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Ventral brain stem compression in pediatric and young adult patients with Chiari I malformations.
Neurosurgery. 1999 Mar; 44(3):520-7; discussion 527-8.N

Abstract

OBJECTIVE

The purposes of this study were as follows: 1) to determine the incidence and degree of ventral brain stem compression (VBSC) in pediatric and young adult patients with Chiari I malformations, and 2) to correlate VBSC with other imaging and clinical factors to help determine what amount of VBSC is successfully treated with a posterior decompressive procedure alone.

METHODS

The magnetic resonance images and clinical histories of 40 pediatric and young adult patients with Chiari I malformations were analyzed for subjective grade of VBSC, distance of tonsillar descent, odontoid's relation to Chamberlain's and Wackenheim's line, clival length, foramen magnum diameter, syringomyelia, scoliosis, hydrocephalus, presenting clinical status, treatment, and outcome. To objectively measure the amount of ventral cervicomedullary encroachment by the odontoid and its investing tissues into the rostral spinal canal, a line (B-C2) was drawn between the basion and posteroinferior aspect of the C2 body on a sagittal magnetic resonance image. A line perpendicular to this line, pB-C2, was drawn through the odontoid tip to the ventral dura, and a distance (representing the amount of ventral canal encroachment) was measured.

RESULTS

Flattening and distortion of the ventral brain stem were present in 48 and 28% of the patients, respectively. Only two patients had basilar invagination by traditional definitions. pB-C2 measurements correlated with the subjective grade of VBSC (P < 0.05), age, and distance of tonsillar descent (P < 0.05). Eye motion abnormalities and upper cervical osseous anomalies were associated with higher pB-C2 measurements. All patients with a pB-C2 measurement of less than 9 mm were treated successfully with posterior fossa decompression alone despite any subjective VBSC. Some patients with pB-C2 measurements greater than 9 mm had either preoperative neurological deficits or neurological worsening after posterior fossa decompression referable to VBSC.

CONCLUSION

Patients with a pB-C2 measurement of less than 9 mm do not require treatment directed at VBSC. In select patients with pB-C2 measurements of 9 mm or greater, reduction of VBSC may be prudent before posterior fossa decompression.

Authors+Show Affiliations

Department of Surgery, University of Alabama at Birmingham, Children's Hospital of Alabama, 35233, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

10069589

Citation

Grabb, P A., et al. "Ventral Brain Stem Compression in Pediatric and Young Adult Patients With Chiari I Malformations." Neurosurgery, vol. 44, no. 3, 1999, pp. 520-7; discussion 527-8.
Grabb PA, Mapstone TB, Oakes WJ. Ventral brain stem compression in pediatric and young adult patients with Chiari I malformations. Neurosurgery. 1999;44(3):520-7; discussion 527-8.
Grabb, P. A., Mapstone, T. B., & Oakes, W. J. (1999). Ventral brain stem compression in pediatric and young adult patients with Chiari I malformations. Neurosurgery, 44(3), 520-7; discussion 527-8.
Grabb PA, Mapstone TB, Oakes WJ. Ventral Brain Stem Compression in Pediatric and Young Adult Patients With Chiari I Malformations. Neurosurgery. 1999;44(3):520-7; discussion 527-8. PubMed PMID: 10069589.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ventral brain stem compression in pediatric and young adult patients with Chiari I malformations. AU - Grabb,P A, AU - Mapstone,T B, AU - Oakes,W J, PY - 1999/3/9/pubmed PY - 1999/3/9/medline PY - 1999/3/9/entrez SP - 520-7; discussion 527-8 JF - Neurosurgery JO - Neurosurgery VL - 44 IS - 3 N2 - OBJECTIVE: The purposes of this study were as follows: 1) to determine the incidence and degree of ventral brain stem compression (VBSC) in pediatric and young adult patients with Chiari I malformations, and 2) to correlate VBSC with other imaging and clinical factors to help determine what amount of VBSC is successfully treated with a posterior decompressive procedure alone. METHODS: The magnetic resonance images and clinical histories of 40 pediatric and young adult patients with Chiari I malformations were analyzed for subjective grade of VBSC, distance of tonsillar descent, odontoid's relation to Chamberlain's and Wackenheim's line, clival length, foramen magnum diameter, syringomyelia, scoliosis, hydrocephalus, presenting clinical status, treatment, and outcome. To objectively measure the amount of ventral cervicomedullary encroachment by the odontoid and its investing tissues into the rostral spinal canal, a line (B-C2) was drawn between the basion and posteroinferior aspect of the C2 body on a sagittal magnetic resonance image. A line perpendicular to this line, pB-C2, was drawn through the odontoid tip to the ventral dura, and a distance (representing the amount of ventral canal encroachment) was measured. RESULTS: Flattening and distortion of the ventral brain stem were present in 48 and 28% of the patients, respectively. Only two patients had basilar invagination by traditional definitions. pB-C2 measurements correlated with the subjective grade of VBSC (P < 0.05), age, and distance of tonsillar descent (P < 0.05). Eye motion abnormalities and upper cervical osseous anomalies were associated with higher pB-C2 measurements. All patients with a pB-C2 measurement of less than 9 mm were treated successfully with posterior fossa decompression alone despite any subjective VBSC. Some patients with pB-C2 measurements greater than 9 mm had either preoperative neurological deficits or neurological worsening after posterior fossa decompression referable to VBSC. CONCLUSION: Patients with a pB-C2 measurement of less than 9 mm do not require treatment directed at VBSC. In select patients with pB-C2 measurements of 9 mm or greater, reduction of VBSC may be prudent before posterior fossa decompression. SN - 0148-396X UR - https://www.unboundmedicine.com/medline/citation/10069589/Ventral_brain_stem_compression_in_pediatric_and_young_adult_patients_with_Chiari_I_malformations_ L2 - https://academic.oup.com/neurosurgery/article-lookup/doi/10.1097/00006123-199903000-00050 DB - PRIME DP - Unbound Medicine ER -