Analysis of spinal canal diameter in the placement of thoracic spinal cord stimulator paddle leads.

BACKGROUND: Neurologic deficit is known as a rare complication of thoracic spinal cord stimulator (SCS) paddle lead implantation, but many believe its incidence after SCS paddle lead placement is under-reported. It is possible that imaging characteristics may be used to help predict safe paddle lead placement. OBJECTIVE: This imaging study was undertaken to determine the minimum canal diameter required for safe paddle lead placement. METHODS: Patients who underwent thoracic laminotomy for new SCS paddle lead placement from January 2018 to March 2023 were identified retrospectively. Preoperative thoracic canal diameter was measured in the sagittal plane perpendicular to the disc space from T5/6 to T11/12. These thoracic levels were chosen because they span the most common levels targeted for SCS placement. Patients with and without new neurologic deficits were compared using a Mann-Whitney U-test. RESULTS: Of 185 patients initially identified, 180 had thoracic imaging available for review. One (0.5%) and 2 (1.1%) of 185 patients complained of permanent and transient neurologic deficit after thoracic SCS placement, respectively. Patients with neurologic deficits had average canal diameters of <11 mm. The average canal diameter of patients with and without neurologic deficits was 10.2 mm (range 6.1-12.9 mm) and 13.0 mm (range 5.9-20.2), respectively (p < 0.0001). CONCLUSION: Postoperative neurologic deficit is an uncommon complication after thoracic laminotomy for SCS paddle lead placement. The authors recommend ensuring a starting thoracic canal diameter of at least 12 mm to accommodate a SCS paddle lead measuring 2 mm thick to ensure a final diameter of >10 mm. If canal diameter is <12 mm, aggressive undercutting of the lamina, a second laminotomy, or placement of smaller SCS wire leads should be considered.

Supraorbital Nerve Stimulation for Facial Pain.

PURPOSE OF REVIEW: Chronic facial pain is considered one of the conditions that affect quality of daily life of patients significantly and makes them seek medical help. Intractable facial pain with failed trials of medical treatment and other pain management therapies presents a challenge for neurologists, pain specialists, and neurosurgeons. We describe the possibility of proposing peripheral nerve stimulation of the supraorbital nerves to treat patients with medically intractable facial pain. Stimulation of the supraorbital nerves is performed using percutaneously inserted electrodes that are positioned in the epi-fascial plane, traversing the course of the supraorbital nerves. The procedure has two phases starting with a trial by temporary electrodes that are inserted under fluoroscopic guidance and are anchored to the skin. This trial usually lasts for a few days to 2 weeks. If successful, we proceed to the insertion of a permanent electrode that is tunneled under the skin behind the ear toward the infraclavicular region in which we make a pocket for the implantable pulse generator. RECENT FINDINGS: This procedure has been used in multiple patients with promising results which was published in literature. Literature shows that it provides relief of medically intractable pain, without the need for destructive procedures or more central modulation approaches with a preferable safety profile compared to other invasive procedures. Supraorbital nerve stimulation is now considered a valid modality of treatment for patients with medically intractable facial pain and can be offered as a reliable alternative for the patients while discussing the proper plan of management.

Holistic Treatment Response: An International Expert Panel Definition and Criteria for a New Paradigm in the Assessment of Clinical Outcomes of Spinal Cord Stimulation.

BACKGROUND: Treatment response to spinal cord stimulation (SCS) is focused on the magnitude of effects on pain intensity. However, chronic pain is a multidimensional condition that may affect individuals in different ways and as such it seems reductionist to evaluate treatment response based solely on a unidimensional measure such as pain intensity. AIM: The aim of this article is to add to a framework started by IMMPACT for assessing the wider health impact of treatment with SCS for people with chronic pain, a "holistic treatment response". DISCUSSION: Several aspects need consideration in the assessment of a holistic treatment response. SCS device data and how it relates to patient outcomes, is essential to improve the understanding of the different types of SCS, improve patient selection, long-term clinical outcomes, and reproducibility of findings. The outcomes to include in the evaluation of a holistic treatment response need to consider clinical relevance for patients and clinicians. Assessment of the holistic response combines two key concepts of patient assessment: (1) patients level of baseline (pre-treatment) unmet need across a range of health domains; (2) demonstration of patient-relevant improvements in these health domains with treatment. The minimal clinical important difference (MCID) is an established approach to reflect changes after a clinical intervention that are meaningful for the patient and can be used to identify treatment response to each individual domain. A holistic treatment response needs to account for MCIDs in all domains of importance for which the patient presents dysfunctional scores pre-treatment. The number of domains included in a holistic treatment response may vary and should be considered on an individual basis. Physiologic confirmation of therapy delivery and utilisation should be included as part of the evaluation of a holistic treatment response and is essential to advance the field of SCS and increase transparency and reproducibility of the findings.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations on Best Practices for Cervical Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on the use of neurostimulation in the cervical region to improve outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for an often-overlooked area of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based upon their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to the present. Identified studies were graded using the US Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant. RESULTS: The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The NACC recommends best practices regarding the use of cervical neuromodulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be utilized as a guide to assist decision making when clinically appropriate.

Microscale Physiological Events on the Human Cortical Surface.

Despite ongoing advances in our understanding of local single-cellular and network-level activity of neuronal populations in the human brain, extraordinarily little is known about their "intermediate" microscale local circuit dynamics. Here, we utilized ultra-high-density microelectrode arrays and a rare opportunity to perform intracranial recordings across multiple cortical areas in human participants to discover three distinct classes of cortical activity that are not locked to ongoing natural brain rhythmic activity. The first included fast waveforms similar to extracellular single-unit activity. The other two types were discrete events with slower waveform dynamics and were found preferentially in upper cortical layers. These second and third types were also observed in rodents, nonhuman primates, and semi-chronic recordings from humans via laminar and Utah array microelectrodes. The rates of all three events were selectively modulated by auditory and electrical stimuli, pharmacological manipulation, and cold saline application and had small causal co-occurrences. These results suggest that the proper combination of high-resolution microelectrodes and analytic techniques can capture neuronal dynamics that lay between somatic action potentials and aggregate population activity. Understanding intermediate microscale dynamics in relation to single-cell and network dynamics may reveal important details about activity in the full cortical circuit.

Motor Cortex Stimulation for Facial Pain.

Motor cortex stimulation (MCS) has been used in the treatment of intractable neuropathic facial pain for nearly 30 years. While efficacy rates have been noted as high as 88% in some studies, considerable variability in treatment response remains. Additionally, MCS is often cited as providing diminishing relief over time, and there are few long-term studies on efficacy. Complications are generally mild and include infection, hardware complication, seizure, and transient neurological deficit. Despite relatively minimal use, MCS remains a viable treatment option for the appropriately selected facial pain patients that have proved refractory to conservative management.

Assisted movement with proprioceptive stimulation reduces impairment and restores function in incomplete spinal cord injury.

OBJECTIVE: To test whether treatment with assisted movement with enhanced sensation (AMES) using vibration to the antagonist muscle would reduce impairments and restore upper limb function in people with incomplete tetraplegia. DESIGN: Prospective, pre-post study. SETTING: Laboratory and rehabilitation hospital. PARTICIPANTS: We recruited 15 arms from 10 individuals (8 men; mean age, 40.5 y; mean years postspinal cord injury [SCI], 3) with chronic, incomplete tetraplegia. INTERVENTION: Two or three 20-minute sessions per week over 9 to 13 weeks (25 sessions total) on the AMES device, which combines repeated movement with targeted vibration to the antagonist muscle. MAIN OUTCOME MEASURES: Strength and active motion tests on the AMES device; International Standards for the Neurological Classification of SCI (ISNCSCI) motor and sensory examinations; Modified Ashworth Scale (MAS); grasp and release test (GRT); Van Lieshout Test (VLT); and Capabilities of Upper Extremity questionnaire (CUE). RESULTS: The AMES strength test scores improved significantly in metacarpophalangeal flexion (P=.024) and extension (P=.007) and wrist flexion (P=.001) and extension (P<.000). The AMES active motion scores improved in the hand (P=.001) and wrist (P=.001). The MAS and ISNCSCI scores remained unchanged, whereas the GRT scores increased (P=.025). Post hoc analysis showed a trend from pre- to posttreatment (P=.068) and a significant change from pretreatment to 3-month follow-up (P=.046). There was no significant change in the VLT (P=.951) or the CUE (P=.164). Five of the 10 participants reported a return of sensation to the digits after the first, second, or third treatment session. CONCLUSIONS: People with chronic, incomplete tetraplegia may experience improvements in impairments and function after treatment on a device combining assisted movement and proprioceptive stimulation. Further investigation is warranted.

Lesioning and stimulation in tremor-predominant movement disorder patients: an institutional case series and patient-reported outcome.

BACKGROUND: In certain movement disorder cases, a combined stimulation and lesioning approach in the same patient could be the ideal beneficial option. OBJECTIVES: The object of this study was to retrospectively examine the indications, outcome and complications in patients who had undergone both a lesioning (thalamotomy) and deep brain stimulation (DBS) procedure (bilateral or unilateral) for a tremor-predominant movement disorder performed by a single surgeon at one institution over a 15-year period. METHODS: A retrospective review of patient records was undertaken. Patient outcome was based on follow-up visit chart notes and on a non-validated patient telephone questionnaire. RESULTS: Thirty patients required a combined stimulation and lesioning approach to control tremor. Twelve patients had either unilateral or bilateral DBS as the first procedure followed by thalamotomy; two patients required a third procedure. Eighteen patients had thalamotomy as the first procedure followed by contralateral DBS either as the second or the third procedure. Eight patients required three procedures, which included either a repeat thalamotomy or a repeat DBS. We were able to contact 22 of 30 (15 male and 15 female, average age 70.7 ± 15.4 years) tremor-predominant movement disorder patients, retrospectively. Patient-reported outcome as assessed by a non-validated telephone questionnaire was: improvement in both symptoms and function in 59%, symptom but not function improvement in 32% and no improvement in either symptom or function or worsening in 9%. In comparison, based on retrospective chart review, 77% of patients had improved symptoms and functions, 20% of patients had improved symptoms with no effect on function and 3% of patients had no improvements of symptoms or functions. CONCLUSIONS: Lesioning, which has to a great extent fallen out of favor, still has a valuable role to play in the treatment of tremor-predominant movement disorders; it can still be applied in combination with stimulation with outcome results similar to that of bilateral stimulation.

Motor cortex stimulation for trigeminal neuropathic or deafferentation pain: an institutional case series experience.

BACKGROUND: Trigeminal neuropathy is a rare, devastating condition that can be intractable and resistant to treatment. When medical treatment fails, invasive options are limited. Motor cortex stimulation (MCS) is a relatively recent technique introduced to treat central neuropathic pain. The use of MCS to treat trigeminal neuropathic or deafferentation pain is not widespread and clinical data in the medical literature that demonstrate efficacy are limited. METHOD: We retrospectively reviewed patients with trigeminal neuropathic or trigeminal deafferentation pain who were treated at the Oregon Health & Science University between 2001 and 2008 by 1 neurosurgeon using MCS. RESULTS: Eight of 11 patients (3 male, 8 female) underwent successful permanent implantation of an MCS system. All 8 patients reported initial satisfactory pain control. Three failed to experience continued pain control (6 months of follow-up). Five continued to experience long-term pain control (mean follow-up, 33 months). Average programming sessions were 2.2/year (all 8 patients) and 1.55/year (5 patients who sustained long-term pain control). Patients with anesthesia dolorosa or trigeminal deafferentation pain who had previously undergone ablative trigeminal procedures responded poorly to MCS. We encountered no perioperative complications. CONCLUSION: MCS is a safe and potentially effective therapy in certain patients with trigeminal neuropathy.