DEVELOPMENT OF THE SPINE FOLLOWING PINEALECTOMY OR SENSORY MOTOR CORTICAL AREA DAMAGE IN GROWING RATS

Abstract

The aetiology of idiopathic scoliosis, despite of long-lasting efforts to disclose it, remains unknown.

The purpose of the study was to evaluate the spine development after pinealectomy or cortical sensory motor area damage in the growing rats.

Method: The authors operated 69 Wistar albino rats (aged three to four weeks) in antraperitoneal anaesthesia. In the first group (22 rats) pinealectomy – PIN was performed, in the second one (25) the sensory motor cortical area 2x1x1 mm bellow the coronal suture was removed – SMCA. The sham operation consisted of craniotomy – CRA (11 rats) and craniotomy with durotomy – CRDU (11 rats). All surgeries were performed from the left side. Radiography was made three months after surgery. Scoliosis, C2-T7 lordosis, T7-S1 kyphosis were measured. Results have been processed by software Statistica 7.1. StatSoft, Inc. (2005). We used ANOVA test for evaluation of potential difference between groups, in the case of approving the difference between groups, we tested difference between each two groups by two-sample t-test. Those tests were realised on 0,05 significant level.

Results: In the PIN group scoliosis 9–14 degrees (mean value 10,8) developed in five animals, in SMCA group scoliosis 10 – 24 degrees (mean value 15,9) was observed in eight animals.

These statistically significant differences were found: higher surgery weight in PIN, longer surgery time in PIN and SMCA, lower lordosis in PIN and higher in CRDU, differences of all groups in kyphosis and in an end weight.

Conclusion: Our results indicate the importance of cortical area damage, together with craniotomy and durotomy in the development of growing rat spine. We cannot exclude the influence of peri-operative bleeding, brain hypoxia or metabolic effect of anaesthetics.

These damages could cause a disorder of balance between smaller inhibitory and greater facilitating area of CNS, controlling the muscular tone and resulting in the development of lordosis and scoliosis due to muscle imbalance.