Biomedical subjects

Douglas B Chepeha

Publications and source records attributed to Douglas B Chepeha.

At least 19 recordsLinked to original sources

PubMed2007

Acceleration of hyperfractionated chemoradiation regimen for advanced head and neck cancer.

BACKGROUND: Our aim was to evaluate the acceleration of a hyperfractionated, concurrent chemoradiation regimen (HxCRT) for advanced head and neck squamous cell carcinoma (HNSCC). METHODS: Patients with unresectable HNSCC were treated based on a previously published HxCRT regimen: 1.25 Gy twice daily to 70 Gy concurrent with cisplatin 12 mg/m(2)/day and 5-fluorouracil 600 mg/m(2)/day for 5 days, weeks 1, 5. This regimen was accelerated in this series by shortening the treatment from 7 to 6 weeks by omitting the planned mid-treatment 1-week break. RESULTS: Forty-six patients with T3-4/N3 disease were treated. The main acute toxicity was pharyngeal. Median weight change during therapy in patients with and without enteral feeding tubes was -3.8% and -7.9%, respectively (p = .08). Fifteen percent had late grade III pharyngeal toxicity. Local/regional and distant failure rates were 28% and 17%, respectively; 52% are alive without evidence of disease. CONCLUSIONS: In nonresectable HNSCC, acceleration of the HxCRT regimen is feasible, requiring enteral feeding tubes during therapy in most patients.

Adult↗

PubMed2007

Preoperative MR angiography in free fibula flap transfer for head and neck cancer: clinical application and influence on surgical decision making.

OBJECTIVE: We review the fibular free flap surgical procedure to illustrate the usefulness of preoperative lower limb MR angiography and to show how calf vascular anatomy on MR angiography affects patient surgical management. CONCLUSION: With its high positive predictive value and sensitivity, preoperative MR angiography can improve the chances of a successful outcome at the recipient mandibular site. It provides the reconstructive surgeon with a road map, revealing vascular anomalies or disease that could alter or contraindicate surgery.

Adult↗

PubMed2005

Predictive factors of local-regional recurrences following parotid sparing intensity modulated or 3D conformal radiotherapy for head and neck cancer.

BACKGROUND AND PURPOSE: Predictive factors for local-regional (LR) failures after parotid-sparing, Intensity modulated (IMRT) or 3D conformal radiotherapy for head and neck (HN) cancers were assessed. PATIENTS AND METHODS: One hundred and fifty-eight patients with mostly stages III-IV HN squamous cell carcinoma underwent curative bilateral neck irradiation aimed at sparing the parotid glands. Patient, tumor, and treatment factors were analyzed as predictive factors for LR failure. RESULTS: Twenty-three patients had LR recurrence (19 in-field and four marginal). No differences were found in the doses delivered to the PTVs of patients with or without in-field recurrences. In univariate analysis, tumor site was highly predictive for LR failure in both postoperative and definitive RT patients. In postoperative RT patients, pathologic tumor size, margin status, extracapsular extension (ECE) and number of lymph node metastases, were also significantly predictive. Multivariate analysis showed tumor site (oropharynx vs. other sites) to be a significant predictor in all patients, and involved margins and number of involved lymph nodes in postoperative patients. CONCLUSIONS: Clinical rather than dosimetric factors predicted for LR failures in this series, and were similar to those reported following standard RT. These factors may aid in the selection of patients for studies of treatment intensification using IMRT.

Adult↗

PubMed2005

Metabolic abnormalities associated with weight loss during chemoirradiation of head-and-neck cancer.

PURPOSE: Weight loss caused by acute mucositis and dysphagia is common during concurrent chemoirradiation (chemo-RT) of head-and-neck (HN) cancer. The metabolic consequences of weight loss during chemo-RT were investigated. PATIENTS AND METHODS: Ninety-six patients with locally advanced HN cancer were treated from 1995 to 2001 on protocols that consisted of 1 to 2 cycles of induction cisplatin/5-fluorouracil followed by irradiation (70 Gy over 7 weeks) concurrent with cisplatin (100 mg/m2 every 3 weeks). Body weights and metabolic evaluations were obtained before and during induction chemotherapy and chemo-RT. Greatest percent changes in weight and in the laboratory values were calculated for each phase of therapy. RESULTS: During induction chemotherapy, significant changes were found in BUN, BUN:creatinine ratio, HCO3, Mg, and albumin, but not in creatinine, Na, K, or weight. During chemo-RT, significant additional changes were observed in all parameters measured, including increases in BUN, creatinine, BUN: creatinine ratio, and HCO3 and decreases in Mg, albumin, Na, K, and weight. The magnitude of most of these changes was significantly greater during chemo-RT than during induction chemotherapy. During chemo-RT, 35% of the patients had more than 10% body weight loss and 6 patients had an increase in creatinine of more than 100%, including 5 patients with Grade 2 nephrotoxicity, all of whom had weight loss 10% or more. Significant correlations were found between weight loss and creatinine (p < 0.0001) or BUN (p = 0.0002) rises, but not with BUN:creatinine ratio or other metabolic changes. Age, gender, tobacco history, hypertension, and diabetes mellitus were not significant predictors of nephrotoxicity. CONCLUSIONS: Weight loss during cisplatin-containing chemo-RT was found to be associated with reduced kidney function. These findings do not establish cause-effect relationships; however, they highlight the importance of intensive supportive measures of nutrition and hydration beyond standard hydration during cisplatin administration. These intensive measures should be enacted before a 10% weight loss is reached.

Analysis of Variance↗

PubMed2005

Voice and swallowing outcomes of an organ-preservation trial for advanced laryngeal cancer.

INTRODUCTION: Organ-preservation treatment approaches for advanced laryngeal cancer patients that use combination chemoradiotherapy result in cure rates similar to primary laryngectomy with postoperative radiotherapy. In the national VA Larynx Cancer Trial, successful organ preservation was associated with an overall improvement in quality of life but not in subjective speech compared with long-term laryngectomy survivors. As part of a Phase II clinical trial, a prospective study of speech and swallowing results was conducted to determine if larynx preservation is associated with improved voice and swallowing compared with results in patients who require salvage laryngectomy. SUBJECTS: A total of 97 patients with advanced laryngeal cancer (46 Stage III, 51 Stage IV) were given a single course of induction chemotherapy (cisplatin 100 mg/m2 on Day 1 and 5-FU 1,000 mg/m2/day x 5 days), followed by assessment of response. Patients with less than 50% response underwent early salvage laryngectomy, and patients with 50% or better response underwent concurrent chemoradiation (72 Gy and cisplatin 100 mg/m2 on Days 1, 22, and 43), followed by two cycles of adjuvant chemotherapy (DDP/5-FU). Direct laryngoscopy and biopsy were performed 8 weeks after radiation therapy to determine final tumor response. Late salvage surgery was performed on patients with persistent or recurrent disease. METHODS: Completed survey data on voice and swallowing utilizing the Voice-Related Quality of Life Measure (V-RQOL) and the List Performance Status Scale for Head and Neck Cancer Patients (PSS-HN) were obtained from 56 patients who were alive and free of disease at the time of survey, with a minimum follow-up of 8 months. Comparisons were made between patients with an intact larynx (n = 37) vs. laryngectomy (n = 19), as well as early (n = 12) vs. late salvage laryngectomy (n = 7). Multivariate analysis was performed to determine factors predictive of voice and swallowing outcomes. Overall 3-year determinant survival was 87%, with median follow-up of 40 months. RESULTS: Patients with an intact larynx demonstrated significantly higher (p = 0.02) mean V-RQOL scores (80.3) than did laryngectomy patients (65.4). This finding was consistent in the social-emotional (p = 0.007) and physical functioning domains (p = 0.03). No differences in V-RQOL scores were found in comparisons between early and late salvage laryngectomy. Multiple linear regression revealed that predictors of higher total V-RQOL scores include lower T stage (p = 0.03), organ preservation (p = 0.0007), and longer duration since treatment (p = 0.01). Understandability of speech was better in patients with an intact larynx (p = 0.001). Overall swallowing function was comparable between groups. Multiple logistic regression revealed that longer duration since treatment (p = 0.03, odds ratio = 1.1) and lower maximal mucositis grade (p = 0.03, odds ratio = 0.3) were predictive of higher likelihood of eating in public. Nutritional mode consisting of oral intake alone without nutritional supplements was achieved in 88.9% of patients with an intact larynx compared with 64.3% of laryngectomees (p = 0.09). CONCLUSIONS: Voice-related quality of life is better in patients after chemoradiation therapy compared with salvage laryngectomy. Earlier salvage, although known to be associated with fewer surgical complications, did not result in improved voice; however, the number of patients analyzed is small. Overall swallowing function is good in all patients; however, patients with an intact larynx are more likely to obtain nutrition with oral intake alone without supplements. Such measures of function and quality of life are important endpoints to help judge overall effectiveness as newer, more aggressive treatment protocols with added toxicities are developed and evaluated.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Osseocutaneous radial forearm free tissue transfer for repair of complex midfacial defects.

OBJECTIVE: To evaluate the resulting aesthetics, function, and donor site morbidity of the osseocutaneous radial forearm free flap (OCRFFF) used for midface reconstruction. DESIGN: Prospective case series and a retrospective review of results. PATIENTS: Ten patients from an academic practice who underwent reconstruction at the University of Michigan Hospitals between 1995 and 2001. INTERVENTIONS: All patients had maxillectomy defects in which the entire infraorbital rim was reconstructed with an OCRFFF. Of the 10 patients included in the study, 3 underwent a total maxillectomy with orbital exenteration, 4 had a total maxillectomy without orbital exenteration, and 3 had a limited maxillectomy that did not involve the palate. Patients with palatal defects underwent reconstruction with a prosthetic palatal obturator. MAIN OUTCOME MEASURES: Facial contour and aesthetic results, speech understandability, ability to eat solid foods, oronasal separation, socializing outside the home, and return-to-work status. Flap success, donor site morbidity, and orbital complications were also studied. RESULTS: Mean +/- SEM follow-up was 23.2 +/- 5.0 months. A modified Funk facial deformity scale was used, and 7 of the 10 patients had either no deformity or minimal deformity. The mean aesthetic score for these reconstructions was 2.1 +/- 0.3 on a scale of 1 to 4, with 1 representing no deformity and 4 representing a severe deformity. All patients returned to a solid diet and had understandable speech, although patients who had an orbital exenteration trended to poorer scores. All patients socialized either frequently or occasionally outside the home, and all patients not retired or disabled prior to surgery returned to work. CONCLUSION: The OCRFFF reconstruction of the infraorbital rim in patients with total maxillectomy defects and obturator of the palatal defect controls orbital complications and optimizes aesthetic outcome while achieving nearly normal palatal function.

Adult↗

PubMed2005

Spinal epidural abscess after cervical pharyngoesophageal dilation.

BACKGROUND: Esophageal perforation is an uncommon but known complication of esophageal dilation. Abscess after esophageal tear is rare, especially in the spinal epidural space. This is one case report of such an abscess. METHODS: We present a case of a spinal epidural abscess after cervical pharyngoesophageal dilation. RESULTS: After surgical decompression and abscess drainage, long-term intravenous antibiotics, and physical therapy, the patient has regained some functional use of her left upper extremity. CONCLUSIONS: Early diagnosis with a gadolinium-enhanced MRI and aggressive surgical treatment are keys to successful management with a good functional outcome after this unfortunate complication.

Catheterization↗

PubMed2005

Crosstalk between tumor and endothelial cells promotes tumor angiogenesis by MAPK activation of Notch signaling.

While significant progress has been made in understanding the induction of tumor vasculature by secreted angiogenic factors, little is known regarding contact-dependent signals that promote tumor angiogenesis. Here, we report that the Notch ligand Jagged1 induced by growth factors via mitogen-activating protein kinase (MAPK) in head and neck squamous cell carcinoma (HNSCC) cells triggered Notch activation in neighboring endothelial cells (ECs) and promoted capillary-like sprout formation. Jagged1-expressing HNSCC cells significantly enhanced neovascularization and tumor growth in vivo. Moreover, the level of Jagged1 was significantly correlated with tumor blood vessel content and associated with HNSCC development. Our results elucidate a novel mechanism by which the direct interplay between tumor cells and ECs promotes angiogenesis through MAPK and Notch signaling pathways.

Animals↗

PubMed2004

Prognostic factors in oral cavity and oropharyngeal squamous cell carcinoma.

BACKGROUND: The survival of patients with head and neck squamous cell carcinoma (HNSCC) remains unaffected despite recent therapeutic advances. To reverse this trend, reliable and clinically applicable markers of tumor aggressiveness must be identified. One such marker may be the tumor-associated macrophage content. The authors hypothesized that tumor-associated macrophages contribute to HNSCC aggressiveness, and the objective of the current study was to prove this hypothesis using mRNA expression analysis and a large cohort of clinical specimens. METHODS: Oligonucleotide microarray analysis was performed on a prospective cohort of 20 patients with previously untreated oral cavity or oropharynx squamous cell carcinoma (OC/OP SCCA) and on normal oropharyngeal mucosa from 4 patients. After determining whether macrophage chemoattractants were produced by tumors, conditioned media from three HNSCC cell lines were used to quantify macrophage migration in an in vitro assay. A high-density tissue microarray of 102 patients with previously untreated OC/OP SCCA was stained immunohistochemically for CD68 to identify tissue macrophages, and the results were correlated with clinicopathologic data and survival. RESULTS: Monocyte chemoattractant protein 1 was up-regulated significantly in tumors compared with normal mucosa (P=0.0025; fold change=1.89). All University of Michigan SCC tumor cell line conditioned media caused a significant increase in macrophage migration (P <0.05). Tissue microarray data revealed that macrophage content of the primary tumor was associated strongly with lymph node metastasis (P <0.0001), extracapsular lymph node spread (P=0.0001), and advanced clinical disease stage (P=0.0002). When it was evaluated along with other clinicopathologic data, the macrophage content was found to be an independent predictor of lymph node metastasis (P <0.0001). CONCLUSIONS: Primary tumor macrophage content is a strong predictor of tumor aggressiveness in HNSCC.

Adult↗

PubMed2004

Recurrences near base of skull after IMRT for head-and-neck cancer: implications for target delineation in high neck and for parotid gland sparing.

PURPOSE: Locoregional (LR) failures near the base of the skull, and their relationships to the targets in the high neck, were examined in a series of patients who underwent intensity-modulated radiotherapy (IMRT) for head-and-neck cancer. METHODS AND MATERIALS: Between 1994 and 2002, 133 patients with non-nasopharyngeal head-and-neck squamous cell carcinoma completed a course of curative, parotid-sparing RT. Treatment was delivered until 1996 with conformal three-dimensional techniques and thereafter with multisegmental static IMRT. Of the 133 patients, 80 had oropharyngeal, 27 oral cavity, 12 hypopharyngeal, 11 laryngeal, and 3 unknown primary cancer. The AJCC stage was I in 1, II in 6, III in 26, IVA in 83, and IVB in 12; cancer was recurrent in 5. Sixty patients received primary and 73 postoperative IMRT. 86% of patients (n = 115) had ipsilateral neck metastasis. In all patients, the contralateral neck was clinically node negative but was judged to be at high risk of subclinical disease. Delineation of the superior-most extent of the nodal targets was consistent and corresponded with Rouviere's observations. In the contralateral clinically node-negative neck, the uppermost Level II nodal target was the subdigastric (SD) nodes. To ensure coverage, the uppermost clinical target volume was delineated at the axial CT image in which the posterior belly of the digastric muscle crossed the jugular vein. In the ipsilateral neck, which was node positive in most patients, the uppermost Level II clinical target volume was delineated through the base of the skull. The uppermost retropharyngeal (RP) nodal target was delineated at the level of the top of the C1 vertebral body, accommodating Rouviere's description of the location of the lateral RP nodes. The dose prescription was 70 Gy for the primary planning target volumes (PTVs); 64 Gy and 60 Gy for PTV of the postoperative beds with and without extracapsular extension, respectively; and 50-54 Gy for PTVs of nonoperated subclinical disease, at 1.8-2.0 Gy fractions. In-field or marginal recurrences were defined as those occurring when >95% or 20-95% of the recurrence volume, respectively, had received >95% of the prescribed dose. RESULTS: At a median follow-up of 32 months (range, 6-107 months), 21 patients (16%) had locoregional recurrence. Seventeen recurrences were in-field and four were marginal. The most prevalent nodal recurrence was in Level II bilaterally, where all failures were in-field. In-field failures were observed in the ipsilateral high neck cranial to the SD nodes (all in initially node-positive neck). No recurrences occurred in the contralateral high neck, cranial to the SD nodes, which was not included in the targets. The 95% confidence interval for the risk of recurrence in that region was 0-2.7%. Three RP nodal failures were observed; two were marginal, occurring ipsilateral and contralateral to the primary tumors, and centered cranial to the top of C1. After these recurrences, the RP nodal clinical target volumes were delineated bilaterally through the base of skull, without subsequent RP recurrence. These target delineation guidelines allowed the achievement of a mean contralateral parotid dose of < or =26 Gy (found previously to preserve salivary output significantly) in 82% of the patients. The 3-year actuarial LR recurrence-free survival rate of primary and postoperative IMRT patients was similar (81% and 84%, respectively). Oropharyngeal cancer patients had the greatest LR recurrence-free survival rate (94%, p <0.001). No statistically significant differences were found in the dose delivered to the PTVs or the in-field recurrence volume between patients who had or did not have LR failure. CONCLUSION: These results suggest that when the contralateral node-negative side of the neck has a high risk of subclinical metastasis, it is adequate to include the SD nodes as the cranial-most Level II nodal target in non-nasopharyngeal head-and-neck cancer. In the node-positive side of the neck, this nodal level should be delineated more cranially. The RP nodal targets should be delineated more cranially. The RP nodal targets should be delineated bilaterally and should extend to the base of the skull, rather than to the top of C1. These guidelines allowed substantial sparing of the contralateral parotid gland. The results of this series validate a consensus for target delineation adopted recently by cooperative radiotherapy groups.

Adult↗

PubMed2004

Pectoralis major myocutaneous flap vs revascularized free tissue transfer: complications, gastrostomy tube dependence, and hospitalization.

OBJECTIVE: To evaluate the factors related to surgical complications, rate of gastrostomy tube (G-tube) dependence, and hospitalization in patients undergoing reconstruction with a pectoralis myocutaneous flap vs a soft-tissue revascularized flap. DESIGN: Quasi-experimental case series with a historic control group. POPULATION: A total of 179 patients (138 men and 41 women) with a mean (SD) age of 58 (14) years treated between January 1, 1986, and December 31, 1995, with a pectoralis flap (108 patients) or a revascularized free flap (71 patients). METHODS: Inclusion criteria were first or second extirpation, reconstruction with soft-tissue flap, or defect including the upper aerodigestive tract. Exclusion criteria were secondary reconstruction, or reconstruction for salvage of a complication. RESULTS: Although the major complication rate was not significantly different according to reconstructive approach, hypopharyngeal defects had a significantly higher major complication rate of 30% (6/20) compared with 8% (13/159) for other defect sites (P<.003). The minor complication rate was higher in the pectoralis group, at 57% (62/108), than in the revascularized flap group, at 21% (15/71) (P<.001). G-tube dependence was higher in the pectoralis group at 42% (40/96), in contrast to the revascularized flap group at 16% (10/63) (P<.001). G-tube dependence was 25% higher in patients who underwent salvage surgery after radiation (42% [30/72]) than in patients treated with postoperative radiation (17% [12/69]) (P<.004). Revascularized flaps helped ameliorate the effects of radiation before surgery; 56% (23/41) of the patients who received pectoralis flaps were G-tube dependent, while the rate of G-tube dependence in the revascularized flap group was 23% (7/31) (P<.004). Hospitalization was longer in the pectoralis group (14 days) than the revascularized flap group (12 days) (P<.006). CONCLUSION: Patients who undergo reconstruction with a pectoralis flap have significantly higher minor complication rates, a higher rate of G-tube dependence, and longer hospitalization than patients who undergo reconstruction with a soft-tissue revascularized flap.

Female↗

PubMed2004

Molecular profiling and the identification of genes associated with metastatic oral cavity/pharynx squamous cell carcinoma.

OBJECTIVE: To investigate differences in gene expression profiles between oral cavity/oropharynx squamous cell carcinoma (OC/OP SCC) primary tumors that have metastasized to cervical lymph nodes and nonmetastatic OC/OP SCC tumors. DESIGN: Oligonucleotide microarray analysis of primary tumors was used to produce gene expression profiles. Profile comparisons between metastatic and nonmetastatic tumors were performed using principal component analysis, t test, and fold change differences. A similar comparison between metastatic tumors and noncancer oral mucosa samples was performed to ensure tumor origin. SUBJECTS: A prospective cohort of 20 patients with previously untreated OC/OP SCC who underwent pathologic staging following surgical resection and lymphadenectomy. RESULTS: Of the approximately 9600 genes profiled, 101 demonstrated significant expression differences between the metastatic and nonmetastatic tumors (fold change > or =1.5; P<.01). Among this subset, 57 genes also exhibited significant differences between metastatic tumors and normal mucosa samples (fold change > or =1.5; P<.05). This profile included genes related to the extracellular matrix, adhesion, motility, inflammation, and protease inhibition. Collagen type 11 alpha-1 (COL11A1) demonstrated the greatest differential expression between metastatic and nonmetastatic OC/OP SCC tumors (fold change=7.61; P=.002). Tissue inhibitor of metalloproteinase 1 (TIMP-1) also demonstrated increased expression in metastatic tumors (fold change=3.3; P=.003). CONCLUSIONS: Metastatic OC/OP SCC has a distinct gene expression profile compared with nonmetastatic OC/OP SCC and normal oral mucosa. This metastatic profile includes genes related to the extracellular matrix, adhesion, motility, and protease inhibition. Knowledge gained through tumor gene expression profiling may facilitate early detection of aggressive tumors and targeted therapeutic interventions.

Carcinoma, Squamous Cell↗

PubMed2004

Clinical predictors of quality of life in patients with head and neck cancer.

OBJECTIVE: To identify clinical predictors of quality of life (QoL) in a head and neck cancer patient population. DESIGN, PATIENTS, AND SETTING: A convenience sample of 570 patients with upper aerodigestive tract cancers were surveyed at a tertiary care oncology clinic and Veterans Affairs otolaryngology clinic. INTERVENTIONS: A self-administered health survey was constructed to collect demographic, health, smoking, alcohol, depression symptom, and QoL information. Tumor site and tumor stage, clinical, and treatment data were abstracted from the patient medical records. MAIN OUTCOME MEASURES: Quality of life was assessed using the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36) and the Head and Neck QoL (HNQoL) instrument. RESULTS: Of the 570 eligible respondents, the presence of a feeding tube had the most negative impact on QoL, with significant decrements in 6 of the 8 SF-36 scales and all 4 HNQoL scales (P<.01). In descending order of severity, medical comorbid conditions, presence of a tracheotomy tube, chemotherapy, and neck dissection were also associated with significant (P<.05) decrements in QoL domains. Patients who took the survey more than 1 year after diagnosis had improved QoL in 7 of 12 domains. Hospital site, age, education level, sex, race, and marital status were also significant predictors of QoL. CONCLUSION: There are at least 13 demographic and clinical characteristics that are significant predictors of QoL in patients with head and neck cancer, which should be considered when treating patients and conducting QoL studies in the future.

Adult↗

PubMed2004

Disability in patients with head and neck cancer.

BACKGROUND: Patients with head and neck cancer often experience debilitating speech, eating, and respiratory problems as well as the psychological effects of loss of function and change in body image. These patients often become unemployed as a result of their disease process, which adds financial burden to their already stressful lives. Yet the specific factors associated with unemployment have not been systematically studied. METHODS: This multisite study used survey and chart data to determine the predictors of work-related disability. RESULTS: Of the 384 patients who were working prior to their diagnosis of head and neck cancer, 52% (n = 201) were disabled by their cancer treatment. Multivariate analysis demonstrated significant links between disability and chemotherapy (odds ratio [OR], 3.4; P <.001), neck dissection status (OR, 2.3; P =.01), pain scores (OR, 1.2; P =.01), and time since diagnosis (OR, 0.9; P =.04). CONCLUSIONS: More than half of the patients in this study were disabled by their head and neck cancer or treatment. Patients with head and neck cancer who have undergone chemotherapy or neck dissection or have high pain scores are at increased risk for disability from their cancer or their treatment. Efforts to prevent (if possible), better assess, and treat pain and other adverse effects of head and neck cancer treatments may also have the potential to reduce patient disability.

Disability Evaluation↗

PubMed2004

Length-tension relationship of the feline thyroarytenoid muscle.

Vocal fold tension during phonation is generated by coordinated contraction of the intrinsic laryngeal muscles. The thyroarytenoid muscle has been found to have increased stiffness at various levels of strain when compared with other intrinsic laryngeal muscles. The objective here is to test the hypothesis that the thyroarytenoid muscle exhibits high passive tension during maximal isometric tetanic force generation, and to test the hypothesis that the thyroarytenoid maintains the ability to generate contractile force at high levels of strain more effectively than other skeletal muscle. The thyroarytenoid muscles (n=9) and digastric muscle strips (n=7) were removed from adult random-bred cats. Maximal isometric tension and passive tension at optimum length were measured from each muscle in vitro. Active and passive length-tension curves were constructed for each muscle. The contractile properties of the thyroarytenoid group were compared with those of the digastric muscle group. The thyroarytenoid muscle group required on average 140 mN of passive tension to generate maximal isometric tetanic tension. This represented 39% of the average maximal isometric tetanic tension generated by the muscles. These results were significantly higher than the digastric muscle group, which required on average 28 mN of passive tension (9% of maximal isometric tetanic tension, p<0.05). At 110% of optimum length, the thyroarytenoid muscle maintained 89.8% of maximal isometric tetanic force, whereas the digastric muscle group maintained 67.7% of maximal isometric tetanic force (p<0.05). The thyroarytenoid muscle exhibits higher passive tension when generating maximal isometric tension than the digastric muscle control group. The thyroarytenoid muscle maintains higher levels of active tension at high strain than the digastric muscle control group. We conclude that these findings are related to the ability of the thyroarytenoid muscle to function as a fine tensor of the vocal fold in a high strain environment.

Animals↗

PubMed2004

Radial forearm free tissue transfer reduces complications in salvage skull base surgery.

OBJECTIVE: Patients who undergo skull base resection after prior surgery or radiation may be at high risk for complications when local flaps alone are used for reconstruction. To determine whether the complication rate could be reduced, fasciocutaneous free tissue transfer was used to reinforce the dural closure in patients who had prior skull base surgery or radiation. METHODS: This study is a case series of 20 patients (14 males, 6 females, aged 8-79 years of age with a mean of 47.7 years) from 1997 to 2001 who had prior skull base surgery or radiation, and underwent salvage skull base resection without large volume defects. All patients had a radial forearm free tissue transfer to reinforce the dural closure. Six patients had an osseous component to the forearm flap to provide vascularized bone to the orbital rim. RESULTS: The overall local complication rate was 35%. Three patients (15%) had major complications including 1 case of meningitis, 1 case of cerebrospinal fluid leak, and 1 case of a flap requiring venous salvage. There were no flap failures, 1 idiopathic median nerve palsy, and no pathologic radius bone fractures. CONCLUSION: Reconstruction with fasciocutaneous free tissue transfer for high-risk patients with low-volume dural defects following skull base resection can minimize the risk of major postoperative complications. EBM RATING: C.

Adolescent↗

PubMed2004

Restoration of the orbital aesthetic subunit in complex midface defects.

OBJECTIVES/HYPOTHESIS: Although various options exist for restoration of the orbital defect in complex craniofacial resections, the aesthetic appearance and functional result of the orbit are optimized when the bony orbital architecture, orbital volume, and facial contour are specifically addressed. The study describes an approach using free tissue transfer for restoration of the native orbital aesthetic subunit. STUDY DESIGN: Retrospective case series. METHODS: Nineteen patients (male-to-female ratio, 14:5; mean age, 52 y [age range, 8-79 y]) in the study period between 1997 and 2001 had orbital defects that could be classified into one of the following categories: 1) orbital exenteration cavities only, 2) orbital exenteration cavities with resection of less than 30% of the bony orbital rim, or 3) radical orbital exenteration cavities with resection of overlying skin and bony malar eminence. Group 1 had reconstructions with fasciocutaneous forearm flaps; group 2, with osseocutaneous forearm flaps; and group 3, with osseocutaneous scapula flaps. RESULTS: Eighteen of 19 patients achieved a closed orbital reconstruction with restoration of the orbital aesthetic subunit. Among 16 patients with more than 4 months of follow-up, 10 patients had minimal or no resulting facial contour deformity and 8 patients engaged in social activities outside the home on a frequent basis. Five of the nine patients who were working before their surgery were able to return to work. CONCLUSION: Patients with complex midface defects involving the orbit can undergo free tissue transfer and have successful restoration of the native orbital aesthetic subunit without an orbital prosthesis.

Adolescent↗

PubMed2004

Contemporary skull base reconstruction.

PURPOSE OF REVIEW: Tumors of the skull base that would have been considered inoperable thirty or forty years ago are now routinely resected with reliable results due to the advancement of modern reconstructive techniques. High mortality rates were common prior to the use of vascularized tissue for skull base repair. However, the advent of local flap reconstruction for skull base defects in the 1960s revolutionized skull base surgery. The use of regional flaps in the 1970s and 1980s allowed skull base surgeons to perform more extensive surgeries, but complication rates were still quite high. RECENT FINDINGS: Experience with free tissue reconstruction increased through the 1980s and 1990s and has become a reliable method to separate the intracranial from extracranial environments. Free tissue transfer has allowed surgeons to address the large volume defects created by extensive skull base resections and has provided dependable, vascularized tissue that is relatively resistant to adjuvant radiation. Local flaps have also become a powerful reconstructive tool in conjunction with free tissue transfer, and in some select cases, may be sufficient alone for reconstruction. SUMMARY: The prevention of serious complications after skull surgery has improved with the use of vascularized tissue. Depending on the anatomic site, the extent of the defect, and the quality of local tissues, either free tissue transfer and/or local flap reconstruction is preferred. Regional flap reconstruction should be reserved for cases where alternative reconstructive techniques are not available.

Bone Transplantation↗