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Biomedical subjects

W F Lau

Publications and source records attributed to W F Lau.

At least 37 records · Page 2Linked to original sources
PubMed1988

Tumor clearance at resection margins in total laryngectomy. A clinicopathologic study.

The specimens from total laryngectomy performed in 70 patients were studied using the step-serial whole organ sectioning technique. Transverse histologic sections were taken and examined for minimum tumor clearance. The clinical status of patients for at least 4 years of observation was correlated with microscopic clearance of margins. The actual presence of tumor at the margins of resection was found in 21 (30%) of the specimens. The tumor was found to reach within 1 mm, 2 mm, and more than 2 mm from the margins in nine (13%), four (6%), and 36 (51%) specimens, respectively. The anterolateral margin was most commonly involved (19%), followed by the posterolateral (11%), postcricoid (7%), and upper (1.4%) margins. Local recurrence was found to be related to degree of clearance as 10 of 21 (48%) patients with no clearance and one of nine (11%) with 1 mm clearance had local failure. None of the patients with 2 mm clearance or more developed local recurrence. It is concluded that step-serial whole organ sectioning is an adequate method for thoroughly examining resection margins in laryngectomy specimens.

Carcinoma, Squamous Cell↗
PubMed1988

Immediate tracheoesophageal puncture for voice restoration in laryngopharyngeal resection.

A 2-year prospective study on primary tracheoesophageal puncture was carried out to evaluate the morbidity of the procedure and its success in restoring speech. Fifty-two patients, 36 of whom suffered from carcinoma of the larynx and 16, carcinoma of the hypopharynx, were entered into the study. Thirty-three patients underwent total laryngectomy with primary pharyngeal closure, 14 patients had, in addition, pharyngectomy and pectoralis major myocutaneous flap reconstruction, and 5 patients had pharyngolaryngoesophagectomy and gastric transposition. Tracheoesophageal or tracheogastric speech was successful in 58, 86, and 80 percent, respectively. Manometric studies showed that the neopharyngeal sphincter pressure decreased in all instances, but a correlation between the neopharyngeal pressure and the success of tracheoesophageal speech was not demonstrable. The morbidity rate related to tracheoesophageal puncture was low. Therefore, we believe it to be a safe and feasible procedure that can facilitate early voice restoration.

Adult↗
PubMed1988

Emergency endotracheal intubation under fiberoptic endoscopic guidance for malignant laryngeal obstruction.

Endotracheal intubation under fiberoptic flexible scope guidance is an easy technique to master and can be performed under local anesthesia. It provides immediate and safe intubation of malignant obstructive lesions of the larynx and allows surgical resection and reconstruction to be carried out as an emergency procedure. Ten patients with malignant obstructive lesion of the larynx were intubated and managed successfully in this manner. Refinements of intubation techniques under fiberoptic endoscopic guidance were described.

Aged↗
PubMed1987

Induction of monocytic differentiation of HL-60 cells by 1,25-dihydroxyvitamin D analogs.

1,25-Dihydroxyvitamin D3, the hormonal form of vitamin D, induces differentiation of HL-60 human promyelocytes into monocyte-like cells in vitro. We assessed the relative activity of 30 analogs of 1,25-dihydroxyvitamin D3 in inducing development of monocytic markers in HL-60 cells. The three differentiation markers assayed were nonspecific acid esterase activity, nitro blue tetrazolium reducing activity, and phagocytic capacity. Of the known metabolites of vitamin D, 1,25-dihydroxyvitamin D3 is the most active; 50% of the cells exhibit the mature phenotype following a 4-day treatment with 10(-8) M 1,25-dihydroxyvitamin D3. Removal of either the C-1 or C-25-hydroxyl group reduces activity by 2 orders of magnitude, while epimerization of the 1 alpha- to 1 beta-hydroxyl group virtually abolishes activity. Elongation of the steroidal side chain of 1,25-dihydroxyvitamin D3 by addition of one carbon at C-24 or C-26 improves the potency by an order of magnitude. Truncation of the steroidal side chain leads to a 10-fold reduction in activity for each carbon removed. Elimination of the C-26 and C-27 methyl groups reduces activity 100-fold. Analogs with short aliphatic side chains as 1 alpha-hydroxyhomo- and bishomopregnacholecalciferol have surprisingly high activity, being only 20-fold less potent than the natural hormone. The activity of most analogs in the HL-60 system parallels their known relative affinities for the well characterized 1,25-dihydroxyvitamin D3 receptor in chick intestine, providing further evidence that this function of 1,25-dihydroxyvitamin D3 is receptor mediated.

Calcitriol↗
PubMed1987

Regional chemotherapy through a saphenous vein graft for the treatment of head and neck cancers.

Regional chemotherapy was given through a vein grafted between the common carotid and external carotid arteries to 20 patients who had a variety of advanced head and neck cancers. The objective response rate was 73.6%, which included 36.8% complete response. The median duration of response was more than 10 months. The toxicity was mild and well tolerated. The complication rate associated with the procedure was low. This form of regional chemotherapy has significant advantages over the conventional form that uses drugs given through the retrograde temporal artery because the catheter-related complications are eliminated, the perfusion of the tumor can be maintained consistently, and, consequently, the response rate is high and the duration of response is increased.

Adult↗
PubMed1987

Avoiding stenosis in the tubed greater pectoral flap in pharyngeal repair.

Replacement of circumferential defects of the pharynx with skin-lined flaps rolled into a tube had the problem of anastomotic stricture formation. To prevent and correct stenosis at the mucocutaneous junction, an interdigitating anastomotic line produced by making vertical slits on the skin edge and the esophageal stump edge is used. It allows for maintenance of the lumen despite suture line contraction.

Aged↗
PubMed1987

Present status of pharyngogastric anastomosis following pharyngolaryngo-oesophagectomy.

Pharyngolaryngo-oesophagectomy with pharyngogastric anastomosis was described more than 25 years ago. Since then it has been employed for the treatment of cancers of the hypopharynx, cervical oesophagus and larynx. Results of recent reports showed a wide variability. Our previous report of 157 such operations gave a significant morbidity and overall hospital mortality rate of 31 per cent. In the 6-year period between 1980 and 1985, 91 patients underwent this operation. The morbidity and mortality rates gradually decreased to 30 and 5 per cent respectively. Changes in the indications for the operation resulted in a reduction in the number of procedures performed in recent years. Resection of the oesophagus for cancers of the pharyngolaryngeal region is indicated only when there is actual oesophageal involvement, and would be the prime indication of pharyngogastric anastomosis.

Esophageal Neoplasms↗
PubMed1987

Reconstruction of hypopharyngeal defects in cancer surgery: do we have a choice?

Between 1982 and 1985, 83 patients with hypopharyngeal or extensive laryngeal cancers underwent pharyngoesophagectomy (48 patients), circumferential pharyngectomy (8 patients), and partial pharyngectomy (27 patients), depending on the site and extent of tumor involvement. The resultant hypopharyngeal defects were reconstructed with gastric transposition, a tubed pectoralis major myocutaneous flap, and a pectoralis major flap patch, respectively. There were three hospital deaths in the gastric transposition group (6 percent) and none in both pectoralis major flap groups. The leakage rate was 8.3 percent in the gastric transposition group, 25 percent in the tubed pectoralis major flap group, and 3.7 percent in the pectoralis major flap patch group. Stricture was avoided with the interdigitation technique used at the tubed-flap-to-esophagus anastomosis, although the fistula rate was high. The overall complication rate was higher with gastric transposition. Although swallowing was satisfactory in all three groups, 42 percent of the patients with gastric transposition experienced regurgitation. Over a follow-up period of 16 to 50 months the local recurrence rate was 5 percent, and the actuarial survival rate was 55 percent at 24 months.

Anastomosis, Surgical↗
PubMed1987

Healing between cartilage and bone ends. An experimental study.

Whether healing or nonunion occurs at the junction between cartilage and bone was studied in an animal experimental model. The costochondral junctions of the floating ribs of rabbits were excised and the cut ends of bone and cartilage reapproximated with wire. The process of healing was then observed. Fibrocartilaginous callus formed in the first week. Beginning in the second week, this was gradually replaced by bony callus, a process which started from the medullary cavity of the bone end. The cut end of the original cartilage showed no activity. The periosteum and perichondrium became continuous at 4 weeks. The site of ossification assumed the appearance of the original costochondral junction. The gap between the original cartilage and the new cartilage disappeared when fusion occurred at 48 weeks. Osteochondral junctions at various periods after operation were subjected to disruption force until the junctions were pulled apart. The average force required to break 16 junctions was 2,738 g, and was not related to the period of healing.

Animals↗
PubMed1987

Entering the pharynx in total laryngectomy.

In performing total laryngectomy for carcinoma of the larynx, the pharynx should be entered at sites away from the tumour. When the tumour is supraglottic in location, the entry should be through the lateral pharyngeal wall; and when the tumour is located in the postcricoid area, entry above the hyoid bone is preferred.

Humans↗
PubMed1987

The role of the fibreoptic bronchoscope in otorhinolaryngological practice.

Flexible fibreoptic bronchoscope has been employed in the examination of the nasopharynx, pharynx, larynx, trachea, bronchus and intrathoracic oesophagus under local anaesthesia. It is used either for diagnostic or therapeutic purposes. A total of 1690 procedures have been performed with no complication. The indications and findings in these procedures are listed. The advantages and limitations of the use of flexible fibreoptic bronchoscope as a 'panendoscopic examination' instrument are discussed.

Adolescent↗
PubMed1986

Parapharyngeal space tumours.

Tumours in the parapharyngeal space have been difficult diagnostic and management problems. Consideration of the anatomy in three dimensions may be illustrated with computed tomography. Fifteen patients with parapharyngeal space tumours are presented, including six salivary gland tumours, four neurogenic tumours and five tumours from miscellaneous origin. The tumours were all treated by surgical excision. The preferred approach was the transcervical route. Additional procedures, including total conservative parotidectomy, were carried out depending on the pathology. Mandibulotomy was required for only one patient whose tumour had infiltrated the base of the skull and extended intracranially.

Adenoma↗
PubMed1986

Tumours of the parotid--the value of clinical assessment.

A series of 131 tumours of the parotid was reviewed retrospectively to ascertain the value of clinical features in distinguishing between malignant and benign tumours. The overall proportion of malignancy in this group of tumours was 17% (23 tumours). It was found that sex, age, size, duration of symptoms, and history of rapid enlargement were non-contributory to a diagnosis of malignancy, while the presence of facial nerve paralysis, skin infiltration or ulceration, and metastatic neck nodes were found only in patients with malignant tumours. A history of pain, hardness, and fixity, found in 30-50% of parotid cancers, were significant indicators of malignancy. As the yield of routine frozen section examination on all resected parotid tumours is low, it is recommended that if resources are limited, the examination be reserved for tumours highly suspicious of being malignant.

Biopsy↗
PubMed1986

Prospective screening for multiple tumors of the upper aerodigestive tract: a simple routine procedure.

Detection of a second primary at the time of initial work-up of patients with head and neck cancers has an important bearing on management planning. In a 12-month period, a series of 105 patients with an index head and neck primary (skin malignancies excluded) of the squamous cell type were subjected to the following screening procedure. Under topical anesthesia, with the patient in the sitting position, a small-size flexible bronchofiberscope (Olympus B3R) was introduced through the nose. As the scope was advanced, the nasal cavity, nasopharynx, oropharynx, hypopharynx, and larynx were examined. The tracheobronchial tree was also examined if the chest x-ray showed abnormal findings. The endoscope was then passed down to examine the esophagus, with oxygen insufflated via the biopsy channel at a rate of 1 liter per minute. The index primary sites included the tongue (20), alveolus (7), floor of mouth (2), palate (4), buccal mucosa (3), hypopharynx (17), and larynx (52). There was little patient discomfort and no complication. Nine patients (8.5%) were found to have simultaneous primary tumors including two patients with triple primaries and one with quadruple lesions. The additional tumors were in the following sites: esophagus (6), tonsil (2), floor of mouth (1), nasopharynx (1), bronchus (1), palate (1), and oropharynx (1). The treatment plans were changed in all nine patients with the discovery of multiple tumors. It is concluded that the panendoscopic screening in the manner described is simple, safe, and convenient and the information is contributory to treatment planning.

Adult↗
PubMed1985

Sialadenoma papilliferum.

Sialadenoma papilliferum is a rare benign papillary intraoral tumour most frequently affecting men over the age of 50. The tumour bears many similarities to adenolymphoma of the parotid and may be considered a variant of the latter. A case is presented and the literature is reviewed.

Adenoma, Pleomorphic↗
PubMed1983

Surgical management of benign oesophago-pleural fistula.

Three cases of oesophago-pleural fistula are presented. Two resulted from foreign body perforation of the oesophagus and one followed left lower lobectomy for bronchiectasis. All three presented late; the time lapse ranged from 6 days to 2 months. An initial course of conservative treatment was given to all three patients. Alimentation via nasogastric tube feeding, gastrostomy or total parenteral nutrition was carried out. The pleural fluid grew the anaerobe, Bacteriodies melaninogenicus, in all three cases. Gram-negative aerobes, Escherichia coli and Proteus mirabilis, were also cultured. Closed intercostal drainage and a course of appropriate antibiotics were instituted. The patients were subjected to surgery after the infection had been brought under control. Simple repair was performed in two patients. Exclusion of the oesophageal leak with drainage and later reconstruction was carried out in the third patient. Although all three patients recovered, the morbidity was considerable. The duration of hospital stay ranged from 2 to 4 months.

Adult↗
PubMed1981

Oesophageal microbial flora in carcinoma of the oesophagus.

In 79 patients, with carcinoma of the oesophagus, oesophageal aspirates obtained at oesophagoscopy were cultured for aerobic and anaerobic organisms in an attempt to identify the microbial flora. The aspirate culture was correlated with the pathogens isolated when infective complications developed after operation. Bacteroides were isolated from the oesophagus in 39.2% of patients, streptococcus in 10.1% and coliform organisms in 7.6%. No growth was obtained in 35.4% patients. Forty-one patients underwent oesophageal resection. Six of these had the complication of empyema thoracis in the postoperative period. Two patients had identical organisms isolated from the oesophagus and the empyema. B. melaninogenicus was cultured from the pleural fluid in two patients whose oesophageal aspirate culture yielded no growth. Six patients developed wound infection, all with anastomotic cutaneous fistula. There was no demonstrable relationship between the organisms isolated from two sources. Prophylactic antibiotic administration should be directed against the bacteroides, since it is the most common organism isolated from within the oesophagus.

Anti-Bacterial Agents↗