Is the lateral transpsoas approach feasible for the treatment of adult degenerative scoliosis?

Abstract

Background: Lumbar degenerative scoliosis is a common condition in the elderly. Open traditional surgical approaches are associated with high-morbidity complication rates. Less invasive options may carry fewer risks in this patient population. A minimally disruptive lateral transpsoas retroperitoneal technique to accomplish interbody fusion was developed to avoid the morbidity of traditional open surgery, but this approach as an anterior stand-alone construction has not been reported yet for the treatment of adult degenerative scoliosis.

Questions/purposes: We determined (1) the clinical outcomes (VAS scores for back and leg, Oswestry Disability Index), (2) the radiographic outcomes (Cobb angle, lumbar lordosis, sacral slope, high-grade subsidence, osseous fusion), and (3) the reoperation and complication rates in an older population undergoing this surgical approach.

Methods: Between 2004 and 2008, 62 patients were treated surgically for adult degenerative scoliosis, of whom 46 (74%) were treated with stand-alone lateral lumbar interbody fusion; 11 of these (24%) were lost to followup before 24 months, leaving the records of 35 patients (nine men, 26 women; mean ± SD age, 68 ± 10 years) available for this retrospective review. General indications for this approach included neurogenic claudication and radicular symptoms with history of chronic low-back pain. A total of 107 levels were treated (mean, three; range, one to seven). Clinical and radiographic outcomes were assessed at a followup of 24 months.

Results: Mean VAS back pain scores improved from 85 mm preoperatively to 27 mm at latest followup (p < 0.001). VAS leg pain scores improved from 91 mm to 24 mm (p < 0.001). Oswestry Disability Index scores improved from 51 to 29 (p < 0.001). Coronal alignment improved from Cobb angles of 21° to 12° (p < 0.001). Lumbar lordosis improved from 33° to 41° (p < 0.001). Sacral slope was enhanced from 28° to 35° (p < 0.001). Fusion rate was 84% at final evaluation. High-grade subsidence was seen in 10 patients (29%). Three patients (9%) needed further surgical intervention.

Conclusions: Use of the lateral approach achieved reasonable coronal and sagittal correction, as well as improvements in pain and function, in mild scoliotic deformities; however, subsidence was a concern, occurring in 29% of patients. Questions still remain regarding the need for additional supplementation or the use of wider cages to prevent subsidence.

Level of evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Fig. 1

A graph shows mean scores for the ODI (bars), VAS back pain (light gray lines and dots), and VAS leg pain (dark gray lines and dots). Postoperative ODI values since the 6-week visit are significantly lower compared to baseline (p < 0.04). All postoperative VAS scores are significantly lower compared to baseline (p < 0.01).

Fig. 2A–B

(A) Preoperative and (B) 24-month AP radiographs demonstrate coronal correction after stand-alone lateral lumbar interbody fusion. Note the rotational and curve correction without the need for pedicle screws.

Fig. 3A–B

(A) Preoperative and (B) 24-month lateral radiographs demonstrate sagittal correction after stand-alone lateral lumbar interbody fusion. Note that, by positioning the cages anteriorly in the disc space, it is possible to increase lordosis, while a posterior positioning of the cage generates a prokyphotic construction.

Fig. 4A–G

(A) Preoperative and (B) 24-month AP radiographs; (C) preoperative and (D) 24-month lateral radiographs; and (E–G) 24-month coronal CT reconstructions demonstrate sagittal and coronal correction and interbody fusion in (E) L1-L2, (F) L2-L3 and L4-L5, and (G) L3-L4. Note also laterolisthesis correction and vertebral derotation.