Biomedical subjects

Fredrik Gewalli

Publications and source records attributed to Fredrik Gewalli.

8 recordsLinked to original sources

PubMed2006

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.

Case-Control Studies↗

PubMed2006

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.

Case-Control Studies↗

PubMed2006

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.

Animals↗

PubMed2003

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.

Adolescent↗

PubMed2003

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.

Cephalometry↗

PubMed2003

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.

Adolescent↗

PubMed2002

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.

Absorbable Implants↗

PubMed2002

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.

Analysis of Variance↗