Neurosurgical treatment of periodic migrainous neuralgia

S88 128.Poster NEUROSURGICAL TREATMENT OF PERIODIC YI;RAINOUS i Saturday NEURALGIA. w. I-1.sweet, Neurosurgical Service, Cascade 36 Massachusetts Generdl Hospital, Boston, MA 02114 For the few patients whose attacks become not only refractory to medical regimes but as well persistent without remissions, several types of surgical neural lesions have proven helpful. Impulses concerned with these pains may traverse afferent pathways either in Cranial nerve V or in n. intermedius, IX & X or both routes. Although the trigeminal pathway is more frequently involved, its interruption may provoke a state of painful denervation even when touch is conserved. This is less likely to occur when the VII, IX, X pathways are divided. We test the effect of a temporary denervation before resorting to a more permanent type of procedure. For the trigeminal nerve we have used one or more retroqasserian lidocaine blocks. If these yield encouraging results we now use radiofrequency heating of the 1st and 2nd division rootlets. Alternatively we try the peripheral denervation of greater and lesser superficial If this yields relief lasting months we petrosal neurectomy. may proceed to rhizotomy of nervus intermedius, IX and the upper fibers of X or to a tractotomy of the descending Transection of this pathway at or a cephalic pain pathway. little below the level of the obex divides the pain fibers in The results after the following intermedius IX & X. VI nervus numbers of operations will be described: petrosal neurectomy of nervus intermedius IX & X 3, V peripheral 24, section lidocaine 26, retroqasserian RF neurectomy 7, retroqasserian tractotomy 2. 3, bulbar lesion 21, open V rhizotomy MECHANISMS IN C@!i'?ON MIGPAINT: ’ 129 Poster K. Jensen and J. Olesen, Department of Neurolq, Copenhaqen! Saturday 1 County Hospital in Gen'cofte,2900 Hellerup, Denmark. Cascade 37 L._ ___J We have previously shown normal cerebral bled flow during rniqraineattacks and tender trigger points in chewing muscles as a possible cause of the pain. The aim of the present study was to measure blocd flow intempxalmuscles durinq and outside of commn rriqraineattacks. Methods: The local 133-Xenon washout technique with bilateral simultaneous registration was applied. Averaqe EMG was recorded with bipolar surface electrodes. Individual maximxn m activity was recorded during tooth-clenching,whereafter patients were asked to relax with their eyes closed while blood flow was measured. Results: 8 minutes after the Xenon-injection resting blood flow averaged 5 ml/l00 q/min. During attacks as well as on days without headache there was no significant side to side difference in the 9 patients, who had unilateral attacks. During attacks a rredianincrease in restinu blood flow of approximately 40% was observed. After measurerrentsof resting blood flow one group of patients were asked to perfo& 2 Ininutesof chewing, reaching an EMG amplitude of approtiately 50% of the individual rmximum. This led to a 350% increase of blood flow durinq attacks as well as on days without headache. Another group of patients were asked to perform 2 minutes of tooth-clenching at a constant EFIGmplitude of appr. 30% of the individual mximmn. This procedure led to a 250% increase in blood flow during attacks as well as on days without headache. Conclusion: The present study provides evidence aqainst the following causes of ccxtmm lriqrainepain: 1) Tonic mscle contraction with ischezia. 2) Spasm of thetemporalartery. 3) Extracranial vasodilatation with yralysis of the vascular mth muscle. EYXT~CRANIALPAIN