The impact of degenerative disc disease on regional volumetric bone mineral density (vBMD) measured by quantitative computed tomography

Association between skin ultrasound parameters and revision surgery after posterior spinal fusion

PURPOSE

The literature is scarce in exploring the role of imaging parameters like ultrasound (US) as a biomarker for surgical outcomes. The purpose of this study is to investigate the associations between skin US parameters and revision surgery following spine lumbar fusion.

METHODS

Posterior lumbar fusion patients with 2-years follow-up were assessed. Previous fusion or revision not due to adjacent segment disease (ASD) were excluded. Revisions were classified as cases and non-revision were classified as controls. US measurements conducted at two standardized locations on the lumbar back. Skin echogenicity of the average dermal (AD), upper 1/3 of the dermal (UD), lower 1/3 of the dermal (LD), and subcutaneous layer were measured. Echogenicity was calculated with the embedded echogenicity function of our institution's imaging platform (PACS). Statistical significance was set at p < 0.05.

RESULTS

A total of 128 patients (51% female, age 62 [54-72] years) were included in the final analysis. 17 patients required revision surgery. AD, UD, and LD echogenicity showed significantly higher results among revision cases 124.5 [IQR = 115.75,131.63], 128.5 [IQR = 125,131.63] and 125.5 [IQR = 107.91,136.50] compared to the control group 114.3 [IQR = 98.83,124.8], 118.5 [IQR = 109.28,127.50], 114 [IQR = 94.20,126.75] respectively.

CONCLUSION

The findings of this study demonstrate a significant association between higher echogenicity values in different layers of the dermis and requiring revision surgery. The results provide insights into the potential use of skin US parameters as predictors for revision surgery. These findings may reflect underlying alterations in collagen. Further research is warranted to elucidate the mechanisms driving these associations.

Skeletal effects of sleeve gastrectomy, by sex and menopausal status and in comparison to Roux-en-Y gastric bypass surgery

Context

Roux-en-Y gastric bypass (RYGB) has deleterious effects on bone mass, microarchitecture, and strength. Data are lacking on the skeletal effects of sleeve gastrectomy (SG), now the most commonly performed bariatric surgical procedure.

Objective

We examined changes in bone turnover, areal and volumetric bone mineral density (aBMD, vBMD), and appendicular bone microarchitecture and estimated strength after SG. We compared the results to those previously reported after RYGB, hypothesizing lesser effects after SG than RYGB.

Design Setting Participants

Prospective observational cohort study of 54 adults with obesity undergoing SG at an academic center.

Main Outcome Measures

Skeletal characterization with biochemical markers of bone turnover, dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and high-resolution peripheral QCT (HR-pQCT) was performed preoperatively and 6- and 12-months postoperatively.

Results

Over 12 months, mean percentage weight loss was 28.8%. Bone turnover marker levels increased, and total hip aBMD decreased -8.0% (95% CI -9.1%, -6.7%, p<0.01). Spinal aBMD and vBMD declines were larger in postmenopausal women than men. Tibial and radial trabecular and cortical microstructure worsened, as did tibial estimated strength, particularly in postmenopausal women. When compared to data from a RYGB cohort with identical design and measurements, some SG biochemical, vBMD, and radial microstructural parameters were smaller, while other changes were not.

Conclusions

Bone mass, microstructure, and strength decrease after SG. Some skeletal parameters change less after SG than after RYGB, while for others, we find no evidence for smaller effects after SG. Postmenopausal women may be at highest risk of skeletal consequences after SG.

Association between lumbar endplate damage and bone mineral density in patients with degenerative disc disease

BACKGROUND

To explore the independent association between lumbar endplate damage and bone mineral density (BMD) in patients with degenerative disc disease (DDD).

METHODS

This retrospective investigation was based out of a prospectively collected database from the Affiliated Kunshan Hospital of Jiangsu University. Data from 192 DDD patients, collected between December 2018 and January 2022, were chosen for the final analysis. The average total endplate score (TEPS) of lumbar(L) 1-L4 was assessed by magnetic resonance imaging (MRI), and represents the extent of endplate damage. Osteoporosis severity was assessed via the L1-L4 BMD evidenced by dual-energy x-ray absorptiometry (DXA). Other analyzed information included gender, age, body mass index (BMI), and osteophyte score (OSTS). Uni- and multivariate linear regression analyses were employed to evaluate the association between average TEPS and BMD of L1-L4. Moreover, the generalized additive model (GAM) was employed for non-linear association analysis.

RESULTS

Upon gender, age, BMI, and OSTS adjustments, a strong independent inverse relationship was observed between average TEPS and BMD (β, -0.021; 95% CI, -0.035 to -0.007, P-value = 0.00449). In addition, the gender stratification analysis revealed a linear relationship in males, and a non-linear relationship in females. Specifically, there was a significantly stronger negative relationship between average TEPS and BMD in females, when the average TEPS was < 3.75 (β, -0.063; 95% CI, -0.114 to -0.013; P-value = 0.0157). However, at an average TEPS > 3.75, the relationship did not reach significance (β, 0.007; 95% CI, -0.012 to 0.027; P-value = 0.4592).

CONCLUSIONS

This study demonstrated the independent negative association between average TEPS and BMD values of L1-L4. Upon gender stratification, a linear relationship was observed in males, and a non-linear association in females. The findings reveal that patients with osteoporosis or endplate damage require more detailed examinations and treatment regimen.

The association of lumbar disc degeneration with lumbar vertebral trabecular volumetric bone mineral density in an urban population of young and middle-aged community-dwelling Chinese adults: a cross-sectional study

INTRODUCTION

Lumbar intervertebral disc degeneration (LDD) and osteoporosis (OP) are age-related conditions that induce low back pain and have an impact on quality of life. The relationship between LDD and changes in bone mineral density (BMD) is, however, contentious and ever-changing. The purpose of this study is to investigate the relationship between lumbar vertebral volumetric BMD (vBMD) and LDD in an urban population of young and middle-aged community-dwelling Chinese adults.

MATERIALS AND METHODS

719 participants were recruited from among the subjects enrolled in a 10-year longitudinal study of degeneration of the spine and knee being conducted at the Beijing Jishuitan Hospital. The severity of LDD was graded using the five-grade Pfirrmann classification, and lumbar vertebral vBMD was measured using quantitative computed tomography (QCT). The relationship between the grade of intervertebral disc degeneration and lumbar vertebral vBMD was analyzed, and multiple linear regression was performed to adjust for covariates.

RESULTS

The mean lumbar vBMD decreased as the grade of LDD increased (171.5 g/cm3, 147.8 g/cm3, and 124.3 g/cm3, respectively; P < 0.001). After adjusting for age, a higher LDD stage was associated with a lower mean L2-L4 vBMD, although a statistically significant correlation was observed only in men (standardized coefficient β = - 0.656, P = 0.004). In men, there was a negative correlation between single-vertebra vBMD and degeneration of adjacent intervertebral discs, particularly those involving the L3 vertebra (L2-3 disc: β = - 0.333, P < 0.001, L3-4 disc: β = - 0.398, P < 0.001), as well as the mean grade of the L2-4 discs (β = - 0.448, P < 0.001). However, the L5-S1 disc had a smaller correlation with age than others, and no statistically significant associations with lumbar vBMD were observed in either men (β = - 0.024, P = 0.729) or women (β = - 0.057, P = 0.396).

CONCLUSION

Our study found that the degree of LDD was negatively associated with lumbar trabecular vBMD, although (excepting the L5-S1 disc), the relationship was statistically significant only in men.

The lumbar spinal endplate lesions grades and association with lumbar disc disorders, and lumbar bone mineral density in a middle-young general Chinese population

BACKGROUND

Lumbar vertebral endplates lesions (LEPLs), one of the etiologies of low back pain (LBP), are one of the most prevalent causes of health-care costs. Despite progressively becoming the focus in recent years, almost all studies have concentrated on symptomatic patients rather than general populations. As a result, our study was designed to determine the prevalence and distribution patterns of LEPLs in a middle-young general population, as well as their associations with lumbar disc herniation (LDH), lumbar disc degeneration (LDD), and lumbar vertebral volumetric bone mineral density (vBMD).

METHODS

Seven hundred fifty-four participants aged 20-60 years were recruited from the subjects enrolled in a 10-year longitudinal study of degeneration of the spine and knee being conducted at the Beijing Jishuitan Hospital and 4 of them were excluded due to the missing of MRIs. In this observational study, a lumbar quantitative computed tomography (QCT) and MRI scan were performed among participants within 48 h. T2-weighted sagittal lumbar MRI images for all included subjects were identified for LEPLs by two independent observers based on morphological and local characteristics. Lumbar vertebral vBMD was measured with QCT. The age, BMI, waistline, hipline, lumbar vBMD, LDD, and LDH were measured to investigate their associations with LEPLs.

RESULTS

The prevalence of LEPLs was higher among the male subjects. 80% of endplates were recognition as no lesions with a substantial disparity between female (75.6%) and male subjects (83.4%) (p < 0.001). The most common lesions were "wavy/irregular" and "notched", and "fracture" is most involved in L3-4 inferior endplate both in two genders. LEPLs were found to be associated with LDH (≥ 2 levels: OR = 6.859, P < 0.001; 1 level: OR = 2.328, P = 0.002 in men. OR = 5.004, P < 0.001; OR = 1.805, P = 0.014 in women) reference for non-LDH, and hipline in men (OR = 1.123, P < 0.001).

CONCLUSIONS

LEPLs are the common findings on lumbar MRIs in general population, particularly in men. The presence of these lesions and advance from slightly to severely could be mainly attributed to LDH and men's higher hipline.

Increased risks of vertebral fracture and reoperation in primary spinal fusion patients who test positive for osteoporosis by Biomechanical Computed Tomography analysis

BACKGROUND CONTEXT

While osteoporosis is a risk factor for adverse outcomes in spinal fusion patients, diagnosing osteoporosis reliably in this population has been challenging due to degenerative changes and spinal deformities. Addressing that challenge, biomechanical computed tomography analysis (BCT) is a CT-based diagnostic test for osteoporosis that measures both bone mineral density and bone strength (using finite element analysis) at the spine; CT scans taken for spinal evaluation or previous care can be repurposed for the analysis.

PURPOSE

Assess the effectiveness of BCT for preoperatively identifying spinal fusion patients with osteoporosis who are at high risk of reoperation or vertebral fracture.

STUDY DESIGN

Observational cohort study in a multi-center integrated managed care system using existing data from patient medical records and imaging archives.

PATIENT SAMPLE

We studied a randomly sampled subset of all adult patients who had any type of primary thoracic (T4 or below) or lumbar fusion between 2005 and 2018. For inclusion, patients with accessible study data needed a preop CT scan without intravenous contrast that contained images (before any instrumentation) of the upper instrumented vertebral level.

OUTCOME MEASURES

Reoperation for any reason (primary outcome) or a newly documented vertebral fracture (secondary outcome) occurring up to 5 years after the primary surgery.

METHODS

All study data were extracted using available coded information and CT scans from the medical records. BCT was performed at a centralized lab blinded to the clinical outcomes; patients could test positive for osteoporosis based on either low values of bone strength (vertebral strength ≤ 4,500 N women or 6,500 N men) and/or bone mineral density (vertebral trabecular bone mineral density ≤ 80 mg/cm³ both sexes). Cox proportional hazard ratios were adjusted by age, presence of obesity, and whether the fusion was long (four or more levels fused) or short (3 or fewer levels fused); Kaplan-Meier survival was compared by the log rank test. This project was funded by NIH (R44AR064613) and all physician co-authors and author 1 received salary support from their respective departments. Author 6 is employed by, and author 1 has equity in and consults for, the company that provides the BCT test; the other authors declare no conflicts of interest.

RESULTS

For the 469 patients analyzed (298 women, 171 men), median follow-up time was 44.4 months, 11.1% had a reoperation (median time 14.5 months), and 7.7% had a vertebral fracture (median time 2.0 months). Overall, 25.8% of patients tested positive for osteoporosis and no patients under age 50 tested positive. Compared to patients without osteoporosis, those testing positive were at almost five-fold higher risk for vertebral fracture (adjusted hazard ratio 4.7, 95% confidence interval = 2.2-9.7; p<.0001 Kaplan-Meier survival). Of those positive-testing patients, those who tested positive concurrently for low values of both bone strength and bone mineral density (12.6% of patients overall) were at almost four-fold higher risk for reoperation (3.7, 1.9-7.2; Kaplan-Meier survival p<.0001); the remaining positive-testing patients (those who tested positive for low values of either bone strength or bone mineral density but not both) were not at significantly higher risk for reoperation (1.6, 0.7-3.7) but were for vertebral fracture (4.3, 1.9-10.2). For both clinical outcomes, risk remained high for patients who underwent short or long fusion.

CONCLUSION

In a real-world clinical setting, BCT was effective in identifying primary spinal fusion patients aged 50 or older with osteoporosis who were at elevated risks of reoperation and vertebral fracture.

Disc degeneration contributes to the denser bone in the subendplate but not in the vertebral body in patients with lumbar spinal stenosis or disc herniation

BACKGROUND CONTEXT

It is commonly believed that decreased bone quality would lead to endplate degeneration and arthritic changes in the facet joints, and thus accelerated disc degeneration (DD). However, some more detailed studies of vertebral bone structure have found that bone mineral density (BMD) in the vertebral body is increased rather than decreased in moderate or greater disc degeneration. The relationship between BMD and DD still needs further study. MRI-based vertebral bone quality scores have been shown to be effective in reflecting BMD, rendering a new way to evaluate the changes of vertebral body bone with DD using MRI alone.

PURPOSE

To evaluate MRI-based vertebral bone quality and Pfirrmann grades in patients with lumbar spinal stenosis or disc herniation, and to identify if DD is associated with denser bone around the endplate.

STUDY DESIGN/SETTING

A single-center, retrospective cohort study.

PATIENT SAMPLE

A total of 130 patients with lumbar disc herniation and lumbar spinal stenosis from January 2019 to November 2020 who had a complete dual-energy X-ray absorptiometry scan and noncontrast lumbosacral spine MRI data.

OUTCOME MEASURES

The vertebral bone quality score (VBQ) and sub-endplate bone quality score (EBQ) was calculated as a ratio of the signal intensity of the vertebral bodies and sub-endplate regions to the signal intensity of the cerebrospinal fluid at L3 on the mid-sagittal T1-weighted MRI images, respectively. The Pfirrmann grades of the lumbar discs were assessed as well.

METHODS

The age, gender, body mass index, and T-score of the lumbar spine of the patients were collected. The degeneration grades of the lumbar discs were evaluated according to the Pfirrmann classification. VBQ and EBQ were measured through T1-weighted lumbar MRI. The VBQ and EBQ scores were compared between cranial and caudal sides. The correlation between MRI-based bone quality and DD was calculated. A linear regression model was used to examine the association between DD and adjacent EBQ and VBQ.

RESULTS

This study included 569 lumbar segments from 130 inpatients. Cranial and caudal EBQ decreased with the increase of the Pfirrmann grade. The discs with Pfirrmann grade 5 had significantly lower caudal EBQ than the discs with Pfirrmann grades 2, 3, and 4. In the osteoporosis patients, the Pfirrmann grades negatively correlated both with the cranial EBQ and caudal EBQ. Pfirrmann grade greater than 4 was an independent contributor to the cranial EBQ, whereas greater than 3 was an independent contributor to the caudal EBQ.

CONCLUSIONS

Disc degeneration grades correlated with the EBQ but not with the VBQ. In patients with lumbar spinal stenosis or disc herniation, DD contributes to the denser bone in the sub-endplate, but not in the whole vertebral body.

The predictive value of a novel site-specific MRI-based bone quality assessment, endplate bone quality (EBQ), for severe cage subsidence among patients undergoing standalone lateral lumbar interbody fusion

BACKGROUND CONTEXT

Studies have shown that site-specific bone density measurements had more predictive value for complications than standard whole-region measurements. Recently, MRI-based assessments of vertebral bone quality (VBQ) were introduced. However, there have been few studies that investigate the association between site-specific MRI bone assessment and osteoporosis-related complications in patients undergoing lumbar interbody fusion. In this work, we created a novel site-specific MRI-based assessment of the endplate bone quality (EBQ) and assessed its predictive value for severe cage subsidence following standalone lateral lumbar interbody fusion (SA-LLIF).

PURPOSE

To investigate the predictive value of a novel MRI-based bone assessment for severe cage subsidence after SA-LLIF.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Patients who underwent SA-LLIF from 2008 to 2019 at a single, academic institution with available preoperative lumbar CT and T1-weighted MRIs.

OUTCOME MEASURES

Association between EBQ and severe subsidence after SA-LLIF.

METHODS

We retrospectively reviewed the records of SA-LLIF patients treated between 2008 and 2019. EBQ was measured using preoperative non-contrast T1-weighted MRIs of the lumbar spine. EBQ was defined as the average value of signal intensity of both endplates divided by that of the cerebrospinal fluid space at the level of L3. Bivariate and multivariable analyses with generalized linear mixed models were performed and set binary severe subsidence as the outcome.

RESULTS

Two hundred five levels in 89 patients were included. Fifty levels (24.4%) demonstrated severe subsidence. Bone mineral density measured by quantitative computed tomography was significantly lower in the subsidence group. Both VBQ and EBQ were significantly higher in the subsidence group. The EBQ plus Modic change (MC) model demonstrated that the effect of EBQ was independent of MC. In multivariate analyses adjusted with QCT-vBMD, EBQ showed a significant association with cage subsidence whereas VBQ only showed a marginal trend. The EBQ-based prediction model for severe subsidence showed better goodness of fit compared to the VBQ-based model.

CONCLUSIONS

High EBQ was an independent factor for severe cage subsidence after SA-LLIF and the EBQ-based model showed better goodness of fit compared to VBQ- or MC-based models. EBQ assessment before SA-LLIF may provide insight into a patient's risk for severe subsidence.

Quantitative CT for Preoperative Assessment of Lumbar Degenerative Spondylolisthesis: The Unique Impact of L4 Bone Mineral Density on Single-Level Disease

Background: Quantitative computed tomography (qCT) efficiently measures 3-dimensional vertebral bone mineral density (BMD), but its utility in measuring BMD at various vertebral levels in patients with lumbar degenerative spondylolisthesis (LDS) is unclear. Purpose: We sought to determine whether qCT could differentiate BMD at different levels of LDS, particularly at L4-L5, the most common single level for LDS. In addition, we sought to describe patterns of BMD for single-level and multiple-level LDS. Methods: We conducted a study of patients undergoing surgery for LDS who were part of a larger longitudinal study comparing preoperative and intraoperative images. Preoperative patients were grouped as single-level or multiple-level LDS, and qCT BMD was obtained for L1-S1 vertebrae. Mean BMD was compared with literature reports; in multivariable analyses, BMD of each vertebra was assessed according to the level of LDS, controlling for covariates and for BMD of other vertebrae. Results: Of 250 patients (mean age: 67 years, 64% women), 22 had LDS at L3-L4 only, 170 at L4-L5 only, 13 at L5-S1 only, and 45 at multiple levels. Compared with other disorders reported in the literature, BMD in our sample similarly decreased from L1 to L3 then increased from L4 to S1, but mean BMD per vertebra in our sample was lower. Nearly half of our sample met criteria for osteopenia. In multivariable analysis controlling for BMD at other vertebrae, lower L4 BMD was associated with LDS at L4-L5, greater pelvic incidence minus lumbar lordosis, and not having diabetes. In contrast, in similar multivariable analysis, greater L4 BMD was associated with LDS at L3-L4. Bone mineral density of L3 and L5 was not associated with LDS levels. Conclusion: In our sample of preoperative patients with LDS, we observed lower BMD for LDS than for other lumbar disorders. L4 BMD varied according to the level of LDS after controlling for covariates and BMD of other vertebrae. Given that BMD can be obtained from routine imaging, our findings suggest that qCT data may be useful in the comprehensive assessment of and strategy for LDS surgery. More research is needed to elucidate the cause-effect relationships among spinopelvic alignment, LDS, and BMD.

The clinician's guide to prevention and treatment of osteoporosis

Osteoporosis is the most common metabolic bone disease in the USA and the world. It is a subclinical condition until complicated by fracture(s). These fractures place an enormous medical and personal burden on individuals who suffer from them and take a significant economic toll. Any new fracture in an adult aged 50 years or older signifies imminent elevated risk for subsequent fractures, particularly in the year following the initial fracture. What a patient perceives as an unfortunate accident may be seen as a sentinel event indicative of bone fragility and increased future fracture risk even when the result of considerable trauma. Clinical or subclinical vertebral fractures, the most common type of osteoporotic fractures, are associated with a 5-fold increased risk for additional vertebral fractures and a 2- to 3-fold increased risk for fractures at other sites. Untreated osteoporosis can lead to a vicious cycle of recurrent fracture(s), often resulting in disability and premature death. In appropriate patients, treatment with effective antifracture medication prevents fractures and improves outcomes. Primary care providers and medical specialists are critical gatekeepers who can identify fractures and initiate proven osteoporosis interventions. Osteoporosis detection, diagnosis, and treatment should be routine practice in all adult healthcare settings. The Bone Health and Osteoporosis Foundation (BHOF) - formerly the National Osteoporosis Foundation - first published the Clinician's Guide in 1999 to provide accurate information on osteoporosis prevention and treatment. Since that time, significant improvements have been made in diagnostic technologies and treatments for osteoporosis. Despite these advances, a disturbing gap persists in patient care. At-risk patients are often not screened to establish fracture probability and not educated about fracture prevention. Most concerning, the majority of highest risk women and men who have a fracture(s) are not diagnosed and do not receive effective, FDA-approved therapies. Even those prescribed appropriate therapy are unlikely to take the medication as prescribed. The Clinician's Guide offers concise recommendations regarding prevention, risk assessment, diagnosis, and treatment of osteoporosis in postmenopausal women and men aged 50 years and older. It includes indications for bone densitometry as well as fracture risk thresholds for pharmacologic intervention. Current medications build bone and/or decrease bone breakdown and dramatically reduce incident fractures. All antifracture therapeutics treat but do not cure the disease. Skeletal deterioration resumes sooner or later when a medication is discontinued-sooner for nonbisphosphonates and later for bisphosphonates. Even if normal BMD is achieved, osteoporosis and elevated risk for fracture are still present. The diagnosis of osteoporosis persists even if subsequent DXA T-scores are above - 2.5. Ongoing monitoring and strategic interventions will be necessary if fractures are to be avoided. In addition to pharmacotherapy, adequate intake of calcium and vitamin D, avoidance of smoking and excessive alcohol intake, weight-bearing and resistance-training exercise, and fall prevention are included in the fracture prevention armamentarium. Where possible, recommendations in this guide are based on evidence from RCTs; however, relevant published data and guidance from expert clinical experience provides the basis for recommendations in those areas where RCT evidence is currently deficient or not applicable to the many osteoporosis patients not considered for RCT participation due to age and morbidity.

Low Hounsfield units on computed tomography are associated with cage subsidence following oblique lumbar interbody fusion (OLIF)

BACKGROUND CONTEXT

Cage subsidence is one of the most common complications following lumbar interbody fusion surgery. Low bone mineral density (BMD) is an important risk factor that contributes to cage subsidence. Hounsfield units (HU) obtained from clinical computed tomography (CT) scans provided a reliable method for determining regional BMD. The association between HU and cage subsidence following oblique lumbar interbody fusion (OLIF) remains unclear.

PURPOSE

The objective of this study is to evaluate the association between vertebral HU value and cage subsidence following OLIF.

STUDY DESIGN/SETTING

A retrospective study.

PATIENT SAMPLE

Adults with degenerative spinal conditions underwent single-level OLIF at our institution from October 2017 and August 2020 OUTCOME MEASURES: Cage subsidence, disc height, vertebral body global HU value, upper and lower instrumented vertebrae HU value, endplate HU value, fusion rate.

METHODS

This retrospective study was conducted on patients who underwent single-level OLIF at one institution between October 2017 and August 2020. Cage subsidence was measured using the CT scan postoperatively based on the cage protrusion through the vertebral endplates. The HU values were measured from preoperative CT according to previously reported methods.

RESULTS

A total of 70 patients with a mean follow-up of 15.4 months were included in the analysis. The subsidence rate was 25.7% (n=18/70). The average cage subsidence was 2.2 mm, with a range of 0-7.7 mm. No significant difference was found in age, sex, or body mass index (BMI) between the two groups. The mean global HU value of the lumbar vertebral body (L1-5) was 142.7±30.1 in nonsubsidence and 103.7±11.5 in subsidence (p=.004). The upper instrumented vertebrae (UIV) HU value was 141.4±29.7 in the nonsubsidence and 101.1±10.2 in subsidence, (p=.005). The lower instrumented vertebrae (LIV) HU value was 147.4±34.9 in nonsubsidence and 108.1±13.7 in subsidence, (p<.001). The AUC of the UIV HU value was 0.917 (95% CI: 0.853-0.981), and the most appropriate threshold of the HU value was 115 (sensitivity: 84.6%, specificity: 100%). The AUC of the LIV HU value was 0.893 (95%CI: 0.819-0.966), and the most appropriate threshold of the HU value was 125 (sensitivity: 76.9%, specificity: 100%). The mean upper endplate HU value was 235.4±50.9, and the mean lower endplate HU value was 193.4±40.3. No significant difference (upper endplate p=.314, lower endplate p=.189) was observed between the two groups.

CONSLUSIONS

Lower preoperative vertebral body HU values were associated with cage subsidence after single-level OLIF. However, the endplate HU values were not associated with cage subsidence. Preoperative HU measurement is useful in the prediction of the cage subsidence.

Single-Segment Lumbar Intervertebral Disc Nucleus Excision on the Stability of Lumbar Segmental Sagittal Plane

At present, lumbar disc herniation has become a problem that plagues people's health, life safety, and social and economic development. Among them, the research of lumbar disc nucleus pulposus tissue is the focus of the treatment of lumbar disc diseases. At present, the treatment methods of lumbar disc herniation are divided into conservative treatment and surgical treatment, among which surgical treatment can be divided into open surgery and minimally invasive surgery. Surgical treatment to remove the nucleus pulposus from the disc by fenestration includes conventional ablation of the nucleus pulposus and microscopic lumbar discs. This treatment is effective, but it has a great impact on the stabilization mechanism of the spine, with large soft tissue damage and large blood loss, which can easily cause nerve damage and postdural adhesions. At the same time, single-segment lumbar discectomy has also been gradually applied to the treatment of this disease. Under this, this paper studies single-segment lumbar disc nucleus pulposus resection. The lumbar nucleus resection is performed in a single segment in the physiological load area, which can greatly ensure the stability of the sagittal plane of the lumbar spine. In order to better understand the postoperative rehabilitation and clinical effects of single-segment lumbar discectomy, as well as the changes in the sagittal plane of the lumbar vertebrae before and after the operation, so as to provide a reference for further improving the quality of life of patients, this paper uses questionnaire survey and data analysis methods. According to the results of the questionnaire survey, compared with other operations, single-segment lumbar discectomy is more stable in the sagittal plane of the lumbar spine within the physiological load range, and there is less displacement. The displacement may be caused or influenced by different kinds of factors such as heavy loads or manual labor. In addition, most patients have less abnormal pain after surgery, indicating that the surgery has a certain effect on the treatment of the disease, and there are fewer abnormalities after surgery.

Endplate volumetric bone mineral density is a predictor for cage subsidence following lateral lumbar interbody fusion: a risk factor analysis

BACKGROUND CONTEXT

It has been reported in previous studies that a decreased bone mineral density (BMD) as measured by dual X-ray absorptiometry (DXA) is associated with subsidence. However, there is limited research on the role of volumetric BMD (vBMD) as measured by quantitative computed tomography (QCT). Further, metabolic conditions such as obesity and type 2 diabetes have been associated with poor bone quality, but the impact of these metabolic conditions on on subsidence rates following lateral lumbar interbody fusion (LLIF) remains unclear. As such, risk factors for subsidence following LLIF is an area of ongoing research.

PURPOSE

The purpose of this study is to identify risk factors for subsidence following LLIF with a focus on metabolic conditions and vBMD as measured by QCT.

STUDY DESIGN/SETTING

Retrospective cohort study at a single academic institution.

PATIENT SAMPLE

Consecutive patients undergoing LLIF with or without posterior screws from 2014 to 2019 at a single academic institution who had a pre-operative CT and radiological imaging including radiographs or CT scans between 5 and 14 months post-operatively to assess for cage subsidence.

OUTCOME MEASURE

Subsidence prevalence following LLIF.

METHODS

We reviewed patients undergoing LLIF with or without posterior screws from 2014 to 2019 with a follow-up ≥5 months. Cage subsidence was assessed using the grading system by Marchi et al. Endplate volumetric BMD (EP-vBMD), vertebral bone volumetric BMD (VB-vBMD), BMI, and diabetes status were measured. Univariable analysis and multivariable logistic regression analyses with a generalized mixed model were conducted. Ad hoc analysis, including receiver operative characteristic curve analysis, was used for identifying the cut-off values in significant continuous variables for subsidence. Chi-Squared and ANOVA tests were used for categorical comparisons.

RESULTS

Five hundred sixty-seven levels in 347 patients were included in the final analysis. Mean age (± SD) was 61.7 ± 11.1yrs, 50.3% were male, and 89.6% were Caucasian. Subsidence was observed in 160 levels (28.2%). Multivariable analysis demonstrated an absence of posterior screws [OR = 2.854 (1.483 - 5.215), p=.001] and decreased EP-vBMD [0.996 (0.991 - 1.000), p=.032] were associated with an increased risk of subsidence. Increased BMI and diabetes status were not associated with increased rates of subsidence. Patients without posterior screws and low EP-vBMD experienced subsidence at 44.9% of levels.

CONCLUSIONS

Our results demonstrated that decreased EP-vBMD and standalone status were significantly associated with increased rates of subsidence following LLIF independent of BMI or diabetes status. Further analysis demonstrated that patients with a decreased EP-vBMD and without posterior screws experienced subsidence nearly 2.5 times higher than patients with no risk factors. In patients with a low EP-vBMD undergoing LLIF, posterior screws should be considered.

Osteoporosis and Endplate Damage Correlation Using a Combined Approach of Hounsfield Unit Values and Total Endplate Scores: A Retrospective Cross-Sectional Study

Purpose

Osteoporosis and endplate damage, two primary orthopedic disorders that have adverse effects on the quality of life of older adults, may have some previously unknown relationship. The purpose of this study was to determine the potential association between osteoporosis and endplate damage with two specific imaging scoring systems and analyze the underlying mechanisms.

Patients and Methods

A cross-sectional study including 156 patients with degenerative disc disease (DDD) who visited our department in 2018 was performed. Data including age, sex, body mass index, Hounsfield unit (HU) values utilizing computed tomography (CT), and total endplate scores (TEPSs) using magnetic resonance imaging (MRI) of all patients were retrospectively collected and analyzed. The average HU value and TEPS of L1–L4 were used to represent the degrees of bone mineral density (BMD) and endplate damage, respectively. Patients with an HU value < 110 were defined as having osteoporosis and placed in the low-BMD group; otherwise, they were placed in the normal-BMD group. Multivariate logistic regression models were used to determine the independent factors of endplate damage.

Results

The TEPSs in the low-BMD group were significantly higher (6.4 ± 1.6 vs 5.0 ± 0.9, p < 0.001) overall and in every segment of L1–L4 (p < 0.01). A significant negative correlation was found between TEPS and HU values (p < 0.001). The HU value (odds ratio [OR] 0.221; 95% confidence interval [CI], 0.148–0.295, p < 0.001), age (OR 0.047; 95% CI, 0.029–0.224, p < 0.001), and BMD (OR 3.796; 95% CI, 2.11–7.382, p < 0.05) were independent factors influencing endplate damage.

Conclusion

A significantly positive correlation was observed between osteoporosis and endplate damage, indicating the requirement for a more comprehensive therapeutic regimen for treating patients with DDD complicated with osteoporosis.

The Association Between Endplate Changes and Risk for Early Severe Cage Subsidence Among Standalone Lateral Lumbar Interbody Fusion Patients

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The aim of this study was to investigate the association of Modic type endplate changes with the risk of severe subsidence after standalone lateral lumbar interbody fusion (SA-LLIF).

SUMMARY OF BACKGROUND DATA

It has been reported that certain endplate radiolographic features are associated with higher regional bone mineral density (BMD) in the adjacent vertebrae in the lumbar spine. It remains unclear whether these changes have protective effects against osteoporotic complications such as cage subsidence after lumbar surgery.

METHODS

We reviewed patients undergoing SA-LLIF from 2007 to 2016 with a follow-up >6 months. Cage subsidence was assessed utilizing the grading system by Marchi et al. As potential contributing factors for cage subsidence, we measured the endplate volumetric BMD (EP-vBMD) and the standard trabecular volumetric BMD measurement in the vertebral body. Modic changes (MC) on magnetic resonance imaging were measured as a qualitative factor for endplate condition. Univariate analysis and multivariate logistic regression analyses with a generalized mixed model were conducted.

RESULTS

Two hundred six levels in 97 patients were included in the final analysis. Mean age (± SD) was 66.7 ± 10.7. Sisty-sdpercent of the patients were female. Severe subsidence was observed in 66 levels (32.0%). After adjusting for age, bone morphogenetic protein (BMP) use, and number of levels fused, the presence of MC type 2 was significantly associated with lower risk of severe subsidence (OR = 0.28 [0.09-0.88], P = 0.029). Whereas, EP-vBMD did not demonstrate a statistical significance (p = 0.600).

CONCLUSION

The presence of a Modic type 2 change was significantly associated with lower odds of severe subsidence after SA-LLIF. Nonetheless, this significant association was independent from regional EP-vBMD values. This finding suggests that microstructural and/or material property changes associated with Modic type 2 changes might have a protective effect in this patient population.

LEVEL OF EVIDENCE

4.

The effect of obesity, diabetes, and epidural steroid injection on regional volumetric bone mineral density measured by quantitative computed tomography in the lumbosacral spine

PURPOSE

High body mass index (BMI) is positively correlated with bone mineral density (BMD) in healthy adults; however, the effect of BMI on regional segmental BMDs in the axial skeleton is unclear. In addition, obese patients often have glucose intolerance and patients with lumbar spine pathology commonly have a history of epidural steroid injections (ESIs). The purpose of this study is to evaluate the effect of these patient factors on regional differences in BMD measured by quantitative computed tomography (QCT) in a lumbar fusion patient cohort.

METHODS

The data were obtained from a database comprised of clinical and preoperative CT data from 296 patients who underwent primary posterior lumbar spinal fusion from 2014 to 2017. QCT-vBMDs of L1 to L5, S1 body, and sacral alae were measured. Multivariate linear regression analyses were performed with setting vBMDs as the response variables. As explanatory variables, age, sex, race, current smoking, categorized BMI, diabetes, and ESI were chosen a priori.

RESULTS

A total of 260 patients were included in the final analysis. Multivariate analyses demonstrated that obese and morbidly obese patients had significantly higher vBMD in the sacral alae (SA). Diabetes showed independent positive associations with vBMDs in L1, L2, and the SA. Additionally, patients with an ESI history demonstrated significantly lower vBMD in the SA.

CONCLUSIONS

Our results demonstrate that obesity, diabetes, and epidural steroids affected vBMD differently by lumbosacral spine region. The vBMD of the SA appeared to be more sensitive to various patient factors than other lumbar regions.