A Surgical Method for Determining Proper Screw Length in ACDF

OBJECTIVE: We describe a surgical tool that uses the distractor pin as a reference for determining proper screw length in ACDF. It is critical that screw purchase depth be as deep as possible without violating or penetrating the posterior cortical wall, which ensures strong pull out strength. METHODS: We enrolled 81 adult patients who underwent ACDF using an anterior cervical plate from 2010 to 2012. Patients were categorized into Groups A (42 patients: retractor pin used as a reference for screw length) and B (39 patients: control group). Intraoperative lateral x-rays were taken after screwing the retractor pin to confirm the approaching vertebral level. The ratio of retractor pin length to body anteroposterior (A-P) diameter was measured as a reference. Proper screw length was determined by comparison to the reference. RESULTS: The average distance from screw tip to posterior wall was 3.0+/-1.4mm in Group A and 4.1+/-2.3mm in Group B. The ratio of screw length to body sagittal diameter was 86.2+/-5.7% in Group A and 80.8+/-9.0% in Group B. Screw length to body sagittal diameter ratios higher than 4/5 occurred in 33 patients (90%) in Group A and 23 patients (59%) in Group B. No cases violated the posterior cortical wall. CONCLUSION: We introduce a useful surgical method for determining proper screw length in ACDF using the ratio of retractor pin length to body A-P diameter as a reference. This method allows for deeper screw purchase depth without violation of the posterior cortical wall.

Box-Shape Cervical Expansive Laminoplasty: Clinical and Radiological Outcomes

OBJECTIVE: Box-shape cervical expansive laminoplasty is a procedure that utilizes a Miniplate(R) or Maxpacer(R) to achieve maximal canal expansion. This method is expected to show much larger canal expansion and good clinical outcome. So we investigated the clinical and radiological outcome of Box-shape cervical expansive laminoplasty. METHODS: Between June 2008 and July 2013, we performed cervical expansive laminoplasty in 87 and 48 patients using the Box-shape cervical expansive laminoplasty, respectively. We analyzed the clinical results of these operations using the Japanese Orthopedic Association (JOA) scoring system and by assessing the position of intralaminar screws with postoperative computed tomography (CT) at POD-6 months. RESULTS: A total of 48 patients with ossification of the posterior longitudinal ligament (OPLL) (36 pts), cervical spondylotic myelopathy (CSM) (12 pts) were enrolled. Overall JOA scores improved from 11.49 to 14.22 at POD-6 months (OPLL: 11.32 -->14.3; CSM: 12-->14). Postoperative CT scans were performed in 39 patients at 177 levels for a total of 354 screws. The malpositioning rate of intralaminar screws was 3.4% and hardware-related neurologic complications did not occur. CONCLUSION: Box-shape cervical expansive laminoplasty creates maximal spinal canal expansion and leads to improved cervical myelopathy. The use of intralaminar screws to fix the remodeled lamina-facet does not represent a significant difficulty.

Adult-Onset Sellar and Suprasellar Atypical Teratoid Rhabdoid Tumor Treated with a Multimodal Approach: A Case Report

We report a very rare case of sellar and suprasellar atypical teratoid rhabdoid tumor (ATRT) in a 42-year-old female patient. The tumor was removed subtotally with a transsphenoidal approach. Histopathologic study showed rhabdoid cells with prominent nucleoli and abundant cytoplasm. Immunohistochemistry for INI1 was completely negative in the tumor cells, consistent with ATRT. After surgery, she received radiotherapy including spinal irradiation with proton beam therapy and subsequent chemotherapy, with no evidence of recurrence for more than 2 years. Up to date, this is the 8th case of an adult-onset ATRT in the sellar or suprasellar region. Despite its rarity, ATRTs should be considered in the differential diagnosis of an unclear malignant sellar or suprasellar lesion in adult patients and the treatment strategies for adult ATRT patients could be differentiated from those of pediatric ATRT patients.