Background
Lumbar disc herniation (LDH) is a common contributor to low back pain and low extremity radicular syndrome, especially in middle-aged and elderly population, presenting a quandary to spine surgeons worldwide regarding to the most appropriate intervention [
1‐
3]. The therapeutic approach ranges from conservative medical interventional management to surgery [
4‐
6]. Various studies have confirmed the effectiveness of surgery in the initial management of LDH [
7]. Nevertheless, the factors influencing intraoperative procedure and prognosis are still not fully understood.
The surgical outcome of patients with LDH can be affected by many factors, such as patient age, gender, autologous blood availability, preoperative hemoglobin level, and the number of spinal decompressed and fused lumbar [
8‐
10]. In addition, other factors may affect the recovery of patients as well, including intraoperative blood loss, operation duration, use of anticoagulants, postoperative drainage volume, immediate drainage, final drainage, and close and open of drainage tubes. It has been reported that intraoperative blood loss and postoperative drainage volume are important for operation and recovery of patients with LDH [
11‐
15]. However, factors that influence intraoperative blood loss and postoperative drainage volume have not been clarified. Moreover, there are no reports on the effects of the methods of using drainage tubes during recovery on the outcome of spine surgery.
Autologous and/or allogeneic blood transfusions are often applied in lumbar spinal surgery [
1‐
3,
16]. The amount of blood transfusion is increased under certain conditions such as increased intraoperative blood loss and prolonged operation. Furthermore, the volumes of blood transfusion and final drainage can also be affected by several other factors, including postoperative drainage volume, immediate drainage, final drainage, and the methods of using drainage tubes (close or open) [
4‐
6].
In this study, the clinical profiles of mid-aged and elderly patients with lumbar disc herniation were analyzed. We investigated various factors that may influence intraoperative blood loss and postoperative drainage volume, including age, gender, and transfusions. The effects of states of drainage tube (open or closed) on final drainage volume were also studied. We believe that the results will help improve knowledge and practice in spine surgery.
Materials and methods
Patients
This retrospective study enrolled 183 patients (109 females and 74 males) with lumbar disc herniation who underwent spinal operation in our department from June 2010 to January 2012. The study was approved by the ethical committee of China-Japan Friendship Hospital (Beijing, China).
Surgical approach
Patients were in the knee-chest or prone positions; all the procedures were conducted under general anesthesia. A midline incision was made to reflect the paraspinous muscles. The interlaminar spaces were made as described previously by McCulloch and Delamarter [
4‐
6]. In almost all cases, medial borders of superior facets were removed in order to have clear views of the related nerve roots. The fragments of disks were removed as described previously by small annular incisions [
4‐
6]. Blood canals were inspected and the foramens probed for bony pathology or residual disk. Nerve roots were decompressed, leaving them freely mobile during operation. The surgical strategies included decompression alone or decompression with fusion.
Clinical data
Clinical data were collected for all patients, including age, sex, operation duration, intraoperative blood loss, hamoglobin and hamatocrit levels preoperatively and at discharge, autologous blood availability, preoperative hemoglobin rate, spinal level decompressed and fused number, duration of hospital stay, and history of other diseases, especially hematological diseases.
Drainage and relevant parameters
For all patients, the plasma drainage tube and disposable drainage bag were emptied every 24 h after the measurement of drainage volume. We collected the data on the drainage time during surgery, intraoperative blood loss, postoperative drainage, and final drainage and operation modes. Drainage time was recorded by the time of blood drainage using a drainage tube during operation.
Data analysis
Patients were divided into different groups according to gender, age, operation modes (one-level and two-level), different transfusions (autologous and allogeneic blood transfusion), close and open of drainage tube, in the presence or absence of anticoagulant, operation time, immediate drainage, and bone graft methods (autogenous bone implantation, autogenous bone and Cage implant, autogenous bone and artificial bone intertransverse posterolateral implantation, autogenous bone and artificial bone implantation and facet joint fusion). Data are presented as mean ± standard deviation (SD). Differences between various groups were analyzed using one-way analysis of variance (ANOVA) or χ2–test with SPSS 13.0 software. A P value < 0.05 was considered statistically significant.
Discussion
Previous studies suggest that the recovery of patients with spinal surgery can be affected by various factors that include body weight, gender, preoperative hemoglobin, fusion levels of lumbar spine, bone grafting, usage of anticoagulants, auto-transfusion, allogeneic blood transfusion, and one-level and two-level operations [
4‐
6,
21‐
24]. However, the effects of intraoperative blood loss, postoperative drainage volume, mode of drainage, and final drainage on patient operation and recovery are poorly understood and require further investigation. In particular, factors determining final drainage need to be investigated. These issues were addressed in this study.
This study provided a comprehensive analysis of factors influencing the operation and recovery of spine surgery. Data demonstrated that operation methods, operation time, autologous and allogeneic blood transfusion and use of anticoagulant affect intraoperative blood loss and postoperative drainage volume. Additionally, the duration of catheter drainage of drainage tube, transfusion, immediate drainage, operation mode, and use of anticoagulant affected final drainage [
21‐
24]. It is worth noting that the mode of drainage (i.e., closed or open) showed no apparent effect on immediate drainage and final drainage volumes.
There were several novel findings in the present study. First, the intraoperative blood loss, postoperative drainage volume, and final drainage are important factors for surgery in spinal patients with lumbar disc herniation. Second, the duration of catheter drainage, autologous blood transfusion, and immediate drainage, one-level and two-level operations, usage of anticoagulant were important for final drainage. Third, closed and open of drainage tube, and states of drainage tubes affected intraoperative blood loss and postoperative drainage volume. Finally, the intraoperative autologous blood transfusion influenced intraoperative bleeding and final drainage.
As the number of patients with LDH continues to increase, spine operation has been far more common [
1‐
3]. Intraoperative blood loss usually serves as marker and predictor of operation and outcome for patients [
4‐
6]. In this study we analyzed various factors, including gender and age, different operative stage (one-level or two-level operations) as well as other factors that may affect intraoperative blood loss and postoperative drainage in patients with lumbar operation. No statistical difference was shown in bleeding quantity, immediate drainage and final drainage between males and females. These findings are contradictory to the results reported in other studies [
10]. The reasons for this observation are not clear, but may be related to sample size (there were limited cases in this study) and different patient groups (i.e., age of patients).
The effects of intraoperative bleeding, transfusion and immediate drainage on final drainage were also analyzed using regression analysis. The results demonstrated that bleeding quantity, transfusion, and immediate drainage affected the final drainage. There was no report on the relationship between the mode of drainage (closed or open) and the final drainage. The results showed that states of drainage tube did not affect the final drainage. It is suggested that future studies focus on additional factors that may be important for intraoperative blood loss and postoperative drainage. In addition, the effects of intraoperative blood loss and postoperative drainage on successful spinal operation and patient recovery should be further investigated.
The factors identified as contributors to total blood loss and final drainage volumes in the present study included operation methods, operation time, autologous and allogeneic transfusion and use of anticoagulants. These findings indicate that blood loss and final drainage can be controlled by the surgeon. There was a significant clinical impact on blood loss by using anticoagulants (Antifibrinolytics).
A drainage system was used in spine surgery in the present investigation. Because the drainage was always closed, suction or no suction was the only choice. In addition, clinical practice between China and Western countries has remarkable differences [
1‐
8]. For example, the duration of hospital stay is often much shorter in Western world than that in China.
There were four fusions per levels, 46 decompressions and 32 herniated discs in the present study. Although one is quite surprised to find herniated discs in a study on transfusion, transfusion indeed plays important roles in surgery of patients with herniated discs, just as shown in the present study. It is obvious that the data showed that there were differences in blood loss between autologous transfusion groups and non transfusion groups. Indeed, it was not required an autologous donation for single level fusion or herniated disc surgery in the present study.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
HZ participated in the design of the study and performed the statistical analysis. HZ drafted the manuscript. HZ, ZL, HS, MT, FY, LL, JZ conceived of the study, and participated in its design and coordination and helped to draft the manuscript. All authors read and approved the final manuscript.