Carbon Fiber Transpedicular Screws in Treatment of Spinal Metastatic Disease

• Transpedicular spinal stabilization - carbon fibers-based implants (Procedure): 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 - titanium implants (Procedure): 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.
• Stereotactic body radiotherapy (Radiation), also known as SBRT: 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.

Primary outcomes

• The assessment of time to local recurrence after treatment with SBRT. [5 years]
• The assessment of frequency of local recurrence after treatment with SBRT. [5 years]

Secondary outcomes

• DICE convergence factor evaluation between groups of patients. [1 day]: 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.
• The subjective difficulty of planning radiotherapy treatment. [1 day]: 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.
• The frequency of radiation complications assessed according to the National Cancer Institute Common Toxicity Criteria (NCI CTC). [5 years]: 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.
• Failure rate of stabilizing systems. [5 years]: 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.
• Pain assessment on the VAS scale between groups. [5 years]: 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.
• Frequency of postoperative infections. [5 years]: 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.
• Differences in dosimetric parameter Dmin PTV/CTV. [1 day]
• Differences in dosimetric parameter D95. [1 day]
• Differences in dosimetric parameter D98. [1 day]
• Differences in dosimetric parameter D100. [1 day]
• Differences in dosimetric parameter conformity index (CI) / homogeneity index (HI)). [1 day]

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Metastatic spinal disease,
* ECOG quality of life of 0-2,
* Eligibility for SBRT treatment,
* Expected survival time >3 months,
* Signed informed consent to participate in the study,
* Sufficient organ capacity allowing to survive the perioperative period.

Exclusion Criteria:

* Primary tumor of the spine,
* Age <18 years old,
* Expected survival time <3 months,
* Eligibility for palliative radiotherapy,
* No informed consent to participate in the study,
* Pregnancy or breastfeeding,
* The advancement of the disease preventing the technical use of implants.

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• Results publication: Krystkiewicz K, Kuncman L, Orzechowska MJ, Pytlarz B, Kowal A, Siwak M, Fijuth J, Ranoszek K, Pajdzinski M, Zubiel K, Arczewski F, Dziedzic K, Tosik M. CARBOMETASPINE: protocol for a multicenter, prospective, randomized controlled trial of carbonfiber spinal fixation in metastatic disease. BMC Cancer. 2025 Sep 2;25(1):1409. doi: 10.1186/s12885-025-14731-7. PMID 40898139

• Informed Consent Form (PDF, 2025-05-09)

• Kamil Krystkiewicz, PhD, Principal investigator, Department of Neurosurgery and Neurooncology, Copernicus Memoriał Hospital in Łódź