Failure of facet replacement system with metal-on-metal bearing surface and subsequent discovery of cobalt allergy: report of 2 cases

Advances in Implant Technologies for Spine Surgery

Spine implants are becoming increasingly diversified. Taking inspiration from other industries, three-dimensional modeling of the spinal column has helped meet the custom needs of individual patients as both en bloc replacements and pedicle screw designs. Intraoperative tailoring of devices, a common need in the operating room, has led to expandable versions of cages and interbody spacers.

Hypersensitivity reactions to metals in spine surgery

Hypersensitivity to orthopedic devices is a rare condition with an underestimated incidence due to the lack of diagnostic guideline and ambiguous clinical manifestations. Although hypersensitivity to metal is common, a few cases of hypersensitivity reactions have been reported after spinal instrumentation. Spinal fusion and stabilization require a wide range of devices such as screws, wires, bands, and artificial disk replacement devices. Spinal instrumented surgeries are different from total joint arthroplasty in several aspects such as degree and pattern of motion, loading environment, and adjacent tissues with distinct characteristics. The interval for hypersensitivity reactions to occur after spinal metallic implantation is usually weeks to months. The present review covers the topic of hypersensitivity reactions that have been reported after spinal surgeries with the focus on cutaneous presentations.

Neurological emergency from rare spinal metalloma: Case report and literature review

Metallosis is a rare and poorly understood long-term complication of instrumented surgery that can result in an inflammatory pseudotumor termed metalloma. We describe a particularly unique case and compare it to 6 analogous cases identified by PubMed and/or Medline search through July 2020. A 79-year-old male with multiple prior spinal lumbar fusion procedures presented with progressive weakness and pain. Imaging revealed a large mass surrounding the right-sided paraspinal rod with extension into the spinal canal, neural foramina, extraforaminal spaces, psoas muscle, marrow spaces, and right sided pedicles. The case presented is a unique example of a unilateral metalloma with mixed-metal instrumentation that created a progressive neurologic deficit without infection, pseudoarthrosis, or hardware failure. This case highlights the lack of understanding regarding the pathophysiology of metallosis and metalloma in spinal instrumentation. We highlight the imaging findings of metalloma to encourage early identification for removal and decompression.

Metal allergy hypersensitivity after posterior thoracic spinal fusion: A case report and review of the literature

Background:

Spine surgeons rarely consider metal allergies when placing hardware, as implants are thought to be inert.

Case Description:

A 32-year-old male presented with a skin rash attributed to the trace metal in his spinal fusion instrumentation. Patch testing revealed sensitivities to cobalt, manganese, and chromium. He underwent hardware removal and replacement with constructs of commercially pure titanium. His skin findings resolved at 2 weeks after surgery and were stable at 6 weeks.

Conclusion:

Hypersensitivity to metal (i.e., metal allergy) should be considered before performing instrumented spinal fusions.

Posterior Lumbar Facet Replacement and Arthroplasty

There is an ongoing desire for the development of motion-preserving facet replacement devices as an alternative to rigid fixation in hopes of better preserving the natural kinematics of the lumbar spine. Theoretically, such a construct would simultaneously address pain associated with spinal instability and prevent abnormal load distribution and adjacent segment degeneration. Several such devices have been developed including the Anatomic Facet Replacement System, the Total Facet Arthroplasty System, and the Total Posterior Arthroplasty System. Of these devices, none have yet proven to be more efficacious than rigid fixation for lumbar spinal stenosis, and studies are ongoing.

Hypersensitivity in patients receiving metal implants: a scoping review protocol

OBJECTIVE

The objective of this scoping review is to gather the available evidence on metal hypersensitivity to determine the extent of the problem and identify gaps in the evidence about screening practices.

INTRODUCTION

Hypersensitivity to metal was first reported in 1966. Since this time, the use of metal in prosthetic devices has increased with an associated rise in reported hypersensitivity reaction to other metals. Symptoms of metal hypersensitivity can be subtle, and it is unclear whether clinicians are aware of or routinely ask patients about metal hypersensitivity when documenting allergies. This can lead to a delay in diagnosis, which puts patients at risk of poor outcomes. Hence, there is a need to map the available evidence on hypersensitivity reaction in people who receive metallic device implantation.

INCLUSION CRITERIA

The review will consider studies that include patients who undergo procedures involving metal implantation. The concept to be explored is hypersensitivity following a procedure that involves the implementation of a device with metal components. Implementation is defined as permanent integration of a foreign (non-biological) object into the human body to restore function.

METHODS

The proposed scoping review will be conducted in accordance with JBI methodology for scoping reviews. Searches will be generated in multiple databases and updated as needed. Gray literature and organizational websites will also be searched. Titles, abstracts, and full articles will be screened according to the inclusion criteria. Studies published in English from 1960 to the present will be included. Data will be extracted and findings will be presented in tabular form with a narrative summary.

Metal Hypersensitivity in Joint Arthroplasty

Metal hypersensitivity in joint arthroplasty is a very controversial topic with limited evidence. With increasing numbers of joint replacements being done annually, a clear understanding of the pathogenesis, clinical picture, preimplant screening, postimplant workup, and treatment plan is crucial. This review article looked at all the available evidence regarding metal hypersensitivity and summarized the key findings. An algorithm was also proposed for preimplant screening, postimplant workup, and management.

Metal hypersensitivity screening among frontline healthcare workers-A descriptive study

AIMS AND OBJECTIVES

The study aims were to (a) assess allergy screening practices, (b) determine the awareness of metal hypersensitivity among frontline healthcare workers and (c) examine perceived barriers to implementing metal hypersensitivity screening into clinical practice.

BACKGROUND

Adverse device-related events, such as hypersensitivity to metals, are well documented in the literature. Hypersensitivity to metal is a type IV T-cell-mediated reaction that can occur after cardiac, orthopaedic, dental, gynaecological and neurosurgical procedures where a device with metal components is implanted into the body. Patients with hypersensitivity to metal are likely to experience delayed healing, implant failure and stent restenosis. Identifying patients with a history of metal hypersensitivity reaction could mitigate the risk of poor outcomes following device implant. Yet in clinical practice, healthcare workers do not routinely ask about the history of metal hypersensitivity when documenting allergies. The existing literature does not report why this is not included in allergy assessment.

DESIGN

Following the STROBE checklist, a cross-sectional, descriptive study was conducted.

METHODS

Frontline healthcare workers were recruited using professional contacts and social online media to complete an online questionnaire. Quantitative data were summarised descriptively while thematic analysis was used to examine barriers to implementation.

RESULTS

Three hundred forty-five participants from 14 countries completed the questionnaire, with the majority (187/54%) practicing in Canada, in general medicine and intensive care units. Ninety per cent of the participants did not routinely ask about metal hypersensitivity when evaluating allergy history. Of the respondents, 86% were unaware of the association between metal hypersensitivity and poor patient outcomes. After presented with the evidence, 81% indicated they were likely or very likely to incorporate the evidence into their clinical practice. Common themes about barriers to implementing were 'Standards of Practice', 'Knowledge' and 'Futility of Screening'.

CONCLUSION

The findings suggest lack of awareness as the main reason for not including metal in routine allergy assessment.

Facet Joint Replacement: Intermediate- and Long-Term Outcome in a Large Case Series

BACKGROUND

 The long-term outcome of facet joint replacement (FJR) still is to be proven.

METHODS

 We present a prospective case series of 26 (male-to-female ratio of 1:1; mean age: 61 years) patients undergoing FJR with a follow-up of at least 1 year (range: 12-112; mean: 67 months). Visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and the 12-Item Short Form Health Survey (SF-12) were applied pre- and postoperatively (after 3, 6, and 12 months) as well as at the last follow-up (N = 24). Using X-rays of the lumbar spine (N = 20), the range of motion (ROM) and disk height in the indicator and adjacent levels were assessed.

RESULTS

 FJR was performed at L3/L4 (N = 7), L4/L5 (N = 17), and L5/S1 (N = 2). Mean VAS (mm) for back pain decreased from 71 to 18, mean VAS for right leg pain from 61 to 7, and from 51 to 3 for the left leg. Mean ODI dropped from 51 to 22% (for all p < 0.01). Eighty seven percent of patients were satisfied and pretreatment activities were completely regained in 78.3% of patients. Disk height at the indicator and adjacent levels and ROM at the indicator segment and the entire lumbar spine were preserved. No loosening of implants was observed. Explantation of FJR and subsequent fusion had to be performed in four cases (15.4%).

CONCLUSIONS

 In selected cases, long-term results of FJR show good outcome concerning pain, quality of life, preservation of lumbar spine motion, and protection of adjacent level.

A rare case of delayed hypersensitivity reaction to metal ions secondary to a remnant pedicle screw fragment after spinal arthrodesis

Delayed hypersensitivity reaction to metal ions is rare and has been mostly documented among patients undergoing total joint arthroplasty with metal-on-metal bearing surfaces. Nonetheless, to our knowledge, only a few cases associated with spinal arthrodesis have been reported in the literature. The aim of this case report was to describe the clinical features of a rare case of delayed-type hypersensitivity reaction to nickel that occurred after an extraordinarily long period of time (approximately 15 years) after spinal arthrodesis. Here, we present a 38-year-old patient who was referred to us with a diagnosis of delayed-type hypersensitivity reaction to nickel that was established by a skin patch test. The chief sign and symptoms of the patient were allergic contact dermatitis along with intractable, generalized itching that started several months ago. The medical history revealed that the patient had undergone spinal arthrodesis using rods and pedicle screws approximately 15 years ago, followed by revision surgery to remove the implants. Radiological examination showed a remnant pedicle screw fragment at the third lumbar vertebra that had broken off during the removal of implants nine years ago. However, the signs and symptoms of metal hypersensitivity started shortly before the patient was referred to our hospital. We decided to remove the screw fragment as allergic contact dermatitis was refractory to medical treatment. On postoperative day one, the itching was completely resolved, although the skin patch test remained positive.