Management of a Complex Basilar Invagination Case with Multiple Revision Surgeries – Case Report

We describe a Basilar Invagination (BI) case with craniocervical instability and many previous failure surgeries and poor wound coverage. The patient had been submitted to a large posterior fossa craniectomy (which greatly limited the availability of an adequate area for bone fixation) and showed a poor quality of the surgical wound in the posterior craniocervical region. We performed an occipito-cervical fixation, using the bone overlying the torculla as a point of cranial fixation. Craniocervical realignment was achieved by the use of distractive maneuvers with occipital rods, followed by coverage of the hardware via a pedicled longitudinal trapeze myocutaneous flap. We used local ribs removed from the region where the myocutaneous flap was harvested as autologous bone grafts for craniocervical fusion. Post-operatively, the patient was placed in a halo-vest for three months. The patient improved substantially after the procedure, recovered some muscular strength and experienced total relief of her pain. We hereby discuss the surgical strategy used for treating this complex case in details, with illustrative pictures.

Biomechanical Evaluation of the Craniovertebral Junction After Anterior Unilateral Condylectomy: Implications for Endoscopic Endonasal Approaches to the Cranial Base

BACKGROUND: Endoscopic endonasal approaches to the craniovertebral junction and clivus, which are increasingly performed for ventral skull base pathology, may require disruption of the occipitocondylar joint. OBJECTIVE: To study the biomechanical implications at the craniovertebral junction of progressive unilateral condylectomy as would be performed through an endonasal exposure. METHODS: Seven upper cervical human cadaveric specimens (C0-C2) underwent nondestructive biomechanical flexibility testing during flexion-extension, axial rotation, and lateral bending at C0-C1 and C1-C2. Each specimen was tested intact, after an inferior one-third clivectomy, and after stepwise unilateral condylectomy with an anterior approach. Angular range of motion (ROM), lax zone, and stiff zone were determined and compared with the intact state. RESULTS: At C0-C1, mobility during flexion-extension and axial rotation increased significantly with progressive condylectomy. ROM increased from 14.3 ± 2.7° to 20.4 ± 5.2° during flexion and from 6.7 ± 3.5° to 10.8 ± 3.0° during right axial rotation after 75% condyle resection (P < .01). At C1-C2, condylectomy had less effect, with ROM increasing from 10.7 ± 2.0° to 11.7 ± 2.0° during flexion, 36.9 ± 4.8° to 37.1 ± 5.1° during right axial rotation, and 4.3 ± 1.9° to 4.8 ± 3.3° during right lateral bending (P = NS). Because of marked instability, the 100% condylectomy condition was untestable. Changes in ROM were a result of changes more in the lax zone than in the stiff zone. CONCLUSION: Lower-third clivectomy and unilateral anterior condylectomy as would be performed in an endonasal approach cause progressive hypermobility at the craniovertebral junction. On the basis of biomechanical criteria, craniocervical fusion is indicated for patients who undergo > 75% anterior condylectomy.

Complex pediatric cervical spine surgery using smaller nonspinal screws and plates and intraoperative computed tomography

Object The treatment of craniocervical instability in children is often challenging due to their small spine bones, complex anatomy, and unique syndromes. The authors discuss their surgical experience with 33 cases in the treatment of 31 children (≤17 years of age) with craniocervical spine instability using smaller nontraditional titanium screws and plates, as well as intraoperative CT. Methods All craniocervical fusion procedures were performed using intraoperative fluoroscopic imaging and electrophysiological monitoring. Nontraditional spine hardware included smaller screw sizes (2.4 and 2.7 mm) from the orthopedic hand/foot set and mandibular plates. Twenty-three of the 33 surgical procedures were performed with intraoperative CT, which was used to confirm adequate position of the spine hardware and alignment of the spine. Results The mean patient age was 9.5 years (range 2–17 years). Eleven children underwent a posterior C1–2 transarticular screw fusion, 17 had an occipitocervical fusion, and 3 had a posterior subaxial cervical fusion. The follow-up duration ranged from 9 to 72 months (mean 53 months). All children demonstrated successful fusion at their 3-month follow-up visit, except 1 patient whose unilateral C1–2 transarticular screw fusion required a repeat surgery before proper fusion was achieved. Of the 47 C1–2 transarticular screws that were placed, 13 were 2.4 mm, 15 were 2.7 mm, 7 were 3.5 mm, and 12 were 4.0 mm. Eighteen of the 47 C1–2 transarticular screws were suboptimally placed. Eleven of these misplaced screws were removed and redirected within the same operation because these surgeries benefitted from the use of intraoperative CT; 6 of the 7 remaining suboptimally placed screws were left in place because a second surgery for screw replacement was not warranted. The other suboptimally placed C1–2 screw was replaced during a repeat operation due to failure of fusion. Use of intraoperative CT was invaluable because it enabled the authors to reposition suboptimal C1–2 transarticular screws without necessitating a second operation. Conclusions Successful craniocervical fusion procedures were achieved using smaller nontraditional titanium screws and plates. Intraoperative CT was a helpful adjunct for confirming and readjusting the trajectory of the screws prior to leaving the operating room, which decreases overall treatment costs and reduces complications.

A Review of Complications Associated With Craniocervical Fusion Surgery

BACKGROUND: Fusion at the craniovertebral junction is performed to treat instability of the upper cervical spine and occiput. The literature consists exclusively of case series in which complication rate and avoidance are variably addressed. OBJECTIVE: To describe the rates of various complications encountered during craniocervical fusions and discuss preoperative and perioperative strategies useful for risk reduction. METHODS: A computerized search of PubMed for literature on craniocervical fusion and other upper cervical fusions was performed. Keywords used in the search included: occipitocervical fusion, odontoid screw, atlantoaxial fusion, with and without complications, anterior fixation, lateral mass screw, transarticular screw, halo, vertebral artery injury, and odontoid fracture. References were limited to studies on human subjects. Other sources were identified from the reference lists of relevant publications. RESULTS: Twenty-two reports described data derived from 2274 procedures analyzed for complications. The most commonly encountered perioperative complications were related to instrumentation failure after nonunion with rates as high as 7% during occipitocervical fusion and 6.7% during atlantoaxial fusion. Other commonly encountered complications included injury to the vertebral artery (1.3%-4.1% during placement of C1-C2 transarticular screws, most commonly in the case of high-riding vertebral artery), dural tears, and wound infection. CONCLUSION: Occipitocervical or atlantoaxial fusion procedures can be performed with low morbidity. Safety is enhanced with appropriate preoperative assessment of anatomic variants and preparation for perioperative management of complications.

Craniocervical Stabilization Using Luque/Hartshill Rectangles

Unteated craniocervical instability is associated with a high morbidity and a significant mortality. Existing methods using bone grafts, interlaminar wires, or acrylic eventually produce stability but require prolonged periods of immobility and have a high failure rate. The ideal method of fixation should provide for permanent correction of deformity and relief of symptoms, with immediate stabilization, at a single procedure. Posterior fixation of the occiput to a stable part of the cervical spine with a molded metal rectangle held in place by interlaminar wires was used to accomplish this. We report 20 patients treated consecutively who have undergone craniocervical fusion by this method using Luque/Hartshill rectangles. Fourteen patients had preexisting atlantoaxial instability and 6 had cord compression, but would become unstable after decompression. All operations were performed under general anesthesia; 9 patients (40%) were awake for intubation/positioning, and 7 patients had a simultaneous decompression. Sixteen patients made an uncomplicated recovery and became mobile 3 days postoperatively. Symptomatic and neurological improvement occurred in 70% of all patients. Neurological complications occurred in 4 patients (20%), reflecting the serious nature of the condition; 2 patients (10%) showed no change. Scrutiny of their presentations and operations failed to identify avoidable risk factors, except faulty wiring techniques. In all patients, permanent stabilization was achieved immediately, facilitating early mobilization with a real chance of improvement, which indicates that the method merits wider application. (Neurosurgery 26:32-36, 1990)