Pediatric Otologic Surgery

Middle Ear and Mastoid Surgery

Chronic Suppurative Otitis Media and Tympanic Membrane Repair

A number of factors are thought to influence the success of tympanic membrane repair in chronic suppurative otitis media (CSOM), such as age, type of graft material, and surgical technique. Several published meta-analyses have tried to elucidate the importance of these factors.

The optimum age at which to perform tympanoplasty is an ongoing point of discussion. Smaller case series are often underpowered to detect any effect of age on outcome, whereas meta-analyses, typically of retrospective case series, seem to suggest that successful closure of tympanic membrane perforation is more likely in older children. Vrabec and colleagues reported an improvement in closure rate in older children, as did Tan and colleagues. However, Hardman and others found that there was no relationship between age and closure rate. Of interest, perforation closure rates were significantly lower in children younger than the index ages of 9, 13, and 15 years, but no significant difference was found with other index ages. They concluded that the presence of a healthy contralateral ear was a more reliable predictor of successful outcome than age alone, but of course, middle ear status is not independent of age, as young children are more likely to have middle ear effusions. Additional factors such as adenoid hypertrophy, immature eustachian tube function, and higher incidence of acute otitis media (AOM) might also contribute to worsened outcomes in younger children. The alternative to surgical repair is watchful waiting, which may require water precautions. In our experience, we delay surgery until the child is around the age of 10 years old, at which point the child often prefers the option of surgery to continued water precautions. Earlier surgical intervention is reasonable to consider if the child has troublesome otorrhea or hearing loss.

Cholesteatoma

Acquired cholesteatoma is much more common than congenital cholesteatoma, even in children. It most commonly presents around the age of 10 years, but even children aged 3 or 4 years old can present with extensive disease and bone erosion. It is unknown why some cases of cholesteatoma arise so early in life, whereas others do not present until late adulthood, but the pathogenesis appears to be multifactorial. In our experience, cholesteatoma is not necessarily a consequence of otitis media in younger childhood and neither are tympanostomy tubes preventative. Poor eustachian tube function is assumed to be contributory and likely explains the well-established association with a cleft palate. ^, Underdevelopment of mastoid pneumatization is an almost invariable finding in acquired cholesteatoma and somewhat surprisingly, in congenital cholesteatoma as well. Several reports have shown that mastoid volume is smaller in patients with congenital cholesteatoma compared with normal controls, and cholesteatoma may recur and progress from postoperative retraction in congenital and acquired cholesteatoma alike. ^, A greater understanding of the factors that contribute to cholesteatoma formation is needed to help predict the risk of recurrent disease and guide surgical decision making.

Although often challenging to achieve, the ultimate goal of surgery for children with chronic middle ear disease is to achieve a self-cleansing, waterproof, cosmetically normal ear with permanently normal hearing. Many factors specific to children must be considered to select an appropriate surgical approach and to optimize outcomes. In addition to the long-standing controversy of canal wall up (CWU) versus canal wall down (CWD) surgery, the surgeon may consider mastoid obliteration or, alternatively, a minimally invasive endoscopic approach.

Canal Wall Up Versus Canal Wall Down Mastoid Surgery

Although meta-analyses of surgical outcomes in adults with cholesteatoma have demonstrated a lower rate of recidivistic disease after CWD compared with CWU surgery, ^, we continue to favor CWU surgery in children. An open mastoid cavity commonly requires regular debridement and topical treatment to keep it clean and dry. Many children find cavity maintenance unpleasant or intolerable, which may necessitate general anesthesia for proper debridement. Additionally, the associated meatoplasty may be problematic in terms of cosmesis, water entry, and the fitting of a hearing aid mold. There may be an increased likelihood of requiring a second stage of surgery after a CWU approach, but it is important to recognize that CWD procedures may also require revision surgery 17. The robust regrowth of mastoid cortical bone in children may compromise adequate access through the meatoplasty. Furthermore, the need for second stage CWU procedures may be reduced by more complete disease removal (through the use of endoscopes and the KTP laser ) and by surveillance using nonechoplanar diffusion-weighted magnetic resonance imaging (MRI). ^,

CWD surgery may be appropriate as the initial procedure in select circumstances, which constitute approximately 10% of our cases. When the mastoid is constricted such that a front-to-back technique creates a small residual cavity, it may be easier to debride a small mastoid cavity accessed by a meatoplasty compared with a postsurgical CWU ear with a narrow meatus. Other considerations leading to a CWD approach may be parental or patient reticence to undergo a second surgical procedure, concerns about adequate access to follow-up, or poor fitness for anesthesia. We disagree that a CWD approach is mandatory for children with an only hearing ear, labyrinthine fistula, or bilateral cholesteatoma. ^,

Mastoid Obliteration

As discussed previously, both CWU and CWD surgery may present postoperative problems, whether related to the difficulty of maintaining a clean open cavity or hygiene issues to ingrowth of recurrent cholesteatoma after CWU. Obliteration of the mastoid space or attic alone may improve outcomes in children from an unacceptably high revision rate of around 15% to 20% with CWD and CWU mastoidectomy alone ^, ^, to a rate of 2% to 3% at 5 years, respectively. ^,

It is hypothesized that obliteration of the mastoid air cells after CWU surgery prevents recurrence by eliminating gas absorption by the mastoid mucosa, facilitating maintenance of normal middle ear pressure. From a practical perspective, successful obliteration of the mastoid eliminates the space into which cholesteatoma could regrow. Obliteration can be performed at the time of the primary surgery or as a secondary procedure for the management of recurrent disease or a troublesome cavity. Autologous bone pate (a mixture of bone dust and blood) is a commonly used material, ^, which has been shown to be effective in children. ^,

Totally Endoscopic Ear Surgery for Cholesteatoma

Techniques and equipment have developed to allow an increasing proportion of otologic surgeries to be completed through the ear canal, without an external incision, using a totally endoscopic approach. Children and their parents enthusiastically embrace the opportunity to have surgery seemingly without an incision. In our growing experience, the lack of an external incision reduces surgical time, temporary asymmetry prominauris, and hyperesthesia and postoperative pain, enabling earlier discharge from hospital and return to normal activities.

It has previously been demonstrated that endoscopic inspection of areas such as the sinus tympani after microscope-guided dissection reduces the risk of residual cholesteatoma. ^, In children, the use of the endoscope to guide dissection in the middle ear has been shown to further reduce the risk of residual disease beyond using it for inspection postmicroscopic dissection. Current evidence for totally endoscopic ear surgery (TEES) does not demonstrate a significant reduction in residual rates over open mastoid surgery. As of yet, few centers have gathered sufficient experience to be able to determine whether TEES alters recurrence rates, although some suggest that it might have a beneficial effect. The endoscope may be particularly useful to assess middle ear ventilation pathways, which can contribute to recurrent pars flaccida retraction pockets; however, acquired pediatric cholesteatoma is predominantly pars tensa in origin. As the endoscope enables improved access to the medial epitympanum under an intact ossicular chain, it may allow clearance of the cholesteatoma without disruption of the chain, preserving better hearing. Otherwise, hearing results are assumed to be comparable to those of microscope-guided ossiculoplasty. Even if recidivism rates and hearing thresholds are not improved by TEES, the reduction of morbidity, avoidance of wound complications, and the greater potential to maintain normal anatomy are significant benefits to both child and parent. As TEES becomes more widely adopted, it is likely that better long-term data will become available.

Hearing Rehabilitation and Cholesteatoma

As acquired cholesteatoma is twice as likely to originate from the pars tensa than from the pars flaccida in children, the long process and stapes suprastructure are frequently affected early in the disease process. The resulting moderate unilateral hearing loss may have significant long-term implications. Two studies assessing quality of life in adolescents and younger children with unilateral hearing loss found effects similar to those of bilateral hearing loss; interestingly, these studies suggested that hearing aids may not improve quality of life for these age groups. ^, Although these studies included children with sensorineural hearing loss (SNHL) and were not specific to the acquired hearing loss of pediatric cholesteatoma, they did illustrate the dichotomy between expectant management of hearing loss versus rehabilitation in this age group. Many of our teenage patients seem to cope well with a unilateral moderate conductive hearing loss and decline the opportunity of rehabilitation with hearing aids or ossiculoplasty.

A variety of materials and techniques of ossiculoplasty have been reported in children, ranging from autologous material such as incus interposition to partial (PORP) or total (TORP) prostheses. An incus interposition typically yields better hearing results compared with a fascia myringostapediopexy, with normal hearing achieved in 75% of ears. Our retrospective data suggest equally good hearing outcomes with cartilage myringostapediopexy, which may also mitigate subsequent tympanic membrane retraction. Results with PORPs and TORPs are often reported together, but a meta-analysis (which includes adult patients) and a reasonably large pediatric series show that PORPs generally provide better hearing outcomes than TORPs. ^, Long-term hearing results after TORP are disappointing, with only around one third of ears having good hearing thresholds after 5 years. Thus preservation of the stapes suprastructure is an important determinant of good hearing outcome, and evidence suggests that preservation of the malleus is even more important. In summary, as children and adolescents do not achieve acceptable results from TORP and are not enthusiastic hearing aid users, the best hope for good hearing after cholesteatoma surgery is a functionally normal external and middle ear, or at the least, preservation of the stapes suprastructure and tympanic membrane.

Bone Conduction Devices

The bone conduction device (BCD) is a well-established method of hearing rehabilitation, which can be used in pediatric patients with conductive, mixed, or single-sided hearing loss, particularly those who are unable to wear conventional hearing aids. In contrast, the most common indication for BCDs in adults is single-sided deafness (SSD). The rehabilitation of microtia and external auditory canal atresia is addressed in Chapter 19 .

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