We explain the robotic-assisted screw placement and its accuracy in spinal deformity surgery. We will focus on the issue of "Shift and Skive" and explain measures to improve screw accuracy.

Our facility uses a CT-to-Fluoro workflow using Mazor X Stealth Edition. The robot arm automatically moves along the preoperatively planned trajectory and places the screw under the arm guide. However, screw placement has the issue of "Shift and Skive", and measures are needed to overcome these problems.

"Shift" refers to the change in the relationship between the patient's bone and the robotics system after registration. "Skive" refers to the change in direction and position of the surgical instrument under the robot arm guide. To deal with these issues, there are methods to deal with shift, such as adjusting the order of screw placement. Also, the use of a high-speed drill is very effective as a countermeasure against instrument skiving.

Introduction: Neuromuscular scoliosis tends to progress rapidly and is associated with fatal respiratory failure in severe case. One of the causes of death is tracheal stenosis, but the radiological factors related to tracheal stenosis among neuromuscular scoliosis are unknown.

Methods: Seventeen neuromuscular patients with paralytic disease (cerebral palsy in 11 patients, spinal muscular atrophy in 3, muscular dystrophy in 2, and adrenoleukodystrophy in 1) were included this study. Tracheal stenosis was defined as narrowing of the main and lobe bronchi, and was evaluated on CT reconstruction images. Measurements included Cobb angle, thoracic kyphosis angle (T1-12), tracheal stenosis rate, presence of compression by the aorta or innominate artery, distance between the tracheal stenosis vertebra and rib, lateral deviation of the compressed vertebra from the sternal vertebral body center, and thorax aspect ratio.

Results: The mean age at the time of the study was 15 years (6-21), the mean scoliosis Cobb angle was 97 degrees (39-137), the mean thoracic kyphosis angle was 18 degrees (-20-74), the mean tracheal stenosis rate was 26% (0-76), and T6 was the most common vertebra directly involved in tracheal compression. Comparing the groups with and without tracheal stenosis, there were significant differences in the reduction of thoracic kyphosis angle and decrease in the thoracic aspect ratio, while there was no significant difference in the scoliosis Cobb angle.

Conclusions: In neuromuscular scoliosis, factors associated with tracheal stenosis included a reduced thoracic kyphosis angle and a decreased thorax aspect ratio, indicating a "thin thorax".

Introduction: The purpose of this study is to investigate the surgical outcomes and perioperative complications of posterior spinal fusion performed by dual attending surgeon for NMS associated with severe cerebral palsy.

Methods: Thirty-one patients who underwent spinal fusion for NMS were included. The group D (12 cases) was dual attending surgeon, and the group S (19 cases) was single surgeon. Surgical outcomes and perioperative complications were retrospectively compared between two groups.

Results: The mean age at surgery was 16 years old in group D and 15 years old in group S (P<0.05). The preoperative Cobb angles of main curve were 133 degrees in group D and 106 degrees in group D (P<0.05). The average operation time was 212 minutes in group D and 487 minutes in group S (P<0.01). The postoperative correction rate of the main curve was 41% in group D and 57% in group S, which was significantly lower in the D group (P<0.01), but there is no difference in the gain of T1-12 height. Perioperative complications were observed in 4 patients (33%) in group D and 16 patients (84%) in group S, and the number of perioperative complications was significantly lower in group D (P<0.01).

Conclusions: Posterior spinal fusion by dual attending surgeon for NMS associated with severe cerebral palsy was able to greatly shorten the operative time and reduce perioperative complications. However, the more severe the scoliosis, the lower the correction rate, and the pelvic obliquity remained, therefore surgical intervention was considered necessary before the curve became severe.

Introduction: We investigated the impact of reduced school scoliosis screenings due to the COVID-19 pandemic on scoliosis management.

Methods: The subjects were 104 patients who initially visited the scoliosis outpatient clinic (outpatient clinic group) and 720 participants who underwent school screening (school screening group) from January 2017 to March 2022. We studied the age and radiographic findings at the initial visit in both group. We compared these findings before the COVID-19 pandemic (before March 2020) and after the pandemic began (after April 2020).

Results: In the outpatient clinic group, the average age was higher after the pandemic (before the pandemic 12.7±1.5 years vs. after the pandemic 13.4±2.2 years, P=0.0434). The percentage of patients with a Cobb angle of 20-24° at their initial visit, considered borderline for treatment, decreased after the pandemic (before the pandemic 18.2% vs. after the pandemic 7.9%, P=0.0437). In the school screening group, the average number of participants decreased (before the pandemic 159.7 people/year, after the pandemic 120.5 people/year), and the average Cobb angle increased (before the pandemic 11.2±6.9°, after the pandemic 15.3±8.1°, P=0.0002).

Conclusion: Due to the COVID-19 pandemic, early detection of scoliosis may have been delayed and the optimal timing for treatment may have been missed.

Introduction: Surgical treatment of adolescent idiopathic scoliosis (AIS) is generally recommended for patients with a thoracic or lumbar curve >40 degrees. However, the reasons and concerns of patients with AIS and their parents regarding surgery are unclear. This study aimed to elucidate the reasons and concerns for AIS surgery among patients and their parents, and to investigate the differences in reasons and concerns between patients and their parents. Before starting this study, we hypothesized that there were differences between patients with AIS and their parents in their reasons and concerns regarding AIS surgery.

Methods: Patients with AIS and their parents completed a comprehensive survey independently before the surgery. The survey consisted of thirteen reasons and nine concerns for AIS surgery, which the patients and parents were asked to rank from 1^st to 3^rd. Answers were scored as follows: 1^st, 1 point: 2^nd, 2 points; 3^rd, 3 points; and no ranked questions, 10 points. We calculated the ranking points for each question. The lower ranking point of a question demonstrated more expectation and concern issues. Furthermore, the number of answers ranked from 1^st to 3^rd were counted among the rankings provided by patients and parents. We analyzed the data with Man-Whitney U-test and Chi-square test.

Results: Overall, 18 patients with AIS and their parents completed the survey. Prevention of further progression was the strongest reason among patients and their parents, while neurological deficit was the strongest concern among patients with AIS and their parents. Although there was no statistically difference, patients cited waistline asymmetry as the reason and they were concerned about the immediate postoperative pain more than parents. Meanwhile, parents felt more concerned about neurological deficit than patients (p < 0.05).

Conclusions: Preoperatively, spine surgeons should provide adequate information regarding the indication or complications of surgery to patients with AIS and their parents. Although some minor differences were apparent between parents and patients, the strongest reason and concern were the same. We believe that our findings will be useful for spine surgeons as they would inform to the patients and parents, and aid in the preoperative planning of corrective surgery for patients with AIS.

Introduction: Neuromuscular scoliosis associated with spina bifida and myelomeningocele is a progressive disease that starts from birth and continues beyond maturity. Scoliosis and kyphosis are the main pathological issues brought on concerning the spine by this condition. Complex cases are challenging to treat without surgical intervention, but early surgeries pose many adverse risks. This study aimed to investigate surgical outcomes of patients with spina bifida and myelomeningocele who underwent Vertical Expandable Prosthetic Titanium Rib (VEPTR) surgeries for spinal deformity control.

Subjects and Methods: Retrospective Study. 17 patients (10 males, 7 females) met the inclusion criteria: a) patients who underwent VEPTR treatments for spinal deformity associated with spina bifida and myelomeningocele, and b) patients who have undergone final fusion. We evaluated demographics and spinal parameters at the first presentation, pre- and post-initial VEPTR and final fusion surgeries.

Results: The mean age at the time of initial VEPTR surgery was 6.1 years old, preoperative height 95.1 cm, and weight 13.6 kg. Scoliosis improved from 73.6 pre-VEPTR to 53.0° post-initial VEPTR and 53.1° post-final fusion, while kyphosis improved from 123°pre to 61.4° post-initial VEPTR and 40.4° post-final fusion. Preserved T1-T12 thoracic vertebra height was 2.4 cm, and the T1-S1 height was 4.2 cm.

Conclusion: VEPTR treatment delayed final fusion surgery by 5.2 years. Whilst correction of scoliosis and kyphosis was possible, despite the number of additional surgeries performed, the effect on growth preservation of the spinal column was limited.

Introduction: The Dunn-McCarthy (D-M) technique is a method for correcting kyphotic deformities of the spine. This method is commonly utilized to correct angular kyphosis in individuals with spina bifida and myelomeningocele. We reviewed the postoperative outcomes of 16 patients who underwent corrective lumbosacral fixation using the D-M technique for these conditions.

Methods・Result: The mean age at the time of surgery was 8.7 years, with a mean follow-up of 5 years. The mean kyphosis was 146.0° preoperatively. Intraoperative complications occurred in 6 patients, and postoperative complications occurred in 15 patients. Mean kyphosis was 52.5° postoperatively, and 58.5° at the final follow-up.

Discussion: Due to its S-shaped design of the rods, the D-M technique allows for an effective kyphosis correction via its unique mechanical advantage. Corrective surgery for angular kyphosis associated with spina bifida and myelomeningocele is often difficult to treat due to complications such as loss of correction, infection, and nonunion. The D-M technique is one option for the correction and stabilization among patients with angular kyphosis due to myelomeningocele.

Introduction: School screenings have increased the chances of patients with mild scoliosis visiting an outpatient clinic. We are actively treating scoliosis of 30 degrees or less using night braces, which we consider to be relatively less burdensome for patients. In this study, we report on the results of treatment in these cases.

Methods: We treated 37 females with idiopathic scoliosis of 30 degrees or less using the Semoto-Nagano night brace, and examined the results of treatment in cases more than 2 years after removal of the brace. The average age before brace treatment was 13 years and 4 months, the average period of wearing braces was 2 years and 4 months, and the follow-up period averaged 4 years and 11 months. The average number of years after removal of the brace was 2 years and 8 months. The change in curvature due to the brace was investigated for the group in which the Risser sign was 0 to 2 at the start of the brace treatment, the Risser sign 3 group, and the Risser sign 4 group. The average Cobb angle before treatment in the Risser sign 0-2 group was 20.4 degrees, the average Risser sign 3 group was 19.6 degrees, and the average Risser sign 4 group was 20.1 degrees.

Results: If the Cobb angle decreases by 5 degrees or more, it is improved, if it increases or decreases within 5 degrees, there is no progress, and if it increases by 5 degrees or more, it progresses. In the Risser sign 0-2 group (16 cases), 11 cases improved, 3 cases did not progress, and 2 cases progressed. In the Risser group 3 (9 cases), 4 cases improved 44.4%, 3 cases did not progress 33.3%, and 2 cases progresses 22.2%. In the Risser group 4 (12 cases), 2 improved (16.7%), 7 did not progress (58.3%), and 3 progressed (25%).

Discussion: Although there are many papers that full-time braces are effective in preventing progression, there are few that follow up on the results of night braces more than two years after the end of treatment. In the results of this survey, progression was prevented in 87.5% of cases with Risser 0-2, and progressing in 12.5%. If treatment is started early, progression can be prevented even night-time brace. It is also noteworthy that 4 cases (25%) improved by 10 degrees or more with night braces. This overturns the conventional wisdom that braces can only prevent progression, and suggests that the curvature can be improved by starting treatment early. In addition, there were 3 cases (25%) in which even Risser 4 progressed. There is a risk to decide the indication of the brace only by the Risser sign.

Conclusion: 1. We report the outcome of idiopathic scoliosis using Semoto-Nagano Night Brace. 2. Even brace worn only at night are effective in preventing progression. When Cobb angle is under 20 degrees, night-time brace should be started immediately rather than waiting until it progresses.

Introduction: Postural balance is crucial in scoliosis patients due to reduced balance control leading to fatigue and pain. Static indicators like plain X-rays are insufficient; thus, postural stability evaluation using a gravity sway meter is recommended. The index of posture stability (IPS) is a useful indicator for evaluating posture stability in scoliosis patients, but there have been no reports of its application to patients undergoing scoliosis surgery. This study aimed to assess changes in postural stability using IPS in scoliosis surgery patients pre- and post-operatively.

Methods: Twenty-three patients who underwent scoliosis surgery between April 2021 and August 2023 were evaluated just before and one month after surgery using a gravity sway meter. IPS was calculated based on previous reports, and postoperative changes in IPS were categorized into improved, unchanged, or worsened groups for comparison.

Results: Of the 23 patients, 18 had idiopathic scoliosis, and the rest had syndromic scoliosis. There were no delays in intellectual development. Preoperative Cobb angle averaged 57.2°, reduced to 13.9° postoperatively, with a correction rate of 77.6%. Postoperative postural stability improved in 6, remained unchanged in 12, and worsened in 5. Only preoperative IPS showed a significant difference among the groups.

Conclusion: Preoperative postural balance in scoliosis patients was worse compared to healthy individuals. While factors influencing postoperative balance improvement or deterioration remain unclear, not all patients experienced a decline postoperatively.

Introduction: Radiographic measurement is essential in treating scoliosis; however, manual measurements come with intra/ inter-rater errors (ranging from 3 to 8 degrees) and labor required. The development of AI using deep learning technology to automate these measurements is advancing. This study aimed to develop an AI capable of automatically measuring frontal whole-spine X-rays of adolescent idiopathic scoliosis patients using a large dataset.

Methods: This study used 2,059 whole spine X-rays of adolescent idiopathic scoliosis patients. Key points were marked at four corners of vertebral bodies, sacrum, pelvis, clavicle, and femoral heads, which were decided as "ground truth." Deep learning was employed to develop an AI model, and parameters, including the Cobb angle, were measured. Five-fold cross-validation was made to evaluate the accuracy of AI measurement.

Results: The AI demonstrated high accuracy in measuring the Cobb angle, with a mean absolute error of 2.5° and a correlation coefficient of 0.99 for major curves. As training progressed, the model could identify vertebral corners accurately, even when overlapping with implants. The measurement time per image was only 1.4 seconds.

Conclusions: Training with a large dataset makes it possible to accurately measure the spinal parameters of adolescent idiopathic scoliosis patients, even with implants. Measurement time was short enough, highlighting the potential of AI as an extremely useful tool in clinical settings.

Introduction: Most studies to date of the natural course of adolescent idiopathic scoliosis (AIS) focused on the curve progression from skeletal maturity to adulthood, whereas few analyzed radiographic changes in coronal and sagittal alignments and curve flexibility during adulthood. This study aimed to reveal changes in scoliosis, curve flexibility, and sagittal alignment during middle age in patients with nonoperatively treated AIS.

Subjects and Methods: This study included 27 female patients with nonoperatively treated AIS (magnitude >30° at skeletal maturity) who visited our hospital at least twice after 30 years of age at an interval of >1 year. Coronal and sagittal alignments were evaluated on standing whole-spine radiographs, while curve flexibility, L4/5 disc wedging, and lateral lumbar (L1-5) range of motion (ROM) were evaluated on supine spine-bending radiographs. Parameters were compared between the initial and final visits using the Wilcoxon rank-sum test. Differences were considered significant at p < 0.05.

Results: The mean age was 40.7 (range, 30-58) years at the initial visit and 46.3 (range, 36-64) years at the final visit. The mean follow-up duration was 5.8 (range, 1.6-7.7) years. Curve magnitude did not change significantly during follow-up, changing from 24.0° to 24.0° for the upper thoracic curve (p = 0.78), from 54.0° to 55.0° for the main thoracic curve (p = 0.70), and from 44.0° to 50.0° for the TL/L curves (p = 0.95). UT and MT curve flexibility did not change significantly, while TL/L curve flexibility significantly decreased from 44.5% to 41.2% (p = 0.03). L4/5 disc wedging flexibility and lateral lumbar ROM did not change significantly (p > 0.3). Regarding sagittal alignment, lumbar lordosis decreased significantly from 51.0° to 39.0° (p < 0.001), while the sacral slope decreased significantly from 33.0° to 31.0° (p = 0.004). In contrast, the sagittal vertical axis increased significantly from −9.2 mm to −8.8 mm (p = 0.016), while pelvic tilt increased significantly from 13.0° to 17.0° (p<0.001).

Conclusions: Here we demonstrated the 6-year natural course of nonoperatively treated AIS during middle age and found no significant changes in coronal curve magnitude but significant decreases in TL/L curve flexibility. Significant decreases in lumbar lordosis and pelvic retroversion were observed in the sagittal plane. These findings suggest that TL/L curve flexibility and sagittal alignment as well as coronal curve magnitude should be monitored during middle age.

Introduction: In the current study, focusing on the difference between trunk muscle and appendicular skeletal muscle, the relationships between spinal coronal alignment and muscle mass including trunk muscle mass and appendicular skeletal muscle mass were elucidated.

Methods: 196 AIS girl patients whose bone maturation we considered complete were included. Body composition including appendicular skeletal or trunk muscle mass corrected by the square of height were measured using bioelectrical impedance analysis. Further, Cobb angle and several spinal coronal alignment parameters including L4 Tilt, C7-Central sacrum vertical line (CSVL), and radiographic shoulder height (RSH) were also measured. Then we evaluated correlations among these measurements using Spearman's correlation coefficient. Additionally, we defined L4Tilt≥10 degrees and/or C7-CSVL≥20 mm and or RSH≥15 mm as spinal coronal malalignment and divided into normal alignment group and coronal malalignment group. Measurements were compared between 2 groups and associated factors of spinal coronal malalignment were evaluated by multiple logistic regression analysis.

Results: There were significant positive correlations between Cobb angle and RSH, age and corrected appendicular skeletal muscle. By contrast, age was negatively correlated with corrected trunk muscle. Further, higher Cobb angle and lower trunk muscle mass in coronal malalignment group were observed compared with those in normal group. In addition, Cobb angle as well as corrected trunk muscle mass were significantly associated with spinal coronal malalignment in multiple logistic regression analysis.

Conclusions: These findings indicated that higher Cobb angle and lower trunk muscle mass might be associated with spinal coronal malalignment in AIS patients.

Introduction: Recently, hand or thumb skeletal maturity systems such as Simplified Skeletal Maturity Index (SSMS) or Thumb Ossification Composite Index (TOCI) have been paid to attractive attention to predict the occurrence of peak height velocity (PHV) in adolescent idiopathic scoliosis (AIS). Newer imaging modalities such as ultrasound evaluation on bone age has been growing popularity in the pediatric endocrinology, providing on-the-spot, easy-to-read, and immediate results without exposing ionizing X-ray radiation. This study aims to compare the thumb skeletal maturity stage between radiograph and ultrasound assessment in patients with AIS.

Methods: Fourteen patients with AIS were enrolled. Mean age, initial Cobb angle were 13.4 years and 17.5 degree, respectively. The central portion of the thickness in proximal and distal phalangeal epiphyses were measured using radiograph or ultrasound evaluation. The correlation between X-ray and ultrasound assessment was investigated. Additionally, concordance ratio detecting the thumb maturity stage were investigated between the two modalities.

Results: The mean proximal and distal phalangeal epiphyses were 3 mm and 2.47 mm using X-ray, whereas those were 3.12 mm and 2.56 mm using ultrasound, respectively. The correlation coefficient was 0.90 in proximal phalangeal epiphysis and 0.88 in distal phalangeal epiphysis, respectively. The rate of concordance between radiograph and ultrasound assessment in TOCI classification was 95.0% (20/21).

Conclusions: Ultrasonographic assessment of the thickness of thumb phalangeal epiphyses were non-invasive, accurate, and useful tool for evaluating the degree of skeletal maturity, contributing to predict the timing of PHV or brace weaning in patients with AIS.

Introduction: Adolescent idiopathic scoliosis (AIS) is the most ordinary pediatric spinal disease. Timely intervention in growing individuals, such as brace treatment, relies on early detection of AIS. We developed a system consisting of a 3D depth sensor and an algorithm installed in a laptop computer. In this system, the correlation between the actual Cobb angle and the predicted Cobb angle calculated from the asymmetry index was 0.85 (P < 0.01). The purpose of this study is to create a deep learning algorithm (DLA) to identify moderate or severe AIS patients requiring the secondary screening using data of subjects detected in the school screening.

Materials and Methods: We included 334 subjects detected using the 3D depth sensor system in school screening. The 3D images from the 3D depth sensor system were used as input data for the DLA with Convolutional neural networks. We randomly separated the 334 subjects into an internal validation data of 250 and an external validation data of 84. Binary classification was performed as 0 for images with Cobb angle of < 12° and 1 for images with Cobb angle of ≥ 12° based on the average actual Cobb angle of 12.0°. Five-fold cross validation was conducted to evaluate the probability for Cobb angle of ≥ 12°. The minimum predicted probability in subjects with Cobb angle of ≥ 15° was configured as the cut-off value to detect the second screening targets. In the external validation, 84 images were evaluated utilizing trained DLA in the internal validation, and decide to require secondary screening, based on the cu-off value.

Results: In internal validation, the five-fold cross validation showed that the dataset 3 had the highest predicted performance. The minimum predicted probability in subjects with Cobb angle of ≥ 15° was 0.47 in dataset 3. In the external validation, the number of subjects with Cobb angle of < 10° and < 15° were 36 and 62, respectively. Based on a cut-off value of 0.47, 39 (63%) subjects with Cobb angle of < 15° were judged as unnecessary for the second screening. There was only one false negative case with Cobb angle of 19°.

Conclusions: This DLA reduced the number of extremely mild AIS patient and false positive cases in the external validation, indicating that this DLA can reduce the unnecessary medical care expenditures and the unnecessary radiation exposure for children and adolescents.