✓ Regional cerebral blood flow (rCBF) studies were performed during the postoperative period on 16 patients with internal carotid occlusions and inaccessible stenoses, and middle cerebral artery occlusion and stenoses, who underwent superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses. The intra-arterial xenon method with selective application of the xenon bolus through the internal carotid and the newly established superficial temporal channel has allowed comparison of the flow provided by the pathological input with flow through the new input. The results show that initial rCBF (rCBF1) was globally reduced in all patients to a mean of 28.4 ± 11.9 ml/100 gm/min at a mean pCO2 of 29.6 ± 9.55 mm Hg. Patients with transient ischemic attacks (TIA) and minor strokes with minimal residua (RIND) had a mean rCBF1 of 30.4 ± 11.6 ml/100 gm/min at a mean pCO2 of 30 ± 10 mm Hg, while patients with completed strokes had a mean rCBF1 of 25.0 ± 12.4 ml/100 gm/min at a mean pCO2 of 29.1 ± 8.8 mm Hg. There was no significant difference between these two groups. This finding suggests that in this small group of patients with TIA's and RIND's, the cause of the stroke is probably related more to decreased perfusion than embolus, and may explain why these patients' symptoms improve after STA-MCA anastomosis. The results of this study suggest that in addition to an inaccessible lesion, global or focal decreased rCBF is a necessary criterion in the definition of indications for intracranial revascularization procedures.
M. Peter Heilbrun, O. Howard Reichman, Robert E. Anderson and Theodore S. Roberts
Michael G. O'Sullivan, Patrick F. Statham, Patricia A. Jones, J. Douglas Miller, N. Mark Dearden, Ian R. Piper, Shirley I. Anderson, Alma Housley, Peter J. Andrews, Susan Midgley, Jane Corrie, Janice I. Tocher and Robin Sellar
✓ Previous studies have suggested that only a small proportion (< 15%) of comatose head-injured patients whose initial computerized tomography (CT) scan was normal or did not show a mass lesion, midline shift, or abnormal basal cisterns develop intracranial hypertension. The aim of the present study was to re-examine this finding against a background of more intensive monitoring and data acquisition.
Eight severely head-injured patients with a Glasgow Coma Scale score of 8 or less, whose admission CT scan did not show a mass lesion, midline shift, or effaced basal cisterns, underwent minute-to-minute recordings of arterial blood pressure, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) derived from blood pressure minus ICP. Intracranial hypertension (ICP ≥ 20 mm Hg lasting longer than 5 minutes) was recorded in seven of the eight patients; in five cases the rise was pronounced in terms of both magnitude (ICP ≥ 30 mm Hg) and duration. Reduced CPP (≤ 60 mm Hg lasting longer than 5 minutes) was recorded in five patients.
Severely head-injured (comatose) patients whose initial CT scan is normal or does not show a mass lesion, midline shift, or abnormal cisterns nevertheless remain at substantial risk of developing significant secondary cerebral insults due to elevated ICP and reduced CPP. The authors recommend continuous ICP and blood pressure monitoring with derivation of CPP in all comatose head-injured patients.
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.
David John Netherway, Amanda Helen Abbott, Peter John Anderson and David John David
In recent years, comparisons between intracranial volumes (ICVs) in patients with craniosynostosis and healthy patients have given variable results, leading to questions regarding the validity of the normal reference material and the comparability of the measurement techniques. In this study, ICVs in patients with nonsyndromal craniosynostosis without previous surgical intervention were compared with the ICVs of a normal population of European descent determined using the same method for each group.
Determination of ICV was based on measuring the area of intersection in each computerized tomography slice. For comparisons the ICV measurements for each patient were standardized with regard to age and sex by expressing them in terms of the standard deviation score.
Only the group of boys with metopic synostosis had a tendency toward smaller ICV than did healthy boys (p = 0.04). Partitioning the male metopic data into age groups younger and older than 7 months of age revealed that the younger children had normal ICVs, whereas the older children had, on average, smaller ICVs (p = 0.02). Both the female sagittal synostosis and the male unilateral coronal synostosis groups had larger than normal ICVs, both with a probability value less than 0.001.
No evidence was found that the ICVs of patients with nonsyndromal craniosynostosis are smaller than those of normal children, except for boys older than 7 months of age with metopic synostosis. This finding may have implications for the timing of surgical intervention for these patients. The indications are that interventions should be focused less on ICV and more on normalizing craniofacial shape and promoting normal development.
Richard C. E. Anderson, Peter Kan, Kris W. Hansen and Douglas L. Brockmeyer
Currently, no diagnostic or procedural standards exist for clearing the cervical spine in children after trauma. The purpose of this study was to determine if reeducation of nonneurosurgical personnel and initiation of a new protocol based on the National Emergency X-Radiography Utilization Study criteria could safely increase the number of pediatric cervical spines cleared of suspected injury without a neurosurgical consultation.
Data regarding cervical spine clearance in children (ages 0–18 years) after trauma protocol activation at Primary Children's Medical Center between 2001 and 2005 were collected and reviewed. Radiographic and clinical methods of clearing the cervical spine as well as the type and management of injuries were determined for two time frames: Period I (January 2001–December 2003) and Period II (January 2004–July 2005).
Between 2001 and 2003, 95% of 936 cervical spines were cleared of suspected injury by the neurosurgical service. Twenty-one ligamentous injuries (2.2%) and 12 fracture–dislocations (1.3%) were detected, with five patients requiring surgical stabilization (0.5%). Between January 2004 and July 2005, 507 (68%) of 746 cervical spines were cleared by nonneurosurgical personnel. Six ligamentous injuries (0.8%) and 10 fracture–dislocations (1.3%) were identified, with three patients (0.4%) requiring surgical stabilization. No late injuries were detected in either period.
The protocol used has been effective in enabling detection of cervical spine injuries in children after trauma, with the new protocol increasing by more than 60% the number of cervical spines cleared by nonneurosurgical personnel. Reeducation with establishment of the new protocols can safely facilitate clearance of the cervical spine by nonneurosurgical personnel after trauma.
Richard C. E. Anderson, Peter Kan, Wayne M. Gluf and Douglas L. Brockmeyer
Despite decades of surgical experience, the long-term consequences of occipitocervical (OC) and atlantoax-ial (C1–2) fusions in children are unknown. The purpose of this study was to determine the long-term effects of these fusions on growth and alignment of the maturing cervical spine.
A retrospective chart review was conducted for patients 6 years of age or younger (mean 4.7 years, range 1.7–6.8 years) who underwent OC or C1–2 fusion at the Primary Children’s Medical Center at the University of Utah within the last 10 years. Immediate postoperative plain radiographs and computed tomography (CT) scans were compared with the most recent plain and dynamic radiographs to assess changes in spinal growth and alignment.
Seventeen children met entry criteria for the study. All patients had fusion documented on follow-up radiography or CT scans. At a mean follow up of 28 months, there were no cases of sagittal malalignment (kyphotic or swanneck deformity), subaxial instability (osteophyte formation or subluxation), or unintended fusion of adjacent levels. The lordotic curvature of the cervical spine increased from a mean of 15° postoperatively to 27° at follow up (p = 0.06). A mean of 34% of the vertical growth of the cervical spine occurred within the fusion segment. When data were analyzed pertaining to a subgroup of five patients who underwent follow-up periods for longer than 48 months (mean 50.2 months, range 48–54 months), similar results were seen.
Preliminary follow-up results indicate that, compared with older children, children 6 years of age or younger undergoing OC or C1–2 fusion are not at an increased risk of spinal deformity or subaxial instability. Longer follow-up periods, during which measurements of the spinal canal are taken, will be necessary to determine precisely how children’s spines grow and remodel after an upper cervical spine fusion.
Vijayabalan Balasingam, Gregory J. Anderson, Neil D. Gross, Cheng-Mao Cheng, Akio Noguchi, Aclan Dogan, Sean O. McMenomey, Johnny B. Delashaw Jr. and Peter E. Andersen
The authors conducted a cadaveric anatomical study to quantify and compare the area of surgical exposure and the freedom available for instrument manipulation provided by the following four surgical approaches to the extracranial periclival region: simple transoral (STO), transoral with a palate split (TOPS), Le Fort I osteotomy (LFO), and median labioglossomandibulotomy (MLM).
Twelve unembalmed cadaveric heads with normal mouth opening capacity were serially dissected. For each approach, quantitation of extracranial periclival exposure and freedom for instrument manipulation (known here as surgical freedom) was accomplished by stereotactic localization. To quantify the extent of extracranial clival exposure obtained, anatomical measurements of the extracranial clivus were performed on 17 dry skull bases.
The values (means ± standard deviations in mm2) for periclival exposure and surgical freedom, respectively, for the surgical approaches studied were as follows: STO = 492 ± 229 and 3164 ± 1900; TOPS = 743 ± 319 and 3478 ± 2363; LFO = 689 ± 248 and 2760 ± 1922; and MLM 1312 ± 384 and 8074 ± 6451. The extent of linear midline clival exposure and the percentage of linear midline clival exposure relative to the total linear midline exposure were as follows, respectively: STO = 0.6 ± 4.9 mm and 7.8 ± 11%; TOPS = 8.9 ± 5.5 mm and 24.2 ± 16.7%; LFO = 32.9 ± 10.2 mm and 85.0 ± 18.7%; and MLM = 2.1 ± 4.4 mm and 6.7 ± 11.1%.
The choice of approach and the resulting degree of complexity and associated morbidity depends on the location of the pathological entity. The authors found that the MLM approach, like the STO approach, provided good exposure of the craniocervical junction but limited exposure of the clivus. The TOPS approach, an approach attended by a lesser risk of morbidity, provided adequate exposure of the extracranial inferior clivus. Maximal exposure of the extracranial clivus proper was provided by the LFO approach.