Biomechanics of the Osseous Pelvis and Its Implication for Consolidative Treatments in Interventional Oncology

Restoring mobility: roles of percutaneous consolidation for pelvic ring bone lesions-a multicenter study

OBJECTIVES

This study aimed to assess the early functional rehabilitation outcomes following percutaneous consolidation for pelvic ring tumor lesions.

MATERIALS AND METHODS

In this multicenter retrospective study, patients with pelvic bone tumor lesions, whether primitive or metastatic, underwent percutaneous consolidation (cementoplasty, screw fixation, or both). The primary outcome was postoperative weight-bearing ambulation. Secondary outcomes included hospitalization duration, procedural complications, and long-term consolidation. Inclusion criteria were patients treated for prophylactic consolidation or pathological fractures. Kaplan-Meier analysis was used for the primary outcome and hospital stay, with p-values < 0.05 indicating significance.

RESULTS

A total of 143 consecutive procedures were performed in 138 patients (mean age, 65 years ± 13; 68 men) who underwent percutaneous screw fixation, cementoplasty, or both. Postoperative weight-bearing ambulation was achieved in 142/143 cases (99%). In total, 117/143 (82%) of these were in the first 24 h. 81/143 (57%) were discharged within 24 h (median, one day; Q3, one day; Q4, 112 days). 133/138 (96.5%) patients achieved long-term consolidation. The most common pattern was isolated acetabular involvement (N = 40; 28%). Of the 19 adverse events, 10 were asymptomatic. Three patients had delayed infections and one required screw removal.

CONCLUSION

Percutaneous consolidation effectively achieved postoperative weight-bearing ambulation and represents a safe and durable treatment option for patients with pelvic bone lesions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT06155890.

KEY POINTS

Question How can radiology continue to help improve care for patients with metastatic pelvic ring lesions? Findings 99% of patients achieved postoperative weight-bearing, with 82% doing so within 24 h. Clinical relevance Percutaneous consolidation enabled rapid functional rehabilitation of oncology patients, allowing short hospital stays with low complication rates, and demonstrating the expanding role of radiologists in diagnosis, risk assessment, and treatment planning, thereby enhancing patient care.

Design and 3D printing of pelvis phantoms for cementoplasty

BACKGROUND

Percutaneous image-guided cementoplasty is a medical procedure for strengthening bones structurally altered by disease, such as osteolytic metastasis. This procedure involves injecting biocompatible liquid bone cement, through one or more trocars into the damaged bone. Within a few minutes the bone cement hardens and restores the rigidity of the bony structure. The introduction of this technique in the case of large cancellous bones, such as the pelvis, raises some practical issues such as: how to manage the flow of cement with variable viscosity over time and how to inject a large amount of cement under fluoroscopy to effectively restore the patient's ability to bear weight?

PURPOSE

As a means of training for young practitioners to ensure maximal filling of a metastatic bone area, we have designed and manufactured a pelvic phantom capable of replicating cement diffusion in healthy and metastatic bone under fluoroscopic and computed tomography guidance.

METHODS

The preliminary stage of the study consisted of an analysis of various lattice structures, with the objective of reproducing the haptic feedback experienced during the needle insertion and diffusion of cement within the trabecular bone. Cementoplasty tests were conducted by an experienced radiologist under fluoroscopy and CT guidance to evaluate the performance of the lattice structure. The initial analysis provided the groundwork for the design of the phantom pelvis, which was then evaluated against a patient case. The phantom was divided into two distinct components: a disposable section with lattice structure, intended for the injection of cement, and a reusable part representing the pelvic bones. Two additive manufacturing methods were selected for the production of the phantom: Stereolithography (SLA) for the lattice structure and Fused Deposition Modeling (FDM) for the pelvic bones. The disposable component was composed of different lattice structures, selected to best match the anatomic conditions of both healthy and diseased areas visible on the patient images. Subsequently, the performance of the phantom was validated against patient images through a cementoplasty test.

RESULTS

A total of 12 distinct lattice structures were subjected to three tests of cementoplasty. Stochastic lattices with 500 microns beam thickness and densities varying from 15% to 5% demonstrated the most effective replication of the needle haptic feedback, as well as the diffusion of the cement into healthy and osteolytic cancellous bone. These structures were then implanted in the phantom and validated against one patient case.

CONCLUSIONS

A methodology to design and manufacture a phantom dedicated to cementoplasty from patient images is proposed. Initially, a series of lattice structures, exhibiting diverse structure types, thicknesses, and densities, were evaluated to assess their capacity to accurately reproduce the haptic feedback of the needle and the diffusion of cement in the trabecular bone. Subsequent to the outcomes of these investigations, several structures were selected for the development of a phantom capable of accurately replicating a cementoplasty procedure under fluoroscopy and CT guidance. This phantom will enable the training of future practitioners on the procedure of cementoplasty in the pelvis.

Outcomes Associated with Functional Mobility and Pain Amelioration in 49 Patients After Sacroplasty: A Single-Center Study

OBJECTIVE

This study aimed to determine the predictive factors for analgesic reduction and amelioration of mobility following percutaneous sacroplasty in patients with insufficiency fractures or metastatic lesions.

METHODS

A single-center retrospective analysis of 49 patients who underwent percutaneous sacroplasty for insufficiency fractures and sacral pathological lesions was conducted. Visual analog scale (VAS), Functional Mobility Scale (FMS), and Oswestry Disability Index (ODI) were assessed. All data were accessed immediately before and 1 month after the procedure.

RESULTS

Thirty-one patients (63.3%) experienced a significant reduction in VAS score, 36 (73.5%) experienced amelioration of FMS, and 20 (40.8%) fell within the ODI at 1 month. The mean VAS score was 7.8 (median [min-max] = 8 [3-10]) preprocedure and 3.4 (median [min-max]=3 [0-8]) postprocedure. The mean ODI was 0.5 (median [min-max]=0.5 [0.3-0.8]) preprocedure and 0.3 (median [min-max]=0.3 [0-0.7]) postprocedure. The mean FMS was 2.6 (median [min-max]=3 [1-5]) preprocedure and 1.2 (median [min-max]=1 [0-4]) postprocedure. There was a statistically significant increase in VAS amelioration in patients without concomitant vertebroplasty (odds ratio=4.16, interval range [1.09; 15.79], P<0.05). Major complications were not observed. In terms of long-term satisfaction, only two patients reported that they would not undergo the same procedure again.

CONCLUSIONS

Percutaneous sacroplasty was effective for pain relief, functional outcomes, and short-term satisfaction. The absence of concomitant vertebroplasty was significantly associated with VAS improvements.

Surgical options for metastatic spine tumors: WFNS spine committee recommendations

Surgical treatments for metastatic spine tumors have evolved tremendously over the last decade. Improvements in immunotherapies and other medical treatments have led to longer life expectancy in cancer patients. This, in turn, has led to an increase in the incidence of metastatic spine tumors. Spine metastases remain the most common type of spine tumor. In this study, we systematically reviewed all available literature on metastatic spine tumors and spinal instability within the last decade. We also performed further systematic reviews on cervical metastatic tumors, thoracolumbar metastatic tumors, and minimally invasive surgery in metastatic spine tumors. Lastly, the results from the systematic reviews were presented to an expert panel at the World Federation of Neurosurgical Societies (WFNS) meeting, and their consensus was also presented.

Initial experience, feasibility, and technical development with an electromagnetic navigation assistance in percutaneous pelvic bone cementoplasty: retrospective analysis

OBJECTIVES

To assess the feasibility and technical outcomes of pelvic bone cementoplasty using an electromagnetic navigation system (EMNS) in standard practice.

MATERIALS AND METHODS

Monocentric retrospective study of all consecutive patients treated with cementoplasty or reinforced cementoplasty of the pelvic bone with EMNS-assisted procedures. The endpoints were periprocedural adverse events, needle repositioning rates, procedure duration, and radiation exposure.

RESULTS

A detailed description of the technical steps is provided. Thirty-three patients (68 years ± 10) were treated between February 2016 and February 2020. Needle repositioning was required for 1/33 patients (3%). The main minor technical adverse event was soft tissue PMMA cement leaks. No major adverse event was noted. The median number of CT acquisitions throughout the procedures was 4 (range: 2 to 8). Radiation exposure and mean procedure duration are provided.

CONCLUSION

Electromagnetic navigation system-assisted percutaneous interventions for the pelvic bone are feasible and lead to low rates of minor technical adverse events and needle repositioning. Procedure duration and radiation exposure were low.

KEY POINTS

• Initial experience for 33 patients treated with an electromagnetic navigation assistance for pelvic cementoplasty shows feasibility and safety. • The use of an electromagnetic navigation system does not expose to high procedure duration or radiation exposure. • The system is efficient in assisting the radiologist for extra-axial planes in challenging approaches.

Combination of Percutaneous Screw Fixation and Cementoplasty for Lytic Bone Metastases: Feasibility, Safety and Clinical Outcomes

OBJECTIVE

To evaluate feasibility, safety and efficacy of a combination of screw fixation and cementoplasty for pathologic bone fracture.

METHODS

In this single-center prospective study, all consecutive percutaneous screw fixations under assisted CT guidance for palliation and fracture treatment of pathologic bone fracture were reviewed from July 2019 to February 2021. The primary outcome measure was the procedures' technical success, defined as the correct placement of the screw(s), without any complications. Secondary outcome measures were the safety, the procedures' early analgesic effects and impacts on quality of life at 4 weeks.

RESULTS

Technical success was achieved in 11/11 procedures (100%) among 11 patients. No major complications attributable to the procedure were noted. The mean pain scored significantly decreased at the initial follow-up: 8.0 ± 2.7 versus 1.6 ± 2.5 (p < 0.05). Opioid doses were statistically lower after procedure: 70.9 ± 37 versus 48.2 ± 46 mg/day (p < 0.05). The mean EQ5D score had significantly increased by the early post-procedure consultation: 42.5 ± 13.6 vs 63.6 ± 10.3 (p < 0.05).

CONCLUSION

Combination of percutaneous screw fixation and cementoplasty for pathologic bone fracture is feasible and safe. It is efficient to reduce pain, decrease the consumption of opioids and improve the quality of life at 4 weeks after the procedure.

Interventional Palliation of Painful Extraspinal Musculoskeletal Metastases

The musculoskeletal system is commonly involved by metastases, and skeletal-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a result of nerve compression often adversely affect patient's quality of life. There have been substantial advances in percutaneous minimally invasive musculoskeletal oncologic interventions for the management of patients with musculoskeletal metastases including thermal ablations, cementation with or without osseous reinforcement via implants, osteosynthesis, neurolysis, and palliative injections which are progressively incorporated in clinical practice. These interventions are performed, in conjunction with or supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesics, to achieve durable pain palliation, local tumor control, or cure. This article reviews minimally invasive percutaneous image-guided musculoskeletal oncologic interventions for the management of patients with extraspinal musculoskeletal metastases.

Reinforced cementoplasty for pelvic tumour lesions and pelvic traumatic fractures: preliminary experience

OBJECTIVES

Pelvic bone pathological lesions and traumatic fractures are a considerable source of pain and disability. In this study, we sought to evaluate the effectiveness of reinforced cementoplasty (RC) in painful and unstable lesions involving the pelvic bone in terms of pain relief and functional recovery.

METHODS

All patients with neoplastic lesion or pelvic fracture for whom a pelvic bone RC was carried out between November 2013 and October 2017 were included in our study. All patients who failed the medical management, patients unsuitable for surgery, and patients with unstable osteolytic lesions were eligible to RC. Clinical outcome was evaluated with a 1-month and 6-month post-procedure follow-up. The primary endpoint was local pain relief measured by the visual analogue scale (VAS).

RESULTS

Twenty-two patients (18 females, 4 males; mean age of 65.4 ± 13.3 years [range 38-80]) presenting with painful and unstable pelvic lesions were treated by RC during the study period. Among the 22 patients, 8 patients presented with unstable pelvic fractures (3 patients with iliac crest fracture, 3 with sacral fractures, and the remaining 2 with peri-acetabular fractures). No procedure-related complications were recorded. All patients had significant pain relief and functional improvement at 1 month. One patient (4.5%) had suffered a secondary fracture due to local tumour progression.

CONCLUSIONS

Reinforced cementoplasty is an original minimally invasive technique that may help in providing pain relief and effective bone stability for neoplastic and traumatic lesions involving the pelvic bone.

KEY POINTS

• Reinforced cementoplasty is feasible in both traumatic fractures and tumoural bone lesions of the pelvis. • Reinforced cementoplasty for pelvic bone lesions provides pain relief and functional recovery. • Recurrence of pelvic bone fracture was observed in 4.5% of the cases in our series.

Pelvis weight-bearing ability after minimally invasive stabilizations for periacetabular lesion

Periacetabular metastatic lesions cause debilitating weight-bearing pain and pose a risk of pelvic pathologic fracture. Minimally invasive percutaneous stabilization is an alternative palliative therapy over extensive open reconstructive surgeries. This study aimed to investigate the biomechanical behaviors of three distinct techniques of percutaneous periacetabular stabilization. A total of 20 composite hemipelves custom-made to contain Harrington type III periacetabular lesion based on a patient's computed tomograpy scans were assigned to treatment groups of cementoplasty alone using polymethyl methacrylate (Cement), screw fixation alone using ischial and posterior-to-anterior screws (Screws), cement-augmented screws (Screws&Cement), and a control group (Untreated). All hemipelves were loaded in a mechanical test configuration mimicking a single-legged stance, and failure load, failure deformation, and construct stiffness were determined. In the experiments, Screws&Cement demonstrated the highest yield strength (4711 ± 362 N) and was 12% higher than Cement (4005 ± 304 N, p = 0.019), 125% higher than Screws (2097 ± 359 N, p < 0.0001), and 184% higher than Untreated (1658 ± 254 N, p < 0.0001). No significant difference in yield strength was found between Screws and Untreated. Screws&Cement also demonstrated the highest stiffness (1013 ± 92 N/mm), followed by Cement (893 ± 49 N/mm), and both groups were significantly stiffer than Screws (543 ± 114 N/mm, p < 0.0001) and Untreated (580 ± 91 N/mm, p < 0.0001 for Screws&Cement, and p = 0.0003 for Cement). This study demonstrated that a cement-augmented periacetabular reconstruction is an effective option for percutaneous treatment of Harrington III periacetabular metastatic lesion. The addition of pelvic screws over cementoplasty significantly improved the pelvis load-bearing strength. When large periacetabular lesions are present, augmented screw fixation appears to be the superior choice of treatment.

Bone Metastases: State of the Art in Minimally Invasive Interventional Oncology

Bone is the third most common site involved by cancer metastases, and skeleton-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a consequence of nerve or spinal cord compression often affect patients' functional independence and quality of life unfavorably. The annual medical-economic burden related to bone metastases is a substantial component of the total direct medical cost estimated by the National Institutes of Health. There have been substantial recent advances in percutaneous image-guided minimally invasive musculoskeletal oncologic interventions for the management of patients with osseous metastatic disease. These advances include thermal ablation, cementation with or without osseous reinforcement with implants, osteosynthesis, thermal and chemical neurolyses, and palliative injections, which are progressively incorporated into the management paradigm for such patients. These interventions are performed in conjunction with or are supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesic agents to achieve durable pain palliation, local tumor control, or cure, and they provide a robust armamentarium for interventional radiologists to achieve safe and effective treatment in a multidisciplinary setting. In addition, these procedures are shifting the patient management paradigm in modern-era practice. The authors detail the state of the art in minimally invasive percutaneous image-guided musculoskeletal oncologic interventions and the role of radiologists in managing patients with skeletal metastases. ^©RSNA, 2021.

Complications of percutaneous image-guided screw fixation: An analysis of 94 consecutive patients

PURPOSE

The purpose of this study was to retrospectively assess the safety profile of percutaneous image-guided screw fixation (PIGSF) for insufficiency, impending or pathological fractures.

MATERIALS AND METHODS

From July 2012 to April 2020, all consecutive patients who underwent PIGSF were retrospectively included in the study. Patient characteristics, fracture type, procedural data and complications were analyzed. Complications were divided into per-procedural, early (<24hours) and delayed (>24hours) and classified into minor (grade 1-2) and major complications (grade 3-5) according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

RESULTS

A total of 110 fractures (40 insufficiency [36%], 53 pathological [48.5%] and 17 impending [15.5%] fractures) in 94 patients (48 women, 46 men; mean age, 62.7±12.7 [SD] years; age range: 32-88 years) were treated with PIGSF during 95 procedures. Twenty-four-hours follow-up was available for all patients, and>24-hours follow-up was available for 79 (79/110; 71.8%) fractures in 69 (69/94; 73.4%) patients. Per-procedural complications occurred in 3/110 fractures (2.7%, all minor). Early complications were reported in 4/110 fractures (3.6%, 1 major and 3 minor) and delayed ones in 14/79 fractures (17.7%, 5 major and 9 minor). The most frequent major delayed complication was infection (3/79; 3.8%).

CONCLUSION

The rate of per-procedural and early (within 24hours) complications following PIGSF is extremely low with most complications being minor, with major complications being delayed ones (>24hours).