Clinical Neurosensory Testing Research Articles

Efficacy of MR Neurography of Peripheral Trigeminal Nerves: Correlation of Sunderland Grade versus Neurosensory Testing.

The current reference standard of diagnosis for peripheral trigeminal neuropathies (PTN) is clinical neurosensory testing (NST). MR neurography (MRN) is useful for PTN injury diagnosis, but it has only been studied in small case series. The aim of this study was to evaluate the agreement of Sunderland grades of nerve injury on MRN and NST by using surgical findings and final diagnoses as reference standards. A total of 297 patient records with a chief complaint of PTN neuralgia were identified from the university database, and 70 patients with confirmed NST and MRN findings who underwent surgical nerve repair were included in the analysis. Cohen weighted kappa was used to calculate the strength of the agreement between the 3 modalities. There were 19 men and 51 women, with a mean age of 39.6 years and a standard deviation of 16.9 years. Most (51/70, 73%) injuries resulted from tooth extractions and implants. MRN injury grades agreed with surgical findings in 84.09% (37/44) of cases, and NST injury grades agreed with surgical findings in 74.19% (23/31) of cases. MRN and NST both showed similar agreement with surgery for grades I to III (70% and 71.43%). However, MRN showed a higher rate of agreement with surgery (88.24%) for injury grades IV and V than did NST (75%). MRN can objectively improve preoperative planning in patients with higher-grade nerve injuries.

Accuracy of MR neurography as a diagnostic tool in detecting injuries to the lingual and inferior alveolar nerve in patients with iatrogenic post-traumatic trigeminal neuropathy

ObjectivesMR neurography has the ability to detect and depict peripheral nerve injuries. This study evaluated the potential of MR neurography in the diagnosis of post-traumatic trigeminal neuropathy.MethodsForty-one participants prospectively underwent MR neurography of the lingual and inferior alveolar nerves using a 3D TSE STIR black-blood sequence. Two blinded and independent observers recorded the following information for each nerve of interest: presence of injury, nerve thickness, nerve signal intensity, MR neurography Sunderland class, and signal gap. Afterwards, the apparent nerve-muscle contrast-to-noise ratio and apparent signal-to-noise ratio were calculated. Clinical data (neurosensory testing score and clinical Sunderland class) was extracted retrospectively from the medical records of patients diagnosed with post-traumatic trigeminal neuropathy.ResultsCompared to neurosensory testing, MR neurography had a sensitivity of 38.2% and specificity of 93.5% detecting nerve injuries. When differentiated according to clinical Sunderland class, sensitivity was 19.1% in the presence of a low class injury (I to III) and improved to 83.3% in the presence of a high class (IV to V). Specificity remained unchanged. The area under the curve using the apparent nerve-muscle contrast-to-noise ratio, apparent signal-to-noise ratio, and nerve thickness to predict the presence of an injury was 0.78 (p < .05). Signal intensities and nerve diameter increased in injured nerves (p < .05). Clinical and MR neurography Sunderland scores positively correlated (correlation coefficient = 0.53; p = .005).ConclusionsThis study shows that MR neurography can accurately differentiate between injured and healthy nerves, especially in the presence of a more severe nerve injury.Clinical relevance statementMR neurography is not only able to detect trigeminal nerve injuries, but it can also provide information about the anatomical specifications of the injury, which is not possible with clinical neurosensory testing. This makes MR neurography an added value in the management of post-traumatic trigeminal neuropathy.Key Points• The current diagnosis of post-traumatic trigeminal neuropathy is mainly based on clinical examination.• MR neurography is able to visualize and stratify peripheral trigeminal nerve injuries.• MR neurography contributes to the diagnostic process as well as to further decision-making.

Middle superior and anterior superior alveolar nerve injury following trauma to the maxillary sinus: a prospective clinico-radiographic evaluation.

Anterior maxillary sinus wall fractures are common in all types of maxillofacial trauma. They can result in various complications, including injury to the surrounding nerves. Owing to its anatomy, trauma to the maxillary antrum can result in injury to the middle superior alveolar nerve (MSAN) and the anterior superior alveolar nerve (ASAN). The purpose of this study is to evaluate neurosensory deficits (NSD) present in maxillary gingiva, incisors, and premolars after injury to the anterior wall of the maxillary antrum. This prospective study was conducted among 39 patients sustaining unilateral fractures of the anterior maxillary sinus wall. Clinical neurosensory tests including two-point discrimination and fine touch discrimination were performed to classify the extent of nerve injuries as mild, moderate, severe, or anesthetic. Additional temperature discrimination and pulpal sensibility tests (electric pulp testing and cold testing) were carried out. A comparison of radiographic fracture patterns and severity of nerve injury was done. Testing was carried out immediately after trauma and at 2-month follow-up. More than half of the patients assessed in the study group presented with NSD of the teeth and gingiva after trauma. The incidence of deficits varied with the type of test used to measure them. Most frequently, patients presented with both loss of two point as well as fine touch discrimination thresholds. Severe nerve injuries were associated with loss of temperature discrimination clinically and displaced fractures radiographically. There was no significant relationship between the recovery of pulpal and gingival sensation. The patterns of injury and recovery in ASAN and MSAN were similar. NSD after trauma to the maxillary antrum is relatively common. Clinical loss of temperature discrimination and radiographic signs of fracture lines passing through the canalis sinuosus are predictors of persistent and severe oral NSD.

Frequency and Pattern of Presentation of Mental Nerve Injury During Para Symphysis Fracture

Aim: The mandibular fracture at the parasymphysis is the most often seen fracture of a facial bone. The occurrence of anaesthesia or paraesthesia in the skin and mucous membrane within the distribution of the mental nerve may be seen due to mental nerve injury resulting from fractures in the Parasymphysis region. This condition has the potential to impact the overall well-being of affected individuals. Objective: To determine the Frequency and pattern of presentation of mental nerve injury during Para symphysis fracture. Method: The present research is an observational and descriptive investigation including a sample of 65 patients diagnosed with parasymphysis fracture. The study was done at the Nishter Institute of Dentistry in Multan, Pakistan, spanning from September 2021 to February 2023.Following the endorsement of the research by the Ethical Review Board of the hospital, patients were recruited using a non-probability sequential sampling method. The researchers used clinical neuro-sensory testing (NST) as a means of evaluating nerve damage and determining the specific kind of neurosensory impairment that occurred subsequent to a para symphysis fracture. A specifically prepared proforma is used as a tool for data collecting. The data underwent statistical analysis, and findings and observations were derived from the analysis. Results: The study assessed the incidence of mental nerve damage in instances with Para symphysis fracture, revealing that 23 cases (35%) exhibited the presence of mental nerve injury, whereas it was missing in 42 cases (65%). The study observed a total of 23 individuals, consisting of 17 males and 6 females, who were diagnosed with mental nerve damage. The most often encountered neurosensory problems experienced by patients after surgery are paraesthesia. Additionally, it has been shown that the leading cause of parasymphysis fracture in both males and females is road traffic accidents (RTA). Conclusions: Road traffic accidents (RTAs) have been identified as a significant factor contributing to parasymphysis fractures. These fractures may result in the development of neurosensory deficits either as a consequence of the initial trauma or as a complication after surgical intervention. It has been seen that such fractures can lead to persistent complications and a decrease in overall quality of life. Additionally, it is essential to conduct additional research studies that cover a longer duration and include a bigger cohort of patients. Keywords: Mandibular fracture, Mental nerve, Paraesthesia, Trauma

Frequency and Pattern of Presentation of Infra-Orbital Nerve Injury in Patients of Zygomatic Bone Fracture

Aim: In order to evaluate the frequency and kind of infraorbital nerve injury in zygomatic bone fractures Method: A cross-sectional study was conducted from February 2022 to January 2023 at the Oral and Maxillo-Facial Surgery Department, Nishtar Institute of Dentistry, Multan. Sixty-four zygomatic bone fracture patients were included, meeting inclusion and exclusion criteria after a complete clinical and radiological examination. Clinical neuro-sensory testing (NST) was performed to assess nerve injury. The patient's demographic data, cause of fracture, presence, and type of nerve injury were collected on a specially designed proforma. The data was analysed using SPSS version 22. Frequencies, percentages, and mean ± standard deviation were taken. Results: Sixty four patients were included with male into female ratio of 4.34:1. There was male predominance. Most common cause of ION injury, in zygomatic bone fractures was RTA (n=13,46.4%) while nerve injury was present in 29 patients (46.77%) of patients. Most common presentation of ION nerve injury was paresthesia n=10,34.5%. Conclusion: Zygomatic bone fracture is the leading cause of infra-orbital nerve injury and its most common presentation is paresthesia. Keywords: infra-orbital nerve (ION) injury, paresthesia, zygomatic bone (ZMC) fracture

Application of Tinel’s test combed with clinical neurosensory test distinguishes spontaneous healing of lingual nerve neuropathy after mandibular third molar extraction

BackgroundExtraction of the mandibular third molar, the most frequent and important surgical procedure in the clinical practice of oral surgery, is associated with the risk of injury of the lingual nerve. Neuropathy of the lingual nerve poses diagnostic challenges regarding the transient or permanent nature of the injury. No consensus or criteria have been established regarding the diagnosis of lingual nerve neuropathy. We applied both Tinel’s test and clinical neurosensory testing together, which can be easily used at the bedside in the early stages of injury. Therefore, we propose a new method to differentiate between lesions with the ability to heal spontaneously and those that cannot heal without surgery.ResultsThirty-three patients (29 women, 4 men; mean age, 35.5 years) were included in this study. For all patients, the median interval between nerve injury and initial examination was 1.6 months and that between nerve injury and the second examination before determining the need for surgical management was 4.5 months. The patients were assigned to either group A or B. The spontaneous healing group (group A, n = 10) revealed a tendency for recovery within 6 months after tooth extraction. In this group, although there were individual differences in the degree of recovery, a remarkable tendency for recovery was observed based on clinical neurosensory testing in all cases. None of the patients were diagnosed with allodynia. In seven cases, the Tinel test result was negative at the first inspection, and in three cases, the result changed to negative at the second inspection. Conversely, in group B(n = 23), no recovery trend was observed with regard to clinical neurosensory testing, and nine patients had allodynia. Further, the Tinel test result was positive for all patients in both examinations.ConclusionsOur findings indicate that in case of transient lingual nerve paralysis, clinical neurosensory testing findings deteriorate immediately after tooth extraction and gradually recover, while Tinel’s test shows a negative result. Using Tinel’s test and clinical neurosensory testing together enabled early and easy identification of the severity of the lingual nerve disorder and of lesions that would heal spontaneously without surgical management.

Infralingular Versus Supralingular Medial Osteotomy in Sagittal Split Osteotomy of the Mandible: A Randomized Control Study

A recently proposed modification of the sagittal split osteotomy (SSO) of the mandible places the horizontal medial cut 'low and short' of the lingula. The purpose of the study was to answer the following clinical question: Among patients undergoing mandibular setback procedures (≤ 8mm) via SSO, does the placement of the medial horizontal osteotomy below the lingula (infralingular), when compared to placement above the lingula (supralingular), results in different neurosensory, bite force, and range of motion outcomes? This was a single-center, double-blind, parallel-group study among patients undergoing mandibular setback by SSO (≤ 8mm), between January 2021 and September 2022. Patients were randomly allocated in a ratio of 1:1 to the supralingular (control) and the infralingular (study) group. Primary outcome variables included neurosensory disturbance of the inferior alveolar nerve based on clinical neurosensory testing and severity graded using Zuniga and Essick's protocol, bite force, and maximum mouth opening evaluated postoperatively during the first week (T1), first month (T2), and third month (T3) of follow-up. Secondary outcome measures included the incidence of a bad split and distal segment interferences intraoperatively. Association between the variables was assessed using Pearson chi-squared test or Fisher's exact test based on the expected observations. A P value of ≤.05 was considered statistically significant. A total of 29 patients (58 osteotomies) were included in the study. Group 1 consisted of 15 patients (9 females and 6 males) with a mean age of 26.4years. Group 2 consisted of 14 patients (8 females and 6 males) with a mean age of 25.9years. Patients with severe neurosensory disturbance of the inferior alveolar nerve were more common in group 2 (n=15, 53.6%) than group 1 (n=4, 13.3%) at T1 (P value=.0001) and insignificant between the two groups at T2 (P value=.63) and T3 (P value=.99). Comparison of maximum mouth opening between the two groups at T1 (P value=.535), T2 (P value=.934), and T3 (P value=.703) and bite force at T1 (P=.324), T2 (P=.113), and T3 (P=.811) was not significant. Both SSO techniques have similar clinical outcomes among patients having mandibular setbacks (≤ 8mm) for the variables studied.

Comparison of Early Post-Operative Hypoesthesia After a Low and Short or Traditional Sagittal Split Osteotomy

<h3>Purpose</h3> The purpose of this study was to determine if there is a difference in postoperative neurosensory testing (NST) score at 6-weeks between subjects that received a mandibular sagittal split osteotomy (SSO) using a low and short osteotomy (LSO) or traditional osteotomy (TRO). The null hypothesis was that no significant difference exists in post-operative NST score between subjects that received SSO with a TRO or LSO. <h3>Methods</h3> A retrospective chart review was conducted of subjects that received orthognathic surgery by the oral and maxillofacial surgery department at the University of Texas Southwestern Medical Center (UTSW) from 2017 to 2019. All subjects that received SSO by either TRO as defined by Hunsuck and Epker(1,2) or LSO defined by Posnick(3) were included. Subjects with syndromic conditions, prior injury to the inferior alveolar nerve, history of peripheral neuropathy or pain conditions, and those undergoing simultaneous genioplasty, repeat surgery or concomitant temporomandibular joint surgery were excluded. Neurosensory outcomes of the inferior alveolar nerve (IAN) were measured using clinical NST at the pre-operative and 6-week post-operative visit over a 1-centimeter area of the labiomental fold. Chi-squared analysis and t-tests were performed between the cohorts and their respective outcomes. Values of p < 0.05 were considered statistically significant. The primary predictor variable was osteotomy type, and the primary outcome variable was NST score at the 6 weeks post-operative visit. Secondary outcome variable was IAN location within the proximal or distal segment. <h3>Results</h3> A total of 26 subjects met the defined inclusion criteria for a total of 52 osteotomies. There were 32 osteotomies in the LSO group, and 20 in the TRO group. The average age of the LSO group was 23.1 years (SD=10), and the average age of the TRO group was 22.4 years (SD=6). There was no significant difference in age between the two groups (p=0.84). All subjects were NST level A pass bilaterally at the pre-operative visit. No nerve injury was witnessed at the time of surgery among either group. All IANs contained within the proximal segments were left in place. There was no statistically significant difference in NST score between the two groups at the 6-week post-operative visit (p = 0.40). Of the total 52 osteotomies, there was no significant difference between NST score at the 6 weeks post-operative visit in subjects with IAN located in the proximal segment or the distal segment regardless of technique used (p = 0.52). <h3>Conclusion</h3> There is no difference in post-operative NST score at 6-weeks between subjects that received a traditional osteotomy or low and short sagittal split osteotomy. Regardless of technique, there is no difference in post-operative NST score at 6 weeks if the IAN is in the proximal or distal segment after completion of sagittal split.

Effectiveness and Distribution of Anesthesia for a Modified Extra Oral Maxillo-Mandibular Nerve Block for Dento-Alveolar Procedures: A Prospective Cohort Study.

To evaluate the effectiveness of a modified maxillo-mandibular nerve block technique that includes anesthetizing the maxillary and mandibular nerve with single injection. A prospective, clinical cohort study was carried out including patients who presented for surgical removal of maxillary and mandibular third molars. All patients were administered maxilla-mandibular nerve block through a single injection on one side. Three clinical neurosensory tests were used for mapping the area of anesthesia and to assess and grade objectively the effect of the block. Light touch (LT), two-point discrimination (TPD), pin prick (PP) and Electric pulp testing (EPT) were used for all branches of maxillary and mandibular nerve. An extra oral mapping chart for depth of anesthesia was maintained for each patient to categorize the grades as nil, intermediate and highly anesthetized areas. 62 patients were assessed in the study. EPT showed greater depth of pulpal anesthesia in posterior teeth than the anterior in both maxilla and mandible. PP and TPD tests also showed that the anesthetic effect varied between posterior divisions demonstrating extreme anesthesia compared to the anterior divisions. This technique was found to be successful for surgical extractions involving the maxillary and mandibular regions. The online version contains supplementary material available at 10.1007/s12663-022-01755-w.

Inferior alveolar nerve dysfunction in mandibular fractures: a prospective cohort study.

ObjectivesTo assess the prevalence and recovery of inferior alveolar nerve dysfunction (IAND) in mandibular fractures.Materials and MethodsThis was a prospective cohort study. Clinical neurosensory testing was done preoperatively and the IAND was categorized as mild, moderate or severe. Postoperatively, neurosensory testing was repeated at 1 day, 1 week, 1 month, 3 months and every 3 months thereafter.ResultsA total of 257 patients with 420 fractures were included in the study with a mean age of 31.7 years. Body fractures (95.9%) had the highest incidence of IAND, followed by the angle fractures (90.1%) and symphysis fractures (27.6%). The condyle and coronoid fractures did not have any IAND and hence were excluded from further study. After eliminating those cases, 232 patients remained in the study with 293 fractures. The overall prevalence of IAND in fractures occurring distal to the mandibular foramen was 56.3%. The changes until 1 week were minimal. From 1 month to 6 months, there was a significant reduction in the severity of IAND. A significant number of cases (60.0%) were lost to follow-up between 6 and 9 months. At 6 months, 23.9% of cases still had some form of IAND and 95.0% of the symphysis, 59.0% of the angle and 34.8% of the body fractures with IAND had become normal.ConclusionThis study documents the reduction in the degree of severity of IAND in the first six months and provides the basis for future studies with longer periods of follow-up.

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

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). 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. 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 1month to up to 1year 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. 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.

Immediate Reconstruction of the Infraorbital Nerve After Maxillectomy: Is it Feasible?

Ablative procedures of the midface may require sacrifice of the infraorbital nerve (ION) resulting in permanent paresthesia of its dermatome. Because the ION is not commonly reconstructed, the goal of this study was to determine the feasibility of nerve allograft reconstruction. A retrospective cohort of patients underwent immediate ION allograft reconstruction, during August 2018 to August 2019 at a single academic medical center by a single surgeon (M.M.). Demographic and clinical variables were collected. The outcome of interest was clinical neurosensory testing using the Medical Research Council Scale and subjective recovery, which was recorded using a visual analog scale at 3, 6, and 12months after surgery. This cohort series consisted of 3 consecutive patients who underwent immediate ION allograft reconstruction. At 6months, all patients achieved functional sensory recovery (S3, S3+, and S4) and acceptable subjective improvement. Immediate nerve allograft reconstruction of the ION is a viable option to achieve functional sensory recovery.

A systematic review on diagnostic test accuracy of magnetic resonance neurography versus clinical neurosensory assessment for post-traumatic trigeminal neuropathy in patients reporting neurosensory disturbance.

Objectives:To perform a systematic review of published studies on diagnostic accuracy of magnetic resonance neurography (MRN) vs clinical neurosensory testing (NST) for post-traumatic trigeminal neuropathy (PTTN) in patients reporting neurosensory disturbances (NSD).Methods:Human studies except case reports, reviews, systematic reviews and meta-analyses were included. PubMed, Embase, Web of Science and Cochrane Library were consulted. Risk of bias assessment was conducted using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Predetermined data extraction parameters were noted and summarized.Results:8 studies met eligibility criteria of which 7 were retrospective, representing 444 subjects. Most studies were at high risk of bias with low applicability concerns. Populations and objectives were divergent with a large variation in timing (3 days–17 years post injury) and parameters (multiple coil designs, fat suppression techniques, additional contrast agent) of MRI acquisition. T2 weighted 3 T imaging with short echo times (2.2–100 ms) and fat suppression was applied in seven studies, techniques varied. Determination of sensitivity and specificity could not be performed due to the methodological variation between studies and lacking comparative data between index and reference tests. Based on limited data, PTTN correlated reasonably well between clinical assessment, intraoperative findings and MRN abnormalities (k = 0.57). Increased signal intensity correlated with persistency of neurosensory disturbances in one study. Intra- (ICC 0.914–0.927) and interobserver (k = 0.70–0.891) MRN variability was considered good to excellent. One retrospective study showed substantial impact of MRN on clinical decision making in one-third of patients.Conclusion:Currently, there is insufficient scientific knowledge to support or refute the use of MRN. Based on limited data, MRN seems promising and reliable in detection and grading of PTTN. Methodological issues underline the importance for prospective blinded studies with standardization of signal intensity calculation and rigorous reporting of MRI acquisition parameters.

Photobiomodulation therapy for management of inferior alveolar nerve injury post-extraction of impacted lower third molars.

Inferior alveolar nerve (IAN) injury is one of the most serious complications after extraction of impacted lower third molars. Photobiomodulation (PBM) therapy has been noted to reduce pain and inflammation while promoting tissue healing. This study examined the efficacy of PBM therapy tested in a case series of patients with postoperative IAN injury. 20 patients with post-extraction IAN injury were involved in this study and divided into two groups. In the study group, PBM therapy (808-nm laser, 16 mW, 3 J/cm2) was used every other day for 2 weeks solely on post-extraction sockets in 10 patients diagnosed with IAN injury. In the control group, mecobalamine was prescribed to 10 patients with IAN injury. Objective and subjective recovery of IAN paresthesia was evaluated using clinical neurosensory testing and visual analog score. All patients showed improvement in both objective and subjective examination. Notably, the visual analog score was significantly improved after PBM treatment compared to the mecobalamine treatment (p < 0.05). PBM therapy with 808-nm laser appears to be an effective approach to manage paresthesia post-IAN injury following impacted third molar surgery. Given the limited sample size in this study, large-scale, placebo-controlled, multi-center randomized controlled trials are needed for further validation of this innovative treatment.

Does Piezosurgery Influence the Severity of Neurosensory Disturbance Following Bilateral Sagittal Split Osteotomy?

The present paper aims to evaluate the long-term incidence and severity of the neurosensory disturbance (NSD) of the inferior alveolar nerve following bilateral sagittal split osteotomy (BSSO) of the mandibular ramus performed with piezosurgery. A retrospective study on patients referred to the Maxillofacial Surgery and Dentistry Clinic of the University of Verona for orthognathic surgery between March 2013 and October 2015 was performed. Inclusion criteria were having undergone BSSO with piezosurgery and follow-up lasting at least 24 months. Exclusion criteria were history of surgical infection, osteosynthesis failure or re-do surgery. The extent of mandibular repositioning movements was retrieved and patients underwent 4 clinical neurosensory tests. Descriptive statistical analysis was performed. 52 patients met the inclusion criteria. Average follow-up was 40 months (range 24-75). 83% of the nerves examined have no or slightly altered sensitivity. Seventy-one percent of patients perceive a moderate to none discomfort and none describes the discomfort as serious (Visual Analogue Scale [VAS] >7). The extent of mandibular repositioning did not have significant influence on the development and severity of the NSD. Resulting data led the Authors to infer that using piezosurgery in BSSO, the severity of the NSD of inferior alveolar nerve is reduced, but the incidence of permanent nerve lesions remains unchanged, compared to historical controls.

Risk factors for hypesthesia after repair of facial fractures

The aim of this study was to investigate the incidence of hypesthesia in patients with facial bone fractures and to identify the relationships between posttraumatic hypesthesia and risk factors, including general and fracture-related characteristics. A total of 437 patients who underwent surgery for facial bone fractures were included. Clinical neurosensory testing was performed at different time points (immediately after trauma and 1 week, 1 month, and 6 months after surgery). The results of these assessments were compared with regard to characteristics and fracture sites. The hypesthesia incidences were highest in the mandible (19.1%), maxilla (18.3%), and orbit (8.5%). Sensation was recovered by 97.3% of all patients by 6 months after surgery. Risk factors for hypesthesia were direct nerve injury (P = .002), distance (≤10 mm) between the fracture and nerve foramen (P = .002), the amount of bony displacement (P = .035), and age (P = .004). There were significant differences among the fracture sites. Posttraumatic hypesthesia increased temporarily after surgery, but most patients recovered by 6 months postoperatively. Recovery from postoperative hypesthesia was related to the fracture site and pattern. Cases in which the patient did not recover involved direct nerve injury.

Does Low-Level Laser Therapy Affect Recovery of Lingual and Inferior Alveolar Nerve Injuries?

Iatrogenic damage to the inferior alveolar nerve (IAN) and lingual nerve (LN) may occur during routine oral and maxillofacial surgery procedures. The primary aim of this study was to determine, using a prospective, double-blind, randomized controlled clinical trial, whether the proportion of nerve-injured patients with postoperative neurosensory improvement over a 3-month period differed significantly between a control group and a low-level laser therapy (LLLT) group. The study sample consisted of 35 patients with iatrogenic nerve injury due to third molar odontectomy, dental implant placement, or local anesthetic injection. The investigators used a randomized, double-blind laser delivery system to administer either placebo or LLLT to patients who met the inclusion criteria. The outcome variable of neurosensory improvement was defined as a minimum 1-unit increase from baseline in visual analog scale rating and was based on standard objective clinical neurosensory testing. Study variables included the affected nerve (IAN or LN) and time from injury to treatment (3 to 12months or >12months). Univariate statistical analysis (χ2 test) was performed to determine significance between the groups. Neurosensory improvement was observed in 46.7% of the LLLT patients, who showed at least a 1-unit improvement at 3months, compared with 38.5% improvement for controls (P=.66), regardless of the specific nerve involved (IAN or LN). In addition, no observed difference was noted between the study groups based on time from injury to treatment. This study failed to provide sufficient evidence to conclude that a difference in neurosensory improvement exists between the LLLT and placebo groups with IAN or LN injuries. However, this study is unique in the prospective double-blind study design and comprehensive neurosensory testing protocols. There is a continued need for further clinical studies on LLLT in oral and maxillofacial surgery nerve injuries.

Magnetic Resonance Neurography of Traumatic and Nontraumatic Peripheral Trigeminal Neuropathies

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. 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. Of the 60 patients, 19 males and 41 females, mean age 41years (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. MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.

Role of MR Neurography for the Diagnosis of Peripheral Trigeminal Nerve Injuries in Patients with Prior Molar Tooth Extraction.

Clinical neurosensory testing is an imperfect reference standard to evaluate molar tooth extraction related peripheral trigeminal neuropathy. The purpose was to evaluate the diagnostic accuracy of MR neurography in this domain and correlation with neurosensory testing and surgery. In this retrospective study, nerve caliber, T2 signal intensity ratio, and contrast-to-noise ratios were recorded by 2 observers using MR neurography for bilateral branches of the peripheral trigeminal nerve, the inferior alveolar and lingual nerves. Patient demographics and correlation of the MR neurography findings with the Sunderland classification of nerve injury and intraoperative findings of surgical patients were obtained. Among 42 patients, the mean ± SD age for case and control patients were 35.8 ± 10.2 years and 43.2 ± 11.5 years, respectively, with male-to-female ratios of 1:1.4 and 1:5, respectively. Case subjects (peripheral trigeminal neuropathy or injury) had significantly larger differences in nerve thickness, T2 signal intensity ratio, and contrast-to-noise ratios than control patients for the inferior alveolar nerve and lingual nerve (P = .01 and .0001, .012 and .005, and .01 and .01, respectively). Receiver operating characteristic analysis showed a significant association among differences in nerve thickness, T2 signal intensity ratio, and contrast-to-noise ratios and nerve injury (area under the curve, 0.83-0.84 for the inferior alveolar nerve and 0.77-0.78 for the lingual nerve). Interobserver agreement was good for the inferior alveolar nerve (intraclass correlation coefficient, 0.70-0.79) and good to excellent for the lingual nerve (intraclass correlation coefficient, 0.75-0.85). MR neurography correlations with respect to clinical neurosensory testing and surgical classifications were moderate to good. Pearson correlation coefficients of 0.68 and 0.81 and κ of 0.60 and 0.77 were observed for differences in nerve thickness. MR neurography can be reliably used for the diagnosis of injuries to the peripheral trigeminal nerve related to molar tooth extractions, with good to excellent correlation of imaging with clinical findings and surgical results.

Classification of Post-Traumatic Trigeminal Nerve Injuries Comparing MR Neurography with Clinical Neurosensory Tests and Surgical Findings

Classification of Post-Traumatic Trigeminal Nerve Injuries Comparing MR Neurography with Clinical Neurosensory Tests and Surgical Findings