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Carbon Fiber

Anti-Infective Agents, Local

Transpedicular spinal stabilization using a radiolucent composite system made of carbon fibers and PEEK followed by stereotactic radiotherapy of the spine at a dose of 5x5 Gy (25 Gy in the total dose)

Transpedicular spinal stabilization using a titanium system followed by stereotactic radiotherapy of the spine at a dose of 5x5 Gy (25 Gy in the total dose)

Transpedicular spinal stabilization using a titanium system preceded with stereotactic spine radiotherapy at a dose of 5x5 Gy (25 Gy in the total dose) as the first stage of treatment

Transpedicular stabilization with carbon fiber and PEEK-based implants in one of the two possible variants - first involves a large skin incision and separation of the back extensor muscles; second is associated with minimally invasive, which is percutaneous procedure that allows the stabilization with implants without the need to detach the muscles, using only a small skin incision.

Transpedicular spinal stabilization - carbon fibers-based implants

Transpedicular stabilization with titanium implants in one of the two possible variants - first involves a large skin incision and separation of the back extensor muscles; second is associated with minimally invasive, which is percutaneous procedure that allows the stabilization with implants without the need to detach the muscles, using only a small skin incision.

Transpedicular spinal stabilization - titanium implants

Spinal tumors will be treated with stereotactic body radiotherapy at a dose of 5x5 Gy (25 Gy in a total dose); either prior to or post-surgical treatment, accordingly the allocation to one of the study arms.

Stereotactic body radiotherapy

Kamil Krystkiewicz, PhD

Marcin Tosik, PhD

Krystkiewicz

Background: Spinal metastatic disease constitute a serious clinical problem in oncology. Bones are the third most common organ where metastases are located, and the spine is the place where they are most often located. Due to the complexity of the clinical problem, metastatic spine disease remains of interest to many medical specialties: neurosurgery, orthopedics, clinical oncology, radiotherapy and rehabilitation. With the development of modern diagnostic methods and wider access to them, the demand for neurosurgical treatment in this group of patients is growing. Surgical treatment is undertaken in cases of spinal cord compression, instability, spinal deformation or pain that is resistant to radiotherapy. The standard treatment in most cases is posterior instrumentation of the spine using titanium pedicle screws. Unfortunately, these systems cause numerous artifacts in diagnostic imaging, both in CT and MRI. These distortions make it difficult to plan radiotherapy and determine the optimal dose that would avoid healthy tissues. Moreover, artifacts could make difficult postoperative follow-ups aimed at assessing local recurrence. The solution to these problems is the use of radiolucent implants. There are systems based on carbon fibers embedded in PEEK which do not cause typical artifacts for titanium implants.

Study plan: The open, three-arm, prospective randomized study is planned to involve 226 patients with metastatic disease of the spine, with a known or undiagnosed primary site. Patients will be qualified for 2 types of interventions. The first one includes treatment with stereotactic radiotherapy (SBRT) in the first stage of treatment and early instrumentation of the spine with titanium implants. The second type of intervention includes patients qualified for surgical treatment using spine stabilization and postoperative SBRT. Patients within this arm will be randomized into two groups differing in the type of material the instrumentation is made of: carbon-PEEK or titanium. The study group will be patients stabilized with carbon implants, and the control group will be those who will have titanium implants.

Study population: The study includes adult patients with metastatic spine disease, with a known or unknown primary tumor, qualified for SBRT and surgical treatment.

Assumed effects: It is assumed that the treatment proposed in the project would extend progression free survival by several months or achieve local control in an additional 5% of patients. Moreover, by improving the quality of imaging, earlier diagnosis of local recurrences and implementation of appropriate locoregional treatment would be possible.

Carbon Fiber Transpedicular Screws in Treatment of Spinal Metastatic Disease

Carbon Fiber Transpedicular Screws in Treatment of Spinal Metastatic Disease and Stereotactic Radiotherapy

The use of convergence factor assessment will allow for comparison of similarity in planned SBRT between all groups. This will allow an indirect assessment of difficulties in planning treatment by a radiotherapist using objective tools.

Using a numerical scale from 0-10, the radiotherapist will assess the difficulty of planning, tumor coverage, and delineation of the spinal cord depending on the group assessed in the study.

Titanium instrumentation generates significant artifacts in radiological imaging used for radiotherapy planning. The use of opaque, radiolucent material allows for radiotherapy planning to cover a smaller area. This may reduce the incidence of radiation-related complications in nearby organs (OAR - organ at risk). These complications will be assessed by the radiation therapist according to the standardized NCI CTC scale. Potentially smaller quantity of organ complications could be an advantage supporting the use of carbon implants.

Titanium and carbon fiber show similar biocompatibility. The biomechanical properties of these materials are also similar. In vitro studies have shown a similar effect failure rate of carbon pedicle screws compared to standard titanium ones. However, carbon rods have greater flexibility and structure connected using these may show more frequent loosening in vivo, especially in cases with impaired sagittal balance. This was not an issue analyzed in the literature. The frequency of instrument failure is of great importance for clinical practice because most such cases require operative revision.

One of the goals of surgical treatment is to treat mechanical pain caused by segmental instability. SBRT is a good method of treating biological pain. There are no comparisons of analgesic effects between transpedicular systems. Greater pain reduction allows for more effective and longer ability to walk, lower consumption of painkillers, and lower incidence of complications related to immobilization (thrombosis, bedsores, respiratory infections), which also has pharmacoeconomic implications.

Postoperative wound infections are an inherent complication of surgical procedures. The longer the procedure, the more often inflammatory complications are observed, especially in oncological population, which has a higher average age of treated patients, a greater number of burdens, frequent immunosuppression due to systemic treatment, and malnutrition in the form of decreased biochemical parameters (total protein and albumin). Titanium has good properties in this aspect. Bacterial biofilms, is rarely formed on it, which means that patients can be treated more often without the need to remove the implants. It is unclear how carbon fiber system will perform in these cases. There are not made of metal, but of carbon fiber embedded in polymer. Assessment of the frequency of inflammatory complications and their course will provide the answer to whether This instrumentation allows for a similar management strategy in clinical settings.

Spots Global Cancer Trial Database for carbon fiber reinforced implants