Side-to-side arteriovenous fistula at the elbow with perforating vein ligation.

OBJECTIVE: We postulated that ligation of a consistent perforating venous branch at the elbow would improve distention and flow in the superficial veins about the elbow. This would also lesson the likelihood of arterial steal enabling a favorable outcome following a brachial artery medial antecubital or cephalic vein arterio-venous fistula (AVF). METHODS: Pressure measurements were made from the radial artery after side-to-side brachial artery antecubital or cephalic vein AVF in 20 patients. Clamping of the perforating vein increased radial artery pressure significantly indicating that a considerable amount of flow from the side-to-side AVF was diverted into the deep system and away from the accessible superficial veins. Encouraged by this finding, we studied the outcome of brachial cephalic or brachial antecubital AVF with ligation of the deep branch in 134 patients who were not candidates for radio-cephalic AVF. The end point of the study was successful hemodialysis using the fistula. RESULTS: Of the 134 patients treated, 24 died, and 11 were lost to follow-up and were censored from analysis of fistula performance at that time point. The primary fistula success rate was 89.7% +/- 2.66% and 83.7% +/- 3.5% at 1 and 2 years by life table analysis. No patient developed significant arterial steal or venous hypertension. CONCLUSION: We recommend this simple one-stage procedure for patients requiring hemodialysis whose cephalic vein at the wrist is unsuitable.

Trends in the in-hospital stroke rate following carotid endarterectomy in California and Maryland.

OBJECTIVE: We examined the outcome of carotid endarterectomy (CEA) in the state of Maryland during the last decade to identify any trends in the incidence of in-hospital stroke and mortality and compared these results with the outcome of the operation throughout the state of California as a control population. METHOD: We performed a retrospective analysis of 10 years (1994 to 2003) of the Maryland and 5 years (1999 to 2003) of the California hospital discharge databases. The following patients were included in the analysis: (1) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 38.12 (endarterectomy of the vessels of the head and neck other than intracranial vessels) in the primary coding position but not in any secondary position, or (2) the diagnosis code 433.00 to 433.91 (occlusion/stenosis, precerebral artery), or (3) the diagnosis-related group (DRG) 5 (extracranial vascular procedure). Symptomatic patients were identified by history of previous stroke (ICD-9 codes 342 or 438), transient ischemic attack (435 or 781.4), or amaurosis fugax (362.34 or 368.12). In-hospital strokes were identified by ICD-9 codes 997.0, 997.00, 997.01, and 997.09. Low-, moderate-, and high-volume surgeons were defined as performing <15, 15 to 74 and >or=75 CEAs annually. Hospital volumes were similarly classified as low for those performing 100 annually. RESULTS: In the Maryland data, 23,237 CEA cases were identified with 169 in-hospital strokes over 10 years (0.73%), whereas the 51,331 California CEAs had 232 in-hospital strokes over 5 years (0.45%). The stroke rate in Maryland was 2.12% in 1994, 1.47% in 1995, and 0.29% to 0.65% from 1996 to 2003. The decrease in strokes was more pronounced among symptomatic patients, where the rate was 3.82% in 1994, 4.44% in 1995, and 0.90% to 2.29% from 1996 to 2003. A similar decrease was identified in the asymptomatic patient population but was less pronounced: 1.64% in 1994, 0.81% in 1995, and 0.15% to 0.44% from 1996 to 2003. The low recent stroke rates were confirmed by the California data (0.44% to 0.48% from 1999 to 2003). Changes in the death rate for CEA during this time frame have not been as pronounced, from 0.33% to 0.58% for Maryland and 0.78% to 0.91% for California. CONCLUSIONS: A dramatic decrease in the in-hospital stroke rates in Maryland occurred around 1995. The stroke rates in Maryland in the past 5 years are similar to those in California during the same period. An analysis of data from the two states shows that the in-hospital stroke rate now for carotid endarterectomy is approximately 0.54%.

The mitochondrial K-ATP channel opener, diazoxide, prevents ischemia-reperfusion injury in the rabbit spinal cord.

Paraplegia resulting from ischemia is a catastrophic complication of thoracoabdominal aortic surgery. The current study was designed to investigate the effects of diazoxide (DZ) on mitochondrial structure, neurological function, DNA damage-repair, and apoptosis in spinal cord ischemia-reperfusion injury. Rabbits were subjected to 30 minutes of spinal cord ischemia and reperfusion (1 hour) with or without diazoxide (n = 6 in each group) by clamping and releasing the infrarenal aorta. The neurological functional score was significantly improved in the DZ-treated ischemia-reperfusion injury group. Electron microscopic studies demonstrated that mitochondrial damage in the spinal cord after injury was significantly reduced by DZ. Mitochondrial superoxide and hydrogen peroxide levels were also markedly decreased in the DZ-treated injury group compared with the untreated group. DZ decreased levels of the oxidative DNA damage product 8-oxoG and increased levels of the DNA repair enzyme OGG-1. Furthermore, DZ inhibited apoptosis via caspase-dependent and -independent pathways. These studies indicate for the first time that the mitochondrial K-ATP channel opener diazoxide improves neurological function after spinal cord ischemia and reperfusion by diminishing levels of reactive oxygen species, decreasing DNA oxidative damage, and inhibiting caspase-dependent and -independent apoptotic pathways while preserving mitochondrial structure.

Preoperative and intraoperative determinants of incisional bulge following retroperitoneal aortic repair.

Although the left flank retroperitoneal incision is a useful approach for many patients undergoing major aortic reconstruction for aneurysmal and occlusive disease, it has been associated with weakening of the flank muscles, resulting in bulges varying from slight asymmetry to huge hernias. The purpose of this study was to determine if the incidence of this complication correlated with identifiable preoperative or intraoperative factors. Fifty consecutive patients undergoing aortic reconstruction via the retroperitoneal approach were followed for 1 year postoperatively for evidence of disfiguring bulges. Bulges were scored as follows: normal/mild, <1-inch protrusion; moderate, protrusion 1-2 inches; severe, protrusion >2 inches and/or pain or true herniation. Preoperatively, patients were administered a questionnaire to elicit demographic and comorbidity data. Fifty-six percent of patients developed a bulge at 1 year. In 43% of these, the bulge was deemed mild and in 54% moderate. One patient developed a severe bulge. Among preoperative comorbidities, no statistically significant correlations were found on bivariate analysis. However, likelihood ratios for bulge development of 5.5 for renal disease and 3.1 for cancer were demonstrated. Conversely, peripheral vascular disease had a likelihood ratio of 0.21 for bulge formation and emphysema, 0.28. On logistic analysis, incision >15 cm and body mass index (BMI) >23 mg/kg(2) were found to correlate strongly with bulge formation (p=0.003, odds ratio=9.1, and p=0.018, odds ratio=16.9, respectively). Together, these yielded a pseudo r (2) of 0.32. BMI >23 mg/kg(2 )was found to yield the greatest explanatory power. These same two variables were found to correlate with severity of bulge: p=0.02 for incision>5 cm and p=0.006 for BMI >23. Of note, gender, age, and extension of the incision into the interspace were not significant on logistic analysis. Preoperatively, surgeons should warn obese patients and those requiring large incisions for extensive disease of their increased risk for poor healing. Intraoperatively, surgeons should aim to minimize incision length.

Twenty-year experience with acute distal thoracic aortic dissections.

BACKGROUND: There are few large studies in the literature that document the clinical outcome of an acute dissection of the distal thoracic aorta (ADDA), particularly since the advent of percutaneous techniques for therapeutic and prophylactic treatment of complications of ADDA. The goal of this study was to evaluate the outcome of ADDA with respect to medical, surgical, and percutaneous treatment over a 20-year period, and to use this information to estimate the benefit that future prophylactic therapy may yield. METHODS: The hospital records of all patients admitted with ADDA during the period of the study were reviewed retrospectively. RESULTS: There were 119 patients who fit the criteria of ADDA. Medical management was performed in 92 patients, with an overall mortality in this group of 13% (12/92 patients). Major morbidity occurred in 34 of the 83 surviving patients managed nonoperatively. Percutaneous interventions consisting of aortic fenestration and branch vessel stenting in 5 patients had a mortality rate of 40% and was only effective in the treatment of isolated renal artery malperfusion. Twenty-two patients underwent aortic surgery for complications or risk of impending rupture. Postoperative mortality was 18% (4/22 patients). Significant risk factors for death were rupture, acute renal failure, mesenteric ischemia, and age >70. No patient who had surgical fenestration required reoperation on the tailored segment. On the basis of clinical outcomes, we estimate that a maximum of 37% of patients could benefit acutely from prophylactic treatment of ADDA with aortic stent grafts, and an additional 13% could benefit chronically from such prophylactic treatment. CONCLUSIONS: ADDA remains a challenging clinical problem with many failures of medical, surgical, and percutaneous therapy. Surgery remains an effective therapeutic option in the treatment of complications of acute dissection of the distal thoracic aorta, and surgical aortic fenestration is a durable treatment for malperfusion. A minority of patients may benefit from prophylactic treatment of ADDA with thoracic stent grafts.

The organ center of the United Network for Organ Sharing and twenty years of organ sharing in the United States.

The increasing size of the transplant waiting list and the increasing use of expanded criteria donors places a premium on efficient use of recovered organs. Maximal organ utilization often necessitates organ sharing between transplant organizations. Optimal organ sharing requires rapid, integrated communication of donor information combined with expedited organ transportation. For more than 20 years, the United Network for Organ Sharing's Organ Center has fulfilled this task for the United States transplant community. This overview details a brief history of United States organ sharing and the role played by the Organ Center. The current scope and modes of Organ Center operations are detailed.

Preoperative selective intercostal angiography in patients undergoing thoracoabdominal aneurysm repair.

OBJECTIVE: This study was designed to test the hypothesis that detection of the location of the major artery supplying the spinal cord, that is, the artery of Adamkiewicz or the great radicular artery (GRA), with angiography would help prevent paraplegia. Knowing which intercostal artery provides this important branch would enable prompt, focused revascularization. METHOD: The surgical outcome in 131 patients with Crawford extent 1 and 2 degenerative aneurysms and 69 patients with descending thoracic aortic dissection was correlated with findings on selective intercostal arteriograms. Angiographic maneuvers were done with care, and the procedures were aborted if there was loose or "shaggy" mural thrombus, significant tortuosity, or difficulty entering each dissection channel. No attempts were made to find major contributions proximal to T6. Subarachnoid drains were placed in all patients, and all but five patients underwent distal aortic perfusion with controlled cooling to 32 degrees F. Five patients underwent cold circulatory arrest, enabling replacement of the distal aortic arch. We defined paraplegia simply as the inability to walk at hospital discharge, paraparesis as impaired ambulation, and both as having spinal cord dysfunction (SCD). RESULTS: A GRA was found in 65 (43%)of the 151 patients studied. Of the 65 patients with the GRA identified, SCD developed in 3 (4.6%) patients. Thirteen of 135 (9.6%) patients in whom the GRA was not identified, either because they were not studied or were studied and the GRA was not found, developed SCD (P =.35) However, when the GRA was identified, SCD occurred only in the group with aortic dissection. None of the 45 patients with degenerative aneurysms with the GRA identified had SCD, compared with 9 of 55 (16%) patients studied but without a GRA found (P =.01). CONCLUSION: The approach with selective intercostal angiography did not improve overall results. One third of our patients were not studied, and they fared as well as patients who were studied and the GRA was localized (not studied, 4 of 49, 8% with SCD; GRA localized, 3 of 65, 5% with SCD; P =.8). However, when the GRA was found, SCD occurred only in patients with aortic dissection. The studies confirmed the concept that the existence of mural thrombus in degenerative aneurysms results in the occlusion of many intercostal arteries, leaving those remaining patent to supply rich vascular watersheds through acquired collateral channels. As a result, in the group of patients with degenerative aneurysms, the identification of the critical intercostal artery allows focused reimplantation with uniform success. This is not the case in patients with aortic dissection. In those patients, most intercostal vessels remain patent, such that the insertion of one pair is insufficient to supply the paravertebral plexus and the spinal cord. Finally, failure to identify the GRA angiographically with our methods does not provide assurance that the GRA does not exist. Therefore negative findings did not provide license to ligate all intercostal arteries.

Preliminary studies of the application of near infrared spectroscopy in the diagnosis of deep vein thrombosis.

A feasibility study for diagnosing deep vein thrombosis utilizing near-infrared continuous wave spectroscopy was performed, as a real-time, non-invasive, and inexpensive method. The probe contains two light sources and two detectors with optical filters that monitor reflected light at wavelengths 760 and 850 nm to measure the changes in the amount of deoxyhemoglobin and oxyhemoglobin, respectively. These changes and the blood volume changes are recorded while the subject performs a series of light leg exercises. The test protocol is designed to determine the muscle tissue blood volume capacity, rate of blood filling (venous valve functionality test), and efficiency to promote one-directional venous flow from the leg to heart. The subject pool consists of the patients with leg deep vein thrombosis (DVT) diagnosed by the Johns Hopkins Hospital Vascular Surgery Department and of normal subjects as the control. Abnormal venous systems showed distinct characteristics: high blood volume in the leg; high rate of blood filling while the subject stands upright; and the inability to decrease the blood volume during the muscle contraction. The NIR device proved to be an inexpensive, effective, and portable device that can detect DVT in the leg in real-time.

Sensitivity of routine intensive care unit surveillance for detecting myocardial ischemia.

OBJECTIVE: To assess the effectiveness of routine intensive care unit surveillance compared with frequent 12-lead electrocardiogram monitoring for detecting electrocardiogram evidence suggestive of prolonged myocardial ischemia in vascular surgery patients. DESIGN: Prospective cohort trial. SETTING: Intensive care unit. PARTICIPANTS: We studied 149 patients undergoing elective infrainguinal or aortic vascular surgery who were admitted to the intensive care unit postoperatively. INTERVENTIONS: Patients were simultaneously monitored with a 10-electrode/12-lead electrocardiogram obtained every 2 mins (criterion standard) and routine intensive care unit surveillance that included standard monitoring (five-electrode/two-lead electrocardiogram with ST segment trends and routine 12-lead electrocardiogram) and clinical assessment for detecting myocardial ischemia. The results of the criterion standard were not available to the caregivers. MEASUREMENTS AND MAIN RESULTS: We measured the ability of routine intensive care unit surveillance to detect the first 20 mins of electrocardiogram evidence suggestive of myocardial ischemia, defined as ST segment depression or elevation of >/=1 mm in two consecutive leads, during the first postoperative day. Seventeen patients (11%) had electrocardiogram evidence suggestive of prolonged myocardial ischemia, the majority of which occurred in leads V2-V4. The sensitivity of routine intensive care unit surveillance for detecting the first episode of electrocardiogram evidence suggestive of prolonged myocardial ischemia in a patient was 12% (95% confidence interval, 7-17%), and the specificity was 98% (95% confidence interval, 95-100%) with a positive predictive value of 40% (95% confidence interval, 32-48%), a negative predictive value of 90% (95% confidence interval, 85-94%), a positive likelihood ratio of 6, and a negative likelihood ratio of 1. The sensitivity of routine intensive care unit surveillance for detecting all episodes was 3% (95% confidence interval, 2-3%) and the specificity 99% (95% confidence interval, 99-100%) per 20-min monitoring interval, with a positive predictive value of 17% (95% confidence interval, 16-18%), negative predictive value of 95% (95% confidence interval, 95-96%), positive likelihood ratio of 3, and negative likelihood ratio of 1. CONCLUSIONS: Routine intensive care unit surveillance has low sensitivity for detecting electrocardiogram evidence suggestive of prolonged myocardial ischemia compared with frequent 12-lead electrocardiograms. Because detecting electrocardiogram evidence suggestive of prolonged postoperative myocardial ischemia is important, physicians should consider alternative strategies to detect myocardial ischemia.

Use of a human polymerized hemoglobin solution as an adjunct to acute normovolemic hemodilution during complex abdominal aortic reconstruction.

Oxygen-carrying hemoglobin (Hb) solutions are under intense investigation as an alternative to allogeneic red cell transfusion during surgery, with or without acute normovolemic hemodilution. We present a case in which an investigational Hb solution was used as an adjunct to acute normovolemic hemodilution, and as a replacement for surgical blood loss in a patient undergoing complex aortic reconstruction with a large blood loss.

DNA damage and repair system in spinal cord ischemia.

BACKGROUND AND PURPOSE: Spinal cord ischemia-reperfusion injury may be initiated by a number of mediators, including reactive oxygen species. Recent studies have shown that human MutY homologue (hMYH), human 8-oxo-7,8-dihydrodeoxyguanine (8-oxoG) glycosylase (hOGG1), and human MutS homologue 2 (hMSH2) are important DNA mismatch repair genes. We hypothesized that ischemia-reperfusion injury in spinal cord causes DNA damage manifested by 8-oxoG production and activates the DNA repair system involving hMYH, hOGG1, and hMSH2. METHODS: Spinal cords of rabbits were removed at 1, 3, 6, 24, and 48 hours after 30 minutes of infrarenal aortic occlusion. DNA damage was determined with 8-oxoG staining. The expression and localization of DNA repair enzymes, such as hMYH, hOGG1, and hMSH2, were studied with Western blot analysis and immunohistochemical staining. The level of apoptosis was determined with TUNEL study. Activation of caspase-3, an enzyme induced by cellular injury that leads to apoptosis by degrading cellular structural proteins, was also studied. RESULTS: DNA damage monitored with 8-oxoG level was significantly present from 1 hour to 6 hours after reperfusion in gray matter neurons of ischemic spinal cord. The levels of hMYH, hOGG1, and hMSH2 were markedly increased in gray matter neurons at 6 hours after reperfusion. Caspase-3 was also induced at 6 hours to 24 hours after reperfusion in ischemic spinal cord. However, the peak level of TUNEL reactivity was found at 48 hours after reperfusion in spinal cord neurons. CONCLUSION: This study has shown, for the first time, the rapid expression of DNA damage-repair processes associated with spinal cord ischemia and subsequent reperfusion.

The distribution of carotid endarterectomy procedures among surgeons and hospitals in New York state: is regionalization of specialized vascular care occurring?

INTRODUCTION: In a published analysis of all carotid endarterectomies (CEAs) performed in New York state from 1990 to 1995, perioperative mortality rate was inversely correlated with surgeon and hospital CEA volume, was significantly higher when CEAs were performed by surgeons who performed less than five CEAs annually, and was significantly lower in hospitals where surgeons performed more than 100 CEAs annually. The purpose of this study was to determine whether this information has influenced practice patterns in New York state. METHODS: The database of the Center for Medical Consumers was queried to determine the volume distribution among surgeons and hospitals of all CEAs performed in New York state in 1999 and 2000. RESULTS: During 1999, 695 surgeons in 169 hospitals performed 9458 CEAs (mean, 13.6 per surgeon). Three hundred fifty-three surgeons (51%) performed less than five CEAs, and 180 (26%) performed only one CEA during the year. Only 41 surgeons (6%) performed more than 50 CEAs. Likewise, in only 28 of the hospitals (17%) were more than 100 CEAs performed during 1999, whereas in 73 of the hospitals (43%) 20 or less CEAs were carried out during the year. During 2000, 684 surgeons performed 8196 CEAs in 165 hospitals. Three hundred fifty-three (52%) performed less than five CEAs, and 229 (33%) performed only one CEA during the year. Only 33 surgeons (5%) performed more than 50 CEAs during 2000. In only 26 hospitals (16%) were more than 100 CEAs performed during 2000, whereas in 71 hospitals (43%) 20 or less CEAs were carried out. CONCLUSION: It appears that published compelling evidence that operator and institutional volume influence outcome has not influenced referral patterns or led to a regionalization of CEA care in New York state. Robust educational programs directed to patients and referring physicians appear indicated.

Cardiac troponin I predicts short-term mortality in vascular surgery patients.

BACKGROUND: Cardiac troponin I (cTnI) is a highly sensitive and specific marker for myocardial injury that predicts outcomes in patients with acute coronary syndromes. Cardiovascular complications are the leading cause of morbidity and mortality in patients who have undergone vascular surgery. However, postoperative surveillance with cardiac enzymes is not routinely performed in these patients. We evaluated the association between postoperative cTnI levels and 6-month mortality and perioperative myocardial infarction (MI) after vascular surgery. METHODS AND RESULTS: Two hundred twenty-nine patients having aortic or infrainguinal vascular surgery or lower extremity amputation were included in this study. Blood samples were analyzed for cTnI immediately after surgery and the mornings of postoperative days 1, 2, and 3. An elevated cTnI was defined as serum concentrations >1.5 ng/mL in any of the 4 samples. Twenty-eight patients (12%) had postoperative cTnI >1.5 ng/mL, which was associated with a 6-fold increased risk of 6-month mortality (adjusted OR, 5.9; 95% CI, 1.6 to 22.4) and a 27-fold increased risk of MI (OR, 27.1; 95% CI, 5.2 to 142.7). Furthermore, we observed a dose-response relation between cTnI concentration and mortality. Patients with cTnI >3.0 ng/mL had a significantly greater risk of death compared with patients with levels < or =0.35 ng/mL (OR, 4.9; 95% CI, 1.3 to 19.0). CONCLUSIONS: Routine postoperative surveillance for cTnI is useful for identifying patients who have undergone vascular surgery who have an increased risk for short-term mortality and perioperative MI. Further research is needed to determine whether intervention in these patients can improve outcome.

Durability of thoracoabdominal aortic aneurysm repair in patients with connective tissue disorders.

OBJECTIVE: Thoracoabdominal aortic aneurysm (TAAA) repair is a durable procedure performed with reasonable perioperative mortality and morbidity in patients with atherosclerotic aortic disease. However, the long-term outcome and durability of TAAA repair performed in patients with a connective tissue disorder (CTD) is not well known. METHODS: The records of 257 patients who underwent TAAA repair at the Johns Hopkins Hospital between January 1992 and December 2001 were reviewed. Survival analysis was performed with Kaplan-Meier analysis, and subgroups were compared with the log-rank test. Multivariable analysis was performed with the Cox proportional hazards model and logistic regression. RESULTS: Patients with CTD (n = 31) were seen earlier (mean age, 48.6 +/- 2.9 years) than patients without CTD (mean age, 69.1 +/- 0.6 years; P <.0001, Mann-Whitney U test) and had a greater incidence rate of aortic dissection (52% versus 19%; P <.0001, chi(2) test) and extent I or II aneurysm (77% versus 64%; P =.04). The perioperative (30-day) mortality rate was 6.5% in patients with CTD, which was similar to the rest of the cohort (P =.39, Fisher exact test). The incidence rate of paraparesis/paraplegia was 12.9%/6.5% in patients with CTD, and CTD was the only factor predictive of paraparesis (P =.03; odds ratio, 9.3; logistic regression). The cumulative survival rate among the entire cohort was 53.4% +/- 4.4% at 5 years (Kaplan-Meier), and no difference was seen among patients with or without CTD (P =.16, log-rank test) or among different Crawford extents (P =.29). Of the two late (>6 months) deaths in patients with CTD, none were from aortic rupture or dissection, compared with two of 31 late deaths in patients without CTD. Multivariable analysis confirmed that postoperative renal failure (P =.03) predicted mortality but neither CTD (P =.93), nor Crawford extent (P =.21, Cox regression) predicted mortality. Among survivors, no mean difference was found in largest aortic diameter on follow-up imaging in patients with or without CTD (4.7 +/- 0.3 cm versus 4.4 +/- 0.3 cm; P =.47, Mann-Whitney U test). The cumulative graft patency rate, representing long-term graft stability and with death, rupture, dissection, or recurrent aneurysm as endpoints, was 47.5% +/- 4.6% at 5 years (Kaplan-Meier) and was similar in patients with or without CTD (P =.10, log-rank test). CONCLUSION: TAAA repair appears to be a durable operation, with a reasonable 5-year patient survival rate and a low risk of postoperative paraplegia or additional aortic events. Patients with CTD can expect their outcome, including long-term survival and aortic stability, to be similar to patients without CTD.

Subdural hematoma after thoracoabdominal aortic aneurysm repair: an underreported complication of spinal fluid drainage?

OBJECTIVE: Cerebrospinal fluid (CSF) drainage is a commonly used adjunct to thoracoabdominal aortic aneurysm (TAAA) repair that improves perioperative spinal cord perfusion and thereby decreases the incidence of paraplegia. To date, little data exist on possible complications, such as subdural hematoma caused by stretching and tearing of dural veins, should CSF drainage be excessive. We reviewed our experience with patients in whom postoperative subdural hematomas were detected. METHODS: The records of 230 patients who underwent TAAA repair at the Johns Hopkins Hospital between January 1992 and February 2001 were reviewed. RESULTS: Eight patients had subdural hematomas (3.5%). The four men and four women had a mean age of 60.6 years; two of these patients had a connective tissue disorder. All patients had lumbar drains placed before surgery, including one patient who underwent an emergency operation for rupture. Drains were set to allow drainage for CSF pressure greater than 5 cm H(2)O in all but one patient set for 10 cm H(2)O; spinal cooling was not performed in any patient. All drains were removed on the third postoperative day. In patients in whom subdural hematomas developed, the mean amount of CSF removed after surgery was 690 +/- 79 mL, which was significantly greater than the amount drained from patients in whom subdural hematomas did not develop (359 +/- 24 mL; P =.0013, Mann-Whitney U test). Six patients had postoperative subdural hematomas detected during hospitalization (mean postoperative day, 9.3; range, 2 to 16), and two patients were seen in delayed fashion after discharge from the hospital at 1.5 and 5 months. Four patients died of the subdural hematoma (50%); only one of these patients had neurosurgical intervention. All four survivors responded to neurosurgical intervention and are neurologically healthy. Two patients, both of whom were seen in delayed fashion, needed a lumbar blood patch. Multivariate logistic regression identified the volume of CSF drained as the only variable predictive of occurrence of subdural hematoma (P =.01). CONCLUSION: Subdural hematoma is an unusual and potentially catastrophic complication after TAAA repair. Prompt recognition and neurosurgical intervention is necessary for survival and recovery after acute presentation. Epidural placement of a blood patch is recommended if a chronic subdural hematoma is detected. Care should be taken to ensure that excessive CSF is not drained perioperatively, and higher (10 cm H(2)O) lumbar drain popoff pressures may be necessary together with meticulous monitoring of patient position and neurologic status.

A contemporary assessment of carotid body tumor surgery.

Carotid body tumor resection remains a surgical challenge traditionally associated with a 15-30% incidence of cranial nerve injury. The authors reviewed their experience with carotid body tumor surgery to determine whether contemporary awareness of carotid body tumors is leading to earlier detection and operation, resulting in a lower incidence of postoperative cranial nerve injury. Twenty-seven carotid body tumors were resected in 25 patients between 1990 and 2000. No patient died and no patient had postoperative baroreflex failure syndrome. There was 1 stroke (4%) in a patient who required ligation of the internal carotid artery. There were 9 cranial nerve injuries (33%), most commonly to the vagus or hypoglossal nerves, which was not significantly different from the rate of cranial nerve injury (44%) in the 9 patients operated upon between 1984 and 1989 (p=0.37, Fisher's exact test). Multivariate analysis demonstrated that tumor size was the only significant factor predicting cranial nerve injury (p=0.045, logistic regression). Since carotid body tumors with large size or higher Shamblin grades had predictably high operative blood loss and rates of postoperative cranial nerve injury, a high index of suspicion and aggressive surgical management may lead to earlier detection and operation on smaller tumors, ultimately reducing the risk of nerve injury. Nevertheless, carotid body tumor surgery appears to be relatively free of mortality and major morbidity in contemporary practice.