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Biomedical subjects

M Caversaccio

Publications and source records attributed to M Caversaccio.

At least 19 recordsLinked to original sources
PubMed2001

Frameless optical computer-aided tracking of a microscope for otorhinology and skull base surgery.

OBJECTIVES: To integrate a digitally controlled operating microscope without a laser autofocus system into a frameless optical computer-aided surgery system and to test the accuracy and usability of this system in otorhinological surgery. DESIGN: Experimental study and case series. SETTING: Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Inselspital, and the Maurice E. Müller Institute for Biomechanics, University of Bern, Bern, Switzerland. PATIENTS: Eight computer-aided microscopic surgical procedures were performed between January and October 2000 on patients with various diseases of the anterior and lateral skull base. RESULTS: The practical accuracy of the navigated microscope on the lateral side of a cadaver skull was 2.27 +/- 0.25 mm and on the anterior side of the same skull was 2.07 +/- 0.35 mm. In all 8 cases of computer-aided microscopic surgery, no complications occurred. Clinical inaccuracy was 2 to 3 mm. CONCLUSION: Integration of a low-cost, non-laser autofocus microscope into our computer-aided surgery system was successfully performed and offers surgeons the ability to combine the precise optics of the operating microscope with the localization power of a computer-aided system.

Cadaver↗
PubMed2001

Endonasal and transcanalicular Er:YAG laser dacryocystorhinostomy.

In the last 10 years different types of lasers were used for dacryocystorhinostomy (DCR). Between April 1998 and August 1999, a fibreoptic erbium laser DCR was performed on 12 patients. Eight cases were for a presaccal stenosis and 4 cases for a postsaccal stenosis. An erbium laser with a specially designed handpiece was used endonasaly and transcanaliculary. Preoperative epiphora was present in all patients. Double bicanalicular nasal silicone tubes were placed during surgery in all cases. The 3 cases of postoperative failure included 2 cases of presaccal stenosis and 1 case of the postsaccal group; failure manifested with recurrent epiphora/dacryocystitis; the onset of symptom recurrence varied from 9 weeks to 11 weeks postoperatively. Laser-assisted DCR includes the avoidance of a cutaneous incision, excessive tissue injury, the advantage of short operation time and precision. Suitable indications for the erbium laser are stenoses in the canaliculi, in the sac, but also for bone lacrimal bone cutting.

Adult↗
PubMed2000

Endovascular treatment of acute and subacute hemorrhage in the head and neck.

OBJECTIVE: Acute and subacute hemorrhage in the head and neck often represent a life-threatening situation. The goal of this study is to evaluate the indications for and contributions of endovascular techniques in the diagnosis and management of such severe cases. DESIGN: Seventy-two patients with acute or subacute intractable hemorrhage of the head and neck were treated over a period of 5 years: 2 patients had experienced trauma; in 6 cases the cause of bleeding was iatrogenic; and in 2 patients intraosseous arteriovenous malformations were manifested. Fifteen patients had tumors, 9 of whom had prior radiotherapy. Forty-seven patients presented with epistaxis (41 idiopathic and 6 during anticoagulation therapy). The endovascular therapy was performed using polyvinyl alcohol particles, fibered platinum or electrolytically detachable coils (Guglielmi detachable coils; Target Therapeutics, Fremont, Calif), a stent, glue (Ethibloc; Ethicon GmbH, Norderstedt, Germany, and Histoacryl; B. Braun Melsungen AG, Melsungen, Germany), or with a combination of these different embolic materials. RESULTS: The acute bleeding was successfully controlled in all cases. Fourteen patients (7 with epistaxis, 5 with tumors, and 2 with arteriovenous malformations) had to be embolized more than once before the bleeding could be controlled. The idiopathic, traumatic, iatrogenic, and remaining tumoral cases were treated only once. The long-term morbidity was 1.9%. CONCLUSIONS: Owing to the recent continuous advances in interventional radiologic techniques, it is possible to treat both acute and subacute life-threatening head and neck hemorrhage most efficiently. In many cases the endovascular therapy complements surgery.

Acute Disease↗
PubMed2000

Frameless computer-aided surgery system for revision endoscopic sinus surgery.

To increase the intraoperative safety factor and to acquire anatomic assistance during revision endoscopic sinus surgery (RESS), we used an optical computer-aided surgery (CAS) system that we developed collaboratively in Bern, Switzerland. During 1 year, 25 RESSs were performed with CAS: recurrent polyposis (n = 20), recurrent frontal recess stenosis (n = 3), and recurrent frontal recess stenosis with mucocele (n = 2). These patients were compared with a control group of 10 patients undergoing RESS without CAS. The same surgeon (M.C.) performed all operations, and there were no minor or major complications in either group. The clinical inaccuracy of our system is between 0.5 and 2 mm with paired-point and surface matching. The navigation system is an important aid to surgeons in identifying anatomic landmarks that are typically difficult to visualize in this type of surgery, thus reducing the stress placed on the surgeon.

Endoscopy↗
PubMed2000

Unilateral choanal atresia. A possible indication for computer aided surgery? "A report of two cases".

Choanal atresia (CA) is a congenital obstruction of the posterior nose. Bilateral CA is a paediatric emergency and must be treated surgically in the first few weeks after birth. This is in contrast to unilateral CA, because surgical management can be planned more selectively. Transpalatinal surgery for CA is a safe procedure. The endonasal technique is minimally invasive and less traumatic; however, a major disadvantage is a limited field of vision. Computer aided surgery using images acquired by computer tomography (CT) or magnetic resonance imaging (MRI) is an application that has emerged in the last few years. This application provides an additional safety factor for endoscopic surgery to resolve choanal atresia, especially in cases of another malformation. We report results from two cases of unilateral CA who were surgically managed with Computer aided surgery.

Adolescent↗
PubMed2000

Practical aspects for optimal registration (matching) on the lateral skull base with an optical frameless computer-aided pointer system.

HYPOTHESIS: Paired-point matching and surface matching are highly accurate when used on the lateral skull base with an optical computer-aided surgery system. BACKGROUND: Computer-aided surgery on the lateral skull base can be done with a pointer system or with the microscope. An optical pointer system that uses anatomic landmarks and surface points has been developed in Bern, Switzerland. METHODS: Axial computed tomography of a cadaver skull was performed. The images were processed on a computer workstation. An infrared camera was used. A reference base mounted on the head and a needle pointer, both equipped with light-emitting diodes, were used. Different anatomic landmarks were determined on the computer image of the skull and were compared with the actual anatomic markers taken on the bone or on the skin simulation material, and the target error was defined. In a second step, additional surface points on different regions of the skull were taken, and the inaccuracy from the target was redetermined. RESULTS: The authors found a mean average error in accuracy from the target with paired-point matching alone in the best series of 0.79 mm. Under skin simulation, they found a deterioration with paired-point matching alone but an improvement in accuracy with surface matching. CONCLUSION: For this navigation system, it is recommended that the following five anatomic points be selected for matching of the lateral skull base: the tip of the mastoid, the mastoid foramen, the umbo, the frontozygomatic suture, and the anterior nasal spine. For additional accuracy in clinical situations, surface matching is recommended.

Microscopy↗
PubMed2000

[Diagnosis and treatment of temporal paragangliomas: an analysis of 21 cases treated in Bern between 1992 and 1999].

INTRODUCTION: Paragangliomas are usually benign tumours stemming from the neural crest which may have neuroendocrine activity. Because of hypervascularisation they usually lead to pulsatile tinnitus. Local expansion initially causes middle ear and later inner ear hearing loss, and cranial nerve dysfunction. PATIENTS/METHODS: Signs and symptoms, demographic data, tumour stages, treatments and outcomes were analysed for the 21 patients treated at our clinic between 1992 and 1999. Among 16 surgically treated patients 3 type A and 4 type B tumours were treated by mastoidectomy and middle ear reconstruction. For the 8 type C and one type D tumours, angiography was performed preoperatively, usually followed by selective embolisation of tumour vessels, in 7 cases with additional permanent occlusion of the internal carotid artery. These 9 tumours were removed through an infratemporal approach with partial petrosectomy, preservation of the inner ear and facial nerve rerouting, followed in 8 cases by middle ear occlusion. The patient with a type D2 tumour had a two-stage otological and neurosurgical operation. One patient with type C3 tumour only underwent radiation therapy. 4 patients have had no treatment so far: 2 had small type A tumours and one a type C3 tumour but contraindications for surgery. A last patient with a slowly growing type D2 tumour cannot be operated on due to general health problems. RESULTS: All patients with type A and B tumours had normal to subnormal postoperative hearing and normal facial nerve function. In one case with a type C tumour the middle ear reconstruction led to normal hearing thresholds. After rerouting of the facial nerve, transient palsy was noted in 6 out of 9 cases. In 3 patients a slight permanent impairment of facial nerve function (House-Brackman II) remained. 4 patients had some dysfunction of cranial nerves IX-XII postoperatively. After a follow-up of up to 8 years (mean 5 years) no recurrence was observed in the surgically treated patients. The patient treated by radiation had further tumour growth and another treatment is being planned. Among the 4 patients followed without treatment, no tumour growth has been observed up to now in 3 patients. DISCUSSION: Our study confirms that the well standardised conservative surgical treatment allows reliable removal of paragangliomas in most cases, and involves low morbidity.

Cranial Nerve Diseases↗
PubMed2000

[Excision and drainage of cholesterol granulomas of the petrous apex with preservation of hearing under computer-assisted navigation surgery (CANS)].

Diagnosis of cholesterol granuloma of the petrous apex has become easier today with new imaging techniques such as MRI and CT. The therapy of choice is surgery, which is still considered a delicate procedure. The objective is to demonstrate hearing-preserving excision and drainage of cholesterol granulomas of the petrous apex using the Bernese system of computer-assisted navigation surgery. Between 1995 and 1999, 3 patients with severe temporal headache, tinnitus and nonspecific vertigo had surgery for cholesterol granuloma of the petrous apex with drainage and excision in the University ENT Clinic, Berne. In the first patient, a combined transmastoidal and transtemporal approach was adopted with infralabyrinthine and subcochlear partial petrosectomy and extirpation of the granuloma in the petrous apex (surgery time 7 h). In the following 2 patients computer-assisted navigation surgery was used and transmastoidal infralabyrinthine-subcochlear drainage and excision of the granuloma in the petrous apex was performed after antefacial hypotympanal drilling with partial exposure of the internal carotid artery (surgery time 2.5 h). After surgery patients were rapidly releaved of symptoms. Postoperative CT showed the newly aerated cells in the petrous apex with permanent drainage. Hearing was preserved with slight residual conductive loss. The surgical method of choice for hearing-preserving excision and drainage is made through an infralabyrinthine-subcochlear approach. The application of computer-assisted navigation surgery in the lateral skull base allows permanent intraoperative monitoring of the precise position of the microsurgical instruments (accuracy < 1 mm) giving a high security level for minimally invasive function preserving surgery.

Adult↗
PubMed2000

[The role of chemokines in nasal polyps].

Nasal polyposis is an inflammatory condition of the nose and the sinuses characterised by a marked infiltration of eosinophils in addition to lymphocytes, mast cells and macrophages. The selective recruitment of eosinophils to inflammatory sites is mediated by CC chemokines such as Eotaxin and Eotaxin-2. In the present study histology, immunohistochemistry and ELISA were performed. The levels of Eotaxin and Eotaxin-2 and for comparison other chemokines RANTES and IL-8 were measured in nasal polyp tissue and in control nasal tissue. On histological examination 6 polyps showed an oedematous structure, one was glandular and one had a fibromatous pattern, while all showed a marked eosinophil infiltration. Immunohistochemistry of the polyps showed that epithelial cells were strongly positive for Eotaxin and IL-8, whereas endothelial cells stained positive for Eotaxin-2. Significantly higher amounts of Eotaxin, Eotaxin-2 and IL-8 were detected in polyp tissue when compared with control middle turbinates. The increased levels of eosinophil-stimulating chemokines, such as Eotaxin and Eotaxin-2 in nasal polyps suggest that they may be important regulators of eosinophil recruitment in this inflammatory disease.

Chemokine CCL11↗
PubMed1999

[Objective value of adenotonsillectomy in the child. A prospective study of incidence of tonsillitis, snoring, pulse oximetry and polysomnography and general development before and after adenotonsillectomy].

65 children were analysed prospectively before and after adeno-tonsillectomy to determine the incidence of upper airway infections, snoring and nocturnal obstructive symptoms. The weight and height percentiles were also determined before and after adeno-tonsillectomy. The Oxygen Desaturation Index (ODI) was measured in 27 children suspected of having a sleep apnea syndrome. In six of these children polysomnographic studies were carried out. A statistically significant reduction (p < 0,005) of upper airway infections could be seen six to twelve months after adeno-tonsillectomy. In 25 children (38%), we observed a postoperative weight gain and in eight cases (12%) a height gain. The obstructive symptoms, especially snoring and respiratory apneas, disappeared or were significantly reduced in 90% of the cases after adeno-tonsillectomy. All preoperatively pathological ODI and AHI normalised after the operation (p < 0,005).

Adenoidectomy↗
PubMed1999

The "Bernese" frameless optical computer aided surgery system.

OBJECTIVE: We report on two years of clinical experience with a frameless Computer Aided Surgery system developed in Bern, Switzerland. MATERIAL AND METHODS: Our navigation system is based on a preoperative computer-tomography (CT) scan (without markers) and an intraoperative optical tracking of head movements and of the surgical instruments. Using landmark and surface-based registration, the skull can be accurately correlated to the CT images. The three-dimensional positions of the surgical instruments, as well as the endoscopic images, are displayed in real time on a monitor. RESULTS: In the last two years, 109 computer-aided interventions have been successfully performed: 89 on the anterior skull base/paranasal sinuses, 15 on the lateral skull base, and 5 minimally invasive procedures on other locations in the skull. No complications occurred. The practical accuracy on the cadaver skull is between 0.5 mm and 1.2 mm, and the clinical accuracy is between 0. 5 mm and 2 mm. CONCLUSIONS: Our navigation system has proven its accuracy and usability. Surgeons feel very comfortable with the increased safety provided by the unequivocal identification of important anatomical structures.

Cadaver↗
PubMed1999

[Navigation surgery in diseases of the paranasal sinuses].

BACKGROUND: Since the mid-80s, endonasal sinus surgery has gained significant importance in the treatment of chronic inflammatory sinus disease. Many surgeons have recognized the necessity of developing new methods to increase the safety of this type of surgery. One of the advancements in increasing the safety of endonasal sinus surgery was the development of computer-aided surgical navigation (CAS) systems. METHODS: Since 1996, we have tried several different CAS systems for difficult surgical procedures in sinus and anterior skull base surgery, mainly revision surgery for chronic inflammatory sinusitis and endonasal tumors. During this time, we tried one electromagnetic ("Insta Trak") and two optoelectric systems ("Surgigate" and "Vector Vision"). RESULTS: In our experience, all systems can be used in endonasal sinus surgery; accuracy was satisfactory and varied between 0.1 and 0.5 mm. There were differences with respect to the time of preparation of the system for surgery as well as to the possibility to use different instruments. CONCLUSIONS: Computer-assisted surgical navigation systems today have gained a degree of accuracy which makes them not only suitable but almost necessary, at least for difficult surgical procedures at the anterior skull base, i.e. revision surgery in chronic inflammatory sinus disease. On the long run, these systems will become mandatory for these kinds of procedures. On the other hand, CAS systems cannot substitute thorough anatomical and surgical training.

Computer Systems↗
PubMed1999

Facial nerve function after petrosectomy.

OBJECTIVES: Evaluation of facial nerve function after petrosectomy in a patient series with facial nerve denudation-decompression, forward or backward rerouting, and facial nerve suture and grafting. STUDY DESIGN: Fifty-six patients with petrosectomies performed for 24 benign and 9 malignant tumors of the petrous bone, 13 malignant tumors of the parotid gland or of the infratemporal spaces with infiltration of the petrous bone, 8 traumatic facial nerve disruptions, and 2 osteoradionecroses were retrospectively evaluated with respect to facial nerve function. Sixteen cases involved a partial, 25 a subtotal, and 15 an extended subtotal petrosectomy. METHODS: The treatment of the facial nerve included 15 denudation-compressions, 23 denudation-compressions with rerouting, 4 primary sutures, and 14 nerve grafts. The House-Brackmann grading system was used for facial nerve evaluation. RESULTS: Normal or nearly normal facial nerve function was obtained in facial nerve denudation-decompression with and without rerouting (House-Brackmann Grade I or II) except in cases of malignant tumors and osteoradionecrosis, where preoperative impaired function remained. Satisfactory results were obtained with nerve suturing and nerve grafting after petrous bone fracture (Grade III or IV, in one case practically Grade II) except in a case of late repair 3 years after the trauma (Grade V). Variable results were obtained with nerve grafting in cases with tumor infiltration: Satisfactory results (5 of Grade III or IV) were obtained when the tumor was healed and also when postoperative radiotherapy was applied; poor results were obtained in the case of tumor recurrence (6 of Grade V or VI). CONCLUSIONS: Our results show that petrosectomy with denudation-decompression of the facial nerve with or without rerouting usually results in a normal mimic of the face. When the facial nerve is disrupted by trauma or when the nerve is infiltrated by tumor, early reconstruction with nerve suture or grafting mostly leads to a partial and quite acceptable reinnervation of the face.

Adult↗
PubMed1998

[Otogenic meningitis].

We present three patients with otogenic meningitis, whose illness varied in extent and clinical course. Meningitis and otitis media are associated in 19-22% of all meningitis-patients. Streptococcus pneumoniae is the predominant microorganism with hemophilus influenzae being the second most important. We discuss the importance and problems of spinal puncture, early CT-scan as well as further, more extensive and sophisticated examinations to exclude late complications or predisposing factors. We emphasize an early start of antibiotic treatment, which should not be delayed for diagnostic reasons. With the appearance of highly penicillin-resistant pneumococci antibiotic therapy may become more difficult in the future, but for the moment pneumococcal infections in Switzerland can initially still be treated with cephalosporins or high dose penicillin. The use of steroids, although of unproven efficacy, may be considered in some cases. An otolaryngologist should initially be consulted for diagnostic reasons as well as for possibly indicated early surgery.

Adult↗
PubMed1998

Microsurgical endonasal dacryocystorhinostomy with long-term insertion of bicanalicular silicone tubes.

OBJECTIVE: To assess the results of microsurgical endonasal dacryocystorhinostomy with long-term insertion of single or double bicanalicular silicone tubes in canalicular (presaccal) and ductal (postsaccal) stenosis of the nasolacrimal duct system. DESIGN: Retrospective follow-up of case series between 1992 and 1996. PATIENTS: Thirty-eight patients were included in the study: 19 with ductal stenosis; 28 with canalicular stenosis; and 1 (a 6-month-old girl) with congenital agenesis of the lacrimal duct system. INTERVENTION: Forty-seven endonasal microscopic dacryocystorhinostomies were performed on 38 patients. Bicanalicular silicone tubes were inserted, fixed in the nasal cavity, and left in place as long-term space holders. In patients with canalicular stenosis, a specially designed double bicanalicular tube was inserted for maximal dilatation of the lacrimal canals. The tubes are left in place as long as possible, ie, for months to several years. In cases in which there was recurrent obstruction following accidental tube extrusion, we simply inserted new tubes using a short-acting anesthesia. RESULTS: With 1 procedure, 17 (91%) of the eyes that were surgically treated for ductal stenosis became symptom free. The success rate in the cases of canalicular stenosis was 72%. In the remaining 28% of patients with recurrent obstruction, endonasal revision surgery was performed with new insertion of bicanalicular tubes. With the new tubes in place, these remaining patients have also stayed largely symptom free (length of follow-up, 8 months to 5 years [average, 3 years]). CONCLUSIONS: The routine insertion of bicanalicular tubes as long-term spacers has proved effective and has been tolerated without problems. A new aspect of our study is that in cases of canalicular stenosis or congenital agenesis of the lacrimal duct, which generally have a poor prognosis, the patients also benefit when our specially designed long-term double bicanalicular tubes are inserted in the lacrimal ducts.

Adolescent↗
PubMed1998

[Computer-assisted surgical navigation with a dynamic mobile framework for the nasal fossae, sinuses and base of the skull].

Surgery of the skull base and of the paranasal sinuses is often difficult because of the complex anatomy and the delicate structures; serious complications (loss of vision, cerebral lesion) have been reported. To improve the safety of such operations, computer-assisted navigation surgery is increasingly being put to use. We introduce the system which was developed in Berne. Our computer-assisted system is based on an intraoperative pursuit of the head and instruments which are equipped with infrared diodes and registered by an opto-electronic system-camera. The CT-acquisition of the head is accomplished framelessly without a head-holding device. This allows free movement of the head during surgery. Between March and November 1997, 35 navigation operations were performed for various pathologies at the anterior and lateral skull base. The majority of the cases were endonasal operations. No surgical complications occurred inspite of the complexity of the operations. The measured accuracy of the system between the CT and the actual instrument location in the patient was 0.5-2 mm (mean : < 1 mm) for the anterior skull base and 1-2.5 mm (mean < 1.5 mm) for the lateral skull base. The intraoperative navigation system allows identification of essential anatomical structures and permits safe and efficient surgery without additional loss of time. In addition, such a system allows minimal invasive approaches, and new operations may become possible.

Adult↗
PubMed1996

Descending necrotizing mediastinitis: surgical treatment via clamshell approach.

BACKGROUND: Descending necrotizing mediastinitis requires an early and aggressive surgical approach to reduce the high morbidity and mortality associated with this disease. The clamshell incision has provided excellent exposure of the entire mediastinum and both pleural cavities and was assessed in patients suffering from descending necrotizing mediastinitis. METHODS: Three patients with descending necrotizing mediastinitis and bilateral pleural empyema due to invasive streptococcal infections were operated on with this method. Radical debridement of the mediastinum and bilateral decortication was performed through a clamshell incision, including pericardiectomy in 2 patients. All patients received initially a high dose of antibiotic regimen, 2 had bilateral chest tube drainage, and 1 had mediastinal drainage and pleural debridement via cervical mediastinotomy and thoracoscopy, respectively. All these measures alone, however, failed to control the disease. RESULTS: The clamshell incision offered an excellent exposure for bilateral decortication and debridement of the entire mediastinum including pericardiectomy. One patient, who was referred in critically ill condition, died of multiorgan failure in the postoperative period. The remaining 2 patients recovered without further interventions and without evidence of phrenic nerve palsy, sternum osteomyelitis, or sternal override. CONCLUSIONS: The clamshell approach offers an excellent exposure for a complete one-stage surgical treatment with mediastinal debridement and bilateral decortication in patients suffering from descending necrotizing mediastinitis in the absence of profound septic shock.

Adolescent↗