Reapplication of the Pavlik Harness for Treatment of Developmental Dysplasia of the Hip After Initial Pavlik Harness Failure

OBJECTIVE

The Pavlik harness (PH) has been widely used as the standard treatment for infants with developmental dysplasia of the hip (DDH). When the initial application of the PH fails, alternative treatments, such as closed reduction, open reduction, and reapplication of the PH will be considered. Compared with other treatments, reapplication of the PH offers certain advantages, including simplicity and reduced physical, and psychological stress, on both infants and caregivers. This study aims to investigate the effectiveness of reapplying the PH in patients with DDH.

METHODS

This study included patients with DDH (complete dislocation) who were treated by reapplication of PH between 1988 and 2012. Patients who were able to follow-up for more than 5 years were included. We examined the reduction rate and several factors to identify indicators associated with successful reduction during reapplication, including age, sex, side of hip dislocation, and the presence of the Ortolani sign. At the final follow-up, hip development was assessed using the Severin classification, whereas avascular necrosis (AVN) was evaluated using the Kalamchi classification and the Salter criteria.

RESULTS

A total of 56 patients (48 females and 8 males) and 57 hips were included in this study. The mean age at first and second application of PH was 4.2 months old (range: 0.12 to 6.4), and 5.8 months old (3.0 to 11.4), respectively. The reduction rate was 49% (28 out of 57 hips). Among the successfully reduced hips, the AVN rate was 3.6% (1 out of 28 hips). The Severin classification revealed 27 hips in class I and 1 hip in class III. Statistical analysis indicated a significantly higher proportion of left hip involvement in the reduction group (85% vs 41%, χ 2 test, P < 0.001). Although not statistically significant, the rate of positive Ortolani sign tended to be higher in the reduction group (61% vs 38%, χ 2 test, P = 0.06).

CONCLUSION

The reapplication method demonstrated a 49% reduction rate and a low AVN rate of 3.6% in our study. It is worth considering for patients who fail the initial PH treatment, particularly in cases of left-side dislocation and a positive Ortolani sign during the initial application.

Experimental and quantitative evaluation of frequency modulation caused by Doppler effect around high-speed moving sound source

High-speed train noise remains a wayside environmental issue. For accurate noise prediction, the characteristics of a moving sound source must be revealed. In this work, the frequency modulation of sound waves emitted from a high-speed moving sound source was experimentally investigated. In the experiment, the sound field around a running train model emitting a 40 kHz pure tone was measured by an optical measurement technique, parallel phase-shifting interferometry, which can visualize instantaneous sound fields. For quantitative evaluation, a lens distortion correction was also developed and adopted for the visualization results. From the measured result of a sound source moving at a running speed of 280 km/h, the frequency modulation, known as the Doppler effect, was observed, and the measured frequency agreed well with the theoretical values.

Radiologic Changes After 10 Years Postreduction in Developmental Dysplasia of the Hip Treated With Different Reduction Methods and Risk Factors for Osteoarthritis

BACKGROUND

This study examined how radiologic indices at 10 years postreduction change over time and influence the final outcome through a comparative study of 3 reduction methods for developmental dysplasia of the hip, including the Pavlik harness, closed reduction, and open reduction (OR).

METHODS

Patients treated from 1990 to 2000 for dysplasia of the hip and followed up for >20 years were included in this study. Radiologic indices at 10 years postreduction and final follow-up (average 24 years postreduction) were measured in the 3 groups. The relative joint space of <66% compared with the healthy side was defined as positive osteoarthritis (OA) at the final follow-up. The relationship between OA and factors such as age, sex, method of reduction, radiologic indices, and Severin and Kalamchi classifications at 10 years postreduction were examined. Clinical evaluation was performed using the modified Harris Hip Score; a score of ≥80 was defined as good performance at the final follow-up.

RESULTS

Sixty-five patients (totaling 74 hips) were included. There were no significant differences in radiologic indices between the 10-year postreduction time and final follow-up. Excluding 9 bilateral patients, based on the relative joint space, 21% of the patients (13/56 hips), were positive for OA. Univariate analysis showed that the incidence of positive OA was significantly associated with OR and Kalamchi grade 4 at 10 years postreduction. The modified Harris Hip Score was 80 or higher in 90% of the cases at the final follow-up.

CONCLUSIONS

No significant changes in hip morphology were observed at 10 years postreduction. The Kalamchi classification at 10 years postreduction and OR were significantly associated with the incidence of OA at the final follow-up. Therefore, patients who undergo OR and/or display Kalamchi grade 4 have a high risk of developing OA and would require individual instructions for their daily lives to prevent further progression of OA and longer follow-up.

LEVEL OF EVIDENCE

Level Ⅲ-case-control study.

Determination of microphone acoustic center from sound field projection measured by optical interferometry

This article presents a method for determining the acoustic center of a microphone from a sound field measured by optical interferometry. The acoustic center defines the equivalent point source position of a microphone serving as a sound source where the spherical waveform starts to diverge. The value is used to determine the effective distance between microphones for free-field reciprocity calibration. Conventionally, it is determined from the inverse distance law properties of a point source using the transfer function method. In this study, the acoustic center was determined from the projection of the sound field of the microphone. Parallel phase-shifting interferometry was used to measure the line integration of the sound pressure from a microphone. The acoustic center is determined as the position where the squared error between the measured data and the projection model of a point source is minimized. Experiments with the B&K 4180 (Brüel & Kjær, Nærum, Denmark) microphone were performed for frequencies from 10 to 50 kHz. The best acoustic center estimation was obtained at a microphone distance of 0 mm, with a difference of 0.17 mm to the IEC 61094-3 value and 0.36 mm to the Barrera-Figueroa et al. [J. Acoust. Soc. Am. 120(5), 2668-2675 (2006)] result at a measurement frequency of 20 kHz.

Speckle holographic imaging of a sound field using Fresnel lenses

In this Letter, we propose to use Fresnel lenses for holographic sound-field imaging. Although a Fresnel lens has never been used for sound-field imaging mainly due to its low imaging quality, it has several desired properties, including thinness, lightweight, low cost, and ease of making a large aperture. We constructed an optical holographic imaging system composed of two Fresnel lenses used for magnification and demagnification of the illuminating beam. A proof-of-concept experiment verified that the sound-field imaging with Fresnel lenses is possible by using the spatiotemporally harmonic nature of sound.

Improvements in Intractable Lumbar and LowerExtremity Symptoms after Systemic Administration of Tocilizumab, an Anti-interleukin-6 Receptor Antibody

Study Design

Prospective cohort study (open-label, single-arm, and non-blinded).

Purpose

This study aims to determine the effects of systemic administration of tocilizumab, an anti-interleukin-6 (IL-6) receptor antibody on refractory low back pain and leg symptoms.

Overview of Literature

IL-6 overexpression is associated with neuropathic pain pathogenesis, which is potentially followed by chronic low back pain, including leg pain and numbness. This finding suggest that inhibition of IL-6 at the site of pain or in the transmission pathway could provide novel therapeutic targets for chronic low back pain.

Methods

This prospective, single-arm study included 11 patients (eight men; mean age, 62.7 years) with ≥3-months’ chronic pain history due to lumbar disease. Subcutaneous TCZ injections were administered twice, at a 2-week interval. We evaluated low back pain, leg pain, and leg numbness using numeric rating scales and the Oswestry Disability Index (ODI; baseline and 6 months postinjection); serum IL-6 and tumor necrosis factor-α levels (baseline and 1 month postinjection); and clinical adverse events.

Results

Intractable symptoms reduced after TCZ administration. Low back pain improved for 6 months. Improvements in leg pain and numbness peaked at 4 and 1 month, respectively. Improvements in ODI were significant at 1 month and peaked at 4 months. Serum IL-6 was increased at 1 month. IL-6 responders (i.e., patients with IL-6 increases >10 pg/mL) showed particularly significant improvements in leg pain at 2 weeks, 1 month, and 2 months compared with nonresponders. We observed no apparent adverse events.

Conclusions

Systemic TCZ administration improved symptoms effectively for 6 months, with peak improvements at 1–4 months and no adverse events. Changing serum IL-6 levels correlated with leg pain improvements; further studies are warranted to elucidate the mechanistic connections between lumbar disorders and inflammatory cytokines.

Prediction of atrial fibrillation by 12-lead electrocardiogram parameters in patients without structural heart disease

Background

Recently, the analysis of electrocardiogram (ECG) waveform by artificial intelligence has been reported to pick out those who have atrial fibrillation (AF) or have a high potential of developing AF, which, however, cannot explain the mechanisms or algorisms for the prediction from its nature.

Purpose

The purpose of this study is to conduct a comprehensive analysis to investigate the difference of weighting in predicting capability for AF among hundreds of automatically-measured ECG parameters using a single ECG at sinus rhythm.

Methods and results

Out of Shinken Database 2010–2017 (n=19170), 12825 patients were extracted, where those with ECG showing AF rhythm at the initial visit (including all persistent/permanent AF and a part of paroxysmal AF) and those with structural heart diseases were excluded. Out of 639 automatically-measured ECG parameters in MUSE data management system (GE Healthcare, USA), 438 were used. [Analysis 1] A predicting model for paroxysmal AF were determined by logistic regression analysis (Total, n=12825; paroxysmal AF, n=1138), showing a high predictive capability (AUC = 0.780, p&lt;0.001). In this model, the relative contribution of ECG parameters (by coefficient of determination) according to the time phase were P:72.4%, QRS:32.7%, and ST-T:13.7%, respectively (Figure A). [Analysis 2] Excluding AF at baseline, a predicting model for new-developed AF were determined by Cox regression analysis (Total, n=11687; new-developed AF, n=87), showing a high predictive capability (AUC = 0.887, p&lt;0.001). In this model, the relative contribution of parameters (by log likelihood) according to the time phase were P:40.8%, QRS:42.5%, and ST-T:24.9%, respectively (Figure B).

Conclusions

We determined ECG parameters that potentially contribute to picking up existing AF or predicting future development of AF, where the measurement of P wave strongly contributed in the former whereas all time phases were similarly important in the latter.

Weighting of parameters to predict AF

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): Self funding of the institute

Seeing the sound of castanets: Acoustic resonances between shells captured by high-speed optical visualization with 1-mm resolution

Sound fields radiated from the castanet, a Spanish percussive instrument comprising two shells, were optically visualized. A measurement system, which used parallel phase-shifting interferometry and a high-speed polarization camera, enabled the capture of instantaneous sound fields around the castanets, while the castanets were played, with the spatial resolution of 1.1 mm and frame rate of 100 000 fps. By carefully aligning the tilt of the castanets, the sound fields within the 1-mm gaps between both the shells were captured. From the visualization results, two acoustic resonances between the shells were identified. The first mode appeared between 1000 and 2000 Hz and exhibited a frequency chirp of several hundred hertz for several milliseconds after the impact. This can be explained by the Helmholtz resonance with a time-varying resonator shape, which is caused by the movement of the shells after impact. The second mode showed a resonance pattern with a single nodal diameter at the center of the shells, i.e., the standing wave mode caused by the interior volume. These physical phenomena involved in the sound radiation were identified owing to the unique features of the optical imaging method, such as contactless nature and millimeter-resolution imaging of instantaneous pressure fields.

Heart rate recovery after exercise as a prognostic predictor in patients with atrial fibrillation

Background

A delayed heart rate recovery (HRR) after exercise is related to mortality in sinus rhythm. This study aimed to investigate this concept can be applied to patients with atrial fibrillation (AF).

Methods

We analyzed 483 patients with AF (mean 65 years, male 74%). HRR integral was calculated by integrating the difference in HR in every 3 second between the end of exercise and the specified time after the exercise (30, 60, 120 and 180 seconds). After evaluating the prognostic power of each HRR integral, we selected HRR integral of 180 seconds (180HRR-integral).

Results

We divided the patients into two groups using median value of 180HRR-integral. All-cause mortality, the incidence of cardiovascular events and heart failure events were higher in the poor 180HRR-integral. After adjustment for covariates, the impact of the high 180HRR-integral for all-cause mortality was 3.15 (p=0.057), 1.77 for cardiovascular events (p=0.067) and 1.28 for heart failure events (p=0.519).

Conclusion

Poor HRR was associated with worse prognosis in patients with AF.

Funding Acknowledgement

Type of funding source: None

Diffusion Tensor Imaging of the Spinal Canal in Quantitative Assessment of Patients with Lumbar Spinal Canal Stenosis

Study Design

Retrospective observational study.

Purpose

Lumbar spinal stenosis (LSS) has traditionally been evaluated morphologically, there is a paucity of literature on quantitative assessment of LSS. The purpose of this study was to investigate whether intraspinal diffusion tensor imaging (DTI) parameters such as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) are useful for assessing LSS.

Overview of Literature

Quantitative assessment of LSS is challenging.

Methods

Study participants comprised five healthy volunteers (mean age, 27.2 years) and 27 patients with LSS (mean age, 58.4 years) who were individually assessed using 3.0 Tesla magnetic resonance imaging. Intraspinal ADC and FA values of 10 intervertebral discs from healthy volunteers and 52 intervertebral discs from LSS patients were measured. Also, intraspinal canal area, Schizas classification (A: normal, B: mild stenosis, C: severe stenosis) and correlations with symptoms were investigated. Clinical symptoms were checked for the presence of low back pain (LBP), intermittent claudication (IMC), and bladder and bowel dysfunction (BBD).

Results

Compared to healthy individuals, LSS patients had significantly lower ADC (p<0.05) and significantly higher FA values (p<0.01). In Schizas classification, stenosis worsened from A to C. ADC values decreased significantly while FA values increased significantly in that order (p<0.05). A positive correlation was found between intraspinal canal area and ADC values (r=0.63, p<0.01) and a negative correlation between intraspinal canal area and FA values (p=−0.61, p<0.01). No correlations were noted between LBP and ADC or FA values. On the other hand, ADC values were significantly lower (p<0.05) and FA values were significantly higher (p<0.05) in patients with IMC or BBD.

Conclusions

Intraspinal DTI parameters such as ADC and FA values were associated with the Schizas classification, intraspinal canal area, and clinical symptoms, suggesting that ADC and FA may be useful for quantitative assessment of LSS.

Evaluating Spinal Canal Lesions Using Apparent Diffusion Coefficient Maps with Diffusion-Weighted Imaging

STUDY DESIGN

Observational study.

PURPOSE

To evaluate healthy volunteers and patients with spinal canal lesions using apparent diffusion coefficient (ADC) maps with diffusion-weighted imaging.

OVERVIEW OF LITERATURE

Decompression surgery for lumbar spinal stenosis (LSS) is selected on the basis of subjective assessment and cross-sectional magnetic resonance imaging (MRI). However, there is no objective standard for this procedure.

METHODS

We performed 3T MRI in 10 healthy volunteers and 13 patients with LSS. The ADC values in the spinal canal were evaluated at 46 vertebrae (L4/5 and L5/S1 for each participant), and the reduced and conventional fields of view were compared.

RESULTS

The ADC values were 2.72±0.12 at L4/5 in healthy volunteers, 2.76±0.19 at L5/S1 in healthy volunteers, 1.77±0.58 at L4/5 in patients with LSS, and 2.35±0.29 at L5/S1 in patients with LSS. The ADC value at L4/5 in patients with LSS was significantly lower than that at L5/S1 in patients with LSS and that at L4/5 and L5/S1 in healthy volunteers (p <0.05). With an ADC cutoff value of 2.46 to identify LSS, this approach provided an area under the curve of 0.81, sensitivity of 0.92, and specificity of 0.76 (p <0.05).

CONCLUSIONS

Preoperative examination using ADC maps permits visualization and quantification of spinal canal lesions, thus proving the utility of ADC maps in the selection of decompression surgery for LSS.

Source directivity approximation for finite-difference time-domain simulation by estimating initial value

In order to incorporate a directive sound source into acoustic simulation using the finite-difference time-domain method (FDTD), this paper proposes an optimization-based method to estimate the initial value which approximates a desired directional pattern after propagation. The proposed method explicitly considers a discretized FDTD scheme and optimizes the initial value directly in the time domain so that every effect of the discretization error of FDTD, including numerical dispersion, is taken into account. It is also able to consider a frequency-wise directivity by integrating the Fourier transform into the optimization procedure, even though the estimated result is defined in the time domain. After the optimization, the obtained result can be utilized in any acoustic simulation based on the same FDTD scheme without modification because the result is represented as the initial value to be propagated and no additional procedure is required.

Platelet-rich plasma enhances bone union in posterolateral lumbar fusion: A prospective randomized controlled trial

BACKGROUND CONTEXT

Platelet-rich plasma (PRP) accelerates bone union in vivo in a rodent model of spinal fusion surgery. However, PRP's effect on bone union after spinal surgery remains unclear.

PURPOSE

The objective of this study was to evaluate the efficacy of PRP after posterolateral lumbar fusion (PLF) surgery.

STUDY DESIGN/SETTING

Single-center prospective randomized controlled clinical trial with 2-year follow-up.

PATIENT SAMPLE

The patient sample included a total 62 patients (31 patients in the PRP group or 31 patients in the control group).

OUTCOME MEASURES

The outcome measures included the bone fusion rate, the area of bone fusion mass, the duration of bone fusion, and the clinical score using the visual analog scale (VAS).

MATERIALS AND METHODS

We randomized 62 patients who underwent one- or two-level instrumented PLF for lumbar degenerative spondylosis with instability to either the PRP (31 patients) or the control (31 patients) groups. Platelet-rich plasma-treated patients underwent surgery using an autograft bone chip (local bone), and PRP was prepared from patient blood samples immediately before surgery; patients from the control group underwent PLF without PRP treatment. We assessed platelet counts and growth factor concentrations in PRP prepared immediately before surgery. The duration of bone union, the postoperative bone fusion rate, and the area of fusion mass were assessed using plain radiography every 3 months after surgery and by computed tomography at 12 or 24 months. The duration of bone fusion and the clinical scores for low back pain, leg pain, and leg numbness before and 3, 6, 12, and 24 months after surgery were evaluated using VAS.

RESULTS

Data from 50 patients with complete data were included. The bone union rate at the final follow-up was significantly higher in the PRP group (94%) than in the control group (74%) (p=.002). The area of fusion mass was significantly higher in the PRP group (572 mm²) than in the control group (367 mm²) (p=.02). The mean period necessary for union was 7.8 months in the PRP group and 9.8 months in the control group (p=.013). In the PRP, the platelet count was 7.7 times higher and the growth factor concentrations were 50 times higher than those found in plasma (p<.05). There was no significant difference in low back pain, leg pain, and leg numbness in either group at any time evaluated (p>.05).

CONCLUSIONS

Patients treated with PRP showed a higher fusion rate, greater fusion mass, and more rapid bone union after spinal fusion surgery than patients not treated with PRP.

Optical visualization of a fluid flow via the temperature controlling method

In this Letter, a visualization method of a fluid flow through temperature control is proposed. The proposed method enables us to visualize an invisible fluid flow by controlling the temperature so that its visibility can be easily adjusted. Such ability of adjusting appearance is effective for visualizing the phenomena consisting of multiple physical processes. In order to verify the validity of the proposed method, the measurement experiment of visualization of both flow and sound in air using parallel phase-shifting interferometry, which is a similar condition to the previous research [Opt. Lett.43, 991 (2018)OPLEDP0146-959210.1364/OL.43.000991], was conducted.

Time-directional filtering of wrapped phase for observing transient phenomena with parallel phase-shifting interferometry

Recent development of parallel phase-shifting interferometry (PPSI) enables accurate measurement of time-varying phase maps. By combining a high-speed camera with PPSI, it became possible to observe not only time-varying but also fast phenomena including fluid flow and sound in air. In such observation, one has to remove static phase (time-invariant or slowly-varying phase unrelated to the phenomena of interest) from the observed phase maps. Ordinarily, a signal processing method for eliminating the static phase is utilized after phase unwrapping to avoid the 2π discontinuity which can be a source of error. In this paper, it is shown that such phase unwrapping is not necessary for the high-speed observation, and a time-directional filtering method is proposed for removing the static phase directly from the wrapped phase without performing phase unwrapping. In addition, experimental results of simultaneously visualizing flow and sound with 42 000 fps are shown to illustrate how the time-directional filtering changes the appearance. A MATLAB code is included within the paper (also in https://goo.gl/N4wzdp) for aiding the understanding of the proposed method.

Simultaneous imaging of flow and sound using high-speed parallel phase-shifting interferometry

In this Letter, simultaneous imaging of flow and sound by using parallel phase-shifting interferometry and a high-speed polarization camera is proposed. The proposed method enables the visualization of flow and sound simultaneously by using the following two factors: (i) injection of the gas, whose density is different from the surrounding air, makes the flow visible to interferometry, and (ii) time-directional processing is applied for extracting the small-amplitude sound wave from the high-speed flow video. An experiment with a frame rate of 42,000 frames per second for visualizing the flow and sound emitted from a whistle was conducted. By applying time-directional processing to the obtained video, both flow emitted from the slit of the whistle and a spherical sound wave of 8.7 kHz were successively captured.

Insulin degludec overdose may lead to long-lasting hypoglycaemia through its markedly prolonged half-life

BACKGROUND

Overdose of insulin often causes long-lasting severe hypoglycaemia. Insulin degludec has the longest duration of action among the available insulin products; thus, an overdose of insulin degludec can lead to long-lasting hypoglycaemia. In the present paper, we report the case of a woman with long-lasting hypoglycaemia attributable to insulin degludec overdose and markedly prolonged insulin degludec half-life.

CASE REPORT

A 64-year-old woman with Type 2 diabetes receiving insulin therapy was taken to an emergency department because of disturbed consciousness 21 h after self-injection of 300 units of insulin degludec (4.34 units/kg). Her plasma glucose level was 2.3 mmol/l. She received repeated intravenous boluses of dextrose for 43 h with continuous intravenous dextrose infusion, but no improvement in long-lasting hypoglycaemia or consciousness was observed. Considering the possibility of adrenal insufficiency, intravenous dexamethasone was administered, and her plasma glucose levels subsequently remained above 5.5 mmol/l without intravenous dextrose boluses. She gradually regained consciousness. A total of 34 h after the overdose, her plasma immunoreactive insulin levels were markedly increased and then gradually declined over ~400 h. The insulin degludec half-life was 40.76 h.

CONCLUSION

Although the reported half-life of insulin degludec in the body is ~25 h when administered in standard doses (0.4-0.8 units/kg), no study has investigated its half-life after overdose. In the present case, the half-life of insulin degludec was ~1.6 times longer than that observed with standard doses, probably leading to long-lasting hypoglycaemia. Physicians should be aware of the possibility of unexpected long-lasting severe hypoglycaemia resulting from insulin degludec overdose.

Vascular endothelial growth factor in degenerating intervertebral discs of rat caudal vertebrae

Introduction

Discogenic back pain remains poorly understood with respect to etiopathogenesis, despite being a considerable burden. We sought to examine the expression of vascular endothelial growth factor in injured intervertebral discs in rat caudal vertebrae.

Methods

Forty-eight male Sprague Dawley rats were assigned to 2 groups according to disc puncture injury: puncture (n = 32) or non-puncture (n = 16). Disc puncture was performed percutaneously such that the incision would be in the primary plane of motion for the coccygeal discs 5-6, 6-7, and 7-8. A 26-gauge needle was used to puncture each disc 10 times. Punctured discs were examined histologically by hematoxylin and eosin staining at 1, 7, 14, and 28 days post-injury.

Results

Vascular endothelial growth factor was localized immunohistochemically, and determined quantitatively using an enzyme-linked immunosorbent assay. Peak inflammation occurred on the 7th day post-injury, but tissue degeneration continued until day 28. Local expression of vascular endothelial growth factor tended to be highest in the annulus fibrosus on the 7th and 14th days after puncture injury. The level of vascular endothelial growth factor was highest 1-day post-injury, and then gradually decreased thereafter. Furthermore, vascular endothelial growth factor levels in the puncture group were significantly higher than those in the non-puncture control group (p < 0.05).

Conclusions

We found increased expression of the inflammatory cytokine vascular endothelial growth factor in injured intervertebral discs, suggesting that vascular endothelial growth factor may be clinically important in discogenic back pain.

Recent advances in magnetic resonance neuroimaging of lumbar nerve to clinical applications: A review of clinical studies utilizing Diffusion Tensor Imaging and Diffusion-weighted magnetic resonance neurography

Much progress has been made in neuroimaging with Magnetic Resonance neurography and Diffusion Tensor Imaging (DTI) owing to higher magnetic fields and improvements in pulse sequence technology. Reports on lumbar nerve DTI have also increased considerably. Many studies have shown that the use of DTI in lumbar nerve lesions, such as lumbar foraminal stenosis and lumbar disc herniation, makes it possible to capture images of interruptions of tractography at stenotic sties, enabling the diagnosis of stenosis. DTI can also reveal significant decreases in fractional anisotropy (FA) with significant increases in apparent diffusion coefficient (ADC) values in compression lesions. FA values have higher accuracy than ADC values. Furthermore, strong correlations exist between FA values and indications of neurological severity, including the Japanese Orthopedic Association (JOA) score, the Oswestry Disability Index (ODI), and the Roland-Morris Disability Questionnaire (RDQ) in patients with lumbar disc herniation-induced radiculopathy. Most lumbar DTI has become 3T; 3T MRI has made it possible to take high-resolution DTI measurements in a short period of time. However, increased motion artifacts in the magnetic susceptibility effect lead to signal irregularities and image distortion. In the future, high-resolution DTI with reduced field-of-view may become useful in clinical applications, since visualization of nerve lesions and quantification of DTI parameters could allow more accurate diagnoses of lumbar nerve dysfunctions. Future translational studies will be necessary to successfully bring MR neuroimaging of lumbar nerve into clinical use.

Visualization of lumbar nerves using reduced field of view diffusion tensor imaging in healthy volunteers and patients with degenerative lumbar disorders

OBJECTIVE

We investigated high resolution diffusion tensor imaging (DTI) of lumbar nerves with reduced field of view (rFOV) using 3 T MRI.

METHODS

DTI measured with rFOV was compared with conventional FOV (cFOV) 3.0 T MRI in 5 healthy volunteers and 10 patients with degenerative lumbar disorders. The intracanal, foramina and extraforamina of the L5 nerve were established as the regions of interest and fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) values were measured. Image quality for tractography and FA maps and ADC maps, interindividual and intraindividual reliability of FA and ADC, and signal-to-noise (SNR) were studied.

RESULTS

Both of image qualities with tractography, FA map and ADC map showed that lumbar nerves were more clearly imaged with the rFOV. Intraindividual reliability was higher with rFOV compared with the conventional method for ADC values, while interindividual reliability was higher for both FA values and ADC values with the rFOV method over the conventional method (p < 0.05). Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal (p < 0.05).

CONCLUSION

rFOV enabled clearer imaging of the lumbar nerve, allowing for more accurate measurement of FA and ADC values. Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal. To our knowledge, this research showed for the first time the usefulness of rFOV in patients with degenerative lumbar disorders. High resolution DTI using rFOV may become useful in clinical applications because visualization of nerve entrapments and quantification of DTI parameters may allow more accurate diagnoses of lumbar nerve dysfunction. Advances in knowledge: Compared with traditional methods, rFOV allows for clear imaging of the lumbar nerve and enables accurate measurements of the FA and ADC values. High-resolution DTI with rFOV may be used to visualize nerve entrapments and allow for more accurate diagnosis of DTI parameter quantification with opportunities for clinical applications.

Efficacy of nerve growth factor antibody in a knee osteoarthritis pain model in mice

Background

Nerve growth factor (NGF) is not only an important factor in nerve growth but also a major contributor to the production of inflammation. It has been reported that inhibiting NGF could reduce several types of pain in several animal models. Here, we aimed to clarify the efficacy of NGF antibody in a knee osteoarthritis (OA) pain model in mice.

Method

Six-week-old male C57BR/J mice were used (n = 30). Ten mice comprised the control group, which received saline injection into the right knee joints; the other 20 mice comprised the experimental group, which received monoiodoacetate (MIA) injection into the right knee joints. Three weeks after surgery, the 20 experimental mice were randomly placed into treatment groups which received either sterile saline (non-treat group: 10 mg/kg, i.p.) or an anti-NGF antibody (anti-NGF group: 10 mg/kg, i.p.). Simultaneously, all mice received fluorogold (FG) retrograde neurotracer injection into their right joints. In a behavioral study, we evaluated gait using the CatWalk quantitative gait analysis system before surgery, 3 weeks after surgery (before treatment), 4 weeks after surgery (one week after surgery), and 5 weeks after surgery (2 weeks after surgery). In immunohistochemical analysis, the right dorsal root ganglia (DRGs) from the L4–L6 levels were resected 5 weeks after surgery (2 weeks after surgery). They were immunostained for calcitonin gene-related peptide (CGRP), and the number of FG-labeled or CGRP-immunoreactive (IR) DRG neurons was counted.

Results

On gait analysis using the CatWalk system, duty cycle, swing speed, and print area were decreased in non-treat group compared with those in control group and improved in the anti-NGF group compared with those in non-treat group. CGRP expression in DRGs was up-regulated in non-treat group compared with that in control group and suppressed in the anti-NGF group compared with that in non-treat group (both p < 0.05).

Conclusions

MIA injection into the knee joint induced gait impairment and the up-regulation of CGRP in DRG neurons in a knee OA pain model in mice. Intraperitoneal injection of anti-NGF antibody suppressed this impairment of gait and up-regulation of CGRP in DRG neurons. These finding suggest that anti-NGF therapy might be valuable in the treatment of OA pain in the knee.

Anatomical evaluation of lumbar nerves using diffusion tensor imaging and implications of lateral decubitus for lateral transpsoas approach

PURPOSE

Recently, lateral interbody fusion (LIF) has become more prevalent, and evaluation of lumbar nerves has taken on new importance. We report on the assessment of anatomical relationships between lumbar nerves and vertebral bodies using diffusion tensor imaging (DTI).

METHODS

Fifty patients with degenerative lumbar disease and ten healthy subjects underwent DTI. In patients with lumbar degenerative disease, we studied nerve courses with patients in the supine positions and with hips flexed. In healthy subjects, we evaluated nerve courses in three different positions: supine with hips flexed (the standard position for MRI); supine with hips extended; and the right lateral decubitus position with hips flexed. In conjunction with tractography from L3 to L5 using T2-weighted sagittal imaging, the vertebral body anteroposterior span was divided into four equally wide zones, with six total zones defined, including an anterior and a posterior zone (zone A, zones 1-4, zone P). We used this to characterize nerve courses at disc levels L3/4, L4/5, and L5/S1.

RESULTS

In patients with degenerative lumbar disease, in the supine position with hips flexed, all lumbar nerve roots were located posterior to the vertebral body centers in L3/4 and L4/5. In healthy individuals, the L3/4 nerve courses were displaced forward in hips extended compared with the standard position, whereas in the lateral decubitus position, the L4/5 and L5/S nerve courses were displaced posteriorly compared with the standard position.

CONCLUSIONS

The L3/4 and L4/5 nerve roots are located posterior to the vertebral body center. These were found to be offset to the rear when the hip is flexed or the lateral decubitus position is assumed. The present study is the first to elucidate changes in the course of the lumbar nerves as this varies by position. The lateral decubitus position or the position supine with hips flexed may be useful for avoiding nerve damage in a direct lateral transpsoas approach. Preoperative DTI seems to be useful in evaluating the lumbar nerve course as it relates anatomically to the vertebral body.

Simple, flexible, and accurate phase retrieval method for generalized phase-shifting interferometry

This paper presents a non-iterative phase retrieval method from randomly phase-shifted fringe images. By combining the hyperaccurate least squares ellipse fitting method with the subspace method (usually called the principal component analysis), a fast and accurate phase retrieval algorithm is realized. The proposed method is simple, flexible, and accurate. It can be easily coded without iteration, initial guess, or tuning parameter. Its flexibility comes from the fact that totally random phase-shifting steps and any number of fringe images greater than two are acceptable without any specific treatment. Finally, it is accurate because the hyperaccurate least squares method and the modified subspace method enable phase retrieval with a small error as shown by the simulations. A MATLAB code, which is used in the experimental section, is provided within the paper to demonstrate its simplicity and easiness.

Single Intradiscal Administration of the Tumor Necrosis Factor-Alpha Inhibitor, Etanercept, for Patients with Discogenic Low Back Pain

OBJECTIVE

To examine the analgesic effect of intradiscal administration of a tumor necrosis factor-αα (TNF-α) inhibitor in patients with discogenic low back pain (LBP).

DESIGN

Prospective, randomized study.

SETTING

Department of Orthopaedic Surgery, Chiba (Japan) University Hospital.

SUBJECTS

Seventy-seven patients diagnosed with discogenic LBP.

METHODS

Discogenic LBP patients were randomly assigned to the etanercept (n = 38; bupivacaine [2 mL] with etanercept [10 mg]) or control (n = 39; bupivacaine [2 mL]) groups. Patients received a single intradiscal injection. Numerical rating scale (NRS) scores for LBP at baseline, 1 day, and 1, 2, 4, and 8 weeks after the injection were recorded. The Oswestry disability index (ODI) scores at baseline and at 4 and 8 weeks after injection were evaluated. Postinjection complications were recorded and evaluated.

RESULTS

In the etanercept group, the NRS scores were significantly lower than in the control group at every time point after the injection for 8 weeks (P < 0.05). Similarly, 4 weeks after the injection, the ODI score was lower in the etanercept group than in the control group (P < 0.05). However, the ODI scores were not significantly different at 8 weeks. Complications were not observed.

CONCLUSIONS

Single intradiscal administration of a TNF-α inhibitor can alleviate intractable discogenic LBP for up to 8 weeks. TNF-α may be involved in discogenic pain pathogenesis. This procedure is a novel potential treatment; longer-term effectiveness trials are required in the future.

Differences in levels of inflammatory mediators in meniscal and synovial tissue of patients with meniscal lesions

BACKGROUND

Meniscal injuries are a risk factor for osteoarthritis (OA). While a mechanical pathway between meniscal injury and OA has been described, the biological effects of inflammation on this pathway have yet to be clarified. The aim of our study was to compare levels of specific inflammatory mediators, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and nerve growth factor (NGF), in injured and uninjured meniscal tissue and related knee joint synovium.

METHODS

Tissue samples were obtained from 19 patients, 31.1 ± 13.6 years old, who underwent arthroscopic partial meniscectomy. For analysis, tissue samples were categorized into the following groups: injured meniscal site (IM), non-injured meniscal site (NIM), synovium 'nearest' the lesion (NS), and synovium from the opposite knee compartment, 'farthest' synovium (FS). Levels of inflammatory mediators were determined using enzyme-linked immunosorbent assay and between-group differences (IM and NIM; NS and FS) were evaluated using the Wilcoxon signed-rank test. The association between pre-operative pain score and the level of each inflammatory mediator was evaluated using Spearman's correlation.

RESULTS

Higher levels of TNF-α and IL-6 were identified in the IM tissue, compared to NIM (p <0.05). IL-6 levels were also higher in the NS compared to the FS (p <0.05). There was no correlation between pre-operative pain score and level of each inflammatory mediator.

CONCLUSIONS

Our outcomes confirm a local increase in inflammatory mediator levels, in both meniscal and synovial tissue, which could contribute to development of OA. Management of these biological effects of meniscal injury might be warranted.

Improving principal component analysis based phase extraction method for phase-shifting interferometry by integrating spatial information

Phase extraction methods based on the principal component analysis (PCA) can extract objective phase from phase-shifted fringes without any prior knowledge about their shift steps. Although it is fast and easy to implement, many fringe images are needed for extracting the phase accurately from noisy fringes. In this paper, a simple extension of the PCA method for reducing extraction error is proposed. It can effectively reduce influence from random noise, while most of the advantages of the PCA method is inherited because it only modifies the construction process of the data matrix from fringes. Although it takes more time because size of the data matrix to be decomposed is larger, computational time of the proposed method is shown to be reasonably fast by using the iterative singular value decomposition algorithm. Numerical experiments confirmed that the proposed method can reduce extraction error even when the number of interferograms is small.

Detection of Francisella tularensis and analysis of bacterial growth in ticks in Japan

Francisella tularensis is distributed in the Northern hemisphere and it is the bacterial agent responsible for tularaemia, a zoonotic disease. We collected 4 527 samples of DNA from ticks in Japan, which were then analysed by real-time PCR and nested PCR. Francisella DNA was detected by real-time PCR in 2·15% (45/2 093) of Ixodes ovatus, 0·66% (14/2 107) of I. persulcatus, 8·22% (6/73) of I. monospinosus and 0·72% (1/138) of Haemaphysalis flava specimens. Finally, Francisella DNA was detected by nested PCR in 42 and five samples I. ovatus and I. persulcatus, respectively, which were positive according to real-time PCR. Phylogenetic analysis showed that the sequence from I. ovatus and I. persulcatus were clustered with F. tularensis type B strains distributed in Eurasia. Microinjected live F. tularensis persisted in ticks, whereas heat-killed F. tularensis decreased. Microinjected F. tularensis hlyD mutant decreased in ticks significantly compared to parent strain, thereby suggesting that HlyD in F. tularensis contributes to the adaptation or survive of bacterial infection in ticks.

SIGNIFICANCE AND IMPACTS OF THE STUDY

Francisella tularensis has been detected in ticks, suggesting that it is a tick-borne pathogen. However, F. tularensis has not been detected in ticks in Japan since 1991. In this study, we performed a large-scale analysis of DNA isolated from ticks in Japan and detected F. tularensis by real-time polymerase chain reaction (PCR) and nested PCR. We found that F. tularensis could survive in ticks based on an experimental tick-infection model. We also identified a bacterial factor that contributes to survival in ticks. Our results suggest that ticks are candidate vectors that mediate F. tularensis infection in Japan.

Compensation of fringe distortion for phase-shifting three-dimensional shape measurement by inverse map estimation

For three-dimensional shape measurement, phase-shifting techniques are widely used to recover the objective phase containing height information from images of projected fringes. Although such techniques can provide an accurate result in theory, there might be considerable error in practice. One main cause of such an error is distortion of fringes due to nonlinear responses of a measurement system. In this paper, a postprocessing method for compensating distortion is proposed. Compared to other compensation methods, the proposed method is flexible in two senses: (1) no specific model of nonlinearity (such as the gamma model) is needed, and (2) no special calibration data are needed (only the observed image of the fringe is required). Experiments using simulated and real data confirmed that the proposed method can compensate multiple types of nonlinearity without being concerned about the model.

Muscle injury in rats induces upregulation of inflammatory cytokines in injured muscle and calcitonin gene-related peptide in dorsal root ganglia innervating the injured muscle

Introduction: In this study we evaluated the relationships among the behavioral changes after muscle injury, histological changes, changes in inflammatory cytokines in the injured muscle, and changes in the sensory nervous system innervating the muscle in rats. Methods: We established a model of muscle injury in rats using a dropped weight. Behavior was assessed using the CatWalk system. Subsequently, bilateral gastrocnemius muscles and dorsal root ganglia (DRGs) were resected. Muscles were stained with hematoxylin and eosin, and inflammatory cytokines in injured muscles were assayed. DRGs were immunostained for calcitonin gene–related peptide (CGRP). Results: Changes of behavior and upregulation of inflammatory cytokines in injured muscles subsided within 2 days of injury. Repaired tissue was observed 3 weeks after injury. However, upregulation of CGRP in DRG neurons continued for 2 weeks after injury. Conclusion: These findings may explain in part the pathological mechanism of persistent muscle pain. Muscle Nerve54: 776–782, 2016

High-speed imaging of sound using parallel phase-shifting interferometry

Sound-field imaging, the visualization of spatial and temporal distribution of acoustical properties such as sound pressure, is useful for understanding acoustical phenomena. This study investigated the use of parallel phase-shifting interferometry (PPSI) with a high-speed polarization camera for imaging a sound field, particularly high-speed imaging of propagating sound waves. The experimental results showed that the instantaneous sound field, which was generated by ultrasonic transducers driven by a pure tone of 40 kHz, was quantitatively imaged. Hence, PPSI can be used in acoustical applications requiring spatial information of sound pressure.

Convex optimization-based windowed Fourier filtering with multiple windows for wrapped-phase denoising

The windowed Fourier filtering (WFF), defined as a thresholding operation in the windowed Fourier transform (WFT) domain, is a successful method for denoising a phase map and analyzing a fringe pattern. However, it has some shortcomings, such as extremely high redundancy, which results in high computational cost, and difficulty in selecting an appropriate window size. In this paper, an extension of WFF for denoising a wrapped-phase map is proposed. It is formulated as a convex optimization problem using Gabor frames instead of WFT. Two Gabor frames with differently sized windows are used simultaneously so that the above-mentioned issues are resolved. In addition, a differential operator is combined with a Gabor frame in order to preserve discontinuity of the underlying phase map better. Some numerical experiments demonstrate that the proposed method is able to reconstruct a wrapped-phase map, even for a severely contaminated situation.

The efficacy of nerve growth factor antibody in a mouse model of neuropathic cancer pain

Neuropathic cancer pain is caused by tumors compressing the spinal nerve roots and is usually difficult to treat. The aim of current study was to determine the influence of NGF antibody on pain-related markers and behavior in a mouse model of neuropathic cancer pain. Twenty mice were used to model neuropathic cancer pain by applying murine sarcoma cells to their left sciatic nerve. Ten mice were sham operated. Two weeks after surgery, the murine sarcoma-affected mice were allocated randomly into treatment groups receiving either sterile saline (saline group) or an anti-nerve growth factor antibody (anti-NGF group). Three weeks after surgery (a week after treatment), the pain-related behavior of mice was evaluated using a CatWalk system. Subsequently, bilateral dorsal root ganglia (DRGs) from the L4–L6 levels and spinal cords at L4–L6 levels were resected. DRGs were immunostained for calcitonin gene-related peptide (CGRP) and activating transcription factor 3 (ATF-3), and spinal cords were immunostained for ionized calcium-binding adaptor molecule-1 (iba-1). Mechanical allodynia was observed in mice from the saline group and was improved in mice from the anti-NGF group. CGRP and ATF-3-immunoreactivity in DRGs and microglia expression in the spinal dorsal horn were upregulated in the saline group compared with the sham group, and they were suppressed in the anti-NGF group compared with the saline group (P<0.05). These findings suggest that anti-NGF therapy might be valuable for treating neuropathic cancer pain.

One-Year Prospective Evaluation of the Technique of Percutaneous Cortical Bone Trajectory Spondylodesis in Comparison with Percutaneous Pedicle Screw Fixation: A Preliminary Report with Technical Note

Background and Objective Cortical bone trajectory (CBT) spondylodesis is a novel screw fixation method in which screws are inserted through the pedicle in a caudal-medial to cephalad-lateral direction, providing a similar or more rigid spinal fixation compared with traditional pedicle screws. However, the traditional CBT technique requires invasive detaching and opening of the paraspinal muscle. In a small clinical prospective study we introduced a percutaneous CBT fixation technique by modifying the percutaneous pedicle screw (PPS) technique and evaluated the short-term outcome. Materials and Methods We enrolled 40 patients with lower back pain (LBP) and limb r;adicular pain with a diagnosis of spondylolisthesis who underwent transforaminal lumbar interbody fusion surgery. The patients were divided into two groups according to screw trajectory: the percutaneous CBT (pCBT) and the traditional PPS arms (20 patients in each). A consecutive group of 20 patients underwent traditional PPS, and the other underwent pCBT; dorsal spondylodesis was combined with transforaminal lumbar interbody fusion (TLIF) in both groups. Perioperative data such as operative time, blood loss, duration of fluoroscopy, and total incision length were investigated. Postoperative outcomes were evaluated using the visual analog scale (VAS) for LBP and leg pain at baseline, 1, 6, and 12 months. A p value < 0.05 was considered statistically significant. Results We observed no significant disadvantages in pCBT patients in perioperative and postoperative data compared with the PPS group. There were no complications. The pCBT patients showed a significantly shorter total incision length (p < 0.01) with a significantly shorter duration of fluoroscopy (p < 0.05). The postoperative VAS score was significantly improved in the pCBT group, especially 6 months after the surgery (p < 0.05). Conclusion The pCBT spondylodesis provided an outcome comparable with PPS fixation with a tendency for improvement 1 year postsurgery. This technique can be used in appropriate cases, combined with lumbar interbody fusion.

The diagnosis of double-crush lesion in the L5 lumbar nerve using diffusion tensor imaging

BACKGROUND CONTEXT

A double-crush lesion is a condition in which the lumbar nerve is compressed both medially and laterally in the spinal canal, where diagnosis can be very difficult, and is a factor leading to poor surgical success rates.

PURPOSE

Diffusion tensor imaging (DTI) was used to determine DTI parameter fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) in both intraspinal column lesions alone and in double-crush lesions.

STUDY DESIGN

This study used a prospective study.

PATIENT SAMPLE

Of the 56 cases (mean age: 72.2 years) that underwent laminectomy for lumbar spinal stenosis at our clinic between April 2013 to March, 2015, 10 cases with L5 radiculopathy caused by L4-L5 stenosis (Intraspinal stenosis group (Group I); mean age: 74.7 years), and 5 cases with persistent symptoms caused by L5 foraminal stenosis despite L4-L5 decompression surgery (Double-crush group (Group D); mean age: 77.6 years) were targeted. One patient in Group D was diagnosed through microendoscopic intrapedicular partial pediculotomy and the remaining four cases by nerve root infiltration. Five healthy cases (mean age: 54 years) were studied as controls.

OUTCOME MEASURES

Intraspinal zone (Iz), nerve root (N), and extraforaminal zone (Ez) were established as the regions of interest, and the L5 nerve FA and ADC values were determined on the affected side.

METHODS

Diffusion tensor imaging was performed prospectively by 1.5T magnetic resonance imaging before surgery, and DTI parameters of L5 nerve were evaluated in all patients and healthy volunteers. Student t test was used for group comparisons, and a p<.05 was considered statistically significant.

RESULTS

Fractional anisotropy values (Iz, N, Ez) were 0.415, 0.448, and 0.517, respectively, increasing as sites became more distal. Group I values were 0.335, 0.393, and 0.484, and Group D values were 0.296, 0.367, and 0.360. Compared with the healthy volunteers, Group D had significantly lower Iz (p<.05) and Ez (p<.001) values, while Group I had significantly lower Iz (p<.05) values. In Group D, Ez FA values were significantly lower (p<.001) than in Group I. Apparent diffusion coefficient values (Iz, N, Ez) in the healthy control group were 1.270 mm2/s, 1.151 mm2/s, and 0.937 mm2/s with values decreasing as sites grew distal. In Group I, the ADC values were 1.406 mm2/s, 1.184 mm2/s, and 1.001 mm2/s, while in Group D they were 1.551 mm2/s, 1.412 mm2/s, and 1.329 mm2/s. Compared with the healthy volunteers, Iz (p<.05) and Ez (p<.05) values were significantly higher in Group D. The N (p<.01) and Ez (p<.001) ADC values were significantly higher in Group D than in Group I.

CONCLUSIONS

Depending on where the nerve was compressed, changes in DTI parameters revealed nerve damage (low FA values and increased ADC) in the intraspinal canal in the Intraspinal Group, and over a widespread area in the Double-crush Group spanning the medial to lateral spinal canal. Our research suggests that in cases where double crush is suspected before surgery, failed back surgery syndrome may be prevented by evaluating DTI images.

Effect of administration of antibodies against nerve growth factor in a rat model of muscle injury

INTRODUCTION

Although muscle injury is a common source of pain, the mechanism causing such pain is not completely known. We have previously reported nerve growth factor (NGF) as a proinflammatory mediator involved in acute pain, and clinical trials have shown the effectiveness of anti-NGF antibodies for management of low back pain. Here, we aim to examine the effects of anti-NGF antibodies on muscle-derived pain by studying their effects on sensory innervation in a rat muscle injury model.

METHODS

A nervous system tracer, Fluoro-Gold, was applied to both gastrocnemius muscles of 24 male Sprague Dawley rats to stain the sensory nerves. Then, the drop-mass method was used to damage the right gastrocnemius muscle of the posterior limb. Anti-NGF antibodies (50μL) were injected into the injured muscles in 12 rats. Tissues were evaluated 1, 3, and 7 days post-injury by performing haematoxylin-and-eosin (HE) staining. The percentage of the total number of FG-positive cells that were also positive for a pain-related neuropeptide, calcitonin gene-related peptide (CGRP), was determined for the bilateral dorsal root ganglia from L1 to L6 7 days post-injury.

RESULTS

HE staining showed active inflammation, indicated by increased basophil and eosinophil accumulation, at the injury site 1 and 3 days post-injury, as well as scar tissue formation 7 days post-injury. Injection of anti-NGF reduced muscle necrosis 1 and 3 days post-injury, and resulted in replacement of granulation tissue and muscle fibre regeneration 7 days post-injury. Anti-NGF also significantly inhibited CGRP among FG-positive cells (treatment group 38.2%, control group 49.6%; P<0.05).

DISCUSSION

This study found active inflammation induced by NGF, which may contribute to pain after muscle injury. Anti-NGF antibodies successfully suppressed the pain mediator NGF and inhibited inflammation, suggesting NGF as a target for control in pain management.

Diffusion tensor imaging of radiculopathy in patients with lumbar disc herniation

Aims

The aim of this study was to evaluate the time course of changes in parameters of diffusion tensor imaging (DTI) such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in patients with symptomatic lumbar disc herniation. We also investigated the correlation between the severity of neurological symptoms and these parameters.

Patients and Methods

A total of 13 patients with unilateral radiculopathy due to herniation of a lumbar disc were investigated with DTI on a 1.5T MR scanner and underwent micro discectomy. There were nine men and four women, with a median age of 55.5 years (19 to 79). The changes in the mean FA and ADC values and the correlation between these changes and the severity of the neurological symptoms were investigated before and at six months after surgery.

Results

The mean FA values were significantly lower (p = 0.0005) and mean ADC values were significantly higher (p = 0.0115) in compressed nerves than in intact nerves. Although the FA values increased significantly at six months after surgical treatment (p = 0.020), the ADC values decreased but not significantly (p = 0.498). There were strong correlations between the DTI parameters such as the FA value and the severity of the neurological symptoms as assessed using the Japanese Orthopaedic Association (JOA) score and the Roland-Morris Disability Questionnaire (RDQ).

Conclusion

This preliminary study suggests that it may be possible to use DTI to diagnose, quantitatively evaluate and follow-up patients with lumbar nerve entrapment. Take home message: DTI is a potential tool for functional diagnosis of lumbar nerve damage. Cite this article: Bone Joint J 2016;98-B:387–94.

Decreased Defibrillation Threshold and Minimized Myocardial Damage With Left Axilla Implantable Cardioverter Defibrillator Implantation

BACKGROUND

To reduce myocardial damage caused by implantable cardioverter defibrillator (ICD) shock, the left axilla was studied as an alternative pulse generator implantation site, and compared with the traditional implantation site, the left anterior chest.

METHODS AND RESULTS

Computer simulation was used to study the defibrillation conduction pattern and estimate the simulated defibrillation threshold (DFT) and myocardial damage when pulse generators were placed in the left axilla and left anterior chest, respectively; pulse generators were also newly implanted in the left axilla (n=30) and anterior chest (n=40) to compare the corresponding DFT. On simulation, when ICD generators were implanted in the left axilla, compared with the left anterior chest, the whole heart may be defibrillated with a lower defibrillation energy (left axilla 6.4 J vs. left anterior chest 12.0 J) and thus the proportion of cardiac myocardial damage may be reduced (2.1 vs. 4.2%). Clinically, ventricular fibrillation was successfully terminated with a defibrillation output ≤5 J in 86.7% (26/30) of the left axillary group, and in 27.5% (11/40) of the left anterior group (P<0.001).

CONCLUSIONS

Clinically and theoretically, the left axilla was shown to be an improved ICD implantation site that may reduce DFT and lessen myocardial damage due to shock. Lower DFT also facilitates less myocardial damage, as a result of the lower shock required.

Effective treatment of post-spinal fusion methicillin-resistant Staphylococcus aureus vertebral osteomyelitis with linezolid in a renal-transplant patient

Background

Methicillin-resistant Staphylococcus aureus (MRSA)-caused pyogenic spondylitis is a serious complication associated with lumbar fusion surgery. Often, anti-MRSA drugs are not used properly or patients discontinue drug use because of side effects including renal failure.

Case presentation

We report a case at our hospital of a 54-year-old male renal-transplant patient who developed MRSA vertebral osteomyelitis after spinal fusion and was treated effectively with linezolid. After diagnosis of post–fusion surgery osteomyelitis, we conducted emergency flushing and debridement and began linezolid treatment (1200 mg/day, divided) immediately after the surgery. The level of C-reactive protein gradually decreased and became negative 4 weeks after the initiation of linezolid treatment. Serum creatinine level was approximately 1.3 mg/dL throughout the treatment period, indicating no deterioration in renal function.

Conclusion

These results suggest that early flushing and debridement together with linezolid administration is an effective treatment for MRSA vertebral osteomyelitis in renal-transplant patients.

Modified Open-Door Laminoplasty Using a Ceramic Spacer and Suture Fixation for Cervical Myelopathy

PURPOSE

To introduce a new simple technique using suture anchors and ceramic spacers to stabilize the elevated laminae in open-door cervical laminoplasty. Although ceramic spacers were placed in the opened laminae and fixed with nylon threads in this series, it was occasionally difficult to fix the nylon threads to the lateral mass.

MATERIALS AND METHODS

Study 1: A preliminary study was conducted using a suture anchor system. Sixteen consecutive patients who underwent surgery for cervical myelopathy were prospectively examined. Study 2: The second study was performed prospectively to evaluate the feasibility of this new technique based on the result of the preliminary study. Clinical outcomes were examined in 45 consecutive patients [cervical spondylotic myelopathy (CSM)] and 43 consecutive patients (OPLL). The Japanese Orthopedic Association scoring system (JOA score), axial neck pain, and radiological findings were analyzed.

RESULTS

1) In one case, re-operation was necessary due to dislodgement of the ceramic spacer following rupture of the thread. 2) In all patients, postoperative CT scans showed that the anchors were securely inserted into the bone. In the CSM group, the average JOA score improved from 9.5 points preoperatively to 13.3 at follow-up (recovery 51%). In the OPLL group, the average JOA score improved from 10.1 (5-14) points preoperatively to 14.4 (11-16) at follow-up (recovery 62%). There were no serious complications.

CONCLUSION

The use of the suture anchor system made it unnecessary to create a hole in the lateral mass and enabled reliable and faster fixation of the HA spacers in open-door laminoplasty.

Interleukin-6 and interleukin-6 receptor expression, localization, and involvement in pain-sensing neuron activation in a mouse intervertebral disc injury model

The pathological mechanism of intractable low back pain is unclear. However, intervertebral disc (IVD) degeneration is a primary cause of low back pain, and pain-related mediators, such as interleukin-6 (IL-6), have been correlated with discogenic pain. The objective of this study is to elucidate the mechanism of local IL-6 and IL-6 receptor (IL-6R) expression after IVD injury as well as determine the involvement of IL-6/IL-6 signaling in discogenic pain. To do this, quantitative and immunohistological analyses in a mouse model of IVD injury were performed. Firstly, we measured the local expression levels of IL-6 and IL-6R in IVDs by enzyme-linked immunosorbent assay (ELISA). Secondly, we immunohistochemically confirmed their localization in injured IVDs. Lastly, we evaluated the effects of intradiscal injection of an IL-6 inhibitor by evaluating pain-related protein, calcitonin gene-related peptide (CGRP), expression in dorsal root ganglia (DRG) neurons that innervate IVDs. Injured IVDs showed increased production of IL-6 and IL-6R. IL-6 and IL-6R expression in the injured IVD were predominantly localized in the annulus fibrosus and endplate, and intradiscal injection of the IL-6 inhibitor suppressed CGRP expression in the DRG neurons. These results show that IL-6 and IL-6R expression levels are responsive to IVD injury and that inhibition of IL-6/IL-6R signaling may be a promising analgesic treatment for degenerative disc diseases.

Decreased calcitonin gene-related peptide expression in the dorsal root ganglia of TNF-deficient mice in a monoiodoacetate-induced knee osteoarthritis model

BACKGROUND

The detailed mechanisms of knee osteoarthritis (OA) pain have not been clarified, but involvement of inflammatory cytokines such as tumor necrosis factor-alpha (TNF) has been suggested. The present study aimed to investigate the more detailed neurological involvement of TNF in joint pain using a TNF-knockout mouse OA model.

METHODS

The right knees of twelve-week-old C57BL/6J wild and TNF-deficient knockout (TNF-ko) mice (n=15, each group) were given a single intra-articular injection of 10 µg monoiodoacetate in 10 mL sterile saline. The left knees were only punctured as the control. Evaluations were performed immediately after the injection (baseline) and at 7, 14, and 28 days after the injection with a subsequent intra-articular injection of neurotracer into both knees. The animals were evaluated for immunofluorescence of the lumbar dorsal root ganglia (DRG) innervating the knee joints. The injected knees were observed macroscopically and mouse pain-related behaviors were scored.

RESULTS

Macroscopic observation showed similar knee OA development in both wild and TNF-ko mice. Calcitonin gene-related peptide (CGRP, a neuropeptide identified as a inflammatory pain-related biomarker) was significantly increased in DRG neurons innervating OA-induced knee joints with significantly less CGRP expression in TNF-ko animals. Pain-related behavior scoring showed a significant increase in pain in OA-induced joints, but there was no significant difference in pain observed between the wild and TNF-ko mice.

CONCLUSIONS

The result of the present study indicates the possible association of TNF-alpha in OA pain but not OA development.

Efficacy of Direct Injection of Etanercept into Knee Joints for Pain in Moderate and Severe Knee Osteoarthritis

PURPOSE

Osteoarthritic (OA) pain is largely considered to be inflammatory pain. However, during the last stage of knee OA, sensory nerve fibers in the knee are shown to be significantly damaged when the subchondral bone junction is destroyed, and this can induce neuropathic pain. Several authors have reported that tumor necrosis factor-α (TNFα) in a knee joint plays a crucial role in pain modulation. The purpose of the current study was to evaluate the efficacy of etanercept, a TNFα inhibitor, for pain in knee OA.

MATERIALS AND METHODS

Thirty-nine patients with knee OA and a 2-4 Kellgren-Lawrence grading were evaluated in this prospective study. Patients were divided into two groups; hyaluronic acid (HA) and etanercept injection. All patients received a single injection into the knee. Pain scores were evaluated before and 4 weeks after injection using a visual analogue scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and they were compared between the groups.

RESULTS

Before injection, VAS and WOMAC scores were not significantly different between the groups (p>0.05). Significant pain relief was found in the etanercept group at 1 and 2 weeks by VAS, and at 4 weeks by WOMAC score, compared with the HA group (p<0.05). No adverse events were observed in either group.

CONCLUSION

Direct injection of etanercept into OA knee joints was an effective treatment for pain in moderate and severe OA patients. Furthermore, this finding suggests that TNFα is one factor that induces OA pain.

Mini-Open Anterior Retroperitoneal Lumbar Interbody Fusion: Oblique Lateral Interbody Fusion for Lumbar Spinal Degeneration Disease

PURPOSE

Surgery for lumbar spinal degeneration disease is widely performed. While posterior decompression and fusion are popular, anterior lumbar interbody fusion (ALIF) is also used for treatment. Extreme lateral interbody fusion (XLIF) is commonly used for noninvasive ALIF; however, several complications, such as spinal nerve and psoas muscle injury, have been reported. In the current study, we examined the clinical efficacy and complications of oblique lateral interbody fusion (OLIF) for lumbar spinal degeneration disease.

MATERIALS AND METHODS

Thirty-five patients with degenerated spondylolisthesis, discogenic pain, and kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with or without posterior decompression, without real-time electromyography monitoring. Posterior screws were used in all patients. Visual analog scale (VAS) score and Oswestry Disability Index (ODI) were evaluated before and 6 months after surgery. Surgical complications were also evaluated.

RESULTS

Pain scores significantly improved after surgery, compared to those before surgery (p<0.05). There was no patient who underwent revision surgery. There was no spinal nerve, major vessel, peritoneal, or urinary injury. Few patients showed symptoms from psoas invasion.

CONCLUSION

OLIF surgery produced good surgical results without any major complication.

Longitudinal evaluation of local muscle conditions in a rat model of gastrocnemius muscle injury using an in vivo imaging system

This study aimed to evaluate the time course of local changes during the acute phase of gastrocnemius muscle strain, in a rat model, using an in vivo imaging system. Thirty-eight, 8-week-old Sprague-Dawley male rats were used in our study. Experimental injury of the right gastrocnemius muscle was achieved using the drop-mass method. After inducing muscle injury, a liposomally formulated indocyanine green derivative (LP-iDOPE, 7 mg/kg) was injected intraperitoneally. We evaluated the muscle injuries using in vivo imaging, histological examinations, and enzyme-linked immunosorbent assays. The fluorescence peaked approximately 18 h after the injury, and decreased thereafter. Histological examinations revealed that repair of the injured tissue occurred between 18 and 24 h after injury. Quantitative analyses for various cytokines demonstrated significant elevations of interleukin-6 and tumor necrosis factor-α at 3 and 18 h post-injury, respectively. The time course of fluorescence intensity, measured using in vivo imaging, demonstrated that the changes in cytokine levels and histopathologic characteristics were consistent. Specifically, these changes reached peaked 18 h post-injury, followed by trends toward recovery.

Diffusion tensor imaging of lumbar spinal nerve in subjects with degenerative lumbar disorders

Recently several authors have reported that diffusion tensor imaging (DTI) might provide a new understanding of sciatica. The purpose of this study was to investigate the clinical feasibility of DTI for the evaluation of lumbar spinal nerve of patients with sciatica associated with lumbar degenerative disorders. Thirty-four patients (25men, mean age63. 3years) with degenerated lumbar disease, 14 patients with lumbar spinal stenosis with foraminal stenosis, 12 with lumbar spinal stenosis without foraminal stenosis, five with lumbar disc herniation, two with discogenic low back pain, and one with spondylolysis who underwent 3.0T magnetic resonance (MR) imaging and surgical treatment were included in the present study. Fractional anisotropy (FA) was calculated from an FA map, and tractography was investigated. In asymptomatic nerves, tractography showed all L3-S1 spinal nerve roots clearly. Abnormalities of tractography were classified into three types by shape; "Disrupted", "Narrowing", and "Tapering". More abnormalities of tractography were found in patients with lumbar spinal stenosis, and especially in patients with foraminal stenosis. The disrupted type was the most common. The mean FA of entrapped symptomatic nerves was less than seen on the intact side. This study demonstrates that tractography shows abnormal findings for nerve roots in lumbar spinal degeneration and that FA decreases in symptomatic roots. DTI may offer not only morphological evaluation, but also quantitative evaluation. We believe that DTI can be used as a tool for the diagnosis of lumbar spinal degenerative disease.

Effect of photodynamic therapy on local muscle treatment in a rat muscle injury model: a controlled trial

Background

Muscle injury is common and is thought to account for 10%–50% of all sports-related injuries. The use of rest, ice, compression, and elevation is common in clinical practice, but many treatments over a long period are required to produce a therapeutic effect. We evaluated the utility of photodynamic therapy as a new treatment option for the acute stage of muscle injury.

Methods

Twenty 8-week-old Sprague-Dawley male rats underwent experimental injury of the right gastrocnemius muscle with a drop-mass method. After muscle injury was induced, a liposomally formulated indocyanine green derivative (7 mg/kg) near-infrared laser irradiation was performed at 18 h after injury. Local time-dependent changes in the treatment (n = 14) and no treatment (n = 14) groups were evaluated with in vivo imaging, histologic examination, and enzyme-linked immunosorbent assay methods.

Results

In vivo imaging fluorescence values were significantly higher in the no treatment group, whereas interleukin-6 and tumor necrosis factor-α levels were significantly higher in the treatment group at 18 h after injury. Histologic examination results revealed that the treatment group had less bleeding and more degeneration repair processes than the no treatment group at 24 h and 1 week after muscle injury.

Conclusions

These findings suggest that photodynamic therapy promotes a tissue-repairing effect during the early stage of muscle injury.