The fate of the malrotated elbow supracondylar fractures in children: is varus really a problem?

PURPOSE: To evaluate the functional and cosmetic effects of elbow supracondylar fractures (SCF) in children with residual rotational deformity. METHODS: Retrospective review cohort of patients with evidence of malrotation after treatment for SCF. An analysis of the postoperative X-ray of 305 consecutive SCF type 3 treated surgically during five years identified 46 elbows with rotational deformity that fulfilled the selection criteria and were recalled for review; only 27 patients agreed to participate. Patients were evaluated clinically and radiographically. Clinically, the elbow and shoulder ROM were assessed. The postoperative fracture rotation (PFR) was radiologically measured using the Berdis method. Results were categorized according to Flynn criteria, and functional outcomes were evaluated with the QuickDASH questionnaire. On final assessment, a radiograph of both elbows was obtained, and measures were compared. Descriptive analysis was made calculating median, range, proportions, and confidence intervals. Non-parametric tests were used to test the association between variables. RESULTS: The group had a median age of four years and a median follow-up of 52 months. Shoulder rotation was asymmetrical in 13 patients; six patients presented a change on carrying angle > 5° (4 varus/2 valgus). The higher the residual rotation, the higher the chances of an altered shoulder rotation (for each degree of PFR, the shoulder rotation was changed to 0.4°). However, there was a low correlation between the amount of rotation and the final carrying angle (r = 0.37). According to Flynn's criteria, over 95% had excellent or good results. CONCLUSION: There was a weak correlation between varus and rotational malalignment. Patients with moderate residual malrotation could be expected to have a good outcome even if some shoulder rotation changes persist.

Intra-articular Radial Head Fractures: A Deceptive Type of Injury.

BACKGROUND: Isolated intra-articular radial head (IARH) fractures in skeletally immature patients represent a rare injury. Despite their initial benign radiologic appearance, these fractures are at risk for progressive radial head subluxation and may end with degenerative irreversible changes of the radiocapitellar joint. The aim of this study is to highlight the seriousness of these injuries and the importance of early diagnosis and a proper follow-up to achieve optimal outcomes. METHODS: We retrospectively reviewed 6 patients with IARH fractures treated at our institution between 2011 and 2016. All patients presented with Salter-Harris types III or IV fracture. Five of 6 fractures were initially undisplaced. Treatment, clinical, and radiographic results were analyzed. Patients were divided into 2 groups according to treatment: patients included in group A were treated conservatively, whereas patients of group B were treated with early surgery. The final functional outcome was assessed using the Oxford Elbow Score (OES). The Broberg-Morrey classification was used for the radiographic results. RESULTS: Group A included 3 patients (average age, 11±2 y). They developed an initially missed posterior subluxation of the radiocapitellar joint that caused to all of them a painful elbow and limited range of motion (ROM). Despite rescue surgery, they all presented with limited ROM at the final follow-up, although no functional limitations (OES, 46.3±2.9). The radiographs showed early degenerative changes. Group B included 3 patients (average age, 11±1 y) all treated surgically within 1 week from the injury. They showed no limitation of ROM and good functional (OES, 47.7) and radiologic outcomes. CONCLUSIONS: IARH fractures in skeletally immature children are deceptive injuries which are often underestimated. Surgeons should be aware of these fractures, especially when a discrepancy between the clinical signs and symptoms, and the radiologic appearance exists, as this may be the only red flag that allows their identification in the acute setting. An early and accurate diagnosis followed by prompt and more aggressive treatment when necessary is mandatory for successful results. LEVEL OF EVIDENCE: Level IV-case series.

Cervical and thoracic sagittal misalignment after surgery for adolescent idiopathic scoliosis: a comparative study of all pedicle screws versus hybrid instrumentation.

STUDY DESIGN: A comparative study of 2 cohort series of surgically treated patients with adolescent idiopathic scoliosis (AIS) who were retrospectively analyzed, with level III evidence. OBJECTIVE: To compare the effect on the cervical sagittal balance of 2 AIS correction constructs, namely, all pedicle screws and hybrid instrumentation using hooks and pedicle screws. SUMMARY OF BACKGROUND DATA: An inverse relationship between cervical and thoracic kyphosis in AIS has been found in pediatric patients after concave derotation using hybrid constructs with pedicle screws and hooks. METHODS: Two series of 25 nonconsecutive patients with Lenke type-I AIS who underwent spinal fusion were retrospectively reviewed. In 1 series, the patients were treated with all thoracic pedicle screw constructs. In the other series, the correction was achieved by using hybrid constructs. Preoperative and 2-year follow-up radiographical examinations were evaluated, measuring the following parameters: C2-C7 sagittal angle, displacement of C2-C7 plumb line, T1 sagittal tilt, T1-T5 and T5-T12 sagittal profile, and C7-S1 global sagittal balance. RESULTS: In both groups, there was a lordotic effect on the T5-T12 kyphosis after surgery, with an average loss of 6.1° for hybrid and 7.7° for pedicle screws. When the postoperative data were compared, the intergroup differences were found only in the sagittal C2-C7 Cobb angle, showing a mean kyphotic trend (-5.2°) in the pedicle screws group compared with a mean lordotic trend (1.8°) in the hybrid group (P < 0.05). In both techniques, the patients with upper-instrumented vertebra at T4 or below showed a lordotic effect that was more evident in the hybrid constructs (+9.4° ± 11.3 vs. +0.3° ± 11.4). In those with the upper-instrumented vertebra at T3 or higher levels, both techniques had a kyphotic effect that was more severe in the patients of the pedicle screws group (-7.0° ± 12.6 vs. -2.8° ± 10.5). CONCLUSION: Independent of the surgical technique used, the cervical spine had a tendency to decompensate and acquire a kyphotic sagittal profile. Constructs based on all pedicle screws have a stronger hypokyphotic effect on the thoracic spine, with a predisposition to greater decompensation of the cervical spine. Kyphotic changes in the C2-C7 sagittal alignment induced by scoliosis correction are correlated with the level of the upper-instrumented vertebra.

Influence of hypotension and nerve root section on the ability to mobilize the spinal cord during spine surgery. An experimental study in a pig model.

BACKGROUND CONTEXT: The correction of severe spinal deformities by an isolated posterior approach often involves cord manipulation together with hypotensive anesthesia. To date, the efficiency of methods to increase the tolerance of the cord to displacement and the influence of hypotension on this tolerance is yet to be assessed. PURPOSE: The objective of this study was to determine the limits of cord displacement before the disappearance of neurophysiologic signals. The influence of the type of force applied, the section of the roots, and the induced hypotension on the cord's tolerance to displacement was also assessed. STUDY DESIGN: Experimental study using a domestic pig model. OUTCOME MEASURES: Successive records of cord-to-cord motor evoked potentials were obtained during displacement maneuvers. Displacing forces were released immediately after the absence of neurophysiologic signals. METHODS: Surgical procedures were performed under conventional general anesthesia. The spinal cord and nerve roots from T6 to T10 levels were exposed by excision of the posterior elements, allowing for free cord movement. Three groups were established according to the method of spinal cord displacement: the separation (Group 1, n=5), the root stump pull (Group 2, n=5), and the torsion groups (Group 3, n=5). An electromechanical external device was used to apply the displacing forces. The three displacement tests were repeated after sectioning the adjacent nerve roots. The experiments were first carried out under normotension and afterward under induced hypotension. RESULTS: In Group 1, evoked potential disappeared with a displacement of 10.1±1.6 mm with unharmed roots and 15.3±4.7 mm after the sectioning of four adjacent roots (p<.01). After induced hypotension, potentials were lost at 4.0±1.2 mm (p<.01). In Group 2, the absence of potentials occurred at 20.0±4.3 mm and increased to 23.5±2.1 mm (p<.05) after cutting the two contralateral roots. Under hypotensive conditions, the loss of neurophysiologic signals was detected at 5.3±1.2 mm (p<.01). In Group 3, the cord allowed torsion of 95.3±.2° that increased to 112.4±7.1° if the contralateral roots were cut. Under hypotension, the loss of potentials was found at 20±6.2° (p<.01). CONCLUSIONS: In this experimental model, it was possible to displace the thoracic spinal cord by a distance superior to the spinal cord width without suffering neurophysiologic changes. The limits of cord displacement increase when the adjacent nerve roots are sacrificed. Induced hypotension had a dramatic effect on the tolerance of the spinal cord for displacement. This work has an important clinical significance because induced hypotension during specific spine surgery procedures requiring spinal cord manipulation in humans may increase the risk of neurologic spinal cord injury.

Safe pedicle screw placement in thoracic scoliotic curves using t-EMG: stimulation threshold variability at concavity and convexity in apex segments.

STUDY DESIGN: A cross-sectional study of nonconsecutive cases (level III evidence). OBJECTIVE: In a series of young patients with thoracic scoliosis who were treated with pedicle screw constructs, data obtained from triggered electromyography (t-EMG) screw stimulation and postoperative computed tomographic scans were matched to find different threshold limits for the safe placement of pedicle screws at the concavity (CC) and convexity (CV) of the scoliotic curves. The influence of the distance from the medial pedicle cortex to the spinal cord on t-EMG threshold intensity was also investigated at the apex segment. SUMMARY OF BACKGROUND DATA: Whether the t-EMG stimulation threshold depends on pedicle bony integrity or on the distance to neural tissue remains elusive. Studying pedicle screws at the CC and CV at the apex segments of scoliotic curves is a good model to address this issue because the spinal cord is displaced to the CC in these patients. METHODS: A total of 23 patients who underwent posterior fusions using 358 pedicle thoracic screws were reviewed. All patients presented main thoracic scoliosis, with a mean Cobb angle of 58.3 degrees (range, 46-87 degrees). Accuracy of the screw placement was tested at surgery by the t-EMG technique. During surgery, 8 screws placed at the CC showed t-EMG threshold values below 7 mA and were carefully removed. Another 25 screws disclosed stimulation thresholds within the range of 7 to 12 mA. After checking the screw positions by intraoperative fluoroscopy, 15 screws were removed because of clear signs of malpositioning. Every patient underwent a preoperative magnetic resonance imaging examination, in which the distances from the spinal cord to the pedicles of the concave and convex sides at 3 apex vertebrae were measured. Postoperative computed tomographic scans were used in all patients to detect screw malpositioning of the final 335 screws. RESULTS: According to postoperative computed tomographic scans, 44 screws (13.1%) showed different malpositions: 40 screws (11.9%) perforated the medial pedicle wall, but only 11 screws (3.2%) were completely inside the spinal canal. If we considered the 23 screws removed during surgery, the true rate of misplaced screws increased to 18.7%. In those screws that preserved the pedicle cortex (well-positioned screws), EMG thresholds from the CC showed statistically significantly lower values than those registered at the CV of the deformity (21.1 ± 8.2 vs 23.9 ± 7.7 mA, P < 0.01). In the concave side, t-EMG threshold values under 8 mA should be unacceptable because they correspond to screw malpositioning. Threshold values above 14 mA indicate an accurate intrapedicular position with certainty. At the convex side, threshold values below 11 mA always indicate screw malpositioning, and values above 19 mA imply accurate screw placement. At the 3 apex vertebrae, the average pedicle-spinal cord distance was 2.2 ± 0.7 mm at the concave side and 9.8 ± 4.3 mm at the convex side (P < 0.001). In well-positioned screws, a correlation between pedicle-dural sac distance and t-EMG threshold values was found at the concave side only (Pearson r = 0.467, P < 0.05). None of the patients with misplaced screws showed postoperative neurological impairment. CONCLUSION: Independent of the screw position, average t-EMG thresholds were always higher at the CV in the apex and above the apex regions, presuming that the distance from the pedicle to the spinal cord plays an important role in electrical transmission. The t-EMG technique has low sensitivity to predict screw malpositioning and cannot discriminate between medial cortex breakages and complete invasion of the spinal canal.

Comparing the clinical and radiological outcomes of pedicular transvertebral screw fixation of the lumbosacral spine in spondylolisthesis versus unilateral transforaminal lumbar interbody fusion (TLIF) with posterior fixation using anterior cages.

STUDY DESIGN: This study retrospectively compares the clinical and radiologic outcomes of unilateral transforaminal lumbar interbody fusion (TLIF) with those of transvertebral screw fixation of the lumbosacral spine in high-grade spondylolisthesis. OBJECTIVE: To examine the outcome and perioperative complications of unilateral TLIF and compare those results with Transvertebral Screw Fixation in the treatment of high-grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: High-grade spondylolisthesis has been associated with a high complication and failure rate regardless of the method of treatment. We compare 2 techniques to improve success rates. METHODS: Forty patients were divided into 2 groups: group A, unilateral TLIF, and group B, transacral screws. The mean age was 33 years (range, 19-48 years), and the mean follow-up was 35 months (range, 24-48 months). The mean grade of spondylolisthesis measured by Meyerding grading was 3.6 (range, 3-5). A Scoliosis Research Society outcome score was obtained on all patients. Fusion was determined by both radiograph and computed tomography scan. RESULTS: Group A: 100% fusion. The slip angle improved from 38.6 degrees (range, 24-78 degrees ) before surgery to 23.8 degrees (range, 12-38 degrees ) after surgery. Group B: 95% of patients evidenced solid fusion by the 6-month follow-up. The slip angle, improved from 38.2 degrees (range, 22-78 degrees ) before surgery to 23 degrees (range, 9-36 degrees ) after surgery. There was no significant improvement in the percentage slip or the sacral inclination in any of the groups. COMPLICATIONS: A: 7 unintended durotomies and 3 wound infections. B: 1 unintended durotomy, 1 pseudarthrosis, 2 wound infections, and 1 implant failure. There were no neurologic complications in any of the groups. The Scoliosis Research Society outcome instrument demonstrated good postoperative pain control, function, self-image, and satisfaction in both groups. CONCLUSION: No significant differences in radiologic and clinical outcome were found, in either group. Both procedures appear to be safe and effective surgically and radiographically.

Using triggered electromyographic threshold in the intercostal muscles to evaluate the accuracy of upper thoracic pedicle screw placement (T3-T6).

STUDY DESIGN: A prospective clinical study of high thoracic pedicle screws monitored with triggered electromyographic (EMG) testing. OBJECTIVE: To evaluate the sensitivity of recording intercostal muscle potentials to assess upper thoracic screw placement. SUMMARY OF BACKGROUND DATA: Triggered EMG testing from rectus muscle recordings, which are innervated from T6 to T12, has identified medially placed thoracic pedicle screws. No clinical study has correlated an identical technique with the intercostal muscle for upper pedicle screws placed in the upper thoracic spine (T3-T6). METHODS: A total of 311 high thoracic screws were placed in 50 consecutive patients. Screws were placed from T3 to T6 and were evaluated using an ascending method of stimulation until a compound muscle action potential was obtained from the intercostal muscles. Screw position was then evaluated using computed tomography and results were compared with evoked EMG threshold values. RESULTS: Fifteen screws (5%) showed penetration on postoperative computed tomography scans. Eleven screws showed medial cortical breakthrough (3.6%), 6 had stimulation thresholds 20 mA. Of the 296 screws with thresholds between 6 and 20 mA, 285 (91%) were within the vertebra. No postoperative neurologic complications were noted in any of the 50 patients. CONCLUSION: In this series, cortical violation is highly unlikely in patients whose stimulation threshold lies between 6 and 20 mA with values 60% to 65% decreased from the mean (98% negative predictive value). Although verification of screw placement should not depend solely on stimulation thresholds, pedicle screw stimulation provides rapid and useful intraoperative information on screw placement during procedures involving the use of thoracic pedicle screws.