STUDY DESIGN.A retrospective study.
OBJECTIVE.To assess the mechanisms and the independent risk factors associated with proximal junctional kyphosis (PJK) in patients treated surgically for adult ...spinal deformity with long fusions to the sacrum.
SUMMARY OF BACKGROUND DATA.The occurrence of PJK may be related to preoperative and postoperative sagittal parameters. The mechanisms and risk factors for PJK in adults are not well defined.
METHODS.Consecutive patients who underwent long instrumented fusion surgery (≥6 vertebrae) to the sacrum with a minimum of 2 years of follow-up were retrospectively studied. Risk factors included patient factors, surgical factors, and radiographical parameters such as thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis, pelvic tilt, and pelvic incidence.
RESULTS.Ninety consecutive patients (mean age, 64.5 yr) met inclusion criteria. Radiographical PJK occurred in 37 of the 90 (41%) patients with a mean follow-up of 2.9 years. The most common mechanism of PJK was fracture at the upper instrumented vertebra (UIV) in 19 (51%) patients. Twelve (13%) patients with PJK were treated surgically with proximal extension of the instrumented fusion. Preoperative TK more than 30°, preoperative proximal junctional angle more than 10°, change in LL more than 30°, and pelvic incidence more than 55° were identified as predictors associated with PJK. Achievement of ideal global sagittal realignment (sagittal vertical axis <50 mm, pelvic tilt <20°, and pelvic incidence-LL <±10°) protected against the development of PJK (19% vs. 45%). A multivariate regression analysis revealed changes in LL more than 30°, and preoperative TK more than 30° were the independent risk factors associated with PJK.
CONCLUSION.Fracture at the UIV was the most common mechanism for PJK. Change in LL more than 30° and pre-existing TK more than 30° were identified as independent risk factors. Optimal postoperative alignment of the spine protects against the development of PJK. A surgical strategy to minimize PJK may include preoperative planning for reconstructions with a goal of optimal postoperative alignment.Level of Evidence3
Background:
Sacral fatigue fractures are a rare injury but should be considered as a differential diagnosis for low back and buttock pain in young adults. Collective reports are limited, most of ...which have focused on long-distance runners.
Purpose:
To investigate the characteristics of sacral fatigue fractures in adolescents.
Study Design:
Case series; Level of evidence, 4.
Methods:
We analyzed patient background characteristics, physical examination and imaging findings, and treatment courses of those diagnosed with sacral fatigue fractures using magnetic resonance imaging.
Results:
Among 34 patients with sacral fatigue fractures, 15 and 19 were male and female patients, respectively, with an age range of 11 to 19 years (mean age, 15.0 years). Almost all patients were athletes, and 29 patients performed their sport ≥5 times a week. Long-distance runners were the most commonly affected, comprising 7 patients, and participants in other common sports such as baseball (6 patients), basketball (4 patients), and soccer (3 patients) were also affected. Physical examination revealed tension sign (Lasègue test) on the affected side in 6 patients and tight hamstrings in 24 patients. Imaging findings included 18 patients with right-side involvement, 12 with left-side involvement, and 4 with involvement on both sides. In 11 patients, spina bifida occulta was observed at S1 and 8 patients had a history of lumbar spondylolysis with 4 patients having concurrent sacral fatigue fractures. Physical therapy was performed concurrently with the cessation of exercise, and return to exercise was permitted if the pain had been relieved after 1 month. All patients returned to sports at a median of 48 days (range, 20-226 days) after symptom onset. However, 2 patients experienced recurrence (1 patient on the ipsilateral side and 1 patient on the contralateral side).
Conclusion:
Sacral stress fractures are not limited to long-distance runners in this population and can manifest as lower back pain or buttock pain in athletes participating in a variety of sports. Although the course of treatment was generally good, the possibility of recurrence must always be considered.
Behind production scheduling lies a trade-off between the comprehensive modeling of production system constraints and quick schedule provision. To realize mass customization, this trade-off must be ...addressed, requiring a model comprehensive enough for the automation of high-mix production yet quick in adapting to the dynamics of the production system. In this context, we propose a practical approach in which Flexible Job Shop Scheduling with Tool Switching Constraints, offering a model capable of representing a wide range of high-mix productions and Quantum Annealing are combined. The resulting schedules are demonstrated to be competitive, in terms of quality and computation time, are superior when compared with those obtained using Dispatching rules or Python MIP, respectively.
In this study, we introduce a measurement method for the bidirectional reflectance distribution function (BRDF) for curved surfaces. Nearly all BRDF measurements assume that the target surface is ...planar. This is because if the object is non-planar, the reflection angle changes from position to position, making accurate measurement impossible. However, most real objects are curved. We have overcome this problem by applying the paraboloid reflection principle. If the curved target surface is a paraboloid, the light focused on its focal point is reflected as parallel light, as in a parabolic antenna. The BRDF can be measured as the deviation angle from this parallel light direction. Here, we demonstrate that this can significantly improve the BRDF measurement accuracy for curved surfaces.
Gloss is associated significantly with material appearance, and observers often focus on gloss unevenness. Gloss unevenness is the intensity distribution of reflected light observed within a ...highlight area, that is, the variability. However, it cannot be analyzed easily because it exists only within the highlight area and varies in appearance across the reflection angles. In recent years, gloss has been analyzed in terms of the intensity of specular reflection and its angular spread, or the bidirectional reflectance distribution function (BRDF). In this study, we develop an apparatus to measure gloss unevenness that can alter the angle with an angular resolution of 0.02°. Additionally, we analyze the gloss unevenness and BRDF in terms of specular reflection. Using a high angular resolution, we measure and analyze high-gloss materials, such as mirrors and plastics, and glossy materials, such as photo-like inkjet paper and coated paper. Our results show that the magnitude of gloss unevenness is the largest at angles marginally off the center of the specular reflection angle. We discuss an approach for physically defining gloss unevenness based on the BRDF.
Purpose
This study investigated the characteristics of a new shielded diode detector, microSilicon X (model 60022: MSX), for small‐field and large‐field dosimetry.
Methods
The percent depth dose ...(PDD), beam profiles, detector output factor (OFdet), temperature dependence, dose rate dependence, dose‐per‐pulse (DPP) dependence, and dose‐response linearity of MSX were evaluated in Cyberknife and TrueBeam photon beams and compared with various detectors including microDiamond (PTW model 60019: MD), Sun Nuclear EDGE detector, Photon diode (PTW model 60016: PD), and semiflex ionization chamber (PTW model 31010: IC).
Results
For field sizes ranging from 50 × 50 mm2 to 400 × 400 mm2, MSX‐measured OFdet values were within 1% of the IC‐measured values. For the CyberKnife small fields, the maximum difference between the MSX‐measured OFdet and the MD‐measured field output factor (Ω) was 4.0%, while the maximum differences were 8.8% and 10.9% for PD and EDGE, respectively. MSX showed a stable response within 0.7% for water temperatures of 5°C to 34°C, while PD and EDGE showed a linear correlation between the water temperature and the response. MSX showed small variations within 0.2% for the dose rate, and PD and EDGE showed logarithmic increases in the response with the dose rate. MSX and MD had smaller DPP dependences than PD and EDGE.
Conclusions
The characteristics of MSX for measurements of small‐ and large‐field photon beams are favorable. Compared to PD, MSX exhibited significant improvement in the over‐response for small fields. The OFdet values measured by MSX were approximately in‐between those measured by MD and PD. MSX showed stable responses against water temperature, dose rate, and DPP variations and provided suitable data for a wide range of field sizes. However, careful attention is required for measurements of OFdet for field sizes of <10 × 10 mm2 and PDD for field sizes of ≥200 × 200 mm2.
Laminoplasty is the preferred operation for most patients with cervical myelopathy due to multilevel ossification of the posterior longitudinal ligament (OPLL). Recent studies have demonstrated ...several significant risk factors for poor clinical outcomes after laminoplasty, including older age, lower preoperative Japanese Orthopaedic Association (JOA) score, postoperative change in cervical alignment, cervical kyphosis, and high occupying ratio of the OPLL (that is, the ratio of the greatest anteroposterior thickness of the OPLL to the anteroposterior diameter of the spinal canal at the same level on a lateral image). However, the impact of dynamic factors on clinical outcomes is unclear. The purpose of this study is to assess the impact of dynamic factors on the clinical outcome after laminoplasty for cervical myelopathy due to OPLL.
A consecutive series of patients who underwent laminoplasty for cervical myelopathy due to OPLL between 2003 and 2009 was retrospectively reviewed. The indication for laminoplasty at the authors' hospital included preoperative straight or lordotic alignment of the cervical spine and an occupying ratio of OPLL less than 60%. The JOA score and recovery rate were used to evaluate clinical outcomes. A poor clinical outcome was defined as a recovery rate of less than 50%. Patient factors examined along with outcome included age, preoperative JOA score, preoperative somatosensory evoked potentials, preoperative motor evoked potentials, body mass index, and presence of high intensity on MRI. Radiographic measures included the preoperative C2-7 lordotic angle, preoperative C2-7 range of motion (ROM), preoperative segmental ROM at the level of myelopathy, and the occupying ratio of OPLL.
There were 45 patients (33 males and 12 females). The mean follow-up period was 4 years (range 2-6.8 years). The mean patient age was 66.9 years (range 50-85 years). The mean JOA score significantly increased from 9.1 before surgery to 13.1 at the final follow-up. The mean recovery rate was 51.2%. Nineteen patients (42%) had a recovery rate of less than 50%. Patient factors were not associated with surgical outcomes. Only the preoperative C2-7 ROM was significantly greater in the poor surgical outcome group (23.1° vs 14.1°). Receiver operating characteristic curve analysis showed that the optimal preoperative C2-7 ROM cutoff was 20°. Logistic regression analysis revealed that patients with a preoperative C2-7 ROM of greater than 20° had a 4.6 times higher risk (p = 0.021) of a poor clinical outcome, indicating that dynamic factors may have an impact on the surgical outcome of laminoplasty.
Fusion surgery may be a useful strategy in patients with preoperative hypermobility of the cervical spine.
Abstract
Halogenated solvents (e.g. chlorobenzene and chloroform) are typically used for hole-transporting materials (HTMs) in perovskite solar cells (PSCs); however, their use should be avoided as ...they are known to be hazardous to the environment. Herein, we synthesized a nonhalogenated-solvent-soluble, dopant-free HTM,
SF62
. When depositing HTMs for PSCs,
SF62
could be dissolved with a nonhalogenated and green solvent, ethyl acetate. It is one of the most common organic solvents and is known to have a low environmental impact. Non-doped
-SF62
-based PSCs exhibited higher power-conversion efficiency (18.6%) than doped 2,2′,7,7′-tetrakis(
N,N
-di-p-methoxyphenylamino)-9,9′-spirobifluorene (
Spiro-OMeTAD
)-based ones (18.3%), with enhanced stability.
A single-center retrospective study.
To research the predictive factors associated with postoperative patient satisfaction 1 year after minimally invasive transforaminal lumbar interbody fusion ...(MIS-TLIF), a minimally invasive procedure for lumbar degenerative disease.
There have been reports of numerous variables influencing patient satisfaction with lumbar surgery; however, there have been few investigations on MIS are limited.
This study included 229 patients (107 men and 122 women; mean age, 68.9 years) who received one or two levels of MISTLIF, and the patient's age, gender, disease, paralysis, preoperative physical functions, duration of symptom(s), and surgery-associated factors (waiting for surgery, number of surgical levels, surgical time, and intraoperative blood loss) were studied. Radiographic characteristics and clinical outcomes such as Oswestry Disability Index (ODI) scores and Visual Analog Scale (VAS; 0-100) ODI scores for low back pain, leg pain, and numbness were studied. One year following surgery, patient satisfaction (defined as satisfaction for surgery and for present condition; 0-100) was assessed using VAS and its relationships with investigation factors were examined.
The mean VAS scores of satisfaction for surgery and for present condition were 88.6 and 84.2, respectively. The results of multiple regression analysis showed that preoperative adverse factors of satisfaction for surgery were being elderly (β =-0.17, p =0.023), high preoperative low back pain VAS scores (β =-0.15, p =0.020), and postoperative adverse factors were high postoperative ODI scores (β =-0.43, p <0.001). In addition, the preoperative adverse factor of satisfaction for present condition was high preoperative low back pain VAS scores (β =-0.21, p =0.002), and postoperative adverse factors were high postoperative ODI scores (β =-0.45, p <0.001) and high postoperative low back pain VAS scores (β =-0.26, p =0.001).
According to this study, significant preoperative low back pain and high postoperative ODI score after surgery are linked to patient unhappiness.
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