Avril D. McCarthy

Passive haptics in a knee arthroscopy simulator: is it valid for core skills training?

Previous investigation of a cost-effective virtual reality arthroscopic training system, the Sheffield Knee Arthroscopy Training System (SKATS), indicated the desirability of including haptic feedback. A formal task analysis con firmed the importance of knee positioning as a core skill for trainees learning to navigate the knee arthroscopically. The system cost and existing limb interface, which permits knee positioning, would be compromised by the addition of commercial active haptic devices available currently. The validation results obtained when passive haptic feedback (resistance provided by physical structures) is provided indicate that SKATS has construct, predictive and face va lidity for navigation and triangulation training. When tested using SKATS, experienced surgeons (n = 11) performed significantly faster, located significantly more pathologies, and showed significantly shorter arthroscope path lengths than a less experienced surgeon cohort (n = 12). After SKATS training sessions, novices (n = 3) showed significant improvements in: task completion time, shorter arthroscope path lengths, shorter probe path lengths, and fewer arthroscope tip contacts. Main improvements occurred after the first two practice sessions, indicating rapid familiarization and a training effect. Feedback from questionnaires completed by orthopaedic surgeons indicates that the system has face validity for its remit of basic arthroscopic training.

The feasibility of a mixed reality surgical training environment

The Sheffield knee arthroscopy training system (SKATS) was originally a visual-based virtual environment without haptic feedback, but has been further developed as a mixed reality-training environment through the use of tactile augmentation (or passive haptics). The design of the new system is outlined and then tested. In the first experiment described, the effect of tactile augmentation on performance is considered by comparing novice performance using the original and mixed reality system. In the second experiment the mixed reality system is assessed in terms of construct validity by comparing the performance of users with differing levels of surgical expertise. The results are discussed in terms of the validity of a mixed reality environment for training knee arthroscopy.

Beyond the visuals: tactile augmentation and sensory enhancement in an arthroscopy simulator

This paper considers tactile augmentation, the addition of a physical object within a virtual environment (VE) to provide haptic feedback. The resulting mixed reality environment is limited in terms of the ease with which changes can be made to the haptic properties of objects within it. Therefore sensory enhancements or illusions that make use of visual cues to alter the perceived hardness of a physical object allowing variation in haptic properties are considered. Experimental work demonstrates that a single physical surface can be made to ‘feel’ both softer and harder than it is in reality by the accompanying visual information presented. The strong impact visual cues have on the overall perception of object hardness, indicates haptic accuracy may not be essential for a realistic virtual experience. The experimental results are related specifically to the development of a VE for surgical training; however, the conclusions drawn are broadly applicable to the simulation of touch and the understanding of haptic perception within VEs.

Three-Dimensional Analysis of Different First Metatarsal Osteotomies in a Hallux Valgus Model

Background: This study evaluates and compares three-dimensional (3-D) changes in geometry of the first metatarsal (MT1) independent of soft tissue corrections of 5 common osteotomies: three distal (Chevron, Mitchell, and Wilson), one proximal (Stephens basal), and one combined proximal/distal (Scarf), using standardized synthetic bone models. Materials and Methods: A digitizing system was used to measure and record points on the synthetic bone models in 3-D space. Computer vector analysis calculated 3-D rotations and translations of the MT1 head plus the conventional intermetatarsal angle (IMA) and distal metatarsal articular angle (DMAA). Results: The Wilson and Mitchells osteotomies produced significant shortening (p < 0.001) in contrast to the three other osteotomies. All the osteotomies produced a reduction in the 3-D IMA. The Scarf and Stephens basal osteotomies reduced the DMAA. All of the osteotomies resulted in lateral translations and depression of the MT1 head. While there were no significant (p > 0.05) translational differences between the Scarf and Stephens basal osteotomies, there were rotational differences, with the Stephens basal producing significantly more plantar flexion (p = 0.000) and pronation (p < 0.001) than the Scarf. Conclusion: This geometric study indicated many of the MT1 head changes following metatarsal osteotomy to be out-of-plane translational and multiplanar rotations which cannot be determined using AP radiographs alone. Clinical Relevance: We advocate judicious choice of osteotomy to achieve the desired correction of hallux valgus in each individual.

Head-Up; An interdisciplinary, participatory and co-design process informing the development of a novel head and neck support for people living with progressive neck muscle weakness.

Abstract This paper presents the Head-Up project, that aims to provide innovative head support to help improve posture, relieve pain and aid communication for people living with progressive neck muscle weakness. The initial focus is motor neurone disease. The case study illustrates collaborative, interdisciplinary research and new product development underpinned by participatory design. The study was initiated by a 2-day stakeholder workshop followed by early proof-of-concept modelling and patient need evidence building. The work subsequently led to a successful NIHR i4i application funding a 24-month iterative design process, patenting, CE marking and clinical evaluation. The evaluation has informed amendments to the proposed design refered to here as the Sheffield Support Snood (SSS). The outcome positively demonstrates use and performance improvements over current neck orthoses and the process of multidisciplinary and user engagement has created a sense of ownership by MND participants, who have since acted as advocates for the product.

Assessment of the Sheffield Support Snood, an innovative cervical orthosis designed for people affected by neck muscle weakness

BACKGROUND This study aimed at quantifying the biomechanical features of the Sheffield Support Snood, a cervical orthosis specifically designed for patients with neck muscle weakness. The orthosis is designed to be adaptable to a patients level of functional limitation using adjustable removable supports, which contribute support and restrict movement only in desired anatomical planes. METHODS The snood was evaluated along with two commercially available orthoses, the Vista and Headmaster, in a series of flexion, extension, axial-rotation and lateral flexion movements. Characterization was performed with twelve healthy participants with and without the orthoses. Two inertial-magneto sensors, placed on the forehead and sternum, were used to quantify the necks range of motion. FINDINGS In its less supportive configuration, the snood was effective in limiting movements to the desired planes, preserving free movement in other planes. The Headmaster was only effective in limiting flexion. The range of motion achieved with the snood in its rigid configuration was equivalent (P>0.05, effect size<0.4) to that achieved with the Vista, both in trials performed reaching the maximum amplitude (range of motion reduction: 25%-34% vs 24%-47%) and at maximum speed (range of motion reduction: 24%-29% vs 25%-43%). INTERPRETATION The Sheffield Support Snood is effectively adaptable to different tasks and, in its most supportive configuration, offers a support comparable to the Vista, but providing a less bulky structure. The chosen method is suitable for the assessment of range of motions while wearing neck orthoses and is easily translatable in a clinical context.

Evaluating a novel cervical orthosis, the Sheffield Support Snood, in patients with amyotrophic lateral sclerosis/motor neuron disease with neck weakness

Abstract Current practice and guidelines recommend the use of neck orthoses for people with amyotrophic lateral sclerosis (ALS) to compensate for neck weakness and to provide surrogate neck control. However, available options are frequently described by patients as restrictive and unsuitable and there was a need for a new device that addressed the needs of people with ALS. This project utilized a co-design process to develop a new neck orthosis that was more flexible yet supportive. Following development of a prototype device, a mixed methods cohort study was undertaken with patients and carers, in order to evaluate the new orthosis. Twenty-six patients were recruited to the study, with 20 of these completing all phases of data collection. Participants described the impact of neck weakness on their life and limitations of existing supports. Evaluation of the new orthosis identified key beneficial features: notably, increased support while providing a greater range of movement, flexibility of use, and improved appearance and comfort. In conclusion, the results of this evaluation highlight the value of this alternative option for people with ALS, and potentially other patient groups who require a neck orthosis.

Recent developments in technology for the assessment and management of incontinence

Abstract Urinary incontinence, the leakage of urine, is a common condition, which can have a significant impact on a patient’s quality-of-life. Incontinence may arise as a consequence of a weakness of the urinary sphincter or bladder dysfunction, usually over-activity. Incontinence therapies occupy a large proportion of the healthcare budget. As no single device to manage incontinence is appropriate for all situations, a diverse range of products are available on the market and the development of improved products based on fundamental designs has been slow. This review highlights some of the key issues of continence care and describes the current technology and recent developments involved in the diagnosis, assessment and treatment of incontinence, along with the strengths and limitations of these methods. These issues are imperative to address if improved technology is to be developed.

Developing a new treatment device: How to get an idea to the marketplace†‡§¶

A good idea does not inevitably lead to successful innovation; it needs additional “drivers” and coherent activity of a specialized team. The initial idea needs proof‐of‐concept and prototype testing. Alongside, market review must anticipate future need and competitors, and ensure that no current patents are infringed. The likelihood that reimbursement will be secured and that health systems will “adopt” the device has to be considered. Intellectual property (IP) protection is needed to maintain sole rights to exploit the core concept. Non‐disclosure agreements (NDA) should be put in place, and commercial considerations should be remembered before any disclosure in the public domain, including publications. Prospective business partners will review the concept from many perspectives, including stage of device development, effective IP protection, any clinical trial evidence, and whether the device aligns with their business strategy. Royalties arising from sales of a marketed device are distributed to all parties contributing to its development; the party bearing the greater financial burden of developing the final product will gain the greater share of royalties. The innovators employer will have a call on proceeds if the idea arose in the course of employment. All stages of development require fastidious documentation to meet requirements of the regulatory authorities responsible for permitting use in patients. Specific regulatory requirements depend on which region(s) of the world the device will be marketed in. This review explains all stages of the innovation pathway from concept to adoption, giving practical advice and signposting expertise relevant to each stage. Neurourol. Urodynam. 31:429–436, 2012.

Interpretation of the scarf osteotomy by 10 surgeons.

BACKGROUND The study compared three-dimensional (3D) changes in geometry of the first metatarsal following scarf osteotomy performed on standardised Sawbone® models by consultant foot and ankle surgeons. The study considered the inter-surgeon variances in interpretation and performance of the scarf osteotomy with respect to intra-surgeon variances. METHODS The analysis used an accurate digitising system to measure and record points on the Sawbone® models in 3D space. Computer software performed vector analysis to calculate 3D rotations and translations of the first metatarsal head as well as the inter-metatarsal angle. Bone cut lengths and displacements were measured using a digital Vernier caliper. One surgeon performed the osteotomy 10 times to form an intra-surgeon control dataset, while 10 different surgeons each did one scarf osteotomy to form an inter-surgeon test dataset. RESULTS Both surgical groups produced reductions in the 3D inter-metatarsal angle with non-significant differences between the groups (p>0.05). In contrast, the test group demonstrated highly significant (p=0.000) greater variance compared with the control dataset for all of the variables associated with surgical technique. In addition, there were highly significant (p=0.02 and 0.002) greater variances in the interpretation of the degree to which the metatarsal head should be translated medially (X) and inferiorly (Z). There was also a significant (p=0.001) increase in variances in the rotations about the dorsi/plantar-flexion (X) axis. The only significant differences (all p=0.000) attributable solely to differences in mean values were in proximal-distal (Y) translation, pronation (Y) rotation and medial (Z) rotation. The test group applied greater medial and plantar-flexion rotation of the metatarsal head than the control surgeon and significantly less (p=0.000) shortening of the first metatarsal than the control surgeon. CONCLUSIONS The results of this geometric study demonstrate the versatility of the scarf osteotomy. As a result of the multi-planar nature of the osteotomy, there is a potential risk of producing unintended rotational mal-unions in all three planes. These rotational mal-unions may account for some of the poorer outcomes documented within the literature.