[Spinal anesthesia: a protective factor in thromboembolic disease. A retrospective cohort study of 484 arthroplasties].

Objectives: To compare general and spinal anesthesia in the context of thromboembolic disease after orthopedic surgery in patients receiving prophylactic therapy with low molecular weight heparins.

Patients And Method: Of the 484 arthroplasties studied retrospectively, 209 involved total hip prostheses, 111 partial hip prostheses and 164 total knee prostheses. Spinal anesthesia (epidural or subarachnoid) was provided in 328 cases and general anesthesia in 156. Thromboembolic disease was diagnosed if the patient presented a compatible clinical picture or if there was confirmation by Doppler ultrasonography and/or venography for deep venous thrombosis or by scintigraphy for pulmonary embolism. Related factors studied were age; weight; prior fractures of the lower extremity; a history of thromboembolism, diabetes, high blood pressure or heart disease; and medication.

Results: Twenty-one patients experienced thromboembolic complications, 12 after general anesthesia and 9 after spinal anesthesia, the incidence in the latter being significantly lower (p < 0.01, odds ratio 3.23, 95% CI). Multivariant analysis also showed a significant increase in thromboembolic disease (p = 0.05) among patients over 70 years of age (odds ratio 2.67, 95% CI).

Conclusions: Spinal anesthesia provides some protection against thromboembolic disease in arthroplasty. Age is a risk factor.