Biomedical subjects

P Grunert

Publications and source records attributed to P Grunert.

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↗

PubMed2003

Symptomatic cysts of the cavum septi pellucidi and cavum vergae: the role of endoscopic neurosurgery in the treatment of four consecutive cases.

Cavum septi pellucidi and cavum vergae are generally asymptomatic fluid collections between the leaves of the septum pellucidum and are present in approximately 15 % of adult brains. These cavities rarely enlarge and become symptomatic causing significant neurological dysfunction as a result of obstruction of the interventricular foramina, distortion of the vascular structures of the deep venous system or compression of the hypothalamoseptal triangle. The authors present a series of four patients with symptoms related directly to pressure effects from the cyst wall to the neighbouring deep brain structures. There were two females and two males with a mean age of 47.5 years. All four patients underwent endoscopic cyst fenestration with a rigid endoscope. In 2 patients frameless neuronavigation was accomplished with the optical tracking system (Radionics, Burlington, USA). All symptoms related to pressure effect resolved after surgery. Endoscopic pellucidotomy of symptomatic cysts of the septum pellucidum produces immediate relief of the mass effect of the cyst and resolution of associated symptoms. Additionally, frameless neuronavigation is a useful tool in planning and realizing the approach and improving intraoperative orientation.

Adult↗

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

The "optimal" burr hole position for endoscopic third ventriculostomy: results from 31 stereotactically guided procedures.

ETV is a well established and successful method in contemporary neurosurgery. With growing experience there is a more efficient patient selection and further advances in technical know how. We evaluated retrospectively a consecutive group of 27 patients who were treated in our institution by stereotactic guided ETV between 1992 and 1996. When reviewing their postoperative imaging studies (MRI/CT) we could measure the position of the burr hole as port of entry for the rigid endoscope in 17 out of 23 finally selected patients. The median lateral position was 28 mm (mean 26.5 mm) from the midline and 8 mm (mean 6.5 mm) anterior of the coronal suture. We conclude that the optimal burr hole position should be 3 cm lateral to the midline and 1 cm anterior of the coronal suture, in the patients with normal anatomical findings.

Adolescent↗

PubMed1999

Accuracy of stereotactic coordinate transformation using a localisation frame and computed tomographic imaging. Part I. Influence of the mathematical and physical properties of the CT on the image of the rods of the localisation frame and the determination of their centres.

The accuracy of coordinate transformation from the computed tomographic (CT) space to the stereotactic frame space was analysed for frame-based stereotactic systems which use a localisation frame and coordinate transformation based on matrix calculation. The coordinate transformation was divided into three consecutive steps: (1) transforming the localisation frame into the CT image built up from pixels with distinct attenuation values, (2) determining the rod centres of the localisation frame in the CT image, and (3) coordinate transformation from the image to the frame space using the centres of the rods in the image space and algebraic, matrix-based calculation. The error contribution at each step was evaluated separately and its effect on the subsequent mathematical operations was analysed. The first step dealt with the influences of the mathematical and physical properties of the CT on the image of the localisation frame. Noise, slice thickness, convolution filter, dimension of the pixel matrix, and image processing had an influence on the attenuation values in each pixel. Above all, the slice thickness had an effect on the shape of the oblique rods in the CT image. At the second step, the main error contribution was due to the method by which the centre of the rods was calculated. The most accurate method was to determine the centre of gravity using the attenuation values as single mass points (with accuracy in the range of +/-1/10 pixel, or +/-0.125 mm), followed by rounding off the centre of gravity and the highest pixel value in the square matrix R2(N) within 1 pixel. Pointing with a cursor under visual control was accurate to 1 pixel and the pixel with the highest attenuation value showed deviations of up to 2 pixels in the x and y axes. Thus, the methods differed by a factor of 20. The influence of the CT mathematics and physics on the determination of the centre of the fiducials was negligible in comparison to the method of calculation used. There was no systemic error due to the filtred back projection algorithm. Data input errors due to noise were in the range of 1/10 pixel. The effects of the remaining physical influences were all in the range of the error due to noise. In particular these results speak in favour of no influence of slice thickness on coordinate transformation.

Artifacts↗

PubMed1999

Accuracy of stereotactic coordinate transformation using a localisation frame and computed tomographic imaging. Part II. Analysis of matrix-based coordinate transformation.

The accuracy of coordinate transformation from a CT image to a stereotactic frame was investigated for stereotactic systems using a localisation frame and matrix-based coordinate transformation. The main source of error influencing calculation was input data, due to inaccurate calculation of the centres of the rods of the localisation frame in the CT image, and the propagation of this input error during subsequent matrix calculation. Systemic errors during matrix calculation do not exist, and rounding off errors were of subordinate importance compared to the input data error. The influence of input data error on coordinate transformation was studied by geometric methods, computer simulation, and numerical analysis. In the geometric model, input data errors affected the calculation of the centres of the three oblique rods in the frame space and shifted them three points upwards or downwards on the axis of each rod. The three centres of the oblique rods defined the "CT plane" in the 3D space of the stereotactic frame. Displacements of these three centres caused a characteristic tilting of the CT plane. The positions of the correct and tilted CT planes defined the spatial error properties for all target points on the CT plane. The computer simulation investigated the effects on matrix-based transformation of all possible displacement combinations on the three oblique rods by 1 pixel (1. 16 mm) in the x and y directions. A characteristic, space-dependent distribution of the frame-related coordinates was obtained for each target point. In the centre of the frame, we found a maximal deviation of 1.0 mm in the xy direction and 2 mm in the z direction. This corresponded to an error amplification of 0.73 in the xy direction and 1.22 in the z direction relative to the error at the centres of the rods. The maximum deviation (found in the periphery) for all combinations on the three oblique rods was 1.7 mm in the xy direction and 3.3 mm in the z direction. This resulted in an amplification of 1.03 in the xy direction and 2.01 in the z direction. This results had to be multiplied by 2 to obtain a maximal error estimate for displacements including all nine rods of the localisation frame. Numerical analysis showed stable solutions with low error amplification for hexagonal frame arrangements.

Brain↗

PubMed1999

Frameless neuronavigation applied to endoscopic neurosurgery.

OBJECTIVE: We retrospectively analyzed the indications, surgical techniques, and applicability of frameless neuronavigation to endoscopic procedures in a heterogeneous group of 15 patients. MATERIAL AND METHODS: In 8 patients indications for surgery were cystic lesions, in 3 patients intraventricular tumors, and in 4 patients occlusive hydrocephalus. The mean age was 39 years (range 9-76 years). The follow-up period ranged from 5-24 months (mean 10 months). Frameless neuronavigation was accomplished with the "operating arm system" in 10 cases and with the "optical tracking system" in 5 cases (RADIONICS, Burlington, USA). RESULTS: In all 15 cases, neuronavigation sufficiently provided anatomical orientation, preoperative planning, and intraoperative realization of the approach. The calculated mean calibration error was 2.1 mm. There have been no permanent morbidities and no mortalities related to the use of endoscopes and neuronavigation. CONCLUSION: In endoscopic neurosurgery, frameless neuronavigation is a useful tool in planning and realizing the approach and improving intraoperative orientation in selected cases. Indications are small or hidden lesions, impaired visual conditions, abnormal anatomy, and narrow ventricles. Endoscopic procedures include fenestration and resection of intraventricular or intraparenchymal cysts, biopsy of intraventricular tumors, and third ventriculostomy in selected cases.

Adolescent↗

PubMed1999

Endoscopic third ventriculostomy: outcome analysis of 100 consecutive procedures.

OBJECTIVE: Endoscopic third ventriculostomy (ETV) has been shown to be a sufficient alternative in the surgical treatment of occlusive hydrocephalus. To elucidate the ongoing discussion of timing, indication, and surgical technique, a retrospective analysis of 100 consecutive ETVs was conducted. METHODS: One hundred ETVs were performed in 95 patients (43 female and 52 male patients). Their age ranged from 3 weeks to 77 years (mean age, 36 yr). Hydrocephalus was caused by aqueductal stenosis in 40 patients, space-occupying lesions in 42, and intraventricular or subarachnoid hemorrhage in 8. One patient had postinflammatory hydrocephalus, and four patients had occlusive hydrocephalus of unknown origin. In 33 cases, surgery was performed using stereotactic guidance. RESULTS: ETV was accomplished in 98 of 100 cases. The overall success rate was 76%. Patients with benign space-occupying lesions and nontumorous aqueductal stenosis had the highest success rates, which were 95 and 83%, respectively. Complications were arterial bleeding in one case, venous bleeding in three cases, intracerebral bleeding in one case, and infection in one case. There were no permanent morbidities or mortalities. CONCLUSION: ETV is most effective in treating uncomplicated occlusive hydrocephalus caused by aqueductal stenosis and space-occupying lesions. ETV is still effective in two-thirds of the patients with previous infections or intraventricular bleeding. Patients who have previously undergone shunting and who have occlusive hydrocephalus should undergo ETV at the time of shunt failure, with immediate ligation or removal of the shunt device. In selected cases of distorted anatomy or impaired visual conditions, stereotactic guidance is helpful.

Adolescent↗

PubMed1998

Basic principles and clinical applications of neuronavigation and intraoperative computed tomography.

Computed tomography (CT) images in combination with a navigation device enable three-dimensional (3-D) localization of intracranial lesions. Furthermore, CT scanning can be adapted for intraoperative application to actualize the image data and to check the anatomical situation during the operation. Frameless navigation was used in 100 patients. The procedure was performed in 46 cases with an optical navigation system, in 38 cases with a sensory arm, and in 16 cases with a navigated microscope. Six skin markers were used for registration. Mean fiducial registration error was 2.18 mm with a standard deviation of 1.03 mm. The indication for navigation was tumor localization and planning of the craniotomy in 81 cases, stereotactic biopsy in eight cases, and endoscopic procedures in 11 cases. Technical problems with the navigation system were observed in nine cases. In two additional cases the tumor was not found by navigation. All eight biopsy cases were successful, and histologically relevant specimens were obtained without complications. Navigation was helpful in 11 endoscopic cases for choosing an optimal trajectory through the foramen of Monro or for connecting multiple intraventricular cysts. For intraoperative CT imaging, the mobile Philips Tomoscan M was adapted to the needs of the operating environment. The mobile CT was used in 78 cases in the operating room: 16 patients who underwent a stereotactic procedure had only preoperative CT scans, 36 patients had an intraoperative CT during tumor surgery, and 26 patients during the test period of the device had only a postoperative CT investigation. In 10 cases (28%) of the intraoperative group the remaining tumor tissue could be demonstrated on the CT scans. The tumor remnants that were not visible in the microscopical surgical field were subsequently removed. According to our results, intraoperative navigation seems superior for the localization of intracranial lesions and intraoperative CT is more useful when considering the radicality of tumor removal.

Brain Neoplasms↗

PubMed1997

Gene cloning of rat and mouse platelet glycoprotein V: identification of megakaryocyte-specific promoters and demonstration of functional thrombin cleavage.

Platelet glycoprotein (GP) V is a major surface protein cleaved during thrombin-induced platelet activation. GPV associates noncovalently with the GPIb-IX complex to form GPIb-V-IX, a receptor for von Willebrand factor and thrombin. We describe the cloning of the genes coding for rat and mouse GPV and compare them with the human gene. The two rodent genes have a similar structure and resemble the human GPV gene with a coding sequence (approximately 1,700 nucleotides) entirely contained in one exon and a single intron (approximately 900 nucleotides) in the 5' untranslated region. Both genes have megakaryocyte-type promoters with conserved tandem Ets and GATA recognition motifs and lack a TATA box. The mature rat and mouse proteins comprise 551 amino acids, have 70% sequence identity, and contain an additional 8-amino acid intracellular segment as compared with the human protein. As in human GPV, there is an NH2-terminal leucine-rich region of 15 repeats and a thrombin cleavage recognition sequence. Whereas the rat and human thrombin cleavage sites are similar, the mouse cleavage site resembles that of the human thrombin receptor. Functionality of these sites was demonstrated by thrombin cleavage of synthetic peptides and analysis by high-performance liquid chromatography (HPLC) or mass spectrometry. Cleavage of native rat GPV was confirmed by means of a polyclonal antibody directed against the new NH2-terminal peptide exposed after thrombin cleavage. This antibody specifically recognized thrombin-activated rat platelets by fluorescence-activated cell sorting (FACS) analysis. In addition, we raised monoclonal antibodies specific for rat GPV (88 kD), which recognized the NH2-terminal soluble fragment (70 kD) liberated after thrombin cleavage. Knowledge of these rodent GPV genes and availability of species-specific peptides and antibodies will be essential to further studies aiming to define the exact in vivo function of platelet GPV using animal models of thrombosis and gene inactivation experiments.

Amino Acid Sequence↗

PubMed1997

Frame-based and frameless endoscopic procedures in the third ventricle.

Stereotactic guidance is useful for planning an accurate trajectory to the third ventricle. A guiding block with a ball joint was developed for frame-based endoscopy and adaptors for arm-based and armless navigation systems. Between 1992 and 1996, 52 patients were operated on endoscopically in the third ventricle under stereotactic guidance. Thirty-eight ventriculostomies, 13 biopsies and 10 cystic lesions were performed. The coordinates of two points were calculated; one in the foramen of Monro and the second in the third ventricle. The ventriculostomy was performed under endoscopic control bluntly with a Fogarty catheter in front of the basilar artery. Twenty-seven (71%) of the patients had a long-lasting benefit from the operation, 6 (16%) had no benefit, and in 5 (13%) a shunt operation was necessary. Poor outcome was due to closure of the stoma by tumor growth or infection. Three cysts were fenestrated and 7 colloid cysts partly evacuated. One incident of bleeding occurred in the frontal lobe in the path of the endoscope which was treated conservatively with success. Transient memory deficit was noted in one patient and double vision in the second.

Adolescent↗