Does Tranexamic Acid Increase the Incidence of Thromboembolism After Spinal Fusion Surgery?

STUDY DESIGN: This was a retrospective analysis of prospectively collected data. OBJECTIVE: To investigate the incidence of thromboembolism in patients who received tranexamic acid (TXA) after lumbar spine fusion and determine the diagnostic value of lower limb duplex sonography as a screening test. SUMMARY OF BACKGROUND DATA: TXA is effective in reducing blood drainage in spine fusion surgery but some studies have reported increased incidence of venous thromboembolism associated with TXA. MATERIALS AND METHODS: One hundred twenty-two patients who underwent lumbar fusion for degenerative spinal disease received intravenous TXA in doses equivalent to 10 mg/kg for 48 hours after surgery. As a control group, 85 patients received intravenous administration of the same amount of normal saline. D-dimer levels were checked on the day of admission and the seventh postoperative day (POD#7). All patients underwent duplex sonography on POD#7, and patients with abnormal results were further evaluated with computed tomography angiography and pulmonary arterial angiography. RESULTS: None of the patients showed symptoms of deep vein thrombosis (DVT). Suspicious signs of DVT were observed in 5 patients in the TXA group and 4 patients in the control group in lower limb duplex sonography. Finally, DVT was confirmed by computed tomography angiography in one of 122 patients (0.8%) in the TXA group and in one of 85 patients (1.2%) in the control group. D-dimer levels on POD#7 were higher in the patients with DVT than in patients without DVT. Average postoperative blood drain was 421.3±133.1 mL in the TXA group and 635.2±151.2 mL in the control group (P<0.001), which showed TXA was effective to reduce postoperative hemorrhage. CONCLUSIONS: The incidence of thromboembolism after using TXA in lumbar fusion surgery was 0.8%, as comparable as the incidence of thromboembolism in the control group. Lower limb duplex sonography is not recommended for screening test of DVT because of high false-positive rate. LEVEL OF EVIDENCE: Level III.

Does Lordotic Angle of Cage Determine Lumbar Lordosis in Lumbar Interbody Fusion?

STUDY DESIGN: Retrospective, radiological analysis. OBJECTIVE: To determine that 15° lordotic angle cages create higher lumbar lordosis in open transforaminal lumbar interbody fusion (TLIF) than 4° and 8° cages. SUMMARY OF BACKGROUND DATA: Restoration of lumbar lordosis is important to obtain good outcome after lumbar fusion surgery. Various shapes and angles of cages in interbody fusion have been used; however, it is not proved that lordotic angle of cages determine lumbar lordosis. METHODS: Sixty-seven patients were evaluated after TLIF using 15° cages and screw instrumentation. For comparison, TLIF using 4° lordotic angle cages in 65 patients and 8° cages in 49 patients were analyzed. Lumbar lordosis angles, segmental lordosis angles, disc height, and bony union rate were measured on the radiographs. RESULTS: The lumbar lordosis was 31.1° preoperatively, improved to 42.9° postoperatively, and decreased to 36.4° at the last follow-up in the 15° group. It was 35.8° before surgery, corrected to 41.5° after surgery, and changed to 33.6° at the last follow-up in the 4° group. In the 8° group, it was 32.7° preoperatively, improved to 39.1° postoperatively, and decreased to 34.5° at the last follow-up. These changes showed statistical significances (P < 0.001). The segmental lordosis at L4-5 was 6.6° before surgery, 13.1° after surgery, and 9.8° at the last follow-up in the 15° group. It was 6.9°, 9.5°, and 6.2° in the 4° group and 6.7°, 9.8°, and 8.1° in the 8° group, respectively (P < 0.001). The disc height restoration was better in the 15° group than in the 4° and 8° groups (P < 0.001). Bony union rate was not significant among the three groups (P = 0.087). CONCLUSION: The lordotic angle of the cages determined restoration of lumbar lordosis after TLIF. Cages with sufficient lordotic angle showed better restoration of lumbar lordosis and prevention of loss of correction. LEVEL OF EVIDENCE: 4.

Clinical features of atypical femur fracture.

OBJECTIVES: We aim to elucidate the clinical outcomes of bisphosphonate-associated atypical femoral fracture and the clinical results depending on the bisphosphonate therapy period. METHODS: Twenty cases involving 15 patients who had been diagnosed with atypical femoral facture between 2004 and 2014 and who had been followed up for at least 12 months were retrospectively analyzed. The control group was composed of 15 typical femoral facture patients. We used plain radiography and physical examinations to determine the period of time required for fracture healing as well as complication occurrence. We investigated the bisphosphonate administration status and duration and the names of its components, bilateral fracture occurrence status, the period of time required for bone union, and reoperation or bone graft status due to nonunion. RESULTS: Revision surgery involving a bone graft was performed due to nonunion in 1 out of 15 cases. Except in one revision case, the duration of the union was 11.9 months on average in 14 cases of atypical fracture patients, and 4.3 months on average in the control group. This difference was statistically significant (p < 0.05). The bisphosphonate administration duration was positively correlated with the union period (p < 0.05). In contrast, there was no statistically significant correlation between the bisphosphonate administration duration and the incidence of bilateral atypical fractures (p > 0.05). CONCLUSIONS: Atypical femoral fractures required more time for bone union than typical ones and prolonged bisphosphonate administration led to a longer period of time required for bone union.