Reinnervation of segmented latissimus dorsi muscle with the distal stump of the thoracodorsal nerve: A preliminary experimental study in rats

Latissimus Dorsi Myocutaneous Flap Procedure in a Swine Model

BACKGROUND

As surgical research expands in both breadth and scope, translational models become increasingly important. The accessibility, reproducibility, and clinical applicability of translational models is of vital importance to ensure adequate and accurate research. Though different flap models have been described, the literature lacks an in-depth, technical description of an easy large-animal preclinical model. We here describe the procedure for elevation of a latissimus dorsi flap in a swine. This flap contains muscle and skin that can be isolated on a vascular pedicle, transferred as a free flap, perfused, or innervated/denervated as dictated by the needs of the experiment.

METHODS

Five different latissimus dorsi flaps were elevated in miniature swine. Careful attention was paid to anatomical landmarks and optimal placement of incision, dissection, and retraction. Temporary ischemia with vascular clamping was performed along with serial digital and infrared imaging both intra- and postoperatively. In three of the flaps with induced ischemia, the animal was observed for a 30-day follow up with daily photodocumentation and intermittent biopsy.

RESULTS

A reproducible latissimus flap model was designed with optimized conditions. In the animals in which flaps were followed postoperatively, complete healing was seen within 30 days without evidence of procedure-related ischemia or loss of motor function.

CONCLUSION

We have identified and described a pre-clinical large animal flap model that can be easily reproduced for translational studies of multiple scientific areas including flap-based repair, ischemia, ischemia reperfusion, and operative technique. This provides an important model for ready replication in preclinical studies of many varieties.

Evaluation of Donor Morbidity following Single-Stage Latissimus Dorsi Neuromuscular Transfer for Facial Reanimation

BACKGROUND

Single-stage latissimus dorsi neuromuscular transfer has been a valuable option for dynamic smile reanimation. However, there is a paucity of studies evaluating the potential donor morbidity in such cases. The present study aimed to comprehensively analyze the donor morbidity following functional latissimus dorsi muscle transfer.

METHODS

Patients who underwent single-stage functional latissimus dorsi muscle transfer for smile reanimation between 2002 and 2016 were reviewed. Postoperative complications and functional impairments at the donor sites were evaluated. The Quick-Disabilities of the Arm, Shoulder and Hand questionnaire was used for assessing postoperative donor-site function.

RESULTS

Sixty patients, including 12 pediatric (18 years or younger) patients, were analyzed. Mean length of a harvested thoracodorsal nerve was 14.9 cm. Fourteen patients were treated with a dual innervation technique, in which both a descending and a transverse branch of the thoracodorsal nerve were harvested. Donor complications were observed in seven cases; all of them were seromas and resolved by simple aspiration. No other complications including scoliosis and sensory and/or motor disturbances in the upper extremities were encountered. Fifty patients responded to the Quick-Disabilities of the Arm, Shoulder and Hand questionnaire at a median follow-up of 51 months. The average score was 2.64, and all but three patients scored less than 10. No variables, including patient age (pediatric versus adult) and the use of a dual-innervation technique, affected the donor morbidities, including the functional deficits.

CONCLUSION

Single-stage latissimus dorsi neuromuscular transfer for facial reanimation might be associated with a low rate of complications and minimal functional morbidity at the donor site.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Drug-Induced Atrial Fibrillation Complicates the Results of Flap Surgery in a Rat Model

The relationship between atrial fibrillation (AF) and flap survival has not been fully characterized. Therefore, the goal of this study was to investigate the effect of AF on survival areas of pedicled flap and survival rates of free flap in an experimental rat AF model. An aconitine-induced rat AF model was established without intubation anesthesia. Survival areas of the pedicled rectangular epigastric flap were compared between AF rats (n = 7) and control rats (n = 7), and survival rates of the free epigastric flap were compared between AF rats (n = 10) and control rats (n = 10). Animals that died during the study or in which AF was not induced were excluded from study. A total of 64 rats were assessed in this study. Atrial fibrillation was induced with a success rate of 77.8% (21/27) throughout the study. Pedicled flap survival area was significantly higher in controls (75.1 ± 9.0%; n = 7) than that in AF animals (55.7 ± 13.0%; n = 7) (P < 0.01, nonpaired Student t test). Free flap survival rates were 80% in controls and 40% in AF animals (P = 0.07, χ² test). This is the first study to develop an aconitine-induced model of AF in rats. Atrial fibrillation has a detrimental effect on survival areas of the pedicled flap and survival rates of the free flap.