Search

Postinflammatory, acquired atresia of the external auditory meatus is a relatively rare consequence of chronic otitis media or recurrent external otitis with an annual incidence of 0.6 cases per 100,000 inhabitants. Primary and late results after operative treatment of this condition in 53 ears over 27 years are presented. Perioperative findings are described, and an outline of applied surgical technique is given. Six patients had bilateral involvement. The male-to-female ratio was 1:2, median age at surgery was 46 years, and the median follow-up period was 5 years (range, 4 mo to 13 y). In 11% of the cases, recurrent atresia developed. Early operation is recommended, because cholesteatoma behind the atresia was found in 9%. Hearing improvement has been considerable after removal of the atresia with primary closure of airbone gap within 20 dB in 90% of the cases. [ABSTRACT FROM AUTHOR]

Background: High frequency chest wall oscillation (HFCWO) is a form of airway clearance therapy that has been available since the mid-1990s and is routinely used by patients suffering from retained pulmonary secretions. Patients with cystic fibrosis (CF), neuromuscular disease (NMD), and other disorders, including bronchiectasis (BE) and COPD (without BE), are commonly prescribed this therapy. Limited evidence exists describing HFCWO use in the BE population, its impact on long-term management of disease, and the specific patient populations most likely to benefit from this therapy. This study sought to characterize the clinical characteristics of patients with BE who have documented use of HFCWO at baseline and 1-year follow-up., Methods: An analysis from a large national database registry of patients with BE was performed. Demographic and clinical characteristics of all patients receiving HFCWO therapy at baseline are reported. Patients were stratified into two groups based on continued or discontinued use of HFCWO therapy at 1-year follow-up., Results: Over half (54.8 %) of patients who reported using HFCWO therapy had a Modified Bronchiectasis Severity Index (m-BSI) classified as severe, and the majority (81.4 %) experienced an exacerbation in the prior two years. Of patients with 1-year follow-up data, 73 % reported continued use of HFCWO. Compared to patients who discontinued therapy, these patients were more severe at baseline and at follow-up suggesting that patients with more severe disease are more likely to continue HFCWO therapy., Conclusions: Patients who have more severe disease and continue to experience exacerbations and hospitalizations are more likely to continue HFCWO therapy., Clinical Trial Registration: NA., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ashwin Basavaraj reports writing assistance was provided by LeeAnn Phipps. AB - Consultant and Advisory Board for Baxter, Insmed, Physio-Assist, Dymedso, Zambon. Medical education consulting for Tactile Medical. Principal investigator on clinical trial sponsored by Baxter with funding to institution. Educational grant funding received from Insmed to institution. RC - No disclosures to report. BB – Employee relationship with Baxter. MM - Grant funding from Insmed and COPD foundation. Consulting fees from Insmed, Boehringer-Ingelheim, and Tactile Medical. Payment/honoraria for presentations/lectures from Insmed. Participation on data safety monitoring/advisory board for AN2, Renovion. TA - Support as medical director of the Bronchiectasis and NTM research registry. Has participated in clinical trials sponsored by Bayer, Aradigm, Zambon., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: The extracellular matrix (ECM) plays an integral role in wound healing. It provides both structure and growth factors that allow for the organised cell proliferation. Large or complex tissue defects may compromise host ECM, creating an environment that is unfavourable for the recovery of anatomical function and appearance. Acellular dermal matrices (ADMs) have been developed from a variety of sources, including human (HADM), porcine (PADM) and bovine (BADM), with multiple different processing protocols. The objective of this report is to provide an overview of current literature assessing the clinical utility of ADMs across a broad spectrum of applications., Methods: PubMed, MEDLINE, EMBASE, Scopus, Cochrane and Web of Science were searched using keywords 'acellular dermal matrix', 'acellular dermal matrices' and brand names for commercially available ADMs. Our search was limited to English language articles published from 1999 to 2020 and focused on clinical data., Results: A total of 2443 records underwent screening. After removing non-clinical studies and correspondence, 222 were assessed for eligibility. Of these, 170 were included in our synthesis of the literature. While the earliest ADMs were used in severe burn injuries, usage has expanded to a number of surgical subspecialties and procedures, including orthopaedic surgery (e.g. tendon and ligament reconstructions), otolaryngology, oral surgery (e.g. treating gingival recession), abdominal wall surgery (e.g. hernia repair), plastic surgery (e.g. breast reconstruction and penile augmentation), and chronic wounds (e.g. diabetic ulcers)., Conclusion: Our understanding of ADM's clinical utility continues to evolve. More research is needed to determine which ADM has the best outcomes for each clinical scenario., Lay Summary: Large or complex wounds present unique reconstructive and healing challenges. In normal healing, the extracellular matrix (ECM) provides both structural and growth factors that allow tissue to regenerate in an organised fashion to close the wound. In difficult or large soft-tissue defects, however, the ECM is often compromised. Acellular dermal matrix (ADM) products have been developed to mimic the benefits of host ECM, allowing for improved outcomes in a variety of clinical scenarios. This review summarises the current clinical evidence regarding commercially available ADMs in a wide variety of clinical contexts., Competing Interests: Declaration of conflicting interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: SBH1038313. Though they are not directly related to this case report, the authors would like to disclose the following support for Brendan MacKay: Paid teaching for TriMed. Paid teaching and consulting, as well as research support from AxoGen. Paid consulting for Baxter/Synovis and GLG. The remaining authors have nothing to disclose., (© The Author(s) 2022.)

Proline dehydrogenase (PRODH) is a p53-inducible inner mitochondrial membrane flavoprotein linked to electron transport for anaplerotic glutamate and ATP production, most critical for cancer cell survival under microenvironmental stress conditions. Proposing that PRODH is a unique mitochondrial cancer target, we structurally model and compare its cancer cell activity and consequences upon exposure to either a reversible ( S -5-oxo: S -5-oxo-2-tetrahydrofurancarboxylic acid) or irreversible ( N -PPG: N -propargylglycine) PRODH inhibitor. Unlike 5-oxo, the suicide inhibitor N -PPG induces early and selective decay of PRODH protein without triggering mitochondrial destruction, consistent with N -PPG activation of the mitochondrial unfolded protein response. Fly and breast tumor (MCF7)-xenografted mouse studies indicate that N -PPG doses sufficient to phenocopy PRODH knockout and induce its decay can be safely and effectively administered in vivo Among breast cancer cell lines and tumor samples, PRODH mRNA expression is subtype dependent and inversely correlated with glutaminase (GLS1) expression; combining inhibitors of PRODH ( S -5-oxo and N -PPG) and GLS1 (CB-839) produces additive if not synergistic loss of cancer cell (ZR-75-1, MCF7, DU4475, and BT474) growth and viability. Although PRODH knockdown alone can induce cancer cell apoptosis, the anticancer potential of either reversible or irreversible PRODH inhibitors is strongly enhanced when p53 is simultaneously upregulated by an MDM2 antagonist (MI-63 and nutlin-3). However, maximum anticancer synergy is observed in vitro when the PRODH suicide inhibitor, N -PPG, is combined with both GLS1-inhibiting and a p53-upregulating MDM2 antagonist. These findings provide preclinical rationale for the development of N -PPG-like PRODH inhibitors as cancer therapeutics to exploit synthetic lethal interactions with p53 upregulation and GLS1 inhibition., (©2019 American Association for Cancer Research.)

Background: Fast and accurate mapping and localization of the retinal vasculature is critical to increasing the effectiveness and clinical utility of robot-assisted intraocular microsurgery such as laser photocoagulation and retinal vessel cannulation., Methods: The proposed EyeSLAM algorithm delivers 30 Hz real-time simultaneous localization and mapping of the human retina and vasculature during intraocular surgery, combining fast vessel detection with 2D scan-matching techniques to build and localize a probabilistic map of the vasculature., Results: In the harsh imaging environment of retinal surgery with high magnification, quick shaky motions, textureless retina background, variable lighting and tool occlusion, EyeSLAM can map 75% of the vessels within two seconds of initialization and localize the retina in real time with a root mean squared (RMS) error of under 5.0 pixels (translation) and 1° (rotation)., Conclusions: EyeSLAM robustly provides retinal maps and registration that enable intelligent surgical micromanipulators to aid surgeons in simulated retinal vessel tracing and photocoagulation tasks., (Copyright © 2017 John Wiley & Sons, Ltd.)

Performing micromanipulation and delicate operations in submillimeter workspaces is difficult because of destabilizing tremor and imprecise targeting. Accurate micromanipulation is especially important for microsurgical procedures, such as vitreoretinal surgery, to maximize successful outcomes and minimize collateral damage. Robotic aid combined with filtering techniques that suppress tremor frequency bands increases performance; however, if knowledge of the operator's goals is available, virtual fixtures have been shown to further improve performance. In this paper, we derive a virtual fixture framework for active handheld micromanipulators that is based on high-bandwidth position measurements rather than forces applied to a robot handle. For applicability in surgical environments, the fixtures are generated in real-time from microscope video during the procedure. Additionally, we develop motion scaling behavior around virtual fixtures as a simple and direct extension to the proposed framework. We demonstrate that virtual fixtures significantly outperform tremor cancellation algorithms on a set of synthetic tracing tasks (p < 0.05). In more medically relevant experiments of vein tracing and membrane peeling in eye phantoms, virtual fixtures can significantly reduce both positioning error and forces applied to tissue (p < 0.05).

Computer-aided intraocular surgery requires precise, real-time knowledge of the vasculature during retinal procedures such as laser photocoagulation or vessel cannulation. Because vitreoretinal surgeons manipulate retinal structures on the back of the eye through ports in the sclera, voluntary and involuntary tool motion rotates the eye in the socket and causes movement to the microscope view of the retina. The dynamic nature of the surgical workspace during intraocular surgery makes mapping, tracking, and localizing vasculature in real time a challenge. We present an approach that both maps and localizes retinal vessels by temporally fusing and registering individual-frame vessel detections. On video of porcine and human retina, we demonstrate real-time performance, rapid convergence, and robustness to variable illumination and tool occlusion.

Peeling delicate retinal membranes, which are often less than 5 µm thick, is one of the most challenging retinal surgeries. Preventing rips and tears caused by tremor and excessive force can decrease injury and reduce the need for follow up surgeries. We propose the use of a fully handheld microsurgical robot to suppress tremor while enforcing helpful constraints on the motion of the tool. Using stereo vision and tracking algorithms, the robot activates motion-scaled behavior as the tip reaches the surface, providing finer control during the critical step of engaging the membrane edge. A hard virtual fixture just below the surface limits the total downward force that can be applied. Furthermore, velocity limiting during the peeling helps the surgeon maintain a smooth, constant force while lifting and delaminating the membrane. On a phantom consisting of plastic wrap stretched across a rubber slide, we demonstrate our approach reduces maximum force by 40-70%.

Injecting clot-busting drugs such as t-PA into tiny vessels thinner than a human hair in the eye is a challenging procedure, especially since the vessels lie directly on top of the delicate and easily damaged retina. Various robotic aids have been proposed with the goal of increasing safety by removing tremor and increasing precision with motion scaling. We have developed a fully handheld micromanipulator, Micron, that has demonstrated reduced tremor when cannulating porcine retinal veins in an "open sky" scenario. In this paper, we present work towards handheld robotic cannulation with the goal of vision-based virtual fixtures guiding the tip of the cannula to the vessel. Using a realistic eyeball phantom, we address sclerotomy constraints, eye movement, and non-planar retina. Preliminary results indicate a handheld micromanipulator aided by visual control is a promising solution to retinal vessel occlusion.

We describe the design and performance of a hand-held actively stabilized tool to increase accuracy in micro-surgery or other precision manipulation. It removes involuntary motion such as tremor by actuating the tip to counteract the effect of the undesired handle motion. The key components are a three-degree-of-freedom piezoelectric manipulator that has 400 μm range of motion, 1 N force capability, and bandwidth over 100 Hz, and an optical position measurement subsystem that acquires the tool pose with 4 μm resolution at 2000 samples/s. A control system using these components attenuates hand motion by at least 15 dB (a fivefold reduction). By considering the effect of the frequency response of Micron on the human visual feedback loop, we have developed a filter that reduces unintentional motion, yet preserves intuitive eye-hand coordination. We evaluated the effectiveness of Micron by measuring the accuracy of the human/machine system in three simple manipulation tasks. Handheld testing by three eye surgeons and three non-surgeons showed a reduction in position error of between 32% and 52%, depending on the error metric.

This paper describes an inexpensive pico-projector-based augmented reality (AR) display for a surgical microscope. The system is designed for use with Micron, an active handheld surgical tool that cancels hand tremor of surgeons to improve microsurgical accuracy. Using the AR display, virtual cues can be injected into the microscope view to track the movement of the tip of Micron, show the desired position, and indicate the position error. Cues can be used to maintain high performance by helping the surgeon to avoid drifting out of the workspace of the instrument. Also, boundary information such as the view range of the cameras that record surgical procedures can be displayed to tell surgeons the operation area. Furthermore, numerical, textual, or graphical information can be displayed, showing such things as tool tip depth in the work space and on/off status of the canceling function of Micron.

Stapes footplate surgery is complex and delicate. This surgery is carried out in the middle ear to improve hearing. High accuracy is required to avoid critical tissues and structures near the surgical worksite. By suppressing the surgeon's tremor during the operation, accuracy can be improved. In this paper, a fully handheld active micromanipulator known as Micron is evaluated for its feasibility for this delicate operation. An ergonomic handle, a custom tip, and a brace attachment were designed for stapes footplate surgery and tested in a fenestration task through a fixed speculum. Accuracy was measured during simulated surgery in two different scenarios: Micron off (unaided) and Micron on (aided), both with image guidance. Preliminary results show that Micron significantly reduces the mean position error and the mean duration of time spent in specified dangerous zones.

Medical augmented reality has undergone much development recently. However, there is a lack of studies quantitatively comparing the different display options available. This paper compares the effects of different graphical overlay systems in a simple micromanipulation task with "soft" visual servoing. We compared positioning accuracy in a real-time visually-guided task using Micron, an active handheld tremor-canceling microsurgical instrument, using three different displays: 2D screen, 3D screen, and microscope with monocular image injection. Tested with novices and an experienced vitreoretinal surgeon, display of virtual cues in the microscope via an augmented reality injection system significantly decreased 3D error (p &#60; 0.05) compared to the 2D and 3D monitors when confounding factors such as magnification level were normalized.

Active compensation of physiological tremor for handheld micromanipulators depends on fast control and actuation responses. Because of real-world latencies, real-time compensation is usually not completely effective at eliminating unwanted hand motion. By modeling tremor, more effective cancellation is possible by anticipating future hand motion. We propose a feedforward control strategy that utilizes tremor velocity from a state-estimating Kalman filter. We demonstrate that estimating hand motion in a feedforward controller overcomes real-world latencies in micromanipulator actuation. In hold-still tasks with a fully handheld micromanipulator, the proposed feedforward approach improves tremor rejection by over 50%.

Precise movement during micromanipulation becomes difficult in submillimeter workspaces, largely due to the destabilizing influence of tremor. Robotic aid combined with filtering techniques that suppress tremor frequency bands increases performance; however, if knowledge of the operator's goals is available, virtual fixtures have been shown to greatly improve micromanipulator precision. In this paper, we derive a control law for position-based virtual fixtures within the framework of an active handheld micromanipulator, where the fixtures are generated in real-time from microscope video. Additionally, we develop motion scaling behavior centered on virtual fixtures as a simple and direct extension to our formulation. We demonstrate that hard and soft (motion-scaled) virtual fixtures outperform state-of-the-art tremor cancellation performance on a set of artificial but medically relevant tasks: holding, move-and-hold, curve tracing, and volume restriction.

Airway secretions and infections are common in cerebral palsy and neuromuscular diseases. Chest physiotherapy is standard therapy but effort is substantial. High-frequency chest wall oscillation is used in cystic fibrosis but tolerability and safety data in cerebral palsy and neuromuscular disease are limited. A prospective, randomized, controlled trial of high-frequency chest wall oscillation and standard chest physiotherapy was performed in participants with neuromuscular disease or cerebral palsy. Outcome measures included respiratory-related hospitalizations, antibiotic therapy, chest radiographs, and polysomnography. Care-givers were questioned regarding therapy adherence. A total of 28 participants enrolled, 23 completed (12 chest physiotherapy, mean study period 5 months). No adverse outcomes were reported. Adherence to prescribed regimen was higher with high-frequency chest wall oscillation (P = .036). Our data suggest safety, tolerability, and better compliance with high-frequency chest wall oscillation. Improvement in airway clearance may help prevent hospitalizations. Larger controlled trials are required to confirm these results.

Background and Objective: In laser retinal photocoagulation, hundreds of dot-like burns are applied. We introduce a robot-assisted technique to enhance the accuracy and reduce the tedium of the procedure., Materials and Methods: Laser burn locations are overlaid on preoperative retinal images using common patterns such as grids. A stereo camera/monitor setup registers and displays the planned burn locations overlaid on real-time video. Using an active handheld micromanipulator, a 7 x 7 grid of burns spaced 650 microm apart is applied to both paper slides and porcine retina in vitro using 30 milliseconds laser pulses at 532 nm. Two scenarios were tested: unaided, in which the micromanipulator is inert and the laser fires at a fixed frequency, and aided, in which the micromanipulator actively targets burn locations and the laser fires automatically upon target acquisition. Error is defined as the distance from the center of the observed burn mark to the preoperatively selected target location., Results: An experienced retinal surgeon performed trials with and without robotic assistance, on both paper slides and porcine retina in vitro. In the paper slide experiments at an unaided laser repeat rate of 0.5 Hz, error was 125+/-62 microm with robotic assistance and 149+/-76 microm without (P < 0.005), and trial duration was 70+/-8 seconds with robotic assistance and 97+/-7 seconds without (P < 0.005). At a repeat rate of 1.0 Hz, error was 129+/-69 microm with robotic assistance and 166+/-91 microm without (P < 0.005), and trial duration was 26+/-4 seconds with robotic assistance and 47+/-1 seconds without (P < 0.005). At a repeat rate of 2.0 Hz on porcine retinal tissue, error was 123+/-69 microm with robotic assistance and 203+/-104 microm without (P < 0.005)., Conclusion: Robotic assistance can increase the accuracy of laser photocoagulation while reducing the duration of the operation.

HeartLander is a small, mobile robot designed to assist surgical procedures on the surface of the heart. It crawls within the pericardial sac surrounding the heart. Numerous potential clinical uses for HeartLander involve injections or other interventions at multiple locations on the epicardial surface. To minimize treatment time, we have developed an algorithm that optimizes a plan for reaching a given set of treatment targets. Results from in vitro evaluation on a beating heart model show improvement over a greedy technique.

Cannulation of small retinal vessels is often prohibitively difficult for surgeons, since physiological tremor often exceeds the narrow diameter of the vessel (40-120 microm). Using an active handheld micromanipulator, we introduce an image-guided robotic system that reduces tremor and provides smooth, scaled motion during the procedure. The micromanipulator assists the surgeon during the approach, puncture, and injection stages of the procedure by tracking the pipette and anatomy viewed under the microscope. In experiments performed ex vivo by an experienced retinal surgeon on 40-60 microm vessels in porcine eyes, the success rate was 29% (2/7) without the aid of the system and 63% (5/8) with the aid of the system.

In microsurgery, a surgeon often deals with anatomical structures of sizes that are close to the limit of the human hand accuracy. Robotic assistants can help to push beyond the current state of practice by integrating imaging and robot-assisted tools. This paper demonstrates control of a handheld tremor reduction micromanipulator with visual servo techniques, aiding the operator by providing three behaviors: snap-to, motion-scaling, and standoff-regulation. A stereo camera setup viewing the workspace under high magnification tracks the tip of the micromanipulator and the desired target object being manipulated. Individual behaviors activate in task-specific situations when the micromanipulator tip is in the vicinity of the target. We show that the snap-to behavior can reach and maintain a position at a target with an accuracy of 17.5 ± 0.4μm Root Mean Squared Error (RMSE) distance between the tip and target. Scaling the operator's motions and preventing unwanted contact with non-target objects also provides a larger margin of safety.

Introduction: Coblation (Co) is a relatively new technique, which may offer a better postoperative course after tonsillectomy than traditional techniques. The purpose of this study was to determine whether Co outperforms classic dissection. Coblation uses radiofrequency energy to excite the electrolytes in a saline solution, creating a precisely focused plasma. The plasma's energized particles have sufficient energy to break molecular bonds within tissue, causing the tissue to dissolve at temperatures between 40 degrees C and 70 degrees C., Material and Methods: A case-control study was conducted in which 26 patients undergoing Co tonsillectomy were matched concerning gender, age and the surgeon's charge with 26 patients undergoing classic tonsillectomy. Furthermore, to compare the rates of postoperative haemorrhage, we reviewed the health records of all patients undergoing Co (60 patients) and routine dissection tonsillectomy (403) at Roskilde County Hospital., Results: Intraoperative bleeding was significantly lower in the Co group (median (MD) 5.0 ml; range (R) 1-32 ml) than in the control group (MD 10.0 ml; R 5-200 ml) (p < 0.0001). The median operation time was also significantly shorter for the Co group (23 min.; R 13-40 min. vs. 32 min.; R 21-63 min.; p = 0.002). Postoperatively, there was no significant difference between the two groups regarding pain scores, analgesics intake, time to return to work and normal diet or weight changes. Neither the primary (0% vs. 2%, p = 0.60) nor the secondary (3.3% vs. 2.5%, p = 0,66) haemorrhage rate was significantly different between Co and traditional tonsillectomy., Conclusion: The intraoperative bleeding was lower and the surgery times were shorter in the Co group compared with classic dissection. There was no difference in the postoperative haemorrhage rate between the two tonsillectomy methods.

Laser photocoagulation is a standard interventional tool in vitreoretinal surgery. Commonly applied treatments such as grid photocoagulation and panretinal photocoagulation involve the application of hundreds of dot-like laser burns to the retina. In order to enhance the accuracy and reduce the tedium of this procedure, we are developing a robot-assisted technique for retinal laser photocoagulation that includes software for planning patterns of laser burns on a retinal image and uses an active handheld micromanipulator known as Micron in order to apply the pattern of burns to the retina. The paper describes the system and presents preliminary results. In a sample 7x7 pattern of lesions applied to an artificial surface, the system demonstrated a mean position error of 43+/-23 microm.

Multiple tumours of different histological type of the salivary glands are extremely rare. Here we report a 72-year-old woman who was diagnosed with simultaneously occurring Warthin's tumour of the left parotid and mixed tumour of the homolateral submandibular gland. To our knowledge this combination of histology and localization has not been reported previously. This case also illustrates the importance of thorough examination even after the identification of a single tumour, as multiple synchronous primary tumours--even if rare--can be a diagnostic possibility.

Tremor was recorded under simulated vitreoretinal microsurgical conditions as subjects attempted to hold an instrument motionless. Several autoregressive models (AR, ARMA, multivariate, and nonlinear) are generated to predict the next value of tremor. It is shown that a sixth order ARMA model predictor can predict a tremor having an amplitude of 96.6 +/- 84.5 microns RMS with an error of 8.2 +/- 5.9 microns RMS, a mean improvement of 47.5% over simple last-value prediction.

A case of long term retention of a bronchial foreign body in a 62-year old female patient is presented, which mimicked lung carcinoma. Despite a negative history of choking, the diagnosis airway foreign body should be kept in mind.

The hospital records of 99 children with foreign bodies in the airways (n = 51) or oesophagus (n = 48) were reviewed with respect to occurrence, course of disease and mortality. Childhood death records in Denmark over a ten year period due to asphyxiation by food were surveyed. A third of the patients with oesophageal foreign bodies had respiratory symptoms. Most children with airway foreign bodies were aged 1 to 3 years and generally had a positive history of choking. The dominating symptoms were cough, wheezing and cyanosis. Chest X-ray was normal in 25%. There were no complications during bronchoscopy. The most common foreign bodies extracted were nuts (29%). The estimated death rate due to airway foreign bodies is 0.9 per 100,000 children in Denmark per year. Rigid oesophagoscopy and bronchoscopy should be performed promptly on suspicion of foreign bodies located in the oesophagus or airways to ensure fast recovery. Nuts, tablets and other small items should not be within reach of small children.

Unlabelled: At Glostrup Hospital, Copenhagen, exceptionally few stapedectomies were performed during the period 1979-1985. The audiological results five to eleven years after the operation were investigated in 64 patients. About half of the patients were operated using large fenester technique, the other half using small fenester technique. All patients but two were operated by the same expert surgeon. The initial results showed good stability with an unchanged median hearing gain of 30 dB. Eighty-five percent of the patients had an SRT < or = 35 dB HL in contrast to 89% at the 1-year follow-up (and five percent preoperatively). Eighty-two percent had an air-bone gap < or = 20 dB in contrast to 93% at 1-year follow-up (and 10% preoperatively). None of the patients had spontaneously developed severe sensorineural hearing loss, which was, however present in two patients as a direct result of the operation. In one of the patients it was caused by granuloma formation around the prosthesis, in the other patient it developed after a revision procedure. Both patients were operated using large fenester technique, which in general gave less satisfactory primary hearing improvement and less stable thresholds than small fenester technique., In Conclusion: Even under conditions with few operations per year the overall long term results of stapedectomy are satisfactory when performed by few trained ear surgeons, and in particular if small fenester technique is used. The risk of sensorineural hearing loss is primarily related to the operation.

The human amnion cell line FL was found to be more tumorigenic than HeLa cells when used as a positive control in heterotransplantation assays. FL cells formed significantly larger locally invasive tumors than HeLa cells in both Balb/c/nu/nu mice and ATG-treated newborn Wistar rats. In addition, FL cells resulted in metastatic growths in the lungs of two of 12 mice six weeks and in 10 of 36 rats three weeks after inoculation. HeLa cells did not produce metastases in either mice or rats. Both these cell lines were obtained from the American Type Culture Collection. Heterotransplantation experiments with a variety of animal host systems confirmed previous findings that newborn Wistar rats treated with rat ATG were the most sensitive to tumor growth. Vero and LLC-MK2 continuous monkey kidney cells formed small, non-progressively growing tumors showing tubule formation and occasional mitoses. LLC-MK2 cells were found to be more pleomorphic in appearance and with more mitoses than Vero cells but neither cell line showed any evidence of distant metastatic growth in any of several organs examined. The human lymphoblastoid cell line Namalwa produced large invasive tumors at the inoculation site but no distant metastases. In the chick embryo skin test it was found that MI values (mitotic index--percentage of cells in mitosis) gave more reproducible results and were less time-consuming than counting mean mitoses per section. Significant differences were found between Vero, LLC-MK2, HeLa and FL cells with Vero giving the lowest and FL the highest values. The use of MI values enhanced the sensitivity of the chick embryo skin test which was found to be a rapid and valuable screening test for tumorigenicity.

The changes in reimbursement to hospitals by third party payers make it essential for hospital administrators to forecast their hospitals' reimbursement potential. Although models have been developed to predict and maximize census, forecast future demand for hospital care, and forecast the revenue budget, none of the models addresses how the physician directly affects the hospital reimbursement potential through office practice admissions. This study analyzes the admitting physician's patients by third party payer and presents a method to assist in using a physician's past hospital admissions to forecast a hospital's admissions and reimbursement potential.

Studies on the tumorigenicity of Vero kidney cells of Cercopithecus aethiops monkey origin were extended to various passage levels of BSC-1 aneuploid cells and to low passage CV-1 diploid cells (derived also from C. aethiops monkey kidney). It was found that BSC-1 cells -- like Vero cells -- showed increased tumorigenicity with increasing passage level in antithymocyte globulin (ATG) treated newborn rats and in nude mice. Cells passaged over 250 times in cultures formed invasive adenocarcinomas in newborn rats. Their malignant tumor growth was further demonstrated around the 500 passage level when tumor metastases were detected in the lungs of four of the 14 inoculated rats. Vero cells induced such lung metastases in rats already at passage 227. CV-1 diploid cells at low passage level produced small nodules of epithelioid cells in newborn rats at 6th day after inoculation that had disappeared by the 21st day, and caused no local invasion nor lung metastasis. In vitro tumorigenicity tests on BSC-1 and CV-1 cells, using chick embryo skin, human muscle and colony formation in agarose, confirmed the animal test results. The results of this study indicate that BSC-1 and Vero cell lines at low and high passage levels may prove to be useful tools to study the molecular basis of malignancy.