Do you need bone graft extenders for a 2- to 3-level posterior lumbar decompression and fusion with adequate local bone?

The standard of care for degenerative pathology of the lumbar spine has undergone a steady evolution over the past 100 years. In the early 20th century, Albee and Hibbs developed noninstrumented posterior spinal fusion techniques to treat patients with tuberculosis of the spine.1 To combat high rates of pseudoarthrosis, Hibbs used iliac crest bone graft to improve fusion rates. Over the past several decades, segmental instrumentation of the spine has been introduced with polyaxial pedicle screw fixation representing the standard of care today. In addition, there has been extensive research focusing on the development of bone graft extenders (BGE), materials which are used to augment the graft volume for spinal fusion procedures. There are several types of BGE that are currently being used for fusion applications including autogenous bone marrow aspirate, demineralized bone matrix, synthetic bone void fillers (eg, hydroxyapatite, calcium sulfate, b-tricalcium phosphate), and recombinant growth factors. Although BGE may be valuable for promoting fusion in patients without adequate local bone, these materials are not typically required for a 2to 3-level posterior decompression and fusion procedure because spinal instrumentation in conjunction with local autograft are both powerful tools that are generally sufficient for achieving a solid arthrodesis. One of the most important factors for obtaining a successful lumbar fusion is proper surgical technique, regardless of the graft material which is employed. In order to prepare a viable fusion bed, the surgeon should be delicate in his handling of the soft tissues during dissection and preserve the local blood supply which provides oxygen, inflammatory cells, as well as hormonal and endocrine mediators that allow for bony healing. Similarly, the technique for harvesting local bone is another important consideration—this should involve a subperiosteal dissection and the full extent of the spinous processes should be harvested as graft so that it may be placed over bony surfaces that are meticulously decorticated to stimulate fusion. Strict adherence to these surgical principles allows the surgeon to preserve the integrity of the soft-tissue envelope and prepare a large fusion bed supplemented with an adequate amount of graft material. To this end, several studies have demonstrated the efficacy of local bone graft for fusion as a treatment of degenerative lumbar pathology. Kho and Chen evaluated the clinical and radiographic outcomes of 136 patients with spondylolisthesis who underwent 2-level posteolateral lumbar fusions with use of local bone and they reported a 94.85% fusion rate 24 months after surgery. Similarly, Lee et al4 assessed 182 patients with degenerative spondylolisthesis who underwent decompression and 2-level instrumented posterolateral fusion with only local bone. After at least 18 months of followup, the authors identified a bilateral fusion mass in 62% of patients, a unilateral fusion in 31% of patients, and no evidence of fusion in only 7% of patients.4 Clinically, 76% of the patients were determined to have experienced an excellent/good outcome and 19% had a fair outcome. On the basis of their findings, the authors concluded that autogenous local bone may yield both acceptable fusion rates and favorable clinical outcomes. In addition to these retrospective investigations, several prospective analyses of lumbar fusion with local bone have also been published.5–7 Inage et al6 prospectively followed 122 patients undergoing 1to 3-level posterolateral fusion with the use of local bone alone for degenerative spondylolisthesis. After being segregated according to the number of operative levels, the subjects were assessed radiographically and clinically up to 24 months after surgery. In this series, the fusion rates were reported to be 88%, 85%, and 67% for 1-, 2-, and 3-level Received for publication March 18, 2015; accepted April 13, 2015. From the *Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT; and wIndiana Spine Group, Carmel, IN. The authors declare no conflict of interest. Reprints: Peter G. Whang, MD, FACS, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, P.O. Box 28071, New Haven, CT 06520-8071 (e-mail: peter.whang@yale.edu). Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved. CONTROVERSIES IN SPINE SURGERY