Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_892_Библиотеки_им_академика_М_И_Перельмана

Sensory innervation of the face is provided by three branches of the trigeminal nerve: the ophthalmic, maxillary, and mandibular nerves. The inferior alveolar (IAN) and lingual nerves (LN) are the most commonly injured peripheral nerves during oral and maxillofacial surgery. Among oral treatments, molar tooth extrac­tions are very common, and up to 10 million third molars are extracted at an annual cost of over 3 billion dollars. Tooth extractions alone account for 60% of all nerve injuries in the jaw, with an incidence of permanent paresthesia and functional dis­ability in the lip, tongue, and cheek ranging from 11,500 to 35,000 [4]. The Seddon and Sunderland grading systems have traditionally been used in classifying nerve injuries. Seddon etal. categorized nerve injuries based on severity into neurapraxia, axonotmesis, and neurotmesis. Pathologic changes in neurapraxia, the mildest type of injury, involve only the myelin sheath around the axon and are associated with an excellent prognosis. In axonotmesis, the axon suffers complete rupture resulting in Wallerian degeneration of its distal segment. However, the supporting structures, including the perineurium and epineurium, remain intact. The prognosis for recov­ery remains good, but time is required for axonal regeneration (approximately 1mm per day). Neurotmesis is the most severe type of injury and refers to the complete severance of the nerve. The result is total functional loss, and unless early surgical intervention is performed, clinical recovery is not anticipated. In 1951, Sunderland further stratied the classication proposed by Seddon into the individual structures of organized nerve tissue: myelin loss, axonal loss, and endoneurial, perineurial, and epineurial injury. Despite advancements in understanding nerve injuries and microsurgical techniques and materials, the current diagnostic strategy of using NST and existing classication systems is limited. Zuniga etal. hypothesized that MR neurography could be reliably used to diagnose and classify injuries to the peripheral trigeminal nerve and performed multiple studies investigating whether MRN of peripheral trigeminal neuropathies (PTNs) could serve as a diagnostic modality by correlating NST, MRN, and surgical ndings. A 2017 study by Zuniga etal. examined 60 patients with traumatic and nontraumatic peripheral trigeminal neuropathies of varying etiologies and Sunderland classications who had under­gone MRN evaluation, in addition to clinical NST and, in some cases, trigeminal nerve surgery. To test the hypothesis, two groups of patients were examined. The rst were those who had a known traumatic injury of the trigeminal nerve, and the second were those without a known traumatic injury. The traumatic injuries included third molar extraction, dental implantation, mandibular surgery, and orthognathic surgery. The nontraumatic injuries included three categories of etiologies: dental injection, noninvasive endodontic treatment, and unknown sensory complaints. Patients underwent MRN imaging using 1.5T and 3.0T scanners, including two­dimensional and three-dimensional imaging, and two musculoskeletal radiologists read MRN ndings of nerve signal and caliber alteration. A Sunderland classica­tion was then given by the radiologists unaware of the NST grading using the