Faculty Bibliography

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

BACKGROUND:Multidrug resistant Acinetobacter baumannii (MDR AB) with and without Staphylococcus aureus (SA) is a commonly isolated organism in infected segmental bone defects in combat-related trauma in Iraq and Afghanistan. Although MDR AB in visceral infections is a therapeutic challenge, control of infection appears more common for combat-related osteomyelitis. QUESTIONS/PURPOSES/OBJECTIVE:Using a rat model, we explored the virulence of MDR AB in segmental bone defects alone and in combination with SA. METHODS:Segmental defects in 60 rat femurs were created, stabilized, and inoculated with MDR AB alone and 60 with MDR AB and SA. We performed qualitative and quantitative bacteriology and radiographic assessments at 2, 4, and 8 weeks for MDR AB and at 1, 2, and 3 weeks for MDR AB and SA. RESULTS:Quantitative bacteriology revealed a 3- to 5-log decrease in MDR AB from the initial inoculum. After polymicrobial inoculation, only 10 of 60 animals had positive cultures for MDR AB, whereas 59 of 60 animals had positive cultures for SA. Recovered SA were 2 to 5 log greater than the initial inoculum, while there again was a 3- to 5-log decrease in MDR AB. MDR AB alone did not cause bony lysis, but there was radiographic evidence of new bone formation in 67% of the segmental defects. Osteolysis was noted with MDR AB and SA. CONCLUSIONS:MDR AB did not appear to cause or contribute to clinically apparent osteomyelitis in this pilot study. CLINICAL RELEVANCE/CONCLUSIONS:Resolution of infections in combat-related segmental bone defects inoculated with MDR AB may be attributable to low virulence. Additional studies are needed to confirm low virulence and bone formation with MDR AB.