The classification of spinal arteriovenous malformations (AVMs) is too complex to understand because of the numerous competing classification systems that have been proposed in the literature over time. Accordingly, English language literature regarding spinal AVMs between 1967 and 2015 were reviewed in order to clarify their historical changes. There were several major landmark papers and corresponding updates in classification : the first description of spinal dural arteriovenous fistulas (AVFs) and intradural AVMs diagnosed by spinal angiography in 1971, the second-generation classification based on the case report of intradural perimedullary AVFs treated by microsurgery in 1986, the third-generation classification based on the case series of intradural perimedullary AVFs treated by endovascular interventions in 1993, the forth-generation classification based on the case series of spinal AVMs treated by microsurgery and endovascular interventions in 2002, and the fifth-generation classification based on the case series of extradural AVFs treated by microsurgery in 2009 and endovascular interventions in 2011. Finally, the development of diagnostic imaging, microsurgery, and endovascular treatment for spinal AVMs have each contributed considerably to the historical changes in their classification system.
Performing surgery for spinal intramedullary tumors remains one of the major challenges for neurosurgeons, due to their relative infrequency, unknown natural history, and surgical difficulty. However, we are sure that the safe and precise resection of spinal intramedullary tumors, particularly encapsulated benign tumors, can result in acceptable or satisfactory postoperative outcomes. In this review article, we focused our attention on 5 important subjects : ①qualitative imaging diagnosis using positron emission tomography before surgery, ②the necessity and uncertainty of intraoperative neurophysiological monitoring, ③the importance of intraoperative image-guided surgery, ④careful selection of surgical access myelotomy, and finally ⑤dissection technique for tumors based on the tumor-cord interface. The risk of functional deterioration after surgery should be taken into serious consideration. Functional deterioration after surgery, including neuropathic pain even long after surgery, significantly affects patient quality of life. We firmly believe that the surgical goal for spinal intramedullary tumors is the better balance between tumor control and functional preservation that can be achieved not only by the surgical technique and expertise, but also by intraoperative neurophysiological monitoring, vascular image guidance, and postoperative supportive care.
The surgical treatment of intramedullary spinal cord tumors is associated with a 20% risk of persistent neurological morbidity. Accordingly, intraoperative neurophysiological monitoring is widely used to reduce the risk of neurological deterioration. It has been reported that motor evoked potential (MEP) monitoring has 100% sensitivity in detecting postoperative deterioration of motor function.
We have reviewed the results of 58 patients with intramedullary tumors who underwent 62 surgical procedures in our department during 2008-2011. Of those, MEP monitoring was performed in 59 surgeries, with recordings from 208 muscles. Correlation between intraoperative MEP findings and deterioration of muscle strength was retrospectively analyzed. The sensitivity of MEP monitoring in predicting postoperative weakness was 0.65, and specificity was 0.83.
Previous studies that claim 100% sensitivity of MEP monitoring treated select patients with an arbitrary definition of postoperative deterioration, so the findings are not reproducible in the common clinical situation. Intraoperative MEP monitoring provides useful information on the integrity of the motor pathway, but the decision to continue or abort tumor resection should not be completely dictated by it. Literature concerning the neuroanatomical and neurophysiological basis of MEP monitoring is also reviewed.
Microsurgical discectomy is the gold standard treatment for the herniated nucleus pulposus (HNP) of the lumbar spine. On the other hand, less invasive procedures have been developed and accepted rapidly. Percutaneous endoscopic lumbar discectomy (PELD) was developed as one of the minimally invasive techniques for HNP of the lumbar spine, and it was introduced to the Southern TOHOKU Healthcare Group in 2009. Herein we present our clinical experiences with PELD, and its surgical indications and current limitations are also discussed, reviewing the pertinent literature. PELD is usually carried out under local anesthesia, requiring only a stab wound for operation. Hospitalization may not be required, but in our practice, patients are advised to stay in the hospital at least for one day after the operation. A total of 71 patients were treated with PELD to date, and our surgical results have generally been satisfactory, except for 2 procedures which were discontinued due to the uncontrollable pain, and salvage operations were required in 9 of the 69 patients (13.0%) because of early recurrence, insufficient removal of the transligamentous disc fragment, and coexistent canal stenosis. These unfavorable events occurred in our earlier cases, and we no longer experience them recently. Although our experience is limited, PELD is a promising minimally invasive surgery for lumbar disc herniation. Recurrent disc herniation after microdiscectomy, high risk for general anesthesia, disc herniation at the L3-4 level or above, and emergency cases are considered to be the most ideal indications for this technique. On the contrary, patients with poor accessibility to the disc space or bony canal stenosis, large and hard HNP, or HNP with an up- or downward migration of more than 10 mm of the disc level, should be excluded from the surgical indication. Since PELD is a newer technique, continuous training and education are required for widespread implementation. Careful selection of the patients is crucial to achieve satisfactory surgical results, and certain criteria should be established.
Lumbar spinal fixation surgery is often selected to treat low back pain and the neurological symptoms of cauda equina and nerve root disorders. Lumbar spondylolisthesis, lumbar disc disease and foraminal stenosis, all of which have lumbar instability and bony degeneration, are indications for lumbar spinal fixation with interbody fusion, postero-lateral fusion and posterior fusion. Fixation surgery contributes to the improvement of low back pain and lower extremity pain in the short term, but if the procedure becomes complicated, the incidence of complications also increases, and adjacent spine degeneration becomes a problem in the long term. Therefore, it is important to be aware that surgical procedure selection is a major factor in the patient’s prognosis.
In this article, we describe the basic procedure for fixation in lumbar degenerative diseases, and describe the details of the procedure, such as posterior lumbar interbody fusion and postero-lateral fusion, based on the patient’s historical background. In addition, the recently developed minimally invasive techniques, such as the percutaneous pedicle screw, the cortical bone trajectory screw and lateral lumbar interbody fusion are discussed, and their features and effectiveness are explained.
Ganglioglioma was first described by Courville in 1930 and defined as a tumor containing both neuronal and glial components. Gangliogliomas account for 0.3-1.3% of all primary brain tumors. These tumors appear most commonly in the temporal lobe. Suprasellar gangliogliomas are quite rare, and only 15 cases have been reported to date. The suprasellar region is divided into the optic nerve/optic chiasma/hypothalamus and the corpus callosum/septum pellucidum. Previous reports have shown that suprasellar gangliogliomas are localized primarily in the optic nerve/optic chiasma/hypothalamus region.
No tumors have been described in the corpus callosum/septum pellucidum region. Here we present a case of suprasellar ganglioglioma in a 21-year-old woman. She presented with a gradually increasing headache over a period of 1 year. She was diagnosed with a brain tumor by her previous doctor, and was subsequently introduced to our department. CT and MRI demonstrated a suprasellar lesion with coarse calcification. The lesion displaced the third ventricle backward, and the bilateral lateral ventricles laterally, and obstructed the foramen of Monro, causing obstructive hydrocephalus. The lesion was completely removed by an interhemispheric approach. Because strong adhesion was observed between the lesion and the corpus callosum, the lesion probably arose from a site around the corpus callosum. Histopathological diagnosis was ganglioglioma. However, the neuronal component consisted of tumor cells of diverse stages of neuronal differentination, including well-differentiated ganglion cells, neurocytic cells, and small neuroblastic cells. To the best of our knowledge, this case is unique in both the location and differentiation status of the neuronal component.
Stenting may be effective for the treatment of traumatic pseudoaneurysms of the common carotid artery, but the few case reports utilized various procedures. A 78-year-old man fell from a stepladder, and the pruning shears in use penetrated the right side of the neck. Active bleeding from the open wound was controlled with compression. Computed tomography with contrast medium on admission revealed pseudoaneurysms of the common carotid artery, which gradually enlarged over 4 days. Coil embolization of the pseudoaneurysms assisted with three carotid artery stents was performed, which resulted in almost total disappearance of the pseudoaneurysms. The patient was discharged home with no neurological deficit. Follow-up neuroimaging revealed no recurrence of the pseudoaneurysms, and the patient was discharged with modified Rankin Scale score 0. Endovascular stenting and coiling is one of the most effective treatments for traumatic pseudoaneurysm of the common carotid artery, despite various problems such as administration of antithrombotic drugs, rebleeding, and retreatment.