1. 2009;12;965-983Cross Talk: A New Method for Peripheral Nerve Stimulation. An Observational Report with Cadaveric Verification
   Observational Report
   Jeffrey Berger, MD, Alan Vrable, MD, Frank J.E. Falco, MD, Obi Onyewu, MD, and Jie Zhu, MD.

BACKGROUND: Relief of regional, non-appendicular pain, particularly low back pain, through spinal cord stimulation (SCS) has proven challenging. Recently, peripheral nerve stimulation (PNS), also known as peripheral nerve field stimulation (PNFS) depending on the stimulation area, has demonstrated efficacy for the treatment of well-localized, small areas of pain involving the abdomen, inguinal region, pelvis, face, occipital area, and low back. More widespread application of peripheral nerve stimulation has been limited by its narrow field of coverage in a larger group of patients with diffuse or poorly localized pain.

OBJECTIVES: To determine if cross talk (the creation of an electrical circuit and therefore electrical stimulation between separate subcutaneously placed PNS leads [i.e. inter-lead stimulation]) was clinically possible across large painful areas, assess the breadth of stimulation coverage via cross talk, evaluate the clinical efficacy of peripheral nerve stimulation cross talk (PNSCT), and confirm the existence of cross talk across a large area in a cadaveric model.

STUDY DESIGN: Case series observational report and cadaveric experimentation.

SETTING: A private, comprehensive interventional pain management practice with pain medicine fellowship training in the United States.

METHODS: Eighteen consecutive patients with non-appendicular, regional pain were included in the study. Data collection for the implanted patients included the presence or absence of stimulation between the PNS leads, stimulation tolerability, stimulation region, lead orientation, lead montage, inter-lead distance, and pain relief from PNSCT compared to PNS without cross talk.

A cadaveric analysis was performed to determine the presence or absence of an electrical circuit with 2 subcutaneously PNS leads to confirm or refute the existence of electrical stimulation from on lead to the other within subcutaneous fat with the leads placed at a significant distance apart from one another.

RESULTS: All 18 patients experienced significant pain relief, reduction of pain medication, and functional improvement. Cadaveric experimentation confirmed the presence of an electrical circuit with PNS leads placed at a distance far apart from one another and verified that inter-lead stimulation (cross talk) does occur in subcutaneous fat over a great distance.

LIMITATIONS: This study was limited by its small sample size, and the short-term follow-up after implantation.

CONCLUSIONS: The use of the PNSCT technique allows for significant analgesia for large painful areas that have been poorly captured using traditional SCS techniques and not considered as an option with the current application of peripheral nerve stimulation.