Objective: Advanced biportal endoscopic surgery techniques can be used to treat thoracic myelopathy secondary to ossification of the ligamentum flavum (OLF). This case series elaborates on a feasible biportal endoscopic technique for thoracic OLF removal and evaluates clinical and radiological outcomes.Methods: A biportal endoscopic posterior thoracic laminectomy was performed to remove the thoracic OLF. Surgical techniques have evolved from inside-out piecemeal removal methods to outside-in en bloc removal methods. Preoperative computed tomography was performed to analyze dural ossification and OLF types. Intraoperative videos were reviewed to observe dural ossification and to determine the surgical method. Neurological outcomes were assessed using the Japanese Orthopaedic Association (JOA) score.Results: Clinical symptoms and neurological function improved markedly after surgery (JOA score, preoperative: 12.6 ± 1.0, final follow-up: 15.6 ± 1.2). The mean operation time per segment was not short (106.6 ± 38 minutes). At early experience stages, inside-out piecemeal decompression was used and it caused intraoperative spinal cord injury. However, outside-in en bloc decompression technique did not induce neural complications. Postoperative segmental instability and correlated mechanical back pain were not observed.Conclusion: The biportal endoscopic posterior thoracic approach is an attractive surgical option to treat thoracic spondylotic myelopathy secondary to OLF. Piecemeal inside-out decompression can induce irreversible spinal cord injury, especially in the early experience stages. Outside-in decompression is more efficient and safer than inside-out pattern procedures by minimizing dural manipulation. Nonetheless, this technique is technically demanding and should only be performed in selected patients after acquiring abundant experience with endoscopic spine surgeries.

Despite current developments in bone substitute technology for spinal fusion, there is a lack of adequate materials for bone regeneration in clinical applications. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is commercially available, but a severe inflammatory response is a known side effect. Bone graft substitutes that enhance osteogenesis without adverse effects are needed. We developed a bioactive molecule-laden PLGA composite with multi-modulation for bone fusion. This bioresorbable composite scaffold was considered for bone tissue engineering. Among the main components, magnesium hydroxide (MH) aids in reduction of acute inflammation affecting disruption of new bone formation. Decellularized bone extracellular matrix (bECM) and demineralized bone matrix (DBM) composites were used for osteoconductive and osteoinductive activities. A bioactive molecule, polydeoxyribonucleotide (PDRN, PN), derived from trout was used for angiogenesis during bone regeneration. A nano-emulsion method that included Span 80 was used to fabricate bioactive PLGA-MH-bECM/DBM-PDRN (PME2/PN) composite to obtain a highly effective and safe scaffold. The synergistic effect provided by PME2/PN improved not only osteogenic and angiogenic gene expression for bone fusion but also improved immunosuppression and polarization of macrophages that were important for bone tissue repair, using a rat model of posterolateral spinal fusion (PLF). It thus had sufficient biocompatibility and bioactivity for spinal fusion.

The insertion of pedicle screws in the lateral position without a position change has been reported. We completed a retrospective comparison of the radiologic and clinical outcomes of 36 patients who underwent either single-position oblique lateral lumbar interbody fusion (SP-OLIF) using the O-arm (36 cases) or conventional OLIF (C-OLIF) using the C-arm (20 cases) for L2–5 single-level lumbar degenerative diseases. Radiological parameters were analyzed, including screw accuracy (Gertzbein-Robbins classification system; GRS), segmental instability, and fusion status. Screw misplacement was defined as a discrepancy of ≥2 mm. Clinical outcomes, including visual analog scale, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and postoperative complications, were assessed. The spinal fusion rate was not different between the SP-OLIF and C-OLIF groups one year after surgery (p = 0.536). The ODI score was lower (p = 0.015) in the SP-OLIF than the C-OLIF group. Physical (p = 0.000) and mental component summaries (p = 0.000) of the SF-36 were significantly higher in the SP-OLIF group. Overall complication rates, including revision, surgical site infection, ipsilateral weakness, and radicular pain/numbness, were not significantly different. SP-OLIF using the O-arm procedure is feasible, with acceptable accuracy, fusion rate, and complication rate. This may be an alternative to conventional two-stage operations.

Objective: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision.Methods: Patient data for ASD were sourced from the Korean spinal deformity database. PJK was defined a proximal junctional angle (PJA) of ≥ 20° at the final follow-up, or an increase in PJA of ≥ 10° compared to the preoperative values. Multivariable analysis was performed to identify independent variables. Subsequently, 5 machine learning models were created to predict individualized PJK risk post-ASD surgery. The most efficacious model was deployed as an online and interactive calculator.Results: From a pool of 201 patients, 49 (24.4%) exhibited PJK during the follow-up period. Through multivariable analysis, postoperative PJA, body mass index, and deformity type emerged as independent predictors for PJK. When testing machine learning models using study results and previously reported variables as hyperparameters, the random forest model exhibited the highest accuracy, reaching 83%, with an area under the receiver operating characteristics curve of 0.76. This model has been launched as a freely accessible tool at: (https://snuspine.shinyapps.io/PJKafterASD/).Conclusion: An online calculator, founded on the random forest model, has been developed to gauge the risk of PJK following ASD surgery. This may be a useful clinical tool for surgeons, allowing them to better predict PJK probabilities and refine subsequent therapeutic strategies.

Intervertebral disc (IVD) degeneration is a leading cause of chronic low back pain (LBP) that results in serious disability and significant economic burden. IVD degeneration alters the disc structure and spine biomechanics, resulting in subsequent structural changes throughout the spine. Currently, treatments of chronic LBP due to IVD degeneration include conservative treatments, such as pain medication and physiotherapy, and surgical treatments, such as removal of herniated disc without or with spinal fusion. However, none of these treatments can completely restore a degenerated disc and its function. Thus, although the exact pathogenesis of disc degeneration remains unclear, there are studies examining the effectiveness of biological approaches, such as growth factor injection, gene therapy, and cell transplantation, in promoting IVD regeneration. Furthermore, tissue engineering using a combination of cell transplantation and biomaterials has emerged as a promising new approach for repair or restoration of degenerated discs. The main purpose of this review was to provide an overview of the current status of tissue engineering applications for IVD regenerative therapy by performing literature searches using PubMed. Significant advances in tissue engineering have opened the door to a new generation of regenerative therapies for the treatment of chronic discogenic LBP.

To evaluate the relationship between comorbidities, medical cost, and surgical outcome in patients with lumbar spinal stenosis (LSS) and diabetes mellitus (DM). Data on patients with LSS (n = 14,298) were collected from the Korean National Health Insurance Service database from 2005 to 2007. After 8 years of follow-up, a “DM group” (n = 3,478) and a “non-DM group” (n = 10,820) were compared according to outcome measures. Cox proportional hazard regressions were performed to examine the relationship between DM, hypertension (HTN), cardiovascular disease (CVD), chronic kidney disease (CKD), cerebrovascular disease (CbVD), and surgery for LSS. The admission rate and medical cost as well asthe overall survival rate for those who underwent lumbar surgery were also assessed among patients with DM and LSS. Mortality was about 1.35 times higher in the DM group than in the non-DM group. Patients with DM and comorbidities including HTN (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.25–1.56; p<0.001), CVD (HR, 1.53; 95% CI, 1.36–1.73; p<0.001), CKD (HR, 3.18; 95% CI, 2.7–3.76; p<0.001), and CbVD (HR, 1.69; 95% CI, 1.49–1.91; p<0.001) showed an increased risk of mortality. The mean hospitalization time and average medical cost of patients with DM who underwent lumbar surgery were 60.8 days, and 7,127 USD, respectively. This was 31.3 days longer, and 6,207 USD higher, respectively, than those of patients with DM who underwent conservative treatment for LSS. Within the DM group, the survival rate of surgical management of LSS had a significant tendency for positive prognosis compared with those administered conservative treatment (p = 0.046). In patients with LSS, DM was associated both with poor prognosis (most significantly in those with CKD), and increased medical cost in those who underwent surgery. Nevertheless, surgical treatment for LSS in patients with DM was related to favorable prognosis compared with conservative treatment.