Virtual modeling, stereolithography, and intraoperative CT guidance for the optimization of sagittal synostosis reconstruction: a technical note

Barriers of Three-Dimensional Printing in Craniofacial Plastic Surgery Practice: A Pilot Study and Literature Review

OBJECTIVE

Three-dimensional printing (3Dp) and modeling have demonstrated increasing utility within plastic and reconstructive surgery (PRS). This study aims to understand the prevalence of how this technology is utilized in craniofacial surgery, as well as identify barriers that may limit its integration into practice.

METHODS

A survey was developed to assess participant demographics, characteristics of 3Dp use, and barriers to utilizing three-dimensional technologies in practice. The survey was distributed to practicing craniofacial surgeons. A secondary literature review was conducted to identify solutions for barriers and potential areas for innovation.

RESULTS

Fifteen complete responses (9.7% response rate) were analyzed. The majority (73%) reported using three-dimensional modeling and printing in their practice, primarily for surgical planning. The majority (64%) relied exclusively on outside facilities to print the models, selecting resources required to train self and staff (55%), followed by the cost of staff to run the printer (36%), as the most common barriers affecting 3Dp use in their practice. Of those that did not use 3Dp, the most common barrier was lack of exposure (75%). The literature review revealed cost-lowering techniques with materials, comparability of desktop commercial printers to industrial printers, and incorporation of open-source software.

CONCLUSIONS

The main barrier to integrating 3Dp in craniofacial plastic and reconstructive surgery practice is the perceived cost associated with utilizing the technology. Ongoing literature highlights the cost-utility of in-house 3Dp technologies and practical cost-saving methods. The authors' results underscore the need for broad exposure for currently practicing attendings and trainees in 3Dp practices and other evolving technologies.

Computed Tomography in Patients With Craniosynostosis: A Survey to Ascertain Practice Patterns Among Craniofacial Surgeons

BACKGROUND

In patients with craniosynostosis, imaging remains up to the discretion of the plastic surgeon or neurosurgeon. To inform best practice guidelines, we sought to obtain data surrounding the frequency at which craniofacial surgeons order computed tomography (CT), as well as indications. We hypothesized that we would identify considerable variation in both imaging and associated indications.

METHODS

We surveyed members of the American Society of Maxillofacial Surgeons and the American Society of Craniofacial Surgeons to measure the frequency of preoperative and postoperative head CTs, as well as indications. Initial items were piloted with 2 craniofacial surgeons and 1 neurosurgeon, using interviews to ensure content validity. χ2 Tests were used to measure associations between operative volume, years in practice, and imaging.

RESULTS

Eighty-five craniofacial surgeons responded (13.8% response rate), with the majority (63.5%) having performed a craniosynostosis operation in the last month. Only 9.4% of surgeons never order preoperative CTs. Of those who do, the most common indications included diagnosis confirmation (31.2%) and preoperative planning (27.3%). About 25% of surgeons always obtain postoperative head CTs, usually to evaluate surgical outcomes (46.7%). Only 13.3% of respondents order 2 or more postoperative scans. Higher operative volume was associated with a lower likelihood of ordering preoperative head CTs (P = 0.008).

CONCLUSIONS

The majority of surgeons obtain preoperative head CTs, whereas only 25% obtain CTs postoperatively, often to evaluate outcomes. Because outcomes may be evaluated clinically, this is a poor use of resources and exposes children to radiation. Consensus guidelines are needed to create best practices and limit unnecessary studies.

Three-dimensional printing and craniosynostosis surgery

OVERVIEW

The goal of this study was to review the current application and status of three-dimensional printing for craniosynostosis surgery.

METHODS

A literature review was performed using the PubMed/MEDLINE databases for studies published between 2010 and 2020. All studies demonstrating the utilization of three-dimensional printing for craniosynostosis surgery were included.

RESULTS

A total of 15 studies were ultimately selected. This includes studies demonstrating novel three-dimensional simulation and printing workflows, studies utilizing three-dimensional printing for surgical simulation, as well as case reports describing prior experiences.

CONCLUSION

The incorporation of three-dimensional printing into the domain of craniosynostosis surgery has many potential benefits. This includes streamlining surgical planning, developing patient-specific template guides, enhancing residency training, as well as aiding in patient counseling. However, the current state of the literature remains in the validation stage. Further study with larger case series, direct comparisons with control groups, and prolonged follow-up times is necessary before more widespread implementation is justified.

Three-dimensional photography for intraoperative morphometric analysis in metopic craniosynostosis surgery

PURPOSE

Surgical correction of metopic craniosynostosis typically involves open cranial vault remodeling. Accurate translation of the virtual surgical plan into the operating room is challenging due to the lack of tools for intraoperative analysis of the surgical outcome. This study aimed to evaluate the feasibility of using a hand-held 3D photography device for intraoperative evaluation and guidance during cranial vault surgical reconstruction.

METHODS

A hand-held structured light scanner was used for intraoperative 3D photography during five craniosynostosis surgeries, obtaining 3D models of skin and bone surfaces before and after the remodeling. The accuracy of this device for 3D modeling and morphology quantification was evaluated using preoperative computed tomography imaging as gold-standard. In addition, the time required for intraoperative 3D photograph acquisition was measured.

RESULTS

The average error of intraoperative 3D photography was 0.30 mm. Moreover, the interfrontal angle and the transverse forehead width were accurately measured in the 3D photographs with an average error of 0.72 degrees and 0.62 mm. Surgeon's feedback indicates that this technology can be integrated into the surgical workflow without substantially increasing surgical time.

CONCLUSION

Hand-held 3D photography is an accurate technique for objective quantification of intraoperative cranial vault morphology and guidance during metopic craniosynostosis surgical reconstruction. This noninvasive technique does not substantially increase surgical time and does not require exposure to ionizing radiation, presenting a valuable alternative to computed tomography imaging. The proposed methodology can be integrated into the surgical workflow to assist during cranial vault remodeling and ensure optimal surgical outcomes.

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.

Craniosynostosis surgery: workflow based on virtual surgical planning, intraoperative navigation and 3D printed patient-specific guides and templates

Craniosynostosis must often be corrected using surgery, by which the affected bone tissue is remodeled. Nowadays, surgical reconstruction relies mostly on the subjective judgement of the surgeon to best restore normal skull shape, since remodeled bone is manually placed and fixed. Slight variations can compromise the cosmetic outcome. The objective of this study was to describe and evaluate a novel workflow for patient-specific correction of craniosynostosis based on intraoperative navigation and 3D printing. The workflow was followed in five patients with craniosynostosis. Virtual surgical planning was performed, and patient-specific cutting guides and templates were designed and manufactured. These guides and templates were used to control osteotomies and bone remodeling. An intraoperative navigation system based on optical tracking made it possible to follow preoperative virtual planning in the operating room through real-time positioning and 3D visualization. Navigation accuracy was estimated using intraoperative surface scanning as the gold-standard. An average error of 0.62 mm and 0.64 mm was obtained in the remodeled frontal region and supraorbital bar, respectively. Intraoperative navigation is an accurate and reproducible technique for correction of craniosynostosis that enables optimal translation of the preoperative plan to the operating room.

Computer-Assisted Design and Manufacturing Assists Less Experienced Surgeons in Achieving Equivalent Outcomes in Cranial Vault Reconstruction

PURPOSE

The purpose of this study was to assess whether long-term outcomes were equivalent between computer-assisted design and manufacturing (CAD/CAM) -assisted cranial vault reconstruction performed by an inexperienced surgeon, with fewer years of surgical experience, and traditional reconstruction performed by senior surgeons with many decades of experience.

METHODS

An Institutional Review Board-approved retrospective cohort study was performed for all patients with nonsyndromic craniosynostosis between the ages of 1 month to 18 years who received primary, open calvarial vault reconstruction at the Johns Hopkins Hospital between 1990 and 2017. The primary outcome variable was the Whitaker category (I-IV) for level of required revision at the 2-year follow-up visit. Secondary outcomes included estimated blood loss, length of stay, operative time, and postoperative complications. CAD/CAM-assisted surgery was considered noninferior if the proportion of cases requiring any revision (Whitaker II, III, or IV) was no more than 10% greater than the proportion in the traditional surgery group with multivariate logistic regression analysis. t tests and fisher exact tests were used for secondary outcomes.

RESULTS

A total of 335 patients were included, with 35 CAD/CAM-assisted reconstructions. CAD/CAM-assisted reconstruction was noninferior to traditional after accounting for patient demographics, type of surgery, and experience level of the plastic surgeon. The traditional group required revision more frequently at 29.0% compared to CAD/CAM at 14.3%. Secondary outcomes were not significantly different between groups, but CAD/CAM had significantly longer average operative times (5.7 hours for CAD/CAM, 4.3 hours for traditional, P < 0.01).

CONCLUSION

CAD/CAM technology may lower the learning curve and assist less experienced plastic surgeons in achieving equivalent long-term outcomes in craniofacial reconstruction.

Variation in the Utilization of Postoperative Computed Tomography for Patients With Nonsyndromic Craniosynostosis: A National Claims Analysis

OBJECTIVE

Routine postoperative computed tomography (CT) imaging in nonsyndromic craniosynostosis remains controversial due to the hazards of radiation exposure. The extent to which postoperative head CTs are performed remains unknown. Therefore, we sought to measure the use of postoperative CTs in this population.

DESIGN

The authors reviewed insurance claims from OptumInsight, using Current Procedural Terminology codes to identify procedures and postoperative imaging. Multilevel logistic regression was used to describe the odds of undergoing postoperative CTs, adjusting for patient and provider covariates.

PARTICIPANTS

Craniosynostosis patients who underwent reconstruction between 2001 and 2017 were reviewed. Patients older than 5 years at surgery, postoperative lengths of stay >15 days, syndromic diagnoses, operative complications within 30 days of surgery, and cranial bone grafting merited exclusion.

MAIN OUTCOME MEASURE

Odds of postoperative head CTs after cranial vault reconstruction.

RESULTS

In this cohort (n = 1150), 326 (28.4%) patients underwent postoperative head CTs. The number of CTs ranged from 0 to 14. Older age at surgery (odds ratio [OR]: 1.32, P = .002), increasing years of follow-up (OR: 1.12, P < .001), and increasing comorbidities (OR: 1.21, P = .017) were associated with postoperative CTs. After adjusting for patient factors, provider factors accounted for 31.3% of variation in imaging.

CONCLUSIONS

Over a quarter of patients underwent head CTs following reconstruction, and provider factors accounted for a large percentage of the variation. Given the risks of radiation, neurosurgeons and craniofacial surgeons face a critical need to establish postoperative imaging protocols to reduce unnecessary imaging in these vulnerable patients.