Lee A. Tan and Peter D. Angevine
Brian J. Kelley, Anas A. Minkara, Peter D. Angevine, Michael G. Vitale, Lawrence G. Lenke and Richard C. E. Anderson
The long-term effects of instrumentation and fusion of the occipital-cervical-thoracic spine on spinal growth in young children are poorly understood. To mitigate the effects of this surgery on the growing pediatric spine, the authors report a novel technique used in 4 children with severe cervical-thoracic instability. These patients underwent instrumentation from the occiput to the upper thoracic region for stabilization, but without bone graft at the craniovertebral junction (CVJ). Subsequent surgery was then performed to remove the occipital instrumentation, thereby allowing further growth and increased motion across the CVJ.
Three very young children (15, 30, and 30 months old) underwent occipital to thoracic posterior segmental instrumentation due to cervical or upper thoracic dislocation, progressive kyphosis, and myelopathy. The fourth child (10 years old) underwent similar instrumentation for progressive cervical-thoracic scoliosis. Bone graft was placed at and distal to C-2 only. After follow-up CT scans demonstrated posterior arthrodesis without unintended fusion from the occiput to C-2, 3 patients underwent removal of the occipital instrumentation.
Follow-up cervical spine flexion/extension radiographs demonstrated partial restoration of motion at the CVJ. One patient has not had the occipital instrumentation removed yet, because only 4 months have elapsed since her operation.
Temporary fixation to the occiput provides increased biomechanical stability for spinal stabilization in young children, without permanently eliminating motion and growth at the CVJ. This technique can be considered in children who require longer instrumentation constructs for temporary stabilization, but who only need fusion in more limited areas where spinal instability exists.
Peter D. Angevine and Paul C. McCormick
Peter D. Angevine and Paul C. McCormick
The routine practice of neurosurgery generates a large amount of clinical data. The structured, systematic capture of this information using clinical registries or other rigorously designed observational studies can yield useful evidence to help improve the care of patients. Registries in particular can be designed to measure outcomes in real-world clinical settings and to study differences in outcomes between subgroups. This information can help clinicians to advise patients regarding their treatment options.
To provide valid, generalizable evidence, however, registries and other observational studies must be designed and conducted with a rigor similar to that of randomized clinical trials. Neurosurgeons with a basic understanding of the potential advantages and pitfalls of nonrandomized trials and the methods of statistical analysis will be able to assess the quality of clinical data and to incorporate the findings appropriately into their patients' care.
Peter D. Angevine and Paul C. McCormick
Kyle M. Fargen, Richard C. E. Anderson, David H. Harter, Peter D. Angevine, Valerie C. Coon, Douglas L. Brockmeyer and David W. Pincus
Although rarely encountered, pediatric patients with severe cervical spine deformities and instability may occasionally require occipitocervicothoracic instrumentation and fusion. This case series reports the experience of 4 pediatric centers in managing this condition. Occipitocervical fixation is the treatment of choice for craniocervical instability that is symptomatic or threatens neurological function. In children, the most common distal fixation level with modern techniques is C-2. Treated patients maintain a significant amount of neck motion due to the flexibility of the subaxial cervical spine. Distal fixation to the thoracic spine has been reported in adult case series. This procedure is to be avoided due to the morbidity of complete loss of head and neck motion. Unfortunately, in rare cases, the pathological condition or highly aberrant anatomy may require occipitocervical constructs to include the thoracic spine.
The authors identified 13 patients who underwent occipitocervicothoracic fixation. Demographic, radiological, and clinical data were gathered through retrospective review of patient records from 4 institutions.
Patients ranged from 1 to 14 years of age. There were 7 girls and 6 boys. Diagnoses included Klippel-Feil, Larsen, Morquio, and VATER syndromes as well as postlaminectomy kyphosis and severe skeletal dysplasia. Four patients were neurologically intact and 9 had myelopathy. Five children were treated with preoperative traction prior to instrumentation; 5 underwent both anterior and posterior spinal reconstruction. Two patients underwent instrumentation beyond the thoracic spine. Allograft was used anteriorly, and autologous rib grafts were used in the majority for posterior arthrodesis. Follow-up ranged from 0 to 43 months. Computed tomography confirmed fusion in 9 patients; the remaining patients were lost to follow-up or had not undergone repeat imaging at the time of writing. Patients with myelopathy either improved or stabilized. One child had mild postoperative unilateral upper-extremity weakness, and a second child died due to a tracheostomy infection. All patients had severe movement restriction as expected.
Occipitocervicothoracic stabilization may be employed to stabilize and reconstruct complex pediatric spinal deformities. Neurological function can be maintained or improved. The long-term morbidity of loss of cervical motion remains to be elucidated.
Peter D. Angevine, Christopher Kellner, Raqeeb M. Haque and Paul C. McCormick
Access to the ventral intradural spinal canal may be required for treatment of a variety of lesions affecting the spinal cord and adjacent intradural structures. Adequate exposure is usually achieved through a standard posterior laminectomy or posterolateral approaches, although formal anterior approaches are used to access lesions in the subaxial cervical spine. Modifications of the standard posterior exposure as well as ventral or ventrolateral approaches are increasingly being used for treating intradural spinal pathologies. In this study, the authors review their experience with 35 consecutive cases of ventral intradural spinal lesions.
Only patients with intradural lesions located completely ventral to the dentate ligament attachments were included in this retrospective study. Patients with the following lesions were excluded from the study: lesions at the level of the filum terminale/cauda equina, lesions with any component that extended dorsally to the dentate ligament, or lesions with extradural extension (that is, dumbbell tumors) below the C-2 level. Between January 2000 and September 2009, a total of 35 patients (age range 17–72 years, mean 42.6 years) with ventral intradural spinal pathology underwent surgery at the authors' institution.
There were 28 intradural extramedullary mass lesions: 15 meningiomas, 12 solitary schwannomas, and 1 neuroenteric cyst. Surgical approaches to these lesions included 23 posterior or posterolateral approaches, 4 anterior approaches with corpectomy followed by tumor resection and reconstruction, and 1 lateral transforaminal resection. No patient had evidence of instability at follow-up, which ranged from 6 months to 8 years in duration. One patient had worsened spinal cord function following surgery. There were 7 patients with intramedullary lesions: 2 hemangioblastomas, 2 cavernous malformations, 2 perimedullary fistulas, and 1 astrocytoma. All but 1 were superficial pia-based lesions arising ventral to the dentate ligament. Five of the 6 pia-based lesions were successfully resected via a standard posterior laminectomy, partial facetectomy with dentate section, and spinal cord rotation. One midline pial lesion was successfully removed with a minimally invasive retropleural thoracotomy. The astrocytoma was resected through an anterior cervical corpectomy, which was followed by instrumented reconstruction. There were no significant complications or neurological morbidity at follow-up (range 9 months–6 years).
Most intradural spinal lesions can be treated with contemporary microsurgical techniques with long-term control or cure of the lesion and preservation of neurological function. Standard posterior approaches provide adequate exposure to safely remove the vast majority of these lesions without the need for a potentially destabilizing resection of the facet or pedicle. Posterior exposures with varying degrees of lateral bone resection, dentate ligament division, and gentle cord rotation may also provide adequate exposure for safe removal of nonmidline ventrolateral superficial pial presenting spinal cord lesions. Nevertheless, in certain cases of ventral intradural lesions, anterior approaches are necessary and should be considered under appropriate circumstances.