Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, the elderly, and Asian patients. There are many diseases associated with OPLL, such as diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, and other spondyloarthropathies. Several factors have been reported to be associated with OPLL formation and progression, including genetic, hormonal, environmental, and lifestyle factors. However, the pathogenesis of OPLL is still unclear. Most symptomatic patients with OPLL present with neurological deficits such as myelopathy, radiculopathy, and/or bowel and bladder symptoms. There are some reports of asymptomatic OPLL. Both static and dynamic factors are related to the development of myelopathy. Plain radiography, CT, and MR imaging are used to evaluate OPLL extension and the area of spinal cord compression. Management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be made case by case, depending on the patient's condition, level of pathology, type of OPLL, and the surgeon's experience. In this paper, the authors attempt to review the incidence, pathology, pathogenesis, natural history, clinical presentation, classification, radiological evaluation, and management of OPLL.

Object This study analyzes 84 cases of peroneal nerve injuries associated with sports-related knee injuries and their surgical outcome and management. Methods The authors retrospectively reviewed the cases of peroneal nerve injury associated with sports between the years 1970 and 2010. Each patient was evaluated for injury mechanism, preoperative neurological status, electrophysiological studies, lesion type, and operative technique (neurolysis and graft repair). Preoperative status of injury was evaluated by using a grading system published by the senior authors. All lesions in continuity had intraoperative nerve action potential recordings. Results Eighty-four (approximately 18%) of 448 cases of peroneal nerve injury were found to be sports related, which included skiing (42 cases), football (23 cases), soccer (8 cases), basketball (6 cases), ice hockey (2 cases), track (2 cases) and volleyball (1 case). Of these 84 cases, 48 were identified as not having fracture/dislocation and 36 cases were identified with fracture/dislocation for surgical interventions. Good functional outcomes from graft repair of graft length < 6 cm (70%) and neurolysis (85%) in low-intensity peroneal nerve injuries associated with sports were obtained. Recovery from graft repair of graft length between 6 and 12 cm (43%) was good and measured between Grades 3 and 4. However, recovery from graft repair of graft length between 13 and 24 cm was obtained in only 25% of patients. Conclusions Traumatic knee-level peroneal nerve injury due to sports is usually associated with stretch/contusion, which more often requires graft repair. Graft length is the factor to be considered for the prognosis of nerve repair.

268hospital and was classified as grade 1. An examination found hypoesthesia at the T8 level and below and the deep tendon reflexes were reduced. We performed a chest computed tomography (CT) scan, but aortic dissection was not observed. We suspected hypokalemic periodic paralysis of both lower extremities and conducted laboratory studies; however, the results were negative. We then suspected thoracic myelopathy and thus provided steroid mega-dose therapy and conducted magnetic resonance imaging (MRI). The motor paralysis was gradually relieved so that the motor function were grade 2 on the right side and grade 3 on the left side four hours after the onset of symptoms. It was grade 4 on both sides after five hours. The MRI showed acute subdural hematoma at levels C2-T6 (Fig. 1A, C). Paralysis almost completely disappeared by 55 hours after onset. A cervical MRI conducted at that time revealed reduced cervicaldorsal SSDH (Fig. 1B, D). Case 2A 38-year-old male patient experienced headache, back pain, cold sweating, and dizziness that began when he was lifting weights one month earlier. These symptoms were relieved after he was treated at a clinic of pain medicine near his home. Three days later, he came to the emergency room with vertigo, which was relieved with intravenous hydration. Approximately one month later, his chest and back pain was aggravated by stretching exercises and he came to the emergency room. A brain MRI with contrast enhancement was conducted, which revealed thickening of the dura mater. The patient was then admitted to the neurologic department of the hospital with suspected spontaneous intracranial hypotension. The chest and back pain worsened and INTRODUCTIONSpinal subdural hematoma (SSDH) is a rare condition in which the spinal subdural hematoma compresses the spinal cord and the cauda equina, causing symptoms that may occur in relation to trauma, hemostatic disorders, anticoagulant drug administration, arteriovenous malformations, tumors, and lumbar punctures. Various unknown causes of SSDH have also been reported 4,11) . Its clinical symptoms are sudden pain, hypesthesia, motor paralysis, and neurologic defects in some cases [4][5][6]8,11,13) . Treatment generally consists of surgical decompression 3,15) . We experienced two cases of nontraumatic acute spinal subdural hematoma (NASSDH), treated conservatively without surgery. CASE REPORT Case 1A 55-year-old female patient came to the emergency room due to serious back pain that occurred during sleep. The patient had a past history of taking antihypertensive drugs and drugs to treat diabetes mellitus. Blood tests conducted in the emergency room did not reveal anything in particular. Paralysis of both lower extremities occurred after the patient came to the Department of Neurosurgery, Ewha Womans University School of Medicine, Mokdong Hospital, Seoul, KoreaSpinal subdural hematoma (SSDH) is an extremely uncommon condition. Causative factors include trauma, anticoagulant drug administration, hemostatic disorders, and vascular disor...

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Object The thoracolumbar junction is frequently accessed through an anterolateral approach with the incision and muscle dissection extending from the lower thoracic region to the lateral border of the rectus abdominis muscle. This approach is frequently associated with the subsequent development of an unsightly and uncomfortable relaxation of the ipsilateral abdominal wall, or flank bulge, caused by denervation injury to the intercostal nerves. However, the etiology of this complication is not widely recognized by spine surgeons. The object of this study was to better define the relevant anatomy and innervation of the anterolateral abdominal wall musculature. Methods The authors performed 32 cadaveric dissections and 6 intraoperative electromyography (EMG) evaluations. Results The cadaveric dissection studies and intraoperative EMG evaluations provided detailed anatomy of the anterolateral abdominal wall and its innervation. Cadaveric dissections revealed that the most significant intercostal nerve contributions to the anterolateral abdominal wall arise from T11 and T12. Electrophysiological confirmation of these findings was accomplished through intraoperative stimulation in 6 patients undergoing anterolateral retroperitoneal approaches to the thoracolumbar junction. The authors confirmed T11 and T12 innervation of the anterolateral abdominal wall musculature by direct intraoperative EMG recording in all 6 patients. Conclusions The authors classified the 3 potential zones of injury that can be affected during an anterolateral approach to the thoracolumbar junction. Modifications to the operative technique are suggested to avoid the complication of flank bulge. The most significant intercostal nerve contributions to the anterolateral abdominal wall arise from T11 and T12.

Object. Anterior surgical approaches to the lumbosacral disc spaces are being undertaken with increasing frequency. This increase and the use of minimally invasive techniques themselves have the potential to raise the incidence of major vessel injuries. The purpose of this study was to determine the variability of the vascular anatomy anterior to the lumbosacral spine and to draw conclusions regarding surgical accessibility of the L5—S1 disc space. Methods. Thirty-five cadavers (age range at the time of death 31–87 years) were obtained to evaluate the anatomical features of iliac vessels with respect to the anterior approach to the lumbosacral spine. Direct measurement and morphological classification regarding the relations of these great vessels to the four arbitrary reference points of the lumbosacral disc space were performed. The mean width and height of the L5—S1 disc were 56.4 mm (range 41.6–65.4 mm) and 18.8 mm (range 10–24 mm), repectively. According to the authors' morphological classification, nine specimens (26%) were found to be Type A (standard), 12 (34%) Type B (narrow), two (6%) Type C (ajar), and 12 (34%) Type D (obstacle). Conclusions. The authors have noted quite a variation in the venous vascular anatomy anterior to the lumbosacral disc. During surgical planning for the anterior approach to the lumbosacral spine when using any technique, it is vital to assess carefully radiographic and neuroimaging studies to minimize potentially disastrous vascular complications.

Iatrogenic vascular injuries during lumbar disc surgery may occur rarely but they are serious complications, which can be fatal without appropriate management. Prompt diagnosis and management of these complications are imperative to prevent a desperate outcome. A 72-year-old female with proximal left common iliac artery iatrogenic injury during lumbar discectomy was successfully treated by percutaneous deployment of a stent graft in an emergency setting. Postprocedural angiogram demonstrated complete exclusion of the iliac artery laceration. The patient became hemodynamically stable. Two weeks later she complained of vascular claudication. Follow-up angiography revealed decreased arterial flow in the opposite common iliac artery. An additional kissing stent was inserted into the right common iliac artery and the symptoms of vascular claudication disappeared. Endovascular stenting offers a safe and effective method for the treatment of an iatrogenic arterial laceration, particularly in a critical condition. But, the contralateral iliac arterial flow should be kept intact in case of proximal iliac artery injury. Otherwise, additional treatments may be needed.

Objective : Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of Bryan ® cervical disc prosthesis. Methods : The authors retrospectively reviewed radiographic and clinical outcomes in 52 patients who received the Bryan ® Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of functional spine unit (FSU), and the C2-7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria, visual analogue pain scale (VAS) and neck disability index (NDI). Results : A total of 71 Bryan ® disc were placed in 52 patients. A single-level procedure was performed in 36 patients, a two-level procedure in 13 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria, and showed significant improvement by VAS and NDI score (p < 0.05). The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level (p < 0.05). 97% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 88.5% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 70% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 66.6% of the patients postoperatively. Conclusion : Arthroplasty using the Bryan ® disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although the early results are promising, this is a relatively new approach, therefore long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.