Original Article
Significant Blood Loss in Lumbar Fusion Surgery for Degenerative Spine Yu-Hua Huang1,2 and Chien-Yu Ou1,3
OBJECTIVE: Lumbar fusion is a widely used procedure for degenerative spine diseases but frequently is accompanied with substantial surgical blood loss. We aimed to investigate the risk factors for significant intraoperative blood loss and the influence of excessive bleeding on postoperative complications in patients undergoing fusion for degenerative lumbar spines.
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METHODS: For this retrospective study, we enrolled 199 patients who had undergone lumbar fusion surgery for degeneration. The definition of significant blood loss at operation was 500 mL or more in blood volume. The patients were subdivided into 2 groups on the basis of whether significant blood loss was present (n [ 107) or not (n [ 92).
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RESULTS: The incidence of significant blood loss during lumbar fusion was 53.8%. In the multivariate logistic regression model, the independent risk factors for significant blood loss included body mass index (P [ 0.027), extreme spinal canal narrowing (P [ 0.023), spine fusion segments >1 level (P [ 0.008), and transforaminal lumbar interbody fusion (P [ 0.006). Significant blood loss in lumbar fusion was associated with a greater incidence of postoperative complications (P [ 0.002). The length of hospital stay for patents with excessive bleeding was prolonged significantly (P [ 0.045).
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CONCLUSIONS: Because substantial bleeding in lumbar fusion is associated with a greater incidence of morbidities and prolonged length of hospital stay, attention to the risk factors for significant blood loss is important in the preoperative assessment and postoperative guidance for the level of care.
-
INTRODUCTION
A
s early as 1911, Hibbs and Albee described fusion surgery of the spine that aimed to stabilize diseased vertebrae by using bone grafts (2). Since then, fusion surgery has become a widely used therapy for various spinal conditions, and one of the common indications is degenerative lumbar spine diseases (17). Although this procedure is technically familiar to surgeons, it is not without morbidities. Spinal fusion is accompanied frequently by substantial blood loss and is among the top surgical procedures associated with blood transfusion (20). Significant intraoperative blood loss of 500 mL or greater, which increases postoperative morbidity and mortality in patients undergoing major noncardiac surgery, has been reported (3, 22, 23). In addition, fusion of degenerative lumbar spines usually is carried out among geriatric patients. Older patients are especially vulnerable to the detrimental effects of blood loss and anemia because of the limited physiological reserve (6, 12). Blood loss during surgery also leads to the need of red cell, platelets, or factor transfusions, and the potential for immunological reaction and infection transmission must be considered. As a result, the ability to identify the risk of significant blood loss in patients undergoing lumbar fusion procedures is quite important and may guide the level of care and offer modifiable targets to alleviate the effect of morbidities. In this study, we retrospectively collected clinical data and assessed risk factors for significant blood loss during lumbar fusion surgery for degenerative spine diseases. We also investigated the impact of significant intraoperative blood loss on postoperative complications. MATERIALS AND METHODS Data Collection This retrospective cohort study was carried out at Kaohsiung Chang Gung Memorial Hospital, a 2715-bed medical center in
Key words - Blood loss - Complication - Degenerative spine disease - Lumbar fusion
From the 1Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; 2Department of Neurosurgery, Kaohsiung Municipal Min-Sheng Hospital, Kaohsiung, Taiwan; and 3 Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan
Abbreviations and Acronyms ASA: American Society of Anesthesiologists BMI: Body mass index CSF: Cerebrospinal fluid PLF: Posterolateral lumbar fusion PLIF: Posterior lumbar interbody fusion TLIF: Transforaminal lumbar interbody fusion
Citation: World Neurosurg. (2015) 84, 3:780-785. http://dx.doi.org/10.1016/j.wneu.2015.05.007
780
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To whom correspondence should be addressed: Chien-Yu Ou, M.D. [E-mail: [email protected]]
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.05.007
ORIGINAL ARTICLE YU-HUA HUANG AND CHIEN-YU OU
Taiwan. After obtaining consent from the institutional review board, we reviewed the records of patients who had undergone lumbar fusion surgery for degenerative spine diseases in the neurosurgical department from September 2012 through June 2013. We excluded patients who had had previous spine surgeries. A total of 199 patients were enrolled for analysis. Trained research staff collected clinical data, consisting of the patients’ baseline information, body mass index (BMI), findings of laboratory examinations, and American Society of Anesthesiologists (ASA) Physical Status Classification (1). Details of the operations were recorded, and total intraoperative blood loss was calculated as the sum of blood in suction containers and soaked sponges. The definition of significant operative blood loss was 500 mL or more of blood volume (3, 22, 23). Preoperative Evaluation Diagnosis of degenerative lumbar spine disease was established on the basis of the history and physical examination in conjunction with magnetic resonance imaging scans. In addition, anteroposterior translation or intervertebral rotation was examined on lateral flexion/extension and anteroposterior radiographs. All patients experienced low back pain, lower extremity pain, or other neurologic deficits resulting from spinal stenosis or localized lumbar/lumbosacral segmental instability at the L1eS1 levels. The levels of the affected vertebrae with a compressed dura sac or nerve roots were determined. The degree of spinal canal narrowing was evaluated on the basis of the cerebrospinal fluid (CSF)/rootlet ratio as seen in axial T2 images, and was graded as A, B, C, and D (Grade A stenosis, i.e., there is clearly CSF visible inside the dural sac, but its distribution is inhomogeneous; Grade B stenosis, i.e., the rootlets occupy the whole of the dural sac, but they can still be individualized; Grade C stenosis, i.e., no rootlets can be recognized, the dural sac demonstrating a homogeneous gray signal with no CSF signal visible; Grade D stenosis, i.e., in addition to no rootlets being recognizable, there is no epidural fat posteriorly) (18). Grade D was defined as extreme spinal canal narrowing in this study. Surgical Strategy and Techniques Lumbar spine fusion was indicated when the patients had clinical and/or radiographic signs of instability or were at risk of iatrogenic instability after decompression. The patients underwent one of the following 3 fusion procedures: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), or posterolateral lumbar fusion (PLF). In brief, neural decompression was carried out by removing the degenerated ligamenta flava, lamina of vertebrae, or protruded disc. In cases involving PLIF or TLIF, the cage was placed after cleaning the disc space. For PLF, removed lamina with or without iliac bone was used as autologous bone graft and placed on the transverse process of the vertebra. Pedicle screw instrumentation was performed on the basis of the stability of the fused spines, as determined by the surgeon. There was no artificial disc replacement, corpectomy, osteotomy, kyphectomy, or insertion of spinal spacers or dynamic stabilizing devices in our patient group. Postoperative Complications The outcome for this study was postoperative complications during hospitalization. The following events were defined as
WORLD NEUROSURGERY 84 [3]: 780-785, SEPTEMBER 2015
BLOOD LOSS IN LUMBAR FUSION FOR DEGENERATIVE SPINE
complications: acute renal failure, myocardial infarction, stroke, delirium, deep venous thrombosis, pulmonary embolism, wound disruption, deep surgical-site infection, pneumonia, urinary tract infection, sepsis, systemic inflammatory response syndrome, and >4 U red blood cell transfusion within 72 hours after operation. All deaths also were considered postoperative complications. Statistical Analysis Data were analyzed using SPSS version 20.0 (IBM SPSS Statistics, Armonk, New York, USA). Descriptive statistics are presented as frequencies (percentages) or as mean and SD. Categorical variables were compared using the c2 test or Fisher exact test. Continuous variables were assessed using the Student’s t test or ManneWhitney U test. All parameters with a P < 0.05 were entered into multivariable logistic regression to adjust for independent risk factors of significant blood loss during lumbar fusion surgery. The results were expressed as odds ratios with 95% confidence intervals. A P < 0.05 was considered to be statistically significant. RESULTS Patient Characteristics The 199 patients who underwent lumbar fusion surgery for degenerative spine diseases included 90 men and 109 women. The mean age was 61.8 (SD, 12.3; range, 20e83) years. Underlying medical conditions included 40 cases of diabetes mellitus, 110 of hypertension, 6 of coronary artery disease, 1 patient receiving anticoagulant therapy, and 9 patients undergoing antiplatelet therapy. The anticoagulant and antiplatelet treatments were halted before surgery. Average BMI was 26.8 (SD, 3.6; range, 18e40) kg/m2. The mean hemoglobin level before operation was 13.2 (SD, 1.7; range, 9e19) g/dL. The number of patients with ASA classification I, II, and III was 7, 101, and 91, respectively. There were 56 patients with extreme spinal canal narrowing on the basis of findings on magnetic resonance imaging. Lumbar Fusion Surgery The mean blood loss during operation was 554.3 (SD, 346.3; range 50e1850) mL. Figure 1 shows the distribution of the volume of
Figure 1. Distribution of volume of surgical blood loss in lumbar fusion.
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BLOOD LOSS IN LUMBAR FUSION FOR DEGENERATIVE SPINE
surgical blood loss for the 199 patients. Significant blood loss (500 mL) was identified in 107 (53.8%) patients. There were 27 patients undergoing perioperative allogenic red cell transfusion. The mean duration of operation was 5.9 (SD, 1.9; range 2e12) hours. The spinal fusion segments were as follows: 1 level in 113 patients, 2 levels in 69 patients, 3 levels in 16 patients, and 4 levels in 1 patient. Thirty-nine and 114 patients underwent PLIF and TLIF, respectively; PLF was performed in 46 patients. In all, 164 patients had pedicle screw instrumentation. Risk Factors for Significant Intraoperative Blood Loss In a comparison of clinical features of patients with or without significant blood loss, statistical analysis identified the following parameters with a P < 0.05: age (P ¼ 0.006), diabetes mellitus (P ¼ 0.021), BMI (P < 0.001), preoperative hemoglobin (P ¼ 0.004), ASA classification (P ¼ 0.004), extreme spinal canal
narrowing (P < 0.001), spine fusion segments >1 level (P < 0.001), TLIF (P ¼ 0.012), and duration of operation (P ¼ 0.009) (Table 1). All of these factors were entered into multivariable regression analysis, and the independent risk factors for significant blood loss in lumbar fusion included BMI (P ¼ 0.027), extreme spinal canal narrowing (P ¼ 0.023), spine fusion segments >1 level (P ¼ 0.008), and TLIF (P ¼ 0.006) (Table 2). We further stratified the patients into 3 subgroups on the basis of BMI (normal weight: BMI 1 level
2.78 (1.31e5.89)
0.008
TLIF
2.97 (1.37e6.43)
0.006
Duration of operation
1.23 (0.99e1.51)
0.057
CI, confidence interval; ASA classification, American Society of Anesthesiologists Physical Status Classification; TLIF, transforaminal lumbar interbody fusion. Values in bold indicate statistical significance.
delirium, 1 of wound disruption, 2 of deep surgical-site infection, 4 of pneumonia, 11 of urinary tract infection, 2 of systemic inflammatory response syndrome, and 2 red cell transfusions >4 U. There was no in-hospital mortality. The patients were subdivided into 2 groups on the basis of whether significant blood loss was present, and the intergroup differences in the observed rates of complications were statistically significant (P ¼ 0.002). The mean duration of hospital stay was 9.8 (SD 4.9) and 8.6 (SD 3.1) days for patients with and without significant blood loss, respectively (P ¼ 0.045) (Table 1).
Figure 2. Box plot for surgical blood loss in lumbar fusion using body mass index (BMI) stratification.
WORLD NEUROSURGERY 84 [3]: 780-785, SEPTEMBER 2015
DISCUSSION Lumbar fusion for degenerative spine disease is among the most common surgical procedures and has an increasing frequency annually (17). With more and more attention being paid to patient safety, the problems with this procedure are under closer investigation. In this study, the rate of significant blood loss was 53.8%, which was comparable with the abundant intraoperative hemorrhage of spinal fusion in the literature (7). Rates of mortality and morbidity were reported to be related to blood loss during surgery, increasing prominently for patients who lost more than 500 mL (3). In contrast, an increase in the rate of intraoperative blood transfusion accompanied a decrease in postoperative mortality for this high-risk population (23). Our results also confirmed that significant blood loss in lumbar fusion was associated with a greater incidence of postoperative complications. As expected, the length of hospital stay for patients with substantial bleeding was prolonged concomitantly. An increased understanding of the risks of significant blood loss is pivotal to improving surgical outcomes. In addition, careful patient assessment offers an opportunity to control medical costs. Several predictive factors of blood transfusion requirements in patients undergoing spine fusion, such as female sex, age, low preoperative hemoglobin, high comorbidity score, number of fused vertebrae, or surgical approach, have been documented (15, 24). However, the delivery of blood transfusion depends not only on the blood loss amount but also on multiple determinants, including those of patients, surgeons, or anesthesiologists, and a large variation exists in hospitals’ practices for patients with significant surgical blood loss (23). Therefore, calculating the volume of blood loss and evaluating the parameters related to surgical bleeding can be more direct and practical for risk identification. In this series, we demonstrated the 4 independent risk factors for significant blood loss in lumbar fusion, including BMI, longsegment spinal fusion, extreme spinal canal narrowing, and TLIF. In a study of 112 patients undergoing revision lumbar spine surgery, Zheng et al. (25) reported body weight was one of the factors predicting intraoperative blood loss. Shamji et al. (21) found that obese and morbidly obese patients had increased transfusion requirements during thoracolumbar and lumbar spine fusion, independent of the surgical approach used. Our results consistently showed BMI was a significant variable in multivariable logistic regression, and the difference in the average volume of surgical blood loss between patients with normal weight and obese patients was up to 227 mL (P ¼ 0.008). One reasonable explanation for excessive bleeding may be the relationship between obesity and intra-abdominal pressure. Reducing intra-abdominal pressure, which in turn lowers vertebral venous pressure, is a documented method for controlling blood loss during lumbar spine surgery (13, 19). However, a greater baseline level of intra-abdominal pressure was observed in obese patients (5). Besides, a direct compressive effect from the abdominal adipose tissue when in a prone position also may affect intra-abdominal pressure and result in an increase of blood loss from epidural veins. A greater number of fused vertebrae is an established risk factor for blood transfusion in spinal surgery (14, 16, 24). It is not surprising that our results support the greater incidence of significant
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ORIGINAL ARTICLE YU-HUA HUANG AND CHIEN-YU OU
BLOOD LOSS IN LUMBAR FUSION FOR DEGENERATIVE SPINE
blood loss in lumbar fusion of more than 1 level. Long-segment fusion needs extensive exposure of the spine, which means extensive muscle and soft-tissue detaching from the vertebrae. The more raw surfaces of muscle and bone are exposed, the more blood will be lost. Also, extreme spinal canal narrowing is a factor associated with substantial bleeding, and we found that it carried a 2.8-fold greater risk of significant blood loss in lumbar fusion. Severe compression of the spinal canal probably results in tenuous blood return and subsequent engorgement of epidural veins. In addition, increased epidural adhesion may be accompanied with an advanced degeneration course. Therefore, manipulation or coagulation of vascular structures is more difficult and intolerable, and carries a high potential for excessive hemorrhage in patients with an extremely narrow spinal canal. Different surgical techniques for fusion of the lumbar spine have evolved over the years, but there is no definite evidence indicating which surgical strategy is better than the others (9). In our institute, 3 methods for achieving lumbar fusion from a posterior approach, including TLIF, PLIF, and PLF, are used based on the preference of the surgeons. TLIF was accepted most commonly and performed in more than half of our patients (57.3%). In theory, the advantages of the TLIF procedure are mainly the limiting of possible nerve injury and decreasing the risk of a durotomy when placing a graft along the weight-bearing axis of the vertebral body (10); however, we found that the frequency of significant blood loss was greater in patients who underwent TLIF. A recent prospective randomized clinical study analyzed the complications and outcomes of 100 patients treated with TLIF or instrumented PLF with a 2-year follow-up period (11). The study found that both groups showed improvement in functional outcome, back pain, and leg pain, but operation time and blood
REFERENCES 1. American Society of Anesthesiologists: ASA Physical Status Classification System. Available at: http:// www.asahq.org/resources/clinical-information/asaphysical-status-classification-system. Accessed Jan 18, 2014. 2. Camillo FX: Arthrodesis of the spine. In: Canale ST, Beaty JH, eds. Campbell’s Operative Orthopaedics. 11th ed. Philadelphia, PA: Mosby; 2007:1851-1874. 3. Carson JL, Poses RM, Spence RK, Bonavita G: Severity of anaemia and operative mortality and morbidity. Lancet 1:727-729, 1988. 4. Christensen A, Hoy K, Bunger C, Helmig P, Hansen ES, Andersen T, Sogaard R: Transforaminal lumbar interbody fusion vs. posterolateral instrumented fusion: cost-utility evaluation along side an RCT with a 2-year follow-up. Eur Spine J 23:1137-1143, 2014. 5. De Keulenaer BL, De Waele JJ, Powell B, Malbrain ML: What is normal intra-abdominal pressure and how is it affected by positioning, body mass and positive end-expiratory pressure? Intensive Care Med 35:969-976, 2009.
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loss were significantly greater with the TLIF procedure. Another research presented there was no convincing advantage to TLIF in either cost or effect (4). Our results were compatible with the operative findings of the aforementioned studies, and we considered complex procedures may be responsible for more surgical blood loss. Although the TLIF technique has been used commonly worldwide, a larger well-designed clinical trial is needed to clarify the complications and establish the superiority of diverse surgical techniques for lumbar fusion. This study has several potential limitations. It was a retrospective review of preexisting data and suffers from the inherent limitations of such studies. Data collection through chart reviews is less complete and less accurate than planned research. From a statistical standpoint, the number of patients was still relatively small, and the study may be underpowered to detect the significance of some risk factors. In addition, the findings reflect the experience of a single large urban medical center; hence, the results may not be representative of all patients undergoing lumbar fusion in other institutes. Even with these issues, we consider that these data provide valuable information for preoperative assessment and possible avenues for disease or procedure modification. CONCLUSIONS BMI, spine fusion segments >1 level, extreme spinal canal narrowing, and TLIF are independent risk factors for significant blood loss in patients undergoing lumbar fusion surgery for degeneration. Because substantial bleeding in lumbar fusion is associated with a greater incidence of morbidities and prolonged hospital stay, attention to these risk factors is important in preoperative assessment and postoperative guidance for the level of care.
6. Duke M, Abelmann WH: The hemodynamic response to chronic anemia. Circulation 39: 503-515, 1969.
12. Izaks GJ, Westendorp RG, Knook DL: The definition of anemia in older persons. JAMA 281: 1714-1717, 1999.
7. Elgafy H, Bransford RJ, McGuire RA, Dettori JR, Fischer D: Blood loss in major spine surgery: are there effective measures to decrease massive hemorrhage in major spine fusion surgery? Spine (Phila Pa 1976) 35:S47-S56, 2010.
13. Lee TC, Yang LC, Chen HJ: Effect of patient position and hypotensive anesthesia on inferior vena caval pressure. Spine (Phila Pa 1976) 23:941-947; discussion 947-948, 1998.
8. Flegal KM, Carroll MD, Kit BK, Ogden CL: Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010. JAMA 307:491-497, 2012. 9. Gibson JN, Waddell G: Surgery for degenerative lumbar spondylosis: updated Cochrane Review. Spine (Phila Pa 1976) 30:2312-2320, 2005. 10. Harms J, Rolinger H: A one-stager procedure in operative treatment of spondylolistheses: dorsal traction-reposition and anterior fusion (author’s transl). Z Orthop Ihre Grenzgeb 120:343-347, 1982. 11. Hoy K, Bunger C, Niederman B, Helmig P, Hansen ES, Li H, Andersen T: Transforaminal lumbar interbody fusion (TLIF) versus posterolateral instrumented fusion (PLF) in degenerative lumbar disorders: a randomized clinical trial with 2-year follow-up. Eur Spine J 22:2022-2029, 2013.
14. Lenoir B, Merckx P, Paugam-Burtz C, Dauzac C, Agostini MM, Guigui P, Mantz J: Individual probability of allogeneic erythrocyte transfusion in elective spine surgery: the predictive model of transfusion in spine surgery. Anesthesiology 110: 1050-1060, 2009. 15. Nuttall GA, Horlocker TT, Santrach PJ, Oliver WC Jr, Dekutoski MB, Bryant S: Predictors of blood transfusions in spinal instrumentation and fusion surgery. Spine (Phila Pa 1976) 25: 596-601, 2000. 16. Owens RK 2nd, Crawford CH 3rd, Djurasovic M, Canan CE, Burke LO, Bratcher KR, McCarthy KJ, Carreon LY: Predictive factors for the use of autologous cell saver transfusion in lumbar spinal surgery. Spine (Phila Pa 1976) 38:E217-E222, 2013. 17. Rajaee SS, Bae HW, Kanim LE, Delamarter RB: Spinal fusion in the United States: analysis of trends from 1998 to 2008. Spine (Phila Pa 1976) 37: 67-76, 2012.
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ORIGINAL ARTICLE YU-HUA HUANG AND CHIEN-YU OU
BLOOD LOSS IN LUMBAR FUSION FOR DEGENERATIVE SPINE
18. Schizas C, Theumann N, Burn A, Tansey R, Wardlaw D, Smith FW, Kulik G: Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images. Spine (Phila Pa 1976) 35: 1919-1924, 2010.
22. Wu WC, Smith TS, Henderson WG, Eaton CB, Poses RM, Uttley G, Mor V, Sharma SC, Vezeridis M, Khuri SF, Friedmann PD: Operative blood loss, blood transfusion, and 30-day mortality in older patients after major noncardiac surgery. Ann Surg 252:11-17, 2010.
19. Schonauer C, Bocchetti A, Barbagallo G, Albanese V, Moraci A: Positioning on surgical table. Eur Spine J 13 (Suppl 1):S50-S55, 2004.
23. Wu WC, Trivedi A, Friedmann PD, Henderson WG, Smith TS, Poses RM, Uttley G, Vezeridis M, Eaton CB, Mor V: Association between hospital intraoperative blood transfusion practices for surgical blood loss and hospital surgical mortality rates. Ann Surg 255:708-714, 2012.
20. Segal JB, Guallar E, Powe NR: Autologous blood transfusion in the United States: clinical and nonclinical determinants of use. Transfusion 41: 1539-1547, 2001. 21. Shamji MF, Parker S, Cook C, Pietrobon R, Brown C, Isaacs RE: Impact of body habitus on perioperative morbidity associated with fusion of the thoracolumbar and lumbar spine. Neurosurgery 65:490-498; discussion 498, 2009.
24. Yoshihara H, Yoneoka D: Predictors of allogeneic blood transfusion in spinal fusion in the United States, 2004-2009. Spine (Phila Pa 1976) 39: 304-310, 2014. 25. Zheng F, Cammisa FP Jr, Sandhu HS, Girardi FP, Khan SN: Factors predicting hospital stay, oper-
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ative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation. Spine (Phila Pa 1976) 27:818-824, 2002.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 3 April 2015; accepted 6 May 2015 Citation: World Neurosurg. (2015) 84, 3:780-785. http://dx.doi.org/10.1016/j.wneu.2015.05.007 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
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785
Significant Blood Loss in Lumbar Fusion Surgery for Degenerative Spine Yu-Hua Huang1,2 and Chien-Yu Ou1,3
OBJECTIVE: Lumbar fusion is a widely used procedure for degenerative spine diseases but frequently is accompanied with substantial surgical blood loss. We aimed to investigate the risk factors for significant intraoperative blood loss and the influence of excessive bleeding on postoperative complications in patients undergoing fusion for degenerative lumbar spines.
-
METHODS: For this retrospective study, we enrolled 199 patients who had undergone lumbar fusion surgery for degeneration. The definition of significant blood loss at operation was 500 mL or more in blood volume. The patients were subdivided into 2 groups on the basis of whether significant blood loss was present (n [ 107) or not (n [ 92).
-
RESULTS: The incidence of significant blood loss during lumbar fusion was 53.8%. In the multivariate logistic regression model, the independent risk factors for significant blood loss included body mass index (P [ 0.027), extreme spinal canal narrowing (P [ 0.023), spine fusion segments >1 level (P [ 0.008), and transforaminal lumbar interbody fusion (P [ 0.006). Significant blood loss in lumbar fusion was associated with a greater incidence of postoperative complications (P [ 0.002). The length of hospital stay for patents with excessive bleeding was prolonged significantly (P [ 0.045).
-
CONCLUSIONS: Because substantial bleeding in lumbar fusion is associated with a greater incidence of morbidities and prolonged length of hospital stay, attention to the risk factors for significant blood loss is important in the preoperative assessment and postoperative guidance for the level of care.
-
INTRODUCTION
A
s early as 1911, Hibbs and Albee described fusion surgery of the spine that aimed to stabilize diseased vertebrae by using bone grafts (2). Since then, fusion surgery has become a widely used therapy for various spinal conditions, and one of the common indications is degenerative lumbar spine diseases (17). Although this procedure is technically familiar to surgeons, it is not without morbidities. Spinal fusion is accompanied frequently by substantial blood loss and is among the top surgical procedures associated with blood transfusion (20). Significant intraoperative blood loss of 500 mL or greater, which increases postoperative morbidity and mortality in patients undergoing major noncardiac surgery, has been reported (3, 22, 23). In addition, fusion of degenerative lumbar spines usually is carried out among geriatric patients. Older patients are especially vulnerable to the detrimental effects of blood loss and anemia because of the limited physiological reserve (6, 12). Blood loss during surgery also leads to the need of red cell, platelets, or factor transfusions, and the potential for immunological reaction and infection transmission must be considered. As a result, the ability to identify the risk of significant blood loss in patients undergoing lumbar fusion procedures is quite important and may guide the level of care and offer modifiable targets to alleviate the effect of morbidities. In this study, we retrospectively collected clinical data and assessed risk factors for significant blood loss during lumbar fusion surgery for degenerative spine diseases. We also investigated the impact of significant intraoperative blood loss on postoperative complications. MATERIALS AND METHODS Data Collection This retrospective cohort study was carried out at Kaohsiung Chang Gung Memorial Hospital, a 2715-bed medical center in
Key words - Blood loss - Complication - Degenerative spine disease - Lumbar fusion
From the 1Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; 2Department of Neurosurgery, Kaohsiung Municipal Min-Sheng Hospital, Kaohsiung, Taiwan; and 3 Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan
Abbreviations and Acronyms ASA: American Society of Anesthesiologists BMI: Body mass index CSF: Cerebrospinal fluid PLF: Posterolateral lumbar fusion PLIF: Posterior lumbar interbody fusion TLIF: Transforaminal lumbar interbody fusion
Citation: World Neurosurg. (2015) 84, 3:780-785. http://dx.doi.org/10.1016/j.wneu.2015.05.007
780
www.SCIENCEDIRECT.com
To whom correspondence should be addressed: Chien-Yu Ou, M.D. [E-mail: [email protected]]
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.05.007
ORIGINAL ARTICLE YU-HUA HUANG AND CHIEN-YU OU
Taiwan. After obtaining consent from the institutional review board, we reviewed the records of patients who had undergone lumbar fusion surgery for degenerative spine diseases in the neurosurgical department from September 2012 through June 2013. We excluded patients who had had previous spine surgeries. A total of 199 patients were enrolled for analysis. Trained research staff collected clinical data, consisting of the patients’ baseline information, body mass index (BMI), findings of laboratory examinations, and American Society of Anesthesiologists (ASA) Physical Status Classification (1). Details of the operations were recorded, and total intraoperative blood loss was calculated as the sum of blood in suction containers and soaked sponges. The definition of significant operative blood loss was 500 mL or more of blood volume (3, 22, 23). Preoperative Evaluation Diagnosis of degenerative lumbar spine disease was established on the basis of the history and physical examination in conjunction with magnetic resonance imaging scans. In addition, anteroposterior translation or intervertebral rotation was examined on lateral flexion/extension and anteroposterior radiographs. All patients experienced low back pain, lower extremity pain, or other neurologic deficits resulting from spinal stenosis or localized lumbar/lumbosacral segmental instability at the L1eS1 levels. The levels of the affected vertebrae with a compressed dura sac or nerve roots were determined. The degree of spinal canal narrowing was evaluated on the basis of the cerebrospinal fluid (CSF)/rootlet ratio as seen in axial T2 images, and was graded as A, B, C, and D (Grade A stenosis, i.e., there is clearly CSF visible inside the dural sac, but its distribution is inhomogeneous; Grade B stenosis, i.e., the rootlets occupy the whole of the dural sac, but they can still be individualized; Grade C stenosis, i.e., no rootlets can be recognized, the dural sac demonstrating a homogeneous gray signal with no CSF signal visible; Grade D stenosis, i.e., in addition to no rootlets being recognizable, there is no epidural fat posteriorly) (18). Grade D was defined as extreme spinal canal narrowing in this study. Surgical Strategy and Techniques Lumbar spine fusion was indicated when the patients had clinical and/or radiographic signs of instability or were at risk of iatrogenic instability after decompression. The patients underwent one of the following 3 fusion procedures: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), or posterolateral lumbar fusion (PLF). In brief, neural decompression was carried out by removing the degenerated ligamenta flava, lamina of vertebrae, or protruded disc. In cases involving PLIF or TLIF, the cage was placed after cleaning the disc space. For PLF, removed lamina with or without iliac bone was used as autologous bone graft and placed on the transverse process of the vertebra. Pedicle screw instrumentation was performed on the basis of the stability of the fused spines, as determined by the surgeon. There was no artificial disc replacement, corpectomy, osteotomy, kyphectomy, or insertion of spinal spacers or dynamic stabilizing devices in our patient group. Postoperative Complications The outcome for this study was postoperative complications during hospitalization. The following events were defined as
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BLOOD LOSS IN LUMBAR FUSION FOR DEGENERATIVE SPINE
complications: acute renal failure, myocardial infarction, stroke, delirium, deep venous thrombosis, pulmonary embolism, wound disruption, deep surgical-site infection, pneumonia, urinary tract infection, sepsis, systemic inflammatory response syndrome, and >4 U red blood cell transfusion within 72 hours after operation. All deaths also were considered postoperative complications. Statistical Analysis Data were analyzed using SPSS version 20.0 (IBM SPSS Statistics, Armonk, New York, USA). Descriptive statistics are presented as frequencies (percentages) or as mean and SD. Categorical variables were compared using the c2 test or Fisher exact test. Continuous variables were assessed using the Student’s t test or ManneWhitney U test. All parameters with a P < 0.05 were entered into multivariable logistic regression to adjust for independent risk factors of significant blood loss during lumbar fusion surgery. The results were expressed as odds ratios with 95% confidence intervals. A P < 0.05 was considered to be statistically significant. RESULTS Patient Characteristics The 199 patients who underwent lumbar fusion surgery for degenerative spine diseases included 90 men and 109 women. The mean age was 61.8 (SD, 12.3; range, 20e83) years. Underlying medical conditions included 40 cases of diabetes mellitus, 110 of hypertension, 6 of coronary artery disease, 1 patient receiving anticoagulant therapy, and 9 patients undergoing antiplatelet therapy. The anticoagulant and antiplatelet treatments were halted before surgery. Average BMI was 26.8 (SD, 3.6; range, 18e40) kg/m2. The mean hemoglobin level before operation was 13.2 (SD, 1.7; range, 9e19) g/dL. The number of patients with ASA classification I, II, and III was 7, 101, and 91, respectively. There were 56 patients with extreme spinal canal narrowing on the basis of findings on magnetic resonance imaging. Lumbar Fusion Surgery The mean blood loss during operation was 554.3 (SD, 346.3; range 50e1850) mL. Figure 1 shows the distribution of the volume of
Figure 1. Distribution of volume of surgical blood loss in lumbar fusion.
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surgical blood loss for the 199 patients. Significant blood loss (500 mL) was identified in 107 (53.8%) patients. There were 27 patients undergoing perioperative allogenic red cell transfusion. The mean duration of operation was 5.9 (SD, 1.9; range 2e12) hours. The spinal fusion segments were as follows: 1 level in 113 patients, 2 levels in 69 patients, 3 levels in 16 patients, and 4 levels in 1 patient. Thirty-nine and 114 patients underwent PLIF and TLIF, respectively; PLF was performed in 46 patients. In all, 164 patients had pedicle screw instrumentation. Risk Factors for Significant Intraoperative Blood Loss In a comparison of clinical features of patients with or without significant blood loss, statistical analysis identified the following parameters with a P < 0.05: age (P ¼ 0.006), diabetes mellitus (P ¼ 0.021), BMI (P < 0.001), preoperative hemoglobin (P ¼ 0.004), ASA classification (P ¼ 0.004), extreme spinal canal
narrowing (P < 0.001), spine fusion segments >1 level (P < 0.001), TLIF (P ¼ 0.012), and duration of operation (P ¼ 0.009) (Table 1). All of these factors were entered into multivariable regression analysis, and the independent risk factors for significant blood loss in lumbar fusion included BMI (P ¼ 0.027), extreme spinal canal narrowing (P ¼ 0.023), spine fusion segments >1 level (P ¼ 0.008), and TLIF (P ¼ 0.006) (Table 2). We further stratified the patients into 3 subgroups on the basis of BMI (normal weight: BMI 1 level
2.78 (1.31e5.89)
0.008
TLIF
2.97 (1.37e6.43)
0.006
Duration of operation
1.23 (0.99e1.51)
0.057
CI, confidence interval; ASA classification, American Society of Anesthesiologists Physical Status Classification; TLIF, transforaminal lumbar interbody fusion. Values in bold indicate statistical significance.
delirium, 1 of wound disruption, 2 of deep surgical-site infection, 4 of pneumonia, 11 of urinary tract infection, 2 of systemic inflammatory response syndrome, and 2 red cell transfusions >4 U. There was no in-hospital mortality. The patients were subdivided into 2 groups on the basis of whether significant blood loss was present, and the intergroup differences in the observed rates of complications were statistically significant (P ¼ 0.002). The mean duration of hospital stay was 9.8 (SD 4.9) and 8.6 (SD 3.1) days for patients with and without significant blood loss, respectively (P ¼ 0.045) (Table 1).
Figure 2. Box plot for surgical blood loss in lumbar fusion using body mass index (BMI) stratification.
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DISCUSSION Lumbar fusion for degenerative spine disease is among the most common surgical procedures and has an increasing frequency annually (17). With more and more attention being paid to patient safety, the problems with this procedure are under closer investigation. In this study, the rate of significant blood loss was 53.8%, which was comparable with the abundant intraoperative hemorrhage of spinal fusion in the literature (7). Rates of mortality and morbidity were reported to be related to blood loss during surgery, increasing prominently for patients who lost more than 500 mL (3). In contrast, an increase in the rate of intraoperative blood transfusion accompanied a decrease in postoperative mortality for this high-risk population (23). Our results also confirmed that significant blood loss in lumbar fusion was associated with a greater incidence of postoperative complications. As expected, the length of hospital stay for patients with substantial bleeding was prolonged concomitantly. An increased understanding of the risks of significant blood loss is pivotal to improving surgical outcomes. In addition, careful patient assessment offers an opportunity to control medical costs. Several predictive factors of blood transfusion requirements in patients undergoing spine fusion, such as female sex, age, low preoperative hemoglobin, high comorbidity score, number of fused vertebrae, or surgical approach, have been documented (15, 24). However, the delivery of blood transfusion depends not only on the blood loss amount but also on multiple determinants, including those of patients, surgeons, or anesthesiologists, and a large variation exists in hospitals’ practices for patients with significant surgical blood loss (23). Therefore, calculating the volume of blood loss and evaluating the parameters related to surgical bleeding can be more direct and practical for risk identification. In this series, we demonstrated the 4 independent risk factors for significant blood loss in lumbar fusion, including BMI, longsegment spinal fusion, extreme spinal canal narrowing, and TLIF. In a study of 112 patients undergoing revision lumbar spine surgery, Zheng et al. (25) reported body weight was one of the factors predicting intraoperative blood loss. Shamji et al. (21) found that obese and morbidly obese patients had increased transfusion requirements during thoracolumbar and lumbar spine fusion, independent of the surgical approach used. Our results consistently showed BMI was a significant variable in multivariable logistic regression, and the difference in the average volume of surgical blood loss between patients with normal weight and obese patients was up to 227 mL (P ¼ 0.008). One reasonable explanation for excessive bleeding may be the relationship between obesity and intra-abdominal pressure. Reducing intra-abdominal pressure, which in turn lowers vertebral venous pressure, is a documented method for controlling blood loss during lumbar spine surgery (13, 19). However, a greater baseline level of intra-abdominal pressure was observed in obese patients (5). Besides, a direct compressive effect from the abdominal adipose tissue when in a prone position also may affect intra-abdominal pressure and result in an increase of blood loss from epidural veins. A greater number of fused vertebrae is an established risk factor for blood transfusion in spinal surgery (14, 16, 24). It is not surprising that our results support the greater incidence of significant
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blood loss in lumbar fusion of more than 1 level. Long-segment fusion needs extensive exposure of the spine, which means extensive muscle and soft-tissue detaching from the vertebrae. The more raw surfaces of muscle and bone are exposed, the more blood will be lost. Also, extreme spinal canal narrowing is a factor associated with substantial bleeding, and we found that it carried a 2.8-fold greater risk of significant blood loss in lumbar fusion. Severe compression of the spinal canal probably results in tenuous blood return and subsequent engorgement of epidural veins. In addition, increased epidural adhesion may be accompanied with an advanced degeneration course. Therefore, manipulation or coagulation of vascular structures is more difficult and intolerable, and carries a high potential for excessive hemorrhage in patients with an extremely narrow spinal canal. Different surgical techniques for fusion of the lumbar spine have evolved over the years, but there is no definite evidence indicating which surgical strategy is better than the others (9). In our institute, 3 methods for achieving lumbar fusion from a posterior approach, including TLIF, PLIF, and PLF, are used based on the preference of the surgeons. TLIF was accepted most commonly and performed in more than half of our patients (57.3%). In theory, the advantages of the TLIF procedure are mainly the limiting of possible nerve injury and decreasing the risk of a durotomy when placing a graft along the weight-bearing axis of the vertebral body (10); however, we found that the frequency of significant blood loss was greater in patients who underwent TLIF. A recent prospective randomized clinical study analyzed the complications and outcomes of 100 patients treated with TLIF or instrumented PLF with a 2-year follow-up period (11). The study found that both groups showed improvement in functional outcome, back pain, and leg pain, but operation time and blood
REFERENCES 1. American Society of Anesthesiologists: ASA Physical Status Classification System. Available at: http:// www.asahq.org/resources/clinical-information/asaphysical-status-classification-system. Accessed Jan 18, 2014. 2. Camillo FX: Arthrodesis of the spine. In: Canale ST, Beaty JH, eds. Campbell’s Operative Orthopaedics. 11th ed. Philadelphia, PA: Mosby; 2007:1851-1874. 3. Carson JL, Poses RM, Spence RK, Bonavita G: Severity of anaemia and operative mortality and morbidity. Lancet 1:727-729, 1988. 4. Christensen A, Hoy K, Bunger C, Helmig P, Hansen ES, Andersen T, Sogaard R: Transforaminal lumbar interbody fusion vs. posterolateral instrumented fusion: cost-utility evaluation along side an RCT with a 2-year follow-up. Eur Spine J 23:1137-1143, 2014. 5. De Keulenaer BL, De Waele JJ, Powell B, Malbrain ML: What is normal intra-abdominal pressure and how is it affected by positioning, body mass and positive end-expiratory pressure? Intensive Care Med 35:969-976, 2009.
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loss were significantly greater with the TLIF procedure. Another research presented there was no convincing advantage to TLIF in either cost or effect (4). Our results were compatible with the operative findings of the aforementioned studies, and we considered complex procedures may be responsible for more surgical blood loss. Although the TLIF technique has been used commonly worldwide, a larger well-designed clinical trial is needed to clarify the complications and establish the superiority of diverse surgical techniques for lumbar fusion. This study has several potential limitations. It was a retrospective review of preexisting data and suffers from the inherent limitations of such studies. Data collection through chart reviews is less complete and less accurate than planned research. From a statistical standpoint, the number of patients was still relatively small, and the study may be underpowered to detect the significance of some risk factors. In addition, the findings reflect the experience of a single large urban medical center; hence, the results may not be representative of all patients undergoing lumbar fusion in other institutes. Even with these issues, we consider that these data provide valuable information for preoperative assessment and possible avenues for disease or procedure modification. CONCLUSIONS BMI, spine fusion segments >1 level, extreme spinal canal narrowing, and TLIF are independent risk factors for significant blood loss in patients undergoing lumbar fusion surgery for degeneration. Because substantial bleeding in lumbar fusion is associated with a greater incidence of morbidities and prolonged hospital stay, attention to these risk factors is important in preoperative assessment and postoperative guidance for the level of care.
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8. Flegal KM, Carroll MD, Kit BK, Ogden CL: Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010. JAMA 307:491-497, 2012. 9. Gibson JN, Waddell G: Surgery for degenerative lumbar spondylosis: updated Cochrane Review. Spine (Phila Pa 1976) 30:2312-2320, 2005. 10. Harms J, Rolinger H: A one-stager procedure in operative treatment of spondylolistheses: dorsal traction-reposition and anterior fusion (author’s transl). Z Orthop Ihre Grenzgeb 120:343-347, 1982. 11. Hoy K, Bunger C, Niederman B, Helmig P, Hansen ES, Li H, Andersen T: Transforaminal lumbar interbody fusion (TLIF) versus posterolateral instrumented fusion (PLF) in degenerative lumbar disorders: a randomized clinical trial with 2-year follow-up. Eur Spine J 22:2022-2029, 2013.
14. Lenoir B, Merckx P, Paugam-Burtz C, Dauzac C, Agostini MM, Guigui P, Mantz J: Individual probability of allogeneic erythrocyte transfusion in elective spine surgery: the predictive model of transfusion in spine surgery. Anesthesiology 110: 1050-1060, 2009. 15. Nuttall GA, Horlocker TT, Santrach PJ, Oliver WC Jr, Dekutoski MB, Bryant S: Predictors of blood transfusions in spinal instrumentation and fusion surgery. Spine (Phila Pa 1976) 25: 596-601, 2000. 16. Owens RK 2nd, Crawford CH 3rd, Djurasovic M, Canan CE, Burke LO, Bratcher KR, McCarthy KJ, Carreon LY: Predictive factors for the use of autologous cell saver transfusion in lumbar spinal surgery. Spine (Phila Pa 1976) 38:E217-E222, 2013. 17. Rajaee SS, Bae HW, Kanim LE, Delamarter RB: Spinal fusion in the United States: analysis of trends from 1998 to 2008. Spine (Phila Pa 1976) 37: 67-76, 2012.
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18. Schizas C, Theumann N, Burn A, Tansey R, Wardlaw D, Smith FW, Kulik G: Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images. Spine (Phila Pa 1976) 35: 1919-1924, 2010.
22. Wu WC, Smith TS, Henderson WG, Eaton CB, Poses RM, Uttley G, Mor V, Sharma SC, Vezeridis M, Khuri SF, Friedmann PD: Operative blood loss, blood transfusion, and 30-day mortality in older patients after major noncardiac surgery. Ann Surg 252:11-17, 2010.
19. Schonauer C, Bocchetti A, Barbagallo G, Albanese V, Moraci A: Positioning on surgical table. Eur Spine J 13 (Suppl 1):S50-S55, 2004.
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 3 April 2015; accepted 6 May 2015 Citation: World Neurosurg. (2015) 84, 3:780-785. http://dx.doi.org/10.1016/j.wneu.2015.05.007 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
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