Long-term functional and radiological outcomes of cervical disc arthroplasty at a tertiary level spine center in India: A retrospective cohort analysis with minimum 2 years of follow-up.

Context: Cervical disc arthroplasty (CDA) was developed for the treatment of cervical disc disease with the potential advantages of preservation of physiological motion at a discal level, thereby potentially reducing adjacent level stresses and degeneration, which were a known complication of anterior cervical arthrodesis. The objective of this study was the assessment of long-term functional and radiological outcomes overtime in all the patients who underwent CDA from 2011 to 2019 at our institute. Materials and Methods: Forty-eight patients who underwent CDA (2011-2019) with a minimum 2-year follow-up were retrospectively evaluated. The functional outcome included the Visual Analog Score (VAS) and Neck Disability Index (NDI). Radiographs were assessed for range of motion (ROM) at the index surgical level, presence of heterotopic ossification (HO), and adjacent segment degeneration. Results: The mean follow-up was 5.79 ± 2.96 (2.16-11.75) years. Significant improvement (P < 0.05) was observed in the VAS (8.91 ± 2.52 [preoperative] to 0.89 ± 1.27 [follow-up]) and NDI (65.5% ±23.06% [preoperative] to 4.79 ± 3.87 [follow-up]) score. Motion at index level increased significantly from 5.53° preoperatively to 7.47°, and 92% of the implanted segments were still mobile (referring to the threshold of ROM > 3°). HOs are responsible for the fusion of 4/50 (8%) levels at the last follow-up. Distal and proximal adjacent disc degeneration occurred in 36% and 28% of patients, respectively. No migration of the implant was observed on the radiograph. Conclusion: Our study showed favorable clinical outcome of CDA with preservation of ROM at the index surgical level. CDA can be a promising alternative to anterior cervical arthrodesis when properly indicated.

Comparative Study on Accuracy of Intra-Operative Computed Tomography-Navigation Based Pedicle Screw Placement With Skin vs Bone Fixed Dynamic Reference Frame in Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective comparative study. OBJECTIVE: To compare the accuracy of intra-operative navigation-assisted percutaneous pedicle screw insertion between bone fixed and skin fixed dynamic reference frame (DRF) in Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). METHODS: Between October 2018 and September 2022, patients who underwent MIS-TLIF were included in this study with DRF fixed either on bone (group B) or skin (group S). Pedicle screws were inserted under the guidance of intra-operative Cone bean Computed tomography (cbCT) based navigation. Accuracy of pedicle screw placement was immediately checked by a final intra-operative cbCT Spin. RESULTS: Among 170 patients, group B included 91 patients and group S included 79 patients. Out of total 680 screws, 364 screws (group B) and 316 screws (group S) were placed. Patient's demographic data and distribution of screws showed no statistically significant difference. The accuracy showed no significant difference between both the groups (94.5% in group B and 94.3% in group S). CONCLUSION: Skin fixed DRF can serve as an alternate way for placement and avoids extra incision with similar accuracy in pedicle screw insertions with bone fixed DRF using intra-operative CT guided navigation in MIS TLIF.

Nonlinear Finite Element Calculations of Layered SAW Resonators.

In this work the nonlinear behavior of layered SAW resonators is studied with the help of Finite Element (FE) computations. The full calculations depend strongly on the availability of accurate tensor data. While there are accurate material data for linear computations, the complete sets of higher-order material constants, needed for nonlinear simulations, are still not available for relevant materials. To overcome this problem, scaling factors were used for each available nonlinear tensor. The approach here considers piezoelectricity, dielectricity, eletrostriction and elasticity constants up to fourth order. These factors act as a phenomenological estimate for incomplete tensor data. Since no set of fourth order material constants for LiTaO3 is available, an isotropic approximation for the fourth order elastic constants was applied. As a result, it was found that the fourth order elastic tensor is dominated by one fourth order Lamé constant. With the help of the FE model, derived in two different, but equivalent ways, we investigate the nonlinear behavior of a SAW resonator with a layered material stack. The focus was set to third order nonlinearity. Accordingly, the modeling approach is validated using measurements of third order effects in test resonators. In addition, the acoustic field distribution is analyzed.

Prevalence and Risk Factors of Hypertension among Police Personnel of District Gwalior- A Cross Sectional Study.

Context: Hypertension is an emerging public health problem due to its high prevalence and association with cardiovascular and overall morbidity and mortality. Police personnel constitute a special occupational group with exposure to violence and stress at work, which affects their health directly and indirectly. Methodology: A cross-sectional study was conducted to find out the prevalence of hypertension and its relation with respect to police duty profile along with other risk factors among the police personnel of the Gwalior district stationed at various police stations. Results: In total, 402 police personnel were included in the study. Forty (14.7%) participants reported that they had h/o hypertension, while 26 (9.5%) reported that they were diagnosed as hypertensive in recent 1-2 months. As per the findings of our study, 273 (67.91%) participants come out to be hypertensive; among them, 207 (75.8%) were diagnosed in the current study. With increase in hierarchy, more police personnel suffered with hypertension. Conclusions: Long duty hours, higher rank, prolonged service duration, and inappropriate eating habits are the significant factors for the high prevalence of hypertension in police personnel.

Dural Venous Sinus Thrombosis after Vestibular Schwannoma Surgery: The Anticoagulation Dilemma.

Introduction Dural venous sinus thrombosis (DVST) is a relatively understudied complication of vestibular schwannoma (VS) surgery. Several studies have examined this topic; however, there is limited data on the incidence, clinical progression, and proper management of this patient population. Methods A retrospective review was performed for patients undergoing surgery for VS at a single institution. All postoperative imaging was reviewed for incidence of DVST. Demographic data were collected including tumor and surgical characteristics along with postoperative course. Results A total of 63 patients underwent resection of their VS. The incidence of DVST was 34.9%. The operative time was greater in the dural venous sinus thrombosis (DSVT) group, at an average of 6.69 hours versus 4.87 in the no DSVT cohort ( p = 0.04). Tumor size was correlationally significant ( p = 0.051) at 2.75 versus 2.12 cm greatest diameter. The translabyrinthine approach was most prevalent (68.2%). The side of the thrombosis was ipsilateral to the tumor and surgery in all patients. The sigmoid sinus was most commonly involved (95.5%). Of them, 85% patients had a codominant or thrombus contralateral to the dominant sinus. All patients were asymptomatic. No patients were treated with anticoagulation. Resolution of thrombus was seen in five (22.7%) of the patients on last follow-up imaging. There were no hemorrhagic complications. Conclusion The overall incidence of DVST was (34.9%) of 63 patients who underwent VS surgery. All patients were asymptomatic and none were treated with anticoagulation. In our study, continuing to observe asymptomatic patients did not lead to any adverse events.

Investigation on Third-Order Intermodulation Distortions Due to Material Nonlinearities in TC-SAW Devices.

Nonlinearity can give rise to intermodulation distortions in surface acoustic wave (SAW) devices operating at high input power levels. To understand such undesired effects, a finite element method (FEM) simulation model in combination with a perturbation theory is applied to find out the role of different materials and higher order nonlinear tensor data for the nonlinearities in such acoustic devices. At high power, the SAW devices containing metal, piezoelectric substrate, and temperature compensating (TC) layers are subject to complicated geometrical, material, and other nonlinearities. In this paper, third-order nonlinearities in TC-SAW devices are investigated. The materials used are LiNbO3-rot128YX as the substrate and copper electrodes covered with a SiO2 film as the TC layer. An effective nonlinearity constant for a given system is determined by comparison of nonlinear P-matrix simulations to third-order intermodulation measurements of test filters in a first step. By employing these constants from different systems, i.e., different metallization ratios, in nonlinear periodic P-matrix simulations, a direct comparison to nonlinear periodic FEM-simulations yields scaling factors for the materials used. Thus, the contribution of the different materials to the nonlinear behavior of TC-SAW devices is obtained and the role of metal electrodes, substrate, and TC film are discussed in detail.

A Method for Accurate Modeling of BAW Filters at High Power Levels.

A novel approach for multiphysics modeling of bulk acoustic wave (BAW) filters is presented allowing accurate and at the same time efficient modeling of BAW filters at high power levels. The approach takes the different types of losses and their spatial distribution into account in order to provide the required input for thermal simulation. The temperature distribution determined by thermal simulation is used to modify the geometry and the layer stack of each single resonator of the filter. In this way, the required input for modeling of electromagnetic (EM) and acoustic behavior at high power level is generated. The high accuracy of the modeling approach is verified by the measurements of the S-parameters and the temperature distribution by infrared thermography during high-power loads. Moreover, the influence of the nonlinear behavior on the frequency shift of the resonance frequency is investigated. For this purpose, a parameterized nonlinear Mason model has been combined with a 3-D EM finite-element method and the required nonlinear material parameters were determined by fitting simulation results to the measured polyharmonic distortion model (X-parameters) of a BAW resonator.

Simple dispersion law for arbitrary sequences of dispersive optics.

We give a simple general formula for the total angular dispersion due to multiple arbitrary dispersive elements in a series. It is simply the sum of the individual elements' angular dispersions but with each divided by the total spatial magnification afterward (or, equivalently, multiplied by the total angular magnification afterward).

Measuring extremely complex pulses with time-bandwidth products exceeding 65,000 using multiple-delay crossed-beam spectral interferometry.

We measure the complete electric field of extremely complex ultrafast waveforms using the simple linear-optical, interferometric pulse-measurement technique, MUD TADPOLE. The waveforms were measured with ~40 fs temporal resolution over a temporal range of ~3.5 ns and had time-bandwidth products exceeding 65,000. The approach is general and could allow the measurement of arbitrary optical waveforms.

Highly simplified device for measuring the intensity and phase of picosecond pulses.

We demonstrate an extremely simple frequency-resolved-optical-gating (GRENOUILLE) device for measuring the intensity and phase of relatively long--ps--pulses. In order to achieve the required high spectral resolution and large temporal range, it uses a few-cm-thick second-harmonic-generation crystal in the shape of a pentagon. This has the additional advantage of reducing the device's total number of components to as few as three simple easily aligned optics, making it the simplest device ever developed for complete pulse measurement. We report complete intensity-and-phase measurements of pulses up to 15ps long with a time-bandwidth product of 21.

Measuring temporally complex ultrashort pulses using multiple-delay crossed-beam spectral interferometry.

We introduce a spectral-interferometry (SI) technique for measuring the complete intensity and phase of relatively long and very complex ultrashort pulses. Ordinarily, such a method would require a high-resolution spectrometer, but our method overcomes this need. It involves making multiple measurements using SI (in its SEA TADPOLE variation) at numerous delays, measuring many temporal pulselets within the pulse, and concatenating the resulting pulselets. Its spectral resolution is the inverse delay range--many times higher than that of the spectrometer used. Our simple proof-of-principle implementation of it provided 71 fs temporal resolution and a temporal range of 100 ps using a few-cm low-resolution spectrometer.

Propagation dependence of chirp in Gaussian pulses and beams due to angular dispersion.

The chirp acquired by a Gaussian ultrashort pulse due to angular dispersion, unlike that of plane waves, increases nonlinearly with propagation distance and eventually asymptotes to a constant. However, this interesting result has never been directly measured. In this Letter, we use two-dimensional spectral interferometry to measure the propagation dependence of the chirp for Gaussian ultrashort pulses and beams with angular dispersion. The measured chirp as a function of propagation distance agreed well with theory. This work verifies both an equation and a measurement technique that will be useful for predicting or determining the pulse's chirp in ultrafast optics experiments that contain angular dispersion.

Role of bile bacteria in gallbladder carcinoma.

BACKGROUND/AIMS: Long standing calculus disease has been observed to be a risk factor for gallbladder carcinoma. However it is possible that calculi may be incriminated by some means other than just chronic irritation. Calculi may induce an element of stasis, promoting chronic infection leading to increased turnover of primary bile acids to secondary bile acids, which are known tumor promoters and initiators. This study aimed to find the prevalence of biliary microflora in gallbladder carcinoma and association of gallbladder carcinoma with chronic bacterial infection and bile acid profile. METHODOLOGY: Bile culture was done in 390 patients divided into 3 groups--gallbladder carcinoma 65 (17%), cholelithiasis 125 (32%) and control group 200 (51%). Serum samples were analyzed for presence of Vi antibody for chronic typhoid carrier state and bile acid analysis was done in 10 patients in each group. RESULTS: 116 (30%) patients had culture positive bile. Significantly higher number of patients with gallbladder carcinoma 40 (65%) had culture positive bile as compared to cholelithiasis 52 (42%) and control 24 (12%). Vi Antibodies suggestive of chronic typhoid carrier state were found to be significantly higher in the gallbladder carcinoma group 20 (31%) as compared to controls 22 (11%) (OR 3.596, p < 0.05) however, the difference was statistically insignificant in the cholelithiasis group 12 (11%) (OR 0.859, p > 0.05). There was a 6.84 times higher risk of developing gallbladder carcinoma in culture positive cholelithiasis patients and 5.14 times if both Vi antibody and cultures were positive. Bile analysis showed primary bile acids cholic acid and chenodeoxycholic acid to be lower while secondary bile acids deoxycholic acid and lithocholic acid to be more in the gallbladder carcinoma group (7.268 mg/mL, 9.183 mg/ mL, 14.468 mg/mL, 3.312 mg/mL respectively) than cholelithiasis (17.50 mg/mL, 13.80 mg/mL, 6.07 mg/ mL, 2.05 mg/mL) and control group (19.85 mg/mL, 16.53 mg/mL, 2.71 mg/mL, 1.128 mg/mL respectively). The difference was statistically significant. CONCLUSIONS: Chronic bacterial infection of bile leading to production of carcinogenic precursors might be one of the etiological factors in the pathogenesis of gallbladder carcinoma and hence a target for its prevention.

Telomerase activation--one step on the road to carcinoma of the gall bladder.

BACKGROUND: As information on telomeres and telomerase dynamics in the regulation of cell cycle events accumulates, new opportunities for application to gerontology and cancer therapy are emerging. The aim of this study was to detect the telomerase activity (hTERT protein) in the biopsy specimens of human carcinoma of the gall bladder. PATIENTS AND METHODS: Thirty cases each of carcinoma of the gall bladder and cholelithiasis (controls) were analysed. Immunohistochemistry was employed using mouse monoclonal antibody against hTERT protein and by taking human tonsil and testicular tissue as positive controls. RESULTS: Seventeen cases (56.66%) of carcinoma of the gall bladder and 2 cases (6.66%) of cholelithiasis were strongly positive for telomerase. The difference was statistically significant (p<0.001). Six cases (20%) of gall bladder carcinoma and one case (3.33%) of cholelithiasis were weakly positive. The difference was highly statistically significant (p<0.001). Telomerase activity was mainly concentrated in poorly-differentiated adenocarcinomas (83.33%) and increased expression was noted in advanced stages. CONCLUSION: The presence of telomerase may serve as a molecular marker for the diagnosis of gall bladder carcinoma and may have prognostic and therapeutic implications in the treatment of patients in the future.