Painful knee arthroplasty

A triple-tracer nuclear medicine study that incorporates (99m)Tc-sulfur colloid, (111)In-labeled leukocytes, and (99m)Tc-methylene diphosphonate can be useful for the diagnosis of aseptic loosening in a patient after total-knee arthroplasty, as demonstrated in this case study. The triple-tracer technique takes less time and is more accurate than a bone scan alone.

Determination of accuracy and precision of lesion uptake measurements in human subjects with time-of-flight PET

Inclusion of time-of-flight (TOF) information in PET reconstructions has been demonstrated to improve image quality through better signal-to-noise ratios, faster convergence, better lesion detectability, and better image uniformity. The goal of this work was to assess the impact of TOF information on the accuracy and precision of quantitative measurements of activity uptake in small lesions in clinical studies.

METHODS

Data from small (10-mm diameter) spheres were merged with list-mode data from 6 healthy volunteers after injection of (18)F-FDG. Six spheres having known activity uptake with respect to the average whole-body uptake were embedded in both the liver and the lung of the subject's data. Images were reconstructed with TOF information and without TOF information (non-TOF reconstruction). The measured uptake was compared with the known activity; variability was measured across 60 bootstrapped replicates of the merged data, across the 6 spheres within a given organ, and across all spheres in all subjects.

RESULTS

The average uptake across all spheres and subjects was approximately 50% higher in the lung and 20% higher in the liver with TOF reconstruction than with non-TOF reconstruction at comparable noise levels. The variabilities across replicates, across spheres within an organ, and across all spheres and subjects were 20%-30% lower with TOF reconstruction than with non-TOF reconstruction in the lung; in the liver, the variabilities were 10%-20% lower with TOF reconstruction than with non-TOF reconstruction.

CONCLUSION

TOF reconstruction leads to more accurate and precise measurements, both within a subject and across subjects, of the activity in small lesions under clinical conditions.

In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty

Patient specific instrumentation (PSI) was developed to increase total knee arthroplasty (TKA) accuracy and efficiency. The study purpose was to compare immediate post-operative mechanical alignment, achieved using PSI, with conventional and computer assisted surgery (CAS) instruments in high volume TKA practices. This prospective, multicenter, non-randomized study accrued 66 TKA patients using PSI. A computed tomography (CT) based algorithm was used to develop the surgical plan. Sixty-two percent were females, 99% were diagnosed with osteoarthritis, average age at surgery was 66 years, and 33 was the average body mass index. A historical control group was utilized that underwent TKA using conventional instruments (n=86) or CAS (n=81), by the same set of surgeons. Postoperative mechanical alignment was comparable across the groups. Operative time mean and variance were significant.

Transoral sonographic diagnosis of submandibular duct calculi

We present a case of submandibular duct calculi diagnosed using transoral sonography. Sonography is the first-line imaging modality of salivary gland calculi. However, it is performed via a transcutaneous approach, which is limited in identifying small salivary duct calculi. Using an intraoral transducer, transoral sonography can visualize the submandibular duct and detect the presence of small calculi, thus overcoming the limitations of transcutaneous sonography.

Telesonography: virtual 3D image processing of remotely acquired abdominal, vascular, and fetal sonograms

PURPOSE

To design and test a new telesonography technique using remote volume acquisition by untrained operators in locations without access to trained sonographers, postprocessing, and interpretation done at expert centers.

MATERIALS AND METHODS

The technique was tested with 84 sonograms of organs acquired in pregnant women (n = 8) and patients with various abdominal pathologic conditions (n = 11) located in French Guyana (France), Ceuta (Spain), and Murighiol (Romania). An operator inexperienced in sonography (US) placed the transducer over the predetermined acoustic window for each organ, then swept it from a -45° to a +45° position to scan the targeted organ. The acquired volume dataset was sent to an expert center via the Internet and reconstructed using a proprietary software, which allowed a trained sonographer to navigate through the appropriately reconstructed sonograms.

RESULTS

After three-dimensional processing at the expert center, the organs scanned in the obstetrical cases were adequately visualized by the expert in seven of eight (88%) examinations of the fetal head, femur, and umbilical cord and eight of eight (100%) examinations of the fetal abdomen and placenta, whereas in the general abdominal cases, the liver, gallbladder, portal vein, and right kidney were correctly visualized in 10 of 11 (91%) examinations.

CONCLUSIONS

Telesonography allowed untrained operators to scan and transfer the US volume datasets over the Internet to an expert center where an expert sonographer could navigate through the reconstructed US volume and visualize sonograms of diagnostic quality.

The effects of lumbar facet dowels on joint stiffness: a biomechanical study

BACKGROUND

Facet joint arthrosis may play a significant role in low back pain generation. The placement of facet dowels is a percutaneous treatment that aims to fuse the facets and increase joint stiffness. In this cadaveric study, we evaluated spine stiffness after facet dowel insertion in combination with several surgical procedures and determined which motions promote dowel migration.

METHODS

Six fresh frozen lumbar spines were tested in flexion-extension, lateral bending, and axial rotation. Spine stiffness was determined for the intact specimens, after L4 laminectomy, and after bilateral L4-L5 facet dowel placement, respectively. One specimen underwent a unilateral transforaminal lumbar interbody fusion (TLIF) construct and another underwent extreme lateral interbody fusion (XLIF) graft (22 mm) placement, followed by placement of facet dowels. Afterwards, the specimens were subjected to 10,000 cycles of fatigue testing in flexion-extension or axial rotation.

RESULTS

The overall decrease in stiffness after laminectomy was 4.6%. Facet dowel placement increased overall stiffness by 7.2%. The greatest increase was seen with axial rotation (13%), compared to flexion, extension, and lateral bending (9.5%, 2.3%, and 5.6%, respectively). The TLIF and XLIF plus dowel construct increased specimen stiffness to 266% and 163% of baseline, respectively. After fatigue testing, dowel migration was detected by computed tomography in the 2 uninstrumented specimens undergoing axial rotation cycling.

CONCLUSION

Facet dowels increase the stiffness of the motion segment to which they are applied and can be used in conjunction with laminectomy procedures to increase the stiffness of the joint. However, dowel migration can occur after axial rotation movements. Hybrid TLIF or XLIF plus facet dowel constructs have significantly higher stiffness than noninstrumented ones and may prevent dowel migration.

Thoracolumbar fracture dislocations treated by posterior reduction, interbody fusion and segmental instrumentation

BACKGROUND

Literature describing the application of modern segmental instrumentation to thoracic and lumbar fracture dislocation injuries is limited and the ideal surgical strategy for this severe trauma remains controversial. The purpose of this article was to investigate the feasibility and efficacy of single-stage posterior reduction with segmental instrumentation and interbody fusion to treat this type of injury.

MATERIALS AND METHODS

A retrospective review of 30 patients who had sustained fracture dislocation of the spine and underwent single stage posterior surgery between January 2007 and December 2011 was performed. All the patients underwent single stage posterior pedicle screw fixation, decompression and interbody fusion. Demographic data, medical records and radiographic images were reviewed thoroughly.

RESULTS

Ten females and 20 males with a mean age of 39.5 years were included in this study. Based on the AO classification, 13 cases were Type B1, 4 cases were B2, 4 were C1, 6 were C2 and 3 cases were C3. The average time of the surgical procedure was 220 min and the average blood loss was 550 mL. All of the patients were followed up for at least 2 years, with an average of 38 months. The mean preoperative kyphosis was 14.4° and reduced to -1.1° postoperatively. At the final followup, the mean kyphosis was 0.2°. The loss of correction was small (1.3°) with no significant difference compared to postoperative kyphotic angle (P = 0.069). Twenty seven patients (90%) achieved definitive bone fusion on X-ray or computed tomography imaging within 1 year followup. The other three patients were suspected possible pseudarthrosis. They remained asymptomatic without hardware failure or local pain at the last followup.

CONCLUSION

Single stage posterior reduction using segmental pedicle screw instrumentation, combined with decompression and interbody fusion for the treatment of thoracic or lumbar fracture-dislocations is a safe, less traumatic and reliable technique. This procedure can achieve effective reduction, sagittal angle correction and solid fusion.

Calibration of quartz tuning fork spring constants for non-contact atomic force microscopy: direct mechanical measurements and simulations

Quartz tuning forks are being increasingly employed as sensors in non-contact atomic force microscopy especially in the "qPlus" design. In this study a new and easily applicable setup has been used to determine the static spring constant at several positions along the prong of the tuning fork. The results show a significant deviation from values calculated with the beam formula. In order to understand this discrepancy the complete sensor set-up has been digitally rebuilt and analyzed by using finite element method simulations. These simulations provide a detailed view of the strain/stress distribution inside the tuning fork. The simulations show quantitative agreement with the beam formula if the beam origin is shifted to the position of zero stress onset inside the tuning fork base and torsional effects are also included. We further found significant discrepancies between experimental calibration values and predictions from the shifted beam formula, which are related to a large variance in tip misalignment during the tuning fork assembling process.

Evaluation of Erytra® fully automated analyser for Routine Use in Transfusion Laboratory

OBJECTIVE

To evaluate efficiency and performance of Erytra® analyser in comparison to the reference platform of the NBT immunohaematology laboratory (Bio-Rad ID-System).

BACKGROUND

Moving to automation or semi-automation is a major focus of transfusion centres. The Erytra® (Grifols) is a new fully automated walk-away analyser with high volume processing capacity for pre-transfusion testing, designed to be used with the unique 8-column DG Gel® cards.

STUDY DESIGN AND METHODS

A total of 2201 immunohaematological tests (1041 ABO/D grouping, 1041 antibody screening, 51 antibody identification, 45 newborns (ABO/D and DAT) and 23 crossmatches were performed on 1160 donor/patient whole blood samples. Erytra®'s performance was assessed by means of a stress test replicating the routine work of a hospital laboratory.

RESULTS

Concordant results between the Erytra® and the reference method were obtained in 2195 (99·73 %) of the tests. There were only three discrepancies out of 6246 reactions (0·05%) in ABO/D grouping, all in the reverse group which did not mislead to group identification. Of the 1041 samples screened for antibody presence, Erytra® detected all the relevant antibodies [9 not detected weak prophylactic anti-D were determined to be clinically nonsignificant (<0·1 IU mL(-1) )] while Bio-Rad ID-System missed one anti-e and one anti-Jk(a) . Concordance for D grouping, crossmatching and newborns was 100%. Results of the simulated stress test exercise highlighted the capacity of Erytra® for absorbing into 4 h workloads equivalent to 24 h of routine.

CONCLUSIONS

Grifols' Erytra® analyser showed reliable high sensitivity, velocity and capacity to cope with high workload in the immunohaematology laboratory routine.

Infection with spinal instrumentation: Review of pathogenesis, diagnosis, prevention, and management

Background:

Instrumentation has become an integral component in the management of various spinal pathologies. The rate of infection varies from 2% to 20% of all instrumented spinal procedures. Every occurrence produces patient morbidity, which may adversely affect long-term outcome and increases health care costs.

Methods:

A comprehensive review of the literature from 1990 to 2012 was performed utilizing PubMed and several key words: Infection, spine, instrumentation, implant, management, and biofilms. Articles that provided a current review of the pathogenesis, diagnosis, prevention, and management of instrumented spinal infections over the years were reviewed.

Results:

There are multiple risk factors for postoperative spinal infections. Infections in the setting of instrumentation are more difficult to diagnose and treat due to biofilm. Infections may be early or delayed. C Reactive Protein (CRP) and Magnetic Resonance Imaging (MRI) are important diagnostic tools. Optimal results are obtained with surgical debridement followed by parenteral antibiotics. Removal or replacement of hardware should be considered in delayed infections.

Conclusions:

An improved understanding of the role of biofilm and the development of newer spinal implants has provided insight in the pathogenesis and management of infected spinal implants. This literature review highlights the mechanism, pathogenesis, prevention, and management of infection after spinal instrumentation. It is important to accurately identify and treat postoperative spinal infections. The treatment is often multimodal and prolonged.

Apical root canal transportation and remaining dentin thickness associated with ProTaper Universal with and without PathFile

INTRODUCTION

This study aimed to compare, using digital subtraction radiography, apical transportation in mesiobuccal root canals of extracted human maxillary molars instrumented with ProTaper Universal F3 and F4 files (Dentsply Maillefer, Ballaigues, Switzerland) with and without the prior creation of glide paths using the PathFile system and to compare, using cone-beam computed tomographic imaging, remaining dentin thickness (RDT) after complete preparation.

METHODS

Forty mesiobuccal roots with curvatures of 20°-35° were used. In group A, glide paths were created with PathFile #1, #2, and #3 to the working length; in group B, no glide paths were used. All canals were instrumented up to F4 to the working length. Digital subtraction radiographic images were obtained in buccolingual and mesiodistal directions. Apical transportation associated with F3 or F4 was calculated based on the difference between the tip of the first and the last instrument analyzed in each group. RDT was calculated based on cone-beam computed tomographic images.

RESULTS

Apical transportation was higher after F4 regardless of the use of the PathFile system. No statistically significant differences between groups A and B were observed in apical transportation after instrumentation with F3 or F4 (P > .05). Group A showed greater RDT values at 2 (buccal and mesial walls, P < .05) and 3 mm (buccal and distal walls, P < .05) from the apex but not at 1 mm.

CONCLUSIONS

The use of the PathFile system before root canal preparation with ProTaper Universal F3 and F4 did not influence apical transportation but was associated with greater RDTs at 2 and 3 mm from the apex.

Measurement of plasma viscosity by free oscillation rheometry: imprecision, sample stability and establishment of a new reference range

BACKGROUND

Plasma viscosity (PV) is used in the investigation of hyperviscosity syndrome. We have evaluated the performance of a new bench-top free oscillation rheometer, ReoRox from Medirox, and established a new reference range.

METHODS

Performance of the free oscillation rheometry (FOR) method was evaluated examining within-run and between-run imprecision, duration of measurement and operator simplicity. Furthermore, influence of storage on the PV measurements was assessed and a reference range based on plasma from 585 healthy men and women was established.

RESULTS

Imprecision of the free oscillation rheometer was comparable to other viscometers and performance of the instrument was satisfying. The non-parametrical reference range established was 1.22-1.44 mPa s at 37℃ (2.5th and 97.5th percentiles).

CONCLUSIONS

We have established a FOR PV reference range to support clinical decision-making. Furthermore, we found high pre-analytical stability of the samples and an analytical imprecision comparable to other PV methods.

Removal of the gadolinium interference from the measurement of selenium in human serum by use of collision cell quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS)

BACKGROUND

Measurement of selenium in serum is an important clinical biomarker of nutritional status. The presence of gadolinium (Gd) in samples following administration of the contrast agents used for magnetic resonance imaging (MRI) results in a significant positive bias when using quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS).

METHODS

Three instrumental set-ups were assessed: standard mode with no collision gas and collision cell mode with either a hydrogen:helium mixture or hydrogen. The effect of Gd on the selenium (Se) signal was assessed using external quality assurance (EQA) specimens and internal quality control (IQC) materials, both unspiked and spiked with Gd. Serum previously shown to contain high concentrations of Gd-containing contrast agents were also analysed.

RESULTS

Recoveries of Se in the spiked compared to the unspiked samples were: between 500% and 1300% using standard mode; 100% and 29,000% using collision cell mode with hydrogen:helium mixture; and between 99% and 103% using hydrogen. The use of H2 in the collision cell provided accurate results, indicating that the charge exchange reaction (CER) of Gd(2+) with H2 removes this interference. Analysis of patient serum known to contain the Gd contrast agent using the method gave results within the selenium reference range (adults 0.89-1.65 µmol/L). The presence of Gd, as low as 0.2 mg/L, in serum samples causes a positive interference on the measurement of Se by ICP-MS.

CONCLUSIONS

Using a CER mode with pure H2 in the collision cell it was possible to fully remove the interference due to Gd(2+) from the signal for Se.

A review of methods for sensing the nitrogen status in plants: advantages, disadvantages and recent advances

Nitrogen (N) plays a key role in the plant life cycle. It is the main plant mineral nutrient needed for chlorophyll production and other plant cell components (proteins, nucleic acids, amino acids). Crop yield is affected by plant N status. Thus, the optimization of nitrogen fertilization has become the object of intense research due to its environmental and economic impact. This article focuses on reviewing current methods and techniques used to determine plant N status. Kjeldahl digestion and Dumas combustion have been used as reference methods for N determination in plants, but they are destructive and time consuming. By using spectroradiometers, reflectometers, imagery from satellite sensors and digital cameras, optical properties have been measured to estimate N in plants, such as crop canopy reflectance, leaf transmittance, chlorophyll and polyphenol fluorescence. High correlation has been found between optical parameters and plant N status, and those techniques are not destructive. However, some drawbacks include chlorophyll saturation, atmospheric and soil interference, and the high cost of instruments. Electrical properties of plant tissue have been used to estimate quality in fruits, and water content in plants, as well as nutrient deficiency, which suggests that they have potential for use in plant N determination.

A prototype direct-detection CCD for protein crystallography

The fabrication and testing of a prototype deep-depletion direct-conversion X-ray CCD detector are described. The device is fabricated on 600 µm-thick high-resistivity silicon, with 24 × 24 µm pixels in a 4k × 4k pixel format. Calibration measurements and the results of initial protein crystallography experiments at the Cornell High Energy Synchrotron Source (CHESS) F1 beamline are described, as well as suggested improvements for future versions of the detector.

Fast measurement of sarcomere length and cell orientation in Langendorff-perfused hearts using remote focusing microscopy

RATIONALE

Sarcomere length (SL) is a key indicator of cardiac mechanical function, but current imaging technologies are limited in their ability to unambiguously measure and characterize SL at the cell level in intact, living tissue.

OBJECTIVE

We developed a method for measuring SL and regional cell orientation using remote focusing microscopy, an emerging imaging modality that can capture light from arbitrary oblique planes within a sample.

METHODS AND RESULTS

We present a protocol that unambiguously and quickly determines cell orientation from user-selected areas in a field of view by imaging 2 oblique planes that share a common major axis with the cell. We demonstrate the effectiveness of the technique in establishing single-cell SL in Langendorff-perfused hearts loaded with the membrane dye di-4-ANEPPS.

CONCLUSIONS

Remote focusing microscopy can measure cell orientation in complex 2-photon data sets without capturing full z stacks. The technique allows rapid assessment of SL in healthy and diseased heart experimental preparations.

A comparison of dentin cutting efficiency of 4 round-tipped ultrasonic instruments

INTRODUCTION

Ultrasonic instruments are available for a variety of endodontic uses. Few published evaluations exist that compare the dentin cutting efficiency of endodontic ultrasonic tips. Furthermore, previous comparison studies often did not take into account 2 critical factors: clinically relevant downward forces and linear movement during use.

METHODS

Four different round-tipped ultrasonic tips were compared (n = 5 per tip group): BUC-1 (Obtura Spartan, Fenton, MO), BL-2 (B&L Biotech, Bala Cynwyd, PA), BL-3 (B&L Biotech), and START-X #2 (Dentsply Maillefer, Ballaigues, Switzerland). The tips were attached to a testing apparatus that applied a 15-g axial force and a linear movement during instrumentation of a human dentin specimen. Instrumentation was completed at the manufacturers' recommended power settings, and 3 of the tips were also compared at an equal power setting. Instrumentation consisted of 20-second cycles for a total of 6 minutes. Dentin specimens were weighed at baseline and after 2, 4, and 6 minutes of instrumentation. The dentin cutting efficiency was measured by the change in weight of dentin specimens to the nearest 0.1 mg.

RESULTS

A 1-factor analysis of variance and Tukey post hoc analysis of cumulative dentin removal (after 6 minutes of instrumentation) revealed a statistically significant difference among the 4 ultrasonic tips (P ≤ .0001) at the recommended PS, with the BUC-1 tip removing significantly more dentin across time. At an equal power setting, the BUC-1 was significantly more efficient than the BL-3; no difference was found between the BUC-1 and the BL-2.

CONCLUSIONS

Within the limits of this study, the BUC-1 showed the greatest dentin removal. Adding a linear movement and a clinically relevant axial force allows better generalization to clinical applications.

Effects of a new pocket device for negative pressure wound therapy on surgical wounds of patients affected with Crohn's disease: a pilot trial

INTRODUCTION

Surgical site infections (SSIs) affect costs of care and prolong length of stay. Crohn's disease (CD) represents an independent risk factor for SSI. The risk can be further increased by concomitant administration of immunosuppressive drugs and poor performance status at the time of surgery. Patients suffering from CD often need more than one surgical intervention during life, sometimes requiring fashioning of a stoma. The aim of this pilot study was to compare a portable device for negative pressure wound therapy (PICO, Smith & Nephew, London, UK) to conventional gauze dressings in patients undergoing surgery for stricturing CD.

METHODS

Between January 2010 and November 2011, this controlled trial enrolled 30 patients, who were assigned to treatment with either PICO (n = 13) or conventional dressings (n = 17). Each patient completed a 3-month follow-up.

RESULTS

Patients receiving PICO experienced significantly less postoperative wound complications (P = .001) and SSI (P = .017) compared with those who received conventional dressings. This resulted in shorter hospital stay (P = .0007). No significant differences in cosmetic results were found.

CONCLUSION

These data suggest that PICO allows faster and safe discharge by reducing the incidence of SSI and wound-related complications in selected patients undergoing surgical intervention for stricturing CD. This could be particularly useful in patients receiving steroids.

Accuracy of intraoperative computed tomography-based navigation for placement of percutaneous pedicle screws

MISS techniques have gained recent popularity. The proposed benefits of these techniques include reduced tissue trauma, reduced blood loss, less perioperative pain, and a quicker recovery and return to normal activities. The purpose of this study was to evaluate the accuracy of intraoperative computed tomography (CT)-based navigation for placement of percutaneous pedicle screws in a cadaveric model. Outcome measures included accuracy of screw placement. Two cadaveric specimens were utilized. CT images were obtained using an O-Arm (Medtronic, Memphis, Tennessee, United States) and were coupled to the Stealth navigation system (Medtronic). Computer navigation was used for placement of percutaneous pedicle screws. Screws were placed bilaterally from T5 to S1. Postinsertion CT scans were obtained. Pedicle breach was assessed and classified (I: none, II: < 2 mm, III: 2 to 4 mm, or IV: > 4 mm) with direction of breach. Thirty thoracic screws were placed with 3 (10%) medial breaches and 17 (56.7%) lateral breaches (grade III). Of 20 lumbar screws there were 0 medial breaches and 2 (10%) lateral breaches (1 grade III, 1 grade IV). Four sacral screws were placed without breaches. The real-time computer-aided navigation tool ("simulated screw") was limited in identifying a breach. Manipulation of the surgeon's hand or driver could change the orientation of the navigation tool without changing the screw trajectory. CT-based navigation for percutaneous pedicle screw placement appears safe for the lumbar spine. Lateral thoracic breaches appeared commonly but were not felt to be clinically significant. The 10% rate of medial thoracic breach was concerning, but definitive conclusions could not be made due to the small sample size.

Collecting system percutaneous access using real-time tracking sensors: first pig model in vivo experience

PURPOSE

Precise needle puncture of the renal collecting system is an essential but challenging step for successful percutaneous nephrolithotomy. We evaluated the efficiency of a new real-time electromagnetic tracking system for in vivo kidney puncture.

MATERIALS AND METHODS

Six anesthetized female pigs underwent ureterorenoscopy to place a catheter with an electromagnetic tracking sensor into the desired puncture site and ascertain puncture success. A tracked needle with a similar electromagnetic tracking sensor was subsequently navigated into the sensor in the catheter. Four punctures were performed by each of 2 surgeons in each pig, including 1 each in the kidney, middle ureter, and right and left sides. Outcome measurements were the number of attempts and the time needed to evaluate the virtual trajectory and perform percutaneous puncture.

RESULTS

A total of 24 punctures were easily performed without complication. Surgeons required more time to evaluate the trajectory during ureteral than kidney puncture (median 15 seconds, range 14 to 18 vs 13, range 11 to 16, p=0.1). Median renal and ureteral puncture time was 19 (range 14 to 45) and 51 seconds (range 45 to 67), respectively (p=0.003). Two attempts were needed to achieve a successful ureteral puncture. The technique requires the presence of a renal stone for testing.

CONCLUSIONS

The proposed electromagnetic tracking solution for renal collecting system puncture proved to be highly accurate, simple and quick. This method might represent a paradigm shift in percutaneous kidney access techniques.

Through a glass darkly: glimpses into the future of mass spectrometry

The paper has three parts, (i) a brief overview of the main achievements made using mass spectrometry across all the fields of science, (ii) a survey of some of the topics currently being pursued most activity, including both applications and fundamental studies, and (iii) some hints as to what the future of mass spectrometry might hold with particular emphasis on revolutionary changes in the subject. Emphasis is given to ambient methods of ionization and their use in disease diagnosis and to their use in combination with miniature mass spectrometers for in-situ measurements. Special attention goes to the chemical aspects of mass spectrometry, including its emerging role as a preparative method based on accelerated bimolecular reaction rates in solution and on ion soft landing as a means of surface tailoring. In summary, the paper covers the proud history, vibrant present and expansive future of mass spectrometry.

Single screw-rod anterior instrumentation for thoracolumbar burst fractures with incomplete neurological deficit

PURPOSE

To evaluate the outcome of single screwrod anterior instrumentation for thoracolumbar burst fractures with incomplete neurological deficit.

METHODS

16 men and 5 women aged 22 to 55 (mean, 34) years underwent single screw-rod anterior instrumentation for thoracolumbar burst fractures with incomplete neurological deficit. The vertebrae involved were T10 (n=2), T11 (n=2), T12 (n=7), L1 (n=8), and L2 (n=2). No patient had disruption of the posterior ligament complex. Postoperatively, a thoracolumbar sacral orthosis was used until solid fusion. Outcome measures included neurological recovery, degree of kyphosis, complications, and pain and functional status of the patients.

RESULTS

The mean follow-up duration was 36 (range, 13-50) months. All patients recovered neurologically by at least one grade. Of the 21 patients, 6 improved from grade B to grade C (n=4) or grade D (n=2), 13 from grade C to grade D, and 2 from grade D to grade E. The mean degree of kyphosis improved from 23º ± 5º to 7º ± 3º. Seven patients had complications including ipsilateral basal atelectasis (n=3), urinary tract infection (n=1), haematuria (n=1), postoperative ileus (n=1), and superficial wound infection (n=1). None had iatrogenic visceral or vascular injury, pseudoarthrosis or hardware-related complications. Only one patient had severe back pain persistently.

CONCLUSION

Single screw-rod anterior instrumentation supplemented with an orthosis can be an alternative for double screw-rod anterior instrumentation for thoracolumbar burst fractures in patients with smaller vertebral bodies.

Side-cutting aspiration device for endoscopic and microscopic tumor removal

The authors present a unique side-cutting instrument (NICO Myriad, Indianapolis, IN) with variable aspiration designed specifically for tumor resection. The study included retrospective review of data collected from 10/2009 to 01/2011. We detail the use of the Myriad in 31 patients with the following pathologies: meningioma (n=16), chordoma (n = 3), schwannoma (n = 3), pituitary adenoma (n = 2), metastasis (n = 3), hemangioblastoma (n = 1), craniopharyngioma (n = 1), and nasopharyngeal tumors (n = 2). Surgical approaches included expanded endonasal approach (n = 19), endoscopic brain port (n = 3), supraorbital "eyebrow" craniotomy (n = 3), retrosigmoid suboccipital craniotomy (n = 3), pterional craniotomy (n = 1), extreme far lateral (n = 1), and laminectomy (n = 1). Successful tumor resection was achieved in 30 cases. Instrument failure was noted in only one extremely fibrous meningioma. The design of this instrument facilitated maneuvering through narrow corridors while providing direct visualization of the suction aperture during tumor resection. These features allowed for tumor removal without injury to adjacent neurovascular structures. The side-cutting aspiration device allows safe and effective tumor removal. Its low profile, variable aspiration, and lack of thermal heat energy are particularly useful in tumor resection through narrow corridors, such as endonasal, port, and keyhole approaches. The multifunctional nature of the instrument (suction, scissors, and dissectors) minimizes multiple exchanges, facilitating tumor resection through these minimal access corridors.

Outcomes of different surgical procedures in the treatment of spinal tuberculosis in adults

OBJECTIVE

To investigate surgical methods and outcomes in the treatment of spinal tuberculosis (TB) in adults.

SUBJECTS AND METHODS

One hundred and eighty-one patients (average age 39 years) without multiple-level noncontiguous spinal TB were followed up for 22-72 months. The patients were divided into four groups according to surgical procedure on the basis of the position and extension of the foci: group A (74 cases): anterior radical debridement and strut grafting with instrumentation; group B (83 cases): posterior instrumentation and bone grafting with anterior radical debridement and strut grafting in a single- or two-stage procedure; group C (10 cases): extrapleural anterolateral decompression and strut grafting with posterior instrumentation in thoracic or thoracolumbar spine, and group D (27 cases): single-stage transforaminal decompression and posterior instrumentation and fusion.

RESULTS

There was a significant decrease (p < 0.05) in mean preoperative (81%) Oswestry's Disability Index. Except for 24 patients with lumbosacral TB who were only instrumented posteriorly, kyphosis degrees were corrected by a mean of 11.5° in the anterior instrumentation group and 12.6° in the posterior instrumentation group (p < 0.01). The correction loss was 6.8° in the anterior instrumentation group and 6.1° in the posterior instrumentation group at the last follow-up (p < 0.01).

CONCLUSION

The four surgical procedures obtained good results for correction and maintenance of the correction, clearance of the foci, decompression of the spinal cord and pain relief in the treatment of spinal TB in adults, providing that the operative indication is accurately identified. However, the posterior approach was superior to anterior instrumentation for correcting deformity and maintaining the correction.

Adjunctive effect of chlorhexidine antiseptics in mechanical periodontal treatment: first results of a preliminary case series

OBJECTIVES

The aim of the present case series was to evaluate the clinical and microbiological effects of a single session of mechanical and manual scaling and root planing (SRP) combined with the use of two different chlorhexidine formulations in the treatment for generalized chronic periodontitis.

METHODS

Ten patients affected by chronic periodontal disease with periodontal probing depth (PPD) ≥ 5 mm were treated with SRP plus local chlorhexidine. In each patient, similar teeth, treated with SRP with the adjunctive use of chlorhexidine digluconate and dihydrochloride or chlorhexidine gluconate, respectively, were selected and assigned to a test and a control group. In both groups, PPD, bleeding on probing (BOP) parameters, total bacterial counts (TBC) and quality of periodontal bacteria at time 0 and 6 weeks after treatment were measured.

RESULTS

PPD significantly decreased over time both in the test and in the control group; however, no significant differences between the two groups were observed. BOP and TBC were significantly lower in the test than in the control group 6 weeks after treatment. In the post-treatment revaluation, a significant decrease both in the treatment and in the control group, for each of the single periodontal pathogens, was observed.

CONCLUSION

In this study--a preliminary case series with small sample size and short follow-up--the adjunctive use of chlorhexidine (CHX) to SRP resulted in clinical and microbiological benefits in the treatment for generalized chronic periodontitis. A CHX gel formulation consisting of CHX digluconate and CHX dihydrochloride seems to lead some additional benefits over SRP plus CHX gluconate in the short term. Additional investigations are needed to evaluate the effectiveness of this antiseptic therapy.

Dynamic nuclear polarization at 700 MHz/460 GHz

We describe the design and implementation of the instrumentation required to perform DNP-NMR at higher field strengths than previously demonstrated, and report the first magic-angle spinning (MAS) DNP-NMR experiments performed at (1)H/e(-) frequencies of 700 MHz/460 GHz. The extension of DNP-NMR to 16.4 T has required the development of probe technology, cryogenics, gyrotrons, and microwave transmission lines. The probe contains a 460 GHz microwave channel, with corrugated waveguide, tapers, and miter-bends that couple microwave power to the sample. Experimental efficiency is increased by a cryogenic exchange system for 3.2 mm rotors within the 89 mm bore. Sample temperatures ≤85 K, resulting in improved DNP enhancements, are achieved by a novel heat exchanger design, stainless steel and brass vacuum jacketed transfer lines, and a bronze probe dewar. In addition, the heat exchanger is preceded with a nitrogen drying and generation system in series with a pre-cooling refrigerator. This reduces liquid nitrogen usage from >700 l per day to <200 l per day and allows for continuous (>7 days) cryogenic spinning without detrimental frost or ice formation. Initial enhancements, ε=-40, and a strong microwave power dependence suggests the possibility for considerable improvement. Finally, two-dimensional spectra of a model system demonstrate that the higher field provides excellent resolution, even in a glassy, cryoprotecting matrix.

Manual sonic-air and ultrasonic instrumentation of root canal and irrigation with 5.25% sodium hypochlorite and 17% Ethylenediaminetetraacetic acid: A scanning electron microscope study

Objectives:

The objective of this study was to evaluate the effectiveness of manual, sonic-air and ultrasonic instrumentation with varying irrigation protocols on removal of the smear layer from root canal walls.

Study Design:

Sixty extracted single rooted human teeth stored in 0.5% saline were used. Periodontal soft tissues were removed followed by crown separation at the cementoenamel junction (CEJ). All the teeth were randomly divided into three groups. Group I was manually instrumented and irrigated with 5.25% sodium hypochlorite (NaOCl) alone and 17% Ethylenediaminetetraacetic acid (EDTA) alternately, same as sonically instrumented Group II and ultrasonically instrumented Group III. The controls for all groups were irrigated with saline solution.

Results:

Ultrasonic over the sonic-air and manual technique, and the use of a combination of two different solutions (17% EDTA and 5.25% NaOCl) alternatively yielded better outcome.

Conclusions:

Ultrasonic, sonic-air and manual instrumentation of the root canal and irrigation with combined solutions is effective in removal of the smear layer from the instrumented walls of the root canal.

The AdaptiSPECT Imaging Aperture

In this paper, we present the imaging aperture of an adaptive SPECT imaging system being developed at the Center for Gamma Ray Imaging (AdaptiSPECT). AdaptiSPECT is designed to automatically change its configuration in response to preliminary data, in order to improve image quality for a particular task. In a traditional pinhole SPECT imaging system, the characteristics (magnification, resolution, field of view) are set by the geometry of the system, and any modification can be accomplished only by manually changing the collimator and the distance of the detector to the center of the field of view. Optimization of the imaging system for a specific task on a specific individual is therefore difficult. In an adaptive SPECT imaging system, on the other hand, the configuration can be conveniently changed under computer control. A key component of an adaptive SPECT system is its aperture. In this paper, we present the design, specifications, and fabrication of the adaptive pinhole aperture that will be used for AdaptiSPECT, as well as the controls that enable autonomous adaptation.

Romero-Troncoso R, Guevara-Gonzalez RG, Millan-Almaraz JR. Instrumentation in developing chlorophyll fluorescence biosensing: a review

Chlorophyll fluorescence can be defined as the red and far-red light emitted by photosynthetic tissue when it is excited by a light source. This is an important phenomenon which permits investigators to obtain important information about the state of health of a photosynthetic sample. This article reviews the current state of the art knowledge regarding the design of new chlorophyll fluorescence sensing systems, providing appropriate information about processes, instrumentation and electronic devices. These types of systems and applications can be created to determine both comfort conditions and current problems within a given subject. The procedure to measure chlorophyll fluorescence is commonly split into two main parts; the first involves chlorophyll excitation, for which there are passive or active methods. The second part of the procedure is to closely measure the chlorophyll fluorescence response with specialized instrumentation systems. Such systems utilize several methods, each with different characteristics regarding to cost, resolution, ease of processing or portability. These methods for the most part include cameras, photodiodes and satellite images.

A 250 GHz gyrotron with a 3 GHz tuning bandwidth for dynamic nuclear polarization

We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementing a long (23 mm) interaction cavity that can excite higher order axial modes by changing either the magnetic field of the gyrotron or the cathode potential. This interaction cavity excites the rotating TE(₅,₂,q) mode, and an internal mode converter outputs a high-quality microwave beam with >94% Gaussian content. The gyrotron was integrated into a DNP spectrometer, resulting in a measured DNP enhancement of 54 on the membrane protein bacteriorhodopsin.

A novel instrumentation circuit for electrochemical measurements

In this paper, a novel signal processing circuit which can be used for the measurement of H⁺ ion and urea concentration is presented. A potentiometric method is used to detect the concentrations of H⁺ ions and urea by using H⁺ ion-selective electrodes and urea electrodes, respectively. The experimental data shows that this measuring structure has a linear pH response for the concentration range within pH 2 and 12, and the dynamic range for urea concentration measurement is in the range of 0.25 to 64 mg/dL. The designed instrumentation circuit possesses a calibration function and it can be applied to different sensing electrodes for electrochemical analysis. It possesses the advantageous properties of being multi-purpose, easy calibration and low cost.

On Advanced Estimation Techniques for Exoplanet Detection and Characterization Using Ground-based Coronagraphs

The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

Fourth-generation spinal instrumentation: experience with adolescent idiopathic scoliosis at a tertiary care hospital in Pakistan

Objective

To evaluate the radiological and functional outcome of surgical treatment of adolescent idiopathic scoliosis using fourth-generation posterior spinal instrumentation at The Aga Khan University, Karachi, Pakistan.

Design

Case series.

Place and duration of study

The Aga Khan University Hospital after a minimum of 2 years postoperatively.

Patients and methods

A total of 20 patients with adolescent idiopathic scoliosis were recruited into the study and evaluated for radiological and functional outcome. The study period was from 2000 to 2005. Radiological outcome was assessed using Cobb angle measurement pre and postoperatively, hence assessing percentage correction. The lower instrumented vertebra was taken as the neutral vertebra and the level was recorded. Functional outcome was determined using the Scoliosis Research Society patient administered questionnaire. All patients were called to the clinic and asked to fill in the form. Those patients who were out of the city were mailed the forms and requested via telephone to complete and return.

Results

Of the 20 patients operated on, twelve were female and eight were male. The average age at operation was 12.7 years. The mean Cobb angle was 69° preoperatively and 20° postoperatively, representing a percentage correction of 71%. The average duration of follow-up was 3.6 years. There was one major complication involving neurological injury post-op and two minor complications involving wound infection. The average Scoliosis Research Society score (on a scale of 1–5, with 5 being best) for pain was 4.5, self-image was 4.2, functional status was 4.1, mental status was 3.8, and satisfaction was 4.4. There was no relationship between the percentage correction of scoliosis and the functional outcome. Those patients with a high preoperative Cobb angle tended to have a better outcome for functional and mental status postoperatively. There was no relation between the lower instrumented vertebra and functional outcome.

Conclusion

In the correct indications, fourth-generation posterior instrumentation and fusion is a reliable and satisfactory technique to treat adolescent idiopathic scoliosis.

Flow cytometry: retrospective, fundamentals and recent instrumentation

Flow cytometry is a complete technology given to biologists to study cellular populations with high precision. This technology elegantly combines sample dimension, data acquisition speed, precision and measurement multiplicity. Beyond the statistical aspect, flow cytometry offers the possibility to physically separate sub-populations. These performances come from the common endeavor of physicists, biophysicists, biologists and computer engineers, who succeeded, by providing new concepts, to bring flow cytometry to current maturity. The aim of this paper is to present a complete retrospective of the technique and remind flow cytometry fundamentals before focusing on recent commercial instrumentation.

Surgical site infection after pediatric spinal deformity surgery

The incidence of surgical site infection (SSI) after spinal deformity surgery for adolescent idiopathic scoliosis ranges from 0.5-6.7%. The risk of infection following spinal fusion in patients with neuromuscular scoliosis is greater, with reported rates of 6.1-15.2% for cerebral palsy and 8-41.7% for myelodysplasia. SSIs result in increased patient morbidity, multiple operations, prolonged hospital stays, and significant financial costs. Recent literature has focused on elucidating the most common organisms involved in SSIs, as well as identifying modifiable risk factors and prevention strategies that may decrease the rates of infection. These include malnutrition, positive urine cultures, antibiotic prophylaxis, surgical site antisepsis, antibiotic-loaded allograft, local application of antibiotics, and irrigation solutions. Acute and delayed SSIs are managed differently. Removal of instrumentation is required for effective treatment of delayed SSIs. This review article examines the current literature on the prevention and management of SSIs after pediatric spinal deformity surgery.

Spine surgery in geriatric patients: Sometimes unnecessary, too much, or too little

Background:

Although the frequency of spinal surgical procedures has been increasing, particularly in patients of age 65 and over (geriatric), multiple overlapping comorbidities increase their risk/complication rates. Nevertheless, sometimes these high-risk geriatric patients are considered for “unnecessary”, too much (instrumented fusions), or too little [minimally invasive surgery (MIS)] spine surgery.

Methods:

In a review of the literature and reanalysis of data from prior studies, attention was focused on the increasing number of operations offered to geriatric patients, their increased comorbidities, and the offers for “unnecessary” spine fusions, including both major open and MIS procedures.

Results:

In the literature, the frequency of spine operations, particularly instrumented fusions, has markedly increased in patients of age 65 and older. Specifically, in a 2010 report, a 28-fold increase in anterior discectomy and fusion was observed for geriatric patients. Geriatric patients with more comorbid factors, including diabetes, hypertension, coronary artery disease (prior procedures), depression, and obesity, experience higher postoperative complication rates and costs. Sometimes “unnecessary”, too much (instrumented fusions), and too little (MIS spine) surgeries were offered to geriatric patients, which increased the morbidity. One study observed a 10% complication rate for decompression alone (average age 76.4), a 40% complication rate for decompression/limited fusion (average age 70.4), and a 56% complication rate for full curve fusions (average age 62.5).

Conclusions:

Increasingly, spine operations in geriatric patients with multiple comorbidities are sometimes “unnecessary”, offer too much surgery (instrumentation), or too little surgery (MIS).

University multi-user facility survey-2010

Multi-user facilities serve as a resource for many universities. In 2010, a survey was conducted investigating possible changes and successful characteristics of multi-user facilities, as well as identifying problems in facilities. Over 300 surveys were e-mailed to persons identified from university websites as being involved with multi-user facilities. Complete responses were received from 36 facilities with an average of 20 years of operation. Facilities were associated with specific departments (22%), colleges (22%), and university research centers (8.3%) or were not affiliated with any department or college within the university (47%). The five most important factors to succeed as a multi-user facility were: 1) maintaining an experienced, professional staff in an open atmosphere; 2) university-level support providing partial funding; 3) broad client base; 4) instrument training programs; and 5) an effective leader and engaged strategic advisory group. The most significant problems were: 1) inadequate university financial support and commitment; 2) problems recovering full service costs from university subsidies and user fees; 3) availability of funds to repair and upgrade equipment; 4) inability to retain highly qualified staff; and 5) unqualified users dirtying/damaging equipment. Further information related to these issues and to fee structure was solicited. Overall, there appeared to be a decline in university support for facilities and more emphasis on securing income by serving clients outside of the institution and by obtaining grants from entities outside of the university.

A narrative review of manual muscle testing and implications for muscle testing research

OBJECTIVE

Manual muscle testing (MMT) is used for a variety of purposes in health care by medical, osteopathic, chiropractic, physical therapy, rehabilitation, and athletic training professionals. The purpose of this study is to provide a narrative review of variations in techniques, durations, and forces used in MMT putting applied kinesiology (AK) muscle testing in context and highlighting aspects of muscle testing important to report in MMT research.

METHOD

PubMed, the Collected Papers of the International College of Applied Kinesiology-USA, and related texts were searched on the subjects of MMT, maximum voluntary isometric contraction testing, and make/break testing. Force parameters (magnitude, duration, timing of application), testing variations of MMT, and normative data were collected and evaluated.

RESULTS

"Break" tests aim to evaluate the muscle's ability to resist a gradually increasing pressure and may test different aspects of neuromuscular control than tests against fixed resistances. Applied kinesiologists use submaximal manual break tests and a binary grading scale to test short-term changes in muscle function in response to challenges. Many of the studies reviewed were not consistent in reporting parameters for testing.

CONCLUSIONS

To increase the chances for replication, studies using MMT should specify parameters of the tests used, such as exact procedures and instrumentation, duration of test, peak force, and timing of application of force.

Instrumentation in endourology

Success with endourological procedures requires expertise and instrumentation. This review focuses on the instrumentation required for ureteroscopy and percutaneous nephrolithotomy, and provides a critical assessment of in vitro and clinical studies that have evaluated the comparative effectiveness of these medical devices.

Microwave field distribution in a magic angle spinning dynamic nuclear polarization NMR probe

We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B(1S)) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4mm diameter sapphire rotor containing the sample. The predicted average B(1S) field is 13μT/W(1/2), where S denotes the electron spin. For a routinely achievable input power of 5W the corresponding value is γ(S)B(1S)=0.84MHz. The calculations provide insights into the coupling of the microwave power to the sample, including reflections from the RF coil and diffraction of the power transmitted through the coil. The variation of enhancement with rotor wall thickness was also successfully simulated. A second, simplified calculation was performed using a single pass model based on Gaussian beam propagation and Fresnel diffraction. This model provided additional physical insight and was in good agreement with the full HFSS simulation. These calculations indicate approaches to increasing the coupling of the microwave power to the sample, including the use of a converging lens and fine adjustment of the spacing of the windings of the RF coil. The present results should prove useful in optimizing the coupling of microwave power to the sample in future DNP experiments. Finally, the results of the simulation were used to predict the cross effect DNP enhancement (ϵ) vs. ω(1S)/(2π) for a sample of (13)C-urea dissolved in a 60:40 glycerol/water mixture containing the polarizing agent TOTAPOL; very good agreement was obtained between theory and experiment.

Screening for domestic violence in Jordan: validation of an Arabic version of a domestic violence against women questionnaire

OBJECTIVES

Abuse against women causes a great deal of suffering for the victims and is a major public health problem. Measuring lifetime abuse is a complicated task; the various methods that are used to measure abuse can cause wide variations in the reported occurrences of abuse. Furthermore, the estimated prevalence of abuse also depends on how abuse is culturally defined. Researchers currently lack a validated Arabic language instrument that is also culturally tailored to Arab and Middle Eastern populations. Therefore, it is important to develop and evaluate psychometric properties of an Arabic language version of the newly developed NorVold Domestic Abuse Questionnaire (NORAQ).

DESIGN AND METHODS

The five core elements of the NORAQ (emotional abuse, physical abuse, sexual abuse, current suffering of the abuse, and communication of the history of abuse to the general practitioner) were translated into Arabic, translated back into English, and pilot tested to ensure cultural sensitivity and appropriateness for adult women in the Eastern Mediterranean region. Participants were recruited from the Jordanian Ministry of Health-Maternal and Child Health Care Centers in two large cities in Jordan.

RESULTS

A self administered NORAQ was completed by 175 women who had attended the centers. The order of factors was almost identical to the original English and Swedish languages questionnaire constructs. The forced 3-factor solution explained 64.25% of the variance in the measure. The alpha reliability coefficients were 0.75 for the total scale and ranged from 0.75 to 0.77 for the subscales. In terms of the prevalence of lifetime abuse, 39% of women reported emotional abuse, 30% physical abuse, and 6% sexual abuse.

CONCLUSION

The Arabic version of the NORAQ has demonstrated initial reliability and validity. It is a cost-effective means for screening incidence and prevalence of lifetime domestic abuse against women in Jordan, and it may be applicable to other Middle East countries.

Combined passive detection and ultrafast active imaging of cavitation events induced by short pulses of high-intensity ultrasound

The activation of natural gas nuclei to induce larger bubbles is possible using short ultrasonic excitations of high amplitude, and is required for ultrasound cavitation therapies. However, little is known about the distribution of nuclei in tissues. Therefore, the acoustic pressure level necessary to generate bubbles in a targeted zone and their exact location are currently difficult to predict. To monitor the initiation of cavitation activity, a novel all-ultrasound technique sensitive to single nucleation events is presented here. It is based on combined passive detection and ultrafast active imaging over a large volume using the same multi-element probe. Bubble nucleation was induced using a focused transducer (660 kHz, f-number = 1) driven by a high-power electric burst (up to 300 W) of one to two cycles. Detection was performed with a linear array (4 to 7 MHz) aligned with the single-element focal point. In vitro experiments in gelatin gel and muscular tissue are presented. The synchronized passive detection enabled radio-frequency data to be recorded, comprising high-frequency coherent wave fronts as signatures of the acoustic emissions linked to the activation of the nuclei. Active change detection images were obtained by subtracting echoes collected in the unnucleated medium. These indicated the appearance of stable cavitating regions. Because of the ultrafast frame rate, active detection occurred as quickly as 330 μs after the high-amplitude excitation and the dynamics of the induced regions were studied individually.

Development and validation of an instrument for rapidly assessing symptoms: the general symptom distress scale

CONTEXT

Symptom assessment has increasingly focused on the evaluation of total symptom distress or burden rather than assessing only individual symptoms. The challenge for clinicians and researchers alike is to assess symptoms, and to determine the symptom distress associated with the symptoms and the patient's ability for symptom management without a lengthy and burdensome assessment process.

OBJECTIVES

The objective of this article was to discuss the psychometric evaluation of a brief general symptom distress scale (GSDS) developed to assess specific symptoms and how they rank in relation to each other, the overall symptom distress associated with the symptom schema, and provide an assessment of how well or poorly that symptom schema is managed.

METHODS

Results from a pilot study about the initial development of the GSDS with 76 hospitalized patients are presented, followed by a more complete psychometric evaluation of the GSDS using three samples of cancer patients (n=190) and their social network members, called partners in these studies (n=94). Descriptive statistics were used to describe the GSDS symptoms, symptom distress, and symptom management. Point biserial correlations indexed the associations between dichotomous symptoms and continuous measures, and conditional probabilities were used to illustrate the substantial comorbidities of this sample. Internal consistency was examined using the KR-20 coefficient, and test-retest reliability was examined. Construct validity and predictive validity also were examined.

RESULTS

The GSDS demonstrated satisfactory internal consistency and test-retest reliability, and good construct validity and predictive validity. The total score on the GSDS, symptom distress, and symptom management correlated significantly with related constructs of depression, positive and negative affect, and general health. The GSDS was able to demonstrate its ability to distinguish between those with or without chronic illness, and was able to significantly predict scores on criterion measures such as depression.

CONCLUSION

Collectively, these results suggest that the GSDS is a straightforward and useful instrument for rapidly assessing symptoms that can disrupt health-related quality of life.

The incidence and cost of devices explanted during single-level anterior diskectomy/fusions

BACKGROUND

Little is known about the costs of devices explanted during anterior cervical diskectomy and fusion surgery. This retrospective study analyzes the costs to a single hospital of plates, screws and spacers used in all single-level anterior diskectomy and fusion (single-ADF) operations performed during a 1-year period.

MATERIALS AND METHODS

Our objective was to determine the costs of instrumentation explanted (i.e. implanted during surgery but removed prior to closure) during 87 single-ADF procedures performed at a single institution within a single year, 2009. All 87 single-ADF procedures were analyzed to determine the frequency and costs (without overhead) to the hospital for both permanently implanted and explanted anterior cervical screws, plates, and spacers (allograft, artificial plastics, and cages). All patients undergoing single-ADF were included in this study irrespective of the diagnosis related group (DRG) category.

RESULTS

THE COSTS, WITHOUT OVERHEAD TO THE HOSPITAL, FOR THE PERMANENTLY IMPLANTED INSTRUMENTATION WERE: screws ($103,572: 84 patients); plates ($120,694: 85 patients); allograft spacers ($92,776: 64 patients); cages ($38,821: 9 patients); and autografts (no charge; 14 patients), for a total of $355,863. The additional costs to the hospital for explanted instrumentation were: 37 screws ($11,014: 17 patients); 7 plates ($12,743: 5 patients); and 8 allograft spacers ($9093: 7 patients); there were no explanted cages. The total cost of the explanted devices was $32,850.

CONCLUSIONS

During 87 single-ADF procedures, a total of 37 screws, 7 plates, and 8 spacers were explanted in 24 (27.6%) patients, resulting in an additional $32,850, 9.2%, to the cost of the implanted devices.

Evaluation of the Bruker SMART X2S: crystallography for the nonspecialist?

An evaluation of the Bruker SMART X2S for the collection of crystallographic diffraction data, structure solution and refinement is carried out with a variety of materials with different electron densities, presenting some of the successes and challenges of automation in chemical crystallography.

Update on ureteroscopy instrumentation

The authors present an objective review of what is new in endourology instrumentation, based on up-to-date scientific data gathered from meetings, state-of-art lectures and current literature. The main scope of this review is to highlight the most recommended device options for each step of an ureteroscopy, in order to offer best care to patients.

Video-assisted thoracoscopic surgery for correction of adolescent idiopatic scoliosis: comparison of 4.5 mm versus 5.5 mm rod constructs

PURPOSE

The purpose of this study is to report the comparative results of thoracoscopic correction achieved via cantilever technique using a 4.5 mm thin rod and the poly-axial reduction screw technique using a 5.5 mm thick rod in Lenke type 1 adolescent idiopathic scoliosis (AIS).

MATERIALS AND METHODS

Radiographic data, Scoliosis Research Society (SRS) patient-based outcome questionnaires, and operative records were reviewed for forty-nine patients undergoing surgical treatment of scoliosis. The study group was divided into a 4.5 mm thin rod group (n = 24) and a 5.5 mm thick rod group (n = 25). The radiographic parameters that were analyzed included coronal curve correction, the most caudal instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis.

RESULTS

The major curve was corrected from 49.8 degrees and 47.2 degrees pre-operatively to 24.5 degrees and 18.8 degrees at the final follow-up for the thin and thick rod groups, respectively (50.8% vs. 60.2% correction). There were no significant differences between the two groups in terms of kyphosis, coronal balance, or tilt angle at the time of the final follow-up. The mean number of levels fused was 6.2 in the thin rod group, compared with 5.9 levels in the thick rod group. There were no major intraoperative complications in either group.

CONCLUSION

Significant correction loss was observed in the thin rod system at the final follow-up though both groups had comparable correction immediately post-operative. Therefore, the thick rod with poly axial screw system helps to maintain post-operative correction.

Cost-effectiveness of image-guided spine surgery

Objective:

To determine if image-guided spine surgery is cost effective.

Methods:

A prospective case series of the first 100 patients undergoing thoracolumbar pedicle screw instrumentation under image-guidance was compared to a retrospective control group of the last 100 patients who underwent screw placement prior to the use of image-guidance. The image-guidance system was NaviVision (Vector Vision-BrainLAB) and Arcadis Orbic (Siemens).

Results:

The rate of revision surgery was reduced from 3% to 0% with the use of image guidance (p=0.08). The cost savings of image guidance for the placement of pedicle screws was $71,286 per 100 cases. Time required for pedicle screw placement with image guidance was 20 minutes for 2 screws, 29 minutes for 4 screws, 38 minutes for 6 screws, and 50 min for 8 screws. Cost savings for the time required for placement of pedicle screws with image guidance can be estimated by subtracting the time required with currently used techniques without image guidance from the above averages, then multiplying by $93 per minute. The approximate costs of the navigation system is $475,000 ( $225,000 for Vector Vision-BrainLAB and $250,000 for Arcadis Orbic-Siemens).

Conclusion:

Image guidance for the placement of pedicle screws may be cost effective in spine practices with heavy volume, that perform surgery in difficult cases, and that require long surgical times for the placement of pedicle screws.

Robotic instrumentation: Evolution and microsurgical applications

This article presents a review of the history and evolution of robotic instrumentation and its applications in urology. A timeline for the evolution of robotic instrumentation is presented to better facilitate an understanding of our current-day applications. Some new directions including robotic microsurgical applications (robotic assisted denervation of the spermatic cord for chronic orchialgia and robotic assisted vasectomy reversal) are presented. There is a paucity of prospective comparative effectiveness studies for a number of robotic applications. However, right or wrong, human nature has always led to our infatuation with the concept of using tools to meet our needs. This chapter is a brief tribute to where we have come from and where we may be potentially heading in the field of robotic assisted urologic surgery.

Probes for high field solid-state NMR of lossy biological samples

In solid-state NMR hydrated samples of biopolymers are susceptible to radio frequency heating and have a significant impact on probe tuning frequency and performance parameters such as sensitivity. These considerations are increasingly important as magnetic field strengths increase with improved magnet technology. Recent developments in the design, construction, and performance of probes for solid-state NMR experiments on stationary lossy biological samples at high magnetic fields are reviewed.