Evaluation of computed tomography artefacts of carbon-fiber and titanium implants in patients with spinal oligometastatic disease undergoing stereotactic ablative radiotherapy

This study evaluated artefacts on computed tomography (CT) images using Hounsfield units (HU) in patients with spinal oligometastatic disease who received carbon-fiber (CF; n = 11) or titanium (n = 11) spine implants and underwent stereotactic ablative radiotherapy (SABR). Pre- and postoperative HU were measured at the vertebral body, pedicle, and spinal cord at three different levels: the lower instrumented vertebra, the level of metastatic spinal cord compression, and an uninvolved level. Areas measured at each level were delicately matched pre- and postoperatively. Significant differences in HU were observed at the vertebral body, the pedicle, and the spinal cord at the lowest instrumented vertebra level for both CF and titanium (average increase 1.54-fold and 5.11-fold respectively). At the metastatic spinal cord compression level, a trend towards a higher HU-increase was observed in titanium compared with CF treated patients (average increase 2.51-fold and 1.43-fold respectively). The relatively high postoperative HU-increase after insertion of titanium implants indicated CT artefacts, while the relatively low HU-increase of CF implants was not associated with artefacts. Less CT artefacts could facilitate an easier contouring phase in radiotherapy planning. In addition, we propose a CT artefact grading system based on postoperative HU-increase. This system could serve as a valuable tool in future research to assess if less CT artefacts lead to time savings during radiotherapy treatment planning and, potentially, to better tumoricidal effects and less adverse effects if particle therapy would be administered.

Outcomes of Long Bones Treated With Carbon-Fiber Nails for Oncologic Indications: International Multi-institutional Study

BACKGROUND

Intramedullary nail fixation is commonly used for prophylactic stabilization of impending and fixation of complete pathological fractures of the long bones. However, metallic artifacts complicate imaging evaluation for bone healing or tumor progression and postoperative radiation planning. Carbon-fiber implants have gained popularity as an alternative, given their radiolucency and superior axial bending. This study evaluates incidences of mechanical and nonmechanical complications.

METHODS

Adult patients (age 18 years and older) treated with carbon-fiber nails for impending/complete pathological long bone fractures secondary to metastases from 2013 to 2020 were analyzed for incidences and risk factors of mechanical and nonmechanical complications. Mechanical complications included aseptic screw loosening and structural failures of host bone and carbon-fiber implants. Deep infection and tumor progression were considered nonmechanical. Other complications/adverse events were also reported.

RESULTS

A total of 239 patients were included; 47% were male, and 53% were female, with a median age of 68 (IQR, 59 to 75) years. Most common secondary metastases were related to breast cancer (19%), lung cancer (19%), multiple myeloma (18%), and sarcoma (13%). In total, 17 of 30 patients with metastatic sarcoma received palliative intramedullary nail fixation for impending/complete pathological fractures, and 13 of 30 received prophylactic nail stabilization of bone radiated preoperatively to manage juxta-osseous soft-tissue sarcomas, where partial resection of the periosteum or bone was necessary for negative margin resection. 33 (14%) patients had complications. Mechanical failures included 4 (1.7%) structural host bone failures, 7 (2.9%) implant structural failures, and 1 (0.4%) aseptic loosening of distal locking screws. Nonmechanical failures included 8 (3.3%) peri-implant infections and 15 (6.3%) tumor progressions with implant contamination. The 90-day and 1-year mortalities were 28% (61/239) and 53% (53/102), respectively. The literature reported comparable failure and mortality rates with conventional titanium treatment.

CONCLUSIONS

Carbon-fiber implants might be an alternative for treating impending and sustained pathological fractures secondary to metastatic bone disease. The seemingly comparable complication profile warrants further cohort studies comparing carbon-fiber and titanium nail complications.

Carbon-fibre plates for traumatic and (impending) pathological fracture fixation: Where do we stand? A systematic review

BACKGROUND

Carbon-fibre (CF) plates are increasingly used for fracture fixation. This systematic review evaluated complications associated with CF plate fixation. It also compared outcomes of patients treated with CF plates versus metal plates, aiming to determine if CF plates offered comparable results. The study hypothesized that CF plates display similar complication rates and clinical outcomes as metal plates for fracture fixation.

METHODS

The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following databases were searched from database inception until June 2023: PubMed, MEDLINE, Embase, Web of Science, Cochrane Library, Emcare, Academic Search Premier and Google Scholar. Studies reporting on clinical and radiological outcomes of patients treated with CF plates for traumatic fractures and (impending) pathological fractures were included. Study quality was assessed, and complications were documented as number and percentage per anatomic region.

RESULTS

A total of 27 studies of moderate to very low quality of evidence were included. Of these, 22 studies (800 patients, median follow-up 12 months) focused on traumatic fractures, and 5 studies (102 patients, median follow-up 12 months) on (impending) pathological fractures. A total of 11 studies (497 patients, median follow-up 16 months) compared CF plates with metal plates. Regarding traumatic fractures, the following complications were mostly reported: soft tissue complications (52 out of 391; 13%) for the humerus, structural complications (6 out of 291; 2%) for the distal radius, nonunion and structural complication (1 out of 34; 3%) for the femur, and infection (4 out of 104; 4%) for the ankle. For (impending) pathological fractures, the most frequently reported complications were infections (2 out of 14; 14%) for the humerus and structural complication (6 out of 86; 7%) for the femur/tibia. Comparative studies reported mixed results, although the majority (7 out of 11; 64%) reported no significant differences in clinical or radiological outcomes between patients treated with CF or metal plates.

CONCLUSION

This systematic review did not reveal a concerning number of complications related to CF plate fixation. Comparative studies showed no significant differences between CF plates and metal plates for traumatic fracture fixation. Therefore, CF plates appear to be a viable alternative to metal plates. However, high-quality randomized controlled trials (RCTs) with long-term follow-up are strongly recommended to provide additional evidence supporting the use of CF plates.

LEVEL OF EVIDENCE

III, systematic review.

Evaluation of Potential Targets for Fluorescence-Guided Surgery in Pediatric Ewing Sarcoma: A Preclinical Proof-of-Concept Study

Fluorescence-guided surgery (FGS), based on fluorescent tracers binding to tumor-specific biomarkers, could assist surgeons to achieve complete tumor resections. This study evaluated potential biomarkers for FGS in pediatric Ewing sarcoma (ES). Immunohistochemistry (IHC) was performed to assess CD99, CXCR4, CD117, NPY-R-Y1, and IGF-1R expression in ES biopsies and resection specimens. LINGO-1 and GD2 evaluation did not work on the acquired tissue. Based on the immunoreactive scores, anti-CD99 and anti-CD117 were evaluated for binding specificity using flow cytometry and immunofluorescence microscopy. Anti-GD2, a tracer in the developmental phase, was also tested. These three tracers were topically applied to a freshly resected ES tumor and adjacent healthy tissue. IHC demonstrated moderate/strong CD99 and CD117 expression in ES tumor samples, while adjacent healthy tissue had limited expression. Flow cytometry and immunofluorescence microscopy confirmed high CD99 expression, along with low/moderate CD117 and low GD2 expression, in ES cell lines. Topical anti-CD99 and anti-GD2 application on ES tumor showed fluorescence, while anti-CD117 did not show fluorescence for this patient. In conclusion, CD99-targeting tracers hold promise for FGS of ES. CD117 and GD2 tracers could be potential alternatives. The next step towards development of ES-specific FGS tracers could be ex vivo topical application experiments on a large cohort of ES patients.

Immunohistochemical Evaluation of Candidate Biomarkers for Fluorescence-Guided Surgery of Myxofibrosarcoma Using an Objective Scoring Method

INTRODUCTION

Myxofibrosarcoma (MFS) is the most common soft-tissue sarcoma subtype in elderly patients. Local recurrence (LR) remains a major concern as the lack of intraoperative guidance and an infiltrative growth pattern with long, slender tails hamper surgeons' ability to achieve adequate resection margins for MFS. Fluorescence-guided surgery (FGS) could overcome this concern by delineating tumor tissue during surgery. One of the most important steps to successful FGS is to define a tumor-specific biomarker that is highly overexpressed in tumor tissue while low or absent in adjacent healthy tissue. The aim of this study is to evaluate the expression of eight previously selected promising biomarkers for FGS in MFS tissue samples with adjacent healthy tissue using immunohistochemistry (IHC).

METHODS

The following eight biomarkers were stained in seventeen paraffin-embedded MFS samples: tumor endothelial marker-1 (TEM-1, also known as endosialin/CD248), vascular endothelial growth factor receptor-1 (VEGFR-1, also known as Flt-1), vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Flk1), vascular endothelial growth factor-A (VEGF-A), epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), platelet derived growth factor receptor-α (PDGFR-α), and cluster of differentiation 40 (CD40, also known as TNFRSF5). A pathologist specializing in sarcoma annotated the margin between the tumor and adjacent healthy tissue in each MFS tissue sample. Subsequently, we used an objective IHC scoring method to assess and compare the difference in staining intensity between the tumor and adjacent healthy tissue, which is crucial for the use of FGS.

RESULTS

TEM-1, VEGF-A, and PDGFR-α stained all MFS tumors, while the other biomarkers did not show expression in all MFS tumors. Ultimately, TEM-1 was identified as the most suitable biomarker for FGS in MFS based on higher tumor-to-background (TBR) staining intensity compared to VEGF-A and PDGFR-α, regardless of preoperative therapy.

CONCLUSION

TEM-1-targeted FGS tracers should be further investigated to optimize MFS treatment.

Is the Anterior Injection Approach Without Ultrasound Guidance Superior to the Posterior Approach for Adhesive Capsulitis of the Shoulder? A Sequential, Prospective Trial

BACKGROUND

Shoulder injections for conditions such as adhesive capsulitis are commonly performed and can be administered through image-based or landmark-based injection approaches. Ultrasound-guided injections are widely used and accurate because ultrasound allows real-time visualization of the needle and injected contrast. Landmark-based injections would be advantageous, if they were accurate, because they would save the time and expense associated with ultrasound. However, few prospective studies have compared well-described landmark-based shoulder injection techniques without ultrasound.

QUESTION/PURPOSE

Using anatomic landmarks, and without using ultrasound, is the accuracy of glenohumeral injection for adhesive capsulitis greater via the posterior approach or via a new anterior approach?

METHODS

Between 2018 and 2020, we treated 108 patients potentially eligible for adhesive capsulitis treatment. These patients had clinical symptoms of aggravating shoulder pain with a duration of less than 4 months and passively impaired, painful glenohumeral ROM. Due to the exclusion of patients with other shoulder conditions (full-thickness rotator cuff ruptures and posttraumatic stiffness), 95 patients received an injection in this sequential, prospective, comparative study. Between 2018 and 2019, 41 patients (17 males and 24 females; mean age 52 ± 5 years; mean BMI 24 ± 3 kg/m2) were injected through the posterior approach, with the acromion as the anatomical landmark, during the first part of the study period. After that, between 2019 and 2020, 54 patients (20 males and 34 females; mean age 54 ± 4 years; mean BMI 23 ± 3 kg/m2) received an injection through a new anterior approach, with the acromioclavicular joint as the anatomic landmark, during the second part of the study period. Injections via both approaches were administered by two experienced shoulder specialists (both with more than 10 years of experience). Both specialists had experience with the posterior approach before this study, and neither had previous training with the new anterior approach. Injections contained a corticosteroid, local anaesthetic, and contrast medium. Radiographs were taken within 20 minutes after the injection, and a radiologist blinded to the technique determined accuracy. Accurate injections were defined as having contrast fluid limited to the glenohumeral joint, while inaccurate injections displayed leakage of contrast fluid into the soft tissue or subacromial space. All of the enrolled patients were analyzed.

RESULTS

In the group with the posterior approach, the accuracy was 78% (32 of 41) in contrast to 94% (51 of 54, odds ratio 0.21 [95% CI 0.05 to 0.83]; p = 0.03) in patients with the new anterior approach.

CONCLUSION

The new anterior approach without the use of ultrasound was more accurate than the posterior approach. In fact, it was nearly as accurate as previously published ultrasound-guided approaches. We recommend using the new anterior approach for intraarticular glenohumeral injections instead of ultrasound-guided injections because it will save time and costs associated with ultrasound. Still, the clinical effects (anxiety, pain, functional outcome, and adverse events) of the new anterior approach should be compared with ultrasound-guided injections in a randomized study.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Introducing Fluorescence-Guided Surgery for Pediatric Ewing, Osteo-, and Rhabdomyosarcomas: A Literature Review

Sarcomas are a rare heterogeneous group of malignant neoplasms of mesenchymal origin which represent approximately 13% of all cancers in pediatric patients. The most prevalent pediatric bone sarcomas are osteosarcoma (OS) and Ewing sarcoma (ES). Rhabdomyosarcoma (RMS) is the most frequently occurring pediatric soft tissue sarcoma. The median age of OS and ES is approximately 17 years, so this disease is also commonly seen in adults while non-pleiomorphic RMS is rare in the adult population. The mainstay of all treatment regimens is multimodal treatment containing chemotherapy, surgical resection, and sometimes (neo)adjuvant radiotherapy. A clear resection margin improves both local control and overall survival and should be the goal during surgery with a curative intent. Real-time intraoperative fluorescence-guided imaging could facilitate complete resections by visualizing tumor tissue during surgery. This review evaluates whether non-targeted and targeted fluorescence-guided surgery (FGS) could be beneficial for pediatric OS, ES, and RMS patients. Necessities for clinical implementation, current literature, and the positive as well as negative aspects of non-targeted FGS using the NIR dye Indocyanine Green (ICG) were evaluated. In addition, we provide an overview of targets that could potentially be used for FGS in OS, ES, and RMS. Then, due to the time- and cost-efficient translational perspective, we elaborate on the use of antibody-based tracers as well as their disadvantages and alternatives. Finally, we conclude with recommendations for the experiments needed before FGS can be implemented for pediatric OS, ES, and RMS patients.