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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.57 no.4 Campinas July/Aug. 2007
Temporary lingual nerve dysfunction following the use of the laryngeal mask airway. Case report*
Disfunción temporal de nervio lingual trás del uso de máscara laríngea. Relato de caso
Hugo Eckener Dantas de Pereira CardosoI; Durval Campos Kraychete, TSAII; José A. Lima FilhoI; Luciano S. Garrido, TSAIII; Anita Perpétua Carvalho RochaIV
da Clinica de Anestesia de Salvador
IIProfessor Doutor, Disciplina de Anestesiologia da UFBA; Coordenador do Ambulatório de Dor da UFBA
IIICoordenador do CET em Anestesiologia do Hospital Universitário Professor Edgard Santos
IVMestre em Anestesiologia pela Faculdade de Medicina de Botucatu-UNESP; Médica do Serviço de Anestesiologia do Hospital da Sagrada Família
OBJECTIVES: The laryngeal mask has been frequently used in Anesthesiology.
Although the rate of complications with this technique is smaller than that
of the endotracheal tube, it is not devoid of risks, especially in cases of
difficult airways. The objective of this study was to report a case of unilateral
lingual nerve damage after the use of the laryngeal mask airway.
CASE REPORT: A female patient underwent a surgical procedure for removal of bilateral breast prosthesis under general, balanced anesthesia, with a size three laryngeal mask. The balloon was inflated with 30 mL of air. After the first postoperative hour, she developed decreased sensation and pain in the oropharynx and posterior two thirds of the tongue, which evolved for loss of taste in the next 24 hours. A tentative diagnosis of lingual nerve neuropraxis secondary to the use of the laryngeal mask was made. After three weeks, her symptoms subsided.
CONCLUSION: Although complications after the use of the laryngeal mask airway are rare, they do occur, and neuropraxis of the lingual nerve is one of them. The diagnosis is clinical and it has a good outcome, with resolution of the symptoms within a few weeks or months.
Key Words: COMPLICATIONS: nerve damage, lingual nerve; EQUIPMENT, Laryngeal mask.
Y OBJETIVOS: La máscara laríngea ha sido utilizada con frecuencia
en Anestesiología. El empleo de esa técnica, aunque esté
relacionada a un menor número de complicaciones cuando se le compara
a la cánula traqueal, no está exento de morbidez, principalmente
en los casos de vía aérea difícil. El objetivo de este
relato fue presentar un caso de lesión unilateral de nervio lingual trás
del uso de la máscara laríngea.
RELATO DEL CASO: Paciente del sexo femenino, sometida a intervención quirúrgica para cambio de prótesis mamaria bilateral, bajo anestesia general balanceada, con máscara laríngea de tamaño tres. El volumen aplicado para insuflación del globo fue de 30 mL de aire. Después de la primera hora del postoperatorio, se inició el cuadro de adormecimiento y dolor en la garganta y en los dos tercios posteriores de la lengua que evolucionó en 24 horas con pérdida de la percepción del sabor de los alimentos. La sospecha diagnóstica fue de neuropraxia del nervio lingual por el uso de máscara laríngea. Este cuadro se mantuvo por tres semanas, período en que se obtuvo una resolución de los síntomas.
CONCLUSIÓN: Complicaciones después del uso de máscara laríngea, a pesar de no frecuentes, pueden ocurrir. La neuropraxia del nervio lingual es una de ellas. Su diagnóstico es clínico y su evolución es favorable con resolución de los síntomas en semanas o meses.
The laryngeal mask, created by Archie J. I Brain in 1980 1, is an intermediate device between the face mask and endotracheal tube. This mask is placed in the hypopharynx, creating a seal around the glottis, and is used to maintain opened airways in certain surgical procedures. It was used in 23% of general anesthesias performed in the USA in 1998 2.
Although this technique has a lower rate of complications than the endotracheal tube, it is not devoid of morbidity, especially in cases of difficult airways 3,4. Sore throat is the most common complaint, with an incidence that varies from 10% to 40% 5. However, neuropraxis of the hypoglossal, recurrent laryngeal, and lingual nerves have been reported 7,8.
The objective of this report was to present a case of unilateral lingual nerve damage after the use of the laryngeal mask airway, and to discuss its diagnosis and evolution.
A female patient, 36 years old, weighing 60 kg, 174 cm, underwent bilateral breast prosthesis change under general, balanced anesthesia. Monitoring consisted of electrocardioscope at the DII derivation, pulse oximetry, plestimograph, non-invasive blood pressure, capnograph, and capnometry.
Anesthesia consisted of 3 mg of midazolam, 100 µg of fentanyl, 100 mg of propofol, and 30 mg of rocuronium; a number 3 laryngeal mask was then inserted. The balloon was inflated with 30 mL of air. The proper positioning of the device was confirmed by capnography.
Anesthesia was maintained with sevoflurane and oxygen under controlled mechanical ventilation. The procedure lasted two hours. The patient came out of anesthesia without any problems. She was transferred to the recovery room without any complaints. After one hour, she developed decreased sensation and pain in the throat and anterior two thirds of the tongue that evolved, during the next 24 hours, to complete loss of taste. A tentative diagnosis of neuropraxis of the lingual nerve secondary to the laryngeal mask was made. After three weeks, her symptoms subsided.
Nerve lesion is a complication that has been reported after laryngoscopy and tracheal intubation, but it is a rare occurrence after the use of the laryngeal mask. There are reports in the literature of episodes of neuropraxis associated with the use of the laryngeal mask, and the lesions described usually affect the recurrent laryngeal, hypoglossal, and lingual nerve 10. The clinical presentation depends on which nerve was damage. Lingual nerve damage is associated with loss of taste and sensation in the anterior region of the tongue; lesion of the hypoglossal nerve leads to difficulty to swallow; and the lesion of the recurrent laryngeal nerve to postoperative dysarthria, stridor, and aspiration 4. This patient presented initially with decrease sensation and pain in the throat and anterior two thirds of the tongue evolving, over the next 24 hours, to complete loss of taste, which is compatible with lingual nerve damage.
Every case of neuropraxis described so far resolved spontaneously, taking anywhere from one week to nine months 6,8,9,11,12. In this report, the period of spontaneous resolution was three weeks, which is compatible with the cases described in the literature.
The lingual nerve, a branch of the posterior branch of the mandibular nerve, located medial and anteriorly to the inferior alveolar nerve and to the lateral pterygoid muscle, is responsible for the sensitivity of the mucous membrane of the tongue. The lingual nerve has branches that cross the maxillary artery and the chorda tympani. These branches innervate the mucous membrane of the anterior two thirds of the tongue, mouth and adjacent gum, and the sublingual gland (Figure 1). The taste buds of the anterior two thirds of the tongue are innervated by the fibers that run through the chorda tympani 12. Neuropraxis of the lingual nerve can result from damage anywhere along the nerve, but it is more common between the lateral pterygoid muscle and the jaw 9.
Some factors are responsible for a higher incidence of neuropraxis of the lingual nerve. Among them are: perioperative manipulation of the laryngeal mask, fixation of the mask towards the mandible 9, use of nitrous oxide, using a device of improper size, excessive inflation of the balloon, anesthesiologist without experience, and difficulty to insert the device. Although nitrous oxide was not used in the perioperative period, it is known that this gas may increase the pressure in the balloon by 9% to 38%, leading to nerve compression 13. In this case, the pressure in the mask was not mentioned, but it should not exceed 60 cmH2O 14,15.
The laryngeal mask comes in different sizes. Numbers four and five are indicated for non-obese adults 16. In this case, a number 3 mask was used, which could explain the neuropraxis, since using a laryngeal mask smaller than recommended makes it more difficult to obtain the proper seal and, consequently, the need to inject a greater volume of air in the balloon, leading to excessive compression of adjacent structures.
To conclude, the use of the laryngeal mask is associated with a very low incidence of complications, and neuropraxis of the lingual nerve is one of them. Its diagnosis is clinical and it has a good prognosis, with resolution of the symptoms within a few weeks to months. Although neuropraxis of the lingual nerve is a benign condition, it is important to notice that it can be avoided by using the laryngeal mask properly.
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Hugo Eckener Dantas de Pereira Cardoso
Rua Pernambuco, 405/1003
Ed. Água Branca Pituba
41830-390 Salvador, BA
Submitted em 21
de junho de 2006
Accepted para publicação em 18 de abril de 2007
* Received from Clínica de Anestesia de Salvador, BA