The effects of posterior fossa decompressive surgery in adult patients with Chiari malformation and sleep apnea

Clinical article

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One of the feared consequences of craniovertebral junction diseases is apnea. Although several cases of patients with central apnea have been described, obstructive sleep apnea has been identified as the most frequent manifestation of sleep respiratory disorder. Neuronal involvement may be responsible for both central and obstructive apneas. The objective of this work was to study the effect of posterior fossa decompressive surgery on respiratory parameters during sleep in patients with craniovertebral junction malformations and breathing-related sleep disorders.


In this study, prospectively enrolled consecutive symptomatic adult patients were monitored with full-night polysomnography before and after surgical decompression of the cranial posterior fossa.


Of the 25 patients who were evaluated, 68% received a diagnosis of sleep apnea. After surgery, the mean number of respiratory events decreased from 180.70 to 69.29 (p = 0.005); the mean number of obstructive events decreased from 107.37 to 60.58 (p = 0.01); and the mean number of central events decreased from 38.45 to 8.05 (p = 0.01). The mean preoperative apnea/hypopnea index decreased from 26.68 to 12.98 (p = 0.06), and the mean central apnea index decreased from 13.81 to 1.68 (p = 0.01).


Decompressive surgery in patients with craniovertebral junction malformations resulted in decreased respiratory events during sleep, lowered sleep fragmentation, and enhanced the sleep apnea index in a significant number of patients. The effect was more pronounced in patients with central apnea.

Abbreviations used in this paper: AHI = apnea/hypopnea index; BI = basilar invagination; BMI = body mass index; CAI = central apnea index; CM = Chiari malformation; CVJM = craniovertebral junction malformation; EEG = electroencephalogram; EMG = electromyogram; EOG = electrooculogram.

Article Information

Address correspondence to: Ricardo Vieira Botelho, M.D., Ph.D., Department of Neurosurgery, Hospital do Servidor Publico de Estado, Haberbeck Brandão 68-92, Indianópolis-São Paulo, Brazil 04026040. email:

Please include this information when citing this paper: published online August 7, 2009; DOI: 10.3171/2009.7.JNS09174.

© AANS, except where prohibited by US copyright law.



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    Intraoperative photograph showing extraarachnoidal decompression according to the modified Sahuquillo technique but without anchoring the dura mater.

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    Preoperative (left) and postoperative (right) MR images demonstrating the reappearance of the cisterna magna, narrowing of syringomyelia cavity, and the presence of CSF in the craniocervical junction.

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    Preoperative (A, C, E, and G) and postoperative (B, D, F, and H) pairs of MR images obtained in 4 patients. In these cases, the new cisterna magna formation and narrowing of the syringomyelia cavity may be seen. The patients whose MR images are displayed in the upper left (A and B) and lower left (E and F) pairs of panels were treated with cranial traction and craniocervical fixation to reduce the BI.

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    Boxplot graphs showing preoperative (Pre) and postoperative (Post) findings in patients with CMs. Left: Sleep respiratory events. CE = central events; OE = obstructive events; RE = respiratory events. Right: The AHI and CAI scores. The p values represent the Wilcoxon estimated Type I error. Numbers on the y axis represent the number of events (left) and the index score (right).

  • View in gallery

    Diagnostic MR imaging studies of the patients with central apnea.


  • 1

    Alvarez DRequena IArias MValdés LPereiro IDe la Torre R: Acute respiratory failure as the first sign of Arnold–Chiari malformation associated with syringomyelia. Eur Respir J 8:6616631995

  • 2

    Anonymous: EEG arousals: scoring rules and examples: a preliminary report from the Sleep Disorders Atlas Task Force of the American Sleep Disorders Association. Sleep 15:1731841992

  • 3

    Bindal AKDunsker SBTew JM Jr: Chiari I malformation: classification and management. Neurosurgery 37:106910741995

  • 4

    Bokinsky GEHudson LDWeil JV: Impaired peripheral chemosensitivity and acute respiratory failure in Arnold–Chiari malformation and syringomyelia. N Engl J Med 288:9479481973

  • 5

    Botelho RVBittencourt LRRotta JMNery LETufik S: Apnéia do sono central em paciente com malformaçäo de Chiari tipo I e siringomielia: tratamento com cirurgia descompressiva. Relato de caso. J Bras Neurocir 9:1111141998

  • 6

    Botelho RVBittencourt LRRotta JMTufik S: Adult Chiari malformation and sleep apnoea. Neurosurg Rev 28:1691762005

  • 7

    Botelho RVBittencourt LRRotta JMTufik S: Prospective controlled study of sleep respiratory events in patients with craniovertebral junction malformation. J Neurosurg 99:100410092003

  • 8

    Dauvilliers YStal VAbril BCoubes PBobin STouchon J: Chiari malformation and sleep related breathing disorders. J Neurol Neurosurg Psychiatry 78:134413482007

  • 9

    Di XLuciano MGBenzel EC: Acute respiratory arrest following partial suboccipital cranioplasty for cerebellar ptosis from Chiari malformation decompression. Report of 2 cases. Neurosurg Focus 25:6E122008

  • 10

    Doherty MJSpence DPYoung CCalverley PM: Obstructive sleep apnoea with Arnold–Chiari malformation. Thorax 50:6906911995

  • 11

    Ely EWMcCall WVHaponik EF: Multifactorial obstructive sleep apnea in a patient with Chiari malformation. J Neurol Sci 126:2322361994

  • 12

    Flemons WWTsai W: Quality of life consequences of sleepdisordered breathing. J Allergy Clin Immunol 99:S750S7561997

  • 13

    Gagnadoux FMeslier NSvab IMenei PRacineux JL: Sleepdisordered breathing in patients with Chiari malformation: improvement after surgery. Neurology 66:1361382006

  • 14

    Johns MW: A new method for measuring daytime sleepiness: the Epworth Sleepiness Scale. Sleep 14:5405451991

  • 15

    Marin-Padilla MMarin-Padilla TM: Morphogenesis of experimentally induced Arnold-Chiari malformation. J Neurol Sci 50:29551981

  • 16

    Melendres MCLutz JMRubin EDMarcus CL: Daytime sleepiness and hyperactivity in children with suspected sleepdisordered breathing. Pediatrics 114:7687752004

  • 17

    Miralbés Terraza SGarcía Oguiza ALópez Pisón JSáenz Moreno IJiménez Escobar VPena Segura JL: [Central sleep apnea syndrome as the first sign of type I Chiari malformation.]. An Pediatr (Barc) 68:2772812008. (Span)

  • 18

    Nishikawa MSakamoto HHakuba ANakanishi NInoue Y: Pathogenesis of Chiari malformation: a morphometric study of the posterior cranial fossa. J Neurosurg 86:40471997

  • 19

    Omer Sal-Kawi MZBohlega SBouchama AMclean D: Respiratory arrest: a complication of Arnold–Chiari malformation in adults. Eur Neurol 36:36381996

  • 20

    Rabec CLaurent GBaudouin NMerati MMassin FFoucher P: Central sleep apnoea in Arnold–Chiari malformation: evidence of pathophysiological heterogeneity. Eur Respir J 12:148214851998

  • 21

    Rechtschaffen AKales A: A Manual of Standardized Terminology and Scoring System for Sleep Stages of Human Subjects Bethesda, MDNational Institute of Neurological Diseases and Blindness1968

  • 22

    Sahuquillo JRubio EPoca MARovira ARodriguez-Baeza ACervera C: Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex—preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration. Neurosurgery 35:8748841994

  • 23

    Stephany JDGaravaglia JCPearl GS: Sudden death in a 27-year-old man with Chiari I malformation. Am J Forensic Med Pathol 29:2492502008

  • 24

    Tsara VSerasli EKimiskidis VPapagianopoulos SKatsaridis VFylaktakis M: Acute respiratory failure and sleep-disordered breathing in Arnold–Chiari malformation. Clin Neurol Neurosurg 107:5215242005

  • 25

    Wiegand LZwillich CW: Obstructive sleep apnea. Dis Mon 40:1972521994

  • 26

    Yglesias ANarbona JVanaclocha VArtieda J: Chiari type I malformation, glossopharyngeal neuralgia and central sleep apnoea in a child. Dev Med Child Neurol 38:112611301996

  • 27

    Young TPalta MDempsey JSkatrud JWeber SBadr S: The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med 328:123012351993

  • 28

    Zolty PSanders MHPollack IF: Chiari malformation and sleep-disordered breathing: a review of diagnostic and management issues. Sleep 23:6376432000

  • 29

    Zonato AIMartinho FLBittencourt RAde Oliveira Camponês Brasil OGregório LCTufik S: Head and neck physical examination: comparison between nonapneic and obstructive sleep apnea patients. Laryngoscope 115:103010342005




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