Surgical treatment of single-suture craniosynostosis: an argument for quantitative methods to evaluate cosmetic outcomes

Comparison of Morphometric Outcomes following Open Posterior Expansion versus Endoscopic Strip Craniectomy for Sagittal Synostosis

BACKGROUND

Open middle and posterior cranial vault expansion (OPVE) or endoscopic (ES) strip craniectomy are two surgical techniques for normalization of head shape in isolated sagittal synostosis. This study aims to compare 2-year cranial morphometrics after these two approaches.

METHODS

The authors performed morphometric analysis on preoperative [time (T) 0], immediately postoperative (T1), and 2-year (T2) postoperative computed tomographic scans of patients who underwent OPVE or ES before 4 months of age. Perioperative data and morphometrics were compared between the two groups and age-matched controls.

RESULTS

Nineteen patients were included in the ES cohort, 19 age-matched patients were included in the OPVE cohort, and 57 were included as controls. Median surgery time and blood transfusion volume were less for the ES approach (118 minutes and 0 cc, respectively) compared with OPVE (204 minutes and 250 cc, respectively). Anthropometric measurements after OPVE were closer in normal controls at T1 compared with ES, but the skull shapes were comparable at T2. In the midsagittal plane, anterior vault was higher after OPVE at T2 compared with both ES and controls, but the posterior length was shorter and closer to controls than in the ES cohort. Cranial volumes were like controls for both cohorts at T2. There was no difference in complication rate.

CONCLUSIONS

Both OPVE and ES techniques result in normalization of cranial shape in patients with isolated sagittal synostosis after 2 years with minimal morphometric differences. Family decision-making between the two approaches should be based on age at presentation, avoidance of blood transfusion, scar pattern, and availability of helmet molding and not on expected outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

CranioRate: An Image-Based, Deep-Phenotyping Analysis Toolset and Online Clinician Interface for Metopic Craniosynostosis

BACKGROUND

The diagnosis and management of metopic craniosynostosis involve subjective decision-making at the point of care. The purpose of this work was to describe a quantitative severity metric and point-of-care user interface to aid clinicians in the management of metopic craniosynostosis and to provide a platform for future research through deep phenotyping.

METHODS

Two machine-learning algorithms were developed that quantify the severity of craniosynostosis-a supervised model specific to metopic craniosynostosis [Metopic Severity Score (MSS)] and an unsupervised model used for cranial morphology in general [Cranial Morphology Deviation (CMD)]. Computed tomographic (CT) images from multiple institutions were compiled to establish the spectrum of severity, and a point-of-care tool was developed and validated.

RESULTS

Over the study period (2019 to 2021), 254 patients with metopic craniosynostosis and 92 control patients who underwent CT scanning between the ages of 6 and 18 months were included. CT scans were processed using an unsupervised machine-learning based dysmorphology quantification tool, CranioRate. The average MSS was 0.0 ± 1.0 for normal controls and 4.9 ± 2.3 ( P < 0.001) for those with metopic synostosis. The average CMD was 85.2 ± 19.2 for normal controls and 189.9 ± 43.4 ( P < 0.001) for those with metopic synostosis. A point-of-care user interface (craniorate.org) has processed 46 CT images from 10 institutions.

CONCLUSIONS

The resulting quantification of severity using MSS and CMD has shown an improved capacity, relative to conventional measures, to automatically classify normal controls versus patients with metopic synostosis. The authors have mathematically described, in an objective and quantifiable manner, the distribution of phenotypes in metopic craniosynostosis.

Cosmetic satisfaction and patient-reported outcomes following surgical treatment of single-suture craniosynostosis: a systematic review

PURPOSE

This study provides a systematic review on cosmetic satisfaction and other patient-reported outcomes (PROMs) of patients who underwent surgical treatment of SSC.

METHODS

A systematic review of all articles published from inception to 1 June 2022 was performed. Articles were included if they reported on subjective assessment of cosmetic satisfaction or other PROMs by patients or their families using questionnaires or interviews.

RESULTS

Twelve articles, describing 724 surgical treatments of SSC, met the inclusion criteria. Cosmetic satisfaction was evaluated in the following ways: 1) use of the VAS score, binary questions or a 5-point scale to rate general, facial or skull appearance; 2) use of an aesthetic outcome staging in which personal opinion was added to the treating surgeon's opinion; and 3) use of an evaluation of anatomical proportions of the skull and face. A trend towards an overall improvement in cosmetic satisfaction following surgical treatment of SSC was observed. Reported PROMs included general health, socioeconomic status, patients' and their families' rating of the normalcy and noticeability of their appearance and how much this bothered them, and patients' answers to the Youth Quality of Life with Facial Differences (YQOL-FD) questionnaire. No clear overall trend of the reported PROMs was identified.

CONCLUSION

This systematic review illuminates that there is a wide variation in outcomes for evaluating cosmetic satisfaction and other PROMs of patients who underwent surgical treatment of SSC, suggesting that further research is needed to develop an inclusive and uniform approach to assess these outcomes.

Cognitive performance in preschoolers with non-syndromic craniosynostosis undergoing surgery: A comparison with typically developing children

This study aimed to determine the cognitive profile of preschool children undergoing surgery to correct non-syndromic craniosynostosis, compare them with typically developing children, and analyze possible cognitive deficits in the most prevalent subtypes: sagittal and unicoronal. Thirty-one children aged 3 years to 5 years and 11 months with non-syndromic craniosynostosis (11 sagittal, 9 unicoronal, 4 metopic, 3 lambdoid, 4 multisutural) who underwent surgery were compared with thirty-one typically developing children. The Wechsler Preschool and Primary Scale of Intelligence-Third Edition (WPPSI-III) was used to assess cognitive function. Children with non-syndromic craniosynostosis scored below the typically developing children in the Verbal Intelligence Quotient (VIQ) and Full-Scale Intelligence Quotient (FISQ). When specific subtypes were compared, children with sagittal synostosis scored similarly to the typically developing children; in contrast, children with unicoronal synostosis had lower performance in the Processing Speed Quotient and FISQ. The proportion of participants scoring below one standard deviation on the VIQ, General Language Composite, and FISQ was greater in the non-syndromic craniosynostosis group. This study supports the finding that children with non-syndromic craniosynostosis, particularly those with unicoronal synostosis, have more cognitive difficulties than those with normal development. Assessing cognition at preschool age in children with non-syndromic craniosynostosis is important in order to detect difficulties before they become more apparent at school age.

Microvascular decompression for trigeminal neuralgia caused by persistent trigeminal artery associated with craniosynostosis: a case report

BACKGROUND

Persistent trigeminal artery (PTA) is a rare arterial anastomosis between the basilar artery (BA) and internal carotid artery (ICA). It plays an indispensable role in a number of neurological disorders, including trigeminal neuralgia (TN).

CASE PRESENTATION

We report a unique case of a 58-year-old Han female patient with TN caused by PTA associated with craniosynostosis. Preoperative three-dimensional time-of-flight (3D-TOF) magnetic resonance (MR) and 3D constructive inference in steady state (3D-CISS) imaging showed that the PTA run though Meckel's cave. Complete pain relief was immediately achieved after microvascular decompression (MVD), without facial numbness and other complications. No recurrence was recorded at the 1-year follow up.

CONCLUSIONS

Microvascular decompression is a feasible option for the treatment of complex TN combined with other abnormalities. For patients deemed suitable for percutaneous balloon compression, PTA should be ruled out. Preoperative 3D-TOF and 3D-CISS MR imaging were essential to identify PTA neurovascular conflicts.

Modified Cephalic Index Measured at Superior Levels of the Cranium Revealed Improved Correction With Helmet Therapy for Patients With Sagittal Suture Craniosynostosis

OBJECTIVE

Historically, studies have shown that cranial remolding therapy improves surgical correction and protects against regression for patients with sagittal suture craniosynostosis. This study aimed to define the most responsive cranial height for measuring cephalic index (CI) following cranial remolding therapy for infants with sagittal suture craniosynostosis.

METHODS

The authors performed a retrospective analysis of data between January 2018 and August 2019. The outcomes measured were CI-3 (level of glabella) through CI-7 (superior to eurions), where each value was defined as the width at levels 3 through 7 divided by the length at level 3. Differences between baseline- and post-treatment measurements were assessed using a 5 × 2 repeated measures analysis of variance.

RESULTS

Data from thirty-four patients (19 males, 15 females, and mean age 2.79 months) were analyzed. Mean treatment duration was 4.59 ± 1.86 months. There was a significant increase between baseline and posttreatment measurements (baseline: 72.60% ± 0.70%, post: 76.30% ± 0.80%; F1,33 = 27.74, P < 0.001). The interaction effect for CI level * baseline-post was also significant (F1.43,47.16 = 6.75, P = 0.006). Post hoc analyses revealed the posttreatment measures were significantly greater than baseline measures at every CI level. The magnitude of the measured differences systematically decreased from CI-7 to CI-3, with a greater effect size at the most superior level (ie CI-7) of 0.961 compared to 0.778 at the traditional level (ie CI-3).

CONCLUSIONS

The CI measurement at level 7 demonstrated the greatest responsiveness to treatment, whereas the traditional CI measurement taken at level 3, the current standard, proved the least responsive.

Isolation and Characterization of Human Suture Mesenchymal Stem Cells In Vitro

BACKGROUND AND OBJECTIVES

Cranial sutures play a critical role in adjustment of skull development and brain growth. Premature fusion of cranial sutures leads to craniosynostosis. The aim of the current study was to culture and characterize human cranial suture mesenchymal cells in vitro.

METHODS

The residual skull tissues, containing synostosed or contralateral suture from three boys with right coronal suture synostosis, were used to isolate the suture mesenchymal cells. Then, flow cytometry and multilineage differentiation were performed to identify the typical mesenchymal stem cell (MSC) properties. Finally, we used quantitative real-time polymerase chain reaction (RT-PCR) to detect the mRNA expression of osteogenesis and stemness related genes.

RESULTS

After 3 to 5 days in culture, the cells migrated from the tissue explants and proliferated parallelly or spirally. These cells expressed typical MSC markers, CD73, CD90, CD105, and could give rises to osteocytes, adipocytes and chondrocytes. RT-PCR showed relatively higher levels of Runx2, osteocalcin and FGF2 in the fused suture MSCs than in the normal cells. However, BMP3, the only protein of BMP family that inhibits osteogenesis, reduced in synostosed suture derived cells. The expression of effector genes remaining cell stemness, including Bmi1, Gli1 and Axin2, decreased in the cells migrated from the affected cranial sutures.

CONCLUSIONS

The MSCs from prematurely occlusive sutures overexpressed osteogenic related genes and down-regulated stemness-related genes, which may further accelerate the osteogenic differentiation and suppress the self-renewal of stem cells leading to craniosynostosis.

On-site CAD templates reduce surgery time for complex craniostenosis repair in infants: a new method

INTRODUCTION

The surgical correction of craniostenosis in children is a time-consuming and taxing procedure. To facilitate this procedure, especially in infants with complex craniostenosis, we refined the computer-aided design and manufacturing technique (CAD/CAM) based on computed tomography (CT)-generated DICOM data. We used cutting guides and molding templates, which allowed the surgeon to reshape and fixate the supraorbital bar extracorporeally on a side table and to control the intracorporal fit without removing the template.

METHOD AND PATIENTS

To compare our traditional concept with the possibility of preoperative virtual planning (PVP) technique, the surgical treatment and courses of 16 infants with complex craniostenosis following fronto-orbital advancement (FOA) (age range 8-15 months) were analyzed in two groups (group 1: traditional, control group n = 8, group 2: CAD/CAM planned, n = 8).

RESULTS

While in both groups, the head accurately reshaped postoperatively during the follow-up; the CAD group 2 showed a significantly shorter operating time with a mean of 4 h 25 min compared with group 1 with a mean of 5 h 37 min (p = 0.038). Additionally, the CAD group 2 had a significantly lower volume of blood loss (380 ml vs. 575 ml mean, p = 0.047), lower blood transfusion volume (285 ml vs. 400 ml mean, p = 0.108), lower fresh frozen plasma (FFP) volume (140 ml vs. 275 ml mean, p = 0.019), shorter stay in the pediatric intensive care unit (PICU) (3 vs. 5 days mean (p = 0.002), and shorter total length of hospital stay (6 days vs. 8 days mean, p = 0.002).

CONCLUSION

CAD/CAM cutting guides and templates offer optimizing operative efficiency, precision, and accuracy in craniostenosis surgery in infants. As shown in this single-center observational study, the use of on-site templates significantly accelerates the reconstruction of the bandeau. The virtual 3D planning technique increases surgical precision without discernible detrimental effects.

The economic impact of open versus endoscope-assisted craniosynostosis surgery

OBJECTIVE

Open and endoscope-assisted repair are surgical options for sagittal craniosynostosis, with limited research evaluating each technique's immediate and long-term costs. This study investigates the cost-effectiveness of open and endoscope-assisted repair for single, sagittal suture craniosynostosis.

METHODS

The authors performed a retrospective cohort study of patients undergoing single, sagittal suture craniosynostosis repair (open in 17 cases, endoscope-assisted in 16) at less than 1 year of age at Monroe Carell Jr. Children's Hospital at Vanderbilt (MCJCHV) between August 2015 and August 2017. Follow-up data were collected/analyzed for 1 year after discharge. Surgical and follow-up costs were derived by merging MCJCHV financial data with each patient's electronic medical record (EMR) and were adjusted for inflation using the healthcare Producer Price Index. Proxy helmet costs were derived from third-party out-of-pocket helmet prices. To account for variable costs and probabilities, overall costs were calculated using TreeAge tree diagram software.

RESULTS

Open repair occurred in older patients (mean age 5.69 vs 2.96 months, p < 0.001) and required more operating room time (median 203 vs 145 minutes, p < 0.001), more ICU days (median 3 vs 1 day, p < 0.001), more hospital days (median 4 vs 1 day, p < 0.001), and more frequently required transfusion (88% vs 6% of cases). Compared to patients who underwent open surgery, patients who underwent endoscopically assisted surgery more often required postoperative orthotic helmets (100% vs 6%), had a similar number of follow-up clinic visits (median 3 vs 3 visits, p = 0.487) and CT scans (median 3 vs 2 scans), and fewer emergency department visits (median 1 vs 3 visits). The TreeAge diagram showed that, overall, open repair was 73% more expensive than endoscope-assisted repair ($31,314.10 vs $18,081.47). Sensitivity analysis identified surgical/hospital costs for open repair (mean $30,475, SEM $547) versus endoscope-assisted repair (mean $13,746, SEM $833) (p < 0.001) as the most important determinants of overall cost. Two-way sensitivity analysis comparing initial surgical/hospital costs confirmed that open repair remains significantly more expensive under even worst-case initial repair scenarios ($3254.81 minimum difference). No major surgical complications or surgical revisions occurred in either cohort.

CONCLUSIONS

The results of this study suggest that endoscope-assisted craniosynostosis repair is significantly more cost-effective than open repair, based on markedly lower costs and similar outcomes, and that the difference in initial surgical/hospital costs far outweighs the difference in subsequent costs associated with helmet therapy and outpatient management, although independent replication in a multicenter study is needed for confirmation due to practice and cost variation across institutions. Longer-term results will also be needed to examine whether cost differences are maintained.

Current Trends in Management of Nonsyndromic Unilateral Coronal Craniosynostosis: A Cross-sectional Survey

Background

Although the natural history of nonsyndromic unilateral coronal craniosynostosis has been extensively described, optimal management remains controversial due to lack of Level 1 evidence. This study aims to assess the current state of practice among craniofacial surgeons.

Methods

Ninety-four craniofacial surgeons were approached to complete a survey consisting of 15 questions. Data were collected assessing surgeons' primary surgical indication, timing of intervention, preoperative imaging, and choice of technique for patients presenting with nonsyndromic unilateral coronal craniosynostosis. Choice of technique and timing of intervention in case of recurrence were also investigated.

Results

After 5 mailings, the response rate was 61%. The combination of both appearance and raised intracranial pressure was the primary indication for treatment for 73.2% of surgeons. Preoperative CT scan of the skull was "always" performed by 70.1% of respondents. Open surgical management was most commonly performed at 8-10 months of age (38.6%). Bilateral frontal craniectomy with remodeling of the supraorbital bandeau and frontal bone was the most common choice of procedure (84.2%). In case of mild to moderate and moderate to severe recurrences at 1 year of age, 89.5% and 47.4% of surgeons opted for conservative management, respectively. Optimal timing for repeat cranioplasty was after 4 years of age (65.5%). Overall, 43.4% quoted lack of evidence as the greatest obstacle to clinical decision-making when dealing with unilateral synostosis.

Conclusion

This survey exposes the lack of consensus and the disparity of opinion among craniofacial surgeons regarding the management of nonsyndromic coronal synostosis, particularly in the setting of recurrence.

Comparing Cephalic Index and Midsagittal Vector Analysis in Assessing Morphology in Sagittal Synostosis: A CT-Based Morphometric Analysis

INTRODUCTION

Assessment of cranial dysmorphism in sagittal synostosis is often subjective but objective measures can be applied. These include cephalic index (CI) and midsagittal vector analysis (MSVA).

OBJECTIVE

To assess discriminant validity, construct validity, and responsiveness of CI and MSVA measured from computed tomography (CT) in patients with sagittal synostosis.

METHODS

Patients with nonsyndromic isolated sagittal synostosis with complete preoperative (n = 30) and postoperative (n = 13) CT data were included. Age-matched control group (n = 24) comprised of normocephalic patients who underwent CT for reasons related to trauma.

OUTCOME MEASURES

Retrospective CT evaluation of CI and MSVA was conducted and correlated with a dysmorphism numeric rating scale (D-NRS) that measured surgeon-rated severity of sagittal synostosis. Responsiveness of CI and MSVA was evaluated using dysmorphism global rating of change (D-GRC).

RESULTS

Thirty patients with sagittal synostosis were demographically similar to 24 normocephalic patients. The difference in CI and MSVA was statistically significant between normocephalic and scaphocephalic patients. Cephalic index had a good correlation with D-NRS (r = -0.665, ρ = -0.667), but not with MSVA (r = 0.250, ρ = 0.203). Change in CI (r = 0.738, ρ = 0.657) was well correlated with D-GRC, but not with MSVA (r = -0.409, ρ = -0.301).

CONCLUSION

Cephalic index appears to quantify the severity of sagittal synostosis better than MSVA. Cephalic index also has better responsiveness than MSVA to measure a reduction in severity of disease; however, MSVA is a better descriptive craniometric measurement. Midsagittal vector analysis was able to quantify the shift in morphology in sagittal synostosis following surgical treatment.

Posterior Vault Distraction Osteogenesis in Nonsyndromic Patients: An Evaluation of Indications and Safety

PURPOSE

The purpose of this study was to evaluate the indications, safety, and short-term outcomes of posterior vault distraction osteogenesis (PVDO) in patients with no identified acrocephalosyndactyly syndrome (study) and to compare those to a syndromic cohort (controls).

METHODS

Demographic and perioperative data were recorded and compared across the study and control groups for those who underwent PVDO between January 2009 and December 2016. Univariate analysis was conducted using χ and Fisher exact tests for categorical variables, and Mann-Whitney U test for continuous variables.

RESULTS

Sixty-three subjects were included: 19 in the nonsyndromic cohort, 44 in the syndromic cohort. The cohorts had similar proportion of subjects exhibiting pansynostosis (42.1% of nonsyndromic versus 36.4% of syndromic, P = 0.667). The nonsyndromic cohort was significantly older (4.04 ± 3.66 years versus 2.55 ± 3.34 years, P = 0.046) and had higher rate of signs of raised intracranial pressure (68.4% versus 25.0%, P = 0.001) than the syndromic cohort. There was no significant difference in perioperative variables or rate of complications (P > 0.05). The mean total advancement distance achieved was similar, 27 ± 6 mm in the nonsyndromic versus 28 ± 8 mm in the syndromic cohort (P = 0.964). All nonsyndromic subjects with signs of raised intracranial pressure demonstrated improvement at an average follow-up of 22 months.

CONCLUSION

As in the syndromic patient, PVDO is a safe and, in the short-term, effective modality for cranial vault expansion in the nonsyndromic patient. The benefits and favorable perioperative profile of PVDO may therefore be extended to patient populations other than those with syndromic craniosynostosis.

Surgical Correction of Metopic Craniosynostosis: A 3-D Photogrammetric Analysis of Cranial Vault Outcomes

OBJECTIVE

To evaluate 3-dimensional (3-D) photogrammetry as a tool for assessing the postoperative head shape of patients who had undergone cranial vault remodeling for metopic synostosis.

DESIGN

We prospectively analyzed images of patients with metopic craniosynostosis who had undergone anterior cranial vault remodeling and age-matched controls. To ensure standardized facial orientation, each 3-D image was positioned to "best fit" the preoperative face by aligning 6 soft tissue landmarks. Forehead measurements were taken from a standardized position behind the surface of the face to landmarks placed in a ray configuration across the forehead.

SETTING

Academic teaching hospital.

PATIENTS, PARTICIPANTS

Thirteen pediatric patients with metopic craniosynostosis who had undergone anterior cranial vault remodeling and age-matched controls.

INTERVENTIONS

Images were taken preoperatively, immediately postoperatively, and over 1-year postoperatively.

MAIN OUTCOME MEASURES

Forehead contours preoperatively and postoperatively, with statistics performed using a multivariate analysis of variance shape analysis.

RESULTS

Mean postoperative follow-up was 1.8 (0.6) years. The average distance from the origin to forehead landmarks was 55.1 (3.4) mm preoperatively, 59.3 (0.7) mm immediate postoperatively, 59.1 (1.0) mm 1-year postoperatively, and 59.4 (0.6) mm in controls. Postoperative metopic forehead contours varied significantly from preoperative contours ( P < .01), while there was no statistical difference between the 2 postoperative time points ( P = .70). One-year postoperative patients were not significantly different from their age-matched controls ( P > .99).

CONCLUSIONS

Preoperative metopic forehead contours varied significantly from postoperative contours. Cranial reconstructions approximated the foreheads of normal controls, and reconstructions were stable at more than 1-year follow-up.

Endoscopy-assisted craniosynostosis surgery followed by helmet therapy

Background

Surgical methods to treat craniosynostosis have evolved from a simple strip craniectomy to a diverse spectrum of partial or complete cranial vault remodeling with excellent results but often with high comorbidity. Therefore, minimal invasive craniosynostosis surgery has been explored in the last few decades. The main goal of minimal invasive craniosynostosis surgery is to reduce the morbidity and invasiveness of classical surgical procedures, with equal long-term results, both functional as well as cosmetic.

Methods

To reach these goals, we adopted endoscopy-assisted craniosynostosis surgery (EACS) supplemented with helmet molding therapy in 2005.

Results

We present in detail our surgical technique used for scaphocephaly, trigonocephaly, plagiocephaly, complex multisutural, and syndromic cases of craniosynostosis.

Conclusions

We conclude that EACS with helmet therapy is a safe and suitable treatment option for any type of craniosynostosis, if performed at an early age, preferably around 3 months of age.

Statistical shape modelling to aid surgical planning: associations between surgical parameters and head shapes following spring-assisted cranioplasty

PURPOSE

Spring-assisted cranioplasty is performed to correct the long and narrow head shape of children with sagittal synostosis. Such corrective surgery involves osteotomies and the placement of spring-like distractors, which gradually expand to widen the skull until removal about 4 months later. Due to its dynamic nature, associations between surgical parameters and post-operative 3D head shape features are difficult to comprehend. The current study aimed at applying population-based statistical shape modelling to gain insight into how the choice of surgical parameters such as craniotomy size and spring positioning affects post-surgical head shape.

METHODS

Twenty consecutive patients with sagittal synostosis who underwent spring-assisted cranioplasty at Great Ormond Street Hospital for Children (London, UK) were prospectively recruited. Using a nonparametric statistical modelling technique based on mathematical currents, a 3D head shape template was computed from surface head scans of sagittal patients after spring removal. Partial least squares (PLS) regression was employed to quantify and visualise trends of localised head shape changes associated with the surgical parameters recorded during spring insertion: anterior-posterior and lateral craniotomy dimensions, anterior spring position and distance between anterior and posterior springs.

RESULTS

Bivariate correlations between surgical parameters and corresponding PLS shape vectors demonstrated that anterior-posterior (Pearson's [Formula: see text]) and lateral craniotomy dimensions (Spearman's [Formula: see text]), as well as the position of the anterior spring ([Formula: see text]) and the distance between both springs ([Formula: see text]) on average had significant effects on head shapes at the time of spring removal. Such effects were visualised on 3D models.

CONCLUSIONS

Population-based analysis of 3D post-operative medical images via computational statistical modelling tools allowed for detection of novel associations between surgical parameters and head shape features achieved following spring-assisted cranioplasty. The techniques described here could be extended to other cranio-maxillofacial procedures in order to assess post-operative outcomes and ultimately facilitate surgical decision making.

[3D printing in neurosurgery: a specific model for patients with craniosynostosis]

INTRODUCTION

Craniosynostosis is a rare condition and requires a personalised surgical approach, which is why we consider the use of 3D printed models beneficial in the surgical planning of this procedure.

MATERIAL AND METHODS

Acrylonitrile butadiene styrene plastic skull models were designed and printed from CT images of patients between 3 and 6 months of age with craniosynostosis of different sutures. The models were used to simulate surgical procedures.

RESULTS

Four models of four patients with craniosynostosis were produced: two with closure of the metopic suture and two with sagittal suture closure. The mean age of the patients was 5 months (3-6m) and the mean duration of the surgery was 286min (127-380min). The acrylonitrile butadiene styrene plastic models printed for the project proved to be optimal for the simulation of craniosynostosis surgeries, both anatomically and in terms of mechanical properties and reaction to surgical instruments.

CONCLUSIONS

3D printers have a wide range of medical applications and they offer an easy and affordable way to produce skull models. The acrylonitrile butadiene styrene material is suitable for the production of operable bone models as it faithfully reproduces the mechanical characteristics of bone tissue.

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.

Normative ranges of anthropometric cranial indices and metopic suture closure during infancy

OBJECTIVE Subjective evaluations typically guide craniosynostosis repair. This study provides normative values of anthropometric cranial indices that are clinically useful for the evaluation of multiple types of craniosynostosis and introduces 2 new indices that are useful in the evaluation and management of metopic and bicoronal synostosis. The authors hypothesize that normative values of the new indices as well as for established measures like the cephalic index can be drawn from the evaluation of CT scans of normal individuals. METHODS High-resolution 3D CT scans obtained in normal infants (age 0-24 months) were retrospectively reviewed. Calvarial measurements obtained from advanced imaging visualization software were used to compute cranial indices. Additionally, metopic sutures were evaluated for patency or closure. RESULTS A total of 312 participants were included in the study. Each monthly age group (total 24) included 12-18 patients, yielding 324 head CT scans studied. The mean cephalic index decreased from 0.85 at age 0-3 months to 0.81 at 19-24 months, the mean frontoparietal index decreased from 0.68 to 0.65, the metopic index from 0.59 to 0.55, and the towering index remained comparatively uniform at 0.64 and 0.65. Trends were statistically significant for all measured indices. There were no significant differences found in mean cranial indices between sexes in any age group. Metopic suture closure frequency for ages 3, 6, and 9 months were 38.5%, 69.2%, and 100.0%, respectively. CONCLUSIONS Radiographically acquired normative values for anthropometric cranial indices during infancy can be used as standards for guiding preoperative decision making, surgical correction, and postoperative helmeting in various forms of craniosynostosis. Metopic and towering indices represent new cranial indices that are potentially useful for the clinical evaluation of metopic and bicoronal synostoses, respectively. The present study additionally shows that metopic suture closure appears ubiquitous after 9 months of age.

The metopic index: an anthropometric index for the quantitative assessment of trigonocephaly from metopic synostosis

OBJECTIVE Because the metopic suture normally fuses during infancy, there are varying degrees of severity in head shape abnormalities associated with premature fusion. A method for the objective and reproducible assessment of metopic synostosis is needed to guide management, as current methods are limited by their reliance on aesthetic markers. The object of this study was to describe the metopic index (MI), a simple anthropometric cranial measurement. The measurements can be obtained from CT scans and, more importantly, from palpable cranial landmarks, and the index provides a rapid tool for evaluating patients in both pre- and postoperative settings. METHODS High-resolution head CT scans obtained in 69 patients (age range 0-24 months) diagnosed with metopic craniosynostosis were retrospectively reviewed. Preoperative 3D reconstructions were available in 15 cases, and these were compared with 3D reconstructions of 324 CT scans obtained in a control group of 316 infants (age range 0-24 months) who did not have any condition that might affect head size or shape and also in a subset of this group, comprising 112 patients precisely matched to the craniosynostosis patients with respect to age and sex. Postoperative scans were available and reviewed in 9 of the craniosynostosis patients at a mean time of 7.1 months after surgical repair. 3D reconstructions of these scans were matched with controls based upon age and sex. RESULTS The mean preoperative MI for patients with trigonocephaly was 0.48 (SD 0.05), significantly lower than the mean values of 0.57 (SD 0.04) calculated on the basis of all 324 scans obtained in controls (p < 0.001) and 0.58 (SD 0.04) for the subset of 112 age- and sex-matched controls (p < 0.001). For 7 patients with both pre- and postoperative CT scans available for evaluation, the mean postoperative MI was 0.55 (SD 0.03), significantly greater than their preoperative MIs (mean 0.48 [SD 0.04], p = 0.001) and comparable to the mean MI of the controls (p = 0.30). In 4 patients, clinically obtained postoperative MIs by caliper measurement were comparable to measurements derived from CT (p = 0.141). CONCLUSIONS The MI is a useful measurement of the severity of trigonocephaly in patients with metopic synostosis. This simple quantitative assessment can potentially be used in the clinical setting to guide preoperative evaluation, surgical repair, and postoperative degree of correction.

Normalization of brain morphology after surgery in sagittal craniosynostosis

OBJECT Nonsyndromic craniosynostosis (NSC) is associated with significant learning disability later in life. Surgical reconstruction is typically performed before 1 year of age to correct the cranial vault morphology and to allow for normalized brain growth with the goal of improving cognitive function. Yet, no studies have assessed to what extent normalized brain growth is actually achieved. Recent advances in MRI have allowed for automated methods of objectively assessing subtle and pronounced brain morphological differences. The authors used one such technique, deformation-based morphometry (DBM) Jacobian mapping, to determine how previously treated adolescents with sagittal NSC (sNSC) significantly differ in brain anatomy compared with healthy matched controls up to 11.5 years after surgery. METHODS Eight adolescent patients with sNSC, previously treated via whole-vault cranioplasty at a mean age of 7 months, and 8 age- and IQ-matched control subjects without craniosynostosis (mean age for both groups = 12.3 years), underwent functional 3-T MRI. Statistically significant group tissue-volume differences were assessed using DBM, a whole-brain technique that estimates morphological differences between 2 groups at each voxel (p < 0.01). Group-wise Jacobian volume maps were generated using a spacing of 1.5 mm and a resolution of 1.05 × 1.05 × 1.05 mm(3). RESULTS There were no significant areas of volume reduction or expansion in any brain areas in adolescents with sNSC compared with controls at a significance level of p < 0.01. At the more liberal threshold of p < 0.05, two areas of brain expansion extending anteroposteriorly in the right temporooccipital and left frontoparietal regions appeared in patients with sNSC compared with controls. CONCLUSIONS Compared with previous reports on untreated infants with sNSC, adolescents with sNSC in this cohort had few areas of brain dysmorphology many years after surgery. This result suggests that comprehensive cranioplasty performed at an early age offers substantial brain normalization by adolescence, but also that some effects of vault constriction may still persist after treatment. Specifically, few areas of expansion in frontoparietal and temporooccipital regions may persist. Overall, data from this small cohort support the primary goal of surgery in allowing for more normalized brain growth. Larger samples, and correlating degree of normalization with cognitive performance in NSC, are warranted.

Computer-assisted virtual planning and surgical template fabrication for frontoorbital advancement

OBJECT The authors describe a novel technique using computer-assisted design (CAD) and computed-assisted manufacturing (CAM) for the fabrication of individualized 3D printed surgical templates for frontoorbital advancement surgery. METHODS Two patients underwent frontoorbital advancement surgery for unilateral coronal synostosis. Virtual surgical planning (SurgiCase-CMF, version 5.0, Materialise) was done by virtual mirroring techniques and superposition of an age-matched normative 3D pediatric skull model. Based on these measurements, surgical templates were fabricated using a 3D printer. Bifrontal craniotomy and the osteotomies for the orbital bandeau were performed based on the sterilized 3D templates. The remodeling was then done placing the bone plates within the negative 3D templates and fixing them using absorbable poly-dl-lactic acid plates and screws. RESULTS Both patients exhibited a satisfying head shape postoperatively and at follow-up. No surgery-related complications occurred. The cutting and positioning of the 3D surgical templates proved to be very accurate and easy to use as well as reproducible and efficient. CONCLUSIONS Computer-assisted virtual planning and 3D template fabrication for frontoorbital advancement surgery leads to reconstructions based on standardizedmeasurements, precludes subjective remodeling, and seems to be overall safe and feasible. A larger series of patients with long-term follow-up is needed for further evaluation of this novel technique.

The suture provides a niche for mesenchymal stem cells of craniofacial bones

Bone tissue undergoes constant turnover supported by stem cells. Recent studies showed that perivascular mesenchymal stem cells (MSCs) contribute to the turnover of long bones. Craniofacial bones are flat bones derived from a different embryonic origin than the long bones. The identity and regulating niche for craniofacial-bone MSCs remain unknown. Here, we identify Gli1+ cells within the suture mesenchyme as the main MSC population for craniofacial bones. They are not associated with vasculature, give rise to all craniofacial bones in the adult and are activated during injury repair. Gli1+ cells are typical MSCs in vitro. Ablation of Gli1+ cells leads to craniosynostosis and arrest of skull growth, indicating that these cells are an indispensable stem cell population. Twist1(+/-) mice with craniosynostosis show reduced Gli1+ MSCs in sutures, suggesting that craniosynostosis may result from diminished suture stem cells. Our study indicates that craniofacial sutures provide a unique niche for MSCs for craniofacial bone homeostasis and repair.

The incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis following primary surgery

OBJECT Raised intracranial pressure (ICP) is recognized to occur in patients with nonsyndromic isolated sagittal craniosynostosis (SC) prior to surgery. However, the incidence of raised ICP following primary surgery is rarely reported and there appears to be a widely held assumption that corrective surgery for SC prevents the later development of intracranial hypertension. This study reports the incidence of postoperative raised ICP in a large cohort of patients with SC treated by 1 of 2 surgical procedures in a single craniofacial unit. METHODS A retrospective review was performed of all patients with SC who underwent either a modified strip craniectomy (MSC) or calvarial remodeling (CR) procedure under the care of the Oxford Craniofacial Unit between 1995 and 2010 and who were followed up for more than 2 years. The influence of patient age at surgery, year of surgery, sex, procedure type, and the presence of raised ICP preoperatively were analyzed. RESULTS Two hundred seventeen children had primary surgery for SC and were followed up for a mean of 86 months. The overall rate of raised ICP following surgery was 6.9%, occurring at a mean of 51 months after the primary surgical procedure. Raised ICP was significantly more common in those patients treated by MSC (13 of 89 patients, 14.6%) than CR (2 of 128 patients, 1.6%). Also, raised ICP was more common in patients under 1 year of age, the majority of whom were treated by MCS. No other factor was found to have a significant effect. CONCLUSIONS Postoperative raised ICP was found in more than 1 in 20 children treated for nonsyndromic SC in this series. It was significantly influenced by the primary surgical procedure and age at primary surgery. Careful long-term follow-up is essential if children who develop raised ICP following surgery are not to be overlooked.

The aesthetic outcome of surgical correction for sagittal synostosis can be reliably scored by a novel method of preoperative and postoperative visual assessment

BACKGROUND

Aims of surgical correction for isolated sagittal synostosis are functional and aesthetic. Multiple surgical techniques exist; however, reliable assessment of aesthetic outcome is poorly documented, limiting direct comparisons. The pinched appearance of the temporal regions is particularly challenging to correct. A visual analogue scale was designed to grade skull shape in patients who had total or subtotal calvarial remodeling for isolated sagittal synostosis.

METHODS

Twenty-two assessors graded preoperative and postoperative photographs from 42 consecutive cases of sagittal synostosis under a single surgeon. Five aspects were graded (i.e., narrow elongated skull, frontal bossing, temporal pinching, occipital bullet, and overall shape) from 0 (normal) to 100 (severe). Interobserver and intraobserver agreement were analyzed by calculating within-subject standard deviation, coefficient of variation, and intraclass correlation coefficient. Linear regression analysis determined predictors of outcome.

RESULTS

Surgery improved outcome dramatically across all five aspects of skull shape, with a 72.6 to 76.4 percent decrease in severity score. Improvements in severity score were greater after total calvarial remodeling, and type of calvarial remodeling (total versus subtotal) was an independent predictor of outcome in all aspects of skull shape (p≤0.001). Temporal pinching was improved in a subset of patients who also had onlay bone grafts in this region.

CONCLUSIONS

Calvarial remodeling is a powerful technique for improving skull shape. A panel can detect gross and subtle aesthetic changes after surgical correction of sagittal synostosis using a visual analogue scale, with moderate interobserver and intraobserver agreement. This provides a tool for future outcome assessment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The preoperative incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis is underestimated in the literature

OBJECT

The presence of raised intracranial pressure (ICP) in untreated nonsyndromic, isolated sagittal craniosynostosis (SC) is an important functional indication for surgery.

METHODS

A retrospective review was performed of all 284 patients presenting with SC to the Oxford Craniofacial Unit between 1995 and 2010.

RESULTS

Intraparenchymal ICP monitoring was performed in 39 children following a standard unit protocol. Monitoring of ICP was offered for all patients in whom nonoperative management was considered on the basis of minimal deformity or in cases in which parents were reluctant to agree to corrective surgery. These patients presented at an older age than the rest of the cohort (mean age 56 months), with marked scaphocephaly (16/39, 41%), mild scaphocephaly (11, 28%), or no scaphocephalic deformity (12, 31%). Raised ICP was found in 17 (44%) patients, with no significant difference in its incidence among the 3 different deformity types. Raised ICP was not predicted by the presence of symptoms of ICP or developmental delay or by ophthalmological or radiological findings.

CONCLUSIONS

The incidence of raised ICP in SC reported here is greater than that previously published in the literature. The lack of a reliable noninvasive method to identify individuals with elevated ICP in SC mandates consideration of intraparenchymal ICP monitoring in all patients for whom nonoperative management is contemplated.

Frame-based cranial reconstruction

The authors report on the first experiences with the prototype of a surgical tool for cranial remodeling. The device enables the surgeon to transfer statistical information, represented in a model, into the disfigured bone. The model is derived from a currently evolving databank of normal head shapes. Ultimately, the databank will provide a set of standard models covering the statistical range of normal head shapes, thus providing the required template for any standard remodeling procedure as well as customized models for intended overcorrection. To date, this technique has been used in the surgical treatment of 14 infants (age range 6-12 months) with craniosynostosis. In all 14 cases, the designated esthetic result, embodied by the selected model, has been achieved, without morbidity or mortality. Frame-based reconstruction provides the required tools to precisely realize the surgical reproduction of the model shape. It enables the establishment of a self-referring system, feeding back postoperative growth patterns, recorded by 3D follow-up, into the model design.

The shell technique: bilateral fronto-orbital reshaping in trigonocephaly

The shell technique, used in the Pediatric Neurosurgical Department at the Catholic University, Rome, since the 1990s for the correction of trigonocephaly, is associated to a significant reduction in surgical time and intraoperative blood loss as compared to other procedures, while allowing an adequate remodelling of the bifrontal bone by means of multiple radial osteotomies. The technique does not necessitate the creation of a supraorbital bar, as the supraorbital ridges are modified in situ, further reducing the operative blood loss. In spite of reduced surgical time and manipulation, this procedure ensures aesthetic and functional results comparable to more extensive and complex cranial vault reshaping procedures. The main limitation of this technique is related to the surgical timing, as better results are obtained between 3 and 9 months of age, when the skull bone is still ductile to work with, thus allowing it to be remodelled by greenstick fractures. Moreover, in this age group, the cranial defects that result from the enlargement of the frontal bone flap by means of radial cuts and from the anterior displacement of its lateral portions may benefit from the more effective bone regeneration which characterizes younger children as compared to their older counterparts. A small number of cases showing either persistent hypotelorism or temporal depression have been observed in the post-operative period, although these residual deformities probably depend on a more extensive involvement of the cranial base in the synostotic process in these patients than on the procedure itself.

A novel quantitative method for evaluating surgical outcomes in craniosynostosis: pilot analysis for metopic synostosis

Objective assessment of head shape has been an elusive goal in the management of craniosynostosis patients. Clinical judgment, craniometric indices, and computed tomography scans are the primary means through which a surgeon assesses this patient population. The purpose of this study was to examine and discuss the utility of the STARscanner for evaluation of surgical outcomes in metopic synostosis patients. A retrospective chart review of patients with metopic synostosis who underwent fronto-orbital advancement with pre- and postoperative STARscanner imaging at Texas Children's Hospital was performed. Two patients were identified and evaluation and discussion of the data produced by the STARscanner was undertaken. A novel symmetry index created by the authors, called the anterior-posterior volume ratio (APVR), was discussed for use in metopic synostosis patients. The postoperative growth metrics demonstrated an interval increase compared with the preoperative data. The anterior symmetry ratio, posterior symmetry ratio, overall symmetry ratio, cranial vault volumes, cranial vault asymmetry index, and cephalic ratio were not found to be useful in evaluating resolution of dysmorphology after fronto-orbital advancement in metopic synostosis. The APVR does not characterize dysmorphology, but may help show degree of expansion of the anterior cranial vault after fronto-orbital advancement. The STARscanner imaging device does not appear to have significant utility in characterizing head shape for surgical outcomes assessment in metopic synostosis. The minor utility of this device may be that it is a safe and fast way to derive growth parameters for both short-term and long-term follow-up of cranial vault remodeling.

Validation of cephalic index measurements in scaphocephaly

INTRODUCTION

The cephalic index (CI) of the head can be measured manually using a caliper, the original technique, but it is also possible to determine it using skull X-ray, 2DCT and 3DCT images, 3D photo and with help of plagiocephalometry (PCM).

PATIENTS AND METHODS

In this study, the manual caliper determination is statistically compared with other measuring methods for scaphocephaly patients (n = 39).

RESULTS

The CI mean differences for the most representative data are sequentially 3.74, 2.16, 1.09 and 0.97 for the 2DCT, PCM, 3D photo and 3DCT techniques. The CI 2DCT values show a significant difference (p < 0.01) in reference to CI manually, while the other techniques show a p > 0.05.

CONCLUSION

The conclusions are that significantly different results are achieved when using 2DCT relative to the manual caliper determination. No significant difference is observed between the 3D techniques and the manual method.

Isolated sagittal craniosynostosis: definition, classification, and surgical indications

Sagittal craniosynostosis (SC) remains the most common type of synostosis, accounting for about a half of all forms. It would result from a mesenchymal disorder involving the intramembranous ossification of the sagittal suture and leading to its early fusion. No specific data on the etiologic factors are currently available. The premature ossification of the sagittal suture can result in three main types of SC, according to the different segment prevalently involved: anterior, posterior, and complete SC. The diagnosis is easily obtained by clinical examination. However, a radiological work up (3D CT scan) may be necessary to rule out hidden venous or cranial anomalies possibly associated with most severe cases, or for the surgical planning. The most common indication for surgery is the improvement of the cosmetic appearance of the skull, since a cranial deformation may have a significant psychological impact on affected subjects. To relieve from raised intracranial pressure is a further indication to surgery. Although an increased intracranial pressure can be demonstrated in a minority of affected children at diagnosis, indeed, it can present later (usually after the second/third year of life) with chronic symptoms. The role of surgery in the preservation of cognitive functions in scaphocephalic patients does not seem to be relevant, since minor anomalies of the cerebral development associated with SC would occur independently from the cranial shape. On the other hand, the surgical correction may show a protective effect on some visual skills, like the ability to fix and follow, and the fixation shift.

Effect of molding helmet on head shape in nonsurgically treated sagittal craniosynostosis

OBJECT

Sagittal craniosynostosis is traditionally considered to be a surgical condition. Poor results of simple suturectomy follow from early reclosure of the suture. A wider craniectomy or use of interposing materials has not improved the outcome. However, endoscopic suturectomy supplemented with postoperative use of a molding helmet has shown good results. Because suturectomy reunites within 8-12 weeks of surgery, the authors questioned if the improved outcome was primarily related to use of the helmet.

METHODS

In 4 patients whose families opted for calvarial reconstruction when the infant was 4-6 months old, instead of endoscopic suturectomy, a molding helmet was used to minimize compensatory changes in the interim. Patients underwent 3D CT scanning to confirm craniosynostosis. Follow-up visits were made at intervals of 4 weeks for adjustment of the helmet, head circumference measurements, clinical photographs, and cranial index measurement.

RESULTS

There was significant improvement in the head shape within 6 weeks of use of the molding helmet. The cranial index score improved from a mean (± SD) of 67% ± 3% to 75% ± 2%.

CONCLUSIONS

These cases demonstrate that molding helmets improve head shape even without a suturectomy in patients with sagittal craniosynostosis, challenging the traditional view.