Gary G. Nicholas

Role of magnetic resonance imaging in the diagnosis of osteomyelitis in diabetic foot infections

PURPOSE The role of magnetic resonance imaging (MRI) in the diagnosis of osteomyelitis in foot infections in diabetics was investigated. The accuracy, sensitivity, and specificity of MRI, plain radiography, and nuclear scanning were determined for diagnosing osteomyelitis, and a cost comparison was made. METHODS Twenty-seven patients with diabetic foot infections were studied prospectively. All patients underwent MRI and plain radiography. Twenty-two patients had technetium bone scans, and 19 patients had Indium scans. Nineteen patients had all four tests performed. Patients with obvious gangrene or a fetid foot were excluded. RESULTS The diagnosis of osteomyelitis was established by pathologic specimen (n = 18), bone culture (n = 3), or successful response to medical management (n = 6). Osteomyelitis was confirmed in nine of the pathologic specimens. The diagnostic sensitivity, specificity, and accuracy for MRI was 88%, 100%, and 95%, respectively, for plain radiography it was 22%, 94%, and 70%, respectively, for technetium bone scanning it was 50%, 50%, and 50%, respectively, and for Indium leukocyte scanning it was 33%, 69%, and 58%, respectively. The data were analyzed statistically with the two-tailed Fishers exact test. MRI was the only test that was statistically significant (p < 0.01). CONCLUSIONS MRI appeared to be the single best test for the diagnosis of osteomyelitis associated with diabetic foot infections. It had a better diagnostic accuracy than conventional modalities and appeared to be more cost-effective than the frequently used Indium scan.

Death and adverse cardiac events after carotid endarterectomy

PURPOSE This study evaluated operative mortality rate and adverse cardiac events after carotid endarterectomy. Efficacy of preoperative cardiac evaluation was studied and stroke mortality rate was determined. METHODS This was a retrospective review of 562 patients undergoing carotid endarterectomy at a 740-bed community hospital. Data were analyzed with chi 2 analysis, logistic regression analysis, and Goldman criteria for cardiac risk. RESULTS The mortality rate was 1.6% (nine patients). There were 10 myocardial infarctions (1.8%). Six of these (1.1%) were fatal. The Goldman Index allowed us to classify 530 patients in a low-risk group (Goldman classes I and II, operative mortality rate = 1.1%) and 32 patients in a high-risk group (Goldman classes III and IV, mortality rate = 9.4%). Independent risk variables were identified for myocardial infarction and overall operative death. These variables were then used to develop a probability model for prediction of operative death and adverse cardiac events. The stroke rate in the 562 patients was 0.7% (four patients). For the 345 patients with symptoms, the stroke rate was 0.6% (two patients); for the 217 symptom-free patients, it was 0.9% (two patients). The combined stroke mortality rate was 2.3%. For patients with symptoms, it was 2.9%; for symptom-free patients, it was 1.4%. CONCLUSIONS Independent clinical variables can help determine patients at increased risk for perioperative myocardial infarction or operative death. Patients in Goldman classes III and IV are at increased risk for adverse events. Carotid surgery can be performed safely in our medical community.

Carotid Artery Stenosis: Preoperative Noninvasive Evaluation in a Community Hospital.

PURPOSE The purpose of this study was to determine whether noninvasive evaluation with duplex ultrasonography and magnetic resonance angiography of patients with carotid artery stenosis can replace contrast angiography at our institution. METHODS This study consisted of a retrospective chart review of 40 patients (74 carotid arteries) in combination with a blinded reanalysis of original data. Contrast angiography was compared with duplex ultrasonography and magnetic resonance angiography. The overall diagnostic accuracy of duplex ultrasonography and magnetic resonance angiography was determined individually and concordantly in patients being evaluated for carotid artery stenosis. RESULTS The overall sensitivity of duplex ultrasonography was 88.5%, and the specificity was 91.7% (Spearman correlation coefficient = 0.8456; p < 0.001). For magnetic resonance angiography the sensitivity was 92.3%, and the specificity was 97.9% (Spearman correlation coefficient = 0.9086; p < 0.001). In the presence of concordance, the noninvasive studies exhibited a sensitivity of 100%, (correlation coefficient = 0.9661; kappa value = 0.9655). No occlusions or severe lesions were missed by both studies. In only one vessel (1.52%) was a false-positive concordance noted. CONCLUSIONS Carotid endarterectomy may be undertaken with a high degree of confidence that the operation will be appropriate if the noninvasive evaluations are concordant. In the absence of concordance of the noninvasive studies, contrast angiography should be considered.

Accessory nerve injury during carotid endarterectomy

Injury to the accessory nerve (cranial nerve XI) during carotid endarterectomy is rare; to date only three cases have been reported in the literature. Traction on the sternocleido-mastoid muscle was the proposed mechanism of injury in all three cases. Four cases of accessory nerve palsy occurred in 850 carotid endarterectomies performed between 1978 and 1986 at this institution, an incidence of 0.47%. All four patients had classic signs and symptoms of accessory nerve injury, which developed between 20 and 60 days after operation. The three most recent cases were examined specifically for accessory nerve injury in the immediate postoperative period and exhibited normal trapezius function. None had any other central nervous system dysfunction. Two of these patients regained full accessory nerve function and the most recent case is showing signs of reinnervation with conservative therapy. Isolated central nervous system and spontaneous accessory nerve palsies are exceptionally rare, and since any traction injury or transection should have been detected by postoperative examinations in three of four patients, we propose surgical scar formation as a mechanism of accessory nerve palsy after carotid endarterectomy. If such a palsy develops in the postoperative period, we recommend conservative therapy.

The cerebral hyperperfusion syndrome: diagnostic value of ocular pneumoplethysmography.

PURPOSE There were two purposes to our study. The first was to characterize the ocular hyperperfusion associated with carotid endarterectomy. The second was to relate ocular hyperperfusion to the clinical presentation of cerebral hyperperfusion syndrome. METHODS This was a retrospective chart review of 2331 patients who underwent carotid endarterectomy at our institution between June 1978 and May 1991. RESULTS Twelve of these carotid endarterectomies were associated with ocular hyperperfusion on the side of operation. Clinical evidence of cerebral hyperperfusion syndrome was observed in five of these 12 procedures. In these five patients there were two associated fatal intracerebral hemorrhages and one permanent coma. In the latter three patients the contralateral internal carotid arteries were totally occluded. CONCLUSION Ocular hyperperfusion, as documented with ocular pneumoplethysmography, is useful in alerting the physician to the potential for development of the cerebral hyperperfusion syndrome.

Asymptomatic Carotid Endarterectomy Patient and Surgeon Selection

BACKGROUND AND PURPOSE The applicability of prospective carotid endarterectomy protocols to the general population has been questioned. Outcomes for asymptomatic patients undergoing carotid endarterectomy were compared with the results of the Asymptomatic Carotid Atherosclerosis Study (ACAS) patients treated concurrently at our institution. METHODS Asymptomatic patients undergoing carotid endarterectomies (n = 277) from 1987 to 1993 (ACAS enrollment period) were reviewed. Primary end points were mortality, myocardial infarction, and stroke. Five subgroups were studied: (1) ACAS surgical patients; (2) ACAS-eligible patients not enrolled and ACAS surgeons; (3) ACAS-eligible patients not enrolled and non-ACAS surgeons; (4) ACAS-ineligible patients and ACAS surgeons; and (5) ACAS-ineligible patients and non-ACAS surgeons. RESULTS ACAS-eligible patients were younger (P = .014), had more severe carotid stenosis (P = .001), and had lower incidences of pulmonary (P = .015) and renal (P = .008) diseases compared with ineligible patients. Patient selection (ACAS eligibility) significantly improved outcomes for mortality (P = .014) and myocardial infarction (P = .006). Length of stay favored ACAS-eligible patients (P = .004). ACAS surgeons operated on more severely stenotic carotid lesions (P = .005) and on patients with a lower incidence of coronary artery disease (P = .007). There was no difference in outcomes between ACAS and non-ACAS surgeons. CONCLUSIONS Patient selection was a significant factor in determining outcome. With strict adherence to ACAS enrollment guidelines, the conclusions of ACAS appear applicable to patients seen at our institution with asymptomatic carotid stenosis.

Free-tissue transfers for limb salvage utilizing in situ saphenous vein bypass conduit as the inflow

Using vein grafts to bypass sclerotic and occluded arterial segments is a well-established technique in vascular surgery. For infrapopliteal bypass, autogenous veins have better patency rates than synthetic grafts. Although not resolved, in situ bypasses seem to be better than reversed bypasses, especially for “far away” segments. Although the etiology is not understood, it is a well-known clinical finding that sclerosis affects arteries more than the veins and, as a whole, is more advanced in lower extremities compared with the trunk and upper extremities. Our experience with eight patients in whom critical soft-tissue defects were covered with free-tissue transfers in severely compromised lower extremities utilizing the in situ saphenous vein bypass as the inflow is presented. Simultaneous bypass and free-tissue transfers were performed in seven and delayed free-tissue transfer was done in one. Follow-up ranged from 6 months to 3 years. To date, two patients underwent amputations. Five patients are able to maintain bipedal ambulation. One patient is wheelchair-bound with intact lower extremities. In well-selected patients, this procedure may offer an alternative treatment to amputation. However, because of the complexity of these combined procedures, we strongly urge careful patient selection.

Carotid endarterectomy outcomes research: reduced resource utilization using a clinical protocol.

BACKGROUND AND PURPOSE The purpose of this study was to examine the necessity of intensive care unit (ICU) utilization following carotid endarterectomy (CEA) and to identify patients who can be managed postoperatively on a vascular unit using a clinical protocol. METHODS Medical records of 50 patients admitted to the ICU following elective CEA were reviewed retrospectively for patient characteristics, morbidity, mortality, length of stay (LOS), and ICU intervention. Prospectively, the next 200 patients were routed to either a vascular unit or ICU, based on a clinical protocol. Endpoints were mortality, stroke, myocardial infarction, total hospital LOS, ICU LOS, and ICU intervention. RESULTS There were no significant differences in morbidity or mortality between patients admitted to the vascular unit and those admitted to the ICU. Of patients evaluated prospectively, 129 (63%) were admitted directly to the vascular unit. Of the 73 patients admitted to the ICU, 63% required direct intervention compared with only 54% of patients in the retrospective series (P=0.001). In addition, after institution of the protocol, ICU LOS decreased significantly from 1.4 to 0.6 days (P<0.001). The hospital cost savings using this protocol averaged

Infrainguinal Bypass in Patients with End-stage Renal Disease: Survival and Ambulation

1043 per patient. CONCLUSIONS A clinical protocol can select patients for admission to the ICU or the vascular unit following CEA without increase in morbidity or mortality. Selective use of the ICU conserved resources, decreased ICU LOS, and provided substantial cost savings.

Gastroesophageal tumor embolization to the popliteal arteries

The purpose of this study was to evaluate the outcomes of infrainguinal bypass surgery and ambulatory status in patients with end-stage renal disease (ESRD). Vascular registry data and the medical records of patients requiring infrainguinal bypass surgery from 1985 through 1995 were reviewed retrospectively. Patients with chronic limb-threatening ischemia requiring maintenance hemodialysis or peritoneal dialysis for ≥ 6 months were compared to a randomly selected group of patients under going foot salvage infrainguinal bypass in the absence of ESRD. Primary outcomes were mortality, amputation, and ambulatory status at 30 days and 1 year. Data were analyzed using Pearsons chi-square methods, Fishers Exact test, Mann-Whitney U, life table analyses, and Quality of Life-Class (QL-Class) ranking. There were 57 patients with ESRD who underwent 66 infrainguinal bypass proce dures. Mean age was 65.8 ±9.8 years (41-85 years). The 30-day operative mortality rate was 12.3% (7 patients). The cumulative survival at 1 year was 51.8% ±0.9%, and at 2 years it was 32.8% ± 1.3%. The cumulative limb loss was 29.7% ± 1.1% at 1 year and 36.7% ±2.6% at 2 years. In the comparison group, 46 patients without ESRD underwent 50 infrainguinal bypass procedures. The mean age of these patients was 72.3 ±9.1 years (36-90 years). The cumulative survival for the patients without ESRD was significantly higher (p < 0.001) both at 1 year (91.1% ±0.6%) and 2 years (88.8% ±0.8%). The cumulative limb loss for the comparison group was significantly lower (p < 0.001) at 1 year (4.1% ±0.4%) and at 2 years (6.3% ±0.5%). At both 30 days and 1 year, the QL- Class walking status rating was lower for the group with ESRD compared to patients without ESRD (p < 0.001). Patients with ESRD have a high mortality rate in the first 24 months after infrain guinal bypass grafting for foot salvage surgery compared with a similar group of patients without ESRD. Although foot salvage can be achieved in some survivors with ESRD, the ambulatory rate is low. These results support a very conservative approach when recom mending infrainguinal bypass grafting for foot salvage surgery for patients with ESRD.