Research Fellow Washington University School of Medicine St. Louis, Missouri, United States
Introduction: Systemic hypotension after spinal cord injury (SCI) is well-established to contribute to cord ischemia. On the other hand, aggressive mean arterial pressure (MAP) control can precipitate secondary injury to the spinal cord. In lieu of the problems of using MAP to guide the acute perfusion needs of the spinal cord, additional modalities for monitoring the spinal cord perfusion pressure (SCPP) need to be evaluated to guide the hemodynamic management of SCI.
Methods: MEDLINE, EMBASE, Web of Science, and Clinical Trials.gov were queried for studies published between 2010-2020 that evaluated intrathecal devices to monitor the SCPP. Data extracted included study design, patient population, characteristics of the intrathecal device, and health effects. ROB2 and the ROBINS-I rating scales were used to assess the risk of bias.
Results: 23 of the 3,919 unique citations met the eligibility criteria. 8 studies (7 observational and 1 randomized controlled trial) assessed the effects of lumbar drain catheter, and 15 studies assessed the effect of a Codman pressure probe inserted at the site of injury. These studies found that episodes of SCPP < 50 mm Hg were associated with failure to achieve neurological improvement by at least one ASIA grade after 6 months at follow-up (OR 0.9, p 0.031). Clinical adherence to the target perfusion range of 65 mm Hg was positively related to neurological improvement by at least one ASIA grade. Codman pressure probe studies revealed that the SCPP values at 90-100 mmHg are associated with the best ASIA recovery at 9-12 months (OR 1.039, p 0.002). These studies reported a 7% incidence of persistent CSF leakage requiring revision after device insertion. This risk of bias among all included studies ranged from moderate-to-severe across all domains.
Conclusion : The included studies demonstrated a positive correlation between SCPP measurement and neurological improvement post-injury. Due to the risk of bias, it is difficult to discern the true health effects of these approaches. Lumbar drains can be easily inserted but are not near to the site of injury. Codman probe can monitor pressure close to the injury site but requires duroplasty. Further investigation is needed to determine the true effects of these interventions.
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