A case of invasive mucinous adenocarcinoma presenting with massive bronchorrhea.

An 80-year-old non-smoking woman was admitted to hospital due to persistent sputum production and dyspnea. She developed respiratory failure, and chest imaging revealed multifocal consolidation and cavities. Her respiratory status did not respond to antimicrobial treatment and progressively worsened, with massive sputum production of approximately 1 L per day, and she died 19 days after admission. The patient was diagnosed with invasive mucinous adenocarcinoma based on a postmortem needle biopsy of the lung. Clinicians should consider invasive mucinous adenocarcinoma in the differential diagnosis of patients who present with massive bronchorrhea and diffuse pulmonary cavity abnormalities.

Appropriate pelvic obliquity measurement method in Lenke type 5C adolescent idiopathic scoliosis: a preliminary study.

Background: Although pelvic obliquity (PO) is a risk factor for postoperative coronal decompensation in corrective surgery in adolescent idiopathic scoliosis (AIS), especially Lenke 5C, methods of measuring PO are controversial. This study aimed to establish an appropriate measurement method using multiplanar reconstructed computed tomography (MPR-CT) images instead of standing posteroanterior (PA) whole-spine radiographs to evaluate PO in patients with Lenke 5C AIS. Methods: This study was a retrospective cross-sectional study. Twenty-five patients who underwent corrective surgery for AIS in Osaka University Hospital from August 2014 to February 2023 were included. Cobb angle, L5 tilt, C7 plumb line to center sacral vertebral line (C7PL-CSVL), and leg length discrepancy (LLD) were measured on standing PA whole-spine radiographs preoperatively. Sacral obliquity (SO), the slope of the upper endplate of S1, and iliac obliquity (IO), the tilt of the line connecting the iliac crests, were measured on standing PA whole-spine radiographs and MPR-CT (SO/IO-X-ray, SO/IO-CT, respectively). S1 angle and S2 angle were measured on CT. Results: The mean age of the patients was 18.7±3.9 years and all of them were females. SO-X-ray and SO-CT were larger than IO-X-ray and IO-CT, respectively. SO-X-ray was highly correlated with SO-CT (r=0.838, P<0.001). L5 tilt had higher correlation with SO-CT (r=0.884, P<0.001) than with SO-X-ray (r=0.726, P=0.001) and IO-CT (r=0.550, P=0.22). L5 tilt was correlated poorly with IO-X-ray (r=0.104, P=0.69). The S1 angle was 4.5±3.5° meanwhile the S2 angle was 1.2±2.1°, the sacral deformity was mainly due to the S1 vertebral wedging. Conclusions: Given the asymmetric sacral morphology, SO is more appropriate pelvic parameter than IO to represent the sacral tilt of Lenke 5C AIS, especially when measured using CT images to overcome the poor visibility on PA whole-spine radiographs.

Multimodal Deep Learning-based Radiomics Approach for Predicting Surgical Outcomes in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: A retrospective analysis. OBJECTIVE: This research sought to develop a predictive model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using deep learning and machine learning (ML) techniques. SUMMARY OF BACKGROUND DATA: Determining surgical outcomes assists surgeons in communicating prognosis to patients and setting their expectations. Deep learning and ML are computational models that identify patterns from large datasets and make predictions. METHODS: Of the 482 patients, 288 patients were included in the analysis. A minimal clinically important difference (MCID) was defined as gain in Japanese Orthopaedic Association (JOA) score of 2.5 points or more. The predictive model for MCID achievement at 1 year post-surgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed via LightGBM and deep learning with RadImagenet. RESULTS: The median preoperative JOA score was 11.0 (IQR: 9.0-12.0), which significantly improved to 14.0 (IQR: 12.0-15.0) at 1 year after surgery (P < 0.001, Wilcoxon signed-rank test). The average improvement rate of the JOA score was 44.7%, and 60.1% of patients achieved the MCID. Our model exhibited an area under the receiver operating characteristic curve of 0.81 and the accuracy of 71.9% in predicting MCID at 1 year. Preoperative JOA score and certain preoperative imaging features were identified as the most significant factors in the predictive models. CONCLUSION: A predictive ML and deep learning model for surgical outcomes in OPLL patients is feasible, suggesting promising applications in spinal surgery. LEVEL OF EVIDENCE: 4.

Platythorax increases residual volume/total lung capacity in idiopathic pleuroparenchymal fibroelastosis.

Platythorax significantly contributes to the increase in residual volume/total lung capacity ratio in patients with idiopathic pleuroparenchymal fibroelastosis https://bit.ly/3uZ0rmP.

An 88-Year-Old Woman With Pneumothorax and Black Pleural Effusion.

CASE PRESENTATION: An 88-year-old woman was admitted to our hospital with the sudden onset of dyspnea after eating. The patient had undergone nephrectomy for a left renal tumor 24 years previously. The patient had been prescribed ferrous citrate for iron-deficiency anemia. She complained of appetite loss a few days before admission but had no abdominal pain. CT scan showed no abnormalities in the lungs but a mass in the liver.

Automated entry of paper-based patient-reported outcomes: Applying deep learning to the Japanese orthopaedic association back pain evaluation questionnaire.

BACKGROUND: Health-related patient-reported outcomes (HR-PROs) are crucial for assessing the quality of life among individuals experiencing low back pain. However, manual data entry from paper forms, while convenient for patients, imposes a considerable tallying burden on collectors. In this study, we developed a deep learning (DL) model capable of automatically reading these paper forms. METHODS: We employed the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, a globally recognized assessment tool for low back pain. The questionnaire comprised 25 low back pain-related multiple-choice questions and three pain-related visual analog scales (VASs). We collected 1305 forms from an academic medical center as the training set, and 483 forms from a community medical center as the test set. The performance of our DL model for multiple-choice questions was evaluated using accuracy as a categorical classification task. The performance for VASs was evaluated using the correlation coefficient and absolute error as regression tasks. RESULT: In external validation, the mean accuracy of the categorical questions was 0.997. When outputs for categorical questions with low probability (threshold: 0.9996) were excluded, the accuracy reached 1.000 for the remaining 65 % of questions. Regarding the VASs, the average of the correlation coefficients was 0.989, with the mean absolute error being 0.25. CONCLUSION: Our DL model demonstrated remarkable accuracy and correlation coefficients when automatic reading paper-based HR-PROs during external validation.

Development of patient-reported outcome for adult spinal deformity: validation study.

Adult spinal deformity (ASD) is a complex condition that combines scoliosis, kyphosis, pain, and postoperative range of motion limitation. The lack of a scale that can successfully capture this complex condition is a clinical challenge. We aimed to develop a disease-specific scale for ASD. The study included 106 patients (mean age; 68 years, 89 women) with ASD. We selected 29 questions that could be useful in assessing ASD and asked the patients to answer them. The factor analysis found two factors: the main symptom and the collateral symptom. The main symptom consisted of 10 questions and assessed activity of daily living (ADL), pain, and appearance. The collateral symptom consisted of five questions to assess ADL due to range of motion limitation. Cronbach's alpha was 0.90 and 0.84, respectively. The Spearman's correlation coefficient between the change of main symptom and satisfaction was 0.48 (p < 0.001). The effect size of Cohen's d for comparison between preoperative and postoperative scores was 1.09 in the main symptom and 0.65 in the collateral symptom. In conclusion, we have developed a validated disease-specific scale for ASD that can simultaneously evaluate the benefits and limitations of ASD surgery with enough responsiveness in clinical practice.

Long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living, life expectancy, and the risk factors for postoperative mortality.

BACKGROUND: Because of the high incidence of major perioperative adverse events, spine surgery in dialysis patients should be recommended carefully after consideration of its risks and benefits. However, the benefits of spine surgery in dialysis patients remain unclear because of the lack of long-term outcomes. The purpose of this study is to elucidate the long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living (ADLs), life expectancy, and risk factors for postoperative mortality. METHODS: Data for 65 dialysis patients who underwent spine surgery at our institution and were followed up for a mean duration of 6.2 years were retrospectively reviewed. ADLs, number of surgeries, and survival times were recorded. The postoperative survival rate was calculated using the Kaplan-Meier method, and risk factors for postoperative mortality were investigated using a generalized Wilcoxon test and multivariate Cox proportional-hazards model. RESULTS: Compared with preoperative ADLs, ADLs significantly improved at discharge after surgery and at the final follow-up. However, 16 of the 65 patients (24.6%) underwent multiple surgeries, and 34 (52.3%) died during the follow-up period. Kaplan-Meier analysis revealed that the survival rate after spine surgery was 95.4% at 1 year, 86.2% at 3 years, 69.6% at 5 years, 59.7% at 7 years, and 28.7% at 10 years, and the overall median survival time was 99 months. Multivariate Cox regression analysis showed that a dialysis period of ≥10 years was a significant risk factor. CONCLUSIONS: Spine surgery in dialysis patients improved and maintained ADLs in the long term and did not shorten life expectancy. However, dialysis patients undergoing spine surgery require multiple surgeries more frequently, and a dialysis period of ≥10 years is a significant risk factor for postoperative mortality.

Risk Factor Analysis of Surgery-related Complications in Primary Thoracic Spine Surgery for Degenerative Diseases and Characteristics of the Patients Also Undergoing Surgery on the Cervical and/or Lumbar Spine.

STUDY DESIGN: A retrospective cohort study using prospectively collected data. OBJECTIVE: This study primarily aimed to investigate the risk factors for surgery-related complications in primary thoracic spine surgery for degenerative diseases using a surgeon-maintained database. The secondary purpose was to elucidate the characteristics of surgically treated thoracic myelopathy that also required cervical and/or lumbar spine surgery in the study period. SUMMARY OF BACKGROUND DATA: Few studies reported surgical complications and the feature of tandem spinal stenosis in thoracic myelopathy in detail because of their rarity. MATERIALS AND METHODS: This study included 840 thoracic myelopathy patients undergoing primary surgery for degenerative diseases from 2012 to 2021, investigating the effects of diseases, surgical procedures, and patient demographics on postoperative neurological deterioration, dural tear, dural leakage, surgical-site infection, and postoperative hematoma. In thoracic myelopathy patients who were surgically treated and also undergoing cervical and/or lumbar surgery, we investigated the proportion, the effects of diseases, and the order and intervals between surgeries. RESULTS: Multivariate logistic regression revealed that significant risk factors ( P <0.05) for postoperative neurological deterioration were intervertebral disk herniation [odds ratio (OR): 4.59, 95% confidence interval (CI): 1.32-16.0) and degenerative spondylolisthesis (OR: 11.1, 95% CI: 2.15-57.5). Ossification of the ligamentum flavum (OR: 4.12, 95% CI: 1.92-8.86), anterior spinal fusion (OR: 41.2, 95% CI: 4.70-361), and circumferential decompression via a posterior approach (OR: 30.5, 95% CI: 2.27-410) were risk factors for dural tear. In thoracic myelopathy patients surgically treated, 37.0% also underwent degenerative cervical and/or lumbar surgery. CONCLUSIONS: Pathologies involving anterior decompression and instability increased the risk of postoperative neurological deterioration. The risk of dural tear was increased when dura mater adhesions were likely to be directly operated upon. It should be recognized that a relatively high proportion (37.0%) of surgically treated thoracic myelopathy patients also underwent cervical and/or lumbar surgery.

Bimodal artificial intelligence using TabNet for differentiating spinal cord tumors-Integration of patient background information and images.

We proposed a bimodal artificial intelligence that integrates patient information with images to diagnose spinal cord tumors. Our model combines TabNet, a state-of-the-art deep learning model for tabular data for patient information, and a convolutional neural network for images. As training data, we collected 259 spinal tumor patients (158 for schwannoma and 101 for meningioma). We compared the performance of the image-only unimodal model, table-only unimodal model, bimodal model using a gradient-boosting decision tree, and bimodal model using TabNet. Our proposed bimodal model using TabNet performed best (area under the receiver-operating characteristic curve [AUROC]: 0.91) in the training data and significantly outperformed the physicians' performance. In the external validation using 62 cases from the other two facilities, our bimodal model showed an AUROC of 0.92, proving the robustness of the model. The bimodal analysis using TabNet was effective for differentiating spinal tumors.

Which treatment provides the best neurological outcomes in acute spinal cord injury?

Initial treatment of traumatic spinal cord injury remains as controversial in 2023 as it was in the early 19th century, when Sir Astley Cooper and Sir Charles Bell debated the merits or otherwise of surgery to relieve cord compression. There has been a lack of high-class evidence for early surgery, despite which expeditious intervention has become the surgical norm. This evidence deficit has been progressively addressed in the last decade and more modern statistical methods have been used to clarify some of the issues, which is demonstrated by the results of the SCI-POEM trial. However, there has never been a properly conducted trial of surgery versus active conservative care. As a result, it is still not known whether early surgery or active physiological management of the unstable injured spinal cord offers the better chance for recovery. Surgeons who care for patients with traumatic spinal cord injuries in the acute setting should be aware of the arguments on all sides of the debate, a summary of which this annotation presents.

Review of Basic Research about Ossification of the Spinal Ligaments Focusing on Animal Models.

Ossification of the posterior longitudinal ligament (OPLL) is a heterotopic ossification that may cause spinal cord compression. With the recent development of computed tomography (CT) imaging, it is known that patients with OPLL often have complications related to ossification of other spinal ligaments, and OPLL is now considered part of ossification of the spinal ligaments (OSL). OSL is known to be a multifactorial disease with associated genetic and environmental factors, but its pathophysiology has not been clearly elucidated. To elucidate the pathophysiology of OSL and develop novel therapeutic strategies, clinically relevant and validated animal models are needed. In this review, we focus on animal models that have been reported to date and discuss their pathophysiology and clinical relevance. The purpose of this review is to summarize the usefulness and problems of existing animal models and to help further the development of basic research on OSL.

Development of a system to assess the two- and three-dimensional bone mineral density of the lumbar vertebrae from clinical quantitative CT images.

This study developed a system to quantify the lumbar spine's bone mineral density (BMD) in two and three dimensions for osteoporosis screening using quantitative CT images. Measuring the two-dimensional BMD could reproduce the BMD measurement performed in dual-energy X-ray absorptiometry, and an accurate diagnosis of osteoporosis was possible. PURPOSE: To date, the assessment of bone mineral density (BMD) using CT images has been made in three dimensions, leading to errors in detecting osteoporosis based on the two-dimensional assessments of BMD using dual-energy X-ray absorptiometry (DXA-BMD). Herein, we aimed to develop a system that measures two- and three-dimensional lumbar BMD from quantitative CT images and validated the accuracy of the system in diagnosing osteoporosis with regard to the DXA classification. METHODS: Fifty-nine pairs of spinal CT and DXA images were analyzed. First, the three-dimensional BMD was measured at the axial slice of the L1 vertebra on CT images (L1-vBMD). Then, the L1-L4 vertebrae were segmented from the CT images to measure the three-dimensional BMD at the trabecular region of the L1-L4 vertebral bodies (CT-vBMD). Lastly, the segmented vertebrae were projected onto the coronal plane to measure the two-dimensional BMD (CT-aBMD). Each parameter was correlated with DXA-BMD, and the receiver operating characteristic (ROC) curve to diagnose osteoporosis was assessed. RESULTS: The correlation coefficients of DXA-BMD with L1-vBMD, CT-vBMD, and CT-aBMD were 0.364, 0.456, and 0.911, respectively (all p < 0.01). In the ROC curve analysis to diagnose osteoporosis, the area under the curve for CT-aBMD (0.941) was significantly higher than those for L1-vBMD (0.582) and CT-vBMD (0.657) (both p < 0.01). CONCLUSION: Compared with L1-vBMD and CT-vBMD, CT-aBMD could accurately predict DXA-BMD and detect patients with osteoporosis. Given that our method can quantify BMD in both two and three dimensions, it could be used to screen for osteoporosis from quantitative CT images.

Preoperative Risk Factors Affecting Outcome in Surgically Treated Pyogenic Spondylodiscitis.

STUDY DESIGN: Retrospective study. OBJECTIVE: The primary aim of this study was to investigate the predictors of severe complications in patients following surgery for pyogenic spondylodiscitis (PS) using a surgeon-maintained database. The secondary aim was to investigate the predictors of early recovery. METHODS: We introduced a surgeon-maintained database of prospectively collected multicenter data that mainly focused on perioperative complications in 2012. Our surgeon-maintained database allows the retrospective collection of detailed data. We analyzed 143 patients who underwent surgery for PS from the 19,056 patients in the prospective surgeon-maintained database at 27 affiliated institutions between 2013 and 2017. Data relating to preoperative patient factors, infection factors, surgical factors, and pre- and postoperative blood tests was retrospectively collected. We performed multivariate regression analysis to evaluate the predictors of postoperative severe complications and early recovery in patients with PS. RESULTS: High updated Charlson comorbidity index (uCCI), chronic pulmonary disease, diabetes, Gram-negative bacteria, pyogenic osteoarthritis, high preoperative white blood cell count, and low preoperative platelet count were significantly associated with severe complications in patients undergoing surgery for PS. A high uCCI was the sole independent negative predictor on early recovery. CONCLUSION: Careful perioperative management is necessary if surgery is performed on patients who are at a high risk of life-threatening events.

Risk factors for insufficient reduction after short-segment posterior fixation for thoracolumbar burst fractures: Does the interval from injury onset to surgery affect reduction of fractured vertebrae?

BACKGROUND: Many surgeons have encountered patients who could not immediately undergo surgery to treat spinal fractures because they had associated injuries and/or because a complete diagnosis was delayed. For such patients, practitioners might assume that delays could mean that the eventual reduction would be insufficient. However, no report covered risk factors for insufficient reduction of fractured vertebra including duration from injury onset to surgery. The purpose of this study is to investigate the risk factors for insufficient reduction after short-segment fixation of thoracolumbar burst fractures. METHODS: Our multicenter study included 253 patients who sustained a single thoracolumbar burst fracture and underwent short-segment fixation. We measured the local vertebral body angle (VBA) on roentgenograms, before and after surgery, and then calculated the reduction angle and reduction rate of the fractured vertebra by using the following formula: [Formula: see text] A multiple logistical regression analysis was performed to identify risk factors for insufficient reduction. The factors that we evaluated were age, gender, affected spine level, time elapsed from injury to surgery, inclusion of vertebroplasty with surgery, load-sharing score (LSS), AO classification (type A or B), preoperative VBA, and the ratio of canal compromise before surgery. RESULTS: There were 140 male and 113 female patients, with an average age of 43 years, and the mean time elapsed between injury and surgery was 3.8 days. The mean reduction angle was 12°, and the mean reduction rate was 76%. The mean LSS was 6.4 points. Multiple linear regression analysis revealed that a higher LSS, a larger preoperative VBA, a younger age, and being female disposed patients to having a larger reduction angle and reduction rate. The time elapsed from injury to surgery had no relation to the quality of fracture reduction in the acute period. CONCLUSIONS: Our findings indicate that if there is no neurologic deficit, we might not need to hurry surgical reduction of fractured vertebrae in the acute phase.

Development of artificial intelligence for automated measurement of cervical lordosis on lateral radiographs.

Cervical sagittal alignment is an essential parameter for the evaluation of spine disorders. Manual measurement is time-consuming and burdensome to measurers. Artificial intelligence (AI) in the form of convolutional neural networks has begun to be used to measure x-rays. This study aimed to develop AI for automated measurement of lordosis on lateral cervical x-rays. We included 4546 cervical x-rays from 1674 patients. For all x-rays, the caudal endplates of C2 and C7 were labeled based on consensus among well-experienced spine surgeons, the data for which were used as ground truth. This ground truth was split into training data and test data, and the AI model learned the training data. The absolute error of the AI measurements relative to the ground truth for 4546 x-rays was determined by fivefold cross-validation. Additionally, the absolute error of AI measurements was compared with the error of other 2 surgeons' measurements on 415 radiographs of 168 randomly selected patients. In fivefold cross-validation, the absolute error of the AI model was 3.3° in the average and 2.2° in the median. For comparison of other surgeons, the mean absolute error for measurement of 168 patients was 3.1° ± 3.4° for the AI model, 3.9° ± 3.4° for Surgeon 1, and 3.8° ± 4.7° for Surgeon 2. The AI model had a significantly smaller error than Surgeon 1 and Surgeon 2 (P = 0.002 and 0.036). This algorithm is available at ( https://ykszk.github.io/c2c7demo/ ). The AI model measured cervical spine alignment with better accuracy than surgeons. AI can assist in routine medical care and can be helpful in research that measures large numbers of images. However, because of the large errors in rare cases such as highly deformed ones, AI may, in principle, be limited to assisting humans.

Effects of rhBMP-2-loaded hydroxyapatite granules/beta-tricalcium phosphate hydrogel (HA/ß-TCP/hydrogel) composite on a rat model of caudal intervertebral fusion.

The effects and inflammation-related side effects of bone morphogenetic protein (BMP)-2 on posterior lumbar interbody fusion are controversial. One of the potential causes for the inconsistent results is the uncontrolled release of BMP-2 from the collagen carrier. Therefore, BMP delivery systems that support effective bone regeneration while attenuating the side effects are strongly sought for. We developed NOVOSIS putty (NP), a novel composite material of hydroxyapatite (HA), beta-tricalcium phosphate (ß-TCP)/hydrogel, and BMP-2, which can sustainably release BMP-2 over 2 weeks. This study was aimed at comparing the effects and side effects of NP and collagen sponge (CS) containing BMP-2 using a rat caudal intervertebral fusion model. The fusion rates of NP with low and high doses of BMP-2 were significantly higher than those of an iliac bone (IB) graft, but those of CS with low and high doses of BMP-2 were not different from those of the IB graft. Furthermore, the incidences of ectopic bone formation and soft tissue swelling were significantly lower in the NP group than in the CS group. The HA/ß-TCP/hydrogel carrier enabled superior bone induction with low-dose BMP-2 and decreased the incidence of side effects caused by high-dose BMP-2 vis-à-vis the collagen carrier.

Postoperative improvement in leg length discrepancy in adolescent idiopathic scoliosis differs between right and left legs.

Background: In adolescent idiopathic scoliosis (AIS) patients, leg length discrepancies (LLDs) often occur to compensate for scoliosis. However, there have been no reports on the LLD changes after corrective surgery for AIS. This study aimed to clarify the difference of LLD changes after corrective surgery for AIS by classifying LLD based on the shortened side. Methods: We analyzed preoperative and postoperative radiographs of 94 consecutive AIS patients who underwent posterior corrective surgery between 2012 and 2018. The patients enrolled were divided into three groups according to the presence of preoperative LLD of more than 5 mm and the LLD side: the left leg shortened group (L group), the non-LLD group (N group), and the right leg shortened group (R group). The three groups were compared with regard to age, sex, Lenke classification, Risser grade, fused levels, and radiographic parameters before surgery and at 6-month follow-up (thoracic Cobb angle, lumbar Cobb angle, L4 tilt, coronal balance, T1 tilt, and LLD). Results: The L, N, and R groups included 23 (24%), 60 (64%), and 11 patients (12%), respectively. The demographics and radiographic parameters were not significantly different among the groups except for preoperative L4 tilt. In the L group only, the LLD decreased from 7.9 ± 2.2 mm to 5.7 ± 3.7 mm (p = 0.002) after surgery. In contrast, the LLD in the N and R groups did not change significantly. Conclusions: The postoperative improvement of LLD in AIS patients differed between the left and right sides. Different pathologies may contribute to the LLD on the left and right sides.

Prostaglandin EP4 Selective Agonist AKDS001 Enhances New Bone Formation by Minimodeling in a Rat Heterotopic Xenograft Model of Human Bone.

To enhance bone regeneration, the use of bone morphogenetic protein (BMP)-2 is an attractive option. Unfortunately, the dose-dependent side effects prevent its widespread use. Therefore, a novel osteogenic agent using a different mechanism of action than BMP-2 is highly desirable. Previous reports demonstrated that prostaglandin E2 receptor 4 (EP4) agonists have potent osteogenic effects on non-human cells and are one of the potential alternatives for BMP-2. Here, we investigated the effects of an EP4 agonist (AKDS001) on human cells with a rat heterotopic xenograft model of human bone. Bone formation in the xenograft model was significantly enhanced by AKDS001 treatment. Histomorphometric analysis showed that the mode of bone formation by AKDS001 was minimodeling rather than remodeling. In cultured human mesenchymal stem cells, AKDS001 enhanced osteogenic differentiation and mineralization via the cAMP/PKA pathway. In cultured human preosteoclasts, AKDS001 suppressed bone resorption by inhibiting differentiation into mature osteoclasts. Thus, we conclude that AKDS001 can enhance bone formation in grafted autogenous bone by minimodeling while maintaining the volume of grafted bone. The combined use of an EP4 agonist and autogenous bone grafting may be a novel treatment option to enhance bone regeneration. However, we should be careful in interpreting the results because male xenografts were implanted in male rats in the present study. It remains to be seen whether females can benefit from the positive effects of AKDS001 MS by using female xenografts implanted in female rats in clinically relevant animal models.

Comparison of Short-Term Radiographical and Clinical Outcomes After Posterior Lumbar Interbody Fusion With a 3D Porous Titanium Alloy Cage and a Titanium-Coated PEEK Cage.

STUDY DESIGN: Clinical case series. OBJECTIVES: To compare the short-term (≤1 year) radiographical and clinical outcomes between posterior lumbar interbody fusion (PLIF) with a titanium-coated poly-ether-ether-ketone (TCP) cage and PLIF with a three-dimensional porous titanium alloy (PTA) cage. METHODS: Overall, 63 patients who had undergone 1- or 2-level PLIF since March 2015 were enrolled (median age, 71 years). The first 34 patients underwent PLIF with TCP cages (until June 2017) and the next 29 patients with PTA cages. Fusion status, vertebral endplate cyst formation (cyst sign: grade 0, none; grade 1, focal; and grade 2, diffuse), cage subsidence (grade 0, <1 mm; grade 1, 1-3 mm; and grade 2, >3 mm), and patient-reported quality of life (QOL) outcomes based on the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were compared at 6 months and 1 year postoperatively between the 2 cage groups. RESULTS: Cyst sign and cage subsidence grades were significantly lower in the PTA cage group than in the TCP cage group at 6 months postoperatively (cyst sign, p = 0.044; cage subsidence, p = 0.043). In contrast, the fusion rate and surgery effectiveness based on JOABPEQ at both 6 months and 1 year postoperatively were not different between the 2 groups. CONCLUSIONS: Patient-reported QOL outcomes were similar between the TCP and PTA cage groups until 1 year postoperatively. However, a higher incidence and severity of postoperative vertebral endplate cyst formation in patients with the TCP cage was a noteworthy radiographical finding.