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Biomedical subjects

Eric M Genden

Publications and source records attributed to Eric M Genden.

At least 37 records · Page 2Linked to original sources

Reconstruction of the hard palate using the radial forearm free flap: indications and outcomes.

BACKGROUND: Although prosthetic obturation is the "gold standard" for restoration of hard-palate defects, obturators can be problematic. We present 10 cases of palatal reconstruction with the radial forearm free flap and compare patient satisfaction with defect-matched patients rehabilitated with prosthetic obturation. METHODS: Twelve patients who underwent radial forearm free flap (RFFF) reconstruction of a hard-palate defect and eight patients, with similar-sized defects who were rehabilitated with a prosthetic obturator, were evaluated for donor site and recipient site complications, diet, and patient satisfaction. RESULTS: All the patients in both groups were able to resume an unrestricted diet with normal mastication and articulation. Both groups achieved equivalent satisfaction scores with regard to appearance, chewing, and taste; however, the patients reconstructed with an RFFF reported higher satisfaction scores in speech, comfort, convenience, and social interaction. CONCLUSIONS: RFFF reconstruction of hard-palate defects provides a functional alternative to conventional prosthetic obturators.

Female↗

Sensory topography of the oral cavity and the impact of free flap reconstruction: a preliminary study.

BACKGROUND: The purpose of this prospective randomized study was to (1) assess the computerized pressure-specific sensory device (PSSD) as a tool for measuring oral cavity sensation, (2) establish a topographic sensory map of the oral cavity, and (3) objectively evaluate postoperative sensory recovery of noninnervated oral cavity free flap reconstruction. METHODS: Twenty-three healthy control subjects were recruited to test four intraoral sites and the volar forearm. Sensory scores were evaluated for consistent trends between an established sensory tool, the Semmes Weinstein Monofilament (SWM), and the PSSD. Sensory control values were then compared with those of 18 patients who underwent reconstruction of the oral cavity with a noninnervated microvascular free flap. RESULTS: The SWM testing demonstrated the lowest sensory thresholds in the lower lip, followed by the lateral tongue, buccal mucosa, and central tongue. The PSSD also demonstrated the lowest sensory thresholds in the lower lip followed by the lateral tongue; however, the central tongue demonstrated a lower sensory threshold than did the buccal mucosa. The neotongue of patients with noninnervated free flaps demonstrated inferior sensation compared with the native tongue (p < .05). CONCLUSIONS: We have established normal sensory values for the oral cavity, skin of the volar forearm, and noninnervated free flap tissue within the oral cavity. Although discrepancies exist between the data derived from the SWM and the PSSD, the PSSD represents a reliable, sensitive, and easy method for assessing sensation of the oral cavity. Furthermore, PSSD testing is not affected by saliva or movement.

Adult↗

Complications of free flap transfers for head and neck reconstruction following cancer resection.

The reported success rate of microvascular free flap reconstruction ranges between 95% and 97%. However when complications occur, they must be identified early and managed efficiently because there is a narrow window of opportunity to salvage potential flap failure. While technical advances in instrumentation and magnification have improved overall success rates, the rare complication may prove devastating for the patient, his/her hospital stay, and the optimum rehabilitation. Complications of microvascular free tissue transfer may occur at the recipient site or at the donor site. Complications occurring at the recipient site are largely a result of vessel thrombosis while complications occurring at the donor site may result from many causes, ranging from infection to those related to the harvesting of the flap. Irrespective of the site of the complication, it is essential that complications be recognized and addressed early in their course to prevent or minimize devastating consequences.

Graft Rejection↗

Effect of fibrin matrix and vascular endothelial growth factor on reepithelialization of orthotopic murine tracheal transplants.

To determine whether the administration of vascular endothelial growth factor (VEGF) alone and in combination with fibrin matrix accelerates murine tracheal allograft reepithelialization, we randomly assigned 40 age-matched mice to 5 experimental groups. BALB/c tracheal grafts were transplanted orthotopically into allogeneic C57BL/6 recipients. The recipients were immunosuppressed with cyclosporine (25 mg/kg per day) and treated with a single topical dose of fibrin matrix, a single topical dose of VEGF, or a single topical dose of a combination of VEGF and fibrin matrix. Thirty-five and 50 days after transplantation, a mixed lymphocyte reaction was performed to assess adequate immunosuppression and the grafts were assessed for rejection, rate and quality of allograft reepithelialization, and cartilage viability. The administration of a combination of fibrin matrix and VEGF to tracheal allografts demonstrated an increased rate of reepithelialization and increased density (37% +/- 2.9%) of morphologically normal ciliated pseudostratified epithelium when compared with an immunosuppressed control group (29.3% +/- 9.1%) 35 days after transplantation. The treated allografts demonstrated no significant change in cartilage viability or rejection. We conclude that the administration of fibrin matrix and VEGF to immunosuppressed tracheal allografts improves the rate and density of tracheal allograft reepithelialization. Carrier-bound growth factors may represent a novel approach to accelerating tracheal allograft reepithelialization and decreasing the need for prolonged immunosuppression following tracheal transplantation.

Animals↗

Orthotopic tracheal allografts undergo reepithelialization with recipient-derived epithelium.

BACKGROUND: While the rejection of heterotopic tracheal allografts is characterized by complete airway obliteration, the rejection of orthotopic allografts leads to airway edema and cellular infiltrate of the lamina propria, but is not associated with obliteration. We hypothesized that orthotopic tracheal allografts undergo reepithelialization with recipient-derived mucosa and that this process prevents airway obliteration. METHODS: Thirty mice were randomly assigned to 6 experimental groups. BALB/c donor tracheal segments were transplanted orthotopically or heterotopically into syngeneic BALB/c or major histocompatability mismatched allogeneic C57BL/6 recipients. Recipients of allogeneic grafts were divided into a nonimmunosuppression group and an immunosuppression group (cyclosporine, 7 mg/kg per day). Twenty-one days after transplantation, histological assessment, immunohistochemistry for CD4 and CD8 lymphocyte infiltration and major histocompatibility-specific immunohistochemistry were performed on the grafts to assess rejection and donor or recipient origin of tissue. RESULTS: Untreated heterotopic allografts underwent complete airway obliteration by day 21. This response was prevented with cyclosporine immunosuppression. Untreated orthotopic allografts, however, demonstrated edema and lymphocytic infiltrate of the lamina propria resulting in clinical stridor without airway obliteration. Immunosuppressed orthotopic allografts did not develop edema or infiltrate of the lamina propria and consequently stridor did not occur. Immunohistochemical analysis demonstrated migration of recipient-derived mucosa into the donor allograft segment in both the untreated and treated orthotopic groups. CONCLUSIONS: Airway obliteration characteristic of rejecting heterotopic tracheal allografts does not occur in the orthotopic allografts. Migration of recipient mucosa into the donor allograft appears to prevent airway obliteration in the orthotopic allografts. These findings suggest that the orthotopic tracheal transplantation model more accurately represents the biological behavior of clinical tracheal allografts than the traditional heterotopic model.

Airway Obstruction↗

Comparison of functional and quality-of-life outcomes in patients with and without palatomaxillary reconstruction: a preliminary report.

BACKGROUND: Orodental rehabilitation of hemipalatomaxillectomy defects can be accomplished by using a prosthetic obturator or a vascularized bone-containing free flap. Whereas prosthetic obturation offers several advantages, including the opportunity for immediate dental restoration without the need for further surgery, vascularized bone grafts provide permanent closure of the oronasal communication and bone sufficient for the placement of osseointegrated implants. OBJECTIVE: To compare the functional and quality-of-life (QOL) outcomes in patients rehabilitated with a prosthetic obturator with defect-matched patients who underwent reconstruction with a vascularized bone-containing free flap. METHODS: Four hemipalatomaxillectomy patients rehabilitated with a tissue-borne prosthetic obturator were compared with 4 defect-matched hemipalatomaxillectomy patients who underwent reconstruction with a vascularized bone-containing free flap. All of the patients were objectively assessed for speech, mastication, and QOL. Functional status was assessed by mastication testing, voice analysis, and nasorhinometry. Swallowing-related QOL was assessed using a patient-reported, validated swallowing QOL questionnaire, and donor site morbidity was assessed using upper extremity and lower extremity questionnaires. RESULTS: Patients who underwent reconstruction with a vascularized bone-containing free flap achieved higher mastication and speech assessment scores with less oronasal reflux than defect-matched patients rehabilitated with a prosthetic obturator. Swallowing QOL and donor site assessments demonstrated that compared with their prosthetic counterparts, reconstruction patients enjoyed a better QOL without incurring significant donor site morbidity. CONCLUSIONS: Although palatomaxillary reconstruction with vascularized bone-containing free flaps requires a second operative site, this method of orodental rehabilitation of the hemipalatomaxillectomy defect can achieve superior functional and QOL outcomes relative to defect-matched patients rehabilitated with a prosthetic obturator.

Humans↗

Current philosophy on the management of cancer of the base of the tongue.

Cancer of the base of the tongue is a challenging disease for the head and neck surgeon, radiation oncologist and medical oncologist. However, over the last 10-15 years, improved treatment strategies have evolved which offer patients high probability of loco-regional control, survival, and good quality of life. The ability to offer patients good oncologic and functional outcomes serves as a paradigm for the successful application of multidisciplinary care, and the emphasis on quality of life in head and neck cancer treatment. This review provides an overview of the treatment options that exist, their advantages and disadvantages, and hopefully provides proper guidelines for the current management of this challenging disease.

Combined Modality Therapy↗

Neck disease and distant metastases.

While the implementation of multi-modality neoadjuvant therapy for the treatment of head and neck cancer has resulted in an improvement in local regional control, there has been a resultant increase in the reported incidence of distant metastasis. This shift in the pattern of patient treatment failure highlights the importance of identifying patients at high risk of developing metastasis, accurately detecting metastasis, and improving treatment strategies for advanced disease. Currently, metastatic lesions from head and neck primaries portend a poor prognosis; however, molecular biologic techniques offer a promising approach to the diagnosis and treatment of micrometastasis and distant metastatic lesions. The identification of tumor-specific gene mutations and the cell surface antigens may play a key role in the future management of head and neck cancer. The following review outlines just several of the current issues related to the contemporary diagnosis and management of metastatic lesions of the head and neck.

Carcinoma, Squamous Cell↗

Current management of tonsillar cancer.

Traditionally, risk factors for the development of tonsil cancer include the use of alcohol and/or tobacco, however a significant proportion of new cases develop in young patients without these risk factors. Recent investigation suggests that human papilloma virus (HPV) may serve as an etiology in such cases and represent a unique risk factor in a sub-set of patients. Irrespective of the etiology, in the majority of cases early carcinoma of the tonsil can effectively be treated using single modality therapy. While local-regional control and survival are similar following surgery or radiotherapy, primary surgery can be accomplished with minimal functional morbidity while reserving radiation for recurrent disease. In contrast, surgical salvage following external beam radiotherapy can be technically challenging and is often associated with a significant increase in surgical complications and functional morbidity. In contrast to early tonsillar disease, advanced tonsil cancer represents a clinical challenge that requires multimodality therapy. While advanced lesions are often treated with a combination of radiation, chemotherapy, and surgical ablation, management of the neck and distant metastases continues to present a therapeutic dilemma.

Carcinoma↗

Management of cancer of the retromolar trigone.

Treatment of cancer of the retromolar trigone (RMT) is controversial. While early lesions may be managed with single-modality, more advanced lesions may invade the mandible, pterygoid musculature, and the adjacent mucosa of the tonsillar pillar and soft palate, therefore making therapeutic decisions more complicated. Treatment options traditionally include surgical resection, external beam irradiation, and combined modality therapy. The choice of therapy is dependent on the extent of the tumor, nodal metastasis, and the medical status of the patient and comorbid conditions. The following review outlines the current issues relevant to the diagnosis and therapy of patients with RMT malignancy.

Humans↗

Subcutaneous mandibulotomy: a new surgical access for large tumors of the parapharyngeal space.

OBJECTIVES: Surgery for tumors of the parapharyngeal space (PPS) requires adequate exposure to identify and protect vital structures. Transcervical and transcervical-transparotid approaches to the PPS may be enhanced by mandibulotomy. However, midline mandibulotomy traditionally requires lip-splitting and extensive intraoral incisions, often necessitating tracheostomy and nasogastric feeding. We describe a new technique to gain exposure to the PPS while avoiding these consequences. STUDY DESIGN: Case series. METHODS: Five patients with PPS tumors underwent surgery using a new technique, the subcutaneous mandibulotomy approach (SMA). Each case was retrospectively assessed for tumor size, intraoperative access to the PPS, perioperative complications, and length of hospitalization. RESULTS: In this series, the additional exposure achieved by SMA was adequate to safely remove large PPS tumors that could not be delivered through the transcervical-transparotid approach. All patients started oral diets on postoperative day 1 and were discharged within 3 days. There were no intraoperative complications, and postoperative complications were self-limited. The pathologic entities were a venous malformation, a paraganglioma, and three large, deep-lobe pleomorphic adenomas of the parotid. CONCLUSIONS: We introduce a new technique, the SMA, which affords excellent access to the PPS without the lip-split, chin-split, and floor of mouth incisions. The SMA avoids both nasogastric feeding and a tracheostomy and offers improved cosmesis compared with a traditional midline mandibulotomy. Our current stepwise approach to achieve exposure to the PPS includes use of the SMA as an intermediate step for extensive PPS lesions, which are inaccessible through the transcervical approach yet do not require full labiomandibulotomy for safe and complete removal.

Adenoma, Pleomorphic↗

The kinetics and pattern of tracheal allograft re-epithelialization.

Extensive tracheal defects may pose a life-threatening dilemma. Although tracheal transplantation may represent a reconstructive solution, very little is known regarding the immunobiology and behavior of tracheal allografts. The objective of this study was to assess the pattern and kinetics of re-epithelialization of orthotopic tracheal allografts in immunosuppressed recipients. Thirty-eight age-matched mice were randomly assigned to five experimental groups. BALB/c donor tracheal segments were orthotopically transplanted into either syngeneic BALB/c or MHC mismatched allogeneic C57BL/6 recipients with and without immunosuppression. On post-transplant days 7, 14, 28, 48, and 62, animals from each group were evaluated by serial histology, electron microscopy, and serial immunohistochemical analysis for mucosal phenotype, re-epithelialization pattern, and lymphocyte subpopulations. Nonimmunosuppressed recipients underwent recipient-derived basal cell re-epithelialization by Day 48, with differentiation into a sparse population of ciliated columnar epithelium by Day 62, whereas immunosuppressed recipients underwent basal cell re-epithelialization 28 d after transplantation and differentiation into a dense population of ciliated columnar epithelium by Day 48. The re-epithelialization process occurred in a definable pattern that was significantly enhanced with the addition of immunosuppression. Orthotopic tracheal transplants undergo progressive re-epithelialization with recipient-derived basal cells that differentiate into ciliated columnar epithelium in a definable pattern that is enhanced with the addition of immunosuppression.

Animals↗

Microvascular transplantation of tracheal allografts model in the canine.

The inability to reconstruct extensive and often life-threatening tracheal defects is a clinical dilemma. The objective of this study was to achieve microvascular revascularization and transplantation of long-segment circumferential tracheal allografts in a canine model. Fifteen mongrel dogs were randomly assigned to 5 treatment groups. Twelve dogs underwent an excision of an 8-cm tracheal segment followed by transplantation and microvascular revascularization of an 8-cm cervical trachea allograft. Group 1 (n = 4) was treated with 10 mg/kg per day of cyclosporin A (CsA) and 7.5 mg/kg per day of mycophenolate mofetil (MM). Group 2 (n = 4) was treated with 5 mg/kg per day of CsA and 7.5 mg/kg per day of MM. Group 3 (n = 4) was treated with 2.5 mg/kg per day of CsA and 7.5 mg/kg per day of MM. Group 4 (n = 2) underwent an autograft tracheal transplant and received postoperative 2.5 mg/kg perday of CsA and 7.5 mg/kg per day of MM. Group 5 (n = 1) did not undergo surgery, but received postoperative 2.5 mg/kg per day of CsA and 7.5 mg/kg per day of MM. The animals were maintained for a duration of 30 days, during which time the graft was assessed by routine endoscopic examination and tracheal biopsies. Ex vivo, tracheal autografts were examined grossly for graft healing and microscopically for histologic architecture. The mean survival times were 13.25 days (group 1), 16 days (group 2), and 20 days (group 3). There was 1 early allograft failure secondary to microvascular thrombosis, and there were 4 delayed failures secondary to postoperative wound infections. Five dogs were euthanized before the end of the 30-day observation period because of failure to thrive or hypocalcemic tetany. None of the dogs in the study demonstrated endoscopic or histologic evidence of rejection before euthanasia. Postmortem examination of the surviving dogs demonstrated normal histologic architecture without evidence of rejection. For the first time, we have achieved allotransplantation of long tracheal segments based on the cranial thyroid artery and internal jugular vein. Minimal systemic immunosuppression appears to be associated with a higher survival rate and a lower complication rate.

Animals↗

Laryngeal and tracheal transplantation: ethical limitations.

Over the last decade, there have been extraordinary developments in the field of transplantation science. As a result, organ transplantation enjoys a success that is unparalleled since its introduction nearly 50 years ago. Progress in the laboratory has translated into less toxic, more effective immunosuppressive therapies that have improved both allograft survival and patient quality of life. Consequently, physicians and their patients look toward a new frontier, the transplantation of non-vital organs. While the transplantation of non-vital organs is technically feasible, as demonstrated by the recent success of a human laryngeal transplant, a variety of ethical concerns must be confronted before tracheal and laryngeal transplantation can be offered to patients as a reconstructive option. When considering the risks and benefits of non-vital organ transplantation, one must consider the immeasurable impact of a procedure on the patient s quality of life. The focus of this article is on quality of life and the role of laryngotracheal transplantation in contemporary medicine.

Animals↗