Study Design.: A retrospective cohort study. Objective.: To evaluate the clinical and radiological efficacies of supplementing minimally invasive lateral lumbar interbody fusion (LLIF) with open posterior spinal fusion (PSF) in adult spinal deformity (ASD). Summary of Background Data.: Minimally invasive techniques have been increasingly applied for surgery of ASD. Few reports have been published that directly compare LLIF combined with PSF to conventional PSF for ASD. Methods.: To evaluate the advantages of minimally invasive LLIF for ASD, patients who underwent minimally invasive LLIF followed by open PSF (combined group) were compared with patients who only underwent PSF (only PSF group). The clinical and radiological outcomes for deformity correction and indirect decompression were assessed. The occurrence of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) were also evaluated. Results.: No significant differences were observed in the clinical outcomes of the Oswestry Disability Index (ODI), visual analog scale, and major complications including reoperations between the groups. No additional advantage was found for coronal deformity correction, but the restoration of lumbar lordosis in the combined group was significantly higher postoperatively (15.3° vs. 8.87°, P = 0.003) and last follow-up (6.69° vs. 1.02°, P = 0.029) compared to that of the only PSF group. In the subgroup analysis for indirect decompression for the combined group, a significant increase of canal area (104 vs. 122 mm²) and foraminal height (16.2 vs. 18.5 mm) was noted. The occurrence of PJK or PJF was significantly higher in the combined group than in the only PSF group (P = 0.039). Conclusion.: LLIF has advantages of indirect decompression and greater improvements of sagittal correction compared to only posterior surgery. LLIF should be conducted considering the above-mentioned benefits and complications including PJK or PJF in ASD. Level of Evidence: 4

Lumbar interbody fusion (LIF) is an excellent treatment option for a number of lumbar diseases. LIF can be performed through posterior, transforaminal, anterior, and lateral or oblique approaches. Each technique has its own pearls and pitfalls. Through LIF, segmental stabilization, neural decompression, and deformity correction can be achieved. Minimally invasive surgery has recently gained popularity and each LIF procedure can be performed using minimally invasive techniques to reduce surgery-related complications and improve early postoperative recovery. Despite advances in surgical technology, surgery-related complications after LIF, such as pseudoarthrosis, have not yet been overcome. Although autogenous iliac crest bone graft is the gold standard for spinal fusion, other bone substitutes are available to enhance fusion rate and reduce complications associated with bone harvest. This article reviews the surgical procedures and characteristics of each LIF and the osteobiologics utilized in LIF based on the available evidence.

Bone fusion is one of the mainstay managements for degenerative spinal diseases and critical-sized bone defects resulting from trauma, tumors, infection, and nonunion. Bone graft materials are required for promoting bone healing, with autografts historically considered the gold standard due to their osteogenic, osteoinductive, and osteoconductive properties. However, donor site morbidities have led to the development of alternative bone graft substitutes. Currently available alternative options for bone fusion include allografts, ceramics, demineralized bone matrix (DBM), and bone morphogenetic proteins (BMPs). Each material has its advantages and disadvantages. Allografts avoid donor site morbidities but lack osteogenic properties and pose disease transmission risks. DBMs are acid-extracted allografts that have osteoconductive and osteoinductive properties but require combination with autografts because of the lack of evidence for their stand-alone use. BMP-2 has potent osteoinductive properties and is considered an ideal fusion material, but faces unresolved challenges related to optimal dosage and carrier. Synthetic peptides, mimicking the cell-binding domain of type I collagen, facilitate the attachment of osteogenic cells (such as osteoblasts) to the graft material and the production of extracellular matrix, leading to improved bone growth at the fusion site. The development of materials with ideal properties is a research hotspot. Recent advancements in biomaterials, such as hydrogels, nanomaterials, and three-dimensional-printed biomaterials, offer promising future options for bone fusion. This review provides an overview of available bone fusion materials, their advantages and disadvantages, and introduces emerging candidate options for bone fusion.

Bahk JH, et al. J Korean Med Sci. 2020 Sep;35(40):e345. https://doi.org/10.3346/jkms.2020.35.e345

Background: Vertebroplasty (VP) is considered an alternative therapy in an osteoporotic compression fracture that failed conservative treatment. However, cement leakage into the intradural space can cause catastrophic complications. To the best of our knowledge, intradural cement leakage following VP has been reported only in 7 cases. We report here a case of intradural cement leakage following VP with a literature review. Case presentation: An 84-year-old female with an L1 osteoporotic fracture underwent percutaneous VP at a local hospital. Immediately after the procedure, she complained of weakness, numbness, and pain in both legs, and her back pain aggravated. She was transferred to our hospital. The initial muscle power was grade 2 for the right leg and grade 4 for the left leg. Computed tomography (CT) scan showed intradural cement leakage from T10 to L2. Magnetic resonance imaging showed an intradural mass lesion. Although we performed total laminectomy with durotomy and removed intradural cement completely, the neurological deficit did not completely recover. The muscle power was grade 3 for the right leg and grade 4 for the left leg at the last follow-up. Conlcusions: If a neurological deficit is found after VP, a CT scan should be taken to confirm the pattern of cement leakage. In case of intradural cement leakage, surgical decompression should be recommended to improve neurological deficit. To prevent intradural cement leakage during the VP, the needle tip should not perforate the medial wall of the pedicle with appropriate viscosity of cement.

Ha KY, et al. Clin Orthop Surg. 2015 Sep;7(3):344-350. http://dx.doi.org/10.4055/cios.2015.7.3.344