Ali Azizzadeh, MD, Tam T. T. Huynh, MD, Charles C. Miller III, PhD, and Hazim J. Safi, MD, Houston, Tex

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1 Reversal of twice-delayed neurologic deficits with cerebrospinal fluid drainage after thoracoabdominal aneurysm repair: A case report and plea for a national database collection Ali Azizzadeh, MD, Tam T. T. Huynh, MD, Charles C. Miller III, PhD, and Hazim J. Safi, MD, Houston, Tex Delayed neurologic deficits are an uncommon yet devastating complication of thoracoabdominal aortic aneurysm repair. The mechanisms involved in the development of delayed spinal cord ischemia remain ill defined. We report a case of complete reversal of delayed neurologic deficits with postoperative cerebrospinal fluid (CSF) drainage. After a thoracoabdominal aneurysm extent I repair, the patient experienced delayed paraplegia at 6 hours and again at 34 hours after the operation, with elevated CSF pressure (>10 mm Hg) on both occasions. Prompt CSF decompression completely reversed the neurologic deficits within hours after onset. The findings in this case further support the role of CSF drainage in spinal cord protection for patients who undergo thoracoabdominal aneurysm repair and make a plea for a national database collection. (J Vasc Surg 2000;31:592-8.) From the Department of Surgery, Methodist Hospital, Baylor College of Medicine. Competition of interest: nil. Reprint requests: Dr Hazim J. Safi, Department of Cardiothoracic and Vascular Surgery, The University of Texas at Houston Medical Center, MSB 1.214, 6431 Fannin, Houston, TX Copyright 2000 by The Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter /2000/$ /4/ doi: /mva The development of delayed neurologic deficits after thoracoabdominal aortic aneurysm repair involves a complex interplay of events that remain ill defined. Among the supportive interventions to remedy this problem (such as stabilization of systemic arterial pressure, steroid administration, and physical therapy), cerebrospinal fluid (CSF) catheter drainage has had the most impact. 1-3 We report a case of delayed-onset paraplegia that occurred twice in the same patient, after the repair of a thoracoabdominal aneurysm extent I, and that were both completely reversed with prompt CSF catheter decompression. It is thought that the spinal cord may be more susceptible to injury in the immediate postoperative course after thoracoabdominal aneurysm repair; hence close postoperative monitoring of CSF pressure and prompt catheter decompression would provide protection against delayed critical spinal cord ischemia. However, this rationale still needs to be tested more widely; therefore we propose a nationwide collection of data to further study the infrequent problem of delayed neurologic ischemia. CASE REPORT An 81-year-old man was diagnosed with a thoracoabdominal aneurysm of extent I (extending from just distal to the origin of the left subclavian artery to just above the origin of the left renal artery); the largest diameter measured 7.4 cm, on routine follow-up computed tomography scan of the chest and abdomen for a known chronic type B dissection. The patient had a history of hypertension but no discernable symptoms. On July 30, 1998, he underwent repair of the thoracoabdominal aneurysm with the use of a 26-mm woven Dacron tube graft to replace the aneurysm from just distal to the origin of the left subclavian to the level of the left renal artery, with patch reattachment of the celiac artery; superior mesenteric artery; right and left renal arteries; reimplantation of T9, T10, T11, and T12 thoracic intercostal arteries; and ligation of the T3, T4, T5, T6, T7, and T8 thoracic intercostal arteries. Distal aortic perfusion with a left atrial-to-left femoral artery bypass (BioMedicus pump; BioMedicus, Minneapolis, Minn) and CSF drainage (Cordis lumbar drain; Cordis Corp, Miami, Fla) were used as adjuncts to 592

2 Volume 31, Number 3 Azizzadeh et al 593 provide spinal cord protection, as previously described. 4 The bypass time was 81 minutes, and the aortic crossclamp time was 38 minutes. The patient received nine units of packed red blood cells, 25 units of cell savers, 11 units of fresh frozen plasma, and 8 units of platelets; and his hemodynamic profile remained stable throughout the operation. In the first hours after the operation, the patient responded appropriately to commands and was able to move all four extremities (Tarlov score 4; Appendix I). CSF pressure was monitored hourly and maintained below 10 mm Hg with periodic CSF drainage. On the postoperative hour 6, CSF pressure peaked to 17 mm Hg and the patient experienced paraplegia (Tarlov score 0; Fig 1, A). The lumbar catheter was noted to be kinked and was repositioned to allow continous CSF drainage. Within the next hour, the patient recovered full movement of both his legs (Tarlov score 4; Fig 1, A). Approximately 34 hours after the operation, however, CSF pressure increased to 12 mm Hg as the result of occlusion of the lumbar catheter, and the patient again lost complete leg motions (Tarlov score 0; Fig 1, A). After prompt replacement of the lumbar catheter, the patient regained full neurologic function within the next 12 hours (Tarlov score 4; Fig 1, A). The patient s profile remained hemodynamically stable throughout both periods of paraplegia and thereafter (Fig 1, B) in his postoperative course. Two units of packed red blood cells and 80 ml of fresh frozen plasma per hour were infused in the initial 36 hours after the operation. Afterwards, normal saline solution was infused at 80 ml/h as maintenance fluid until resumption of adequate oral intake. The hemoglobin levels ranged from 8.6 to 10.6 g/dl (hematocrit, ) during the first week. CSF catheter drainage was maintained until postoperative day 7 (average, 209 ml/24 h; range, ml/24 h). A magnetic resonance image scan of the spinal cord obtained on postoperative day 15 demonstrated no cord infarction (Fig 2). The patient was subsequently discharged on postoperative day 22 with complete neurologic function. DISCUSSION Delayed onset of neurologic deficits is an infrequent but devastating complication after thoracoabdominal aortic aneurysm repair. 2,5,6 The mechanisms involved in the delayed development of paraparesis and paraplegia remain ill-defined. 7,8 Like immediate neurologic deficits, delayed onset deficits are the result of an agglomeration of events leading to spinal cord ischemia and infarction. However, the gradual onset of tissue edema to a critical level is likely the cause of delayed decrease in spinal cord perfusion and manifestation of neurologic deficits. We and others have shown significant recovery of neurologic function in patients with delayed paraparesis and paraplegia, with spinal cord decompression using CSF catheter drainage. 1,2,6,8 The findings A B Fig 1. A, Correlation between CSF pressure and neurologic function. The patient had delayed onset paraplegia (Tarlov score 0) at 6 hours after the operation, with a CSF pressure of 17 mm Hg. With prompt CSF drainage, CSF pressure was lowered to below 10 mm Hg and the patient regained leg movements (Tarlov score 4) within the next hour. At 34 hours after the operation, the patient again became paraplegic (Tarlov score 4), with CSF pressure elevated to 12 mm Hg. Although the CSF pressure elevation was due to lumbar catheter occlusion, this was not recognized for 6 hours. A new lumbar drain was then inserted, and CSF drainage was reinstituted, with resolution of the neurologic deficits over the next 12 hours. Time-point zero denotes the time the patient was admitted to the intensive care unit. The different Tarlov scores are defined in Appendix I. B, Postoperative fluctuations in systolic arterial pressure (SBP) and mean arterial pressures (MAP). There were no significant changes in mean or systolic arterial pressures during the periods of neurologic deficits. Values shown are the mean ± SD. Time-point zero denotes the time the patient was admitted into the intensive care unit. * Duration of the first delayed paraplegia event; ** duration of the second delayed paraplegia event.

3 594 Azizzadeh et al March 2000 A Fig 2. Sagittal T 2 -weighted magnetic resonance images of the upper (A) and lower (B) spinal cord obtained on postoperative day 15 showed no evidence of infarction. Arrows denote the outline of the spinal cord. B in this case report further strengthen the link between CSF pressure and spinal cord perfusion. The delayed manifestations of paraplegia in the patient presented here were associated with increased CSF pressure as the result of malfunction of the lumbar catheter on both occasions, at 6 and at 34 hours after the operation. More importantly, prompt correction of CSF drainage and decompression completely reversed the neurologic deficits after both incidents. Conceptually, the increased CSF pressure in the rigid unyielding spinal column would lead to decreased cord perfusion and consequently cord ischemia, with the clinical manifestations of cord dysfunction. This is analogous to other more common clinical compartment syndromes, such as cerebral and extremity ischemia arising from increased compartmental pressure. Although the problem of delayed onset of neurologic deficits after thoracoabdominal aortic aneurysm repair has been recognized, studies on the involved mechanisms are lacking. 1,2,5,6,8 Currently, there are no effective methods of correcting delayed spinal cord dysfunction, other than cord decompression with CSF drainage. 6 Notwithstanding the complexity of factors that are known to contribute to the development of immedi-

4 Volume 31, Number 3 Azizzadeh et al 595 ate and delayed neurologic deficits, regulation of CSF pressure appears to be key in the maintenance of spinal cord perfusion. Although immediate spinal cord dysfunction may be directly linked to severe cord ischemia sustained during the surgical repair, delayed cord dysfunction appears to be related to more reversible causes of cord ischemia. This is in contradiction to the previously held belief that the problem of delayed onset neurologic deficits is beyond the surgeon s control. 5 Patients who undergo thoracoabdominal aortic aneurysm repair sustain variable degrees of spinal cord ischemia, depending on the extent of aneurysm, ischemic crossclamp time, ligation and reattachment of intercostal arteries, and whether or not adjuncts were used for spinal cord protection. 1,4-6,8 Somatosensory or motor-evoked potentials have been used to monitor spinal cord function during the operation However, this modality requires additional equipment, expertise, and adjunct CSF drainage. On the other hand, the rationale for the routine use of CSF pressure monitoring and drainage is that it is a simple modality and can provide prompt spinal cord decompression to prevent critical cord ischemia during and after an operation. Furthermore, we speculate that postoperative factors (such as variations in systemic arterial blood pressure, fluid, and blood products therapy) may influence CSF pressure and spinal cord perfusion more than previously suspected. One other possible cause of delayed paraplegia or paraparesis is the occlusion of one or more reattached or grafted intercostal arteries in the postoperative period. Although the incidence of postoperative occlusion of intercostal arteries is unknown, re-exploration may be considered if CSF decompression failed to reverse delayed neurologic deficits. 11 We herein propose a national database collection for the management of thoracoabdominal aortic aneurysms to study the pathophysiologic features of the infrequent but dreadful delayed neurologic complications. The proposed database protocol (Appendix II) is not intended to be comprehensive. Nevertheless, a nationwide collection of the pertinent database would help determine the key factors in the development of neurologic deficits and, consequently, better guide us in our search for the optimal method of spinal cord protection. REFERENCES 1. Hollier LH, Money SR, Naslund TC, Procter DC, Burhman WC, Marino RJ, et al. Risk of spinal cord dysfunction in patients undergoing thoracoabdominal aortic replacement. Am J Surg 1992;164: Hill AB, Kalman PG, Johnston KW, Vosu HA. Reversal of delayed onset paraplegia after thoracic aortic surgery with cerebrospinal fluid drainage. J Vasc Surg 1994;20: Safi HJ, Hess KR, Randel M, Iliopoulos DC, Baldwin JC, Mootha RK, et al. Cerebrospinal fluid drainage and distal aortic perfusion: reducing neurologic complications in repair of thoracoabdominal aneurysms types I and II. J Vasc Surg 1996;23: Safi HJ, Bartoli S, Hess KR, Shenaq SS, Viets JR, Butt GR, et al. Neurologic deficit in patients at high risk with thoracoabdominal aortic aneurysms: the role of cerebral spinal fluid drainage and distal aortic perfusion. J Vasc Surg 1994;20: Crawford ES, Mizrahi EM, Hess KR, Coselli JS, Safi HJ, Patel VM. The impact of distal aortic perfusion and somatosensory evoked potential monitoring on prevention of paraplegia after aortic aneurysm operation. J Thorac Cardiovasc Surg 1988;95: Safi HJ, Miller CC III, Azizzadeh A, Iliopoulos DC. Observations on delayed neurologic deficit after thoracoabdominal aortic aneurysm repair. J Vasc Surg 1997;26: Grum D, Svensson LG. Changes in cerebrospinal fluid pressure and spinal cord perfusion pressure prior to cross-clamping of the thoracic aorta in humans. J Cardiothorac Vasc Anesth 1991;5: Safi HJ, Winnerkist A, Miller CC III, Ilipoulos DC, Reardon MJ, Espada R, et al. Effect of extended cross-clamp time during thoracoabdominal aortic aneurysm repair. Ann Thorac Surg 1998;66: Jacobs MJHM, Meylaerts SA, de Haan P, de Mol BA, Kalkman CJ. Strategies to prevent neurologic deficit based on motor-evoked potentials in type I and II thoracoabdominal aortic aneurysm repair. J Vasc Surg 1999;29: Griepp RB, Ergin MA, Galla, JD, Klein JJ, Spielvogel D, Griepp EB. Minimizing spinal cord injury during repair of descending thoracic and thoracoabdominal aneurysms: the Mount Sinai approach. Semin Thorac Cardiovasc Surg 1998;10: Svensson LG. Management of segmental intercostal and lumbar arteries during descending and thoracoabdominal aneurysm repairs. Semin Thorac Cardiovasc Surg 1998;10: Submitted Apr 28, 1999; accepted Jul 15, 1999.

5 596 Azizzadeh et al March 2000 APPENDIX I. MODIFIED TARLOV SCOR- ING SYSTEM* Score Explanation 0 No lower extremity motions 1 Lower extremity motions without gravity 2 Lower extremity motions against gravity 3 Able to stand with assistance 4 Able to walk with assistance 5 Able to walk without assistance * Patients were tested for lower extremity motions with and without gravity, the ability to stand with and without assistance, and the ability to walk with and without assistance. The last stage of the test (walking without assistance) was omitted while the patients were still in the intensive care unit. Patients were given a score of 4 if they were able to walk with assistance, but not tested without assistance. APPENDIX II. DATABASE FOR THORA- COABDOMINAL AORTIC ANEURYSM REPAIR Please fill in blanks and forward database forms to: Hazim J. Safi, MD, 6550 Fannin, Smith Tower Suite #1603, Methodist Hospital, Houston, TX 77030, USA. (Forms can also be obtained from the same address and electronically at hsafi@bcm.tmc.edu) See Section VIII for definitions and abbreviations. VIII. DEFINITIONS and ABBREVIATIONS a, Artery ave, Average CSF, Cerebrospinal fluid CVA, Cerebrovascular accident Delayed neurologic deficits, Onset of paraplegia or paraparesis after the patient is observed to have had normal neurologic function on awakening from anesthesia FFP, Fresh frozen plasma Immediate neurologic deficits, Paraplegia or paraparesis observed as the patient is awakened from anesthesia inf, Inferior lt, Left PRBC, Packed red blood cells pulm, Pulmonary rt, Right T, Temperature TIA, Transient ischemic attack

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7 598 Azizzadeh et al March 2000 APPENDIX III. CLASSIFICATION OF THORACOABDOMINAL ANEURYSM EXTENT Extent Explanation I II III IV V From distal to the left subclavian artery to proximal to above the renal arteries From distal to the left subclavian artery to below the renal arteries From the sixth intercostal space to below the renal arteries From the diaphragmatic hiatus to the aortic bifurcation (total abdominal) From the sixth intercostal space to above the renal arteries