The Effect of Regenerative Peripheral Nerve Interface (RPNI) Surgery on Neuropathic Pain and Functional Outcomes in Major Lower Extremity Amputations
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 20
- 试验地点
- 1
- 主要终点
- Change in Pressure Pain Threshold (PPT)
研究概览
简要总结
This prospective, observational cohort study evaluates the long-term outcomes of Regenerative Peripheral Nerve Interface (RPNI) surgery in patients with major lower extremity amputations suffering from symptomatic neuromas. RPNI is a surgical technique where the transected nerve end is implanted into a free autologous muscle graft to serve as a physiological target for reinnervation. The study aims to objectively assess the reduction in mechanical hypersensitivity using Pressure Pain Threshold (PPT) measurements via a digital algometer. Additionally, it monitors subjective neuropathic pain levels, functional mobility, and prosthesis satisfaction over a 24-month follow-up period compared to pre-operative baselines.
详细描述
Scientific Rationale and Background Traditional "passive" nerve management techniques (e.g., traction neurectomy, burying in muscle/bone) often fail to prevent neuroma recurrence due to the lack of a physiological target for regenerating axons. This study investigates the long-term efficacy of the "Regenerative Peripheral Nerve Interface (RPNI)" technique. RPNI is an "active" surgical approach where the transected nerve end is implanted into a free autologous muscle graft to promote physiological reinnervation, thereby preventing chaotic axonal sprouting and neuroma formation.
Diagnostic Protocol (The Clinical Triad) To ensure accurate participant selection and strictly exclude non-neuroma pathologies such as Complex Regional Pain Syndrome (CRPS), the study employs a standardized "Clinical Triad" protocol for all potential candidates:
- Neuropathic Validation: Confirmation of neuropathic pain character via validated questionnaires.
- Anatomical Localization: Identification of a specific trigger point with a positive Tinel's sign triggering radiating paresthesia.
- Radiological Confirmation: Visualization of the neuroma bulb at the symptomatic site using high-resolution Diagnostic Ultrasound.
Surgical Methodology (Standard of Care) Participants undergo the standard RPNI procedure as per the clinic's routine protocol.
- Graft Harvesting: A free autologous muscle graft (approx. 30x15x5 mm) is harvested. To minimize donor site morbidity, graft selection is standardized based on the amputation level: Vastus Lateralis for transtibial amputees and Biceps Femoris for transfemoral amputees.
- Inlay Technique: The neuroma bulb is excised, and the fresh nerve end is implanted into the center of the muscle graft using the "Inlay Technique" to maximize neurotization interface and minimize axonal escape.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age: Adults aged 18 to 70 years.
- •Amputation Status: Unilateral major lower extremity amputation (Transtibial, Transfemoral, or Knee Disarticulation).
- •Radiological Baseline: Absence of Heterotopic Ossification (HO) in the residual limb, confirmed by pre-operative X-rays (Walter Reed Classification Grade 0).
- •Diagnosis: Confirmed diagnosis of "Symptomatic Neuroma" validated by the Clinical Triad:
- •Neuropathic Pain: DN4 Questionnaire score ≥
- •Pain Intensity: Numeric Rating Scale (NRS) score ≥
- •Physical Exam: Positive Tinel's sign or palpation tenderness at a specific trigger point.
- •Radiology: Diagnostic Ultrasound visualization of the neuroma bulb.
- •Surgical Indication: Scheduled for RPNI surgery as part of the routine standard of care treatment protocol due to prosthesis intolerance or severe pain.
- •Consent: Willing and able to provide informed consent and attend follow-up visits.
排除标准
- •CRPS: Diagnosis of Complex Regional Pain Syndrome (CRPS Type 1 or 2).
- •Concurrent Bone Surgery: Patients requiring simultaneous stump revision surgery (e.g., bone shortening, osteotomy, spur excision) or having existing HO (Walter Reed Grade > 0).
- •Systemic Conditions: Uncontrolled diabetes mellitus (HbA1c > 8.5%) or severe peripheral arterial disease compromising wound healing.
- •Cognitive Status: Cognitive impairment or psychiatric conditions preventing reliable completion of patient-reported outcome measures (PEQ, DN4).
- •History: Previous RPNI surgery at the same site (Recurrent RPNI cases).
研究组 & 干预措施
RPNI Group
Adult patients (18-70 years) with unilateral major lower extremity amputations (transtibial or transfemoral) who are diagnosed with "Symptomatic Neuroma" confirmed by the clinical triad (DN4 score ≥4, positive Tinel sign, and diagnostic ultrasound). These patients are scheduled to undergo Regenerative Peripheral Nerve Interface (RPNI) surgery as part of the routine standard of care treatment protocol.
干预措施: Regenerative Peripheral Nerve Interface (RPNI) Surgery (Procedure)
结局指标
主要结局
Change in Pressure Pain Threshold (PPT)
时间窗: Baseline (Pre-op), 3, 6, 12, and 24 months post-operation.
Objective measurement of mechanical hypersensitivity at the neuroma site using a digital pressure algometer. The device applies increasing pressure in kg/cm² until the patient reports pain. Measurements are taken from the most tender point of the neuroma and a control point. Higher values indicate higher pain tolerance (improvement).
次要结局
- Daily Prosthesis Usage Time (DPUT)(Baseline, 3, 6, 12, and 24 months.)
- Change in Pain Intensity (NRS)(Baseline, 3, 6, 12, and 24 months.)
- Change in Neuropathic Pain Characteristics (DN4 Score)(Baseline, 3, 6, 12, and 24 months.)
- Prosthesis Satisfaction and Quality of Life (PEQ)(Baseline, 3, 6, 12, and 24 months.)
- Change in Functional Mobility (TUG Test)(Baseline, 3, 6, 12, and 24 months.)
- Quality of Phantom Motor Execution (PME)(Baseline (Pre-op), 3, 6, 12, and 24 months post-operation.)
- Severity of Viscero-Somatic Convergence Symptoms(Baseline (Pre-op), 3, 6, 12, and 24 months post-operation.)
- Incidence of New Heterotopic Ossification (HO)(Baseline (Pre-op) and 24 months post-operation.)
研究者
Ahmet Burak Bilekli
Associate Professor
Saglik Bilimleri Universitesi