The effect of carotid endarterectomy on cerebral blood flow and cognitive function.

BACKGROUND: The effect of carotid endarterectomy on cognitive function is not fully understood. This study aims to characterize changes in cerebral blood flow after carotid endarterectomy and to determine if patients with improvement in cerebral blood flow have improved cognitive function after endarterectomy. METHODS: Cerebral blood flow was measured preoperatively and 1 month postoperatively using phase contrast magnetic resonance angiography. Preoperative flow impairment was defined as ipsilateral flow at least 20% less than contralateral flow. Improvement in flow was defined as an absolute increase of at least 0.10 in flow ratio from pre- to postoperative assessments. Patients underwent cognitive testing preoperatively and at 1, 6, and 12 months postoperatively. RESULTS: Twenty-four patients with unilateral carotid stenosis were enrolled from 3 sites. Preoperative internal carotid artery (ICA) and middle cerebral artery (MCA) flow impairment was observed in 50% and 22% of patients, respectively. Patients with preoperative flow impairment had an average of 0.25 and 0.16 absolute improvement in flow ratio in the ICA and MCA vessels, respectively; this was statistically significant for patients with baseline ICA flow impairment (P < .01). One hundred percent of patients with improvement in MCA flow had a significant improvement in attention compared to 56% of patients without MCA flow improvement (P = .06). Clinically significant improvements in all 4 cognitive domains were observed at 1 year (P < .01). CONCLUSIONS: Patients with baseline impairment of MCA blood flow were more likely to experience improvement in flow after revascularization. Improvement in MCA blood flow was associated with greater cognitive improvement in attention and executive functioning.

Ventral versus dorsal decompression for cervical spondylotic myelopathy: surgeons' assessment of eligibility for randomization in a proposed randomized controlled trial: results of a survey of the Cervical Spine Research Society.

STUDY DESIGN: Surgeons attending a Cervical Spine Research Society (CSRS) meeting were surveyed about the surgical approach to cervical spondylotic myelopathy (CSM). OBJECTIVE: To elicit spine surgeons' opinions on the suitability of a panel of test cases for randomization in a proposed randomized controlled trial (RCT) of ventral versus dorsal decompression for CSM. SUMMARY OF BACKGROUND DATA: The optimal surgical decompression strategy for CSM has not been defined. Specific eligibility criteria should be defined before a RCT is initiated. METHODS: Twenty actual cases with images were prepared. Surgeons supplied demographic information, preferred surgical approach, and eligibility for randomization for 10 cases. RESULTS: A total of 91 of 239 (38%) surgeons completed the survey. Of 900 case-strategy responses, 51% recommended ventral surgery, 38% dorsal surgery, and 11% a combined approach. Both overall C2-C7 kyphosis >5 degrees and a segmental kyphotic deformity were inversely correlated with eligibility for randomization (P < 0.001 for both). Using these 2 criteria plus age over 85 years, ossification of the posterior longitudinal ligament, and congenital canal stenosis as additional exclusion criteria, 12 of 20 survey cases were considered potentially eligible for randomization. Orthopedic and neurologic surgeons were similar in determining a case's eligibility for randomization. CONCLUSIONS: These results measure surgeons' opinions on the suitability of cases for randomization and help to define entry and exclusion criteria for a RCT comparing ventral to dorsal strategies. Over 50% of CSM cases from a general spinal practice might be eligible for randomization.