Single-Level In Vitro Kinematic Comparison of Novel Inline Cervical Interbody Devices With Intervertebral Screw, Anchor, or Blade.
Global spine journal
2019; 9 (7): 697–707
Study Design: In vitro cadaveric biomechanical study.Objective: To compare the biomechanics of integrated anchor and blade versus traditional screw fixation techniques for interbody fusion.Methods: Fifteen cadaveric cervical spines were divided into 3 equal groups (n = 5). Each spine was tested: intact, after discectomy (simulating an injury model), interbody spacer alone (S), integrated interbody spacer (iSA), and integrated spacer with lateral mass screw and rod fixation (LMS+iS). Each treatment group included integrated spacers with either screw, anchor, or blade integrated spacers. Constructs were tested in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) under pure moments (±1.5 Nm).Results: Across all 3 planes, the following range of motion trend was observed: Injured > Intact > S > iSA > LMS+iS. In FE and LB, integrated anchor and blade significantly decreased motion compared with intact and injured conditions, before and after supplemental posterior fixation (P < .05). Comparing tested devices revealed biomechanical equivalence between screw, anchor, and blade fixation methods in all loading modes (P > .05).Conclusion: All integrated interbody devices reduced intact and injured motion; lateral mass screws and rods further stabilized the single motion segment. Comparing screw, anchor, or bladed integrated anterior cervical discectomy and fusion spacers revealed no significant differences.
View details for DOI 10.1177/2192568219833055
View details for PubMedID 31552149
- Reliability of radiological measurements of type 2 odontoid fracture SPINE JOURNAL 2019; 19 (8): 1324–30
Reliability of Radiological Measurements of Type-2 Odontoid Fracture.
The spine journal : official journal of the North American Spine Society
It is recognized that radiological parameters of type 2 dens fractures, including displacement and angulation, are predictive of treatment outcomes and are used to guide surgical decision-making. The reproducibility of such measurements, therefore, is of critical importance. Past literature has shown poor inter-observer reliability for both displacement and angulation measurements of type 2 dens fractures. Since such studies however, various advancements of radiological review systems and measurement tools have evolved to potentially improve such measurements.To re-examine the interrater reliability of measuring displacement and angulation of type 2 dens fractures utilizing modern radiologic review systems. Besides quantitative measurements, the reliability of raters in identifying diagnostic classifications based on translational and angulational displacement was also examined.Radiographic measurement reliability and agreement study.Thirty-seven patients seen at a single institution between 2002 and 2017 with primary diagnosis of acute type II dens fracture with complete CT imaging.Radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cut-off points were also recorded.Measurements were performed by five surgeons with varying years of experience in spine surgery using the hospital's electronic medical record radiological measuring tools. The radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cut-off points were also recorded. Each rater received a graphic demonstration of the measurement methods, but had the autonomy to select a best cut from the sagittal CT to measure. All raters were blinded to patient information.Measurements for displacement and angulation among the five raters demonstrated "excellent" reliability. Intra-rater reliability was also "excellent" in measuring displacement and angulation. The reliability of diagnostic classification of displacement (above vs. below 5mm), was found to be "very good" among the raters. The reliability of diagnostic classification of angulation (above vs. below 11°) demonstrated "good" reliability.Advancement of radiological review systems, including review tools and embedded image processing software, has facilitated more reliable measurements for type-2 odontoid fractures.
View details for PubMedID 31078698
Complete Atlantoaxial Dislocation After Odontoid Synchondrosis Fracture: A 2-Year Follow-up Study: A Case Report.
JBJS case connector
Spine injuries are rare in children, but when they do occur, the synchondrosis of C2 may be involved. A 5-year-old boy presented to our clinic complaining of neck pain for 6 weeks, which started after wrestling with peers. He had slight upper extremity weakness, clonus, and diminished reflexes. Imaging, including computed tomography and magnetic resonance imaging scans, showed a fracture dislocation through the synchondrosis of the odontoid. The patient was initially treated with admission to the hospital, awake halo placement, and gradual traction over a few days. Subsequently, he was taken for transoral reduction and posterior instrumented fusion of C1-C3 using a combination of sublaminar suture, screws, and rods. Most recently, he was doing well over 2 years later, with no residual neurologic symptoms.The case presented demonstrates one option for an otherwise nonreducible odontoid synchondrosis fracture with complete atlantoaxial dislocation: transoral reduction and open posterior instrumentation. This proved to be a practical technique and provided a good clinical result in this case. These injuries are rare, but when they do occur, the examination can be surprisingly subtle given the severity of the injury. Plain films should be scrutinized carefully and advanced imaging obtained when necessary to confirm the diagnosis.
View details for DOI 10.2106/JBJS.CC.18.00327
View details for PubMedID 31188795
The Effects of Varenicline on Lumbar Spinal Fusion in a Rat Model.
The spine journal : official journal of the North American Spine Society
Smoking is detrimental to obtaining a solid spinal fusion mass with previous studies demonstrating its association with pseudoarthrosis in patients undergoing spinal fusion. Varenicline is a pharmacologic adjunct used in smoking cessation which acts as a partial agonist of the same nicotinic receptors activated during tobacco use. However, no clinical or basic science studies to date have characterized if varenicline has negative effects on spinal fusion and bone healing by itself.Our study aim was to elucidate whether varenicline affects the frequency or quality of posterolateral spinal fusion in a rodent model at an endpoint of 12 weeks.Randomized control trial PATIENT SAMPLE: 14 male Lewis rats randomly separated into two experimental groups OUTCOME MEASURES: Manual palpation of fusion segment, radiography, μCT imaging, 4-point bend.Fourteen male Lewis rats were randomly separated into two experimental groups undergoing L4-5 posterior spinal fusion procedure followed by daily subcutaneous injections of human dose varenicline or saline (control) for 12 weeks post-surgery. Spine samples were explanted, and fusion was determined via manual palpation of segments by two independent observers. High-resolution radiographs were obtained to evaluate bridging fusion mass. μCT imaging was performed to characterize fusion mass and consolidation. Lumbar spinal fusion units were tested in 4-point bending to evaluate stiffness and peak load. Study funding sources include $5000 OREF Grant. There were no applicable financial relationships or conflicts of interest.At three months post-surgery, 12 out of 14 rats demonstrated lumbar spine fusion (86% fused) with no difference in fusion frequency between the varenicline and control groups as detected by manual palpation. High resolution radiography revealed six out of seven rats (86%) having complete fusion in both groups. μCT showed no significant difference in bone mineral density or bone fraction volume between groups in the region of interest. Biomechanical testing demonstrated no significant different in the average stiffness or peak loads at the fusion site of the varenicline and control groups.Based on the results of our rat study, there is no indication that varenicline itself has a detrimental effect on the frequency and quality of spinal fusion.
View details for DOI 10.1016/j.spinee.2019.07.015
View details for PubMedID 31377475
Intraoperative load-sensing drives the level of constraint in primary total knee arthroplasty: Surgical technique and review of the literature.
Journal of clinical orthopaedics and trauma
2017; 8 (3): 265–69
Total knee arthroplasty is a traditional surgical procedure aimed to restore function and relief pain in patients with severe knee osteoarthritis. Recently, many medial pivot knee systems were deigned to replicate the normal knee kinematic: a highly congruent medial compartment and a less conforming lateral tibial plateau characterize these devices. A slightly asymmetric soft tissue balancing is mandatory using medial pivot designs to obtain a correct and physiological knee biomechanics leading good outcomes and long survival rates. This article describes a new surgical technique using a modern third generation TKA design combined with wireless load-sensor tibial trials to improve the correct knee load balancing with a minimal conformity of the polyethylene insert. The use of wireless load-sensing tibial trials has several benefits: it is an intraoperative, objective and dynamic tool allowing surgeons to optimize in real time soft tissue balancing. The meaning of a "truly balanced knee" is still a controversial issue in the current literature.
View details for PubMedID 28951645