Flexing a standard hinge-powered operating table for lumbosacral three-column osteotomy (3-CO) site closure in 84 consecutive patients

Three-column osteotomy (3-CO) is a powerful technique in adult deformity surgery, and pedicle subtraction osteotomy (PSO) is the workhorse to correct severe kyphotic spinal deformities. Aging of the population, increasing cases of iatrogenic flat back deformities and understanding the importance of sagittal balance have led to a dramatic increase of this surgical technique. Surgery, however, is demanding and associated with high complication rates so that every step of the procedure requires meticulous technique. Particularly, osteotomy closure is associated with risks like secondary fracture, translation, or iatrogenic stenosis. This step is traditionally performed by compression or a cantilever maneuver with sometimes excessive forces on the screws or instrumentation. Implant loosening or abrupt subluxation resulting in construct failure and/or neurological deficits can result. The aim of this prospective registry study was to assess the efficacy and safety of our surgical PSO technique as well as the osteotomy closure by flexing a hinge-powered OR table. In a series of 84 consecutive lumbosacral 3-CO, a standardized surgical technique with special focus on closure of the osteotomy was prospectively evaluated. The surgical steps with the patients positioned prone on a soft frame are detailed. Osteotomy closure was achieved by remote controlled bending of a standard OR table without compressive or cantilever forces in all 84 cases. This technique carries a number of advantages, particularly the reversibility and the slow speed of closure with minimum force. There was not a single mechanical intraoperative complication such as vertebral body fracture, subluxation, or adjacent implant loosening during osteotomy closure, compared to external cohorts using the cantilever technique (p = 0.130). The feasibility of controlled 3-CO closure by flexing a standard OR table is demonstrated. This technique enables a safe, gentle closure of the osteotomy site with minimal risk of implant failure or accidental neurological injury

Role of Robotics in Improving Surgical Outcome in Spinal Pathologies

The desire to improve accuracy and safety and to favor minimally invasive techniques has given rise to spinal robotic surgery, which has seen a steady increase in utilization in the past 2 decades. However, spinal surgery encompasses a large spectrum of operative techniques, and robotic surgery currently remains confined to assistance with the trajectory of pedicle screw insertion, which has been shown to be accurate and safe based on class II and III evidence. The role of robotics in improving surgical outcomes in spinal pathologies is less clear, however

Regenerative and Immunogenic Characteristics of Cultured Nucleus Pulposus Cells from Human Cervical Intervertebral Discs

<div><p>Cell-based regenerative approaches have been suggested as primary or adjuvant procedures for the treatment of degenerated intervertebral disc (IVD) diseases. Our aim was to evaluate the regenerative and immunogenic properties of mildly and severely degenerated cervical nucleus pulposus (NP) cells with regard to cell isolation, proliferation and differentiation, as well as to cell surface markers and co-cultures with autologous or allogeneic peripheral blood mononuclear cells (PBMC) including changes in their immunogenic properties after 3-dimensional (3D)-culture. Tissue from the NP compartment of 10 patients with mild or severe grades of IVD degeneration was collected. Cells were isolated, expanded with and without basic fibroblast growth factor and cultured in 3D fibrin/poly (lactic-co-glycolic) acid transplants for 21 days. Real-time reverse-transcription polymerase chain reaction (RT-PCR) showed the expression of characteristic NP markers <i>ACAN</i>, <i>COL1A1</i> and <i>COL2A1</i> in 2D- and 3D-culture with degeneration- and culture-dependent differences. In a 5,6-carboxyfluorescein diacetate N-succinimidyl ester-based proliferation assay, NP cells in monolayer, regardless of their grade of degeneration, did not provoke a significant proliferation response in T cells, natural killer (NK) cells or B cells, not only with donor PBMC, but also with allogeneic PBMC. In conjunction with low inflammatory cytokine expression, analyzed by Cytometric Bead Array and fluorescence-activated cell sorting (FACS), a low immunogenicity can be assumed, facilitating possible therapeutic approaches. In 3D-culture, however, we found elevated immune cell proliferation levels, and there was a general trend to higher responses for NP cells from severely degenerated IVD tissue. This emphasizes the importance of considering the specific immunological alterations when including biomaterials in a therapeutic concept. The overall expression of Fas receptor, found on cultured NP cells, could have disadvantageous implications on their potential therapeutic applications because they could be the targets of cytotoxic T-cell activity acting by Fas ligand-induced apoptosis.</p></div

Age, operated cervical segment and corresponding grade of degeneration.

<p>Age, operated cervical segment and corresponding grade of degeneration.</p

Surface marker expression of NP cells.

<p>NP cells were labeled with specific antibodies and analyzed by FACS. The percentage of marker positive cells (mean ± SEM; n = 5) is shown as a comparison between NP cells from patients with mild (white bars) or severe (black bars) degeneration; * p≤0.05.</p

Cell survival and matrix formation of NP transplants.

<p>Cell survival of NP cells in transplants cultivated for 21 days was demonstrated for all samples by PI/FDA staining, with living cells appearing green and dead cells in red (<b>A</b>). Scaffold fibers appeared slightly red as indicated (see arrow). Proteoglycan production in these transplants was verified by Safranin O staining (<b>B</b>) for all samples except for grafts from donor 4. The collagen type II analysis (<b>C</b>) revealed only slight staining for transplants of cells from donors 1, 3 and 4 cultivated with basicFGF and for donor 4 without basicFGF; (<b>A</b> 100x, scale bar: 200 μm; <b>B</b> and <b>C</b> 400x, scale bars: 50 μm). Pictures are representative of n = 5 donors.</p

Cytokine secretion in co-cultures of NP cells and NP cell-seeded matrices with immune cells.

<p>Supernatants of 5 day co-cultures of PBMC from the same donor as the NP cells <b>(donor)</b> or from an unrelated healthy volunteer <b>(allo)</b> with NP cells (<b>donor+NP; allo+NP</b>) or with NP cell-seeded matrices (<b>donor+matrix; allo+matrix</b>) were evaluated for their secretion of IL-2 <b>(A)</b> and IL-6 <b>(B)</b> by CBA technology. Data are shown as mean ± SEM for n = 5 donors. * p≤0.05 between culture groups. Where no bars are visible, cytokine levels were below the detection limit.</p

MRT scoring of IVD degeneration and NP cell cultivation.

<p>Examples of MRT-scoring for different IVD degeneration grades are given for mild disc degeneration (<b>A</b>) and severe disc degeneration (<b>B</b>). Cells from all samples were able to proliferate with or without basicFGF, and showed a fibroblast-like morphology (<b>C</b>) in primary cell culture. The cells developed a slightly larger, more stretched phenotype (<b>D</b>) during cultivation (passage 2); (<b>C</b> and <b>D</b> 100x, scale bars: 200μm).</p

Overall scoring of the Safranin O staining and the immunochemical collagen type II staining.

<p>stained = +, weakly stained = (+), unstained = -</p><p>Overall scoring of the Safranin O staining and the immunochemical collagen type II staining.</p

Induction of immune cell proliferation by NP cell seeded matrices.

<p>NP cell-seeded matrices were co-cultured with CFSE-labeled donor-type <b>(donor)</b> or allogeneic <b>(allo)</b> PBMC and incubated for 5 days. Immune cell subpopulations were identified by gating on antibody-labeled populations and the extent of proliferation was determined from plots of the CFSE signal for: all viable cells <b>(A)</b>, the T cell subsets CD3+CD8+ <b>(B)</b>, CD3+CD4+ <b>(C)</b>, activated CD25+ cells <b>(D)</b> and CD3-CD56+ NK cells <b>(E)</b>. Results are shown as mean ± SEM for n = 5 donors. A representative photograph of matrix seeded with severely degenerated NP co-cultured with allo PBMC is shown <b>(F)</b>.</p