Predictive Value of Midsagittal Tissue Bridges on Functional Recovery After Spinal Cord Injury

Abstract

Background The majority of patients with spinal cord injury (SCI) have anatomically incomplete lesions and present with preserved tissue bridges, yet their outcomes vary. Objective To assess the predictive value of the anatomical location (ventral/dorsal) and width of preserved midsagittal tissue bridges for American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade conversion and SCI patient stratification into recovery-specific subgroups. Methods This retrospective longitudinal study includes 70 patients (56 men, age: 52.36 ± 18.58 years) with subacute (ie, 1 month) SCI (45 tetraplegics, 25 paraplegics), 1-month neuroimaging data, and 1-month and 12-month clinical data. One-month midsagittal T2-weighted scans were used to determine the location and width of tissue bridges. Their associations with functional outcomes were assessed using partial correlation and unbiased recursive partitioning conditional inference tree (URP-CTREE). Results Fifty-seven (81.4%) of 70 patients had tissue bridges (2.53 ± 2.04 mm) at 1-month post-SCI. Larger ventral ( P = .001, r = 0.511) and dorsal ( P < .001, r = 0.546) tissue bridges were associated with higher AIS conversion rates 12 months post-SCI (n = 39). URP-CTREE analysis identified 1-month ventral tissue bridges as predictors of 12-month total motor scores (0.4 mm cutoff, P = .008), recovery of upper extremity motor scores at 12 months (1.82 mm cutoff, P = .002), 12-month pin-prick scores (1.4 mm cutoff, P = .018), and dorsal tissue bridges at 1 month as predictors of 12-month Spinal Cord Independence Measure scores (0.5 mm cutoff, P = .003). Conclusions Midsagittal tissue bridges add predictive value to baseline clinical measures for post-SCI recovery. Based on tissue bridges’ width, patients can be classified into subgroups of clinical recovery profiles. Midsagittal tissue bridges provide means to optimize patient stratification in clinical trials.

Acute Implantation of a Bioresorbable Polymer Scaffold in Patients With Complete Thoracic Spinal Cord Injury: 24-Month Follow-up From the INSPIRE Study

“…However, it should be noted that greater cord tissue width at 1 month postinjury has been shown to be predictive of better outcomes at 1 year. 22 , 23 Patients with no or smaller cysts will have wider tissue bridges; therefore, it is logical to assume that those with cysts will have less endogenous sprouting and a lower likelihood of AIS conversion.…”

Finger somatotopy is preserved after tetraplegia but deteriorates over time

“…Spared spinal cord tissue bridges can be found in most patients with a clinically incomplete injury, their width being predictive of electrophysiological information flow, recovery of sensorimotor function, and neuropathic pain ( Huber et al, 2017 ; Pfyffer et al, 2021 ; Pfyffer et al, 2019 ; Vallotton et al, 2019 ). However, in this study, spared midsagittal spinal tissue bridges at the lesion level and sensorimotor hand function did not seem necessary to maintain and activate a somatotopic hand representation in S1.…”

Improving Diagnostic Workup Following Traumatic Spinal Cord Injury: Advances in Biomarkers

“…The extent of preserved ventral and dorsal tissue paralleled patients’ recovery and electrophysiological recordings in several studies and was significantly related to patients’ walking ability [ 37 – 39 ]. Moreover, the width assessed at 1 month after injury was significantly associated with long-term neurological and neurophysiological outcome and could provide a more reliable prognostic measure [ 37 , 38 , 40 ••, 41 ]. In particular, the distinction between tract-specific impairment could serve as motor- and sensory-specific predictors separately, as ventral tissue bridges were significantly related to motor function and dorsal tissue bridges to sensory function [ 40 ••].…”