Is Open Surgery for Metastatic Spinal Cord Compression Secondary to Lung Cancer Really Beneficial? A Systematic Review

Biomechanical evaluation of pedicle screw stability after 360-degree turnback from full insertion: effects of screw shape, pilot hole profile and bone density

Intraoperative pedicle screw depth adjustment after initial insertion, including both forward and backward adjustments, is sometimes necessary to facilitate rod application and ensure that the screw is in the correct position, which is determined by intraoperative fluoroscopy. Adjusting the screw with forward turns has no negative influence on the screw fixation stability; however, screw turnback may weaken the fixation stability. The aim of this study is to evaluate the biomechanical properties of screw turnback and demonstrate the reduction in the fixation stability after the screw is turned 360° from its full insertion position. Commercially available synthetic closed-cell polyurethane foams with three different densities simulating various degrees of bone density were utilized as substitutes for human bone. Two different screw shapes (cylindrical and conical) together with two different pilot hole profiles (cylindrical and conical) were tested. Following specimen preparation, screw pullout tests were conducted using a material test machine. The mean maximal pullout strength between full insertion and 360-degree turnback from full insertion in each setting was statistically analyzed. The mean maximal pullout strength after 360-degree turnback from full insertion was generally lower than that at full insertion. The reduced mean maximal pullout strength after turnback increased with decreasing bone density. Conical screws had significantly lower pullout strength after 360-degree turnback than cylindrical screws. The mean maximal pullout strength was reduced by up to approximately 27% after 360-degree turnback when using a conical screw in a low bone density specimen. Additionally, specimens treated with a conical pilot hole presented a less reduction in pullout strength after screw turnback as compared to those with a cylindrical pilot hole. The strength of our study was that we systematically investigated the effects of various bone densities and screw shapes on screw stability after turnback, which has rarely been reported in the literature. Our study suggests that pedicle screw turnback after full insertion should be reduced in spinal surgeries, particularly procedures that use conical screws in osteoporotic bone. Pedicle screw secured with a conical pilot hole might be beneficial for screw adjustment.

Prognostic factors and outcomes of surgical intervention for patients with spinal metastases secondary to lung cancer: an update systematic review and meta analysis

PURPOSE

Lung cancer is one of the most common malignant tumors. Most patients develop spinal metastases during the course of cancer and suffer skeletal-related events. Currently, no consensus has been reached on the prognostic factors in patients undergoing surgeries. This study aimed to answer two questions: (1) what are the effects of surgical intervention, and (2) what are the factors associated with postoperative survival.

METHODS

Searches were performed on electronic databases including PubMed, Ovid/MEDLINE, Cochrane, and Scopus for articles published before February of 2022, involving the survival factors of patients with spinal metastasis. Multiple data items were considered, such as baseline demographics, surgical details, clinical outcome, and prognostic factors. The analysis was performed in Review Manager (RevMan) 5.5. The prognostic factors of survival were analyzed with univariate and multivariate cox regression analysis.

RESULTS

Finally, 14 studies with 813 patients were identified. Their 6, 12, and 24 months survival rates ranged from 18 to 58%, 18 to 22.4%, and 0 to 58.5%, respectively. The pooled hazard ratio of preoperative ambulatory status and the number of involved vertebrae demonstrated statistical significance, while no significant prognostic effect on the overall survival was found for targeted therapy, visceral metastases, chemotherapy, radiotherapy, or postoperative ambulatory status.

CONCLUSION

Overall, surgical intervention could achieve significant pain relief and neurological function improvements. For patients receiving surgery for spinal metastasis from lung cancer, preoperative ambulatory status and the number of involved vertebrae were significant prognostic factors associated with their survival.

Management of Lung Cancer Presenting with Solitary Bone Metastasis

Lung neoplasm is the main cause of cancer-related mortality, and bone metastasis is among the most common secondary tumors. The vast majority of patients also present with multiple bone metastases, which makes systemic and adjuvant pain therapy preferable to surgery. The optimal approach for a resectable non-small-cell lung tumor that also presents a unique, resectable bone metastasis is not fully established. The number of papers addressing this subject is small, and most are case reports; nevertheless, survival rates seem to increase with radical surgery. The sequencing of local versus systemic treatment should always be discussed within the multidisciplinary team that will choose the best approach for each patient. As targeted systemic therapies become more accessible, radical surgery, together with existing reconstructive methods, will lead to an increase in life expectancy and a better quality of life.

Effects of Osimertinib Combined With Pulmonary Rehabilitation and Health Care Training on Pulmonary Function, Complications, and Quality of Life in Patients After Radical Resection of Lung Cancer

Objective

To explore the effects of osimertinib combined with pulmonary rehabilitation and health care training on pulmonary function, complications, and the quality of life (QOL) in patients after radical resection of lung cancer.

Methods

The data of 120 patients with radical resection of lung cancer admitted to The First Affiliated Hospital of Zhengzhou University from February 2020 to February 2021 were retrospectively analyzed. According to the order of admission, they were equally divided into group p and group q. All patients were given pulmonary rehabilitation and health care training, and group p was treated with osimertinib, while group q received the treatment of pemetrexed combined with cisplatin. The pulmonary function, the incidence of complications, and QOL between the two groups were compared.

Results

Compared with group q, the pulmonary function was higher (P < 0.001), the incidence of complications was significantly lower (P < 0.05), and QOL scores were markedly higher in group p after treatment (P < 0.001).

Conclusion

The combination of osimertinib and pulmonary rehabilitation and health care training can improve the pulmonary function of patients with non-small cell lung cancer (NSCLC) with radical resection of lung cancer, and reduce their postoperative morbidity, thereby improving their QOL, which is conducive to reducing the patient's and society's medical burden.

Novel Dual-Threaded Pedicle Screws Provide Fixation Stability That Is Comparable to That of Traditional Screws with Relative Bone Preservation: An In Vitro Biomechanical Study

Replacement with larger diameter screws is always used in pedicle screw loosening but carries a risk of pedicle wall violation. A pedicle screw with more preserved bone stock is the preferred primary fixation choice. The purpose of this study was to evaluate whether a newly designed proximal-conical dual-thread screw with less bone occupancy provides fixation strength comparable to that of a traditional screw. Six types of pedicle screws based on three different shapes (cylindrical, conical, and proximal-conical) and two thread profiles (single-thread and dual-thread) were grouped. Conical and proximal-conical screws differed mainly in the slope of the outer diameter from the hub to the tip. Conical screws had an outer diameter (6.5 mm) that differed from the hub and tapered by 30% to an outer diameter (4.5 mm) at the tip and proximal-conical screws had the same outer diameter from the hub and tapered by 30% (4.5 mm) at 20 mm from the hub and then maintained the outer diameter (45 mm) to the tip. A total of 36 L4 Sawbones® vertebrae were used in the study and six trials for each screw group. The results of the imaging, screw volume in bone, insertion torque, and pullout force were analyzed. For screws with the same shape, insertion torque and pullout force were significantly higher for those in the dual-thread groups than for those in the single-thread groups (p < 0.05). For screws with the same thread profile, there was no significant difference in either biomechanical test between the different screw shapes (p > 0.05). Our results demonstrated that these proximal-conical dual-thread screws, with the property of relative bone stock preservation, display a comparable biomechanical performance to traditional dual-thread screws and a better performance than single-thread screws. This screw design could serve as the primary pedicle screw choice to reduce revision difficulty.