[Feedback control of depth of anesthesia during propofol administration. Bispectral index as the controlled variable]. / Regelkreisgesteuerte Narkosetiefe bei Propofolapplikation. Verwendung des Bispektralindex als Regelungsgrösse.

BACKGROUND: The objective of this study was to evaluate the performance of a new system for closed-loop control of propofol administration using the bispectral index (BIS) under total intravenous anesthesia in the index values of middle-to-deep depth of anaesthesia. METHODS: In this study 20 adult patients anesthetized with propofol and remifentanil were investigated. The propofol infusion was carried out using a fuzzy-PD+I controller with a target BIS value of 40. RESULTS: Closed-loop control was able to provide maintenance of anesthesia and adequate operating conditions for all patients. The following quality control criteria were calculated: median performance error (MDPE; 0.16%, SD +/-1.4%), median absolute performance error (MDAPE; 6.9%, SD +/-2.8%) and wobble (6.8%, SD +/-2.5%). CONCLUSION: The present study showed the clinical feasibility of the controller compared to existing devices regarding a high level of quality criteria of a model with an implemented fuzzy-PD+I structure controlling depth of hypnosis.

Stereotactic atlantoaxial transarticular screw fixation.

Atlantoaxial stabilisation can be performed using a variety of surgical techniques. Developments in spinal instrumentation and stereotactic technology have been incorporated into these procedures. We have recently adopted frameless stereotaxy to assist in such operations. A retrospective study of patients treated by the authors and using frameless stereotaxy from 2001 to 2002 was performed. Each patient underwent pre-operative fine-cut CT in the position of fixation. Using these images, screw trajectory was planned. Stereotaxis and fluoroscopy was utilised during fixation. A post-operative CT was performed. There were nine patients. Bilateral screw placement was achieved in eight. In the remaining case stereotactic planning predicted the single screw fixation. There were no post-operative complications. Post-operative CT showed screw placement corresponding to the planned trajectory in all 17 screws. Stabilisation was achieved in all. Stereotactic atlantoaxial screw fixation is an accessible, safe and accurate method for the management of C1-2 instability.

Corticotroph pituitary carcinoma: case report and literature review.

Pituitary carcinomas, currently defined as primary adenohypophyseal neoplasms with evidence of either brain invasion or metastatic spread, are exceptionally rare. A case of corticotroph pituitary carcinoma is reported. A 17-year-old female first presented with an invasive and clinically non-functioning pituitary macroadenoma. The primary pituitary lesion lacked atypical histological features and retrospective immunohistochemical studies confirmed its corticotrophic nature. Repeated episodes of local recurrence followed together with the acquisition of severe Cushing's disease. Local disease control was not obtained despite repeated surgical decompression and courses of radiation therapy. Systemic dissemination with multiple bone metastases became manifest eleven years after the first presentation. Atypical histological features and Crooke's hyaline change were evident in both the recurrent and metastatic disease. She remains alive at last follow-up with severe complications relating to persisting sellar and metastatic disease and ongoing endocrine dysfunction. A further 32 cases of pituitary corticotroph carcinoma reported in English are reviewed to highlight the clinicopathological features of this rare form of pituitary neoplasm. Difficulties associated with the diagnosis and management of pituitary carcinoma are also discussed.

Arachnoiditis ossificans and syringomyelia: a unique case report.

A 62-year-old male presented with progressive quadriparesis. Magnetic resonance imaging of the spine revealed a spinal cord syrinx but failed to detect extensive arachnoiditis ossificans noted on insertion of a syringopleural shunt. A postoperative computed tomography scan clearly demonstrated the abnormality and its extent. We present a rare case of syringomyelia resulting from spinal arachnoiditis ossificans and review the relevant literature.

Treatment of an intracranial germinoma spinal metastasis.

A 20-year-old male with a solitary intradural extramedullary spinal metastasis from a pineal germinoma presented with progressive spinal cord compression. This was initially treated with radiotherapy and the patient showed rapid clinical improvement with complete resolution of his neurological symptoms and signs. Subsequent systemic chemotherapy resulted in complete radiological resolution of the lesion. This case is presented to demonstrate radiotherapy and chemotherapy as a treatment option for germinoma 'drop' metastasis causing spinal cord compression, along with a review of the literature.

Internal carotid artery dissection: an animal model?

This paper describes an internal carotid artery (ICA) dissection model in a rabbit. An animal model for ICA dissection has not been described. New Zealand White rabbits were anaesthetized and surgical microdissection performed to expose the right internal carotid artery. A small arteriotomy was performed and a subadventitial plane of dissection created using blunt dissection and injected heparinized saline. The adventitia was sutured and the animals were recovered after closure of the wound. The procedure was repeated on the left ICA after 7 days with removal of the left ICA for control samples and removal of the right ICA to obtain sample specimens. The brain was also removed. A total of 11 control specimens and 9 sample specimens were obtained. The mean length of these specimens (n = 20) was 5.5 mm (range 5-6 mm). The mean length of dissection of the control specimens (n = 11) was 2.2 mm (range 2-3 mm). The mean length of dissection on sample specimens (n = 9) was 2 mm (range 1-3 mm). There was no extension of the arterial dissection. There was no intraluminal thrombosis or cerebral infarction. This model was able to induce arterial wall dissection in a rabbit. There was no extension of the induced dissection over 7 days. No local arterial or cerebral ischemic complications developed from the dissection.

Orbitocranial penetration by a fern: case report.

OBJECTIVE AND IMPORTANCE: Cranial and orbitocranial penetration by organic foreign material is not infrequent. It is important to identify whether penetration has occurred and to localize and remove the organic foreign material. CLINICAL PRESENTATION: We report a 15-month-old patient who suffered orbitocranial penetration with the stem of a fern. The stem passed through the orbit, exiting via the superior orbital fissure. It continued through the middle cranial fossa to end in the posterior cranial fossa. INTERVENTION: The patient underwent surgery, and a modified Dolenc procedure was performed. The foreign body was identified in the prepontine cistern and was removed. An extradural approach was performed to the cavernous sinus and superior orbital fissure, and the remaining foreign body was removed. CONCLUSION: Retained intracranial wood should be removed. The radiological diagnosis can be difficult, and magnetic resonance imaging is the investigation of choice. Magnetic resonance imaging may not detect some cases of organic foreign material penetration.

Spinal dysraphism and the Currarino triad.

A female born with a lumbosacral lipomyelomeningocele, an associated foot-shaped appendage attached to her sacrum, sacral dysgenesis, anal atresia, a recto-vaginal fistula and duplication of the right ureter is reported. We consider this case represents a pygomelus associated with a lipomyelomeningocele and an incomplete expression of Currarino's triad.

Clostridium septicum as a cause of pericarditis and mycotic aneurysm.

Clostridium septicum is a bacterial species associated with gas gangrene in both humans and animals. Although not usually a pathogen in humans, it has been implicated in some cases of abscesses and bacteremia. We now report the first case of pericarditis with mycotic aneurysm due to C. septicum.

Toxic shock syndrome associated with TSST-1 producing coagulase-negative staphylococci.

Coagulase-positive staphylococci have been isolated from more than 95% of cases of toxic shock syndrome (TSS). Toxic shock syndrome toxin-1 (TSST-1) is produced in more than 90% of cases. A case is described of recurrent TSS in which a coagulase-negative staphylococcus was isolated from the vagina and produced TSST-1. No coagulase-positive staphylococci were isolated. Coagulase-negative staphylococci should be considered as causative agents in cases of TSS. Assay for TSST-1 should be performed on coagulase-negative staphylococci obtained from the appropriate clinical sites if no coagulase-positive staphylococci are isolated.

Conductivity values of tissue culture medium from 20 degrees C to 40 degrees C.

Few studies are available that relate conductivity and temperature in solutions commonly used in tissue culture media. The purpose of this paper is to provide equations relating conductivity and temperature (in the range 20 degrees C-40 degrees C) for five solutions: 0.9% saline, MEM (Minimum Essential Media), horse serum, MEM with 1% horse serum, and MEM with 10% horse serum.

Plasmids expressing the Herpes simplex virus thymidine kinase gene in mammalian and bacterial cells.

Two plasmids containing either the complete thymidine kinase gene of Herpes simplex virus type I (pSK2) or the gene without the remote control sequence (pSK1) just behind the lac promoter and the first codons of the lacZ gene were constructed. Both plasmids efficiently transform mouse Ltk- cells as well as E. coli tk- cells to the Tk+ phenotype and are well suited for plasmid rescue from transformed mouse cells by direct functional selection for tk expression using a tk- mutant of E. coli C600.

Miniature ELF electric field probe.

A miniature ac electric field probe having direct electrical connections with its battery-operated electronics is described. Because its small size introduces little field perturbation, fields generated by relatively small electrode structures in laboratory environments can readily be characterized.