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Biomedical subjects

B L Wenig

Publications and source records attributed to B L Wenig.

At least 37 records · Page 2Linked to original sources
PubMed1993

Analysis of air flow patterns in the human nose.

The nasal cavity is the main passage for air flow between the ambient atmosphere and the lungs. A preliminary requisite for any investigation of the mechanisms of each of its main physiological functions, such as filtration, air-conditioning and olfaction, is a basic knowledge of the air-flow pattern in this cavity. However, its complex three-dimensional structure and inaccessibility has traditionally prevented a detailed examination of internal in vivo or in vitro airflow patterns. To gain more insight into the flow pattern in inaccessible regions of the nasal cavity we have conducted a mathematical simulation of asymmetric airflow patterns through the nose. Development of a nose-like model, which resembles the complex structure of the nasal cavity, has allowed for a detailed analysis of various boundary conditions and structural parameters. The coronal and sagittal cross-sections of the cavity were modeled as trapezoids. The inferior and middle turbinates were represented by curved plates that emerge from the lateral walls. The airflow was considered to be incompressible, steady and laminar. Numerical computations show that the main air flux is along the cavity floor, while the turbinate structures direct the flow in an anterior-posterior direction. The presence of the turbinates and the trapezoidal shape of the cavity force more air flux towards the olfactory organs at the top of the cavity.

Humans↗
PubMed1993

The lateral arm free flap for head and neck reconstruction.

The lateral arm free flap has proved to be both a versatile and successful method of reconstruction. Since its introduction a decade ago, however, its application in head and neck reconstruction has been fairly limited. Dissection of the flap, based on the posterior radial collateral branch of the profunda brachii artery, is relatively simple and provides a thin, dependable flap that has the potential to be used as a osteocutaneous flap or as a fasciocutaneous flap alone. The flap contains a sensory nerve that is readily anastomosed and donor site morbidity is limited. Although the pedicle is short, several modifications exist that allow its extension. This flap has been used successfully to reconstruct various defects in the head and neck. Pertinent anatomy, indications, and guidelines for clinical application will be discussed.

Adult↗
PubMed1993

A comparison of suture versus laser-assisted microvascular anastomosis (LAMA) in the pig buttock flap model.

Introduction of microvascular free-tissue transfer to head and neck surgery has completely altered the current approach to extirpation and reconstruction. The increased flexibility now available offers multiple options for reconstruction and has essentially removed the limitations of size and geometry which existed with other types of repair. Despite these advantages, increased surgical time and potential flap failure loom as limiting factors. Since the initial use of sutures to perform microvascular anastomoses, numerous experiments have been conducted in order to identify other options for vessel approximation. Laser-assisted microvascular anastomosis (LAMA) was first attempted with the neodymium-yttrium aluminum garnet (Nd:YAG) laser and, subsequently, other wavelengths were used in experimental models. Success with this technique has been repeatedly documented. Although a comparable animal model to study skin flaps was initially described in 1979, little is currently available in the literature that describes the actual use of a microvascular free flap model. Certainly, nothing exists regarding the role of LAMA and microvascular free-tissue transfer. This study was designed to establish a reliable and reproducible animal model to study free-tissue transfer. Through the use of laser Doppler flowmetry, values of blood perfusion of flaps can be determined. Anastomoses with standard suture and various laser-assisted techniques could then be done and compared, analyzing the parameters of time and blood flow. Histologic evaluation could be correlated with clinical observations. In so doing, LAMA could be objectively evaluated as a potentially viable method of vascular reconstruction in microsurgical free-tissue transfer.

Anastomosis, Surgical↗
PubMed1992

Complications of percutaneous endoscopic gastrostomy in head and neck cancer patients.

Percutaneous endoscopic gastrostomy (PEG) has been shown to benefit patients with resectable carcinoma of the head and neck. In order to determine whether patients with existing tumor or postresection anatomic changes of the upper respiratory tract can undergo this procedure with an acceptably low complication rate, 349 patients with attempted PEG were studied. The PEG procedure was successful in 114 of 122 carcinoma patients, as compared to 220 of 227 patients in a control group (patients with neurologic disease). Intraoperative complications preventing PEG placement included pharyngeal or esophageal obstruction, inadequate transillumination of the abdominal wall, and respiratory distress and occurred in 7% of carcinoma patients and 3% of controls. The incidence of airway obstruction during endoscopy was equal between groups (1%). Postoperative complications related to the gastrostomy tube were more frequent in the non-head and neck cancer group (14% versus 5%). Younger age, fewer concomitant medical problems, and better nutritional status may account for this difference. These findings suggest that preoperative, postoperative, and unresectable head and neck cancer patients are appropriate candidates for PEG, and postgastrostomy performance appears superior to that in other patient populations.

Aged↗
PubMed1992

Percutaneous endoscopic gastrostomy in the management of head and neck carcinoma.

In patients undergoing resection of head and neck malignancies, structural and functional deficits commonly preclude adequate oral nutrition and prolong hospital stay. To address this issue, the benefit of routine preoperative placement of percutaneous endoscopic gastrostomy (PEG) was studied in a group of these patients. The postoperative course of 89 patients undergoing primary resection of advanced (stage III and IV) squamous cell carcinomas of the upper aerodigestive tract was examined. The hospital stay was reduced by up to 61% with PEG compared to hospital stay with standard nasogastric tube (NGT) alimentation. The difference was statistically significant for primary sites involving the larynx and pharynx, but not for lesions of the oral cavity. For tongue base tumors, there was a trend toward reduced hospitalization which did not reach statistical significance. The fistulization rate was unchanged. The complication rate for PEG was 5%, and morbidity was less with PEG than with NGT. The authors recommend the preoperative placement of PEGs for all patients with advanced carcinomas of the larynx, hypopharynx, and oropharynx.

Adult↗
PubMed1991

The submandibular triangle in squamous cell carcinoma of the larynx and hypopharynx.

A 15-year retrospective analysis was carried out at the University of Illinois College of Medicine, Chicago, reviewing the tumor staging and pathology data of 239 patients treated for carcinoma of the larynx and hypopharynx requiring laryngectomy alone, laryngectomy with neck dissection, or laryngopharyngectomy and neck dissection. Surgery was the primary treatment modality in 205 of the 239 cases, with the remaining 34 having surgery to treat radiation therapy failure. Primary tumors were located within the supraglottic region, the glottic region and, less commonly, the pyriform sinus. Ninety-five of the 239 patients either presented with or developed nodal metastases following initial treatment. Of these, only two had tumors within the lymph nodes of the submandibular triangle. This data corroborates impressions that tumors of the larynx and hypopharynx rarely metastasize to the submandibular triangle and that sparing this area during neck dissection for lesions of the larynx would seem justified.

Carcinoma, Squamous Cell↗
PubMed1991

Indications for and techniques of tracheotomy.

Although the operation has been practiced for centuries, the modern technique of tracheotomy was introduced and popularized in the beginning of the 20th century. The initial indication for tracheotomy was limited to impending airway obstruction resulting from trauma, but current indications are broader. Tracheotomy is one of four methods available to intubate the trachea and is associated with physiologic changes that are dependent on the duration of tracheotomy. Although surgical in nature, it is employed to relieve or prevent airway obstruction and to offer ventilatory support. Tracheotomy may be performed as an elective or an emergency procedure. Ideally, it is done in a controlled situation. However, when performed in an emergency setting, variations of the procedure, such as minitracheotomy or cricothyroidotomy, may be temporarily substituted. Preferably, tracheotomy is performed in an operating room; however, it may be carried out successfully in an intensive care unit as well.

Airway Obstruction↗
PubMed1991

Management of panfacial fractures.

Panfacial injuries are those that involve trauma to the lower, middle, and upper facial bones. They often are accompanied by multisystem- or polytrauma and require a team approach for management. Although stabilization of the overall status of the patient takes precedence, early and total restoration of facial form and function should be the goal of the maxillofacial surgeon.

Airway Obstruction↗
PubMed1990

Photodynamic therapy in the treatment of squamous cell carcinoma of the head and neck.

Photodynamic therapy is an experimental modality for tumor treatment based on the combined action of the tumor-localizing agent, ie, hematoporphyrin derivative, and red light. From 1985 through 1989, 26 patients were treated using hematoporphyrin-derived drugs and 630-nm light delivered by a tunable dye laser. All patients had biopsy-proved squamous cell carcinoma of the head and neck, and they had either failed the traditional treatment modalities or refused conventional therapies. Histological complete responses were achieved in 20 (77%) of 26 patients and partial responses in 5 (19%) of 26 patients for periods up to 48 months. Only minimal toxic reaction was noted in the group. As a guide to treatment planning for a patient group with large tumors, we used an optical dosimetry model based on tissue optics. The rate of complete responses to this treatment was 8 (73%) of 11. Our data indicate that photodynamic therapy is capable of inducing significant clinical and histological responses in the majority of those treated, and in some patients a prolonged response is produced. In certain select head and neck malignancies, photodynamic therapy has an important role as a treatment modality.

Aged↗
PubMed1990

Epiglottic laryngoplasty for repair of blunt laryngopharyngeal trauma.

Two unique cases of blunt laryngopharyngeal trauma are presented in which identical injuries were sustained to the supraglottic larynx and hypopharynx. Examination of the patients included the use of magnetic resonance imaging to help define the extent of injury. A successful outcome was achieved in each instance by employing the reconstructive technique of epiglottic laryngoplasty to repair the mucosal defects.

Accidents, Traffic↗
PubMed1989

Microvascular free flap reconstruction for head and neck defects.

In a three-year period, 53 microvascular free-tissue grafts were performed on 51 patients to repair defects following major head and neck ablative surgery or trauma. The vast majority were done at the time of tumor resection. The remainder were done as secondary operations after resection or injury. The choice of free flap was dictated by the reconstructive needs of the patient and donor site availability. Fifty-two (98%) of 53 free-tissue transfers were successful with one failure resulting from venous thrombosis. Complications were noted in 16 of 53 flaps. The majority of these complications were in flaps used to replace bony defects or oropharyngeal resections. Although free flaps may appear to be more risky than traditional forms of reconstruction, they offer the surgeon a greater spectrum of reconstructive options. Limitations of the use of free flaps result only from lack of technical skills and specialized equipment.

Adult↗
PubMed1989

Evaluation of reconstructive techniques of oropharyngeal defects.

Despite recent advances in radiation therapy and chemotherapy, surgical procedures remain the primary modality of head and neck cancer therapy. Adequate surgical resection frequently requires the removal of significant amounts of tissue. The primary concern of the reconstructive surgeon is the restoration of a functional aerodigestive tract. In addition to the prolongation of life, the quality of that life should be taken into consideration. The records of 25 patients undergoing oropharyngeal reconstruction for tumors stage 3 or 4 in the 4-year period from 1983 to 1986 were reviewed. After surgical extirpation, reconstruction was performed using either a pectoralis major musculocutaneous flap or a microvascular free flap. Results were evaluated with emphasis on both the intraoperative and postoperative course. The length of the procedure, time of initiation of oral feedings, time of decannulation, postoperative complications, time of discharge, and quality of life after discharge were considered. Those patients reconstructed with microvascular free flaps were able to tolerate oral feedings sooner and were discharged sooner than those patients reconstructed with pectoralis musculocutaneous flaps. In addition, the patients with pectoralis flaps were twice as likely to have local complications (e.g., superficial wound infection, fistula) as those with free flaps. The quality of the patient's life with respect to deglutition and intelligibility of speech was likewise better for those patients reconstructed with microvascular free flaps. The explanation of these results is presented.

Abdominal Muscles↗
PubMed1989

Voice restoration following laryngectomy: the role of primary versus secondary tracheoesophageal puncture.

A protocol was established at our institution to compare a series of primary and secondary tracheoesophageal punctures using the Singer-Blom voice prosthesis. Over a 24-month period, 20 primary and 18 secondary punctures were performed. Voice production, fluency of voice, and functional use were graded. Our data support the use of both primary and secondary voice restoration following laryngectomy.

Adult↗
PubMed1989

Voice restoration after laryngopharyngoesophagectomy.

Although various methods of alaryngeal communication after laryngectomy have been described, little attention has been given to voice restoration after laryngopharyngoesophagectomy. This article deals with our experience reconstructing the hypopharynx and cervical esophagus in five patients by the use of microvascular free tissue grafts. Voice restoration procedures with use of a Blom-Singer prostheses were used uniformly and resulted in the attainment of functional voice in each patient. It is our feeling that this method should be used equally in patients undergoing both traditional laryngectomy and laryngopharyngoesophagectomy.

Adult↗
PubMed1989

Potential use of in vivo proton spectroscopy for head and neck lesions.

Early experience with in vivo MRS has shown its potential for obtaining biochemical information, thus enhancing the diagnostic sensitivity of MRI studies. Further work on combined MRI and in vivo MRS is needed, with the goal of characterization and abnormal conditions according to their spectral patterns and for identification of tumor markers. We presented in this communication our preliminary results. It seems that the resonance from melanin can be used as a marker for melanotic tumors.

Biomarkers, Tumor↗