11 TOTAL TYMPANIC MEMBRANE RECONSTRUCTION
Andrew J. Fishman
See Video Demonstration Below
INTRODUCTION
Many techniques have been described for repair of tympanic membrane perforation and often the decision as to which technique to employ is made during the procedure. The site of the perforation, size of the perforation, the condition of the eustachian tube, and surgeon’s experience all influence the decisions.
The extent of a tympanic membrane defect is judged at the outset of surgery, including any additional loss of area that may result from removal of the disease, extirpation or excision of the mucocutaneous junction (i.e., rimming).
There are three tiers of complexity when deciding upon which technique should be used to reconstruct the tympanic membrane.
- Limited Central Perforations: defects amenable to a standard underlay technique
- Marginal Perforations: typically reconstructed by underlying the grafting material, accompanied by a mico-rotational flap of annular elements in conjunction with the adjacent skin of the canal wall
- Total Tympanic Membrane Reconstructions (TTMRs): total or subtotal defects that require more creative advanced techniques
Limited central perforations can be easily managed with a standard underlay technique. For the more complex and larger marginal defects, I have described strategies using a “zone-based approach,” which serves as a model for planning and execution. There are, however, still a significant number of patients who have scarce residual tympanic membrane, or adherent keratin matrix involving the undersurface of the tympanic membrane requiring sacrifice. These situations prove poor for either standard underlay or the zone-based techniques. Other techniques involving grafting lateral to the tympanic annulus have been described to better manage these situations. However, these techniques can result in delayed epithelialization of exposed canal wall bone and mucosalization of the neotympanum. Techniques that involve grafting lateral to the tympanic annulus may also result in intratympanic cholesteatoma formation. Repair of large perforations involving and including the anterior segment additionally predisposes to anterior blunting, as well as lateralization of the graft. The total tympanic membrane reconstruction technique was developed specifically to avoid these complications, as well as to facilitate extirpation of the more extensive inflammatory and neoplastic pathologies commonly encountered, and yet still amenable to intact canal wall mastoidectomy approaches.
HISTORY
Much of the patient’s history will relate to the primary disease process itself. The procedure of TTMR is indicated not only for surgeries of primary tympanic membrane repair but also for cholesteatoma and other pathologies of the middle ear and mastoid in which much of the tympanic membrane will need to be removed in order to best extirpate the disease. Examples include paraganglioma that has expanded beyond the middle ear into the external canal, leaving no usable membrane elements for other reconstructive purposes. Another example of the utility of this technique is for revision of prior failed tympanoplasties that have either resulted in severe stenosis or stricturing, or widespread mucosalization of the neotympanum and most medial canal wall.
There are also certain historical factors that should be noted, and counseling should reflect this. One salient example that comes to mind is the situation often encountered in relation to patients who have acquired a stenotic ear canal secondary to inflammatory disease. I have found that the results in these patients is less than ideal and that they tend to restenose at a greater rate than those with either trauma or chronic otitis media and cholesteatoma. The reason for this observation is not entirely understood, but I suspect that the underlying physiology of the tissue in the patients who suffer from these issues may adversely impact the healing process as well.
TTMR was developed to completely reconstruct the tympanic membrane using a combination of anterior canal wall free skin graft, split-thickness skin grafts taken from the postauricular incision, and a scaffold of either temporalis fascia or other adequate substrate. The technique also relies on stenting the anterior canal wall. The technique differs from lateral onlay techniques in that the entire fibrous annulus and fibrous tympanic membrane remnant need not be retrained so that complete access to the middle ear cavity can be accessed and/or reconstruction can be performed in any circumstance where the canal wall is kept intact. The procedure can be performed with any combination of ossicular chain and with either immediate or delayed ossiculoplasty and/or cartilage tympanoplasty.
PHYSICAL EXAMINATION
A careful examination of the ear with the office microscope is imperative. This examination is the cornerstone of disease identification, and excessive reliance on radiographs would be considered an inadequate approach. Particularly in patients with prior surgery, the condition of the external auditory canal skin with regard to mucosalization, areas of deficient anterior canal wall bone, and the presence of acute infection and or colonization with fungal elements are important to note, as these factors may require modification of the technique or predispose to poor outcomes. If clinically possible, it is ideal to get these factors optimized prior to definitive reconstruction. The technique of TTMR as described in this section is specific to intact canal wall surgeries. Any physical examination findings, which would suggest the possibility of open cavity surgery, should prompt appropriate preoperative counseling.
Formal audiologic testing of the hearing is imperative prior to any proposed surgery. Patients without serviceable hearing may benefit from alternative strategies.
INDICATIONS
Indications for TTMR include total perforations of the tympanic membrane, large subtotal perforations with full anterior marginal extension, subtotal perforations with mucosalization or refractory granular inflammation of the tympanic remnant, or cholesteatoma involving a significant portion of the undersurface of the TM. TTMR is indicated in any intact canal wall procedure in which there is no other tympanic remnant, which could be used to perform alternative techniques as previously discussed.
CONTRAINDICATIONS
Relative contraindications for surgery are based largely on medical comorbidities and/or stable longstanding dry perforations with little or no impact on perceived quality of life in elderly patients, and/or a patient’s desire not to undergo elective treatment. This assumes a fair presentation of the risk benefit ratio and compliance with conservative measures, including dry ear precautions and appropriate monitoring. TTMR is used in specific conditions as outlined and not indicated in defects more appropriately treated with alternative methods with appropriate risks and benefits weighed. Because TTMR involves a more extensive restructuring of the tympanic membrane and external auditory canal, it would be considered relatively contraindicated in cases whereby an alternative approach would be more appropriate, as discussed in other sources in the recommended reading.
PREOPERATIVE PLANNING
The standard radiographic analysis performed in most cases will be limited to conventional thin section noncontrast axial and coronal CT. The intention is to assess the extent of disease and sequelae of prior surgeries. I use 0.5-mm sections in two planes (axial and coronal) expanded views. MRI is added as deemed necessary, depending upon the primary pathology and is useful in determining dural involvement. Carefully performed ear microscopy and audiometric testing is performed in all patients undergoing ear microsurgery.
SURGICAL TECHNIQUE
FIGURE 11.1 A. Transcanal schematic of free graft harvest incisions and Koerner flap. B. Cross-sectional schematic of incision placement. A single arrow demarcates the lateral free skin graft harvest incision placed at the bony cartilaginous junction. Double arrows demarcate long pedicled Koerner incisions.
Postauricular access to the external auditory canal is provided through a long Koerner flap taken just lateral to the posterior tympanic annulus. This flap will provide a vascularized pedicle to the forming neotympanum. Care is taken to remove any mucosalization at the distal tip of the flap that may eventually grow onto the underlying graft. Neither the annulus nor any residual TM remnant is included in this flap (Fig. 11.1A, double arrow).
The anterior canal wall skin is harvested as a free graft. A lateral incision is made at the level of the bony cartilaginous junction so that the maximum available size is provided (Fig. 11.1B, single arrow). A medial incision is made just lateral to the annulus so that no mucosa cells are included in this segment. The residual TM and annular remnant are not included. Adequate size is achieved by the extreme lateral position of the anterolateral incision that is placed at the bony cartilaginous junction.
All residual TM remnants are removed, including the annular ligament. Similar to the case with traditional lateral onlay grafting, this technique does not allow the mucosa-lined TM undersurface to be placed atop the graft material, thereby minimizing the complication of neotympanic mucosalization and “wet ear.” Unlike traditional lateral onlay, the tympanic annulus is not preserved. The tedious removal of the keratinized epithelium from its surface is bypassed, and the inherent predisposition to intratympanic
FIGURE 11.2 A cross-sectional schematic of canalplasty. The cross-hatched area represents the region of bone removal. The arrow denotes the resultant anterior ledge.
FIGURE 11.3 A. Transcanal schematic of tympanoplasty graft placed with notch for malleus handle. B. Cross-sectional schematic of same. C. Transcanal schematic demarcates position of free-skin and split-thickness skin grafts.
postoperative cholesteatoma formation is avoided. In many instances, the additional exposure that is provided by minimally widening the annular ring into the hypotympanum and posterior mesotympanum, without regard for annulus preservation, is useful for complete exenteration of disease. If needed, additional widenings can be reconstructed easily with tragal or conchal cartilage.
A generous canalplasty is mandatory (Fig. 11.2, cross-hatched area). The intent of the canalplasty is not only to provide maximum visibility for transcanal middle ear dissection but also to create a less acute anterior, as well as inferior angle and to create an anterior shelf upon which to apply the rigid silicone stent during external canal packing (Fig. 11.2, arrow). Creating a generous inferior canalplasty eliminates the acute inferior canal–to-neo-tympanic angle, thereby maximizing the surface area of the neotympanum and theoretically improving the neo- tympanum to footplate area ratio–dependent sound pressure amplifier.
Grafting is performed with a large teardrop-shaped graft of either temporalis fascia or alternative suitably sized material, long enough to drape partially onto the anterior canal wall, as well as completely up the posterior canal wall (Figs. 11.3A,B and 11.4A).
The middle ear is filled with small cut squares of gelfilm to maintain a middle ear space. At this point, primary ossiculoplasty is performed in appropriate cases using conventional techniques.
The free anterior wall skin graft is placed, as in Figure 11.3C, and so that it bridges both the canal wall bone and covers the exposed malleus handle (Fig. 11.4B and C). Split-thickness skin grafting from the postauricular wound edge is used to resurface any accessible exposed bone of the external auditory canal (Figs. 11.3C and 11.4D).
Once the free-skin and split-thickness skin grafts are in position, the anterior silicone stent is placed. Care is taken to secure the stent against the shelf created during the canalplasty (Fig. 11.5A and B).
The Koerner flap is replaced onto the posterior graft, and the external auditory canal is packed with antibiotic-soaked cotton gauze strips introduced along the anterior silicone stent to act as a rigid unit during the healing period and thereby minimize the risk of graft lateralization. However, prior to replacement of the Koerner flap, it is helpful to introduce a small strip of gauze to secure the silicone firmly against the anterior canal wall and wedge it securely against the anterior angle (Fig. 11.6).
An appropriate cephalosporin or quinolone antibiotic (in cases of cholesteatoma) is given for 14 days postoperatively.
POSTOPERATIVE MANAGEMENT
The external auditory canal packing is removed 3 weeks postoperatively, with the exception of the silicone stent. This wound is repacked with 1/8-inch cotton gauze strips coated with a mixture of antibiotic, antifungal, and corticosteroid preparations. The pack is left in place for another 3 weeks, after which time all material, including the silicone stent, is removed and the ear is examined. If epithelialization is nearly complete, Gelfoam is applied focally. Additional cotton gauze packing is placed only if required, and an additional 3 weeks is allowed to pass. In younger patients or rare instances of local intolerance to the packing materials, the interval of exchange may be shortened to 2 weeks or even weekly.
FIGURE 11.4 Placing temporalis fascia (A); introduction (B) and final placement (C) of anterior canal skin segment; placing segments of split-thickness skin grafts (D).
FIGURE 11.5 Cross-sectional (A) and transcanal (B) schematic of proper placement of silicone stent.
Otic drops are administered throughout the postoperative course, beginning after the mastoid dressing is removed and continuing until complete epithelialization has occurred and all packing is removed.
FIGURE 11.6 A small cut segment of antibiotic-soaked umbilical tape is wedged against the silicone stent to secure it up against the anterior canal wall and prevent it from dropping back just prior to replacement of the Koerner flap. Before (A) and after (B) placement.
COMPLICATIONS
Early experience reported with the technique yielded a 92% success rate with regard to a well-healed intact tympanic membrane. Patients who experience limited reperforations may be repaired with a simple underlay technique. I have seen a very small number of patients who were operated during refractory states of infection generate a heightened granulation response to the indwelling packing material. This can typically be remedied by laser ablation and debridement with reintroduction of fresh packing materials.
A small number of patients, particularly elderly individuals and smokers have not been able to fully epithelialize over the neotympanum after an extended period of time, in the order of 3 months of more. In these cases, I have found that a laser tympanolysis with debridement of the superficial layer of nonviable tissue and placement of a small split-thickness skin graft taken from the posterior pinna will usually result in complete epithelialization and healing.
Because, the TTMR technique in principal does not introduce any mucosal elements lateral to the graft, mucosalization is very unlikely.
RESULTS
The primary grafting material used in TTMR is autologous temporalis fascia. In revision surgeries where sufficient fascia was not readily available, I used allograft dermis as a substitute with good results. The success of autologous temporalis fascia as a grafting material is well documented in the literature for perforations of various extents utilizing a wide range of techniques. In general, success rates of more than 90% can be achieved, regardless of the surgical technique employed. Successful closure was documented by Kartush et al. in 120 patients at 6-month follow-up who were undergoing an over–under technique; however, 12 patients developed late TM perforations. Singh et al. showed similar results (93.3% closure rate) using an overlay and underlay technique in 60 patients with dry subtotal perforations secondary to chronic suppurative otitis media. However, Khan et al. reported a TM closure rate of 84% at 5-year follow-up in 69 patients who underwent an underlay tympanoplasty with temporalis fascia. Similarly, Berger et al. showed a success rate of only 52.8% in revision myringoplasty patients. Of the failures, 39.4% were caused by complete no-take of the graft material. Rates of closure have been similar with dermal allografts. Fayad reported an 87.5% closure rate. Accordingly, it was important to demonstrate that the TTMR technique can achieve these levels of success without compromise.
TTMR differs from traditional lateral onlay in that the entire annular ligament is removed, along with any unusable TM remnants. It is characterized by an extreme lateral anterior free graft harvest incision, silicone stenting, and split-thickness skin grafting. The 92% overall closure rate obtained with TTMR by Fishman is comparable to those reported in routine cases using traditional techniques including patients with much smaller perforations. Of those patients grafted with available temporalis fascia, 97% were successfully closed. In this study, the overall postoperative air–bone gap was less than or equal to 20 dB in 89% of all patients undergoing TTMR. Sixty-six percent of patients achieved an air–bone gap of less than or equal to 15 dB. Fifty-one percent had an ultimate air–bone gap of 10 dB or less. This is a highly favorable outcome considering that TTMR is designed to address those severe cases without available TM.
The primary advantage of the TTMR technique is that it does not require any residual fibrous tympanic membrane or annulus. The technique can therefore be used in the most severe cases where no usable tympanic membrane remnant is present. This makes it particularly useful in the treatment of benign temporal bone neoplasms or revision chronic ear surgery with mucosalization extending lateral to the tympanic annulus, medial stenosis as well as postradiation changes. With removal of the annular ligament, access to the hypotympanum can be liberally extended by freely drilling down the bony annulus. The bony defect can be easily reconstructed with cartilage grafts taken from either the tragus or the conchal bowl. Because all the skin of the ear canal is removed and the canal liberally widened, there is ample room through which to work, making the technique ideal for extensive cholesteatomas and benign neoplasms of the middle ear and temporal bone (Fig. 11.7). With strict adherence to technical details, there should be no implantation of mucosal cells lateral to the graft, virtually eliminating the issue of postoperative mucosalization of the tympanic membrane (Fig. 11.8).
Disadvantages are primarily related to the sensitive nature of the technique and the duration of stenting. Although children may heal within approximately 4 weeks time, the typical expected time to complete healing may range from 6 to 9 weeks in adults. The silicone stent is left in place for up to 1 month in children and 4 to 6 weeks in adults for optimum healing. During this period of time, the patient requires changing of the external gauze packing every 2 to 3 weeks. The packing is well tolerated in most patients who are still locally insensate during this period of healing. The postoperative care requirements may also be a limitation for patients travelling from long distances. In these cases, alternative methods may be used, or arrangements can be made with suitably trained local physicians.
FIGURE 11.7 Postoperative CT scan demonstrating good anterior angle after TTMR procedure (arrow). Silicone is seen in the middle ear prior to second-look procedure for cholesteatoma (asterisk). This patient was lost to follow-up for 3 years and re-presented to the clinic, at which time this scan was obtained demonstrating the long-term success of the technique.
FIGURE 11.8 Postoperative otomicroscopy demonstrating well-vascularized and healed neotympanum (A) with good anterior angle (B) in a patient undergoing second look for cholesteatoma. Office ear endoscopy in a patient who underwent TTMR with intact ossicular chain. C. Dotted lines and arrows delineate well-formed anterior angle.
PEARLS
- Quality and extent of canalplasty is integral to the success of this technique. Although a certain degree of anterior blunting can occur with any technique, which involves the anterior aspect, inferior blunting can largely be eliminated by adequate reduction of the inferior canal hump, promoting the maximum surface area of the reconstructed neotympanum.
- Patience and counseling regarding the extended duration of postoperative packing is important. Packing materials are well tolerated by almost all patients. It is better to keep the packing material in longer than necessary, than to remove it too early, promoting unopposed accumulation of granulation and scar tissue. This may result in less than optimal outcomes.
- In cases of cholesteatoma, or when staged ossiculoplasty is anticipated, it is best to underlay a thin sheet of cartilage at the time of primary TTMR to serve as a support particularly for synthetic prostheses. A second look with ossiculoplasty can usually be performed by a transmastoid posterior tympanotomy approach obviating the need to disassemble the reconstruction.
- In cases of cholesteatoma, or when staged ossiculoplasty is anticipated, a sheet of silicone can be implanted in the middle ear. It is important to properly shape this material so that it can act as a rigid support and promote adequate middle ear volume and prevent collapse of the mesotympanum. The construct should exit through the facial recess into the mastoid so it can be extracted without disruption of the neotympanum.
PITFALLS
- The TTMR technique requires rigid and firm packing from the external canal with proper placement and positioning of the stents and skin grafts. When no silicone is left in the middle ear, it is important to use a material that will withstand the compression. I use layered gelfilm, which expands and is less compressible than gelfoam alone. If gelfilm is unavailable, then it is important to limit the pressure applied from the external packing as not to overly compress and collapse the middle ear.
- TTMR is equally successful in adults and children. In young children, it is important to plan the placement of nonabsorbable material in such a manner that it can easily be extracted in the office setting. Rather than using very small pieces of antibiotic soaked umbilical tape for the initial securing of the silicone stent, I first place a dried piece of gelfoam to direct the silicone stent up against the anterior canal wall. I then use only two segments of umbilical tape so that neither is too deep within the canal to be able to extract then in an uncooperative child. Fortunately, the healing potential is accelerated in children so that only one or two packing changes are needed in the clinic. The interval may be shortened in the young child to a total of only 4 weeks for the stent with a single packing change. If the child is uncooperative, it is advised that an examination under masked general anesthesia be performed to adequately care for the postoperative ear. This, however, should be an uncommon occurrence.
- Be cautious to avoid overly aggressive anterior canalplasty with exposure of temporomandibular joint (TMJ) adipose tissue. If a small area of the bone is taken down to the fibrous capsule, there will typically be no adverse effects. However, if a significant area of bone is violated or adipose tissue exposed, then there may be significant anterior blunting because of exuberant granulation in the area from the constant irritation caused by the movement of the TMJ in the area. If a small amount of adipose tissue is exposed, then a simple bipolar cauterization of the out pouching may prevent the formation of the granulated tissue.
- Delayed epithelialization can occur but can usually be remedied with tympanolysis and/or local application of split-thickness autografts for completion of healing.
- Epithelialization is promoted by adequate overlapping of the elongated Koerner flap onto the grafting material. In cases where the disease has resulted in a foreshortening of this flap, overlap can be optimized by tacking the base of the flap to a tie down hole made using a 1-mm burr through the lateral aspect of the posterior canal wall, effectively advancing the flap medially. This is particularly useful in younger children.
INSTRUMENTS TO HAVE AVAILABLE
- Otologic surgery set
- Silicone sheeting cut to shape and size. Thickness 0.04 inches (1 mm)
- Umbilical tape gauze used as packing strips. Impregnated with antibiotic ointment.
Acknowledgment
I would like to acknowledge the contribution of Dr. Jozef Mierzwinski, MD, Chairman of Otolaryngology at the Children’s Hospital in Bydgoszcz, Poland, in the preparation of this manuscript. His expertise and friendship is greatly appreciated. He has also been a coauthor on a number of related publications listed in the suggested readings.
SUGGESTED READING
Rizer FM. Overlay versus underlay tympanoplasty. Laryngoscope 1997;107:1–36.
Kartush JM, Michaelides EM, Becvarovski Z, et al. Over-under tympanoplasty. Laryngoscope 2002;112:802–807.
Fishman AJ, Mierzwinski J. The zone-based approach for selection of tympanoplasty technique. Otolaryngol Pol 2012;66(1):12–19.
Fishman AJ, Mierzwinski J. Myringoplasty/tympanoplasty—zone based approach & Total Tympanic Membrane Reconstruction (TTMR). In: Kountakis SE, ed. Encyclopedia of otolaryngology, head and neck surgery. Springer, 2013.
Roland, J. T., Jr.. Master Techniques in Otolaryngology Head and Neck Surgery. Wolters Kluwer Health, 20180501. VitalBook file.
The video below demonstrates the basic principles and technique of TTMR (Total Tympanic Membrane Reconstruction.)
This short video below demonstrates how the TTMR can be used after removal of a large cholesteatoma with the canal wall up posterior tympanotomy technique. The surgery is in a child with extensive cholesteatoma and involvement of the entire tympanic membrane and ossicles. All the affected structures were removed and the stapes was left intact and cleaned of the disease. A second delayed stage is planned to explore for recurrence and the TTMR technique is used to rebuild the entire ear drum. The use of TTMR is an excellent adjunct to cholesteatoma surgery because it allows for a wide unimpeded vews and access to the middle ear which expedites intact canal wall techniques. With intact canal wall procedures, there is no mastoid cavity to care for in the future and the ultimate hearing outcomes tend to be superior, so they are the preferred technique when technically feasible.