ABSTRACT
High grade gliomas are always the research focus in the field of neurosurgery due to their poor prognosis despite the current standard therapeutic regimen of surgical resection followed by radiation therapy and chemotherapy.Alkylating agent temozolomide has been established as the standard chemotherapy while its resistance inevitable during treatment.This phenomenon seriously influences the prognosis of patients suffering from high grade gliomas.This review aims to elucidate temozolomide chemoresistance mechanisms through three chapters including O6-methylguanine-DNA methyltransferase (MGMT) methylation,mismatch repair mutation and epigenetic regulation consisting of p21,chromatin and histone,Y-box binding protein-1 and microRNAs.
ABSTRACT
<p><b>PURPOSE</b>Posterior fossa epidural hematomas (PFEDH) are uncommon in children but usually require timely surgical intervention due to the risk of life-threatening brainstem compression. We attempt to make the surgical procedure less invasive by treating selected pediatric patients with trephination mini-craniectomy.</p><p><b>METHODS</b>We retrospectively reviewed the clinical courses, radiological findings, surgical procedures, and prognoses of the pediatric patients who were treated in our departments for traumatic PFEDH from January 2010 to January 2015.</p><p><b>RESULTS</b>During this period, a total of 17 patients were surgically treated for PFEDH and 7 were managed with trephination mini-craniectomy for hematoma evacuation. The outcomes were good in all 7 patients as evaluated with Glasgow Outcome Score. There was no mortality in this series. The on average 30-month clinical follow-up showed that patients experienced satisfactory recoveries without complications.</p><p><b>CONCLUSION</b>Our results suggest that trephination mini-craniectomy is a safe surgical technique for selected PFEDH patients with moderate hematoma volume and stabilized neurological functions. However, standard craniectomy is recommend when there are rapid deteriorations in patients' neurological functions or the hematomas are large and exerted severe mass effects.</p>