Yau Hong Goh’s research while affiliated with Singapore General Hospital and other places

Objective Maxillomandibular advancement (MMA) surgery is considered a highly successful treatment for obstructive sleep apnea (OSA). Various modifications to the technique have been described. We aim to study the long-term results in Asian patients who underwent a modified MMA procedure intended to avoid bimaxillary protrusion and which involved four-quadrant bicuspid extractions with posterior maxillary alveolar setback. Method A review of operative logs from 2000 to 2003 was conducted to identify Asian patients who underwent modified MMA during that period, for treatment of moderate and severe OSA. Sleep indices and psychometric performances were prospectively analyzed. Results Eight Asian patients were included. The mean length of follow-up was 14.4 years (range: 13.0–16.5). Mean preoperative apnea-hypopnea index (AHI) was 48.9 (range: 19.0 to 84.8). Mean post-operative AHI was 31.6 (range: 6.2 to 79.5). This reduction was statistically significant (p < 0.05). Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire (FOSQ) revealed that majority of the patients (75 %) did not have excessive daytime somnolence and all patients had high FOSQ totalled scores (mean 17.7, range 11.8 to 20), indicating good functional performance. Conclusion This series is the longest follow-up of an Asian cohort who underwent modified MMA. With a mean follow-up of 14.4 years, improvement in AHI is still observed but not at a degree as large as prior studies with shorter lengths of follow-up. The purported efficacy of MMA for Caucasian patients may not be reproducible in Asian patients and long-term sustainability of this treatment's efficacy requires rigorous evaluation.

A retrospective study of 18 patients with malignant tumors of the external auditory canal and temporal bone was undertaken to gain an Asian perspective of this rare disease. Of these patients, 15 (83%) had squamous cell carcinoma (SCC) and 61% had stage T3 tumors at presentation. The mean age was 56 years (range 38-82 years). Seven (39%) of the 18 patients had radiation-associated tumors (RATs), and all had undergone radiotherapy for treatment of nasopharyngeal carcinoma. The 1-year cumulative recurrence for the RAT group was 100%, but there was no recurrence in the non-RAT group ( P = 0.001). In malignancies of the external auditory canal and temporal bone, a different classification and staging system for patients with RATs may be warranted to better guide treatment strategies.

Patients with nasopharyngeal carcinoma may have residual cervical lymphadenopathy after definitive treatment of the primary tumour and regional cervical nodal disease. Whether such lymphadenopathy truly represents persistent disease is unclear. There are few published studies addressing this clinical problem. We retrospectively and systematically reviewed the clinical records of 12 patients with nasopharyngeal carcinoma who had presented to a tertiary academic hospital, over an 11-year period, with suspected persistent cervical nodal disease after definitive radiotherapy or concurrent chemoradiotherapy. Findings on fine needle aspiration cytology and computed tomography scanning were correlated with final histopathological results. The incidence of negative neck dissection was 41.7 per cent. The positive and negative predictive values of fine needle aspiration cytology in identifying disease were 100 and 42.9 per cent, respectively. Computed tomography scanning had a positive predictive value of 58.3 per cent in identifying disease. In patients treated definitively for nasopharyngeal carcinoma, residual cervical lymphadenopathy may not represent persistent disease. Head and neck surgeons involved in the management of these patients should bear in mind the current limitations of fine needle aspiration cytology and computed tomography in confirming the diagnosis pre-operatively. Salvage neck dissection may over-treat some of these patients.

To determine the prevalence of tonsillar actinomycetes colonization in patients with and without recurrent tonsillitis and to study the association of this condition with recurrent tonsillitis and tonsillar hypertrophy. A retrospective study of 834 patients who had undergone tonsillectomy for recurrent tonsillitis (group A) and for sleep-disordered breathing without a history of recurrent tonsillitis (group B). The prevalence of tonsillar actinomycetes colonization was higher in patients who had undergone tonsillectomy for sleep-disordered breathing (44.1 per cent) than in patients who had undergone tonsillectomy for recurrent tonsillitis (33.3 per cent). The prevalence did not differ by sex or age of patient, although the occurrence rate was higher in the adult compared with the paediatric population. There was no statistically significant difference between the mean size of the tonsils removed in the two groups, and actinomycetes colonization did not affect tonsil size. Histopathological analysis of resected tonsils did not show active tissue infection. The presence of actinomyces does not indicate active disease. We are of the opinion that, although actinomyces colonization is more prevalent in patients with sleep-disordered breathing, it does not contribute to tonsillar hypertrophy nor to recurrent tonsillitis.

Recurrent nodal disease in patients with nasopharyngeal carcinoma (NPC) after definitive radiotherapy presents a difficult clinical problem. This cohort of patients poses a diagnostic challenge to the head and neck surgeon because evaluation of the post-irradiated neck, both clinically and radiologically, is known to be difficult, and it is not uncommon for neck dissection specimen in suspected recurrent nodal disease to contain no viable tumor cells. Currently, there is no well-accepted method for the preoperative determination of the presence of malignancy in these nodal diseases. Over a 7-year period in a tertiary hospital, we systematically reviewed the clinical charts of 42 patients with NPC who were diagnosed with suspected recurrent nodal disease, after radical definitive radiotherapy. Fine-needle aspiration cytology (FNAC) was performed on clinically palpable nodes and results were correlated with final histopathologic results. Findings on CT scan were also correlated with final histopathologic specimens. The specificity and sensitivity of FNAC was 75.0% and 75.0%, respectively. The positive and negative predictive value of FNAC was 93.8% and 37.5%, respectively. CT scan had a positive predictive value of 78.6%. The negative predictive value for multilevel involvement on CT scan was 20%. Radiological imaging and FNAC are useful diagnostic modalities in assessing recurrent nodal disease in the post-irradiated neck in patients with NPC. Although routine CT scan criteria for pathologic lymphadenopathy cannot be accurately applied in the post-irradiated neck, it is a useful surveillance tool in the routine follow-up of patients with post-irradiated neck with NPC. Clinicians, however, must understand their limitations when assessing these patients. The possibility of negative neck dissection must be conveyed to the patients.

Kimura's disease (KD) is a rare, benign, chronic inflammatory disease with unknown aetiology. Its manifestation is protean. KD has a predilection for the head and neck area, and typically presents as tumour-like lesions that could be easily misdiagnosed. We review our experience with four recent cases. Over a four-year period, all patients admitted to Singapore General Hospital with KD of the head and neck region were retrospectively reviewed. Biodata, presenting symptoms and clinical parameters, especially serum eosinophil levels, preoperative investigations, type of surgical procedures and outcome were documented. Four patients presented with KD of the head and neck and displayed varied manifestations of the disease. All the patients had raised serum eosinophil levels. None of them had renal involvement. Preoperative computed tomography were performed in two of the patients and showed features suggestive of KD. Fine-needle aspiration cytology that was performed in two patients was not useful in the diagnosis. All the patients underwent surgical excision of the lesions. Only one patient had multiple recurrence, both at the original and remote sites in the head and neck. The clinical presentation and behaviour of KD is very variable. Preoperative imaging is useful in the diagnosis of the disease but the final diagnosis is histological. Surgical excision is the current treatment of choice but recurrence is common. A high index of suspicion and awareness is vital in the early diagnosis and management of KD.

The aim of the study is to describe the histologic spectrum in the pseudocyst of the auricle and to identify any consistent histologic features of this condition. A prospective study was performed in which the tissue specimen from patients with pseudocyst of the auricle treated at the Department of Otolaryngology, Singapore General Hospital during a 1-year period was sent for histology. Consecutive patients with pseudocyst of the auricle who were treated had their tissue specimen sent for histology. These specimens were independently reviewed by one consultant pathologist. All 16 specimens revealed an intracartilaginous cyst devoid of epithelial lining. Interestingly, there were consistent perivascular mononuclear infiltrates of lymphocytes evident in the connective tissue layer just superficial to the anterior segment of the cartilage. Pseudocyst of the auricle is a benign condition predominantly affecting young Asian males. Histology characteristically reveals an intracartilaginous cyst devoid of epithelial lining, and there are no pathognomonic features. We postulate that an inflammatory response is crucial to the development of this condition on the basis of a consistent perivascular inflammatory response seen in all our specimens.

Ingestion of a foreign body is a common occurrence in our population. We present 2 cases that illustrate an unusual outcome of an otherwise usual occurrence. Two patients who presented with a history of ingestion of fish bones were worked up. The radiological findings were suspicious of a foreign body and both underwent examination under general anaesthesia. The endoscopic findings were normal. After further evaluation for persistent calcifications with computed tomography, a thyroid malignancy was found in the first patient and tongue cancer in the second patient. The first patient underwent elective hemithyroidectomy and the second underwent wide excision of the tumour with neck dissection. Both recovered uneventfully with regular follow-up in the outpatient clinic. There should be a high index of suspicion in patients with persistent calcifications.