Evolution of Bandeau Shape, Orbital Morphology, and Craniofacial Twist after Fronto-Orbital Advancement for Isolated Unilateral Coronal Synostosis: A Case-Control Study of 2-Year Outcomes

Postoperative Orbital Morphology Observations Following Fronto-Orbital Advancement and Cranial Vault Remodeling in Patients With Unilateral Coronal Synostosis

OBJECT

Observations of preoperative and postoperative orbital morphology following fronto-orbital advancement and cranial vault remodeling (FOA and CVR) in patients with unilateral coronal synostosis (UCS).

METHODS

This retrospective cohort included patients diagnosed with unilateral coronal synostosis and treated with fronto-orbital advancement and cranial vault remodeling at the Children's Hospital of Fudan University. The orbital height, orbital width, and orbital volume were obtained from head 3-dimensional computed tomography of preoperation and postoperation. The DICOM data of CT were then imported into mimics research version 21.0. The authors measured OH and OW according to the bony landmarks, then reset the parameters of the soft tissue window, and conducted a 3-dimensional reconstruction of the orbital soft tissue to get OV. The preoperative and postoperative measurements of the intact side were compared with the affected side, respectively. Statistical analysis was performed using SPSS version 25.0 (Ρ=0.05).

RESULTS

Twelve patients with UCS (5 male, 7 female) meeting criteria were included in the study. There were 4 patients with UCS on the left and 8 on the right. The average age at initial surgery was 19.50 months. Before the operation, the data of the intact side and the affected side were compared, respectively, and the difference was found to be significant in OH (Ρ=0.005) and OW (Ρ=0.005), while the OV (Ρ=0.106) was not statistically significant. After procedures of FOA and CVR, the data of the intact side and the affected side were compared, respectively, the significant difference was found in OV (Ρ=0.002), while not in OH (Ρ=0.060) or OW (Ρ=0.066).

CONCLUSION

After undergoing the operation of FOA and CVR, the OH and OW of the ipsilateral and contralateral sides of patients with UCS were basically symmetrical, while the volume of the affected orbit was still relatively smaller.

Optimal untwisting of the orbital bandeau in unicoronal craniosynostosis correction: A finite element analysis

BACKGROUND

Surgical correction of unicoronal craniosynostosis (UCS) is highly complex due to its asymmetric appearance. Although fronto-orbital advancement (FOA) is a versatile technique for craniosynostosis correction, harmonization of the orbital bandeau in UCS is difficult to predict. This study evaluates the biomechanics of the orbital bandeau using different patterns and varying characteristics of inner cortical bone layer osteotomies in a finite element (FE) analysis.

METHOD

An FE model was created using the computed tomography (CT) scan of a 6.5-month-old male infant with a right-sided UCS. The unaffected side of the orbital bandeau was virtually mirrored, and anatomical correction of the orbital bandeau was simulated. Different combinations of osteotomy patterns, numbers, depths, and widths were examined (n = 48) and compared to an uncut model.

RESULTS

Reaction forces and maximum stress values differed significantly (p < 0.01) among osteotomy patterns and between each osteotomy characteristic. Regardless of the osteotomy pattern, higher numbers of osteotomies significantly (p < 0.05) correlated with reductions in reaction force and maximum stress. An X-shaped configuration with three osteotomies deep and wide to the bone was biomechanically the most favorable model.

CONCLUSION

Inner cortical bone layer osteotomy might be an effective modification to the conventional FOA approach in terms of predictable shaping of the orbital bandeau.

Alterations in Sphenoid Anatomy in Craniosynostosis: Implications for Fronto-Orbital Advancement

OBJECTIVE

Fronto-orbital advancement involves removal of the fronto-orbital bandeau. Visualization of the saw blade is lost as it passes through the fronto-orbital-sphenoid junction (FOSJ), placing the temporal lobe at risk of injury. We aim to provide a 3D analysis of the space surrounding this osteotomy to differentiate various types of craniosynostoses.

DESIGN

Retrospective cohort.

SETTING

Institutional.

PATIENTS

Thirty patients with isolated unicoronal synostosis, nonsyndromic bicoronal synostosis, metopic synostosis, Apert syndrome, Crouzon syndrome, and Muenke syndrome.

INTERVENTIONS

CT scans conducted between 2 months to 2 years of age were 3D reconstructed to compare craniometrics against normal controls.

MAIN OUTCOME MEASURE(S)

Craniometrics.

RESULTS

The mean bone thickness of the FOSJ at the level of the supraorbital rim was significantly small for the Apert, unicoronal and bicoronal groups. The mean vertical height of the middle cranial fossa from the lesser sphenoid wing was significantly greater in the unicoronal group. The mean vertical height of the tip of the temporal lobe from the lateral sphenoid ridge was greater in the unicoronal, isolated bicoronal, and Apert groups. The mean corneal protrusion beyond the lateral orbital rim was significantly greater in the Apert and unicoronal groups. The mean horizontal depth of the orbit was smallest in the Apert group. The mean vertical distance between the dacryon and the foramen cecum, and the mean volume of temporal lobe beneath the sphenoid shelf were the largest in the Apert group.

CONCLUSIONS

Patients with Apert syndrome have the most unfavorable morphology of the anterior and middle cranial fossae.

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

OBJECTIVE

To systematically review the published comparative aesthetic outcomes, and its determinants, for craniosynostoses surgically treated by minimally-invasive cranial procedures and open cranial vault remodeling (CVR).

DESIGN

PRISMA-compliant systematic review.

SETTING

Not-applicable.

PATIENTS/PARTICIPANTS

Articles were included if they compared spring cranioplasty, strip minimally-invasive craniectomy or CVR for outcomes related to aesthetics or head shape. Forty-two studies were included, comprising 2402 patients.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

The craniometric and PROM used to determine surgical outcomes.

RESULTS

Twenty-five studies (59%) evaluated sagittal craniosynostosis, with metopic (7;17%) and unicoronal (4;10%) the next most prevalent. Thirty-eight studies (90%) included CVR, 24 (57%) included strip craniectomy with helmeting, 9 (22%) included strip craniectomy without helmeting, 11 (26%) included spring cranioplasty, and 3 (7%) included vault distraction. A majority of studies only used 1 (43%) or 2 (14%) craniometric measures to compare techniques. In sagittal synostosis, 13 (59%) studies showed no difference in craniometric outcomes, 5 (23%) showed better results with CVR, 3 (14%) with strip craniectomy, and 1 (5%) with springs. In studies describing other synostoses, 10/14 (71%) were equivocal. Subjective outcome measures followed similar trends. Meta-analysis shows no significant difference in cranial index (CI) outcomes between CVR and less invasive procedures in patients with sagittal synostosis.

CONCLUSIONS

There is no difference in CI outcomes between CVR and less invasive procedures. The majority of literature comparing craniometric and aesthetic outcomes between CVR and less invasive procedures shows equivocal results for sagittal synostosis. However, the heterogeneity of data for other craniosynostoses did not allow meta-analysis.

A Three-Dimensional-Based Morphometric Analysis of a Standardized Overcorrection Technique for Fronto-Orbital Advancement in Metopic Craniosynostosis

INTRODUCTION

The concept of "overcorrection" for trigonocephaly has been reported to achieve both anterior cranial fossa expansion and normalization of craniofacial form. The purpose of this study is to describe in detail a standardized technique to fronto-orbital advancement utilizing the concept of "overcorrection" and objectively evaluate intermediate results.

METHODS

This retrospective study included patients with isolated metopic synostosis who underwent surgery via the proposed surgical technique and age and sex-matched unaffected controls. Craniofacial morphometric analysis was performed on pre-, immediate post-, and intermediate postoperative (>2 years) three-dimensional (3D)-rendered computed tomographic (CT) scans and photographs. Key CT-based measurements included interzygomaticofrontal suture distance (IZFS), endocranial bifrontal angle (ECA), and temporal expansion. 3D photogrammetry was performed using established measurements and associated Z-scores converted. A Paired t-test and analysis of variance were performed when appropriate.

RESULTS

Forty-one patients were included. A comparison of pre- and immediate postoperative CT scans demonstrated statistically significant increases in all measurements. Subset analysis of 12 patients with intermediate follow-up (age: 39.6 ± 3.6 months) demonstrated significant differences from preoperative values except for IZFS, which decreased from immediate postoperative values and was smaller than age- and sex-matched controls. 3D photogrammetry demonstrated a mean Z-score above the norm for frontal breath. 3D photogrammetry is also positively correlated with CT-based measurements.

CONCLUSIONS

This standardized "overcorrection" approach for trigonocephaly can provide the appropriate changes to maintain a normal ECA despite a reduction in bifrontal width over time. 3D photogrammetry positively correlated with CT-based measurements and may provide useful information when following patients clinically. Long-term follow-up assessment to determine the necessary degree of overcorrection at skeletal mature is needed.

Patient-Specific Implants and Fat Grafting for Contour Deformities Post Craniosynostosis Reconstruction: A Therapeutic Approach

BACKGROUND

Contour deformities after fronto-orbital advancement for craniosynostosis reconstruction are commonly encountered. There is a paucity of literature describing secondary procedures to correct such deformities with reported outcomes. An approach to defect analysis and procedure selection is lacking. The authors present our experience utilizing fat grafting (FG) and patient-specific implant (PSI) reconstruction as management strategies for this population.

METHODS

A retrospective analysis of consecutive patients who underwent secondary onlay PSI or FG for contour deformities after primary craniosynostosis reconstruction was carried out. Patient demographics, defect analysis, surgical approach, postoperative complications, and esthetic outcomes were recorded. Data were pooled across the entire cohort and presented in a descriptive manner.

RESULTS

Fourteen patients (36% syndromic and 64% isolated) were identified that either underwent PSI (n = 7) with a mean follow-up of 56.3 weeks, FG (n = 5) with a mean follow-up of 36 weeks or a combination of both (n = 2) for deformities postcraniosynostis surgery. Supraorbital retrusion and bitemporal hollowing were the most common deformities. There were no intraoperative or postoperative complications. All patients achieved Whitaker class I esthetic outcomes and there were no additional revisions during the defined study period. The presence of a significant structural component or large (>5 mm) depression typically necessitated a PSI.

CONCLUSIONS

Contour deformities after fronto-orbital advancement reconstruction can be successfully managed using FG and PSI either as a combination procedure or in isolation. The authors have proposed anatomical criteria based on our experience to help guide procedure selection. Future prospective studies would be beneficial in providing more objective assessment criteria.

One-piece fronto-orbital distraction osteogenesis without bandeau in patients with coronal craniosynostosis: A five-year follow-up retrospective study of 45 consecutive patients

This study aimed to review the surgical outcomes, complications, and long-term relapses in patients with unilateral or bilateral coronal craniosynostosis, who underwent one-piece fronto-orbital distraction osteogenesis (FODO) without bandeau. The cephalic index, frontal angle, and supraorbital symmetry ratio were measured on the initial and follow-up computed tomography images. Esthetic outcomes were evaluated using the Whitaker classification. 45 patients were included in this study. The average follow-up interval was 5.4 ± 1.1 years (range 2.5-8.5 years). In patients with bilateral coronal craniosynostosis, the frontal angle decreased with a relapse ratio of -2.8 ± 4.3% during long-term follow-up compared with that during short-term follow-up (p = 0.028). In patients with unilateral coronal craniosynostosis, the supraorbital symmetry ratio decreased slightly, with a relapse ratio of -3.8 ± 2.6% during long-term follow-up (p = 0.017). Complications included dural tears during osteotomy (n = 2), early distractor removal (n = 2), and wound problems (n = 3). Within the limitations of the study it seems that one-piece fronto-orbital distraction osteogenesis (FODO) generates successful and sustainable results even in the long term. Therefore, this treatment option should be considered for patients with unilateral and bilateral coronal craniosynostoses whenever appropriate.

Fronto-Orbital Advancement for Metopic and Unilateral Coronal Craniosynostoses

Fronto-orbital advancement remains a powerful technique for the correction of anterior cranial vault differences related to metopic (trigonocephaly) or unilateral coronal (anterior plagiocephaly) craniosynostoses. Traditional fronto-orbital advancement requires access to the forehead and superior 2/3 of the orbit via a coronal incision. The frontal bone and orbital segment (bandeau) are then separated from the skull and reshaped. In patients with metopic craniosynostosis, the bandeau and frontal bone will need to be advanced and widened. In patients with unilateral coronal craniosynostosis, the bandeau will need to be "untwisted" to address the supraorbital retrusion on the affected side, the affected orbit will need to be shortened and widened, and the frontal bone flap will need to be proportionately advanced on the affected side. Overcorrection of the affected dimension should be undertaken to account for growth and relapse.

Treatment of Unicoronal Craniosynostosis by Rotational Flap Technique Preserves Blood Supply to the Frontal Bone Flap

BACKGROUND

Surgical correction of unicoronal craniosynostosis (UCS) remains a challenging problem. Long-term results are often unsatisfactory secondary to recurrence of the original deformity, requiring secondary operations such as fat grafting or complete revision of the calvarial remodeling. Distraction osteogenesis (DO) has recently emerged as a new modality for treatment of UCS, with promising results and decreased rates of reoperation compared with open cranial vault remodeling. A theoretical benefit of DO is preservation of blood supply to the frontal bone following osteotomy, as the frontal bone can be retained in situ compared with the complete removal and reshaping of the frontal bone during traditional fronto-orbital advancement. Preservation of blood supply to the frontal bone may allow for more robust bony healing and preservation of long-term growth potential; however, the vascularity of the frontal bone flap in DO has not previously been demonstrated. Here, we demonstrate unequivocally that blood supply to the frontal bone is preserved after creation of a rotational bone flap in DO management of UCS.

METHODS

Frontal bone flap creation via osteotomy for DO treatment of UCS was performed via previously reported technique. Indocyanine green was injected intravenously, and bone perfusion was assessed with a fluorescence imaging system.

RESULTS

Four patients underwent three cranial remodeling and three distractor removal procedures. After frontal bone flap creation via osteotomy for DO, perfusion to the osteotomized portion of the frontal bone flap is preserved. Blood flow is seen crossing the midline of the frontal bone. After removal of the distractor, perfusion in the osteoid consolidate is also observed.

CONCLUSIONS

Preservation of blood supply has not been previously demonstrated empirically in the setting of DO treatment of UCS. We show for the first time that during frontal bone flap creation, blood flow to the osteotomized portion of the frontal bone flap is maintained. Robust blood flow to the osteoid consolidate is also demonstrated. These data support the use of DO in treatment of UCS, as preserved blood supply to the bone is more likely to support improved healing and long-term results.

Virtual Coordinate System in Unicoronal Synostosis

We propose a landmark-based, virtual coordinate system, specifically designed for assessment of asymmetrical craniofacial anatomy associated with unicoronal synostosis.

Method

CT scans of 33 patients with nonsyndromic unicoronal synostosis were included. Proposed mid-sagittal plane was compared with commonly used sagittal planes: (1) nasion, sella, and basion (N-S-BA); (2) midplane of bilateral frontozygomatic sutures (midFZ); and (3) the skull gravity center plane, to evaluate reliability and validity in the assessments of the anterior and posterior skull base.

Results

The proposed midplane is similar to the midFZ plane in describing the direction of the anterior skull base. However, it has less bias than the N-S-BA (P < 0.001), and the gravity center planes (P < 0.001). The proposed midplane measures the direction of the posterior skull base plane, similar to the midFZ and gravity center planes, but it has less measurement deviation than the N-S-BA plane (P < 0.001). The most protrusive point on the frontal bone in unicoronal patients is contralateral to the fused suture and distant from the mid-sagittal plane by 13.93 ± 4.01 mm. In addition, it is more anteriorly positioned, by 5.32 mm (P < 0.001), when compared with the corresponding point on the synostotic side. The uppermost point of the supraorbital rim on the synostotic side is cephalic to that of the contralateral side by 4.09 mm (P < 0.001).

Conclusions

Prioritized orientation of an averaged Frankfort horizontal plane, followed by the location of the mid-sagittal and coronal planes, can generate a reliable and valid coordinate framework for the assessment of asymmetric skull shape in unicoronal synostosis.

Evolution of Cranioorbital Shape in Nonsyndromic, Muenke, and Saethre-Chotzen Bilateral Coronal Synostosis: A Case-Control Study of 2-Year Outcomes

BACKGROUND

The purpose of this study was to quantify change in cranioorbital morphology from presentation, after fronto-orbital advancement, and at 2-year follow-up.

METHODS

Volumetric, linear, and angular analyses were performed on computed tomographic scans of consecutive bilateral coronal synostosis patients. Comparisons were made across three time points, between syndromic and nonsyndromic cases, and against normal controls. Significance was set at p < 0.05.

RESULTS

Twenty-five patients were included: 11 were nonsyndromic, eight had Saethre-Chotzen syndrome, and six had Muenke syndrome. Total cranial volume was comparable to normal, age-matched control subjects before and 2 years after surgery despite an expansion during surgery. Axial and sagittal vector analyses showed advancement and widening of the lower forehead beyond control values with surgery and comparable anterior position, but increased width compared to controls at 2 years. Frontal bossing decreased with a drop in anterior cranial height and advanced lower forehead position. Middle vault height was not normalized and turricephaly persisted at follow-up. Posterior fossa volume remained lower at all three time points compared to control subjects. Supraorbital retrusion relative to anterior corneal position was overcorrected by surgery, with values comparable to those of control subjects at 2 years because of differential growth. There was no difference at 2 years between syndromic and nonsyndromic groups.

CONCLUSIONS

Open fronto-orbital advancement successfully remodels the anterior forehead but requires overcorrection to be comparable to normal at 2 years. Although there are differences in syndromic cases at presentation, they do not result in significant morphometric differences on follow-up. Posterior fossa volume remains lower at all time points.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Pediatric Fronto-Orbital Skull Reconstruction

Craniofacial surgery in children is a highly challenging discipline that requires extensive knowledge of craniofacial anatomy and pathology. Insults to the fronto-orbital skeleton have the potential to inflict significant morbidity and even mortality in patients due to its proximity to the central nervous system. In addition, significant aesthetic and ophthalmologic disturbances frequently accompany these insults. Craniosynostosis, facial trauma, and craniofacial tumors are all pathologies that frequently affect the fronto-orbital region of the craniofacial skeleton in children. While the mechanisms of these pathologies vary greatly, the underlying principles of reconstruction remain the same. Despite the limited data in certain areas of fronto-orbital reconstruction in children, significant innovations have greatly improved its safety and efficacy. It is imperative that further investigations of fronto-orbital reconstruction are undertaken so that craniofacial surgeons may provide optimal care for these patients.

Technical Strategy Using Piezosurgery to Correct Flattened Supraorbital Rim in Unilateral Coronal Craniosynostosis

ABSTRACT

The surgical correction of orbital deformities in patients with unilateral coronal craniosynostosis is challenging. Traditional techniques have shown the persistence of orbital flattening. This study presents a new strategy for remodeling the compromised orbit, using the piezosurgery technique, which improves the orbital curvature.

Test-retest validation of a cranial deformity index in unilateral coronal craniosynostosis

Unilateral coronal craniosynostosis (UCS) affects many infants resulting in abnormalities affecting the forehead and orbits. As a result, the deformity caused by UCS is very noticeable and there are several surgical treatment options available to normalize the head shape. However, there is a lack of consistently used outcome measures, resulting in difficulty assessing surgical outcomes and on-going debate over optimal treatments. Current techniques to quantify deformity in UCS are cumbersome, provide limited information, or are based on subjective assessments. In this study, a cranial deformity index was developed to quantify abnormality at the frontal bones for UCS that is accessible, user-friendly, and generates objective surface distance measurements. The cranial deformity index is defined as the Euclidean distance at the point of the largest deviation between the deformed skull compared to a reference skull. In addition, the index was successfully used to quantify post-operative changes in a single case of UCS that underwent corrective surgery. The reproducibility of the index was assessed using test-retest reliability and was demonstrated to be highly reproducible (ICC = 0.93). A user-friendly measurement index that is based on open-source software may be a valuable tool for surgical teams. In addition, this information can augment the consultation experience for patients and their families.