Chimeric vs composite flaps for mandible reconstruction

Exosome-loaded hydrogels for craniofacial bone tissue regeneration

It is common for maladies and trauma to cause significant bone deterioration in the craniofacial bone, which can cause patients to experience complications with their appearance and their ability to function. Regarding grafting procedures' complications and disadvantages, the newly emerging field of tissue regeneration has shown promise. Tissue -engineered technologies and their applications in the craniofacial region are increasingly gaining prominence with limited postoperative risk and cost. MSCs-derived exosomes are widely applied in bone tissue engineering to provide cell-free therapies since they not only do not cause immunological rejection in the same way that cells do, but they can also perform a cell-like role. Additionally, the hydrogel system is a family of multipurpose platforms made of cross-linked polymers with considerable water content, outstanding biocompatibility, and tunable physiochemical properties for the efficient delivery of commodities. Therefore, the promising exosome-loaded hydrogels can be designed for craniofacial bone regeneration. This review lists the packaging techniques for exosomes and hydrogel and discusses the development of a biocompatible hydrogel system and its potential for exosome continuous delivery for craniofacial bone healing.

Comparison of Reconstruction of Maxilloalveolar Resections in Head and Neck Cancers with Chimeric Anterolateral Thigh Flap (ALT) versus Standard ALT Flap

Background  Oral malignancy that presents at a locally advanced stage needs complex surgical resections in which the maxillary cavity is usually left open. The constant maxillary secretions lead to problems like poor healing, fistula formation, and flap necrosis, causing longer hospital stays, delayed adjuvant therapy, and additional surgeries. Several methods have been tried to ameliorate this, each faced with its own difficulties. This study describes the use of chimeric free anterolateral thigh (ALT) with vastus lateralis (VL) muscle to tackle this problem. Materials and Methods  With the aim to assess the advantage of reconstruction of maxillo-alveolar resections using chimeric ALT + VL, we analyzed data from 20 cases reconstructed with chimeric free ALT + VL over a year. We compared them with twenty matched controls reconstructed with standard ALT. Analysis was done with respect to intraoperative ease, adequacy of maxillary sinus fill, postoperative secretions, length of hospital stay, duration to adjuvant therapy, and postoperative complications tabulated using the modified Clavien-Dindo classification. Results  It was found that chimeric ALT + VL gave greater freedom of movement to plug the maxillary cavity easily. The chimeric arm patients had fewer complications and a shorter mean hospital stay. Most of them received adjuvant therapy within their optimal time window. Conclusion  Chimeric ALT with vastus lateralis muscle is a reliable option for reconstructing complex defects, especially with dead space cavities like the maxillary sinus. Effective plugging of the maxillary sinus during the primary surgery results in better patient outcomes and must be done routinely.

Virtual surgical planning/3D printing assisted fibula osteoseptocutaneous flap combined with anterolateral thigh flaps for extensive composite oromandibular defects reconstruction: a retrospective study of case series

Oromandibular tumors or osteoradionecrosis often lead to extensive composite defects encompassing intraoral, bone and extraoral tissues. A single flap cannot simultaneously offer sufficient bone and soft tissue. The combination of free flaps could be a prospective approach to overcome the challenge. The study aims to assess the efficacy of virtual surgical planning (VSP) and 3D printing assisted fibula osteoseptocutaneous flap (FOSCF) combined with anterolateral thigh flaps (ALT) in reconstructing extensive composite defects in the oromandibular region. A retrospective analysis was conducted on 8 patients who underwent reconstruction using FOSCFs combined with ALTs. Post-surgical excision of the lesions, we obtained mean values for the defects of intraoral soft tissue, bone, extraoral soft tissue, namely, being 42.7 cm2, 96 mm, and 68.9 cm2. The mean surgical procedures took 712.5 min. A total of 16 flaps were harvested and transplanted for the 8 patients, with all successfully surviving. Postoperatively, complications manifested as localized intraoral infections in 2 cases, intermuscular vein thrombosis in another 2 cases, and pulmonary infections in 2 patients. Two patients unfortunately experienced tumor recurrence, at 12 and 3 months post-operation respectively. For the surviving 6 patients, the average follow-up period was 12.2 months. Regarding patient satisfaction, one expressed dissatisfaction with the contour of the mandible, and two exhibited moderate trismus. Objective assessments identified 1 case of oral incontinence and 2 cases where external flap contractures were observed. All 8 patients experienced restoration of masticatory function and were able to consume a soft diet within a month post-surgery. VSP/3D printing assisted FOSCFs combined with ALTs can be performed safely to reconstruct the extensive composite tissue defects in our study, with desirable esthetic and functional results, and it is a reliable option in selecting patients with defects involving multiple tissue types. However, the benefits of this method needed more cases to validate.

Advanced Hydrogel systems for mandibular reconstruction

Mandibular defect becomes a prevalent maxillofacial disease resulting in mandibular dysfunctions and huge psychological burdens to the patients. Considering the routine presence of oral contaminations and aesthetic restoration of facial structures, the current clinical treatments are however limited, incapable to reconstruct the structural integrity and regeneration, spurring the need for cost-effective mandibular tissue engineering. Hydrogel systems possess great merit for mandibular reconstruction with precise involvement of cells and bioactive factors. In this review, current clinical treatments and distinct mode(s) of mandible formation and pathological resorption are summarized, followed by a review of hydrogel-related mandibular tissue engineering, and an update on the advanced fabrication of hydrogels with improved mechanical property, antibacterial ability, injectable form, and 3D bioprinted hydrogel constructs. The exploration of advanced hydrogel systems will lay down a solid foundation for a bright future with more biocompatible, effective, and personalized treatment in mandibular reconstruction.

[Application of lateral circumflex femoral artery chimeric flap to repair complex wounds of foot and ankle]

OBJECTIVE

To investigate the effectiveness of lateral circumflex femoral artery chimeric flap transplantation in repair of complex wounds of foot and ankle.

METHODS

A retrospective study was conducted to analyze the clinical data of 20 patients with complex wounds of foot and ankle treated with lateral circumflex femoral artery chimeric flap between June 2017 and June 2020. There were 14 males and 6 females with an average age of 42.8 years (range, 21-65 years). Among them, 8 cases had dorsalis pedis tendon defect with or without bone exposure, 4 cases had partial or total Achilles tendon defect without bone exposure, and 8 cases had deep cavity and bone exposure. The wound area ranged from 10 cm×6 cm to 21 cm×11 cm. The time from injury to operation ranged from 6 to 22 days, with an average of 9.4 days. The lateral femoral circumflex artery flap was used in 6 cases with fascia lata flap, 6 cases with rectus femoris aponeurosis flap, and 8 cases with lateral femoral muscle flap. The flap area ranged from 12.0 cm×6.5 cm to 35.0 cm×7.5 cm. All flap donor sites were sutured directly. The survival, appearance, texture, sensation of the flap, and complications of the donor site were observed. The foot and ankle function was evaluated by Kofoed score.

RESULTS

All patients were followed up 8-24 months (mean, 14.2 months). On the 3rd day after operation, 1 case had partial necrosis of 1 flap with fascia lata flap and healed after dressing change; 1 case of chimeric muscle flap developed venous crisis at 12 hours after operation; the chimeric flaps survived successfully in the other 18 patients and the wounds were primary healing. The color and texture of the flaps were good, the flaps recovered protective sensation. Only linear scar remained in the donor site of thigh. There was no sensory disturbance around the incision or walking disturbance. The Kofoed score of the foot and ankle function at last follow-up was 75-96, with an average of 89.8. Among them, 15 cases were excellent, 4 cases were good, and 1 case was qualified. The excellent and good rate was 95.0%.

CONCLUSION

The application of lateral circumflex femoral artery chimeric flap can accurately and stereoscopically repair the complex wounds of foot and ankle and achieve satisfactory effectiveness.

New Chimeric Groin Flap: Experimental Model in Rats

AIM

Increased emphasis is on using tissue substitutes and stem cells to improve flap applicability and survival rates. To accomplish this, the first step is to have a versatile experimental flap, easy to harvest and use as a template. We sought to develop a reliable experimental chimeric groin flap with free mobility and reliable bloods supply that can be twisted, relocated, and integrated easily with other materials.

MATERIALS AND METHODS

Ten male Wistar rats were included. The flap consists of a 2.5-cm skin paddle centered on the medial branch of the inferior epigastric artery and a 4.5/2-cm fat pad supplied by the lateral branch of the inferior epigastric artery. After being raised, flaps were resutured in their anatomical position. Flaps were followed up for 15 days. At the end of the study, the viability of flaps was analyzed by ultrahigh-frequency ultrasound, nontargeted contrast study, and histology assessment.

RESULTS

All flaps survived without significant complications. Nontargeted microbubbles spread evenly in both the superficial and deep flap. Ultrasound assessment at day 15 showed no significant areas of necrosis or edema. Histology examination of 3 random flaps confirmed vessel patency and flap viability.

CONCLUSION

We propose a simple, easy to harvest and reliable experimental flap which offers a main advantage of all-around mobility through its chimeric design. It is a suitable model for bioengineering studies as it can be used as a template for integration of tissue substitutes or stem cells, between its 2 components.

The Use of a Tetraminos Chimeric Free Flap in Lower Limb Trauma

Major trauma care has improved in the UK since the evolution and acceptance of specialist centers . A mission statement for major trauma care is “reduction in mortality and disability following trauma.” The care for extremity trauma has benefited from this specialization. Traumatic loss of skin integument in the extremities, especially over mobile joints, may lead to a compromised functional outcome. Modern reconstructive plastic surgery aims to provide flaps with minimal donor site morbidity.

In this case report, we present the use of two chimeric flaps undertaken sequentially (one acutely and the second delayed) around the knee joint to allow a greater range of motion and function after a severe traumatic event. In this clinical case, the original tissue defects had meant that a free flap was used to reconstruct an open fractured bone, and split skin grafting was undertaken on the anterior aspect of the knee. The latter was then replaced after some months of recovery.

Double free flaps in oral cavity and oropharynx reconstruction: Systematic review, indications and limits

The simultaneous use of two different free flaps, harvested from distinct donor sites, has demonstrated a reasonable degree of safety and success rates in head and neck composite defects reconstruction. Unfortunately, their relatively low frequent use, together with the lack of proper statistics on their management strategies, make their indications weak of robust conclusions to better define their role in common practice. The aim of the present study was to review the literature of the last 15 years regarding simultaneous free flap transposition, presenting advantages, disadvantages, and results of this technique, with the final purpose to propose an up-to-date panorama for the use of double free flap for complex head and neck defects reconstruction. Depending on which factors are present, surgeons may choose to select an approach that is theoretically safer, but yields less-than-ideal functional outcomes, such as local flap. Two free flaps may be necessary when the defect contains both a large, complex bony defect, large soft tissue needs, and proper surgical planning and meticulous monitoring continues to be the cornerstone of success.

Reconstruction of segmental mandibular defects: Current procedures and perspectives

Background

The reconstruction of segmental mandibular defects remains a challenge for the reconstructive surgeon, from both a functional and an esthetic point of view.

Methods

This clinical review examines the different techniques currently in use for mandibular reconstruction as related to a range of etiologies, including the different bone donor sites, the alternatives to free flaps (FFs), as well as the contribution of computer‐assisted surgery. Recent progress and the perspectives in bone tissue engineering (BTE) are also discussed.

Results

Osseous FF allows reliable and satisfying outcomes. However, locoregional flap, distraction osteogenesis, or even induced membrane techniques are other potential options in less favorable cases. Obtaining an engineered bone with satisfactory mechanical properties and sufficient vascular supply requires further investigations.

Conclusions

Osseous FF procedure remains the gold standard for segmental mandible reconstruction. BTE strategies offer promising alternatives.