Cartilage Tympanoplasty - technical
Tympanoplasty is the reconstruction of the tympanic membrane (TM) in such a manner that specific middle ear pathology, such as cholesteatoma, chronic otitis media, or an ossicular chain defect, is also addressed. Cartilage tympanoplasty refers to the use of autogenous cartilage as graft material to reconstruct or reinforce portions of the TM.
Techniques utilizing cartilage are typically reserved for persistent perforations, severe retractions, cholesteatoma, and revision surgery; however, cartilage is also employed by many for primary tympanoplasty. For more information on tympanoplasty and middle ear surgery please refer to: Tympanoplasty, and Ossiculoplasty.
Cartilage has long been used as a graft material in middle ear surgery. Utech was the first to begin using it in the 1950s. Others, such as Salen and Goodhill, began using cartilage for repairing portions of the TM; however, Heermann was the first to establish the use of cartilage and the palisade technique for chronic middle ear disease (Tos 2009). Recently it has also been employed to reconstruct large portions of the TM. The use of cartilage to reconstruct the pars tensa in cases of perforation, atelectasis, and cholesteatoma has expanded the indications and utilization of cartilage in tympanoplasty. While cartilage has classically been implemented for ossiculoplasty, this entry specifically addresses the use of cartilage in type I tympanoplasty.
Cartilage differs from traditional graft material, such as fascia and perichondrium, primarily due to its increased thickness. This might suggest an increased rigidity, with resulting conductive hearing loss; however, several studies have demonstrated that hearing results are no different than with fascia (Tos 2009; Milewski 1993; Amedee et al. 1989). Moreover, it is precisely this increased thickness and rigidity that makes cartilage an ideal graft material capable of resisting the resorptive and retracting forces of continuous ▶eustachian tube dysfunction.
Many variations exist regarding the shape and placement of cartilage grafts. Most of these fall under two distinct techniques: the cartilage/perichondrium island flap and the palisade technique. The choice of technique is generally dictated by the specific otologic pathology. For example, the cartilage island flap is preferred for the repair of high-risk perforations and the atelectatic ear while the palisade technique is preferred in cases of cholesteatoma when ossiculoplasty is needed around an intact malleus.
Fate of Graft Material
Cartilage grafts are largely nourished by diffusion. While degeneration of the chondrocytes occurs, the cartilage retains its framework of lacunae and, thus, its rigid quality. In both experimental and clinical studies, cartilage has been shown to be well tolerated by the middle ear, and long-term survival should be expected (Kerr et al. 1973; Don and Linthicum 1975).
The surgical approaches for cartilage tympanoplasty are no different than those for traditional tympanoplasty and middle ear surgery. In general, a postauricular approach provides good visualization and access. This is the most commonly used approach due to the tendency of surgical candidates to have more extensive middle ear disease. However, for small postauricular perforations or retraction pockets, a transcanal or endaural approach may be utilized. The specifics of these approaches with regard to the TM and middle ear are detailed elsewhere in this text, see Tympanoplasty for more information. While many surgeons may place their graft material on the lateral surface of the TM in an onlay technique, the underlay technique of placing the graft on the medial surface of the TM is preferable and will be described herein.
Harvesting of Cartilage
Cartilage may be obtained from the tragus (most commonly) or the conchae (cymba or cavum). Tragal cartilage is ideal because it is thinner and flatter than conchal cartilage. In order to harvest tragal cartilage, the initial incision is made on the medial surface of the cartilage and extending through the medial skin, medial perichondrium, cartilage, and lateral perichondrium. A 2-mm strip of cartilage at the dome is preserved for cosmesis. Scissors are then used to dissect in the plane between the skin and the perichondrium. Dissection is extended as far as possible in each direction in order to deliver the largest piece of cartilage possible (typically 15 mm 10 mm in children and slightly larger in adults).
Cymba cartilage is slightly curved and is more suitable for use in the palisade technique. If a postauricular approach is utilized, cymba cartilage can be readily obtained by extending dissection anteriorly in the plane along the perichondrium of the posterior auricle.
Cartilage thickness does not appear to differ between children and adults. However, there is a tendency for the perichondrium to be more adherent in children. In patients over 65 years, the cartilage may be slightly brittle and gentle handling of the graft is advised.
The Cartilage/perichondrium Island Flap
Creation of a cartilage/perichondrium island flap begins with the harvesting of tragal cartilage. The perichondrium on one side of the graft is preserved. A round knife is then used to create a disk that measures 7–9 mm in diameter, which can be used for total TM reconstruction. A 2-mm strip of cartilage is then removed centrally (while preserving the perichondrium) to accommodate the malleus handle. A triangle of cartilage may also be removed from the posterior-superior portion of the graft in cases where the incus is still present. The graft is now composed of two cartilage islands that can flex at the malleus to conform to the normal, conical shape of the native TM.
An underlay technique is used to place the graft, with a tail of perichondrium extending along the posterior canal wall. The malleus fits into the carved central groove of the cartilage islands. Some surgeons have reported additional scarring and fixation if the perichondrium is placed on the side facing the middle ear; therefore, it is recommended that the graft is placed in such a fashion that the perichondrium is facing the ear canal (Tos 2009). Gelfoam (Upjohn Laboratories, Kalamazoo, MI) is packed into the middle ear anteriorly and posteriorly to support the graft. A single pieced of Gelfoam is placed lateral to the graft, and the ear canal is filled with watersoluble antibiotic ointment.
The Palisade Technique
Instead of using a single piece of cartilage, as with the cartilage/perichondrium island flap, the palisade technique generally refers to using individual pieces of cartilage to reconstruct the TM. This technique has been preferred in cases of chronic eustachian tube dysfunction and cholesteatoma and when precise cartilage placement is needed around an intact malleus. It has also been suggested that palisade reconstruction allows for better detection of residual cholesteatoma growth postoperatively because the palisades enable the reconstruction to bulge outward when cholesteatoma recurs (Uzun et al. 2005).
Heermann’s palisade technique entailed the use of several narrow strips of cartilage that were carefully inset and layered across the defect (Tos 2009). This technique has subsequently been modified in multiple ways, including the use of a variety of cartilage shapes and thicknesses as well as changes to the inset and placement with utilization of modern ossicular prostheses. The use of several semicircular shapes of cartilage to reconstruct the TM, often referred to as the “mosaic” technique, is preferred as this method allows for more exact graft coverage and placement. The graft can bemodified in a “cut as you go” fashion for a precise fit between the reconstructed TM, the remaining malleus or ossicular prosthesis, and the canal wall.
Cartilage can be harvested from either the cymba or the tragus. The perichondrium is removed from one side of the cartilage and is used to reinforce the reconstruction after graft placement. In the traditional palisade technique, the cartilage is sliced into several rectangular strips measuring approximately 1–2 mm. These strips are then placed side by side to create the new TM. This technique has been criticized due to the space left between the strips of cartilage. Therefore, many surgeons prefer to layer the palisades similar to the tiles on a roof. Perichondrium is then placed over the grafts to encourage epithelialization.
With the mosaic technique, a single semilunarshaped piece is placed against the malleus and on top of the prosthesis in order to reconstruct a major portion of the posterior TM initially. Once this piece has been positioned, a second semilunar piece is placed between the first piece and the canal wall to reconstruct the scutum precisely. The remaining spaces are then carefully filled with small slivers of cartilage in a jigsaw-puzzle fashion. The entire reconstruction is then covered with a large piece of perichondrium that further drapes over the posterior wall.
The patient is typically seen in the clinic 1–2 weeks postoperatively. Ear wicks or other packing materials are removed at this time, and residual ointment is suctioned from the ear canal. Antibiotic ear drops are prescribed if any additional residue remains. At 2–3 weeks from the day of surgery, the patient is instructed to begin Valsalva maneuvers to inflate the middle ear. A postoperative audiogram is usually obtained at 6–8 weeks post-surgery. The development of a conductive hearing loss should prompt the examination for middle ear effusion or residual cholesteatoma.
Proper graft sizing and placement intraoperatively are key to preventing postoperative complications. Island grafts that are too small can be rectified by using cartilage slivers, as in the palisade technique, to ensure complete coverage. Grafts that are too large should be trimmed to fit precisely at the bony annulus. An intact chain with a medially rotated malleus may alter the position of the graft. This can be remedied by either modifying the manubrium for a better fit or by removing a larger strip of cartilage from the island graft. Further manipulation or displacement of the chain is discouraged due to the risk of acoustic trauma.
The most commonly encountered postoperative complications of cartilage tympanoplasty generally stem from the inability to examine the status of the middle ear through the opaque cartilage graft. Persistent middle ear effusion with resultant conductive hearing loss is seen in about 7–10% of cases (Brackmann et al. 2010), and tympanograms are unreliable as they will frequently exhibit a lowvolume type B tympanogram. Therefore, if a conductive hearing loss is found, a CT scan may be needed to assess the middle ear.
Placement of a ▶tympanostomy tube is often difficult following cartilage tympanoplasty and typically necessitates taking the patient to the operating room. Silastic t-tubes or titanium tubes specifically designed for cartilage tympanoplasty (Razrbac Tube, Grace Medical Inc., Memphis, TN) are used in lieu of grommet tubes as these will not fit properly due to the thickness of the cartilage graft. It is also often necessary to remove an ellipse of cartilage to accommodate the tube. In patients with severe and pervasive eustachian tube dysfunction (such as in those with craniofacial abnormalities or a history of radiation therapy or multiple otologic surgeries), it is advisable to consider tube placement at the time of the initial tympanoplasty.
Surveillance of the middle ear following cholesteatoma is also made difficult by the opaque cartilage graft. Therefore, if major spillage of the cholesteatoma sac occurs during the initial removal, a second-look surgery should be considered. However, because residual cholesteatoma in the epitympanum is often hidden from view in traditional tympanoplasty reconstructions, many surgeons utilize surveillance CT scans to detect recidivistic disease after either traditional or cartilage reconstruction. Ultimately, residual cholesteatoma typically manifests as a ▶conductive hearing loss, which may prompt CT imaging.
The use of cartilage as a graft material for tympanoplasty should generally be considered in any ear thought to be at a high risk for failure using traditional graft materials, such as fascia or perichondrium. These high-risk situations are commonly encountered with the atelectatic ear, cholesteatoma, revision surgery, perforations anterior to the annulus, draining perforations at the time of surgery, perforations larger than 50% of the TM, and bilateral perforations. Cartilage has been particularly useful in the case of the atelectatic ear as the increased rigidity of the cartilage helps to resist the negative pressure forces of ▶eustachian tube dysfunction, and its efficacy over fascia has been extensively reported (Sheehy 1985; Glasscock and Hart 1992; Levinson 1987). Furthermore, cartilage has also proven useful in reinforcing the scutum and preventing recurrent retraction pockets in cholesteatoma surgery.
Cartilage tympanoplasty is applicable in both adult and pediatric patients; however, success in pediatric patients requires careful patient selection. In general, tympanoplasty is avoided during the otitis-prone years (<3 years) and in cases where contralateral ear disease is present. With a normal contralateral ear, cartilage tympanoplasty is typically performed around age 4. When contralateral ear disease is present, ▶adenoidectomy is considered, and the tympanoplasty is performed around age 7 (Brackmann et al. 2010).
In both adult and pediatric patients, an effort is made preoperatively to optimize middle ear aeration and resolve otorrhea. Thus, performing the Valsalva maneuver is encouraged (or use of the Otovent in young children). Those unable to insufflate the middle ear space or those with concomitant sinonasal disease are treated with nasal steroid sprays. Otorrhea is treated with antibiotic- and steroid-containing topical solutions and aural cleaning for 6–8 weeks preoperatively. Smoking cessation is also strongly encouraged.
While the indications for cartilage tympanoplasty have broadened, the contraindications have been narrowed. Efforts to optimize the middle ear environment are advised in all patients, and, therefore, eustachian tube dysfunction and otorrhea should be maximally treated prior to surgery. While a draining ear at the time of surgery has classically been associated with graft failure, it should not necessarily be considered a contraindication to cartilage tympanoplasty. However, due to the opaque nature of the reconstructed TM postoperatively, if surveillance via audiometry or CT is not available, traditional fascia tympanoplasty should be considered.
Cartilage tympanoplasty has the primary advantage of a more rigid reconstruction that can resist the resorption and retraction associated with chronic middle ear dysfunction. Cartilage is well tolerated in the middle ear environment and exhibits long-term survival, and successful graft take can be expected in over 95% of patients (Brackmann et al. 2010; Dornhoffer 1997, 1999, 2003). Therefore, in patients with chronic middle ear disease or cholesteatoma, cartilage techniques can provide a more stable, longlasting repair.
Given the increased thickness of cartilage grafts compared to the native TM, it would be expected that the acoustic properties and postoperative hearing results would differ from traditional fascia tympanoplasty. However, multiple studies have demonstrated good closure of the air-bone gap with cartilage tympanoplasty (Brackmann et al. 2010; Demirpehlivan et al. 2011; Dornhoffer 1997, 1999, 2003). It appears that, compared to fascia, cartilage grafts can be expected to provide equivalent hearing results with an increased efficacy and durability of repair.
The major disadvantage associated with cartilage reconstruction of the TM is that the TM is essentially opaque following the surgery. Therefore, assessment of the middle ear can be challenging as middle ear effusions or residual cholesteatoma cannot be visualized with otoscopy. Furthermore, following cartilage tympanoplasty, tympanograms are unreliable and usually will reveal a low-volume type B curve regardless of middle ear status. Therefore, the hearing result is the best indicator of middle ear status. In some cases a CT scan may ultimately be needed to examine the middle ear space. If it is determined that a ventilation tube is necessary, intubation through the cartilage is often difficult and usually requires a general anesthetic. Fortunately, revision surgery following cartilage tympanoplasty is relatively straightforward. The tympanomeatal flap can be raised easily in the standard fashion, and adhesions and scarring appear to be less common than with other graft materials.
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