Abstract
Introduction
Patients undergoing spine surgery by the posterior approach are subjected to excessive and constant pressure on the operative site, because decubitus adopted (dorsal) in most procedures, including lying on his back on the injury held recently. The increased pressure on the wound after surgery may lead to tissue ischemia and this fact may explain why patients operated on by posterior approach have higher rates of pain and infection postoperatively. This prospective, controlled study was designed to demonstrate the excess pressure on the muscle of the wound in patients submitted to surgery in the spine by the posterior approach when they assume supine position.
Patients and Methods
A total of 22 patients undergoing major surgery in the thoracic and lumbar regions had a fiber optic catheter (Codman ICP Monitoring System, Jonhson and Jonhson) inserted in to the body (right or left) of the paraspinal muscles. The catheter was inserted 3 cm lateral to the incision and 5 cm deep. The pressure was measured and recorded hourly obeying the order of dorsal decubitus, right and left lateral decubitus for 24 hours postoperatively with the patient at bed rest. After this period the catheter was removed.
Results
Patients had a mean age of 55.9 ± 4.2 years (11 men and 11 women); height of 167.8 ± 2 cm; weight and BMI (body mass index) was 73.0 ± 2 (kg), and 25.3 ± 0.8, respectively. The average abdominal circumference was 93.7 ± 2.7 cm. ANOVA showed a significant difference in mean pressure (24 hours) from the supine position (24.7 ± 2.0 mm Hg) with left or right lateral decubitus (4.92 ± 2.3 mm Hg and 4.77 ± 2.83 mm Hg). There was no significant correlation between weights, sex, BMI, and waist circumference with the pressure of decubitus adopted by the patient, or with the side that the catheter was inserted.
Conclusion
The supine position adopted in the postoperative period of major spine surgery through the posterior approach can be a factor implicated in postoperative complications. The pressure difference is significant enough to exceed capillary pressure.