Long-term stability of jaw reconstruction with microvascular bone flaps: A prospective longitudinal study.

OBJECTIVES: Microvascular bone flap jaw reconstruction has achieved satisfactory clinical outcomes. However, little is known about the long-term stability of the reconstructed jaw. This prospective longitudinal study aimed to investigate the long-term stability of jaw reconstruction and factors that were associated with it. METHODS: Patients with successful computer-assisted osseous free-flap jaw reconstruction in the Department of Oral and Maxillofacial Surgery, Queen Mary Hospital, Hong Kong were recruited for this prospective longitudinal study. The three-dimensional jaw models at the pre-operative plan, post-operative 1-month, and 2 years were aligned and compared. RESULTS: A total of 69 patients were recruited, among which 48 patients were available for the long-term analysis. Compared to 1-month after surgery, further deviation from the pre-operative plan was observed at post-operative 2 years. Lack of accuracy in surgery, segmental mandible resection especially with the involvement of mandible angles, and post-operative radiation therapy were identified as the significant factors affecting the positional stability of the reconstructed jaw (p < 0.05). Stable reconstruction was observed in the subgroup analysis of patients without post-operative radiation therapy. CONCLUSION: Up to the best of our knowledge, this is the first prospective longitudinal study reporting the long-term stability of jaw reconstruction and its affecting factors. Our data demonstrated that the reconstructed jaw position lacked stability over the postoperative period. How to improve long-term stability of reconstructed jaw thus optimize the functional outcomes warrants further studies.

A quantitative comparison of bone resection margin distances in virtual surgical planning versus histopathology: a prospective study.

BACKGROUND: Positive bone margins have been shown to be associated with worse locoregional control and survival performance in oral oncology patients. With the application of computer-assisted surgery and patient-specific surgical guides, the authors can accurately execute the preoperative osteotomy plan. However, how well the authors can predict the margin distance in the final histopathology with a preoperative computed tomography (CT) scan, the factors associated with it, and how much leeway CT should spare when designing the osteotomy planes during virtual surgical planning (VSP) remain to be investigated. MATERIALS AND METHODS: Patients from January 2021 to December 2022 with benign or malignant jaw tumors and with signs of bone marrow involvement in the preoperative CT scan in our center were prospectively recruited to the study. VSP and measurement of the closest margin distance in the CT scan were performed by the single team of surgeons. The resection specimen was processed, and the margin distances were measured by a dedicated senior pathologist with the knowledge of orientation of the osteotomy planes. RESULTS: A total of 35 patients were recruited, with 21 malignant and 14 benign cases. Sixty-eight bone margins were quantitatively analyzed. No significant difference in margin distances measured from the CT scan and final histopathology was detected ( P =0.19), and there was a strong correlation between the two (r s =0.74, P <0.01). A considerable amount of variance was detected in the level of discrepancy between margin distances measured in the CT scan and final histopathology (overall SD=6.26 mm, malignancy SD=7.44 mm, benign SD=4.40 mm). No significant correlation existed between the two margin distances when only maxilla tumor margins were assessed ( P =0.16). CONCLUSION: The bone margin distance in VSP is reliably correlated to the final pathological margin distance. A leeway distance of 15mm and 9mm should be considered when designing the osteotomy planes for malignancy and benign cases, respectively. Extra attention should be paid to maxilla cases when predetermining the osteotomy planes during VSP.

Platinum-based chemotherapy induces demyelination of Schwann cells in oral squamous cell carcinoma treatment.

BACKGROUND: Cisplatin, carboplatin, and oxaliplatin are the only three platinum-based antineoplastic drugs that have been accepted worldwide for treating various cancers. Up to 83.6% of patients treated with platinum-based antineoplastic drugs will develop chemotherapy-induced peripheral neuropathy (CIPN), manifesting as sensory paresthesias, dysesthesias, and hypoesthesias that can cause significant adverse impact to daily activities. AIM: To investigate how these three platinum-based drugs affect mitochondrial function and myelination state of Schwann cells and the signalling pathway involved. METHOD: 2 µM Cisplatin, 20 µM carboplatin, and 1 µM oxaliplatin were used to inhibit the growth of CAL-27 by 20% respectively. These drugs were then used to induce chemotherapy-induced peripheral neuropathy in Rat Schwann Cells (RSC96). The changes in cell metabolism and myelin formation in RSC96 were investigated. RESULT: Cisplatin and carboplatin, but not oxaliplatin increased intracellular and mitochondrial reactive oxygen species in RSC96. Only Cisplatin and carboplatin decreased mitochondrial membrane potential (ΔΨm) and ATP production in RSC96. Both Cisplatin and carboplatin led to demyelination of RSC96, characterized by increased expression of p75NTR and decreased expression of myelin protein zero (MPZ). CONCLUSION: Cisplatin and carboplatin, but not oxaliplatin, caused mitochondrial dysfunction and induced demyelination in RSC96 while showing similar toxicity to head and neck cancer cells. Oxaliplatin may be a potential chemotherapy drug to prevent CIPN in patients with head and neck cancer.

Melatonin and erastin emerge synergistic anti-tumor effects on oral squamous cell carcinoma by inducing apoptosis, ferroptosis, and inhibiting autophagy through promoting ROS.

BACKGROUND: Oral squamous cell carcinomas are one of the most common cancers worldwide with aggressive behavior and poor prognosis. Reactive oxygen species (ROS) are associated with cancer and cause various types of regulated cell death (RCD). Inducing the RCD pathway by modulating ROS levels is imperative to conquer cancers. The aim of this study is to investigate the synergistic anticancer effects of melatonin and erastin on ROS modulation and subsequent RCD induction. METHODS: Human tongue squamous cell carcinoma cell lines (SCC-15 cells) were treated with melatonin, erastin, or their combination. Cell viability, ROS levels, autophagy, apoptosis, and ferroptosis levels were tested according to the results of the PCR array, which were verified with/without the induction and inhibition of ROS by H2O2 and N-acetyl-L-cysteine, respectively. In addition, a mouse-based subcutaneous oral cancer xenograft model was constructed to identify the effects of melatonin, erastin, and their combination on the autophagy, apoptosis, and ferroptosis levels in isolated tumor tissues. RESULTS: ROS levels were increased by the administration of melatonin at high concentrations (mM), and the combination of melatonin with erastin enhanced the levels of malonic dialdehyde, ROS, and lipid ROS, and reduced the levels of glutamate and glutathione. SQSTM1/p62, LC3A/B, cleaved caspase-3, and PARP1 protein levels in SCC-15 cells were also increased by melatonin plus erastin treatment, which further increased as ROS accumulated, and decreased as ROS levels were suppressed. Combined treatment of melatonin and erastin markedly reduced the tumor size in vivo, demonstrated no obvious systemic side effects, and significantly enhanced the apoptosis and ferroptosis levels in the tumor tissues, in parallel with decreased autophagy levels. CONCLUSIONS: Melatonin combined with erastin exhibits synergistic anticancer effects without adverse reactions. Herein, this combination might become a promising alternative strategy for oral cancer treatment.

Tumor-associated macrophages facilitate oral squamous cell carcinomas migration and invasion by MIF/NLRP3/IL-1ß circuit: A crosstalk interrupted by melatonin.

Invasion and migration are significant challenges for treatment of oral squamous cell carcinomas (OSCCs). Tumor-associated macrophages (TAMs) interact with cancer cells and are involved in tumor progression. Our recent study demonstrated that melatonin inhibits OSCC invasion and migration; however, the mechanism by which melatonin influences crosstalk between TAMs and OSCCs is poorly understood. In this study, a co-culture system was established to explore the interactions between human monocytic cells (THP-1 cells) and human tongue squamous cell carcinoma cells (SCC-15 cells). The results were verified using monocyte-derived macrophages (MDMs) isolated and differentiated from primary peripheral blood mononuclear cells. In vivo, assays were performed to confirm the anticancer effects of melatonin. SCC-15 cells co-cultured with THP-1 cells or MDMs exhibited increased migration and invasion, which was reversed by melatonin. Co-culture also increased the expression of macrophage migration inhibitory factor (MIF), CD40, CD163 and IL-1ß, and these changes were also reversed by melatonin. Moreover, IL-1ß secretion in THP-1 cells was MIF- and NLR family pyrin domain-containing 3 (NLRP3)-dependent, and treated with IL-1ß enhanced the invasion and migration of SCC-15 cells. Furthermore, melatonin treatment significantly decreased tumor volumes and weights, and tumors from mice treated with melatonin had lower levels of MIF, NLRP3, and IL-1ß than tumor from control mice. These results demonstrate that macrophages facilitate the progression of OSCCs by promoting the MIF/NLRP3/IL-1ß signaling axis, which can be interrupted by melatonin. Therefore, melatonin could act as an alternative anticancer agent for OSCCs by targeting this signaling axis.

Use of Melatonin in Cancer Treatment: Where Are We?

Cancer represents a large group of diseases accounting for nearly 10 million deaths each year. Various treatment strategies, including surgical resection combined with chemotherapy, radiotherapy, and immunotherapy, have been applied for cancer treatment. However, the outcomes remain largely unsatisfying. Melatonin, as an endogenous hormone, is associated with the circadian rhythm moderation. Many physiological functions of melatonin besides sleep-wake cycle control have been identified, such as antioxidant, immunomodulation, and anti-inflammation. In recent years, an increasing number of studies have described the anticancer effects of melatonin. This has drawn our attention to the potential usage of melatonin for cancer treatment in the clinical setting, although huge obstacles still exist before its wide clinical administration is accepted. The exact mechanisms behind its anticancer effects remain unclear, and the specific characters impede its in vivo investigation. In this review, we will summarize the latest advances in melatonin studies, including its chemical properties, the possible mechanisms for its anticancer effects, and the ongoing clinical trials. Importantly, challenges for the clinical application of melatonin will be discussed, accompanied with our perspectives on its future development. Finally, obstacles and perspectives of using melatonin for cancer treatment will be proposed. The present article will provide a comprehensive foundation for applying melatonin as a preventive and therapeutic agent for cancer treatment.

A Comprehensive Approach for Measuring Spatial Deviations of Computer-Assisted Mandibular Reconstruction.

BACKGROUND: Computer-assisted surgery has become the mainstream in mandibular reconstruction, but the lack of a standard measuring approach for spatial deviations of mandible hinders postoperative verification and the comparison of different subjects. This study aims to set up a comprehensive approach for measuring spatial deviations of computer-assisted mandibular reconstruction. METHODS: A systematic review was conducted to extract all measurements for computer-assisted mandibular reconstruction. Thereafter, eligible measurements were included in the authors' comprehensive approach, which categorized the measurements according to different anatomical structures and landmarks. RESULTS: A total of 80 studies were included in the authors' systematic review, and 31 measurements were extracted. The authors established a comprehensive panel of anatomical landmarks to facilitate measurement, including parts, points, lines, planes, and angles. These measurements encompassed spatial deviations of the overall mandible, condyle, gonial angle, bone grafts, midline, surgical plate, osteotomy, and miscellaneous indicators. A calculation spreadsheet was developed to collect landmarks and compute deviations automatically with built-in formulas. Finally, a simplified panel of measurements was recommended for spatial deviations of mandibular reconstruction. CONCLUSIONS: A comprehensive approach for measuring spatial deviations of computer-assisted mandibular reconstruction was established. Future studies will confirm this approach as an effective and scientific system for postoperative verification of computer-assisted mandibular reconstruction.

Unexpected Change of Surgical Plans and Contingency Strategies in Computer-Assisted Free Flap Jaw Reconstruction: Lessons Learned From 98 Consecutive Cases.

BACKGROUND: Computer-assisted surgeries (CAS) are increasingly being adopted as the treatment of choice for jaw reconstructions with osseous free flaps. Although unexpected change of surgical plans remains a major concern of CAS, there are few studies focusing on this unfavorable clinical scenario. The aim of the present study was to investigate the rate of unexpected change of surgical plans and potential influential parameters, and to discuss the contingency strategies. METHODS: A retrospective study was performed to evaluate all the patients who underwent computer-assisted jaw resections and osseous free flap reconstructions. The postoperative radiographs were reviewed and compared with the preoperative surgical plans. Operating records were examined to analyze the reasons for unexpected change of surgical plans and the management. The potential influential parameters for the change of surgical plans were analyzed using Fisher-exact test. The difference was regarded as statistically significant for a p-value less than 5%. RESULTS: From Nov 2014 to Oct 2021, a total of 98 consecutive computer-assisted free flap jaw reconstruction cases with osseous free flaps were included in this study. Our experience showed that 5.1% of the patients (five cases) needed intra-operative change of the surgical plans. We summarized the unexpected change of surgical plans and the contingency strategies as four clinical scenarios, including extended resection and reconstruction, shortened resection and reconstruction, modified resection without changing reconstruction, and modified reconstruction without changed resection. None of the potential influential parameters was identified as significant in relation to unexpected change of surgical plans intraoperatively. CONCLUSION: Our experience shows that with the comprehensive methodology for computer-assisted free flap jaw reconstruction surgery planning, we can minimize the possibility of unexpected change of surgical plans during surgery. The lessons learned from our 98 consecutive cases can help beginners prevent unexpected change of surgical plans and rationalize contingency strategies in computer-assisted free flap jaw reconstruction.

The Learning Curve of Computer-Assisted Free Flap Jaw Reconstruction Surgery Using 3D-Printed Patient-Specific Plates: A Cumulative Sum Analysis.

BACKGROUND: Computer-assisted jaw reconstruction (CAJR) has benefits in reducing operation time and improving reconstruction accuracy, compared to conventional freehand jaw reconstruction. However, no information is available regarding learning curves in CAJR with the use of 3D-printed patient-specific surgical plates (PSSP). The purpose of this study was to assess surgical outcomes and learning curve for the first 58 consecutive CAJR using 3D-printed PSSP performed by a single surgical team in a single institution. METHODS: In a prospective study, consecutive patients who underwent free flap CAJR using 3D-printed PSSP were included. The determination of proficiency, based on the cumulative sum of surgical success (no major adjustment of 3D-printed PSSP, flap survival) passing the acceptable boundary line of cumulative sum analysis, was the primary outcome. To find out any potential factors influencing the learning curve, baseline characteristics of patients were compared before and after proficiency achievement. Secondary outcomes included inflexion points of the total operation time, blood loss, length of hospital stay, and bone graft deviation, measured by the cumulative sum analysis. RESULTS: From December 2016 to November 2020, 58 consecutive cases underwent surgery performed by a single surgical team. The overall surgical success rate was 94.8% (55/58). A three-stage learning curve of primary outcome was observed. The proficiency was achieved after 23 cases. The proportions of advanced tumor staging and concomitant surgery after obtaining proficiency were significantly higher than those before achieving proficiency (p = 0.046 and p < 0.001, respectively). Mean values of operation time, intraoperative blood loss, length of hospital stay, and bone graft deviation were 532.5 ± 119.2 min, 1,006.8 ± 547.2 ml, 16.1 ± 6.3 days, and 0.9 ± 1.2 mm, respectively. Two trends of learning curve were observed in the CUSUM analyses of total operation time, length of hospital stay, and bone graft deviation, in which the first and second inflexion points occurred between 8 and 17 cases and between 43 and 46 cases, respectively. CONCLUSION: Our results revealed a three-stage learning curve of CAJR with the use of PSSP, including initial learning, plateau, and overlearning. Based on CUSUM analysis, the surgical proficiency was achieved after 23 cases, and total operation time, length of hospital stay, and bone graft deviation stabilized after 8-17 cases.

Melatonin Suppresses Oral Squamous Cell Carcinomas Migration and Invasion through Blocking FGF19/FGFR 4 Signaling Pathway.

Oral squamous cell carcinomas (OSCCs) are one of the most prevalent malignancies, with a low five-year survival rate, thus warranting more effective drugs or therapy to improve treatment outcomes. Melatonin has been demonstrated to exhibit oncostatic effects. In this study, we explored the anti-cancer effects of melatonin on OSCCs and the underlying mechanisms. A human tongue squamous cell carcinoma cell line (SCC-15) was treated with 2 mM melatonin, followed by transwell migration and invasion assays. Relative expression levels of Fibroblast Growth Factor 19 (FGF19) was identified by Cytokine Array and further verified by qPCR and Western blot. Overexpression and downregulation of FGF19 were obtained by adding exogenous hFGF19 and FGF19 shRNA lentivirus, respectively. Invasion and migration abilities of SCC-15 cells were suppressed by melatonin, in parallel with the decreased FGF19/FGFR4 expression level. Exogenous hFGF19 eliminated the inhibitory effects of melatonin on SCC-15 cells invasion and migration, while FGF19 knocking-down showed similar inhibitory activities with melatonin. This study proves that melatonin suppresses SCC-15 cells invasion and migration through blocking the FGF19/FGFR4 pathway, which enriches our knowledge on the anticancer effects of melatonin. Blocking the FGF19/FGFR4 pathway by melatonin could be a promising alternative for OSCCs prevention and management, which would facilitate further development of novel strategies to combat OSCCs.

Three-dimensional Printing Technology for Deep Circumflex Iliac Artery Flap: From Recipient to Donor Sites.

The deep circumflex iliac artery (DCIA) flap is one of the most commonly used vascularized free flaps for jaw reconstruction; however, its clinical application is limited by donor site complications. We aimed to describe a new technique of using 3-dimensionally (3D) printed patient-specific devices for mandibular reconstruction with DCIA flap and simultaneous dental implants, and for donor site restoration after harvesting the DCIA flap. One patient with mandible ameloblastoma underwent mandibular reconstruction using a DCIA flap with the "jaw-in-a-day" approach. The 3D-printed patient-specific devices included mandibular cutting guides, DCIA harvesting and dental implant guide, surgical plate, and iliac prosthesis. The postoperative 1-month accuracy measurement showed the mean distance deviations of the mandible, transferred bone grafts, dental implants and iliac prosthesis were 1.8 mm, 2.1 mm, 0.9 mm, and 1.2 mm, respectively. Three-dimensionally printed iliac prosthesis satisfactorily restored the contour of the iliac crest after DCIA flap harvesting. No complication of donor site was recorded during the follow-up of 12 months. We successfully used 3D-printed patient-specific implants in both donor and recipient sites for DCIA flap jaw reconstruction. Further studies with a larger sample size and long-term follow-up are needed.

The Impact of Coronavirus Disease 2019 on the Disease Pattern of Oral and Maxillofacial Surgery Inpatients: A Comparative Study.

Objective: Oral and maxillofacial surgery (OMFS) is a high-risk specialty involving airway and aerosol-generating procedures, which is potentially of more risk in the era of coronavirus disease 2019 (COVID-19). We aimed to identify the impact of COVID-19 on the disease pattern of OMFS inpatients and surgeries under general anesthesia in a comparative study. Materials and Methods: We reviewed the admission and operating theater records of OMFS patients from Jan 1 to Aug 31 in 2020 and 2019. The total number of cases, presenting disease patterns, and proportion of essential and non-essential medical services were compared between 2020 and 2019. Results: There were 664 admissions and 356 general anesthesia surgical procedures included in this study. Both admission and surgery numbers were significantly reduced in 2020, compared with 2019 (p = 0.012 and 0.007, respectively). The proportion of malignancy cases increased significantly, whereas that of cleft lip and palate and temporomandibular disorder (TMD) decreased. There was a significant increase in the proportion of essential services compared with non-essential services in 2020 compared with 2019. Conclusion: Our results first reported the epidemiological data of the impact of COVID-19 on OMFS disease pattern in a comparative study. The change of disease pattern and caseload will have a long-term impact on OMFS patient care, education, and training during the pandemic. Our paper provides evidence for health policy makers to consider the relocation of medical resources and optimization of medical education and services.

A Comparative Study on a Novel Fibula Malleolus Cap to Increase the Accuracy of Oncologic Jaw Reconstruction.

OBJECTIVES: Although computer-assisted surgery using fibula flap has been widely applied for oncologic jaw reconstruction in recent years, the inaccurate positioning of the fibula harvest guide brings sliding and rotational errors, which leads to compromised accuracy in simultaneous implant placement and dental rehabilitation. This study aimed to develop a novel three-dimensional (3D)-printed patient-specific fibula malleolus cap to increase oncologic reconstruction accuracy. METHODS: In this prospective comparative study with a recent historical control cohort, patients in need of oncologic jaw reconstruction with fibula free flaps were recruited. In the study group, the fibula was harvested with the guide of the malleolus cap, whereas in the control group, without the malleolus cap. Deviations of location and angulation of distal fibula osteotomies, jaw reconstruction segments, and simultaneous dental implants were compared. RESULTS: Twenty patients were recruited, with 10 in each arm. The application of the malleolus cap significantly reduced the deviations in locations and angles of distal fibula osteotomies, from 9.5 to 4.1 mm and 25.3° to 8.7°. For the simultaneous dental implants placed in the fibula flaps, there was a significant increase in the accuracy of implant platform locations (the average deviation from 3.2 to 1.3 mm), apex locations (from 3.8 to 1.5 mm), and angles (from 11.3° to 4.6°). No significant difference was detected in the accuracy of fibula reconstruction segments. CONCLUSIONS: We developed a novel fibula malleolus cap to overcome the sliding and rotational errors during fibula flap harvesting for oncologic jaw reconstruction, with increased accuracy in simultaneous dental implants. This is a step forward to achieve a satisfactory functional outcome of jaw reconstruction with dental rehabilitation.

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.

"Three-in-one" patient-specific surgical guides for simultaneous dental implants in fibula flap jaw reconstruction: A prospective case series.

BACKGROUND: Conventional freehand immediate placement of dental implants is technically challenging in the jaw reconstructive surgery. Computer-aided surgery might be the best solution, however, there has not been any standard approach to ensure the accuracy and efficiency of simultaneous dental implants in fibula flap jaw reconstruction. PURPOSE: We aim to evaluate the clinical outcome of simultaneous dental implant in fibula flap using the "three-in-one" patient-specific surgical guide (3-in-1-PSSG) in an open-label, prospective, single-arm, and single-center clinical trial. MATERIALS AND METHODS: A novel computer-aided designed and three-dimensional (3D) printed 3-in-1-PSSG, which contains functions of fibula segmentation, surgical plate positioning and implant placement, was used to facilitate the reconstructive surgery and simultaneous dental implant placement. The intraoperative success of dental implant placement, implant survival rate and accuracy of dental implant placement were reported. RESULTS: From November 2018 to June 2020, 15 consecutive patients with 48 dental implants were enrolled in this study. Fifteen 3-in-1-PSSGs were fabricated with a mean number of dental implants per guide of 3.2 ± 1.5. The intraoperative success rate of this approach was 14 out of 15. With an average follow-up period of 40 weeks, the overall implant survival rate was 83.3% (40/48). Eight implants were removed due to two fibula flap failures. The mean deviation at the implant platform and implant apex were 2.8 mm (interquartile range [IQR]: 1.9-3.4) and 3.2 mm (IQR: 2.0-4.6), and the angular deviation was 2.5° (IQR: 1.1-6.8). CONCLUSIONS: Our preliminary data indicated that the 3D printed 3-in-1-PSSG facilitated simultaneous dental implant in fibula flap jaw reconstruction with a favorable intraoperative success and short-term clinical outcome. It might be a viable alternative to allow one-step immediate oral rehabilitation in patients underwent jaw reconstruction with free flaps. Long-term results with a larger sample size are warranted.

Do predetermined surgical margins compromise oncological safety in computer-assisted head and neck reconstruction?

OBJECTIVES: Computer assisted head and neck reconstruction has gained popularity over the past few years. In computer assisted surgery (CAS), surgical margins are predetermined in virtual surgery and resection guides are designed to be fitted intra-operatively. However, concerns have been raised regarding the oncological safety of predetermined surgical margins. Therefore, the aim of this study was to compare surgical margins, recurrence and survival outcomes in patients underwent CAS and non-CAS in head and neck reconstruction. METHODS: We retrospectively reviewed the patients underwent oral and maxillofacial malignancies surgical excision and free flap reconstruction from October 2014 to December 2019 by the same chief surgeon. Patients were divided into two groups depending on whether CAS and predetermined surgical margins were adopted. The primary outcome was surgical resection margin and the secondary outcomes included recurrence and survival. RESULTS: A total of 66 subjects were recruited with 37 in the CAS group and 29 in the non-CAS group. The follow-up rate was 100%. The average follow-up time was 24.5 months. No significant difference in resection margin was identified between the groups (p = 0.387). Tumor staging, margin status, perineural invasion, lymphovascular invasion and extranodal extension were identified as significant factors influencing survival. Both before and after adjustment for these prognostic factors identified, CAS and non-CAS group showed no significant difference in survival outcome. CONCLUSION: Predetermined surgical margins do not compromise oncological safety in terms of resection margin, disease recurrence and patient survival.

Lymph node ratio as prognostic variable in oral squamous cell carcinomas: Systematic review and meta-analysis.

Lymph node ratio (LNR) has been shown to be an independent prognostic factor for oral squamous cell carcinoma (OSCC) in various centre-based studies recently. A range of cut-off values have been suggested. A meta-analysis was performed to evaluate the prognostic effects of LNR and to investigate the cut-off value. Electronic search on Pubmed, Embase and Cochrane library and manual search were performed for studies up to January 2018. The outcomes were overall survival (OS), disease specific survival (DSS), disease free survival (DFS), local recurrence free survival (LF), locoregional disease free survival (LRF), and distant metastasis disease free survival (DM). 19 studies between 2009 and 2017 were included. The total number of patients was 14,254 (range 19-3958). Data was grouped into Group A (with pathological nodal disease, pN+) and Group B (with and without pathological nodal disease, pN+ and pN-). In the meta-analysis, the high LNR was significantly related to short OS (A = HR 1.902; 95%CI: 1.453-2.488, B = HR 2.76; 95%CI: 2.13-3.59), DSS (A = HR 1.728; 95%CI: 1.159-2.579; B = HR 2.83; 95%CI: 1.8-4.44) and DFS (A = HR 2.27; 95%CI: 1.74-2.96; B = HR 2.01; 95%CI: 1.44-2.82) in both groups; and shorter LRF in Group B (HR 5.013; 95%CI: 3.584-7.011). In the analysis, all cut-off values were shown to be significant and there was no strong evidence to consider a possibility of a second significant value. Based on our results, LNR is an independent prognostic factor in OSCC and may be considered in future oncologic staging systems.

A longitudinal evaluation of psychosocial changes throughout orthognathic surgery.

BACKGROUND: Jaw correction surgery can cause significant psychosocial impacts on patients. This prospective study investigated the longitudinal changes of psychosocial characteristics of patients with dentofacial deformities after jaw correction surgery and the factors that predict the psychological resilience in Hong Kong Chinese undergoing jaw correction surgery. METHODS: A longitudinal cohort study was conducted on 92 Hong Kong Chinese patients (32 males, 60 females; mean age = 24.75 ± 5.65 years), who had jaw correction surgery as treatment for their dentofacial deformities, from 1st June 2011 to 30th June 2015. Self-completed psychological inventories including Brief Symptom Inventory, Life Orientation Test, and the Adult Trait Hope Scale were used to measure distress, optimism, and hope levels respectively. Patients completed the inventories in five time points: the surgical consent signing day (usually two to three months before the surgery) (T1); one day before operation (T2), first to second post-operative week (T3), third post-operative month (T4) and sixth post-operative month (T5). RESULTS: Latent class growth analysis revealed two outcome trajectory classes: a resilience trajectory (n = 45, 48.9%) and a chronic dysfunction trajectory (n = 14, 15.2%). Another 33 (35.9%) showed erratic trajectory patterns that would not be classified into any categories. The psychological distress levels of patients in the resilience trajectory group, on average, were below the clinical threshold of the Brief Symptom Inventory at all time points. However, the opposite result was obtained for patients in the chronic dysfunctional group. Patients exhibiting a resilience trajectory pattern, when compared to those showing a chronic dysfunction pattern, had higher optimism (t(57) = 3.69, p < .0001) and hope (t(57) = 2.46, p < .05) levels at T1. Logistic regression analyses were conducted to compare the relative power of optimism and hope levels at T1 to predict resilience or chronic dysfunctional group membership. A test of the full model against a constant only model was statistically significant (χ2(2) = 24.096, p < .01). Preoperative baseline optimism (B = -.276, p < .05) but not hope (B = -.25, ns) was a significant variable to classify the outcome trajectories for psychological distress. CONCLUSIONS: Most patients were resilient to dentofacial deformities jaw correction surgery. About 15% exhibited a chronic distress pattern. An optimistic view about the surgery may enhance resilience. Pre-surgical counselling or educational sessions to facilitate a realistic positive outlook about the operation would be beneficial.

Three-dimensional printing of patient-specific surgical plates in head and neck reconstruction: A prospective pilot study.

BACKGROUND: Surgical plates have been extensively used in head and neck reconstruction and conventional plates are mass-produced with universal configurations. To overcome disadvantages of conventional surgical plates, we have been exploring patient-specific surgical plates using the three-dimensional (3D) printing technology. We hypothesized that the application of 3D-printed patient-specific surgical plates in head and neck reconstruction is feasible, safe and precise. METHODS: We are conducting a prospective clinical trial to assess the feasibility, safety and accuracy of applying 3D-printed patient-specific surgical plates in head and neck reconstruction. The primary endpoint was the intraoperative success rate. Secondary endpoints included the incidence and severity of postoperative adverse events within six months postoperatively. The accuracy of surgical outcomes was also explored by comparing the planned and final positions of the maxilla, mandible and grafted bone segments. RESULTS: From December 2016 to October 2017, ten patients were enrolled and underwent head and neck reconstruction using 3D-printed patient-specific surgical plates. The patient-specific surgical plates adapted to bone surface precisely and no plate-bending was performed. The intraoperative success rate was 100%. The average follow-up period was 6.5 months. No major adverse events were observed. The mean absolute distance deviation of integral mandible or maxilla was 1.40 ±â€¯0.63 mm, which showed a high accuracy of reconstruction. CONCLUSIONS: The 3D printing of patient-specific surgical plates could be effective in head and neck reconstruction. Surgical procedures were simplified. The precise jaw reconstruction was achieved with high accuracy. Long-term results with a larger sample size are warranted to support a final conclusion. The study protocol has been registered in ClinicalTrials.gov with a No. of NCT03057223.

Simultaneous radicular cyst and mucoepidermoid carcinoma in the maxilla: a diagnostic nightmare.

We present a case of a 20-year-old woman presenting initially with an asymptomatic palatal swelling. Radiographic examination showed a cyst at the right maxilla with bucco-lingual expansion and perforation of palatal bone. Incisional biopsy was carried out via a buccal approach and the result revealed a benign odontogenic cyst, in keeping with radicular cyst. The patient was then scheduled for cyst enucleation. During the procedure, it was found that the palatal lesion was unrelated to the maxillary cyst. Incisional biopsy of the palatal mass was carried out and revealed a low-grade mucoepidermoid carcinoma. The patient then had a partial maxillectomy with fibula flap reconstruction. There was no recurrence at postoperative 1 year follow-up and she was rehabilitated with dental implants.