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Complete Gas Myelography via Lumbar Injection under Pressure

1967; Radiological Society of North America; Volume: 88; Issue: 5 Linguagem: Inglês

10.1148/88.5.917

1527-1315

Luis G. Feria, C. Rådberg,

Infectious Diseases and Tuberculosis

Usually, myelography with complete gas-filling of the spinal subarachnoid space is performed via suboccipital puncture, with the technic recommended by Lindgren (8, 9). Odén (13), among others, has shown that gas myelography under these conditions is at least as accurate as myelography with iodized oils for the diagnosis of space-occupying lesions. Important features of the method are: (a) the contrast material, gas, is completely absorbed without residual adhesions and granulomas; (b) fluoroscopy is unnecessary; and (c) errors due to incomplete contrast-filling are avoided (10). Gas myelography by the Lindgren cisternal technic has gained only limited use, however, in spite of its good results and the innocuousness of gas as the contrast material. One reason for this may be reluctance to perform suboccipital puncture because of the associated risks. Further, suboccipital puncture is sometimes contraindicated or impossible because of skeletal anomalies or intraspinal lesions at the level of the foramen magnum. Lindgren recommended lumbar injection of gas if only the lumbar and lower thoracic regions were to be investigated and advocated injection up to a pressure of 500–600 mm H20 to achieve distention of the subarachnoid space (9). Lumbar injection of gas has also been used, however, to investigate the cervical region (1, 4, 14, 19). All the methods described have deficiencies, the most common of which is incomplete gas filling. It is known that the resorption of spinal fluid is augmented when the intrathecal pressure is increased (3, 11, 15). We have employed this increased resorption to achieve complete gas-filling up to the foramen magnum via lumbar injection in high pelvic position. No previous lumbar method seems to have regularly permitted this. Technic The spinal fluid is removed in two stages, first by tapping and later by increasing the pressure. Tapping Period: After lumbar puncture a jugular compression test is performed. If this is negative, as much spinal fluid as possible is tapped with the patient in either the sitting or the lateral decubitus position and with the head elevated 10–15°. Within ten to fifteen minutes, 50–80 ml are usually obtained. The fluid drips faster when the patient is in the sitting position, but he has more discomfort from headache and fall in blood pressure, and therefore we prefer the lateral decubitus position. When the drip from the needle begins to slow, the stopcock is closed and the patient is placed in the lateral decubitus position with the head lowered 15–20°. The needle is fitted with a two-way stopcock, permitting simultaneous registration of the pressure and the gas injection. The injection is made with a speed of about 5 ml per minute and continued until a pressure of about 550 mm H20 is reached. At this stage the gas-filling usually approaches the middle or upper thoracic region.