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R Filippi

Publications and source records attributed to R Filippi.

At least 19 recordsLinked to original sources
PubMed2003

Computer-aided navigation in neurosurgery.

The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the technical error of the device calculating its own position in space, the registration error due to inaccuracies in the calculation of the transformation matrix between the navigation and the image space, and the application error caused additionally by anatomical shift of the brain structures during operation. In the third part the main clinical fields of application in modern neurosurgery are demonstrated, such as localisation of small intracranial lesions, skull-base surgery, intracerebral biopsies, intracranial endoscopy, functional neurosurgery and spinal navigation. At the end of the article some possible objections to navigation-aided surgery are discussed.

Equipment Design↗
PubMed2003

The role of third ventriculostomy in the management of obstructive hydrocephalus.

OBJECTIVE: Endoscopic third ventriculostomy (ETV) is an effective treatment for occlusive hydrocephalus caused by an obstruction of the CSF flow in the aqueduct or the posterior fossa. We evaluated the factors age, pathology and surgical technique on the results of the ETV. METHODS: Between November 1992 and October 2000 171 ETV have been performed in 159 patients. The follow-up was evaluated in 150 patients. The age ranged from 10 days to 77 years (mean age 35 years). The hydrocephalus was caused by benign aqueductal stenosis in 77 patients, space-occupying lesions in 59, by intraventricular hemorrhages in 11, and by other causes in 3 patients. The trajectory was planned in 31 patients by frame-based and in 4 patients by frameless stereotaxy. RESULTS: The overall success rate of a single ETV was 71.3 % and including successful re-ETV 76.7 %. Best results were observed in adults and children older than 1 year. Infants demonstrated significantly worser outcomes. Patients with benign aqueductal stenosis and tumor compressing the aqueduct had the greatest profit from the ETV. The stereotactic guidance had no influence on the outcome and the number of severe complications. Complications were one arterial bleeding, three venous bleedings, and one ICB, all without permanent deficit, except one permanent hemiparesis. No mortality was observed.

Adolescent↗
PubMed2002

Frame-based and frameless stereotaxy in the localization of cavernous angiomas.

Cavernous angiomas are mostly small intracranial vascular lesions which can be intraoperatively localized by sonography or stereotactic methods. This paper compares the results of cavernous angioma surgery localized by frame-based vs frameless techniques. Thirty-nine patients with cortical or subcortical lobar cavernoma were operated on by a microsurgical trans-sulcal approach. The localization of the lesion was performed in 19 (49%) patients by frame-based technique and in 20 (51%) patients by frameless navigation. In 22 (56%) of the patients, the cavernomas were located in an eloquent cortical area. Ten of 22 of these lesions were localized by frame-based stereotaxy and 12/22 by frameless navigation. The patients demonstrated the following preoperative symptoms: seizures 20 (51%), hemorrhage 18 (46%), focal neurologic deficit 11 (28%), and headache three (7%), and three (7%) were asymptomatic. Thirteen of 19 patients localized with frame-based stereotaxy were postoperatively asymptomatic or their preoperative neurological symptoms improved. Four of 19 had a transitory neurologic deficit and 2/19 a permanent worsening. Seventeen of 20 patients localized by frameless navigation were asymptomatic or neurologically improved. Three out of 20 suffered from a transient neurologic deficit. Regarding the seizures, 14 (70%) patients were postoperatively free of seizures, three (15%) were improved, and three (15%) were unchanged. The frameless navigation was superior regarding the flexibility for approaches along the skull base and midline, and the frame-based method was superior regarding the accuracy for very small lesions (less than 7 mm). In other cases, both methods were equal. Frame-based and frameless stereotactic methods are useful in the localization of small cavernous angiomas. They make it possible to remove cavernous angiomas in eloquent cortical regions with low risk of a permanent neurologic deficit.

Adolescent↗
PubMed2002

Stereotactic biopsies guided by an optical navigation system: technique and clinical experience.

Frame-based stereotactic biopsies are time-consuming procedures making necessary head fixation in a ring, explicit coordinate calculation and setting of the parameters. Frameless systems make many of these intermediate steps unnecessary, impose less mechanical restrictions regarding access to the lesions, and with slight modifications can be used to perform stereotactic biopsies. A special adaptation designed to fix the holder and the biopsy instrument is described. The neuronavigation optical tracking system of Radionics was used. CT scans were performed with 6 skin markers. Calibration was performed after head fixation in the Mayfield clamp. Mean calibration error was 2.19 +/- 0.81 mm. The light-emitting diode holder of the pointer was fixed into 2 Leila arms and moved under visual control based on CT images. The target point was selected, Leila arms fixed and a burr hole performed. The cannula was introduced to the target, being fitted with a depth stop in a length identical to that of the pointer on the screen. If necessary a second trajectory was easily selected. 49 patients underwent a frameless stereotactic biopsy. All targets except seven were superficial or in the white matter. In selected cases the biopsies were taken from deep-seated lesions. A histological diagnosis was obtained in 100 % of the cases. Four cases deteriorated postoperatively, two of these related to intratumoral bleeding. Navigation is a simple and effective method to perform biopsies of superficial and relatively large lesions. Frame-based procedures are restricted to brainstem tumors and lesions less than 1.5 cm in diameter.

Adolescent↗
PubMed2002

Uniportal endoscopic surgery of carpal tunnel syndrome: technique and clinical results.

The endoscopic carpal tunnel release is a new minimally invasive method which has been used to decompress the median nerve in the carpal tunnel for the past decade. Advantages of this method should be a decreased postoperative morbidity and earlier return to work. Preoperative complaints, postoperative results and complications of the therapy for a total of 60 patients are presented. All endoscopic releases were performed using the Agee uniportal technique. The overall success rate in our study was 56/60 (93.3 %). 47/54 (87.0 %) patients were completely free of pain after endoscopic surgery. An improvement in preoperative pain was noted in 4/54 (7.4 %) patients. Hypesthesia and dysesthesia disappeared totally in 39/46 (84.8 %) patients. An improvement of the sensible disturbances was observed in 4/46 (8.7 %) cases. 10/13 (76.9 %) preoperative pareses recovered completely, 3/13 (23.1 %) remained unchanged. The complication rate in total in our series was 4/60 (6.7 %), thereof 3 cases of post-operative infection (5 %) and one serious median nerve injury (1.7 %). The mean time for return to work was 29 days. Summing up, it may be said that monoportal endoscopic carpal tunnel release appears to be an effective and safe minimally invasive method for the treatment of carpal tunnel syndrome.

Adult↗
PubMed2002

Re-ventriculostomy for treatment of obstructive hydrocephalus in cases of stoma dysfunction.

In this article, 12 re-ventriculostomies in the treatment for obstructive hydrocephalus are described. The etiology of the hydrocephalus was a benign aqueductal stenosis in 9 patients, a tumor around the aqueduct in 2 patients and intraventricular bleeding in one patient. In all cases the initial ventriculostomy was successful, but after a time interval of 2 weeks to 6 years the patients developed similar clinical symptoms as preoperatively. In all except one case the radiological findings spoke in favour of stoma closure. Intraoperatively the stoma was completely closed in 9 patients and in 3 patients a subtotal closure was observed. In all cases a re-ventriculostomy was performed bluntly with a Fogarty catheter in loco typico at the floor of the third ventricle. Of the 12 patients 6 had an excellent outcome postoperatively, one patient improved and one had a benefit from the re-ventriculostomy although he died of cardiac problems. In the remaining 4 patients the re-ventriculostomy was not successful and the patients needed a shunt operation. In conclusion, after initially successful endoscopic third ventriculostomy, re-ventriculostomy should be considered as a sufficient treatment option in case of suspected stoma dysfunction.

Adolescent↗
PubMed2002

Cubital tunnel syndrome. Treatment by decompression without transposition of ulnar nerve.

Cubital tunnel syndrome is the second most common entrapment neuropathy in the upper limb; however, surgical treatment of the ulnar nerve entrapment at the elbow remains controversial. None of the presently advocated procedures (simple decompression of the ulnar nerve, medial epicondylectomy, subcutaneous, submuscular or intramuscular anterior transposition of the ulnar nerve) has proven optimal regarding long-term results. This paper presents the experience of treating cubital tunnel syndrome with simple decompression in 40 patients. Three months after surgery 23/36 patients did not feel any pain in their operated hands. In 11/36 cases we observed an improvement of preoperative pain. Sensory disturbances disappeared completely in 24/40 cases. 11/40 patients reported an improvement of preoperative dysesthesia or hypesthesia. In 12/22 patients we observed complete recovery of preoperative pareses of adductor muscle of thumb or hypothenar muscles weakness. 7/22 cases demonstrated an improvement of these pareses. In total 28 patients (70 %) had an excellent outcome without residual symptoms. For 5 patients treatment results were classified as good with slight residual pain and sensory disturbance (12.5 %). In 4 cases (10 %) we only observed a fair outcome with persistent severe sensory and motor deficits but slow improvement over the last three months. Three patients did not demonstrate any improvement (7.5 %). The mean duration of postoperative disablement in our working patients (18/40) was 28 days. In summary, simple decompression of the ulnar nerve seems to be an adequate and successful minimally invasive technique for the treatment of cubital tunnel syndrome.

Adult↗
PubMed2001

Bovine pericardium for duraplasty: clinical results in 32 patients.

Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report on the use of solvent-preserved, gamma-sterilized Tutoplast bovine pericardium for dural grafts in 32 patients undergoing cranial and spinal operations with the objective of clinically assessing this material and technique by a retrospective analysis. All available records were reviewed and information regarding the indication for grafting, complications, and outcome were collected and analyzed for all patients. Indications for grafting included tethered cord myelolysis, closure of lumbosacral myeloceles, Chiari decompression, posterior fossa craniotomy, supratentorial craniotomy, and trauma. Outcomes were excellent in 31 patients; the one poor outcome was unrelated to surgical closure. The dural graft was not intended for outcome in any patient. Bovine pericardium was found to be a flexible and easily suturable, safe and cost-effective material for duraplasty. These results confirm the excellent suitability of Tutoplast bovine pericardium for dural substitution.

Adolescent↗
PubMed2001

Recurrent cubital tunnel syndrome. Etiology and treatment.

Controversy surrounds the treatment of recurrent cubital tunnel syndrome after previous surgery. Irrespective of the surgical technique, namely pure decompression in the ulnar groove and the cubital tunnel distal of the medial epicondyle, and the different methods of volar transposition (subcutaneous, intramuscular, and submuscular), the results of surgical therapy of cubital tunnel syndrome are often not favorable, especially in cases of long-standing symptoms and severe deficits. Twenty-two patients who had previously undergone surgical treatment for ulnar nerve entrapment at the elbow were evaluated because of persistent or recurrent pain, paresthesia, numbness, and motor weakness. Ten patients had undergone a nerve transposition, 5 patients underwent a simple decompression of the ulnar nerve, and 7 patients experienced two previous operations with different surgical techniques. Two patients underwent surgery at our hospital, whereas 20 patients underwent their primary surgery at other institutions. Various surgical techniques were used during the subsequent surgery, such as external neurolysis, subcutaneous anterior transposition, and subsequent transfer of the nerve back into the sulcus. The causes of continued or recurrent symptoms after initial surgery included dense perineural fibrosis of the nerve after subcutaneous transposition, adhesions of the nerve to the medial epicondyle and retention of the medial intermuscular septum. The average follow-up after the last procedure was 7 months (2 - 20 months). All 7 patients with subsequent transfer of the ulnar nerve back into the sulcus became pain-free, whereas only 11 of 15 patients who had external neurolysis or subcutaneous transposition became free of pain or experienced reduced pain. The recovery of motor function and return of sensibility were variable and unpredictable. In summary, reoperation after primary surgery of cubital tunnel syndrome gave satisfactory results in 18 of 22 cases. Subsequent transfer of the ulnar nerve back into the sulcus promises to be useful in cases in which subcutaneous transposition had not been successful.

Adult↗
PubMed2000

Brain tissue pO2 related to SjvO2, ICP, and CPP in severe brain injury.

The aim of this report is to present first experience in comparing the course of brain tissue oxygen pressure values (PtiO2) to changes in jugular vein oxygen saturation (SjvO2), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) after severe brain injury. PtiO2 monitoring was done using a polarographic Clark type microcatheter (LICOX pO2 probe) (GMS, Kiel, Germany) with a diameter of 0.5 mm and a sensitive area 7.9 mm long inserted in a right frontal position. The microcatheter was connected to a LICOX pO2 device. A fiber-optic catheter was used to measure SjvO2 and placed into the right internal jugular vein. The ICP monitoring was performed with a fiber-optic intraparenchymal device (Camino Laboratories, San Diego, Calif.) inserted in a left frontal position. Consistent correlations could be noticed between reduced PtiO2 and higher ICP and lower CPP levels. However, the absolute value of a single SjvO2 data point seemed to be less relevant diagnostically than its trend over a period of time. Owing to their experience, the authors suppose that PtiO2 monitoring will be a very important and reliable tool in the treatment of brain injury in the future, especially in its correlation to ICP and CPP.

Adolescent↗
PubMed2000

Tightness of duraplasty in rabbits: a comparative study.

OBJECTIVE: The purpose of this study was to test, in rabbits, the tightness of seven dural substitution materials commonly used in neurosurgery, i.e., Lyodura (B. Braun Melsungen AG, Melsungen, Germany), Tutoplast dura (Tutogen Medical, Inc., Parsippany, NJ), Tutoplast fascia lata (Tutogen Medical, Inc.), autologous periosteum, Neuropatch (B. Braun Melsungen AG), Dacron (E.I. du Pont de Nemours and Co., Wilmington, DE), and Ethisorb (Ethicon, Inc., Somerville, NJ). METHODS: Duraplasties were performed with sutures alone or were additionally fixed with fibrin glue. Leakage pressures were assessed by infusion of artificial cerebrospinal fluid, containing sodium fluorescein, into the cisterna magna and detection of fluorescence using a charge-coupled display camera with background substraction, 3 days, 3 weeks, or 3 months after surgery. RESULTS: Three days after implantation, the mean tightness values of duraplasties with Lyodura or Neuropatch were significantly higher (P = 0.007) than the values for the other substitutes. A significant improvement of tightness with increasing implantation time could be demonstrated for autologous periosteum (P = 0.0063). Improvement of tightness with the use of fibrin glue could be proven only for the heterologous grafts (P = 0.0071). The tightness values for Neuropatch fixed only with sutures were similar to those for the best heterologous substitutes implanted with additional fibrin glue. Lyodura, Tutoplast dura, and Neuropatch demonstrated favorable implantation characteristics; they were thin, flexible, and easily suturable. Neither adhesions to the brain nor space-occupying scars were noted. CONCLUSION: These results confirm the excellent suitability of Lyodura and Neuropatch for dural substitution.

Animals↗
PubMed1999

Postoperative pain therapy after lumbar disc surgery.

OBJECT: This study was undertaken to determine whether a special postoperative pain administration of tramadol and diclofenac provides any benefits in patients who underwent microsurgical lumbar discectomy. METHODS: The study consisted of 60 patients undergoing microsurgical lumbar discectomy. Patients were randomly divided into two groups based on the postoperative pain management: 1) Group A (n = 30); no standardized pain therapy; these patients received on demand different analgesics and at variable dosages which were selected by the neurosurgeons; 2) Group B (n = 30); standardized pain therapy with specific dosages of tramadol and diclofenac in regular time intervals during the first 48 hours after surgery. After surgery follow-up data from a special standardized questionnaire were obtained for all 60 patients during the first 48-72 postoperative hours. The patients were asked for course and intensity of pain as well as about some specific circumstances of clinical therapy after surgery. The postoperative pain intensity of patients treated with the special combination of tramadol and diclofenac was significantly diminished (24 hours after surgery: p = 0.0002, 48 h: p = 0.0047, 72 h: p = 0.0034) in relation to the group without standardized pain therapy. Similarly, the frequency of breakthrough pain was significantly reduced (24 h: p = 0.0001, 48 h: p = 0.003, 72 h: p = 0.004). CONCLUSIONS: The results suggest that the application of tramadol and diclofenac during the first 48 hours after lumbar microdiscectomy results in a reduction in postoperative pain without complications. We suggest that the use of this combination can be a beneficial adjunct to lumbar disc surgery.

Adult↗