Although the traditional material for myringoplasty is temporal fascia, the rigidity of a cartilage graft has obvious benefits in reducing retraction of the tympanic membrane (TM).1, 2 A study using a Doppler interferometer suggested that an acoustical benefit could be obtained by thinning the cartilage slice to 0.5 mm.3 However, this advantage is offset by unacceptable curling of the graft that occurs when the cartilage is thinned and the perichondrium is left attached to one side.4
We believed that a reduction in the curling would allow the sliced cartilage to adapt more easily to TM reconstruction. We herein report a microslicing technique for auricular cartilage using a commercially available cutting device (KURZ Precise Cartilage Knife Set, cat. no. 8000 155; Heinz Kurz Medizintechnik, Dusslingen, Germany). This technique was modified after estimating the degree and direction of the curl of the sliced cartilage in hematoxylin-eosin–stained sections.
HEMATOXYLIN-EOSIN STAINED SECTIONS
Using hematoxylin-eosin–stained sections of full-thickness conchal cartilage, cartilage that was sliced in half and cartilage that was sliced on both sides were investigated. The cartilage that was sliced in half curled toward the perichondrium, whereas the cartilage sliced on both sides did not curl. Thus, when perichondrium is left on one side of the cartilage, the cartilage tends to curl toward it (Fig. 1). It follows that if one begins with a curved piece of cartilage, and then thins it so as to leave perichondrium only on the side that was originally convex, the remaining perichondrium will tend to flatten out the cartilage graft.
MODIFIED MICROSLICING TECHNIQUE
First, a curved, nonflat conchal cartilage is harvested, and the degree of further curling is predicted (Fig. 2A). Distant plates of 0.2- to 0.3-mm thickness are used. The cartilage is placed on the cutting device with its convex side downward and the plane touching the bottommost part of the convex side parallel to the blade edge (Fig. 2B–D). The cartilage is covered with the other piece of the cutting device, and the screw is tightened. Then, the edges of the cartilage and the cutting device are matched (Fig. 2E). The blade is carefully placed into the cartilage under a surgical microscope, and 0.4- to 0.5-mm thick cartilage is identified. Then the cut is made. When the cutting device is opened, a markedly curling slice of cartilage is obtained on the blade (Fig. 2F), and a flat 0.4- to 0.5-mm-thick slice of cartilage is obtained on the distant plate (Fig. 2G). In this way, two types of cartilage plates with perichondrium are prepared (Fig. 2H).
The first cartilage myringoplasty using septum cartilage was performed by Salen5 and Jansen6 in 1963. In the 1960s, Heermann7 developed the cartilage palisade method, and Goodhill8 introduced the first composite cartilage-perichondrium graft in 1967. Since then, various methods have been reported.1, 2 A review of the literature revealed that cartilage-perichondrium composite autografts tend to survive and maintain their form, and it is advisable to preserve the perichondrium on at least one side. Cartilage and composite grafts have recently gained increasing acceptance in cases at high risk for failure, such as recurrent or total perforations, severely atelectatic ears, or cholesteatoma.
Overbosch9 was the first to describe a microslicing technique to improve the acoustic properties of the reconstructed TM. Zahnert et al.3 demonstrated that acoustical benefit could be obtained by thinning the cartilage to 0.5 mm. Using the cutting device, the transplants were thinned to slices of the specified thickness.10 TM reconstruction using large, trimmed, curved cartilage plates reportedly maintained sufficient long-term mechanical stability and provided acceptable acoustic transfer characteristics.10, 11
Auricular cartilage is more convenient than septum because the auricle can be harvested in the same operative field and simply attached to the perichondrium. However, because the auricular cartilage is elastic, it curls after slicing. Before this study, because we obtained two curling cartilage plates when we harvested a large piece of flat auricular cartilage and sliced it with the cutting device, we occasionally tried to improve the plate design and manipulation. Currently, before harvesting the cartilage, we design the cartilage plate with the desired thickness, curve, and size, and select flat or curved full-thickness cartilage. We believe that this technique facilitates the design of the sliced cartilage.