Nonsyndromic Single-suture Synostosis Research Articles

Introduction of a ROTEM-assisted strategy improves patient blood management in children undergoing open craniosynostosis repair

Purpose The surgical correction of craniosynostosis by open cranial vault reconstruction (OCVR) is often associated with significant blood loss and perioperative blood transfusion demand. Because of transfusion risks, several attempts have been made to eliminate the need for perioperative homologous blood transfusion with the implementation of goal-directed transfusion protocols. The aim of this study was to determine whether the introduction of a rotational thromboelastometry (ROTEM)–assisted patient blood management strategy would decrease the intraoperative blood transfusion and blood loss levels. Methods Patients younger than 2 years of age who were diagnosed with nonsyndromic single suture synostosis and underwent primary OCVR were investigated in this retrospectively designed cohort study. The children were equally divided into 2 study groups according to the availability of the ROTEM-assisted protocol. The control group had surgery before introduction of the new protocol, whereas the study group was operated on subsequently. Demographic, blood loss, and transfusion data of the preprotocol cohort were compared with those of the postprotocol cohort. Results In total, 100 children, separated in 2 groups (50 patients each), were analyzed. The mean age at the time of surgery was 8.5 months in the pre-ROTEM-assisted protocol group, and 8.7 months in the postimplementation group. The estimated blood volume loss dropped from 60.8 mL/kg to 49.6 mL/kg after initiation of the current strategy. The intraoperative packed red blood cell (PRBC) transfusion volume decreased from 32.6 mL/kg to 17.1 mL/kg. Administration of PRBCs in the postoperative period also was reduced, compared with the period before implementation of the ROTEM-assisted regimen, from 21.8 mL/kg to 15.9 mL/kg. The average length of hospital stay was reduced from 5.4 days to 4.7 days after use of the ROTEM-assisted protocol. Conclusions As indicated by our results, the use of a ROTEM-assisted protocol is associated with considerable reduction in blood volume loss and perioperative allogeneic transfusion requirements in the surgical management of craniosynostosis with OCVR.

Partial Suture Fusion in Nonsyndromic Single-Suture Craniosynostosis.

Partial synostosis of cranial sutures has been shown to have clinical and diagnostic significance. However, there is limited published information about how suture fusion progresses over time. In this study, we evaluate patients with nonsyndromic single-suture synostosis. We aim to define the incidence of partial versus complete suture fusion and whether a correlation exists between the degree of suture fusion and age. Two hundred fifty-four patients with nonsyndromic single-suture synostosis were evaluated. Preoperative computed tomography (CT) scans were rendered in 3-dimensions, all sutures were visualized and assessed for patency or fusion, and length of fusion was measured. Findings were grouped according to suture type (sagittal, coronal, metopic, or lambdoid), the degree of fusion (full, >50%, or <50%), and patient age at time of CT scan (0-90, 91-180, 181-360, or >360 days). Data were analyzed to correlate patient age versus the degree of suture fusion. For all patients, 72% had complete and 28% had partial synostosis. Ratios of full to partial fusion for each suture type were as follows: sagittal 97:36, coronal 35:22, metopic 46:4, and lambdoid 4:10. The sagittal, coronal, and metopic groups demonstrated greater probabilities of complete suture fusion as patient age increases (P = .021, P < .001, P = .001, respectively). This trend was also noted when all sutures were considered together by age-group (P < .001). We note a partial suture fusion rate of 28.3%. Our analysis shows a correlation between the extent of suture synostosis and patient age. Finally, we demonstrate that different sutures display different patterns of partial and complete fusion.

The Directive Growth Approach for Nonsyndromic, Unicoronal Craniosynostosis: Patient and Clinical Outcomes.

Deformities of the cranium in patients with nonsyndromic single-suture synostosis occur because of growth restriction at fused sutures and growth over compensation at normal sutures. Traditional surgery includes ostectomies of the synostotic suture to release these restricted areas and osteotomies to enable immediate cranial remodeling. In the process of reshaping the cranium, traditional approaches usually involve obliteration of both the normal functioning suture and the pathologic suture. The directive growth approach (DGA) is a new, simpler, more natural way to repair deformities caused by single-suture cranial synostosis. The DGA works by reversing the original deforming forces by temporarily restricting growth in areas of over compensation and forcing growth in areas of previous synostotic restriction. Most importantly, it preserves a normal functioning suture to allow for improved future cranial growth. Eighteen consecutive nonsyndromic patients with unilateral coronal synostosis were used to illustrate the efficacy of the DGA. Ten patients who underwent DGA treatment were compared with a control group of 8 patients treated with traditional frontal orbital advancement. Postoperative three-dimensional computed tomography (CT) comparison measurements were taken, including bilateral vertical and transverse orbital dimensions, lateral orbital rim to external auditory canal, and forehead measurements from the superior aspect of the orbital rim to the pituitary fossa. The traditional treatment group showed absence of the coronal sutures bilaterally on long-term CT scans. The DGA group showed normal coronal sutures on the unaffected sides. Postoperative CT measurements showed no statistical difference between the 2 techniques (P < 0.05).

Implementation of a Tranexamic Acid Protocol to Reduce Blood Loss During Cranial Vault Remodeling for Craniosynostosis

Pediatric cranial vault remodeling for repair of craniosynostosis is associated with significant blood loss and transfusion requirements. Beginning in 2011, the authors evaluated the impact tranexamic acid (TXA) on blood loss and blood product transfusion for children less than 15 months of age undergoing primary surgical repair of nonsyndromic single suture craniosynostosis. Following institutional review board approval, the authors performed a retrospective study of all children undergoing surgical correction of craniosynostosis at Oregon Health & Science University from 2005 to 2015. All available records were reviewed, and patient data were collected from the time of preoperative evaluation until discharge, comparing patient and clinical variables before and after the implementation of perioperative TXA. Of a total of 259 patients with craniosynostosis, 187 had nonsyndromic single-suture involvement; 69 of these patients (36.9%) received TXA. A single surgical team (AAK and NRS) performed all operations. Median age at the time of surgery was 8.1 months (interquartile range [IQR] of 6.0-9.8 months). The TXA group had a significant reduction in estimated intraoperative blood loss (26 mL/kg versus 36 mL/kg, P <0.001), cell saver volume transfused 6 mL/kg versus 10 mL/kg, P <0.001), red cell transfusion volume (32 mL/kg versus 42 mL/kg, P <0.001), exposure to plasma transfusion (0% versus 24% P <0.001), exposure to cryoprecipitate transfusion (0% versus 16%, P <0.001), and exposure to platelet transfusion (0% versus 7.6% P = 0.03). Despite reduced red cell transfusion, the TXA-treated patients exhibited similar postoperative hematocrits (30.4 versus 30.3 P = 0.906) to those not treated with TXA. Use of TXA was associated with reduced length of stay (4 days IQR 3-4 versus 4 days IQR 4-5, P <0.001) and reduced postoperative output from surgically placed drains (181 mL versus 311 mL P <0.001). There was no difference in postoperative complications between groups and no deaths in either group. The introduction of TXA for nonsyndromic single-suture synostosis repair at our institution has significantly reduced blood loss and blood product and plasma transfusion during and following primary cranial vault remodeling for single suture craniosynostosis. Postoperative hematocrit was similar in the TXA-treated and untreated groups despite reduced red cell transfusion in the treated group. In addition, TXA use in this population has eliminated the need for plasma transfusion, and is associated with a shorter hospital stay. No difference in postoperative complications was observed. Our data provide support for further investigation of TXA treatment to improve clinical outcomes in children undergoing pediatric cranial vault remodeling.

Delayed intracranial hypertension after cranial vault remodeling for nonsyndromic single-suture synostosis

Delayed intracranial hypertension may occur after cranial vault remodeling for synostosis and may result in visual loss and developmental delay. Delayed intracranial hypertension is relatively common in children with syndromic, multisuture synostosis, but the incidence is poorly defined in children with single-suture nonsyndromic synostosis. This study evaluates the frequency of reoperation for delayed intracranial hypertension after single-suture synostosis repair. Patients who had undergone cranial vault remodeling for nonsyndromic single-suture synostosis and were treated at a single tertiary pediatric hospital between July 2000 and December 2010 were analyzed for the occurrence of delayed intracranial hypertension and reoperation for cranial vault remodeling. Eighty-one patients with clinical follow-up of at least 3 years were analyzed from a total of 156 consecutive patients. The average patient age at the initial operation was 9.1 months. Five (6.2%) of 81 patients presented with delayed clinical and ophthalmological signs and symptoms of intracranial hypertension following initial cranial vault reconstruction, confirmed indirectly in each case by CT findings and directly by intracranial pressure monitoring. These 5 patients underwent repeat cranial vault reconstruction. Calvarial growth restriction and intracranial hypertension occur sporadically following primary cranial vault reconstruction for single-suture nonsyndromic cranial synostosis. In this series, delayed intracranial hypertension occurred only in male patients who underwent primary repair of isolated sagittal synostoses at an age less than or equal to 5 months.

Minimally Invasive Strip Craniectomy for Sagittal Synostosis

The most common approaches used today for the correction of sagittal synostosis involve large craniectomies and extensive cranial vault remodeling. Although these techniques ultimately yield very good cosmetic results, they have significant drawbacks. They are lengthy, expensive, associated with significant blood loss, universally require transfusions, and often result in prolonged hospitalization.We present here our 5-year experience with correction of sagittal synostosis using the recently described minimally invasive strip craniectomy followed by postoperative cranial vault helmet molding. During this period, we treated a total of 97 children with nonsyndromic single-suture synostosis. The first 46 of 67 children treated for sagittal synostosis had at least 1 year of postoperative follow-up and were included in the analysis. There were 33 boys and 13 girls. Patients' mean age at surgery was 3.1 months, and the mean weight was 6.1 kg. The mean operative time was 75 minutes. The estimated blood loss during the procedure was 56 mL. Eight patients received blood transfusions during surgery (17.4%) and 3 patients received after surgery (6.5%). There were no significant postoperative complications. The mean hospitalization was 2.2 days. Excellent aesthetic outcomes were noted in all patients. The change in cranial index from a preoperative value of 0.7 to 0.8 postoperatively was virtually stabilized 3 months after the surgical intervention. Significantly better correction rates were observed in the youngest patients.Because of its excellent attributes, minimally invasive strip craniectomy followed by postoperative helmet molding is likely to become the preferred treatment modality for the correction of sagittal synostosis.

IGF1R variants associated with isolated single suture craniosynostosis

The genetic contribution to the pathogenesis of isolated single suture craniosynostosis is poorly understood. The role of mutations in genes known to be associated with syndromic synostosis appears to be limited. We present our findings of a candidate gene resequencing approach to identify rare variants associated with the most common forms of isolated craniosynostosis. Resequencing of the coding regions, splice junction sites, and 5' and 3' untranslated regions of 27 candidate genes in 186 cases of isolated non-syndromic single suture synostosis revealed three novel and two rare sequence variants (R406H, R595H, N857S, P190S, M446V) in insulin-like growth factor I receptor (IGF1R) that are enriched relative to control samples. Mapping the resultant amino acid changes to the modeled homodimer protein structure suggests a structural basis for segregation between these and other disease-associated mutations found in IGF1R. These data suggest that IGF1R mutations may contribute to the risk and in some cases cause single suture craniosynostosis.

Surgical Treatment for Scaphocephaly and a Calcified Cephalohematoma

Craniosynostosis is the premature fusion of 1 or more of the cranial sutures, with sagittal synostosis being the most common nonsyndromic single suture synostosis. The pathogenesis of craniosynostosis has been extensively studied and is likely multi-factorial. A complex interaction between the dura and overlying suture via multiple growth factors seems to play the most important role. There have been 3 published studies with patients presenting with scaphocephaly and a cephalohematoma, which raises the question of how the 2 conditions may be related. Cephalohematomas can be seen after trauma and a number of other causative factors but usually resorb over time without sequela. In a small percentage of cases, the hematoma persists and calcifies, leading to significant asymmetry and deformity of the skull. Once it reaches this point, surgical intervention may be required to correct the resulting skull deformity. We present a child with scaphocephaly and a cephalohematoma who underwent surgical correction with resection of the cephalohematoma and sagittal suturectomy with spring-assisted surgery.

A Preliminary Investigation of Postoperative Molding to Improve the Result of Cranial Vault Remodeling

A Preliminary Investigation of Postoperative Molding to Improve the Result of Cranial Vault Remodeling

Concordant Contralateral Lambdoidal Synostosis in Dizygotic Twins

Twin studies have been widely used to investigate genetic versus environmental causality of malformations. While there are numerous reports of concordant sutural fusions in syndromic twins, there are few cases in siblings with nonsyndromic single suture synostosis. Lambdoidal synostosis has no clear genetic etiology. Discordant synostosis has been reported in one monozygotic twin; there is also an unsubstantiated report of concordance in dizygotic twins. We describe dizygotic twins concordant for contralateral lambdoidal synostosis. Mutational analysis for FGFR 1,2,3 was negative. Given the low incidence, absence of reported inheritability, and lack of documented concordance in monozygotic twins, the pathogenesis of isolated lambdoidal fusion can only be ascribed to stochastic influences.