Arthroscopic Fixation of Knee Femoral Condyle Osteochondritis Dissecans Fragment With Bone Marrow Aspirate Concentrate.

This article reviews a technique for arthroscopic fixation of an osteochondritis dissecans fragment with bone marrow aspirate concentrate augmentation. This technique involves safe harvest of bone marrow arthroscopically from the intercondylar notch, proper preparation and debridement of the parent bone, reduction of the progeny osteochondritis dissecans fragment, insertion of the bone marrow aspirate concentrate, and placement of multiple headless compression screws for fixation.

Change in Sagittal Plane Alignment Following Surgery for Scheuermann's Kyphosis.

STUDY DESIGN: Retrospective comparative study. OBJECTIVE: To evaluate changes in sagittal plane alignment in patients with Scheuermann's kyphosis after spinal fusion. SUMMARY OF BACKGROUND DATA: Although surgery is commonly undertaken in patients with severe Scheuermann's kyphosis for deformity correction, there are limited data regarding the response of spinopelvic parameters and sagittal plane alignment of the spine to surgical treatment. METHODS: Eighteen consecutive surgical Scheuermann's kyphosis patients were retrospectively reviewed (mean preoperative kyphosis, 76°). Full-length spine films were evaluated for maximal sagittal Cobb angle, thoracic kyphosis, cervical and lumbar lordosis, pelvic parameters, and sagittal plane alignment. Findings were compared with reported literature values in normal patients. RESULTS: After surgery, thoracic kyphosis improved significantly, with mean maximum kyphosis improving from 76° to 56° (p = .001). Preoperative cervical lordosis was increased compared with reported normal adolescent values (-35° vs. -5°) and did not significantly change after surgery. Lumbar lordosis decreased significantly after surgery, from -77° to -57° (p = .023). No change was noted in pelvic tilt, sacral slope, or pelvic incidence. Furthermore, there was little improvement in sagittal plane alignment. Preoperatively, 12 of the 18 patients had deviation in sagittal plane alignment greater than 2 cm (5 positive and 7 negative); postoperatively, 11 patients had persistent sagittal imbalance (6 positive and 5 negative). Five patients were noted to have proximal junctional kyphosis and 3 underwent revision surgery for malpositioned screw (1) and loss of distal fixation (2). CONCLUSIONS: Surgical management of Scheuermann's kyphosis resulted in normalization of thoracic kyphosis and lumbar lordosis. Compared with reported values in unaffected adolescents, cervical lordosis remained increased and most patients had residual sagittal plane imbalance greater than 2 cm on imaging.

Spinal stenosis frequent in children with multiple hereditary exostoses.

PURPOSE: Children with multiple hereditary exostoses (MHE) have numerous osteochondromas, with the most prominent lesions typically over the appendicular skeleton. A recent report noted a high rate of intracanal lesions in this patient population and recommended preventative spinal screening with magnetic resonance imaging (MRI) or computed tomography (CT). We sought to evaluate the prevalence of spinal stenosis from intracanal osteochondromas at our pediatric orthopedic center in order to evaluate if routine screening is warranted. METHODS: All pediatric patients treated for MHE were retrospectively identified. Records were reviewed to determine demographics, previous orthopedic surgery, and indication and results of axial spine imaging (CT or MRI). Imaging studies were reviewed to evaluate the presence of intracanal and compressive spinal lesions. RESULTS: Between 1990 and 2011, axial imaging was performed in nine patients with MHE due to concerns of pain, weakness, and/or dizziness. These patients had moderate disease involvement, with a mean of 4.9 previous orthopedic surgeries to address skeletal osteochondromas. Two patients with MHE had cervical spinal stenosis secondary to intracanal osteochondromas. Both children successfully underwent spinal decompression. Thus, of our MHE population undergoing axial imaging, 22 % were noted to have intracanal lesions. CONCLUSIONS: Our experience reveals a >20 % rate of compressive intracanal osteochondromas in MHE patients undergoing spinal imaging. These two patients represent 5 % of the MHE patients treated at our center. These lesions may be slow growing, and significant consequences can occur if not identified promptly. Thus, we confer that routine axial screening of the spinal canal may be warranted in these children.

The accuracy of navigation and 3D image-guided placement for the placement of pedicle screws in congenital spine deformity.

BACKGROUND: Treatment of congenital spine deformity has high surgical risk due to abnormal anatomy and dysmorphic pedicles. We hypothesized that an image-guided navigation system would result in a low rate of screw revision due to malposition. METHODS: From 2007 to 2010, 142 screws were placed in 14 consecutive patients with congenital spine deformity using an intraoperative computer tomography (CT) (O-arm) and image-guided navigation system (Stealth). Mean age was 8.8 years (range, 1 to 18 y). Deformities included scoliosis (12), kyphosis (1), and spinal dysgenesis (1). Screws were placed from T2 to S1. An intraoperative CT verified screw position. Need for intraoperative screw revision is the primary outcome measure. RESULTS: Of the 142 screws placed, 1 required revision intraoperatively due to malposition (99.3% screw accuracy rate). The screw was at L3 and was successfully redirected. There were no complications due to screw malposition. This navigated congenital screw accuracy rate (99.3%) is higher than the 94.9% accuracy rate reported for non-navigated screws in all children undergoing pedicle screw fixation in a recent systematic literature review and higher than the reported 96.4% accuracy rate for navigated pedicle screws in children. Kosmopoulos and colleagues found a lower accuracy rate (86.6%) in adult non-navigated screws (P<0.0001) and adult navigated screws (93.7%). Of note, 9 pedicles were noted on navigation to be absent. Despite the goal of bilateral screw placement at each fusion level, 31 of 173 pedicles were left unfilled due to technical impossibility based on intraoperative CT imaging. This represents an 18% screw dropout rate. CONCLUSIONS: CT-guided navigation resulted in the successful placement of 142 pedicle screws in patients with congenital deformity and altered anatomy, which represents a 99.3% screw accuracy rate. This is comparable with the screw accuracy rate of 93.7% reported for adult navigated pedicle screws. Further, navigation prevented attempts of screw placement at levels with absent or impassable pedicles. Image-guided navigation and intraoperative CT are valuable tools for the safe placement of pedicle screws in patients with significant congenital spine deformity and altered anatomy. LEVEL OF EVIDENCE: IV, Case Series.

Pediatric pedicle screw placement using intraoperative computed tomography and 3-dimensional image-guided navigation.

STUDY DESIGN: A retrospective cohort study reporting the use of intraoperative computed tomography (CT) and image-guided navigation system for the placement of pedicle screws in pediatric compared with adult patients. OBJECTIVE: To evaluate the accuracy of open pedicle screw placement in pediatric patients using intraoperative CT and 3-dimensional (3D) image-guided navigation. SUMMARY OF BACKGROUND DATA: Pedicle screws are widely used in children for the correction of spinal deformity. Navigation systems and intraoperative CT are now available as an adjunct to fluoroscopy and anatomic techniques for placing pedicle screws and verifying screw position. METHODS: From 2007 to 2010, 984 pedicle screws were placed in a consecutive series cohort of 50 pediatric patients for spinal deformity correction with the use of intraoperative CT (O-arm, Medtronic, Inc, Louisville, CO) and a computerized navigation system (Stealth, Medtronic, Inc, Louisville, CO). The primary outcome measure for this study is redirection or removal of screw on the basis of the intraoperative CT imaging. During the study period, 1511 screws were placed in adult patients using the same image guidance system. RESULTS: A total of 984 pedicle screws were implanted using real-time navigation, with a mean of 20 screws per patient (range: 2-34). On the basis of intraoperative CT, 35 screws (3.6%) were revised (27 redirected and 8 removed), representing a 96.4% accuracy rate. No patients returned to the operating room because of screw malposition.Of the 1511 screws placed in adult patients, 28 (1.8%) were revised intraoperatively for malposition on CT imaging, for an overall 98.2% accuracy rate. Screw revision thus was more common in the pediatric population (P = 0.008). However, the pediatric screw accuracy rate is significantly higher than the findings from a recent meta-analysis of predominantly nonnavigated screws in children, reporting a 94.9% accuracy rate (P = 0.03). CONCLUSION: We report 96.4% accuracy in pediatric pedicle screw placement using intraoperative CT and a 3D navigation system. This is similar to other reports and has better accuracy than a recent meta-analysis of nonnavigated screws in children.