BACKGROUND: Precision surgery is becoming increasingly important in the field of Orthopaedic Oncology. Image-guided percutaneous cryosurgery (CRA) has emerged as a valid treatment modality for extra-abdominal desmoid tumors (EDTs). To date, most CRA procedures use CT-based guidance which fails to properly characterize tumor segments. Computer-guided MRI navigation can address this issue however, the lack of a fixed landmark for registration remains a challenge. Successful CRA correlates directly with precision approaches facilitated by intraoperative imaging guidance. This is the first study that attempts to assess the feasibility and efficacy of a novel approach of using skin fiducial markers to overcome the challenge of a MRI-based navigation CRA for symptomatic or progressive EDTs.
METHODS: In this retrospective study conducted between 2018 and 2020, 11 patients at a single center with symptomatic or progressive EDTs were treated with CRA using intraoperative MRI navigation. Fifteen cryosurgery procedures were performed, each adhering to a personalized pre-operative plan. Total tumor size, viable and non-viable portions pre- and post-operation, and SF-36 questionnaire evaluating subjective health were recorded.
RESULTS: All CRAs demonstrated 100% adherence to the predetermined plan. Overall, tumor size decreased Median= -56.9% [-25.6, -72.4]) with a reduction in viable tissue, (Median= -80.4% [-53.3, -95.2]). Four patients required additional CRAs. Only one patient\'s tumor did not reduce in size. One patient suffered from local muscle necrosis. Pre-operation, the average physical and mental scores 41.6 [29.4, 43] and 26.3 [17.6, 40.9] respectively. Post-operation, the average physical and mental scores were 53.4[38, 59.7] and 38 [31.2, 52.7] respectively.
CONCLUSIONS: These findings provide an early indication of the feasibility and efficacy of performing percutaneous cryosurgery using skin fiducial marker registration for MRI-computed navigation to treat EDTs safely. Larger cohorts and multicenter evaluations are needed to determine the efficacy of this technique.

BACKGROUND: Surgical intervention for spontaneous pneumothorax typically includes mechanical pleurodesis that frequently utilizes a Bovie scratch pad given its universal presence, low cost and ease of use. The pad is folded on itself after dividing it in half, allowing easier passage through the smaller incisions. However, unintentional foreign body retention may occur during the course of an operation leading to reoperations or even worse complications. This case is reported to raise awareness that dividing the scratch pad may allow the embedded radio-opaque marker to fall out and become retained as a foreign body.
METHODS: The patient is a 41 year-old female who presented with shortness of breath secondary to spontaneous pneumothorax. Chest CT scan showed apical blebs. The patient underwent video assisted thorascopic surgery (VATS) with bleb resection and mechanical pleurodesis using a divided and folded bovie scratch pad. Postoperative chest x-ray showed a retained foreign body. Reoperation confirmed this to be the radio-opaque marker of the scratch pad and was removed. The patient did well and was discharged the following day.
CONCLUSIONS: Dividing the bovie scratch pad may damage and \"weaken\" the product allowing the radio- opaque marker to fall out during its use for pleurodesis and should be discouraged. Recommendation is made of using the scratch pad as a whole and not dividing it. Retained radio-opaque marker of bovie scratch pad during VATS mechanical pleurodesis.

Radiation therapy for liver tumors has been shown to provide a local control and overall survival benefit in patients with primary or oligometastatic liver tumors. However, accurate delineation of the target volume in intraabdominal tumors can be limited by diaphragmatic motion. In addition to image guidance during radiation therapy, computed tomography (CT)-guided fiducial marker placement can improve the accuracy of radiation treatment and optimize tumor control. Fiducial marker placement is often indicated in stereotactic body radiation therapy (SBRT) due to the ablative doses used as well as in proton therapy given that these markers are clearly visible on orthogonal kV image guidance and studies have suggested that their placement in liver tumors offers improved local control. However, fiducial marker migration is a rare risk associated with fiducial placement for which literature remains scarce. We report two separate cases of fiducial marker migrations from the liver into the inferior vena cava and right atrium which occurred following CT-guided placement without any resultant toxicity. Imaging using contrast-enhanced or volume navigation ultrasound techniques during fiducial marker deployment may mitigate the risk of fiducial marker migration and potential end-organ injury. Alternative techniques for motion management such as inspiratory or expiratory breath hold or use of residual lipiodol on imaging in patients who have undergone transarterial chemoembolization (TACE) should be considered as well to avoid potential complications from fiducial marker placement.

Dynamic Navigation is a computer-aided technology that allows the surgeon to track the grip instruments while preparing the implant site in real time based on radiological anatomy and accurate pre-operative planning. The support of this technology to the zygoma implant placement aims to reduce the risks and the errors associated with this complex surgical and prosthetic treatment. Various navigation systems are available to clinicians currently, distinguished by handling, reliability, and the associated economic and biological benefits and disadvantages. The present paper reports on the different protocols of dynamic navigations following a standard workflow in correlation with zygomatic implant supported rehabilitations and describes a case of maxillary atrophy successfully resolved with this technology. An innovative and minimally invasive dynamic navigation system, with the use of an intraoral anchored trust marker plate and a patient reference tool, has been adopted to support the accurate insertion of four zygomatic implants, which rapidly resolved maxillary atrophy from a 75-year-old male system. This approach provided an optimal implant placement accuracy reducing surgical invasiveness.

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BACKGROUND: Stereotactic radiotherapy is a useful therapeutic modality in patients with lung cancer and patients with pulmonary metastases who cannot tolerate, are not candidates for, or do not want surgery. Successful use of radial endobronchial ultrasound (EBUS) and navigation bronchoscopy to guide the placement of the fiducials required for stereotactic radiotherapy in peripheral lung lesions has been previously reported. We present the first series of patients in which convex-probe EBUS was used to deliver fiducials to hilar and mediastinal lymph nodes as well as central thoracic lesions.
METHODS: Retrospective case series of 5 patients in which convex-probe EBUS was used to place fiducials in central lesions.
RESULTS: Fiducial markers were successfully placed in all 5 patients and were durable. There were no procedure-related complications.
CONCLUSIONS: Convex-probe EBUS is a useful tool in the placement of fiducial markers in patients with malignant lymphadenopathy and central parenchymal lung lesions.

BACKGROUND: Lipiodol injections were administered in the head and neck area to improve gross tumor volume (GTV) definition for small-volume re-irradiation of a 63-year-old previously irradiated patient with a second tumor of the oropharynx in the posterior wall with longitudinal ligament infiltration (cT4cN0cM0).
METHODS: The patient had dialysis-depending renal failure. On diagnostic computed tomography (CT), which was performed with intravenous contrast agent, the tumor in the oropharynx was not detectable. Because of dialysis-depending renal failure comorbidity, no contrast agent was applied in the planning CT and in the diagnostic magnetic resonance imaging (MRI) study. In each cross-sectional imaging study performed, the GTV, especially in craniocaudal extensions, was not safely delineable. Therefore, craniocaudal tumor margins were pharyngoscopically marked with Lipiodol injections, an iodine-containing contrast agent.
RESULTS: In a second planning CT, the GTV could be defined with the help of the Lipiodol marks and small-volume re-irradiation was performed. No Lipiodol-associated side effects occurred in the patient.
CONCLUSIONS: In the present case, the use of Lipiodol injections at the tumor margins facilitated the definition of the GTV.

Innovations in endovascular tools have permitted an increasingly broad range of neurovascular lesions to be treated via minimally invasive methods. However, some device modifications may carry additional risks, not immediately apparent to operators. A patient with a symptomatic, partially thrombosed basilar apex aneurysm was allocated balloon-assisted coiling. Attempts were made to place a microwire across the basilar apex through the posterior communicating artery. Overlapping courses of the posterior cerebral and posterior choroidal arteries on the roadmap images were not recognized and a flanged-tip microwire was inadvertently advanced deep into the choroidal artery. Following the wire with a microcatheter led to binding of arterial tissue within the microcatheter. Removing the wire led to an avulsion of the choroidal artery and a severe hemorrhagic complication which proved fatal. Tissue was identified on the tip of the guidewire. Pathology showed layers of vascular tissue within the laser-cut flanges of the distal wire tip. A similar complication, also fatal, occurred during balloon angioplasty of a distal vertebral artery, when an exchange wire was accidently introduced into a perforator from a posterior cerebral artery. Ex vivo catheterization of distal mesenteric arterial branches showed that the wall of small arteries can be entrapped by laser-cut, flanged, but not by smooth guidewire tips. Microwires with a flanged instead of smooth distal tip, when placed into small caliber vessels, may cause hemorrhagic complications from avulsions*.

Safe clinical practice in implant dentistry requires an accurate investigation of the availability of bone for implant placement and the avoidance of critical anatomical structures. Modern imaging techniques using computed tomography (CT) and cone beam computed tomography (CBCT) provide the clinician with the required information. The imaging thus obtained provides accurate representation of the height, width and length of the available bone. In addition, whenever adequate radiation dose is used, accurate information about the bone density in Hounsfield units can be obtained. Important spatial information regarding the orientation of the ridges and the relationship to the proposed prosthetic reconstruction can be obtained with the aid of radiopaque templates during the acquisition of CT scan data. Modern software also provides the facility to decide interactively upon the positioning of the implants and is able to relate this to a stereolithographic model constructed from the imaging data. A surgical guide for the accurate positioning of the implants can be constructed. The construction of screw retained prostheses is fraught with difficulties regarding the accuracy of the construction. Accurate fit of the prosthesis is difficult to obtain due to the inherent errors in impression taking, component discrepancies, investing and casting inaccuracies. CAD/CAM technology eliminates the inaccuracies involved with the investing and casting of superstructures.

OBJECTIVE: Mucosal thickness should be considered in implant treatment planning. Needle probing to measure mucosal thickness is invasive and therefore not used in routine diagnosis. The \"puffed cheek\" method is an established technique to visualize the vestibule in computed tomography (CT). As CT assesses bone availability, a simultaneous mucosal thickness measurement would be useful. The aim of this study was to evaluate the reliability of mucosal thickness measurement in CT with distended cheeks.
METHODS: Buccal maxillary mucosa thickness was evaluated at four measurement sites in the incisor and molar area of 11 patients. Each site was evaluated via CT with cheek distension and needle probing. Measurement area was identified with the aid of a thermoplastic splint to localize the exact position by a gutta-percha marker point. The comparison between the two methods was performed by Bland-Altman diagram.
RESULTS: The mean clinical thickness was 1.17 mm (±0.31) compared to 1.11 mm (±0.31) in CT evaluation. The mean difference between the two methods was 0.07 mm (±0.40; CI-0.14;0.12, P = 0.88, Krippendorff α = 0.38). According to Bland-Altman diagram the mucosal thickness may diverge by up to 0.9 mm from the radiologic thickness.
CONCLUSIONS: The two measurement methods may not be interchangeably used. As additional information to three-dimensional bone analyses, CT may be performed as a pre-operative soft tissue analysis at most implant sites with distended cheeks. Nevertheless, this method yields less valid and reliable results than the gold standard.