Safety, Efficacy, and Durability of Outcomes: Results from SECURE: A Single Arm, Multicenter, Prospective, Clinical Study on a Minimally Invasive Posterior Sacroiliac Fusion Allograft Implant.

Introduction: Research suggests that sacroiliac joint (SIJ) dysfunction is responsible for 15% to 30% of reported low back pain cases. Recently, there has been an increasing interest in SIJ fusion using minimally invasive surgery (MIS) due to safety. Initially, devices designed for MIS were intended for lateral approaches. A minimally invasive sacroiliac fusion implant for use with a posterior approach has been developed and is regulated for clinical use under the regulatory framework required for human cells, tissues, or cellular or tissue-based products (HCT/Ps). Methods: A multi-center, prospective, single-arm study was launched after initial studies provided preliminary data to support safety, efficacy, and durability of this minimally invasive sacroiliac posterior fusion LinQ allograft implant (NCT04423120). Preliminary results were reported previously. Final results for the full participant cohort are presented here. Results: One-hundred and fifty-nine (159) participants were enrolled across 16 investigational sites in the US between January 2020 and March 2022. One-hundred and twenty-two (122) participants were implanted. At the 1-month follow-up, 82 participants satisfied all criteria for the composite responder endpoint, representing 73.2% of the study cohort. These results stayed consistent across the remaining study timepoints with 66.0%, 74.4%, and 73.5% of participants classified as responders at the 3-, 6- and 12-month follow-up visits, respectively. VAS scores were significantly reduced (p < 0.0001) and ODI scores were significantly improved (p < 0.0001). All domains of the PROMIS-29 were also significantly improved (all p's <0.0001). Only one procedure-related serious AE was reported in the study. Conclusion: These results suggest that the posterior approach LinQ Implant System is a safe and effective treatment for sacroiliac joint dysfunction at 12 months, with results that are favorable compared to outcomes reported for an FDA-cleared lateral approach.

Objective wearable measures correlate with self-reported chronic pain levels in people with spinal cord stimulation systems.

Spinal Cord Stimulation (SCS) is a well-established therapy for treating chronic pain. However, perceived treatment response to SCS therapy may vary among people with chronic pain due to diverse needs and backgrounds. Patient Reported Outcomes (PROs) from standard survey questions do not provide the full picture of what has happened to a patient since their last visit, and digital PROs require patients to visit an app or otherwise regularly engage with software. This study aims to assess the feasibility of using digital biomarkers collected from wearables during SCS treatment to predict pain and PRO outcomes. Twenty participants with chronic pain were recruited and implanted with SCS. During the six months of the study, activity and physiological metrics were collected and data from 15 participants was used to develop a machine learning pipeline to objectively predict pain levels and categories of PRO measures. The model reached an accuracy of 0.768 ± 0.012 in predicting the pain intensity of mild, moderate, and severe. Feature importance analysis showed that digital biomarkers from the smartwatch such as heart rate, heart rate variability, step count, and stand time can contribute to modeling different aspects of pain. The results of the study suggest that wearable biomarkers can be used to predict therapy outcomes in people with chronic pain, enabling continuous, real-time monitoring of patients during the use of implanted therapies.

Minimally Invasive Postero-Inferior Sacroiliac Joint Fusion: Surgical Technique and Procedural Details.

(1) Background: Minimally invasive sacroiliac joint (SIJ) fusion is the preferred surgical intervention to treat chronically severe pain associated with SIJ degeneration and dysfunction. (2) Methods: This paper details the ten-step surgical procedure associated with the postero-inferior approach using the PsiF™ DNA Sacroiliac Joint Fusion System. (3) Results: The posterior surgical approach with an inferior operative trajectory (postero-inferior) utilizes easily identifiable landmarks to provide the safest, most direct access to the articular joint space for transfixing device placement. Implanting the device through the subchondral bone provides maximum fixation and stabilization of the joint by utilizing an optimal amount of cortical bone-implant interface. Approaching the joint from the inferior trajectory also places the implant perpendicular to the S1 endplate at a "pivot point" near the sacral axis of rotation, which addresses the most significant motion of the joint. (4) Conclusions: Further observational data from real-world clinical use are encouraged to further validate this procedure as the surgical preference for minimally invasive SIJ fusion.

Objective wearable measures and subjective questionnaires for predicting response to neurostimulation in people with chronic pain.

BACKGROUND: Neurostimulation is an effective therapy for treating and management of refractory chronic pain. However, the complex nature of pain and infrequent in-clinic visits, determining subject's long-term response to the therapy remains difficult. Frequent measurement of pain in this population can help with early diagnosis, disease progression monitoring, and evaluating long-term therapeutic efficacy. This paper compares the utilization of the common subjective patient-reported outcomes with objective measures captured through a wearable device for predicting the response to neurostimulation therapy. METHOD: Data is from the ongoing international prospective post-market REALITY clinical study, which collects long-term patient-reported outcomes from 557 subjects implanted by Spinal Cord Stimulator (SCS) or Dorsal Root Ganglia (DRG) neurostimulators. The REALITY sub-study was designed for collecting additional wearables data on a subset of 20 participants implanted with SCS devices for up to six months post implantation. We first implemented a combination of dimensionality reduction algorithms and correlation analyses to explore the mathematical relationships between objective wearable data and subjective patient-reported outcomes. We then developed machine learning models to predict therapy outcome based on the subject's response to the numerical rating scale (NRS) or patient global impression of change (PGIC). RESULTS: Principal component analysis showed that psychological aspects of pain were associated with heart rate variability, while movement-related measures were strongly associated with patient-reported outcomes related to physical function and social role participation. Our machine learning models using objective wearable data predicted PGIC and NRS outcomes with high accuracy without subjective data. The prediction accuracy was higher for PGIC compared with the NRS using subjective-only measures primarily driven by the patient satisfaction feature. Similarly, the PGIC questions reflect an overall change since the study onset and could be a better predictor of long-term neurostimulation therapy outcome. CONCLUSIONS: The significance of this study is to introduce a novel use of wearable data collected from a subset of patients to capture multi-dimensional aspects of pain and compare the prediction power with the subjective data from a larger data set. The discovery of pain digital biomarkers could result in a better understanding of the patient's response to therapy and their general well-being.

Six Month Interim Outcomes from SECURE: A Single arm, Multicenter, Prospective, Clinical Study on a Novel Minimally Invasive Posterior Sacroiliac Fusion Device.

INTRODUCTION: Sacroiliac joint disease is a prominent diagnosis across the world. A novel fixation technique employing a posterior approach, single point, bone allograft transfixation has proven to be helpful anecdotally. The purpose of this is study is to investigate prospectively the safety and efficacy of this approach. METHODS: A multicenter, prospective, single arm study was performed after patient identification and treatment with the novel posterior fusion, single-point transfixation system and followed for 24 months. Target enrollment is 100 patients. Interim results on the first 69 consecutive patients at 6 months is presented. Primary endpoint at 6-month analysis was Pain Intensity reduction by visual analogue scale and functional improvement by Oswestry Disability Index. Adverse events were assessed for safety analysis. RESULTS: In total, 69 patients were identified for this analysis. At 6 months, a mean improvement of 34.9 was identified by a reduction in VAS and functional improvement was demonstrated by a mean reduction in ODI of 17.7. There were three adverse events, all unrelated to the device. CONCLUSION: The posterior single point transfixation is safe and efficacious for the treatment of sacroiliac joint dysfunction with statistical improvements in pain and function.

Serial ganglion impar blocks in a patient with nutcracker syndrome refractory to left renal vein transposition: a case report.

BACKGROUND: Nutcracker syndrome is a rare disorder caused by compression of the left renal vein, usually between the aorta and the superior mesenteric artery. It typically presents with left-sided abdominal pain and hematuria. Left renal vein transposition is the most commonly employed surgical technique to alleviate the compression. CASE PRESENTATION: A 22-year-old Caucasian man with a known diagnosis of nutcracker syndrome had undergone left renal vein transposition 1 year before presentation without any subsequent pain relief. In addition, his surgery was complicated by massive blood loss and a 1-week-long stay in an intensive care unit (ICU); as such, he was not amenable to further surgical intervention or stenting to treat his underlying pathology. His symptoms included constant sharp left-sided flank, perineal, and testicular pain. A series of ganglion impar blocks were performed every 3-4 months over the course of 5 years with substantial pain relief achieved. CONCLUSIONS: Our case report highlights a treatment option that has not yet been described for patients with pain secondary to nutcracker syndrome refractory to surgical intervention.

Single S1 Dorsal Root Ganglia Stimulation for Intractable Complex Regional Pain Syndrome Foot Pain After Lumbar Spine Surgery: A Case Series.

INTRODUCTION: Intractable complex regional pain syndrome (CRPS)-related chronic foot pain, is a common therapeutic challenge for interventional pain management physicians and patients alike. Dorsal root ganglia (DRG) stimulation is a very target specific dorsal column stimulation technique with very promising clinical outcomes. Patients with CRPS foot pain and previous back surgery can benefit from DRG stimulation but also run a significant risk of epidural trauma from the DRG sheath advancement. Most sensory innervation to the foot is from L5 and S1 dermatomes. Although there is dual modulation from L5 and S1 DRG, significant "cross talk" exists between these structures such that a DRG lead solely at S1 could provide pain relief for the entire foot. In this case series, we examined the outcomes obtained from placement of solely S1 DRG stimulating electrodes in patients with CRPS-related chronic foot pain, and examine whether this may provide a reduced risk of dural injury. Furthermore, we describe the technical aspects of a S1 DRG placement and discuss relevant anatomical issues pertaining to this approach. MATERIALS AND METHODS: Five patients (four female, one male) with chronic foot pain participated. The oldest was 71 and the youngest 49. Three patients were diagnosed with foot CRPS-1, and two patients with foot CRPS-2. All patients had back surgery in the past and all underwent a trial and subsequent S1 DRG implantation. The patients were evaluated with a numeric rating score (NRS) for pain and function before the procedure and one, two, three, and six months after the procedure. The first patient underwent an L5 and S1 trial and developed CSF leak and postdural puncture headache. Two months later, the patient was re-trialed and implanted with a single S1 electrode. The other four patients were trialed and implanted with single S1 DRG electrodes. RESULTS: All five patients had severe pain (8-10 NRS) and significant loss of function and quality of life (2-4 NRS) before the procedure. All five patients had excellent (0-3 NRS) pain relief and functional restoration (8-10 NRS) with a single S1 electrode trial, and all five proceeded with permanent implantation. The pain relief from the S1 DRG stimulation extended to the entire foot without any sparing. All patients were able to discontinue or significantly reduce their oral pain medications. The one-, two-, three-, and six-month follow-up showed preservation of therapeutic efficacy. CONCLUSIONS: A single S1 DRG electrode placement in patients diagnosed with CRPS of the foot and who had previous back surgery is therapeutically effective and can minimize the risk of dural trauma and CSF leak.

The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation.

INTRODUCTION: The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes. METHODS: The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations. RESULTS: The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation. CONCLUSION: The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.

Multicenter Retrospective Study of Neurostimulation With Exit of Therapy by Explant.

INTRODUCTION: Spinal cord stimulation (SCS) devices are cost effective and improve function as well as quality of life. Despite the demonstrated benefits of SCS, some patients have the device explanted. We are interested in exploring the patient characteristics of those explanted. METHODS: This is a retrospective chart review of neurostimulation patients who underwent explantation at 18 centers across the United States within the previous five years. RESULTS: Data from 352 patients were collected and compiled. Failed Back Surgery syndrome was the most common diagnosis (38.9%; n = 136/350) and over half of the patients reported numerical rating scale (NRS) scores ≥8 prior to implant (64.3%; n = 207/322). All patients reported changes in NRS scores across time, with an initial decrease after implant followed by a pre-explant increase (F (2, 961) = 121.7, p < 0.001). The most common reason for device explant was lack or loss of efficacy (43.9%; 152/346) followed by complications (20.2%; 70/346). Eighteen percent (18%; 62/343) of patients were explanted by a different physician than the implanting one. Rechargeable devices were explanted at a median of 15 months, whereas primary cell device explants occurred at a median of 36 months (CI 01.434, 2.373; median endpoint time ratio = 2.40). DISCUSSION: Loss or lack of efficacy and complications with therapy represent the most frequent reasons for neurostimulation explantation. Of the devices that were explanted, therapy was terminated earlier when devices were rechargeable, when complications occurred, or when pain relief was not achieved or maintained. Furthermore, in nearly 20% of the cases, a different provider than the implanting physician performed device removal. CONCLUSIONS: SCS is largely a safe and efficacious strategy for treating select chronic refractory pain syndromes. Further prospective data and innovation are needed to improve patient selection, maintain SCS therapeutic efficacy and reduce the reasons that lead to device explant.

Results From the Partnership for Advancement in Neuromodulation Registry: A 24-Month Follow-Up.

OBJECTIVE: This longitudinal, clinical outcome study was a multicenter, prospective, observational, registry with a 24-month assessment of patients implanted with spinal cord stimulation (SCS) systems for the management of chronic pain of the trunk and/or limbs. METHODS: On informed consent and institutional review board approval, 614 patients from 39 sites were enrolled within 30 days following permanent SCS system implantation. Medication usage, patient-reported pain relief (PRP), categorical ratings of pain relief, pain disability index scores (PDI), quality of life (QoL), and patient satisfaction were assessed at enrollment, 3-, 6-, 12-, 18-, and 24-month postimplant. Device-related adverse events (AEs) were recorded and reported. RESULTS: Across all visits, statistically significant improvements were reported on all outcome measures. Mean PRP was 58.5% (± 26.4) at 3 months, 56.8% (± 29.2) at 6 months, 57.7% (± 28.9) at 12 months, 55.6% (± 29.8) at 18 months, and 56.3% (± 30.3) at 24 months. More than 65% of patients at any visit reported a PRP ≥ 50%. Mean PDI scores reduced from 46.9 points at baseline to 32.7, 31.8, 31.5, 32.1, 32.1 points at 3, 6, 12, 18, and 24 months (p ≤ 0.0001), respectively. Greater than 76% of patients at any visit were satisfied with their therapy. The majority of patients categorized pain relief as excellent or good on a 5-item scale and reported overall QoL as greatly improved or improved on a 5-item scale. An average of 88% of patients stopped, decreased, or did not change dose of narcotics/opioids. The most common AE was diminished or loss of pain relief in 11.4% of enrolled patients. CONCLUSIONS: Most patients experienced substantial pain relief and a significant improvement in all outcome measures. These results further support the safety, efficacy, and sustainability of SCS in clinical practice.

Spinal stimulator peri-electrode masses: case report.

The authors describe a case of delayed spastic quadriparesis caused by a peri-electrode mass following the implantation of a minimally invasive percutaneous spinal cord stimulator (SCS). Prior reports with paddle-type electrodes are reviewed, and a detailed histological and pathophysiological comparison with the present case is made. The patient developed tolerance to a cervical percutaneous SCS 4 months after implantation, followed by the onset of spastic quadriparesis 9 months after implantation. The stimulator was removed, and contrast-enhanced MRI revealed an enhancing epidural mass where the system had been placed, with severe spinal cord compression. Decompression was carried out, and the patient experienced neurological improvement. Pathological examination revealed fibrotic tissue with granulomatous and multinucleated giant cell reactions. No evidence of infection or hemorrhage was found. Professionals treating patients with SCSs or contemplating their insertion should be aware of this delayed complication and associated risk factors.

Effectiveness of cervical spinal cord stimulation for the management of chronic pain.

INTRODUCTION: Scientific evidence supports spinal cord stimulation (SCS) as a cost-effective treatment option that, for many disease states, should be employed earlier in the treatment continuum. Reimbursement for SCS in the cervical spine has recently been challenged based on supposed lack of clinical literature. To refute this assumption, we analyzed data from an international registry to support the use of cervical SCS. MATERIALS AND METHODS: The following outcomes were collected as part of an institutional review board-approved, prospective, multicenter, international registry: pain relief, Pain Disability Index (PDI) score, quality of life (QoL), and satisfaction at 3, 6, and 12 months post-implantation. Descriptive statistics are provided for all measures. Changes from baseline in PDI scores were analyzed using Tukey's pairwise comparisons. RESULTS: Thirty-eight patients underwent implantation of SCS leads in the cervical spine at 16 study sites in the United States and 3 international study sites. Direct patient report of percentage of pain relief was 54.2%, 60.2%, and 66.8% at 3, 6, and 12 months post-implantation, respectively. Pain relief was categorized as excellent/good by 61.6% of patients at 3 months, with similar results observed at 6 and 12 months. PDI scores were significantly reduced at all time points. At 3 months post-implantation, 92.4% of patients indicated they were very satisfied/satisfied with the SCS device. No patients indicated that they were dissatisfied. Overall QoL was reported as improved/greatly improved by 73.1% of patients at 3 months. Similar results for QoL and satisfaction were reported at 6 and 12 months. CONCLUSION: The results suggest that the use of SCS in the cervical spine is a medically effective method of pain management that satisfies and improves the QoL of most patients. The use of SCS can reduce the high cost of direct medical treatment of pain, as well as increasing the productivity of patients, and therefore should be reimbursed in appropriately selected patients.

Occipital peripheral nerve stimulation in the management of chronic intractable occipital neuralgia in a patient with neurofibromatosis type 1: a case report.

INTRODUCTION: Occipital peripheral nerve stimulation is an interventional pain management therapy that provides beneficial results in the treatment of refractory chronic occipital neuralgia. Herein we present a first-of-its-kind case study of a patient with neurofibromatosis type 1 and bilateral occipital neuralgia treated with occipital peripheral nerve stimulation. CASE PRESENTATION: A 42-year-old Caucasian woman presented with bilateral occipital neuralgia refractory to various conventional treatments, and she was referred for possible treatment with occipital peripheral nerve stimulation. She was found to be a suitable candidate for the procedure, and she underwent implantation of two octapolar stimulating leads and a rechargeable, programmable, implantable generator. The intensity, severity, and frequency of her symptoms resolved by more than 80%, but an infection developed at the implantation site two months after the procedure that required explantation and reimplantation of new stimulating leads three months later. To date she continues to experience symptom resolution of more than 60%. CONCLUSION: These results demonstrate the significance of peripheral nerve stimulation in the management of refractory occipital neuralgias in patients with neurofibromatosis type 1 and the possible role of neurofibromata in the development of occipital neuralgia in these patients.

Ultrasound imaging and occipital nerve stimulation.

OBJECTIVES: Occipital nerve stimulation (ONS) is a peripheral nerve stimulation (PNS) technique that has been used with success in the management of intractable chronic daily headaches (CDHs) and occipital neuralgia (ON). The technique involves the placement of a stimulating surgical or percutaneous electrode over the occipital nerves within the subcutaneous tissues at the skull base. Until recently, procedures involving the occipital nerves were based on identifying bony or arterial landmarks with direct palpation or fluoroscopy. Although universally accepted as an imaging technique, fluoroscopy does not provide real-time imaging of the occipital nerves or vessels. Furthermore, therapeutic efficacy of ONS is directly related to the ability of the stimulating electrode to produce peripheral nerve dermatomal paresthesia, emphasizing the need for precision placement. MATERIALS AND METHODS: A total of six patients, diagnosed with refractory CDH and ON, after failing extensive medical management, were diagnosed as potential candidates for ONS. Subsequently, all underwent successful percutaneous trials of bilateral octopolar (Advanced Neuromodulation Systems, Plano, TX, USA) ONS under ultrasound guidance, followed by permanent surgical implantation. RESULTS: In this case series, ultrasound provided accurate, real-time placement of introducer needles and stimulating electrodes by allowing visualization of tissue planes (epidermis, dermis, subcutaneous fat, and trapezious muscle), as well as vessels and nervous structures. CONCLUSIONS: Ultrasound imaging has been used increasingly for peripheral nerve blockade in surgical anesthesia and in chronic pain management as it allows real-time localization of both nervous and vascular structures (color flow Doppler) and, thus, a method for increasing blockade precision and safety. As an adjunct to ONS, the position of the introducer needles and electrodes can be visualized in relation to the occipital nerves and vasculature. This reproducible positioning allows accurate depth of placement (assuring production of the prerequisite PNS dermatomal paresthesia required for ONS efficacy) and limits the risk of injury to the occipital artery or nerve(s). In this case series, ultrasonography provided real-time, safe, and reliable placement of ONS electrodes. It also allowed identification of nervous and vascular structures unable to be seen with fluoroscopy, The portable nature of modern ultrasound machines, together with an ever improving pixelation of the Doppler color flow images/real-time measurements, and a lack of radiation exposure make this technology an attractive emerging modality in the field of Neuromodulation.

Successful treatment of charcot-marie-tooth chronic pain with spinal cord stimulation: a case study.

OBJECTIVES: Charcot-Marie-Tooth (CMT) disease is one of the most common hereditary neuropathies affecting one in 2500 people in the United States. CMT disease is associated with moderate to severe chronic extremity pain. We present the case of a young man with chronic intractable lower extremity pain associated with CMT disease treated with spinal cord stimulation (SCS). MATERIALS AND METHODS: This was an Institutional Review Board-approved case study involving a 37-year-old man diagnosed with CMT disease with pain of more than 20 years. He was implanted with an SCS device and patient pain and quality of life was assessed one and six months later using the SF-McGill Pain Questionnaire, Visual Analog Scale, Oswestry Disability Questionnaire, Pain Disability Index, and SF-36. Baseline measures were obtained retrospectively. Qualitative data were collected from the medical record. RESULTS: SCS was effective in decreasing pain, improving quality of life and reducing medication consumption at both one and six months post-implant. In addition, the patient was satisfied with SCS treatment. CONCLUSION: SCS produced favorable results in a patient with CMT and should be considered a treatment option for pain resulting from this condition.