Refraction, beam splitting and dispersion of GHz surface acoustic waves by a phononic crystal.

We exploit a time-resolved ultrafast optical technique to study the propagation of point-excited surface acoustic waves on a microscopic two-dimensional phononic crystal in the form of a square lattice of holes in a silicon substrate. Constant-frequency images and the dispersion relation are extracted, and the latter measured in detail in the region around the phononic band gap. Mode conversion and refraction at the interface between the phononic crystal and surrounding non-structured silicon substrate is studied at constant frequencies. Symmetric phonon beam splitting, for example, is shown to lead to a striking Maltese-cross pattern when phonons exit a square region of phononic crystal excited near its center.

Ethnic Differences in Western and Asian Sacroiliac Joint Anatomy for Surgical Planning of Minimally Invasive Sacroiliac Joint Fusion.

Pain originating in the sacroiliac joint (SIJ) is a contributor to chronic lower back pain. Studies on minimally invasive SIJ fusion for chronic pain have been performed in Western populations. Given the shorter stature of Asian populations compared with Western populations, questions can be raised regarding the suitability of the procedure in Asian patients. This study investigated the differences in 12 measurements of sacral and SIJ anatomy between two ethnic populations by analyzing computed tomography scans of 86 patients with SIJ pain. Univariate linear regression was performed to evaluate the correlations of body height with sacral and SIJ measurements. Multivariate regression analysis was used to evaluate systematic differences across populations. Most sacral and SIJ measurements were moderately correlated with body height. The anterior-posterior thickness of the sacral ala at the level of the S1 body was significantly smaller in the Asian patients compared with the Western patients. Most measurements were above standard surgical thresholds for safe transiliac placement of devices (1026 of 1032, 99.4%); all the measurements below these surgical thresholds were found in the anterior-posterior distance of the sacral ala at the S2 foramen level. Overall, safe placement of implants was allowed in 84 of 86 (97.7%) patients. Sacral and SIJ anatomy relevant to transiliac device placement is variable and correlates moderately with body height, and the cross-ethnic variations are not significant. Our findings raise a few concerns regarding sacral and SIJ anatomy variation that would prevent safe placement of fusion implants in Asian patients. However, considering the observed S2-related anatomic variation that could affect placement strategy, sacral and SIJ anatomy should still be preoperatively evaluated.

Three-Year Clinical Outcomes after Minimally Invasive Sacroiliac Joint Arthrodesis Using Triangular Implants in Japan: A Pilot Study of Five Cases.

INTRODUCTION: Sacroiliac joint (SIJ) arthrodesis using a minimally invasive technique, particularly the triangular implant system, is performed in patients with SIJ dysfunction in the United States and Europe. We report three-year clinical outcomes of the first minimally invasive SIJ arthrodesis procedures using the implants performed in Japan. METHODS: Five patients (one man and four women; age: 56.4±16.9 years) with SIJ pain who underwent SIJ arthrodesis using a triangular implant system in 2017 were included. In addition to operation time and blood loss, pain intensity (visual analog scale [VAS]) and functional impairment (Oswestry disability index [ODI]) were assessed preoperatively and at a 36-month follow-up. Implant loosening and osseous bridging across the joint were evaluated using computed tomography images, and patients' satisfaction with the surgery was also assessed at 12 and 36 months. RESULTS: The surgical time was 67.7±13.1 minutes, and blood loss was 7.4±6.9 mL. The mean VAS value improved significantly from 88.0±8.4 mm to 33.6±31.9 mm at 3 months and was maintained at 46.4±30.9 mm at 36 months (P<0.05). The mean ODI improved significantly from 76.4%±3.8% to 46.2%±21.9% at 6 months postoperatively (P<0.05) but had no significant improvements thereafter: 46.94±23.7% (12 months) and 66.4±8.6% (36 months). Three of five patients presented with at least one implant loosening on the sacrum side. No patient had osseous bridging across the joint. A total of 80% (4/5) of patients reported satisfaction with the surgery at 12 months and 60% (3/5) at 36 months. CONCLUSIONS: The mean VAS value and ODI significantly improved until 6 months after the surgery. However, the mean ODI was reaggravated at 36 months after the surgery. Osseous bridging across the joint was not observed in all patients. We should carefully keep an eye on further long-term results to evaluate the implant.

Nanostructured LiMnO2 with Li3PO4 Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox.

Nanostructured LiMnO2 integrated with Li3PO4 was successfully synthesized by the mechanical milling route and examined as a new series of positive electrode materials for rechargeable lithium batteries. Although uniform mixing at the atomic scale between LiMnO2 and Li3PO4 was not anticipated because of the noncompatibility of crystal structures for both phases, our study reveals that phosphorus ions with excess lithium ions dissolve into nanosize crystalline LiMnO2 as first evidenced by elemental mapping using STEM-EELS combined with total X-ray scattering, solid-state NMR spectroscopy, and a theoretical ab initio study. The integrated phase features a low-crystallinity metastable phase with a unique nanostructure; the phosphorus ion located at the tetrahedral site shares faces with adjacent lithium ions at slightly distorted octahedral sites. This phase delivers a large reversible capacity of ∼320 mA h g-1 as a high-energy positive electrode material in Li cells. The large reversible capacity originated from the contribution from the anionic redox of oxygen coupled with the cationic redox of Mn ions, as evidenced by operando soft XAS spectroscopy, and the superior reversibility of the anionic redox and the suppression of oxygen loss were also found by online electrochemical mass spectroscopy. The improved reversibility of the anionic redox originates from the presence of phosphorus ions associated with the suppression of oxygen dimerization, as supported by a theoretical study. From these results, the mechanistic foundations of nanostructured high-capacity positive electrode materials were established, and further chemical and physical optimization may lead to the development of next-generation electrochemical devices.

Sarcopenia is associated with worse recovery of physical function and dysphagia and a lower rate of home discharge in Japanese hospitalized adults undergoing convalescent rehabilitation.

OBJECTIVE: The aim of this study was to evaluate the effect of sarcopenia on functional outcomes, including activities of daily living (ADLs); dysphagia status; and the rate of home discharge, among hospitalized adults receiving convalescent rehabilitation. METHODS: A retrospective cohort study was conducted with 898 patients newly admitted to in-hospital convalescent rehabilitation wards at a single rehabilitation hospital in Japan. Baseline sarcopenia was diagnosed using muscle mass index and handgrip strength according to the criteria of the European Working Group on Sarcopenia in Older People, with the cutoff values of the Asian Working Group for Sarcopenia. The primary outcome was ADLs, assessed by Functional Independence Measure motor (FIM-motor) score at hospital discharge. The secondary outcomes included dysphagia, assessed by the Food Intake Level Scale (FILS), at discharge, and the rate of home discharge. Three multivariate analyses revealed an association between sarcopenia and the clinical outcomes. Each analysis adjusted for the following confounders: age, sex, time from onset, premorbid ADLs, comorbidities, cognitive level, nutritional status, major drugs, and admission diagnoses. RESULTS: After enrollment, 795 patients (mean age 74.9 ± 13.2 y; 59% women) were included in the final analysis. Admission diagnoses included stroke (n = 276; 34.7%), musculoskeletal disorders (n = 382; 48.1%), and hospital-associated deconditioning (n = 137; 17.2%). Of the 795 patients examined, 402 (50.6%) had sarcopenia. The multiple linear regression analysis showed that sarcopenia was independently associated with FIM motor score at discharge in patients with all disease types (ß = -0.189 [stroke], -0.240 [musculoskeletal disorders], -0.230 [hospital-associated deconditioning]; all P < 0.05), with FILS score at discharge only in patients with musculoskeletal disorders (ß = -0.271, P < 0.001), but not in patients with stroke (ß = -0.061, P = 0.375) or those with hospital-associated deconditioning (ß = -0.131, P = 0.070). The multiple logistic regression analysis showed that sarcopenia was associated with rate of home discharge in all disease types (odds ratio [OR], 0.201; 95% confidence interval [CI], 0.067-0.597 for stroke; OR, 0.242; 95% CI, 0.076-0.772 for musculoskeletal disorders; OR, 0.121; 95% CI, 0.110-0.347 for hospital-associated deconditioning; all P < 0.05). CONCLUSIONS: Sarcopenia is associated with worse recovery of ADLs and dysphagia and a lower rate of home discharge in hospitalized adults undergoing convalescent rehabilitation. Early detection of sarcopenia and treatment by rehabilitation nutrition should be implemented in this population.

Extent of Spin Contamination Errors in DFT/Plane-wave Calculation of Surfaces: A Case of Au Atom Aggregation on a MgO Surface.

The aggregation of Au atoms onto a Au dimer (Au2) on a MgO (001) surface was calculated by restricted (spin-un-polarized) and unrestricted (spin-polarized) density functional theory calculations with a plane-wave basis and the approximate spin projection (AP) method. The unrestricted calculations included spin contamination errors of 0.0⁻0.1 eV, and the errors were removed using the AP method. The potential energy curves for the aggregation reaction estimated by the restricted and unrestricted calculations were different owing to the estimation of the open-shell structure by the unrestricted calculations. These results show the importance of the open-shell structure and correction of the spin contamination error for the calculation of small-cluster-aggregations and molecule dimerization on surfaces.

Effects of branched-chain amino acids and vitamin D supplementation on physical function, muscle mass and strength, and nutritional status in sarcopenic older adults undergoing hospital-based rehabilitation: A multicenter randomized controlled trial.

AIM: To investigate the effects of branched-chain amino acids and vitamin D supplementation on physical function, muscle strength, muscle mass, and nutritional status in sarcopenic older adults undergoing hospital-based rehabilitation. METHODS: We carried out an 8-week, multicenter, randomized, controlled, blinded outcome, two-cohort parallel group intervention trial of sarcopenic older adults undergoing in-hospital rehabilitation. The eligibility criteria included older adults (aged ≥65 years) with low muscle strength (handgrip strength) and low muscle mass (calf circumference) according to the cut-off values for older Asians. The intervention group received branched-chain amino acids and vitamin D supplementation, whereas the control group did not. Both groups underwent low-intensity resistance training in addition to the post-acute rehabilitation program. The primary outcome of physical function (Functional Independence Measure-motor scores), and the secondary outcomes of muscle strength (handgrip strength), muscle mass (calf circumference) and nutritional status (body mass index) were measured at baseline and at the end of the intervention. RESULTS: Finally, a total of 68 patients were analyzed (intention-to-treat analysis): 35 in the intervention group and 33 in the control group. Functional Independence Measure-motor scores increased significantly in both groups over time (P < 0.05). However, no treatment-by-time effects were observed (median estimated difference 2.4, 95% confidence interval -1.2 to 7.1). Handgrip strength, calf circumference and body mass index increased significantly in both groups over time (P < 0.05), with significantly greater improvements in the intervention group (P = 0.041, 0.033 and 0.035, respectively). CONCLUSIONS: We showed that an 8-week intervention of branched-chain amino acids and vitamin D supplementation with low-intensity resistance training improves muscle-related outcomes in sarcopenic older adults undergoing hospital-based rehabilitation (UMIN000006238). Geriatr Gerontol Int 2019; 19: 12-17.

Theoretical study of correlations between the coordination structures and catalytic activities in polymer-stabilized au nanocluster catalysts.

Au nanoclusters (Au NCs) stabilized by poly(N-vinyl-2-pyrrolidone) and poly(allylamine), abbreviated to Au:PVP and Au:PAA, catalyze the aerobic oxidation of p-hydroxybenzyl alcohols, but the catalytic activity of Au:PVP is much higher than that of Au:PAA. To elucidate the correlations between the catalytic activities and coordination structures of the stabilizing polymer, the substrate accessibility on Au NCs was estimated by density functional theory (DFT) and molecular dynamics (MD) calculations. For MD simulations, we applied a systematic method to optimize the temperature parameters in temperature replica exchange molecular dynamics (T-REMD), and the coordination structures were comprehensively classified by multivariate analysis. The results show that the number of open active sites on the Au NCs is a good index for predicting the catalytic activities. © 2018 Wiley Periodicals, Inc.

Hospital dental hygienist intervention improves activities of daily living, home discharge and mortality in post-acute rehabilitation.

AIM: To examine the effects of oral management provided by dental hygienists (DH) on patient outcomes in post-acute rehabilitation. METHODS: We carried out a retrospective cohort study with 1056 patients newly admitted to a post-rehabilitation hospital in Japan. DH care was defined as two or more consecutive instances of oral management provided by a ward DH during hospitalization. The primary outcome was the motor domain of Functional Independence Measure score at discharge. Other outcomes included the rate of home discharge; length of stay, all-cause in-hospital mortality, and oral, swallowing and nutritional status at discharge. Propensity score matching was carried out to control and adjust for patients' backgrounds to compare outcomes between patients who did or did not receive DH care. RESULTS: Of 1056 patients enrolled (mean age 71 years; 52.0% women; 73.1% with oral problems), 415 (39.3%) received DH care. Multivariate analyses using pair-matched patients showed that DH care was significantly associated with higher motor domain of Functional Independence Measure score at discharge (ß = 0.281, P = 0.041), shorter length of stay (ß = 0.446, P = 0.044), higher rate of home discharge (odds ratio 1.202, 95% confidence interval 1.026-1.491, P = 0.037) and lower mortality (hazard ratio 0.818, 95% confidence interval 0.738-0.952, P = 0.037) after adjusting for potential covariates. CONCLUSIONS: DH oral management improves patient outcomes, including activities of daily living, home discharge and in-hospital mortality in post-acute rehabilitation. Early detection of oral problems, early oral treatment by dental professionals, and cooperation between medical and dental professionals should be implemented. Geriatr Gerontol Int 2019; 19: 189-196.

Systemic Inflammation in the Recovery Stage of Stroke: Its Association with Sarcopenia and Poor Functional Rehabilitation Outcomes.

OBJECTIVE: The aim of our study was to investigate how systemic inflammation relates to sarcopenia and its impact on functional outcomes in the recovery stages of stroke. METHODS: A retrospective cohort study was performed in consecutive patients admitted to convalescent rehabilitation wards following stroke. Patients with acute or chronic high-grade inflammatory diseases were excluded. Systemic inflammation was evaluated using the modified Glasgow Prognostic Score (mGPS). Sarcopenia was defined as a loss of skeletal muscle mass and decreased muscle strength, with the cut-off values set by the Asian Working Group for Sarcopenia. The primary outcome was the motor domain of the Functional Independence Measure (FIM-motor). Univariate and multivariate analyses were used to determine whether mGPS was associated with sarcopenia and FIM-motor at discharge. RESULTS: The study included 204 patients (mean age 74.1 years, 109 men). mGPS scores of 0, 1, and 2 were assigned to 149 (73.0%), 40 (19.6%), and 13 (6.4%) patients, respectively. Sarcopenia was diagnosed in 81 (39.7%) patients and was independently associated with stroke history (odds ratio [OR] 1.890, P=0.027), premorbid modified Rankin scale (OR 1.520, P=0.040), body mass index (OR 0.858, P=0.022), and mGPS score (OR 1.380, P=0.021). Furthermore, the mGPS score was independently associated with sarcopenia (OR 1.380, P=0.021) and FIM-motor at discharge (ß=-0.131, P=0.031). CONCLUSION: Systemic inflammation is closely associated with sarcopenia and poor functional outcomes in the recovery stage of stroke. Early detection of systemic inflammation and sarcopenia can help promote both adequate exercise and nutritional support to restore muscle mass and improve post-stroke functional recovery.

A Diagnostic Scoring System for Sacroiliac Joint Pain Originating from the Posterior Ligament.

Objective: Sacroiliac joint (SIJ) pain originating from the posterior ligament manifests in not only the buttocks but also the groin and lower extremities and thus may be difficult to discern from pain secondary to other lumbar disorders. We aimed to develop a simple clinical diagnostic tool to help physicians distinguish between patients with SIJ pain originating from the posterior ligament and those with lumbar disc herniation (LDH) or lumbar spinal canal stenosis (LSS). Design: Prospective case-control study. Patients and Methods: We evaluated 62 patients with SIJ pain originating from the posterior ligament and 59 patients with LDH and LSS. Pain areas, pain increasing positions, provocation test, and tenderness points were investigated. A scoring system based on multivariate logistic regression equations using the investigated items was developed. Results: Two pain areas (the posterosuperior iliac spine (PSIS) detected by the one-finger test and groin), pain while sitting on a chair, provocation test, and two tenderness points (PSIS and the sacrotuberous ligament) had high odds ratios (range, 25.87­1.40) and were used as factors in the scoring system. An integer score derived from the regression coefficient and clinical experience was assigned to each identified risk factor. The sum of the risk score for each patient ranged from 0­9. This scoring system had a sensitivity of 90.3% and a specificity of 86.4% for a positivity cutoff point of 4. Conclusion: The scoring system can help distinguish between patients with SIJ pain originating from the posterior ligament and those with LDH and LSS.

Advances in Gold Catalysis and Understanding the Catalytic Mechanism.

When gold is deposited as nanoparticles (NPs) with mean diameters of 2-5 nm or clusters with mean diameters below 2 nm onto a variety of supports such as metal oxides, carbons, polymers, etc., the supported Au NPs exhibit unique catalytic properties, while bulk Au is almost inert as a catalyst. A lot of research works indicate that the key factors of the catalysis by supported Au NPs are the selection of the supports, the control of the Au NP size, the shape of the Au NPs, and the strong junction between Au NPs and the supports, because the perimeter zone around Au NPs acts as the active site for many reactions. In order to elucidate the origin of catalysis by supported Au NPs, the interplay between physicochemical analysis, computational studies, and rational experiments for catalysis by supported Au NPs is becoming more and more important. This article summarizes our experiences and progress in such interplay.

The diagnostic value of single-photon emission computed tomography/computed tomography for severe sacroiliac joint dysfunction.

PURPOSE: We aimed to evaluate the value of single-photon emission computed tomography (SPECT)/computed tomography (CT) for the diagnosis of sacroiliac joint (SIJ) dysfunction. METHODS: SPECT/CT was performed in 32 patients with severe SIJ dysfunction, who did not respond to 1-year conservative treatment and had a score of >4 points on a 10-cm visual analog scale. We investigated the relationship between the presence of severe SIJ dysfunction and tracer accumulation, as confirmed by SPECT/CT. In cases of bilateral SIJ dysfunction, we also compared the intensity of tracer accumulation on each side. Moreover, we examined the relationship between the intensity of tracer accumulation and the different treatments the patients subsequently received. RESULTS: All 32 patients with severe SIJ dysfunction had tracer accumulation with a standardized uptake value (SUV) of >2.2 (mean SUV 4.7). In the 19 patients with lateralized symptom intensity, mean SUVs of the dominant side were significantly higher than those of the nondominant side. In 10 patients with no lateralization, the difference in the SUVs between sides was <0.6. Patients exhibiting higher levels of tracer accumulation required more advanced treatment. CONCLUSION: Patients with higher levels of tracer accumulation had greater symptom severity and also required more advanced treatment. Thus, we believe that SPECT/CT may be a suitable supplementary diagnostic modality for SIJ dysfunction as well as a useful technique for predicting the prognosis of this condition.

An open-label, long-term study examining the safety and tolerability of pregabalin in Japanese patients with central neuropathic pain.

PURPOSE: Studies of pregabalin for the treatment of central neuropathic pain have been limited to double-blind trials of 4-17 weeks in duration. The purpose of this study was to assess the long-term safety and tolerability of pregabalin in Japanese patients with central neuropathic pain. The efficacy of pregabalin was also assessed as a secondary measure. PATIENTS AND METHODS: This was a 53-week, multicenter, open-label trial of pregabalin (150-600 mg/day) in Japanese patients with central neuropathic pain due to spinal cord injury, multiple sclerosis, or cerebral stroke. RESULTS: A total of 103 patients received pregabalin (post-stroke =60; spinal cord injury =38; and multiple sclerosis =5). A majority of patients (87.4%) experienced one or more treatment-related adverse events, most commonly somnolence, weight gain, dizziness, or peripheral edema. The adverse event profile was similar to that seen in other indications of pregabalin. Most treatment-related adverse events were mild (89.1%) or moderate (9.2%) in intensity. Pregabalin treatment improved total score, sensory pain, affective pain, visual analog scale (VAS), and present pain intensity scores on the Short-Form McGill Pain Questionnaire (SF-MPQ) and ten-item modified Brief Pain Inventory (mBPI-10) total score at endpoint compared with baseline. Improvements in SF-MPQ VAS and mBPI-10 total scores were evident in all patient subpopulations. Mean changes from baseline in SF-MPQ VAS and mBPI-10 scores at endpoint were -20.1 and -1.4, respectively. CONCLUSION: These findings demonstrate that pregabalin is generally well tolerated and provides sustained efficacy over a 53-week treatment period in patients with chronic central neuropathic pain.

Percutaneous drainage combined with hyperbaric oxygen therapy for pyogenic spondylitis with iliopsoas abscess.

STUDY DESIGN: A retrospective study. PURPOSE: The purpose of this study was to evaluate outcomes in patients with pyogenic spondylitis accompanied by iliopsoas abscess who were treated by percutaneous drainage combined with hyperbaric oxygen (HBO) therapy. OVERVIEW OF LITERATURE: To the best of our knowledge, there have been no previous reports of the use of percutaneous drainage combined with HBO therapy for the treatment of this condition. METHODS: Twenty-three patients (13 men, 10 women; mean age, 69.0 years; range, 45-85 years) were treated with percutaneous drainage combined with HBO therapy in addition to commonly used conservative therapy. Mean follow-up duration was 27.7 months (range, 12-48 months). Clinical outcomes and imaging examinations were retrospectively investigated. RESULTS: Symptoms such as low back pain, radicular pain, and hip pain resolved in all patients immediately after treatment. Mean time from the start of treatment to the return of C-reactive protein levels to normal or baseline values recorded before the onset of spondylitis was 28.3 days (range, 8-56 days). In the final set of follow-up radiographic studies, all patients were free from progressive destructive changes. Follow-up magnetic resonance images or computed tomography with contrast enhancement confirmed the disappearance or near-total resolution of the iliopsoas abscess cavity with healing of the pyogenic spondylitis in all 23 patients. No recurrences were observed during follow-up. CONCLUSIONS: The present study suggests that patients with pyogenic spondylitis accompanied by iliopsoas abscess can be cured without a prolonged period of therapy or recurrence using this treatment.

Distractive flexion injuries of the subaxial cervical spine treated with a posterior procedure using cervical pedicle screws or a combined anterior and posterior procedure.

The purpose of this study was to compare the clinical and radiographic outcomes of patients with distractive flexion (DF) injuries of the subaxial cervical spine who had undergone a posterior procedure using cervical pedicle screw (CPS) fixation with those who had undergone a combined anterior and posterior procedure. Recommendations for the surgical treatment of DF injuries of the subaxial cervical spine remain controversial. There are few clinical reports of posterior CPS fixation for DF injuries. We retrospectively reviewed the clinical records and radiographs of 50 consecutive patients with DF injuries of the subaxial cervical spine treated at the Imakiire General Hospital. Group 1 consisted of 24 patients who underwent posterior wiring fixation and fusion with additional anterior decompression and fusion. Group 2 consisted of 26 patients who underwent posterior decompression and fusion with CPS fixation. Group 1 had a significantly longer operation time (295.4 minutes) than Group 2 (163.3 minutes). Group 1 had significantly higher blood loss (689.1g) than Group 2 (313.7 g). No patient in Group 1 or 2 developed postoperative neurological worsening. The mean loss of kyphotic correction was 1.6° and 0.1° in Groups 1 and 2, respectively, and the loss of kyphotic correction in Group 2 was significantly less than that of Group 1. We suggest that posterior procedures with CPS fixation are reasonable for the management of cervical DF injuries.

The use of antibiotic-impregnated fibrin sealant for the prevention of surgical site infection associated with spinal instrumentation.

PURPOSE: The purpose of this study was to determine if the use of antibiotic-impregnated fibrin sealant (AFS) was effective in preventing surgical site infections (SSI) associated with spinal instrumentation. METHODS: In a preliminary study, five pieces of vancomycin-impregnated fibrin sealant, five nuts that were not treated with the sealant, and five nuts that were treated with the sealant were subjected to agar diffusion testing. In a clinical study, the rates of deep SSI were compared between 188 patients who underwent procedures involving spinal instrumentation without AFS (group 1) and 196 patients who underwent procedures involving spinal instrumentation with AFS (group 2). RESULTS: All five pieces of vancomycin-impregnated fibrin sealant and the five nuts treated with the sealant exhibited antimicrobial efficacy, while the five untreated nuts did not exhibit antimicrobial efficacy in the agar diffusion test. In the clinical study, 11 (5.8 %) of the 188 patients in group 1 acquired a deep SSI, while none (0 %) of the 196 patients in group 2 acquired a deep SSI. CONCLUSION: The present study demonstrated that the application of AFS to spinal instrumentation yielded good clinical outcomes in terms of the prevention of postoperative spinal infections. It is hoped that limiting AFS use to patients requiring spinal instrumentation and those with risk factors for SSI will reduce the overall costs while preventing SSIs.

Subdural spread of injected local anesthetic in a selective transforaminal cervical nerve root block: a case report.

INTRODUCTION: Although uncommon, selective cervical nerve root blocks can have serious complications. The most serious complications that have been reported include cerebral infarction, spinal cord infarction, transient quadriplegia and death. CASE PRESENTATION: A 40-year-old Japanese woman with a history of severe right-sided cervical radicular pain was scheduled to undergo a right-sided C6 selective cervical nerve root block using a transforaminal approach under fluoroscopic guidance. An anterior oblique view of the C5-C6 intervertebral foramen was obtained, and a 23-gauge spinal needle, connected to the normal extension tube with a syringe filled with contrast medium, was introduced into the posterior-caudal aspect of the C5-C6 intervertebral foramen on the right side. In the anteroposterior view, the placement of the needle was considered satisfactory when it was placed no more medial than halfway across the width of the articular pillar. Although the spread of the contrast medium along the C6 nerve root was observed with right-sided C6 radiculography, the subdural flow of the contrast medium was not observed with real-time fluoroscopy. The extension tube used for the radiculography was removed from the spinal needle and a normal extension tube with a syringe filled with lidocaine connected in its place. We performed a negative aspiration test and then injected 1.5 mL of 1.0% lidocaine slowly around the C6 nerve root. Immediately after the injection of the local anesthetic, our patient developed acute flaccid paralysis, complained of breathing difficulties and became unresponsive; her respiratory pattern was uncoordinated. After 20 minutes, she regained consciousness and became alert, and her muscle strength in all four limbs returned to normal without any sensory deficits after receiving emergent cardiorespiratory support. CONCLUSIONS: We believe that confirming maintenance of the appropriate needle position in the anteroposterior view by injecting local anesthetic is important for preventing central needle movement. Because the potential risk of serious complications cannot be completely eliminated during the use of any established selective cervical nerve root block procedure, preparation for an emergency airway, ventilation and cardiovascular support is indispensable in cases of high spinal cord anesthesia.

Facet arthrography of a cervical synovial cyst.

A rare case is presented of a synovial cyst located at the level of C3-C4 that caused cervical myelopathy and that was preoperatively diagnosed by facet arthrography. A woman in her late seventies experienced muscle weakness and numbness in her right upper extremity and gait disturbance. MRI revealed an extradural lesion located dorsolaterally on the right side of the spinal cord at the level of C3-C4. CT facet arthrography revealed continuity of the extradural lesion with the right C3-C4 facet joint and infiltration of contrast medium into the lesion. Postoperatively, histological examination of the cyst showed fibrous tissue with calcium deposits and the presence of synovial lining. Preoperatively, cervical synovial cysts are often difficult to distinguish from other extradural lesions. In this case, facet arthrography allowed the preoperative determination of communication between the extradural lesion and the facet joint, leading to the diagnosis of a synovial cyst.

Cervical pedicle screw insertion using a gutter entry point at the transitional area between the lateral mass and lamina.

PURPOSE: The purpose of this study was to describe a free-hand pedicle screw insertion technique and to evaluate the accuracy of pedicle screw placement and validity of pedicle screw fixation in patients with subaxial cervical spine injuries. METHODS: We retrospectively reviewed 32 consecutive patients with subaxial cervical spine injuries who underwent posterior cervical fixation using our cervical pedicle screw (CPS) insertion technique. We also assessed the clinical and radiological outcomes and the accuracy of pedicle screw placement. RESULTS: The mean preoperative kyphosis was 4.0°, which was corrected to -5.2° after the operation, and the mean kyphosis angle was -4.4° at the final follow-up. The mean preoperative disc height ratio was 81.9%, and it improved to 105.4% after the operation, which was maintained until the final follow-up measurement of 103.4%. Bony union was achieved, and there were no instrumentation failures in any patient. Overall, 127 pedicle screws were inserted, of which 112 (88.1%) were classified as grade 1 (exact intrapedicular screw positioning), 10 (7.8%) as grade 2 (perforation <50% of the screw diameter), and 5 (3.9%) as grade 3 (perforation more than 50% of the screw diameter). CONCLUSION: In our technique, a gutter is created using a high-speed burr at the transitional area between the lateral mass and lamina similar to the procedure in double-door laminoplasty to identify an entry point for CPS insertion. It is easy for general spine surgeons to identify a CPS insertion entry point using our technique.