Preliminary investigations on therapy thresholds for laser dosimetry, cryogen spray cooling duration, and treatment cycles for laser cartilage reshaping in the New Zealand white rabbit auricle

[Preliminary study on microdissection needle-assisted ear cartilage reshaping in vivo rabbit models]

Objective

To preliminarily investigate morghological changes of rabbits reshaping ear cartilage assisted by microdissection needle and explore feasibility of new therapy for ear deformity.

Methods

The bilateral ears of 5 male New Zealand rabbits (aged, 5-6 months) were fixed maintaining the curvature and randomly divided into 2 groups (5 ears in each group). The ears were stimulated by microdissection needle in experimental group and were not treated with stimulation in control group. The skin reaction in the experimental group was observed immediately and at 4 weeks after stimulation. Then, the fixtures were removed at 4 weeks, and the shapes of the ears were observed. The cartilages were harvested from the ears to examined morphological changes after HE staining, and measured the chondrocyte layer thickness.

Results

All rabbits survived until the end of the experiment. The skin has healed completely after 4 weeks in experimental group. After removing fixtures, the ears in the two groups all maintained certain forms momentarily; while 24 hours later, the ears in the control group mostly recovered original form, and the ears in the experimental group still maintained certain molding form until 8 weeks. HE staining showed there were smooth cartilage and uniform distribution of cells in the control group; the matrix staining was basically consistent; and the skin was normal appearance with epidermis, dermis, and cartilage of normal aspect. But the proliferation of chondrocyte with more layers of cells were observed in the experimental group. In addition, there were degeneration and injury of cartilage cells and connective tissue with necrotic cells and inflammatory cells at needle insertion sites. The chondrocyte layer thickness was (385.714±2.027) μm in the control group and (1 594.732±1.872) μm in the experimental group, there was significant difference between the two groups ( t=-759.059, P=0.000).

Conclusion

Rabbit ear cartilage can be effectively reshaped by microdissection needle. Proliferation of chondrocyte and changes in matrix can be found during the reshaping process.

Laser-assisted cartilage reshaping for protruding ears: A review of the clinical applications

OBJECTIVES/HYPOTHESIS

In 2006, our institute reported the first clinical use of laser-assisted cartilage reshaping (LACR) for protruding ears. Since then, the technique has been developed and refined. This article reviews the literature on the clinical application of LACR.

STUDY DESIGN

Literature review.

METHODS

A MEDLINE literature search was performed on LACR combined with cross-referencing. The period of search was 1993 to 2014. Search terms used were: laser, cartilage reshaping, protruding ears, LACR.

RESULTS

Only seven clinical studies using three different wavelengths were found in the literature: 1,064 nm (Nd:YAG), 10,600 nm (CO2), and 1540 nm (Er:Glass). Clinical outcomes, laser wavelength and parameters, and patient satisfaction are discussed in each case.

CONCLUSIONS

The success rate for ear reshaping achieved with LACR appears promising. The use of this noninvasive technique will increase in the near future.