Updates in Head and Neck Reconstruction

Implementation of In-house Computer-aided Design and Manufacturing for Accelerated Free Fibula Flap Reconstruction of Mandibular Defects in Cancer Patients

Background

Computer-aided design and manufacturing (CAD/CAM) is widely adopted for optimizing microsurgical reconstruction of mandibular defects. However, commercial solutions are hampered by costs and lengthy lead times, with the latter being problematic in cancer surgery. This study aimed to investigate the efficiency of an in-house CAD/CAM service for expeditious planning and execution of free fibula mandibular reconstruction in head and neck cancer patients.

Methods

This retrospective cohort study compared cancer patients undergoing segmental mandibulectomy and immediate free fibula flap reconstruction treated before and after implementation of in-house CAD/CAM. The primary endpoint was treatment delay from preoperative consultation to surgery. Cases in the two groups were matched on the number of fibula segments required for mandibular reconstruction. The control group underwent segmental mandibulectomy and fibula flap reconstruction by "freehand." The CAD/CAM group underwent preoperative virtual surgical planning and CAD/CAM of intraoperative cutting guides for the mandibulectomy and fibula osteotomies. Outcomes were compared with the unpaired t test or Wilcoxon rank-sum test.

Results

Sixteen patients were included in both groups. Treatment delay did not increase after implementation of in-house CAD/CAM with a median 6 (range 6-20) days wait in the CAD/CAM group and 8 (6-20) days wait in the control group (P = 0.48). Utilization of CAD/CAM significantly reduced fibula flap ischemia time with a mean of 18.4 [95% confidence interval 2.8; 33.9] minutes (P = 0.022).

Conclusions

In-house CAD/CAM was implemented for free fibula flap mandibular reconstruction in head and neck cancer patients without causing treatment delay. Furthermore, CAD/CAM reduced fibula flap ischemia time.

Microvascular Free-Flap Head and Neck Reconstruction: The Utility of the Modified Frailty Five-Item Index

BACKGROUND

 Microvascular free tissue transfer is a common tool for the reconstruction of oncologic head and neck defects. Adequate preoperative assessment can aid in appropriate risk stratification and peri-operative optimization. The modified five-item frailty index (mFI-5) is a validated risk-assessment scale; however, its utility in head and neck free-flap reconstruction is unknown when compared with other common risk factors.

METHODS

 A retrospective, single-institution chart review (2017-2020) was performed. Patient demographics, defect and repair characteristics, pre- and peri-operative factors, and flap outcomes were recorded. A high mFI-5 score was defined as greater than 2. The total score, as well as other patient factors, was correlated to postoperative flap complications.

RESULTS

 A total of 214 patients were deemed appropriate for conclusion. The mean age was 63.9 ± 12.8 years. There were an even number of males (52.8%) and females (47.2%). A fifth of subjects (20.8%) underwent preoperative radiotherapy. There were 21 cases (9.8%) of complete flap loss. A total of 34 patients (29.4%) experienced any postoperative complication related to flap outcomes. An elevated mFI-5 was significantly associated with a higher overall rate of postoperative complications (39.7 vs. 29.4%, p < 0.019) and total flap loss (16.7% vs. 6.6%, p < 0.033). Preoperative radiation was found to be associated with an increased complication rate (p < 0.003).

CONCLUSION

 The mFI-5 score may be a potentially significant tool in the risk stratification of patients undergoing head and neck free-flap reconstruction as opposed to commonly utilized risk factors. Preoperative radiotherapy is significantly associated with postoperative complications. Appropriate preoperative assessment may help tailor patient care preoperatively.

Progress of Ossification after Mandibular Reconstruction by Free Fibula Flap Depending on Different Timing of Radiotherapy: A Retrospective 3D Analysis by CT Scans

Background: The aim of this study was to evaluate the difference between pre- and post-operative radiotherapy on the progress of ossification after free fibula flap reconstruction of the mandible using three-dimensional (3D) analysis. Methods: A total of 38 free fibula reconstructions of the mandible were evaluated retrospectively for ossification between bone segments by measuring Hounsfield Units (HU) in at least two postoperative computer tomography scans (average of 2.4 scans per patient; around the 5th, 12th, 16th, and 19th month postoperative). Three subgroups were created according to the time of irradiation: preoperative radiotherapy (preORT) (n = 11), postoperative radiotherapy (postORT) (n = 16), and patients without any radiation therapy (n = 11) as the control group (noRT). HU in eight regions of interest (ROI) and overlapping surfaces between segments per contact point, as well as influencing factors, were analyzed. Results: The fastest progress in gain of HU ossification with a difference of 0.30 HU/day was observed in noRT compared to preORT (p = 0.002). postORT was -0.24 HU/day slower than preORT (p = 0.005). Original and grafted bone showed a significantly slower HU uptake than between two graft segments with -84.18 HU/day (p < 0.001). Moreover, a larger initial overlapping surface between the segments in cm2 resulted in a higher rise of HU/day (p < 0.001). Conclusions: 3D analysis of post-reconstructive CT scans shows prolonged ossification of mandible reconstructions by free fibula after head and neck radiation. The effect is distinct in cases with post-operative adjuvant radiotherapy. The effects of radiotherapy on ossification may be minimized by a larger initial contact surface and improved operational techniques. Moreover, HU longitudinal measurements and 3D analysis offer new perspectives for clinical evaluation of successful bony healing.

Functional and esthetic outcomes of virtual surgical planning versus the conventional technique in mandibular reconstruction with a free fibula flap: A retrospective study of 24 cases

This study aimed to compare the functional and esthetic results in patients following mandibular reconstruction with a free fibula flap (FFF) by virtual surgical planning (VSP) versus the conventional technique. Patients who had undergone mandibular reconstruction with a FFF by VSP or the conventional technique were retrospectively assessed. The two groups were compared regarding functional and esthetic variables with appropriate scales preoperatively, intraoperatively, and postoperatively. Twenty-four patients were evaluated in two groups: conventional (n = 8) and VSP (n = 16). The mean amount of mandibular asymmetry was 2.62 mm (SD = 1.59) in the conventional group and 1.19 mm (SD = 1.32) in the VSP group. Of the patients who underwent conventional surgery, 12.5% had mandibular asymmetry of <2 mm and 87.5% had asymmetry of 2-5 mm. Of the VSP patients, 61.5% had mandibular asymmetry of <2 mm and 38.5% had mandibular asymmetry of 2-5 mm (p = 0.03). The mean difference in size of mandibular angle on the surgical and control sides was not significantly different between the two groups (p = 0.62). The difference in mean length of the mandibular body on the surgical side relative to the control side was not significant between the two groups (p = 0.75). Differences in functional variables between the two groups were not significant. Within the limitation of the study, it seems that the VSP technique resulted in better facial symmetry and superior esthetic outcomes compared with the conventional technique.

Titanium plates salvage in irradiated facial areas with the lipomodeling technique

Major defects of the facial structures cause severe functional and aesthetic impairment. For composite defects with bone loss, the use of a titanium plate bridging the bony defect, associated or not to a soft tissue pedicled flap is to be considered in complex cases, or for patients with high comorbidities. The principal limit of this technique is the risk of plate exposure, especially for patients who had adjuvant radiation therapy. We present two clinical cases of patients who had a facial reconstruction using a titanium plate associated with a locoregional soft tissue flap, and who presented a near-exposed plate a few years after the first surgery and adjuvant radiation therapy. In order to prevent plate exposure, we performed several lipomodeling sessions between skin and plate. Our results are very encouraging, with no plate exposure and thickening of the soft tissues which cover the plate at 10-years follow-up. The knowledge of the possibility to use fat grafting transfer could therefore lead to a strong return to the use of titanium plates in facial reconstruction.

Sensory Outcomes for Inferior Alveolar Nerve Reconstruction with Allograft following Free Fibula Mandible Reconstruction

BACKGROUND

As patient survival with head and neck cancer has improved, treatment goals have had to evolve to focus on improving quality of life. Traditionally, patients who have undergone mandibulectomy are left with an insensate chin and lower lip secondary to resection of the inferior alveolar nerve (IAN). The purpose of this study was to critically evaluate the authors' initial experience using processed nerve allografts (PNA) for IAN reconstruction following oncologic mandibulectomy and reconstruction with free fibula osteocutaneous flaps and to assess their patients' sensory outcomes.

METHODS

The authors performed a retrospective review of the first 32 patients who underwent immediate IAN reconstruction with PNA at the time of oncologic mandibulectomy and mandible reconstruction with free fibula osteocutaneous flaps at The University of Texas M. D. Anderson Cancer Center over a 1-year period. Semmes-Weinstein filament sensory testing was conducted at multiple surgical follow-up appointments to evaluate the quality of sensory recovery.

RESULTS

Thirteen of the 32 patients underwent postoperative Semmes-Weinstein filament testing. All 13 patients demonstrated partial return of sensation. At a mean follow-up of 8.33 months, the average level of sensation was 60.93% that of the unaffected side of the lower lip.

CONCLUSIONS

Patients were consistently afforded improvement in lower lip sensation using PNA-based IAN grafting as an adjunct to free fibula-based mandible reconstruction. The procedure adds no additional surgical morbidity and has shown consistent positive results.

Navigation-guided resection of locally advanced midface malignancies. Does it improve the safety of oncologic resection?

INTRODUCTION

Treatment of malignant midface tumors is a surgical challenge with an increased difficulty to obtain free surgical margins. The computer assisted surgery (CAS) and intraoperative navigation (ION) can be very helpful in complex midface resections. The main objective of this paper is to evaluate if the ION could improve the rate of free surgical margins in locally advanced midface malignancies.

MATERIALS AND METHODS

A retrospective cohort study was performed including 40 patients with a locally advanced malignant midface tumor (T4a/b) surgically treated from September 2016 to September 2022. Patients were divided in two groups, a control group included 20 patients operated on without ION and the study group included 20 patients treated with Navigation assisted surgery. A systematic analysis was performed comparing surgical margins in both groups.

RESULTS

Squamous cell carcinoma was the most common histological type. Oral cavity was the most common primary location. Overall, considering each specimen as an hexahedrium, 240 surgical margins were analyzed. 15 out of 120 margins analyzed in the navigation group (12.5 %) were positive while 30 out of 120 margins analyzed in control group (25 %) were affected (p 0.013). Concerning margin location, the ION group showed less involvement of the upper surface of specimen than in control group (p 0.048).

CONCLUSION

Navigation Assisted Surgery seems to improve the rate of free surgical margins in patients with locally advanced midface malignancies, specially concerning involvement of the superior margin. Further studies are recommended to corroborate these results and its potential influence in survival rates.

Virtual Surgical Planning in Head and Neck Reconstruction

Virtual surgical planning is a revolutionary tool for the head and neck reconstructive surgeon. As with any tool, there are strengths and weaknesses. The strengths include shorter operative time, shorter ischemic time, streamlined dental rehabilitation, facilitation of complex reconstruction, non-inferior and possibly superior accuracy, and increased durability. The weaknesses are increased up-front costs, potential delays to operative management, limited flexibility on the day of surgery, and loss of familiarity with conventionally planned surgery.

The Cost Utility of Virtual Surgical Planning and Computer-Assisted Design/Computer-Assisted Manufacturing in Mandible Reconstruction Using the Free Fibula Osteocutaneous Flap

BACKGROUND

 The use of virtual surgical planning and computer-assisted design and computer-assisted manufacturing (CAD/CAM) has become widespread for mandible reconstruction with the free fibula flap. However, the cost utility of this technology remains unknown.

METHODS

 The authors used a decision tree model to evaluate the cost utility, from the perspective of a hospital or insurer, of mandible reconstruction using CAD/CAM relative to the conventional (non-CAD/CAM) technique for the free fibula flap. Health state probabilities were obtained from a published meta-analysis. Costs were estimated using 2018 Centers for Medicare and Medicaid Services data. Overall expected cost and quality-adjusted life-years (QALYs) were assessed using a Monte Carlo simulation and sensitivity analyses. Cost effectiveness was defined as an incremental cost utility ratio (ICUR) less than the empirically accepted willingness-to-pay value of $50,000 per QALY.

RESULTS

 Although CAD/CAM reconstruction had a higher expected cost compared with the conventional technique ($36,487 vs. $26,086), the expected QALYs were higher (17.25 vs. 16.93), resulting in an ICUR = $32,503/QALY; therefore, the use of CAD/CAM in free fibula flap mandible reconstruction was cost-effective relative to conventional technique. Monte Carlo sensitivity analysis confirmed CAD/CAM's superior cost utility, demonstrating that it was the preferred and more cost-effective option in the majority of simulations. Sensitivity analyses also illustrated that CAD/CAM remains cost effective at an amount less than $42,903 or flap loss rate less than 4.5%.

CONCLUSION

 This cost utility analysis suggests that mandible reconstruction with the free fibula osteocutaneous flap using CAD/CAM is more cost effective than the conventional technique.

Role of 3D Printing in Post-op Rehabilitation of Palatal Bone Loss by Mucormycosis: A Survey

BACKGROUND

Three dimensions (3D) modeling, printing, and manufacturing can help in personalized and customized surgical reconstruction of complex defects in the craniofacial region with precision by manipulating tissues based on the preoperative assessment, planning the shape of metal and alloplastic materials, and reduction in the total cost and time of the surgery.

AIM

The present survey study aimed to assess the approach of treating surgeons towards the role of 3D printing in post-op rehabilitation of palatal bone loss by mucormycosis.

METHODS

One thousand eyes nose and throat (ENT) and maxillofacial surgeons were given a pre-formed structured survey questionnaire to be filled by subjects themselves for their view on the role of 3D printing for rehabilitation and reconstruction of palatal bone loss due to mucormycosis.

RESULTS

Efficacy of 3D printing to print the pneumatic sinus design and palatal contour helping to design accurate support with a lightweight prosthesis, 67.2% (n=672) subjects whereas, exact duplication of the excised tissue, 85.4% (n=854) subjects, to detect and duplicate undercuts, 58.4% (n=584) subjects, 3D printing can be helpful as the proper extension of impression 73.2% (n=732) subjects responded positively. For reconstruction of a lost palate by prosthesis 91.2% (n=912) of study participants, in making obturators using Titanium framework and Polyetheretherketone (PEEK) was given a positive response by 82.2% (n=822) subjects, to fabricate prosthesis obturator required in palatal perforation in case of mucormycosis was given a positive response by 88.1% (n=881) subjects, the role of 3D printing to overlay zygomatic implant prosthesis was responded positively by 68.9% (n=689) study subjects.

CONCLUSION

The present survey study concludes that 3D printing is a reliable and accurate method for palatal reconstruction following bone destruction by mucormycosis as reported by the majority of ENT and maxillofacial surgeons.

Virtual planning and 3D-printed guides for mandibular reconstruction: Factors impacting accuracy

Objectives

Examine accuracy and factors impacting accuracy for mandibular reconstruction with virtual surgical planning, 3D printed osteotomy guides and preoperatively bent mandibular reconstruction plate (VSP/3Dprinted-guide/plate).

Method

Retrospective review of osseous-free-flap mandibular reconstructions with VSP/3Dprinted-guide/plate between January 2015 and July 2020 at a single academic medical center.Patient demographics, disease, and treatment variables were extracted. Accuracy was assessed by 3D-model-overlay with cephalometric and donor-bone segment length measurements. Multivariate analyses were performed to determine factors impacting cephalometric accuracy.

Results

60 cases met criteria: 41 (68%) cancer, 14 (23%) osteoradionecrosis (ORN), 5 (8%) secondary mandibular reconstruction. Thirteen cases (22%) were Brown class III or IV. Thirty-nine cases (65%) had ≥2 flap bone segments. Average donor-bone length was 82 mm (SD: 28). 3D-model-overlay accuracy demonstrated minimal deviation between planned and actual reconstruction: intercondylar distance = 2.10 mm (SD: 2.2); intergonial distance = 2.23 mm (SD: 1.9); anterior-posterior distance (APD) = 1.76 mm (SD: 1.5); gonial angle (GA) = 3.11 degrees (SD: 2.4). Mean change in donor-bone segment length inferiorly was 2.67 mm (SD: 2.6) and superiorly 3.27 mm (SD: 3.2). Higher number of donor-bone segments was associated with decreased accuracy in GA (p = .023) and longer donor-bone length was associated with decreased accuracy in APD (p = .031).

Conclusion

To our knowledge this is the largest series assessing surgical accuracy of VSP/3Dprinted-guide/plate for osseous-free-flap mandibular reconstruction. We demonstrate highly accurate results, with increased number of donor-bone segments and donor-bone length associated with decreased accuracy. Our findings further support VSP/3Dprinted-guide/plate as a reliable and accurate tool for mandibular reconstruction.

Level of Evidence

Level 4.

Influence of Radiotherapy on Ossification of Vascularized Osseous Reconstruction of the Jaw: A Radiological Retrospective Cohort Study Based on Panoramic Radiographs

Background: The aim of this study was to evaluate the impact of irradiation and time of irradiation on the ossification of jaws reconstructed with free bone grafts. Methods: In total, 100 reconstructions of the jaw were retrospectively evaluated for ossification between bone segments by two raters based on postoperative panoramic radiographs (immediate postOP, approximately 6, 12 and 24 months follow-up). Three subgroups were divided according to the time of irradiation: preoperative radiation therapy (n = 41), postoperative radiation therapy (n = 26) and patients without any radiation therapy (n = 33) as the control group. Ossification time and influencing factors were documented. Results: The fastest ossification with a median of 304 ± 37 days was observed (p < 0.001) in the nonirradiated control group. No significant difference (p = 0.087) in ossification was found between the pre- (447 ± 136 days) and postoperative (510 ± 112 days) radiation groups. Ossification between two graft segments (336 ± 38 days) showed significantly (p < 0.001) faster ossification than between the original and grafted bone (448 ± 85 days). Moreover, closer initial contact between the segments resulted in faster ossification (p < 0.001). When analyzing cofactors, tobacco consumption was the only negative factor aggravating ossification (p = 0.006). Conclusion: Head and neck radiation corresponded with the impaired and prolonged ossification of jaw reconstructions with free bone grafts. There was no difference in ossification if radiotherapy was performed before or after reconstructive surgery. A close bony contact was particularly important for ossification between the original and grafted bone.

Comparison of augmented reality and cutting guide technology in assisted harvesting of iliac crest grafts - A cadaver study

BACKGROUND

Harvesting vascularized bone grafts with computer-assisted surgery represents the gold standard for mandibular reconstruction. However, current augmented reality (AR) approaches are limited to invasive marker fixation. This trial compared a markerless AR-guided real-time navigation with virtually planned and 3D printed cutting guides for harvesting iliac crest grafts.

MATERIAL AND METHODS

Two commonly used iliac crest transplant configurations were virtually planned on 10 cadaver hips. Transplant harvest was performed with AR guidance and cutting guide technology. The harvested transplants were digitalized using cone beam CT. Deviations of angulation, distance and volume between the executed and planned osteotomies were measured.

RESULTS

Both AR and cutting guides accurately rendered the virtually planned transplant volume. However, the cumulative osteotomy plane angulation differed significantly (p = 0.018) between AR (14.99 ± 11.69°) and the cutting guides (8.49 ± 5.42°). The cumulative osteotomy plane distance showed that AR-guided navigation had lower accuracy (2.65 ± 3.32 mm) than the cutting guides (1.47 ± 1.36 mm), although without significant difference.

CONCLUSION

This study demonstrated the clinical usability of markerless AR-guided navigation for harvesting iliac crest grafts. Further improvement of accuracy rates might bring clinical implementation closer to reality.

Precision of Low-Cost Augmented Reality in Prefabricated Cutting Guide for Fibular Free Flap Surgery

BACKGROUND

Augmented reality (AR) is an imaging technology encompassing an interactive experience of a real-world environment enhanced by computer-generated perceptual information. It has been introduced to current medical practice to help the preoperative planning in many surgical fields.

METHODS

The authors applied AR to the computed tomography angiography of 8 patient's legs. Computed tomography angiography images were processed into Digital Imaging and Communications in Medicine files to make a prefabricated cutting guide and customized titanium plate. Also, three-dimensional reconstruction of the arterial supply of the leg was performed to identify the perforators.

RESULTS

Followed by preoperative marking of operative details on patient's skins in antero-posterior view, lateral view, and combination of both views. Inaccuracy of measurement was confirmed by duplex ultrasound which average error of the combination of antero-posterior and lateral viewed of both legs was lowest (0.7 ± 0.2 cm). Followed by lateral view (1.0 ± 0.3 cm) and antero-posterior view (1.2 ± 0.4 cm), respectively.

CONCLUSIONS

Augmented reality can improve patient's safety by directly locate the perforator and easily to design the skin paddle. Followed by satisfaction and confidence in patients and their relatives. Augmented reality also promoted understanding of operative steps for related assistants, residents, or fellows. Augmented reality can perform with existing equipment, mobile phone application, and can save the cost for preoperative planning. Distortion in the depth view can be more accurate by combining of AR in antero-posterior and lateral view.

Navigation of iliac crest graft harvest using markerless augmented reality and cutting guide technology: A pilot study

BACKGROUND

Defects of the facial skeleton often require complex reconstruction with vascularized grafts. This trial elucidated the usability, visual perception and accuracy of a markerless augmented reality (AR)-guided navigation for harvesting iliac crest transplants.

METHODS

Random CT scans were used to virtually plan two common transplant configurations on 10 iliac crest models, each printed four times. The transplants were harvested using projected AR and cutting guides. The duration and accuracies of the angulation, distance and volume between the planned and executed osteotomies were measured.

RESULTS

AR was characterized by the efficient use of time and accurate rendition of preoperatively planned geometries. However, vertical osteotomies and complex anatomical settings displayed significant inferiority of AR guidance compared to cutting guides.

CONCLUSIONS

This study demonstrated the usability of a markerless AR setup for harvesting iliac crest transplants. The visual perception and accuracy of the AR-guided osteotomies constituted remaining weaknesses against cutting guide technology.

Adherence to Computer-Assisted Surgical Planning in 136 Maxillofacial Reconstructions

Objective

To investigate the adherence to initially planned maxillofacial reconstructions using computer-assisted surgery (CAS) and to identify the influential factors affecting its compliance for maxillofacial reconstruction.

Patients and Methods

A retrospective analysis of 136 computer-assisted maxillofacial reconstructive surgeries was conducted from January 2014 to June 2020. The categorical parameters involved age, gender, disease etiology, disease site, defect size, bone flap segments, and flap type. Apart from descriptive data reporting, categorical data were related by applying the Fisher-exact test, and a p-value below 5% was considered statistically significant (P < 0.05).

Results

The main reasons for partial or non-adherence included unfitness, patient health condition, and other subjective reasons. Out of the total patient population, 118 patients who underwent mandibular reconstruction showed higher CAS compliance (83.9%) compared to the 18 midface reconstruction (72.2%) without any statistically significant difference (p = 0.361). Based on the size of the defect, a significantly higher CAS compliance (p = 0.031) was observed with a minor defect (80.6%) compared to the large-sized ones (74.1%). The bone flaps with two or more segments were significantly (p = 0.003) prone to observe a partial (15.4%) or complete (12.8%) discard of the planned CAS compared to the bone flaps with less than two segments. The malignant tumors showed the lowest CAS compliance when compared to other disorders without any significant difference (p = 0.1).

Conclusion

The maxillofacial reconstructive surgical procedures offered optimal compliance to the initially planned CAS. However, large-sized defects and multiple bone flap segments demonstrated a higher risk of partial or complete abandonment of the CAS.

Advanced Three-Dimensional Technologies in Craniofacial Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the evolution of three-dimensional computer-aided reconstruction and its current applications in craniofacial surgery. 2. Recapitulate virtual surgical planning, or computer-assisted surgical simulation, workflow in craniofacial surgery. 3. Summarize the principles of computer-aided design techniques, such as mirror-imaging and postoperative verification of results. 4. Report the capabilities of computer-aided manufacturing, such as rapid prototyping of three-dimensional models and patient-specific custom implants. 5. Evaluate the advantages and disadvantages of using three-dimensional technology in craniofacial surgery. 6. Critique evidence on advanced three-dimensional technology in craniofacial surgery and identify opportunities for future investigation.

SUMMARY

Increasingly used in craniofacial surgery, virtual surgical planning is applied to analyze and simulate surgical interventions. Computer-aided design and manufacturing generates models, cutting guides, and custom implants for use in craniofacial surgery. Three-dimensional computer-aided reconstruction may improve results, increase safety, enhance efficiency, augment surgical education, and aid surgeons' ability to execute complex craniofacial operations. Subtopics include image analysis, surgical planning, virtual simulation, custom guides, model or implant generation, and verification of results. Clinical settings for the use of modern three-dimensional technologies include acquired and congenital conditions in both the acute and the elective settings. The aim of these techniques is to achieve superior functional and aesthetic outcomes compared to conventional surgery. Surgeons should understand this evolving technology, its indications, limitations, and future direction to use it optimally for patient care. This article summarizes advanced three-dimensional techniques in craniofacial surgery with cases highlighting clinical concepts.

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.

Comparison of surgical outcomes between primary plate and fibular flap transfer for reconstruction of segmental mandibular defects

PURPOSE

Although two ways of reconstruction have been reviewed for a long period, comparison of large sample size with nearly randomized patient selection is rare. Here, we compare the surgical outcomes of these two methods from two large medical institutes.

METHODS

Totally 176 patients were included from two medical centers with different protocols, 62 patients from MacKay Hospital repair defects with fibula flaps using reconstruction plates. Also 114 patients from Kaohsiung ChangGung Hospital treat with reconstruction plates combine anterior lateral thigh flaps, in which 12 cases had secondary fibula flap after plate exposure. Electronic medical records were reviewed retrospectively. Short (3-12 months) and long-term (>12 months) outcomes were evaluated.

RESULTS

Short-term evaluation revealed that the secondary fibula had a higher rate of vascular complications (33 vs. 6%, p = .02). Primary fibula had a higher risk of post reconstructive surgical debridement (60 vs. 40%, p = .018). Long-term follow-up revealed radiation therapy significantly worsened bone healing (p = .03). Primary fibula had a lower rate of screw loosening (14.0 vs. 40.3%, p = .002). Radiation therapy did not increase the plate exposure rate among the groups (33 vs. 27%, p = .389). Disease free survival showed no significant difference between two groups (53.1 ± 3.5 vs. 47.8 ± 2.8 months, p = .317).

CONCLUSION

Primary fibula reconstruction should be considered whenever possible to reduce the risk of late complications and simplifies the management after a potential plate exposure. Notably, radiation therapy apparently has no significant effect on plate exposure rate both in ALT or fibula groups.

Dental 3D-Printing: Transferring Art from the Laboratories to the Clinics

The rise of three-dimensional (3D) printing technology has changed the face of dentistry over the past decade. 3D printing is a versatile technique that allows the fabrication of fully automated, tailor-made treatment plans, thereby delivering personalized dental devices and aids to the patients. It is highly efficient, reproducible, and provides fast and accurate results in an affordable manner. With persistent efforts among dentists for refining their practice, dental clinics are now acclimatizing from conventional treatment methods to a fully digital workflow to treat their patients. Apart from its clinical success, 3D printing techniques are now employed in developing haptic simulators, precise models for dental education, including patient awareness. In this narrative review, we discuss the evolution and current trends in 3D printing applications among various areas of dentistry. We aim to focus on the process of the digital workflow used in the clinical diagnosis of different dental conditions and how they are transferred from laboratories to clinics. A brief outlook on the most recent manufacturing methods of 3D printed objects and their current and future implications are also discussed.

Three-dimensional (3D) synthetic printing for the manufacture of non-biodegradable models, tools and implants used in surgery: a review of current methods

The advent of three-dimensional (3D) printing in the 1980s ushered in a new era of manufacturing. Original 3D printers were large, expensive and difficult to operate, but recent advances in 3D printer technologies have drastically increased the accessibility of these machines such that individual surgical departments can now afford their own 3D printers. As adoption of 3D printing technology has increased within the medical industry so too has the number of 3D printable materials. Selection of the appropriate printer and material for a given application can be a daunting task for any clinician. This review seeks to describe the benefits and drawbacks of different 3D printing technologies and the materials used therein. Commercially available printers using fused deposition modelling or fused filament fabrication technology and relatively inexpensive thermoplastic materials have enabled rapid manufacture of anatomic models and intraoperative tools as well as implant prototyping. Titanium alloys remain the gold-standard material for various implants used in the fixation of craniofacial or extremity fractures, but polymers and ceramics are showing increasing promise for these types of applications. An understanding of these materials and their compatibility with various 3D printers is essential for application of this technology in a healthcare setting.

Contemporary Approach to Locally Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Surgical management of locally advanced oral cavity squamous cell carcinomas (OCSCC) has long been recognized as a primary treatment modality. Technological advances have led to significant improvements in our surgical approach, from improvement in the visualization of tumors to more efficient and precise reconstruction. Here, we review the latest technological advances in surgical extirpation and reconstruction of locally advanced OCSCCs.

RECENT FINDINGS

The focus of technological innovation in surgical extirpation has been on improving visualization, with the use of intraoperative ultrasound for margin delineation, intraoperative navigation, narrow-band imaging, and the use of fluorescence. Though early, these are promising steps to ensuring complete resection of the cancer. Advances in reconstruction have been centered on the incorporation of computer assisted design, manufacturing, and virtual surgical planning, allowing for more complex three-dimensional defects to be expeditiously reconstructed. As these technologies are still under development, their impact on oncologic outcomes are not yet robustly defined; however, as technology continues to advance and become more widely available, new technologies will undoubtedly become integrated into enhancing surgical precision and planning.

Matching locating holes in multiple plates to record bone position for accurate reconstruction after segmental mandibulectomy

Segmental defect areas in the mandible can change immediately following osteotomy due to muscular traction, impacting on accurate reconstruction. The purpose of this article is to introduce a new technique based on virtual surgery planning to record the position of the bony parts prior to mandibulectomy, for use in precise mandibular reconstruction after segmental osteotomy. The position information for the bony parts is transferred to a plate with complementary surface contact and locating holes with specific directions and angles. This technique was performed for six patients with segmental defects and the results were compared to those of six previous patients in whom the technique was not utilized. The design of the location holes shortened the average operation time from 406 minutes to 349 minutes (P = 0.033) and decreased the average, maximum, and minimum graft deviation from 1.21 mm to 0.88 mm (P = 0.015), 1.28 mm to 0.99 mm (P = 0.027), and -1.15 mm to -0.77 mm (P = 0.077), respectively. The design of the locating holes in multiple plates shortened the time taken for the bony repositioning step and hence significantly shortened the total operation time. More importantly, it also increased the reconstructive accuracy.