Three-dimensional morphological analysis of the thoracic pedicle and related radiographic factors in adolescent idiopathic scoliosis.

BACKGROUND: This study aimed to investigate the laterality of the pedicle morphology at the apical vertebra (AV) level and identify the radiographic factors associated with the laterality ratio of the pedicle morphology at the AV level in patients with adolescent idiopathic scoliosis (AIS). METHODS: Overall, 684 pedicles in 57 AIS patients aged 10-20 years, who underwent preoperative computed tomography (CT) and had Lenke type 1 or 2 with right convex main thoracic curves (MTC), were evaluated. Pedicle diameters of the MTC were assessed. We defined and compared the region containing two vertebrae adjacent to the AV (APEX±1) and the region containing two vertebrae adjacent to the neutral vertebra. We analyzed the pedicle diameter and laterality ratio of APEX±1 and performed multiple linear regression analysis to identify the radiographic factors associated with the laterality of the pedicle diameter. RESULTS: On the concave side of APEX±1, the pedicles of 15 patients (26.3%) did not accept a 4-mm-diameter pedicle screw (PS), even with 25% cortical bone width expansion. Laterality ratio differences in the pedicle diameters of the cortical bone width in APEX±1 were large in patients with more proximal AV level (p < 0.001) and smaller apical vertebral rotation (AVR) (p = 0.029). CONCLUSIONS: Preoperative planning to accurately select and insert the PS in AIS should be based on the anatomical limitations in APEX±1, AV level, and AVR degree. In APEX±1, the correlation between AVR and the laterality ratio of the pedicle diameter may be useful for pathoetiological interpretation of the AIS deformity.

Segmental coupling effects during correction of three-dimensional lumbar deformity using lateral lumbar interbody fusion.

PURPOSE: Lateral lumbar interbody fusion (LLIF) has been performed to correct spinal deformity associated with lumbar degenerative disease. Although its usefulness has been studied, there are no reports of quantitative evaluation in three dimensions. Our purpose is to quantitate 3D deformity of the patients with lumbar degenerative disease and correction of the deformity by LLIF using patient-specific 3D CT models. METHODS: We measured the disc height and 3D alignment of the lumbar spine in 28 patients with degenerative disease undergoing LLIF using patient-specific 3D CT models created preoperatively and 3 months after surgery. The 3D alignment was calculated as wedge, lordosis and axial rotation angles at each motion segment. The disc height and the rotational angles were compared between before and after LLIF. RESULTS: A strong positive correlation was found between the wedge angle and the axial rotation angles (r = 0.718, P < 0.001) in the patients with lumbar degenerative disease preoperatively. The wedge and axial rotation angles decreased after surgery (P < 0.001 and P < 0.001, respectively). A positive correlation was found between the corrected wedge angle and the corrected axial rotation angle (r = 0.46, P < 0.001). CONCLUSION: The present study demonstrated positive correlations between the wedge deformity and the axial rotational deformity in the patients with lumbar degenerative disease. The axial rotational deformity was simultaneously corrected with LLIF only by leveling the intervertebral wedge deformity via cage insertion without additional correction procedure. These slides can be retrieved under Electronic Supplementary Material.

Lumbar artery branches coursing vertically over the intervertebral discs of the lower lumbar spine: an anatomic study.

PURPOSE: Bleeding from the lumbar artery is a potential complication during the transpsoas approach to the lower lumbar intervertebral discs. In this anatomic study, the morphological relationships between the branches of the lumbar artery and the lower intervertebral disc were investigated to assess the risk of injury to the branches of the lumbar segmental arteries. METHODS: We studied 88 sites (86 lumbar arteries) at the third and fourth lumbar vertebrae bilaterally in 22 formalin-fixed cadavers. The branches of the lumbar artery coursing along the lateral sides of the lower intervertebral disc [muscular branch, anastomotic branch, and branch supplying the spinal nerve and plexus (BSNP)] and the iliolumbar artery running upward over the L4-5 disc were identified. Branches crossing the intervertebral discs vertically were evaluated. RESULTS: Muscular branches with a lumen structure longer than 2 cm coursed vertically over the middle third of the intervertebral disc in 3 of 88 sites (3.4 %). Anastomotic branches ran downward in 13 of 88 (14.8 %), and iliolumbar arteries ran upward on the posterior third of the lateral sides of the disc in 2 of 88 (2.3 %). BSNPs ran downward through the posterior third of the disc at 18 of 88 sites (20.5 %). Overall, the arterial branches coursed vertically over the posterior third of the lateral sides of the intervertebral discs in approximately 30 % of subjects. CONCLUSIONS: Lumbar artery branches coursed vertically over the middle third and the posterior third of the lateral sides of the intervertebral discs in approximately 3 and 30 % of subjects, respectively.

The incidence of and risk factors for developing atypical femoral fractures in Japan.

The long-term treatment with anti-resorptive drugs for osteoporotic patients is suggested to be associated with an increase in atypical femoral fractures (AFFs). However, their incidence, patient characteristics, and risk factors have not been fully elucidated especially in Asian countries. This retrospective observational cohort study found fourteen AFFs in ten patients (four bilateral fractures) among 2,238 hip and femoral shaft fractures treated in our associated hospitals between 2005 and 2010; this incidence (0.63%) was similar to Caucasians. Of the ten patients with AFFs, nine (90%) and six (60%) were using bisphosphonates (BPs) and glucocorticoids (GCs), respectively, compared to 14.3 and 8.6% for patients with typical femoral fractures who were using these agents. As comorbid conditions, five patients had collagen disease (CD) and two had diabetes. A fracture location-, age- and gender-matched (1:3) case-control study revealed that administration of BPs, GCs, and suffering from collagen disease (CD) were significant risk factors for developing AFFs [odds ratios 36.0 (95% confidence intervals 3.8-342.2), 13.0 (2.3-74.1) and 9.0 (1.6-50.3), respectively]. Interestingly, all of the patients with atypical subtrochanteric femoral fractures, defined as those within 5 cm of the lesser trochanter, were taking GCs due to CD, and the age of these patients (average of 54.8 years) was significantly younger than those with atypical diaphyseal femoral fractures (average of 77.2 years, p < 0.05). In conclusion, the incidence of AFFs in the Japanese population was similar to that of Caucasians, and taking BPs and GCs and suffering from CD were risk factors for developing AFFs.

Correlation of the total superoxide dismutase activity between joint fluid and synovium in end-stage knee osteoarthritis.

Recently, we found significantly reduced total superoxide dismutase (SOD) activity in the cartilage of patients with end-stage knee osteoarthritis (OA). In this study, we aimed to evaluate the SOD activity in serum, joint fluid, cartilage, and synovial membrane samples collected from 52 patients with end-stage knee OA who underwent total knee arthroplasty. The relationship between the total SOD activity in each tissue was evaluated using Spearman's rank correlation coefficient. The joint fluid total SOD activity was used as the objective variable, and its association with the serum, cartilage, and synovial total SOD activities was evaluated using multiple linear regression analysis. Univariate analysis revealed that joint fluid total SOD activity was positively correlated with synovial total SOD activity. Multiple linear regression analysis using joint fluid total SOD activity as the objective variable showed a positive association with synovial total SOD activity (ß = 0.493, adjusted R2 = 0.172, P < 0.01). In patients with end-stage knee OA, the state of the synovial total SOD activity is better reflected by the total SOD activity in the joint fluid than that in the cartilage. Joint fluid total SOD activity may serve as a biomarker for the treatment and prevention of synovitis.

Trans-Sacral Epiduroscopic Ho:YAG Laser Ablation of the Ligamentum Flavum in a Live Pig.

Introduction: For the aging population, surgery for lumbar spinal canal stenosis (LSCS) requires minimally invasive procedures. Recently, trans-sacral epiduroscopic laser decompression for lumbar disc herniation has been reported with good results. In this study, we devised a new method to perform trans-sacral epiduroscopic laser ablation of the ligamentum flavum (LF), known to be the major cause of LSCS. Using a live pig, this study aims to evaluate the efficacy, safety, and drawbacks of this procedure. Methods: Using an epiduroscope, we observed intra-spinal canal structures and then examined the feasibility and problems of a decompression procedure to ablate the LF using holmium:YAG (Ho:YAG) laser. The pig was observed for behavioral changes and neurological deficits after the procedure. Histological analysis was performed to evaluate the amount of tissue ablation and damage to surrounding tissues. Results: Although it was possible to partially ablate the LF using the Ho:YAG laser under epiduroscopy, it was difficult to maintain a clear field of view, and freely decompressing the target lesion has been a challenge. After the first two experiments, the pig neither showed abnormal behavior nor any signs of pain or paresis. However, in the third experiment, the pig died during the operation. On autopsy, no thermal or mechanical injury was noted around the ablated site, including the dura mater and nerve root. Histological analysis showed that the LF and lamina were deeply ablated as the laser power increased, and no damage was noted on surrounding tissues beyond a depth of 500 µm. Conclusions: Although Ho:YAG laser could ablate the ligamentum and bone tissues without causing damage to surrounding tissues, it was difficult to completely decompress the LF under epiduroscopy. This method is a potentially highly invasive procedure that requires caution in its clinical application and needs further improvement in terms of the instruments and techniques used.

Localization of the Lumbar Plexus in the Psoas Muscle: Considerations for Avoiding Lumbar Plexus Injury during the Transpsoas Approach.

INTRODUCTION: Transpsoas lumbar spine surgery is minimally invasive and has very good corrective effects. However, approach-side nerve complications delay post-operative rehabilitation. We anatomically investigated the localization of the lumbar plexus running in the psoas muscle. METHODS: We examined 27 formalin-fixed cadavers. The left-sided psoas muscle was extracted and cut parallel to the intervertebral disc at the L2/3, L3/4, and L4/5 disc levels. Using digitized photographs, we calculated the ratio of the distance from the front edge of the psoas muscle to the center of the lumbar plexus in the anteroposterior diameter of the psoas muscle (%). Then, we calculated the ratio of the distance from the lateral edge of the psoas muscle to the center of the lumbar plexus in the lateral diameter of the psoas muscle (%). RESULTS: The anterior-posterior lumbar plexus localization was 74.5 at L2/3, 74.7 at L3/4, and 81.2 at L4/5. There was a significant difference between L2/3 and L4/5 and between L3/4 and L4/5, but not between L2/3 and L3/4 (P=0.02, 0.01, and 0.94, respectively). The lateral and medial lumbar plexus localization was 85.4 at L2/3, 83.9 at L3/4, and 77.7 at L4/5. There was a significant difference between L2/3 and L4/5 and between L3/4 and L4/5, but not between L2/3 and L3/4 (P=0.01, 0.04, and 0.41, respectively). CONCLUSIONS: The lumbar plexus was localized in the posterior one-third and medial one-third of the psoas muscle and moved to a posterolateral location at L4/5. To avoid neuropathy, consider the psoas muscle's position relative to that of the intervertebral disc. It is essential to understand lumbar plexus localization in the psoas muscle when looking directly at this muscle to enter the pricking point or route with a lower risk of nerve damage.

Anterior Spinal Fusion Using Autologous Bone Grafting via the Lateral Approach with Posterior Short-Range Instrumentation for Lumbar Pyogenic Spondylitis with Vertebral Bone Destruction Enables Early Ambulation and Prevents Spinal Deformity.

INTRODUCTION: Pyogenic spondylitis of the lumbar spine markedly decreases the ability to perform activities of daily living and causes severe low back pain. The challenge is to improve low back pain and activities of daily living performance earlier and prevent post-infection sequelae, and conservative treatment with antibiotics is the mainstay of treatment. METHODS: In the present study, patients who were unable to walk following lumbar pyogenic spondylitis even in the subacute phase after successful infection control, showing bone defects expanding from endplate to vertebral body in CT, were treated with posterior percutaneous short-range instrumentation and anterior autogenous bone grafting (group S, n = 10) or with conservative treatment alone (group C, n = 10). Acute cases of absolute surgical indication with paralytic symptoms and mild cases who could walk by antibiotics administration were excluded. The two groups were compared regarding the post-treatment change in C-reactive protein level, duration of bed rest, and post-infection local spinal deformities (local scoliosis angle in the coronal plane and local kyphosis angle in the sagittal plane). RESULTS: Compared with group C, group S took a significantly shorter time for the C-reactive protein level to return to normal and required a significantly shorter duration of bed rest. Furthermore, surgery prevented the formation of kyphosis and scoliosis, while group C developed local kyphosis. CONCLUSIONS: The minimally invasive surgical method of posterior percutaneous short-range instrumentation and anterior autogenous bone grafting effectively enables early control of pain and maintenance of locomotive function and prevents spinal deformity in patients with lumbar pyogenic spondylitis in the subacute phase with advanced vertebral bone destruction.

Intraoperative ultrasound visualization of paravertebral anatomy in the retroperitoneal space during lateral lumbar spine surgery.

OBJECTIVE: Lumbar surgery via a lateral approach is a minimally invasive and highly useful procedure. However, care must be taken to avoid its potentially fatal complications of intestinal and vascular injuries. The object of this study was to evaluate the usefulness of intraoperative ultrasound in improving the safety of lateral lumbar spine surgery. METHODS: A transvaginal ultrasound probe was inserted into the operative field, and the intestinal tract, kidney, psoas muscle, and vertebral body were identified using B-mode ultrasound. The aorta, vena cava, common iliac vessels, and lumbar arteries and their associated branches were identified using the color Doppler mode. RESULTS: The study cohort comprised 100 patients who underwent lateral lumbar spine surgery, 92 via a left-sided approach. The intestinal tract and kidney lateral to the psoas muscle on the anatomical approach pathway were visualized in 36 and 26 patients, respectively. A detachment maneuver displaced the intestinal tract and kidneys in an anteroinferior direction, enabling confirmation of the absence of organ tissues above the psoas. In all patients, the major vessels anterior to the vertebral bodies and the lumbar arteries and associated branches in the psoas on the approach path were clearly visualized in the Doppler mode, and their orientation, location, and positional relationship with regard to the vertebral bodies, intervertebral discs, and psoas were determined. CONCLUSIONS: When approaching the lateral side of the lumbar spine in the retroperitoneal space, intraoperative ultrasound allows real-time identification of the blood vessels surrounding the lumbar spine, intestinal tract, and kidney in the approach path and improves the safety of surgery without increasing invasiveness.

Superoxide dismutase activity is significantly lower in end-stage osteoarthritic cartilage than non-osteoarthritic cartilage.

Recent studies have shown that superoxide dismutase 1 (SOD1), SOD2, and SOD3 are significantly decreased in human osteoarthritic cartilage. SOD activity is a marker that can be used to comprehensively evaluate the enzymatic capacities of SOD1, SOD2, and SOD3; however, the trend of SOD activity in end-stage osteoarthritic tissues remains unknown. In the present study, we found that SOD activity in end-stage osteoarthritic synovium of the knee was significantly lower than that in control synovium without the influence of age. The SOD activity was significantly lower in the end-stage knee osteoarthritic cartilage than in the control, but a weak negative correlation was observed between aging and SOD activity. However, SOD activity in end-stage hip osteoarthritic cartilage was significantly lower than that in control cartilage without the influence of aging. The relationship between osteoarthritis and SOD activity was stronger than the relationship between aging and SOD activity. These results indicate that direct regulation of SOD activity in joint tissues may lead to suppression of osteoarthritis progression.

The fracture sites of atypical femoral fractures are associated with the weight-bearing lower limb alignment.

PURPOSE: Atypical femoral fractures (AFFs) are stress-related fractures that are speculated to associate with long-term treatment with bisphosphonates for osteoporosis. A history of AFF is a high risk factor for the development of a subsequent AFF in the same location of the contralateral femur, suggesting that a patient's individual anatomical factor(s) are related to the fracture site of AFFs. In this study, we investigated the radiographs of fourteen AFFs (four bilateral fractures among ten patients) treated at six hospitals associated with our university between 2005 and 2010. The fracture site and standing femorotibial angle (FTA), which reflects the mechanical axis of the lower limb, were measured on weight-bearing lower limb radiographs. The fracture site and FTA of patients with typical femoral fractures (TFF) were compared to those of patients with AFFs. The correlations were examined using Spearman's rank correlation coefficients. The fracture locations in the femora were almost the same in the patients with bilateral AFFs. There was a positive correlation between the fracture site and the standing FTA in the patients with AFFs (r=0.82, 95% confidence interval; 0.49 to 0.94), indicating that the larger the standing FTA (varus alignment), the more distal the site of the fracture in the femur. The FTA of the patients with atypical diaphyseal femoral fracture were significantly larger compared to that of those with not only atypical subtrochanteric fractures but also TFFs. In conclusion, the fracture sites of AFFs are associated with the standing lower limb alignment, while those of TFFs are not.