Preoperative Transcutaneous Electrical Nerve Stimulation and Ultrasound

Preoperative Transcutaneous Electrical Nerve Stimulation and Ultrasound: a Mapping Protocol to Minimize Cutaneous Nerve Damage During ACL Surgery Results Introduction • Iatrogenic nerve injury is a common problem in procedures such as ACL surgery where there is little intraoperative regard for cutaneous innervation • Damage to cutaneous nerves during ACL surgery leads to painful neuromas and general pain in the knee region, directly affecting patients whose profession requires kneeling • There are few studies that investigate the precise locations of the femoral cutaneous nerve branches and infrapatellar branch of the saphenous nerve near the knee • Our goals: • 1.) Accurately map cutaneous nerves in the anterior thigh/knee region • 2.) Develop a screening protocol to help surgeons avoid cutting nerves Conclusion Fig. 4: Drawing of LFCN by Emma Schmidt • Ultimately, we hope to: • 1.) Improve knowledge of cutaneous innervation in the anterior thigh/knee regions through drawings to inform future education of medical students, clinicians, and anatomists • 2.) Provide a preoperative protocol that aids in avoiding iatrogenic nerve injury not only for ACL surgery but also other procedures Fig. 5: Drawing of AFCN, MFCN, and LFCN by Emma Schmidt Methods Fig. 1: Cadaveric dissection of the lateral femoral cutaneous nerve (LFCN) Fig. 2: Cadaveric dissection of the anterior femoral cutaneous nerve (AFCN) and medial femoral cutaneous nerve (MFCN) • Based on techniques used in Hu et al. and Natori et al. (2015)2 • We propose a combination of transcutaneous electrical nerve stimulation (TENS) and ultrasound (US) • US would first be used to locate and mark the nerve paths • A pen-type electrode connected to a TENS unit such as the Stimuplex® HNS 12 would then pinpoint sensory nerves based on patient feedback to confirm the US • Topographic maps created from cadaveric dissection assist in selecting areas to employ the US/TENS screening method Fig. 3: Stimuplex® HNS 12 TENS unit and 1 (2015) application of electrode pen