- Email: [email protected]
BPPV and Variants: Improved Treatment Results with Automated, Nystagmus-Based Repositioning
Otolaryngology–Head and Neck Surgery (2005) 133, 107-112
BPPV and Variants: Improved Treatment Results with Automated, Nystagmus-Based Repositioning Meiho Nakayama, MD, PhD,a John M. Epley, MDb a
From the Department of Otolaryngology, Aichi Medical University, Aichi Prefecture, Japan and Portland Otologic Clinic, Portland.
b
OBJECTIVE: Although classical benign paroxysmal positional vertigo has generally been resolvable by routine manual repositioning maneuvers, nevertheless resistant cases and variants remain a significant problem. We investigated the efficacy of analyzing and treating positional vertigo with a system that provides unlimited, automated maneuverability of the patient while maintaining constant electronic monitoring of nystagmus. STUDY DESIGN AND SETTING: A power-driven, multiaxial positioning chair combined with ongoing infrared videooculography was used to manage 986 subjects in a tertiary clinical setting with complaints of positional vertigo. A nystagmus-based strategy and condition-specific protocols were used. RESULTS: Significantly enhanced treatment outcomes were achieved, especially regarding intransigent and variant forms. Pertinent correlations were noted. CONCLUSION: This multi-axial positioning chair combination provided enhanced diagnostic and treatment capabilities for managing positional vertigo, apparently due to improved analytical capability, precision repeatability, and unlimited 360-degree maneuverability. SIGNIFICANCE: This advancement should be considered for tertiary management of complicated labyrinthine lithiasis. © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
R
epositioning maneuvers (RMs), when carried out manually to treat positional vertigo caused by typical benign paroxysm positional vertigo (BPPV), or canalithiasis of the posterior semicircular canal, have been widely reported to have a success rate ranging up to 80% to 90%.1-6
This was offered as a poster presentation at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery on September 21-24, 2003, Orlando, Florida. Reprint requests: Meiho Nakayama, MD, PhD, Department of Otolar-
This is generally regarded as a highly acceptable success rate and would seem to infer that there is little need to seek improvement. However, an 80% to 90% success rate indicates a 10% to 20% failure rate, and, when one takes into account that BPPV is documented to be one of the most common causes of vertigo,7-10 this failure rate encompasses a rather significant number of patients overall. Furthermore, these intransigent cases tend to be the most severe and disabling, with greater risk of falls. When seen in this light, there are substantial grounds for seeking improved methods and using more advanced technology. In addition, there has been an increasing awareness and interest in using RMs for treating atypical forms of labyrinthine lithiasis, the so-called “BPPV variants.”11,12 These variants include canalithiasis of the horizontal or anterior semicircular canals (SCs), as well as cupulolithiasis or canalith jam in any of the SCs. The success rate with manual RMs applied to these atypical forms varies with the particular form, but is well below the success rate with the typical form, and in some cases is somewhat less than 25%.11,12 Considerably more complex and technically difficult to both analyze and treat, these more formidable forms of labyrinthine lithiasis have further served to emphasize the need for better methods. A wealth of information regarding the pathophysiology present in positional vertigo patients can be gleaned from nystagmus observation, especially via infrared video, throughout diagnostic and treatment maneuvers. In canalithiasis, believed to be caused by loose particles in a semiyngology, Aichi Medical University, Aichigun, Aichiken, 480-1195, Japan. E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.03.027
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circular canal (SC) that shift to produce currents in the endolymph with a change in spatial orientation of the head, the nystagmus pattern demonstrates a period of latency from the time that a provocative position is assumed, followed by sudden onset of transient nystagmus. Cupulolithiasis, on the other hand, caused by particles that impinge upon, or are attached to, a cupula, produces a completely different pattern of nystagmus. The weighted cupula is abnormally affected by gravity in certain head positions, producing nystagmus of gradual onset as the inertia of the endolymph around the semicircular loop is overcome, and persistence as long as the provocative position is held. A canalith jam, probably in most cases associated with particles lodged against a cupula, is identified by a sudden onset of persistent nystagmus unaffected by position. The SC of involvement in labyrinthine lithiasis can be identified by the nystagmus profile, with the plane of the nystagmus following the plane of the originating SC. Complementary pairs of SCs in the same plane can be delineated by noting the position that provokes the nystagmus. The nystagmus patterns and profiles may change during treatment maneuvers, indicating a change in pathophysiology, a need for appropriate adjustment in RM strategy, and emphasizing the requirement for continuous observation. Canalithiasis of either the posterior or anterior SCs is usually resolved by the canalith repositioning procedure.1 Horizontal canalithiasis tends to produce more severe symptoms, is typified by extreme but transient horizontal nystagmus, and is treatable with roll-over RMs. Cupulolithiasis symptoms are usually less severe than canalithiasis, though they frequently have a more constant presentation. Treatment of cupulolithiasis at the Portland Otologic Clinic (POC) is designed to invert the involved cupula and apply oscillation if necessary so that the particles can escape the cupular surface. Treatment of canalith jam at the POC is designed to back the particles away from the jam with gravity and applied oscillation, and then reposition the loosened particles as usual. Manual RMs have inherent physical limitations that prevent placing the patient in certain positions or moving them through certain planes, such that the ideal therapeutic positions and planes relative to the semicircular canals and cupulae can only be approximated in most cases. In addition, direct observation of the eyes during manual maneuvers is generally inadequate for monitoring of ongoing eye movements in order to effectively carry out a nystagmusbased strategy. The introduction of infrared video goggles has provided a significant advancement for monitoring nystagmus, but if used during manual maneuvers they tend to be easily displaceable relative to the head, presenting problems with stabilization of the ocular image. In consideration of these factors, we investigated the efficacy of analyzing and treating symptoms of positional vertigo with a system that provided unlimited, as well as automated, maneuverability of the patient while maintaining constant video monitoring of nystagmus.
Figure 1 This study used a power-driven, multi-axial chair/ infrared video (MAC/IRV) combination (Omniax System).
METHOD This study used a power-driven, multi-axial chair/infrared video (MAC/IRV) combination (Omniax System) that was developed at the Portland Otologic Clinic (Portland, Oregon) in 1996 (Fig 1). Providing 2 axes with full 360-degree rotation, and a third axis for adjusting the pitch plane, the chair can be positioned at any angle relative to gravity (including inversion) and can rotate the subject in any plane, while providing constant monitoring of eye movement. For treatment of canalithiasis, full 360-degree rotation of any one of the SCs in the true earth-vertical plane can be accomplished with accuracy and ease. For treatment of cupulolithiasis, accurate and inverted orientations of the head are easily accomplished as well. Subjects are fitted with eye goggles incorporating a small infrared video camera. The goggles are better stabilized by the fact that the head is kept stationary with respect to the body. These factors provide unfettered monitoring of eye movement throughout the maneuvers, thus allowing maneuver sequences to be appropriately timed or altered according to the presenting nystagmus at any given time. The video display of the eye, with an inset showing the simultaneous orientation of the chair, is combined with audio recording to provide full documentation. The detailed methodology for analyzing the nystagmus generated by various forms of labyrinthine lithiasis, and treating each by RMs under a nystagmus-based strategy, is available in published material.11 Briefly summarized, the character and localization of pathophysiology, which may change from moment to moment during test and treatment maneuvers, are deduced by continually correlating the pattern and plane/axis of the induced nystagmus with the ongoing position/positioning of the head. Accordingly, treatment is carried out with the selection and timing of the maneuvers based on the simultaneous observation of the constantly evolving eye movement findings. This nystagmus-based strategy is the fundamental element on which all
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BPPV and Variants: Improved Treatment Results . . .
109
Table 1 Number of treatment sessions required for each pathological entity Pathology Canalithiasis Cupulolithiasis Canalith jam Unknown All cases
Total cases
Group A: 1 session
Group B: 2-3 sessions
705 93 32 3 833
675 (95.7%) 33 (35.4%) 13 (40.6%) — 721 (86.6%)
30 (4.3%) 53 (57.0%) 15 (47.0%) — 98 (11.8%)
Group C: No improvement
7 4 3 14
— (7.5%) (12.5%) (100%) (1.7%)
maneuvers are carried out on the MAC/IRV system at the POC. Patients were given postprocedure instructions pertinent to the condition that was under treatment, which was generally to avoid positions that would lead to recurrence of that condition, and patients were typically advised to return as necessary until diagnostic maneuvers indicated a persistent resolution of the nystagmus, and vertigo symptoms were no longer present.
Evaluation of Treatment
STUDY DESIGN
Special, Condition-specific Maneuvers
The charts of 986 patients who were managed at the POC from January 1996 to September 2002 on the MAC/IRV system for complaints of positional vertigo were reviewed. Of these, 612 (62%) were women and 374 (38%) were men, with an average age of 59.7 ⫾ 12.5 (Mean ⫾ SD), from 22 to 83 years old. Of 986 subjects evaluated, 152 (15.6%) had failed to demonstrate significant, abnormal, positional or positioning nystagmus, despite several attempts to elicit it with Dix-Hallpike maneuvers, oscillation application, and placement in other provocative positions. These patients were excluded from the study in view of the fact that positional vertigo symptoms can be caused by a variety of other pathology, including perilymph fistula, postural hypotension, chronic labyrinthine dysfunction, anterior canal dehiscence, etc. Also excluded were patients who did not return for a confirmatory visit as requested after a single treatment session. Most of these were contacted by telephone and indicated a lack of incentive to return because their positional vertigo symptoms were completely resolved.
The remaining 833 patients had been treated immediately after diagnosis via the MAC/IRV system. An extensive review of each patient’s chart and videography tape was undertaken. The apparent pathophysiology, location of particles, and response to treatment were analyzed for each. “Significant improvement” was defined as clearance of all significant position-induced nystagmus at the end of a session, as well as verification at a follow-up session of a sustained absence of both position-induced nystagmus and positional vertigo symptoms.
Patients who had not demonstrated timely improvement in their induced nystagmus with standard CRP treatment on the MAC/IRV system had undergone condition-specific maneuvers as follows: for horizontal canalithiasis, a 360-degree roll in the plane of the horizontal SC in the direction contralateral to the side of involvement; for horizontal cupulolithiasis, inversion of the head 180 degrees relative to the position of maximum elicitation; for anterior canalithiasis, an anterior 360-degree flip with 45-degree offset contralateral to the target ear. To minimize early recurrence, and when easily tolerated by the patient, the standard CRP was followed by a backward 360-degree flip with 45-degree ipsilateral offset, with oscillation.
RESULTS The results are summarized in Tables 1, 2 and 3 with respect to response to treatment in the 833 patients who had confirmed positional nystagmus. After 1 treatment session,
Table 2 Number of treatment sessions required for each semicircular canal involved Pathology Anterior SC Horizontal SC Posterior SC Multiple
Total cases 19 84 553 177
Group A: 1 session 12 75 549 85
(63.2%) (89.2%) (99.3%) (48.0%)
Group B: 2-3 sessions 7 9 4 78
(36.8%) (10.7%) (0.7%) (44.1%)
Group C: No improvement — — — 14 (7.9%)
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Table 3 Procedures used during repositioning treatment in 833 patients Procedure Canalith repositioning Backward 360° while 45° to ipsi side BBQ 360° roll: ipsi for cup., contra for can. Forward 360° while 45° to contra side Oscillation proved essential
Number of cases (%) 814 615 137 67 293
(97.7) (73.8) (16.4) (4.3) (35.2)
Principle applications Can of anterior or posterior SC Clearing apex with can of posterior SC Can, cup, jam of horizontal SC Cup, jam of anterior SC When procedure was not effective until oscillation applied; all cup and jam
SC, Semicircular canal; can, canalithiasis; cup, cupulolithiasis; ipsi, ipsilateral; contra, contralateral.
86.6% (group A) demonstrated significant improvement (Table 1). With 1 or 2 additional treatments, another 11.8% (group B) demonstrated significant improvement. Approximately 2% of patients did not respond to any treatment after undergoing 4 or more sessions (group C).
Primary Pathophysiology Analysis indicated the primary pathophysiology (Table 1) to be canalithiasis in 84.6%, cupulolithiasis in 11.2%, and canalith jam in 3.8%. In comparing the response to treatment, only 4.3% of cases with canalithiasis required more than 1 session to obtain significant improvement, whereas 57.0% of cases with cupulolithiasis required 2 or 3 sessions, and 7.5% were not improved after 4 or more sessions.
Semicircular Canal of Involvement Based on the nystagmus pattern and the simultaneous position/positioning of the patient, the SC location of the abnormal particles was assessed (Table 2). The posterior SC was involved in 66.4% of cases, horizontal SC in 10.1%, anterior SC in 2.3%, and multiple SCs in 21.3%. These results are generally in agreement with others.13,14 In comparing the effectiveness of treatment in the 3 SCs, regardless of the form of lithiasis, only 1 treatment session (with a follow-up validation session) was required for involvement of either a posterior SC (99.3% of cases) or for a horizontal SC (89.2%). However, 2 or 3 sessions were required with involvement of the anterior SC in 36.8%, or multiple SCs in 44.1%. In addition, multiple SCs were involved in all patients who failed to show lasting improvement.
No Surgery Required During the period of this study, none of the 833 subjects were treated with surgery, although this option was offered for a few cases that were subject to frequent recurrences or demonstrated no improvement. Previously, while treating these conditions at the POC with manual maneuvers, approximately 5% were being treated with surgery (singular neurectomy or canal plugging).
DISCUSSION This study indicates that, given optimal methodology and equipment for undertaking RMs, better results can be achieved than were previously realized. Unfortunately, the resolution rates for the specific variants when treated with manual maneuvers have not been addressed in the literature, and therefore a direct comparison is not feasible. Nevertheless, the aforementioned estimate of less than 25% resolution for all uncategorized variants was clearly eclipsed in the present study. In fact, many patients had failed treatment with manual maneuvers attempted elsewhere and had been referred to the POC for evaluation and treatment with this special modality. Another significant factor was the lack of surgery (none in 833 cases) required for these conditions. Although several surgical procedures14-16 are in use for treatment of labyrinthine lithiasis that is refractory to conservative treatment, the results in this study suggest surgery should rarely be indicated.
Improved Nystagmus Observation In our experience, prior to the use of the MAC/IRV combination, when attempting to use IR video goggles during manual maneuvers, it was frequently difficult to maintain a stabilized image of the eye. However, when using IR video goggles with the positioning chair, this problem was minimized as the whole body was moved rather than just the head, and therefore an unfettered view of the eye position could be maintained throughout. The value of this improved nystagmus observation throughout RMs cannot be overemphasized, because most abnormal nystagmus induced by position or positioning is secondary to displaced otoliths or other dense material that directly or indirectly affects SC physiology.1,11,17 Thus, nystagmus observation provides information crucial to determine the ongoing status of a dynamic pathophysiologic process. This ongoing nystagmus observation can determine, for instance, when conversion to another canal has taken place, the approximate location of the particles within the canal(s), best treatment pathways, and whether all the particles have cleared the canal. Without this information, the operator
Nakayama and Epley
BPPV and Variants: Improved Treatment Results . . .
is taking a less-than-scientific guess as to the ongoing pathophysiological status relative to the canal(s) of involvement.
Unlimited Maneuverability The unlimited maneuverability provided by the positioning apparatus made possible the special, condition specific maneuvers that were necessary in many cases to obtain resolution. For instance, the value of a controlled, 360-degree rotation in any plane was illustrated in diagnosing and treating cases in which, by our analysis, the repositioning of particles was blocked at the posterior SC apex. The typical case had failed attempts at CRP elsewhere and then failed to respond initially at the POC to routine CRP measures. Analysis on the MAC/IRV system localized the problem through accomplishing a backward “360” while keeping the target SC coplanar with gravity. This maneuver induced a torsional nystagmus that would suddenly cease at a point where the patient’s head was generally between 120 to 180 degrees back from upright; then, on continuing to rotate the SC through 270 degrees, there would be a reversal of the torsional nystagmus with retention of the same axis of rotation. This reversal is interpreted as an indication that particles had failed to pass the apex and were gravitating back toward their original location. This apex blockage problem was usually resolved by providing a similar backward 360-degree flip while the head was turned 45 degrees to the ipsilateral side, but more slowly and with oscillation applied. This was timed to keep the particles moving toward the utricle throughout the rotation, as indicated by continuing nystagmus in the same direction. If necessary, the SC was rotated so that the obstructed segment of the posterior PSC was oriented vertically, whereupon broad angular back-andforth movements of the chair were used to impart longitudinal forces, in addition to the gravitational forces, to the particles. The value of this 360-degree capability is also illustrated in the various frontward flips, backward flips, and rolls discussed above.
Ease and Safety of Use Another advantage of the MAC/IRV combination is the ease with which the operator can move the patient through multiple complex maneuvers without this task interfering significantly with the operator’s simultaneous task of monitoring the nystagmus and formulating a response thereto. This ease of use is also illustrated by some complicated cases in which numerous maneuvers were necessary within a single session to accomplish effective treatment. These have sometimes run to over 40 sequential changes of position, with testing, treating, and retesting numerous times. If attempted manually, such
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extensive maneuvering would be exhausting for both the patient and operator. The other significant factor with manual maneuvers is the risk to medical personnel in lifting and turning patients, particularly patients who are overweight or debilitated. With a positioning chair, this risk is significantly minimized.
CONCLUSION In the our opinion, after carrying out RMs by manual means over a period of years, we find that the MAC/IRV combination provided definite advantages in terms of convenience, maneuverability, 360-degree capability, precise orientation, improved safety, all-inclusive nystagmus observation, and electronic documentation. The value of this type of hardware to the diagnosis and treatment of BPPV and variants, especially complicated cases, has been well demonstrated by this study. This combination has produced improved diagnostic and treatment results, as well as several insightful observations that can be applied to RMs carried out by any means. The fact that a significant proportion of cases in this study had been referred for evaluation and treatment by this modality after manual RM failure speaks well for the efficacy of this modality. Arrangements are underway to make this equipment, with appropriate software, available on the market. Estimates place its cost somewhat above the level of a rotational chair with associated software, but it appears to have far greater potential clinical value. Pending an indepth cost-benefit analysis, the feasibility of equipment with similar capability for general deployment at tertiary centers for management of vestibular conditions remains unproven, but the POC experience has been very positive.
REFERENCES 1. Epley JM. The canalith repositioning procedure: for treatment of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 1992;107:399 – 404. 2. Herdman SJ, Tusa RJ, Zee DS, et al. Single treatment approaches to benign paroxysmal positional vertigo. Arch Otolaryngol Head Neck Surg 1993;119:450 – 4. 3. Smouha EE. Time course of recovery after Epley maneuvers for benign paroxysmal positional vertigo. Laryngoscope 1997;107:187– 91. 4. Welling DB, Barnes DE. Particle repositioning maneuver for benign paroxysmal positional vertigo. Laryngoscope 1994;104:946 –9. 5. Mujeeb M, Khan N. Epley’s manoeuvre: treatment of choice for benign paroxysmal positional vertigo. J Laryngol Otol 2000;114:844 –7. 6. Wolf M, Hertanu T, Novikov L, et al. Epley’s manoeuvre for benign paroxysmal positional vertigo: a prospective study. Clin Otolaryngol 1999;24:43– 6.
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7. Froehling DA, Silverstein MD, Mohr DN, et al. Benign positional vertigo: incidence and prognosis in a population-based study in Olmsted county. Mayo Clin Proc 1991;66:596 – 601. 8. Nedzelski J, Barber H, McIlmoyyl L. Diagnosis in a dizziness unit. J Otolaryngol 1986;15:101– 4. 9. Mizukoshi K, Watanabe Y, Shojaku H, et al. Epidemiological studies on benign paroxysmal positional vertigo in Japan. Acta Otolaryngol (Stockh) 1988;suppl 447:67–72. 10. Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope 1997;107:607–13. 11. Epley JM: Human experience with canalith repositioning maneuvers. Ann N Y Acad Sci 2001;942:179 –91. 12. Honrubia V, Baloh RW, Harris MR, et al. Paroxysmal positional vertigo syndrome. Am J Otol 1999;20:465–70.
13. Macias JD, Lambert KM, Massingale S, et al. Variables affecting treatment in benign paroxysmal positional vertigo. Laryngoscope 2000;110:1921– 4. 14. Gacek RR, Gacek MR. Update on the pathology and management of benign paroxysmal positional bertigo. Otorhinolaryngol Nova 1998;8: 235– 44. 15. Parnes LS. Update on posterior canal occlusion for benign paroxysmal positional vertigo. Otolaryngol Clin North Am 1996;29:333– 42. 16. Anthony RF. Partitioning the labyrinth for benign paroxysmal positional vertigo: clinical and histologic findings. Am J Otol 1993;14: 334 – 42. 17. Epley JM. New dimensions of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 1980;88:599 – 605.
BPPV and Variants: Improved Treatment Results with Automated, Nystagmus-Based Repositioning Meiho Nakayama, MD, PhD,a John M. Epley, MDb a
From the Department of Otolaryngology, Aichi Medical University, Aichi Prefecture, Japan and Portland Otologic Clinic, Portland.
b
OBJECTIVE: Although classical benign paroxysmal positional vertigo has generally been resolvable by routine manual repositioning maneuvers, nevertheless resistant cases and variants remain a significant problem. We investigated the efficacy of analyzing and treating positional vertigo with a system that provides unlimited, automated maneuverability of the patient while maintaining constant electronic monitoring of nystagmus. STUDY DESIGN AND SETTING: A power-driven, multiaxial positioning chair combined with ongoing infrared videooculography was used to manage 986 subjects in a tertiary clinical setting with complaints of positional vertigo. A nystagmus-based strategy and condition-specific protocols were used. RESULTS: Significantly enhanced treatment outcomes were achieved, especially regarding intransigent and variant forms. Pertinent correlations were noted. CONCLUSION: This multi-axial positioning chair combination provided enhanced diagnostic and treatment capabilities for managing positional vertigo, apparently due to improved analytical capability, precision repeatability, and unlimited 360-degree maneuverability. SIGNIFICANCE: This advancement should be considered for tertiary management of complicated labyrinthine lithiasis. © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
R
epositioning maneuvers (RMs), when carried out manually to treat positional vertigo caused by typical benign paroxysm positional vertigo (BPPV), or canalithiasis of the posterior semicircular canal, have been widely reported to have a success rate ranging up to 80% to 90%.1-6
This was offered as a poster presentation at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery on September 21-24, 2003, Orlando, Florida. Reprint requests: Meiho Nakayama, MD, PhD, Department of Otolar-
This is generally regarded as a highly acceptable success rate and would seem to infer that there is little need to seek improvement. However, an 80% to 90% success rate indicates a 10% to 20% failure rate, and, when one takes into account that BPPV is documented to be one of the most common causes of vertigo,7-10 this failure rate encompasses a rather significant number of patients overall. Furthermore, these intransigent cases tend to be the most severe and disabling, with greater risk of falls. When seen in this light, there are substantial grounds for seeking improved methods and using more advanced technology. In addition, there has been an increasing awareness and interest in using RMs for treating atypical forms of labyrinthine lithiasis, the so-called “BPPV variants.”11,12 These variants include canalithiasis of the horizontal or anterior semicircular canals (SCs), as well as cupulolithiasis or canalith jam in any of the SCs. The success rate with manual RMs applied to these atypical forms varies with the particular form, but is well below the success rate with the typical form, and in some cases is somewhat less than 25%.11,12 Considerably more complex and technically difficult to both analyze and treat, these more formidable forms of labyrinthine lithiasis have further served to emphasize the need for better methods. A wealth of information regarding the pathophysiology present in positional vertigo patients can be gleaned from nystagmus observation, especially via infrared video, throughout diagnostic and treatment maneuvers. In canalithiasis, believed to be caused by loose particles in a semiyngology, Aichi Medical University, Aichigun, Aichiken, 480-1195, Japan. E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.03.027
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Otolaryngology–Head and Neck Surgery, Vol 133, No 1, July 2005
circular canal (SC) that shift to produce currents in the endolymph with a change in spatial orientation of the head, the nystagmus pattern demonstrates a period of latency from the time that a provocative position is assumed, followed by sudden onset of transient nystagmus. Cupulolithiasis, on the other hand, caused by particles that impinge upon, or are attached to, a cupula, produces a completely different pattern of nystagmus. The weighted cupula is abnormally affected by gravity in certain head positions, producing nystagmus of gradual onset as the inertia of the endolymph around the semicircular loop is overcome, and persistence as long as the provocative position is held. A canalith jam, probably in most cases associated with particles lodged against a cupula, is identified by a sudden onset of persistent nystagmus unaffected by position. The SC of involvement in labyrinthine lithiasis can be identified by the nystagmus profile, with the plane of the nystagmus following the plane of the originating SC. Complementary pairs of SCs in the same plane can be delineated by noting the position that provokes the nystagmus. The nystagmus patterns and profiles may change during treatment maneuvers, indicating a change in pathophysiology, a need for appropriate adjustment in RM strategy, and emphasizing the requirement for continuous observation. Canalithiasis of either the posterior or anterior SCs is usually resolved by the canalith repositioning procedure.1 Horizontal canalithiasis tends to produce more severe symptoms, is typified by extreme but transient horizontal nystagmus, and is treatable with roll-over RMs. Cupulolithiasis symptoms are usually less severe than canalithiasis, though they frequently have a more constant presentation. Treatment of cupulolithiasis at the Portland Otologic Clinic (POC) is designed to invert the involved cupula and apply oscillation if necessary so that the particles can escape the cupular surface. Treatment of canalith jam at the POC is designed to back the particles away from the jam with gravity and applied oscillation, and then reposition the loosened particles as usual. Manual RMs have inherent physical limitations that prevent placing the patient in certain positions or moving them through certain planes, such that the ideal therapeutic positions and planes relative to the semicircular canals and cupulae can only be approximated in most cases. In addition, direct observation of the eyes during manual maneuvers is generally inadequate for monitoring of ongoing eye movements in order to effectively carry out a nystagmusbased strategy. The introduction of infrared video goggles has provided a significant advancement for monitoring nystagmus, but if used during manual maneuvers they tend to be easily displaceable relative to the head, presenting problems with stabilization of the ocular image. In consideration of these factors, we investigated the efficacy of analyzing and treating symptoms of positional vertigo with a system that provided unlimited, as well as automated, maneuverability of the patient while maintaining constant video monitoring of nystagmus.
Figure 1 This study used a power-driven, multi-axial chair/ infrared video (MAC/IRV) combination (Omniax System).
METHOD This study used a power-driven, multi-axial chair/infrared video (MAC/IRV) combination (Omniax System) that was developed at the Portland Otologic Clinic (Portland, Oregon) in 1996 (Fig 1). Providing 2 axes with full 360-degree rotation, and a third axis for adjusting the pitch plane, the chair can be positioned at any angle relative to gravity (including inversion) and can rotate the subject in any plane, while providing constant monitoring of eye movement. For treatment of canalithiasis, full 360-degree rotation of any one of the SCs in the true earth-vertical plane can be accomplished with accuracy and ease. For treatment of cupulolithiasis, accurate and inverted orientations of the head are easily accomplished as well. Subjects are fitted with eye goggles incorporating a small infrared video camera. The goggles are better stabilized by the fact that the head is kept stationary with respect to the body. These factors provide unfettered monitoring of eye movement throughout the maneuvers, thus allowing maneuver sequences to be appropriately timed or altered according to the presenting nystagmus at any given time. The video display of the eye, with an inset showing the simultaneous orientation of the chair, is combined with audio recording to provide full documentation. The detailed methodology for analyzing the nystagmus generated by various forms of labyrinthine lithiasis, and treating each by RMs under a nystagmus-based strategy, is available in published material.11 Briefly summarized, the character and localization of pathophysiology, which may change from moment to moment during test and treatment maneuvers, are deduced by continually correlating the pattern and plane/axis of the induced nystagmus with the ongoing position/positioning of the head. Accordingly, treatment is carried out with the selection and timing of the maneuvers based on the simultaneous observation of the constantly evolving eye movement findings. This nystagmus-based strategy is the fundamental element on which all
Nakayama and Epley
BPPV and Variants: Improved Treatment Results . . .
109
Table 1 Number of treatment sessions required for each pathological entity Pathology Canalithiasis Cupulolithiasis Canalith jam Unknown All cases
Total cases
Group A: 1 session
Group B: 2-3 sessions
705 93 32 3 833
675 (95.7%) 33 (35.4%) 13 (40.6%) — 721 (86.6%)
30 (4.3%) 53 (57.0%) 15 (47.0%) — 98 (11.8%)
Group C: No improvement
7 4 3 14
— (7.5%) (12.5%) (100%) (1.7%)
maneuvers are carried out on the MAC/IRV system at the POC. Patients were given postprocedure instructions pertinent to the condition that was under treatment, which was generally to avoid positions that would lead to recurrence of that condition, and patients were typically advised to return as necessary until diagnostic maneuvers indicated a persistent resolution of the nystagmus, and vertigo symptoms were no longer present.
Evaluation of Treatment
STUDY DESIGN
Special, Condition-specific Maneuvers
The charts of 986 patients who were managed at the POC from January 1996 to September 2002 on the MAC/IRV system for complaints of positional vertigo were reviewed. Of these, 612 (62%) were women and 374 (38%) were men, with an average age of 59.7 ⫾ 12.5 (Mean ⫾ SD), from 22 to 83 years old. Of 986 subjects evaluated, 152 (15.6%) had failed to demonstrate significant, abnormal, positional or positioning nystagmus, despite several attempts to elicit it with Dix-Hallpike maneuvers, oscillation application, and placement in other provocative positions. These patients were excluded from the study in view of the fact that positional vertigo symptoms can be caused by a variety of other pathology, including perilymph fistula, postural hypotension, chronic labyrinthine dysfunction, anterior canal dehiscence, etc. Also excluded were patients who did not return for a confirmatory visit as requested after a single treatment session. Most of these were contacted by telephone and indicated a lack of incentive to return because their positional vertigo symptoms were completely resolved.
The remaining 833 patients had been treated immediately after diagnosis via the MAC/IRV system. An extensive review of each patient’s chart and videography tape was undertaken. The apparent pathophysiology, location of particles, and response to treatment were analyzed for each. “Significant improvement” was defined as clearance of all significant position-induced nystagmus at the end of a session, as well as verification at a follow-up session of a sustained absence of both position-induced nystagmus and positional vertigo symptoms.
Patients who had not demonstrated timely improvement in their induced nystagmus with standard CRP treatment on the MAC/IRV system had undergone condition-specific maneuvers as follows: for horizontal canalithiasis, a 360-degree roll in the plane of the horizontal SC in the direction contralateral to the side of involvement; for horizontal cupulolithiasis, inversion of the head 180 degrees relative to the position of maximum elicitation; for anterior canalithiasis, an anterior 360-degree flip with 45-degree offset contralateral to the target ear. To minimize early recurrence, and when easily tolerated by the patient, the standard CRP was followed by a backward 360-degree flip with 45-degree ipsilateral offset, with oscillation.
RESULTS The results are summarized in Tables 1, 2 and 3 with respect to response to treatment in the 833 patients who had confirmed positional nystagmus. After 1 treatment session,
Table 2 Number of treatment sessions required for each semicircular canal involved Pathology Anterior SC Horizontal SC Posterior SC Multiple
Total cases 19 84 553 177
Group A: 1 session 12 75 549 85
(63.2%) (89.2%) (99.3%) (48.0%)
Group B: 2-3 sessions 7 9 4 78
(36.8%) (10.7%) (0.7%) (44.1%)
Group C: No improvement — — — 14 (7.9%)
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Table 3 Procedures used during repositioning treatment in 833 patients Procedure Canalith repositioning Backward 360° while 45° to ipsi side BBQ 360° roll: ipsi for cup., contra for can. Forward 360° while 45° to contra side Oscillation proved essential
Number of cases (%) 814 615 137 67 293
(97.7) (73.8) (16.4) (4.3) (35.2)
Principle applications Can of anterior or posterior SC Clearing apex with can of posterior SC Can, cup, jam of horizontal SC Cup, jam of anterior SC When procedure was not effective until oscillation applied; all cup and jam
SC, Semicircular canal; can, canalithiasis; cup, cupulolithiasis; ipsi, ipsilateral; contra, contralateral.
86.6% (group A) demonstrated significant improvement (Table 1). With 1 or 2 additional treatments, another 11.8% (group B) demonstrated significant improvement. Approximately 2% of patients did not respond to any treatment after undergoing 4 or more sessions (group C).
Primary Pathophysiology Analysis indicated the primary pathophysiology (Table 1) to be canalithiasis in 84.6%, cupulolithiasis in 11.2%, and canalith jam in 3.8%. In comparing the response to treatment, only 4.3% of cases with canalithiasis required more than 1 session to obtain significant improvement, whereas 57.0% of cases with cupulolithiasis required 2 or 3 sessions, and 7.5% were not improved after 4 or more sessions.
Semicircular Canal of Involvement Based on the nystagmus pattern and the simultaneous position/positioning of the patient, the SC location of the abnormal particles was assessed (Table 2). The posterior SC was involved in 66.4% of cases, horizontal SC in 10.1%, anterior SC in 2.3%, and multiple SCs in 21.3%. These results are generally in agreement with others.13,14 In comparing the effectiveness of treatment in the 3 SCs, regardless of the form of lithiasis, only 1 treatment session (with a follow-up validation session) was required for involvement of either a posterior SC (99.3% of cases) or for a horizontal SC (89.2%). However, 2 or 3 sessions were required with involvement of the anterior SC in 36.8%, or multiple SCs in 44.1%. In addition, multiple SCs were involved in all patients who failed to show lasting improvement.
No Surgery Required During the period of this study, none of the 833 subjects were treated with surgery, although this option was offered for a few cases that were subject to frequent recurrences or demonstrated no improvement. Previously, while treating these conditions at the POC with manual maneuvers, approximately 5% were being treated with surgery (singular neurectomy or canal plugging).
DISCUSSION This study indicates that, given optimal methodology and equipment for undertaking RMs, better results can be achieved than were previously realized. Unfortunately, the resolution rates for the specific variants when treated with manual maneuvers have not been addressed in the literature, and therefore a direct comparison is not feasible. Nevertheless, the aforementioned estimate of less than 25% resolution for all uncategorized variants was clearly eclipsed in the present study. In fact, many patients had failed treatment with manual maneuvers attempted elsewhere and had been referred to the POC for evaluation and treatment with this special modality. Another significant factor was the lack of surgery (none in 833 cases) required for these conditions. Although several surgical procedures14-16 are in use for treatment of labyrinthine lithiasis that is refractory to conservative treatment, the results in this study suggest surgery should rarely be indicated.
Improved Nystagmus Observation In our experience, prior to the use of the MAC/IRV combination, when attempting to use IR video goggles during manual maneuvers, it was frequently difficult to maintain a stabilized image of the eye. However, when using IR video goggles with the positioning chair, this problem was minimized as the whole body was moved rather than just the head, and therefore an unfettered view of the eye position could be maintained throughout. The value of this improved nystagmus observation throughout RMs cannot be overemphasized, because most abnormal nystagmus induced by position or positioning is secondary to displaced otoliths or other dense material that directly or indirectly affects SC physiology.1,11,17 Thus, nystagmus observation provides information crucial to determine the ongoing status of a dynamic pathophysiologic process. This ongoing nystagmus observation can determine, for instance, when conversion to another canal has taken place, the approximate location of the particles within the canal(s), best treatment pathways, and whether all the particles have cleared the canal. Without this information, the operator
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BPPV and Variants: Improved Treatment Results . . .
is taking a less-than-scientific guess as to the ongoing pathophysiological status relative to the canal(s) of involvement.
Unlimited Maneuverability The unlimited maneuverability provided by the positioning apparatus made possible the special, condition specific maneuvers that were necessary in many cases to obtain resolution. For instance, the value of a controlled, 360-degree rotation in any plane was illustrated in diagnosing and treating cases in which, by our analysis, the repositioning of particles was blocked at the posterior SC apex. The typical case had failed attempts at CRP elsewhere and then failed to respond initially at the POC to routine CRP measures. Analysis on the MAC/IRV system localized the problem through accomplishing a backward “360” while keeping the target SC coplanar with gravity. This maneuver induced a torsional nystagmus that would suddenly cease at a point where the patient’s head was generally between 120 to 180 degrees back from upright; then, on continuing to rotate the SC through 270 degrees, there would be a reversal of the torsional nystagmus with retention of the same axis of rotation. This reversal is interpreted as an indication that particles had failed to pass the apex and were gravitating back toward their original location. This apex blockage problem was usually resolved by providing a similar backward 360-degree flip while the head was turned 45 degrees to the ipsilateral side, but more slowly and with oscillation applied. This was timed to keep the particles moving toward the utricle throughout the rotation, as indicated by continuing nystagmus in the same direction. If necessary, the SC was rotated so that the obstructed segment of the posterior PSC was oriented vertically, whereupon broad angular back-andforth movements of the chair were used to impart longitudinal forces, in addition to the gravitational forces, to the particles. The value of this 360-degree capability is also illustrated in the various frontward flips, backward flips, and rolls discussed above.
Ease and Safety of Use Another advantage of the MAC/IRV combination is the ease with which the operator can move the patient through multiple complex maneuvers without this task interfering significantly with the operator’s simultaneous task of monitoring the nystagmus and formulating a response thereto. This ease of use is also illustrated by some complicated cases in which numerous maneuvers were necessary within a single session to accomplish effective treatment. These have sometimes run to over 40 sequential changes of position, with testing, treating, and retesting numerous times. If attempted manually, such
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extensive maneuvering would be exhausting for both the patient and operator. The other significant factor with manual maneuvers is the risk to medical personnel in lifting and turning patients, particularly patients who are overweight or debilitated. With a positioning chair, this risk is significantly minimized.
CONCLUSION In the our opinion, after carrying out RMs by manual means over a period of years, we find that the MAC/IRV combination provided definite advantages in terms of convenience, maneuverability, 360-degree capability, precise orientation, improved safety, all-inclusive nystagmus observation, and electronic documentation. The value of this type of hardware to the diagnosis and treatment of BPPV and variants, especially complicated cases, has been well demonstrated by this study. This combination has produced improved diagnostic and treatment results, as well as several insightful observations that can be applied to RMs carried out by any means. The fact that a significant proportion of cases in this study had been referred for evaluation and treatment by this modality after manual RM failure speaks well for the efficacy of this modality. Arrangements are underway to make this equipment, with appropriate software, available on the market. Estimates place its cost somewhat above the level of a rotational chair with associated software, but it appears to have far greater potential clinical value. Pending an indepth cost-benefit analysis, the feasibility of equipment with similar capability for general deployment at tertiary centers for management of vestibular conditions remains unproven, but the POC experience has been very positive.
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