Chronic Antiplatelet Use Associated With Increased Blood Loss in Lumbar Spinal Surgery Despite Adherence to Protocols.

There are conflicting reports regarding postoperative bleeding risks associated with discontinuation of antiplatelet therapy at least 7 days preoperatively. Most of the studies in the spine literature are based on surveys or anecdotal evidence. The majority of surgeons discontinue therapy 7 days preoperatively, but this varies widely from 5 to 21 days. The purpose of this retrospective study was to assess whether chronic antiplatelet use is associated with increased intraoperative blood loss, need for transfusion, and perioperative complications. Of 454 patients who underwent elective lumbar spinal surgery, 85 were on antiplatelet therapy and 369 were not. All patients stopped antiplatelet therapy at least 7 days preoperatively with approval from their cardiologist or primary care provider. Multiple regression analysis was performed and corrected for age, sex, antiplatelet therapy, number of levels decompressed/fused/instrumented, preoperative hematocrit, and postoperative hematocrit. Results showed that preoperative antiplatelet therapy, despite at least 7 days of discontinuation, is a statistically significant predictor (P=.04) of increased intraoperative blood loss. Blood transfusion was not associated with antiplatelet use but was associated with the number of levels fused, age, and low preoperative hematocrit (all P<.01). There were no recorded complications in either group. The authors conclude that antiplatelet therapy is associated with an increased risk of intraoperative blood loss in spine patients despite discontinuation at least 7 days preoperatively, but the clinical significance of this is unclear given the lack of association with blood transfusions and perioperative complications. [Orthopedics. 2016; 39(4):e695-e700.].

Smoking is Associated with Increased Blood Loss and Transfusion Use After Lumbar Spinal Surgery.

BACKGROUND: Little is known about the association between smoking and intraoperative blood loss and perioperative transfusion use in patients undergoing spinal surgery. However, we found that although many of the common complications and deleterious effects of smoking on surgical patients had been well documented, the aspect of blood loss seemingly had been overlooked despite data reported in nonorthopaedic sources to suggest a possible connection. QUESTIONS/PURPOSES: We asked: (1) Is smoking associated with increased estimated blood loss during surgery in patients undergoing lumbar spine surgery? (2) Is smoking associated with increased perioperative transfusion usage? METHODS: Between 2005 and 2009, 581 lumbar decompression procedures (with or without fusion) were performed at one academic spine center. Of those, 559 (96%) had sufficient chart documentation to categorize patients by smoking status, necessary intra- and postoperative data to allow analysis with respect to bleeding and transfusion-related endpoints, and who did not meet exclusion criteria. Exclusion criteria included: patients whose smoking status did not fit in our two categories, patients with underlying coagulopathy, patients receiving anticoagulants (including aspirin and platelet inhibitors), history of hepatic disease, history of platelet disorder or other blood dyscrasias, and patient or family history of any other known bleeding disorder. Smoking history in packs per day was obtained for all subjects. We defined someone as a smoker if the patient reported smoking up until the day of their surgical procedure; nonsmokers were patients who quit smoking at least 6 weeks before surgery or had no history of smoking. We used a binomial grouping for whether patients did or did not receive a transfusion perioperatively. Age, sex, number of levels of discectomies, number of levels decompressed, number of levels fused, and use of instrumentation were recorded. The same approaches were used for transfusions in all patients regardless of smoking history; decisions were made in consultation between the surgeon and the anesthesia team. Absolute indications for transfusion postoperatively were: a hemoglobin less than 7 g/dL, continued symptoms of dizziness, tachycardia, decreased exertional tolerance, or hypotension that failed to respond to fluid resuscitation. Multiple linear regression analyses correcting for the above variables were performed to determine associations with intraoperative blood loss, while logistic regression was used to analyze perioperative transfusion use. RESULTS: After controlling for potentially relevant confounding variables noted earlier, we found smokers had increased estimated blood loss compared with nonsmokers (mean, 328 mL more for each pack per day smoked; 95% CI, 249-407 mL; p < 0.001). We also found that again correcting for confounders, smokers had increased perioperative transfusion use compared with nonsmokers (odds ratio, 13.8; 95% CI, 4.59-42.52). CONCLUSIONS: Smoking is associated with increased estimated surgical blood loss and transfusion use in patients undergoing lumbar spine surgery. Patients who smoke should be counseled regarding these risks and on smoking cessation before undergoing lumbar surgery. LEVEL OF EVIDENCE: Level III, therapeutic study.

Development of an Experimental Animal Model for Lower Back Pain by Percutaneous Injury-Induced Lumbar Facet Joint Osteoarthritis.

We report generation and characterization of pain-related behavior in a minimally invasive facet joint degeneration (FJD) animal model in rats. FJD was produced by a non-open percutaneous puncture-induced injury on the right lumbar FJs at three consecutive levels. Pressure hyperalgesia in the lower back was assessed by measuring the vocalization response to pressure from a force transducer. After hyperalgesia was established, pathological changes in lumbar FJs and alterations of intervertebral foramen size were assessed by histological and imaging analyses. To investigate treatment options for lumber FJ osteoarthritis-induced pain, animals with established hyperalgesia were administered with analgesic drugs, such as morphine, a selective COX-2 inhibitor, a non-steroidal anti-inflammatory drug (NSAID) (ketorolac), or pregabalin. Effects were assessed by behavioral pain responses. One week after percutaneous puncture-induced injury of the lumbar FJs, ipsilateral primary pressure hyperalgesia developed and was maintained for at least 12 weeks without foraminal stenosis. Animals showed decreased spontaneous activity, but no secondary hyperalgesia in the hind paws. Histopathological and microfocus X-ray computed tomography analyses demonstrated that the percutaneous puncture injury resulted in osteoarthritis-like structural changes in the FJs cartilage and subchondral bone. Pressure hyperalgesia was completely reversed by morphine. The administration of celecoxib produced moderate pain reduction with no statistical significance while the administration of ketorolac and pregabalin produced no analgesic effect on FJ osteoarthritis-induced back pain. Our animal model of non-open percutanous puncture-induced injury of the lumbar FJs in rats shows similar characteristics of low back pain produced by human facet arthropathy.

Fusion in degenerative spondylolisthesis: comparison of osteoconductive and osteoinductive bone graft substitutes.

INTRODUCTION: The emergent widespread options of bone graft substitutes for spinal fusion procedures vary in their osteobiologic activity. A majority of current literature focuses on the comparison of osteoinductive (OI) or osteoconductive (OC) bone graft substitutes individually against ICBG. These studies have demonstrated the legitimacy of bone graft substitutes, but despite the widespread use in spinal fusion procedures there is a dearth in the current literature in the direct comparison of OC and OI substitutes. This retrospective comparative analysis compares the efficacy of OI vs. solely OC agents in producing radiographic fusion on patients with DS. METHODS: Patients, who underwent a lumbar fusion for DS with at least 6 months post-op radiographs, were divided based on whether they received an OC or OI bone graft substitute. The OC groups included allografts, calcium phosphate, ceramics and hydroxyapatite products. The OI group included bone morphogenic protein, demineralized bone matrix, and stem cell-based products. MEASUREMENT CRITERIA: Using a conservative hierarchical approach to determine fusion, fusion criteria included stringent use of multiple measurement methods including flexion/extension x-rays, Lenke and Brantigan CT fusion measurement criteria, and history of revision surgery due to pseudoarthrosis. RESULTS: A total of 126 patients (78 OI, 48 OC) met the studies inclusion criteria for the assessment for fusion. The mean time for flexion-extension radiographic evaluation was 13.1 months for the OI group and 15 months for the OC group. The mean time for CT scan evaluation was 18 months for the OI group and 15.9 months for the OC group. Using the stated hierarchical criteria for fusion stated above, the fusion rate for the OI group was 87.18%, and the fusion rate for the OC group was 93.75%. The difference in OI and OC groups was not statistically significant (P = 0.367). Based on the demographic data collected, there were no statistically significant factors determining fusion. CONCLUSION: With the vastly growing market for OI and OC materials commonly used in lumbar spinal fusions, the options for surgical treatment for degenerative spondylolisthesis are ever expanding. No significant difference was found when comparing fusion rates between the two types of materials in this retrospective analysis. Interestingly, TLIF procedures provided lower fusion rates than posterolateral fusion procedures. This may be due to a small sample size but the association with a minimally invasive technique warrants investigation. Due to the substantial difference in price between the OI and OC materials and the lack of evidence supporting higher fusion rates with more expensive OI agents, it is incumbent on the spine community to consider and reassess the products that are routinely used.

Trends in musculoskeletal imaging in trauma patients: how has our practice changed over time?

OBJECTIVES: The purpose of the study was to review diagnostic imaging in trauma patients. We hypothesized that diagnostic musculoskeletal imaging has increased over time, but at a lesser rate than radiography performed for other purposes. Two trauma centers were compared. DESIGN: Retrospective multicenter study. SETTING: Two level 1 trauma centers. PATIENTS/PARTICIPANTS: Five hundred patients per year from each trauma centers were reviewed for 2002, 2005, and 2008. MAIN OUTCOME MEASUREMENTS: Effective doses [millisieverts (mSv)] and total charges for radiography were calculated. RESULTS: Most imaging was performed within 24 hours of injury. In 2002, 15% of all radiographic studies were computed tomography (CT) scans compared with 33% in 2008 (P < 0.0001). Center 1 used more CT, and center 2 used more projection (plain) radiography. The percentage of musculoskeletal CTs increased from 26% in 2002 to 49% in 2008 (P < 0.0001), without change in patient acuity. The mean effective dose per patient was 17.3 mSv in 2002, 30.0 mSv in 2005, and 34.1 mSv in 2008 (P < 0.001). The percentage of total dose attributable to musculoskeletal studies increased from 25% in 2002, to 29% in 2005, and 31% in 2008 (P < 0.001). Mean total charges per patient were $4529 in 2002; $6922 in 2005; and $7750 in 2008 (P < 0.001), with higher 2008 mean charges at center 1 versus 2 ($8694 vs. $6806, P = 0.001), primarily because of more CT scans. CONCLUSIONS: The number of diagnostic imaging tests, radiation dose, and related charges in trauma patients increased over time at both trauma centers, with CT scans accounting for most of the radiation dose and costs. A shift toward more advanced imaging from conventional projection radiography was noted at both trauma centers. Effective dose per patient more than doubled over the course of study at center 1. By 2008, half of all radiographic studies were for musculoskeletal purposes. Previous studies have suggested an increased risk of cancer with exposures of 20-40 mSv, making the mean total radiation doses in excess of 30.0 mSv since 2005 of great concern. Variability in ordering patterns between the 2 centers with similar patient acuity suggests opportunity for discussion about indications for utilization, which could result in lower radiation doses and fewer expenses.

Complications of spinal fusion with utilization of bone morphogenetic protein: a systematic review of the literature.

STUDY DESIGN: Systematic review. OBJECTIVE: A systematic review was performed to identify the types of complications and complication rates associated with the use of bone morphogenetic protein (BMP) in both anterior and posterior cervical and lumbar spine surgery. SUMMARY OF BACKGROUND DATA: There has been an increase in BMP use in various clinical situations typically in an "off-label" fashion. Associated with its use, however, have been reports of various complications. METHODS: A MEDLINE search was conducted. All articles involving complications after spine surgery in patients receiving BMP were included. Articles were excluded on the basis of the following criteria: Non-English manuscripts and nonhuman subjects. A total of 29 articles met the inclusion and exclusion criteria and were used in the analysis. For each complication identified, the incidence was calculated by pooling the subjects from the studies that reported the complication. χ tests were used to compare the incidence rates between those that had received BMP and the control groups. RESULTS: Of the 29 articles included, 7 reported complication rates in anterior cervical fusions, 3 in posterior cervical fusions, 4 in anterior lumbar interbody fusions (ALIF), 9 in posterior/transforaminal lumbar interbody fusions (PLIF/TLIF), and 6 in posterolateral lumbar fusions. Individual complication rates when BMP was used was in the range from 0.66% to 20.1% in anterior cervical fusions, 3.5% to 14.6% in posterior cervical fusions, 2.0% to 7.3% in ALIFs, 1.5% to 21.8% in PLIF/TLIFs, and 1.4% to 8.2% in posterolateral lumbar fusions. Pseudarthrosis rates were statistically significantly lower with the utilization of BMP in all procedures except for PLIF/TLIFs, which only approached significance (P = 0.07). The only individual complication that was statistically significantly greater with BMP utilization was retrograde ejaculation in ALIFs (7.3 vs. 2.3%; P = 0.03). The rate of dysphagia/swelling in anterior cervical fusions was greater with BMP (20.1 vs. 15.6%), however this only approached statistical significance (P = 0.07). CONCLUSION: The body of literature reports complication rates with BMP ranging from 0.66% to 21.8%. However, the only statistically significant adverse complication rate was retrograde ejaculation in the ALIF population (7.3%). Despite the increased awareness of complications associated with BMP, complication rates remain spine site specific and low. Thorough patient education should be done with the physician to make an informative use regarding BMP utilization in spinal surgery. LEVEL OF EVIDENCE: 3.

Does chronic warfarin cause increased blood loss and transfusion during lumbar spinal surgery?

BACKGROUND CONTEXT: The use of oral anticoagulation therapy such as warfarin is projected to increase significantly as the population ages and the prevalence of cardiovascular disease increases. Current recommendations state that warfarin be discontinued before surgery and the international normalized ratio (INR) normalized. PURPOSE: To determine if stopping warfarin 7 days before surgery and correcting INR had any effect on intraoperative blood loss or the requirements for blood product transfusion. STUDY DESIGN/SETTING: This was a retrospective cohort study in a high-volume tertiary care center. PATIENT SAMPLE: Sample comprised 263 consecutive patients who underwent elective lumbar spinal surgery. OUTCOME MEASURE: The outcome measures were intraoperative blood loss, intraoperative blood transfusion, postoperative blood transfusion, and the number of blood products transfused. METHODS: The records of patients undergoing elective spinal surgery were analyzed for patient demographic data, comorbidities, coagulation panel laboratory findings, operative characteristics, blood loss, and blood transfusion requirements. These included patients undergoing full laminectomies with or without posterolateral fusion and instrumentation. Patients on warfarin were analyzed for the mean dosage of warfarin and underlying pathology that required anticoagulation. All patients on warfarin had their anticoagulation therapy stopped 7 days before surgery and their INR checked preoperatively to confirm normalization. Both univariate and multiple linear regression analyses were performed. RESULTS: The patients on warfarin had a mean intraoperative blood loss of 839 mL compared with 441 mL for patients not on warfarin (p<.01). Multiple regression analysis determined that warfarin and number of spinal levels decompressed/fused/instrumented were predictors for increased blood loss (R(2)=0.37). Patients on warfarin also had increased postoperative blood transfusions (23.1% compared with 7.4%, p=.04). There was no significant difference between groups in terms of intraoperative blood transfusion or number of units transfused. CONCLUSIONS: Patients on chronic anticoagulation therapy with warfarin who have their therapy stopped 7 days before surgery and have their INR normalized still demonstrated increased intraoperative blood loss and requirement for postoperative transfusion. Surgeons should be aware of the increased propensity of these patients to bleed despite adherence to protocols and should attempt to mitigate this risk.

Incidence and mortality of cardiac events in lumbar spine surgery.

STUDY DESIGN: Retrospective national database analysis. OBJECTIVE: A population-based database was analyzed to characterize the incidence, mortality, and associated risk factors for cardiac events in lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Cardiac events are a leading cause of perioperative mortality in spinal surgery. The incidence of these complications after lumbar surgery is not well characterized on a national level. METHODS: Data from the Nationwide Inpatient Sample was obtained from 2002 to 2009. Patients undergoing lumbar decompression or lumbar fusion for degenerative etiologies were identified. Patient demographics, incidence of cardiac complications, comorbidities, and mortality were assessed. Statistical analysis was performed using Student t test for discrete variables and χ test for categorical data. Logistic regression was used to identify independent predictors for cardiac complications. RESULTS: A total of 578,457 lumbar spine procedures were identified in the Nationwide Inpatient Sample from 2002 to 2009. The overall incidence of cardiac complications was 6.7 per 1000 cases. Cardiac events occurred more frequently in the lumbar fusion group, with a rate of 9.3 per 1000 cases, than in the lumbar decompression group, with a rate of 4.0 per 1000 (P < 0.0005). Patients with cardiac events were significantly older than patients without complications by 9.4 years (P < 0.0005). Patients with cardiac complications had statistically increased hospitalizations, costs, and mortality when a cardiac event was present (P < 0.0005). Logistic regression analysis demonstrated independent predictors for cardiac events to include age 65 years or older, acute blood loss anemia, and several comorbidities. CONCLUSION: Our results demonstrated an overall incidence of 6.7 cardiac complications per 1000 lumbar spine surgical procedures from 2002 to 2009. Patients undergoing lumbar fusion were more likely to experience cardiac events than lumbar decompression patients. Cardiac events tend to occur in patients with noted risk factors and result in increased hospitalizations, costs, and mortality. On the basis of these findings, we think that patients with specified risk factors should be monitored closely and medically optimized in the perioperative period.

Hospital outcomes and complications of anterior and posterior cervical fusion with bone morphogenetic protein.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: A nationwide population-based database was analyzed to identify the incidence of complications and mortality associated with bone morphogenetic protein (BMP) utilization in cervical spine fusion surgery. SUMMARY OF BACKGROUND DATA: "Off-label" use of BMP as an adjunct in cervical fusions has been associated with increased complication rates in small case series. The incidence of complications with utilization of BMP is not well characterized on a national level. METHODS: Data from the Nationwide Inpatient Sample were obtained for each year from 2002-2009. Patients undergoing anterior cervical fusion (ACF) or posterior cervical fusion for diagnoses of cervical myelopathy and/or radiculopathy were identified and separated into cohorts ("BMP" and "No BMP"). Patient demographics and comorbidities were compared. Complications, length of stay, costs, and mortality rates were assessed. Student t test and χ test were used to assess significant differences. A P value of less than 0.0005 was used to denote significance. RESULTS: A total of 213,421 ACFs and 20,334 posterior cervical fusions were identified from 2002-2009; 6.2% of all ACFs and 12.5% of posterior cervical fusions utilized BMP. Patients receiving BMP in the ACF group were older with greater comorbidities than patients who did not receive BMP (P < 0.0005). Both surgical groups with BMP experienced increased length of stay and costs. Overall complication rates were significantly greater when BMP was utilized in ACFs (P < 0.0005) due to a significantly higher rate of dysphagia (37.2 vs. 22.5 per 1000 cases) (P < 0.0005). CONCLUSION: Our study found that "off-label" use of BMP as an adjunct to cervical fusions was associated with increased rates of dysphagia in ACFs and increased costs for all cervical fusions. Our study does not measure long-term outcomes after discharge; however, the impact of increased inhospital costs, length of stay, and incidence of dysphagia with utilization of BMP should be considered prior to its use in cervical fusions.

The anti-catabolic role of bovine lactoferricin in cartilage.

Bovine lactoferricin (LfcinB) is a multifunctional peptide derived from bovine lactoferrin that demonstrates antibacterial, antifungal, antiviral, antitumor, and immunomodulatory activities. Recently, studies have focused on the anti-catabolic and anti-inflammatory potential of LfcinB. LfcinB is able to modulate the effects cytokines such as IL-1 and fibroblast growth factor 2 as well as promote specific cartilage anabolic factors. These properties are particularly important in maintaining cartilage homeostasis and preventing a catabolic state, which leads to clinical pathology. This review focuses on the recent literature elucidating the role of LfcinB in preventing cartilage degradation.

Radiation exposure has increased in trauma patients over time.

BACKGROUND: Computed tomography (CT) scans have become imaging modalities of choice in trauma centers. The purposes of this study were to evaluate the trend of radiation exposure in acute trauma patients. Our hypothesis was that radiation dosage and charges would increase over time without change in patient acuity or outcome. METHODS: Five hundred consecutive trauma patients were retrospectively reviewed for the years 2002, 2005, and 2008. Total number of CT scans, plain radiographs, and total radiation dosage (milliSieverts [mSV]) were determined. Charges were calculated. Injury severity scores and mortality were determined. RESULTS: The mean number of CT scans for category 1 patients in 2002, 2005, and 2008 was 1.5, 3.1, and 4.6, respectively (p = 0.01). This trend was similar in category 2 patients: 2.0, 3.5, 5.1, respectively (p < 0.01). Significant decreases in plain radiography were noted concurrently. This contributed to increased total radiation exposure to categories 1 and 2 patients over 2002, 2005, and 2008: 12.0 mSV, 23.6 mSV, and 33.6 mSV (p = 0.02); and 17.5 mSV, 24.1 mSV, and 37.5 mSV (p < 0.001), respectively. Charges for diagnostic imaging per patient also increased for categories 1 and 2 patients over 2002, 2005, and 2008: $2,933, $4,656, and $6,677; and $4,105, $5,344, and $7,365, respectively (all p < 0.01). Over the course of a year for 4,800 trauma patients treated at our hospital, this is expected to accrue additional charges of $13 million. CONCLUSION: The number of CT scans per trauma patient has more than doubled over 6 years, generating more radiation exposure and charges per patient, despite no change in mortality or injury severity. Judicious use of advanced imaging may control risks and costs without compromising care. LEVEL OF EVIDENCE: III, retrospective.