Endoscopically-assisted extraction of broken roots or fragments within the mandibular canal: a retrospective case series study

PURPOSE

To assess the impact of endoscope-assisted fractured roots or fragments extraction within the mandibular canal, along with quantitative sensory testing (QST) alterations in the inferior alveolar nerve (IAN).

METHODS

Six patients with lower lip numbness following mandibular third molar extraction were selected. All patients had broken roots or fragments within the mandibular canal that were extracted under real-time endoscopic assistance. Follow-up assessments were conducted on postoperative days 1, 7, and 35, including a standardized QST of the lower lip skin.

RESULTS

The average surgical duration was 32.5 min, with the IAN exposed in all cases. Two of the patient exhibited complete recovery of lower lip numbness, three experienced symptom improvement, and one patient remained unaffected 35 days after the surgery. Preoperative QST results showed that the mechanical detection and pain thresholds on the affected side were significantly higher than those on the healthy side, but improved significantly by postoperative day 7 in five patients, and returned to baseline in two patients on day 35. There were no significant differences in the remaining QST parameters.

CONCLUSIONS

All endoscopic surgical procedures were successfully completed without any additional postoperative complications. There were no cases of deterioration of IAN injury, and lower lip numbness recovered in the majority of cases. Endoscopy allowed direct visualization and examination of the affected nerve, facilitating a comprehensive analysis of the IAN.

Relationship of the Degree of Nerve Exposure and Surgical Manipulation and Short-Term Neurosensory Disturbance Following Sagittal Split Ramus Osteotomy: A Prospective Study

BACKGROUND

Neurosensory disturbance (NSD) is a common complication after sagittal split ramus osteotomy (SSRO) due to inferior alveolar nerve (IAN) injury. The impact of intraoperative nerve manipulation on NSD remains debated.

PURPOSE

The purpose of this study was to evaluate the influence of IAN exposure and manipulation during SSRO on functional sensory recovery (FSR).

STUDY DESIGN

This was a single-center, prospective cohort study of 40 patients undergoing SSRO at Mahidol University from December 2020 to December 2021. The inclusion criteria were patients aged 20-34, ASA Class I-II. The exclusion criteria were patients with systemic bone disease, history of head and neck or neurological pathology, previous SSRO, or incomplete data collection.

PREDICTOR VARIABLE

Degree of intraoperative nerve manipulation was divided by the attending surgeon as follows; 1) Nerve fully encased in distal segment and not visible (NS); 2) Nerve encased in distal segment but partially visible (DS); and 3) Nerve partially encased in proximal segment and fully dissected free (PS).

OUTCOME VARIABLES

The area of interest was divided into the lip and chin. The primary outcome was time to FSR. The secondary outcome was subjective patient report, using a visual analogue scale, compared to FSR.

COVARIATES

The covariates were sex, age, skeletal diagnosis, degree of movement, and concomitant genioplasty/subapical procedure.

ANALYSES

Kaplan-Meier survival analysis, Cox proportional hazards regression, and Mcnemar test were utilized. P-value < .05 was significant.

RESULTS

In the lip, the median times to FSR were NS, 2 days; DS, 45 days; PS, 102 days. (Interquartile range: 77,127, 114, respectively) In the chin, the median times to FSR were NS, 23 days; DS, 92 days; PS, 87 days. (Interquartile range: 77, 161, 101, respectively.) Nerve manipulation significantly affected FSR in the lip and chin (P = .001, <0.001, respectively. Cox hazard ratios for DS and PS were lower compared to NS. Patients consistently reported more NSD compared to FSR as per Mcnemar test.

CONCLUSION AND RELEVANCE

After SSRO, FSR in the lip is prolonged when the IAN is partially encased in the proximal segment and released. This raises the question of the efficacy of surgically releasing a partially encased IAN.

System for automatically assessing the likelihood of inferior alveolar nerve injury

Inferior alveolar nerve (IAN) injury is a severe complication associated with mandibular third molar (MM3) extraction. Consequently, the likelihood of IAN injury must be assessed before performing such an extraction. However, existing deep learning methods for classifying the likelihood of IAN injury that rely on mask images often suffer from limited accuracy and lack of interpretability. In this paper, we propose an automated system based on panoramic radiographs, featuring a novel segmentation model SS-TransUnet and classification algorithm CD-IAN injury class. Our objective was to enhance the precision of segmentation of MM3 and mandibular canal (MC) and classification accuracy of the likelihood of IAN injury, ultimately reducing the occurrence of IAN injuries and providing a certain degree of interpretable foundation for diagnosis. The proposed segmentation model demonstrated a 0.9 % and 2.6 % enhancement in dice coefficient for MM3 and MC, accompanied by a reduction in 95 % Hausdorff distance, reaching 1.619 and 1.886, respectively. Additionally, our classification algorithm achieved an accuracy of 0.846, surpassing deep learning-based models by 3.8 %, confirming the effectiveness of our system.

Benefits of Coronectomy in Lower Third Molar Surgery: A Systematic Review and Meta-analysis

PURPOSE

The purpose of this study was to measure and compare coronectomy versus extraction in patients at increased risk for inferior alveolar nerve (IAN) injuries associated with third molar removal in terms of IAN injury and other complications.

METHODS

The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist. We conducted a comprehensive literature search across six databases and the gray literature from July 15 to August 01, 2022. We employed Rayyan software to identify and remove duplicate articles to ensure data integrity. Our research followed the strategy patient (P), intervention (I), comparison (C), outcome (O), and study (S): (P) patients needing lower third molar surgery at higher risk of IAN injury; (I) surgery options, coronectomy or complete extraction; (C) comparisons included reduced risks of nerve injuries, postoperative complications (pain, infection, alveolitis), and increased risks of reoperation, root migration, and extraction; (O) desired outcomes were preventing nerve injuries and reducing other surgical complications; and (S) observational study designs (cohort, case-control). Excluded from consideration were studies involving teeth other than lower third molars, as well as reviews, letters, conference summaries, and personal opinions. To gauge the certainty of evidence, we employed the Grading of Recommendation, Assessment, Development, and Evaluation instrument, selecting the most current papers with the highest levels of evidence for inclusion. The primary outcome variable of our study centered on evaluating the incidence of IAN injury, and secondly, the lingual nerve (LN) injury, the postoperative pain, infection, localized alveolitis, the necessity for surgical reintervention, root migration, and extraction. These assessments were carried out with respect to their chosen operative technique for managing third molars, either coronectomy or extraction, as predictor variables. We also considered covariates such as age, gender, and the presence of systemic diseases in our analysis to account for potential confounding factors. The pooled data underwent rigorous analysis utilizing an inverse variance method with both random and fixed effect models by the "metabin" function in the R program's meta-package. Additionally, we assessed the risk of bias in the selected studies by utilizing the Joanna Briggs Institute's Critical Appraisal Checklist for Studies Reporting Prevalence Data and the Critical Appraisal Checklist for Case Reports.

RESULTS

Of the 1,017 articles found, after applying the inclusion and exclusion criteria, 42 were included in this study (29 cohort and 13 case-control studies), including 3,095 patients from 18 countries. The meta-analysis showed that coronectomy reduced the risk of IAN injury [OR (Odds Ratio): 0.14; 95% CI (confidence intervals): 0.06-0.30; I2 (inconsistency index) = 0%; P = .0001], postoperative pain (OR: 0.97; 95% CI: 0.33-2.86; I2 = 81%; P = .01), and alveolitis (OR: 0.38; 95% CI: 0.13-1.09; I2 = 32.2%; P = .01) when compared to complete tooth extraction. However, it also highlighted a greater risk of reintervention (OR: 5.38; 95% CI: 1.14-25.28; I2 = 0.0%; P = .01).

CONCLUSIONS

This study has demonstrated that coronectomy is associated with a decreased risk for IAN injury and decreased pain and localized alveolitis when compared to complete tooth extraction. However, it is essential to acknowledge the higher likelihood of requiring reintervention with coronectomy. Therefore, clinicians should carefully consider the advantages and potential drawbacks of both techniques and tailor their choices to the unique clinical circumstances of each patient.

Is it possible to predict neurosensory alterations in impacted lower third molar removal based on preoperative imaging procedures? A prospective cohort study

BACKGROUND

Surgical extraction of the lower third molar (LTM) may trigger neurosensory injury of the inferior alveolar nerve, making extraction a real challenge. This study set out to assess whether is it possible to predict neurosensory alterations from preoperative imaging.

MATERIAL AND METHODS

A total of 99 patients underwent 124 impacted lower third molar (ILTM) surgeries. Prior to surgery, panoramic and CBCT images were evaluated in an attempt to predict a neurosensory disturbance. Preoperative data (ILTM position, panoramic radiograph signs, inferior alveolar nerve (IAN) location and its contact with the ILTM roots) and intra/postoperative findings (extraction difficulty and sensitivity alterations) were recorded. Descriptive and bivariate data analysis was performed. Statistical comparison applied the chi-square test, Fisher test, and one-way ANOVA test. Statistical significance was established with a confidence interval (CI) of 95%.

RESULTS

In 4.03% of cases, patients experienced neurosensory alterations. Of 124 ILTM positions in panoramic radiographs, 76 cases were considered to exhibit a potential neurosensory risk as they presented two or more types of superimposed relationships between ILTM and mandibular canal. Of these, alterations were reported in only three cases (3.95%). Of the 48 remaining ILTM images presenting only one sign, neurosensory alterations were observed in two cases (4.17%). No permanent alterations were recorded in any of the five cases observed.

CONCLUSIONS

Within the limitations of the present study, prediction of neurosensory alterations prior to ILTM extraction by means of preoperative imaging did not show a significant statistical correlation with post-surgical incidence. Nevertheless, interruption of the canal´s white line (ICWL) or a diversion of the canal (DC) may predict an increased risk of IAN injury.

Risk assessment of inferior alveolar nerve injury after wisdom tooth removal using 3D AI-driven models: A within-patient study

OBJECTIVE

To compare a three-dimensional (3D) artificial intelligence (AI)- driven model with panoramic radiography (PANO) and cone-beam computed tomography (CBCT) in assessing the risk of inferior alveolar nerve (IAN) injury after mandibular wisdom tooth (M3M) removal through a within-patient controlled trial.

METHODS

From a database of 6,010 patients undergoing M3M surgery, 25 patients met the inclusion criteria of bilateral M3M removal with postoperative unilateral IAN injury. In this within-patient controlled trial, preoperative PANO and CBCT images were available, while 3D-AI models of the mandibular canal and teeth were generated from the CBCT images using the Virtual Patient Creator AI platform (Relu BV, Leuven, Belgium). Five examiners, who were blinded to surgical outcomes, assessed the imaging modalities and assigned scores indicating the risk level of IAN injury (high, medium, or low risk). Sensitivity, specificity, and area under receiver operating curve (AUC) for IAN risk assessment were calculated for each imaging modality.

RESULTS

For IAN injury risk assessment after M3M removal, sensitivity was 0.87 for 3D-AI, 0.89 for CBCT versus 0.73 for PANO. Furthermore, the AUC and specificity values were 0.63 and 0.39 for 3D-AI, 0.58 and 0.28 for CBCT, and 0.57 and 0.41 for PANO, respectively. There was no statistically significant difference (p>0.05) among the imaging modalities for any diagnostic parameters.

CONCLUSION

This within-patient controlled trial study revealed that risk assessment for IAN injury after M3M removal was rather similar for 3D-AI, PANO, and CBCT, with a sensitivity for injury prediction reaching up to 0.87 for 3D-AI and 0.89 for CBCT.

CLINICAL SIGNIFICANCE

This within-patient trial is pioneering in exploring the application of 3D AI-driven models for assessing IAN injury risk after M3M removal. The present results indicate that AI-powered 3D models based on CBCT might facilitate IAN risk assessment of M3M removal.

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.

The effect of root orientation on inferior alveolar nerve injury after extraction of impacted mandibular third molars based on propensity score-matched analysis: a retrospective cohort study

BACKGROUND

The injury of the inferior alveolar nerve (IAN) is one of the most serious complications of impacted mandibular third molars (IMTMs) extraction. The influence of the root orientation of IMTMs on IAN injury is still controversial. A deeper understanding of the risk factors of IAN injury conduces to better prevention of IAN injury. This study aims to explore whether root orientation is an independent risk factor of IAN injury during IMTMs extraction using the statistical strategy of propensity score matching (PSM).

METHODS

This retrospective cohort study included 379 patients with 539 cases of high-risk IMTMs screened by panoramic radiography and cone beam computed tomography. The IAN injury incidence after extraction of different groups of IMTMs was analyzed using the chi-square test or Fisher's exact test. The correlation between third molar root orientation and impaction depth/contact degree with IAN was evaluated by the Lambda coefficient. Based on PSM for balancing confounding factors including age, sex, impaction depth, and contact degree, the effect of root orientation on the incidence of IAN injury was further analyzed using Fisher's exact test.

RESULTS

There were significant group differences in IAN injury incidence in impaction depth, root orientation, and contact degree of root-IAC before PSM. Root orientation was correlated with impaction depth and contact degree of root-IAC. After PSM, there were 9 cases with IAN injury and 257 cases without IAN injury. There were significant group differences between the buccal and non-buccal groups after PSM, and the risk of IAN injury was higher when the root was located on the buccal side of IAC (OR = 8.448, RR = 8).

CONCLUSIONS

Root orientation is an independent risk factor of IAN injury, and the risk is higher when the root is located on the buccal side of IAC. These findings could help better evaluate the risk of inferior alveolar nerve injury before the extraction of IMTMs.

Risk factors observed in 2-dimensional radiographs for permanent injury of the inferior alveolar nerve after removal of mandibular third molars: a case-control study

OBJECTIVE

To assess whether differences exist in signs observed in 2D radiographs of mandibular third molars between a case group of patients with and a control group without permanent sensory disturbance of the inferior alveolar nerve (IAN) after removal.

STUDY DESIGN

Three observers blinded to patient status assessed radiographs from the case group (n=162) and the control group (n=172). Two new signs, craniocaudal relation of the roots and the mandibular canal and position of the canal over the roots; and 4 "classic" signs, interruption of the white borders of the canal, darkening of the roots, narrowing of the canal lumen, and diversion of the canal over the roots were registered. Chi-square tests assessed differences in distribution of radiographic signs between the groups. Odds ratios expressed the association between radiographic signs and permanent sensory disturbance. Inter- and intraobserver reliability values were calculated.

RESULTS

We found significantly more teeth with roots positioned inferiorly to the canal borders (P<0.001; OR 4.1-5.3) and with the canal superimposed over the upper or middle third of the roots (P<0.001; OR 2.6-3.9) in the case group than in the control group. Inter- and intraobserver reproducibility was excellent for roots inferior to the canal borders and fair to good for canal superimposition.

CONCLUSIONS

Two radiographic signs are valid predictors of permanent sensory disturbance of the IAN in 2D radiographs.

What is the Incidence of Late Complications Associated With Lower Third Molar Coronectomy? 10-Year Follow-Up Results

PURPOSE

Coronectomy is an operation to manage impacted third molars (M3s) considered at high risk for mandibular nerve injury but long-term outcomes are still lacking. The purpose of this study was to estimate the risk of late complications occurring within 10 years following lower M3 coronectomy.

METHODS

The investigators designed a prospective cohort study and enrolled a sample of 94 patients treated with coronectomy of third mandibular molars at the Unit of Oral and Maxillofacial Surgery of the University of Bologna, from 2009 to 2012. This follow-up study included all of the patients from the original study who completed 10 years of follow-up. The primary outcome variables is postoperative late complication occurring between 5 and 10 years after coronectomy coded as present or absent. Late complications were defined as root exposure, nerve injury, pulpitis, periapical infection, and reoperation. The secondary outcome variable was probing pocket depth. Covariates examined were age, smoking and type of M3 impaction. Descriptive statistical analyses were performed.

RESULTS

The inception cohort was composed of 94 subjects who had 116 coronectomies (k) completed. The study cohort was composed of subjects with 10 years of follow-up and included 48 subjects (k = 60) with a mean age of 28.99 ± 8.9 years. Between years 5 and 10 of follow-up, 2 subjects (4%) have complications; all root exposures diagnosed at years 8 or 9 after surgery. In another case root removal was required for orthodontics reason. No case of nerve injury to the inferior alveolar nerve occurred, and no periapical infection was observed around the residual roots. The mean 10-year probing pocket depth was 3.31 ± 0.92 mm (1,66-5,66 mm). There were too few complications to identify risk factors for late complications.

CONCLUSIONS

Within all the limitations of this study, the results of this prospective study imply that coronectomy is a useful surgical technique for the treatment of M3s at high neurological risk, to avoid nerve injury to the inferior alveolar nerve. In addition, after coronectomy, retained roots did not develop late infection or periapical infection in the long term. However, in a few cases, removal of retained roots was required at 10 years, due to root migration in the oral cavity. The risk for late complications is uncommon, but persistent.

Mental nerve shielding from possible injury during mandibular surgical procedures: technical note

Injuries to the mental nerve are not an uncommon complication in maxillofacial surgeries. Manipulation close to the mental nerve poses a great risk of nerve injury from drills, bone cutting and trimming burs, and oscillating/reciprocating saws. Nerve injuries can be painful and affect the patient's quality of life. The accompanying complication of the nerve injury depends on the severity of the damage inflicted and can range from transient hypoesthesia to neuropathic pain or trigeminal neuralgia. It is considered that direct injury to the nerve may lead to permanent damage and more severe postoperative clinical symptoms than indirect injuries caused by nerve stretching or during endosteal implant fixation. This technical note describes a technique for shielding the mental nerve and protecting it from rotary drill injury during mandibular inferior border recontouring, orthognathic surgeries, and mandibular body fracture fixation.

Extraction of impacted mandibular third molars in close proximity to the inferior alveolar canal with coronectomy-miniscrew traction to avoid nerve injury

OBJECTIVES

Extraction of impacted mandibular third molars (IMTMs) is the most common surgery performed in the Department of Oral and Maxillofacial Surgery. Inferior alveolar nerve (IAN) injury is a rare but severe complication, and the risk is significantly higher in cases of IMTM near the inferior alveolar canal (IAC). The existing surgical method to extract such IMTMs is either not safe enough or is time-consuming. A better surgical design is needed.

MATERIALS AND METHODS

From August 2019 to June 2022, 23 patients underwent IMTM extraction by Dr. Zhao at Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Nanjing University, and were found to have IMTMs in close proximity to the IAC. Due to high IAN injury risk, these patients underwent coronectomy-miniscrew traction to extract their IMTMs.

RESULTS

The time between coronectomy-miniscrew insertion and complete removal of the IMTM was 32.65 ± 2.110 days, which was significantly shorter than that of traditional orthodontic traction. Two-point discrimination testing revealed no IAN injury, and no injury was reported by patients during follow-up. Other complications, such as severe swelling, severe bleeding, dry socket, and limited mouth opening, were not observed. Postoperative pain levels were not significantly higher in the coronectomy-miniscrew traction group than in the traditional IMTM extraction group.

CLINICAL RELEVANCE

For IMTMs that are in close proximity to the IAC and must be extracted, coronectomy-miniscrew traction is a novel approach to minimize the risk of IAN injury in a less time-consuming way with a lower possibility of complications.

Early root migration after a mandibular third molar coronectomy

PURPOSE

This prospective cohort study aimed to assess early root migration after a coronectomy of the mandibular third molar at 2 and 6 months after surgery.

METHODS

We included all patients treated with a coronectomy of an impacted mandibular third molar. The primary outcome measure was the extent of postoperative root migration after 2 and 6 months. Migration was measured as the distance between the root complex and a fixed point on the inferior alveolar canal. The secondary aim was to identify factors (age, impaction pattern, and patient sex) that affected the extent of root migration.

RESULTS

One hundred and sixty-five coronectomies were performed in 141 patients (96 females and 45 males; mean age 33.1 years, SD 16.0). The 2-month checkup was completed by 121 patients that received 141 coronectomies. The 6-month check-up was completed by 73 patients that received 80 coronectomies. The mean root migrations were 3.30 mm (SD 2.53 mm) at 2 months and 5.27 mm (SD 3.14 mm) at 6 months. In the 2-6-month interval, the mean root migration was 2.58 mm (SD 2.07 mm). The extents of migration were similar during the 0-2-month interval and the 2-6-month interval (p = 0.529). Younger age was associated with greater root migration, and females experienced significantly greater migrations than males (p = 0.002).

CONCLUSION

Roots migrated more rapidly in the first two postoperative months, compared to the 2-6-month interval. Age was negatively correlated with the extent of root migration, and females showed significantly greater migrations than males.

[Microanatomy features in third molars roots adjacent to mandibular canal]

THE PURPOSE

Of the study is to reduce the risk of postoperative neuropathy of the inferior alveolar nerve by improving diagnostic methods, assessment of individual topographic and anatomical features and extraction technique of impacted teeth adjacent to the mandibular canal.

MATERIALS AND METHODS

According to the CBCT examination, orthopantomography and macroscopic examination of removed third molars roots (n=140) the relative position of the mandibular canal and the roots of the third molars were studied.

RESULTS

Three variants of close mandibular canal and third molars position have been identified. In the lateral and apical nerve position, the root surface depressions were detected. With inter-radicular position fit, the mandibular canal and the nerve bundle form a «bed» in between impacted tooth roots.

CONCLUSION

The injury of neurovascular bundle prognosis during extraction with an interadicular mandibular position depends on roots anatomy and their convergence degree. If the interradicular distance is less than the diameter of the mandibular canal, nerve injury during tooth extraction is inevitable, in such cases coronectomy is indicated.

Influence of Inferior Alveolar Nerve Exposure During Sagittal Split Osteotomy on the Rate and Timing of Baseline Sensory Recovery

PURPOSE

Neurosensory disturbance is the most common consequence of sagittal split osteotomy (SSO). The purpose of this study is to quantitatively assess neurosensory deficiency and recovery to the preoperative status when the inferior alveolar nerve (IAN) was exposed versus unexposed during SSO.

METHODS

This is a single-center, prospective, cohort study of all patients undergoing bilateral SSO between August 2018 and July 2019. Patients were included in the study sample if they underwent bilateral SSO with an intact intraoperative IAN and were received follow-up assessment for at least a year. The predictor variable was the intraoperative IAN status (exposed vs unexposed). The outcomes of interest were the rate and timing of recovery to the preoperative status. The covariates were age, sex, and the magnitude and direction of surgical movements. Neurosensory function was quantitatively evaluated using the Semmes-Weinstein monofilament test at follow-up intervals of 1, 3, 6, and 12 months. Descriptive statistics, bivariate statistics, Cox proportional hazards regression, and Kaplan-Meier analyses were performed. P value <.05 was considered statistically significant.

RESULTS

Of 90 patients, 86 patients who underwent 172 SSOs were included in this study. The mean age was 22.95 ± 3.34 years (range, 17 to 30), 65 were women, and the range of surgical movements was 3 to 8.3 mm of advancement and 2 to 12 mm of setback. Eighty-five nerves (49.4%) were allocated to the unexposed group, and 87 (50.6%) to the exposed group, with statistically significant differences in the rate and timing of recovery (hazard ratio = 2.368; 95% confidence interval, 1.662 to 3.376; P < .001). Among those with recovered nerves, the median time to recovery was 90 days in the unexposed group and 364 days in the exposed group (P < .0001).

CONCLUSIONS

IAN exposure during SSO is associated with an increased risk of neurosensory deficiency and an increased time of sensory recovery to the baseline threshold in patients aged 17 to 30 years. When the IAN remained fully enclosed in the canal of the distal segment, only 11% of patients had a measurable sensory deficit 1 year after surgery. In those patients with any degree of IAN exposure, 36% had a residual sensory deficit 1 year after surgery.

Coronectomy: An Alternative to Complicated Full-Bony Impacted Tooth Removal

The removal of impacted teeth is a common office-based oral and maxillofacial surgical procedure. Complications associated with the procedure are uncommon; however, in the mandible, close proximity of the third molars to the inferior alveolar nerve can potentially lead to temporary or permanent sensory disturbances. The intentional partial odontectomy (coronectomy) procedure is a surgical option aimed at mitigating and reducing the incidence of this potential risk and complication.

Etiology and pattern of maxillofacial trauma

Introduction

Maxillofacial trauma can be limited to superficial lacerations, abrasions, and facial bone fractures. The objective of this study was to determine the etiology, pattern, and predictors of soft tissue and bony injuries.

Materials and methods

This study was conducted in the department of maxillofacial surgery Lady Reading hospital Pakistan from Jan 2019 to June 2021. The nonprobability consecutive sampling technique was used for the selection of patients. All patients were assessed clinically and radiologically. The neurosensory examination was done for any altered sensation, anesthesia, or paresthesia. Motor nerve function was also assessed clinically. Data were analyzed using SPSS version 26. The etiology and pattern of maxillofacial trauma were stratified among age and genders using the chi-square test to see effect modifiers. Tests for regression analysis were also applied. P≤0.05 was considered significant.

Results

A total of 253 patients meeting inclusion criteria were included in this study. The majority of these patients were males, 223 (88.1%), while only 30 (11.9%) were females. The mean age for the group was 25.4 ± 12.6 years. RTAs were the most common causes of trauma (63.6%) followed by assault (15.0%), falls (11.5%), FAIs (5.9%), and sports (0.4%). The most vulnerable skeletal part was the mandible (22.9%) followed by Zygoma (7.1%), significantly predicted by RTAs. Soft tissue laceration analysis showed a high frequency of multiple lacerations (38%) significantly predicted by FAIs. The frequency of trigeminal nerve injury was 5.5% (14 patients) and that of the facial nerve was 1.6% (4 patients). The strongest association of nerve injury was with firearm injury (47%), followed by road traffic accidents and sports injuries.

Conclusion

Road traffic accident was the most common etiological factor and mandible fracture was commonly predicted by RTA. Trigeminal nerve injuries were common, frequency of nerve injuries was highly associated with mandible fracture and was predicted by FAI.

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).

[Evaluating the risk factors of inferior alveolar nerve injury following removal of the mandibular third molars]

Objective: To evaluate the risk factors of inferior alveolar nerve injury (IANI) after surgical removal of the mandibular third molars (M3) and present a new risk scoring system to predict the probability of IANI. Methods: Patients who underwent extraction of M3 in the Stomatology Hospital, Zhejiang University School of Medicine from April 2017 to December 2019 were involved. The investigators enrolled a sample composed of 949 mandibular third molars. Prediction model was used for univariate and multivariate analysis of gender, age, M3, inferior alveolar canal (IAC), and the contact between M3 and IAC, to assess the risk factors of IANI. Combined with the risk factors determined by the outcomes of prediction model, the risk scoring system was constructed. The diagnostic performance of each cut-off score was examined to conduct a risk stratification of IANI risk scores. The predictive ability and reliability of the model were evaluated. Results: In prediction model, twenty nine cases (4.4%, 29/664) experienced postoperative IANI. Number of root (P<0.01), depth of impaction (P<0.05), contact between M3 and IAC (P<0.01) and their contact position (P<0.05) were statistically significant as contributing risk factors of IANI. Specifically, the incidence of temporary IANI was higher in those who aged under 25 years (P<0.001), while female suffer more permanent injury (P<0.05). Based on the IANI risk scoring system, patients were stratified into low-risk, middle-risk and high-risk groups at cutoff scores of 3 and 4. The area under the receiver operator characteristic curve of the risk scoring system were 0.81 [95%CI (0.70-0.90), P=0.002] and 0.80 [95%CI (0.68-0.92), P=0.007] towards good discrimination. Conclusions: Age, gender, number of root, depth of impaction, and contact between M3 and IAC were risk factors of IANI. IANI risk scoring system might help in preoperative assessment, recognition of high-risk cases and decision-making to reduce IANI.

Trigeminal nerve injuries. Four years' experience at a single Argentine referral center and a literature review

The aim of this retrospective study was to describe the etiology and characteristics of trigeminal nerve injuries referred to a specialized center in Buenos Aires, Argentina. A retrospective analysis was performed of patients referred from February 2016 to January 2020. Age, sex, intervention performed, nerve affected, time elapsed from injury, diagnosis, location, and whether patient had signed informed consent were recorded. A descriptive analysis of the data was made, and 95% confidence intervals were calculated for prevalence. The study sample consisted of 30 subjects (31 nerve injuries), 19 female and 11 male, average age (±SD) 40 ± 17 years. The inferior alveolar nerve was the most frequently injured nerve (74%,) while the lingual nerve accounted for 26%. The most common etiologies were inferior molar extractions (47%), dental implants (20%), and local anesthesia (13%). Other etiologies were autologous mandibular bone grafts for dental implants, removal of cysts associated with the inferior third molar, and endodontic treatment. Dental Institutions at which treatment was provided were found to be significantly associated with patients being warned and asked to sign informed consent (p<0.05), while dentists working at private offices requested fewer consents. The most frequent symptom was paresthesia, and 5 patients suffered spontaneous or evoked pain. Only 2 patients intended to file legal claims. Dentists should be aware of the debilitating effects resulting from trigeminal injuries, the complexity of their resolution and the importance of carefully planning dental procedures to prevent them.

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.

Long-term neurosensory disturbances after modified sagittal split osteotomy

We have investigated the long-term incidence of neurosensory disturbances after modified bilateral sagittal split osteotomy, and identified associated risk factors. We prospectively studied 376 patients, and their self-reported neurosensory disturbances were evaluated six months, and one, two, and three years postoperatively. The correlations between the following risk factors and neurosensory disturbances were investigated using univariate analysis and stepwise multivariate analysis: age at operation, sex, type of movement (advancement, setback, or rotation), concurrent genioplasty, type of detachment, iliac crest bone graft, and use of dicalcium phosphate synthetic bone graft. Probabilities of less than 0.05 were accepted as significant. Three years postoperatively, 57 patients (15%) reported altered sensation of the lower lip or chin. Older age correlated significantly with neurosensory disturbances (p<0.0001). Greater mandibular advancement correlated with postoperative "positive" neurosensory phenomena (right side p=0.08; left side p=0.03). Intraoperative surgical manipulation of the left inferior alveolar nerve was significantly associated with postoperative hypoaesthesia (p=0.014). Older age at surgery, extensive mandibular advancement, and surgical manipulation of the left inferior alveolar nerve, were associated with long-term neurosensory disturbances after modified bilateral sagittal split osteotomy. The modified operation seems to safeguard the inferior alveolar nerve from transection, without causing damage to other nerves.

Effects of inferior alveolar nerve rupture on bone remodeling of the mandible: A preliminary study

Although various animal studies have indicated that sensory nerves played an important role in bone metabolism and nerve injury could impair the process of bone remodeling, the actual effect of sensory nerve rupture on human bones remains unclear. The aim of this preliminary study was to investigate the effect of inferior alveolar nerve (IAN) rupture on mandibular bone remodeling of patients underwent bilateral sagittal split ramus osteotomy (BSSRO).Ten patients with unilateral IAN rupture during BSSRO were involved in this study. Neurosensory examinations were employed to assess the sensory function of bilateral IAN. The remodeling process of the post-operational mandible was evaluated by panoramic radiographs and computed tomography (CT) scans.Neurosensory examinations indicated that nerve rupture resulted in significant hypoesthesia at the IAN-rupture side. Assessment of panoramic radiographs showed no evident alterations of bone structure at the IAN-rupture side of mandible. Evaluation of CT images also indicated no statistical difference in bone density and thickness between IAN-rupture side and contralateral side.Accordingly, our study indicated that IAN rupture may not significantly impair the short-term bone remodeling process of human mandible.

Transoral video assisted thyroidectomy: a systematic review

INTRODUCTION

The aim of this study is to perform a review of the English-language international literature concerning thyroid surgery performed through the transoral vestibular approach, to evaluate its flessibility and safety in terms of complications.

MATERIALS AND METHOD

The review was carried out on 17 studies of 17 different Authors. The following variables were taken into consideration: first Author's name, nationality, year of publication, number of cases, hospital stay, conversion rate, type of surgical approach, total number of total thyroidectomies and loboisthmectomies, operative time range, intraoperative blood loss range, number and percentage of complications.

RESULTS

736 procedures were performed: 289 total thyroidectomies and 447 loboisthmectomies. Surgical approach was trivestibular in 15 cases and combined (oro-vestibular) in 2 cases. The operative time varies from 43 minutes for a loboisthmectomy to 345 for a total thyroidectomy. Intraoperative blood loss ranges from 3 to 300 ml. Ten cases were converted into open surgery. The hospital stay varies from 1 to 10 days. Complications were: transient recurrent laryngeal nerve palsy in 34 cases, permanent in 2 cases; transient hypoparathyroidism in 62 cases. One case of postoperative bleeding, 22 postoperative seroma, 20 cases of mental nerve injury, 8 cases of operative wound infection.

CONCLUSIONS

Transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a new surgical method, the use of which exclusively meets the aesthetic needs of some patients. Its specific complication is the injury of the mental nerves. Further studies, however, seem to be necessary, on numerically broader cases, to ascertain the real validity of the method.

Liposuction of the Neck: Low Incidence of Nerve Injury and Other Complications in 987 Patients

<p>The neck is one of the most common areas treated by liposuction. Neck liposuction decreases fat volume, causes skin contraction, and restores a more youthful appearance. We present a large case series (n=987) performed by three dermatologic surgeons. Five patients developed temporary post-operative marginal mandibular dysfunction, one patient had submandibular gland ptosis and one patient had arterial bleeding. Seroma, skin necrosis, scarring, and hyperpigmentation did not occur following neck liposuction. Neck liposuction performed with tumescent local anesthesia is a safe procedure associated with a low incidence of nerve injury and other complications.</p> <p><em>J Drugs Dermatol. 2018;17(1):30-34.</em></p>.

Trigeminal Neuralgia Following Lightning Injury

Lightning and other electrical incidents are responsible for more than 300 injuries and 100 deaths per year in the United States alone. Lightning strikes can cause a wide spectrum of neurologic manifestations affecting any part of the neuraxis through direct strikes, side flashes, touch voltage, connecting leaders, or acoustic shock waves. This article describes the first case of trigeminal neuralgia induced by lightning injury to the trigeminal nerve, thereby adding a new syndrome to the list of possible lightning-mediated neurologic injuries.

Complications after orthognathic surgery: our experience on 423 cases

INTRODUCTION

Orthognathic surgery is widely used to correct dentofacial discrepancies. However, this procedure presents numerous possible complications. The aim of our study is to review intraoperative and postoperative complications related to orthognathic surgery based upon a 10-year period in the Maxillofacial Surgery Department of Federico II University of Naples.

MATERIALS AND METHODS

Medical records of 423 patients who undergone orthognathic surgery in a 10-year period were retrospectively analyzed and complications was noted. Statistical analysis was conduced in order to understand if the type of surgical procedure influenced complications rate.

RESULTS

One hundred eighty-five complications in 143 (33.8%) of the 423 treated patients were reported. Complications detected were nerve injury (49 cases, 11.9%), infections (10 cases, 2.4%), complications related to fixation plates or screws (30 cases, 7.1%), bad split osteotomy (8 cases, 1.9%), secondary temporo-mandibular joint disorders (36 cases, 8.5%), dental injuries (21 cases, 5%), condilar resorption (2 cases, 0.5%), and necessity of a second-time surgery (24 cases, 5.7%).

CONCLUSIONS

Serious complications seem to be quite rare in orthognathic surgery. Some of the surgical complications found are related to the surgeon experience and not strictly to the risks of the operation itself. Understanding potential complications allows the surgeon to guarantee safe care through early intervention and correctly inform the patient in the preoperative colloquy.

Nerve damage in dentistry

Many forms of dental treatment have the potential to cause injury to the oral branches of the trigeminal nerve, including local anesthetic injections, root canal therapy, implant insertion, bone grafting, and dentoalveolar surgery. Based on the records of a referral center with more than 30 years' experience in managing 3200 of these injuries, this article reviews etiology and prevention; suggests criteria for referral of patients; and discusses treatment for the various types of injury and the results of such treatment.

Management of endodontic injuries to the inferior alveolar nerve

OBJECTIVE

Functional sensory recovery from microsurgical intervention for inferior alveolar nerve (IAN) injuries resulting from endodontic treatment were evaluated using a retrospective chart review. Other variables assessed included time from injury to surgery as well as other factors which improved functional neurosensory recovery (FSR).

METHOD AND MATERIALS

This case series of seven patients evaluated the outcome of IAN microsurgery following endodontic-related nerve injuries. All patients were referred, evaluated, and operated on by the primary investigator (VBZ). Surgical intervention consisted of external and/or internal neurolysis with irrigation of the mandibular canal and decompression of the affected IAN as well as allogeneic nerve graft in one patient. Preoperative and postoperative sensory levels were recorded and FSR was assessed using the Medical Research Council scale.

RESULTS

Seven subjects with a mean age of 35.57 years (range 22 to 55 years old) opted to undergo trigeminal nerve microsurgery for management of their IAN injury resulting from endodontic treatment of mandibular molar teeth. Six women and one man were included in this population. The majority of subjects presented with an initial chief complaint of dysesthesia and hypoesthesia. The mean interval between nerve injury and surgical treatment was 15 weeks (range 1 to 40 weeks). All patients had preoperative sensory level of S0, S1, or S2+, and achieved FSR following surgery. Two patients had postoperative sensory level of S3, four patients had a postoperative sensory level of S3+, and one had a postoperative sensory level of S4 (complete recovery).

CONCLUSIONS

The results of this study suggest that trigeminal nerve microsurgery for the surgical treatment of endodontic injuries to the IAN can improve neurosensory function. Surgical intervention in this study was beneficial to alleviate neurosensory deficits and symptoms for those injuries to the IAN caused by endodontic treatment.

Influence of anatomic position and intraoperative exposure of the inferior alveolar nerve on neurosensory disturbance after sagittal split ramus osteotomy: a three-dimensional computed tomography study

OBJECTIVE

To evaluate the influence of the anatomic position and intraoperative exposure of the inferior alveolar nerve on neurosensory disturbance (NSD) in sagittal split ramus osteotomy.

STUDY DESIGN

The anatomic factors of the nerve were measured on preoperative three-dimensional computed tomography in 98 patients. The intraoperative nerve exposure was assessed. NSD was evaluated for 1 year after surgery. The correlations between NSD and the factors were analyzed.

RESULTS

The NSD decreased as the lateral marrow space from the nerve increased (P < .01). The complete nerve exposure increased NSD by 7.6 times (P = .01). The nerve exposure increased as the buccal plate thickness increased (P = .01) and decreased as the vertical marrow space from the nerve increased (P = .01).

CONCLUSIONS

The nerve exposure and the lateral marrow space from the nerve affected NSD. The buccal plate thickness and the vertical marrow space indirectly affected NSD through nerve exposure.

Influence of tooth sectioning technique and various risk factors in reducing the IAN injury following surgical removal of an impacted mandibular third molar

A prospective study on 100 patients presented with a mesioangular impacted mandibular third molar in close proximity to the inferior alveolar nerve canal (IANC) was done to evaluate the efficacy of tooth sectioning in reducing the incidence of inferior alveolar nerve (IAN) injury during their surgical removal. The patients were divided into two groups: group A, where tooth sectioning was not performed, and group B, where tooth sectioning was performed. Patients were recalled 7 days, 15 days, 30 days, 3 months, and 6 months postoperatively for evaluation of nerve injury and its recovery. A total of 13 patients suffered from nerve damage out of which 10 patients (10/50 or 20 %) belonged to group A and 3 patients (3/50 or 6 %) belonged to group B. All patients showed complete recovery from nerve damage within 6 months except 1 patient. The result of the study showed that tooth sectioning significantly reduces the incidence of nerve damage by 14 %. Deviation of the IANC, increased depth of the impacted tooth, intraoperative hemorrhage within socket/nerve exposure, and increased duration of procedure were found to be the significant risk factors associated with nerve injury.

Clinical relevance of cone beam computed tomography in mandibular third molar removal: A multicentre, randomised, controlled trial

PURPOSE

The aims of this study were to investigate the effectiveness of cone beam computed tomography (CBCT) compared to panoramic radiography (PR), prior to mandibular third molar removal, in reducing patient morbidity, and to identify risk factors associated with inferior alveolar nerve (IAN) injury.

MATERIAL AND METHODS

This multicentre, randomised, controlled trial was performed at three centres in the Netherlands. Adults with an increased risk for IAN injury, as diagnosed from PR, were included in the study. In one arm of the study, patients underwent an additional CBCT prior to third molar surgery. In a second arm of the study, no additional radiographs were acquired. The primary outcome measure was the number of patient-reported altered sensations 1 week after surgery. As secondary outcome measures, the number of patients with objective IAN injury, with long-term (>6 months) IAN injury, the occurrence of other postoperative complications, the Oral Health Related Quality of Life-14 (OHIP-14) questionnaire responses, postoperative pain (visual analogue scale score), duration of surgery, number of emergency visits, and number of missed days of work or study were scored.

RESULTS

A total of 268 patients with 320 mandibular third molars were analysed according to the intention-to-treat principle. The overall incidence of IAN injury 1 week after surgery was 6.3%. No significant differences between CBCT and PR for temporary IAN injury (p = 0.64) and all other secondary outcomes were registered. A lingual position of the mandibular canal (MC) and narrowing, in which the diameter of the MC lumen was decreased at the contact area between the MC and the roots, were significant risk factors for temporary IAN injury.

CONCLUSION

Although CBCT is a valuable diagnostic adjunct for identification of an increased risk for IAN injury, the use of CBCT does not translate into a reduction of IAN injury and other postoperative complications, after removal of the complete mandibular third molar. In these selected cases of a high risk for IAN injury, an alternative strategy, such as monitoring or a coronectomy, might be more appropriate. (http://clinicaltrials.gov, NCT02071030).

Nerve damage related to implant dentistry: incidence, diagnosis, and management

Proper patient selection and treatment planning with respect to dental implant placement can preclude nerve injuries. Nevertheless, procedures associated with implant insertion can inadvertently result in damage to branches of the trigeminal nerve. Nerve damage may be transient or permanent; this finding will depend on the cause and extent of the injury. Nerve wounding may result in anesthesia, paresthesia, or dysesthesia. The type of therapy to ameliorate the condition will be dictated by clinical and radiographic assessments. Treatment may include monitoring altered sensations to see if they subside, pharmacotherapy, implant removal, reverse-torquing an implant to decompress a nerve, combinations of the previous therapies, and/or referral to a microsurgeon for nerve repair. Patients manifesting altered sensations due to various injuries require different therapies. Transection of a nerve dictates immediate referral to a microsurgeon for evaluation. If a nerve is compressed by an implant or adjacent bone, the implant should be reverse-torqued away from the nerve or removed. When an implant is not close to a nerve, but the patient is symptomatic, the patient can be monitored and treated pharmacologically as long as symptoms improve or the implant can be removed. There are diverse opinions in the literature concerning how long an injured patient should be monitored before being referred to a microsurgeon.

Assessment of difficulty in third impacted mandibular molar surgery: the Conti Scale

AIM

We suggest a numerical method for the preoperative assessment of difficulty in mandibular third molar surgeries.

METHODS

This study enrolled 1000 subjects ranging in, age from 17 to 91 years, who presented to the Clinic of Maxillary Facial Surgery at the, University of Florence in Italy, for impacted mandibular third molars removal in 2013. The difficulty of extraction was analyzed for each patient.

RESULTS

Comparison of preoperative difficulty assessment scores with the actual difficulty encountered by an operator, confirming the reliability of our protocol.

CONCLUSION

Careful preoperative analysis of the extraction difficulties and correct surgical planning can reduce intra and postoperative complications, in the third impacted mandibular molar surgeries. The use of an easy and rapid method for the assessment of difficulty in third molar surgeries, is an efficient clinical methodology for preoperative analysis.

Implant-related nerve injuries

Injuries to branches of the trigeminal nerves are a known complication during dental implant placement. These injuries tend to be more severe than those experienced during other dentoalveolar procedures. This article reviews the types of nerve injuries and areas and situations of which clinicians should be cognizant when placing dental implants. Strategies to avoid injuries, and a management algorithm for suspected nerve injuries, are also discussed.

Inferior alveolar nerve laceration after implant site preparation: A case report

PURPOSE

The aim of this article is to present a referred clinical case of an inferior alveolar nerve laceration during the insertion of a dental implant in the mandible, that came to our attention after the injury.

MATERIALS AND METHODS

A 71-year-old female was treated by a colleague in order to be rehabilitated with a fixed implant-supported prosthesis for her missing teeth in positions 44, 45 and 46. After implant site osteotomy in region 46, the speed of the surgical motor was not changed; as a consequence, the implant was inserted at 1200 rpm and intruded into the mandibular canal, causing the laceration of the neurovascular bundle.

RESULTS

During the first 2 weeks after surgery the patient complained of paresthesia in the mental and lower lip area, with labial ptosis and drooling. After 14 days, the paresthesia reduced and mucosal and gingival normosensitivity was detected; however, the patient complained about hyperesthesia of the lower inside lip. After 21 days, the lower lip tone and function were almost completely restored and the paresthesia was further reduced, however the hyperesthesia persisted.

CONCLUSIONS

It is extremely important to pay attention to preventing neurological complications through proper preoperative planning, careful execution of the surgical techniques and correct management of instruments and motor speed settings. The latter procedure should be double-checked by both the operator and the assistant.

Post-extraction inferior alveolar nerve neurosensory disturbances--a guide to their evaluation and practical management

Inferior alveolar nerve injuries are a recognised complication of mandibular third molar extractions. This paper describes the different types of nerve injuries that may occur. A differential of possible causes is provided and an approach to the immediate and follow-up management is outlined. The prognosis of such injuries is reviewed so that patients can be informed of the possible postoperative outcome. The algorithm shows the timeline for monitoring/referring and the included tables outline the advantages and disadvantages of surgery versus watchful waiting.

Inferior alveolar and mental nerve injuries associated with open reduction and internal fixation of mandibular fractures: a Seven Year retrospective study

PURPOSE

To document adverse neurosensory changes in the inferior alveolar nerve (IAN) and mental nerve (MN) after surgical mandibular fracture treatment and to identify risk factors associated with these changes.

MATERIALS AND METHODS

A retrospective study of patients surgically treated for mandibular fractures. The primary study variable was the postoperative change in IAN/MN neurosensory examination after fracture fixation. Risk factors were categorized as demographic, anatomic, experience of the operator, fracture displacement and number of miniplates placed at each fracture site. Appropriate statistics were computed.

RESULTS

209 patients with 293 fractures were analysed. One hundred twenty fractures (41%) were located between the lingula and mental foramen, and 173 fractures (59%) were located distal to the mental foramen. Two hundred seventeen (41%) were displaced by 5 mm or more. In 38 fractures (13%), the IAN/MN neurosensory status worsened after treatment. In a multivariate model, fracture displacement, operator inexperience and two plate fixation were associated with a statistically significant risk (P ≤ 0.05) for postoperative deterioration of IAN/MN sensation.

CONCLUSION

Fixation with two miniplates, fracture displacement of 5 mm or more and operator inexperience were associated with an increased risk for deterioration of the IAN/MN neurosensory status after treatment of mandibular fractures.

Complications in implant dentistry

The mainstream use of dental implants has allowed millions of patients to benefit from the predictability of dental implant therapy and, in many instances, dental implants have become the standard of care. Even though success rates in implant dentistry are well above 90 percent, complications do occur. Most complications are preventable with proper planning and execution. Others are inherent to the risks of surgery and may require intervention. The purpose of this paper is to classify the possible complications that may occur and to discuss their prevention and management.

Our experience in complications of orthognathic surgery: a retrospective study on 3236 patients

BACKGROUND AND OBJECTIVES

From 1989 to 2009, at the Department of Cranio-Maxillo-Facial Surgery, Umberto I Polyclinic, "Sapienza" University of Rome, 3236 patients affected by maxillo-mandibular malformations were submitted to orthognathic surgery, by means of rigid internal fixation. Follow-up highlighted the surgical complications and the possible functional and/or esthetical disorders in the treatment of those pathologies. The data collected have been compared with the ones reported in the literature.

MATERIALS AND METHODS

3236 patients were evaluated clinically and radiographically. The X-rays have been performed before the study, after 24-48 hours, at 6 months and year after surgery.

RESULTS

The most frequent surgical complication was the mandibular nerve sensitivity deficit (19%), irreversible only in 2% of the cases. Temporomandibular joint disorders (TMD), which are widely reported in the international literature, have been relevant in our study too. In particular, TMD occurred in those patients who were already affected by the disorder (from 28.3% to 18.1%); besides, in 11% of cases the symptom appeared after surgery and was treated by means of splint or physiotherapy. Infectious complications occurred in 2% of cases and fractures of the bone elements in 1.5% of cases. The other complications quoted internationally occurred in an irrelevant percentage in our study.

CONCLUSIONS

We believe that orthognathic surgery complications are quite rare and the percentages reported both in our study and in the literature have to be considered as surgical mistakes related to the surgeon experience or as real complications of the orthognathic surgery. Furthermore, as the success of this kind of surgery depends upon many factors, surgical complications represent only one of the causes of the failure. Other causes could be mistakes in planning, unsuitable orthodontic treatment and, finally, an unsuitable assessment of the patients' esthetical and functional problems.

Lingual and inferior alveolar nerve injuries after third molar removal

Trigeminal nerve injury is a rare, but serious complication of a common procedure, which results in a clinically relevant problem that deserves attention. The emergence of microsurgical repair of trigeminal injury has provided clinicians with treatment options for patients who experience persistent neurosensory deficits. The area of microsurgical repair of trigeminal nerves is now in its adolescence. While great strides have been made in the field since its conception, it is certain that a new generation of oral and maxillofacial surgeons wil bring further progress to the field. In the future, better quantitative sensory testing methods, more accurate imaging modalities, and advances in surgical technique will certainly improve the management of patients with impacted third molars. As clinicians, every day we are confronted with the management of impacted third molars. It is important to evaluate each patient individually with an appropriate clinical and radiographic exam. Every patient should be informed of the relative risks and benefits of third molar removal and a joint decision should be reached between the clinician and patient regarding ideal treatment. However, even with ideal management, complications will occur. If a patient does present with signs of a nerve injury the clinician should carefully document the neurosensory deficit and monitor the patient over time. If the patient exhibits a significant sensory deficit for more than one month a referral for evaluation to a tertiary care center capable of surgical repair of the injury is recommended. The occurrence of a "trigger" or Tinel's like sign is improtant as an indication for surgery but may not occur for a month after injury.

Permanent nerve damage from inferior alveolar nerve blocks: a current update

Permanent nerve involvement has been reported following inferior alveolar nerve blocks. This study provides an update on cases reported to one unit in the preceding six years. Lidocaine was associated with 25 percent of cases, articaine with 33 percent of cases, and prilocaine with 34 percent of cases. It does appear that inferior alveolar nerve blocks can cause permanent nerve damage with any local anesthetic, but the incidences may vary.

An uncommon clinical feature of IAN injury after third molar removal: a delayed paresthesia case series and literature review

After an inferior alveolar nerve (IAN) injury, the onset of altered sensation usually begins immediately after surgery. However, it sometimes begins after several days, which is referred to as delayed paresthesia. The authors considered three different etiologies that likely produce inflammation along the nerve trunk and cause delayed paresthesia: compression of the clot, fibrous reorganization of the clot, and nerve trauma caused by bone fragments during clot organization. The aim of this article was to evaluate the etiology of IAN delayed paresthesia, analyze the literature, present a case series related to three different causes of this pathology, and compare delayed paresthesia with the classic immediate symptomatic paresthesia.

Bruxism elicited by inferior alveolar nerve injury: a case report

The aim of this case report is to describe the history of a patient who received an injury to the right inferior alveolar nerve after placement of a dental implant, with bruxism noted afterward. The symptoms were managed by the use of an occlusal appliance worn at night and occasionally during the day, associated with increased awareness of parafunction during the day to reduce muscle pain and fatigue. Paresthesia of the teeth, gingiva, and lower lip persisted but were reduced during appliance use.

Profiling of patients presenting with posttraumatic neuropathy of the trigeminal nerve

AIMS

To describe the cause, clinical signs, and symptoms of patients presenting to a tertiary care center with iatrogenic lesions to the mandibular branches of the trigeminal nerve.

METHODS

Pain history, pain scores using the visual analog scale, and mechanosensory testing results were recorded from 93 patients with iatrogenic lingual nerve injuries (LNI) and 90 patients with iatrogenic inferior alveolar nerve injuries (IANI). Results were analyzed using the SPSS statistical software. Chi-square tests were applied for nonparametric testing of frequencies, where P ⋜ .05 indicated statistical significance. Appropriate correlations were also carried out between certain data sets.

RESULTS

Significantly more females were referred than males (P < .05). Overall, third molar surgery (TMS) caused 73% of LNI, followed by local anesthesia (LA) (17%). More diverse procedures caused IANI, including TMS (60%), LA (19%), implants (18%), and endodontics (8%). Approximately 70% of patients presented with neuropathic pain coincident with anesthesia and÷or paresthesia. Neuropathy was demonstrable in all patients with varying degrees of loss of mechanosensory function, paresthesia, dysesthesia, allodynia, and hyperalgesia. Functionally, IANI and LNI patients mostly had problems with speech and eating, where speech was affected amongst significantly more patients with LNI (P < .001). Sleep, brushing teeth, and drinking were significantly more problematic for IANI patients (P < .05, P < .001, and P < .0001, respectively).

CONCLUSION

Neuropathic pain, as well as anesthesia, frequently occurs following iatrogenic trigeminal nerve injury similar to other posttraumatic sensory nerve injuries. This must be acknowledged by clinicians as a relatively common problem and informed consent appropriately formulated for patients at risk of trigeminal nerve injuries in relation to dentistry requires revision.