Management of Maxillofacial Trauma in Pregnant Women

INTRODUCTION

Trauma during pregnancy deserves special attention as management must be directed towards both the mother and the fetus. Management of maxillofacial fractures in pregnancy can adversely affect the well-being of the fetus by impinging on normal functions such as respiration, mastication, and nutrition. Pregnancy complicates the management of facial injury due to the maintenance of the patent airway, anesthesia considerations, and imaging restraints. The purpose of this study is to use three illustrative from our own institution to further elucidate education on the management of mandible fracture in pregnancy with a focus on multidisciplinary treatment and outcomes.

METHODS

A retrospective chart review was performed for all cases of facial fractures admitted to Ryder Trauma Center from 2012 to 2022. During this time, 4,910 patients presented with facial fractures 1319 patients were female. Three of the patients were pregnant at the time of admission. Demographics, mechanism of injury, associated injuries, and management information were collected.

RESULTS

Patient 1 was a 20-year-old female presented to Ryder Trauma Center following a motor vehicle collision. She was 17 weeks pregnant at the time of admission and was found to have a left mandibular angle fracture. Patient 2 was a 14-year-old female who presented to Ryder Trauma Center status post gunshot wound to the mandible after she and her brother were unknowingly playing with a loaded gun. She was 18 weeks pregnant at the time of admission, with a past medical history of domestic violence, suicidal ideation, and major depressive disorder. Patient 3 was a 20-year-old female 36 weeks pregnant at the time of admission. She presented with a right paraymphyseal fracture and left mandibular angle fracture as a result of falling on the stairs. Patients all underwent surgical repair of fractures.

On radar and radio exposure and cancer in the military setting

INTRODUCTION

In 2018, we reported a case series of 47 patients diagnosed with cancer following several years of exposure to high-intensity whole-body radiofrequency radiation (RFR) using the parameter of percentage frequency (PF). Consistent high and statistically significant PFs of hematolymphoid (HL) cancers were found in this group and in four previous reports on RFR-exposed groups in Belgium, Poland and Israel together with increased all-cancers rates. In this paper we report a new series of 46 young cancer patients who were exposed during military service to such radiation.

MATERIALS AND METHODS

The new group of patients comprises Israeli soldiers previously exposed to occupational RFR. The patients were self-selected to enroll in the research in cooperation with an NGO assisting patients with administrative counseling and legal and social services. The new group of patients was studied with respect to distribution (proportion) of cancer types using the method of PF. When possible, cancer risk ratios (RR) were estimated too. The results are compared to those of other occupational groups in three countries.

RESULTS

Median age at diagnosis was 23 years; duration of exposure was between 1 and 3 years and the latencies were short, median 4.6 years. The PF of HL cancers was 41.3%, 95% CI (27%-57%), versus 22.7% expected in non-exposed subjects matched for age and gender profiles, p = 0.003; 19 out of the 46 patients had HL cancers. The PF of Hodgkin lymphoma cancers was 21.7%, 95%CI (11%-36%), versus 11.6% expected, p = 0.033. For a subgroup of 6 patients, the number of soldiers in the units was known, and we were able estimate approximately the overall cancer risk ratio (RR) after 8 years as being 8.0 with 95% CI (2.9, 17), p < 0.002, with only 0.75 cases expected from the Cancer Registry data. In this subgroup, there were 3 HL cancer cases and 3 non-HL cases. Sarcoma PF was higher than expected, 7 out of the 46 patients were diagnosed with sarcoma, PF = 15.2%, 95%CI (6.3%-28.9%), p = 0.04 versus the expected PF of 7%.

CONCLUSION

The HL PF was high and consistent with previous reports. Epidemiological studies on excess risk for HL and other cancers, brain tumors in cellphone users, and experimental studies on RFR and carcinogenicity strongly point to a cause-effect relationship. It is mandatory to reduce the RFR exposure of all personnel to that of the typical community levels, including the peak level of radar pulses. Radiation protection, safety instructions, cancer risk warnings and quantitative data on individual exposure together with regular medical monitoring must be instituted for all personnel exposed to such risks. The findings from our study add to the growing body of evidence underscoring the gross inadequacy of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) thermal standards. Based on our findings and on the previous accumulated research, we endorse the recommendations to reclassify RFR exposure as a human carcinogen, International Agency for Research on Cancer (IARC) group 1.

A review of AI and Data Science support for cancer management

INTRODUCTION

Thanks to improvement of care, cancer has become a chronic condition. But due to the toxicity of treatment, the importance of supporting the quality of life (QoL) of cancer patients increases. Monitoring and managing QoL relies on data collected by the patient in his/her home environment, its integration, and its analysis, which supports personalization of cancer management recommendations. We review the state-of-the-art of computerized systems that employ AI and Data Science methods to monitor the health status and provide support to cancer patients managed at home.

OBJECTIVE

Our main objective is to analyze the literature to identify open research challenges that a novel decision support system for cancer patients and clinicians will need to address, point to potential solutions, and provide a list of established best-practices to adopt.

METHODS

We designed a review study, in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, analyzing studies retrieved from PubMed related to monitoring cancer patients in their home environments via sensors and self-reporting: what data is collected, what are the techniques used to collect data, semantically integrate it, infer the patient's state from it and deliver coaching/behavior change interventions.

RESULTS

Starting from an initial corpus of 819 unique articles, a total of 180 papers were considered in the full-text analysis and 109 were finally included in the review. Our findings are organized and presented in four main sub-topics consisting of data collection, data integration, predictive modeling and patient coaching.

CONCLUSION

Development of modern decision support systems for cancer needs to utilize best practices like the use of validated electronic questionnaires for quality-of-life assessment, adoption of appropriate information modeling standards supplemented by terminologies/ontologies, adherence to FAIR data principles, external validation, stratification of patients in subgroups for better predictive modeling, and adoption of formal behavior change theories. Open research challenges include supporting emotional and social dimensions of well-being, including PROs in predictive modeling, and providing better customization of behavioral interventions for the specific population of cancer patients.

Radio frequency radiation-related cancer: assessing causation in the occupational/military setting

BACKGROUND AND AIM

We reexamine whether radio frequency radiation (RFR) in the occupational and military settings is a human carcinogen.

METHODS

We extended an analysis of an already-reported case series of patients with cancer previously exposed to whole-body prolonged RFR, mainly from communication equipment and radar. We focused on hematolymphatic (HL) cancers. We used analysis by percentage frequency (PF) of a cancer type, which is the proportion of a specific cancer type relative to the total number of cancer cases. We also examined and analyzed the published data on three other cohort studies from similar military settings from different countries.

RESULTS

The PF of HL cancers in the case series was very high, at 40% with only 23% expected for the series age and gender profile, confidence interval CI95%: 26-56%, p<0.01, 19 out of 47 patients had HL cancers. We also found high PF for multiple primaries. As for the three other cohort studies: In the Polish military sector, the PF of HL cancers was 36% in the exposed population as compared to 12% in the unexposed population, p<0.001. In a small group of employees exposed to RFR in Israeli defense industry, the PF of HL cancers was 60% versus 17% expected for the group age and gender profile, p<0.05. In Belgian radar battalions the HL PF was 8.3% versus 1.4% in the control battalions as shown in a causes of deaths study and HL cancer mortality rate ratio was 7.2 and statistically significant. Similar findings were reported on radio amateurs and Korean war technicians. Elevated risk ratios were previously reported in most of the above studies.

CONCLUSIONS

The consistent association of RFR and highly elevated HL cancer risk in the four groups spread over three countries, operating different RFR equipment types and analyzed by different research protocols, suggests a cause-effect relationship between RFR and HL cancers in military/occupational settings. While complete measurements of RFR exposures were not available and rough exposure assessments from patients interviews and from partial exposure data were used instead, we have demonstrated increased HL cancers in occupational groups with relatively high RFR exposures. Our findings, combined with other studies, indicate that exposures incurred in the military settings evaluated here significantly increased the risk of HL cancers. Accordingly, the RFR military exposures in these occupations should be substantially reduced and further efforts should be undertaken to monitor and measure those exposures and to follow cohorts exposed to RFR for cancers and other health effects. Overall, the epidemiological studies on excess risk for HL and other cancers together with brain tumors in cellphone users and experimental studies on RFR and carcinogenicity make a coherent case for a cause-effect relationship and classifying RFR exposure as a human carcinogen (IARC group 1).

Analysis of the Process of Encoding Guidelines: A Comparison of GLIF2 and GLIF3

Objectives: This study aims to evaluate the use of a modified version of the Guideline Interchange Format (GLIF), GLIF3, in the translation of clinical practice guidelines into an electronically encoded form such that they may be shared among various clinical institutions and settings.

Methods: Based on theories and methods from cognitive science, the encoding of two clinical practice guidelines into two guideline modeling methods (GLIF3 and an earlier version, GLIF2) by two medical informaticians was captured on video and transcribed and annotated for analysis.

Results: Differing in both content and structure, the representations developed in GLIF3 were found to contain a greater level of representational detail and less ambiguity than those developed in GLIF2.

Conclusions: The use of GLIF3 in the encoding of clinical guidelines offers significant improvements due to its greater formality as compared to earlier versions of GLIF.

Discussion of “Attitude of Physi -cians Towards Automatic Alerting in Computerized Physician Order Entry Systems”

With these comments on the paper “Attitude of Physicians Towards Automatic Alerting in Computerized Physician Order Entry Systems”, written by Martin Jung and co authors, with Dr. Elske Ammenwerth as senior author [1], the journal wants to stimulate a broad discussion on computerized physi cian order entry systems. An international group of experts have been invited by the editor of Methods to comment on this paper. Each of the invited commentaries forms one section of this paper.

Imperfect squeezing flow viscosimetry for commercial refried beans / Viscosimetría de extensión biaxial imperfecta de frijoles refritos

The imperfect squeezing flow patterns of almost intact canned fat free and vegetarian refried beans of two national brands were determined using all Teflon and grooved metal sensors. The force versus height curves were remarkably reproducible and characteristic of the products and brands irrespec tive of the upper plate's diameter and the sensor's finish. Both types of product had a very high degree of plasticity but those of one brand were more sensitive to the deformation rate. The consis tency of the corresponding products of the two brands could be compared in terms of an apparent stress at a predetermined height (1.5 and 2.5 mm), and their yield stress in terms of an apparent residual stress, or percent force drop, after a given time (60 and 120 s). At a deformation rate of 6 mm/min the apparent stress at a height of 1.5 mm was in the order of 9-11 or 15-19 kPa for the fat free products and 14-15 versus 18-20 kPa for the vegetarian products. After 120 s of relaxation, the stress decayed to about 30 to 60% of its initial level depending on the product and brand. The re sidual stress level was generally higher when determined with the grooved metal sensors. The prod ucts with relatively higher stresses at a given height also showed a relatively slower relaxation pat tern suggesting that consistency and apparent yield stress may be related rather than independent properties of refried beans.

Review: Mechanical properties of dry cellular solid foods / Revisión: Propiedades mecánicas de alimentos celulares sólidos

The compressive stress-strain relationships of most cellular materials and solid foams have a char acteristic sigmoid shape that reflects three deformation mechanisms: primarily elastic distortion under small strains; collapse and/or fracture of cell walls; and densification. The exact shape of the relationship is mainly determined by the materials' composition including: moisture contents; the cells and cell wall size and geometry; and whether the cells are open or closed. Upon repeated compression the nature of the relationship may change as a result of irreversible changes in the solid matrix (especially rupture). When the cell wall material is very brittle the force-displacement curve can be extremely irregular and jagged, often concealing its underlying sigmoid shape. Characterization of such brittle products requires methods of jaggedness evaluation and smoothing procedures. These are now readily available and have been successfully applied to extruded puffed foods. Food particulates tested in bulk can show similar compressibility patterns even if they themselves do not have a cellular structure. Although tensile properties of spongy baked foods, like bread crumbs, can be determined experimentally they have not yet been proven useful as indicators of textural quality, primarily as it appears, because of structural non-uniformity.

Lubricated squeezing flow viscometry for dulce de leche (milk sweet) Viscometría de extensión biaxial sin fricción de dulce de leche

Commercial samples of dulce de leche (milk sweet, caramel jam) of two types, made by two different manufacturers were squeezed between two parallel Teflon® plates, 64 mm in diameter. The initial height of the samples was about 8 mm and they were compressed to 0.4 mm at rates of 0.1, 0.2, 0.3 and 0.4 mm/s. After the samples had reached the final height, they were allowed to relax for about 3 min. The force-height relationships, when plotted on logarithmic coordinates, had a clearly discern ible linear region, with slope in the range of -1.1 to -1.5. The apparent stress at pre-selected heights was used as a measure of the product consistency. The experimental scatter of these stresses was in the order of the 10%, small enough to detect differences between the different brands and monitor rate effects. The latter did not conform to theoretical predictions based on the power law model, most probably because of the products' considerable apparent yield stress on the experimental time scale. An empirical formula to describe the rate effect was developed and found to be appropriate for all the products tested. The yield stress itself was manifested in the magnitude of the residual stress after relaxation. It could also be used as a measure of consistency which provided the same ranking of the samples as the apparent stress at a fixed height.

Effect of Moisture on the Mechanical Properties of Pork Rind (Chicharrón)

Pork rind particles of two commercial brands were tested at various water activity levels in the range of 0.1-0.8 and compressed as shallow bed using an Instron universal testing machine. The jaggedness of the resulting force-displacement curves was determined in terms of their apparent Richardson and Kolmogorov fractal dimension and the mean magnitude of their power spectrum after normalisation. The bed's stiffness was assessed in terms of the compressive force at 25 and 35% displacement. The jaggedness decrease, which corresponds to brittleness loss, took place around the water activity of 0.5 with a span of about 0.2. Sorption at levels up to about 0.5 was accompanied by `moisture toughening' that is the bed's stiffness measures increased with aw. There was a sharp decline at higher water activity levels as the structure collapsed. The changes in the brittleness and stiffness parameters as a result of moisture sorption were modelled with the Fermi and a combination of Fermi and the logistic equations, respectively.

The Use of Tilted Implant for Posterior Atrophic Maxilla

PURPOSE

To retrospectively analyze the influence of implant inclination on marginal bone loss at freestanding implant-supported fixed partial prostheses (FPPs) over a medium-term period of functional loading.

MATERIALS AND METHODS

Twenty-nine partially edentulous patients with freestanding FPDs supported by two implants placed in a two-stage procedure comprised the study group. The anterior implant was placed axially, and the posterior tilted distally. Mesial or distal inclination of each implant was measured in relation to the vertical axis perpendicular to the occlusal plane. Average bone loss was compared between straight and tilted implants, smokers, and nonsmokers.

RESULTS

Mean angulation of the anterior axial-positioned implant was 3.45 degrees distally (range 0-8) and of the distal implants was 32.83 degrees distally (range 20-50 degrees). Average bone loss after 1, 3, and 5 years was 0.89 (SD = 0.73), 1.18 (SD = 0.74), and 1.50 (SD = 0.81), respectively, for axial implants, and 0.98 (SD = 0.69), 1.10 (SD = 0.60) and 1.50 (SD = 0.67) for tilted implants, with no significant correlation between implant angulation and bone loss. A significant correlation between implant angulation and annual bone loss was obtained for tilted implants only (r = 0.52, p = .004).Using Albrektsson criteria, the success rate was 89.6% (26 out of 29 implants) for straight and 93.1% (27 out of 29) for tilted implants.

CONCLUSION

The study demonstrates no effect of implant angulation on peri-implant bone loss in the posterior maxilla.

Discussion of "Attitude of physicians towards automatic alerting in computerized physician order entry systems"

With these comments on the paper "Attitude of Physicians Towards Automatic Alerting in Computerized Physician Order Entry Systems", written by Martin Jung and co-authors, with Dr. Elske Ammenwerth as senior author [1], the journal wants to stimulate a broad discussion on computerized physician order entry systems. An international group of experts have been invited by the editor of Methods to comment on this paper. Each of the invited commentaries forms one section of this paper.

Use of corticocancellous allogeneic bone blocks for augmentation of alveolar bone defects

PURPOSE

The use of autogenous block bone grafts in bone regeneration procedures for alveolar ridge augmentation can be limited by donor site morbidity and complications. The purpose of the present study was to evaluate the efficacy of allogeneic corticocancellous iliac block grafts used for ridge augmentation prior to implant placement.

MATERIALS AND METHODS

Forty-one patients with severe ridge volume deficiency underwent augmentation using allogeneic corticocancellous iliac block bone grafts. After rigid fixation of the graft, the site was covered with a freeze-dried allogeneic dura mater membrane, and the wound was closed with tension-free suturing. Implants were placed 3 to 4 months after surgery. Three to 6 months after implant placement, panoramic radiographs were taken and implants were uncovered for prosthetic restoration.

RESULTS

Of the 57 grafts placed, one showed 2.5 mm of resorption at the superior buccal aspect of the graft. No other clinical problems were observed. The block grafts were clinically well integrated into the recipient sites and the augmented bone remained stable throughout the implant placement procedures. Of the 84 implants placed, only one failed to integrate.

CONCLUSION

These results demonstrate that the use of allogeneic corticocancellous iliac block bone grafts in conjunction with guided bone regeneration principles is a viable alternative to autogenous grafts in selected patients with alveolar ridge deficiencies.

Primary Diffuse Large Cell Lymphoma of the Mandible

Primary diffuse large cell lymphoma of the mandible is a rare form of extranodal non-Hodgkin's lymphoma (NHL). Herein we present 4 cases treated at our institution over a 5-year period and review 40 cases previously reported in the English-literature. The median age at presentation is 51 years with equal distribution between males and females. At presentation the lymphoma is usually limited to the jaw (stage IE) and the most common presenting symptoms include swelling of the jaw (58%), pain (53%), and mental dysesthesia or numbness (20%). Despite symptoms of numb chin syndrome, central nervous system (CNS) involvement at presentation has not been reported. The reported therapy of this rare diffuse large cell lymphoma presentation is very heterogeneous, however majority of patients were treated with combination of chemotherapy and radiotherapy with estimated 5-year overall survival of only 60%. Multi-center prospective clinical trials are needed to determine the optimal therapeutic approach to this rare diffuse large cell lymphoma presentation.

[Alveolar ridge augmentation with hip corticocancellous allogenic block graft prior to implant placement]

The use of autogenous block bone grafts in bone regeneration procedures for alveolar ridge augmentation can be limited by donor-site morbidity and complications. In this study, allogeneic block grafts were used for ridge augmentation prior to implant placement. Thirty six patients with severe ridge width and height deficiency underwent augmentation using an allogeneic corticocancellous iliac block bone graft. After rigid fixation of the graft, the site was covered with a freeze dried allogeneic dura mater membrane or restorable collagen membrane and then tension-free closure was performed. Implants were placed three to four months after surgery. Three to six months after implant placement, panoramic radiographs were taken and implants were uncovered for prosthetic restoration. Out of the 70 implants placed, one implant failed to integrate. Out of the 49 grafts placed one graft showed three millimeters of bone resorbtion at the superior buccal aspect of the graft. No other clinical problems were observed. The block grafts were clinically well integrated into the recipient site. The augmented bone remained stable throughout implant placement procedures. Clinical outcome evidence demonstrates that allogeneic block bone grafts in conjunction with G.B.R principles might be a viable alternative to autogenous grafts in selected patients with alveolar ridge deficiencies.

Section 5: Decision Support, Knowledge Representation and Management: Decision Support, Knowledge Representation and Management in Medicine

Clinical decision-support systems (CDSSs) are being recognized as important tools for improving quality of care. In this paper, we review the literature to find trends in CDSSs that were developed over the last few decades and give some indication of future directions in developing successful, usable clinical decisionsupport systems.

We searched PubMed for papers that were published during the past five years with the words Decision Support Systems appearing in the title and used our own knowledge of the field for earlier work.

The goals of developers of modern CDSSs are to develop systems that deliver needed information and could be integrated with the healthcare’s organizational dynamics. Such CDSSs form part of knowledge-management activities that healthcare organizations employ in order to excel. During the past few decades, we have witnessed a gradual maturation of knowledge representation formalisms and the needed infrastructure for developing integrated CDSSs, including electronic health record systems (EHR), standard terminologies, and messaging standards for exchange of clinical data. The demand for CDSSs that are effective and that will evolve as circumstances change gave rise to methodologies that guide developers on the construction and evaluation of CDSSs.

Although there exist many approaches for representing, managing and delivering clinical knowledge, the design and implementation of good and useful systems that will last and evolve are still active areas of research. The gradual maturation of EHR and infrastructure standards should make it possible for CDSSs implementers to make major contributions to the delivery of healthcare.

Healing in smokers versus nonsmokers: survival rates for sinus floor augmentation with simultaneous implant placement

PURPOSE

Evidence suggests that smoking is detrimental to the survival of dental implants placed in grafted maxillary sinuses. Studies have shown that improving bone quantity and quality, using rough-surfaced implants, and practicing good oral hygiene may improve outcomes. In this prospective study, the long-term survival rates of implants placed simultaneously with sinus grafting in smokers and nonsmokers were compared.

MATERIALS AND METHODS

Implants with roughened surfaces were immediately placed into maxillary sinus grafts in patients with 1 to 7 mm of residual bone. A total of 2132 simultaneous implants were placed into the grafted sinuses of 226 smokers (627 implants) and 505 nonsmokers (1505 implants). A majority of the patients received a composite graft consisting of 50% autogenous bone. In both smokers and nonsmokers, approximately two thirds of the implants had microtextured surfaces; the remainder had hydroxyapatite-coated surfaces. The implants were restored and monitored during clinical follow-up for up to 9 years.

RESULTS

Cumulative survival of implants at 9 years was 97.9%. There were no statistically significant differences in implant failure rates between smokers and nonsmokers.

DISCUSSION

Implant survival was believed to depend on the following aspects of the technique used: creation of a large buccal window to allow access to a large recipient site; use of composite grafts consisting of at least 50% autogenous bone; meticulous bone condensation; placement of long implants (i.e., 15 mm); use of implants with hydroxyapatite-coated or microtextured surfaces; use of a membrane to cover the graft and implants; antibiotic use and strict oral hygiene; use of interim implants and restricted use of dentures; and adherence to a smoking cessation protocol.

Decision support, knowledge representation and management in medicine

OBJECTIVES

Clinical decision-support systems (CDSSs) are being recognized as important tools for improving quality of care. In this paper, we review the literature to find trends in CDSSs that were developed over the last few decades and give some indication of future directions in developing successful, usable clinical decision-support systems.

METHODS

We searched PubMed for papers that were published during the past five years with the words Decision Support Systems appearing in the title and used our own knowledge of the field for earlier work.

RESULTS

The goals of developers of modern CDSSs are to develop systems that deliver needed information and could be integrated with the healthcare's organizational dynamics. Such CDSSs form part of knowledge-management activities that healthcare organizations employ in order to excel. During the past few decades, we have witnessed a gradual maturation of knowledge representation formalisms and the needed infrastructure for developing integrated CDSSs, including electronic health record systems (EHR), standard terminologies, and messaging standards for exchange of clinical data. The demand for CDSSs that are effective and that will evolve as circumstances change gave rise to methodologies that guide developers on the construction and evaluation of CDSSs.

CONCLUSION

Although there exist many approaches for representing, managing and delivering clinical knowledge, the design and implementation of good and useful systems that will last and evolve are still active areas of research. The gradual maturation of EHR and infrastructure standards should make it possible for CDSSs implementers to make major contributions to the delivery of healthcare.

Predictability of simultaneous implant placement in the severely atrophic posterior maxilla: A 9-year longitudinal experience study of 2132 implants placed into 731 human sinus grafts

PURPOSE

One-stage implant placement in the grafted maxillary sinus has traditionally been limited to patients with at least 5 mm of residual bone to ensure complete implant stabilization. The aim of this prospective study was to determine the long-term survival rates of implants with roughened surfaces placed immediately into maxillary sinus grafts in patients with 1 to 5 mm of residual bone.

MATERIALS AND METHODS

A total of 2132 microtextured screw-type (n=1374) or hydroxyapatite-coated cylinder-type (n=758) implants were immediately placed into the grafted sinuses of 731 patients. The implants were restored and monitored for up to 9 years of clinical follow-up.

RESULTS

Cumulative survival at 9 years was 97.9% (n=2091 implants); 20.4% of the implants were placed in 1 to 2 mm of residual bone.

DISCUSSION

Initial implant stability and parallelism were achieved through a combination of meticulous condensation of the particulate bone graft material around the implants, the frictional interface of the roughened implant surfaces and the host tissues, and selection of an appropriate graft material.

CONCLUSIONS

Simultaneous implant placement into sinus floor grafts can be a predictable treatment option for patients with at least 1 to 2 mm of vertical residual bone height when careful case planning and meticulous surgical techniques are used.

Estimating non-isothermal bacterial growth in foods from isothermal experimental data

AIM

To develop a mathematical method to estimate non-isothermal microbial growth curves in foods from experiments performed under isothermal conditions and demonstrate the method's applicability with published growth data.

METHODS AND RESULTS

Published isothermal growth curves of Pseudomonas spp. in refrigerated fish at 0-8 degrees C and Escherichia coli 1952 in a nutritional broth at 27.6-36 degrees C were fitted with two different three-parameter 'primary models' and the temperature dependence of their parameters was fitted by ad hoc empirical 'secondary models'. These were used to generate non-isothermal growth curves by solving, numerically, a differential equation derived on the premise that the momentary non-isothermal growth rate is the isothermal rate at the momentary temperature, at a time that corresponds to the momentary growth level of the population. The predicted non-isothermal growth curves were in agreement with the reported experimental ones and, as expected, the quality of the predictions did not depend on the 'primary model' chosen for the calculation.

CONCLUSIONS

A common type of sigmoid growth curve can be adequately described by three-parameter 'primary models'. At least in the two systems examined, these could be used to predict growth patterns under a variety of continuous and discontinuous non-isothermal temperature profiles.

SIGNIFICANCE AND IMPACT OF THE STUDY

The described mathematical method whenever validated experimentally will enable the simulation of the microbial quality of stored and transported foods under a large variety of existing or contemplated commercial temperature histories.

Generating microbial survival curves during thermal processing in real time

AIMS

To develop a method to calculate and record theoretical microbial survival curves during thermal processing of foods and pharmaceutical products simultaneously with the changing temperature. Moreover, to demonstrate that the method can be used to calculate nonisothermal survival curves, with widely available software such as Microsoft Excel.

METHODS AND RESULTS

It has been assumed that the targeted organism's isothermal survival curves are not log linear and hence, the inactivation rate in nonisothermal processes is a function of the momentary temperature and the corresponding survival ratio. This could be expressed by a difference equation, which is an approximation to the continuous rate model. The concept was tested with the isothermal survival parameters of Clostridium botulinum and Bacillus sporothermodurans spores, and Salmonella enteritidis cells, using different kinds of survival models and under temperature profiles resembling those of commercial processes. As expected, there was an excellent agreement between the curves produced by solving the differential equation of the continuous model and by the incremental method, which has been posted on the web as freeware.

CONCLUSIONS

It is possible to calculate nonisothermal survival curves, in real time, with an algorithm that can be written in the language of general purpose software, to follow the inactivation of one or more targeted organisms simultaneously and to simulate microbial survival patterns under existing or planned industrial thermal processes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Replacement of the traditional 'F0-value', which requires the log linearity of the organism's isothermal survival curves, by the more realistic theoretical survival ratio estimate as a measure of the thermal process efficacy.

Maxillary sinus and ridge augmentations using a surface-derived autogenous bone graft

PURPOSE

The purpose of this article is to describe a new technique and the anatomic sites for cutting and harvesting bone for grafting applications. A handheld instrument is described that cuts and collects thin shavings of bone from cortical surfaces.

MATERIALS AND METHODS

This study included 193 consecutive patients who needed bone augmentation and simultaneous implant placement in the severely atrophic posterior maxilla and in the anterior maxilla with acquired defect of alveolar bone as a result of local trauma. A total of 477 implants were placed. Clinical criteria for evaluation at time of implant exposure included stability in all directions, crestal bone resorption, and any reported pain of discomfort.

RESULTS

There were no failures of the anterior maxilla group, and no signs of bone resorption were noted at the second stage surgery or during the follow-up. During initial and late healing, there was no dehiscence of the soft tissue flaps and no membranes were exposed. Core biopsies typically showed immature, newly formed bone and, on average, 27% to 36% vital bone.

CONCLUSION

From this research, it appears that excellent implant success rates can be achieved in grafted sinuses or ridges when a locally harvested autogenous bone graft with a ribbon geometry is used.

Estimation of the non-isothermal inactivation patterns of Bacillus sporothermodurans IC4 spores in soups from their isothermal survival data

The isothermal survival curves of the heat resistant spores of Bacillus sporothermodurans IC4, in the range of 117-125 degrees C, were determined in chicken, mushroom and pea soups by the capillary method. They were all non-linear with a noticeable upper concavity and could be described by the equation log(10) [N(t)/N(0)]=-b(T)t(n) with a fixed power, n, of the order of 0.7-0.8. The temperature dependence of b(T) could be described by the equation b(T)=log(e)[1+exp[k(T-T(c))]], where T(c) is the temperature where intensive inactivation starts and k is the slope of b(T) at temperatures well above T(c). They were 121-123 degrees C and 0.2-0.4 degrees C(-1), respectively, depending on the soup. These parameters were used to estimate the survival curves of the spores in two non-isothermal heat treatments using the procedure originally proposed by Peleg and Penchina [Crit. Rev. Food Sci. Nutr. 40 (2000) 159]. The results were compared with experimental survival curves, determined by the direct injection method, in another laboratory. There was a general agreement, although not perfect, between the predicted and experimentally observed survival ratios. Also, the isothermal survival parameters, estimated directly from the non-isothermal inactivation data using the model, were in general agreement with those calculated from the isothermal data. This suggests that the heat inactivation patterns of B. sporothermodurans IC4 spores in soups can be at least roughly estimated using the same general survival model, which has until now only been experimentally validated for vegetative bacterial cells.

Platelet-rich plasma for bone graft enhancement in sinus floor augmentation with simultaneous implant placement: patient series study

The use of autologous platelet-rich plasma (PRP) as a source for growth factors in bone grafting is a relatively new and promising technique. Early controlled studies indicate that combining PRP with autologous bone grafts significantly enhances the rate of bone formation and maturation. The study consisted of 105 patients who required sinus augmentation with crestal bone height of less than 5 mm in the posterior maxilla. All patients received a composite bone graft that consisted of 30% to 40% autogenous bone harvested from the lateral wall of the maxilla zygomatic-maxillary buttress and the tuberosity and 60% to 70% xenograft. A total of 50 mL of blood was obtained from each patient before the surgical treatment for preparation of 10 mL of PRP. The graft-PRP mixture was activated by human thrombin. All sinus augmentations were carried out simultaneously with dental implants. At 6 months postoperatively, implants were exposed showing no clinical evidence of crestal bone loss around the implants both clinically and radiographically. All implants were clinically osseointegrated and loaded with fixed porcelain fused to metal prosthesis. The use of PRP in augmenting the severely atrophic posterior maxilla has obvious clinical benefits in terms of reducing the healing period of bone maturation, better graft handling, and accelerated soft tissue healing.

A model of microbial survival curves in water treated with a volatile disinfectant

AIM

To develop a method to calculate microbial survival parameters in water treated with a dissipating disinfectant and predict the inactivation patterns under different agent concentrations and decay rate regimes.

METHODS AND RESULTS

It has been assumed that the survival curves of the organism, under (hypothetical) constant agent concentration conditions, follow the power law model log [N(t)/N0] = -btn with a concentration independent exponent, n. The concentration dependence of the 'rate parameter', b, has been assumed to obey a log logistic relationship. Under changing disinfectant concentration, the survival curve is constructed so that its local slope, i.e. momentary logarithmic inactivation rate of the organism, is the slope of the momentary 'constant concentration' curve at the momentary agent concentration, at the time which corresponds to the momentary survival ratio. The resulting differential equation was used to retrieve the survival parameters by numerical minimization procedures. Once these are calculated, the equation is solved numerically to produce the survival curve for almost any conceivable agent concentration history. The predictive ability of the method is demonstrated by using the survival parameters, calculated from published data obtained under one concentration profile, to predict survival curves under very different decay patterns.

CONCLUSIONS

It is possible to calculate microbial survival parameters from data obtained in treatments where the unstable or volatile disinfectant progressively dissipates and use them to predict the outcome of different treatments.

SIGNIFICANCE AND IMPACT OF THE STUDY

The proposed mathematical method will enable the prediction of microbial inactivation patterns in water treated with unstable and/or volatile chemical agents.

Amputation neuromas after neck dissection

OBJECTIVE

We sought to define the incidence of neuroma formation after neck dissection in a large series of patients.

METHODS

One hundred fifty-three patients who were seen during a 2-year period (followed for 3 months to 10 years; mean, 52 months) were evaluated for neuroma formation after neck dissection (185 procedures). Cut nerve edges were not routinely ligated or cauterized.

RESULTS

Operative records indicated that except for 4 cases, the stumps of the great auricular nerve and cervical branches were left intact after resection. No cases of palpable neuromas were found. In one case of a revised neck, a small macroscopically indiscernible nodule was histologically defined as neuroma.

CONCLUSION

No neuromas were discovered in our series of neck dissection cases. If found, it is imperative these lesions be differentiated from recurrent cancer. Our results do not support any interference with cut nerve edges.

Syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion in patients following neck dissection

OBJECTIVES/HYPOTHESIS

The syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion (SIADH) is a disorder in which release of antidiuretic hormone is independent of plasma osmolarity, resulting in fluid retention and development of dilutional hyponatremia. The incidence of SIADH following neck dissection was found to be 18% to 30% in two separate reports. The incidence of SIADH in a cohort of patients who underwent neck dissection was prospectively studied.

METHODS

Eighty-six patients were included in the study, along with a control group of 19 patients who underwent other neck procedures. Patient gender, age, physical condition (American Society of Anesthesiologists score), type of neck dissection, prior treatment, and smoking history were noted. Blood and urine osmolarity and sodium levels were sampled before surgery and during the first 24 hours after the surgery. These were recorded daily in cases with SIADH until the syndrome resolved.

RESULTS

The incidence of SIADH was only 1.15% in patients before surgery. The syndrome developed in seven patients following neck dissection (8.14%) and in none of the patients in the control group. SIADH resolved within 72 hours at the latest. No association was found with patient gender, age, physical condition, or type or laterality of neck dissection. A statistically significant connection between the syndrome and history of smoking was noted (P <.05), and it was more commonly seen in patients with node-positive necks (P =.1231).

CONCLUSIONS

SIADH following neck dissection may be less common than formerly reported. Previous studies have presented contradicting data concerning the influence of tumor recurrence or prior radiation therapy on its incidence. Our results indicate no such association. A statistically significant connection between smoking and the syndrome was found. No clinical symptoms developed in the patients with SIADH, but it seems prudent to suggest limiting fluid intake in the first postoperative 24 hours for patients following neck dissection.