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

Evaluation of dental students' learning curve in intraligamentary anesthesia using different syringe systems: A prospective crossover study

PURPOSE/OBJECTIVES

This prospective crossover preclinical trial aimed to evaluate the learning curve of dental students in successfully administering intraligamentary anesthesia (ILA) using three different syringe systems.

METHODS

Dental students performed ILA using three devices in two separate sessions, each targeting mandibular and/or maxillary premolars. The devices included two manual systems (pistol-type and lever-based) and one computer-controlled local anesthetic delivery system (CCLAD). The primary research parameter was the success rate of anesthesia, defined as the percentage of successful ILA administrations confirmed by a negative response to a cold test. Secondary parameters included pain experienced during needle penetration and injection, students' self-reported levels of mental tension and handling of the syringes, and any potential side effects.

RESULTS

A total of 110 students performed ILA on 599 teeth during the study period. When comparing the CCLAD system to the manual syringes, the CCLAD system exhibited a significantly higher overall success rate in the first session (92.5% vs. 77.4%; p < 0.001), potentially due to its precise control of anesthetic flow and pressure, which likely facilitated more effective anesthetic delivery. However, when examining the individual manual techniques, no significant difference was found between the pistol-type manual and the CCLAD system (p = 0.66). All techniques' success rate increased from the first to the second session (80.4% vs. 86.9%; p = 0.0357). Additionally, penetration pain demonstrated a significant decrease across all techniques (p < 0.01). Notably, students' anxiety levels decreased, and self-assurance increased significantly over the sessions. Undesired reversible side effects were documented in 10.9% of cases.

CONCLUSION

These findings suggest that repeated practice of ILA, particularly with different syringe systems, enhances anesthetic success and psychological readiness for patient interaction. Additional training sessions may further improve proficiency.

Perioperative anticoagulation in head and neck free flap reconstructions: Experience of an anticoagulative scheme and its modification

OBJECTIVES

Microvascular anastomoses in microvascular reconstructions induce rheological changes in the anastomosed vessels and are usually counteracted by anticoagulative medication. There is no regimen commonly agreed on. This study provides an easy to use anticoagulative regimen.

PATIENTS AND METHODS

Consecutive cases of either anticoagulative regimen between 2013 and 2018 that underwent microvascular reconstruction in the head and neck area were included in this retrospective study, resulting in 400 cases in total. Two different anticoagulative regimens were applied to 200 patients in each group: (a) intraoperatively administered unfractionated 5000 I.U. high molecular weight heparin (HMWH) and postoperatively low molecular weight heparin (LMWH, Enoxaparin) 1 mg/kg/body weight postoperatively and (b) intraoperatively LMWH 0.5 mg/kg/body weight as well as 12 h later and 1 mg/kg/body weight postoperatively.

RESULTS

The LMWH cohort showed fewer overall thromboembolic (8.5% vs. 11%; p = .40) and peripheral thrombotic events (1% vs. 3.5%; p = .18) and lung embolisms (3% vs. 4%; p = .59). The number of thromboses at the site of the anastomosis was equally distributed. In regard to flap-specific complications, LMWH was associated with a positive effect, in particular with respect to total flap losses (5% vs. 7%; p = .40) and wound-healing disorders (14.5% vs. 20%; p = .145).

CONCLUSION

Findings indicate that intra- and postoperatively administered LMWH as the only anticoagulative medication seems reliable in our clinical routine of head and neck free flap reconstructions.

Effect of segmental versus marginal mandibular resection on local and lymph node recurrences in oral squamous cell carcinoma: is tumorous bone infiltration or location and resulting soft tissue recurrences a long-term problem?

PURPOSE

Oral squamous cell carcinomas (OSCCs) adjacent to the mandible or with clinically suspected bone infiltration are surgically treated either with marginal or segmental resections. This retrospective study compared both resections regarding local recurrence and lymph node recurrence or secondary lymph node metastases.

METHODS

All consecutive primary OSCC cases between January 2007 and December 2015 that underwent mandibular marginal or segmental resection were included. Rates of local and lymph node recurrences or secondary metastases and possible risk factors such as tumor localization according to Urken's classification were recorded.

RESULTS

In total, 180 patients with 85 marginal (group I) and 95 segmental (group II) mandibular resections were analyzed. The local recurrence rates were comparable between the groups (28.2% vs. 27.4%; p = 0.897). Lymph node recurrences or secondary metastases were higher in group I (9.4% (n = 8) vs. 6.2% (n = 6); p = 0.001). Tumor localization appears to affect the outcomes. Significantly fewer local and lymph node recurrences/metastases were found for Urken's classification SB and S calculated by two-proportion z-test (p = 0.014 and 0.056, respectively). Local recurrences mostly emerged from soft tissues, which should be resected more radically than the bones.

CONCLUSION

While bone infiltration appears technically well controllable from an oncologic point of view, local recurrences and lymph node recurrences/metastases remain an issue. Regular clinical aftercare with imaging is crucial to detect recurrences.

Value of 3D printing technology combined with indocyanine green fluorescent navigation in complex laparoscopic hepatectomy

Background

Laparoscopic hepatectomy (LH) has achieved rapid progress over the last decade. However, it is still challenging to apply laparoscopy to lesions located in segments I, VII, VIII, and IVa and the hepatic hilar region due to difficulty operating around complex anatomical structures. In this study, we applied three-dimensional printing (3DP) and indocyanine green (ICG) fluorescence imaging technology to complex laparoscopic hepatectomy (CLH) to explore the effects and value of the modified procedure.

Materials and methods

From January 2019 to January 2021, 54 patients with complex hepatobiliary diseases underwent LH at our center. Clinical data were collected from these patients and retrospectively analyzed.

Results

A total of 30 patients underwent CLH using the conventional approach, whereas 24 cases received CLH with 3DP technology and ICG fluorescent navigation. Preoperative data were compared between the two groups. In the 3DP group, we modified the surgical strategy of four patients (4/24, 16.7%) due to real-time intraoperative navigation with 3DP and ICG fluorescent imaging technology. We did not modify the surgical strategy for any patient in the non-3DP group (P = 0.02). There were no significant differences between the non-3DP and 3DP groups regarding operating time (297.7±104.1 min vs. 328.8±110.9 min, P = 0.15), estimated blood loss (400±263.8 ml vs. 345.8±356.1 ml, P = 0.52), rate of conversion to laparotomy (3/30 vs. 2/24, P = 0.79), or pathological outcomes including the incidence of microscopical R0 margins (28/30 vs. 24/24, P = 0.57). Additionally, there were no significant differences in postoperative complications or recovery conditions between the two groups. No instances of 30- or 90-day mortality were observed.

Conclusion

The optimal surgical strategy for CLH can be chosen with the help of 3DP technology and ICG fluorescent navigation. This modified procedure is both safe and effective, but without improvement of intraoperative and short-term outcomes.

Superficial Temporal Artery and Vein as Alternative Recipient Vessels for Intraoral Reconstruction With Free Flaps to Avoid the Cervical Approach With the Resulting Need for Double Flap Transfer in Previously Treated Necks

Background

Microvascular reconstruction remains challenging in previously operated and irradiated patients, especially when double flaps seem to be the only solution due to osteoradionecrosis. An alternative reconstructive option could be microvascular anastomosis to the temporal vessels to avoid the obligatory cervical incision.

Methods and Materials

All consecutive cases between January 2013 and 2020 that underwent either mandibular resection and reconstruction with a free fibula flap (FFF) and another soft tissue flap (group I) or pure intraoral resection and reconstruction with an FFF or radial forearm flap (RFF) with temporal microvascular anastomosis (group II) were included. Patients’ general information, indication and extent of surgery, time of ischemia, time of total surgery, and duration of hospital stay as well as incidence of complications were retrospectively recorded and analyzed.

Results

Seventeen (group I) and 11 (group II) cases were included. In group I, FFF was combined with RFF (n = 9), anterolateral thigh flap (ALT, n = 7), or latissimus dorsi flap (n = 1). Group II consisted of six FFFs and five RFFs. Operation time and hospitalization duration were significantly shorter in group II (p < 0.001 and p = 0.025), whereas ischemic time of FFF was significantly shorter in group I (p = 0.002). All patients in group I required a tracheostomy, while only four cases in group II did (p = 0.004). The complication rate regarding hematoma removal, revision of anastomosis, flap loss, delirium, sepsis, pleural effusion, pneumonia, and pulmonary artery embolism showed no significant differences between the two groups.

Conclusions

The superficial temporal vessels served as versatile recipient vessels for intraoral mandibular and soft tissue reconstruction and led to reduced operation time, hospitalization duration, and indication for a primary tracheostomy. Thus, this approach may help to avoid cervical incision for reconstruction in irradiated patients.

Current Trends in the Reconstruction and Rehabilitation of Jaw following Ablative Surgery

Simple Summary

The Maxilla and mandible provide skeletal support for of the middle and lower third of our faces, allowing for the normal functioning of breathing, chewing, swallowing, and speech. The ablative surgery of jaws in the past often led to serious disfigurement and disruption in form and function. However, with recent strides made in computer-assisted surgery and patient-specific implants, the individual functional reconstruction of the jaw is evolving rapidly and the prompt rehabilitation of both the masticatory function and aesthetics after jaw resection has been made possible. In the present review, the recent advancements in jaw reconstruction technology and future perspectives will be discussed.

Abstract

The reconstruction and rehabilitation of jaws following ablative surgery have been transformed in recent years by the development of computer-assisted surgery and virtual surgical planning. In this narrative literature review, we aim to discuss the current state-of-the-art jaw reconstruction, and to preview the potential future developments. The application of patient-specific implants and the “jaw-in-a-day technique” have made the fast restoration of jaws’ function and aesthetics possible. The improved efficiency of primary reconstructive surgery allows for the rehabilitation of neurosensory function following ablative surgery. Currently, a great deal of research has been conducted on augmented/mixed reality, artificial intelligence, virtual surgical planning for soft tissue reconstruction, and the rehabilitation of the stomatognathic system. This will lead to an even more exciting future for the functional reconstruction and rehabilitation of the jaw following ablative surgery.

Surgical Margins After Computer-Assisted Mandibular Reconstruction: A Retrospective Study

Purpose: The use of virtual surgical planning in head and neck surgery is growing strongly. In the literature, its validity, accuracy and clinical utility for mandibular reconstruction are widely documented. Virtual planning of surgical bone resection and reconstruction takes place several days before surgery and its very sensitive nature can negatively affect an intervention aimed at maximum precision in term of oncological safety. Methods: The study focuses on a retrospective evaluation of the surgical margins in 26 consecutive cases with oral cavity malignancy and who underwent computer-assisted mandibular resection/reconstruction guided by the different types of bone, periosteal and peri-mandibular tissue involvement. The goal was to analyze the strategic and technical aspects useful to minimize the risk of positive or close margins and to vary the reconstructive strategy in the case of intraoperative findings of a non-radical planned resection. Results: No intraoperative or perioperative complications occurred. In 20 patients, virtual surgical planning permitted mandibular reconstruction to be performed using composite fibular free flaps, characterized by high accuracy and negative bone margins. In the remaining 6 patients, also virtually planned but otherwise reconstructed due to poor general condition (advanced age, severe comorbidity), negative bone margins were obtained. Intraoperative enlargement of the resection was carried out in one case and positive soft tissue margins were observed in another case. Conclusion: The results were satisfactory in terms of oncological radicality and precision. The functional benefits and reduction in operating times, previously demonstrated in other articles also by the authors, seem to justify the side effects related to the risk of modifying the planned surgery. During virtual planning, the surgeons must bear in mind that an unexpected progression of the tumor or a limited planned resection will entail modifying the extent of the resection intraoperatively and nullifying the virtual planning on which the reconstruction was based. Further investigations are necessary to clarify all aspects of virtual surgical planning in this setting.