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Abstract: Background context: The safety of allograft material has come under scrutiny because of recent reports of allograft-associated bacterial and viral infections in tissue recipients. Gamma irradiation, although being one of the most effective ways of terminal sterilization, has been shown to affect the biomechanical properties of allograft bone. It may also have detrimental effects on the osteoinductivity of allograft material such as demineralized bone matrix (DBM) by the denaturation of proteins because of heat generated by irradiation. Sterilization of DBM material is an important variable in processing graft materials. This is considered to be one of the factors leading to different fusion rates observed with different commercially available DBM products, as the sterilization procedure itself may affect the osteoinductivity of the material. Currently, there is no ideal sterilization technique that limits the detrimental effect on osteoinductivity and fusion rates. Purpose: To evaluate the effects of a range of hydrogen peroxide exposures with or without the controlled high-dose gamma irradiation after processing with radioprotectant solutions (Clearant radiation sterilization procedure) on the fusion rates of human DBM. Study design: A prospective in vivo animal study. Methods: Eighty mature athymic nude female rats were used for this study, which formed 10 equal groups. Human DBM exposed to hydrogen peroxide for different time periods (0, 1, 6, and 24 hours) was divided into two major subgroups. One group was further treated with controlled high-dose radiation using radioprotectants (radiation treated), whereas the other group was frozen immediately without specific treatment (non-radiation treated). Both radiation-treated and non–radiation-treated DBM material from each group of hydrogen peroxide exposure times were implanted between L4 and L5 transverse processes of the rats forming eight test groups including eight animals in each. The remaining 16 rats were divided into two additional groups to form negative (only decortication, n=8) and positive (bone morphogenetic protein [BMP]-2, n=8) control groups. The rats were evaluated for fusion by radiographs (2, 4, and 8 weeks), manual palpation (8 weeks), and histological analysis after sacrificing. Comparison of fusion rate among all groups was made using these three evaluation methods. Results: Increasing the time period of hydrogen peroxide (0, 1, 6, or 24 hours) exposure for preparation of DBM from bone allograft did not affect the fusion rates significantly (p<.05), although there was a trend toward decreasing fusion rates with longer exposure times. When the hydrogen peroxide washed DBM preparations were also radiation treated, the resulting fusion rates were again not significantly different (p<.05). Agreement among fusion detection methods was found to be high. Conclusions: Hydrogen peroxide processing was not detrimental to fusion rates. The additional terminal sterilization technique with special gamma irradiation protocols (Clearant process) also did not decrease the fusion rates but could provide an additional margin of safety. [Copyright &y& Elsevier]

Abstract: Background context: Because pseudarthrosis remains a clinically significant complication after spinal arthrodesis, the role of recombinant bone morphogenetic proteins (BMPs) is continually evaluated in spine surgery. Purpose: This article reviews the important literature in clinical research involving the use of BMPs in the augmentation of spinal fusion. Study design/setting: Review article. Methods: A literature search was performed via MEDLINE through PubMed with the dates January 1960 to July 2007 using the keywords “bone morphogenetic protein, BMP, spinal arthrodesis, and/or bone healing.” Pertinent preclinical and clinical publications were chosen based on relevance and quality for inclusion in this study. Results: Publications focused on the historical context and potential clinical applications using BMP were selected to delineate the risks, benefits, and current indications for the augmentation of spinal arthrodesis. Conclusions: Although multiple commercially available recombinant BMPs have demonstrated clinical success in interbody and posterolateral fusions, the associated costs preclude its routine use in spinal arthrodesis. The spine surgeon must assess each patient individually based on age, bone quality, diagnosis, comorbidities, and risks of nonunion to determine the cost effectiveness of the use of BMP to augment spinal fusion. [Copyright &y& Elsevier]

Abstract: Background context: Painful lumbar disc degeneration is one of the most common ailments treated by spine surgeons. Currently, early disc disease and herniation are often treated with microdiscectomy. Late disc degeneration is usually treated with arthrodesis. With the advent of new technology and techniques in lumbar disc arthroplasty, interest in preserving spinal motion at degenerated motion segments has increased. The goals of lumbar disc arthroplasty are to provide long-term pain relief at the degenerated disc level, to restore disc height to protect neural elements and to preserve motion to prevent posterior facet arthropathy and adjacent segment disease. Purpose: The purpose of this review is to examine the anatomy and biomechanics of the lumbar motion segment to determine the features that successful disc arthroplasty prosthesis must possess. In addition, the early clinical results of three prostheses currently being used in humans are reviewed. Study design/setting: Review of the literature. Methods: A systematic review of Medline for articles related to lumbar disc arthroplasty was conducted up to and including journal articles published in August 2003. In addition, the abstracts from the annual meetings of the North American Spine Society and Scoliosis Research Society from 1998 to 2003 were searched. The literature was then reviewed and summarized. Results/conclusions: Short-term results of lumbar disc arthroplasty as measured by pain relief and disability are good in some studies. Implants are relatively safe in the short term, and with newer designs complications are usually related to the surgical approach rather than early implant failure. Recovery times appear to be shorter than arthrodesis. Despite the relatively good early clinical results of these devices, questions remain about the long-term efficacy in pain relief and maintenance of motion, the results of randomized comparative trials with fusion and the life span of the devices. In addition, late sequelae and revision options are unknown. Current indications for lumbar disc arthroplasty are in the setting of a Food and Drug Administration trial in young, nonosteoporotic patients with one or two level symptomatic disc degeneration without severe facet arthropathy, segmental instability or neural element compression requiring a posterior decompression. [Copyright &y& Elsevier]

Abstract: Background context: The use of minimally invasive lumbar intradiscal heating techniques, including intradiscal electro-thermal therapy (IDET), endoscopic radio-frequency annuloplasty, nucleoplasty and laser discectomy, for chronic lumbar discogenic pain and contained disc herniation has recently gained popularity. The purported therapeutic mechanisms of these interventions include subtotal nuclectomy, annular nociceptor ablation, and stabilization of the annular fibers. Basic science data elucidating the biomechanical and histomorphologic alterations of heat treatments on disc remain sparse. Purpose: The purpose of this study is to examine the effects of uniform heating on biomechanical properties and histomorphology of intervertebral disc tissues using a porcine model. Study design/setting: In a laboratory setting, porcine functional spinal units consisting of vertebra-nucleus pulposus-vertebra core and porcine hamstring tendons were harvested. Studies were performed on these tissue samples by uniformly heating the specimens in a constant temperature water bath. Ten porcine lumbar disc core and twenty-five porcine hamstring tendons were utilized as the subjects for this study. The effects of uniform heat treatments on disc core and hamstring tendon were measured for shrinkage, stiffness, and load to failure strength. Histomorphological study was also carried on the same specimen. Methods: The porcine vertebra-nucleus pulposus-vertebra segments were cored to a uniform 1-cm diameter. The hamstring tendons were cut to uniform 1.2-inch lengths. The tendon specimens were divided into groups of five each and heated in constant temperature water baths of 60°C, 65°C, 70°C, or 75°C for 10 min. Unheated specimens served as controls. The disc core specimens were divided in two group of five each, and tested at room temperature or after immersion in a 70°C bath. The shrinkage was monitored during immersion in the water bath. Biomechanical testing to failure was carried out using mechanical loading on an MTS servohydraulic testing machine operating under stroke control. Strength and stiffness of the tissue was determined. Histomorphology was studied by staining the specimen with hematoxylin and eosin (H&E), and examined under 200 times magnification. Non-heated controls were used for comparisons. Results: The porcine hamstring tendons had no measurable shrinkage in specimens heated up to 65°C. At temperatures above 65°C, the shrinkage was concluded within 2 min of immersion and 70°C appeared to be the optimal temperature, as temperatures higher than this did not demonstrate incremental effects. The disc core samples were heated to 70°C (optimum temperature), and there appeared to be gross contraction of the disc core circumference to visual inspection, but no measurable lengthwise shrinkage could be appreciated. Histologically, the specimens demonstrated progressive loss of individual collagen fiber outline as the temperature increased. In the tendons, at 75°C all of the fibers appear to be fused together, and the voids between individual collagen fibers were no longer present. Biomechanical testing revealed that the tendons undergo a substantial reduction in stiffness after heating. The mean tendon stiffness for the unheated specimens was 19,356 psi, while the corresponding value for the heated tendons was 1023 psi. These were significantly different using the paired t-test at p=0.0043. For the disc core samples, there was no significant difference in either stiffness (p=0.182) or failure strength (p=0.998) after heating. All failures occurred in mid-substance of the specimen. Conclusions: The application of uniform heating to nucleus pulposus disc core caused visible contraction of its circumference but not lengthwise shrinkage. The same heating shrinks the hamstring tendon and reduces its stiffness. Ultimate failure strength of the disc core specimen remains unchanged. The failure data was not obtainable for the tendon due to premature slippage from the fixation apparatus before failure. The results of this study fail to support a biomechanical justification for the application of uniform heat treatment to the whole intervertebral disc. Heating annulus fibrosus and nucleus pulposus separately to specific temperatures may have potential clinical benefits. [Copyright &y& Elsevier]

COMMENTARY ON: Olabisi RM, Lazard ZW, Heggeness MH, et al. An injectable method for noninvasive spine fusion. Spine J 2011;11:545–56 (in this issue). [ABSTRACT FROM AUTHOR]

Anterior cervical discectomy and fusion (ACDF) is a treatment for degenerative spine conditions when symptoms become refractory to conservative management. While pain and neurological function often improve after ACDF, some patients continue to have persistent pain and disability which can benefit from postoperative physical therapy (PT). With the potential advent of bundled payments in spine surgery, it is necessary to determine if the use of postoperative PT is cost-effective. To analyze the health care utilization associated with patients who underwent 1-2 level ACDF alone compared to those who underwent ACDF and postoperative PT. Retrospective database study. Patients who underwent 1,2-level ACDF for degenerative cervical pathologies from 2010-2021 (n=355,188) either with or without postoperative physical therapy. Health care utilization (advanced imaging, revisions, opioid use). PearlDiver database was used to identify patients who underwent 1,2-level ACDF for degenerative cervical spine disorders without or with postoperative PT from 2010-2021. Demographic and procedural data was obtained using International Classification of Disease 9th and 10th Revision (ICD-9, ICD-10) and Current Procedural Terminology (CPT) codes. Postoperative PT included active and passive PT CPT codes. Both Non-PT and PT groups were 1:1 propensity-matched for age, sex, and Elixhauser Comorbidity Index (ECI) scores. Health care utilization included revision surgery, opioid use, and advanced imaging. Advanced imaging was defined by computer tomography (CT) and/or magnetic resonance imaging (MRI) of the cervical spine. Chi-squared analysis, and independent t-test were performed to assess differences in health care utilization, between non-PT and PT subgroups at 2-, 6-, and 12 weeks postoperatively. A total of 355,188 patients underwent 1,2-level ACDF (n=215,764 no PT, n=139,424 with postoperative PT). PT cohort had significantly greater proportions of female patients (57.7% vs 53.5%, p<0.001), myelopathy (26.2% vs 23.3%; p<0.001) and preoperative opioid use (50.5% vs 48.8%; p<0.001). Non-PT cohort had higher proportions of obesity (9.7% vs 8.5%; p<0.001), smoking (21% vs 19.4%; p<0.001), and depression (13% vs 11.9%; p<0.001). Postoperative PT initiated at 2 weeks was associated with significantly more advanced imaging at 3,6 months (p=.012) and 30-day opioid use.(p=.047) and significantly less revisions (p=0.007) and opioid use at 18 months (p=.031); PT at 6 weeks was associated with significantly more advanced imaging at 3,6, 18 months (p<0.001, p=.008) and opioid use at 30 days, 3 months (p<0.001, p=.004) and significantly less opioid use at 9 months (p,.001); PT at 12 weeks was associated with significantly more advanced imaging at 30 days, 3-, 6-,18 months (p=.002, p<0.001) and opioid use at 30 days, 3 months (p<0.001, p=.032) although significantly less opioid use at 9 months (p=.011). No significant difference for other time points and groups. The benefits of postoperative PT for ACDF become more appreciable in the long-term for revisions and postoperative opioid use despite higher proportions of myelopathy and preoperative opioid use. Revision rates in the short-term were not significantly different between non- PT/PT cohorts. Advance imaging appears to be utilized significantly more when initiating postoperative PT at 6,12 weeks vs 2 weeks or no PT. Postoperative PT may aid in long term opioid usage after 1-2 level ACDF surgeries and may be initiated as early as 2 weeks without increased rate of revision surgery. Future prospective RCTs are needed to determine association of these findings with patient reported outcomes, return to work and quality of life. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: Adjacent segment disease (ASD) is a potential complication following lumbar spinal fusion.Purpose: This study aimed to demonstrate the demographic, clinical, and operative risk factors associated with ASD development following lumbar fusion.Study Design/setting: Systematic review and meta-analysis.Patient Sample: We identified 35 studies that reported risk factors for ASD, with a total number of 7,374 patients who had lumbar spine fusion.Outcome Measures: We investigated the demographic, clinical, and operative risk factors for ASD after lumbar fusion.Methods: A literature search was done using PubMed, Embase, Medline, Scopus, and the Cochrane library databases from inception to December 2019. The methodological index for non-randomized studies (MINORS) criteria was used to assess the methodological quality of the included studies. A meta-analysis was done to calculate the odds ratio (OR) with the 95% confidence interval (CI) for dichotomous data and mean difference (MD) with 95% CI for continuous data.Results: Thirty-five studies were included in the qualitative analysis, and 22 studies were included in the meta-analyses. The mean quality score based on the MINORS criteria was 12.4±1.9 (range, 8-16) points. Significant risk factors included higher preoperative body mass index (BMI) (mean difference [MD]=1.97 kg/m2; 95% confidence interval [CI]=1.49-2.45; p<.001), floating fusion (Odds ratio [OR]=1.78; 95% CI=1.32-2.41; p<.001), superior facet joint violation (OR=10.43; 95% CI=6.4-17.01; p<.001), and decompression outside fusion construct (OR=1.72; 95% CI=1.25-2.37; p<.001).Conclusions: The overall level of evidence was low to very low. Higher preoperative BMI, floating fusion, superior facet joint violation, and decompression outside fusion construct are significant risk factors of development of ASD following lumbar fusion surgeries. [ABSTRACT FROM AUTHOR]

Background Context: The concept of frailty has become increasingly recognized, and while patients with cancer are at increased risk for frailty, its influence on perioperative outcomes in metastatic spine tumors is uncertain. Furthermore, the impact of frailty can be confounded by comorbidities or metastatic disease burden.Purpose: The purpose of this study was to evaluate the influence of frailty and comorbidities on adverse outcomes in the surgical management of metastatic spine disease.Study Design/setting: Retrospective analysis of a nationwide database to include patients undergoing spinal fusion for metastatic spine disease.Patient Sample: A total of 1,974 frail patients who received spinal fusion with spinal metastasis, and 1,975 propensity score matched non-frail patients.Outcome Measures: Outcomes analyzed included mortality, complications, length of stay (LOS), nonroutine discharges and costs.Methods: A validated binary frailty index (Johns Hopkins Adjusted Clinical Groups) was used to identify frail and non-frail groups, and propensity score-matched analysis (including demographics, comorbidities, surgical and tumor characteristics) was performed. Sub-group analysis of levels involved was performed for cervical, thoracic, lumbar and junctional spine. Multivariable-regression techniques were used to develop predictive models for outcomes using frailty and the Elixhauser Comorbidity Index (ECI).Results: 7,772 patients underwent spinal fusion with spinal metastasis, of which 1,974 (25.4%) patients were identified as frail. Following propensity score matching for frail (n=1,974) and not-frail (n=1,975) groups, frailty demonstrated significantly greater medical complications (OR=1.58; 95% CI 1.33-1.86), surgical complications (OR=1.46; 95% CI 1.15-1.85), LOS (OR=2.65; 95% CI 2.09-3.37), nonroutine discharges (OR=1.79; 95% CI 1.46-2.20) and costs (OR=1.68; 95% CI 1.32-2.14). Differences in mortality were only observed in subgroup analysis and were greater in frail junctional and lumbar spine subgroups. Models using ECI alone (AUC=0.636-0.788) demonstrated greater predictive ability compared to those using frailty alone (AUC=0.633-0.752). However, frailty combined with ECI improved the prediction of increased LOS (AUC=0.811), cost (AUC=0.768), medical complications (AUC=0.723) and nonroutine discharges (AUC=0.718). Predictive modeling of frailty in subgroups demonstrated the greatest performance for mortality (AUC=0.750) in the lumbar spine, otherwise performed similarly for LOS, costs, complications, and discharge across subgroups.Conclusions: A high prevalence of frailty existed in the current patient cohort. Frailty contributed to worse short-term adverse outcomes and could be more influential in the lumbar and junctional spine due to higher risk of deconditioning in the postoperative period. Predictions for short term outcomes can be improved by adding frailty to comorbidity indices, suggesting a more comprehensive preoperative risk stratification should include frailty. [ABSTRACT FROM AUTHOR]

This abstract contains content that is significantly similar to the authors' previously published abstract in the Global Spine Journal Rapid Fire. For access to the original publication, please visit the following DOI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10226053/. [ABSTRACT FROM AUTHOR]

Abstract: Background Context: Lumbar discectomy is one of the most common spine surgical procedures. With the exception of true emergencies (eg, cauda equina syndrome), lumbar discectomy is usually performed as an elective procedure after a prudent trial of nonoperative treatment. Although several studies have compared costs of definitive operative or nonoperative management of lumbar disc herniation, no information has been published regarding the cost of conservative care in patients who ultimately underwent surgical discectomy. Purpose: The purpose of this study was to determine the financial costs (and relative distribution of those costs) associated with the nonoperative management of lumbar disc herniation in patients who ultimately failed conservative care and elected to undergo surgical discectomy. Study Design: This is a retrospective database review. Patient Sample: The sample comprises patients within the database who underwent lumbar discectomy. Outcome Measures: The outcome measures were frequency of associated procedures and the costs of those procedures. Materials and Methods: A search was conducted using a commercially available online database of insurance records of orthopedic patients to identify all patients within the database undergoing lumbar discectomy between 2004 and 2006. Patients were identified by American Medical Association Current Procedural Terminology code. The associated charge codes for the 90-day period before the surgery were reviewed and categorized as outpatient physician visits, imaging studies, physical therapy, injection, chiropractic manipulation, medication charges, preoperative studies, or miscellaneous charges. The frequency of each code and the percentage of patients for whom that code was submitted to the insurance companies were noted, as were the associated charges. Results: In total, 30,709 patients in the database met eligibility criteria. A total of $105,799,925 was charged during the 90 days preoperatively, an average of $3,445 per patient. Average charge for discectomy procedure was $7,841. Charges for injection procedures totaled $16,211,246 or 32% of total charges, diagnostic imaging $15,648,769 (31%), outpatient visits $6,552,135 (13%), physical therapy visits $5,723,644 (11%), chiropractic manipulation $1,177,406 (2%), preoperative studies $426,976 (0.8%), medications $263,039 (0.5%), and miscellaneous charges $1,177,371 (2%). Conclusions: Charges for preoperative care of patients with lumbar disc herniation are substantial and are split almost evenly between diagnostic charges (outpatient visits, imaging, laboratory studies, and miscellaneous) and therapeutic charges (injections, physical therapy, chiropractic manipulation, and medications). Although a large number of patients will ultimately require surgical intervention, given that many patients will improve with nonoperative therapy, a trial of conservative management is appropriate. Additional studies to identify patients who may ultimately fail nonoperative treatment and would benefit from early discectomy would be beneficial. [Copyright &y& Elsevier]

Background Context: High quality evidence is difficult to generate, leaving substantial knowledge gaps in the treatment of spinal conditions. Appropriate use criteria (AUC) are a means of determining appropriate recommendations when high quality evidence is lacking.Purpose: Define appropriate use criteria (AUC) of cervical fusion for treatment of degenerative conditions of the cervical spine.Study Design/setting: Appropriate use criteria for cervical fusion were developed using the RAND/UCLA appropriateness methodology. Following development of clinical guidelines and scenario writing, a one-day workshop was held with a multidisciplinary group of 14 raters, all considered thought leaders in their respective fields, to determine final ratings for cervical fusion appropriateness for various clinical situations.Outcome Measures: Final rating for cervical fusion recommendation as either "Appropriate," "Uncertain" or "Rarely Appropriate" based on the median final rating among the raters.Methods: Inclusion criteria for scenarios included patients aged 18 to 80 with degenerative conditions of the cervical spine. Key modifiers were defined and combined to develop a matrix of clinical scenarios. The median score among the raters was used to determine the final rating for each scenario. The final rating was compared between modifier levels. Spearman's rank correlation between each modifier and the final rating was determined. A multivariable ordinal regression model was fit to determine the adjusted odds of an "Appropriate" final rating while adjusting for radiographic diagnosis, number of levels and symptom type. Three decision trees were developed using decision tree classification models and variable importance for each tree was computed.Results: Of the 263 scenarios, 47 (17.9 %) were rated as rarely appropriate, 66 (25%) as uncertain and 150 (57%) were rated as appropriate. Symptom type was the modifier most strongly correlated with the final rating (adjusted ρ2 = 0.58, p<.01). A multivariable ordinal regression adjusting for symptom type, diagnosis, and number of levels and showed high discriminative ability (C statistic = 0.90) and the adjusted odds ratio (aOR) of receiving a final rating of "Appropriate" was highest for myelopathy (aOR, 7.1) and radiculopathy (aOR, 4.8). Three decision tree models showed that symptom type and radiographic diagnosis had the highest variable importance.Conclusions: Appropriate use criteria for cervical fusion in the setting of cervical degenerative disorders were developed. Symptom type was most strongly correlated with final rating. Myelopathy or radiculopathy were most strongly associated with an "Appropriate" rating, while axial pain without stenosis was most associated with "Rarely Appropriate." [ABSTRACT FROM AUTHOR]

Background Context: Posterior cervical foraminotomy (PCF) is a relatively safe procedure for the treatment of cervical radiculopathy. Though most often performed as an inpatient procedure, there is an increasing number of patients treated in an outpatient setting.Purpose: This study aimed to compare the perioperative complication rates associated with inpatient and outpatient single-level PCF.Study Design/setting: Retrospective database study.Patient Sample: Patients with cervical radiculopathy who underwent inpatient or outpatient single-level PCF between 2007 to the first quarter of 2016.Outcome Measures: Charlson Comorbidity Index (CCI) was used as a broad measure of comorbidity. Surgical complications included cervical nerve root injury, dural tear, wound complications, infection, dysphagia, cervicalgia, and revision surgery. Medical complications included pulmonary embolism and lower limb deep vein thrombosis, acute myocardial infarction, acute respiratory failure, pneumonia, sepsis, and urinary complications.Methods: This study was a retrospective review of patients who received single-level PCF from 2007 to the first quarter of 2016 as either outpatients or inpatients using the Humana subset of the PearlDiver Patient Record Database. The incidence of perioperative medical and surgical complications was queried using relevant International Classification of Diseases (ICD-9-CM and ICD-10-CM) and Current Procedural Terminology codes. Multivariate logistic regression analysis, adjusted for age, gender, and CCI, was performed to calculate odds ratios (ORs) of complications among inpatients relative to outpatients treated with PCF. Propensity score matching was done, and comparisons were made for postoperative complications.Results: Throughout the time period, 1,469 and 1,192 patients received inpatient and outpatient single-level PCF, respectively. The mean CCIs±standard deviation of inpatient and outpatient groups undergoing PCF were 2.83±3.11 and 1.46±2.21, respectively (p<.001). After propensity score matching, patients who received PCF in an inpatient setting showed significantly higher rates of wound complications (OR=1.53, 95% confidence interval [CI]=1.04-2.23; p=.029), infection (OR=1.91, CI=1.15-3.15; p=.012), acute respiratory failure (OR=2.50, CI=1.23-5.08; p=.011), and urinary tract infections and incontinence (OR=2.11, CI=1.32-3.38; p=.002).Conclusions: Outpatient single-level PCF was associated with a lower rate of perioperative medical and surgical complications. The PCF in the outpatient setting can potentially be a safe procedure for the treatment of cervical radiculopathy with appropriate patient selection. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Anterior Cervical Discectomy and Fusion (ACDF) and Posterior Cervical Fusion (PCF) are surgical techniques for the treatment of degenerative disc disease with established efficacy and safety. However, patients with Obstructive Sleep Apnea (OSA) present with additional risk due to preexisting airway obstruction. Pulmonary complications of patients with OSA who undergo cervical fusion have not been well studied. PURPOSE This study aims to review rates of pulmonary complications following one- or two-level cervical fusion within patients with preexisting OSA. STUDY DESIGN/SETTING Retrospective database study. PATIENT SAMPLE Patients who were diagnosed with OSA within 1 year prior to undergoing one- or two-level ACDFor one- or two-level PCF. OUTCOME MEASURES Postoperative pulmonary complications that developed within three months following surgery, including: bronchitis, bronchiectasis, chronic airway obstruction, lung diseases, dyspnea, respiratory complications, and pneumonia. METHODS The PearlDiver insurance database was queried for Humana patients who were diagnosed with OSA within 1 year prior to undergoing one- or two-level ACDF (CPT-22548, CPT-22551, CPT-22552, CPT-22554, CPT-22585) or one- or two-level PCF (CPT-22590, CPT-22595, CPT-22600, CPT-22614) between 2005 and 2015. The search resulted in 3,748 patients who had OSA prior to ACDF, 24,838 patients who did not have OSA prior to ACDF, 543 patients who had OSA prior to PCF, and 4,034 patients who did not have OSA prior to PCF. Postoperative pulmonary complications that developed within three months following surgery, including: bronchitis, bronchiectasis, chronic airway obstruction, lung diseases, dyspnea, respiratory complications, and pneumonia were then compared between the four groups. RESULTS Patients who were diagnosed with OSA within 1 year prior to undergoing cervical fusion were at a significantly greater risk for developing postoperative pulmonary complications. Patients with OSA who underwent ACDF showed greater rates of chronic airway obstruction 17.4% versus 8.9% (odds ratio [OR]=2.163, p<.001), bronchitis 7.6% versus 3.9% (OR=2.059, p<.001), dyspnea 16.1% versus 9.7% (OR=2.004, p<.001), lung diseases 8.1% versus 5.5% (OR=1.534, p<.001), and pneumonia 3.9% versus 2.7% (OR=1.476, p<.001). Patients with OSA who underwent PCF also showed greater risk of developing chronic airway obstruction 22.8% versus 14.1% (OR=1.799, p<.001) and bronchitis 9.2% versus 6.2% (OR=1.532, p=.008). CONCLUSIONS Prior diagnosis of OSA within 1 year prior to patients undergoing one- or two-level cervical fusion is associated with greater rates of postoperative pulmonary complications within three months following surgery. Patients with OSA who underwent ACDF were at a greater risk of developing pulmonary complications than patients with OSA who underwent PCF. [ABSTRACT FROM AUTHOR]

Background Context: Previous studies have found an association between mental illness and poor outcomes in spine surgery, but little is known about the effects of depression and/or anxiety on the adult spinal deformity population. In addition, most relevant studies exclusively focused on the lumbar spine and had relatively small patient sizes.Purpose: The aim of this study was to investigate whether adult spinal deformity patients with depression and/or anxiety have an increased risk of postoperative complications and reoperation following posterior thoracolumbar spinal surgery.Study Design/setting: Retrospective database study.Methods: Adult patients (over 18 years of age) with a diagnosis of spinal deformity undergoing any reconstructive thoracic or thoracolumbar spinal procedure with a posterior approach between 2007 and 2015 Q2 were identified using Current Procedural Terminology codes to query the Pearl Diver patient record database (Pearl Diver Technologies, West Conshohocken, PA, USA). The database includes records of approximately 18 million patients across the United States having Humana insurance. Further selection of patients with depression and/or anxiety and their associated postoperative complications were identified using ICD-9 and ICD-10 diagnosis codes (International Classification of Diseases 9th-10th edition). The mental illness cohort was matched to a control group according to age, sex, and Charlson Comorbidity Index. Patient data was analyzed for reoperation rates and incidence of common postoperative complications.Results: Multilevel posterolateral fusion was the most common included posterior thoracic reconstructive surgery. The mental illness cohort (n = 327) had significantly increased rates of infection (odds ratio [OR] = 1.743, p = .022) and respiratory complications (OR = 1.492, p = .02) at the 90-day postoperative period. The rates of incision and drainage (OR = 1.379, p = .475) and pneumonia (OR = 1.22, p = .573) were increased in the mental illness cohort at the 90-day postoperative period, but not significantly. There were no significant differences in complication and reoperation rates at 1-year postoperatively.Conclusions: Patients with spinal deformity and pre-existing depression and/or anxiety treated with a posterior thoracolumbar reconstructive spinal surgery had significantly elevated risk of postoperative infections and respiratory complications when compared with the control group. [ABSTRACT FROM AUTHOR]

Background Context: Cervical sagittal vertical axis (cSVA) of ≥40 mm is recognized as the key factor of poor health-related quality of life, poor surgical outcomes, and correction loss after surgery for cervical deformity. However, little is known about the radiological characteristics of patients with cSVA≥40 mm.Purpose: The purpose of this study was to identify the radiological characteristics of patients with cervical imbalance.Design: Retrospective analysis of weight-bearing cervical magnetic resonance (MR) images.Patient Sample: Consecutive 1,500 MR images of symptomatic patients in weight-bearing position.Outcome Measures: Cervical sagittal vertical axis, cervical alignment, cervical balance parameters (T1 slope, Co-C2 angle, C2-C7 angle, C7-T1 angle, neck tilt, and thoracic inlet angle), disc degeneration (Pfirmann and Suzuki classification), end plate degeneration (Modic change), spondylolisthesis (antero- and retrolisthesis), anteroposterior (AP) diameter of dural sac, cross-sectional area (CSA), and fat infiltration ratio of the transversospinalis muscles at C4 and C7 levels.Methods: Patients were divided into two groups: cSVA≥40 mm and cSVA<40 mm. Gender, age, and cervical alignment were analyzed. Subsequently, matched imbalance (cSVA≥40 mm) and control (<40 mm) groups were created using the propensity score to adjust for age, gender, and cervical alignment. Cervicothoracic angular parameters, disc degeneration, Modic change, spondylolisthesis, and degeneration of the transversospinalis muscles at C4 and C7 were compared. Variables with p<.05 were included in the multinomial logistic regression model to identify factors that relate to the cervical balance grouping.Results: The incidence of patients with cervical imbalance was 2.5% (37 patients). Those patients had a higher incidence of kyphosis, were older, and there were more male patients. In the matched imbalance group, the T1 slope was greater (p=.028), C7-T1 lordotic angle was smaller (p<.001), the number of anterolisthesis was greater (p=.012), and the fat infiltration ratio at C4 and C7 was higher (p=.023, 0.030) compared with the control. Logistic regression analysis showed that the C7-T1 angle (adjusted odds ratio [aOR]=0.592, p=.001) and fat infiltration ratio at C7 level (aOR=1.178, p=.030) were significant independent variables.Conclusions: Smaller C7-T1 lordotic angle and severe muscle degeneration at C7 level were independent characteristics of patients with cervical imbalance. [ABSTRACT FROM AUTHOR]

Lumbar spinal fusion is widely used in treating degenerative and traumatic conditions of the lumbar spine. The impact of chronic hyperlipidemia on perioperative complications has not been yet investigated. This study compared the perioperative complications of single- and multi-level lumbar fusions in patients with and without chronic hyperlipidemia. Retrospective database study. Patients with or without chronic hyperlipidemia who underwent single- or multilevel lumbar fusions between 2010 and 2019. Perioperative surgical and medical complications. A nationwide claims database, PearlDiver, was utilized for this study. International Classification of Diseases (ICD-9 and ICD-10) codes were used to identify patients with chronic hyperlipidemia. Current Procedural Terminology (CPT) codes were used to identify lumbar spinal fusion surgeries. Utilizing the appropriate ICD-9, ICD-10 and CPT codes, we retrieved the perioperative surgical and medical complications. Propensity score matching was implemented to control for the confounding factors, including age, gender and Elixhauser Comorbidity Index (ECI). Chi-square test was used to compare the incidence of complications among groups. Single-level lumbar fusions included a total of 65,674 patients: with hyperlipidemia (n=18,395) and without hyperlipidemia (n=47,279). Propensity score matching resulted in 16,930 patients in each group. Patients with hyperlipidemia had a higher incidence of wound complications (481 [2.8%] vs 357 [2.1%], P < 0.001), surgical site infection (370 [2.2%] vs 231 [1.4%], P < 0.001), failed back syndrome (1914 [11.3%] vs 1605 [9.5%], P < 0.001), hardware removal (1,006 [5.9%] vs 761 [4.5%], P < 0.001), deep venous thrombosis/pulmonary embolism (264 [1.6%] vs 216 [1.3%], P=0.031), myocardial infarction (81 [0.5%] vs 23 [0.1%], P < 0.001), cerebrovascular accident (86 [0.5%] vs 39 [0.2%], P < 0.001), renal failure (305 [1.8%] vs 197 [1.2%], P < 0.001), sepsis (103 [0.6%] vs 51 [0.3%], P < 0.001), urinary tract infection/incontinence (697 [4.1%] vs 436 [2.6%], P < 0.001). Multilevel lumbar fusions included a total of 48,928 patients: with hyperlipidemia (n=15,527) and without hyperlipidemia (n=33,401). Propensity score matching resulted in 14,218 patients in each group. Patients with hyperlipidemia had a higher incidence of nerve root injury (33 [0.2%] vs 17 [0.1%], P=0.034), wound complications (624 [4.4%] vs 508 [3.6%], p < 0.001), surgical site infection (438 [3.1%] vs 307 [2.2%], p < 0.001), failed back syndrome (2,024 [14.2%] vs 1,642 [11.5%], p < 0.001), hardware removal (1,146 [8.1%] vs 885 [6.2%], p < 0.001), revision (922 [6.5%] vs 1,055 [7.4%], P=0.002), myocardial infarction (120 [0.8%] vs 41 [0.3%], p < 0.001), renal failure (472 [3.3%] vs 313 [2.2%], p < 0.001), urinary tract infection (810 [5.7%] vs 618 [4.3%], p < 0.001). Following single- or multilevel lumbar fusions, patients with chronic hyperlipidemia have an increased risk of perioperative complications, including wound complications, surgical site infection, failed back syndrome, hardware removal, myocardial infarction, renal failure and urinary tract infection. In multilevel lumbar fusions, chronic hyperlipidemia is associated with a higher incidence of nerve root injury and revision rates. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Several studies have shown that factors such as insurance type and patient income are associated with different readmission rates following certain orthopaedic procedures. The present study evaluates 30-day complication and readmission rates as a function of hospital type, insurance type, and patient median income in patients undergoing lumbar spine fusion. Retrospective cohort analysis Using the National Readmissions Database (NRD), we identified patients who underwent a primary lumbar spine fusion from 2010-2016. Primary outcome measures were 30-day readmission and complication rates. Complications of interest were infection, wound injury, hematoma, neurological injury, thromboembolic event, and hardware failure. International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) codes were used to identify 596,568 patients who underwent a primary lumbar spine fusion from 2010-2016. Three separate analyses were performed using hospital type, insurance type, and patient income quartile as independent variables. Hospital type included the following groups: metropolitan non-teaching (n=212,131), metropolitan teaching (n=364,752), and rural (n=19,685). Insurance type was divided into 4 groups: Medicare (n=213,534), Medicaid (n=78,520), private insurance (n=196,648), and out-of-pocket payers (n=45,025). Income quartiles included Quartiles 1 (n=112,083), 2 (n=145,755), 3 (n=156,276), and 4 (n=147,289), with Quartile 1 corresponding to the poorest populations and Quartile 4 to the wealthiest populations. Nonparametric Kruskal-Wallis testing, followed by Dunn's pairwise comparisons were used to analyze differences in 30-day complication and readmission rates between cohorts. Statistical tests were two-sided with significance level set at α = 0.05. Thirty-day readmission was significantly higher in metropolitan teaching hospitals compared to metropolitan non-teaching and rural hospitals (p < 0.05). Metropolitan teaching hospitals had significantly higher rates of infection (p < 0.001), wound injury (p < 0.001), hematoma (p=0.018) and hardware failure (p < 0.002) compared to metropolitan nonteaching hospitals. Privately insured patients were significantly less likely to be readmitted at 30 days than Medicare or Medicaid beneficiaries (p < 0.01). Privately insured patients also experienced significantly lower rates of hematoma formation than Medicare patients and out-of-pocket payers (p < 0.01), wound injury compared to Medicaid patients and out-of-pocket payers (p < 0.005), and infection compared to all other groups (p < 0.001). Patients in Quartile 4 had significantly greater rates of hematoma formation than those in Quartiles 1 and 2 (p < 0.02) and were more likely to experience a thromboembolic event compared to all other groups (p < 0.002). Patients undergoing lumbar spine fusion at metropolitan nonteaching hospitals and paying with private insurance had significantly lower 30-day readmission rates than their counterparts. Complications within 30 days following lumbar spine fusion were significantly higher in patients treated at metropolitan teaching hospitals and in Medicare and Medicaid beneficiaries. Aside from a few exceptions, patient income was generally not associated with differential complication rates. Further understanding of how various hospital characteristics and sociodemographic factors may impact patient outcomes is essential in mitigating drivers of inequitable outcomes in patients undergoing lumbar spine fusion. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Cervical intervertebral disc (IVD) degeneration is a common cause of neck and arm pain in adults and a frequent finding in imaging studies. This study aimed to assess the age-related degenerations of the cervical IVDs at each cervical spinal level in different age groups using the kinematic magnetic resonance imaging (KMRI). Cross-sectional study using KMRI. This study included 1300 symptomatic patients who had undergone upright cervical spine KMRI from February 2019 to November 2021. Pfirrmann classification of intervertebral disc degeneration. Patients were divided into five equal groups, each with 260 patients based on their ages. Group 1 included patients from 20 to 29 years, group 2 from 30 to 39 years, group 3 from 40 to 49 years, group 4 from 50 to 59 years, and group 5 were patients aged 60 years and above. On T2-weighted sagittal MRI, Pfirrmann grading system was used to grade the IVD degeneration into five grades. Considerable disc degeneration was reported with a Pfirrmann grade IV or V. A total of 7800 cervical IVDs from C2/3 to C7/T1 were evaluated. The severity and pattern of IVD degeneration in each age group was analyzed. Overall, 4.4% of discs were grade I, 21.0% grade II, 55.1% grade III, 17.1% grade IV, and 2.5% grade V. The number of degenerated discs increased gradually with age groups; 4.9%, 8.4%, 16.4%, 24.6%, and 43.4% in groups 1, 2, 3, 4, and 5, respectively, P < 0.001. In group 1, the most common grade was grade II (41.5%), and the most common degenerated level was C2/3 (25%). In group 2, the most common grade was grade III (53.1%), and the most common degenerated level was C5/6 (29.0%). In group 3, the most common grade was grade III (60.2%), and the most common degenerated level was C5/6 (33.1%). In group 4, the most common grade was grade III (67.0%), and the most common degenerated level was C5/6 (31.3%). In group 5, the most common grade was grade III (56.0%), and the most common degenerated level was C5/6 (24.8%). In all groups, C7/T1 was the least common degenerated disc (6.6%, 3.1%, 3.5%, 4.7% and 8.7% in groups 1, 4 and 5, respectively). In groups 1 and 2, 92.1% and 86.3% of subjects, did not have considerable disc degeneration. In group 5, 19.5% of patients had 2-level disc degeneration, 15.5% had 3-level disc degeneration, and the incidence of 6-level degeneration was 11.2%. In patients with single-level disc degeneration, C5/6 was the most common degenerated level (45.3%). In patients with 2-level degeneration, C5/6 and C6/7 were the most common (49.7%). In patients with 3-level degeneration, C4/5, C5/6, and C6/7 were the most common (38.5%). In patients with 4-level degeneration, C2/3, C3/4, and C5/6 were the most common (36.2%). Skip-level degeneration was found in 18.2%, 30.2%, and 20.3% of patients with 2-level, 3-level, and 4-level degeneration, respectively. This study evaluated the severity and pattern of IVD degeneration at each level of the cervical spine in different age groups. The number and severity of degenerated discs increases with age. Adjacent-level degeneration is more common than skip-lesion degeneration in patients with multilevel disc degeneration. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

In recent decades, overuse and misuse of opioids has led to a national epidemic of opioid-related harm in the United States, and chronic neck and back pain are a leading source of opioid prescriptions. Recent data suggest that chronic preoperative opioid use is a risk factor for complications following spine surgery as well as for postoperative opioid dependence, both of which increase health care expenditures. However, none of these studies focus on an older adult population. Older adults have shown increasing rates of opioid use disorders in recent decades and typically suffer more comorbidities and complications, and incur higher health care costs than the general population. This study investigated the degree to which chronic preoperative opioid use is a risk factor for postoperative complications, opioid dependence and insurance reimbursement in an older population undergoing anterior cervical discectomy and fusion (ACDF). Retrospective database study. Patients who underwent ACDF procedure. Postoperative complications, postoperative opioid dependence, and insurance reimbursement. Adults over 65 years-old who underwent ACDF between 2010 and 2020 were identified using a national insurance database. Patients with infection, spinal trauma or malignancy were excluded. Chronic preoperative opioid use was defined as active opioid prescription in three or more consecutive months before surgery. Postoperative opioid dependence was defined similarly for three months postoperatively. Insurance reimbursement was measured postoperatively at 3-month and 6-month intervals. Bivariate logistic regression was used to analyze the association between chronic preoperative opioid use and postoperative complications, chronic preoperative opioid use and postoperative opioid dependence, and chronic preoperative opioid use and insurance reimbursement. A total of 40,591 patients were included, of which 4,135 (10.2%) were prescribed chronic preoperative opioids and 25,300 (62.3%) were not prescribed any opioids preoperatively. Chronic preoperative opioid use was a risk factor for chronic opioid use postoperatively (OR=11.7, p<0.0001), readmission (OR=1.36, p<0.01), gastrointestinal complications (OR=1.36, p<0.001), and respiratory complications (OR=1.21, p<0.01). Mean reimbursements were higher for the chronic opioid group than the no opioids group at both the 3- and 6-month time points. This study demonstrates that chronic opioid use preceding ACDF is a risk factor for multiple postoperative medical complications as well as postoperative opioid dependence in elderly patients. The data suggest that patients with chronic opioid use preoperatively are unlikely to stop using opioids after surgery. Future studies should consider additional risk factors for postoperative opioid dependence, particularly those which are common in the older population, and alternatives to opioids for pain management prior to surgery. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: The thoracic spine was previously known as a relatively stable region in human spine. Several studies reported that the motion of the thoracic spine and changes in the cross-sectional area of the spinal cord changed with positions in the sagittal plane. The kinematic relationship between the thoracic disc and the space available for cord (SAC) with the positional change is still not well investigated.Purpose: The objective of this study was to evaluate the kinematic change of the intervertebral disc and space available for the spinal cord of the thoracic spine using kinematic magnetic resonance imaging (kMRI).Study Design: This is a retrospective study.Patient Sample: The patient sample included 105 patients who underwent thoracic spine kMRI.Outcome Measurement: Disc bulging and the SAC were evaluated from T4-T5 to T11-T12 in flexion, neutral, and extension positions.Methods: MRAnalyzer3 (TrueMRI Corporation, Bellflower, CA, USA) was used to analyze disc bulging and SAC from T4-T5 to T11-T12. The Friedman test was used to analyze the differences in disc bulging and SAC between neutral, flexion, and extension positions at each segment. The Wilcoxon signed-rank test was used for post hoc analysis for the significant levels from the Friedman test.Results: The mean value of the thoracic intervertebral disc area from T4-T5 to T11-T12 tended to be larger in flexion than in extension. Initial analysis with the Friedman test revealed a significant difference in disc bulging at T8-T9, T9-T10, and T11-T12 among the three positions (p<.05). Post hoc analysis showed that disc bulging was only significant at T8-T9 between flexion and extension (p<.001), at T9-T10 between neutral and flexion (0.003), and at T9-T10 between flexion and extension (p=.004). The SAC from T4-T5 to T11-T12 tended to be widest in extension and narrowest in flexion. Only T5-T6 exhibited a statistically significant difference in SAC between flexion and extension (p=.002).Conclusions: The thoracic discs and the SAC from T4-T5 to T11-T12 showed kinematic changes from flexion to extension. The thoracic spinal canal tended to be narrowest in flexion and widest in the extension. Thus, kyphotic deformities could be one of the etiologies for neurogenic deterioration in patients with thoracic myelopathy. [ABSTRACT FROM AUTHOR]

Background Context: With the changing landscape of health care, outpatient spine surgery is being more commonly performed to reduce cost and to improve efficiency. Anterior cervical discectomy and fusion (ACDF) is one of the most common spine surgeries performed and demand is expected to increase with an aging population.Purpose: The objective of this study was to determine the nationwide trends and relative complication rates associated with outpatient ACDF.Study Design/setting: This is a large-scale retrospective case control study.Patient Sample: The patient sample included Humana-insured patients who underwent one- to two-level ACDF as either outpatients or inpatients from 2011 to 2016 OUTCOME MEASURES: The outcome measures included incidence and the adjusted odds ratio (OR) of postoperative medical and surgical complications within 1 year of the index surgery.Materials and Methods: A retrospective review was performed of the PearlDiver Humana insurance records database to identify patients undergoing one- to two-level ACDF (Current Procedural Terminology [CPT]-22551 and International Classification of Diseases [ICD]-9-816.2) as either outpatients or inpatients from 2011 to 2016. The incidence of perioperative medical and surgical complications was determined by querying for relevant ICD and CPT codes. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate ORs of complications among outpatients relative to inpatients undergoing ACDF.Results: Cohorts of 1,215 patients who underwent outpatient ACDF and 10,964 patients who underwent inpatient ACDF were identified. The median age was in the 65-69 age group for both cohorts. The annual relative incidence of outpatient ACDF increased from 0.11 in 2011 to 0.22 in 2016 (R2=0.82, p=.04). Adjusting for age, gender, and comorbidities, patients undergoing outpatient ACDF were more likely to undergo revision surgery for posterior fusion at both 6 months (OR 1.58, confidence interval [CI] 1.27-1.96, p<.001) and 1 year (OR 1.79, CI 1.51-2.13, p<.001) postoperatively. Outpatient ACDF was also associated with a higher likelihood of revision anterior fusion at 1 year postoperatively (OR 1.46, CI 1.26-1.70, p<.001). Among medical complications, postoperative acute renal failure was more frequently associated with outpatient ACDF than inpatient ACDF (OR 1.25, CI 1.06-1.49, p=.010). Adjusted rates of all other queried surgical and medical complications were comparable.Conclusions: Outpatient ACDF is increasing in frequency nationwide over the past several years. Nationwide data demonstrate a greater risk of perioperative surgical complications, including revision anterior and posterior fusion, as well as a higher risk of postoperative acute renal failure. Candidates for outpatient ACDF should be counseled and carefully selected to reduce these risks. [ABSTRACT FROM AUTHOR]

Background Context: T1 slope is a novel thoracic parameter used to assess cervical spine sagittal balance. Thoracic index (TI) parameters including T1 slope and cervical sagittal alignment parameters may play an important role in degenerative cervical spondylolisthesis (DCS). Current literature regarding the relationship between TI and cervical sagittal alignment parameters in patients with DCS is limited.Purpose: (1) To evaluate the T1 slope, cervical sagittal alignment, and thoracic inlet parameter in patients with DCS using kinematic magnetic resonance imaging (kMRI), and (2) to find a correlation between the T1 slope, TI, and other cervical sagittal parameters in patients with DCS.Design/setting: Retrospective kMRI study, Level III.Patient Sample: Fifty-two patients with DCS from 1,128 patients from a cervical kMRI database.Outcome Measures: T1 slope, C2-C7 angle, sagittal vertical axis C2-C7 (SVA C2-C7), cranial tilt, cervical tilt, neck tilt, and thoracic inlet angle (TIA).Methods: Cervical spine kMRIs of 52 patients with DCS (mean age 51.7±standard deviation) were analyzed in neutral, flexion, and extension positions. Patients with DCS were divided into two groups: anterolisthesis (N=33) and retrolisthesis (N=19). Each listhesis group was subclassified into grade 1 (slip 2-3 mm) and grade 2 (slip>3 mm).Results: Grade 2 retrolisthesis had the largest T1 slope followed by grade 1 retrolisthesis, grade 2 anterolisthesis, and grade 1 anterolisthesis. Significant differences were found between the anterolisthesis and the retrolisthesis groups in the neutral position (p=.025). The flexion position had the largest T1 slope and showed a significant difference with anterolisthesis in the neutral position (p=.041). Sagittal vertical axis C2-C7 showed strong correlation with cranial tilt in all DCS groups and all positions.Conclusions: In our study, T1 slope was larger in grade 2 DCS, and the retrolisthesis group had larger T1 slope than the anterolisthesis group. Presence of larger T1 slope was significantly correlated with larger cervical lordosis curvature. Furthermore, cranial tilt was strongly correlated with SVA C2-C7. [ABSTRACT FROM AUTHOR]

Background Context: Watertight dural repair is crucial for both incidental durotomy and closure after intradural surgery.Purpose: The study aimed to describe a perfusion-based cadaveric simulation model with cerebrospinal fluid (CSF) reconstitution and to compare spine dural repair techniques.Study Design/setting: The study is set in a fresh tissue dissection laboratory.Sample Size: The sample includes eight fresh human cadavers.Outcome Measures: A watertight closure was achieved when pressurized saline up to 40 mm Hg did not cause further CSF leakage beyond the suture lines.Methods: Fresh human cadaveric specimens underwent cannulation of the intradural cervical spine for intrathecal reconstitution of the CSF system. The cervicothoracic dura was then exposed from C7-T12 via laminectomy. The entire dura was then opened in six cadavers (ALLSPINE) and closed with 6-0 Prolene (n=3) or 4-0 Nurolon (n=3), and pressurized with saline via a perfusion system to 60 mm Hg to check for leakage. In two cadavers (INCISION), six separate 2-cm incisions were made and closed with either 6-0 Prolene or 4-0 Nurolon, and then pressurized. A hydrogel sealant was then added and the closure was pressurized again to check for further leakage.Results: Spinal laminectomy with repair of intentional durotomy was successfully performed in eight cadavers. The operative microscope was used in all cases, and the model provided a realistic experience of spinal durotomy repair. For ALLSPINE cadavers (mean: 240 mm dura/cadaver repaired), the mean pressure threshold for CSF leakage was observed at 66.7 (±2.9) mm Hg in the 6-0 Prolene group and at 43.3 (±14.4) mm Hg in the 4-0 Nurolon group (p>.05). For INCISION cadavers, the mean pressure threshold for CSF leakage without hydrogel sealant was significantly higher in 6-0 Prolene group than in the 4-0 Nurolon group (6-0 Prolene: 80.0±4.5 mm Hg vs. 4-0 Nurolon: 32.5±2.7 mm Hg; p<.01). The mean pressure threshold for CSF leakage with the hydrogel sealants was not significantly different (6-0 Prolene: 100.0±0.0 mm Hg vs. 4-0 Nurolon: 70.0±33.1 mm Hg). The use of a hydrogel sealant significantly increased the pressure thresholds for possible CSF leakage in both the 6-0 Prolene group (p=.01) and the 4-0 Nurolon group (p<.01) when compared with mean pressures without the hydrogel sealant.Conclusions: We described the feasibility of using a novel cadaveric model for both the study and training of watertight dural closure techniques. 6-0 Prolene was observed to be superior to 4-0 Nurolon for watertight dural closure without a hydrogel sealant. The use of a hydrogel sealant significantly improved watertight dural closures for both 6-0 Prolene and 4-0 Nurolon groups in the cadaveric model. [ABSTRACT FROM AUTHOR]

Background Context: Minimally invasive sacroiliac (SI) joint fusion has become increasingly relevant in recent years as a treatment for SI joint pathology. Previous studies have found minimally invasive SI fusion to be an effective and safe treatment option for chronic SI joint pain. However, these studies have been primarily single-center, case-based, or manufacturer-sponsored investigations, and as such their findings are limited to their sample populations.Purpose: The aim of this study was to investigate the safety of minimally invasive SI fusion using a large nationwide sample group to more accurately identify complication rates of this increasingly popular procedure.Study Design/setting: This is a retrospective database study.Patient Sample: The sample includes patients within the orthopedic subset of Humana database who underwent minimally invasive SI fusion between 2007 and 2014.Outcome Measures: Complications and novel lumbar and nerve pathology were the outcome measures.Methods: Patients undergoing minimally invasive SI fusion from 2007 to 2014 were identified using the Pearl Diver patient record database (Pearl Diver Technologies, West Conshohocken, PA, USA) from the nationwide private insurance provider Humana Inc. This approach provided access to records of over 18 million patients in every major geographic region of the country. Using the ICD-9 diagnosis codes (International Classification of Diseases 9th edition), data from patient records were analyzed to reveal incidence of postoperative infection, pain, osteomyelitis, joint derangement, urinary tract infection, and novel lumbar and nervous system pathology.Results: Four hundred sixty-nine patients (305 female; 164 male) within the Humana insurance database received minimally invasive SI fusion between 2007 and 2014. Data from these patients showed a substantial increase in the use of the procedure over this 7-year period. Among these patients, an overall complication rate of 13.2% (n=62) was seen at 90 days postoperatively and 16.4% (n=77) at 6 months. The number of patients receiving a first time diagnosis of lumbar pathology following minimally invasive SI fusion in the sample population was also analyzed. The incidence of novel lumbar pathology in this population was 3.6% (n=17) at 90 days postoperatively and 5.3% (n=25) at 6 months. Men experienced diagnoses of novel lumbar pathology at higher rates than women within both 90 days (men=6.7%; women≤3.3%) and 6 months (men=9.1%; women≤3.3%) of the procedure (p<.01).Conclusions: The results of this study show that minimally invasive SI joint fusion could possibly carry higher risks of complications than previously stated. These findings are useful for physicians and patients when considering treatment for chronic SI joint pain. [ABSTRACT FROM AUTHOR]

Background Context: Bulging of ligamentum flavum can happen with the aging process and can lead to compression of the spinal cord and nerves. However, the distribution and the risk factors associated with a missed ligamentum flavum bulge (LFB) are unknown.Purpose: The aim was to evaluate the distribution and risk factors associated with missed LFB in the cervical spine.Study Design: This was a retrospective analysis of kinematic magnetic resonance images (kMRI).Patient Sample: Patients diagnosed with symptomatic neck pain or radiculopathy between March 2011 and October 2012 were included.Outcome Measures: The outcome measures were missed LFB and degenerative factors.Methods: A total of 200 patients (1,000 cervical segments) underwent upright kMRI in neutral, flexion, and extension postures. The LFB, sagittal cervical angles, disc herniation, disc degeneration, disc height, angular motion, translational motion, age, and gender were recorded. After excluding segments with LFB in neutral and flexion position, Pearson and Spearman correlation coefficients were used to evaluate the relation between the risk factors and missed LFB in the extension position.Results: The average depth of LFB was 0.24±0.71 mm at C2-C3, 1.02±1.42 mm at C3-C4, 1.65±1.48 mm at C4-C5, 2.13±1.37 mm at C5-C6, and 1.05±1.54 mm at C6-C7. The distribution of LFB was the most frequent at C5-C6 level (76.58%) followed by C4-C5 (63.06%). Disc herniation, disc degeneration, angular variation, and translational motion were significantly correlated with missed LFB at C4-C5 andC5-C6. Disc degeneration was the only factor significantly correlated with missed LFB at all cervical segments.Conclusions: Occurrence and depth of missed LFB was the highest at C4-C5 and C5-C6 compared with other cervical levels. Disc degeneration, disc herniation, angular variation, and translational motion could play a role in the development of LFB at C4-C5 andC5-C6. [ABSTRACT FROM AUTHOR]

Adjacent segment disease (ASD) is a possible complication following lumbar surgeries, particularly lumbar fusion. To investigate the clinical risk factors associated with developing radiological and/or clinical ASD following lumbar fusion. Systematic review and meta-analysis. Adult patients undergoing lumbar fusion. Clinical risk factors associated with the development of ASD. We performed a comprehensive literature search to find the relevant studies using PubMed, Embase, Medline, Scopus, and the Cochrane library databases from the beginning to December 2019. The titles and abstracts were used for initial screening, followed by a full-text review. The methodological index for non‐randomized studies (MINORS) criteria were used to evaluate the methodological quality of the included studies. A meta-analysis was conducted to calculate the odds ratio (OR) with the 95% confidence interval (CI) for dichotomous variables and mean difference (MD) with 95% CI for continuous variables. Both fixed and random-effects models were used to pool the data according to the observed heterogeneity. Thirty-five studies were included in the final qualitative analysis. Twenty-two of these studies were included in the risk factors meta-analyses. The mean quality score of the included studies was 12.4±1.9 (range, 8-16) points, based on the MINORS criteria. The level of evidence was low for many risk factors. Overall, 1,266 (17.2%) patients acquired ASD following lumbar fusion, and 6108 (82.8%) patients did not develop ASD, within a follow-up ranging between 20.5 - 165.6 months. Four clinical variables were found to have statistically significant risk factors for ASD, including higher preoperative body mass index (BMI) (mean difference [MD] = 1.97 kg/m2; 95% confidence interval [CI] = 1.49, 2.45; P < 0.001), floating fusion as compared to lumbosacral fusion (Odds ratio [OR] = 1.78; 95% CI = 1.32,2.41; P <0.001), superior facet joint violation (OR = 10.43; 95% CI = 6.4,17.01; P <0.001), and decompression outside fusion construct (OR = 1.72; 95% CI = 1.25, 2.37; P <0.001). Other factors that were analyzed and were not found to be risk factors for ASD included age (MD = 0.17 years; 95% CI = -0.60,0.94; P = 0.67), gender (OR = 0.91; 95% CI = 0.75,1.11; P = 0.36), smoking (OR = 1.26; 95% CI = 0.94,1.68; P = 0.12), diabetes (OR = 0.73; 95% CI = 0.51,1.05; P = 0.09), hypertension (OR = 1.33; 95% CI = 0.86 , 2.06; P = 0.20), osteoporosis (OR = 1.00; 95% CI = 0.64,1.57; P = 0.99), fusion approach (OR = 1.28; 95% CI = 0.65,2.51; P = 0.48), number of levels (OR = 0.87; 95% CI = 0.50,1.51; P = 0.62), intraoperative blood loss (MD = 12.39; 95% CI = -2.17,26.95; P = 0.10), and operative time (MD = 5.29; 95% CI = -0.15,10.74; P = 0.06). High preoperative BMI, floating fusion, superior facet joint violation, and decompression outside fusion construct are associated with a significant risk of developing ASD in patients undergoing lumbar fusion. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

The concept of frailty has become increasingly recognized, and while patients with cancer are at increased risk for frailty, its influence on perioperative outcomes in metastatic spine tumors is uncertain. Furthermore, the impact of frailty can be confounded by comorbidities or metastatic disease burden. The purpose of this study was to evaluate the influence of frailty and comorbidities on adverse outcomes in the surgical management of metastatic spine disease. Retrospective Cohort Study. A total of 7,772 patients underwent spinal fusion with spinal metastasis within the Nationwide Readmissions Database (NRD). Mortality, medical complications, surgical complications, increased length of stay (LOS), nonroutine discharge and increased costs. A validated binary frailty index (Johns Hopkins Adjusted Clinical Groups) was used to identify frail and non-frail groups, and propensity score-matched analysis (including demographics, comorbidities, surgical and tumor characteristics) was performed. Sub- group analysis of levels involved was performed for cervical, thoracic, lumbar and junctional spine. Outcomes analyzed included mortality, complications, length of stay (LOS), nonroutine discharges and costs. Multivariable-regression techniques were used to develop predictive models for outcomes using frailty and the Elixhauser Comorbidity Index (ECI). A total of 7,772 patients underwent spinal fusion with spinal metastasis, of which 1,974 (25.4%) patients were identified as frail. Following propensity score matching for frail (n= 1,974) and not-frail (n=1,975) groups, frailty demonstrated significantly greater medical complications (OR=1.58; 95% CI 1.33-1.86), surgical complications (OR=1.46; 95% CI 1.15-1.85), LOS (OR=2.65; 95% CI 2.09-3.37), nonroutine discharges (OR=1.79; 95% CI 1.46-2.20) and costs (OR=1.68; 95% CI 1.32-2.14). Differences in mortality were only observed in subgroup analysis and were greater in frail junctional and lumbar spine subgroups. Models using ECI alone (AUC= 0.636-0.788) demonstrated greater predictive ability compared to those using frailty alone (AUC=0.633-0.752). However, frailty combined with ECI improved the prediction of increased LOS (AUC=0.811), cost (AUC=0.768), medical complications (AUC=0.723) and nonroutine discharges (AUC=0.718). Predictive modeling of frailty in subgroups demonstrated the greatest performance for mortality (AUC=0.750) in the lumbar spine, otherwise performed similarly for LOS, costs, complications, and discharge across subgroups. A high prevalence of frailty existed in the current patient cohort. Frailty contributed to worse short-term adverse outcomes and could be more influential in the lumbar and junctional spine due to higher risk of deconditioning in the postoperative period. Predictions for short-term outcomes can be improved by adding frailty to comorbidity indices, suggesting a more comprehensive preoperative risk stratification should include frailty. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Lumbar fusions are commonly used surgical techniques for the treatment of instability and degenerative disc disease. Few studies have examined if the non-opioid analgesics Gabapentin and Pregabalin can effectively manage postoperative pain following common lumbar fusion procedures. This study aims to examine postoperative complications associated with the use of non-opioid analgesics (ie, Gabapentin or Pregabalin) for postoperative pain management following anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), or transforaminal lumbar interbody fusion (TLIF). Retrospective database review. Patient cohort identified using MSpine national database that includes patients of all payer types who received fusion procedures. Complications examined included the following: neurologic, GI, respiratory, DVT and pulmonary embolism, pruritus, mental disorders, urinary incontinence and postoperative pain. The MSpine national database was queried with relevant Current Procedural Terminology (CPT) codes for patients who underwent an ALIF, PLIF, or TLIF between 2010 to 2019. Patients were organized into anterior approach and posterior approach groups and further queried using National Drug Codes (NDC) to form cohorts of patients who received (i) exclusively opioids, or (ii) a mix regimen, for postoperative pain management. A search of relevant International Classification of Diseases (ICD-9 and ICD-10) codes identified the postoperative surgical and medical complications. Propensity score matching for age, gender, and Charlson Comorbidity Index was performed to control for potential confounding factors. Odds ratios and CI will be used to compare postoperative complication rates between the various groups. The anterior_opioids group included 22,581 patients (45.5% male and 54.5% female) and the anterior_mix group included 2,192 patients (37.2% male and 62.8% female). The posterior_opioids group included 22,279 patients (48.0% male and 52.0% female) and the posterior_mix group included 2,677 patients (39.4% male and 60.6% female). After propensity score matching, the anterior groups and posterior groups were 2,182 and 2,671 patients, respectively. The incidence of postoperative pain at 6 weeks was higher in anteriormix (6.0%) than anterior_opioids (3.9%); similarly, this incidence was higher in posterior_mix (8.6%) than posterior_opioids (5.6%). The incidence of mental disorders at 3 weeks was higher in anterior_opioids (6.9%) than anterior_mix (5.8%), while the incidence of GI complications at 3 weeks was lower in anterior_opioids (3.1%) than anterior_mix (3.8%). Respiratory complications at 3 weeks were higher in posterior_mix (2.5%) than posterior_opioids (1.9%). Furthermore, neurologic complications at 3 weeks were higher in posterior_mix (2.3%) than posterior_opioids (1.9%). Patients receiving opioids and Gabapentin or Pregabalin for postoperative pain management following ALIF had higher incidence of postoperative pain and GI complications, but lower incidence of mental disorders, compared to patients who received opioids. Patients who received a mixed regimen for postoperative pain management following PLIF or TLIF were associated with a higher incidence of postoperative pain, respiratory, and neurologic complications. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background context There is a lack of agreement among spine surgeons as to the best surgical treatment modality for many degenerative lumbar diseases. Although there are many studies examining trends in spinal surgery, specific studies reporting the variations in surgical treatment in the United States for these diseases are lacking. Purpose The aim of this study was to analyze trends in lumbar spinal fusion methods for common lumbar pathologies in the United States. Study design/setting National insurance database review: 2004–2009. Patient sample Data is taken from United Healthcare and represents more than 25 million patients. Outcome measures No outcomes were measured in this study. Methods Using a private insurance database, we identified patients who underwent one of five types of instrumented single-level lumbar spinal fusion for the 10 most common primary diagnoses. Surgery rates were reviewed from 2004 to 2009 and were stratified according to patient age, patient gender, and region in the United States. Poisson regression analysis was performed to determine regional and demographic differences in treatment modality. The authors received no funds in support of this work. Results A total of 23,986 patients met our search criteria. Of the five fusion types, posterior lumbar interbody fusion (PLIF) with posterolateral fusion (PLF) was the most common (45%), followed by PLF (19%), anterior lumbar interbody fusion (ALIF, 16%), PLIF (10%), and ALIF with PLF (9%). There was a significant increase in PLIF with PLF (p<.0001), PLIF (p<.0001), PLF (p=.012), ALIF (p<.0001), and ALIF with PLF (p<.0001) from 2004 to 2009. After controlling for gender, there were significant differences between regions for all fusion types (p<.0001). The likelihood of a posterior fusion increased with age. Anterior fusions were more common in the 30- to 49-year-old age range than in patents older than 50. For patients in age groups older than 30, there was an increased number who underwent a circumferential fusion or an ALIF (p<.022). Fusion types were significantly different between genders (p<.026). Both genders had an overall increase in the number of fusions (p<.001) over the time period studied. Conclusions There are large differences in the United States for surgical treatment methods for lumbar spine pathology. These differences are likely multifactorial, with both patient and surgeon traits playing a role. Illustrating these differences will hopefully lead to outcomes research to determine the indications, efficacy, and appropriateness of these surgical methods, an important step on the path toward standardization of care. [ABSTRACT FROM AUTHOR]

Background context The nonunion rate after lumbar spinal fusion is as high as 25%. Recombinant human bone morphogenetic protein 2 (rhBMP2) has been used as a biological adjunct to promote bony fusion. However, recently there have been concerns about BMP2. Oxysterol 133 (Oxy133) has been shown to promote excellent fusion rates in rodent lumbar spine models and offers a potential alternative to rhBMP2. Purpose The purpose of this study was to compare the fusion rate of rhBMP2 and Oxy133 in a randomized controlled trial using a posterolateral lumbar rabbit spinal fusion model. Study design This was a randomized control animal study. Methods Twenty-four male adult white New Zealand rabbits (3–3.5 kg) underwent bilateral posterolateral lumbar spinal fusion at L4–L5. Rabbits were divided into four groups: control (A), 30-μg rhBMP2 (B), 20-mg Oxy133 (C), and 60-mg Oxy133 (D). At 4 weeks, fusion was evaluated by fluoroscopy, and at 8 weeks, the rabbits were sacrificed and fusion was evaluated radiographically, by manual palpation, and with microcomputed tomography. Results Fusion rates by radiographic analysis at 8 weeks were Group A, 40.0%; Group B, 91.7%; Group C, 91.7%; and Group D, 100%. Evaluation of fusion masses by manual palpation of excised spines after sacrifice showed the following fusion rates: Group A, 0%; Group B, 83.3%; Group C, 83.3%; and Group D, 90%. Microcomputed tomography scanning confirmed these findings. Conclusions These findings in a rabbit model demonstrate that both 20- and 60-mg Oxy133 doses promote fusion that is equivalent to fusion induced by 30-μg rhBMP2 and significantly greater than the control group. The present findings confirm that Oxy133 is a promising candidate for therapeutic development as an alternative to rhBMP2 to promote spinal fusion. [ABSTRACT FROM AUTHOR]

Background context Degenerative spondylolisthesis is a common pathologic condition that leads to lumbar instability and significant clinical symptoms. The effect of this pathology on adjacent lumbar motion segments, however, has not yet been studied. Purpose To characterize the motion characteristics of lumbar degenerative spondylolisthesis at both the diseased and adjacent levels in patients with low-grade, single-level lumbar degenerative spondylolisthesis using kinetic magnetic resonance imaging (kMRI). Study design Retrospective study of patient kMRIs. Patient sample One-hundred twelve patient MRIs with low-grade, single-level lumbar spondylolisthesis were included. Outcome measures Angular and translational motion. Methods This study compared 112 patients diagnosed with low-grade (Grade 1 or 2), single-level lumbar degenerative spondylolisthesis at L3–L4, L4–L5, or L5–S1 with 296 control patients without spondylolisthesis. Angular and translational motion were measured using patient kMRIs. The level of slip was graded according to the Meyerding classification system, and disc degeneration was classified according to the Pfirrmann system. Instability was defined as translational motion greater than 4 mm. Results Lumbar hypomobility was often present regardless of the level of degenerative spondylolisthesis. A slip at L3–L4 resulted in the largest decrease in lumbar range of motion. Instability at the diseased level was most common at L3–L4 (36%), followed by L5–S1 (31%) and L4–L5 (30%). Instability at the adjacent segments was most frequent at L4–L5 (49%), followed by L5–S1 (34%) and L3–L4 (23%). Patients with stable spondylolisthesis generally had decreased angular motion at all lumbar levels. Translational motion at the diseased level was consistently increased. Disc degeneration was significantly greater at the level of slip for the L3–L4 and L4–L5 spondylolisthesis groups and equal to the control group in the L5–S1 group. There was no significant difference in disc degeneration at adjacent segments in L3–L4 and L4–L5 degenerative spondylolisthesis patients, but there was a significant decrease with an L5–S1 slip. Conclusions There were a similar percentage of patients in each degenerative spondylolisthesis group with lumbar instability. Angular motion decreased at the diseased level with L3–L4 and L5–S1 spondylolisthesis, but increased with L4–L5 spondylolisthesis. Translational motion, however, increased at the diseased level in all three groups. There was compensatory hypermobility at adjacent levels in patients with unstable spondylolisthesis at L3–L4 and L4–L5, but not at L5–S1. [ABSTRACT FROM AUTHOR]

Background context Bone morphogenetic protein-2 (BMP-2) has been used to successfully promote spine fusion, but side-effects including nerve inflammation have been observed. Purpose To investigate the direct neurotoxic effects of BMP-2 and test the hypotheses that the use of BMP binding proteins, such as secreted phosphoprotein 24 kD (Spp24), can reduce or eliminate these effects. Study design In vitro experiments and in vivo analysis in a rodent model. Methods In vitro, dorsal root ganglion cells were cultured in the presence of BMP-2 with and without Spp24 and calcitonin gene-related peptide and Substance P, markers of neuroinflammation, were measured by immunohistochemistry. In vivo, rats underwent a left-sided laminotomy at L5 to expose the S1 nerve root and were randomized into four different groups according to the intervention at the laminotomy site: collagen sponge only (no BMP-2 or Spp24), BMP-2 in a collagen sponge only, BMP-2 in a collagen sponge+an empty collagen sponge to act as a barrier, and BMP-2 in a collagen sponge+Spp24 in a collagen sponge to act as a barrier. Functional evaluation was done using the Basso, Beattie, and Bresnahan scale and immunohistochemical analyses were performed using calcitonin gene-related peptide and Substance P staining. Results The neuroinflammatory effects of BMP-2 in vitro were ameliorated by the addition of Spp24. Similarly, in vivo, Spp24 reduced the expression of markers on neuroinflammation in animals treated with BMP-2 and also improved the function after BMP-2 administration. Conclusions These results confirm that BMP binding proteins have great potential as adjuvant therapies to limit BMP-2 related side-effects in spine surgery. [ABSTRACT FROM AUTHOR]

Background context There are often multiple surgical treatment options for a spinal pathology. In addition, there is a lack of data that define differences in surgical treatment among surgeons in the United States. Purpose To assess the surgical treatment patterns among neurologic and orthopedic spine surgeons in the United States for the treatment of one- and two-time recurrent lumbar disc herniation. Study design Electronic survey. Patient sample An electronic survey was delivered to 2,560 orthopedic and neurologic surgeons in the United States. Outcome measures The response data were analyzed to assess the differences among respondents over various demographic variables. The probability of disagreement is reported for various surgeon subgroups. Methods A survey of clinical and radiographic case scenarios that included a one- and two-time lumbar disc herniation was electronically delivered to 2,560 orthopedic and neurologic surgeons in the United States. The surgical treatment options were revision microdiscectomy, revision microdiscectomy with in situ fusion, revision microdiscectomy with posterolateral fusion using pedicle screws, revision microdiscectomy with posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), anterior lumbar interbody fusion (ALIF) with percutaneous screws, ALIF with open posterior instrumentation, or none of these. Significance of p=.01 was used to account for multiple comparisons. Results Four hundred forty-five surgeons (18%) completed the survey. Surgeons in practice for 15+ years were more likely to select revision microdiscectomy compared with surgeons with fewer years in practice who were more likely to select revision microdiscectomy with PLIF/TLIF (p<.001). Similarly, those surgeons performing 200+ surgeries per year were more likely to select revision microdiscectomy with PLIF/TLIF than those performing fewer surgeries (p=.003). No significant differences were identified for region, specialty, fellowship training, or practice type. Overall, there was a 69% and 22% probability that two randomly selected spine surgeons would disagree on the surgical treatment of two- and one-time recurrent disc herniations, respectively. This probability of disagreement was consistent over multiple variables including geographic, practice type, fellowship training, and annual case volume. Conclusions Significant differences exist among US spine surgeons in the surgical treatment of recurrent lumbar disc herniations. It will become increasingly important to understand the underlying reasons for these differences and to define the most cost-effective surgical strategies for these common lumbar pathologies as the United States moves closer to a value-based health-care system. [ABSTRACT FROM AUTHOR]

Background context C5 nerve root palsy (C5P) is a relatively rare complication after anterior and posterior cervical decompression surgery that leads to a variety of debilitating symptoms. The precise etiology remains obscure, and a clear understanding of preoperative risk factors for C5P development does not exist. Purpose To determine whether postoperative C5P can be predicted from preoperative anteroposterior diameter (APD), foraminal diameter (FD), and/or cord-lamina angle (CLA). Study design Retrospective review. Patient sample Consecutive patients who underwent either anterior or posterior decompression surgery at C4-C5 for cervical spondylotic myelopathy. Outcome measures Development of C5P. Methods Blinded reviewers retrospectively assessed magnetic resonance images for each included patient's C4-C5 interspace, including the midline APD, the left and right FDs, and the left and right CLA. Multivariable logistic regression was used to model the probability of palsy on the basis of one or more predictors. A jackknife validation was performed to internally validate the model and assess its generalizability. Results A total of 98 patients fit the inclusion criteria; 12% had developed symptoms of C5 palsy postoperatively. Using the three variables in a predictor-model, we found that the odds ratio of having palsy for APD, FD, and CLA was 0.3, 0.02, and 1.4, respectively. For every 1-mm increase in APD and FD, the odds of developing palsy decrease 69% (p<.0001) and decrease 98% (p<.0003), respectively. In contrast, for every 1-degree increase in CLA, the odds of developing palsy increase by 43% (p<.0001). The receiver-operating characteristic curve for this three-variable model predicting development of palsy has an area under the curve (concordance index) of 0.97. After implementing a jackknife validation, the area under the curve was 95%. Conclusions This study is the first to use the combination of APD, FD, and CLA to predict development of postoperative C5 palsy after decompression surgery for patients with spondylotic myelopathy. This prediction formula may allow for better patient selection and to prepare patients that have an increased probability of developing this complication. [ABSTRACT FROM AUTHOR]

Abstract: Background context: Lumbar foraminal stenosis is a common clinical problem and a significant cause of lower extremity radiculopathy. Minimal in vivo data exists quantifying changes in foraminal area (FA) as the spine moves from flexion to extension in the lumbar spine or on the relationship between FA and lumbar segmental angular motion, translational motion (TM), or disc bulge migration. Purpose: To use kinetic magnetic resonance imaging (kMRI) to evaluate changes in dimensions of lumbar neural foramina during weight bearing in neutral, flexion, and extension positions. To evaluate the relationship between foraminal stenosis and lumbar segmental angular motion, TM, and disc bulge migration. Study design: A retrospective radiographic study. Patient sample: Forty-five patients with a mean age of 44 years undergoing kMRI for symptoms of low back pain or radiculopathy. Outcome measures: Magnetic resonance imaging measurements of FA, angular motion, TM, and disc bulge migration. Methods: Kinetic magnetic resonance imaging of the lumbar spine was reviewed in 45 patients with low back pain or radiculopathy, and parasagittal images were evaluated for changes in neural foraminal dimensions in various degrees of motion with weight bearing. The changes in foraminal dimension were correlated to the amount of segmental angular motion, TM, and disc bulge migration at each level. Neural foramina were also assessed qualitatively by Wildermuth criteria. Only those foramina that were clearly visualized with well-defined anatomic boundaries in all three positions were taken into consideration. Patients with previous surgery, tumor, and scoliosis were excluded from the study. Results: There was a significant decrease in the FA from flexion to neutral (p<.05) at all levels except L5–S1 and from neutral to extension at all levels (p<.05). The average percent decrease in FA was 30.0% with the greatest decrease from flexion to extension occurring at L2–L3 (167–107 mm2) and the smallest change occurring at L5–S1 (135–106 mm2) (p<.05). The magnitude of change in FA increased as angular motion at a segment increased. The mean change in FA was 32.3 mm2 when angular motion was less than 5° and was 75.16 mm2 when angular motion exceeded 15°. The extent of disc bulging posteriorly in the neural foramen was also correlated with the reduction in the FA from flexion to extension, but TM had no effect. Conclusions: Foraminal area decreased significantly in extension compared with flexion and neutral on MRI. Lumbar disc bulge migration and angular motion at each level contributed independently to the decrease in FA in extension, whereas TM had no effect on FA. [Copyright &y& Elsevier]

Abstract: Background context: Bone morphogenetic protein (BMP)-2 and BMP-7 are used to enhance bone formation in spine surgery, but the use of these materials is associated with side effects including inflammation, especially in the soft tissues of the neck. Bone morphogenetic protein–binding peptide (BBP) binds BMP-2 and BMP-7 and imparts a "slow-release" property to collagen carrier. Purpose: To test the hypothesis that the addition of BBP will reduce the soft-tissue inflammation induced by the implantation of BMP-2 and BMP-7 on a collagen sponge. Study design/setting: Prospective in vivo rodent model of inflammation. Methods: We implanted six different materials absorbed onto collagen sponges: absorbable collagen sponge (ACS) alone; BBP alone; recombinant human bone morphogenetic protein (rhBMP)-2 alone; rhBMP-2 plus BBP; rhBMP-7 alone; and rhBMP-7 plus BBP. Sponges were implanted bilaterally (subcutaneously [SC] and intramuscularly [IM]) into the backs of rats. Using magnetic resonance imaging, inflammation was assessed in terms of soft-tissue edema volume at 3 hours and at 2, 4, and 7 days. The animal subjects were killed on Day 7, and the dimensions of the inflammatory mass were measured manually in the case of SC tissue and those of the inflammatory zone were determined subsequently by microscopic examination in the case of muscle. Results: Both the SC and the IM soft-tissue edema volumes in the rhBMP-2 plus BBP and the rhBMP-7 plus BBP groups were significantly lower than those observed in the rhBMP-2 alone and rhBMP-7 alone groups. The edema volume associated with BBP alone was greater than that associated with ACS alone but less than that associated with the other treatment groups. The measurements of inflammatory masses and zone yielded similar results. Conclusions: Bone morphogenetic protein–binding peptide may reduce the inflammatory response associated with the use of rhBMP-2 and rhBMP-7 in a rodent model of inflammation and in a form that has previously been shown to enhance the activity of BMPs. These preliminary studies suggest that BBP may have the potential to be used in the future to improve healing and reduce soft-tissue swelling in surgical applications of BMPs. [Copyright &y& Elsevier]

Abstract: Background context: The rat caudal disc has been increasingly used in studying of disc degeneration because of its simplicity, low cost, and efficiency. However, the reproducibility and standardization are essential to facilitate the investigations of biologic therapeutics at different stages of degeneration. Purpose: To identify the effect of different needle gauges to the degenerative response in rat caudal discs and to examine its pathogenesis by looking at the cellular and matrix changes. Study design: In vivo study of injury-induced rat caudal disc degeneration using needle puncture. Patient sample: Thirty-six Lewis rats aged 12–14 weeks. Outcome measures: The induced degenerative discs were analyzed by plain radiograph, magnetic resonance imaging (MRI) and histological examination. Proteoglycan content was assessed by alcian blue stain. Immunohistochemistry using aggrecan, collagen II, and Sox-9 was also evaluated to investigate cell differentiation and matrix changes. Methods: All rats were divided into three groups according to different needle gauges (18G, 20G, and 22G). Caudal discs were punctured percutaneously under image guidance. Radiographs and MRI were obtained at 2 weeks interval until 8 weeks. At each time point, three rats from each group were sacrificed for histological analysis and immunohistochemistry. Results: Larger needle gauges, especially 18G, produced more deterioration of the disc when compared with smaller sizes, particularly with time. Significant differences were identified in almost all parameters compared between 18G and 22G at the 8-week time point. For the effect of time in the same needle size, the differences occurred between 2- or 4-week and 8-week time point in the 18G and 20G groups. The proteoglycan and aggrecan stain gradually decreased over time. Chondrogenic differentiation was identified within the degenerative disc by detecting Sox-9 positive cells and collagen II accumulation increased as degeneration progressed. Conclusions: The puncture-induced degenerative changes in rat caudal discs can imitate the human degenerative cascade as observed in plain radiograph, MRI, histology, and immunohistochemistry. We suggest that needle size affects the occurrence of progression of degeneration; thus, the large needle size was required to accelerate the deterioration. The size of needle and time point after injury should be considered when investigating the effect of therapeutic materials to retard degeneration or regenerate the intervertebral disc. [Copyright &y& Elsevier]