WEB™ SLS: Spherical Single-Layer Flow Disruptor for Symmetrical Bifurcation Aneurysms

The WEB™ SLS (Single Layer Spherical) is a variant of the WEB intrasaccular flow disruptor designed for aneurysms where the sac has a roughly spherical geometry — meaning width and height are approximately equal. The standard WEB SL is a bilobed cylindrical device sized by both width and height; for aneurysms where W ≈ H, the SLS offers a spherical alternative that simplifies sizing to a single measurement (the sac diameter), and whose spherical shape may provide better wall apposition in uniformly round sacs.

Both WEB SL and WEB SLS deploy intrasaccularly via VIA microcatheters, require no parent-artery stent, and eliminate the DAPT requirement. They differ only in shape and sizing algorithm: SL for aneurysms with a clear width-height ratio requiring two measurements; SLS for roughly spherical aneurysms where a single diameter suffices. In practice, many neurointerventionalists stock both variants and select based on individual aneurysm morphology measured from 3D DSA.

The WEB SLS is available in nominal diameters from 4 mm to 11 mm: WEB SLS 4, 5, 6, 7, 8, 9, 10, and 11. Each size is delivered via the corresponding VIA microcatheter matched to that diameter range. The single-measurement sizing reduces pre-procedure planning time and simplifies device selection in emergency procedures where extended 3D DSA analysis may not be available.

The spherical mesh geometry of the SLS creates radially uniform contact with the aneurysm wall in spherical sacs, providing consistent coverage across the entire inner surface. In sacs with a clear width-height asymmetry, the SL’s bilobed shape is better matched to the aneurysm geometry.

The WEB SLS is primarily indicated for spherical or near-spherical wide-neck bifurcation aneurysms where the dome-to-neck ratio is 1.0–1.2 and the width equals the height. Aneurysms fitting this profile are found at all the standard WEB locations (MCA, AComA, ACA, basilar apex, ICA terminus) and represent a substantial proportion of the wide-neck bifurcation aneurysm population.

In emergency settings — ruptured aneurysms requiring immediate treatment — the SLS’s single-measurement sizing accelerates device selection when prolonged pre-procedure planning is not possible. The SLS can be selected from a quick measurement of the maximum sac diameter on the conventional DSA run without requiring a separate 3D DSA acquisition if time does not permit.

Size the WEB SLS 0.5–1.0 mm above the measured maximum sac diameter to ensure adequate wall apposition. An undersized SLS will not achieve neck coverage and will be mobile within the sac, which is the most common technical failure mode. If the aneurysm is borderline between two SLS sizes, select the larger size.

Use the V-Grip handle for precise SLS positioning within the sac before detachment. The SLS can be fully resheathed and repositioned multiple times before electrolytic detachment — use this capability to optimise neck coverage before committing to detachment.

Modern Medical Solutions is the authorised MicroVention Terumo distributor for Tajikistan and Afghanistan. WEB SLS is available in all sizes for neurointerventional programmes in Tajikistan and Afghanistan.

Contact Modern Medical Solutions to discuss WEB SLS alongside WEB SL, VIA microcatheters, V-Grip, and the Detachment Controller as a complete WEB intrasaccular device system.