Overall, this is a well-designed study that helps answer an
important question for spine surgeries. The main strengths of
the study are that it was randomized, blinded and included
enough patients to power the statistical analyses. Reducing
blood loss and blood transfusions in the perioperative period
is beneficial to patients and the health system. Research has
shown that blood transfusions increase the risk of infection,
increase hospital costs, and can lead to poorer outcomes for
patients. Several prior studies have shown the effectiveness of
TXA in cardiac surgery, liver transplantation and orthopedic
joint arthroplasty. The current study supports the use of TXA
for spinal surgery where there had previously been less supporting evidence. The authors conclude that the two doses of
TXA they studied (each 15 mg/kg, one dose before anesthesia
induction and the second dose given 3 hours later) are effective in reducing blood loss and limiting blood transfusions
during complex spine surgery.
This study does have some limitations. The primary limitation concerns the dosing of TXA. A variety of TXA dosing
regimens are discussed in the literature, which the authors do
acknowledge, but only one dosing regimen was studied in this
trial. The authors chose to use two doses of 15 mg/kg, spaced
apart by 3 hours, which has not previously been studied in
spinal surgery. It is of note that the authors did not clearly
state that the control group received two doses of placebo, as
did the experimental group, to maintain blinding.
This study also included a wide variety of cases and surgical indications, ranging from multilevel decompression
to tumor and scoliosis cases. This may help to increase the
generalizability of the study, but also results in wide ranges of
data. For example, the EBLs ranged from 80 mL to 4000 mL.
The highest EBL in the TXA group (4000 mL) was seen with
scoliosis surgery, but the highest EBL in the control group
(3500 mL) was seen with laminectomy with instrumentation
with PLIF or TLIF or osteotomy. The researchers note that the
cases were similarly divided between both groups. Although
this does help address this concern, the variability within the
Direct or indirect remuneration: royalties, stock ownership, private
investments, consulting, speaking and/or teaching arrangements, trips/travel.
Position held in a company: board of directors, scientific advisory board, other
office. Support from sponsors: endowments, research–investigator salary,
research–staff and/or materials, grants, fellowship support. Other
Degree of support:
Level A. $100 to $1000 Level F. $100,001 to $500,000
Level B. $1,001 to $10,000 Level G. $500,001 to $1M
Level C. $10,001 to $25,000 Level H. $1,000,001 to $2.5M
Level D. $25,001 to $50,000 Level I. greater than $2.5M
Level E. $50,001 to $100,000
study groups is still notable.
Furthermore, quantifying intraoperative blood loss is challenging. The authors defined how they determined intraoperative blood losses, but this can be multifactorial and difficult to
quantify. Their postoperative blood loss numbers were solely
based on drain outputs and did not involve calculations using
hematocrit or urine.
Further, several aspects of this research may not be transferrable to other institutions. For example, controlled hypotension was used in all cases in this study. Although this was
consistent across all of the cases, this is not standard among
all institutions. The threshold for transfusion was set at a
hematocrit level of 30% or lower. Again, although consistent
across all of the cases, this is a higher threshold than used at
many other centers. Finally, the average hospital length of stay
was 12. 5 days in the control group and 11. 1 days in the TXA
group, which is likely longer than average for patients in the
US. This likely does not affect the research results, since the
focus was on the surgery and the first 24 hours after surgery.
Ultimately, this was a very well performed prospective,
double-blind, randomized controlled study that found a
reduction in blood loss and blood transfusions for complex
spinal thoracolumbar surgeries with the use of two doses of 15
mg/kg of TXA (administered before anesthesia induction and
three hours later). Even though only one dosing regimen was
studied among a spectrum of cases, the results are encouraging. Looking forward, more research is needed to delineate
the optimal dosing for TXA and to determine for which spinal
cases this should be considered.
R Gaja: nothing to disclose.
J Grauer: Consulting: Stryker (D), Medtronic (0), Bioventus (B). Other
Office: NASS (Nonfinancial, Program Committee Co-chair, 2017);
LSRS (Nonfinancial, Program Committee Co-chair, 2016, 2017);
Other: Legal consulting (legal reviews over the past year).