Controversies in orthopaedic oncology.

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Mechanical failure of distal femur mega prosthesis due to polyaryl-ether-ether-ketone (PEEK) hinge component.

BACKGROUND: Polyaryl-ether-ether-ketone (PEEK) has gained popularity as a substrate for orthopaedic hardware due to its desirable properties such as heat and deformation resistance, low weight, and ease of manufacturing. However, we observed a relatively high failure rate of PEEK-based hinges in a distal femur reconstruction system. In this study, we aimed to evaluate the proportion of patients who experienced implant failure, analyse the mechanism of failure, and document the associated clinical findings. METHODS: We conducted a retrospective cohort study, reviewing the medical charts of 56 patients who underwent distal femur resection and reconstruction with a PEEK Optima hinge-based prosthesis between 2004 and 2018. Concurrently, we performed a clinical and biomechanical failure analysis. RESULTS: PEEK component failure occurred in 21 out of 56 patients (37.5%), with a mean time to failure of 63.2 months (range: 13-144 months, SD: 37.9). The survival distributions of PEEK hinges for males and females were significantly different (chi-square test, p-value = 0.005). Patient weight was also significantly associated with the hazard of failure (Wald's test statistic, p-value = 0.031). DISCUSSION: Our findings suggest that PEEK hinge failure in a distal femur reconstruction system is correlated with patient weight and male gender. Retrieval analysis revealed that failure was related to fretting and microscopic fractures due to cyclic loading, leading to instability and mechanical failure of the PEEK component in full extension. Further assessment of PEEK-based weight bearing articulating components against metal is warranted.

Does cryotherapy decrease the local recurrence rate in the treatment of an aneurysmal bone cyst? A comparative assessment.

Curettage with or without the use of adjuvants is the standard of care in the treatment of an aneurysmal bone cyst (ABC). Historically, our approach combined curettage, high-speed burr drilling, and cryoablation. However, treatments varied based on age, tumor location, and surgeon preference. We asked: (1) Does cryoablation in addition to curettage and burr drilling decrease the local recurrence rates? (2) Are there any risk factors for the local recurrence rate? (3) Does cryoablation improve postsurgical functional outcomes in these patients? Patients treated for an ABC, between January 2006 and December 2019 were included in this retrospective analysis. Patient and surgical characteristics, such as age, gender, tumor location, type of treatment, time of follow-up, recurrence rate, and functional outcome measured by the Musculoskeletal Tumor Society Score 1993 (MSTS93) score were compared between those treated with and without cryoablation. Both groups, without cryoablation (n = 88) and with cryoablation (n = 42), showed no significant difference in local recurrence rates (9.1% vs. 7.1%, p = 0.553) and functional outcomes as measured by the MSTS93 score (28.9 vs. 27.8, p = 0.262). Risk factors analyzed did not significantly affect local recurrence risk, except for secondary ABC diagnosis (p = 0.017). The cryoablation group had a more extended follow-up (45.6 vs. 73.2 months, p < 0.001), reflecting a shift in practice over time. We found no significant difference in local recurrence rate or functional outcome in patients treated with or without cryoablation. Formal curettage with additional high-speed burr drilling provides effective tumor control and favorable functional outcomes, negating the need for adjuvant cryoablation.

MRI-based navigated cryosurgery of extra-abdominal desmoid tumors using skin fiducial markers: a case series of 15 cases.

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. CONCLUSION: 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.

Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the upper extremity: A series of 19 cases.

The surgical treatment for osteoid osteoma (OO) in the upper extremity is challenging due to the difficulty in locating the lesion and the crowding of sensitive structures within the anatomy. This study aimed to describe the outcomes of navigated minimally invasive radiofrequency ablation and those of navigated mini open-intralesional curettage in treating these lesions. Nineteen consecutive patients with OO in the upper limb who underwent navigated surgery were included. The average QuickDASH and Numeric Pain Rating Scale improved from 62.2 ± 23.7 to 11.7 ± 16.9 and from 8.1 ± 1.6 to 0.5 ± 1.8, respectively (p < .01 each) following the procedure. Two complications were recorded: one patient had persistent radial nerve palsy, and one patient had transient partial radial nerve weakness. In conclusion, navigation is an important tool in the surgical treatment of OO in the upper limb. A mini open approach to identify and protect neurovascular structures is recommended.

Virtual reality and 3D printing in clinical anesthesia: a case series of two years' experience in a single tertiary medical centre.

PURPOSE: Anatomically correct patient-specific models made from medical imaging can be printed on a three-dimensional (3D) printer or turned into a virtual reality (VR) program. Until recently, use in anesthesia has been limited. In 2019, the anesthesia department at Tel Aviv Medical Center launched a 3D program with the aim of using 3D modelling to assist in preoperative anesthesia planning. METHODS: A retrospective review of all relevant patients between July 2019 and June 2021 referred for preoperative airway planning with 3D modelling. Patient files were reviewed for correlation between the model-based airway plan and the actual airway plan, the type of model used, and any anesthetic complications related to airway management. RESULTS: Twenty patients were referred for 3D modelling. Of these, 15 models were printed, including 12 children requiring one lung ventilation. Five patients had VR reconstructions, including three with mediastinal masses. One patient had both a 3D-printed model and a VR reconstruction. There were two cases (10%) where the model plan did not correlate with the final airway plan and one case where a model could not be created because of poor underlying imaging. For the remaining 17 cases, the plan devised on the model matched the final airway plan. There were no anesthetic complications. CONCLUSIONS: Three-dimensional modelling and subsequent printing or VR reconstruction are feasible in clinical anesthesia. Its routine use for patients with challenging airway anatomy correlated well with the final clinical outcome in most cases. High-quality imaging is essential.

RéSUMé: OBJECTIF: Des modèles anatomiquement corrects spécifiques à un·e patient·e réalisés à partir de l'imagerie médicale peuvent être imprimés sur une imprimante tridimensionnelle (3D) ou transformés en programme de réalité virtuelle (RV). Jusqu'à récemment, l'utilisation de cette modalité était limitée en anesthésie. En 2019, le service d'anesthésie du centre médical de Tel Aviv a lancé un programme 3D dans le but d'utiliser la modélisation 3D pour faciliter la planification préopératoire de l'anesthésie. MéTHODE: Nous avons réalisé un examen rétrospectif de toute la patientèle concernée référée pour une planification préopératoire des voies aériennes avec modélisation 3D entre juillet 2019 et juin 2021. Les dossiers des patient·es ont été examinés pour déterminer la corrélation entre le plan de prise en charge des voies aériennes fondé sur le modèle et le plan fondé sur les voies aériennes réelles, le type de modèle utilisé et toute complication anesthésique liée à la prise en charge des voies aériennes. RéSULTATS: Vingt patient·es ont été référé·es pour la modélisation 3D. À partir de cette cohorte, 15 modèles ont été imprimés, dont 12 pour des enfants nécessitant une ventilation pulmonaire. Cinq patient·es ont bénéficié de reconstructions en RV, dont trois avec des masses médiastinales. Un modèle imprimé en 3D et une reconstruction en RV ont été créés pour une personne. Il y a eu deux cas (10 %) où le plan modèle n'était pas corrélé avec le plan des voies aériennes final et un cas où il n'a pas été possible de créer un modèle en raison d'une mauvaise imagerie sous-jacente. Pour les 17 cas restants, le plan conçu sur le modèle correspondait au plan final de prise en charge des voies aériennes. Il n'y a pas eu de complications anesthésiques. CONCLUSION: La modélisation tridimensionnelle et l'impression ultérieure ou la reconstruction en RV sont réalisables en anesthésie clinique. Leur utilisation systématique pour les patient·es présentant une anatomie difficile au niveau des voies aériennes était bien corrélée avec le résultat clinique final dans la plupart des cas. Une imagerie de haute qualité est essentielle.

Favorable outcomes of navigated percutaneous ablation and cementoplasty of bone metastasis in the extremities and pelvis-a case series of 13 cases.

OBJECTIVES: Palliative treatment options for bone metastasis are limited, especially in cases where standard protocols have already failed. The purpose of this study was to evaluate the efficacy and safety of percutaneous ablation, either by cryoablation or radiofrequency, combined with percutaneous cementoplasty using cone-beam guided navigation. The objective was to relieve symptoms and improve functionality in patients suffering from pain secondary to bone metastases, as well as evaluate local disease progression post ablation. METHODS: We conducted a retrospective study of 13 patients (average age 63.6 ± 9.8, nine females) with symptomatic skeletal metastases treated using 3D imaging with navigation and followed for at least 12 months. The treatment protocol was implemented either after failure of first line treatment, or as first line when mechanical instability was present. Percutaneous lesion ablation was performed along with percutaneous cementation. RESULTS: In this study, we observed a statistically significant decrease in pain. The mean Visual Analog Scale pain score decreased from 7.1 ± 0.4 prior to CRA/RFA to 2.2 ± 0.3 after the procedure (p < 0.001). At the 12-months follow-up, all patients were able to ambulate with no assistance (Eastern Cooperative Oncology Group <2). One minor adverse event (paresthesia) and one major adverse event (drop foot) were resolved at 1 year of follow-up. CONCLUSIONS: Treatment of bone metastasis with RFA and CRA in conjunction with cementoplasty using Cone-beam computed tomography navigation provides patients with significant palliative outcomes and in most cases, local tumor control.

Three-dimensional technologies in presurgical planning of bone surgeries: current evidence and future perspectives.

BACKGROUND: The recent development of three-dimensional (3D) technologies introduces a novel set of opportunities to the medical field in general, and specifically to surgery. The preoperative phase has proven to be a critical factor in surgical success. Utilization of 3D technologies has the potential to improve preoperative planning and overall surgical outcomes. In this narrative review article, the authors describe existing clinical data pertaining to the current use of 3D printing, virtual reality, and augmented reality in the preoperative phase of bone surgery. METHODS: The methodology included keyword-based literature search in PubMed and Google Scholar for original articles published between 2014 and 2022. After excluding studies performed in nonbone surgery disciplines, data from 61 studies of five different surgical disciplines were processed to be included in this narrative review. RESULTS: Among the mentioned technologies, 3D printing is currently the most advanced in terms of clinical use, predominantly creating anatomical models and patient-specific instruments that provide high-quality operative preparation. Virtual reality allows to set a surgical plan and to further simulate the procedure via a 2D screen or head mounted display. Augmented reality is found to be useful for surgical simulation upon 3D printed anatomical models or virtual phantoms. CONCLUSIONS: Overall, 3D technologies are gradually becoming an integral part of a surgeon's preoperative toolbox, allowing for increased surgical accuracy and reduction of operation time, mainly in complex and unique surgical cases. This may eventually lead to improved surgical outcomes, thereby optimizing the personalized surgical approach.

Internal Hemipelvectomy for primary bone sarcomas using intraoperative patient specific instruments- the next step in limb salvage concept.

BACKGROUND: During pelvic Sarcoma resections, Surgeons often struggle to obtain negative margins while minimizing collateral damage and maintaining limb function. These complications are usually due to the complex anatomy of the pelvis. Here we present an accurate 3D surgical approach, including pre-operative printing of models and intraoperative patient-specific instruments (PSIs) for optimizing pelvic sarcoma resections. METHODS: This single-center retrospective study (N = 11) presents surgical, functional, and oncological outcomes of patients (average age 14.6 +/- 7.6 years, 4 males) who underwent pelvic sarcoma resections using a 3D surgical approach between 2016 and 2021. All patients were followed up for at least 24 months (mean = 38.9 +/- 30.1 months). RESULTS: Our results show promising surgical, oncological, and functional outcomes. Using a 3D approach, 90.9% had negative margins, and 63.6% did not require reconstruction surgery. The average estimated blood loss was 895.45 ± 540.12 cc, and the average surgery time was 3:38 ± 0.05 hours. Our results revealed no long-term complications. Three patients suffered from short-term complications of superficial wound infections. At 24 month follow up 72.7% of patients displayed no evidence of disease. The average Musculoskeletal Tumor Society (MSTS) score at 12 months was 22.81. CONCLUSION: 3D technology enables improved accuracy in tumor resections, allowing for less invasive procedures and tailored reconstruction surgeries, potentially leading to better outcomes in function and morbidity. We believe that this approach will enhance treatments and ease prognosis for patients diagnosed with pelvic sarcoma and will become the standard of care in the future.

Radiation Therapy Before Repeat Wide Resection for Unplanned Surgery of Soft Tissue Sarcoma ("Oops" Operation) Results in Improved Disease-Free Survival.

Purpose: The main goal of treatment of soft-tissue sarcomas is achieving wide negative margins to improve local control and prevent recurrence. The role of radiation therapy (RT) is well established in sarcomas of the extremities; however, its role in unplanned surgery of soft-tissue sarcoma (when a mass presumed to be benign is resected and the pathology comes back as sarcoma, usually referred to as an "oops" operation) is inconclusive. This article reports on the effect of RT after an unplanned surgery before the reresection. Methods and Materials: A total of 65 patients who had undergone an unplanned resection of a postoperatively diagnosed soft-tissue sarcoma were treated with RT and/or surgery and retrospectively evaluated for disease progression. Treatment started with RT in 49 cases (75.4%), including 8 cases of no further surgery. A repeat wide resection was performed directly after the initial surgery in 16 patients, followed by RT in 15 of them. Results: The disease recurred in 7 out of 49 patients (14.3%) who received RT first and in 9 out of 16 (56.25%) who underwent reoperation before RT (P = .001). Disease-free progression was higher in cases of low-grade malignancy (P = .049). A clinical diagnosis of lipoma was associated with a better outcome than a diagnosis of nonlipoma (P = .034). The presence of residual tumor at reoperation did not affect disease control. Patient age, time between symptom onset and diagnosis, hospital level of initial diagnosis (tertiary versus nontertiary), anatomic site, tumor size, and margin status at the initial excisional biopsy were not significantly correlated with the outcome. Conclusion: Initiating treatment with RT followed by unplanned "oops" resection of soft-tissue sarcoma before the reresection improved disease-free survival as opposed to vice versa.

Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the foot and ankle - A series of 14 cases.

BACKGROUND: The surgical treatment for osteoid osteoma (OO) in the foot and ankle is challenging. It is difficult to locate the lesion and the anatomy is crowded by sensitive structures. The purpose of this study was to describe the outcomes of navigated mini open-intralesional curettage (NMIC) or navigated minimally invasive radiofrequency ablation (NMRFA) in treating these lesions. METHODS: All patients who underwent surgery for OO in the foot and ankle between 2015 and 2020 were included. O-arm navigation was used in All procedures. The choice of NMIC versus NMRFA was made by the surgeon according to the location of the lesion and its proximity to sensitive anatomic structures. RESULTS: Fourteen patients were included. Ten were operated by NMRFA and 4 by NMIC. All patients' symptoms related to OO resolved following a single procedure. Average AOFAS score increased by 18.7 (P < .001). Three patients had the following complications: pathologic fracture, superficial infection and transient deep peroneal nerve sensory loss. CONCLUSION: Navigated surgical treatment of OO in the foot and ankle is accurate, efficient and safe.

Three dimensional printing as an aid for pre-operative planning in complex cases of total joint arthroplasty: A case series.

Purpose: Digital templating is an essential aspect of pre-operative planning for total joint arthroplasty procedures. For complex cases of joint reconstruction, the standard templating software is insufficient to achieve the desired accuracy. 3D printing significantly aids the pre-operative planning in complicated cases of joint reconstruction and offers immense potential towards improving outcomes in these cases. The purpose of the present study is to present the various ways in which 3D printing has aided our department in facilitating complex cases of lower extremity reconstruction. Methods: Data was retrospectively retrieved for all patients that underwent total hip arthroplasty (THA) and total knee arthroplasty (TKA) with the aid of 3D printing technology at our institution between January 2016-February 2021. Patient pain was determined before and after surgery using the visual analogue scale (VAS). Patient reported outcome measures (PROMs) were additionally analyzed using the hip disability and osteoarthritis outcome score (HOOS) and knee injury and osteoarthritis outcome score (KOOS). Results: The final study population consisted of 39 patients that underwent TKA or THA procedures with the use of 3D printing. Twenty-four (61.5%) of the surgeries in the study were THA procedures, whereas 15 (38.5%) were TKA procedures. The average VAS for patients reduced from 8.4% before surgery to 5.4% after surgery (p < 0.001). The mean KOOS of patients that underwent TKA was 17.33 ± 9.33 (43%) and the mean HOOS of patients that underwent THA was 13.79 ± 6.6 (42%). Conclusions: The following series demonstrates the ability by which 3D printing facilitates complex cases of hip and knee reconstruction. 3D printing offers an improvement in understanding of patient specific anatomy, enhancing patient outcomes. Departments should consider the use of 3D printing technology as an adjunct when performing complex cases of lower extremity reconstruction.

Intercalary and geographic lower limb tumor resections with the use of 3D printed Patient Specific Instruments- when less is more.

Background: Primary bone sarcomas are associated with critically sized bone defects and require complete resection with negative margins. Recent advancements in health care have pioneered novel approaches such as the implementation of 3D surgical technologies. This study presents oncological and functional outcomes following tumor resections of long bones with the use of customized 3D-printed Patient Specific Instruments (PSIs). Methods: This single-center retrospective study is comprised of seventeen patients who underwent either intercalary (N = 12) or geographic (N = 5) resections with various reconstruction methods including allograft (N = 8), vascularized fibula (Capanna) (N = 7), and 3D printed customized titanium implants (N = 2), between the years 2016-2020. All patients were operated on with a 3D surgical workflow, including intraoperative PSIs, and were followed up postoperatively for at least 12 months (average 31.40 ± 12.13 months) to assess oncological and functional outcomes. Results: All patients demonstrated negative surgical margins, apart from one patient who had planned positive margins. Three patients suffered from short-term complications, and three patients underwent revision surgery due to graft non-union or pathological fracture. One patient suffered from local recurrence and underwent above-knee amputation. Three patients suffered from lung metastasis. MSTS at 12-month follow-up was 26.9.±5.87. Conclusion: Customized 3D-printed osteotomy PSIs provide surgeons with a novel tool for optimizing bone resection and reconstruction in long bones surgeries, thus minimizing overall tissue trauma and reducing the risk of damage to nervous and vascular structures. This study demonstrates that the use of PSIs has the potential to improve functional and oncological outcomes. We believe that this technique will become increasingly popular in the future as a widely applicable, highly accurate, cost-effective optimization tool.

In-hospital production of 3D-printed casts for non-displaced wrist and hand fractures.

OBJECTIVES: To examine the clinical feasibility and results of a multidisciplinary workflow, employing rapid three-dimensional (3D) scanning and modeling software along with a high-speed printer, for in-hospital production of patient-specific 3D-printed casts, for the treatment of non-displaced wrist and hand fractures. METHODS: Consenting adult patients admitted to the emergency department (ED) due to wrist or hand fractures between January and February 2021 were prospectively enrolled. The study participants underwent conversion of the standard plaster of Paris cast to a 3D-printed cast one week after the ED visit, and follow-up examinations were performed around two, six, and twelve weeks later. The primary objective was to examine the clinical feasibility in terms of complexity and length of the overall procedure. Secondary outcomes were patient-reported impressions and radiological results. RESULTS: Twenty patients (16 males, mean age 37 ± 13.1 years) were included. The entire printing workflow took a mean of 161 ± 8 min. All patients demonstrated clinical improvement and fracture union at final follow-up, with no pressure sores or loss of reduction. Patient-reported comfort and satisfaction rates were excellent. The mean Visual Analog Scale was 0.9 ± 1.1 and 0.6 ± 1, and the mean Disabilities of the Arm, Shoulder, and Hand score was 18.7 ± 9.5 and 7.6 ± 7.6 at 2 and 6 weeks after application of the 3D-printed cast, respectively. CONCLUSION: The in-hospital workflow was feasible and efficient, with excellent clinical and radiographic results and high patient satisfaction and comfort rates. Our medical center now routinely provides this cast option for non-displaced wrist and hand fractures. LEVEL OF EVIDENCE: IV, Therapeutic Study.

In situ cryoablation of sacral Giant Cell Tumor using three-dimensional (3D) model: A case report.

Three-dimensional planning of in-situ (trans-sacral) image guided cryoablation provides a method to treat sacral GCTs that accommodates the intricacies of the pelvis offering a safer, more efficacious alternative. Here we report on IM a 23-year-old female with a sacral GCT. She presented to Tel Aviv Medical Center with ongoing pain as well as neurological symptoms. For six years, the patient was in-and-out of the hospital for Denosumab treatment and recurrent infections. Eventually, further treatment became necessary, and she was treated with image guided cryoablation. By six months follow-up, the patient was mobile and pain-free.

3D-printed Cutting Guides for Lower Limb Deformity Correction in the Young Population.

BACKGROUND: Three-dimensional (3D) virtual surgical planning technology has advanced applications in the correction of deformities of long bones by enabling the production of 3D stereolithographic models, patient-specific instruments and surgical-guiding templates. Herein, we describe the implementation of this technology in young patients who required a corrective osteotomy for a complex 3-plane (oblique plane) lower-limb deformity. PATIENTS AND METHODS: A total of 17 patients (9 males, average age 14.7 y) participated in this retrospective study. As part of preoperative planning, the patients' computerized tomographic images were imported into a post-processing software, and virtual 3D models were created by a segmentation process. Femoral and tibial models and cutting guides with locking points were designed according to the deformity correction plan. They were used for both planning and as intraoperative guides. Clinical parameters, such as blood loss and operative time were compared with a traditional surgical approach group. RESULTS: All osteotomies in the 3D group were executed with the use intraoperative customized cutting guides which matched the preoperative planning simulation and allowed easy fixation with prechosen plates. Surgical time was 101±6.2 minutes for the 3D group and 126.4±16.1 minutes for the control group. The respective intraoperative hemoglobin blood loss was 2.1±0.2 and 2.5+0.3 g/dL.Clinical and radiographic follow-up findings showed highly satisfactory alignment of the treated extremities in all 3D intervention cases, with an average time-to-bone union (excluding 2 neurofibromatosis 1 patients) of 10.3 weeks (range 6 to 20 wk). CONCLUSION: The use of 3D-printed models and patient-specific cutting guides with locking points improves the clinical outcomes of osteotomies in young patients with complex bone deformities of the lower limbs. LEVEL OF EVIDENCE: Level III.

Three dimensional printed models of the airway for preoperative planning of open Laryngotracheal surgery in children: Surgeon's perception of utility.

BACKGROUND: Preoperative planning of open laryngotracheal surgery is important for achieving good results. This study examines the surgeon's perception of the importance of using life size 3D printed models of the pediatric airway on surgical decision making. METHODS: Life-size three-dimensional models of the upper airway were created based on CT images of children scheduled for laryngotracheal-reconstruction and cricotracheal resection with anastomosis. Five pediatric airway surgeons evaluated the three-dimensional models for determining the surgical approach, incision location and length, graft length, and need for single or double-stage surgery of seven children (median age 4.4 years, M:F ratio 4:3). They rated the importance of the three-dimensional model findings compared to the direct laryngoscopy videos and CT findings for each domain on a validated Likert scale of 1-5. RESULTS: The mean rating for all domains was 3.6 ± 0.63 ("moderately important" to "very important"), and the median rating was 4 ("very important"). There was full agreement between raters for length of incision and length of graft. The between-rater agreement was 0.608 ("good") for surgical approach, 0.585 ("moderate") for incision location, and 0.429 ("moderate") for need for single- or two-stage surgery. CONCLUSION: Patient-specific three-dimensional printed models of children's upper airways were scored by pediatric airway surgeons as being moderately to very important for preoperative planning of open laryngotracheal surgery. Large-scale, objective outcome studies are warranted to establish the reliability and efficiency of these models.

Cryo-surgery for symptomatic extra-abdominal desmoids. A proof of concept study.

BACKGROUND AND OBJECTIVE: Extra abdominal desmoid tumors are rare, highly aggressive, and invasive benign soft tissue tumors. Current treatment modalities show high levels of recurrence and comorbidities. Cryo-surgery as an alternative was subsequently investigated. METHODS: In this retrospective, single center study 11 patients showing symptomatic tumors were treated with individualized cryo-surgery. Treatment protocol included preoperative planning using computer rendered 3D models, intraoperative navigation and execution using cone beam guidance, and postoperative magnetic resonance imaging image analysis using a gaussian mixture model software. Subjective outcomes were reported using Short Form Health Survey (SF-36) questionnaires. RESULTS: Sixteen ablations were performed, each demonstrating a complete match with the determined preoperative plan and model. A total of 9/11 (82%) of patients showed improvements in symptoms and a reduction in tumor volume while 2/11 (18%) did not. Average reduction in tumor volume and viable segments were 36.7% (p = 0.0397) and 63.3% (p = 0.0477), respectively. Mild complications according to the SIR Adverse Event Classification Guidelines were experienced in 3/16 (19%) ablations. SF-36 scores showed a statistically significant improvement (p = 0.0194) in the mental health category and a nonsignificant (p = 0.8071) improvement in the physical health category. CONCLUSION: Cryo-surgery using the three-phase protocol as described may improve the overall outcome of future ablation procedures.

Development and validation of a 3D printed antiviral ventilator filter - a comparative study.

BACKGROUND: The current coronavirus infectious disease 2019 (COVID-19) pandemic has caused unexpected pressure on medical supplies, interrupting supply chains and increasing prices. The supply of antiviral filters which form an essential part of the ventilator circuit have been affected by these issues. Three-dimensional (3D) printing may provide a solution to some of these issues. METHODS: We designed and tested 3D printed heat and moisture exchange (HME) and antiviral casing. For each casing we tested two different filter materials derived from a sediment water filter cartridge or 1.5-µm glass fiber filter paper. A polyurethane sponge was used for the HME. Each design was tested for circuit leak, circuit compliance, peak inspiratory pressure and casing integrity using methylene blue dye. RESULTS: We designed, produced, and tested two different types of antiviral filters with six different internal configurations. Overall, we tested 10 modified filter designs and compared them with the original commercial filter. Except for the combination of 1.5-µm filter paper and 5 mm sponge peak inspiratory pressure and circuit compliance of the filters produced were within the operating limits of the ventilator. All In addition, all filters passed the dye test. CONCLUSIONS: Our filter may be of particular importance to those working in low middle-income countries unable to compete with stronger economies. Our design relies on products available outside the healthcare supply chain, much of which can be purchased in grocery stores, hardware stores, or industrial and academic institutions. We hope that these HMEs and viral filters may be beneficial to clinicians who face critical supply chain issues during the COVID-19 pandemic.

Patient-specific computed tomography-based finite element analysis: a new tool to assess fracture risk in benign bone lesions of the femur.

BACKGROUND: Most benign active and latent lesions of proximal femur do not predispose a patient to a pathologic fracture. Nonetheless, there is a tendency to perform internal fixation due to the lack of accurate clinical tools that may reliably confirm low risk of pathologic fracture. As many as 30% of these surgeries may be unnecessary. A patient-specific CT-based finite element analysis may quantify bone strength and risk of fracture under normal weight-bearing conditions. METHODS: The clinical relevance of such finite element analysis was investigated in a retrospective study on a cohort of 17 patients. Finite element analysis results (high risk = indication for surgery, low or moderate risk = follow-up) were compared to actual clinical decisions (surgery vs follow-up). All patients predicted by the finite element analysis as high risk underwent internal fixation and had good outcomes (n = 6). FINDINGS: Four of the 11 low- and moderate-risk finite element analysis patients (36%) were operated immediately, and seven (64%) were either operated after a delay of at least 6 months or were never operated. None sustained a pathologic fracture. Patients who were predicted as low fracture risk by finite element analysis remained fracture-free for a minimal period of 6 months. Prediction of high risk of pathologic fracture by finite element analysis was in complete agreement with the conventional clinical evaluation. INTERPRETATION: We consider finite element analysis a promising decision support system for the management of patients with benign tumors of femur, and that it may reliably endorse the decision to withhold surgery for patients at low fracture-risk.