Lesser Blood Loss With Scoliosis Surgery Seen in Tranexamic Acid Use

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by Steve Bryson PhD |

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Tranexamic acid (TXA) effectively reduced blood loss by over 50% during surgery to correct for scoliosis caused by spinal muscular atrophy (SMA), a 20-year study demonstrated.

The medication also lowered the volume of blood transfused during surgery by 60%, and reduced the amount of crystalloid solutions used to maintain blood volume.

Because higher crystalloid and blood transfusion volumes are associated with lung (pulmonary) complications after surgery, the researchers noted that TXA may help alleviate these problems.

The study, “Intravenous Tranexamic Acid Reduces Blood Loss and Transfusion Volume in Scoliosis Surgery for Spinal Muscular Atrophy: Results of a 20-Year Retrospective Analysis,” was published in the International Journal of Environmental Research and Public Health.

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Scoliosis — curvature of the spine — commonly occurs in SMA patients due to progressive muscle weakness and atrophy (shrinkage) caused by a lack of nerve cells that control voluntary muscle movement. SMA scoliosis can impact spinal balance, make sitting difficult, and may affect breathing.

In some cases, surgery is required to help stabilize the spine and trunk, improve sitting balance, ease back pain, and preserve lung function.

However, patients undergoing spinal surgery for neuromuscular scoliosis are at an increased risk of surgical bleeding, with some losing more than 50% of their total blood volume. These patients are also at a higher risk of needing intraoperative fluid and blood transfusions, and of developing subsequent pulmonary complications.

TXA, infused directly into the bloodstream (intravenously), is known to be effective at treating or preventing excessive blood loss from trauma or major surgery, including during corrective surgeries in people with other neuromuscular diseases. Because of the limited number of patients, however,  TXA’s usefulness during SMA scoliosis surgery is still unclear.

Since 2009, clinicians based at the Kaohsiung Medical University Hospital in Taiwan have used TXA to reduce bleeding in SMA patients undergoing scoliosis surgery. The team examined the medical records from these procedures, given before and after 2009, to report on TXA’s effectiveness.

“To the best of our knowledge, no study has investigated the effectiveness of intravenous TXA in scoliosis surgery in SMA patients,” the researchers wrote.

Their study included 15 patients (mean age, 12.7) treated with TXA during surgery: 10 females, and five males. Of them, 12 were diagnosed with SMA type 2, and two with SMA type 3.

Records of 15 SMA patients (mean age, 14.5) not given TXA during surgery were also examined — nine females and six males — 12 of whom had SMA type 2 and three with SMA type 3. There were no significant differences between the two groups regarding the percentage of red blood cells by volume, platelet counts, surgical time, or spinal curvature before or after surgery.

Results showed that, compared to the control group, those treated with TXA had less overall estimated blood loss, defined as the total blood loss volume collected by suction and gauze absorption during surgery, but the difference was not statistically significant.

In contrast, the TXA group had a statistically lower average of total blood volume loss (TBVL), calculated from the estimated blood loss and the estimated total blood volume of the patient. The mean TBVL for the TXA group was 52.1% and 106.7% for the control group; thus, “TXA administration decreased the mean rate of TBVL by 51%,” the team wrote.

During surgery, the mean blood volume infused into the TXA group was significantly lower than that in the control group — 498.7 vs. 1250 mL — representing a 60% reduction.

The volume of crystalloid solutions containing electrolytes, such as sodium and chloride, to maintain liquid volume was 26% lower in the TXA group than in control patients. The overall transfusion volume was 35% less.

Intubation time during surgery was also shorter in the TXA group, and these patients had fewer pulmonary complications than controls (5 vs. 8), but none of these differences were statistically significant.

Patients who experienced pulmonary complications were more likely to receive more crystalloid solution and higher total transfusion volumes, compared with those without these complications.

To further examine these findings, researchers set an overload volume limit of transfused crystalloid solution at 113 mL/kg to analyze the relationship between TXA, crystalloid volume, and pulmonary complications.

The TXA group had a significantly lower rate of excess crystalloid volume than did controls. At the same time, the pulmonary complications were significantly higher in the crystalloid volume overload group than those in the non-overload group. In patients given high volumes of fluids, whether in the TXA or control group, pulmonary complications were more likely, but not by a statistically significant degree.

“In conclusion, this study suggests that TXA can effectively decrease the intraoperative blood loss and crystalloid transfusion volume during posterior spinal fusion for SMA scoliosis,” the researchers wrote.

“Furthermore, TXA administration in SMA patients undergoing scoliosis surgery can reduce the incidence of crystalloid fluid overload, allow earlier postoperative extubation, and thereby reduce postoperative pulmonary complications,” they added.