Deep vein thrombosis and heterotopic ossification in spinal cord injury: a 3 year experience at the Swiss Paraplegic Centre Nottwil.

Study Design: Retrospective review of patient data.

Objectives: (i) To determine the incidence and time of deep vein thrombosis (DVT) under low molecular weight heparin (LMWH) prophylaxis in spinal cord injury (SCI), (ii) to determine the incidence and time of heterotopic ossification (HO) and (iii) to assess a possible aetiologic relationship in the pathogenesis of DVT and HO.

Setting: Swiss Paraplegic Centre, Nottwil.

Methods: We analyzed the incidence of DVT and HO in 1209 SCI patients (275 first rehabilitations) at the Swiss Paraplegic Centre Nottwil from 1998 to 2000. Clinical files and laboratory data were scrutinised for particularities preceding DVT and HO.

Results: The incidence of DVT was 6.55% for first rehabilitation compared to only 1.59% in all patients hospitalised. DVT was complicated by pulmonary embolism (PE) in 1.45% and 0.47% respectively. Incidence of HO was 8% for first rehabilitation and 1.82% for all patients hospitalised. In first rehabilitation patients the peak for DVT occurred around day 30 contrary to HO with a peak around day 120. In single patients HO was identified by MRI as a rapidly progressing process. Laboratory profiles were inflammatory in both HO and DVT. Increased physical activity preceding HO was observed in four patients. In two patients acute HO was complicated by ipsilateral DVT.

Conclusion: Prophylaxis with LMWH and elastic stockings significantly reduces the frequency of DVT during first rehabilitation in SCI. DVT and HO are both associated with laboratory parameters of non-infectious inflammation. The later onset of HO coinciding with ongoing mobilisation, argues for a different pathogenetic mechanism. Acute HO of the hip region appears to favour ipsilateral DVT by well known thrombogenic mechanisms.