Background : A four-point spinal frame helps to reduce blood loss during prone position surgery. Although effective in decreasing intra-abdominal and venous pressure, the resulting smaller areas of body surface contact have an increased risk of postoperative pressure ulcer formation. We report the results of our efforts to minimize the risk of ulcer formation in the last 5 years.

  Methods : Our basic idea was to pad the table with a foam sheet. In addition, the sheet was covered with sheepskin or paper toweling. We performed a retrospective analysis of medical records with special focus on whether a patient developed pressure injury from contact with the operating table. Patients were divided into three groups according to the body support method. The incidence of pressure injury was determined in each group.

  Results : When the total surgical time was less than 8 hours, our preventive method was effective in reducing intraoperative pressure injury from 27% to 18%. However, the incidence was 78% when the surgical time exceeded 8 hours, even with the newer preventive technique.

  Conclusion : This study showed that our approach to minimizing the risk of postoperative pressure injury using a combination of padding and covering was effective. However, surgical time was more strongly associated with the incidence of injury. Planning for a total surgical time of less than 8 hours should be considered.

  Purpose : We experienced 10 cases of ossification of the ligamentum flavum (OLF) and report the neuroradiologic and pathologic findings. The pathogenesis of OLF is discussed, and a literature review is provided.

  Materials and Methods : We treated 10 cases of thoracic OLF between 2010 and 2016. Neurologic symptoms and the Japanese Orthopaedic Association (JOA) score were evaluated. The postoperative recovery rate and JOA score (RR%) were calculated and compared with the preoperative results. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed, and all 10 cases underwent laminectomy. Pathologic findings were evaluated.

  Results : The age range of patients was 34-82 years, with 8 male and 2 female patients. All 10 cases developed myelopathy at the thoracic cord level. CT showed beak-like ossification extending to the intervertebral foramen. Pathologic findings demonstrated laminar ossification in the ligamentum flavum. Preoperative JOA scores ranged from 3 to 19 (mean : 9.3±5.1). One-year postoperative JOA scores ranged from 17 to 29 (mean : 23.4±4.7), and the RR% increased from 53.8 to 100 (mean: 71.3±11.5). Pathologic findings demonstrated laminar deposition of calcium phosphate in the intervertebral foramen. Chondrocytes enclosed by calcification and laminar hyaline cartilage were observed. Osteoblasts were observed in deposits of calcium phosphate.

  Conclusions : OLF is independent of spondylotic change and calcification of spinal ligaments. The neuroradiologic and pathologic findings suggested that chronic mechanical stimulation (compression and tension) of the ligament leads to gene expression and induction of transforming growth factors (e.g., bone morphogenetic growth factors, etc.), resulting in chondral ossification. Laminectomy for appropriate levels was effective.

  Introduction : Subpial spinal lipoma (SPL) is a rare tumor that must be differentiated from spinal lipoma in association with congenital anomalies. We report a subpial spinal lipoma in a 50-year-old male, and discuss the surgical treatment and outcome.

  Case presentation : A 50-year-old man visited our hospital with 1 year of gradually progressive weakness of his right lower leg and urinary incontinence. Magnetic resonance imaging showed a high-intensity lesion at the level of L3 on T1- and T2-weighted images. He was diagnosed with a lipoma and underwent partial resection under neurophysiologic sensory evoked potential, motor evoked potential, and nerve integrity monitoring. Five months after the operation, his symptoms had almost disappeared.

  Discussion : SPL is a slowly progressive lesion. The objective of treatment is to relieve compression on the spinal nerves. Radical excision of the tumor can worsen the symptoms and may not be necessary. Partial removal may be sufficient to control the symptoms and improve the outcome.

  Conclusion : Although more investigation is needed to determine definitive treatment and improve the long-term outcome of SPL, decompression of the conus medullaris and cauda equina under neurophysiological intraoperative monitoring can be attempted.

　　Intraspinal extradural meningeal cysts are rare and are defined as diverticula of the spinal meningeal sac, nerve sheath, or arachnoid. In general, a one-way valve mechanism at the dural defect is thought to be correlated with the formation and expansion of the cyst. We report successful treatment of a lumbar extradural meningeal cyst without an apparent one-way valve.

　　A 64-year-old woman presented with gradually progressive, intermittent sensory disturbance and paresis of the bilateral lower extremities, shortly after falling on her buttocks. Magnetic resonance imaging and computed tomography myelography showed an extradural meningeal cyst extending from L1 to L3 in the thoracolumbar region with a dural defect. Partial L1 to L3 laminectomy and left L2/3 facetectomy with posterolateral L2/3 fusion were performed. Operative findings revealed an oval dural defect measuring up to 4 mm that allowed two-way flow of cerebrospinal fluid between the extradural cyst cavity and the subarachnoid space. Surgical resection of the cyst wall and repair of the dural defect resolved the symptoms.

　　Draining and filling of fluid in the cyst with position changes possibly led to intermittent local compression of the dural sac, unlike local compression associated with a one-way valve mechanism at the dural defect. Surgery should be offered to patients with symptomatic extradural meningeal cysts.

  Objective : Venous hypertensive myelopathy (VHM) is classically associated with spinal dural arteriovenous fistula (AVF). We report a case of VHM due to ossification of the posterior longitudinal ligament (OPLL) at L1.

  Clinical presentation : A 66-year-old man presented with a 1-year history of progressive lower extremity paraparesis and bladder and rectal disturbance. Magnetic resonance imaging (MRI) and myelography performed at another hospital showed T2-weighted hyperintensity from T5 to the conus, with multiple areas of OPLL. The patient underwent L4/5 laminectomy and T10/11 pedicle screw insertion. However, the symptoms did not improve. He came to our hospital for a second opinion. Reevaluation of the myelogram performed at the previous hospital showed dilated and tortuous vessels on the surface of the spinal cord that had been overlooked. We suspected the existence of spinal dural AVF, and whole-spine computed tomography angiography (CTA), myelography, enhanced MRI, and angiography were performed, but no fistulas were found, although CTA and myelography revealed the dilated vessels. We decided to remove the pedicle screws and inspect the dura. After removing the screws, T10 to T12 laminectomies and upper L1 laminotomy were performed and the dura was opened. Engorged and tortuous vessels were observed on the dorsal surface of the cord. As indocyanine green showed dilated vessels in the venous phase without evidence of fistulas, we did not clip or coagulate any vessels. Because the conus appeared swollen, we closed with artificial dura. The postoperative clinical course was unexpected. Walking skill and bladder and rectal function improved. No dilated vessels were seen on myelography and CTA. MRI showed decreased T2-weighted hyperintensity (from T6 to the conus). We speculated that L1 laminotomy improved venous flow in the conus and led to clinical and radiologic improvement.

  Conclusion : To our knowledge, only 3 reports have described degenerative disease leading to VHM. This is the first report of VHM caused by OPLL, and the level of involvement was also unique. Our case indicates that spinal conus compression can be the cause of VHM. We suggest that spinal degenerative disease can be a rare but treatable cause of VHM.

  The incidence of cervical spine injuries (CSIs) among elderly patients is increasing in an aging society. An accurate diagnosis in the acute phase is important to avoid adverse clinical and sociolegal consequences. We present case reports of 2 elderly women who presented with cardiopulmonary arrest (CPA) with a delayed diagnosis of CSI. They presented with CPA of unclear etiology, and after successful cardiopulmonary resuscitation, a medical emergency team concluded that CPA in these patients was not trauma-related but was attributable to cardiovascular or endogenous pathology, because both patients showed only a few facial scars (which would rule out trauma). In both cases, cervical computed tomography performed after admission revealed atlantoaxial dislocation accompanied by typeⅡ odontoid fractures, confirming the diagnosis of upper CSI secondary to falls after CPA. Factors contributing to the diagnostic delay included lack of awareness regarding the following : (Ⅰ) bone fragility in elderly patients can cause serious CSIs even with low-energy trauma, (Ⅱ) CPA-related falls can cause CSIs and, (Ⅲ) superficial facial bruising can be the only external manifestation of CSIs. Upper CSIs should be considered as a complication of CPA, particularly in elderly patients presenting with even minor facial trauma.