by Dr. Shobha Ravichandran & Dr. Sujatha Vittal, Sankara Nethralaya, Chennai
Abstract :
Laryngeal web is a rare entity. When congenital in origin, this may be associated with various syndromes like CHARGE, Di-George syndrome, CATCH 22 syndrome and Velo Cardio Facial syndrome.
Laryngeal webs are classified based on the degree of airway obstruction1.
Type I – <35% of airway obstruction
Type II – 35-50% of airway obstruction
Type III – 50-75% of airway obstruction
Type IV- 75- 90% of airway obstruction
IMG_256
Clinical presentation of patients with laryngeal web can be varied. Patient’s may remain asymptomatic and present as unanticipated cases of difficult intubation2,3,4.
We describe the successful management of an unanticipated difficult intubation in a paediatric patient with a surprise laryngeal web for vitreo retinal surgery.
Key Words: Anaesthesia, Laryngeal Web type III, Mental retardation, Congenital Rubella Syndrome, Retinal surgery.
Case Report :
A four year old child weighing 10 kg, born full term to non-consanguinous parents, mentally challenged came to our institution with coloboma and retinal detachment for vitreo retinal surgery.
During pre-anaesthetic assessment, the child was found to have delayed milestones, facial dysmorphism and was a wheezer on regular nebulization. There was no history of snoring.
In the past, the child had undergone a surgery for undescended testis at six months of age and repair of cardiac defects ( repair of cor triatrium, PDA ligation and closure of secondum ASD, excision of fibrovascular membrane and closure with pericardial patch ) at one year of life.
Systemic Examination revealed a short systolic murmur at cardiac apex. Auscultation of respiratory system revealed a few scattered rhonchi and neurologically patient was incoherent and spastic(on regular physiotherapy). Patient was on regular anti-seizure medications following two episodes of seizures at two years of age.
Haematological values were unremarkable. Karyotypying done showed a normal male karyotype.
Echo cardiogram read as :
- CHARGE association, moderate pulmonary hypertension, right pulmonary vein obstruction.
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Repair of unrestictive cor triatrium and closure of small secondum ASD.
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Normal systemic and pulmonary venous return
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No mitral regurgitation. Mild TR with gradient 21mmHG.Trivial PR.
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Tricommissural aortic valve
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Good biventricular function
MRI brain : Thinned out corpus callosum with small pitutary gland. Pitutary volume 0.07cc. Normal cerebral hemispheres.
Airway was graded as Mallampatti I-II.
The child was scheduled for surgery after obtaining an informed high risk consent, neurology clearence and cardiology clearence who had labelled the patient as Congenital Rubella syndrome.
Following universal fasting guidelines, the patient was premedicated with 0.004mg/kg Glycopyrolate I.M. one hour before surgery. He was given his regular morning dose of anti-epileptics and broncho-dilator nebulization an hour before surgery.
Anaesthesia was induced with O2:N2O(50:50) and Sevoflurane. An I.V. access was obtained using 22G cannula and 0.45% Dextrose Saline was started. Monitoring included ECG, NIBP, SaO2, EtCO2 and Temparature. After ensuring adequate depth of anaesthesia, a trial laryngoscopy and intubation(if feasible)was planned before paralysing the patient in view of facial dysmorphism. The visualisation of vocal cords were good on direct laryngoscopy hence intubation was attempted using 4mm ID uncuffed endotracheal tube. The tube could not be negotiated through the cords and patient started desaturating. Hence bag and mask ventilation was initiated and the procedure was repeated again with 3.5mm ID uncuffed endotacheal tube without success. Next a 3mm ID uncuffed endotacheal tube was tried. Even this could not be negotiated through the cords. As repeated attempts for intubation failed, the child was brought out with bag, mask ventilation with 100% oxygen. The procedure was deffered on the given day. Child was monitored in PACU for two hours and parents were explained about the reason of cancelletion.
The Child was rescheduled for surgery 4 days later. Meanwhile an ENT opinion was sought which read as:
- Examined the larynx with 40 mm scope-
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Anterior laryngeal web classified as Type III
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Associated sub glottic stenosis grade II – III
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Minimal Tracheo malacia
Having the ENT opinion, we were better prepared next time. The thought of ProSeal LMA did cross our mind. But as the airway is difficult to access for the duration of surgery because of surgical drapes covering the face in ophthalmic surgeries we went ahead with endotracheal intubation.
After inhalational induction, larygoscopy was performed and a 2.5 mm ID endotracheal tube was passed through the cords. It was snugly fitting in the cords. After checking the correct placement of the tube by auscultation and capnography the child was paralyzed using 0.1mg/kg Vecuronium. Inj. Fentanyl 1mcg/Kg and Inj.Hydrocortisone 5mg/kg were given I.V. Analgesia was also supplemented by peribulbar block with 0.5% bupivacaine. Surgery lasted for a duration of three hours. Intra operatively vitals remained stable.Residual neuro-muscular paralyis was reversed using neostigmine and glycopyrolate. Child was extubated awake and monitored in PACU for two hours.
DISCUSSION:
The incidence of laryngeal webs has been described in children to be 1 in 10,000 births. Congenital webs usually symptomatic in infancy or early childhood, are the result of incomplete recanalisation of the primitive laryngeal airway5. The majority of glottic webs lie anteriorly between the cords; only 1-2 % are located posteriorly6. The disease is suggested by clinical symptoms such as stridor, weak crying and feeding problems, but endoscopic vision is essential for a definite diagnosis7 .
Incomplete recanalisation of the laryngotracheal tube during the third month of gestation leads to different degrees of laryngeal web formation8. The extreme of this situation is complete laryngeal atresia9 . These webs constitute a spectrum of developmental laryngeal disorders and range from a small incomplete anterior glottic web causing minimal dysphonia with extreme obstruction to a complete glottic web causing total laryngeal atresia10.
The most common site of development of laryngeal web is at the level of vocal cords anteriorly11.Patients manifest symptoms ranging from mild dysphonia to significant airway obstruction depending on the size of the web. Stridor is rare except in patients who have a posterior interarytenoid web. Acquired webs can include infectious, post traumatic and post intubation etiologies.
Laryngeal webs constitute 5% of all congenital anamolies of the larnyx. 75% of these are at glottic level. The rest are at supra glottic or sub glottic level12 . A third of these children have associated anomalies of respiratory tract- most commonly sub glottic stenosis9. Other anomalies must be suspected when respiratory distress is disproportionate to that caused by web9. Many of these patients have other congenital abnormal lesions affecting genital or renal organs, cleft lip and palate, ophthalmic conditions like coloboma of iris and squint, accessary limbs and dislocation of the hip. Chromosomal and cardiovascular anamolies are also common. A chromosome 22q11 deletion is particularly common13.
To conclude, an unexpected difficult airway can pose a real challenge to an anaesthesiologist especially in the paediatric age group.Weighing the pros and cons of a given case,the benefit of doubt should go to the patient.We decided to proceed with this case, as the child had very poor visual prognosis in the other eye and this was the salvageble eye. But it was worth the effort!!
REFERENCES :
1.Cummings CW. London: CV Mosby; 1986. Otolaryngology- Head and Neck Surgery.
2.Chong Z.K, Jawan B, Poon Y.Y, Lee J.H. Unsuspected difficult intubation caused by a laryngeal web. Br J anaesth. 1997; 79: 396-397.
3.Hodge G.E. Congenital web of the larynx. Can Med Assoc J. 1936 : 535-536.
4.Nguyen K,et al. Unexpected tracheal web encountered during difficult intubation in the operating room. Bayl Univ Med Cent. 2000; 19: 224-225.
5.Moore KL: The developing human. 3rd ed. London : WB Saunders 1982.
6.Holinger PH, Brown WT: Congenital webs, cysts, laryngoceles and other abnormalities of larynx. Annals of otology, Rhinology and Laryngology; 1967,76: 744-52.
7.Cummings CW: Otolaryngology Head and Neck surgery; London: CV Mosby; 1986.
8.Manoukian JJ, Tan AK. Embryology of the larynx. In: Tewfik TL, Der kaloustian VM eds. Congenital anamolies of Ear, Nose and Throat. New York NY: Oxford University Press; 1997: 377-382.
9.emedicine. Laryngeal stenosis. Debbie A,Eaton MD, Allan D Murray.
10.Willging JP, Cotton RT. Congenital anamolies of the larynx. In: Tewf TL, Der Kaloustian VM eds. Congenital Anamolies of the Ear, Nose and Throat.New York NY: Oxford University Press: 1997: 383-392.
11.emedicine > specialities > Otolaryngology and Facial Plastic Surgery. Laryngology Glottic stenosis. Gauri Manekar, Debbie A, Eaton, Allan D Murray.
12.International Journal Of otorhino Laryngology 2002 Oct 21; 66(1): 23-27.
13.Pedbase.org/ laryngeal web