Hybrid spinal constructs using sublaminar polyester bands in posterior instrumented fusions in children: a series of 5 cases.

OBJECTIVE: The authors report the novel use of sublaminar polyester bands in posterior instrumented spinal fusions of the thoracic and lumbar spine and sacrum in 5 children. This is the first reported use of polyester bands in spinal surgery in the United States. METHODS: The authors retrospectively reviewed the demographics and procedural data for children who underwent posterior instrumented fusion using sublaminar polyester bands. RESULTS: Five children, ranging in age from 9 months to 18 years, underwent posterior instrumented fusion for posttrauma kyphotic deformity (1 patient), congenital scoliosis from hemivertebra anomaly (3 patients), and neuromuscular scoliosis associated with spina bifida (1 patient). There were 1 instance of lamina fracture with application and tensioning of the polyester band and 1 instance of transient worsening of proprioception with sublaminar passage of the polyester band. CONCLUSION: Pedicle screws, laminar/pedicle/transverse process hooks, and sublaminar metal wires have been incorporated into posterior spinal constructs and widely reported and used in the thoracic and lumbar spine and sacrum with varying success. This report demonstrates the successful results of hybrid posterior spinal constructs that include sublaminar polyester bands that promise the technical ease of passing sublaminar instrumentation with the immediate biomechanical rigidity of pedicle screws and hooks.

Use of axial and subaxial translaminar screw fixation in the management of upper cervical spinal instability in a series of 7 children.

OBJECTIVE: The management of upper cervical spinal instability in children continues to represent a technical challenge. Traditionally, a number of wiring techniques followed by halo orthosis have been applied; however, they have been associated with a high rate of nonunion and poor tolerance for the halo. Alternatively, C1-C2 transarticular screws and C2 pars/pedicle screws allow more rigid fixation, but they are technically demanding and associated with vertebral artery injuries. Recently, C2 translaminar screws have been added to the armamentarium of the pediatric spine surgeon as a technically simple and biomechanically efficient method of fixation. However, subaxial translaminar screws have not been described in the pediatric population. We describe our experience with axial and subaxial translaminar screws in 7 pediatric patients. METHODS: Seven pediatric patients with the diagnosis of upper cervical spinal instability required surgical fixation (age, 19 months-14 years; sex, 4 boys and 3 girls; follow-up, 4-21 months; etiology, trauma [3 patients], os odontoideum/os terminale [2 patients], hypoplastic dens [2 patients]). All patients underwent axial and/or subaxial translaminar screw insertion. Iliac crest bone graft was used for fusion in 4 patients; bone morphogenic protein and cancellous morselized allograft was used for fusion in 3 patients. A rigid cervical collar was applied for 12 weeks postoperatively in all cases. No intraoperative image guidance was used for insertion of the translaminar screws. RESULTS: All patients had a postoperative computed tomographic scan. Two patients underwent placement of bilateral crossing C2 translaminar screws. Two patients had subaxial translaminar screw placement at C3 and the upper thoracic spine, respectively. Hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in 3 patients. No patients were found to have a breach of the ventral laminar cortex. All patients achieved solid fusion. One patient had a perioperative complication: prolonged dysphagia probably related to C1 lateral mass screw insertion rather than C2 translaminar screw placement. CONCLUSION: To our knowledge, this report represents the only series of pediatric patients treated with axial and subaxial translaminar screws. This series shows that axial and subaxial translaminar screw fixation is a viable option for upper cervical spinal fusion in children. The technique is safe and results in adequate fixation with high fusion rates and minimal complications.

Postlaminoplasty kyphotic deformity in the thoracic spine: case report and review of the literature.

In the pediatric population, a strong correlation between multilevel laminectomy and postlaminectomy spinal deformities, predominantly kyphosis, has been demonstrated. This has been observed mainly in the cervical and thoracic spine. Therefore, laminoplasty was proposed as an alternative to laminectomy with a reduced incidence of spinal deformity and need for stabilization and fusion. Moreover, to the best of our knowledge, postlaminoplasty kyphosis of the thoracic spine has not been previously described in the literature. We report the case of a pediatric patient who rapidly developed severe thoracic kyphosis 3 months after resection of a symptomatic extradural spinal arachnoid cyst and multilevel en bloc thoracic laminoplasty, and review the relevant literature.

Periosteal chondroma of the pediatric cervical spine.

Periosteal chondromas located in the spine are rare. The authors document an even more infrequent occurrence of a recurrent periosteal chondroma in the cervical spine of a 6-year-old boy. During the operation, a giant (>7 cm in diameter) periosteal chondroma with involvement of the C-5 and C-6 vertebral bodies was resected. The vertebral column was reconstructed with anterior-posterior instrumentation. The pathological examination revealed that the tumor consisted of chondroid tissue with typical chondrocytes, confirming the diagnosis of periosteal chondroma.

Translaminar screw fixation in the subaxial pediatric cervical spine.

The use of spinal instrumentation to stabilize the occipitocervical junction in pediatric patients has increased and evolved in recent years. Wiring techniques have now given way to screw-rod or screw-plate techniques with or without postoperative external immobilization. Although C-2 translaminar screws have been used in these constructs, subaxial translaminar screws have not, to date, been described in either the pediatric or adult patient populations. The authors describe the feasibility of translaminar screw placement in the C-3 lamina. Rigid fixation with translaminar screws offers an alternative to subaxial fixation with lateral mass screws, allowing for formation of biomechanically sound spinal constructs and minimizing potential neurovascular morbidity. Their use requires careful analysis of preoperative imaging studies, intact posterior elements, and avoidance of violation of the inner laminar wall.

Diagnosing cranial fasciitis based on distinguishing radiological features.

Primary skull lesions, albeit rare in the pediatric population, have been well described and classified. These lesions are usually benign and commonly present as a painless mass. The most common lesions are epidermoid, dermoid, and Langerhans cell histiocytosis. Cranial fasciitis, encountered less frequently, is usually not considered in this differential diagnosis. Given such few cases reported, it is commonly misdiagnosed preoperatively. The authors retrospectively reviewed data obtained in 4 patients with cranial fasciitis in whom the diagnosis was based on histopathological findings. In 2 patients the onset of the lesion was spontaneous. One patient had a lesion 4 months following a vacuum extraction and subsequent cephalohematoma formation. One patient developed a lesion following a previous craniectomy. Presentation, imaging studies, and histopathological findings were all reviewed and analyzed. All patients presented with a firm nontender mass. Radiological features included a lytic bone lesion with a mildly sclerotic margin, T1 isodensity, T2 heterogeneous hyperdensity, and heterogeneous enhancement. The enhancing portion was not bright on T2-weighted MR images, likely representing the fibrous component; the nonenhancing portion was bright on T2-weighted images, likely representing the myxoid matrix. Histopathological examination revealed proliferating fibroblasts in a myxoid matrix. Cranial fasciitis is a benign, painless but rapidly growing lesion of the skull mainly limited to the pediatric population. It is histologically similar to nodular fasciitis, a fibroblastic proliferation of varying size. These lesions are often related to trauma but can also be insidious or can develop at a prior craniectomy site. The appropriate clinical picture and distinguishing radiographic features may help to differentiate cranial fasciitis from other lesions of the skull allowing for earlier intervention.

Corpus callosotomy in children with intractable epilepsy using frameless stereotactic neuronavigation: 12-year experience at the Hospital for Sick Children in Toronto.

OBJECT: Although corpus callosotomy has been used effectively since the late 1930s to treat severe, medically intractable seizure disorders, particularly atonic or drop-attack seizures, controversy remains as to when, how, and how much surgery should be performed. Intraoperative determination of the extent of callosotomy, the need to stage the procedure, and the side of the interhemispheric approach represent technical issues that remain debatable. The authors report the 12-year experience of the senior author as well as surgical outcomes with corpus callosotomy using a frameless stereotactic neuronavigation system (ISG View Wand and BrainLab). METHODS: Thirteen consecutive children at The Hospital for Sick Children underwent single-stage corpus callosotomy for medically intractable seizures. The mean age was 10.3 years. Five children underwent partial callosotomy, and 8 underwent complete callosotomy. The side of operative approach to avoid large parasagittal bridging veins was determined by preoperative study of 3D MR imaging/MR venography reconstructed by the neuronavigation system. The extent of callosotomy was determined using intraoperative feedback from the neuronavigation system and postoperative MR imaging. RESULTS: The extent of callosotomy determined by intraoperative neuronavigation and postoperative MR imaging correlated closely in all cases. There were no operative deaths. There was no significant postoperative morbidity related to venous infarction. Four of 5 patients in the partial callosotomy cohort and 7 of 8 patients in the complete callosotomy cohort showed significant improvement in seizure control. CONCLUSIONS: The use of frameless stereotactic neuronavigation is a safe, effective, and important surgical adjunct in the planning and execution of successful corpus callosotomy in children with intractable epilepsy.