Double fusion, a depth perception mechanism in Panum's limiting case

The origin of depth in Panum's limiting case is unclear at present, so we investigated the depth perception mechanism using a triangle type of Panum's stimulus with a slant effect and clear criterion. Experiment 1 explored whether participants can correctly perceive fixation and nonfixation features using the fixation point and quick representation of stimuli, then examined whether participants' depth judgments supported double fusion or single fusion. The results of Experiment 1 showed that participants could correctly perceive the depth of fixation and nonfixation features. That is, it supported double fusion. In Experiment 2, we examined whether the depth perceived by observers comes from depth contrast. The results of Experiment 2 showed that the depth of the two features perceived after binocular fusion did not originate from the depth contrast. The findings suggest that the depth perception mechanism of Panum's limiting case is more likely to be double fusion.

Surgical Construct Associated with Time to Fusion in Double and Isolated Talonavicular Arthrodeses

Category:

Hindfoot; Ankle Arthritis

Introduction/ Purpose:

Double arthrodesis of the subtalar (ST) and talonavicular (TN) joints, along with isolated TN arthrodesis, are commonly performed for hindfoot osteoarthritis and rigid hindfoot deformity. Few studies have examined the effects of the type of ST and TN fixation constructs on nonunion rate following double and isolated TN arthrodesis procedures. This study evaluates the effect of surgical construct on the union rate and time to fusion in patients undergoing double or isolated TN arthrodesis.

Methods:

Retrospective chart review identified 52 patients (52 feet) who underwent double or isolated TN arthrodesis between 2016 and 2021 by a fellowship-trained foot and ankle surgeon with at least six months of follow-up (mean=1.62 years, range=0.50- 4.39 years). Data collected included demographics, medical history, surgical indication, surgical constructs used, complications, reoperations, patient-reported outcome measures, and radiographic measures. ST constructs included one (n=4) or two (n=44; parallel=43, divergent=1) cannulated screws, while TN constructs included dorsal plate (n=2), dorsal plate and screw (n=10), isolated screws (n=3) screw and staple (n=29), or isolated staples (n=13). At the time of their surgery, the mean age was 60.39 (range, 17-80) years, mean body mass index (BMI) was 33.89 (range, 20.74-48.41) kg/m2, and most subjects were non-smokers (94.7%). Mean follow-up duration was 1.62 (range, 0.50-4.39) years.

Results:

Overall complication and reoperation rates were 26.3% and 12.3%, respectively. Among TN constructs, the time to ST (p=.026) and TN (p=.018) fusion was statistically significantly slower among patients receiving a plate and screw TN construct. Complication rate did not differ by construct, but reoperation rate was significantly higher for the plate and screw TN construct (p=.039). Postoperative Foot and Ankle Outcome Score (FAOS) Quality of Life (p=.028) and Total (p=.016) scores were significantly better among plate and screw TN constructs.

Conclusion:

The utilization of a screw and staple or isolated staple construct have a statistically significantly quicker time to fusion and lower reoperation rates than plate and screw constructs for the TN joint. These findings can be used to guide clinician decision-making while allowing physicians to take their personal construct preference into account, as well as serve as a useful starting point to other researchers interested in investigating the impact of surgical constructs on ST and TN fusions.

Case Report: A novel ELMOD3-ALK and EML4-ALK double-fusion responses to neoadjuvant alectinib in a lung adenocarcinoma patient

Background

Anaplastic lymphoma kinase (ALK) rearrangements account for approximately 3%-5% of non-small cell lung cancer (NSCLC), and the echinoderm microtubule-associated protein-like 4 gene (EML4) and ALK fusion (EML4-ALK) is the most common ALK rearrangement in NSCLC patients. However, double-ALK fusion is extremely rare in clinical practice. Herein, we first report a lung adenocarcinoma patient with the coexistence of a novel subfamily 3 of ELMOD (ELMOD3)-ALK, EML4-ALK double fusion that is sensitive to alectinib target therapy.

Materials and methods

Hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC), and next-generation sequencing (NGS) were performed on biopsy samples.

Results

The IHC analysis confirmed positive expression of ALK protein. NGS revealed a novel ELMOD3-ALK and EML4-ALK double fusion. The patient was sensitive to alectinib as neoadjuvant therapy and achieved a major pathological response (MPR), which was confirmed by the postoperative pathology diagnosis. To date, the patients' disease-free survival (DFS) has exceeded 4 years without any significant symptoms of toxicity.

Conclusion

This is the first report of one lung adenocarcinoma patient with a novel ELMOD3-ALK, EML4-ALK double-ALK fusion. This double-ALK fusion variant is sensitive to alectinib, suggesting patients with an ELMOD3-ALK, EML4-ALK double-ALK fusion could achieve clinical survival benefit from alectinib.

Surgical Construct Type Is Associated With Time to Fusion and Reoperation Rate in Double and Isolated Talonavicular Arthrodeses

BACKGROUND

This study evaluates the effect of surgical construct on postoperative outcomes in patients undergoing isolated talonavicular (TN) or double (TN and subtalar ST) arthrodesis. TN constructs included plate and screw, screw and staple, and isolated staple constructs. Subtalar constructs included 1- and 2-screw constructs.

METHODS

Retrospective chart review identified 52 patients who underwent double or isolated TN arthrodesis between 2016 and 2021 by a single fellowship-trained foot and ankle surgeon with minimum 6 months of follow-up (mean = 1.62 years, range = 0.50-4.39 years). Data collected included demographics, medical history, surgical indication, surgical constructs used, complications, reoperations, patient-reported outcome measures, and radiographic measures.

RESULTS

Overall complication and reoperation rates were 26.3% and 12.3%, respectively. Among TN constructs, time to ST (P = .026) and TN (P = .018) fusion was significantly slower among patients receiving a plate and screw construct. Complication rate did not differ, but reoperation rate was significantly higher for plate and screw TN constructs (P = .039). Postoperative Foot and Ankle Outcome Score (FAOS) Quality of Life (P = .028) and Total (P = .016) scores were significantly better among plate and screw TN constructs.

CONCLUSION

Utilization of screw and staple or isolated staple construct have significantly quicker time to fusion and lower reoperation rates than plate and screw constructs for the TN joint.

LEVEL OF EVIDENCE

Level III: Retrospective cohort study.