Hiroto Makino

A 78-year-old woman developed groin and thigh pain, numbness, and hip flexion weakness. Imaging revealed cement leakage from an L4 screw into the psoas, compressing a lumbar plexus branch. Using a spinal robotic system (ExcelsiusGPS, Globus Medical, Inc., Audubon, PA), a minimally invasive approach enabled precise incision planning, safe psoas dissection, and en bloc cement removal. Symptoms resolved immediately. Symptomatic intrapsoas cement leakage causing radiculopathy is rare, and robotic guidance contributed to a safe, accurate procedure.

Background/Objectives. Correction of thoracolumbar/lumbar curvature in adolescent idiopathic scoliosis (AIS) patients with Lenke 1-2 B and C is still controversial, with regard to extension of the caudal side to the lowest instrumented vertebra (LIV) and method of correction. We assessed the association between change in thoracolumbar/lumbar curvature after surgery with counterrotate technique (CRT) and clinical factors in 45 thoracic AIS patients. Methods. Forty-five AIS patients (mean follow-up 5.1 y, age 15 y, Type B: 28, Type C: 17) were analyzed. Posterior spinal fusion was performed by the placing of segmental uni-planar screws, concave rod rotation, differential rod countering, and segmental CRT. Association between change in thoracolumbar/lumbar curvature after surgery with counter-rotate technique and clinical factors was analyzed in 45 thoracic AIS patients. Results. Mean main thoracic Cobb angle was 52°, and mean thoracolumbar/lumbar curvature Cobb angle was 35°. Postoperative thoracolumbar/lumbar Cobb was 10.1, and final follow-up was 8.2. Multi logistic regression analysis of change in thoracolumbar/lumbar Cobb after surgery was performed. Age (p < 0.05), Risser sign (p < 0.05), and postoperative thoracolumbar/lumbar Cobb (p < 0.0001) were significantly associated with a change in Cobb angle. Conclusions. Correction of thoracolumbar/lumbar curvature using CRT showed significant improvement of thoracolumbar/lumbar curvature, LIV tilting angle, and vertebral rotation. Postoperative thoracolumbar/lumbar Cobb angle (1st erect) was the most significant factor associated with deterioration of thoracolumbar/lumbar curvature after surgery. Subsequent rotational correction of thoracolumbar/lumbar curvature is likely to prevent the deterioration of thoracolumbar/lumbar Cobb after surgery.

The apical hypokyphosis of scoliotic patients is thought to lead to decreased lung capacity and cause shortness of breath. Additionally, concave rod curve reduction is a problem in the correction of apical hypokyphosis in posterior spinal fusion surgery in adolescent idiopathic scoliosis (AIS). We investigated the contributions of rod rotation (RR) with an outrigger device, followed by differential rod contouring (DRC) with the outrigger attached to the concave rod, designed to prevent concave rod curve-flattening. We analyzed and compared the results of segmental pedicle screw fixation without the outrigger in 41 AIS patients with thoracic curves (Lenke type I, 25; type II, 16) to those corrected using the outrigger in 36 patients (Lenke type I, 24; type II,12). The changes in the Cobb angle, apical kyphosis of five vertebrae, thoracic kyphosis (TK, T4–12), correction rate, correction angle of apical vertebral rotation, spinal penetration index (SPi), and rib hump index (RHi) before and after surgery were measured, and the contribution of the outrigger was analyzed. The mean scoliosis correction rates without and with the outrigger were 72.1° and 75.6°, respectively (p = 0.03). Kyphosis of the five apical vertebrae and TK were significantly greater in the surgery with the outrigger (p = 0.002). Significantly greater improvements in SPi and RHi were also noted in the surgery with the outrigger (p < 0.05). The use of concave RR and convex DRC with the outrigger appear to be advantageous for correcting apical hypokyphosis, followed by the subsequent formation of TK. As a result, breathing problems are less likely to occur during daily life because of improvements in SPi and RHi.

Objective: Using segmental dynamic and static factors, we aimed to elucidate the pathogenesis and relationship between ossification of the posterior longitudinal ligament (OPLL) and the severity of cervical myelopathy.Methods: Retrospective analysis of 163 OPLL patients' 815 segments. Imaging was used to evaluate each segmental space available for the spinal cord (SAC), OPLL diameter, type, bone space, K-line, the C2–7 Cobb angle, each segmental range of motion (ROM), and total ROM. Magnetic resonance imaging was used to evaluate spinal cord signal intensity. Patients were divided into the myelopathy group (M group) and the without myelopathy group (WM group).Results: Minimal SAC (p = 0.043), (C2–7) Cobb angle (p = 0.004), total ROM (p = 0.013), and local ROM (p = 0.022) were evaluated as an independent predictor of myelopathy in OPLL. Different from the previous report, the M group had a straighter whole cervical spine (p < 0.001) and poorer cervical mobility (p < 0.001) compared to the WM group. Total ROM was not always a risk factor for myelopathy, as its impact depended on SAC, when SAC > 5 mm, the incidence rate of myelopathy decreased with the increase of total ROM. Lower cervical spine (C5–6, C6–7) showing increased “Bridge-Formation,” along with spinal canal stenosis and segmental instability (C2–3, C3–4) in the upper cervical spine, could cause myelopathy in M group (p < 0.05).Conclusion: Cervical myelopathy is linked to the OPLL’s narrowest segment and its segmental motion. The hypermobility of the C2–3 and C3–4, contributes significantly to the development of myelopathy in OPLL.

Background Physiological and ideal spinal alignment is critical for efficient load transfer to support and maintain our body. However, in patients with adolescent idiopathic scoliosis (AIS), imbalanced load transfer occurs due to abnormal twisting and rotation of the spinal column. This study aimed to investigate the asymmetric stress overload and distribution on the facet joints of AIS patients using finite element (FE) analysis and surgical specimens. Methods FE models of the thoracic spine were created from a total of 13 female AIS patients (Lenke type 1, n = 4: Lenke type 2 n = 5; Lenke type 3, n = 4). A load of 200 N on the T3 vertebra and 30 N each on the bilateral superior articular processes were applied in the vertical direction to quantify the contact force on the facet joints from T3 to T11. In addition, morphological and histological analyses were performed on the inferior articular processes taken during surgery. Results Contact forces of the facet joint progressively increased from the mid to lower thoracic spine of the concave side, reaching a maximum around the apex. More than 90% of the load was transmitted by the facet joints at the concave side, resulting in facet joint subchondral sclerosis and hypertrophy. Conclusions FE models revealed the asymmetric stress overload and distribution on the facet joints of AIS. The asymmetric load transmission could be responsible for degeneration, such as hypertrophy and subchondral sclerosis of the facet joint of AIS.

Ossification of the posterior longitudinal ligament (OPLL) is considered a multifactorial condition characterized by ectopic new bone formation in the spinal ligament. Recently, its connections with inflammation as well as sacroiliac (SI) joint ankylosis have been discussed. Nevertheless, whether inflammation, spinal ligament ossification, and SI joint changes are linked in OPLL has never been investigated. In this study, whole-spinal computed tomography and serum high-sensitive C-reactive protein (hs-CRP) levels were obtained in 162 patients with cervical OPLL. Ossification lesions were categorized as plateau and hill shapes. Accordingly, patients were divided into plateau-shaped (51 males and 33 females; mean age: 67.7 years) and hill-shaped (50 males and 28 females; mean age: 67.2 years) groups. SI joint changes were classified into four types and three subtypes, as previously described. Interactions among ossification shapes, hs-CRP levels, and morphological changes in the SI joint were investigated. The plateau shape was more common in the vertebral segments (59.5%), compared to the hill shape, which was predominant in the intervertebral regions (65.4%). Serum hs-CRP levels in the plateau-shaped group (0.11 ± 0.10 mg/dL) were significantly higher than those in the hill-shaped group (0.07 ± 0.08 mg/dL). SI joint intra-articular fusion was the main finding in the plateau-shaped group and showed significantly higher hs-CRP levels compared to the anterior para-articular bridging, which more frequently occurred in the hill-shaped group. Our findings suggested a possible inflammation mechanism that might contribute to the new bone formation in OPLL, particularly the plateau shape.

The role of the ligamentum flavum (LF) in the pathogenesis of adolescent idiopathic scoliosis (AIS) is not well understood. Using magnetic resonance imaging (MRI), we investigated the degrees of LF hypertrophy in 18 patients without scoliosis and on the convex and concave sides of the apex of the curvature in 22 patients with AIS. Next, gene expression was compared among neutral vertebral LF and LF on the convex and concave sides of the apex of the curvature in patients with AIS. Histological and microarray analyses of the LF were compared among neutral vertebrae (control) and the LF on the apex of the curvatures. The mean area of LF in the without scoliosis, apical concave, and convex with scoliosis groups was 10.5, 13.5, and 20.3 mm², respectively. There were significant differences among the three groups (p < 0.05). Histological analysis showed that the ratio of fibers (Collagen/Elastic) was significantly increased on the convex side compared to the concave side (p < 0.05). Microarray analysis showed that ERC2 and MAFB showed significantly increased gene expression on the convex side compared with those of the concave side and the neutral vertebral LF cells. These genes were significantly associated with increased expression of collagen by LF cells (p < 0.05). LF hypertrophy was identified in scoliosis patients, and the convex side was significantly more hypertrophic than that of the concave side. ERC2 and MAFB genes were associated with LF hypertrophy in patients with AIS. These phenomena are likely to be associated with the progression of scoliosis.

Intervertebral disc (IVD) diseases are common spinal disorders that cause neck or back pain in the presence or absence of an underlying neurological disorder. IVD diseases develop on the basis of degeneration, and there are no established treatments for degeneration. IVD diseases may therefore represent a candidate for the application of regenerative medicine, potentially employing normal human dermal fibroblasts (NHDFs) induced to differentiate into nucleus pulposus (NP) cells. Here, we used a three-dimensional culture system to demonstrate that ectopic expression of MYC, KLF4, NOTO, SOX5, SOX6, and SOX9 in NHDFs generated NP-like cells, detected using Safranin-O staining. Quantitative PCR, microarray analysis, and fluorescence-activated cell sorting revealed that the induced NP cells exhibited a fully differentiated phenotype. These findings may significantly contribute to the development of effective strategies for treating IVD diseases.

Background: Severe postsurgical pain in posterior spinal fusion is common. Multimodality analgesia, including opioid-based patient-controlled analgesia (PCA), is commonly used, but opioid-related adverse events such as nausea and vomiting are sometimes a problem. We used a ropivacaine-epinephrine-dexamethasone mixture given as one-time local bilateral submyofascial injections at the operated levels added to conventional multimodality analgesia including PCA for postoperative pain control in one group of patients to confirm whether administration of this mixture reduced postoperative pain and opioid use status post posterior spinal fusion. Methods: We retrospectively reviewed 67 consecutive patients who had undergone posterior fusion surgery for adolescent idiopathic scoliosis (AIS), 35 of whom were treated with conventional analgesia that consisted mainly of PCA (control group) and 32 of whom were treated with one-time submyofascial injections of a ropivacaine-epinephrine-dexamethasone mixture (submyofascial injection group) added to conventional multimodality analgesia. We compared postsurgical pain levels and the amount of opioid use over the first 48 h after surgery, as well as physical activity levels and adverse events 2 weeks after surgery. Results: Postsurgical pain quantified by a numeric rating scale (1–10) in the submyofascial injection group was significantly lower than that in the control group. The amount of fentanyl use was significantly less in the submyofascial injection group at 24 h, 48 h, and all subsequent periods after surgery. In addition, Walking Recovery Time (WRT) defined as the number of days until the first event of ambulation was significantly less in the submyofascial injection group (3.3 d vs 4.1 d, P = 0.0007)). Laxative use was significantly less in the submyofascial injection group (0.3 times vs 1.3 times, P = 0.02). Conclusions: One-time submyofascial injections at the operated levels with a ropivacaine-epinephrine-dexamethasone mixture after spinal fusion surgery reduced pain, opioid consumption, and opioid-related adverse events. This technique can contribute significantly to postoperative analgesia.