Biodegradable inflatable balloons for tissue separation

Assessment of Bioprotect's Biodegradable Balloon System as a Rectal Spacer in Radiotherapy: An Animal Study on Tissue Response and Biocompatibility

Prostate cancer is a significant health concern for men, emphasizing the need for effective treatment strategies. Dose-escalated external beam radiotherapy shows promise in improving outcomes but presents challenges due to radiation effects on nearby structures, such as the rectum. Innovative techniques, including rectal spacers, have emerged to mitigate these effects. This study comprehensively assessed tissue responses following the implantation of the Bioprotect biodegradable fillable balloon as a rectal spacer in a rat model. Evaluation occurred at multiple time points (4, 26, and 52 weeks) post-implantation. Results revealed localized tissue responses consistent with the expected reaction to biodegradable materials, characterized by mild to moderate fibrotic reactions and encapsulation, underscoring the safety and biocompatibility of the balloon. Importantly, no other adverse events occurred, and the animals remained healthy throughout the study. These findings support its potential clinical utility in radiotherapy treatments to enhance patient outcomes and minimize long-term implant-related complications, serving as a benchmark for future similar studies and offering valuable insights for researchers in the field. In conclusion, the findings from this study highlight the safety, biocompatibility, and potential clinical applicability of the Bioprotect biodegradable fillable balloon as a promising rectal spacer in mitigating radiation-induced complications during prostate cancer radiotherapy.

Poly-l-lactide-co-ε-caprolactone (PLCL) and poly-l-lactic acid (PLLA)/gelatin electrospun subacromial spacer improves extracellular matrix (ECM) deposition for the potential treatment of irreparable rotator cuff tears

Biodegradable subacromial spacer implantation has become practicable for the treatment of irreparable rotator cuff tears (IRCT). However, the relative high degradation rate and inferior tissue regeneration properties of current subacromial spacer may lead to failure regards to long-term survival. It is reported that satisfactory clinical results lie in the surrounding extracellular matrix (ECM) deposition after implantation. This study aims to develop a biological subacromial spacer that would enhance tissue regeneration properties and results in better ECM deposition. Physicochemical properties were characterized on both poly-l-lactide-co-ε-caprolactone (PLCL) dip-coating spacer (monolayer spacer, MS) and PLCL dip-coating + Poly-l-Lactic Acid (PLLA)/Gelatin electrospun spacer (Bilayer Spacer, BS). Cytocompatibility, angiogenesis, and collagen inducibility were evaluated with tendon fibroblasts and endothelial cells. Ultrasonography and histomorphology were used to analyze biodegradability and surrounding ECM deposition after the implantation in vivo. BS was successfully fabricated with the dip-coating and electrospinning technique, based on the human humeral head data. In vitro studies demonstrated that BS showed a greater cytocompatibility, and increased secretion of ECM proteins comparing to MS. In vivo studies indicated that BS promoted ECM deposition and angiogenesis in the surrounding tissue. Our research highlights that BS exhibits better ECM deposition and reveals a potential candidate for the treatment of IRCT in future.

Subacromial balloon spacer - Where are we now?

INTRODUCTION

Rotator cuff tears are a common cause of disability and pain. The ideal treatment for truly irreparable rotator cuffs is still debated, and one recent surgical advance is the development of the subacromial balloon spacer. This review aims to clarify the current evidence and indications for this device.

METHODS

A comprehensive literature search was undertaken using the MeSH search terms combining "balloon spacer" and "irreparable cuff tear". A total of 20 studies using the balloon spacer as a treatment modality in more than two patients, were analysed.

RESULTS

A total of 513 patients were analysed, representing 83% of those initially identified as meeting the inclusion criteria. The majority of studies recommended the device, with only four suggesting it was not recommended based on their results. Notable bias was present in the studies analysed, and there were no papers providing greater than level III evidence.

CONCLUSION

The subacromial balloon spacer is one possible treatment option for older, low-demand patients with a full thickness rotator cuff tear involving only the supraspinatus tendon, who also have no arthritis and have preserved active elevation beyond 90°. However, the results of two large randomised prospective trials are awaited to provide satisfactory evidence regarding the use of the balloon spacer.

Effect of Ethylene Oxide and Gamma (γ-) Sterilization on the Properties of a PLCL Polymer Material in Balloon Implants

Poly-l-lactide-co-ε-caprolactone (PLCL) is a unique polymer containing both polylactic acid and poly-ε-caprolactone (PCL) chain units, and thus it has better flexible and biodegradable properties. Based on these unique properties of PLCL, we have developed balloons that are now widely used in treating major medical problems [Biomaterials 2016, 105, 109-116]. One of the most important considerations needed for balloons is to ensure that the material properties remain similar after undergoing ethylene oxide (EtO) or gamma (γ-) sterilization treatments. From the biotechnological point of view, we focused on analyzing the vital molecular properties of the PLCL material after sterilization, such as changes in crystallinity, molecular weight distributions (M _w, M _n, and polydispersity index), and inherent viscosity (η). Analysis of the data reveals that EtO sterilization does not engender any change in crystallinity, melting temperature (T _m), molecular weights, and η of the polymer. On the contrary, γ-radiations induce chain scission and consequential decrease of ∼33 and ∼15% in molecular weights and η values, respectively. Based on our observations, we recommend EtO sterilization instead of γ-radiation for PLCL. This ensures prolonged stability of the polymer against degradation in a biological environment, long-shelf life, and absolute assurance that balloon failures do not occur after implantation.

Biodegradable implantable balloons: Mechanical stability under physiological conditions

Rotator cuff tendons injuries occurs as a result of trauma, e.g. due to falling, mechanical injuries and frequent overhead activity and as natural degenerative tears in elderly people. Biodegradable balloon shaped spacer of Poly-(L-lactide-co-ε-caprolactone) (PLCL) are applied in the treatment of these injuries. This type of treatment involves insertion of inflated biodegradable implant into the tissues of the damaged region in the shoulder to avoid shoulder impingement and reduce friction between the acromion and the humeral head and propagation of inflammation. The implant must maintain integrity under significant mechanical loading in order to remain effective. However, with time, the implant is exposed to the risk of failure due to the high pressure caused by the muscular motion and the friction with the bones. We report in this study the limits of the mechanical stability of the PLCL balloon shape spacer (implant) under prolonged cyclic loading, so as to be able to predict their physical stability in vivo. We have demonstrated in an in vitro settings that the implant withstands fatigue cycles for significantly longer than 8 weeks, which provides sufficient time window for patients to perform substantial rehabilitation and recover from an injury. The data presented herein is expected to assist medical practitioners in safety and efficacy measurements and assessment following spacer implantation.