RCT Study of the Gelstix™ Device to Treat Chronic Discogenic Low Back Pain GelStix Study (GelStix)

Randomized, Double-blind, Placebo-controlled, Multicenter Efficacy Study of the Gelstix™ Device to Treat Chronic Discogenic Low Back Pain

Degenerative Disc Disease is one of the most common spinal pathologies, affecting up to 10-15 % of adults. The purpose of this study is to evaluate the efficacy of treatment with the GelStix™ device in a patient population with discogenic pain that had no benefit from conservative care.

Degenerative Disc Disease (DDD) is one of the most common spinal pathologies, affecting up to 10-15 % of adults. The degeneration is associated with diminished water-binding capabilities of the nucleus pulpous leading to disc dehydration, volume reduction, changes in cellular activity, biomechanical changes and painful symptoms. Patients are initially treated with non-surgical pain-management techniques, such as anti-inflammatory medications and physical therapy, but these therapies often provide only temporary relief. When non-surgical intervention fails, fusion or total disc arthroplasty are often prescribed, both of which are highly invasive surgeries with significant associated morbidity. Clearly, a meaningful solution for the treatment gap existing between conservative care and invasive surgical intervention is needed. The purpose of this study is to evaluate the efficacy of treatment with the GelStix™ device in a patient population that had no benefit from conservative care. The primary objective of this study is to quantify the reduction in lumbar pain in a GelStix™ treatment group compared with a control group receiving a saline solution injection as placebo. The secondary objectives are to assess: Disability, using the Oswestry Disability Index (ODI) Quality of life (QoL), quantified with the European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L). The Patient's Global Impression of Change (PGIC) scale. This scale assesses the patient's own evaluation of improvement or deterioration over time on a 7-point Likert Scale rated from 'very much improved' to 'very much worse'. The use of pain medication The disc degeneration process will be assessed by means of MRI twelve months after treatment compared to baseline. Pfirrmann grade, disc height, and the presence of high intensity zones, Modic signs, and Schmorl's nodes will be recorded. The incidence and severity of complications and adverse events The total expected number of patients to be randomized is 72. Taking into account a relevant difference of 1.5 between groups on the NRS, with an SD of 2, 30 patients per group (60 patients in total) will be required to detect a statistically significant difference with a power of 80% at an alpha of 5% (two-tailed) for unpaired Student's T test. Taking into account a 20% drop out rate, 72 patients are expected to be randomized for this study. The estimated duration for the investigational plan (from start of screening of first participant to end of follow-up of last participant) is 24 months.

Pain intensity will be assessed employing an 11-point (i.e. 0-10) NRS with 0 meaning 'no pain' and '10' meaning 'worst possible pain'. Three times daily pain scores will be assessed for five consecutive days around the intended measurement time.

The mean NRS scores on the pain diary will be measured at baseline, and at one week, and one, three, six (primary outcome) and twelve months.

The ODI is a self-administered questionnaire, assessing the patient's level of pain and function during basic activities of daily living such as walking, personal care, standing, sleeping, etc.

This questionnaire assesses health related quality of life in terms of five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.49 Additionally, the EuroQol Visual Analogue Scale (EQ VAS) records the respondent's self-rated health on a 20 cm vertical, visual analogue scale with endpoints labelled 'the best health you can imagine'.

This scale assesses the patient's own evaluation of improvement or deterioration over time on a 7-point Likert Scale rated from 'very much improved' to 'very much worse'.

The Patient's Global Impression of Change (PGIC) scale will be measured at three, six and twelve months.

The use of pain medication will be assessed as the intake of analgesics at baseline, at one week, and at one, three, six and twelve months.

Pfirrmann grade, disc height, and the presence of high intensity zones (HIZ), Modic signs, and Schmorl's nodes will be recorded.

The disc degeneration process will be assessed by means of MRI twelve months after treatment compared to baseline.

The safety outcome of this study is the incidence and severity of complications and adverse events (AE's) including procedure-related complications at any time point in the study.

The incidence and severity of complications and adverse events are assessed at any time point in the study up to one year follow up.

Inclusion Criteria: discogenic pain caused by one or two levels of degenerative disc disease, confirmed by MRI and positive discography failure to have symptoms resolved or reduced following at least 12 weeks of conservative care (pain medication and/or physical therapy) negative medial branches block results baseline Numeric Rating Scale (NRS) pain score ≥5/10 Exclusion Criteria: radiculopathy disc herniations annular tear (greater than Grade 4 Modified Dallas Grading) coagulopathy or oral anticoagulant therapy (except low-dose acetylsalicylic acid) in conditions that do not allow for a temporary discontinuation previous lumbar surgery disc height less than 5 mm at the treatment level or less than 50% the original height BMI (Body Mass Index (kg/m2) of ≥ 35

Koetsier E, van Kuijk SMJ, Maino P, Dukanac J, Scascighini L, Cianfoni A, Scarone P, Kuhlen DE, Hollman MW, Kallewaard JW. Efficacy of the Gelstix nucleus augmentation device for the treatment of chronic discogenic low back pain: protocol for a randomised, sham-controlled, double-blind, multicentre trial. BMJ Open. 2022 Mar 30;12(3):e053772. doi: 10.1136/bmjopen-2021-053772.