Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Keyne K. Johnson x
  • Refine by Access: all x
Clear All Modify Search
Restricted access

Translaminar screw fixation in the subaxial pediatric cervical spine

Technical note

Andrew Jea, Keyne K. Johnson, William E. Whitehead, and Thomas G. Luerssen

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.

Restricted access

Periosteal chondroma of the pediatric cervical spine

Case report

Daniel K. Fahim, Keyne K. Johnson, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea

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.

Restricted access

Routine imaging in patients with ventriculopleural shunts: lessons learned from a case of tension hydrothorax

Case illustration

Benjamin D. Fox, Vikram V. Nayar, Keyne K. Johnson, Andrew Jea, Daniel Curry, Thomas G. Luerssen, and William E. Whitehead

Full access

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

Andrew Jea, Shobhan Vachhrajani, Keyne K. Johnson, and James T. Rutka


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).


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.


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.


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.

Restricted access

Diagnosing cranial fasciitis based on distinguishing radiological features

Report of 4 cases

Keyne K. Johnson, Mark J. Dannenbaum, Meenakshi B. Bhattacharjee, Anna Illner, Robert C. Dauser, William E. Whitehead, Andrew Jea, and Thomas G. Luerssen

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.