I reviewed the epidemiology and occurrence of traumatic cervical spine injuries of athletes in Japan and other countries, and noted the importance of initial assessment at the sports site, imaging diagnosis, and treatment of cervical spine injuries. From the global epidemiology of sports-related spinal cord injury, the frequency and cause of spinal cord injuries are different among countries, along with their respective characteristics. Taking prompt measures at the sports site is necessary to ensure safe patient handling and transport. However, as many people other than doctors are involved in sports events, the staff involved in these events should be prepared and practice emergency response measures. No major difference was found between athletes and non-athletes in regard to the treatment of cervical spine injury. However, athletes strongly hope for early return to active participation in their sport. Thus, surgical methods that are less invasive to soft tissues and involve strong fixation should be selected. However, further knowledge about evaluation and judgment for these athletes to return to their sport is needed. Many sports-related spinal cord injuries are preventable, and we must strive toward achieving zero incidence of spinal cord injuries. Thus, physicians attending to sports-related spinal cord injuries should both communicate more actively and supervise players of the team.

  Purpose : This retrospective study was designed to compare fusion rate and time to bone fusion using titanium cages filled with β-tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) /collagen composite of patients undergoing anterior cervical discectomy and fusion (ACDF).

  Methods : ACDF was performed in 63 patients at one or two levels using titanium cages filled with β-TCP or HAp/collagen composite. Bony fusion was retrospectively assessed via radiography at 3, 6, and 12 months postoperatively.

  Results : In the β-TCP group, 18 (95%) of 19 patients showed bony fusion in the last follow-up : six patients (32%) at 6 months postoperatively, and the remaining 12 (63%) at 12 months. In the HAp/collagen composite group, 43 (98%) of 44 patients showed bony fusion at the last follow-up : two (4.5%) at 3 months postoperatively, 27 (61%) at 6 months, and the remaining 14 (32%) at 12 months.

  Conclusion : No differences in fusion rate were evident between the β-TCP group and HAp/collagen composite group when observed for 1 year, although the HAp/collagen composite group showed shorter time to bone fusion compared with the β-TCP group.

  Objective : Achondroplasia is the most common heritable skeletal dysplasia. Cervicomedullary compression at the foramen magnum is highly associated with severe neurological complications including sudden death. Distinguishing which patients are at a high risk of neurological compromise is difficult. The aim of this study is to clarify the radiological features of the foramen magnum in achondroplasia that requires surgical decompression.

  Materials and methods : We conducted a retrospective study at our department with regard to the radiological features of the foramen magnum in achondroplasia, including the sagittal diameters of the cervicomedullary junction, arachnoid space on magnetic resonance imaging (MRI), and the basion-opisthion interval on computed tomography (CT). We also measured the cross-sectional area of the cervicomedullary junction, arachnoid space on MRI, and foramen magnum on CT. Patients’ data were classified into operative and non-operative groups. From January 2012 to December 2015, nine children with achondroplasia were initially evaluated radiologically. The mean age at initial evaluation was 11.6 months, and the mean follow-up period was 33.1 months. Foramen magnum decompression was indicated for children with morphological change of the cervicomedullary junction under compression or intramedullary signal change on MRI.

  Results : Seven of nine patients underwent foramen magnum decompression. The remaining two were managed conservatively. In the operative group, we found smaller sagittal diameter of the cervicomedullary junction and arachnoid space on MRI, but were not statistically significant (p=0.0556 and 0.0556, respectively). Besides, the operative group showed smaller cross-sectional area of the foramen magnum on CT, which was also insignificant statistically (p=0.0556). The morphological comparison of the foramen magnum on CT showed insufficient expansion of the posterior margin on the operative group. This anatomical feature caused ventral projection and dorsal compression to the cervicomedullary junction.

  Conclusions : The smaller size of the foramen magnum in children with achondroplasia can be related to cervicomedullary signal change or compressive deformity on MRI. Further study is necessary to establish the surgical criteria for foramen magnum decompression in children with achondroplasia.

  Objective : Odontoid fractures are the most common cervical injuries among the elderly population. We evaluated treatment outcome in 14 patients with odontoid fractures who were treated at our institute between 2003 and 2016. Additionally, in this report, we discuss the optimal treatment option for odontoid fractures in the elderly population and provide a literature review.

  Results : Patient age ranged 19-90 (average, 60.6) years, and the patients included five (36%) octogenarians. According to Anderson’s classification, four cases (29%) were type II and 10 cases (71%) were type III odontoid fractures. Surgical intervention was performed in 12 cases, including anterior odontoid screw fixation in nine, posterior cervical instrumented fusion in four (including reoperation after anterior screw fixation in one), and conservative treatment with halo vest fixation in two. Moreover, 13 patients received radiographic follow-up, and 11 (85%) attained bone fusion. In octogenarians, three (60%) of five cases attained bone fusion through anterior screw fixation.

  Conclusion : In the elderly population, tailor-made treatment is necessary according to systemic diseases, activities of daily living, and radiographic assessment of odontoid fractures in addition to Anderson’s classification.

  Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive spinal technique. PELD can be performed using the transforaminal (TF) or interlaminar (IL) approach. The TF approach is a well-established modality in the treatment of patients with a herniated lumbar disc. This technique makes the most of the space within the intervertebral foramen, where Kambin’s triangle permits a safe approach to the lesion.

  Knowledge of the anatomy of the lumbar artery and its branches and the ligaments of the intervertebral foramen is necessary to perform successful surgery and avoid complications.

  Background : The ideal surgical approach for cervical radiculopathy remains elusive. Posterior endoscopic cervical foraminotomy (PECF) is minimally invasive. This technique can preserve cervical range of motion and reduce adjacent segment degeneration. We report the results for cervical radiculopathy treated with PECF.

  Methods : PECF was performed on 5 patients (2 men and 3 women ; mean age, 51.8 years ; range, 40-65 years). Affected cervical levels included C5/6 (2 patients), C6/7 (2 patients), and C7/T1 (1 patient). Patients had cervical radiculopathy due to single-level, unilateral foraminal stenosis or soft-disc herniation. Clinical status was evaluated preoperatively and 1-month postoperatively using the neck disability index (NDI), the Japan Orthopaedic Association (JOA) score, and the numerical rating scale (NRS) for neck and arm pain.

  Results : The NDI was improved after surgery. The mean JOA score recovery rate was 92.5% (80-100%). Complete relief of radiculopathic neck pain (NRS 0) and complete or partial improvement in arm pain (NRS 0-2) were observed in these patients.

  Conclusion : Advantages of PECF for treatment of cervical radiculopathy included a small skin incision and minimum facet joint resection when decompressing the cervical nerves. We advocate PECF as an alternative surgical intervention for cervical radiculopathy. Appropriate surgical indications and meticulous endoscopic technique are mandatory to achieve satisfactory outcomes.

  A 56-year old man who underwent posterior fixation with vertebroplasty using hydroxyapatite (HA) blocks for an L4 burst fracture developed fever and worsening low back pain 19 days after surgery. We suspected a surgical site infection, but initial imaging studies did not identify a focus. A few weeks later, the affected vertebral body collapsed and HA blocks were found scattered along the psoas major muscle, suggesting the incidence of surgical site infection. Debridement of HA blocks and anterior fixation with autologous bone grafting were performed due to instability. Intraoperative computed tomography (CT) with a navigation system was useful for detecting and removing HA blocks in the adherent psoas muscle. On day 11 after the second operation, high fever, altered consciousness, muscle rigidity, tremor, tachycardia, hypertension, diaphoresis, and an elevated creatine phosphokinase level were observed. The patient was diagnosed with neuroleptic malignant syndrome (NMS), and was treated with sodium dantrolene, bromocriptine, and diazepam.

  Surgical site infection (SSI) after spinal instrumentation surgery can result in serious secondary complications, including neurological disorders, sepsis, and death. Deep incisional SSI without obvious superficial manifestations is sometimes difficult to diagnose, especially after vertebroplasty. We describe a rare case of vertebral infection after vertebroplasty using HA blocks. The infection was successfully treated using intraoperative CT with a navigation systems to remove the HA blocks.

  Although NMS is rare, it is a potentially fatal condition that occurs in association with the use of neuroleptic medications. Among patients with spinal disorders, it is not uncommon to find those with psychiatric disorders or those who use causative drugs. Surgery, dehydration, poor nutritional status, and infections are possible risk factors, and spinal surgeons should consider NMS in the differential diagnosis.