| 제목 | Neurosurgery: comments | ||
|---|---|---|---|
| 작성자 | 관리자 | 등록일 | 2013-07-05 |
내용
Neurosurgery 73:58-67, 2013
COMMENTS
Kwan Park
Sung-Tae Kim
Seoul, Korea
The authors presented the accuracy of the preoperative 3-dimensional (3-D) high resolution magnetic resonance imaging (MRI) to identify the offending vessels in hemifacial spasm with the references of the high definition neuroendoscopy. They also demonstrated very beautiful images of the endoscopic findings in the cerebellopontine area.
They categorized the compression into 2 types, simple and complex type which means multiple offenders around root exit zone of the facial nerve. Themean accuracy to detect the offending vessels of preoperative 3-DMRI was 80 to 84.7%depending on each observer group andmuch lower in the complex compression group. I agree with the authors’ opinion of difficulties in the detection of offenders especially in the complex cases. But considering inter-observer discrepancy of the accuracy in the complex group of this series and our experience, diagnostic accuracy may depend on the experience of observers. In addition, the complex type may have more variety other than tandem type.
They also described the vertebral artery (VA) was involved as an offender in only 1 out of 29 cases of the simple type and in 18 of 21 cases in the complex type. The rate of the VA involvement as offenders in this series is 38% which is higher than our series of 2,000 operated cases of hemifacial spasm, but I fully agree with the results of the VA involvement mainly in the complex type. These findings suggest that we need to search for 1 or more offenders in addition to the VA if the VA is suspected as an offender in the preoperative studies. In particular, the venous involvement as an offender is extremely low in my experience except in the cases of the pathological engorgement like venous anomaly.
The illustration of endoscopic view in this series including exposure of the entire course of the offending vessel from origin to compression site is very impressive. This can sometimes be difficult with the microscopic technique. Especially, in this series the high definition endoscopic findings are good references to identify offenders in cerebellopontine area. But the microscopic technique will do enough to detect every offender around the facial nerve root exit zone in practice. In addition, the efficacy or safety of the endoscopic technique for hemifacial spasm is not well established yet. Considering patient’s demand of high standards and the intrinsically very low complication rate of microvascular decompression procedures, the safety of the procedure cannot be overemphasized and the selection of the new procedures need thorough analyses with the extended series to verify long-term results and safety.
As authors’ description, the arteries and nerves cannot be discriminated in 3-D T2-weighted SSFP technique. That is why the combined use of 3-D TOF image is mandatory to evaluate neurovascular compression. Moreover, gadolinium-enhanced 3-D T1-weighted image is also helpful to identify other lesions like brain tumors or the venous offenders. Fusion images of the different techniques and multiplanar reconstructions can be helpful to visualize the complex neurovascular compression in hemifacial spasm.
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Value of 3-Dimensional High-Resolution Magnetic Resonance Imaging in Detecting the Offending Vessel in Hemifacial Spasm: Comparison With Intraoperative High Definition Endoscopic Visualization
Ehab El Refaee, MDNS, MSc, Soenke Langner, MD, Joerg Baldauf, MD, Marc Matthes, MSc, Michael Kirsch, MD, Henry W.S. Schroeder, MD,PhD
BACKGROUND: High-resolution 3-dimensional (3-D) magnetic resonance imaging (MRI) is widely used to predict the neurovascular anatomy within the cerebellopontine angle.
OBJECTIVE: To assess the value of 3-D steady-state free precession imaging (SSFP) and time-of-flight magnetic resonance angiography (TOF MRA) in detecting the offending vessels in hemifacial spasm in comparison to intraoperative endoscopic visualization.
METHODS: 42 patients underwent endoscope-assisted microvascular decompression (MVD). All available preoperative 3-D SSFP and TOF MRA images were checked. Intraoperative videos were captured by a high-definition endoscopic camera attached to endoscopes while exploring the area of facial nerve root exit zone (REZ). Evaluation of the 3-D images was performed by 2 independent groups of observers and compared with the operative findings.
RESULTS: Three-D MRI had an average positive predictive value (PPV) of 89.1% in differentiating between simple and complex compression. Mean accuracy of the images in detection of the offending vessels was 83.3% and 77% according to the first and second groups of observers, respectively. Averaged inter-observer agreement between the 2 groups of observers was substantial, with an averaged Kappa coefficient (K) of 0.56. In the simple compression group, mean accuracy was 97% and 89.4% according to the first and second groups of observers, respectively. Averaged K for agreement was substantial (K = 0.65).
CONCLUSION: According to endoscopic visualization, 3-D SSFP and TOF MRA images are accurate in detecting the offending vessels in simple compression of the facial nerve, and in predicting presence of a complex compression with variable sensitivity in identifying all offending vessels.
KEY WORDS: Hemifacial spasm, Endoscope assisted, Microvascular decompression, High resolution MRI
COMMENTS
Kwan Park
Sung-Tae Kim
Seoul, Korea
The authors presented the accuracy of the preoperative 3-dimensional (3-D) high resolution magnetic resonance imaging (MRI) to identify the offending vessels in hemifacial spasm with the references of the high definition neuroendoscopy. They also demonstrated very beautiful images of the endoscopic findings in the cerebellopontine area.
They categorized the compression into 2 types, simple and complex type which means multiple offenders around root exit zone of the facial nerve. Themean accuracy to detect the offending vessels of preoperative 3-DMRI was 80 to 84.7%depending on each observer group andmuch lower in the complex compression group. I agree with the authors’ opinion of difficulties in the detection of offenders especially in the complex cases. But considering inter-observer discrepancy of the accuracy in the complex group of this series and our experience, diagnostic accuracy may depend on the experience of observers. In addition, the complex type may have more variety other than tandem type.
They also described the vertebral artery (VA) was involved as an offender in only 1 out of 29 cases of the simple type and in 18 of 21 cases in the complex type. The rate of the VA involvement as offenders in this series is 38% which is higher than our series of 2,000 operated cases of hemifacial spasm, but I fully agree with the results of the VA involvement mainly in the complex type. These findings suggest that we need to search for 1 or more offenders in addition to the VA if the VA is suspected as an offender in the preoperative studies. In particular, the venous involvement as an offender is extremely low in my experience except in the cases of the pathological engorgement like venous anomaly.
The illustration of endoscopic view in this series including exposure of the entire course of the offending vessel from origin to compression site is very impressive. This can sometimes be difficult with the microscopic technique. Especially, in this series the high definition endoscopic findings are good references to identify offenders in cerebellopontine area. But the microscopic technique will do enough to detect every offender around the facial nerve root exit zone in practice. In addition, the efficacy or safety of the endoscopic technique for hemifacial spasm is not well established yet. Considering patient’s demand of high standards and the intrinsically very low complication rate of microvascular decompression procedures, the safety of the procedure cannot be overemphasized and the selection of the new procedures need thorough analyses with the extended series to verify long-term results and safety.
As authors’ description, the arteries and nerves cannot be discriminated in 3-D T2-weighted SSFP technique. That is why the combined use of 3-D TOF image is mandatory to evaluate neurovascular compression. Moreover, gadolinium-enhanced 3-D T1-weighted image is also helpful to identify other lesions like brain tumors or the venous offenders. Fusion images of the different techniques and multiplanar reconstructions can be helpful to visualize the complex neurovascular compression in hemifacial spasm.
--------------------------------------------------------------------------------------------------------------------
Value of 3-Dimensional High-Resolution Magnetic Resonance Imaging in Detecting the Offending Vessel in Hemifacial Spasm: Comparison With Intraoperative High Definition Endoscopic Visualization
Ehab El Refaee, MDNS, MSc, Soenke Langner, MD, Joerg Baldauf, MD, Marc Matthes, MSc, Michael Kirsch, MD, Henry W.S. Schroeder, MD,PhD
BACKGROUND: High-resolution 3-dimensional (3-D) magnetic resonance imaging (MRI) is widely used to predict the neurovascular anatomy within the cerebellopontine angle.
OBJECTIVE: To assess the value of 3-D steady-state free precession imaging (SSFP) and time-of-flight magnetic resonance angiography (TOF MRA) in detecting the offending vessels in hemifacial spasm in comparison to intraoperative endoscopic visualization.
METHODS: 42 patients underwent endoscope-assisted microvascular decompression (MVD). All available preoperative 3-D SSFP and TOF MRA images were checked. Intraoperative videos were captured by a high-definition endoscopic camera attached to endoscopes while exploring the area of facial nerve root exit zone (REZ). Evaluation of the 3-D images was performed by 2 independent groups of observers and compared with the operative findings.
RESULTS: Three-D MRI had an average positive predictive value (PPV) of 89.1% in differentiating between simple and complex compression. Mean accuracy of the images in detection of the offending vessels was 83.3% and 77% according to the first and second groups of observers, respectively. Averaged inter-observer agreement between the 2 groups of observers was substantial, with an averaged Kappa coefficient (K) of 0.56. In the simple compression group, mean accuracy was 97% and 89.4% according to the first and second groups of observers, respectively. Averaged K for agreement was substantial (K = 0.65).
CONCLUSION: According to endoscopic visualization, 3-D SSFP and TOF MRA images are accurate in detecting the offending vessels in simple compression of the facial nerve, and in predicting presence of a complex compression with variable sensitivity in identifying all offending vessels.
KEY WORDS: Hemifacial spasm, Endoscope assisted, Microvascular decompression, High resolution MRI
