Pullout force of minimally invasive surgical and open pedicle screws-a biomechanical cadaveric study

Our C-Arm-Free Minimally Invasive Technique for Spinal Surgery: The Thoracolumbar and Lumbar Spine-Based on Our Experiences

Background and Objectives: The implementation of intraoperative imaging in the procedures performed under the guidance of the same finds its history dating back to the early 1990s. This practice was abandoned due to many deficits and practicality. Later, fluoroscopy-dependent techniques were developed and have been used even in the present time, albeit with several disadvantages. With the recent advancement of several complex surgical techniques, which demand higher accuracy and are in conjunction with the existence of radiation exposure hazard, C-arm-free techniques were introduced. In this review study, we aim to demonstrate the various types of these techniques performed in our hospital. Materials and Methods: We have retrospectively analyzed and collected imaging data of C-arm-free, minimally invasive techniques performed in our hospital. The basic steps of the procedures are described, following with a discussion, along with the literature of findings, enlisting the merits and demerits. Results: MIS techniques of the thoracolumbar and lumbar spine that do not require the use of the C-arm can offer excellent results with high precision. However, several disadvantages may prevail in certain circumstances such as the navigation accuracy problem where in the possibility of perioperative complications comes a high morbidity rate. Conclusions: The accustomedness of performing these techniques requires a steep learning curve. The increase in accuracy and the decrease in radiation exposure in complex spinal surgery can overcome the burden hazards and can prove to be cost-effective.

The association between paraspinal muscle parameters and vertebral pedicle microstructure in patients undergoing lumbar fusion surgery

PURPOSE

Lumbar fusion surgery has become a standard procedure in spine surgery and commonly includes the posterior placement of pedicle screws. Bone quality is a crucial factor that affects pedicle screw purchase. However, the relationship between paraspinal muscles and the bone quality of the pedicle is unknown. The aim of the study was to determine the relationship between paraspinal muscles and the ex vivo bony microstructure of the lumbar pedicle.

METHODS

Prospectively, collected data of patients undergoing posterior lumbar fusion for degenerative spinal conditions was analyzed. Pre-operative lumbar magnetic resonance imaging (MRI) scans were evaluated for a quantitative assessment of the cross-sectional area (CSA), functional cross-sectional area (fCSA), and the proportion of intramuscular fat (FI) for the psoas muscle and the posterior paraspinal muscles (PPM) at L4. Intra-operative bone biopsies of the lumbar pedicle were obtained and analyzed with microcomputed tomography (µCT) scans. The following cortical (Cort) and trabecular (Trab) bone parameters were assessed: bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), connectivity density (CD), bone-specific surface (BS/BV), apparent density (AD), and tissue mineral density (TMD).

RESULTS

A total of 26 patients with a mean age of 59.1 years and a mean BMI of 29.8 kg/m2 were analyzed. fCSAPPM showed significant positive correlations with BV/TVTrab (ρ = 0.610; p < 0.001), CDTrab (ρ = 0.679; p < 0.001), Tb.NTrab (ρ = 0.522; p = 0.006), Tb.ThTrab (ρ = 0.415; p = 0.035), and ADTrab (ρ = 0.514; p = 0.007). Cortical bone parameters also demonstrated a significant positive correlation with fCSAPPM (BV/TVCort: ρ = 0.584; p = 0.002; ADCort: ρ = 0.519; p = 0.007). FIPsoas was negatively correlated with TMDCort (ρ =  - 0.622; p < 0.001).

CONCLUSION

This study highlights the close interactions between the bone microstructure of the lumbar pedicle and the paraspinal muscle morphology. These findings give us further insights into the interaction between the lumbar pedicle microstructure and paraspinal muscles.

Is Kummell's Disease a Misdiagnosed and/or an Underreported Complication of Osteoporotic Vertebral Compression Fractures? A Pattern of the Condition and Available Treatment Modalities

This narrative review provides the outcomes of minimally invasive surgery (MIS) and describes the available conservative treatment options for patients with osteoporotic vertebral compression fractures (OVCFs) that have risk factors for Kummell's disease (KD). It aims to explore the evidence, emphasize the possible therapy complications, and aims to propose the most efficient clinical strategies for maintaining a good overall condition of individuals who may suffer from neurological deficits from a late-diagnosed OVCF complication. The secondary objective is to sum up the diagnostic particularities concerning individuals prone to OVCFs and KD, as the major risk factor for developing these severe conditions remains osteoporosis. Findings of our narrative review are based on the results found in PubMed, Embase, and Google Scholar from the beginning of their inception to December 2020, described independently by two authors. All of the studies included in the review focus on reporting the following treatment methods: conservative methods, vertebroplasty, kyphoplasty, targeted percutaneous vertebroplasty, frontal and side-opening cannula vertebroplasty, SpineJack, bone-feeling mesh container treatment, and the difference in the cement viscosity used (high vs. low) and the approach used (unilateral vs. bilateral). The comparison of randomized control trials (RCTs) as well as prospective and retrospective case series showed a comparable efficacy of kyphoplasty and vertebroplasty, and described cement-augmented screw fixation and the SpineJack system as effective and safe. Although it should be noted that several studies revealed inconsistent results in regards to the efficacy of using back braces and analgesics in patients who had vertebral fractures that were overlooked or not enrolled in any active surveillance program to track the patient's deterioration immediately. Nevertheless there are non-standardized guidelines for treating patients with OVCFs and their complications already established. Using these guidelines, a treatment plan can be planned that takes into consideration the patients' comorbidities and susceptibilities. However, the primary approach remains the management of osteoporosis and that is why prophylaxis and prevention play a crucial role. These measures reduce the risk of disease progression. Unfortunately, in the majority of cases these measures are not taken into account and KD develops.