Degenerative lumbar spondylolisthesis: review of current classifications and proposal of a novel classification system.

PURPOSE: To review existing classification systems for degenerative spondylolisthesis (DS), propose a novel classification designed to better address clinically relevant radiographic and clinical features of disease, and determine the inter- and intraobserver reliability of this new system for classifying DS. METHODS: The proposed classification system includes four components: 1) segmental dynamic instability, 2) location of spinal stenosis, 3) sagittal alignment, and 4) primary clinical presentation. To establish the reliability of this system, 12 observers graded 10 premarked test cases twice each. Kappa values were calculated to assess the inter- and intraobserver reliability for each of the four components separately. RESULTS: Interobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation was 0.94, 0.80, 0.87, and 1.00, respectively. Intraobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation were 0.91, 0.88, 0.87, and 0.97, respectively. CONCLUSION: The UCSF DS classification system provides a novel framework for assessing DS based on radiographic and clinical parameters with established implications for surgical treatment. The almost perfect interobserver and intraobserver reliability observed for all components of this system demonstrates that it is simple and easy to use. In clinical practice, this classification may allow subclassification of similar patients into groups that may benefit from distinct treatment strategies, leading to the development of algorithms to help guide selection of an optimal surgical approach. Future work will focus on the clinical validation of this system, with the goal of providing for more evidence-based, standardized approaches to treatment and improved outcomes for patients with DS.

Post-traumatic Vertebral Compression Fracture Treated with Minimally Invasive Biologic Vertebral Augmentation for Reconstruction.

In the United States, there is a high incidence of motor vehicle and sports injuries among the active population causing symptomatic post-traumatic vertebral compression fracture. At our institution, 28 cases of painful post-traumatic vertebral compression fractures (PPT-VCFs) were successfully treated with percutaneous vertebral augmentation (VA) for stabilization and reconstruction with intravertebral polyethylene mesh sac (OptiMesh®, Spineology, Inc., Stillwater, MN) and biological morcelized bone graft. The surgical approach provides an efficacious and controlled minimally invasive delivery mechanism to stabilize and reconstruct VCFs, as well as avoiding serious complications from Polymethylmethacrylate (PMMA) of vertebroplasty and kyphoplasty. The construct for biological bone graft/vertebral augmentation is osteoconductive and osteoinductive, and is used to create biologic vertebral stabilization and reconstruction. The adjacent vertebra integrity is protected by the construct with similar elasticity and physical characteristics of the biologic morcelized bone, more matched to that of adjacent bone than PMMA. The surgical techniques are described herein.

Surgical management of complex post-tuberculous kyphosis among African patients: clinical and radiographic outcomes for a consecutive series treated at a single institution in West Africa.

STUDY DESIGN: Retrospective review of consecutive series. OBJECTIVE: To assess the clinical and radiographic outcomes after surgical management of post-tuberculous kyphosis. Post-tuberculous (TB) kyphosis can lead to progressive pulmonary and neurological deterioration. Surgery is indicated to decompress neural elements and correct the spine deformity. Although posterior vertebral column resection (PVCR) has been established as the treatment of choice for severe TB kyphosis, there is paucity of studies on the clinical outcomes among patients treated in West Africa. METHODS: Clinical and radiographic data of 57 patients (pts) who underwent surgical correction of post-TB kyphosis at a single site in West Africa between 2013 and 2018 (≥ 2-year follow-up in 36 pts, ≥ 1-year FU in 21 pts). Pre- and post-op SRS scores and radiographic outcomes were compared using Paired t test. RESULTS: 57 patients, 36M:21F. Mean age 19 (11-57 years). 22/57 pts (39.3%) underwent pre-op halo gravity traction (HGT) for an average duration of 86 days (8-144 days). HGT pts had a higher baseline regional kyphosis (125.1 ± 20.9) compared to non-HGT pts (64.6 ± 31.8, p < 0.001). Post-HGT regional kyphosis corrected to 101.2 ± 23 (24° correction). 53 pts (92.9%) underwent posterior-only surgery and 4 (7.0%) combined anterior-posterior surgery. 39 (68.4%) had PVCR, 11 (19.3%) PSO, and 16 (28.1%) thoracoplasty. Intraoperative neuromonitoring (IOM) signal changes occurred in 23/57 pts (≈ 40%), dural tear in 5 pts (8.8%), pleural tear in 3 pts (5.3%), ureteric injury in 1 pt (1.7%), and vascular injury in 1 pt (1.7%). Post-op complications included four (7.0%) infection, three (5.3%) implant related, two (3.5%) radiographic (one PJK and one DJK), one (1.7%) neurologic, one (1.7%) wound problem, and two (3.5%) sacral ulcers. IOM changes were similar in the VCR (48.7%) and non-VCR (23.5%) pts, p > 0.05. Complication rates were similar among HGT and non-HGT groups. Significant improvements from baseline were seen in the average SRS Total and domains scores and radiographic measurements for patients who attained 2-year follow-up. CONCLUSION: PVCR ± HGT can provide safe and optimal correction in cases of severe post-TB kyphosis with good clinical and radiographic outcomes in underserved regions.

Innovative grid positioning system (GPS) guidance for minimally invasive spinal surgery.

Symptomatic degenerated spinal discs and spinal stenosis are common problems that can often be treated conservatively, but some require decompressive spinal surgery for relief. Traditional open spinal discectomy is associated with significant tissue trauma, higher morbidity and complication rates, a longer convalescence, and even destabilization of the spine. The trend of spinal surgery is rapidly moving toward less traumatic minimally invasive spine surgery (MISS).1,2 The problem that faces the surgeon performing endoscopic MISS is that it is done with limited surgical exposure and visualization of the surgical field. The surgical field can only be viewed through an endoscope to correlate the lesion/pathology in relationship to imaging studies aided by C-arm fluoroscopy. In response, a logical and simple Grid Positioning System (GPS) was developed to provide a precise surgical trajectory/approach for the disc lesion to undergo decompression. GPS involves 3D geometric triangulation of 3 different planes guided by fluoroscopy for introduction of surgical instruments along a geometric line toward the lesion without compromising healthy anatomical structures. This system facilitates MISS, especially in the morbidly obese. In this chapter, we will describe the GPS system and its application to aid in facilitating minimally invasive decompressive spine surgery for alleviating symptoms of degenerative spinal disease, herniated disc, and spinal stenosis, while avoiding the complications and risks of conventional more traumatic spinal surgery and fusion.

Evolving minimally invasive spine surgery: a surgeon's perspective on technological convergence and digital or control system.

Degenerated spinal disc and spinal stenosis are common problems requiring decompressive spinal surgery. Traditional open spinal discectomy is associated with significant tissue trauma, greater morbidity/complications, scarring, often longer term of convalescence, and even destabilization of the spine. Therefore, the pursuit of less traumatic minimally invasive spine surgery (MISS) began. The trend of spinal surgery is rapidly moving toward MISS. MISS is a technologically dependent surgery, and requires increased utilization of advanced endoscopic surgical instruments, imaging-video technology, and tissue modulation technology for performing spinal surgery in a digital operating room (DOR). It requires seamless connectivity and control to perform the surgical procedures in a precise and orchestrated manner. A new integrated DOR, the technological convergence and control system SurgMatix(R), was created in response to the need and to facilitate MISS with "organized control instead of organized chaos" in the endoscopic OR suite. It facilitates the performance, training, and further development of MISS.

Characterization and surgical outcomes of proximal junctional failure in surgically treated patients with adult spinal deformity.

STUDY DESIGN: Retrospective case series of surgically treated patients with adult spine deformity (ASD). OBJECTIVE: To report the incidence of proximal junctional failure (PJF), characterize PJF and evaluate the outcome of revision surgery for PJF. A modified classification is also proposed. SUMMARY OF BACKGROUND DATA: Although recent reports have shown the catastrophic results of PJF, few reports have shown the incidence, characteristics, and clinical outcomes of PJF in ASD. METHODS: This retrospective analysis reviewed data entered prospectively into a multicenter database. Surgically treated patients with ASD with a minimum 2-year follow-up were included. PJF was defined as any type of symptomatic proximal junctional kyphosis (PJK) requiring surgery. On the basis of our previous classification, the following modified PJK classification was established: grade A, proximal junctional increase of 10° to 19°; grade B, 20° to 29°; and grade C, 30° or more. Three types of PJK were also defined: ligamentous failure (type 1), bone failure (type 2), and implant/bone interface failure (type 3). An additional criterion was added for the presence or absence of spondylolisthesis above the upper instrumentation vertebra (UIV). RESULTS: PJF developed in 23 of the 1668 patients with ASD. The incidence of PJF was 1.4%. The mean age was 62.3 ± 7.9 years, and the mean follow-up was 4.0 ± 2.3 years. Seventeen patients had undergone prior surgical procedures. Six patients had UIV above T8, and 17 had UIV below T9. Six patients had associated spondylolisthesis above the UIV (PJF-S), whereas 17 patients did not (PJF-N). The radiographical data show a significant difference in the preoperative sagittal vertical axis between the PJF-S and PJF-N groups, whereas no significant difference was observed in the preoperative sagittal parameters (5.2 ± 3.9 cm vs. 11.4 ± 6.0 cm, P = 0.04). The most common type of PJF was type 2N. The PJF symptoms consisted of intolerable pain (n = 17), neurological deficits (n = 6), and progressive trunk deformity (n = 1). Eleven patients had additional PJK/PJF and 9 required additional revision surgical procedures. CONCLUSION: The incidence of PJF among surgically treated patients with ASD was 1.4%. The most common type of PJF was 2N. Preoperative large sagittal vertical axis change and large amount of correction was a causative factor for spondylolisthesis above the UIV. After the revision surgery, further PJF was a commonly occurred event.