Anatomical study on arteries of fasciae in the forearm fasciocutaneous flap

Tissue-engineered cellulose tubes for microvascular and lymphatic reconstruction: A translational and feasibility study

BACKGROUND

Lymphedema microsurgery is an emerging treatment modality, with dissimilar long-term outcomes. One of the main technical challenges in lymphatic microsurgery is the identification and availability of suitable donor vessels for anastomosis. Tissue engineering using biomaterials has demonstrated promise in addressing vessel quality issues in other fields, but its application in microsurgery is still limited.

METHODS

Decellularized cellulose tubes were developed and bioengineered by decellularizing stems of Taraxacum-Ruderalia. The microscopic structure, mechanical properties, and residual DNA content of the cellulose tubes were evaluated. Human and murine skin fibroblasts and dermal lymphatic endothelial cells were isolated and cultured for recellularization studies. Biocompatibility, proliferative capacity, and ex-vivo endothelialization of the cellulose tubes were assessed as potential interposition grafts. Finally, the engineered cellulose tubes were assessed as interposing xenografts for lymphovenous anastomoses (LVA) in an ex-vivo swine limb model.

RESULTS

The decellularized cellulose tubes exhibited a suitable microscopic structure, mechanical properties, and low residual DNA content. The tubes showed adequate biocompatibility, supported cell proliferation, and facilitated spontaneous ex-vivo endothelialization of lymphatic endothelial cells. In the swine limb model, LVA using the engineered cellulose tubes was successfully performed.

CONCLUSION

This translational study presents the use of decellularized cellulose tubes as an adjunct for micro and supermicrosurgical reconstruction. The developed tubes demonstrated favorable structural, mechanical, and biocompatible properties, making them a potential candidate for improving long-term outcomes in lymphedema surgical treatment. The next translational step would be trialing the obtained tubes in a microsurgical in-vivo model.

Soft-Tissue Coverage for Elbow Trauma

The elbow is particularly prone to trauma, and soft-tissue reconstruction can be challenging given the inherent motion, pressure, and lack of local tissue laxity. Small wounds and those without exposure of vital structures may be amenable to primary repair. Large wounds and those requiring more substantial structural or anatomic repair may require local, regional or free flap-based reconstruction. A comprehensive review of soft-tissue reconstruction of the elbow is provided to offer surgeons alternative options in complicated upper extremity wounds.

Dorsal forearm adipofascial turnover flap among the elderly

We have assessed the results of soft tissue cover on the back of the hand using an adipofascial turnover flap. From 2004 until 2007, 14 patients (mean age: 62 years) underwent reconstruction of extensive defects in the dorsum of the hand, using a forearm adipofascial turnover flap based on the perforators of the anterior interosseous artery covered with a split skin graft. The pivot point of the flap is typically 4-6 cm proximal to the level of the radial styloid process. In 93% of patients, the reconstruction healed without any problem. The adipofascial turnover flap is a useful and reliable method of reconstruction of the dorsum of the hand even in elderly patients.

The proximal radial artery perforator flap (PRAP-flap): an anatomical study for its use in elbow reconstruction

We investigated the anatomical vascular basis of the proximal radial artery perforator flap (PRAP-flap) and we report here the first clinical application in a case of reconstructive surgery as an alternative to traditional regional fasciocutaneous pedicled flaps or microsurgery solutions. In 16 unembalmed cadaveric forearms, the radial artery was slowly injected with acrylic resin through the brachial artery and the superficial flexor compartment was dissected. The flap was raised from the lateral and medial sides of the forearm toward the axis represented by the radial artery, and the characteristics (number, diameter, site and interval of origin, and course) of its collaterals were evaluated. In the proximal forearm, the vessels were less numerous (mean values 8.6 vs. 11.5, P < 0.05) but larger in diameter (mean values 0.7 vs. 0.4 mm, P < 0.05) than in the distal forearm. The first four proximal perforator arteries originated within a mean distance of 4.3 cm from the origin of the radial artery, with a 95% confidence interval of 3.8-4.8 cm. The perforator arteries followed the axis of the forearm and anastomosed in the fascial plane, forming longitudinal fan-shaped arterial chains, giving rise to an epifascial vascular network. This anatomical study allowed us to plan and perform a PRAP-flap in a 35-year-old woman who was suffering from comminuted fractures of the olecranon and distal epiphysis of the humerus and soft tissue loss from traumatic injury of the elbow. From the antebrachial surface, a proximally based radial forearm fasciocutaneous flap was raised, with a vascular pedicle of 16 x 5 cm, a cutaneous island of 4 x 5 cm, and a pivot point 5 cm from the interepicondylar line. The flap showed good immediate and long-term viability: it was completely incorporated with good pliability and the patient regained good functional quality of the elbow joint. The anatomical features and the demonstrative reconstructive result obtained in the here-reported surgical case support the clinical evidence that a reliable forearm skin paddle may be raised on a subcutaneous fascial axial pedicle supplied only by proximal perforators of the radial artery. The so-obtained PRAP-flap is useful for the coverage of elbow defects when other reconstructive options are no longer available.

Anatomical study of perforator arteries in the distally based radial forearm fasciosubcutaneous flap

We investigated the anatomical vascular basis of the forearm fasciosubcutaneous flap (FSC-F), fed by the distal perforator arteries of the fascia. This type of flap was proposed, in hand reconstructive surgery, to avoid the disadvantages caused by axial-pattern reverse radial forearm fasciocutaneous flap, based on ligation and rotation of the radial artery (RA). In eight fresh cadaveric forearms, the RA was injected slowly with acrylic resin and the superficial flexor compartment was dissected. Then the FSC-F was raised from the lateral margins of the sample to the median RA axis, and the collaterals of the RA (number, interval of origin, and caliber) were evaluated. The fascial branches of RA (mean number +/- SD: 20 +/- 3) originated mainly from the radial and ulnar sides of the RA. In the distal forearm the vessels were more numerous (mean value = 11.3 vs. 8.9; Student's t-test, P < 0.05) but smaller in diameter (mean value = 0.45 mm vs. 0.63 mm; Student's t-test, P < 0.05). The perforator arteries forked in a T-shape following the main axis of the forearm and anastomosed in the fascial plane, forming longitudinal fan-shaped arterial chains giving rise to the vascular epifascial network. Histological (hematoxylin-eosin, azan-Mallory, Weigert) and immunohistochemical (anti-von Willebrand factor) study of the FSC-F at different levels of sampling was also carried out. The epifascial branches of distal sections were smaller in diameter (78.3 +/- 35.5 microm) than those of intermediate (105.7 +/- 28.7 microm; Newman-Keuls test, P < 0.01) and proximal (116.8 +/- 31.2 microm; Newman-Keuls test, P < 0.001) sections. Our findings indicate that the perforator arteries and epifascial branches are smaller in the distal forearm, so that during surgical dissection, the safety distance from the radial styloid should take into account that also in the presence of a sufficient number of vessels in the distal forearm their caliber could be inadequate to the hemodynamic request of the flap. Thus, rather than on a theoretic distance from the radial styloid, the length of the flap should be based on an accurate evaluation of the individual vascularization of the forearm case by case.