3D-printed vertebral body for anterior spinal reconstruction in patients with thoracolumbar spinal tumors

Applying 3D-printed prostheses to reconstruct critical-sized bone defects of tibial diaphysis (> 10 cm) caused by osteomyelitis and aseptic non-union

BACKGROUND

Clinical repair of critical-sized bone defects (CBDs) in the tibial diaphysis presents numerous challenges, including inadequate soft tissue coverage, limited blood supply, high load-bearing demands, and potential deformities. This study aimed to investigate the clinical feasibility and efficacy of employing 3D-printed prostheses for repairing CBDs exceeding 10 cm in the tibial diaphysis.

METHODS

This retrospective study included 14 patients (11 males and 3 females) with an average age of 46.0 years. The etiologies of CBDs comprised chronic osteomyelitis (10 cases) and aseptic non-union (4 cases), with an average defect length of 16.9 cm. All patients underwent a two-stage surgical approach: (1) debridement, osteotomy, and cement spacer implantation; and (2) insertion of 3D-printed prostheses. The interval between the two stages ranged from 8 to 12 weeks, during which the 3D-printed prostheses and induced membranes were meticulously prepared. Subsequent to surgery, patients engaged in weight-bearing and functional exercises under specialized supervision. Follow-up assessments, including gross observation, imaging examinations, and administration of the Lower Extremity Functional Scale (LEFS), were conducted at 3, 6, and 12 months postoperatively, followed by annual evaluations thereafter.

RESULTS

The mean postoperative follow-up duration was 28.4 months, with an average waiting period between prosthesis implantation and weight-bearing of 10.4 days. At the latest follow-up, all patients demonstrated autonomous ambulation without assistance, and their LEFS scores exhibited a significant improvement compared to preoperative values (30.7 vs. 53.1, P < 0.001). Imaging assessments revealed progressive bone regeneration at the defect site, with new bone formation extending along the prosthesis. Complications included interlocking screw breakage in two patients, interlocking screw loosening in one patient, and nail breakage in another.

CONCLUSIONS

Utilization of 3D-printed prostheses facilitates prompt restoration of CBDs in the tibial diaphysis, enabling early initiation of weight-bearing activities and recovery of ambulatory function. This efficacious surgical approach holds promise for practical application.

Comparison of En Bloc Resection and Intralesional Excision for Re-resection of Giant Cell Tumors of the Spine

OBJECTIVE

Re-resection of spinal giant cell tumors is an exceedingly difficult procedure. Moreover, the prognosis of patients with en bloc resection or intralesional excision for re-resection has rarely been reported. This study aimed to compare the prognostic value of en bloc resection with that of intralesional excision in patients undergoing re-resection for giant cell tumors of the spine.

METHODS

This retrospective analysis evaluated patients who underwent revision surgeries for relapse of giant cell tumors of the spine at our center between January 2005 and January 2021. Local progression-free survival represents the duration between en bloc resection or intralesional excision and tumor recurrence. Neurological recovery, survival rates, local control, and complications were evaluated. The Kaplan-Meier estimator was used for survival analysis.

RESULTS

A total of 22 patients (nine men and 13 women) with a mean age of 34.1 (range 19-63) years were included. Significant statistical differences were found in the local tumor recurrence rate between patients treated with en bloc resection and those treated with intralesional excision (p < 0.05). The 5- and 10-year local progression-free survival rates were both 90% in the en bloc resection group, while in the intralesional excision group, the 5-year local progression-free survival rate was 80% with a 10-year rate of 45.7%. The en bloc resection group had a lower local tumor recurrence rate than that of the intralesional excision group (p < 0.05), but the former had a higher rate of complications (p = 0.015).

CONCLUSIONS

This study revealed a low local recurrence rate in patients who underwent en bloc resection for giant cell tumors, while the perioperative complication rate was high.

Simvastatin/hydrogel-loaded 3D-printed titanium alloy scaffolds suppress osteosarcoma via TF/NOX2-associated ferroptosis while repairing bone defects

Postoperative anatomical reconstruction and prevention of local recurrence after tumor resection are two vital clinical challenges in osteosarcoma treatment. A three-dimensional (3D)-printed porous Ti6Al4V scaffold (3DTi) is an ideal material for reconstructing critical bone defects with numerous advantages over traditional implants, including a lower elasticity modulus, stronger bone-implant interlock, and larger drug-loading space. Simvastatin is a multitarget drug with anti-tumor and osteogenic potential; however, its efficiency is unsatisfactory when delivered systematically. Here, simvastatin was loaded into a 3DTi using a thermosensitive poly (lactic-co-glycolic) acid (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel as a carrier to exert anti-osteosarcoma and osteogenic effects. Newly constructed simvastatin/hydrogel-loaded 3DTi (Sim-3DTi) was comprehensively appraised, and its newfound anti-osteosarcoma mechanism was explained. Specifically, in a bone defect model of rabbit condyles, Sim-3DTi exhibited enhanced osteogenesis, bone in-growth, and osseointegration compared with 3DTi alone, with greater bone morphogenetic protein 2 expression. In our nude mice model, simvastatin loading reduced tumor volume by 59%-77 % without organic damage, implying good anti-osteosarcoma activity and biosafety. Furthermore, Sim-3DTi induced ferroptosis by upregulating transferrin and nicotinamide adenine dinucleotide phosphate oxidase 2 levels in osteosarcoma both in vivo and in vitro. Sim-3DTi is a promising osteogenic bone substitute for osteosarcoma-related bone defects, with a ferroptosis-mediated anti-osteosarcoma effect.

Comparison of clinical efficacy of 3D-printed artificial vertebral body and conventional titanium mesh cage in spinal reconstruction after total en bloc spondylectomy for spinal tumors: a systematic review and meta-analysis

Propose

This meta-analysis aimed to determine whether 3D-printed artificial vertebral bodies (AVBs) have superior clinical efficacy compared to conventional titanium mesh cages (TMCs) for spinal reconstruction after total en bloc spondylectomy (TES) for spinal tumors.

Methods

Electronic databases, including PubMed, OVID, ScienceDirect, Embase, CINAHL, Web of Science, Cochrane Library, WANFANG, and CNKI, were searched to identify clinical trials investigating 3D-printed AVB versus conventional TMC from inception to August 2023. Data on the operation time, intraoperative blood loss, preoperative and postoperative visual analogue scale (VAS) scores, preoperative and postoperative Frankel classification of spinal cord injury, vertebral body subsidence, and early complications were collected from eligible studies for a meta-analysis. Data were analyzed using Review Manager 5.4 and Stata 14.0.

Results

Nine studies assessing 374 patients were included. The results revealed significant differences between the 3D-printed AVB and conventional TMC groups with regard to operation time (P = 0.04), intraoperative blood loss (P = 0.004), postoperative VAS score (P = 0.02), vertebral body subsidence (P < 0.0001), and early complications (P = 0.02). Conversely, the remaining preoperative VAS score and Frankel classifications (pre-and postoperative) did not differ significantly between the groups.

Conclusion

The 3D-printed AVB in spinal reconstruction after TES for spinal tumors has the advantages of a short operative time, little intraoperative blood loss, weak postoperative pain, low occurrence of vertebral body subsidence and early complications, and a significant curative effect. This could provide a strong basis for physicians to make clinical decisions.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023441521, identifier CRD42023441521.

Surgical outcomes and risk factors for surgical complications after en bloc resection following reconstruction with 3D-printed artificial vertebral body for thoracolumbar tumors

BACKGROUND

The outcomes of patients with tumors of the thoracolumbar spine treated with en bloc resection (EBR) using three-dimensional (3D)-printed endoprostheses are underreported.

METHODS

We retrospectively evaluated patients with thoracolumbar tumors who underwent surgery at our institution. Logistic regression analysis was performed to identify the potential risk factors for surgical complications. Nomograms to predict complications were constructed and validated.

RESULTS

A total of 53 patients with spinal tumors underwent EBR at our hospital; of these, 2 were lost to follow-up, 45 underwent total en bloc spondylectomy, and 6 were treated with sagittal en bloc spondylectomy. The anterior reconstruction materials included a customized 3D-printed artificial vertebral body (AVB) in 10 cases and an off-the-shelf 3D-printed AVB in 41 cases, and prosthesis mismatch occurred in 2 patients reconstructed with the off-the-shelf 3D-printed AVB. The median follow-up period was 21 months (range, 7-57 months). Three patients experienced local recurrence, and 5 patients died at the final follow-up. A total of 50 perioperative complications were encountered in 29 patients, including 25 major and 25 minor complications. Instrumentation failure occurred in 1 patient, and no prosthesis subsidence was observed. Using a combined surgical approach was a dependent predictor of overall complications, while Karnofsky performance status score, lumbar spine lesion, and intraoperative blood loss ≥ 2000 mL were predictors of major complications. Nomograms for the overall and major complications were constructed using these factors, with C-indices of 0.850 and 0.891, respectively.

CONCLUSIONS

EBR is essential for the management of thoracolumbar tumors; however, EBR has a steep learning curve and a high complication rate. A 3D-printed AVB is an effective and feasible reconstruction option for patients treated with EBR.

Reconstruction after resection of C2 vertebral tumors: A comparative study of 3D-printed vertebral body versus titanium mesh

Background

Surgical resection of C2 vertebral tumors is challenging owing to the complex anatomy of C2 vertebrae and the challenges to surgical exposure. Various surgical approaches are available, but some are associated with excessively high risks of complications. An additional challenge is reconstruction of the upper cervical spine following surgery. In the last decade, additive-manufacturing personalized artificial vertebral bodies (AVBs) have been introduced for the repair of large, irregular bony defects; however, their use and efficacy in upper cervical surgery have not been well addressed. Therefore, in this study, we compared instrumented fixation status between patients who underwent conventional titanium mesh reconstruction and those who underwent the same resection but with personalized AVBs.

Methods

We performed a retrospective comparative study and recruited a single-institution cohort of patients with C2 vertebral tumors. Clinical data and imaging findings were reviewed. Through data processing and comparative analysis, we described and discussed the feasibility and safety of surgical resection and the outcomes of hardware implants. The primary outcome of this study was instrumented fixation status.

Results

The 31 recruited patients were divided into two groups. There were 13 patients in group A who underwent conventional titanium mesh reconstruction and 18 group B patients who underwent personalized AVBs. All patients underwent staged posterior and anterior surgical procedures. In the cohort, 9.7% achieved total en bloc resection of the tumor, while gross total resection was achieved in the remaining 90.3%. The perioperative complication and mortality rates were 45.2% and 6.5%, respectively. The occurrence of perioperative complications was related to the choice of anterior approach (p < 0.05). Group A had a higher complication rate than group B (p < 0.05). Four patients (4/13, 30.8%) developed hardware problems during the follow-up period; however, this rate was marginally higher than that of group B (1/18, 5.6%).

Conclusions

Total resection of C2 vertebral tumors was associated with a high risk of perioperative complications. The staged posterior and retropharyngeal approaches are better surgical strategies for C2 tumors. Personalized AVBs can provide a reliable reconstruction outcome, yet minor pitfalls remain that call for further modification.