Examination of the effect of conservative treatment and surgical treatment on changes in sleep laboratory parameters in chiari type I malformation

Objective: Chiari Malformation Type 1 (CM I) is a common craniovertebral junction pathology in neurosurgery practice. Its relationship with sleep-disordered breathing has been shown in very few cases in the literature. For example, it has been shown that central sleep apnea, a sleep disorder, improves when the pathology is eliminated in CM I cases that underwent surgery. The aim of our study is to examine the possible changes in the neurophysiological mechanisms of sleep activity in CM I cases, and the changes that occur in the maintenance of sleep and therefore the health of the central nervous system with subsequent conservative or surgical treatment; to reveal electrophysiologically. Materials and Methods: At İnönü University Turgut Özal Medical Center Hospital, Brain and Nerve Surgery Clinic, between November 2014 and September 2022, 59 patients were diagnosed with Chiari type I malformation and followed up with conservative treatment and underwent suboccipital craniectomy - C1 laminectomy - duraplasty surgery. University Turgut Özal Medical Center Hospital Sleep Disorders Center Polysomnography laboratory parameters, file information and radiological imaging were examined retrospectively. While evaluating the findings obtained in the study, IBM SPSS Statistics 22 program was used for statistical analysis. Significance was evaluated at p<0.05 level. Findings: Our study included a total of 59 patients, 18 (30.5%) of whom were male and 41 (69.5%) of whom were female, aged between 17 and 64, out of 108 patients followed up with a diagnosis of CM I. As a result of surgery for CM I, it causes changes due to decompression, especially in the brainstem and pons. In our study, it was shown that total sleep time increased after surgery, consistent with studies in the literature. During sleep, NREM stage-1 consists of approximately 2-5%, NREM stage-2 45- 55%, and NREM stage-3 13-23%. In our study, a comparison could not be made because there was one patient in the surgical group whose herniation amount did not decrease. If the amount of herniation decreased in the non-surgical group, NREM stage-2 increased and the decrease in the amount of NREM stage-3 was found to be high. There is a statistically significant difference between the herniation groups in terms of the increase in the second sleep test compared to the N2 result in the first sleep test (p:0.038; p<0.05). As a result of the post hoc Dunn's test conducted to determine which groups the significance originates from; The increase in N2 level in the group whose herniation decreased was significantly higher than the group that remained the same (p:0.040; p<0.05). There is a statistically significant difference in the amount of change seen in the second sleep test compared to the N3 result in the first sleep test in the herniation groups (p:0.017; p<0.05). As a result of the post hoc Dunn's test conducted to determine which groups the significance originates from; The decrease in the N3 level of the group whose herniation decreased was found to be statistically significantly higher than the group that remained the same (p:0.013; p<0.05). In our study, in the surgically treated group with a BMI level below 30, the amount of increase seen in the second sleep test, according to the REM result in the first sleep test, is statistically significantly higher than in the group with a BMI level of 30 and above (p:0.014; p<0.05). It may be explained by the fact that BMI alone is a risk factor for sleeprelated breathing disorder. Results: We found the prevalence of sleep-related breathing disorders in 59 (54.62%) of 108 patients followed up with a diagnosis of CM I, which was higher than other studies in the literature. Sleep efficiency; It consists of the transition from wakefulness to sleep, the effort to maintain sleep, the continuity of sleep and sleep efficiency. In order for sleep to occur, there must be a transition period from sympathetic regulation to parasympathetic regulation. In our study, it was shown that total sleep time increased after surgery, consistent with studies in the literature. The main findings of our study showed that posterior fossa decompression caused significant improvement in many parameters of sleep-related breathing disorder. While there was a significant increase in total sleep time in patients who underwent decompression, it was determined that the effectiveness of the surgery showed a higher improvement compared to other studies in the literature, with an increase in the patients' REM time, a decrease in the central apnea index and the number of central apneas. In our study, in the polysomnography evaluations of sleep-related breathing disorder CM I patients who did not undergo surgery, it was observed that the central apnea index, central apnea duration and central apnea number of patients with a BMI below 30 were significantly lower than those of patients with a BMI of 30 and above. This can be explained by the fact that BMI alone is a risk factor for sleep-related breathing disorders. Considering the positive changes in sleep electrophysiology after surgery, electrophysiological signal recording during sleep (polysomnography) can be considered a criterion for the success of surgical treatment. In addition to our study, the number of patients can be increased and the follow-up period can be extended. Key Words: REM, Type 1 Chiari Malformation, Sleep Electrophysiology