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STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The impact of paraspinal sarcopenia following fusions that extend to the upper thoracic spine remain unknown. The purpose of the present study was to assess the impact of sarcopenia on the development of PJK and PJF following spine fusion surgery from the upper thoracic spine to the pelvis. METHODS: We performed a retrospective review of patients who underwent spine fusion surgery that extended caudally to the pelvis and terminated cranially between T1-6. The cohort was divided into 2 groups: (1) patients without PJK or PJF and (2) patients with PJK and/or PJF. Univariate and multivariate analyses were performed to determine risk factors for the development of proximal junctional complications. RESULTS: We identified 81 patients for inclusion in this study. Mean HU at the UIV was 186.1 ± 47.5 in the cohort of patients without PJK or PJF, which was substantially higher than values recorded in the PJK/PJF subgroup (142.4 ± 40.2) (P < 0.001). Severe multifidus sarcopenia was identified at a higher rate in the subgroup of patients who developed proximal junction pathology (66.7%) than in the subgroup of patients who developed neither PJK nor PJF (7.4%; P < 0.001). Multivariate analysis demonstrated both low HU at the UIV and moderate-severe multifidus sarcopenia to be risk factors for the development of PJK and PJF. CONCLUSIONS: Severe paraspinal sarcopenia and diminished bone density at the UIV impart an increased risk of developing PJK and PJF in following thoracolumbar fusions from the upper thoracic spine to the pelvis.
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OBJECTIVE: The purpose of this study was to determine the effect of osteoporosis medications on opportunistic CT-based Hounsfield units (HU). METHODS: Spine and nonspine surgery patients were retrospectively identified who had been treated with romosozumab for 3 to 12 months, teriparatide for 3 to 12 months, teriparatide for > 12 months, denosumab for > 12 months, or alendronate for > 12 months. HU were measured in the L1-4 vertebral bodies. One-way ANOVA was used to compare the mean change in HU among the five treatment regimens. RESULTS: In total, 318 patients (70% women) were included, with a mean age of 69 years and mean BMI of 27 kg/m2. There was a significant difference in mean HU improvement (p < 0.001) following treatment with romosozumab for 3 to 12 months (n = 32), teriparatide for 3 to 12 months (n = 30), teriparatide for > 12 months (n = 44), denosumab for > 12 months (n = 123), and alendronate for > 12 months (n = 100). Treatment with romosozumab for a mean of 10.5 months significantly increased the mean HU by 26%, from a baseline of 85 to 107 (p = 0.012). Patients treated with teriparatide for > 12 months (mean 23 months) experienced a mean HU improvement of 25%, from 106 to 132 (p = 0.039). Compared with the mean baseline HU, there was no significant difference after treatment with teriparatide for 3 to 12 months (110 to 119, p = 0.48), denosumab for > 12 months (105 to 107, p = 0.68), or alendronate for > 12 months (111 to 113, p = 0.80). CONCLUSIONS: Patients treated with romosozumab for a mean of 10.5 months and teriparatide for a mean of 23 months experienced improved spinal bone mineral density as estimated by CT-based opportunistic HU. Given the shorter duration of effective treatment, romosozumab may be the preferred medication for optimization of osteoporotic patients in preparation for elective spine fusion surgery.
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Adult degenerative scoliosis (ADS) is a coronal plane deformity often accompanied by sagittal plane malalignment. Surgical correction may involve the major and/or distally-located fractional curves (FCs). Correction of the FC has been increasingly recognized as key to ameliorating radicular pain localized to the FC levels. The present study aims to summarize the literature on the rationale for FC correction in ADS. Three databases were systematically reviewed to identify all primary studies reporting the rationale for correcting the FC in ADS. Articles were included if they were English full-text studies with primary data from ADS ( ≥ 18 years old) patients. Seventy-four articles were identified, of which 12 were included after full-text review. Findings suggest FC correction with long-segment fusion terminating at L5 increases the risk of distal junctional degeneration as compared to constructs instrumenting the sacrum. Additionally, circumferential fusion offers greater FC correction, lower reoperation risk, and shorter construct length. Minimally invasive surgery (MIS) techniques may offer effective radiographic correction and improve leg pain associated with foraminal stenosis on the FC concavity, though experiences are limited. Open surgery may be necessary to achieve adequate correction of severe, highly rigid deformities. Current data support major curve correction in ASD where the FC concavity and truncal shift are concordant, suggesting that the FC contributes to the patient's overall deformity. Circumferential fusion and the use of kickstand rods can improve correction and enhance the stability and durability of long constructs. Last, MIS techniques show promise for milder deformities but require further investigation.
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STUDY DESIGN: Retrospective observational study of consecutive patients. OBJECTIVE: The purpose of the study was to evaluate VBQ as a predictor of interbody subsidence and to determine threshold values that portend increased risk of subsidence. SUMMARY OF BACKGROUND DATA: Many risk factors have been reported for the subsidence of interbody cages in anterior cervical discectomy and fusion (ACDF). MRI Vertebral Bone Quality (VQB) is a relatively new radiographic parameter that can be easily obtained from preoperative MRI and has been shown to correlate with measurements of bone density such as DXA and CT Hounsfield Units. METHODS: All patients who underwent 1- to 3-level ACDF using titanium interbodies with anterior plating between the years 2018 and 2020 at our tertiary referral center were included. Subsidence measurements were performed by 2 independent reviewers on CT scans obtained 6 months postoperatively. VBQ was measured on pre-operative sagittal T1 MRI by 2 independent reviewers, and values were averaged. RESULTS: Eight-five fusion levels in 44 patients were included in the study. There were 32 levels (38%) with moderate subsidence and 12 levels with severe subsidence (14%). The average VBQ score in those patients with severe subsidence was significantly higher than those without subsidence (3.80 vs. 2.40, P<0.01). A threshold value of 3.2 was determined to be optimal for predicting subsidence (AUC=0.99) and had a sensitivity of 100% and a specificity of 94.1% in predicting subsidence. CONCLUSIONS: VBQ strongly correlates with the subsidence of interbody grafts after ACDF. A threshold VBQ score value of 3.2 has excellent sensitivity and specificity for predicting subsidence. Spine surgeons can use VBQ as a readily available screening tool to identify patients at higher risk for subsidence. LEVEL OF EVIDENCE: Level-IV.
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Vértebras Cervicales , Discectomía , Imagen por Resonancia Magnética , Fusión Vertebral , Humanos , Vértebras Cervicales/cirugía , Vértebras Cervicales/diagnóstico por imagen , Masculino , Femenino , Persona de Mediana Edad , Anciano , Estudios Retrospectivos , Adulto , Densidad ÓseaRESUMEN
Background: Multisegmental pathologic autofusion occurs in patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). It may lead to reduced vertebral bone density due to stress shielding. Methods: This study aimed to determine the effects of autofusion on bone density by measuring Hounsfield units (HU) in the mobile and immobile spinal segments of patients with AS and DISH treated at a tertiary care center. The mean HU was calculated for five distinct regions-cranial adjacent mobile segment, cranial fused segment, mid-construct fused segment, caudal fused segment, and caudal adjacent mobile segment. Means for each region were compared using paired-sample t-tests. Multivariable regression was used to determine independent predictors of mid-fused segment HUs. Results: One hundred patients were included (mean age 76 ± 11 years, 74% male). The mean HU for the mid-construct fused segment (100, 95% CI [86, 113]) was significantly lower than both cranial and caudal fused segments (174 and 108, respectively; both p < 0.001), and cranial and caudal adjacent mobile segments (195 and 115, respectively; both p < 0.001). Multivariable regression showed the mid-construct HUs were predicted by history of smoking (-30 HU, p = 0.009). Conclusions: HUs were significantly reduced in the middle of long-segment autofusion, which was consistent with stress shielding. Such shielding may contribute to the diminution of vertebral bone integrity in AS/DISH patients and potentially increased fracture risk.
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OBJECTIVE: Unplanned returns to the operating room (RORs) constitute an important quality metric in surgical practice. In this study, the authors present a methodology to compare a department's unplanned ROR rates with national benchmarks in the context of large-scale quality of care surveillance. METHODS: The authors identified unplanned RORs within 30 days from the initial surgery at their institution during the period 2014-2018 using an institutional documentation platform that facilitates the collection of reoperation information by providers in the clinical setting. They divided the procedures into 28 groups by Current Procedural Terminology and International Classification of Diseases, 9th and 10th Revision codes. They estimated national benchmarks of unplanned RORs for these procedure groups via querying the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) registry during the period 2014-2018. Finally, they numerically assessed the unplanned ROR rates at their institution compared with those calculated from the ACS NSQIP registry. RESULTS: Using the above methodology, the authors were able to classify 12,575 of the cases performed in their department during the period of interest, including 6037 (48%) cranial cases and 6538 (52%) spinal or peripheral nerve cases. Among those, 161 (1.3%) presented with complications that required an unplanned ROR within 30 days from the initial surgery. The respective cumulative unplanned ROR rate in the ACS NSQIP registry during the same timeframe was 3.6%. Among 15 categories of cranial procedures, the cumulative unplanned ROR rate was 1.3% in the authors' department and 5.6% in the ACS NSQIP registry. Among 13 categories of spinal and peripheral nerve procedures, the cumulative unplanned ROR rate was 1.3% in the authors' department and 2.8% in the ACS NSQIP registry. Unplanned ROR rates at the authors' institution were lower than the national average for each of the 28 procedure groups of interest. Yearly analysis of institutional ROR rates for the five most commonly performed procedures showed lower reoperation rates compared with the national benchmarks. CONCLUSIONS: Using an institutional documentation tool and a widely available national database, the authors developed a reproducible and standardized method of comparing their department's outcomes with national benchmarks per procedure subgroup. This methodology accommodates longitudinal quality surveillance across the different subspecialties in a neurosurgical department and may illuminate potential shortcomings of care delivery in the future.
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OBJECTIVE: To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6). METHODS: Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK. RESULTS: Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106). CONCLUSIONS: In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.
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Cifosis , Vértebras Lumbares , Fusión Vertebral , Vértebras Torácicas , Humanos , Fusión Vertebral/métodos , Masculino , Femenino , Anciano , Vértebras Torácicas/diagnóstico por imagen , Vértebras Torácicas/cirugía , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Persona de Mediana Edad , Cifosis/diagnóstico por imagen , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Imagen por Resonancia Magnética , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/etiología , Densidad Ósea , PronósticoRESUMEN
BACKGROUND AND OBJECTIVES: Cervical disk arthroplasty (CDA) offers the advantage of motion preservation in the treatment of focal cervical pathology. At present, implant sizing is performed using subjective tactile feedback and imaging of trial cages. This study aims to construct interpretable machine learning (IML) models to accurately predict postoperative range of motion (ROM) and identify the optimal implant sizes that maximize ROM in patients undergoing CDA. METHODS: Adult patients who underwent CDA for single-level disease from 2012 to 2020 were identified. Patient demographics, comorbidities, and outcomes were collected, including symptoms, examination findings, subsidence, and reoperation. Affected disk height, healthy rostral disk height, and implant height were collected at sequential time points. Linear regression and IML models, including bagged regression tree, bagged multivariate adaptive regression spline, and k-nearest neighbors, were used to predict ROM change. Model performance was assessed by calculating the root mean square error (RMSE) between predicted and actual changes in ROM in the validation cohort. Variable importance was assessed using RMSE loss. Area under the curve analyses were performed to identify the ideal implant size cutoffs in predicting improved ROM. RESULTS: Forty-seven patients were included. The average RMSE between predicted and actual ROM was 7.6° (range: 5.8-10.1) in the k-nearest neighbors model, 7.8° (range: 6.5-10.0) in the bagged regression tree model, 7.8° (range: 6.2-10.0) in the bagged multivariate adaptive regression spline model, and 15.8° (range: 14.3-17.5°) in a linear regression model. In the highest-performing IML model, graft size was the most important predictor with RMSE loss of 6.2, followed by age (RMSE loss = 5.9) and preoperative caudal disk height (RMSE loss = 5.8). Implant size at 110% of the normal adjacent disk height was the optimal cutoff associated with improved ROM. CONCLUSION: IML models can reliably predict change in ROM after CDA within an average of 7.6 degrees of error. Implants sized comparably with the healthy adjacent disk may maximize ROM.
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Vértebras Cervicales , Aprendizaje Automático , Rango del Movimiento Articular , Humanos , Femenino , Masculino , Persona de Mediana Edad , Vértebras Cervicales/cirugía , Vértebras Cervicales/diagnóstico por imagen , Adulto , Rango del Movimiento Articular/fisiología , Artroplastia/métodos , Prótesis e Implantes , Disco Intervertebral/cirugía , Disco Intervertebral/diagnóstico por imagen , Estudios Retrospectivos , Anciano , Degeneración del Disco Intervertebral/cirugía , Degeneración del Disco Intervertebral/diagnóstico por imagen , Resultado del TratamientoRESUMEN
INTRODUCTION: Interspinous devices (ISDs) and interlaminar devices (ILDs) are marketed as alternatives to conventional surgery for degenerative lumbar conditions; comparisons with decompression alone are limited. The present study reviews the extant literature comparing the cost and effectiveness of ISDs/ILDs with decompression alone. METHODS: Articles comparing decompression alone with ISD/ILD were identified; outcomes of interest included general and disease-specific patient-reported outcomes, perioperative complications, and total treatment costs. Outcomes were analyzed at <6 weeks, 3 months, 6 months, 1 year, 2 years, and last follow-up. Analyses were performed using random effects modeling. RESULTS: Twenty-nine studies were included in the final analysis. ILD/ISD showed greater leg pain improvement at 3 months (mean difference, -1.43; 95% confidence interval, [-1.78, -1.07]; P < 0.001), 6 months (-0.89; [-1.55, -0.24]; P = 0.008), and 12 months (-0.97; [-1.25, -0.68]; P < 0.001), but not 2 years (P = 0.22) or last follow-up (P = 0.09). Back pain improvement was better after ISD/ILD only at 1 year (-0.87; [-1.62, -0.13]; P = 0.02). Short-Form 36 physical component scores or Zurich Claudication Questionnaire (ZCQ) symptom severity scores did not differ between the groups. ZCQ physical function scores improved more after decompression alone at 6 months (0.35; [0.07, 0.63]; P = 0.01) and 12 months (0.23; [0.00, 0.46]; P = 0.05). Oswestry Disability Index and EuroQoL 5 dimensions scores favored ILD/ISD at all time points except 6 months (P = 0.07). Reoperations (odds ratio, 1.75; [1.23, 2.48]; P = 0.002) and total care costs (standardized mean difference, 1.19; [0.62, 1.77]; P < 0.001) were higher in the ILD/ISD group; complications did not differ significantly between the groups (P = 0.41). CONCLUSIONS: Patient-reported outcomes are similar after decompression alone and ILD/ISD; the observed differences do not reach accepted minimum clinically important difference thresholds. ISD/ILDs have higher associated costs and reoperation rates, suggesting current evidence does not support ILD/ISDs as a cost-effective alternative to decompression alone.
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Descompresión Quirúrgica , Degeneración del Disco Intervertebral , Vértebras Lumbares , Humanos , Descompresión Quirúrgica/métodos , Vértebras Lumbares/cirugía , Degeneración del Disco Intervertebral/cirugía , Resultado del TratamientoRESUMEN
BACKGROUND: Long-segment instrumentation, such as Harrington rods, offloads vertebrae within the construct, which may result in significant stress shielding of the fused segments. The present study aimed to determine the effects of spinal fusion on bone density by measuring Hounsfield units (HUs) throughout the spine in patients with a history of Harrington rod fusion. METHODS: Patients with a history of Harrington rod fusion treated at a single academic institution were identified. Mean HUs were calculated at 5 spinal segments for each patient: cranial adjacent mobile segment, cranial fused segment, midconstruct fused segment, caudal fused segment, and caudal adjacent mobile segment. Mean HUs for each level were compared using a paired-sample t test, with statistical significance defined by P < 0.05. Hierarchic multiple regression, including age, gender, body mass index, and time since original fusion, was used to determine predictors of midfused segment HUs. RESULTS: One hundred patients were included (mean age, 55 ± 12 years; 62% female). Mean HUs for the midconstruct fused segment (110; 95% confidence interval [CI], 100-121) were significantly lower than both the cranial and caudal fused segments (150 and 118, respectively; both P < 0.05), as well as both the cranial and caudal adjacent mobile segments (210 and 130, respectively; both P < 0.001). Multivariable regression showed midconstruct HUs were predicted only by patient age (-2.6 HU/year; 95% CI, -3.4 to -1.9; P < 0.001) and time since original surgery (-1.4 HU/year; 95% CI, -2.6 to -0.2; P = 0.02). CONCLUSIONS: HUs were significantly decreased in the middle of previous long-segment fusion constructs, suggesting that multilevel fusion constructs lead to vertebral bone density loss within the construct, potentially from stress shielding.
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Densidad Ósea , Fusión Vertebral , Humanos , Fusión Vertebral/métodos , Fusión Vertebral/instrumentación , Femenino , Persona de Mediana Edad , Masculino , Adulto , Anciano , Estudios Retrospectivos , Vértebras Lumbares/cirugía , Vértebras Lumbares/diagnóstico por imagen , Vértebras Torácicas/cirugía , Vértebras Torácicas/diagnóstico por imagenRESUMEN
Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann-Whitney U tests, Chi-squared analyses, and Fisher's exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.
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OBJECTIVE: Spine metastases are commonly treated with radiotherapy for local tumor control; pathologic fracture is a potential complication of spinal radiotherapy. Both Hounsfield units (HUs) on CT and vertebral bone quality (VBQ) on MRI have been argued to predict stability as measured by odds of pathologic fracture, although it is unclear if there is a difference in the predictive power between the two methodologies. The objective of the present study was to examine whether one methodology is a better predictor of pathologic fracture following radiotherapy for mobile spine metastases. METHODS: Patients who underwent radiotherapy (conventional external-beam radiation therapy, stereotactic body radiation therapy, or intensity-modulated radiation therapy) for mobile spine (C1-L5) metastases at a tertiary care center were retrospectively identified. Details regarding underlying pathology, patient demographics, and tumor morphology were collected. Vertebral involvement was assessed using the Weinstein-Boriani-Biagini (WBB) system. Bone quality of the non-tumor-involved bone was assessed on both pretreatment CT and MRI. Univariable analyses were conducted to identify independent predictors of fracture, and Kaplan-Meier analyses were used to identify significant predictors of time to pathologic fracture. Stepwise Cox regression analysis was used to determine independent predictors of time to fracture. RESULTS: One hundred patients were included (mean age 62.7 ± 11.9 years; 61% male), of whom 35 experienced postradiotherapy pathologic fractures. The most common histologies were lung (22%), prostate (21%), breast (14%), and renal cell (13%). On univariable analysis, the mean HUs of the vertebrae adjacent to the fractured vertebra were significantly lower among those experiencing fracture; VBQ was not significantly associated with fracture odds. Survival analysis showed that average HUs ≤ 132, nonprostate pathology, involvement of ≥ 3 vertebral body segments on the WBB system, Spine Instability Neoplastic Score (SINS) ≥ 7, and the presence of axial pain all predicted increased odds of fracture (all p < 0.001). Cox regression found that HUs ≤ 132 (OR 2.533, 95% CI 1.257-5.103; p = 0.009), ≥ 3 WBB vertebral body segments involved (OR 2.376, 95% CI 1.132-4.987; p = 0.022), and axial pain (OR 2.036, 95% CI 0.916-4.526; p = 0.081) predicted increased fracture odds, while prostate pathology predicted decreased odds (OR 0.076, 95% CI 0.009-0.613; p = 0.016). Sensitivity analysis suggested that an HU threshold of ≤ 132 and a SINS of ≥ 7 identified patients at increased risk of fracture. CONCLUSIONS: The present results suggest that bone density surrogates as measured on CT, but not MRI, can be used to predict the risk of pathologic fracture following radiotherapy for mobile spine metastases. More extensive vertebral body involvement and the presence of mechanical axial pain additionally predict increased fracture odds.
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Fracturas Espontáneas , Fracturas de la Columna Vertebral , Neoplasias de la Columna Vertebral , Humanos , Masculino , Persona de Mediana Edad , Anciano , Femenino , Fracturas Espontáneas/diagnóstico por imagen , Fracturas Espontáneas/etiología , Estudios Retrospectivos , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Neoplasias de la Columna Vertebral/radioterapia , Neoplasias de la Columna Vertebral/complicaciones , Factores de Riesgo , Columna Vertebral/diagnóstico por imagen , Columna Vertebral/patología , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/etiología , DolorRESUMEN
STUDY DESIGN: Retrospective observational study of consecutive patients. OBJECTIVE: The purpose of the study is to determine if a surgeon's qualitative assessment of bone intraoperatively correlates with radiologic parameters of bone strength. SUMMARY OF BACKGROUND DATA: Preoperative radiologic assessment of bone can include modalities such as CT Hounsfield Units (HUs), dual-energy x-ray absorptiometry bone mineral density (DXA BMD) with trabecular bone score (TBS) and MRI vertebral bone quality (VBQ). Quantitative analysis of bone with screw insertional torque and pull-out strength measurement has been performed in cadaveric models and has been correlated to these radiologic parameters. However, these quantitative measurements are not routinely available for use in surgery. Surgeons anecdotally judge bone strength, but the fidelity of the intraoperative judgement has not been investigated. METHODS: All adult patients undergoing instrumented posterior thoracolumbar spine fusion by one of seven surgeons at a single center over a 3-month period were included. Surgeons evaluated the strength of bone based on intraoperative feedback and graded each patient's bone on a 5-point Likert scale. Two independent reviewers measured preoperative CT HUs and MRI VBQ. BMD, lowest T-score and TBS were extracted from DXA within 2 years of surgery. RESULTS: Eighty-nine patients were enrolled and 16, 28, 31, 13 and 1 patients had Likert grade 1 (strongest bone), 2, 3, 4, and 5 (weakest bone), respectively. The surgeon assessment of bone correlated with VBQ (τ=0.15, P=0.07), CT HU (τ=-0.31, P<0.01), lowest DXA T-score (τ=-0.47, P<0.01), and TBS (τ=-0.23, P=0.06). CONCLUSION: Spine surgeons' qualitative intraoperative assessment of bone correlates with preoperative radiologic parameters, particularly in posterior thoracolumbar surgeries. This information is valuable to surgeons as this supports the idea that decisions based on feel in surgery have statistical foundation.
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STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Hounsfield units (HUs) are known to correlate with clinical outcomes, no study has evaluated how they correlate with BCT and DXA measurements. SUMMARY OF BACKGROUND: Low bone mineral density (BMD) represents a major risk factor for fracture and poor outcomes following spine surgery. Dual-energy x-ray absorptiometry (DXA) can provide regional BMD measurements but has limitations. Opportunistic HUs provide targeted BMD estimates; however, they are not formally accepted for diagnosing osteoporosis in current guidelines. More recently, biomechanical computed tomography (BCT) analysis has emerged as a new modality endorsed by the International Society for Clinical Densitometry (ISCD) for assessing bone strength. METHODS: Consecutive cases from 2017-2022 at a single institution were reviewed for patients who underwent BCT in the thoracolumbar spine. BCT-measured vertebral strength, trabecular BMD, and the corresponding American College of Radiology (ACR) Classification were recorded. DXA studies within three months of the BCT were reviewed. Pearson Correlation Coefficients were calculated, and receiver-operating characteristic curves were constructed to assess the predictive capacity of HUs. Threshold analysis was performed to identify optimal HU values for identifying osteoporosis and low BMD. RESULTS: Correlation analysis of 114 cases revealed a strong relationship between HUs and BCT vertebral strength (r=0.69; P<0.0001; R2=0.47) and trabecular BMD (r=0.76; P<0.0001; R2=0.58). However, DXA poorly correlated with opportunistic HUs and BCT measurements. HUs accurately predicted osteoporosis and low BMD (Osteoporosis: C=0.95, 95% CI 0.89-1.00; Low BMD: C=0.87, 95% CI 0.79-0.96). Threshold analysis revealed that 106 and 122 HUs represent optimal thresholds for detecting osteoporosis and low BMD. CONCLUSION: Opportunistic HUs strongly correlated with BCT-based measures, while neither correlated strongly with DXA-based BMD measures in the thoracolumbar spine. HUs are easy to perform at no additional cost and provide accurate BMD estimates at non-instrumented vertebral levels across all ACR-designated BMD categories.
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OBJECTIVE: The purpose of this study was to analyze risk factors for sacral fracture following noninstrumented partial sacral amputation for en bloc chordoma resection. METHODS: A multicenter retrospective chart review identified patients who underwent noninstrumented partial sacral amputation for en bloc chordoma resection with pre- and postoperative imaging. Hounsfield units (HU) were measured in the S1 level. Sacral amputation level nomenclature was based on the highest sacral level with bone removed (e.g., S1 foramen amputation at the S1-2 vestigial disc is an S2 sacral amputation). Variables collected included basic demographics, patient comorbidities, surgical approach, preoperative radiographic details, neoadjuvant and adjuvant radiation therapy, and postoperative sacral fracture data. RESULTS: A total of 101 patients (60 men, 41 women) were included; they had an average age of 69 years, BMI of 29 kg/m2, and follow-up of 60 months. The sacral amputation level was S1 (2%), S2 (37%), S3 (44%), S4 (9%), and S5 (9%). Patients had a posterior-only approach (77%) or a combined anterior-posterior approach (23%), with 10 patients (10%) having partial sacroiliac (SI) joint resection. Twenty-seven patients (27%) suffered a postoperative sacral fracture, all occurring between 1 and 7 months after the index surgery. Multivariable logistic regression analysis demonstrated S1 or S2 sacral amputation level (p = 0.001), combined anterior-posterior approach (p = 0.0064), and low superior S1 HU (p = 0.027) to be independent predictors of sacral fracture. The fracture rate for patients with superior S1 HU < 225, 225-300, and > 300 was 38%, 15%, and 9%, respectively. An optimal superior S1 HU cutoff of 300 was found to maximize sensitivity (89%) and specificity (42%) in predicting postamputation sacral fracture. In addition, the fracture rate for patients who underwent partial SI joint resection was 100%. CONCLUSIONS: Patients with S1 or S2 partial sacral amputations, a combined anterior-posterior surgical approach, low superior S1 HU, and partial SI joint resection are at higher risk for postoperative sacral fracture following en bloc chordoma resection and should be considered for spinopelvic instrumentation at the index procedure.
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Cordoma , Fracturas Óseas , Traumatismos del Cuello , Fracturas de la Columna Vertebral , Neoplasias de la Columna Vertebral , Masculino , Humanos , Femenino , Anciano , Cordoma/diagnóstico por imagen , Cordoma/cirugía , Estudios Retrospectivos , Procedimientos Neuroquirúrgicos/efectos adversos , Factores de Riesgo , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/cirugía , Fracturas de la Columna Vertebral/etiología , Fracturas Óseas/cirugía , Traumatismos del Cuello/cirugía , Sacro/diagnóstico por imagen , Sacro/cirugía , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Neoplasias de la Columna Vertebral/cirugía , Resultado del TratamientoRESUMEN
OBJECTIVE: Proximal junctional kyphosis (PJK) is a complication of surgical management for adult spinal deformity (ASD) with a multifactorial etiology. Many risk factors are controversial, and their relative importance is not fully understood. The authors aimed to elucidate the association between bone mineral density (BMD) and PJK. METHODS: A systematic literature search was performed using PubMed and Web of Science keywords of "Proximal Junctional Kyphosis [MeSH] OR Proximal Junctional Failure [MeSH]" AND "Bone Mineral Density [MeSH] OR Hounsfield Units [MeSH] OR DEXA [MeSH]" set to the date range of January 2002 to July 2022. Studies required a minimum of 10 patients and 12 months of follow-up. Articles were included if they were in the English language and presented a primary retrospective cohort that included a comparison of patients with and without PJK, as well as a radiographic biomarker for BMD, such as Hounsfield units (HU) or T-score. RESULTS: A total of 18 unique studies with 2185 patients who underwent ASD surgery were identified. Of these, 537 patients (24.6%) developed PJK. Eight studies provided T-scores that were amenable to comparison, which found that patients who developed PJK were found to have lower BMD T-scores by a mean of -0.69 (95% CI -0.88 to -0.50; I2 = 63.9%, p < 0.001). The HU at the UIV among patients with the PJK group (n = 101) compared with the non-PJK group (n = 156) was found to be significantly lower (mean difference -32.35, 95% CI -46.05 to -18.65; I2 = 28.7%, p < 0.001). CONCLUSIONS: This meta-analysis suggests that low preoperative BMD as measured by T-score and a diagnosis of osteoporosis were associated with higher postoperative PJK. Additionally, lower HU on CT at the UIV were found to be significant risk factors for postoperative PJK as well. These findings suggest that more attention to preoperative BMD is a risk factor for PJK among ASD patients is warranted.
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Cifosis , Fusión Vertebral , Humanos , Adulto , Estudios Retrospectivos , Densidad Ósea , Vértebras Torácicas/cirugía , Fusión Vertebral/efectos adversos , Complicaciones Posoperatorias/cirugía , Cifosis/diagnóstico por imagen , Cifosis/cirugía , Cifosis/complicaciones , Factores de RiesgoRESUMEN
STUDY DESIGN: Retrospective review. OBJECTIVE: The purpose of this study was to investigate the surgical outcomes in a cohort of patients with severe preoperative axial neck pain undergoing laminoplasty for cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: No study has investigated whether patients with severe axial symptoms may achieve satisfactory neck pain and disability outcomes after laminoplasty. METHODS: We performed a retrospective review of 91 patients undergoing C4-6 laminoplasty for CSM at a single academic institution between 2010 and 2021. Patient-reported outcome measures (PROMs), including Neck Disability Index (NDI), visual analog scale (VAS) Neck, and VAS Arm, were recorded preoperatively and at 6 months and 1 year postoperatively. Patients were stratified as having mild pain if VAS neck was 0-3, moderate pain if 4-6, and severe pain if 7-10. PROMs were then compared between subgroups at all the perioperative time points. RESULTS: Both the moderate and severe neck pain subgroups demonstrated a substantial improvement in VAS neck from preoperative to 6 months postoperatively (-3.1±2.2 vs. -5.6±2.8, respectively; P <0.001), and these improvements were maintained at 1 year postoperatively. There was no difference in VAS neck between subgroups at either the 6-month or 1-year postoperative time points. Despite the substantially higher mean NDI in the moderate and severe neck pain subgroups preoperatively, there was no difference in NDI at 6 months or 1 year postoperatively ( P =0.99). There were no differences between subgroups in the degree of cord compression, severity of multifidus sarcopenia, sagittal alignment, or complications. CONCLUSIONS: Patients with moderate and severe preoperative neck pain undergoing laminoplasty achieved equivalent PROMs at 6 months and 1 year as patients with mild preoperative neck pain. The results of this study highlight the multifactorial nature of neck pain in these patients and indicate that severe axial symptoms are not an absolute contraindication to performing laminoplasty in well-aligned patients with CSM.
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Laminoplastia , Dolor de Cuello , Enfermedades de la Médula Espinal , Espondilosis , Humanos , Vértebras Cervicales/cirugía , Contraindicaciones , Laminoplastia/métodos , Dolor de Cuello/cirugía , Dolor de Cuello/complicaciones , Estudios Retrospectivos , Enfermedades de la Médula Espinal/complicaciones , Enfermedades de la Médula Espinal/cirugía , Espondilosis/complicaciones , Espondilosis/cirugía , Resultado del TratamientoRESUMEN
BACKGROUND: The management of adult spinal deformity (ASD) relies upon retrospective data, but there have been calls for prospective trials to improve the evidentiary base. This study sought to define the state of the spinal deformity clinical trials and highlight trends to guide future research. METHODS: The ClinicalTrials.gov database was queried for all ASD trials initiated since 2008. ASD was defined as adults (>18 years) and defined by the trial. All identified trials were categorized by enrollment status, study design, funding source, start and completion dates, country, outcomes examined, among many other study characteristics. RESULTS: Sixty trials were included, of which 33(55.0%) started within the past 5 years of the query date. Most trials were sponsored by academic centers (60.0%) followed by industry (48.3%). Notably, 16 (27%) trials had multiple funding sources, all included collaboration with an industry entity. Only one trial had funding from a government agency. There were 30 (50%) interventional and 30 (50%) observational studies. The average time to completion was 50.8 ± 49.1 months. A total of 23 (38.3%) studies investigated a new procedural innovation, while 17 (28.3%) studies examined the safety or efficacy of a device. Study publications were associated with 17 (28.3%) trials in the registry. CONCLUSIONS: The number of trials has increased significantly over the past 5 years, with the bulk of trials being funded by academic centers and industry and a notably lack by government agencies. Most trials focused on device or procedural investigation. Despite growing interest in ASD clinical trials, there remain many points for improvement in the current evidentiary base.
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Industrias , Proyectos de Investigación , Humanos , Estudios Prospectivos , Estudios Retrospectivos , Sistema de RegistrosRESUMEN
STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The present study is the first to assess the impact of paraspinal sarcopenia on patient-reported outcome measures (PROMs) following cervical laminoplasty. BACKGROUND: While the impact of sarcopenia on PROMs following lumbar spine surgery is well-established, the impact of sarcopenia on PROMs following laminoplasty has not been investigated. METHODS: We performed a retrospective review of patients undergoing laminoplasty from C4-6 at a single institution between 2010 and 2021. Two independent reviewers utilized axial cuts of T2-weighted magnetic resonance imaging sequences to assess fatty infiltration of the bilateral transversospinales muscle group at the C5-6 level and classify patients according to the Fuchs Modification of the Goutalier grading system. PROMs were then compared between subgroups. RESULTS: We identified 114 patients for inclusion in this study, including 35 patients with mild sarcopenia, 49 patients with moderate sarcopenia, and 30 patients with severe sarcopenia. There were no differences in preoperative PROMs between subgroups. Mean postoperative neck disability index scores were lower in the mild and moderate sarcopenia subgroups (6.2 and 9.1, respectively) than in the severe sarcopenia subgroup (12.9, P =0.01). Patients with mild sarcopenia were nearly twice as likely to achieve minimal clinically important difference (88.6 vs. 53.5%; P <0.001) and six times as likely to achieve SCB (82.9 vs. 13.3%; P =0.006) compared with patients with severe sarcopenia. A higher percentage of patients with severe sarcopenia reported postoperative worsening of their neck disability index (13 patients, 43.3%; P =0.002) and Visual Analog Scale Arm scores (10 patients, 33.3%; P =0.03). CONCLUSION: Patients with severe paraspinal sarcopenia demonstrate less improvement in neck disability and pain postoperatively and are more likely to report worsening PROMs following laminoplasty. LEVEL OF EVIDENCE: 3.
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Vértebras Cervicales , Laminoplastia , Dolor de Cuello , Sarcopenia , Humanos , Estudios Retrospectivos , Sarcopenia/complicaciones , Medición de Resultados Informados por el Paciente , Laminoplastia/métodos , Resultado del Tratamiento , Dolor de Cuello/etiología , Vértebras Cervicales/diagnóstico por imagen , Vértebras Cervicales/cirugía , Masculino , Femenino , Adulto , Persona de Mediana Edad , AncianoRESUMEN
AIM: To measure the baseline spinopelvic parameters and characterize the sagittal, and coronal plane deformities in patients with idiopathic normal pressure hydrocephalus (iNPH). MATERIAL AND METHODS: We analyzed a series of patients at one academic institution who underwent ventriculoperitoneal shunting for iNPH with pre-shunt standing full length x-rays. The series of patients was enrolled consecutively to minimize selection bias. We quantified comorbid sagittal plane spinal deformity based on the Scoliosis Research Society-Schwab classification system by assessing pelvic incidence and lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), and sagittal vertical axis (SVA). RESULTS: Seventeen patients (59% male) were included in this study. Mean (± standard deviation) age was 74 ± 5.3 years with a body mass index (BMI) of 30 ± 4.5 kg/m < sup > 2< sup > . Six patients (35%) had marked sagittal plane spinal deformity by at least one parameter: five (29%) had greater than 20Ë PI-LL mismatch, three (18%) had > 9.5 cm SVA, and one (6%) had PT greater than 30Ë. Additionally, the thoracic kyphosis exceeded the lumbar lordosis in nine patients (53%). CONCLUSION: Positive sagittal balance, with thoracic kyphosis exceeding lumbar lordosis, is common in iNPH patients. This may lead to postural instability, especially in patients whose gait does not improve following shunting. These patients may warrant further investigation and workup, including full length standing x-rays. Future studies should assess for improvement in the sagittal plane parameters following shunt placement.