Radiographic analysis of the sacral-2-alar screw trajectory

Purpose To explore the feasibility of sacral-2-alar (S2-alar) screw placement by measuring the length, diameter, and angle of the screw trajectory on computed tomography (CT). Methods This study selected 100 Han-nationality adults in northern China with a normal spine and pelvis. CT data were imported into PHILIPS software for reconstructing the 3D digital images. The optimal S2-alar screw trajectory was imitated on CT. Parameters including the length of the screw trajectory, sagittal angle, coronal angle, distance between the entry point and the spinous process, and minimum diameter of the screw trajectory were measured to evaluate the application of S2-alar screws. Results In total, 48 males and 52 females were included. The average length of the left screw trajectory was 47.18 ± 3.91 mm. The sagittal angle was 29.06 ± 4.00°. The coronal angle was 13.31 ± 6.95°. The distance between the entry point and the spinous process was 21.0 (3.7) mm. The minimum diameter of the screw trajectory was 17.1 (2.3) mm. The average length of the right screw trajectory was 45.46 ± 4.37 mm. The sagittal angle was 23.33 ± 4.26°. The coronal angle was 14.88 ± 6.84°. The distance between the entry point and the spinous process was 22.8 (2.9) mm. The minimum diameter of the screw trajectory was 16.9 (3.1) mm. In women, the average length of the left screw trajectory was 44.80 ± 3.66 mm. The sagittal angle was 32.14 ± 5.48°. The coronal angle was 16.04 ± 7.74°. The distance between the entry point and the spinous process was 21.8 (2.8) mm. The minimum diameter of the screw trajectory was 17.1 (5) mm. The average length of the right screw trajectory was 44.01 ± 3.72 mm. The sagittal angle was 25.12 ± 5.19. The coronal angle was 16.67 ± 8.34°. The distance between the entry point and the spinous process was 21.6 (2.7) mm. The minimum diameter of the screw trajectory was 17 (4.5) mm. As seen from the data, there were significant differences in the minimum diameter of the screw trajectory in both males and females. In females, there were also significant differences between the left and right sides in the coronal angle. Between males and females, there were statistically significant differences in the length of the screw trajectory. There were no statistically significant differences in the other parameters between males and females. Conclusion The optimal screw trajectory of the S2-alar screw can be found on CT. The length and deflection angle of the screw meet the clinical requirements. This method is easy to perform and feasible for clinical application.

Patterns of spinal cord malformation in cloacal exstrophy

OBJECTIVE The objective of this study was to assess the prevalence and spectrum of spinal dysraphism in a cohort of children with cloacal exstrophy (CEX) using MRI. METHODS Children with CEX presenting between 1999 and 2019 with baseline spinal MRI were included. The images were reviewed in consensus to assess the type of dysraphism. The dysraphisms were initially reviewed and described based on their descriptive anatomy, and then classified according to anomalies of gastrulation, primary neurulation, or secondary neurulation. RESULTS Thirty-four children were included. Thirty-three of these children had closed spinal dysraphism, and 1 had a normal spine. Of the 33 cases of closed spinal dysraphism, the conus and/or filum terminale were involved in all cases. The most common malformations were spinal lipoma (n = 20) and terminal myelocystocele (n = 11). The lipomas were heterogeneous: 4 dorsal, 9 transitional, 4 chaotic, and 3 terminal. A large subgroup (10/20, 50%) within the lipomas had an unusual morphology of noncontiguous double lipomas, the proximal fat related to the conus and the distal fat within the filum. These were difficult to characterize using existing classifications. In 2 cases, only a thickened filum was noted. The majority of these malformations were compatible with a disorder of secondary neurulation. CONCLUSIONS Complex spinal dysraphisms are consistently associated with CEX. The unusual dysraphism patterns found in this group of patients highlight the limitations of current embryological classifications. Given the propensity for neurological deterioration in this group of patients, spinal MRI should be routinely performed. The type and distribution of malformations seen have implications for the wider understanding of the pathogenesis and classification of lumbosacral lipomas.

An unusual case of childhood osteoarticular tuberculosis from the Árpádian Age cemetery of Győrszentiván-Révhegyi tag (Győr-Moson-Sopron county, Hungary)

Ancient human remains exhibiting bony changes consistent with osteoarticular tuberculosis (OATB) indicate that the disease has afflicted mankind for millennia. Nonetheless, not many pediatric OATB cases have been published in the paleopathological literature–from Hungary, only three cases have been described up to now. In our paper, we demonstrate a child (S0603) from the Árpádian Age cemetery of Győrszentiván-Révhegyi tag (northwestern Hungary), who represents a unique case of OATB regarding both the pattern and severity of the observed bony changes. During the macromorphological and radiological investigations, the most serious alterations were discovered in the upper thoracic spine–the development of osteolytic lesions led to severe bone loss and consequent collapse and fusion of several adjacent vertebrae. The pathological process terminated in a sharp, rigid angular kyphosis. Disruption of the normal spine curvature resulted in consequent deformation of the whole thoracic wall–it became “rugby-ball-shaped”. The overall nature and pattern of the detected alterations, as well as their resemblance to those of described in previously published archaeological and modern cases from the pre-antibiotic era indicate that they are most consistent with OATB. Based on the severity and extent of the lesions, as well as on the evidence of secondary healing, S0603 suffered from TB for a long time prior to death. Besides body deformation, OATB resulted in consequent disability in daily activities, which would have required regular and significant care from others to survive. It implies that in the Árpádian Age community of Győrszentiván-Révhegyi tag, there was a willingness to care for people in need. Detailed archaeological case studies can give us a unique insight into the natural history and different presentations of OATB. Furthermore, they can provide paleopathologists with a stronger basis for diagnosing TB and consequently, with a more sensitive means of assessing TB frequency in past populations.

SIPA1L1/SPAR1 is a non-PSD protein involved in GPCR signaling

SIPA1L1 (also known as SPAR1) has been proposed to regulate synaptic functions that are important in maintaining normal neuronal activities, such as regulating spine growth and synaptic scaling, as a component of the postsynaptic density (PSD)-95/N-methyl-D-aspartate receptor (NMDA-R)-complex. However, contrary to this view, our super-resolution and immunoelectron microscopic analyses demonstrate that SIPA1L1 is mainly localized to general submembranous and cytoplasmic regions in neurons, but scarcely to PSD. Our screening for native interactors of SIPA1L1 identified spinophilin and neurabin-1, regulators of G protein-coupled receptor (GPCR) signaling, but rejected PSD-95/NMDA-R-complex components. Furthermore, Sipa1l1-/- mice showed normal spine size distribution and NMDA-R-dependent synaptic plasticity. Nevertheless, Sipa1l1-/- mice showed aberrant responses to α2-adrenergic receptor (a spinophilin target) or adenosine A1 receptor (a neurabin-1 target) agonist stimulation and striking behavioral anomalies, such as hyperactivity, enhanced anxiety, learning impairments, social interaction deficits, and enhanced epileptic seizure susceptibility. Our findings revealed unexpected properties of SIPA1L1, suggesting a possible association of SIPA1L1 deficiency with neuropsychiatric disorders related to dysregulated GPCR signaling, such as epilepsy, attention deficit hyperactivity disorder (ADHD), autism, or fragile X syndrome.

The influence of the rib cage on the static and dynamic stability responses of the scoliotic spine

The thoracic cage plays an important role in maintaining the stability of the thoracolumbar spine. In this study, the influence of a rib cage on static and dynamic responses in normal and scoliotic spines was investigated. Four spinal finite element (FE) models (T1–S), representing a normal spine with rib cage (N1), normal spine without rib cage (N2), a scoliotic spine with rib cage (S1) and a scoliotic spine without rib cage (S2), were established based on computed tomography (CT) images, and static, modal, and steady-state analyses were conducted. In S2, the Von Mises stress (VMS) was clearly decreased compared to S1 for four bending loadings. N2 and N1 showed a similar VMS to each other, and there was a significant increase in axial compression in N2 and S2 compared to N1 and S1, respectively. The U magnitude values of N2 and S2 were higher than in N1 and S1 for five loadings, respectively. The resonant frequencies of N2 and S2 were lower than those in N1 and S1, respectively. In steady-state analysis, maximum amplitudes of vibration for N2 and S2 were significantly larger than N1 and S1, respectively. This study has revealed that the rib cage improves spinal stability in vibrating environments and contributes to stability in scoliotic spines under static and dynamic loadings.

Optimization of a Bayesian penalized likelihood algorithm (Q.Clear) for 18F-NaF bone PET/CT images acquired over shorter durations using a custom-designed phantom

Background The Bayesian penalized likelihood (BPL) algorithm Q.Clear (GE Healthcare) allows fully convergent iterative reconstruction that results in better image quality and quantitative accuracy, while limiting image noise. The present study aimed to optimize BPL reconstruction parameters for 18F-NaF PET/CT images and to determine the feasibility of 18F-NaF PET/CT image acquisition over shorter durations in clinical practice. Methods A custom-designed thoracic spine phantom consisting of several inserts, soft tissue, normal spine, and metastatic bone tumor, was scanned using a Discovery MI PET/CT scanner (GE Healthcare). The phantom allows optional adjustment of activity distribution, tumor size, and attenuation. We reconstructed PET images using OSEM + PSF + TOF (2 iterations, 17 subsets, and a 4-mm Gaussian filter), BPL + TOF (β = 200 to 700), and scan durations of 30–120 s. Signal-to-noise ratios (SNR), contrast, and coefficients of variance (CV) as image quality indicators were calculated, whereas the quantitative measures were recovery coefficients (RC) and RC linearity over a range of activity. We retrospectively analyzed images from five persons without bone metastases (male, n = 1; female, n = 4), then standardized uptake values (SUV), CV, and SNR at the 4th, 5th, and 6th thoracic vertebra were calculated in BPL + TOF (β = 400) images. Results The optimal reconstruction parameter of the BPL was β = 400 when images were acquired at 120 s/bed. At 90 s/bed, the BPL with a β value of 400 yielded 24% and 18% higher SNR and contrast, respectively, than OSEM (2 iterations; 120 s acquisitions). The BPL was superior to OSEM in terms of RC and the RC linearity over a range of activity, regardless of scan duration. The SUVmax were lower in BPL, than in OSEM. The CV and vertebral SNR in BPL were superior to those in OSEM. Conclusions The optimal reconstruction parameters of 18F-NaF PET/CT images acquired over different durations were determined. The BPL can reduce PET acquisition to 90 s/bed in 18F-NaF PET/CT imaging. Our results suggest that BPL (β = 400) on SiPM-based TOF PET/CT scanner maintained high image quality and quantitative accuracy even for shorter acquisition durations.

CAP2 is a novel regulator of Cofilin in synaptic plasticity and Alzheimer’s disease

Cofilin is one of the major regulators of actin dynamics in spines where it is required for structural synaptic plasticity. However, our knowledge of the mechanisms controlling Cofilin activity in spines remains still fragmented. Here, we describe the cyclase-associated protein 2 (CAP2) as a novel master regulator of Cofilin localization in spines. The formation of CAP2 dimers through its Cys32 is important for CAP2 binding to Cofilin and for normal spine actin turnover. The Cys32-dependent CAP2 homodimerization and association to Cofilin are triggered by long-term potentiation (LTP) and are required for LTP-induced Cofilin translocation into spines, spine remodeling and the potentiation of synaptic transmission. This mechanism is specifically affected in the hippocampus, but not in the superior frontal gyrus, of both Alzheimer’s Disease (AD) patients and APP/PS1 mice, where CAP2 is down-regulated and CAP2 dimer synaptic levels are reduced. In AD hippocampi, Cofilin preferentially associates with CAP2 monomer and is aberrantly localized in spines. Taken together, these results provide novel insights into structural plasticity mechanisms that are defective in AD.

Scoliosis and spinal deformity

Spinal deformity is very common in the ageing population and also fairly common in the paediatric population. An understanding of the normal spinal profile in growth and ageing is essential for the successful treatment of all spinal pathology. This chapter describes the normal spine and the clinical and radiographic assessment of spinal shape. We also discuss the classification and treatment of scoliosis and kyphosis in children and adults. Spinal deformity surgery is a major undertaking and carries significant risks. These risks can be managed and reduced with a systematic approach to the care of these patients which this chapter explores.

Evaluation of the applicability of musculoskeletal ultrasonography of the thoracolumbar and lumbar spine segment of healthy dogs

ABSTRACT: Changes in the spine of dogs are usually detected in clinical and in surgical practice. Few studies exist on musculoskeletal ultrasound anatomy of the thoracolumbar and lumbar segments of the normal spine of dogs. This study aimed to compare the normal musculoskeletal ultrasound anatomy of the T10-S1 vertebral segments with images obtained with magnetic resonance imaging (MRI), computed tomography (CT), and anatomical structures, and to establish the ability to identify structures using these modalities. Ultrasound scans allowed visualization of the muscles of the region, articular processes, spinous process, interspinous ligament, and yellow ligament in the lumbosacral window. Computed tomography images provided better bone details, compared to ultrasound images. Low-field MRI allowed the identification of the same structures identified with ultrasound imaging, and allowed the identification of cerebrospinal fluid, transverse processes, and provided improved detail of the intervertebral discs and spinal cord. Knowledge of ultrasound anatomy of the region may allow the the identification of muscle and ligament injuries. Thus, in cities where CT and MRI are inaccessible, ultrasonography of the region could be a good alternative to identify possible changes not observable with radiographic examination or to complement radiographic examination.