Use of computer-assisted design and manufacturing to localize dural venous sinuses during reconstructive surgery for craniosynostosis

The Role of Virtual Surgical Planning in Surgery for Complex Craniosynostosis

Background

Virtual surgical planning (VSP) decreases reliance on intraoperative subjective assessment of aesthetic and functional outcomes in craniofacial surgery. Here, we describe our experience of using VSP for complex craniosynostosis surgery to inform preoperative decision making and optimize postoperative outcomes.

Methods

Chart review was performed for children treated with craniosynostosis at our institution from 2015 to 2021. Eight VSP maneuvers were defined and assigned to each patient when applicable: (1) complex cranioplasty: combined autologous and synthetic; (2) autologous cranioplasty; (3) synthetic cranioplasty; (4) vector analysis and distractor placement; (5) complex osteotomies; (6) multilayered intraoperative plans; (7) volume analysis; and (8) communication with parents. Outcomes between VSP and non-VSP cohorts were compared.

Results

Of 166 total cases, 32 were considered complex, defined by multisutural craniosynostosis, syndromic craniosynostosis, or revision status. Of these complex cases, 20 underwent VSP and 12 did not. There was no difference in mean operative time between the VSP and non-VSP groups (541 versus 532 min, P = 0.82) or in unexpected return to operating room (10.5% versus 8.3%, P = 0.84). VSP was most often used to communicate the surgical plan with parents (90%) and plan complex osteotomies (85%).

Conclusions

In this cohort, VSP was most often used to communicate the surgical plan with families and plan complex osteotomies. Our results indicate that VSP may improve intraoperative efficiency and safety for complex craniosynostosis surgery. This tool can be considered a useful adjunct to plan and guide intraoperative decisions in complex cases, reducing variability and guiding parental expectations.

Traditional Versus Virtual Surgery Planning of the Fronto-Orbital Unit in Anterior Cranial Vault Remodeling Surgery

BACKGROUND

Craniosynostosis correction surgery is a complex procedure, which involves complete dismantling and reassembly of the cranial vault components. The traditional planning method for these surgeries results in increased intra-operative time owing to its highly subjective nature. The advent of virtual surgical planning (VSP) platform has lead to a greater pre-operative insight and precision outcome in calvarial remodeling surgeries. The purpose of this paper is to evaluate intra-operative time and blood loss difference as a measure of surgical efficiency between VSP based template guided Anterior Cranial Vault Reconstruction (ACVR) with Fronto-Orbital Unit Advancement (FOUA) and the traditional surgeries.

METHODS

Data were collected from patients who underwent ACVR with FOUA in our unit. Patients were divided into 2 groups, Template Fronto-Orbital Unit (TFOU) group and Non-template Fronto-Orbital Unit (NFOU) group. In TFOU group, Virtual planning along with fabrication of Template guide was carried out. Patients undergoing ACVR using traditional techniques were categorized as NFOU group. A comparative prospective analysis was carried out in terms of Intra-operative time duration and blood loss. Student 't' test was used to compare the means of the 2 groups.

RESULTS

A total of 10 patients were included in the present study. There were 5 control (NFOU) and 5 TFOU cases. There was a significant decrease in the operating time in TFOU group compared to the NFOU group. TFOU group also showed reduced intra-operative bleed compared to the NFOU group.

CONCLUSION

Virtual surgical planning (VSP) and 3D modeling with prefabricated template guide augurs reliable outcomes and portends the possibility of lesser intra-operative time. It is a valuable tool, which offers enormous benefits in terms of precise pre-surgical planning with predictive results.

Total Cranial Reconstruction for the Treatment of Sagittal Craniosynostosis in Children

OBJECTIVE

To study the effect of total cranial reconstruction for sagittal synostosis (scaphocephaly) deformity in Chinese children.

METHODS

A retrospective analysis was performed involving 23 children with isolated non-syndromic sagittal synostosis who were treated by total calvarial vault remodeling after 1 year of age from May 2015 to June 2019 in the Department of Neurosurgery, Children's Hospital of Nanjing Medical University. The authors reconstruct patients' pre- and post-operative cranial thin-section CT scan images and those of the control group. The cephalic index (traditional, normative), intracranial volume, horizontal point of maximum width (H-PMW), vertical point of maximum width (V-PMW), frontal to head height ratio and occipital to head height ratio data were analyzed using a paired t test or Wilcoxon signed-rank test.

RESULTS

Twenty-three patients met the inclusion criteria, including 19 males and 4 females. The ratio of males to females was 4.7:1. All patients underwent total cranial reconstruction. The average age was 26.52 months (13-48 months), the average operation time was 214.13 minutes (150-265 minutes), and the average amount of suspended erythrocytes was 200 ml (100-400 ml). The cranial morphology of all patients improved significantly after the operation. The traditional cephalic index (pre-operative: 0.70 (0.04); post-operative: 0.78 (0.02)) and normative cephalic index (pre-operative: 0.68 (0.03); post-operative: 0.77 (0.02)) were significantly increased (P < 0.0001). The mean horizontal point of maximum width improved from 0.54 to 0.56 (P = 0.0043), the mean vertical point of maximum width decreased from 0.59 to 0.54 (P = 0.0006), the frontal height decreased from 0.89 to 0.77 (P < 0.0001), and the occipital height improved from 0.78 to 0.88 (P < 0.0001). The intracranial volume increased from 1287.35 to 1426.90 cm3 (P < 0.0001). All of the children had a good skull shape and no recurrence of deformity.

CONCLUSIONS

Total calvarial reconstruction can effectively correct scaphocephaly in Chinese children, expand cranial volume, reduce cranial height, shorten fronto-occipital diameters and enlarge biparietal diameters.

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.

An Overview of Modelling Craniosynostosis Using the Finite Element Method

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

How does nonsyndromic craniosynostosis affect on bone width of nasal cavity in children? - Computed tomography study

Craniosynostosis is caused by premature fusion of one or more cranial sutures, restricting skull, brain and face growth. Nonsyndromic craniosynostosis could disturb the proportions of face. Although morphometric diameters of nasal cavity in healthy children are already known, they have not been established yet in children with nonsyndromic craniosynostosis. The aim our study was to check whether diameters of bone structures of nasal cavity in children with nonsyndromic craniosynostosis measured in CT are within normal range. 249 children aged 0–36 months (96 with clinical diagnosis of nonsyndromic craniosynostosis and 153 in control group) were included into the study. The following diameters were measured on head CT scans: anterior bony width (ABW), bony choanal aperture width (BCAW), right and left posterior bony width (between bone sidewall and nasal cavity septum—RPBW and LPBW). The study group has been divided into 4 categories, depending on child’s age. The dimensions measured between bone structures of nasal cavity were statistically significantly lower in comparison to the control group. They did not depend on the sex for ABW, nor on age in groups 7–12 months and < 2 years for BCAW, RPBW and LPBW. The measured dimensions increased with age. In children with nonsyndromic craniosynostosis the diameter of pyriform aperture and bony choanal aperture were lower than in controls, what may be described as fronto-orbital anomalies. Morphometric measurements of anthropometric indicators on CT scans could be used as standards in the clinical identification of craniosynostosis type and may help in planning surgical procedures, particularly in the facial skeleton in children.