Biomedical subjects

Marco Caversaccio

Publications and source records attributed to Marco Caversaccio.

23 records · Page 2Linked to original sources

PubMed2003

On the development and comparative evaluation of an ultrasound B-mode probe calibration method.

OBJECTIVE: Precise transducer calibration is an essential prerequisite for reliable surface registration based on ultrasound B-mode imaging devices. The clinical usage of a novel B-mode transducer calibration technique was evaluated and its attainable calibration precision assessed. MATERIALS AND METHODS: The Three Wire Method and the Cambridge Calibration Method were used as reference techniques to compare the efficiency, calibration precision and spatial requirements of the different techniques. A total of 20 calibration trials were performed using each technique and were statistically evaluated for accuracy and speed. RESULTS: The mean error characterizing the calibration precision of the Three Wire Method was 3.2 mm, obtained in a phantom with a volume of 14 x 10(6) mm(3) in 18.48 min. The Cambridge method resulted in a mean calibration error of 2.2 mm, but required a larger phantom with a volume of 35 x 10(6) mm3 to be used for a duration of 9.30 min. The proposed method yielded an average calibration error of 1.9 mm and was performed, on average, in 2 min using a phantom with a size smaller than 1 x 10(6) mm3. CONCLUSIONS: The suggested calibration method offers decreased time and space while retaining an equivalent calibration precision when compared to established reference methods.

Calibration↗

PubMed2003

Hemostasis in endoscopic sinus surgery using a specific gelatin-thrombin based agent (FloSeal).

The safety and efficacy of a new hemostatic sealant, based on a gel with collagen derived particles and topical thrombin (FloSeal, Fusion Medical Technologies, Inc. Fremont, CA) were assessed as an alternative to nasal packing for hemostasis in functional endoscopic sinus surgery. In a prospective clinical study of 50 patients undergoing bilateral endoscopic anterior ethmoidectomy, 2 ml FloSeal was used after surgery to stop bleeding. The results were compared to a control group of 50 patients with Merocel packing and showed that intraoperative hemostasis was rapid and equal in both groups. The main advantages of the new hemostatic sealant included a higher degree of comfort during postoperative nasal breathing and absence of complaints due to pressure or pain. There was only one case of postoperative bleeding on the 6th day, which required nasal packing. There were no more cases of stenoses or synechia in the ostiomeatal complex than were found in the Merocel group. No systemic side effects due to FloSeal were observed. This specific hemostatic sealant was shown to be a safe and efficacious alternative method for hemostasis in endoscopic sinus surgery with high patient satisfaction and an easy and fast mode of application.

Blood Loss, Surgical↗

PubMed2002

Esthesioneuroblastoma: irradiation alone and surgery alone are not enough.

PURPOSE: To evaluate the long-term outcome of patients with esthesioneuroblastoma treated with neoadjuvant or definitive radiotherapy (RT). METHODS AND MATERIALS: Between 1980 and 2001, 28 patients with histologically confirmed esthesioneuroblastoma underwent RT, with a median dose of 60 Gy (range 38-73). The median age was 58 years (range 16-85). According to the Kadish classification, 4 patients had Stage A, 8 Stage B, and 16 Stage C tumors. Radical resection was performed in 13 cases, in 9 before RT and in 4 after RT because of stable or progressive disease. The outcome analyses included the median age (58 years), Kadish stage, skull base penetration, intraorbital extension, resection status, and total dose ( 60 Gy). RESULTS: After a mean follow-up of 68 months, 54% of patients were free of tumor progression. The 5- and 10-year local progression-free survival rate was 81% and 51%, respectively, and the disease-free survival rate was 70% and 25%, respectively. Four of ten deaths (4/10) were intercurrent, resulting in a cause-specific survival of 77% and 69% at 5 and 10 years, respectively. Radical resection offered significantly better local progression-free survival and disease-free survival (p <0.02). Skull base penetration (p <0.04), intraorbital extension (p <0.04), and Kadish C stage (p <0.06) were important for impaired disease-free survival. CONCLUSION: Despite doses up to 73 Gy, radical RT cannot replace radical resection, which classifies esthesioneuroblastoma as rather radioresistant. Because of its biology and the high rates of late recurrence, we recommend a radical strategy with resection, high-dose RT, and simultaneous chemotherapy. We are aware that some tumors qualify for palliative treatment only.

Adolescent↗

PubMed2002

Present state and future perspectives of computer aided surgery in the field of ENT and skull base.

BACKGROUND: CAS technology has emerged in the last 10 years and is more and more used for surgery of the anterior and lateral skull base. Endoscopic and microscopic CAS systems are available. The endoscopic key hole or minimal invasive procedure is used increasingly not only for treatment of inflammatory disease, but also for tumour surgery. The integration of CAS systems into these procedures raises the level of their safety and efficiency. In addition, they allow the distance to the bone border on the CT slices to be previewed and measured. OBJECTIVE: Review of the present state of CAS systems, our own experience as a research centre and as users of the systems, demonstration of new navigational devices, microscope integration and a new registration procedure developed for the "Bernese" frameless optical navigation system (SurgiGATE ORL@1000, medivision, [Synthes, Stratec-medical], CH-4436 Oberdorf). MATERIAL AND METHODS: The optical CAS system with microscope integration (VM 900@1000, Möller-Wedel, Germany), new devices and new matching procedure; accuracy tests on a cadaver skull and on the patient's head. RESULTS: The practical accuracy on the cadaver skull with the pointer system has a mean average error of 0.79 mm, and the clinical accuracy is between 0.5 mm and 2 mm. CONCLUSION: CAS-microscope integration, new CAS technical devices and new noninvasive CAS-registration procedures support the surgeon in more minimally invasive surgical procedures of the paranasal sinuses and the skull base. Future perspectives will be discussed.

Humans↗

PubMedDate not supplied

Virtual simulator as a training tool for endonasal surgery.

BACKGROUND: Virtual simulation could be an important tool for medical and surgical training as well as education. The efficacy of a simulator for endoscopic nasal procedures in a training program was evaluated. METHODS: The simulator is a medical and scientific tool for visualizing and interacting with three-dimensional volumetric data. Twenty endonasal operations with chronic rhinosinusitis were simulated by two 3rd-year residents and proctored by the senior surgeon 1 day before the actual surgery was performed with an endoscope and computer-aided surgery. A questionnaire was established. RESULTS: The surgical simulator may provide a better understanding of the morphology of the paranasal sinuses with a minor impact on performance of endoscopy by junior residents. Disadvantages identified were time consumption, absence of force feedback, and subtle handling of the joysticks. CONCLUSION: The virtual simulator allows the nonendoscopically nasal trained surgeon to understand and practice endonasal surgery using real-patient data but failed to make an impact on operating room performance. Furthermore, the simulator's effectiveness was limited by the absence of force feedback, subtle handling of the joysticks, and considerable time consumption.

Clinical Competence↗