Nitin Khanna

The reliability and diagnostic value of radiographic criteria in sagittal spine deformities: comparison of the vertebral wedge ratio to the segmental cobb angle.

Study Design. A prospective, radiographic cohort study. Objectives. This study assessed the radiographic reliability and diagnostic value of the vertebral wedge ratio (WR) to the more segmental Cobb angle (CA) regarding sagittal spine deformities. Summary of Background Data. The use of the CA has been used to assist in the radiographic diagnosis of various sagittal spine deformities. However, the reliability and diagnostic aptitude of the CA remains speculative and may not be as receptive to individual variations of vertebral integrity in sagittal spine deformities. Methods. Sixty patients (age range, 8–21 years) who were diagnosed with Scheuermann’s kyphosis (Group 1; n = 16), with postural roundback (Group 2; n = 23), or who were regarded normal (Group 3; n = 21) were radiographically evaluated to assess the reliability and diagnostic potential of the vertebral WR (apex of the curve and 2 adjacent vertebrae) and segmental CA. Radiographic assessment was conducted by 3 independent blinded observers on 3 separate occasions. Results. Very strong intraobserver (WR a = 0.85–0.99; CA a = 0.97–0.99) and interobserver (WR a = 0.79–0.89; CA a = 0.95) reliabilities were noted. A greater degree of WR reliability was noted in Group 1, whereas CA reliability remained consistent in all Groups. A statistically significant difference was found between all Groups in relation to vertebral WR and segmental CA (P < 0.05). Based on relative risk ratio analyses, an apex wedge ratio of ≤0.80 and/or a segmental Cobb angle of ≥20° is highly and significantly associated with Scheuermann’s kyphosis. Conclusion. The segmental CA exhibited a higher degree of reliability than the vertebral WR. The apex vertebral WR exhibited the greatest amount of wedging in the Scheuermann’s patients; whereas in the other groups it remained largely consistent with the adjacent vertebral WRs. An apex vertebral WR ≤0.80 and/or a segmental CA of ≥20° are highly associated with the clinical diagnosis of Scheuermann’s kyphosis. If the segmental CA cannot be ascertained, the apex vertebral WR is a relatively strong reliable alternative, primarily with regards to Scheuermann’s kyphosis. In addition, the type of deformity may potentially dictate the ideal measuring method.

Medialized, Muscle-Splitting Approach for Posterior Lumbar Interbody Fusion: Technique and Multicenter Perioperative Results.

Study Design. Retrospective, multicenter study of perioperative results Objective. The purpose of this study was to describe the surgical technique for medialized posterior lumbar fusion as well as present preliminary complication and treatment results from a multicenter retrospective study. Summary of Background Data. Posterior exposures remain the most commonly performed approaches for spinal fusion. Conventional open posterior exposures, however, have relatively high exposure-related morbidity and postoperative infection rates. Less invasive exposures for transforaminal and anterior (lateral) interbody fusion have been widely used over the past decade, but the need for bilateral posterior exposure has challenged the development of less invasive exposures for direct posterior approaches for lumbar fusion. Methods. Consecutive patients treated with minimally invasive spine (MIS) posterior lumbar interbody fusion with medialized cortical bone trajectory pedicle screw and rod fixation were identified from four sites in the United States. Of the 138 patients identified, 61% of patients were treated for degenerative spondylolisthesis at 167 levels, most commonly at L4–5 (62%). Perioperative treatment, complication, and reoperation data were collected to describe early feasibility of the approach. Results. Mean total operative time was 135 minutes with an average of 236 mL of blood loss. Mean total postoperative length of hospital stay was 2.6 days, with 25% of patients discharged on the same day or within 23 hours of surgery. Total perioperative complication rate in 138 patients was 10.1% (14/138) with three related reoperations. Intraoperative complications included five (3.6%) instances of incidental durotomy, without any progression to persistent cerebrospinal fluid leaks. Nine (6.5%) postoperative complications occurred, including one L5 vertebral body fracture, two pulmonary embolisms, one deep vein thrombosis, one urinary tract infection one instance of urinary retention, two superficial surgical site infections, and one patient with persistent pain at 6 months postoperative. Three (2.2%) reoperations were performed, one for revision of the L5 vertebral body fracture, and two for wound debridement. No instances of postoperative radiculitis or neurological injury were observed. Conclusion. Medialized, muscle-sparing posterior exposures with specialized instrumentation can be performed in patients with degenerative lumbar pathology with low surgical morbidity and blood loss and a short length of postoperative hospital stay. Level of Evidence: 4