Spinal Access Retractor With Nerve-Monitored Sequential Dilation
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Solution Overview
Problem
Traditional open surgical techniques require large incisions and significant tissue displacement, leading to increased pain, morbidity, and healthcare costs, while minimally invasive approaches like the lateral transpsoas approach have shown promise but can be improved for faster operative times and broader applications.
Innovation Solution
A surgical access system with a dilation assembly and retraction assembly is used to create a lateral access corridor to the spine, featuring a retractor assembly with adjustable blades and nerve monitoring capabilities to minimize tissue disruption and avoid nerves, allowing for customizable access corridors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional open surgical techniques are used, then access to the surgical target site is achieved, but large incisions and significant tissue displacement are required, leading to increased pain, morbidity, and healthcare costs
Solution Approach 1:
The surgical access system divides the access corridor creation into sequential steps using multiple dilators of increasing diameter (e.g., 12mm, 14mm, 16mm, 18mm dilators). Each dilator creates a progressively larger pathway, allowing gradual tissue separation rather than single-step large-scale displacement, thereby reducing trauma and morbidity while achieving the same surgical access.
Solution Approach 2:
The system employs nested dilators where smaller dilators are inserted first, followed by progressively larger dilators that fit over the previous ones. The retractor assembly is then inserted over the final dilator. This nested arrangement allows systematic expansion of the access corridor with minimal incremental tissue disruption at each stage.
2Object-affected harmful factors
If minimally invasive lateral transpsoas approach is used, then patient morbidity and hospitalization length are reduced, but operative time and surgical complexity can be improved further
Solution Approach 1:
The system performs preliminary alignment and pathway creation using a guidewire and sequential dilators before inserting the final retractor assembly. Nerve monitoring is conducted during dilator insertion to pre-identify safe pathways. This preliminary preparation ensures that the final retractor insertion is quick and straightforward, reducing overall operative time while maintaining minimal invasiveness.
Solution Approach 2:
The system incorporates real-time nerve monitoring feedback during the dilation process. Electromyography (EMG) monitoring detects nerve proximity, providing immediate feedback to the surgeon to adjust the insertion path. This feedback mechanism prevents nerve injury and allows efficient navigation through the psoas muscle, reducing trial-and-error time and accelerating the procedural workflow.
3Device complexity
If a fixed retractor assembly is used, then the structure is simple, but it cannot adapt to different surgical targets and patient anatomies
Solution Approach 1:
The retractor assembly features dynamic adjustability with movable blades that can be independently positioned. The blades can be adjusted to different angles and depths to create access corridors of varying geometries. This dynamic configuration allows the same basic retractor structure to adapt to different surgical targets (e.g., different lumbar levels) and patient anatomies without requiring multiple fixed designs.
Solution Approach 2:
The system allows modification of key parameters including blade separation distance, blade angle, and insertion depth. These parameters can be adjusted intraoperatively based on surgical needs and patient-specific anatomy. The ability to change these parameters transforms a potentially complex multi-device system into a single versatile platform that can be configured for various surgical scenarios.
4Reliability
If nerve monitoring is performed during dilation and retraction, then nerve injury is avoided, but the procedural complexity and time required increase
Solution Approach 1:
The dilator and retractor assemblies are designed with integrated nerve monitoring capabilities built into their structures. Electrodes are incorporated onto the surfaces of the dilators and retractor blades, allowing the same surgical instruments to serve dual functions: mechanical tissue displacement and electrical nerve monitoring. This integration eliminates the need for separate monitoring devices, reducing overall system complexity while maintaining high reliability in nerve injury prevention.
Data Source
AI summary
A surgical access system comprising a tissue dilation assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures.