Placement Of Instrumentation Research Articles

O-arm failure traps patient prone on a Jackson table

The O-arm Surgical Imaging System (Medtronic Sofamor Danek, Memphis, TN, USA) is an increasingly popular tool for spinal surgical procedures that allows for intraoperative acquisition of multi-dimensional spinal imaging that can be used either to confirm placement of spinal instrumentation or to guide spinal screw placement in conjunction with a navigation system. The machine is typically placed open from the side of the patient positioned prone on the Jackson spinal table (Mizuho OSI, Union City, CA, USA) and then closed to complete a ring around the patient to acquire images. A failure of the O-arm opening mechanism can lead to a patient becoming effectively trapped within the device with limited physician access to the patient’s body, a situation that may be remedied by using a manual opening procedure. This report highlights a patient safety issue encountered when a mechanical failure of the O-arm occurred and one of the two tools required for its manual opening was missing. We describe the improvised method employed to successfully open the device.

Liver function testing on the Abaxis Piccolo Xpress: Use in Ebola virus disease protocols

BackgroundLaboratories that choose a point‐of‐care approach for liver function testing in patients undergoing evaluation for Ebola virus disease (EVD) have few options to choose from. The primary objective of this study was to conduct a performance characterization of a Clinical Laboratory Improvement Amendments (CLIA)-waived liver function panel on the Abaxis Piccolo® Xpress chemistry analyzer. The secondary objectives were to evaluate multiple specimen types, characterize whole blood specimen stability, and validate disposable exact transfer pipettes. Our final objective was to assess instrument airflow from a biosafety perspective. MethodsAn instrument performance characterization, including precision, linearity, accuracy, reference interval verification, and specimen type evaluation was conducted using Liver Panel Plus reagent discs on the Piccolo® Xpress. ResultsAll assays demonstrated acceptable linearity (slopes, 0.938–1.061; observed error, 0.8–6.3%). Assay precision was 0.0–3.6% (%CV; within-day studies) and 0.9–5.6% (between-day studies). Method comparison experiments (versus Roche cobas c502/c702 chemistry analyzers) showed excellent correlation for most assays, although a few notable differences were observed (Piccolo versus Roche): alkaline phosphatase, −18.6%; amylase, −29.0%; total bilirubin, +0.3mg/dl. Pre-programmed reference intervals were verified except for the alkaline phosphatase (male and female) and alanine aminotransferase (female), which had greater than 10% of results fall below the programmed ranges. Piccolo instrument results were largely consistent across specimen types tested (lithium-heparin whole blood, lithium-heparin plasma, and serum), although some statistical differences were observed for aspartate aminotransferase, gamma glutamyltransferase, and total protein. Whole blood time course studies demonstrated that some analytes (albumin, amylase, and total protein) showed remarkable stability, while others (such as aspartate aminotransferase) showed a slight trend toward decreased activity over time. Exact volume transfer pipettes provided an effective disposable option for disc loading. Finally, airflow studies suggested that, in the context of EVD protocols, instrument placement in a biosafety level (BSL) 2 cabinet or greater is justified. ConclusionsGiven its analytical performance and ease of operation, the Piccolo Xpress was transferred to a BSL-2 cabinet in our BSL-3 suite for use in our hospital's diagnostic protocol for providing liver function testing in patients undergoing evaluation for EVD.

Unplanned reoperation after lumbopelvic fixation with S-2 alar-iliac screws or iliac bolts.

S-2 alar-iliac (S2AI) screws are an attractive alternative to conventional fixation with iliac bolts because they are lower profile, require less muscle dissection, and have greater pullout strength. Few studies, however, compare outcomes between these techniques. The authors conducted a retrospective cohort study of consecutive adult patients at a single institution from December 2009 to March 2012 who underwent lumbopelvic fixation using S2AI screws or iliac bolts. Medical records were reviewed for patients with clinical failure, defined as an unplanned reoperation because of instrumentation failure and/or wound-related complications. Univariate, multivariate, and survival analyses were used to compare patients who required reoperation with those who did not. Method of pelvic fixation was the main predictor variable of interest, and the authors adjusted for potential confounding risk factors. Of the 60 patients included, 23 received S2AI screws. Seventeen patients (28%) underwent an osteotomy. The mean follow-up was 22 months. A Kaplan-Meier survival model was used to evaluate the time to reoperation from the initial placement of lumbopelvic instrumentation. The failure-free rate was 96.6% at 6 months, 87.0% at 1 year, and 73.5% at 2 years. Reoperation was more common in patients with iliac bolts than in those with S2AI screws (13 vs 2; p = 0.031). Univariate analysis identified potential risk factors for unplanned reoperation, including use of iliac bolts (p = 0.031), absence of L5-S1 interbody graft (p = 0.048), previous lumbar fusion (p = 0.034), and pathology other than degenerative disease or scoliosis (p = 0.034). After adjusting for other risk factors, multivariate analysis revealed that the use of S2AI screws (OR 8.1 [1.5-73.5]; p = 0.030) was the only independent predictor for preventing unplanned reoperation. Both S2AI screws and iliac bolts were effective at improving fusion rates at the lumbosacral junction. The use of S2AI screws, however, was independently associated with fewer unplanned reoperations for wound-related complications and instrumentation failures than the use of iliac bolts.

A method for predicting the performance of a steelband orchestra in arbitrary environments

One of the challenges in steelpan performance is in determining the best placement of the various instruments in an orchestra so as to achieve the level performance desired by the musical arranger. This research attempts to develop a method for analyzing the performance of the tenor steelpan in arbitrary acoustic spaces using the room acoustic modeling software, Enhanced Acoustic Simulation for Engineers (EASE). When provided with an acoustic characterization of a speaker system, particularly the magnitude and phase radiation data, and the room in which it is located, EASE can be used to predict the resulting acoustic sound-field. EASE also requires an electrical equivalent of the instrument's sound source and, through its auralization feature, allow the user to actually hear an actual performance. EASE uses a variety of reconstruction techniques, such as ray tracing and boundary element method, to provide the most accurate responses. The study will verify the approach by comparing simulation results on direct sound coverage, total SPL, Clarity (C80), Centre Time, Reverberation, and Early decay times of the instrument with real time measurements in the usual 1/3-band octave frequency resolution. Although the work focuses on the tenor steelpan, it can be easily extended to predict the performance of an entire ensemble of steelpans in any given space.

Unilateral fixation for treatment of occipitocervical instability in children with congenital vertebral anomalies of the craniocervical junction.

OBJECT Patients with occipitocervical (OC) instability from congenital vertebral anomalies (CVAs) of the craniocervical junction (CCJ) often have bony abnormalities that make instrumentation placement difficult. Within this patient population, some bilateral instrumentation constructs either fail or are not feasible, and a unilateral construct must be used. The authors describe the surgical management and outcomes of this disorder in patients in whom unilateral fixation constructs were used to treat OC instability. METHODS From a database of OC fusion procedures, the authors identified patients who underwent unilateral fixation for the management of OC instability. Patient characteristics, surgical details, and radiographic outcomes were reviewed. In each patient, CT scans were performed at least 4 months after surgery to evaluate for fusion. RESULTS Eight patients with CVAs of the CCJ underwent unilateral fixation for the treatment of OC instability. For 4 patients, the procedure occurred after a bilateral OC construct failed or infection forced hardware removal. For the remainder, it was the primary procedure. Two patients required reoperation for hardware revision and 1 developed nonunion requiring revision of the bone graft. Ultimately, 7 patients demonstrated osseous fusion on CT scans and 1 had a stable fibrous union. CONCLUSIONS These findings demonstrate that a unilateral OC fixation is effective for the treatment of OC instability in children with CVAs of the CCJ in whom bilateral screw placement fails or is not feasible.

Incision Length in Small Incision Total Knee Arthroplasty: How Long of an Incision Is Needed?

This prospective review studied incision length with a small incision TKA technique and compared measured incision lengths to various anatomic and clinical parameters. We prospectively reviewed 357 cases of primary total knee arthroplasty using a small paramedial incision and utilizing small incision instrumentation. By using linear regression analysis, we found that incision length was generally related to the width of the distal cut femur and the width of the proximal cut tibia. Incision length was not related to height, weight, BMI, or femoral implant width. Clinically based upon our data, a reasonable starting incision for small incision TKA (as measured in knee extension) is a length that is 1.6 times the measured width of the distal femur. The surgeon should always extend the incision if he/she encounters difficulty in exposure and/or placement of instrumentation.

Image-Guided Spinal Navigation for C1-C2 Instrumentation: Part I.

Disorders of the spine are one of the oldest known human maladies, with descriptions found in ancient medical literature. As in many other areas of medicine, treatment of patients with these disorders has undergone rapid progress over the last century. Among treatment modalities, spinal instrumentation has been a significant technical advancement. Increased use of spinal instrumentation has spurred the need for accurate positioning of screws/instrumentation and enhanced stability of the construct. Traditionally, these have been placed using anatomic landmarks and intraoperative fluoroscopy. In patients with advanced degenerative disease or trauma, or in those with severe curvature deformity, anatomy can be of limited help. With intraoperative fluoroscopy, limited visualization can be a significant issue, especially in patients with a large body habitus. Image guidance, by providing live, accurate information for placement of instrumentation, significantly improves upon these issues. Image guidance has been used in neurologic surgery during recent decades. It was employed initially for intracranial applications, including treatment of brain disorders, with significant benefits and is now used routinely as an important adjunct tool in the operating room for intracranial neurologic surgery. Only more recently has image guidance been used in spine surgery.

Substantial clinical benefit of minimally invasive lateral interbody fusion for degenerative spondylolisthesis.

Conventional lumbar arthrodesis for the treatment of degenerative spondylolisthesis (DS) is associated with high complication rates and variable clinical efficacy. Modern minimally invasive (MIS) approaches may reduce the morbidity and produce greater clinical improvement compared to traditional surgical techniques. The objective of this study is to report radiographic outcomes and evaluate clinical improvements in the context of substantial clinical benefit for DS patients treated with a MIS 90° lateral, transpsoas approach for lumbar interbody fusion. From 2005 to 2011, 60 consecutive patients were treated with MIS lateral interbody fusion for Grade I or II DS at a single institution. Mean patient age was 68 years, 75 % were female, and 30 % had undergone previous lumbar surgery. A total of 71 levels were treated, supplemental posterior fixation was used in 57 (95 %) cases, and 26 (43 %) patients underwent additional direct posterior decompression. Average follow-up was 20.3 months. Average ORT, EBL, and LOS were 206 min, 83 cc, and 1.29 days, respectively. Complications occurred in 3 (5 %) patients. Transient approach-related thigh/groin pain was observed in 5 (8 %) cases. There were no cases of pseudoarthrosis. At 1 year, LBP improved 71 %, LP improved 68 %, ODI decreased 52 %, and SF-36 PCS and MCS improved 43 and 21 %, respectively. Substantial clinical benefit was met by 94.7 % of patients on NRS LBP, by 84.6 % on NRS LP, by 83.7 % on ODI, and by 66.7 % on SF-36 PCS. Disc height increased 71 % and segmental lordosis increased 27.8 % at treated levels. Foraminal height, width, and volume increased 19.7, 18.0, and 39.6 %, respectively. Slip improved 60.7 % with interbody fusion only and further improved to 69.2 % after the placement of supplemental instrumentation. MIS lateral interbody fusion in the treatment of DS resulted in significant improvements in clinical and radiographic outcomes, with a low complication rate and a high proportion of patients achieving substantial clinical benefit.

Sensor positioning and experimental constraints influence estimates of local dynamic stability during repetitive spine movements

Application of non-linear dynamics analyses to study human movement has increased recently, which necessitates an understanding of how dependent measures may be influenced by experimental design and setup. Quantifying local dynamic stability for a multi-articulated structure such as the spine presents the possibility for estimates to be influenced by positioning of kinematic sensors used to measure spine angular kinematics. Oftentimes researchers will also choose to constrain the spine׳s movement by physically restraining the pelvis and/or using targets to control movement endpoints. Ten healthy participants were recruited, and asked to perform separate trials of 35 consecutive cycles of spine flexion under both constrained and unconstrained conditions. Electromagnetic sensors that measure three-dimensional angular orientations were positioned over the pelvis and the spinous processes of L3, L1, and T11. Using the pelvic sensor as a reference, each sensor location on the spine was used to obtain a different representation of the three-dimensional spine angular kinematics. Local dynamic stability of each kinematic time-series was determined by calculating the maximum finite-time Lyapunov exponent (λmax). Estimates for λmax were significantly lower (i.e. dynamically more stable) for spine kinematic data obtained from the L3 sensor than those obtained from kinematic data using either the L1 or T11 sensors. Likewise, λmax was lower when the movement was constrained. These results emphasize the importance of proper placement of instrumentation for quantifying local dynamic stability of spine kinematics and are especially relevant for repeated measures designs where data are obtained from the same individual on multiple days.

Protection of a Nuclear Reactor Monitoring System against Gross Measurement Errors

Data Validation and Reconciliation (DVR) is a basic tool for protection of industrial monitoring systems against gross measurement errors. However, the power of this approach is frequently not fully exploited. This paper concentrates on protection of key results against gross and systematic errors. On‐line monitoring can allow a continuous protection of measurement targets against gross errors in measurement chains. The measurement target can be, for example, a nuclear reactor heat output while errors can be hidden in measured flows and state variables of steam and water. The methodology presented here allows a gross error to be identified while maintaining an accurate value of the target variable. In analogy with statistics (power of statistical tests) we can define the probability of success as a power of the Monitoring System Self‐Protection (MSSP). A new simple method for assessing the MSSP power is presented. The MSSP is important for monitoring system maintenance and the optimal placement of additional instruments. It shows which primary variables are self‐checked by the redundancy of the system and which should be checked (calibrated) independently. The problem is illustrated by an example taken from one nuclear power station.

Placement of C1 Pedicle Screws Using Minimal Exposure: Radiographic, Clinical, and Literature Validation.

Traditional C1-2 fixation involves placement of C1 lateral mass screws. Evolving techniques have led to the placement of C1 pedicle screws to avoid exposure of the C1-C2 joint capsule. Our minimal dissection technique utilizes anatomical landmarks with isolated exposure of C2 and the inferior posterior arch of C1. We evaluate this procedure clinically and radiographically through a technical report. Consecutive cases of cranial-vertebral junction surgery were reviewed for one fellowship trained spinal surgeon from 2008-2014. Information regarding sex, age, indication for surgery, private or public hospital, intra-operative complications, post-operative neurological deterioration, death, and failure of fusion was extracted. Measurement of pre-operative axial and sagittal CT scans were performed for C1 pedicle width and C1 posterior arch height respectively. 64 patients underwent posterior cranio-vertebral junction fixation surgery. 40 of these patients underwent occipital-cervical fusion procedures. 7/9 (77.8%) C1 instrumentation cases were from trauma with the remaining two (22.2%) from oncologic lesions. The average blood loss among isolated C1-C2 fixation was 160cc. 1/9 patients (11.1%) suffered pedicle breech requiring sub-laminar wiring at the C1 level. On radiographic measurement, the average height of the C1 posterior arch was noted at 4.3mm (range 3.8mm to 5.7mm). The average width of the C1 pedicle measured at 5.3mm (range 2.8 to 8.7mm). The patient with C1 pedicle screw failure had a pedicle width of 2.78mm on pre-operative axial CT imaging. Our study directly adds to the literature with level four evidence supporting a minimal dissection of C1 arch in the placement of C1 pedicle screws with both radiographic and clinical validation. Justification of this technique avoids C2 nerve root manipulation or sacrifice, reduces bleeding associated with the venous plexus, and leaves the third segment of the vertebral artery unexplored. Pre-operative review of imaging is critical in the placement of C1-C2 instrumentation.

Radiologic Presentation of a Type 1 Dens Fracture

A 22-year-old man with no significant medical history presented with multiple life-threatening injuries due to a high-speed motor vehicle accident. He was neurologically intact. Admission computed tomography (CT) of the spine illustrated an oblique avulsion of the tip of the odontoid process with slight superior displacement of the proximal fragment, consistent with a type 1 dens (ie, odontoid) fracture (Figures 1-3). Additional imaging displayed a small epidural hematoma posterior to the fracture and ligamentum flavum discontinuity at the C1-C2 level, overall indicative of the acuity of the type 1 dens fracture (Figures 4,5). The injury resulted in instability of the atlanto-occipital articulation predominantly involving the lateral mass articulations with the occipital condyles, requiring placement of a halo and occipital cervical fusion and instrumentation (Figure 6). Anderson and D’Alonzo described 3 types of dens fractures with type 1 being the rarest, defined as an

Instrument placement is sub‐optimal in three of ten attempted operative vaginal deliveries

Instrument placement is sub‐optimal in three of ten attempted operative vaginal deliveries

A Novel and Reproducible Anterior Portal for Arthroscopic Distal Clavicle Excision

Acromioclavicular (AC) joint pathology is a common cause of shoulder pain, and arthroscopic distal clavicle resection is a frequently performed procedure for this problem. Here we describe a portal that is directly in line with the AC joint such that the surgeon can easily access the posterosuperior distal clavicle, as this is the region that is most frequently neglected or incompletely resected region with a “standard” or uncontrolled portal. This research provides an anatomic description for creating this anterior portal that preserves local anatomy and is both safe and effective for glenohumeral and AC joint access using reproducible anatomic landmarks. The technique was validated using cadaveric dissection and yields a method of establishing the anterior portal for distal clavicle excision with a safe corridor for placement of instruments in a reliable manner that does not disrupt the important stabilizers of the glenohumeral or AC joints. Level of Evidence: Level IV.

Risk factors and morbidity associated with suboptimal instrument placement at instrumental delivery: observational study nested within the Instrumental Delivery & Ultrasound randomised controlled trial ISRCTN 72230496.

To identify risk factors and morbidity associated with suboptimal instrument placement at instrumental delivery. Observational study, nested within a randomised controlled trial. Two university-affiliated maternity hospitals. A cohort of 478 nulliparous women at term (≥37 weeks of gestation) undergoing instrumental delivery. Univariable and multivariable logistic regression analyses were performed. Risk factors for suboptimal application of vacuum or forceps, maternal and neonatal morbidity, and the sequential use of instruments, second operator, and caesarean section following failed instrumental delivery. Instrument placement was suboptimal in 138 of 478 (28.8%) deliveries. Factors associated with suboptimal instrument placement included fetal malposition (OR 2.44, 95% CI 1.62-3.66), mid-cavity station (OR 1.68, 95% CI 1.02-2.78), and forceps as the primary instrument (OR 2.01, 95% CI 1.33-3.04). Compared with optimal instrument placement, suboptimal placement was associated with prolonged hospital stay (adjusted OR 2.28, 95% CI 1.30-4.02) and neonatal trauma (adjusted OR 4.25, 95% CI 1.85-9.72). Suboptimal placement was associated with a greater use of sequential instruments (adjusted OR 3.99, 95% CI 1.94-8.23) and caesarean section for failed instrumental delivery (adjusted OR 3.81, 95% CI 1.10-13.16). The mean decision to delivery interval (DDI) was 4 minutes longer in the suboptimal group (95% CI 2.1-5.9 minutes). Suboptimal instrument placement is associated with increased maternal and neonatal morbidity and procedural complications. Greater attention should be focused on instrument placement when training obstetricians for instrumental delivery.

The Process of Discovery: Interpreting Child of Tree

The Process of Discovery: Interpreting Child of Tree is a lecture delivered at the Percussive Arts Society International Convention in Austin, Texas, in 2012. John Cage composed Child of Tree for percussion solo in 1975 and the published score is made up of hand-written instructions on how to create the form and placement of instruments needed for a performance. It is (intentionally) difficult to read. The lecture describes the history of how, in the late 1980s through early 1990s, the author constructed a performance score of the piece. This includes correspondence with John Cage that sheds light on some of the problems involved.

Application of microautologous fat transplantation in the correction of sunken upper eyelid.

Although fat grafting has been clinically applied by surgeons in esthetic and reconstructive surgery, it has widely evolved in processes such as harvesting, processing, and placement of fat, using the fat-grafting procedure, which dates back over 100 years. Surgeons frequently use fat grafting to recontour, augment, or fill soft-tissue defects, facial wrinkles, or skin problems such as depressions or scars. However, fat grafting has not been thoroughly understood and has not been conclusively standardized to ensure superior clinical results. This study was intended to determine the role of microautologous fat transplantation (MAFT) under evidence-based medicine, particularly in accurate delivery of small fat parcels. The research method involved the conceptualization of MAFT and the development of an innovative surgical instrument for fat placement. Clinically, 168 patients with sunken upper eyelids with multiple folds underwent this procedure. The major findings suggested that MAFT exhibits promising clinical results and offers a superior guideline for fat placement. Details of the technique and theoretical implications are also discussed. The therapeutic effects of MAFT and the long-term clinical results of patients with sunken upper eyelids with multiple folds indicated satisfactory outcomes. Based on the results, MAFT offers an alternative option to surgeons for performing fat grafting and provides a more favorable option for the benefit and welfare of patients by reducing the potential complications.

Staged Placement of Growing Rods for Metabolic Bone Disease and Insufficient Bone Quality: A Report of Two Cases.

We present two cases of successful staged placement of standard growing-rod instrumentation for early-onset scoliosis in children with metabolic bone disease and poor bone quality. Because use of growing-rod surgery is increasing throughout the world, we propose that a staged approach to placement of growing rods is a practical and safe option for surgeons who encounter patients with early-onset scoliosis and concomitant poor bone quality.

Spinal Instrumentation in the Setting of Primary Infection

o instrument or not to instrument is a common question in spine surgery but especially in the setting of primary T infection (i.e., osteomyelitis, discitis, or epidural abscess). In such situations, there may be fear that placing instrumentation into an incompletely treated infected area may promote bacterial seeding of the foreign body and recurrent infection. Some schools of thought advocate for an initial debridement followed by a staged placement of instrumentation, if necessary.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: electrophysiological monitoring and lumbar fusion.

Intraoperative monitoring (IOM) is commonly used during lumbar fusion surgery for the prevention of nerve root injury. Justification for its use stems from the belief that IOM can prevent nerve root injury during the placement of pedicle screws. A thorough literature review was conducted to determine if the use of IOM could prevent nerve root injury during the placement of instrumentation in lumbar or lumbosacral fusion. There is no evidence to date that IOM can prevent injury to the nerve roots. There is limited evidence that a threshold below 5 mA from direct stimulation of the screw can indicate a medial pedicle breach by the screw. Unfortunately, once a nerve root injury has taken place, changing the direction of the screw does not alter the outcome. The recommendations formulated in the original guideline effort are neither supported nor refuted with the evidence obtained with the current studies.