From fossil to bio‐circular plastics: the environmental benefits of bio‐attributed acrylonitrile butadiene styrene in single‐use cystoscopes

Abstract

Background

Single‐use cystoscopes are increasingly adopted in urology, but concerns regarding their environmental footprint persist. Substituting conventional fossil‐based plastics with bio‐attributed materials may reduce life cycle impacts, yet the magnitude and robustness of this benefit remain uncertain.

Objective

To evaluate the environmental performance of a single‐use flexible cystoscope (aScope™ 4 Cysto; Ambu A/S, Copenhagen, Denmark) incorporating bio‐attributed acrylonitrile butadiene styrene (Bio‐ABS) using a cradle‐to‐grave life cycle assessment (LCA).

Methods

An attributional LCA was performed according to the International Organization for Standardization (ISO) 14040/44 standards, investigating the impact of the introduction of Bio‐ABS (50:50 mass balance with fossil feedstock). The functional unit was one cystoscopy procedure. System boundaries included raw material extraction, manufacturing and sterilisation, packaging, distribution, use, and end‐of‐life treatment. Two geographic scenarios were evaluated (UK and USA). Climate change (kg CO₂ equivalents [kg CO₂ eq.]) was the primary impact category, with others including human toxicity, particulate matter, and resource use. Sensitivity analyses assessed alternative allocations for bio‐circular feedstock and variations in sterilisation utilities.

Results

The total carbon footprint of the cystoscope decreased from 1.63 to 1.46 kg CO₂ eq. (USA) and from 1.74 to 1.61 kg CO₂ eq. (UK) with Bio‐ABS, corresponding to reductions of 10% and 7.5%, respectively. Raw material production and sterilisation were the dominant contributors (55–60% of total impact), with packaging accounting for 22–24%. Component‐level analysis showed plastics as the primary driver of climate impacts, while electronics and metals contributed disproportionately to resource use and toxicity categories. Sensitivity analyses confirmed the robustness of the Bio‐ABS benefit, even when environmental burdens were assigned to bio‐feedstock.

Conclusions

Incorporating bio‐attributed plastics into single‐use cystoscopes yields a consistent reduction in life cycle carbon footprint. While material substitution provides measurable benefits, packaging redesign and optimised logistics represent additional opportunities for environmental impact reduction. These findings inform sustainable endoscopic practice and highlight the importance of transparent life cycle modelling in medical device evaluation.

Abbreviations

(Bio‐)ABS

(bio‐attributed) acrylonitrile butadiene styrene

eq.

equivalent

EF

Environmental Footprint

EoL

end‐of‐life

ISCC

International Sustainability and Carbon Certification

ISO

International Organization for Standardization

LCA

life cycle assessment

LCI

life cycle inventory

LCIA

life cycle impact assessment

PCB

printed circuit board

PEF

Product Environmental Footprint

Introduction

Healthcare systems are under increasing pressure to reduce their environmental footprint, with operating theatres and endoscopic practice identified as major contributors to healthcare‐related emissions [1]. In urology, the growing use of single‐use devices has raised concerns regarding sustainability but also offered opportunities for innovation [2].

The environmental performance of reusable vs single‐use endoscopic devices remains actively debated and appears highly dependent on contextual factors such as local electricity mix, reprocessing practices, transport logistics, consumable use, and waste management infrastructure [3]. While several life cycle assessments (LCAs) have reported lower impacts for single‐use devices in specific healthcare settings, more recent studies suggest that optimisation of reusable device reprocessing may substantially improve their environmental performance [4].

In 2023, we published a LCA comparing reusable and single‐use cystoscopes [5]. Contrary to common assumptions, our analysis demonstrated that in the studied context, single‐use cystoscopes had a lower environmental impact across multiple categories including carbon footprint. Importantly, production and packaging of the disposable device were identified as the major environmental hotspots, highlighting the need for material innovation.

Since then, the manufacturer has replaced the conventional 100% fossil‐based acrylonitrile butadiene styrene (ABS) with bio‐attributed ABS (Bio‐ABS). This new material introduces a partial substitution of fossil feedstock with bio‐circular sources such as used cooking oil, forestry residues, or other organic waste streams. These waste‐derived inputs are converted into the same polymer structure as fossil‐based ABS, meaning that the resulting plastic is chemically identical and functionally indistinguishable from its conventional counterpart. The only difference lies in the origin of the carbon used, enabling potential reductions in life cycle emissions without altering device performance or clinical usability.

Therefore, a LCA was performed to evaluate the environmental performance of this ‘new generation’ cystoscope incorporating Bio‐ABS.

Methods

Study Design

This study was conducted as an attributional LCA comparing two material configurations of a single‐use flexible cystoscope: a conventional version manufactured using 100% fossil‐based ABS and a revised version incorporating Bio‐ABS. The analysis followed the principles and framework set out in the International Organization for Standardization (ISO) 14040:2006 and ISO 14044:2006 standards [6, 7]. The LCA was performed independently by FORCE Technology (Brøndby, Denmark) in 2025.

Goal and Scope

The main goal of the study was to quantify the environmental performance of a single‐use flexible cystoscope after the introduction of bio‐attributed ABS.

The intended audience includes clinicians, healthcare decision‐makers, medical device manufacturers, and researchers interested in sustainable healthcare technologies. The results are intended to support comparative environmental assessment and inform material selection strategies in urological endoscopy.

Functional Unit

The functional unit was defined as one cystoscopy procedure performed on one patient. The functional unit reflects the clinical use of the device and allows comparison across healthcare settings.

System Boundaries

A cradle‐to‐grave system boundary was applied, encompassing all life cycle stages from raw material extraction through manufacturing, sterilisation, packaging, distribution, use, and end‐of‐life (EoL) treatment. The following processes were included: (i) Extraction and processing of raw materials, (ii) Polymer production and component manufacturing, (iii) Device assembly and sterilisation, (iv) Primary and secondary packaging, (v) Distribution to healthcare facilities, (vi) Use phase, and (vii) EoL treatment. The system does not consider any capital goods, maintenance requirements, loss of materials during transportation, packaging used between supplier and manufacturing facility or manufacturing waste during assembly of the endoscopes.

Two geographic scenarios were modelled to reflect differences in electricity mixes, transport distances, and waste management systems: UK and USA. A schematic representation of the system boundaries is provided in Fig. 1.

Fig. 1.

System boundaries of the endoscope considered in this LCA study. Green arrow indicates materials sent for recycling including transportation to a recycling facility where it is sorted, washed and made ready to leave end‐of‐waste state. Red arrow indicates materials sent for incineration including transportation to incineration facility. EtO, ethylene oxide gas (used in sterilisation); PP, polypropylene.

Description of the Device

The analysed device was the aScope™ 4 Cysto (Ambu A/S, Copenhagen, Denmark), a single‐use flexible cystoscope intended for diagnostic and therapeutic urological procedures. The device is supplied sterile and designed for one‐time clinical use.

The study focused exclusively on the impact of substituting fossil‐based ABS with bio‐ABS in selected plastic components, primarily the handle of the cystoscope, while all other components and materials remained unchanged between scenarios.

Life Cycle Inventory (LCI)

Primary foreground data relating to material composition, manufacturing processes, energy use, packaging, and sterilisation were provided by the manufacturer (Ambu A/S). Electronic components, including the camera and light‐emitting diode (LED) system, were modelled primarily through printed circuit board (PCB) datasets obtained from Sphera MLC 2024 and Ecoinvent version 3.10 databases. Metallic constituents such as copper were aggregated within the broader metal inventory. Data completeness and consistency were reviewed by FORCE Technology. Background (secondary) data were sourced from the Managed LCA Content (MLC) (Sphera 2024) and Ecoinvent version 3.10. Life cycle modelling was conducted using LCA for Experts software. The study is an attributional LCA, using average inventory data and only concerning the unit processes within the life cycle of the system. When secondary data on a specific process was not found in the databases, proxies with similar or generic processes were established representing the technological scope as best as possible. Details regarding the LCI can be found in Appendix S1.

Modelling of Bio‐ABS

Bio‐ABS is certified under the mass balance chain of custody model, and in accordance with International Sustainability and Carbon Certification (ISCC) PLUS requirements. The resulting polymer is chemically identical to conventional ABS and indistinguishable in terms of mechanical properties and performance. The bio‐attributed ABS used in this study was modelled as a 50:50 mix of fossil‐based and bio‐circular feedstock.

Bio‐circular feedstocks included waste‐derived and residual materials such as:

• Used cooking oil

• Kitchen waste

• Crude tall oil

• Low‐value forestry residues

These feedstocks were treated as burden free in the baseline scenario, consistent with common LCA practice for waste and residue streams. The exact proportional composition of individual bio‐circular feedstocks within the mass‐balance system is not disclosed by upstream suppliers and was therefore not available for inclusion in the LCI. However, the impact of the modelling choice was assessed in a sensitivity analysis.

Allocation Procedures and EoL Modelling

Allocation was conducted in accordance with ISO 14040:2006 and ISO 14044:2006 standards. Recycling was modelled using the cut‐off approach to avoid double counting of environmental burdens and benefits. Under this approach, waste‐derived feedstocks used for the production of Bio‐ABS (including used cooking oil, kitchen waste, and crude tall oil) were treated as burden free in the baseline scenario. The same approach was applied to the recycling of polypropylene and paper and cardboard packaging materials, with recycling processes modelled up to the end‐of‐waste state and no credits assigned for substitution of virgin materials.

The EoL incineration was modelled with energy recovery. Credits associated with the generation of electricity and thermal energy were included through system expansion, assuming substitution of the average electricity grid mix and natural gas in the UK and USA, respectively. Losses during recycling and incineration were accounted for using secondary datasets. More information regarding the life cycle stages, modelling choices, and key assumptions can be found in Appendix S2.

Cut‐Off Criteria

In accordance with ISO 14040:2006 and ISO 14044:2006, all relevant processes and material and energy flows attributable to the analysed system were included wherever possible. For practical reasons, material or energy flows contributing <1% to the total mass or energy of the system were eligible for exclusion when representative data were unavailable, provided that the cumulative contribution of excluded flows did not exceed 5% of the total.

Accordingly, a minor quantity of ink used for the handle top component was excluded from the analysis, as it represented <0.01% of the component mass and no suitable LCI dataset was available. While some bio‐circular feedstocks (e.g., crude tall oil) may have commercial value, they were treated consistently under the cut‐off approach in accordance with supplier certification; the implications of this assumption are addressed in the Discussion.

Life Cycle Impact Assessment (LCIA)

The overall method of the LCA is attributional (LCIA), meaning it estimates what share of the global environmental burdens are attributed to the products. The LCIA method applied is from the European Union (EU) Product Environmental Footprint (PEF) methodology, namely Environmental Footprint (EF) 3.1 method, which quantifies the 16 environmental impact categories as listed in Table 1. The characterised results are normalised to Person Equivalents (PE) via EF 3.1 using normalisation factors [8]. Thereby the CO₂ equivalents (CO₂ eq.), as an example, are expressed as a contribution to the average global emissions of greenhouse gas (GHG) per person per year with 2019 as reference [8].

Table 1.

Impact categories used in the LCIA, including the associated indicators, units, underlying methodological models, and scientific definitions. Source: Environmental Footprint 3.1 from the Joint Research Centre – European Commission (found at: https://eplca.jrc.ec.europa.eu/LCDN/developerEF.html).

Impact category	Indicator	Unit	Scientific definition	Underlying LCIA method
Acidification	Accumulated exceedance (AE)	mol.H+ eq.	Represents the potential of acidifying substances to alter soil and freshwater pH, damaging ecosystems	AE [9, 10]
Climate change	Radiative forcing as Global Warming Potential (GWP100)	kg.CO2 eq.	Measures the cumulative radiative forcing of greenhouse gases over 100 years, expressed as CO2 equivalents	Bern model – GWP over a 100‐year time horizon based on IPCC 2021 [11]
Biogenic
Fossil
Land use and land use change
Ecotoxicity, freshwater	Comparative toxic unit for ecosystems (CTUe)	CTUe	Evaluates potential harm to aquatic ecosystems caused by chemical emissions	Based on USEtox2.1 model [12, 13], adapted as in Saouter et al. [14]
Eutrophication, freshwater	Fraction of nutrients reaching freshwater end compartment (P)	kg.P eq.	Quantifies phosphorus emissions leading to algal blooms and oxygen depletion in freshwater bodies	EUTREND model [15] as implemented in ReCiPe 2008
Eutrophication, marine	Fraction of nutrients reaching marine end compartment (N)	kg.N eq.	Estimates nitrogen emissions that contribute to eutrophication and hypoxic zones in marine environments	EUTREND model [15] as implemented in ReCiPe 2008
Eutrophication, terrestrial	Accumulated exceedance (AE)	mol.N eq.	Assesses nitrogen deposition to soils that may cause nutrient imbalance and biodiversity loss in terrestrial ecosystems	AE [9, 10]
Human toxicity, cancer	Comparative toxic unit for humans (CTUh)	CTUh	Estimates the cancer‐related health risks from exposure to toxic substances, expressed per unit of intake	Based on USEtox2.1 model [12, 13], as in Saouter et al. [14]
Human toxicity, non‐cancer	CTUh	CTUh	Estimates the non‐cancer health risks from exposure to toxic substances, expressed per unit of intake	Based on USEtox2.1 model [12, 13], as in Saouter et al. [14]
Ionising radiation, human health	Human exposure efficiency relative to U235	kBq.U235 eq.	Assesses health risks associated with human exposure to ionising radiation, normalised to U235	Human health effect model as developed by Dreicer et al. [16] and published in Frischknecht et al. [17]
Land use	Soil Quality Index	Dimensionless (points)	Measures the impact of land occupation and transformation on soil functions and quality	Soil Quality Index based on LANCA model [18] and on the LANCA CF version 2.5 [19]
Ozone depletion	Ozone depletion potential (ODP)	kg.CFC‐11 eq.	Estimates the potential of a substance to degrade the stratospheric ozone layer, relative to CFC‐11	EDIP model based on the ODPs of the World Meteorological Organisation (WMO) over an infinite time horizon (WMO 2014 + integrations)
Particulate matter	Human health effects associated with exposure to PM2.5	Disease incidences	Quantifies human morbidity and mortality linked to long‐term exposure to PM2.5	PM model [20]
Photochemical ozone formation, human health	Tropospheric ozone concentration increase	kg.NMVOC eq.	Estimates the increase in ground‐level ozone formation, caused by emissions of reactive volatile organic compounds	LOTOS‐EUROS model [21] as applied in ReCiPe 2008
Resource use, fossils	Use of fossil resources	MJ	Estimates the decrease in fossil fuels like coal, oil and gas, as extracting resources today will force future generations to extract less or different resources	van Oers et al. [22] as in CML 2002 method, v.4.8
Resource use, mineral and metals	Use of mineral and metals resources	kg.Sb eq.	Estimates the decrease in mineral and metals resources, as extracting resources today will force future generations to extract less or different resources	van Oers et al. [22] as in CML 2002 method, v.4.8
Water use	Use of water	m3.world eq.	Quantifies the ‘depletion’ of available water	Available WAter Remaining (AWARE) model [23]

CFC‐11, trichlorofluoromethane; CML Centrum voor Milieukunde Leiden; EDIP, Environmental Design of Industrial Products; EUTREND, Eutrophication Trend; IPCC, Intergovernmental Panel on Climate Change; LANCA, LANd use indicator value Calculation; LOTOS‐EUROS, Long Term Ozone Simulation‐European Operational Smog; NMVOC, non‐methane volatile organic compounds; PM2.5, fine particulate matter <2.5 μm; UNEP, United Nations Environment Programme; USEtox, UNEP/Society for Environmental Toxicology and Chemistry (SETAC) Toxicity model; v., version.

Climate change (kg CO₂ eq.) was defined as the primary impact category due to its relevance to healthcare decarbonisation strategies. Additional impact categories of interest included (not exhaustive) human toxicity, particulate matter formation, fossil resource use, and mineral and metal resource use.

Sensitivity Analyses

Sensitivity analyses were conducted to assess the robustness of the results to key modelling assumptions. In particular, an alternative scenario was modelled in which environmental burdens were attributed to the bio‐circular feedstock (e.g., used cooking oil) rather than treating it as burden free.

A relative difference exceeding 5% between scenarios was pre‐specified as indicative of a meaningful environmental change.

Funding and Role of the Sponsor

This study was financially supported by Ambu A/S. The sponsor had no role in the study design, data analysis, interpretation of results, or manuscript preparation. The LCA was conducted independently by FORCE Technology. The authors were responsible for interpretation of results and manuscript preparation.

Results

The total carbon footprint of the cystoscope was 1.46 kg CO₂ eq. in the USA scenario and 1.61 kg CO₂ eq. in the UK scenario. Across both contexts, raw material extraction and production (including sterilisation) remained the dominant contributors (55–60% of total impact), primarily driven by the use of plastics and the sterilisation process. Packaging accounted for an additional 22–24% of the footprint, largely from paper and cardboard materials. Contributions from distribution and EoL treatment varied across impact categories and between the UK and USA, without a consistent trend. Beyond climate change, four categories emerged as major contributors to the device's environmental profile: human toxicity (cancer), particulate matter, fossil resource use, and mineral and metal resource use (Table 2).

Table 2.

Total characterised results for device with EoL in USA or UK via EF 3.1.

Impact category (unit)	USA scenario						UK scenario
	Total	Raw materials and production*	Packaging*	Use	Distribution**	EoL***	Total	Raw materials and production*	Packaging*	Use	Distribution**	EoL***
Acidification (mole H+ eq.)	7.23E−03	3.33E−03	1.54E−03	0.00E+00	2.35E−03	1.54E−05	7.97E−03	3.33E−03	1.54E−03	0.00E+00	2.98E−03	1.26E−04
Climate change – total (kg CO2 eq.)	1.46E+00	8.80E−01	3.51E−01	0.00E+00	1.22E−01	1.05E−01	1.61E+00	8.80E−01	3.51E−01	0.00E+00	1.10E−01	2.69E−01
Climate change, biogenic (kg CO2 eq.)	6.43E−03	2.30E−03	3.26E−03	0.00E+00	4.49E−04	4.14E−04	2.26E−03	2.30E−03	3.26E−03	0.00E+00	3.20E−04	−3.62E−03
Climate change, fossil (kg CO2 eq.)	1.45E+00	8.77E−01	3.45E−01	0.00E+00	1.21E−01	1.04E−01	1.60E+00	8.77E−01	3.45E−01	0.00E+00	1.09E−01	2.72E−01
Climate change, land use and land use change (kg CO2 eq.)	4.35E−03	1.03E−03	2.48E−03	0.00E+00	8.47E−04	−1.15E−05	4.09E−03	1.03E−03	2.48E−03	0.00E+00	5.85E−04	−7.08E−06
Ecotoxicity, freshwater – total (CTUe)	9.20E+00	6.18E+00	2.52E+00	0.00E+00	1.23E+00	−7.32E−01	8.30E+00	6.18E+00	2.52E+00	0.00E+00	1.32E+00	−1.72E+00
Eutrophication, freshwater (kg P eq.)	1.40E−04	2.14E−05	7.17E−05	0.00E+00	5.22E−08	4.65E−05	1.40E−04	2.14E−05	7.17E−05	0.00E+00	3.57E−08	4.64E−05
Eutrophication, marine (kg N eq.)	2.25E−03	9.34E−04	5.03E−04	0.00E+00	7.24E−04	9.12E−05	2.31E−03	9.34E−04	5.03E−04	0.00E+00	7.80E−04	9.77E−05
Eutrophication, terrestrial (mole N eq.)	2.33E−02	1.02E−02	4.83E−03	0.00E+00	7.95E−03	3.62E−04	2.40E−02	1.02E−02	4.83E−03	0.00E+00	8.55E−03	4.03E−04
Human toxicity, cancer – total (CTUh)	5.86E−09	5.39E−09	4.50E−10	0.00E+00	2.00E−11	−1.86E−13	5.83E−09	5.39E−09	4.50E−10	0.00E+00	2.09E−11	−3.88E−11
Human toxicity, non‐cancer – total (CTUh)	1.40E−08	8.40E−09	3.76E−09	0.00E+00	4.10E−10	1.40E−09	1.23E−08	8.40E−09	3.76E−09	0.00E+00	4.25E−10	−2.60E−10
Ionising radiation, human health (kBq U235 eq.)	−6.09E−03	1.52E−02	2.01E−02	0.00E+00	1.29E−04	−4.15E−02	−1.52E−02	1.52E−02	2.01E−02	0.00E+00	2.73E−05	−5.06E−02
Land use (point)	3.40E+01	1.96E+00	3.13E+01	0.00E+00	5.11E−01	1.89E−01	3.30E+01	1.96E+00	3.13E+01	0.00E+00	3.52E−01	−6.49E−01
Ozone depletion (kg CFC‐11 eq.)	1.58E−08	9.05E−11	3.41E−09	0.00E+00	7.93E−15	1.23E−08	1.58E−08	9.05E−11	3.41E−09	0.00E+00	3.81E−15	1.23E−08
Particulate matter (disease incidences)	9.76E−08	3.01E−08	2.73E−08	0.00E+00	3.64E−08	3.87E−09	1.14E−07	3.01E−08	2.73E−08	0.00E+00	5.12E−08	5.12E−09
Photochemical ozone formation, human health (kg NMVOC eq.)	6.30E−03	2.82E−03	1.51E−03	0.00E+00	1.94E−03	3.82E−05	6.53E−03	2.82E−03	1.51E−03	0.00E+00	2.13E−03	7.08E−05
Resource use, fossils (MJ)	1.90E+01	1.48E+01	6.58E+00	0.00E+00	1.57E+00	−4.01E+00	2.06E+01	1.48E+01	6.58E+00	0.00E+00	1.37E+00	−2.22E+00
Resource use, mineral and metals (kg Sb eq.)	3.03E−05	2.93E−05	8.10E−07	0.00E+00	1.59E−08	1.36E−07	3.03E−05	2.93E−05	8.10E−07	0.00E+00	8.71E−09	1.20E−07
Water use (m3 world eq.)	2.43E−01	5.48E−02	1.94E−01	0.00E+00	4.50E−04	−5.38E−03	3.09E−01	5.48E−02	1.94E−01	0.00E+00	3.04E−04	6.00E−02

^*Including transportation of raw materials from supplier to manufacturer, processing materials into component. e.g., injection moulding.

^**Transportation from manufacturing gate to receiving hospital.

^***Including transportation.

CFC‐11, trichlorofluoromethane; CTUe, Comparative toxic unit for ecosystems; CTUh, comparative toxic unit for humans; NMVOC, non‐methane volatile organic compounds.

Contribution of Life Cycle Stages

When results were further disaggregated by individual life‐cycle elements, notable differences emerged (Fig. 2). Secondary packaging accounted for the largest share of impacts across most categories, while specific components dominated selected impact categories, such as resource use (minerals and metals), resource use (fossils), and human toxicity (cancer). These differences reflect variations in material composition across components.

Fig. 2.

Contribution to characterised impact scores using LCIA EF 3.1 for life cycle of the device with USA EoL scenario (top) and UK EoL scenario (bottom). For most endpoints, plastic and plastic packaging predominantly drive the environmental impact.

Transport to the hospital contributed substantially to several impact categories, most prominently particulate matter formation, with additional contributions to acidification, marine and terrestrial eutrophication, and photochemical ozone formation. Transport distances to the UK hospital were longer than to the USA, primarily due to current maritime routing around Africa. However, for several impact categories (climate change, freshwater eutrophication, ionising radiation, land use, ozone depletion, and resource use [fossil and minerals and metals]), distribution impacts were higher in the USA scenario. This difference was driven by a greater reliance on road and rail transport in the USA, which entails higher fuel consumption and land use per transported unit compared with maritime shipping.

No environmental impacts were attributed to the use phase, as the cystoscope is discarded after a single use without further processing. The EoL stage contributed most notably to ozone depletion and freshwater eutrophication, with differences observed between the USA and UK scenarios due to variations in waste incineration efficiencies and energy recovery. Overall, no consistent directional trend was observed across all impact categories when comparing EoL scenarios between the two geographical contexts.

The detailed contribution analysis (characterised impact results for individual materials) is shown in Appendix S3.

Sensitivity Analyses

Sensitivity analyses demonstrated that replacing 100% fossil feedstock ABS with Bio‐ABS reduced environmental impacts. For the main impact category of climate change, the carbon footprint decreased from 1.63 to 1.46 kg CO₂ eq. in the USA scenario and from 1.74 to 1.61 kg CO₂ eq. in the UK scenario, corresponding to a 10% reduction and 7.5% reduction, respectively, exceeding the 5% pre‐specified significant threshold (Fig. 3). Similar trends were observed across other impact categories, with bio‐attributed feedstock consistently yielding improved performance (Table 3).

Fig. 3.

Characterised climate change impacts via EF 3.1 between the Bio‐ABS scope (hereby Cysto) and the fossil‐based scope (hereby SC2, Scenario 2) with USA EoL scenario (left) and UK EoL scenario (right).

Table 3.

Scenario comparison for baseline results (Bio‐ABS) compared with the 100% fossil‐based plastic device (sensitivity analysis).

Impact category (unit)	USA scenario			UK scenario
	Baseline	Sensitivity analysis	Percentage change	Baseline	Sensitivity analysis	Percentage change
Acidification (mol H+ eq.)	7.23E−03	7.47E−03	3.2	7.97E−03	8.15E−03	2.2
Climate change – total (kg CO2 eq.)	1.46E+00	1.63E+00	10	1.61E+00	1.74E+00	7.5
Climate change, biogenic (kg CO2 eq.)	6.43E−03	6.77E−03	5.0	2.26E−03	2.63E−03	14
Climate change, fossil (kg CO2 eq.)	1.45E+00	1.62E+00	11	1.60E+00	1.73E+00	7.5
Climate change, land use and land use change (kg CO2 eq.)	4.35E−03	4.72E−03	7.8	4.09E−03	4.46E−03	8.3
Ecotoxicity, freshwater – total (CTUe)	9.20E+00	1.04E+01	12	8.30E+00	9.29E+00	11
Eutrophication, freshwater (kg P eq.)	1.40E−04	1.40E−04	0	1.40E−04	1.40E−04	0
Eutrophication, marine (kg N eq.)	2.25E−03	2.34E−03	3.8	2.31E−03	2.39E−03	3.3
Eutrophication, terrestrial (mol N eq.)	2.33E−02	2.42E−02	3.7	2.40E−02	2.47E−02	2.8
Human toxicity, cancer – total (CTUh)	5.86E−09	5.95E−09	1.5	5.83E−09	5.91E−09	1.4
Human toxicity, non‐cancer – total (CTUh)	1.40E−08	1.51E−08	7.3	1.23E−08	1.34E−08	8.2
Ionising radiation, human health (kBq U235 eq.)	−6.09E−03	2.74E−03	322	−1.52E−02	−1.29E−02	−18
Land use (point)	3.40E+01	3.42E+01	0.6	3.30E+01	3.31E+01	0.3
Ozone depletion (kg CFC‐11 eq.)	1.58E−08	1.58E−08	0	1.58E−08	1.58E−08	0
Particulate matter (disease incidences)	9.76E−08	9.95E−08	1.9	1.14E−07	1.15E−07	0.9
Photochemical ozone formation, human health (kg NMVOC eq.)	6.30E−03	6.56E−03	4.0	6.53E−03	6.74E−03	3.1
Resource use, fossils (MJ)	1.90E+01	2.19E+01	13	2.06E+01	2.27E+01	9.3
Resource use, mineral and metals (kg Sb eq.)	3.03E−05	3.03E−05	0	3.03E−05	3.03E−05	0
Water use (m3 world eq.)	2.43E−01	2.59E−01	6.2	3.09E−01	3.12E−01	1.0

CFC‐11, trichlorofluoromethane; CTUe, comparative toxic unit for ecosystems; CTUh, comparative toxic unit for humans; NMVOC, non‐methane volatile organic compounds.

Additionally, the difference between baseline and scenario are included. Results are in characterised impact scores via EF 3.1.

The environmental advantage of Bio‐ABS was robust to modelling assumptions. Even when attributing environmental burdens to waste cooking oil feedstock (rather than considering it burden free), Bio‐ABS maintained a reduced carbon footprint compared to fossil‐based ABS. Specifically, in this conservative scenario, the carbon footprint remained lower at 1.57 vs 1.63 kg CO₂ eq. in the USA, and 1.67 vs 1.74 kg CO₂ eq. in the UK, highlighting the resilience of material substitution benefits (see Appendix S4 for detailed information on sensitivity analyses).

Discussion

This LCA demonstrates that partial substitution of fossil‐based ABS with bio‐attributed ABS is associated with a consistent reduction in the carbon footprint of a single‐use cystoscope, across both UK and USA use scenarios. As plastics are a growing and under‐recognised cause of death and are responsible for health‐related economic losses exceeding $1.5 trillion (US dollars) annually [24], the present results reflect an important incremental step, confirming that material innovation can meaningfully contribute to the decarbonisation of urological practice.

These findings extend our previous work comparing reusable and single‐use cystoscopes, in which raw material production, sterilisation, and packaging were identified as the dominant environmental hotspots [5]. In the present study, plastics remained the principal contributors to climate change and fossil resource use, while sterilisation (driven by electricity demand in a fossil‐dominated grid) represented a major burden within the manufacturing stage. The introduction of Bio‐ABS directly addresses one of these upstream hotspots and results in a measurable climate benefit, even when conservative assumptions are applied to the bio‐circular feedstock. Notably, replacing Bio‐ABS entirely with fossil‐based ABS led to a clear deterioration in environmental performance, reinforcing the relevance of bio‐attributed polymers as a mitigation strategy.

Despite these improvements, packaging emerged as a substantial contributor across multiple impact categories, including land use, water use, and eutrophication. This highlights that material substitution alone is insufficient to achieve substantial decarbonisation of single‐use endoscopy and that packaging redesign and optimisation represent a major, under‐explored opportunity for impact reduction [25, 26]. Similarly, contribution analyses showed that transport and EoL management exert category‐specific influences, underscoring the importance of regional infrastructure and logistics in shaping environmental outcomes [27].

Sensitivity analyses provided important insights into the robustness of the results. While the carbon footprint reduction associated with Bio‐ABS persisted across all tested scenarios, the magnitude of benefit was moderately sensitive to assumptions regarding the treatment of bio‐circular feedstock, particularly when environmental burdens were attributed to waste‐derived inputs. By contrast, results were insensitive to moderate uncertainty in sterilisation utility estimates, supporting the reliability of the primary manufacturing data. Together, these analyses highlight both the strengths and boundaries of current modelling approaches and emphasise the need for transparent reporting of allocation choices in healthcare LCAs [28].

Importantly, environmental optimisation of cystoscopic practice should not be framed as a binary choice between reusable and single‐use technologies. While material innovation and improved EoL pathways can reduce the footprint of disposable devices, substantial gains may also be achievable through optimisation of reusable device reprocessing, including automation, reduced water and energy demand, and more efficient use of consumables. Recent studies have demonstrated the environmental benefits of such approaches for both cystoscopes and ureteroscopes [29, 30]. Sustainability efforts should therefore be context‐specific and multifactorial, integrating device design, material selection, reprocessing practices, logistics, and local infrastructure.

This study has several limitations. As with all attributional LCAs, results are dependent on system boundaries, allocation rules, LCIA methods, and data availability. Capital goods were excluded, and several processes relied on secondary datasets or manufacturer‐provided estimates, which may influence absolute values. Geographical representativeness was limited by data availability. However, these constraints are unlikely to affect the direction or relative magnitude of the observed effects, especially with respect to material substitution. Second, allocation choices may influence the magnitude of results. While a cut‐off approach was applied to bio‐circular feedstocks, upstream burdens associated with waste generation were not included in the base case, which may lead to a conservative (lower‐bound) estimate of impacts. Although supplier‐specific feedstock shares were unavailable, sensitivity analysis using used cooking oil as a proxy provides a conservative estimate of the potential impact of assigning burdens to bio‐circular inputs. Future analyses would benefit from greater transparency in bio‐feedstock sourcing. In addition, energy recovery from incineration was modelled using system expansion, whereas a strict cut‐off approach would exclude such credits from the product system. These methodological choices may contribute to an underestimation of absolute environmental impacts, although sensitivity analyses suggest that the relative differences between scenarios remain robust. Moreover, electronic components were modelled using generic PCB datasets from background databases, which may not fully reflect the specific architecture and manufacturing complexity of miniaturised endoscopic imaging systems. Furthermore, clinical effectiveness, cost, and behavioural factors influencing real‐world waste management were beyond the scope of this analysis. Finally, the modelling of bio‐attributed ABS relies on supplier‐provided certification under the mass‐balance framework. While Ambu A/S is not itself ISCC registered, the polymer supplier holds valid ISCC PLUS certification, ensuring third‐party verification of feedstock traceability and attribution. Due to commercial confidentiality, supplier identities and certification documents cannot be publicly disclosed. This limitation reflects a broader challenge in conducting transparent LCAs of medical devices that depend on complex and proprietary supply chains.

Conclusion

In conclusion, this study provides evidence that bio‐attributed plastics can contribute to the environmental improvement of single‐use urological devices, while also demonstrating that meaningful progress towards sustainable endoscopy will require a multifaceted approach, encompassing material sourcing, packaging design, energy use, and post‐use waste management. Importantly, clinicians have a critical role in this transition: optimising disposal pathways, supporting recycling initiatives, and engaging with manufacturers on design choices will be essential to translate material innovation into real‐world environmental gains.

Author Contributions

FORCE Technology independently conducted the life cycle modelling, inventory assessment, and environmental calculations. The authors were responsible for study conceptualisation, interpretation of results, manuscript preparation, and critical revision of the work.

Disclosure of Interests

All authors have approved the final version and declare no competing interests beyond the funding disclosed in the manuscript. The manufacturer had no role in the study design, data collection, data analysis, interpretation, or manuscript preparation.

Supporting information

Appendix S1. The data sources, data quality considerations, and assumptions used to construct the LCI for the assessed single‐use flexible cystoscope.

Appendix S2. The life cycle stages, modelling choices, and key assumptions underpinning the LCA.

Appendix S3. Contribution analysis to identify the materials and life‐cycle processes driving the environmental impacts of the cystoscope across impact categories.

Appendix S4. Sensitivity analyses of different scenarios.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.