To the best of our knowledge, this is the first study to conduct a cross-sectional analysis of preoperative DVT data of patients scheduled for elective surgery for degenerative musculoskeletal disorders. Our data showed that the preoperative prevalence of DVT in the patients with musculoskeletal degenerative disorders was 7.4%. In addition, our analysis revealed that the factors associated with preoperative DVT were advanced age, knee surgery, high ASA physical status, and malignancy.
According to the American College of Chest Physicians’ evidence-based clinical practice guideline (ACCP), TKA and THA themselves are risk factors of DVT [4]. In the present study, 6.1% of the patients scheduled for THA had DVT, even before the surgery. This proportion is consistent with those reported in previous studies (5.2–12.3%) [8–10]. Although DVT screening methods, either ultrasonography or computed tomography, differ among studies, previous studies reported the discrepancies in the frequency of preoperative DVT in TKA (2.6–11.7%) as well as THA [11–13]. The prevalence of preoperative DVT in TKA in the present study was 14.7%, which is higher than those in previous studies. Owing to issues on radiation exposure with CT [17], ultrasonography will probably be the main method used in screening for preoperative DVT. Furthermore, the advancements in ultrasonography technology could continuously increase the detection rate of preoperative DVT [18]. Meanwhile, the measurement of D-dimer levels has already been well established in the first screening for DVT [4]. Consistently, our data showed that the D-dimer levels were significantly higher in the patients with than in those without preoperative DVT. The cutoff D-dimer level in the first DVT screening was 1.0 µg/mL in the present study, although the ideal value has yet to be determined and is a topic for future research.
The multivariate analysis in the present study revealed that knee surgery with TKA or UKA is one of the factors associated with the preoperative DVT. Besides knee surgery, the other factors found to be associated with preoperative DVT in our analysis were advanced age, ASA physical status, and malignancy, which were consistent with the previously reported risk factors of postoperative VTE [3, 19]. In patients with knee osteoarthritis, restricted knee flexion and extension due to knee pain or limited joint range of motion may result in DVT prevalence in the veins of the lower extremities. In addition, Baker’s cyst, commonly associated with knee osteoarthritis, has been reported to compress the neurovascular bundle in the popliteal fossa [20]. Therefore, cysts around the knee joint that are associated with knee osteoarthritis may increase the frequency of DVT. In the future, the relationship between knee osteoarthritis severity and incidence of DVT should be examined.
According to the ACCP, the risk of VTE is considered moderate in spinal surgeries for malignant diseases but relatively low in elective surgeries for degenerative spinal disorders [4]. Recently, Winther et al. reported that the incidence of symptomatic VTE in elective surgeries for degenerative spinal disorders was 0.2% [14]. Meanwhile, Takahashi et al. retrospectively examined elective spinal surgeries in a group of patients who underwent the procedure to prevent VTE and in a group who did not [21]. They found that the incidence of symptomatic PTE was significantly lower in the preventive VTE group [21]. Therefore, although the frequency of elective surgeries for degenerative spinal disorders is low, preventing VTE is observed to be important, as well as performing TKA and THA. According to Liu et al., the incidence of preoperative DVT in patients with cervical spondylotic myelopathy scheduled for spinal surgery was 4%, which is similar to the results of this study [15]. Meanwhile, Yamasaki et al. found that the incidence of preoperative DVT in elective lumbar spine surgeries was 7.7% when the vertebral body fracture group was excluded [16], which is also similar to the lumbar surgery data from the present study. As the population ages, patients undergoing elective surgeries for degenerative spinal disorders will be older, their ASA physical status will be higher, and majority of them will have malignancies. Therefore, the risk of VTE incidence is also expected to continuously increase, making symptomatic VTE prevention in patients undergoing elective surgeries for degenerative spinal disorders even more important.
This study has several limitations. First, our data were retrospectively collected from a limited number of patients in a single institution. Second, a selection bias exists in this study because ultrasonography was added as a screening procedure in the patients with D-dimer levels < 1 µg/mL, whose attending physicians made a subjective assessment of high DVT risk. Third, whether screening for preoperative DVT is needed to prevent postoperative symptomatic VTE remains to be clarified. Chang et al reported that routine preoperative DVT evaluation is probably not necessary [22]. However, if patients scheduled for elective surgery for degenerative musculoskeletal disorders have DVT before the surgery, the risks of thrombus extension and fatal PTE could be higher. Whether DVT screening through preoperative D-dimer measurements or ultrasonography can reduce the incidence of symptomatic VTE remains to be verified using large-scale data. Nevertheless, our cross-sectional analysis clearly identified the factors associated with preoperative DVT in patients with degenerative musculoskeletal disorders.