title: Optimization of spinal implant screw for lower vertebra through finite element studies.
abstract: The increasing older population is suffering from an increase in age-related spinal degeneration that causes tremendous pain. Spine injury is mostly indicated at the lumbar spine (L3-L5) and corresponding intervertebral disks. Finite element analysis (FEA) is now one of the most efficient and accepted tools used to simulate these pathological conditions in computer-assisted design (CAD) models. In this study, L3-L5 spines were modeled, and FEA was performed to formulate optimal remedial measures. Three different loads (420, 490.5, and 588.6 N) based on three body weights (70, 90, and 120 kg) were applied at the top surface of the L3 vertebra, while the lower surface of the L5 vertebra remained fixed. Models of implants using stainless steel and titanium alloy (Ti6Al4V) pedicle screws and rods with three different diameters (4, 5, and 6 mm) were inserted into the spine models. The relative strengths of bone (very weak, weak, standard, strong, and very strong) were considered to determine the patient-specific effect. A total of 90 models were simulated, and von Mises stress and strain, shear stress, and strain intensity contour at the bone-implant interface were analyzed. Results of these analyses indicate that the 6-mm pedicle screw diameter is optimal for most cases. Experimental and clinical validation are needed to confirm these theoretical results.
authors.affiliation: Department of Aerospace Engineering & Applied Mechanics, Bengal Engineering & Science University, Shibpur, Howrah, India.
authors.forename: Jayanta
authors.initials: J
authors.lastname: Biswas
authors.affiliation: Department Mechanical Engineering, Bengal Engineering & Science University, Shibpur, Howrah, India.
authors.forename: Santanu
authors.initials: S
authors.lastname: Karmakar
authors.affiliation: Department of Aerospace Engineering & Applied Mechanics, Bengal Engineering & Science University, Shibpur, Howrah, India.
authors.forename: Santanu
authors.initials: S
authors.lastname: Majumder
authors.affiliation: Central Mechanical Engineering Research Institute, Durgapur.
authors.forename: Partha Sarathi
authors.initials: PS
authors.lastname: Banerjee
authors.affiliation: Biomedical Engineering Program, School of Graduate Studies; Musculoskeletal Research, Dept. Orthopaedic Surgery and Rehabilitation Medicine; Dept. Neurosurgery; Dept. Physiology and Pharmacology, SUNY Downstate Medical Center, New York, USA.
authors.forename: Subrata
authors.initials: S
authors.lastname: Saha
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation Medicine, SUNY Downstate Medical Center, USA; Department of Aerospace Engineering & Applied Mechanics, Bengal Engineering & Science University, Shibpur, Howrah, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Roychowdhury
mesh_terms: D000497:Alloys / Q000737:chemistry; D001835:Body Weight; D015519:Bone Density / Q000502:physiology; D001858:Bone Nails; D001863:Bone Screws; D000069343:Bone-Implant Interface / Q000033:anatomy & histology; D003198:Computer Simulation; D017076:Computer-Aided Design; D055119:Elastic Modulus; D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007403:Intervertebral Disc / Q000033:anatomy & histology; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000601:surgery*; D008875:Middle Aged; D008953:Models, Anatomic; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D013193:Stainless Steel; C031462:titanium alloy (TiAl6V4); D014025:Titanium