✓ Posterior occipitocervical stabilization procedures were successfully performed in 10 patients (nine boys and one girl) 16 years of age or younger by using C1–2 transarticular screws coupled with a rigid occipitocervical construct. The average length of follow-up evaluation was 18.8 months (range 5–37 months). No implant failed and all fusions were successful without the use of an external orthotic halo device.
Douglas L. Brockmeyer and Ronald I. Apfelbaum
Douglas L. Brockmeyer, Julie E. York and Ronald I. Apfelbaum
Craniovertebral instability is a challenging problem in pediatric spinal surgery. Recently, C1-2 transarticular screw fixation in pediatric patients has been used to assist in the stabilization of the craniovertebral joint. Currently there are no data that define the anatomical suitability of this technique in the pediatric population. The authors report their experience in 32 pediatric patients in whom craniovertebral instability was treated by placement of C1-2 transarticular screws.
From March 1991 to October 1998, 32 patients 16 years of age or younger with atlantooccipital, or atlantoaxial instability, or both were evaluated at our institution. There were 22 boys and 10 girls. Their ages ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (nine patients). Six patients had undergone a total of nine previous attempts at posterior fusion at outside institutions.
All patients underwent extensive preoperative radiological evaluation including thin cut (1-mm) computerized tomography scanning with multiplanar reconstruction to evaluate the C1-2 joint space anatomy. Of the 64 possible C1-2 joint spaces in 32 patients, 55 sides (86%) were considered suitable for transarticular screw placement preoperatively. In three patients the C1-2 joint space anatomy was considered unsuitable for screw placement bilaterally. In three patients the anatomy was considered inadequate on one side. Fifty-five C1-2 transarticular screws were subsequently placed, with no resulting neurological or vascular complications. We conclude that C1-2 transarticular screw fixation is technically possible in a large proportion of pediatric patients with craniovertebral instability.
Douglas L. Brockmeyer, Julie E. York and Ronald I. Apfelbaum
Object. Craniovertebral instability is a challenging problem in pediatric spinal surgery. Recently, C1–2 transarticular screw fixation has been used to assist in craniovertebral joint stabilization in pediatric patients. Currently there are no available data that define the anatomical suitability of this technique in the pediatric population. The authors report their experience in treating 31 pediatric patients with craniovertebral instability by using C1–2 transarticular screws.
Methods. From March 1992 to October 1998, 31 patients who were 16 years of age or younger with atlantooccipital or atlantoaxial instability, or both, were evaluated at our institution. There were 21 boys and 10 girls. Their ages ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (eight patients). Six patients had undergone a total of nine previous attempts at posterior fusion while at outside institutions.
All patients underwent extensive preoperative radiological evaluation including fine-slice (1-mm) computerized tomography scanning with multiplanar reconstruction to evaluate the anatomy of the C1–2 joint space. Preoperatively, of the 62 possible C1–2 joint spaces in 31 patients, 55 sides (89%) were considered suitable for transarticular screw placement. In three patients the anatomy was considered unsuitable for bilateral screw placement. In three patients the anatomy was considered inadequate on one side. Fifty-five C1–2 transarticular screws were subsequently placed, and there were no neurological or vascular complications.
Conclusions. The authors conclude that C1–2 transarticular screw fixation is technically possible in a large proportion of pediatric patients with craniovertebral instability.
Douglas L. Brockmeyer
✓ A new technique for performing a posterior rib and multistranded cable atlantoaxial fusion in children is described. The technique has been used successfully, in two patients 22 and 18 months of age, respectively. In both cases, fusion was used to augment C1–2 transarticular screw fixation, and solid arthrodesis was achieved without a halo orthosis.
James K. Liu, Douglas L. Brockmeyer, Andrew T. Dailey and Meic H. Schmidt
Aneurysmal bone cysts of the spine are benign, highly vascular osseous lesions of unknown origin that may present difficult diagnostic and therapeutic challenges. They are expansile lesions containing thin-walled, blood-filled cystic cavities that cause bone destruction and sometimes spinal deformity and neurological compromise. The treatment of aneurysmal bone cysts of the spine remains controversial according to the literature. In this review, the authors discuss the clinical manifestations, pathophysiological features, neuroimaging characteristics, and treatment strategies for these lesions.
Treatment options include simple curettage with bone grafting, complete excision, embolization, and radiation therapy. Reconstruction and stabilization of the spine may be warranted if deformity and instability are present. Special factors need to be considered in the management of these lesions.
Complete excision of aneurysmal bone cysts offers the best chance of cure and spinal decompression if neurological deficits are present.
Richard C. E. Anderson, Peter Kan, Paul Klimo, Douglas L. Brockmeyer, Marion L. Walker and John R. W. Kestle
Object. Intracranial pressure (ICP) monitoring has become routine in the management of patients with traumatic brain injury (TBI). Many surgeons prefer to use external ventricular drains (EVDs) over fiberoptic monitors to measure ICP because of the added benefit of cerebrospinal fluid drainage. The purpose of this study was to examine a consecutive series of children with TBI and compare the incidence of complications after placement of an EVD, a fiberoptic intraparencyhmal monitor, or both.
Methods. A retrospective chart review was conducted to identify children with TBI who met the criteria for insertion of an ICP monitor. All patients underwent head CT scanning on admission and after placement of an ICP monitor.
During a 5-year period 80 children met the criteria for inclusion in the study. Eighteen children (22.5%) underwent EVD placement only, 18 (22.5%) underwent placement of a fiberoptic device only, and 44 (55%) received both. A total of 62 fiberoptic devices (48%) were inserted, and 68 EVDs (52%) were placed. Overall, there was a fourfold increased risk of complications in children who received an EVD compared with those in whom a fiberoptic monitor was placed (p = 0.004). Hemorrhagic complications were detected in 12 (17.6%) of 62 patients who received an EVD compared with four (6.5%) of 62 patients who received a fiberoptic monitor (p = 0.025). Six (8.8%) of 68 EVDs were malpositioned and required replacement; in three (50%) of these cases a hemorrhagic complication occurred. Only one infection was noted in a patient with an EVD (1.5%).
Conclusions. In this retrospective cohort of pediatric patients with TBI, complication rates were significantly higher in those receiving EVDs than in those in whom fiberoptic monitors were placed. Although the majority of these complications did not entail clinical sequelae, surgeons should be aware of the different complication rates when choosing the most appropriate device for each patient.
John Kestle, Jeannette J. Townsend, Douglas L. Brockmeyer and Marion L. Walker
Object. In reports involving the operative treatment of brainstem tumors, multiple histological types are often grouped together. To determine prognosis after resection, histology-specific data may be helpful.
Methods. Twenty-eight patients with juvenile pilocytic astrocytoma (JPA) of the brainstem (six in the midbrain, four in the pons, and 18 in the medulla) were identified from the medical records. Initial treatment was resection in 25 and biopsy sampling in three. Postoperative imaging revealed gross-total resection (GTR) or resection with linear enhancement (RLE) in 12 of 25 patients and solid residual tumor in the other 13.
In 10 of the 13 patients harboring solid residual tumor, observation was undertaken; the residual lesion disappeared in one, was stable in four, and progressed in five. Of the 12 patients with complete excision or RLE only, seven underwent no further treatment, with tumor progression occurring in one. All patients were alive at last follow-up examination (range 0.3–20.4 years, mean 6 years). New neurological deficits commonly appeared immediately after resection but often resolved. In six of the 28 patients, the new postoperative deficit was still present at last follow-up visit. The 5- and 10-year progression-free survival was 74 and 62%, respectively, after GTR or RLE and 19 and 19%, respectively, when solid residual tumor was present.
Conclusions. Long-term survival after resection of JPAs of the brainstem has been observed and appears to be related to the extent of initial excision.
Wayne M. Gluf and Douglas L. Brockmeyer
Object. In this, the second of two articles regarding C1–2 transarticular screw fixation, the authors discuss their surgical experience in treating patients 16 years of age and younger, detailing the rate of fusion, complication avoidance, and lessons learned in the pediatric population.
Methods. The authors retrospectively reviewed 67 consecutive patients (23 girls and 44 boys) younger than 16 years of age in whom at least one C1–2 transarticular screw fixation procedure was performed. A total of 127 transarticular screws were placed in these 67 patients whose mean age at time of surgery was 9 years (range 1.7–16 years). The indications for surgery were trauma in 24 patients, os odontoideum in 22 patients, and congenital anomaly in 17 patients. Forty-four patients underwent atlantoaxial fusion and 23 patients underwent occipitocervical fusion. Two of the 67 patients underwent halo therapy postoperatively.
All patients were followed for a minimum of 3 months. In all 67 patients successful fusion was achieved.Complications occurred in seven patients (10.4%), including two vertebral artery injuries.
Conclusions. The use of C1–2 transarticular screw fixation, combined with appropriate atlantoaxial and craniovertebral bone/graft constructs, resulted in a 100% fusion rate in a large consecutive series of pediatric patients. The risks of C1–2 transarticular screw fixation can be minimized in this population by undertaking careful patient selection and meticulous preoperative planning.
Report of two cases and review of the literature
Ganesh Rao, Richard C. E. Anderson, Neil A. Feldstein and Douglas L. Brockmeyer
✓Arachnoid cysts are intracranial, space-occupying lesions that typically remain stable in size on serial imaging. The authors describe two cases of rapidly enlarging arachnoid cysts, including one located in the anterior fossa.
In the first case a 7-month-old boy presented with increasing head circumference and a rapidly enlarging arachnoid cyst in the left middle fossa, which had been documented by serial imaging over the preceding 6 months. In the second case a 4-year-old girl presented with an arachnoid cyst compressing the right frontal lobe. The cyst had not been present on imaging studies performed during the perinatal period. In both cases, a craniotomy for open fenestration of the cyst was performed with successful resolution of the mass effect.
Rare cases of expansion of arachnoid cysts have been reported in the literature. In this article the authors report the dramatic enlargement of two arachnoid cysts, including the first description of enlargement of an arachnoid cyst located in the anterior fossa.