Mini-open pedicle subtraction osteotomy as a treatment for severe adult spinal deformities: case series with initial clinical and radiographic outcomes

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>Pedicle subtraction osteotomy (PSO) is a powerful but high-risk surgical technique for destabilizing the spine for deformity correction in both the sagittal and coronal planes. Numerous reports have demonstrated the benefits of this technique for realigning the spine in a physiological posture; however, the open surgical technique is associated with a high complication rate. In this report the authors review data obtained in a series of patients who underwent PSO through a less invasive approach.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>Sixteen patients with severe coronal- and/or sagittal-plane deformities were treated in this series. Conservative measures had failed in all cases and patients had undergone a single-level PSO or extended PSO at L-2 or L-3. Fixation was accomplished using percutaneous instrumentation and interbody or facet joint fusions were used at the remaining levels. None of the procedures were aborted or converted to a traditional open procedure. Standard clinical and radiographic measures were used to assess patient outcomes.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Mean age was 68.8 years and mean follow-up duration was 17.7 months. An average of 7.6 levels were fused, and 50% of the patients had bilateral iliac screw fixation, with all constructs crossing both the thoracolumbar and lumbosacral junctions. Operative time averaged 356 ± 50 minutes and there was a mean blood loss of 843 ± 339 ml.</jats:p> <jats:p>The leg visual analog scale score improved from a mean of 5.7 ± 2.7 to one of 1.3 ± 1.6, and the back visual analog scale score improved from a mean of 8.6 ± 1.3 to one of 2.4 ± 2.1. The Oswestry Disability Index score improved from a mean of 50.1 ± 14.4 to 16.4 ± 12.7, representing a mean reduction of 36.0 ± 16.9 points. The SF-36 physical component summary score changed from a mean of 43.4 ± 2.6 to one of 47.0 ± 4.3, and the SF-36 mental component summary score changed from a mean of 46.7 ± 3.6 to 46.30 ± 3.0.</jats:p> <jats:p>Coronal alignment improved from a mean of 27.9 ± 43.6 mm to 16.0 ± 17.2 mm. The lumbar Cobb angle improved from a mean of 41.2° ± 18.4° to 15.4° ± 9.6°, and lumbar lordosis improved from 23.1° ± 15.9° to 48.6° ± 11.7°. Pelvic tilt improved from a mean of 33.7° ± 8.6° to 24.4° ± 6.5°, and the sagittal vertical axis improved from 102.4 ± 73.4 mm to 42.2 ± 39.9 mm. The final lumbar lordosis–pelvic incidence difference averaged 8.4° ± 12.1°. There were 4 patients who failed to achieve less than or equal to a 10° mismatch on this parameter. Ten of the 16 patients underwent delayed postoperative CT, and 8 of these had developed a solid arthrodesis at all levels treated. A total of 6 complications occurred in this series. There were no cases of symptomatic proximal junction kyphosis.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Advancements in minimally invasive technique have resulted in the ability to manage increasingly complex deformities with hybrid approaches. In this limited series, the authors describe the results of utilizing a tissue-sparing mini-open PSO to correct severe spinal deformities. This method was technically feasible in all cases with acceptable radiographic outcomes similar to open surgery. However, high complication rates associated with these deformity corrections remain problematic.</jats:p></jats:sec>

Minimally invasive instrumentation without fusion during posterior thoracic corpectomies: a comparison of percutaneously instrumented nonfused segments with open instrumented fused segments

“…After cannulation of the pedicles, facets can be decorticated and graft can be inserted into the facet joint to promote fusion. 26 This type of facet joint fusion has been shown to provide similar fusion rates to open posterior lateral fusion for lumbar spondylolistheisis. 18 In addition, this focused facet fusion technique has been used during mini-open pedicle subtraction osteotomy with long-segment thoracolumbar percutaneous instrumentation for deformity correction and has demonstrated at least an 80% solid fusion rate on follow-up CT imaging.…”

“…18 In addition, this focused facet fusion technique has been used during mini-open pedicle subtraction osteotomy with long-segment thoracolumbar percutaneous instrumentation for deformity correction and has demonstrated at least an 80% solid fusion rate on follow-up CT imaging. 26 This study is subjected to limitations inherent to its retrospective design and the novelty of the surgical technique. Specifically, the patient cohort is at risk for selection biases and confounders.…”

“…Percutaneous fixation above and below the pathology can be performed for spinal stabilization. 2,3,13,19,20,26 Another major technical challenge to MIS techniques is the limited ability to perform extensive and robust arthrodesis to promote bony fusion during percutaneous instrumentation. 6,23 Therefore, there is appropriate clinical concern and uncertainty as to the longevity of performing complex spinal reconstruction (3-column surgery) with percutaneous instrumentation without fusion.…”

The double-transforaminal lumbar interbody fusion: an innovative one-stage surgical technique for posterior kyphosis correction

“…Further safety might be achieved by spinal monitoring which was not used in our case. In addition, percutaneous instrumentation as recommended by other authors 24 for PSO at levels below L2 seem to be obsolete in the Double TLIF Osteotomy. We do not see a disadvantage in the open technique not least because other investigators found similar clinical and radiological outomes between MIS TLIF and conventional TLIF.…”

Role of minimally invasive surgery for adult spinal deformity in preventing complications

“…These procedures have been associated with a higher risk of complications [35]. Although a mini-open PSO is feasible, the technique remains challenging [36]. Anterior column reconstruction involving the combination of lateral lumbar discectomy, ALL release, and placement of hyperlordotic grafts through a miniopen lateral retroperitoneal approach has recently been implemented to avoid PSO or VCR.…”