Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

OBJECTIVE: The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. METHODS: A total of 16 patients with large skull defects (>100 cm2) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. RESULTS: The median operation time was 184.36+/-26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. CONCLUSION: Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.

Sudden Unilateral Blindness and Ophthalmoplegia after Ruptured Anterior Communicating Artery Aneurysm Surgery: Report of 2 Cases / 대한뇌혈관외과학회지

The incidence of unilateral blindness and ophthalmoplegia after aneurysm surgery is very rare, especially in an anterior communicating artery (ACoA) aneurysm, but if it occurs, it is mainly caused by intra-operative nerve injury or retinal ischemia. We experienced 2 cases of unilateral blindness immediately after surgery. Both patients were classified into Hunt-Hess grade 1 and Fisher grade 3. Angiographic findings of these patients revealed that the aneurysms were located at the left ACoA. The aneurysms were clipped easily with minimal brain retraction via standard pterional craniotomy. In both cases, injury of the optic nerve during surgery was unlikely. Both patients complained of visual loss with ophthalmoplegia ipsilateral to the site of surgery on the 1st postoperative day and showed evidence of retinal ischemia with central retinal artery occlusion on fundoscopic examination. In our patients, we hypothesize that the complications were most likely related to the intra-orbital ischemia initiated by the collapse of the arterial and venous channels in the orbit and/or to the direct or indirect contusion on the intra-orbital structures. These situations could be produced by inadvertent pressure placed on the eyeball with a bulky retracted frontal skin flap. Visual acuity in both patients ranged from no light perception to finger-counting. Their external ophthalmoplegia had completely disappeared 2 weeks after surgery and visual acuity in one patient began to improve. But in the other patient, the condition was irreversible. The degree of visual recovery seems to be dependent on the duration and severity of retinal ischemia by orbital compression. Unfortunately, there is no satisfactory treatment. We recommend careful surgical manipulation, including the use of an eye shield just before aneurysm surgery to protect the ipsilateral eyeball.

Early Postoperative Cerebral Angiography After Clipping in Patients with Ruptured Aneurysm: its Usefulness and Indications / 대한뇌혈관외과학회지

OBJECTIVE: The objective of this study was to determine whether postoperative conventional angiography conducted during the early stage after aneurysm clipping is useful in patients with ruptured aneurysm. METHODS: Between May 2008 and November 2009, 57 patients who presented with ruptured cerebral aneurysms were treated with surgical clipping. Among them, a consecutive series of 45 patients who underwent postoperative angiography was analyzed retrospectively. Parameters of the postoperative angiography were categorized as incomplete clippings, vasospasms, vascular compromises, or other aneurysms. RESULTS: The average age of the patients was 49.2 years and ranged from 18 to 72 years. The average timing of the postoperative angiography after the onset of hemorrhage was 11.1 (+/- 5.6) days. Complete aneurysm closure was achieved in 43 (95%) patients. A neck remnant aneurysm was discovered in two patients and a fundus remnant was revealed in one patient. Twelve (27%) patients showed angiographic vasospasms and seven needed angioplasty. Four cases (9%) revealed either parent artery stenosis or branch occlusions, and two of them (4%) were clinically significant. Two cases showed aneurysms at another location, one of which was a ruptured aneurysm. Overall, 21 (47%) patients exhibited significant findings on the postoperative angiography. CONCLUSIONS: Our retrospective analysis revealed that postoperative angiography might be valuable in patients with ruptured aneurysms, especially in the acute stage, in order to determine the presence of vasospasms, incomplete clippings, vascular compromises, or other aneurysms that were missed at the initial cerebral angiography.

Hypoxia induces Wee1 expression and attenuates hydrogen peroxide-induced endothelial damage in MS1 cells

In an oxygen-depleted environment, endothelial cells initiate an adaptive pattern of synthesis, which may enable them to survive hypoxic crises. Using high-resolution two-dimensional gel electrophoresis in conjunction with mass spectroscopy, we obtained a 24 differential display of proteins in the pancreatic endothelial cell line, MS-1, at four time points following induction of hypoxia. The induction of Wee1 under hypoxia was confirmed both at the mRNA and protein levels. The phosphorylation of cell division cycle 2, which is downstream of Wee1, was also increased after hypoxic exposure. In addition, pre-exposure to hypoxia attenuated a decrease in hydrogen peroxide-induced cell number. The induction of bax (a pro-apoptotic protein) and reduction of bcl (an anti-apoptotic protein) after hypoxia stimulus were also attenuated by hypoxic pre-exposure. Moreover, hydrogen peroxide-induced morphologic damage did not appear in the wild-type Wee1-expressing cells. Taken together, our results suggest that Wee1 may have important role in hypoxia-induced pathophysiological situations in endothelial cells.

Clinical Analysis of Patients with Spontaneous Subarachnoid Hemorrhage of Initial Negative Angiography / 대한뇌혈관외과학회지

OBJECTIVE: The purpose of this study was to reveal the incidence of subarachnoid hemorrhage (SAH) of initial negative angiography and to find a useful method of follow up angiography through retrospective review. Additional objective was to determine the relationship between the hidden aneurysm and initial Computed Tomography (CT) pattern (i.e. amount and distribution of SAH). METHODS: Among 593 cases of spontaneous SAH performed initial cerebral angiography, 83 (12%) patients did not show any identifiable vascular lesions in initial angiographic studies. Repeated angiographic studies were performed in 67 patients by using transfemoral catheter angiography (TFCA) in 26 patients, CT angiography (CTA) in 39 and Magnetic Resornance (MR) angiography in 2. RESULTS: Ten (15%) out of 67 patients who underwent repeated angiography revealed aneurysms. At the comparison of initial CT scan and repeated angiography, 31 patients had thick layer of blood and 25% of these patients revealed aneurysms on repeated angiography (P=0.05). According to the initial CT pattern, 38 patients had diffuse blood distribution and 23% of these patients revealed aneurysms on repeated angiography (P=0.05). The timing of follow up angiography was 8.5 +/- 6.0 days (mean +/- SD) after ictus and CTA was applied in the earlier period than TFCA. CONCLUSIONS: If initial CT scans show thick layer of SAH or diffuse type of blood distribution in patients with initial negative angiography, repeated angiographic study should be performed to find hidden vascular lesions. CT angiography might be useful in the detection of hidden aneurysm early in the course.

Clinical Analysis of Patients with Spontaneous Subarachnoid Hemorrhage of Initial Negative Angiography / 대한뇌혈관외과학회지

OBJECTIVE: The purpose of this study was to reveal the incidence of subarachnoid hemorrhage (SAH) of initial negative angiography and to find a useful method of follow up angiography through retrospective review. Additional objective was to determine the relationship between the hidden aneurysm and initial Computed Tomography (CT) pattern (i.e. amount and distribution of SAH). METHODS: Among 593 cases of spontaneous SAH performed initial cerebral angiography, 83 (12%) patients did not show any identifiable vascular lesions in initial angiographic studies. Repeated angiographic studies were performed in 67 patients by using transfemoral catheter angiography (TFCA) in 26 patients, CT angiography (CTA) in 39 and Magnetic Resornance (MR) angiography in 2. RESULTS: Ten (15%) out of 67 patients who underwent repeated angiography revealed aneurysms. At the comparison of initial CT scan and repeated angiography, 31 patients had thick layer of blood and 25% of these patients revealed aneurysms on repeated angiography (P=0.05). According to the initial CT pattern, 38 patients had diffuse blood distribution and 23% of these patients revealed aneurysms on repeated angiography (P=0.05). The timing of follow up angiography was 8.5 +/- 6.0 days (mean +/- SD) after ictus and CTA was applied in the earlier period than TFCA. CONCLUSIONS: If initial CT scans show thick layer of SAH or diffuse type of blood distribution in patients with initial negative angiography, repeated angiographic study should be performed to find hidden vascular lesions. CT angiography might be useful in the detection of hidden aneurysm early in the course.

Delayed Progressive Extradural Pneumatocele due to Incomplete Sealing of Opened Mastoid Air Cell after Micro-Vascular Decompression

A case of delayed progressive extradural pneumatocele after microvascular decompression (MVD) is presented. A 60-year-old male underwent MVD for hemifacial spasm; the mastoid air cell was opened and sealed with bone wax during surgery. One month after surgery, the patient complained of tinnitus, and progressive extradural pneumatoceles without cerebrospinal fluid (CSF) leakage was observed. Revision surgery was performed and the opened mastoid air cell was completely sealed with muscle patch and glue. The patient's symptoms were resolved, with no recurrence of pneumatoceles at 6 month follow up. Progressive extradural pneumatocele without CSF leakage after posterior fossa surgery is a very rare complication. Previous reports and surgical management of this rare complication are discussed.

Primary Central Nervous System Lymphoma in Organ Recipient

We report a case of primary central nervous system(CNS) lymphoma in an organ recipient. A 33-years-old man who underwent a renal transplantation 3years previously presented with headache and vomiting. In Brain computed tomography scans and magnetic resonance images showed multiple periventricular cystic rim enhancing masses. Pathologic diagnosis by stereotactic biopsy revealed malignant non-Hodgkins B-cell lymphoma. After pathologic confirmation, methotrexate chemotherapy and whole brain radiation therapy were done. Having experienced such a case, the authors strongly recommend to add primary CNS lymphoma as one of the differential diagnoses to brain abscess, metastatic brain tumor and glioblastoma multiforme in cases of multiple ring enhancing periventricular lesions of immunocompromised patient or organ recipient.

Cranioplasty with the Porous Polyethylene Implant(Medpor) for Large Cranial Defect

OBJECTIVE: This paper describes our experience and implant technique for cranioplasty of a large cranial defects using a porous polyethylene implant(Medpor) and compares the results with polymethylmethacrylate(PMMA). METHODS: Sixteen cranioplasties were performed using Medpor(n=10) and PMMA(n=6) implants between June 2003 and January 2005. The criterion for patient enrollment was a defect larger than 10cm in diameter. This study compared the operation times and complications. RESULTS: The operation times ranged from 105 to 250minutes(Mean 180 degrees +/-44minutes) in Medpor and from 185 to 460minutes (mean 128minutes) in PMMA. The absolute operation times were shorter using the Medpor implant and the differences were statistically significant(P=0.030). Satisfactory cosmetic results were obtained in all cases using the Medpor implant and with no implant-related complications. Bone ingrowth to the medpor implant was presumed to be the result on an increase in Houndsfield units of the implant, particularly at the marginal areas in the serial follow-up brain computed tomography images. CONCLUSION: It is believed that the properties of a Medpor implant make this implant an good alternative to the existing methods of a cranial contour correction. However, a further follow-up study will be needed.