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Biomedical subjects

S R Baker

Publications and source records attributed to S R Baker.

At least 127 records · Page 7Linked to original sources

An objective method for prediction of tracheoesophageal speech production.

Current methods of esophageal air insufflation testing to predict postoperative tracheoesophageal speech success lack procedural objectivity and rely on subjective interpretation of the voice production results. A range of intraesophageal pressure measurements was obtained prior to tracheoesophageal (TE) puncture in each of 27 laryngectomized patients in an attempt to predict TE speech outcome. Postoperatively, three levels of speech production were identified. Fluent speakers, nonfluent speakers, and nonspeakers demonstrated low, intermediate, and high intraesophageal pressures, respectively. Patients with intermediate and high preoperative pressures did not achieve fluent speech without myotomy. This technique offers a reliable, objective preoperative indication of expected TE speech fluency.

Aged↗

An interdisciplinary approach to the management of basal cell carcinoma of the head and neck.

At the University of Michigan the dermatologic surgeon works closely with the head and neck surgeon in resecting extensive cutaneous malignancies that could benefit from the combined skills of both surgical specialists. Mohs surgery offers complete microscopic controlled resection of the cutaneous portion of skin cancers. Tumors extending deeply from the skin into underlying bone and soft tissue are resected with the assistance of the head and neck surgeon familiar with the anatomy and trained in the protection of the vital structures of the head and neck. It is evident that patients with large or aggressive basal cell carcinomas will best be served when this interdisciplinary approach has become commonplace.

Basal Cell Carcinoma↗

Effects of leukotriene B4 inhalation. Airway sensitization and lung granulocyte infiltration in the guinea pig.

Male Hartley guinea pigs were exposed by inhalation to leukotriene B4 (LTB4) and challenged 5 min or 4 h later with bronchoconstrictive aerosols of histamine or the divalent cationic ionophore A23187. Pulmonary gas trapping measured in excised lungs indicated the severity of post-challenge airway obstruction. Airway granulocyte infiltration was scored by an observer who was unaware of animal assignments. Treatment with LTB4 produced a marked influx of eosinophils and neutrophils into tracheal and bronchial airways. Granulocyte scores for LTB4-treated groups were 1.9 to 3.3 times higher than those for vehicle-treated groups at 5 min after exposure and 3.3 to 10.7 times higher at 4 h after exposure. Leukotriene B4 itself did not produce hyperinflation. However, histamine-induced gas trapping was increased 5 min after LTB4 exposure. Histamine responsiveness was unaffected 4 h after LTB4 treatment. In contrast, A23187-induced gas trapping was unaffected at 5 min, but diminished at 4 h after LTB4. Nonchemotactic stereoisomers of LTB4 did not produce granulocyte influx, but did produce altered airway responses similar to those seen for LTB4. We conclude that inhaled LTB4 produces airway granulocyte infiltration in the guinea pig and alterations in airway responsiveness that vary with the challenge stimulus and time after exposure. Alterations in airway responses may result from granulocyte-independent effects of LTB4 and its stereoisomers.

Aerosols↗

Intra-arterial cisplatin and FUDR in advanced malignancies confined to the head and neck.

Twenty-seven patients with advanced malignancies confined to the head and neck region were treated with intra-arterial (IA) cisplatin and 5-fluorodeoxyuridine (FUDR) using implantable pumps or injection ports. Tumor histologies were: 16 squamous cell, one mucoepidermoid, one adenocarcinoma, one neuroendocrine, four adenoid cystic, two acinic cell, one fibrosarcoma, and one melanoma. All primaries originated from tissues in the head and neck area. Nineteen patients had received prior treatment, including chemotherapy in 13; eight were newly diagnosed. Responses in 26 evaluable patients were two complete (CR), ten partial (PR), six minor (MR), and eight progressions. The median duration of response was 5 months, with a range of 2 to 11 months. Sites of progression were within the infused volume in 13 patients and to uninfused local-regional or distant sites in eight. The response rate in the subset of 15 patients with squamous cell head and neck cancer was 47%. Toxicity in the 26 patients included stomatitis in 88%, nausea and vomiting in 64%, myelosuppression in 15%, and grade 1 nephrotoxicity in 1%. A regional advantage for IA cisplatin and FUDR can be calculated based on total body clearance rates (CLTB) for these agents and estimates of external carotid artery (ECA) blood flow. However, frequent progression of disease outside the infused volume to regional and distant sites limits the usefulness of this approach in recurrent disease patients.

Adult↗

Preoperative assessment of tracheoesophageal speech.

Air insufflation testing of tracheoesophageal (TE) puncture candidates as currently practiced lacks objectivity and relies on subjective evaluation of the sound produced. Intraesophageal pressure measurements were obtained from 21 consecutive laryngectomized patients during air insufflation by either experienced examiners or a compressed air source at 1 liter or 3 liters per minute. Postoperatively, three levels of TE speech fluency were identified. Preoperative intraesophageal pressure measurements were associated with a specific post-TE puncture speech fluency result. Intraesophageal pressure measurements may offer a reliable objective preoperative assessment of post-TE puncture speech fluency and identify patients who would benefit from pharyngeal myotomy at the time of TE puncture.

Aged↗

The effect of restricting the indications for lumbosacral spine radiography in patients with acute back symptoms.

A prospective study was performed to evaluate the effect of using a special requisition form on the utilization of lumbosacral spine radiography for patients presenting in the emergency room with acute lower back complaints. Over a 1-year period, emergency room house officers were encouraged to complete a special form that listed only three acceptable indications for lumbosacral spine radiographs: history of trauma, evidence of focal neurologic abnormality, and "other." Neurologic abnormalities included hypesthesia, hyperesthesia or anesthesia of lumbar or sacral dermatomes, weakness or hyporeflexia of the lower extremities, and bladder or bowel incontinence. If the indication "other" was chosen, radiographs were done only if the form contained both a one- to two-sentence history and the signed approval of a supervising attending physician. The number and results of lumbosacral spine examinations were compared with those from the previous year, which served as a control. In the control year 1443 examinations were performed, and in the experimental year only 759 were done (a decrease of 47%). The percentage of patients with vertebral fractures increased from 5.1% to 5.8% in the experimental year if only the detection of new fractures was considered positive, and from 9.1% to 13.4% if the detection of fractures of all ages was regarded as significant. The use of the special requisition form appears to be a simple and effective means of reducing unnecessary lumbosacral radiography in the emergency room setting.

Acute Disease↗

Radiology consultation.

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Hospital Bed Capacity, 500 and over↗

Radiographic abnormalities in coagulation factor VII deficiency.

We report the plain film findings as knees and elbows in two patients with congenital coagulation factor VII deficiency. The radiographic features resemble hemophilia, although the joint manifestations are milder, appear later in life, and occur in both men and women.

Adolescent↗

Microvascular free flaps in soft-tissue augmentation of the head and neck.

The disadvantage of traditional methods for reconstruction of soft-tissue deficits providing symmetric restoration of head and neck contour are the need for multiple stages in the case of pedicle flaps and the unpredictable atrophy and resorption in the case of free nonvascularized dermis-fat grafts. In addition, unsightly donor defects may be an added disadvantage. A major use of free revascularized grafts and flaps is in the reconstruction of contour defects of the head and neck resulting from loss of soft tissue and bone. Soft-tissue augmentation can be achieved by the transfer of free cutaneous or musculocutaneous flaps. The ideal donor sites for such flaps are in areas of the body where large direct cutaneous or musculocutaneous flaps can be harvested with relatively long vascular pedicles, and where minimum morbidity and secondary deformity will occur from harvesting the flap. Microvascular flaps allow for tissue augmentation of the head and neck with restoration of symmetry without the problem of subsequent atrophy and resorption.

Arteries↗

Surgical treatment of recurrent pleomorphic adenoma of the parotid gland.

Recurrent pleomorphic adenomas of the parotid gland warrant consideration because of the potential for facial nerve injury occurring with surgical treatment and the risk of malignant conversion. Forty-eight cases of recurrent pleomorphic adenoma treated at the University of Michigan, Ann Arbor, between 1935 and 1975 were retrospectively analyzed. The results of surgical procedures for recurrence were determined with respect to tumor control and resultant facial nerve function. Malignant conversion developed in three (6%) of 48 cases. The results of this study underscore the importance of adequate surgical excision of initial recurrences as well as primary tumors to prevent tumor recidivism. Tumor control rates and facial nerve preservation are enhanced with formal parotidectomy for recurrent tumor when feasible. In cases in which facial nerve identification and dissection is not possible, en bloc total parotidectomy offers effective, though not absolute, control of extensive recurrence.

Adenoma, Pleomorphic↗

Magnetic resonance imaging of the head and neck.

Magnetic resonance imaging (MR) has already gained wide acceptance in the evaluation of intracranial and spinal canal abnormalities. MR also provides excellent resolution of certain tumors of the head and neck and is particularly useful for the evaluation of neoplasms in the vicinity of the skull base. The absence of a bone signal prevents the streaking artifact so troublesome with computerized axial tomography (CT) and allows better definition of tumor. MR does not use ionizing radiation and appears to be an innocuous imaging mode--thus multiple examinations in young patients are not objectionable with MR. The ability to obtain images in multiple planes by control of the magnetic gradients allows for axial, sagittal, and coronal imaging, without changing the supine position of the patient. Multiple projections are helpful in providing better preoperative assessment of the extent and size of certain neoplasms of the neck.

Brain↗

Clinical implications of orbital cellulitis.

Periorbital and orbital cellulitis are clearly two distinct disorders with different etiologies. Periorbital cellulitis is well-documented as a more common infectious process limited to the eyelids in the preseptal region. In contrast, orbital cellulitis represents a more severe, but less common, infection of the orbit posterior to the septum with or without subperiosteal abscess, orbital abscess, or cavernous sinus thrombosis. A retrospective review of the clinical and laboratory data of 137 cases of orbital and periorbital cellulitis was performed. Periorbital cellulitis was documented in 98 cases (71%), in contrast to orbital cellulitis which was noted in 39 (28%) patients. All patients with orbital cellulitis received intravenous antibiotics, however, surgical therapy was necessary for progression of orbital cellulitis in 49% of patients. The majority of patients underwent incision and drainage of an abscess in the orbit. Complications as a result of orbital cellulitis occurred in nine (23%) of the patients. A distinction is made between the clinical entity of periorbital cellulitis and orbital cellulitis. Separating these clinical entities on the basis of physical examination and radiographic studies is important because the medical and surgical management of these two disease processes is different.

Abscess↗

Radiologic consultation: its application to an acute care surgical ward.

Over an 8-month period, all requests for imaging tests on an acute care surgical ward were discussed and approved by a radiologist who made daily rounds with the surgical staff. Compared with an equivalent interval before the start of the consultation service, the number of sonograms, CT scans, scintigrams, and barium studies decreased significantly, while the number of endoscopic procedures remained constant. The average length of stay was shortened by 2.8 days during the experimental period.

Adult↗

Tumor blood flow and systemic shunting in patients receiving intraarterial chemotherapy for head and neck cancer.

Radionuclide techniques have been used to estimate the systemic shunt and to quantitate blood flow to the tumor and a reference normal tissue in nine patients undergoing intraarterial chemotherapy for head and neck cancer. The systemic shunt was calculated as the percentage of pulmonary trapping of intraarterially injected 99mTc-labeled macroaggregated albumin. The mean systemic shunt in the 12 separate arteries studied was 23 +/- 13% (SE) (range 8-43%). Quantitative blood flow was determined from the slope of the washout curve of intraarterially injected 133Xe. The mean tumor blood flow was 13.6 +/- 6.7 ml/100 g/min, while the mean blood flow to the scalp was 4.2 +/- 2.1 ml/100 g/min providing a mean tumor/normal tissue ratio of 3.9 +/- 2.7. An estimate of blood flow distribution was obtained by calculating the ratio of counts/pixel in the tumor mass versus the remainder of the head as determined by single photon emission computed tomography following an intraarterial injection of 99mTc-labeled macroaggregated albumin. The mean ratio of tumor to normal tissue perfusion by this technique was 5.6 +/- 3.7. These techniques have allowed noninvasive determination of the blood flow parameters associated with intraarterial chemotherapy. At least part of the therapeutic advantage of regional chemotherapy in patients with head and neck cancer is due to a tumor/normal tissue blood flow ratio that favors drug delivery to the tumor contained within the infused volume.

Adult↗