Selective versus routine patch metal allergy testing to select bar material for the Nuss procedure in 932 patients over 10years

Metal Hypersensitivity after Nuss Procedure: What and When to do?

Metal hypersensitivity after Nuss procedure is a known complication, but there is no accepted treatment guideline available. Patients undergoing Nuss procedure between 2013 and 2023 were examined retrospectively. Patients with known allergy, positive blood, and/or culture tests, and redo cases were excluded. Nine of 307 (2.9%) patients developed postoperative allergy. No significant difference was found between single or double bar patients. All were treated with medical protocol. No premature bar removal was necessitated. Medical treatment was successful in postoperative metal allergy after Nuss procedure. Ruling out other causes like surgical technical problems or infections is necessary for correct diagnosis and accurate treatment.

Chest Wall Dermatitis Patterns Following Thoracoscopic Intercostal Nerve Cryoablation for Surgical Correction of Pectus Excavatum

BACKGROUND

Intercostal nerve cryoablation (INC) has been shown to reduce postoperative pain and length of stay following surgical correction of pectus excavatum (SCOPE). Some patients have developed chest wall dermatological symptoms after INC that can be mistaken for metal allergy or infection. The purpose of this study is to report the symptoms, severity, incidence, and treatment of post-cryoablation dermatitis.

METHODS

A retrospective single institution review was performed for patients who underwent SCOPE with and without INC between June 2016 and March 2023 to assess for incidence of postoperative dermatological findings. Characteristics associated with these findings were evaluated.

RESULTS

During study period, 383 patients underwent SCOPE, 165 (43.1%) without INC and 218 (56.9%) with. Twenty-three (10.6%) patients who received INC developed exanthems characteristic of post-cryoablation dermatitis with two distinct phenotypes identified. No patients who underwent SCOPE without INC developed similar manifestations. Early dermatitis, characterized by a painless, erythematous, and blanching rash across the anterior thorax, was observed in 16 patients, presenting on median postoperative day 6.0 [IQR 6.0-8.5], with median time to resolution of 23.0 [IQR 12-71.0] days after symptom onset. Late dermatitis, characterized by hyperpigmentation spanning the anterior thorax, was observed in 7 patients, presenting on median postoperative day 129.0 [IQR 84.5-240.0], with median time to resolution of 114.0 [IQR 48.0-314.3] days.

CONCLUSION

This is the first report of dermatological manifestations following SCOPE with INC, a phenomenon of unknown etiology and no known long-term sequela. In our experience, it is self-resolving and lacks systemic symptoms suggesting observation alone is sufficient for resolution.

LEVEL OF EVIDENCE

IV.

Preoperative Metal Allergy Testing for Pectus Excavatum Repair Does Not Effectively Identify Patients Who Develop Metal bar Allergy

BACKGROUND

Metal allergy following placement of a metal pectus bar for minimally invasive repair of pectus excavatum (MIRPE) is a rare complication with potentially significant morbidity. There is no consensus regarding preoperative metal allergy testing (MAT). This study aims to assess incidence of metal allergy and titanium bar use in tested and untested patients and trends in MAT with different approaches to MAT.

METHODS

A retrospective chart review was performed on patients who underwent MIRPE from July 2009 to June 2022 at a single institution. During this time, MAT was performed routinely (RT; routine testing) and selectively (ST; selective testing).

RESULTS

The cohort included 741 patients for analysis. Metal bar allergy was documented in 1.3 % of all patients; the incidence was 1.3 % in patients with MAT and 1.4 % without MAT. The incidence of bar allergy was 1.1 % in the RT group and 1.6 % in the ST group. In the RT group, bar allergy occurred in 1.4 % (3/216) of patients with a negative MAT. In the ST group, bar allergy occurred in 1.2 % (2/164) of patients with a negative MAT and in 1.9 % (3/162) of untested patients with a stainless-steel bar. Titanium bar use was not significantly different between the RT and ST groups (18.3 % vs 16.3 %, p > 0.05).

CONCLUSION

The incidence of metal bar allergy after MIRPE was less than 2 %, and titanium bar use was not significantly different in routine and selective testing groups. MAT was not associated with a reduction in bar allergy, and its use remains unsupported.

LEVEL OF EVIDENCE

III.

Titanium nitride coating of pectus bar increases metal contamination after minimally-invasive repair of pectus excavatum

INTRODUCTION

Previous studies demonstrated a release of toxic metals, e.g. nickel and chromium, from stainless steel bars used for minimally invasive repair of pectus excavatum (MIRPE). In the present study, we investigated the impact of titanium nitride coating on the metal release and exposure of MIRPE patients.

MATERIAL AND METHODS

We analyzed the courses of nickel and chromium levels in blood, urine and local tissue in patients undergoing MIRPE with a titanium nitride coated pectus bar between 03/2017 and 10/2018. Sample collection was scheduled prior to MIRPE, at defined postoperative time points and at bar removal. Additionally, we evaluated irritative symptoms. Results were compared to a control group who received uncoated stainless steel bars in a previous time period (03/2015-02/2017).

RESULTS

12 patients received coated pectus bars (mean age 15.7 years). The control group included 28 patients. After implantation of a titanium nitride coated bar, significant increase in systemic nickel and chromium levels after one, two and three years was noted. In an interim analysis one year after MIRPE, we observed patients with coated bars to have significantly elevated trace metal values compared to the control group. This elevation persisted throughout the observation period. Tissue metal values were also significantly increased. Irritative symptoms occurred significantly more often in study patients compared to controls (50.0% vs. 14.3%).

CONCLUSIONS

Coating of pectus bars with titanium nitride failed to reduce metal contamination after MIRPE. Instead, it resulted in a significant increase of trace metal levels after MIRPE, compared to patients with stainless steel bars, which may be explained by wear of the coating and inter-component mobilization processes.

Preoperative Metal Patch Testing and Titanium Bar Use Criteria in Nuss Procedure: A 56-Patients' Cohort Study

INTRODUCTION

 Nuss procedure is the main reason for metal implants use by pediatric and thoracic surgeons. There is an ongoing debate on how to avoid allergic complications. Herein we describe our 8-year experience with systematic preoperative metal patch testing and our selective titanium bar use in Nuss procedure.

MATERIALS AND METHODS

 This is a single center retrospective observational cohort study of patients who underwent the Nuss procedure from 2013 to 2020. Preoperative metal patch testing was done in all cases. Criteria for titanium bar utilization were: a positive test for a major component of the stainless-steel bar; or a positive metal patch test and a positive history of atopy, food or metal allergy, or previous allergic reaction to an implant or device.

RESULTS

 In total, 56 patients were included. Most were male (91.1%) with a median age of 15.0 (13.0-22.0) years old. 19.6% had a positive preoperative metal patch test and 54.5% of these had no personal history of atopy. Stainless-steel bars were used in 27.3% of those patients and titanium bars were used in 72.7%. One patient had a documented minor allergy reaction. None of the 56 patients required early bar removal.

CONCLUSION

 Our study suggests that routine preoperative allergy testing and a judicious use of titanium bar are safe and avoid metal allergic complications.

Nickel contamination after minimally-invasive repair of pectus excavatum persists after bar removal

BACKGROUND

Minimally-invasive repair of pectus excavatum (MIRPE) has been shown to be associated with high release of trace metals into patient's body. The aim of our study was to analyze the kinetics of metal contamination after MIRPE and after bar removal.

METHODS

We prospectively assessed nickel and chromium changes in blood, urine, and local tissue in patients undergoing MIRPE with stainless-steel bar(s). Baseline samples were taken prior to surgery, further samples were taken at six defined time points until 30 months after bar removal. Clinical symptoms were evaluated at the time of every sample collection.

RESULTS

28 patients were included (mean age 16.4 years). At four weeks after MIRPE and persisting up to bar removal, we found significantly elevated trace metal levels in blood and urine. Tissue nickel and chromium levels were significantly elevated at the time of bar removal. After bar removal, the concentration of trace metal in urine and the concentration of chromium in plasma decreased gradually. In contrast, nickel levels in blood further increased. Five patients showed irritative symptoms after MIRPE, all symptomatic patients had elevated metal levels.

CONCLUSIONS

Following MIRPE, we found a rapid systemic increase of nickel and chromium. Our data indicate that trace metal release could cause irritative symptoms. The prolonged elevated systemic nickel levels beyond bar removal necessitate further investigations of the long-term side effects of MIRPE.

Current Development of Minimally Invasive Repair of Pectus Excavatum (MIRPE)

For decades, open surgical repair was the only available method to treat congenital and acquired chest wall deformities (CWDs). In 1998, D. Nuss described a minimally invasive procedure for surgical repair of Pectus excavatum (PE). Today, the Nuss procedure is performed with increasing frequency worldwide and considered as the “gold standard”. After its introduction, the method experienced numerous modifications such as routine thoracoscopy and/or sternal elevation, increasing safety of the procedure. Placement of multiple bars and/or the so called cross-bar technique were introduced to correct complex CWDs. Standardized pain management, the introduction of cryo-analgesia and a standardized postoperative physiotherapy program including deep breathing exercises facilitate the establishment of an enhanced recovery after surgery (ERAS) process. However, the widespread use of the minimally invasive repair of pectus excavatum (MIRPE) procedure has been associated with a significant number of serious complications. Furthermore, several studies report near-fatal complications, not only during bar placement, but also during bar removal. This review focuses upon the most relevant modifications, including recent published surgical techniques of MIRPE, in order to describe current developments in the field.

Utility of routine patch testing prior to surgical repair of pectus excavatum: A multidisciplinary experience via retrospective review at a single tertiary care center

BACKGROUND

The Nuss procedure is the only implant procedure in which routine, rather than selective, preoperative patch testing is recommended. This practice has recently been called into question.

OBJECTIVE

To evaluate an updated experience of pre-implant patch testing in patients undergoing the Nuss procedure.

METHODS

A retrospective chart review of Nuss procedures from 2012 through 2020.

RESULTS

Forty-five patients were identified for data collection. From 2012 to 2014, none of the 14 patients were patch tested. From 2015 to 2020, 26 of 31 (83.9%) were patch tested. Of those tested, only 2 had a positive patch test. A hypoallergenic titanium bar was inserted in each case. In total, there were zero bar reactions.

CONCLUSION

The risks of patch testing are extremely small and should be weighed against the serious implications of even one bar allergy when deciding on future guidelines.

Case series of metal allergy following Nuss procedure: Not only for stainless steel bars

BACKGROUND

Pectus excavatum is often managed with the Nuss procedure. Metal allergies to pectus bars occur in 5% of patients, though pre-operative testing is not generally routine.

OBJECTIVES

This study describes our experience with pre-operative metal allergy testing and post-operative allergic reactions to pectus bars.

METHODS

A retrospective study of patients who underwent a Nuss procedure at our institution from 2010-2020 was performed. Patients with documented "metal" allergy, defined by the need for and positive response to steroid treatment and the absence of infection, were included. Data on patient characteristics and clinical course were analyzed.

RESULTS

Five of 204 patients (2.5%) identified developed allergic metal reactions. Three of five patients developed allergic reactions to titanium bars, with two requiring early removal of the bar (< 2-3 years). Four patients required more than one course of steroids, and three required debridements for skin breakdown. All patients have maintained good surgical correction at one- and three-years post removal.

CONCLUSIONS

Pectus bar metal allergies occur with both stainless steel and titanium bars. Properly selected patients for pre-operative Finn^Ⓡ Chamber testing may reduce the overall incidence of stainless-steel allergies but may miss titanium bar allergies. Early recognition and treatment of bar allergies may salvage the bar and avoid premature removal.

Blood metal levels after minimally invasive repair of pectus excavatum

 

OBJECTIVES

Minimally invasive repair of pectus excavatum (MIRPE) is the most popular surgical approach for paediatric patients with pectus excavatum. A substernal stainless still bar is inserted and left in place for 3 years and then removed. Our goal was to investigate blood metal levels after MIRPE and to correlate them with surgical details, such as the numbers of bars and stabilizers and the length of time the bar was in place.

METHODS

Blood levels of iron, chromium, manganese, molybdenum and nickel were analysed in 130 teenagers (108 boys and 22 girls) who had MIRPE using inductively coupled plasma mass spectrometry. A total of 62 patients were operated on using MIRPE (study group) and 68 patients were evaluated at implant time (control group). Differences between the numbers of bars implanted and the presence or absence of stabilizers were also considered.

RESULTS

Significant increases in the levels of abnormal chromium were found in patients in the study group compared with the controls (P = 0.02). When we compared the group of patients with 2 or more bars with the group with 1 bar, the percentage of patients with a value above the threshold increased by 29 (P = 0.05). A significant increase in chromium levels was observed in patients with stabilizers (P = 0.03). Above-threshold levels of molybdenum were found in 5.1% of patients in the control group, but the number was not statistically significant (P = 0.09).

CONCLUSIONS

We demonstrated that stainless steel devices used in MIRPE can elevate blood metal levels in paediatric patients. Moreover, we demonstrated that the use of metal stabilizers is associated with higher metal levels, probably due to increased dispersion.

Metal allergy after the Nuss procedure for pectus excavatum: a review

Minimally invasive repair of pectus excavatum (MIRPE) technique (the Nuss procedure) is a minimally-invasive method that is commonly used in the treatment of pectus excavatum. An allergic reaction to the metal alloy bar that is implanted in the thorax during the procedure is a reported complication. We briefly review current literature concerning epidemiology, mechanisms and research results of allergic reactions after Nuss bar implantation. This allergic reaction occurs in approximately 2.7% of patients and is caused by metals used in the medical implant. The most common symptoms include fever and skin lesions such as allergic dermatitis. Elevated levels of C-reactive protein is a frequent finding in laboratory tests. In order to minimize the risk of such complications, taking a detailed allergy-based medical history and conducting allergy tests, i.e. patch test are required. Allergic reactions can be managed with conservative treatment such as general or topical glucocorticosteroid therapy and antihistamine agents. Severe allergic reactions can be addressed by implant revision, replacement of the steel bar with a titanium substitute or removal of the stabilization at all. Although the risk of an allergic reaction to titanium is smaller it still exists, the titanium substitute is not routinely used due to its higher cost and lesser plasticity which has a negative impact on matching a stabilizing bar during the surgery. Surgeons treating pectus excavatum should remember about the possible allergic reactions after implantation of the metal bar and be familiar with methods of diagnosis and treatment of those complications.