1. Spinal cord protection in surgery of descending thoracic aorta Present by R1 康庭瑞

2. Case  55 y/o male, HTN for 20+ years with regular medical control for 5 years  Chronic dissecting aortic aneurysm type III noted for 5 years  Left chest pain for 1 week  Denied other systemic diseases  Laboratory data: within normal range

7. Case  Normal screening spirometry  2-D echocardiography: dilated aortic root(diameter 63mm) & LA, mild MR, good LV contractility  Planning: 1.Left post-lat thoracotomy 2. Femoral- femoral CPB 3. Hypothermia with circulation arrest and retrograde cerebral perfusion via high CVP 18~20mmHg by femoral artery perfusion and partial clamp of venous drain tube 4. Restore proximal aorta perfusion after proximal anastomosis through graft cannulation 5. Open distal anastomosis

11. Case  Cooling to 16 ℃  Partial bypass: 3hr25min  Total bypass: 2hr30min  Aortic cross clamp: ?min  Circulatory arrest: 20min  Double lumen  single-lumen ET tube  ICU  weaning and extubation on post-op day 3 without major complications

12. Consequences of aortic cross- clamping  Spinal cord ischemia  Vascular anatomy: single ant. spinal a. from vertebral a.  supply ant. 2/3 of spinal cord; pair of post. spinal a. from post. cerebellar a.  supply remainder of spinal cord  Spinal cord perfusion from: vertebral, deep cervical, intercostal, and lumbar a.  radicular a.  The largest radicular a. (artery of Adamkiewicz): origin from T9~12 intercostal a.  supply the majority of blood to the lower 2/3 of the spinal cord

13. Spinal cord ischemia  Paraplegia and paraparesis: major cause of morbidity and mortality after extensive TAAA repair  Incidence: 2~40%, depending on the site and the degree of aortic lesion, with/without dissection (2- fold), cross-clamp duration (less than 30min), ligation of the artery of Adamkiewicz, elevation in CSF pressure, reperfusion injury, perioperative hyperglycemia

14. Spinal cord perfusion pressure  CSF pressure increases during aortic clamping  “spinal cord compartment syndrome”  Reduction of CSF pressure improves SCPP  Lumbar drains  Combined with distal aortic perfusion

15. Result  CSF pressure was maintained at 10mmHg or less  148 nonemergent patients who received simple cross- clamping  105 with combined adjuncts, 43 with or without the addition of a single adjunct  0.9% vs 7% (p<0.04)

16. Result  2.6% vs 13.0%  Reduced immediate deficits, particularly paraplegia  Infrequent delayed neurologic deficits in both groups  The longer the ischemic time were, the greater the benefit afforded with CSFD

17. Conclusions  Significantly reduced the rate of neurologic deficit during nonemergent repair of descending thoracic aortic aneurysms  The recently reports had convinced most surgeons of the benefit of CSF drainage in descending thoracic aortic aneurysm

18. Other adjuncts  Selective cooling spinal cord via lavage of the epidural space: regional hypothemic (26 ℃ ) protection of at-risk thoracolumbar cord  Corticosteroid, thiopental, NMDA antagonist, papaverine

19. Complications of lumbar drainage after TAAA repair  Postoperative lower extremity neurologic deficit: result of thromboembolic or delayed ischemic complication or resulting from lumbar drainage  Intradural hematoma: 3.2% in this study  CT, MRI

20. Hypothermic cardiopulmonary bypass and circulatory arrest  Methylprednisone and thiopental are given during the period of cooling to 15 ℃  Circulatory arrest intervals: mean, 38min  Postoperative neurologic injury: 2.7%  Conclusion: hypothermic circulatory arrest offers certain advantages over other techniques and using of other adjunctive measures is not necessary

21. References  Hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoraco- abdominal aorta. Annals of thoracic surgery.74(5):S1885- 7,2002 Nov.  Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial. Journal of vascular surgery.35(4):631-9,2002 Apr.  Thoracoabdominal aneurysm repair: results with 337 operations performed over a 15-year interval. Annals of surgery.236(4):471-9,2002 Oct.  Complications of lumbar drainage after thoracoabdominal aortic aneurysm repair. Journal of vascular surgery.34(4):623-7,2001 Oct.

22. Thanks for your attention ！