Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

Outcomes of COVID-19 With the Mayo Clinic Model of Care and Research

OBJECTIVE

To report the Mayo Clinic experience with coronavirus disease 2019 (COVID-19) related to patient outcomes.

METHODS

We conducted a retrospective chart review of patients with COVID-19 diagnosed between March 1, 2020, and July 31, 2020, at any of the Mayo Clinic sites. We abstracted pertinent comorbid conditions such as age, sex, body mass index, Charlson Comorbidity Index variables, and treatments received. Factors associated with hospitalization and mortality were assessed in univariate and multivariate models.

RESULTS

A total of 7891 patients with confirmed COVID-19 infection with research authorization on file received care across the Mayo Clinic sites during the study period. Of these, 7217 patients were adults 18 years or older who were analyzed further. A total of 897 (11.4%) patients required hospitalization, and 354 (4.9%) received care in the intensive care unit (ICU). All hospitalized patients were reviewed by a COVID-19 Treatment Review Panel, and 77.5% (695 of 897) of inpatients received a COVID-19-directed therapy. Overall mortality was 1.2% (94 of 7891), with 7.1% (64 of 897) mortality in hospitalized patients and 11.3% (40 of 354) in patients requiring ICU care.

CONCLUSION

Mayo Clinic outcomes of patients with COVID-19 infection in the ICU, hospital, and community compare favorably with those reported nationally. This likely reflects the impact of interprofessional multidisciplinary team evaluation, effective leveraging of clinical trials and available treatments, deployment of remote monitoring tools, and maintenance of adequate operating capacity to not require surge adjustments. These best practices can help guide other health care systems with the continuing response to the COVID-19 pandemic.

Effectiveness of hands-on tutoring and guided self-directed learning versus self-directed learning alone to educate critical care fellows on mechanical ventilation - a pilot project

BACKGROUND

Physicians require extensive training to achieve proficiency in mechanical ventilator (MV) management of the critically ill patients. Guided self-directed learning (GSDL) is usually the method used to learn. However, it is unclear if this is the most proficient approach to teaching mechanical ventilation to critical care fellows. We, therefore, investigated whether critical care fellows achieve higher scores on standardized testing and report higher satisfaction after participating in a hands-on tutorial combined with GSDL compared to self-directed learning alone.

METHODS

First-year Pulmonary and Critical Care Medicine (PCCM) fellows (n=6) and Critical Care Internal Medicine (CCIM) (n=8) fellows participated. Satisfaction was assessed using the Likert scale. MV knowledge assessment was performed by administering a standardized 25-question multiple choice pre- and posttest. For 2 weeks the CCIM fellows were exposed to GSDL, while the PCCM fellows received hands-on tutoring combined with GSDL.

RESULTS

Ninety-three percentage (6 PCCM and 7 CCIM fellows, total of 13 fellows) completed all evaluations and were included in the final analysis. CCIM and PCCM fellows scored similarly in the pretest (64% vs. 52%, p=0.13). Following interventions, the posttest scores increased in both groups. However, no significant difference was observed based on the interventions (74% vs. 77%, p=0.39). The absolute improvement with the hands-on-tutoring and GSDL group was higher than GSDL alone (25% vs. 10%, p=0.07). Improved satisfaction scores were noted with hands-on tutoring.

CONCLUSIONS

Hands-on tutoring combined with GSDL and GSDL alone were both associated with an improvement in posttest scores. Absolute improvement in test and satisfaction scores both trended higher in the hands-on tutorial group combined with GSDL group.

Mechanosensitive ion channel Piezo2 is important for enterochromaffin cell response to mechanical forces

KEY POINTS

The gastrointestinal epithelial enterochromaffin (EC) cell synthesizes the vast majority of the body's serotonin. As a specialized mechanosensor, the EC cell releases this serotonin in response to mechanical forces. However, the molecular mechanism of EC cell mechanotransduction is unknown. In the present study, we show, for the first time, that the mechanosensitive ion channel Piezo2 is specifically expressed by the human and mouse EC cells. Activation of Piezo2 by mechanical forces results in a characteristic ionic current, the release of serotonin and stimulation of gastrointestinal secretion. Piezo2 inhibition by drugs or molecular knockdown decreases mechanosensitive currents, serotonin release and downstream physiological effects. The results of the present study suggest that the mechanosensitive ion channel Piezo2 is specifically expressed by the EC cells of the human and mouse small bowel and that it is important for EC cell mechanotransduction.

ABSTRACT

The enterochromaffin (EC) cell in the gastrointestinal (GI) epithelium is the source of nearly all systemic serotonin (5-hydroxytryptamine; 5-HT), which is an important neurotransmitter and endocrine, autocrine and paracrine hormone. The EC cell is a specialized mechanosensor, and it is well known that it releases 5-HT in response to mechanical forces. However, the EC cell mechanotransduction mechanism is unknown. The present study aimed to determine whether Piezo2 is involved in EC cell mechanosensation. Piezo2 mRNA was expressed in human jejunum and mouse mucosa from all segments of the small bowel. Piezo2 immunoreactivity localized specifically within EC cells of human and mouse small bowel epithelium. The EC cell model released 5-HT in response to stretch, and had Piezo2 mRNA and protein, as well as a mechanically-sensitive inward non-selective cation current characteristic of Piezo2. Both inward currents and 5-HT release were inhibited by Piezo2 small interfering RNA and antagonists (Gd³⁺ and D-GsMTx4). Jejunum mucosal pressure increased 5-HT release and short-circuit current via submucosal 5-HT3 and 5-HT4 receptors. Pressure-induced secretion was inhibited by the mechanosensitive ion channel antagonists gadolinium, ruthenium red and D-GsMTx4. We conclude that the EC cells in the human and mouse small bowel GI epithelium selectively express the mechanosensitive ion channel Piezo2, and also that activation of Piezo2 by force leads to inward currents, 5-HT release and an increase in mucosal secretion. Therefore, Piezo2 is critical to EC cell mechanosensitivity and downstream physiological effects.

Angiotensin II stimulates nitric oxide production in pulmonary artery endothelium via the type 2 receptor

We previously reported that angiotensin II stimulates an increase in nitric oxide production in pulmonary artery endothelial cells. The aims of this study were to determine which receptor subtype mediates the angiotensin II-dependent increase in nitric oxide production and to investigate the roles of the angiotensin type 1 and type 2 receptors in modulating angiotensin II-dependent vasoconstriction in pulmonary arteries. Pulmonary artery endothelial cells express both angiotensin II type 1 and type 2 receptors as assessed by RT-PCR, Western blot analysis, and flow cytometry. Treatment of the endothelial cells with PD-123319, a type 2 receptor antagonist, prevented the angiotensin II-dependent increase in nitric oxide synthase mRNA, protein levels, and nitric oxide production. In contrast, the type 1 receptor antagonist losartan enhanced nitric oxide synthase mRNA levels, protein expression, and nitric oxide production. Pretreatment of the endothelial cells with either PD-123319 or an anti-angiotensin II antibody prevented this losartan enhancement of nitric oxide production. Angiotensin II-dependent enhanced hypoxic contractions in pulmonary arteries were blocked by the type 1 receptor antagonist candesartan; however, PD-123319 enhanced hypoxic contractions in angiotensin II-treated endothelium-intact vessels. These data demonstrate that angiotensin II stimulates an increase in nitric oxide synthase mRNA, protein expression, and nitric oxide production via the type 2 receptor, whereas signaling via the type 1 receptor negatively regulates nitric oxide production in the pulmonary endothelium. This endothelial, type 2 receptor-dependent increase in nitric oxide may serve to counterbalance the angiotensin II-dependent vasoconstriction in smooth muscle cells, ultimately regulating pulmonary vascular tone.

Recurrent arachnoid cyst of Meckel's cave mimicking a brain stem ischaemia. Report of a rare case

A 44-years old man developed TIA-like symptoms with dysaesthesia around the mouth, vertigo and diplopia. MRI revealed a cystic space-occupying lesion on the right Meckel's cave, which spread out into cerebellopontine angle in a further examination. Therefore surgical exploration was performed using a suboccipital approach. An arachnoidal cyst was found and removed including its wall. About three months later the patient suffered again from dysaesthesias of the right side of the face and a new MRI revealed a recurrence of the lesion, with extension into the cerebellopontine angle, too. Surgical revision was done using the same approach and the recurrent cyst was removed. Postoperatively, there were a transient hypaesthesia in the distribution area of the right trigeminal nerve and a light pulmonary embolism occurred as a complication. No symptoms have returned during an observation period of 15 months.

CONCLUSION

An arachnoidal cyst must be considered as a rare cause, when a lesion is found at the Meckel's cave with intermittent clinical symptoms of a trigeminal nerve affection. As surgical treatment we favour fenestration and cyst wall resection.

The role of endothelins in the regulation of pituitary function

The different members of the endothelin peptide family exhibit potent, long-lasting vasoconstrictive effects and thus play a central role in blood pressure regulation. However, endothelins have also been shown to modulate renal, cardiac and immune functions under physiological and pathophysiological conditions. In addition, endothelins are thought to be involved in the progression of some types of tumours. Soon after their discovery in 1988, it was shown that endothelins affect hormone release in the pituitary. Moreover, the intrapituitary production and expression of both endothelins and endothelin receptors have been described. This review summarises the present day knowledge concerning the expression and regulation of intrapituitary endothelins and their receptors. In addition, the effects of endothelins on hormone production by anterior, intermediate and posterior pituitary cell types are reviewed and their importance for pituitary physiology and pathophysiology is discussed.

Anterior cervical spine fusion using RABEA-Titan-Cages avoiding iliac crest spongiosa: first experiences and results

INTRODUCTION

In cervical discectomy using the ventral approach both, the necessity of replacement of the removed disc space itself as well as the material of the graft, if used, is still a matter of discussion. New approaches are titan-cages, usually filled with autologeous spongiosa. We present in the following study our first experiences using the hollow RABEA-Titan-Cages without filling with spongiosa to avoid the iliac crest complications.

MATERIAL AND METHODS

63 patients (33 male, 30 female, age 25-79 years, mean 52 years) were operated on a degenerative cervical disc herniation by ventral discectomy and replacement of the disc by the cage for fusion. The mean follow-up was 8 months. The preoperative symptoms were radiculopathies (n = 43) and myelopathies (n = 20). The diagnosis was confirmed by CT, MRI, myelography/CT and functional plain x-ray examination excluding instability. Level of the disc herniation: C3/4 n = 3, C4/5 n = 4, C5/6 n = 21, C6/7 n = 23, C7/Th1 n = 5, and 7 cases with 2 levels. In 30 cases we found hard discs, in 13 cases soft discs and in 20 patients combined lesions. All patients were intra- and postoperatively controlled by x-ray examination.

RESULTS

Free of complaints were 17 patients, a marked improvement was found in 33 cases, a minor improvement in 10 cases, from those 4 patients additionally suffered from depression or alcoholism and 1 patient had a trauma in the history. 3 patients showed no change. Minor neck pain was reported in 5 cases. The mean postoperative hospitalisation was 8 days. Surgery related complications: temporary radicular palsies n = 5, hoarseness/problems with swallowing n = 5. In 2 cases (3%) with osteoporosis surgical revision of the cage was necessary (one case with ventral dislocation and one case with recurrent nerve root compression). In all other cases the x-ray control proved the correct placement of the cages intra- and postoperatively on discharge.

CONCLUSION

For the anterior cervical fusion, the hollow RABEA-Titan-Cages present good clinical results and help to avoid complications from the iliac crest donor site. For long-term results, a longer follow-up and a increased number of patients is required.

Cerebellopontine angle meningiomas (cpam)--clinical characteristics and surgical results

INTRODUCTION

About 10% of the tumourous lesions in the cerebellopontine angle are meningiomas according to the literature. Evidently, these tumours differ from the other lesions by their clinical presentation as well as by the surgical results, which will be presented in the following article.

PATIENT MATERIAL

We report on 26 patients (22 females, 4 males: age distribution 45-81 years, mean 63 years) operated on CPAM's in the last 8 years. Clinical history lasted from 2 weeks to 9 years (mean 17 months). Cerebellar symptoms were the most frequent findings (n = 22), followed by cranial nerve (V, VII, and VIII) deficits (n = 12) and signs of increased intracranial pressure (n = 7). In 3 clinically asymptomatic cases the lesion was found incidentally, and there was 1 patient with a recurrent lesion. The radiological procedures included CT-scan in 17 patients, MR-imaging in 18, MR-angiography in 2 cases and angiography in 2 cases. Hydrocephalus was demonstrated in 8 cases. Tumour size ranged from 2.8 to 7 cm (mean 4.2 cm). All patients underwent osteoclastic craniotomy with complete tumour removal. Temporary CSF-drainage was necessary in 8 cases, monitoring was done in 9 patients.

RESULTS

Postoperative follow-up period ranged from 3 months to 5 years (mean 2.5 years). After 1 month, 14 patients were discharged home and 12 were transferred into other hospitals in good condition. Improvement was achieved in 19 cases, 5 patients were equal to their preoperative situation, in one case a temporary deterioration with tetraparesis and in 1 case deterioration of hearing was found. After an average follow-up of 2.5 years, 22 patients were self-sufficient without or with minimal neurological deficits at home, 2 were moderately disabled and 2 died in the meantime due to other diseases. Among the operative complications, we observed 3 CSF-fistulas, 1 requiring surgical reexploration as well as 1 rebleeding and additionally 1 meningitis. Non-surgical complications were found in 5 patients.

CONCLUSIONS

Cerebellar ataxia and impairment of hearing are the clinical leading symptoms of CPAM's. At diagnosis, these tumours are impressively large, but the operative results are very favourable with low morbidity and excellent prognosis.

[Lumbar lateral recess stenosis. Clinical symptoms, diagnostic modalities and surgical management]

BACKGROUND

In spite of its importance for lumbar radicular syndroms only a few reports about lumbar lateral recess stenosis exist in literature. Most important clinical symptom is radicular pain, which may be exercise-dependent. Confirmation of diagnosis and differentiation from disc herniation requires imaging like CT, MRI or post-myelo-CT. Surgical treatment options include selective decompression techniques like foraminotomy, medial facettectomy and undercutting as well as hemilaminectomy, laminotomy and wide laminectomy or fusion.

METHOD

We treated 35 patients with selective decompression techniques.

RESULTS

In the follow-up 5 up to 18 months after surgery 25 patients for themselves described the results as good or excellent. Therefore, individually tailored selective microsurgical decompression is an appropriate and successful treatment strategy for lumbar lateral recess stenosis, if conservative treatment fails.

A new method for surgical repair of impression fractures of the cranial vault and frontal sinus with rivet-like titanium clamps

Conventional methods of stabilizing fragments in cranial impression fracture include the use of threads, wires, plates, etc. A new approach to facilitate this surgery is the use of titanium clamps, presented here in five cases, including one with frontal sinus fracture. Surgery was performed on admission day, with the exception of the sinus fracture. Compared with the use of mini- and microplates, the procedure was simple and short. The fixation was very rigid and the esthetic result excellent in all five cases. Skin irritation was minimal, compared with that from miniplates. Computed tomography and MRI compatibility due to artifacts are identical to those with miniplates.

A rare fatal course of disease in a patient with spontaneous pituitary apoplexy. Case report and literature review

A rare fatal course of a spontaneous pituitary apoplexy is described and its histological and pathophysiological causes are discussed. A review of the literature gives an overview of the historical and epidemiological data.

Intracavitary treatment of intrasellar cystic craniopharyngeomas with 90-Yttrium by trans-sphenoidal approach--a technical note

Intracavitary irradiation of intrasellar cystic craniopharyngeomas by stereotactic cyst puncture and injection of radioactive solutions is not yet possible. Therefore we designed a new method which allows such intracavitary irradiation. Its principle is a transphenoidal approach with only a small bony opening of the sella floor, followed by cyst puncture, exclusion of cyst leakage by Metrizamid injection under x-ray control, injection of Y-90-colloid solution at a dosage which delivers a radiation of 200 Gy to the cyst wall, and finally tight closure of the puncture site using fibrin glue and gelfoam. This method has been used in three patients with good results (follow-up 12-15 months) and without complications. Even though long-term follow-up is not yet available, our preliminary results suggest that this method will be useful for future patients with intrasellar cystic craniopharyngeomas.

The mapping and continuous monitoring of the intrinsic motor nuclei during brain stem surgery

A comprehensive technique was developed for continuous electrophysiological monitoring of intrinsic brain stem motor function during surgery to remove space-occupying lesions in the fourth ventricle and brain stem. The technique is analogous to that used during surgery in the cerebellopontine angle; motor nuclei and peripheral pontine fiber tracts of Cranial Nerves III-XII are identified by the electrical stimulation of structures in the operative field and the evaluation of the compound muscle action potentials recorded from the corresponding muscles of the head. Nerve function is monitored continuously by recording the ongoing electromyographic activity in these same muscles. Broadcasting electromyographic responses through a loudspeaker gives the surgeon immediate feedback on the status of the motor nuclei being monitored. Advantages of this technique include 1) the positive, objective identification of the nuclei and fiber tracts; 2) the continuous feedback on the status of these structures; 3) a safe approach through the fourth ventricle to the lesions in the brain stem; 4) the positive identification of the boundaries between the neoplasm and the motor structures of the rhomboid fossa; and 5) a warning to the surgeon of potentially harmful nerve manipulations (contact, dissection, transection) during surgery. After this technique was used in 16 consecutive operations to remove cavernomas (n = 9), gliomas (n = 4), and other types of tumors (n = 3), surgical and neurological results showed the method to be reliable and simple to perform.

Endothelin expression in normal human anterior pituitaries and pituitary adenomas

Endothelins (ETs) are important regulators of growth and function in many endocrine tissues. This study was designed to verify the expression of ETs in a series of normal human pituitaries and pituitary adenomas. We examined 13 normal pituitaries and 58 pituitary adenomas for the presence of immunoreactive (ir) ET-1 and ET-3. No ir-ET-1 was detected in any of the 13 normal pituitaries, whereas ir-ET-3 was observed in 4 of 13 (31%) cases. In contrast, 48% (28 of 58) of pituitary adenomas display immunoreactivity for ET-1, whereas 31% (18 of 58) show immunoreactivity for ET-3. With respect to the type of tumors, staining was as follows: nonfunctioning adenomas: ET-1, 14 of 33; ET-3, 9 of 33; somatotropinomas: ET-1, 8 of 16; ET-3, 6 of 16; corticotropinomas: ET-1, 5 of 5; ET-3, 2 of 5; and prolactinomas; ET-1, 1 of 4; ET-3, 1 of 4. Using double immunostaining, we found the colocalization of ET-3 in normal pituitaries and of ET-1 and ET-3 in pituitaries adenomas in each hormone-secreting cell. In Cushing adenomas, ET-1 was coexpressed in corticotropic cells in all 5 cases (100%). In the same tumors, by reverse transcriptase polymerase chain reaction, we investigated the presence of ET-1 and ET-3 messenger ribonucleic acids and found that they are expressed, respectively, in 18 of 21 and 7 of 11 tumors examined. Our findings demonstrate that pituitary adenomas frequently display ET-1 as well as ET-3 immunoreactivity, in contrast to normal pituitaries, in which only ET-3 was found.(ABSTRACT TRUNCATED AT 250 WORDS)

The treatment of spondylotic cervical myelopathy by ventral discectomy. Long term results on 121 patients

The pathophysiology of spondylotic cervical myelopathy is still a matter of discussion. This paper presents a series of 126 patients operated on using a ventral approach. In 47% of the patients only a spondylotic narrowing of the spinal canal was present and in 35% an additional disc herniation was found. In 13% of the cases however a soft disc without spondylotic spures was found and in 5% a dislocation of vertebral bodies. We found a marked male preponderance of 77%, mean age was 51.6 years, ranging from 25-50 years. Most patients were operated on at the levels of C4/5 and C5/6. Observation time covered a period of 3-10 years. The outcome was rated relatively to the preoperative degree of disablement using a questionnaire for the patients and their family doctors. We found a marked difference in the answers, especially in rating deterioration, which was stated by patients in 34%, by physicians only in 12%. Another finding was the time-related outcome. We found best results with 75% improvement and 5% deterioration between 3-6 months postoperatively, with increasing time the results decreased to 33% improvement, 33% identical statys and in 33% a deterioration related to the preoperative status must be noted.

An association of the RB gene with osteosarcoma: molecular genetic evaluation of a case of hereditary retinoblastoma

A 24-year-old male patient with hereditary retinoblastoma and a poorly differentiated osteoblastic osteogenic sarcoma was found to carry a mutant RB1 allele in all cells. This findings was most likely a point mutation or microdeletion because Southern blot analysis of peripheral blood DNA failed to disclose any structural aberration of the RB1 gene. A somatic mutation (deletion) affecting the other allele was found in the osteosarcoma cells. Management of tumor by external radiotherapy in early age is questioned because the effect of irradiation is to significantly increase the total incidence of second tumors above the already high incidence in non-irradiated patients.

Diagnosis and results of different treatment regimens in patients with spinal abscesses

Bacterial abscesses involving the spinal canal are associated with a high morbidity and mortality. Most frequently, these lesions are found in the epidural, rarely in the subdural space. In this report, our clinical material consists of a series of 16 patients treated during the last seven years. The clinical presentation included local neurological signs (back pain, para-/tetraparesis, bladder dysfunction), disturbances of consciousness (ranging from drowsiness to deep coma) and general inflammatory signs (meningism, fever). All patients presented with risk factors (septic foci, chronic diseases, and iatrogenic causes). Laboratory investigations revealed typically pathological blood sedimentation rate, leucocytosis and CSF-pleocytosis. Radiologically, the diagnosis was confirmed by myelography, CT and preferably MRI. The abscesses were located epidurally in 14 and subdurally in 2 cases. The surgical treatment included laminectomy, or multiple flavectomies in extensive lesions. Drainage systems (either simple silicon outflow drains or suction-/irrigation systems) were installed in all cases, as well as antibiotic treatment. Results of treatment: Following an observation period of 0.5-6 years, we found complete recovery in six (38%) cases, six (38%) others were mildly disabled and four (25%) patients died. Focussing on the results of the two different drainage systems, we found a statistically significant superiority of the inflow-/outflow system. Complications included mandatory re-exploration, post-inflammatory hydrocephalus, syringomyelia, spinal instability, surgical treatment of peripheral septic foci and therapy resistant septicaemia. In conclusion, we propose that spinal epi- or subdural abscesses require surgical evacuation, using a suction-/irrigation drainage system, as well as antibiotic and intensive care treatment.

Surgical observations in extremely lateral lumbar disc herniation

About 10% of lumbar disc herniations are localized in an extreme lateral position referred to as "extracanalicular". The clinical syndrome is a typical one with compression signs of the lateral, extra-foraminal nerve root and minimal lumbar pain. A reliable diagnosis can be made only since high resolution spinal computed tomography has become available. Surgical treatment will be rendered difficult by the "hidden" localisation of the disc fragments. A total number of 15 patients has been operated on in our department during the last year. In 10 patients, we used the lateral microsurgical approach proposed by REULEN, in five cases a combined procedure with lateral sequestrotomy and medial nucleotomy. In the first group, re-sequestration occurred in three cases and further surgery including medial nucleotomy was performed then. A good result with remission could be achieved in 13 cases, whereas in two cases with additional spondylolisthesis, lumbar back pain continued, but the radicular symptoms were reduced.

Benign symptomatic lesions of the pineal gland. Report of seven cases treated surgically

Seven patients with non-neoplastic symptomatic lesions of the pineal gland have been operated on in our department since 1988. Clinical symptoms were slight and there were intermittent signs of a space occupying lesions in the quadrigeminal area, i.e. visual and gait disturbances. In three patients, obstructive hydrocephalus with related symptoms was found. Diagnosis was confirmed by use of MRI in sagittal planes, revealing a cystic lesion in five and a solid tumour in two patients. All patients were operated on without complications using an infratentorial supracerebellar approach. Histological examination showed glial cysts of the pineal gland in five patients. In the two solid specimens, normal pineal tissue was found. These lesions seem to be of special interest, as the only pathological property are their size: Both lesions--"too large pineal glands"--caused obstruction of the outlet of the third ventricle with subsequent hydrocephalus. Surgical treatment was curative in all cases with prompt relief of the symptoms. Clinical symptoms and signs, diagnostic and pathological findings, as well as the surgical results of these cases will be reported.

Surgical treatment of patients with midline arachnoid cysts

Usually, arachnoid cysts are found in the Sylvian fissure (about 85%); midline arachnoid cysts are rare. Typical clinical symptoms are increased intracranial pressure, caused by a concomitant hydrocephalus, as well as visual and/or endocrinological disturbances. Six patients were examined, treated with one of two different surgical methods (cyst shunting or open treatment, either craniotomy/cyst membrane resection or laser endoscopy). Better results were observed following open treatment methods.

Evaluation of selective transsphenoidal adenomectomy by endocrinological testing and somatomedin-C measurement in acromegaly

A series of 29 previously untreated patients with acromegaly underwent transsphenoidal adenomectomy. Pre- and postoperative evaluation consisted of measuring growth hormone (GH) secretory dynamics during an oral glucose tolerance test (OGTT), the insulin hypoglycemia test, and the thyrotropin- and gonadotropin-releasing hormone (TRH/GnRH) test, and by obtaining the basal somatomedin-C level. After surgery, clinical and biochemical amelioration was achieved in all but two patients. In the whole group, basal GH and somatomedin-C levels decreased from a mean (+/- standard error of the mean) of 52.3 +/- 12.7 to 11.1 +/- 6.3 ng/ml and from 7.6 +/- 0.7 to 2.5 +/- 0.5 U/ml, respectively. Application of different criteria of cure revealed that 19 patients (66%) had basal GH levels below 5 ng/ml, 17 patients (59%) had normal somatomedin-C values, 16 patients (55%) had complete GH suppression (less than 1 ng/ml) during OGTT, and 13 patients (45%) met the above-mentioned criteria with disappearance of the paradoxical GH response to TRH/GnRH test. Evaluation of GH secretion by insulin hypoglycemia testing was useless in assessing the outcome after neurosurgery. When only patients with a normal somatomedin-C level and complete GH suppressibility during OGTT were considered "cured," the main favorable prognostic factor was intrasellar tumor localization, since 15 (75%) of 20 patients were "cured," as opposed to only one (11%) of nine with extrasellar extension of the adenoma. During the follow-up period, no tumor recurrence was detected in any of the "cured" patients. In these subjects somatomedin-C levels remained stable in all except two patients, who showed a slow increase within the normal range of somatomedin-C concentration. These data confirm that transsphenoidal surgery is the most effective form of treatment in previously untreated acromegalic patients and that normalization of somatomedin-C levels reflects normal GH secretion. Measurement of somatomedin-C could replace more extensive endocrinological testing during monitoring of treated acromegalic patients.

Transsphenoidal surgery with the additional use of the Nd-Yag-laser

100 Patients with pituitary adenomas were operated upon by the transsphenoidal route with additional use of the Nd-Yag-Laser. For this purpose, a suitable microsurgical handpiece has been developed. The energy output used in these operations was 30 W with a coagulation time not exceeding two seconds. Both the selectivity and radicality of the surgical procedure was documented by endocrinological investigation as well as by ophthalmological testing and radiological follow-up using high resolution CT and, more recently, Magnetic Resonance Imaging. When compared with the series of other authors, the selectivity as reflected by testing the anterior lobe functions pre- and postoperatively was not altered by the additional use of the Laser. The Nd-Yag-Laser seems to be a useful device in transsphenoidal surgery due to its potent coagulation effect and comfortable handling. If applied in a correct manner, there is no risk of additional damage to normal pituitary tissue and the surrounding structures. The possibility of coagulating tumour remnants, which cannot be removed by curettage, may increase also the radicality of the procedure.

Insulin hypoglycemia test and releasing hormone (corticotropin-releasing hormone and growth hormone-releasing hormone) stimulation in patients with pituitary failure of different origin

To investigate the efficacy of endocrine evaluation in diagnosing and localizing the cause of anterior pituitary failure, 17 patients with suprasellar space-occupying lesions, 4 patients with intrasellar tumors, 8 patients with no detectable anatomical lesion, 1 patient with posttraumatic failure and 1 patient with septooptical dysplasia were investigated. Endocrine evaluation consisted of measuring adrenocorticotropic hormone (ACTH), cortisol, and growth hormone (GH) levels during insulin hypoglycemia test (IHT) and after administration of corticotropin-releasing hormone (CRH) and growth hormone-releasing hormone (GRH). In addition, basal prolactin levels, gonadal and thyroid function were evaluated. The results showed that 4 of 17 patients with suprasellar tumors had normal ACTH and GH responses during IHT and after releasing hormone (RH) administration. Five of these patients had a normal ACTH or cortisol rise but no GH response during IHT. All 5 had a normal ACTH and 3 had normal GH rise after RH. Seven patients with suprasellar tumors had no ACTH or GH response during IHT, but all had an ACTH response to CRH. Only 3 of this group had a GH response to GRH. There was one exception of a patient who showed a GH and ACTH rise during IHT but only a blunted ACTH and no GH rise after RH administration. Four patients with pituitary failure and no demonstrable lesion had an ACTH rise after CRH but no GH rise after GRH, whereas in 3 patients with isolated ACTH deficiency no ACTH rise after CRH was seen. In 4 patients with nonsecreting pituitary tumors normal ACTH responses to IHT and CRH were seen, whereas GH rose during IHT only in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of surgical treatment in patients with arachnoid cysts

A retrospective study of 35 patients operated upon for arachnoid cysts during the last 10 years was carried out. In 19 patients treated by craniotomy, membrane resection and drainage into the basal cisterns, clinical improvement could be noted in 13 cases. Correspondingly on the CT-controls the cysts were found to have disappeared in two cases and were reduced in size in seven patients. In 11 patients, however, who were initially treated by a shunting procedure, seven patients became free of symptoms. Postoperative CT-controls showed in three cases a significant reduction of the size of the cyst, which remained unchanged in two other cases. In five patients with the combination of a nonspace-occupying arachnoid cyst and subdural effusions, drainage of the latter only was sufficient to relieve the clinical symptoms. The prominent findings were the high complication rate of the primary or secondary shunting procedures (48%), as well as the close correlation between the clinical outcome and the postoperative CT-controls.

[Magnetic resonance imaging in craniopharyngiomas. The differential diagnosis of cystic intra- and suprasellar space-occupying lesions]

Seven patients with confirmed craniopharyngiomas were examined via magnetic resonance imaging. The various tumour components (whether solid, cystic or calcified) were evaluated separately. Three types of cysts were observed that can be distinguished by their signal intensity in various pulse sequences. This could be explained largely by an analysis of the T1 and T2 image contrast. The reason for the various types of cysts is determined by their cholesterol content. MR imaging is not as useful as CT for demonstrating the solid and calcified portions of the tumour and this reduces its value in diagnosing the type of tumour. Against that, it is superior with regard to separating the tumour from its neighbouring structures. The differential diagnosis, which must be considered in using MR, is summarised in a table at the end of the paper.

Postoperative controls in surgically treated hormonactive pituitary adenomas by use of magnetic resonance imaging

The search of reliable imaging methods to detect the substrate for persisting hypersecretion in patients operated on for hormonactive pituitary adenoma prompted us to study the possibilities of the newly available Magnetic Resonance Imaging (MRI) technique in this regard. Pre- and postoperative MRI-studies where performed in 5 patients with persisting GH excess following transsphenoidal surgery as well as in 3 patients with micro- and 2 patients with macroprolactinomas. The MRI-findings were correlated with the results of the endocrinological examinations. Two acromegalic patients and three cases with microprolactinomas, who were successfully operated upon as defined by the functional criteria were also included to obtain a baseline for normal postoperative findings. The MRI-study was positive in all of the five patients with persisting GH-overproduction. In prolactinomas, the substrate of hypersecretion could only be detected, when the PRL-value exceeded 2,000 microU/ml. MRI may present an important diagnostic method for evaluating further treatment options in patients with remaining hormonal hypersecretion following transsphenoidal adenomectomy, particularly with regard to a second surgical approach.

Neurosurgical experience with magnetic resonance imaging in sellar lesions

41 patients with various sellar and parasellar lesions (pituitary adenomas, meningiomas, optic gliomas, craniopharyngeomas and granulomas), who underwent surgery consecutively, were studied by MRI investigations. In 10 patients post-operative MRI controls were performed. The information obtained by the MRI were compared with the other radiological investigations (especially coronar and axial high resolution CT), and the intra-operative findings. The advantages of MRI in the diagnosis of sellar lesion are demonstrated by exemplary cases.

Recurrent pituitary adenomas

Based on 880 pituitary adenomas operated upon between 1972 and 1982 the diagnostic and therapeutical strategy in recurrences is discussed. The incidence of reoperations was 7.75%, 3.7% in hormonally inactive and 4.1% in hormonally active recurrences. The rate was 30% after transcranial surgery--due to the extension of the tumours--and 5% after the trans-sphenoidal approach. In hormone inactive adenomas visual impairment in 29 out of 50 recurrences caused a second operation combined with radiotherapy in 13 cases. Radiotherapy alone was used in 17 cases. In hormonally active adenomas the treatment of persistent hormonal excess represents the main therapeutical problem. With HGH-producing adenomas a return to normal was achieved in 22 cases mainly by a combination of reoperation and radiotherapy (12) or radiotherapy (8) alone. Radiotherapy should be avoided in young patients whenever possible. The procedure of choice in PRL-producing adenomas (14 cases) seems to be treatment with dopamine-agonists (9). An additional reoperation was necessary in five cases.

[Value of nuclear magnetic resonance tomography in the diagnosis and therapy outcome of prolactinomas]

30 MR tomographies were performed in 15 patients suspected of having a prolactinoma on account of clinical examinations and test in the chemical laboratory. The T1 and T2 times of the adenomas were determined quantitatively. In addition, high resolution CT imaging had been performed in all patients. The signal performance of the normal pituitary gland determined in 11 healthy persons on the basis of quantitatively measured T1 and T2 times, was found to largely correspond with that of grey matter of the brain. Of the 14 confirmed prolactinomas, 11 were microadenomas and 3 macroadenoma. Solid adenomas were identified by enhanced T1 values. It was possible to differentiate these from cystic, haemorrhagic and necrotic tumour components by differences in signal performance. 7 patients on drug therapy with dopamine agonists were controlled by means of MR tomography. No measurable size reduction of tumour was seen in 3 patients with cystic or haemorrhagic tumour components. On the other hand, tumour reduction was seen after brief drug therapy in 2 macroprolactinomas and one microprolactinoma. An essential advantage offered by MR is, besides the absence of exposure to radiation, in the first place the better and more precise information on the relative position of the adenoma with reference to the vessels and the optic chiasm, and, secondly, better identification of cystic and haemorrhagic processes within the prolactinoma.

[Early diagnosis and treatment of aneurysmal hemorrhages (author's transl)]

The diagnostic and therapeutic procedures after aneurysmal hemorrhage are described. The most important aspects in history-taking, indication for lumbar puncture, the evaluation of computer tomographic findings and the method of angiography are presented and in particular the timely coordination of the preoperative measures and the operation is commented on.