We investigated, with magnetic resonance imaging, the distance of the dura mater to the spinal cord in patients without spinal or medullar disease at the 2nd, 5th, and 10th thoracic segments.
Fifty patients in the supine position underwent magnetic resonance imaging. Medial sagittal slices of the 2nd, 5th, and 10th thoracic segments were measured for the relative distances using the 1.5-T superconducting system (Gyroscan Intera, Philips Medical Systems, Best, the Netherlands). In 10 patients, the angles relative to the tangent at the insertion point on the skin were measured.
The posterior dural-spinal cord distance is significantly greater at the midthoracic region (5th thoracic = 5.8 ± 0.8 mm) than at the upper (2nd thoracic = 3.9 ± 0.8 mm) and lower thoracic levels (10th thoracic = 4.1 ± 1.0 mm) (P < 0.015). There were no differences between interspaces T2 and T10. There was no correlation between age and the measured distance between the dura mater and the spinal cord. The entry angle of the needle at T2 was 9.0° ± 2.5°; at T5, 45.0° ± 7.4°; and at T10, 9.5° ± 4.2°.
This study demonstrated that there is greater depth of the posterior subarachnoid space at the T2, T5, and T10 levels. The greater distance was found at T5.
Published ahead of print March 19, 2010 Supplemental Digital Content is available in the text.
From the *Hospital de Base-FAMERP, São José do Rio Preto, Sao Paulo; †Botucatu Medical School, University of São Paulo State, UNESP, Botucatu; ‡School of Medicine-FAMERP, and §Department of Radiology and Imaging and ¶Department of Biostatistics, Hospital de Base—FAMERP, São Josédo Rio Preto, Sao Paulo, Brazil.
Address correspondence and reprint requests to Dr. Luiz Eduardo Imbelloni, Av. Epitácio Pessoa, 2356/203, 22411-072 Rio de Janeiro, Brasil. Address e-mail to firstname.lastname@example.org.
Accepted January 11, 2010
Published ahead of print March 19, 2010