Biomedical subjects

L Klimek

Publications and source records attributed to L Klimek.

At least 19 recordsLinked to original sources

PubMed1996

Endoscopic surgery of the rhinobasis with a computer-assisted localizer.

The endoscope is useful for the diagnosis and surgical therapy of diseases of the nose, the paranasal sinuses and its neighboring regions, and allows for microinvasive, functional approaches. The reduced invasiveness of therapeutic procedures is sometimes accompanied by insufficient clearness of the surgical field, however. This significant problem is solved by the computer-assisted-surgery (CAS) system, an intraoperative localizer. It allows continuous orientation based on three-dimensional reconstructed preoperative CT scans with superimposed positioning of the endoscope. We have now adapted CAS for endoscopic sinus surgery, which meant that a variety of visualization methods were tested. A conventional straightforward endoscope was used in combination with, or as, the localizing probe. A dual-display technique was adjusted to video-endoscopic procedures: the information of the localizer is displayed on one monitor while the video-endoscopic picture is viewed on a second screen. In addition, a single-display technique with both images on one monitor was developed. It proved to be the most promising way of combining endoscopy and intraoperative CT-image-guided localization.

Endoscopes↗

PubMed1996

[Cell activation markers in rhinitis and rhinosinusitis. 1: Eosinophilic cationic protein (ECP)].

BACKGROUND: The quantitative analysis of the migration and activation of inflammatory cells is standard in current diagnosis of inflammatory diseases of the nasal mucosa. Histological and cytological examinations are mostly used for this purpose. Development and validation of assays for specific marker proteins of the different cell populations make similar analyses possible from nasal secretion samples. Myeloperoxidase (MPO) or Elastase are important markers for neutrophil granulocytes as is Tryptase for mast cells, Lysozyme for macrophages/monocytes and Eosinophil Cationic Protein (ECP). Eosinophil Neurotoxin/Eosinophil Protein X (EDN/EPX) or Major Basic Protein (MBP) for eosinophil granulocytes. METHODS: We performed a prospective study on healthy volunteers and patients with different inflammatory nasal and paranasal sinus diseases and analysed such cell activation markers in nasal secretions. In the healthy volunteers, 183 nasal secretion samples were obtained. A total of 515 samples were obtained in patients with the diagnosis: chronic sinusitis (n = 49), allergic rhinitis to perennial allergens (n = 94), chronic sinusitis with additional allergic rhinitis to perennial allergens (n = 36), nasal polyps (n = 28), allergic rhinitis to seasonal allergens extraseasonally (n = 131), and allergic rhinitis to seasonal allergens during the pollen season (n = 177). RESULTS: In part I of this paper we describe the results for the Eosinophil Cationic Protein (ECP). In all patients with active inflammatory reactions significantly higher ECP levels than in the controls were found. Moreover, ECP levels differed between the diseases investigated. CONCLUSIONS: ECP nasal secretion level seem to be a valuable marker for the assessment of nasal eosinophilic inflammation and might become an adjunct to current diagnostic measures.

Adult↗

PubMed1996

Sedation in allergic rhinitis is caused by the condition and not by antihistamine treatment.

Sedation is regarded as a common side-effect of most H1-antihistamines. This view must be accepted, yet can hardly be assessed under treatment of allergic disorders. Since central sedative potency is hard to evaluate, different methods of measurement have been introduced in the four phases of clinical investigation. While tests of high complexity in early trials can detect true central effects, they seem to have the disadvantage of not taking into consideration the important interactions of drugs with the disorder. Therefore, we used a visual analog scale (VAS) as an instrument to demonstrate sedative effects in five clinical studies carried out between 1989 and 1994 with a total number of 1070 patients. Thereby, we could assess the result of the different components of the central interaction. In 1989, in a double-blind, placebo-controlled trial, we could show that the vigilance of patients suffering from seasonal allergic rhinitis increased significantly more under treatment with an antihistamine (mizolastine) than under placebo. From 1992 until 1994, we compared azelastine nasal spray either by the double-dummy technique with oral antihistamines (cetirizine, loratadine, and astemizole) or by the double-dummy or placebo-controlled design with monotherapy or combined therapy with azelastine tablets. A marked or statistically significant improvement of vigilance was found for all compounds (loratadine: P < 0.0001; cetirizine: P < 0.0254; and azelastine nasal spray: P < 0.1409 to P < 0.0001). Even when taking azelastine as oral application, patients, in spite of the warning, reported a similar increase in vigilance (P < 0.2628 to P < 0.0001). Finally, we assessed the range of physiologic vigilance using the same VAS in healthy volunteers. In conclusion, we could prove that in all trials the baseline values of vigilance of untreated symptomatic patients were far below physiologic condition and improved under treatment to the upper range of healthy persons. Therefore, any sedative properties of modern H1-antihistamines should not limit their therapeutic use, since the truly threatening sedation results from the disorder itself.

Arousal↗

PubMed1996

Increased in vitro cysteinyl leukotriene release from blood leukocytes in patients with asthma, nasal polyps, and aspirin intolerance.

In vitro cysteinyl leukotriene (cLT) release from blood leukocytes was measured in eight normal individuals (NI), nine patients with nasal polyps (NP) without aspirin intolerance, and eight patients with NP, asthma, and aspirin intolerance (AI). Blood leukocytes were prestimulated with interleukin-3 (IL-3) and incubated with acetylsalicylic acid (ASA) (10 and 100 micrograms/ml) together with C5a (10(-8) mol/l) for 18 h. cLT release (LTC4, LTD4 and LTE4) from blood leukocytes was measured with a competitive enzyme-linked immunoassay. Background cLT release was 259 +/- 66 pg/ml (mean +/- SEM) in the NI group, 185 +/- 33 pg/ml in the NP group, and 578 +/- 136 pg/ml in the AI group (P = 0.1). After incubation with 10 micrograms/ml ASA, cLT concentration was lower in normal subjects (346 +/- 72 pg/ml) and in patients with NP (209 +/- 53) than in patients with AI (686 +/- 75 pg/ml, P = 0.002). After incubation with 100 micrograms/ml ASA, cLT concentrations were 285 +/- 72 pg/ml in the NI group, 313 +/- 77 pg/ml in the NP group, and 654 +/- 121 pg/ml in the AI group (P = 0.04), respectively. Simultaneous incubation with ASA 10 micrograms/ml and C5a (10(-8)mol/l) resulted in a cLT concentration of 751 +/- 171 pg/ml in the NI group, 343 +/- 102 pg/ml in the NP group, and 2196 +/- 480 pg/ml in patients with AI (P = 0.0006), whereas simultaneous incubation with ASA 100 g/ml and C5a (10(-8)mol/l) resulted in 268 +/- 51 pg/ml in the NI group, 412 +/- 97 pg/ml in the NP group, and 1701 +/- 368 pg/ml in the AI group (P = 0.005). In patients with AI, cLT release from blood leukocytes is altered when compared with normals and patients with NP. The presented cLT-release assay could be of potential use in the in vitro diagnosis of AI.

Adult↗

PubMed1995

Computer-assisted image-guided surgery in pediatric skull-base procedures.

Skull-base surgery is characterized by the variety of important neural and vascular structures within a narrow operating field. Although preoperative imaging by computed tomography (CT) and magnetic resonance imaging (MRI) and the use of microsurgical techniques have improved intraoperative orientation, a large number of complications still are caused by localization problems. Especially in pediatric skull-base surgery, maximum localization accuracy during surgery is required. The authors developed a localizing system based on tomographic imaging (such as CT or MRI) to achieve safer surgery by providing highly accurate location information. The preliminary successful experience in the use of the Aachen computer-assisted surgery device for pediatric skull-base surgery (14 cases) is presented. Indication include juvenile angiofibroma of the nasopharynx, infectious and tumorous diseases of the paranasal sinuses, orbital tumors, foreign bodies, and intracranial abscess formation.

Adolescent↗

PubMed1995

Image- and model-based surgical planning in otolaryngology.

Preoperative evaluation of any operating field is essential for the preparation of surgical procedures. The relationship between pathology and adjacent structures, and anatomically dangerous sites need to be analyzed for the determination of intraoperative action. For the simulation of surgery using three-dimensional imaging or individually manufactured plastic patient models, the authors have worked out different procedures. A total of 481 surgical interventions in the maxillofacial region, paranasal sinuses, orbit, and the anterior and middle skull base, in addition to neurotologic procedures were presurgically simulated using three-dimensional imaging and image manipulation. An intraoperative simulation device, part of the Aachen Computer-Assisted Surgery System, had been applied in 407 of these cases. In seven patients, stereolithography was used to create plastic patient models for the preparation of reconstructive surgery and prostheses fabrication. The disadvantages of this process include time and cost; however, the advantages included (1) a better understanding of the anatomic relationships, (2) the feasibility of presurgical simulation of the prevailing procedure, (3) an improved intraoperative localization accuracy, (4) prostheses fabrication in reconstructive procedures with an approach to more accuracy, (5) permanent recordings for future requirements or reconstructions, and (6) improved residency education.

Child↗

PubMed1994

[Extraction of orbital foreign bodies using a new kind of image processing system].

We present a new localization system in orbital surgery. The procedure is based on the linkage of two methods. A preoperative thin-layer CT scan is taken and the image data are fed into a high-capacity computer which computes a three-dimensional model of the orbit. Intraoperatively, the volume model of the skull is linked to a mechanical arm for position measurement. Surgical instruments can be mounted to this arm. The computer then projects the position of the instrument into the volume model of the orbit, so that the surgeon can follow the movements of his instruments on the monitor. The surgeon has a means of checking position that comes close to constant intraoperative CT monitoring. Thereby the surgeon is able to localize even small foreign bodies without extensive explorations. We present six patients in whom orbital foreign bodies had to be extracted during the past 5 years. A 44-year-old man had an iron foreign body; the external wound was treated surgically elsewhere. Two patients (25 and 22 years old) had glass foreign bodies; in one of them the splinters were not seen using conventional X-ray. Choosing the exact level with the Hounsfield window, the foreign bodies could be demonstrated on the monitor. In three patients with orbital fractures and compression of the optic nerve, dislocated bone splinters were extracted. The localization of those splinters was easy using the imaging system, but would have been rather difficult by other means.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Frameless stereotactic drainage of intracranial abscesses.

Our preliminary experience is presented in the use of the Aachen Computer-Assisted Surgery device for frameless stereotactic puncture and drainage of intracranial abscesses through a 2.1-mm twist-drill hole. The apparatus and technique are described, along with the results of its use in 2 patients. Intraoperatively the semiactive system presents a schematic display of the drainage probe projected into a 3D model of the situs on the monitor screen corresponding to the instrument's position. As the surgeon directs the probe into the abscess the corresponding section is displayed. Thereby drainage is easily achieved under visual control.

Adult↗

PubMed1993

Correlation between clinical, angiographic and transcranial Doppler sonographic findings in patients with moyamoya disease.

Nine patients with Moyamoya disease were followed by the authors between 1982 and 1991. The patients were investigated with transcranial Doppler sonography (TCD), angiography and clinically. Two patients were treated conservatively. Bilateral extra-intracranial (EC-IC) anastomosis was performed in 4 patients; in 2 patients bypass surgery was performed unilaterally. One patient with an aneurysm of the carotid artery presented a subarachnoidal haemorrhage. There was a good correlation between TCD and angiographical findings in all patients. In four patients indication for bypass surgery was established by TCD. All patients who underwent EC-IC bypass surgery improved clinically; the symptoms disappeared in three patients and improved markedly in two patients. Transcranial Doppler sonography is proven to be a reliable atraumatic tool in diagnosis, indication for treatment and postoperative follow-up in patients with moyamoya disease.

Adult↗

PubMed1993

[Orbital decompression by pterional approach in dysthyroid orbitopathies].

The etiology of the endocrine orbitopathy is still unknown and thereby their treatment remains symptomatic. The surgical decompression is achieved in resecting lateral wall, roof and partly bottom of the orbit. We treated 23 eyes in 14 patients and in only one patient the decompression obtained with this method was insufficient. This patient underwent additionally transantral transethmoidal decompression. One patient had a complete loss of vision after surgery probably due to direct lesion of the optic nerve. The decompression of the orbit is indicated in fast progressive endocrine orbitopathies with impairment of the visual function.

Adult↗

PubMed1993

[Prevention of vascular complications in endonasal paranasal sinus surgery. Part II: Pre- and intraoperative imaging].

Computer-assisted surgery (CAS) is a new intraoperative localization system that is based on digital image generation devices. The system has been used in 189 cases of paranasal sinus procedures, employing computed tomography (CT) image data. Highly accurate imaging and localization of bony structures can be achieved in this way, although definition of vascular structures is limited by representation attributes of vessels in CT. Algorithms have now been developed for the use of magnetic resonance angiography (MRA) data with the system. CAS was used in six cases of endonasal surgery. Imaging helped substantially in all cases, but its application was limited by incomplete reflection of small vessels. In one case, intraoperative findings showed MRA-inherent inaccuracies. These might be avoided using correction programs and phantom selection (shimming) procedures in the future. Additionally, matching of different imaging modalities should improve intraoperative applications of CAS.

Algorithms↗

PubMed1993

Stereolithographic modelling for reconstructive head surgery.

Until now, bounds of model creation of medical objects had to be set because of the limited capabilities of available manufacturing equipment. Recently, stereolithography was developed as an alternative to current milling operations. In this process the surface of a photohardening liquid plastic compound is traced by a laser beam and hardened in layers. The models thus produced are extremely accurate and retain excellent detail. Specific implants can be designed and prepared as is illustrated in a case report. If tissue-compatible plastics are used, custom-made implants could soon be manufactured directly with the technique described.

Child↗

PubMed1993

[Nosocomial infections in a neurosurgical intensive care unit].

The occurrence of nosocomial infections in 1017 consecutive patients seen in a neurosurgical intensive care unit (ICU), over a period of 18 months is reported. The frequency of infections is low, which may possibly be due partly to the short stay in the ICU. Close interdisciplinary cooperation is stressed as an important factor in limiting infections. BACKGROUND. The aim of this study was to analyse the nosocomial infections in a neurosurgical intensive care unit over a period of 18 months, emphasizing localization and cause of infection, in order to adapt treatment and to take preventive measures. From 15% to 27% of patients treated in ICUs acquire nosocomial infections. In Germany this means 500,000-800,000 patients a year, and the annual costs related to nosocomial infections are estimated at 1.7 billion Deutschmarks. PATIENTS AND METHODS. In all, 1017 consecutive patients were evaluated. The patients were divided into two groups, depending on the duration of treatment in the ICU: Patients who remained for less than 48 h (1017 patients) Patients who were treated for a period exceeding 48 h (314 patients) The evaluation was performed retrospectively from the medical documentation. Criteria for registration are those of the Centers for Disease Control (Atlanta 1988). When more than one infection was diagnosed, each was considered as a new infection, regardless of the bacteria involved. Among the 314 patients who were in the ICU for more than 48 h a total of 114 nosocomial infections were recorded. The frequency of infection referred to all patients treated during that time (n = 1017) was 11.2%, while the frequency among those who were treated for longer than 48 h was 36.3%. Most infections (38.6%) affected the respiratory tract, followed by infections of the urinary tract. Of the bacteria determined 56.7% were gram-negative. In this group E. coli was the most frequently found (29.8%). In the group of gram-positive bacteria, S. aureus was diagnosed in 56.3% of cases. Twelve (16%) of the infected patients died and lethality referred to all patients was 8.6%. DISCUSSION. Compared with other studies, this study revealed a low the infection rate, at 11.2%. This can be explained partly by the short stay in this ICU (mean 3.7 days) and partly by the retrospective method of registration and the particular medical characteristics of neurosurgical patients. The well-known general risk factors for infection, such as age, mechanical ventilation, continuous catheterization of the bladder, and long duration of stay, are also found in neurosurgical ICUs. It is quite difficult to determine to what extent nosocomial infections prolong the treatment necessitated by the primary neurosurgical disease. We were not able to extrapolate the influence of immunosuppressant treatment on the appearance of nosocomial infections, as almost all patients in this study were receiving steroids. This study underlines the necessity of interdisciplinary cooperation between neurosurgeons, anaesthesiologists, microbiologists and nurses in neurosurgical ICUs, where most patients staying longer than 48 h are immunosuppressed and ventilated and thereby particularly at risk of nosocomial infections.

Costs and Cost Analysis↗

PubMed1993

Surgical or medical treatment of questionable peritonsillar abscess? The use of B-mode ultrasonography.

A prospective study was carried out to evaluate the sensitivity of sonography in the diagnosis of peritonsillar abscesses (quinsy). From 1986 to 1991 all cases of clinically doubtful peritonsillitis were subjected to B-Mode ultrasonography of the tonsils before tonsillectomy. 118 patients were examined. Sensitivity of the method in cases of clinically uncertain peritonsillar abscesses was 87%. The predictive value of the method was calculated to be 0.89; however only five false positive cases ("abscess" in ultrasound but no pus during surgery) were found. We therefore suggest that all patients suffering from questionable peritonsillitis should be examined by ultrasound. If abscess formation is suspected, surgical intervention is indicated. In all other cases I.V. antibiotics should be administered and control sonography should be carried out.

Adolescent↗

PubMed1993

Computer-assisted orbital surgery.

In orbital surgery, deep lesions must be operated on through extremely small approaches. We developed a method (Computer Assisted Surgery or CAS) designed to achieve safer and more precise surgery by providing highly accurate intraoperative information regarding the location of the surgical instrument. The device involved consists of a high-capacity computer that processes computed tomographic (CT) data in real time, connected to a mechanical measuring arm attached to the surgical instrument. From the CT data, the computer calculates a three-dimensional reconstruction and displays the tip of the instrument as a reticle in this model. Using the CAS system, the surgeon is continuously apprised of the precise position of the surgical instrument vis-a-vis all relevant anatomical structures. We have used CAS successfully in 21 cases of orbital surgery. We have found the system especially useful in dealing with deep-seated tumors, either for biopsy or surgery; in performing orbital and optic nerve decompression; in localizing deep-seated foreign bodies; and in all cases of impaired orientation due to severe bleeding, tumor-destroyed landmarks, or preoperated anatomy. Although the number of patients is too small to yield statistically significant data allowing a comparison of patient outcomes with and without using the system, we have just begun a large prospective clinical trial designed to provide such data.

Adolescent↗

PubMed1993

[How badly does the "normal-hearing" young man of 1992 hear in the high frequency range?].

In the course of a clinical study we examined young men believed to have normal hearing. Volunteers with a positive history for noise deafness were excluded from further study. Normal hearing was verified by pure-tone audiometry if the hearing loss did not exceed 15 dB for each test tone between 250 Hz and 8000 Hz. As this limit is far below normative threshold values (DIN ISO 7029) we expected to find a large number of otological normal subjects. Using pure-tone audiometry, ABR and noise exposure, we found that 65% of the young male volunteers (mean age 25 years) did not meet the criteria for audiologic normality. The pure-tone thresholds for these subjects were comparable to the expected levels of their fathers' generation.

Adult↗

PubMed1993

[Prevention of vascular complications in endonasal paranasal sinus surgery. I: Anatomic principles and surgical significance].

Anatomic and histologic investigations were performed in 59 cadaver half-heads in order to demonstrate areas of hazard at the posterior skull base during endoscopic surgery and determine morphologic features of surgical relevance. In 78% of the heads the internal carotid artery bulged into the sphenoid sinus from laterally directly behind and beyond the tuberculum for the optic nerve ("anterior bulging"). In 25% of all cases the carotid artery also bulged into the sphenoid sinus from behind ("posterior bulging"). This bulging could amount to as much as 7 mm. Additionally, the thickness of the bony wall at the point of the largest prominence could be very thin (0.1 mm), with 12% of all cases showing bony dehiscences. The width of the posterior ethmoid cells and pneumatization of the paranasal sinuses at this point differed widely, ranging from 8-24 mm. Classification of the carotid loop into five different types demonstrated that the bulgings of the internal carotid artery were larger in more curved types of the artery ("omega" and "U" types) and were smaller in less curved types ("Arkus" and "V" types).

Carotid Artery Injuries↗

PubMed1993

[A new procedure for removal of foreign bodies in the area of the head].

Identification and extraction of penetrating cranial foreign bodies can cause problems in some cases. Small fragments localized deep in the orbit or cerebrum can be especially hard to detect. Severe bleeding and traumatized anatomy can make orientation difficult. We used a new localizing device, computer-assisted surgery (CAS), to good effect in six such cases. CAS is a localizing technique designed to assist the head surgeon during surgery, providing real-time position information. The method is based upon a three-dimensional volume model of the patient's skull generated by preceding computed tomography imaging procedures (CT or MRI). Intraoperative correlation of a 3D-model and the patient's skull allows for real-time position display of a surgical instrument on the monitor screen. Thereby the surgeon is able to localize even small foreign bodies without extensive exploration. In the case of multiple foreign bodies the surgeon calls up a simple documentation facility recording which of the visible fragments have already been extracted. We successfully used the system for extraction of orbital foreign bodies in four and intracerebral foreign bodies in two cases. In a 4-year-old child with gunshot injury the bullet was located in the precentral region and was easily extracted with the CAS system. In a 21-year-old man 39 glass fragments were extracted from the left orbit. In a 36-year-old man a bone fragment was dislocated to the apex of the orbit directly under the optic nerve. Location and extraction were achieved without damage to the orbital structures with the help of the CAS system.

Adult↗