Douglas L. Brockmeyer

Phase II clinical trial of moderate hypothermia after severe traumatic brain injury in children

OBJECTIVE:To determine whether moderate hypothermia (HYPO) (32–33°C) begun in the early period after severe traumatic brain injury (TBI) and maintained for 48 hours is safe compared with normothermia (NORM) (36.5–37.5°C). METHODS:After severe (Glasgow Coma Scale score ≤8) nonpenetrating TBI, 48 children less than 13 years of age admitted within 6 hours of injury were randomized after stratification by age to moderate HYPO (32–33°C) treatment in conjunction with standardized head injury management versus NORM in a multicenter trial. An additional 27 patients were entered into a parallel single-institution trial of excluded patients because of late transfer or consent (delayed in transfer >6 h but within 24 h of admission), unknown time of injury (e.g., child abuse), and adolescence (e.g., aged 13–18 yr). Assessments of safety included mortality, infection, coagulopathy, arrhythmias, and hemorrhage as well as ability to maintain target temperature, mean intracranial pressure (ICP), and percent time of ICP less than 20 mm Hg during the cooling and subsequent rewarming phases. Additionally, assessments of neurocognitive outcomes were obtained at 3 and 6 months of follow-up. RESULTS:Moderate HYPO after severe TBI in children was found to be safe relative to standard management and NORM in children of all ages and in children with delay of initiation of treatment up to 24 hours. Although there was decreased mortality in HYPO in both studies, there was an increased potential for arrhythmias with HYPO, although they were manageable with fluid administration or rewarming. Additionally, there was a reduction in mean ICP during the first 72 hours after injury in both studies, although rebound ICP elevations in HYPO compared with those in NORM were noted for up to 10 to 12 hours after rewarming. Although functional outcome at 3 or 6 months did not differ between treatment groups, functional outcome tended to improve from the 3- to 6-month cognitive assessment in HYPO compared with NORM, although the sample size was too small for any definitive conclusions. CONCLUSION:HYPO is likely a safe therapeutic intervention for children after severe TBI up to 24 hours after injury. Further studies are necessary and warranted to determine its effect on functional outcome and intracranial hypertension.

Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 191 adult patients

OBJECT In this, the first of two articles regarding C1-2 transarticular screw fixation, the authors assessed the rate of fusion, surgery-related complications, and lessons learned after C1-2 transarticular screw fixation in an adult patient series. METHODS The authors retrospectively reviewed 191 consecutive patients (107 women and 84 men; mean age 49.7 years, range 17-90 years) in whom at least one C1-2 transarticular screw was placed. Overall 353 transarticular screws were placed for trauma (85 patients), rheumatoid arthritis (63 patients), congenital anomaly (26 patients), os odontoideum (four patients), neoplasm (eight patients), and chronic cervical instability (five patients). Among these, 67 transarticular screws were placed in 36 patients as part of an occipitocervical construct. Seventeen patients had undergone 24 posterior C1-2 fusion attempts prior to referral. The mean follow-up period was 15.2 months (range 0.1-106.3 months). Fusion was achieved in 98% of cases followed to commencement of fusion or for at least 24 months. The mean duration until fusion was 9.5 months (range 3-48 months). Complications occurred in 32 patients. Most were minor; however, five patients suffered vertebral artery (VA) injury. One bilateral VA injury resulted in patient death. The others did not result in any permanent neurological sequelae. CONCLUSIONS Based on this series, the authors have learned important lessons that can improve outcomes and safety. These include techniques to improve screw-related patient positioning, development of optimal instrumentation, improved screw materials and design, and defining the role for stereotactic navigation. Atlantoaxial transarticular screw fixation is highly effective in achieving fusion, and the complication rate is low when performed by properly trained surgeons.

Endoscopic Third Ventriculostomy: An Outcome Analysis

Endoscopic third ventriculostomy (ETV) has gained widespread acceptance as an effective way to manage hydrocephalus in selected patients. To determine which patient groups have the highest chance of successful ETV, a retrospective case review was performed. From June 1992 to December 1996, 97 patients underwent a total of 98 ETVs at our institution. There were 59 males and 38 females with a mean age of 8.1 years (range 1 day to 29.5 years). Twenty-six of 98 procedures (26%) were abandoned due to either unfavorable anatomy, inability to perform a cisternostomy, or hemorrhage. Follow-up data was available in 92 patients for a mean of 24.2 months. The rate of successful ETV in 71 patients, with either complete shunt avoidance or removal, varied widely by diagnosis and patient age. The highest success rates were achieved in patients with aqueductal stenosis, tectal plate tumor, myelomeningocele and posterior fossa tumor. Complications included one transient herniation syndrome, one basilar artery perforation, 2 cases of ventriculitis, one transient decrease in level of consciousness, and one transient hemiparesis. We feel these results support the continued use of ETV in only carefully selected patients with hydrocephalus.

Optic pathway gliomas: a review

Optic pathway gliomas represent approximately 3-5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11-30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5-7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve.

Building consensus: development of a Best Practice Guideline (BPG) for surgical site infection (SSI) prevention in high-risk pediatric spine surgery.

Background: Perioperative surgical site infection (SSI) after pediatric spine fusion is a recognized complication with rates between 0.5% and 1.6% in adolescent idiopathic scoliosis and up to 22% in “high risk” patients. Significant variation in the approach to infection prophylaxis has been well documented. The purpose of this initiative is to develop a consensus-based “Best Practice” Guideline (BPG), informed by both the available evidence in the literature and expert opinion, for high-risk pediatric patients undergoing spine fusion. For the purpose of this effort, high risk was defined as anything other than a primary fusion in a patient with idiopathic scoliosis without significant comorbidities. The ultimate goal of this initiative is to decrease the wide variability in SSI prevention strategies in this area, ultimately leading to improved patient outcomes and reduced health care costs. Methods: An expert panel composed of 20 pediatric spine surgeons and 3 infectious disease specialists from North America, selected for their extensive experience in the field of pediatric spine surgery, was developed. Using the Delphi process and iterative rounds using a nominal group technique, participants in this panel were as follows: (1) surveyed for current practices; (2) presented with a detailed systematic review of the relevant literature; (3) given the opportunity to voice opinion collectively; and (4) asked to vote regarding preferences privately. Round 1 was conducted using an electronic survey. Initial results were compiled and discussed face-to-face. Round 2 was conducted using the Audience Response System, allowing participants to vote for (strongly support or support) or against inclusion of each intervention. Agreement >80% was considered consensus. Interventions without consensus were discussed and revised, if feasible. Repeat voting for consensus was performed. Results: Consensus was reached to support 14 SSI prevention strategies and all participants agreed to implement the BPG in their practices. All agreed to participate in further studies assessing implementation and effectiveness of the BPG. The final consensus driven BPG for high-risk pediatric spine surgery patients includes: (1) patients should have a chlorhexidine skin wash the night before surgery; (2) patients should have preoperative urine cultures obtained; (3) patients should receive a preoperative Patient Education Sheet; (4) patients should have a preoperative nutritional assessment; (5) if removing hair, clipping is preferred to shaving; (6) patients should receive perioperative intravenous cefazolin; (7) patients should receive perioperative intravenous prophylaxis for gram-negative bacilli; (8) adherence to perioperative antimicrobial regimens should be monitored; (9) operating room access should be limited during scoliosis surgery (whenever practical); (10) UV lights need NOT be used in the operating room; (11) patients should have intraoperative wound irrigation; (12) vancomycin powder should be used in the bone graft and/or the surgical site; (13) impervious dressings are preferred postoperatively; (14) postoperative dressing changes should be minimized before discharge to the extent possible. Conclusions: In conclusion, we present a consensus-based BPG consisting of 14 recommendations for the prevention of SSIs after spine surgery in high-risk pediatric patients. This can serve as a tool to reduce the variability in practice in this area and help guide research priorities in the future. Pending such data, it is the unsubstantiated opinion of the authors of the current paper that adherence to recommendations in the BPG will not only decrease variability in practice but also result in fewer SSI in high-risk children undergoing spinal fusion. Level of Evidence: Not applicable.

Neurenteric cysts of the posterior fossa: recognition, management, and embryogenesis.

Neurenteric cysts are endothelium-lined structures most commonly encountered in the lower cervical or upper thoracic spinal cord. The occurrence of neurenteric cysts within the cranial vault is unusual. We present three patients with neurenteric cysts located within the posterior fossa: one near the jugular foramen deforming the 4th ventricle, a second in the cerebellopontine angle, and a third in the prepontine cistern. Several different theories have been advanced to explain the embryogenesis of neurenteric cysts. We review these theories and conclude that cranial neurenteric cysts may arise from a disturbance of early gastrulation, shortly after the onset of primitive streak regression.

Selection of a rigid internal fixation construct for stabilization at the craniovertebral junction in pediatric patients

OBJECT Atlantoaxial and occipitocervical instability in children have traditionally been treated with posterior bone and wire fusion and external halo orthoses. Recently, successful outcomes have been achieved using rigid internal fixation, particularly C1-2 transarticular screws. The authors describe flow diagrams created to help clinicians determine which method of internal fixation to use in complex anatomical circumstances when bilateral transarticular screw placement is not possible. METHODS The records of children who underwent either atlantoaxial or occipitocervical fixation with rigid internal fixation over an 11-year period were retrospectively reviewed to define flow diagrams used to determine treatment protocols. RESULTS Among the 95 patients identified who underwent atlantoaxial or occipitocervical fixation, the craniocervical anatomy in 25 patients (six atlantoaxial and 19 occipitocervical fixations [26%]) required alternative methods of internal fixation. Types of screw fixation included loop or rod constructs anchored by combinations of C1-2 transarticular screws (15 constructs), C-1 lateral mass screws (11), C-2 pars screws (24), C-2 translaminar screws (one), and subaxial lateral mass screws (six). The mean age of the patients (15 boys and 10 girls) was 9.8 years (range 1.3-17 years). All 22 patients with greater than 3-month follow-up duration achieved solid bone fusion and maintained stable constructs on radiographic studies. Clinical improvement was seen in all patients who had preoperative symptoms. CONCLUSIONS Novel flow diagrams are suggested to help guide selection of rigid internal fixation constructs when performing pediatric C1-2 and occipitocervical stabilizations. Use of these flow diagrams has led to successful fusion in 25 pediatric patients with difficult anatomy requiring less common constructs.

Os odontoideum: presentation, diagnosis, and treatment in a series of 78 patients

OBJECT The most contentious issue in the management of os odontoideum surrounds the decision to attempt atlantoaxial fusion in patients with asymptomatic lesions. The authors examined the clinical presentation and outcome in patients with os odontoideum who underwent surgical stabilization, with an emphasis on 3 patients who initially received conservative treatment and suffered delayed neurological injury. METHODS Seventy-eight patients (mean age 20.5 years; median 15 years) were identified in a 17-year retrospective review. The median follow-up period was 14 months (range 1-115 months). Neck pain was the most common symptom (64%), and 56% of patients presented after traumatic injury. Eighteen patients had neurological signs or symptoms at presentation, and an additional 15 had a history of intermittent or prior neurological symptoms. Fifteen patients had undergone > or = 1 attempt at atlantoaxial fusion elsewhere. RESULTS Seventy-seven patients underwent posterior fusion and rigid screw fixation combined with a graft/wire construct: 75 had C1-2 fusion and 2 had occipitocervical fusion. One patient had an odontoid screw placed. Fusion was achieved in all patients at a median of 4.8 months (range 2-17 months). Approximately 90% of patients had resolution or improvement of their neck pain or neurological symptoms. CONCLUSIONS The authors believe that patients with os odontoideum are at risk for future spinal cord compromise. Forty-four percent of our patients had myelopathic symptoms at referral, and 3 had significant neurological deterioration when a known os odontoideum was left untreated. This risk of late neurological deterioration should be considered when counseling patients. Stabilization using internal screw fixation techniques resulted in 100% fusion, whereas 15% of patients had previously undergone unsuccessful wire and external bracing attempts.

Pediatric cervical spine instrumentation using screw fixation

From July 1986 to August 1993 we performed 24 pediatric cervical spine screw fixation procedures on 23 patients 16 years of age or less. The types of cervical instrumentation procedures performed were as follows: anterior cervical plates 12, posterior C1-2 screw fixations 8, posterior lateral mass plates 2, odontoid screw fixations 2. The mean age of all patients was 14.2 years (range 6-16). Indications for operation included traumatic instability in 20 cases, congenital instability in 1 case, 2 cases of postoperative swan neck deformity, and one reoperation for early graft and hardware failure. Six of the 23 patients had persistent instability following previous failed fusions (3 with 1 prior surgery, 2 with 2 prior surgeries, and 1 with 3 prior surgeries). Eight patients had improvement of their neurological status following operation and 15 remained at their preoperative level of neurological function. No patient was worse neurologically after their procedure. There were no long-term instrumentation, graft or fusion failures. Two complications occurred. One was the aforementioned graft and hardware failure requiring reoperation, the other was a superficial wound infection treated successfully with antibiotics. We feel that cervical spine fixation techniques have increased our ability to stabilize the pediatric cervical spine and have proven to be safe and effective.

Scoliosis Associated with Chiari I Malformations: The Effect of Suboccipital Decompression on Scoliosis Curve Progression. A Preliminary Study

Study Design. A retrospective review of the effect of suboccipital decompression and duraplasty on curve progression in 22 patients who presented with scoliosis, syringomyelia, and a Chiari 1 malformation. Objectives. To document the clinical characteristics of scoliosis in association with a Chiari 1 malformation, determine the effects of suboccipital decompression and duraplasty on scoliosis curve progression over time, and identify the clinical factors (age, gender, and curve characteristics) that may be associated with a clinical improvement in the scoliotic deformity after suboccipital decompression. Summary of Background Data. Prior publications have documented the clinical characteristics, signs, and symptoms of the Chiari 1 malformation. An association between Chiari 1 malformations, syringomyelia, and scoliosis has been recognized and reported. Several authors have also reported on the response of the scoliotic curve to Chiari 1 decompression, but the number of patients in these reports has been small. This cohort represents the largest number of patients to date (21) with Chiari 1 malformations, syringomyelia, and scoliosis who have been treated and followed over time in order to determine the effect of decompression on curve progression. Methods. A retrospective case review of 85 patients, age 16 years or less, who underwent posterior fossa decompression for a Chiari 1 malformation between 1990 and November 2000. A subset of 7 males and 15 females (22 of 85 total patients) who initially presented with scoliosis and were then found to have a Chiari 1 malformation was selected from this larger cohort for further review. The orthopedic and neurosurgical charts, spinal radiographs, and magnetic resonance imaging scans were then reviewed for each of these patients. Results. Twenty-one of the 22 patients who presented with scoliosis met the inclusion criteria of having a Chiari 1 malformation, scoliosis, and an unfused spine during the follow-up period after suboccipital decompression. One patient had a posterior spinal fusion before suboccipital decompression and was excluded from further review. Conclusions. Thirteen patients of the 21 study patients (62%) had curve improvement or stabilization during the follow-up period. Eight of 21 patients (38%) had curve progression. Closer analysis reveals that the age, gender, and initial size of the scoliotic curve influenced the results of suboccipital decompression on the behavior of the scoliosis. Specifically, 10 of 11 patients (91%) who were less than 10 years of age at the time of suboccipital decompression have had their curves improve or stay the same during follow-up. In contrast, 5 of 7 female patients (72%) older than 10 years old with a curve greater than 40° before suboccipital decompression have either been fused or are awaiting fusion.