Somatotrophic reorganization in the brain after extremity replantation, revascularization and amputations: investigated by SPECT analysis.

BACKGROUND: We wanted to investigate the somatotropic reorganization occurring in the motor and somatosensory cortex by using 99mTc-HMPAO SPECT analyses, after the extremity revascularization, replantation or amputation. METHODS: Twelve patients (11 men, 1 female; mean age 38.9+/-14.7 years) and controls (5 men, mean age 32.2+/-7.9 years) were enrolled in this study. After reconstruction, lower, middle and upper orbitomeatal slices with precentral and postcentral slices were obtained. All images were visually and semi-quantitatively evaluated. Mann-Whitney U-test was used for statistical analysis. RESULTS: In the revascularization and replantation patients, postcentral and precentral hypoperfusions were seen at dominant hemisphere. In the amputated patients, postcentral (in 3 of 4 cases) and precentral hypoperfusions were seen at non-dominant hemisphere and postcentral hypoperfusion (in 1 of 4 cases) was seen at dominant hemisphere. In our patients, most significant difference in regional cerebral blood flow was found in posterior parietal cortex (somatic associated area). CONCLUSION: Changes that take place in precentral and postcentral cortical areas subsequent to the extremity replantation-revascularization of the organ is a good indicator of somatotrophic reorganization.

Magnetic resonance spectroscopy study of proton metabolite level changes in sensorimotor cortex after upper limb replantation-revascularization.

We aimed to investigate the changes in proton metabolite levels at the motor and somatosensory cortex by magnetic resonance spectroscopy (MRS) after upper extremity replantation or revascularization. Nine patients who referred to our clinic suffering from major total (two) and subtotal (seven) amputation of the upper extremity were enrolled in this study. Mean time value between the injury and operation was 5.1 h. Mean follow-up period or mean time between the injury and MRS analysis was 26.2 months (ranging from 7 to 41 months). Voxels (TR: 2000; TE: 136 ms) were placed onto locations in the bilateral precentral and postcentral cortex area of the cerebral hemispheres that represent the upper extremity. Contralateral sides of the brain hemisphere that represent the injured extremity were accounted as control groups. Metabolite ratios [NAA (N-acetyl aspartate)/Cr (creatine) and Cho (choline)/Cr] of the motor and somatosensory cortex were calculated. The NAA/Cr and Cho/Cr metabolite ratios between the two groups were found to be insignificant, and these results may indicate that there is no remarkable somatosensorial cortex disruption or demyelination in these patients. Fifty-six percent of patients were found as functional according to Chen's scale.

Induced angiogenesis with intramedullary direct current: experimental research.

The purpose of this study was to evaluate angiogenesis after the use of intramedullary direct electrical current in rabbit tibia. Thirty-two New Zealand rabbits were divided into four groups: group 1, false electrode group; group 2, hole group; group 3, control group; and group 4, intramedullary electrical stimulation group. One-half of the rabbits in each group were evaluated angiographically, pathologically, and scintigraphically on day 7, and the rest were evaluated on day 21. Results proved that electrical stimulation was not capable of the induction of angiogenesis in the subjects killed on day 7 and day 21. Furthermore, we found some fibrotic changes secondary to electrical stimulation on day 7 (P = 0.04) and day 21 (P = 0.01). However, an increase in new capillary vessels occurred in the false electrode group (P = 0.02). We found no useful effect of electrical stimulation in our study, a finding that is possibly due to our use of a method previously undocumented in the literature. We believe that this study can be the new baseline for further studies into the stimulation or inhibition of angiogenesis using intramedullary wire with or without electrical stimulation.