Introduction
Congenital lymphatic malformations are rare lesions, with a reported incidence of 1 in 6000 to 1 in 16 000 live births.Reference Burezq, Williams and Sachin1 These benign lesions can be described as macrocystic, microcystic or mixed in type. The majority of cases are diagnosed at birth, with 80 per cent diagnosed by the second year of life.Reference Goetsch2 A small number are identified in adulthood. The head and neck is the commonest site: 75 per cent of lesions are found within this region.Reference Burezq, Williams and Sachin1
Congenital lymphatic malformations remain a challenging clinical problem due to the possibility of a significant local mass effect together with infiltrative margins. There is currently no accepted ‘gold standard’ for their management. Symptomatology varies dependent on the size and site of the lesion but can include significant airway obstruction and swallowing difficulties. Macrocystic disease may be managed by surgical excision or sclerotherapy, but neither is a satisfactory treatment modality for microcystic disease.
In this report, we describe the novel use of an existing technology, radiofrequency ablation (also known as Coblation; Arthrocare, Austin, Texas, USA), for the debulking of paediatric microcystic lymphatic malformations occupying the upper aerodigestive tract.
Case reports
The five cases we describe all had a combination of macro- and microcystic disease. Open surgery, with the attendant risk of neurovascular damage and loss of function, was undertaken in two children in order to remove the macrocystic portion of the disease. The microcystic disease had previously been debulked with either CO2 laser or ‘cold steel’ resection. In those cases in which radiofrequency ablation was used to debulk the tongue, the parents were warned pre-operatively that ‘sloughing’ of the tongue was likely post-operatively, and each patient was reviewed in the out-patient clinic. Radiofrequency ablation was subsequently successfully used to debulk and control intra-oral and laryngopharyngeal disease and to ameliorate symptoms. This included improving the upper airway to the extent that tracheostomy decannulation was possible, facilitating mouth closure and achieving dental occlusion.
Technique
A Coblation tonsil wand (EVac 70 Xtra Plasma Wand; Arthrocare ENT, Austin, Texas, USA) was used for disease within the oral cavity and oropharynx, whilst a laryngeal wand (PROcise LW Plasma Wand, Arthrocare ENT) was used within the laryngopharynx. In each case, a coblation setting of 7 and coagulation setting of 3 were used. Appropriately sized McKesson dental props were used to access the floor of the mouth, tongue and oropharynx, and suspension microlaryngoscopy was used to access laryngopharyngeal disease.
Care was taken to avoid damage to the papillae of the submandibular ducts in the anterior floor of the mouth.
Each child received an intravenous, broad spectrum antibiotic at induction of anaesthesia, plus a further 5-day course of post-operative oral antibiotic.
Children with disease in the oral cavity and oropharynx were treated as day cases if there were no airway concerns, whilst those with laryngeal disease were admitted overnight for observation and discharged the following day.
Case one
The first child in our series had previously undergone three operative procedures (using cold steel, bipolar diathermy and CO2 laser) to debulk microcystic disease involving the oral cavity, tongue and oropharynx (Figure 1). She then underwent two radiofrequency ablation procedures, the first comprising wedge excision of the anterior tongue (at 12 years 1 month) and the second to clear laryngopharyngeal disease (10 months later) (Figure 2). After the second treatment, she achieved complete mouth closure without tongue protrusion. The improvement in her airway facilitated tracheostomy decannulation, enabling normal dietary intake.
Clinical photograph of case one, demonstrating incomplete mouth closure due to tongue and floor of mouth microcystic disease.
Intra-operative laryngoscopic view showing radiofrequency debulking of laryngopharyngeal microcystic disease in case one.
Case two
This child had previously undergone CO2 laser vaporisation of the right arytenoid at the age of six months. Extensive laryngopharyngeal disease was successfully debulked using radiofrequency ablation when she was 3 years 11 months of age, avoiding the need for a tracheostomy (Figure 3).
Intra-operative laryngoscopic view showing radiofrequency ablation of laryngopharyngeal microcystic disease in case two.
Case three
The third child in our series presented with macroglossia at birth, with an extensive cystic hygroma extending into the neck. The infra-mylohyoid part of the lesion was excised along with the submandibular gland, at the age of three months. Twenty-one months later, the child underwent wedge resection of the anterior tongue using cutting diathermy. However, contact points between her teeth and the tongue and floor of mouth continued to bleed intermittently, and the lack of tongue mobility continued to make feeding difficult. Radiofrequency ablation was successfully used to debulk the floor of mouth disease and to provide definition to the tongue tip, on two separate occasions (Figures 4 and 5). Following the initial radiofrequency ablation, the child was successfully decannulated. At the time of writing, she continued to feed well and had a much improved voice.
Intra-operative photographs showing first use of radiofrequency ablation debulking and ‘resurfacing’ of oral cavity disease in case three.
Intra-operative photographs showing second episode of radiofrequency ablation in case three. Small areas of disease surrounding the papillae of the submandibular ducts were not ablated to avoid duct stenosis.
Case four
The fourth child in our series presented with a large cervical cystic hygroma that had been diagnosed antenatally. Surgical resection was used to manage the cervical macrocystic disease at the age of 13 months. Throughout early childhood, the microcystic component of the disease continued to proliferate, resulting in macroglossia and incomplete mouth closure. The child's protruding tongue was consistently dry and excoriated, with bleeding on contact. Radiofrequency reduction of her tongue at three years of age permitted complete mouth closure and dental occlusion, with subsequent progression from a liquid to solid diet (Figure 6).
Clinical photographs showing successful reduction of tongue volume following radiofrequency ablation, enabling complete dental occlusion, in case four.
Case five
The fifth child had mixed macro- and microcystic disease. The cervical macrocystic component was resected, leaving minimal residual disease in the submandibular triangle, at the age of 4 years 11 months. Microcystic disease involving the tongue tip was ‘resurfaced’ using radiofrequency ablation at six years of age (Figure 7), with good improvement in the previous intermittent inflammation and bleeding.
Intra-operative photographs showing radiofrequency ablation ‘resurfacing’ of microcystic disease involving the tongue tip, in case five.
Discussion
Cystic hygromas (lymphatic malformations) result from abnormal development of the lymphatic system and its connection to the venous system.Reference Goetsch2, Reference McClure and Sylvester3 Histologically, these lesions are composed of dilated lymphatic channels with one or two endothelial layers; an adventitial layer may also be present. The abnormal lymphatics can vary in size depending on their location and surrounding tissue.Reference Kennedy, Whitaker, Pellitteri and Wood4 A detailed classification system is not commonly used clinically, with most surgeons dividing such lesions into macrocystic, microcystic or mixed-type disease.
Infra-mylohyoid lymphatic malformations tend to be macrocystic and as such are amenable to surgical excision or sclerotherapy, whereas supra-mylohyoid lymphatic malformations are usually microcystic.Reference Grimmer, Mulliken, Burrows and Rahbar5 The treatment of microcystic lymphatic malformations is particularly difficult, as surgical resection is not possible due to the infiltrative nature of the disease. Surgical excision would present an unacceptable risk to neurovascular structures, with significant resultant morbidity. Therefore, emphasis is placed on debulking microcystic disease in order to facilitate swallowing and improve the upper airway. Tracheostomy insertion may be required when the floor of the mouth, tongue and/or laryngopharynx is involved.
Symptoms usually result from a mass effect, infection or haemorrhage, and can result in the onset of stridor, dysphagia and dysarthria. Incomplete excision and shifting hydrostatic pressures combine to explain the high incidence of residual and recurrent disease and the need for multiple procedures.Reference Grimmer, Mulliken, Burrows and Rahbar5 Once an area of lymphatic malformation is removed, the inflow of lymph may be shifted towards the remaining dilated lymphatic spaces. Alternatively, new lymph channels may sprout into areas that were previously unaffected, resulting in vesicle malformation on mucosal surfaces.Reference Grimmer, Mulliken, Burrows and Rahbar5
Within the oral cavity and oropharynx, several techniques have been used to debulk lymphatic malformations. These include steroid injections, electrocoagulation, CO2 laser excision and radiofrequency ablation (also known as Coblation).Reference Cable and Mair6, Reference Bloom, Perkins and Manning7 Electrocautery and laser excision are both associated with significant thermal damage to surrounding tissues, with consequent fibrosis and scarring.
Radiofrequency ablation is a low-temperature, bipolar radiofrequency modality that causes molecular disassociation and volumetric removal of target tissue by generating a field of ionised sodium molecules.Reference Ryu, Park and Jeong8
Ryu et al. have described the successful use of radiofrequency ablation to treat microcystic disease of the tongue in a 12-year-old child.Reference Ryu, Park and Jeong8 They reported a subsequent significant reduction in both mucosal bleeding and the extent of the tongue lesions, and concluded that radiofrequency ablation represented an alternative treatment modality for lymphatic malformations of the oral cavity, particularly for symptomatic relief.
• Congenital lymphatic malformations have no accepted ‘gold standard’ management
• Radiofrequency ablation is a safe, viable alternative to ‘cold steel’ or laser excision, for upper aerodigestive tract lesions
• It enables effective debulking of floor of mouth microcysts and ‘resurfacing’ of the tongue
• It reduces bleeding and avoids thermal damage to surrounding tissues
Likewise, Roy et al. have reported the amelioration of pain, bleeding and eating difficulty in three children with microcystic disease of the tongue, following radiofrequency ablation.Reference McClure and Sylvester3 Two of the children had previously demonstrated rapid recurrence of disease following wide local excision.Reference Roy, Reyes and Smith9
Radiofrequency ablation was reported to have no complications in the four children described in Ryu and colleagues' and Roy and colleagues' papers.
Radiofrequency ablation has been successfully used in procedures involving other areas of the head and neck, including tonsillectomy, reduction of inferior turbinates, uvulopalatopharyngoplasty, tongue base reduction and laryngeal papillomata.Reference Greene10–Reference Timms, Bruce and Patel13
Our five patients had each had only limited responses to traditional methods of microcystic lymphatic malformation treatment. However, they all responded well to radiofrequency ablation, with reduced symptoms and improved function.
Conclusion
Radiofrequency ablation (also known as Coblation) of congenital lymphatic malformations of the upper aerodigestive tract represents a safe, viable alternative to cold steel, laser and diathermy techniques. Radiofrequency ablation achieves effective debulking of floor of mouth microcysts and resurfacing of the tongue, and avoids the surrounding tissue damage (with associated excessive bleeding and morbidity) that may complicate other treatment modalities. Our case series includes the first description of successful treatment of airway obstruction due to paediatric laryngopharyngeal microcystic disease, using radiofrequency ablation.
