Preliminary clinic study on computer assisted mandibular reconstruction: the positive role of surgical navigation technique

Application of a modified osteotomy and positioning integrative template system (MOPITS) based on a truncatable reconstruction model in the precise mandibular reconstruction with fibula free flap: a pilot clinical study

BACKGROUND

Mandibular defects can greatly affect patients' appearance and functionality. The preferred method to address this issue is reconstructive surgery using a fibular flap. The current personalized guide plate can improve the accuracy of osteotomy and reconstruction, but there are still some problems such as complex design process and time-consuming. Therefore, we modified the conventional template to serve the dual purpose of guiding the mandible and fibula osteotomy and facilitating the placement of the pre-bent titanium.

METHODS

The surgery was simulated preoperatively using Computer-Aided Design (CAD) technology. The template and truncatable reconstruction model were produced in the laboratory using 3D printing. After pre-bending the titanium plate according to the contour, the reconstruction model was truncated and the screw trajectory was transferred to form a modified osteotomy and positioning integrative template system (MOPITS). Next, the patient underwent a composite template-guided vascularized fibula flap reconstruction of the mandible. All cases were reviewed for the total operative time and accuracy of surgery.

RESULTS

The procedures involved 2-4 fibular segments in 15 patients, averaging 3 fibular segments per procedure. The osteotomy error is 1.01 ± 1.02 mm, while the reconstruction angular error is 1.85 ± 1.69°. The preoperative and postoperative data were compared, and both p > 0.05. During the same operation, implant placement was performed on four patients, with an average operative time of 487.25 ± 60.84 min. The remaining malignant tumor patients had an average operative time of 397.18 ± 73.09 min. The average postoperative hospital stay was 12.95 ± 3.29 days.

CONCLUSIONS

This study demonstrates the effectiveness of MOPITS in facilitating precise preoperative planning and intraoperative execution of fibula flap reconstruction. MOPITS represents a promising and reliable tool for reconstructive surgery, particularly for inexperienced surgeons navigating the challenges of mandible defect reconstruction.

Non-operative adjuncts for the prevention of mastectomy skin flap necrosis: a systematic review and meta-analysis

BACKGROUND

Native skin flap necrosis is a potentially devastating complication following skin-sparing or nipple-sparing mastectomy with a reported incidence of as high as 30%. Treatment depends on the depth and extent of tissue necrosis and can range from dressings to surgical debridement and further reconstruction. This can have implications on patient physical and psychological wellbeing as well as cost of treatment. This study aims to identify and appraise cost-effective non-surgical adjuncts for the prevention of native skin flap necrosis.

METHODS

A systematic review was performed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and structured around existing recommended guidelines. A search of MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and ClinicalTrials.gov was performed with the medical subject headings 'mastectomy' and 'flap necrosis'. After exclusion, 12 articles were selected for review and analysed.

RESULTS

A total of 8439 mastectomies were performed on 7895 patients. Preventative non-surgical adjuncts that demonstrated statistically significant reduction in mastectomy flap necrosis included topical nitroglycerin ointment (P = 0.000), closed-Incision negative pressure wound therapy (P = 0.000), topical dimethylsulfoxide ointment (P = 0.03), oral cilostazol (P = 0.032), and local heat pre-conditioning (P = 0.047).

CONCLUSIONS

This study identifies multiple adjuncts that may aid in preventing mastectomy skin flap necrosis, especially in high-risk patients. Further studies could aim to define standardized protocols and compare the various adjuncts in different circumstances.

Accuracy of Mixed Reality Combined With Surgical Navigation Assisted Oral and Maxillofacial Tumor Resection

OBJECTIVE

To evaluate the feasibility and accuracy of mixed reality combined with surgical navigation in oral and maxillofacial tumor surgery.

METHODS

Retrospective analysis of data of seven patients with oral and maxillofacial tumors who underwent surgery between January 2019 and January 2021 using a combination of mixed reality and surgical navigation. Virtual surgical planning and navigation plan were based on preoperative CT datasets. Through IGT-Link port, mixed reality workstation was synchronized with surgical navigation, and surgical planning data were transferred to the mixed reality workstation. Osteotomy lines were marked with the aid of both surgical navigation and mixed reality images visualized through HoloLens. Frozen section examination was used to ensure negative surgical margins. Postoperative CT datasets were obtained 1 week after the surgery, and chromatographic analysis of virtual osteotomies and actual osteotomies was carried out. Patients received standard oncological postoperative follow-up.

RESULTS

Of the seven patients, four had maxillary tumors and three had mandibular tumors. There were total of 13 osteotomy planes. Mean deviation between the planned osteotomy plane and the actual osteotomy plane was 1.68 ± 0.92 mm; the maximum deviation was 3.46 mm. Chromatographic analysis showed error of ≤3 mm for 80.16% of the points. Mean deviations of maxillary and mandibular osteotomy lines were approximate (1.60 ± 0.93 mm vs. 1.86 ± 0.93 mm). While five patients had benign tumors, two had malignant tumors. Mean deviations of osteotomy lines was comparable between patients with benign and malignant tumors (1.48 ± 0.74 mm vs. 2.18 ± 0.77 mm). Intraoperative frozen pathology confirmed negative resection margins in all cases. No tumor recurrence or complications occurred during mean follow-up of 15.7 months (range, 6-26 months).

CONCLUSION

The combination of mixed reality technology and surgical navigation appears to be feasible, safe, and effective for tumor resection in the oral and maxillofacial region.

Computer-Aided Design and Manufacturing versus Conventional Surgical Planning for Head and Neck Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Virtual surgical planning and computer-aided design/computer-aided manufacturing (CAD/CAM) for complex head and neck reconstruction has a number of cited advantages over conventional surgical planning, such as increased operative efficiency, fewer complications, improved osseous flap union, immediate osseointegrated dental implant placement, and superior functional and aesthetic outcomes. The authors performed a systematic review and meta-analysis of the available evidence on CAD/CAM maxillofacial reconstruction with the primary purpose of determining which approach is more efficacious.

METHODS

In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a PubMed and Embase database search was performed to identify English-language, human-subject studies of CAD/CAM-assisted head and neck reconstruction. All comparative studies were included in a meta-analysis to identify differences in operative time, ischemia time, surgical-site occurrence, microvascular complication, and partial or total flap loss between the two groups. All included studies (comparative and noncomparative) were used in the systematic review, summarizing the various flap characteristics, technical nuances, and functional and aesthetic outcomes.

RESULTS

Twelve articles were included in the meta-analysis, representing 277 patients in the CAD/CAM group and 419 patients in the conventional group. CAD/CAM was associated with 65.3 fewer minutes of operating room time (95 percent CI, -72.7 to -57.9 minutes; p < 0.0001) and 34.8 fewer minutes of ischemia time (95 percent CI, -38 to -31.5 minutes; p < 0.0001). There were no significant differences in surgical-site occurrence, nonunion, flap loss, microvascular complications, or hardware-related complications.

CONCLUSIONS

CAD/CAM is associated with shorter operating room and ischemia times. There are no significant differences in flap or hardware-related complications between CAD/CAM and conventional surgical planning.

Accuracy of Fibula Reconstruction Using Patient-Specific Cad/Cam Plates: A Multicenter Study on 47 Patients

OBJECTIVES

This prospective study evaluated the accuracy of mandibular reconstruction using free fibular flaps (by comparing virtual plans to the three-dimensional postoperative results), and the extent of bone-to-bone contact after computer-assisted surgery.

METHODS

We included 65 patients who underwent partial-continuity mandibular resections from February 2013 to January 2017, and evaluated virtual planning, surgical techniques, and accuracy.

RESULTS

Forty-seven patients were analysed. A total of 112 fibular segments received 54 implants. We measured 227 distances between landmarks to assess the accuracy of reconstruction. Postoperative reconstruction accuracy ranged from 0.5 to 3 mm.

CONCLUSION

Virtual surgical planning very accurately translated simulation into reality, particularly in patients requiring large, complex mandibular reconstructions using multiple fibular segments.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2169-E2175, 2021.

Patient-Specific Mandibular Reconstruction Plates Increase Accuracy and Long-Term Stability in Immediate Alloplastic Reconstruction of Segmental Mandibular Defects

OBJECTIVES

The aim of the current study was to evaluate potential differences in the accuracy of mandibular reconstruction and long-term stability, with respect to different reconstructive procedures.

METHODS

In total, 42 patients who had undergone primary segmental mandibular resection with immediate alloplastic reconstruction, with either manually pre-bent or patient-specific mandibular reconstruction plates (PSMRP), were included in this study. Mandibular dimensions, in terms of six clinically relevant distances (capitulum [most lateral points], capitulum [most medial points], incisura [most caudal points], mandibular foramina, coronoid process [most cranial points], dorsal tip of the mandible closest to the gonion point) determined from tomographic images, were compared prior to, and after surgery.

RESULTS

Dimensional alterations were significantly more often found when conventionally bent titanium reconstruction plates were used. These occurred in the area of the coronoid process (p = 0.014). Plate fractures were significantly (p = 0.022) more often found within the manually pre-bent group than within the PSMRP group (17%/0%).

CONCLUSION

The results suggest that the use of PSMRP may prevent rotation of the proximal mandibular segment, thus avoiding functional impairment. In addition, the use of PSMRP may potentially enhance the long-term stability of alloplastic reconstructions.

Virtual Reality Simulation and Augmented Reality-Guided Surgery for Total Maxillectomy: A Case Report

With the improvement in computer graphics and sensors, technologies like virtual reality (VR) and augmented reality (AR) have created new possibilities for developing diagnostic and surgical techniques in the field of surgery. VR and AR are the latest technological modalities that have been integrated into clinical practice and medical education, and are rapidly emerging as powerful tools in the field of maxillofacial surgery. In this report, we describe a case of total maxillectomy and orbital floor reconstruction in a patient with malignant fibrous histiocytoma of the maxilla, with preoperative planning via VR simulation and AR-guided surgery. Future developments in VR and AR technologies will increase their utility and effectiveness in the field of surgery.

Three-Dimensionally Printed Patient-Specific Surgical Plates Increase Accuracy of Oncologic Head and Neck Reconstruction Versus Conventional Surgical Plates: A Comparative Study

Background

Surgeons are pursuing accurate head and neck reconstruction to enhance aesthetic and functional outcomes after oncologic resection. This study aimed to investigate whether accuracy of head and neck reconstruction is improved with the use of three-dimensionally (3D)-printed patient-specific surgical plates compared with conventional plates.

Methods

In this comparative study, patients were prospectively recruited into the study group (3DJP16) with 3D-printed patient-specific surgical plates. The patients in control group with conventional surgical plates were from a historic cohort in the same unit. The primary end point of the study was the accuracy of head and neck reconstruction. The secondary end points were accuracy of osteotomy, intraoperative blood loss, total operative time, and length of hospital stay.

Results

The study recruited of 33 patients, including 17 in the study group and 16 in the control group. The patients’ baseline characteristics were similar between the two groups. The absolute distance deviation of the maxilla or mandible was 1.5 ± 0.5 mm in the study group and 2.1 ± 0.7 mm in the control group [mean difference, − 0.7 mm; 95% confidence interval (CI) − 1.1 to − 0.3; p = 0.003], showing superior accuracy of reconstruction for the patients with 3D-printed patient-specific surgical plates. Improved accuracy of reconstruction also was detected in terms of bilateral mandibular angles and bone grafts. Concerning the secondary end points, the accuracy of the osteotomy was similar in the two groups. No difference was found regarding intraoperative blood loss, total operative time, or length of hospital stay.

Conclusions

This is the first study to prove that compared with conventional plates, 3D-printed patient-specific surgical plates improve the accuracy of oncologic head and neck reconstruction.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08732-y) contains supplementary material, which is available to authorized users.

The Shape of Things to Come: In-Hospital Three-Dimensional Printing for Mandibular Reconstruction Using Fibula Free Flap

OBJECTIVES/HYPOTHESIS

The aim of this study was to explore whether the production of in-hospital, low-cost surgical cutting guides would be possible and to assess different cutting guide shapes to facilitate the surgery and the application with instruments.

STUDY DESIGN

Cohort study.

METHODS

Using free computer-aided design software, surgical cutting guides for the mandible and fibula were designed and used to perform virtual segmental osteotomies and fibula transplants in seven patients.

RESULTS

Fourteen virtual osteotomies were performed using the free software and the proposed workflow. Thirteen guides were then printed to transfer the virtual planning information to the operating room.

CONCLUSIONS

Virtual planning and the three-dimensional (3D) printing of guides for mandibular reconstruction is reliable with the aid of an in-hospital 3D laboratory. We also demonstrated that different guides with different shapes could be produced with benefits during surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

Standardized measurement of auricle: A method of high-precision and reliability based on 3D scanning and Mimics software

Objective measurement is important for diagnosing congenital or acquired auricular abnormalities and the evaluation of therapeutic efficacy. However, methods applied in the past were mostly inaccurate and unreliable. The present study aimed to introduce five standardized indices for auricle measurement and present a highly precise and reliable methodology combining three-dimensional (3D) scanning techniques and the Materialise Mimics software for the evaluation of auricle sizes. A total of 20 normal ears were measured independently by four surgeons using the standardized digital method with 3D scanning technique and the traditional manual method. Parameters of the auricle, including the length and width, arc length, cranioauricular height and angle were measured using the Mimics software. Paired t-test, Wilcoxon signed rank test and intra-class correlation coefficients (ICC) were performed on the data to assess the precision, uniformity and observer independence of the method. Pearson's product moment correlation was calculated to assess the correlation between auricle length and width in addition to the correlation between cranioauricular height and angle. No significant differences were indicated between measurements of five auricular parameters made by two surgeons using the digital method. However, significant differences were found using the manual method (P<0.01). ICC values derived from digital measurements ranged from 0.901 to 0.987, whereas those derived from manual measurements ranged from 0.526 to 0.807. These results suggested that the standardized digital method was replicable and reliable compared with the traditional manual method. Pearson's coefficient analysis showed that there was a significant correlation between cranioauricular height and angle (P<0.05), but no correlations were found between the height and width of the auricle (P>0.05). Taken together, data from the present study suggested that measurements of the length and width, arch length, and cranioauricular height and angle of auricles using the standardized digital method combining 3D scanning with the Mimics software were comprehensive, precise, convenient, repeatable and reliable.

Virtual surgical planning in fibula free flap head and neck reconstruction: A systematic review and meta-analysis

BACKGROUND

The traditional approach to head and neck reconstruction is considered challenging, requiring a subjective assessment of an often-complex defect followed by careful modelling of a bony flap to match this. The introduction of Virtual Surgical Planning (VSP) has provided the surgeon with a means to increase efficiency, precision and overall patient outcomes. This study aims to compare VSP and traditional head and neck reconstructions utilising fibula free flaps with regards surgical efficiency and patient outcomes.

METHODS

A systematic search of the PubMed and Medline databases was performed from the date of their inception through to August 2018 to evaluate and compare VSP and non-VSP cohorts in the context of fibula free flap head and neck reconstruction. Primary comparative outcomes included operative and ischaemic time, with secondary outcomes including complications rates, measures of accuracy and financial benefits.

RESULTS

One hundred and fifty-three articles were identified. Twenty-three articles were included in the review, comprising a total of 713 patients. VSP was associated with significantly decreased intraoperative time (Standardised Mean Difference -1.01; 95% CI -1.23 to 0.80; p = 0.000) and ischaemic time (Standardised Mean Difference -1.55; 95% CI -1.87 to -1.23, p = 0.002). VSP was also associated with reduced orthognathic deviation from an ideal outcome when compared to conventional techniques. No statistically significant differences in complication rates between conventional and VSP techniques were identified.

CONCLUSION

The results of this meta-analysis suggests that VSP confers significant benefits with respect to improved orthognathic accuracy, ischaemic times and intraoperative times without any significant increase in complications. Recommendations for ongoing research are suggested.

Vascularized scapula and latissimus dorsi flap for CAD/CAM assisted reconstruction of mandibular defects including the mandibular condyle: technical report and clinical results

Background

Reconstruction of mandibular continuity and function after tumor resection is challenging, particularly in cases including the mandibular condyle. Various approaches for reconstruction after disarticulation resection have been reported. However, the scapula flap has received little attention as a treatment option in these cases.

Patients and methods

Three cases of computer aided design and computer aided manufacturing (CAD/CAM) assisted reconstruction after disarticulation resection using a vascularized scapula and latissimus dorsi flap are reported. All cases required reconstruction of the mandibular ramus and condyle in combination with the reconstruction of large and complex soft tissue defects.

Results

The surgical procedure was deemed successful in all cases. The scapula flap could be placed as preoperatively planned and patients regained their preoperative occlusion pattern and satisfying mouth opening-ranges. The large soft tissue defects could reliably be reconstructed using a latissimus dorsi flap.

Conclusions

The scapula and latissimus dorsi flap can be considered a suitable option for the reconstruction of mandibular disarticulation resection defects in combination with large soft tissue defects.

Accuracy of computer-assisted surgery in mandibular reconstruction: A systematic review

Computer-assisted surgery (CAS) for mandibular reconstruction was developed to improve conventional treatment methods. In the past years, many different software programs have entered the market, offering numerous approaches for preoperative planning and postoperative evaluation of the CAS process of mandibular reconstruction. In this systematic review, we reviewed planning and evaluation methods in studies that quantitatively assessed accuracy of mandibular reconstruction performed with CAS. We included 42 studies describing 413 mandibular reconstructions planned and evaluated using CAS. The commonest software was Proplan/Surgicase CMF (55%). In most cases, the postoperative virtual 3-dimensional model was compared to the preoperative 3-dimensional model, revised to the virtual plan (64%). The commonest landmark for accuracy measurements was the condyle (54%). Accuracy deviations ranged between 0 mm and 12.5 mm and between 0.9° and 17.5°. Because of a lack of uniformity in planning (e.g., image acquisition, mandibular resection size) and evaluation methodologies, the ability to compare postoperative outcomes was limited; meta-analysis was not performed. A practical and simple guideline for standardizing planning and evaluation methods needs to be considered to allow valid comparisons of postoperative results and facilitate meta-analysis in the future.

Designing CAD/CAM Surgical Guides for Maxillary Reconstruction Using an In-house Approach

Computer-aided design/computer-assisted manufacturing (CAD/CAM) is now being evaluated as a preparative technique for maxillofacial surgery. Because this technique is expensive and available in only limited areas of the world, we developed a novel CAD/CAM surgical guide using an in-house approach. By using the CAD software, the maxillary resection area and cutting planes and the fibular cutting planes and angles are determined. Once the resection area is decided, the necessary faces are extracted using a Boolean modifier. These superficial faces are united to fit the surface of the bones and thickened to stabilize the solids. Not only the cutting guides for the fibula and maxilla but also the location arrangement of the transferred bone segments is defined by thickening the superficial faces. The CAD design is recorded as .stl files and three-dimensionally (3-D) printed as actual surgical guides. To check the accuracy of the guides, model surgery using 3-D-printed facial and fibular models is performed. These methods may be used to assist surgeons where commercial guides are not available.

Navigation Guidance During Free Flap Mandibular Reconstruction: A Cadaveric Trial

Importance

Segmental mandibulectomy for tumors that distort the buccal surface of the mandible present a reconstructive challenge.

Objective

To determine whether mandible alignment after navigation-guided mandible reconstruction is better than alignment after non-template-assisted freehand reconstruction and as good as template-assisted reconstruction in a cadaveric trial.

Design, Setting, and Participants

A cadaveric trial using 10 specimens was conducted at a tertiary academic center. Fiducials were created on the ramus to compare alignment with each intervention. Segmental mandibulectomy was performed on each cadaver. Each cadaver underwent navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction with plate contouring performed after mandibulectomy. The study was conducted from October 1, 2015, to January 1, 2016; data analysis was performed from February 1, 2016, to March 1, 2016.

Interventions

Segmental mandibulectomy, navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction.

Main Outcomes and Measures

Ramus fiducial coordinates were recorded at baseline and after each intervention. Mandible dimensions were measured using cephalometric landmarks. Postintervention and baseline differences in ramus and mandible position were calculated.

Results

Ramus alignment was not significantly different between navigation-guided and template-assisted reconstruction, differing by 0.54 mm (98.3% CI, -0.38 to 1.47 mm). Non-template-assisted freehand reconstruction was associated with a 3.14-mm difference in alignment compared with template-assisted reconstruction (98.3% CI, 1.09 to 5.19 mm). Navigation-guided alignment resulted in a 3.69-mm improvement in alignment compared with non-template-assisted freehand reconstruction (98.3% CI, 1.79 to 5.58 mm). There was some improvement in the gonion-gonion and lingula mandibulae-lingula mandibulae (Lm-Lm) alignment for navigation-assisted compared with non-template-assisted freehand reconstruction by 1.97 mm (98.3% CI, -0.65 to 4.58 mm) and 1.39 mm (98.3% CI, -0.17 to 2.95 mm), respectively. There was marginal evidence of better Lm-Lm alignment for navigation-guided than template-assisted reconstruction (0.44 mm; 98.3% CI, -0.06 to 0.95 mm).

Conclusions and Relevance

Mandible alignment following navigation-guided reconstruction is similar to template-assisted reconstruction. Navigation-guided alignment is likely better than non-template-assisted freehand reconstruction, and navigation guidance offers a reliable technique for real-time adjustment when reconstructing complex surgical defects, such as tumors effacing the buccal cortex of the mandible.

Intraoperative navigation in complex head and neck resections: indications and limits

PURPOSE

The surgical removal of head and neck tumors often represents a highly complex surgery. The three-dimensionality and the anatomy of the head and neck area make sometimes difficult a correct intraoperative orientation and the obtaining of an adequate oncological safety. In the present pilot study, the authors propose a protocol of application of intraoperative navigation in the resection of head and neck tumors. The purpose is to develop a methodology that can be helpful to ensure oncologic free margins of resection and to facilitate the orientation of the specimen by pathologists.

MATERIALS AND METHODS

A sample of 16 patients with head and neck tumors was selected, and they were differentiated into two groups: a "study group" treated with CT computer-assisted surgery and a "control group" surgically treated without the use of technology. The following data were analyzed: operative and pre-surgical planning times, issues related to the use of the technologies, respect of the planned landmarks, description and orientation of the surgical specimen and distance of the tumor from the margins of resection.

RESULTS

In the "study group" were noticed a reduced rate of errors in the specimen orientation and an increased distance of the tumor from the margins of resection. Similar operative times were observed in both groups.

CONCLUSIONS

Intraoperative navigation resulted to be a reliable method to improve oncological safety in a selected group of patients.

Low-cost Design and Manufacturing of Surgical Guides for Mandibular Reconstruction Using a Fibula

Background:

Surgical cutting guides are used in mandibular reconstruction involving osteotomy of the mandible and fibula. Cutting guides produced using computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies have been reported recently. These guides aim to increase the benefits to patients by improving the accuracy, shortening the operating time, and correcting occlusion. However, the availability of these advanced technologies is limited in some regions of the world. To test whether we could produce low-cost surgical cutting guides, we made surgical guides and investigated their accuracy.

Methods:

Using free CAD software, we designed surgical cutting guides for the mandible and fibula and used these to perform virtual mandibular segmental osteotomies and fibula transplants in 12 model surgeries. The cutting guides were printed on a 3-dimensional (3D) printer. The model surgeries were performed using 3D mandibular models and cutting guides to check their accuracy. Deviations between the virtually simulated plan and the actual model surgery were investigated.

Results:

CAD and CAM technologies were used to design and 3D print the cutting guides and models. The guided surgeries were performed. The deviations were about 1.3 mm for mandibular osteotomy, less than 1 mm for fibular osteotomy, and within 2.4 mm for reconstructions of the mandible.

Conclusions:

Without using expensive software or products, we were able to design surgical cutting guides for the mandible and fibula and used these to perform virtual simulation of mandibular segmental osteotomy and fibular reconstruction. Model surgeries using 3D-printed surgical guides showed that the accuracy of reconstruction was within a 3-mm deviation. In circumstances where commercial CAD/CAM guides are not available, it may be possible to use CAD/CAM surgical guides in the clinic if doctors are willing to volunteer their time for the design and printing.