Surgical correction of metopic synostosis

Machine learning applications in craniosynostosis diagnosis and treatment prediction: a systematic review

Craniosynostosis refers to the premature fusion of one or more of the fibrous cranial sutures connecting the bones of the skull. Machine learning (ML) is an emerging technology and its application to craniosynostosis detection and management is underexplored. This systematic review aims to evaluate the application of ML techniques in the diagnosis, severity assessment, and predictive modeling of craniosynostosis. A comprehensive search was conducted on the PubMed and Google Scholar databases using predefined keywords related to craniosynostosis and ML. Inclusion criteria encompassed peer-reviewed studies in English that investigated ML algorithms in craniosynostosis diagnosis, severity assessment, or treatment outcome prediction. Three independent reviewers screened the search results, performed full-text assessments, and extracted data from selected studies using a standardized form. Thirteen studies met the inclusion criteria and were included in the review. Of the thirteen papers examined on the application of ML to the identification and treatment of craniosynostosis, two papers were dedicated to sagittal craniosynostosis, five papers utilized several different types of craniosynostosis in the training and testing of their ML models, and six papers were dedicated to metopic craniosynostosis. ML models demonstrated high accuracy in identifying different types of craniosynostosis and objectively quantifying severity using innovative metrics such as metopic severity score and cranial morphology deviation. The findings highlight the significant strides made in utilizing ML techniques for craniosynostosis diagnosis, severity assessment, and predictive modeling. Predictive modeling of treatment outcomes following surgical interventions showed promising results, aiding in personalized treatment strategies. Despite methodological diversities among studies, the collective evidence underscores ML's transformative potential in revolutionizing craniosynostosis management.

Surgical strategy in treatment of metopic synostosis in a single centre experience: technical note and quantitative analysis of the outcomes

PURPOSE

Trigonocephaly is the most common craniosynostosis involving orbits. Although some degree of agreement has been reached regarding surgical timing and indications for treatment, there is no consensus regarding the ideal operative technique to guarantee an optimal morphological outcome. The purpose of this study is to describe both strategies and to compare morphological outcomes by means of morphological surface analysis obtained from three-dimensional (3D) stereophotogrammetry, with two different techniques.

METHODS

We retrospectively investigated 43 patients with metopic synostosis surgically treated between 2004 and 2020. Two different techniques were applied, addressed as technique A and B. Ten patients undergone postoperative 3d stereophotogrammetry were enrolled, and cephalometric measurements were taken and compared to a cohort of unaffected patients matched by age and gender.

RESULTS

Comparison of the groups demonstrated a hypercorrection of the metopic angle of the second technique, associated with a slightly lower correction of the interfrontoparietal diameter. The metopic angle showed to be significantly undercorrected with the first method.

CONCLUSIONS

Alternated barrel staving technique appears to be a quick and satisfactory method in cranial remodelling for metopic synostosis. It guarantees an optimal aesthetic result in the first years after surgery.

Experiences of surgical complications and reoperations in nonsyndromic sagittal synostosis patients in Oulu

OBJECTIVE

The purpose of this study was to evaluate the surgical complications of patients treated for nonsyndromic sagittal craniosynostosis and the necessity for reoperations due to craniocerebral disproportion.

MATERIALS AND METHODS

The patient cohort of this study consisted of patients (N = 82) who were treated in the Oulu University Hospital using the open vault cranioplasty with a modified H-technique between the years 2008 to 2022. There were 69 males (84.1%) and 13 females (15.9%). The mean age at the primary operation was 6.1 months. Mean follow-up time was 9.0 years.

RESULTS

There were no major complications related to the procedures. Two patients (2.4%) had a minor dural lesion. There were no postoperative wound infections. Of the 82 patients, seven patients with primary craniosynostosis (13.0%) developed symptomatic craniocerebral disproportion requiring reoperation to increase intracranial volume. In all these patients, invasive intracranial pressure (ICP) monitoring was performed prior to decision-making. In the majority of cases, the aesthetical outcome was considered good or excellent.

CONCLUSION

The operative method used was feasible and safe. Thirteen percent of patients who were followed over 5 years required major surgery due to development of craniocerebral disproportion later in life.

Validating the Supraorbital Notch-Nasion-Supraorbital Notch Angle as a Marker for Metopic Craniosynostosis Severity

OBJECTIVE

Metopic craniosynostosis (MCS) can be difficult to differentiate from metopic ridge (MR) or normal frontal morphology. This study assess whether the supraorbital notch-nasion-supraorbital notch (SNS) angle can help identify MCS.

METHODS

Records of 212 patients with preoperative three-dimensional computed tomography scans were examined. The SNS angles, surgeon craniofacial dysmorphology rankings, and CranioRate metopic severity scores (MSSs) were compared with the Spearman rank correlation coefficient. Receiver operating characteristic (ROC) curves with Youden J-statistic and cross-validation of regression models assessed the ability of these measures to predict surgery.

RESULTS

A total of 212 patients were included, consisting of 78 MCS, 37 MR, and 97 controls. Both the mean SNS angle (MCS: 111.7 ± 10.7 degrees, MR: 126.0 ± 8.2 degrees, controls: 130.7 ± 8.8 degrees P < 0.001) and MSS (MCS: 5.9 ± 2.0, MR: 1.4 ± 1.9, controls: 0.2 ± 1.9, P < 0.001) were different among the cohorts. The mean SNS angle (111.5 ± 10.7 versus 129.1 ± 8.8, P < 0.001) was lower in those who had surgery and CranioRate score (5.9 ± 2.1 versus 0.8 ± 2.2, P < 0.001) was higher in those who underwent surgery. SNS angles were positively correlated with surgeon craniofacial dysmorphology rankings ( r = 0.41, P < 0.05) and CranioRate MSS ( r = 0.54, P < 0.05). The ROC curve requiring high sensitivity revealed an SNS angle of 124.8 degrees predicted surgery with a sensitivity of 88.7% and a specificity of 71.3%. A ROC curve using the CranioRate MCC values ≥3.19 predicted surgery with 88.7% sensitivity and 94.7% specificity.

CONCLUSION

Orbital dysmorphology in patients with MCS is well captured by the supraorbital-nasion angle. Both the SNS angle and CranioRate MSS scores accurately predict surgical intervention.

A Suture-specific Photo Score for Metopic Synostosis

Head shape assessments in children with metopic synostosis are a relevant outcome measure in addition to functional measures, such as neurocognitive outcomes, behavioral outcomes, and visual functioning outcomes. However, consensus on head shape assessments in children with metopic synostosis is lacking. The aim of this study is to develop a reproducible and reliable suture-specific photo score that can be used for cross-center comparison of phenotypical severity of metopic synostosis and evaluation of esthetic outcome of treatment later in childhood. We conducted a retrospective study among nonsyndromic metopic synostosis patients aged <18 years. Preoperative and postoperative photosets of patients with metopic synostosis from 6 expert centers were included. The photo score was discussed in the group of expert craniofacial plastic surgeons and pediatric neurosurgeons. Interrater reliability was determined with modified weighted Fleiss' kappa and intraclass correlation coefficients. Correlation between individual photo score items with overall phenotype was assessed using Spearman correlation analyses. The metopic synostosis photo score contained the following items: "wedging of the forehead", "hypotelorism", "temporal hollowing", "biparietal widening,"and an assessment of "overall phenotype". Items were scored on a 4-point ordinal scale ranging from normal to severe. We found moderate interrater reliability for all items, but substantial agreement for the summed scores. Correlation with overall phenotype was lowest for biparietal widening. To conclude, although agreement on individual photo score items was suboptimal, the agreement on the summed score was substantial, which indicates there is consensus on the overall severity of the metopic synostosis phenotype.

Relating Metopic Craniosynostosis Severity to Intracranial Pressure

PURPOSE

A subset of patients with metopic craniosynostosis are noted to have elevated intracranial pressure (ICP). However, it is not known if the propensity for elevated ICP is influenced by the severity of metopic cranial dysmorphology.

METHODS

Children with nonsyndromic single-suture metopic synostosis were prospectively enrolled and underwent optical coherence tomography to measure optic nerve head morphology. Preoperative head computed tomography scans were assessed for endocranial bifrontal angle as well as scaled metopic synostosis severity score (MSS) and cranial morphology deviation score determined by CranioRate, an automated severity classifier.

RESULTS

Forty-seven subjects were enrolled between 2014 and 2019, at an average age of 8.5 months at preoperative computed tomography and 11.8 months at index procedure. Fourteen patients (29.7%) had elevated optical coherence tomography parameters suggestive of elevated ICP at the time of surgery. Ten patients (21.3%) had been diagnosed with developmental delay, eight of whom demonstrated elevated ICP. There were no significant associations between measures of metopic severity and ICP. Metopic synostosis severity score and endocranial bifrontal angle were inversely correlated, as expected (r=-0.545, P<0.001). A negative correlation was noted between MSS and formally diagnosed developmental delay (r=-0.387, P=0.008). Likewise, negative correlations between age at procedure and both MSS and cranial morphology deviation was observed (r=-0.573, P<0.001 and r=-0.312, P=0.025, respectively).

CONCLUSIONS

Increased metopic severity was not associated with elevated ICP at the time of surgery. Patients who underwent later surgical correction showed milder phenotypic dysmorphology with an increased incidence of developmental delay.

Neurocognitive outcomes of children with non-syndromic single-suture craniosynostosis

While the focus of craniosynostosis surgery is to improve head shape, neurocognitive sequelae are common and are incompletely understood. Neurodevelopmental problems that children with craniosynostosis face include cognitive and language impairments, motor delays or deficits, learning disabilities, executive dysfunction, and behavioral problems. Studies have shown that children with multiple suture craniosynostosis have more impairment than children with single-suture craniosynostosis. Children with isolated single-suture subtypes of craniosynostosis such as sagittal, metopic, and unicoronal craniosynostosis can have distinct neurocognitive profiles. In this review, we discuss the unique neurodevelopmental profiles of children with single-suture subtypes of craniosynostosis.

The Dura Split Technique in the Treatment of Craniosynostosis: Is It Still an Option?

BACKGROUND

The aim of this study was to report the outcome and the complications for patients operated on for craniosynostosis using the dura split technique. Specifically, the authors aimed to evaluate the safety of this technique, which is currently not in use, and to determine whether it is still useable.

METHODS

The data was collected from the hospital patient records of all children surgically treated for craniosynostosis using the dura split technique in Turku University Hospital during the period 1975 to 2015. The data was analyzed to determine the clinical and radiological outcomes of the surgical procedure, the need for reoperations, and the rate of complications.

RESULTS

During the study period, the dura split technique was used in the surgery of 65 patients. The outcome was either good or acceptable in most patients and reoperation was needed in only 2 patients (3.1%). Surgical complications included significant blood loss (26.2%), lesions on the inner layer of the dura (21.5%), leakage of cerebrospinal fluid (13.8%), and persistent bone defects (15.4% on palpation and 63.1% radiologically).

CONCLUSIONS

Although the outcome of surgery for craniosynostosis using the dura split technique was mostly acceptable and the need for reoperations rare, the technique cannot, however, be recommended in the future due to high rates of bone defects, frequent problems with lesions on the inner layer of the dura, and consequent perioperative leakage of cerebrospinal fluid.

Nonsyndromic craniosynostosis in Vietnam: initial surgical outcomes of subspecialty mentorship

OBJECTIVE

There is a global deficit of pediatric neurosurgical care, and the epidemiology and overall surgical care for craniosynostosis is not well characterized at the global level. This study serves to highlight the details and early surgical results of a neurosurgical educational partnership and subsequent local scale-up in craniosynostosis correction.

METHODS

A prospective case series was performed with inclusion of all patients undergoing correction of craniosynostosis by extensive cranial vault remodeling at Children's Hospital 2, Ho Chi Minh City, Vietnam, between January 1, 2015, and December 31, 2019.

RESULTS

A total of 76 patients were included in the study. The group was predominantly male, with a male-to-female ratio of 3.3:1. Sagittal synostosis was the most common diagnosis (50%, 38/76), followed by unilateral coronal (11.8%, 9/76), bicoronal (11.8%, 9/76), and metopic (7.9%, 6/76). The most common corrective technique was anterior cranial vault remodeling (30/76, 39.4%) followed by frontoorbital advancement (34.2%, 26/76). The overall mean operative time was 205.8 ± 38.6 minutes, and the estimated blood loss was 176 ± 89.4 mL. Eleven procedures were complicated by intraoperative durotomy (14.5%, 11/76) without any damage of dural venous sinuses or brain tissue. Postoperatively, 4 procedures were complicated by wound infection (5.3%, 4/76), all of which required operative wound debridement. There were no neurological complications or postoperative deaths. One patient required repeat reconstruction due to delayed intracranial hypertension. There was no loss to follow-up. All patients were followed at outpatient clinic, and the mean follow-up period was 32.3 ± 18.8 months postoperatively.

CONCLUSIONS

Surgical care for pediatric craniosynostosis can be taught and sustained in the setting of collegial educational partnerships with early capability for high surgical volume and safe outcomes. In the setting of the significant deficit in worldwide pediatric neurosurgical care, this study provides an example of the feasibility of such relationships in addressing this unmet need.

Part 1: Surgical Correction in 231 Trigonocephaly Patients - The Alder Hey Experience

ABSTRACT

Isolated metopic synostosis presents with a range of severity, from a palpable ridge as the sole presenting feature to a constellation of features resulting in trigonocephaly. At our unit, patients on the moderate to severe end of the phenotypic spectrum of trigonocephaly are offered fronto-orbital advancement and remodeling. The authors present our series of trigonocephaly patients who have undergone surgical correction. From January 2000 to January 2020, the authors operated on 231 patients with trigonocephaly. The average age at surgery was 18 months, with an average follow-up of 77.4 months. Seventy-nine percent of patients had no comorbidity. Ten percent of patients sustained a dural tear with no long-term consequences. The total early complication rate was 12.1%. The most common early complications were wound infection and wound dehiscence at 7.4% and 3.9% respectively. The total reoperation rate was 6.5%. The introduction of infection prevention and control measures over the 2 decades at our unit reduced the reoperation rate to 1.1%. The most common late complication was temporal recession in 20.8% of patients, none of whom required aesthetic correction. The recurrence rate of a metopic ridge was 2.3% with no patients requiring further surgery. None of our patients required calvarial remodeling for raised intracranial pressure after the primary fronto-orbital advancement and remodeling. There were no life-threatening complications or mortalities in our cohort. The authors present recommendations which include an infection control care bundle, cessation of surgical drains, and practice adjustments to reduce risks of infection and risk of requiring further calvarial remodelling for raised intracranial pressure.

Outcomes of Surgical Management of Metopic Synostosis : A Retrospective Study of 18 Cases

Objective

To describe the surgical management and postoperative outcomes in infants with metopic synostosis.

Methods

We conducted a 5 years retrospective chart review of patients who underwent surgical correction of metopic synostosis at two university hospitals in Egypt during the period between June 2014 and June 2019. The study is conducted to 18 children. The type of surgical procedures and postoperative outcomes were assessed in all patients.

Results

Five cases (27.8%) underwent endoscopic-assisted suturectomy, 10 cases (55.6%) underwent craniofacial reconstruction, and three cases (16.6%) underwent open burring of the metopic ridge. Fifteen patients underwent one surgery and three patients (16.6%) who need second operation. Ten patients (55.6%) had class I Whitaker classification.

Conclusion

Regardless of type of surgery, the outcomes of surgical correction of metopic synostosis are excellent with only a few patients require revision or develop major complications.

Quantifying Orthotic Correction of Trigonocephaly Using Optical Surface Scanning

ABSTRACT

Numerous publications describe techniques to measure trigonocephaly caused by metopic synostosis, but they are potentially hazardous for use in acquiring longitudinal data. Optical surface scanning technology can safely yield craniometrics but has not established a practical means for measuring objective morphological changes to trigonocephaly during the practical time constraints of a clinical visit. The purpose of this preliminary study was to evaluate a method for safely and repeatedly measuring frontal angle (FA) using technology available at multiple centers providing treatment with cranial remolding orthoses.Optical scans of infants who underwent endoscopic-assisted minimally-invasive craniectomy for repair of metopic synostosis with cranial remolding were retrospectively analyzed. A novel FA measurement technique "FA30" was developed based on repeatable, geometrically-related surface landmarks approximating the glabella and frontotemporali. Results were compared to a control group and categories of non-synostotic deformity. Inter-rater reliability was assessed for pre- and post-treatment scan measurements among separate clinicians.All trigonocephalic subjects (n = 5) had initial FA30 significantly lower than the control group and other cohorts (P < 0.001). During the course of orthotic cranial remolding following surgical release mean FA30 increased from 121.5° to 138.5° (P < 0.001), approaching the control group mean of 144.4°. Intraclass coefficient calculation showed high reliability (intraclass correlation coefficient: 0.993, 95% confidence interval: 0.957-0.998, P < 0.001), which was supported with Bland-Altman analyses of agreement.Optical surface scanning may provide a safe, accurate, and repeatable means to measure FA. Increase in FA30 demonstrates correction of trigonocephaly. The method presented enables expeditious reporting of treatment progress to the infant's surgeon and parents, and has potential for use in optimizing treatment outcomes at multiple centers.

Establishment of Objective Clinical Parameters for Assessment of Trigonocephaly: Are Caliper-Derived Clinical Measures Adequate?

OBJECTIVE

Objective clinical parameters characterizing the severity of trigonocephaly are essential given the concern for computerized tomography (CT) scans and radiation in infants. The present study seeks to develop a clinical tool by which to characterize trigonocephaly.

DESIGN

Retrospective cohort study.

SETTING

Tertiary academically affiliated children's medical center.

PARTICIPANTS

A retrospective review identified patients with trigonocephaly for whom surgery was recommended (group 1) and those with metopic ridging without significant trigonocephaly (group 2). Normal age-matched controls were also evaluated (group 3).

INTERVENTIONS

Cranial vault caliper measurements were compared across groups. Two ratios measuring anterior vault constriction were developed: (1) bitemporal width at the mid-forehead to the biparietal width, and (2) bitemporal width at the lateral brow to the biparietal width.

MAIN OUTCOME MEASURES

Bitemporal width to biparietal width (ratio).

RESULTS

Caliper measures were obtained from 19 patients in group 1, 8 patients in group 2, and 19 patients in group 3 (controls). Cranial indices were not significantly different across groups. The bitemporal width at the mid-forehead to the biparietal width ratio was significantly lower in group 1, with no difference between groups 2 and 3. The bitemporal width at the lateral brow to the biparietal width ratio was significantly different between all 3 groups, with group 1 < group 2 < group 3, respectively.

CONCLUSIONS

Bitemporal to biparietal ratios are a quantitative, objective clinical measure that can be used to differentiate patients with significant trigonocephaly from those with metopic ridging but no significant cranial deformity. These findings suggest that caliper-derived indices can assist in characterizing surgically relevant cranial vault deformities secondary to metopic synostosis and may circumvent CT-based analysis.

Three-Dimensional Analysis and Surgical Planning for Open Correction of Trigonocephaly

SUMMARY

Metopic craniosynostosis results in trigonocephaly, characterized by a triangular forehead with metopic ridge, bitemporal pinching, and narrow-set eyes with recessed lateral orbital rims. Surgical management is controversial but may include open expansion and vault remodeling, to enhance neurocognitive and aesthetic outcomes. This article and video vignette depict the diagnosis and treatment of metopic craniosynostosis, demonstrating the senior author's open approach, three-dimensional virtual surgical planning, and technical steps.

Photogrammetric evaluation of corrective surgery for trigonocephaly

The aim of this study was to capture preoperative, postoperative, and follow-up head shapes of male trigonocephaly patients who underwent fronto-orbital remodelling (FOR), using three-dimensional (3D) photography. Fifty-seven male infants with metopic synostosis operated on using standardized FOR during a 5-year period were included. All measurements were compared with those of an age-matched healthy control cohort (n = 253 for early postoperative comparison, n = 43 for the 1-year follow-up comparison) to determine the effect of FOR at 14 days and at 1 year post-surgery. Intracranial volume, frontal angle, nasofrontal angle, interfrontoparietal-interparietal ratio, and inter-orbital distances were measured 1 day preoperatively, 14 days and 1 year postoperatively. Mean age at surgery was 9.7 ± 1.1 months. Prior to surgery, boys with metopic synostosis showed a reduced intracranial volume (-7.0%, P < 0.001), frontal angle (-10.2%, P < 0.001), interfrontoparietal-interparietal ratio (-4.9%, P < 0.01), and orbital distances (-6.5%, P < 0.001) compared to the reference group, but values did not differ significantly from the specific control group after surgery (all P> 0.05). This was consistent by the time of the follow-up examination. Corrective surgery should therefore aim to achieve volume expansion and correction of the deformity. Furthermore, 3D photogrammetry provides a valuable alternative to computed tomography scans in the diagnosis of metopic synostosis, significantly reducing the amount of radiation exposure to the brain.

Craniometric Measurements and Surgical Outcomes in Trigonocephaly Patients Who Underwent Surgical Treatment

Objective

The aim of this study was to discuss the results of craniometric measurements and surgical treatments in patients operated for isolated trigonocephaly (TC) in light of the current literature.

Methods

A total of 18 cases who underwent surgery for isolated TC were included in the study. Age, gender, family history, follow-up time, complications, duration of surgery, surgical blood loss, and amount of blood replacement in these patients were recorded. Craniometric measurements such as metopic angle (MA), cephalic index (CI), interparietal distance (IPD), intercoronal distance (ICD), and their ratio to each other were evaluated according to pre-and postoperative parameters. Photographs of the patients were taken before and after the operation. The Whitaker classification and Kampf "aesthetic outcome staging" were used in the evaluations.

Results

The mean MA values after the operation increased to reach above 147 degrees in all cases. The average CI did not change. ICD measurement averages increased significantly. The average IPD/ICD ratio decreased due to the increase in ICD and the enlargement of the anterior fossa after the operation. According to the Whitaker classification and Kampf “aesthetic outcome staging” scale, 17 of our cases were at stage I, rated as perfect, and one was at stage II, rated as good.

Conclusion

Surgery performed at the appropriate time for TC yields cosmetically satisfactory results. Since potential neurological and cognitive morbidities occur mostly in school-age patients, long-term follow-up of the cases is required. Performing craniometric measurements enables patients to be evaluated with objective and measurable numerical data.

Craniofacial Sutural Pattern and Surgical Management in Patients With Different Degrees of Trigonocephaly Severity

The aim of this study was to identify quantitative tools to classify the severity of trigonocephaly to guide surgical management and predict outcome.

METHODS

We reviewed high-resolution computed tomography images of 59 patients with metopic synostosis. We assessed the craniofacial sutural pattern as well as interfrontal and metopic angles, and we related the frontal angulation degree with the sutural pattern, the surgical management, and clinical outcome.

RESULTS

We identified 3 groups according to the severity of trigonocephaly. No difference was found between the sutural pattern of nasion complex and severity, whereas the closure of zygomatic maxillary sutures increased with the severity degree (P < 0.05). The operative management was related to the severity degree (P < 0.001) and to the reduced age (P = 0.009).

CONCLUSIONS

Interfrontal and metopic angles are complementary measurements to evaluate with high accuracy the degree of frontal angulation. In preoperative assessment, they may guide surgery decision in particular when the choice is not straightforward.

Radiographic Severity of Metopic Craniosynostosis Correlates with Long-Term Neurocognitive Outcomes

BACKGROUND

Reports of neurodevelopmental delays in adolescents with metopic craniosynostosis have ranged from 15 to 61 percent. Previously, event-related potentials have correlated preoperative radiographic severity with language deficiencies in infancy. This study sought to characterize neurocognitive testing at cranial maturity and correlate outcomes to preoperative radiographic severity.

METHODS

Patients diagnosed with metopic craniosynostosis who underwent surgical correction in infancy completed a neurodevelopmental battery evaluating age-normalized intelligence quotient, academic achievement, and visuomotor integration. Data were stratified by preoperative endocranial bifrontal angle (moderate, >124 degrees; severe, <124 degrees). Multiple variable regression was used to control measured intelligence and achievement for age at surgery, age at testing, parental education, and income. Significance was set at p < 0.05.

RESULTS

Twenty patients completed neurodevelopmental testing. Mean intelligence quotient was 111.7 ± 13 and academic achievement was similar to national averages (word reading, 53.4 percent; reading comprehension, 53.4 percent; reading composite, 53.5 percent; spelling, 44 percent; and math, 52.9 percent). Radiographic measurements revealed 36 percent of patients with moderate phenotype and 64 percent with severe. Patients with severe phenotypes had lower intelligence quotient measures and scored more poorly in every academic measure tested. Word reading (113 versus 95; p = 0.035) and reading composite (109 versus 98; p = 0.014) reached significance.

CONCLUSIONS

Overall, cranial mature patients with metopic craniosynostosis had above average intelligence quotient and academic achievement near the national mean. Long-term neurocognitive function was correlated to preoperative radiographic severity in metopic craniosynostosis, with more severe cases performing worse.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

A review of the management of single-suture craniosynostosis, past, present, and future

BACKGROUND

Craniosynostosis is a condition in which 2 or more of the skull bones fuse prematurely. The spectrum of the disorder most commonly involves the closure of a single suture in the skull, but it can also involve syndromic diagnoses in which multiple skull bones and/or bones outside of the cranium are affected. Craniosynostosis can result in cosmetic deformity as well as potential limitations in brain growth and development, and the neurocognitive impact of the condition is just starting to be studied more thoroughly. Our knowledge regarding the genetics of this condition has also evolved substantially. In this review, the authors explore the medical and surgical advancements in understanding and treating this condition over the past century, with a focus on how the diagnosis and treatment have evolved.

METHODS

In this review article, the authors, who are the leaders of a craniofacial team at a major academic pediatric hospital, focus on single-suture craniosynostosis (SSC) affecting the 6 major cranial sutures and discuss the evolution of the treatment of SSC from its early history in modern medicine through the current state of the art and future trends. This discussion is based on the authors' broad experience and a comprehensive review of the literature.

SUMMARY

The management of SSC has evolved substantially over the past 100 years. There have been major advances in technology and medical knowledge that have allowed for safer treatment of this condition through the use of newer techniques and technologies in the fields of surgery, anesthesia, and critical care. The use of less invasive surgical techniques along with other innovations has led to improved outcomes in SSC patients. The future of SSC treatment will likely be guided by elucidation of the causes of neurocognitive delay in these children and assessment of how the timing and type of surgery can mitigate adverse outcomes.

Evaluation of Long-term Outcomes of Facial Sensation following Cranial Vault Reconstruction for Craniosynostosis

Supplemental Digital Content is available in the text.

Background:

Cranial vault reshaping to correct craniosynostosis in infants may injure terminal branches of the trigeminal nerve, namely the supraorbital, supratrochlear, zygomaticofacial, and zygomaticotemporal nerves, especially if a fronto-orbital advancement is performed. Despite numerous studies demonstrating successful esthetic outcome after FOA, there are no long-term studies assessing facial sensation after possible damage to these nerves as the result of surgery.

Methods:

A cross-sectional case-control research design was used to evaluate facial sensory threshold in the trigeminal branches after cranial vault reconstruction in children with isolated, nonsyndromic metopic, and unicoronal craniosynostosis, compared with those with sagittal craniosynostosis and age-matched nonaffected controls. Study participants were recruited from the Hospital for Sick Children between the ages of 6 and 18 years. Sensory outcome was determined using the Weinstein Enhanced Sensory Test, the Ten Test, and self-reported facial sensibility function questionnaire.

Results:

The sensory outcomes of 28 patients and 16 controls were examined at an average age of 9.6 years and 10.3 years, respectively. No subjective or objective sensory deficit was noted in supraorbital, supratrochlear, zygomaticofacial, or zygomaticotemporal nerve distributions between groups. Qualitative reports of facial sensibility function indicated no difference in subjective sensation, protective sensation, or motor behavior between groups.

Conclusions:

These results suggest that while sensory nerve injury during routine FOA may occur, it does not result in a quantifiable nor clinically significant long-term sensory deficit threshold. Patients do not develop long-term neuropathic pain following surgical intervention.

Endoscopy-assisted early correction of single-suture metopic craniosynostosis: a 19-year experience

In BriefThe long-term results of treating infants with metopic craniosynostosis by using endoscopic, minimally invasive techniques are reported. The impetus arose from the lack of consistent and favorable outcomes associated with calvarial vault remodeling techniques and from the very traumatic and invasive nature of these procedures. The results presented show excellent and consistent long-term outcomes that are superior to traditional methods and are associated with minimal trauma, blood loss, and anesthetic exposure, and with short surgical times.

Surgical Management and Evaluation of the Craniofacial Growth and Morphology in Cleidocranial Dysplasia

Cleidocranial dysplasia (CCD, MIM 119600) is a rare autosomal dominant disorder affecting bone, cartilage, craniofacial growth, and tooth formation leading to supernumerary teeth. Few reports delineate the genotype-phenotype correlations related to the variations in craniofacial morphology and patterning of the dentition and the complexity of treating patient's malocclusion. Successful management of the craniofacial deformities in patients with CCD requires a multidisciplinary team of healthcare specialists. Approximately 70% of patients are due to point mutations in RUNX2 and <20% due to copy number variations with the remainder unidentified. There is no literature to date, describing the orthognathic management of CCD patients with deletion in one of the RUNX2 alleles. The purpose of this study was to evaluate the craniofacial morphology and dental patterning in a 14-year-old Caucasian female with CCD resulting from a novel microdeletion of RUNX2 in 1 allele. The CCD patient with RUNX2 haploinsufficiency due to microdeletion had decreased craniofacial bone and ankyloses in the permanent dentition. An altered extraction protocol of supernumerary teeth was followed in this patient. Craniofacial growth and morphologic analysis demonstrated atypical skull shape, persistent metopic suture, and decreased mandibular size.

Personalized Optimal Planning for the Surgical Correction of Metopic Craniosynostosis

We introduce a quantitative and automated method for personalized cranial shape remodeling via fronto-orbital advancement surgery. This paper builds on an objective method for automatic quantification of malformations caused by metopic craniosynostosis in children and presents a framework for personalized interventional planning. First, skull malformations are objectively quantified using a statistical atlas of normal cranial shapes. Then, we propose a method based on poly-rigid image registration that takes into account both the clinical protocol for fronto-orbital advancement and the physical constraints in the skull to plan the creation of the optimal post-surgical shape. Our automated surgical planning technique aims to minimize cranial malformations. The method was used to calculate the optimal shape for 11 infants with age 3.8±3.0 month old presenting metopic craniosynostosis and cranial malformations. The post-surgical cranial shape provided for each patient presented a significant average malformation reduction of 49% in the frontal cranial bones, and achieved shapes whose malformations were within healthy ranges. To our knowledge, this is the first work that presents an automatic framework for an objective and personalized surgical planning for craniosynostosis treatment.

Neurodevelopmental Problems in Non-Syndromic Craniosynostosis

Craniosynostosis is the premature fusion of calvarial sutures, resulting in deformed craniofacial appearance. Hence, for a long time, it has been considered an aesthetic disorder. Fused sutures restrict growth adjacent to the suture, but compensatory skull growth occurs to accommodate the growing brain. The primary goal for the management of this craniofacial deformity has been to release the constricted skull and reform the distorted shape of the skull vault. However, the intellectual and behavioral prognosis of affected children has also been taken into consideration since the beginning of the modern era of surgical management of craniosynostosis. A growing body of literature indicates that extensive surgery, such as the whole-vault cranioplasty approach, would result in better outcomes. In addition, the age at treatment is becoming a major concern for optimal outcome in terms of cosmetic results as well as neurodevelopment. This review will discuss major concerns regarding neurodevelopmental issues and related factors.

Frontal cranial modeling using endocranial resorbable plate fixation in 27 consecutive plagiocephaly and trigonocephaly patients

INTRODUCTION

Premature ossification of coronal and metopic sutures is treated by fronto-orbital remodeling. Such operations require stable fixation of the reshaped cranial bones. Currently, biodegradable plating systems are used to provide sufficient stability over the time that takes for the osteotomies to ossify. Plates that are placed traditionally on the outer surface of the cranium are often palpable and even visible through the thin overlying skin, compromising the cosmetic results of these operations. Improved aesthetics could be achieved by placing the plates endocranially.

PURPOSE

This study aimed to evaluate endocranial resorbable plate fixation and its clinical and radiographic results in frontal remodeling cranioplasty for plagiocephaly and trigonocephaly patients with follow-up sufficiently long for the plates to have been completely resorbed.

METHODS

A poly(lactide-co-glycolide) (PLGA) resorbable plating system was used on the inner aspect of frontal bone in 27 patients treated for coronal and metopic craniosynostoses. The outcome was evaluated at follow-up visits. The mean follow-up was 79.2 months.

RESULTS

Three patients had complications that required reoperations. None of these complications were related to the endocranial location of the plates. There were no problems with ossification of the osteotomy sites. All but one patient's outcome was judged as good or excellent.

CONCLUSION

Placement of resorbable fixation on the endocranial surface of the calvarial bones is safe, stable, and results in satisfactory aesthetics without interfering with the ossification of the cranial bones.

Trigonocephaly: A simple modified technique

Trigonocephaly is the premature fusion of the metopic suture leading to deformation of anterior calvarium causing keel shaped deformity of forehead. In most cases, surgical correction is for aesthetic and psychosocial reasons. Various techniques have been described. Here we describe a technique, which is simple to perform with good postoperative results. Metopic suture is excised, one side is reconstructed in finger clasping manner to fit in an expanded area, and the other side is transected and simply molded, and all these fixed with nonabsorbable suture. Supraorbital horizontal bar is mobilized on either side anteriorly and fixed with titanium plate and screws.

Evidence-based medicine: Craniosynostosis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: (1) Make the appropriate diagnosis for each of the single-sutural synostoses, based on the physical examination. (2) Explain the functional concerns associated with these synostoses and why surgical correction is indicated. (3) Distinguish between the different types of surgical corrections available, the timing for these various interventions, and in what ways these treatments achieve overall management objectives. (4) Identify the basic goals involved in caring for the syndromic synostoses.

SUMMARY

This article provides an overview of the diagnosis and management of infants with craniosynostosis. This review also incorporates some of the treatment philosophies followed at The Craniofacial Center in Dallas, but is not intended to be an exhaustive treatise on the subject. It is designed to serve as a reference point for further in-depth study by review of the reference articles presented. This information base is then used for self-assessment and benchmarking in parts of the Maintenance of Certification process of the American Board of Plastic Surgery.

Neurodevelopmental and esthetic results in children after surgical correction of metopic suture synostosis: a single institutional experience

INTRODUCTION

Metopic suture synostosis leading to trigonocephaly is considered the second most frequent type of craniosynostosis. Besides esthetic results, we present 25 consecutive pediatric cases operated upon metopic suture synostosis with a focus on the child's motor, speech, and neurocognitive development.

METHODS

Twenty-five children (aged 6 to 33 months; median 9.2 months) with trigonocephaly were operated upon between 2002 and 2012 with fronto-orbital advancement including frontal bone cranioplasty and fronto-orbital bandeau remodeling. Neurodevelopmental deficits were evaluated by a standardized questionnaire including gross motor function, manual coordination, speech, and cognitive function performed by independent pediatric/developmental neurologists before surgery and at 6 and 12 months of time interval postoperatively.

RESULTS

Twenty-one (84 %) boys and four (16 %) girls were included in this study. Mean follow-up period was 33 ± 28 months. Outcome analysis for esthetic results showed a high degree of satisfaction by the parents and treating physicians in 23 cases (92 %). Preoperative evaluation revealed neurodevelopmental deficits in 10 children (40 %; six mild, four moderate degree). Twelve children (48 %) were proven to have a normal preoperative neuropediatric development. Mild or moderate developmental restraints were no longer apparent in 6/13, improved but still apparent in 3/13, and stable in 4/13, 6 months after cranial vault reconstruction. At 12 months of follow-up, deficits were no longer present in 9/13 and improved in 4/13. Apart from this cohort, two children were diagnosed with a syndromic form, and one child had a fetal valproate syndrome. In these three children, neurodevelopmental deficits were more pronounced. Neurocognitive progress was obvious, but was comparably slower, and major deficits were still apparent at last follow-up. All children with proven mild/moderate/severe deficits received intensive physiotherapy, logopedic, or neurobehavioral support.

CONCLUSIONS

As shown in a single-center observation, surgical correction of metopic suture synostosis not only refines esthetic appearance but also might improve neurodevelopmental outcome if deficits are apparent, even in syndromic forms of the deformity under additional physiotherapy, logopedic, or neurobehavioral support.

Assessing aesthetic outcomes after trigonocephaly correction

PURPOSE

This study analysed the aesthetic outcome assessments after trigonocephaly correction using different assessor groups.

METHODS

Twenty-four patients (9 males, 15 females) with a surgical age between 8 and 10 months were included. Standardised photographs showing different facial views of the patients between ages 3 and 6 years were evaluated in terms of aesthetics by three study groups: surgeons, medical students, and lay persons. Each photograph was scored as follows: 1 (normal), 2 (acceptable, no need for revision), or 3 (unacceptable, needs revision).

RESULTS

The mean surgical age was 9.1 ±0.4 months. Based on the en-face images, the mean scores assigned by the surgeon, student, and lay groups were 1.4 ±0.49, 1.25 ±0.44, and 1.13 ±0.34, respectively. Based on the patients' profiles, the mean scores assigned by the surgeon, student, and lay groups were 1.37 ±0.49, 1.16 ±0.37, and 1.09 ±0.29, respectively. The scores of the hemi-profile evaluation were 1.14 ±0.35, 1.07 ±0.26, and 1.09 ±0.31, respectively. The scores of the frontal region were 1.47 ±0.54, 1.33 ±0.49, and 1.39 ±0.49, respectively. Within the orbital area, the surgeon, student, and lay groups assigned mean scores of 1.53 ±0.56, 1.29 ±0.46, and 1.15 ±0.36, respectively. The midface analysis showed mean scores of 1.8 ±0.66, 1.63 ±0.52, and 1.46 ±0.5, respectively. In all areas, there were significant differences (P < 0.05) among the assessor groups.

CONCLUSION

The expectations regarding aesthetic outcome differ considerably between experts and non-experts. The need for correction did not concern the reshaped bone but rather the soft tissue epicanthal area.

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.

Developmental constraints on behavioural flexibility

We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.