14Harvesting Cartilage, Fascia, and Bone Grafts

FWhy autografts, and where they come from

Most ossiculoplasties are built, at least in part, from the patient’s own tissue. The reconstruction needs three different things at different moments: a supple membrane to close and rebuild the drum, a stiff sheet to shield a prosthesis head or resist retraction, and sometimes a rigid strutto bridge an ossicular gap. Three autograft families supply them — temporalis fascia (and perichondrium) for the membrane, tragal or conchal cartilage for the stiff sheet, and mastoid cortical bonefor the strut. All are autologous, so they are not rejected and carry no risk of disease transmission, and all heal with very low extrusion rates — the enduring appeal that kept biological grafts central to tympanoplasty from Wullstein’s founding descriptions onward [1956].

Their second great advantage is logistic: every donor site lies within the operative field. Fascia is reached by extending the same postauricular or endaural incision a little higher; auricular cartilage is taken through a small hidden incision on the ear; and cortical bone is simply collected from the mastoid the surgeon is already drilling. No separate distant incision, no tissue bank, no second consent for a remote donor site. The explorer below maps the five sites and the chief consideration at each before we take them one at a time.

FHarvesting temporalis fascia

Temporalis fasciais the loose areolar fascia overlying the temporalis muscle, just above the root of the zygoma. Through the postauricular or endaural incision the dissection is carried superiorly, the fascia is incised, and a sheet is peeled free from the muscle, which is left undisturbed. Surgeons take a piece a little larger than the perforation — roughly 20 × 20 mmis ample — and then clean it of fat and stray muscle fibres. Some prefer the more superficial “loose areolar” layer for its pliability and transparency, reserving the deeper true fascia for revision work; either heals well.

A freshly harvested sheet is thin and floppy, so most surgeons press or air-dry it flat on a metal block until it is rigid enough to handle and slide accurately into position, after which it rehydrates and softens again in the middle ear. Whether the graft goes in dry (pressed and stiff) or wet(fresh and soft) has been argued for decades, but a meta-analysis of eight randomised trials and nearly a thousand patients found no significant differencein graft take, hearing, or healing time between the two — so drying is a handling convenience, not a determinant of success[2023]. The donor site needs only haemostasis and closure; the scar disappears into the hairline and the muscle bulk is preserved.

THarvesting tragal and conchal cartilage

Where the reconstruction must resist retraction or carry a load— a shield over a prosthesis head, a palisade for a subtotal perforation, a graft for an atelectatic or revision ear — cartilage is the autograft of choice. Dornhoffer’s large series established cartilage-perichondrium as a durable, low-extrusion material that closes the difficult drum reliably, with a 96% closure rateacross a thousand ears [2003]. Three auricular sub-sites are used, each with its own character:

• Tragus— a flat plate of cartilage taken through a small incision on the medial tragus, cosmetically hidden. Its flatness suits shields and island grafts; it is the everyday workhorse.
• Scapha and cymba— curved cartilage reached through the postauricular approach, useful when more length or a natural curve is wanted, and with the lowest donor-site sensory morbidity of the three.
• Concha— the largest single piece of auricular cartilage, naturally curved and ideal for large or total reconstructions, but the site with the highest long-term donor sensory change and the greatest risk of a contour deformity if over-harvested.

Whichever site is chosen, the principles are the same: lift the perichondrium (leaving it attached on one face when an island graft is wanted), take only as much cartilage as the reconstruction needs, preserve the antihelical rim and the tragal tip so the ear keeps its shape, and thin the graft toward roughly 0.5 mm before shaping it into a shield, island or palisade. The step-through below contrasts the harvest sequence for fascia, cartilage and bone.

THarvesting cortical bone

When an ossicular gap needs a rigid columella and the native ossicles are diseased or absent, the mastoid being drilled is a ready source of dense cortical bone. Shavings or a small block are collected during the mastoidectomy and sculpted into a strut that bridges the stapes head to the drum or the malleus handle to the stapes. There is no separate donor site at all, and the bone is the patient’s own, so it integrates without rejection. Long-term series report durable hearing — mean air-bone gaps falling from the low-30s to around 20 dB and holding stable over several years, with no extrusion or necrosis in well-selected ears [2014]. (Cortical shavings collected as bone pâtéalso serve to obliterate a cavity or rebuild a canal wall, though that is a mastoid-cavity rather than an ossicular use.)

The crucial caveat is that a cortical strut is not inert. Histology of columellas removed years after implantation shows most are a mixture of living and dead bone: the graft is slowly revascularised and remodelled by creeping substitution, much like an orthopaedic cortical graft[1987]. In a healthy, well-aerated ear this incorporation is benign, but in a poorly aerated, inflamed or draining ear the balance can tip toward net resorption and delayed conductive loss. That biology dictates technique: keep the strut light and correctly sized (an over-long, heavy column destabilises and erodes the drum), protect the drum interface with an interposed cartilage shield, and seat the graft in a cavity with healthy mucosa and good aeration.

CDonor-site morbidity

For all three families, donor-site morbidity is low — but it is not zero, and the differences matter when counselling a worried patient. Fascia harvest leaves only a hidden hairline scar and preserves the muscle, with negligible functional consequence. Cortical bone has no separate donor site at all, since it comes from the mastoid already being opened. The most discussed morbidity is that of auricular cartilage, and here the discriminating issue is not cosmesis but sensory change in the donor skin. In a careful follow-up of ear-cartilage harvest, early problems were dominated by haematoma and a little sensory impairment, while at long-term review sensory impairment was the commonest finding and was confined to the conchal donor site; anthropometric change in ear dimensions averaged only a couple of millimetres [2008]. The chart places those figures side by side.

The choice of which auricular site therefore has a measurable effect. A direct comparison of the scapha and the tragus found that, although neither caused cosmetic dissatisfaction or measurable change in ear shape, clinical donor-site sensory changes were significantly less common with the scapha than with the tragus, particularly after a retroauricular approach [2020]. Ranked by sensory morbidity, the auricular sites run roughly scapha (least) → tragus → concha (most). None of these is a reason to avoid cartilage when the ear needs it, but they are good reasons to choose the site thoughtfully and to harvest conservatively.

CChoosing and sparing the donor site

Harvest decisions follow from what the reconstruction must do and from the patient in front of you. The practical logic is simple. If the job is to close a perforation or rebuild a vibrating drum in a favourable ear, take fascia or bare perichondrium— the thinnest, most acoustically transparent option, with the least donor morbidity. If the drum must instead shield a prosthesis, resist retraction or carry a load, take cartilage, and pick the sub-site by need and by the patient’s concerns: the tragus for a flat shield, the scapha or cymba when donor numbness must be minimised, and the concha only when a large, curved piece is genuinely required. If an ossicular gap needs a rigid strut and the ossicles are unusable, sculpt cortical bone from the mastoidectomy already in progress.

Three habits keep donor-site morbidity to a minimum whatever the tissue. Take only what you need: an over-harvested concha flattens the antihelix, an over-long bone strut destabilises and erodes the drum, and a needlessly large fascia sheet wastes nothing but time. Preserve contour and structure: leave the antihelical rim, the tragal tip and the temporalis muscle intact, and keep cartilage thinned but not fractured. And match the tissue to the demandrather than to habit — the same operation may draw on two or three of these donor sites at once, fascia to seal and cartilage to shield over a bone or prosthetic columella. Chosen and harvested this way, the patient’s own tissue does almost everything the reconstruction asks of it, at a donor-site cost that is, in experienced hands, very small indeed.