gms | German Medical Science

Objective: The pineal gland as a melatonin-producing organ is suggested to be involved in the regulation of sleep and circadian rhythm. However, according to published data only 25–54% of patients after pinealectomy suffer from sleep disturbances (Macchi, 2004). Moreover, previous studies have not controlled for confounding factors such as chronotype, preexisting sleep disturbances, insomnia related to comorbid depression or preexisting changes in salivary melatonin concentration that might have been caused by tumour growth.

Method: 8 consecutive patients with pineocytoma WHO°I that were considered for pinealectomy were prospectively assigned to the study. Before and 3 months after pinealectomy we performed a clinical interview by a sleep expert, two consecutive nights of polysomnography as well as 2 weeks of actimetry and sleep log. Moreover, subjects completed the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the Beck Depression Inventory and the Morningness Eveningness Questionnaire (D-MEQ). At the evenings before polysomnography we assessed salivary dim-light melatonin onset (>3 pg/ml) within a time frame that was approximated by the individual D-MEQ score.

Results: In all subjects assessed to date preoperative salivary dim-light melatonin onset was within the expected physiological range but postoperative salivary melatonin was below detection levels. However, sleep patterns did not appear to be changed in relation to pinealectomy.

Conclusions: Although pinealectomy causes a lack of detectable salivary melatonin this is not related to changes in sleep patterns three months post surgery. Melatonin secretion in other organs that is undetectable in salivary samples might compensate for the lack of pineal melatonin secretion or the exclusive removal of circadian pineal melatonin release does not destroy the complex regulation of sleep within the relatively short time of three months post pinealectomy.