Quality Of Margins Research Articles

A stylized model of overrepresentation and quality in the Congress

Traditionally, overrepresentation has been used to explain the distribution of benefits across jurisdictions, leaving aside quality components. We present a model that demonstrates that in the dispute of limited federal benefits, although quantity is important, at the margin quality matters.

Number of fragments, margin status and thermal artifacts of conized specimens from LLETZ surgery to treat cervical intraepithelial neoplasia.

Large loop excision of the transformation zone (LLETZ) is a nontraumatic cut and coagulation method with several advantages, but it induces thermal artifacts in the cut region. The aim here was to assess the correlations of age, number of fragments, lesion grade and degree of thermal artifacts with margin quality in conized specimens from LLETZ for cervical intraepithelial neoplasia (CIN). Cross-sectional study at Universidade Federal de São Paulo (Unifesp). The records and histopathology findings of 118 women who underwent LLETZ between 1999 and 2007 were reviewed. Age, number of fragments, lesion grade, degree of thermal artifacts and margin quality were assessed. The patients' mean age was 27.14 years; 63.6% had been diagnosed with CIN II and 36.4% with CIN III. The lesion was removed as a single fragment in 79.6% of the cases. The margins were free from intraepithelial neoplasia in 85.6% and compromised in the endocervical margin in 6.8%. Fragment damage due to artifacts occurred in 2.5%. Severe artifacts occurred in 22.8%. Women aged 30 years or over presented more cases of CIN III (P < 0.0004). Neoplastic compromising of surgical margins and severe artifacts occurred more often in cases in which two or more fragments were removed, and in patients aged 30 years or over. CIN III in women aged 30 or over, when removed in two or more fragments during LLETZ, presented a greater number of compromised margins and greater severity of thermal artifacts.

COMMENTARY. The Effect of Ultrasonic Instruments on the Quality of Preparation Margins and Bonding to Dentin1

COMMENTARY. The Effect of Ultrasonic Instruments on the Quality of Preparation Margins and Bonding to Dentin¹

The Effect of Ultrasonic Instruments on the Quality of Preparation Margins and Bonding to Dentin

Ultrasonic instruments have recently been developed for finishing crown preparations. They are successful in accessing difficult areas on the preparation margin, but their effects on the dentin surface and on bond strength are contradictory. The aim was to evaluate the condition of crown preparation margins finished using new ultrasonic instruments and to assess their effects on dentin bond strength. Characteristics of tooth surfaces prepared using two different ultrasonic protocols were compared; Perfect Margin Shoulder (PMS) (PMS 3, Satelec, Merignac, France) 1, 2, and 3 (complete finishing) versus PMS 1 and 2 (partial finishing). They were assessed using scanning electron microscopy (SEM) and surface roughness analysis. Bonding of composite resin to dentin surfaces prepared with the complete PMS kit was compared with dentin surfaces prepared with finishing diamond burs, using micro-tensile testing. SEM images revealed a clear difference between the two preparation sequences (PMS 1, 2 versus PMS 1, 2, and 3). Surfaces finished using the PMS tips 1, 2, and 3 appeared continuous, even, and smooth compared with PMS tips 1 and 2 only. The additional use of the PMS 3 uncoated tip enhanced smear layer removal. There was no significant difference when comparing the surface roughness obtained with the PMS 1, 2, and 3 protocol with the PMS 1 and 2 only (p > 0.05). Micro-tensile bond strength was not significantly different between the surfaces prepared with the ultrasonic instruments and the surfaces prepared with the diamond burs (p > 0.05). The use of the complete PMS finishing kit (PMS 1, 2, and 3) produced better quality finishing lines than PMS 1 and 2. The use of ultrasonic instruments to prepare dentin resulted in comparable bond strengths to the use of diamond burs. The extremely precise preparation margin possible with ultrasonic instruments improves the quality and accuracy of crown preparations, which may lead to better impressions and closer adaptation of restorations. The complete set of three Perfect Margin Shoulder instruments is recommended, which can produce comparable bond strengths to preparations with rotary instruments.

Survival and prognostic factors in chondrosarcoma

Background and purpose There have been few long-term studies on the outcome of chondrosarcoma and the findings regarding prognostic factors are controversial. We examined a homogeneous group of patients with primary central chondrosarcoma of bone who were treated according to a uniform surgical protocol at our institution, in order to determine the factors that influence survival and identify potential improvements to our therapeutic algorithm.Patients and methods We performed a retrospective analysis of 115 patients with primary central chondrosarcoma of bone who presented with localized disease and who had a minimum follow-up of 5 years after diagnosis. 68 tumors were localized in the extremities and 47 in the axial skeleton or pelvis. 59 patients had a high-grade (II and III) and 56 a low-grade (I) tumor. 94 patients underwent surgical resection with adequate (wide or radical) margins, while 21 patients had inadequate (marginal or intralesional) margins.Results Tumor grade and localization were found to be statistically significant independent predictors of disease-related deaths in multivariate analysis. The quality of surgical margins did not influence survival. The AJCC staging system was able to predict prognosis in patients with chondrosarcoma of the extremities, but not in those with tumors of the axial skeleton and pelvis. Long-term survival after secondary metastatic disease was only observed when metastases were resected with wide margins. Patients with metastases who received further treatment with conventional chemotherapy, radiotherapy, and/or further surgery had significantly better survival compared to those who received best supportive care.Interpretation The outcome in patients with primary central chondrosarcoma of bone who present with localized disease is mostly affected by tumor-related parameters.

Randomized Clinical Trial of Four Adhesion Strategies: 18-Month Results

With Institutional Review Board approval, 39 patients who needed restoration of noncarious cervical lesions (NCCLs) were enrolled in this study. A total of 125 NCCLs were selected and randomly assigned to four groups: 1) a three-step etch-and-rinse adhesive, Adper Scotchbond Multi-Purpose (MP, 3M ESPE, St Paul, MN, USA); 2) a two-step etch-and-rinse adhesive, Adper Single Bond Plus (SB, 3M ESPE); 3) a two-step self-etch adhesive, Adper Scotchbond SE (SE, 3M ESPE); and 4) a one-step self-etch adhesive, Adper Easy Bond (EB, 3M ESPE). A nanofilled composite resin was used for all restorations. Restorations were evaluated at six months and 18 months using modified U.S. Public Health Service (USPHS) parameters. At six months after initial placement, 107 restorations (85.6% recall rate) were evaluated. At 18 months, 94 restorations (75.2% recall rate) were available for evaluation. The 6 mo/18 mo overall retention rates (%) were 100/90.9 for MP; 100/91.7 for SB; 100/90.9 for SE; and 96.4/92.3 for EB with no statistical difference between any pair of groups at each recall. Sensitivity to air decreased significantly for all adhesives from the preoperative to the postoperative stage and was stable thereafter. Interfacial staining did not change statistically from baseline to six months; however, interfacial staining at the enamel margins was statistically worse at 18 months than at baseline for the two self-etch adhesives EB and SE. Marginal adaptation was statistically worse at 18 months compared with baseline only for EB. This tendency was already significant at the six-month recall. Although 18-month retention was similar for the different adhesion strategies, enamel marginal deficiencies were more prevalent for the self-etch adhesives.

Retroperitoneal Sarcoma: Is It Time to Change the Surgical Policy?

Background. Complete tumor resection is the mainstay of treatment for retroperitoneal sarcoma (RPS), but the size and quality of surgical margins for radical resection in RPS are unknown. They are believed to be pushing tumors, but recently, aggressive surgical policies leading to multivisceral resection have seemed to suggest better local control compared with simple tumor resection. We analyzed a single-institution series of RPS to provide information useful to surgical decision-making. Methods. From 1996 to 2008, 77 patients referred to our institution underwent surgery for primary RPS. Thirty tumors were classified as liposarcoma, and 20 as leiomyosarcoma. Potential prognostic factors were tested retrospectively. Number and pathologic status of resected organs were assessed. Results. 151 organs were resected. Ninety-two were involved by the tumor (60.9%). Liposarcoma involved 48 of 77 organs resected for this histotype (62.3%). Infiltrative pattern was observed in 39/92 organs, and expansive pattern in 53/92 viscera. The infiltrative pattern was more often observed in leiomyosarcoma and non-lipogenic tumors. The expansive pattern was more often observed in liposarcoma. Psoas was the organ most often involved by infiltrative pattern (12/14); the kidney was the organ most often involved by expansive pattern (19/28). 80% of patients had at least one viscera infiltrated by the tumor. Conclusions. This series, in which an aggressive surgical policy was adopted along with extensive pathologic sampling, shows that RPS has a high rate of viscera infiltration. This growth pattern is characteristic of well-differentiated liposarcoma too. These pathologic data should be considered when planning surgical strategy.

Retroperitoneal Sarcoma: Is It Time to Change the Surgical Policy?

Complete tumor resection is the mainstay of treatment for retroperitoneal sarcoma (RPS), but the size and quality of surgical margins for radical resection in RPS are unknown. They are believed to be pushing tumors, but recently, aggressive surgical policies leading to multivisceral resection have seemed to suggest better local control compared with simple tumor resection. We analyzed a single-institution series of RPS to provide information useful to surgical decision-making. From 1996 to 2008, 77 patients referred to our institution underwent surgery for primary RPS. Thirty tumors were classified as liposarcoma, and 20 as leiomyosarcoma. Potential prognostic factors were tested retrospectively. Number and pathologic status of resected organs were assessed. 151 organs were resected. Ninety-two were involved by the tumor (60.9%). Liposarcoma involved 48 of 77 organs resected for this histotype (62.3%). Infiltrative pattern was observed in 39/92 organs, and expansive pattern in 53/92 viscera. The infiltrative pattern was more often observed in leiomyosarcoma and non-lipogenic tumors. The expansive pattern was more often observed in liposarcoma. Psoas was the organ most often involved by infiltrative pattern (12/14); the kidney was the organ most often involved by expansive pattern (19/28). 80% of patients had at least one viscera infiltrated by the tumor. This series, in which an aggressive surgical policy was adopted along with extensive pathologic sampling, shows that RPS has a high rate of viscera infiltration. This growth pattern is characteristic of well-differentiated liposarcoma too. These pathologic data should be considered when planning surgical strategy.

Ultrasound-guided breast-sparing surgery to improve cosmetic outcomes and quality of life. A prospective multicentre randomised controlled clinical trial comparing ultrasound-guided surgery to traditional palpation-guided surgery (COBALT trial)

BackgroundBreast-conserving surgery for breast cancer was developed as a method to preserve healthy breast tissue, thereby improving cosmetic outcomes. Thus far, the primary aim of breast-conserving surgery has been the achievement of tumour-free resection margins and prevention of local recurrence, whereas the cosmetic outcome has been considered less important. Large studies have reported poor cosmetic outcomes in 20-40% of patients after breast-conserving surgery, with the volume of the resected breast tissue being the major determinant. There is clear evidence for the efficacy of ultrasonography in the resection of nonpalpable tumours. Surgical resection of palpable breast cancer is performed with guidance by intra-operative palpation. These palpation-guided excisions often result in an unnecessarily wide resection of adjacent healthy breast tissue, while the rate of tumour-involved resection margins is still high. It is hypothesised that the use of intra-operative ultrasonography in the excision of palpable breast cancer will improve the ability to spare healthy breast tissue while maintaining or even improving the oncological margin status. The aim of this study is to compare ultrasound-guided surgery for palpable tumours with the standard palpation-guided surgery in terms of the extent of healthy breast tissue resection, the percentage of tumour-free margins, cosmetic outcomes and quality of life.Methods/designIn this prospective multicentre randomised controlled clinical trial, 120 women who have been diagnosed with palpable early-stage (T1-2N0-1) primary invasive breast cancer and deemed suitable for breast-conserving surgery will be randomised between ultrasound-guided surgery and palpation-guided surgery. With this sample size, an expected 20% reduction of resected breast tissue and an 18% difference in tumour-free margins can be detected with a power of 80%. Secondary endpoints include cosmetic outcomes and quality of life. The rationale, study design and planned analyses are described.ConclusionThe COBALT trial is a prospective, multicentre, randomised controlled study to assess the efficacy of ultrasound-guided breast-conserving surgery in patients with palpable early-stage primary invasive breast cancer in terms of the sparing of breast tissue, oncological margin status, cosmetic outcomes and quality of life.Trial Registration NumberNetherlands Trial Register (NTR): NTR2579

Actualisation de la stratégie thérapeutique locorégionale dans les sarcomes des tissus mous et les tumeurs desmoïdes des membres

The treatment of soft tissue sarcomas of limbs should be discussed within an experienced multimodality team. Surgical resection remains the cornerstone of therapy for localized disease and achieves a five years overall survival around 75% and a local recurrence rate as low as 10% in the best series. In complex cases, neo-adjuvant treatments may be used such as systemic chemotherapy, isolated limb perfusion, or radiotherapy to achieve an optimal conservative approach. Molecular genetics of sarcomas and quality of margins are essential to guide diagnosis and therapeutic selection. In case of marginal or incomplete resection, a new enlarged surgical resection should always be discussed before administration of any adjuvant treatments. Many retrospective studies and two randomized studies (one of adjuvant brachytherapy and one of external beam radiotherapy) have shown that adjuvant radiotherapy after complete surgery significantly reduces the risk of local recurrence in extremity soft tissue sarcomas. A randomized study has compared pre- to postoperative radiotherapy. The results in terms of local control are similar in both arms. The risk of surgical complications is higher in the preoperative arm and the risk of late sequelae is higher in the postoperative arm. A randomized study within the French sarcoma group is ongoing evaluating the omission of postoperative radiotherapy in favourable cases. Presently, the role of systematic first-line invasive treatment (including surgery and/or radiotherapy) of desmoids is debated. It is becoming evident that up to 50% of patients with desmoids benefit from a front-line non-aggressive policy, because growth arrest is a common feature of this disease. Additional study of the molecular determinants of desmoid behaviour is needed to guide treatment.

Evaluation of the marginal integrity of ceramic copings with different marginal angles using two different CAD/CAM systems

Objectives To investigate and compare the marginal integrity of ceramic copings constructed with the CEREC3 and the EVEREST system employing three different margin angle designs and explore to what extent these CAD/CAM machines can produce acute marginal angles creating restorations with acceptable margins. Materials and methods Three brass models were prepared with a different marginal finish line, namely a 0° bevel (or 90° shoulder), a 30° bevel and a 60° bevel. Ten restorations were produced for each finishing line and CAD/CAM system, respectively. The copings were milled from lithium disilicate glass ceramic blocks (IPS e.max ® CAD). An impression was taken for each model to fabricate a series of 10 replica dies for each marginal design. Quantitative analysis of the margins of each coping was performed using digital photography and image analysis software. The marginal integrity of the restorations was evaluated by detecting and measuring any signs of marginal chipping and the Chipping Factor (CF) was calculated. Statistical analysis was performed using Univariate Analysis of Variance and multiple comparisons (Tukey HSD). Results The average Chipping Factor (CF) of the CEREC copings was: 2.8% for the 0° bevel angle, 3.5% for the 30° bevel angle and 10% for the 60° bevel angle. For the EVEREST copings the average CF was: 0.6% for the 0° bevel angle, 3.2% for the 30° bevel angle and 2.0% for the 60° bevel angle. Univariate Analysis of Variance and multiple comparisons showed that there was a statistically significant difference in the quality of margins between the two systems for the 0° and 60° bevel finishing line. Conclusions The results of this study indicated that the introduction of a marginal angle of the restoration increases the potential for marginal chipping. Different CAD/CAM systems which employ different milling processes produce restorations with different amount of marginal chipping, although this only became apparent for a marginal angle of a 60°.

Imaging findings of pancreatoblastoma in 4 children including a case of ectopic pancreatoblastoma

Pancreatoblastoma is a rare primary pancreatic neoplasm of children. The tumour may arise from any portion of the pancreas, but no tumour originating from ectopic pancreatic tissue has been reported in the English medical literature. We report the radiological findings of pancreatoblastoma in four children, including one tumour originating from the mesentery, to our knowledge, reported for the first time. Four children with pancreatoblastoma were identified at our hospital between 2000 and 2007. US and CT were performed in all children, with MR performed in two. Various CT and MRI features were evaluated including size, organ of origin, definition and quality of tumour margins, heterogeneity and attenuation of the mass, calcification, presence of ascites, adenopathy, metastases, and signal intensity on MR images. Complete excision was performed in all children. The diagnosis of pancreatoblastoma was confirmed with histopathological results. Our cases displayed some typical and atypical features of pancreatoblastoma. The findings of our series suggest that the majority of these tumours are large, heterogeneous and of low to intermediate signal intensity on T1-W images and high signal intensity on T2-W images. Calcifications were common on CT. All of the tumours had heterogeneous enhancement on CT and MR images. Pancreatoblastoma is a rare primary tumour of the pancreas. When a large mass is identified in the pancreas in children that is heterogeneous in nature with internal calcifications, the diagnosis should be considered.

Surgical Margins and Local Control in Resection of Sacral Chordomas

The treatment of choice in sacral chordoma is surgical resection, although the risk of local recurrence and metastasis remains high. The quality of surgical margins obtained at initial surgery is the primary factor to improve survival reducing the risk of local recurrence, but proximal sacral resections are associated with substantial perioperative morbidity. We considered survivorship related to local recurrence in terms of surgical margins, level of resection, and previous surgery. We retrospectively reviewed 56 patients with sacral chordomas treated with surgical resection. Thirty-seven were resected above S3 by a combined anterior and posterior approach and 19 at or below S3 by a posterior approach. Nine of these had had previous intralesional surgery elsewhere. The minimum followup was 3 years (mean, 9.5 years; range, 3-28 years). Overall survival was 97% at 5 years, 71% at 10 years, and 47% at 15 years. Survivorship to local recurrence was 65% at 5 years and 52% at 10 years. Thirty percent of patients developed metastases. Wide margins were associated with increased survivorship to local recurrence. We found no differences in local recurrence between wide and wide-contaminated margins (that is, if the tumor or its pseudocapsule was exposed intraoperatively, but further tissue was removed to achieve wide margins). Previous intralesional surgery was associated with an increased local recurrence rate. We observed no differences in the recurrence rate in resections above S3 or at and below S3. Surgical margins affect the risk of local recurrence. Previous intralesional surgery was associated with a higher rate of local recurrence. Intraoperative contamination did not affect the risk of local recurrence when wide margins were subsequently attained.

Quality of surgical margins and local recurrence in primary extremity soft tissue sarcoma (STS).

10068 Background: In previous studies, quality of margins after resection of primary STS of extremity was only defined by their size. Methods: We analyzed all patients (pts) with primary limbs STS addressed for surgery in our institution from 1997 to 2008 in a prospective data base. All histological specimens were reviewed and quality of margins prospectively evaluated. The minimum margin (in mm) and the type of surrounding tissue (muscle, aponevrosis, fat, periosteum) were registered on fixed specimen. The endpoints were mortality, local recurrence (LR) and distant metastasis analyzed by Cox multivariate models. Results: There were 450 pts: 50% were operated at first after pre-operative biopsy (Group A) and 50% had a second extended resection after unplanned surgery (Group B). 81% were deep. Mean tumor size was 12cm in group A and 7cm in group B (p<.0001). Grades were: 1 (21%), 2 (33%), 3 (47%). 99% had limb sparing surgery with 14% flap reconstruction. Margins (mm) were 0 in 14%, [0 – 1]: 28%, [1 – 5]: 37%, [5 – 10]: 11%, >10: 10%. Clear median minimum margin was 2mm (0.5 – 35). Tissue type varied according to width, with higher proportion of aponevrosis and periosteum below 2mm (61%) than above (29%) (p<.0001). In group B, residual tumor was found in 61% of pts. 36% of pts received chemotherapy (neo-adjuvant 88%, adjuvant 12%), 18% had neo-adjuvant isolated limb perfusion. 74% of pts received radiotherapy (post op 93%, pre op 6%) with a median dose of 50Gy (30 to 70Gy). Among pts who had neo adjuvant ILP/CT/RX, the mean% of viable cells was 36, 44 and 46 respectively. With a median follow up of 4.2 yrs, the 5-yr OS, LR and metastatic rates were 79%, 8% and 22% respectively. In the multivariate analysis, high grade (p<.0001) and large tumor size (p<.002) were the only predictive factors for shorter OS. Absence of clear margins (0mm) was significantly predictive of LR (p<.001). Conclusions: In this high risk series, a very low rate of local recurrence was observed despite a small median minimum margin. This suggests that the quality of margins should integrate the quality of the tissue involved. A planned extended surgery associated with combined treatments guarantees a very low risk of amputation or re intervention. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis, Pfizer, PharmaMar Novartis, Pfizer, PharmaMar

Soft tissue sarcomas: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Soft tissue sarcomas: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Incidence, Clinical Symptoms and Management of Rectourethral Fistulas After Radical Prostatectomy

Rectourethral fistula is a rare but severe complication after radical prostatectomy and there is no standardized treatment. We retrospectively evaluated the incidence, symptoms and management of rectourethral fistulas based on our experience. From 1999 to 2008 we performed 2,447 radical prostatectomies. Patients in whom postoperative rectourethral fistulas developed were identified. Based on the therapeutic approach patients were categorized into group 1-conservative treatment, group 2-colostomy with or without surgical closure and group 3-immediate surgical closure without colostomy. Rectourethral fistulas developed in 13 of 2,447 patients (0.53%) after radical prostatectomy. The risk of rectourethral fistulas was 3.06-fold higher (p = 0.074) for perineal (7 of 675, 1.04%) than for retropubic prostatectomy (6 of 1,772, 0.34%). In 7 of 13 patients (54%) a rectal lesion was primarily closed at radical prostatectomy. Median followup was 59 months. In all patients in group 1 (3) the fistula closed spontaneously with conservative treatment. None of these patients had fecaluria. In group 2 of the 9 patients 3 (33%) experienced spontaneous fistula closure after temporary colostomy and transurethral catheterization. In this group 6 patients (67%) required additional surgical fistula closure, which was successful in all. Surgical fistula closure (1) without colostomy in presence of fecaluria failed (group 3). The therapeutic concept for rectourethral fistulas should be guided by clinical symptoms. Rectal injury during radical prostatectomy is a major risk factor. In cases with fecaluria colostomy is required for control of infection and may allow spontaneous fistula closure in approximately a third of cases. In the remainder of cases surgical fistula closure was successful in all after protective colostomy.

Chordoma of the Mobile Spine and Sacrum: A Retrospective Analysis of a Series of Patients Surgically Treated at Two Referral Centers

Chordoma is a rare tumor, and its natural history is still not well known. All patients affected by localized chordoma surgically treated at Istituto Ortopedico Rizzoli, Bologna, and Istituto Nazionale Tumori, Milan, Italy, between 1980 and 2008 were reviewed. Local recurrence, distant metastasis, and overall survival (OS) were analyzed both from time of diagnosis and from time of local recurrence/distant metastasis. A multivariable analysis to identify independent prognostic factors was carried out. A total of 138 consecutive patients were identified (sacrum 78%, lumbar spine 15%, cervical-dorsal spine 7%). Of these, 130 underwent surgical resection. Median follow-up was 142 months. The 5- and 10-year OS, local relapse-free survival (LRFS), and distant relapse-free survival (DRFS) were, respectively, 78% and 54%, 52% and 33%, and 86% and 72%. Size was an independent prognostic factor for OS (P value < .001), LRFS (P value: .038), and DRFS (P value: .004), while surgical margins independently predicted LRFS (P value: .003) with a trend for OS. The 5- and 10-year OS, LRFS, and DRFS after the first local relapse were 50% and 26%, 47% and 31%, and 64% and 61%. The size of the recurrence and quality of surgical margins did not influence postrelapse OS. The 5-year OS after the second local relapse was 19%. 22% of patients developed distant metastases with a 5-year post-metastases OS of 33%. Tumor size and surgical margins affected outcome only on initial presentation. However, wide surgery was feasible in a minority of cases. Most patients died of local-regional disease even when metastases occurred. Indeed, long-term prognosis was such that disease-free survival at 10 years was only 26%.

Myoepithelioma within the carpal tunnel: a case report and review of the literature

Myoepitheliomas of the extremity are rare and usually benign, while a minority display malignant features. This case demonstrates the diagnosis and management of myoepithelioma within the carpal tunnel. Clinical and radiological tumour features were evaluated. Hematoxylin and eosin stained tumour sections were examined, and immunohistochemistry was performed. Histology revealed a nodular mass of epithelioid cells in clusters within a myxoid/chondroid stroma. No mitoses were noted. Cytokeratins, neuron-specific enolase, synaptophysin, glial fibrillary acidic protein, and S100 were positive on immunohistochemistry. A literature review revealed very few prior reports of myoepithelioma in the wrist, and limited data concerning any relationship between recurrence and quality of surgical margins. In this case, wide local excision would have significantly compromised dominant hand function, and therefore a marginal excision was deemed appropriate in the context of bland histological features. Surgical margins noted in future case reports will aid clinical decision making.

Increase and Subjective Evaluation of Feedback Stability in Hearing Aids by a Binaural Coherence-Based Noise Reduction Scheme

The effect of a binaural coherence-based noise reduction scheme on the feedback stability margin and sound quality in hearing aids has been analyzed. For comparison, a conventional adaptive feedbac...

Increase and Subjective Evaluation of Feedback Stability in Hearing Aids by a Binaural Coherence-Based Noise Reduction Scheme

The effect of a binaural coherence-based noise reduction scheme on the feedback stability margin and sound quality in hearing aids has been analyzed. For comparison, a conventional adaptive feedback canceler (AFC) and the combination of the adaptive filter with the binaural coherence filter have been tested. The observed quantities are feedback stability and target signal attenuation. An objective measure of feedback stability, i.e., the added stable gain (ASG) was obtained for a number of algorithmic settings and compared to a subjective measure of feedback stability, the added tolerable gain (ATG). In an attempt to eliminate the subjective bias in estimating the ATG, the ldquounbiased added gainrdquo (UAG) is introduced as a new method. Both, objective and subjective measures give similar results for feedback stability. This allows for a valid comparison across different feedback reduction schemes both in isolation and in combination: whereas the ASG of the coherence filter without combination with AFC is negligible, the results indicate that a robust feedback suppression in hearing aids can be achieved if the benefit of de-correlation and the head-shadow effect in binaural hearing aids is used in an advantageous way. The ASG reaches 23 dB for the best combination at the expense of an average target signal attenuation of 15 dB at critical frequencies. The attribute of the coherence filter is that it adaptively limits the maximum gain before feedback becomes audible. The UAG analysis revealed that subjects used a stable quality criterion across the conditions tested and that the group of subjects covered a large range of individual quality criteria.