Relation of lumbar sympathetic chain to the open corridor of retroperitoneal oblique approach to lumbar spine: an MRI study.

BACKGROUND: Retroperitoneal oblique approach to lumbar spine used surgical corridor between psoas muscle and aorta for exposure to anterior part of lumbar spine. Lumbar sympathetic chain (LSC) runs in the corridor to make it a structure at risk of injury. RESEARCH QUESTION: Does LSC relationship with surgical corridor for minimally invasive retroperitoneal anterolateral oblique approach change in different intervertebral disc level? METHODS: Left LSC was identified in axial magnetic resonance imaging images at L2-3, L3-4 and L4-5 intervertebral disc levels of 144 patients. Distances between LSC and left psoas muscle and aorta were recorded. RESULTS: Mean age of the patients was 62.3 years. LSC was identifiable in 90.9% of levels. Distance between LSC and psoas muscle at L2-3, L3-4 and L4-5 was 4.0 mm, 4.7 mm and 5.2 mm. Statistical difference was found between L2-3 and L4-5 level (p = 0.006). Distance between LSC and aorta at each level was 12.4 mm, 12.3 mm and 10.6 mm without statistical difference. In non-scoliosis group distance between LSC and psoas muscle at each level was 3.1 mm, 3.3 mm and 4.0 mm. Statistical difference was found between L2-3 and L4-5 level (p = 0.012) and between L3-4 and L4-5 level (p = 0.041). Distance between LSC and aorta at each level was 11.9 mm, 11.4 mm and 10.2 mm. Statistical difference was found between L2-3 and L4-5 disc level (p = 0.039). CONCLUSION: LSC moves away from psoas muscle and becomes closer to aorta in L4-5 disc level. These slides can be retrieved under Electronic Supplementary Material.

Accuracy of cervical pedicle screw placement using the funnel technique.

STUDY DESIGN: This was a cadaver study assessing the accuracy of cervical pedicle screw placement. OBJECTIVE: To evaluate the accuracy of the funnel technique of screw placement. SUMMARY OF BACKGROUND DATA: Although excellent results have been reported in clinical studies, with no major neurovascular injuries, several cadaveric studies have shown a high pedicle perforation rate during screw placement. METHODS: Ten fresh frozen cervical spines (C2-C7) were used (120 pedicles, 20 pedicles per level). The average specimen age was 79.6 years (range 65-97); the average height was 159 cm (range 155-175). The male-to-female ratio was 3:7. Pedicle width and angulation were measured on preoperative axial computed tomography (1-mm slices). By use of four bony landmarks and the funnel technique, screws were placed under direct vision. Critical perforations (documented contact of a screw with, or an injury to, a spinal cord, nerve root, or vertebral artery) and noncritical perforations (a perforation with no critical contact) were recorded. RESULTS: In seven pedicles (5.8%) the procedure was aborted because of a small or nonexistent pedicle medullary canal. Ninety-four pedicle screws (83.2%) were placed correctly, whereas 11 pedicles (9.7%) had noncritical perforations and 8 pedicles (7.1%) had critical perforations. The majority of the critical and noncritical perforations were at C3, C4, and C5. CONCLUSIONS: Axial computed tomography is necessary for the preoperative planning. Because of the small diameter and steep angulation of cervical pedicles, every spine surgeon who intends to use pedicle screws should first master the technique on cadavers.

Scoliosis in arthrogryposis multiplex congenita: results after nonsurgical and surgical treatment.

Forty-six patients (25 male and 21 female) with arthrogryposis multiplex congenita who were seen at the Alfred I. duPont Hospital for Children between the years 1940 and 1997 were evaluated to assess the prevalence and patterns of scoliosis and the long-term results after both nonsurgical and surgical treatment methods. We found the prevalence of scoliosis to be 65.9% (32 of 46 patients). A single thoracolumbar curve was the predominant curve pattern. No congenital curve types or vertebral anomalies were seen in our group of patients. In the nonsurgical group, the mean curve was <30 degrees at follow-up. In the surgical group, the mean primary curve before spinal arthrodesis was 78.5 degrees. Three patients in the surgical group who were nonambulators have become household ambulators at the most recent follow-up. We recommend bracing in patients who are ambulators and have a curve of <30 degrees. Combined anterior and posterior spinal arthrodesis gave the best results.