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Biomedical subjects

J Irish

Publications and source records attributed to J Irish.

28 records · Page 2Linked to original sources
PubMed1997

Biophysics of airflow within the airway: a review.

An understanding of the fundamental principles that govern flow through the airway, like anatomy and physiology, is essential for the practising otolaryngologist. Failure to grasp these principles prevents the clinician from understanding why certain things happen clinically and why certain treatments are effective. This review presents the basic concepts of fluid mechanics as applied to the airway, using commonly encountered clinical situations to further illustrate ideas. Since air is a gaseous fluid, a review of the gas laws initiates the reader. Laminar and turbulent flow is discussed as well as the method used to distinguish between the two. Also included is a brief review of the air/liquid interface inside an alveolus, as well as a discussion of airflow through an endotracheal tube.

Airway Obstruction↗
PubMed1996

Flap selection in cranial base reconstruction.

We have compared our local, pedicled, and free-flap reconstructions for 90 skull base defects performed over the past 10 years. The pericranial flap was found to provide a reliable dural seal. Free-flap reconstructions exhibited a significantly higher incidence of uncomplicated primary wound healing (95 versus 62.5 percent) and a much lower incidence of flap loss (0 percent), cerebrospinal fluid leak (5 percent), meningitis, and abscess (0 percent) when compared with defects reconstructed with pedicled myocutaneous flaps. We conclude that microvascular free-tissue transfer is the safest, most economical procedure when faced with moderate to large composite defects of the cranial base.

Female↗
PubMed1995

Outcome following radiotherapy in verrucous carcinoma of the larynx.

PURPOSE: To evaluate the outcome of patients with verrucous carcinoma of the larynx treated at the Princess Margaret Hospital with respect to control rates with radiotherapy, the salvage of local failure, the risk of regional lymph node metastasis following radiation therapy, and the risk of anaplastic transformation following radiotherapy. METHODS AND MATERIALS: Forty-eight patients underwent primary treatment for verrucous carcinoma of the larynx in the period between January 1961 and December 1990. This represented 1.1% of cases of laryngeal cancer seen in this time period. Forty-three received radiotherapy and 5 had surgery as the primary treatment. Several radiation dose-fractionation schedules were used, the most frequent being 50 Gy in 20 fractions in 4 weeks (31 cases), while eight patients were treated with 55 Gy over 5 weeks. RESULTS: The 5-year rate of local control was 59% for the 43 patients treated with radiotherapy. Surgical salvage was universally successful in all cases where it was attempted. The five cases treated with surgery alone did not experience relapse. Only one patient died of verrucous carcinoma. He had been medically unfit for surgical intervention at the time of initial treatment and at the time of relapse. He underwent a truncated course of radiotherapy (24 Gy in 3 fractions over three weeks in 1975). There was no evidence of increased neck relapse compared to other forms of laryngeal carcinoma following radiation treatment. No evidence to support anaplastic transformation of tumors treated with radiotherapy was evident in this series. CONCLUSIONS: Local control using radiation treatment is less successful than with ordinary invasive and in situ squamous carcinomas of the larynx. Nevertheless, the treatment is effective and provides an appropriate option for laryngeal conservation, especially in advanced lesions where total laryngectomy may be the only treatment alternative. Surgical salvage of radiation failures contributes to very high rates of cure for verrucous carcinoma of the larynx. Anaplastic transformation of cases treated with radiotherapy was not observed in any case in this series.

Adult↗
PubMed1994

Reinnervated lateral antebrachial cutaneous neurosome flaps in oral reconstruction: are we making sense?

Eight patients who underwent a partial glossectomy and associated floor of the mouth resection for squamous cell carcinoma were reconstructed with a sensate radial forearm flap in which the lateral antebrachial cutaneous nerve was anastomosed to the (divided) lingual nerve. The patients were compared prospectively with matched controls who received noninnervated forearm flaps for the same defect. A "blinded" therapist performed detailed sensory testing at least 6 months following surgery. In all modalities examined, the sensate proved superior to the nonsensate flap and not statistically different from the opposite side of the tongue. Two-point discrimination and pressure sensitivity were much greater in the innervated forearm flaps than in the forearms from which they came. The results are discussed with reference to the density of sensory receptors, the degree of cortical representation, and the subcortical anatomy of the neurosensory tracts. It appears that the density of sensory receptors is not directly related to the sensory potential in a given tissue transfer and that this potential is more related to the cortical fidelity of the recipient nerve. A historical matched cohort of 10 patients receiving pectoralis flaps for similar defects also was examined. Although the follow-up was longer, reinnervation was of a very low order--even worse than with noninnervated forearm flaps. This work supports the concept that sensory reinnervation should be attempted whenever possible following ablative oral surgery. This would include suture or grafting of major sensory nerves as well as the reinnervation of flaps.

Aged↗
PubMed1993

Horner's syndrome following a thyroidectomy.

A case of Horner's syndrome following a thyroidectomy for a benign multinodular goiter is presented, the literature reviewed, and possible explanations are discussed. Theories to explain this phenomenon include: local trauma to the sympathetic chain during retraction of the carotid sheath, anatomical variations which leave a patient susceptible to damage to the sympathetic chain, postoperative hematoma compressing the sympathetic chain, and ischemic damage to the sympathetic chain.

Aged↗
PubMedDate not supplied

Reconstruction of total lower lip and chin defects using the composite radial forearm--palmaris longus tendon free flap.

BACKGROUND: Functional and aesthetic restoration of total lip and chin defects can be achieved using the composite radial forearm-palmaris longus tendon free flap. OBJECTIVE: To present the technique we use and our experience with this form of reconstruction in 10 consecutive patients with total lip and chin defects who were surgically treated between 1992 and 1998. METHODS: The palmaris longus tendon acting as a sling over which the flap is draped is responsible for long-term maintenance of vertical lip height and lip support. The factors responsible for this are the long-term maintenance of vertical lip height and lip support and the transfer of facial muscle activity to the neolip. RESULTS: All patients were satisfied with their final reconstructive result. Oral competence for deglutition and speech was achieved in all patients in our case series, with no incidence of drooling. CONCLUSION: We recommend the use of the composite radial forearm-palmaris longus tendon free flap for this type of reconstructive surgery. Arch Facial Plast Surg. 2000;2:53-56

Aged↗
PubMedDate not supplied

Role of Epstein-Barr virus in fine-needle aspirates of metastatic neck nodes in the diagnosis of nasopharyngeal carcinoma.

BACKGROUND: The patient with nasopharyngeal carcinoma (NPC) frequently is initially seen with regional node dissemination. Preliminary investigations suggest that the presence of Epstein-Barr virus (EBV) genomes in neck metastases from an occult primary may be diagnostic and predictive of NPC. The goal of this study was to test this proposition. METHODS: The polymerase chain reaction (PCR) was used to detect the presence of EBV DNA in fine-needle aspirate (FNA) samples obtained from malignant neck nodes. Control samples were obtained from other locations in the head and neck. PATIENTS: The patients in this study were evaluated at the Toronto Princess Margaret Hospital, a province-wide tertiary-care cancer treatment center. Of the 23 patients evaluated with malignant neck masses, 6 had NPC, 5 patients had metastatic squamous cell carcinoma of an unknown primary, and 12 patients served as controls with other known head and neck carcinomas. One of the patients initially diagnosed as an unknown primary later demonstrated NPC. FNA specimens were also obtained from 24 normal parotid, submandibular, or thyroid glands for comparison. RESULTS: In the samples with sufficient DNA for analysis, EBV was detected in 5 of 5 neck nodes from patients with known NPC. EBV was also detected in the neck node of a patient who went on to develop NPC and in a cervical node from 1 of 2 patients in whom the primary tumor remained unknown. None of the evaluable control neck nodes of FNA controls from other sites demonstrated EBV. CONCLUSIONS: These results demonstrate the utility of NPC-diagnostic EBV gene amplification in FNA samples of neck metastases and suggest that the presence of the EBV genome in FNA samples of neck nodes is predictive of the presence of NPC.

Adolescent↗