Prospective Study on Ennovate® Pedicle Screw Fixation in Isthmic Spondylolisthesis Patients

Study Overview
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Brief Summary
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The present study is planned to demonstrate the efficacy and safety of a new pedicle screw system for the specific indication of isthmic spondylolisthesis, as this condition concerns relatively young patients requiring good fixation of the performed reposition to come to satisfactory clinical results.

Detailed Description
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Adult Isthmic spondylolisthesis, which is associated with spondylolysis, is defined as an osseous discontinuity of the vertebral arch at the isthmus (the pars interarticularis), which usually occurs in the fifth lumbar vertebra. The prevalence of isthmic spondylosis is proposed to be about 6% to 26% in different studies. The European Spine Tango registry found 15%. It is proposed to affect more men than women. Conservative treatments including braces, physical therapy, and medication are shown to be effective for some patients; however, surgical treatments are mainly the final effective treatment. There are several different options for surgery among which posterolateral fusion (PLF) is considered as the method of choice. It is shown that PLF is more effective than conservative treatments such as exercise. The fusion helps to fix the motion of the affected segment and therefore, might lead to pain reduction. Decompression, supplemental instrumentation, and supplemental anterior column support are also considered for treatment. These treatment strategies can be used separately or in any combination; however, studies trying to compare separate treatments with a combination of them have led to inconsistent results. Supplementary pedicle screws might be added to fusion methods for fixation and it is proposed that they have the ability to correct the deformity, reduce the listhesis, and increase the fusion rates, although a majority of the studies comparing instrumented PLF and noninstrumented PLF could not show the superiority of instrumented approaches. The literature has been reviewed in 2000 already, and the method has already been proved to be practical, safe, and effective for various spinal indications. Other authors found a better result for isthmic spondylolisthesis patients with posterior lumbar interbody Fusion (PLIF), vs. PLF, especially for high grade isthmic spondylolisthesis. The present study is planned to demonstrate the efficacy and safety of a new pedicle screw system for the specific indication of isthmic spondylolisthesis, as this condition concerns relatively young patients requiring good fixation also in the long-term.

Official Title
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Prospective Study on Clinical and Radiological Results With Ennovate® Pedicle Screw Fixation in Isthmic Spondylolisthesis Patients

Conditions
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Spine Fusion, Isthmic Spondylolisthesis

Intervention / Treatment
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* Device: fusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Symptomatic single-level IS (L4-S1), (VAS > 30mm, treated conservatively for a minimum of 6 months) Isthmic Spondylolisthesis Meyerding grade I and II Signed Informed Consent of the patient regarding the participation in this study Exclusion Criteria: Multilevel IS Severe degenerative changes of cranial adjacent level (disc height of <50% of the next healthy segment, Previous lumbar spine surgery except microdiscectomy or micro- decompression of the index level Patients psychically or mentally not able to give or refuse consent Patients psychically or mentally not able to answer the questions regarding their health status and quality of life Pregnancy (current or planned) BMI >35 Systemic or local infection Chemotherapy or radiation ongoing Desire of early retirement (running pension request) All contraindications as listed in the instructions for use

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Ennovate<br>Implantation of an Ennovate® internal fixation | Device: fusion<br>* Internal fixation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg pain | Leg Pain measured by Visual analogue scale (VAS) after 1 year follow-up: measured by Visual Analogue Scale: The visual analogue scale or visual analog scale (VAS) is a psychometric response scale which can be used in questionnaires. It is a measurement instrument for subjective characteristics or attitudes that cannot be directly measured. When responding to a VAS item, respondents specify their level of agreement to a statement by indicating a position along a continuous line between two end-points. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg Pain | Leg Pain measured by Visual analogue scale (VAS) at all timepoints except 1 year; measured by Visual Analogue Scale: The visual analogue scale or visual analog scale (VAS) is a psychometric response scale which can be used in questionnaires. It is a measurement instrument for subjective characteristics or attitudes that cannot be directly measured. When responding to a VAS item, respondents specify their level of agreement to a statement by indicating a position along a continuous line between two end-points. | Preoperative, 3 months, 6 months | 
| Back Pain | Back Pain measured by Visual analogue scale (VAS) at all timepoints; measured by Visual Analogue Scale: The visual analogue scale or visual analog scale (VAS) is a psychometric response scale which can be used in questionnaires. It is a measurement instrument for subjective characteristics or attitudes that cannot be directly measured. When responding to a VAS item, respondents specify their level of agreement to a statement by indicating a position along a continuous line between two end-points. | Preoperative, 3 months, 6 months, 1 year | 
| Functional Disability | Measured by Oswestry Disability Index (ODI) at all timepoints; The ODI is an index derived from the Oswestry Low Back Pain Questionnaire to quantify disability for low back pain. The self-completed questionnaire contains ten Topics: intensity of pain, lifting, ability to care for oneself, ability to walk, ability to sit, sexual function, ability to stand, social life, sleep quality, and ability to travel. Each topic category is followed by 6 statements describing different potential scenarios in the patient's life relating to the topic. Each question is scored on a scale of 0-5 with the first statement being zero and indicating the least amount of disability and the last statement is scored 5 indicating most severe disability. The scores for all questions answered are summed, then multiplied by two to obtain the index (range 0 to 100). Zero is equated with no disability and 100 is the maximum disability possible. | Preoperative, 3 months, 6 months, 1 year | 
| Patient satisfaction | Patient Satisfaction with Operation Result (very high / high / medium / low / very low) | 3 months, 6 months, 1 year | 
| Quality of Life | Quality of Life measured by EQ-5D-5L Questionnaire: The 5-level EQ-5D version (EQ-5D-5L) was introduced by the EuroQol Group in 2009 to improve the instrument's sensitivity and to reduce ceiling effects, as compared to the EQ-5D-3L. The EQ-5D-5L essentially consists of 2 pages: the EQ-5D descriptive system and the EQ visual analogue scale (EQ VAS). The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety / depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. This decision results in a 1-digit number that expresses the level selected for that dimension. The digits for the five dimensions can be combined into a 5-digit number that describes the patient's health state. | preoperative, 3 months, 6 months, 1 year | 
| Clinical Complications | Adverse Events (AE) and Serious Adverse Events (SAE) forms filled at all timepoints intraop and postop | intraoperative, 3 months, 6 months, 1 year | 
| Fusion status | Fusion assessment (acc. to Bridwell) | 3 months, 6 months, 1 year | 
| Radiographically assessed complications | Construct stability, loosening, implant breakage, other adverse events (Osteolysis, screw misplacement, device migration) | 3 months, 6 months, 1 year | 
| Loss of Reduction of the Reposition [degree] | Results regarding the maintenance of the reposition of the isthmic spondylolisthesis throughout the follow-up; loss of reduction during follow-up measured in [degree] | 3 months, 6 months, 1 year | 
| Range of Motion | Range of motion (angular and translational; degrees/mm) | 3 months, 6 months, 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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isthmic spondylolisthesis