Anterior Cervical Discectomy and Fusion with Zero-Profile Anchored Spacer Versus Plate and Cage for 3-Level Contiguous Cervical Degenerative Disease: A Systematic Review and Meta-Analysis.

OBJECTIVE: To compare the safety, clinical outcomes, and radiological results of anterior cervical discectomy and fusion (ACDF) with zero-profile anchored spacer (ZPAS) versus plate and cage (PC) for 3-level contiguous cervical degenerative disease. METHODS: The study was registered at PROSPERO (CRD42024512706). The Web of Science core collection, PubMed, and Embase were searched up to February 12, 2024. Review Manager 5.3 was used. The relative risk (RR) and 95% confidence interval were evaluated for dichotomous data. Continuous data were assessed using the mean difference and 95% confidence interval. RESULTS: Nine studies comparing ACDF with ZPAS versus PC for 3-level contiguous cervical degenerative disease were included. The intraoperative blood loss and operation time in ZPAS were significantly less than those in PC. The subsidence rate, loss of cervical alignment, fusion segmental height, and intervertebral disc height were significantly greater in ZPAS than in PC. The cervical alignment and dysphagia rate within 6 months were significantly lower in ZPAS than in PC. The ASD of ZPAS was significantly lower than that of PC according to the sensitivity analysis when 1 study was excluded. No significant differences were identified in the other aspects. CONCLUSIONS: Both ACDF with ZPAS and PC were safe and effective procedures. PC was associated with increased surgical trauma. The ZPAS could better decrease the incidence of ASD and dysphagia. ZPAS was also accompanied by high subsidence rate and poor cervical alignment.

Joint equalization of RSOP and PMD fused probability-aware with square-root cubature Kalman filter for the PDM PCS-64QAM system under extreme scenarios.

Extreme scenario of lightning strikes would generate ultra-fast rotation of state-of-polarization (RSOP) up to 5.1 Mrad/s and large polarization mode dispersion (PMD) in optical ground wire (OPGW). Unfortunately, the conventional multiple modulus algorithm (MMA) cannot equalize these polarization impairments in polarization division multiplexing (PDM) probabilistic constellation shaping (PCS)-64QAM system. Moreover, due to unavoidable linearization errors and higher modulation order, the extended Kalman filter based on measurement equations of concatenated multiplication (EKF-CM) is highly unstable and fails under such scenarios. To address the above issues, we have proposed a joint equalization scheme of PMD and RSOP, which fuses probability-aware with square-root cubature Kalman filter (PA-SCKF). Firstly, according to the characteristic that the amplitude of PCS signals obeys mixed Rician distribution, the scheme combines maximum a posteriori criterion to obtain the optimal radius of constellation ring which the received symbol belongs to, for the sake of calculating the innovations of SCKF. Secondly, it performs joint equalization of PMD and RSOP impairments based on SCKF and time-frequency conversion architecture. 28GBaud PDM PCS-64QAM simulation results demonstrate that our scheme can jointly equalize maximum impairments of 8.34 Mrad/s RSOP and 90ps DGD under entropy of 4.5bits/symbol. Additionally, only 0.9 dB OSNR penalty is obtained after joint equalization of 6 Mrad/s RSOP with 70ps DGD impairments. Even under entropy of 5.5bit/symbol, it can still jointly equalize impairments of 6.05 Mrad/s RSOP with 60ps DGD. Furthermore, 16GBaud PCS-64QAM experimental results indicate that the maximum joint equalization performances of PA-SCKF scheme under entropy of 4.5bit/symbol and 5bit/symbol are 17 Mrad/s RSOP with 52ps DGD, and 9 Mrad/s RSOP with 52ps DGD, respectively. These results manifest that our PA-SCKF scheme outperforms both MMA and EKF-CM schemes. Importantly, its complexity is on an order of O(Llog2 L), which is comparable to that of EKF-CM scheme.