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Biomedical subjects

D M Toriumi

Publications and source records attributed to D M Toriumi.

At least 19 recordsLinked to original sources
PubMed1991

Mandibular reconstruction with a recombinant bone-inducing factor. Functional, histologic, and biomechanical evaluation.

Bone morphogenetic protein-2 (BMP-2) is a human recombinant bone-inducing factor that stimulates bone formation within 14 days. Twenty-six dogs underwent reconstruction of 3-cm full-thickness mandibular defects. After stabilizing the defects with stainless steel reconstruction plates, test implants composed of inactive dog bone matrix carrier and human recombinant BMP-2 were placed in defects of 12 animals (group 1). Control implants (carrier without BMP-2) were used in 10 animals (group 2), and no implants were placed in mandibular defects of four animals (group 3). Animals were killed at 3 and 6 months. The reconstructed segments were evaluated by roentgenography, analysis of functional stability, histology, histomorphometry, and analysis of biomechanical strength using three-point bend testing. In group 1, reconstruction plates were removed at 10 weeks because stiff, noncompressible mineralized bone formed across the defects, allowing the animals to chew a solid diet. The defects from groups 2 and 3 showed minimal, if any, bone formation and remained grossly unstable, prohibiting plate removal or advancement to a solid diet. Histomorphometric analysis at 6 months revealed that 68% of the group 1 implants were replaced by mineralized bone, whereas mineralized bone occupied less than 4% of the implants in groups 2 and 3. Biomechanical testing at 6 months revealed that the average bending strength of the reconstructed hemimandibles (expressed as a percentage of the contralateral hemimandible) was 27% for group 1 and 0% for group 2. The biomechanical strength of the defects reconstructed with BMP-2 increased significantly from 3 to 6 months and was related to degree of mineralization and thickness of bone bridging the defect.

Animals↗
PubMed1991

Variable histotoxicity of histoacryl when used in a subcutaneous site: an experimental study.

Histoacryl (butyl-2-cyanoacrylate) is one of the least histotoxic cyanoacrylate derivatives and is used as a tissue adhesive. Clinical applications primarily include skin closure (blepharoplasty incisions, etc.). In a recent study, we demonstrated that Histoacryl elicits minimal histotoxicity when used to glue bone grafts to rabbit-ear cartilage. Acute inflammation was limited to areas where Histoacryl escaped from between the bone graft and ear cartilage to contact well-vascularized soft tissue. In this study, Histoacryl was applied between bone graft and cartilage in one rabbit ear and adjacent to well-vascularized soft tissue with no graft in the opposite ear. Histologic analysis revealed minimal if any inflammation when small amounts of glue was used in the nonvascular region between bone graft and cartilage. However, subcutaneous implantation contacting well-vascularized soft tissue resulted in increased acute inflammation and prolonged foreign-body giant-cell response. Further studies are required to rule out any long-term problems associated with subcutaneous implantation of Histoacryl.

Administration, Cutaneous↗
PubMed1991

Bone-inducing implants in head and neck surgery: an experimental study.

The use of autologous bone for head and neck reconstruction requires a separate harvesting procedure which provides limited quantities of bone that may become infected or undergo resorption after being implanted. In this study, a collagen/ceramic carrier containing osteoinductive factor extract (OFE) was used in a rabbit facial augmentation model. Bone-inducing activity of these implants were evaluated in subcutaneous, intramuscular, and subperiosteal sites. Implants with (test) and without OFE (control) were placed on opposite sides of the face in 40 rabbits, and were harvested at 21 days. Bone formation was evaluated by implant alkaline phosphatase determinations and histomorphometry. Osteoblastic activity, bone formation, and preservation of facial augmentation were noted in the OFE implants, showing maximal bone formation when implanted subperiosteally. Control (no OFE) and demineralized bone implants showed no bone formation. Before these implants can be used clinically, novel bone-inducing factors must be manufactured by recombinant deoxyribonucleic acid (DNA) methodology to verify activity of the homogeneous molecule which would be free of other proteins or infectious agents.

Alkaline Phosphatase↗
PubMed1990

Histotoxicity of cyanoacrylate tissue adhesives. A comparative study.

Cyanoacrylate derivatives have been used as surgical adhesives for many years. Shorter-chain derivatives (methyl- and ethyl-cyanoacrylate) have proved to be histotoxic. Longer-chain derivatives (butyl- and isobutyl-cyanoacrylate) are much less histotoxic. Many surgeons continue to use ethyl-2-cyanoacrylate (Krazy Glue) despite the availability of a less toxic derivative, butyl-2-cyanoacrylate (Histoacryl). In this study, the histotoxicity and bone graft-cartilage binding ability of Krazy Glue and Histoacryl were compared. Bone grafts harvested from the anterior wall of the maxillary sinus were placed in a subcutaneous pocket and glued to auricular cartilage in the rabbit. Krazy Glue and Histoacryl were used in opposite ears, harvesting specimens at 1, 2, 4, 12, 24, and 48 weeks. The Krazy Glue-treated ears developed seromas with histologic evidence of acute inflammation, tissue necrosis, and chronic foreign body giant cell reaction. The Histoacryl-treated ears showed mild acute inflammation and mild foreign body giant cell reaction. The Krazy Glue was completely degraded within 12 months, while some Histoacryl was still present at 1 year. Histoacryl had minimal histotoxic effect and good bone graft-cartilage binding ability, whereas Krazy Glue demonstrated severe histotoxicity.

Animals↗
PubMed1990

Demineralized bone. Implant resorption with long-term follow-up.

The osteoinductive properties of demineralized bone have stimulated its use in facial skeletal augmentation and reconstruction. Demineralized bone has been shown to induce phenotypic conversion of mesenchymal cells into osteoblasts, with bone formation within 29 days (osteoinduction). In this clinical study, 75 demineralized bone implants were followed up from 1 to 48 months (average follow-up, 14.3 months). There were 41 major dorsal implants, with an average degree of resorption of 50.7%. Eight dorsal implants were followed up for more than 24 months, with an 82.5% degree of resorption. Overall resorption for all implants was 49%. Major factors contributing to implant resorption included lack of surrounding mesenchymal cells and inadequate contact between host tissue and bone-inducing surface area. Other factors included infection, poor vascularity, and compression of the implant. Demineralized bone has an unacceptably high resorption rate and should only be used in highly selective cases where the implant can be positioned in a site rich in primitive mesenchymal or bone-forming cells.

Bone Density↗
PubMed1990

Management of the aging forehead.

Browlifting and forehead procedures are a critical element in the contemporary surgical management of the aging face. Esthetics of the upper third of the face will dictate brow position and its relationship to the supraorbital rim and eyes. Treatment of deformities of the upper third of the face can be varied according to the sex and age of the patient as well as contour of the hairline and forehead. The indications, advantages, disadvantages, and techniques of the coronal forehead, modified pretrichal forehead, midforehead, and direct browlifting procedures are discussed.

Aged↗
PubMed1990

Rationale for elective neck dissection in 1990.

Elective neck dissection has long been a subject of debate among surgeons. The proponents of elective neck dissection base their rationale on studies that show a 30% incidence of occult disease in those situations for which elective neck dissection is recommended. One hundred eighty-two patients with advanced stages of squamous cell carcinoma of the head and neck were studied. All patients had preoperative computed tomography or magnetic resonance imaging, and all patients had some form of radical neck dissection. The sensitivity of clinical exam was compared with the sensitivity of computed tomography or magnetic resonance imaging in ability to detect nodal disease. The sensitivity of clinical exam alone was 71.7%, while the sensitivity of computed tomography or magnetic resonance imaging was 91.1%. Based on physical exam alone, there would be a 39% rate of occult disease; if computed tomography or magnetic resonance imaging data is combined with physical exam, the occult disease rate would drop to 12%. All centers performing elective neck dissection must reassess their rationale or restudy their occult disease rate with computed tomography or magnetic resonance imaging.

Carcinoma, Squamous Cell↗
PubMed1989

Esophageal stethoscope. Another possible cause of vocal cord paralysis.

Hoarseness after endotracheal intubation can result from compression of the anterior branch of the recurrent laryngeal nerve as it passes behind the thyroid cartilage to innervate the lateral cricoarytenoid muscle. This usually occurs when the cuff of the endotracheal tube lies in the larynx instead of the trachea. When a nasogastric tube is positioned in the midline, resultant postcricoid inflammation can result in vocal cord immobility. This may result from neuropraxia of the posterior branch of the recurrent laryngeal nerve that innervates the posterior cricoarytenoid and interarytenoid muscles, or inflammatory spasm of the interarytenoid muscles themselves. We present a case of vocal cord paralysis after general anesthesia that may have been caused by an esophageal stethoscope. The mechanism for vocal cord immobility could be similar to that of a midline nasogastric tube with resultant postcricoid inflammation. We describe measures that can be taken to prevent vocal cord paralysis after intubation of the larynx or esophagus.

Adult↗
PubMed1989

Implantation of a recurrent laryngeal nerve stimulator for the treatment of spastic dysphonia.

Spastic dysphonia, a rare speech disorder, is characterized by strained phonation with excessively adducted vocal cords. Recurrent laryngeal nerve section, botulinum toxin injection into the vocalis-thyroarytenoid muscle complex, and other techniques have been used to treat this disorder. We have used percutaneous electrical stimulation of the recurrent laryngeal nerve with good results. Previous dog studies demonstrated the relative safety of an implantable recurrent laryngeal nerve stimulator. In this study, we directly stimulated the recurrent laryngeal nerve and vagus nerve in a dog without change in cardiorespiratory status. A Medtronic peripheral nerve stimulator was implanted in a patient with abductor spastic dysphonia. The cuff electrode was positioned around the recurrent laryngeal nerve and stimulation resulted in improvement in her voice. Extensive cardiopulmonary monitoring did not reveal any adverse response to stimulation and there was no discomfort to the patient. On the basis of the good results of this preliminary study, further study with long-term follow-up is under way.

Adult↗
PubMed1989

Paranasal sinus malignancy: a comprehensive update.

A retrospective analysis of 60 cases of paranasal sinus cancer in patients admitted between 1970 and 1985 was undertaken. Forty-six tumors originated in the maxillary sinus, and 14 originated in the ethmoid sinuses. Computed tomography, magnetic resonance imaging, and endoscopic sinus examination aided in early diagnosis of sinus cancer. Computed tomography aided in staging tumors; Caldwell-Luc alone was inadequate for staging tumors invading deeper sites such as the orbits or pterygoid muscle. There were 15 early (T1 or T2) and 31 advanced (T3 or T4) maxillary sinus cancers. Multimodality therapy incorporated radiation, surgery, and chemotherapy. The 5-year survival rate was 49%. We prefer preoperative radiotherapy for advanced lesions and postoperative radiotherapy for early lesions. The use of preoperative radiation therapy has increased our globe salvage rate. All but one of the patients who developed recurrent disease showed recurrence at the primary site prior to developing regional or distant metastasis. Radiation therapy, combined with aggressive surgical management to remove all tumor, provided the best survival rates in advanced lesions.

Adult↗
PubMed1989

[Epiglottitis in the adult. A proposition for a clinical classification and therapeutic strategy].

Because lack of criteria for staging and treatment of epiglottitis can lead to unnecessary morbidity and mortality, we have introduced a staging system for early classification and appropriate management of adult epiglottitis patients. We retrospectively staged 20 adults with epiglottitis to see in their final outcome would have been altered using our protocol. We found that staging and management according to our protocol were appropriate and possibly could have reduced mortality from 10% to nearly 0%.

Adult↗
PubMed1989

Cavernous hemangioma of the infratemporal fossa.

Cavernous hemangiomas are most commonly found in the head and neck region. We report a case of infratemporal fossa cavernous hemangioma. Extensive workup included CT scan, MRI, and angiography. Treatment involved surgical excision using the Weber-Ferguson approach. Successful excision of the tumor was possible because of accurate preoperative localization of the mass, as well as morphologic examination that ruled out those infratemporal fossa tumors requiring different surgical approaches.

Adult↗
PubMed1989

The effect of a temporary nasoantral window on mucociliary clearance. An experimental study.

Although many studies have clearly shown that nasoantral windows do not help ciliary clearance of sinus disease, studies have not addressed the possible adverse effects of nasoantral windows. This study was performed to determine if an inferior antrostomy can actually improve ciliary clearance. Even with the advent of endoscopic sinus surgery we need to have a better understanding of inferior antrostomies.

Animals↗