gms | German Medical Science

Objective: Today, radical resection of midline malignant tumors of the posterior fossa in childhood followed by adjuvant therapies like chemotherapy or radiation often leads to long-term survival and even healing of such patients. Therefore, the quality of life of these patients becomes particular important. Postoperative neurological deficits, such as cerebellar mutism and ataxia, may be attributed to splitting of the cerebellar vermis, which is often used as a surgical approach to remove these tumors. Here, we tested the effect of vermian splitting on motor and social behaviour in juvenile rats.

Methods: In male Sprague Dawley rats, age of 23 days, the cerebellar vermis was split under anaesthesia after medial suboccipital craniotomy with opening of the foramen magnum (lesioned group, n=16). In sham-lesioned rats, only the dura was opened with release of cerebrospinal fluid (n=16). Naïve rats served as controls (n=14). All groups were tested on day 0 (before surgery), and on days 1, 2, 3, 4 and 7 after surgery for locomotor activity (distance in the open field), motor coordination (rotarod test), social behaviour (play fighting with a social partner), and communication (ultrasound vocalization [USV] during social interaction). Finally, splitting of the vermis was histologically verified.

Results: Locomotor activity was reduced one day after operation in both lesioned and sham-lesioned rats (p < 0.05). Only in lesioned rats rotarod testing revealed reduced motor coordination (days 1 and 2), as well as a decrease of social play fighting (days 1 and 2) and USV (day 1).

Conclusions: While the decrease in locomotor activity seems to be surgery related, deterioration of the motor coordination and deficient social behavior seem to be related to vermian splitting. These results indicate that in analog to the human context vermian splitting can reduce communicative drive in the early postsurgical phase.