Radiological evaluation of inferior alveolar nerve displacement after removal of impacted mandibular third molars prior to sagittal split osteotomy.

INTRODUCTION: We hypothesize that the removal of mandibular third molars (M3) 6 months prior to a bilateral sagittal split osteotomy (BSSO) could allow the displacement of the inferior alveolar nerve (IAN) in a favorable lingual position. This study aimed to radiographically compare the position of IAN before and after M3 removal in patients with Class II malocclusion. MATERIALS AND METHOD: The CBCT images of 30 randomly selected patients (mean age 15.5 years, 19 females and 11 males) were segmented regarding the mandibular bone and the IAN canal. Mandibles were then superimposed and compared using 3D slicer (www.slicer.org). An orthonormal system was constructed, and the coordinates of IAN were assessed in the x- (horizontal axis), y- (depth axis), and z- (vertical axis) directions. RESULTS: The mean changes in x- and z-values were 0.37 %, -0.09 % for the right IAN, 0.07 %, and -0.10 % for the left IAN, respectively. Y-axis was the dimension the most impacted by the M3 removal with a mean variation of -11.96 % for the right IAN, and 0.45 % for the left nerve (p1=0.74 and p2=0.04, respectively). Three patients presented a change in the IAN position superior to 1 mm on at least one coordinate axis. We observed a more important change in x-values of the right IAN in male than in female (p = 0.04), and no significant modifications regarding the other dimensions. Finally, there was no correlation between the age of the patients and the changes in IAN position. CONCLUSION: This study confirms the absence of influence of mandibular third molar removal on the inferior alveolar nerve route prior to BSSO.

Parestesia do nervo alveolar inferior decorrente de procedimentos cirúrgicos e suas formas de tratamentos / Paresthesi of the lower alveolar nerve resulting from surgical procedures and its forms of treatment

Nas cirurgias odontológicas é possível que ocorra alguns acidentes ou complicações que podem interferir no dia a dia do paciente. A lesão do nervo alveolar inferior é uma complicação decorrente de cirurgias orais que podem causar um distúrbio de sensibilidade transitória ou persistente, na região do lábio inferior e na região delimitada do forame mentoniano e hemi-arco da mucosa. O diagnóstico da parestesia pode ser feito através de testes mecanoceptivos e nocioceptivos em que o profissional escolherá para qual melhor se adapte no paciente. O objetivo do presente trabalho foi abordar por meio de uma revisão de literatura as formas de diagnóstico e tratamento da parestesia do nervo alveolar inferior decorrentes de cirurgias orais. As bases de dados utilizadas para confecção desta revisão são encontradas nas bibliotecas virtuais eletrônicas: BVS (Biblioteca Virtual em Saúde), LILACS (Literatura Latino-Americana e do Caribe em Ciências da Saúde) e Pubmed. Como critério de inclusão foram selecionados artigos publicados de 2012 a 2022 em língua inglesa, portuguesa e espanhola. Após a leitura do título e resumo dos resultados da pesquisa e aplicação dos critérios de inclusão e exclusão dentre eles foram excluídos 883, pois não se enquadravam no nosso critério de inclusão. No final, foram selecionados 13 estudos por meio de base de dados, que serviram de base para esta revisão. Concluímos que as formas de tratamento para a parestesia na literatura, são um pouco escassas e conflitantes, mas relata que o uso da laserterapia e acupuntura tem sido uma forma de tratamento com um bom índice de sucesso, e para os casos que não sejam suficientes tais tratamentos, pode-se optar por uma cirurgia(AU)

In dental surgeries it is possible to have some accidents or complications that can interfere with the patient's day. Injury to the inferior alveolar nerve is a complication resulting from oral surgeries that can cause a disturbance of sensitivity that can be transient or persistent in the region of the lower lip and in the delimited region of the mental foramen and hemiarch of the mucosa. The diagnosis of paresthesia can be made through mechanoceptive and nocioceptive tests that the professional will choose, which best suits the patient. The objective of the present work is to approach, through a literature review, the forms of diagnosis and treatment aimed at inferior alveolar nerve paresthesia resulting from oral surgeries. The databases used for this review are found in the virtual electronic libraries: VHL (Virtual Health Library), LILACS (Latin American and Caribbean Literature on Health Sciences) and Pubmed. As inclusion criteria, articles published from 2012 to 2022 in English, Portuguese and Spanish were selected. After reading the title and summary of the research results and applying the inclusion and exclusion criteria, 883 were excluded, as they did not meet our inclusion criteria. In the end, 13 studies were selected from the database, which served as the basis for this review. We conclude that the forms of treatment for paresthesia in the literature are a little scarce and conflicting, but it reports that the use of laser therapy and acupuncture has been a form of treatment with a good success rate, and for cases that are not enough, such treatments, one can opt for surgery(AU)

Characteristics of the ocular surface in neurotrophic keratitis induced by trigeminal nerve injury following neurosurgery.

PURPOSE: To analyse and quantify ocular surface parameters in patients with unilateral neurotrophic keratitis (NK) induced by trigeminal nerve injury post-neurosurgery. METHODS: The study included 26 unilateral NK patients who had undergone neurosurgery, and 20 matched normal controls. Demographic and clinical characteristics of all participants were collected and analysed. Slit-lamp examination, Cochet-Bonnet aesthesiometry, Keratograph 5 M, and LipiView interferometer were performed on both eyes of 17 mild NK patients. For nine moderate/severe NK patients, sub-basal nerve density was measured by in vivo confocal microscopy. RESULTS: Of the 26 patients, nine had acoustic neuroma, nine had trigeminal neuralgia, and eight had neoplasms. Facial nerve paralysis was observed in one of the 17 mild NK eyes (5.9%) and seven of the nine moderate/severe NK eyes (77.8%). Compared to contralateral and normal control eyes, 26 NK eyes showed significantly reduced sensitivity in five corneal regions (P < 0.05). Corneal sensitivity in moderate/severe NK eyes was significantly lower than in mild NK eyes (P < 0.05). Moderate/severe NK eyes had poor visual acuity, and their sub-basal nerve density was lower than that of the controls. The onset of the moderate/severe NK was from 0.5 to 24 months (median [Q1, Q3], 1 [0.5, 2.5] months) after neurosurgery. For the mild NK eyes, the number of total blinks, the first non-invasive tear breakup time (NITBUT) and average NITBUT were significantly lower than contralateral and normal control eyes (P < 0.05), and the number of partial blinks and partial blinking rate were significantly higher than the other two control groups (P < 0.05). CONCLUSIONS: Patients with NK induced by trigeminal nerve injury following neurosurgery had decreased corneal sensitivity to various degrees accompanied by increased partial blinks and shortened NITBUT. The severity of NK is related to the severity of the corneal sensory impairment. Facial nerve paralysis can worsen the clinical progression of NK. Trial registration Chinese Clinical Trial Registry (ChiCTR2100044068, Date of Registration: March 9, 2021).

Predictive scoring model for inferior alveolar nerve injury after lower third molar removal based on features of cone-beam computed tomography image.

INTRODUCTION: This study aimed to construct a predictive scoring system for inferior alveolar nerve injury (IANI) following lower third molar (LM3) surgery based on cone-beam computed tomography (CBCT) images. MATERIAL AND METHODS: Of the 1573 patients who underwent LM3 removal following the CBCT, 39 with IANI and 457 randomly selected patients without IANI were enrolled. We collected information regarding the demographic characteristics of the patients, surgical situations, and inferior alveolar canal (IAC)-related CBCT factors. The association with IANI-risk was evaluated with a backward stepwise logistic regression model as per the Akaike information criterion. Scoring models' abilities of discrimination (area under the curve) and calibration (Hosmer-Lemeshow test and calibration plots) were assessed, followed by evaluation of the clinical usefulness using decision curve analysis. RESULTS: As per the multivariate analysis, the coronal positioned IAC on the enlarged root (odds ratio [OR], 3.78; P = 0.001), the length of perforated IAC (>3.4 mm) (OR, 3.05; P = 0.012), lingual/inter-radicular position of the IAC (OR, 3.96; P = 0.001), multiple roots closed to the perforated IAC (OR, 2.78; P = 0.025), and age >30 y (OR, 2.31; P = 0.076) were identified in the extended scoring model ranging from 0 to 12. This model was compared with our previously constructed baseline model that involved the latter three variables mentioned above, resulting in superior performance than that of the baseline model. CONCLUSION: The extended model would be a useful tool for reliable determination of the preoperative probability of IANI.

Diagnosis and Management of Lingual Nerve Injuries.

Injury to the lingual nerve is a well-recognized risk associated with certain routine dental and oral surgical procedures. The assessment and management of a patient with a traumatic lingual nerve neuropathy requires a logical and stepwise approach. The proper application and interpretation of the various neurosensory tests and maneuvers is critical to establishing an accurate diagnosis. The implementation of a surgical or nonsurgical treatment strategy is based not only on the established diagnosis, but also a multitude of variables including patient age, timing and nature of the injury, and the emotional or psychological impact.

How Many Oral Surgeons Does It Take to Classify a Nerve Injury?

PURPOSE: There is inconsistency in clinical grading of peripheral trigeminal nerve (TN5) injuries that impact patient care. The study goal is to assess the current status of evaluation and classification of TN5 injuries by oral and maxillofacial surgeons (OMSs). PATIENTS AND METHODS: A cross-sectional study design used an electronic survey to 100 selected OMSs to determine their clinical TN5 injury practice, including neurosensory testing, confidence level with current protocols, and evaluation and treatment of a hypothetical TN5 injury case. The target sample was enhanced to reduce type 2 error, assuming prior experience in the diagnosis and management of TN5 injuries. RESULTS: The sample was composed of 90 respondents. Nerve injury classification systems used by OMSs include Seddon (44%), Sunderland (70%), and Medical Research Council Scale (31%). Neurosensory testing protocols varied considerably among survey respondents. A sample case for Medical Research Council Scale grading produced inconsistent and inaccurate results. There was no consensus on TN5 injury management, and recommendations for timely nerve repair varied from 1 month to up to 1 year after injury. Half of the respondents stated that OMSs are not adequately prepared to assess inferior alveolar/lingual nerve injuries, and most oral-maxillofacial surgery respondents evaluate fewer than 10 TN5 injuries each year. Most OMSs (92%) have had a temporary inferior alveolar/lingual nerve injury, while 54% have had a permanent injury; of which, 21% required microsurgical repair. The majority of OMSs (74%) believed that a uniform TN5 injury classification system is needed. CONCLUSIONS: Within the oral-maxillofacial surgery target group experienced in evaluation of TN5 injuries, respondents do not feel confident in the assessment of these injuries. There is inconsistency in evaluation methods, and there is agreement that a unified classification system is needed for more efficient patient evaluation and reporting of outcomes in the literature. The Medical Research Council Scale and clinical neurosensory testing is preferred for evaluation of TN5 injuries.

Trigeminal Neuropathy After Mandibular Fractures: Epidemiology and Neurophysiologic Diagnosis.

OBJECTIVES: To study the trigeminal nerve neuropathy prevalence after mandibular fractures and follow nerve recovery and to examine associations with clinical features. SUBJECTS: The files of 304 patients treated for 424 mandibular fractures in Hadassah Medical Center between 2001 and 2008 were analyzed. Twenty-five patients with paresthesia were examined by electro-diagnostic conduction test (quantitative sensory testing). RESULTS: The most common fracture sites were the symphysis (28.5%) and condyle (21.4%). A strong correlation between fracture severity and treatment modality was found. Nerve damage occurred in 13.4% of nondisplaced fractures and in 65.3% of >5 mm displaced fractures. Patients who were treated by open reduction internal fixation demonstrated the biggest difference in quantitative sensory testing values between the affected and nonaffected sides. C nerve fibers were the most damaged and least regenerated. There was correlation between damage perception and objective test results. CONCLUSIONS: There is a correlation between fracture type and displacement severity on neurologic deficit and prognosis. The objective neurosensory damage was manifested by higher nerve excitation threshold on the injured side. Patients should be informed on the prognosis of neurologic deficit according to fracture type.

Automated detection of third molars and mandibular nerve by deep learning.

The approximity of the inferior alveolar nerve (IAN) to the roots of lower third molars (M3) is a risk factor for the occurrence of nerve damage and subsequent sensory disturbances of the lower lip and chin following the removal of third molars. To assess this risk, the identification of M3 and IAN on dental panoramic radiographs (OPG) is mandatory. In this study, we developed and validated an automated approach, based on deep-learning, to detect and segment the M3 and IAN on OPGs. As a reference, M3s and IAN were segmented manually on 81 OPGs. A deep-learning approach based on U-net was applied on the reference data to train the convolutional neural network (CNN) in the detection and segmentation of the M3 and IAN. Subsequently, the trained U-net was applied onto the original OPGs to detect and segment both structures. Dice-coefficients were calculated to quantify the degree of similarity between the manually and automatically segmented M3s and IAN. The mean dice-coefficients for M3s and IAN were 0.947 ± 0.033 and 0.847 ± 0.099, respectively. Deep-learning is an encouraging approach to segment anatomical structures and later on in clinical decision making, though further enhancement of the algorithm is advised to improve the accuracy.

Subjective perception of paraesthesia of the lower lip after bilateral sagittal split osteotomy at a district general hospital.

Our aim was to assess patients' perception of paraesthesia of the lower lip after bilateral sagittal split osteotomy (BSSO) at a district general hospital. Patients who had BSSO between August 2013 and August 2014 (n=46) were asked to score their perception of numbness between 0-10 (0=normal sensation. 10=complete loss of sensation/total numbness) one day postoperatively and then weekly for seven weeks, and at three months, 6 months, and one year. Data was collected on score sheets and by regular contact by telephone. Of the 46 operated on, 31 were female and 15 male. Data were available one year postoperatively for 43 patients. Ten of the 92 sides were reported as feeling normal on day 1 postoperatively, three-quarters as feeling normal at six months, and 79 at one year. On multivariate analysis there was no significant difference in postoperative sensation at one year between sides operated on by the registrar (left) and consultant (right) operated (p=0.76). Our results compared favourably with the limited data available in similarly designed studies.

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.

Magnetic Resonance Neurography of Traumatic and Nontraumatic Peripheral Trigeminal Neuropathies.

PURPOSE: The clinical neurosensory testing (NST) is currently the reference standard for the diagnosis of traumatic and nontraumatic peripheral trigeminal neuropathies (PTNs), but exhibits both false-positive and false-negative results compared with surgical findings and frequently results in treatment decision delays. We tested the hypothesis that magnetic resonance neurography (MRN) of PTNs can serve as a diagnostic modality by correlating the NST, MRN, and surgical findings. MATERIALS AND METHODS: Sixty patients with traumatic and nontraumatic PTN of varying etiologies and Sunderland classifications underwent NST, followed by MRN using 1.5T and 3.0T scanners. The protocol included 2-dimensional and 3-dimensional (3D) imaging, including diffusion imaging and isotropic 3D PSIF. The MRN findings were read by 2 readers in consensus with the clinical findings but without knowing the side of abnormality. The MRN results were summarized using the Sunderland classification. In 26 patients, surgery was performed, and the Sunderland classification was assigned using the surgical photographs. Agreement between the MRN findings and NST/surgical classification was evaluated using kappa statistics. Pearson's correlation coefficient was used to assess the correlation between continuous measurements of MRN/NST and surgical classification. RESULTS: Of the 60 patients, 19 males and 41 females, mean age 41 years (range 12 to 75), with 54 complaints of altered sensation of the lip, chin, or tongue, including 16 with neuropathic pain and 4 with no neurosensory complaint, were included. Third molar surgery (n = 29) represented the most common cause of traumatic PTN. Assuming 1 nerve abnormality per patient, the lower class was accepted, a kappa of 0.57 was observed between the MRN and NST classification. A kappa of 0.5 was found between MRN and surgical findings with a Pearson correlation coefficient of 0.67. CONCLUSIONS: MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.

Orbital apex syndrome after trauma in a 6-year-old - a rare occurrence.

Orbital apex syndrome is rare, but can occur as a consequence of trauma from fracture of the medial orbit. This case report highlights the fact that a high index of suspicion is needed when a patient presents with a facial injury, especially in children who cannot give an account of the actual events that transpired. Radiological investigation should be done early when an underlying injury is suspected in a trauma patient. A low threshold for computed tomography should be maintained when proptosis and vision loss are present.

Effect of Low-Level Laser and Light-Emitting Diode on Inferior Alveolar Nerve Recovery After Sagittal Split Osteotomy of the Mandible: A Randomized Clinical Trial Study.

PURPOSE: The major concern of sagittal split osteotomy (SSO) is the neurosensory disturbance. The authors investigated the effect of low-level laser therapy and light-emitting diode on the inferior alveolar nerve recovery after SSO. METHODS: In this double-blinded randomized clinical trial, 20 subjects with inferior alveolar nerve injury after SSO of the mandible were studied. Neurosensory recovery was assessed by 6 tests: visual analog scale (VAS), brush stroke, 2-point discrimination, contact detect detection, pinprick nociception, and thermal discrimination, and each one was performed before and after the surgery on days 1, 3, 7, 14, 60, and 180. RESULTS: After 1 week, the VAS score in the laser group significantly improved in comparison with the control group. Visual analog scale score improvement was 25% (P = 0.015) at 2 weeks, 21% (P = 0.001) at 2 months, and 24% (P = 0.001) at 6 months. After 2 weeks, the brush stroke score improvement was significant in the laser group. The improvement values were 21.5% (P = 0.002) at 2 months and 15.1% (P = 0.004) at 6 months. CONCLUSION: Low-level laser therapy and light-emitting diode may improve VAS scores, 2-point discrimination, and brush stroke test results without any effect on the pinprick or contact detection test results.

Thermal Perception as a Key Factor for Assessing Effects of Trigeminal Nerve Injury.

AIMS: To conduct a functional examination using multimodal exploration of a sample of patients with iatrogenic trigeminal nerve injury to understand the underlying mechanisms of neuropathic pain following trigeminal nerve injury. METHODS: Subjective and objective symptoms and responses to thermal and electrical quantitative sensory testing (QST) were evaluated in 85 patients with unilateral trigeminal nerve injury. Objective symptoms were measured by seven clinical sensory tests. Thermal QST included cold detection threshold (CDT), warm detection threshold (WDT), and heat pain threshold (HPT). Electrical current perception threshold was performed with electrical stimuli of 2,000, 250, and 5 Hz. The time since injury was included as a possible independent variable. The data were analyzed using chi-square test, independent t test, Mann Whitney U test, one-way analysis of variance (ANOVA), and Kruskal-Wallis test. Further analyses with Pearson correlation analysis, Spearman rank correlation analysis, and cluster analysis were applied. RESULTS: Unlike objective symptoms, thermal and electrical QST values and subjective symptoms did not improve in patients with an old injury. Thermal QST, particularly WDT, showed the highest positive correlation with subjective symptoms in all tests. Cluster analysis of the thermal QST values identified three subgroups: cluster 1, which was characterized by prominent cold and warm hypoesthesia; cluster 2, which presented elevated WDT; and cluster 3, which showed the smallest thermal differences for all thermal variables but had the highest proportion of neuropathic pain. CONCLUSION: These findings have demonstrated that thermal QST is a suitable tool for evaluating and characterizing the sensory effects of trigeminal nerve injury. Three subgroups with different thermosensory profiles showed that the less the damage, the more neuropathic pain occurs. The loss of warm perception in particular might play a pivotal role in the chronicity and severity of subjective sensory symptoms.

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.

A case series of trigeminal nerve injuries caused by periapical lesions of mandibular teeth.

Aims Periapical lesions have been implicated in mandibular trigeminal sensory neuropathy. This study aimed to report on a case series of consecutive patients presenting with mandibular division trigeminal nerve injuries (TNI) caused by periapical lesions. Common presenting characteristics and possible strategies for management were also investigated.Materials and methods A retrospective study of 22 patients with TNI caused by periapical lesions. Data were extracted from patient records and analysed using Microsoft Excel and SPSS. Factors associated with TNI resolution were assessed using Student's t-Tests and one-way Analysis of Variance (ANOVA), where P <0.05 indicated statistical significance.Results Twenty-one patients had inferior alveolar nerve injuries (IANI) and one had a lingual nerve injury (LNI). The most commonly affected teeth were the first molars (11 patients; 50%). TNI symptoms included numbness, pain and/or paraesthesia. IANI resolved completely among five patients within a mean time of 4.7 months (range 1.5-12 months). Patients who showed complete resolution had the affected teeth extracted or primary endodontic treatment with antibiotics.Conclusions Patients with TNI caused by periapical lesions can suffer significantly from combined numbness, pain and paraesthesia. Resolution of these injuries may be maximised upon early diagnosis and treatment of the periapical lesion by tooth extraction or primary endodontic treatment.

Resolution of neurosensory deficit after mandibular orthognathic surgery: A prospective longitudinal study.

OBJECTIVES: To investigate the longitudinal resolution of neurosensory deficit (NSD) and the possible risk factors that might contribute to NSD following mandibular orthognathic procedures. STUDY DESIGN: A prospective longitudinal observational study on patients who had mandibular orthognathic procedures was performed. Standardized neurosensory assessments were performed. The 2 years longitudinal resolution and risk factors of NSD including patients' age and gender, specific mandibular procedures and surgeons' experience were analyzed. RESULTS: 66 patients (44 females) with 132 sides of mandibular procedures were enrolled in the study. Surgical procedures included mandibular ramus surgery, anterior mandibular surgery, or the combination of the two. The overall occurrences of subjective NSD improved from 78.8% at postoperative 2 weeks to 13.8% at post-operative 2 years. Combinations of ramus surgery and anterior mandibular surgery increased the risk of NSD at the first three post-operative months (p < 0.05). Patients' age and gender, and surgeons' experience were not found to be risk factors of NSD after mandibular orthognathic surgery. CONCLUSION: The occurrence of NSD after mandibular orthognathic procedures reduced progressively within the post-operative 2 years. Combination of mandibular ramus surgery and anterior mandibular surgery increased the risk of NSD in the early post-operative period.