The majority of the population will have low back pain in their lifetime. Low back pain correlate... more The majority of the population will have low back pain in their lifetime. Low back pain correlates to degenerative pain disease (DDD) which has been linked to exposure to mechanical loads. Certain occupations involving heavy lifting also correlate with DDD. Analytical models of the spine provide estimates of loading in the spine. However, data is lacking explicitly measuring mechanical forces in the spine. This data is necessary to truly characterize the translation from overload to onset of DDD. There is a need for an implantable device that is better able to characterize the in vivo mechanical environment present in the spine.
The diagnosis of fracture nonunion following plate osteosynthesis is subjective and frequently am... more The diagnosis of fracture nonunion following plate osteosynthesis is subjective and frequently ambiguous. Initially following osteosynthesis, loads applied to the bone are primarily transmitted through the plate. However, as callus stiffness increases, the callus is able to bear load proportional to its stiffness while forces through the plate decrease. The purpose of this study was to use a “smart” fracture plate to distinguish between phases of fracture healing by measuring forces transmitted through the plate. A wireless force sensor and small adapter were placed on the outside of a distal femoral locking plate. The adapter converts the slight bending of the plate under axial load into a transverse force which is measurable by the sensor. An osteotomy was created and then plated in the distal femur of biomechanical Sawbones. Specimens were loaded to simulate single‐leg stance first with the osteotomy defect empty (acute healing), then sequentially filled with silicone (early call...
ABSTRACT Low back pain is one of the leading causes of missed work. Surgical intervention is an o... more ABSTRACT Low back pain is one of the leading causes of missed work. Surgical intervention is an option to those who have failed conservative therapy. The current gold standard of surgical procedures is bony fusion. Long term follow up of fusion patients has identified adjacent level disease as a complication. New motion preserving technologies aim to eliminate harmful effects on adjacent levels but have not been confirmed with long term clinical trials. In vitro testing provides repeatability for relative comparison between treatments, but the clinical relevance remains questionable without in vivo loads and motions. We have developed a novel in vivo/in vitro method using active motion to characterize the motion of the thoracolumbar spine using a robotic simulator. Preliminary results indicate a reduction in motion at the operative and super-adjacent level while motion is increased at all other levels. This may be compensation for the reduced motions at the operative and adjacent level.
Spinal arthrodesis is a surgical procedure used to treat painful conditions stemming from spinal ... more Spinal arthrodesis is a surgical procedure used to treat painful conditions stemming from spinal instability. Despite its widespread use, the healing time after surgery can take months. The mechanical properties of the implants used in this surgery have never been optimized. Presented is preliminary work used to quantify the relationship between the stiffness of spinal instrumentation and its effect on spinal kinematics.
Implementing implantable sensors which are robust enough to maintain long term functionality insi... more Implementing implantable sensors which are robust enough to maintain long term functionality inside the body remains a significant challenge. The ideal implantable sensing system is one which is simple and robust; free from batteries, telemetry, and complex electronics. We have developed an elementary implantable sensor for orthopaedic smart implants. The sensor requires no telemetry and no batteries to communicate wirelessly. It has no on-board signal conditioning electronics. The sensor itself has no electrical connections and thus does not require a hermetic package. The sensor is an elementary L-C resonator which can function as a simple force transducer by using a solid dielectric material of known stiffness between two parallel Archimedean coils. The operating characteristics of the sensors are predicted using a simplified, lumped circuit model. We have demonstrated sensor functionality both in air and in saline. Our preliminary data indicate that the sensor can be reasonably ...
International Journal of Sports Science & Coaching, 2017
There is a high incidence of injury during rugby tackling. Tackle biomechanics are linked to this... more There is a high incidence of injury during rugby tackling. Tackle biomechanics are linked to this injury risk. The effectiveness of educational methods in teaching safe rugby tackling for players of various ages and experience levels has not been elucidated. We hypothesized that watching an educational video on rugby tackling technique would alter lower extremity kinematics and reduce cervical spine and head acceleration during tackling. Kinematics and kinetics of 50 collegiate and high school-aged rugby players were recorded while tackling an opponent in a laboratory setting. Movement of the lower extremity, upper body, and head were quantified with a motion analysis system. Participants were shown video instruction on tackling technique then performed another series of tackles. Data were compared pre- and post-educational intervention. A fixed effects model was used to compare the effect of repetition versus educational intervention. Skilled collegiate players tackled with signifi...
BACKGROUND CONTEXT: It is estimated that up to 80% of the general population will experience at l... more BACKGROUND CONTEXT: It is estimated that up to 80% of the general population will experience at least one significant bout of low back pain in their lifetime. The leading known cause of low back pain is degenerative disc disease (DDD). Many established risk factors for low back pain and DDD are mechanical in nature and are often related to occupational activities, such as poor posture and frequent/heavy lifting. Altered mechanical loading in the spine has been shown to be a potential stimulus for disc degeneration. However, a link between occupational/environmental factors and intervertebral loading has never been demonstrated in vivo. We hypothesize that intervertebral loading is highly dependent on muscle activation and recruitment. These relationships are significant because they provide a potential connection between everyday activities and low back pain. PURPOSE: The purpose of this study was to use a novel force-sensing interbody implant to measure in vivo loads in the disc sp...
BACKGROUND Determining when athletes are able to return to sport after sports-related concussion ... more BACKGROUND Determining when athletes are able to return to sport after sports-related concussion (SRC) can be difficult. HYPOTHESIS A multimodal algorithm using cognitive testing, postural stability, and clinical assessment can predict return to sports after SRC. STUDY DESIGN Prospective cohort. LEVEL OF EVIDENCE Level 2b. METHODS Athletes were evaluated within 2 to 3 weeks of SRC. Clinical assessment, Immediate Post Concussion and Cognitive Testing (ImPACT), and postural stability (Equilibrate) were conducted. Resulting data and machine learning techniques were used to optimize an algorithm discriminating between patients ready to return to sports versus those who are not yet recovered. A Fisher discriminant analysis with leave-one-out cross-validation assessed every combination of 2 to 5 factors to optimize the algorithm with lowest combination of type I and type II errors. RESULTS A total of 193 athletes returned to contact sports after SRC at a mean 84.6 days (±88.8). Twelve sub...
Identifying the relationship between N, N'-methylenebisacrylamide (mBAAm) and swelling in acr... more Identifying the relationship between N, N'-methylenebisacrylamide (mBAAm) and swelling in acrylamide hydrogels will permit their integration with passive sensors. The incorporation of antigen and antibodies within the hydrogels will create an antigen sensitive sensor capable of detecting periprosthetic infection. The relationship between swelling and amount of mBAAm has a nonlinear relationship. Both the swelling and compliance of the hydrogel decrease with increasing amount of mBAAm.
The majority of the population will have low back pain in their lifetime. Low back pain correlate... more The majority of the population will have low back pain in their lifetime. Low back pain correlates to degenerative pain disease (DDD) which has been linked to exposure to mechanical loads. Certain occupations involving heavy lifting also correlate with DDD. Analytical models of the spine provide estimates of loading in the spine. However, data is lacking explicitly measuring mechanical forces in the spine. This data is necessary to truly characterize the translation from overload to onset of DDD. There is a need for an implantable device that is better able to characterize the in vivo mechanical environment present in the spine.
The diagnosis of fracture nonunion following plate osteosynthesis is subjective and frequently am... more The diagnosis of fracture nonunion following plate osteosynthesis is subjective and frequently ambiguous. Initially following osteosynthesis, loads applied to the bone are primarily transmitted through the plate. However, as callus stiffness increases, the callus is able to bear load proportional to its stiffness while forces through the plate decrease. The purpose of this study was to use a “smart” fracture plate to distinguish between phases of fracture healing by measuring forces transmitted through the plate. A wireless force sensor and small adapter were placed on the outside of a distal femoral locking plate. The adapter converts the slight bending of the plate under axial load into a transverse force which is measurable by the sensor. An osteotomy was created and then plated in the distal femur of biomechanical Sawbones. Specimens were loaded to simulate single‐leg stance first with the osteotomy defect empty (acute healing), then sequentially filled with silicone (early call...
ABSTRACT Low back pain is one of the leading causes of missed work. Surgical intervention is an o... more ABSTRACT Low back pain is one of the leading causes of missed work. Surgical intervention is an option to those who have failed conservative therapy. The current gold standard of surgical procedures is bony fusion. Long term follow up of fusion patients has identified adjacent level disease as a complication. New motion preserving technologies aim to eliminate harmful effects on adjacent levels but have not been confirmed with long term clinical trials. In vitro testing provides repeatability for relative comparison between treatments, but the clinical relevance remains questionable without in vivo loads and motions. We have developed a novel in vivo/in vitro method using active motion to characterize the motion of the thoracolumbar spine using a robotic simulator. Preliminary results indicate a reduction in motion at the operative and super-adjacent level while motion is increased at all other levels. This may be compensation for the reduced motions at the operative and adjacent level.
Spinal arthrodesis is a surgical procedure used to treat painful conditions stemming from spinal ... more Spinal arthrodesis is a surgical procedure used to treat painful conditions stemming from spinal instability. Despite its widespread use, the healing time after surgery can take months. The mechanical properties of the implants used in this surgery have never been optimized. Presented is preliminary work used to quantify the relationship between the stiffness of spinal instrumentation and its effect on spinal kinematics.
Implementing implantable sensors which are robust enough to maintain long term functionality insi... more Implementing implantable sensors which are robust enough to maintain long term functionality inside the body remains a significant challenge. The ideal implantable sensing system is one which is simple and robust; free from batteries, telemetry, and complex electronics. We have developed an elementary implantable sensor for orthopaedic smart implants. The sensor requires no telemetry and no batteries to communicate wirelessly. It has no on-board signal conditioning electronics. The sensor itself has no electrical connections and thus does not require a hermetic package. The sensor is an elementary L-C resonator which can function as a simple force transducer by using a solid dielectric material of known stiffness between two parallel Archimedean coils. The operating characteristics of the sensors are predicted using a simplified, lumped circuit model. We have demonstrated sensor functionality both in air and in saline. Our preliminary data indicate that the sensor can be reasonably ...
International Journal of Sports Science & Coaching, 2017
There is a high incidence of injury during rugby tackling. Tackle biomechanics are linked to this... more There is a high incidence of injury during rugby tackling. Tackle biomechanics are linked to this injury risk. The effectiveness of educational methods in teaching safe rugby tackling for players of various ages and experience levels has not been elucidated. We hypothesized that watching an educational video on rugby tackling technique would alter lower extremity kinematics and reduce cervical spine and head acceleration during tackling. Kinematics and kinetics of 50 collegiate and high school-aged rugby players were recorded while tackling an opponent in a laboratory setting. Movement of the lower extremity, upper body, and head were quantified with a motion analysis system. Participants were shown video instruction on tackling technique then performed another series of tackles. Data were compared pre- and post-educational intervention. A fixed effects model was used to compare the effect of repetition versus educational intervention. Skilled collegiate players tackled with signifi...
BACKGROUND CONTEXT: It is estimated that up to 80% of the general population will experience at l... more BACKGROUND CONTEXT: It is estimated that up to 80% of the general population will experience at least one significant bout of low back pain in their lifetime. The leading known cause of low back pain is degenerative disc disease (DDD). Many established risk factors for low back pain and DDD are mechanical in nature and are often related to occupational activities, such as poor posture and frequent/heavy lifting. Altered mechanical loading in the spine has been shown to be a potential stimulus for disc degeneration. However, a link between occupational/environmental factors and intervertebral loading has never been demonstrated in vivo. We hypothesize that intervertebral loading is highly dependent on muscle activation and recruitment. These relationships are significant because they provide a potential connection between everyday activities and low back pain. PURPOSE: The purpose of this study was to use a novel force-sensing interbody implant to measure in vivo loads in the disc sp...
BACKGROUND Determining when athletes are able to return to sport after sports-related concussion ... more BACKGROUND Determining when athletes are able to return to sport after sports-related concussion (SRC) can be difficult. HYPOTHESIS A multimodal algorithm using cognitive testing, postural stability, and clinical assessment can predict return to sports after SRC. STUDY DESIGN Prospective cohort. LEVEL OF EVIDENCE Level 2b. METHODS Athletes were evaluated within 2 to 3 weeks of SRC. Clinical assessment, Immediate Post Concussion and Cognitive Testing (ImPACT), and postural stability (Equilibrate) were conducted. Resulting data and machine learning techniques were used to optimize an algorithm discriminating between patients ready to return to sports versus those who are not yet recovered. A Fisher discriminant analysis with leave-one-out cross-validation assessed every combination of 2 to 5 factors to optimize the algorithm with lowest combination of type I and type II errors. RESULTS A total of 193 athletes returned to contact sports after SRC at a mean 84.6 days (±88.8). Twelve sub...
Identifying the relationship between N, N'-methylenebisacrylamide (mBAAm) and swelling in acr... more Identifying the relationship between N, N'-methylenebisacrylamide (mBAAm) and swelling in acrylamide hydrogels will permit their integration with passive sensors. The incorporation of antigen and antibodies within the hydrogels will create an antigen sensitive sensor capable of detecting periprosthetic infection. The relationship between swelling and amount of mBAAm has a nonlinear relationship. Both the swelling and compliance of the hydrogel decrease with increasing amount of mBAAm.
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