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Intra Venous Digital Subtraction Angiography for Patients with Positional Nystagmus
Auris·Nasus·Larynx (Tokyo) 13 (SuppJ. II), S 113-S 121, 1986
INTRA VENOUS DIGITAL SUBTRACTION ANGIOGRAPHY FOR PATIENTS WITH POSITIONAL NYSTAGMUS Toru INAMORI, M.D., Hirofumi MACHIZUKA, M.D., Takeo KUMOI, M.D., and Yukio TAKAYASU, M.D. Department of Otolaryngology, Hyogo College of Medicine, Hyogo, Japan
Thirty cases of intractable positional vertigo were studied by means of digital subtraction angiography (DSA). Benign paroxysmal positional vertigo was not included. DSA allows real time digital subtraction of X-ray transmission data using an image intensifier and television system. Intravenous DSA (IV DSA) was used to compare blood vessel flow in the right and left vertebral arteries. Abnormal findings Were noted in 27 patients, with 10 being affected on the left side, 7 on the right, and 10 bilaterally. Twenty-three patients had slight stenosis, and bending and kinking were observed in 17. DSA results were related to the 6 established types of positional nystagmus. DSA is, therefore, considered to be an important tool in the diagnosis and treatment of positional vertigo. There are an increasing number of patients visiting otolaryngology clinics whose chief complaint is vertigo. The diagnosis and analysis of vertigo has become more precise with the use of the computer. Also with the development of antivertigo drugs, we have been able to treat many patients more effectively. However, in many cases the cause of vertigo is not always clear. If persistent vertigo is present, regardless of the treatment, it is necessary to ascertain the cause. Today, besides the equilibrium examination, the CT scan is most commonly applied for examination. But, even the CT scan cannot always reveal abnormal findings. In our research we have applied digital subtraction angiography (DSA) to such patients. One of the advantages' of DSA is that angiography can be performed after intravenous administration of the contrast medium. Although spatial resolution with this method is inferior, the contrast resolution is excellent and DSA can be performed simply and noninvasively (CHRISTENSEN et al., 1980; HESSELINK et al., 1984). Doppler sonography has been used to determine whether Received for publication August 14, 1986 S 113
T. INAMORI et af.
S 114
a vertebral artery is open or occlusive, but this technique is less reliable for vertebral stenosis and gives no information about the basilar artery. We were able to find a considerable number of abnormalities in many cases. SUBJECTS AND METHODS
Thirty patients with intractable positional vertigo spells -except benign paroxysmal positional vertigo-, resistant to treatment, with some signs of CNS disturbance, but no significant findings with the CT scan, and who had requested further study were referred for DSA testing. DSA was performed using a Shimazu 100 digital angiographic system. With this system the X-ray passing through the body is amplified and converted in an image intensifier to an electric signal and recorded with a TV camera. After logarithmic amplification, the signal is converted to digital information by the AID converter, and sent to a processor which incorporates a microcomputer. The A/D conversion is performed on a matrix of 512 x 512 and has gray scales which are 9 bits deep. In the processor, 2---4 frames of mask images are added and the information is stored in one of the digital frame memories. After the addition of contrast medium and, after subtraction from the mask images, these signals are transmitted to another digital frame memory. Information from the two frame memories then passes through the digital/analog converter and image processing units, and is displayed on TV monitors as final processed images. After processing, the images are recorded on a video disk recorder, a video tape recorder, and the X-ray
I X·ray
Tube L:J
I
c:Lr:J
Shutter
Fig. 1.
~
Block diagram of DSA.
IV DSA AND POSITIONAL NYSTAGMUS
S 115
films (Fig. I). A 5 French Katzen Digiflex (Meditec®) catheter was introduced into an antecubital vein and positioned in the superior vena cava with fluoroscopic monitoring. Then 25-40 ml of Urografin-76 was injected at a rate of 15-20 ml/sec. Routine anteroposterior views were taken with and without the patient's head turned 45° to the right and left 45° to the left of the cervical vertebral arteries and AP and lateral views were taken of the basilar artery. The DSA imaging was performed on 30 patients-12 males and 18 females (averaging 52.7 years in age). The images of the vertebral and basilar arteries were evaluated for each patient. Representative figure of actual DSA is shown in Fig. 2. The location of the vessel stenosis, its grade and bending or kinking were analyzed. Then the DSA results were compared with the patient's equilibrium examination. In order to clarify the location of the vessels' stenosis, the vertebral artery area was divided into three parts. The first part (1) was designated as the region extending from its source to the level of bifurcation of the carotid artery. The second part (2) was from the level of bifurcation of the carotid artery to the magnum. The third aprt (3) was the intracranial vertebral artery. And the grade of stenosis was categorized as complete obstruction (a), severe stenosis (b), and mild stenosis (c). For some cases the measurement of the rate of blood
Fig. 2.
Representative figure of actual DSA.
S'116
T. INAMORI et
at.
flow was also calculated from the digital information obtained from DSA. Then the existence and cause of meandering, bending, and kinking were investigated. RESULTS
DSA studies resulted in 3 cases with normal findings (10%) and 27 cases with abnormal findings (90%). If the results of IV DSA are considered separately there are more than 27 abnormalities, since there are more than two positions in one patient (Table 1).
A.
Location of stenosis In 7 cases stenosis was on the right, in 10 on the left, and in 10 on both sides. Stenosis from the source of the vertebral artery to the level of bifurcation of the carotid artery was found in 14 cases. In 13 cases the entire vertebral artery was involved. Extracranial vertebral arteries with stenosis were found in 3 cases, and intracranial vertebral arteries with stenosis in 3. From the level of bifurcation of the carotid artery to the intracranial vertebral artery there was only 1 case. Table 1. Summary of DSA results of all 30 patients. Normal Abnormal
(cases)
(%)
3 27
10.0 90.0
10
33.3
7 10
23.3 33.3
Side Bilateral Unilateral Right Left Location Entire vertebral region Part of vertebral region Inf. half of extracranial Extracranial Intracranial Sup. half of extracranial and intracranial
13
43.3
14 3 3 1
46.7 10.0 10.0 3.3
Grade Complete obstruction Severe stenosis Mild stenosis
4 23
13.3
Bending No meandering, bending, nor kinking Meandering, bending, and kinking due to osteophytes Meandering, bending, and kinking due to Power's syn.
10
33.3
11 6
36.7 20.2
Meandering, bending, and kinking due to atherosclerosis
14
46.2
3.3 73.3
IV DSA AND POSITIONAL NYSTAGMUS
S 117
B.
Grade of stenosis One side of complete obstruction was found in one case, the severe grade of stenosis in 4 and the mild grade in 23. Using the method described in Fig. 3, blood flows of the vertebral artery in 10 cases were measured. In 7 out of 10 cases the rate on the one side was more than twice the rate on the another side, and in case 7 the rate measured in the right vertebral artery decreased from 67.5 mljmin to 42.5 mljmin, as the patient turned his neck to the left. Also, a severe grade of stenosis was found in the left vertebral artery of a 54-year-old female patient with a normal rate of
Density
:--lIt--: : I
I
A
B
Time
Fig. 3. Schematic illustration of blood flow measurement. Set the measuring points of ROI (region of interest) to 1 and 2, then draw two time-density curves with their differential curves. The microcomputer finds the turning points of A and B from two differential curves, and also measures the distance between 1 and 2, and the diameter of blood vessel in 1 and 2 at the time of A and B. Thus, the amount of blood flow can be estimated by dividing the value of volume between 1 and 2 by LIt. 1', differential curve of 1; 2", differential curve of 2. Table 2. The data ot blood flow rate in vertebral artery (VBF) measure in 10 cases. No.
Case
Age
Sex
1 2 3 4 5 6 7
A.M. A.U. K.M. Y.!. E.K. H.H. C.H.
59 52 72 61 66 57 59
M M M F M M F
8 9 10
S.N. M.N. A.I.
37 50 50
F M M
* Lt rotation.
VBF (ml/min) R
L
52.5 46.3 35.2 108 21. 2 101 67.5 42.5 196 126 263
169 51. 9 10.2 80.1 215 44.5 49.8 68.4* *70 136 51. 8
S 118
T. INAMORI et al.
129.0 ml/min in the right position and a rate of 5.13 ml/min in the left position (Table 2).
Existence of meandering, bending, and kinking For 17 cases in which meandering, bending, or kinking was found, I I were diagnosed as osteophytes on cervical vertebrae, and 6 cases as Power's syndrome (POWERS et al., 1961) or abnormal irritation of the cervical sympathetic nerve. C.
D.
DSA results and equilibrium examination With equilibrium examination gaze, nystagmus was found in 12 cases and spontaneous nystagmus in 15 cases. In 6 cases, gaze nystagmus was in one direction (right or left), in 2 it was in two directions (rgiht and left) and in one case it was in three directions (right, left, and up). In 7, spontaneous nystagmus was in one direction and in 8 it was in two directions. Since positional vertigo was the main complaint of the patients in this study, positional nystagmus naturally occurred in all 20. Positional nystagmus test was performed on the bed in supine position. Nine cases had nystagmus which was changing but always in a downward direction; that is, nystagmus elicited to the same direction as the recumbent or neck torsion side. Three cases had nystagmus changing in an upward direction (direction changing upward nystagmus), that is, nystagmus elicited to the opposite direction to recumbent or neck torsion side. Twelve cases had only one directional downward nystagmus. One case had direction fixed horizontal nystagmus, and one had direction fixed vertical nystagmus. Three had horizontal nystagmus in their body sagittal plane. DISCUSSION
Vertigo that is dependent on the position of the patient's head is called positional vertigo. Nystagmus produced by torsion of the neck may be tested for by either turning the neck on the body or by holding the head stationary and turning the body from side to side. About 80-90% of positional nystagmus is the benign positional type. The benign paroxysmal positional vertigo condition is produced when the patient's head is placed in a certain position. This vertigo can be provoked by the DIX-HALLPIKE (1952) provocation test when the affected ear is down. It has a short latency period and is shortly adaptable and easily fatigable. Also its nystagmus is chiefly rotatory in nature and it usually stops in 10-15 sec, and lasts a shorter time with each test until it cannot be produced by position changes. SCHUKNECHT and RUBY (1973) postulated that this vertigo which they termed "cupulo-lithiasis," is due to the adherence of degenerated otoliths to the cupula of the posterior semicircular canal, which changes the specific gravity of the cupula and causes gravity to affect the cupula.
IV DSA AND POSITIONAL NYSTAGMUS
S 119
The disease may persist for weeks or months and then disappear forever, or may recur spontaneously many months or years later. Occasionally it is persistent and continues unchanged for years. It is important to investigate the character of positional nystagmus when a patient complains of vertigo for a long time in spite of treatment. Because of vertebral stenosis, infarction or tumors of the brain stem, cerebellar disease, or various neck disorders, another type-malignant positional nystagmus-may occur. The malignant positional nystagmus, in contrast to the benign type, has no period of latency, is nonfatigable and lacks rotatory component, usually in the horizontal plane but occasionally in the oblique or vertical plane. The nystagmus may change directions during the test position. In a discussion of vertebro-basilar insufficiency, the two major arteries involved are the anterior inferior cerebellar artery, which is a branch of the basilar artere, and the posterior inferior cerebellar artery, which is a branch of the vertebral artery. Atherosclerosis is probably the most common cause of vascular insufficiency. Extrinsic pressure on the arteries that supply the inner ear and brainstem can cause vertebro-basilar insufficiency. These problems occur most often in the neck, where the vertebral vessels pass through the transverse foramina. Osteophytic spurs due to arthritis, a cervical rib, fibrous and muscular bands or congenital anomalies of the cervical vertebrae may compress the vertebral arteries. Three basic mechanisms have been proposed to explain the occurrence of cervical vertigo. These are disturbed vertebro-basilar insufficiency (HUTCHINSON, 1956), involvement of the sympathetic vertebral plexus (WELDHAGEN, 1958), and involvement of the sensory afferent fibers in the neck muscle (COPE and RYAN, 1959). Treatment shouldn't be instituted until the diagnosis and associated disorders are clearly established. An otoneurologic consultation and special studies, including IV DSA are necessary. Intravenous DSA has some advantages over selective vertebral arteriography. There is minimal risk of stroke, and the study can be done on an outpatient basis with immediate calculation of the rate of blood flow in any vessels. Since DSA studies are conducted in real time on the monitor screen, we can observe the change in blood flow rate due to vessel compression by torsion of the patient's neck, and his positional nystagmus. In this study the DSA results were compared to the patient's equilibrium examination, but disappointingly no correlation could be found. It is difficult to determine the side or location of stenosis from the nystagmus findings. The DSA examination must be conducted immediately to determine the cause of nystagmus, but considering abnormalities fO:.Jnd in DSA as the direct cause of vertigo is insufficient. Various forms of examination must be used to determine the cause. However, we have two cases who had been diagnosed as Power's syndrome, and patients were treated successfully by performing a
S 120
T. INAMORI et
at.
stellate gangling block. For this reason, in these 2 cases abnormal stimulation of the cervical sympathetic nerve causes stenosis of the vertebral artery which leads to insufficiency when the direction of the head is changed, and vertigo was experienced by them when there was stenosis of a blood vessel. It should be emphasized from our present study that the direction of positional nystagmus is not always correlative with the stenotic region of the vertebrobasilar system and performing DSA is a method of choice to reveal the stenotic lesion. CONCLUSION
Intravenous DSA studies were performed in 30 cases with intractable positional nystagmus. Abnormalities were found in 27 cases. The following results were obtained from this study of positional nystagmus and DSA. 1. Partial stenosis of the vertebral region occurred in 14 cases. Stenosis of the entire vertebral region occurred in 13 cases. Many of the former showed changes in direction of downward nystagmus and many of the latter were one directional in downward nystagmus. 2. Complete obstruction of the vertebral artery was found in 1 case, severe stenosis in 4 cases and mild stenosis in 23 cases. 3. Meandering, bending, and kinking of the vertebral artery occurred in 17 cases. In many of these cases nystagmus was downward in one direction. 4. Meandering, bending, and kinking of the vertebral artery due to osteophytes occurred in 11 cases. Three of these cases showed directional changing nystagmus and 3 of these cases showed one directional down beat nystagmus. Power's syndrome was present in 6 cases and atherosclerosis in 14 cases. 5. The blood flow of the bilateral vertebral artery was measured. DSA studies are important and useful in determining the cause of positional nystagmus. REFERENCES CHRISTENSEN, P.C., ORITT, T.W., FISHER, H.D., FROST, M.M., NUDELMAN, S., and ROEHRIG, H.: Intravenous angiography using digital video subtraction. AJR 135: 1145-1152, 1980. COPE, S., and RYAN, G.M.S.: Cervical and otolith vertigo. J. Laryngol.73: 113-120, 1959. DIX, M.R., and HALLPIKE, C.S.: The pathology symptomatology & diagnosis of certain common disorders of the vestibular system. Proc. R. Soc. Med. 45: 15-28, 1952. HESSELINK, 1.R., TERESI, L.M., DAVIS, K.R., and TAVERAS, 1.M.: Intravenous digital subtraction angiography of arteriosclerotic vertebrobasilar disease. AJR 142: 255-260, 1984. HUTCHINSON, E.C., and YATES, P.O.: The cervical portion of the vertebral artery: A clinicopathological study. Brain 79: 319-331, 1956. NAGASHIMA, C.: Surgical treatment of vertebral artery insufficiency caused by cervical spondylosis. J. Neurosurg. 32: 512-520, 1970.
IV DSA AND POSITIONAL NYSTAGMUS
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POWERS, S.R., DRISLANE, T.H., and NEVINS, S.: Intermittent vertebral artery compression : A new syndrome. Surgery 49 : 257-264, 1961. SCHUKNECHT, H.F.: Cupulolithiasis. Arch. Otolaryngol. 90: 113-126, 1969. SCHUKNECHT, H.F., and RUBY, R.R.: Cupulolithiasis. Adv. Otorhinolaryngol. 20: 434-443, 1973. WELDHAGEN, F.: Ein KIinischer Beitrag zur Pathogenese Hydropischer Innenohyprozette. Acta Otolaryngol. 49: 256-268, 1958.
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Request reprints to : Dr. T. Inamori. Department of Otolaryngology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663, Japan
INTRA VENOUS DIGITAL SUBTRACTION ANGIOGRAPHY FOR PATIENTS WITH POSITIONAL NYSTAGMUS Toru INAMORI, M.D., Hirofumi MACHIZUKA, M.D., Takeo KUMOI, M.D., and Yukio TAKAYASU, M.D. Department of Otolaryngology, Hyogo College of Medicine, Hyogo, Japan
Thirty cases of intractable positional vertigo were studied by means of digital subtraction angiography (DSA). Benign paroxysmal positional vertigo was not included. DSA allows real time digital subtraction of X-ray transmission data using an image intensifier and television system. Intravenous DSA (IV DSA) was used to compare blood vessel flow in the right and left vertebral arteries. Abnormal findings Were noted in 27 patients, with 10 being affected on the left side, 7 on the right, and 10 bilaterally. Twenty-three patients had slight stenosis, and bending and kinking were observed in 17. DSA results were related to the 6 established types of positional nystagmus. DSA is, therefore, considered to be an important tool in the diagnosis and treatment of positional vertigo. There are an increasing number of patients visiting otolaryngology clinics whose chief complaint is vertigo. The diagnosis and analysis of vertigo has become more precise with the use of the computer. Also with the development of antivertigo drugs, we have been able to treat many patients more effectively. However, in many cases the cause of vertigo is not always clear. If persistent vertigo is present, regardless of the treatment, it is necessary to ascertain the cause. Today, besides the equilibrium examination, the CT scan is most commonly applied for examination. But, even the CT scan cannot always reveal abnormal findings. In our research we have applied digital subtraction angiography (DSA) to such patients. One of the advantages' of DSA is that angiography can be performed after intravenous administration of the contrast medium. Although spatial resolution with this method is inferior, the contrast resolution is excellent and DSA can be performed simply and noninvasively (CHRISTENSEN et al., 1980; HESSELINK et al., 1984). Doppler sonography has been used to determine whether Received for publication August 14, 1986 S 113
T. INAMORI et af.
S 114
a vertebral artery is open or occlusive, but this technique is less reliable for vertebral stenosis and gives no information about the basilar artery. We were able to find a considerable number of abnormalities in many cases. SUBJECTS AND METHODS
Thirty patients with intractable positional vertigo spells -except benign paroxysmal positional vertigo-, resistant to treatment, with some signs of CNS disturbance, but no significant findings with the CT scan, and who had requested further study were referred for DSA testing. DSA was performed using a Shimazu 100 digital angiographic system. With this system the X-ray passing through the body is amplified and converted in an image intensifier to an electric signal and recorded with a TV camera. After logarithmic amplification, the signal is converted to digital information by the AID converter, and sent to a processor which incorporates a microcomputer. The A/D conversion is performed on a matrix of 512 x 512 and has gray scales which are 9 bits deep. In the processor, 2---4 frames of mask images are added and the information is stored in one of the digital frame memories. After the addition of contrast medium and, after subtraction from the mask images, these signals are transmitted to another digital frame memory. Information from the two frame memories then passes through the digital/analog converter and image processing units, and is displayed on TV monitors as final processed images. After processing, the images are recorded on a video disk recorder, a video tape recorder, and the X-ray
I X·ray
Tube L:J
I
c:Lr:J
Shutter
Fig. 1.
~
Block diagram of DSA.
IV DSA AND POSITIONAL NYSTAGMUS
S 115
films (Fig. I). A 5 French Katzen Digiflex (Meditec®) catheter was introduced into an antecubital vein and positioned in the superior vena cava with fluoroscopic monitoring. Then 25-40 ml of Urografin-76 was injected at a rate of 15-20 ml/sec. Routine anteroposterior views were taken with and without the patient's head turned 45° to the right and left 45° to the left of the cervical vertebral arteries and AP and lateral views were taken of the basilar artery. The DSA imaging was performed on 30 patients-12 males and 18 females (averaging 52.7 years in age). The images of the vertebral and basilar arteries were evaluated for each patient. Representative figure of actual DSA is shown in Fig. 2. The location of the vessel stenosis, its grade and bending or kinking were analyzed. Then the DSA results were compared with the patient's equilibrium examination. In order to clarify the location of the vessels' stenosis, the vertebral artery area was divided into three parts. The first part (1) was designated as the region extending from its source to the level of bifurcation of the carotid artery. The second part (2) was from the level of bifurcation of the carotid artery to the magnum. The third aprt (3) was the intracranial vertebral artery. And the grade of stenosis was categorized as complete obstruction (a), severe stenosis (b), and mild stenosis (c). For some cases the measurement of the rate of blood
Fig. 2.
Representative figure of actual DSA.
S'116
T. INAMORI et
at.
flow was also calculated from the digital information obtained from DSA. Then the existence and cause of meandering, bending, and kinking were investigated. RESULTS
DSA studies resulted in 3 cases with normal findings (10%) and 27 cases with abnormal findings (90%). If the results of IV DSA are considered separately there are more than 27 abnormalities, since there are more than two positions in one patient (Table 1).
A.
Location of stenosis In 7 cases stenosis was on the right, in 10 on the left, and in 10 on both sides. Stenosis from the source of the vertebral artery to the level of bifurcation of the carotid artery was found in 14 cases. In 13 cases the entire vertebral artery was involved. Extracranial vertebral arteries with stenosis were found in 3 cases, and intracranial vertebral arteries with stenosis in 3. From the level of bifurcation of the carotid artery to the intracranial vertebral artery there was only 1 case. Table 1. Summary of DSA results of all 30 patients. Normal Abnormal
(cases)
(%)
3 27
10.0 90.0
10
33.3
7 10
23.3 33.3
Side Bilateral Unilateral Right Left Location Entire vertebral region Part of vertebral region Inf. half of extracranial Extracranial Intracranial Sup. half of extracranial and intracranial
13
43.3
14 3 3 1
46.7 10.0 10.0 3.3
Grade Complete obstruction Severe stenosis Mild stenosis
4 23
13.3
Bending No meandering, bending, nor kinking Meandering, bending, and kinking due to osteophytes Meandering, bending, and kinking due to Power's syn.
10
33.3
11 6
36.7 20.2
Meandering, bending, and kinking due to atherosclerosis
14
46.2
3.3 73.3
IV DSA AND POSITIONAL NYSTAGMUS
S 117
B.
Grade of stenosis One side of complete obstruction was found in one case, the severe grade of stenosis in 4 and the mild grade in 23. Using the method described in Fig. 3, blood flows of the vertebral artery in 10 cases were measured. In 7 out of 10 cases the rate on the one side was more than twice the rate on the another side, and in case 7 the rate measured in the right vertebral artery decreased from 67.5 mljmin to 42.5 mljmin, as the patient turned his neck to the left. Also, a severe grade of stenosis was found in the left vertebral artery of a 54-year-old female patient with a normal rate of
Density
:--lIt--: : I
I
A
B
Time
Fig. 3. Schematic illustration of blood flow measurement. Set the measuring points of ROI (region of interest) to 1 and 2, then draw two time-density curves with their differential curves. The microcomputer finds the turning points of A and B from two differential curves, and also measures the distance between 1 and 2, and the diameter of blood vessel in 1 and 2 at the time of A and B. Thus, the amount of blood flow can be estimated by dividing the value of volume between 1 and 2 by LIt. 1', differential curve of 1; 2", differential curve of 2. Table 2. The data ot blood flow rate in vertebral artery (VBF) measure in 10 cases. No.
Case
Age
Sex
1 2 3 4 5 6 7
A.M. A.U. K.M. Y.!. E.K. H.H. C.H.
59 52 72 61 66 57 59
M M M F M M F
8 9 10
S.N. M.N. A.I.
37 50 50
F M M
* Lt rotation.
VBF (ml/min) R
L
52.5 46.3 35.2 108 21. 2 101 67.5 42.5 196 126 263
169 51. 9 10.2 80.1 215 44.5 49.8 68.4* *70 136 51. 8
S 118
T. INAMORI et al.
129.0 ml/min in the right position and a rate of 5.13 ml/min in the left position (Table 2).
Existence of meandering, bending, and kinking For 17 cases in which meandering, bending, or kinking was found, I I were diagnosed as osteophytes on cervical vertebrae, and 6 cases as Power's syndrome (POWERS et al., 1961) or abnormal irritation of the cervical sympathetic nerve. C.
D.
DSA results and equilibrium examination With equilibrium examination gaze, nystagmus was found in 12 cases and spontaneous nystagmus in 15 cases. In 6 cases, gaze nystagmus was in one direction (right or left), in 2 it was in two directions (rgiht and left) and in one case it was in three directions (right, left, and up). In 7, spontaneous nystagmus was in one direction and in 8 it was in two directions. Since positional vertigo was the main complaint of the patients in this study, positional nystagmus naturally occurred in all 20. Positional nystagmus test was performed on the bed in supine position. Nine cases had nystagmus which was changing but always in a downward direction; that is, nystagmus elicited to the same direction as the recumbent or neck torsion side. Three cases had nystagmus changing in an upward direction (direction changing upward nystagmus), that is, nystagmus elicited to the opposite direction to recumbent or neck torsion side. Twelve cases had only one directional downward nystagmus. One case had direction fixed horizontal nystagmus, and one had direction fixed vertical nystagmus. Three had horizontal nystagmus in their body sagittal plane. DISCUSSION
Vertigo that is dependent on the position of the patient's head is called positional vertigo. Nystagmus produced by torsion of the neck may be tested for by either turning the neck on the body or by holding the head stationary and turning the body from side to side. About 80-90% of positional nystagmus is the benign positional type. The benign paroxysmal positional vertigo condition is produced when the patient's head is placed in a certain position. This vertigo can be provoked by the DIX-HALLPIKE (1952) provocation test when the affected ear is down. It has a short latency period and is shortly adaptable and easily fatigable. Also its nystagmus is chiefly rotatory in nature and it usually stops in 10-15 sec, and lasts a shorter time with each test until it cannot be produced by position changes. SCHUKNECHT and RUBY (1973) postulated that this vertigo which they termed "cupulo-lithiasis," is due to the adherence of degenerated otoliths to the cupula of the posterior semicircular canal, which changes the specific gravity of the cupula and causes gravity to affect the cupula.
IV DSA AND POSITIONAL NYSTAGMUS
S 119
The disease may persist for weeks or months and then disappear forever, or may recur spontaneously many months or years later. Occasionally it is persistent and continues unchanged for years. It is important to investigate the character of positional nystagmus when a patient complains of vertigo for a long time in spite of treatment. Because of vertebral stenosis, infarction or tumors of the brain stem, cerebellar disease, or various neck disorders, another type-malignant positional nystagmus-may occur. The malignant positional nystagmus, in contrast to the benign type, has no period of latency, is nonfatigable and lacks rotatory component, usually in the horizontal plane but occasionally in the oblique or vertical plane. The nystagmus may change directions during the test position. In a discussion of vertebro-basilar insufficiency, the two major arteries involved are the anterior inferior cerebellar artery, which is a branch of the basilar artere, and the posterior inferior cerebellar artery, which is a branch of the vertebral artery. Atherosclerosis is probably the most common cause of vascular insufficiency. Extrinsic pressure on the arteries that supply the inner ear and brainstem can cause vertebro-basilar insufficiency. These problems occur most often in the neck, where the vertebral vessels pass through the transverse foramina. Osteophytic spurs due to arthritis, a cervical rib, fibrous and muscular bands or congenital anomalies of the cervical vertebrae may compress the vertebral arteries. Three basic mechanisms have been proposed to explain the occurrence of cervical vertigo. These are disturbed vertebro-basilar insufficiency (HUTCHINSON, 1956), involvement of the sympathetic vertebral plexus (WELDHAGEN, 1958), and involvement of the sensory afferent fibers in the neck muscle (COPE and RYAN, 1959). Treatment shouldn't be instituted until the diagnosis and associated disorders are clearly established. An otoneurologic consultation and special studies, including IV DSA are necessary. Intravenous DSA has some advantages over selective vertebral arteriography. There is minimal risk of stroke, and the study can be done on an outpatient basis with immediate calculation of the rate of blood flow in any vessels. Since DSA studies are conducted in real time on the monitor screen, we can observe the change in blood flow rate due to vessel compression by torsion of the patient's neck, and his positional nystagmus. In this study the DSA results were compared to the patient's equilibrium examination, but disappointingly no correlation could be found. It is difficult to determine the side or location of stenosis from the nystagmus findings. The DSA examination must be conducted immediately to determine the cause of nystagmus, but considering abnormalities fO:.Jnd in DSA as the direct cause of vertigo is insufficient. Various forms of examination must be used to determine the cause. However, we have two cases who had been diagnosed as Power's syndrome, and patients were treated successfully by performing a
S 120
T. INAMORI et
at.
stellate gangling block. For this reason, in these 2 cases abnormal stimulation of the cervical sympathetic nerve causes stenosis of the vertebral artery which leads to insufficiency when the direction of the head is changed, and vertigo was experienced by them when there was stenosis of a blood vessel. It should be emphasized from our present study that the direction of positional nystagmus is not always correlative with the stenotic region of the vertebrobasilar system and performing DSA is a method of choice to reveal the stenotic lesion. CONCLUSION
Intravenous DSA studies were performed in 30 cases with intractable positional nystagmus. Abnormalities were found in 27 cases. The following results were obtained from this study of positional nystagmus and DSA. 1. Partial stenosis of the vertebral region occurred in 14 cases. Stenosis of the entire vertebral region occurred in 13 cases. Many of the former showed changes in direction of downward nystagmus and many of the latter were one directional in downward nystagmus. 2. Complete obstruction of the vertebral artery was found in 1 case, severe stenosis in 4 cases and mild stenosis in 23 cases. 3. Meandering, bending, and kinking of the vertebral artery occurred in 17 cases. In many of these cases nystagmus was downward in one direction. 4. Meandering, bending, and kinking of the vertebral artery due to osteophytes occurred in 11 cases. Three of these cases showed directional changing nystagmus and 3 of these cases showed one directional down beat nystagmus. Power's syndrome was present in 6 cases and atherosclerosis in 14 cases. 5. The blood flow of the bilateral vertebral artery was measured. DSA studies are important and useful in determining the cause of positional nystagmus. REFERENCES CHRISTENSEN, P.C., ORITT, T.W., FISHER, H.D., FROST, M.M., NUDELMAN, S., and ROEHRIG, H.: Intravenous angiography using digital video subtraction. AJR 135: 1145-1152, 1980. COPE, S., and RYAN, G.M.S.: Cervical and otolith vertigo. J. Laryngol.73: 113-120, 1959. DIX, M.R., and HALLPIKE, C.S.: The pathology symptomatology & diagnosis of certain common disorders of the vestibular system. Proc. R. Soc. Med. 45: 15-28, 1952. HESSELINK, 1.R., TERESI, L.M., DAVIS, K.R., and TAVERAS, 1.M.: Intravenous digital subtraction angiography of arteriosclerotic vertebrobasilar disease. AJR 142: 255-260, 1984. HUTCHINSON, E.C., and YATES, P.O.: The cervical portion of the vertebral artery: A clinicopathological study. Brain 79: 319-331, 1956. NAGASHIMA, C.: Surgical treatment of vertebral artery insufficiency caused by cervical spondylosis. J. Neurosurg. 32: 512-520, 1970.
IV DSA AND POSITIONAL NYSTAGMUS
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POWERS, S.R., DRISLANE, T.H., and NEVINS, S.: Intermittent vertebral artery compression : A new syndrome. Surgery 49 : 257-264, 1961. SCHUKNECHT, H.F.: Cupulolithiasis. Arch. Otolaryngol. 90: 113-126, 1969. SCHUKNECHT, H.F., and RUBY, R.R.: Cupulolithiasis. Adv. Otorhinolaryngol. 20: 434-443, 1973. WELDHAGEN, F.: Ein KIinischer Beitrag zur Pathogenese Hydropischer Innenohyprozette. Acta Otolaryngol. 49: 256-268, 1958.
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Request reprints to : Dr. T. Inamori. Department of Otolaryngology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663, Japan