Manuel Roulaud

An Algorithmic Programming Approach for Back Pain Symptoms in Failed Back Surgery Syndrome Using Spinal Cord Stimulation with a Multicolumn Surgically Implanted Epidural Lead: A Multicenter International Prospective Study

Many studies have demonstrated the efficacy and the medical/economic value of epidural spinal cord stimulation for the treatment of “failed back surgery syndrome” (FBSS). However, the back pain component of FBSS has been recalcitrant. Recent clinical trials have suggested that multicolumn surgically implanted leads combined with enhanced programming capabilities in the newer implantable pulse generators demonstrate the ability to treat the back pain component of FBSS. The objective of our present international multicentre study is to prospectively evaluate these findings in a larger population.

Biomechanical analysis of the thoracolumbar spine under physiological loadings: Experimental motion data corridors for validation of finite element models

Biomechanical studies that involve normal, injured or stabilized human spines are sometimes difficult to perform on large samples due to limited access to cadaveric human spines and biological variability. Finite element models alleviate these limitations due to the possibility of reusing the same model, whereas cadaveric spines can be damaged during testing, or have their mechanicals behaviour modified by fatigue, permanent deformation or structural failure. Finite element models need to be validated with experimental data to make sure that they represent the complex mechanical and physiological behaviour of normal, injured and stabilized spinal segments. The purpose of this study is to characterize the mechanical response of thoracolumbar spine segments with an analytical approach drawn from experimental measurements. A total of 24 normal and fresh cadaveric thoracolumbar spine segments (T11–L3), aged between 53 and 91 years, were tested in pure flexion/extension, lateral bending and axial torsion using a specific experimental setup. Measurements of global and intervertebral angle variations were performed using three-dimensional mark tracking methods. Load/angle curves for each loading were fitted by a logarithmic approach with two coefficients. The coefficients for the functions describing the response of the spinal segments are given and constitute predictive models from experimental data. This work provides data corridors of human thoracolumbar spine motion segments subjected to pure bending in the three physiological planes. These data could be very useful to validate finite element models of the human spine.

Development of an experimental model of burst fracture with damage characterization of the vertebral bodies under dynamic conditions

Background: Burst fractures represent a significant proportion of fractures of the thoracolumbar junction. The recent advent of minimally invasive techniques has revolutionized the surgical treatment of this type of fracture. However mechanical behaviour and primary stability offered by these solutions have to be proved from experimental validation tests on cadaveric specimens. Therefore, the aim of this study was to develop an original and reproducible model of burst fracture under dynamic impact. Methods: Experimental tests were performed on 24 cadaveric spine segments (T11‐L3). A system of dynamic loading was developed using a modified Charpy pendulum. The mechanical response of the segments (strain measurement on vertebrae and discs) was obtained during the impact by using an optical method with a high‐speed camera. The production of burst fracture was validated by an analysis of the segments by X‐ray tomography. Findings: Burst fracture was systematically produced on L1 for each specimen. Strain analysis during impact highlighted the large deformation of L1 due to the fracture and small strains in adjacent vertebrae. The mean reduction of the vertebral body of L1 assessed for all the specimens was around 15%. No damage was observed in adjacent discs or vertebrae. Interpretation: With this new, reliable and replicable procedure for production and biomechanical analysis of burst fractures, comparison of different types of stabilization systems can be envisaged. The loading system was designed so as to be able to produce loads leading to other types of fractures and to provide data to validate finite element modelling. HIGHLIGHTSA specific experimental dynamic setup for spinal loading has been developed.A biomechanical analysis was performed during impact on spines from a dynamic optical method.Mechanical effects of a dynamic impact on spine were characterized by X‐ray imaging and optical analysis.A reproducible model of burst fracture on human cadaveric specimens was developed.

Multicolumn Spinal Cord Stimulation for Significant Low Back Pain in Failed Back Surgery Syndrome: A National, Multicentre, Randomized, Controlled Health Economics Study (Estimet)

Introduction Many studies have demonstrated the efficacy of spinal cord stimulation (SCS) for chronic neuropathic radicular pain over recent decades. But despite global favorable outcomes in Failed Back Surgery Syndrome (FBSS) with leg pain, the back pain component remains poorly controlled by neurostimulation. Technological and scientific progress has led to the development of new SCS leads, comprising a multicolumn design and a greater number of contacts. Their efficacy of multicolumn SCS lead configurations for the treatment of the back pain component of FBSS has recently been suggested by pilot studies. However, a randomized controlled trial must be conducted to confirm the efficacy of new generation multicolumn SCS. ESTIMET is a multicentre, randomized study designed to compare the clinical efficacy and health economics aspects of mono vs multicolumn SCS lead programming in FBSS patients with radicular pain and significant back pain. Material and Methods FBSS patients with a radicular pain VAS score ≥ 50mm, associated with a significant back pain component were recruited in 14 centers in France and implanted with multicolumn SCS. Before the lead implantation procedure, they were 1:1 randomized to monocolumn SCS (group 1) or multicolumn SCS (group 2). Programming was performed using only one column for group 1 and full use of the 3 columns for group 2. Outcome assessment was performed at baseline (pre-implantation), and 1, 3, 6 and 12 months post-implantation. The primary outcome measure was a reduction of the severity of low back pain (bVAS reduction ≥ 50%) at the 6-month visit. Additional outcome measures were changes in global pain, leg pain, paraesthesia coverage mapping, functional capacities, quality of life, neuropsychological aspects, patient satisfaction and healthcare resource consumption. Results Trial recruitment started in May 2012 and closed in October 2013. The 14 study centers have been initiated. The last visit last subject was performed in January 2015. This study received funding in 2012 from the French government NHS program “PSTIC 2011” (Program de Soutien aux Techniques Innovantes et Coûteuses). Each patient provided informed consent and approval was requested and obtained from the Poitiers University Hospital Ethics Committee (CPP Ouest III), the French National Agency for Medicines and Health Products Safety (ANSM) and the French Data Protection Authority (CNIL, No. 70108724P). Conclusion Preliminary results are expected to be analyze for the end of 2015 and published at the start of 2016.

Multicolumn Spinal Cord Stimulation Surgical Lead Implantation Using an Optic Transligamentar Minimally Invasive Technique

Introduction A new generation of neurostimulation surgical leads is used to increase the success of spinal cord stimulation (SCS) in difficult-to-treat indications such as Failed Back Surgery Syndrome (FBSS). This makes the implant procedure more invasive, which is likely to be a determinant factor in clinical and functional outcomes. Minimal access spinal technologies (MAST) have been previously used for surgical lead implantation. However, only a unilateral approach was described, causing some difficulties for median lead placement and not always preventing laminectomy. A recent MAST technique can be used to implant SCS leads without these limitations, which seems to be key in the positive outcomes experienced. The objective is to describe the original MAST technique used in the pilot study. Material and Methods Twenty-four consecutive patients were implanted with a multicolumn surgical lead for refractory chronic back and leg pain using the optic transligamentar MAST technique described extensively. Clinical outcomes, functional ability and adverse events (AEs), were recorded for up to 12 months after surgery. Results The MAST technique allowed median lead placement, facilitated visualization of the spine and permitted transligamentar insertion that minimized scarring and muscle damage, intraoperative blood loss and postoperative functional complications. Back pain decreased significantly at all follow-up, while functional status improved significantly at 1 year. No technique-related AEs were reported. Conclusion Use of MAST approach could be useful in safe implantation of multicolumn surgical leads and confer major advantages in difficult-to-treat refractory lower back pain conditions such as FBSS

Composante lombaire des lomboradiculalgies : intérêt de la neurostimulation ?

Les lombalgies affectent ou ont affecte plus des trois quarts des Francais [1]. Chez 10 % des patients, les lombalgies ne persistent pas plus de six semaines alors que, chez 7 % des patients, elles prendront un caractere chronique. Ce groupe de patients represente plus de 70 % du cout lie a cette pathologie. La lombalgie chronique represente un reel fleau et un defi pour nos societes. Dans ce contexte, certaines symptomatologies douloureuses lombaires apparaissent dans les suites d’une ou de plusieurs chirurgies rachidiennes ou bien elles peuvent se presenter comme une acutisation postoperatoire de lombalgies preexistantes. Elles sont alors souvent associees a des radiculalgies chroniques, a caractere neuropathique, on parle ainsi de lomboradiculalgies postoperatoires (LRPO). Les patients souffrant de LRPO correspondent a un groupe tres heterogene, avec des etiologies complexes et variees, necessitant une prise en charge pluridisciplinaire etoffee, pour permettre de definir un schema therapeutique optimal [2]. Malgre l’evolution parfois pejorative de ces douleurs pouvant devenir, a terme, refractaires aux differents traitements antalgiques medicamenteux ou prises en charges non invasives instaurees, plusieurs etudes ont demontre l’efficacite et la pertinence medico-economique de la stimulation medullaire epidurale (SME) pour le traitement de ces douleurs [3].