Introduction
Methods
Requirements analysis
ID | System goals | Requirements | |||
---|---|---|---|---|---|
SG1 | Vendor-independent exchange of contextual information | R01 | The interface shall be based on a standardized syntax | Interoperability | [13] |
R02 | The interface shall be based on a standardized semantic | Interoperability | [13] | ||
SG2 | Device-independent exchange of contextual information | R03 | Contextual information must be continuously accessible by the CAS | Interaction | [23] |
R04 | Resource-constrained devices must be able to act context-sensitively | Interaction | [23] | ||
SG3 | Configurable exchange of contextual information | R05 | CAS must be able to specifically query contextual information entities | Interaction | [21] |
R06 | CAS must be able to subscribe to specifically contextual information entities | Interaction | [23] | ||
R07 | Contextual information can have a varying level of granularity | Interaction | [26] | ||
SG4 | Controllable exchange of contextual information | R08 | Contextual information must be provided simultaneously to multiple CAS | Risk management | [7] |
R09 | The interface is not responsible for triggered context-aware functionality | Risk management | [21] | ||
R10 | Changing contextual information shall be provided atomically | Risk management | [21] | ||
R11 | The interface shall be fault-tolerant regarding missing contextual information | Risk management | [1] |
Selection of a base architecture
Specification and implementation of the middleware
Evaluation strategy
Results
Specification of the interface
Data model
Element | Intended use | Example |
---|---|---|
Channel descriptor | ||
> Code | Specifies the meaning of the channel semantically unambiguously using the SDC nomenclature [32] | Functional context [30] (local extension) |
> Handle | Uniquely identifies the MIDB element | CHAN_FC |
String metric descriptor | ||
> Code | Specifies the meaning of the contextual information entity semantically unambiguously using the SDC nomenclature [32] | Surgical phase (local extension) |
> Derivation method | Specifies whether the contextual information entity is acquired automatically or via manual input | Automatically |
> Handle | Uniquely identifies the MIDB element | FC_SP |
> Max delay time | Specifies the average duration from the determination of the contextual information entity to its provision in the MDIB | 500 ms |
> Metric availability | Specifies whether the contextual information entity is continuously or intermittently available | Continuously |
> Relation | Specifies a dependency to another String Metric Descriptor | |
>> Code | Specifies the meaning of the relation semantically unambiguously using the SDC nomenclature [32] | Contains (local extension) |
>> Entries | Referencing the associated String Metric Descriptor Handles | FC_SS (surgical step) |
>> Kind | Specifies the relationship to the associated metrics | Effect on containment tree entries |
> Unit | Assigns a measurement unit from the SDC nomenclature [32] to the metric | Dimensionless |
Channel state | ||
> Activation state | Expresses whether the channel provides valid metrics, or if all metrics are currently invalid | On |
> Operating hours | Represents how long the channel provides valid metrics | 2 |
String metric state | ||
> Metric quality | Express the representativeness of the current value of the contextual information entity | |
>> Measurement validity | Indicates whether the value of the metric is valid or should currently not be used (e.g., if the SRS could not estimate a value) | Valid |
>> Quality | Percentage of how confident the estimation of the contextual information value is | 0.97 |
> Start time | Timestamp since when the current value of the contextual information entity has been provided | 1640863190706 (December 30, 2021, 11:19:50) |
> Stop time | Timestamp until when the value of the contextual information entity was valid or had been replaced by a new value | |
> String metric value | Represents the current value of the specific contextual information entity | Implantation of prosthetic stem |
Systematic name | Description | Partition::Code |
---|---|---|
Situation Recognition System|Functional Context | Channel of an SRS containing metrics that offer information about the functional context according to [30] | 1::61443 |
Situation recognition system|Procedure-related context | Channel of an SRS containing metrics that offer information about the function context according to [30] | 1::61444 |
Functional context|Surgical phase | Current surgical phase of the intervention | 2::61440 |
Functional context|Surgical step | Current surgical step specifying a Surgical Phase | 2::61441 |
Functional context|Surgical activity | Current surgical activity specifying a Surgical Step | 2::61442 |
Functional context|Relation|Contains | A granular lower-level entity of the functional context contains a granular higher entity | 2::61443 |
Procedure-related context|Remaining surgery duration | Estimated remaining duration of the intervention | 2::61444 |
Procedure-related context|Delay | Calculated delay of the intervention depending on the RSD | 2::61445 |
Service model
Get
service as mandatory, whose operations can be used to request specific contextual information entities from the SRS. The Context
service enables the orchestration of the SRS and CAS based on the System Context in the respective MDIBs. The Archive
service shall be provided by an SRS to access previous MDIB states. This allows reconstructing the course of an intervention, e.g., for automatic documentation. For notifying CAS about context changes, the SRS offers the Description Event
and the State Event
service. During an intervention, the descriptive part of the MDIB shall not be modified. The temporary unavailability of contextual information entities can be represented via the Measurement Validity of the Metric Quality without changing the MDIB structure of the SRS. If all metrics in a Channel are invalid at some time, the Activation State of the Channel should be on standby. If CAS subscribed for changes of these MDIB entities, they will be notified automatically about this availability change. The specified services of the SRS are illustrated in Fig. 2.Implementation of the middleware
Generic implementation
Integration in the OR-Pad use case
IORC_FC_SP
and IORC_PRC_D
metric. If new information is retrieved via the notification pipe, the OR-Pad displays these in the user interface. Depending on the surgical phase, the OR-Pad searches for the assigned information and displays this beneath the displayed phase to make the information accessible with one click.Evaluation
Archive
service is currently not provided by the sdcLib.