Researchers push ‘defined’ role for DVT treatment after spine surgery

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minimally invasive surgeryA review of bleeding and thrombotic complication rates in elective spine surgery patients has suggested that further study is needed to “define the role” of routine deep vein thrombosis (DVT) chemoprophylaxis following elective spine surgery. This is the conclusion of Sean Pirkle (Department of Orthopaedic Surgery and Rehabilitation Medicine, University of Chicago Medical Center, Chicago, USA) and colleagues who carried out the research, published in the Global Spine Journal.

Through the study, Pirkle and colleagues sought to examine the utilisation rate of postoperative DVT prophylaxis and compare the incidence and severity of bleeding and thrombotic complications in elective spine surgery patients.

Many surgeons, they note, rely on a patient’s risk profile to advise the administration of chemical prophylaxis in the postoperative setting to limit the risk of venous thromboembolism. The study team found that historically, the incidence of postoperative epidural haematoma has been reported in 0.3% of cases, compared with values ranging from 0.8% to 15.5% for DVT following elective spine surgery.

Presently, Pirkle and colleagues suggest, there are no universally agreed recommendations for anticoagulant administration in spine surgery patients, although some small studies have investigated outcomes related to anticoagulant prophylaxis following spine surgery, documenting a low risk of bleeding complications, including epidural haematomas.

Because of the low incidence of severe bleeding and thrombotic complications, the study team writes, a large data sample is required to assess if one type of complication occurs more frequently than the other.

Pirkle and colleagues conducted a retrospective review of the Humana Insurance subset of the Pearl Diver national database—which contains around 25 million patient records. The patient population was identified for six different spinal procedures: anterior cervical fusion, anterior lumbar fusion, posterior cervical fusion, posterior cervical laminectomy/laminoplasty, posterior lumbar fusion and posterior lumbar laminectomy. Patients matching the inclusion criteria were required to have active records in the database for at least six months following the index procedure.

Two groups of patients were analysed, composed of patients who had not received chemoprophylaxis and patients who had received chemoprophylaxis within five days of procedure. Complications were limited in these patients from the same day of intervention until three months post-operation. The research team compared rates of bleeding complications (epidural haematoma, haematoma, seroma) to rates of thrombotic complications (DVT, PE). Proportions of patients who experienced bleeding and thrombotic complications, wound washout and PE, ICU admission associated with wound washout and PE, and mortality after ICU admission were compared using chi-square tests an alpha level of .05.

To better define a cohort of spine patients who may optimally benefit from any change in contemporary practices, patients not administered chemoprophylaxis were stratified by the presence of various comorbidities and perioperative factors associated with increased bleeding and thrombotic risks. Variables assessed in this analysis included patient age and gender, atrial fibrillation, cancer, chronic obstructive pulmonary disease, congestive heart failure, hypertension, number of levels treated, obesity, oral contraceptive use, prior history of bleeds, prior history of thrombosis and tobacco use.

The study team identified 119,888 patients who fulfilled the inclusion criteria. Of these, the majority of patients (118,720) were not administered DVT chemoprophylaxis within the first five days of their spine procedure. Within this group, they found that overall rates of bleeding and thrombotic complications differed significantly (1.96% vs. 2.45%; p<0.001). Additionally, Pirkle and colleagues note, the rate of patients who underwent surgical intervention for a wound washout procedure was 0.62% compared to 1.05% for a diagnosis of pulmonary embolism (p<0.001). This trend was consistent and observed for subanalyses of all six spinal procedures, the study group found.

In contrast, 1,168 patients were placed on anticoagulant therapy following surgical spine procedures, representing 0.97% of all patients who had undergone spinal procedures in the study. Patients in this group, the study team found, experienced much higher rates of overall thrombotic complications compared to bleeding (10.36% vs. 2.65% p<0.001). However, due to the small sample size represented by this group, no further analysis was conducted.

Discussing the findings, Pirkle and colleagues write that unlike other surgery, there is no standard of care in regard to DVT chemical prophylaxis after routine elective spine surgery. “Studies have suggested caution with the use of chemoprophylaxis while also acknowledging the dearth of quality literature studying this subject,” the study team notes. “As a result, the current practice of chemoprophylaxis after spine surgery is largely driven by dogma and not by quality data.”

The study team further observed that within the group who did not undergo chemoprophylaxis, patients experienced significantly greater postoperative thrombotic complications when compared with bleeding complications at all levels of severity. “Depending on severity,” they write “this resulted in anywhere from 1.17 to 1.31 times greater likelihood of developing any thrombotic complication. These risks were magnified when comparing what we defined as more severe complications, increasing to 1.53 to 1.98 times greater risk of thrombotic complications.” Futhermore, they add, this patient population experienced a 2.92 to 6.45 times greater risk of ICU admission for thrombotic complications when compared to bleeding complications.

When broken down by comorbidity, Pirkle and colleagues note that several groups experienced the greatest increase in thrombotic complications. These include patients with a diagnosis of atrial fibrillation, cancer, or prior history of thrombotic complication. They note that patients with these medical histories, “would potentially be the ideal candidates for DVT prophylaxis following elective spine surgery.”

They conclude: “In the present study’s population, which did not receive DVT chemoprophylaxis, the risks of thrombotic complications were significantly greater than bleeding complications for patients specifically with atrial fibrillation, cancer, or a prior history of thrombotic complications.” However, the study team warns that for those not matching these criteria, the risks of DVT prophylaxis, may not outweigh the benefits.

The data strongly suggest that additional study is needed to determine optimal thromboprophylaxis strategies in elective spine surgery patients, Pirkle and colleagues add. “Such a study would be of great importance in fully defining the role of routine DVT chemoprophylaxis after elective spine surgery,” they end.


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