Location of the preepiglottic space and its relationship to the paraglottic space

Comparative Histoanatomy of the Epiglottis and Preepiglottic Space of the Lemur Larynx

OBJECTIVES

An adequate understanding of the evolution of the larynx presumably clarify the physiology and functional histoanatomy of the present-day human organ. This study investigated the comparative histoanatomy of the epiglottis and preepiglottic space of the lemur larynx (a non-human primate without vocal tract).

METHODS

Two normal adult ring-tailed lemur larynges obtained from natural death were investigated. The whole organ serial section technique was employed.

RESULTS

The histologic structures of the lemur epiglottis and preepiglottic space differed considerably from that of human adults. The lemur epiglottis was proportionally thick and vertical. It was connected to the thyroid cartilage anteroinferiorly without an intervening thyroepiglottic ligament and to the hyoid bone anteriorly with intervening large bundles of collagen fibers, indicating that the lemur epiglottis does not play the role of retroflection. The lemur larynges did not have a preepiglottic space. These findings also reflect the fact that lemurs do not have a descended larynx and do not acquire the pharyngeal space of the vocal tract. The lemur epiglottis was composed of fibrocartilage, adipose tissue and a small amount of elastic cartilage covered with mucosa (lamina propria and pseudostratified ciliated columnar epithelium). The histologic findings also indicate that the lemur epiglottis is not flexible and does not play the role of retroflection.

CONCLUSIONS

The results of this study are consistent with the hypothesis that, in the process of evolution, the histologic structures of epiglottis and preepiglottic space likely change to make the larynx descend and lengthen the pharyngeal space of the vocal tract for speech production in humans. Moreover, the distribution of the human preepiglottic space likely allows the epiglottis to more effectively play the role of retroflection during swallowing in order to prevent aspiration.

Evolution of Epiglottis and Preepiglottic Space of Primate Larynx as the Vocal Tract Is Acquired

OBJECTIVES

Comparative histoanatomy regarding the evolution of epiglottis and preepiglottic space (PES) of primate larynx as the supralaryngeal vocal tract (SVT) is acquired was investigated.

METHODS

Two lemur, one galago, two macaque, two gorilla, and two chimpanzee normal larynges were investigated and compared with human larynges using the whole-organ serial section technique.

RESULTS

Nonhuman primates with the limited pharyngeal space of SVT (lemurs, galago, and macaques, phyletic distant relative of humans) did not have PES. Their epiglottis was composed of cartilage that is not very flexible. Nonhuman primates with the lengthened pharyngeal space of SVT (gorillas and chimpanzees, hominids, phyletic close relative of humans) had PES. Furthermore, the PES of chimpanzees (phyletic closest relative of humans) existed astride the epiglottis similar to the human PES. The hominid epiglottises were composed of elastic cartilage, which is flexible, and play the role of retroflection. These histoanatomical structures of the epiglottis and PES reflect the fact that those features evolved as the pharyngeal space of SVT was lengthened.

CONCLUSIONS

The results of this study are consistent with the hypothesis that, in the process of evolution, the histoanatomical structures of epiglottis and PES changed and allowed the larynx to descend and the pharyngeal space of the SVT to be lengthened. This may facilitate speech production in humans. Moreover, the distribution of the human PES allows the epiglottis to more effectively play the role of retroflection during swallowing in order to prevent aspiration, which may have been derived from primate swallowing physiology.

Growth and development of epiglottis and preepiglottic space of larynx as it acquires vocal tract

Objectives

The growth and development of the epiglottis and preepiglottic space (PES) of the human larynx as it acquires the vocal tract were investigated.

Methods

Three newborns, one infant, four children (2, 7, 8, and 12 years old), and two adult normal larynges were investigated and compared using the whole organ serial section technique.

Results

The newborn PES occupied a small area just anterior to the epiglottis. It was composed of immature adipose tissue and areolar tissue. The epiglottis lay on a somewhat horizontal axis and is partially obscured behind the hyoid bone. The hyoid bone overlapped the thyroid cartilage, partially obscuring the superior thyroid notch. The newborn epiglottic cartilage was immature elastic cartilage, and the elastic fiber component was sparse. In the first 8 years of life, as the PES grew, the PES was located not only anterior to but also posterolateral and inferolateral to the epiglottic cartilage and thyroepiglottic ligament. Meanwhile, the epiglottic cartilage matured.

Conclusions

In order to develop the vocal tract for speech production, it is reported that the human larynx descends as the child grows in the first 9 years of life. This study showed that the PES, occupying a small area just anterior to the epiglottis, grew and existed astride the epiglottis as the larynx descended and the vocal tract developed. Consequently, its distribution allows the epiglottis to more effectively play the role of retroflection during swallowing in order to prevent aspiration. The human speech faculty likely develops in conjunction with swallowing physiology.

Comparative Histoanatomy of the Epiglottis and Pre-epiglottic Space of the Chimpanzee Larynx

OBJECTIVES

Understanding of the evolution of the larynx clarifies the physiology and functional histoanatomy of the present-day human organ. Comparative histoanatomy of the epiglottis and pre-epiglottic space of the chimpanzee larynx (a hominid, phyletic closest relative of humans) was investigated.

METHODS

Two normal adult chimpanzee larynges obtained from natural deaths were investigated. The whole organ serial section technique was employed.

RESULTS

The histoanatomical structures of the chimpanzees' epiglottis and pre-epiglottic space were considerably similar to those of human adults. The chimpanzees' epiglottic cartilage was relatively thin and composed of elastic cartilage. These histologic findings of epiglottis indicate that the chimpanzee's epiglottis is flexible and plays the role of retroflection. The chimpanzees' larynges had a pre-epiglottic space composed of adipose tissue and loose connective tissue. Epiglottic cartilage was connected to the thyroid cartilage anteroinferiorly with an intervening thyroepiglottic ligament and to the hyoid bone anteriorly with an intervening hyoepiglottic ligament. These histoanatomical structures of the epiglottis and pre-epiglottic space reflect the fact that chimpanzees have a descended larynx and acquire the pharyngeal space of the vocal tract.

CONCLUSION

The results of this study are consistent with the hypothesis that, in the process of evolution, the histoanatomical structures of the epiglottis and pre-epiglottic space change and allow the larynx to descend and lengthen the pharyngeal space of the vocal tract which facilitates speech production in humans. Moreover, the distribution of the human pre-epiglottic space likely allows the epiglottis to more effectively play the role of retroflection during swallowing in order to prevent aspiration.

Impact of the Paraglottic Space on Voice Production in an MRI-Based Vocal Fold Model

OBJECTIVE

While the vocal fold is in direct contact anteriorly with the thyroid cartilage, posteriorly the vocal fold connects to the thyroid cartilage through a soft tissue layer in the paraglottic space. Currently the paraglottic space is often neglected in computational models of phonation, in which a fixed boundary condition is often imposed on the lateral surface of the vocal fold. The goal of this study was to investigate the effect of the paraglottic space on voice production in an MRI-based vocal fold model, and how this effect may be counteracted by vocal fold stiffening due to laryngeal muscle activation.

METHODS

Parametric simulation study using an MRI-based computational vocal fold model.

RESULTS

The results showed that the presence of the paraglottic space increased the mean and amplitude of the glottal area waveform, decreased the phonation frequency and closed quotient. For the particular vocal fold geometry used in this study, the presence of the paraglottic space also reduced the occurrence of irregular vocal fold vibration. These effects of the paraglottic space became smaller with increasing paraglottic space stiffness and to a lesser degree with vocal fold stiffening.

CONCLUSIONS

The results suggest that the paraglottic space may be neglected in qualitative evaluations of normal phonation, but needs to be included in simulations of pathological phonation or vocal fold posturing.

The inside-out surgical anatomy of the paraglottic space a video-guided endoscopic dissection

Objectives

The paraglottic space is an essential anatomic compartment of the larynx. It is central to the spread of laryngeal cancer and to the choice of conservative laryngeal surgery and many phonosurgical procedures. Since its description, 60 years ago, the surgical anatomy of the paraglottic space was sparsely revisited. Amid the era of endoscopic and transoral microscopic functional surgery of the larynx, we provide here a long-awaited description of the inside-out anatomy of the paraglottic space.

Methodology

Using an endoscope equipped with a 3D camera, we dissected 10 hemilarynges from 5 fresh frozen cadavers from the inside out. Before dissection, we labeled the vessels through injecting them with colored latex. We explored the paraglottic space emphasizing its shape, boundaries, and contents. We documented our findings through endoscopic photography and video recordings.

Results

The paraglottic space is a spacious tetrahedral space located parallel not only to the glottic, but also to the subglottic and the supraglottic compartments of the laryngeal lumen. It has musculo-cartilaginous, musculo-fibrous, and mucosal boundaries. It is separated from the pyriform sinus only by mucosa. A cushion of fat surrounds its vascular and to a lesser extent its neural contents. Harbored intrinsic laryngeal muscles are endoscopically identifiable within the space, namely the thyroarytenoid, the lateral, and posterior cricoarytenoid muscles.

Conclusion

The endoscopic description of the paraglottic space partly fills the knowledge gap on the laryngeal anatomy from the inside out. It opens the door for novel diagnostic methods and for ultraconservative functional laryngeal interventions under endoscopic control.

Level of Evidence

N/A.

Laryngeal spaces in the newborn larynx

OBJECTIVES

Distributions of laryngeal spaces are important in understanding their functional significance. However, laryngeal spaces in the newborn larynx are enigmatic.

METHODS

Five normal human newborn larynges were investigated using whole organ serial section technique.

RESULTS

The chief newborn laryngeal spaces were the preepiglottic space, the paraglottic space and the cricoid area. They consisted of an areolar tissue area composed of brown adipose tissue (immature adipose tissue) and loose elastic and collagen fibers. The newborn preepiglottic space was immature and occupied a small area anterior to the epiglottis. The epiglottis lied on a somewhat horizontal axis and was partially obscured behind the hyoid bone. The hyoid bone overlapped the thyroid cartilage, partially obscuring the superior thyroid notch. The thyroid cartilage was present close to the hyoid bone and the thyrohyoid membrane ran between the superior surface of the thyroid lamina, and not the anteroinferior, but the posteroinferior surface of the hyoid bone. The preepiglottic space was located anterior, lateral and posterolateral to the thyroepiglottic ligament. However, the preepiglottic space was located anterior to the epiglottic cartilage. As seen in adults, the paraglottic space existed medial to the lamina of each bilateral thyroid cartilage. Each bilateral cricoid area was located along not only the superomedial but also the medial portion of the cricoid arch on both sides.

CONCLUSIONS

As the child grows, the preepiglottic space, occupying a small area anterior to the epiglottis, likely grows as the larynx descends and acquires the human adult vocal tract. From the functional histoanatomical point of view, the newborn laryngeal spaces appear to be favored for respiration and maintenance of a protective sphincter for the lower airway over phonation.

Endoscopic Treatment of cT2 Glottic Carcinoma: Prognostic Impact of Different pT Subcategories

Objectives:

The cT2 glottic squamous cell carcinomas are a heterogeneous group of lesions in terms of superficial and deep extension. As a consequence, they differ greatly in treatment indications and prognosis. The aim of the present study was to divide cT2 glottic tumors into subcategories according to radiologic and postoperative histopathologic information, in order to identify risk factors connected with determinate survival, local-regional control, and laryngeal preservation rates.

Methods:

We retrospectively analyzed 55 cT2 glottic lesions treated at a single institution by carbon dioxide laser with at least 2 years of follow-up. Clinical, radiologic, surgical, and histopathologic data were reviewed, and the tumors were accordingly divided into 5 subcategories: I, or pT2 with lateral supraglottic extension (19 patients); II, or pT2 with lateral subglottic extension (6 patients); III, or pT2 with supracommissural and/or subcommissural extension (10 patients); IV, or pT2 with deep vocal muscle infiltration (14 patients); and V, or pT3, for superior and/or inferior paraglottic space invasion lateral to the thyroarytenoid muscle not detected before operation by computed tomographic scan (6 patients).

Results:

The disease-free survival, ultimate local control with laser alone, and laryngeal preservation rates were compared for each subcategory. Statistically significant differences were found only for the pT3 subgroup (2-year rates of 16.7%, 16.7%, and 16.7% for pT3 versus 5-year rates of 80.5%, 84.7%, and 93.3% for the entire pT2 group).

Conclusions:

Endoscopic treatment of cT2 glottic tumors can be considered effective when the pT2 stage has been confirmed. In cT2/pT3 patients, after the first endoscopic resection that allows the correct pT staging, additional treatment should always be considered.

Relationship between preepiglottic space invasion and lymphatic metastasis in supracricoid partial laryngectomy with cricohyoidopexy

Objectives

The aim of this study was to determine the role of preepiglottic space (PES) invasion in lymph node metastasis and prognosis in patients undergoing supracricoid partial laryngectomy (SCPL) with cricohyoidopexy (CHP).

Methods

A retrospective review of 42 previously untreated patients with squamous cell carcinoma of the larynx that underwent surgery was performed. The mean age of the subjects was 61.3 years, and the male-to-female ratio was 38:4. Regarding their pathological stages, there were 3, 8, 22, and 9 cases of stage T1 to T4, respectively. Concerning the disease stage of the cervical lymph nodes, there were 30, 5, 6, and 1 cases with N0 to N3, respectively.

Results

The PES invasion rate was 23.8% (10/42). Significant correlations were found between PES invasion and cervical lymph node metastasis (P=0.002). Seven of the 10 patients (70.0%) with PES invasion had cervical lymph node metastasis, whereas only 5 of the 32 patients (15.6%) without any evidence of PES invasion had lymph node metastasis. There was also a significant correlation of PES invasion with age (P=0.002) and T stage (P=0.030). However, there was no significant relationship between gender, primary tumor site, anterior commissure invasion, subglottic extension, paraglottic space invasion and PES invasion. There was a 5-year disease-specific survival of 70%. PES invasion served as a statistically significant prognostic factor for disease-specific survival (P=0.004). Cervical nodal metastasis (P=0.003) and subglottic extension (P=0.01) were also statistically significant prognostic factors associated with disease-specific survival.

Conclusion

The PES invasion was significantly related to the cervical lymph node metastasis and prognosis in patients undergoing SCPL with CHP.

Histopathological study of correlation between laryngeal space invasion and lymph node metastasis in glottic carcinoma

Objectives:

The paraglottic space and cricoid area of the larynx are made up of loose, areolar tissue composed of loose elastic and collagenous fibres and adipose tissue. They contain the main blood vessels of the larynx. We examined the correlation between the histopathological extension of glottic carcinoma into the paraglottic space or cricoid area and the development of cervical lymph node metastasis.

Study design:

We reviewed the medical charts of 45 patients (44 men and one woman) who had undergone total laryngectomy for squamous cell carcinoma of the glottis between 1991 and 2003.

Methods:

Macroscopic and microscopic study of the removed larynges of the same patients was performed, and the histopathological evidence for invasion of the paraglottic space or cricoid area was analysed.

Results:

Eight of the 24 patients (33 per cent) with invasion of the paraglottic space or cricoid area had cervical lymph node metastasis. In contrast, only one of the 21 patients (5 per cent) without any evidence of invasion of either space had lymph node metastasis. This difference was statistically significant (p < 0.05). In the 36 patients free of cervical lymph node metastasis, recurrence in the neck occurred in six (38 per cent) of the 16 patients with paraglottic space or cricoid area invasion, but in only one (5 per cent) of the 20 patients without paraglottic space or cricoid area invasion (p < 0.05).

Conclusion:

In patients with glottic carcinoma, invasion of cancer into the paraglottic space or cricoid area is an important prognostic factor for the development of cervical lymph node metastasis.

The importance of pre-epiglottis space invasion in the treatment planning of larynx and hypopharynx cancer

The involvement of pre-epiglottis space can change the indication for partial laryngeal resection.

Aim

The aim of this study was to evaluate inter-observer and intra-observer agreement by means of computed tomography analysis regarding the involvement of the pre-epiglottis space (PES) from carcinoma of the upper aerodigestive tract and its relation with therapeutic planning.

Materials and Methods

Retrospective study of ninety-five computed tomography exams of patients with squamous cell carcinoma, from 1990 to 2004, were selected and evaluated; 87 were males and eight females, with ages ranging from 32 to 73 years. Imaging results were analyzed twice by three radiologists, individually, without any previous knowledge of the clinical stage. No patient had received any previous treatment up to the moment of imaging examination, such as surgery, chemotherapy or radiotherapy. All the cases were confirmed by biopsy. Information was obtained from the medical charts.

Results

Kappa Index was calculated by assessing agreement between the three observers. We obtained substantial to almost perfect levels of agreement.

Conclusions

After a general Kappa Index of 0.72, the results suggest a substantial agreement in the involvement of the PES by means of computed tomography analysis.

Has the degree of contrast enhancement with MR imaging in laryngeal carcinoma added value to anatomic parameters regarding prediction of response to radiation therapy?

BACKGROUND AND PURPOSE

Our aim was to retrospectively investigate the prognostic significance of the degree of contrast enhancement in tumors and its additional value in previously considered MR imaging parameters with regard to local control of laryngeal cancer treated with radiation therapy (RT) alone.

MATERIALS AND METHODS

Pretreatment MR images of 64 consecutive patients (54 men and 10 women, 43-80 years of age) with supraglottic and glottic cancer were retrospectively reviewed on clinical and previously considered MR imaging parameters such as tumor involvement of specific laryngeal anatomic subsites, including laryngeal cartilages, tumor volume, extralaryngeal tumor spread, and, in addition, the degree of contrast enhancement. Clinical and MR imaging parameters were associated with regard to local control at 2 years by using the Cox regression model. "Local control" was defined as absence of primary tumor recurrence.

RESULTS

When using a threshold of the mean average contrast enhancement of 77%, the 2-year local control rate in the groups of patients with a degree of enhancement below and above this threshold was 57% and 70%, respectively (P=.3). Enhancement of tumor tissue in pre-epiglottic space (PES) was low, most probably due to its adipose tissue and poor vascular content, whereas tumor tissue involving paraglottic space (PGS) did enhance. Results of multivariate analysis indicated that the degree of contrast enhancement yielded the prognostic information (P=.07) with 2 independent prognostic factors: primary tumor volume (P=.007) and subglottic extension (P=.002) with regard to local control. Using these previously mentioned 3 MR imaging parameters as potential risk factors, we defined 4 categories, resulting in the following local control rates respectively: 90% for the group without risk factors, 73% for the group with 1, 60% for the group with 2, and finally 0% for the group with 3 risk factors, which was significantly lower than the rates in previous risk groups (P < .001).

CONCLUSION

PES has a lower degree of contrast enhancement than the PGS and may correlate with the worse outcome. Including a low degree of contrast enhancement as a parameter to primary tumor volume and subglottic extension may increase the predictive value of MR imaging for local outcome and may be helpful to identify a subset of patients whose tumors all recurred locally within 2 years after primary RT.

Lump sensation in the throat caused by tumors in the preepiglottic space

Lump sensation in the throat is a common symptom, which accounts for 4% of first patient visits to Otorhinolaryngologic clinics. The etiology includes abnormalities of the thyroid gland, cysts, tumors and chronic infections of the pharynx, larynx, esophagus and tongue base, gastroesophageal reflux and anxiety disorders. In this article we describe two rare cases of lump sensation caused by masses in the preepiglottic space and we stress the importance of thorough investigation to exclude any possible non functional causes.

Avaliação dos resultados da cirurgia conservadora do câncer da laringe

OBJETIVO: Avaliar retrospectivamente os resultados de pacientes submetidos a laringectomias parciais por carcinoma epidermóide de laringe no serviço do HMCP. MÉTODOS: Dos doentes estudados, 28 eram do sexo masculino (93,5%) e dois do feminino (6,5%) com idade variável de 42 a 66 anos, com média de 58 anos. Em relação ao procedimento cirúrgico, este foi variável, dependendo do local da extensão tumoral e do estádio. A técnica mais utilizada foi a laringectomia frontolateral em 12 pacientes (40%), seguido pela laringectomia vertical em oito (26,6%), laringectomia supraglótica em quatro (13,3%), laringectomia supracricóidea em quatro (13,3%), laringectomia near-total em um (3,3%) e cordectomia em um (3,3%). RESULTADOS: Na avaliação pós-operatória precoce, três pacientes (10%) apresentaram complicações evidenciadas por fístula faringocutâneas em dois, com boa evolução após tratamento conservador, e pneumotórax no paciente restante com boa evolução após drenagem do tórax. No que se refere à avaliação da deglutição, cinco pacientes (16,6%) apresentaram dificuldade de ingestão oral devido a aspirações recorrentes com tempo variável de 45 a 180 dias (média - 65 dias), o que obrigou a um paciente ser submetido à totalização da laringectomia devido a pneumonias recorrentes. Na avaliação tardia, de seis a 125 meses e média de 29 meses, quatro pacientes (13,3%) apresentaram recidiva locorregional, sendo dois submetidos à laringectomia vertical, um à frontolateral e o restante à supracricóidea. Em todos foram realizadas totalização e/ou radioterapia, e dois evoluíram a óbito pela doença. Vinte e quatro pacientes (84%) apresentaram preservação da voz. CONCLUSÃO: Assim, os autores concluem que a cirurgia conservadora da laringe proporciona bom controle da doença e com sobrevida aceitável, já que 90% dos pacientes estudados estão vivos e sem doença até o final da avaliação. Além disso, apresentam melhor qualidade de vida já que a maioria dos pacientes demonstrou voz e ingestão oral bem satisfatórias.

Transoral carbon dioxide laser resection of supraglottic carcinoma

Between 1981 and 1994, 34 patients with squamous cell carcinoma of the supraglottis were treated by transoral carbon dioxide laser resection, 12 of them palliatively. Additional treatment included neck dissection in 21 patients and radiotherapy in 24 patients. The 3-year overall survival was 62%, and the actuarial survival 80%. The overall survival for T1 and T2 tumors was 71%, and that for T3 and T4 tumors was 47%. The overall 3-year survival for the early stages, I and II, was 88%, and that for the advanced stages, III and IV, was 50%. These results are comparable to the outcome after conventional open partial resection. Given the significantly lower morbidity (only 7 patients required tracheostomy), we do not observe an age limit anymore. The transoral method can be recommended as curative treatment in T1 and T2 tumors and in selected T3 and T4 tumors in concert with neck dissection and/or radiotherapy. In patients with advanced inoperable tumors, laser surgery is an excellent alternative to tracheostomy and palliative radiotherapy. Prerequisites for successful application of the transoral carbon dioxide laser resection are adequate resection techniques.

Volume estimation of the preepiglottic and paraglottic space using spiral computed tomography

The purpose of this study was to estimate the volume variability of the preepiglottic and paraglottic space in the normal larynx. In 23 adult patients (12 women, 11 men), a spiral CT acquisition through the larynx was obtained. No laryngeal pathology was observed. The area of the this submucosal fat space was estimated on each slice by semi-automatic segmentation; the volume was calculated by the summation-of-areas technique. The obtained volumes were correlated with body area, body mass index and gender. The mean estimated volume of the preepiglottic and paraglottic space was 2.8 ml (SD 1.7 ml, range 0.7-5.9). No correlation with body mass index (p = 0.6), but a significant correlation with body area (p < 0.001) was found. A significant volume difference was present between men (mean 4.5 ml, SD 1.0 ml, range 2.8-5.9) and women (mean 1.4 ml, SD 0.5 ml, range 0.7-2.4)(p < 0.0001). Multiple regression analysis showed gender (p < 0.0001) to be a more important variable than body area (p = 0.17) in predicting the volume of the preepiglottic and paraglottic space. In conclusion, the volume of the preepiglottic and paraglottic space appears to be very variable, and should only be analysed with consideration of the gender of the examined subjects.

Borders and topographic relationships of the paraglottic space

The precise topographic relationships of the paraglottic space (PGS) were investigated in serial plastinated or frozen whole-organ sections of 46 normal adult larynges. Laterally, the PGS was bordered by the thyroid cartilage. Superomedially, the PGS in some specimens was only separated from the periepiglottic space by a coherent collagenous fiber septum. The paraglottic adipose tissue extended between the caudal fibers of the thyroarytenoid muscle. Inferomedially, the PGS was bordered by the conus elasticus. The anteroinferior portion of the PGS extended beyond the larynx beneath the inferior rim of the thyroid cartilage. Posteroinferiorly, the paraglottic adipose tissue extended towards the cricoarytenoid joint. Dorsally, the PGS was bordered by the mucosal lining of the piriform sinus. Due to the intimate topographic and histologic relationships present, cancer involving the PGS may rapidly infiltrate all adjacent anatomic structures.

The significance of pre-epiglottic space invasion in supraglottic laryngeal carcinomas

It is widely accepted that tumoral invasion of the pre-epiglottic space (PES) has a significant prognostic importance in supraglottic laryngeal carcinomas. The lymphatics of the supraglottic larynx drain to cervical lymph nodes via the PES. Since the supraglottic larynx is an embryological unit that contains the PES, malignant lesions of this region must be resected with en bloc surgery, including the PES. Tumors with PES invasion are already considered to be T3 in TNM staging. The purpose of this study was to review the clinical experience we have had with these tumors at Ankara University. The study comprised 150 patients with squamous cell carcinomas of the supraglottic larynx treated with either partial or total laryngectomies. Findings suggested that PES invasion occurred at early stages of supraglottic tumor progression. Suprahyoid epiglottic lesions behaved less aggressively than tumors originating from other supraglottic subsites and did not invade the PES until advanced stages. PES invasion was not considered to be a significant prognostic factor because the majority of the supraglottic lesions studied demonstrated PES invasion regardless of cervical lymph node metastases. Analysis of oncological and functional results revealed that en bloc resection of the supraglottis with the PES was facilitated by preservation of the hyoid bone.

The paraglottic space and transglottic cancer: anatomical considerations

Transglottic cancer of the larynx crosses the laryngeal ventricle and involves both the vestibular and vocal folds. It has been described to spread within the paraglottic space (PGS). This region of adipose tissue, containing blood vessels and nerves, immediately adjacent to the thyroid laminae, was originally defined by Tucker and Smith (1962). However, the precise topographic relationships of this clinically important space are still controversely discussed. Therefore, a reinvestigation was done in serial sections of 19 plastinated adult human larynges. Laterally, the PGS is bordered by the thyroid cartilage. Superomedially, the PGS is continuous with the preepiglottic space (PES) in most specimens. In some cases, the PGS and the PES are completely separated from each other by a conspicuous collagenous fiber septum. Small projections of the paraglottic adipose tissue extend between the fibers of the thyroarytenoid muscle. Inferomedially, the PGS is bordered by the conus elasticus. Anteroinferior extensions of the PGS escape the larynx beneath the inferior rim of the thyroid cartilage. Posteroinferiorly, the paraglottic adipose tissue extends between the intrinsic laryngeal muscles and towards the cricoarytenoid joint. Dorsally, the PGS is bordered by the mucosal lining of the piriform sinus. A precise knowledge of the topography of the PGS can explain typical symptoms and routes of spread of tumorous growth: extension toward the hypopharynx, extension into the anterior extralaryngeal tissues, invasion of the thyroid cartilage, impairment of vocal cord movements due to infiltration of laryngeal muscles or immobilization of the cricoarytenoid joint.

Tongue-base-cancer resection with partial supraglottic laryngectomy

INTRODUCTION

Cancer in the tongue base, which is adjacent to or invading the lingual epiglottis, requires resection of part or all of the larynx to assure adequate surgical margin. Based on whole mount laryngeal sections, a tongue base-partial supraglottic laryngectomy procedure was designed for tumors adjacent to or minimally invading the lingual epiglottis.

METHODS

A group of five patients with carcinoma of the tongue base adjacent to or minimally invading the lingual epiglottis was identified. This technique requires excision of the epiglottis, hyoepiglottic ligament, and pre-epiglottic space with the lesion. The structural physiological integrity of the false vocal cords with or without the hyoid bone is preserved.

RESULTS

Clear tumor margins were obtained in all five patients. In three patients who required up to 50% resection of the tongue base, decannulation and resumption of a full oral diet was achieved. Two patients with more extensive lesions required 70% resection of the tongue base. Both patients underwent completion laryngectomy months later because of persistent aspiration.

CONCLUSION

This preliminary report suggests that partial supraglottic laryngectomy may be used with acceptable functional results in patients with limited tongue base lesions.