David A. Fitch

Use of the supercapsular percutaneously assisted total hip approach for femoral neck fractures: surgical technique and case series

BackgroundFemoral neck fractures are common injuries in the geriatric population associated with high morbidity and mortality rates. Studies have shown outcomes can be positively influenced by early postoperative mobilization. The supercapsular percutaneously assisted total hip (SuperPath) surgical technique has been shown to lead to early mobilization for osteoarthritic total hip replacement patients and as such has the potential to provide similar benefits in fracture patients. This manuscript provides a detailed description of this technique using hemiarthroplasty to treat femoral neck fractures and presents the first case series of this application.MethodsSeventeen patients with femoral neck fractures managed with this technique at two separate institutions were reviewed. In an attempt to minimize blood loss and enhance early mobilization, hemiarthroplasty utilizing the SuperPath technique was performed. The authors noticed decreased blood loss, operative time, and postoperative narcotic usage when compared to their previous experiences using traditional techniques.ConclusionsEarly mobilization following femoral neck fractures has been shown to decrease mortality and morbidity. There is little existing literature on the use of tissue-sparing surgical techniques for this application, and none details the use of the SuperPath technique for it. The described case reports suggest the technique is a viable option for bipolar hemiarthroplasty to treat femoral neck fractures. Appropriately designed future studies are needed to confirm findings and definitively compare outcomes to traditional approaches.

Early surgical and functional outcomes comparison of the supercapsular percutaneously-assisted total hip and traditional posterior surgical techniques for total hip arthroplasty: protocol for a randomized, controlled study

BACKGROUND Total hip arthroplasty (THA) is one of the most commonly performed and successful orthopaedic surgeries. While the long-term success of THA is well documented, there is still significant room for improving patient speed of recovery and return to activities. The surgical technique used during THA has the potential to affect these early outcomes. METHODS The described design is a single center, prospective, randomized, controlled study. Subjects will be randomized to receive THA using either the supercapsular percutaneously-assisted total hip (SuperPath) or traditional posterior surgical techniques. Subjects will be evaluated using Timed Up and Go (TUG), Timed Stair Climb (TSC), Hip Dysfunction and Osteoarthritis Outcome Score (HOOS), and Visual Analog Scale (VAS) for pain level estimation preoperatively, during the hospital stay, and at 2, 6 weeks, and 100 days post-discharge. Other endpoints to be evaluated include: length of stay (LOS); discharge status; transfusion rates; readmission rates; complication rates; operative time; date returned to work; and acetabular component anteversion and inclination angles. DISCUSSION The described study will determine the effect of a tissue-sparing surgical technique on short term subject recovery following THA in comparison to the most commonly used technique in clinical practice.

Esophageal Electric Fields are Correlated to Atrial Defibrillation Thresholds: Towards Patient-Specific Optimization of External Atrial Defibrillation

Studies have investigated the effect of defibrillator paddle position on the efficacy of external electrocardioversion of atrial fibrillation, without agreeing upon an optimal placement. We wish to investigate using esophageal electric fields (EEFs) to predict atrial defibrillation thresholds (ADFTs) on a patient-specific basis. We propose to (1) investigate the relationship between EEFs and ADFTs using computer simulations, (2) develop an esophageal probe that can accurately measure three-dimensional electric fields and (3) investigate the relationship between EEFs and ADFTs values in-vivo. Sixteen anterior-anterior and eleven anterior-posterior placements were simulated yielding a negative relationship between EEFs and ADFTs (R2=0.91 and 0.93, respectively). An esophageal probe was developed that accurately measures EEFs. Animal studies showed a negative relationship between EEFs and ADFTs. This data suggests using EEFs to predict ADFTs on a patient-specific basis is plausible

Esophageal electric fields are predictive of atrial cardioversion success-a finite element analysis.

BACKGROUND Atrial fibrillation (AF) is a debilitating cardiac arrhythmia, one potential treatment of which is external cardioversion. Studies have shown external cardioversion success is affected by electrode placement and that esophageal electric fields (EEFs) during low strength shocks have the potential to be used in determining patient-specific optimal electrode placements during animal experiments. The objective of this study was to determine the relationship between EEFs and atrial defibrillation thresholds (ADFTs) during computer simulations using an anatomically realistic computer model of a human torso. METHODS Over 600 electrode placements were simulated during which EEFs were compared to ADFTs. RESULTS There was no single optimal electrode placement with multiple electrode placements resulting in similarly low ADFTs. There was over 40% difference in the ADFTs between the most and least optimal electrode configurations. There was no correlation between EEFs and ADFTs for all electrode placements, but a strong negative correlation when small shifts from clinically relevant electrode placements were performed. CONCLUSIONS These results suggest a small shifts protocol from clinically relevant electrode placements has the potential to increase the probability of successful cardioversion on the first shock and reduce the cumulative number of shocks and energy to which patients are exposed.

An esophageal probe for measuring three-dimensional electric fields during external cardiac defibrillation

External defibrillation is a common treatment for the cardiac arrhythmia atrial fibrillation. Electrode placement has been shown to affect defibrillation efficacy and required energy levels. We suggest investigating the relationship between esophageal electric fields (EEFs) and atrial defibrillation thresholds to determine the feasibility of creating patient-specific electrode placements using EEFs. This study presents the design and implementation of an esophageal probe (EP) that accurately measures three-dimensional electric fields. The root-mean-square error of the EP was 1.69% as determined by measurements performed in an electrolytic tank. The EP also performed well during in vivo testing in a pig. There was a strong positive relationship between EEF(2)s and applied energy during defibrillation strength shocks. The EEF measurements were also repeatable, with less than 4.24% difference between repeated shocks. This is the first description of a probe designed specifically for measuring electric fields in the esophagus.