Comparison of the Results of Delayed Repair of Flexor Pollicis Longus (FPL) Tendon with Tendon Transfer or with Tendon Graft.

Background: In Flexor Pollicis Longus (FPL) injuries, primary repair with end-to-end suture is the treatment of choice. In cases where primary repair is not possible, tendon transfer or tendon grafting is used, each of which has its strengths and weaknesses. We aimed to investigate the effectiveness of each of the above two methods in patients. Methods: Patients with FPL injury who referred to Hazrat Fatemeh Hospital, Tehran, Iran late in 2020 to 2021, if primary tendon repair was not possible, were randomly repaired with tendon transfer or tendon graft. After the appropriate time, the splint was opened and physiotherapy was performed for the patients. Then, at least three months after the repair, the range of motion of the IP and MP joints of the patients thumb was measured and compared in two groups. Results: Ten patients in the tendon transfer group and 10 patients in the tendon graft group were studied. In the secondary repair of FPL with tendon grafting, the range of motion of both IP and MP joints of the thumb was not significantly different compared to repair with tendon transfer. Conclusion: The findings of this research confirm controversies in this field. In order to obtain more accurate results, it is suggested to carry out a research with a larger number of patients and with strict control over the surgical technique and post-operative care, as well as taking into account the morbidities caused by donor tendon removal and examining the overall satisfaction of the patients.

Tenocyte-imprinted substrate: a topography-based inducer for tenogenic differentiation in adipose tissue-derived mesenchymal stem cells.

Tendon tissue engineering based on stem cell differentiation has attracted a great deal of attention in recent years. Previous studies have examined the effect of cell-imprinted polydimethylsiloxane (PDMS) substrate on induction differentiation in stem cells. In this study, we used tenocyte morphology as a positive mold to create a tenocyte-imprinted substrate on PDMS. The morphology and topography of this tenocyte replica on PDMS was evaluated with scanning electron microscopy (SEM) and atomic force microscopy. The tenogenic differentiation induction capacity of the tenocyte replica in adipose tissue-derived mesenchymal stem cells (ADSCs) was then investigated and compared with other groups, including tissue replica (which was produced similarly to the tenocyte replica and was evaluated by SEM), decellularized tendon, and bone morphogenic protein (BMP)-12, as other potential inducers. This comparison gives us an estimate of the ability of tenocyte-imprinted PDMS (called cell replica in the present study) to induce differentiation compared to other inducers. For this reason, ADSCs were divided into five groups, including control, cell replica, tissue replica, decellularized tendon and BMP-12. ADSCs were seeded on each group separately and investigated by the real-time reverse transcription polymerase chain reaction (RT-PCR) technique after seven and 14 days. Our results showed that in spite of the higher effect of the growth factor on tenogenic differentiation, the cell replica can also induce tenocyte marker expression (scleraxis and tenomodulin) in ADSCs. Moreover, the tenogenic differentiation induction capacity of the cell replica was greater than tissue replica. Immunocytochemistry analysis revealed that ADSCs seeding on the cell replica for 14 days led to scleraxis and tenomodulin expression at the protein level. In addition, immunohistochemistry indicated that contrary to the promising results in vitro, there was little difference between ADSCs cultured on tenocyte-imprinted PDMS and untreated ADSCs. The results of such studies could lead to the production of inexpensive cell culture plates or biomaterials that can induce differentiation in stem cells without growth factors or other supplements.

Decellularization and preservation of human skin: A platform for tissue engineering and reconstructive surgery.

A matrix derived from natural tissue functions as a highly biocompatible and versatile scaffold for tissue engineering applications. It can act as a supportive construct that provides a niche for colonization by host cells. In this work, we describe a cost-effective, reliable and reproducible protocol for decellularization and preservation of human skin as a potential soft tissue replacement. The decellularized human skin is achieved using purely chemical agents without any enzymatic steps. The suitability of the proposed method for the preservation of the extracellular matrix (ECM) structure and its main components and integrity were evaluated using histological and immunohistochemical analysis. Cryopreservation and final sterility were conducted using programmable freeze-drying and gamma irradiation. The architecture, basement membrane and 3D structure of ECM can be successfully preserved after decellularization. Our protocol was found to be appropriate to maintain key proteins such as collagen type I, III, IV and laminin in the structure of final scaffold. This protocol offers a novel platform for the preparation of a dermal substitute for potential clinical applications. STATEMENT OF SIGNIFICANCE: Clinical application of naturally-based scaffolds for verity of health problems obliges development of a reproducible and effective technology that does not change structural and compositional material properties during scaffold preparation and preservation. Lack of an effective protocol for the production of biological products using decellularization method is still remaining. This effort is directing to solve this challenge in order to accomplish the off-the -shelf availability of decellularized dermal scaffold in market for clinical application.

Tissue expanders; review of indications, results and outcome during 15 years' experience.

BACKGROUND: Tissue expanders (TE) are frequently used worldwide. In this study we surveyed outcome of our patients retrospectively during 15 years. MATERIALS AND METHODS: We had 1105 patients for whom 3059 TEs have been used. Demographic data, age, sex, indications, type of tissue expander devices, volume of devices, site of scar and site TE insertion, our technique for tissue expander insertion and flap design, complications and outcome were gathered. A complete and through technical points and tips will be discussed. RESULTS: In 91% of patients overexpansion was done. (Expansion ratio=2.1-4.5). Re-expansion has been done in about 12% of patients. Complications were perforation of skin of pocket (11%) or exposure, infection (6%), dehiscence of the wound (1.5%), perforation of the port or disconnection of the tubes (2.1%), expansion of the scar itself (1%), saggy flap (3%), dog ear (5%), lack of adhesions of flap to its new site (4%). OUTCOME: In 93% of the patients we could totally remove the scar. Around 9.1% of our patients had two sessions of expansion in the same area and 2.9% had three sessions of expansion. 51% of our patients were highly satisfied and 42% were satisfied of the results of expansion. CONCLUSION: Our patients were satisfied with the results. In 12% cases we have done re-expansion. Re-expansion is possible as long as you have enough thickness of dermis in the skin. More than 50% of our patients were optimistic for 2nd or 3rd session of re-expansion.

Unilateral Buccinator Flap for Lengthening of Short Palate.

BACKGROUND: Velopharyngeal insufficiency is one of the most frequent complications after cleft palate repair. PURPOSE: To evaluate the results and complications of unilateral Buccinator flap (BMF) in velopharyngeal insufficiency. MATERIALS AND METHODS: During 4 years the authors performed unilateral BMF in all short palates. Age, sex, demographic data, length of palate, cause of short palate, nasopharyngoscopy and videofluroscopy results, hyper nasality, nasal escape, nasal emission, nasal fluid leak, speech evaluation and results, outcome and complications of the treatment were surveyed before surgery and in 1, 3, 6 months after treatment. RESULTS: The authors had 43 patients, 29 below 8 years old and 14 adults. Velopharyngeal gap was between 10 and 27 mm, mean 21 mm. Buccinator flap were measuring 15 to 19 mm in width and 32 to 56 mm in length. The operation time was 80 to 100 minutes, mean 86 minutes.Nasal emission, nasal escape, and nasal leak were treated in all patients.Hyper nasality was completely improved in all of the patients below 8 years old (29 patients) and in 10 patients of the adults (totally 39 patients, 90.6%). And it was improved significantly in other 4 patients (9.4%). The speech evaluation reported between 70% and 86% improvements.The lengthening of the palate was between 12 and 19 mm, mean 17 mm.The satisfaction of the patients was as 0% poor, 2.3% fair, 72.1% good, and 25.6% excellent. CONCLUSION: Unilateral BMF is reliable, promising, and safe flap for lengthening of short palate and it can lengthen the palate up to 19 mm. The time of surgery is very short compared with other methods. It is an anatomical treatment versus pharyngeal flap which is not an anatomical one. Speech improvement will achieve in 70% to 86% patients.

Acceleration of bone regeneration in bioactive glass/gelatin composite scaffolds seeded with bone marrow-derived mesenchymal stem cells over-expressing bone morphogenetic protein-7.

In this research, the osteoinduction effect of a novel variant of bone morphogenetic protein-7 (BMP-7), delivered through bone marrow mesenchymal stem cells (BM-MSCs) seeded on bioactive glass/gelatin nanocomposite scaffolds, was evaluated in a calvarial critical size defect in rats. After being harvested and characterized in vitro, BM-MSCs were infected by a plasmid vector containing BMP-7 encoding gene enriched with a heparin-binding site (B2BMP-7) to assess its osteogenic effects in vivo. The animals were randomly categorized into three groups receiving the scaffold alone (group I), the scaffold seeded with BM-MSCs (group II), and the scaffold seeded with manipulated BM-MSCs (group III). After 2, 4 and 12 postoperative weeks, the animals were sacrificed and the harvested specimens were analyzed using histological and immunohistochemical staining. The results of in vitro tests (preliminary screening) showed that the synthesized scaffolds were biocompatible constructs supporting cell attachment and expansion. The in vivo results revealed higher osteogenesis in the defects filled with the B2BMP-7 excreting BM-MSCs/scaffolds compared to the other two groups. After 12weeks of implantation, fully mature newly formed bone was detected throughout the damaged site, which indicates a synergistic effect of cells, scaffolds and growth factors in the process of tissue regeneration. Therefore, bioactive glass-containing scaffolds pre-seeded with manipulated BM-MSCs exhibit an effective combination to improve osteogenesis in bone defects, and the approach followed in this work could have a significant impact in the development of novel tissue engineering constructs.