Veetai Li

Antimicrobial suture wound closure for cerebrospinal fluid shunt surgery: a prospective, double-blinded, randomized controlled trial

OBJECT Implantation of cerebrospinal fluid (CSF) shunting devices is associated with a 5-15% risk of infection as cited in contemporary pediatric neurosurgical literature. Shunt infections typically require complete removal of the device and prolonged antibiotic treatment followed by shunt replacement. Moreover, shunt infections are commonly associated with prolonged hospital stays, potential comorbidity, and the increased risk of neurological compromise due to ventriculitis or surgical complications. The authors prospectively evaluated the incidence of CSF shunt infection following shunt procedures performed using either antimicrobial suture (AMS) or conventional suture. METHODS In a single-center, prospective, double-blinded, randomized controlled trial, the authors enrolled 61 patients, among whom 84 CSF shunt procedures were performed over 21 months. Randomization to the study (AMS) or control (placebo) group was stratified to minimize the effect of known shunt infection risk factors on the findings. Antibacterial shunt components were not used. The primary outcome measure was the incidence of shunt infection within 6 months of surgery. RESULTS The shunt infection rate in the study group was 2 (4.3%) of 46 procedures and 8 (21%) of 38 procedures in the control group (p = 0.038). There were no statistically significant differences in shunt infection risk factors between the groups (procedure type and time, age < 6 months, weight < 4 kg, recent history of shunt infection). No suture-related adverse events were reported in either group. CONCLUSIONS These results support the suggestion that the use of AMS for CSF shunt surgery wound closure is safe, effective, and may be associated with a reduced risk of postoperative shunt infection. A larger randomized controlled trial is needed to confirm this association.

Serial Radiography in the Infant Shaken Impact Syndrome

Certain CT and/or MRI abnormalities have been used medicolegally to time intracranial injuries from the infant shaken impact syndrome (ISIS). For example, parenchymal hypodensities on CT scans are said to arise only after 6–48 h have elapsed postinjury, and the presence of chronic or mixed subdural hematomas suggests injury that occured 1–4 weeks prior. However, these statements are based largely upon inference from data obtained in other conditions such as ischemic anoxic injury and chronic subdural hemorrhage in adults. Direct evidence about the evolution of intracranial injuries in infants with ISIS is sparse, and the radiographic changes following ISIS have never been systematically studied on serial imaging studies. One hundred-seventeen serial CT and MRI scans obtained from 33 infants with ISIS were reviewed retrospectively. The exact scan dates and times were obtained directly from the scans. Acute subdural hemorrhage was the most common intracranial abnormality and was present in 27 (81%) of the 33 infants. Other intracranial abnormalities included chronic subdural collections, subarachnoid hemorrhage, epidural hematomas, parenchymal hypodensities, edema and contusions, and atrophy and encephalomalacia. In 15 of the 33 infants, the injury could be timed with reasonable certainty, and the evolution of the radiographic changes followed over time. Six of the 15 infants had evidence of prior cranial trauma such as chronic subdural collections (5 infants) or mild atrophy (1 infant). Of the remaining 9 infants, parenchymal abnormalities such as hypodensities, edema and contusion appeared in virtually all of the initial scans performed approximately 3 h following the report of injury. One ‘chronic’ subdural collection was absent on the first scan performed 2.75 h postinjury, but appeared on a second scan performed 17 h later, suggesting that some ‘chronic’ subdural fluid collections may arise much sooner than previously thought. These findings challenge some of the current dogma about the timing of radiographic changes following abuse and are important in timing the alleged abuse for legal purposes.

AtlantoAxial Rotatory Fixation: Part 3—A Prospective Study of the Clinical Manifestation, Diagnosis, Management, and Outcome of Children with AlantoAxial Rotatory Fixation

OBJECTIVE:This is a prospective study of the clinical manifestations, diagnostic motion analysis, management, and outcome of children with atlantoaxial rotatory fixation (AARF). METHODS:Fifty children presenting with painful torticollis were subjected to the three-head positions diagnostic computed tomographic scanning protocol described in Part II of our AARF study. Twenty-nine children qualified as having AARF (8 Type I, 11 Type II, and 10 Type III), and six children were classified in the diagnostic gray zone (DGZ). The AARF patients were given either halter or calipers traction depending on the type and chronicity of pretreatment delay. Upon reduction, patients were immobilized with either a cervicothoracic brace or a halo. Recurrence of AARF on halo and patients whose deformity was not reducible were given posterior C1C2 fusion at the best achievable alignment. The difficulty and results of treatment were measured according to the following: duration of traction, number of reduction slippage, percent not reducible by traction, percent needing halo, percent needing fusion, total duration of treatment, total number of treatment procedures, and percent who lost normal C1C2 dynamics. Results were compared between groups stratified by AARF types, by chronicity of pretreatment delay (acute ≪ 1 mo, subacute = 1–3 mo, chronic ≥ 3 mo) and by the presence or absence of recurrence (recurrent AARF defined as having two or more slippages). DGZ patients were treated with only comfort measures for 2 weeks and then restudied. Only those children with persistent symptoms and DGZ or worse motion dynamics were given traction and bracing. RESULTS:Neither age nor etiology significantly influenced the severity of AARF. There was only a slight tendency for children younger than 5 years, and for trauma, to associate with severe C1C2 interlock. Delay of treatment up to 11 months did not result in improvement of the neck restriction or in abatement of pain. In fact, there are strong suggestions that prolonged delay could lead to worsening of the rotatory dynamics: Type I AARF are highly correlated with delays longer than 3 months and Type III with delays less than 1 month. Also, four patients who had serial motion studies during the delay period showed clear worsening in the pathological stickiness in C1C2 rotation. In addition, chronic rotatory deformity led to progressive occiput −C1 separation or laxity teleologically to compensate for a skewed visual axis. The mean occiput −C1 separation angle for chronic patients was 31.2° versus 5° for acute patients and less than 3° for normal children. The difficulty and duration of treatment, the number of reslippage after reduction, the rate of irreducibility, the need for halo and fusion, and the percentile of patients ultimately loosing normal C1C2 rotation were significantly greater with Type I patients than Type III patients, with Type II patients being intermediate. Likewise, chronic patients of all AARF types were much worse in all parameters than acute patients; subacute patients were closer to chronic patients in complexity and outcome. Severity and chronicity exerted independent effects on outcome, and the worse identifiable subgroup were the chronic Type I patients versus the best subgroup of acute Type III patients. Thirteen patients developed recurrent AARF; they had much worse prognosis in all aspects measured than nonrecurrent patients. Recurrence was adversely influenced by both the severity (type) and chronicity of AARF. Half of the DGZ patients resolved with analgesics, but two of six remained symptomatic and in DGZ dynamics, and one deteriorated to Type III AARF. Two of those three patients responded easily to traction and bracing, and one was lost to follow-up. CONCLUSION:Children with painful torticollis should be subjected to the three-position computed tomographic diagnostic protocol, not only to secure the diagnosis of AARF but also to grade the severity of the condition by virtue of the dynamic motion curve. Closed reduction with traction should be instituted immediately to avoid the serious consequences of chronic AARF. Proper typing and reckoning of the pretreatment delay are requisites for selecting treatment modalities. Recurrent dislocation and incomplete reduction should be treated with posterior C1C2 fusion in the best achievable alignment. Open reduction and halo immobilization to avoid permanent fixation can be tried with select cases.

Cranial Birth Injuries in Term Newborn Infants

While cranial birth injuries in term infants are well recognized, to date, only small case series have been described. In an attempt to further define the spectrum of cranial birth injuries, we analyzed 41 consecutive cranial birth injuries at our institution over the period 1991–1998. The most common clinical presentations were apnea (39%) and seizures (37%). Average Apgar scores were 5.7 at 1 min and 7.3 at 5 min; 54% of infants had abnormally low Apgar scores at 1 min and 31% had abnormally low scores at 5 min. The most common intracranial lesion was subdural hemorrhage, present in 73% of infants; most had either a tentorial (57%) and/or interhemispheric (50%) location. Operative treatment was required in 5 infants (12%). Two of the 41 infants (4.8%) died. The study group was compared with a control group of 63 randomly selected births without cranial injury. Using a stepwise logistic regression model, independently significant variables included neonatal birth weight, Apgar scores at 1 and 5 min and mode of delivery. Compared with the controls, the study group had a significantly higher incidence of forceps and/or vacuum deliveries. Combining vacuum, forceps and urgent cesarean section deliveries together as ‘urgent’ and elective cesarean and spontaneous vaginal deliveries as ‘nonurgent’, we could find no significant differences between these two groups. Our data conflict with those of Towner et al. [N Engl J Med 1999;341:1709–1714], and suggest that the method of assisted delivery, rather than the urgency of the delivery or dysfunctional labor per se, is a more important variable in cranial birth injuries.

Immediate Posttraumatic Seizures: Is Routine Hospitalization Necessary?

Objective: A recent Internet survey of pediatric neurosurgeons showed that 86% routinely admitted children with immediate posttraumatic seizures (PTS) for a brief period of observation. We wished to determine whether certain children meeting predefined criteria could instead be safely discharged from the emergency room. Methods: We reviewed the records of children admitted during the past 5 years with a diagnosis of seizure and head injury. Children with a minor head injury, a PTS occurring within 24 h of injury and no intracranial abnormalities on admission CT scan were included. Children with previous neurological conditions, a history of prior seizures (other than PTS or febrile seizures), a prior history of anticonvulsant use, or intracranial abnormalities on the admission CT scan were excluded. Records were abstracted for child’s age, gender, length of admission, previous history of PTS or febrile seizures, mechanism of injury, location of impact, time between impact and PTS, the number, length and type of PTS, Glasgow Coma Score (GCS) on admission, subsequent complications and hospital costs. Results: Seventy-one children met the inclusion criteria. Eleven children presented to the emergency room with prolonged seizures, transient apnea or persistently low GCS and required admission to the intensive care unit (ICU). Among the 60 remaining children with simple PTS, none had further seizures during the follow-up period, and none had significant complications. The average cost of hospitalization was known for 58 children; after excluding the costs for 5 patients who were admitted to the ICU, the average hospital cost amounted to USD 1,615 per patient. Conclusions: Our data suggest that children with isolated minor head injuries and simple PTS who recover fully in the emergency room, whose CT scans show no intracranial abnormalities and who have no prior history of neurological disease, epilepsy or anticonvulsant use are at low risk for recurrent seizures or neurological complications, and could potentially be sent home to a reliable caretaker and a stable home situation. However, because of the limited sample size in this study, the statistical risk of a bad outcome may be as high as 9%; we therefore suggest that much larger studies are potentially needed before this becomes a standard policy.

The Embryogenesis of Congenital Vertebral Dislocation: Early Embryonic Buckling?

Congenital vertebral dislocation (CVD) is a rare congenital spinal malformation characterized by a translatory or rotatory vertebral displacement, or both, at a single level, that results in an abrupt angulation of the neural canal. The more caudal vertebra is dysplastic and appears at first glance to be posteriorly dislocated into the vertebral canal as a posterior hemivertebra, but is actually well aligned with the more caudal vertebral column. Unfortunately, the present classification of complex congenital vertebral anomalies is confusing, and CVD has been grouped together with other congenital vertebral malformations under the terms ‘segmental spinal dysgenesis’, ‘medial spinal aplasia’, and others. Moreover, a putative embryonic mechanism has never been proposed for CVD. Based upon our experience with 6 children and a critical review of the literature, we identify CVD as a distinct entity having characteristic anatomical features. We propose a novel putative embryonic mechanism – early embryonic ‘buckling’ – which likely occurs by the 6th embryonic week, prior to the period of axonal outgrowth and the beginning of vertebral chondrification.

Low-Pressure Shunt ‘Malfunction’ following Lumbar Puncture in Children with Shunted Obstructive Hydrocephalus

Most shunt malfunctions present with signs and symptoms of high intracranial pressure, and computed tomography scans demonstrate ventricular enlargement. However, several authors have described a rare ‘low-pressure’ hydrocephalic state in which ventricular enlargement can occur in the face of low, or even negative, intracranial pressures. We report 2 children with obstructive hydrocephalus in whom this ‘low-pressure state’ followed a lumbar puncture; in both children, the shunts were functioning properly despite increased ventricular size on computed tomography scans, and all symptoms resolved (and the ventricles returned to baseline) following a period of enforced recumbency without shunt revision. We hypothesize that subarachnoid cerebrospinal fluid leakage through the puncture site in the lumbar theca decreases the intracranial pressures globally to a point below the opening pressures of the shunt valves. The ventricular cerebrospinal fluid, unable to be drained through either the subarachnoid space or the shunt, accumulates within the ventricular system under low pressure. One consistent feature in our 2 patients has been the postural nature of the headaches. We recommend enforced recumbency and, if necessary, a blood patch to seal the lumbar leakage. Shunt revision or prolonged external ventricular drainage appears to be unnecessary in these patients. Finally, neurosurgeons should be aware of this potential complication.

Pediatric neurosurgical disease.

The most common, primary referrals to a pediatric neurosurgeons office are the evaluation and management of the child with a large head (to rule out hydrocephalus and other space occupying lesions) a mishappen head (to rule out various forms of craniosynostosis), or some form of congenital spinal abnormality (spinal dysraphism). The authors discuss the pathogenesis and clinical features of these disorders, provide a framework for diagnostic evaluation and referral, and discuss the various treatment options available for each.

Midcervical Postinfectious Ligamentous Instability: A Variant of Grisel’s Syndrome

Objective and Importance: We report our recent experience with two cases of C3–C4 ligamentous instability that developed after the onset of an upper airway infection. To our knowledge, this is the first report in the literature of a variant of Grisel’s syndrome occurring at the midcervical levels. The diagnosis and management of this entity are presented. Clinical Presentation: Two infants with respiratory distress were evaluated at the Children’s Hospital of Buffalo. During evaluation, cervical spine x-rays showed midcervical translational instability. Neither patient had a neurological deficit nor a history of trauma or bone disease. Intervention: One of the patients was immmobilized with an external orthosis. Conclusion: Each patient remained neurologically intact, and the cervical spine returned to normal alignment after several months. We discuss a possible mechanism for this unusual association and recommend external immobilization.

The Role of Somatosensory Evoked Potentials in the Evaluation of Spinal Cord Retethering

Early detection of clinically significant spinal cord retethering is of paramount importance for the preservation of neurologic function in patients with repaired spinal dysraphic lesions. We retrospectively analyzed 90 children who were followed with serial peroneal somatosensory evoked potentials (SEPs) after a repair of their spinal dysraphic lesions with the objective of evaluating whether SEPs were a useful way of monitoring these children to facilitate early detection of clinically significant retethering. Three hundred and nine studies were performed on these children yielding a mean of 3.4 studies per patient. The median time between SEP studies was 13 months. A clinical examination was performed at the time each SEP was done. Sixty-one patients (68%) had a myelomeningocele; 25 (28%) had a lipomyelomeningocele while other types of dysraphic lesions were found in the remaining 4%. Nineteen patients (21%) had no change in serial SEPs; 7 of these 19 (37%) had a deterioration in clinical status while the SEPs were stable. Twenty-six patients (29%) showed improvement in serial SEPs, however, 3 of the 26 had clinical worsening at the time SEPs improved. SEPs deteriorated in 45 patients (50%); 13 of the 45 had an associated clinical deterioration, and the remaining 32 were stable clinically. Twenty-three patients (26%) had a clinical deterioration; of these only 13 had a corresponding deterioration in SEPs, 7 patients had stable SEPs while 3 had improvement in SEPs at the time of clinical deterioration. This results in a false-positive rate of 71% and a false-negative rate of 43%. We conclude that serial SEPs do not correlate well with clinical status and are not a useful modality for monitoring patients at risk for retethering.