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.

Novel Predictive Scoring System for Bone Union Rate After Conservative Management of Lumbar Spondylolysis.

STUDY DESIGN: A single-center retrospective cohort study. OBJECTIVES: To develop a predictive scoring system for bone union after conservative treatment of lumbar spondylolysis and assess its internal validity. SUMMARY OF BACKGROUND DATA: Lumbar spondylolysis, a common stress fracture in young athletes, is typically treated conservatively. Predicting bone union rates remains a challenge. METHODS: This study included patients aged ≤18 years with lumbar spondylolysis undergoing conservative treatment. A multivariable logistic regression analysis was used to develop a scoring system containing six factors: sex, age, lesion level, main side stage of the lesion, contralateral side stage of the lesion, and spina bifida occulta. The predictive scoring system was internally validated from the receiver operating characteristic (ROC) curve using bootstrap methods. RESULTS: The final analysis included 301 patients with 416 lesions, with an overall bone union rate of 80%. On multivariable analysis, the main and contralateral stages were identified as factors associated with bone union. The predictive scoring system was developed from the main side stage score (prelysis, early=0, progressive stage=1) and the contralateral side stage score (none=0, prelysis, early, progressive stage=1, terminal stage=3). The area under the curve was 0.855 (95% confidence interval: 0.811-0.896) for the ROC curve, showing good internal validity. The predicted bone union rates were generally consistent with the actual rates. CONCLUSIONS: A simple predictive scoring system was developed for bone union after conservative treatment of lumbar spondylolysis, based on the stage of the lesion on the main and contralateral sides. The predicted bone union rate was approximately 90% for a total score of 0-1 and ≤30% for a score of 3-4. This system demonstrated good internal validity, suggesting its potential as a useful tool in clinical decision making for the management of spondylolysis.

A case of recurrent erythema induratum of Bazin in a patient with myelodysplastic syndrome.

We describe a case of erythema induratum of Bazin (EIB) that presented recurrently on the extremities during treatment with anti-tuberculosis medications. The anti-tuberculosis medications were effective, so they were continued despite the occurrence of the EIB lesions, and those lesions disappeared 5 months after first appearing. EIB is currently considered a multifactorial disorder with many different causes, with tuberculosis being an example, and it is thought to be a hypersensitive immune response to Mycobacterium tuberculosis. The clinical manifestations may fluctuate depending on the immune response of the host. Our patient was affected with myelodysplastic syndrome, and we believe that this was a major factor that interfered with a normal immune response. This case illustrates the importance of providing intensive anti-tuberculosis treatment from the start, and in cases where EIB co-presents, to continue this treatment until the end, in order to prevent relapse.

Early Recurrence of Thoracic Ossification of the Ligamentum Flavum After Posterior Decompression Surgery: A Case Report.

Thoracic ossification of the ligamentum flavum (OLF) is known to result in spinal canal stenosis and myelopathy. It is typically treated through decompressive laminectomy and resection of the ossified ligament, which is known to improve neurological deficits. However, the recurrence of OLF post-surgery remains a relatively undocumented and complex issue. The present report describes the case of a 58-year-old male patient who had obesity (BMI 34), diabetes mellitus, and Basedow's disease. The patient presented with bilateral lower limb paresthesia and associated gait impairment, resulting in an urgent hospital admission. Imaging diagnostics identified extensive thoracic ossification of the posterior longitudinal ligament and OLF, both of which resulted in significant spinal cord compression. He underwent posterior decompression with instrumented fusion from T1 to T9 and additional laminectomy and OLF resection at T10/11. Despite an initial improvement in the postoperative period, the patient developed an epidural hematoma one week following surgery, causing significant paralysis of the lower limbs. This complication was promptly addressed with hematoma removal surgery. Six months after the initial procedure, his walking function improved significantly, but eight months after surgery, he experienced a sudden regression in motor functions due to the recurrence of OLF at T10/11, necessitating an additional posterior instrumented fusion surgery. Subsequent to the additional surgical procedure, the patient experienced an amelioration in paralysis, enabling him to ambulate with the aid of a cane. The recurrence of thoracic OLF after decompression surgery is a significant concern, especially in cases where decompression without instrumented fusion is performed. When determining the surgical procedure for thoracic OLF in cases with extensive ossification of the spinal ligaments, it is crucial to consider the degree of spontaneous fusion and mobility of the spinal segments, as demonstrated in the present case. The concentration of mechanical stress due to fusion at adjacent segments and intervertebral mobility at the thoracolumbar junction may increase the risk of OLF recurrence and should be carefully assessed preoperatively, even though posterior decompression surgery is typically considered a sufficient option for thoracic OLF.

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial.

BACKGROUND AND OBJECTIVE: Opening wedge high tibial osteotomy (OWHTO) influences the knee extensor mechanism, the range of passive motion of knee extension and persistent quadriceps, and anterior knee pain and weakness. Rehabilitation should focus on quadriceps strength and improving joint mobility. The single-joint hybrid assistive limb device (HAL-SJ) is a wearable exoskeleton cyborg. In this study, we investigated the feasibility and safety of HAL-SJ training after the early postoperative period following OWHTO and whether the use of this device can improve functional outcomes, including knee muscle extensor strength and knee extension range of motion without knee pain. METHODS: Patients who had been diagnosed with knee osteoarthritis and had undergone OWHTO were assessed for eligibility in this prospective trial conducted at our institution between June 2015 and November 2020. The participants were split into two groups, i.e., 10 patients in the hybrid assistive limb (HAL) group and eight patients in the control group. We initiated HAL-SJ therapy on postoperative day 8 and continued it until the patient's discharge. During the hospitalization period, patients engaged in HAL-SJ-assisted knee extension exercises. This exercise routine encompassed five sets, each comprising 10 repetitions, and was conducted twice a week. We conducted assessments aimed at detecting any potential adverse events that could be linked to HAL training. Assessment of the knee extension angle via the visual analog scale (VAS) and strength assessments using a hand-held dynamometer (HHD) were conducted. To compare clinical outcomes before and after OWHTO, knee extension angle, the VAS, HHD, Japanese Orthopaedics Association (JOA) score, and the Japanese Knee Osteoarthritis Measure (JKOM) were assessed at four distinct time points. RESULTS: No adverse events were observed during the study. The assessment of clinical outcomes before and after OWHTO demonstrated a gradual improvement in outcomes. CONCLUSION: The single-joint hybrid assistive limb device in patients who underwent OWHTO appears to be potentially safe. It contributed to enhanced muscle activity efficiency by reducing knee pain and improving knee extension angles in the early postoperative phase.

Potential of Titanium Pins Coated with Fibroblast Growth Factor-2-Calcium Phosphate Composite Layers to Reduce the Risk of Impaired Bone-Pin Interface Strength in the External Fixation of Distal Radius Fractures.

Background: The risk of impaired bone-pin interface strength in titanium (Ti) pins coated with fibroblast growth factor (FGF)-calcium phosphate (CP) composite layers is yet to be evaluated in a clinical study. This retrospective study used Weibull plot analysis to evaluate bone-pin interface strength in Ti pins coated with FGF-CP layers for external distal radius fracture fixation. Methods: The distal radial fractures were treated with external fixation. The FGF-CP group comprised five patients (all women, aged 70.4 ± 5.9 (range: 62-77) years), and the uncoated pin group comprised ten patients (eight women and two men, aged 64.4 ± 11.7 (range: 43-83) years). The pins were removed after six weeks. The insertion and extraction peak torques were measured. The extraction peak torque was evaluated using Weibull plot analysis. Results: We compared the extraction torque of the two groups at or below 506 Nmm for a fair comparison using Weibull plot analysis. The Weibull plots were linear for both the FGF-CP and uncoated pin groups. The slope of the regression line was significantly higher in the FGF-CP group (1.7343) than in the uncoated pin group (1.5670) (p = 0.011). The intercept of the regression line was significantly lower in the FGF-CP group (-9.847) than in the uncoated pin group (-8.708) (p = 0.002). Thus, the two regression lines significantly differed. Conclusions: Ti pins coated with FGF-CP layers exhibit the potential to reduce the risk of impaired bone-pin interface strength in the external fixation of distal radius fractures.

Factors Associated with Discharge Destination in Patients with Bone Metastases.

Background and Objectives: The discharge destination of patients with advanced cancer correlates with their quality of life. Patients with bone metastases often undergo lifestyle changes owing to pain and activity limitations. However, there are few reports on factors related to the discharge destination of patients with bone metastases. This study aimed to elucidate the factors associated with the discharge destination of patients with bone metastases. Methods: This study included 278 patients diagnosed with bone metastases who were admitted to the University of Tsukuba Hospital between April 2015 and March 2020. This study examined discharge destination, occurrence of skeletal-related events (SREs), primary lesions, locations of bone metastases, functional ambulation categories (FAC), age, and length of hospital stay. A binomial logistic regression analysis was conducted to compare the home and non-home discharge groups. Results: Of the 278 patients, 142 were discharged to home, 89 were discharged to somewhere other than home (non-home), and 47 died. The discharge destination was associated with spinal cord compression (SCC) (odds ratio [OR] 3.37, 95% confidence interval [CI] 1.35-8.43), hypercalcemia (OR 6.84, 95% CI 1.09-42.76), and FAC at admission (OR 0.45, 95% CI 0.35-0.58). The admission FAC cut-off value for discharge to home was determined to be 1.5 (area under the curve [AUC] 0.79, sensitivity 77.5%, specificity 68.5%). Conclusions: Factors associated with discharge destination were identified. The walking ability required for discharge to home was FAC 1.5, meaning that the patient needed one person to assist in preventing falls when walking on level ground. A cut-off value for FAC on admission for predicting outcomes was identified, suggesting the importance of gait ability assessment on admission.

Pedicle screw insertion into infected vertebrae reduces operative time and range of fixation in minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis: a multicenter retrospective cohort study.

BACKGROUND: Minimally invasive posterior fixation surgery for pyogenic spondylitis is known to reduce invasiveness and complication rates; however, the outcomes of concomitant insertion of pedicle screws (PS) into the infected vertebrae via the posterior approach are undetermined. This study aimed to assess the safety and efficacy of PS insertion into infected vertebrae in minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis. METHODS: This multicenter retrospective cohort study included 70 patients undergoing minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis across nine institutions. Patients were categorized into insertion and skip groups based on PS insertion into infected vertebrae, and surgical data and postoperative outcomes, particularly unplanned reoperations due to complications, were compared. RESULTS: The mean age of the 70 patients was 72.8 years. The insertion group (n = 36) had shorter operative times (146 versus 195 min, p = 0.032) and a reduced range of fixation (5.4 versus 6.9 vertebrae, p = 0.0009) compared to the skip group (n = 34). Unplanned reoperations occurred in 24% (n = 17) due to surgical site infections (SSI) or implant failure; the incidence was comparable between the groups. Poor infection control necessitating additional anterior surgery was reported in four patients in the skip group. CONCLUSIONS: PS insertion into infected vertebrae during minimally invasive posterior fixation reduces the operative time and range of fixation without increasing the occurrence of unplanned reoperations due to SSI or implant failure. Judicious PS insertion in patients with minimal bone destruction in thoracolumbar pyogenic spondylitis can minimize surgical invasiveness.

Safety and feasibility of in-hospital autonomous transportation using a driverless mobility for patients with musculoskeletal disorders: preliminary clinical study to achieve mobility as a service in medical care.

BACKGROUND: Recent advancements in and the proliferation of autonomous mobility technology, such as intelligent wheelchairs, have made it possible to provide mobility services for patients with reduced mobility due to musculoskeletal disorders. In the present study, we conducted a preliminary clinical study to assess the safety and feasibility of in-hospital autonomous transportation using a driverless mobility (wheelchair) for patients with musculoskeletal disorders. METHODS: From January to February 2022, 51 patients with musculoskeletal disorders exhibiting gait disturbance who presented to our institution were included in the present study. Driverless mobility rides were conducted over a straight-line distance of 100 m from the orthopaedic outpatient reception to the payment counter after the outpatient consultation. We assessed the quality of life using an EQ-5D-5 L index and pain using a VAS score before riding the mobility to investigate the patient's condition. After the ride, a questionnaire survey was conducted to assess patient satisfaction on a 5-point scale. In addition, adverse events during the mobility ride were investigated. RESULTS: Overall satisfaction levels showed that 44 out of 51 (86%) patients rated the level as 3 or higher. There were no significant differences in the level of satisfaction based on the cause of disorders or EQ-5D-5 L Index. Among 19 patients who rated the level of satisfaction as 2-3, the ratio of postoperative patients and those with pain tended to be higher (p < 0.05). While 26 of 51 (51%) patients reported moments of feeling unsafe during the mobility ride, no actual adverse events, such as collisions, were observed. CONCLUSIONS: An in-hospital autonomous transportation service using a driverless mobility for patients with musculoskeletal disorders demonstrated high satisfaction levels and was safe with no severe adverse events observed. The expansion of autonomous mobility deployment is expected to achieve mobility as a service in medical care.

The association between variations in the number of thoracic and lumbar vertebrae and rib morphology in adolescent idiopathic scoliosis.

PURPOSE: Preoperative counting of thoracic and lumbar vertebrae is crucial in adolescent idiopathic scoliosis (AIS) due to reported anatomical variations and potential surgical site misidentification. This study investigated characteristics associated with the vertebral number variations AIS, particularly focusing on rib morphology. METHODS: Based on three-dimensional computed tomography, patients were categorized into the non-variant number group, comprising individuals with 12 thoracic and 5 lumbar vertebrae, and the variant number group, comprising individuals with different numbers of vertebrae. Additionally, the most caudal rib morphology was classified as normal, unilateral, or hypoplastic. RESULTS: A total of 359 patients were included in our study (41 males, 318 females, age: 16.3 ± 3.1 years), with 44 patients (12.3%) assigned to the variant number group. Logistic regression analysis identified unilateral ribs (odds ratio [OR]: 10.50) and lumbosacral transitional vertebrae (LSTV) (OR 6.49) as significant risk factors associated with variations. Further analysis revealed hypoplastic ribs as a significant risk factor associated with LSTV (OR: 4.58). 8 CONCLUSION: Our study suggests that abnormal rib morphology may be associated with vertebral number variations. Close attention to rib morphology is, therefore, warranted in cases with atypical vertebral numbers. Accordingly, to ensure surgical safety and accuracy, spine surgeons must communicate these variations to the surgical team, standardize nomenclature for describing them, and intraoperatively verify fusion levels with them.

Developing a Novel Prosthetic Hand with Wireless Wearable Sensor Technology Based on User Perspectives: A Pilot Study.

Myoelectric hands are beneficial tools in the daily activities of people with upper-limb deficiencies. Because traditional myoelectric hands rely on detecting muscle activity in residual limbs, they are not suitable for individuals with short stumps or paralyzed limbs. Therefore, we developed a novel electric prosthetic hand that functions without myoelectricity, utilizing wearable wireless sensor technology for control. As a preliminary evaluation, our prototype hand with wireless button sensors was compared with a conventional myoelectric hand (Ottobock). Ten healthy therapists were enrolled in this study. The hands were fixed to their forearms, myoelectric hand muscle activity sensors were attached to the wrist extensor and flexor muscles, and wireless button sensors for the prostheses were attached to each user's trunk. Clinical evaluations were performed using the Simple Test for Evaluating Hand Function and the Action Research Arm Test. The fatigue degree was evaluated using the modified Borg scale before and after the tests. While no statistically significant differences were observed between the two hands across the tests, the change in the Borg scale was notably smaller for our prosthetic hand (p = 0.045). Compared with the Ottobock hand, the proposed hand prosthesis has potential for widespread applications in people with upper-limb deficiencies.

Bone mineral density changes around the stem correlate with stress changes after total hip arthroplasty: A study using thermoelastic stress analysis.

Purpose: Thermoelastic stress analysis (TSA) was used to evaluate stress changes over the entire surface of a specimen. This study aimed to assess the relationship between femoral stress distribution, analysed using TSA and changes in bone mineral density (BMD) after total hip arthroplasty (THA). Methods: Stress changes in the simulated bone before and after taper-wedge stem insertion were measured using the TSA. Stress changes were compared with BMD changes around the stem 1 year after surgery in a THA patient (58 hips) with the same taper-wedge stem. Subsequently, we compared the correlation between stress changes and BMD changes. Results: TSA revealed significant stress changes before and after stem insertion, with prominent alterations in the proximal medial region. The BMD changes at 1 year post-THA exhibited a 15%-25% decrease in the proximal zones, while Zones 2-6 showed a -6% to 3% change. Notably, a strong positive correlation (0.886) was found between the stress change rate and BMD change rate. Conclusions: This study demonstrated a high correlation between femoral stress distribution assessed using TSA and subsequent BMD changes after THA. The TSA method offers the potential to predict stress distribution and BMD alterations postsurgery, aiding in implant development and clinical assessment. Combining TSA with finite element analysis could provide even more detailed insights into stress distribution. Level of Evidence: Case series (with or without comparison).

A patient and public involvement study to explore patient perspectives on the efficacy of treatments for pain and numbness derived from ossification of posterior longitudinal ligament of the spine.

BACKGROUND: Chronic pain and numbness are common complaints in patients with ossification of the posterior longitudinal ligament of the spine (OPLL). However, it is unclear whether the current treatments are effective in patients with OPLL in terms of improving pain and numbness. METHODS: A cross-sectional survey of patients with OPLL was conducted to determine patient satisfaction with surgery and drug therapy for pain and numbness, and its association with health-related quality of life. The survey was conducted by a patient association and its members, and anonymized data were analyzed by physicians. Comparisons between groups were made using T-tests or Kruskal-Wallis and Steel-Dwass tests, chi-square tests, and Fisher's exact tests. RESULTS: Data from 121 patients with OPLL (age 69 ± 11 years, 69 males; 43 females; and 7 unknown) who completed a mailed questionnaire were analyzed. Of the 93 patients with a history of surgery for OPLL, 24% and 18% reported much improvement in pain and numbness, respectively. After surgery, 42% and 48% reported some improvement, and 34% and 34% reported no improvement, respectively. Patients whose numbness did not improve with surgery had a significantly poorer health-related quality of life than those who did. Of the 78 patients who received medication, only 2% reported "much improvement," 64% reported "some improvement," and 31% reported "no improvement at all." Compared to patients with OPLL only in the cervical spine, those with diffuse-type OPLL showed poorer improvement in numbness after surgery and poorer quality of life. CONCLUSIONS: The majority of patients with OPLL belonging to the association were unsatisfied with surgery and pharmacotherapy in terms of pain and numbness improvement, indicating that there is an unmet medical need for more effective treatment for chronic pain and numbness in patients with OPLL.

Varus knee osteoarthritis with ankle osteoarthritis demonstrates greater hindfoot inversion and larger ankle inversion loading during gait following total knee arthroplasty compared to varus knee osteoarthritis alone.

PURPOSE: Although patients with varus knee osteoarthritis (KOA) and concurrent ankle osteoarthritis (AOA) may experience increased ankle joint pain after total knee arthroplasty (TKA), the underlying mechanism remains unclear. This study aimed to investigate the effects of concurrent AOA on ankle and hindfoot alignment, frontal plane ankle and hindfoot biomechanics during gait following TKA and the clinical outcomes. METHODS: Twenty-four patients with varus KOA who underwent TKA were included in this retrospective cohort study. Patients were categorized into two groups: with and without AOA. Radiographic evaluations of lower-limb, ankle and hindfoot alignment, and knee and ankle clinical outcomes were conducted preoperatively and 6 months postoperatively. In addition, gait analyses were performed to investigate knee, ankle and hindfoot kinematics and kinetics. Each data was compared between patients with and without AOA. RESULTS: Concomitant AOA was found in eight ankles. The AOA group exhibited greater postoperative hindfoot varus and increased postoperative ankle pain than the non-AOA group. Gait analysis showed no significant differences in knee varus alignment or tibial tilt after TKA between the groups. However, the AOA group demonstrated significantly greater hindfoot inversion and larger ankle inversion loading. CONCLUSION: One third of patients who underwent TKA had concurrent AOA associated with hindfoot varus. Despite achieving proper coronal knee alignment postoperatively, these patients experienced greater hindfoot and ankle joint inversion load during gait. Surgeons should consider the inability to evert the hindfoot and the possibility of increased ankle joint pain when planning and performing TKA. LEVEL OF EVIDENCE: Level III.

Use of Unidirectional Porous ß-Tricalcium Phosphate in the Tibial Tunnel for Anterior Cruciate Ligament Reconstruction: A Case Series.

Bone defects in the tibial tunnel for anterior cruciate ligament (ACL) reconstruction can cause adverse events. The unidirectional porous tricalcium ß-phosphate (UDPTCP) has the potential to be used as a filling substitute for bone defects. In this case series, we present the first nine cases in which UDPTCP was used as a bone substitute in the tibial tunnel during ACL reconstruction. The patients comprised six males and three females, with an average age of 32 years (range: 16-50 years). A cylindrical UDPTCP measuring 10 x 20 mm was molded to fit the tibial tunnel and then implanted. At the one-year postoperative follow-up, none of the patients demonstrated any complications, and bone remodeling was observed on radiographs. Therefore, UDPTCP may provide a safe and reliable filling substitute for the tibial tunnel in ACL reconstruction.

Factors Influencing Optimal Bracing Compliance in Adolescent Idiopathic Scoliosis: A Single Center Prospective Cohort Study.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify factors contributing to optimal bracing compliance in adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Poor brace compliance is a key factor affecting brace treatment success in AIS. Predictive factors influencing optimal brace compliance to achieve brace treatment success remain unknown. MATERIALS AND METHODS: This study included AIS patients, aged 10-15, with a Cobb angle of 20-40 degrees. Demographics data, radiographic assessments, and patient-reported outcomes (including the SRS-22r patient questionnaire) were collected. Brace compliance was monitored using in-brace thermometers, defining optimal bracing time as more than 18 hours/day. Multivariable logistic regression analysis was employed to identify predictors of optimal bracing time from the demographic and patient- reported outcomes score before bracing. RESULTS: Among 122 patients, 59.0% achieved optimal bracing time by six months. The achieved group indicated higher scores in satisfaction domain before bracing (3.3±0.7 vs. 3.1±0.6; P=0.034). Multivariable logistic regression analysis demonstrated that Satisfaction domain before bracing was an independent factor associated with achievement of the optimal bracing time (OR 1.97 [95%CI 1.00 - 3.89], P=0.049). The model with bracing at 1-month follow-up also demonstrated the bracing at 1-month was a significant factor (OR 1.52 [95%CI 1.30 - 1.79], P<0.001). CONCLUSION: Optimal bracing compliance in AIS is significantly influenced by pre-bracing satisfaction and brace compliance at earlier time point. These findings highlight the need to address psychological factors and early compliance in AIS bracing treatment. SRS-22r can be useful to identify the need for psychological support.

Retroperitoneal abscess associated with closed pelvic ring fracture diagnosed by fine free air on initial trauma pan computed tomography scan.

The patient was a 49-year-old male. He had a closed fracture of the pelvic ring that was treated successfully by avoiding anterior pelvic ring stabilization because of the presence of microscopic free air in the retroperitoneal space behind the pubic bone on initial whole-body trauma computed tomography scan. For his pelvic ring injury, transiliac rod and screw fixation was performed without the need for a pubic symphysis plate by developing the retroperitoneal space. His retroperitoneal abscess was treated by minimally invasive treatment of retroperitoneal abscess with computed tomography-guided percutaneous drainage. At 2 years postoperatively, there was no fever or elevated inflammatory response suspicious of retroperitoneal abscess recurrence. In this case, the presence of microscopic free air influenced the choice of treatment. Even in closed pelvic ring fractures, the presence of free air should be carefully considered when reading images.

Measurement of Postoperative Apical Vertebral Rotation Using Radiographic Images in Adolescent Idiopathic Scoliosis-Quantitative Evaluation Using Inverse Trigonometric Functions.

Introduction: Conventional methods for analyzing vertebral rotation are limited to postoperative patients who underwent posterior fusion. A previous methodology calculated vertebral rotation using inverse trigonometric functions based on the length of the pedicle screw (PS). Accordingly, this study evaluates rotational deformity in patients with postoperative adolescent idiopathic scoliosis (AIS) using inverse trigonometric functions. Methods: This retrospective single-center study includes patients with AIS who underwent posterior fusion surgery. Postoperative radiography and computed tomography (CT) scans were retrospectively evaluated. The magnification ratio was calculated using the rod diameter (δ=lateral/frontal rod diameter), and the visible screw lengths were measured using radiographs. The rotation angle was calculated using the apex of the main curve and the lower instrumented vertebra (LIV) (rotation angle=tan-1 (lateral PS length/(δ×frontal PS length))) immediately following the surgery as well as two and five years postoperatively. The correlation between the direct CT measurement and postoperative rotation angle progression was investigated. The crankshaft phenomenon (CSP) and distal adding-on (DAO) were evaluated as postoperative deformities. CSP was defined as a 5° increase in rotation angle. Results: Seventy-eight patients (age: 15.3±2.0 years, eight boys and seventy girls) were included. The rotation angle was strongly correlated with CT rotation measurements (r=0.87). The mean rotation angle at the apex and LIV did not change within five years postoperatively (mean: 0.5±3.6° and 0.4±3.4°, respectively). CSP and DAO were observed in 6.4% and 3.8% of patients, respectively. Conclusions: The inverse trigonometric method is useful to quantitatively evaluate the postoperative rotation angle and identify CSP.

The Optimal Patient Position on the Surgical Table for Lateral Lumbar Interbody Fusion in Adult Spinal Deformity Using Three-Dimensional Computed Tomography: A Retrospective Study.

Introduction: Lateral lumbar interbody fusion (LLIF) techniques have been extensively used in adult spinal deformity surgery. Preoperative knowledge of the optimal position of the patient on the surgical table is essential for a safe procedure. Therefore, this study aims to determine the optimal angle for positioning the patient on the surgical table during LLIF using three-dimensional computed tomography (3DCT). Methods: Data from 59 patients (2 males, 57 females, mean age 66.3±8.6 years) with adult spinal deformities treated by performing corrective spinal surgery were included in this observational retrospective study. Simulated fluoroscopic images were obtained using 3DCT images rotated from the reference position with the spinous process of S1 as the midline to the position with the spinous process in the center of the bilateral pedicle of T12-L5. The rotation angle of each vertebra was measured and defined as the optimal rotation angle (ORA). The angle that bisected the angle between the maximum and minimum ORA was defined as the optimal mean angle of the maximum and minimum ORA (OMA) and considered the optimal angle for the patient's position on the surgical table, as this position could minimize the rotation angle of the surgical table during surgery. A multiple regression analysis was performed to predict OMA. Results: Multiple regression analysis revealed the following equation: OMA=1.959+(0.238×lumbar coronal Cobb angle)+(-0.208×sagittal vertical axis). Conclusions: When the patient is placed on the surgical table by rotating them at the OMA, the rotation of the surgical table can be reduced, ensuring a safe and efficient surgical procedure.

Characteristics of Lumbar Spondylolysis in Adolescent Baseball Players: Relationship between the Laterality of Lumbar Spondylolysis and the Throwing or Batting Side.

STUDY DESIGN: A retrospective, cross-sectional study was conducted to analyze the implications of asymmetric baseball movements on the incidence of spondylolysis. PURPOSE: This study aimed to evaluate the relationship between asymmetric movements and the laterality of spondylolysis. OVERVIEW OF LITERATURE: Baseball, characterized by its asymmetric throwing and batting, may disproportionately stress one side. Lumbar spondylolysis is a frequent cause of lower back pain in young athletes, particularly those involved in activities with consistent unilateral rotations such as baseball. However, whether a link exists between the laterality in spondylolysis and the dominant throwing/ batting side or whether disparities exist between pitchers and fielders remains unclear. METHODS: The study included 85 players. Participants were divided into two groups: pitchers and fielders. The association between the laterality of spondylolysis and the throwing/batting side in the overall cohort and between the two groups was evaluated. RESULTS: Among pitchers, 16 lesions appeared on the throwing side and 32 on the nonthrowing side (p =0.029). For fielders, no notable difference was observed between the two sides (p =0.363). Furthermore, batting preference did not influence the laterality of spondylolysis in either group. CONCLUSIONS: Adolescent baseball players, particularly pitchers, exhibited a higher incidence of lumbar spondylolysis on the side opposite their throwing arm. The findings of this study highlight the significant effect of asymmetrical sporting activities on the development of spondylolysis, to which pitchers are particularly susceptible.