BackgroundSimple range of motion measurements in individuals with non-specific chronic low back pain (NSCLBP) during forward bending provide limited information about the directional characteristics of spinal movements.PurposeTo examine the horizontal and vertical displacement trajectories of thoracolumbar regions (T12 and L2 levels) during forward bending using smartphone-based 2-dimensional video analysis, and to compare kinematics among NSCLBP subgroups classified as the flexion pattern (FP) and extension pattern (EP), and healthy controls.MethodsA total of 185 participants were recruited (58 healthy, 87 FP, 40 EP). Two markers were positioned over the spinous processes of T12 and L2. Marker trajectories were tracked using Kinovea software, and displacements along the x- (anterior-posterior) and y-axes (superior-inferior) were measured.ResultsThe EP group showed significantly greater anterior displacement at the T12 and L2 levels than the FP group, and at the L2 level than healthy controls. No significant differences were found between FP and healthy groups or in vertical displacement of the two markers.ConclusionsHorizontal displacement trajectories effectively differentiated NSCLBP subgroups, particularly identifying a distinct movement strategy in the EP group. Smartphone-based video analysis may offer a clinically useful and accessible tool for subgroup-specific assessment.

While distinguishing between collis and caput patterns in cervical dystonia (CD) has clear clinical and therapeutic relevance, the effects of botulinum toxin type A (BoNT-A) on segmental spinal excitability and inhibitory function in caput-pattern CD have not been previously investigated. This study aimed to advance understanding of the effects of BoNT-A and its broader neurophysiological impact in cervical dystonia, particularly in the caput subtype. The study utilised non-invasive neurophysiological methods to assess F-wave and cutaneous silent period (CSP or CuSP) parameters in 21 CD patients with caput motor patterns at waning and peak response phases of BoNT-A therapy. Significant prolongation of Fmin latency, increased F–M interlatency, reduced F-wave amplitude, and a marked increase in CSP duration and onset latencies were observed following BoNT-A administration, indicating that BoNT-A not only reduces spinal motoneuron excitability and strengthens spinal inhibitory processes, but also highlights its capacity to modulate central sensorimotor pathways beyond local chemodenervation. Together, the observed changes in CSP support its use as a potential biomarker for nervous system effects of BoNT-A in dystonia; however, further validation in controlled studies is warranted.

Isolated Spinous Process Fracture: A Commonly Missed Diagnosis

BackgroundL4/L5 segment lumbar disc herniation and canal stenosis commonly cause low back and leg pain. Posterior interlaminar spine endoscopy has proven efficacy, but puncture positioning relies on experience and requires multiple fluoroscopic exposures, increasing operative difficulty and radiation exposure. This study proposes a vertebral anatomy-based puncture point(Yu Landmark) to assist puncture operations.MethodsA retrospective analysis of 426 L4/L5 posterior interlaminar spine endoscopy patients is conducted, divided into Yu landmark group (205 cases) and conventional group (221 cases). The Yu landmark determines the puncture entry point through the intersection of two lines under anteroposterior fluoroscopy: a vertical line from the midpoint of the L4 inferior articular process and a tangent line from the highest point of the junction between the L4 spinous process base and L4 lamina inferior edge. Puncture efficiency, fluoroscopic usage, complications, and clinical outcomes are compared between groups.ResultsThe Yu landmark group shows significantly reduced fluoroscopic exposures (4.9 ± 1.4 vs. 22.7 ± 4.8), radiation dose (0.48 ± 0.23 vs. 1.34 ± 0.29 mGy), and channel establishment time (22.6 ± 4.7 vs. 29.6 ± 5.9 min) (all P < 0.01), with higher single-puncture success rate (95.1% vs. 82.4%, P < 0.01). Early postoperative VAS and ODI improvements are better, while long-term outcomes and complications are similar.ConclusionsThe Yu landmark is simple, objective, and reproducible, significantly reducing fluoroscopic exposure while improving puncture efficiency, providing a standardized positioning strategy for L4/L5 posterior interlaminar endoscopic surgery.

The posterior minimally invasive approaches for odontoid fractures include the midline nuchal ligament approach (MNLA) and the paramedian muscle-splitting approach (PMSA). However comparative data on their anatomical characteristics and clinical efficacy remain scarce to date. The objective of this study is to determine the differences in anatomy and clinical outcomes between the MNLA and the PMSA for reduction and temporary internal fixation of odontoid fractures. This retrospective analysis focused on 31 patients with odontoid fractures from February 2021 to December 2023. Among them,16 patients underwent PMSA and 15 patients underwent MNLA. Various parameters were compared between the two groups, including operation time, intraoperative blood loss, postoperative complications, edema rates of cervical posterior muscles, the range of motion in rotation of C1-C2, patient satisfaction, Visual Analogue Scale score for neck pain, axial symptom scores, and neck disability index. Additionally, an anatomical study was performed; the PMSA and the MNLA were simulated on six fresh cadaveric specimens to compare the anatomical differences in surgical exposure between the two approaches. In the clinical study, both groups successfully achieved fracture healing. Compared with the PMSA group, the MNLA group had several advantages, including shorter operative times, lower intraoperative blood loss, and a lower edema rate of posterior cervical muscles. However, similar results were observed between the two groups in terms of the range of motion in rotation of C1-C2, patient satisfaction, Visual Analogue Scale score for neck pain, axial symptom scores, and neck disability index at the last follow-up. In the cadaveric study, we found the trapezius-splenius capitis interface and the course of the greater occipital nerve (GON) varied significantly and the GON was present in the surgical field in 2 of 6 specimens in the PMSA, which brought difficulties for the surgical operation. In contrast, the MNLA, using the spinous process of C2 and the obliquus capitis inferior (OCI) as anatomical landmarks, provided a simpler surgical procedure and easier exposure. Both the MNLA and the PMSA demonstrated favorable clinical outcomes for the treatment of odontoid fractures. However, compared with the PMSA, the MNLA, using the spinous process of C2 and the OCI as anatomical landmarks, offers advantages of the stability of the surgical procedure, easy exposure, and reduced iatrogenic damage to the cervical posterior muscles and GON.

This study aims to investigate how varying shoulder movement speeds affect spinal mobility to enhance understanding of the trunk's adaptive response to these perturbations. Eleven healthy participants were fitted with motion markers placed on the bilateral shoulders, upper extremities, and the spinous processes of the 8th thoracic vertebra (T8), 4th lumbar vertebra (L4), and the posterior superior iliac spine, representing the 2nd sacral vertebra (S2). Each participant performed bilateral forward shoulder elevation in the sagittal plane at three different speeds (natural, fast, and slow) in a randomized order. Each speed condition included five repetitions, with the middle three repetitions used for analysis. The peak-to-peak displacement and excursion of T8, L4, and S2 during the ascending and descending phases of shoulder elevation were recorded. Repeated measures one-way analysis of variance (ANOVA) and the Friedman test were applied to compare the effects of the three speeds. Significant differences were observed between the fast and slow speeds in the peak-to-peak displacements of T8 and L4 during the descending phase, as well as in the T8 excursion across the full range of forward shoulder elevation, or 31%, 24%, and 26% increase, with p-values of 0.045 (ES = 1.053), 0.042 (ES = 1.019), and 0.028 (ES = 1.174), respectively. No significant differences were detected at the S2 level. Spinal mobility during forward shoulder elevation was observed at fast speed, especially during the descending phase at the thoracic and lumbar levels. These speed-dependent changes are clinically critical, influencing movement control and trunk injury risk, especially during descent of forward shoulder elevation. The speed of shoulder movement should be considered during physical examination and intervention.

Optical 3D surface scanning is used increasingly to assess spinal deformity of patients with scoliosis. However, approaches based on optical 3D scanning often underestimate the spinal deformity. To improve the accuracy of such estimates, deeper understanding is required of scoliosis and its effect on the back shape. We present the PCdare research software which registers 3D surface scans with the corresponding biplanar radiographs semi-automatically and facilitates investigations into the relationship between surface and internal modalities. PCdare revealed very strong correlations between the spinous process line and internal spinal alignment, and a median Cobb angle difference of less than 1° from the clinical gold standard. These results increase confidence in the use of 3D scanning with a “back-shape-to-spine” approach and confirm the applicability of PCdare to investigate the relationship between internal alignment and back shape in research.

With increasing interest in artificial intelligence (AI) for veterinary medical imaging, there will be an increasing need for the segmentation of medical images. Image segmentation-the process of delineating anatomical structures in medical images-is a critical step for enabling analysis and decision support in veterinary radiology. Manual segmentation of medical images is a time-consuming and tedious task associated with user variation. Many segmentation tasks require a radiologist's expertise. To date, there have been limited evaluations of segmentation methods in veterinary medicine. It is unknown whether novice evaluators can segment radiographs with similar accuracy to experts. The present study aimed to evaluate the performance of an AI segmentation tool in enhancing the accuracy and reducing the time of canine radiograph segmentation of novice, intermediate, and expert users when using an internally developed software that allows both AI-assisted semiautomated and manual segmentation. The AI model was trained using 50 thoracic radiographs from patients referred to the Ontario Veterinary College between January 2020 and July 2021. The intersection over union scores (IoU) for the abdomen, heart, and spinous process labels were higher when all cohorts used the semiautomated method (0.98, 0.98, and >0.74, respectively) versus the manual method (>0.93, >0.94, and >0.42, respectively). The Hausdorff distance for the structure labels was significantly lower when the participants used the semiautomated method than the manual method (p<.0001). The intraobserver intraclass correlation coefficients (ICC) for the semiautomatic and manual methods were 0.81 and 0.36, respectively. In conclusion, the semiautomated tool effectively assisted users with segmenting canine thoracic radiographs.

BackgroundChronic low-back pain, a leading cause of global disability, is closely linked to intervertebral disc degeneration (IVDD). Traditional animal models have faced challenges in replicating the gradual, chronic nature of human IVDD.ObjectiveTo address these limitations, we aimed to develop a novel mouse model of cervical spine instability that more accurately mimics the progressive degeneration observed in humans.AnimalsThis study used 48 male Sprague–Dawley rats (3 months old, weighing 230 ± 20 g) and 48 male C57BL/6 mice (12 weeks old, weighing 20 ± 2 g).MethodsA bilateral cervical laminectomy combined with spinous process resection was performed while preserving the facet joints and posterior cervical muscles to induce chronic intervertebral instability. Longitudinal assessments were conducted using in vivo magnetic resonance imaging (MRI), histological staining (H&E and Safranin O-fast green), immunofluorescence and western blot analyses at 4, 8, and 12 weeks post-operation.ResultsMRI findings demonstrated progressive degeneration at the C4/5, C5/6, and C6/7 levels, with the most pronounced changes observed at 4 and 8 weeks post-surgery and partial recovery at 12 weeks. H&E and Safranin O staining confirmed significant cellular loss, structural disorganization, and proteoglycan depletion in the affected discs. Immunofluorescence staining revealed a progressive decrease in collagen type II and aggrecan expression over time. Conversely, collagen type I expression increased, indicating a shift toward fibrosis. Western blot analysis confirmed elevated levels of oxidative stress markers (albumin and AOPPs), matrix metalloproteinases (MMP3 and MMP13), senescence markers (p53, p21, p16), and inflammatory cytokines (IL-1β, TNF-α) at 4 and 8 weeks, with a partial decline by 12 weeks.ConclusionsThis innovative cervical instability model not only minimizes the risk of nerve injury and reduces animal stress compared to previous models but also offers a reproducible and ethically sound platform for investigating IVDD pathogenesis and testing potential therapeutic interventions.

Achondroplasia is the most prevalent form of skeletal dysplasia and is characterized by rhizomelia, short stature, and distinctive facial features. Achondroplasia is frequently accompanied by spinal canal stenosis because of the distinctive morphology of the spine. For pediatric lumbar spinal canal stenosis, a meticulously constructed surgical plan is needed to prevent complications such as the development of thoracolumbar kyphosis. An 11-year-old Asian boy with achondroplasia presented with bilateral lower limb numbness and intermittent claudication, which limited his walking distance to 100m. Imaging revealed multilevel lumbar spinal canal stenosis from T12 to S1, with the most stenosis at the L4/5 level. Laminotomy with spinous process reconstruction using mini plates was performed to preserve the midline posterior tension band. The patient's postoperative course was uneventful, with immediate symptom resolution and no symptoms of recurrence or signs of kyphotic deformity at the 2-year follow-up. Achondroplasia-associated lumbar spinal canal stenosis arises from anatomical constraints, such as shortened pedicles and short interpedicular distances. Surgical intervention must provide effective decompression without increasing the risk of postoperative thoracolumbar kyphosis. This case highlights the importance of preserving posterior elements that are responsible for maintaining spinal stability and the pertinence of avoiding extensive fixation, particularly in pediatric patients with achondroplasia. This case demonstrates that, in patients with achondroplasia, laminotomy with spinous process reconstruction can effectively address lumbar spinal canal stenosis and preserve posterior elements with a minimal risk of complications. Long-term follow-up remains crucial for monitoring the potential development of thoracolumbar kyphosis.

Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) and generalized arterial calcification of infancy (GACI) occur secondary to biallelic ectonucleotide pyrophosphate/phosphodiesterase 1 (ENPP1) loss-of-function pathogenic variants. GACI is a life-threatening condition, often presenting in the neonatal period with heart failure and hypertension, caused by calcification of the media in large- and medium-sized arteries. ARHR2 typically manifests later in life. Children with ARHR2 commonly exhibit short stature, rachitic skeletal changes, progressive deformities of the lower limbs, skeletal fragility and bone/muscle pain. We present six cases of homozygous pathogenic variants in the ENPP1 gene causing ARHR2 and/or GACI.Case 1: Presented with lower limb deformities and pain with radiological evidence of rickets. Subsequent investigations displayed aortic and pulmonary arterial calcification.Case 2: Presented with lower limb deformities and knee pain. Confirmatory testing was undertaken following her brother’s (Case 1) diagnosis.Case 3: The diagnosis was made antenatally. Bisphosphonate treatment was instituted in both the pre- and post-natal periods due to the presence of extensive arterial calcifications. Rickets were noted by two years of age.Case 4: Presented with lower limb deformities and pain. There is neither any current evidence of arterial calcification nor hypertension.Case 5: Presented at 3 mo of age in cardiogenic shock with widespread calcification of large and medium-sized arteries. Bisphosphonate treatment was instituted.Case 6: Presented at 2 wk of age with right shoulder discomfort, with evidence of glenohumeral joint calcification. Further imaging revealed aortic, mediastinal, sternoclavicular joint and vertebral spinous process calcification.Case 1 and 2 were also found to have a heterozygous pathogenic ALPL variant consistent with hypophosphatasia.Clinical features, biochemistry, imaging and genetic analyses assist in the diagnosis of ARHR2 and GACI. Conventional therapy, oral phosphate and calcitriol for ARHR2 and bisphosphonates for GACI, have been utilized for many years. ENPP1 replacement treatment remains an exciting prospect for future management of ARHR2 and GACI secondary to loss of function of ENPP1.

This retrospective clinical audit aimed to determine which peripheral nerve block approach to the femoral nerve had lower intraoperative drug requirements. A total of 30 hospital records for client-owned dogs undergoing hindlimb orthopaedic surgery were reviewed, and 23 were included in statistical analysis. Dogs were grouped as follows: pre-iliac femoral approach (group PI, n=11); or femoral triangle (group FT, n=9). In group PI, the block was performed by drawing a line from the spinous process of the 6th lumbar vertebra, perpendicular to the spine in a drso-ventral direction. A second line parallel to the spine was drawn from the most cranial aspect of the iliac crest until the lines intersected. In the FT group, the femoral nerve was approached by finding the femoral pulse and inserting the needle slightly cranial to this landmark. Both groups used electrostimulation to confirm correct insertion. Dogs were monitored intraoperatively and received a fentanyl constant rate infusion. Analysed data included: the type of surgery, the execution time, the intraoperative fentanyl concentration, the intraoperative isoflurane concentration and any prolonged neurological complications. There was no statistically significant difference between the average use of intraoperative fentanyl (µg/kg/h) in dogs that received the FT approach (median, IQR) (3.25, 2.77–4.63) compared with those that received a PI approach (2.94, 2.55–3.43) (U=40.0, P=0.159). There was no statistically significant difference between the average percentage of intraoperative isoflurane used throughout the procedure in dogs that received the FT approach (1.8, 1.61–2.02) compared with those that received a PI approach (2.94, 2.55–3.43) (U=58.0, P=0.781). No proprioceptive deficits were noted. Neither femoral nerve block technique offered a superior approach to the patient's analgesic plan. Further research is needed to draw definitive conclusions.

One motion, different strategies: Intra-individual spinal movement variability during a repeated flexion task.

Objectives: This study aimed to review and synthesize randomized controlled trials (RCTs) of acupotomy on tinnitus to clarify its therapeutic potential and provide a foundation for future research.Methods: A systematic literature search was conducted in seven databases (KCI, OASIS, RISS, KISS, Embase, Cochrane Library, and CNKI) for studies published between 2016 and August 2025. Eligible studies were RCTs employing acupotomy as an intervention for tinnitus. Study characteristics, treatment protocols, outcome measures, and methodological quality were analyzed. The risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool.Results: Six RCTs were included, most of which investigated cervicogenic tinnitus (n=4). In all trials, acupotomy was applied as a concomitant intervention. Frequently selected treatment points included tenderness nodules, the inferior nuchal line, and the spinous process of second cervical vertebrae. Intervention groups demonstrated higher effective rates and greater improvements in tinnitus questionnaires compared with control groups. Improvements in blood flow velocity were observed in some studies, although results were inconsistent. The methodological quality of included studies was generally rated as high risk due to insufficient randomization concealment, lack of blinding, and absence of protocol registration.Conclusions: Acupotomy may serve as a promising adjunctive therapy for tinnitus. However, future rigorously designed trials with validated outcome measures and acupotomy as an independent intervention are required to confirm these findings and elucidate its role in tinnitus management.

The effect of manual therapy on abdominal scars in patients with nonspecific chronic low back pain - a double-blind, randomized, and controlled study.

Study Design: Retrospective observational study. Objectives: To quantitatively assess contrast enhancement in five cervical extensor muscles in patients with dropped head syndrome (DHS) using gadolinium-enhanced magnetic resonance imaging (MRI), and to explore potential pathophysiological mechanisms based on enhancement patterns. Background: Dropped head syndrome (DHS) impairs forward gaze, significantly affecting daily activities and quality of life. Although MRI has proven useful in evaluating cervical extensor muscle dysfunction, a standardized quantitative analysis of contrast enhancement has not yet been established. Materials and Methods: Twenty-two patients with DHS and 20 control subjects without DHS underwent gadolinium-enhanced cervical MRI. Signal intensity was measured in five posterior neck muscles: trapezius, splenius capitis, rhomboid minor, semispinalis cervicis, and levator scapulae. Signal-to-noise ratios (SNR) and intensity ratios (IR), originally defined, were calculated and compared between the two groups. Results: The DHS group showed significantly higher SNR values in all five muscles compared with the control group, with the most pronounced differences observed in the splenius capitis and rhomboid minor ( P &lt; 0.01). The splenius capitis also demonstrated significantly higher IR values than the trapezius and levator scapulae ( P &lt; 0.05), indicating distinct enhancement patterns. Conclusions: Contrast-enhanced MRI revealed characteristic enhancement in the splenius capitis and rhomboid minor muscles in patients with DHS, suggesting inflammatory changes at the C6/C7 spinous process attachments. Milder enhancement in other extensor muscles may reflect stress-related changes due to cervical extension. The variability in rhomboid minor enhancement suggests the existence of pathophysiological subtypes within DHS.

ObjectivesClinical ultrasound provides a non-invasive method to assess spinal curvature in adolescent idiopathic scoliosis (AIS). However, the reliability and validity of ultrasound assessment may be affected by body mass index (BMI). This study investigated the impact of BMI on the reliability and validity of ultrasound assessments in AIS.Design165 participants with suspected AIS were recruited for both ultrasound and radiographic assessments. Lateral spinal curvature was measured on ultrasound imaging using the spinous process method and on X-ray using the Cobb method. The same operator performed two ultrasound scans for each participant, and two independent raters measured the images (Rater 1: 1st and 2nd scans; Rater 2: 1st scan only). Intra-operator and inter-rater reliabilities were assessed using intraclass correlation coefficients (ICCs), and validity was assessed by correlating ultrasound angles with Cobb angles using Pearson’s r. Participants were categorized by BMI tertiles and BMI-for-age percentiles for subgroup analyses.ResultsThe second BMI tertile (16.2–18.5 kg/m2) exhibited the highest reliability: ICC (2,1)=0.83 (95% CI: 0.73–0.90) intra-operator and 0.88 (95% CI: 0.76–0.94) inter-rater. By BMI-for-age classification, the normal-weight group demonstrated the highest reliability (ICC = 0.78 and 0.84) and the lowest standard error of measurement (2.6° and 2.3°). Validity was strongest in the 18.1–24.4 kg/m2 BMI group (r = 0.85), compared with 12.3–15.8 kg/m2 (r = 0.58) and 16.0–17.7 kg/m2 (r = 0.61).ConclusionsThe reliability of ultrasound assessments of spinal curvature was highest in adolescents in the second BMI tertile and in the normal-weight group, while underweight and overweight groups showed lower reliability. Correlation with Cobb angles was strongest in the 18.1–24.4 kg/m² BMI group (r = 0.85), suggesting ultrasound performs best when soft-tissue conditions are neither minimal nor excessive. These findings suggest that BMI should be considered when interpreting ultrasound measurements and when designing screening protocols for AIS.

The posterior layer of the thoracolumbar fascia, which includes the aponeuroses of several skeletal muscles among its components, has long been of interest in relation to low back pain. This layer has been described as consisting of two laminae, a superficial and deep. These laminae are known to fuse tightly at a lower thoracic level, forming a unified posterior layer. However, the precise anatomical continuity of these components, particularly in the lower lumbar and sacral regions, remains unclear. Therefore, we performed a comprehensive macroscopic analysis of the posterior layer, focusing on the composition and orientation of collagen bundles (CB) within the aponeurosis of its component muscles, while taking anatomical variations into account. We examined 17 sides from 11 cadavers, focusing on the lumbar to the upper sacral vertebral region. In all specimens, no distinct retinacular sheet could be separated from the aponeurotic complex of the posterior layer, even in the lower lumbar and sacral regions where previous studies illustrated a deep lamina. In the upper lumbar region, the aponeuroses of the latissimus dorsi (LD) and serratus inferior muscles contributed to the posterior layer, forming a continuous structure that could not be divided into distinct layers. Meanwhile, in the lower lumbar region, the posterior layer comprised the aponeuroses of the LD and internal oblique muscles, along with a bundle of fibers extending from the periosteum of the iliac crest. In the upper sacral region, the posterior layer comprised the aponeurosis of the LD, erector spinae, and gluteus maximus muscles, together with the bundle of fibers from the periosteum of the iliac crest. Despite some variations in the site of muscle attachment, the posterior layer consistently contained CB that are inferolaterally oriented from the lumbar to iliac crest spinous processes between the lumbar and upper sacral vertebrae, in a direction independent of the orientation of muscular aponeuroses. These consistent directional patterns may suggest a functional integration of muscular and fascial components, regardless of anatomical variation. Considering the structural features of the posterior layer, further studies are needed to clarify how dynamic changes in this layer during trunk movement may contribute to clinical conditions, including low back pain.

Although endoscopic spine lumbar interbody fusion (Endo-LIF) is widely applied clinically, it still presents several shortcomings, including intraoperative disorientation, a high rate of nerve injuries, a steep learning curve, and extended operation times. There is a lack of quantification regarding the standards of surgical operations. Consequently, the standardization and quantification of surgical procedures are poised to become focal points for future research on Endo-LIF. The intervertebral spaces from L1 to L5 were selected, and three-dimensional (3D) computed tomography (CT) employed to identify Kambin's triangle and the inscribed circles within it. The angle "α" formed by the line connecting the center of the circle "O" to the center of the intervertebral disc "A" was recorded, as was the line connecting "A" to the center of the spinous process "B". This angle represents the approach angle of the visible trephine during surgery. Additionally, in the Mimics software 3D model, abrasion of the facet joints was observed when the visible trephine was positioned at the angle "α". The abduction angle of the visible trephine in each intervertebral space from L1 to L5 exhibited a gradually increasing trend. When applying the trephine, the L1-L2, L2-L3, and L4-L5 intervertebral spaces showed measurements of 0°-31.35° (± 2.78), 0°-30.93° (± 2.80), and 0°-33.01° (± 3.49), respectively. Notable discrepancies were observed in the L3-L4 intervertebral space; specifically, the left side measured 0°-29.93° (± 0.75), while the right side measured 0°-32.01° (± 0.51). The authors believe that this study provides surgeons with an effective reference by significantly reducing time wasted due to improper trephine placement, shortening operative duration, and alleviating patient discomfort. Furthermore, by adhering to the quantified trephine placement angle, surgeons can perform procedures with more standardized and normative data guidance and substantially enhanced surgical safety. Finally, this study can be an important clinical reference for future research in path planning and precision operations in spinal surgery robotics.

A healthy posture is characterized by symmetric features like equal shoulder height, a straight spinous process line and equally-sized waist triangles. Deviations suggest spinal disorders, among them adolescent idiopathic scoliosis (AIS), a three-dimensional spinal curvature requiring timely treatment. AIS screenings are debated among the scientific community. This study proposes two symmetry-sensitive convolutional neural networks (CNNs) to identify asymmetries in videorasterstereographic back curvature images to classify AIS. A total of 1444 videorasterstereographic measurements were collected from individuals (11 ± 2.4 years), among them 355 with AIS, 306 with other spinal deformities and 783 with healthy posture. Two types of curvature images, Mean and Gauss, were compared using a VGG16 network and a two-channel CNN based on DeepSymNet. The latter analyzes left and right side of the torso image separately, then merges the results and identifies asymmetries. Both models achieved accuracies between 0.768 and 0.801 during validation, the accuracy of the test set of the tuned DeepSymNet (five repeated trials) was 0.744 ± 0.014, specificity was 0.748 ± 0.025, sensitivity 0.726 ± 0.044 and PPV 0.417 ± 0.013. The equal performances show models were able to learn symmetry, making both suitable for training videorasterstereographic images. The main benefit and greatest challenge was the dataset diversity, which incorporated a variety of postural conditions, confounding AIS features. Adapting CNNs to include symmetry analysis could be an improvement to other known applications of deep learning in spinal deformity analysis. Refining the dataset to incorporate more mild cases could enhance the performance of DeepSymNet in particular. With these modifications, DeepSymNet as well as VGG16 are promising approaches for future AIS screenings.