Physiological rapid growth of spinal lipoma in the early postnatal period.

OBJECTIVE: Spinal lipomas are congenital malformations. They do not express tumorous growth but are found to increase in volume like other normal subcutaneous fat tissue during the early postnatal period. To understand the natural course of volume changes in spinal lipomas, the authors measured the changes in size of spinal lipomas together with the normal subcutaneous fat in relation to BMI. METHODS: A total of 27 patients with conus spinal lipoma excluding lipomyelomeningocele who underwent MRI twice before surgery (on initial diagnosis and immediately preoperatively) were included. Patients' ages at the time of the first MRI ranged from 0 to 32 months (mean 2.9 months, median 1 month). Candidates were categorized by age into three groups: < 1 month, 1-2 months, and ≥ 3 months. The growth rate of the spinal lipomas (in three directions), change in thickness of the normal subcutaneous fat, growth rate of the normal spinal canal (dorsoventral direction), and change in BMI were retrospectively analyzed between the three groups. RESULTS: The mean interval between MRI studies was 83.1 days. During this time, the mean lipoma growth rates were 199%, 149%, and 133% in the dorsoventral, lateral, and craniocaudal directions, respectively (with 100% representing the first measurement). The mean change in the thickness of the normal subcutaneous fat was 183%. The mean growth of the normal spinal canal was 111%. The mean increase in BMI was 124%. These rates were all significantly higher in the younger groups. There was no significant difference in the growth rates between the lipoma and the subcutaneous fat in every age group. In contrast, the growth rate of the lipoma significantly exceeded that of the spinal canal in patients younger than 3 months. The subarachnoid space around the lipoma became obstructed in 35.3%, and spinal cord distortion occurred in 48.1% of the patients younger than 3 months. CONCLUSIONS: Spinal lipomas rapidly increase in volume before the age of 3 months and especially in infants younger than 1 month. Their features closely correlate with the physiological growth of the normal subcutaneous fat and the increase in BMI. The rapid growth of lipomas suggests the importance of close observation in this period, keeping in mind the typical anatomical changes of lipomas and their surrounding structures.

Physiological defects of lumbosacral vertebral arches on computed tomography images in children.

OBJECTIVE: Physiological midline defects of the lumbosacral vertebral arches on radiographs must be distinguished from pathological spina bifida. To date, however, this has not been examined, except for some reports based on plain radiography. The aim of this study is to accurately define the rate and distribution of physiological defects by computed tomography (CT) imaging. METHODS: A total of 115 patients aged 0 months to 16 years (median age, 4 years) who underwent CT scans for abdominopelvic disorder not involving the lumbosacral spine were retrospectively analyzed. The lumbosacral spines were collaterally identified on these images. RESULTS: In the lumbosacral spine excluding the sacral hiatus, the rate of physiological defects was 66.1% (95% confidence interval [CI]: 56.7-74.7%), and the mean number of defective vertebral arches was 1.6 per patient (95% CI: 1.3-1.9). The rate and mean number of defects were significantly higher in the group of patients less than 6 years old (84.3%, 2.2/patient) than that of patients 6 years old or older (37.8%, 0.5/patient) (p < 0.001 and p < 0.001, respectively). The defect rates by spinal level were S3 (57.4%), S1 (47.8%), S2 (34.8%), L5 (13.0%), L4 (2.6%), and L3 (0.9%) in descending order. CONCLUSIONS: Physiological defects were found more commonly at an earlier age and predominantly existed adjacent to the sacral hiatus (S3) and around S1. Understanding the detection rate and distribution features of defects more precisely on CT images will contribute clinically supportive information to distinguish between physiological defects and pathological spina bifida.

Optimization of a therapeutic protocol for intravenous injection of human mesenchymal stem cells after cerebral ischemia in adult rats.

The systemic injection of human mesenchymal stem cells (hMSCs) prepared from adult bone marrow has therapeutic benefits after cerebral artery occlusion in rats, and may have multiple therapeutic effects at various sites and times within the lesion as the cells respond to a particular pathological microenvironment. However, the comparative therapeutic benefits of multiple injections of hMSCs at different time points after cerebral artery occlusion in rats remain unclear. In this study, we induced middle cerebral artery occlusion (MCAO) in rats using intra-luminal vascular occlusion, and infused hMSCs intravenously at a single 6 h time point (low and high cell doses) and various multiple time points after MCAO. From MRI analyses lesion volume was reduced in all hMSC cell injection groups as compared to serum alone injections. However, the greatest therapeutic benefit was achieved following a single high cell dose injection at 6 h post-MCAO, rather than multiple lower cell infusions over multiple time points. Three-dimensional analysis of capillary vessels in the lesion indicated that the capillary volume was equally increased in all of the cell-injected groups. Thus, differences in functional outcome in the hMSC transplantation subgroups are not likely the result of differences in angiogenesis, but rather from differences in neuroprotective effects.