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Biomedical subjects

M Jacobsson

Publications and source records attributed to M Jacobsson.

At least 19 recordsLinked to original sources
PubMed2000

A microradiographic investigation of cancellous bone healing after irradiation and hyperbaric oxygenation: a rabbit study.

PURPOSE: To analyze the effect of irradiation on cancellous bone healing at different times after irradiation and to study if hyperbaric oxygen therapy (HBO) would affect the bone healing capacity, when delivered directly after irradiation. METHODS AND MATERIALS: Rabbits were given a single dose of 15 Gy (60)Co radiation to one hind leg, the other hind leg serving as control. A standardized defect through the femoral metaphysis of the rabbits was created by a trephine drill biopsy at different times after irradiation. New bone formation in the defect was evaluated by a new biopsy through the previous defect after a healing time of 8 weeks. The mineral contents of the biopsies were analyzed by microradiography and microdensitometry. RESULTS: There was a large variation in the bone-forming capacity expressed as bone mineral content between the animals. No statistically significant differences could be detected regarding the effect of irradiation, HBO, or delayed surgery. Qualitative histology revealed more pronounced inflammation, fibrosis, and bone resorption in the irradiated bone. CONCLUSIONS: No definite conclusions can be drawn from the results of this study, however it might be hypothesized that cancellous bone recovers faster than cortical bone from radiation trauma.

Animals↗
PubMed2000

A histomorphometric and biomechanical study of the effect of delayed titanium implant placement in irradiated rabbit bone.

BACKGROUND: The time interval from irradiation to implant surgery has been considered an impact factor for implant integration in irradiated bone and the importance of a long interval between the radiation trauma and reconstructive bone surgery has been suggested. PURPOSE: The present study was undertaken to histomorphometrically and biomechanically analyze the effect of delayed implant placement on bone healing around titanium implants in irradiated bone. MATERIALS AND METHODS: Rabbits were given a single dose of 15 Gy Cobalt60 radiation to one hind leg, the other hind leg serving as a control. Titanium screws were inserted into the femur and tibia directly and at 12 weeks and 52 weeks after irradiation. The implants were evaluated after a healing time of 8 weeks. The torques necessary for removal of the implants were measured. Histomorphometry with respect to bone-metal contact and amount of bone surrounding the implants was performed. RESULTS: The biomechanical force necessary to unscrew the titanium implants in the irradiated bone was significantly increased after a resting period of 1 year between irradiation and implant placement, compared to direct implant placement. The histomorphometric evaluation showed an improvement of bone healing around the implants in the irradiated bone, both after a resting period of 12 weeks and after 1 year compared to direct implant placement. CONCLUSIONS: It is concluded that a relatively long interval between irradiation and reconstructive bone surgery will improve osseointegration of titanium implants in irradiated rabbit bone.

Animals↗
PubMed1998

Gothenburg osseointegrated hip arthroplasty. Experience with a novel type of hip design.

The culmination of more than 10 years of laboratory and clinical research has been the clinical trial of a novel hip arthroplasty for osseointegration. The femoral component of this Gothenburg hip is a neck retaining, threaded fixture with rotational symmetry, produced in commercially pure titanium with a specific surface texture. Proximally, a standard orthopaedic taper trunnion mates with a 28-mm diameter zirconia head that articulates against the acetabular component. The latter is also of textured commercially pure titanium, encapsulating a thick ultra high molecular weight polyethylene liner. Dedicated alignment guides and cutting instruments ensure accurate bone preparation and implant placement. Limited clinical trials commenced in 1992 and expanded to multicenter clinical trials in 1997. Every hip has been monitored with radiostereometry to measure migration to an accuracy of 0.1 mm. All calcar implanted femoral components show excellent function at 4 to 5 years followup, with no migration revealed by radiostereometry.

Animals↗
PubMed1993

The effects of hyperbaric oxygenation on bone-titanium implant interface strength with and without preceding irradiation.

This study investigated the influence of a single 15-Gy dose of irradiation on the capacity of titanium screws to integrate in irradiated bone tissue. The biomechanical force necessary to unscrew the titanium implants 8 weeks after placement was 54% lower for implants in irradiated bone tissue compared to implants in nonirradiated bone tissue. Postirradiation use of hyperbaric oxygen treatment at 2.8 ATA (2-hour daily treatments for 21 days) increased the biomechanical force necessary to unscrew the titanium implants by 44% in irradiated bone and by 22% in nonirradiated bone.

Animals↗
PubMed1992

Tissue-integrated implants in children.

The aim of this study is to present our clinical experience with tissue-integrated extra-oral implants in children. Thirty consecutive cases of children with a total of 59 standard titanium fixtures inserted in the temporal bones and used as bone-anchorage for auricular epistheses (14 cases) and hearing aids (16 cases) were studied. The surgical procedure is performed in two steps and involves an extremely gentle handling of the soft tissue and bone. The patients were followed with regular check-ups for an average of 40 months after hearing aid/prosthesis fitting. The fixture survival rate was 96.6% for the whole group. The hearing aids had a reaction-free skin penetration in 91.67% of the postoperative observations and the prostheses had a reaction-free skin penetration in 75.00% of the postoperative observations. It is concluded that the use of 'osseointegrated', implants in carefully selected cases, in children, appears to be a reliable method for bone anchorage of epistheses and bone conduction hearing aids. A close follow-up and control of this patient category is especially important with respect to the long-term results.

Adolescent↗
PubMed1992

An evaluation of auricular prosthesis using osseointegrated implants.

The purpose of this evaluation is to compare whether retention of auricular prostheses, through utilization of osseointegrated implants rather than by adhesive, provides any improvement in patient acceptance and prosthesis longevity. Forty-seven out of a total of 49 patients having facial prostheses, retained by means of Brånemark fixtures, were surveyed. Ease of retention was noted in 91% of the patients. Satisfaction with the shape of the prosthesis, colour and ease of positioning was 100, 85 and 98% respectively. None of the patients experienced skin irritation under the prosthesis and 94% of them wore their prosthesis daily. Of the 13 patients with previous prosthesis experience, 92% stated improved retention and all of them found ease of positioning and wearing comfort had improved. Durability was better in 62%, unchanged in 23% and worse in 15% of these 13 patients.

Adolescent↗
PubMed1992

A retrospective study of osseointegrated skin-penetrating titanium fixtures used for retaining facial prostheses.

This investigation was conducted to evaluate osseointegrated skin-penetrating facial titanium implants used for anchoring facial prostheses over a 5-year period and to recommend guidelines for the use of osseointegrated implants in the restorative treatment of auricular and orbital defects. The total success rate for implant survival was 95.6% in the auricular defects and 67.2% in the orbital defects. Approximately 10% of the patients will have some skin problems, whereas the remaining 90% will have no or minimal problems. The possibility of achieving osseointegration around an orbital defect is not as good as in the mastoid process. Success criteria for the use of implants in the craniofacial region are given.

Adolescent↗
PubMed1992

Titanium implants in irradiated tissue: benefits from hyperbaric oxygen.

Since the introduction of osseointegrated titanium implants for bone-anchored facial and dental prostheses, an increasing number of irradiated patients are being treated with this technique. Although the number of patients who have had titanium implants after irradiation is limited, available statistics point to a tendency of a higher implant loss frequency as compared with nonirradiated patients. This review discusses factors behind deleterious tissue effects and implant failures from irradiation and points to possibilities to improve the surgical outcome with special reference to hyperbaric oxygen therapy.

Animals↗
PubMed1991

Relationship between insertion torque and removal torque analyzed in fresh temporal bone.

Insertion torque and removal torque of fixtures were measured using human cadaver temporal bone and human living bone. The torque level for fracturing the threads of the bone was also measured. The maximum insertion torque exerted without causing a break in bone threads was 70.0 Ncm in bicortical bone and 50.0 Ncm in unicortical bone. The relationship between insertion torque and removal torque indicated a positive correlation between both sites. However, removal torque was lower than insertion torque in all measurements. The fracture points of bone threads were 77.0 Ncm in bicortical bone and 57.7 Ncm in unicortical bone by mean. Microfractures were observed mainly in the thread bases and were directed upward in the histologic specimens examined.

Aged↗
PubMed1990

Acute otitis media and facial palsy in children.

Two cases of facial palsy in connection with acute otitis media are presented. The patients were 2 months and 2 years old, respectively. In both cases the facial palsy disappeared after treatment with myringotomy and antibiotics. The etiological mechanisms behind and the different approaches to the treatment of facial palsy in children with acute otitis media are discussed.

Acute Disease↗
PubMed1990

Ten years of experience with the Swedish bone-anchored hearing system.

In 1977, a new phase began in hearing rehabilitation of patients with chronic middle and external diseases and atresias. Thus far, these patients have had to rely on conventional bone conduction and air conduction devices that for various reasons give poor rehabilitation. The principle of the new treatment, made possible by the Swedish bone-anchored hearing system, is simple: sound vibrations are directly transmitted to the skull bone via a skin-penetrating titanium implant and then are further transmitted to the cochlea, bypassing the middle ear. The present paper summarizes our results in 147 patients over 10 years, including a total of 6,334 follow-up months. No significant rate of skin infections was observed. In over 93% of the observations, no sign of adverse skin reaction was seen. When herein-suggested indications for treatment with the bone-anchored sound processor HC-200 are followed, the success rate is over 90%. The improved quality of life reported by the patients is a combination of improved quality of sound, improved comfort, and relief from middle ear and ear canal disease occasioned by conventional hearing aids.

Adolescent↗
PubMed1990

Reconstruction of severely resorbed edentulous maxillae using osseointegrated fixtures in immediate autogenous bone grafts.

A surgical technique for rehabilitation of severely resorbed edentulous maxillae using fixed prostheses or overdentures supported by osseointegrated fixtures in immediate autogenous corticocancellous bone grafts from the ilium is described. The results of the first 23 consecutively treated patients are reviewed. The mean observation time was 4.2 years (range 1 to 10 years). A total of 124 fixtures was originally placed into the grafts, supplemented with 16 fixtures inserted later into seven of the jaws. Throughout their observation period, 17 of the patients had continuously stable prostheses. The remaining five had overdentures, and one patient had resorted to a conventional complete denture. After 4 years, 12 of 16 patients had continuously stable prostheses. Corresponding values at 5 years were 7 of 8 patients. Calculated from the date of abutment connection, 82.1% and 81.6% of the original fixtures were clinically stable and radiographically osseointegrated after 4 and 5 years in function, respectively. From the date of fixture placement, the corresponding figures were 75.3% and 73.8%, respectively. The mean marginal bone loss after the first year of prosthesis function was 1.49 mm. The annual marginal bone loss thereafter was about 0.1 mm. The results indicate that this technique is worthwhile for patients with extreme maxillary atrophy and who cannot wear conventional complete dentures.

Adult↗
PubMed1989

Involution of juvenile nasopharyngeal angiofibroma with intracranial extension. A case report with computed tomographic assessment.

In September 1979 the patient, a man born in 1964, noticed pain and swelling of the right cheek in combination with periods of epistaxis. A computed tomographic scan revealed a tumor extending from the middle of the right nasal cavity into the right maxillary antrum and up toward the orbital floor with destruction of the medial and lateral walls of the antrum and continuing into the sphenoid sinus on the right side and dorsal to the pterygoid process up under the base of the skull. Angiography showed arterial supply mainly from the right external carotid artery, but also from the right internal carotid artery and the left external carotid artery. The process was diagnosed as a juvenile nasopharyngeal angiofibroma. In spite of two attempts at resection of the tumor and arterial embolization, the tumor progressed intracranially. Further operative attempts were decided against, and the patient was followed with repeated computed tomographic scans. The tumor eventually became involuted; eight years after the initial diagnosis, there was no evidence of computed tomographic scans of intracranial growth of the tumor.

Adult↗
PubMed1989

Aberrant intratympanic internal carotid artery: a potentially hazardous anomaly.

A case is presented of a 3-year-old girl with no previous history of ear disease or developmental defects who bled profusely upon (right) myringotomy. The haemorrhage could only be stopped with the aid of an ear insert and a nasopharyngeal balloon catheter. The balloon catheter was removed the following day but the girl had to use an ear insert for a total of 76 days following myringotomy because of repeated haemorrhage from the ear. The subsequent investigation using CT and angiography revealed an aberrant internal carotid artery in the middle ear. It is concluded that the one most important factor in the handling of these cases is to be aware of the existence of aberrant internal carotid arteries and to have a high degree of suspicion when encountering any abnormal clinical or radiological findings which might point in the direction of vascular abnormalities. The failure to detect this condition before any surgical intervention on the affected ear can have disastrous consequences. The method of choice in handling these cases is one of avoidance of middle ear manipulation in order not to cause haemorrhage from the aberrant artery.

Carotid Artery, Internal↗
PubMed1989

Patients' attitudes to the bone-anchored hearing aid. Results of a questionnaire study.

A questionnaire constructed to evaluate subjective patient opinions about a new bone-anchored hearing aid was sent to the first 65 patients who underwent this treatment. All 62 patients who were reached responded to the questions formulated according to the critical incident approach. 74% of the patients stated that they were very pleased with what they regarded as an improved sound transmission. 32% of the patients had noticed a qualitative improvement and the same percentage spontaneously commented on their improved cosmetic appearance with the new hearing aid.

Adolescent↗
PubMed1988

Recurrent bone regeneration in titanium implants. Experimental model for determining the healing capacity of bone using quantitative microradiography.

An experimental technique for quantitative assessment of bone repair was tested. The recurrent regeneration capacity of cortical bone was analyzed in consecutive 3 wk periods, using an osseointegrated titanium implant, the Bone Harvest Chamber (BHC), in the proximal tibial metaphysis of the rabbit. The BHC is a divisible implant penetrated by a canal into which newly formed bone tissue will grow during a 3 wk healing period. The newly formed bone tissue may easily be collected (harvested) without the animal being killed. After 3 wk, bone tissue can again be harvested, in principle, indefinitely. Intact harvested specimens were quantified by microradiography-videodensitometry, yielding a total specimen mass in mg aluminium equivalent. This unit correlated very well to a specimen dry weight (r = 0.996) and an average mineralized bone density (r = 0.937). The specimens were also examined by correlative histology. Three weeks after implant insertion, the chambers had become integrated in the bone tissue but the average bone mass varied widely, influenced by the surgical insertion trauma. Six weeks after insertion, the greatest average bone mass was found, indicating an intense ongoing osseointegration. The amount of bone regenerated at later harvests was fairly equal, indicating a stabilization of the implant bed to the repeat stimulus, i.e. harvesting. Bone regeneration differed significantly between animals, but also intraindividual variations, i.e. different amounts of bone formed in the same chamber, were observed.

Animals↗