Exogenous nerve growth factor protects the hypoglossal nerve against crush injury

Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase（MAPK）pathway,but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear.Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury,but there has been little research focusing on the hypoglossal nerve injury and repair.In this study,we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days.p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury;exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus.Under transmission electron microscopy,we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury.Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury.

Predictors of success in hypoglossal nerve stimulator implantation for obstructive sleep apnea

Objective:Current guidelines for hypoglossal nerve stimulator(HGNS)implantation eligibility include drug-induced sleep endoscopy(DISE)findings and other patient characteristics but lead to highly variable rates of surgical success across institutions.Our objective was to determine whether additional factors seen on preoperative evaluation could be used as predictors of surgical success.Study design:Retrospective chart review.Setting:Single-institution academic tertiary care medical center.Subjects:and Methods:This study included patients with obstructive sleep apnea(OSA)who underwent HGNS implantation between 2015 and 2018.Surgical success was defined as a post-operative apnea-hypopnea index(AHI)of less than 20 events per hour and an AHI reduction of at least 50%.Preoperative polysomnogram(PSG)results,DISE findings,and physical parameters were compared between surgical successes and failures.Results:A total of 68 patients were included in the analysis.The overall surgical success rate was 79.4%(54/68).Elevated preoperative AHI was associated with an increased likelihood of treatment failure,with an AHI of(36.9±16.8)events/hour in the success group compared to(49.4±19.6)events/hour in the failure group(P=0.05).Patients observed to have partial lateral oropharyngeal collapse on DISE was more frequently associated with the treatment failure group than in the success group(P=0.04).Conclusion:Patients who underwent HGNS implantation overall had a very high treatment response rate at our institution.Factors that may predispose patients to surgical failure included the presence of lateral oropharyngeal collapse and a significantly elevated preoperative AHI.These should be considered when determining surgical candidacy for HGNS implantation.

Case Report of Combined Sixth and Twelfth Cranial Nerve Palsy: A Rare Case of Clival Syndrome Arising from Thymoma

Godtfredsen syndrome or clival syndrome is a rare syndrome of abducens and hypoglossal nerve palsies (cranial nerve 6th and 12th respectively) that localizes to a clival mass. There are few reported cases of this clinical presentation. The aim of this case report is to describe this rare manifestation observed in a woman with clival metastases arising from a thymoma. A previously well 34-year-old native lady presented to a district hospital in Sabah, Malaysia, with history of blurring of vision and headache for 1 month. Cranial nerve examination reveals right abducens nerve palsy (right 6th CN) and right hypoglossal nerve palsy (right 12th CN). Initial imaging with CT brain reveals a subtle extra-axial hyperdense mass adjacent to the clivus and a routine chest x-ray reveals a mediastinal mass. Further imaging of thorax showed right anterior mediastinal mass, which then proceeded with Video-Assisted Thoracoscopic Surgery (VATS) guided biopsy. The biopsy result was consistent with the finding of thymoma, type B2. She was then diagnosed with aggressive form of thymoma, which unfortunately has metastasized to the bone, lung, liver and brain. Despite prognosis at the time of diagnosis is guarded, she still opted to undergo chemotherapy. Despite the completion of 6 cycles of chemotherapy, her disease progressed, and she eventually succumbed to the illness. In short, the presence of combined 6th and 12th palsy should alert clinician to the possibility of clival mass or metastases and hence could earlier workup with appropriate imaging can lead to earlier diagnosis and better treatment outcome.