Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Michael H. Hsieh x
  • Refine by Access: all x
Clear All Modify Search
Restricted access

Michael H. Hsieh, Victor Perry, Nalin Gupta, Caroline Pearson, and Hiep T. Nguyen


Tethering of the spinal cord is a pathological fixation of the cord in the vertebral column that can result in neurogenic bladder dysfunction and other neurological problems. It occurs in patients with closed spinal dysraphisms and those in whom postoperative scarring develops following spina bifida closure procedures. The authors of this study sought to determine the effects of detethering on the urodynamic profile of children with a tethered cord.


The authors retrospectively reviewed the records of children who underwent surgical release of a tethered cord at a single institution between 2001 and 2003. They identified 17 children (nine girls and eight boys) who had undergone both preoperative and postoperative urodynamic evaluation.

Preoperatively, 10 (59%) of the children with a tethered cord had abnormal urodynamic study (UDS) results. Only two (20%) of these patients had urological symptoms. All seven patients with normal preoperative UDS results had normal UDS results after detethering. In addition, in five (50%) of the 10 children with abnormal preoperative UDS results, the postoperative UDS demonstrated improved or normal urodynamics.


Because more than half of the children who underwent detethering were found to have abnormal pre-operative UDS results, preoperative urodynamic evaluation should be performed in all cases in which detethering is considered. With regard to voiding function, detethering is relatively safe for children with normal preoperative UDS results. In children with abnormal preoperative UDS results, detethering may lead to improvement or even normalization of voiding, especially if the procedure is performed prior to 1 year of age. Finally, children with anorectal anomalies and a tethered cord may represent a subset of patients who are particularly likely to experience urodynamic improvement after detethering.

Full access

Lukas Andereggen, Sepideh Amin-Hanjani, Marwan El-Koussy, Rajeev K. Verma, Kenya Yuki, Daniel Schoeni, Kety Hsieh, Jan Gralla, Gerhard Schroth, Juergen Beck, Andreas Raabe, Marcel Arnold, Michael Reinert, and Robert H. Andres


Cerebral hyperperfusion syndrome (CHS) is a rare but devastating complication of carotid endarterectomy (CEA). This study sought to determine whether quantitative hemodynamic assessment using MR angiography can stratify CHS risk.


In this prospective trial, patients with internal carotid artery (ICA) stenosis were randomly selected for pre- and postoperative quantitative phase-contrast MR angiography (QMRA). Assessment was standardized according to a protocol and included Doppler/duplex sonography, MRI, and/or CT angiography and QMRA of the intra- and extracranial supplying arteries of the brain. Clinical and radiological data were analyzed to identify CHS risk factors.


Twenty-five of 153 patients who underwent CEA for ICA stenosis were randomly selected for pre- and postoperative QMRA. QMRA data showed a 2.2-fold postoperative increase in blood flow in the operated ICA (p < 0.001) and a 1.3-fold increase in the ipsilateral middle cerebral artery (MCA) (p = 0.01). Four patients had clinically manifested CHS. The mean flow increases in the patients with CHS were significantly higher than in the patients without CHS, both in the ICA and MCA (p < 0.001). Female sex and a low preoperative diastolic blood pressure were the clearest clinical risk factors for CHS, whereas the flow differences and absolute postoperative flow values in the ipsilateral ICA and MCA were identified as potential radiological predictors for CHS.


Cerebral blood flow in the ipsilateral ICA and MCA as assessed by QMRA significantly increased after CEA. Higher mean flow differences in ICA and MCA were associated with the development of CHS. QMRA might have the potential to become a noninvasive, operator-independent screening tool for identifying patients at risk for CHS.

Restricted access

Oral Presentations

2010 AANS Annual Meeting Philadelphia, Pennsylvania May 1–5, 2010