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Hounsfield units (HU), typically measured at L1-L2, have been identified as a surrogate marker for lumbar Bone Mineral Density (BMD). However, concern remains that L1-L2 BMD may not fully capture BMD differences throughout the lumbosacral spine and inadvertently provide inaccurate assessment. To evaluate the impact of how conventional HU evaluation relates to local HU at commonly instrumented levels, and to evaluate the impact of age and postmenopausal state on HU in the lumbar spine. Cross sectional comparative study. Consecutive female patients presenting to a spine clinic between April 2017 and January 2019 who underwent lumbar CT were selected. Previous lumbar surgery, tumor, fracture or infection were excluded. HU were assessed on lumbar CT by placing an elliptical region of interest confined to the medullary space of the vertebral body, and avoiding cortical bone or sclerosis. HU measurements were performed for L1-S1 in 7 regions of each vertebral body: mid-sagittal; axial-superior, waist, inferior; axial at the waist–anterior, middle, posterior. Patients were divided based on whether they were pre- or postmenopausal. HU were compared between the pre- and postmenopausal cohorts using student t-test or Mann-Whitney u-test. The difference between routinely used L1-L2 average HU and local HU in each region was calculated and compared between groups. Association of age and menopausal state with HU was assessed using regression analyses. Forty-eight patients, 18 premenopausal and 30 postmenopausal were included. The postmenopausal group was significantly older (67 versus 41 years; p<0.0001). Postmenopausal women had lower HU in all regions at all levels (p<0.05), with the mean difference ranging from 45 to 90 HU. Depending on the region, the L1-L2 average was more than 10 units greater than L4 in 30–70% of premenopausal and 40–70% of postmenopausal women (p>0.05). L1-L2 average was also more than 10 units greater than L5 measurements in 17–78% of premenopausal and 40–70% of postmenopausal women (p>0.05, except sagittal region p=0.038). Age, but not BMI showed a significant negative correlation with HU, which was strong in premenopausal and moderate in postmenopausal women. Age and menopausal state account for 35-60% of the variability in HU, except in the posterior region, where they account for 25-45%. Age and postmenopausal state were negatively associated with HU in the lumbosacral spine, and the conventionally used L1-L2 average did not adequately capture local HU variations. Local BMD assessment using HU may provide a more accurate assessment of morphometric characteristics and trabecular milieu in the operative region. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Bone density in the lumbar spine is variable by level and can impact surgical strategy. In the cervical spine, low Hounsfield units (HU) have been associated with cage subsidence. The distribution of HU in the cervical spine has not been established. To define level-specific cervical HU reference values and the relationship between cervical bone density, age, BMI, comorbidities and alignment. Retrospective review at a single center from May 2015 to December 2019. A total of 224 patients, 18 excluded for previous hardware and 5 for known osteoporosis. Hounsfield units. Patients who presented with neck symptoms and had a cervical spine CT for evaluation of pathology or surgical planning were included. Exclusions were hardware on CT, osteoporosis, or cervical deformity. Measurements were performed in 5 regions of each vertebral body (VB) (C2-T1; mid-axial, anterior-axial, posterior-axial, mid-coronal, and mid-sagittal) and 2 regions of the lateral masses (LMs) (C3-C6; mid-cor, mid-sag). The VB measurements were averaged at each level to obtain a composite value of each vertebral body (TotalVB), similarly the mid-cor and mid-sag values were averaged at each LM (TotalLatM). Outliers were excluded pairwise. To evaluate reliability, 6 observers each measured 355 HU values (71 over 5 patients), inter-relater reliability assessed with intraclass correlation coefficients (ICCs). Correlations of composite HU with age, BMI, Charlston Comorbidity Index (CCI) and cervical alignment were evaluated. Average age 57±12 years, mean BMI 28±6 kg/m2, 63.5% male, 90.1% white. Diagnoses included radiculopathy (45.8%), myelopathy (37.9%) and facet arthropathy (46.3%). ICC for HU measurements were as follows: VB, 0.82 mid-axial, 0.59 ant-axial, 0.77 post-axial, 0.88 mid-cor, 0.88 mid-sag; LM, 0.46 mid-sag, 0.61 mid-cor. C4 VB and C4 LM had the highest HU (383.6±71.9 and 480.0±103, respectively) while T1 VB and C6 LM had the lowest (232.3±46.5 and 398.3±98.2, respectively). No significant correlations were found between LM HU and age, BMI, CCI, or alignment. Increased kyphosis was weakly correlated with VB HU at all levels (except C2) strongest correlations at C7 (0.25) and weakest correlation at C3 (0.16). Age and CCI showed weak-moderate correlations with VB HU at all levels (age, r= -0.20 to -0.35; CCI r= -0.28 [C2, C7, T1] to -0.17 [C4]). Our level-specific cervical HU values may be referenced when evaluating cervical BMD. The most reliable measurement technique is on the mid-sag or mid-cor VB, measurement of LMs is less reliable. Bone is least dense in the lower cervical spine, which may influence instrumentation strategies. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Telehealth use in spine surgery has become widespread due to the COVID-19 pandemic. The degree of global adoption remains unknown. To our knowledge, this is the first global survey to directly evaluate provider perspectives surrounding telemedicine use-cases. To elicit the extent of adoption of international spine telehealth. We aimed to explore telemedicine platform used, ease of use, and acceptable use-cases. Cross-sectional email survey, international. Spine Surgeons. Perspectives and practices of spine telemedicine. An anonymous, cross-sectional email survey was sent to the members of AO Spine. Survey questions covered provider experiences with and perceptions of telemedicine. Descriptive statistics were used to depict responses and responses were compared amongst regions. A total of 485 spine providers responded to the survey. As of May 2020, telemedicine usage comprised >39.0% of all visits — up from <10.0% of visits pre-pandemic. A majority of providers (60.5%) performed at least 1 telemedicine visit. The format of "telemedicine" varied widely by region: African (45.2%) and European (50.0%) providers were more likely to use phone calls (no video), whereas North (66.7%) and South American (77.0%) surgeons more commonly used audio-visual telemedicine (p<0.001). North American providers used telemedicine the most during COVID-19 (>60.0% of all visits). There were 81.9% of all providers who "agreed/strongly agreed" telemedicine was easy to use. Respondents tended to "agree" that imaging review, the initial appointment, and postoperative care could be performed using telemedicine. Almost all (95.4%) surgeons preferred at least one in-person visit prior to the day of surgery. Our study noted significant geographical differences in the rate of telemedicine usage and the platform of telemedicine utilized. Spine surgeons found telemedicine feasible for imaging review, initial visits, and follow-up visits although the vast majority still preferred at least one in-person preoperative visit. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Hounsfield units (HU), typically measured at L1-L2, have been identified as a surrogate marker for lumbar Bone Mineral Density (BMD). However, concern remains that L1-L2 BMD may not fully capture BMD differences throughout the lumbosacral spine and inadvertently provide inaccurate assessment. To evaluate the impact of age, gender and BMI on lumbar HU, compare the conventional L1-L2 HU measurements with the common levels of degenerative pathology, compare HU measurements among different vertebral levels and evaluate the distribution of HU within the individual vertebral bodies. Cross sectional study. Consecutive patients presenting to a spine clinic between April2017 and January 2019 who underwent lumbar CT were selected. Previous lumbar surgery, tumor, fracture or infection were excluded. HU measurements performed in 7 regions of each vertebral body: Mid-sagittal; Axial–Superior, Waist, Inferior; Axial at the waist–Anterior, Middle, Posterior. Association with age and BMI was evaluated using Pearson product-moment correlation. The difference between L1-L2 and L4 and L5 HU was assessed. Comparison of HU amongst levels and within each level was performed using ANOVA and paired t-tests. A total of 100 patients (mean age=56years, BMI=26.4 kg/m2, 48% males) were included. Age showed a negative correlation with HU in all regions at all levels (p<0.0001). BMI and gender did not show an association with HU. Conventional L1-L2 HU overestimated L4 and L5 HU by at least 10 units in 32–67% of patients, depending on the region. S1 demonstrated higher HU than L3 (p=0.025) and L4 (p=0.029) in the mid-sagittal plane, and higher HU than all other levels in the Superior (p<0.0001) and Waist [overall (p<0.0001), and anterior (p<0.0001), middle (p<0.0001) and posterior (p<0.0001 to p=0.016)] regions in the axial plane, with no other between-level differences. From L1 to L4, HU in the Superior region was significantly lower than that in the Inferior region (p<0.0001 to p=0.003). The opposite was seen at S1, with a decrease in HU from Superior to Waist to Inferior (p<0.0001). At all levels, HU was lower in the Posterior region compared to the Anterior and Middle (p<0.001), with no difference between Anterior and Middle (p>0.05). Although BMD at L1-L2 is often used as a marker of lumbosacral BMD, it may overestimate BMD of other levels. Furthermore, all levels demonstrated differences among various regions. These findings suggest the need for more detailed BMD estimation, especially in patients undergoing spinal instrumentation in whom variations in local BMD can be used to guide surgical planning and could potentially impact clinical outcomes. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]