The Effect of the COVID-19 Pandemic on Pituitary Surgeries

PURPOSE

As the COVID-19 pandemic spread to the United States in 2020, there was an impetus towards postponing or ceasing non-urgent transsphenoidal pituitary surgeries to prevent spread of the virus. Some centers encouraged transcranial approaches for patients with declining neurologic function. However, no large-scale data exists evaluating the effects this had on national pituitary practice patterns.

METHODS

Pituitary surgeries in the National Inpatient Sample were identified from 2017-2020. Surgeries in 2020 were compared to the three years prior to determine any differences in demographics, surgical trends/approaches and perioperative outcomes. In 2020, there was a decline in overall pituitary surgeries (34.2 vs. 36.3%, odds ratio (OR) 0.88, p<0.001) yet transsphenoidal approaches represented a higher proportion of interventions (69.0 vs. 64.9%, p<0.001). Neurosurgical complications were higher (51.9 vs. 47.4%, OR 1.13, p<0.001) and patients were less likely to be discharged home (86.4 vs. 88.5%, OR 0.84, p<0.001). This was especially true in April 2020 during the first peak in COVID-19 cases when transcranial approaches and odds of mortality/complications were highest.

CONCLUSIONS

In 2020, transsphenoidal surgery remained the preferred approach for pituitary tumor resection despite initial recommendations against the approach to prevent COVID-19 spread. Pituitary surgeries had a higher risk of periprocedural complications despite accounting for preoperative comorbidities, COVID-19 infection status, and surgical approach, suggesting that an overwhelmed hospital system can negatively influence surgical outcomes in non-infected patients.

The evolution of poller screws

Compared to other techniques, poller screws with intramedullary nailing are technically simple, practical, and reproducible for the fixation of metaphyseal fractures. In addition, poller screws do not require special instruments or hardware and are minimally invasive. This review takes a historical perspective to evaluate poller screws holistically. A non-systematic search on PubMed was performed using 'Poller screw' or 'Blocking screw' to find early use of poller blocking screws. Relevant references from these primary studies were then followed up. In 1999, Krettek et al. first coined the term poller screws after the small metal bollards that block and direct traffic. Poller screws were introduced as an adjunct to aid the union of metaphyseal long bone fractures during intramedullary nailing. However, as more evidence was published, the true effectiveness of poller screws was not appreciated, leading to split opinions. Through our research, we have built upon our understanding of poller screws, and we present a novel classification of poller screws over the years while exploring our novel technique and what we believe to be the fourth generation of poller screws. Currently, there is a paucity of research focussing on poller screws. However, studying the original evidence regarding poller screws through the most recent articles has demonstrated a confusion of research in this field. Therefore, we suggest a more organised approach to classify the use of poller screws.

What are the Outcomes of Secondary Patella Resurfacing for Dissatisfaction Following Primary Knee Arthroplasty? A Systematic Review and Meta-Analysis of 604 Knees

BACKGROUND

Secondary patella resurfacing is often performed for dissatisfaction following primary knee arthroplasty where the native patella was retained. The purpose of this meta-analysis was to evaluate outcomes of secondary patella resurfacing.

METHODS

The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies reporting on patients who underwent secondary patella resurfacing after previous primary knee arthroplasty with retention of the native patella were considered eligible. The risk of bias was assessed using the Methodological Index for Non-Randomized studies tool. A random-effects model and the inverse-variance weighting method was used for meta-analysis. There were sixteen retrospective studies including 604 knees (594 patients) with a mean follow up of 42 months (range, 2 to 197).

RESULTS

An overall improvement in patient-reported outcomes (PROMs) was achieved in 53% of cases from pooled data available for 293 knees [95% Confidence Interval (CI) (0.44, 0.62), I2=68% - moderate heterogeneity]. The pooled proportion of patients satisfied with the procedure was 59% [95% CI (48, 68), I2 = 70% - moderate heterogeneity] in a sample size of 415. There was a minimal rate (2%) of complication incidence when performing secondary patella resurfacing and a pooled rate of revision surgery of 10%.

CONCLUSIONS

An improvement in pain, satisfaction, and PROMs was achieved in slightly more than half of the patients following secondary patella resurfacing. However, studies lacked standardized objective selection criteria for the procedure and the available data was predominantly retrospective, with high heterogeneity and variation in outcome reporting.

Widening the Operative Corridor-Evaluating the Transcortical Approach to Giant Falcine Meningiomas

BACKGROUND

Giant falcine meningiomas are surgically complex as they are deep in location, concealed by normal brain parenchyma, in close proximity to various neurovascular structures, and frequently involve the falx bilaterally. Although classically accessed using a bifrontal craniotomy and interhemispheric approach, little data exist on alternative operative corridors for these challenging tumors. We evaluated perioperative and long-term outcomes in patients undergoing transcortical resection of giant bilateral falcine meningiomas.

METHODS

From 2013 to 2022, fourteen patients with giant bilateral falcine meningiomas treated via a transcortical approach at our institution were identified. Perioperative and long-term outcomes were evaluated to determine predictors of adverse events. Corticectomy depth was also analyzed to determine if it correlated with increased postoperative seizure rates.

RESULTS

57.1% of cases were WHO grade 2 meningiomas. Average tumor volume was 77.8 ± 46.5 cm3 and near/gross total resection was achieved in 78.6% of patients. No patient developed a venous infarct or had seizures in the 6 months after surgery. Average corticectomy depth was 0.83 ± 0.71 cm and increasing corticectomy depth did not correlate with higher risk of postoperative seizures (P = 0.44). Increasing extent of tumor resection correlated with lower tumor grade (P = 0.011) and only 1 patient required repeat resection during a median follow-period of 24.9 months.

CONCLUSIONS

The transcortical approach is a safe alternative corridor for accessing giant, falcine meningiomas, and postoperative seizures were not found to correlate with increasing corticectomy depth. Further prospective studies are necessary to determine the best approach to these surgically complex lesions.

Open injuries and obesity as emerging risk factors for vascular injury in knee dislocations: A retrospective study

PURPOSE

Knee dislocations (KDs) are rare in orthopaedic trauma but can have devastating effects. Failing to diagnose a concomitant vascular injury can lead to amputation. Different methods are used for the diagnosis of a vascular injury and the best approach is under debate. This study aims to examine the risk factor(s) of vascular injury in patients with KDs, examine variables that differ between obese patients and non-obese patients with KDs, and analyse the modalities used to identify vascular injuries in the KD population.

METHODS

The electronic patient medical record system at a major trauma centre was retrospectively reviewed to identify knee dislocations from 2015 to 2022. These were stratified based on age, gender, BMI, mechanism of injury, vascular injury, non-vascular complications, and laterality. Co-variates were inputted into a univariable regression analysis, followed by a multivariable regression analysis to identify risk factors of vascular injury in patients with knee dislocations. Co-variates were also compared between obese and non-obese patients using two-tailed t-tests for continuous variables and chi-squared test for categorical variables.

RESULTS

Forty patients were identified with a KD, with twenty-eight males and twelve females. The average age was 42.9 years, seventeen patients had a BMI of thirty or over, and eleven patients (27.5%) had a vascular injury. Open injuries (OR: 2.21; 95% CI: 1.19-11.30; p = 0.038) and obesity (OR: 2.66; 95% CI: 1.45-18.69; p = 0.027) are risk factors for vascular injury in patients with knee dislocation. Compared to non-obese patients, obese patients had a higher rate of open injury (p = 0.028), vascular injury (p = 0.017), low-energy injuries (p = 0.014), non-vascular complications (p = 0.017), and amputation (p = 0.036).

CONCLUSION

Open injuries and obesity are risk factors for vascular injury in patients with KD. Compared to non-obese patients, obese patients have low-energy injuries and an increased rate of non-vascular complications, meaning that clinicians could err on the side of caution when investigating vascular injury.

LEVEL OF EVIDENCE

IV.

Clinical Equipoise in the Management of Patients With Femoroacetabular Impingement Syndrome and Concomitant Tönnis Grade 2 Hip Osteoarthritis or Greater: An International Expert-Panel Delphi Study

PURPOSE

To gather global-expert opinion on the management of patients with femoroacetabular impingement syndrome (FAIS) and Tönnis grade 2 hip osteoarthritis (OA) or greater.

METHODS

An internet-based modified Delphi methodology was used via an online platform (Online Surveys) using the CREDES (Conducting and Reporting Delphi Studies) guidelines. The expert panel comprised 27 members from 18 countries: 21 orthopaedic surgeons (78%), 5 physiotherapists (18%), and 1 dual orthopaedic surgeon-sport and exercise medicine physician (4%). Comments and suggestions were collected during each round, and amendments were performed for the subsequent round. Between each pair of rounds, the steering panel provided the experts with a summary of results and amendments. Consensus was set a priori as minimum agreement of 80%.

RESULTS

Complete participation (100%) was achieved in all 4 rounds. A final list of 10 consensus statements was formulated. The experts agreed that there is no single superior management strategy for FAIS with Tönnis grade 2 OA and that Tönnis grade 3 OA and the presence of bilateral cartilage defects (acetabular and femoral) is a contraindication for hip preservation surgery. Nonoperative management should include activity modification and physiotherapy with hip-specific strengthening, lumbo-pelvic mobility training, and core strengthening. There was no consensus on the need for 3-dimensional imaging for initial quantification of joint degeneration.

CONCLUSIONS

There is clinical equipoise in terms of the best management strategy for patients with FAIS and Tönnis grade 2 OA, and therefore, there is an urgent need to perform a randomized controlled trial for this cohort of patients to ascertian the best management strategy.

LEVEL OF EVIDENCE

Level V, expert opinion.

Outcomes of primary Latarjet vs. revision Latarjet after prior surgery for anterior shoulder instability: a systematic review and meta-analysis

BACKGROUND

Latarjet has become an increasingly popular treatment option for recurrent anterior shoulder instability. With the reported complication rates for primary Latarjet surgery, there are concerns about the complications of Latarjet as a revision surgery. It remains unclear if poor results after previous surgical management can be improved with revision Latarjet as well as with primary Latarjet. The aim of this systematic review and meta-analysis is to compare the outcomes of primary Latarjet and revision Latarjet for the treatment of anterior shoulder instability.

METHODS

A systematic search was performed on 3 databases for studies that compared primary Latarjet with revision Latarjet used after failed arthroscopic stabilization or failed free bone block procedures. From the included studies, demographic data, clinical outcome scores, range of motion measurements, and postoperative complications were obtained.

RESULTS

A total of 11 studies were included for data analysis. Compared with the primary Latarjet cohort, revision Latarjet cohorts had a higher infection rate (1.2% vs. 2.6%; RR 0.46, P = .039). The primary Latarjet group showed a greater rate of return to sport (89.7% vs. 80.5%; RR 1.12, P = .41) and less subjective feeling of instability (12.6% vs. 20.9%; RR 0.60, P = .085) compared with the revision Latarjet group; however, this was not statistically significant. There were no significant differences in complication rates, reoperation, recurrence, and range of motion between primary Latarjet and revision Latarjet groups. Clinical outcome scores such as visual analog scale and Rowe scores were not significantly different between the cohorts.

CONCLUSION

Based on the current evidence, primary Latarjet presents reduced infection rates but similar clinical outcome measures, overall complication, and range of motion measurements than revision Latarjet performed after failed prior operative treatment.

Predictors for infection severity for open tibial fractures: major trauma centre perspective

INTRODUCTION

Open diaphyseal tibial fractures are the most common long-bone fractures and require a rapid approach to prevent devastating complications. Current literature reports the outcomes of open tibial fractures. However, there is no robust, up-to-date research on the predictive indicators of infection severity in a large open tibial fracture patient cohort. This study investigated the predictive factors of superficial infections and osteomyelitis in open tibial fractures.

MATERIALS AND METHODS

A retrospective analysis of the tibial fracture database was carried out from 2014 to 2020. Criteria for inclusion was any tibial fracture including tibial plateau, shaft, pilon or ankle, with an open wound at the fracture site. Exclusion criteria included patients with a follow-up period of less than 12 months and who are deceased. A total of 235 patients were included in our study, of which 154 (65.6%), 42 (17.9%), and 39 (16.6%) developed no infection, superficial infection, or osteomyelitis, respectively. Patient demographics, injury characteristics, fracture characteristics, infection status and management details were collected for all patients.

RESULTS

On multivariate modelling, patients with BMI > 30 (OR = 2.078, 95%CI [1.145-6.317], p = 0.025), Gustilo-Anderson (GA) type III (OR = 6.120, 95%CI [1.995-18.767], p = 0.001), longer time to soft tissue cover (p = 0.006) were more likely to develop a superficial infection, and patients with wound contamination (OR = 3.152, 95%CI [1.079-9.207], p = 0.036), GA-3 (OR = 3.387,95%CI [1.103-10.405], p = 0.026), longer to soft tissue cover (p = 0.007) were more likely to develop osteomyelitis. Univariate analysis also determined that risk factors for superficial infection were: BMI > 35 (OR = 6.107, 95%CI [2.283-16.332], p = 0.003) and wound contamination (OR = 2.249, 95%CI [1.015-5.135], p = 0.047); whilst currently smoking (OR = 2.298, 95%CI [1.087-4.856], p = 0.025), polytrauma (OR = 3.212, 95%CI [1.556-6.629], p = 0.001), longer time to definitive fixation (p = 0.023) were for osteomyelitis. However, none of these reached significance in multivariate analysis.

CONCLUSION

Higher GA classification is a significant risk factor for developing superficial infection and osteomyelitis, with a stronger association with osteomyelitis, especially GA 3C fractures. Predictors for superficial infection included BMI and time to soft tissue closure. Time to definitive fixation, time to soft tissue closure, and wound contamination were associated with osteomyelitis.

Using Pre-Clinical Studies to Explore the Potential Clinical Uses of Exosomes Secreted from Induced Pluripotent Stem Cell-Derived Mesenchymal Stem cells

Recent studies of exosomes derived from mesenchymal stem cells (MSCs) have indicated high potential clinical applications in many diseases. However, the limited source of MSCs impedes their clinical research and application. Most recently, induced pluripotent stem cells (iPSCs) have become a promising source of MSCs. Exosome therapy based on iPSC-derived MSCs (iMSCs) is a novel technique with much of its therapeutic potential untapped. Compared to MSCs, iMSCs have proved superior in cell proliferation, immunomodulation, generation of exosomes capable of controlling the microenvironment, and bioactive paracrine factor secretion, while also theoretically eliminating the dependence on immunosuppression drugs. The therapeutic effects of iMSC-derived exosomes are explored in many diseases and are best studied in wound healing, cardiovascular disease, and musculoskeletal pathology. It is pertinent clinicians have a strong understanding of stem cell therapy and the latest advances that will eventually translate into clinical practice. In this review, we discuss the various applications of exosomes derived from iMSCs in clinical medicine.

Popliteal tendon impingement as a cause of pain following total knee arthroplasty: a systematic review

INTRODUCTION

Popliteal tendon impingement (PTI) is an under-recognized cause of persistent pain following total knee arthroplasty (TKA). The purpose of the systematic review was to summarize and outline successful strategies in the diagnosis and management of PTI.

METHODS

A systematic review following the PRISMA guidelines was performed for four databases: MEDLINE (Pubmed), Ovid EMBASE, Web of Science, and Cochrane Database. It was registered in the International Prospective Register for Systematic Reviews and Meta-analysis (PROSPERO) under the registration number: CRD42023398723. The risk of bias assessment was performed using the criteria of the methodological index for non-randomized studies (MINORS).

RESULTS

A total of 8 studies were included. There were 2 retrospective case series and 6 case reports. The follow-up ranged from 6 to 30 months. Two studies described PTI as an intraoperative phenomenon during TKA with "snapping"; whilst 6 studies described indications and outcomes for arthroscopic tenotomy for PTI following TKA. In making the diagnosis, there was concurrence that the posterolateral pain should be focal and that dynamic ultrasonography and diagnostic injection play an important role. Two specific clinical tests have been described. There was no consistency regarding the need for imaging. There were no reports of instability following popliteal tendon tenotomy or other complications.

CONCLUSION

PTI should be suspected as a cause for persistent focal pain at the posterolateral knee following TKA. The diagnosis can be suspected on imaging and should be confirmed with dynamic ultrasonography and an ultrasound-guided diagnostic injection. An arthroscopic complete tenotomy of the tendon can reliably alleviate pain and relies on correct diagnosis. There is no evidence for clinically relevant negative biomechanical consequences following tenotomy.

LEVEL OF EVIDENCE

Systematic Review of Level IV and V studies.

Outcomes of arthroscopy of the hip for femoroacetabular impingement based on intraoperative assessment using the Outerbridge classification

Aims

Hip arthroscopy (HA) has become the treatment of choice for femoroacetabular impingement (FAI). However, less favourable outcomes following arthroscopic surgery are expected in patients with severe chondral lesions. The aim of this study was to assess the outcomes of HA in patients with FAI and associated chondral lesions, classified according to the Outerbridge system.

Methods

A systematic search was performed on four databases. Studies which involved HA as the primary management of FAI and reported on chondral lesions as classified according to the Outerbridge classification were included. The study was registered on PROSPERO. Demographic data, patient-reported outcome measures (PROMs), complications, and rates of conversion to total hip arthroplasty (THA) were collected.

Results

A total of 24 studies were included with a total of 3,198 patients (3,233 hips). Patients had significantly less improvement in PROMs if they had Outerbridge grade III and IV lesions (p = 0.012). Compared with microfracture, autologous matrix-induced chondrogenesis (AMIC) resulted in significantly reduced rates of conversion to THA (p = 0.042) and of revision arthroscopy (p = 0.038). Chondral repair procedures in these patients also did not significantly reduce the rates of conversion to THA (p = 0.931), or of revision arthroscopy (p = 0.218). However, compared with microfracture, AMIC significantly reduced the rates of conversion to THA (p = 0.001) and of revision arthroscopy (p = 0.011) in these patients. Those with Outerbridge grade III and IV lesions also had significantly increased rates of conversion to THA (p = 0.029) and of revision arthroscopy (p = 0.023) if they had associated lesions of the acetabulum and femoral head. Those who underwent labral debridement had a significantly increased rate of conversion to THA compared with those who underwent labral repair (p = 0.015).

Conclusion

There is universal improvement in PROMs following HA in patients with FAI and associated chondral lesions. However, those with Outerbridge grade III and IV lesions had significantly less improvement in PROMs and a significantly increased rate of conversion to THA than those with Outerbridge grade I and II. This suggests that the outcome of HA in patients with FAI and severe articular cartilage damage may not be favourable.

Algorithm for evaluating ophthalmic artery pseudo-occlusion during intra-arterial chemotherapy for retinoblastoma

BACKGROUND AND IMPORTANCE

Intra-arterial chemotherapy infusion for retinoblastoma is typically performed via selective catheterization of the ophthalmic artery. Anastomoses between the external carotid and the ophthalmic arteries have also been utilized when the ophthalmic artery cannot be catheterized directly. However, these are not present in every patient.

CLINICAL PRESENTATION

A 10-month-old boy presented with bilateral retinoblastoma and underwent one round of intra-arterial chemotherapy (IAC) via direct catheterization of the ophthalmic arteries. Combined with adjuvant laser therapy, they experienced symptomatic improvement and tumour regression. However, during subsequent treatment sessions both ophthalmic arteries did not have anterograde flow and attempts to catheterize their origin were unsuccessful. Unfortunately, no targetable anastomoses between the external carotid and ophthalmic arteries were identified for drug delivery. Due to the patient's anatomy, balloon occlusion of the ECA was felt to be unsafe. As a salvage technique, a balloon was inflated in the left internal carotid artery (ICA) distal to the ophthalmic take-off to redirect flow into the ophthalmic. Repeat angiography with the distal ICA occluded showed improved flow into the ipsilateral ophthalmic artery. IAC was then successfully delivered through the left ICA.

CONCLUSION

This case illustrates the importance of utilizing creative endovascular techniques for targeted intra-arterial drug delivery when other conventional measures fail as these patients often have limited, and potentially higher risk, therapeutic alternatives.

Genome-wide gene expression responses to experimental manipulation of Saccharomyces cerevisiae repressor activator protein 1 (Rap1) expression level

Precise regulation of transcription in gene expression is critical for all aspects of normal organism form, fitness, and function and even minor alterations in the level, location, and timing of gene expression can result in phenotypic variation within and between species including evolutionary innovations and human disease states. Eukaryotic transcription is regulated by a complex interplay of multiple factors working both at a physical and molecular levels influencing this process. In Saccharomyces cerevisiae, the TF with the greatest number of putative regulatory targets is the essential gene Repressor Activator Protein 1 (RAP1). While much is known about the roles of Rap1 in gene regulation and numerous cellular processes, the response of Rap1 target genes to systematic titration of RAP1 expression level remains unknown. To fill this knowledge gap, we used a strain with a tetracycline-titratable promoter replacing wild-type regulatory sequences of RAP1 to systematically reduce the expression level of RAP1 and followed this with RNA sequencing (RNA-seq) to measure genome-wide gene expression responses. Previous research indicated that Rap1 plays a significant regulatory role in particular groups of genes including telomere-proximal genes, homothallic mating (HM) loci, glycolytic genes, DNA repair genes, and ribosomal protein genes; therefore, we focused our analyses on these groups and downstream targets to determine how they respond to reductions in RAP1 expression level. Overall, despite being known as both an activator and as a repressor of its target genes, we found that Rap1 acts as an activator for more target genes than as a repressor. Additionally, we found that Rap1 functions as an activator of ribosomal protein genes and a repressor of the silent mating locus genes consistent with predictions from the literature. Unexpectedly, we found that Rap1 functions as a repressor of glycolytic enzyme genes contrary to prior reports of it having the opposite effect. We also compared the expression of RAP1 to five different genes related to DNA repair pathway and found that decreasing RAP1 downregulated four of those five genes. Finally, we found no effect of RAP1 depletion on telomere-proximal genes despite its functioning to silence telomeric repeat-containing RNAs. Together our results enrich our understanding of this important transcriptional regulator. The graphical abstract is provided as a supplementary fig. (S-Fig 1).

Outcomes of Acute versus Delayed Reverse Shoulder Arthroplasty for Proximal Humerus Fractures in the Elderly: A Systematic Review and Meta-Analysis

INTRODUCTION

Reverse shoulder arthroplasty (RSA) has become an increasingly popular treatment option for proximal humerus fractures (PHFs) in the elderly. There is however contradictory evidence on the impact of timing of RSA on patient outcomes. It remains unclear if poor results after initial non-surgical or surgical management can be improved with delayed RSA. The aim of this systematic review and meta-analysis is to compare the outcomes of acute RSA and delayed RSA for the treatment of PHFs in the elderly.

METHODS

A systematic search was performed on four databases for studies that compared acute RSA with RSA used after prior non-operative or operative treatment. Studies with a mean cohort age <65 years old were excluded. Demographical data, clinical outcome scores, range of motion measurements, and postoperative complications were collected from included studies.

RESULTS

Sixteen studies were included for data analysis. Compared with delayed RSA cohorts, acute RSA cohorts had higher forward flexion (124.3^o vs 114.9^o; p=0.019), external rotation (24.7^o vs 20.2^o; p=0.041), and abduction (113.2^o vs 99.8^o; p=0.03). Compared to RSA after conservative management, acute RSA had greater external rotation (29.9^o vs 21.4^o; p=0.043). The acute RSA cohort had significantly higher ASES (76.4 vs 68.2; p=0.025) and Constant-Murley scores (65.6 vs 57.3; p=0.002) compared to the delayed RSA cohort. Subgroup analyses showed significantly greater Constant-Murley (64.9 vs 56.9; p=0.020) and SST scores (8.8 vs 6.8; p=0.031) with acute RSA compared to RSA after conservative treatment. ASES score was higher in the acute RSA cohort compared to RSA after open reduction internal fixation (ORIF) (77.9 vs 63.5; p=0.008). The overall complication rate per 100 patient-years was 11.7 for the acute RSA cohort, and 18.5 for the delayed RSA cohort (RR: 0.55; p=0.015).

CONCLUSION

Based on the current evidence, acute RSA presents better clinical outcome measures and range of motion measurements, with decreased complication rates than RSA performed after prior non-operative or operative treatment.

Abstract 1130: A phase 1 dose escalation study of GCC19CART - a novel CoupledCAR therapy for subjects with metastatic colorectal cancer

Background: Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable clinical efficacy in hematologic malignancies but limited success in solid tumors. GCC19CART, the first clinical candidate from the CoupledCAR solid tumor platform, is designed to overcome the limitations of conventional CAR T-cells in solid tumor malignancies by pairing solid tumor CAR T-cells with CD19 targeting CAR T-cells to amplify proliferation and activation of the solid tumor CAR T component. GCC19CART targets guanylate cyclase-C (GCC) which is expressed in the metastatic lesions of 70%-80% of subjects with colorectal cancers. A Phase 1 investigator-initiated clinical trial is underway in China for patients with relapsed or refractory metastatic colorectal cancer who have received at least 2 prior lines of therapy. Based on a data cutoff on October 20, 2022 21 subjects have been enrolled in 2 dose escalation groups at 5 hospitals in China.

Methods: Subjects are screened for GCC expression by immunohistochemistry. Eligible subjects undergo leukapheresis, a single dose of lymphodepleting chemotherapy (fludarabine 30mg/m2 and cyclophosphamide 300mg/m2) 3 days prior to infusion, and then administration of a single infusion of GCC19CART at one of two preassigned doses: 1 × 106 or 2 × 106 CAR T-cells/kg. Endpoints are safety and preliminary evidence of efficacy as determined by CT or PET/CT per RECIST 1.1 or PERCIST 1.0. All responses were confirmed by an independent third-party imaging contract research organization (CRO).

Results: 13 subjects have been enrolled to dose level 1 (1 × 106 cells/kg) and 8 subjects have been enrolled to dose level 2 (2 × 106 cells/kg). The most common adverse events were cytokine release syndrome (CRS) in 21/21 subjects (Grade 1 19/21 (90.48%) or Grade 2 2/21 (9.52%)) and diarrhea in 21/21 subjects (Grade 1 6/21 (28.57%) Grade 2 5/21 (23.81%) Grade 3 9/21 (42.86%) or Grade 4 1/21 (4.76%)). Neurotoxicity was observed in 2/21 (9.52%) subjects at Grade 3 or 4 and resolved with corticosteroids. The combined overall response rate (ORR) for both dose levels was 28.6% (6/21). For dose level 1, the overall response rate (ORR) per RECIST 1.1 was 15.4% (2/13). Two subjects demonstrated a partial response (PR) while 3 additional subjects had partial metabolic response (PMR) on PET/CT with stable disease (SD) or progressive disease (PD) per RECIST 1.1. For dose level 2, The ORR per RECIST 1.1 was 50% (4/8). 4 subjects demonstrated a PR (3 at month 1, 1 at month 3 after being SD at month 1) and 2 additional subjects had PMR on PET/CT with SD per RECIST 1.1.

Conclusions: preliminary data show that GCC19CART has meaningful dose dependent clinical activity and an acceptable safety profile in relapsed or refractory metastatic colorectal cancer. This trial is ongoing and updated data will be presented. A Phase 1 trial of GCC19CART in the US under a cleared IND is expected to enroll patients from mid-2022.

Citation Format: Naifei Chen, Chengfei Pu, Lingling Zhao, Ning Li, Chang Wang, Yusheng Huang, Suxia Luo, Xun Li, Zhenzhou Yang, Jun Bie, Ruihong Zhu, Xi Huang, Haiyang Tang, Tingting Liang, Yizhuo Wang, Beibei Jia, Dongqi Chen, Zhao Wu, Yongping Song, Victor Lu, Lei Xiao, Jiuwei Cui. A phase 1 dose escalation study of GCC19CART - a novel CoupledCAR therapy for subjects with metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1130.

The impact of extended reality on surgery: a scoping review

PURPOSE

Extended reality (XR) is defined as a spectrum of technologies that range from purely virtual environments to enhanced real-world environments. In the past two decades, XR-assisted surgery has seen an increase in its use and also in research and development. This scoping review aims to map out the historical trends in these technologies and their future prospects, with an emphasis on the reported outcomes and ethical considerations on the use of these technologies.

METHODS

A systematic search of PubMed, Scopus, and Embase for literature related to XR-assisted surgery and telesurgery was performed using Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) guidelines. Primary studies, peer-reviewed articles that described procedures performed by surgeons on human subjects and cadavers, as well as studies describing general surgical education, were included. Non-surgical procedures, bedside procedures, veterinary procedures, procedures performed by medical students, and review articles were excluded. Studies were classified into the following categories: impact on surgery (pre-operative planning and intra-operative navigation/guidance), impact on the patient (pain and anxiety), and impact on the surgeon (surgical training and surgeon confidence).

RESULTS

One hundred and sixty-eight studies were included for analysis. Thirty-one studies investigated the use of XR for pre-operative planning concluded that virtual reality (VR) enhanced the surgeon's spatial awareness of important anatomical landmarks. This leads to shorter operating sessions and decreases surgical insult. Forty-nine studies explored the use of XR for intra-operative planning. They noted that augmented reality (AR) headsets highlight key landmarks, as well as important structures to avoid, which lowers the chance of accidental surgical trauma. Eleven studies investigated patients' pain and noted that VR is able to generate a meditative state. This is beneficial for patients, as it reduces the need for analgesics. Ten studies commented on patient anxiety, suggesting that VR is unsuccessful at altering patients' physiological parameters such as mean arterial blood pressure or cortisol levels. Sixty studies investigated surgical training whilst seven studies suggested that the use of XR-assisted technology increased surgeon confidence.

CONCLUSION

The growth of XR-assisted surgery is driven by advances in hardware and software. Whilst augmented virtuality and mixed reality are underexplored, the use of VR is growing especially in the fields of surgical training and pre-operative planning. Real-time intra-operative guidance is key for surgical precision, which is being supplemented with AR technology. XR-assisted surgery is likely to undertake a greater role in the near future, given the effect of COVID-19 limiting physical presence and the increasing complexity of surgical procedures.

The clinical characteristics and management of paediatric pelvic fractures: a changing landscape based on skeletal maturity

INTRODUCTION

Paediatric pelvic fractures (PPFs) are uncommon but signify serious trauma. A comprehensive multidisciplinary approach is needed due to a high number of associated injuries. This study aims to retrospectively analyse PPFs over a 5-year period and evaluate how advancing skeletal maturity changes fracture patterns and management plans.

METHODS

The trauma database was retrospectively reviewed for pelvic fractures in patients aged ≤ 18 years. Radiographs and CT scans were used to classify pelvic injuries according to the modified Torode classification and determine the status of the triradiate cartilage (open: skeletally immature; closed: skeletally mature). Data collected also included the mechanism of injury, clinical and functional outcomes, and associated injuries. Logistic regression analysis was performed to identify risk factors for associated abdominal injuries.

RESULTS

65 PPFs (2.8% of paediatric trauma admissions during the study period) were classified as type I (3.1%), type II (7.7%), type IIIa (32.3%), type IIIb (38.5%), type IV (18.5%) according to the modified Torode classification. The mean age was 13.41 ± 3.82. Skeletally immature children were more likely to be hit by a motor vehicle as a pedestrian (p < 0.001), be intubated (p = 0.009), acquire Torode type II (p = 0.047) and rami fractures (p = 0.037), and receive chest (p = 0.005) and head injuries (p = 0.046). Skeletally immature children were also less likely to acquire Torode type IV fractures (p = 0.018), receive surgical treatment for their pelvic injuries (p = 0.036), and had a faster time to full weight bearing (p = 0.013). Pelvis AIS score ≥ 4 (OR 5.3; 95% CI 1.3-22.6; p = 0.023) and a pedestrian accident (OR 4.9; 95% CI 1.2-20.7; p = 0.030) were risk factors for associated abdominal injuries. There was a strong association between a higher pelvic fracture grade and the proportion of patients with closed triradiate cartilage (p = 0.036), hospital length of stay (p = 0.034), mean pelvic AIS score (p = 0.039), a pelvis AIS score of ≥ 4 (p = 0.022), mean ISS (p = 0.003), an ISS score between 25 and 75 (p = 0.004), average time to FWB (p = 0.001), requirement of blood products (p = 0.015), and a motor vehicle accident (p = 0.037).

CONCLUSION

PPFs occurring in skeletally mature and immature patients are significantly different in terms of mechanism of injury, fracture severity, fracture pattern, and management strategy. There is a high rate of associated injuries, necessitating an integrated multidisciplinary approach in paediatric trauma centres.

Ankle fusion with tibiotalocalcaneal retrograde nail for fragility ankle fractures: outcomes at a major trauma centre

PURPOSE

Fragility ankles fractures in the geriatric population are challenging to manage, due to fracture instability, soft tissue compromise, and patient co-morbidities. Traditional management options include open reduction internal fixation, or conservative treatment, both of which are fraught with high complication rates. We aimed to present functional outcomes of elderly patients with fragility ankle fractures treated with retrograde ankle fusion nails.

METHODS

A retrospective observational study was performed on patients who underwent intramedullary nailing with a tibiotalocalcaneal nail. Twenty patients met the inclusion criteria of being over sixty and having multiple co-morbidities. Patient demographics, AO/OTA fracture classification, intra-operative and post-operative complications, time to mobilisation and union, AOFAS and Olerud-Molander scores, and patient mobility were recorded.

RESULTS

There were seven males and thirteen females, with a mean age of 77.82 years old, five of whom are type 2 diabetics. Thirteen patients returned to their pre-operative mobility state, and the average Charlson Co-morbidity Index (CCI) was 5.05. Patients with a low CCI are more likely to return to pre-operative mobility status (p = 0.16; OR = 4.00). All patients achieved radiographical union, taking on average between 92.5 days and 144.6 days. The mean post-operative AOFAS and Olerud-Molander scores were 53.0 and 50.9, respectively. There were four cases of superficial infection, four cases of broken or loose distal locking screws. There were no deep infections, periprosthetic fractures, nail breakages, or non-unions.

CONCLUSION

Tibiotalocalcaneal nailing is an effective and safe option for managing unstable ankle fractures in the elderly. This technique leads to lower complication rates and earlier mobilisation than traditional fixation methods.

No evidence exists on outcomes of non-operative management in patients with femoroacetabular impingement and concomitant Tönnis Grade 2 or more hip osteoarthritis: a scoping review

PURPOSE

The purpose of this scoping review was to assess the outcomes of all the non-operative modalities of management for femoroacetabular impingement (FAI) and concomitant osteoarthritis (OA) Tönnis Grade 2 or more.

METHODS

A systematic search of PubMed was performed from inception to December 1st 2021 for literature on outcomes of non-operative management strategies for young adults with symptomatic FAI using the PRISMA Extension for Scoping Reviews guidelines. Cohorts investigating FAI and concomitant hip OA Tönnis Grade 2 or more were considered eligible. Studies not written in English or German, below level 4 evidence, and reviews were excluded. A secondary analysis for FAI without OA stratification was conducted after the initial screening to allow identification of available non-operative interventions.

RESULTS

No study reported outcomes separately for non-operative management of FAI with Tönnis Grade 2 OA or more and as such, did not fulfil the inclusion criteria. A secondary analysis included 24 studies that reported on outcomes for non-operative interventions for FAI irrespective of the degree of degeneration. Three studies investigated the efficacy of hyaluronic acid injection, 5 reports investigated corticosteroid injections, 2 studies evaluated the outcomes of hip bracing and 16 studies included a physiotherapy programme. Associations between the aforementioned interventions were analysed. There is level I evidence supporting the efficacy of activity modification and hip-specific physiotherapy for FAI and mild OA. Core-strengthening exercises are prevalent amongst successful regimens in the literature. Contradictory evidence questions the efficacy of hip bracing even for short-term outcomes. Corticosteroid injections have mostly failed in intention-to treat analyses but may be valuable in delaying the need for surgery; further studies are warranted. Reports on outcomes following hyaluronic acid injections are contradictory.

CONCLUSION

No evidence exists on outcomes following non-operative management of FAI with concomitant Tönnis Grade 2 or more OA of the hip. Further studies are required and should explore the non-operative interventions that were employed for FAI and milder OA. There is strong evidence for a hip-specific physiotherapy program including activity modification and core strengthening exercises. Adjunct interventions such as corticosteroid injections and NSAID consumption may be valuable in delaying the need for surgery.

LEVEL OF EVIDENCE

Level IV.

SURG-15. MINIMALLY INVASIVE PREFRONTAL APPROACH FOR GLIOMAS: TECHNICAL DESCRIPTION AND ASSOCIATED COMPLICATIONS

INTRODUCTION

Classical prefrontal approaches exposed the lateral surface of the frontal lobe. Minimally invasive (MI) approaches achieved to reduce soft tissue damage and craniotomy size without affecting tumor resection grade. This is associated with shorter hospital stays and faster return to preoperative daily activities.

OBJECTIVE

To describe the MI prefrontal glioma resection technique developed in our department and to analyze our surgical results.

METHODS

We performed a retrospective review of patients who underwent prefrontal lobe glioma (WHO grade II-IV) resection using an MI approach in 2016-2021 at the University of Miami Hospital. Re-surgery, biopsy-only patients, multicentric tumors, and patients with less than four months of follow-up were excluded. Demographic and clinical data were collected. A 4-5 cm linear incision is done, starting at 1 cm lateral to the sagittal suture and extending towards the superior temporal line. An ellipsoidal-shaped mini-craniotomy is performed.

RESULTS

Thirty-four patients were included. The mean age was 50.2 years old, with 20 male subjects. Twenty-two patients had high-grade gliomas (HGG) and 12 patients had low-grade gliomas (LGG). On average, patients were discharged 1.97 days after surgery. The mean craniotomy area was 15,5 cm2 (7-43 cm2). The mean tumor volume was 64,5 cm2 ( 9 -165.8 cm2). Two wound infections and one case of aseptic meningitis were observed in patients with craniotomies &gt; 15 cm2, while the group with craniotomies &lt; 15 cm2 had no perioperative complications. In the HGG group, a supramaximal resection (SMR) was achieved in 8 patients, 9 HGG patients had gross total resection (GTR) or near-total resection (NTR), and 5 patients had subtotal resection (STR). In the LGG, GTR was achieved in 10 patients and STR in 2 patients.

CONCLUSION

MI prefrontal approach for frontal gliomas is safe and feasible with minor complications, short hospital stay, and without sacrificing tumor resection volume.

QLTI-13. FEASIBILITY OF SAMEDAY DISCHARGE AFTER BRAIN TUMOR RESECTION: A PROSPECTIVE QUALITY INTERVENTION STUDY

INTRODUCTION

Cranial neurosurgery confers psychological stress, as well as the stress of being in the hospital rather than in one’s preferred surroundings. Compared with inpatient admissions, same-day discharges reduce patient exposure to nosocomial infection, thromboembolic complications, and medical error. Also, it reduces costs to the health care system.

OBJECTIVE

To report the results of a pilot study that prospectively evaluated for the first time in a United States hospital, the outcomes of patients that underwent brain tumor surgery and are discharged home the same day as surgery.

METHODS

A quality intervention study including patients who underwent outpatient craniotomy for brain tumors by a single neurosurgeon (R.J.K) at the University of Miami from August 2020 to August 2021 was performed. Patients included were between 16 to 85 years old, with a Karnofsky Performance Status score of ≥ 70, and with supratentorial tumors with a maximum diameter of 4 cm. Complete demographic and clinical data were collected prospectively for each patient. In all patients, the minimum observation period was 6 h after surgery.

RESULTS

37 of 334 patients met the inclusion criteria for the outpatient protocol. Thirty-two patients were discharged on the same day as surgery. Five patients (14%) were considered eligible for outpatient surgery but were ultimately admitted to the hospital postoperatively and were discharged after overnight observation. No postoperative complications were noted at two-week follow-up.

CONCLUSION

With appropriate selection and postoperative monitoring, same-day discharge can be considered a safe and feasible option for certain craniotomy cases. Establishing a multidisciplinary team of physicians, nurses, radiologists, and physical therapists is critical to achieving this aim. Physicians should have a low threshold to admit a patient with concerning exam findings, complications, or complicated past medical history

QLTI-16. ENHANCED RECOVERY AFTER LASER ABLATION SURGERY: A PRELIMINARY ANALYSIS OF A NOVEL PROGRAM

INTRODUCTION

The concept of enhanced recovery after surgery (ERAS) due to standardized interventions has been gaining more relevance within neurosurgery. Advances were made both in protocols for spine and cranial surgery. These experiences described many benefits such as less psychological stress, reduction in hospitalization days, and lower hospital costs, without increasing the incidence of complications. However, no experience has described to date the applicability of an ERAS program for laser ablation thermal therapy (LITT).

OBJECTIVE

To describe our initial experience with the first enhanced recovery program reported for laser ablation for brain tumors. Secondly, to summarize the perioperative clinical outcomes of ERAS applied to LITT.

METHODS

We performed a retrospective analysis of all adult patients who underwent LITT for oncological lesions from 2013 to 2021. A multidisciplinary program was created by protocolizing interventions carried out along the path of the patient's hospitalization. Each recommendation was individually assessed for its appropriateness for enhancing recovery and for its validity with a focused literature review process.

RESULTS

A total of 184 patients were included, with a mean age of 60.7 ± 13.5 years, 35% males. 167 tumors were located in the supratentorial compartment, and 17 were infratentorial; the mean tumor diameter was 1.84 ± 1.04 cm. Among the pathologies treated 50.0% were metastasis, and 36.9% were glioblastomas. The mean postoperative day discharge was 1.2 ± 0.8 days. The readmission rate due to surgical complications within 30 days of surgery was 2.7%. These readmission rates fall into what is expected according to published literature without an ERAS program and longer hospital admissions. One death was recorded in the perioperative period.

CONCLUSION

Clinical interventions that could constitute an ERAS program are feasible in laser ablation of brain tumors. This study could be useful as a preliminary framework for the development of future guidelines.

SURG-28. ADULT MIDLINE GLIOMAS TREATED WITH LASER INTERSTITIAL THERMAL THERAPY (LITT): OUR COMPARATIVE EXPERIENCE WITH NEEDLE BIOPSY

INTRODUCTION

Adult midline gliomas are rare entities, with a scarcity of available clinical data. These patients have variable courses, with limited evidence to predict outcomes. Emerging evidence suggests that biomolecular profiles may play a significant role in outcomes, so tissue diagnosis is a key component of management. However, the role of cytoreductive therapy, such as Laser Interstitial Thermal Therapy (LITT) remains unknown. To date, only a few studies have described the use of MRI-guided LITT for managing midline gliomas.

OBJECTIVE

To present a retrospective analysis of a single-center two-surgeon experience treating adult midline gliomas with either biopsy/LITT or biopsy alone.

METHODS

Patients with midline intraxial tumors surgically treated at our tertiary care referral center were identified using our established database. Twenty-one patients managed either with biopsy/LITT or needle biopsy from 2015 to 2021 were included. Demographics and clinical records including, among others, length of hospital stay, preoperative lesion size, ablation volume, perioperative complications, adjuvant treatment, and stratified overall survival (OS) were collected.

RESULTS

The two cohorts were composed of 7 patients who underwent LITT, and 14 biopsies. The mean age was 60.95y (25-82). The average tumor volumes were 16.99 cm3 and 15.41 cm3 for LITT and biopsy, respectively. No post-surgical complications were found in the LITT group, one patient had a postsurgical hemorrhage after biopsy. The mean OS was 20.28 ± 9.63 months in the LITT group, which was greater but not statistically significant than in the biopsy group (11.05 ± 4.45 months) (p = 0.605).

CONCLUSION

Our results show that LITT is as safe as needle biopsy for the treatment of adult midline gliomas, and may offer a survival benefit given its cytoreductive properties.

Retrograde tibiotalocalcaneal nailing for the treatment of acute ankle fractures in the elderly: a systematic review and meta-analysis

Introduction

Methods

Results

Conclusion

111 Adipose Tissue-Derived Mesenchymal Stem Cells as a Potential Restorative Treatment for Cartilage Defects: A PRISMA Review and Meta-Analysis

Aim

Joint damage through trauma or degeneration causes cartilage defects, leading to osteoarthritis (OA). Current therapies relieve symptoms or replaces damaged joint, which is costly and fraught with complications. Mesenchymal stem cells (MSCs) have immunomodulatory properties and low immunogenicity, making them a novel avenue for research for OA treatment. This systematic review investigates whether adipose derived MSC (AMSCs) can treat cartilage defects.

Method

A systematic search was performed on MEDLINE, EMBASE, Cochrane Library, Scopus, Web of Science. Clinical, imaging, functional outcomes were extracted from nineteen included studies. Inclusion criteria was studies conducted on human populations that compared effects of AMSCs on cartilage regeneration to non-exposed controls. Studies conducted on animals, ex vivo studies, in vitro studies were excluded.

Results

Nine studies reported improved Visual Analogue Scale (VAS) scores (mean difference -3.30; 95% CI:-3.72,-2.89; p&lt;0.001). Eight studies reported improved Knee injury and Osteoarthritis Outcome Score (KOOS) in five subscales. Pooled analysis of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in seven studies revealed an improvement (mean difference -25.52; 95% CI:-30.93,-20.10; p&lt;0.001). Cartilage regeneration was assessed using Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. All studies reported improved regeneration, with a pooled end-point score of 68.12 (95% CI:62.18–74.05; p&lt;0.001).

Conclusions

AMSCs are effective therapeutic agents for cartilage defects. We recommend researchers to determine roles of biochemical components that facilitate AMSC-mediated cartilage repair. Establishing the most efficient methods for MSC extraction, culture, delivery, and performing studies with long follow-up times enable future research to provide evidence needed to bring AMSC-based therapies into the market.

180 Retrograde Hindfoot Nailing for the Treatment of Acute Ankle Fractures in the Elderly - a Systematic Review and Meta-Analysis

Aim

Fragility ankle fractures are traditionally managed conservatively or with open reduction internal fixation (ORIF). Tibiotalocalcaneal (TTC) nailing is an alternative option for the geriatric patient. This meta-analysis provides the most detailed analysis of hindfoot nailing for fragility ankle fractures.

Method

A systematic search was performed on MEDLINE, EMBASE, Cochrane Library, Scopus, Web of Science, identifying fourteen studies for inclusion. Studies including patients over 60 with a fragility ankle fracture, treated with TTC nail were included. Patients with a previous fracture of the ipsilateral limb, fibular nails, and pathological fractures were excluded.

Meta-regression analyses were performed to explore sources of heterogeneity, and publication bias was assessed using Egger's test.

Results

312 ankle fractures were included. The mean age was 77.3 (32–101) years. 26.9% were male, and 41.9% were diabetics. The pooled proportion of superficial infection, deep infection, implant failure, malunion, and all-cause mortality was 0.10 (95%CI:0.06–0.16; I2=44%), 0.08 (95%CI:0.06–0.11, I2=0%), 0.11 (95%CI:0.07–0.15,I2=0%), 0.11 (95%CI:0.06–0.18; I2=51%), and 0.27 (95%CI:0.20–0.34; I2=11%), respectively. The pooled mean post-operative OMAS score was 54.07 (95%CI:48.98–59.16; I2=85%). The best-fitting meta-regression model included age and percentage of male patients as covariates (p=0.0263), and were inversely correlated with higher OMAS scores. Egger's test (p=0.56) showed no significant publication bias.

Conclusions

TTC nailing is an adequate alternative option for fragility ankle fracture management. However, current evidence includes mainly case series with inconsistent outcome measures reported and post-operative rehabilitation protocols. Prospective RCTs with long follow-up times and large cohort sizes are needed to clearly guide the use of TTC nailing for ankle fractures.

893 Predictors for Infection Severity in Open Tibial Fractures

Aim

Open tibial fractures can be difficult to manage - many factors could affect treatment and outcome, including being complicated by infection. We present a cohort of 244 patients and analyse which factors are significantly associated with infection outcome.

Method

Open tibia fractures treated at a major trauma centre between 2015–2021 were included.

Infection status was categorized into no infection, superficial infection, osteomyelitis. Data collected were Age, mode of injury, polytrauma, fibula status, Gustilo-Anderson (GA) classification, wound contamination, time to first procedure. time to definitive plastics procedure, time to definitive fixation, type of definitive fixation, smoking/diabetic status, and BMI.

Multicollinearity was calculated, with highly correlated factors removed. Multinomial logistic regression was performed. Chi-Squared test, with Post-Hoc Bonferroni correction was performed for complex categorical factors.

Results

244 patients were included. Polytrauma and fibula status, and type of definitive fixation were excluded from the multivariate model due to strong multicollinearity. Compared to non-infected outcome, patients with superficial infection had higher BMI (p&lt;0.01), higher GA grade (p&lt;0.01), and osteomyelitis patients had longer time to definitive fixation (p=0.049) and longer time to definitive plastics procedure (p=0.013), higher GA grade, and wound contamination.

Post-hoc analysis showed “no infection” was positively associated with GA-I (p=0.029) and GA-II (p&lt;0.01), and negatively associated with GA-IIIC (p&lt;0.01). Osteomyelitis was positively associated with GA-IIIc (p&lt;0.01)

Conclusions

This study investigated associations between injury and presentation factors that may have been associated with infection. We suggest clinicians should give extra consideration to the factors highlighted during management and take preventative measures to mitigate the infection risk.

114 Bone Transport Using the Monorail External Fixator Over an Intramedullary Nail for Post-Traumatic Femoral Defects

Aim

The management of limb-length discrepancy secondary to traumatic bone loss poses a unique challenge for surgeons. The Ilizarov technique is popular but is associated with long external fixator time and many complications. This retrospective study assessed outcomes of post-traumatic femoral defects managed by monorail external fixation over an intramedullary nail.

Method

Eight patients were included from over a four-year period with post-traumatic femoral defects, that underwent treatment with monorail fixator-assisted intramedullary nailing. Mean follow-up time was 232.83 weeks. Five were open fractures (Gustilo-Anderson type 3A:n=4, 3B:n=1), one had closed fracture. Average bone defect size was 8cm. Primary outcomes were lengthening index, consolidation time and index, external fixator index. Secondary outcomes were time to full weight bearing(FWB), time to union, complications. Patient reported outcome measures including EQ-5D-5L, SF-36, Oxford knee scores(OKS), Oxford hip scores(OHS) were recorded after recovery.

Results

Average consolidation time and index were 11.35months and 1.24months/cm, respectively. Mean lengthening and external fixator index were 20.2days/cm and 23.88days/cm, respectively. On average, patients achieved FWB and bone union 56.25 weeks and 68.83 weeks after bone transport initiation, respectively. Two patients had docking site non-union, treated by reamed intramedullary exchange nailing. Two patients had osteomyelitis. EQ-5D-5L and EQ-VAS scores were compared to UK population norms (p=0.104, p=0.238, respectively). Average OKS was 32.17 and OHS was 34.00.

Conclusions

Monorail external fixation over an intramedullary nail is an effective option for post-traumatic femoral defects, reducing external fixator time, lowering complication rate, returning patients’ quality of life to a level comparable with the normal population.

245 Ankle Fusion with Tibiotalocalcaneal Retrograde Nail for Fragility Ankle Fractures: Outcomes at a Major Trauma Centre

Aim

Fragility ankles fractures in the geriatric population are challenging to manage, due to fracture instability, soft tissue compromise, and patient co-morbidities. Traditional management options include open reduction internal fixation, or conservative treatment, both of which are fraught with high complication rates. We aimed to present functional outcomes of elderly patients with fragility ankle fractures treated with retrograde ankle fusion nails.

Method

171 patients received a tibiotalocalcaneal nail over a six-year period, but only twenty met the inclusion criteria of being over sixty and having poor bone stock. Primary outcome was mortality risk from co-morbidities according to Charlson co-morbidity index (CCI), and patients’ post-operative mobility status compared to pre-operative mobility. Secondary outcomes include intra-operative and post-operative complications, six-month mortality rate, time to mobilisation and union.

Results

Mean age was 77.82 years old. The average CCI was 5.05. Thirteen patients returned to their pre-operative mobility state. Patients with low CCI are more likely to return to pre-operative mobility status (p=0.16;OR=4.00).

Average time to bone union and mobilisation were 92.5 days and 7.63 days, respectively. Mean post-operative AOFAS ankle-hindfoot and Olerud-Molander scores were 53.0 and 50.9, respectively. There were four cases of superficial infection. Patients with high CCI were more likely to acquire superficial infections (p=0.264,OR=3.857). There were no deep infections, periprosthetic fractures, nail breakages, non-unions. Average follow-up time was 499.3 days.

Conclusions

Tibiotalocalcaneal nailing is an effective and safe option for managing fragility ankle fractures in the elderly. This technique leads to lower complication rates and earlier mobilisation than traditional fixation methods.

SP5.2.2 Our Management of Distal Femoral Comminuted Fractures with Femoral Defects

Aim

Distal femoral fractures account for 3–6% of all femoral fractures. Current management of distal femoral fractures involve reducing bone fragments and placing a locking plate against it. In this study, the surgeon used a ‘selective approach’, whereby only key bone fragments in the comminuted fracture were reduced and fixed whilst the rest were either removed or left unreduced/unfixed.

Method

All patients underwent AxSOS plate/less invasive stabilisation system (LISS) surgery for their comminuted femoral fracture after adopting the “selective approach” during pre-surgical planning. A significant proportion of patients had a degree of bone defect, and most had open fractures. Primary outcomes included post-operative functional ability, quality of life assessed using EQ-5D-5L, Oxford Hip Score (OHS), Oxford Knee Score (OKS), range of movement.

Results

Average OKS and OHS for our cohort (n=10) is 23 and 35, respectively, with a mean knee-flexion of 86° (45°-120°). Average EQ-5D- 5L index value is 0.551; the most common response for mobility, self-care, usual activities, pain/discomfort, and anxiety/depression was moderate. 20% developed pin site infections, 40% reported significant knee stiffness.

Conclusions

Despite a complex cohort whereby many patients had bone defects, and 80% had open fractures, the “selective approach” adopted in the present study achieved comparable outcomes to other studies with less-severe fracture characteristics, with similar operation times and range of knee-flexion. These results suggest that this alternative should be considered as a treatment option, although more studies on a similar cohort of patient to ours is needed to allow better comparison of the surgical approaches.

WE7.7 Bone transport using the Monorail External Fixator over an Intramedullary Nail for Post-Traumatic Femoral Defects

Aim

The management of limb-length discrepancy secondary to traumatic bone loss poses an unique challenge for surgeons. The Ilizarov technique is popular, but is associated with long external fixator time and many complications. This retrospective study assessed outcomes of post-traumatic femoral defects managed by monorail external fixation over an intramedullary nail.

Method

Eight patients were included from over a four-year period with post-traumatic femoral defects, that underwent treatment with monorail fixator-assisted intramedullary nailing. Mean follow-up time was 232.83 weeks. Five were open fractures (Gustilo-Anderson type 3A:n=4, 3B:n=1), one had closed fracture. Average bone defect size was 8cm. Primary outcomes were lengthening index, consolidation time and index, external fixator index. Secondary outcomes were time to full weight bearing (FWB), time to union, complications. Patient reported outcome measures including EQ-5D-5L, SF-36, Oxford knee scores (OKS), Oxford hip scores (OHS) were recorded after recovery.

Results

Average consolidation time and index were 11.35months and 1.24months/cm, respectively. Mean lengthening and external fixator index were 20.2days/cm and 23.88days/cm, respectively. On average, patients achieved FWB and bone union 56.25 weeks and 68.83 weeks after bone transport initiation, respectively. Two patients had docking site non-union, treated by reamed intramedullary exchange nailing. Two patients had osteomyelitis. EQ-5D-5L and EQ-VAS scores were compared to UK population norms (p=0.104, p=0.238, respectively). Average OKS was 32.17 and OHS was 34.00.

Conclusions

Monorail external fixation over an intramedullary nail is an effective option for post-traumatic femoral defects, reducing external fixator time, lowering complication rate, returning patients’ quality of life to a level comparable with the normal population.

EP-490 Management of femoral non-union with post-traumatic bone defect using second-generation PRECICE® nail - A Case Report

Introduction

The management of post-traumatic bone defects with non-union remains a surgical challenge. Common limb length discrepancy (LLD) procedures involve Masquelet technique, vascularised bone grafts, distraction osteogenesis using external fixators, yet they pose a functional and economical challenge for patients, given high complication rates and need for revision surgery. Magnetically-driven PRECICE nails are self-lengthening internal devices activated via an external controller. We present one patient with post-traumatic femoral non-union with concomitant bone defect, using second-generation PRECICE nail.

Case

One 57 year-old gentlemen suffered open femoral fracture after a motorcycle accident. Having previously undergone open reduction internal fixation, he presented to us with atrophic non-union and bone defect, which were simultaneously treated with a second-generation PRECICE nail. Our treatment protocol was based on the strain theory, and involved initial distraction by ∼5mm at non-union site, at a rate of 1mm per day, to decrease strain on bone graft cells and promote callus formation. One week later, the non-union site was compressed to close the gap completely. After another four weeks, distraction using the PRECICE nail started, in increments of 0.25mm, four times a day, until the desired length was achieved. The patient achieved union and the initially planned limb lengthening regime was achieved with minimal complications.

Conclusions

By initially distracting the bone defect by ∼5mm, then compressing the gap, before distraction started, strain on bone graft cells was minimised, allowing robust callus and regenerate growth. Self-lengthening, magnetically-driven PRECICE nails can successfully restore union and manage limb length discrepancies with reasonable patient satisfaction and minimal complications.

SP5.1.5 Risk factors for Septic Arthritis and need for Arthroscopic Washout: Minimum two year follow-up at a major trauma centre

Introduction

A hot swollen joint is commonly encountered in orthopaedics and rheumatology. With a broad range of differentials, septic arthritis (SA) is perhaps the most concerning, with delayed treatment leading to osteonecrosis, loss-of-joint-function, and mortality. To facilitate clinical decision making, we aimed to determine the risk factors for development of SA.

Methods

All patients presenting to the emergency department, orthopaedic and rheumatology clinics at our major trauma centre between January 2020 and January 2021 with a hot, swollen joint were retrospectively evaluated.

The frequency of variables of interest in the three-month period preceding the diagnosis of SA were compared between SA and non-SA patients using univariate analysis. A multiple logistic regression model was formed for covariates that were significantly associated with SA (p&lt;0.05), which underwent a backwards elimination process to identify a predictive model for SA. Multi-collinearity was assessed between covariates and variables with significant intercorrelation were removed. Statistical significance was set at p&lt;0.05.

Results

221 patients were included (SA: 28; periprosthetic joint infection: 24; pseudogout: 32; gout:26; other conditions: 111). Multivariate analysis showed that RA, skin infection, and liver disease were risk factors for SA, with odds ratios of 2.656 (95%CI:1.090–6.475;p=0.032), 3.162 (95:CI:1.269–7.883;p=0.013), 4.993 (95%CI:1.156–21.559;p=0.031), respectively.

Conclusion

With a high mortality and morbidity rate, early diagnosis of septic arthritis is crucial. This requires understanding what the risk factors are, namely RA, skin infection, and liver disease. We believe that the models in this study are of prognostic value to clinicians who are presented with the common presenting compliant of a hot swollen joint.

SP5.1.4 Prevention, Diagnosis, and Management of Fracture Related Infections in accordance with the BOA FRI Guidelines

Aim

Fracture related infections (FRI) are common and serious complications of musculoskeletal trauma. With average hospital health care costs for infected patients being 6.5 times higher than uninfected patients, FRI poses a significant social-economic burden to the patient and healthcare system.

We aim to audit current practice in preventing and diagnosing FRIs, and improve management of infections in patients with fractures. The guidelines covered are the British Orthopaedic Association (BOA) FRI guidelines.

Method

Our sample included patients who suffered an infection as a direct consequence of fracture and/or subsequent surgical management procedures over a seven-year period. Surgical procedures were performed for fractures in 8826 patients. In total, 102 patients with a FRI were reviewed. Audit results and recommendations have been presented at a clinical governance meeting.

Results

Seven out of sixteen items had poor compliance (&lt;80% compliance). Ultrasound-guided aspiration was done in 21.6% (22/102), even if debridement surgery is delayed. 1.96% (2/102) received adequate advice about responding to a suspected FRI. 56.9% had recommended 2-week antibiotic-free duration before sampling. Our recommendations include pre-written template in discharge documentation providing guidance on responding to a suspected FRI, better communication between microbiology, surgical team, and GPs regarding antibiotic prescription timing, including weekly bone and joint infection MDT review for FRI patients.

Conclusions

Lowering FRI-related burden requires a three-pronged approach: uniform set of standards for infection prevention in trauma and orthopaedic surgery, robust diagnostic workup for suspected FRI cases, effective management scheme for confirmed FRI cases. These systems should be a key element of orthopaedic trauma service.

SP5.2.1 Intra-muscular interposition of nerve endings to minimise neuropathic and residual pain in lower limb amputations

Introduction

A major cause of morbidity in lower limb amputees is phantom limb pain (PLP) and residual limb pain (RLP). This study aimed to determine if surgical interposition of nerve endings into adjacent muscle bellies at the time of major lower limb amputation can decrease the incidence and severity of PLP and RLP.

Methods

Data was retrospectively collected from January 2015 to January 2021, including eight patients that underwent nerve interposition (NI) and 36 that received standard treatment. Primary outcomes included the 11-point Numerical Rating Scale (NRS) for pain severity, and Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, behaviour, and interference. Secondary outcome included Neuro-QoL Lower Extremity Function assessing mobility. Cumulative scores were transformed to standardised t scores.

Results

Across all primary and secondary outcomes, NI patients had lower PLP and RLP. Mean ‘worst pain’ was 2 out of 10 for RLP in the NI group, compared to 3.58 in the control group (p=0.045). Mean PROMIS t scores were lower for NI cohort for both RLP (pain intensity [41.2 vs 48.1;p=0.035]; pain interference [44.9 vs 46.3;p=0.260]; pain behaviour [44.4 vs 50.8;p=0.039], and PLP (pain intensity [50.8 vs 58.5;p=0.029]; pain interference [49.1 vs 54.0;p=0.009]; pain behaviour [53.4 vs 55.6;p=0.061]). Mean Neuro-QoL t score was lower in NI cohort (45.4 vs 41.9;p=0.03).

Conclusion

Surgical interposition of nerve endings during lower limb amputation is a simple yet effective way of minimising PLP and RLP, improving patients’ subsequent quality of life. Additional comparisons with targeted muscle reinnervation should be performed to determine the optimal treatment option.

EP-494 Ankle Fusion with Tibiotalocalcaneal Retrograde Nail for Fragility Ankle Fractures: Outcomes at a Major Trauma Centre

Aim

Fragility ankles fractures in the geriatric population are challenging to manage, due to fracture instability, soft tissue compromise, and patient co-morbidities. Traditional management options include open reduction internal fixation, or conservative treatment, both of which are fraught with high complication rates. We aimed to present functional outcomes of elderly patients with fragility ankle fractures treated with retrograde ankle fusion nails.

Method

171 patients received a tibiotalocalcaneal nail over a six-year period, but only twenty met the inclusion criteria of being over sixty and having poor bone stock. Primary outcome was mortality risk from co-morbidities according to Charlson co-morbidity index (CCI), and patients’ post-operative mobility status compared to pre-operative mobility. Secondary outcomes include intra-operative and post-operative complications, six-month mortality rate, time to mobilisation and union.

Results

Mean age was 77.82 years old. The average CCI was 5.05. Thirteen patients returned to their pre-operative mobility state. Patients with low CCI are more likely to return to pre-operative mobility status (p=0.16;OR=4.00).

Average time to bone union and mobilisation were 92.5 days and 7.63 days, respectively. Mean post-operative AOFAS ankle-hindfoot and Olerud-Molander scores were 53.0 and 50.9, respectively. There were four cases of superficial infection. Patients with high CCI were more likely to acquire superficial infections (p=0.264,OR=3.857). There were no deep infections, periprosthetic fractures, nail breakages, non-unions. Average follow-up time was 499.3 days.

Conclusions

Tibiotalocalcaneal nailing is an effective and safe option for managing fragility ankle fractures in the elderly. This technique leads to lower complication rates and earlier mobilisation than traditional fixation methods.

Open versus closed pilon fractures: Comparison of management, outcomes, and complications

BACKGROUND

Despite the low incidence of pilon fractures amongst lower limb injuries, their high impact nature presents difficulties in surgical management and recovery. The high complication rate and long recovery times presents a challenge for surgeons and patients. Current literature is varied, with no universal treatment algorithm. We aim to highlight differences in outcomes and complications between open and closed pilon fractures, and between patients treated by open reduction internal fixation (ORIF) or fine wire fixator (FWF) for open and closed fracture subgroups.

METHODS

This retrospective study was conducted at a major trauma centre including 135 patients over a 6-year period. Primary outcome was AOFAS score at 3, 6, and 12-months post-injury. Secondary outcomes included time to partial weight-bear (PWB) and full weight-bear (FWB), bone union time, and complications during the follow-up time. AO/OTA classification was used (43A: n = 23, 43B: n = 30, 43C: n = 82). Interobserver agreement was high for bone union time (kappa=0.882) and AO/OTA class (kappa=0.807).

RESULTS

Higher AOFAS scores were seen in ORIF groups of both open and closed fractures, compared to FWF groups. The difference was not statistically significant apart from 12-month AOFAS score of 43C open fractures (p = 0.003) and in 43B closed fractures 3 and 6 months post-injury (p<0.001 and p<0.001, respectively). The majority of ORIF subgroups, open and closed fractures, also had shorter time to PWB, FWB, time to union, and follow-up. Statistically significant differences were seen in the following cases: ORIF-treated 43B closed fracture subgroup had shorter time to PWB and FWB (p<0.001 and p = 0.017, respectively), ORIF-treated 43C closed fractures had shorter time to union (p = 0.005). Common complications for open fractures were non-union (24%), post-traumatic arthritis (16%); for closed fractures they were post-traumatic arthritis (24%), superficial infection (21%). All occurred more frequently in FWF-treated patients.

CONCLUSION

Most ORIF-treated subgroups in either open or closed pilon fractures showed better primary and secondary outcomes than FWF-treated subgroups, yet few were statistically significant. Overall, our use of a two-staged approach involving temporary external fixation, followed with ORIF or FWF achieved low complication rates and good functional recovery.

Fracture Related Infections and Their Risk Factors for Treatment Failure—A Major Trauma Centre Perspective

Fracture related infections (FRI) are debilitating and costly complications of musculoskeletal trauma surgery that can result in permanent functional loss or amputation. Surgical treatment can be unsuccessful, and it is necessary to determine the predictive variables associated with FRI treatment failure, allowing one to optimise them prior to treatment and identify patients at higher risk. The clinical database at a major trauma centre was retrospectively reviewed between January 2015 and January 2021. FRI treatment failure was defined by infection recurrence or amputation. A univariable logistic regression analysis was performed, followed by a multivariable regression analysis for significant outcomes between groups on univariable analysis, to determine risk factors for treatment failure. In total, 102 patients were identified with a FRI (35 open, 67 closed fractures). FRI treatment failure occurred in 24 patients (23.5%). Risk factors determined by our multivariate logistic regression model were obesity (OR 2.522; 95% CI, 0.259–4.816; p = 0.006), Gustilo Anderson type 3c (OR 4.683; 95% CI, 2.037–9.784; p = 0.004), and implant retention (OR 2.818; 95% CI, 1.588–7.928; p = 0.041). Given that FRI treatment in 24 patients (23.5%) ended up in failure, future management need to take into account the predictive variables analysed in this study, redirect efforts to improve management and incorporate adjuvant technologies for patients at higher risk of failure, and implement a multidisciplinary team approach to optimise risk factors such as diabetes and obesity.

The Use of Autologous Chondrocyte and Mesenchymal Stem Cell Implants for the Treatment of Focal Chondral Defects in Human Knee Joints-A Systematic Review and Meta-Analysis

Focal chondral defects of the knee occur commonly in the young, active population due to trauma. Damage can insidiously spread and lead to osteoarthritis with significant functional and socioeconomic consequences. Implants consisting of autologous chondrocytes or mesenchymal stem cells (MSC) seeded onto scaffolds have been suggested as promising therapies to restore these defects. However, the degree of integration between the implant and native cartilage still requires optimization. A PRISMA systematic review and meta-analysis was conducted using five databases (PubMed, MEDLINE, EMBASE, Web of Science, CINAHL) to identify studies that used autologous chondrocyte implants (ACI) or MSC implant therapies to repair chondral defects of the tibiofemoral joint. Data on the integration of the implant-cartilage interface, as well as outcomes of clinical scoring systems, were extracted. Most eligible studies investigated the use of ACI only. Our meta-analysis showed that, across a total of 200 patients, 64% (95% CI (51%, 75%)) achieved complete integration with native cartilage. In addition, a pooled improvement in the mean MOCART integration score was observed during post-operative follow-up (standardized mean difference: 1.16; 95% CI (0.07, 2.24), p = 0.04). All studies showed an improvement in the clinical scores. The use of a collagen-based scaffold was associated with better integration and clinical outcomes. This review demonstrated that cell-seeded scaffolds can achieve good quality integration in most patients, which improves over time and is associated with clinical improvements. A greater number of studies comparing these techniques to traditional cartilage repair methods, with more inclusion of MSC-seeded scaffolds, should allow for a standardized approach to cartilage regeneration to develop.

Risk factors for septic arthritis and multiple arthroscopic washouts: minimum 2-year follow-up at a major trauma centre

Background

Septic arthritis (SA) is a dangerous condition that requires emergency treatment. Managed by culture-specific antibiotics, irrigation, and debridement (I&D), some patients require repeat surgical treatment. The objectives were to determine the risk factors for SA and risk factors for repeat arthroscopic I&D in SA patients. We hypothesized that variables which directly or indirectly contributed to a larger infection burden would be associated with the development of SA and the need for repeat arthroscopic I&D.

Methods

All patients ≥ 18 years old presenting to the emergency department, orthopaedic and rheumatology clinics at our major trauma centre between January 2018 and January 2020 with a hot, swollen joint were retrospectively evaluated. Patients with previous trauma and metalwork in the affected joint, periprosthetic joint infection, previous joint arthroplasty surgery, soft tissue infection, missing data, transferred to another centre, diagnosis not concerning the joint, and < 24-month follow-up were excluded. Two hundred eleven patients were included (SA: 28; pseudogout: 32; gout: 50; others: 101). Variables of interest in the 3-month period preceding the diagnosis of SA were compared between SA and non-SA patients using univariable analysis. A multivariable logistic regression model was formed using covariates with corresponding univariable tests of p < 0.200. Similar analyses were performed to compare SA patients with multiple washouts/procedures with those with one washout/procedure.

Results

Multivariable analysis showed multiple risk factors for SA, namely rheumatoid arthritis (RA) (OR: 3.4; 95% CI: 1.2–10.0; p = 0.023); skin infection (OR: 3.3; 95% CI: 1.2–9.0; p = 0.017), liver disease (OR: 9.9; 95% CI: 2.2–43.9; p = 0.003), knee joint involvement (OR: 3.5; 95% CI: 1.3–9.4; p = 0.014), and use of immunosuppressive medication (OR: 3.5; 95% CI: 1.2–10.6; p = 0.027). Risk factors for multiple washouts included synovial WBC levels > 10.5 × 10⁹ cells/L (OR: 3.0; 95% CI: 2.3–38.8; p = 0.009) and RA (OR: 3.5; 95% CI: 1.9–66.3; p = 0.017).

Conclusions

These findings suggest that prophylactic actions against septic arthritis should be targeted at patients with liver disease, RA, or skin infection. Repeat arthroscopic I&D of septic joints may be needed, especially in patients with synovial WBC levels > 10.5 × 10⁹ cells/L and RA.

Key Points • The risk factors for septic arthritis determined in this study are rheumatoid arthritis, skin infection, liver disease, knee joint involvement, and immunosuppressant usage. • Some septic arthritis patients need multiple rounds of arthroscopic irrigation and debridement. The risk factors for this are a synovial WBC count > 10.5 × 109 cells/L and rheumatoid arthritis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10067-022-06151-w.

Systematic Review of Epigenetic Therapies for Treatment of IDH-mutant Glioma

BACKGROUND

Isocitrate dehydrogenase (IDH) mutations are present in 70% of World Health Organization grade II and III gliomas. IDH mutation induces accumulation of the oncometabolite 2-hydroxyglutarate. Therefore, therapies targeting reversal of epigenetic dysregulation in gliomas have been suggested. However, the utility of epigenetic treatments in gliomas remains unclear. Here, we present the first clinical systematic review of epigenetic therapies in treatment of IDH-mutant gliomas and highlight their safety and efficacy.

METHODS

We conducted a systematic search of electronic databases from 2000 to January 2021 following PRISMA guidelines. Articles were screened to include clinical usage of epigenetic therapies in case reports, prospective case series, or clinical trials. Primary and secondary outcomes included safety/tolerability of epigenetic therapies and progression-free survival/overall survival, respectively.

RESULTS

A total of 133 patients across 8 clinical studies were included in our analysis. IDH inhibitors appear to have the best safety profile, with an overall grade 3/grade 4 adverse event rate of 9%. Response rates to IDH-mutant inhibitors were highest in nonenhancing gliomas (stable disease achieved in 55% of patients). In contrast, histone deacetylase inhibitors demonstrate a lower safety profile with single-study adverse events as high as 28%.

CONCLUSION

IDH inhibitors appear promising given their benign toxicity profile and ease of monitoring. Histone deacetylase inhibitors appear to have a narrow therapeutic index, as lower concentrations do not appear effective, while increased doses can produce severe immunosuppressive effects. Preliminary data suggest that epigenetic therapies are generally well tolerated and may control disease in certain patient groups, such as those with nonenhancing lesions.

Management of femoral non-union with post-traumatic bone defect using second-generation PRECICE® nail - A case report

The management of post-traumatic bone defects with non-union remains a surgical challenge. Current techniques are often fraught with complications, posing a functional, economical, and psychological challenge for the patient. A 57 year-old gentlemen suffered an open femoral fracture after a motorcycle accident. Having previously undergone open reduction internal fixation, he presented to us with atrophic non-union and bone defects, which were simultaneously treated with a second-generation PRECICE nail. Our treatment protocol was based on the strain theory, and involved initial distraction by ~5 mm at the non-union site, compression of the non-union site, followed by distraction osteogenesis at the non-union site. The patient achieved union and the initially planned limb lengthening regime was achieved with minimal complications. Self-lengthening, magnetically-driven PRECICE nails can successfully restore union and manage limb length discrepancies with reasonable patient satisfaction and minimal complications.

SURG-04. THE CLINICAL COURSE AND ROLE OF SURGERY IN PEDIATRIC MALIGNANT PERIPHERAL NERVE SHEATH TUMORS: A DATABASE STUDY

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare tumors found throughout the body, with their clinical course in children still to be completely understood. Correspondingly, this study aimed to determine survival outcomes and specific clinical predictors of survival in this demographic from a large national database.

METHODS

All MPNST patients aged ≤18 year in the U.S. National Cancer Database (NCDB) between 2005-2016 were retrospectively reviewed. Data were summarized and overall survival (OS) was modeled using Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 251 pediatric MPNST cases were identified. Overall, mean age at diagnosis was 13.1 years (range, 1-18) with there being 132 (53%) females and 119 (47%) males. There were 84 (33%) MPNSTs located in extremities, 127 (51%) less than 1cm in size, and 22 (9%) have metastasis at diagnosis. In terms of treatment, surgery was pursued in 187 (74%) patients, chemotherapy in 116 (46%) patients, and radiation therapy in 129 (61%) patients. Five-year overall survival was estimated to be 52% (95% CI, 45-59%), and with median survival of 64 months (range, 36-136). Multivariate regression revealed older age (HR 1.10, P&lt; 0.01), with metastases at time of diagnosis (HR 2.14, P=0.01), and biopsy only (HR 2.98, P&lt; 0.01) all significantly and independently predicted shorter overall survival. Chemotherapy and radiation therapy were not statistically significant.

CONCLUSIONS

Pediatric MPNSTs are rare malignant entities, and only approximately half of patients will survive to five years. There remains a clear survival benefit in pursuing maximal safe resection in these patients. As such, judicious workup with meticulous surgical resection by an expert team should then be considered the standard of care for these tumors in children.

EPID-16. DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR IN PEDIATRIC PATIENTS: A QUANTITATIVE EXPLORATION

BACKGROUND

Diffuse leptomeningeal glioneuronal tumor (DLGNT), also known as oligodendrogliomatosis, is a rare neuro-oncologic condition along the neuraxis that remains poorly understood in children. We sought to describe our institutional experience and quantitively summarize the clinical survival and prognostic features of DLGNT in the pediatric population across the contemporary literature.

METHODS

We report four institutional cases of pediatric DLGNT diagnosed between 2000-2020 based on retrospective review of our records, and performed a comprehensive literature search for published cases from 2000 onwards to create an integrated cohort for analysis. Kaplan-Meier estimations, Fisher’s exact test, and logistic regression were utilized to interrogate the data.

RESULTS

Our overall integrated cohort consisted of 54 pediatric DLGNT patients, with 19 (35%) female and 35 (65%) male patients diagnosed at an average age of 6.4 years (range, 1.3-17 years) by means of surgical biopsy. Chemotherapy was used in 45 cases (83%), and mean follow-up time of 54 months (range, 3-204). Across the entire cohort, overall survival 1 month after diagnosis was 96% (95% CI 86-99%), and by 10 years was 69% (95% CI 49-82%). On multivariate analysis of complete data, chemotherapy treatment (HR=0.23, P=0.04) was statistically predictive of longer overall survival. When including limited data, longer duration of symptoms by presentation (HR=1.03, P=0.03) was statistically predictive of shorter overall survival.

CONCLUSIONS

This is the first quantitative study of pediatric DLGNT clinical course. More than 2-out-of-3 pediatric DLGNT patients survive beyond one decade. Chemotherapy is statistically associated with longer survival in DLGNT pediatric patients and should form the core of any treatment regimen in this setting. Early detection by means of judicious imaging and surgical biopsy for tissue diagnosis can lead to earlier treatment and likely superior outcomes.

CNTM-01. Evaluating Traditional and Non-Traditional Eloquent Areas in Patients with Brain Tumors: Large-scale Network Analysis Using a Machine Learning-Based Platform

BACKGROUND

Developing mapping tools that allow identification of traditional or non-traditional eloquent areas is necessary to minimize the risk of postoperative neurologic deficits. The objective of our study is to evaluate the use of a novel cloud-based platform that uses machine learning to identify cerebral networks in patients with brain tumors.

METHODS

We retrospectively included all adult patients who underwent surgery for brain tumor resection or thermal ablation at our Institution between the 16th of February and the 15th of May of 2021. Pre and postoperative contrast-enhanced MRI with T1-weighted and high-resolution Diffusion Tensor Imaging (DTI) sequences were uploaded into the Quicktome platform. After processing the data, we categorized the integrity of seven large-scale brain networks: sensorimotor, visual, ventral attention, central executive, default mode, dorsal attention and limbic. Affected networks were correlated with pre and postoperative clinical data, including neurologic deficits.

RESULTS

Thirty-five (35) patients were included in the study. The average age of the sample was 63.2 years, and 51.4% (n=18) were females. The most affected network was the central executive network (40%), followed by the dorsal attention and default mode networks (31.4%), while the least affected were the visual (11%) and ventral attention networks (17%). Patients with preoperative deficits showed a significantly higher number of altered networks before the surgery (p=0.021), compared to patients without deficits. In addition, we found that patients without neurologic deficits had an average of 2.06 large-scale networks affected, with 75% of them not being related to traditional eloquent areas as the sensorimotor, language or visual circuits.

CONCLUSIONS

The Quicktome platform is a practical tool that allows automatic visualization of large-scale brain networks in patients with brain tumors. Although further studies are needed, it may assist in the surgical management of traditional and non-traditional eloquent areas.

537 Open vs Closed Pilon Fractures: Comparison of Management, Outcomes, and Complications

Aim

Despite the low incidence of pilon fractures, their high impact nature presents difficulties in surgical management/recovery. Current literature is varied, with no universal treatment algorithm. We aim to highlight differences in treatment, outcomes, complications between open and closed pilon fractures.

Method

This retrospective study was conducted at a major trauma centre, including patients over 5-year period. 135 patients were included (open:48, closed:87). Primary outcome was AOFAS score at 3-, 6- and 12-months post-injury. Secondary outcomes include time to partial weight-bear (PWB) and full weight-bear (FWB), bone union time, follow-up time. Post-operative complications were collected.

Results

Open fractures had lower AOFAS score 3 months post-injury, longer bone union time, and time to FWB. For both open and closed fractures, compared to ORIF patients, those treated with fine wire fixator (FWF) had lower AOFAS scores 3- and 6-months post-injury. Closed fracture patients treated with ORIF had shorter bone union time, time to PWB and FWB. Patients with AO/OTA 43A fractures needed shorter time to PWB and FWB than those with 43C fractures. Common complications (closed:open) were superficial infection (22%:54%), post-traumatic arthritis (25%:16%), non-union (11%:24%).

Conclusions

Open fractures, with more extensive soft tissue damage, were likely more suited for FWF, rather than ORIF (18% of open vs 72% of closed were treated with ORIF). Due to greater associated trauma, more frequent complications, and delayed definitive fixation, open fractures had lower AOFAS scores. Nevertheless, use of staged approach involving temporary external fixation, followed with ORIF or FWF achieved low complication rates and good functional recovery.

Mesenchymal Stem Cell-Derived Extracellular Vesicles in Tendon and Ligament Repair-A Systematic Review of In Vivo Studies

Tendon and ligament injury poses an increasingly large burden to society. This systematic review explores whether mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) can facilitate tendon/ligament repair in vivo. On 26 May 2021, a systematic search was performed on PubMed, Web of Science, Cochrane Library, Embase, to identify all studies that utilised MSC-EVs for tendon/ligament healing. Studies administering EVs isolated from human or animal-derived MSCs into in vivo models of tendon/ligament injury were included. In vitro, ex vivo, and in silico studies were excluded, and studies without a control group were excluded. Out of 383 studies identified, 11 met the inclusion criteria. Data on isolation, the characterisation of MSCs and EVs, and the in vivo findings in in vivo models were extracted. All included studies reported better tendon/ligament repair following MSC-EV treatment, but not all found improvements in every parameter measured. Biomechanics, an important index for tendon/ligament repair, was reported by only eight studies, from which evidence linking biomechanical alterations to functional improvement was weak. Nevertheless, the studies in this review showcased the safety and efficacy of MSC-EV therapy for tendon/ligament healing, by attenuating the initial inflammatory response and accelerating tendon matrix regeneration, providing a basis for potential clinical use in tendon/ligament repair.

Abstract LB145: CoupledCARTMtechnology for treating thyroid cancer

Chimeric antigen receptor modified T cells (CAR T) have demonstrated remarkable clinical efficacy in the treatment of B cell malignancies and multiple myeloma. Significant challenges restrict their application across solid tumors due to multiple obstacles, including the lack of robust in vivo CAR-T cell expansion and persistence, the immunosuppressive tumor microenvironment.To address these difficulties, we generated CAR T cells using a novel CoupledCAR® technology. Specifically, we engineered CoupledCAR T cells with lentiviral vectors encoding an anti-thyroid stimulating hormone receptor (TSHR) CAR molecule. Immunohistochemistry (IHC) results showed that TSHR was highly expressed in thyroid cancer cells making it an ideal tumor-specific target antigen. In vitro co-culture experiments showed that TSHR CAR T cells specifically recognized and subsequently killed TSHR-positive tumor cells. Animal model experiments showed that TSHR CAR T cells inhibited the proliferation of TSHR-positive tumor cells.To evaluate the clinical safety and efficacy of anti-TSHR CoupledCAR T cells on refractory or relapsed thyroid cancer, we treated refractory/relapsed post-thyroidectomy thyroid cancer patients according to an IRB approved protocol. We treated two patients using anti-TSHR CoupledCAR T cells and observed the rapid expansion of CAR T cells and enhanced the killing of tumor cells. One patient's best response was complete remission, and the other was near complete remission.Patient 1 Male, 64Y, Papillary Thyroid Carcinoma. In May 2017, Thyroid cancer was diagnosed, bilateral total thyroidectomy, and right cervical lymph node functional dissection were performed in Jun 2018, followed by iodine 131 isotope therapy. In December 2018, bilateral multiple cervical lymph nodes were enlarged, especially on the right side. In February 2019, right neck lymphadenectomy was performed.Patient 2 Female, 60Y, Thyroid Carcinoma. In Aug 2013, a "double lobectomy of the thyroid gland” was performed. From Oct 2013 to Jan 2014, she received iodine 131 isotope therapy. In Sep 2014, she was diagnosed with iodine - resistant thyroid cancer. From Sep to Jan 2016, 5 cycles of chemotherapy were performed. In Jun 2016, she enrolled in the Anlotinib experimental group. In Mar 2019, multiple metastases in both lungs and multiple enlarged lymph nodes in the mediastinum were observed.Patient 1: One month after infusion (M1), the patient was evaluated as PR. Three months after infusion (M3), the patient was evaluated as CR, and the patient's CR lasted from M3 to M12 after infused anti-TSHR CoupledCAR T cells , and we are still following up.Patient 2: M1, the patient was evaluated as PR (Partial Response): the tumor volume in the right lower lobe of the lung was reduced by approximately 67.51% (decreased from 65*55mm to 42*39mm). Three months after infusion (M3), compared with that before, the tumor volume was reduced by approximately 73.54% and SUV max value decreased from 14.9 to 2.8, therefore, the patient was evaluated as nCR (near complete remission).We show that TSHR is a good target for treating thyroid cancer, and our anti-TSHR CoupledCAR T cells are safe and effective for treating thyroid cancer. Recruitment is ongoing to evaluate the safety and efficacy of our CoupledCAR T cells. Further, since our CoupledCAR® technology is a platform technology, we are developing it to treat other solid tumors using different target tumor markers.

Citation Format: Lei Xiao, Xingchen Liu, Keshu Zhou, Yu Liu, Yong Huang, Chengfei Pu, Zhiyuan Cao, Ruihong Zhu, Haiyang Tang, Zhipeng Huang, Hang Yang, Xi Huang, Yongping Song, Renbin Liu, Zhao Wu, Victor Lu. CoupledCARTMtechnology for treating thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB145.

Abstract LB146: Novel coupledCARTMtechnology for treating colorectal cancer

Chimeric antigen receptor (CAR) T cell therapy has made significant progress in the treatment of blood cancers such as leukemia, lymphoma, and myeloma. However, the therapy faces many challenges in treating solid tumors. These challenges include physical barriers, tumor microenvironment immunosuppression, tumor heterogeneity, target specificity, and limited reactive cell expansion in vivo.Conventional CAR T cell therapy has thus far shown weak cell expansion in solid tumor patients and achieved little or no therapeutic responses. Here, we developed CAR T cells based on a novel CoupledCAR® technology to treat solid tumors. In contrast to conventional CAR T cells, CoupledCAR T cells significantly improved the expansion of the CAR T cells in vivo and enhanced the CAR T cells' migration ability and resistance to immunosuppression by the tumor microenvironment. The enhanced migration ability and resistance allow the CAR T cells to infiltrate to tumor tissue sites and increase anti-tumor activities.Specifically, we engineered CoupledCAR T cells with lentiviral vectors encoding an anti-GCC (guanylate cyclase 2C) CAR molecule. Furthermore, anti-GCC CAR T cells showed anti-tumor activities in vitro and in vivo experiments.To verify the safety and efficacy of CoupledCAR T cells for treating solid tumors, we conducted several clinical trials for different solid tumors, including seven patients with colorectal cancer. These seven patients failed multiple rounds of chemotherapy and radiotherapy. In the clinical trial, the patients were infused with autologous anti-GCC CoupledCAR T cells range from 4.9×10^5/kg to 2.9×10^6/kg. All patients using anti-GCC CoupledCAR T cells showed rapid expansion of CoupledCAR T cells and killing of tumor cells. Specifically, we observed that CoupledCAR T cells expanded significantly in the patients and infiltrated tumor tissue sites, demonstrating enhanced anti-tumor activities. PET/CT showed significant tumor shrinkage and SUV max declined, and the ongoing responses were monitored. Patient 3 achieved complete response and the best overall response rate (ORR, include complete remission, complete metabolic response, partial response, and partial metabolic response.) was 57.1% (4/7), complete remission (CR) rate was 14.3% (1/7).The clinical data demonstrated that CoupledCAR T cells effectively expanded, infiltrated tumor tissue sites, and kill tumor cells in patients with colorectal cancer. We used immunotherapy to achieve complete remission in patients with advanced colorectal cancer for the first time. We are recruiting more colorectal cancer patients to further test the safety and efficacy of anti-GCC CoupledCAR T cells. Since our CoupledCAR® technology is a platform technology, we are expanding it to treat other solid tumors using different target tumor markers.

Citation Format: Lei Xiao, Song Li, Chengfei Pu, Zhiyuan Cao, Xinyi Yang, Ning Li, Youli Luo, Haiyan Zhao, Hang Yang, Xi Huang, Xiaogang Shen, Xiuwen Wang, Yongping Song, Junjie Mao, Pengfei Pang, Qun Hu, Zhao Wu, Victor Lu. Novel coupledCARTMtechnology for treating colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB146.