J Neurosurg 48:1038-1041, 1978
A new combined neurosurgical headholder and cassette changer for intraoperative serial angiography Technical note
DWIGHT PARKINSON, M . D . , JULES LEGAL, ARTHUR F. HOLLOWAY, PH.D., RICHARD J. WALTON, R.T., ROBERT R. LAFRANCE, DOUGLAS W. MACEWAN, M . D . , AND JANE JOHNSON, M . D .
Section of Neurological Surgery, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada v, A new apparatus that can provide immediate intraoperative x-ray study or serial angiography is described. KEY WORDS cassette changer 9
intraoperative serial angiography 9 headholder 9 9 cranial vascular surgery 9 cervical vascular surgery
NTRAOPERATIVE angiography is a neurosurgical luxury usually obtainable only at the expense of considerable time and disturbance in repositioning and redraping of the patient. For serial angiography, it is usually necessary to move the patient to the angiography room and then back with his open wound. Thus, the surgeon often foregoes intraoperative angiography and the valuable information it might give him. The combined neurosurgical headholder and cassette holder described here was first designed and constructed to provide intraoperative serial angiography as an aid in the surgery of carotid cavernous fistulas.1 With these extremely high-flow lesions, single-film operative angiography was never sufficient. Once the apparatus was available, the indications for its use expanded immediately. The neurosurgeons' greatest and most frequent need for intraoperative serial angiography arises when dealing with arteriovenous ]038
malformations. Single-film exposure rarely captures the column of contrast material at the point where it gives the desired information. In fact, such a single exposure may be misleading, showing vessels only to the point of dispersal into a fistula or just beyond. With serial angiography the surgeon is assured of the complete removal or alternatively the exact location of any residual connections) '8 The picture quality is equivalent to those taken in the X-ray Department (Fig. 1). During the surgery of saccular aneurysms, we take a preliminary angiogram on the operating table to verify the identity and projection of the aneurysm in that view. Another angiogram is then taken immediately after the clip is fixed. Thus the surgeon is aware of any compromise of an adjacent vessel or of the incomplete obliteration of the aneurysm in sufficient time to reposition the clip. Interestingly, although a few in this short series of cases developed severe spasm in the
J. Neurosurg. / Volume 48 /June, 1978
Intraoperative angiography: A new device
FIG. 1. The fourth in a series of six intraoperative serial angiograms taken at l-second intervals during the removal of a large AVM demonstrating a residual segment of fistula just beneath the wire circle marker.
postoperative period, none of these cases demonstrated any spasm in the immediate postclipping angiograms. If embolization is being used as an adjunct to extirpation of a vascular meningioma or arteriovenous (AV) fistula, intraoperative serial angiography is a fascinating aid. Our experience has been that far more injections of emboli are required than one would anticipate. When the patient is placed high enough so that the neck comes over the cassette changer, serial angiography may be used during such procedures as repair of AV fistulas of the vertebral artery or the carotid artery in the neck.
Description of Apparatus The apparatus was constructed in the Physics L a b o r a t o r y of the Cancer Research Institution at the Health Sciences Centre, Faculty of Medicine of the University of J. Neurosurg. / Volume 48 / June, 1978
Manitoba. The headholder had to meet two requirements: 1) to encircle the mass representing the cassette holder, and 2) to provide a wide range of positioning. The cassette changer was designed primarily under the direction of one of us (D. W. MacE.). The small cassettes, only 0.8 cm thick, were especially constructed of milled magnesium with lead backing. The apparatus provides from one to six exposures. The timing device will trigger the injection and the settings provide automatically any predetermined interval before the first exposure and each subsequent exposure. The surgeon thus has an unlimited range of control over the exposure spectrum. The cassette changer may be left parallel to the floor while the headholder turns to any desired position or the changer m a y be tilted with the headholder or independently of the headholder (Figs. 2-4). Originally, we tried to move the cassette holder so as to have straight ]039
D. Parkinson, et al.
Fro. 2. View from head of table. Left: Cassette changer parallel, headholder rotated 30 ~ to the right. Right: Head fixed in head holder. The swinging arms can be seen in place beneath the cassette holder; these will hold drapes out for ease of changing the cassette.
anteroposterior or lateral views with each head position. We now usually leave the cassette holder parallel to the floor, having found that the resulting oblique views are just as informative and, in fact, often m o r e informative than the straight views. The cassette changer should be covered with polyethylene before the head is positioned, as any blood or saline leaking into the changer will cause the cassettes to stick.
Reloading requires about 6 seconds. There is a swinging a r m beneath the apparatus to hold out the drapes, providing access for the radiologist to reload (Fig. 2 right). Thus, without disturbing the draping, a single exposure or a series m a y be taken as easily as a photograph taken through the operating microscope. The only inconvenience is the necessity to stand behind the protective shield during the actual exposure.
FIG. 3. Side view, showing apparatus tilted up (left), and down (right). 1040
J. Neurosurg. / Volume 48 / June, 1978
Intraoperative angiography: A new device
FIG. 4. View from above with headholder rotated on vertical axis 30 ~ to the right.
The headholder itself provides a greater range, ease, and firmness of positioning than any holder we have yet encountered, requiring only finger tip control to effect a change in any plane. The coarse horizontal gears on the rod holding the pins provide an instantaneous positioning, and the threading within the heads of the pins is so finely machined that fingertip twisting provides absolute skull fixation. Technique Our technique has been to catheterize the temporal artery at the operative site. With a little practice this becomes a simple and rapid procedure. The catheter is then connected through a three-way stopcock to a pressurized continuous drip until an a n g i o g r a m is desired; the anesthetist then merely switches the stopcock to the line of the power injector. This suffices in nearly all cases (Fig. 1). We have used a retrograde brachial injection for the vertebral system or the right carotid artery, and rarely have we found it necessary to surgically expose the external carotid. We have never used an indwelling cannula in the common or the internal carotid arteries for fear of thrombi or emboli.
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Because of its superb maneuverability and firmness of positioning we use the headholder on virtually every c r a n i o t o m y even if intraoperative angiography is not planned. However, we now routinely take a single film during the closure of every c r a n i o t o m y , thus assuring the surgeon t h a t t h e r e are no overlooked cottonoids or such in the wound. Although at the m o m e n t we only use a single overhead x-ray tube, stereoscopic views could be provided by the simple addition of the double-headed tube used in regular angiography, thus providing stereoscopic views with a single injection? '5 References 1. Parkinson D: Carotid cavernous fistula: direct repair with preservation of the carotid artery. Technical note. J Neurosurg 38:99-106, 1973 2. Parkinson D: Cerebral arteriovenous aneurysms; surgical management. Can J Surg 1:313-325, 1958 3. Parkinson D: Rapid serial simultaneous biplane stereoscopic angiography; an aid in the surgical management of cerebral arteriovenous malformations. Clin Neurosurg 16:179-184, 1969 4. Parkinson D, Childe AE" Carotid angiography. A clinical evaluation of 200 consecutive cases. Can Med Assoc J 72:571-575, 1955 5. Parkinson D, MacPherson RA, Childe AE, et al: Routine simultaneous bi-plane stereoscopic angiography. J Can Assoc Radiol 18:371-376, 1967
This paper was presented in part at the Symposium on Intracranial Aneurysm Surgery, Bad Nauheim, Germany, in March, 1977. Address reprint requests to: Dwight Parkinson, M.D., Section of Neurosurgery, Department of Surgery, S 105 Medical Services Building, 770 Bannatyne Avenue, Winnipeg, Manitoba R3E OW3, Canada.