Development of the spine following pinealectomy or sensorimotor cortical area damage

The aim of this experimental study was to assess the spine development in growing rats following pinealectomy or partial sensorimotor cortical area damage. A total of 68 Wistar albino rats (Rattus norvegicus v. alba f. domestica) aged 3-4 weeks were divided into four groups. In group 1 (n = 22) pinealectomy was performed, in group 2 (n = 24) the sensorymotor cortical area 2 x 1 x 1 mm below the coronal suture was removed. Sham operation consisted of a craniotomy (n = 11) and a craniotomy with a durotomy (n = 11). All surgeries were performed from the left side. The rats were killed four months after surgery and radiography was then made. Scoliosis, C2-T7 lordosis and T7-S1 kyphosis were measured. The brains of rats after sensorimotor cortical area removal were isolated and investigated including histological examination (light microscope). Scoliosis of 9-14 degrees (mean value 10.8) was developed in five animals after pinealectomy; in rats after removal of the sensorimotor cortical area scoliosis of 10-24 degrees (mean value 15.9) was observed in eight animals. The scoliotic curves were non structural. Our results indicate the importance of cortical area damage, together with craniotomy and durotomy in the development of growing rat spine. These damages could cause a disorder of balance between smaller inhibitory and greater facilitating area of central nervous system, controlling the muscular tone and resulting in the development of increased lordosis and kyphosis and non structural scoliosis due to muscle imbalance. Thus the new hypothesis of scoliosis aetiology was introduced.