Einfluss der Vakzination von Sauen gegen Mycoplasma hyopneumoniae auf den Impfschutz der Ferkel

Gegenstand und Ziel: Untersuchung der Wirkung der Impfstoffe Stellamune® Mycoplasma (Two-Shot) und Stellamune ® One (One-Shot) (Fa. Pfizer) gegen Mycoplasma hyopneumoniae nach Vakzination von Sauen und/oder Ferkeln. Material und Methoden: 254 Muttersauen und 423 Ferkel wurden fünf Gruppen zugeteilt: Gruppe 1: Sauen vakziniert, Ferkel One-Shot; Gruppe 2: Sauen vakziniert, Ferkel Two-Shot; Gruppe 3: Sauen nicht vakziniert, Ferkel One-Shot; Gruppe 4: Sauen nicht vakziniert, Ferkel Two-Shot; Gruppe 5: Sauen vakziniert, Ferkel nicht vakziniert. Von den Sauen wurde drei Wochen a. p., am Tag der Geburt und drei Wochen p. p. und von den Ferkeln am 1., 21., 63. und 140. Lebenstag Blut entnommen und auf Antikörper gegen M. hyopneumoniae untersucht. Nach der Schlachtung erfolgte eine Lungenbeurteilung. Die täglichen Zunahmen bis zum 105. Lebenstag wurden ermittelt. Ergebnisse: Im Alter von 20 Wochen bestanden keine signifikanten Unterschiede in der humoralen Immunantwort bei den Tieren der Gruppen mit Impfung der Ferkel und die Tiere der nicht vakzinierten Gruppe zeigten signifikant niedrigere Antikörpertiter. Die Probanden aller Gruppen mit einer Saugferkelvakzination hatten signifikant bessere Lungenscores als die Tiere der Gruppe ohne Saugferkelimpfung. Ein signifikanter Unterschied bestand zwischen den Tieren der beiden Gruppen mit einmaliger Impfung der Ferkel, wobei die Tiere der Gruppe ohne Vakzination der Sauen signifikant bessere Lungenscores aufwiesen. Bis zum 105. Lebenstag differierten die täglichen Zunahmen der Tiere der einzelnen Gruppen nicht signifikant. Schlussfolgerungen: Die Antikörpertiter bei den Ferkeln geimpfter und nicht geimpfter Sauen eine Woche p. n. zeigten, dass die Impfung von Sauen geeignet ist, hohe Konzentrationen maternaler Antikörper im Ferkel zu induzieren. Allerdings konnte kein Effekt auf die Tageszunahmen oder den Lungenscore festgestellt werden. In allen Gruppen mit Impfung der Ferkel lag der Lungenscore niedriger als bei der Kontrollgruppe ohne Impfung. Die verschiedenen Impfschemata wirkten sich bis zur Vormast nicht auf das Gewicht der Tiere aus. Klinische Relevanz: In diesem Bestand ließ sich durch die Vakzination der Ferkel mit den eingesetzten Impfstoffen die Lungengesundheit verbessern. Eine alleinige Vakzination der Sauen führte in diesem Versuchsbetrieb zu keinem ausreichenden Schutz.

Intradural-Extramedullary Cavernous Hemangioma of the Left Motor Root C7 - Case Report and Update of the Literature

OBJECTIVE

Intradural-extramedullary cavernomas of the spine are rare lesions with only 21 published cases to date. Due to their rareness and special characteristics diagnosis often is difficult. We report on an additional case of an intradural-extramedullary cavernoma of the spine.

PATIENT

A 56-year-old male presented with left shoulder pain and acute onset of pain affecting the whole spinal column two weeks prior to admission. There were no motor deficits, but a hypesthesia corresponding to the right distal C8-dermatome. MRI revealed an intradural-extramedullary, expansive lesion at the level of C6 with a hyperintense appearance in both T (1)- and T (2)-weighted images. Neither a hemosiderin rim nor contrast enhancement was visible.

RESULTS

During surgery a hematoma and a reddish, berry-like tumor adherent to the left motor root C7 were removed. There were no new neurological deficits, and shoulder and back pain resolved within a few weeks after surgery. Histopathologically a cavernous hemangioma was diagnosed.

CONCLUSIONS

The patient's symptoms were caused both by direct nerve compression and by spinal hemorrhage, most likely spinal SAH. As there was no characteristic hemosiderin rim and due to the hyperintense appearance in T (1)- and T (2)-weighted MR scans, a radiological diagnosis of hemorrhage and classification of the lesion was difficult. Despite their rareness, in patients with signs of spontaneous, spinal SAH and/or nerve compression syndromes cavernous hemangiomas have to be considered as a potential cause.

[Long-term experiences in the therapy of esthesioneuroblastoma]

BACKGROUND

Esthesioneuroblastoma is a rare and clinically variable tumor of nasal sinus and skull base and challenging for modern multidisciplinary therapy. There are no generally known prognostic factors or generally accepted standard therapy regimens.

PATIENTS AND METHODS

Between 1975 and 2001 26 patients were treated after the diagnosis of esthesioneuroblastoma was established. The cases were evaluated retrospectively. According to the classification of Kadish 1 patient (4 %) had stage A, 16 patients (53 %) stage B and 11 cases (43 %) had stage C tumors. Hyams grading could be obtained in 22 cases (81 %). Tumors were in 12 patients (52 %) graded I or II and in 10 cases tumors had grade III or IV (48 %). Operative therapy was performed in 23 patients (88.5 %), being in 5 patients a single mode therapy. In 18 cases combined therapy was performed (surgery and radiotherapy or radiotherapy and chemotherapy).

RESULTS

Actuarial survival was 61.5 % (16/26). Disease specific 10- and 15-year-survival according to the estimation of Kaplan-Meier was 76.2 %. Patients with small tumors (Kadish A/B) had a 15-year-survival of 86.7 % compared to 63.6 % in cases with advanced tumors (Kadish C). In 7 cases (26.9 %) recurrences developed. Salvage therapy was performed in 5 cases (71.4 %) with a success rate and a 15-year survival each of 60 %.

CONCLUSIONS

Therapy of esthesioneuroblastoma is challenging because of rarity and biologic variability of the tumor and and because of lack of a standard therapy. An interdisciplinary multimodal therapeutic approach is necessary especially in case of advanced tumors with promising results. Histopathological grading according to Hyams and tumor stage are important factors for survival and prognosis. Although recurrence can occur with high frequency even after prolonged time interval, long time survival can be improved after aggressive salvage therapy. Therefore longterm follow up is mandatory.

[Renal angiomyolipoma complicated by extension to the renal vein and inferior vena cava]

Renal angiomyolipomas are renal hamartomas. They are usually found incidentally, presenting as well-defined echogenic masses on sonography and fat containing tumors on CT and MRI. We report a case of angiomyolipoma with sonographic and CT evidence of extension to the renal vein and inferior vena cava.

Uterine lipoma: MRI features with pathologic correlation

Fatty tumors of the uterus are rare. Most reported cases have been of the mixed type, consisting of smooth muscle and mature adipose tissue. We present the first case of a pure lipoma with pathologic correlation in which a preoperative diagnosis was made by magnetic resonance imaging.

Delayed Facial Nerve Paresis Following Acoustic Neuroma Resection and Postoperative Vasoactive Treatment

OBJECT

Delayed facial nerve paresis is a well known clinical phenomenon following acoustic neuroma surgery, typically occurring early during the postoperative course. The clinical course of the delayed facial nerve paresis and intraoperative electromyographic (EMG) signals were evaluated in a subgroup of patients who underwent vasoactive treatment for preservation of hearing and developed secondary deterioration after termination of treatment.

METHODS

Between 1990 and 2001 seven patients were identified who received vasoactive treatment for preservation of hearing and developed a delayed facial nerve paresis after termination of medication. Intraoperative facial nerve EMG activity was analyzed in six patients.

RESULTS

All patients developed a delayed facial nerve paresis between 2-5 days following termination of a 10 day treatment consisting of HES and nimodipine. Medication was re-initiated and the facial nerve paresis improved in all patients. In two patients intraoperative EMG signals revealed "A-trains" waveform patterns, which are highly suggestive for an immediate postoperative facial nerve paresis, whereas in four patients no pathognomonic EMG patterns could be recorded.

CONCLUSIONS

The delayed onset of a facial paresis following termination of vasoactive treatment points to a disturbed microcirculation of the nerve as the main pathophysiological feature. Two groups could be identified on the basis of intraoperative EMG activity. In one group with presence of "A-trains" medication apparently masked the onset of an immediate postoperative facial nerve deficit. Four patients without "A-trains" did not develop a typical delayed facial nerve paresis during vasoactive treatment, but thereafter. The time lag between termination of treatment and onset of a delayed palsy points to a protective effect due to improved microcirculation.

[Multidetector CT and MRI in pancreatic diseases]

Multidetector CT and MRI are the most efficient non invasive techniques in the assessment of pancreatic diseases. As with MRI, multidetector CT has now become an all in one examination using 2 D and 3 D multiplanar reformations with the ability to perform with high accuracy: a) vascular assessment using MIP reconstruction and b) biliary and pancreatic ducts assessment using minIP reconstruction. This review compares and illustrates the respective advantages of MRI and multidetector CT in the assessment of pancreatic diseases.

Localisation of the sensorimotor cortex during surgery for brain tumours: feasibility and waveform patterns of somatosensory evoked potentials

OBJECTIVE

Intraoperative localisation of the sensorimotor cortex using the phase reversal of somatosensory evoked potentials (SEPs) is an essential tool for surgery in and around the perirolandic gyri, but unsuccessful and perplexing results have been reported. This study examines the effect of tumour masses on the waveform characteristics and feasibility of SEP compared with functional neuronavigation and electrical motor cortex mapping.

METHODS

In 230 patients with tumours of the sensorimotor region the SEP phase reversal of N20-P20 was recorded from the exposed cortex using a subdural grid or strip electrode. In one subgroup of 80 patients functional neuronavigation was performed with motor and sensory magnetic source imaging and in one subgroup of 40 patients the motor cortex hand area was localised by electrical stimulation mapping.

RESULTS

The intraoperative SEP method was successful in 92% of all patients, it could be shown that the success rate rather depended on the location of the lesion than on preoperative neurological deficits. In 13% of the patients with postcentral tumours no N20-P20 phase reversal was recorded but characteristic polyphasic and high amplitude waves at 25 ms and later made the identification of the postcentral gyrus possible nevertheless. Electrical mapping of the motor cortex took up to 30 minutes until a clear result was obtained. It was successful in 37 patients, but failed in three patients with precentral and central lesions. Functional neuronavigation indicating the tumour margins and the motor and sensory evoked fields was possible in all patients.

CONCLUSION

The SEP phase reversal of N20-P20 is a simple and reliable technique, but the success rate is much lower in large central and postcentral tumours. With the use of polyphasic late waveforms the sensorimotor cortex may be localised. By contrast with motor electrical mapping it is less time consuming. Functional neuronavigation is a desirable tool for both preoperative surgical planning and intraoperative use during surgery on perirolandic tumours, but compensation for brain shift, accuracy, and cost effectiveness are still a matter for discussion.

[Imaging of the anterior abdominal wall: ultrasonography and CT features]

US and CT have both become major tools in imaging of the anterior abdominal wall. The goal of this pictorial review is to illustrate the respective roles of US and CT in the evaluation of normal and abnormal anterior abdominal wall.

Vasoactive treatment for hearing preservation in acoustic neuroma surgery

OBJECT

Delayed hearing loss following surgery for acoustic neuroma indicates anatomical and functional preservation of the cochlear nerve and implies that a pathophysiological mechanism is initiated during surgery and continues thereafter. Intraoperative brainstem auditory evoked potentials (BAEPs) typically demonstrate gradual reversible loss of components in these patients.

METHODS

Based on this BAEP pattern, a consecutive series of 41 patients with unilateral acoustic neuromas was recruited into a prospective randomized study to investigate hearing outcomes following the natural postoperative course and recuperation after vasoactive medication. Both groups were comparable in patient age, tumor size, and preoperative hearing level. Twenty patients did not receive postoperative medical treatment. In 70% of these patients anacusis was documented and in 30% hearing was preserved. Twenty-one patients were treated with hydroxyethyl starch and nimodipine for an average of 9 days. In 66.6% of these patients hearing was preserved and in 33.3% anacusis occurred.

CONCLUSIONS

These results are statistically significant (p < 0.05, chi2 = 5.51) and provide evidence that these surgically treated patients suffer from a disturbed microcirculation that causes delayed hearing loss following removal of acoustic neuromas.

Clinical and neurophysiological observations after superior petrosal vein obstruction during surgery of the cerebellopontine angle: case report

IMPORTANCE

Preservation of venous drainage during surgery of the cerebellopontine angle has received little attention.

CLINICAL PRESENTATION

We describe changes in brainstem auditory evoked potentials after temporary obstruction of the superior petrosal vein during surgical resection of a small meningioma at the petrous apex via a standard suboccipital-lateral approach. Temporary clipping of the petrosal vein resulted in deterioration of the brainstem auditory evoked potentials. The tumor was removed with preservation of the superior petrosal vein.

CONCLUSION

A transient postoperative cochlear nerve deficit emphasizes the importance of venous drainage and its preservation during surgery for small lesions of the cerebellopontine angle that do not distort normal anatomic structures.

Prospects for ab initio protein structural genomics

We present the results of a large-scale testing of the ROSETTA method for ab initio protein structure prediction. Models were generated for two independently generated lists of small proteins (up to 150 amino acid residues), and the results were evaluated using traditional rmsd based measures and a novel measure based on the structure-based comparison of the models to the structures in the PDB using DALI. For 111 of 136 all alpha and alpha/beta proteins 50 to 150 residues in length, the method produced at least one model within 7 A rmsd of the native structure in 1000 attempts. For 60 of these proteins, the closest structure match in the PDB to at least one of the ten most frequently generated conformations was found to be structurally related (four standard deviations above background) to the native protein. These results suggest that ab initio structure prediction approaches may soon be useful for generating low resolution models and identifying distantly related proteins with similar structures and perhaps functions for these classes of proteins on the genome scale.

Ligation-mediated suppression-PCR as a powerful tool to analyse nuclear gene sequences in the green alga Chlamydomonas reinhardtii

To improve the analysis of unknown flanking DNA sequences adjacent to known sequences in nuclear genomes of photoautotrophic eukaryotic organisms, we established the technique of ligation-mediated suppression-PCR (LMS-PCR) in the green alga Chlamydomonas reinhardtii for (1) walking from a specific nuclear insertion fragment of random knockout mutants into the unknown flanking DNA sequence to identify and analyse disrupted genomic DNA regions and for (2) walking from highly conserved DNA regions derived from known gene iso-forms into flanking DNA sequences to identify new members of protein families. The feasibility of LMS-PCR for these applications was successfully demonstrated in two different approaches. The first resulted in the identification of a genomic DNA fragment flanking a nuclear insertion vector in a random knockout mutant whose phenotype was characterised by its inability to perform functional LHC state transitions. The second approach targeted the cab gene family. An oligonucleotide of a cabII gene, derived from a highly conserved region, was used to identify potential cab gene regions in the nuclear genome of Chlamydomonas. LMS-PCR combined with 3' rapid amplification of cDNA ends (3' RACE) and a PCR-based screening of a cDNA library resulted in the identification of the new cabII gene lhcb4. Both results clearly indicate that LMS-PCR is a powerful tool for the identification of flanking DNA sequences in the nuclear genome of Chlamydomonas reinhardtii.

[Langerhans-cell histiocytosis of the orbit; diagnosis, treatment and outcome in three patients -- children and adults]

BACKGROUND

Langerhans cell histiocytosis usually affects children. Systemic Langerhans cell histiocytosis may be present in 37% of affected children. Ten per cent of all children die of the disease.

CASE REPORTS

Patient 1. A 9-year-old boy presented with painful upper lid swelling OD. Ultrasonography revealed a space-occupying lesion adjacent to a lytic defect of the frontal bone as shown on coronal CT. MRI showed marked contrast enhancement of the mass which came close to the intracranial fossa. The vascularized tumor was excised using an anterior orbitotomy with upper lid crease incision. No evidence of local or systemic recurrence was present three years postoperatively. Patient 2. A 19-year-old male presented with foreign body sensation, double vision OS and numbness of the left face of six weeks' duration. The ocular findings revealed a sixth nerve palsy OS. Otherwise, the eyes were unremarkable. Sensitivity of cranial nerve V2 was decreased. CT revealed an osteolytic process in the lateral orbital wall and sphenoid wing. MRI demonstrated a space-occupying lesion involving the temporalis muscle laterally, the pterygopalatine fossa medially with intracranial extension into the temporal lobe. Surgical excision was performed using a transcranial approach. Signs and symptoms had completely resolved six months after surgery with no evidence of local or systemic recurrence. Patient 3. A 30-year-old male presented with right-sided headache, painful upper lid swelling and vertical diplopia. Coronal CT scan revealed a lytic defect in the frontal bone laterally. Curettage and complete excision were performed using an infrabrow incision. Follow-up examination four years later revealed an intact ocular motility with no evidence of local or systemic recurrence. In all three cases the tumor showed characteristic light-microscopy and immunohistochemical features of Langerhans cell histiocytosis.

CONCLUSION

Langerhans cell histiocytosis of the orbit is an important differential diagnosis of osteolytic and/or space-occupying lesions not only in children, but also in adults. A diagnostic biopsy followed by surgical excision and/or local and systemic corticoid- and chemotherapy are essential regarding the prognosis of local and systemic disease.

Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case

Contralateral hearing loss after surgical procedures within the cerebellopontine angle is rarely seen and its pathophysiological background is not yet understood. A patient with contralateral hearing loss after microvascular decompression for trigeminal neuralgia is described. Ipsilateral brainstem auditory potential (BAEP) monitoring and facial nerve EMG did not show major abnormalities. During otherwise uneventful and successful surgery a branch of the petrosal vein was sacrificed to widen the access to the trigeminal root exit zone. On the third postoperative day the patient complained about contralateral hearing loss, which was verified by audiometry. Contralateral BAEPs showed low amplitudes and delayed interpeak latencies. Brain CT was normal. Brain MRI on the 8th postoperative day disclosed abnormal signals within the ipsilateral inferior colliculus. Intravenous heparinisation was performed and hearing slowly recovered over a 3 month period. Results from this patient offer a pathophysiological mechanism for contralateral hearing loss after cerebellopontine angle surgery, illustrate the importance of venous drainage preservation, gives evidence about the generation of BAEP components within the contralateral brainstem, and stresses the importance of intraoperative BAEP monitoring.

Continuous electromyography monitoring of motor cranial nerves during cerebellopontine angle surgery

OBJECT

Electromyography (EMG) monitoring is expected to reduce the incidence of motor cranial nerve deficits in cerebellopontine angle surgery. The aim of this study was to provide a detailed analysis of intraoperative EMG phenomena with respect to their surgical significance.

METHODS

Using a system that continuously records facial and lower cranial nerve EMG signals during the entire operative procedure, the authors examined 30 patients undergoing surgery on acoustic neuroma (24 patients) or meningioma (six patients). Free-running EMG signals were recorded from muscles targeted by the facial, trigeminal, and lower cranial nerves, and were analyzed off-line with respect to waveform characteristics, frequencies, and amplitudes. Intraoperative measurements were correlated with typical surgical maneuvers and postoperative outcomes. Characteristic EMG discharges were obtained: spikes and bursts were recorded immediately following the direct manipulation of a dissecting instrument near the cranial nerve, but also during periods when the nerve had not yet been exposed. Bursts could be precisely attributed to contact activity. Three distinct types of trains were identified: A, B, and C trains. Whereas B and C trains are irrelevant with respect to postoperative outcome, the A train--a sinusoidal, symmetrical sequence of high-frequency and low-amplitude signals--was observed in 19 patients and could be well correlated with additional postoperative facial nerve paresis (in 18 patients).

CONCLUSIONS

It could be demonstrated that the occurrence of A trains is a highly reliable predictor for postoperative facial palsy. Although some degree of functional worsening is to be expected postoperatively, there is a good chance of avoiding major deficits by warning the surgeon early. Continuous EMG monitoring is superior to electrical nerve stimulation or acoustic loudspeaker monitoring alone. The detailed analysis of EMG-waveform characteristics is able to provide more accurate warning criteria during surgery.

[Detection of asymptomatic venous thrombosis after lower limb prosthetic surgery. Retrospective evaluation of a systematic approach using Doppler ultrasonography: 400 cases]

OBJECTIVES

The purpose of this study was to evaluate a pragmatic approach using duplex ultrasonography (US) for detecting deep vein thrombosis (DVT) after total hip (THA) and total knee (TKA) replacement.

METHODS

Venous B-mode and color duplex US examination of both legs including a systematic evaluation of calf veins was performed twice during hospital stay (Between day 1 and day 4 for the first exam and between day 7 and day 11 for the second) in 400 consecutive patients.

RESULTS

Deep vein thrombosis was diagnosed in 53 patients (13.5%) including 7 patients with proximal DVT. Thrombosis was asymptomatic in 46 patients (85%), and was bilateral or concerned the non-operated leg in 8 patients (14.5%). No clinical pulmonary embolism (PE) occurred during hospital stay (mean hospital stay: 12.3). Prior phlebitis and age over 70 were identified as a statistically significant risk-factor for post-operative DVT (p = 0.001 and p < 0.01 respectively) concerning the whole series and the THA series (p < 0.02 and p < 0.04 respectively). No statistically significant risk factor was founded for the TKA series (p < 0.2 and p < 0.2 respectively). All patients were seen at three months. Four patients (1.16%) developed DVT between hospital discharge and the 3-month follow-up visit. One patient with coronary disease died suddenly on post-operative day 24, without clinical signs or symptoms of PE or DVT.

CONCLUSION

Venous US performed twice after total hip replacement detected asymptomatic DVT in 85% of patients. This approach might explain the absence of PE in our series and thus justify systematic ultrasonographic evaluation of lower limb veins after prosthetic replacement.

The prognostic value of intraoperative BAEP patterns in acoustic neurinoma surgery

Based on a consecutive series of 70 hearing patients with unilateral acoustic neurinomas and intraoperative monitoring of brain-stem auditory evoked potentials (BAEP), 4 dynamic BAEP patterns could be characterized. These patterns correspond with early and late postoperative hearing outcome. All patients with stable wave V (pattern 1) showed definite hearing preservation, all patients with irreversible abrupt loss of BAEP (pattern 2) lost their hearing, despite early hearing preservation in two cases. All patients with irreversible progressive loss of either wave I or wave V (pattern 3) eventually suffered from definite postoperative hearing loss, despite early hearing preservation in two cases. Those cases with intraoperative reversible loss of BAEP (pattern 4) showed variable short and long term hearing outcome. In 34% hearing was preserved, 44% suffered from postoperative hearing loss, the remaining 22% showed postoperative hearing fluctuation, either as a delayed hearing loss or as reversible hearing loss. Postoperative hearing fluctuation indicates anatomical and functional preservation of the cochlear nerve during surgery and is suggestive of a pathophysiological mechanism initiated during the surgical procedure and continuing thereafter. Patients at risk for delayed hearing loss can be identified during surgery by a characteristic BAEP pattern and may benefit from vasoactive treatment.

Pericollicular approaches to the rhomboid fossa. Part II. Neurophysiological basis

OBJECT

The authors describe their technique of electrophysiological mapping to assist pericollicular approaches into the rhomboid fossa.

METHODS

Surgical approaches to the rhomboid fossa can be optimized by direct electrical stimulation of superficially located nuclei and fibers. Electrophysiological mapping allows identification of facial nerve fibers, nuclei of the abducent and hypoglossal nerves, motor nucleus of the trigeminal nerve, and the ambiguous nucleus. Stimulation at the surface of the rhomboid fossa performed using the threshold technique allows localization above the area that is located closest to the surface. Simultaneous bilateral electromyographic (EMG) recordings from cranial motor nerves obtained during stimulation document the selectivity of evoked EMG responses. With respect to stimulation parameters and based on morphometric measurements, the site of stimulation can be assumed to be the postsynaptic fibers at the axonal cone. Strict limitation to 10 Hz with a maximum stimulation intensity not exceeding 2 mA can be considered safe. Direct side effects of electrical stimulation were not observed.

CONCLUSIONS

Electrical stimulation based on morphometric data obtained on superficial brainstem anatomy defines two safe paramedian supra- and infracollicular approaches to the rhomboid fossa and is particularly helpful in treating intrinsic brainstem lesions that displace normal anatomical structures.

Preservation of hearing in large acoustic neurinomas following removal via suboccipito-lateral approach

A consecutive series of 61 patients with pre-operative hearing underwent surgical removal of a large acoustic neurinoma via the lateral suboccipital approach between 1984 and 1996. Brain-stem auditory evoked potentials (BAEP) were present in all cases before surgery and all patients underwent intra-operative monitoring of BAEP. The average tumour size including the portion within the meatus acusticus internus was 30, 5 mm (range 20 mm-49 mm). Complete tumour removal was achieved in all but three cases. In 43.1% of patients with complete tumour removal hearing was preserved initially after surgery. Delayed postoperative hearing loss was observed in 11 patients and hearing recovery in 2 patients leading to 27.5% definite hearing preservation. Hearing preservation was achieved in 37% of cases with tumour size between 20 mm-29 mm and in 23.5% of case with tumour size larger than 30 mm. These results indicate that even in large neurinoms hearing preservation should be attempted in all patients with documented pre-operative hearing and BAEP.

The brave new world of quantum health care: some thoughts on the anatomy and physiology of a medical entity and the culture in which it is immersed. Part I

In the absence of government intervention, the marketplace has taken over control of the health care sector in response to double-digit cost inflation. In the process, physician autonomy has waned. Health decisions are often made by corporate administrators; secretly hidden, less trained health personnel, and rigid protocols. Physician response as a profession has included dismay, anxiety, and depression. To return health care decisions back to physicians and to enhance the doctor/patient relationship, two suggestions are made. The first is the development of a task-oriented structure, energized by an implementation mechanism and information technology. This will allow for state-of-the-art, effective use of resources with care then judged by service, not by cost or access. The second is an introspective assessment of the physician's own personal psyche and the mission of the Profession. Redefining the mission and the motives behind it will allow the physician to "heal thyself" and move on to better and more satisfying patient care. The social contract with the Profession will then likely be reaffirmed, reestablished, and strengthened.

Pericollicular surgical approaches to the rhomboid fossa. Part I. Anatomical basis

A safe paramedian approach to the rhomboid fossa for surgical treatment of intrinsic brainstem lesions is based on detailed knowledge of the morphometric anatomy of superficially located motor structures. The morphometry of the rhomboid fossa is described in this report on the basis of histological studies conducted in six human brainstem specimens, with special emphasis on the colliculus facialis and the trigona nervi hypoglossi and vagi. Morphometric data include analysis of shrinkage factors in each specimen. The colliculus is a landmark for the nervus facialis, oculomotor nuclei, and the paramedian pontine reticular formation. In the surgeon's view from the posterior approach, the colliculus covers an area of 5.7 mm in the mediolateral and 6.8 mm in the craniocaudal direction and is located 0.6 mm lateral to the median sulcus. The fibers of the nervus facialis come as close as 0.2 mm to the surface of the fourth ventricle. The colliculus is located 15.7 mm above the obex. The trigona nervi hypoglossi and vagi cover a rectangular area measuring 3.1 by 6.5 mm and serve as a landmark for lower cranial nerve nuclei. These nuclei are located 0.3 mm lateral to the midline. An area with a maximum extension of 0.9 cm between the colliculus and trigona can be used for an infracollicular paramedian approach. The same applies to a supracollicular approach cranial to the colliculus and caudal to the fibers of the nervus trochlearis within the medullary velum, with a craniocaudal extension of 4 mm. Superficial motor nuclei and fibers can be identified by neurophysiological mapping, which helps to define safe surgical corridors into the rhomboid fossa, thus reducing functional morbidity caused by the operative approach in intrinsic pontine and pontomedullary lesions.

Magnetic source imaging combined with image-guided frameless stereotaxy: a new method in surgery around the motor strip

OBJECTIVE

In this study, information about the localization of the central sulcus obtained by magnetic source imaging (MSI) was intraoperatively translated to the brain, using frameless image-guided stereotaxy. In the past, the MSI results could be translated to the surgical space only by indirect methods (e.g., the comparison of the MSI results, displayed in surface renderings, with bony landmarks or blood vessels on the exposed brain surface).

METHODS

Somatosensory evoked fields were recorded with a MAGNES II biomagnetometer (Biomagnetic Technologies Inc., San Diego, CA). Using the single equivalent current dipole model, the localization of the somatosensory cortex was superimposed on magnetic resonance imaging with a self-developed contour fit program. The magnetic resonance image set containing the magnetoencephalographic dipole was then transferred to a frameless image-guided stereotactic system. Intraoperatively, the gyrus containing the dipole was identified as the postcentral gyrus, using neuronavigation, and the next anterior sulcus was regarded as the central sulcus. With intraoperative cortical recording of somatosensory evoked potentials, this assumption was verified in each case.

RESULTS

In all cases, the preoperatively assumed localization of the central sulcus and motor cortex with MSI agreed with the intraoperative identification of the central sulcus using the phase reversal technique.

CONCLUSION

The combined use of MSI and a frameless stereotactic system allows a fast orientation of eloquent brain areas during surgery. This may contribute to a safer and more radical surgery in lesions adjacent to the motor cortex.

[Cavo-mesenterico-portal shunt in inferior vena cava obstruction]

We report a case of cavo-mesenterico-portal shunt in vena cava obstruction. The main role and frequency of this preferential pathway are reviewed and analyzed.

[Renal varices. X-ray computed tomographic diagnosis and treatment by embolization]

Two cases of recurrent macroscopic hematuria in which the diagnosis of left renal vein varices has suggested on CT are described. Bloody efflux was seen from the left ureteric orifice. On CT scans, tubulated contrast-enhanced densities in left perineal fat were seen. Selective renal angiography was normal. Selective left renal phlebography demonstrated intra and perirenal varices. In the two cases, embolization with metallic coli was successfully performed during left renal phlebography, to stop renal varices flux. Diagnostic and therapeutic modalities of renal varices are discussed with predominant place for CT and phlebography.

Anatomical aspects for surgery within the floor of the IVth ventricle

Successful removal of brainstem lesions is among other factors dependent on a safe surgical approach into the brainstem avoiding functional morbidity of superficially located nervous structures. Most midline pontine and pontomedullary lesions can be reached via a transvermian approach through the rhomboid fossa. This review describes the anatomical basis for the pericollicular paramedian surgical approaches into the rhomboid fossa with special emphasis on the microscopic anatomy.

On the site of transcranial magnetic stimulation of the facial nerve: electrophysiological observations in two patients after transection of the facial nerve during neuroma removal

The site of stimulation of the facial nerve after transcranial temporo-occipital magnetic stimulation is being controversially discussed, particularly whether the nerve is stimulated in the root exit zone in the cerebellopontine angle or whether stimulation originates within the bony canal of the facial nerve. In two case reports, the neurophysiological findings after the surgical transection of the facial nerve during the extirpation of a large acoustic and a facial nerve neuroma are presented. In both cases, transcranial magnetic stimulation of the facial nerve produced compound muscle action potential 4 and 2 days after the dissection of the facial nerve at the internal auditory canal and in the supralabyrinthine portion. These findings indicate that the site of stimulation in transcranial magnetic stimulation can be located to the course of the facial nerve within its bony petrosal canal distal to the external genu.

Intraoperative identification of motor areas of the rhomboid fossa using direct stimulation

Intraoperative electrical identification of motor areas within the floor of the fourth ventricle was successfully carried out in a series of 10 patients with intrinsic pontine lesions and lesions infiltrating the brain stem. Direct electrical stimulation was used to identify the facial colliculus and the hypoglossal triangle before the brain stem was entered. Multichannel electromyographic recordings documented selective stimulation effects. The surgical approach to the brain stem was varied according to the electrical localization of these structures. During removal of the lesion, functional integrity was monitored by intermittent stimulation. In lesions infiltrating the floor of the fourth ventricle, stimulation facilitated complete removal. Permanent postoperative morbidity of facial or hypoglossal nerve dysfunction was not observed. Mapping of the floor of the fourth ventricle identifies important surface structures and offers a safe corridor through intact nervous structures during surgery of brain-stem lesions. Reliable identification is particularly important in mass lesions with displacement of normal topographical anatomy.