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Biomedical subjects

A Arezzo

Publications and source records attributed to A Arezzo.

At least 19 recordsLinked to original sources
PubMed2000

Experimental trial on solo surgery for minimally invasive therapy: comparison of different systems in a phantom model.

BACKGROUND: Robotic aid in minimally invasive surgery (MIS) is becoming more and more common. We designed an experimental trial in a phantom model to verify the feasibility of solo surgery for MIS. By performing laparoscopic cholecystectomy on a phantom model, we compared combinations of different systems available in terms of safety, comfort, and time requirements. METHODS: Two surgeons skilled in endoscopic procedures tested the following systems as endoscope holders: the robotic system (AESOP), foot-controlled (AESOP 1000), and voice-controlled (AESOP 2000); the remote controlled FIPS Endoarm, electrically driven and controlled by a finger-ring joystic; the passive system TISKA Endoarm, a mechanical arm moved by hand and fixed by electromagnetical brakes. All of these systems combined with a second TISKA Endoarm as an instrument holder. A combination of two mechanical Martin arms, c, also was tested. The results were compared with those from a control group involving an assistant surgeon. A total of 70 experiments were performed. RESULTS: The shortest dissection time was registered by the combination of two TISKA Endoarms, with a statistically significant difference as compared with the control group (p < 0.05) and experiments using AESOP 1000 (p < 0.05). The TISKA Endoarm also proved to be more comfortable when used as an instrument holder (p < 0.001 vs Martin arm), and rated second only to AESOP 2000 as an endoscope holder. The rating of AESOP 2000 as endoscope holder was significantly higher than that of all other groups (p < 0.001). The study proved the feasibility of solo surgery. The time needed for dissection was shortest when two TISKA Endoarms were used, demonstrating the possible advantages of solo surgery. The TISKA Endoarm received a subjective positive rating when used as both endoscope holder and instrument holder. The voice control of AESOP 2000 seemed to be a major improvement in the development of an optimal man-machine interface. Nevertheless, the system presents considerable space requirements and does not supply control of 30 degrees optics. The principle of the finger-ring joystick adopted by the FIPS Endoarm seemed very intuitive but lacking in ergonomy. CONCLUSION: Laparoscopic solo surgery can be considered a safe procedure, although further technologic developments should lead to improved ergonomy, intuitiveness of handling, and architecture of the systems, offering the surgeon better control, increased precision of action, and reduction in operation time.

Minimally Invasive Surgical Procedures↗
PubMed2000

A new remote-controlled endoscope positioning system for endoscopic solo surgery. The FIPS endoarm.

In the field of endoscopic solo surgery, the assistance received by the surgeon from ergonomical positioning devices is extremely important. They aid in both the retracting of instruments and the positioning of the endoscope. However, passive systems derived from open surgery have not proved satisfactory. Therefore, we set out to develop a remote-controlled arm capable of moving a rigid endoscope with about four degrees of freedom, while maintaining an invariant point of constraint motion coincident with the trocar puncture site through the abdominal wall. The system is driven by means of speaker-independent voice control or a finger-ring joystick clipped onto the instrument shaft close to the handle. When the joystick is used, the motion of the endoscope is controlled by the fingertip of the operating surgeon, which is inserted into the small ring of the controller in such a way as to make the motion of the fingertip correspond directly to the motion of the tip of the endoscope. A study was performed to compare the two different interfaces available for the system. With both interfaces, the guiding system allows for transparent and intuitive operation. Its set-up is easy; it is safe and reliable to use during the intervention; and it is faster than human assistance. With its improved ergonomy, this new generation of remote-controlled endoscope positioning system represents a further step toward the diffusion of solo surgery techniques in minimally invasive therapy. In our opinion, this prototype creates a valid compromise between human and robotic control of rigid endoscopes.

Animals↗
PubMed2000

Prospective randomized trial comparing bowel cleaning preparations for colonoscopy.

Colonoscopy is commonly accepted as the procedure of choice for the detection and treatment of colonic lesions. The current study was undertaken to compare effectiveness and tolerance of different bowel preparations. Three hundred patients were randomized into three groups, to be administered either a senna compound, a polyethylene glycol lavage, or an oral sodium phosphate (NaP) solution. Tolerance of the preparation was considered. After each colonoscopy, the endoscopist blindly scored cleansing for each bowel segment and defined the quality of the examination as "optimal," "acceptable," or to be repeated. Significantly more patients in Group C (68%) achieved a "good" cleansing compared with Group B (50%; P < 0.0001) and with Group A (38%; P < 0.005). Sixty-three percent of constipated patients obtained a "good" preparation in Group C, which was significantly higher than in Group A (28%; P < 0.05) and than in Group B (42%; P < 0.02). Feasibility of the examination was considered "optimal" in 80% of procedures in Group C, which was higher than in Group A (59%; P < 0.005) and in Group B (62%; P < 0.005). The tolerance of preparation was "good" in 93% of the examinations for Group C. This prospective randomized trial showed good effectiveness of NaP solutions, with an optimal tolerance. Results of use of the NaP solution showed a clear advantage for constipated patients, with similar results for nonconstipated patients. The author believes that the NaP solution should be the standard preparation for elective colonoscopy.

Aged↗
PubMed2000

[Positioning systems for endoscopic solo surgery].

BACKGROUND: Endoscopic surgery has acquired undisputed importance in the field of both general and specialised surgery. The introduction of robotic technology in surgery has recently led to the development of new positioning systems for endoscopic surgery. These allow direct control of the endoscopic procedures by the surgeon, whose vision currently depends on the assistant in charge of positioning the optic camera in compliance with his wishes. METHODS: We experimented different positioning systems for optics and rigid endoscopic instruments for laparoscopy, some of which were our own design. Over 400 cholecystectomies were carried out by six different surgeons on phantoms containing animal organs. The experimental systems were AESOP (Computer Motion, USA), with both foot-pedal and voice control, ENDOASSIST (Armstrong Healthcare Co. UK), controlled by a device worn by the surgeon, FIPS Endoarm (Karlsruhe Research Centre, Germany), controlled by a joystick and voice, and the passive TISKA Endoarm system (Karlsruhe Research Centre, Germany). Combinations of two systems were compared, using one to position the optic and one to position the retractor instrument. RESULTS: Phantom tests, which are preferable owing to constant conditions, showed the feasibility of experiments in Solo Surgery conditions and highlighted the advantages and drawbacks of the various systems. In particular, the surgeons appreciated the intuitive use of the TISKA Endoarm system as a positioner for the retractor instrument and the optics, in spite of the fact that it was only a passive movement apparatus. Among the remote-control systems tested as an optics positioner, FIPS Endoarm controlled by a joystick was particularly intuitive and produced the best results in terms of time taken to complete the procedure. The time taken was even shorter than that in a large control group with human assistance. CONCLUSIONS: In our experience endoscopic Solo Surgery was found to be applicable to clinical practice. This will bring numerous advantages in terms of the precision of surgical procedures and savings in terms of time and human resources, with a consequent reduction of management costs. There is no doubt that this method represents a step forward in the application of technology to surgery.

Endoscopes↗
PubMed1999

Trocar and instrument positioning system TISKA. An assist device for endoscopic solo surgery.

The assistance received by the surgeon from support personnel during surgical laparoscopy is extremely important. This includes the retracting of instruments and the positioning of the endoscope. However, human assistance is costly and often does not provide satisfaction for the surgeon. The aim of the project was to develop a mechanical arm capable of manipulating a laparoscopic instrument under the control of the operating surgeon. The system design is based on a particular kinematic construction that maintains an invariant point of constraint motion coincident with the trocar puncture site through the abdominal wall. The guidance system allows transparent and intuitive operation, and its setup is easy and quick. It may be adapted either as an instrument retractor or as an optic positioning device. A new generation of instrument positioning systems, with improved ergonomy, will be a first step toward the diffusion of solo surgery techniques in minimally invasive therapy. We believe this prototype represents a valid compromise between human and robotic control for conventional laparoscopic instruments.

Animals↗
PubMed1999

The role and future of endoscopic imaging systems.

Visual perception is the main sensory input from the environment in most situations of daily life. It is the only sensory input from the operating field in endoscopic surgery, and thus the qualities of the optical imaging system have a considerable impact on the course of the surgical intervention. Significant improvements have been made recently in various fields of science and engineering, influencing endoscopic imaging systems in experimental and clinical use. Among these are technologies that improve the endoscope itself in terms of providing new visual features, such as fogging prevention and plastic images, using new illumination techniques. Other developments concern the improvement of image resolution and color fidelity through new charge-coupled device (CCD) sensors or alternative techniques for image creation. Finally, the combination of endoscopic technologies with robotics provides for intuitive and more efficient direction of the line of sight.

Endoscopes↗
PubMed1999

Robotics and systems technology for advanced endoscopic procedures: experiences in general surgery.

The advent of endoscopic techniques changed surgery in many regards. This paper intends to describe an overview about technologies to facilitate endoscopic surgery. The systems described have been developed for the use in general surgery, but an easy application also in the field of cardiac surgery seems realistic. The introduction of system technology and robotic technology enables today to design a highly ergonomic solo-surgery platform. To relief the surgeon from fatigue we developed a new chair dedicated to the functional needs of endoscopic surgery. The foot pedals for high frequency, suction and irrigation are integrated into the basis of the chair. The chair is driven by electric motors controlled with an additional foot pedal joystick to achieve the desired position in the OR. A major enhancement for endoscopic technology is the introduction of robotic technology to design assisting devices for solo-surgery and manipulators for microsurgical instrumentation. A further step in the employment of robotic technology is the design of 'master-slave manipulators' to provide the surgeon with additional degrees of freedom of instrumentation. In 1996 a first prototype of an endoscopic manipulator system. named ARTEMIS, could be used in experimental applications. The system consists of a user station (master) and an instrument station (slave). The surgeon sits at a console which integrates endoscopic monitors, communication facilities and two master devices to control the two slave arms which are mounted to the operating table. Clinical use of the system, however, will require further development in the area of slave mechanics and the control system. Finally the implementation of telecommunication technology in combination with robotic instruments will open new frontiers, such as teleconsulting, teleassistance and telemanipulation.

Equipment Design↗
PubMed1998

Is euthyroidism the goal of surgical treatment of diffuse toxic goitre?

OBJECTIVE: To find out by studying a homogeneous group of patients whether euthyroidism is achievable by surgical treatment of diffuse toxic goitre. DESIGN: Retrospective study. SETTING: Teaching hospital, Italy. SUBJECTS: 128 of the 152 patients operated on for diffuse toxic goitre during the period January 1971-December 1994 and followed up for a median of 83 months (range 6-289). INTERVENTION. Standard subtotal thyroidectomy. MAIN OUTCOME MEASURES: Operative mortality, recurrence, hypothyroidism and late complications. RESULTS: There were no operative deaths. After 10 years follow up, 11 patients (9%) had developed recurrences and 61 (48%) were euthyroid. In the univariate analysis the risk of hypothyroidism was significantly associated with the year of operation (p = 0.04), the duration of symptoms (p < 0.01), and the degree of lymphocytic infiltration (p < 0.01). The last two were confirmed by multivariate analysis. CONCLUSION: Subtotal thyroidectomy seems to be an effective treatment of diffuse toxic goitre as a stable euthyroid state can be achieved in nearly half the patients after a prolonged follow up.

Adolescent↗
PubMed1998

Toxic thyroid adenoma: absence of DNA mutations of the TSH receptor and Gs alpha.

DNA point mutations of the TSH receptor and of the alpha subunit of the stimulatory GTP-binding protein (Gs alpha) have been suggested as major causes of hyperfunctioning thyroid adenomas. However, significant differences in the prevalence of these mutations (from 0.3 to 84%) have been found in different populations. The present study was designed to evaluate further the presence of mutations in discrete fragments of cDNA encoding critical regions of the TSH receptor and of the Gs alpha involved in signal transduction and cAMP production. Genomic DNA extracted from 15 thyroid adenomas and surrounding quiescent thyroid tissues was used as a template to amplify four DNA fragments of TSH receptor and one DNA fragment of Gs alpha. TSH receptor and Gs alpha DNAs were analyzed by a number of techniques. We did not detect any mutations (new or previously described) in our patients. These results confirm that the causes of solitary toxic adenomas are protean, and only some of them may be somatic DNA point mutations. Since the clinical features of solitary toxic adenoma are homogeneous, it could be important to establish the specific molecular defect underlying each case, in order to follow up the patients and to assess their clinical evolution.

Adenoma↗
PubMed1998

Mucoepidermoid carcinoma of the thyroid gland arising from a papillary epithelial neoplasm.

We report a case of mucoepidermoid carcinoma of the thyroid gland. The simultaneous association of papillary and mucoepidermoid carcinoma in a Hashimoto's thyroiditis makes the present observation unusual. Surgery was limited due to local extension of the neoplasm. The patient consequently underwent external radiotherapy followed by radiometabolic therapy. The patient survived 11 months after diagnosis. As far as the histogenesis of the neoplasm is concerned, we believe that mucoepidermoid areas correspond to squamous and mucinous metaplasia of a preexisting papillary carcinoma. Transition areas between elements morphologically characteristic of both neoplasms were observed. Histochemical and immunohistochemical studies confirmed the diagnosis of a carcinoma with multiple aspects showing a focal positive reaction for thyroglobulin or keratin antisera. Therefore, this demonstrates different functional activities of the neoplastic cells. There is still debate about adjuvant therapies, the results of which appear for the moment very poor.

Aged↗
PubMed1998

[The role of drainage and antibiotic prophylaxis in thyroid surgery].

BACKGROUND: It is our habit to employ an open drainage after thyroid surgery in our department. We have also found a large number of surgical infections in these patients (5.8% vs 2.5). Aim of the study is to evaluate prospectively if contamination happens during surgical procedure or in a later time according to the presence of the open drainage. METHODS: From October 1995 to November 1996, 113 patients who underwent a subtotal thyroidectomy were randomized into two groups: group A with antibiotic prophylaxis (57 patients) and group B without it (56 patients). RESULTS: One case (1.7%) of sepsis among 57 patients of group A and 2 cases (3.4%) among 56 patients of group B were observed. CONCLUSIONS: No statistical difference was found between the two groups despite antibiotic prophylaxis covering surgical procedure. It is personal opinion that sepsis arose after surgical procedure, due to the presence of the open drainage.

Adult↗
PubMed1997

Surveillance after colorectal cancer surgery.

Early diagnosis of local and distant recurrences of colorectal cancer remains difficult and there is no agreement on the effectiveness of follow-up in these patients. The aim of this study is to assess the value of our method of follow-up. We consider 239 patients with colorectal cancer and at least 2 years follow-up following radical resection. A local recurrence appeared in 26 patients (10.9%), a distant metastasis in 41 (17.1%), while in seven (2.9%) local and distant recurrences appeared simultaneously. Local recurrence was detected because of an increase in carcinoembryonic antigen (CEA) level in 15 patients (57.7%), during a scheduled endoscopy in four (15.4%) and because of symptoms in seven (26.9%). In seven patients (26.9%) a radical resection was possible. Distant metastases were detected by CEA levels in 20 patients (48.8%), by ultrasonography (U.S.) in 12 (29.3%) and by chest X-ray in five (12.2%). In 13 of 26 patients with liver metastases a resection was performed. This study shows that few patients benefit from follow-up and only CEA levels and liver U.S. performed intensively between 15 and 36 months after surgery are useful in early detection of recurrences. A modification of the follow-up to the single patient, according to the stage, location and grading of cancer, could improve the results, so lowering the costs of this expensive practice.

Barium Sulfate↗
PubMed1996

Differentiated thyroid cancer: surgical treatments of 190 patients.

Between 1968 and 1991, 190 patients (51 men, 139 women) with a mean age of 46.3 years underwent surgery for differentiated thyroid cancer (148 papillary and 42 follicular carcinomas). In 29.5% of the cases a concomitant goitre was histologically demonstrated. These patients were significantly older (mean: 54.7 years) (P<0.01). The patients who had previously received cervical radiotherapy were significantly younger (mean: 29.7 years) (P<0.01). The analysis of historical and clinical findings failed to identify predictive factors of biological aggressiveness. Hyperthyroidism occurred in 5.7% of patients: this subgroup did not show any difference in clinical behaviour. Occult carcinoma (14.7%) and multifocality (9.4%) were found more frequently in the glands with a pre-existent goitre (P<0.05), but the clinical significance of these aspects is uncertain. The surgical treatment of choice was total thyroidectomy (135 patients); more conservative procedures were performed only in younger patients with small lesions, without a difference in survival. Post-operatively a permanent recurrent laryngeal nerve injury occurred in four patients (2.1%) and nine patients (4.7%) required a permanent calcium supplementation. Among patients in follow-up (91.6%), those who underwent a total thyroidectomy were studied using a total body scinti scan. A poor prognosis was associated with age (>40 years), pT, stage, pM and symptomatic metastases.

Adenocarcinoma, Follicular↗
PubMed1995

Surgical management of substernal goiter: analysis of 237 patients.

Between 1968 and 1991, 237 patients underwent thyroidectomy for substernal goiter. Sixteen of them presented malignancies (6.8%). Mean age of the 159 women and 78 men was 57.7 years. Twenty-five patients had undergone previous thyroid surgery. The initial symptoms were cervical mass (72%), compression (16.2%), hyperthyroidism (13.1%), hypothyroidism (1.3%), and 5.5 per cent were asymptomatic. Most patients had long-standing goiter (mean duration: 12.9 yrs). All but eight operations were performed through a cervical incision. There were two postoperative deaths (0.8%), both in patients with advanced neoplasms. Early postoperative complications were hemorrhage (0.8%), dysphonia (4.6%), and transient hypocalcemia (2.9%). Five patients (2.1%) required tracheotomy. Complications were more frequent after total thyroidectomy than partial resection (P < 0.05), after surgery for malignancy than for benign disease (P < 0.05), and in complex than in simple forms (P < 0.05). One hundred ninety-four patients were followed after surgery; dyspnea was found in two patients (1.0%), dysphonia in seven (3.6%), and hypoparathyroidism in one. Analysis of our data indicates that 1) substernal goiter arose in elderly patients more than a decade later than cervical goiter; 2) goiters with a "complex" endothoracic development had an increased rate of short and long term complications; 3) cancer occurred in a significant number of patients, without any specific symptoms of malignancy; 4) the group of patients with hyperthyroidism was characterized by a significantly longer clinical history than euthyroid patients; 5) nearly all substernal goiters could be approached through a cervical collar incision; 6) the morbidity and mortality were low also after sternotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Shadow optic. An endoscope with optimized ligth].

Modern endoscopes use a single mid-frontal illumination source that yields an unnatural flat image. At the University of Tübingen, in collaboration with Gimmi GmbH (Tuttlingen, Germany), a new concept endoscope has been developed with an additional light source: the shadow optic. With the aid of a secondary light source along the axis of the endoscope, a shadow is obtained which gives an impression of spatial depth. The aim of the study was to assess this new endoscope objectively, focusing on the speed and safety of the surgical act. The shadow optic was used in an experimental setting by 20 probands, each of whom performed five different standardized procedures of increasing difficulty five times, with and without shadow optic in randomized sequence, making a total of 1000 experiments. The procedures consisted in spatial orientation tests, structure-surrounding maneuvers, tissue clamping, needle puncture and suturing. The evaluation criteria were the time required to perform the procedures and the number of predefined errors as determined by electronic control. In each procedure, the time needed to perform the experiments was shorter with the shadow optic, reductions of up to 18% being recorded, and the number of errors was up to 54% lower compared to the experiments conducted with the traditional endoscope. The results of the study demonstrate that, as a result of the more natural spatial view conditions, the procedures were performed faster and with greater precision when the shadow optic was used. The endoscopic imaging with the shadow optic makes for better spatial orientation and a more natural and manageable image.

Endoscopes↗
PubMedDate not supplied

[Robotic and systems technology for advanced endoscopic procedures].

The advent of endoscopic techniques changed surgery in many regards. This paper intends to describe an overview about technologies to facilitate endoscopic surgery. The systems described have been developed for the use in general surgery, but an easy application also in other fields of endoscopic surgery seems realistic. The introduction of system technology and robotic technology enables today to design a highly ergonomic solo-surgery platform. This consists of a system of devices for endoscopic surgery (HF, light source, etc...) with which the surgeon interacts directly, positioning systems for optic and instruments that the surgeon drives as the likes without assistance, and a chair to increase the comfort of the surgeon during surgery. The system of endoscopic devices named OREST (Dornier, München) designed already in 1992 opened the way to a number of systems available today that allow to the surgeon a direct control of the instrumentation. A considerable step ahead in endoscopic technology is the introduction of robotic technology to design assisting systems for solo-surgery and microsurgical instrument manipulators. Results of a number of experimental trials on combinations of different positioning devices are presented and commented. A further step in the employment of robotic technology is the design of "master-slave manipulators" to provide the surgeon with additional degrees of freedom of instrumentation. In 1996 a first prototype of an endoscopic manipulator system, named ARTEMIS, designed in cooperation with the Research Center in Karlsruhe, could be used in experimental applications. Clinical use of the system, however, will require further development of the arm mechanics and the control system. The combination with the implementation of telecommunication technology will open new frontiers, such as teleconsulting, teleassistance and telemanipulation.

Endoscopes↗