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Volume 6, Number 3, 2002
Cricothyroidopexy in Male-to-female-Transsexuals – Modification of Thyroplasty Type IV
Kerstin Neumann, Cornelia Welzel and Alexander Berghaus
HNO-Klinik der Martin-Luther-Universität Halle-Wittenberg
Magdeburger Str. 12
06112 Halle
Germany
Citation: http://www.symposion.com/ijt/ijtvo06no03_03.htm
After adapting the primary sex characteristics, the raising of voice pitch should be an option offered as part of male-to-female transition. Hormonal treatment is not capable of raising voice pitch, and logopedic treatment on its own cannot, as a rule, guarantee lasting success. Since 1993, a modified cricothyroidopexy via miniplates, following Isshiki’s technique, has been performed at the ENT Department of the Martin-Luther University of Halle-Wittenberg. This procedure is based upon an approximation of the cricoid and thyroid cartilages resulting in an increase in the vocal cord tension. Combined with a chondrolaryngoplasty it allows for a reduction of the laryngeal prominence. So far 67 patients have undergone this surgical intervention. Laryngoscopy and a detailed voice diagnostics, as well as ultrasound and computer-tomographic examinations of the larynx are performed pre- and post-operatively in order to record the anatomical, physiological and functional data. So far good functional results have been achieved showing an average increase of the fundamental frequency by approximately five semitones.
Keywords: transsexualism, phonosurgery, logopedic therapy
The secondary sex characteristic of the larynx with its vocal function remains a major obstacle to male-to-female transsexuals ‘passing’ as female. This is because, in contrast to the situation of female-to-male transsexuals, hormonal treatment does not have any substantial or lasting influence on voice pitch, and logopedic therapy on its own does not produce satisfactory results. In everyday life, after transitioning, a transsexual woman, who in her appearance and her legal status lives as a woman, will often continue to be identified as a man because of her voice, thus hindering her social assimilation.
An operative intervention to raise the voice pitch of the patients is designed to enable them to integrate into their social environment in a better way. Voice adaptation in these patients improves their sexual identity, their body image, their self esteem and their general well-being (Wolfradt and Neumann, 2001). Thus the development of a standardised concept for raising the voice pitch of male-to-female transsexuals, including well-defined pre- and post-operative diagnostics, is of importance to improve quality of life in their new gender role. Most of the patients also request a reduction of the laryngeal prominence, (i.e., the Adam’s apple, which is typically male). It is for this reason that after the change of the primary sex characteristics, phonosurgery should be included in the therapeutic concept of the transformation of the secondary sex characteristics.
Authors such as Isshiki (1989), Wendler (1990), Gross and Fehland (1995), Le Jeune et al. (1983) or Tucker (1985) have so far described a variety of operation techniques for raising voice pitch. Basically, this aim can be achieved either by reducing the vibrating vocal cord mass, by shortening the vocal cords, or by increasing the vocal cord tension.
The present article presents the cricothyroidopexy via miniplates in order to raise voice pitch, following Isshiki’s technique, as developed at the Department of Otorhinolaryngology, Head and Neck Surgery, Martin-Luther University of Halle-Wittenberg. This method can be expected to produce a lasting rise in the voice pitch of patients.
Following Isshiki’s technique (1989), which is based upon the approximation of the cricoid and thyroid cartilages in order to achieve an increase in vocal cord tension, and thus a rise of the voice pitch, we have been performing a modified cricothyroidopexy via miniplates at our ENT department since 1993 (Figure 1).
Figure 1. Operation principle according to Berghaus and
Neumann (1996)
This method avoids interference with the inner structures of the larynx and can be reversed. In the case of typically male laryngeal prominence, the intervention is combined with chondroplastic surgery according to Wolfort et al. (1990) to decrease the laryngeal prominence. In this case, a strip of cartilage is excised in the area of the upper laryngeal prominence prior to the cricothyroidopexy (Figure 2).
Figure 2. Adam’s apple reduction plastics according to Wolfort (1990)
The operation principle consists, as described by Isshiki (1989), in an approximation of the cricoid and thyroid cartilages. First a skin incision of a minimal length of 2cm is made in a throat fold above the larynx. After the preparation of the thyroid and cricoid cartilages, the approximation is obtained in the following way: after pricking the cricoid cartilage, the needle is passed under the cricothyroid membrane into the thyroid cartilage, and again out of it on the same side in order to be passed beside it into the thyroid cartilage and again out through the cricoid cartilage (principle of back-stitch suture). When required, two of these sutures can be performed. When the wire suture is tightened and fixed, both cartilages are ventrally approximated to a maximum degree. In order to avoid failures through a rupturing of the cartilage with later loosening of the suture, as often described by Isshiki, we modified the technique by passing the 2-0 monofile wire sutures over three-hole or four-hole miniplates, either resorbable (made of Lactosorb®) or non-resorbable (made of titanium) and fixing them (see Figure 1) Berghaus and Neumann, 1996; Neumann and Berghaus, 1996a; Neumann and Berghaus, 1996b). The approximation is continued until the maximum contact of the two cartilages has been achieved, which may be supported by minimum resection of the tissues between the two cartilages. As a rule, the operation is done under intubation anaesthesia in order to avoid major psychic and physical strain for the patients during the intervention, resulting in increased restlessness. This is particularly advantageous for elderly patients, since they often show massive ossification of the thyroid cartilage which may require a more forceful placing of the wire structures or even some drilling. However, local anaesthesia is also possible. The advantage of the latter is the chance of intraoperative checking of the speaking voice pitch (Neumann and Berghaus, 1996a; Neumann and Berghaus, 1996b).
The result of the approximation of the thyroid and cricoid cartilages is an increased tension in the vocal cords and thus a rise of the voice pitch. When the operation is carried out with due care, the endolaryngeal structures remain unimpaired.
Between October 1993 and December 2001, 67 patients with an average age of 40 years underwent this surgical intervention.
Pre-operatively the fundamental frequency was within the male (< cis) or indifferent (d-e) range, which can be regarded as an indication for operation. None of the patients was able to suppress the male timbre despite previous logopedic therapy. The patients assigned for the operation were submitted to detailed voice diagnostics pre- and post-operatively as well as after one week, four weeks, twelve weeks and one year in order to record the long-term results. This includes, apart from laryngoscopy, an auditive assessment of the voice, its fundamental frequency and a description of the voice sound, the measurement of the voice scope as well as a computerized voice analysis (Kay Elemetrics Computerized Speech Lab = CSL). Additionally the larynx is examined pre- and post-operatively by means of ultrasound and by means of spiral computer-tomography (CT). These examinations serve to assess the distance between the cricoid and thyroid cartilages as well as the length of the vocal cords. Spiral computer-tomography allows for a complete presentation of the laryngeal structures. Using definite parameters such as breathing conditions and by adjustment of instruments reproducible and compatible investigations can be carried out (Bunke, 1998; Galanski and Prokop, 1998).
Logopedic voice training for a duration of at least three months supplements the therapy. During this time, the patients should practice and thus stabilise their new female voice.
The post-operative follow-up examination period can last from one month and to seven years. A comparison between the pre- and post-operative voice pitch values revealed that the fundamental frequency could be raised by one fourth on average – approximately five semitones – ranging from one semitone to more than one octave. While no patient pre-operatively showed a speaking voice pitch within the normal female range, nineteen patients (28 %) did so post-operatively. Twenty-six patients were in the indifferent spectrum between male and female normal frequencies (39 %), whereas pre-operatively there were only six. (Figures 3 and 4). A temporary post-operative hoarseness, which was noted in almost all cases, was no longer apparent four weeks after surgery.
Figure 3. Comparison of pre- and post-operative voice pitches
Figure 4. Voice pitch rise in semitones
The great majority of the patients (80%) attained an ‘inconspicuous’ voice pitch within the observation period. In their daily life, their voices are often accepted as female voices, even over the telephone. A lowering of voice pitch occurred only in a few cases, or the patients were dissatisfied because of an insufficiently raised voice pitch. For these 2 reasons, 9 patients out of 59 underwent revision surgery after an average period of 13 months. The wire sutures of 6 patients had to be retightened. Retightening was impossible in 4 patients due to massive scarring in the operation area. In these cases, the suture material was removed. One patient asked for removal of the titanium plates, wishing to reverse the operation due to personal misgivings.
In six of the nine patients who underwent revision surgery, no further increase of the fundamental frequency was achieved, whereas the other three patients showed a increase of one to two semitones. Pre- and post-operative computer-tomographic examinations revealed that the vocal cords were lengthened on average by 5mm through increased tension produced by cricothyroidopexy (Figures 5a and 5b).
Figure 5a. Spiral CT of larynx, pre-operative vocal cord length
Figure 5b. Spiral CT of larynx, post-operative vocal cord length. Prelaryngeal, operation-induced air inclusion
In addition, computer-tomography enables the maximum approximation of the cricoid and thyroid cartilages to be checked. The distance between the lower edge of the thyroid cartilage and the upper edge of the cricoid cartilage amounted to an average of 10mm preoperatively and 4mm post-operatively (Figures 6a and 6b).
Figure 6a. Spiral CT of larynx, 3D reconstruction. Face view of pre-operative thyroid and cricoid cartilages
Figure 6b. Spiral CT of larynx, 3D reconstruction. Face view of post-operative thyroid and cricoid cartilages. The distance between cricoid and thyroid cartilage is significantly smaller.
Good cosmetic results were obtained in all our patients by performing thyroid cartilage reduction plastic surgery, according to Wolfort (1990) (Figures 7a and 7b).
Figure 7a. Lateral view of laryngeal prominence – pre-operative
Figure 7b. Lateral view of laryngeal prominence – post-operative
With regard to the post-operative course of the therapy, there were no serious complications. In a few cases, the healing process was disturbed, this was due to infection or to the incompatibility of the suture material, which were then overcome. In these cases. healing was retarded, but was achieved in the end. Only one patient had severe delay in healing, which necessitated revision surgery with removal of the suture and plate material. In six cases (8.9 %) when healing, the skin moulded with the subcutaneous tissue, which resulted in scarred, cosmetically unsightly distortions of the cervical skin, especially during swallowing. Temporarily, 22 % of patients had swellings in the wound area as well as, in individual cases, small subglottic haematomas, which did not cause breathing impairment (3 %). These changes were completely absorbed within 14 days. In 10 % of patients, insignificant post-operative emphysemas were observed, which receded spontaneously within one week. On the whole, good cosmetic results, with only inconspicuous scarring, were obtained in the majority (90 %) of the patients.
The voice is an essential part of human identity. According to our patients, their voice constitutes the greatest obstacle to social assimilation and creating a new identity after completion of sex reassignment surgery (Berger, 1988). By the late 70s, the high degree of unease and discomfort experienced by male-to-female transsexuals with regard to their ‘male’ voice sound led to the development of phonosurgical voice pitch raising techniques (Kazatomo, 1979). It had become obvious that conservative procedures such as hormonal therapy or logopedic exercices alone can only be partially successful at best.
The basis of all operation techniques that have been developed so far is the physiology of voice production. This implies that, in analogy to the functioning of a musical string instrument, tone pitch can be varied by either changing the thickness of the vocal cords, their length, or their tension. This principle is the basis for all surgical techniques designed to raise the voice pitch that have been published so far. Wendler (1990) and Gross and Fehland (1995) prefer the deepithelisation of the vocal cords in the area of the anterior commissure, followed by suturing the tissues and by using fibrinous glue. This approach results in a shortening of the vibrating vocal cord parts. Moreover, this way, less mass is moved during the vibration process, which generally leads to an increase in the fundamental frequency. The disadvantage of this method is an increased lasting hoarseness after surgery, as well as a frequently irreversible narrowing of the lumen of the larynx. On the other hand, there is the advantage that the patients do not have any visible scars.
Through the anterior posterior lengthening of the thyroid cartilage at the level of the vocal cords, using a cranial pedicle cartilage flap, Tucker (1985) achieves an increase in vocal cord tension and thus a rise in the voice pitch. A similar technique is also used by Le Jeune et al. (1983), who increases vocal cord tension by means of a pedicle thyroid cartilage flap, which is tightened ventrally at the level of the vocal cords and fixed by means of a cartilage chip. Although the voice results are acceptable in this case, the larynx becomes distinctly prominent due to the ventral shift of the thyroid cartilage. The cosmetically unfavourable results make this method unacceptable to our patients .
By approximating the cricoid cartilage to the lower edge of the thyroid cartilage, Isshiki (1989) achieves an increase in vocal cord tension. The cricoid and thyroid cartilages are fixed to each other by means of sutures. On principle, the procedure of cricothyroidal approximation imitates the contraction of the cricothyroid muscle (vocal cord tensor) in this way raising the speaking voice pitch. This technique was first applied in women suffering from voice virilisation due to hormonal influences. As pointed out by Isshiki, the disadvantage of such a procedure is that no permanent results can be obtained as the fixation of the cartilage often ruptures. Indeed, our own experience confirms this risk. This is why in our modified approach, the cricoid and thyroid fixing wire sutures are twisted over titanium or absorbable miniplates. This obviously ensures that Isshiki’s failures due to rupturing of cartilages or their later loosening of sutures can be avoided over a very long period; therefore we use the term cricothyroidopexy.
Unlike Wendler’s (1990) or Gross and Fehland’s (1995) methods, our modified cricothyroidal approximation does not, when correctly applied, change the inner structure of the larynx. While the operation technique exclusively extends the vocal cords, it does not result in a stenosis of the glottis. In this way, risks for operations under intubation anaesthesia (the placing of the tubus might be made difficult because of a surgically narrowed glottis) that may be necessary in the future can be avoided. Since, unlike the methods mentioned earlier – with the exception of Isshiki – our technique does not affect the vocal cords, the danger of a post-operative irreversible hoarseness of the voice appears to be definitely smaller (Berghaus and Neumann,1996; Neumann and Berghaus, 1996a; Neumann and Berghaus, 1996b). It must be pointed out that a small cervical scar is inevitable, which however our patients did not mind this, given a normal healing process. Since the end of 1997, we have preferred using miniplates made from Lactosorb® rather than of titanium. This material has proven to be strong enough to stabilise the cartilages, and is completely absorbed after approximately one year – as could be seen during the revision operation. The advantage is a decreased amount of foreign material remaining in the body, though there is obviously no problem in combining wire sutures with titanium plates, in spite of the differences in the materials.
When choosing between local anaesthesia and general anaesthesia, we initially considered that local anaesthesia would allow for acoustic checking of the voice pitch rise intraoperatively, and so would avoid a too close approximation of the cartilages. However, when it became obvious that our patients invariably attempted to attain a maximum increase in voice pitch, the advantage of local anaesthesia was no longer relevant. In the case of distinct laryngeal prominence, Wolfort’s et al. (1990) chondrolaryngoplastic surgery, which cannot be performed without a cervical incision, may be done during the same intervention as the approximation of the cricoid and thyroid cartilages without any significant additional effort. A large Adam’s apple as a further male attribute puts such a great psychic strain on patients that thyreoid cartilage reduction plastic surgery should – if indicated and desired – always be included in the planning of the operation.
In 1998, examination methods like B-sonography and spiral computer-tomography of the larynx were first included in prediagnostics and phonosurgical procedures in our department. This allows an objective determination of the vocal cord length and of the distance between the cricoid and thyroid cartilages pre- and post-operatively. We are thus able to estimate the possible degree of voice pitch increase before the operation, and, post-operatively, to check the therapeutic result morphometrically, in addition to the auditive and computerised voice examination. Additionally, there is the possibility of determining the angle between the vocal cord attachment to the arytenoids cartilage (vocal process) and the anterior commissure of the thyroid cartilage as well as the change of the latter under maximum approximation. These investigations are presently only substantiated by a small amount of data, so that no definite tendencies can as yet be derived. In future, we hope to be able to predict the operation prognosis from the given individual anatomic conditions of the patient, that is, by an exact x-ray analysis of the larynx (Bunke, 1998; Galanski and Prokop, 1998).
The success rate of the method of treatment described above may be considered as very good when compared to the results reported in the pertaining literature. By means of glottal plastic surgery Mahlstedt and Gross (2000) were able to raise the fundamental frequency by an average of 8.5 semitones in 21 patients. Thus, in this smaller group of patients, a slightly larger increase was achieved; these patients remained hoarse to a higher degree, for a longer time, or as was usually the case, permanently.
Regarding the general results, especially the sound quality of the voice, the modified operation method according to Issikhi (1989) offers advantages in comparison to the endolaryngeal invasive techniques. An important part of the method is certainly the post-operative voice therapy without which the functional long-term results would be endangered (Berghaus and Neumann, 1996). The good functional voice results and the satisfactory cosmetic effect produced by the reduction of the Adam’s apple contribute to the patients’ psychic stabilisation. As shown in a study by Wolfradt and Neumann (2001), the surgical interventions enhance self-esteem, life satisfaction and the chance for social assimilation, at the same time strengthen gender identity.
Until now, ENT surgery and phoniatrics have only marginally occupied themselves with voice correction in male-to-female transsexuals. The patients concerned, who feel restricted in their female integrity by a deep ‘male’ speaking voice, and experience a high degree of discomfort and unease that cannot be relieved by conservative methods such as hormonal treatment or logopedic therapy alone. In most patients, these procedures only succeed insufficiently and temporarily. The modified cricothyreoideopexy with miniplates is an adequate surgical method to raise the fundamental frequency permanently. This is confirmed by the comparison of the pre- and post-operative voice parameters and the overwhelming post-operative satisfaction of the patients. Therefore, it is useful to include phonosurgery as an element of the therapeutic concept in sex ressignment. The development of a computerised evaluation of voice parameters and of diagnostic methods, like B-sonography and computertomography, could open a way for an individual prognosis of the raising of the voice pitch. The resection of the laryngeal prominence is an advantageous complement to surgery intended to raise voice pitch.
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Correspondence to kerstin.neumann@medizin.uni-halle.de