What is the role of CT-based Hounsfield unit assessment in the evaluation of bone mineral density in patients undergoing 1- or 2-level lumbar spinal fusion for degenerative spinal pathologies? A prospective study.

BACKGROUND CONTEXT: Computed tomography-based vertebral attenuation values (CT-based HU) have been shown to correlate with T-scores on DEXA scan; and have been acknowledged as an independent factor for predicting fragility fractures. Most patients undergoing lumbar surgeries require CT as part of their preoperative evaluation. PURPOSE: The current study was thus planned to evaluate the role of lumbar CT as an opportunistic investigation in determining BMD preoperatively in patients undergoing lumbar fusion. STUDY DESIGN: Prospective cohort study. PATIENT SAMPLE: Patients older than 45 years, who underwent one- to two-level lumbar (L3-S1 levels) fusions. OUTCOME MEASURES: Comparison of the quantitative assessment of osteoporosis using Hounsfield Units (HU) on CT (L1-L5) and mean lumbar T-scores on DEXA (Dual Energy X-ray Absorptiometry). HYPOTHESIS: HU on CT is comparable to T-score on DEXA as a suitable modality for the assessment of osteoporosis in patients undergoing one- to two-level lumbar fusion. METHODS: A prospective cohort study was conducted between January and December 2021. Patients older than 45 years, who underwent one- to two-level lumbar (L3-S1 levels) fusions and had complete clinico-radiological records, were prospectively enrolled. A comparison was drawn between the HU (measured by placing an oval region of interest [ROI] over axial, sagittal and coronal images of lumbar vertebrae) on CT and T-scores on DEXA, and analyzed statistically. The HU values correlating best with normal (group A), osteopenia (B) and osteoporosis (C) categories (classified based on T-scores of lumbar spines) were determined statistically. RESULTS: Overall, 87 patients (mean age of 60.56±11.63 years; 63 [72.4%] female patients) were prospectively studied. There was a statistically significant difference in the mean age (p=.01) and sex distribution (predominantly female patients; p=.03) of patients belonging to groups B (osteopenic) and C (osteoporotic patients), as compared with group A. The greatest correlation between T-score (on DEXA) and HU (on CT) for differentiating osteopenia (group B) from group A was observed at levels L1 (p<.001), L2 (p<.001) and L3 (p<.001). Based on receiver-operating characteristic (ROC) curve analysis, the cut-off values for HU for identifying osteopenia were 159 (at L1; sensitivity 81.6 and specificity 80) and 162 (at L2; sensitivity 80 and specificity 71.1). In addition, there was statistically significant correlation between T-score (on DEXA) and HU at all the lumbar levels for distinguishing osteoporosis (group C), although the difference was most evident at the upper lumbar (L1 and L2) levels (p<.001). Based on ROC analysis, cut-off HU values for defining osteoporosis were 127 (at L1; sensitivity 71.3 and specificity 70) and 117 (at L2; sensitivity 65.5 and specificity 90). CONCLUSION: Based on our study, the measurement of HU on CT at upper lumbar levels can be considered as "surrogate marker" for BMD in the diagnosis of osteopenia (cut-off: 159 at L1, 162 at L2) and osteoporosis (cut-off: 127 at L1, 117 at L2) in patients undergoing lumbar fusion surgeries. The HU measurements on CT at the lower lumbar levels (L4 and L5) are less reliable in this preoperative scenario.

Type I Arnold Chiari Malformation with Syringomyelia and Scoliosis: Radiological Correlations between Tonsillar Descent, Syrinx Morphology and Curve Characteristics: A Retrospective Study.

STUDY DESIGN: Retrospective cohort. PURPOSE: The current study was planned to evaluate deformity characteristics, assess relationship between morphology of syrinx/Arnold Chiari malformation (ACM) and deformity, analyze effect of posterior fossa decompression (PFD), and evaluate outcome. OVERVIEW OF LITERATURE: Scoliosis in ACM-I and syringomyelia (SM) is uncommon, and deformity characteristics differ from those seen in idiopathic scoliosis. METHODS: Data regarding patients, who underwent PFD for ACM-I presenting with SM and scoliosis between January 2009 and December 2018, were retrospectively collected. Only patients with 2-year follow-up were included. Sagittal/coronal deformity and sagittal spinopelvic parameters were examined. Symmetry and extent of tonsillar descent, as well as morphology (configuration/variation) and extent of syrinx were determined. RESULTS: A total of 42 patients (20 females; age: 14.2±5.8 years) were included; 35 patients (83.3%) had atypical curves. Mean preoperative coronal Cobb was 57.7°±20.9°; and 12 (28.6%) had significant coronal imbalance. Tonsillar descent was classified as grade 1, 2, and 3 in 16 (38.1%), 11 (26.2%), and 15 (35.7%) patients; 35 patients (83.3%) had asymmetric tonsillar descent; 17 (40.4%), 3 (7.1%), 16 (38.1%), and 6 (14.4%) had circumscribed, moniliform, dilated, and slender syrinx patterns; and 9 (21.4%), 12 (28.6%), and 21 (50%) of syrinx were right-sided, left-sided, and centric. There was no significant relationship between side of tonsillar dominance (p =0.31), grade of descent (p =0.30), and convexity of deformity. There was significant association between side of syrinx and convexity of scoliosis (p =0.01). PFD was performed in all, and deformity correction was performed in 23 patients. In curves ≤40°, PFD alone could stabilize scoliosis progression (p =0.02). There was significant reduction in syrinx/cord ratio following PFD (p <0.001). CONCLUSIONS: ACM-I+SM patients had atypical curve patterns in 83% of cases, and the side of syrinx deviation correlates with scoliosis convexity. Syrinx shrinks significantly following PFD. PFD may not stabilize scoliosis in curves >40°.

A rare case of hydatid cyst of the neck with concurrent pulmonary hydatid disease.

Echinococcosis, commonly known as hydatid disease, is a zoonotic infection caused by dog tapeworm Echinococcus granulosus. Hydatid disease of the head and neck region is scarcely reported even in endemic areas. We herein report a case with with neck swelling and respiratory symptoms subsequently diagnosed to have disseminated echinococcosis of the neck and left lung.

A Mechanistic Based Analysis of Clinicoradiological and Functional Outcome in C7-T1 Translational Injury.

OBJECTIVES: C7-T1 translational injuries are relatively rare, unstable, and usually associated with neurological impairment. We aim to analyze the C7-T1 translational injury based on Allen and Ferguson's classification and to highlight the clinicoradiologic and neurologic outcomes in these patients. METHODS: Patients with C7-T1 translational injury were retrospectively analyzed and demographic data, mechanism, mode of injury, surgery details, and associated injuries were obtained. The initial neurologic status was recorded as American Spinal Injury Association (ASIA) grade. All the injuries were classified as per Allen and Ferguson classification and stage 4 compressive extension (CE) injury was further classified into stage 4a and stage 4b according to Rebich et al. RESULTS: Among 44 patients, the most common mechanism of injury was CE injury seen in 27 patients (61.4%) followed by distractive flexion (DF) in 16 patients (36.4%) and compressive flexion in 1 patient (2.2%). Neurologic deficit was noted in 14 of 27 patients (51.85%) with CE injury, which was less compared to 12 of 16 patients (75%) with DF injury. However, there was no significant difference in terms of neurologic recovery. One patient with standalone anterior fixation had implant loosening and underwent additional posterior fixation. CONCLUSIONS: We present the largest series of C7-T1 translational injuries in the literature to our best knowledge. CE injury is nearly 2 times more common than DF injury and is associated with a lower incidence of neurologic deficit and easier fracture reduction techniques. Staging the injury severity aids in better planning in terms of surgical approach and levels of fixation.