BackgroundWe wanted to investigate the results of surgical treatment and analyze the factors that have an influence on the neurologic symptoms and prognosis of spinal intradural extramedullary (IDEM) tumors.MethodsThe spinal IDEM tumor patients (11 cases) who had been treated by surgical excision and who were followed up more than 1 year were retrospectively analyzed. Pain was evaluated by the visual analogue scale (VAS) and the neurologic function was assessed by Nurick's grade. The pathological diagnosis, the preoperative symptom duration, the tumor location on the sagittal and axial planes and the percentage of tumor occupying the intradural space were investigated. In addition, all these factors were analyzed in relation to the degree of the preoperative symptoms and the prognosis. On the last follow-up, the MRI was checked to evaluate whether or not the tumor had recurred.ResultsThe most common diagnosis was schwannomas (73%), followed by meningiomas (18%). The percentage of tumor occupying the intradural space was 82.9 ± 9.4%. The VAS score was reduced in all cases from 8.0 ± 1.2 to 1.2 ± 0.8 (p = 0.003) and the Nurick's grade was improved in all cases from 3.0 ± 1.3 to 1.0 ± 0.0 (p = 0.005). The preoperative symptoms were correlated with only the percentage of tumor occupying the intradural space (VAS; r2 = 0.75, p = 0.010, Nurick's grade; r2 = 0.69, p = 0.019). One case of schwannoma recurred.ConclusionsThe degree of neurologic symptoms was correlated with the percentage of tumor occupying the intradural space. All the tumors were able to be excised through the posterior approach. The postoperative neurologic recovery was excellent in all the cases regardless of any condition. Therefore, aggressive surgical excision is recommended even for cases with a long duration of symptoms or a severe neurologic deficit.

Study DesignDescriptions of technical strategies to overcome pitfalls associated with early learning periods in biportal endoscopic spinal surgery (BESS).PurposeTo introduce BESS for lumbar spinal diseases (LSDs) and to inform certain challenges to be overcome in mastering the technique.Overview of LiteratureBESS has shown superior benefits including excellent magnification, a wider range of view by dynamic handling of an endoscope and instruments. Clinical reports, however, have not yet been very revealing for its new introduction into minimally invasive spine surgery.MethodsTo evaluate the learning curve for BESS, the procedures for various LSDs by one surgeon were analyzed in the view of shortening of the operating times and reduction of complications. Reviewing of recorded procedures helped in finding the reasons and the implemented solutions.ResultsThe 68 cases included 25 for lumbar disc herniation (LDH), 3 for revision for recurred LDH, 39 for lumbar spinal stenosis (LSS) and 1 for synovial cyst. The operation time for the total cases averaged 83.7±33.6 minutes. According to diagnosis, it was 68.2±23.7 minutes for LDH. After the 14th case of LDH, it was nearly constant and close to the average time. One level of LSS needed 110.4±34.4 minutes. Prolonged operation times even in some later cases of LSS were mainly from struggling against blurred vision due to epidural bleeding. There were 7 cases of complications (10.3%) including 2 cases of dural tear, 1 case of root injury, and 4 cases of incomplete decompression on postoperative magnetic resonance imaging. There was no case of symptomatic hematoma or wound infection.ConclusionsBESS seemed to have a relatively short learning curve period. The overall complication rate in early learning period was 10.3%. These could be avoided by magnified regional views on an endoscope and a clear surgical field by controlling epidural bleeding.

BackgroundPrevalent endoscopic spine surgeries have shown limitations especially in spinal stenosis (Ahn in Neurosurgery 75(2):124–133, 2014). Biportal endoscopic surgery is introduced to manage central and foraminal stenosis with its wide range of access angle and clear view.MethodsThe authors provide an introduction of this technique followed by a description of the surgical anatomy with discussion on its indications and advantages. In particular, tricks to avoid complications are also presented.ConclusionsEffective circumferential and focal decompression were achieved in most cases without damage to the spinal structural integrity with preservation of muscular and ligamentous attachments. The biportal endoscopic spinal surgery (BESS) may be safely used as an alternative minimally invasive procedure for lumbar spinal stenosis (Figs. 1 and 2).Electronic supplementary materialThe online version of this article (doi:10.1007/s00701-015-2670-7) contains supplementary material, which is available to authorized users.

BackgroundTo examine the survival function and prognostic factors of the adjacent segments based on a second operation after thoracolumbar spinal fusion.MethodsThis retrospective study reviewed 3,188 patients (3,193 cases) who underwent a thoracolumbar spinal fusion at the author's hospital. Survival analysis was performed on the event of a second operation due to adjacent segment degeneration. The prognostic factors, such as the cause of the disease, surgical procedure, age, gender and number of fusion segments, were examined. Sagittal alignment and the location of the adjacent segment were measured in the second operation cases, and their association with the types of degeneration was investigated.ResultsOne hundred seven patients, 112 cases (3.5%), underwent a second operation due to adjacent segment degeneration. The survival function was 97% and 94% at 5 and 10 years after surgery, respectively, showing a 0.6% linear reduction per year. The significant prognostic factors were old age, degenerative disease, multiple-level fusion and male. Among the second operation cases, the locations of the adjacent segments were the thoracolumbar junctional area and lumbosacral area in 11.6% and 88.4% of cases, respectively. Sagittal alignment was negative or neutral, positive and strongly positive in 47.3%, 38.9%, and 15.7%, respectively. Regarding the type of degeneration, spondylolisthesis or kyphosis, retrolisthesis, and neutral balance in the sagittal view was noted in 13.4%, 36.6%, and 50% of cases, respectively. There was a significant difference according to the location of the adjacent segment (p = 0.000) and sagittal alignment (p = 0.041).ConclusionsThe survival function of the adjacent segments was 94% at 10 years, which had decreased linearly by 0.6% per a year. The likelihood of a second operation was high in those with old age, degenerative disease, multiple-level fusion and male. There was a tendency for the type of degeneration to be spondylolisthesis or kyphosis in cases of the thoracolumbar junctional area and strongly positive sagittal alignment, but retrolisthesis in cases of the lumbosacral area and neutral or positive sagittal alignment.

The infection rate of PLIF was higher than that of PF or PLF. Considering the increased infection rate in local bone grafted group and 52% of the infection cases after interbody fusion was osteomyelitis around interbody space, contaminated local bones and interbody space were suspected as major routes of contamination. The higher infection rate in single cage group than that of double cage group was attributed to vulnerability of remained avascular disk materials to infection.