Proximal foundation anchor variations and their correlation with unplanned return to the operating room (UPROR) in children with EOS treated with magnetically controlled growing rods (MCGR).

INTRODUCTION: The evolution of MCGR technique has led to modifications in the configuration of the proximal construct to decrease the incidence of implant-related complications (IRC) and revision surgeries. However, there is no data characterizing the performance of the most used configurations reducing the risk of complications. METHODS: 487 patients were identified from an international multicenter EOS database. INCLUSION CRITERIA: EOS patients, primary dual MCGR, complete radiographs, and minimum of 2-year follow-up. 76 patients had incomplete X-rays, 5 had apical fusions, and 18 had inconclusive complications, leaving 388 patients for review. A digital spine template was created to document UIV; number of levels; number, type, and location of anchors; as well as implant configuration. First available postoperative and latest follow-up radiographs were reviewed by two senior surgeons and two spine fellows. UPROR due to IRC was defined as any change in proximal anchors between the postoperative and final follow-up radiographs. RESULTS: The most common proximal construct configuration: UIV at T2 (50.0%) with 17.5% UPROR, followed by T3 (34.0%) with 12.1% UPROR; number of levels was three (57.1%) with 16.8% UPROR and two (26.0%) with 17.0% UPROR; number of proximal anchors was six (49.9%) with 14.1% UPROR and four (27.0%) with 18.3% UPROR. The most common anchors were all screws (42.0%) with 9.9% UPROR, and all hooks (26.4%) with 31.4% UPROR (P < 0.001). The construct with the lowest rate of UPROR was a UIV at T2, with six anchors (all screws) across three levels (42 cases), with 0% UPROR. Other construct combinations that yielded 0% UPROR rates were UIV of T3, six anchors (all screws) across three levels (25 cases), and a UIV of T3 with six anchors (screws and hooks) across three3 levels (9 cases). CONCLUSION: Proximal anchor configuration impacts the incidence of UPROR due to IRC in MCGR. UIV at T2 and T3 compared to T4, and the use of all screws or combination of screws and hooks compared to all hooks were associated with a lower UPROR rate. The most common construct configuration was T2 UIV, three levels, six anchors, and all screws. The use of a combination of six anchors (screws or screws and hooks) across three levels with a UIV at T2 or T3 was associated with a lower UPROR rate. Additional research is needed to further evaluate the variables contributing to configuration selection and their association with IRC.

Thoracolumbar and Lumbar Posterior Vertebral Resection for the Treatment of Rigid Congenital Spinal Deformities in Pediatric Patients: A Long-Term Follow-up Study.

Objective: We sought to determine whether a posterior vertebral resection on congenital deformities of thoracolumbar and lumbar vertebrae leads to more complications and provides less correction. Methods: Twenty-three patients underwent a posterior vertebral resection for a rigid congenital spinal deformity, which included scoliosis (13 patients), kyphoscoliosis (6 patients), and pure kyphosis (4 patients). The surgeries involved removing 1 to 2 vertebrae using multiaxial pedicle screws in all but 2 of the patients. All surgeries were performed under intraoperative spinal cord monitoring. Thoracic curve, lumbar lordosis, focal kyphosis, shift, and sagittal vertical axis were collected at baseline and during the last follow-up (taking place after at least 3 years) and were then statistically analyzed. Results: The major curve correction was about 55% in cases of scoliosis, with focal kyphosis improving from 54.3 ± 19.1 degrees to 21.3 ± 15 degrees. Two patients experienced intraoperative neuromonitoring changes, with data returning to baseline without any surgical intervention. Sensory or motor palsy after the surgery was not reported in patients.Despite improving sagittal or coronal deformities, 8 patients experienced excessive sagittal decompensation during follow-up, 1 of whom underwent revision surgery. Sagittal decompensation was by far the most common complication. Larger kyphoscoliosis or focal kyphosis angles were preoperative risk factors for postoperative sagittal imbalance (P value < 0.05). Conclusions: Using a lumbar or thoracolumbar posterior vertebral resection enables surgeons to correct rigid curves in the pediatric population without major risk to nerve roots. The primary complications would be sagittal decompensation and the likelihood of undercorrection, which requires mindful addressing during the preoperative planning stages.

In vivo distraction force and length measurements of growing rods: which factors influence the ability to lengthen?

STUDY DESIGN: Prospective, intraoperative force measurement in consecutive lengthening procedures in a series of growing-rod patients undergoing lengthening. OBJECTIVE: The purpose of this study was to measure the forces and amount of distraction over time in early onset scoliosis patients treated with growing rods. SUMMARY OF BACKGROUND DATA: Growing rods are one of the current techniques used in the treatment of early onset scoliosis, and the goal of the growing-rod technique is to achieve deformity correction, maintaining spinal growth at the same time. Gradual stiffening or spontaneous fusion of the spine can interfere with the ability to lengthen. In addition, diminished acquired length with serial distraction are common observations and need to be evaluated and quantified. METHODS: Distraction forces were measured prospectively during 60 consecutive lengthening procedures in 26 patients. All patients had single submuscular rod constructs with side-to-side connectors. For each measurement, output from a transducer on a dedicated pair of distraction calipers was recorded at zero load status and the force was then recorded at every 1 mm lengthening; length was obtained at each event and was recorded in millimeters. RESULTS: The force required to distract the spine doubled at the 5th lengthening procedure (mean 368 N ± 54 N), and the distraction force was significantly higher at the fifth lengthening compared with the previous lengthening (P <0.01). Mean length achieved at each distraction decreased over time such that by the fifth lengthening, consistently 8 mm or less was achieved. CONCLUSION: Distraction forces increase significantly after repeated lengthening of growing-rod constructs, and the length obtained at each procedure exhibits a decreasing trend.

Anterior instrumentation and correction of congenital spinal deformities under age of four without hemivertebrectomy: a new alternative.

STUDY DESIGN: Retrospective clinical and radiologic evaluation of a single-stage partial corpectomy of the hemivertebra with anterior instrumentation and simultaneous posterior noninstrumented fusion. OBJECTIVE: To determine the safety and efficacy of a new technique in the management of progressive congenital spinal deformities due to failure of formation in the very young age. SUMMARY OF BACKGROUND DATA: Several techniques have been reported for the surgical treatment of young children with congenital spinal deformities. There have been concerns regarding epidural bleeding, neurologic complications, pedicle screws placement, implant failure, and prominence of posterior constructs in this very young age group. A single-stage partial corpectomy of the hemivertebra with anterior instrumentation and simultaneous posterior noninstrumented fusion can offer a new alternative which can avoid these concerns. METHODS: Twelve patients with progressive congenital spinal deformities due to failure of formation were retrospectively reviewed after adopting the above mentioned technique. All patients included in the study presented with a single hemivertebra. The mean age at time of surgery was 2 years 7 months (range, 1 year and 9 months to 3 years and 10 months). The average follow-up period was 3 years and 1 month (range, 2 years to 4 years and 5 months). RESULTS: There were no cases of intra or postoperative neurologic or implant related complications. There was 1 superficial infection. All patients showed solid radiologic fusion. The mean scoliosis angle improved from 48.3° (range, 34°-58°) preoperative to 17.2° (range, 11°-25°). The mean angle of kyphosis improved from 23.2° (range, 16°-57°) before surgery to 11.7° (range, 4°-16°). CONCLUSION: A single-stage partial corpectomy of the hemivertebra with anterior instrumentation and simultaneous posterior noninstrumented fusion offers a safe alternative method in treating patients with congenital hemivertebra under the age of 4 years.

All pedicle screw instrumentation for Scheuermann's kyphosis correction: is it worth it?

BACKGROUND CONTEXT: Scheuermann's kyphosis has long been treated by a two-staged fusion and instrumentation with a hybrid construct using hooks, pedicle screws, and sublaminar wires. Recent interest in all pedicle screw constructs led to its use in the treatment of Scheuermann's kyphosis. Evaluation of this newly described application is needed. PURPOSE: To compare the results of segmental all pedicle screw constructs versus two-staged hybrid instrumentation in patients with Scheuermann's kyphosis analyzing the amount of correction and incidence of complications. STUDY DESIGN: Retrospective case series reporting on two groups of patients with Scheuermann's kyphosis treated with single-staged all pedicle screws technique versus two-staged anterior release and posterior hybrid instrumentation followed-up for a minimum of 2 years. PATIENT SAMPLE: The study included 33 patients divided into two groups. The average age was 15 years+9 months and 16 years+8 months, respectively. The average preoperative dorsal kyphosis was 85.5 degrees (Group 1) and 79.8 degrees (Group 2). OUTCOME MEASURES: The deformity was measured by Cobb's method preoperatively, postoperatively, and at final follow-up. Operative time and blood loss were also measured and recorded. The results of the Scoliosis Research Society (SRS)-30 questionnaire were also reviewed. METHODS: The study included 16 patients who underwent a single-staged correction by segmental all pedicle screw constructs and multiple-level posterior osteotomies (Group 1) and 17 who underwent a two-staged fusion and instrumentation with a hybrid construct (Group 2). RESULTS: Both groups were followed for a minimum of 2 years. The deformity correction of Group 1 had an average of 52.2% postoperatively with 2.4% loss at final follow-up in comparison to Group 2 where the correction was 48.7% postoperatively with 3.1% loss at final follow-up. The operative time was considerably less in Group 1 with an average of 215 minutes than Group 2 with an average of 315 minutes. The average blood loss was 620cc in Group 1 and 910cc in Group 2. The SRS-30 questionnaire in Group 1 averaged 134 and in Group 2 averaged 120. CONCLUSIONS: The use of multiple-level all pedicle screws technique allowed a rigid anchor for posterior correction of the deformity with less operative time, blood loss, and hospital stay without the need for anterior release. A better correction was achieved and preserved with the use of all pedicle screw constructs. This technique is a useful modality in the treatment of Scheuermann's kyphosis.