The posterior atlanto-occipital membrane (PAO) contributes little to craniocervical stability and is generally underappreciated and incised with most suboccipital craniectomies. We report a case of a child who underwent posterior fossa decompression for Chiari I malformation with syringomyelia whose symptoms had not resolved months after surgery. A secondary exploratory operation revealed a healed constricting PAO which had been incised linearly at the initial operation. This patient’s symptoms improved soon after the second surgery. We propose that attention be given to this membrane, and if it is incised with underlying dura mater as in a standard posterior fossa decompression, it should be removed or cauterized separately and laterally to inhibit its reformation.

Keywords:
Posterior atlanto-occipital membrane, Tonsillar ectopia, Dural band, Hindbrain herniation, Chiari I malformation
1.
Yundt KD, Park TS, Tantuwaya VS, Kaufman BA: Posterior fossa decompression without duraplasty in infants and young children for treatment of Chiari malformation and achondroplasia. Pediatr Neurosurg 1996;25:221–226.
2.
Oakes WJ, Tubbs RS: Chiari malformations; in Winn HR (ed): Youman’s Neurological Surgery: A Comprehensive Reference Guide to the Diagnosis and Management of Neurosurgical Problems, ed 5. Philadelphia, Saunders, in press.
3.
Isu T, Sasaki H, Takamura H, Kobayashi N: Foramen magnum decompression with removal of the outer layer of the dura as treatment for syringomyelia occurring with Chiari I malformation. Neurosurgery 1993;33:845–850.
4.
VanGilder JC, Menezes AH, Dolan KD: The Craniovertebral Junction and Its Abnormalities. Mount Kisco, Futura, 1987, p 14.
5.
Testut L, Jacob O: Traité d’Anatomie Topographique avec Applications Médico-Chirurgicales. Paris, Octave, 1909, pp 575–577.
6.
Yong-Hing K, Reilly J, Kirkaldy-Willis WH: The ligamentum flavum. Spine 1976;1:226–234.
7.
Bogduk N: Anatomy of the spine; in White AH (ed): Spine Care. St. Louis, Mosby, 1995, vol 2, p 821.
8.
Ghanayem AJ, Zdeblick TA, Dvořák J: Functional anatomy of joints, ligaments, and discs; in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, Lippincott-Raven, 1998, p 46.
9.
Harris MB, Duval MJ, Davis JA Jr, Bernini PM: Anatomical and roentgenographic features of atlantooccipital instability. J Spinal Disord 1993;6:5–10.
10.
Sun PP, Poffenbarger GJ, Durham S, Zimmerman RA: Spectrum of occipitoatlantoaxial injury in young children. J Neurosurg 2000;93(1 suppl):28–39.
11.
Du Chesne A, Fechner G, Brinkmann B: The distinction between lacerations and cuts in ligaments and tendons. Int J Legal Med 1996;109:1–4.
12.
Tubbs RS, Wellons JC, Blount JP, Oakes WJ: Utilization of the posterior atlanto-occipital membrane for duraplasty. J Neurosurg, in press.
13.
Shimizu T, Waga S, Kojima T, Niwa S: Decompression of the vertebral artery for bow-hunter’s stroke. Case report. J Neurosurg 1988;69:127–131.
14.
Sakai K, Tsutsui T: Bow hunter’s stroke associated with atlantooccipital assimilation – case report. Neurol Med Chir (Tokyo) 1999;39:696–700.
15.
Piersol GA: Human Anatomy: Including Structure and Development and Practical Considerations. Philadelphia, Lippincott, 1907, p 137.
© 2003 S. Karger AG, Basel
2003
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