Translating the Biomechanics of Benign Paroxysmal Positional Vertigo Combined Sections Meeting Las Vegas, NV February 3-6, 2014

Transcription

1 Translating the Biomechanics of Benign Paroxysmal Positional Vertigo to the Differential Diagnosis and Treatment Combined Sections Meeting Las Vegas, NV February 3-6, 2014 Richard Rabbitt, PhD, University of Utah, Salt Lake City, UT Janet O. Helminski, PT, PhD, Midwestern University, Downers Grove, IL Janene Holmberg, PT, DPT, NCS, Intermountain Hearing and Balance, Salt Lake City, UT

2 Translating the Biomechanics of Benign Paroxysmal Positional Vertigo to the Differential Diagnosis and Treatment Objectives: The participants will be able to: (1) Describe normal fluid dynamics, afferent firing, and anatomical alignment of the semicircular canals. (2) Describe the pathological biomechanics of BPPV. (3) Interpret patterns of nystagmus observed during positional testing and particle repositioning maneuvers. (4) Determine the ideal particle repositioning maneuver based on biomechanics of BPPV.

3 Normal Anatomy and Physiology of the Semicircular Canals

4 MRI of Right Membranous Labyrinth and Vestibular N. Utricle Saccule Vestibular Nerve Ampulla LC Ampulla PC chlea_and_vestibular_system_115700_maip3.png

5 Semicircular Canals-Crista Ampullaris and Cupula The fluid filled canals normally act to detect rotation of the head. Rotation of the head causes deflection of the sensory hair cells located within the crista ampullaris. The hair cells are embedded within a gelatinous membrane the cupula. Photomicrograph of crista ampullaris and its cupula. Note that the cupula is attached to the ampullary roof. (Gacek, 2008)

6 Hair Cells Sensory Transducer Hair cells consist of stereocilia and kinocilium. Defection of hair cells: AmpulloFUGAL- towards the kinocilium - excites CN VIII. AmpullaPEDAL - away from the kinocilium - inhibits CN VIII

7 Position of Kinocilium within the Ampulla Effects Neural Firing of CN VIII In the vertical canals: flow of endolymph away from ampulla excites the nerve. flow towards the ampulla inhibits the nerve. In the lateral canals: flow of endolymph towards the ampulla excites the nerve flow away from the ampulla inhibits the nerve. Each canal generates eye movements in opposite directions.

8 Orientation of Initial Ampullary Segment in the Upright Position Illustrated for Left Membranous Labyrinth PC - 20 below horizontal. AC Ampullary Segment AC almost vertical (70 with respect to earth horizontal). LC naso-occiptal angle. LC Ampullary Segment Bertholon P et al. J Neurol Neurosurg Psychiatry 2002;72: by BMJ Publishing Group Ltd. PC Ampullary Segment

9 Comparison of Human Canal Planes using MRI Orientation of Canal Planes PC - 51 from the sagittal plane 35 AC - 35 from the sagittal plane 51 Suzuki K., Masukawa a., et al., 2010

10 Mathematical Model of Human Semicircular Canal Geometry Based on CT Scans Canal planes are curvilinear not flat. Bradshaw AP, Curthoys IS, Todd MJ, Magnussen JS, Taubman DS, Aw ST, Halmagyi GM. A Mathematical model of human semicircular canal geometry: a new basis for interpreting vestibular physiology. JARO. 2010;11:

11 Canal Influences Pair of Extraocular Muscles Extraocular muscles that receive direct excitatory contributions (Illustrated for left eye). Anterior Canal influences i-superior Rectus C-Inferior Oblique AC LC PC Posterior Canal influences i-superior Oblique C-Inferior Rectus HC LC Lateral Canal influences i-medial Rectus C-Lateral Rectus AC PC

12 Vestibular Ocular Reflex Pathway Excitatory and Inhibitory Connections. Wikimedia.org

13 Lateral Canal Stimulation Right Left MacDougall, McGarvie, Halmagyi, Curthoys, and Weber, 2013

14 RALP Stimulation Right Anterior Left Posterior Right Left MacDougall, McGarvie, Halmagyi, Curthoys, and Weber, 2013

15 LARP Stimulation Left Anterior Right Posterior Right Left MacDougall, McGarvie, Halmagyi, Curthoys, and Weber, 2013

16 Dr. Rabbitt Slides 1-22

17 Pathological Biomechanics of Benign Paroxysmal Positional Vertigo Saccule Utricle

18 Maculae Hair Cells, Otolith Membrane, Otoconia Otoconia weights the sensory membrane. The weighted sensory membrane acts to detect gravitational forces on the head. Increased magnification of macula. Note hair cells and otolith membrane. anization_of_the_inner_ear.htm Electron Microscope of Calcite particles (otoconia) (Everett, Belyantseva, et al, 2001)

19 Otoconia Otoconia composed of organic matrix and minerals (calcium carbonate). The matrix is identical to matrix of otolithic membrane. ntent/10/2.cover-expansion Intact human otoconia surrounded by organic matrix (Walther, Wenzel et al., 2013)

20 Age-Related Changes of the Morphology of Human Otoconia Stages of degeneration of human otoconia. Otoconia bodies are pitted, fissured, penetrated or broken into several fragments. (Walther, Wenzel, et al.., 2013).

21 Age-Related Changes of the Morphology of Otoconia Utricular Macula A. Middle-aged rat. B. Aged rat. Giant otoconia outer margin. A B Field emission scanning electron microscopy (FESEM) micrographs. Scale bar = 100µm. Jang, Hwang, Shin, Bae, Kim, 2006

22 Age-Related Changes of the Morphology of Otoconia A Linking filaments A. Interconnecting fibrils intact human otoconia (Walther, Wenzel, et al.., 2013). B. Weakened and broken fibrils in aged rats (Jang, Hwang, Shin, et al., 2006) Field emission scanning electron microscopy (FESEM) micrographs. Scale bar = 2µm.

23 Mechanisms of BPPV Otoconia that normally weights the membrane becomes dislodged and settles into the canals changing the dynamics of the canals.

24 Model of Cupulolithiasis Bullfrog labyrinth otoconial mass on cupula. Kitajima, 2012

25 Characteristics of Ocular Nystagmus Model of Cupulolithiasis Brief latency before onset of nystagmus because of weight of the particles on the PC cupula (Rajguru et al., 2004). Maintained activation of PC when the orientation of the head is changed relative to gravity (Rajguru et al., 2004). The effect builds up gradually over time to its value (20 s) (Hain,et. al., 2005). Any reduction in afferent input would be the result of adaptation by the hair cell afferent complexes (Rajguru et al., 2004). The same otoconia produce only 1/3 as much nystagmus as canalithiasis (Rajguru et al., 2004; Hain, et. al., 2005). Otoconia attached to cupula Reorientation of the canal relative to gravity deflects the cupula. (Korres et al., 2004)

26 Model of Canalithiasis Bullfrog labyrinth otoconia inserted into PC. Kitajima, 2012

27 Model of Canalithiasis Characteristics of Ocular Nystagmus Latency movement of detached otoconia through the ampulla (Rajguru et al., 2004; Hain et. al., 2005). A group of smaller particles showed longer latencies and larger responses (up to 80 s) than a single large particle of the same total mass (Rajguru et al., 2004). Takes 25 s for an otoconium to traverse one quarter of the canal (Hain et al., 2005). Small particles in constant contact with the wall while it sediments produces no nystagmus (Hain et al., 2005)

28 Model of Canalithiasis and Cupulolithiasis Bullfrog labyrinth otoconial mass in long arm of PC and on cupula. Kitajima, 2012

29 Dr. Rabbitt Slides 23-30

30 Positional Testing

31 Diagnosis of BPPV Clinical Practice Guidelines American Academy of Otolaryngology Head and Neck Surgery (Bhattacharyya et al., 2008) and American Academy of Neurology (Fife et al., 2008). Diagnosis based on both: A. History B. Findings on Positional Testing: Subjective (Symptoms) Objective (Nystagmus)

32 History Critical to Differential Diagnosis Process If getting out of bed and rolling over in bed is positive, patient 4.3 times more likely to have BPPV (Whitney, Marchetti, & Morris, 2005). If vertical canals involved, symptoms evoked when the patient: Looks up (top shelf syndrome PC involved) Moves head quickly Bends Bends forward to read (AC involved) If LC involved, symptoms evoked when the patient: Checks mirrors while driving Turns head in the horizontal plane while ambulating Bend forward in pitch plane

33 Dix-Hallpike Test (DHT) Patient wears Frenzel goggles or videooculography to prevent visual suppression of ny. Avoid use of vestibular suppressant medication that suppresses ocular ny. Maintain each position for at least 45 s. Re-evaluate >24 hours after the initial treatment procedure to avoid the fatiguing response (von Brevern et al., 2006). Psychometrics (Halker, Barrs, et al., 2008) Estimated sensitivity 79% (95% CI 65-94) Estimated specificity 75% (95% CI ) Horizontal Vertical DHT - illustrated for head right position only (A-B). Illustrated eye position traces (C).

34 Alternative to DHT - Sidelying Test (Cohen, 2004). Evaluates sensitivity of PC and AC if patient is unable to lie supine or move into neck extension. Same positions as Brandt-Daroff Exercises (Brandt et al, 1980).

35 Findings on DHT: Diagnostic Criteria for PC-BPPV Vector of PC ocular nystagmus primarily torsional (towards the dependent ear) and upward directed (Aw et al., 2005). Characteristics of Nystagmus 1- to 40- second latency before the onset of vertigo and nystagmus (Brandt et al, 1980; Epley, 1980; Herdman, 1990). Vertigo and nystagmus < 60 seconds in duration (Baloh et al., 1993). Fatigues with repeated positioning (Baloh et al., 1993). Debris Right PC Debris Right PC

36 Findings on DHT Suggest PC-BPPV Pattern of Nystagmus suggests Cupulolithiasis

37 Findings on DHT Suggest PC-BPPV Pattern of Nystagmus suggests Canalithiasis Debris within Ampulla

38 Findings on DHT Suggest PC-BPPV Pattern of Nystagmus suggests Canalithiasis Debris within Long Arm

39 Findings on DHT: Diagnostic Criteria for AC-BPPV Vector of AC Ocular Nystagmus: Primarily downward directed Small torsional component or no torsion (50% of patients). Direction of torsion towards ear involved. geotropic-axis of the lowermost ear or apogeotropic-axis of the uppermost ear Characteristics of Nystagmus (Berthonlon et al., 2002) 1- to 5- second latency before the onset of vertigo and nystagmus. Vertigo and nystagmus < 60 seconds in duration. Fatigues with repeated positioning. Key: Right Head Hanging Position may activate both AC s.

40 Findings on DHT: Diagnostic Criteria for AC-BPPV The straight head hanging position (30 of extension) of the DHT enables otoconia to clear the curvature of the long arm of the AC. A minimum of 60 of extension is needed to clear the curvature of the AC (Kim and Amedee, 2002; Crevits, 2005). 4

41 Findings on DHT Suggest AC-BPPV Side Involved Unknown

42 Findings on DHT Suggest AC-BPPV Torsion Towards Involved Ear

43 Dix-Hallpike Test (DHT) Key: To evaluate the PC and AC the head needs to be extended below the horizon to evoke nystagmus. DHT - illustrated for head right position only (A-B).

44 Dr. Rabbitt Slides 31-40

45 Particle Repositioning Maneuvers for Posterior Canal BPPV

46 Critical Steps for Successful Rx of PC-BPPV Canalith Repositioning Procedure (CRP) Modified Epley Maneuver Initial position adequate neck extension (head below horizon) to allow otoconia to settle into the long arm of the canal. Maintain neck extension during initial roll (B-C) to enable debris to roll away from ampulla. A 180 turn of the head is required to effectively clear the debris (B and D). (Rajguru, Ifediba et al., 2004). CRP - illustrated for treatment of right PC.

47 Critical Steps for Successful Rx of PC-BPPV Canalith Repositioning Procedure (CRP) Modified Epley Maneuver The head may be elevated 15 from the horizon in position D to prevent canal conversion to the AC and for comfort. The patient returns to sitting from lying on the uninvolved side. The head is flexed 36 in the chin down forward position to allow debris to settle lowest part of utricle. (Rajguru, Ifediba et al., 2004). CRP - illustrated for treatment of right PC.

48 Critical Steps for Successful Rx of PC-BPPV Canalith Repositioning Procedure (CRP) Modified Epley Maneuver Key to Success: Position of plane of PC relative to gravity not speed. CRP - illustrated for treatment of right PC.

49 If Patient Can t Tolerate Modify CRP Use Tilt Table Use tilt table to position canal plane within plane of gravity maintaining position of head relative to trunk and modifying position of body.

50 Pattern of Nystagmus Predicts Outcome of CRP - Successful Resolution

51 Pattern of Nystagmus Predicts Outcome of CRP Successful CRP. The angular velocity of the debris is always in the same direction causing an orthotropic pattern of ny (Korn, Dorigueto, et al, 2007).

52 Pattern of Nystagmus Predicts Outcome of CRP - Failure - No Resolution

53 Pattern of Nystagmus Predicts Outcome of CRP Failed CRP. The angular velocity of the debris reverses direction causing a reversal in the direction of ny (Korn, Dorigueto, et al, 2007).

54 Average Short Term Success Rate of CRP Average short term success rate of Canalith Repositioning Procedure in RCT(*) and quasi RCT (Helminski, et. al., 2010). Study Number resolved/ Number in study Percent Resolve Odds Ratio - Confidence Intervals Lynn et al., 1995* 16/ ( ) Von Brevern et al., 2006* 28/ ( ) Froehling et al., / ( ) Sherman et al., / ( ) Average 87/ Note: Variability in study by Froehling et al., 2000 may be due to clinical expertise of the study personnel.

55 Liberatory or Semont Maneuver (Semont, Freyss et al. 1988) Illustrated for treatment of the left PC (Radtke et al., 2004)

56 Liberatory or Semont Maneuver (Semont, Freyss et al. 1988) Liberatory Maneuver. The duration of the 180 whole-body swing needs to be less than 1.5 seconds (Faldon and Bronstein, 2008). Slow 180 acceleration traces a counterclockwise path - particles trapped behind cupula. Fast 180 acceleration plots a complete clockwise rotation - particles evacuated. 56

57 Liberatory Maneuver (Semont, Freyss et al. 1988) Duration < 1.5 seconds. 5 7

58 Pattern of Nystagmus Predicts Outcome of LM: Successful Resolution

59 Pattern of Nystagmus Predicts Outcome of LM: Failure No Resolution

60 Average Short Term Success Rate of Liberatory Maneuver Randomized controlled trials have evaluated the effectiveness of the Liberatory maneuver versus a control. Limited number of studies suggest LM more effective than a control. Study Number resolved/ Number in study Percent Resolve (%) Odds Ratio - Confidence Intervals Mandala et al., 2012 LM Control 151/174 0/ ( ) Chen et al, 2012 LM Control 55/65 9/ (12-88)

61 Comparison of CRP versus Liberatory Manuever Quasi RCT at short term follow-up of 1 week (Helminski, et. al., 2010) Study/Intervention Groups Number resolved/ Number in study Percent Resolve (%) Odds Ratio - Confidence Intervals Massoud et al, 1996* CRP LM 43/46 46/ ( ) Soto Varela et al, 2001* CRP LM 30/42 26/ ( ) Radtke et al., 2004** Self-admin. CRP Self-admin. LM 35/37 19/ ( ) Tanimoto et al., 2005* CRP only CRP+Self-admin.CRP 28/39 36/ ( ) * Standard treatment CRP. ** Standard treatment self-administered CRP.

62 What About Brandt-Daroff Exercsies?

63 Evidence does not Support Use of Brandt-Daroff Exercises as Primary Treatment of BPPV Debris moved within a 90 segment of the canal. A 360 turn of the head in the plane of the canal is required to effectively clear the debris (Rajguru et al., 2004; Faldon et al., 2008). Daily routine of Brandt-Daroff exercises does not affect the time to recurrence or rate of recurrence of BPPV (Helminski, et al., 2005). May cause multi-canal BPPV.

64 Evidence does not Support Use of Brandt-Daroff Exercsies as Primary Treatment of BPPV Randomized controlled trial have evaluated the effectiveness of the Brandt-Daroff exercises versus self-administered particle repositioning procedures and control. Findings suggest Brandt- Daroff exercises are as effective as a control at 1 week (Zhang et al., 2012). Study Number resolved/ Number in study Percent Resolve (%) χ 2 Zhang et al., 2012 self-administered CRP self-administered LM BD Control 39/45 23/43 14/40 6/ , p>0.05* *Brandt-Daroff exercises versus control

65 Further Evidence needed to Support use as Secondary Treatment of BPPV Break-up debris to dissolve particles. Central habituation effect to resolve residual symptoms and phobia (Cohen, 2005).

66 Dr. Rabbitt Slides 41-50

67 Particle Repositioning Maneuvers for Anterior Canal BPPV

68 Maneuvers Designed for AC-BPPV Neck Extension - If Side Involved is Unknown A minimum of 60 of extension is needed to clear the curvature of the AC (Kim and Amedee, 2002; Crevits, 2005). Neck Extension (Helminski et al., 2007). The patient is brought into the recumbent position with the head extended over the edge of the table. The position is held for 2 minutes to provide adequate time for the debris to settle in the AC. The patient is returned to the upright position. The head is flexed 36 in the chin down forward position to allow debris to settle lowest part of utricle 6 8

69 6 9 Maneuvers Designed for AC-BPPV Neck Extension - If Side Involved is Unknown

70 Maneuvers Designed for AC-BPPV Forward Particle Repositioning Maneuver (Faldon and Bronstein, 2008). - If Side Involved is Known

71 Maneuvers Designed for AC-BPPV Forward Particle Repositioning Maneuver (Faldon and Bronstein, 2008). - If Side Involved is Known For Right AC - perform a 360 forward rotation around AC: Lie prone on elbows on the edge of mat. Turn head 45 towards the left. Bring head forward over the edge of the mat. Hold for 30 seconds. Turn head 90 towards the right into 45 of rotation right. Hold for 30 seconds. Roll towards right onto back into DHT - head right position. Hold for 30 seconds. Sit-up. The head is flexed 36 in the chin down forward position to allow debris to settle lowest part of utricle.

72 Maneuvers Designed for AC-BPPV Forward Particle Repositioning Maneuver (Faldon and Bronstein, 2008). - If Side Involved is Known

73 Positional Testing for Lateral Canal BPPV

74 Lateral Canal - BPPV Lateral Canal (LC) Ocular Nystagmus (McClure, 1985): paroxysmal linear-horizontal bi-directional-changing positional nystagmus transverse plane pitch (sagittal) plane 7 4 Transverse plane - right v. left Pitch plane - flexion v. extension

75 Ocular Nystagmus Associated with LC BPPV Ocular nystagmus may be geotropic or apogeotropic horizontal bidirectional changing positional nystagmus (DCPN). Ny is associated with vertigo. Supine - 90 of Cervical Rotation towards the Right Lateral Rectus Geotropic nystagmus Apogeotropic nystagmus Debris right LC Medial Rectus 75

76 Location of Debris within LC Illustrated for Right LC. Key: Direction of DCPN dependent on location of debris within the LC. Geotropic (geo) DCPN Debris located within long arm Apogeotropic (apo) DCPN Debris directly attached to the cupula (cupulolithiasis) on side adjacent to utricule or to long arm. OR Debris located within ampullary segment. Ampullary Segment Long arm Utricular Vestibular Annals of the New York Academy of Sciences Vol. 1164, 1Basic and Clinical Aspects of Vertigo and Dizziness Pages: Copyright The New York Academy of Sciences 76

77 Step 1: Determine Direction of Ny to Identify the Location of Debris within the LC Recumbent - Transverse Plane Supine Roll Test

78 Supine Roll Test Geotropic LC-BPPV Geotropic left LC BPPV: Head center - right beating. Head right - right beating with occasional ccw torsion. Head left very strong left beating. Right Left 78

79 Supine Roll Test - Geotropic Right LC-BPPV Roll LEFT Roll RIGHT Endolymph Away Otoconia Otoconia Endolymph Toward Away = (--) Canal Inhibit R canal = Ny L Toward = (+) Canal Excite R canal = Ny R Annals of the New York Academy of Sciences Volume 1164, Issue 1, pages , 21 MAY 2009 DOI: /j x

80 Supine Roll Test Apogeotropic Left LC-BPPV 8 0 Right Left

81 Supine Roll Test - Apogeotropic Right LC-BPPV Roll LEFT Roll RIGHT Otoconia Otoconia Otoconia Endolymph Away Endolymph Toward Toward = (+) Canal Excite R canal = Ny R Annals of the New York Academy of Sciences Volume 1164, Issue 1, pages , 21 MAY 2009 DOI: /j x Away = (--) Canal Inhibit R canal = Ny L

82 Step 2: Lateralization of LC-BPPV Recumbent - Transverse Plane Supine Roll Test Intensity of nystagmus Pseudo-Spontaneous Nystagmus Direction of nystagmus

83 Key: SRT - Intensity of Nystagmus Determines Side Involved Geotropic (geo) DCPN Side of greatest intensity of nystagmus side involved. Apogeotropic (apo) DCPN Side of least intensity of nystagmus side involved.

84 Pseudo-Spontaneous Nystagmus Illustrated for Right LC. Direction of pseudo-spontaneous nystagmus dependent on location of debris within the LC. Geotropic (geo) DCPN Ny beats away from involved ear. Cupular deflection inhibitory. Apogeotropic (apo) DCPN Ny beats towards involved ear. Cupular deflection excitatory. Ampullary Segment Long arm Utricular Vestibular Annals of the New York Academy of Sciences Vol. 1164, 1Basic and Clinical Aspects of Vertigo and Dizziness Pages: Copyright The New York Academy of Sciences 84

85 Pitch Plane Test - Differentially Diagnose LC - BPPV Key: LC Involved direction of ny gravity dependent. Cervicogenic or CNS Dysfuntion direction of ny dependent on position of neck. Head 30 Extension Debris settles towards occiput. Direction of nystagmus same as pseudo spontaneous nystagmus. Head 60 Flexion: LC-BPPV-Debris settles towards nose. Direction of nystagmus reverses direction of pseudo spontaneous nystagmus. Cervicogenic or CNS dysfunction. - Direction of nystagmus same as pseudo spontaneous nystagmus. Illustrated right LC

86 Diagnostic Criteria for LC - BPPV Lateral Canal Ocular Nystagmus Paroxysmal, linear-horizontal and bi-direction-changing positional nystagmus in the transverse and pitch plane (McClure, 1985). Characteristics of Nystagmus 1- to 2- second latency or no latency before the onset of vertigo and nystagmus (McClure, 1985). Vertigo and nystagmus > 60 seconds in duration (McClure, 1985) Does not fatigue with repeated positioning (Bisdorff and Debatisse, 2001). In most patients one side is more intense and a secondary reversal nystagmus is seen that is less intense but lasts longer (Steddin, Ing, and Brandt, 1996). 86

87 Particle Repositioning Maneuvers for Lateral Canal BPPV

88 Treatment of Geotropic LC BPPV Log Roll Manuever (Rajguru et al., 2005) Illustrated for right geotropic LC-BPPV.

89 Critical Steps for Successful Rx of Geotropic LC-BPPV Log Roll Begin treatment with the head rotated 90 towards the affected side. The neck may remain in neutral and does not need to be flexed 30. A 270 rotation about the longitudinal axis in the recumbent position successfully moves debris out of the canal into the utricular vestibule. In a prospective study, the short term success rate of the log roll maneuver was 71% (Nuti, et al., 1998). Log Roll - illustrated for treatment of right LC.

90 Treatment of Apogeotropic LC-BPPV Cupulolith Repositioning Maneuver (Kim, Jo, et al, 2011) Goal: To move debris located on side of cupula adjacent to utricular vestibule (4 th position) or to long arm (1 st position) into the vestibule. Procedure illustrated for right apogeotropic LC-BPPV: Each position maintained 3 minutes. Vibration applied for 20 s 1 st and 4 th position. Activity Restrictions. Sleep on uninvolved side. Key: Treats both sides of cupula.

91 Critical Steps for Successful Rx of Apogeotropic LC-BPPV Cupulolith Repositioning Maneuver Begin treatment towards the affected side. Do not use vibration if history of torn or detached retina Success Rate 97.4% (76/78) after 2 repetitions of maneuver.

92 Dr. Rabbitt Slides 51-55

93 What Happens to Debris Following Maneuver? Hypothesized: Break up into small enough particles for otoconia to dissolve in endolymph (Zucca, Valli, et al., 1998). Attach to vestibular dark cells surrounding utricular macula (Lim, 1976).