High-Frequency versus Low-Frequency Spinal Cord Stimulation in Treatment of Chronic Limb-Threatening Ischemia: Short-Term Results of a Randomized Trial.

INTRODUCTION: The objective of the study is to determine if high-frequency (1 kHz) spinal cord stimulation (SCS) is better than low-frequency SCS for pain relief in chronic limb-threatening ischemia (CLTI). METHODS: HEAL-SCS trial was designed as an open-label, parallel-group, single-center randomized study with a 1:1 allocation ratio. The trial was conducted in Meshalkin National Medical Research Center between August 2018 and February 2020. Total 56 patients underwent screening, 50 were enrolled, 6 were rejected. The participants were randomized into 2 cohorts of 25 patients each by an external coordinator using an online tool. A neurosurgeon and a vascular surgeon both examined all patients and estimated the pain intensity using visual analog scale (VAS), quality of life with short-form-36 health survey (SF-36), and functional status by walking impairment questionnaire (WIQ) at 3 and 12 months. Tissue perfusion was evaluated for 34 patients using transcutaneous oxygen tension measurement (TcPO2) at baseline and in 12 months. RESULTS: All 50 patients (84% men, median age 66.5 y.o) were available for primary outcome assessment 3 and 12 months after implantation. Intention-to-treat analysis demonstrated comparative advantage of HF-SCS over LF-SCS at 3 months with mean VAS score 2.8 (95% CI, 2.4; 3.2) and 3.3 (95% CI, 3.0; 3.6), respectively (p = 0.031). Clinical superiority of HF-SCS persisted at 12-month follow-up (p < 0.001). HF-SCS produced significantly greater pain relief by WIQ at 3 (p < 0.001) and 12 months (p = 0.009). Despite stair-climbing ability was better in HF-SCS group (p = 0.02), no significant difference between groups was found at 1-year post-op in terms of speed (p = 0.92) and distance scores (p = 0.68). Accordingly, the general and mental health domains of SF-36 were significantly better in HF-SCS at 12 months. Despite a tendency toward better resting oxygen pressure in HF-SCS group, there was no intergroup difference by TcPO2 (p = 0.076). Only 1 patient (2%) required above-the-knee amputation at 10 months after LF-SCS implantation. CONCLUSION: High-frequency SCS provides better pain relief, life quality, and functional performance in patients with CLTI during short-term follow-up. The lack of perfusion difference between high-frequency and conventional SCS requires further examination to the possible long-term advantages of the method.

The Clinical Outcomes in Patients with Critical Limb Ischemia One Year after Spinal Cord Stimulation.

BACKGROUND: The aim of this study was to evaluate the long-term outcomes of spinal cord stimulation in patients with critical limb ischemia and to test the hypothesis that the dynamics of clinical changes one year after therapy depend both on the clinical determinants associated with the underlying disease and on factors related to systemic atherosclerosis. METHODS: This prospective cohort study included 56 patients with critical limb ischemia. All patients before and after spinal cord stimulation were examined in terms of the dynamics of their clinical changes using the Rutherford scale and transcutaneous oxygen tension (TcPO2, mm Hg) in the affected foot. The active orthostatic test was used to assess the functional state of peripheral perfusion. RESULTS: One year after spinal cord stimulation, 74% of patients showed positive clinical outcomes. No changes were observed in 9.3% of patients, whereas adverse clinical outcomes were revealed in 16.7% of cases. The TcPO2 values were significantly reduced before spinal cord stimulation: 10.5 (6.4-16.0) mm Hg. The functional status of the peripheral microvasculature was also disturbed. One year after therapy, TcPO2 significantly increased and the adaptive mechanisms of the microvasculature were improved in more than 70% of patients. Logistic regression analysis showed that the initially low TcPO2 values (<10 mm Hg) with a lack of gain in TcPO2 during the orthostatic test are associated with the negative clinical outcomes after spinal cord stimulation. The gain in TcPO2 during the orthostatic test to >10 mm Hg is associated with the positive clinical outcomes after spinal cord stimulation. The age-adjusted Charlson Comorbidity Index >5 and duration of critical ischemic symptoms also had a negative effect on the clinical outcomes after spinal cord stimulation. CONCLUSIONS: The positive clinical outcomes were revealed in most patients with critical limb ischemia one year after spinal cord stimulation. The low values of peripheral tissue metabolism with the disturbed functional status of the microvasculature are associated with the negative clinical outcome. The patients with baseline TcPO2 <10 mm Hg can recover if they still have a sufficient microcirculatory reserve capacity. Duration of critical ischemic symptoms and high comorbidity burden with allowance for age are negative factors affecting the clinical outcome.

New Software for Preoperative Diagnostics of Meningeal Tumor Histologic Types.

OBJECTIVE: Meningeal tumors are neoplasms with different histologic manifestations of both benign and malignant types that determine the prognosis of tumor recurrence and its consistency. The risk of surgical treatment depends on the location, size, and consistency of the tumor. Magnetic resonance imaging (MRI) sequences can be used to identify the features of tumors, but these MRI characteristics are not well understood. The present study describes an advanced mathematical algorithm to analyze MRI data and distinguish histologic types of meningeal tumors before surgery. METHODS: Forty-eight patients underwent surgical removal of meningeal brain tumor. All patients had preoperative MRI with a 1.5-T scanner. One radiologist and 2 neurosurgeons evaluated MRI histogram peaks of the whole tumor volume using the advanced computer algorithm. RESULTS: Three specialists received the following mean value of histogram peaks: 15.99 ± 0.23 (± standard error of the mean [SEM]) for meningoteliomatous meningiomas; 21.24 ± 0.3 (±SEM) for fibroplastic meningiomas; 19.0 ± 0.28 (±SEM) for transitional meningiomas; 10.7 ± 0.27 (±SEM) for anatypical, anaplastic meningiomas, 11.03 ± 0.51 (±SEM) for primary intracranial fibrosarcomas and 25.72 ± 0.29 (±SEM) for meningeal hemangiopericytomas. A one-way analysis of variance test proved the difference between group means: F = 70.138, P < 0.01. The Tukey test and the Games-Howell test indicated that the difference between the tumor groups was significant. Mean deviation in agreement index between specialists was 0.98 ± 0.007 (±SEM). CONCLUSIONS: The advanced algorithm proved high specificity, sensitivity, and interoperator repeatability.