The role of water-soluble contrast myelography implications for the Caribbean - abstract

ABSTRACT

Since 1985, water-soluble contrast medium has been used for myelography in Trinidad; it has distinct advantages over the traditional oily medium. It is rapidly excreted in the urine so that it does not need removal. A smaller (20-22 gauge) spinal needle is used; less trauma causes less CSF leakage and hence less post-spinal headache. The needle is removed after contrast injection, allowing easier patient manipulation. The low viscosity contrast also gives a better view of the thecal sac, spinal cord and nerve roots; further, it can traverse a lesion enabling both cephalad and caudal margin delineation. Fluoroscopy is not absolutely necessary as the 5-30 degree head up postero-anterior and obliques show a lumber lesion. Further, it can be used as an outpatient procedure and allows for enhanced CT scanning. There were 57 cases in the 3 years from 1985 to 1987 (7, 15, 35) 30 at San Fernando, 12 at Port-of-Spain and 15 in private clinics. The 36 males and 21 females were aged 23 to 62 years; 54 had low-back syndrome, 2 suspected thoracic and the other suspected cervical lesions. Metrizamide (Amipaque) was used in 44 cases and Iohexo (Omnipaque) in 13. Visualization was good to excellent in all cases. Complications were headaches in 3, vomiting in 1 and seizures in another. In the latter patient, the contrast passed intracranially during the Trendelenburg tilting for thoracic visualisation. Twice some contrast was injected epidurally without complication. However, this comprised visualisation. Extreme care was taken in proper patient hydration, gentle motion in the procedure and the 15-30 degree head up position for 24 hours post-myelogram. There is advantageous ease of performance, rarity of complications, outpatient performance and lack of necessity for fluoroscopy in areas where this is not available. It is advised for use in developing territories where the common problem of back pain and suspected lower spinal lesions can be more easily investigates (AU)