THE ANKLE CLONUS TEST FOR ASSESSMENT OF THE INTEGRITY OF THE SPINAL-CORD DURING OPERATIONS FOR SCOLIOSIS

The ankle clonus test, a method for evaluating the integrity of the sp inal cord during operations for scoliosis, is predicated on the findin g that patients recovering from general anesthesia normally have tempo rary ankle clonus bilaterally An absence of transient ankle clonus has been shown to indicate neurological compromise. The test was performe d for 1006 patients who were being managed with spinal arthrodesis and instrumentation and 115 control patients who had an operation under g eneral anesthesia because of a condition that was unrelated to the spi ne, The six patients in whom a neurological deficit developed all had had a so-called positive result on the ankle clonus test (that is, an absence of transient ankle clonus), There were no false-negative resul ts and three false-positive results; the test therefore had a sensitiv ity of 100 per cent and a specificity of 99.7 per cent, The ankle clon us test was found to be more accurate than the wake-up test and monito ring of somatosensory evoked potentials for predicting neurological co mpromise.