Sang Dae Kim

Development and Growth of the Normal Cranial Vault : An Embryologic Review

Understanding the development of a skull deformity requires an understanding of the normal morphogenesis of the cranium. Craniosynostosis is the premature, pathologic ossification of one or more cranial sutures leading to skull deformities. A review of the English medical literature using textbooks and standard search engines was performed to gather information about the prenatal development and growth of the cranial vault of the neurocranium. A process of morphogenic sequencing begins during prenatal development and growth, continues postnatally, and contributes to the basis for the differential manner of growth of cranial vault bones. This improved knowledge might facilitate comprehension of the pathophysiology of craniosynostosis.

Comparison of subgroups based on hemorrhagic lesions between SWI and FLAIR in pediatric traumatic brain injury

PurposeThe purpose of this study was to investigate efficient ways to diagnose and predict clinical outcomes for childhood traumatic brain injury.MethodsHemorrhagic signal intensities in nine brain regions were observed using axial fluid-attenuated inversion recovery (FLAIR) and susceptibility-weighted imaging (SWI). After having divided the subjects into mild presentation (GCS 14–15) and moderate-to-severe presentation groups (GCS ≤13), we divided the patients into three subgroups: Subgroup I, hemorrhagic foci observed only on SWI and not on FLAIR; Subgroup II, hemorrhagic foci observed on both SWI and FLAIR in the same brain regions; and Subgroup III, any cases with additional foci on SWI in other brain regions. We investigated the clinical course and compared lesion numbers and distributions of hemorrhagic lesions on SWI among the subgroups.ResultsThree clinical variables (hospitalization period in intensive care unit, total days of hospitalization, and outcome based on Pediatric Cerebral Performance Category Scale score) showed significant relevance to the three subgroups. Subgroup I showed the fewest lesions followed by Subgroups II and III, respectively. In all three subgroups, lesions were most abundant in cortical regions. Lesion in the thalamus, basal ganglia, corpus callosum, and brainstem was least in Subgroup I and gradually increased in Subgroups II and III. Such distinction was more significant in the moderate-to-severe group when compared with the mild group.ConclusionsIn cases of pediatric traumatic brain injury, categorizing patients into one of the above three subgroups based on hemorrhagic lesions on SWI and FLAIR is a promising method for predicting patient’s clinical outcome.

Is Routine Repeated Head CT Necessary for All Pediatric Traumatic Brain Injury

Objective Repeated computed tomography (CT) follow up for traumatic brain injury (TBI) patients is often performed. But there is debate the indication for repeated CT scans, especially in pediatric patients. Purpose of our study is to find risk factors of progression on repeated CT and delayed surgical intervention based on the repeated head CT. Methods Between March, 2007 and December, 2013, 269 pediatric patients (age 0-18 years) had admitted to our hospital for head trauma. Patients were classified into 8 subgroups according to mechanisms of injury. Types, amount of hemorrhage and amount changes on repeated CT were analyzed as well as initial Glasgow Coma Scale (GCS) scores. Results Within our cohort of 269 patients, 174 patients received repeat CT. There were progression in the amount of hemorrhage in 48 (27.6%) patients. Among various hemorrhage types, epidural hemorrhage (EDH) more than 10 cc measured in initial CT was found to be at risk of delayed surgical intervention significantly after routine repeated CT with or without neurological deterioration than other types of hemorrhage. Based on initial GCS, severe head trauma group (GCS 3-8) was at risk of delayed surgical intervention after routine repeated CT without change of clinical neurologic status. Conclusion We suggest that the patients with EDH more than 10 cc or GCS below 9 should receive repeated head CT even though absence of significant clinical deterioration.

Single-Stage Transpedicular Vertebrectomy and Expandable Cage Placement for Treatment of Unstable Mid and Lower Lumbar Burst Fractures.

Study Design: Retrospective clinical and radiographic study. Objective: To examine the efficacy and safety of vertebrectomy and expandable cage placement by a single-stage posterior approach for unstable mid and lower lumbar burst fractures (below the L3). Summary of Background Data: Patients with unstable mid and lower lumbar burst fractures require surgical treatment to relieve pain, address paralysis, and stabilize the spine to prevent further segmental deformity. However, controversy remains regarding the optimal surgical treatment. Materials and Methods: Eleven patients underwent single-stage posterior-only vertebral column resection and vertebral body reconstruction using an expandable cage. Neurological status was classified using the American Spinal Injury Association (ASIA) Impairment Scale, whereas functional outcome was analyzed using a visual analog scale for back pain. Segmental Cobb angles were measured above and below the fractured vertebral body preoperatively, immediate postoperatively, and at the last follow-up. Results: The preoperative neurological status was ASIA grade E in 2 patients, grade D in 5 patients, grade C in 2 patients, and grade B in 2 patients. Postoperatively, neurological stability was demonstrated in 3 patients (27%), and 8 (73%) showed improvement in the ASIA grade. The mean preoperative visual analog scale score was 8.3, which decreased to 4.5 postoperatively, and to 1.8 at the final follow-up. The mean preoperative segmental lordotic angle was 9.2 degrees, which increased to 16.9 degrees postoperatively, and decreased to 15.1 degrees at the last follow-up. The mean operating time was 208.8 minutes, and the mean blood loss was 1006.3 mL. Regarding surgical complications, 1 patient experienced a dural tear and 1 patient demonstrated cage subsidence. Conclusions: The results of this small series suggest the feasibility, efficacy, and safety of this surgical option for unstable mid and lower lumbar burst fractures. This technique from a single posterior approach offers several advantages over traditional anterior or combined approaches using strut graft or nonexpandable implants.

Semi-Quantitative Analyses of Hippocampal Heat Shock Protein-70 Expression Based on the Duration of Ischemia and the Volume of Cerebral Infarction in Mice

Objective We investigated the expression of hippocampal heat shock protein 70 (HSP-70) infarction volume after different durations of experimental ischemic stroke in mice. Methods Focal cerebral ischemia was induced in mice by occluding the middle cerebral artery with the modified intraluminal filament technique. Twenty-four hours after ischemia induction, both hippocampi were extracted for HSP-70 protein analyses. Slices from each hemisphere were stained with 2,3,5-triphenyltetrazolium chloride (2%), and infarction volumes were calculated. HSP-70 levels were evaluated using western blot and enzyme-linked immunosorbent assay (ELISA). HSP-70 subtype (hsp70.1, hspa1a, hspa1b) mRNA levels in the hippocampus were measured using reverse transcription-polymerase chain reaction (RT-PCR). Results Cerebral infarctions were found ipsilateral to the occlusion in 10 mice exposed to transient ischemia (5 each in the 30-min and 60-min occlusion groups), whereas no focal infarctions were noted in any of the sham mice. The average infarct volumes of the 2 ischemic groups were 22.28±7.31 mm3 [30-min group±standard deviation (SD)] and 38.06±9.53 mm3 (60-min group±SD). Western blot analyses and ELISA showed that HSP-70 in hippocampal tissues increased in the infarction groups than in the sham group. However, differences in HSP-70 levels between the 2 infarction groups were statistically insignificant. Moreover, RT-PCR results demonstrated no relationship between the mRNA expression of HSP-70 subtypes and occlusion time or infarction volume. Conclusion Our results indicated no significant difference in HSP-70 expression between the 30- and 60-min occlusion groups despite the statistical difference in infarction volumes. Furthermore, HSP-70 subtype mRNA expression was independent of both occlusion duration and cerebral infarction volume.

Closure of Myelomeningocele Defects Using a Limberg Flap or Direct Repair

Background The global prevalence of myelomeningocele has been reported to be 0.8–1 per 1,000 live births. Early closure of the defect is considered to be the standard of care. Various surgical methods have been reported, such as primary skin closure, local skin flaps, musculocutaneous flaps, and skin grafts. The aim of this study was to describe the clinical characteristics of myelomeningocele defects and present the surgical outcomes of recent cases of myelomeningocele at our institution. Methods Patients who underwent surgical closure of myelomeningocele at our institution from January 2004 to December 2013 were included in this study. A retrospective chart review of their medical records was performed, and comorbidities, defect size, location, surgical procedures, complications, and the final results were analyzed. Results A total of 14 patients underwent surgical closure for myelomeningocele defects. Twelve cases were closed with direct skin repair, while two cases required local skin flaps to cover the skin defects. Three cases of infection occurred, requiring incision and either drainage or removal of allogenic materials. One case of partial flap necrosis occurred, requiring secondary revision using a rotational flap and a full-thickness skin graft. Despite these complications, all wounds eventually healed completely. Conclusions Most myelomeningocele defects can be managed by direct skin repair alone. In cases of large defects, in which direct repair is not possible, local flaps may be used to cover the defect. Complications such as wound dehiscence and partial flap necrosis occurred in this study; however, all such complications were successfully managed with simple ancillary procedures.

The Potential of Diffusion-Weighted Magnetic Resonance Imaging for Predicting the Outcomes of Chronic Subdural Hematomas

Objective Diffusion-weighted magnetic resonance imaging (DW-MRI) has proven useful in the study of the natural history of ischemic stroke. However, the potential of DW-MRI for the evaluation of chronic subdural hematoma (CSDH) has not been established. In this study, we investigated DW-MRI findings of CSDH and evaluated the impact of the image findings on postoperative outcomes of CSDH. Methods We studied 131 CSDH patients who had undergone single burr hole drainage surgery. The images of the subdural hematomas on preoperative DW-MRI and computed tomography (CT) were divided into three groups based on their signal intensity and density: 1) homogeneous (iso or low) density on CT and homogeneous low signal intensity on DW-MRI; 2) homogeneous (iso or low) density on CT and mixed signal intensity on DW-MRI; and 3) heterogeneous density on CT and mixed signal intensity on DW-MRI. On the basis of postoperative CT, we also divided the patients into 3 groups of surgical outcomes according to residual hematoma and mass effect. Results Analysis showed statistically significant differences in surgical (A to B: p<0.001, A to C: p<0.001, B to C: p=0.129) and functional (A to B: p=0.039, A to C: p<0.001, B to C: p=0.108) outcomes and treatment failure rates (A to B: p=0.037, A to C: p=0.03, B to C: p=1) between the study groups. In particular, group B and group C showed worse outcomes and higher treatment failure rates than group A. Conclusion CSDH with homogeneous density on CT was characterized by signal intensity on DW-MRI. In CSDH patients, performing DW-MRI as well as CT helps to predict postoperative treatment failure or complications.

Increased Ratio of Superficial Temporal Artery Flow Rate After Superficial Temporal Artery-to-Middle Cerebral Artery Anastomosis: Can It Reflect the Extent of Collateral Flow?

OBJECTIVEnThere are several ways to identify donor artery patency and success of surgery after an anastomosis of the superficial temporal artery (STA) to the middle cerebral artery (MCA). The purpose of this study was to evaluate the ratio of bilateral STA mean flow rate (MFR) with the use of color Doppler ultrasonography (CDUS) after bypass surgery and to confirm the possibility of this value as a predictor of the extent of collateral flow.nnnMETHODSnEleven consecutive patients who had undergone STA-MCA anastomosis were included. In every case, bilateral STA MFR, mean velocity, and cross-sectional diameter were measured preoperatively and postoperatively at 1 week, 1 month, and 2 months via CDUS. We measured the bilateral STA MFR ratio changes to compensate for systemic hemodynamic variables.nnnRESULTSnOne month after surgery, 9 of the 11 patients who underwent STA-MCA anastomosis had good patency on DSA. In patients with good patency, there was a significant increase in the baseline STA MFR ratio compared with those at 1 week, 1 month, and 2 months postoperatively (2.88, 3.07, and 4.38, respectively, P < 0.05). The mean STA cross-sectional diameter ratio also was significantly increased postoperatively in the good patency group (1.35, 1.41, and 1.49, respectively, Pxa0= 0.044). In addition, the mean STA mean velocity ratio was increased postoperatively in the good patency group (1.48, 1.40, and 1.67, respectively, Pxa0= 0.042).nnnCONCLUSIONSnWe conclude that using CDUS to measure both STA MFR ratio is a potential method to predict the extent of collateral flow through an STA-MCA anastomosis.

Hidden Dense Middle Cerebral Artery Sign in a 4-Year-Old Boy With Traumatic Subarachnoid Hemorrhage

A 4-year-old boy was admitted with acute onset of hemiplegia of the right side that was secondary to a traffic accident. Initial computed tomography revealed a traumatic subarachnoid hemorrhage, and follow-up computed tomography showed a more localized hematoma of the left sylvian cistern. After a few days of conservative treatment, magnetic resonance imaging (MRI) revealed a cerebral infarction of the left lenticulostriate territory, even though magnetic resonance angiography showed preserved middle cerebral artery flow. Thus, we realized that the hematoma of the sylvian cistern was the so-called dense middle cerebral artery sign. This case of posttraumatic infarction suggested the importance of meticulous investigations and clinical correlations of imaging studies in pediatric patients with head injuries.

Reduction cranioplasty for macrocephaly with long-standing hydrocephalus and non-fused fontanelle in Chiari malformation type I

IntroductionBecause hydrocephalus is diagnosed and treated at an early stage in pediatric patients, pediatric neurosurgeons rarely encounter patients with hydrocephalic macrocephaly. There are even fewer cases of infants with long-standing hydrocephalus in whom macrocephaly progresses and is accompanied by skull defect due to malunion of suture lines despite long-term CSF diversion treatment.Case reportWe report the case of a male infant with Chiari malformation type I who presented with congenital hydrocephalus and occipital encephalocele that progressed to hydrocephalic macrocephaly with frontal skull defect, despite numerous cerebrospinal fluid diversion operations. The patient eventually recovered successfully after reduction cranioplasty.