Rapid printing of 3D porous scaffolds for breast reconstruction

Prosthesis implantation and fat transplantation are common breast reconstructionmethods.In general,prosthesis implantation alone does not achieve a realistic enough appearance,and fat transplantation alone is difficult to achieve in the correct capacity.To date,no reports have focused on methods of combining fat with implanted prostheses for breast reconstruction.Using a newly designed bionic ink(i.e.,polyether F127 diacrylate(F127DA)&poly(ethylene glycol)diacrylate(PEGDA))and projection-based three-dimensional bioprinting(PBP),we report the development of a new method for printing porous prostheses.PEGDA was used to improve the printing precision of the prosthesis by increasing the gel point of F127DA and reducing the impact of external temperature.The compression modulus of the printed prosthesis was very close to that of prostheses currently used in clinical practice and to that of natural breasts.Finally,stromal vascular fraction gel(SVF-gel),a human fat extract,was injected into the pores of the synthesized prostheses to prepare a prosthesis mixed with adipose tissue.These were implanted subcutaneously in nude mice to observe their biological performance.After 14 and 28 days of observation,the prosthesis showed good biocompatibility,and adipose tissues grew well in and around the prosthesis.This result shows that a porous prosthesis containing pre-placed adipose tissues is a promising breast reconstruction material.

Facial Merkel cell carcinoma in a patient with diabetes and hepatitis B:A case report

BACKGROUND Patients with chronic inflammatory disorders are at a higher risk of developing aggressive Merkel cell carcinoma(MCC). Diabetes is a common chronic inflammatory disease that is possibly associated with MCC;however, there are still no reports on the association between hepatitis B virus(HBV) infection and MCC. Whether there is an association between these three diseases and the specific mechanisms behind their effects is worth further research in the future.CASE SUMMARY We herein report a rare case of MCC with extracutaneous and nodal invasion in an Asian individual with type 2 diabetes mellitus and chronic HBV infection, but no immunosuppression or other malignancies. Such cases are uncommon and have rarely been reported in the literature. A 56-year-old Asian male presented with a significant mass on his right cheek and underwent extensive resection combined with parotidectomy, neck lymphadenectomy, and split-thickness skin grafting. Based on the histopathological findings, a diagnosis of MCC involving the adipose tissue, muscle, nerve, and parotid gland with lymphovascular invasion was made. Subsequently, he received radiotherapy with no adverse reactions.CONCLUSION MCC is a rare, aggressive skin cancer with frequent local recurrence, nodal invasion, and metastasis, which usually arises in older people of the white race. Patients with chronic inflammatory disorders are at a higher risk of developing aggressive MCC. The diagnosis can be confirmed with histology and immunohistochemistry. For localized MCC, surgery is the preferred treatment option. However, for advanced MCC, radiotherapy and chemotherapy have proven to be effective. In cases where chemotherapy is not effective or in the advanced stages of MCC, immune therapy plays an important role in treatment. As with any rare disease, the management of MCC remains an enormous challenge for clinicians;thus, follow-up should be individualized and future progress needs multidisciplinary collaborative efforts. Furthermore, physicians should include MCC in their list of possible diagnoses when they come across painless, rapidly growing lesions, particularly in patients with chronic HBV infection or diabetes, as these patients are more susceptible to the development of this condition and it tends to be more aggressive in them.

Pneumomediastinum and subcutaneous emphysema secondary to dental extraction:Two case reports

BACKGROUND Dental extraction is a common operation in oral surgery and is usually accompanied by pain,swelling,and local infection.The application of high-speed air turbines increases the comfort of alveolar surgery and makes it more minimally-invasive.However,high-speed gas can enter the subcutaneous tissue of the face and neck or even the chest and mediastinum,which is a serious iatrogenic complication.CASE SUMMARY We describe two cases of severe subcutaneous and mediastinal emphysema caused by high-speed turbine splitting during dental extraction.The first case involved a 34-year-old man who complained of swelling of the face,mild chest tightness,and chest pain after dental extraction.Computed tomography(CT)scan showed a large amount of gas in the neck,chest wall,and mediastinum.The second case involved a 54-year-old woman who complained of swelling and pain of the neck after dental extraction.CT showed a large amount of gas collected in the neck and mediastinum.Both of them used high-speed turbine splitting during dental extraction.CONCLUSION High-speed turbine splitting during dental extraction may lead to severe subcutaneous and mediastinal emphysema.Dentists should carefully operate to avoid emphysema.If emphysema occurs,CT can be used to improve the diagnosis.The patient should be informed,and the complications dealt with carefully.

Modified membrane fixation technique in a severe continuous horizontal bone defect:A case report

BACKGROUND Continuous severe horizontal bone defect is common in the aesthetic maxillary anterior area,and presents a major challenge in implant dentistry and requires predictable bone augmentation to increase the width of the alveolar bone.CASE SUMMARY A 24-year-old man,with a history of well-controlled IgA nephropathy,presented to the Dentistry Department of our hospital complaining of missing his right maxillary anterior teeth 1 mo ago.Severe horizontal alveolar bone defects at sites of teeth 12,13 and 14 were diagnosed.A modified guided bone regeneration surgical approach stabilizing the absorbable collagen membrane and particulate graft materials by periosteal diagonal mattress suture(PDMS)combined with four corner pins was used for this severe continuous horizontal bone defect.The outcome revealed that the newly formed alveolar ridge dimension increased from 0.72 mm to 11.55 mm horizontally 10 mo postoperatively,with no adverse events.The implant surgery was successfully performed.CONCLUSION This case highlights that PDMS combined with four corner pins is feasible to maintain the space and stabilize the graft and membranes in severe continuous horizontal bone defect.

Tumor-like disorder of the brachial plexus region in a patient with hemophilia:A case report

BACKGROUND Various tumors and tumor-like disorders,originating from the neural sheath,as well as other types,may affect the brachial plexus region.Due to the infrequent presentation,brachial plexus palsy caused by spontaneous hematoma in patients with hemophilia might miss the treatment by early surgical decompression and progress to permanent nerve damage.CASE SUMMARY The case reported here was a 30-year-old man with hemophilia,as well as both sensory and motor dysfunction of the left upper extremity.A presumptive diagnosis of brachial plexus tumor was initially made,which was subsequently confirmed to be an organized chronic hematoma rather than a neoplasm.The hemophilia-induced expanding hematoma compressing the brachial plexus was considered to be the main reason for the patient’s complaints.The clinical symptoms were alleviated and the involved nerves partially recovered at a follow-up of 1 year.CONCLUSION Early surgical intervention is crucial and it seems to be an essential precondition for recovery of nerve function in brachial plexus lesions.