Biomedical subjects

E M Laasonen

Publications and source records attributed to E M Laasonen.

At least 19 recordsLinked to original sources

PubMed2002

Virtual endoscopy imaging of the middle ear cavity and ossicles.

Ten cadaver temporal bone blocks were studied with high-resolution computed tomography (HRCT) in order to produce topographic images, which are more informative than ordinary CT slices. Virtual endoscopic images were produced with separate, commercially available software, paying attention to the middle ear cavity and ossicles. Four major viewing locations for virtual endoscopy (the ear canal, hypotympanum, attic and eustachian tube) developed images acceptably. The malleus and incus were visualized properly. Small structures such as the lenticular process and the stapes sometimes failed to have good imaging. The eustachian tube and attic virtual views, which are usually not receptive to ordinary endoscopy, gave proper visualization of middle ear structures. Even the smallest structure, the stapes, can produce a virtual image.Virtual endoscopic images, or topographic images, of the middle ear and ossicles contribute to the understanding of the anatomy of the middle ear, thus enhancing the chances for successful surgery.

Adult↗

PubMed2001

Comparison of CT and fiberoptic video-endoscopy findings in congenital dysplasia of the external and middle ear.

Twenty-six ears (of 25 patients) with congenital dysplasia of the external and middle ear were studied with two different types of imaging technologies in order to find out if it is possible to improve the anatomical overview of the dysplastic middle ears by combining the imaging methods. All the 26 ears were studied with computed tomography (CT), which gave cross-sectional images of the tympanic cavity. A fiberoptic video-endoscope (FVE) was introduced through the nose and via the Eustachian tube into the middle ear so that the topographic view of the anatomical structures of the middle ear could be visualized. Some structures were visualized better with FVE than with CT and vice versa. We concluded that the combined information obtained from these two imaging technologies provided a better understanding of the structural anatomy of a congenital dysplastic middle ear.

Abnormalities, Multiple↗

PubMed1999

Patient outcome after endovascular treatment of intracranial aneurysms with reference to microsurgical clipping.

OBJECTIVES: Endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDC) has found growing acceptance worldwide, and partially replaced conventional microsurgery. In this study clinical and angiographical results of embolization are reviewed. In addition, long-term neuropsychological patient outcome with reference to surgery is assessed. Indications for screening and follow-up of the patients as limitations and recent achievements of aneurysm embolization are discussed. MATERIAL AND METHODS: Angiographical and clinical follow-up of the first 44 patients with 48 GDC-coiled aneurysms are reviewed. Postprocedural clinical, emotional and social (CES) outcome on disability scale as scored from postal questionnaire data is presented and compared to 106 currently operated patients. RESULTS: In 75% of the embolized aneurysms successful occlusion was achieved, procedural mortality was 2.3% and morbidity 18.2%. Clinical status of all 15 patients with unruptured aneurysms preserved. Of the surviving 29 patients with ruptured aneurysms 12 improved and the rest preserved their clinical status. In 91% of the embolized patients and in 85% of the operated patients CES outcome was categorized as good or excellent. The difference was statistically nonsignificant. CONCLUSION: Embolization with GDC is a feasible, effective and safe mini-invasive method in small aneurysms with a small neck. However, intentional parent artery occlusion, novel endovascular techniques and embolic agents or supplementary surgery may be necessary in selected cases. Neuropsychological long-term outcome of the patients treated for an intracranial aneurysm does not differ much between GDC embolization and microsurgical clipping.

Adolescent↗

PubMed1999

MR angiography with three-dimensional time-of-flight and targeted maximum-intensity-projection reconstructions in the follow-up of intracranial aneurysms embolized with Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Intra-arterial contrast angiographies are generally used to confirm treatment results of endovascular neurointerventions such as aneurysm obliteration. We compared MR angiography with digital subtraction angiography (DSA) as a follow-up technique for the detection of aneurysmal remnant cavities and arterial patency in patients treated for intracranial aneurysms with Guglielmi detachable coils (GDCs). METHODS: In 20 consecutive patients, follow-up MR angiography and routine intra-arterial cerebral angiography were performed on the same day 1 to 7 months (mean, 4.5 months) after embolization with GDCs. MR angiographic data were postprocessed for subvolume maximum intensity projections centered on the region of the treated aneurysm. Hard copies of both imaging studies were interpreted independently in a blinded fashion to record and compare remnant cavities, location of residual flow, and adjacent arterial narrowing, using DSA as the standard of reference. The interpreters also established an occlusion grade for the treated aneurysms as evidenced on DSA images and evaluated MR angiograms for artifactual effects. RESULTS: Overall sensitivity and positive predictive value of MR angiography in revealing aneurysmal remnant cavities were both 90%. Specificity in ruling out a remnant cavity with MR angiography was 91%. One remnant cavity was missed by MR angiography, and in five patients, false adjacent arterial encroachments were reported. CONCLUSION: MR angiography may be useful in the long-term follow-up of successfully treated small and medium-sized aneurysms after concurrent primary verification of their occlusion with DSA.

Adult↗

PubMed1998

Visualization of the middle ear with high resolution computed tomography and superfine fiberoptic videomicroendoscopy.

Ten temporal bone blocks were dissected from fresh postmortem specimens from patients succumbing to diseases unrelated to the ears. A superfine fiberoptic videomicroendoscope (SFV) was introduced through the eustachian tube into the middle ear, and middle ear structures were visualized. The cadaver temporal bone blocks were also studied with high-resolution computed tomography (HRCT). When HRCT gave good results SFV did not succeed well and vice versa. However, SFV provided topographic anatomical information of the middle ear structures while HRCT gave cross-sectional images of the anatomy of the tympanic cavity. The different types of information obtained by the two imaging technologies supplement each other and were found to improve diagnosis in such cases as external ear canal atresia.

Adult↗

PubMed1998

Endovascular treatment of carotid-cavernous fistulae.

INTRODUCTION: In the embolotherapy for the treatment of carotid-cavernous fistulae (CCF) several embolic agents and techniques have been reported. In this series the efficiency of transarterial electrothrombosis with Guglielmi detachable coils (GDC) in direct fistulae and the occlusion with particles, tissue glue and platinum coils in indirect fistulae is studied and the implications of these findings is discussed regarding classification, conservative therapy and follow-up. MATERIAL AND METHODS: Eleven consecutive patients were reviewed retrospectively. Four patients had direct high flow fistulae from the internal carotid arteries and the rest had low flow dural fistulae. Postprocedural clinical outcome and angiographical follow-up are presented. RESULTS: Six patients became symptom free, in 4 patients the symptoms resolved and 1 patient suffered a minor procedural complication. In the 8 follow-up angiographies the fistulae of 7 patients were totally closed, including the 4 patients with direct fistulae. CONCLUSION: Progressive clinical manifestations require embolization to alleviate the symptoms and to prevent further complications of the arteriovenous shunting. Embolization with GDC is a feasible, effective and safe method in direct fistulae.

Adolescent↗

PubMed1997

Diagnosis and embolizing of spinal arteriovenous malformations.

Spinal arteriovenous malformations are uncommon disorders associated with considerable difficulty in diagnosis and treatment. They are divided into dural arteriovenous fistulas and intradural medullary spinal cord angiomas. In this retrospective series of six patients the clinical outcome of embolization is presented. The patient material consisted of three dural fistulas and three cord angiomas, one of which bled causing sudden paresis, pain and incontinence. In the remaining five patients the symptoms were progressive consisting of paraesthaesias, paraparesis, pain and incontinence. The clinical status of four patients was not changed after the treatment, one deterioriated and one improved. There were no bleedings after the therapy. In one patient spinal angiography for follow-up was performed and recanalization was seen in the dural fistula after particle embolization. Also, in one cord angioma embolized with particles reflow appeared in the immediately repeated angiography. For permanent angioma occlusion tissue adhesive is preferred as embolic material. Surgical therapy as an alternative or adjuvant to embolization is discussed with a review of the literature. Early timing of the therapeutic intervention is stressed to avoid the development of irreversible ischaemic medullopathy and to prevent haemorrhage. The therapeutic procedures at the early stage of the disease may be curable or, at least, halt the progression of the symptoms. Cross-sectional imaging studies and myelographies may reveal the lesion. For the definitive diagnosis of spinal angioma with its vascular feeders and for the evaluation of its occlusion grade after the therapy selective spinal angiography is needed.

Adolescent↗

PubMed1994

Emergency CT in blunt abdominal trauma of multiple injury patients.

Multiple injury patients with blunt abdominal trauma (n = 110) were examined by abdominal CT. An i.v., but not peroral, contrast medium was used, thereby eliminating the delay caused by administering peroral contrast medium and any subsequent delay in making the diagnoses and beginning operative treatment. Eighteen patients underwent emergency laparotomy after the initial CT examination. The preoperative CT findings were compared to the laparotomy findings. CT revealed all but one of the severe parenchymal organ lesions requiring surgery. The one liver laceration that went undetected had caused hemoperitoneum, which was diagnosed by CT. The bowel and mesenteric lesions presented as intra-abdominal blood, and the hemoperitoneum was discovered in every patient with these lesions. Fourteen patients also initially had positive abdominal CT findings; 10 of them underwent an additional abdominal CT within 3 days, but the repeat studies did not reveal any lesions in need of surgery. Omission of the oral contrast medium did not jeopardize making the essential diagnoses, but it did save time.

Abdominal Injuries↗

PubMed1991

Lumbar spine interbody fusion with reinforced hydroxyapatite implants.

Porous coralline and synthetic hydroxyapatite blocks reinforced with either self-reinforced polyactide or polyglycolide were implanted into 15 lumbar intervertebral disc spaces in five minipigs in order to determine whether they could provide an osteoconductive bridge for interbody fusion. Histological examination and radiological analysis with plain films, computed tomography and magnetic resonance imaging were carried out. The osteoconductive properties were promising; creeping bone formation could be observed, although no complete fusion had been achieved at 24 weeks.

Animals↗

PubMed1991

Delayed diagnosis of extremity injuries in patients with multiple injuries.

A total of 340 patients treated in the Intensive Care Unit of the Department of Orthopedics and Traumatology at Helsinki University Central Hospital were analyzed in this study. They had in all 1,071 fractures and luxations of the pelvis and extremities, of which the trauma surgeons and radiologists on duty initially missed 45 injuries, i.e., 4.2%. Taking into account the eventual late symptoms, the most severe delayed diagnoses were of injuries located around the hip and knee joints. The patients with delayed diagnoses were, on the average, the most severely ill: their needs for primary blood transfusions and assisted respiration resembled the needs of patients who later died of their trauma or its complications. The most common causes of the delay in diagnosis were: radiographs not done in 60% of patients, and no notation of visible injury in radiographs in 31%. Inferior quality of radiographs, unnoticed radiologists' reports, a fracture visible at the outermost corner of a radiograph, a fracture hidden by other fractures, or excessive obesity of the patient may also contribute to a delay. The study presents measures for improving diagnostic strategies, but it would appear that delayed diagnoses cannot be totally eradicated.

Extremities↗

PubMed1990

Posttraumatic lumbar intraspinal extradural-intradural ossification.

A case of intraspinal calcification having mainly the configuration of an intradural cast is presented. The traumatic etiology is obvious, and we consider, that the dural sac and nerve root lacerations were associated with intradural as well as extradural hematomas, which later became calcified.

Adult↗

PubMed1990

Chronic unilateral low-back pain. Predictors of outcome of facet joint injections.

One hundred nine patients with chronic (3-36 months; mean, 13.4 months) unilateral low-back pain and no signs of sciatica were subjected to facet joint injection, randomized in three therapy groups: cortisone and local anesthetic injected intra-articularly, the same mixture injected pericapsularly, and physiologic sodium hydrochloride injected intra-articularly into two facet joints. To evaluate the results, three outcome variables were formed: work, subjective, and disability outcome. The inappropriate signs (IAS) recorded before injections had the best predictability for a good outcome. The mode of injection or duration of symptoms had no significance as a predictor. It was concluded that the outcome after facet joint injection depends on the patient's biopsychosocial chances of self-facilitated improvement. If abnormal illness behavior and distress are found, it helps to estimate the response for treatment and to choose a realistic method of treatment.

Adult↗

PubMed1990

Improved visualization of posterior fossa with clivoaxial CT scanning plane.

Eighteen patients clinically suspected of having acoustic neurinoma were studied in both orbitomeatal and clivoaxial (CA) (the plane perpendicular to clivus) CT scanning planes during the same sessions. On the CA cuts there were highly significantly less (p less than 0.001) artifacts. Also, the tentorium was highly significantly (p less than 0.001) better visualized on the CA cuts. CA cuts could be recommended in cases when artifacts disturb the diagnostics of posterior fossa pathology or when detailed topographic information about pathologic anatomy round the tentorium is needed.

Adult↗

PubMed1989

Magnetic resonance imaging of tibial shaft fracture repair.

Magnetic resonance imaging (MRI) of normal fracture repair was evaluated in six randomly chosen adult patients with solitary, closed fractures of the tibial shaft by obtaining serial MRI scans until union of the fracture. The mean time to union was 14.3 weeks. Ultralow-field 0.02-Tesla magnet equipment was used. The MRI scans showed a characteristic pattern of events common for all the patients studied and compatible with the recognized histomorphology of fracture repair. The intramedullary cavity demonstrated a marked decrease in the signal intensity. In the soft tissues surrounding the fracture the initially evenly high signal intensity gradually developed a granular appearance with embedded low-intensity nodules. These nodules corresponded to the first areas to become mineralized, as could be seen on plain radiographs several weeks later. The question of whether MRI renders it possible to predict delayed union calls for continued investigations.

Adult↗

PubMed1989

Low-back pain after lumbar fusion. Surgical and computed tomographic analysis.

Forty-eight patients with persistent pain after lumbar fusion were examined using computed tomography (CT). A total of 157 findings were observed, obviously with greatly varying significance. The main lesions were fragmentation of the fusion mass (16 patients), hair-line pseudarthrosis (9 patients), and spinal stenoses (8 patients). These were also the most frequent indications for reoperation in 20 patients. If the indication for reoperation was fragmentation, hair-line pseudarthrosis, or central spinal stenosis, the results were usually good during a follow-up period that ranged from 6 months to 4 years. At reoperation, 21 of 27 main lesions detected by CT were confirmed; six CT findings were partially or totally incorrect. However, we consider CT to be the best method for examining these problematic patients, but emphasize the choice of relevant CT diagnoses.

Adolescent↗

PubMed1989

Validity of clinical tests in the diagnosis of root compression in cervical disc disease.

The purpose of this study was to test the validity of three clinical tests (the neck compression, the axial manual traction, and the shoulder abduction test) in the diagnosis of root compression in 43 patients with cervical disc disease. The validity was investigated regarding radicular pain, neurologic signs, and root compression signs in myelography. All tests were highly specific for the validity parameters. However, the sensitivity was low; it ranged from 26 to 50% for the three single validity parameters in roots C6-8, and from 40 to 64% for combined neurologic and radiologic signs. It is concluded that, despite low sensitivity, these tests are a valuable aid in the clinical examination of a patient with neck and arm pain.

Adult↗

PubMed1989

Lumbar facet joint syndrome. A randomised clinical trial.

A group of 109 patients with unilateral low back pain for over three months were randomised to receive one of three types of injection treatment: cortisone and local anaesthetic injected into two facet joints (28), the same mixture around two facet joints (39), or physiological saline into two facet joints (42). The effect of the treatment was evaluated in relation to work attendance, pain, disability and movements of the lumbar spine. Patients were examined one hour and two and six weeks after treatment and also completed a questionnaire after three months. A significant improvement was observed in work attendance, pain and disability scores, but this was independent of the treatment given and movements of the lumbar spine were not improved. Of the 70 patients with initial pain relief after injection, 36% reported persisting benefit at the three month follow-up, independent of the mode of treatment given. We conclude that facet joint injection is a non-specific method of treatment and the good results depend on a tendency to spontaneous regression and to the psychosocial aspects of back pain.

Adult↗

PubMed1989

Allogeneic grafts for bone tumor. 21 cases of osteoarticular and segmental grafts.

We treated 21 aggressive and malignant bone tumors by wide resection and replacement with deep-frozen osteoarticular and segmental (intercalary and block) allografts. Radiologic and histologic studies showed a gradual accretion of new bone on the graft trabeculae, sometimes with total creeping substitution. Substantial resorption of grafted condylar bone occurred in 3 of 14 cases. One of them ended with arthrodesis; in the other 2 the result after augmentation autografts was fair. Radiographically, a gradual joint surface destruction was observed in all the osteoarticular grafts after 5 years, not correlating with joint function, however. Biopsies showed some cartilage regeneration. Each patient underwent, on an average, two operations. Function after osteoarticular grafts at 3-16 years was excellent in 1 case, good in 4, fair in 6, and poor in 1 case; 2 cases were too recent for evaluation. Function 3-12 years after segmental grafts was excellent in 3 cases and poor in 3 cases (1 amputation due to nonunion, 1 amputation due to recurrence, and 1 prosthetic replacement due to recurrence); 1 case was too recent for evaluation. We conclude that an allograft is an acceptable alternative in the reconstruction of large tumor defects. However, it still presents unsolved immunologic and preservation problems, which make the prognosis guarded.

Adolescent↗