Neurovascular anatomy of pronator quadratus for reanimation of blepharoptosis

Neurovascular anatomy of the platysma muscle for blepharoptosis repair: a cadaveric study

PURPOSE

This study aimed to define a new surgical method using a neurotized platysma free flap to provide dynamic reanimation, enhanced functional recovery, and low morbidity for blepharoptosis repair.

METHODS

Ten hemifaces and neck halves of five formalin-fixed cadavers were included in the study. The origin of the neurovascular structures of the pedicle was identified at the submandibular triangle. A 5 × 3 cm platysma flap was dissected. For the recipient side, the main donor vascular structures were observed at the frontal part of the temporal region. The diameters of the donor structures were measured with a digital Vernier caliper. The statistical analysis of the study was performed with Jamovi statistical software version 2.3.36. P < 0.05 was accepted as a statistically significant value.

RESULTS

At the donor region, the pedicle included branches of the cervical branch of the facial nerve and the facial artery in all specimens. However, the venous graft pedicle origin could be either the facial vein or the lingual vein. At the recipient region, the mean diameters of the most anterior nerves, arteries, and veins were 1, 2.03, and 2.37 mm respectively. In a side comparison of pedicle variables, only pedicle artery diameter and lateral palpebral commissure-anterior superior point of auricula distance had statistically significant differences between hemifaces.

CONCLUSION

A 5 × 3 cm size platysma flap located in the submandibular trigone would be a good choice for functional blepharoptosis surgery. The thin structure and the appropriate neurovascular pedicle structure should enable performing a successful flap transfer.

Pronator Quadratus Musculo-osseous Free Flap for Wide Hard Palatal Defect Reconstruction: An Anatomical Study

Wide hard palate defects include congenital and acquired defects that are six square centimeters or larger in size. Obturator prostheses and autologous soft tissue transfers have been used to reconstruct palatal defects. This study aims to repair wide, hard palatal defects by using a pronator quadratus musculo-osseous free flap to achieve subtotal reconstruction. Seventeen formalin-fixed cadavers were dissected. Free musculo-osseous pronator quadratus flaps were prepared after a 12 cm curvilinear volar skin incision. Standard 30 × 23 mm (690 ± 52.12 mm²) hard palate defects were made by chisels and saws. A subcutaneous tunnel was created between the mandibular edge cross point of the facial vessels and the retromolar trigone through the subcutaneous to the superficial musculoaponeurotic system by dissection. Area measurements of the pedicle and palate defects were performed by the ImageJ program (National Institutes of Health, Bethesda, MD, USA) on drawings over an acetate layer of materials. Mandibular distances of gonion-facial vessel cross point (a), gonion-gnathion (m), and facial vessels' cross point-retromolar entrance point (h) were measured. Ratios of h/m and a/m were calculated. The mean pronator quadratus area was 2349.39 ± 444.05 mm², and the arterial pedicle pronator quadratus diameter was 2.32 ± 0.34 mm. The mean pedicle length of the pronator quadratus was 117.13 ± 8.10 mm. Study results showed that musculo-osseous pronator quadratus flaps' bone and muscle parts perfectly fit on the defects in all cadavers. Pronator quadratus musculo-osseous flap is a feasible surgical option for wide, hard palatal defect reconstruction strategies.

Use of free radial forearm and pronator quadratus muscle flap: Anatomical study and clinical application

The authors present an anatomical study and clinical experience with radial forearm flap (RFF) and pronator quadratus muscle (PQM) application in the reconstruction of various body areas. The aim was to describe the anatomical placement and proportions of the PQM, the anatomical location of the major arterial branch of the radial artery supplying the PQM, and the application of this knowledge in clinical practice. The anatomical study was based upon an analysis of 13 fresh adult cadaver upper extremities, of which nine were female and four male; both arms from the same donors were used in four cases. The study of the PQM was performed using a dye-containing intraarterial injection, standard macro- and micro-preparation techniques, and chemical digestion. The data on the PQM size in males and females, thickness of the radial artery branch (the principal artery nourishing the muscle), and its position were analysed. The radial artery branch nourishing the PQM was identified in all cadaveric specimens of the anatomical study. In addition, 12 patients underwent reconstructions of soft and bony tissue defects using a RFF + PQM (pedicled or free flap). The radial artery branch perfusing the PQM was identified in all cases. The flap was used for the management of defects of the head (seven cases), arm (three cases) and lower leg (two cases). The harvest site healed well in all cases and, with the exception of one case in which a partial necrosis of the flap was observed, all flaps remained viable, which demonstrated the safety of the method.