3D planning of ear prosthesis and navigated flapless surgery for craniofacial implants: A pilot study.

New 3D digital technologies can be applied to implant-supported ear prostheses to restore anatomical structures damaged by cancer, dysplasia, or trauma. However, several factors influence the accuracy of implant positioning using a cranial template. This pilot study describes an innovative navigated flapless surgery for craniofacial implants, prosthetically guided by 3D planning of the ear prosthesis. Laser surface scanning of the face allowed for mapping of the healthy ear onto the defect site, and projection of the volume and position of the final prosthesis. The projected ear volume was superimposed on the skull bone image obtained by cone-beam computed tomography (CBCT), performed with the navigation system marker plate positioned in the patient's mouth. The craniofacial implants were fitted optimally to the ear prosthesis. After system calibration, real-time navigated implant placement based on the virtual planning was performed with minimally invasive flapless surgery under local anesthesia. After 3 months of healing, digital impressions of the implants were made, and the digital manufacturing workflow was completed to manufacture the ear prosthesis anchored to the craniofacial implants. The proposed digital method facilitated implant positioning during flapless surgery, improving the ear prosthesis manufacturing process and reducing operation time, patient morbidity, and related costs. This protocol avoids the need for a reference tool fixed in the cranial bone, as is usually required for maxillofacial surgery, and confirmed that surgical navigation is useful for guiding the insertion of craniofacial implants during flapless surgery.

[State of the art and scientific evidence on the role of unidirectional airflow ventilation systems in reducing surgical site infections]. / Stato dell'arte ed evidenze scientifiche sul ruolo dei sistemi di ventilazione a flusso unidirezionale nella riduzione delle infezioni del sito chirurgico.

The use of unidirectional airflow ventilation systems in operating rooms is frequently recommended for the prevention of Surgical Site Infections (SSI). However, scientific evidence is lacking to clearly support this technology which entails high investment costs and operating expenses, as compared with traditional ventilation systems. This sparse evidence is mainly related to the small number of interventions analyzed in each study and the difficulty to distinguish the effects of ventilation and other important confounding factors, such as antibiotic prophylaxis, special operating staff clothing and adoption of educational and training programs against SSI for the surgical personnel. The different behavior of the industrialized countries towards this issue, as it comes out analyzing the existing Rules and Guidelines concerning operating rooms ventilation, reflects a precautionary approach towards a technology which, until recently, has clearly demonstrated neither benefits nor limitations. In 2008, a relevant scientific study was published, reporting results from 63 departments of 55 German hospitals for a total of 99.230 surgical interventions, in which a standardized SSI surveillance was performed. Unexpectedly, the study concluded that unidirectional airflow ventilation showed no benefit and was even associated with a significantly higher risk for severe SSI, as compared with turbulent clean air. The present review collects updates from the scientific literature and national and international Rules and Guidelines concerning the use of unidirectional airflow ventilation systems in operating rooms, analyzing all aspects involved in this issue, from the debated efficacy of these systems in reducing the incidence of SSI to the "side effects" associated to their use, as the relevant costs and the reduction of the environmental comfort for the operators.

A new hermetic antenna for wireless transmission systems of implantable medical devices.

In implantable medical devices (IMDs), the need of telemetry systems able to provide wireless bidirectional communication to interrogate and remotely program the device, as well as to monitor the physiological status of the patient, is growing. The object of the present study was to evaluate a new hermetic antenna for wireless short-range transmission system for IMDs which would assure reliable long-term functioning due to the high level of hermeticity of antenna's housing that limits the influence of body tissue environment on transmitted signals. Experimental tests were conducted on three different prototypes to evaluate the most efficient antenna configuration for transmission both in the air and through a mixture simulating the human thorax. Further tests were performed to assess the influence of electro-catheters connected to IMDs on transmitted signals. Results showed that the hermetic antenna guarantees a good wireless transmission both in the air and through the human thorax simulator. The results also show that the presence of an electro-catheter can influence the effective radiated power (ERP) transmitted depending on its position in relation to the telemetric circuitry. Both a controlled increase of the ERP without exceeding the limits imposed by rules and the optimization of the tuning between the antenna and the transmitter can assure a reliable short-range transmission (several meters) using the new hermetic antenna proposed.

[Cost evaluation of a ventilation system for operating theatre: an ultraclean design versus a conventional one]. / Valutazione dei costi di un impianto di ventilazione per un blocco operatorio: confronto tra sistema "ultraclean" e convenzionale.

The postoperative infection has been recognized as a critical problem in healthcare, increasing patients'complications and hospitalization costs. At the moment the scientific evidence clearly linking ventilation parameters, such as air changes per hour, bacterial counts and infection, is lacking, with the exception of prosthetic joint surgery. This study aims to evaluate the building and operating costs of an ultraclean system versus a conventional one (which satisfies the minimum performance requested by rules), also considering the debating efficacy of ultraclean ventilation on prevention of postoperative infection. The results of our study show an increase of 24% in the building costs and of 34% in the annual operating costs for the ultraclean system versus the conventional one. The estimated 24% increase of the building costs for the ultraclean ventilation system represents only a 5% increase if compared to the total cost of a not equipped operating theatre. Therefore, the increase on costs linked to the use of high performance ventilation facilities seems to be so small that overcoming current rules towards ultraclean systems could be acceptable.

Considerations on isolation rooms and alternative pressure ventilation systems.

The health-care facility environment is involved in disease transmission in essentially two different situations: 1. in cases where patients are immunocompromised and require protection from infections; 2. in cases of inadvertent exposure to environmental or airborne pathogens that can aggravate patients' existent disease and cause illness among health-care personnel. Environmental infection-control strategies and engineering controls can effectively prevent transmission of these infections. In particular the ventilation system is fundamental to the control of the concentration of airborne contaminants within a hospital isolation room because it establishes and maintains appropriate pressure differentials within special care areas of the building. Thus the incidence of health-care-associated infections can be minimized by adherence to ventilation standards suggested in the guidelines for specialized care environments such as Airborne Infection Isolation rooms (AII, as in situation 2 above), and Protective Environments (PE) rooms (as in situation 1 above). This report is a comparative review of the principal guidelines and strategies existing in the international scientific literature for the prevention of environment-associated infections in healthcare facilities using pressure differentials (positive pressure for PE rooms, negative pressure for AII rooms). The purpose of the review is also to investigate the state-of-the-art use of the "alternative pressure rooms", i.e., areas furnished with a ventilation system capable of switching pressure from positive to negative according to patients' needs. The results of the present analysis indicate an unenthusiastic reaction to these "alternative pressure rooms", although there is no scientific evidence against their use.

PEA I and PEA II based implantable haemodynamic monitor: pre clinical studies in sheep.

AIMS: The aims of this study were first, to demonstrate that Peak Endocardial Acceleration during isovolumic systole (PEA I) is related to positive peak LVdP/dt, while Peak Endocardial Acceleration during isovolumic relaxation time (PEA II) is related to aortic diastolic pressure (ADP) and to negative peak LVdP/dt; and second, to test if the simultaneous recording of PEA I and PEA II offers a new chance to monitor indexes of LV systolic and diastolic function. METHODS: An implantable haemodynamic monitor, based on PEA I and PEA II measurements via a microaccelerometer sensor located in the tip of a pacing lead, screwed into the right ventricle, was tested in nine sheep at baseline and during acute haemodynamic interventions: nitrate (0.1 mg/ kg), metaraminol (0.15 mg/kg), dobutamine (5 microg/kg) infusion. ADP, positive and negative peak LVdP/dt were simultaneously recorded by an aortic and left ventricular Millar catheter. RESULTS: PEA I changes were significantly related to positive peak LVdP/dt changes during dobutamine induced inotropic changes (r = 0.83, P < 0.001). PEA II changes were significantly related to both ADP (r = 0.91, P < 0.001) and negative peak LVdP/dt changes (r = 0.92, P < 0.001) during nitrate induced hypotension and metaraminol induced hypertension. CONCLUSION: The simultaneous recording of PEA I and PEA II with an implantable system offers a new chance to monitor indexes of LV systolic and diastolic function.

Are macrophages involved in early myocardial reperfusion injury?

BACKGROUND: Neutrophils are the predominant phagocytes in the early stages of myocardial ischemia-reperfusion response and are also implicated in the development of tissue damage. This study examined the role of recruited macrophages in the evolution of this tissue injury. METHODS: Farm pigs were subjected to 30 minutes of myocardial ischemia followed by 30 minutes of reperfusion. Biopsy samples were taken from the control, ischemic, and ischemic-reperfused left ventricle wall and processed for both morphologic and biochemical analyses. In situ production of tumor necrosis factor-alpha was evaluated by Western blot and immunofluorescence. A full hemodynamic evaluation was also performed. RESULTS: Myocardial ischemia and early reperfusion caused marked neutrophil and macrophage tissue accumulation and tumor necrosis factor-alpha production by the injured tissue. Immunofluorescence studies allowed us to localize tumor necrosis factor-alpha predominantly in tissue-infiltrating macrophages. No depression in the global myocardial contractile function was observed, either during ischemia or after reperfusion. CONCLUSIONS: These data suggest that the newly recruited macrophages within the ischemic and early post-ischemic myocardium may play a role in promoting neutrophil tissue infiltration and subsequent neutrophil-induced tissue dysfunction by producing tumor necrosis factor-alpha.

Operator independent left ventricular function monitoring during pharmacological stress echo with the new peak transcutaneous acceleration signal.

BACKGROUND: As the myocardium contracts isometrically, it generates vibrations that can be measured with an accelerometer. The vibration peak, peak endocardial acceleration (PEA), is an index of contractility. OBJECTIVE: To evaluate the feasibility of PEA measured by the cutaneous precordial application of the accelerometer sensor; and to assess the usefulness of PEA monitoring during pharmacological stress echocardiography. DESIGN: Feasibility study. SETTING: Stress echo laboratory. PATIENTS: 34 consecutive patients underwent pharmacological stress (26 with dipyridamole; 8 with dobutamine) and PEA monitoring simultaneously. INTERVENTIONS: A microaccelerometer was positioned in the precordial region and PEA was recorded. Dipyridamole was infused up to 0.84 mg/kg in 10 minutes, and dobutamine up to 40 microg/kg/min in 15 minutes. RESULTS: A consistent PEA signal was obtained in all patients. Overall mean (SD) baseline PEA was 0.26 (0.15) g (g = 9.8 m/s(2)), increasing to 0.5 (0.36) g at peak stress (+0.24 g, 95% confidence interval (CI) 0.14 to 0.34 g; p < 0.01). PEA increased from 0.26 (0.16) to 0.37 (0.25) g in the dipyridamole group (+0.11 g, 95% CI 0.08 to 0.16 g; p < 0.01), and from 0.29 (0.1) to 0.93 (0.37) g in the dobutamine group (+0.64 g, 95% CI 0.37 to 0.91 g; p < 0.01). CONCLUSIONS: Using precordial leads this method offers potential for diagnostic application in the short term monitoring of myocardial function. PEA monitoring is feasible during pharmacological stress and documents left ventricular inotropic response quantitatively in a non-invasive and operator independent fashion.

Peak endocardial acceleration reflects heart contractility also in atrial fibrillation.

Previous studies demonstrated that peak endocardial acceleration (PEA) in sinus rhythm is related to LV dP/dtmax. Until now, PEA was never evaluated during R-R interval variations in AF. The aim of this study was to establish the behavior of PEA in AF and the relationship of PEA versus LV dP/dtmax. Six sheep (65 +/- 6 kg) were instrumented with a LV Millar catheter and with an accelerometer lead. AF was induced and PEA, LV dP/dtmax, and ECG were monitored. AF persisted for 5 +/- 1.3 minutes. From sinus rhythm to AF, the heart rate went from 92 +/- 3 to 130 +/- 35 beats/min (P < 0.05), LV dP/dtmax from 684 +/- 18 to 956 +/- 344 mmHg/s (P = NS) and PEA from 0.82 +/- 0.06 to 0.94 +/- 0.33 g (P = NS). The correlation between PEA and LV dP/dtmax was significative in sinus rhythm (r = 0.7, P < 0.05) and in AF (r = 0.8, P < 0.05). A positive relationship was found between the preceding interval and PEA (r = 0.4 +/- 0.07, P < 0.05) and LV dP/dtmax (r = 0.61 +/- 0.08, P < 0.05), while a negative one was found between the prepreceding interval and both PEA (r = -0.39 +/- 0.11, P < 0.05) and LV dP/dtmax (r = -0.64 +/- 0.05, P < 0.05). At the onset of AF, LV dP/dtmax and PEA showed similar changes: beat-to-beat correlation between PEA and LV dP/dtmax was high. As for LV dP/dtmax, PEA is positively related to the preceding interval and negatively related to the prepreceding interval. These data confirm that PEA reflects heart contractility also during AF and hold promise for the use of this sensor in therapeutic implantable devices.

Achilles allograft reconstruction of a chronic patellar tendon rupture.

Chronic ruptures of the patellar tendon are uncommon injuries. They are technically difficult to repair because of scar formation, poor quality of the remaining tendon, and quadriceps muscle atrophy and contracture. We report the reconstruction of a chronic patellar tendon rupture with an interesting complication, a tibial stress fracture. The reconstruction was performed 3 months after the injury using an Achilles tendon-bone allograft and reinforcing suprapatellar wire. At 2 weeks postoperatively, the patient had attained full extension and 90 degrees of flexion. Ten months after the index procedure, the patient had range of motion 0 degrees to 120 degrees and was diagnosed with a healing tibial stress fracture. At 17 months postoperatively, the patient had attained full extension, 120 degrees of flexion, and 85% quadriceps strength. The preoperative goals of attaining full range of motion, improving quadriceps strength, obtaining anatomic patellar alignment, and restoring function were obtained despite the complication of a tibial stress fracture. Although this reconstructive procedure is technically demanding, with potential complications, the functional results obtained can be excellent.

The unauthorized Mexican immigrant population and welfare in Los Angeles County: a comparative statistical analysis.

"Using a unique 1994 Los Angeles County Household Survey of foreign-born Mexicans and the March 1994 and 1995 Current Population Surveys, we estimate the number of unauthorized Mexican immigrants (UMIs) residing in Los Angeles County, and compare their use of seven welfare programs with that of other non-U.S. citizens and U.S. citizens. Non-U.S. citizens were found to be no more likely than U.S. citizens to have used welfare, and UMIs were 11% (14%) less likely than other non-citizens (U.S.-born citizens).... We demonstrate how results differ depending on the unit of analysis employed, and on which programs constitute ¿welfare'."

Unauthorized Mexican workers in the 1990 Los Angeles County labour force.

"By analysing how unauthorized Mexicans compare with seven other ethno-racial groups in Los Angeles County, separately and collectively, by educational attainment and time spent in the U.S., we find that unauthorized Mexicans had relatively fewer years of formal education (either in the U.S. or in Mexico) and had been in the U.S. a relatively fewer number of years than in-migrants of other ethno-racial backgrounds in 1990. These findings are then used as proxies to compare the human capital endowments of different ethno-racial groups. We next estimate the number of unauthorized Mexicans by occupation, industry and class of worker, and compare these distributions with the total labour force and with the other ethno-racial groups in Los Angeles County.... Results show that amounts of human capital are positively related to the kinds of occupations filled." (SUMMARY IN FRE AND SPA)

Ender nail fixation in long bone fractures: experience in a level I trauma center.

Early fixation of extremity fractures in polytrauma patients is a well accepted and desirable treatment. In our patient population, the indications for immediate Ender nail fixation was for Grade I and Grade II open long bone fractures and closed long bone fractures in patients with small intramedullary canals. Ender nails were also used in patients in whom reaming was undesirable. This included patients with open physes for immediate fracture fixation and in those with Grade III open wounds in a delayed fashion. These flexible nails were also implemented for use to minimize anesthesia time as a life saving measure in the severely injured. This study is a retrospective review of a 30-month period in which 68 patients with 91 fractures underwent Ender intramedullary nailing. The mean Injury Severity Score (ISS) was 12.4. There were 16 humerus fractures, 26 femur fractures, and 49 tibia fractures. Thirty-three per cent (30 fractures) were open fractures. The average operating time per fracture was 70 minutes (range, 15 to 150 minutes). The estimated blood loss per fracture was 150 cc with a range of 25 to 500 cc. The average followup is currently 19 months (range was 8 to 29 months). This approach achieved an excellent result in 95% of the patients treated. There were no wound, soft-tissue, or bony infections experienced. Major complications were seen in five patients: three nonunions and two malunions.(ABSTRACT TRUNCATED AT 250 WORDS)