The Onyx liquid embolic system is a relatively safe and commonly used treatment for vascular malformations, such as arteriovenous fistulas and arteriovenous malformations. However, studies on possible complications after Onyx embolization in patients with vascular malformations are limited, and the occurrence of cranial nerve palsy is occasionally reported. Here we report the progress of two different types of cranial nerve palsy that can occur after embolization. In both cases, Onyx embolization was performed to treat vascular malformations and ipsilateral oculomotor and facial nerve palsies were observed. Both patients were treated with steroids and exhibited symptom improvement after several months. The most common types of neuropathy that can occur after Onyx embolization are facial nerve palsy and trigeminal neuralgia. Although the mechanisms underlying these neuropathies are not clear, they may involve traction injuries sustained while extracting the microcatheter, mass effects resulting from thrombi and edema, or Onyx reflux into the vasa nervorum. In most cases, the neuropathy spontaneously resolves several months following the procedure.

ObjectiveSubdural effusion, also known as subdural hygroma (SDG), is a secondary complication that can occur after decompressive craniectomy (DC). However, the pathogenesis of SDG is not fully understood. It is unclear whether SDG occurrence is related to preoperative patient status or surgical technique. The purpose of this study is to identify risk factors for SDG after DC.MethodsFifty-nine patients who underwent DC from January 2016 to December 2016 at the same institution were analyzed. We retrospectively reviewed the clinical and radiological features of the patients. We divided the patients into two groups based on the occurrence of SDG after DC. The risk factors for SDG were analyzed.ResultsThe overall SDG rate after DC was 39% (23 patients). A statistically significant association was observed between preoperative diagnosis, e.g., subdural hemorrhage (SDH; odds ratio [OR], 4.99; 95% confidence interval [CI], 1.36–18.34) or subarachnoid hemorrhage (SAH; OR, 4.18; 95% CI, 1.07–16.32), and the occurrence of SDG after DC. Traumatic brain injury (OR, 4.91; 95% CI, 1.35–17.91) and preoperative cortical opening (OR, 4.77; 95% CI, 1.39–16.32) were important risk factors for SDG. Several surgical techniques did not show a statistically significant association with SDG. The occurrence of SDG after DC was related to the length of hospital stay (p=0.012), but not to prognosis.ConclusionAfter DC, SDG is not related to patients' prognosis but to the length of hospital stay. Therefore, it is necessary to study the occurrence of postoperative SDG by confirming the presence of preoperative SDH, SAH, and cortical opening.

ObjectiveAfter a rigorous management of increased intracranial pressure by decompressive craniectomy (DC), cranioplasty (CP) is usually carried out for functional and cosmetic purposes. However, the optimal timing of CP remains controversial. Our study aims to analyze the relationship between the optimal timing of CP and the post-operative complications.MethodsFrom January 2013 to December 2015, ninety patients who underwent CP in a single institution were analyzed. We set the independent variables as follows: 1) patient characteristics; 2) the time interval between the DC and CP; 3) operation time; 4) anesthesia time; and 5) pre-operative computed tomography (CT) findings such as a degree of sunken brain by ratio of A (the median length from scalp to midline) to B (the length from midline to inner table of skull at this level). The dependent variables of this study are the event of post-operative complications.ResultsThe overall complication rate was 33.3%. There was no statistical significance in the time interval between the DC and CP in the groups with and without complications of CP (p=0.632). However, there was a significant statistical difference in the degree of sunken brain by ratio (A/B) between the two groups (p<0.001).ConclusionFrom this study, we conclude that it is better to determine the optimal timing of CP by the pre-operative CT finding than by the time interval between the DC and CP. Hereby, we suggest a potentially useful determinant of optimal timing of CP.