The following must be explained in the technique of rhizotomy: first of all, laminectomy must be carried out. The skin over the vertebrae is reflected, along with the back musculature, thus revealing the arch of the vertebrae. In this way we have access to the vertebral canal, which contains the dural sack. After opening the latter with a longitudinal incision and after section of the arachnoid, cerebrospinal fluid runs out, the spinal cord sags anteriorally, and the posterior roots are more or less obvious. We search out the appropriate ones and lift them into the operative field. The accompanying vessel is freed up (Plate ///) and the root is sharply cut through. The dura is then sewn. The incision is closed with interrupted stitches in three or four layers. The patient can be ambulated in 7—21 days, according to the extent of the operation on the spinal column.
Section of sensory roots can be carried out wherever the disease process involves a relatively small area and cannot be dealt with per se. Examples of this are malignant tumours, unilaterally placed in the neck, tumours of the thoracic wall, or at the origins of the extremities (axilla and groin). With pain originating from organs in the thoracic or abdominal cavities, e. g. malignant neoplasm of the pleura, metastatic growths in the vertebrae, abdominal cancer invading the posterior abdominal wall, inoperable carcinoma of the appendix, urinary bladder or uterus, such operations are of advantage. Root pain resulting from arachnoiditis inside the spinal canal can also be dealt with in this way. It has been stated above that such procedures may result in complications as far as the extremities are concerned; we do not recommend rhizotomy and rather incline to anterolateral chordotomy (see B, 3 a). Section of the sensory roots has assumed new significance in the wider use of this procedure for intervertebral discopathy. The blame may be put on a fashionable enthusiasm for this operation, where more than once the segment of disc which was supposed to be compressing the root has not been found on operation. The surgeon, in an attempt to relieve the patient of pain which he really felt, performs a root section, and some surgeons, such as Petit-Dutaillis, always complete operations on discs with rhizotomy.