Mitigating spinal cord distraction injuries: the effect of durotomy in decreasing cord interstitial pressure in vitro.
METHODS
The present study involved an in vitro examination of spinal cord interstitial pressure (CIP) during distraction before and after durotomy in three spinal cord segments obtained from five pigs.


OBJECTIVE
To determine whether durotomy can be used to decrease the elevated CIP associated with spinal cord distraction.


BACKGROUND
Spinal cord distraction is a known cause of spinal cord injury. Several articles describing the pathophysiology of cord distraction injuries suggest that the underlying mechanism of injury is a microvascular ischemic event. The authors have previously described an increase in CIP with spinal cord distraction, with average pressures of 23 mmHg at loads of 1,000 g. To date, there are no published studies that have evaluated the efficacy of intentional durotomies as a treatment for elevated CIP.


METHODS
A total of 15 spinal cord sections were harvested from pigs and distracted while immersed in saline, using a fixed 1,000 g distraction force. The CIP decay was then measured at 30-s intervals for 10 min. The distraction/relaxation maneuver was performed six times with continuous CIP monitoring and was subsequently followed by durotomy.


RESULTS
The pressure-decay curves were similar for each specimen, but varied according to individual pigs and anatomical levels. CIP decayed over the first 4 min of distraction and remained constant for the final 6 min. Longitudinal durotomy led to a dramatic drop in CIP toward baseline and appeared to be as effective as transverse durotomy with regard to the normalization of pressure.


CONCLUSIONS
Spinal cord distraction causes elevations in CIP. Durotomy lowers elevated CIP in vitro and may be effective at lowering CIP in vivo. Further study is required to evaluate the usefulness of durotomy in vivo.
Department of Orthopedic Surgery, College of Medicine, King Saud University, Riyadh, Saudi Arabia, wmawwad@gmail.com.
Waleed
W
Awwad
Mahdi
M
Bassi
Ian
I
Shrier
Abdulaziz
A
Al-Ahaideb
Russell J
RJ
Steele
Peter F
PF
Jarzem
D000818:Animals; D003161:Compartment Syndromes / Q000503:physiopathology / Q000601:surgery; D004388:Dura Mater / Q000601:surgery*; D066298:In Vitro Techniques; D019637:Orthopedic Procedures / Q000009:adverse effects*; D011312:Pressure; D013116:Spinal Cord / Q000601:surgery; D013119:Spinal Cord Injuries / Q000503:physiopathology / Q000601:surgery*; D013552:Swine