Tag: Craniocervical instability

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Spinal navigation for posterior instrumentation of C1–2 instability using a mobile intraoperative CT scanner

J Neurosurg Spine 27:268–275, 2017

Spinal navigation techniques for surgical fixation of unstable C1–2 pathologies are challenged by complex osseous and neurovascular anatomy, instability of the pathology, and unreliable preoperative registration techniques. An intraoperative CT scanner with autoregistration of C-1 and C-2 promises sufficient accuracy of spinal navigation without the need for further registration procedures. The aim of this study was to analyze the accuracy and reliability of posterior C1–2 fixation using intraoperative mobile CT scanner–guided navigation.

METHODS In the period from July 2014 to February 2016, 10 consecutive patients with instability of C1–2 underwent posterior fixation using C-2 pedicle screws and C-1 lateral mass screws, and 2 patients underwent posterior fixation from C-1 to C-3. Spinal navigation was performed using intraoperative mobile CT. Following navigated screw insertion in C-1 and C-2, intraoperative CT was repeated to check for the accuracy of screw placement. In this study, the accuracy of screw positioning was retrospectively analyzed and graded by an independent observer.

RESULTS The authors retrospectively analyzed the records of 10 females and 2 males, with a mean age of 80.7 ± 4.95 years (range 42–90 years). Unstable pathologies, which were verified by fracture dislocation or by flexion/extension radiographs, included 8 Anderson Type II fractures, 1 unstable Anderson Type III fracture, 1 hangman fracture Levine Effendi Ia, 1 complex hangman-Anderson Type III fracture, and 1 destructive rheumatoid arthritis of C1–2. In 4 patients, critical anatomy was observed: high-riding vertebral artery (3 patients) and arthritis-induced partial osseous destruction of the C-1 lateral mass (1 patient). A total of 48 navigated screws were placed. Correct screw positioning was observed in 47 screws (97.9%). Minor pedicle breach was observed in 1 screw (2.1%). No screw displacement occurred (accuracy rate 97.9%).

CONCLUSION Spinal navigation using intraoperative mobile CT scanning was reliable and safe for posterior fixation in unstable C1–2 pathologies with high accuracy in this patient series.

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Craniocervical Instability in the Setting of Os Odontoideum

Craniocervical Instability in the Setting of Os Odontoideum

Neurosurgery 76:514–521, 2015

Our clinical understanding of os odontoideum (OO) remains incomplete. Congenital and traumatic causes have been proposed and advocated. Clinical presentations range from asymptomatic to axial pain to myelopathy or vertebral-basilar ischemia. A consensus for surgical management exists for those found to have an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression.

OBJECTIVE: To evaluate the clinical presentation and surgical outcomes of patients with OO and an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression.

METHODS: Patients with a diagnosis of OO who underwent surgical management were included. Patients were excluded on the basis of previous C2 fracture, Fielding diagnostic criteria, and inadequate follow-up. History of trauma and presenting symptoms were assessed. Clinical and neurological improvements were measured with the use of patient satisfaction scores and the Japanese Orthopaedic Association scores. Fusion status was documented with the use of radiographs and computed tomographic imaging.

RESULTS: Of 279 patients, 112 reported a history of cranial-vertebral junction trauma, whereas 28 were diagnosed with congenital malformations. Clinically, 84.9% of patients presented with myelopathy, with pain presented in 42.6%. Atlantoaxial fixation was performed in 240 patients, occiput-to-C2 fixation in 35 patients, and extended occipitocervical fixation in 4 patients. Mean follow-up was 40.3 months. Complications were reported in 2.4% of patients. Japanese Orthopaedic Association scores improved from a preoperative mean of 12.4 to 14.8. Two hundred thirty-five patients (77.7%) improved, with 30 patients experiencing no change in symptoms and 14 patients deteriorating. Fusion was achieved in 96.8% of patients.

CONCLUSION: Our data reveal that surgical treatment for OO using the indications and techniques delineated is associated with high satisfaction rates, improved functional scores, and high fusion rates with low complication rates.

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