Search

BACKGROUND CONTEXT Occipitocervical fusion is a rare and often challenging surgical procedure. Significant morbidity can result if care is not taken to achieve physiologic alignment. This is especially true for patients needing occipitocervical fusion in the setting of trauma where preoperative alignment is unknown. PURPOSE To assess the radiographic angles normally subtended between the C2 body and the mandible ramus, in a series of patients with neutral physiologic alignment and no pathology, and to assess its validity as a possible intraoperative radiographic tool to determine a neutral craniocervical alignment. DESIGN Validation and reliability study of radiographic parameters. PATIENT SAMPLE Hundred lateral, neutral, cervical radiographs from patients with “normal” radiographic findings. OUTCOME MEASURES Radiographic parameters of occipital-cervical alignment with assessment of reliability and correlation in data. METHODS One hundred neutral lateral cervical spine radiographs in the upright position of patients with no complaints or known pathology were obtained from two medical clinics between December of 2014 and January of 2017. Three physicians, at different levels of spine surgery training, took measurements of radiographic parameters. The new technique used four different angles measured between the C2-body/dens complex and the mandibular ramus (anterior/posterior C2 body and anterior/posterior mandible lines angles), and compared these with the Occipito-C2 angle, which is a validated assessment of occipitocervical alignment. Statistical analysis was performed to assess correlation in data and measure reproducibility. RESULTS Between the three reviewers, the mean±standard deviation were 18.0°±6.5° for Occipito-C2 angle (O-C2A), −4.2°±5.4° for anterior C2-body/anterior mandible line angle (AB/AM), −4.2°±5.9° for anterior C2-body/posterior mandible line angle (AB/PM), 5.1°±5.8° for posterior C2 body/anterior mandible line angle (PB/AM) and 5.6°±6.2° for posterior C2 body/ posterior mandible line angle (PB/PM). Overall the measurements obtained were correlative with an appropriate range for the standard deviation. Mean intraclass correlation coefficient were 0.889 for O-C2A, 0.795 for AB/AM, 0.859 for AB/PM, 0.876 for PB/AM, and 0.750 for PB/PM, showing high interobserver reliability for all the radiographic measures. Across the five techniques, 87%–92% of measurements fell within 10° of the median, 76%–83% fell within 7.5°, and 55%–66% within 5°. CONCLUSIONS The mandible-C2 angle offers a reproducible alternative to the validated O-C2A technique for determining appropriate intraoperative occipitocervical alignment, which may be especially useful when preoperative radiographic alignment is unknown, such as occurs with trauma patients, with the goal of decreasing alignment-related complications in the setting of occipitocervical stabilization.

Case Isolated patella absentia is an extremely rare phenomenon, with only a few published cases and even fewer follow-up reports. Nearly 40 years after the initial presentation of 2 brothers with bilateral congenital absence of the patella and the publication of a case report, we report the clinical and radiographic findings of their subsequent tibiofemoral osteoarthritis, which was treated with bilateral total knee arthroplasty. Conclusion Understanding the biomechanical complications associated with congenital absence of the patella as it relates to a stable knee is vital; in the case of degenerative changes, total knee arthroplasty appears to provide a long-term solution for these patients.