Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of unknown etiology that commonly affects adolescents, imposing significant socioeconomic burdens. Effective management necessitates a comprehensive approach that takes into account multiple factors, including growth potential and psychological issues. Despite significant advancements in AIS management, several questions regarding optimal treatment strategies persist. Recent technological advancements are transforming the treatment landscape, encompassing advancements in bracing, robotic-assisted deformity corrections, and other interventions. This review explores current issues debated in the literature concerning the treatment of AIS, focusing on contemporary high-level evidence (e.g., meta-analyses and randomized controlled trials). Furthermore, this review explores cutting-edge developments and future directions in AIS management, including the integration of artificial intelligence and augmented reality.

Methods: We reviewed consecutive patients with Lenke 1 AIS who underwent STF from 2000 to 2017. The patients were divided into two groups based on the surgical strategy used: low-density (LD) construct without DVR of the LIV (LD group) versus HD construct with DVR of the LIV (HD group). We collected data on the patient’s demographic characteristics, skeletal maturity, operative data, and measured radiological parameters in the preoperative and final follow-up radiographs. The occurrence of adding-on (AO) and coronal decompensation was also determined. Results: In this study, 72 patients (five males and 67 females) with a mean age of 14.1±2.3 years were included. No significant differences in the demographics, skeletal maturity, and Lenke type distribution were observed between the two groups; however, the follow-up duration was significantly longer in the LD group (64.3±25.7 months vs. 40.7±22.2 months, p <0.001). The HD group had significantly shorter fusion segments (7.1±1.3 vs. 8.5±1.2, p <0.001) and a more proximal LIV level (12.1±0.9 vs. 12.7±1.0, p =0.009). In the radiological measurements, the improvement of LIV+1 rotation (Nash–Moe scale) was significantly larger in the HD group (0.53±0.51 vs. 0.21±0.41, p =0.008). AO and decompensation occurred in 7 (9.7%) and 4 (5.6%) patients in the HD and LD groups, respectively, without any significant difference between the two groups. Conclusions In this study, the HD group had a significantly shorter fusion level and a more proximal LIV than the LD group; however, the two groups had similar curve correction and adverse radiological outcome rates.

Background: To overcome several disadvantages of conventional laminectomy for degenerative lumbar spinal stenosis (DLSS), several types of minimally invasive surgery have been developed. The purpose of the present study was to report the clinical and radiological mid-term outcomes of spinous process-splitting decompression (SPSD) for DLSS. Methods: Seventy-three consecutive patients underwent SPSD between September 2014 and March 2016. Of these, 42 (70 segments) who had at least 5 years of follow-up were analyzed retrospectively. The visual analog scale for back pain and leg pain, Oswestry disability index, and walking distance without resting were scored to assess clinical outcomes at the preoperative and final follow-up. A subgroup analysis was performed according to the union status of the split spinous processes (SPs). For radiological outcomes, slip in the neutral position as a static parameter, anterior flexion-neutral translation, and posterior extension-neutral translation as a dynamic parameter were measured before and at the final follow-up after surgery. Spinopelvic parameters were also measured. Reoperation rate at the index levels was investigated, and predictive risk factors for reoperation were evaluated using multivariate logistic regression. Survival analysis was performed with reoperation as the endpoint to estimate the longevity of the SPSD for DLSS. Results: All clinical outcomes improved significantly at the final follow-up compared to those at the initial visit (p < 0.05). The clinical outcomes did not differ according to the union status of the split SP. There were no cases of definite segmental instability and no significant changes in the static or dynamic parameters after surgery. Sacral slope and lumbar lordosis increased, and pelvic tilt decreased significantly at the follow-up (p < 0.05), despite no significant change in the sagittal vertical axis. The mean longevity of the procedure before the reoperation was 82.9 months. Five patients (11.9%) underwent reoperation at a mean of 52.2 months after the SPSD. There were no significant risk factors for reoperation; however, the preoperative severity of foraminal stenosis had an odds ratio of 7.556 (p = 0.064). Conclusions SPSD for DLSS showed favorable clinical and radiological outcomes at the mid-term follow-up. SPSD could be a good surgical option for treating DLSS.

Spinal metastasis is a common issue causing significant pain and disability in cancer patients. A multidisciplinary approach consisting of chemotherapy, radiotherapy, and surgical treatment is used for treating patients with metastatic spinal tumors. Due to recent advancements in medical and radiation oncology, like tumor genetics and stereotactic radiotherapy, this treatment strategy would change inevitably. Therefore, the decision-making systems developed for assisting physicians and surgeons to choose the most appropriate treatment for each patient with spinal metastasis need to evolve. In this review, the recent developments, validations, and modifications of these systems, as well as suggestions for future systems have been discussed. Recently, separation surgery combined with stereotactic radiotherapy (hybrid therapy) has gained popularity. Additionally, the evidence for hybrid therapy presented in the literature has been reviewed.

Background: Recombinant human bone morphogenetic protein-2 (BMP-2) is an osteoinductive growth factor widely used in orthopedic surgery; it is also known to be associated with postoperative airway compromise or dysphagia when applied to anterior cervical discectomy and fusion (ACDF). However, there have been no reports on ACDF using Escherichia coli-derived BMP-2 (E.BMP-2) with hydroxyapatite (HA). This pilot study aimed to investigate the potential efficacy and safety of E.BMP-2 using HA as a carrier in ACDF prior to designing a larger-scale prospective study. Methods: Patients eligible for inclusion were those who underwent ACDF using 0.3 mg of E.BMP-2 with HA per segment for degenerative cervical disc disease between August 2019 and July 2020 and had at least 1 year of follow-up. Fusion rates were analyzed using computed tomography or flexion-extension radiographs. Visual analog scales for neck pain and arm pain and neck disability index were measured preoperatively and the final follow-up. In cases of cervical spondylotic myelopathy, modified Japanese Orthopaedic Association scores were also evaluated. Postoperative complications such as airway compromise, dysphagia, wound infection, neurologic deficit, hoarseness, heterotopic ossification, seroma, and malignancy were investigated. Results: A total of 11 patients and 21 segments were analyzed. All clinical outcomes significantly improved at the final follow-up compared with the preoperative indices (p < 0.05). Only 1 case of dysphagia and no cases of airway compromise, wound infection, neurologic deficit, hoarseness, heterotopic ossification, seroma, or malignancy were observed during the follow-up period. Of the 21 segments, 15 segments showed solid fusion at 3 months after surgery, 4 segments at 6 months, and 1 segment at 12 months. Only 1 segment showed pseudoarthrosis, resulting in a fusion rate of 95.2%. Conclusions The outcomes of ACDF could be enhanced using 0.3 mg of E.BMP-2 with HA per segment. Based on this study, larger-scale prospective studies can be conducted to evaluate the efficacy and safety of E.BMP-2 in ACDF.

Background: This study aimed to analyse the trends in changes of radiologic parameters according to age to predict factors affecting the progression of thoracolumbar kyphosis (TLK). Methods: Records of patients with achondroplasia were retrospectively reviewed from July 2001 to December 2020. We measured imaging parameters (T10–L2 angle, sagittal Cobb angle, width, height, and number of wedge vertebrae, and apical vertebral translation [AVT]) of 81 patients with radiographically confirmed TLK. Based on the angle on X-ray taken in 36 months, 49 patients were divided into the progression group (P group, TLK angle ≥ 20°) and resolution group (R group, TLK angle < 20°). The mean values between the groups were compared using Student t-test, and the pattern of changes in each radiologic parameter according to age was analysed using a generalized estimating equation. Results: Some imaging parameters showed significant differences according to age between P group and R group: T10–L2 angle (p < 0.001), sagittal Cobb angle (p < 0.001), AVT (p = 0.025), percentage of wedge vertebral height (WVH) (p = 0.018), and the number of severely deformed wedge vertebral bodies (anterior height less than 30% of posterior) (p = 0.037). Regarding the percentage of wedge vertebral widths (superior and inferior endplates), the difference between the two groups did not significantly increase with age, but regardless of age, it was higher in P group than in R group. Conclusions The difference in the TLK angle between P group and R group of the achondroplasia patients gradually increased with age. Among the imaging parameters, AVT and WVH could be factors that ultimately affect the exacerbation of kyphosis as the difference between the groups increased significantly over time.

Background: Oblique lateral interbody fusion (OLIF) involves the antepsoas approach and psoas major muscle (PMM) retraction to insert the interbody cage orthogonally. Therefore, OLIF is often associated with postoperative anterior thigh pain (ATP) on the approach side. However, there is limited evidence on the nature and risk factors of ATP following OLIF. Methods: Consecutive patients who planned to undergo minimally invasive OLIF and percutaneous pedicle screw instrumentation for lumbar degenerative diseases were prospectively enrolled. The visual analog scale (VAS) for ATP was recorded, and a pain map was drawn daily from the operation day to postoperative day 7 in all patients. We also prospectively collected the preoperative and intraoperative data to identify the risk factors associated with ATP. Radiologically, the total cross-sectional area (CSA), retraction length, and retraction CSA of PMM were measured from the preoperative T2-weighted axial magnetic resonance imaging scans at the L4–5 intervertebral disc level. The patients were stratified into two groups based on the experience of ATP with a VAS score of ≥ 7 at any time point. Additionally, a binary logistic regression analysis was performed to identify the associated factors. Results: The current prospective study included 92 patients (31 men, 61 women) with a mean age of 70.4 years (range, 56–86 years), who underwent OLIF at our institution. The left-side approach was used in 73 patients (79.3%), while 19 (20.7%) underwent a right-side approach. Sixty-five of the total patients (70.6%) experienced approach-side ATP to any extent during postoperative 0–7 days following OLIF. The mean pain VAS (4.4 ± 2.1) and the prevalence (57.6%) were highest at postoperative 2 days. On postoperative day 7, there were 19 patients (20.7%) who complained of residual ATP with a mean VAS of 2.6 ± 1.8. In the multivariate analysis, the PMM retraction length was significantly associated with ATP of VAS ≥ 7 (adjusted odds ratio, 2.316; p = 0.044). Conclusions In this study, we prospectively collected and analyzed the ATP and associated factors following OLIF and identified the PMM retraction length as a potential independent risk factor for severe ATP in the immediate postoperative period following OLIF.

Methods: Multimodality IONM data, including somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP), were reviewed in 64 patients who underwent three-column spinal surgery from 2011 to 2015. Surgical procedures included posterior vertebral column resection, pedicle subtraction osteotomy, total en bloc spondylectomy, piecemeal spondylectomy, and corpectomy with laminectomy (n=27) in three cervical, 34 thoracic, and 31 lumbar procedures. Results: Significant IONM signal changes occurred in 11 of 64 (17.1%) patients. SSEP and MEP were changed in 11 patients. Postoperative neurologic deterioration occurred in 54.5% (6 of 11) of the patients, and two of them were permanent. There was no postoperative neurologic deterioration in patients without significant signal change. Suspected causes of IONM data changes are as follows: adhesion/tethering, translation, contusion, and perfusion. Conclusions Based on the results of this study, to enhance neurologic safety in three-column spinal surgery, surgeons should pay attention to protect the spinal cord from mechanical insult, especially when the spinal column was totally destabilized during surgery, and not to compromise perfusion to the spinal cord in close cooperation with a neurologist and anesthesiologist.

Metastatic spinal tumors are common, and their rising incidence can be attributed to the expanding aging population and increased survival rates among cancer patients. The decision-making process in the treatment of spinal metastasis requires a multidisciplinary approach that includes medical and radiation oncology, surgery, and rehabilitation. Various decision-making systems have been proposed in the literature in order to estimate survival and suggest appropriate treatment options for patients experiencing spinal metastasis. However, recent advances in treatment modalities for spinal metastasis, such as stereotactic radiosurgery and minimally invasive surgical techniques, have reshaped clinical practices concerning patients with spinal metastasis, making a demand for further improvements on current decision-making systems. In this review, recent improvements in treatment modalities and the evolution of decision-making systems for metastatic spinal tumors are discussed.

Methods: We reviewed all spine surgery cases with IONM data treated at our department between January 2013 and May 2017. We found cases showing significant IONM signal improvements. We prospectively analyzed the neurological and clinical outcomes of these patients and compared outcomes pre- and postoperatively. Results: Among 317 cases with the IONM data, we found 29 cases that showed IONM signal improvement compared with baseline. There were 27 cases of compressive myelopathy: 22 had a degenerative cause at the cervical spine, and five, at the thoracic spine. There were two cases of huge neurogenic tumor each at the craniovertebral junction and at the lumbar spine. Both motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SSEPs) signals were improved in six cases, only the MEPs signal improved in 10, and only SSEP signal improved in 13 cases. All cases showed the IONM signal improvement consistently after the decompression procedure during surgery. All patients had a significant improvement in neurological function and subjective symptoms, and none had neurologic deterioration postoperatively. Conclusions Improvement of IONM signals during surgery may indicate that no unrecognized neural injury occurred during surgery and a favorable postoperative neurological outcome can be expected.