In this review article, we compare the operative outcomes and minimal invasiveness of full-endoscopic discectomy (FED) and microendoscopic discectomy (MED). Data were reviewed mainly from recent meta-analyses. We also summarized our previous experiences with FED and MED and attempted to clarify the differences between these two techniques. The operative outcomes were found to be almost identical in both groups. There were fewer postoperative complications with FED than with MED in both previous studies and in our experience. Furthermore, FED was superior to MED at preventing disc height loss, which is an indicator of postoperative disc degeneration. Therefore, we recommend FED as the first option for the treatment of lumbar disc herniation, because it has a better safety profile and is minimally invasive.

  Objective : This study aimed to reveal the factors associated between low back pain (LBP) and cervical spondylotic myelopathy (CSM) by analyzing preoperative clinical characteristics and surgical outcomes.

  Methods : We retrospectively analyzed 67 patients with LBP among 285 patients with CSM who underwent cervical laminoplasty treated in 2014-2020. Of them, 67 patients with a visual analog scale (VAS, 0-100) score for LBP of ≥30 were included. Data including age, sex, Japanese Orthopaedic Association (JOA) Cervical Myelopathy Evaluation Questionnaire (CMEQ) scores, JOA Back Pain Evaluation Questionnaire (BPEQ) scores, VAS, Neck Disability Index (NDI) scores, and Oswestry Disability Index (ODI) were analyzed. Statistical analyses were performed of surgical outcomes using the Kruskal-Wallis test and Dunnett test. A forward stepwise logistic regression was used to identify possible predictors of the rate of improvement of LBP of the candidate variables at 1 month and 1 year after the cervical laminoplasty. The variables with values of p＜0.001 were identified after the multivariable logistic regression for the chosen variables using the stepwise method.

  Results : Cervical JOA score significantly improved from 12.2±4.0 preoperative to 13.6±3.4 (p=0.03) at 1 month postoperative and to 14.4±3.0 (p＜0.001) at 1 year postoperative. Clinical improvements were seen in JOA BPEQ scores and ODI but not in JOA CMEQ scores or NDI. VAS of LBP showed significant improvement from 56.8±18.9 preoperative to 34.0±30.6 (p＜0.001) at 1 month postoperative and 42.2±26.5 (p=0.002) at 1 year postoperative.

Multivariable logistic regression analysis following a forward stepwise logistic regression revealed the factors for the improvement rate of VAS scores for LBP after cervical laminoplasty. The factors at 1 month postoperative were preoperative JOA BPEQ score for walking ability (B=1.2, t=4.5), no lumbar spondylosis (B=51.7, t=4.0), and VAS scores for LBP (B=1.4, t=3.7). The factors at 1 year postoperative were preoperative no lumbar spondylosis (B=79.3, t=6.8), JOA CMEQ QOL scores (B=2.0, t=4.1), JOA BPEQ social life function scores (B=−1.6, t=−3.9), pain or numbness from chest to toe (B=−0.74, t=−3.8), and cervical JOA III scores (B=−25.7, t=−3.6).

  Conclusions : Preoperative clinical factors that improve LBP after cervical laminoplasty were : at 1 month postoperative, the patient has severe LBP but is ambulatory ; at 1 year postoperative, the patient’s LBP inhibits social function and reduces bladder function, but the psychological quality of life is maintained and there is less pain and numbness from chest to legs ; and factors that improve LBP throughout the year were no complications of lumbar spine lesions.

  The combination of lumbosacral spinal lipoma and spinal arteriovenous fistula (sAVF) is a rare and complicated pathological condition. Therefore, caution is required during diagnosis and treatment policy planning. Herein, we present two cases of AVF associated with lumbosacral spinal lipoma and a review of the literature.

  Both patients had a history of untethering surgery for lumbosacral spinal lipoma, with postoperative lower-limb symptoms and gait disturbance. Both patients also developed an arteriovenous fistula at the site of lumbosacral spinal lipoma excision. One patient was managed using endovascular treatment alone. However, in the other case, the lesion was intractable even after multiple operations. Ultimately, this pateient was treated using a combination of endovascular treatment and surgery.

  Although congenital malformations are usually associated with arteriovenous malformations, sAVF is associated with acquired factors such as trauma, surgery, or venous thrombosis.

  Previous reports suggest that the lipoma itself penetrates the dura and may be involved in the formation of fistulas.

  Because there is no definite consensus at this time, it is necessary to carefully consider the treatment strategy for arteriovenous fistula associated with lumbosacral spinal lipoma.

  Purpose : Fibrocartilaginous embolism (FCE) causing spinal cord ischemia is poorly understood. Although rare, its clinical impact is significant due to rapid progression of motor paralysis despite minor trauma. Here we report a case of FCE. Case Presentation : A 23-year-old man without a significant prior medical history experienced lower-limb numbness and lumbar pain 15min after falling on his buttocks, with paraplegia and bladder and rectal dysfunction developing 1 h later. Proprioception was retained. Intramedullary high-intensity signals within the spinal cord from T8 to the conus medullaris were detected on T2-weighted magnetic resonance imaging (MRI). Suspecting spinal cord ischemia in the anterior spinal artery area, we initiated treatment with steroids, edaravone, aspirin, and hyperbaric oxygen therapy, considering the possibility of myelitis and demyelinating diseases. Subsequently, aortic dissection and other vascular abnormalities were ruled out by contrast computed tomography, and coagulation abnormalities, vasculitis, immune and demyelinating diseases were ruled out by blood tests and cerebrospinal fluid analysis. Intramedullary high-intensity signals on diffusion-weighted imaging and low signal changes on apparent diffusion coefficient MRI were observed. On contrast-enhanced MRI, no contrast-enhanced lesions were observed. The patient was able to walk with a cane at 37 days post-injury, and the neurological deficits disappeared after 3 months. Discussion : Although veterinary medical literature has reported more cases in various animals, it is difficult to make a histological diagnosis of FCE in humans because it requires a spinal cord biopsy. Therefore, it is necessary to make a diagnosis primarily through the exclusion of conditions such as infection, myelitis, vasculitis, coagulation disorders, and demyelinating diseases based on the characteristic clinical course, neurological symptoms in the anterior spinal artery area, and abnormal findings consistent with vascular distribution mainly on axial MRI. The pathophysiological mechanism involves intervertebral disc components entering the spinal cord microcirculation due to increased intradiscal pressure, then retrogradely flowing into the radicular arteries, causing embolization in the anterior spinal artery area. Treatment methods are lacking, and prognostic reports are inconsistent. It is important to be aware of the possibility of FCE and accumulate further case studies in the future.

  We report a case of spinal radicular arteriovenous fistula (SRAVF) at the lower cervical region in an 80-year-old woman who presented with a sudden onset of headache and nausea due to subarachnoid hemorrhage (SAH). Initial computed tomography (CT) showed an SAH mainly in the posterior cranial fossa. 3D-CT angiography (CTA) showed no intracranial aneurysm or dissection. The angiogram showed that the left C7 radiculomedullary artery (RMA) joined the anterior spinal artery (ASA), which supplied a feeding artery toward the AV shunt point at the left C8 level and a draining vein toward the cranial side from the shunt point. The feeding artery had an aneurysm, and there was no left C8 RMA. The preoperative diagnosis was SAH due to spinal perimedullary AVF, prompting a direct anterior approach on day 29.

  Intraoperative findings showed that the feeding artery from the ASA ran to the left side. An aneurysm was located in front of the spinal cord, and the AV shunt was found on the C8 nerve root, leading to the diagnosis of renal arteriovenous fistula (RAVF). To preserve the function of the left C8 nerve root, we did not cauterize the shunt on the nerve root but performed trapping of the aneurysm as proximal occlusion of the AVF. Intraoperative angiography confirmed the disappearance of the AV shunt. The postoperative course was uneventful; CTA one year after surgery showed no recurrence of the AVF.

  RAVF of the mid or lower cervical spine is rare, and its standard treatment has not been established. Detailed preoperative examination, including cone-beam CT and selective angiography, is useful for accurate diagnosis and appropriate treatment.