Multicolumn spinal cord stimulation for significant low back pain in failed back surgery syndrome: design of a national, multicentre, randomized, controlled health economics trial (ESTIMET Study).

BACKGROUND: Many studies have demonstrated the efficacy of spinal cord stimulation (SCS) for chronic neuropathic radicular pain over recent decades, but despite global favourable 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. The 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. Évaluation médico-économique de la STImulation MEdullaire mulTi-colonnes (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. MATERIALS AND METHODS: FBSS patients with a radicular pain VAS score≥50mm, associated with a significant back pain component were recruited in 14 centres 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 12months 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. TRIAL STATUS: Trial recruitment started in May 2012. As of September 2013, all 14 study centres have been initiated and 112/115 patients have been enrolled. Preliminary results are expected to be published in 2015. TRIAL REGISTRATION: Clinical trial registration information-URL: www.clinicaltrials.gov. Unique identifier NCT01628237.

An unusual cause of foot clonus: spasticity of fibularis longus muscle.

The functional consequences of spasticity can be corrected by local, pharmacological or surgical treatments once the spastic muscle has been identified. However, this diagnosis can be tricky when the muscle in question is rarely involved in spasticity or when its mechanical action is unusual or poorly characterized. Here, we present the case of a man presenting with left hemiplegia after an ischaemic stroke. His gait was perturbed by foot clonus in the sagittal plan, which persisted after selective neurotomy of the gastrocnemius and soleus but disappeared after neurotomy of the peroneus longus. Clonus triggered by pushing up under the whole of the forefoot in the direction of dorsiflexion may not be related to spasticity of the triceps surae. We recommend screening for foot clonus by first pushing up on the sole of the foot under all five metatarsals. In a second step, selectively pushing up under the first metatarsal joint enables the physician to evidence spasticity of the peroneus longus.

[Neurostimulation procedures in refractory pain]. / Techniques de neurostimulation et douleurs réfractaires.

In the context of chronic pain, the technics of neuromodulation have a significative place especially when they are neuropathic with a precise selection of the indications according to the neurophysiological, anatomical and clinical data. The choice is essentially based upon the severity and the site of pain. They are totally conservative, adaptable and reversible but it is necessary to organize a very rigorous clinical and technical follow-up according to a multidisciplinary approach.

Anatomical bases of tibial neurotomy for treatment of spastic foot.

Spastic pes equines, possibly associated with varus posture or spastic claw of the toes, can require neurosurgical treatment. In these cases, a selective fascicular neurotomy can be proposed, which consists of a partial section of some motor collateral branches of the tibial nerve. In order to avoid sensory and trophic complications after surgery due to an excessive manipulation of the nerve, accurate anatomical data must be collected. Therefore, biometric, histological and ultrastructural studies were carried out. A total of 50 dorsal compartments of the leg were dissected. The distance between the emergence of each muscular branch of the tibial nerve and anatomical landmarks were measured. Complementary histological study was processed on three specimens with slices stained by Masson's trichromatic method. Eventually, electronic microscopy observation was processed on two other specimens. In 16 cases (32%), we found a common muscular branch for all the muscles of the dorsal leg compartment, which emerged from the nerve trunk near the tendinous arch of the soleus (67 +/- 29 mm from the femorotibial articular line). In the other cases, muscular branches of the nerve emerged from its ventral lateral aspect, with variable origins (inferior nerve for the soleus: 82 +/- 31 mm from the femorotibial articular line, nerve for flexor digitorum longus: 116 +/- 41 mm, nerve for tibialis posterior: 106 +/- 51 mm, with a second nerve in 9/50 cases, nerve for flexor hallucis longus: 129 +/- 48 mm, with a second nerve in 6 cases). Histological and ultrastructural analysis confirmed the presence of the motor nervous fibers in the ventral lateral part of the nerve trunk. These new anatomical findings allow a more precise dissection during operative procedure, in order to avoid sensory or trophic complications.

Comparison of botulinum toxin injection and neurotomy in patients with distal lower limb spasticity.

BACKGROUND AND PURPOSE: We compared the efficacy of botulinum toxin injection (BTI) and tibial nerve neurotomy (TNN) in an open-label study of 34 post-stroke hemiplegic patients with distal lower limb deformation. METHODS: The dose of BT was 300 U (Botox). TNN was performed with a 6-12 month delay on the motor branches of the tibial nerve. Muscles to be treated were selected according to the distal deformity (equinus, varus and clawing toes). Patients were assessed following each treatment for spasticity, motor control, range of movements, balance, gait and the Rivermead Motor Assessment. RESULTS: TNN (M3, M6 and Y1) resulted in a more significant effect than BTI (D15, M2 and M5) on most of the measures: ankle plantar flexor spasticity, range of movement in dorsiflexion and eversion, foot position in upright situation, Functional Ambulation Categories (barefoot), RMA, gait velocity (comfortable condition), subjective benefit and use of walking aids. Patients treated for tibialis posterior or flexor digitorum longus spasticity often complained of subjective sensory disorders at the plantar sole over a period of 4-6 weeks. CONCLUSION: In conclusion, TNN is more effective than BTI on most of the functional parameters. The interest of BTI lies in the preliminary testing of the efficacy of a technique for reducing spasticity on lower limb function.

[Cost-benefit evaluation of spinal cord stimulation treatment for failed-back surgery syndrome patients]. / Evaluation coût/bénéfice du traitement des lombosciatalgies post-operatoires par stimulation médullaire.

BACKGROUND AND PURPOSE: Spinal cord stimulation is a well-known treatment of rigorously selected failed-back surgery syndrome patients. Efficacy levels over 50% of pain relief have been reported in long-term studies. The objective of this multicenter prospective evaluation was to analyze the cost to benefit ratio of spinal cord stimulation treatment for failed back surgery syndrome patients. METHODS: Nine hospitals (pain evaluation and treatment centers) were involved in the study. Forty-three patients were selected and implanted between January 1999 and January 2000. For each patient, pre- and post-operative evaluations (6, 12 and 24 months after implantation) were performed to assess pain relief and economical impact on pain treatment costs. RESULTS: After 24 months, mean 60% pain relief was achieved as assessed with the neuropathic pain score using a Visual Analog Scale (success rate=70%), whereas low-back pain was moderately reduced (29%). The Oswestry Disability questionnaire score was improved by a mean 39%. Costs of pain treatment (medication, consultation, other) are reduced by a mean 64% (1705 Euro) per patient per year. CONCLUSIONS: This study confirms a clear analgesic effect on neuropathic sciatalgia, and moderate attenuation of low-back pain. One particular interest of this study is the medico-economic prospective evaluation showing that the initial cost of the implanted device is compensated by a significant, early, and stable reduction in the cost of associated pain therapies.

[Neurostimulation in the treatment of chronic pain]. / Les techniques de neurostimulation dans le traitement de la douleur chronique.

Different types of neurostimulation are proposed essentially in cases of chronic neuropathic pain, non controlled by anticonvulsivants and antidepressants. The aim is usually to activate a failing inhibitory system, involved in the transmission and the modulation of the nociceptive stimulus. The site of stimulation (transcutaneous, spinal cord, thalamic) is choosen according to the severity of pain and especially the degree of lemniscal dysfunction evaluated by clinical and electrophysiological data. Transcutaneous electrical stimulation and spinal cord stimulation are efficient for neurogenic pain secondary to partial deafferentation. When dysfunction or lesion extend to the pre-ganglionic portion, it's preferable to propose stereotactic thalamic stimulation or central gyrus stimulation. The analgesic effect concerns permanent burning pain in the context of sensitive deafferentation: after distal nervous lesions, radicular, plexular or spinal lesions or after stroke with ischemic lesions along the nociceptive pathways. These different methods must only be proposed if there is a frequent clinical and technical monitoring.