8th September 2022
Two recent studies (Das1,2, Bosanquet3) explore the effect of neuromuscular electrostimulation (NMES), via common peroneal nerve stimulation, to increase blood flow within the wound edge and bed of leg ulcer patients. Both studies measured flux and pulsatility, key elements associated with wound healing and report significant increases in both – the latter is of particular pertinence, since pulsatile flow is a predicter of wound healing. The augmentative effect of NMES on the microcirculation, both in terms of flux and pulsatility, provide a mechanistic insight into its value in wound healing.
The NMES technology used in both studies is the geko™ device. Worn at the knee, the geko™ device gently stimulates the common peroneal nerve activating the calf and foot muscle pumps, resulting in increased venous, arterial and microcirculatory blood flow.
Das et al. (2020): Neuromuscular stimulation of the common peroneal nerve increases arterial and venous velocity in patients with venous leg ulcers
In a single centre open label study at Ealing Hospital’s wound clinic, Das et al. looked at the effect of 1 Hz neuromuscular stimulation on lower limb arterial and venous blood flow in 14 VLU patients. The geko™ device was applied to the patients – who had a median age of 68 years and were confirmed to have venous insufficiency. Patients’ wounds were all chronic, non-infected, and a minimum of 2cm and maximum 10cm in diameter.
Using Imaging Doppler Ultrasound, venous and arterial flow were measured in a seated and recumbent supine position. Results showed that the geko™ device had a significant effect (P < .001) on venous and arterial flow across both positions. Intermittent stimulation of these muscles activated the venous muscle pump helping VLU patients achieve improved venous and arterial velocity.
The geko™ device produced substantial and highly significant improvements in blood velocity in the large vessels of the patients’ legs. Unlike other NMES devices, geko™ can access the common peroneal nerve at a specific point close to the deep/superficial branch whereby both branches are stimulated resulting in a twitch in complex muscles of the leg.
The study reported the geko™ device was comfortable and well tolerated by patients, and quick and easy to apply. Furthermore, the geko™ device provided substantial increase of venous and arterial flow in the lower limb of patients with VLUs – an important part of managing VLUs.
Das (2021): Microcirculatory changes in venous leg ulcers using intermittent electrostimulation of common peroneal nerve
Das et al. later explored the effects of NMES devices on microcirculation in a wound bed and wound periphery. In this self-controlled, observational study, microcirculatory flow was examined using laser speckle contract imaging (LCSI) to determine whether muscle pump activation (via the geko™ device) increased microvascular flow in the wound bed and periwound across 16 VLU patients.
LCSI measures changes in microcirculatory flux in superficial blood vessels. This is considered an effective method of predicting the healing of VLUs. Flux measurements obtained from LSCI are unitless quantities that indicate the speed of particles within the blood vessels. Pulsatility – an indication of the strength of pulse in the signal – was also recorded in this study.
The median patient age was 68 and each patient had venous insufficiency. Results showed that geko™ augmented microcirculatory flow across the leg including the wound bed and areas in the wound periphery.
Pulsatility and flux were measured at the baseline, recording 12 units and 106 units respectively. The same parameters were recorded when the geko™ device was switched on with substantial growth recorded across both units; pulsatility was elevated to 102 units and mean flux increased to 224 units. Das et al. conclude that electrostimulation of the muscle pump leads to increased blood movement in the wound bed and periphery, both in continuous flux and pulsatility – two key elements associated with wound healing.
Bosanquet (2020): Microcirculatory flux and pulsatility in arterial leg ulcers is increased by intermittent neuromuscular electrostimulation of the common peroneal nerve.
Patients with arterial leg ulcers can show contraindications to compression therapy, requiring alternative solutions – such as NMES devices – to enhance blood flow to the peroneal nerve. In a single-centre open label study, Bosanquet et al. investigated the effects of the geko™ device on blood flow to the common peroneal nerve in patients with arterial leg ulcers.
Eight patients with ischemic lower limb wounds were prescribed the geko™ device. LSCI was used to investigate patterns of perfusion across the wound bed and edge measuring flux and pulsatility. Results showed that, in both locations, for all patients, there was a statistically significant increase in flux and pulsatility with the use of geko™. NMES enhanced flux at the wound bed by a mean of 64 percent and pulsatility by a mean of 452 percent; flux at the Peri-wound area increased by a mean of 37 percent and pulsatility by a mean of 188 percent.
Bosanquet et al. suggest that the geko device may also prove suitable for treating patients with arterial rest pain who are unsuitable for revascularization, even where wounds are not present, but further research is needed to confirm the clinical efficacy of the device in this area.
Evidence for NMES devices in wound healing
These studies provide valuable insights into the efficacy of NMES devices for leg ulcer patients across three key areas associated with wound healing: venous flow, microcirculatory flux, and pulsatility. Pulsatile flow is considered vital for wound healing, particularly in instances where contraindications to compression occur or when no intervention is available to improve macrovascular arterial supply.
The studies conclude that the geko™ device provides substantial augmentation of venous and arterial flow in the lower limb of patients with VLUs, though further research is required to confirm whether such devices can be applied for the long-term care of VLUs.