Identification of anterior loop in different populations to avoid nerve injury during surgical procedures-a systematic review and meta-analysis

The anterior loop of the inferior alveolar nerve within the mentonian foramen: a scoping review

PURPOSE

The aim of this study is to delineate the safety zone concerning the anteriorization of the AL and correlate it with the behavior of the AL, analyzing its feasibility.

METHODS

Adhering to the Joanna Briggs Institute (JBI) manual guidelines, both the protocol and this review were conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist. MeSH terms, combined with free terms, were utilized to search for articles in the following databases: Embase, LILACS, LIVIVO, PubMed/MEDLINE, Scopus, Web of Science, and grey literature.

RESULTS

Fifteen articles were select following the eligibility criteria. An average safe zone of 4.75 mm in humans was observed, with a prevalence 60.8% and average anterior length of the AL of 2.09 mm in humans.

CONCLUSION

The AL has varied patterns across different populations, then, it could not be asserted a 100% safe zone. Preoperative analysis of the AL with CBCT is always necessary. While it could be stated that a safe zone should be employed as an inviolable region, stipulated measures of a safe zone should be regarded as an area of greater attention in preoperative planning.

Three-dimensional analysis of mandibular and mental canals corroborating with teeth and mental foramen by cone beam computed tomography

BACKGROUND

This study aimed to analyse the 3D patterns of the mandibular and mental canals (MDC and MC) referring to the surrounding prominent surgical landmarks such as teeth and mental foramen by cone beam computed tomography (CBCT).

METHODS

CBCT scans of 354 patients aged 18-67 years with mandibular first premolar to second molar were included and reconstructed 3-dimensionally (3D) by mimics. The parameters of MDC and MC were measured referring to teeth and mental foramen.

RESULTS

From the first premolars to the second molars, the mandibular canals showed a trend of gradually closer to the cementoenamel junction (CEJ) of the adjacent teeth and farther away from the buccal cortical plate. The distance of the MDC with the root apexes (RA) was relatively constant from the first premolar to the first molar, but became much closer to the second molar. About 10.8% of the second molars had MDC-RA distances of shorter than 2 mm, and 1.34% even had the MDC superior to the RA. Moreover, the Type III of MC presented in 66.0% of the subjects and had a relatively longer length. Besides, the existence of Type I MC may be related to the MDC featuring with close distances to the RA and CEJ of the adjacent teeth.

CONCLUSION

Dentists and surgeons should know the patterns of mandibular and mental canals. A better understanding of the MDC and MC and their relationship to local anatomical landmarks may facilitate the planning of surgeries and alert potential nerve injuries in the operative procedures.

Automated segmentation of the mandibular canal and its anterior loop by deep learning

Accurate mandibular canal (MC) detection is crucial to avoid nerve injury during surgical procedures. Moreover, the anatomic complexity of the interforaminal region requires a precise delineation of anatomical variations such as the anterior loop (AL). Therefore, CBCT-based presurgical planning is recommended, even though anatomical variations and lack of MC cortication make canal delineation challenging. To overcome these limitations, artificial intelligence (AI) may aid presurgical MC delineation. In the present study, we aim to train and validate an AI-driven tool capable of performing accurate segmentation of the MC even in the presence of anatomical variation such as AL. Results achieved high accuracy metrics, with 0.997 of global accuracy for both MC with and without AL. The anterior and middle sections of the MC, where most surgical interventions are performed, presented the most accurate segmentation compared to the posterior section. The AI-driven tool provided accurate segmentation of the mandibular canal, even in the presence of anatomical variation such as an anterior loop. Thus, the presently validated dedicated AI tool may aid clinicians in automating the segmentation of neurovascular canals and their anatomical variations. It may significantly contribute to presurgical planning for dental implant placement, especially in the interforaminal region.

Posttraumatic Trigeminal Neuropathic Pain in Association with Dental Implant Surgery

Posttraumatic trigeminal neuropathy in association with dental implant surgery is preventable, and this should be the emphasis for all clinicians considering this treatment for a patient. Once the nerve injury and posttraumatic neuropathy with or without pain ensues, there is very little the clinician can do to reverse it and the high pain and permanency of the neuropathy will have a significant functional and psychological impact on the patient. Immediate implant removal is required, and home check should be routine for all cases. International diagnostic criteria are available and should be implemented in everyday practice.

Bifid Mandibular Canal: A Proportional Meta-Analysis of Computed Tomography Studies

Introduction

Growing body of evidences showed different grades in prevalence of bifid mandibular canals. Because the previous reviews focused solely on patient-level occurrence, hemi-mandible-level prevalence, bilateral symmetry, length, and diameter of bifid mandibular canals were required to be estimated collectively. The research question of this meta-analysis was "What is the prevalence of bifid mandibular canal among patients seeking computed tomography examinations"?

Materials and Methods

In vivo, computed tomography, and cross-sectional studies were eligible. Studies, with less than 100 subjects or anatomic site restriction or controlled class of bifid mandibular canal, were excluded. Joanna Briggs Institute (JBI) critical appraisal tool for prevalence studies was used to assess methodological quality of all included studies. Random effect meta-analyses for proportion of bifid mandibular canal were done.

Results

40 studies met the inclusion criteria. All studies were selected for both systematic review and meta-analyses. Totally, 17714 patients and 31973 hemi-mandibles were included. All eligible studies showed moderate risk of bias on average. Resulting from the random effect model, more than 20% of patients seeking computed tomographic examinations had bifid mandibular canals (BMCs) which penetrated into slightly more than 14% of hemi-mandibles. Of the patients having bifid mandibular canals (BMCs), nearly 23% exhibited such anatomy on both sides of their mandibles. Estimated mean length and diameter of the accessory canals of bifid mandibular canals were 12.17 mm and 1.54 mm, respectively.

Conclusion

The geographical locations, classifications, reliability test, and voxel size of computed tomography were all implicated in the prevalence of bifid mandibular canals along with gender and laterality, although considerable heterogeneity and bias were detected.

Prevalence and extension of the anterior loop of the mental nerve in different populations and CBCT imaging settings: A systematic review and meta-analysis

Purpose

Materials and Methods

Results

Conclusion

Assessment of Anterior Loop of Inferior Alveolar Nerve and Its Anatomic Variations with Age, Gender, and Dentition Status in Indian Population: A CBCT Study

Background

The posterior region of the mandible is more often related to iatrogenic errors, but the interforaminal region is also not spared for neurovascular complications. This study aimed to use CBCT images to evaluate the prevalence of anterior nerve looping and its variations with age, gender, and dentition status.

Methods

This retrospective study was carried out by studying 600 CBCT scans retrieved from archival records of a CBCT center in Lucknow. The scans were inspected by two trained investigators. The length of the anterior loop was measured using the measuring tool of Carestream 3D imaging software. Descriptive and analytical tests were performed.

Results

The prevalence of the anterior loop of the inferior alveolar nerve was found to be 56%. The prevalence was found to be more on the right side (29.0%) compared to the left side (27.0%). The most common anterior looping of the inferior alveolar nerve was type 3 followed by type 1. Males were found to have significantly higher loops compared to females. The number of loops was found to decrease significantly with age. The mean length of the loop was found to vary from 1.14 to 1.61 mm.

Conclusion

The anterior looping of IAN is very much prevalent in the Lucknow population. The use of the CBCT technique and appropriate preplanning prior to surgery or implant placement should be performed to prevent nerve injury.