John Koivukangas

Incidence of Pituitary Adenomas in Northern Finland in 1992-2007

CONTEXTnData on the incidence of pituitary adenomas (PAs) are scant and outdated. A population-based regional cohort with thorough case identification was used to evaluate the incidence of clinically detected PAs in the era of magnetic resonance imaging.nnnOBJECTIVEnThe objective of the study was to describe the age- and sex-specific incidence of all PA subgroups, with data on incidentally found PAs, pituitary apoplexies, and time trends.nnnDESIGN, SETTINGS, AND PATIENTSnThis was a retrospective descriptive analysis of PA patients diagnosed during 1992-2007 in Northern Finland (NFi).nnnMAIN OUTCOME MEASUREnWorld Health Organization 2000-standardized incidence rates (SIRs) of PAs per 100,000 were measured.nnnRESULTS AND CONCLUSIONnThe final cohort consisted of 355 PAs. The incidence rates of the Oulu University Hospital regional district were used as a reference to assess the applicability of our case finding over the rest of NFi. Incidence rates of all PA subgroups except microprolactinomas were statistically equal between these areas; thus, all presented SIRs are based on the NFis cohort except Oulu University Hospital regional district-based prolactinomas and PAs overall. Overall SIR of PAs was higher (4.0 per 100,000) than in previous reports. Prolactinomas had the highest SIR: 2.2 per 100,000, followed by clinically nonfunctioning PAs (1.0) and GH-secreting (0.34), ACTH-secreting (0.17), and TSH-secreting (0.03) PAs. The gender-specific SIR was 2.2 per 100,000 in males and 5.9 per 100,000 in females. Pituitary apoplexy occurred as a presenting symptom in 11% of clinically nonfunctioning PA patients. The SIR of incidentally discovered PAs increased significantly from 1992-1999 to 2000-2007 (0.59 to 1.6, respectively; P < 0.01), which accounted for the perceived increasing trend in the overall SIR of PAs (3.8 to 4.2; P > 0.05).

The terminal prostaglandin synthases mPGES‐1, mPGES‐2, and cPGES are all overexpressed in human gliomas

Prostaglandin E2 has been connected to processes promoting tumor growth in several human malignancies including gliomas. The terminal prostaglandin synthases mPGES‐1, mPGES‐2, and cPGES convert PGH2 into prostaglandin E2. The inhibition of their function could significantly reduce PGE2 levels in tumors while avoiding some side effects related to the inhibition of the upstream enzymes COX‐1 and COX‐2. In this study, the immunohistochemical staining of mPGES‐1 and, for the first time, the staining of mPGES‐2 and cPGES are characterized and compared with COX‐1 and COX‐2 staining in the same tumor samples of 94 human gliomas. The main results demonstrate over‐expression of all three proteins, including cPGES and mPGES‐2 that are commonly considered non‐inducible, in both low‐ and high‐grade tumors. For all three proteins, average expression in tumor cells was higher in grade III tumors than grade II tumors. The analysis showed no correlation between tumor grade and staining of tumor cells or vascular endothelium with any of the antibodies except in oligodendrogliomas where moderate correlation (linear correlation coefficient 0.6; Pu2003<u20030.01) could be found between tumor grade and tumor cell staining with mPGES‐1 and cPGES. In grade II tumors which recurred and were reoperated upon during the data gathering period, average expression of COX‐2, mPGES‐1, and cPGES was higher than in tumors that were operated on only once. Our results demonstrate the significance of all three terminal prostaglandin synthases, mPGES‐1, mPGES‐2, and cPGES, as a possible future target of inhibition in glioma therapy.

Technical accuracy of optical and the electromagnetic tracking systems

Thousands of operations are annually guided with computer assisted surgery (CAS) technologies. As the use of these devices is rapidly increasing, the reliability of the devices becomes ever more critical. The problem of accuracy assessment of the devices has thus become relevant. During the past five years, over 200 hazardous situations have been documented in the MAUDE database during operations using these devices in the field of neurosurgery alone. Had the accuracy of these devices been periodically assessed pre-operatively, many of them might have been prevented.The technical accuracy of a commercial navigator enabling the use of both optical (OTS) and electromagnetic (EMTS) tracking systems was assessed in the hospital setting using accuracy assessment tools and methods developed by the authors of this paper. The technical accuracy was obtained by comparing the positions of the navigated tool tip with the phantom accuracy assessment points. Each assessment contained a total of 51 points and a region of surgical interest (ROSI) volume of 120x120x100 mm roughly mimicking the size of the human head.The error analysis provided a comprehensive understanding of the trend of accuracy of the surgical navigator modalities. This study showed that the technical accuracies of OTS and EMTS over the pre-determined ROSI were nearly equal. However, the placement of the particular modality hardware needs to be optimized for the surgical procedure. New applications of EMTS, which does not require rigid immobilization of the surgical area, are suggested.

Intraoperative ultrasound imaging in lumbar disc herniation surgery

SummaryThe diagnosis of lumbar disc herniation has improved with metrizamide rhizography and CT. Also, visualization of the operative site has been enhanced with use of the operating microscope. However, evaluation of the completeness of herniated disc removal can be difficult, especially in the case of medially located lesions. Also, intradural extension of the herniation can be impossible to rule out in some cases without intradural exploration. Intraoperative ultrasound imaging is safe, rapid and readily available in most hospitals. Its application to real-time imaging control of 10 selected cases of herniated lumbar disc showed that the herniated material could be visulalized in relation to the interspace and dural sac in all cases. The effect of removal of the herniation on nerve root compression could also be evaluated. Especially in cases involving extension of the herniation to the medial region under the dura, or into the intradural space, the removal of herniated material could be adequately confirmed without the need for further manipulation with surgical instruments. With appropriate transducer design and frequency, the method can be applied to microsurgical technique to rule out sequestration outside of the surgical exposure.

Role of quality of life in therapeutic strategies in brain tumors.

The results of the surgical management of brain tumors have improved considerably with the development of new technology. One of the current problems is the evaluation of results of surgical treatment of infiltrative brain tumors, for example, the low-grade astrocytoma. This paper centers on the evaluation of changes in quality of life based on in-depth qualitative, together with some quantitative, data on quality of life of 4 representative cases of cerebral astrocytoma. Results of clinical evaluation (Karnofsky scale, Glasgow Outcome Score) and semi-structured theme interview showed improvement of quality of life during the first post-treatment year in all cases. This was particularly noted in social aspects of quality of life, including the effect of reduced symptoms on social interaction. The patients own evaluation of the quality of their lives was not influenced only by the illness and treatment, but also by general life circumstances, such as social relations and work. The study further provides some basic data that can be used to develop questionnaires for evaluation of results of the treatment of these patients.

Neuronavigator-Guided Cerebral Biopsy

Neuronavigators are new dynamic interactive instruments that use on-line computers to orient imaging data to the surgical field and guide the neurosurgeon to his target. We have been working since 1987 on a neuronavigator that serves not only as a precise pointer, but also as a dynamic arm that can be used to hold instruments, such as biopsy guides. The neuronavigator arm consists of six joints with optical encoders and is attached to the Mayfield headholder. The arm is connected to a workstation running customized 3D image graphics software. Special instruments and surgical technique have been developed. Here, we report on early clinical experience with ten biopsy procedures: 4 low-grade and 3 high-grade astrocytomas, one craniopharyngioma and one chronic intracerebral haematoma and intracerebral cyst, both of the latter with surrounding tumour suspect tissue. In all glioma cases serial biopsies were taken from optimal sites under ultrasound imaging control. Eight cases showed representative tumour tissue, while in two cases neoplasia was ruled out. The neuronavigator proved to be versatile, allowing comprehensive imaging data to be adapted to the surgical field.

Computer-guided Laser For Neurosurgery

On the basis of over 40 neurosurgical laser operations, including CO2, Nd-YAG and simultaneous CO2/Nd-YAG laser procedures, a computer-guided system for spatial control of the laser beam has been developed. The pilot laser has several modes: it can direct the neurosurgeon along the central axis of the surgical microscope to stereotactically determined point-like targets or outline selected layers of underlying volume targets onto superficial surfaces such as scalp and cortex and onto the tissue at the appropriate depth. The active treatment laser can be guided by preoperative CT/MRI or intraoperative ultrasound image data for layer-by-layer resection of tumor. The laser system can be connected to the surgical field by rigid stereotactic means or by neuronavigator. In the present system, a special brain surgery adapter coordinates the imaging system and laser to the surgical field. Thus, the laser system can be used for image-guided surgical orientation, for demarcation of lesions and for actual layer-by-layer removal of tumor.

Somatization symptoms are related to right-hemispheric primary brain tumor: a population-based prospective study of tumor patients in northern Finland.

BACKGROUNDnSomatization symptoms have been found to be early symptoms of tumor among brain tumor patients.nnnOBJECTIVEnThe authors followed patients through diagnosis of brain tumor and subsequent surgery.nnnMETHODnPatients with a supratentorial tumor were given repeated measurements for somatization with the Crown-Crisp Experiential Index.nnnRESULTSnBefore tumor operation, the patients with a tumor in the right hemisphere had significantly higher somatic anxiety scores than those with a tumor located in the left hemisphere. The specific symptoms were dizziness and palpitation among patients with a right hemispheric tumor.nnnCONCLUSIONnIt is important to remember possible very unusual causes behind somatization symptoms.

Neurosurgical Navigation System

A mechatronic system for neurosurgical simulation before operation as well as for orientation during surgery is presented. The system consists of a six-jointed robotic arm, workstation and customized 3D visualization software. The robotic arm is used to rigidly transfer multiple image data to the surgical volume. The system has been used in several biopsy and other intracranial operations with good results.

Design of visualization system for neurosurgical workstation

A visualization system for simulating nellrosurgical operations and helping in the orientation during neurosurgical procedures is presented. The system generates 3D and 2D reconstructions from preopertive M R and CT images. These reconstrllctions help in conjunction with intraoperative ultrasound the neurosurgeon in localizing the target in the brain tissue before craniotomy and during the opertion. The system is controlled by a mouse or speech in preoperative planning, while during the operation the neurosurgeon needs to use only voice control tlws leaving hands free. The flexible, expandable and portable design allows the visualization system to grow with the neurosurgical workstation.