The level of agreement between the numerical rating scale and visual analogue scale for assessing pain intensity in adults with chronic pain.

The numerical rating scale and visual analogue scale are used to quantify pain intensity. However, it has not yet been explored whether these scores are interchangeable in adults with chronic pain. Data from the prospective multicentre cross-sectional INTERVAL study were used to evaluate the one-dimensionality and agreement between numerical rating scale scores and visual analogue scale scores in adults with chronic pain. Pain intensity scores using the numerical rating scale and visual analogue scale were provided by 366 patients with chronic pain for current, average, minimal and maximal pain. To evaluate whether pain intensity scales are completed in accordance with each other, the proportion of patients who satisfied the following condition was calculated: minimal pain intensity ≤ maximal pain intensity. A factor analysis confirmed the one-dimensionality of the pain measures. A significant difference was found between numerical rating scale and visual analogue scale scores for average, current, minimum and maximum pain. Intra-class correlation coefficient estimates ranged from 0.739 to 0.858 and all measures failed to show sufficient and acceptable agreement at the 95% level. The strength of agreement between pain severity categories was classified as 'moderate' for average and minimal pain and 'substantial' for current and maximal pain. The proportion of patients who scored minimal pain ≤ maximal pain was 97.5% for the numerical rating scale and 89.5% for the visual analogue scale. This study failed to show an acceptable agreement between the numerical rating scale and visual analogue scale when pain intensity was rated by adults with chronic pain, despite showing both scales measure the same information.

Contribution of Minimally Invasive Bone Augmentation With PMMA Cement in Primary Fixation of Schatzker Type II Tibial Plateau Fractures.

Background: The most common type of fracture of the lateral tibial plateau is the Schatzker type II split-depressed fracture. Minimally invasive surgery using balloon reduction appears to be very promising compared to the gold standard using a bone tamp. This surgery aims to have the best reduction and stabilization to benefit from an early passive and active rehabilitation to avoid stiffening and muscle wasting. Using a balloon for fracture reduction has allowed the use of semi-liquid Injectable Bone Cement (IBC) fillers. These fillers can be phosphocalcic or polymethyl methacrylate (PMMA). The latest recommendations on these IBCs in spinal surgery increasingly rule out phosphocalcic fillers because of their low mechanical strength. Questions/purposes: 1) What is the mechanical influence of IBC filling (PMMA) regarding the split and depression components of a Schatzker type II fracture? 2) What is the mechanical influence of osteosynthesis regarding the split and depression components of a Schatzker type II fracture with or without PMMA filing in three different kinds of percutaneous fixations? Methods: This biomechanical study was performed on 36 fresh frozen tibia/fibula specimens. Six groups were formed according to the type of percutaneous osteosynthesis or possible PMMA filling. Mechanical strength tests were carried out using a Unicompartmental Knee prosthesis and displacement components were measured on either side of the separation on the anterolateral facet by optical method. Results: We found a significant difference between cementless and cemented osteosynthesis for depression fracture stabilization (difference -507.56N with 95% confidence interval [-904.17; -110.94] (p-value = 0.026)). The differences between the different types of osteosynthesis were not significant (p-value = 0.58). There was a significant difference between osteosynthesis without cement and osteosynthesis with cement on separation (difference -477.72N [-878.52; -76.93] (p-value = 0.03)). The differences between the different types of fixations were not significant regarding separation (p-value = 0.99). Conclusion: PMMA cement significantly improves primary stability, regardless of the type of osteosynthesis for a Schatzker type II plateau fracture. Filling with PMMA cement during tuberoplasty seems to be a very promising strategy in association with percutaneous osteosynthesis to allow rapid recovery after surgery.

Fracture behavior of cancellous bone and cancellous bone-PMMA bone cement interface: An experimental study using an integrated methodology (wedge splitting test and Heaviside-based digital image correlation).

Minimally invasive methods, such as balloon kyphoplasty (BKP) and percutaneous sacroplasty (PS), which are now widely used for the surgical treatment of compression fractures, involve injection of a bolus of poly (methyl methacrylate) bone cement (hereafter, "bone cement") into the fractured tissue. Many of the common complications following these surgeries, such as cement leakage and adjacent-level fractures (in the case of BKP), have been postulated to be related to the quality of the cancellous bone-bone cement interface, which, in turn, is a function of its fracture resistance. It is common to use bovine cancellous bone or polyurethane foam (PF) as a substitute for human cancellous bone in biomechanical studies of these surgical methods. The literature is lacking in studies of determination of fracture properties of human cancellous bone-bone cement interface, bovine cancellous bone-bone cement interface, and PF-bone cement interface. In the present work, an integrated methodology (combination of wedge splitting test and Heaviside-based digital image correlation) was used to make these determinations as well as those for the bone cement, bones and the PF alone. The fracture properties determined were maximum fracture load (Fmax), fracture toughness (Kc), and specific fracture energy (Gf). For example, Gf values for human cancellous bone and human cancellous bone-bone interface were 0.48±0.14 N/mm and 0.38±0.05 N/mm, respectively, whereas in the case of bovine cancellous bone and bovine cancellous bone-bone cement interface, they were 1.08±0.11 N/mm and 0.22±0.05 N/mm, respectively, and for PF (Grades 12.5 and 15.0) and PF-bone cement interface, they were 0.81±0.12 and 0.55±0.06 N/mm, respectively. The same trends were seen in the Fmax and Kc results. These results suggest that it may not be justified to use either bovine cancellous bone or either of the PF grades as a substitute for human cadaveric cancellous bone in biomechanical studies of BKP, PS, and similar surgical methods.

Evaluation of fracture properties of cancellous bone tissues using digital image correlation/wedge splitting test method.

The fracture mechanics (FM) parameters of cancellous bone tissues are very important from a clinical point of view especially for the bone cement augmentation. From the literature review, one can observe that the experimental determination of fracture mechanic parameters of cancellous bone are still lacking. This can be due to the conditions associated with the unstable crack propagation in the cancellous bone and lack of tools to extract and measure the parameters (like crack opening displacement (COD) and crack length) in the course of fracture tests, which are necessary to evaluate the fracture properties. To address above mentioned, a platform was developed integrating an optical measurement technique like digital image correlation (DIC) with classical wedge splitting test (WST) method to extract precise and real crack tip positions, crack opening displacement (COD) at each load step. These indeed used for the evaluation of the fracture mechanic properties (fracture toughness, specific fracture energy (Gf)) of the cancellous bone. Two approaches were used to evaluate the fracture mechanic properties of the bone. The first method is based on the global approach, which was widely used in the literature and the second method is based on the local approach. In this local approach, the local fracture energy (Gi) during the course of the test was evaluated, which give access to local fracture mechanics. The results evaluated by both the methods were in good accordance and compared with available literature. In addition, an attempt made to retrieve the real crack tip position at each load step during the test.

Contribution of minimally invasive bone augmentation to primary stabilization of the osteosynthesis of Schatzker type II tibial plateau fractures: Balloon vs bone tamp.

BACKGROUND: Schatzker type II tibial plateau fractures necessitate the least invasive treatment possible. Arthroscopic reduction by bone tamp followed by osteosynthesis is the current gold standard for this type of tibial plateau fracture. The objective of this study was to compare this technique to anterior approach tuberoplasty with balloon reduction. The comparison criteria were residual articular step off, metaphyseal cavity volume formed during reduction, and mechanical strength to separation and to depression displacement. METHODS: Fractures were created on 12 human cadaveric tibiae and reduced by a minimally invasive approach in six specimens by a balloon, and by bone tamp in the six others. Articular step off and metaphyseal-epiphyseal cavity volume were measured by TDM. Mechanical tests were performed up to assembly failure to characterize structural strength. Secondary displacements, fracture depression displacement and separation were measured by optical methods. FINDINGS: There was no significant difference in step off measurement after balloon reduction or bone tamp (0.29 cm vs 0.37 cm; p = 0.06). The cavity volume formed by balloon reduction was significantly smaller than the volume created by bone tamp reduction (0.45 cm3 vs 5.12 cm; p = 0.002). The compressive load required for assembly failure was significantly greater in the balloon group than in the bone tamp group (1210.17 N vs 624.50 N; p = 0.015). INTERPRETATION: There exists a correlation between load to failure of the assembly frame and the metaphyseal volume required for bone fracture reduction. The minimally invasive balloon technique has fewer negative effects on the osseous stock, thereby enabling better primary structural strength of the fracture.

Utility of cement injection to stabilize split-depression tibial plateau fracture by minimally invasive methods: A finite element analysis.

BACKGROUND: Treatment for fractures of the tibial plateau is in most cases carried out by stable fixation in order to allow early mobilization. Minimally invasive technologies such as tibioplasty or stabilization by locking plate, bone augmentation and cement filling (CF) have recently been used to treat this type of fracture. The aim of this paper was to determine the mechanical behavior of the tibial plateau by numerically modeling and by quantifying the mechanical effects on the tibia mechanical properties from injury healing. METHODS: A personalized Finite Element (FE) model of the tibial plateau from a clinical case has been developed to analyze stress distribution in the tibial plateau stabilized by balloon osteoplasty and to determine the influence of the cement injected. Stress analysis was performed for different stages after surgery. FINDINGS: Just after surgery, the maximum von Mises stresses obtained for the fractured tibia treated with and without CF were 134.9 MPa and 289.9 MPa respectively on the plate. Stress distribution showed an increase of values in the trabecular bone in the treated model with locking plate and CF and stress reduction in the cortical bone in the model treated with locking plate only. INTERPRETATION: The computed results of stresses or displacements of the fractured models show that the cement filling of the tibial depression fracture may increase implant stability, and decrease the loss of depression reduction, while the presence of the cement in the healed model renders the load distribution uniform.

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.

Operating environment for awake brain surgery - Choice of tests.

INTRODUCTION: The indication for awake brain surgery depends on a prerequisite, i.e. recognition that the brain area concerned is truly eloquent, and identification of one or more functions that must be preserved. These functions are determined preoperatively in collaboration with the patient, and neuropsychological tests considered to be the most relevant are performed in the operating room according to each team's technical preferences. OPERATING ENVIRONMENT: The neurosurgeon must choose transfer equipment considered to be relevant. Although a minimal technological environment is an option, a surgical team with great human wealth is essential, composed of specialized personnel with complementary skills. CHOICE AND IMPLEMENTATION OF INTRAOPERATIVE TESTS: The choice of intraoperative tests, which can be relatively simple for certain primary functions, can be much more difficult for high-level cognitive functions. No consensus has been reached concerning these tests, which must therefore be selected on an individual basis. Intraoperative testing must be based on preoperative multidisciplinary decisions made jointly by the neurosurgeon, neurologist, speech therapist and neuropsychologist. CONCLUSIONS: Numerous operating tools and technology transfers are available for neurosurgical teams performing awake brain surgery but none - or very few - of them constitutes a mandatory prerequisite. In contrast, the transition from the concept of eloquent brain area to that of brain functions that must be preserved requires highly skilled multidisciplinary human resources. This goal will be more likely achieved in centers highly specialized in functional oncological neurosurgery.

A novel approach for biomechanical spine analysis: Mechanical response of vertebral bone augmentation by kyphoplasty to stabilise thoracolumbar burst fractures.

Kyphoplasty has been shown as a well-established technique for spinal injuries. This technique allows a vertebral bone augmentation with a reduction of morbidity and does not involve any adjacent segment immobilisation. There is a lack of biomechanical information resulting in major gaps of knowledge such as: the evaluation of the "quality" of stabilisation provided by kyphoplasty as a standalone procedure in case of unstable fracture. Our objective is to analyse biomechanical response of spine segments stabilised by Kyphoplasty and PMMA cement after experiencing burst fractures. Six fresh-frozen cadaveric spine specimens constituted by five vertebra (T11-L3) and four disks were tested. A specific loading setup has been developed to impose pure moments corresponding to loadings of flexion-extension, lateral bending and axial rotation. Tests were performed on each specimen in an intact state and post kyphoplasty following a burst fracture. Strain measurements and motion variations of spinal unit are measured by a 3D optical method. Strain measurements on vertebral bodies after kyphoplasty shows a great primary stabilisation. Comparisons of mobility and angles variations between the intact and post kyphoplasty states do not highlight significant difference. Percutaneous kyphoplasty offers a good primary stability in case of burst fracture. Kinematics analysis during physiological movements shows that this stabilisation solution preserve disk mobility in each adjacent spinal unit.

Failed back surgery syndrome: what's in a name? A proposal to replace "FBSS" by "POPS" .

BACKGROUND: The current definition of Failed Back Surgery Syndrome (FBSS) has a pejorative and restrictive connotation of blame and failure. Optimally, the evaluation of FBSS patients might be based on a multidimensional approach, involving an array of practitioners including spine surgeons, pain physicians, physiotherapists and behavioural specialists. Even though these clinical interactions should lead to a unique approach, one main problem comes from the fact that FBSS definition has varied over time and remains extremely controversial. There is now a need for global consensus about what we call FBSS, why, when and how. Discussing the name of this syndrome appears to be a logical starting point. DISCUSSION: "PostOperative Persistent Syndrome", summarised by the acronym "POPS", could be an appropriate term to not only encapsulate failure but pain, function and psychosocial dysfunction following unsuccessful spine surgery whether from a technical or expectation standpoint. A return to the source might help to identify the real clinical problem, i.e. the pain mechanism: nociceptive, neuropathic pain or mixed. A clinical and radiological spine assessment is key to ensure that no further surgery is required, by distinguishing within the so-called FBSS population, "true" FBSS patients and "potential" FBSS patients, who are actually not FBSS patients, as an aetiological treatment of potential pain generators still remains possible. CONCLUSION: We propose to replace the FBSS acronym by POPS. The ultimate goal of this redefinition would be to guide the patient towards the future rather than the past and to reach a consensus, based on network discussions, concerning the following items: integrate pain mechanisms into the diagnostic process; implement the notion of a predominant ratio between mechanical/neuropathic pain mechanisms, which defines the potential target for treatment options; create a network supported by a database, to prospectively pool and analyse data, using homogeneous evaluation tools and ultimately define outcome predictors in this population.

Failed back surgery syndrome: who has failed?

INTRODUCTION: Failed back surgery syndrome (FBSS) results from a cascade of medical and surgical events that lead to or leave the patient with chronic back and radicular pain. This concept is extremely difficult to understand, both for the patient and for the therapist. The difficulty is related to the connotations of failure and blame directly associated with this term. The perception of the medical situation varies enormously according to the background and medical education of the clinician who manages this type of patient. Eight health system experts (2 pain physicians, 1 orthopaedic spine surgeon, 1 neuro spine surgeon, 1 functional neurosurgeon, 1 physiatrist, 1 psychologist and one health-economic expert) were asked to define and share their specialist point of view concerning the management of postoperative back and radicular pain. Ideally, it could be proposed that the patient would derive optimal benefit from systematic confrontation of these various points of view in order to propose the best treatment option at a given point in time to achieve the best possible care pathway. CONCLUSION: The initial pejorative connotation of FBSS suggesting failure or blame must now be replaced to direct the patient and therapists towards a temporal concept focusing on the future rather than the past. In addition to the redefinition of an optimised care pathway, a consensus based on consultation would allow redefinition and renaming of this syndrome in order to ensure a more positive approach centered on the patient.

From "mechanical" to "neuropathic" back pain concept in FBSS patients. A systematic review based on factors leading to the chronification of pain (part C).

INTRODUCTION: Beyond initial lesions, any form of spinal (re)operation can cause direct potential aggression to the nervous system by contact with neural tissue or by imprinting a morphological change on the neural tissue. The potential consequences of nerve root injury affect both peripheral and axial dermatomal distribution. The hypothesis of a possible neuropathic aspect associated with the back pain component of failed back surgery syndrome (FBSS) therefore appears to be reasonable. Its pathophysiology remains unclear due to the permanent interplay between nociceptive and neuropathic pain components, resulting in the coexistence of physiological and pathological pain at the same anatomical site. This paper is designed to extensively review the fundamental mechanisms leading to chronification of pain and to suggest considering the emerging concept of "neuropathic back pain". METHODS: Literature searches included an exhaustive review of 643 references and 74 book chapters updated by searching the major electronic databases from 1930 to August 2013. RESULTS: Inflammatory and neuropathic back pain could be distinguished from pure nociceptive pain as a result of an increased activity and responsiveness of sensitized receptors at the peripheral nervous system and also as a consequence of increased afferent inflow to the central nervous system, moving to a new, more excitable "wind-up" state. This can be clinically translated to an amplified response to a moderate/intense stimulus (primary hyperalgesia) or an aversive sensation provoked by the activation of low-threshold mechanoreceptors through non-noxious stimuli, which defines allodynia. Activated non-neuronal cells including microglia have been found to be cellular intermediaries in mechanical allodynia. Major changes in the spinal cord are the loss of inhibitory mechanisms, resulting in an increased activity of interneurons or projection neurons and a structural reorganization of the central projection pattern. This abnormal excitability of sensory neurons is coupled to changes in the neurotransmitter phenotype, which could induce a resistance to conventional analgesic treatments. CONCLUSION: A clear understanding of the factors leading to the chronification of back pain should help us to move to the choice of mechanism related pain treatments to improve outcomes in FBSS chronic condition.

"MAST" prospective study: value of minimal access spine technologies technique for multicolumn spinal cord stimulation surgical lead implantation in the context of a French multicentre randomized controlled trial (ESTIMET study).

BACKGROUND AND PURPOSE: Spinal cord stimulation (SCS) has been demonstrated to be an effective treatment for postoperative persistent leg pain after spine surgery, but treatment of the back pain component remains much more difficult, as it comprises mixed neuropathic and mechanical pain mechanisms. Moreover, these patients could present damaged tissues at the site of SCS lead implantation as a result of previous spine surgery. It can therefore be logically assumed that minimizing the surgical invasiveness of SCS implantation would be beneficial for these patients. Several studies have demonstrated the value of Minimal Access Spine Technologies (MAST) in spine surgery, but only a few case reports have been published concerning the use of MAST techniques for SCS. Therefore, we were prompted to conduct a second ESTIMET ancillary study to prospectively analyse the potential impact and benefits of MAST technique during SCS lead implantation versus an open surgical approach. METHODS: This is a multicentre, comparative, ancillary study conducted in 61 patients among the 115 enrolled patients ESTIMET study. One arm comprises patients undergoing multicolumn lead implantation via a Conventional Open Approach (COA) and the other arm comprises patients implanted by a MAST approach. Patients will be followed for 12 months after lead implantation. The following data will be collected: elevation of muscle enzymes (serum CPK), scar size, blood loss, infection rate, operating time and global, leg, back and scar NPRS. TRIAL STATUS: The first patient of this ancillary study was enrolled on 21 May 2012 and recruitment has now been achieved. Primary endpoint findings are expected to be available in 2015. CONCLUSION: Minimally invasive techniques have now been used for spine surgery for the past 12 years, and could also be useful in the context of SCS lead implantation, especially in patients with chronic back pain prior to implantation.

The Franco-Canadian multicolumn spinal cord stimulation prospective study: a subgroup analysis focusing on the decisive role of lead positioning.

INTRODUCTION: Multicolumn spinal cord stimulation (SCS) is now considered to be effective for the treatment of the radicular and back component in refractory Failed Back Surgery Syndrome (FBSS) patients. The relationship between the paresthesia coverage of the back and clinical outcomes has recently been confirmed by an international prospective study. However, significant disparities in outcomes were identified and could result from the heterogeneity of lead implantation parameters which are dependant on local practices and experience. We therefore sought to analyse the impact of lead implantation level and its lateralization on the ability to address back pain with multicolumn SCS leads. STUDY OBJECTIVES, MATERIALS AND METHODS: The present study was a retrospective subgroup analysis from an observational, prospective non-randomized trial that included 76 patients with refractory FBSS, implanted with multicolumn SCS between 2008 to 2011 in three neurosurgical pain centres (Poitiers, France, Montreal, Canada and Regina, Canada). A subgroup of 21 patients with "optimized lead positioning" (OLP) was identified, distinguished from the rest of the main study population (NON OLP subgroup; n=51) and submitted to specific data analysis. Baseline characteristics of both groups were strictly comparable. Our primary objective was to analyse the impact of lead positioning (vertebral level and lateralization) on the back paresthesia coverage. The secondary objectives were to compare the analgesic and functional efficacy of multicolumn stimulation in these OLP and NON OLP subgroups and to determine if a paresthesia coverage improvement leads to better clinical outcomes in these difficult-to-treat patients. RESULTS: In this subgroup analysis, unilateral coverage of the low back area was achieved in 85.0% of OLP patients vs. 76.5% in the NON OLP group. Bilateral and complete coverage of the low back area was achieved in 60% of OLP patients vs. 51% in the NON OLP group but these differences were not statistically significant. At 6months, 81.0% of OLP patients vs. 69.4% in the NON OLP group presented at least 30% improvement of the low back VAS, while 52.4% of them achieved at least 50% improvement of the low back VAS vs. 38.8% in the NON OLP group. Functional improvement at 6months, available and calculated only in the French group of OLP patients (n=14) by the Oswestry Disability Index, was significant, decreasing from 60.67% to 33.43%. CONCLUSION: Despite limitations in this retrospective subgroup analysis, this study suggests that the vertebral level (T8-T9) and midline positioning of the lead during implantation could be decisive factors to optimize paresthesia coverage and finally, clinical and functional outcomes. While sophistication has been responsible for an increase of the size and the programming possibilities of surgical SCS leads during the past years, multicolumn SCS lead implantation should in fact be considered as a "functional neurosurgical" procedure and could benefit from intraoperative patient cooperation, as in the case for deep brain stimulation procedures, due to minimally invasive implantation techniques.

A prospective study evaluating sleep quality in Failed Back Surgery Syndrome patients treated by multicolumn spinal cord stimulation: study design protocol and presentation of the study population.

BACKGROUND AND PURPOSE: One of the main consequences of chronic pain syndrome is major impairment of the quality of sleep. Chronic pain and insomnia are independently linked to significant reductions in quality of life and psychiatric morbidity. Recent studies have suggested the efficacy of spinal cord stimulation (SCS) for the treatment of the back pain component in failed back surgery syndrome (FBSS) patients using a multicolumn lead. The main aim of this pilot study is to assess the influence and potential benefits of SCS on sleep quality in refractory FBSS patients implanted with multicolumn SCS and enrolled in the French multicentre ESTIMET study. METHODS: This is a single-centre, comparative, exploratory, pilot study. Sixteen FBSS patients enrolled in the ESTIMET study and implanted with multicolumn SCS will be monitored for 6months after implantation. Sleep parameters will be recorded by polysomnography, Psychomotor Vigilance Test and Osler tests, actigraphy, sleepiness scales, and sleep quality testing. Sleep will be evaluated before (at the inclusion visit) and after SCS implantation (at the 6-month visit). Secondary objectives will also assess the impact of SCS lead programming (mono vs. multicolumn SCS) and the influence of position-adaptive stimulation at night on sleep quality. TRIAL STATUS: The first patient of this ancillary study was enrolled on 21 May, 2012 and recruitment has now been achieved. Primary endpoint findings are expected to be available in 2015. CONCLUSION: By providing an analysis of the quality of sleep in chronic pain patients who are candidates for implanted neurostimulation, this new approach focuses on an important aspect of quality of life often overlooked in these poly-medication patients. It could show a real clinical benefit and underestimation of these analgesic innovative expensive techniques, where medico-economic analysis, would or would not promote access.

Neurostimulation options for failed back surgery syndrome: The need for rational and objective measurements. Proposal of an international clinical network using an integrated database and health economic analysis: the PROBACK network.

INTRODUCTION: In the context of failed back surgery syndrome (FBSS) treatment, the current practice in neurostimulation varies from center-to-center and most clinical decisions are based on an individual diagnosis. Neurostimulation evaluation tools and pain relief assessment are of major concern, as they now constitute one of the main biases of clinical trials. Moreover, the proliferation of technological devices, in a fertile and unsatisfied market, fosters and only furthers the confusion. There are three options available to apply scientific debates to our daily neurostimulation practice: intentional ignorance, standardized evidence-based practice or alternative data mining approach. OBJECTIVE: In view of the impossibility of conducting multiple randomized clinical trials comparing various devices, one by one, the proposed concept would be to redefine the indications and the respective roles of the various spinal cord and peripheral nerve stimulation devices with large-scale computational modeling/data mining approach, by conducting a multicenter prospective database registry, supported by a clinician's global network called "PROBACK". METHODS: We chose to specifically analyze 6 parameters: device coverage performance/coverage selectivity/persistence of the long-term electrical response (technical criteria) and comparative mapping of patient pain relief/persistence of the long-term clinical response/safety and complications occurrence (clinical criteria). Two types of analysis will be performed: immediate analysis (including cost analysis) and computational analysis, i.e. demonstration of the robustness of certain correlations of variables, in order to extract response predictors. DISCUSSION/CONCLUSION: By creating an international prospective database, the purpose of the PROBACK project was to set up a process of extraction and comparative analysis of data derived from the selection, implantation and follow-up of FBSS patients candidates for implanted neurostimulation. This evaluation strategy should help to change the opinions of each implanter and each health system towards a more rational decision-making approach subtended by mathematical reality.