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Biomedical subjects

J A Kirchner

Publications and source records attributed to J A Kirchner.

90 records · Page 5Linked to original sources
PubMedDate not supplied

Effect of microaerosol inhalation on the pattern of breathing.

Microaerosol stimulation of the trachea and bronchi appears to have no effect on the pattern of breathing. However, laryngeal stimulation with microaerosol produces consistent changes characterized by slowing of the inspiratory effort. The reflex response can be abolished by either bilateral superior laryngeal nerve section or topical anesthesia of the laryngeal mucous membranes. Nasal stiumulation with saline microaerosol results in marked slowing of inspiration. This response can also be blocked by topical anesthesia of the nasal mucosa. The decreased breathing rate results from both increased t insp. and t exp. During inspiration the build-up phrenic discharge activity, the phrenic slope, decreases. The phrenic peak, however, remains unchanged. The nose and larynx, therefore, appear to play significant roles in the modification of the breathing pattern in response to a nonirritating solution delivered as a microaersol. Slower breathing, relexly produced in the human being by such a method, might benefit partial airway obstruction by reducing turbulence and therefore the work of breathing. It is speculated that in a marginally competent upper airway, this benefit might be a critical factor in survival.

Aerosols↗
PubMedDate not supplied

Pyriform sinus cancer: a clinical and laboratory study.

In our patient population, cancer of the hypopharynx arose 19 times as often in the pyriform sinus as in the postcricoid space (152:8). Most of the growths were far advanced when first seen (90% T3), and enlarged cervical nodes were present in 66% of the patients. Three year survival rates free of disease were as follows: primary surgical treatment (laryngectomy, radical neck dissection) (8/28) 29%; primary radiotherapy (2/55) 4%; and combined preoperative radiation (12/33) 36%. Serial section studies of 51 surgical specimens indicate that T1 and T2 lesions, especially those confined in the medial wall, are probably curable by radiotherapy. Larger lesions invade deeply into the larynx and resemble transglottic growth in their pattern of spread. Conservation surgery would have been inadequate for all but perhaps one growth in this series of 51 lesions, because of the high rate of invasion by cancer into and through the thyroid cartilage and cricoid ring (22/51). Although surface presentation of this group of pyriform sinus cancers rarely reflected the extent of invasion, each of the 22 growths that invaded portions of the thyroid or cricoid cartilages was characterized by clinical involvement of the apex and lateral wall of the pyriform sinus on laryngoscopy or barium swallow.

Female↗
PubMedDate not supplied

Vocal cord positioning by selective denervation. Old territory revisited.

Vocal cord positioning produced by selective laryngeal denervation remains a controversial issue in clinical laryngology. Previous studies fail to arrive at uniform conclusions for two important reasons: 1) failure to mark a reference sagittal plane from which to assess the degree of vocal cord lateralization, and 2) failure to recognize the influence of tracheostomy and respiratory positioning of the vocal cords. The present study makes use of photographic and electromyographic documentation in the assessment of the paralyzed cord. Physiologic inactivation of the cricothyroid muscle by tracheostomy is a key determinant of the lateralized cord observed in acute low vagal and recurrent nerve paralysis. Tracheostomy-related cricothyroid inactivation cannot be ignored as a major determinant of cord positioning in paralysis and should not be overlooked in determining the neuroanatomic site of injury.

Animals↗
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Pathways and pitfalls in partial laryngectomy.

Some 350 surgical specimens obtained at partial or total laryngectomy were photographed immediately after operation and processed for study by serial section. Intralaryngeal barriers to the spread of cancer are demonstrated on one hand and pathways of infiltration and destruction on the other. The following conclusions are based on these studies: two major elastic tissue barriers that influence the spread of vocal cord cancer are the dense mass of connective tissue at the anterior commissure which prevents invasion of the thyroid cartilage until very late, and the conus elasticus, under which vocal cord cancer may advance subglottically under the intact overlying mucosa. This conceals the actual extent of cancer below the glottis and is the usual cause of local recurrence after hemilaryngectomy. A large subglottic component of a glottic or transglottic cancer is sometimes associated with extension of disease within the cancellous interior of the thyroid ala or cricoid ring under an intact mucosa. A large ventricle or saccule may harbor the bulk of a glottic cancer under an intact ventricular band. Hemilaryngectomy is usually contraindicated once the extent of such a tumor is recognized. Removal of the hyoid bone is rarely necessary at horizontal supraglottic partial laryngectomy. Its preservation facilitates postoperative deglutition. Partial laryngectomy should not be attempted for pyriform sinus cancer if inspection reveals involvement of the apex.

Glottis↗
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Prosthetic replacement of bilateral maxillectomy.

A patient had an adenocystic carcinoma that involved both maxillary sinuses, the entire hard palate, and the lower third of both nasal chambers. Treatment consisted of bilateral maxillectomy and a split-thickness skin graft applied to the inside of the cheeks. A dental obturator constructed to fit undercuts in the surgical cavity allowed speech and swallowing. Because the patient objected to the sunken appearance of the upper lip, she obtained the central incisor portion of her late husband's upper denture and bonded this segment to the dental appliance. This achieved satisfactory cosmesis.

Aged↗
PubMedDate not supplied

Intrathoracic injury to the motor nerve supply of the larynx.

A previously reported experimental study demonstrated that the intermediate (partly abducted) position of a paralysed vocal cord may be due to physiological inactivation, rather than paralysis, of the cricothyroid muscle. This inhibition was shown to be caused by interruption of vagal afferent impulses originating in pulmonary pressure receptors. The case reported here offered an unusual opportunity of studying this condition by serial section of a human larynx. A patient's left vocal cord was paralysed by cancer in the left pulmonary hilum and apex. There was aspiration and loss of voice. The larynx was obtained at autopsy and studied by serial sections. These showed that the P.C.A- muscle on the paralysed side was, in fact, completely atrophic and degenerated, as were the other intrinsic muscles but that the cricothyroid muscle was morphologically normal. Invasion of both the recurrent laryngeal nerve and the vagus at the thoracic inlet interrupts afferent impulses and inactivates the cricothyroid muscle, with resultant glottic incompetence.

Aged↗
PubMedDate not supplied

Intralaryngeal barriers to the spread of cancer.

Serial section studies were made of 412 surgical specimens removed by partial or total laryngectomy for laryngeal cancer. All sections were stained with hematoxylin and eosin. Selected sections were also stained for elastic tissue. Patterns of growth and spread of cancer within the larynx were found to be influenced by fibro-elastic ligaments and membranes which confined the tumor to anatomic compartments, and which provide margins of safety when performing partial laryngectomy.

Humans↗