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.

INTRODUCTION: 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. METHODS: We conducted a prospective, nonrandomized, observational study on 76 patients with refractory FBSS, consecutively implanted with multicolumn spinal cord stimulation (SCS) between 2008 and 2011 in three neurosurgical pain management centers (Poitiers, France; Montréal, Canada; and Regina, Canada). The primary objective of this study was to prospectively analyze the effect of multicolumn lead programming on paresthesia coverage for the back pain region in these patients. The secondary objective was to assess the analgesic efficacy of this technique on the global and back pain components. RESULTS: Paresthesia could be induced in the lower extremities in the majority of patients with at least one of the configurations tested. Bilateral low back paresthesia was induced in 53.5% of patients, while unilateral low back paresthesia was induced in 78.9% of patients. Multicolumn configurations were statistically more effective than monocolumn configurations for all anatomic regions studied. At 6 months, 75.4% of patients receiving multicolumn stimulation (n = 57) obtained at least a 30% improvement of the back pain VAS score, while 42.1% of patients obtained at least a 50% improvement of the back pain VAS score. CONCLUSION: This study confirms the hypothesis that multicolumn SCS should be considered as an important tool in the treatment of radicular and axial pain in FBSS patients. The efficacy of this modality is based on a rigorous patient selection process, access to new generation lead technologies, but most importantly an algorithmic programming approach for optimal stimulation and electrical field shaping. With over 40 million potential programming combinations associated with 16 contact leads to achieve paresthesia coverage, optimal stimulation is often missed as either the patient or the clinician become exhausted or overwhelmed during the course of therapy programming and optimization session.

Should we recommend occipital plate fixation using bicortical screws or inverted occipital hooks to optimize occipito-cervical junction fusion? A biomechanical study combining an experimental and analytical approach.

BACKGROUND: Occipito-cervical fusion can be necessary in case of cranio-cervical junction instability. Proximal stabilisation is usually ensured by bi-cortical occipital screws implanted through one median or two lateral occipital plate(s). Bone thickness variability as well as the proximity of vasculo-nervous elements can induce substantial morbidity. The choice of site and implant type remains difficult for surgeons and is often empirically based. Given this challenge, implants with smaller pitch to increase bone interfacing are being developed, as is a surgical technique consisting in inverted occipital hook clamps, a potential alternative to plate/screws association. We present here a biomechanical comparison of the different occipito-cervical fusion devices. METHODS: We have developed a 3D mark tracking technique to measure experimental mechanical data on implants and occipital bone. Biomechanical tests were performed to study the mechanical stiffness of the occipito-cervical instrumentation on human skulls. Four occipital implant systems were analysed: lateral plates+large pitch screws, lateral plates+hooks, lateral plates+small pitch screws and median plate+small pitch screws. Mechanical responses were analysed using 3D displacement field measurements from optical methods and compared with an analytical model. FINDINGS: Paradoxical mechanical responses were observed among the four types of fixations. Lateral plates+small pitch screws appear to show the best accordance of displacement field between bone/implant/system interface providing higher stiffness and an average maximum moment around 50 N.m before fracture. INTERPRETATION: Stability of occipito-cervical fixation depends not only on the site of screws implantation and occipital bone thickness but is also directly influenced by the type of occipital implant.

Multicolumn spinal cord stimulation lead implantation using an optic transligamentar minimally invasive technique.

BACKGROUND: A new generation of neurostimulation surgical leads is used to increase the success of spinal cord stimulation in difficult-to-treat indications such as failed back surgery syndrome. Minimal access spinal technologies (MASTs) have previously been used for surgical lead implantation. However, only a unilateral approach was possible, causing difficulties for median lead placement, and not always preventing laminectomy. A recent MAST technique was used to implant spinal cord stimulation leads without these limitations. OBJECTIVE: To describe the MAST technique used in a pilot study. METHODS: Twenty-four consecutive patients were implanted with a multicolumn surgical lead for refractory chronic back and leg pain by using the optic transligamentar MAST technique. RESULTS: The MAST technique allowed median lead placement, facilitated visualization of the spine, and permitted transligamentar insertion that minimized scarring and muscle damage. No technique-related adverse events or lead revisions were reported. CONCLUSION: Use of a MAST approach could be useful in safe implantation of multicolumn surgical leads in difficult-to-treat, refractory lower back pain conditions such as failed back surgery syndrome.

Back pain: a real target for spinal cord stimulation?

BACKGROUND: Failed back surgery syndrome represents one of the most frequent etiologies of chronic back pain and is a major public health issue. Neurostimulation has currently not been validated in the treatment of back pain because of technological limitations in implantable spinal cord stimulation (SCS) systems. New-generation leads using several columns of stimulation can generate longitudinal and/or transverse stimulation fields into the spinal cord. OBJECTIVE: To investigate, through extensive stimulation testing, the capacity of multicolumn tripolar leads to achieve back territory paresthesia coverage in refractory failed back surgery syndrome patients. METHODS: Eleven patients implanted with a 16-contact spinal cord stimulation lead (Specify 5-6-5, Medtronic Inc) were assessed with a systematic exploration of 43 selected stimulation configurations to generate bilateral back paresthesia in addition to leg territory coverage. RESULTS: The tripolar lead successfully generated paresthesia in both bilateral back and leg territories in 9 patients (81.8%). Success rates of multicolumn stimulation patterns were significantly higher than for longitudinal configurations for lombodorsal paresthesia coverage. Six months after implantation, significant pain relief was obtained compared with preoperative evaluation for global pain (Visual Analog Scale, 2.25 vs 8.2 preoperatively; P < .05), leg pain (Visual Analog Scale, 0.5 vs 7.6 preoperatively; P < .05), and back pain (Visual Analog Scale, 1.5 vs 7.8 preoperatively; P < .05). CONCLUSION: These results suggest that multicolumn leads can reliably generate back pain coverage and favor pain relief outcomes. This may lead physicians to reconsider new indications for spinal cord stimulation. Expanding neurostimulation perspectives to intractable back pain syndromes could become realistic in the near future.

Successful treatment of pudendal neuralgia with tricolumn spinal cord stimulation: case report.

BACKGROUND AND IMPORTANCE: There is large variation in the success of decompressive surgery for pudendal neuralgia (PN), the most chronic, disabling form of perineal pain. We attempt to determine whether spinal cord stimulation using new-generation multicolumn leads could form part of the treatment algorithm for refractory PN. CLINICAL PRESENTATION: A man with PN that was unresponsive to conventional treatment demonstrated a neuropathic component and had a negative response to nerve infiltrations (so he was not indicated for decompressive surgery) and a positive response to perianal transcutaneous electrical nerve stimulation and was implanted with a 16-contact surgical lead at the level of conus medullaris, allowing multicolumn stimulation. Using transverse combinations, it was possible to obtain 100% paresthesia over the perineal area without unwanted dorsal root stimulation. Perineal and radicular pain was successfully relieved for up to 12 months (80% and 60% reduction in the visual analogue scale scores, respectively), with an improvement in all quality of life domains and a reduction in drug consumption. CONCLUSION: Spinal cord stimulation using a 16-contact lead may be a viable therapeutic option for patients with refractory PN for whom decompressive surgery is contraindicated.