Traumatic Facial and Vestibulocochlear Nerve Injury in The Internal Acoustic Canal in The Absence of A Temporal Bone Fracture

Cranial Nerve Injuries in Orthognathic Surgery: A Review of Literature

ABSTRACT

Orthognathic surgery is increasingly utilized to correct facial deformities and dental malocclusions, as well as to enhance facial aesthetics. Significant advancements in surgical planning and execution have made it more widespread and accessible. However, unfavorable outcomes or complications can occur, leading to potentially severe and possibly long-term consequences, such as cranial nerve injuries. This literature review investigates the cranial nerve complications associated with orthognathic surgery. We conducted an extensive search across available databases, analyzing relevant studies published up to September 30, 2023. Two authors independently selected articles for full-text review based on their titles and abstracts. The eligible studies reported cranial nerve injuries in individuals who had undergone orthognathic surgery. Our findings highlight the risk of cranial nerve injuries, their possible mechanism, management, and outcomes. It is imperative for surgeons to remain vigilant and informed and to communicate such information during preoperative patient consultation.

Brainstem auditory evoked potential combined with high resolution cranial base CT can optimize the diagnosis of auditory nerve injury

PURPOSE

Auditory nerve injury is one of the most common nerve injury complications of skull base fractures. However, there is currently a lack of auxiliary examination methods for its direct diagnosis. The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury.

METHODS

Through retrospectively analyzing the results of brainstem auditory evoked potential (BAEP) and high-resolution CT (HRCT) in 37 patients with hearing impairment following trauma from January 1, 2018 to July 31, 2020, the role of the two inspection methods in the diagnosis of auditory nerve injury was studied. Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma; while exclusion criteria were: (1) severe patient with a Glasgow coma scale score ≤5 because these patients were classified as severe head injury and admitted to the intensive care unit, (2) patient in the subacute stage admitted 72 h after trauma, and (3) patient with prior hearing impairment before trauma. According to Goodman's classification of hearing impairment, the patients were divided into low/medium/severe injury groups. In addition, patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results. The positive rates of BEAP for each group were observed, and the results were analyzed by Chi-square test (p < 0.05, regarded as statistical difference).

RESULTS

A total of 37 patients were included, including 21 males and 16 females. All of them were hospitalized patients with GCS score of 6-15 at the time of admission. The BAEP positive rate in the medium and severe injury group was 100%, which was significantly higher than that in the low injury group (27.27%) (p < 0.01). The rate of BEAP positivity was significantly higher in the HRCT-positive group (20/30, 66.7%) than in the HRCT-negative group (1/7, 14.3%) (p < 0.05). Twenty patients (54.05%) were both positive for BEAP and HRCT test, and considered to have auditory nerve damage. Six patients (16.22%) were both negative for BEAP and HRCT test, and 10 patients (27.03%) were BAEP-negative but HRCT-positive: all the 16 patients were considered as non-neurological injury. The rest 1 case (2.70%) was BAEP-positive but HRCT-negative, which we speculate may have auditory nerve concussion.

CONCLUSION

By way of BAEP combining with skull base HRCT, we may improve the accuracy of the diagnosis of auditory nerve injury. Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.

Cell Transplantation to Restore Lost Auditory Nerve Function is a Realistic Clinical Opportunity

Hearing is one of our most important means of communication. Disabling hearing loss (DHL) is a long-standing, unmet problem in medicine, and in many elderly people, it leads to social isolation, depression, and even dementia. Traditionally, major efforts to cure DHL have focused on hair cells (HCs). However, the auditory nerve is also important because it transmits electrical signals generated by HCs to the brainstem. Its function is critical for the success of cochlear implants as well as for future therapies for HC regeneration. Over the past two decades, cell transplantation has emerged as a promising therapeutic option for restoring lost auditory nerve function, and two independent studies on animal models show that cell transplantation can lead to functional recovery. In this article, we consider the approaches most likely to achieve success in the clinic. We conclude that the structure and biochemical integrity of the auditory nerve is critical and that it is important to preserve the remaining neural scaffold, and in particular the glial scar, for the functional integration of donor cells. To exploit the natural, autologous cell scaffold and to minimize the deleterious effects of surgery, donor cells can be placed relatively easily on the surface of the nerve endoscopically. In this context, the selection of donor cells is a critical issue. Nevertheless, there is now a very realistic possibility for clinical application of cell transplantation for several different types of hearing loss.

Chameleons, red herrings, and false localizing signs in neurocritical care

False localizing signs (FLS) and other misleading neurological signs have long been an intractable aspect of neurocritical care. Because they suggest an incorrect location or etiology of the pathological lesion, they have often led to misdiagnosis and mismanagement of the patient. Here, we reviewed the existing literature to provide an updated, comprehensive descriptive review of these difficult to diagnose signs in neurocritical care. For each sign presented, we discuss the non-false localizing presentation of symptoms, the common FLS or misleading presentation, etiology/pathogenesis of the sign, and diagnosis, as well as any other clinically relevant considerations. Within cranial neuropathies, we cover cranial nerves III, IV, V, VI, VII, VIII, as well as multiple cranial nerve involvement of IX, X, and XII. FLS ophthalmologic symptoms indicate diagnostically challenging neurological deficits, and here we discuss downbeat nystagmus, ping-pong-gaze, one-and-a-half syndrome, and wall-eyed bilateral nuclear ophthalmoplegia (WEBINO). Cranial herniation syndromes are integral to any discussion of FLS and here we cover Kernohan's notch phenomenon, pseudo-Dandy Walker malformation, and uncal herniation. FLS in the spinal cord have also been relatively well documented, but in addition to compressive lesions, we also discuss newer findings in radiculopathy and disc herniation. Finally, pulmonary syndromes may sometimes be overlooked in discussions of neurological signs but are critically important to recognize and manage in neurocritical care, and here we discuss Cheyne-Stokes respiration, cluster breathing, central neurogenic hyperventilation, ataxic breathing, Ondine's curse, and hypercapnia. Though some of these signs may be rare, the framework for diagnosing and treating them must continue to evolve with our growing understanding of their etiology and varied presentations.