Polysomnographic evaluation of sleep in Chiari Type 1 malformation before surgical decision and after surgery

Objectives / Instruction : Chiari malformation is known to be associated with sleep apnea but others sleep disorders could be identified. We report here our experience of nocturnal polysomnographic performed before surgical decision and after surgery of Chiari type 1 malformation
Methods : Retrospective analysis. Since 2010, we explored patients with Chiari malformation during the pre-operative assessment, and when possible or indicated after surgery. Nocturnal video-polysomnographic were performed in the sleep laboratory. Furthermore, at each evaluation, patient completed Epworth Sleepiness Scale (ESS), Pichot ADA asthenia scale, Pichot Q2DA depression scale and Modified Essay Questions (MEQ).
Results : Seventeen patients were recorded before surgical assessment and 6 after surgery. Mean age was 43 ± 13 years old. All patients have sleep fragmentation by arousals, due to Periodic Limb Movements (PLM) for 11 patients, and significative sleep apneas (mean 18/h) for 6 patients. Mean total sleep time (TST) was 405± 19 mn, under normal data from our sleep lab (mean = 415± 2 mn). REM sleep represented only 13% of the TST.
After surgery, we observed an increase of mean TST to 432± 25 mn (vs 385± 44 mn before) and of the REM sleep (17% of the TST vs 13% ) for the 6 reevaluated patients. Sleep apnea index decreased from 18 /h to 13/h and PLM appeared to be less frequent.-Considering self-evaluation, only ESS has significative abnormal results with a mean score at 11± 3 before surgery. For the 6 patients, all scores decreased after surgery : from 12 ± 2 to 6 ± 3 for ESS, 16 ± 5 to 7 ± 2 for ADA, 8 ± 3 to 3 ± 2 for Q2DA and 4 ± 2 to 1 ± 1 for MEQ.
Conclusions : Our retrospective data showed a higher association with PLM than to apneas in Chiari malformation. Furthermore, sleep architecture parameters were altered. So polygraphy was insufficient to explore sleep and a polysomnographic study has to be preferred.
Use of Epworth Sleepiness Scale questionnaire as a screening tool appeared to be useful for sleepiness evaluation before surgery.