Walter F. Krengel

Early versus delayed surgery for acute cervical spinal cord injury.

The optimal timing of surgical intervention in cervical spinal cord injuries has not been defined. The goals of the study were to investigate changes in neurologic status, length of hospitalization, and acute complications associated with surgery within 3 days of injury versus surgery more than 3 days after the injury. All patients undergoing surgical treatment for an acute cervical spinal injury with neurologic deficit at two institutions between March 1989 and May 1991 were reviewed retrospectively. Forty-three patients initially were evaluated. At one institution, patients with neurologic spinal injuries had surgical intervention within 72 hours of injury. At the other institution, patients underwent immediate closed reduction with subsequent observation of neurologic status for 10 to 14 days before undergoing surgical stabilization. This study indicates that patients who sustain acute traumatic injuries of the cervical spine with associated neurologic deficit may benefit from surgical decompression and stabilization within 72 hours of injury. Surgery within 72 hours of injury in patients sustaining acute cervical spinal injuries with neurologic involvement is not associated with a higher complication rate. Early surgery may improve neurologic recovery and decrease hospitalization time in patients with cervical spinal cord injuries.

Early stabilization and decompression for incomplete paraplegia due to a thoracic-level spinal cord injury

All patients treated between 1985 and 1990 for acute incomplete spinal cord injury between T2 and T11 were retrospectively studied. This level was chosen for study because by excluding cervical cord, conus, and cauda equina injuries, neurologic improvement could be attributed to improvement of spinal cord function. Only 14 patients with incomplete thoracic level paraplegia were identified, representing 1.2% of all spinal injuries. All 14 patients were treated by early operative reduction, stabilization, or decompression. Tweive patients had surgery within 24 hours of neurologic injury, one at 36 hours, and one at 5 days. Twelve patients had initial posterior instrumentation and fusion, one of whom subsequently had an anterior decompression. Two patients had initial anterior decompression and fusion. Both later had posterior instrumentation and fusion to treat progressive deformity. Follow-up averaged 20 months (range, 9–65 months). Neural function before surgery and at follow-up was given a Frankel grade and lower extremity motor index score. Of 13 surviving patients, seven were initially Frankel B and six Frankel C. Of the seven patients initially Frankel B, four recovered to Frankel E, two improved to Frankel D, and one remained Frankel B. Of the six patients originally Frankel C, five recovered to Frankel E and one improved to Frankel D. Average neurologic improvement was 2.2 Frankel grades per patient, lower extremity motor index improved from an average of 7 to 44. Early surgical reduction, stabilization, and decompression is safe and improves neurologic recovery in comparison to historical controls treated by postural reduction or late surgical intervention.

The lateral capitellohumeral angle in normal children: mean, variation, and reliability in comparison to Baumann's angle.

Background Angular deformity is the most common complication of supracondylar humerus fracture. Baumanns angle (BA) is an established radiographic measure of coronal plane deformity after this injury. Numerous radiographic methods have been used to assess sagittal plane deformity, however, the mean, variability, and reliability of these measures has not been established. The purpose of this study was to determine the mean, SD, and intraobserver/interobserver reliability of the lateral capitellohumeral angle (LCHA) in children without evidence of fracture and compare them with those of BA. Methods Seventy-one sets of anteroposterior and lateral elbow radiographs were selected and stratified into 6-year age categories with equal number of males and females in each category. Five physicians performed 3 separate measurements of LCHA and BA on each film set. Statistical calculations were performed to determine mean, SD, measurement reliability, and differences between patients groups. Results The mean LCHA ±1 SD and BA ±1 SD measurements were 50.8±6 degrees and 71.5±6.2 degrees, respectively, and did not vary significantly by age, side, or sex (P>0.05). The LCHA showed good intraobserver (correlation coefficient 0.67) and fair interobserver (0.37) reliability, whereas BA showed excellent intraobserver (0.86) and interobserver (0.80) reliability. The expected SD for repeated measurement of a radiograph by a single observer was 2.6 degrees for BA and 5.2 degrees for LCHA. Conclusions The LCHA is a simple measurement to perform using digital tools. In normal elbows, the mean angle is 51±6 degrees and does not vary by age, side, or sex. LCHA variability in normal elbow radiographs is similar to BA. Its reliability is inferior to BA, but improves with age. Sagittal angulation abnormality of at least 12 degrees (<39 or >63 degrees) is necessary to be confident that the change is not because of measurement error alone. Further research is needed to better define the relationship of sagittal plane angular deformity to clinical outcome. Level of Evidence Diagnostic study with poor reference standard, Level IV.

Complex pediatric cervical spine surgery using smaller nonspinal screws and plates and intraoperative computed tomography

OBJECT The treatment of craniocervical instability in children is often challenging due to their small spine bones, complex anatomy, and unique syndromes. The authors discuss their surgical experience with 33 cases in the treatment of 31 children (≤ 17 years of age) with craniocervical spine instability using smaller nontraditional titanium screws and plates, as well as intraoperative CT. METHODS All craniocervical fusion procedures were performed using intraoperative fluoroscopic imaging and electrophysiological monitoring. Nontraditional spine hardware included smaller screw sizes (2.4 and 2.7 mm) from the orthopedic hand/foot set and mandibular plates. Twenty-three of the 33 surgical procedures were performed with intraoperative CT, which was used to confirm adequate position of the spine hardware and alignment of the spine. RESULTS The mean patient age was 9.5 years (range 2-17 years). Eleven children underwent a posterior C1-2 transarticular screw fusion, 17 had an occipitocervical fusion, and 3 had a posterior subaxial cervical fusion. The follow-up duration ranged from 9 to 72 months (mean 53 months). All children demonstrated successful fusion at their 3-month follow-up visit, except 1 patient whose unilateral C1-2 transarticular screw fusion required a repeat surgery before proper fusion was achieved. Of the 47 C1-2 transarticular screws that were placed, 13 were 2.4 mm, 15 were 2.7 mm, 7 were 3.5 mm, and 12 were 4.0 mm. Eighteen of the 47 C1-2 transarticular screws were suboptimally placed. Eleven of these misplaced screws were removed and redirected within the same operation because these surgeries benefitted from the use of intraoperative CT; 6 of the 7 remaining suboptimally placed screws were left in place because a second surgery for screw replacement was not warranted. The other suboptimally placed C1-2 screw was replaced during a repeat operation due to failure of fusion. Use of intraoperative CT was invaluable because it enabled the authors to reposition suboptimal C1-2 transarticular screws without necessitating a second operation. CONCLUSIONS Successful craniocervical fusion procedures were achieved using smaller nontraditional titanium screws and plates. Intraoperative CT was a helpful adjunct for confirming and readjusting the trajectory of the screws prior to leaving the operating room, which decreases overall treatment costs and reduces complications.

Baumann angle and radial-ulnar overlap: a radiographic study to control for the angle of the x-ray beam.

Background: Baumanns angle (BA) is the most common radiographic measurement used to assess coronal plane alignment of the distal humerus. However, it can vary greatly based on the x-ray beam angle, which can lead to multiple radiographs causing excessive radiation exposure, cost, and discomfort for the acutely injured child. The lateral capitellohumeral angle is a measure of sagittal plane alignment, and its variability has been reported. In this study, we sought to determine whether there were surrogate measures that could act as internal controls for the angle of the x-ray beam to give an accurate BA. Methods: Elbow radiographs from uninjured children stratified by age into 6 groups were reviewed. BA and lateral capitellohumeral angle as well as several predetermined measurements that could be potential surrogate measures for the angle of the x-ray beam were performed. Statistical significance was found between BA and radial-ulnar overlap (RUO), which was analyzed further and plotted in linear graph fashion. Results: The Pearson correlation coefficient (0.58) between BA and RUO was significant at P=0.001. The average BA was 71±7.2 degrees (1 SD) and the average RUO was 0.34±0.26. The following linear graph equation was obtained to define the relationship between RUO and BA: BA=12.36 (RUO)+67. Further derivation gives us an equation to “correct” BA for a given RUO: corrected BA=measured BA−12.36 (RUO−0.34). Application of this formula lessened the SD of BA from 7.2 to 5.9 degrees and decreased the percentage of BA measurements outside of 1 SD from 30% to 14%. Conclusions: RUO is a reliable surrogate measure to control for the angle of the x-ray beam and improve the reliability when measuring BA that can be easily applied in the clinical setting. Clinical Relevance: The ability to accurately correct the BA based on a given RUO gives the physician the confidence to adequately interpret imperfect radiographs in the emergency room setting and minimize repeat radiographs.

Combined effects of compression and hypotension on nerve root function. A clinical case.

Previous animal experiments suggest that mild compression may increase susceptibility of nerve roots to the effects of hypotension. The authors report the case of a patient with an unstable L2 burst fracture whose motor skills and senses were intact. During fracture reduction and spinal distraction, sensory-evoked potentials were recorded from the epidural space after right and left femoral and tibial nerve stimulation. Induced hypotension was used during the surgery. All responses were normal at the outset of the surgery. With hypotension, a marked drop in the amplitude of the right femoral evoked potential amplitude occurred; left femoral and both tibial responses remained unchanged. Evoked potential changes were reversible with reversal of hypotension. Postoperatively, the patient was neurologically intact. Further analysis revealed a significant correlation between the right femoral evoked potential amplitude and systolic blood pressure (r=0.63, P<0.005), whereas amplitudes of the other responses were not significantly correlated with systolic blood pressure. This report provides clinical evidence to support the hypothesis that hypotension and local compression exert additive adverse effects on nerve root function.

Anaphylactic reaction to tranexamic acid in an adolescent undergoing posterior spinal fusion

Tranexamic acid is an anti‐fibrinolytic agent frequently used in pediatric surgery. Common side effects include nausea, flushing, and headache, but in rare instances, it may produce anaphylaxis; with only one previously reported case in a 72‐year‐old man. We report a case of a delayed anaphylactic reaction in a pediatric patient undergoing posterior spine fusion; and discuss the intraoperative management of the acute event, immunologic confirmation, and subsequent anesthetic approach.

Spine Computed Tomography Radiation Dose Reduction: Protocol Refinement Based on Measurement Variation at Simulated Lower Radiation Acquisitions.

Study Design. Retrospective dose-simulation comparison. Objective. To determine if sufficient detail for preoperative analysis of bony anatomy can be acquired at substantially lower doses than those typically used. Summary of Background Data. Computed tomography (CT) is a preoperative planning tool for spinal surgery. The pediatric population is at risk to express the harmful effects of ionizing radiation. Preoperative CT scans are presently performed at standard pediatric radiation doses not tailored for surgical planning. Methods. We used the validated GE Noise Injection software to retrospectively modify existing spine and chest CT scans from 10 patients to create CT images that simulated a standard dose (100%), 50% dose, and 25% dose scans. 4 orthopedic surgeons and a pediatric radiologist, blinded to dose, measured minimum medial-lateral pedicle width and maximum anterior-posterior bony length along the axis of presumed pedicle screw placement. A total of 90 axial images were generated to create our sample set. Measurements were evaluated for accuracy, precision, and consistency. Results. For any given rater, there was no clinically relevant difference between measurements at the different dose levels and no apparent degradation in precision at the different dose levels. Consistent variation was observed between raters, the likely result of individual differences in measurement approach. Conclusion. Spinal CT scans done for preoperative planning can be performed at 25% of current radiation doses without a loss in surgical planning measurement accuracy or precision. These 25% dose-reduced scans would have average Computed Tomography Dose Index volume dose levels of roughly 1.0 to 2.5 mGy (depending on patient size) and size-specific dose estimates of roughly 2.5 mGy representing a substantial dose savings compared to current practice for many sites. Standardization of consistent landmarks may be useful to further improve inter-rater concordance. Level of Evidence: 2

Early-Onset Spinal Deformity in Skeletal Dysplasias: A Multicenter Study of Growth-Friendly Systems

PURPOSE Severe, early-onset spinal deformity is common in patients with skeletal dysplasia. These deformities often present at young ages and are associated with significant pulmonary dysfunction. The objective of this study is to verify the effectiveness of growth-friendly spinal instrumentation systems in promoting growth in patients with skeletal dysplasia and early-onset kyphoscoliosis. METHODS A retrospective, multicenter comparative cohort study was performed. Twenty-three patients identified to have a skeletal dysplasia (SKD) were evaluated for diagnosis, age at treatment, gender, and type of growing rod construct (spine vs. rib constructs). Patients were matched by age and construct type with similarly treated patients with early-onset scoliosis (CON) without skeletal dysplasia. Radiographic parameters including maximum coronal and sagittal Cobb angle with levels, T1-S1 height, and T1-T12 height were measured. RESULTS T1-T12 (12.8 vs. 15.2 cm, p = .01) and T1-S1 (21.2 vs. 24.5 cm, p = .05) heights were significantly shorter for the SKD group at implantation, and kyphosis tended to be more severe in children with SKD (p = .80 and .07, respectively). Kyphosis did not improve with treatment. Scoliosis improved (p < .01), and ΔT1-T12 and ΔT1-S1 significantly increased in both groups (p < .01). Complication rates were similar between the two groups; however, patients with SKD had more intraoperative monitoring changes and hardware failures (p < .005). CONCLUSION Although patients with SKD start with shorter spine lengths, gains in spine length appear to be comparable to other forms of EOS. Neuromonitoring changes and implant failures are more common in the SKD group. SIGNIFICANCE The effectiveness of growth-friendly techniques in promoting growth in early-onset spinal deformities in patients with skeletal dysplasia has not been previously studied. We report the first comprehensive review of this topic. Growth-friendly techniques are an appropriate treatment option in this patient population.PURPOSE Severe, early-onset spinal deformity is common in patients with skeletal dysplasia. These deformities often present at young ages and are associated with significant pulmonary dysfunction. The objective of this study is to verify the effectiveness of growth-friendly spinal instrumentation systems in promoting growth in patients with skeletal dysplasia and early-onset kyphoscoliosis. METHODS A retrospective, multicenter comparative cohort study was performed. Twenty-three patients identified to have a skeletal dysplasia (SKD) were evaluated for diagnosis, age at treatment, gender, and type of growing rod construct (spine vs. rib constructs). Patients were matched by age and construct type with similarly treated patients with early-onset scoliosis (CON) without skeletal dysplasia. Radiographic parameters including maximum coronal and sagittal Cobb angle with levels, T1-S1 height, and T1-T12 height were measured. RESULTS T1-T12 (12.8 vs. 15.2 cm, p = .01) and T1-S1 (21.2 vs. 24.5 cm, p = .05) heights were significantly shorter for the SKD group at implantation, and kyphosis tended to be more severe in children with SKD (p = .80 and .07, respectively). Kyphosis did not improve with treatment. Scoliosis improved (p < .01), and ΔT1-T12 and ΔT1-S1 significantly increased in both groups (p < .01). Complication rates were similar between the two groups; however, patients with SKD had more intraoperative monitoring changes and hardware failures (p < .005). CONCLUSION Although patients with SKD start with shorter spine lengths, gains in spine length appear to be comparable to other forms of EOS. Neuromonitoring changes and implant failures are more common in the SKD group. SIGNIFICANCE The effectiveness of growth-friendly techniques in promoting growth in early-onset spinal deformities in patients with skeletal dysplasia has not been previously studied. We report the first comprehensive review of this topic. Growth-friendly techniques are an appropriate treatment option in this patient population.

Spontaneous Ankylosis of Occiput to C2 following Closed Traction and Halo Treatment of Atlantoaxial Rotary Fixation.

Study Design Case report. Objective We report a case of spontaneous atlantoaxial rotatory fixation (AARF) presenting 9 months after onset in an 11-year-old boy. Methods This is a retrospective case report of spontaneous ankylosis of occiput to C2 following traction, manipulative reduction, and halo immobilization for refractory atlantoaxial rotatory fixation. Results The patient underwent traction followed by close manual reduction and placement of halo immobilization after 6 months of severe spontaneous-onset AARF that had been refractory to chiropractic manipulation and physical therapy. Imaging demonstrated dislocation of the left C1–C2 facet joint and remodeling changes of the C2 superior facet prior to reduction, followed by near complete reduction of the dislocation after manipulation and halo placement. Symptoms and clinical appearance were satisfactorily improved and the halo vest was removed after 3 months. At late follow-up, computed tomography demonstrated complete bony ankylosis of the occiput to C2. The patient was found to be HLA B27-positive, but he had no family history of ankylosing spondyloarthropathy or other joint symptoms. The underlying reasons for spontaneous fusion of the occiput to C2 could include the traction, HLA-B27-related spondyloarthropathy, or arthropathic changes caused by traction, reduction, the inciting insult, or immobilization. Conclusion When discussing treatment of childhood refractory AARF by traction, closed manipulation, and halo immobilization, the possibility of developing “spontaneous” ankylosis needs to be considered.