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Biomedical subjects

B Vällfors

Publications and source records attributed to B Vällfors.

14 recordsLinked to original sources
PubMed1991

Repositioning of craniofacial tumorous bone after autoclaving.

Thirteen bone tumours that were invading the craniofacial skeleton were operated on by intracranial procedures. The resected tumorous bone was autoclaved and put back. Follow up of no less than one year included 122mTc scanning, computed tomography, radiography, bone biopsy and clinical examination. In every case, when rigidly fixed, most of the autoclaved bone was gradually revitalised by invading new and normal bone. We conclude that autoclaved bone will be replaced by normal bone, and that the present technique is justified for reconstruction of complicated structures or large areas of bone after operations for tumours invading the craniofacial skeleton.

Adolescent↗
PubMed1991

Studies on coagulation and the development of an automatic computerized bipolar coagulator. Technical note.

A new computerized bipolar coagulator is described in which tissue heating is switched off automatically when adequate vessel occlusion has been achieved, thus preventing overheating, undue tissue damage, cutting, and sticking of the forceps. Experiments with radiofrequency (rf) heating of albumin or arteries revealed an impedance minimum at the moment of coagulation. The attainment of this impedance minimum is transmitted electronically via a microprocessor to the coagulator, which automatically shuts off the rf energy supply. In experiments, adequate artery strength and avoidance of the drawbacks of conventional coagulation methods were achieved when rf heating was shut off soon after the impedance minimum was reached. Neither irrigation for cooling nor cleaning of the forceps tips was necessary. Electronic feedback through the same cables as used for coagulation enabled the use of conventional bipolar cables and forceps. The bipolar coagulator described can also be used for conventional bipolar coagulation under visual control. The microcomputer enables: 1) automatic coagulation cycles that start when tissue is picked up in the forceps and stop automatically on completion of the seal; 2) the change of power setting from a pedal and activation of automatic cycles by the pedal as described above or surgeon-controlled coagulation, which facilitates the use of alternative debridement with inactive forceps; 3) cable testing; and 4) negligible disturbance of the intraoperative monitoring equipment.

Animals↗
PubMed1986

Craniofacial surgery for trauma.

Craniofacial surgical techniques have yielded as an important spin-off better methods of treating severe craniofacial trauma. In this paper surgical techniques are discussed. It was concluded that the most important factors for successful reconstruction after craniofacial trauma is to do as much as possible the first time, to obtain wide exposure, ensure rigid fixation of bone pieces and grafts and to make use of a work bench procedure where bone fragments are assembled on a side table for subsequent reattachment to the head.

Adult↗
PubMed1986

The craniofacial approach to trauma.

Craniofacial surgical techniques have yielded better methods of treating severe craniofacial trauma. In this paper surgical techniques are discussed in principle and specifically presented through case reports. We conclude that the most important factors for successful reconstruction after craniofacial trauma are to do as much as possible the first time, to obtain wide exposure, to ensure rigid fixation of bone pieces and grafts, and to make use of a workbench procedure where bone fragments are assembled on a side table for subsequent reattachment to the head.

Adult↗
PubMed1986

Facial disassembly for tumor resection.

A standardized method of surgical dismantelling of the face for access to the periorbital area is described in detail. Its use in 11 patients with periorbital tumors is described and illustrated by selected case reports. It was concluded that many tumors in the periorbital area that previously were considered inoperable with craniofacial disassembling techniques can be adequately treated without sacrificing eyes or mutilating the face.

Adult↗
PubMed1985

Influence of ketanserin on 5-hydroxytryptamine-induced cerebrovascular spasm in the cat.

In an experimental cat model the leptomeningeal vasculature was studied by a vital microscopic brain window technique. The brain window was connected to a thermostat-regulated pool of Elliot's solution. By air-drying (10 min) of the arachnoid mesothelium access for drugs, applied into the pool, was established to the adventitia of the leptomeningeal vasculature. Application of 5-hydroxytryptamine (5-HT) (10(-6)-10(-4) M) caused dose-dependent contractile responses (morphometry of outer vessel diameter) of both arteries and veins of three different sizes (large, 200-300 microns; medium, 50-150 microns; small, 30-50 microns). A well-reproducible contractile response was obtained at challenge with 5-HT (10(-4) M) from the various vascular beds with most pronounced effects on the arterial side. If the animals were pretreated with peripheral blockade of serotonergic (5-HT2) receptors (ketanserin 0.3 mg/kg i.v.), challenge with 5-HT (10(-4) M) elicited no significant vascular responses on either the arterial or venous sides. Vital microscopy further visualized capillary beds after ketanserin pretreatment that were not seen under control conditions.

Animals↗
PubMed1985

Acute, subacute and chronic low back pain: clinical symptoms, absenteeism and working environment.

In this study the relationship between low back pain and the following factors was studied: Clinical findings, frequency and duration of absenteeism, social situation, psychosomatic and psychological factors and the working environment. The sample studied included 220 persons (participation frequency 86%) between the ages of 16-65 who had either acutely declared themselves unable to work because of low back pain (acute patients, n = 50) or who had been ill because of low back pain for one month (subacute patients, n = 50) or for three months (chronic patients, n = 70). A control group (n = 50) consisting of persons who had not been absent at all from work the last year was also included. Information regarding the participants' socio-economic situation, previous and present illnesses, further sick-listing during the one year follow-up period and the duration of absenteeism was obtained from the records of the Department of Health Insurance. The median age for men (68%) in the four different groups was 46, 46, 46 and 48.5, respectively. The corresponding figures for women were 50, 33, 33 and 49 years. Twenty percent were of foreign extraction. The proportion of foreigners in the group of non-participants (n=33) was higher (39%) and in this group there was a significantly greater frequency of previous episodes of ill health of short duration (less than or equal to 7 days + no certificate of ill health). Despite a careful clinical examination it was not possible to find any objective signs amongst 51% (86) of the patients. These patients exhibited normal motion of the back, normal musculature, no signs of neurologic involvement, negative straight-leg-raising test, no fixed painful position and no pain during percussion or palpation despite the fact they had subjective symptoms. The proportion of patients without objective findings increased with increased duration of absenteeism. Forty percent of the acute back patients displayed no objective findings. The corresponding figures for the subacute and chronic back patient groups were 34% and 70%, respectively. In the group without objective findings but with chronic pain (greater than 3 months) there was an increased frequency of Waddell's non-organic signs compared with the group with objective findings. Psychological and social problems increased with increasing duration of absenteeism. There were significantly more patients with psychiatric illness, signs of alcoholism and early retirement in the three months group compared to the remaining groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Absenteeism↗
PubMed1979

Modified suction system for neurosurgery.

A new system providing suction for neurosurgical operations is presented. It is designed so that the amount of suction is readily controllable and provides adequate suction for the removal of fluid and blood clots without damage to the nervous tissue. The device also allows the surgeon an unrestricted view of the operative field.

Neurosurgery↗
PubMed1976

Optimal suction system for dissection work in surgery.

A new system for improved suction in surgical dissection work is presented, in which the suction tube end has slits. The air suction capacity of the pump is 30 litres a minute, and the maximal vacuum pressure in the systems is limited to -0.3 at by means of a membrane pressure regulator. This system allows a continuous atraumatic suction with adequate suction capacity and convenient operation.

Dissection↗