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1.
Global Spine J ; : 21925682221131540, 2022 Sep 29.
Article in English | MEDLINE | ID: mdl-36176014

ABSTRACT

STUDY DESIGN: Survey. OBJECTIVE: In March of 2020, an original study by Louie et al investigated the impact of COVID-19 on 902 spine surgeons internationally. Since then, due to varying government responses and public health initiatives to the pandemic, individual countries and regions of the world have been affected differently. Therefore, this follow-up study aimed to assess how the COVID-19 impact on spine surgeons has changed 1 year later. METHODS: A repeat, multi-dimensional, 90-item survey written in English was distributed to spine surgeons worldwide via email to the AO Spine membership who agreed to receive surveys. Questions were categorized into the following domains: demographics, COVID-19 observations, preparedness, personal impact, patient care, and future perceptions. RESULTS: Basic respondent demographics, such as gender, age, home demographics, medical comorbidities, practice type, and years since training completion, were similar to those of the original 2020 survey. Significant differences between groups included reasons for COVID testing, opinions of media coverage, hospital unemployment, likelihood to be performing elective surgery, percentage of cases cancelled, percentage of personal income, sick leave, personal time allocation, stress coping mechanisms, and the belief that future guidelines were needed (P<.05). CONCLUSION: Compared to baseline results collected at the beginning of the COVID-19 pandemic in 2020, significant differences in various domains related to COVID-19 perceptions, hospital preparedness, practice impact, personal impact, and future perceptions have developed. Follow-up assessment of spine surgeons has further indicated that telemedicine and virtual education are mainstays. Such findings may help to inform and manage expectations and responses to any future outbreaks.

2.
Global Spine J ; 12(2): 249-262, 2022 Mar.
Article in English | MEDLINE | ID: mdl-32762354

ABSTRACT

STUDY DESIGN: Cross-sectional observational cohort study. OBJECTIVE: To investigate preparation, response, and economic impact of COVID-19 on private, public, academic, and privademic spine surgeons. METHODS: AO Spine COVID-19 and Spine Surgeon Global Impact Survey includes domains on surgeon demographics, location of practice, type of practice, COVID-19 perceptions, institutional preparedness and response, personal and practice impact, and future perceptions. The survey was distributed by AO Spine via email to members (n = 3805). Univariate and multivariate analyses were performed to identify differences between practice settings. RESULTS: A total of 902 surgeons completed the survey. In all, 45.4% of respondents worked in an academic setting, 22.9% in privademics, 16.1% in private practice, and 15.6% in public hospitals. Academic practice setting was independently associated with performing elective and emergent spine surgeries at the time of survey distribution. A majority of surgeons reported a >75% decrease in case volume. Private practice and privademic surgeons reported losing income at a higher rate compared with academic or public surgeons. Practice setting was associated with personal protective equipment availability and economic issues as a source of stress. CONCLUSIONS: The current study indicates that practice setting affected both preparedness and response to COVID-19. Surgeons in private and privademic practices reported increased worry about the economic implications of the current crisis compared with surgeons in academic and public hospitals. COVID-19 decreased overall clinical productivity, revenue, and income. Government response to the current pandemic and preparation for future pandemics needs to be adaptable to surgeons in all practice settings.

4.
Eur Spine J ; 30(8): 2133-2142, 2021 08.
Article in English | MEDLINE | ID: mdl-33452925

ABSTRACT

PURPOSE: The COVID-19 pandemic forced many surgeons to adopt "virtual medicine" practices, defined as telehealth services for patient care and online platforms for continuing medical education. The purpose of this study was to assess spine surgeon reliance on virtual medicine during the pandemic and to discuss the future of virtual medicine in spine surgery. METHODS: A comprehensive survey addressing demographic data and virtual medicine practices was distributed to spine surgeons worldwide between March 27, 2020, and April 4, 2020. RESULTS: 902 spine surgeons representing seven global regions responded. 35.6% of surgeons were identified as "high telehealth users," conducting more than half of clinic visits virtually. Predictors of high telehealth utilization included working in an academic practice (OR = 1.68, p = 0.0015) and practicing in Europe/North America (OR 3.42, p < 0.0001). 80.1% of all surgeons were interested in online education. Dedicating more than 25% of one's practice to teaching (OR = 1.89, p = 0.037) predicted increased interest in online education. 26.2% of respondents were identified as "virtual medicine surgeons," defined as surgeons with both high telehealth usage and increased interest in online education. Living in Europe/North America and practicing in an academic practice increased odds of being a virtual medicine surgeon by 2.28 (p = 0.002) and 1.15 (p = 0.0082), respectively. 93.8% of surgeons reported interest in a centralized platform facilitating surgeon-to-surgeon communication. CONCLUSION: COVID-19 has changed spine surgery by triggering rapid adoption of virtual medicine practices. The demonstrated global interest in virtual medicine suggests that it may become part of the "new normal" for surgeons in the post-pandemic era.


Subject(s)
COVID-19 , Telemedicine , Humans , Pandemics , SARS-CoV-2 , Spine
6.
Global Spine J ; 10(5): 534-552, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32677575

ABSTRACT

STUDY DESIGN: Cross-sectional, international survey. OBJECTIVES: The current study addressed the multi-dimensional impact of COVID-19 upon healthcare professionals, particularly spine surgeons, worldwide. Secondly, it aimed to identify geographical variations and similarities. METHODS: A multi-dimensional survey was distributed to surgeons worldwide. Questions were categorized into domains: demographics, COVID-19 observations, preparedness, personal impact, patient care, and future perceptions. RESULTS: 902 spine surgeons representing 7 global regions completed the survey. 36.8% reported co-morbidities. Of those that underwent viral testing, 15.8% tested positive for COVID-19, and testing likelihood was region-dependent; however, 7.2% would not disclose their infection to their patients. Family health concerns were greatest stressor globally (76.0%), with anxiety levels moderately high. Loss of income, clinical practice and current surgical management were region-dependent, whereby 50.4% indicated personal-protective-equipment were not adequate. 82.3% envisioned a change in their clinical practice as a result of COVID-19. More than 33% of clinical practice was via telemedicine. Research output and teaching/training impact was similar globally. 96.9% were interested in online medical education. 94.7% expressed a need for formal, international guidelines to manage COVID-19 patients. CONCLUSIONS: In this first, international study to assess the impact of COVID-19 on surgeons worldwide, we identified overall/regional variations and infection rate. The study raises awareness of the needs and challenges of surgeons that will serve as the foundation to establish interventions and guidelines to face future public health crises.

7.
Neurospine ; 17(2): 313-330, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32615695

ABSTRACT

OBJECTIVE: To determine if personal health of spine surgeons worldwide influences perceptions, healthcare delivery, and decision-making during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: A cross-sectional study was performed by distributing a multidimensional survey to spine surgeons worldwide. Questions addressed demographics, impacts and perceptions of COVID-19, and the presence of surgeon comorbidities, which included cancer, cardiac disease, diabetes, obesity, hypertension, respiratory illness, renal disease, and current tobacco use. Multivariate analysis was performed to identify specific comorbidities that influenced various impact measures. RESULTS: Across 7 global regions, 36.8% out of 902 respondents reported a comorbidity, of which hypertension (21.9%) and obesity (15.6%) were the most common. Multivariate analysis noted tobacco users were more likely to continue performing elective surgery during the pandemic (odds ratio [OR], 2.62; 95% confidence interval [CI], 1.46-4.72; p = 0.001) and were less likely to utilize telecommunication (OR, 0.51; 95% CI, 0.31-0.86; p = 0.011), whereas those with hypertension were less likely to warn their patients should the surgeon become infected with COVID-19 (OR, 0.57; 95% CI, 0.37-0.91; p = 0.017). Clinicians with multiple comorbidities were more likely to cite personal health as a current stressor (OR, 1.32; 95% CI, 1.07-1.63; p = 0.009) and perceived their hospital's management unfavorably (OR, 0.74; 95% CI, 0.60-0.91; p = 0.005). CONCLUSION: This is the first study to have mapped global variations of personal health of spine surgeons, key in the development for future wellness and patient management initiatives. This study underscored that spine surgeons worldwide are not immune to comorbidities, and their personal health influences various perceptions, healthcare delivery, and decision-making during the COVID-19 pandemic.

8.
Spine J ; 20(7): 998-1024, 2020 07.
Article in English | MEDLINE | ID: mdl-32333996

ABSTRACT

BACKGROUND CONTEXT: The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016. PURPOSE: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. STUDY DESIGN: This is a guideline summary review. METHODS: This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors. RESULTS: Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. CONCLUSIONS: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx.


Subject(s)
Low Back Pain , Evidence-Based Medicine , Humans , Low Back Pain/diagnosis , Low Back Pain/therapy , Spine
9.
JOR Spine ; 3(4): e1122, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33392457

ABSTRACT

BACKGROUND: The COVID-19 pandemic has impacted spine care around the globe. Much uncertainty remains regarding the immediate and long-term future of spine care and education in this COVID-19 era. STUDY DESIGN: Cross-sectional, international study of spine surgeons. METHODS: A multi-dimensional survey was distributed to spine surgeons around the world. A total of 73 questions were asked regarding demographics, COVID-19 observations, personal impact, effect on education, adoption of telemedicine, and anticipated challenges moving forward. Multivariate analysis was performed to assess factors related to likelihood of future conference attendance, future online education, and changes in surgical indications. RESULTS: A total of 902 spine surgeons from seven global regions completed the survey. Respondents reported a mean level of overall concern of 3.7 on a scale of one to five. 84.0% reported a decrease in clinical duties, and 67.0% reported a loss in personal income. The 82.5% reported being interested in continuing a high level of online education moving forward. Respondents who personally knew someone who tested positive for COVID-19 were more likely to be unwilling to attend a medical conference 1 year from now (OR: 0.61, 95% CI: [0.39, 0.95], P = .029). The 20.0% reported they plan to pursue an increased degree of nonoperative measures prior to surgery 1 year from now, and respondents with a spouse at home (OR: 3.55, 95% CI: [1.14, 11.08], P = .029) or who spend a large percentage of their time teaching (OR: 1.45, 95% CI: [1.02, 2.07], P = .040) were more likely to adopt this practice. CONCLUSIONS: The COVID-19 pandemic has had an adverse effect on surgeon teaching, clinical volume, and personal income. In the future, surgeons with family and those personally affected by COVID-19 may be more willing to alter surgical indications and change education and conference plans. Anticipating these changes may help the spine community appropriately plan for future challenges.

10.
Spine J ; 16(12): 1478-1485, 2016 12.
Article in English | MEDLINE | ID: mdl-27592807

ABSTRACT

BACKGROUND CONTEXT: The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adult Isthmic Spondylolisthesis features evidence-based recommendations for diagnosing and treating adult patients with isthmic spondylolisthesis. The guideline is intended to reflect contemporary treatment concepts for symptomatic isthmic spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of June 2013. NASS' guideline on this topic is the only guideline on adult isthmic spondylolisthesis accepted in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse. PURPOSE: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with isthmic spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. STUDY DESIGN: This is a guideline summary review. METHODS: This guideline is the product of the Adult Isthmic Spondylolisthesis Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questionsto address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Adult Isthmic Spondylolisthesis guideline was accepted into the National Guideline Clearinghouse and will be updated approximately every 5 years. RESULTS: Thirty-one clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. CONCLUSIONS: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with isthmic spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.


Subject(s)
Evidence-Based Medicine/methods , Practice Guidelines as Topic , Spondylolisthesis/diagnosis , Adult , Evidence-Based Medicine/standards , Humans , Neurosurgery/organization & administration , Societies, Medical , Spondylolisthesis/therapy , United States
11.
Neurosurgery ; 77 Suppl 4: S33-45, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26378356

ABSTRACT

Vertebral compression fractures (VCFs) are the most common type of fracture secondary to osteoporosis. These fractures are associated with significant rates of morbidity and mortality and annual direct medical expenditures of more than $1 billion in the United States. Although many patients will respond favorably to nonsurgical care of their VCF, contemporary natural history data suggest that more than 40% of patients may fail to achieve significant pain relief within 12 months of symptom onset. As a result, percutaneous vertebral augmentation is often used to hasten symptom resolution and return of function. However, controversy regarding the role of kyphoplasty and vertebroplasty in the treatment of symptomatic VCFs exists. The purposes of this review are (1) to outline the epidemiology of VCFs as well as the physical morbidity and economic impact of these injuries, (2) to familiarize the reader with the best available evidence surrounding the operative and nonoperative treatment of VCFs, and (3) to examine the literature pertaining to the cost-effectiveness of surgical management of VCFs with the overarching goal of helping physicians make informed decisions regarding symptomatic VCF treatment.


Subject(s)
Fractures, Compression/therapy , Kyphoplasty/methods , Osteoporotic Fractures/therapy , Spinal Fractures/therapy , Aged , Female , Fractures, Compression/economics , Fractures, Compression/epidemiology , Humans , Osteoporosis , Osteoporotic Fractures/economics , Osteoporotic Fractures/epidemiology , Pain Management , Spinal Fractures/economics , Spinal Fractures/epidemiology , Treatment Outcome , United States/epidemiology , Vertebroplasty/methods
14.
Orthopedics ; 35(3): 224-5, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22385600
16.
Int J Biomater ; 2011: 467641, 2011.
Article in English | MEDLINE | ID: mdl-21941551

ABSTRACT

Aim. Physicochemical mechanical and in vitro biological properties of novel formulations of polymeric calcium phosphate cements (CPCs) were investigated. Methods. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light activated polyalkenoic acid, or polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs. Setting time, compressive and diametral strength of CPCs was compared with zinc polycarboxylate cement (control). Specimens were characterized using X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. In vitro cytotoxicity of CPCs and control was assessed. Results. X-ray diffraction analysis showed hydroxyapatite, monetite, and brushite. Acid-base reaction was confirmed by the appearance of stretching peaks in IR spectra of set cements. SEM revealed rod-like crystals and platy crystals. Setting time of cements was 5-12 min. Type III showed significantly higher strength values compared to control. Type III yielded high biocompatibility. Conclusions. Type III CPCs show promise for dental applications.

17.
Spine (Phila Pa 1976) ; 36(21 Suppl): S87-95, 2011 Oct 01.
Article in English | MEDLINE | ID: mdl-21897346

ABSTRACT

STUDY DESIGN: Systematic review of literature focused on heterogeneity of treatment effect analysis. OBJECTIVE: The objectives of this systematic review were to determine if comorbid disease and general health factors modify the effect of fusion versus nonoperative management in chronic low back pain (CLBP) patients? SUMMARY OF BACKGROUND DATA: Surgical fusion as a treatment of back pain continues to be controversial due to inconsistent responses to treatment. The reasons for this are multifactorial but may include heterogeneity in the patient population and in surgeon's attitudes and approaches to this complex problem. There is a relative paucity of high quality publications from which to draw conclusions. We were interested in investigating the possibility of detecting treatment response differences comparing fusion to conservative management for CLBP among subpopulations with different disease specific and general health risk factors. METHODS: A systematic search was conducted in MEDLINE and the Cochrane Collaboration Library for literature published from 1990 through December 2010. To evaluate whether the effects of CLBP treatment varied by disease or general health subgroups, we sought randomized controlled trials or nonrandomized observational studies with concurrent controls evaluating surgical fusion versus nonoperative management for CLBP. Of the original 127 citations identified, only 5 reported treatment effects (fusion vs. conservative management) separately by disease and general health subgroups of interest. Of those, only two focused on patients who had primarily back pain without spinal stenosis or spondylolisthesis. RESULTS: Few studies comparing fusion to nonoperative management reported differences in outcome by specific disease or general health subpopulations. Among those that did, we observed the effect of fusion compared to nonoperative management was slightly more favorable in patients with no additional comorbidities compared with those with additional comorbidities and more marked in nonsmokers compared with smokers. CONCLUSION: It is unclear from the literature which patients are the best candidates for fusion versus conservative management when experiencing CLBP without significant neurological impairment. Nonsmokers may be more likely to have a favorable surgical fusion outcome in CLBP patients. Comorbid disease presence has not been shown to definitively modify the effect of fusion. Further prospective studies that are designed to evaluate these and other subgroup effects are encouraged to confirm these findings. CLINICAL RECOMMENDATIONS: We recommend optimizing the management of medical co-morbidities and smoking cessation before considering surgical fusion in CLBP patients. Strength of recommendation: Weak.


Subject(s)
Chronic Pain/therapy , Health Status , Low Back Pain/therapy , Spinal Fusion , Chronic Pain/diagnosis , Chronic Pain/epidemiology , Chronic Pain/surgery , Comorbidity , Evidence-Based Medicine , Humans , Low Back Pain/diagnosis , Low Back Pain/epidemiology , Low Back Pain/surgery , Patient Selection , Practice Guidelines as Topic , Risk Assessment , Risk Factors , Smoking/epidemiology , Spinal Fusion/adverse effects , Treatment Outcome
18.
Int J Biomater ; 20102010.
Article in English | MEDLINE | ID: mdl-20811498

ABSTRACT

New polymeric calcium phosphate cement composites (CPCs) were developed. Cement powder consisting of 60 wt% tetracalcium phosphate, 30 wt% dicalcium phosphate dihydrate, and 10 wt% tricalcium phosphate was combined with either 35% w/w poly methyl vinyl ether maleic acid or polyacrylic acid to obtain CPC-1 and CPC-2. The setting time and compressive and diametral tensile strength of the CPCs were evaluated and compared with that of a commercial hydroxyapatite cement. In vitro cytotoxicity and in vivo biocompatibility of the two CPCs and hydroxyapatite cement were assessed. The setting time of the cements was 5-15 min. CPC-1 and CPC-2 showed significantly higher compressive and diametral strength values compared to hydroxyapatite cement. CPC-1 and CPC-2 were equivalent to Teflon controls after 1 week. CPC-1, CPC-2, and hydroxyapatite cement elicited a moderate to intense inflammatory reaction at 7 days which decreased over time. CPC-1 and CPC-2 show promise for orthopedic applications.

19.
J Biomed Mater Res B Appl Biomater ; 93(2): 297-303, 2010 May.
Article in English | MEDLINE | ID: mdl-20235188

ABSTRACT

Few published studies describe the biological properties of calcium phosphate cements (CPCs) for dental applications. We measured several biologically relevant properties of 3 CPCs over an extended (8 wk) interval. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light-activated modified polyalkenoic acid, or 35% w/w polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs, respectively. Set cements were placed in direct contact with L929 fibroblasts for up to 8 weeks. Media Ca(+2) and pH were determined by atomic absorption spectroscopy and pH electrode respectively. Cell mitochondrial function was measured by MTT assay. Type I cements suppressed mitochondrial activity > 90% (vs. Teflon controls), but significantly (p < 0.05) improved to control levels over 8 weeks. Type II cements suppressed mitochondrial activity > 90% at all times. Type III cements elevated mitochondrial activity significantly after 7 wks. The pH profiles approached neutrality by 24 h, and all cements released calcium into the storage medium at all periods (24 h - 8 wk). We concluded that several types of cements had long-term biological profiles that show promise for dental applications.


Subject(s)
Calcium Phosphates/pharmacology , Calcium/analysis , Dental Cements/pharmacology , Fibroblasts/metabolism , Materials Testing , Animals , Calcium/metabolism , Calcium Phosphates/chemistry , Cell Line , Dental Cements/chemistry , Fibroblasts/cytology , Hydrogen-Ion Concentration , Mice , Mitochondria/metabolism , Time Factors
20.
Spine (Phila Pa 1976) ; 33(22): E828-35, 2008 Oct 15.
Article in English | MEDLINE | ID: mdl-18923306

ABSTRACT

STUDY DESIGN: Biomechanical assessment using calf lumbar motion segments. OBJECTIVE: To determine whether facetectomy affects the primary stability of posterior lumbar interbody fusion. SUMMARY OF BACKGROUND DATA: To improve visualization and access to the disc space, the facet joints frequently are removed. Previous biomechanical studies have indicated a fundamental role for the facet joints in maintaining spinal segment stability. METHODS: Single motion segments from calf lumbar spines were tested for pure-moment flexibility in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). After testing intact, an interbody cage and pedicle screw system were implanted. Next, a bilateral facetectomy was performed, and finally a crosslink was added. Flexibility testing was repeated at each stage of implantation. Data are reported for range of motion (ROM), neutral zone (NZ), and a new compliance parameter (COM), based on the slopes of the moment-angle curve in the neutral and elastic regions. RESULTS: With posterior lumbar interbody fusion implantation, ROM in FE was reduced 82% +/- 4% (mean +/- standard deviation) and NZ 78% +/- 7% over intact (P < 0.015: Wilcoxon). Reduction in LB was slightly more, whereas reduction in AR was considerably less and did not achieve statistical significance for NZ. After facetectomy, ROM in FE increased 0.3 degrees (P < 0.05), on average, and NZ did not change. In LB neither changed significantly. In AR, ROM increased 0.6 degrees (P < 0.05), and NZ increased 0.2 degrees (P < 0.05). The addition of a crosslink changed ROM and NZ less than 0.1 degrees in FE and LB, whereas in AR it restored half of the stability lost due to facetectomy in ROM (P < 0.05), and had a similar trendwise effect on NZ. The new compliance measure, COM, was found to agree with the direction of change in ROM more consistently than did NZ. CONCLUSION: Facetectomy causes a nominal increase in ROM and NZ in FE and LB, which are not affected by the addition of a crosslink. Although the effect of facetectomy is greater in AR-and crosslink has a measurable restoring effect-all differences are within a few tenths of a degree under this loading paradigm. Thus, the clinical utility of adding a crosslink may not be justified based on these small biomechanical changes. COM can serve as a complement to ROM and NZ, or even as a surrogate when its 2 components are reported together, as it shows strong agreement with ROM, effectively distinguishes between lax and elastic region behaviors, and provides a measure of flexibility independent of the load range.


Subject(s)
Lumbar Vertebrae/surgery , Spinal Fusion , Zygapophyseal Joint/surgery , Animals , Biomechanical Phenomena , Bone Screws , Cattle , Elasticity , Internal Fixators , Range of Motion, Articular , Spinal Fusion/instrumentation
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