Infection Rates of Electrical Leads Used for Percutaneous Neurostimulation of the Peripheral Nervous System

Abstract

Background: Percutaneous neurostimulation of the peripheral nervous system involves the insertion of a wire "lead" through an introducing needle to target a nerve/plexus or a motor point within a muscle. Electrical current may then be passed from an external generator through the skin via the lead for various therapeutic goals, including providing analgesia. With extended use of percutaneous leads sometimes greater than a month, infection is a concern. It was hypothesized that the infection rate of leads with a coiled design is lower than for leads with a noncoiled cylindrical design.

Methods: The literature was retrospectively reviewed for clinical studies of percutaneous neurostimulation of the peripheral nervous system of greater than 2 days that included explicit information on adverse events. The primary endpoint was the number of infections per 1,000 indwelling days.

Results: Forty-three studies were identified that met inclusion criteria involving coiled (n = 21) and noncoiled (n = 25) leads (3 studies involved both). The risk of infection with noncoiled leads was estimated to be 25 times greater than with coiled leads (95% confidence interval [CI] 2 to 407, P = 0.006). The infection rates were estimated to be 0.03 (95% CI 0.01 to 0.13) infections per 1,000 indwelling days for coiled leads and 0.83 (95% CI 0.16 to 4.33) infections per 1,000 indwelling days for noncoiled leads (P = 0.006).

Conclusions: Percutaneous leads used for neurostimulation of the peripheral nervous system have a much lower risk of infection with a coiled design compared with noncoiled leads: approximately 1 infection for every 30,000 vs. 1,200 indwelling days, respectively.

Keywords: helical lead; neuromodulation; percutaneous peripheral nerve stimulation; peripheral nerve stimulator; postoperative pain; small-diameter open-coiled helical lead.

Figure 1

Examples of (A) a coiled lead and (B) a noncoiled electrical lead used for percutaneous neurostimulation of the peripheral nervous system.

Figure 2

Example of a coiled fluoropolymer insulated lead and fibrosis at the insertion site, possibly leading to both a superior bacteriostatic seal at the skin and a solid anchor preventing lead movement. Exposed, finely coiled 0.2 mm diameter stainless steel wire makes up the active electrode, with the distal portion bent to facilitate anchoring in the tissue. (Reprinted with permission from Corey 1990.)

Figure 3

Infection rates for coiled and noncoiled leads used for percutaneous neurostimulation of the peripheral nervous system reported as (A) infections per 1,000 indwelling days (individual study infection rates represented with circles along the axis of the log scale identify infection rates of <0.01) and (B) infection rates during the first 30 and 60 indwelling days.