Standard Insertion Research Articles

Disposable laryngeal tube suction: Standard insertion technique versus two modified insertion techniques for patients with a simulated difficult airway

Objective The disposable laryngeal tube suction (LTS-D) is a supraglottic airway device that can be used as an alternative to tracheal tube to provide ventilation. We tested the hypothesis that, with a frontal jaw thrust insertion technique (FIT/JT), the rate of correct placement attempts in patients with a simulated difficult airway by means of a rigid cervical immobilization collar could be significantly increased compared to the standard insertion technique (SIT) recommended by the manufacturer. Methods 70 adult patients undergoing trauma surgery under general anaesthesia had an LTS-D inserted, randomly assigned to the SIT or FIT/JT. In the FIT/JT, the operator was standing in front of the patient's head, and forced chin lift to create sufficient retropharyngeal space was performed. The rate of successful tube placements within 180 s and with a maximum of two attempts was the main outcome variable. To distinguish between the effects of the frontal approach and the jaw thrust manoeuvre, a third group was studied after completion of the SIT and FIT/JT groups. The standard insertion technique, but with a jaw thrust manoeuvre (SIT/JT), was employed in another 35 consecutive patients. Results Overall placement success was 49% (SIT, 17/35 patients, P < 0.001), 91% (SIT/JT, 32/35 patients) and 100% (FIT/JT). The time required for successful insertion was shortest in the FIT/JT group (23 ± 6 s), and significantly longer in the SIT/JT (42 ± 29 s, P < 0.001) and SIT groups (51 ± 29 s, P < 0.0001). Conclusion In anaesthetised patients with a simulated difficult airway created with a rigid cervical collar, the overall LTS-D placement success was significantly higher when a jaw thrust manoeuvre was performed, regardless of the particular technique used to introduce the LTS-D. Therefore, an intense jaw thrust manoeuvre should be performed whenever an LTS-D is being inserted.

Influence of the insert design on clinical results and kinematics of the knee after total knee arthroplasty

To investigate the influence of the insert design of knee prosthesis on clinical results and kinematics of the knee after total knee arthroplasty (TKA). Forty-two knees in 28 patients with knee osteoarthritis undergoing TKA using the GENESIS II from July 2007 to June 2009 were included in this study, mean follow-up of 27.7 months. The cases were divided into 2 groups according to the type of insert, one was high flexion insert group (23 knees) and the other was standard insert group (19 knees). Two groups were compared by clinical ratings of knee function. The motion of flexion and extension of the two groups was observed by cyclic fluoroscopy and the data was analyzed by mapping software. The influence of the insert design of knee prosthesis on kinematics of the knee after TKA was investigated by comparing the parameters of the two groups during the movement of knee joint, including femoral roll back and extensor mechanism arm. The range of motion of standard insert group and high flexion insert group was 120° and 123° respectively with no difference between them. There was no difference of knee society clinical rating system in both groups. Feller score of high flexion insert group was higher than the standard insert group, the difference was significant statistically (P = 0.012). In the imaging measurement, the two groups had no differences in femoral rollback and extensor mechanism arm during the 0 to 120° range of movement. The two groups appeared significant statistically (P = 0.034) in the extensor mechanism arm when flexion extended to 130°. The high flexion improved design may play a certain role on reducing anterior knee pain and improving knee function after TKA. However, the improved design may be reduced the extensor mechanism arm when high flexion, so that affecting the work ability of quadriceps.

Can High-Flexion Tibial Inserts Improve Range of Motion After Posterior Cruciate-Retaining Total Knee Arthroplasty?

Interest in high-flexion total knee arthroplasty (TKA) prostheses designed to provide better postoperative range of motion (ROM) is widespread. We sought to determine whether changes in surface geometry of the tibial polyethylene insert could improve postoperative ROM in a consecutive series of patients undergoing TKA with retention of the posterior cruciate ligament (PCL). Two cohorts with Smith & Nephew (Memphis, Tennessee) Posterior Cruciate-Retaining Genesis II total knee prostheses were compared, 79 knees (65 patients) using standard tibial inserts and 85 knees (72 patients) using high-flexion inserts. The standard insert has a slightly raised posterior lip, whereas the high-flexion insert is recessed downward at the posterior margin to facilitate femoral rollback in flexion and eliminate impingement of the femoral component on the back of the polyethylene during rollback. Mean ROM 1 year postoperatively was 112.0° in patients receiving the standard insert and 119.3° in patients receiving the high-flexion insert. Preoperative ROM was similar in both groups. Flexion improvement in the high-flexion group over the standard insert group was statistically significant (P<.001). Final Knee Society Scores did not differ amongst patients receiving the standard and high-flexion inserts. Our study demonstrates that improved postoperative flexion can be achieved without changing surgical technique, bony cuts, or metallic prosthetic parts. This is the first report that we are aware of that documents improvement in ROM after PCL-retaining TKA through the use of high-flexion inserts.

Design of form milling cutters with multiple inserts for screw rotors

Form milling cutters with multiple inserted cutter blades are widely used in roughing screw rotors. This paper proposes a mathematical method for finding the distribution of cutter body inserts that will result in an equal wear rate for their cutting edges. First, commercially available standard inserts are selected and positioned in the form milling cutter axial section to satisfy profile geometry tolerance. Next, the insert tool life in every position is estimated based on its cutting material volume and corresponding wear rates. To even the insert wear rate and increase tool life, multiple inserts can be used at the same insertion position. Once the numbers of insert positions and inserts at each position have been explicitly defined, the inserts can be distributed on the cutter body periphery in a spiral form. Not only is the operational cost of such form milling cutters far less than that of cutters using special order blades, but the fact that all inserts are chosen from standard blades and can be replaced when the cutting edge becomes dull makes geometric precision easier to maintain.

Therapy for Missing Lower Medial Incisor by Means of Reduced Diameter Implants

S ince Branemark first described the principle of osseointegration in the field of dentistry, dental implantology has become a rapidly evolving and innovative field. In 2004, the American Dental Association Council on Scientific Affairs cited dental implants as the ‘‘first generation of tissue engineering devices that will affect the dental profession.’’ Accordingly, a wide variety of implant materials, shapes, sizes, and surface treatments have been devised. Patients have become aware of the potential of dental implants; prostheses that function immediately are often desired. To meet this demand, implants of increasingly smaller diameter have been devised, and singlestage procedures with immediate functional loading have become available. Small-diameter implants (SDIs) are the preferred treatment modality in cases of limited anatomic geography. These implants range from 2.75–3.3 mm in width and from 8.0–15.0 mm in length. Specifically, SDIs are indicated for replacement of teeth with small cervical diameters and in cases of reduced interradicular bone. They also have been shown to be a viable alternative to bone augmentation when poor alveolar ridge width is encountered and in cases of restricted mesiodistal anatomy. Based on this in vivo and in vitro success, the mini dental implant (MDI) seems a logical successor. Smaller than their SDI counterparts, MDIs have diameters ranging from 1.8– 2.4 mm. MDIs were initially designed for temporary prosthetic stabilization during the healing phase of standard implants. Reproducible success in this indication has led to expanded use in orthodontic anchorage, for the temporary fixation of transplanted teeth, in periodontal therapy, and, more recently, for long-term fixed and removable prosthetics. Although the Sendax MDI (3M ESPE, OsseoSOURCE, St Paul, Minn) was the first MDI to gain approval from the U.S. Food and Drug Administration for long-term applications, several other MDI systems are available, including Hi Tec Implants (Hi Tec Implants, Herzlia, Israel) and Monorail MTI 1 Private dental practice, DEIMPERIO, LLC, Bratislava, Slovak Republic. 2 Department of Stomatology and Maxillofacial Surgery of the Faculty of Medicine, Comenius University and Oncologic Institute of St Elisabeth, Bratislava, Slovak Republic. 3 Private dental practice, DENTALNE CENTRUM, LLC, Trnava, Slovak Republic. 4 Private dental practice, Eurodent Medima, LLC, Martin, Slovak Republic. * Corresponding author, e-mail: richard.jurkovic@chello.sk DOI: 10.1563/AAID-JOI-D-09-00138 CASE LETTER

Impact of a standardized protocol and antibiotic-impregnated catheters on ventriculostomy infection rates in cerebrovascular patients.

Ventriculostomy infections create significant morbidity. To reduce infection rates, a standardized evidence-based catheter insertion protocol was implemented. A prospective observational study analyzed the effects of this protocol alone and with antibiotic-impregnated ventriculostomy catheters. To compare infection rates after implementing a standardized protocol for ventriculostomy catheter insertion with and without the use of antibiotic-impregnated catheters. Between 2003 and 2008, 1961 ventriculostomies and infections were documented. A ventriculostomy infection was defined as 2 positive CSF cultures from ventriculostomy catheters with a concurrent increase in cerebrospinal fluid white blood cell count. A baseline (preprotocol) infection rate was established (period 1). Infection rates were monitored after adoption of the standardized protocol (period 2), institution of antibiotic-impregnated catheter A (period 3), discontinuation of antibiotic-impregnated catheter A (period 4), and institution of antibiotic-impregnated catheter B (period 5). The baseline infection rate (period 1) was 6.7% (22/327 devices). Standardized protocol (period 2) implementation did not change the infection rate (8.2%; 23/281 devices). Introduction of catheter A (period 3) reduced infections to 1.0% (2/195 devices, P=.0005). Because of technical difficulties, this catheter was discontinued (period 4), resulting in an increase in infection rate (7.6%; 12/157 devices). Catheter B (period 5) significantly decreased infections to 0.9% (9 of 1001 devices, P=.0001). The Staphylococcus infection rate for periods 1, 2, and 4 was 6.1% (47/765) compared with 0.2% (1/577) during use of antibiotic-impregnated catheters (periods 3 and 5). The use of antibiotic-impregnated catheters resulted in a significant reduction of ventriculostomy infections and is recommended in the adult neurosurgical population.

Water immersion versus standard colonoscopy insertion technique: randomized trial shows promise for minimal sedation

Water immersion is an alternative colonoscopy technique that may reduce discomfort and facilitate insertion of the instrument. This was a prospective study to compare the success of colonoscopy with minimal sedation using water immersion and conventional air insufflation. A total of 229 patients were randomized to either water immersion or the standard air insertion technique. The primary outcome was success of minimal sedation colonoscopy, which was defined as reaching the cecum without additional sedation, exchange of the adult colonoscope or hands-on assistance for trainees. Patient comfort and satisfaction were also assessed. Successful minimal-sedation colonoscopy was achieved in 51 % of the water immersion group compared with 28 % in the standard air group (OR, 2.66; 95 % CI 1.48 - 4.79; P = 0.0004). Attending physicians had 79 % success with water immersion compared with 47 % with air insufflation (OR, 4.19; 95 % CI 1.5 - 12.17; P = 0.002), whereas trainees had 34 % success with water compared with 16 % using air (OR, 2.75; 95 % CI 1.15 - 6.86; P = 0.01). Using the water method, endoscopists intubated the cecum faster and this was particularly notable for trainees (13.0 +/- 7.5 minutes with water vs. 20.5 +/- 13.9 minutes with air; P = 0.0001). Total procedure time was significantly shorter with water for both experienced and trainee endoscopists ( P < 0.05). Patients reported less intraprocedural pain with water compared with air (4.1 +/- 2.7 vs. 5.3 +/- 2.7; P = 0.001), with a similar level of satisfaction. There was no difference in the neoplasm detection rates between the groups. Colonoscopy insertion using water immersion increases the success rate of minimal sedation colonoscopy. Use of the technique leads to a decrease in discomfort, time to reach the cecum, and the amount of sedative and analgesic used, without compromising patient satisfaction.

Audiological outcome of the pull‐back technique in cochlear implantees

The distance of the cochlear implant electrode contacts to the modiolus can be reduced by a surgical technique called "pull-back." This procedure changes the location of the fully inserted electrode array by moving the electrode out of the cochlea until the first silicon ring is visible in the cochleostomy. This leads to a more focused stimulation, which in turn could possibly improve hearing performance. The objective of the present study was to investigate the influence of the pull-back technique on frequency difference limens (FDL) and speech perception. Double-blind trial. Twelve pull-back and 12 matched controls (matched by age, gender, duration of deafness, and duration of implant use) were used. Twenty-four patients were implanted with the Nucleus-24 Contour Advance array. In 12 patients the pull-back technique was used and in 12 matched controls a standard insertion technique was applied. Twelve months after the initial stimulation speech perception, spread of neuronal excitation (SOE) at electrodes 5, 10, and 15; and FDLs at 1, 2, and 4 kHz were measured. There was no significant difference of speech perception performance between the two groups. However, the mean FDL for the 4 kHz reference tone was significantly lower in the pull-back group compared to the controls. The SOE was significantly reduced at basal, middle, and apical electrodes in the electrode pull-back group. The pull-back technique seems to have its greatest effect on perimodiolar position in the basal regions of the cochlea. Therefore, it is most likely to observe improved FDL in the 4 kHz region. Current speech recognition tests do not reflect the lower FDL.

Effects of cold sphere walls in PET phantom measurements on the volume reproducing threshold

We studied quantitatively the effects of the discontinuity introduced in an otherwise homogeneous background by the cold walls of the standard spherical glass inserts commonly used in phantom measurements for calibration of threshold-based approaches to volumetric evaluation of PET investigations. We concentrated especially on the question of threshold-based volume determination. We computed analytically the convolution of an isotropic Gaussian point-spread function with the insert geometry (hot sphere + cold wall + warm background) and derived the theoretical background dependence of the volume reproducing threshold. This analysis shows a clear wall-related reduction of the optimal threshold with increasing background. The predictions of our theoretical analysis were verified in phantom measurements at background fractions between 0 and 0.29. Defining the background-corrected relative threshold (Tabs: absolute volume reproducing threshold, A: measured activity at centre, B: background), we find that for a wall-less sphere T is independent of the background level. In the presence of cold walls, T drops (for not too small spheres, where recovery at the centre approaches 100%) from about 43% at B/A = 0 to about 25% at B/A = 0.5. Applying these thresholds to wall-less spheres leads to sizeable overestimates of the true volumes (43% at B/A = 0.5 for a sphere of 6 ml volume). We conclude that phantom measurements with standard sphere inserts for calibration of optimal thresholding algorithms introduce a systematic bias if performed at finite background levels. The observed background dependence is an artefact of the measurement procedure and does not reflect the conditions present in actual patient investigations.

Insertion of the ProSeal™ laryngeal mask airway is more successful with the 90° rotation technique

The 90 degrees rotation technique for inserting the ProSeal laryngeal mask airway (PLMA) in anesthetized paralyzed patients was compared with the index finger insertion technique. One hundred twenty Asian adult patients were randomly allocated to either a standard technique group or a rotation technique group. A PLMA size 4 was used for women and size 5 was used for men. In the standard technique group (n = 60), the PLMA was inserted using the index finger. In the rotation technique group (n = 60), the entire cuff of the PLMA was placed in the patient's mouth in a midline approach without finger insertion, rotated 90 degrees counter clockwise around the patient's tongue, advanced and then rotated back until resistance was felt. The primary outcome was success at first insertion. Secondary outcome measures were insertion time and complications. The success rate at first insertion was greater for the rotation technique group than for the standard technique group (100% vs 83%, respectively; P = 0.003), and less time was required (11 +/- 3 sec vs 19 +/- 16 sec, respectively; P = 0.03). The incidence of postoperative sore throat was lower for the rotation technique group than for the standard technique group (12% vs 33%, respectively; P = 0.009), and blood staining on the PLMA was less (8% vs 40%, respectively; P < 0.001). The 90 degrees rotation technique for inserting the PLMA is more successful than the standard index finger insertion technique. It is associated with fewer side effects, such as blood on the PLMA and sore throat, which suggests it causes less pharyngeal trauma.

Range of motion and function are similar in patients undergoing TKA with posterior stabilised and high-flexion inserts.

It is debatable whether high-flexion (HF) total knee arthroplasty (TKA) designs will improve postoperative flexion and function or will diminish the need for manipulation under anaesthesia (MUA). We retrospectively analysed range of motion (ROM), flexion, Knee Society Score (KSS), and rate of MUA in a consecutive group of patients who underwent TKA with a conventional posterior stabilised (PS) insert or an HF insert using identical surgical technique, implant design, and postoperative care. Fifty TKAs with a standard PS insert were matched for patient's age, gender, preoperative ROM, and KSS with 50 TKA performed with an HF insert. The patient's ROM and KSS were evaluated at six weeks, four months, and one year postoperatively. The outcome variables (flexion, ROM, KSS, and manipulation rate) in both groups were compared using the generalised estimating equations method. A second analysis of patients with preoperative flexion ≥120° was performed. The ROM, flexion, and patient-reported KSS was similar in both groups at each time period. The rate of MUA was also similar. Patients with a preoperative ROM of at least 120° showed similar results. Our study found that one year after surgery, patients who underwent TKA with a PS or an HF insert achieved similar flexion, ROM, and function.

Single-Port Laparoscopic Appendicectomy

TECHNIQUE The patient should be prepared as for a standard manipulation and insertion of K-wires. Closed manipulation should attempted. If this is not successful in restoring anatomy, the additional Kwire may be inserted as described below. A 2-cm incision should be made over the medial epicondyle with the elbow extended and deepened to the bone with meticulous attention to preservation of the ulna nerve. A 2-mm (1.6 mm in young children) K-wire should then be inserted from medial to lateral (under X-ray control) passing through the trochlea and through the capitellum. It should then be passed out through the skin to provide a bar: this can be used to provide both traction and torque to the distal fragment allowing reduction to be easily achieved. Once satisfactory reduction is accomplished, traditional crossed K-wires should be passed using the 2-cm wound used for the medial K-wire. The transverse K-wire is now removed leaving the fracture held by the two standard K-wires.

Minimally Invasive Hip Fracture Surgery: Are Outcomes Better?

Intertrochanteric hip fractures have high morbidity and mortality rates. The purpose of this study was to determine if minimally invasive plating, nailing, or external fixation operations lead to improved outcomes for intertrochanteric hip fractures compared with standard insertion of a sliding hip screw (SHS). A systematic search of MEDLINE (1996 to June 2007) and EMBASE (1980 to June 2007) was performed. Results were limited to English language studies. References from eligible studies were reviewed to identify additional studies. Studies were selected for review based on the following criteria: prospective or retrospective studies comparing minimally invasive plating, nailing, or external fixation to standard insertion of an SHS, exclusion of intracapsular and subtrochanteric hip fractures, and report of outcome data by treatment group to allow for comparison. The following outcomes were extracted from eligible studies: operative time, operative blood loss, intraoperative complications, postoperative drop in hemoglobin, postoperative pain, postoperative medical or fracture complications, wound complications, length of hospital stay, and post-fracture function. Sufficient data existed among 14 randomized controlled trials to perform a meta-analysis and calculate pooled relative risks for failure of fixation, blood transfusion, and mortality. Relative risks were calculated with 95% confidence intervals using a random-effects model, and an analysis of heterogeneity between pooled studies was conducted. Other outcome measures that were extracted from 17 comparative studies are reported as a systematic review. Although a significant heterogeneity exists between pooled studies, minimally invasive hip fracture plating, nailing, or external fixation was associated with a decrease in transfusion rate [relative risk of 0.63 as compared to standard SHS (95% confidence interval 0.41 to 0.96; I(2) = 83.6%)]. There was no significant difference for the other comparisons, including mortality between minimally invasive plating, nailing, or external fixation and standard insertion of an SHS.

Investigation of the feasibility of relative 3D dosimetry in the Radiologic Physics Center Head and Neck IMRT phantom using Presage/optical‐CT

This study presents the application of the Presage/optical-CT 3D dosimetry system for relative dosimetry in the Radiologic Physics Center (RPC) Head and Neck (H&N) IMRT phantom. Performance of the system was evaluated by comparison with the "gold-standard" RPC credentialing test. A modified Presage cylindrical insert was created that extended the capability of the RPC H&N phantom to 3D dosimetry. The RPC phantom was taken through the entire treatment planning procedure with both the standard RPC insert and the modified Presage insert. An IMRT plan was created to match the desired dose constraints of the credentialing test. This plan was delivered twice to the RPC phantom: first containing the standard insert, and then again containing the Presage insert. After irradiation, the standard insert was sent for routine credentialing analysis; including point dose measurements (TLD) and planar Gafchromic EBT film measurement. The 3D dose distribution from Presage was read out at Duke using the OCTOPUS 5X optical-CT scanner. The Presage distribution was compared with gold-standard EBT measurement (determined by the RPC) and the calculated Eclipse distribution. The agreement between the normalized EBT, Presage, and Eclipse distributions, in the central axial plane was evaluated using profiles and gamma-map comparisons (4% dose difference and 3 mm distance to agreement). Profiles showed good agreement between EBT, Presage, and Eclipse distributions. 2D gamma-map comparisons between all three modalities showed at least 98% pass rate. The excellent agreement between Presage and EBT in the central plane established Presage as a standard against which to evaluate the accuracy of the 3D calculated Eclipse distribution. A gamma comparison between normalized Presage and Eclipse 3D distributions gave an overall pass rate of approximately 94%. In conclusion, the Presage/optical-CT system was found to be feasible for relative 3D dosimetry in the RPC IMRT H&N phantom. The potential to extend the RPC IMRT credentialing procedure to 3D may be feasible provided accurate calibration to dose (Gy) and robustness to shipping stress are demonstrated.

MO‐FF‐A4‐03: Testing of the High‐Resolution ROI Micro‐Angio Fluoroscope (MAF) Detector Using a Modified NEMA XR‐21 Phantom

Purpose: To test the MAF in conditions and tasks specific to minimally invasive neurovascular procedures. Materials and Methods: A high‐sensitivity, high‐resolution MAF detector was built and incorporated into a standard angiographic C‐Arm system. This detector consists of a 300μm CsI input phosphor coupled to a dual stage GEN2 micro‐channel‐plate light image intensifier, followed by minifying fiber‐optic taper coupled to a CCD chip. The detector is attached to a very stable detector‐changer onto a Flat‐Panel (FP) C‐arm angiographic unit to allow facile placement of the detector into the field‐of‐view whenever high resolution is needed. A NEMA XR21‐2000 phantom was modified to evaluate neurovascular x‐ray imaging systems. The phantom was restructured to be head‐equivalent; two aluminum plates shaped to fit into the NEMA phantom geometry were added to a 15cm thick section. Digital subtraction angiography (DSA) testing was enabled by adding a removable central section with a hollow slot which allows insertion of various angiographic test blocks. DSA and DA were tested using a standard removable insert having simulated arteries with thicknesses of 4, 2 and 1 mm and 15mg/cm3 iodine contrast and with stenoses and aneurysms (AAPM Report 15). Features on the central plates of the NEMA XR21 phantom such as bar pattern and iodine‐detail‐contrast‐targets were also imaged. The results of the evaluation of the MAF with the modified phantom were compared with the images obtained with a standard flat panel. Results: The phantom imaging results presented as (MAF‐detected‐features/Flat‐Panel‐detected‐features) are: bar pattern — (5.0/3.1) lines/mm; smallest iodine‐contrast target group detectable — (10/10) mg/cm2, details of smallest simulated vessel in DSA — (1/2) mm. Conclusions: The MAF detector performs at least as well as a standard FP in detection of low‐contrast objects, and is superior in the visualization and identification of the small details. (Support: NIH grant R01‐EB002873, R01EB0008425).

Investigating the feasibility of 3D dosimetry in the RPC IMRT H&N phantom

An urgent requirement for 3D dosimetry has been recognized because of high failure rate (∼25%) in RPC credentialing, which relies on point and 2D dose measurements. Comprehensive 3D dosimetry is likely to resolve more errors and improve IMRT quality assurance. This work presents an investigation of the feasibility of PRESAGE/optical-CT 3D dosimetry in the Radiologic Physics Center (RPC) IMRT H&N phantom. The RPC H&N phantom (with standard and PRESAGE dosimetry inserts alternately) was irradiated with the same IMRT plan. The TLD and EBT film measurement data from standard insert irradiation was provided by RPC. The 3D dose measurement data from PRESAGE insert irradiation was readout using the OCTOPUS™ 5X optical-CT scanner at Duke. TLD, EBT and PRESAGE dose measurements were inter-compared with Eclipse calculations to evaluate consistency of planning and delivery. Results showed that the TLD point dose measurements agreed with Eclipse calculations to within 5% dose-difference. Relative dose comparison between Eclipse dose, EBT dose and PRESAGE dose was conducted using profiles and gamma comparisons (4% dose-difference and 4 mm distance-to-agreement). Profiles showed good agreement between measurement and calculation except along steep dose gradient regions where Eclipse modelling might be inaccurate. Gamma comparisons showed that the measurement and calculation showed good agreement (>96%) if edge artefacts in measurements are ignored. In conclusion, the PRESAGE/optical-CT dosimetry system was found to be feasible as an independent dosimetry tool in the RPC IMRT H&N phantom.

Trajectory analysis and pullout strength of self-centering lumbar pedicle screws

An experiment was performed to study the limits of the ability of screws designed to center themselves in the pedicle during insertion, and to study whether straight-ahead versus inward screw insertion trajectories differ in their resistance to pullout. Forty-nine human cadaveric lumbar vertebrae were studied. Pedicle screws were inserted in trajectories starting 0 degrees, 10 degrees, 20 degrees, or 30 degrees from the optimal trajectory, either medially or laterally misdirected. The surgeon then inserted the screw with forward thrust but without resisting the screw's tendency to reorient its own trajectory during insertion. On the opposite pedicle, a control screw was inserted with the more standard inward-angled anatomical trajectory and insertion point. Cortical wall violation during insertion was recorded. Screws were then pulled out at a constant displacement rate while ultimate strength was recorded. Lateral misdirection as small as 10 degrees was likely to lead to cortical wall violation (3 of 7 violations). Conversely, medial misdirection usually resulted in safe screw insertion (1 of 21 violations for 10 degrees, 20 degrees, or 30 degrees medial misdirection). The resistance to pullout of screws inserted in a straight-ahead trajectory did not differ significantly from that of screws inserted along an inward trajectory (p = 0.68). Self-tapping, self-drilling pedicle screws can redirect themselves to a much greater extent during medial than during lateral misdirection. The cortical wall is more likely to be violated laterally than medially. The strength of straight-ahead and inward trajectories was equivalent.

The Tampon Test for Vulvodynia Treatment Outcomes Research

A standardized tampon insertion and removal test, the Tampon Test provides an alternative to sexual intercourse pain as an outcome measure for vulvodynia research. We report upon the reliability, validity, and responsiveness to change of the Tampon Test as an outcome measure for vulvodynia clinical trials. Outcome measures were assessed in women enrolled in the Vulvar Vestibulitis Clinical Trial, a randomized clinical trial of oral desipramine and topical lidocaine effectiveness. Reliability estimates of the Tampon Test using the Kappa statistic evaluated week-to-week measures at baseline. Tampon Test construct and discriminant validity were assessed through correlation with other outcome measures. Patients' ability to regularly perform the Tampon Test was compared with regularity of reporting intercourse pain. During the 2-week baseline phase, women with vulvodynia reported stable mean Tampon Test scores 4.6+/-2.6 (week -2); 4.6+/-2.7 (week -1); and 4.7+/-2.8 (week 0) with moderate week-to-week reliability (weighted Kappa 0.52). Over an 8-week phase of trial intervention, change in the Tampon Test measure significantly correlated to a number of outcome measures, including daily pain (r=0.42), intercourse pain (r=0.35), cotton swab vestibular pain (r=0.38), and the Brief Pain Inventory (r=0.49). Women with vulvodynia study participants performed the Tampon Test 96.3% of the requested time, which was twofold higher adherence than intercourse pain measurement (49.7%). The Tampon Test reflects a real life experience that is reliable, with good construct validity as shown by the breadth of correlated outcome measures. The Tampon Test is an appropriate outcome measure for vulvodynia research that can be considered for use as the primary efficacy endpoint in clinical trials of treatments for vulvodynia. ClinicalTrials.gov, www.clinicaltrials.gov, NCT00276068 II.

Comparison of Two Insertion Techniques of ProSeal™ Laryngeal Mask Airway

This study compared two insertion techniques of ProSeal laryngeal mask airway. A total of 160 female patients (American Society of Anesthesiologists physical status I or II; age 18-80 yrs) undergoing gynecologic surgery were randomly allocated to the standard or rotational technique groups. In the standard technique group (n = 80), ProSeal laryngeal mask airway insertion was performed by a single experienced user using digital manipulation. In the rotational technique group (n = 80), the ProSeal laryngeal mask airway was rotated counter clockwise through 90 degrees in the mouth and advanced until the resistance of the hypopharynx was felt, and then straightened out in the hypopharynx (n = 80). The ease of insertion was assessed by the success rate at the first attempt. Heart rate and mean blood pressure were recorded 1 min before and 1 min after insertion. Postoperative complications were noted. The success rate of insertion at the first attempt was higher for the rotational technique (100% vs. 85%, P < 0.001). The overall success rate, i.e., successful insertion within three attempts, was 94% for the standard technique versus 100% for the rotational technique. There was no significant change in heart rate, but mean blood pressure increased significantly with the standard technique (P = 0.001). The incidence of blood staining (9% vs. 36%, P < 0.001) and sore throat (8% vs. 25%, P = 0.005) was lower with the rotational technique. The rotational technique is more successful than the standard technique and is associated with less pharyngeal mucosal trauma, as evidenced by a lower incidence of sore throat and mucosal bleeding.

Method for Improving Sequence Coverage Uniformity of Targeted Genomic Intervals Amplified by LR-PCR Using Illumina GA Sequencing-by-Synthesis Technology

One approach for high-throughput population-based sequencing of targeted intervals in the human genome is to amplify the regions using long-range PCR (LR-PCR) followed by sequencing with next-generation sequencing (NGS) technologies. Utilizing this method, we have observed that the 50 bp located at the amplicon ends account for more than 50% of the sequenced bases and that the sequence coverage depth of base pairs within an amplicon is highly variable. Here we propose an explanation for the overrepresentation of the amplicon ends and show that the use of 5'-blocked primers for the LR-PCR reaction reduces their overrepresentation. Furthermore, we demonstrate that using a 600-bp library insert size rather than the standard 200-bp insert size results in more uniform sequence coverage depth. The capability to increase sequence coverage uniformity greatly improves the effective throughput of NGS platforms.