Have cranio vertebral junction anomalies been overlooked as a cause of vertebro-basilar insufficiency

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Have cranio vertebral junction anomalies been overlooked as a cause of vertebro-basilar insufficiency

  1. 1. HAVE CRANIO-VERTEBRAL JUNCTION ANOMALIES BEEN OVERLOOKED AS A CAUSE OF VERTEBRO-BASILAR INSUFFICIENCY? Deepak Agrawal, Naveen K Departments of Neurosurgery and *Nuclear medicine, All India Institute of Medical Sciences, New Delhi-110029
  2. 2. <ul><li>BACKGROUND </li></ul><ul><li>association of VBI with CVJ anomalies is severely underestimated </li></ul><ul><li>x-rays of the Cx spine are done in only 30% of pts with VBI & only 11% pts have proper flex n /ext n x-rays done </li></ul><ul><li>Lorenstan KJ, Schrospshire LC, Ahn HS. Congenital odontoid aplasia and posterior circulation stroke in childhood. Ann Neurol 1988;23-410-413 </li></ul>
  3. 3. <ul><li>BACKGROUND </li></ul><ul><li>posterior circulation ischemia has a higher morbidity and mortality </li></ul><ul><li>Fifty percent of these patients who are managed conservatively progress to develop infarction </li></ul>
  4. 4. <ul><li>BACKGROUND </li></ul><ul><li>Diagnosing even a percentage of the patients with VBI as having CVJ anomalies may have major therapeutic & prognostic implications. </li></ul>
  5. 5. <ul><li>Aims and Objectives : </li></ul><ul><li>Using 99Tc ECD brain SPECT to document the presence of posterior circulation cerebral ischemia in patients with CVJ anomalies and correlate with symptoms of VBI. </li></ul>
  6. 6. <ul><li>PROSPECTIVE STUDY DONE OVER A SIX MONTH PERIOD </li></ul>
  7. 7. <ul><li>STUDY DESIGN </li></ul>19 PATIENTS WITH FIXED AAD Clinical assessment & Brain SPECT on admission CONTROL GROUP (7 PTS) VBI GROUP (12 PTS) TOO + PF TOO + PF Rpt SPECT at 4 weeks Rpt SPECT at 4 weeks
  8. 8. <ul><li>VBI GROUP </li></ul><ul><li>Pts with features suggestive of VBI (Drop attacks, episodic vertigo, visual disturbances and dysarthria) </li></ul><ul><li>CONTROL GROUP </li></ul><ul><li>patients without symptoms of VBI </li></ul>
  9. 9. <ul><li>Operative procedure </li></ul><ul><li>combined TOO and Occipito-cervical fusion from occiput to C3, using contoured loop and sublaminar wiring with bone graft placement. </li></ul><ul><li>Both procedures were carried out consecutively in a single sitting. </li></ul>
  10. 10. <ul><li>Patients with reducible AAD, requiring only occipito-cervical fusion were excluded from the study to maintain uniformity. </li></ul><ul><li>Postoperatively the neck was immobilized using a philadelphia collar for a period of three months. </li></ul>
  11. 11. <ul><li>SPECT scanning was done using 99Tcm-ECD on a dual headed GE 'Varicam' scanner. </li></ul><ul><li>The final data was displayed on a 10 grade color scale and semi quantitative analysis performed. </li></ul>SPECT
  12. 12. <ul><li>Regional cerebellar perfusion <10% of contralateral lobe, or in case of bilateral involvement, less than 20% of basal ganglia </li></ul>ABNORMAL SPECT SCAN
  13. 13. <ul><li>OBSERVATIONS </li></ul><ul><li>Radiology </li></ul><ul><li>AAD 19 </li></ul><ul><li>BI 15 </li></ul><ul><li>Occipitalisation of atlas 14 </li></ul><ul><li>kippel-feil anomaly 9 </li></ul><ul><li>cerebellar infarcts 2 </li></ul><ul><li>(Both in VBI group) </li></ul>
  14. 14. <ul><li>OBSERVATIONS ( VBI Group ) </li></ul><ul><li>Clinical features </li></ul><ul><li>Vertigo and drop attacks 10 </li></ul><ul><li>Incoordination 8 </li></ul><ul><li>visual symptoms 4 </li></ul>
  15. 15. <ul><li>RESULTS </li></ul><ul><li>(Preoperative SPECT) </li></ul><ul><li>Decreased cerebellar perfusion in 75% (n=9) of the patients in the VBI group compared to 14% (n=1) in the control group </li></ul><ul><li>(p=0.019, fischer exact, 2 tailed). </li></ul>
  16. 17. <ul><li>RESULTS </li></ul><ul><li>Following surgery, five patients (55%) in the symptomatic group and none in the control group had improvement in cerebellar perfusion. </li></ul><ul><li>All five patients showing improvement on SPECT also had improvement in their symptoms of VBI following surgery </li></ul>
  17. 18. <ul><li>Two pts in VBI group developed meningitis in the postoperative period & had a further decrease in cerebellar perfusion on the follow up SPECT scan. </li></ul><ul><li>Another 2 pts in VBI group had cerebellar infarcts on MRI & did not show improvement in cerebellar hypoperfusion following surgery. </li></ul>
  18. 19. <ul><li>Pathogenesis VBI in CVJ Anomalies </li></ul>Chronic low grade micro-trauma Rptd flex/extn of vessel Intimal damage Thrombosis Embolisation
  19. 20. <ul><li>Clinical rarity of posterior circulation infarcts in CVJ anomalies could be due to : </li></ul><ul><li>Duplication of VA and the adequacy of the circulation of Willis </li></ul><ul><li>patients symptomatic for VBI are not routinely evaluated for CVJ anomalies which remain undiagnosed </li></ul>
  20. 21. <ul><li>In patients with CVJ anomalies currently used imaging modalities such as cervical spine x-rays and CT scans are not adequate to evaluate for vertebro-basilar ischemia </li></ul>
  21. 22. <ul><li>Ours is the only study of its kind documenting hypoperfusion in posterior circulation territory in patients with CVJ anomalies. </li></ul><ul><li>This hypoperfusion may represent a state of chronic VBI, expected in such patients & MAY BE REVERSIBLE following surgery. </li></ul>
  22. 23. <ul><li>CONCLUSIONS </li></ul><ul><li>Our study shows that rigid immobilisation (provided by occipito-cervical fusion in our patients) by itself may confer protection from VBI and direct repair of VA may not be necessary </li></ul>
  23. 24. <ul><li>CONCLUSION </li></ul><ul><li>We strongly recommend that in patients of VBI, a high index of suspicion should be kept for CVJ anomalies and x-rays of the cervical spine with flexion-extension views be done on all patients. </li></ul>
  24. 25. <ul><li>THANK YOU </li></ul>

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