This prospective observational pilot study will evaluate structural, functional, and patient-reported outcomes in adults with small fiber neuropathy who receive Saluda Evoke ECAP-controlled spinal cord stimulation as part of routine clinical care. The study does not assign, direct, or modify spinal cord stimulation therapy. All decisions regarding patient selection, trial stimulation, permanent implantation, and device programming are made independently by the treating physician according to standard clinical practice.

The primary objective is to assess change in intra-epidermal nerve fiber density from baseline to 12 months. Secondary objectives include evaluation of quantitative sensory testing, pain intensity, patient-reported outcomes, and correlations between changes in nerve fiber density, sensory function, and neuropathic pain outcomes.

The study will enroll up to 10 adult participants with clinically diagnosed small fiber neuropathy and chronic neuropathic pain. Research assessments include patient-reported outcome measures, quantitative sensory testing, review of available clinical records, and a 12-month follow-up skin biopsy for intra-epidermal nerve fiber density.

This aligns with the approved protocol: observational, 10 adults, 12-month participant follow-up, primary IENFD endpoint, and secondary QST/pain/correlation endpoints.

Inclusion Criteria:

• Age 19 years or older.
• Clinically diagnosed small fiber neuropathy based on abnormal intra-epidermal nerve fiber density (IENFD) skin biopsy.
• Chronic neuropathic pain with Numeric Pain Rating Scale score of at least 6.
• Candidate for ECAP-controlled spinal cord stimulation therapy based on the - - - Principal Investigator's medical judgment.
• Able and willing to undergo baseline and 12-month skin biopsies.
• Able to comply with 12-month quantitative sensory testing.
• Able to provide informed consent.

Exclusion Criteria:

• Confounding factors that may independently contribute to small fiber damage or alter nerve fiber density, including uncontrolled diabetes defined as HbA1c greater than 8.5% within the last 3 months, autoimmune disorders such as lupus, or history of alcohol abuse.
• Contraindications to spinal cord stimulation therapy, including active infection, coagulation disorders, allergy to medical device components, or other relevant surgical/device contraindications.
• Uncontrolled medical or psychiatric conditions.
• Pregnancy or planning to become pregnant during the study period.

Individual participant data will not be shared. The study involves a small pilot cohort and includes clinical, device-related, biopsy, sensory testing, and patient-reported data that may increase the risk of participant re-identification. De-identified aggregate results may be reported in publications or presentations, subject to applicable IRB, privacy, sponsor, and regulatory requirements.