Comparison of spring-mediated cranioplasty to minimally invasive strip craniectomy and barrel staving for early treatment of sagittal craniosynostosis

Patient-Reported Outcome Measures (PROM) After Endoscopic and Open Correction of Sagittal Suture Synostosis-In Comparison With Surgeons' and Lay Persons' Assessment

OBJECTIVE

The presented study compares the qualitative subjective outcome assessment after open and endoscopic-assisted correction of sagittal suture synostosis by 3 evaluating groups.

METHODS

The assessment of the postoperative outcome of 3 groups-parents, surgeons and lay persons ("neutrals")-was evaluated by answering items of a patient-reported outcome measurement (PROM) questionnaire. Furthermore, a subjective outcome assessment was performed by the group of surgeons with the ERN CRANIO photo score for sagittal synostosis.

RESULTS

The PROM assessment of all 3 evaluating groups demonstrated a significant reduction of the severity of the sagittal synostosis phenotype after open and endoscopic-assisted correction without any difference between both techniques. Although there was a significant correlation of the outcome assessment of all 3 groups, parents scored the postoperative phenotype significantly better than the group of surgeons and "neutrals". The assessment by the 3 evaluating groups showed a significant correlation, which was highest between the groups of surgeons and the groups of "neutrals" Correspondingly, there was a significant improvement of the ERN CRANIO photo score by the group of surgeons without any difference between both operative techniques and a high correlation between the PROM and the ERN Cranio photo score assessment by the surgeons.

CONCLUSION

Both open and endoscopic-assisted correction of sagittal suture synostosis provided significant improvement of the phenotype in the PROM assessment of parents, surgeons and "neutrals" without difference between the 2 operative techniques. The combination of PROM assessment by parents and the ERN CRANIO photo score evaluation performed by health care professionals offers an effective assessment for subjective qualitative judgment of the severity of sagittal synostosis.

Non-syndromic craniosynostosis

Craniosynostosis is characterized by the premature fusion of one or more major cranial sutures at birth or soon after. Single-suture non-syndromic craniosynostosis (NSC) is the most common form of craniosynostosis and includes the sagittal, metopic, unicoronal and unilambdoid subtypes. Characterized by an abnormal head shape specific to the fused suture type, NSC can cause increased intracranial pressure. Cranial sutures either originate from the neural crest or arise from mesoderm-derived mesenchymal stem cells. A mixture of environmental and genetic factors contributes to NSC, with genetic causes following a largely polygenic model. Physical examination is used to identify the majority of patients, but accompanying radiographic imaging can be confirmatory. The three major surgical techniques in use to treat NSC are cranial vault remodelling, strip craniectomy and spring-assisted cranioplasty. Surgical intervention is ideally performed in the first year of life, with a mortality of <1%. Health-care disparities contribute to delayed initial presentation and timely repair. Optimal timing of surgery and comparative outcomes by surgical technique remain under active study. School-age children with treated NSC on average have subtle, but lower cognitive and behavioural performance. However, patient-reported quality of life outcomes are comparable to those in control individuals.

Assessment of Minimally Invasive Surgical Techniques for Sagittal Craniosynostosis: A Multicenter Time Series Study

BACKGROUND

Minimally invasive strip craniectomy is a well-established treatment for sagittal craniosynostosis; however, the temporality of change in head shape has not been assessed. In this study, the authors performed head shape analysis to compare time-series-based clinical outcomes among 3 different surgical techniques across 3 academic centers for the treatment of sagittal craniosynostosis.

METHODS

Retrospective, longitudinal 3-dimensional (3D) images were collected from patients who underwent surgery for the correction of sagittal craniosynostosis for up to 5 years postoperation. The surgical methods studied include spring-assisted craniectomy, narrow-strip craniectomy plus orthotic helmet therapy, and wide-strip craniectomy with biparietal and bitemporal barrel stave wedge osteotomies plus orthotic helmet therapy. Postoperative 3D images were binned into 6 age groups. Cranial index measurements were calculated on 3D images. The 3D whole-head composite images were generated for each procedure to visually represent longitudinal outcomes.

RESULTS

The median (interquartile range) cranial index measurements at 3- to 5-years postoperative follow-up were 75.9 (73.1 to 78.6) for spring-assisted, 75.9 (75.4 to 78.5) for narrow-strip, and 79.4 (76.4 to 81.9) for wide-strip procedures. The wide-strip cranial index was significantly different from the spring-assisted and narrow-strip groups ( P < 0.001). Concerning 3D analysis, patients receiving spring-assisted procedures showed normalization of frontal bossing and skull height compared with age-matched controls, whereas patients receiving wide-strip procedures showed greater correction of occipital bulleting. Patients receiving narrow-strip procedures had intermediate results between these outcomes.

CONCLUSIONS

There was no statistically significant regression in longitudinal cranial index measurements across the 3 techniques aimed at treating sagittal craniosynostosis. Longitudinal comparison of 3D head shape outcome demonstrated satisfactory correction of scaphocephalic deformity across all 3 surgical groups.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Craniometric and Aesthetic Outcomes in Craniosynostosis Surgery: A Systematic Review and Meta-Analysis

ObjectiveTo systematically review the published comparative aesthetic outcomes, and its determinants, for craniosynostoses surgically treated by minimally-invasive cranial procedures and open cranial vault remodeling (CVR).DesignPRISMA-compliant systematic review.SettingNot-applicable.Patients/ParticipantsArticles were included if they compared spring cranioplasty, strip minimally-invasive craniectomy or CVR for outcomes related to aesthetics or head shape. Forty-two studies were included, comprising 2402 patients.InterventionsNone.Main Outcome Measure(s)The craniometric and PROM used to determine surgical outcomes.ResultsTwenty-five studies (59%) evaluated sagittal craniosynostosis, with metopic (7;17%) and unicoronal (4;10%) the next most prevalent. Thirty-eight studies (90%) included CVR, 24 (57%) included strip craniectomy with helmeting, 9 (22%) included strip craniectomy without helmeting, 11 (26%) included spring cranioplasty, and 3 (7%) included vault distraction. A majority of studies only used 1 (43%) or 2 (14%) craniometric measures to compare techniques. In sagittal synostosis, 13 (59%) studies showed no difference in craniometric outcomes, 5 (23%) showed better results with CVR, 3 (14%) with strip craniectomy, and 1 (5%) with springs. In studies describing other synostoses, 10/14 (71%) were equivocal. Subjective outcome measures followed similar trends. Meta-analysis shows no significant difference in cranial index (CI) outcomes between CVR and less invasive procedures in patients with sagittal synostosis.ConclusionsThere is no difference in CI outcomes between CVR and less invasive procedures. The majority of literature comparing craniometric and aesthetic outcomes between CVR and less invasive procedures shows equivocal results for sagittal synostosis. However, the heterogeneity of data for other craniosynostoses did not allow meta-analysis.

Endoscopic versus open treatment for sagittal craniosynostosis: a systematic review and meta-analysis

Sagittal craniosynostosis is the most common form of craniosynostosis. Patients diagnosed with this condition can undergo surgical management using either the conventional open surgery method or the modern approach of minimally invasive endoscope-assisted craniectomy. The present study aimed to compare different outcomes of patients with sagittal craniosynostosis treated with endoscopic procedures versus open surgery. Multiple databases were systematically searched for studies comparing endoscopic and open repair of sagittal craniosynostosis. Outcomes analyzed included estimated blood loss, length of hospital stay, operative time, transfusion rates, complications, reoperations, and cranial indices. Random-effects meta-analyses were performed. Seventeen studies with 2,365 patients were included. Endoscope-assisted surgery showed significantly lower estimated blood loss (mean difference - 118.47 ml), shorter hospital stays (-2.08 days), and reduced operative times (-84.70 min) compared to open surgery. Intraoperative and postoperative transfusion rates were lower with endoscopic treatment (risk ratios 0.22 and 0.30, respectively). Postoperative complications were reduced with endoscopic repair (RR 0.39), without differences in intraoperative complications or reoperations. Preoperative and postoperative cranial indices slightly favored endoscopic approaches. Endoscope-assisted surgery for sagittal craniosynostosis offers perioperative advantages including reduced blood loss, shorter hospitalizations, briefer operative times, lower transfusion needs, and fewer postoperative complications compared to open calvaria remodeling, while achieving comparable cranial reshaping. These findings support an increasing use of minimally invasive endoscopic techniques for repair of sagittal craniosynostosis.

Long-Term Outcomes of Regional Morphology in Spring-Assisted Surgery and Cranial Vault Remodeling

BACKGROUND

Spring-assisted surgery (SAS) and cranial vault remodeling (CVR) are widely used surgical techniques to correct sagittal craniosynostosis (SC). The authors evaluated changes in regional morphology of patients with SC who had undergone SAS or CVR, using the frontal bossing index (FBI), occipital bulleting index, vertex narrowing index (VNI), and scaphocephalic severity index (SCI) to capture differences in anterior protrusion, posterior protrusion, width restriction, and global dysmorphology, respectively.

METHODS

Indices were measured on computed tomography and 3-dimensional photographs (n = 788) of 257 patients with SC from 2001 through 2022 who underwent SAS (n = 177) or CVR (n = 80). Short-term and long-term outcomes were evaluated.

RESULTS

Mean age at time of surgery was older in the CVR cohort (CVR, 22.55 ± 16.00 years; SAS, 4.56 ± 2.24 years) (P < 0.05). Before surgery, the SAS cohort had more severe regional dysmorphology in FBI, VNI, and SCI (P < 0.05) relative to the CVR cohort. Frontal bossing consistently improved over time in both cohorts. Head width improved as soon as 0 to 6 months postoperatively (P < 0.05), but it consistently regressed after the initial improvement in both cohorts. Global head shape initially improved in the CVR cohort but regressed over time. In contrast, patients in the SAS group maintained improvements in SCI over time, with significantly better percentage change in every age interval (P < 0.05).

CONCLUSIONS

The FBI, occipital bulleting index, VNI, and SCI are useful tools for monitoring head shape and growth. SAS and CVR achieve similar morphologic outcomes, despite more severe preoperative morphology in the SAS group. Trending index changes with growth between the 2 cohorts suggest improved longevity of correction in the SAS group.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

A coddling of the sagittal suture: inequality in spring-assisted expansion

PURPOSE

We examined differences in long-term morphometric outcomes of spring-mediated cranioplasty (SMC) for various forms of isolated nonsyndromic sagittal craniosynostosis.

METHODS

A retrospective review was performed of children who underwent SMC from 2011 to 2020 at the Children's Hospital of Philadelphia. Cephalic indices (CI), Whitaker grades, parietal bone thickness, and degree of suture fusion were assessed. Frontal bossing and vertex-nasion-opisthocranion (VNO) angles were compared to a normal control group.

RESULTS

Fifty-four subjects underwent surgery at age 3.6 ± 1.0 months with follow-up of 6.3 ± 1.8 years. Mean CI was 75.2 ± 4.1 at 5.9 ± 2.0 years postoperatively. Mean CI were 75.8 ± 4.1 (n = 32), 76.4 ± 4.0 (n = 22), and 77.1 ± 4.8 (n = 11) at 5, 7, and 9+ years postoperatively, respectively. Three (5.6%) required reoperation for persistent scaphocephalic cranial deformity. Fifty-one (94.4%) were Whitaker Grade I. On physical examination, 12 (22.2%) demonstrated craniofacial abnormalities. At long-term follow-up, there were no differences in frontal bossing angle (102.7 ± 5.2 degrees versus 100.7 ± 5.6 degrees, p = .052) and VNO angle (44.9 ± 3.3 degrees versus 43.9 ± 2.2 degrees, p = .063) between study and control groups. Younger age at surgery predicted a lower Whitaker grade, more normalized VNO angle, and greater change in CI during active expansion. Increased percentage fused of the posterior sagittal suture predicted a higher Whitaker grade, while decreased anterior fusion was associated with frontal bossing and temporal hollowing.

CONCLUSIONS

Overall, children undergoing spring-mediated cranioplasty for sagittal craniosynostosis demonstrated maintenance of CI, favorable cosmetic outcomes, and a low reoperation rate at mid-term follow-up. Early intervention is associated with improved aesthetic outcomes, and regional fusion patterns may influence long-term craniofacial dysmorphology.

Three-Dimensional Assessment of Frontal Bossing and Temporal Pinching in Patients with Sagittal Craniosynostosis Using Curvature Analysis

BACKGROUND

Sagittal craniosynostosis results in varying degrees of frontal bossing and bilateral temporal pinching. This study assessed the three-dimensional changes in these regions using curvature analysis and volumetric analysis before and 1 year after extended sagittal strip craniectomy (ESC) with postoperative helmet therapy.

METHODS

A retrospective review of three-dimensional photographs of 50 subjects treated with ESC with postoperative helmet therapy and 50 age-matched controls was performed. Images were collected preoperatively and 1 year postoperatively. Forehead convexity and temple concavity were quantified. Computed tomographic scans of subjects with and without sagittal synostosis were analyzed to assess the percentage of total intracranial volume (ICV) in the anterior cranial fossa before and after ESC with postoperative helmet therapy.

RESULTS

Forehead convexity in the ESC with postoperative helmet therapy group preoperatively (24.49 ± 3.16 m -1 ) was significantly greater than controls (22.48 ± 3.84 m -1 ; P = 0.005). Forehead convexity significantly decreased after ESC with postoperative helmet therapy (18.79 ± 2.43 m -1 ; P < 0.001) and did not differ from controls (19.67 ± 3.08 m -1 ; P = 0.115). The ESC group had more concave temples preoperatively (-10.27 ± 4.37 m -1 ) as compared with controls (-6.99 ± 3.55 m -1 ; P < 0.001). Temple concavity significantly decreased after ESC (-4.82 ± 3.17 m -1 ; P < 0.001) and did not differ from controls (-5.64 ± 3.27 m -1 ; P = 0.075). In the ESC group, the percentage ICV in the anterior cranial fossa decreased from 22.03% to 18.99% after surgery, whereas the anterior volume in controls was stable (17.74% to 16.81%).

CONCLUSIONS

The ESC group had significantly greater forehead convexity, temple concavity and anterior cranial fossa volume compared with controls. One year after ESC with postoperative helmet therapy, forehead convexity, temple concavity, and percentage ICV in the anterior fossa were comparable to controls.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Introduction of Spring-Assisted Cranioplasty for Sagittal Craniosynostosis in a Craniofacial Service: A Report of Early Experience

Spring-assisted cranioplasty (SAC) for the treatment of craniosynostosis uses internal springs to produce dynamic changes in cranial shape over several months before its removal. The purpose of this study was to report the first Egyptian experiences with SAC in the treatment of children with sagittal synostosis and evaluate the preliminary outcome. A total of 17 consecutive patients with scaphocephaly underwent SAC with a midline osteotomy along the fused sagittal suture and insertion of 3 springs with bayonet-shaped ends across the opened suture. Operative time, blood transfusion requirements and length of ICU, total hospital stay, and complications graded according to Oxford protocol classification were recorded. Spring removal was performed once re-ossification of the cranial defect occurred. All patients successfully underwent SAC without significant complications. The mean age at surgery was 6.8 months. The mean time of the spring insertion surgery was 63 minutes (SD 9.7). Blood transfusion was needed in less than half of the patients (41.2%).The mean duration of hospital stay was 3.2 days. The mean timing of spring removal was 5.5 months (SD 0.4). The mean time of the second surgery (spring removal) was 22.8 minutes (SD 3.6). In conclusion, SAC can easily be incorporated into the treatment armamentarium of craniofacial surgeons. The technique offers a safe and minimally invasive option for the treatment of sagittal craniosynostosis with the benefit of limited dural undermining, minimal blood loss, operative time, anesthetic time, ICU stay, and hospital stay.

Persistent Cranial Defects After Endoscopic Sagittal Synostosis Surgery

INTRODUCTION

Incomplete cranial ossification is a rare complication of calvarial-vault remodeling for sagittal synostosis often requiring reoperation. Studies show an incidence ranging from 0.5% to 18%.

METHODS

Infants with sagittal synostosis who underwent endoscopic sagittal synostectomy and barrel stave osteotomies with postoperative orthotic helmeting between 2003 and 2021 were included with minimum follow-up until the completion of helmeting.

RESULTS

Of 90 patients, 86 met inclusion; 3 had defects (3.5%). Patients with and without cranial defects had no difference in age of surgery (113 versus 131 d), duration helmeting (6.6 versus 7.0 mo), or perioperative/postoperative complications. Two underwent reoperation for recurrence. Patients with cranial defects manifested the evidence of developmental concerns more than patients without (100% versus 16.9%).The average cranial defect size was 19.33 cm 2 and age at surgery 4.29 years. All were managed with cranial particulate bone grafting with addition of bone matrix and SonicWeld plate. The first had 6×6 cm posterior defect requiring cranioplasty at 4.86 years with excellent healing. The second had a 3×6 cm posterior and 1×1 cm anterior defect, underwent cranioplasty at 4.14 years with persistent 4×6 defect, requiring repeat cranioplasty at 5.3 years. The third had a 3×5 cm posterior defect and underwent cranioplasty at 3.88 years with continued defect, planning for repeat intervention.

CONCLUSIONS

This is the largest documented series of reoperations for incomplete ossification after endoscopic sagittal synostectomy with postoperative helmet treatment. The authors report a 3.5% rate of cranial defects, managed with bone grafting, bone matrix, and absorbable plates. Patients with poor ossification may have a propensity toward developmental concerns.

Endoscopic strip craniectomy with molding helmet therapy versus spring-assisted cranioplasty for nonsyndromic single-suture sagittal craniosynostosis: a systematic review

OBJECTIVE

Endoscopic strip craniectomy with postoperative molding helmet therapy (ESC-H) and spring-assisted cranioplasty (SAC) are commonly used minimally invasive techniques for correction of nonsyndromic sagittal craniosynostosis, but it is unclear which, if either, is superior. Therefore, the authors undertook a systematic review to compare ESC-H with SAC for the surgical management of nonsyndromic single-suture sagittal craniosynostosis.

METHODS

Studies were identified through a systematic and comprehensive search of four databases (Embase, MEDLINE, and two databases in the Cochrane Library). Databases were searched from inception until February 19, 2021. Pediatric patients undergoing either ESC-H or SAC for the management of nonsyndromic single-suture sagittal craniosynostosis were included. Systematic reviews and meta-analyses, single-patient case reports, mixed cohorts of nonsyndromic and syndromic patients, mixed cohorts of different craniosynostosis types, and studies in which no outcomes of interest were reported were excluded. Outcomes of interest included reoperations, blood transfusion, complications, postoperative intensive care unit (ICU) admission, operative time, estimated blood loss, length of hospital stay, and cephalic index. Pooled summary cohort characteristics were calculated for each outcome of interest. Methodological quality was assessed using the Newcastle-Ottawa Scale. The study was reported in accordance with the 2020 PRISMA statement.

RESULTS

Twenty-two studies were eligible for inclusion in the review, including 1094 patients, of whom 605 (55.3%) underwent ESC-H and 489 (44.7%) underwent SAC for nonsyndromic sagittal craniosynostosis. There was no difference between the pooled estimates of the ESC-H and SAC groups for operative time, length of stay, estimated blood loss, and cephalic index. There was no difference between the groups for reoperation rate and complication rate. However, ESC-H was associated with a higher blood transfusion rate and higher postoperative ICU admission.

CONCLUSIONS

The available literature does not demonstrate superiority of either ESC-H or SAC, and outcomes are broadly similar for the treatment of nonsyndromic sagittal craniosynostosis. However, the evidence is limited by single-center retrospective studies with low methodological quality. There is a need for international multicenter randomized controlled trials comparing both techniques to gain definitive and generalizable data.

Management of Sagittal and Lambdoid Craniosynostosis: Minimally Invasive Approaches

The resurgence of strip craniectomies began in the mid-1990s with advances in surgical technique and anesthesia coupled with the critical observation that earlier interventions benefitted from an easily molded skull. Jimenez and Barone's pioneering introduction of endoscopic approaches to strip craniectomies coupled with postoperative helmeting in newborns and young infants and Claes Lauritzen's introduction of spring-mediated cranioplasty began the era of minimally invasive approaches in the surgical correction of craniosynostosis. This article provides technical descriptions of these treatment modalities, a comparative literature review, and our institutional algorithms for the correction of sagittal craniosynostosis and unilambdoid craniosynostosis.

Predicting Changes in Cephalic Index Following Spring-mediated Cranioplasty for Nonsyndromic Sagittal Craniosynostosis: A Stepwise and Machine Learning Algorithm Approach

BACKGROUND

Spring-mediated cranioplasty (SMC) is an increasingly utilized technique to treat patients with nonsyndromic sagittal craniosynostosis, but variables impacting outcomes are incompletely understood. The purpose of this study was to determine variables most predictive of outcomes following SMC, primarily changes in cephalic index (CI).

METHODS

Patients with nonsyndromic sagittal craniosynostosis undergoing SMC at our institution between 2014 and 2021 were included. Cephalic index was measured from patient computed tomography scans, x-rays, or by caliper-based methods. Parietal bone thickness was determined from patient preoperative computed tomography. Stepwise multiple regression analysis, least absolute shrinkage and selection operator, and random forest machine learning methods were used to determine variables most predictive of changes in CI.

RESULTS

One hundred twenty-four patients were included. Stepwise multiple regression analysis identified duration of spring placement (P=0.007), anterior spring force (P=0.034), and anterior spring length (P=0.043) as statistically significant predictors for changes in CI. Least absolute shrinkage and selection operator analysis identified maximum spring force (β=0.035), anterior spring length (β=0.005), posterior spring length (β=0.004), and duration of spring placement (β=0.0008) as the most predictive variables for changes in CI. Random forest machine learning identified variables with greatest increase in mean squared error as maximum spring force (0.0101), anterior spring length (0.0090), and posterior spring length (0.0056).

CONCLUSIONS

Maximum and total spring forces, anterior and posterior spring lengths, and duration of spring placement were the most predictive variables for changes in CI following SMC. Age at surgery and other demographic variables were inferior predictors in these models.

A Computational Framework to Predict Calvarial Growth: Optimising Management of Sagittal Craniosynostosis

The neonate skull consists of several bony plates, connected by fibrous soft tissue called sutures. Premature fusion of sutures is a medical condition known as craniosynostosis. Sagittal synostosis, caused by premature fusion of the sagittal suture, is the most common form of this condition. The optimum management of this condition is an ongoing debate in the craniofacial community while aspects of the biomechanics and mechanobiology are not well understood. Here, we describe a computational framework that enables us to predict and compare the calvarial growth following different reconstruction techniques for the management of sagittal synostosis. Our results demonstrate how different reconstruction techniques interact with the increasing intracranial volume. The framework proposed here can be used to inform optimum management of different forms of craniosynostosis, minimising the risk of functional consequences and secondary surgery.

Update in Management of Craniosynostosis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the craniofacial dysmorphology of craniosynostosis, and the variation of each type. 2. Identify the functional concerns and learn the rationale behind timing of operative intervention. 3. Approach each dysmorphology critically and identify the operative intervention needed to improve form and function 4. Understand and address the specific issues related to syndromic craniosynostosis and be able to delineate management plan.

SUMMARY

Craniosynostosis is a condition in which premature fusion of one or more cranial sutures lead to abnormal head shape and growth restriction of the brain. Nonsyndromic craniosynostosis occurs in isolation, and usually involves a single suture, whereas syndromic craniosynostosis may involve multiple sutures and is associated with extracraniofacial findings. Although surgical management can be similar, the treatment plan must take into consideration issues specific to the syndromes. This article aims to provide a concise overview of the authors' current understanding regarding the presentation, treatment principle, surgical option, and debates in craniosynostosis.

Parietal bone thickness for predicting operative transfusion and blood loss in patients undergoing spring-mediated cranioplasty for nonsyndromic sagittal craniosynostosis

OBJECTIVE

Variables that can predict outcomes in patients with craniosynostosis, including bone thickness, are important for surgical decision-making, yet are incompletely understood. Recent studies have demonstrated relative risks and benefits of surgical techniques for correcting head shape in patients with nonsyndromic sagittal craniosynostosis. The purpose of this study was to characterize the relationships between parietal bone thickness and perioperative outcomes in patients who underwent spring-mediated cranioplasty (SMC) for nonsyndromic sagittal craniosynostosis.

METHODS

Patients who underwent craniectomy and SMC for nonsyndromic sagittal craniosynostosis at a quaternary pediatric hospital between 2011 and 2021 were included. Parietal bone thickness was determined on patient preoperative CT at 27 suture-related points: at the suture line and at 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm from the suture at the anterior parietal, midparietal, and posterior parietal bones. Preoperative skull thickness was compared with intraoperative blood loss, need for intraoperative transfusion, and hospital length of stay (LOS).

RESULTS

Overall, 124 patients with a mean age at surgery ± SD of 3.59 ± 0.87 months and mean parietal bone thickness of 1.83 ± 0.38 mm were included in this study. Estimated blood loss (EBL) and EBL per kilogram were associated with parietal bone thickness 0.5 cm (ρ = 0.376, p < 0.001 and ρ = 0.331, p = 0.004; respectively) and 1.0 cm (ρ = 0.324, p = 0.007 and ρ = 0.245, p = 0.033; respectively) from the suture line. Patients with a thicker parietal bone 0.5 cm (OR 18.08, p = 0.007), 1.0 cm (OR 7.16, p = 0.031), and 1.5 cm (OR 7.24, p = 0.046) from the suture line were significantly more likely to have undergone transfusion when controlling for age, sex, and race. Additionally, parietal bone thickness was associated with hospital LOS (β 0.575, p = 0.019) when controlling for age, sex, and race. Patient age at the time of surgery was not independently associated with these perioperative outcomes.

CONCLUSIONS

Parietal bone thickness, but not age at the time of surgery, may predict perioperative outcomes including transfusion, EBL, and LOS. The need for transfusion and EBL were most significant for parietal bone thickness 0.5 cm to 1.5 cm from the suture line, within the anticipated area of suturectomy. For patients undergoing craniofacial surgery, parietal bone thickness may have important implications for anticipating the need for intraoperative transfusion and hospital LOS.

Predicting and comparing three corrective techniques for sagittal craniosynostosis

Sagittal synostosis is the most occurring form of craniosynostosis, resulting in calvarial deformation and possible long-term neurocognitive deficits. Several surgical techniques have been developed to correct these issues. Debates as to the most optimal approach are still ongoing. Finite element method is a computational tool that's shown to assist with the management of craniosynostosis. The aim of this study was to compare and predict the outcomes of three reconstruction methods for sagittal craniosynostosis. Here, a generic finite element model was developed based on a patient at 4 months of age and was virtually reconstructed under all three different techniques. Calvarial growth was simulated to predict the skull morphology and the impact of different reconstruction techniques on the brain growth up to 60 months of age. Predicted morphology was then compared with in vivo and literature data. Our results show a promising resemblance to morphological outcomes at follow up. Morphological characteristics between considered techniques were also captured in our predictions. Pressure outcomes across the brain highlight the potential impact that different techniques have on growth. This study lays the foundation for further investigation into additional reconstructive techniques for sagittal synostosis with the long-term vision of optimizing the management of craniosynostosis.

Long-Term Neurocognitive Outcomes of Spring-Assisted Surgery versus Cranial Vault Remodeling for Sagittal Synostosis

BACKGROUND

A long-term neurocognitive comparison of patients with sagittal synostosis who underwent spring-assisted surgery or cranial vault remodeling has not been performed.

METHODS

Patients with sagittal synostosis who underwent spring-assisted surgery or cranial vault remodeling were recruited from Wake Forest School of Medicine and Yale School of Medicine, respectively. Cognitive tests administered included an abbreviated intelligence quotient, academic achievement, and visuomotor integration. An analysis of covariance model compared cohorts controlling for demographic variables.

RESULTS

Thirty-nine spring-assisted surgery and 36 cranial vault remodeling patients were included in the study. No significant differences between cohorts were found with respect to age at surgery, sex, race, birth weight, family income, or parental education. The cranial vault cohort had significantly older parental age (p < 0.001), and mean age at testing for the spring cohort was significantly higher (p = 0.001). After adjusting for covariates, the cranial vault cohort had significantly higher verbal intelligence quotient (116.5 versus 104.3; p = 0.0024), performance intelligence quotient (109.2 versus 101.5; p = 0.041), and full-scale intelligence quotient (114.3 versus 103.2; p = 0.0032). When included patients were limited to intelligence quotients from 80 to 120, the cranial vault cohort maintained higher verbal (108.0 versus 100.4; p = 0.036), performance (104.5 versus 97.7; p = 0.016), and full-scale (107.6 versus 101.5; p = 0.038) intelligence quotients. The cranial vault cohort had higher visuomotor integration scores than the surgery group (111.1 versus 98.1; p < 0.001). There were no significant differences in academic achievement.

CONCLUSIONS

Sagittal synostosis patients who underwent cranial vault remodeling had higher intelligence quotient and visuomotor integration scores. There were no differences in academic achievement. Both cohorts had intelligence quotient scores at or above the normal range. Further studies are warranted to identify factors that may contribute to cognitive outcome differences.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Three-Dimensional Treatment Outcomes of a Virtual Helmet Design Protocol for Sagittal Strip Craniectomy

BACKGROUND

The helmet worn after sagittal strip craniectomy must be customized to the surgical procedure and the patient's anatomy to achieve optimal outcomes. This study compares three-dimensional head shape outcomes obtained from a novel virtual helmet design and from a traditional helmet design.

METHODS

Twenty-four patients underwent extended sagittal strip craniectomy performed by a single surgeon and helmet management performed by a single orthotist. Eleven patients constitute the traditional helmet group, with helmet design based on laser scans. Thirteen patients constitute the virtual helmet group, with helmet design based on an overlay of a three-dimensional volume rendering of a low-radiation protocol computed tomographic scan and three-dimensional photograph. Cephalic index and vertical height were recorded from three-dimensional photographs. Three-dimensional whole-head composite images were generated to compare global head shape outcomes to those of age-matched controls.

RESULTS

There was no significant difference in mean cephalic index between the virtual helmet group (83.70 ± 2.33) and controls (83.53 ± 2.40). The differences in mean cephalic index between the traditional helmet group (81.07 ± 3.37) and controls and in mean vertical height were each significant (p < 0.05). Three-dimensional analysis demonstrated normal biparietal and vertical dimensions in the virtual helmet group compared to controls. The traditional helmet group exhibited narrower biparietal dimension and greater vertical dimension compared to controls.

CONCLUSIONS

Traditional and virtual helmet protocols improved mean cephalic index, but the virtual helmet group yielded more consistent and greater change in cephalic index. The virtual helmet design protocol yielded three-dimensional outcomes similar to those of age-matched controls. Traditional helmet design yielded a narrower biparietal dimension and greater vertical dimension to the cranial vault compared to the virtual helmet group and controls.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Improved cephalic index following early cranial vault remodeling in patients with isolated nonsyndromic sagittal synostosis

OBJECTIVE

Isolated nonsyndromic sagittal synostosis (SS) is the most common form of craniosynostosis in children, accounting for approximately 60% of all craniosynostoses. The typical cranial measurement used to define and follow SS is the cephalic index (CI). Several surgical techniques have been suggested, but agreement on type and timing of surgery is lacking. This study aimed to evaluate the authors' institutional experience of surgically treating SS using a modified subtotal cranial vault remodeling technique in a population-based cohort. Special attention was directed toward the effect of patient age at time of surgery on long-term CI outcome.

METHODS

A retrospective analysis was conducted on all patients with isolated nonsyndromic SS who were surgically treated from 2003 to 2011. Data from electronic medical records were gathered. Eighty-two patients with SS were identified, 77 fulfilled inclusion criteria, and 72 had sufficient follow-up data and were included. CI during follow-up after surgery was investigated with ANOVA and a linear mixed model.

RESULTS

In total, 72 patients were analyzed, consisting of 16 females (22%) and 56 males (78%). The mean ± SD age at surgery was 4.1 ± 3.1 months. Blood transfusions were received by 81% of patients (26% intraoperatively, 64% postoperatively, 9% both). The mean ± SD time in the pediatric ICU was 1.1 ± 0.25 days, and the mean ± SD total hospital length of stay was 4.6 ± 2.0 days. No patient required reoperation. The mean ± SD CI increased from 69 ± 3 to 87 ± 5 for patients who underwent surgery before 45 days of age. Surgery resulted in a larger increase in CI for patients who underwent surgery at a younger age compared with older patients (p < 0.05, Tukey's HSD test). In the comparison of patients who underwent surgery before 45 days of age with patients who underwent surgery at 45-90, 90-180, and more than 180 days of age, the linear mixed model estimated a long-term loss of CI of 3.0, 5.5, and 7.4 points, respectively.

CONCLUSIONS

The modified subtotal cranial vault remodeling technique used in this study significantly improved CI in patients with SS. The best results were achieved when surgery was performed early in life.

Disappointing results of spring-assisted cranial vault expansion in patients with Crouzon syndrome presenting with sagittal synostosis

The aim of this study was to report on a single center's experience with spring-assisted cranial vault expansion (SAE) in patients with Crouzon syndrome and sagittal suture synostosis. Strip craniotomy with SAE has resulted in successful outcomes with low complication and revision rates in patients with isolated scaphocephaly. However, recent experience suggests that outcomes in patients with Crouzon syndrome and sagittal synostosis (SS) who undergo SAE are less favorable compared with the outcomes of those who undergo frontobiparietal (FBP) expansion. The authors reviewed both operations performed at a single center and noticed an upward expansion of the skull, which may be related to ventriculomegaly, with concurrent intracranial hypertension and poor aesthetic outcome. All patients diagnosed with Crouzon syndrome and SS who were treated with SAE required a revision FBP operation. Based on this outcome, the authors consider Crouzon syndrome a contraindication for correcting SS with springs.

Planning and Osteotomy Designs in the Correction of Single-Suture Craniosynostosis

BACKGROUND

Craniosynostosis is among the abnormalities that are more commonly encountered by craniofacial surgeons. Although the overall concepts for cranial vault remodeling are relatively simple, osteotomy designs and methods for calvarial rearrangement are highly varied. In this work, we present a summary of the known designs for correction of single-suture craniosynostosis.

METHODS

A review of the literature was performed of the more frequently used osteotomy designs for single-suture craniosynostosis, as well as their reported results and outcomes. Also reviewed are some of the current available approaches for the diagnosis and surgical planning for single-suture craniosynostosis.

RESULTS

There remains a diversity of techniques available for the reconstruction of each fused cranial suture. Certain osteotomy designs are reported in the literature and are used by craniofacial surgeons more frequently. Each has its own benefits and disadvantages, and there is a growing body of outcome data available to guide surgical decision-making. Regarding diagnosis and surgical planning, computed tomography with 3-dimensional reconstruction remains the diagnostic standard of care, and efforts are ongoing to develop and implement new diagnostic modalities like Black Bone MRI to reduce radiation exposure.

CONCLUSIONS

There has been ongoing evolution of the surgical techniques available to reconstruct single-suture craniosynostosis, leading to ever-improving patient outcomes.

Perioperative Outcomes in the Treatment of Isolated Sagittal Synostosis: Cranial Vault Remodeling Versus Spring Mediated Cranioplasty

BACKGROUND

Patients undergoing cranial expansion including spring-mediated cranioplasty (SMC) and cranial vault remodeling (CVR) receive costly and high acuity post-operative intensive care (ICU) given concerns over neurologic and hemodynamic vulnerability. The authors analyzed perioperative and post-operative events for patients presenting with sagittal craniosynostosis (CS) undergoing SMC and CVR in order to compare complication profiles.

METHODS

The authors performed a single center retrospective cohort study of patients undergoing SMC and CVR for the treatment of nonsyndromic, isolated sagittal CS from 2011 to 2018. Perioperative and post-operative factors were collected, focusing on hemodynamic instability and events necessitating ICU care. Mann-Whitney U and Fisher exact tests were used to compare data with significance defined as P < 0.05.

RESULTS

Among 106 patients, 65 (61%) underwent SMC and 41 (39%) CVR. All CVR patients received prophylactic whole blood transfusion at time of scalp incision. Acute blood loss anemia was the most common post-operative complication, prompting n = 6 (9.2%) and n = 7 (17.1%) blood transfusions in the SMC and CVR cohorts, respectively (P < 0.24). Hemodynamic instability requiring blood transfusion was rare, occurring post-operatively in n = 2 (3.1%) and n = 2 (4.9%) patients in the SMC and CVR cohorts, respectively (P < 0.64). Two patients in the CVR cohort exhibited new neurologic symptoms that self-resolved, compared to no patients in the SMC cohort (P < 0.15).

CONCLUSION

Despite differing degrees of operative invasiveness, post-operative hemodynamic and neurologic decompensation following CVR and SMC for isolated sagittal CS repair remains similarly rare. Indications necessitating post-operative intensive care are infrequent. Post-operative hemoglobin monitoring may enable early prediction for hemodynamic instability.

Comparison of 2 Sagittal Craniosynostosis Repair Techniques: Spring-Assisted Surgery Versus Endoscope-Assisted Craniectomy With Helmet Molding Therapy

INTRODUCTION

This study compares anthropometric outcomes of 2 sagittal synostosis repair techniques: spring-assisted surgery and endoscope-assisted craniectomy with molding helmet therapy.

METHODS

Patients undergoing spring-assisted surgery (n = 27) or endoscope-assisted craniectomy with helmet therapy (n = 40) at separate institutions were retrospectively reviewed. Pre- and 1-year postoperative computed tomography (CT) or laser scans were analyzed for traditional cranial index (CI), adjusted cranial index (aCI), and cranial vault volume (CVV). Nine patient-matched scans were analyzed for measurement consistency.

RESULTS

The spring-assisted group was older at both time points (P < .050) and spring-assisted group CVV was larger preoperatively and postoperatively (P < .01). However, the change in CVV did not differ between the groups (P = .210). There was no difference in preoperative CI (helmet vs spring: 70.1 vs 71.2, P = .368) between the groups. Postoperatively, helmet group CI (77.0 vs 74.3, P = .008) was greater. The helmet group also demonstrated a greater increase in CI (6.9 vs 3.1, P < .001). The proportion of patients achieving CI of 75 or greater was not significantly different between the groups (helmet vs spring: CI, 65% vs 52%, P = .370). There was no detectable bias in CI between matched CT and laser scans. Differences were identified between scan types in aCI and CVV measurements; subsequent analyses used corrected CVV and aCI measures for laser scan measures.

CONCLUSIONS

Both techniques had equivalent proportions of patients achieving normal CI, comparable effects on cranial volume, and similar operative characteristics. The study suggests that there may be greater improvement in CI in the helmet group. However, further research should be performed.

Spring-Assisted Surgery for Treatment of Sagittal Craniosynostosis

ABSTRACT

Craniosynostosis (CSS), the premature fusion of calvarial sutures, most commonly involves the sagittal suture. Cranial vault remodeling (CVR) is a traditional method of CSS correction. Minimally invasive methods are becoming widely accepted, including spring-assisted surgery (SAS). The equipment required for SAS is minimal therefore adaptable to resource challenged health systems. This paper outlines the experience of SAS in Moldova.A retrospective study was performed for patients treated with SAS for sagittal CSS from 2011 to 2018 in Moldova. Perioperative data were recorded including age, length of surgery, blood loss, volume transfused and length of stay. Four patients had pre- and post-operative computed tomography (CT) scans which were used to calculate changes in cephalic index, normative cephalic index, and intracranial volume.Thirteen patients underwent SAS. Diagnoses were made clinically and confirmed with CT. Mean age at surgery was 4.0 months, and length of surgery 62.7 minutes. All but one patient received a blood transfusion, as is standard of practice in Moldova. The mean length of post-operative recovery in ICU was 30.9 hours. No complications required surgical revision. Springs were removed after 4 to 5 months. All patients had a subjective improvement in scaphocephaly. Based on the available CT scans, an increase in cephalic index (7.3%), normative cephalic index (11.8%), and intracranial volume (38.1%) was observed. One patient underwent SAS at 11 months and required cranioplasty for asymmetry at the time of spring removal.SAS is a safe and cost-effective method of CSS correction that can be utilized in countries with limited health system resources.

Spring Cranioplasty: Incorporation Into Practice

OBJECTIVE

The aim of this paper is to discuss ways to incorporate spring-assisted cranioplasty into the surgical armamentarium for craniosynostosis.

BACKGROUND

Spring-assisted cranioplasty after cranial suturectomy for craniosynostosis was popularized in the literature by Dr Lauritzen in 2008 after reporting the results of the first 100 cases. Since that time, more craniofacial surgeons and neurological surgeons have incorporated this surgical technique for treatment of patients presenting with craniosynostosis. This paper will discuss how the team at Nationwide Children's Hospital has incorporated spring-assisted cranioplasty into the care of patients presenting with sagittal synostosis.

METHODS

In this article, the authors review our previous protocol for the treatment of children with sagittal synostosis prior to the introduction of spring cranioplasty. The authors then describe the impetus for incorporating spring-assisted cranioplasty for sagittal synostosis into our practice, and barriers we encountered during this implementation. The authors then discuss their current, comprehensive protocol for treating children with sagittal craniosynostosis. Finally, the authors review the expected and unexpected advantages that our craniofacial program has experienced as they implemented spring-assisted cranioplasty.

CONCLUSION

Incorporation of spring-assisted cranioplasty for sagittal synostosis offers an additional minimally invasive technique, which presents great advantages for many families, and is rewarding for both craniofacial and neurological surgeons.

Hope Springs Eternal: Insights Into the Durability of Springs to Provide Long-Term Correction of the Scaphocephalic Head Shape

Spring-mediated cranial vault expansion (SMC) has become a primary treatment modality at our institution to correct scaphocephalic head shape in the setting of isolated sagittal craniosynostosis (CS). Spring-mediated cranioplasty is associated with minimal procedural morbidity and reliable clinical efficacy, although long-term outcomes are not well elucidated. Herein we describe our institutional experience and lessons learned with SMC. We hypothesize that SMC performed in young infants offers durable scaphocephalic correction as measured by cephalic index (CI) at the 1, 3, and 5-year postoperative timepoints.Patients with isolated sagittal CS who underwent SMC at our institution during an 8-year period were retrospectively studied. The primary outcome measure was long-term head shape determined by CI at the 1, 3, and 5-year postoperative timepoints. Secondary outcomes included patient and spring factors associated with change in CI, including age and spring force. All statistical tests were 2-tailed with P < 0.05 denoting significance.In total, 88 patients underwent SMC at a median age of 3.3 months with a median preoperative CI 69 (interquartile range: [66, 71]). The postoperative CI increased to 73 [71, 76] at postoperative day 1. At 1 month, the CI increased by 8.6 to 77 (P < 0.0001) and appeared to reach a plateau at 3 months (76, [74, 78]) without further improvement (P < 0.10). At 5 years, CI remained stable without relapse (76, [75, 81], demonstrating an 8.9 increase from preoperative CI. Age at time of spring placement and change in CI were inversely related (P < 0.005). Total spring force directly correlated with increased change in postoperative CI at the 6-month postoperative timepoint (P < 0.02).In summary, SMC offers durable correction of scaphocephaly as measured by CI for patients with isolated sagittal CS at the 5-year postoperative timepoint. The cranial expansion observed 1-month post-spring implantation may serve as a proxy for long-term CI.

Outcomes of Endoscopic Versus Open Spring Assisted Surgery for Sagittal Craniosynostosis

Spring-assisted surgery (SAS) has been shown to be an effective technique for correction of isolated sagittal craniosynostosis in patients less than 6 months of age. At their institution, the authors adopted a minimally invasive technique in 2010, using a shorter incision and an endoscope. A retrospective chart review of 101 patients with isolated, nonsyndromic, sagittal craniosynostosis, who underwent SAS, was performed in order to compare perioperative and clinical outcomes of the open (n = 51) and minimally-invasive (n = 50) approaches. Surgeries were performed by 2 neurosurgeons and 3 plastic surgeons, between 2005 and 2018. The pre and postoperative cephalic indices were not significantly different in both groups. Minimally-invasive spring placement required a longer operative time than the open approach, with the mean minimally-invasive operative time at 65 minutes, compared to 53 minutes (P < 0.0001). Spring removal operative time was not significantly different, with the minimally-invasive operative time at 31 minutes versus 29 minutes (P = 0.48). There were no significant differences in major or minor complications when comparing the open and minimally-invasive approaches. In conclusion, both the open and the minimally-invasive SAS techniques are effective for early correction of isolated sagittal craniosynostosis, although the minimally-invasive approach requires a longer operative time for spring placement.

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes

Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization-using retrospective clinical spring measurements-was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young's modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application.

Quantification of Head Shape and Cranioplasty Outcomes: Six-compartment Volume Method Applied to Sagittal Synostosis

Supplemental Digital Content is available in the text.

Background:

Premature fusion of the sagittal (midline) suture between 2 parietal bones is the most common form of craniosynostosis. Surgical correction is mandated to improve head shape and to decrease the risk of raised intracranial pressure. This study evaluated the utility of 3-dimensional (3D) imaging to quantify the volumetric changes of surgical correction. Currently there is no standardized method used to quantify the outcomes of surgery for craniosynostosis, with the cranial index (width: length ratio) being commonly used.

Methods:

A method for quantification of head shape using 3D imaging is described in which the cranium is divided up into 6 compartments and the volumes of 6 compartments are quantified and analyzed. The method is size invariant, meaning that it can be used to assess the long-term postoperative outcomes of patients through growth. The method is applied to a cohort of sagittal synostosis patients and a normal cohort, and is used to follow up a smaller group of synostotic patients 1, 2, and 3 years postoperatively.

Results:

Statistical analysis of the results shows that the 6-compartment volume quantification method is more accurate in separating normal from synostotic patient head shapes than the cranial index.

Conclusions:

Spring-mediated cranioplasty does not return head shape back to normal, but results in significant improvements in the first year following surgery compared with the preoperative sagittal synostosis head shape. 3D imaging can be a valuable tool in assessing the volumetric changes due to surgery and growth in craniosynstosis patients.

An Overview of Modelling Craniosynostosis Using the Finite Element Method

Craniosynostosis is a medical condition caused by the early fusion of the cranial joint. The finite element method (FEM) is a computational technique that can answer a variety of "what if" questions in relation to the biomechanics of this condition. The aim of this study was to review the current literature that has used FEM to investigate the biomechanics of any aspect of craniosynostosis, being its development or its reconstruction. This review highlights that a relatively small number of studies (n = 10) has used FEM to investigate the biomechanics of craniosynostosis. Current studies set a good foundation for the future to take advantage of this method and optimize reconstruction of various forms of craniosynostosis.

Spring-Assisted Surgery in the Treatment of Complex Craniosynostosis

Multisutural nonsyndromic craniosynostosis is a rare group of malformations, whose frequency has been reported between 3% and 7% of all craniosynostosis. The clinical diagnosis can be difficult and computed tomography is usually required. Surgical treatment is challenging and staged procedures are performed in up to 80% of patients. The aim of the present study was to determine the reoperation rate and to evaluate the surgical outcomes by measuring intracranial volume (ICV) preoperatively and at follow-up, and comparing it to a control group. Perioperative variables and reoperation rate were recorded. Fifty-one patients presented with a complex pattern of synostosis without a recognizable syndrome (5% of cases of total patients evaluated). Fifteen patients have been treated with spring-assisted surgery, either alone or in combination with a foreheadplasty. The mean follow-up was 6.2 years. The mean preoperative ICV of the patients was smaller, but not significantly, than in the normal population (P = 0.13). Postoperatively, the mean ICV was similar to that of the control group at 1 year (P = 0.92), while at 3 years it was appreciably smaller, although not significantly different (P = 0.06). Five patients (33%) went through a secondary skull expansion for either raised intracranial pressure or cosmetic reasons. Spring-assisted surgery seems to temporarily expand ICV in children with complex synostosis and lower the reoperation rate, thus reducing the need for a second procedure. A longer follow-up would be necessary to further investigate the effects of springs over time.

Intraoperative and postoperative complications in the surgical treatment of craniosynostosis: minimally invasive versus open surgical procedures

OBJECTIVE To compare minimally invasive endoscopic and open surgical procedures, to improve informed consent of parents, and to establish a baseline for further targeted improvement of surgical care, this study evaluated the complication rate and blood transfusion rate of craniosynostosis surgery in our department. METHODS A prospective complication registration database that contains a consecutive cohort of all pediatric neurosurgical procedures in the authors' neurosurgical department was used. All pediatric patients who underwent neurosurgical treatment for craniosynostosis between February 2004 and December 2014 were included. In total, 187 procedures were performed, of which 121 were endoscopically assisted minimally invasive procedures (65%). Ninety-three patients were diagnosed with scaphocephaly, 50 with trigonocephaly, 26 with plagiocephaly, 3 with brachycephaly, 9 with a craniosynostosis syndrome, and 6 patients were suffering from nonsyndromic multisutural craniosynostosis. RESULTS A total of 18 complications occurred in 187 procedures (9.6%, 95% CI 6.2-15), of which 5.3% (n = 10, 95% CI 2.9-10) occurred intraoperatively and 4.2% (n = 8, 95% CI 2.2-8.2) occurred postoperatively. In the open surgical procedure group, 9 complications occurred: 6 intraoperatively and 3 postoperatively. In the endoscopically assisted procedure group, 9 complications occurred: 4 intraoperatively and 5 postoperatively. Blood transfusion was needed in 100% (n = 66) of the open surgical procedures but in only 21% (n = 26, 95% CI 15-30) of the endoscopic procedures. One patient suffered a transfusion reaction, and 6 patients suffered infections, only one of which was a surgical site infection. A dural tear was the most common intraoperative complication that occurred (n = 8), but it never led to postoperative sequelae. Intraoperative bleeding from a sagittal sinus occurred in one patient with only minimal blood loss. There were no deaths, permanent morbidity, or neurological sequelae. CONCLUSIONS Complications during craniosynostosis surgery were relatively few and minor and were without permanent sequelae in open and in minimally invasive procedures. The blood transfusion rate was significantly reduced in endoscopic procedures compared with open procedures.

Assessment of spring cranioplasty biomechanics in sagittal craniosynostosis patients

OBJECTIVE Scaphocephaly secondary to sagittal craniosynostosis has been treated in recent years with spring-assisted cranioplasty, an innovative approach that leverages the use of metallic spring distractors to reshape the patient skull. In this study, a population of patients who had undergone spring cranioplasty for the correction of scaphocephaly at the Great Ormond Street Hospital for Children was retrospectively analyzed to systematically assess spring biomechanical performance and kinematics in relation to spring model, patient age, and outcomes over time. METHODS Data from 60 patients (49 males, mean age at surgery 5.2 ± 0.9 months) who had received 2 springs for the treatment of isolated sagittal craniosynostosis were analyzed. The opening distance of the springs at the time of insertion and removal was retrieved from the surgical notes and, during the implantation period, from planar radiographs obtained at 1 day postoperatively and at the 3-week follow-up. The force exerted by the spring to the patient skull at each time point was derived after mechanical testing of each spring model-3 devices with the same geometry but different wire thicknesses. Changes in the cephalic index between preoperatively and the 3-week follow-up were recorded. RESULTS Stiffer springs were implanted in older patients (p < 0.05) to achieve the same opening on-table as in younger patients, but this entailed significantly different-higher-forces exerted on the skull when combinations of stiffer springs were used (p < 0.001). After initial force differences between spring models, however, the devices all plateaued. Indeed, regardless of patient age or spring model, after 10 days from insertion, all the devices were open. CONCLUSIONS Results in this study provide biomechanical insights into spring-assisted cranioplasty and could help to improve spring design and follow-up strategy in the future.

Cranial bone structure in children with sagittal craniosynostosis: Relationship with surgical outcomes

BACKGROUND

While spring-assisted cranioplasty has become a widespread technique to correct scaphocephaly in children with sagittal synostosis, predicting head shape changes induced by the gradual opening of the springs remains challenging. This study aimed to explore the role of cranial bone structure on surgical outcomes.

METHODS

Patients with isolated sagittal synostosis undergoing spring-assisted cranioplasty at GOSH (London, UK) were recruited (n = 18, age: 3-8 months). Surgical outcome was assessed by the change in cephalic index measured on 3D head scans acquired before spring insertion and after their removal using a 3D handheld scanner. Parietal bone samples routinely discarded during spring-assisted cranioplasty were collected and scanned using micro-computed tomography. From visual assessment of such scans, bone structure was classified into one- or three-layered, the latter indicating the existence of a diploë cavity. Bone average thickness, volume fraction and surface density were computed and correlated with changes in cephalic index.

RESULTS

Cephalic index increased for all patients (p < 0.001), but individual improvement varied. Although the patient age and treatment duration were not significantly correlated with changes in cephalic index, bone structural parameters were. The increase of cephalic index was smaller with increasing bone thickness (Pearson's r = -0.79, p < 0.001) and decreasing bone surface density (r = 0.77, p < 0.001), associated with the three-layered bone structure.

CONCLUSIONS

Variation in parietal bone micro-structure was associated with the magnitude of head shape changes induced by spring-assisted cranioplasty. This suggests that bone structure analysis could be a valuable adjunct in designing surgical strategies that yield optimal patient-specific outcomes.

Three-dimensional changes in head shape after extended sagittal strip craniectomy with wedge ostectomies and helmet therapy

OBJECTIVE Outcome studies for sagittal strip craniectomy have largely relied on the 2D measure of the cephalic index (CI) as the primary indicator of head shape. The goal of this study was to measure the 2D and 3D changes in head shape that occur after sagittal strip craniectomy and postoperative helmet therapy. METHODS The authors performed a retrospective review of patients treated with sagittal strip craniectomy at their institution between January 2012 and October 2015. Inclusion criteria were as follows: 1) isolated sagittal synostosis; 2) age at surgery < 200 days; and 3) helmet management by a single orthotist. The CI was calculated from 3D images. Color maps and dot maps were generated from 3D images to demonstrate the regional differences in the magnitude of change in head shape over time. RESULTS Twenty-one patients met the study inclusion criteria. The mean CI was 71.9 (range 63.0-77.9) preoperatively and 81.1 (range 73.0-89.8) at the end of treatment. The mean time to stabilization of the CI after surgery was 57.2 ± 32.7 days. The mean maximum distances between the surfaces of the preoperative and 1-week postoperative and between the surfaces of the preoperative and end-of-treatment 3D images were 13.0 ± 4.1 mm and 24.71 ± 6.83 mm, respectively. The zone of maximum change was distributed equally in the transverse and vertical dimensions of the posterior vault. CONCLUSIONS The CI normalizes rapidly after sagittal strip craniectomy (57.2 days), with equal distribution of the change in CI occurring before and during helmet therapy. Three-dimensional analysis revealed significant vertical and transverse expansion of the posterior cranial vault. Further studies are needed to assess the 3D changes that occur after other sagittal strip craniectomy techniques.

Nonsyndromic Craniosynostosis and Deformational Head Shape Disorders

This article provides an overview of etiology, epidemiology, pathology, diagnosis, and treatment of nonsyndromic craniosynostosis, including sagittal, metopic, coronal, lambdoid, and complex synostosis. Detailed discussion is presented regarding indications for surgical intervention and management options, including frontoorbital advancement, cranial vault reconstruction, endoscopic strip craniectomy, spring-assisted strip craniectomy, and cranial vault distraction osteogenesis. Deformational plagiocephaly is also presented with treatment options including repositioning, physical therapy, and helmet therapy.