Bone Regeneration of Canine Skull Using Bone Marrow-Derived Stromal Cells and β-Tricalcium Phosphate

OBJECTIVE

The aim of this study was to regenerate high-quality cranial bone using tissue engineering techniques, with subsequent extension to clinical application. Our previous study with a 3-month observation period indicated that a composite scaffold composed primarily of beta-tricalcium phosphate (TCP) had the potential for cranial bone regeneration. In this study, we investigated whether bone marrow derived stromal cells (BSCs) could promote the regeneration of cranial bone as determined after 3 and 6 months.

STUDY DESIGN

The pilot study was conducted with 14 adult beagle dogs.

MATERIALS AND METHODS

Craniotomy was performed in the same manner used clinically. The bone defect (2 x 2 cm) was created at each canine temporoparietal region. The test animals were divided into three groups. In group I, the bone defect was closed by replacing the original free bone flap without filling the residual gaps. In group II, the gap was filled with a composite scaffold consisting of collagen coated beta-TCP and autologous bone fragments with fibrin glue. In group III, autologous cultured BSCs and the composite scaffold were used to fill the gap. The sites of craniotomy were analyzed with three-dimensional computed tomography and histologic examination 3 and 6 months after the operation.

RESULTS

Bone regeneration was observed in groups II and III, with more extensive formation in group III than in group II. In group I, bone regeneration was not observed.

CONCLUSION

This study showed that BSCs have the potential to promote cranial bone regeneration and confirmed the efficacy of a composite scaffold made of beta-TCP and autologous bone fragments with fibrin glue.

In situ tissue engineering of the cricoid and trachea in a canine model

OBJECTIVES

The purpose of the current study was to demonstrate the efficacy of in situ tissue engineering of the cricoid and trachea in a canine model.

METHODS

Marlex mesh tube reinforced with polypropylene threads and covered by collagen sponge was used as a tissue scaffold for airway regeneration in 9 beagle dogs. The anterior half of the cricoid cartilage was resected in 5 dogs, whereas the cricoid cartilage and cervical trachea were simultaneously resected in 4 dogs. The tissue scaffold was implanted into the resultant defect.

RESULTS

Endoscopic examination showed no airway obstruction for a postoperative period of 3 to 40 months in all dogs. Granulation tissue was observed in 2 dogs, and slight mesh exposure in 1 dog, although all were asymptomatic. Light microscopy and electron microscopy showed the endolaryngeal and endotracheal lumen to be covered by ciliated epithelium. According to strain-force measurement, the framework was firmly supported by regenerated tissue, as well as the normal cricoid and trachea.

CONCLUSIONS

Our current tissue scaffold provides a rigid framework for the airway, and the collagen coating invites tissue regrowth around the tube. This study presents the possibility of successful reconstruction of the cricoid and trachea with epithelial regeneration by means of in situ tissue engineering.

An endogenous regulator of inflammation, resolvin E1, modulates osteoclast differentiation and bone resorption

BACKGROUND AND PURPOSE

The inflammation-resolving lipid mediator resolvin E1 (RvE1) effectively stops inflammation-induced bone loss in vivo in experimental periodontitis. It was of interest to determine whether RvE1 has direct actions on osteoclast (OC) development and bone resorption.

EXPERIMENTAL APPROACH

Primary OC cultures derived from mouse bone marrow were treated with RvE1 and analysed for OC differentiation, cell survival and bone substrate resorption. Receptor binding was measured using radiolabelled RvE1. Nuclear factor (NF)-kappaB activation and Akt phosphorylation were determined with western blotting. Lipid mediator production was assessed with liquid chromatography tandem mass spectrometry.

KEY RESULTS

OC growth and resorption pit formation were markedly decreased in the presence of RvE1. OC differentiation was inhibited by RvE1 as demonstrated by decreased number of multinuclear OC, a delay in the time course of OC development and attenuation of receptor activator of NF-kappaB ligand-induced nuclear translocation of the p50 subunit of NF-kappaB. OC survival and apoptosis were not altered by RvE1. Messenger RNA for both receptors of RvE1, ChemR23 and BLT(1) is expressed in OC cultures. Leukotriene B(4) (LTB(4)) competed with [(3)H]RvE1 binding on OC cell membrane preparations, and the LTB(4) antagonist U75302 prevented RvE1 inhibition of OC growth, indicating that BLT(1) mediates RvE1 actions on OC. Primary OC synthesized the RvE1 precursor 18R-hydroxy-eicosapentaenoic acid and LTB(4). Co-incubation of OC with peripheral blood neutrophils resulted in transcellular RvE1 biosynthesis.

CONCLUSIONS AND IMPLICATIONS

These results indicate that RvE1 inhibits OC growth and bone resorption by interfering with OC differentiation. The bone-sparing actions of RvE1 are in addition to inflammation resolution, a direct action in bone remodelling.

Replacement of the left main bronchus with a tissue-engineered prosthesis in a canine model

BACKGROUND

Stenosis of the left main bronchus caused by inflammatory diseases and neoplasms is a serious clinical problem because it can cause obstructive pneumonia and may require pneumonectomy. As an alternative to various treatments currently available, including balloon dilatation, stenting, and bronchoplasty, we propose the use of a prosthesis developed based on the concept of in situ tissue engineering for replacement of the left main bronchus.

METHODS

The main frame of the tissue-engineered prosthesis is a polypropylene mesh tube, 12 to 15 mm in inner diameter and 30 mm in length, with reinforcing rings. Collagen extracted from porcine skin is conjugated to this frame. A consecutive series of 8 beagle dogs underwent replacement of the left main bronchus with this tissue-engineered prosthesis.

RESULTS

All dogs survived the postoperative period with no morbidity except 1, which required intravenous administration of antibiotic for a week for pneumonia and recovered. Three dogs were euthanized for examination at 3 and 4 months after bronchus replacement, and the other five were monitored for more than 1 year. In two dogs, histologic examination revealed that the luminal surface was completely covered with ciliated columnar epithelium or nonciliated squamous epithelium. Exposure of the polypropylene mesh to various degrees was observed in 6 dogs, but the prosthesis remained stable and no adverse effects such as infection, sputum retention, or dehiscence were observed.

CONCLUSIONS

These long-term results suggest that our tissue-engineered prosthesis is applicable for replacement of the left main bronchus.

Clinical Application of in Situ Tissue Engineering Using a Scaffolding Technique for Reconstruction of the Larynx and Trachea

Objectives:

The objective of the present study was to demonstrate the efficacy of the clinical application of in situ tissue engineering using a scaffolding technique for laryngeal and tracheal tissue.

Methods:

We have developed a tissue scaffold made from a Marlex mesh tube covered by collagen sponge. Based on successful animal experimental studies, in situ tissue engineering with a scaffold implant was applied to repair the larynx and trachea in 4 patients.

Results:

In 1 patient with subglottic stenosis, the thyroid cartilage, cricoid cartilage, and cervical trachea with scarring and granulation were resected and reconstructed by use of the scaffold. In 3 patients with thyroid cancer, the trachea and cricoid cartilage with tumor invasion were resected and the scaffold was implanted into the defect. Postoperative endoscopy during the observation period of 8 to 34 months showed a well-epithelialized airway lumen without any obstruction.

Conclusions:

Our current technique of in situ tissue engineering using a scaffold shows great potential for use in the regeneration of airway defects.

Regeneration of the Trachea Using a Bioengineered Scaffold with Adipose-Derived Stem Cells

Objectives:

Our group has developed and clinically applied an artificial graft made from a collagen sponge scaffold for the regeneration of tracheal tissue. However, the artificial graft requires about 2 months for epithelial regeneration. The purpose of the present study was to accelerate the regeneration process of the trachea through the effective use of a bioengineered scaffold. Adipose-derived stem cells (ASCs) with multilineage differentiation capability were used. In our study, we implanted a bioengineered scaffold that included autologous ASCs into tracheal defects in rats.

Methods:

Collagen gel, including ASCs labeled with monomeric yellow fluorescent protein, was layered onto the surface of the collagen sponge to form a bioengineered scaffold. This scaffold was implanted into the tracheal defects in rats. A control scaffold without ASCs was also implanted.

Results:

On day 14 after implantation, a pseudostratified columnar epithelium with well-differentiated ciliated and goblet cells and neovascularization was observed in rats that received the implant with the bioengineered scaffold that included ASCs.

Conclusions:

These results suggested that implanted ASCs accelerated neovascularization and epithelialization on the regenerated trachea. Thus, our newly developed bioengineered scaffold contributes to tracheal regeneration.

Regeneration of Tracheal Epithelium Utilizing a Novel Bipotential Collagen Scaffold

Objectives:

The purpose of the present study was to evaluate the effectiveness of a novel bipotential collagen scaffold as a bioengineered trachea for the regeneration of the tracheal epithelium.

Methods:

The bipotential collagen scaffold was developed by conjugating a collagen vitrigel membrane to a collagen sponge in order to promote both epithelial cell growth and mesenchymal cell infiltration. The bipotential collagen scaffold was transplanted into tracheal defects in rats, and a conventional collagen sponge was implanted as a control model. Histologic examinations were undertaken to evaluate the results.

Results:

The bioengineered trachea was covered with epithelium in the vitrigel model, but not in the control model, at 7 days after implantation. At 14 days after implantation, the bioengineered trachea was covered with epithelium involving the basal cell layer in the vitrigel model. At 28 days after implantation, a columnar ciliated epithelium was observed only in the vitrigel model.

Conclusions:

Our technique for trachea reconstruction using a novel bipotential collagen scaffold affords a feasible approach for accelerating epithelial regeneration on the intraluminal surface of the host tracheal defect.

Effect of Fibroblasts on Epithelial Regeneration on the Surface of a Bioengineered Trachea

Objectives:

Our group applied a tracheal prosthesis, which was composed of polypropylene as the frame and collagenous sponge as the scaffold, to the first human case and had successful results. The objective of this study was to find a way to acquire more rapid re-epithelialization with fibroblasts on this tracheal prosthesis.

Methods:

Tracheal epithelial cells, which were isolated from the trachea of rats, were suspended in a collagenous gel. The collagenous gel with fibroblasts was layered on a collagenous sponge. The grafts of this “bioengineered trachea” were implanted into tracheal defects of rats, and the regenerated epithelium on the grafts was histologically examined.

Results:

Seven days after implantation, stratified squamous epithelium covered almost all of the surface of the gel, and some of the implanted fibroblasts in the gel were lined up just below the epithelium. Fourteen days after implantation, columnar and cuboidal ciliated epithelium covered almost all of the surface of the defects, and the implanted fibroblasts had disappeared. The numbers of regenerated epithelial cells at 14 days after implantation were larger than those of control models without fibroblasts, with statistical significance.

Conclusions:

The results suggested that the grafts of bioengineered trachea composed of collagenous sponge and collagenous gel with tracheal fibroblasts accelerated epithelial differentiation and proliferation in vivo.

Potential of Heterotopic Fibroblasts as Autologous Transplanted Cells for Tracheal Epithelial Regeneration

The tracheal epithelium maintains the health of the respiratory tract through mucociliary clearance and regulation of ion and water balance. When the trachea is surgically removed, artificial grafts have been clinically used by our group to regenerate the trachea. In such cases, the tracheal epithelium needs 2 months for functional regeneration. Previous study has shown that fibroblasts facilitate tracheal epithelial regeneration. In this study, heterotopic fibroblasts originating from the dermis, nasal, and gingival mucosa were cocultured with tracheal epithelial cells to evaluate their potential as autologous transplanted cells for tracheal epithelial regeneration. The epithelia induced by the heterotopic fibroblasts showed differences in structure, cilia development, mucin secretion, and expression of ion and water channels. These results indicated that nasal fibroblasts could not induce mature tracheal epithelium and that dermal fibroblasts induced epidermis-like epithelium. Only the gingival fibroblasts (GFBs) could induce morphologically and functionally normalized tracheal epithelium comparable to the epithelium induced by tracheal fibroblasts. Epithelial cell proliferation and migration were also upregulated by GFBs. These results indicate that GFBs are useful as autologous transplant cells for tracheal epithelial regeneration.

Improvement of human islet cryopreservation by a p38 MAPK inhibitor

The activation of p38 mitogen-activated protein kinase (MAPK) has been shown to cause ischemia/reperfusion injury of several organs used for transplantation and also to play a significant role in primary islet graft nonfunction. Activation of p38 MAPK may also occur during islet cryopreservation and thawing. In this study, a p38 MAPK inhibitor (p38IH) was applied to human islet cryopreservation to improve islet yield and quality after thawing. Under serum-free conditions, human islets were cryopreserved, thawed and cultured using our standard procedures. Three types of solutions were tested: conventional RPMI1640 medium (RPMI), a newly developed islet cryopreservation solution (ICS), and ICS supplemented with a p38IH, SD-282 (ICS-p38IH). Activation or inhibition of p38 MAPK was demonstrated by the diminished phosphorylation of HSP27 substrate. Islet recovery on day 2 after thawing was highest with ICS-p38IH and islet viability was not significantly different in the three groups. beta Cell numbers and function were the highest in islets cryopreserved with ICS-p38IH. Glucose-stimulated human C-peptide levels were 86% of that of the nonfrozen islets when measured 4 weeks after transplantation into NODscid mice. This improvement may provide an opportunity to establish islet banks and allow the use of cryopreserved islets for clinical transplantation.

Tracheal regeneration after partial resection: a tissue engineering approach

OBJECTIVES

The aims of this study are to investigate the efficiency of a tissue engineering approach to partial tracheal reconstruction and to improve epithelialization of the reconstructed trachea. The trachea must be resected in some cases of cancer or trauma. Various restructuring techniques are used, with no consensus on the best approach. Two problems that arise when treating tracheal defects by conventional techniques are an inability to regenerate ciliated epithelium at the reconstructed site and having to perform multiple procedures to achieve the desired repair. This study is designed to address these problems.

STUDY DESIGN

Preliminary, an animal experiment.

METHODS

Surgery was performed on five adult beagles under anesthesia. After the making of a longitudinal cervical skin incision, the trachea was exposed and a circular defect created. A polypropylene and collagen scaffold preclotted with peripheral blood was inserted to the defect site. Postoperatively, the site was evaluated fiberscopically, histologically, and radiographically.

RESULTS

All dogs did well postoperatively. Fiberscopic examination showed that the implanted scaffolds were completely covered with regenerated mucosa with capillaries in all cases. Histologic data showed ciliated epithelium regenerated at the operated site from 1 month postoperatively. Newly formed cartilage was detected in the specimens from 8 to 12 postoperative months. Computed tomography images revealed the fine luminal contour of the regenerated site.

CONCLUSIONS

Good epithelial regeneration was observed after repair of a round tracheal resection using a simple tissue engineering technique, making the technique a good substitute for conventional approaches to tracheal reconstruction in patients with cancer or trauma.

Etiology of severe sensorineural hearing loss in children: independent impact of congenital cytomegalovirus infection and GJB2 mutations

BACKGROUND

Sensorineural hearing loss (SNHL) is the most common congenital disease. Longitudinal studies of infants with congenital cytomegalovirus (CMV) infection have demonstrated an association between CMV and SNHL. However, because of the lack of suitable neonatally collected specimens, the proportion of CMV-associated SNHL has not been defined, nor has the relationship between CMV and the major genetic causes of SNHL, such as mutations in the GJB2 gene.

METHODS

Sixty-seven children with severe SNHL were analyzed for CMV and human herpesvirus 6 (HHV-6) infections and for GJB2 mutations. DNA specimens were prepared from dried umbilical cords, which are available for everyone born in Japan. Four children with typical symptomatic infection at birth served as positive control subjects.

RESULTS

Congenital CMV infection and GJB2 mutations were identified in 15% and 24% of the patients, respectively. HHV-6 was not detected. All children with CMV-associated cases developed SNHL before they were 2 years old. Most children with CMV-associated SNHL had no obvious clinical abnormality at birth, and their viral loads were lower than those of symptomatic children.

CONCLUSIONS

Congenital CMV infection is an important cause of severe SNHL, and it has an incidence comparable to that of GJB2-associated SNHL.

Stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty--Muffler method

CONCLUSION

High success rates of recovery of hearing level in type III and IV tympanoplasty could be achieved by this stabilization technique for columella using trimmed autologous temporal fascia.

OBJECTIVE

The aim of this study was to evaluate a new stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty.

PATIENTS AND METHODS

A total of 55 patients (21 male, 34 female, aged 4-85 years) with chronic otitis media (n=16) and cholesteatoma (n=39) underwent tympanoplasty using this new stabilization technique for columella. Thirty-one patients underwent type III tympanoplasty and 24 patients underwent type IV tympanoplasty. Forty-two patients underwent a staged operation and 13 patients underwent a single operation. The observation period was 3.5 years from 6 months after the last operation.

RESULTS

The overall success rates in type III and IV tympanoplasty were 87.1% (27/31) and 83.3% (20/24), respectively. Two of eight patients for whom the procedure was unsuccessful underwent reoperation and they acquired good hearing.

5-Fluorouracil Ointment for the Treatment of Otitis Media With Effusion

OBJECTIVES/HYPOTHESIS

Our aim was to evaluate the combined effect of 5-fluorouracil (5-FU) and myringotomy for the treatment of otitis media with effusion (OME). OME is usually treated with medication, myringotomy, or insertion of a ventilation tube (VT). Except for VT insertion, however, treatment effects are short-lived. VT insertion has numerous sequelae: increased susceptibility to infection, large perforation of the tympanic membrane, cholesteatoma, and eventual hearing deterioration. We estimated the depressant action of 5-FU on normal cell proliferation in vitro. In addition, clinically, we assessed whether 5-FU has the potential to prolong the effect of myringotomy.

STUDY DESIGN

An in vitro study and a clinical study were conducted.

MATERIALS AND METHODS

In study I, fibroblasts harvested from the peritoneum of three green fluorescent protein transgenic mice were cultured with different doses of 5-FU. After 2 weeks, their proliferation rates were compared. In study II, patients (54 males, 47 females) were selected randomly from a group of patients with intractable OME. Myringotomy with or without a single dose of 5-FU ointment (approximately 0.10-0.30 mg) was performed in group I (n = 64) and group II (n = 37), respectively. The natural closure rates of the tympanic membrane were assessed in both groups.

RESULTS

In vitro, 5-FU inhibited the growth of fibroblasts in a dose-dependent manner. The average time to tympanic membrane closure was 20.5 days in group I and 8.1 days in group II. No adverse events were observed in either group.

CONCLUSIONS

Topical application of 5-FU ointment is useful in prolonging the effect of myringotomy. 5-FU ointment therapy is easy, safe, and cost-effective and may be of wide application.

Experimental regeneration of canine larynx: a trial with tissue engineering techniques

CONCLUSION

Since this tissue engineering technique is cost-effective and is less invasive to patients, it may replace conventional approaches in laryngeal reconstructive surgeries.

OBJECTIVE

Laryngeal cancer is one of the most prevalent cancers in the head and neck region, and frequently requires surgical resection. Although there are many ways to reconstruct the larynx after resection, donor tissue is usually required. Recently, tissue engineering techniques have become widely accepted in clinical medicine and have already been applied to some organs. This animal experiment was designed to elucidate the efficacy of laryngeal regeneration using tissue engineering technique.

MATERIALS AND METHODS

A bioartificial scaffold was designed from a replica of a canine larynx. A dental cast was used to replicate the intricate inside shape of the larynx. After copying its shape on a polypropylene mesh sheet, this sheet was coated with spongy collagen from porcine skin. A hemilaryngectomy was performed on beagle dogs under general anesthesia. Then the scaffold, preclotted with a mixture of peripheral blood and bone marrow-derived stromal cells, was implanted and fixed. The postoperative status was examined fiberscopically.

RESULTS

On the eighth day after the operation, the surface of the implant was covered with soft tissue. Finally, the implant was completely covered with regenerated mucosa.

Congenital Cytomegalovirus Infection Diagnosed by Polymerase Chain Reaction With the Use of Preserved Umbilical Cord in Sensorineural Hearing Loss Children

OBJECTIVES/HYPOTHESIS

Congenital cytomegalovirus (CMV) infection is estimated to account for 30% of sensorineural hearing loss (SNHL) cases. Differences in clinical characteristics between CMV-related and unrelated SNHL cases were scrutinized.

METHODS

Using dried umbilical cord, we have recently developed a polymerase chain reaction (PCR)-based assay for the retrospective detection of congenital CMV infection. Medical records of 7 CMV-related patients identified from 31 SNHL patients by the assay were evaluated for the following: type and degree of hearing impairment, computed tomographic scan results, mental retardation, cerebral palsy, autism, and other multiple disorders.

RESULTS

Clinical characteristics of the seven CMV-related SNHL cases were as follows: 1) six of the seven exhibited severe bilateral SNHL, whereas one had severe unilateral SNHL in the right ear. Although the hearing levels of CMV-related patients were more greatly impaired than those of CMV-negative patients, there was no hearing impairment pattern specific to the CMV-related patients; 2) five patients had mental retardation, which was more frequent than in CMV-negative patients; 3) birth weights of the CMV-positive cases were relatively lower.

DISCUSSION

Although CMV-positive cases are clinically indistinguishable from CMV-negative cases, our PCR system allowed the retrospective diagnosis of CMV-related SNHL.

CONCLUSION

CMV-related SNHL tends to accompany mental retardation and low birth weight more frequently than does CMV-negative SNHL.

Age-dependent degeneration of the stria vascularis in human cochleae

OBJECTIVE

Aging is a common cause of acquired hearing impairments. This study investigated age-related morphologic changes in human cochleae, with a particular focus on degeneration of the stria vascularis (SV) and the spiral ganglion (SG).

STUDY DESIGN

Retrospective case review.

METHODS

The study group comprised 91 temporal bones from individuals aged 10 to 85 years who had no history or audiometric findings suggestive of specific causes of cochlear degeneration. We quantified the SV and SG atrophy at each cochlear turn using morphometric measurements. Correlations of the SV and SG atrophy with age, audiometric patterns of hearing loss, and auditory thresholds were statistically investigated.

RESULT

The SV and the SG both showed a tendency for progressive atrophy to develop with age. However, statistically significant correlations were observed between aging and SV atrophy only in the apical and basal cochlear turns. These findings were consistent with those reported previously in gerbils. No significant correlations were detected between SV or SG atrophy and audiometric findings.

CONCLUSION

SV atrophy appears to be the most prominent anatomic characteristic of aged human cochleae.

Effect of Fibroblasts on Tracheal Epithelial Regenerationin vitro

Several artificial grafts for covering deficient trachea have been produced through tissue engineering. Recently, our group clinically used an artificial trachea made from collagen sponge for patients with noncircumferential tracheal resection. However, the slowness of epithelial regeneration on the surface of the artificial trachea was confirmed as one particular problem. In this study, we co-cultured tracheal epithelial cells with fibroblasts and examined effects of fibroblasts on epithelial regeneration in vitro. Fibroblasts activated epithelial cell proliferation and migration. In co-culture with fibroblasts, epithelial cells reconstructed pseudostratified epithelium, which was composed of ciliated, goblet, and basal cells. Furthermore, a basement membrane was reconstructed between epithelial cells and fibroblasts, and integrin beta4 was also observed there. Fibroblasts rapidly increased mucin secretion by epithelial cells. These results indicate that stimulatory effects of fibroblasts on epithelial cell migration, proliferation, and differentiation would reduce the time required for covering of epithelial cells on the defect of luminal surface and hasten regeneration of morphologically and functionally normalized epithelium involving the reconstruction of basement membrane.

Analysis of 95 cases of squamous cell carcinoma of the external and middle ear

OBJECTIVE

To analyze the clinical characteristics, 5-year survival, and prognostic factors of squamous cell carcinoma (SCC) of the external and middle ear.

METHODS

A multi institutional study. Ninety five cases of patients from 10 institutions were reviewed on their age and sex distribution, initial complaints, stages, tumor locations, treatments, and outcomes. Prognostic factors were discussed based on the Pittsburgh staging system.

RESULTS

This disease seems to appear in the elderly with a peak age of 50-69 years. Males appear to be more predisposed than females with an odd ratio of 1.7. The initial complaints were not typical, while 12.6% of patients presented a history of recurrent otitis externa or chronic otitis media. Regional metastasis was recognized in 13.7% of patients, while no distant metastasis was confirmed. SCC located in the external ear could be detected in an earlier stage than that in the middle ear. The overall 5-year survival was 66.8% in total, and decreased significantly with stage. SCC in stages I and II was susceptible to each therapeutic strategy with a 5-year survival of 100%. Operation combined with radiotherapy and/or chemotherapy was the major treatment for stages III and IV SCC, while radiotherapy and chemotherapy were applied mainly for those who had been considered inappropriate for operation. The overall survival was 67.2% for stage III and 29.5% for stage IV, and operation with pathologically tumor free margin could improve the survival to 72.7% when combined with radio- and chemotherapy. Stage, completeness of operation with tumor free margin, recurrence, and metastasis have significant influence on survival.

CONCLUSION

Local infiltration seems to be the main behavior of SCC in the external and middle ear. Early diagnosis and treatment were important because SCC in the earlier stage is susceptible to be cured. For tumors of advanced stage, operation should be performed with pathologically tumor free margin, and operation combined with radiotherapy and chemotherapy could improve the survival. Tumor stage adds more influence on survival than its location. Recurrence and metastasis mainly occur in advanced stages and result in a poor survival.