Iatrogenic trigeminal post-traumatic neuropathy: a retrospective two-year cohort study

Permanent lingual nerve injury after dental procedures: a retrospective study of 228 patients

Lingual nerve injury (LNI) is a rare, serious complication and previous studies include limited numbers of cases. The aim of this retrospective study was to report the neurosensory outcomes for a large patient cohort with permanent LNI and correlate the mechanism of injury (surgical vs non-surgical) to neurosensory characteristics. Demographics, procedural parameters, mandibular third molar (M3) position, surgeon type, neurosensory test results, and symptoms were recorded for 228 patients and analysed. The majority were female (67.1%). Overall, 59.6% of LNIs were caused by M3 removal and 36.4% by local anaesthesia. Complete loss occurred more frequently in surgical LNIs (P = 0.013). The presence of pain did not differ significantly, however the burning type of pain was significantly more frequent in non-surgical LNIs (P = 0.008) along with altered gustation (P = 0.025). The most common M3 position related to LNI was distoangular (40.4%), class III (63.2%), level A (58.1%) (Winter/Pell and Gregory classifications). The majority of patients undergoing M3 removal were >24 years. A total of 71.7% showed no sign of recovery and 5.5% reported further impairment in their condition. Overall, nine patients underwent microsurgical repair. This study presents neurosensory characteristics potentially decisive for timely referral of operable LNIs.

Post-Traumatic Trigeminal Neuropathic Pain: A Narrative Review of Understanding, Management, and Prognosis

This study provides an updated overview of the clinical characteristics of post-traumatic trigeminal neuropathic pain (PTNP) resulting from dental procedures or facial trauma, addressing its etiology, prevalence, evaluation, management, and prognosis. PTNP arises from injury to the trigeminal nerve, which governs sensory and motor functions in the maxillofacial region. The prevalence and characteristics of PTNP vary considerably across studies, with a reported prevalence ranging from 1.55% to 13%. The predominant causative factors are dental procedures, particularly third molar removal and implant placement. While gender distribution varies, a trend towards higher incidence in females is observed, particularly within the 40-60-year age group. Anatomically, the mandibular nerve is frequently involved. PTNP presents with a spectrum of symptoms ranging from tingling sensations to severe pain. Diagnostic challenges arise due to the lack of standardized criteria and potential overlap with focal neuralgia, necessitating comprehensive evaluation. Misdiagnosis can lead to prolonged patient suffering and unnecessary interventions. Successful management hinges on prompt diagnosis and interdisciplinary collaboration, with early intervention crucial in mitigating progression to chronic pain. Although nerve recovery post-trauma is challenging, preventive measures through accurate evaluation and treatment are paramount. Management strategies for PTNP include non-invasive and surgical interventions, with non-invasive approaches encompassing systemic and local pharmacological management. This narrative review aims to enhance uniformity in PTNP evaluation and treatment approaches, ultimately improving patient care and outcomes.

Inferior alveolar nerve injury resulting from different implant rotary instruments: An ex vivo comparative study in human cadaveric mandibles

The present study aimed to evaluate the degree of nerve injury on inferior alveolar nerve (IAN) by different implant drills resulting from direct canal intrusion into inferior alveolar canal (IAC). A cadaveric study involving 7 human mandibles was performed to evaluate mechanical injury of canal enclosed IAN resulting from different drills. In group 1, osteotomies were created using different drills with 1 mm of intracanal intrusion, simulating accidental drill intrusion into canal. In group 2, drilling was stopped when the tip has breached into IAC, limited by tactile feedback of operator. The depth and width of nerve defects were assessed using optical coherence tomography. A significant difference in defect depth was found (p < 0.001) in group 1. A sinus lift reamer inflicted the least damage (0.068 ± 0.022 mm). It was also found that the mean defect depth was significantly different when a twist drill was used (p = 0.016). Sinus lift reamer can be used safely for osteotomy preparation in mandible when bone height is limited or when radiographic visualization of canal is poor. Bone corticalization around IAC does not provide adequate protection for IAN in the event of accidental intracanal intrusion.

Trigeminal nerve injuries following dental procedures: A retrospective analysis of malpractice claims from 2016 to 2023 in South Korea

BACKGROUND

Dental malpractice claims, which pertain to legal actions against dentists accused of clinical negligence that caused harm to patients, have increased in the past ten years in South Korea. The claims are caused by complications, particularly trigeminal nerve injuries, resulting from various dental procedures. Medicolegal issues related to trigeminal nerve injury have not been previously described in South Korea. Therefore, in this study, we aimed to identify the general, dental, and judicial characteristics of closed dental malpractice claims.

METHODS

This study was designed as a descriptive study. We collected the data of 51 closed claims related to trigeminal nerve injury resulting from dental procedures such as dental implant emplacement, tooth extraction, and local anesthesia. The claims were decided by courts in South Korea between 2016 and 2023. The general, dental, and judicial characteristics of the claims were analyzed retrospectively.

RESULTS

The average claim resolution period was 4.2 (range: 1.47-8.39) years post-adverse events that occurred more frequently in dental clinics (68.6 %) than in dental (25.5 %) or general hospitals (5.9 %). Inferior alveolar (66.7 %) and lingual (17.6 %) nerves were injured following dental procedures. The duty to inform was breached in 68.6 % of claims. The dental procedure performed (P < 0.001) and the injured nerve (P < 0.001) were associated with the violation of the duty to care.

CONCLUSION

To improve the quality of dental care services, the analysis of the adverse events using various resources including judgments should be strongly addressed.

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

OBJECTIVES

MR 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.

METHODS

Forty-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.

RESULTS

Compared 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).

CONCLUSIONS

This 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 STATEMENT

MR 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.

Clinical insights into traumatic injury of the inferior alveolar and lingual nerves: a comprehensive approach from diagnosis to therapeutic interventions

OBJECTIVES

This scoping review explores the risk and management of traumatic injuries to the inferior alveolar and lingual nerves during mandibular dental procedures. Emphasizing the significance of diagnostic tools, the review amalgamates existing knowledge to offer a comprehensive overview.

MATERIALS AND METHODS

A literature search across PubMed, Embase, and Cochrane Library informed the analysis.

RESULTS

Traumatic injuries often lead to hypo-/anesthesia and neuropathic pain, impacting individuals psychologically and socially. Diagnosis involves thorough anamnesis, clinical-neurological evaluations, and radiographic imaging. Severity varies, allowing for conservative or surgical interventions. Immediate action is recommended for reversible causes, while surgical therapies like decompression, readaptation, or reconstruction yield favorable outcomes. Conservative management, utilizing topical anesthesia, capsaicin, and systemic medications (tricyclic antidepressants, antipsychotics, and serotonin-norepinephrine-reuptake-inhibitors), proves effective for neuropathic pain.

CONCLUSIONS

Traumatic nerve injuries, though common in dental surgery, often go unrecorded. Despite lacking a definitive diagnostic gold standard, a meticulous examination of the injury and subsequent impairments is crucial.

CLINICAL RELEVANCE

Tailoring treatment to each case's characteristics is essential, recognizing the absence of a universal solution. This approach aims to optimize outcomes, restore functionality, and improve the quality of life for affected individuals.

Consensus guidelines on training, diagnosis, treatment and follow-up care of trigeminal nerve injuries

The aim was to present expert-based guidelines on the management of trigeminal nerve injuries. A two-round multidisciplinary Delphi study was conducted amongst international trigeminal nerve injury experts with a set of statements and three summary flowcharts using a nine-point Likert scale (1 = strongly disagree; 9 = strongly agree). An item was deemed appropriate if the median panel score was within the range of 7-9, undecided if the score was 4-6, and inappropriate if the score was 1-3. Consensus was achieved if at least 75% of panelists scored within one range. Eighteen specialists from dental, medical, and surgical specialties participated in both rounds. Consensus was reached on most statements related to training/services (78%) and diagnosis (80%). Statements related to treatment were mainly undecided due to a lack of sufficient evidence for some of the proposed treatments. Nevertheless, the summary treatment flowchart reached consensus with a median score of eight. Recommendations on follow-up and opportunities for future research were discussed. None of the statements were deemed inappropriate. A set of recommendations and accepted flowcharts are presented; these will aid professionals involved in managing patients with trigeminal nerve injuries.

The effect of individual drilling sleeves on the precision of coronectomy tooth sections. An in vitro 3D-printed jaw model experiment

OBJECTIVES

The aim of this in vitro study was to evaluate the effect of a 3D-printed drill sleeve (DS) on the precision and duration of coronectomy sections.

MATERIALS AND METHODS

Thirty-six trainees and oral surgeons performed 72 coronectomy cuts in a 3D-printed, entirely symmetric mandible model. Coronectomy was performed freehand (FH) on one side and with a DS on the other side. The occurrence of "too superficial" (≥ 4 mm unprepared lingual tooth tissue) and "too deep" (drilling ≥ 1 mm deeper as tooth contour) cuts and sectioning times were registered.

RESULTS

In 7 cases, the sections were "too deep" with FH, while none with DS (OR: 18.56; 95%CI: 1.02-338.5; p = 0.048). The deviation between virtually planned and real cut depths was significantly greater in the FH group (1.91 ± 1.62 mm) than in DS group (1.21 ± 0.72 mm) (p < 0.001). A total of 18 "too superficial" buccolingual sections occurred with FH, while 8 cases with DS (OR: 3.50; 95%CI: 1.26-9.72; p = 0.016). Suboptimal sections did not correlate with experience (p = 0.983; p = 0.697). Shortest, suboptimal drillings were most frequently seen distolingually (OR: 6.76; 95% CI: 1.57-29.07; p = 0.01). In the inexperienced group, sectioning time was significantly longer with FH (158.95 ± 125.61 s vs. 106.92 ± 100.79 s; p = 0.038).

CONCLUSIONS

The DS effectively reduced tooth sectioning times by less experienced colleagues. Independently from the level of experience, the use of DS obviated the need for any preparation outside the lingual tooth contour and significantly decreased the occurrence of "too superficial" cuts, leaving thinner unprepared residual tooth tissue lingually.

CLINICAL RELEVANCE

Coronectomy sections may result in lingual hard and soft tissue injury with the possibility of damaging the lingual nerve. The precision of the buccolingual depth-control can be improved, while surgical time can be reduced when applying a drilling sleeve.

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.

Misleading information before lower third molar surgery - 40 years of failing our patients?

Lower third molar removal is a common surgical procedure that, like all surgery, carries with it inherent risks. One primary risk of significance is inferior dental nerve injury, which can have a significant impact on patients' lives. Conventional consenting usually involves the generic discussion of risks of inferior dental nerve injury but without any substantive personalised risk assessment. Following the Montgomery judgement, these warnings have to be considered both inadequate and potentially misleading, as they are based on population research that is inherently flawed; pre-surgical risk assessments should be focused on the individual. This paper will consider the inadequacy of current consenting protocols and will suggest how we might offer clearer guidance to our patients when seeking valid consent for third molar surgery.

Healthcare costs of post-traumatic trigeminal neuropathy in Belgium - A retrospective analysis

The present aim was to estimate direct health care costs of patients suffering from post-traumatic trigeminal neuropathy (PTTN) and to compare the use of health care services, medications, and costs between temporary and persistent (>3 months) PTTN cohorts. A pre-existing clinical dataset of PTTN patients visiting a tertiary orofacial pain clinic in Belgium was utilized, including symptoms and quality of life measurements. Cost and resource utilization data were obtained by Belgium's largest health insurance provider for a period of 5 years after onset. Data from 158 patients was analyzed. The average cost per patient in the first year after injury was €2353 (IQR 1426-4499) with an out-of-pocket expense of 25% of the total cost. Hospitalization and technical interventions were the main drivers of cumulative costs, followed by consultation costs. For each cost category, expenditure was significantly higher in patients with persistent PTTN than in those with temporary PTTN (median 5-year total costs in persistent PTTN patients yielded €8866 (IQR 4368-18191) versus €4432 (IQR 2156-9032) in temporary PTTN, p <0.001) PTTN patients received repeated and frequent head and neck imaging (mean number of imaging investigations per patient was 10 ± 12). Medication consumption was high, with an unwarranted higher use of opioids and antibiotics in persistent PTTN patients. Within the limitations of this study, it seems there is a need for informing patients in detail on the inherent risks of nerve damage during dental and oromaxillofacial procedures. Every surgery should be preceded by a risk-benefit assessment in order to avoid unnecessary nerve damage.

Prognostic factors, symptom evolution, and quality of life of posttraumatic trigeminal neuropathy

ABSTRACT

Neurosensory disturbances (NSDs) caused by injury to the trigeminal nerve can affect many aspects of daily life. However, factors affecting the persistence of NSDs in patients with posttraumatic trigeminal neuropathies (PTTNs) remain largely unknown. The identification of such risk factors will allow for the phenotyping of patients with PTTNs, which is crucial for improving treatment strategies. We therefore aimed to identify the prognostic factors of NSD persistence, pain intensity, and quality of life (QoL) in patients with PTTNs and to use these factors to create a prognostic prediction model. We first performed a bivariate analysis using retrospective longitudinal data from 384 patients with NSDs related to posttraumatic injury of the trigeminal nerve (mean follow-up time: 322 ± 302 weeks). Bivariate and multivariate analyses were performed. The multivariable prediction model to predict persistent NSDs was able to identify 76.9% of patients with persistent NSDs, with an excellent level of discrimination (area under the receiver operating characteristic curve: 0.84; sensitivity: 81.8%; specificity: 70.0%). Furthermore, neurosensory recovery was significantly associated with sex; injury caused by local anesthesia, extraction, third molar surgery, or endodontic treatment; and the presence of thermal hyperesthesia. Pain intensity and QoL analysis revealed several factors associated with higher pain levels and poorer QoL. Together, our findings may aid in predicting patient prognosis after dental, oral, and maxillofacial surgery and might lead to personalized treatment options and improved patient outcomes.

Iatrogenic Glossopharyngeal Neuropathy in Aesthetic Practice: A Case Report

Iatrogenic glossopharyngeal nerve injuries are commonly associated with procedures such as a tonsillectomy, carotid endarterectomy, and endotracheal intubation. We present a previously unreported complication of a thread lift procedure in the jowl region, causing damage to the glossopharyngeal nerve through compression. The glossopharyngeal nerve belongs to the bulbar group of the cranial nerves. It is connected with the vagus and, therefore, is closely associated with the latter functionally and anatomically. Damage to the former may present with cardiovascular complications associated with the vagus nerve. The presented case demonstrates the diagnostic and treatment aspects of iatrogenic injury to the glossopharyngeal nerve.

Exploring the roles of neuropeptides in trigeminal neuropathic pain: A systematic review and narrative synthesis of animal studies

OBJECTIVE

This systematic review aims to explore the changes in expression of neuropeptides and/or their receptors following experimental trigeminal neuropathic pain in animals.

DESIGN

MEDLINE, Embase, and Scopus were searched for publications up to 31st March 2021. Study selection and data extraction were completed by two independent reviewers based on the eligibility criteria. The quality of articles was judged based on the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk-of-bias tool.

RESULTS

A total of 19 studies satisfied the eligibility criteria and were included for narrative synthesis. Methods of trigeminal neuropathic pain induction were nerve ligation, nerve compression/crush, nerve transection and dental pulp injury. Animal behaviours used for pain verification were evoked responses to mechanical and thermal stimuli. Non-evoked behaviours, including vertical exploration, grooming and food consumption, were also employed in some studies. Calcitonin gene-related peptide (CGRP) and substance P were the most frequently reported neuropeptides. Overall, unclear to high risk of bias was identified in the included studies.

CONCLUSIONS

Limited evidence has suggested the pro-nociceptive role of CGRP in trigeminal neuropathic pain. In order to further translational pain research, animal models of trigeminal neuropathic pain and pain validation methods need to be optimised. Complete reporting of future studies based on available guidelines to improve confidence in research is encouraged.

Variant Innervation of the Medial Pterygoid Muscle from the Lingual Nerve

During a routine dissection of the infratemporal fossa and lateral face, a branch of the left lingual nerve was observed entering the medial pterygoid muscle. Normally, the nerve to the medial pterygoid is a direct branch from the mandibular nerve, with no communications with the lingual nerve. There are many reports involving variations of the mandibular nerve; however, few reports describe lingual nerve variations involving the medial pterygoid muscle. Reconstructive surgeries for cosmesis and trauma, tumor excision, and impacted third molar removal may all damage the lingual nerve and might, as seen in the present case, affect the medial pterygoid muscle. Given the presumed rarity of this variation, we discuss the possible embryological origins as well as the surgical conflicts that may arise with this type of variation.

Do anatomical variations of the mandibular canal pose an increased risk of inferior alveolar nerve injury after third molar removal?

OBJECTIVES

The present study aimed to assess whether anatomical variations of the mandibular canal are associated with neurosensory disturbances of the inferior alveolar nerve (IAN) following mandibular third molar removal.

METHODS

Two observers compared the detection of third molar root-nerve relations and bifurcations of the mandibular canal on panoramic radiographs and CBCT images of 201 patients undergoing removal of 357 mandibular third molars. Potential neurosensory disturbances of the IAN were surveyed ten days after surgery. Fisher's Exact was performed to correlate presence of canal variations to postoperative neurosensory disturbances. Positive and negative predictive values (PPV, NPV) and likelihood ratios (LR + , LR-) were calculated.

RESULTS

Thirteen patients reported postoperative altered sensation of the lower lip, with 2 of them having mandibular canal bifurcations on the ipsilateral side of the injury. Fisher's Exact showed that the studied mandibular canal variations were not related to postoperative neurosensory disturbances. CBCT was superior in visualization of anatomical variations of the mandibular canal. Prevalence of bifurcations was 14% on CBCT and 7% on panoramic radiographs. In both imaging modalities and for all parameters, PPVs were low (0.04 - 0.06) and NPVs were high (0.92 - 0.98), with LR ranging around 1.

CONCLUSION

In the present study, the assessed mandibular canal variations had limited predictive value for IAN neurosensory disturbances following third molar removal.

CLINICAL RELEVANCE

While a close relation between the third molar and the mandibular canal remains a high risk factor, mandibular canal variations did not pose an increased risk of postoperative IAN injury after third molar removal.

Are women more susceptible than men to iatrogenic inferior alveolar nerve injury in dental implant surgery?

An over-representation of women in dental implant-related inferior alveolar nerve injuries (IANIs) is recognized in the literature but has not been investigated. Therefore, a nationwide retrospective register study was conducted to analyse how IANIs compare with other implant-related complications (infection, implant malposition, lack of bone at implant site, mechanical damage, or failed osseointegration) separately in women and men. Financially compensated malpractice claims related to dental implant surgery were collected from the Finnish Patient Insurance Centre for the years 1997-2013, while the total number of nationally placed implants was ascertained from the implant register held by the Finnish Institute for Health and Welfare. In the 242 complications, the following were analysed: age of subject, absolute risk for complication, and aetiological factor of IANI. Statistical tests applied include Mann-Whitney U-test, Chi-squared test, and Fisher's exact test. Women sustaining IANI were more likely older than those having infection, mechanical damage, or failed osseointegration (P<0.05), while no significant differences emerged in men. Women were more likely at risk for IANI (P<0.01) or implant malposition (P<0.05) than men. The results support earlier propositions that women are more vulnerable than men to iatrogenic IANI.

Post-traumatic trigeminal neuropathy: correlation between objective and subjective assessments and a prediction model for neurosensory recovery

BACKGROUND

Post-traumatic trigeminal neuropathy (PTN) can have a substantial effect on patient well-being. However, the relation between the neuropathic symptoms and their effect on psychosocial functioning remains a matter of debate. The purpose of this study was to evaluate the association between objective and subjective assessments of neurosensory function in PTN and predict neurosensory outcome using baseline measurements.

METHODS

This prospective observational cohort study included patients diagnosed with PTN at the Department of Oral and Maxillofacial Surgery, University Hospital Leuven, Belgium, between April 2018 and May 2020. Standardized objective and subjective neurosensory examinations were recorded simultaneously on multiple occasions during the follow-up period. Correlation analyses and principal component analysis were conducted, and a prediction model of neurosensory recovery was developed.

RESULTS

Quality of life correlated significantly (P < 0.05) with percentage of affected dermatome (ρ = - 0.35), the presence of brush stroke allodynia (ρ = - 0.24), gain-of-function sensory phenotype (ρ = - 0.41), Medical Research Council Scale (ρ = 0.36), and Sunderland classification (ρ = - 0.21). Quality of life was not significantly correlated (P > 0.05) with directional discrimination, stimulus localization, two-point discrimination, or sensory loss-of-function. The prediction model showed a negative predictive value for neurosensory recovery after 6 months of 87%.

CONCLUSIONS

We found a strong correlation of subjective well-being with the presence of brush stroke allodynia, thermal and/or mechanical hyperesthesia, and the size of the neuropathic area. These results suggest that positive symptoms dominate the effect on affect. In patients reporting poor subjective well-being in the absence of positive symptoms or a large neuropathic area, additional attention towards psychosocial triggers might enhance treatment outcome. The prediction model could contribute to establishing realistic expectations about the likelihood of neurosensory recovery but remains to be validated in future studies.

Microsurgical Repair of Inferior Alveolar Nerve Injuries Associated With Endodontic Treatment: Results on Sensory Function and Relief of Pain

PURPOSE

An uncommon, but serious complication of endodontic treatment is inferior alveolar nerve (IAN) injury warranting operative intervention for exploration, debridement, and repair. The purpose of the study was to evaluate outcomes of microneurosurgical intervention for endotontic-related IAN injuries in terms of achievement of functional sensory recovery (FSR) and pain relief and to identify factors affecting outcomes.

METHODS

A retrospective cohort study of patients who had microsurgical exploration and repair of IAN injuries sustained during endodontic therapy was performed. The primary predictor variable is time to surgery and the primary outcome variables were time to FSR, whether or not the patient regained FSR, and postoperative pain level at 12 months (1-10 on a visual analog scale). Secondary variables include intraoperative findings, surgical treatment rendered, sensory recovery, and preoperative pain level. Analyses include Kaplan-Meier estimation, Fisher exact test, 1-way and mixed-design analysis of variance, and paired t-test.

RESULTS

The sample included 23 patients with a mean age of 48.6 years with a female:male ratio of 20:3. Painful sensation was present in 17 (73.9%) of 23 patients at initial consultation. Mean time to surgery was 10.9 months (median 4.8 months, standard deviation = ±16.9). FSR was achieved in 10 of 21 patients at 1 year. Pain level at 1 year following surgical intervention improved from 4.86 to 2.76 (P = .001) with no effect from other variables.

CONCLUSIONS

Surgical exploration and repair of endodontic-related IAN injuries is shown to improve neuropathic pain levels, while only delivering a modest recovery of sensory function. These injuries can be severe and debilitating and present with a variety of diagnoses and surgical findings. While this study fails to identify any particular factors affecting outcome, the data presented can help with clinician recommendations for treatment in patient-centered care.

Is it possible to extract lower third molars with infiltration anaesthesia techniques using articaine? A double-blind randomized clinical trial

OBJECTIVE

To compare the efficacy and safety of inferior alveolar nerve blocks (IANB) with additional buccal infiltration (standard technique) and of buccal and lingual anaesthetic infiltration (experimental technique) for lower third molar (L3M) extractions.

STUDY DESIGN

A randomised, double-blind clinical trial involving 129 L3M extractions was conducted. In the IANB group, an IANB was performed using the conventional approach, followed by a buccal injection in the extraction area. In the infiltration group (INF), an infiltration was performed in the buccal and lingual areas of the lower second molar. A 4% articaine solution was employed in all cases. The main outcome variable was anaesthetic efficacy. Other variables like intraoperative and postoperative pain, onset time and adverse events were also recorded. Descriptive and bivariate analyses of the data were made.

RESULTS

120 patients were randomised. The IANB group showed significantly higher anaesthetic efficacy than the INF group (64.4 vs. 45.8%) (odds ratio = 0.47; 95% confidence interval = 0.22-0.97; p = 0.042). No complications were observed.

CONCLUSIONS

IANB with additional buccal infiltration is more suitable than the experimental technique for achieving adequate analgesia in L3M extractions. Moreover, the standard method is safe and provides a shorter onset time and lower initial postoperative pain levels.

Please spare my teeth! Dental procedures and trigeminal neuralgia

Background:

The correct diagnosis of trigeminal neuralgia (TN) is still a far cry and the patients suffer from unnecessary dental procedures before getting the definite treatment. In this study, we evaluated, if the patients have undergone dental procedures for their misdiagnosed TN before receiving definite treatment for the same.

Methods:

A total of 187 patients received GKRS for their TN (excluding secondary TN) in two institutes from 2010 to 2019. We did a retrospective analysis of these patients’ primary complaints on a standard questionnaire.

Results:

One hundred and seventeen of the 187 patients responded. About 55.5% of patients had a toothache and 65.8% did visit a dentist for the pain. About 41.8% of patients underwent one dental procedure; 18.8% suffered from worsening of the pain while 8.5% received some partial improvement. About 19.6% also underwent root canal treatment while 6.8% had a nerve block. Mean of 1.6 teeth was extracted per person. About 71% of patients were satisfied with their Gamma Knife radiosurgery for TN at a median follow-up of 49 months.

Conclusion:

There is a need for a better understanding of the disease among the dentists and the patients for the timely and correct treatment, without losing their teeth. The onus lies on neurosurgeons/neurologists disseminate knowledge regarding proper diagnosis and treatment modalities.

Treatment of panic disorder by trigeminal nerve manipulation: A case series

This is a report on two cases of patients with acute severe panic disorder relieved of their symptoms by manual manipulations of the trigeminal nerve's alveolar branches. The manipulations were performed via the oral cavity during one session, or two consecutive sessions less than a week apart. No other effective treatment was administered prior, concurrently or since the time of the treatment. The recovery from panic disorder was immediate and lasted for the entire period of observation of three years. The authors used the same procedure and achieved identical clinical results treating ten other clients over a period of three years. This was not a planned experiment or randomized study. Rather, this report presents clinical evidence and the authors' hypothesis based on clinical data and literature review.

Clinical outcomes of lingual nerve repair

Lingual nerve injury, a well-described complication of third molar removal, may result in permanent lingual sensory deficit leading to symptoms including lost or altered sensation, inadvertent tongue biting, and the development of unpleasant neuropathic pain, with consequent impaired quality of life. We analysed outcomes of a prospective case series to determine whether direct anastomosis of the lingual nerve results in improved sensory recovery and reduced neuropathic pain, and whether delayed surgery is worthwhile. In 114 patients who underwent nerve repair at our nerve injury clinic following damage sustained during mandibular third molar removal, sensory deficit was assessed before and after surgery using a questionnaire and visual analogue scales (VAS) to assess pain, tingling, and discomfort. Neurosensory tests were utilised to evaluate light touch, pin-prick, and two-point discrimination thresholds. Subjectively, 94% patients felt their sensation had improved following nerve repair, with significant reductions in the incidence of tongue biting (p<0.0001), impaired speech (p<0.0001), and neuropathic pain (p=0.0017). Quantitative neurosensory data showed highly significant improvements in light touch, pin-prick, and two-point discrimination (all p<0.0001), and VAS scores for pain (p=0.0145), tingling (p<0.0025), and discomfort (p<0.0001) were significantly reduced. Patients with high levels of pain preoperatively (VAS>40) showed highly significant reductions in pain (p<0.0001). No correlation was found between surgical outcome and patient's age or delay until surgery. Lingual nerve repair results in good sensory outcomes and significant improvements in the incidence and degree of neuropathic pain, even when delayed.

Signs and symptoms, quality of life and psychosocial data in 1331 post-traumatic trigeminal neuropathy patients seen in two tertiary referral centres in two countries

Background

Post‐traumatic trigeminal neuropathy (PTN) is a disturbance of function or pathological change of the trigeminal nerve branches following trauma and has an important impact on patient's quality of life (QoL).

Objectives

To provide diagnostic data on PTN and illustrate differences in aetiology, injured nerve, pain distribution, sensory profile and QoL between PTN subgroups.

Methods

1331 patients with painful or non‐painful PTN were retrospectively reviewed in two centres, extracting demographic data, time and cause of trauma, clinical findings including signs and symptoms, basic neurosensory testing, imaging modalities, treatments, and QoL or psychosocial assessment.

Results

More females were represented (70%) than males. The inferior alveolar nerve was most frequently damaged (60%) followed by the lingual nerve (28%). Wisdom teeth removal was considered the main cause (48%). Pain was reported in 63% of patients and pain frequency increased with age without clinically significant gender differences. Numbness was reported in 50% of PTN patients. Neurosensory testing showed larger affected dermatome involvement in persistent injuries, with no differences between the non‐painful and painful PTN groups. Patient clustering indicated different sensory profile distributions when stratified according to aetiology or affected nerve branch. High interference with lifestyle was reported (78%), and patients suffering from painful PTN had worse QoL and psychosocial outcomes.

Conclusion

Patients with painful PTN had different clinical profiles and lower QoL scores than those with non‐painful PTN. Sensory profiles may provide important prognostic and therapeutic information; however, more research is needed to assess the clustering procedure and link these clusters to therapeutic guidelines.

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.

Neuromodulation of the lingual nerve: a novel technique

Acute injury of the trigeminal nerve or its branches can result in posttraumatic trigeminal neuropathy (PTTN). Affected patients suffer from chronic debilitating symptoms long after they have recovered from the inciting trauma. Symptoms vary but usually consist of paresthesia, allodynia, dysesthesia, hyperalgesia, or a combination of these symptoms. PTTN of the trigeminal nerve can result from a variety of traumas, including iatrogenic injury from various dental and maxillofacial procedures. Treatments include medications, pulsed radiofrequency modulation, and microsurgical repair. Although trigeminal nerve stimulation has been reported for trigeminal neuropathy, V3 implantation is often avoided because of an elevated migration risk secondary to mandibular motion, and lingual nerve implantation has not been documented. Here, the authors report on a patient who suffered from refractory PTTN despite multiple alternative treatments. He elected to undergo novel placement of a lingual nerve stimulator for neuromodulation therapy. To the best of the authors' knowledge, this is the first documented case of lingual nerve stimulator implantation for lingual neuropathy, a technique for potentially reducing the risk of electrode migration.

MRI of the inferior alveolar nerve and lingual nerve-anatomical variation and morphometric benchmark values of nerve diameters in healthy subjects

OBJECTIVE

Since MRI using dedicated imaging sequences has recently shown promising results in direct visualization of the inferior alveolar nerve (IAN) and the lingual nerve (LN) with high spatial resolution, the aim of this study was to generate suitable standard specifications to reliably depict the IAN and LN in MRI and to delineate the anatomy and its variants of these nerves in healthy subjects.

METHODS

Thirty healthy volunteers were examined on a 3-T scanner (Elition, Philips Healthcare, Best, the Netherlands). The sequence protocol consisted of 3D STIR, 3D DESS, and 3D T1 FFE "black bone" sequences.

RESULTS

The study reconfirmed a good feasibility of direct visualization of proximal and peripheral portions of the IAN and of the proximal course of the LN. The STIR sequence showed the highest apparent signal to noise ratio (aSNR) and best apparent nerve-muscle contrast to noise ratio (aNMCNR) for IAN and for the LN. The applied MRI sequences allowed to differentiate the tissue composition of the neurovascular bundle inside the mandibular canal.

CONCLUSION

Dedicated MRI sequence protocols proved effectively to detect the IAN and LN and their course in healthy volunteers. The tissue composition of the mandibular neurovascular bundle was conclusively distinguishable as was the varying topography inside multiple bony channels.

CLINICAL RELEVANCE

The presented data on the precise and valid visualization of the IAN and LN have clinical implications in respect to local anesthesia prior to dental treatments in the mandible but also regarding surgical procedures and implant insertion in the molar region.

The effect of unilateral lingual nerve injury on the kinematics of mastication in pigs

OBJECTIVE

This study evaluates the effect of unilateral lingual sensory loss on the spatial and temporal dynamics of jaw movements during pig chewing.

DESIGN

X-ray Reconstruction of Moving Morphology (XROMM) was used to reconstruct the 3-dimensional jaw movements of 6 pigs during chewing before and after complete unilateral lingual nerve transection. The effect of the transection were evaluated at the temporal and spatial level using Multiple Analysis of Variance. Temporal variables include gape cycle and phase durations, and the corresponding relative phase durations. Spatial variables include the amplitude of jaw opening, jaw yaw, and mandibular retraction-protraction.

RESULTS

The temporal and spatial dynamics of jaw movements did not differ when chewing ipsilateral versus contralateral to the transection. When compared to pre-transection data, 4 of the 6 animals showed significant changes in temporal characteristics of the gape cycle following the transection, irrespective of chewing side, but the specific response to the lesion was highly dependent on the animal. On the other hand, in affected individuals the amplitude of jaw movements was altered similarly in all 3 dimensions: jaw opening and protraction-retraction increased whereas jaw yaw decreased.

CONCLUSION

The variable impact of this injury in this animal model suggests that individuals use different compensatory strategies to adjust or maintain the temporal dynamics of the gape cycle. Because the amplitude of jaw movements are more adversely affected than their timing, results suggest that maintaining the tongue-jaw coordination is critical and this can come at the expense of bolus handling and masticatory performance.