Predictors of Intraspinal Pressure and Optimal Cord Perfusion Pressure After Traumatic Spinal Cord Injury

Abstract

Background/ObjectivesWe recently developed techniques to monitor intraspinal pressure (ISP) and spinal cord perfusion pressure (SCPP) from the injury site to compute the optimum SCPP (SCPPopt) in patients with acute traumatic spinal cord injury (TSCI). We hypothesized that ISP and SCPPopt can be predicted using clinical factors instead of ISP monitoring.MethodsSixty-four TSCI patients, grades A–C (American spinal injuries association Impairment Scale, AIS), were analyzed. For 24 h after surgery, we monitored ISP and SCPP and computed SCPPopt (SCPP that optimizes pressure reactivity). We studied how well 28 factors correlate with mean ISP or SCPPopt including 7 patient-related, 3 injury-related, 6 management-related, and 12 preoperative MRI-related factors.ResultsAll patients underwent surgery to restore normal spinal alignment within 72 h of injury. Fifty-one percentage had U-shaped sPRx versus SCPP curves, thus allowing SCPPopt to be computed. Thirteen percentage, all AIS grade A or B, had no U-shaped sPRx versus SCPP curves. Thirty-six percentage (22/64) had U-shaped sPRx versus SCPP curves, but the SCPP did not reach the minimum of the curve, and thus, an exact SCPPopt could not be calculated. In total 5/28 factors were associated with lower ISP: older age, excess alcohol consumption, nonconus medullaris injury, expansion duroplasty, and less intraoperative bleeding. In a multivariate logistic regression model, these 5 factors predicted ISP as normal or high with 73% accuracy. Only 2/28 factors correlated with lower SCPPopt: higher mean ISP and conus medullaris injury. In an ordinal multivariate logistic regression model, these 2 factors predicted SCPPopt as low, medium–low, medium–high, or high with only 42% accuracy. No MRI factors correlated with ISP or SCPPopt.ConclusionsElevated ISP can be predicted by clinical factors. Modifiable factors that may lower ISP are: reducing surgical bleeding and performing expansion duroplasty. No factors accurately predict SCPPopt; thus, invasive monitoring remains the only way to estimate SCPPopt.Electronic supplementary materialThe online version of this article (10.1007/s12028-018-0616-7) contains supplementary material, which is available to authorized users.

Targeted Perfusion Therapy in Spinal Cord Trauma

“…Studies in pigs show that surface and intraparenchymal MD give comparable metabolite values in the pulsating heart [77] and liver [78]. For spinal cord, surface MD at the injury site differs markedly from corresponding measurements taken from the lumbar CSF [37]. The key findings of our study are that SCPP strongly correlates with injury site metabolic profile and that the extent of metabolic derangement and the probability of AIS grade conversion after TSCI correlate well with the degree of metabolic derangement at the injury site.…”

“…Increasing the dose of epinephrine increased MAP and consequently increased SCPP. Drainage of 10 mL CSF via a lumbar catheter did not significantly alter ISP in 58% of patients, significantly reduced ISP by < 5 mmHg in 33% of patients, and only significantly reduced ISP by 9 mmHg in 9% of patients [37]. Therefore, the only nonsurgical technique to reliably increase SCPP is to increase the MAP with vasopressors.…”

“…To find out whether lumbar CSFP is the same as ISP, we simultaneously monitored CSFP and ISP in 13 patients with severe TSCI and concluded that the 2 techniques yield markedly differ values for cord pressure (ISP ≠ CSFP), perfusion pressure (SCPP ISP ≠ SCPP CSF ), and pressure reactivity (sPRx ISP ≠ sPRx CSF ) [37]. CSFP was nonpulsatile 21% of the time or had simple waveforms, whereas ISP was always pulsatile with waveforms that had the characteristic P1-P2-P3 peaks.…”

Efficacy of Ultra-Early (< 12 h), Early (12–24 h), and Late (>24–138.5 h) Surgery with Magnetic Resonance Imaging-Confirmed Decompression in American Spinal Injury Association Impairment Scale Grades A, B, and C Cervical Spinal Cord Injury

“…7,[11][12][13] Compression of the spinal cord against an unyielding spinal canal results in increased intraspinal pressure and reduced perfusion pressure, further jeopardizing blood flow to the spinal cord. [14][15][16] In motor complete TSCI patients, swelling of the spinal cord spreads rostrally and caudally from the injury epicenter in fusiform fashion, 8 at a rate of *900 lm/h. 13,17 Frequently, by the time the victim is transferred to the trauma center, intramedullary lesion length (IMLL), can measure between 40 and 100 mm in length, far beyond the cross-sectional injury epicenter.…”

“…Recent efforts have begun to establish the significance of the extent of spinal cord decompression in neurological outcome. 16,35,42,43 Data reported by Aarabi and coworkers indicated that standard surgical management of cervical SCI achieves decompression of the entire swollen segment of the spinal cord in only 66% of subjects. 35 Additional studies incorporating post-operative MRI indicate that up to 25% of patients may need expansive duraplasty for adequate spinal cord decompression, along with reduction of intraspinal pressure, in order to improve functional outcome.…”