Pain Therapy Options: A patient-based outcome review of pain management devices

PainTech – Pain Therapy Options

A patient-based outcome review of pain management devices, including the Willow Curve

January/February 2019- Practical Pain Management Journal

Tiziano A. Marovino DPT, MPH, DAIPM Michael Majewski, BAA, CSCS


Chief Health Strategy and Innovation Officer Research Associate
Biogenesis Group, LLC TLC Group
Ypsilanti, MI Ypsilanti, MI

This device review focuses on technologies that have emerged over the past few years that aim to benefit patients suffering from persistent pain, as well as infuse some innovation into home-based chronic pain management. The current healthcare economy and milieu in general relies on patients passively receiving clinical services, making the directionality of healthcare provision from the home to the hospital or clinic. With healthcare reform and the anticipated transition from volume- to value-based care, the clinical community will need to give greater thought to filling the post-discharge void regarding pain relief typically associated with on-site services. If reimbursement models change to reflect a greater pay-for-performance model based on out­comes, whereby providers are paid commensurate with clinical effectiveness, this trend may incentivize caregivers/providers to consider improved home-based pain management, includ­ing the judicious use of durable medical equipment (DME).

The devices featured represent just a sampling of a much larger trend that may transform healthcare delivery in the near future, including transitions from expensive inpatient settings to less costly outpatient settings, and eventually into the home. In the current complex healthcare ecosystem, hav­ing the ability to leverage the right technology for individual patients moving forward will be paramount. In addition, having access to a cohesive evidence-informed home care plan for conservative chronic pain management will be vital to total care coordination when it comes to ensuring positive outcomes. The three technologies highlighted herein are sleek, cleverly designed, and, in the authors’ view, have demonstrated medical-grade pain management at a fraction of the price.

Data Methods & Analysis: Quantifying Patient Improvement

This mixed-methods analysis utilized patient-reported out­comes and provider research with quantitative endpoints. The goal was to determine how each device worked and in which patients it worked best. The authors used a traditional odds ratio (OR) statistic to measure effect size, since ORs do not require intensive computation. In our design, the OR was simply the ratio of two probabilities: the probability of achieving the outcome of interest vs the probability of not achieving the outcome of interest. In a conventional case/control design, the subjects would be chosen based on the presence or absence of disease. In our clinical setting, the subjects were chosen based on the presence or absence of pain. Using classic OR convention, the cases and the controls represent two different groups and differ only by disease status.

When pain intensity is used as the primary endpoint, one may actually have the pain at one point in the day and not have pain in another part of the day (diurnal variation). In this modified OR format, we used the same group of patients as both the cases and the controls, taking advantage of fluc­tuations in pain status. By doing so, we have avoided many of the confounding factors that require statistical adjustment. However, by not implementing the same level of internal control(s) as a formal clinical trial, the data can only infer association and not causation between outcome and expo­sure variables.

Product Evaluation

Since the three devices reviewed do not require medical prescription, our primary outcome measure of interest was patient-reported pain intensity reduction using a 10-point visual analog scale (VAS). These three devices were presented to us at different times of the year in 2018. The Willow Curve (phototherapy) and Quell (electrostimulation) devices were tested for 8 and 11 months, respectively, while the VibraCool (vibrational) device was tested over a period of 3 months (received in October 2018). We applied a single subject design (multiple N of 1) that examined the change in pain intensity based on a single treatment session where the patient acted as his or her own control with the desired outcome of interest being a 3-point reduction in a 10 point (10 cm) VAS scale.

As clinicians know, it is important to be reminded that pain intensity is but one characteristic in the total pain experience of any patient and does not necessarily explain co-existing disability. The use of a pain VAS instrument as a surrogate to measure disability is not ideal as it simply measures a single dimension of the pain experience: pain intensity. However, the VAS has been shown to compare favorably to multi-item scales, showing good concurrent validity (SF-20), responsiveness, and excellent reliability. In fact, while common forms of pain intensity assessment have shown excellent test-retest reliability, the VAS has the smallest error associated with its use.

Product protocols were followed according to device instructions and verified through numerous communications.

Description & Performance of the Devices

Product: Willow Curve

Manufacturer: Physician’s Technology, LLC (Monroe, MI)

Recommended for pain conditions such as: arthralgia (joint pain), neuralgia, and myalgia

Cost: Retail $799

* Please contact your MeyerDC Account Manager at the number below for Professional Pricing

Figure 1. Willow Curve

The Willow Curve (WC) is a curvilinear shaped device that fits snugly over the round contour of most joints and emits simultaneous thermal energy (heat) and photonic energy (light) within the infrared spectra, specifically the 500 to 4,000 nm wavelength range. The spectral or emis­sion frequency pattern of WC has been identified to be in the 292 to 4,000 Hz range. This device has been developed with sophisticated technology that combines the benefits of laser, infrared, and LEDs in a therapeutic and engineering conglomerate that culminates into clinical grade pain relief.

The mechanisms of action (MOA) are those consistent with a multitude of studies already documented in the low-level laser research literature base.

The WC offers a patient-friendly treatment with an ease of use that improves patient compliance. The LED array is both visible (red lights) and sensory (heat), which helps counteract the possibility of “nocebo” effects often seen in the more silent therapies that have no visual or auditory cues. The treatment generally takes under 30 minutes and patients are put in a comfortable position for the duration. The WC performs very well with joint conditions (arthralgia) given its structural configuration, which provides a snug contoured fit around most joints and the cervical spine as well. The WC was trialed on a variety of musculoskeletal (MSK) con­ditions including the various arthritides (OA/RA/psoriatic/gout), joint injury (sprains/strains), post-surgical pain, and “age-related” (idiopathic) pain and stiffness.

Our experience with the WC device was quite rewarding, in that we were not expecting such strong treatment effects. We continue to use the WC as part of our daily clinical treatments for chronic pain patients.


The technologies described are unique from each other and represent divergent technologies with convergent goals. They are a good example of how many different ways one may achieve cost-effective pain control. When used on a regular basis, these devices have demonstrated that they can modulate both acute and chronic pain and could make excellent home pain management options. Pain practitioners may want to consider adopting these devices for clinical use as well, or at least so that patient trials may be conducted in-office to determine response and whether a medical order for the device is warranted.

Our data suggest that these diverse devices are effective at ameliorating pain intensity and are proof that there are many ways to peel the proverbial onion.

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