AUTHOR=Kheram Najmeh , Pfender Nikolai , Boraschi Andrea , Farshad Mazda , Kurtcuoglu Vartan , Curt Armin , Schubert Martin , Zipser Carl M. 

TITLE=Cerebrospinal fluid pressure dynamics reveal signs of effective spinal canal narrowing in ambiguous spine conditions

JOURNAL=Frontiers in Neurology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.951018

DOI=10.3389/fneur.2022.951018

ISSN=1664-2295

ABSTRACT=Spinal canal narrowing with consecutive spinal cord compression is considered a key mechanism in degenerative cervical myelopathy (DCM). DCM is a common spine condition associated with progressive neurological disability and timely decompressive surgery is recommended. However, the clinical and radiological diagnostic workup is often ambiguous, challenging confident proactive treatment recommendations. Cerebrospinal fluid pressure dynamics (CSFP) are altered by spinal canal narrowing. Therefore, we aim to explore the potential value of bedside CSFP assessments for qualitative and quantitative assessment of spinal canal narrowing in DCM. In this prospective case series seven patients with DCM underwent bedside lumbar puncture with measurement of CSFP dynamics and routine CSF analysis (NCT02170155). Patients were enrolled when standard diagnostic algorithms did not permit a clear treatment decision. Measurements include baseline CSFP, cardiac-driven CSFP peak-to-trough amplitude (CSFPp), and Queckenstedt's test (firm pressure on jugular veins) in neutral and reclined head position. From Queckenstedt's test, proxies for craniospinal elastance (i.e., relative pulse pressure coefficient; RPPC-Q) were calculated analogously to infusion testing. CSFP metrics were deemed suspicious of canal narrowing when numbers were lower than the minimum value from a previously tested elderly spine-healthy cohort (N=14). Mean age was 56 ± 13 years (range 38-75; 2F), symptom severity was mostly mild to moderate (mean mJOA 13.5 ± 2.6, range 9-17). All patients showed some extent of cervical stenosis in the MRI of unclear significance (5/7 following decompressive cervical spine surgery with adjacent level or residual stenosis). Baseline CSFP was normal except for one patient (range 4.7- 17.4 mmHg). Normal values were found for CSFPp (0.4-1.3 mmHg) and Queckenstedt's test in normal head positioning (9.0-25.3 mmHg). During reclination, Queckenstedt's test significantly decreased in one, and CSFPp in another case (>50% compared to normal position). RPPC-Q (0.07-0.19) aligned with lower values from spine-healthy (0.10-0.44). Routine CSF examinations showed mild total protein elevation (mean 522 ± 108 mg/ml) without further evidence for disturbed blood brain barrier. Intrathecal CSFP measurements allow discerning disturbed from normal CSFP dynamics in this population. Prospective longitudinal studies should further evaluate the diagnostic utility of CSFP assessments in DCM.