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

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.

Patient-specific Composite Anatomic Models: Improving the Foundation for Craniosynostosis Repair

Preoperative surgical planning incorporating computer-aided design and manufacturing is increasingly being utilized today within the fields of craniomaxillofacial, orthopedic, and neurosurgery. Application of these techniques for craniosynostosis reconstruction can include patient-specific anatomic reference models, "normal" reference models or patient-specific cutting/marking guides based on the presurgical plan. The major challenge remains the lack of tangible means to transfer the preoperative plan to the operating table. We propose a simple solution to utilize a digitally designed, 3D-printed "composite model" as a structural template for cranial vault reconstruction. The composite model is generated by merging the abnormal patient cranial anatomy with the "dural surface topography" of an age-matched, sex-matched, and ethnicity-matched normative skull model. We illustrate the applicability of this approach in 2 divergent cases: 22-month-old African American male with sagittal synostosis and 5-month-old White male with metopic synostosis. The aim of this technical report is to describe our application of this computer-aided design and modeling workflow for the creation of practical 3D-printed skulls that can serve as intraoperative frameworks for the correction of craniosynostosis. With success in our first 2 cases, we believe this approach of a composite model is another step in reducing our reliance on subjective guesswork, and the fundamental aspect of the workflow has a wider application within the field of craniofacial surgery for both clinical patient care and education.

Standardized and axially vascularized calcium phosphate-based implants for segmental mandibular defects: A promising proof of concept

The reconstruction of massive segmental mandibular bone defects (SMDs) remains challenging even today; the current gold standard in human clinics being vascularized bone transplantation (VBT). As alternative to this onerous approach, bone tissue engineering strategies have been widely investigated. However, they displayed limited clinical success, particularly in failing to address the essential problem of quick vascularization of the implant. Although routinely used in clinics, the insertion of intrinsic vascularization in bioengineered constructs for the rapid formation of a feeding angiosome remains uncommon. In a clinically relevant model (sheep), a custom calcium phosphate-based bioceramic soaked with autologous bone marrow and perfused by an arteriovenous loop was tested to regenerate a massive SMD and was compared to VBT (clinical standard). Animals did not support well the VBT treatment, and the study was aborted 2 weeks after surgery due to ethical and animal welfare considerations. SMD regeneration was successful with the custom vascularized bone construct. Implants were well osseointegrated and vascularized after only 3 months of implantation and totally entrapped in lamellar bone after 12 months; a healthy yellow bone marrow filled the remaining space. STATEMENT OF SIGNIFICANCE: Regenerative medicine struggles with the generation of large functional bone volume. Among them segmental mandibular defects are particularly challenging to restore. The standard of care, based on bone free flaps, still displays ethical and technical drawbacks (e.g., donor site morbidity). Modern engineering technologies (e.g., 3D printing, digital chain) were combined to relevant surgical techniques to provide a pre-clinical proof of concept, investigating for the benefits of such a strategy in bone-related regenerative field. Results proved that a synthetic-biologics-free approach is able to regenerate a critical size segmental mandibular defect of 15 cm³ in a relevant preclinical model, mimicking real life scenarii of segmental mandibular defect, with a full physiological regeneration of the defect after 12 months.

"Black bone": the new backbone in CAD/CAM-assisted craniosynostosis surgery?

BACKGROUND

Computer-assisted design and manufacturing (CAD/CAM) techniques have been implemented in craniosynostosis surgery to facilitate cranial remodeling. However, until now, computed tomography (CT) scans with ionizing radiation were necessary to plan the procedure and create guiding templates. The purpose of this study was to present our series using CAD/CAM techniques in planning and conducting fronto-orbital advancement surgery in patients with trigonocephaly with datasets acquired only by "black bone" magnetic resonance imaging (MRI).

METHODS

Six consecutively operated cases from 2019 were included in this study. All patients suffered from non-syndromic trigonocephaly with no primary surgeries. All patients underwent cranial MRI including black bone sequences. Preoperative planning and guides were created based on the DICOM datasets. We analyzed demographic data, clinical data, and outcome measured by Whitaker score.

RESULTS

In all cases, precise frontobasal advancement was possible with the CAD/CAM guides created by black bone MRI. The mean operation time and planning time were 222 and 32 min. The time on intensive and intermediate care unit (ICU/IMC) time was 4.5 days, respectively. All but one case were classified as Whitaker I.

CONCLUSION

In trigonocephaly treatment by frontobasal advancement, black bone MRI-based CAD/CAM craniosynostosis surgery is safe and feasible. It offers the major advantage of completely avoiding CT scans and ionizing radiation with superior imaging quality of intracranial structures. Thus, it improves intraoperative safety and-at the same time-has the potential to reduce operating room (OR) time.

Is reverse frontal cranioplasty eligible for the correction of both the forehead deformities and the intracranial hypertension in craniosynostosis? Comparison of the preoperative and postoperative intracranial volumes

BACKGROUND

This study aimed to describe the surgical technique of reverse frontal cranioplasty (RFC), the aesthetical modification as well as the modification of intracranial volume (ICV) to assess its potential eligibility for the treatment of the intracranial hypertension (IH).

MATERIALS AND METHODS

A retrospective monocentric study included the patients with a history of craniosynostosis with a forehead deformity who underwent RFC. A subjective outcome questionnaire (SOQ) was conducted with each patient or their parent to determine their level of satisfaction after RFC. Pre- and postoperative computed tomography (CT) scans were analyzed and compared to investigate the ICV change and fronto-nasal angle.

RESULTS

Eleven patients were included in the study (6 female and 5 male) with a mean age of 10.9 years old (range 3-23 years) and an average follow-up of 4.5 years (1-11 years). All patients responded to the questionnaire with a high level of overall satisfaction (mean 9.1/10). The mean preoperative FNA was 134° ± 5° while the mean postoperative angle was 126.4° ± 6, corresponding to an average decrease of 7.6° (95% CI, 4.0-11.2°; p < 0.001). One patient with preoperative IH had a clinical recurrence during the follow-up. The ICV was significantly higher after the surgery (p < 0.0001), with an average increase of 3.2% (95% CI, 2.3-4.1%).

CONCLUSION

Reverse (RFC) is a useful technique for the correction of the frontal malformations related to craniosynostosis, such as a sloping forehead and/or a lack of the supraorbital projection. Regarding the limited gain of intracranial volume (ICV), it should not be used alone as primary cranial expansion surgery for craniosynostosis with intracranial hypertension (IH).

The need for overcorrection: evaluation of computer-assisted, virtually planned, fronto-orbital advancement using postoperative 3D photography

OBJECTIVE

The main indication for craniofacial remodeling of craniosynostosis is to correct the deformity, but potential increased intracranial pressure resulting in neurocognitive damage and neuropsychological disadvantages cannot be neglected. The relapse rate after fronto-orbital advancement (FOA) seems to be high; however, to date, objective measurement techniques do not exist. The aim of this study was to quantify the outcome of FOA using computer-assisted design (CAD) and computer-assisted manufacturing (CAM) to create individualized 3D-printed templates for correction of craniosynostosis, using postoperative 3D photographic head and face surface scans during follow-up.

METHODS

The authors included all patients who underwent FOA between 2014 and 2020 with individualized, CAD/CAM-based, 3D-printed templates and received postoperative 3D photographic face and head scans at follow-up. Since 2016, the authors have routinely planned an additional "overcorrection" of 3 mm to the CAD-based FOA correction of the affected side(s). The virtually planned supraorbital angle for FOA correction was compared with the postoperative supraorbital angle measured on postoperative 3D photographic head and face surface scans. The primary outcome was the delta between the planned CAD/CAM FOA correction and that achieved based on 3D photographs. Secondary outcomes included outcomes with and those without "overcorrection," time of surgery, blood loss, and morbidity.

RESULTS

Short-term follow-up (mean 9 months after surgery; 14 patients) showed a delta of 12° between the planned and achieved supraorbital angle. Long-term follow-up (mean 23 months; 8 patients) showed stagnant supraorbital angles without a significant increase in relapse. Postsurgical supraorbital angles after an additionally planned overcorrection (of 3 mm) of the affected side showed a mean delta of 11° versus 14° without overcorrection. The perioperative and postoperative complication rates of the whole cohort (n = 36) were very low, and the mean (SD) intraoperative blood loss was 128 (60) ml with a mean (SD) transfused red blood cell volume of 133 (67) ml.

CONCLUSIONS

Postoperative measurement of the applied FOA on 3D photographs is a feasible and objective method for assessment of surgical results. The delta between the FOA correction planned with CAD/CAM and the achieved correction can be analyzed on postoperative 3D photographs. In the future, calculation of the amount of "overcorrection" needed to avoid relapse of the affected side(s) after FOA may be possible with the aid of these techniques.