The Incidence of Pelvic DVT Following Combined Anterior/Posterior Reconstruction for Adult Spinal Deformity: A Prospective Cohort Study Using Magnetic Resonance Venography

Background: Conventional screening for Deep Venous Thrombosis (DVT) following combined anterior/posterior spinal reconstructions cannot adequately detect pelvic DVT. Magnetic Resonance Venography (MRV) is the most effective means of detecting pelvic DVT but is rarely used in spine patients. The purpose of this study was to prospectively define the incidence of DVT following combined anterior/posterior spinal fusions using MRV as an adjunct to screening.

Methods: Prospective cohort study of 46 consecutive adult patients (mean age 52.4+/-9.6 yrs) undergoing combined anterior/posterior spine fusions. Exclusion criteria included a history of DVT or pulmonary embolus (PE), known coagulopathies, or a contraindication to MRI. Demographic, intraoperative, and postoperative data were recorded. All patients received only pneumatic compression foot pumps (Plexipulse®) for DVT prophylaxis. MRV and bilateral lower extremity Doppler ultrasounds were obtained postoperatively (mean 7.6 and 7.9 days, respectively).

Results: Total incidence of postoperative DVT was 10.9% (5 patients). Pelvic DVT incidence was 4.3% (2 patients) and lower extremity DVT was 6.5% (3 patients). All DVTs were immediately treated with therapeutic anticoagulation. PE developed in two patients less than 48 hours after positive Doppler studies (4.3%), both in conjunction with lower extremity DVT and were subsequently treated with IVC filter placement. Right-sided thoracoabdominal approaches were associated with increased risk of developing DVT (p=0.02), and in particular, lower extremity DVT (p=0.012).

Conclusion: We report an increased incidence of pelvic and lower extremity DVT and PE following combined anterior/posterior spinal fusions. A significant proportion of DVTs in these patients arise in the pelvis. Right-sided thoracoabdominal approaches may represent a significant risk factors for the development of postoperative DVT in this patient population. We recommend postoperative screening with Doppler ultrasound and MRV in these patients, with treatment initiated only after a positive study.