Impact of a physician-staffed helicopter on a regional trauma system: a prospective, controlled, observational study.

INTRODUCTION: This study aims to compare the trauma system before and after implementing a physician-staffed helicopter emergency medical service (PS-HEMS). Our hypothesis was that PS-HEMS would reduce time from injury to definitive care for severely injured patients. METHODS: This was a prospective, controlled, observational study, involving seven local hospitals and one level I trauma centre using a before and after design. All patients treated by a trauma team within a 5-month period (1 December 2009-30 April 2010) prior to and a 12-month period (1 May 2010-30 April 2011) after implementing a PS-HEMS were included. We compared time from dispatch of the first ground ambulance to arrival in the trauma centre for patients with Injury Severity Score (ISS) > 15. Secondary end points were the proportion of secondary transfers and 30-day mortality. RESULTS: We included 1788 patients, of which 204 had an ISS > 15. The PS-HEMS transported 44 severely injured directly to the trauma centre resulting in a reduction of secondary transfers from 50% before to 34% after implementation (P = 0.04). Median delay for definitive care for severely injured patients was 218 min before and 90 min after implementation (P < 0.01). The 30-day mortality was reduced from 29% (16/56) before to 14% (21/147) after PS-HEMS (P = 0.02). Logistic regression showed PS-HEMS had an odds ratio (OR) for survival of 6.9 compared with ground transport. CONCLUSIONS: Implementation of a PS-HEMS was associated with significant reduction in time to the trauma centre for severely injured patients. We also observed significantly reduced proportions of secondary transfers and 30-day mortality.

Transfusion of intra-operative autologous whole blood: influence on complement activation and interleukin formation.

BACKGROUND AND OBJECTIVES: Transfusion of autologous whole blood is one available method to reduce the need for allogenic blood transfusion. The objective of this study was to investigate the safety of transfusion of intra-operative autologous whole blood by monitoring plasma concentration of laboratory variables and adverse events after transfusion with the Sangvia(®) system. MATERIALS AND METHODS: The clinical trial was designed as an open, prospective, multi-centre study, and a total of 20 patients undergoing primary hip arthroplasty were included. Systemic blood samples were taken and analysed preoperatively, at transfusion start and end and at 3, 6, 24 and 48 h after the transfusion. RESULTS: Elevated values of complement activation and pro-inflammatory cytokines were seen in the intra-operatively collected blood but the impact on systemic levels were limited with low peak levels, systemic elevations before transfusion and normalization during the study period. Elevated levels of free haemoglobin and potassium were also detected in the intra-operatively collected blood, but systemic values were within reference values after the transfusion. No clinically relevant adverse event occurred during the study. CONCLUSION: Inflammatory mediators and plasma haemoglobin were increased in intra-operatively salvaged and filtered blood compared to circulatory levels. Intra-operative retransfusion of autologous whole blood caused a transient systemic increase that normalized in the early postoperative period. There were no significant adverse events reported in the study. These data suggest that the Sangvia(®) system can be used for intra-operative collection and retransfusion of salvaged blood.

Complement split products and proinflammatory cytokines in intraoperatively salvaged unwashed blood during hip replacement: comparison between heparin-coated and non-heparin-coated autotransfusion systems.

BACKGROUND AND OBJECTIVES: The aim of the present study was to investigate the quality of shed blood collected in a new intraoperative autotransfusion system (Sangvia, AstraTech, Sweden) and to study whether heparin-coated surfaces in the device reduce the production of inflammatory mediators. MATERIAL AND METHODS: The study was randomized and prospective. Twelve total hip arthroplasty patients whose blood was collected with a device having a heparin-coated surface and 12 patients whose blood was collected with a device having a non-heparin-coated surface were included. Venous blood was drawn from the patients preoperatively. Intraoperatively 200 ml salvaged blood was collected and samples were also withdrawn; samples were obtained from the blood bag. RESULTS: Compared to venous blood, elevated concentrations of interleukin 6 (IL-6), IL-8, C3a and polymorphonuclear elastase were found in collected blood. No significant differences in inflammatory mediators were found between the heparin-coated and the non-heparin-coated groups. The median haemoglobin concentration in the salvaged blood was 74 g/l in both groups. Plasma haemoglobin and potassium concentrations were also elevated. There were no significant differences between the groups. CONCLUSION: The present study indicates that the blood salvaged intraoperatively contains elevated levels of complement split product and proinflammatory cytokines and that heparin-coated surfaces of the salvage device do not significantly influence the formation of inflammatory mediators.

Dose-response for bone regeneration after single doses of 60Co irradiation.

The Bone Growth Chamber (BGC) methodology was used to establish a dose-response relationship for regeneration of mature bone tissue after irradiation of 5, 8, 11, 15 and 25 Gy single dose 60Co. The BGC, which is a titanium implant, was inserted in the proximal tibial metaphyses, bilaterally, of a rabbit immediately following local irradiation to one tibia. Each animal thus served as its own control. During a healing period of 4 weeks, the two canals penetrating the implant became filled with more or less newly formed bone. At the end of the healing period, the implants were removed and taken apart and the newly formed bone was collected and its volume measured by microradiography and microdensitometry. It was found that in the dose range of 5 to 8 Gy bone regeneration was reduced by about 20% as compared to non-irradiated controls. Between 8 and 11 Gy, there was a critical range in that a small increase in dose resulted in a greatly reduced bone formation. At 11 Gy and above, the depression in bone formation, as compared to non-irradiated controls, was about 65 to 75%.

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.

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.

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.

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.

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.

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.

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.

A histomorphometric study of bone reactions to titanium implants in irradiated bone and the effect of hyperbaric oxygen treatment.

The present study was undertaken to histomorphometrically analyze early peri-implant bone tissue reactions that occur after radiotherapy and to determine whether hyperbaric oxygen therapy (HBO) affects bone tissue at the microscopic level by altering bone morphology. Twelve rabbits received a single dose (15 Gy) of cobalt60 radiation to one hind leg and the other hind leg served as a control. Titanium screws were placed into the femur and tibia directly after irradiation. Six animals received HBO during the first 4 postoperative weeks. After 8 weeks of follow-up, bone specimens containing the screws were prepared for histomorphometry. Bone-metal contact and the amount of bone in the thread areas and in the mirror areas were measured in a blinded manner. Periosteal bone formation and bone remodeling decreased after irradiation; also after HBO treatment. Hyperbaric oxygen therapy improved bone formation in nonirradiated bone and to some extent also in the irradiated bone. Bone maturation was improved in the HBO animals after irradiation. It was concluded that irradiation reduces the capacity for osseointegration of titanium implants. Hyperbaric oxygen treatment may improve bone formation and especially has positive effects on bone maturation after irradiation.

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.

Bone repair in implant models: a review with emphasis on the harvest chamber for bone regeneration studies.

The vital microscopic chamber is an experimental implant of commercially pure titanium that admits in vivo and in situ observations of bone vascularity and bone remodeling. The bone growth chamber and the bone harvest chamber, in particular, are useful tools for quantifying bone regeneration under the most variable experimental conditions.

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.

Present clinical applications of osseointegrated percutaneous implants.

Altogether, 389 screws of commercially pure titanium have been inserted at various locations in the facial skeleton of 174 patients. The indications for treatment have been stable anchorage of an external hearing aid or a facial episthesis, in the latter case to restore the facial contours after congenital disorders or status after trauma or cancer surgery. All implants have been inserted in a two-stage procedure, the first being anchorage of the titanium elements in the bone, the second, minimally 3 months later, being establishment of a permanent skin penetration. The outcome of every inserted implant has been analyzed. Only six implants failed to become integrated in bone and had to be removed. Five of these failures occurred in previously irradiated bone, where the success rate was estimated to 85.3 percent. In nonirradiated bone, 354 of 355 inserted implants became osseointegrated, i.e., anchored in bone in a stable manner. The soft tissues were without any adverse reactions in 92 percent of the 951 clinical observations, whereas potentially serious skin complications were observed in only 2.8 percent. Presently, the longest clinical follow-up is 8 years, and 37 implants have been followed for more than 5 years. We believe that this clinical material is the first in which an uneventful bone anchorage and skin penetration have been demonstrated in consecutively operated upon clinical cases. The implants used for anchoring an external hearing aid were also successful in the sense that the patients gained 15 dB (average) in hearing threshold and showed a significantly improved discrimination score. The implants inserted to hold facial epistheses resulted in considerably improved retention and a good cosmetic outcome for the patients.

Short- and long-term effects of irradiation on bone regeneration.

The aim of the present study is to quantify bone-regenerative capacity directly and 1 year after administration of 15 Gy 60Co irradiation. A titanium implant, the bone growth chamber, which in nonirradiated cases becomes filled with newly formed bone over a 4-week period, was inserted into each tibial metaphysis of 20 rabbits. In 10 animals the chambers were installed directly after irradiation, while in 10 other rabbits the implants were installed 1 year after the 60Co trauma. In both groups the bone-forming capacity on the irradiated side was compared to that of the contralateral, nonirradiated, control tibia. The amount of bone formed was determined by microradiography and microdensitometry. It was found that bone regeneration was depressed by 70.9 percent within a 4-week period after irradiation. At a follow-up of 1 year, the average depression of bone-forming capacity was only 28.9 percent. This means a recovery by a factor of almost 2.5. The clinical implications of these findings are discussed.

Integration of titanium implants in irradiated bone. Histologic and clinical study.

Nine patients who had undergone combined surgical and radiologic treatment for malignant tumors had skin-penetrating titanium implants inserted in the bone tissue in the treated region at various time intervals after irradiation. The absorbed dose to the implant region varied between 25 and 86 Gy normalized to five fractions of 2.0 Gy/wk, according to the cumulative radiation effect formula. The time interval between irradiation and fixture insertion varied from 9 months to 37 years. Of the 35 fixtures installed, only five were lost because of lack of osseointegration. The follow-up time from implant insertion ranged from 15 to 44 months.

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.

Juvenile nasopharyngeal angiofibroma. A report of eighteen cases.

Juvenile nasopharyngeal angiofibroma is a disease afflicting mainly adolescent males. The lesion is benign but characterized by local aggressive growth. In advanced cases the tumour may extend intracranially. In this study 18 cases of juvenile nasopharyngeal angiofibroma were investigated. Tumour extension was assessed with the use of angiograms and CT and the individual cases staged in four different categories on the basis of tumour extension. Two cases were staged as I (tumour confined to the nasopharynx), 7 cases as II (tumour extending into nasal cavity and/or sphenoid sinus), 8 as III (tumour extending into one or more of the following: antrum, ethmoid sinus, pterygomaxillary and infratemporal fossae, orbit and/or cheek) and one as IV (tumour extending into the cranial cavity). Preoperative arterial embolization was performed in 8 cases. All patients underwent surgery; none received irradiation. The follow-up period was 6 yrs 4 mo (6 months-17 years). In one case of intracranial extension, tumour recurrence occurred. It is concluded that with the aid of CT and arteriograms to evaluate the extension of the tumour and preoperative embolization, this lesion can be cured in the vast majority of cases, with surgery as the method of choice.