Instruments based on shape-memory alloy properties for minimal access surgery, interventional radiology and flexible endoscopy

Nickel-related hypersensitivity reactions following endovascular interventions: A review of current evidence

INTRODUCTION

Nickel is a principal alloying agent in the production of vascular endoprostheses, despite persisting as the most habitually identified allergen. Variable nickel-related hypersensitivity manifestations following endovascular intervention were reported, challenging established paradigms in treatment and accuracy of prognostic assessments. The objective of this review is to critically evaluate current metrics to maximise patient-related outcomes.

METHODS

A literature review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 statement. Patients indicative of nickel hypersensitivity reaction following endovascular intervention were discerned. A positive reaction was defined by patch testing, histological analysis, or anamnesis indicative of nickel hypersensitivity. Morphology of implicating prostheses, adverse events and postoperative complications, clinical course, diagnostic and therapeutic strategies alongside patient prognosis were recorded.

RESULTS

Nickel-related hypersensitivity reactions following endovascular repair were identified in 36 patients with a median age of 44.5 years. 20 patients received nitinol-containing intervention. 28 (77.8%) patients are female. Multi-organ adverse reactions occurred in 21 (58.3%) patients with variable latency. 14 (38.9%) patients were presented with neurological adverse reactions manifesting mainly as unilateral hemiparesis. Dermatological reactions implicated 16 (44.4%) patients. Miscellaneous manifestations include suicidal ideation. 13 (36.1%) patients displayed previous metal intolerance and 32 (88.9%) patients had positive patch testing for nickel. Histological analysis of lesions and prostheses indicated lymphocytic infiltration. 5 (13.9%) patients experienced device-specific reactions as in-stent restenosis or auxiliary distal vessel stenosis. 11 (30.1%) patients received solely medical therapy and 5 (13.9%) patients received solely surgical therapy. 19 (52.7%) patients underwent both medical (oral corticosteroid) and surgical therapy (device retrieval). 26 (77.1%) patients achieved symptomatic cessation, 6 (16.7%) patients exhibited symptomatic persistence and 0 patients died.

CONCLUSION

Prophylactic pre-assessment for a history of metal allergy and consideration of prostheses alternatives is recommended to minimise reaction risk and severity. Despite nickel's predominant usage, information paucity urges additional studies to emphasise its implications and maximise patient outcomes.

Current and future practices in surgical retraction

Retraction of tissues and anatomical structures is an essential component of all forms of surgery. The means by which operative access is gained through retraction are many and diverse. In this article, the various forms of retraction methods currently available are reviewed, with special reference to hand held, self-retaining and compliant techniques. The special challenges posed by laparoscopic surgery are considered and future developments in new retraction techniques are anticipated.

A guide to shape memory and superelasticity in Nitinol medical devices

Shape memory and superelasticity properties of Nitinol have allowed the development of many novel medical devices. The intent of this paper is to approach the shape memory effect from the perspective of the attributes of a simple, yet elegant Nitinol device, the Homer Mammaloktrade mark needle localizer. Manufacturing methods, deformation behavior and temperature dependence of the device will be briefly reviewed.

Skin wound closure with a novel shape-memory alloy fixator

BACKGROUND

Previously, we have described novel, thermally deployable tissue fixators based on the shape-memory properties of nickel titanium. The present study reports on the in vivo wound closure with these fixators as a preliminary to evaluating their use for bowel anastomoses.

METHODS

Twenty adult Sprague-Dawley rats had 2.0-cm dorsal skin incisions approximated either with shape-memory alloy (SMA) fixators or conventional skin staples on a random basis. Electrical resistance heating was used to transform and deploy the SMA fixators into the wound. The rats were killed on day 14 or day 28 and wound specimens were harvested for force distraction studies and histologic examination.

RESULTS

There was no incidence of wound dehiscence. 14- and 28-day wounds from both groups showed no significant difference in breaking force or energy. Histology revealed appropriate stages of wound healing for both SMA-closed and control wounds.

CONCLUSIONS

The results confirm the efficacy and safety of tissue-edge approximation with SMA fixators.