Prevention of spinal cord ischaemic complications after thoracoabdominal aortic surgery

Ventriculoperitoneal Shunt Malfunction, a Rare Cause of Paraplegia after Kyphosis Correction: A Case Report and Literature Review

Ventriculoperitoneal shunt (VPS) malfunction after kyphosis surgery in 12-year boy caused a sudden hydrocephalus which increased cerebrospinal fluid pressure within the spinal cord and decreased cord perfusion. Spinal cord at apex of deformity was vulnerable to ischemia which caused paraplegia. The ischemic event was reversible after re-insertion of the VPS.

Study Design.

Case report and literature review.

Objective.

The aim of this study was to report a rare case of hydrocephalus due to ventriculoperitoneal shunt (VPS) malfunction following kyphosis correction that resulted in paraplegia in the postoperative period. The available English literature to explain the possible cause of paraplegia is reviewed.

Summary of Background Data.

Twelve-year male child presented with a severe dorsal kyphoscoliosis deformity with spastic paraparesis since 4 months. The lower extremities had grade-2 power and spasticity. The sensation was reduced below D9. The deep tendon reflexes were exaggerated with ankle clonus. Bowel-bladder had urgency and frequency. The radiographs and CT showed D6-7 hemi-vertebra with complex kyphoscoliosis deformity. magnetic resonance imaging showed a stretching cord at D6-7 due to 92° angular kyphosis. The somatosensory evoked potential showed posterior column involvement. The VPS was placed for hydrocephalus at 4 months of age. The shunt remained functioned throughout childhood.

Methods.

He underwent posterior vertebral column resection and kyphosis correction surgery. Postoperative CNS function was normal. Neurology was status quo. After 20 hours, the boy appeared irritable, confused with a headache and repetitive vomiting (Glasgow coma scale: 7-8/15). Computed tomography brain showed dilated both ventricles with left shunt in situ. Immediate re-shunting was done from right side. The CNS status improved dramatically and regained consciousness. Neurology deteriorated to grade-0 with increased spasticity and further decreased sensation below D9. The spinal causes (hematoma, implant malposition, syrinx) were ruled out.

Results.

Delayed neurological recovery was seen at 6th week after shunt surgery. The Rapid motor march was observed and became independent ambulatory at 12th week. At 6 months, he improved up-to grade4 power with grade 2 spasticity which maintained at 2 years.

Conclusion.

VPS blockage caused a sudden hydrocephalus which increased CSF pressure within the spinal cord and decreased cord perfusion. Spinal cord at apex of deformity was vulnerable to ischemia which caused paraplegia.

Level of Evidence: 5

Spinal cord protection in thoracoabdominal aortic aneurysm surgery: a multimodal approach

Spinal cord injury (SCI) is one major complication of open and endovascular thoracic and thoracoabdominal aortic aneurysm repair. Despite numerous neuroprotective adjuncts, the incidence of SCI remains high. This review article discusses established and novel adjuncts for spinal cord protection, including priming and preconditioning of the paraspinal collateral network, intraoperative systemic hypothermia, distal aortic perfusion, motor- and somatosensory evoked potentials and noninvasive cnNIRS monitoring as well as peri- and postoperative drainage of cerebrospinal fluid. Regardless of the positive influence of many of these strategies on neurologic outcome, to date no strategy assures definitive preservation of spinal cord integrity during and after aortic aneurysm repair.

Risk of spinal cord ischemia after fenestrated or branched endovascular repair of complex aortic aneurysms

OBJECTIVE

The aim of our study was to analyze the incidence of spinal cord ischemia (SCI) in patients presenting with complex aortic aneurysms treated with endovascular aneurysm repair (EVAR) and to identify risk factors associated with this complication.

METHODS

A retrospective study was undertaken of prospectively collected data including patients presenting with complex aortic aneurysm (pararenal abdominal aortic aneurysm and thoracoabdominal aortic aneurysm) treated with fenestrated EVAR (F-EVAR) or branched EVAR (B-EVAR). The primary end point was the incidence of SCI and the assessment of any associated factors.

RESULTS

Between January 2011 and August 2017, a total of 243 patients (mean aneurysm diameter, 65.2 ± 15.3 mm; mean age, 72.4 ± 7.5 years; 73% male) were treated with F-EVAR or B-EVAR. Asymptomatic patients were treated in 73% of the cases (177/243, in contrast to 27% urgent), and 52% (126/243) were treated for thoracoabdominal aortic aneurysm (in contrast to 48% for pararenal abdominal aortic aneurysm). F-EVAR (mean number of fenestrations, 3.3/case) and B-EVAR (mean number of branches, 3.7/case) were undertaken in 67% (164/243) and 33% (79/243), respectively. The total incidence of SCI was 17.7% [43/243; paraplegia in 4% (10/243) and paraparesis in 13.7% (33/243)]. Most of the patients with SCI presented with immediate postoperative symptoms (72% [31/43]). A spinal drain was preoperatively placed in 53% (130/243) and was associated with the prevention of SCI (SCI with spinal drainage, 12% [16/130]; SCI without spinal drainage, 24% [27/113]; P = .018). The 30-day mortality rate was 9% (21/243). After multiple logistic regression analysis, SCI was associated with preoperative renal function (SCI with preoperative glomerular filtration rate <60 mL/min/1.73 m²: odds ratio [OR], 2.43; 95% confidence interval [CI], 1.18-4.99; P = .016) and the number of vertebral segments covered (SCI with higher position of proximal stent in terms of vertebra: OR, 1.2; 95% CI, 1.1-1.3; P = .000). A similar outcome was derived when the height of the proximal end of the stent graft was replaced by the total length of aortic coverage (SCI with preoperative glomerular filtration rate <60 mL/min/1.73 m²: OR, 2.36 [95% CI, 1.11-5.00; P = .025]; SCI with longer length of aortic coverage: OR, 1.01 [95% CI, 1.003-1.009; P = .000]).

CONCLUSIONS

The majority of SCI incidence after F-EVAR or B-EVAR of complex aortic aneurysms is manifested immediately postoperatively. The use of preoperative spinal drainage may prevent SCI. Patients with GRF <60 mL/min/1.73 m² and with longer aortic stent graft coverage are at higher risk of SCI.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.

Combinatorial techniques for enhancing neuroprotection: hypothermia and alkalinization

Brain and spinal cord (CNS) trauma typically kill a number of neurons, but even more neurons are killed by secondary causes triggered by the initial trauma. Thus, a minor insult may rapidly cause the death of a vastly larger number of neurons and complete paralysis. The best mechanism for reducing the extent of neurological deficits is to minimize the number of neurons killed by post-trauma sequelae. Neuroprotection techniques take many diverse forms with a breadth too great for a short review. Therefore, this review focuses on the neuroprotection provided by hypothermia and a number of other neuroprotective techniques, when administered singly or in combination, because it is generally found that combinations of applications lead to significantly better neuroprotection than is achieved by any one alone. The combinatorial approach to neuroprotection holds great promise for enhancing the degree of neuroprotection following trauma, leading to maximum maintenance of neurological function.

The effects of systemic hypothermia on a murine model of thoracic aortic ischemia reperfusion

INTRODUCTION

Hypothermia is widely used to mediate ischemia-reperfusion injury associated with repair of the thoracoabdominal aorta. Experiments were designed in a murine model of thoracic aortic ischemia-reperfusion (TAR) to evaluate the effect of moderate systemic hypothermia on neurologic function, spinal cord morphology, and indices of inflammation in critical organs.

METHODS

C57BL/6 mice were subjected to TAR under hypothermic (34 degrees C) or normothermic (38 degrees C) conditions, followed by 24 or 48 hours of normothermic reperfusion. Neurologic functions were assessed during reperfusion. Spinal cords were examined at 24 and 48 hours after reperfusion, and the degree of injury qualified by counting the number of viable motor neurons within the anterior horns. Keratinocyte chemokine, interleukin-6, and myeloperoxidase levels were measured from lung, liver, and kidney at 24 and 48 hours.

RESULTS

Normothermic TAR resulted in a dense neurologic deficit in all mice throughout the reperfusion period. Mice subjected to TAR under hypothermic conditions had transient, mild neurologic deficit during the initial periods of reperfusion. Between 24 and 48 hours, delayed paralysis developed in half of these mice, whereas the other half remained neurologically intact. Spinal cord histology showed a graded degree of injury that correlated with neurologic function. There was no correlation between markers of inflammation in various organs and neurologic outcomes following TAR.

CONCLUSION

Systemic moderate hypothermia was protective against immediate paralysis after TAR in all cases and was associated with delayed paralysis in 50% of mice. This study suggests that delayed-onset paralysis may be the result of a local insult, rather than a systemic inflammatory event, precipitating spinal cord injury.

Advances in imaging of the spinal cord vascular supply and its relationship with paraplegia after aortic interventions. A review

INTRODUCTION

Preoperative knowledge of the spinal cord (SC) vasculature could be useful for stratifying and decreasing the risk of perioperative paraplegia after thoracic and thoraco-abdominal aortic surgery. Recent advances in magnetic resonance (MR) and computed tomography (CT) angiography and post-processing techniques have improved this knowledge.

METHODS

A search of MEDLINE/Pubmed and SCOPUS databases identified 1414 pertinent abstracts; 123 full-length manuscripts were screened to identify relevant studies with acceptable design and patient numbers. Forty-three were selected.

RESULTS

SC circulation was studied in 1196 patients to detect the great radicular artery: 522 by MR-angiography and 674 by CT angiography. Detection rates were 67-100% (mean 80.8%) with MR-angiography being 18-100% (mean 72%) with CT angiography. The side and level of the great radicular artery were consistent between the methods. Several authors tried to use the imaging results to guide clinical management.

CONCLUSIONS

Non-invasive imaging of the SC blood supply allows preoperative definition of the vasculature in many, but not all, cases. The impact of these findings on clinical management is potentially beneficial but still uncertain. Further improvements in image acquisition and post-processing techniques are needed. Future studies need to be large enough to compensate for inter-individual variability in SC vasculature in health and disease; however, even a partial reduction of paraplegia rate offers a formidable motivation for further research in this area.

Endovascular repair in the thoracic and abdominal aorta: no increased risk of spinal cord ischemia when both territories are treated

PURPOSE

To evaluate the morbidity associated with thoracic and abdominal aortic repair using endovascular exclusion alone or combined endovascular and open repair.

METHODS

Between January 1998 and February 2007, 49 patients (36 men; mean age 70 years) underwent treatment for thoracic and abdominal aorta disease with descending thoracic aortic (DTA) stent-graft and abdominal aortic repair. Thirty-nine patients with coexisting thoracic and abdominal pathologies were classified with multilevel aortic disease (MLAD), whereas 10 patients presented with thoracoabdominal aneurysm. Patients were separated into 3 groups: 1: thoracic stent-grafts and open abdominal repair (n = 18), group 2: thoracic and abdominal stent-grafts (n = 21), and group 3: thoracic stent-grafts with visceral artery debranching (n = 10). Prior carotid-subclavian bypass was performed in 3 (6%) patients with a dominant left vertebral artery.

RESULTS

Stent-graft deployment was technically successful in all cases. Eight (16%) patients underwent emergent thoracic stent-graft placement. In 9 (18%) patients, the left subclavian artery was covered. No incidence of spinal cord ischemia was observed. The 30-day mortality was 4%, and overall mortality was 6% over a mean 33-month follow-up. The endoleak rate was 6% (1 type I, 1 type II, and 1 type III).

CONCLUSION

Conventional or endovascular abdominal open repair in combination with DTA stent-grafting is feasible and a safe alternative to traditional open repair. Management of MLAD did not show increased incidence of spinal cord ischemia and was associated with fewer complications and deaths than simultaneous or staged open thoracic and abdominal repairs.

Thoracic and Thoracoabdominal Aneurysm Repair: Is Reimplantation of Spinal Cord Arteries a Waste of Time?

BACKGROUND

The impact of different strategies for management of intercostal and lumbar arteries during repair of thoracic and thoracoabdominal aortic aneurysms (TAA/A) on the prevention of paraplegia remains poorly understood.

METHODS

One hundred consecutive patients with intraoperative monitoring of motor evoked potentials (MEP) and somatosensory evoked potentials (SSEP) during TAA/A repair involving serial segmental artery sacrifice (October 2002 to December 2004) were reviewed.

RESULTS

Operative mortality was 6%. The median intensive care unit stay was 2.5 days (IQ range: 1-4 days), and the median hospital stay 10.0 days (IQ range: 8-17 days). Potentials remained unchanged during the course of serial segmental artery sacrifice, or could be returned to baseline levels by anesthetic and blood pressure manipulation, in 99 of 100 cases. An average of 8.0 +/- 2.6 segmental artery pairs were sacrificed overall, with an average of 4.5 +/- 2.1 segmental pairs sacrificed between T7 and L1, where the artery of Adamkiewicz is presumed to arise. Postoperative paraplegia occurred in 2 patients. In 1, immediate paraplegia was precipitated by an intraoperative dissection, resulting in 6 hours of lower body ischemia. A second ambulatory patient had severe paraparesis albeit normal cerebral function after resuscitation from a respiratory arrest.

CONCLUSIONS

With monitoring of MEP and SSEP, sacrifice--without reimplantation--of as many as 15 intercostal and lumbar arteries during TAA/A repair is safe, resulting in acceptably low rates of immediate and delayed paraplegia. This experience suggests that routine surgical implantation of segmental vessels is not indicated, and that, with evolving understanding of spinal cord perfusion, endovascular repair of the entire thoracic aorta should ultimately be possible without spinal cord injury.

Contemporary results of open surgical repair of descending thoracic aortic aneurysms

Considerable progress has been made in the refinement of operative strategies to repair descending thoracic aortic aneurysms (TAA). While no single strategy has totally eliminated the postoperative morbidities of renovisceral and spinal cord ischemic complications, contemporary reports from centers of excellence detail admirable rates of overall risk in the 5-10% range. Balancing these risks represents a clinical dilemma for the aortic surgeon and a thoughtful, logical risk analysis of the individual patient presentation is clearly warranted before TAA repair. In this article, we review surgical approaches to TAA and adjunctive methods, examine the reports from centers of excellence, and elucidate the challenges yet to be overcome in the management of patients with aneurysms of the descending thoracic aorta.

Immunosuppressants: neuroprotection and promoting neurological recovery following peripheral nerve and spinal cord lesions

No clinical techniques induce restoration of neurological losses following spinal cord trauma. Peripheral nerve damage also leads to permanent neurological deficits, but neurological recovery can be relatively good, especially if the ends of a transected nerve are anastomosed soon after the injury. The time until recovery generally depends on the distance the axons must regenerate to their targets. Neurological recovery following the destruction of a length of a peripheral nerve requires a graft to bridge the gap that is permissive to, and promotes, axon regeneration. But neurological recovery is slow and limited, especially for gaps longer than 1.5 cm, even using autologous peripheral nerve grafts. Without a reliable means of bridging long nerve gaps, such injuries commonly result in amputations. Promoting extensive neurological recovery requires techniques that simultaneously provide protection to injured neurons and increase the numbers of neurons that extend axons, while inducing more rapid and extensive axon regeneration across long nerve gaps. Although conduits filled with various materials enhance axon regeneration across short nerve gaps, pure sensory nerve graft remains the gold standard for use across long nerve gaps, even though they lead to only limited neurological recovery. Consistent results demonstrate that several immunosuppressive agents enhance the number of axons and the rate at which they regenerate. This review examines the roles played by immunosuppressants, especially FK506, with primary focus on its role as a neuroprotectant and neurotrophic agent, and its potential clinical use to promote improved neurological recovery following peripheral nerve and spinal cord injuries.

Neuroprotective effects of FK-506, l-carnitine and azathioprine on spinal cord ischemia-reperfusion injury

OBJECTIVE

In our experimental study, we aimed to test the effect of FK506, azathioprine and L-carnitine on protection of spinal cord injury due to ischemia-reperfusion.

METHODS

Twenty-seven Sprague-Dawley male rats were randomly divided into five groups. They were subjected to spinal cord ischemia by clamping the abdominal aorta for 45 min. Thirty minutes before the aortic clamping, group I received 0.5 mg/kg FK506, group II received 100 mg/kg L-carnitine, group III received 4 mg/kg azathioprine, the fourth group was the control group and received only normal saline injection intravenously and the last group was the sham group. Neurological status was scored by using the Tarlov scoring system. Sections of the lumbar cord were harvested for histopathological grades (1-4), having regard to percentage of the apoptotic cells.

RESULTS

Hind-limb motor function had recovered normally 48 h after the operation in all rats which received FK506, azathioprine and L-carnitine prophylactically. In contrast, all rats in the control group had deteriorated to paraplegia by 48 h after the operation (P<0.05). Histopathologic sections in the involved spinal cord segment showed that a greater number of motor neuron cells were preserved and there were less apoptotic cells in the rats that received FK506, azathioprine and L-carnitine than those in control group.

CONCLUSIONS

These results suggest that prophylactic use of FK506, azathioprine and L-carnitine protects motor neuron cells from ischemic spinal cord injury.

Regional hypothermia with epidural cooling for prevention of spinal cord ischemic complications after thoracoabdominal aortic surgery

Multiple operative adjuncts have been developed and clinically applied to reduce the incidence of spinal cord ischemic complications (SCI) after thoracoabdominal aneurysm (TAA) repair. Hypothermia is known to reduce oxygen requirements in central nervous tissue and has been successfully applied in the arena of central cardioaortic surgery. Based on our experimental and clinical results, we have employed regional hypothermia by epidural cooling to ameliorate SCI during TAA repair in over 300 patients. This review describes the results obtained in our experience using an approach to TAA repair whereupon the spinal cord is protected during surgery by regional hypothermia via epidural cooling.

Protective effect of prostaglandin E1 against ischemia of spinal cord during aortic cross clamping

PURPOSE

The purpose of this study was to investigate whether or not 5-minute segmental intraaortic perfusion of prostaglandin E1 (PGE1) in the preischemic period has a protective effect against spinal cord ischemia during aortic cross clamping.

METHODS

The rabbits were divided into two groups. In group A (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. In group B (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution containing PGE1 of 100 ng/kg/min at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. After the aorta was declamped, the experimental animals recovered from the anesthesia. Twenty-four and 48 hours after the operation, the hind limb function was estimated with Tarlov's grade. Then, the animals were killed for pathologic study.

RESULTS

The systolic arterial pressures measured at the left common carotid artery through the experiment were not significantly different between the two groups. The perfusion of the aortic segment between the proximal and distal clamp was nonpulsatile. The perfusion pressures of the aortic segments at 5 minutes after aortic cross clamping were 29 +/- 6 mm Hg and 33 +/- 6 mm Hg in groups A and B, respectively. No significant differences were seen between the two groups. In group A, the hind limb functions evaluated with Tarlov's grade after 24 hours and 48 hours were 0 to 3 (1.5 +/- 1.4) and 0 to 3 (1.3 +/- 1.4), respectively. In group B, these were 3 to 4 (3.5 +/- 0.5) and 3 to 4 (3.7 +/- 0.5), respectively. A significant difference was seen between the two groups (P <.05). In the ventral horn of the L5, L6, and L7 segments, large motor neurons that seemed viable were more preserved in group B than in group A.

CONCLUSION

Segmental intraaortic perfusion of PGE1 in the preischemic period reduced neurologic damage of spinal cord ischemia.

Thoracoabdominal aneurysm repair: results with 337 operations performed over a 15-year interval

OBJECTIVE

To review perioperative results and late survival after thoracoabdominal aneurysm repair (TAA), in particular to assess the impact over time of epidural cooling (EC) on spinal cord ischemic complications (SCI).

SUMMARY BACKGROUND DATA

A variety of operative approaches and protective adjuncts have been used in TAA to minimize the major complications of perioperative death and SCI. There is no consensus with respect to the optimal approach.

METHODS

From January 1987 to November 2001, 337 consecutive TAA repairs were performed by a single surgeon. Clinical features included prior aortic grafts in 97 (28.8%) and emergent operation in 82 (24.6%), including rupture in 46 (13.6%) and dissection in 63 (19%). Operative management consisted of a clamp/sew technique with adjuncts in 93%. EC (since July 1993) to prevent SCI was used in 194 (57.6%) repairs. Variables associated with the end points of operative mortality and postoperative SCI were assessed with the Fisher exact test and logistic regression; late survival was estimated with the Kaplan-Meier method.

RESULTS

Operative mortality was 8.3% and was associated with nonelective operation, intraoperative hypotension, total transfusion requirement, and the postoperative complications of paraplegia, renal failure, and pulmonary insufficiency. Postoperative renal failure and transfusion requirement were independent correlates of mortality. SCI of any severity occurred in 38 of 334 (11.4%) operative survivors, with 22/38 (6.6% of cohort) sustaining total paraplegia. EC reduced the risk of SCI in patients with types I-III TAA (10.6% vs. 19.8%, =.04). Independent correlates of SCI over the entire study interval included types I/II TAA, rupture, cross-clamp duration, sacrifice of T9-L1 intercostal vessels, and intraoperative hypotension. Late survival rates at 2 and 5 years were 81.2 +/- 3% and 67.2 +/- 5%.

CONCLUSIONS

EC has decreased the risk of SCI after TAA repair. Decreasing the substantial proportion (nearly 25%) of patients requiring nonelective operation will improve results. Late survival is equal to that after routine AAA repair, indicating that the considerable resource expenditure required for TAA repair is worthwhile.

Spinal cord arteriography: a safe adjunct before descending thoracic or thoracoabdominal aortic aneurysmectomy

OBJECTIVE

Spinal cord arteriography (SCA) often has been considered difficult, hazardous, and unreliable. In this report, we question these assumptions.

PATIENTS

From August 1985 to June 2000, a total of 480 patients underwent 487 SCA procedures during diagnostic examination for 498 aneurysms, which included 159 that involved the descending thoracic aorta and 339 that involved the thoracoabdominal aorta. The underlying cause was degenerative disease in 288 cases, chronic dissection in 132 cases, and other causes in 78 cases.

RESULTS

Major procedure-related complications occurred in six patients (1.2%) and included spinal cord complications in two patients, renal complications in two patients, and stroke in two patients. Puncture-site complications occurred in three patients (0.6%). Rupture of the aneurysm occurred within 3 days after SCA in two patients (0.4%). Two deaths (0.4%) were directly imputable to SCA. In 476 patients (97.7%), SCA was devoid of major complications. The Adamkiewicz's artery was successfully located in 419 patients (86.0%) and arose from a left intercostal or lumbar artery in 323 patients (77.1%) and from between T8 and L1 levels in 361 patients (86.2%). On the basis of the extent of identification of spinal cord vasculature, the procedure was considered as a complete success in 321 patients (65.9%), as a partial success in 112 patients (23.0%), and as a failure in 54 patients (11.1%). Although the failure rates were comparable, the complete success rate was significantly higher in patients with degenerative rather than dissecting aneurysms (P <.001) and in patients with limited aneurysms (ie, types 1, 2, and 3 versus type 4 descending thoracic aneurysms, P <.05; and types 3 and 4 versus types 1 and 2 thoracoabdominal aneurysms, P <.001).

CONCLUSION

SCA is a safe adjunct that warrants more widespread use in the management of descending thoracic or thoracoabdominal aortic aneurysms.

Morphological changes of the anterior spinal artery during aortic cross-clamping and effect of prostaglandin E1 with perfusion

This investigation was designed to evaluate the morphological changes of anterior spinal artery (ASA) and its reaction to prostaglandinE1 (PGE1) during aortic cross-clamping. ASA during 30 min cross-clamping was observed with charge-coupled device (CCD) and ASA diameter (ASAD) was measured. Group A: Infrarenal aorta was cross-clamped. Group B: Infrarenal aorta was cross-clamped and aorta above the bifurcation was snared. The aortic segment between clamp and snare was perfused with blood. Group C: PGE1 of 100 ng/kg/min was added to perfusate of Group B. The aortic segmental pressures in group B and C were about 30% of the proximal systolic arterial pressure and were significantly higher than distal pressure of group A. After cross-clamping, ASAD decreased about 80% of before cross-clamping in group A. By segmental perfusion of which pressure was about 30% of proximal systolic arterial pressure, ASAD remained almost 90% in group B. By administration of PGE1, ASAD was significantly increased in group C. The changes of ASAD were significantly different between group A and C, and between group B and C.

Epidural cooling for spinal cord protection during thoracoabdominal aneurysm repair: A five-year experience

PURPOSE

We developed and applied a method for providing regional spinal cord hypothermia with epidural cooling (EC) during thoracoabdominal aneurysm (TAA) repair. Preliminary results indicated significant reduction in spinal cord ischemic complications (SCI), compared with historical controls, and a 5-year experience with EC was reviewed.

METHODS

From July 1993 to September 1998, 170 patients with thoracic aneurysms (n = 14; 8.2%) or TAAs (types I and II, n = 83 [49%]; type III, n = 66 [39%]; type IV, n = 7 [4.1%]) were treated with EC. An earlier aneurysm resection was noted in 44% of patients, an emergent operation was noted in 20% of patients, and an aortic dissection was noted in 16% of patients. The EC was successful (mean cerebrospinal fluid [CSF] temperature at cross-clamp, 26.4 +/- 3 degrees C) in 97% of cases, with all 170 patients included in an intention-to-treat analysis. The operation was performed with a clamp/sew technique (98% patients) and selective (T(9) to L(1) region) reimplantation of intercostal vessels. Clinical and EC variables were examined for association with operative mortality and SCI by means of the Fischer exact test, and those variables with a P value less than.1 were included in multivariate logistic regression analysis.

RESULTS

The operative mortality rate was 9.5% and was weakly associated (P =.07) with SCI; postoperative cardiac complications (odds ratio [OR], 35. 3; 95% CI, 5.3 to 233; P <.001) and renal failure (OR, 32.2; 95% CI, 6.6 to 157; P <.001) were the only independent predictors of postoperative death. SCI of any severity occurred in 7% of cases (type I/II, 10 of 83 [12%]; all other types, 2 of 87 [2.3%]), versus a predicted (Acher model) incidence of 18.5% for this cohort (P =. 003). Half the deficits were minor, with good functional recovery, and devastating paraplegia occurred in three patients (2.0%). Independent correlates of SCI included types I and II TAA (OR, 8.0; 95% CI, 1.4 to 46.3; P =.021), nonelective operation (OR, 8.3, 95% CI, 1.8 to 37.7; P =.006), oversewn T(9) to L(2) intercostal vessels (OR, 6.1; 95% CI, 1.3 to 28.8; P =.023), and postoperative renal failure (OR, 23.6; 95% CI, 4.4 to 126; P <.001). These same clinical variables of nonelective operations (OR, 7.7; 95% CI, 1.4 to 41.4; P =.017), oversewn T(9) to L(2) intercostal arteries (OR, 9.7; 95% CI, 1.5 to 61.2; P =.016), and postoperative renal failure (OR, 20.8; 95% CI, 3.0 to 142.1; P =.002) were independent predictors of SCI in the subgroup analysis of high-risk patients, ie, patients with type I/II TAA.

CONCLUSION

EC has been effective in reducing immediate, devastating, total paraplegia after TAA repair. A strategy that combines the neuroprotective effect of regional cord hypothermia, avoiding the sacrifice of potential spinal cord blood supply, and postoperative adjuncts (eg, avoidance of hypotension, CSF drainage) appears necessary to minimize SCI after TAA repair.

Emergency repair of thoracoabdominal aortic aneurysms with immediate presentation

OBJECTIVE

The objective of this report was the study of the clinical outcome of emergently repaired thoracoabdominal aortic aneurysms (TAAAs).

METHODS

We retrospectively reviewed our experience with TAAA repairs from 1990 to 1998. During this interval, 110 TAAA procedures were performed, 33 (30%) of which were for immediate presentations. The chi(2) test and regression analysis were used for the analysis of mortality, paraplegia, and renal failure (hemodialysis) rates and of factors that predict these complications, respectively.

RESULTS

There were no significant differences between the elective and immediate presentations with respect to the use of adjunctive procedures (lumbar drain, hypothermia, and bypass grafting). The overall mortality rate was 13%. There were no statistically significant differences between the 30-day mortality rates or the complication rates in elective versus immediate presentations. Subgroup analysis results showed a significantly higher in-hospital mortality rate in type II TAAA with immediate presentation and free rupture presentation as compared with the overall mortality rate (50% vs 13%, P <.05, and 67% vs 13%, P <.01, respectively). Multiple regression analysis results identified the use of bypass grafting (atrial-femoral or cardiopulmonary) and lumbar drain and shorter bypass grafting time as significant predictors of decreased overall mortality (P <.05). The mortality rates were not significantly different among aneurysm types and were not significantly decreased with the use of hypothermia. Paraplegia (5%) and renal failure (9%) rates were not predicted with aneurysm type, immediate versus elective presentation, or the adjunctive use of hypothermia, lumbar drain, or bypass grafting.

CONCLUSION

The emergency repair of TAAA with immediate presentation can be performed with mortality and morbidity rates that approach those of elective presentations, except in the setting of free rupture or symptomatic type II TAAA. Adjunctive circulatory management techniques and lumbar drains may reduce mortality in TAAA repair.

Thoracoabdominal aortic aneurysm repair: how I do it

There remains no consensus on the operative management of Thoracoabdominal aortic aneurysm (TAA). Our approach emphasizes operative expediency and simplicity (without circulatory assist techniques), avoiding anticoagulation and systemic hypothermia. The technique involves a fundamental clamp/sew method with specific adjuncts directed against the principle complications: epidural cooling (introduced in 1993) for spinal cord protection, regional renal hypothermia, and in-line mesenteric shunting to minimize visceral ischemia. In a cohort of over 200 TAA patients (50% Types I & II) treated during the past decade perioperative mortality has been 8% and paraparesis/paraplegia occured in 7%. These figures are halved for patients treated in elective circumstances.