"Advances in the surgical management of bone tumors"

Comparison of Reconstruction Techniques Following Sacroiliac Tumor Resection: A Systematic Review

BACKGROUND

Although internal hemipelvectomies with sacroiliac resections are not traditionally reconstructed, surgeons are increasingly pursuing pelvic ring reconstruction to theoretically improve stability, function, and early ambulation. This study aims to systematically compare complications and functional and oncologic outcomes of sacroiliac resection with and without reconstruction.

METHODS

PubMed and MEDLINE were queried for studies published between January 1990 and October 2020 pertaining to sacroiliac neoplasm resection with subsequent reconstruction. Patient demographics, histopathologic diagnoses, reconstruction techniques, Musculoskeletal Tumor Society (MSTS) functional scores, and oncologic outcomes were pooled.

RESULTS

Twenty-three studies (201 patients) were included for analysis. Reconstruction was performed in 79.1% of patients, most commonly with nonvascularized autografts (45.8%). The overall complication rate was 54.8%; however, resection followed by reconstruction demonstrated significantly higher complication (62.3% versus 25.7%, p < 0.001) and infection rates (13.7% versus 0%, p = 0.020). Mean MSTS functional score trended higher in nonreconstructed patients (82% versus 71.6%).

CONCLUSIONS

Reconstruction after sacroiliac resection produced higher complication rates and poorer physical recovery when compared with nonreconstructed resection. This systematic review suggests that patients without spinopelvic junction instability may experience superior outcomes without reconstruction. Ultimately, the need to reconstruct the pelvic girdle depends on tumor size, prognosis, and functional goals.

A Dynamic Systems Study on Complexity, Accuracy, and Fluency in English Writing Development by Chinese University Students

This study investigated the development of lexical complexity, sentence complexity, accuracy, and fluency in the English writing of 22 Chinese university students from the perspective of Complex Dynamic Systems Theory (CDST). Compositions were assigned 30 times over the course of one academic year through Pigaiwang, an online platform that automatically evaluates writing. A modified retrodictive modeling approach was adopted. Specifically, a longitudinal cluster analysis was used to examine emergent prototypes. A moving correlation analysis and retrodictive interviews were conducted to study the signature dynamics that produce each prototype. At each collection, the 22 student compositions were classified into two clusters. One cluster contained those students who performed better than average in accuracy, but worse in the other three variables. The other cluster comprised those students with the opposite performance. Students moved continuously between the two clusters; and their change trajectories can be categorized into three prototypes: a continuously stable type, an initially variable and then stable type, and a continuously variable type. Case studies of three students representing the three emergent prototypes indicated that the signature dynamics for the three prototypes were related to dynamic interactions among different variables and dynamic changes in affect-related elements in the form of writing interests, motivation, and strategies. The initial conditions and the feedback from Pigaiwang acted as key control parameters in shaping the prototypes. The continuously variable prototype developed their writing proficiency to the greatest extent and had the most variability. Based upon the findings, implications for teaching L2 writing are discussed.

Enhancing Syntactic Complexity in L2 Chinese Writing: Effects of Form-Focused Instruction on the Chinese Topic Chain

Syntactic complexity, as one aspect of the Complexity, Accuracy and Fluency (CAF) model, is integral to the writing ability of second language (L2) learners. Previous research found that T-unit-based measures of syntactic complexity in writing tasks of English as a second language (ESL) learners increased with more instruction, yet it remains unclear whether the same can be observed in Chinese as a second language (CSL) learners. To fill this gap, this study compared the development of syntactic complexity of a training group (N = 64) and a control group (N = 51), both composed of CSL students in a first-year Chinese course at a university in North America. While participants in the control group only participated in the regular course, the training group received an additional 10-week, explicit form-focused instruction (FFI) on the Chinese topic chain. Results on the posttest and delayed posttest show that the FFI on the topic chain had a positive and durable effect on the participants' syntactic complexity; instructional intensity and feedback type may have influenced its effectiveness and durability. Characteristics of measures and task complexity may have affected the observation of syntactic complexity.

Adjuvant therapy by high-speed burr may cause intraoperative bone tumor seeding: an animal study

Background

Bone tumors are often treated with intralesional curettage. High-speed burring, an adjuvant therapy, was performed to maximize the tumor cell killing; however, tumor recurrence might still occur, which may be caused by residual tumor or local tumor spread during surgery.

Methods

A porcine cadaver (femur) was utilized to determine whether the use of a high-speed burr causes bone cement spray. To mimic residual tumor after curettage, luminescent cement was smeared on two locations of the bone cavity, the wall and the bottom. The cavity in the femoral bone was then placed in the middle of a sheet of drawing paper featuring 10 cm, 20 cm, and 30 cm concentric circles. The luminescent cement was then burred totally with a high-speed burr.

Results

The intensity of the area in the wall in circle I was 72.6% ± 5.8%; within circle II, it was 22.1% ± 4.2%; and within circle III, it was 5.4% ± 1.5%. The intensity of the area within the bottom of the femoral bone within circle I was 66.5% ± 6.1%, within circle II was 28.1 ± 4.8%, and within circle III, it was 5.4% ± 1.4%. The amount of luminescent cement seeding decreased with distance, but there was no difference while burring at different locations of the bone cavity. Under the handpiece cover, a greater amount of cement spray was retained in circle I during burring of the cement in the bottom of the cavity and less was sprayed out in circle III.

Conclusions

High-speed burring may cause explosive bone cement spray, which could extend to 20 cm. The intensities of spray did not decrease, even when the handpiece cover was used. The wide range of bone cement spray caused by high-speed burr was inspected in this pilot study, which may lead to tumor seeding.

Level of evidence

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Composite scaffolds of gelatin and gold nanoparticles with tunable size and shape for photothermal cancer therapy

Photothermal therapy (PTT) has been extensively investigated as a promising strategy for cancer therapy. For successful application of this technique, various nanomaterials have been explored as photothermal conversion agents. Gold nanoparticles (AuNPs), especially Au nanorods and Au nanostars, have received much attention for photothermal therapy because of their facile preparation and high photothermal conversion efficiency. Due to the limited accumulation and easy diffusion of free nanoparticles, incorporation of nanoparticles into scaffolds for direct implantation has been demonstrated as an attractive way for cancer therapy applications. In this study, composite porous scaffolds of gelatin and AuNPs were prepared by introducing Au nanorods and Au nanostars with average sizes of around 35.0, 65.0 and 115.0 nm in gelatin scaffolds. The composite scaffolds were used for the localized PTT application of cancer cells. Gel/AuNP composite scaffolds supported cell adhesion and showed good biocompatibility. Temperature in the composite scaffolds increased quickly upon NIR laser irradiation. Photothermal efficiency and cancer cell killing efficiency were dependent on the shape, size and amount of AuNPs in the composite scaffolds. The composite scaffolds prepared with 65.0 nm Au nanorods showed the highest photothermal efficiency and cell killing efficiency. The results indicated the importance of the shape and size modulation of AuNPs for photothermal therapy applications.

Preparation of gelatin/Fe3O4 composite scaffolds for enhanced and repeatable cancer cell ablation

Various nanomaterials have been extensively investigated for photothermal ablation of cancer cells because of their high photothermal conversion efficiency. However, the poor targeting specificity and low repeated heating efficiency of nanomaterials restrict their applications in the clinic. In this work, porous gelatin/iron oxide (Gel/Fe₃O₄) composite scaffolds were prepared by a facile ice particulate templating method for efficient and repeatable cancer cell ablation. Gel/Fe₃O₄ composite scaffolds showed controlled porous structure consisting of large pores and interconnecting small pores. The strong absorption in the near-infrared (NIR) region enabled the Gel/Fe₃O₄ composite scaffolds to elevate local temperature quickly under NIR laser irradiation. The composite scaffolds allowed cell adhesion and proliferation showing good biocompatibility. Cancer cells entrapped in the scaffolds could be efficiently killed during laser irradiation. Moreover, the therapeutic efficacy of Gel/Fe₃O₄ composite scaffolds could be enhanced by repeated laser irradiation treatment, which is important for clinical application because of the resistant and recurrent nature of cancer. The results indicated that the porous Gel/Fe₃O₄ composite scaffolds had good biocompatibility and excellent cancer cell ablation efficacy, which may provide an attractive way to use porous scaffolds for cancer therapy application.

3D-printed bioceramic scaffolds with a Fe3O4/graphene oxide nanocomposite interface for hyperthermia therapy of bone tumor cells

Magnetic scaffolds display prominent magnetothermal ability, and can effectively kill tumor cells in an alternating magnetic field and improve bone formation ability in vitro.