SURGICAL TREATMENT OF PARTIAL EXTRALUMINAL OCCLUSION OF FIRST PART OF VERTEBRAL ARTERY S. ALLAN HURVITZ, M.D., F.A.C.A. This report presents the clinical concept of hindbrain ischemia due to partial extraluminal occlusion of a segment of the first part of the vertebral artery. My first report on this subject presented 23 patients operated upon between October 11, 1974, and July 25, 1975.~ This second report presents an additional 8 patients operated upon between July 28, 1975, and October 3, 1975. Partial extraluminal occlusion of a segment of the first part of the vertebral artery is caused by kinking of the proximal vertebral artery, or by an alteration of the normal take-off angle of vertebral from subclavian artery by upward arching of the subclavian artery, with or without elongation of the vertebral artery (Fig. 1). Partial extraluminal occlusion can also be caused by fibrous tissue arising from the supra-pleural membrane, by perivascular fibrosis, or by other tissue structures. Upward arching of left subclavian artery can be so extreme as to cause kink occlusion of the subclavian artery itself. Upward arching of the subclavian artery is caused by anatomic changes occurring with the aging process. z CLINICAL MATERIAL There were 31 patients with severe symptoms of hindbrain ischemia who had an operation for correction of partial extraluminal occlusion of the proximal vertebral artery between October 11, 1974, and October 3, 1975. Seven of the 31 patients had staged bilateral procedures. There were 19 females and 12 male patients ranging in age from 25 to 90 years; 20 patients were over 60 years of age and 3 patients were under 33 years of age. Aortic arch angiography with visualization of the neck vessels through the transfemoral route was performed pre-operatively on all patients by a radiologist. Seventeen patients had post-operative arch angiograms which showed patent operated vertebral arteries in all. For 3 months to 15 years pre-operatively, 28 of the 31 patients had a disorder of equilibrium with an unsteady gait. Equilibrium was markedly improved after operation in all of these patients. An acute hemi-paresis resolved post-operatively in 4 patients. One patient’s left hemi-paresis resolved in the presence of 90% stenosis of the right internal carotid artery. A 58 year old male became hemiplegic on the right in January, 1975. Five months after the stroke he had difficulty walking with a cane; he Address reprint requests to Dr. Hurvitz, Vertebral Artery Institute, 10921 Wilshire Blvd., Suite 907, Los Angeles, California 90024. Read at the Twenty-second Annual Meeting of the American College of Angiology, Palm Springs, California, January 7, 1976. 223 224 ......-..-. FIG. 1. (Patient 20.) (A) Pre-operative angiogram shows upward arching of the subclavian and kinking of the proximal vertebral artery just beyond its origin. (B) Post-operative study shows a patent proximal vertebral artery. depressed, unable to recognize relatives, and had an expressive dysphasia. A pre-operative angiogram showed partial occlusion of the proximal right vertebral artery and complete occlusion of the left internal carotid artery. An operation on the right vertebral artery was performed on May 7, 1975. Cur- was 225 rently the patient is able to walk without a cane. He recognizes his relatives and friends, understands everything spoken, is without depression, and the expressive dysphasia has improved. For 7 years a 53 year old female had a progression of a disorder of equilibrium, dizziness, dysphagia, slurred speech, headache, decreased mental function, diplopia and blurred vision, slight motor weakness on the left, disorder of urinary bladder control, and constipation. She had an elongated first part of left vertebral artery with severe kinking of the vessel, without upward arching of the subclavian artery (Fig. 2). Following an operation on the left vertebral artery on April 25, 1975, the patient’s symptoms markedly improved. A 76 year old male for 10 years had a progression of a disturbed equilibrium, dizziness, slurred speech, dysphagia and headache. He required assistance to walk, and intermittently aspirated liquids. He was unable to hold a pen to write. Bilateral staged operations on the vertebral arteries were performed. At present he is able to walk with a cane, and hold a pen and write. Dysphagia and headache are gone, and his speaking ability has improved. Three patients, aged 25, 27 and 32, had a congenital type of partial extraluminal occlusion of the left vertebral artery. Two had fibrous tissue from the supra-pleural membrane compressing the proximal 1 centimeter of the vertebral artery (Fig. 3). The third had fibromuscular tissue compressing the same segment of vertebral artery. In this patient, microscopic study of the tissue which compressed the proximal vertebral artery showed filaments of skeletal muscle in a connective tissue stroma. A 49 year old female with a 6 month history of a disorder of equilibrium, slurred speech, headache, dizziness, and the loss of the ability to knit was operated upon on March 27, 1975. She is not included among the 31 patients because the pre-operative angiograms showed complete occlusion, non-visualization, of the left vertebral artery. At operation the proximal left vertebral artery was found to be obliterated, represented by a few fibrous strands of tissue, located 2 centimeters medial to the thyrocervical trunk. The thyrocervical trunk was compressed by fascial bands. There was extraluminal occlusion of the costocervical trunk due to perivascular fibrosis and upward arching of the subclavian artery. The costocervical and thyrocervical trunks were mobilized and freed of compressing tissue. The costocervical trunk measured 3 millimeters in diameter. The internal mammary and suprascapular arteries were ligated in continuity. An operative arteriogram was obtained which demonstrated filling of the second part of the vertebral artery by collateral flow through the deep cervical branch of the costocervical trunk (Fig. 4). Post-operatively the patient showed marked improvement. There was no mortality and no significant morbidity in this series. An operation through a lower neck incision is well tolerated by elderly patients with heart disease. An incision is made above the medial third of the clavicle. The first part of the vertebral artery is mobilized as far distally as possible and is freed from all compressing and adherent tissue.1 FIG. 2. (Patient 12.) (A) Pre-operative angiogram shows a kink of the first part of an elongated left vertebral artery. (B) Post-operative angiogram shows a straightened first part of verbetral artery without a kink. 226 227 FIG. 3. (Patient 17.) (A) Pre-operative subtraction angiogram shows non-filling of the proximal 1 cm of left vertebral artery due to compressing congenital fibrous bands. (B) Post-operative selective subclavian arteriogram shows a patent proximal vertebral artery. 228 FIG. 4. Operative arteriogram shows filling of the second part of the left vertebral artery by collateral flow from the deep cervical branch of the costocervical trunk in a patient with fibrous obliteration of the proximal left vertebral artery. Operative arteriogram was done following the surgical correction of extraluminal occlusion of the left costocervical trunk. DISCUSSION Decreased perfusion through either vertebral artery caused by partial extraluminal occlusion, with or without carotid bifurcation arteriosclerotic occlusive disease, can produce symptoms of hindbrain ischemia. The vertebral artery supplies the brainstem and the inferior aspect of the cerebellum. The symptoms of hindbrain ischemia include: disorder of equilibrium with an unsteady gait, difficulty balancing on 1 foot, dizziness in the upright position, difficulty in writing and knitting, slurred speech, headache, dysphagia, vertigo, tinnitus, drop attack, drowsiness, excessive sleeping, decrease of mental capacities, diplopia, blurred vision, syncopal attacks, hemiparesis, hypesthesia, and tremor. Most of these symptoms are partially reversible after an operation to correct a partially occluded vertebral artery, even with a 10 to 15 year progressive history. Poiseuille’s Law states that volumetric flow rate is proportional to the fourth power of the diameter of a circular tube. In other words, increasing the diameter of a narrowed vertebral artery 10 times, increases blood flow 10,000 times. 229 SUMMARY This report presents the clinical concept of hindbrain ischemia due to partial extraluminal occlusion of a segment of the first part of the vertebral artery, and submits a definite method of surgical treatment. Thirty one patients with vertebral artery insufficiency are presented who had operations with striking post-operative symptomatic improvement. Operative selection of patients is dependent on aortic arch angiography with visualization of the neck vessels. There was no mortality and no significant morbidity in this series. S. Allan Hurvitz, M.D., F.A.C.A. Vertebral Artery Institute 10921 Wilshire Boulevard Suite 907 Los Angeles, California 90024 REFERENCE 1. Hurvitz, S. A.: Surgical treatment of partial extraluminal occlusion of vertebral artery. Surg. Gynecol. Obstet. In press.