Biomedical subjects

M L Urken

Publications and source records attributed to M L Urken.

At least 37 records · Page 2Linked to original sources

PubMed1999

Surveillance CT and the prompt use of CT-guided fine-needle aspiration in patients with head and neck cancer who have undergone surgery.

OBJECTIVE: The purpose of this study was to assess the usefulness of prompt CT-guided fine-needle aspiration in the evaluation of suspected tumor recurrence seen on surveillance images of patients who had undergone surgery for head and neck cancer. SUBJECTS AND METHODS: We reviewed 32 patients who had undergone CT-guided fine-needle aspiration after surgery for head and neck cancer. CT-guided fine-needle aspiration was performed with a 22-gauge spinal needle and a cytopathologist was present to assess the adequacy of the biopsy sample. As many as five needle passes were made. RESULTS: Of the 32 cases, pathologic findings revealed squamous cell carcinoma (n = 27), mucoepidermoid carcinoma (n = 2), neuroendocrine carcinoma (n = 1), papillary thyroid carcinoma (n = 1), and adenocarcinoma (n = 1). In 20 cases (62.5%) the results of CT-guided fine-needle aspiration were positive for tumor recurrence, whereas in 11 cases (34.4%) the results were negative. In one case (3.1%) the results were nondiagnostic. Of the 11 patients with negative findings on CT-guided fine-needle aspiration, two patients had a subsequent recurrence that was not at the biopsy site. There were no complications from the procedure. CONCLUSION: When a radiologist who is trained in head and neck imaging identifies with CT a possible early recurrence of tumor, the prompt use of CT-guided fine-needle aspiration is an effective way to diagnose these tumors so that appropriate treatment can be initiated.

Adult↗

PubMed1999

Complications of head and neck surgery in the elderly.

Many recent studies have documented that complications of head and neck surgery are no more common in the elderly than in younger patients. But few studies have addressed complication rates in a population undergoing reconstruction with microvascular free tissue transfer (MFTT). We compared outcomes of patients older and younger than 70 who underwent MFTT and found no significant difference in the incidence of surgical complications. However, older patients did experience more medical morbidity and more surgical mortality. Nonetheless, we conclude that MFTT should not be withheld from patients 70 years and older solely on the basis of their advanced age.

Aged↗

PubMed1999

The back door: venous-mediated metastasis into cervical lymph nodes as an alternative metastatic pathway for oropharyngeal squamous cell carcinoma.

Circulating lymphocytes may home to lymph nodes (LNs) via paracortical postcapillary venules, high-endothelial venules (HEVs) that recognize circulating lymphocytes, enabling them to migrate into nodal cortical/paracortical regions. Our goal was to find any histologic, immunohistochemical, or in vitro evidence to support the hypothesis that squamous cell carcinoma (SCC) may gain access to LNs via an alternative venolymphatic pathway. Slides from 67 neck dissections with SCC were studied. Standard criteria for lymphatic-mediated metastasis were used; criteria for evidence ofvenolymphatic metastasis were tumor nests localized to the paracortical regions, directly contiguous to HEVs but not marginal sinuses. Cases in which LN architecture was obliterated by metastases were excluded. A modified Stamper-Woodruff assay, which assesses HEV binding, incubated cell lines from oral carcinomas and lung adenocarcinomas with fresh frozen LN sections. Double-blinded cell counts were performed by two observers and analyzed by Student's t test. Immunohistochemical examination was undertaken on 19 paraffin-embedded cases with the monoclonal antibody, MoAb CD44v6, to discover whether expression of this adhesion molecule correlated with metastatic pattern. Twenty-nine cases (66%) revealed evidence only for the LN route of metastasis; 4 cases (9%) were classified as venolymphatic metastasis; 11 cases (25%) showed evidence for both pathways. The Stamper-Woodruff assay confirmed that SCC cells preferentially bound to HEV within cervical LN sections more than did adenocarcinoma cells (P = .02). Strong staining to MoAb CD44v6 was seen in 18 (95%) of 19 SCCs with a membranous pattern. Occasionally, CD44v6 highlighted tumor emboli adjacent to HEVs, but no overall correlation could be made between CD44v6 expression and pattern of spread. Tumor metastasis via lymphatic channels is the predominant mode of metastatic spread, but the venolymphatic route is a plausible alternative pathway. The preferential attachment of SCC cells to HEVs supports this theory.

Cell Adhesion↗

PubMed1998

Oromandibular reconstruction using microvascular composite flaps: report of 210 cases.

OBJECTIVE: To review the experience of 1 microvascular surgeon during an 11-year period in performing 210 vascularized bone-containing free flaps for oromandibular reconstruction. DESIGN: Retrospective medical records review of patients who underwent primary and secondary oromandibular reconstruction with the use of vascularized bone free flaps. SETTING: Academic medical center. PATIENTS: A total of 201 patients underwent 210 composite free-flap reconstructions of the mandible for various disorders and with a range of bony and soft tissue defects. INTERVENTION: All patients underwent the microvascular transfer of vascularized bone flaps from the ilium, fibula, or scapula. In selected cases, 2 simultaneous free flaps were transferred to achieve an optimal bone and soft tissue reconstruction. Endosteal dental implants were used in 81 patients, with a total of 360 fixtures placed during these 11 years. MAIN OUTCOME MEASURES: The success of microvascular free tissue transfer, dental implant extrusion, and short- and long-term complications at the recipient and donor sites. RESULTS: Of the 210 mandibular reconstructions that were performed, 202 were successful in reestablishing mandibular continuity. Reexploration for vascular-related complications was done in 16 patients, 8 of whom were successfully treated, yielding an overall success rate of 96%. The overall success rate for endosteal dental implants was 92%. The implant success rate was 86% when the bone in which the fixtures were placed was irradiated postoperatively. The success rate was 64% in the 14 fixtures that were placed into previously irradiated bone. CONCLUSIONS: The success of the use of vascularized bone free flaps in restoring continuity to the mandible is clearly demonstrated in this series. There was an acceptable incidence of donor- and recipient-site complications that resulted in minimal long-term morbidity. The careful selection of a donor site(s) for oromandibular reconstruction allows for an optimal restoration of bony and soft tissue defects. Dental implants can be safely used in oromandibular reconstruction with a high level of success. Placing these implants during the initial surgery shortens the duration for achieving dental rehabilitation and enhances the success of the implants when postoperative radiotherapy is administered.

Adolescent↗

PubMed1998

Complications of microvascular head and neck surgery in the elderly.

OBJECTIVES: To evaluate the complications of head and neck reconstruction using microvascular free tissue transfers (MFTTs) performed in an elderly population and to determine whether these complications are more common than in a younger population. SETTING: Tertiary referral center. PATIENTS AND DESIGN: Retrospective, consecutive chart review of patients older than 70 years who underwent MFTT in the past 5 years (group 1). The complications in this population were compared with those in a second group (group 2) of consecutive patients younger than 70 years who were matched according to the site of the primary tumor. MAIN OUTCOME MEASURES: Surgical and medical complications. RESULTS: The median age for group 1 was 74 years and for group 2, 55 years. The overall complication rate for group 1 was 48%, compared with 57% for group 2. In group 1, surgical morbidity was less common and medical morbidity was more common than in group 2. Mortality rate was 6% for group 1 and 0% for group 2. The types of complications were similar for both groups. There was no difference in complication rates when complications were classified by site of the defect, patient status determined by American Society of Anesthesiologists classification, or use of preoperative radiation. The overall success rate of MFTT was 100% for group 1 and 94% for group 2. CONCLUSIONS: Microvascular free tissue transfers for head and neck reconstruction can be safely performed in the elderly. An age older than 70 years does not increase the rate of surgical complications following head and neck reconstruction with MFTT. Medical complications, however, are more common and are equally divided between bronchopulmonary and cardiovascular effects.

Aged↗

PubMed1998

Characterizing the antigenic profile of the human trachea: implications for tracheal transplantation.

BACKGROUND: Tracheal transplantation may be a viable alternative in select situations of long-segment tracheal stenosis. Issues concerning human tracheal antigenicity and the requirement for systemic immunosuppression need to be addressed. This study examined the distribution of the major transplantation antigens on fresh human trachea. METHODS: Frozen sections of 10 human tracheas were examined for class I (HLA [human leukocyte antigen]-A, -B, -C) and class II (HLA-DR) histocompatibility antigens using mouse monoclonal antibodies in an indirect immunoperoxidase assay. The tracheal mucosa, perichondrium, cartilage matrix, and chondrocytes were examined and assigned a semiquantitative score for HLA class I and class II expression. RESULTS: The tracheal mucosa was strongly antigenic for HLA class I and class II antigens, whereas the perichondrium contained only scattered fibroblasts that were positive for both classes. The polysaccharide matrix was consistently devoid of class I or class II expression. The chondrocytes of all 10 specimens expressed diffuse class I positivity; only two specimens contained chondrocytes that expressed class II positivity. CONCLUSIONS: The human trachea contains "compartments" of highly antigenic tissue that are morphologically distinct from regions of lesser antigenicity.

Biopsy↗

PubMed1998

Effect of time on the viability of ischemic skin flaps treated with vascular endothelial growth factor (VEGF) cDNA.

This study examined the efficacy of gene therapy on wound healing. The authors investigated whether delivery of the gene encoding a particular cytokine, known to be important in angiogenesis, could affect ischemic skin flaps. Anterior abdominal skin flaps, based solely on the epigastric artery and vein, were created in the Sprague-Dawley rat model. At the time of elevation, the arterial pedicle supplying each flap was infused either with the gene for vascular endothelial growth factor (VEGF) or physiologic saline alone. The flaps were resutured into place and observed for a period of either 4 or 3 days, at which time the pedicle was ligated. Twenty minutes following ligation, blood flow in the flaps was measured by dye fluorescence. Tissue viability of the flaps was subsequently measured by planimetry after a period of 7 days. Flaps that received the VEGF gene and were ligated at 4 days had an average dye fluorescence index (DFI) of 31.1 following ligation, and 93.9 percent viable tissue after 7 days. Flaps that received saline alone, and were ligated following a similar interval, had an average DFI of 14.0 and 31.9 percent viable tissue. Among the subjects that were ligated at 3 days, only a single, gene-infused flap had any noticeable viable tissue after 7 days. The DFI of these groups was 11.0 for the gene-infused group and 22.1 for the saline-infused group. The results suggest that delivery of the gene for VEGF can improve the survival of ischemic skin flaps, but that the effect of gene therapy is not limitless.

Analysis of Variance↗

PubMed1998

Tracheal transplantation: superior and inferior thyroid artery perfusion territory.

OBJECTIVE: To determine the perfusion territories of the superior and inferior thyroid arteries in humans. Tracheal transplantation is a potential option for management of long-segment tracheal stenosis. However, the maximum length of vascularized trachea that can be reliably transplanted has not been established. STUDY DESIGN: The tracheal vascular territory of individual superior and inferior thyroid arteries was determined separately in 10 humans postmortem. METHODS: India ink was infused unilaterally under controlled pressure into the superior (n = 5) and inferior (n = 5) thyroid arteries of cadaveric tracheas. Tracheas were sectioned longitudinally and the caudalmost extent of mucosal dye staining was determined via microscopic assessment. RESULTS: The tracheal perfusion territory of the superior thyroid artery was two to five rings (1.7 +/- 0.5 cm) and the inferior thyroid artery, nine to 13 rings (6.5 +/- 1.1 cm). In both cases, the tracheal mucosa on the contralateral side was stained to the same caudal level. CONCLUSIONS: The inferior thyroid artery was shown to perfuse the trachea maximally to the 13th ring (8.1 cm). As such, the unilateral inferior thyroid artery would serve as a suitable vascular component for long-segment tracheal transplantation in humans.

Adult↗

PubMed1998

Anatomy and vascular perfusion territories of the superior thyroid artery in Macaca mulatta.

OBJECTIVE: Currently, methods used to repair long segment tracheal stenosis are unreliable. Here, a new nonhuman primate model of tracheal transplantation is used based on its evolutionary proximity to humans. STUDY DESIGN: Prospective dye perfusion study in Macaca mulatta. METHODS: After anatomical characterization, Evan's blue solution was injected into the right superior thyroid artery unilaterally (n = 5). Staining of the tracheal vasculature was then examined. RESULTS: In M mulatta, the superior thyroid artery branched from the lingual-facial trunk and was 0.64 +/- 0.18 mm in diameter. Dye staining was bilateral, with the ipsilateral side extending to 2.98 +/- 0.58 cm and the contralateral to 2.88 +/- 0.88 cm, 12.9 +/- 3.45 rings (47% of trachea). CONCLUSIONS: The tracheal vasculature has extensive bilateral collateral vascular channels that may provide a graft survival advantage. Macaques may serve as a good model of tracheal transplantation because of the collateral vascularization of the trachea and the extensive tracheal segment supplied by the superior thyroid artery, and because the superior thyroid artery and vein are anastomosable.

Anastomosis, Surgical↗

PubMed1998

Locally administered vascular endothelial growth factor cDNA increases survival of ischemic experimental skin flaps.

Microvascular surgery has emerged as an attractive area for recent advances in the field of gene therapy. The present study investigated the survival of ischemic, experimental skin flaps after treatment with the gene encoding vascular endothelial growth factor (VEGF). In 30 Sprague-Dawley rats, anterior abdominal skin flaps supplied by the epigastric artery and vein were created. Ten animals were treated with a mixture of liposomes and the cDNA encoding the 121-amino acid isoform of VEGF. Another 10 animals were treated with control plasmid DNA and liposome transfection medium; a third group of 10 animals was given physiologic saline. Each solution was injected directly into the femoral artery distal to the origin of the epigastric pedicle supplying the flap. Four days after injection, the pedicle was ligated and blood flow in the flap was approximated using dye fluorescence. Seven days later, the amount of viable tissue within the flap was measured by planimetry. After the animals were killed, specimens from both the operated and nonoperated sides of the abdomen were harvested for immunohistologic evidence of VEGF protein expression. Average dye fluorescence indices of the three groups (VEGF cDNA, control plasmid, and saline) 2 hours after pedicle ligation were 35.9, 23.9, and 53.9 percent, respectively (p < 0.05). Compared with the two control groups, flaps receiving VEGF cDNA had significantly greater tissue viability at the end of 7 days: 93.9 versus 28.1 percent for the control plasmid DNA group and 31.9 percent for the saline group (p < 0.05). Immunohistochemical staining documented increased deposition of VEGF protein in flaps that were infused with the VEGF cDNA versus saline alone (p < 0.05). The results indicated that the survival of ischemic tissues can be enhanced by administration of a cDNA encoding VEGF, a protein known to be important in the process of angiogenesis and wound healing.

Animals↗

PubMed1997

Osteogenic sarcoma of the jaw. A clinicopathologic review of 12 patients.

OBJECTIVE: To review our experience with osteogenic sarcoma of the jaw. DATA SOURCE: The pathology and clinical files of the Mount Sinai Medical Center, New York, NY, were examined. STUDY SELECTION: For the past 6 years, 12 pathologically documented cases were identified. DATA EXTRACTION: Surgical resection margins, histological tumor grade and subtype, and treatment modality were reexamined with regard to effect on outcome. DATA SYNTHESIS: The mean age of occurrence was 32.6 years, ranging from 12 to 60 years. Male predominance was noted in both mandibular and maxillary tumors. Local recurrence occurred in 6 of 12 patients after 3 months to 5 years; 4 of these patients have either persistent disease or died of disease. In this recurrence group, only 2 patients remain disease free 7 and 12 years after initial diagnosis and 6.5 and 8 years after recurrence. CONCLUSIONS: This study is too small to draw statistically significant conclusions. However, the longest survivor in the group (disease free at 12 years) had a histologically low-grade mandibular tumor. We reiterate the findings in the literature, which agree that osteogenic sarcoma of the jaw is an aggressive disease. Patient prognosis may depend on the tumor grade and size on presentation, as well as the completeness of initial surgery as monitored by resection margins.

Adult↗

PubMed1997

Sinonasal melanoma. A clinicopathologic study of 25 cases and literature meta-analysis.

OBJECTIVES: To report on 25 cases of sinonasal melanoma at our institution during 1977 to 1995 and to perform a literature meta-analysis on sinonasal melanoma and study survival statistics. DATA SOURCES: A retrospective search of pathology and clinical records at our institution to identify patients with sinonasal melanoma; a retrospective search of the English-language literature for cases of documented sinonasal melanoma. STUDY SELECTION: Cases from our institution were included if there was adequate pathologic material confirming the pathologic diagnosis. For the meta-analysis, cases were accepted if they included convincing histologic illustrations or documentation of melanin by Fontana-Masson staining or ultrastructural examination or had an acceptable immunohistochemical profile with some documented clinical follow-up on individual patients. DATA EXTRACTION: The following parameters were monitored for patients from our institution: age, sex, possible exposure histories, tumor site, tumor size, type of therapy, clinical outcome, cytochemistry (Fontana-Masson stain), and immunohistochemical profile (S-100, HMB-45, vimentin, cytokeratin). The parameters of the meta-analysis were age, sex, tumor site, and survival data. DATA SYNTHESIS: Our patient population included 10 men and 15 women aged 23 to 83 years (mean, 65 years). Tumor sites included inferior turbinate, superior nasal cavity, nasal cavity floor/palate, ethmoid sinuses, and maxillary sinus. The immunohistochemical profile was as follows (positive cases): S-100 (14 of .14), HMB-45 (12 of 14), vimentin (9 of 10), cytokeratin (0 of 9). Melanin was demonstrated by Fontana-Masson stain (8 of 8 cases). Follow-up information was available in 25 cases, with follow-up ranging from 1 to 217 months (mean, 39 months). Eleven patients were disease free at 1 to 217 months (mean, 59 months) after excision. Local single recurrences developed in 6 patients at 3 to 84 months (mean, 14 months), and were treated with surgery. Multiple local recurrences were seen in 2 patients. One of them died of disseminated disease, after 2 local recurrences, 60 months after original diagnosis. The other was disease free after 38 months. Ten patients ultimately died of disease within 2 to 60 months after diagnosis (mean, 21 months). Only 2 patients may have developed metastatic disease in the absence of local recurrence. A total of 163 cases were identified from the literature: 53 women, 54 men (56 gender unknown). Stratification by era (pre-1980 vs post-1980) did not reveal any gender differences (pre-1980: 34 women [48%], 37 men [52%]; post-1980: 34 women [55%], 27 men [44%]). However, stratification by era did reveal an age shift toward older patients in the 1980-1995 era. The 5-year median survival for all patients was 36 months. Stratification by era of treatment revealed a long-term survival trend: patients treated before 1980 had somewhat better survival at 60 and 100 months (40% and 36%, respectively) than patients diagnosed and treated between 1980 and 1995 (30% and 23%, respectively), although statistical significance was not reached. CONCLUSION: It is unclear why the long-term survival for patients with sinonasal melanoma seems to be decreasing. Despite advances in imaging techniques, which would potentially allow for earlier tumor discovery, and advances in surgical techniques and adjuvant therapeutics, the mean survival for patients with sinonasal melanoma has not improved during the past 15 years.

Aged↗

PubMed1997

Intraoperative mapping of sensate flaps. Electrophysiologic techniques and neurosomal boundaries.

BACKGROUND: The desirability of restoring sensation to the upper aerodigestive tract has led to an expanded use of sensate flaps for reconstruction of mucosal defects. Sensation can be restored via preformed neural pathways through the anastomosis of recipient and donor nerves, provided that the sensate flap falls within the boundaries of the neurosome for the identified sensory nerve. OBJECTIVES: To perform detailed electrophysiologic mappings of neurosomes of potential sensate flap donor sites, to describe their variability, and to investigate the usefulness of intraoperative mapping in terms of flap design and harvesting. DESIGN: A case series of 27 patients who were undergoing free flap reconstruction of various postablative head and neck defects were examined. Two silver-silver chloride recording electrodes were placed in direct contact with the dissected sensory nerve, and the overlying skin was either mechanically or electrically stimulated. Auditory feedback, as well as visualization of the responses on an oscilloscope, determined whether the stimulated area fell within the neurosome. This technique was applied to the lateral antebrachial cutaneous nerve of the radial forearm flap (n = 15), the lateral sural cutaneous nerve of the fibula flap (n = 5), the subcostal nerve of the iliac crest flap (n = 6), and the dorsal cutaneous rami of spinal nerve T-1 or T-2 of the scapula flap (n = 1). RESULTS: The neurosome of the lateral antebrachial cutaneous nerve was relatively consistent with the variability only at the distal boundary (ie, the dorsum of the hand). The neurosome of the lateral sural cutaneous nerve was more variable, falling into 2 distinct innervation patterns: one showing innervation that was limited to the upper lateral and posterior portions of the calf and the other demonstrating significant extension into the lower half of the calf. The neurosome of the subcostal nerve showed little variability and consistently overlapped the proposed skin paddle. The neurosome of the T-1 or T-2 spinal nerve was mapped in 1 patient and is described. CONCLUSIONS: The consistency of neurosomal boundaries is dependent on the donor site. Intraoperative mapping of flap donor sites may not only assure the harvesting of a true sensate flap, but may also allow for intraoperative decision making with regard to possible modifications of flap design and harvesting techniques. Two new sensate flaps from the iliac crest and scapula are accurately described.

Adult↗

PubMed1997

Reconstruction of the laryngopharynx after hemicricoid/hemithyroid cartilage resection. Preliminary functional results.

OBJECTIVE: To evaluate the use of a sensate radial forearm free flap and free cartilage graft for reconstruction of the laryngopharyngeal defect that results from resection of pyriform sinus carcinoma that extends to the apex of the pyriform sinus and includes the hemithyroid and hemicricoid cartilages. DESIGN: Case series review of 6 patients treated during a 2 1/2-year period with an average follow-up of 23 months. Factors evaluated included oncologic outcome, as well as functional outcome with regard to the onset and quality of the airway, speech, and deglutition. SETTING: Mount Sinai School of Medicine, New York, NY, an academic, tertiary referral center. PATIENTS: Six men ranging in age from 51 to 73 years underwent a partial laryngopharyngectomy that included the hemicricoid and hemithyroid cartilages as well as the ipsilateral thyroid lobe and either unilateral or bilateral lymph node dissections for squamous cell cancer that involved the apex of the pyriform sinus. INTERVENTION: These extensive laryngopharyngeal defects were reconstructed with a sensate radial forearm flap that resurfaced the endolarynx, restored the depth of the pyriform sinus, and reconstructed the remainder of the hypopharynx. In the final 4 patients, a free costal cartilage graft was used to restore the infrastructure of the larynx. OUTCOME MEASURES: The status of the margins, the incidence and site of recurrent cancer, the quality of speech, and the times to decannulation and removal of the gastrostomy tube. RESULTS: Three recurrences developed, with 1 each at the primary site, in the neck, and systemically. All but 1 patient who had completed radiotherapy by the last follow-up had been decannulated, and all but 1 patient regained the ability to maintain nutrition by mouth. Complications were limited to pharyngocutaneous fistulae requiring surgical closure in 3 patients early in the series. CONCLUSIONS: Functional reconstruction of extensive laryngopharyngeal defects can be achieved with a sensate radial forearm flap and a cartilage graft, with favorable functional results and acceptable morbidity, thus expanding the limits of conservation laryngopharyngeal surgery.

Aged↗

PubMed1997

Reconstruction of massive defects in the head and neck: the role of simultaneous distant and regional flaps.

BACKGROUND: Massive defects resulting from excision of advanced head and neck tumors may not be amenable to reconstruction using a single technique of tissue transfer. Sixteen patients undergoing reconstruction using simultaneous free flaps and pedicled regional flaps are presented. METHODS: Regional flaps included the pectoralis major, deltopectoral, cervical visor, paramedian forehead, cervicofacial, and nape of neck flaps. Microvascular tissue transfers included the radial forearm, iliac crest, parascapular/latissimus dorsi, rectus abdominis, fibula, and lateral thigh free flaps. RESULTS: Most defects involved both aerodigestive mucosa and external cutaneous skin. Mucosal reconstruction was carried out using the soft-tissue component of the free flaps, whereas vascularized bone was used for mandibular reconstruction. Regional flaps were used to reconstruct skin of the face and neck. CONCLUSIONS: When planned and applied in a stepwise fashion, simultaneous free flaps and regional flaps are complimentary for the reconstruction of complex wounds in the head and neck.

Adult↗

PubMed1997

Continuous tissue oxygen tension measurement as a monitor of free-flap viability.

Early recognition of vascular compromise within microvascular free-tissue transfers is essential if reexploration is to prove successful. Tissue oxygen tension is increasingly recognized to be a sensitive and reliable index of tissue perfusion, and preliminary studies suggest that it may be of value in the assessment of free-flap viability. We describe our investigation into the application of an implantable microcatheter oxygen sensor in the monitoring of free flaps used in head and neck and extremity reconstruction. In a preliminary study using the rabbit model, we sought to evaluate the response of oxygen tension as an index of tissue perfusion in myocutaneous (n = 20) and osteomyocutaneous flaps (n = 5) under conditions of arterial and venous occlusion. A clinical study was then undertaken to evaluate the role of this method in the monitoring of surface and buried free flaps. In 30 heterogeneous free-tissue transfers, sensors placed intraoperatively were used to provide continuous information about flap oxygen tension (mean monitoring period 3.2 +/- 0.8 days). The data generated were correlated with changes in clinical parameters and routine flap observations. Results for experimental and clinical data have confirmed the efficacy of continuous tissue oxygen measurements using this device as a method that provides an objective, recordable index of free-tissue transfer viability in a variety of circumstances and vascular events. Tissue oxygen tension is a suitable index by which to evaluate flap viability with the probe placed in muscle or bone but is unreliable when used for the monitoring of revascularized cutaneous flaps.

Animals↗

PubMed1996

Lateral mandibular reconstruction using soft-tissue free flaps and plates.

OBJECTIVE: To assess the outcome of patients who are undergoing reconstruction of segmental lateral mandibular defects by using soft-tissue free flaps combined with mandibular reconstruction plates. DESIGN: Retrospective case series of 15 patients who were undergoing primary reconstruction of mandibular segments posterior to the mental foramen, resulting from treatment of head and neck cancer. All patients received either preoperative or postoperative radiation therapy. SETTING: Academic tertiary care referral center. INTERVENTIONS: Fourteen patients had mandibular continuity restored by using the titanium hollow screw reconstruction plate system, and 1 patient received a stainless steel mandibular reconstruction plate. Associated soft-tissue defects were repaired by using radial forearm (n = 11), rectus abdominis (n = 2), scapular and parascapular (n = 1), or lateral arm (n = 1) free flaps. MAIN OUTCOME MEASURES: Early and delayed complications. RESULTS: All 15 microvascular free tissue transfers were successful. Early complications were minor and occurred in 5 (33%) of 15 patients. One patient in whom the titanium hollow screw reconstruction plate system had been used experienced a fracture at 15 months after reconstruction. Three patients experienced delayed external plate exposure between 7 and 15 months after primary oromandibular reconstruction. Patients who experienced delayed external plate exposure required secondary reconstruction with a vascularized bone-containing free flap. The overall rate of delayed reconstructive failure was 40% in patients who were followed up for a minimum of 1 year. CONCLUSIONS: For patients who are undergoing free flap reconstruction of lateral mandibulectomy defects, the technique that used soft-tissue free flaps combined with mandibular reconstruction plates has been abandoned in favor of using vascularized bone-containing free flaps or a combination of free flaps to achieve optimal long-term results.

Adult↗

PubMed1996

Thrombolysis at a controlled pressure prolongs the survival of skin flaps treated with superoxide dismutase.

The role of thrombolysis in reestablishing patency in the microcirculation following ischemia, and thereby improving the efficacy of agents attenuating reperfusion injury, such as the oxygen free radical scavenger, superoxide dismutase (SOD), was investigated in a rat model. Abdominal skin flaps were subjected to normothermic ischemia induced by complete occlusion of the pedicle for periods of 12, 13, 14, 16, 18, 20, 22, and 24 hr. In Group 1 (n = 64), all animals received flap washout using 100,000U urokinase (manual injection) followed by 7,500 IU SOD given intra-arterially immediately prior to reperfusion. Animals in Group 2 received flap washout consisting of 100,000U urokinase given via a pressurized delivery system, followed by 7,500 IU SOD. Results demonstrated a statistically significant improvement in flap survival in Group 2. The authors concluded that thrombolytic therapy may be useful in improving the delivery of agents, such as SOD, which attenuate reperfusion injury in skin flaps.

Animals↗