High-volume hydrodissection for abdominally based free flaps: Preliminary results

Hydrodissection to create conjunctival flaps in dogs with corneal ulcers

Background and Aim

Hydrodissection is a liquid injection technique that is rarely used in animal ophthalmic procedures. The use of this technique in the creation of conjunctival flaps for the treatment of corneal ulcers in dogs can improve the outcome, task, and comfort for patients. This study aimed to evaluate the use of hydrodissection in the creation of conjunctival flaps in dogs with corneal ulcers.

Materials and Methods

This study focused on a surgical procedure for creating conjunctival flaps in the eyes of 17 dogs with deep corneal ulcers. We divided the patients into two groups: Hydrodissection was performed in the first group (G1) and conventional divulsion without hydrodissection in the second group (G2). In G1, the conjunctival flap was created by subconjunctival injection of 1 mL of 0.9% sodium chloride, followed by flap construction. The flap was constructed through conventional divulsion using iris scissors in the G2. The operative time, degree of bleeding, and ease of conjunctival divulsion were evaluated during the procedure. Blepharospasm, hyperemia, edema, and scarring of the conjunctiva were evaluated during the post-operative period. Post-operative complications, notably suture dehiscence, were recorded in each group.

Results

Hydrodissection is an easy-to-perform maneuver that optimizes the construction of conjunctival flaps. There were no statistical differences in the parameters used to evaluate the trans- and post-operative period between the groups. The volume of sodium chloride administered in the conjunctiva ranged from 0.5 mL to 1 mL in G1. Dehiscence of the flap sutures was observed in four patients (two in G1 and two in G2), with no significant difference between the groups.

Conclusion

Hydrodissection facilitates the construction of conjunctival flaps in dogs with corneal ulcers, affording greater comfort to patients and proving to be an excellent option for ophthalmologists.

Intramuscular Deep Inferior Epigastric Vessels Are Insulated by Perimysial Fibroadipose Tissue Network

Background The difficulty of elevating a deep inferior epigastric perforator (DIEP) flap largely depends on the intramuscular course of the vessel and the perforator. Previous studies, however, have lacked histologic descriptions of the vessels and surrounding structures. The present study analyzed the histologic aspects of the deep inferior epigastric vessels and perforators, focusing on their perivascular relationships with muscle fibers.

Methods The abdomen of a cadaver was histologically evaluated to identify intramuscular deep inferior epigastric vessels. Tissue samples were stained with hematoxylin and eosin and with Masson trichrome stain to visualize fibrous components. Twenty-one DIEPs from 12 patients were also evaluated to determine the histologic aspects of the perivascular structure. In the cross-section of each perforator and adjacent tissue, the perforator-to-muscle distance and trichrome-stained area were measured, and the correlation of the perforator size with the perforator-to-muscle distance and the percent collagenous portion of the distance were determined.

Results Histologic analysis showed that the deep inferior epigastric vessels and perforators were encased by perimysial connective tissue and were not in direct contact with the muscle fibers. The smaller perimysia branched out from the larger perimysia, forming an interconnecting network structure. Correlation analysis showed that larger vessels had more collagenous portions in the perimysial structures (Spearman's ρ = 0.537, p = 0.012).

Conclusion The deep inferior epigastric vessels and perforators reside in a perimysial fibroadipose tissue network. This may provide surgeons with a microscopic perspective during DIEP dissections.

Clinical Relevance Statement Having an idea of the perforator anatomy in microscopic level can help us to perform safer perforator dissections.