AlloDerm tympanoplasty of tympanic membrane perforations

Pediatric Primary Tympanoplasty Outcomes With Autologous and Non-autologous Grafts

OBJECTIVE

To compare rates of successful tympanic membrane (TM) closure in primary pediatric tympanoplasty between various autologous and non-autologous tissues.

METHODS

A retrospective chart review was performed examining all primary pediatric tympanoplasties over a 20-year period at a single institution.

RESULTS

In 564 pediatric tympanoplasties, no statistically significant difference existed between success rates of autologous and non-autologous grafts (p = 0.083). Compared with fascia, the hazard ratios (and 95% confidence intervals [CI]) for failure for each graft were as follows: human pericardial collagen (HR 0.90, CI 0.54-1.50, p = 0.680), porcine submucosal collagen (HR 1.07, CI 0.56-2.05, p = 0.830), human acellular dermal collagen (HR 1.66, CI 0.95-2.87, p = 0.073), and "multiple grafts" (HR 0.72, CI 0.26-1.98, p = 0.520). Survival curves demonstrated that 75% of graft failures occurred by 6 months after surgery, the rest occurring between 6 and 12 months postoperatively. Larger perforations encompassing more than or equal to 50% of the TM had lower success rates (HR 1.50, CI 1.02-2.21, p = 0.041) than smaller perforations encompassing less than 50% of the TM. Age was not correlated with success (HR 0.98, CI 0.93-1.03, p = 0.390).

CONCLUSION

This study found that non-autologous collagen grafts provide equivalent rates of healing when compared with autologous tissue in primary pediatric tympanoplasty. In addition to the potential for reduced operative time and donor site morbidity, these materials provide a viable graft alternative in fascia-depleted ears.Level of Evidence: Level 4.

Human-derived acellular dermal matrix may be an alternative to autologous grafts in tympanic membrane reconstruction: systematic review and meta-analysis

Background

Human-derived acellular dermal matrix (ADM) has been widely used as an effective alternative to autologous grafts in tympanoplasty. However, evidence of ADM as an alternative to autologous grafts in the repair of tympanic membrane (TM) perforation still lacks adequate empirical evidence.

Objectives

To determine the clinical safety and efficacy of human-derived ADM as TM graft material for tympanoplasty.

Data sources

The PubMed, EMBASE, Cochrane Library, EBSCO, Ovid, Scopus, and Web of Science databases and reference lists of the retrieved articles were searched, with no language restriction.

Selection criteria

All randomized controlled trials and retrospective cohort studies that compared the use of human-derived ADM and autologous grafts in tympanoplasty for TM perforation were included.

Data collection and analysis

Two review authors independently assessed risk of bias in the included studies and extracted data. The pooled results for continuous data were reported as a mean difference (MD) and 95% confidence intervals (CI). For dichotomous data, odds risk (OR) with 95% CI was used. ChI² statistic and Galbraith plots were used to assess the heterogeneity. Publication bias was assessed with a funnel plot and Egger’s test.

Main results

Five retrospective cohort studies and four randomized controlled studies with a total of 610 participants were included in the meta-analysis. No significant differences in graft success (OR: 0.71 [0.39, 1.29], p = 0.26), air-bone gap (ABG) reduction (MD: − 0.59 [− 3.81, 1.19], p = 0.51), or complications (OR: 1.23 [0.07, 20.64], p = 0.89) were found between the ADM group and autologous graft group. The use of ADM significantly shortened tympanoplasty surgery time (MD: − 16.14 [− 21.22, − 11.07], p < 0.00001) and reduced postoperative pain (MD: − 2.57 [− 3.57, − 1.58], p < 0.00001) compared with the autologous graft group.

Conclusion

Human-derived ADM might be an effective alternative to autologous grafts for tympanoplasty. However, some of the studies that were included in the present meta-analysis had rather low methodological quality, and more adequately designed clinical trials should be performed in the future.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40463-021-00518-w.

Comparison of type I tympanoplasty with acellular dermal allograft and cartilage perichondrium

Background: Acellular dermal allograft (AlloDerm) and cartilage perichondrium are two common materials used for repair of tympanic membrane perforations (TMPs). To date, comparative evaluations of their efficacy have rarely been reported. Aim/objectives: To compare anatomical and audiological outcomes between AlloDerm and cartilage perichondrium in type I tympanoplasty. Methods: A total of 61 patients of TMP were studied. In total, 27 patients (Group 1) underwent AlloDerm myringoplasty, and the remaining 34 patients (Group 2) underwent perichondrium myringoplasty. Operating time, closure rate and hearing gain were compared between Groups 1 and 2. Results: Successful closure rates at 6-month follow-up were 88.9% (Group 1) and 82.4% (group 2). The average improvement of air-bone gap (ABG) was 13.5 ± 11.8 dB for Group 1 and 13.1 ± 13.1 dB for Group 2. The difference in between preoperative and 6 months postoperative ABG values was statistically significant (p < .001). Conclusions and significance: Success rates and improvement of hearing level were similar for the AlloDerm (Group 1) and the cartilage perichondrium (Group 2) groups. However, AlloDerm requires shorter operative time and avoids the incisions in the harvest of allografts. Our results suggest that AlloDerm can be recommended as an attractive alternative to cartilage grafts.

Platelet-Rich Plasma Fat Graft versus Cartilage Perichondrium for Repair of Medium-Size Tympanic Membrane Perforations

OBJECTIVES

To compare clinical and audiologic outcomes among patients who underwent myringoplasty with fat graft enriched with platelet-rich plasma and cartilage perichondrium graft.

STUDY DESIGN

Prospective randomized controlled study.

SETTING

Department of Otolaryngology-Head and Neck Surgery, Tanta University, Egypt.

SUBJECTS AND METHODS

The study comprised 50 patients who had tympanic membrane perforation of medium size (25%-50% of its surface area) without evidence of active otitis media or ossicular abnormalities and who had surgery between December 2016 and December 2017. Patients randomly underwent myringoplasty with fat graft enriched with platelet-rich plasma (group 1) or cartilage perichondrium graft (group 2).

RESULTS

Twenty-five patients were included in each group. Rates of successful closure at 3-month follow-up were 88% (group 1) and 92% (group 2). The mean overall improvement in pure tone average was 18.08 dB (95% CI, 16.9-19.25) for group 1 and 18.24 dB (95% CI, 16.94-19.53) for group 2.

CONCLUSION

Fat graft enriched with platelet-rich plasma can be recommended as an alternative choice for first-line treatment of medium-size central perforations of the tympanic membrane, with healing and hearing results comparable to those of conventional cartilage perichondrium myringoplasty.

Mesenchymal stem cell-laden hybrid scaffold for regenerating subacute tympanic membrane perforation

Tympanic membrane (TM) perforation is one of the most common otology complications. To date, there has not been reported TM regeneration using bioprinted scaffold. The purpose of this study was to evaluate the efficacy and feasibility of bioprinted polycaprolactone/collagen/alginate-mesenchymal stem cell (PCAMSC) scaffolds for the regeneration of subacute TM perforation. Sprague-Dawley rats were used in an animal model of subacute TM perforation. In the experimental group (n=7), bioprinted 3D PCAMSC scaffold was placed on the perforation. The control group (n=7) were treated with polycaprolactone/collagen/alginate (PCA) scaffold. Healing time, acoustic-mechanical properties, and morphological analysis were performed by otoendoscopy, auditory brainstem response (ABR), single-point laser doppler vibrometer (LDV), optical coherence tomography (OCT), and light microscopic evaluation. The closure of the TM perforation was achieved in 100% of the experimental group vs. 72% of the control group, and this difference was statistically significant (p<0.05). The ABR threshold at all frequencies of the experimental group was recovered to the normal level compared to the control group. TM vibration velocity in the experimental group recovered similar to the normal control level. The difference are very small and they are not statistically significant below 1kHz (p=0.074). By OCT and light microscopic examination, regenerated TM of the experimental group showed thickened fibrous and mucosal layer. In contrast, the control group showed well regenerated but less thickened than experimental group. From these results, the cell-laden PCAMSC scaffold offers a significant advantage in the TM regeneration in a rat subacute TM perforation model. It may offer attractive opportunities in the conservative clinical treatment.

Total tympanic membrane reconstruction: AlloDerm versus temporalis fascia

BACKGROUND AND OBJECTIVE: Patients who require surgery for chronic otitis media with perforation and cholesteatoma frequently provide no residual tympanic membrane that is usable in grafting procedures. A novel technique of total tympanic membrane reconstruction (TTMR) is described that maximizes perforation closure rate in these situations while minimizing mucosalization, incomplete healing, and anterior blunting. The specific aim of this report is to assess the safety and efficacy of TTMR and to compare the results obtained with AlloDerm compared with temporalis fascia as a grafting material.

METHODS: The records of 50 patients operated within the years 1999 and the 2004 were reviewed. TTMR with intact canal wall was performed in all cases. Both clinical and audiometric data were analyzed.

RESULTS: Overall perforation closure rate was 92%. There was no statistical significance in closure rate when grafting with AlloDerm versus temporalis fascia. A statistically significant shortened healing time was observed with AlloDerm grafting.

CONCLUSIONS: TTMR is a highly effective and safe technique.

Porcine small intestinal submucosa (SIS) myringoplasty in children: A randomized controlled study

INTRODUCTION

A novel bioactive material for tissue graft, derived from porcine small intestinal mucosa (SIS) has been marketed. This material promotes early vessel growth, provides scaffolding for the remodeling tissues, and is inexpensive and ready-to-use. We evaluated efficacy, safety, and surgery time of SIS myringoplasty, in comparison with autologous temporalis fascia (PTF) repair in children in a prospective, two-group (SIS and PTF) randomized, blinded study at a tertiary-care pediatric institution.

MATERIALS AND METHODS

404 children with tympanic membrane (TM) repair were randomly assigned to receive SIS or PTF myringoplasty. Primary outcome was the healing of the TM at 6 months. Secondary outcomes were surgical time, and adverse events. Long-term follow-up ranging from 11 to 2 years was obtained in all enrolled children. Audiometric tests as pure-tone thresholds were applied in all patients. The Fisher's exact test and the Kriskal-Wallis test were applied for statistical analysis.

RESULTS AND DISCUSSIONS

Four-hundred-thirty-two TM perforations were treated, 217 in the SIS and 215 in the PTF groups. There were 209 stable TM closures in the SIS (96.3%) and 204 (94.8%) in the PTF arm. This difference was not statistically significant (odds ratio=0.4, 95%; confidence interval=0.12-1.41). SIS myringoplasty yielded reduced surgical time. No adverse reaction to SIS was encountered. Audiometric tests revealed no statistically significant difference in the two groups.

CONCLUSIONS

SIS myringoplasty is a safe and effective method for TM closure in children with reduced surgical time, as compared to PTF.

Animal models of chronic tympanic membrane perforation: a 'time-out' to review evidence and standardize design

OBJECTIVE

To review the literature on techniques for creation of chronic tympanic membrane perforations (TMP) in animal models. Establishing such models in a laboratory setting will have value if they replicate many of the properties of the human clinical condition and can thus be used for investigation of novel grafting materials or other interventions.

METHODS

A literature search of the PubMed database (1950-August 2014) was performed. The search included all English-language literature published attempts on chronic or delayed TMP in animal models. Studies of non English-language or acute TMP were excluded.

RESULTS

Thirty-seven studies were identified. Various methods to create TMP in animals have been used including infolding technique, thermal injury, re-myringotomy, and topical agents including chemicals and growth factor receptor inhibitors. The most common type of animal utilized was chinchilla, followed by rat and guinea pig. Twenty three of the 37 studies reported success in achieving chronic TMP animal model while 14 studies solely delayed the healing of TMP. Numerous experimental limitations were identified including TMP patency duration of <8 weeks, lack of documentation of total number of animals attempted and absence of proof for chronicity with otoscopic and histologic evidence.

CONCLUSION

The existing literature demonstrates the need for an ideal chronic TMP animal model to allow the development of new treatments and evaluate the risk of their clinical application. Various identified techniques seem promising, however, a need was identified for standardization of experimental design and evidence to address multiple limitations.

Repair of tympanic membrane perforation using novel adjuvant therapies: a contemporary review of experimental and tissue engineering studies

OBJECTIVE

To perform a contemporary review of experimental studies to describe the effects of various novel adjuvant therapies in enhancing tympanic membrane (TM) perforation healing.

METHODS

A PubMed search for articles from January 2000 to June 2012 related to TM perforation, along with the references of those articles, was performed. Inclusion and exclusion criteria were applied to all experimental studies assessing adjuvant therapies to TM healing.

RESULTS

Many studies have assessed the efficacy of biomolecules or growth factors, such as epidermal growth factors and basic fibroblast growth factors, in TM regeneration with significant success. More recent strategies in TM tissue engineering have involved utilizing bioengineered scaffold materials, such as silk fibroin, chitosan, calcium alginate, and decellularized extracellular matrices. Most scaffold materials demonstrated biocompatibility and faster TM perforation healing rates.

CONCLUSION

Although several studies have demonstrated promising results, many questions still remain, such as the adequacy of animal models and long-term biocompatibility of adjuvant materials. As well, further studies comparing various adjuvant substances and bioscaffolds are required prior to clinical application.

Tissue engineering of the tympanic membrane

Tympanic membrane (TM) perforations are common, with current treatments for chronic perforations involving surgery, using various graft materials, from autologous cartilage or fascia through to paper patch. Recent research developments in this field have begun applying the principles of tissue engineering, with appropriate scaffolds, cells, and bioactive molecules (BMs). This has revolutionized the therapeutic approach due to the availability of a wide range of materials with appropriate compatibility and mechanical properties to regenerate the membrane acoustics and may also represent a paradigm shift in the management of TM perforations in an outpatient setting without surgery. However, many factors need to be considered in the fabrication of a bioengineered TM. This review discusses the issues associated with current treatment and examines TM wound healing relevant to the construction of a bioengineered TM. It also describes the tissue-engineering approach to TM regeneration by summarizing currently used scaffolds, BMs, and cells in TM wound healing. Finally, it considers the design of scaffolds, delivery of BMs, and cell engraftment toward potential clinical application.

Middle ear of human and pig: a comparison of structures and mechanics

INTRODUCTION

Animal studies are an essential method to evaluate implants for the middle ear prior to clinical studies. New Zealand rabbits, guinea pigs and chinchillas are, among other small mammals, well established animal models, but their auditory system is significantly smaller compared to human. Hence, the suitability of the domestic pig (sus scrofa domesticus) as a new animal model for research on the middle ear (ME), that would match the human in size, was investigated.

METHODS

Thirty halved pig heads were obtained from the butcher and each middle ear was dissected. Using a digital light microscope, several anatomical magnitudes were determined for 24 specimens, namely the planar projected area of the tympanic membrane (TM), in relation to the stapes footplate as well as the dimensions and weight of the ossicles, in order to determine the effective lever ratios. Using normal and micro computed tomography (CT), six porcine temporal bones were scanned and the geometric data obtained were transferred into a finite element model (FEM) simulation of the porcine middle ear. The transfer function was determined and compared to those from humans determined by measurements and simulations, respectively.

RESULTS

The anatomy investigated presented itself as highly comparable to that of the human. Differing from literature, no fourth ossicle could be found. The porcine dimensions and lever ratios determined match the humans far better than those of all established animal models. The obtained transfer function was congruent to the human one. This underlines the suitability of the pig as an animal model for middle ear implants.

Sutureless tympanoplasty using acellular dermis

OBJECTIVE

A prospective randomized unblinded controlled trial was conducted by comparing acellular dermis with temporalis fascia as graft materials in tympanoplasty (type 1) in terms of operative time, postoperative pain, graft success rate, and audiologic outcome.

STUDY DESIGN

Forty-two patients with (inactive) chronic suppurative otitis media of tubotympanic type were randomized, matched, and divided equally into 2 groups of 21 each. One group underwent tympanoplasty (type 1) via transcanal route using temporalis fascia graft and the other using acellular dermis. Both groups were compared for operative time, postoperative pain, graft success rate, and audiologic improvement in hearing.

RESULTS

There was a statistically significant reduction in operative time (P < .05) and postoperative pain (P < .05) in the acellular dermis group. However, there was no statistical difference in graft success rate (P > .05) and hearing improvement (P > .05) between both the groups.

CONCLUSION

Results of tympanoplasty using acellular dermis as graft material are comparable to that using temporalis fascia in terms of graft uptake and hearing improvement. However, tympanoplasty using acellular dermis has the advantage of shorter operative time and lesser postoperative pain.

Acellular porcine intestinal submucosa as fascial graft in an animal model: Applications for revision tympanoplasty

OBJECTIVE: To demonstrate regeneration of muscle fascia appropriate for future harvest with the use of acellular porcine intestinal submucosa in a rat model.

STUDY DESIGN: Animal cohort study.

SETTING: Tertiary care academic medical center.

SUBJECTS AND METHODS: Sixteen male Sprague-Dawley rats underwent excision of rectus abdominis muscle fascia. A sheet of acellular porcine intestinal submucosa was placed in the fascia harvest defect. Graft and underlying muscle were harvested at three-, six-, and nine-week intervals. Histologic examination, including immunohistology for anti-von Willebrand factor, was performed at each timepoint. Additional selected specimens were subjected to latex vascular perfusion casts to examine vessel growth patterns within the graft.

RESULTS: Gross examination revealed a new tissue plane, indistinguishable from surrounding native fascia. Histology revealed an initial inflammatory response within the graft. Progressive influx of native tissue was noted over successive timepoints. Via collagen-specific staining, we noted progressive reorganization and maturation of the graft collagen matrix. At the final nine-week time point, a new loose connective tissue plane was reestablished between the graft and underlying muscle. Immunohistochemistry and latex perfusion both demonstrate an initial development of small capillaries that progresses over time to greater organization and arteriole formation.

CONCLUSION: Fascia regeneration may be possible with use of an acellular porcine intestinal submucosa graft in an animal model. Future studies may prove beneficial in restoring fascia in humans. Implications for potential advantages in tympanoplasty are discussed.

© 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Repair of the tympanic membrane with urinary bladder matrix

OBJECTIVES/HYPOTHESIS

To test urinary bladder matrix (UBM) as a potential treatment for tympanic membrane (TM) healing and regeneration.

STUDY DESIGN

This prospective pilot study was designed to provide both qualitative and semiquantitative assessment of temporal and spatial healing events in the chinchilla model of chronic TM perforations with and without UBM patching.

METHODS

Bilateral myringotomies were performed and repeated as necessary to create subtotal perforations over an 8-week period. Myringoplasty was then performed, with left TMs serving as controls and right TMs receiving UBM patches. TMs were excised at 4 weeks, 8 weeks, and 12 weeks. Fixed tissue samples were characterized for gross morphology, then processed for microscopic evaluation.

RESULTS

Chronic perforations were maintained with one or more repeated myringotomies. Although both control and patched TMs were thicker than native tissue, patched TMs were transparent and uniform in thickness without any inclusions. UBM patches were readily degraded and replaced by newly deposited and organized host tissue that recapitulated the native TM layers.

CONCLUSIONS

UBM scaffolds were an effective biological scaffold for TM closure and tissue remodeling, leading to thicker than normal anatomy but otherwise normal morphology. Future studies are required to determine functional and temporal outcomes as well as alternative patch orientations. The results show particular promise as a superior alternative means of reconstructing not only chronic TM perforations but also dimeric TMs associated with retraction pockets and atelectasis. Laryngoscope, 2009.

Reconstruction of a recurrent first dorsal web space defect using acellular dermis

Oncologic defects of the hand can be problematic for the reconstructive surgeon. These defects may require a delay in definitive coverage until clear margins of resection can be obtained, which can result in a prolonged period of painful dressing changes and increased risk of soft-tissue infection. In addition, reconstructive options for oncologic defects are often limited to skin grafting, which can yield functional deficits secondary to contracted healing. Currently, there is no definitive method for preventing skin graft contracture; however, acellular dermis has been proposed as a biomechanical scaffold to enhance subsequent skin graft healing and slow this functionally debilitating process. Here, we present a patient with recurrent melanoma of the first dorsal web space. After re-resection of the melanoma, the 11 cm x 5 cm defect was reconstructed using acellular dermis as temporary coverage to allow ample time for permanent section results. Ten days later, after confirming negative margins of resection, a split-thickness skin graft (STSG) was applied over the vascularized neo-dermis. Follow-up clinical examination and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaires were used to assess outcome. At 7 months, the patient had no recurrence of melanoma and a DASH functional reduction of only 6.9%. After approximately 18 months, the patient's wounds had healed with excellent cosmetic and functional results, without any evidence of a web space contracture. These observations suggest that acellular dermis is a useful adjunct for wound coverage of the hand, particularly in areas of functional importance, such as the first dorsal web space.

Suitability of formaldehyde-treated acellular dermis for tympanic membrane repair in chinchillas

HYPOTHESIS

Formalin-fixed acellular dermis (AlloDerm; LifeCell Corporation, Branchberg, NJ, USA) is safe and efficacious for tympanoplasty in the chinchilla model as compared with the established technique of nonfixed acellular dermis tympanoplasty.

BACKGROUND

Temporalis fascia autografts have been shown safe and effective in the treatment of near-total tympanic membrane (TM) perforations. The formalin-fixation technique first described by Perkins allows the autologous fascia graft to be shaped to more closely resemble the natural TM and has been successful but somewhat cumbersome. The use of acellular dermis as a fascia substitute has also been shown safe and effective in closing smaller perforations. We sought to determine whether formalin-fixed acellular dermis is as safe and useful as nonfixed acellular dermis for TM perforation repair by examining inflammation and tissue effects in a well-established animal model of perforation.

METHODS

Fifteen adult chinchillas underwent creation of 2-mm central perforations created using a Coherent CO2 laser. Each chinchilla underwent an immediate formalin-fixed acellular dermis repair in one ear and an unfixed acellular dermis repair in the other ear as a control. The chinchillas were randomized with regard to the repair applied to each ear. After 6 weeks of observation, the animals were killed by using sodium pentobarbital (dose, 150 mg/kg). The TMs were otomicroscopically examined for tissue reaction and repair success by a blinded observer. An estimate of residual perforation, if any, was made at that time. The TMs were then harvested and examined histopathologically by a blinded veterinary pathologist.

RESULTS

Thirteen chinchillas survived to the evaluation endpoint. There were no significant differences in inflammation, fibrosis, and cellular ingrowth between the 2 groups, although there was a trend toward less inflammation in the formalin-fixed ears. Effusions were present in 15% of non-formalin-fixed ears. Adhesions were present in 15% of non-formalin-fixed ears and 8% of the formalin-fixed ears. A TM cholesteatoma was observed in one non-formalin-fixed ear. The TMs were completely healed in 11 (85%) of 13 TMs in each group.

CONCLUSION

Formalin-fixed acellular dermis was as safe and efficacious as nonfixed acellular dermis in the repair of TM perforations in a chinchilla model. No adverse tissue effects related to formalin treatment were observed.

Lateral graft type 1 tympanoplasty using AlloDerm for tympanic membrane reconstruction in children

OBJECTIVES

To describe the lateral graft type 1 tympanoplasty technique using AlloDerm for tympanic membrane reconstruction in children and to compare its surgical and audiometric outcomes with the traditional underlay type 1 tympanoplasty.

METHODS

The records of 34 consecutive children undergoing type 1 tympanoplasty between 2004 and 2005 were reviewed; 18 received lateral graft tympanoplasty with AlloDerm and 16 received underlay tympanoplasty (8 AlloDerm and 8 temporalis fascia). Pre- and post-surgical audiograms, speech reception threshold, closure rate and complication rate were evaluated using one-way and repeated measures ANOVAs.

RESULTS

Children who underwent lateral graft type 1 tympanoplasty pre-operatively had larger tympanic membrane perforations, worse pure tone averages, air bone gaps and speech reception thresholds as compared with children undergoing underlay type 1 tympanoplasty (P<0.001). Pure tone averages and air bone gaps improved significantly with surgery in both lateral and underlay type 1 tympanoplasty groups (P<0.05), with both groups achieving comparable postoperative audiometric outcomes (P>0.01). The lateral graft group demonstrated a higher perforation closure rate (94%) as compared with both underlay groups (88%). Complication rates were virtually non-existent.

CONCLUSIONS

Despite larger perforations and worse pre-operative audiometric scores, children who underwent lateral graft type 1 tympanoplasty achieved comparable postoperative audiometric results and perforation closure rates as compared with children who underwent underlay type 1 tympanoplasty. Results suggest that lateral graft type 1 tympanoplasty using AlloDerm is effective for tympanic membrane reconstruction in children and should be used when temporalis fascia is not available or the extent of the perforation limits its use.

Role of acellular dermal matrix allograft in minimal invasive coverage of deep burn wound with bone exposed--case report and histological evaluation

A sandwich graft was applied to the debrided cortical bone layer of the tibia in the case of a 72-year-old male patient with full-thickness necrotic burn injury. The combined graft consisted of a dermal template material and autologous split thickness skin graft. After application, the graft was found totally accepted and provided good functionality with acceptable appearance. Histopathologic evaluation revealed a complete take with revascularisation of the implant. Supporting lamellar bony trabecules were also seen in the deep dermal dermis representing a connection to the underlying bone. The use of the dermal matrix in deep burn exposing the bone provides a satisfactory functional result and good cosmetic appearance.

Implant breast reconstruction using acellular dermal matrix

Thirteen breast reconstructions in 11 patients, averaging 58 years of age, underwent mastectomies. The technique uses a saline implant either totally or partially covered with a human acellular dermal matrix. The mean postoperative follow-up time was 14 months. Ninety percent of the patients were considered high risk; the thickness of the human acellular dermal matrix was an average of 1.3 mm, with an average area per breast of 121 cm. There were 12 successful breast reconstructions (92%) that provided stability, increased soft tissue padding, which allowed a greater resemblance to normal breast shape and decreased rippling and implant visibility. The graft was used in an onlay fashion or as an extension of the pectoralis major muscle that covers the implant. A representative histologic cross-section of well-integrated human acellular dermal matrix is presented. The use of a human acellular dermal matrix in breast reconstruction is an alternative protocol in high-risk patients, resulting in a minimal increase in operative time and a decrease in morbidity compared with more extensive procedures.

Acellular allograft dermal matrix for tympanoplasty

PURPOSE OF REVIEW

Reconstruction of the tympanic membrane is a common procedure in otology today. Many different materials have been used for this purpose, including a wide array of autologous tissues. This article focuses on the use of human acellular allograft dermal matrix (AlloDerm, LifeCell Corporation, Branchburg, New Jersey) in tympanoplasty.

RECENT FINDINGS

The choice of graft materials has expanded to include human dermal allograft tissue. Recent reports show promising results for AlloDerm reconstruction of the tympanic membrane, including animal experiments and in humans.

SUMMARY

AlloDerm has become an acceptable alternative to the use of autologous tissues in tympanic membrane surgery, particularly in type I tympanoplasty. This paper discusses the recent literature on the topic, outlines the authors' experience with the use of AlloDerm, and describes the authors' operative technique.

Use of AlloDerm in Type I Tympanoplasty: A Comparison with Native Tissue Grafts

OBJECTIVES

AlloDerm, an acellular human dermis allograft, has been shown to be an effective option as a tympanic membrane (TM) graft in animals and humans and has several potential advantages, including eliminating donor site morbidity, reducing operative time, and preserving native tissues for later use. We compared AlloDerm and native tissue grafts in type I tympanoplasty with regard to operative time, graft success rate, and audiologic outcome.

STUDY DESIGN

A retrospective chart review of tympanoplasties performed at a major tertiary referral hospital over a 31 month period, starting with the first use of AlloDerm for TM grafting at this institution.

METHODS

The medical charts of all patients undergoing tympanoplasty were reviewed. Only those patients undergoing type I tympanoplasty without mastoidectomy or ossicular chain reconstruction were included. These 114 patients (25 AlloDerm, 56 fascia reconstruction, and 33 fascia plus cartilage reconstruction) were compared for operative time, success rate of the graft, and change in audiologic outcome.

RESULTS

There was a statistically significant reduction in operative time in the AlloDerm group when controlled for surgeon and choice of approach. All groups showed no statistically significant difference in the success rate of the graft and closure of audiologic air-bone gap, regardless of graft material used.

CONCLUSIONS

AlloDerm is an effective TM graft when used in type I tympanoplasty. It is as effective as native tissues in closing the air-bone gap on audiogram as well as in graft success rate. AlloDerm may also significantly reduce operative time, depending on the surgeon's technique.

[An improved animal model for chronic perforation of the tympanic membrane]

BACKGROUND

An inexpensive and valid animal model of chronic tympanic membrane perforation is needed.

METHOD

Twelve male rats were selected for different surgical procedures (subtotal tympanic membrane perforation with local microflaps, re-perforation without flaps, partial excision of the handle of malleus). The inhibition of spontaneous healing was accomplished by the application of prednisolon or mitomycin directly onto the tympanic membrane.

RESULTS

Only by additional partial excision of the handle of malleus followed by local application of mitomycin were we able to achieve a persistent tympanic membrane perforation.

CONCLUSION

Chronic tympanic membrane perforation using this procedure may be useful in further investigations of the medical impact of tympanic membrane healing.