Impact of Fronto-Orbital Advancement on Frontal Sinus Volume, Morphology, and Disease in Nonsyndromic Craniosynostosis

Frontal Sinus Volume in Normocephalic Nonsyndromic Sagittal Craniosynostosis: A Comparative Study

PURPOSE

This study aimed to investigate frontal sinus volume as a potential indicator of cranial compensatory growth in unoperated normocephalic nonsyndromic sagittal craniosynostosis (NNSC) patients compared with age-matched and sex-matched controls. Previous studies have suggested that frontal sinus volume is suppressed in unoperated craniosynostosis and may be an intracranial space conservation phenomenon.

METHODS

Head computed tomographies (CTs) from 22 unoperated NNSC patients at our institution were utilized in this study and matched with age-matched and sex-matched control subjects. Frontal sinus volumes were measured using Syngo.Via, and statistical analysis was performed. Inclusion criteria for patients included the presence of a frontal sinus with unoperated sagittal craniosynostosis, whereas inclusion criteria for controls included the presence of a frontal sinus and no craniofacial trauma. Pearson correlation coefficient and significance values were calculated to evaluate the relationship between frontal sinus volume and craniosynostosis.

RESULTS

Six of 22 patients with NNSC were found to have the presence of a frontal sinus volume, compared with controls where all patients had the presence of a frontal sinus. When compared with age-sex matched controls, our analysis revealed a Pearson correlation coefficient of 0.993 and a high significance of P < 0.001, indicating a strong association between decreased-to-absent frontal sinus volume in unoperated NNSC patients.

CONCLUSION

The findings of this study demonstrate a correlation between decreased-to-absent frontal sinus volume in patients with NNSC in comparison to normal controls. These findings highlight the potential utility of frontal sinus volume as a diagnostic tool in identifying the degree of compensation that the skull has undergone in nonsyndromic sagittal craniosynostosis.

Frontal sinus hypoplasia in unoperated older patients with craniosynostosis: a pilot study

PURPOSE

The purpose of this study is to determine whether patients with unoperated craniosynostosis have different frontal sinus pneumatization than unaffected controls.

METHODS

Retrospective review was performed between 2009 and 2020 of previously unoperated patients with craniosynostosis older than 5 years old at first presentation to our institution. Total frontal sinus volume (FSV) was calculated using 3D volume rendering tool in Sectra IDS7 PACS system. Age-matched normative FSV data was collected from 100 normal CT scans for the control group. The two groups were statistically compared using Fisher's exact test and T-test.

RESULTS

Study group included nine patients, 5-39 years old, median age 7 years. Frontal sinus pneumatization was absent in 12% of the normal 7-year-old controls, while frontal sinus pneumatization was absent in 89% of the studied craniosynostosis patients (p < .001). Mean FSV of the study group (113 ± 340 mm3) was significantly different from that of age matched control mean FSV (2016 ± 2529 mm3) (p = .027).

CONCLUSIONS

Frontal sinus pneumatization is suppressed in unreleased craniosynostosis and may be an intracranial space conservation phenomenon. This absent frontal sinus can have implications in future frontal region trauma and frontal osteotomies.

The Effect of Fronto-Orbital Advancement on Frontal Sinus Development and Function in Non-Syndromic and Syndromic Craniosynostosis

The impact of fronto-orbital advancement (FOA) on frontal sinus development and function is anecdotally variable. The aim of this study was to assess the impact of FOA on development of frontal sinuses, and additionally to identify the complications that might arise out of such procedures. This was a retrospective case-control study. Non-syndromic and syndromic craniosynostosis patients (n = 58) who underwent FOA at an early age and also had a skull radiograph or CT scan after the age of 12 were selected. Age matched trauma patients with CT scans done beyond 12 years of age were used as controls. Age at first FOA surgery, total number of procedures and age at imaging was noted. Presence or absence of frontal sinuses was assessed using imaging studies initially. Patients with a formed frontal sinus and a CT scan were further chosen for volumetric studies. Complications related to frontal sinus and secondary surgeries were recorded. One of 27 non-syndromic patients had absent frontal sinuses. Seven of 31 syndromic patients had absent sinuses. Among 20 controls, only 1 patient did not develop frontal sinuses. The mean age at first FOA was 11.81 months and 18.25 months for non-syndromic and syndromic groups, respectively. The average number of procedures before 12 years of age was 1.25 and 1.51 for non-syndromic and syndromic patients, respectively. The mean age at imaging was 17.74, 20.96, and 20.25 years for non-syndromic, syndromic and control groups, respectively. The mean frontal sinus volumes were 13050.36, 15039.02, and 8459.48 mm for non-syndromic, syndromic and control groups, respectively. In conclusion, FOA does not seem to have an impact on rate of pneumatization in the background of similar rates in the non-syndromic and control groups. The low pneumatization rate in syndromic group might be a virtue of the disease itself. There were significant frontal sinus complications that occurred after fronto orbital advancement and this should be borne in mind during the surgical consenting process.

Syndromic Craniosynostosis

Management strategies for syndromic craniosynostosis patients require multidisciplinary subspecialty teams to provide optimal care for complex reconstructive approaches. The most common craniosynostosis syndromes include Apert (FGFR2), Crouzon (FGFR2), Muenke (FGFR3), Pfeiffer (FGFR1 and FGFR2), and Saethre-Chotzen (TWIST). Bicoronal craniosynostosis (turribrachycephaly) is most commonly associated with syndromic craniosynostosis. Disease presentation varies from mild sutural involvement to severe pansynostoses, with a spectrum of extracraniofacial dysmorphic manifestations. Understanding the multifaceted syndromic presentations while appreciating the panoply of variable presentations is central to delivering necessary individualized care. Cranial vault remodeling aims to relieve restriction of cranial development and elevated intracranial pressure and restore normal morphology.

Craniometric Analysis of Frontal Cranial Morphology Following Posterior Vault Distraction

BACKGROUND

Posterior vault distraction osteogenesis (PVDO) is believed to improve frontal contour in infants with syndromic craniosynostosis and turribrachycephaly. This study provides an objective craniometric analysis to determine how PVDO affects anterior cranial morphology.

METHODS

A retrospective chart review of patients who underwent PVDO was performed. Inclusion criteria included pre- and postoperative computed tomography (CT) scans within 3 months before surgery and another 1 to 6 months after device removal. Volumetric and craniometric data were derived using Mimics software and compared using paired t-test and Wilcoxon rank-sum test.

RESULTS

About 65 patients underwent PVDO, and 13 patients met inclusion criteria. Mean age at intervention was 3.4 ± 4.2 years. Total cranial volume increased 249 ± 159 cm in all patients (P = 0.0001) and 380 ± 128 cm in patients younger than 1 year of age (n = 6, P =0 .0008). Supraorbital retrusion decreased from 5.44 ± 3.89 to 4.54 ± 3.91 mm postoperatively (P = 0.0004), decreasing significantly in patients without previous frontal surgery and not in those with previous frontal surgery (P = 0.2115; comparison P = 0.0047). Basofrontal angle decreased by 2.92 ± 2.16 degrees (P = 0.0004) with a greater decrease of 3.33±2.68 degrees in those younger than 12 months (P = 0.0289) and 2.58±1.74 degrees in those older (P = 0.0079). No change was found in anterior cranial height and anterofrontal angle (P > 0.05).

CONCLUSION

PVDO improves frontal contour by decreasing supraorbital retrusion and reducing frontal bossing in syndromic craniosynostosis patients with turribrachycephaly. When combined with its demonstrated efficacy for cranial expansion, these frontal changes likely reinforce PVDO's ability to influence the timing of, and to a degree, the need for frontal surgery in this group.

Proof of Concept Study for the Design, Manufacturing, and Testing of a Patient-Specific Shape Memory Device for Treatment of Unicoronal Craniosynostosis

Treatment of unicoronal craniosynostosis is a surgically challenging problem, due to the involvement of coronal suture and cranial base, with complex asymmetries of the calvarium and orbit. Several techniques for correction have been described, including surgical bony remodeling, early strip craniotomy with orthotic helmet remodeling and distraction. Current distraction devices provide unidirectional forces and have had very limited success. Nitinol is a shape memory alloy that can be programmed to the shape of a patient-specific anatomy by means of thermal treatment.In this work, a methodology to produce a nitinol patient-specific distractor is presented: computer tomography images of a 16-month-old patient with unicoronal craniosynostosis were processed to create a 3-dimensional model of his skull and define the ideal shape postsurgery. A mesh was produced from a nitinol sheet, formed to the ideal skull shape and heat treated to be malleable at room temperature. The mesh was afterward deformed to be attached to a rapid prototyped plastic skull, replica of the patient initial anatomy. The mesh/skull construct was placed in hot water to activate the mesh shape memory property: the deformed plastic skull was computed tomography scanned for comparison of its shape with the initial anatomy and with the desired shape, showing that the nitinol mesh had been able to distract the plastic skull to a shape close to the desired one.The shape-memory properties of nitinol allow for the design and production of patient-specific devices able to deliver complex, preprogrammable shape changes.

Frontal Sinus Volume and Frontal Bar Position Are Associated in Unicoronal Craniosynostosis

BACKGROUND

Frontal sinus pneumatization plays an important role in brow protrusion, and absence of frontal sinus development may be associated with brow retrusion. Using unicoronal craniosynostosis as a model, the authors studied the relationship among frontal sinus volume, supraorbital retrusion, and brow position.

METHODS

The authors conducted a retrospective review of unicoronal craniosynostosis patients with head computed tomographic scans and photographs taken from ages 5 to 18 years. Frontal sinus volume and supraorbital retrusion were calculated using three-dimensional computed tomographic reconstructions. A "brow score" from 0 to 3 was assigned to each patient's photographs by a consensus of two craniofacial surgeons; sinus morphology and brow scores were compared.

RESULTS

The study included 20 unicoronal craniosynostosis patients. The affected side demonstrated increased retrusion (7.1 ± 3.7 mm versus 3.0 ± 3.1 mm; p < 0.001) and decreased frontal sinus volume (0.8 ± 0.9 cc versus 2.6 ± 1.8 cc; p < 0.001). Qualitative brow retrusion scores differed between affected and unaffected sides (score of 0, 17 percent affected versus 78 percent unaffected; score of 1, 28 percent versus 22 percent; score of 2, 39 percent versus 0 percent; and score of 3, 17 percent versus 0 percent; p < 0.001). Brow scores trended with retrusion measurements (score of 0, 2.7 ± 2.9 mm retrusion; score of 1, 6.1 ± 3.5 mm; score of 2, 8.9 ± 3.2 mm; and score of 3, 9.7 ± 2.8 mm; p < 0.001). Subjects with brow scores of 0 or 1 had larger frontal sinus volumes than subjects with brow scores of 2 or 3 (p = 0.018).

CONCLUSIONS

Qualitative brow retrusion correlates strongly with both quantitative supraorbital retrusion and frontal sinus volume. Although this retrospective study cannot prove causality, which is likely multifactorial, its strong correlation with frontal sinus pneumatization highlights the importance of the frontal sinus in brow position in unicoronal craniosynostosis.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.