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Bone & Joint Research
Vol. 10, Issue 12 | Pages 797 - 806
8 Dec 2021
Chevalier Y Matsuura M Krüger S Traxler H Fleege† C Rauschmann M Schilling C

Aims

Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques.

Methods

Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S4). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads.


The Bone & Joint Journal
Vol. 102-B, Issue 1 | Pages 5 - 10
1 Jan 2020
Cawley DT Rajamani V Cawley M Selvadurai S Gibson A Molloy S

Aims

Intraoperative 3D navigation (ION) allows high accuracy to be achieved in spinal surgery, but poor workflow has prevented its widespread uptake. The technical demands on ION when used in patients with adolescent idiopathic scoliosis (AIS) are higher than for other more established indications. Lean principles have been applied to industry and to health care with good effects. While ensuring optimal accuracy of instrumentation and safety, the implementation of ION and its associated productivity was evaluated in this study for AIS surgery in order to enhance the workflow of this technique. The aim was to optimize the use of ION by the application of lean principles in AIS surgery.

Methods

A total of 20 consecutive patients with AIS were treated with ION corrective spinal surgery. Both qualitative and quantitative analysis was performed with real-time modifications. Operating time, scan time, dose length product (measure of CT radiation exposure), use of fluoroscopy, the influence of the reference frame, blood loss, and neuromonitoring were assessed.


The Bone & Joint Journal
Vol. 100-B, Issue 2 | Pages 219 - 225
1 Feb 2018
Yoo JU McIver TC Hiratzka J Carlson H Carlson N Radoslovich SS Gernhart T Boshears E Kane MS

Aims

The aim of this study was to determine if positive Waddell signs were related to patients’ demographics or to perception of their quality of life.

Patients and Methods

This prospective cross-sectional study included 479 adult patients with back pain from a university spine centre. Each completed SF-12 and Oswestry Disability Index (ODI) questionnaires and underwent standard spinal examinations to elicit Waddell signs. The relationship between Waddell signs and age, gender, ODI, Mental Component Score (MCS), and Physical Component Score (PCS) scores was determined.


Bone & Joint Research
Vol. 7, Issue 1 | Pages 28 - 35
1 Jan 2018
Huang H Nightingale RW Dang ABC

Objectives

Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine.

Methods

A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion.


The Bone & Joint Journal
Vol. 98-B, Issue 2 | Pages 238 - 243
1 Feb 2016
Qian L Li P Wu W Fang Y Zhang J Ouyang J

Aims

This study aimed to determine the relationship between pedicle-lengthening distance and bulge-canal volume ratio in cases of lumbar spinal stenosis, to provide a theoretical basis for the extent of lengthening in pedicle-lengthening osteotomies.

Methods

Three-dimensional reconstructions of CT images were performed for 69 patients (33 men and 36 women) (mean age 49.96 years; 24 to 81). Simulated pedicle-lengthening osteotomies and disc bulge and spinal canal volume calculations were performed using Mimics software.