmetry and another felt a depression in the arch area. Two patients complained of persistent hypesthesia during follow-up at 6 months.

CONCLUSIONS

Our results suggest that a single buccal sulcus approach without lower eyelid or lateral eyebrow incision in the repair of simple fractures of the zygoma can be achieved with high patient satisfaction if the reduction and fixation are adequate and stable.

Orofacial pain syndromes: evaluation and management

Patients will often visit their primary medical practitioner with orofacial pain complaints. Hence, it is important to recognize and have an understanding of these conditions to properly evaluate and potentially manage these disorders. If the practitioner is uncertain or uncomfortable with these conditions, then patient referral to a knowledgeable health care practitioner should be considered for further evaluation and management. In this article, the evaluation and management of various neuropathic, neurovascular, and vascular pains are discussed.

To evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures: A prospective study

Aims:

The present study was undertaken to evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures and to study the morbidity associated with the use of biodegradable plates and screws.

Materials and Methods:

This prospective study consisted of 10 patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection, comminuted and pathological fractures were excluded. All were plated with biodegradable system (Inion CPS) using standard plating principles and observed for a total period of 24 weeks. Characteristics of the fractures, ease of use of bioresorbable plate/screw system and post operative complications were assessed.

Results:

Of total 10 patients, eight patients were of midface fracture and two pediatric patients with mandibular fracture, with nine male and one female. The mean age was 32.8 years. Out of 20 plates and 68 screws applied to the 10 fractures sites; there were three incidences of screw breakage with no other intraoperative difficulties. Paresthesia of the infraorbital nerve was present in two patients, and recovered completely in four weeks after surgery. Fracture reduction was considered to be satisfactory in all cases. One patient developed postsurgical infection and was managed with oral antibiotics and analgesics.

Conclusions:

Favorable healing can be observed through the use of biodegradable plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood, however further studies with more sample size are required.

Pregabalin in post traumatic neuropathic pain: Case studies

Pregabalin is effective in the treatment of peripheral and central neuropathic pain. This study evaluated the effectiveness of pregablin in management of post traumatic peripheral nerve injury facial pain not responding to other medication like analgesics. Pregabalin was well tolerated. The most common adverse effects were dizziness and tiredness.

Endoscopic endonasal approach to the infraorbital nerve with nasolacrimal duct preservation

Objectives Infraorbital nerve (ION) decompression, excision to remove intrinsic tumors, and resection with oncological margins in malignancies with perineural invasion or dissemination are usually accomplished with an open approach. The objective is to describe the surgical anatomy, technique, and indications of the endonasal endoscopic approach (EEA) to the ION with nasolacrimal duct preservation. Design Eleven sides of formalin-fixed specimens were dissected. An anterior maxillary antrostomy was performed. The length of the ION prominence within the sinus and anatomic features of the covering bone were studied. A 45-degree endoscope visualized the infraorbital prominence endonasally. An angled dissector and dural blade allowed for dissection and resection of the ION ipsilaterally and contralaterally. Results The bone features of the ION prominence allowed for ipsilateral dissection in 10 out of 11 sides. In one case with the ION surrounded by thick cortical bone, the dissection could only be started by drilling contralaterally. The 45-degree endoscope visualized 92.2% and 100% of the length of the nerve using the ipsilateral and contralateral nostrils, respectively. Ipsilaterally, 83% of its length was resected, and 96.3% was resected contralaterally. Conclusion The ION can be approached using an ipsilateral EEA with nasolacrimal duct preservation in most cases. The contralateral approach provides a wider angle to access the ION. This technique is primarily indicated in cases where the EEA can be used for tumor resection and oncological margins within the ION.

Management of midface maxillofacial trauma

The management of midface trauma continues to challenge maxillofacial surgeons. The complex local anatomy and functional and cosmetic importance of the region make precise surgical correction and reconstruction essential to success.

Evaluation of Neurosensory Changes in the Infraorbital Nerve following Zygomatic Fractures

PURPOSE

To evaluate the incidence and recovery of persistent sensory disturbances of the infraorbital (IO) nerve after isolated zygomatic complex fractures with various treatment methods.

METHODS AND RESULTS

The study was inclusive of isolated unilateral zygomatic complex fractures and fractures of IO rim .Tests performed were Pin prick and Electrical detection threshold test. The evaluation was done preoperatively, after 1 month and after 6 months of surgery. The results suggested that neurosensory disturbance was present in all the patients with zygomatic complex fractures. At 1 month post-operatively some sensory deficit was present in all the patients on the affected side. After 6 months all the patients showed near to normal improvement comparable to normal side.

CONCLUSION

Study shows that earlier the surgical intervention, more the recovery of the nerve injury is appreciable during the 1 and 6  months follow up period.

The role of sensory input of the chorda tympani nerve and the number of fungiform papillae in burning mouth syndrome

OBJECTIVE

The aim of this study was to evaluate patients suffering from burning mouth syndrome (BMS) and control subjects by means of sensory testing and fungiform papillae count.

STUDY DESIGN

The left and right anterior two-thirds of the tongue of of 25 BMS subjects and 20 healthy control subjects were evaluated for electric taste and electric detection threshold. The number of fungiform papillae/cm(2) was evaluated by using close-up digital photography.

RESULTS

The electric taste/tingling detection threshold ratio was significantly higher in BMS compared with control subjects (P = .041). No difference was found between the number of fungiform papillae/cm(2) in the BMS compared with the control subjects (P = .277). Patients suffering from BMS for a prolonged period of time presented with a significantly elevated electric taste/tingling detection threshold ratio (P = .031).

CONCLUSIONS

BMS may be a neurodegenerative process with chorda tympani nerve hypofunction potentially playing a role in the pathophysiology of this disorder.