Evidence map›Paper›PMID 41417231›Full record

ArticleEuropean spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society2026

Old technique, new applications: can the H-reflex be a possible real-time indicator in endoscopic surgery for decompression of acute disc herniation at the S1 root?

Marta Rodrigues Carvalho, Vitor Caldas Marques, Baldomero Pinto Soares, Gabriel Pokorny, Thiego Pedro, Mario Bringel, Rodrigo Grion

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Article in European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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5 · Who and what money

Authors and funding

7 authors.

Marta Rodrigues CarvalhoDepartment of Neurology and Clinical Neurophysiology, Instituto Hospital de Base do Distrito Federal, Brasília, Brazil.
Vitor Caldas MarquesInstituto Ranvier, Brasília, Brazil.
Baldomero Pinto SoaresHospital Santa Luzia, Brasília, Brazil.
Gabriel PokornyIndependent Author, São Paulo, Brazil. ghpokorny@gmail.com.
Thiego PedroHospital Sírio-Libanês, Brasília, Brazil.
Mario BringelUniversidade Católica de Brasília, Brasília, Brazil.
Rodrigo Grion- Centro de Ortopedia e Traumatologia Especializado, Brasília, Brazil.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe Hoffmann (H-) reflex is a monosynaptic electrophysiological response that reflects S1-root integrity. Although widely used in experimental and in clinical outpatient neurophysiological testing, its intra-operative application during endoscopic lumbar surgery is rarely reported. We present the first real-time documentation of H-reflex normalization immediately after endoscopic decompression of an acute L5-S1 disc herniation. CASE DESCRIPTION: A 49-year-old woman presented with acute right-sided S1 radiculopathy (ankle dorsiflexion/plantar-flexion MRC grade III; hallux extension grade I). MRI showed a large, right sub-articular L5-S1 disc extrusion compressing the S1 nerve root. Unilateral biportal endoscopic discectomy was performed under general anesthesia with multimodal intra-operative neuromonitoring (MEPs, free-run EMG, and continuous tibial-nerve H-reflex). Baseline recordings revealed marked side-to-side asymmetry: right-leg MEP amplitudes were depressed, and the right H-reflex was low and unstable. During foraminoplasty and fragment removal, a sudden, sustained 100% surge in right H-reflex amplitude occurred, coincidence with root decompression, while MEPs remained unchanged. Free-run EMG discharges abated after the H-reflex improved. Post-operative recovery was uneventful. At 2 months the patient demonstrated near-complete motor recovery (MRC IV-V) and full pain relief.

conclusionContinuous H-reflex monitoring provided an immediate, sensitive marker of S1-root decompression when conventional MEPs failed to reflect functional recovery. This single-case experience supports the feasibility and potential prognostic value of adding H-reflex surveillance to the neuromonitoring toolkit for endoscopic lumbar surgery. Prospective studies in larger cohorts are warranted to validate threshold criteria, refine stimulation parameters, and determine cost-effectiveness.

Indexed as

Decompression, SurgicalEndoscopyH-ReflexIntervertebral Disc DisplacementRadiculopathySpinal Nerve RootsFemaleHumansLumbar VertebraeMiddle AgedSacrumDisc HerniationEndoscopicH-ReflexLumbar DecompressionNeuromonitoring

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.