Vascular endothelial growth factor inhibits bone morphogenetic protein 2 expression in rat mesenchymal stem cells

INTRODUCTION

While several studies report that bone morphogenetic proteins (BMPs) and vascular endothelial growth factor (VEGF) can act synergistically to improve bone tissue engineering, others suggest that VEGF inhibits osteogenesis. The purpose of these experiments was therefore to evaluate the effect of dual transfection of these growth factors and potential mechanisms of interaction on gene expression and osteogenesis in vitro and in vivo.

METHODS

Marrow-derived mesenchymal stem cells (MSCs) were exposed to recombinant VEGF protein or transfected with adenoviruses encoding BMP2, VEGF, or LacZ in a variety of ratios. Alterations in gene and protein expression in vitro as well as bone formation in vivo were assessed.

RESULTS

MSC exposure to AdV-VEGF or recombinant VEGF inhibited BMP2 mRNA expression, protein production, and MSC differentiation. Coculture experiments revealed that BMP2 suppression occurs through both an autocrine and a paracrine mechanism, occurring at the transcriptional level. Compared to controls, cotransfection of VEGF and BMP2 transgenes prevented ectopic bone formation in vivo.

CONCLUSION

VEGF is a potent inhibitor of BMP2 expression in MSCs, and supplementation or overexpression of VEGF inhibits osteogenesis in vitro and ectopic bone formation in vivo. Strategies to utilize MSCs in bone tissue engineering therefore require careful optimization and precise delivery of growth factors for maximal bone formation.

Sagittal synostosis: I. Preoperative morphology of the skull

The aim of this study was to characterise the preoperative morphology of the skull in sagittal synostosis in an objective and quantified way. The shapes of the skulls of 105 patients with isolated premature synostosis of the sagittal suture (SS group) were studied and compared with those of a control group of 72 children with unilateral incomplete cleft lip (UICL). A standardised radiocephalometric technique was used to obtain the images. A modification of a method developed by Kreiborg was used to analyse the radiocephalograms, which included the digitisation of 88 landmarks in the calvaria, skull base, and orbit (42 in the lateral and 46 in the frontal projections), the production of plots of mean shape for each group, and the intergroup comparison of a series of 81 variables (linear distance between selected landmarks, and angles defined by groups of three landmarks). Data from a subgroup of 66 patients aged 5 to 8 months were further compared to age-matched normative data in terms of seven angular and linear calvarial, cranial base and orbital variables. In a comparative analysis of the mean lateral plots, the foreheads of the study group (SS) had a more pronounced anterior slope and were also more convex. The vertex area was located more anteriorly, and was less convex. The occipital curvature was more prominent. Analysis of the mean frontal plots revealed a lack in convexity and lateral projection of the upper parietal regions, as well as a lower location of the line of maximum skull width. Comparison of the mean values of an SS subgroup to age-matched normative data showed a longer (p<0.001) and narrower skull (p<0.001) and a greater interorbital distance (p<0.001). The cranial base angle, the sella to nasion, and sella to basion lengths did not differ significantly. Sagittal synostosis is characterised by an extensive deformity of the cranial vault, with an essentially normal cranial base. The widened interorbital distance is probably related to compensatory metopic hyperactivity.

SPRING-MEDIATED CRANIOPLASTY COMPARED WITH THE MODIFIED PI-PLASTY FOR SAGITTAL SYNOSTOSIS

The aim of this study was to compare the safety, morphological outcome, and degree of parental satisfaction of the new spring-mediated cranioplasty with those of the modified pi-plasty in the management of sagittal synostosis. Ten patients with non-syndromic sagittal synostosis treated with the spring-mediated cranioplasty were followed prospectively. A control group of 10 sex-matched patients operated on with the modified pi-plasty procedure was chosen. Cephalometric radiographs were obtained preoperatively and postoperatively at 1 year of age. Cephalic index, axial width ratio, length ratio, width ratio and height ratio were used as objective measures of outcome. Parents were sent a questionnaire to obtain a subjective aesthetic assessment of outcome. Significantly less blood replacement was required (p = 0.003), and shorter duration of postoperative anaesthesia (p = 0.030) and postoperative hospital stay (p = 0.013) were found in the spring-mediated cranioplasty group. There were no complications or deaths in either group. Also significant was the inter-group difference in the postoperative change in the height ratio (p = 0.030), the most change being seen in the spring group. The change in the subjective parental aesthetic evaluation of skull shape was significant in both groups. In conclusion, the spring-mediated procedure was morphologically more effective than the modified pi-plasty procedure in the management of sagittal synostosis with the additional benefits of less blood transfusion needed and shorter duration of hospital stay.

Sagittal synostosis: II. Cranial morphology and growth after the modified pi-plasty

The aim of this study was to characterise the postoperative cranial growth and morphology after a modified pi-plasty for sagittal synostosis. The shape of the skull of 82 patients with isolated premature synostosis of the sagittal suture (SS group) operated on with a modified pi-plasty was studied longitudinally. Forty-five children with unilateral incomplete cleft lip (UICL), evaluated longitudinally at the ages of 2.4 and 23.2 months were used as controls. A standardised radiocephalometric technique was used for image acquisition. The radiocephalograms were analysed using a modification of a method developed by Kreiborg, which included the digitisation of 89 landmarks of the calvaria, cranial base, and orbit (43 in the lateral and 46 in the frontal projections), the production of mean shape plots for each group, and the intergroup comparison of a series of 78 variables (linear distance between selected landmarks, and angles defined by groups of three landmarks). Paired and unpaired t tests were used to assess the differences between the variables studied. These were accepted as significant for values of p<0.01 and were presented as coloured segments or areas in the respective plots. In a comparative analysis with the mean UICL lateral plots, the mean preoperative lateral plots of the study group (SS) showed that the anterior slope of the forehead was more pronounced and it was also more convex. The vertex area was located more anteriorly and was less convex. The occipital curvature was more prominent. Comparison of the mean frontal plots showed a deficiency in convexity and lateral projection of the upper parietal regions, and the line of maximum skull width was lower. The postoperative mean lateral plots of the study group showed a correction of the exaggerated anterior inclination of the forehead and a reduction of the abnormal occipital convexity. However, there was little change in the vertex region and it remained flatter than in the control group. In the mean frontal plots, the increase in convexity and in the lateral projection of the upper parietal areas led to a shape that was similar to that of the UICL group. The mean (SD) cephalic index changed from 64.9% (1.8%) to 71.4% (3.5%) (p<0.001). The longitudinal comparison between the mean postoperative plots at 3 and 5 years of age showed that there had been little change in cranial shape. In conclusion, after a modified pi-plasty for sagittal synostosis, significant objective changes in cranial shape towards normality were produced. The postoperative profile cranial shape was improved except in the vertex area, which remained flatter than normal. In the frontal projection an almost normal shape was obtained. The postoperative cranial shape obtained at 3 years of age had remained stable at the age of 5 years.

Calvarial bone healing under spring distension at continuous forces

The aim of the present study was to evaluate in young animals the dynamics of calvarial bone healing when exposing a bone defect to continuous forces for up to 13 weeks. Six-week-old rabbits after a sagittal suture strip craniectomy were randomized for either of the following protocols: (1) no spring was applied (n = 7); (2) a titanium-molybdenum alloy (TMA) lower-force spring was inserted across the craniectomy gap (n = 9); (3) a stainless steel (SS) higher-force spring was applied (n = 8), or (4) sham operation (n = 8). Results showed that the surgically created calvarial bone gap was after 3 weeks kept widened both when a spring of lower force (TMA) and when a spring exerting a higher force (SS) was applied. At 6 weeks, none of the rabbits of the spring-exposed (2 and 3) groups had any bone bridging the gap, while bone bridging was visible in animals of the 2 groups (1 and 4) lacking springs. Strikingly enough, in both spring-treated groups, the surgically created defect was still after 13 weeks incompletely bridged by bone, interposed by connective tissue, most evidently in those exposed to higher forces (SS). In contrast, a normal sagittal suture enclosed by lamellar bone was seen in both the sham and the strip groups. We conclude that exposing a surgically created calvarial bone defect to continuous mechanical forces delayed the bridging of the bone defect by at least 13 weeks, even if the force exerted by either spring was very low. In any case, when a higher force (SS group) was applied, the bone reunion was efficiently prevented. No side effects were recognized.

Triage and initial treatment of burns in the Gothenburg fire disaster 1998. On-call plastic surgeons' experiences and lessons learned

Just before midnight on the 29 October 1998 the on-call plastic surgeons were alarmed because of a fire accident thought to involve a few burned patients. Quite soon the information suggested an in-door fire disaster in which many of the 400 young people visiting a disco were caught by a rapidly spreading fire. A cross-sectional survey of the resulting overload, triage and initial treatment of burns was analysed. Two-hundred and thirteen patients were transported to the four hospitals in Gothenburg area and a total of 150 were admitted as inpatients, 73 to Sahlgrenska University Hospital. The initial organisation at the scene of the fire was seriously inadequate because of incorrect information about the number of casualties. As there was no triage officer the principle of "scoop and run" was practised, placing the major burden on the receiving hospitals. The emergency disaster plan in our hospital was not launched, because of misinformation and lack of communication. Early documentation in emergency case books was incomplete as the whole organisation was overloaded. Intubation or tracheostomy and escharotomy at the intensive care unit were not delayed. Triage for transportation to burns units was adequate.

Orbital fractures in craniofacial trauma in Göteborg: trauma scoring, operative techniques, and outcome

In the 10-year period 1986-1996, 85 patients were admitted to our unit with craniofacial injuries, 56 of whom had orbital fractures. These were studied with respect to the type of injury, type and location of fracture, presence of ocular and intracranial injury, and associated injuries to the head and body, as well as operative techniques used. Both the patient's and the surgeon's opinion on the aesthetic result were noted. The patients were also given a questionnaire about their quality of life after the injury. Road traffic crashes accounted for 31 (55%) of the injuries, falls for 9 (15%), and horse-riding for 6 (11%). The Injury Severity Score (ISS) ranged from 4 to 41 (mean 18). Twelve also had eye injuries, which resulted in complete blindness in one eye in 4 (7%). Thirty patients had 41 neurological injuries (54%), frontal contusions being the most frequent diagnosis (n = 15). Exact repositioning with rigid fixation included bone grafting to the orbit in 11 patients, and the dominating bone graft was split calvarium (n = 5). Forty-two patients completed a questionnaire, 26 of whom (64%) had no aesthetic complaints. Seven of the 42 were too disabled to work one year after the injury. Re-exploration was infrequent and the aesthetic outcome, both in the surgeon's and the patient's opinion, was good. However, the older the patient, the worse the outcome.

Fire disaster in Gothenburg 1998--surgical treatment of burns

A tragic in-door fire disaster took place on 29 October 1998 at a discotheque in Gothenburg, Sweden. Nearly 400 youths attending a Halloween party were inside the building when the fire started, killing 61 people and injuring another 213 persons. A total of 154 youths were admitted to hospital care. Twenty-three patients requiring primary reconstructive burn surgery were followed and their records from the different burn units were examined. Total body surface area (TBSA), burn depth, surgical treatment, hospital stay, and complications were studied. In contrast to what is normally encountered in burn patients, well circumscribed predominantly full-thickness burns covering 1-40% TBSA were observed while partial-thickness burns only comprised 1-7% TBSA. Exposed bone was seen in 10 out of 23 patients. Escharotomies were performed in 11 patients, in six of whom that fasciotomies had to be performed. Primary excisions and skin grafting were performed in 22 patients. Five patients acquired amputations. Eight patients required local flaps and two had free flap coverage. Thoracic surgery was performed in one patient due to endocarditis. Severe infections occurred in eight patients. Hospital stay varied between 21 and 164 days.

Dynamic spring-mediated cranioplasty in a rabbit model

Since the beginning of craniofacial surgery, there has been an ongoing search for surgical techniques to enhance outcome while, at the same time, decreasing the invasiveness of the surgical treatment of craniofacial deformities. The purpose of this study was to test a recently reported minimally invasive treatment modality, the dynamic spring, in a rabbit calvarial model for efficacy and safety. Specifically, the results of spring cranioplasty on skull growth, the underlying brain, and adjacent bone were to be assessed. The study population consisted of 36 7-week-old New Zealand white rabbits. The rabbits were divided into four treatment groups (9 rabbits each): control, sham surgery, stainless steel springs, and memory metal springs. Postoperative analysis included weekly radiographs to evaluate movement of amalgam markers placed at standardized locations. Additionally, 16 rabbits (4 from each group) were killed at 14 days after surgery, and postmortem histological analysis was done. The remaining rabbits were followed until they were adults and were then killed and similarly analyzed. No morbidity or mortality occurred in the immediate perioperative period secondary to the surgery. Postmortem histological analysis of all study animals revealed no intracranial, subcutaneous, or skin infections and no technical complications related to the surgery. Statistical analysis using ANOVA and pair-wise comparisons between treatment groups revealed a statistically significant difference (P < 0.05) between the marker movement in the spring groups versus the sham and control groups. There were no significant differences between the sham and control groups or between the two spring groups. In conclusion, this study confirms the efficacy and safety of the dynamic spring in a rabbit model.

Calvarial bone distraction with a contractile bioresorbable polymer

The aim of the present study was to evaluate the possibility of mobilizing calvarial bone with a fully implantable and bioresorbable device. The animal model used was the New Zealand white rabbit (n = 12). An island bone flap attached to the dura mater was created in the parietal region and amalgam markers were placed in this bone flap and in the ipsilateral frontal bone. In one group of six rabbits (group 1), a specially processed contractile 70L/30D,L polylactic acid plate, 15 x 6 x 0.6 mm, was attached to the island flap by one extremity, and to the fixed ipsilateral frontal bone by the other. In group 2 (control), no plate was added. Bone marker movement was followed with serial radiography. In group 1, there was a progressive reduction in mean marker distance over the first 48 hours, and stability thereafter. In group 2 (control), mean marker distance remained stable until the second postoperative week, after which time there was a slight increase until the end of the experimental period. At 4 weeks, the mean marker separation differed significantly between group 1 (mean, -3.62 mm; SD, 0.79 mm) and group 2 (mean, 0.34 mm; SD, 0.14 mm; p <0.001). In conclusion, a totally implantable and bioresorbable device was successfully used to mobilize calvarial bone. Polymer contractility will likely constitute the basis of a new generation of bioresorbable distractors for use in craniofacial surgery.

The lateral thoracodorsal flap in breast reconstruction: a long-term follow up study

Fifty-four patients were studied a mean of five years after their breasts had been reconstructed between 1984 and 1990 using the lateral thoracodorsal (LTD) flap in combination with either a thin shell, non-low-bleed (n = 35) or a thick shell, low bleed (n = 19) silicone gel implant. The rate of capsular contracture (Baker III-IV) was 11% in the first group and 10% in the second according to a modified Baker classification. Open capsulotomy was common in both groups of patients (15/35 in the first group and 13/19 in the second). Investigation by applanation tonometry of the capsular contracture agreed with the modified Baker classification. The cosmetic results were evaluated clinically and from photographs. Best scores were recorded for scars and ptosis in both evaluations. There were no significant differences between the general cosmetic results in the two groups. The patients graded their estimations of the final outcome of their breast reconstruction on a 10-point visual analogue scale (VAS); the mean for the first group was 8.7 and for the second 9.2. None of the patients regretted her operation and they would all recommend the procedure to another patient.

Expander elements in craniofacial surgery: an experimental study in rabbits

With the inception of craniofacial surgery elaborate surgical procedures were introduced for the treatment of craniosynostosis. Recently the use of implantable springs to aid simple strip craniectomies for these conditions has been described. Having shown the feasibility of using springs for dynamic skull reshaping, several questions remain to be answered, all of them about how to control the spring action clinically. One of the most important questions concerns force. The purpose of this study was to evaluate experimentally the effect of two springs of different strengths on the growth of rabbit calvaria after strip craniectomy. Thirty-two 6-week-old rabbits were randomised into one of four groups: sham-operation where only amalgam markers were inserted after subperiostal dissection; strip craniectomy of the sagittal suture, no expansion; strip craniectomy of the sagittal suture and insertion of an expander element made of titanium molybdenum alloy (TMA); and strip craniectomy sagittal suture and insertion of an expander element made of stainless steel (SS). SS springs delivered a range of forces from 2.42-2.18 N, whereas the TMA expander elements delivered a range from 1.39-1.09 N. The parietal bone marker separation after 12 weeks was 4.9 mm in the TMA group and 7.4 mm in the SS group. This resulted in a significant increase of the calvarian height compared with control groups. Histological examination showed intramembranous bone formation in the bone gap in all groups.

Long-term follow-up of dynamic cranioplasty for brachycephaly--non-syndromal bicoronal synostosis

We followed up 10 patients whose non-syndromal bicoronal synostosis had been operated on with a dynamic cranioplasty technique developed by this craniofacial unit in 1992. With this technique, the growth of the brain is redirected in an anteroposterior direction as wire-mediated compression and restraint are exerted on the transverse and vertical dimensions of the skull. The mean operating time was 160 minutes (range 120-275) and mean stay in the intensive care unit was 36 hours (range 23-58). There was no operative mortality and few complications. The surgical results were assessed objectively by analysis of cephalometric tracings. The mean (SD) cephalic index was 87.6 (4.9) preoperatively and 77.7 (1.8) postoperatively (p = 0.001). The modified Whitaker scale was used as a subjective outcome measurement, and nine patients were classified as Whitaker grade 1 (no additional surgery). One patient required additional intracranial surgery. A questionnaire was sent to all families to obtain an additional subjective measurement of outcome. Parents' satisfaction was high. We conclude that dynamic cranioplasty is a safe and efficient operation for treatment of brachycephaly.

Dynamic cranioplasty for brachycephaly in Apert syndrome: long-term follow-up study

Object.Brachycephaly is a characteristic feature of Apert syndrome. Traditional techniques of cranioplasty often fail to produce an acceptable morphological outcome in patients with this condition. In 1996 a new surgical procedure called “dynamic cranioplasty for brachycephaly” (DCB) was reported. The purpose of the present study was to analyze perioperative data and morphological long-term results in patients with the cranial vault deformity of Apert syndrome who were treated with DCB.

Methods.Twelve patients have undergone surgery performed using this technique since its introduction in 1991 (mean duration of follow-up review 60.2 months). Eleven patients had bicoronal synostosis and one had a combined bicoronal—bilambdoid synostosis. Perioperative data and long-term evolution of skull shape visualized on serial cephalometric radiographs were analyzed and compared with normative data. Changes in mean skull proportions were evaluated using a two-tailed paired-samples t-test, with differences being considered significant for probability values less than 0.01.

The mean operative blood transfusion was 136% of estimated red cell mass (ERCM) and the mean postoperative transfusion was 48% of ERCM. The mean operative time was 218 minutes. The duration of stay in the intensive care unit averaged 1.7 days and the mean hospital stay was 11.8 days. There were no incidences of mortality and few complications. An improvement in skull shape was achieved in all cases, with a change in the mean cephalic index from a preoperative value of 90 to a postoperative value of 78 (p = 0.000254).

Conclusions.Dynamic cranioplasty for brachycephaly is a safe procedure, yielding high-quality morphological results in the treatment of brachycephaly in patients with Apert syndrome.

Clinical Outcome of the Modified Pi-Plasty Procedure for Sagittal Synostosis

The aim of the study was to evaluate the modified pi-plasty procedure for the treatment of sagittal synostosis, assessing the issues of safety, complications, morphological outcome, and degree of parental satisfaction. A retrospective evaluation of 110 patients with nonsyndromal single suture sagittal synostosis operated on with the modified pi-plasty procedure was undertaken. Cephalometric radiographs were obtained preoperatively and postoperatively at ages 3 and 5 years in three standardized projections. The Cephalic Index and the Axial Width Ratio were determined and used as objective outcome measures. An evaluation of the radiographic digital markings was carried out using a Beaten Copper Score. A parental questionnaire was used to obtain a subjective esthetical outcome assessment. The patient population consisted of 76% boys and 24% girls with a 20% incidence of a positive familial history of craniosynostosis. The mean age at surgery was 7.73 months. Morbidity from the procedure was minimal and there were no mortalities. The Cephalic Index changed from a mean preoperative value of 65% to a postoperative mean value of 72% (P = 0.00004). The mean Axial Width Ratio changed from a preoperative 80% to 72% at the 3-year evaluation (P = 0.00029). The Beaten Copper score changed from a mean preoperative value of 2.35 to 5.42 postoperatively at 3 years (P = 0.00001). The response rate to the questionnaire was 86%, and there were significant postoperative improvements in all studied aspects of the skull shape. The modified pi-plasty is a safe technique, and it induces significant objective changes in skull morphology toward normality. It also yields a high degree of parental satisfaction with regard to aesthetic outcome, as evaluated by a written questionnaire.

Mental development after modified pi procedure: dynamic cranioplasty for sagittal synostosis

A prospective developmental assessment was performed on 26 patients operated on with dynamic cranioplasty for sagittal synostosis. Because this technique entails the application of compressive force, it was of great concern to assess the effect of surgery on development and mental status. The surgical technique used was a modified pi procedure. Perioperative variables were recorded. Six patients underwent preoperative intracranial pressure (ICP) measurements. To evaluate objectively the developmental outcome, the Griffiths' Mental Development Scales was used for analysis before and after surgery. A parental questionnaire was used for subjective outcome measurement. Preoperative ICP recordings during sleep ranged from 12.8 to 22.8 mmHg (mean, 16.1 mmHg). The mean age at the time for surgery was 6.9 months (range, 4-16 months; standard deviation [SD], 2.32 months). The surgical technique included shortening of the anteroposterior diameter of the skull by a mean of 16.6 mm. The mean global development quotient (GDQ) preoperatively was 104.5 (range, 82-144; SD, 12.4) and the mean GDQ postoperatively was 101.4 (range, 62-129; SD, 13.6). Mean age at follow-up was 16.3 months (range, 9-40 months; SD, 4.04 months). There was no significant correlation between the amount of intraoperative shortening and mental development. In comparison of means, the GDQ preoperatively did not differ significantly from the GDQ postoperatively. The modified pi procedure is safe and efficient. When surgery was performed before 1 year of age, no significant (p = 0.33) effect on mental development-either detrimental or beneficial-was demonstrated.

Variations in the diagnostic process among urologists in one region recorded using an interactive computer program

To analyse how male cases suffering from lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) are handled within a well-defined health-care region in Scandinavia, an interactive computer program containing 20 cases suffering from LUTS due to BPH was used for recording the diagnostic process and the treatment decisions; 37 out of a total of 50 urologists practicing within a small health region participated. The diagnostic process varied considerably due to a varying choice of diagnostic tests and the large differences in interpreting the qualities described by the tests. The probability that a patient would be offered a treatment within the region was analysed. For many patients the probability that a treatment was chosen was in the vicinity of 50%. No treatment probability was correlated to the symptom score of the patients. While the probability that a transurethral prostatic resection would be offered to the patients within the region was correlated significantly to urodynamic variables, residual urine and to cystoscopy findings, the probability that transurethral microwave or finasteride therapy would be offered was not correlated to any of the described qualities. The costs of the diagnostic process in all the patients incurred by each of the urologists varied by up to 500%. It was estimated that approximately 40% of the costs involved diagnostic tests that did not influence the decision to offer or not to offer treatment. In conclusion, the enormous variations in the handling of the cases recorded in the study stress the need that a management formula should be used in the handling of patients with LUTS.