Robert Rizza, Ph.D.
Professor
- Milwaukee WI UNITED STATES
- Allen Bradley Hall of Science: S125C
- Mechanical Engineering
Dr. Robert Rizza specializes in engineering solutions to problems in pediatric orthopedics.
Multimedia
Education, Licensure and Certification
Ph.D.
Mechanical Engineering
Illinois Institute of Technology
1995
M.S.
Mechanical and Aerospace Engineering
Illinois Institute of Technology
1989
B.S.
Mechanical and Aerospace Engineering
Illinois Institute of Technology
1987
Biography
Areas of Expertise
Accomplishments
Oscar Werwath Researcher of the Year Award, MSOE
2010
Falk Engineering Educator Award
2008
Affiliations
- Society of Automotive Engineers (SAE), North Central Chapter Board of Governors : Member
- American Society of Mechanical Engineers (ASME) : Member
- Sigma Psi : Member
Event and Speaking Appearances
A Custom Contoured Surgical Pillow to Reduce Snoring
2017 Design of Medical Devices Conference Minneapolis, Minnesota
2017-04-10
Novel Pedorthosis for Pediatric Flatfoot using Dynamic Fluoroscopy and Plantar Pressure Assessment
GCMAS 2016 Annual Conference Memphis, Tennessee
2016-05-17
Does Casting with Window Cut Affect Biomechanical Strength in Treatment of Children with Scoliosis?
GCMAS 2016 Annual Conference Banff, California
2016-05-25
Impacts of Different torques on Remodeling of the Caudal Vertebral Growth Plate
SOSORT-IRSSD Conference Banff, California
2016-05-25
Validation of Dynamic Pedorthiosis in the Treatment of Clubfoot
ORS 58th Annual Meeting San Francisco, California
2012-02-04
Changes in the COP Trajectory after use of a CAD and FEA Designed Orthotic
2011 ASME Summer Bioengineering conference, Farmington, Pennsylvania
2011-06-22
Impact of Individualized Pedorthosis on Plantar Pressures and Functional Outcomes for Chidren with Clubfoot
GCMAS 2011 Annual conference, Bethesda, Maryland
2011-04-26
Effectiveness of a New Dynamic Pedorthosis with Wedge on the Clubfoot
New Orleans, Louisiana ORS 56th Annual Meeting
2010-03-06
Effect of Torque on Spinal Growth Asymmetry
Third International Conference on Mechanics of Biomaterials & Tissues Clearwater Beach, Florida
2009-12-13
Research Grants
Customized Orthotic for Severe Planovalgus Foot Deformity in Children
National Institute on Disability and Rehabilitation Research
Oct 2012 - Sept 2015
Development of a Fluid Powered Expandable Rod System
Otto Maha Faculty Research Fellowship
2008
Development of Dynamic Pedorthosis for Improving Clubfoot Correction
National Institute on Disability and Rehabilitation Institute (NIDRR)
CO-PI: Dr. Xue-Ceng Liu, Medical College of Wisconsin.
Software Grant
ACIS-3D CAD Software From Spatial Technology
2001
The Undergraduate Vibration Analysis Laboratory at NDSU
3M Company
1995
Selected Publications
Optimal thickness for additive manufactured brace
Scoliosis and Spinal DisordersRobert Rizza, Xue-Cheng Liu, John Thometz, Vince Anewenter
2018
Considering implementation of computerized models which predict the functional behavior of the brace a priori, questions are raised as why these same computerized methods cannot be used to manufacture the brace.
There is much interest in using Additive Manufacturing (AM), a 3D printing method, as this approach is a minimal hands-on very accurate method that may generate brace with a very short technician involvement time (as little as 0.5-2.5 hours). However, to make full benefit of AM the brace needs to be designed for manufacturing with AM in addition to being designed to provide the proper constraint forces.
Traditionally manufactured braces are made of Polyethylene (PE). Many original AM materials have less endurance, are more brittle, and have less flexibility and rigidity than PE. However, there are many new AM materials which compare favorably to PE.
Fluoroscopy and Dynamic Pressure-based Foot Orthoses for Children with Flatfoot
Journal of Prosthetics and OrthoticsX.C., Rizza, R
2018
A wide variety of braces are commercially available designed for the adolescent idiopathic scoliosis (AIS), but very few braces for infantile scoliosis (IS) or juvenile scoliosis (JS). The goals of this study were: 1) to briefly introduce an elongation bending derotation brace (EBDB) in the treatment of IS or JS; 2) to investigate changes of Cobb angles in the AP view of X-ray between in and out of the EBDB at 0, 3, 6, 9, and 12 months; 3) to compare differences of Cobb angles (out of brace) in 3, 6, 9, and12 month with the baseline; 4) to investigate changes (out of brace) in JS and IS groups separately.
Effect of an elongation bending derotation brace on the infantile or juvenile scoliosis
Scoliosis and Spinal DisordersThometz, J., X.C. Liu, X.C., Rizza, R., English, I., and Tarima, S
2018
A wide variety of braces are commercially available designed for the adolescent idiopathic scoliosis (AIS), but very few braces for infantile scoliosis (IS) or juvenile scoliosis (JS). The goals of this study were: 1) to briefly introduce an elongation bending derotation brace (EBDB) in the treatment of IS or JS; 2) to investigate changes of Cobb angles in the AP view of X-ray between in and out of the EBDB at 0, 3, 6, 9, and 12 months; 3) to compare differences of Cobb angles (out of brace) in 3, 6, 9, and12 month with the baseline; 4) to investigate changes (out of brace) in JS and IS groups separately.
Impacts of different torques on remodeling of the caudal vertebral growth plate
Scoliosis and Spinal DisordersXueCheng Liu, Robert Rizza, John Thometz, Derek Rosol, Channing Tassone, Sergey Tarima, Paula North
2017
Numerous studies indicate that longitudinal loading affects the vertebral growth plate and disc leading to vertebral wedging deformation. Torsional loading impacts disc gene expression and annular stiffness. However, its effect on chondrocytes in the growth plate (longitudinal and circumferential growth) has not been investigated, let alone the comparisons between static loading and dynamic loading in the asymmetric remodeling of the caudal vertebra.
A New Gait Data Designed Orthotic for Flatfoot
Journal of Medical DevicesRizza, R. and Liu, X.C.
2016
Pediatric pes planus, or flatfoot, is a common foot condition in children. Flatfoot is caused by loss of the medial longitudinal arch. There may be associated anatomical abnormalities, such as valgus position of the heel, medial rotation of the talus, and medial talar prominence. The incidence among children with flatfoot varies from 2.8% to 24.2%.
Treatment for symptomatic flatfoot begins conservatively with shoe modification and supportive footwear and arch supports. However, these methods do not affect the course of flatfoot in children and have a limited evidence of correction of foot pronation. The traditional method for designing a flatfoot insert is based on the experience level of the orthotist using data that are nonweight bearing.
However, a biomechanical study showed a medial shift of the center of pressure (COP) trajectory, which is a kinetic gait based measure. In addition, the fluoroscopic method provides a 2D assessment in the sagittal plane during the second rocker in stance phase, including the navicular height and talar alignment or subtalar angles. In particular, the navicular height has been shown to have a strong correlation with flatfoot deformity. Thus, a new design procedure using gait-based measures should be possible.
Development of an Adjustable Sinus Tarsi Device for Flatfoot Correction: A Pilot Study in a Sawbones Model
Journal of Medical DevicesRobert Rizza, XueCheng Liu, Scott Van Valin, Roger Lyon
2014
Pediatric pes planus (flatfoot) is a common foot condition caused by loss of the medial longitudinal arch. There may be associated with anatomical abnormalities such as valgus position of the hindfoot, an internal rotation of the talus and medial talar prominence. The incidence among children with flatfoot varies from 2.8% to 24.2%. If nonsurgical interventions have failed to address deformities surgical treatments will be indicated and arthroereisis is the preferred method.
Despite the fact that arthroereisis limits talocalcaneal joint motion with an implant in the sinus tarsi, it has proven to be effective in reducing pain. The implant neutralizes the abnormal pronation associated with pes planus. Numerous studies have shown the effectiveness of these implants. However, there are still many cases of inadequate results from the including: prosthesis migration, continued severe postoperative pain, failure to reform the medial longitudinal arch on weight-bearing, avascular necrosis, sinus tarsitis, and subluxation of the prosthesis, which may be associated with incorrect sizing of the implant for the subtalar arthroereisis.
Based upon computed tomography-scan data, an adjustable expandable implant has been designed and tested by the investigators to maximize the space at the subtalar joint and provide maximal correction. It is hypothesized that use of the implant will lead to improvement of anatomic malalignment, change in range of motion on the foot segments and the ankle joint, and lateral shifting of the center of pressure (COP). A study has been carried out to validate the device by comparing changes in the motion of the foot segments and plantar pressure distribution using a Sawbones model.
A Cancellous Bone Screw With Adjustable Holding Power
Journal of Medical DevicesRizza, R., Liu, X., Van Valin, S.
2013
Different types of screws are present in practice today including cortical, cancellous, cannulated, Herbert, Malleolar, and pedicle. Each of these types of orthopedic bone screws are used depending on type of fracture, as well as the type of bone in the fracture. The proper use of these screws is important to the healing and union of bone.
Mechanics and Validation of an in Vivo Device to Apply Torsional Loading to Caudal Vertebrae
Journal of Biomechanical EngineeringRizza, R., Liu, X.
2013
Axial loading of vertebral bodies has been shown to modulate growth. Longitudinal growth of the vertebral body is impaired by compressive forces while growth is stimulated by distraction. Investigations of torsional loading on the growth plate in the literature are few. The purposes of this study were two-fold: (1) to develop a torque device to apply torsional loads on caudal vertebrae and (2) investigate numerically and in vivo the feasibility of the application of the torque on the growth plate. A controllable torque device was developed and validated in the laboratory. A finite element study was implemented to examine mechanically the deformation of the growth plate and disk. A rat tail model was used with six 5-week-old male Sprague-Dawley rats. Three rats received a static torsional load, and three rats received no torque and served as sham control rats. A histological study was undertaken to investigate possible morphological changes in the growth plate, disk, and caudal bone. The device successfully applied a controlled torsional load to the caudal vertebrae. The limited study using finite element analysis (FEA) and histology demonstrated that applied torque increased lateral disk height and increased disk width. The study also found that the growth plate height increased, and the width decreased as well as a curved displacement of the growth plate. No significant changes were observed from the in vivo study in the bone. The torsional device does apply controlled torque and is well tolerated by the animal. This study with limited samples appears to result in morphological changes in the growth plate and disk. The use of this device to further investigate changes in the disk and growth plate is feasible.
The in-vivo effect of torque on growth in caudal vertebrae.
Studies in Health Technology and InformaticsRizza, R., Liu, X.C., Thometz, J.
2012
Numerous studies involving axial distraction and compression of the spine indicate that longitudinal loading affects the vertebral growth plate as well as modulation of spinal growth. Furthermore, asymmetric loading is involved in curve progression as a result of vertebral bone changes and disc wedging. As with longitudinal loading, direct or indirect application of torque to the growth plate may have an influence as well. A study was undertaken to develop a fixture that may be applied in-vivo to generate controlled torsional loads and to examine the effect of such torsional loads on the growth plate in caudal vertebrae. It is shown that application of torque leads to curvature in the morphology of the growth plate, a reduced width (medial to lateral distance of the growth plate) and remarkably increased thickness (height of 3 physeal zones in the growth plate) and dramatically widened disc space.
A New Method in the Design of a Dynamic Pedorthosis for Children With Residual Clubfoot
Journal of Medical DevicesRizza, R., Liu, X., Thometz, J., Lyon, R., Tassone, C.
2010
Clubfoot is a common pediatric orthopaedic deformity. Despite the popularity of Ponseti’s method and night splints such as the Denis–Browne method, there is still an 11–47% rate of deformity relapse reported in the literature. The technique to make traditional orthotics is dependent on a nonweight-bearing casting or foot imprint. These splints outdate clinical treatment trends and only apply to patients who are of nonwalking age. This study shows that a new procedure utilizing computer aided design and the finite element method can be employed to develop a customized weight-bearing dynamic orthotic. In addition, the plantar pressure distribution and the trajectory of the center of this pressure distribution are used to design the orthotic. It is shown that the trajectory of the center of pressure, traditionally used in gait analysis, can be used not only to quantify the severity of the foot deformity but to design a custom orthotic as well. Also, the new procedure allows the custom orthotic to be designed and analyzed within a day. The new orthotic design is composed of soft foam interior layers and a polymer supportive exterior layer. It is proved that rapid prototyping technologies employing selective laser sintering can be used to construct these layers to produce a custom orthotic within a 24 h time frame.
Effectiveness of a New Dynamic Pedorthosis with Wedge on the Clubfoot
Foot and Ankle InternationalRizza, R., Liu, X.C., Thometz, J., Lyon, R., Tassone, C., Harris, G.
2010
Surgical Pillow Design by Optimal Head and Pillow Alignment
Journal of Medical DevicesRobert Rizza, XueCheng Liu, Zhiyuan Yang, William Clarke, Channing Tassone
2015
Commercial donut pillows are used during lengthy surgical operations. With the patient anesthetized, the multiple pressure points on the head and wrinkling of the skin cut off blood circulation in the face, which leads to facial decubitus ulcers.
Foam materials, which are used in these pillows, are very effective in reducing pressure points by transferring pressure into shear stress. However, this same shear stress leads to wrinkling of the skin which generates sores.
From the point of view of the pillow mechanics, pressure normal to the pillow surface is related to normal stress in the pillow. Reduction of this normal stress implies a reduction in pressure points and an increase in shear stress. However, an increase in the shear stress leads to increased wrinkling of the skin. Thus, the optimal pillow design, which reduces sores due to pressure points and wrinkling, would be characterized by the design where optimal values of the normal and shear stress are obtained.
The optimal values in the normal and shear stress are affected by the orientation of the pillow with respect to the patient's face. Thus in order to find the optimal pillow design, a relationship between head orientation and pillow surface geometry must also be established.
The objective of this study was to design a custom surgical pillow by establishing optimal normal shear and stress components with respect to varying head orientations.
