We appreciate the insightful comments made by the authors of the letter regarding our article entitled “The efficacy and safety of topical saline irrigation with tranexamic acid on perioperative blood loss in patients treated with PELD.”[1] Thank you for taking the time to assess our manuscript and for the opportunity to respond to your comments.

CONCERN 1: In our study, the main indicator we observed was total blood loss (TBL), which was calculated by the formula used by Nadler et al[2] and Gross.[3] This is a generally applicable formula for calculating blood loss. Our study found the TBL to be more than 300 mL, which is far beyond our common sense. As a minimally invasive operation of the spine, percutaneous endoscopic lumbar diskectomy (PELD) has the advantages of less trauma, rapid recovery, and obvious clinical effect. In the past, it was generally believed that the total perioperative blood loss of minimally invasive spinal surgery was low, but recent studies have found that the TBL of percutaneous kyphoplasty (282 mL) and percutaneous vertebroplasty (306 mL) are higher.[4] [5] This is far beyond the common sense of many spinal surgeons. Considering the need to establish a channel for endoscopic surgery, there is an ineffective cavity to further increase TBL. Jitpakdee et al[6] reported a range of intraoperative blood loss (IBL) from 10.9 to 23.35 mL for interlaminar endoscopic diskectomy without any systemic or local use of tranexamic acid (TXA). We found that calculation of the amount of IBL was not mentioned in their study. In our study, a spectrophotometer was used to calculate the hemoglobin concentration in the flushing fluid, and the calculated IBL was about 40 mL. Meanwhile, Qu et al[7] recently reported the IBL in PELD surgery to be approximately 40 mL, which aligns with the findings of our study.

CONCERN 2: We agree with Kim et al that our study mainly focuses on the preoperative and intraoperative intravenous administration of TXA. As they pointed out, we also encountered this problem prior to conducting the study and it troubled us for a long time. After reviewing several published articles, we found the most severe toxicity of TXA to the central nervous system to be its epileptogenic effect, which has been primarily observed in cardiovascular surgeries involving high doses of TXA. However, to the best of our knowledge, there are only a few reports of significant side effects caused by TXA in orthopaedic surgery. A meta-analysis of 129 studies involving 10,488 patients conducted between 1972 and 2011 found that TXA does not elevate the risk of myocardial infarction, cerebral infarction, seizures, or venous thrombosis.[8] In recent years, there have been two cases of seizures caused by TXA injection during spinal surgery. In one case, the patients underwent lumbar internal fixation; 0.5 g TXA was injected intravenously before operation. A dural tear was identified during the operation, resulting in cerebrospinal fluid outflow. The surgeon did not consider the potential central nervous system complications of using TXA. One gram of TXA was administered into the epidural space during the operation, and the drainage tube was clamped after operation. The patient had unique clinical symptoms of epilepsy within 30 minutes after the operation, that is, perineal and sacral pruritus.[9] The authors considered that the dura mater was ruptured and TXA entered the cerebrospinal fluid, causing central nervous system reaction to TXA drugs and resulting in epilepsy. The other patient, a 66-year-old Japanese woman, was planned to undergo lumbar interbody fusion, with 1 g TXA injected intravenously before operation and 2 g immediately after operation.[10] TXA has a half-life of 1 to 1.5 hours in the bloodstream and is eliminated by the kidneys within 3 to 4 hours.[11] For local administration of TXA, the guidelines recommend that 1 g TXA be immersed in the surgical area for 5 minutes before suturing the incision.[12] In our study, continuous low-concentration local flushing of TXA may not lead to drug accumulation. Moreover, all the surgeons involved in the operation had high-level skills and took necessary measures to prevent any potential damage to the dural tear during the procedure. In the case of dural tear, TXA flushing is stopped in time. Fortunately, no intraoperative dural injury was found in our study.

CONCERN 3: We acknowledge that this is our negligence in preparing the study. During the study period, patients with risk factors for hypercoagulable state, thromboembolic events (such as atrial fibrillation), or previous history of epilepsy were not eligible for TXA treatment.

CONCERN 4: Krohn et al[13] used TXA before wound closure, but without local concentration of TXA during operation, and the result found that TXA could not play a role in reducing the amount of blood loss. However, local continuous low concentration of TXA irrigation was used and the result confirmed that TXA can improve the clarity of intraoperative visual field, quickly stop bleeding from local small vessel rupture, and reduce the IBL during operation in our study.

We again thank the authors of the letter for their interest and expectations in the application of TXA in PELD surgery, as well as their valuable suggestions. We hope that our answers satisfy their questions and other readers of this prestigious journal.

Received: 08 December 2023

Accepted: 20 December 2023

Accepted Manuscript online:
27 December 2023

Article published online:
12 February 2024

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