Pedicle screw placement safety with the aid of patient-specific guides in a case series of patients with thoracic scoliosis.

PURPOSE: Pedicle screw (PS) placement in thoracic scoliotic deformities can be challenging due to altered vertebral anatomy; malposition can result in severe functional disability or inferior construct stability. Three-dimensional (3D) printed patient-specific guides (PSGs) have been recently used to supplement other PS placement techniques. We conducted a single-center, retrospective observational study to assess the accuracy of PS placement using PSGs in a consecutive case series of pediatric and adult patients with thoracic scoliosis. METHODS: We analyzed the data of patients with thoracic scoliosis who underwent PS placement using 3D-printed PSG as a vertebral cannulation aid between June 2013 and July 2018. PS positions were determined via Gertzbein-Robbins (GR) and Heary classifications on computed tomography images. We determined the concordance of actual and preoperatively planned PS positions and defined the technique learning curve using a receiver-operating characteristic (ROC) curve. RESULTS: We performed 362 thoracic PS placement procedures in 39 consecutive patients. We classified 352 (97.2%), 2 (0.6%), and 8 (2.2%) screws as GR grades 0 (optimal placement), I, and II, respectively. The average instrumented PS entry point offsets on the X- and Y-axes were both 0.8 mm, and the average differences in trajectory between the planned and the actual screw placements on the oblique sagittal and oblique transverse planes were 2.0° and 2.4°, respectively. The learning process was ongoing until the first 12 PSs were placed. CONCLUSIONS: The accuracy of PS placement using patient-specific 3D templates in our case series exceeds the accuracies of established thoracic PS placement techniques.

Electromagnetic navigation system for acetabular component placement in total hip arthroplasty is more precise and accurate than the freehand technique: a randomized, controlled trial with 84 patients.

Background and purpose - The accuracy of conventional navigation systems depends on precise registration of bony landmarks. We investigated the clinical use of electromagnetic navigation (EMN), with a unique device for precise determination of the anterior pelvic plane. Patients and methods - We randomly allocated patients scheduled for total hip arthroplasty into 2 groups of 42 patients each. In the study group, cups were placed at the predetermined target angles (inclination: 42.5°; anteversion: 15°) with the support of EMN. In the control group, cups were placed freehand aiming at the same target angles. Postoperatively the true position of the cup was determined using computed tomography scan of the pelvis. Precision (root mean squared error, RMSE) bias (mean bias error, ME), accuracy, and duration of surgery were compared between the methods. Results - Cup anteversion was more accurate and precise in the navigated group. The ME in the navigated and freehand group was -1.7° (95% CI -2.4 to 1.1) and -4.5° (CI -6.5 to 2.5), respectively. The RMSE in the navigated and freehand group was 2.8° (CI 2.3-3.2) and 8.0° (CI 6.3-9.5), respectively. The inclination was also more precise in the navigated group, with the RMSE in the navigated and freehand group at 4.6° (CI 3.4-5.9) and 6.5° (CI 5.4-7.5), respectively. The accuracy of the inclination and the duration of surgeries were similar between the groups. Interpretation - Cup placement with the help of EMN is more precise than the freehand technique and it does not affect the duration of surgery.

Anterior pushing technique for a broken scalpel blade in lumbar discectomy: a case report.

The presence of broken surgical blades or other surgically uncontrolled sharp and pointed objects in the disc space is a rare but potentially severe complication of posterior lumbar spine procedures. Herein, we report the case of a 59-year-old female patient with a history of lumbar decompression and interspinous process device implantation who underwent an instrumented revision of the lumbosacral junction. During the L5-S1 discectomy, the scalpel blade broke, and the broken fragment could not be retrieved through the posterior approach. With regard to the vascular anatomy, we partially pushed the fragment through the anterior annulus into the retroperitoneal space. In addition, pedicle screws were locked to ensure the stability of the construct. The fractured blade fragment was eventually removed by laparoscopy 1 week after the initial procedure. This experience suggests that the anterior pushing technique with fluoroscopy is an option in rare cases where a broken scalpel blade cannot be reached through the posterior approach. In such cases, computed tomography angiography is recommended.

Slovenian version of the scoliosis research society instrument-22 revised (SRS-22r) in adolescents and adults: Psychometric properties and some implications.

PURPOSE: This study aimed to provide a reliable and valid translation of the Scoliosis Research Society-22 (SRS-22r) questionnaire, compare it with the EQ-5D-5 L questionnaire, and analyse health-related quality of life (HRQoL) of patients with idiopathic scoliosis (IS) in Slovenia in order to potentially improve their rehabilitation processes. METHODS: A matched-case-control study was performed to assess internal consistency reliability, test-retest reliability, concurrent validity, and discriminative validity. The questionnaire was returned by 25 adolescent IS patients, 25 adult IS patients, and 25 healthy controls (87%, 71%, and 100% response rate, respectively). RESULTS: Internal consistency was high for all four scales in the adult IS group, but lower among the adolescent patients. Test-retest reliability of the SRS-22r was high to very high in both patient groups. Correlations between SRS-22r and EQ-5D-5 L were low or close to zero among adolescent patients and moderate or high among adult IS patients. SRS-22r domain scores were statistically significantly different between adult patients and healthy controls. CONCLUSION: The study proved that the Slovenian version of SRS-22r has the psychometric properties needed to measure HRQoL, whereby it appears to be more reliable for adults than adolescents. When used with IS adolescents, SRS-22r is affected by a severe ceiling effect. It could be used for longitudinal follow-up of adult patients after rehabilitation treatment. Additionally, some important issues that adolescents and adults with IS are faced with were identified.

No Significant Radiological Signs of Adult Spinal Deformity Progression after a Mean of 11 Years of Follow-Up Following Harrington Rod Instrumentation Removal and Watchful Waiting.

The study aimed to assess long-term radiological outcomes in patients from our institution who were primarily treated for adolescent idiopathic scoliosis with surgical correction using Harrington rod (HR) instrumentation, and afterward with watchful waiting of residual spinal deformity after HR removal, whereby no patient consented to spinal deformity correction. A single-institution case series of 12 patients was retrospectively evaluated. Preoperative and most recent post-instrumentation removal radiographic measurements were compared, along with baseline characteristics. The average age of patients (all females) at the time of HR instrumentation removal was 38 ± 10 years (median 40, range 19-54). The mean follow-up from the HR instrumentation implantation to the HR instrumentation removal was 21 ± 10 years (median 25, range 2-37), with a further mean of 11 ± 10 years (median 7, range 2-36) of follow-up following HR instrumentation removal and watchful waiting. No significant change in radiological parameters was observed: LL (p = 0.504), TK (p = 0.164), PT (p = 0.165), SS (p = 0.129), PI (p = 0.174), PI-LL (p = 0.291), SVA (p = 0.233), C7-CSVL (p = 0.387), SSA (p = 0.894), TPA (p = 0.121), and coronal Cobb angle (proximal (p = 0.538), main thoracic (p = 0.136), and lumbar (p = 0.413)). No significant change in coronal or sagittal parameters was observed in this single-institution long-term radiological outcome study of adults following HR instrumentation removal and watchful waiting of residual spinal deformity.

Fatal Fulminant Fat Embolism Syndrome in Adult Spine Deformity Surgery: A Case Report.

CASE: A 68-year-old woman was scheduled to undergo elective correction of coronal spinal malalignment after a previous lumbar instrumented fusion. In the final stages of the operation, the patient became hemodynamically unstable. Her systemic condition worsened subsequently, leading to cardiac arrest followed by unsuccessful resuscitation. An autopsy revealed a massive fat embolism in the lungs. CONCLUSIONS: The diagnosis of fat embolism syndrome (FES) is clinical, and treatment is supportive, with no clinical or investigative criteria that can facilitate diagnosis in a patient under general anesthesia. This is the first description of FES in adult spinal deformity surgery.

Malpositioned pedicle screw in spine deformity surgery endangering the aorta: report of two cases, review of literature, and proposed management algorithm.

STUDY DESIGN: Case reports and review of the literature with a proposed management algorithm. OBJECTIVES: To report two cases of a potential vascular complication due to an incorrectly placed pedicle screw (PS) during spine deformity surgery. Relevant literature regarding the management of vascular complications is reviewed, and an evidence-based management algorithm is proposed. Aortic lesions represent a rare but potentially life-threatening complications with spine deformity and revision surgery, significantly increasing the risk. A management algorithm for an aortic lesion in the case of a malpositioned PS has not yet been published. METHODS: Case 1: An 18-year-old female with proximal thoracic spinal non-instrumented fusion underwent a revision corrective procedure due to a progressive right-sided thoracolumbar compensatory curve. However, postoperative computed tomography (CT) performed to evaluate the position of the PS revealed malposition of the left T9 PS, which was abutting the descending aorta with CT angiography excluding the perforation of the aorta. Case 2: A 17-year-old male was scheduled for correction of Lenke 3-C-N adolescent idiopathic scoliosis. Postoperative routine evaluation with low-dose CT revealed a left T9 PS paravertebral malposition, and subsequent CTA demonstrated that the thread of the PS was in contact with the descending thoracic aorta and an unlikely hemodynamically significant vessel injury. RESULTS: Successful removal of both malpositioned PS was performed. In the first case, a cardiovascular surgeon attended the operation if an urgent thoracotomy was needed, and in the second case, additional video-assisted thoracoscopic control of the aorta was performed during PS removal. CONCLUSIONS: Preoperative imaging in spinal surgery is essential to avoid major vascular and other complications when placing PS, especially in thoracic deformities. When a potential major vessel complication emerges, an interdisciplinary approach and an appropriate management algorithm are mandatory to make the best clinical decisions. LEVEL OF EVIDENCE: 4.

Variability Analysis of Manual and Computer-Assisted Preoperative Thoracic Pedicle Screw Placement Planning.

STUDY DESIGN: A comparison among preoperative pedicle screw placement plans, obtained from computed tomography (CT) images manually by two spine surgeons and automatically by a computer-assisted method. OBJECTIVE: To analyze and compare the manual and computer-assisted approach to pedicle screw placement planning in terms of the inter- and intraobserver variability. SUMMARY OF BACKGROUND DATA: Several methods for computer-assisted pedicle screw placement planning have been proposed; however, a systematic variability analysis against manual planning has not been performed yet. METHODS: For 256 pedicle screws, preoperative placement plans were determined manually by two experienced spine surgeons, each independently performing two sets of measurements by using a dedicated software for surgery planning. For the same 256 pedicle screws, preoperative placement plans were also obtained automatically by a computer-assisted method that was based on modeling of the vertebral structures in 3D, which were used to determine the pedicle screw size and insertion trajectory by maximizing its fastening strength through the underlying bone mineral density. RESULTS: A total of 1024 manually (2 observers × 2 sets × 256 screws) and 256 automatically (1 computer-assisted method × 256 screws) determined preoperative pedicle screw placement plans were obtained and compared in terms of the inter- and intraobserver variability. A large difference was observed for the pedicle screw sagittal inclination that was, in terms of the mean absolute difference and the corresponding standard deviation, equal to 18.3°â€Š±â€Š7.6° and 12.3°â€Š±â€Š6.5°, respectively for the intraobserver variability of the second observer and for the interobserver variability between the first observer and the computer-assisted method. CONCLUSION: The interobserver variability among the observers and the computer-assisted method is within the intraobserver variability of each observer, which indicates on the potential use of the computer-assisted approach as a useful tool for spine surgery that can be adapted according to the preferences of the surgeon. LEVEL OF EVIDENCE: 3.