Document Detail


A modern theory of paraplegia in the treatment of aneurysms of the thoracoabdominal aorta: An analysis of technique specific observed/expected ratios for paralysis.
MedLine Citation:
PMID:  19394541     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To demonstrate that a modern theory of paraplegia prevention in thoracoabdominal aortic (TAAA) surgery is primarily non-anatomic and derives from experimentally validated interventions that prolong the ischemic tolerance, reduce reperfusion injury, and enhance the collateral perfusion of the spinal cord with or without assisted circulation.
METHODS: Using an accurate predictive model (r(2) > 0.95) for paraplegia risk we studied the effects of protective strategies in 82 clinical series reporting more than 15,000 patients treated from 1985 to 2008. The observed/expected (O/E) ratios were calculated for each series and the results were grouped by technique. The effect of interventions such as spinal fluid drainage (SFD), systemic hypothermia, epidural cooling, and naloxone on O/E ratios were studied. We analyzed changes in O/E ratios from Era 1 (1985 to 1997) to Era 2 (1997 to 2008) and within treatment techniques over time.
RESULTS: The mean O/E ratio for paraplegia for all patients declined from 1.13 in Era 1 to 0.26 in Era 2. Adding SFD to patients treated with assisted circulation (AC) decreased the O/E ratio from 1.03 to 0.24 (P < .0001). Adding SFD to patients treated with aortic clamping without AC (XCL) decreased O/E from 0.91 to 0.23 (P = .0013). O/E for hypothermic arrest (HA) declined from 0.42 to 0.14 with SFD. The addition of SFD to AC, XCL, and HA accounted for most of the decline in O/E between Eras. Other factors which played a less defined but important role in the decline in O/E ratios were attention to higher mean arterial pressures (MAPs), more hypothermia, and neurochemical protection.
CONCLUSION: Paraplegia causation is anatomic but paraplegia prevention is physiologic (non-anatomic). We demonstrate that by using hypothermia, SFD, and increasing MAP, clinicians had similar improvements in paraplegia, reducing O/E deficit ratios from 1.03 to as low as 0.16, with or without intercostal reimplantation, and whether or not assisted circulation was used. Understanding the fundamental principles of paraplegia prevention and how to apply protective strategies leads to a reduction in paralysis in clinical series with or without the use of assisted circulation. This modern theory of paraplegia has significant implications for the rapidly advancing field of TAAA repair with branched endografts where the same principles apply.
Authors:
Charles W Acher; Martha Wynn
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of vascular surgery     Volume:  49     ISSN:  1097-6809     ISO Abbreviation:  J. Vasc. Surg.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-27     Completed Date:  2009-05-07     Revised Date:  2012-10-03    
Medline Journal Info:
Nlm Unique ID:  8407742     Medline TA:  J Vasc Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1117-24; discussion 1124     Citation Subset:  IM    
Affiliation:
Department of Surgery, University of Wisconsin, University of Wisconsin Hospital, Madison, Wisc. 53792-7375, USA. acher@surgery.wisc.edu
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MeSH Terms
Descriptor/Qualifier:
Aortic Aneurysm, Thoracic / surgery*
Assisted Circulation
Blood Pressure
Collateral Circulation
Constriction
Drainage / methods
Humans
Hypothermia, Induced
Logistic Models
Models, Biological
Naloxone / therapeutic use
Neuroprotective Agents / therapeutic use
Paraplegia / etiology,  physiopathology,  prevention & control*
Reperfusion Injury / etiology,  physiopathology,  prevention & control*
Risk Assessment
Spinal Cord Ischemia / etiology,  physiopathology,  prevention & control*
Time Factors
Treatment Outcome
Vascular Surgical Procedures / adverse effects*
Chemical
Reg. No./Substance:
0/Neuroprotective Agents; 465-65-6/Naloxone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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