Spinal fracture is a common injury that most often occurs in the thoracolumbar spine. Traditional open posterior surgery for reduction and stabilization of unstable thoracolumbar fractures with pedicle screws is still nowadays the gold standard. However, traditional posterior approach requires splitting of the paravertebral muscles and ligaments, which is associated with perioperative bleeding, possibly increased infection rate, back pain, and delayed functional rehabilitation.Citation1–3 The Wiltse paraspinal approachCitation4, is associated with less bleeding and less tissue injury through dissection, and it was thought to minimize the negative consequences of the traditional open posterior approach since it was associated with good outcomes.
Spinal surgery may be associated with significant blood loss, especially in multilevel procedures (5). When assessing total blood loss (TBL) during spinal fusion surgery, the standard is to measure intraoperative blood loss (IBL) and postoperative blood loss (PBL), which ignores so-called “hidden blood loss” that has been found to be significant in the field of surgery.Citation5,Citation6
Hidden blood loss (HBL) negatively affects patients’ outcomes, such as medical complications and prolonged hospitalization time. The percentage of HBL was reported to be approximately 45% of TBL, according to the reports of Smorgick et al.Citation6 HBL is a significant portion of TBL in the patients after spinal fusion surgery, which can result in the increased allergenic blood transfusion requirements.Citation7 Potential problems associated with allergenic blood transfusion include disease transmission, transfusion reactions, and infections.
Posterior fusion of the spine involves a substantial HBL, which is not recognized by the usual practice of assessing the IBL and PBL. With development of new surgical techniques and introduction of new spinal instrumentations, percutaneous approaches have been used for fixation of thoracolumbar fractures. Percutaneous fixation may reduce injury to the spinal muscles and it was shown to be associated with minimal intraoperative bleeding, less pain and infection, and successful radiological and clinical result.Citation8
The authors of a quite recent studyCitation9 performed a retrospective clinical review to determine whether there is a difference in the amount of HBL during operative treatment of a single-level A1, A2, and A3 AO/type thoracolumbar fractures using three different approaches (percutaneous approach, Wiltse approach, and conventional open approach) with 6 pedicle screw construct. The authors transfused no patient in any group. IBL was given by the measured suction loss and blood loss in swabs, and recorded by the anesthetists. In addition, a complete blood count, including Hct and Hb levels, was obtained in all patients preoperatively and on the second or third postoperative day for calculation of blood loss. Wound drainage was not done in any patient. The authors saw little blood loss following surgery and therefore, any postoperative blood loss was ignored. The method of Sehat et al.Citation10 was used to calculate the HBL.
The authorsCitation9 found that the TBL of the percutaneous group was markedly less than that in the open surgery and paraspinal group, while the greatest amount of TBL was observed in the open group. The HBL in the percutaneous group was 240 ± 61 ml, in paraspinal group 313 ± 138 ml, and in open group 382 ± 153 (P < 0.001). However, in terms of the absolute values of TBL, blood loss was much greater than that reported in most previous studies, and the decreases in Hb levels in all three groups were much too high to attribute to visible blood loss, which may support the presence of substantial HBL during surgical treatment of thoracolumbar fractures.
The limitations in this study were: the small number of patients in each group; the authors in calculation of blood loss, the blood volume was assumed to be constant throughout the perioperative period (postoperative Hct was estimated on 2nd and 3rd postoperation); and the authors did not examine other potential factors influencing HBL levels.
In conclusion, the authors showed a substantial HBL in the surgical treatment of thoracolumbar fractures that probably has been underestimated in previous studies. The authors recommend spine surgeons to be aware of HBL, to avoid complications related to blood loss, and to improve patient rehabilitation and I totally agree with the authors’ recommendation with Ht and Hb measurement for the first postoperative days in patients undergoing open or percutaneous spinal surgery along with other medications that may be received by the patients. Use of antifibrinolytic agents as TXA may decrease TBL and particularly HBL.
Declaration of interest
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References
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- Chen Ze-Xin, Sun Ze-Ming, Jiang Chao, et al. Comparison of Hidden Blood Loss Between Three Different Surgical Approaches for Treatment of Thoracolumbar Fracture. J Invest Surgery. (in press).
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