Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Spine
Abstract number: 24366
CONJOINED LUMBOSACRAL NERVE ROOT: THREE CASES OF
INTRAOPERATIVE DETECTION
Yuichiro MORISHITA, Hideki OHTA, Yoshiyuki MATSUMOTO, George HUANG,
Tsubasa SAKAI, Yoshiharu TAKEMITSU, Hirotaka KIDA
Oita Orthopaedic Hospital, Oita (JAPAN)
Introduction: Conjoined nerve root are often missed even with advanced imaging
studies. The majority of conjoined nerve root occurs unilaterally at L5-S1. We report
three cases of unsuspected conjoined nerve root which were detected
intraoperatively. Material & Methods: A total of 78 microendoscopic discectomy
(MED) were performed over one year between January 2009 and December 2009.
All patients were diagnosed as lumbar disc herniation preoperatively by means of
MRI, myelogram, and myelo-CT. None of the subjects were diagnosed with
conjoined nerve root anomalies preoperatively. Results Three out of 78 patients were
found to have conjoined lumbosacral nerve root anomaly intraoperatively. All patients
were male, and all demonstrated L5-S1 herniated disc (one was subligamentous
extrusion and 2 were transligamentous extrusion). All subjects showed Type 2A of
S1 conjoined nerve root based on the classification of Neidre. After surgery, all
subjects showed excellent clinical results. Discussion: The lack of a preoperative
awareness of conjoined nerve root may lead to iatrogenic root injury. It is said that
these potential failure may increase with the rising popularity of minimally invasive
therapies to the sacrifice of enhanced visualization. In our study, 2.6% of
unsuspected conjoined nerve roots were detected intraoperatively. None of them
demonstrated pseudolocalizing neurological sign preoperatively, and preoperative
diagnostic images did not clearly identify nerve root anomalies. A surgeon must
always be cognizant of the fact that a nerve root anomaly may be present during any
surgical exploratory procedure.
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