Preventing proximal junctional failure in long segmental instrumented cases of adult degenerative scoliosis using a multilevel stabilization screw technique.

BACKGROUND: The authors sought to demonstrate the safety and effectiveness of the multilevel stabilization screw (MLSS) technique in decreasing the incidence of proximal junctional failure in long segmental instrumented fusions for adult degenerative scoliosis. METHODS: Institutional review board approval was obtained and all patients with adult spinal deformity who underwent the MLSS technique were analyzed. A neuro-radiologist and spine-focused neurosurgeon not involved with the surgical treatment performed radiographic analysis. Proximal junctional angle was defined as the caudal endplate of the upper instrumented vertebra (UIV) to the cephalad endplate of two supradjacent vertebrae above the UIV. The UIV is defined as the most cephalad vertebra completed captured by the instrumentation. Abnormal proximal junctional kyphosis (PJK) was defined as proximal junctional sagittal Cobb angle >10 degrees and proximal junction sagittal Cobb angle at least 10 degrees greater than the preoperative measurement. The presence of both is criteria necessary to be considered abnormal. RESULTS: Twenty patients with degenerative scoliosis underwent the MLSS technique with the upper-instrumented vertebrae in the proximal thoracic spine. Fifteen patients met inclusion criteria with greater than 12 months radiographic and clinical follow up. Three patients were excluded due to lack of follow up imaging and two patients were excluded due to the inability to measure the UIV. Age range was 44-84 years with a mean of 66. Eleven of the 15 patients were over the age of 60 at the time of surgery. The male-to-female ratio was 4:11. Body mass index (BMI) range was 24-44 with a mean of 31.5 units. The follow up period ranged from 14 to 58 months with an average follow up of 30 months. The mean change in Cobb angle at the proximal junction was 4.00 degrees with a range from -0.92 to 9.13 degrees. There were no fractures or instrumentation failures at or near the proximal junction. There was no revision surgeries performed for proximal junctional failure. Retrospective clinical questionnaires revealed that surgical expectations were met in 15 of 19 patients surveyed, 79%. One patient was not reachable for a postoperative phone interview. In patients who were not satisfied with their overall experience, the change in Cobb angle ranged from -0.92 to 9.13 degrees with an average change of 3.90 degrees. Whereas patients reporting an overall positive experience had a change in Cobb angle range from -0.12 to 8.07 degrees with an average change of 4.05 degrees. CONCLUSION: PJK and failure are well-recognized suboptimal outcomes of long-segmental fusions of the thoracolumbar spine that can lead to significant neurological morbidity and costly revision surgeries. With no known proximal junction failures to date, the MLSS technique has shown promising results in preventing adverse proximal junctional conditions and can be safely performed under fluoroscopy guidance. Future direction includes a comparative study establishing the relative risk of developing PJK with this novel technique versus a traditional long-segmental thoracolumbar fusion.

Definitive single-stage posterior surgical correction of complete traumatic spondyloptosis at the thoracolumbar junction.

Complete dislocation at the thoracolumbar junction is a rare occurrence, with only 4 previously reported cases in 3 separate series. Surgical procedures in the reported cases of spondyloptosis at the thoracolumbar junction have been described using instrumentation, reduction, decompression, and stabilization techniques. In this report the authors' patient presented with spondyloptosis at the thoracolumbar junction, resulting in a T-11 American Spinal Injury Association Grade A injury. The authors corrected the patient's thoracolumbar spondyloptosis with surgical reconstruction without the use of leveraged instrumented reduction. They describe a single-stage, posterior-only spinal realignment, reconstruction, and stabilization. Within months of beginning postoperative therapy, the patient enrolled and attended courses at a local college and regained personal independence by learning to drive a motor vehicle with a hand control. Two-year radiographic and clinical follow-up confirms solid fusion across the reconstruction.

A chitosan-hyaluronan-based hydrogel-hydrocolloid supports in vitro culture and differentiation of human mesenchymal stem/stromal cells.

Three-dimensional (3D) cell culture platforms are increasingly utilized due to their ability to more closely mimic the in vivo microenvironment compared to traditional two-dimensional methods. Limitations of currently available 3D materials include lack of cell attachment, long polymerization times, and inclusion of undefined xenobiotics, and cytotoxic cross-linkers. Evaluated here is a unique hydrogel comprised of polyelectrolytic complex (PEC) fibers formed by hyaluronic acid and chitosan (CT). When hydrated with fetal bovine serum containing human mesenchymal stem/stromal cells (hMSCs), a hydrogel with an elastic modulus of 264±38 Pa formed in seconds with cells distributed throughout the matrix. Scanning electron microscopy showed a lattice-like meshwork of PEC fibers forming irregular compartments. hMSCs showed 48% viability during the first 24 h, with cell populations thereafter reaching a steady state for 14 days. hMSCs in the matrix were induced to differentiate to chondrogenic, osteogenic, and adipogenic phenotypes. Emergent features, at days 56 and 70, consisted of chondrogenesis on the surface of hydrogels induced to osteogenic and adipogenic phenotypes. Results indicate that this matrix may be useful for tissue engineering and disease modeling applications.

Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique.

BACKGROUND: The underlying pathophysiology leading to syringomyelia is elusive with multiple flow-related theories constituting our current limited understanding of the disease process. Syringomyelia is associated with pathologies related to the disturbance of cerebral spinal fluid flow found in conditions such as Chiari I malformations, spinal malignancy, spinal cord tethering, trauma, or arachnoid adhesions. Our aim is to describe a unique surgical shunting technique used to treat refractory cases of idiopathic syringomyelia. METHODS: Five patients, aged 22-50, presented with progressive neurologic symptoms associated with an idiopathic syrinx. All underwent decompressive laminectomy surgery with syringosubarachnoid shunting using the silastic wedge technique. RESULTS: In five cases of idiopathic syringomyelia, clinical and radiographic follow up ranges from 3 to 36 months. Three patients have radiographic and clinical follow up greater than 24 months. All patients improved clinically and their symptoms have been stable. CONCLUSIONS: Shunting procedures for the syringomyelia disease spectrum have been criticized due to the inconsistent long-term outcomes. This surgical technique used to treat symptomatic idiopathic syringomyelia has been devised based on our intraoperative experience, surgical outcomes, and evaluation of the literature. The purpose of the wedges is to preserve patency of the communication between the syrinx cavity and the expanded subarachnoid space by preventing healing of the myelotomy edges and by maintaining an artificial conduit between the syrinx cavity and the subarachnoid space. Although short-term results are promising, continued long-term follow up is needed to determine the ultimate success of the silastic wedge shunting procedure.

Antibiotic-impregnated polymethylmethacrylate as an anterior biomechanical device for the treatment of cervical discitis and vertebral osteomyelitis: technical report of two cases.

AIM: To evaluate the feasibility of this novel surgical approach for treatment of cervical discitis and vertebral osteomyelitis. MATERIAL AND METHODS: This is a report of two patients who underwent anterior cervical decompression for discitis and vertebral osteomyelitis (DVO) with cervical spine reconstruction with polymethylmethacrylate impregnated with antibiotics (AI-PMMA). RESULTS: Both patients had successful procedures that were followed by 6 weeks of intravenous antibiotics. Stabilization and eradication of infection was achieved with clinical and radiographic stabilization seen in both. Follow-up is greater than 18 months and both patients remain off antibiotics. CONCLUSION: The described technique using AI-PMMA offers immediate structural stability and local delivery of high concentration of antibiotics. Use in two patients has demonstrated a cost effective, long-term biomechanically stable construct and infection control.

Multipotent adult progenitor cells from swine bone marrow.

We show that multipotent adult progenitor cells (MAPCs) can be derived from both postnatal and fetal swine bone marrow (BM). Although swine MAPC (swMAPC) cultures are initially mixed, cultures are phenotypically homogenous by 50 population doublings (PDs) and can be maintained as such for more than 100 PDs. swMAPCs are negative for CD44, CD45, and major histocompatibility complex (MHC) classes I and II; express octamer binding transcription factor 3a (Oct3a) mRNA and protein at levels close to those seen in human ESCs (hESCs); and have telomerase activity preventing telomere shortening even after 100 PDs. Using quantitative-reverse transcription-polymerase chain reaction (Q-RT-PCR), immunofluorescence, and functional assays, we demonstrate that swMAPCs differentiate into chondrocytes, adipocytes, osteoblasts, smooth muscle cells, endothelium, hepatocyte-like cells, and neuron-like cells. Consistent with what we have shown for human and rodent MAPCs, Q-RT-PCR demonstrated a significant upregulation of transcription factors and other lineage-specific transcripts in a time-dependent fashion similar to development. When swMAPCs were passaged for 3-6 passages at high density (2,000-8,000 cells per cm(2)), Oct3a mRNA levels were no longer detectable, cells acquired the phenotype of mesenchymal stem cells (CD44(+), MHC class I(+)), and could differentiate into typical mesenchymal lineages (adipocytes, osteoblasts, and chondroblasts), but not endothelium, hepatocyte-like cells, or neuron-like cells. Even if cultures were subsequently replated at low density (approximately 100-500 cells per cm(2)) for >20 PDs, Oct3a was not re-expressed, nor were cells capable of differentiating to cells other than mesenchymal-type cells. This suggests that the phenotype and functional characteristics of swMAPCs may not be an in vitro culture phenomenon.