Denis S. Drummond

Neurophysiological detection of impending spinal cord injury during scoliosis surgery.

BACKGROUND Despite the many reports attesting to the efficacy of intraoperative somatosensory evoked potential monitoring in reducing the prevalence of iatrogenic spinal cord injury during corrective scoliosis surgery, these afferent neurophysiological signals can provide only indirect evidence of injury to the motor tracts since they monitor posterior column function. Early reports on the use of transcranial electric motor evoked potentials to monitor the corticospinal motor tracts directly suggested that the method holds great promise for improving detection of emerging spinal cord injury. We sought to compare the efficacy of these two methods of monitoring to detect impending iatrogenic neural injury during scoliosis surgery. METHODS We reviewed the intraoperative neurophysiological monitoring records of 1121 consecutive patients (834 female and 287 male) with adolescent idiopathic scoliosis (mean age, 13.9 years) treated between 2000 and 2004 at four pediatric spine centers. The same group of experienced surgical neurophysiologists monitored spinal cord function in all patients with use of a standardized multimodality technique with the patient under total intravenous anesthesia. A relevant neurophysiological change (an alert) was defined as a reduction in amplitude (unilateral or bilateral) of at least 50% for somatosensory evoked potentials and at least 65% for transcranial electric motor evoked potentials compared with baseline. RESULTS Thirty-eight (3.4%) of the 1121 patients had recordings that met the criteria for a relevant signal change (i.e., an alert). Of those thirty-eight patients, seventeen showed suppression of the amplitude of transcranial electric motor evoked potentials in excess of 65% without any evidence of changes in somatosensory evoked potentials. In nine of the thirty-eight patients, the signal change was related to hypotension and was corrected with augmentation of the blood pressure. The remaining twenty-nine patients had an alert that was related directly to a surgical maneuver. Three alerts occurred following segmental vessel clamping, and the remaining twenty-six were related to posterior instrumentation and correction. Nine (35%) of these twenty-six patients with an instrumentation-related alert, or 0.8% of the cohort, awoke with a transient motor and/or sensory deficit. Seven of these nine patients presented solely with a motor deficit, which was detected by intraoperative monitoring of transcranial electric motor evoked potentials in all cases, and two patients had only sensory symptoms. Somatosensory evoked potential monitoring failed to identify a motor deficit in four of the seven patients with a confirmed motor deficit. Furthermore, when changes in somatosensory evoked potentials occurred, they lagged behind the changes in transcranial electric motor evoked potentials by an average of approximately five minutes. With an appropriate response to the alert, the motor or sensory deficit resolved in all nine patients within one to ninety days. CONCLUSIONS This study underscores the advantage of monitoring the spinal cord motor tracts directly by recording transcranial electric motor evoked potentials in addition to somatosensory evoked potentials. Transcranial electric motor evoked potentials are exquisitely sensitive to altered spinal cord blood flow due to either hypotension or a vascular insult. Moreover, changes in transcranial electric motor evoked potentials are detected earlier than are changes in somatosensory evoked potentials, thereby facilitating more rapid identification of impending spinal cord injury.

Comparison of Titanium Elastic Nails with Traction and a Spica Cast to Treat Femoral Fractures in Children

BACKGROUND Titanium elastic nails are commonly used to stabilize femoral fractures in school-aged children, but there have been few studies assessing the risks and benefits of this procedure compared with those of traditional traction and application of a spica cast. This prospective cohort study was designed to evaluate these two methods of treatment, with a specific focus on the first year after injury, the period when the treatment method should have the greatest impact. METHODS Eighty-three consecutive children, six to sixteen years of age, were studied prospectively. Factors that were analyzed included clinical and radiographic data, complications, hospital charges, and outcome data. Outcome and recovery were assessed both with the American Academy of Orthopaedic Surgeons Pediatric Outcomes Data Collections Instrument, version 2.0, and according to a series of important recovery milestones including the time to walking with aids, time to independent walking, time absent from school, and time until full activity was allowed. RESULTS Thirty-five children (thirty-five fractures), with a mean age of 8.7 years, were treated with traction and application of a spica cast, and forty-eight children (forty-nine fractures), with a mean age of 10.2 years, were treated with titanium elastic nails. All fractures healed, and no child sustained a complication that was expected to cause permanent disability. At one year after the fracture, eighty of the children had acceptable alignment and no inequality between the lengths of the lower extremities. The remaining three children, who had an unsatisfactory result, had been treated with traction and a spica cast. Twelve patients (34%) treated with traction and a cast had a complication compared with ten patients (21%) treated with titanium elastic nails. Compared with the children treated with traction and a cast, those treated with titanium elastic nails had shorter hospitalization, walked with support sooner, walked independently sooner, and returned to school earlier. These differences were significant (p < 0.0001). We could detect no difference in total hospital charges between the two groups. CONCLUSIONS The results of this prospective study support the recent empiric observations and published results of retrospective series indicating that a child in whom a femoral fracture is treated with titanium elastic nails achieves recovery milestones significantly faster than a child treated with traction and a spica cast. Hospital charges for the two treatment methods are similar. The complication rate associated with nailing compares favorably with that associated with traction and application of a spica cast.

Complications in children managed with immobilization in a halo vest.

Thirty-seven patients who were three to sixteen years old were managed with immobilization in a halo vest between 1987 and 1993. Twenty-four patients (65 per cent) had the halo vest applied in conjunction with operative arthrodesis of the cervical spine; the remaining thirteen patients (35 per cent) had the halo vest applied to immobilize the cervical spine after trauma. Complications occurred in twenty-five patients (68 per cent). Pin-site infections were the most common complications, developing in twenty-two patients. Grade-II infections (purulent drainage) developed more frequently in children who were eleven years old or more: they were identified in five of fourteen such patients, compared with two of twenty-three patients who were ten years old or less. There was a tendency toward more grade-I infections (non-purulent drainage, with or without erythema) and loosening of the pins in the children who were ten years old or less: eleven of twenty-three such patients had each of those complications, compared with four of fourteen children who were eleven years old or more. Both loosening and infection occurred more frequently at the anterior pin sites. Other complications included one dural penetration, one transient injury of the supraorbital nerve, and three pin-site scars that were considered by the family to be objectionable. There were no complications related to the vest part of the halo vest. Younger patients who had a halo construct with more than four pins (multiple-pin constructs) had a similar rate of complications compared with patients who were managed with a standard four-pin halo construct.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonographic evaluation of the elbow in infants and young children after suspected trauma.

Fractures and epiphyseal injuries in the region of the elbow are uncommon in infants and young children, but they can be very difficult to diagnose and delineate accurately. In addition to plain radiography, invasive or costly procedures such as arthrography and magnetic resonance imaging traditionally have been used to evaluate these injuries. We used high-resolution real-time ultrasonography to evaluate a suspected injury of the elbow in seven infants and one ten-year-old child. Three of the infants had a physeal separation, two had a supracondylar fracture, and two had no skeletal injury. The child had an avulsion fracture of the lateral epicondyle of the humerus and an effusion in the joint. The ultrasonographic findings were confirmed by arthrography in three patients, by open reduction in one, and by follow-up radiographs in all. None of the ultrasonographic studies were performed with the patient under general anesthesia. Ultrasonography, a readily available, non-invasive technique, can be used to evaluate the unossified epiphysis about the elbow of infants and young children; to demonstrate dislocations, fractures, and physeal separations; to identify a hinge of soft tissue at the site of a fracture; to identify interposition of soft tissue between fracture fragments; and to aid in the planning of closed and open reductions.

Complications of posterior arthrodesis of the cervical spine in patients who have Down syndrome.

Ten patients who had Down syndrome and had had a posterior arthrodesis of the upper cervical spine were studied. The mean age at the time of the operation was 8.9 years, and the patients had been followed for three days to forty-nine months. Complications related to the operation occurred in all patients. They included infection and dehiscence at the site of the wound, incomplete reduction of the atlanto-axial joint, instability of the adjacent motion segment, neurological sequelae, resorption of the autogenous bone graft, and death in the postoperative period. Resorption of the bone graft, which occurred in six of the patients, has not previously been reported in patients who have Down syndrome, to our knowledge. Several theoretical mechanisms for this complication are proposed. We recommend non-operative management for patients who have Down syndrome and atlanto-axial instability without neurological signs or symptoms. If the severity of symptoms necessitates a posterior arthrodesis, a high rate of complications must be anticipated.

Occipitalization of the atlas in children. Morphologic classification, associations, and clinical relevance.

BACKGROUND Occipitalization is defined as a congenital fusion of the atlas to the base of the occiput. We are not aware of any previous studies addressing the morphologic patterns of occipitalization or the implications of occipitalization in children. We present data on what we believe is the largest reported series of children with occipitalization studied with computed tomography and/or magnetic resonance imaging, and we provide a description of their clinical characteristics. METHODS We retrospectively reviewed all cases of occipitalization in children included in our spine database. Patient charts and imaging studies were reviewed. A new morphologic classification of occipitalization was developed from the two-dimensional sagittal and coronal reformatted computed tomographic reconstructions and/or magnetic resonance images. The classification includes four patterns according to the anatomic site of occipitalization (Zones 1, 2, and 3 and a combination of those zones), and it was applied to this group of patients. Imaging studies were also reviewed for evidence of cervical instability and for other anomalies of the craniovertebral junction. RESULTS Thirty patients with occipitalization were identified. There were twenty-four boys and six girls with a mean age of 6.5 years. The morphologic categorization was Zone 1 (a fused anterior arch) in six patients, Zone 2 (fused lateral masses) in five, Zone 3 (a fused posterior arch) in four, and a combination of fused zones in fifteen. Seventeen patients (57%) had atlantoaxial instability, and eight of them had an associated C2-C3 fusion. Eleven patients (37%) had spinal canal encroachment, and five of them had clinical findings of myelopathy. The highest prevalence of spinal canal encroachment (63%) was noted in patients with occipitalization in Zone 2. CONCLUSIONS Occipitalization is associated with abnormalities that lead to narrowing of the space available for the spinal cord or brainstem. The risk of atlantoaxial instability developing is particularly high when there is an associated congenital C2-C3 fusion. Two-dimensional sagittal and coronal reformatted computed tomographic reconstructions and/or magnetic resonance images can help to establish the diagnosis and permit categorization of occipitalization in three zones, each of which may have a different prognostic implication.

Screw fixation of Grade III slipped capital femoral epiphysis.

From 1987 to 1992, 161 children were treated at The Childrens Hospital of Philadelphia for slipped capital femoral epiphysis. Of these, 23 patients (23 hips) had Grade III slips (> 50%). Fixation was achieved by 1 or 2 screws in all patients. Twenty-one of 23 patients were available for followup (average followup, 2.8 years). Four slips were acute, 11 were acute-on-chronic, and 6 were chronic. At the most recent followup, radiographs were taken and a Harris Hip Score was assigned for each patient. Stabilization without progression of slip at followup was achieved in all patients. Screw placement was satisfactory per the criteria of Stambough in all patients. Four children (19%) had major complications: Three (1 acute slip and 2 acute-on-chronic slips) had avascular necrosis of the femoral head; One (chronic slip) had chondrolysis. There were no immediate postoperative complications. The mean Harris Hip Score for these 4 patients was 85 points, versus a mean score of 94 points for all 21 patients. Chronic Grade III slipped capital femoral epiphysis can be treated safely and effectively by screw fixation. Five of 6 patients had satisfactory results; the only exception had evidence of chondrolysis preoperatively. Acute and acute-on-chronic Grade III slipped capital femoral epiphyses treated with screw fixation are less predictable. In 15 patients, reduction occurred in 9 hips despite deliberate avoidance of forceful manipulative maneuvers. Avascular necrosis developed in 3 (33%) of these 9 hips. Reduction of the acute component of the slip during screw fixation, whether deliberate or not, indicates gross instability. It is hypothesized that avascular necrosis may be associated with injury to the epiphyseal vasculature occurring at the time of the acute slip.

Pediatric fracture without radiographic abnormality : Description and significance

With an expanding application of magnetic resonance imaging in acute musculoskeletal injury, an increasing number of occult traumatic lesions of bone are being identified. The authors describe the entity of fracture without radiographic abnormality, which as the name suggests is a bony injury not apparent on plain radiographs. The clinical significance and potential sequelae have not been defined in the pediatric patient. Accordingly, the purpose of this study is to describe and classify the entity of the pediatric fracture without radiographic abnormality and delineate its importance and appropriate management. Twenty-five children were seen primarily or referred to The Childrens Hospital of Philadelphia after having sustained an acute traumatic injury; all refused to bear weight or use their extremity, and all had initial plain radiographs that were interpreted as normal. Subsequent magnetic resonance images of all 25 children showed an occult fracture. These included Salter-Harris fracture Types II (two patients), III (one patient), and IV (three patients), intraosseous epiphyseal fractures (18 patients), and a metaphyseal diaphyseal fracture (one patient). Four patients with intraosseous epiphyseal fractures ultimately sloughed a portion of their articular cartilage, as observed at arthroscopy. The decision to proceed with magnetic resonance imaging in the evaluation of a child who refuses to use an extremity depends on many variables. However, magnetic resonance imaging has proven useful in revealing fractures without radiographic abnormality and in ruling out other pathosis.

Traumatic atlanto-occipital dislocation in children

BACKGROUND Traumatic atlanto-occipital dislocation in children and adolescents is a rare and often fatal injury. Although historically most reported cases have been fatal, the advent of modern prehospital care has led to an increase in survival following this injury. As a consequence, some patients may achieve or maintain satisfactory neurologic function following early intervention, stabilization, and definitive management. We analyzed the data on children and adolescents in whom traumatic atlanto-occipital dislocation had been treated with modern resuscitation techniques at our institution. METHODS Atlanto-occipital dislocation is defined as disruption of the ligaments and other supporting soft tissues as indicated by displacement in either a transverse or vertical direction. With use of the Trauma Registry database at our institution, we identified sixteen such injuries that had occurred between 1986 and 2003. The hospital charts, clinic notes, and radiographs were reviewed. A careful neurological evaluation was performed for all of the survivors at the time of the latest follow-up. RESULTS The mean age of the sixteen patients at the time of the injury was 7.6 years. The mechanisms of injury were diverse. The mean Glasgow Coma Scale score was 7.4 points. Eleven of the sixteen patients underwent intubation in the field, two were intubated in the emergency department, and three were not intubated. Eight of the sixteen patients were declared dead on arrival in the emergency department. The eight surviving patients initially were immobilized with either a halo vest or another orthosis. All patients except one received intravenous steroids in the emergency department. Three of the patients who survived the initial injury subsequently died while undergoing neurosurgical procedures for the treatment of extensive intracranial injuries. Four of the remaining five survivors underwent occiput-C2 fusion, and one was managed with a Minerva cast. At the time of the final follow-up, at a mean of 4.2 years after the injury, one patient was neurologically normal, three had mild spastic hemiparesis and were very functional, and one had spastic quadriplegia and was ventilator-dependent. CONCLUSIONS Prompt recognition and treatment of traumatic atlanto-occipital dislocation in children and adolescents can result in improved survival. Early diagnosis, prompt intubation, early and adequate immobilization of the head and neck, and the use of intravenous steroids appear to facilitate survival. We recommend arthrodesis from the occiput to C2 (or the nearest adjacent intact and stable vertebra caudad to C2) for all children who survive a traumatic atlanto-occipital dislocation, particularly those with an incomplete spinal cord injury.

Occipitocervical arthrodesis in children. A new technique and analysis of results.

A new wiring technique for occipitocervical arthrodesis was used in sixteen consecutive children between 1985 and 1992. The twelve boys and four girls had an average age of nine years and six months (range, two years and five months to nineteen years and three months) at the operation. The arthrodesis was performed between the occiput and the second cervical vertebra in ten patients and between the occiput and the third cervical vertebra in six. The instability was related to congenital anomalies (six patients), decompression for cervical stenosis (four patients), Down syndrome (three patients), trauma (one patient), resection of a tumor (one patient), and neurofibromatosis (one patient). Six patients needed a laminectomy for decompression because of cervical stenosis or for removal of a tumor. All of the patients were managed with an autogenous bone graft from the iliac crest and postoperative immobilization with a halo device. Fusion was achieved in fifteen of the sixteen patients. Complications developed in seven patients. The use of wire fixation, combined with the inherent stability of the bone-graft construct, allowed for removal of the halo device relatively early (range, six to twelve weeks), before the fusion was fully mature. No graft was displaced. All of the patients were followed at least until there was radiographic evidence of fusion (fifteen patients) or until a reoperation was performed (one patient). The average duration of follow-up was thirty-seven months (range, twelve to 108 months).