Example Governed Decision Record, Engineering
Companion artefact, regulated product design review
This example shows how an OMEGA record acts as legally defensible, contemporaneous evidence for an engineering design review decision in a regulated product. The setting is a surgical robotics end effector design held to ISO 13485 design controls and MHRA Class IIb medical device expectations.
Manufacturers of regulated products carry liability and accountability that outlast the design cycle. Notified body audits, MHRA enquiries, and product liability proceedings can ask a specific question about a specific decision years after it was taken. An OMEGA record preserves the reasoning, the evidence, the authority chain, and the rejected paths as they were on the day, sealed at decision time, so the firm can answer the question rather than reconstruct it.
This is a stylised example. It is structurally accurate but not authoritative engineering or regulatory guidance, and does not represent any specific device, manufacturer, or organisation.
GOVERNED DECISION RECORD
Record ID: omega-record/2026-05-09/surgical-gripper-v0.7.3
Schema Version: omega/1.0
Domain: engineering.medical-device.design-review
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CONTEXT
A surgical robotics team has produced a candidate
end-effector design (Iteration v0.7.3) for use in
laparoscopic soft tissue manipulation. The design
must be reviewed before any prototype construction,
in line with the team's design review protocol under
ISO 13485 (medical device quality management) and
the device's intended classification as Class IIb
under MHRA medical device regulations.
The design follows two earlier iterations that did
not progress: v0.7.1 was rejected at physics
validation due to contact pressure exceeding tissue
tolerance thresholds; v0.7.2 was returned for
revision after workflow integration analysis showed
incompatibility with existing laparoscopic port
geometries.
The current design has passed physics validation
and workflow integration analysis. The design
review board must decide whether to advance v0.7.3
to physical prototype, request further simulation,
or reject and return to design phase.
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DECISION
Advance Iteration v0.7.3 to physical prototype with
two design constraints applied: elastomer durometer
specification raised from Shore 30A to Shore 40A,
and contact surface curvature radius increased from
4mm to 6mm. Prototype to be validated against
bench-test protocol BT-2026-031 before any cadaver
or pre-clinical evaluation.
Decision time: 14:42
Decision date: 9 May 2026
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REASONING
The decision was made by applying the team's design
review framework to the physics validation report
and structured case analysis from the substrate
pipeline.
Three factors supported progression with constraints:
1. Finite element analysis indicates the design
operates within structural and tissue-tolerance
margins under normal use (maximum contact pressure
142 kPa against tolerance threshold of 180 kPa)
2. Design failure mode and effects analysis (DFMEA)
returned zero critical failures and two flagged
concerns; comparison against the team's design
verification matrix ranked the design fourth of
seventeen candidates evaluated for similar use
cases
3. Workflow integration analysis confirmed
compatibility with the laparoscopic port
geometries that previous iterations failed
against
Two constraints were applied to address the soft
warnings rather than reject the design outright.
Raising elastomer durometer reduces deflection
under maximum grip load (warning: stress
distribution acceptable but margin narrower than
preferred). Increasing contact surface curvature
radius reduces pressure variability across grip
contact area (warning: pressure peaks at edge
contact under angular grip).
Returning to design phase was considered but
rejected: the warnings flagged by physics validation
and structured analysis are addressable through
parameter adjustment rather than fundamental
redesign. Further simulation without prototype was
considered but rejected: physical bench testing
will surface failure modes that simulation cannot
fully predict, and the design has reached the
maturity where physical validation is the next
appropriate step.
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EVIDENCE AND ASSUMPTIONS
Evidence used:
- Finite element analysis report for v0.7.3
(maximum contact pressure 142 kPa, deflection
under load 0.34mm, shear failure predicted at
4.2x normal operating load)
- Design failure mode and effects analysis
(DFMEA) covering surgical robotics use cases:
zero critical failures, two flagged concerns,
ranked fourth of seventeen candidates in the
team's design verification matrix
- Tissue tolerance baseline (record/engineering/
2026-03-15) derived from porcine soft tissue
trial data
- Prior design iteration outcomes (v0.7.1
rejected, v0.7.2 returned for revision)
- Workflow integration assessment against
standard laparoscopic port geometries
(5mm, 10mm, 12mm)
Assumptions explicitly recorded:
- Tissue tolerance baseline: porcine data is
the best available proxy for human soft tissue
response, but human variability in tissue
properties may exceed the 12% margin used in
threshold setting
- Physics validation accuracy: simulation
boundary conditions assume idealised contact
geometry; real surgical conditions involve
irregular tissue surfaces that may produce
higher localised pressures than modelled
- Workflow integration: validated against three
standard port sizes; performance with smaller
port geometries (3mm pediatric) not assessed
and would require separate validation
- Bench test protocol BT-2026-031: assumed
sufficient for prototype validation, subject
to quality team confirmation
═══════════════════════════════════════════════════
AUTHORITY
Decision authorised by: Design Review Board
- Lead Engineer: [name], Principal Engineer
- Consultant Surgical Advisor: [name],
Consultant Laparoscopic Surgeon
- Regulatory Affairs Lead: [name], Senior
Regulatory Affairs Manager
Authority basis: Design review under ISO 13485
clause 7.3.4, with regulatory affairs concurrence
required for design progression decisions on
Class IIb medical devices per the team's design
control procedure DCP-2026-04.
Quorum: All three signatories present at decision
time. Substrate runtime verified all signatories
present.
═══════════════════════════════════════════════════
CONSTRAINTS CHECKED
The following were evaluated before the decision
was committed:
✓ Finite element analysis passed (FEA report
attached)
✓ Workflow integration assessment passed
(compatible with standard laparoscopic ports)
✓ Tissue tolerance margin acceptable under
current baseline assumptions
✓ Design control documentation complete (ISO
13485 clause 7.3.4 requirements met)
✓ Risk management file updated (ISO 14971)
✓ Software safety classification confirmed
(IEC 62304 Class B for control firmware)
✓ Bench test protocol identified and resourced
⚠ Pediatric port compatibility (3mm) flagged
for future validation but does not block
current adult-indication progression
⚠ Tissue baseline derived from porcine data
flagged as known limitation, scheduled for
review when human tissue data becomes
available from partner institution
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DISPUTES
One disagreement was recorded during this decision.
The Consultant Surgical Advisor queried whether the
applied constraint of Shore 40A durometer would
reduce tissue handling sensitivity to a degree that
affects intraoperative judgment. The advisor's
clinical experience suggests softer elastomer
provides better tactile feedback through the grip
mechanism, and increased durometer may compromise
the surgeon's ability to detect tissue
characteristics during manipulation.
The query was considered: physics validation
indicates Shore 30A would operate at narrower
safety margin under maximum grip load; Shore 40A
maintains the safety margin while reducing tactile
sensitivity by an estimated 8-12% based on
manufacturer specifications.
Resolution: progression with Shore 40A constraint
proceeded. The advisor's concern was recorded with
the prototype evaluation plan: bench testing will
include tactile feedback assessment alongside
mechanical performance, and if clinical sensitivity
requirements emerge as critical, alternative
elastomer compounds offering better feedback at
equivalent durometer will be evaluated in v0.7.4.
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CONSENT
Consent and information sharing:
- Decision is internal design review; no
patient or clinical stakeholder consent
required at this stage
- Design review documentation shared with
notified body in line with technical file
requirements for Class IIb device
- FEA report and DFMEA analysis included in
design history file
Stakeholder voice:
- Surgical advisor consulted with clinical
perspective recorded
- Quality team review pending for bench test
protocol confirmation
- End-user surgical team will be consulted
before cadaver evaluation phase
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HARM TRACE
Anticipated harm chains evaluated:
If progression with constraints (chosen path):
- Risk: prototype testing may reveal failure
modes simulation did not predict
- Mitigation: bench test protocol BT-2026-031
designed to surface mechanical and tactile
failure modes before any tissue contact
- Mitigation: cadaver evaluation gated on
successful bench test completion
- Residual risk: low to moderate
If progression without constraints (rejected path):
- Risk: tissue tolerance margin narrower than
preferred under maximum grip load conditions
- Risk: pressure variability across contact
area higher than acceptable for delicate
tissue manipulation
- Residual risk if pursued: moderate
If rejection and return to design phase (rejected
path):
- Risk: design progress delayed by approximately
six weeks, affecting development timeline
- Risk: warnings flagged are addressable through
parameter adjustment rather than fundamental
redesign, making rejection disproportionate
- Residual risk if pursued: development
timeline slippage with no corresponding
safety improvement
If further simulation without prototype (rejected
path):
- Risk: simulation boundary conditions cannot
fully model real surgical contact geometry
- Risk: continued simulation without physical
validation produces diminishing confidence
returns
- Residual risk if pursued: moderate (delay
without proportionate evidence gain)
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OUTCOME
Recorded at 16:30 (1 hour 48 minutes post-decision):
Design constraint specification updated and
released to manufacturing partner. Prototype
fabrication scheduled for week commencing 12 May
2026, with bench test protocol BT-2026-031
preparation underway in parallel.
Surgical advisor's tactile sensitivity concern
formally added to bench test scope. Alternative
elastomer compound research initiated for v0.7.4
contingency.
Pediatric port compatibility added to backlog
for future iteration; not blocking current
progression.
The decision is closed with outcome COMMITTED.
Bench test results scheduled to feed back into
design review board before any cadaver evaluation
authorisation. No retrospective review flagged.
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PROVENANCE
Content hash:
sha256:3e7a5c8d1f9b4a2c6e1f8b3d5a7c9e2f4b8d1a3c5e7f9b2d4a6c8e1f3b5d7a9c2e4f6b8d1a3c5e7f9b
Previous record hash:
sha256:8b2d5e1f7a4c9b3d6e2f8a1c5b9d3e7f4a2c8b1d6e9f3a5c7b2d4e8f1a6c9b3d5e7f2a4c8b1d6e9f3a
(preceding record in surgical robotics design
chain, v0.7.2 design review return)
Schema validation: passed (omega-contracts v0.2.2)
Cryptographic seal: valid
Composition: substrate_native_records →
omega_records (canonical envelope)
The substrate paper describing the underlying architecture is available at /substrate/.