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Introduction: Spring cranioplasty is used in selected cases of craniosynostosis. A rabbit model was used to determine (1) if cranial biomechanics modify the expected rate of spring expansion, (2) the residual spring force in situ after cranial expansion, and (3) if the spring weakens during clinical use., Materials and Methods: Twenty-seven New Zealand white rabbits were divided into 3 groups: the treatment group that underwent posterior frontal suturectomy and spring expansion (n = 15) and the control (n = 6) and sham groups (n = 6) that underwent suturectomy and incision only, respectively. Cephalography measured cranial expansion for 7 weeks. Spring force-deflection curves were measured in a dynamometer before and after use., Results: Significant cranial expansion was observed for 8 hours (15% of the total expansion). The rate of expansion decreased significantly between 48 and 96 hours followed by a second period of rapid expansion from 96 hours to 7 days (P = 0.001). Approximately 80% of expansion was achieved by 2 weeks and 90% by 3 weeks. Initial spring force was 9.4 N (range, 7.2-10.7). Once the spring had achieved 90% of its eventual expansion, it retained 40% of its original force. At the completion of cranial expansion, the residual spring force was 2.6 N (range, 1.4-4.0) or 28% of the original spring force. All springs maintained identical load-compression curves after use., Conclusions: The craniofacial structures are mechanically complex and modify the uniform expansion curve expected as the spring force decays. Significant force is maintained within the spring at the completion of cranial expansion. This may have implications for possible relapse if the springs are removed early.

Background: During spring-assisted cranioplasty, the spring transmits forces through adjacent cranium. We have previously demonstrated that the ectocranial-endocranial thickness of cranial sutures increases significantly over time in the presence of continuous spring forces. We wished to investigate if cranial bone showed similar adaptational responses., Methods: New Zealand white rabbits were randomized into a treatment group [a spring was placed across a posterior frontal suture (PFS) suturectomy and a control group (PFS suturectomy)]. Animals (n = 6) were euthanized from each group at 4, 7, and 10 weeks, respectively. A sham group (n = 6) was euthanized at 10 weeks. Frontal bone thickness was recorded at five reproducible anatomical points on the frontal bone. Histological analysis of the bone architecture was performed., Results: Frontal bone thickness was significantly greater than controls at all five sites at weeks 7 and 10. There were multiple significant differences between the 4-, 7-, and 10-week groups with each site progressively thickening over time. Histological analysis revealed a uniform increase in thickness of the endocranial and ectocranial cortical bone in the treatment groups., Conclusions: Cranial bone adapts to the presence of continuous spring cranioplasty forces by progressively thickening over time. This property is beneficial in craniosynostosis cases with very thin and poor quality bone and may partly explain the observed lack of spring erosion through bone.

Unlabelled: Expansile cranial springs are used in selected cases of craniosynostosis. The spring exerts moderate force against the relatively thin skull. We investigated whether the spring erodes through the bone and the clinical significance of any erosion relative to the cranial expansion achieved., Methods: New Zealand white rabbits (n = 10) underwent sagittal suturectomy and spring insertion. Amalgam markers were placed perpendicular to the expected direction of suture erosion. A control group (n = 10) underwent suturectomy. Radiological evaluation was performed for 7 weeks to check for migration of the spring foot., Results: The mean cranial thickness was 1.4 mm at the site of spring insertion. This compared with 1.8 mm in 7 children undergoing spring cranioplasty. The mean spring force was 9.4 N. In sagittal synostosis, the mean spring force used is 7 to 10 N.The cranial width increased 11.02 mm in the spring treatment group compared with 0.23 mm in the control group (P < 0.001). Spring erosion occurred in 4 (20%) of the 20 spring ends. Mean spring erosion for the treatment group was 0.18 mm. This was 3.2% of the mean increase in cranial width. The maximum percentage spring erosion versus cranial expansion in an individual rabbit was 14.17%. There was no statistical difference in cranial expansion between the rabbits in whom bone erosion did and did not occur., Conclusions: The degree of spring force required to effectively expand the cranium may cause bone erosion in some individuals. This degree of spring erosion was of minimal clinical significance in this animal model.

Background: Spring-assisted cranioplasty has been demonstrated to correct hypotelorism associated with metopic synostosis. In addition, the fronto-orbital axis rotates toward a more normal orientation. We postulated that spring-induced shear forces and subsequent displacement across the frontobasal sutures are the primary initial mechanisms for change in cranio-orbital morphology., Methods: Sixteen consecutive patients (32 orbits) with trigonocephaly operated on between 1999 and 2004 were studied retrospectively. After frontal remodeling, a spring was placed across the released metopic suture. Preoperative and 6-week postoperative cephalograms were used to measure the relative translation of the medial orbital wall from the midline at fixed vertical distances above and below the frontoethmoidal suture (FES). The vertical height of the spring above the frontonasal suture and the patient's age were analyzed with respect to the increase in bony interorbital distance (BIOD)., Results: There were significant increases in movement of the medial orbital wall above the FES at each measurement point (P < 0.001). There was no significant postoperative movement of the medial orbital wall below the FES at any measurement point. The relative movements above the suture suggest a degree of plastic deformation adjacent to the suture.There was no significant correlation between the age of patient or the height of the spring above the frontonasal suture and the increase in BIOD., Conclusion: Tensile spring forces are transmitted directly to the frontoethmoid suture. Most initial increases in BIOD and altered intraorbital morphology are due to distraction of cranial base sutures rather than plastic deformation.

Ventricular shunt overdrainage may cause cranial vault collapse, deformation, and secondary craniosynostosis. There is a paucity of information in the literature about this condition or successful low morbidity methods to reshape the cranial vault. Spring-assisted cranioplasty was developed in the Göthenborg Craniofacial Unit and is part of our routine protocol for the treatment of selected patients with craniosynostosis. The same treatment principles were applied to skull deformity secondary to ventricular shunt-associated deformity. Four patients with scaphocephaly secondary to ventricular shunting were treated using expansile springs. Three patients had a secondary sagittal synostosis requiring osteotomy. A further patients' sagittal suture was still patent, and this was expanded without osteotomy. Near normalization of the cranial index and significant aesthetic improvement of the cranial vault were noted in all cases. The mean preoperative cranial index increased from 0.60 to 0.71 within 4 months after surgery. The limited dissection and short operative time enabled minimal morbidity and blood loss compared with that expected with traditional craniofacial reshaping techniques. Patients with ventricular shunt-associated cranial deformity often have associated medical problems. Cranial bone is often in short supply and its quality less than optimal. In this situation, spring-assisted surgery is straightforward and offers significant advantages over traditional craniofacial reshaping techniques.

Background: Metopic synostosis, apart from the pointed forehead, typically is characterized by hypotelorism with egg-shaped orbits on cephalography and the frontoorbital axis parallel or even converging superiorly. The frontoorbital axis angle is a novel parameter for analyzing and describing the orientation of the orbits. Current methods of surgery often result in undercorrection of the almost ever-present hypotelorism. The present study was performed to analyze a new technique, capable in this respect, using steel wire springs in conjunction with a cranioplasty., Methods: A retrospective study of 23 metopic synostosis patients operated on between 1999 and 2004 was conducted. A strip midline craniectomy and frontal reshaping were combined with the insertion of a steel wire spring across the midline craniectomy, forcing lateral displacement of the orbits. Preoperative and postoperative follow-up cephalograms were obtained, and the bony medial interorbital distance was measured and compared with the bony medial interorbital distance of a control group. Perioperative data and complications were noted., Results: Preoperative mean bony interorbital distance was 10.6 mm (range, 7.7 to 13.2 mm). It increased to 15.7 mm (range, 10.4 to 22 mm) at 1.5 months postoperatively and to 16.2 mm (range, 10.9 to 24.5 mm) 5 months postoperatively. Results as judged clinically ranged from little effect to a definitive overcorrection. The frontoorbital axis was improved in every case. Average frontoorbital axis was -4 degrees (range, -33 to 23 degrees) preoperatively and 28 degrees (range, 11 to 46 degrees) postoperatively., Conclusion: It was concluded that a spring used together with a cranioplasty is a powerful tool for the correction of both hypotelorism and orbital shape in trigonocephaly.

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.

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.

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.

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.

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.

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.

A method is presented in which two well-recognized plastic surgical flap techniques are coupled; the Limberg rhomboid transposition flap and the latissimus dorsi myocutaneous flap. The technique was used in 2 patients to provide ample, innervated, and well-vascularized skin cover over myelomeningocele defects.

The microvascular sleeve anastomosis, when one vessel is inserted into another, is presented in detail. Modifications of the original procedure are described and their performance is analyzed. It appears that the original sleeve anastomosis is a safe and expedient operative technique, whereas several present modifications thereof seem to lead to decreased patency rates. Insufficient dilatation of both vessel ends probably is the most important single factor in this regard.