No abstract

Thoracic pedicle screw constructs can be safely used for large-magnitude curves. Curve correction (68%) is powerful for these curves, which are stiff and difficult to manage. Correction should be performed carefully with consideration given to convex compression for cases with concomitant hyperkyphosis for these "at risk" spinal cords. Screw accuracy (96.3%) was excellent in this review. The authors found that screws can consistently be placed according to the preoperative plan even in these large-magnitude curves.

A prospective analysis of consecutive cases of lumbar fusion using the unilateral transforaminal posterior lumbar interbody fusion (TLIF) technique with pedicle screw fixation. The objective of the study was to assess the clinical and radiographic outcome of TLIF and describe the technique and indications in the treatment of degenerative disease of the lumbar spine. Forty patients treated with TLIF for degenerative diseases of the lumbar spine were followed up for a minimum of 2.5 years (mean: 36 months; range: 30-42 months). Twenty-three patients had degenerative disc disease alone, 13 had associated isthmic or degenerative spondylolisthesis, and 4 had recurrent disc herniations at the L4-L5 level. Thirty-six (90%) had solid fusions radiographically at latest follow-up. Seventy-nine percent had excellent or good clinical outcomes. Our patients demonstrated high fusion rates and patient satisfaction.

The posterolateral region of the endplate provides the greatest resistance to subsidence while the central region provides the least resistance. A larger-diameter solid support has the greater MLF and the lower the risk of subsidence, suggesting a more efficient transfer of force to the endplate with the hollow indenters. Parameters such as the geometry of structural support and the position and preparation of the endplate can influence the resistance of an interbody support to subside. Partial removal of the endplate may provide both, for adequate mechanical advantage and a highly vascular site for fusion.

Increasing scores of the WRVAS are strongly correlated with curve magnitude lending construct validity to this type of assessment tool. Patients with "surgery recommended" report more visible deformity on the scale than observed, braced, and postoperative patients, supporting the hypothesis that surgery improves the perceived appearance. Parents perceive more deformity of the ribs and shoulders more than did the patients, but other aspects of the deformity are identified equally. WRVAS scores correlate significantly with curve magnitude and treatment. Parents and patients have similar scores, but with parents perceiving more deformity of the ribs and shoulders than patients.

Most of the radiographic process measures evaluated in this study demonstrated good or excellent reliability. The reliability of measuring the angulation of the disc below the LIV, the apical Nash-Moe rotation, and Risser grading was decreased relative to other measures. The reliability of measuring T2-T5 regional kyphosis was disappointing and poor. With regards to the other 13 measures assessed, our findings support the use of these process measures obtained by experienced deformity surgeons via manual measurement for routine clinical and academic purposes.

Digital measurement showed improved measurement precision and good correlation with manual measurements for the majority of AIS parameters. Absolute differences between manual and digital measurements were generally small. Therefore, digital measures are acceptable as a valid technique for scoliosis evaluation. The importance of digital versus manual measurement reliability will increase as digital radiographic viewing becomes more prevalent.

ASFI is the best method to restore thoracic kyphosis when compared with posterior approaches using only hooks or a hybrid construct in the treatment of thoracic adolescent idiopathic scoliosis.