Postoperative neurological deterioration in pediatric moyamoya disease: watershed shift and hyperperfusion

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Young patients with moyamoya disease frequently exhibit extensive cerebral infarction at the time of initial presentation, and even in the early postoperative period. To investigate clinical characteristics in the early postoperative period, the authors prospectively analyzed findings of MR imaging, MR angiography, and SPECT before and after surgery. The authors focused in particular on how postoperative neurological deterioration occurred.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Between August 2005 and June 2009, 22 patients younger than 18 years of age with moyamoya disease were treated at Miyagi Children's Hospital. The mean patient age (± SD) was 8.58 ± 4.55 years (range 2–17 years). Superficial temporal artery–middle cerebral artery bypass and indirect bypass of encephalosynangiosis between the brain surface and the temporal muscle, galea, and dura mater were performed in 35 hemispheres. Magnetic resonance imaging and MR angiography were performed before surgery, at 7 days postoperatively, and 3–6 months after surgery. A <jats:sup>123</jats:sup>I-isopropyl iodoamphetamine SPECT scan was also obtained pre- and postoperatively.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>During the postoperative period, neurological deterioration was observed after 15 operations (10 cases of motor paresis, 1 of aphasia, and 4 of sensory disturbance) in 13 patients. All symptoms had resolved by the time of discharge, except in 2 patients who suffered cerebral infarction. All patients exhibited disappearance (94.3%) or reduction (5.7%) of transient ischemic attacks (TIAs) during the follow-up period. Perioperative studies revealed 2 different types of radiological findings, focal uptake decrease on SPECT indicative of cerebral ischemia due to dynamic change in cerebral hemodynamics caused by bypass flow, the so-called watershed shift, and perioperative edematous lesions on MR imaging due to cerebral hyperperfusion. The frequent occurrence of preoperative TIAs was significantly associated with watershed shift, whereas preoperative MR imaging findings and preoperative SPECT findings were not. Age at operation was the only factor significantly associated with postoperative hyperperfusion.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>In young patients, moyamoya disease exhibits rapid progression, resulting in poor clinical outcome. The risk of postoperative neurological deterioration in very young moyamoya patients with frequent TIAs should be noted. The findings in this study showed that direct bypass is not completely safe in patients with moyamoya disease because it causes dynamic change in postoperative cerebral hemodynamics.</jats:p></jats:sec>

Current Status of Revascularization Surgery for Moyamoya Disease: Special Consideration for Its ‘Internal Carotid-External Carotid (IC-EC) Conversion’ as the Physiological Reorganization System

“…Regarding the perioperative cerebral infarction, following distinct pathologies are reported as the possible mechanisms underlying peri-operative ischemia. Firstly, Hayashi et al (2010) proposed 'watershed shift phenomenon' as an intrinsic hemodynamic ischemia at the adjacent cortex to the STA-MCA bypass for child-onset moyamoya disease. Retrograde blood supply from STA-MCA bypass may interfere with the anterograde blood flow from proximal MCA, and thus result in the temporary decrease in CBF at the cortex supplied by the adjacent branch of MCA.…”

“…Retrograde blood supply from STA-MCA bypass may interfere with the anterograde blood flow from proximal MCA, and thus result in the temporary decrease in CBF at the cortex supplied by the adjacent branch of MCA. The watershed shift phenomenon could lead to subsequent cerebral infarction among pediatric moyamoya disease (Hayashi et al 2010). Besides hemodynamic ischemia due to watershed shift phenomenon, thrombo-embolic complication originated from the anastomosed site (Fujimura et al 2008) and the mechanical compression by swollen temporal muscle flap could also cause cerebral ischemia in the acute stage (Fujimura et al 2009a).…”

Cerebral ischemia at early postoperative period of direct revascularization for moyamoya disease: a case report and literature review

“…[1,3] Rapid, increased local perfusion and perioperative hemodynamic fluctuations after bypass surgery might increase the risk of abnormal perfusion in the adjacent area or remote regions, especially in patients with advanced stage, bilateral, or unstable MMD. [8][9][10] In MMD with unilateral STA-MCA bypass, symptomatic cerebral ischemia in the contralateral hemisphere more commonly occurs in patients with advanced stage (Suzuki stage 4 to 6), PCA involvement and postoperative hypotension on postoperative Day (POD) 1 and Day 2. [7] Advanced Suzuki stage and PCA involvement indicate the progression of MMD.…”

“…[13] Moreover, the perfusion at different region might also be distinct during the same period of time. [10] CBF evaluation at the early postoperative period (POD 1 to 3) might be recommended to tailor the perioperative management based on the perfusion status. [15] The DWI and fluid attenuated inversion recovery (FLAIR) sequence could also be helpful to identify hyperperfusion and acute ischemia with typical radiological features.…”

“…Postoperative transient neurological events were reported to occur in 40-60% of revascularization surgery for MMD, [10] and 4-14% of patients exhibited postoperative cerebral infarction. [10,31] This report is congruent with previous observations that early postoperative neurological deficits usually resolve within 7 days, while irreversible cerebral infarction may persist in some patients with or without neurological deficits.…”