Osteoblastomas are a rare, benign primary bone tumor accounting for 1% of all primary bone tumors, with 40% occurring within the spine. Gross-total resection (GTR) is curative, although depending on location, this can require destabilization of the spine and necessitate instrumented fixation. Through the use of minimally invasive, muscle-sparing approaches, these lesions can be resected while maintaining structural integrity of the spine. The authors present a case report and technical note of a single patient describing the use of a purely endoscopic technique to resect a right L5 superior articulating process osteoblastoma in a 45-year-old woman. The patient underwent an image-guided endoscopic resection of her superior articulating facet osteoblastoma. Intraoperative CT demonstrated GTR. On postoperative examination, she remained neurologically intact with resolution of her pain. At follow-up, she remained pain free. Resection of lumbar osteoblastoma through a fully endoscopic approach was a safe and effective technique in this patient. This technique allowed for GTR without compromising spinal structural integrity, thus eliminating the need for instrumented fixation.
William C. Newman, Max Vaynrub, Mark H. Bilsky, Ilya Laufer and Ori Barzilai
Max Vaynrub, Brandon P. Hirsch, Jared Tishelman, Dennis Vasquez-Montes, Aaron J. Buckland, Thomas J. Errico and Themistocles S. Protopsaltis
Verifying the adequacy of surgical correction of adult spinal sagittal deformity (SSD) leads to improved postoperative alignment and clinical outcomes. Traditionally, surgeons relied on intraoperative measurements of lumbar lordosis (LL) correction. However, T-1 pelvic angle (TPA) and its component angles more reliably predict postoperative alignment. While TPA is readily measured on standing radiographs, intraoperative radiographs offer poor resolution of the bicoxofemoral axis. A method to recreate this radiographic landmark by extrapolating preoperative measurements has been described. The authors aimed to assess the reliability of measurements of global spinal alignment obtained via geometrical reconstitution of the bicoxofemoral axis on prone intraoperative radiographs.
A retrospective review was performed. Twenty sets of preoperative standing full-length and intraoperative prone 36-inch lateral radiographs were analyzed. Pelvic incidence (PI) and sacral to bicoxofemoral axis distance (SBFD) were recorded on preoperative films. A perpendicular line was drawn on the intraoperative radiograph from the midpoint of the sacral endplate. This was used as one limb of the PI, and the second limb was digitally drawn at an angle that reproduced the preoperatively obtained PI, extending for a distance that matched the preoperative SBFD. This final point marked the obscured bicoxofemoral axis. These landmarks were used to measure the L-1, T-9, T-4, and T-1 pelvic angles (LPA, T9PA, T4PA, and TPA, respectively) and LL. Two spine fellows and 2 attending spine surgeons made independent measurements and repeated the process in 1 month. Mixed-model 2-way intraclass correlation coefficient (ICC) and Cronbach’s α values were calculated to assess interobserver, intraobserver, and scale reliability.
Interobserver reliability was excellent for preoperative PI and intraoperative LPA, T9PA, and T4PA (ICC = 0.88, 0.84, 0.84, and 0.93, respectively), good for intraoperative TPA (ICC = 0.68), and fair for preoperative SBFD (ICC = 0.60) and intraoperative LL (ICC = 0.50). Cronbach’s α was ≥ 0.80 for all measurements. Measuring PI on preoperative standing images had excellent intraobserver reliability for all raters (ICC = 0.89, range 0.80–0.93). All raters but one showed excellent reliability for measuring the SBFD. Reliability for measuring prone LL was good for all raters (ICC = 0.71, range 0.64–0.76). The LPA demonstrated good to excellent reliability for each rater (ICC = 0.76, range 0.65–0.81). The thoracic pelvic angles tended to be more reliable at more distal vertebrae (T9PA ICC = 0.71, range 0.49–0.81; T4PA ICC = 0.62, range 0.43–0.83; TPA ICC = 0.56, range 0.31–0.86).
Intraoperative assessment of global spinal alignment with TPA and component angles is more reliable than intraoperative measurements of LL. Reconstruction of preoperatively measured PI and SBFD on intraoperative radiographs effectively overcomes poor visualization of the bicoxofemoral axis. This method is easily adopted and produces accurate and reliable prone intraoperative measures of global spinal alignment.
M. Burhan Janjua, Jared C. Tishelman, Dennis Vasquez-Montes, Max Vaynrub, Thomas J. Errico, Aaron J. Buckland and Themistocles Protopsaltis
Sitting radiographs are a valuable tool to consider the thoracic compensatory mechanism in patients who are candidates for thoracolumbar correction surgery.