Three CT Signs of Nerve-root Suffering in Low-back Sciatica: a Study of Their Frequency in Patients Referred for CT-guided Nerve-root Infiltration.

Retrospective, observational, single-centre study conducted at Nice University Hospital (Pasteur 2), Department of Diagnostic and Interventional Radiology. Objective: to assess the prevalence of three CT signs sought next to the clinically suspected nerve root in patients with low-back sciatica referred for CT-guided foraminal/peri-radicular infiltration: (1) nerve-root size asymmetry/hypertrophy, (2) peri-radicular infiltration, and (3) spontaneous root hyperdensity. Hypothesis: these signs are associated with the suffering nerve root responsible for the clinical presentation. Pre-infiltration planning CT scans (period 30 Jan 2024 - 11 Jul 2024) are reviewed by the operating radiologists (4th-, 5th- and 6th-year residents). Target enrollment: 400 patients. Data analysed to date: 104 patients / 105 infiltrations. Preliminary prevalence: root asymmetry/hypertrophy 45.5%; peri-radicular infiltration 50.5%; spontaneous hyperdensity 23.8%; at least 2 of 3 signs 38.6%; all 3 signs 16.8%. Mean age 65 years (range 25-93); approximately 62 women / 42 men; predominant levels L4-L5 and L5-S1.

Inclusion Criteria: * Adult (\>= 18 years) * Low-back sciatica / radicular pain with a systematized distribution * Referred for CT-guided foraminal or peri-radicular infiltration at Pasteur 2 Hospital (Nice) between 30 Jan 2024 and 11 Jul 2024. * Available and interpretable pre-infiltration planning CT Exclusion Criteria: * Planning CT missing or not interpretable * Missing data on the three studied signs * Radicular pain of tumoral, infectious or recent traumatic origin * Spinal history precluding analysis of the studied root