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Biomedical subjects

C N Ford

Publications and source records attributed to C N Ford.

At least 37 records · Page 2Linked to original sources
PubMed1996

Muscle tension dysphonia and spasmodic dysphonia: the role of manual laryngeal tension reduction in diagnosis and management.

Excessive activity of the extralaryngeal muscles affects laryngeal function and contributes to a spectrum of interrelated symptoms and syndromes including muscle tension dysphonia and spasmodic dysphonia. Recognition of the role of extralaryngeal tension is helpful in ensuring proper diagnosis and selection of appropriate treatment. This report demonstrates the application of manual laryngeal musculoskeletal tension reduction techniques in the diagnosis and management of laryngeal hyperfunction syndromes. The manual technique consists of focal palpation to determine 1) extent of laryngeal elevation, 2) focal tenderness, 3) voice effect of applying downward pressure over the superior border of the thyroid lamina, and 4) extent of sustained voice improvement following circum-laryngeal massage. The clinical utility of this innovative approach is discussed.

Adult↗
PubMed1995

Magnetic resonance imaging (MRI) assessment of vocal fold medialization surgery.

Historically, clinicians have used subjective assessment and perceptual judgments, supplemented with acoustic measures, aerodynamic studies, and videostroboscopy, to determine the effects of phonosurgery. When phonosurgical results are poor, magnetic resonance imaging (MRI) can be useful in determining how the surgical modifications contributed to the anatomical and functional status of the vocal folds. The authors present examples of MRI following vocal fold medialization by injection, thyroplasty, and arytenoid adduction. Findings reveal that the superior contrast resolution of MRI can precisely identify placement and persistence of injected implants and is particularly helpful in showing effects of the size and shape of alloplastic prostheses on vocal fold displacement. Such information is useful in troubleshooting suboptimal results and in planning revision thyroplasty by defining modification in the design of prostheses and the placement of cartilaginous windows in medialization thyroplasty. MRI can also aid in confirming indications for and limitations of certain procedures.

Adult↗
PubMed1995

Autologous collagen vocal fold injection: a preliminary clinical study.

This preliminary study reports the first use of injectable autologous collagen for vocal fold augmentation. In previous studies, the authors showed cross-linked bovine collagen to be effective in more than 150 patients with glottic incompetence, particularly those with focal defects or scarred or atrophic vocal folds. However, concerns about possible adverse immunologic responses to the bovine material have limited its use. The authors studied eight patients with difficult vocal fold pathology, including sulcus vocalis, atrophy, and scarring secondary to trauma and cordectomy. Skin was harvested under local anesthesia, processed into a naturally cross-linked injectable form (Autologen), and injected using indirect laryngoscopy. Voice production was evaluated prior to the injection and at intervals after the injection, using subjective, perceptual, aerodynamic, acoustic, and videostroboscopic assessments. The results indicate that autologous collagen is comparable to injectable bovine collagen in the management of several difficult glottic insufficiency problems and that the likelihood of a hypersensitivity response is negligible. Unlike bovine collagen preparations, Autologen does not require breakdown of the natural collagen molecule, so it is anticipated that this material will be better tolerated and more stable over time.

Adult↗
PubMed1994

Evaluation and treatment of the unilateral paralyzed vocal fold.

The evaluation and treatment of patients with unilateral vocal fold paralysis have evolved as improvements in objective measurements of phonatory function and new modalities for treatment have developed. A thorough history, physical examination, subjective voice evaluation, objective voice analysis, and electromyography are used to make a diagnosis, determine the cause, and plan treatment. The goal of treatment of the patient with a unilateral vocal fold paralysis is to restore normal phonatory function without aspiration. Multiple modalities have developed to allow for restoration of nearly normal phonatory function, and these include voice therapy alone or in combination with injection medialization, laryngoplastic phonosurgery, or laryngeal reinnervation. Otolaryngologists should be familiar with the incidence, cause, evaluation, and state-of-the-art treatment of unilateral vocal fold paralysis of optimize patient care and avoid suboptimal results often seen with antiquated or inappropriate treatment.

Humans↗
PubMed1994

Sulcus vocalis in laryngeal cancer: a histopathologic study.

The incidental finding of sulcus vocalis in surgical specimens of patients with laryngeal cancer prompted this review. Sulcus deformities were histologically identified in 28 (48%) of 58 whole-mount coronal serial-sectioned laryngeal specimens procured from laryngeal cancer patients. The lesions were analyzed, described, and graded. A control group of 20 larynges, obtained from autopsies of patients without known laryngeal pathology, were similarly processed, and whole-mount histologic sections were studied. Four of these specimens (20%) also demonstrated sulcus deformities. In the control group, the shape and location of the sulci were similar, but the lesions were smaller than in the cancer group. The sulcus lesions revealed chronic inflammation of the subepithelial tissues with vascular ingrowth and fibrosis of the superficial lamina propria (Reinke's space); in the cancer group the sulcus was usually on the opposite vocal fold, where irritation from the tumor might be anticipated. Although the etiology of the sulci remains controversial, these findings suggest that irritation and inflammation might play a role in the pathogenesis of sulcus vocalis.

Female↗
PubMed1994

Anterior commissure microwebs associated with vocal nodules: detection, prevalence, and significance.

Vocal fold nodules are a common cause of dysphonia generally attributed to vocal abuse. Anterior commissure microwebs have been reported as an incidental finding in surgical patients with nodules. In a series of 105 nodule patients evaluated at the University of Wisconsin Clinical Science Center voice laboratory (1987-1992), 11 microwebs were identified. Ten of these microweb patients were among the 20 nodule patients who did not respond to voice therapy and underwent microsurgery. In patients with nodules whose hoarseness is refractory to voice therapy, symptoms that occur early in life suggest the presence of occult vocal fold pathology. Microweb detection requires a high index of suspicion, observation during maximal vocal fold abduction, and clearance of secretions from the anterior commissure. Definitive identification is facilitated by gentle separation of the anterior vocal folds during direct microlaryngoscopy. The presence of these tiny shelves of tissue might be coincidental, or they might represent another expression of the tissue response to traumatic factors known to produce vocal nodules. We found little difference in vocal function parameters between two similar groups of nodule patients, one with and one without associated microwebs. Further work is needed to determine the significance of microwebs.

Adolescent↗
PubMed1993

Dose intensification in curative head and neck cancer radiotherapy--linear quadratic analysis and preliminary assessment of clinical results.

PURPOSE: The feasibility of reducing overall treatment time by 2 weeks in the curative radiotherapeutic management of head and neck cancer patients is reported in a pilot trial of Hyperfractionated, Accelerated Radiotherapy with Dose Escalation (HARDE). This regimen prescribes 76 Gy in 5 weeks to definitive head and neck cancer patients, and 65 Gy in 5 weeks to high-risk postoperative patients. The linear quadratic model is used to compare predicted tumor cell kill with HARDE versus that expected with conventional fractionation (CF). MATERIALS AND METHODS: Between January 1991 and March 1992, 40 head and neck cancer patients were treated with HARDE at the University of Wisconsin Comprehensive Cancer Center. Case-matched controls treated with CF were identified from patients treated at the same institution between 1980-1990, based on tumor site, stage, and extent of prior surgery. Individual patient treatment data (total dose, fraction size, overall time) rather than idealized schedule data from each group were analyzed using the linear quadratic model. RESULTS: Seventy-nine case-matched controls were identified for comparison with HARDE patients. The predicted increase in log cell kill for HARDE patients over case-matched controls was 1.5 and 1.3 logs, respectively, in the definitive and postoperative settings. This difference in log cell kill projects an improvement in locoregional tumor control for HARDE patients of between 10-25%. HARDE patients experience very brisk acute mucosal reactions and moderately prolonged mucosal healing, however, 91% have completed therapy without a treatment break. CONCLUSION: A 2-week reduction in overall treatment time for curative head and neck cancer patients is feasible while maintaining doses > 70 Gy. Based on radiobiologic predictions, such treatment intensification may significantly improve rates of locoregional tumor control. However, intensified acute mucosal reactions accompany such accelerated therapy.

Case-Control Studies↗
PubMed1993

Teflon vocal fold augmentation: failures and management in 28 cases.

Although vocal fold augmentation by Teflon injection has been the mainstay of treatment for glottic insufficiency for three decades, the success and safety of this treatment have been overstated. Twenty-eight patients who manifested poor or complicated Teflon results between 1984 and 1991 were evaluated using acoustic, aerodynamic, videostroboscopic, perceptual, and subjective patient self-evaluation of voice, both before and after our management of these complications. Most of these had Teflon granulomas; subglottic overfilling was the most common condition. In most instances such management included microsurgical removal of the Teflon granuloma. Voice measures that were abnormal before correction tended to improve and move into the normal range, although the resultant voices were not totally normal. Degree of improvement varied depending on the Teflon-induced tissue changes and the methods of correction subsequently used. The worst results were in patients with scarring, atrophy, and bilaterally mobile vocal folds, for whom Teflon should never have been injected. Teflon injection should be reserved for those instances in which it is clearly indicated and the surgeon is skilled in the technique of intrafold injection.

Adult↗
PubMed1992

Role of injectable collagen in the treatment of glottic insufficiency: a study of 119 patients.

Injectable bovine collagen has been used for treatment of glottic insufficiency at the University of Wisconsin Clinical Science Center since 1983. This report reviews our experience in treating 119 patients with a variety of vocal fold disorders manifested by glottic insufficiency. Many of the patients were referred because of prior treatment failures or problems that were impossible to treat with other modalities. Results were assessed by comprehensive voice evaluations using subjective patient self-assessments, perceptual judgments made by a panel of experts who had no prior knowledge of the study, objective assessments, and videostroboscopy. Objective assessment included vocal function measures and acoustic analysis. Results indicate that collagen not only is comparable to other injection filler substances but also has unique advantages as a bioimplant. Collagen injection seems uniquely suited for treatment of several problems, including vocal fold atrophy, focal defects, minimal glottic insufficiency, and scarred vocal folds that are not managed optimally with Teflon injection. Overall there were no serious complications and treatment was effective for a broad spectrum of problems. In most instances the correction persisted, and in those instances in which injected collagen seemed improperly distributed, the vocal fold was recontoured or the implant removed without appreciable damage to the surrounding tissues. Injectable collagen has been extensively studied and deserves to be included in the armamentarium of the laryngeal surgeon.

Adolescent↗
PubMed1990

Indirect laryngoscopic approach for injection of botulinum toxin in spasmodic dysphonia.

Spasmodic dysphonia is a focal dystonia that causes a loss of the fine control of intrinsic laryngeal muscles and produces a strained staccato voice. Temporary relief from symptoms has been reported in patients treated with botulinum toxin percutaneously injected into the thyroarytenoid muscle. A newly developed method of treatment differs from reported methods by increasing the accuracy of botulinum toxin placement, reducing soft tissue trauma, and applying basic scientific information about the functional histology of intrinsic laryngeal musculature. Sixteen patients with primarily adductor spasmodic dysphonia were treated. Initial assessment included laryngeal examination by indirect laryngoscopy, videoendoscopy, and stroboscopy, neurology examination (including laryngeal EMG), and vocal function studies with acoustic analysis and aerodynamic studies. A device originally designed for collagen injection allowed the precise microdelivery of toxin to the thyroarytenoid muscle. Indirect laryngoscopy was used to direct the needle, in an attempt to cover a broad area of motor end plates. The minimally effective dose was titrated for each patient, to avoid paralysis and preserve laryngeal function. All patients showed improved voices after treatment. There were no major complications. The basic technique can be performed in the otolaryngologist's office and does not require electromyography equipment or expertise.

Adult↗
PubMed1990

Laryngeal electromyography in the diagnosis of laryngeal nerve injuries.

A practical technique of electromyographic (EMG) sampling of the cricothyroid and thyroarytenoid (vocalis) muscles is described. Quantitative motor unit action potential (MUAP) analysis on a group of seven healthy subjects revealed a mean amplitude of 426 microV for the vocalis and 500 microV for the cricothyroid muscle. Mean MUAP duration for the vocalis muscle was 3.5 msec and 4.4 msec for the cricothyroid. Normal activation patterns are reviewed for each muscle. The results of EMG studies in 18 consecutive patients referred to the EMG laboratory with chronic hoarseness was reviewed. There was good agreement between findings at laryngoscopy and EMG, although more widespread involvement was seen on EMG than was suspected on the basis of laryngoscopy. Vocal cord immobility (apparent paralysis) was not usually accompanied by the total absence of MUAPs. The procedure was well tolerated without local anesthesia and provides information about peripheral nerves which may be of prognostic value.

Action Potentials↗
PubMed1987

Persistence of injectable collagen in the human larynx: a histopathologic study.

This is a report of the histologic findings in a human larynx that had undergone collagen injection for glottic insufficiency 14 months prior to autopsy. The patient's management before augmentation with collagen included extended supraglottic laryngectomy, radiation therapy, and Polytef injection. Connective tissue changes secondary to other forms of treatment were apparent bilaterally and changes limited to the site of collagen injection were identified. There have been reports of persistence of injected collagen in the canine larynx at 1 year but this is the only study documenting persistence in a human subject. The implant appeared homogeneous and was easily distinguished from host collagen and the reactive fibrosis associated with particulate Polytef. These findings are similar to those observed in the canine model and suggest that there is persistence of injected collagen in the human larynx.

Collagen↗
PubMed1986

Histologic studies on the fate of soluble collagen injected into canine vocal folds.

Collagen is an essential component of the functionally important layered structure of the vocal cord. Soluble bovine collagen appears to be suitable for injection into vocal folds to correct glottic insufficiency. Clinical trials and preliminary laboratory studies with the canine larynx indicate that injectable collagen is safe, effective, easily injected, and well-tolerated. Bovine collagen softens scar tissue, attracts the ingrowth of host fibroblasts, and allows the eventual replacement of the implant by new host collagen. This study examines the fate of collagen injected into canine vocal folds. Two forms of soluble bovine collagen, differing only in the amount of chemically induced cross-linkage, were injected into vocal folds of dogs; the animals were then killed at 12-week intervals for 1 year. Gross and histologic examination showed that both substances tended to be resorbed when injected deeply in the vocalis muscle, but persisted when injected in the plane of the vocal ligament - a site normally composed of dense collagen. The invasion of the implant by active host fibroblasts and the secondary deposition of new host collagen were evident in histologic sections. Examination with polarized light confirmed the presence of birefringence characterizing host collagen. The invasion of fibroblasts and deposition of new collagen in the implant were seen with electron microscopy. Cellular invasion seemed to progress more rapidly in the cross-linked preparation. Injected collagen did not evoke a foreign body reaction in any specimen studied, and was well-tolerated during replacement by host tissue.

Animals↗
PubMed1986

Clinical experience with injectable collagen for vocal fold augmentation.

Injectable collagen appears to be safe and effective in treating glottic insufficiency. Fifty-four patients received vocal-fold injections of Zyderm Collagen Implant and their responses were followed for as long as 2 years. Videostroboscopy affords the best assessment of glottic function and correlates well with vocal quality. Maximum phonation time and transglottic airflow are the most sensitive measures of glottic efficiency; follow-up studies indicate that responses to treatment vary at 1 week, tend to stabilize by 3 months, and show only slight decrement over 1 year. One patient experienced a delayed hypersensitivity reaction, but it did not adversely affect his result. The use of cross-linked preparations of collagen should decrease the incidence of such responses. Treated patients were divided into diagnostic groups. Patients with bilaterally scarred vocal folds did not appear to respond optimally to collagen injection. Vocal rehabilitation was better if patients had at least one normal vocal fold. The best results occurred in patients with unilateral vocal fold paralysis and pre-existent bowing or atrophy did not affect these results. Collagen should be injected in the plane of the vocal ligament for best results; if the injection is too deep the implant is resorbed, and if too superficial, vocal-fold vibration is impaired.

Collagen↗
PubMed1986

A preliminary study of injectable collagen in human vocal fold augmentation.

Soluble bovine collagen was injected for vocal fold augmentation in 27 patients with glottic insufficiency. Preliminary observations show that glottic closure was enhanced in all patients with no serious complications. Subjective and objective measures of vocal efficiency indicated improvement with reduction in airflow, improved glottic closure, and increased vocal intensity. Recent studies that reveal distant migration of injected Teflon suggest the need for the development of a safe biologic material for soft tissue augmentation. Collagen appears to satisfy criteria as an ideal bioimplant, tends to soften scar tissue, and is structurally similar to natural collagen in the human vocal fold. Further longitudinal studies and the development of potentially more stable cross-linked collagen preparations seem indicated.

Adult↗