Novel Three-Holed Titanium Plate Fixation during Open Door Laminoplasty for Cervical Spondylotic Myelopathy: Comparison with Conventional Titanium Plate.

OBJECTIVE: For reconstructing the posterior cervical muscular-ligament complex, attachment points and various modified techniques were designed and applied in clinical practice. This study investigated the clinical and radiographic outcomes of open door laminoplasty with modified centerpiece mini-plate fixation and extensor attachment point reconstruction in the treatment of cervical spondylotic myelopathy (CSM). METHODS: Sixty-nine patients with CSM who underwent C3-C7 open door laminoplasty at our hospital from January 2016 to May 2018 were divided into two groups: 37 and 32 patients underwent laminoplasty with modified and conventional centerpiece titanium plate fixation (MPF and CPF groups), respectively. Changes in cervical spinal angle (CSA), cervical range of motion (ROM), posterior cervical muscle atrophy, neurological function (Japanese Orthopaedic Association [JOA] score), Neck Disability Index (NDI), and axial symptom severity were compared between the two groups. RESULTS: There were no significant differences in operative duration (136.7 ± 23.9 vs 128.3 ± 21.5 min, t = 1.525, p > 0.05), volume of intraoperative blood loss (275.9 ± 33.1 vs 268.2 ± 31.6 ml, t = 0.984, p > 0.05), lamina open angle (41.2° ± 4.5° vs 39.4° ± 4.1°, t = 1.726, p > 0.05), and spinal cord drift distance (2.4 ± 0.3 vs 2.3 ± 0.4 mm, t = 1.184, p > 0.05) between the two groups. After surgery, JOA score significantly increased (p < 0.05), and neurological recovery rates were similar (62.7% vs 63.4%, t = 0.208, p > 0.05). The NDI score was significantly decreased in both the groups (p < 0.05); however, the MPF group recovered to a greater degree than the CPF group (8.3 ± 1.2 vs 9.8 ± 1.4) (t = 4.793, p < 0.05). There was no significant change in cervical ROM postoperatively compared with preoperatively in either group (p > 0.05). CSA decreased from 21.7° ± 2.8° to 18.3° ± 2.1°, and posterior cervical muscle cross-sectional area decreased from 35.2 ± 4.9 cm2 to 31.0 ± 4.1 cm2 in the CPF group (p < 0.05), but no significant change was observed in the MPF group (20.6° ± 2.5° to 20.4° ± 2.6°and 35.9 ± 5.1 to 34.1 ± 4.6 cm2 , respectively) (p > 0.05). Postoperative axial symptom severity was significantly worse in the CPF group than in the MPF group (Z = -2.357, p < 0.05). CONCLUSIONS: As an improvement to the conventional titanium plate, the modified centerpiece titanium plate effectively provides an attachment point for the posterior muscle-ligament complex, reducing posterior cervical muscle atrophy and improving neck function, without inflicting additional surgical trauma.

Safety and Efficacy of Combined Imbrication Axle Reconstruction and Z-Type Titanium Plate Fixation for Hinge Fracture Displacement During Open-Door Laminoplasty.

BACKGROUND: Open-door laminoplasty is a classical decompression method used to treat cervical spondylotic myelopathy. However, hinge fracture displacement (HFD) is a common occurrence during this procedure. The current study aimed to investigate the safety and efficacy of a combined imbrication axle reconstruction and Z-type titanium plate fixation method for HFD during open-door laminoplasty. METHODS: In total, 617 patients with cervical spondylotic myelopathy who underwent C3-C7 open-door laminoplasty from March 2015 to October 2018 were included in this retrospective study. Overall, 73 patients developed HFD during surgery. Of these, 43 underwent combined imbrication axle reconstruction and Z-type titanium plate fixation (IRZF group) and 30 underwent traditional titanium plate fixation (TF group). Data such as the operative time, intraoperative blood loss volume, and distribution of fractured hinges were recorded. Both groups were compared in terms of improvement in neurologic function, cervical curvature index, hinge fusion rate, incidence of C5 palsy, severity of axial symptoms, and development of complications. RESULTS: The operative time and intraoperative blood loss were slightly higher in the IRZF group than in the TF group; however, the differences were not significant (p > 0.05). Furthermore, there was no significant difference between the groups in terms of the number of fractured segments and the distribution of fractured hinges (p > 0.05). The cervical curvature index did not decline in the two groups (p > 0.05). The IRZF group had a higher hinge fusion rate than the TF group at 3 (79.6 vs. 57.1%) and 12 (93.9 vs. 74.3%) months postoperatively (p < 0.05). There was no significant difference in the incidence of C5 palsy between the two groups (9.3 vs. 6.7%; p > 0.05). However, the TF group had more severe axial symptoms than the IRZF group (p < 0.05). The neurologic function of the two groups increased postoperatively as per the Japanese Orthopaedic Association scoring system (p < 0.05). Nevertheless, there was no significant difference in terms of neurologic function at any observational time point (p > 0.05). One patient in the TF group with hinge nonunion underwent laminectomy due to lamina displacement into the spinal canal and nerve root compression. CONCLUSION: In patients with HFD, IRZF facilitates a more intimate contact between the lamina and the lateral mass and, therefore, achieves fractured hinge fusion without additional surgical trauma. This technical improvement can significantly promote neurologic recovery, decrease the severity of axial symptoms, and prevent the development of spinal cord or nerve root recompression.

Influence of fixed titanium plate position on the effectiveness of open-door laminoplasty for cervical spondylotic myelopathy.

BACKGROUND: During open-door laminoplasty, the position of the bone gutter is not fixed, and when the gutter migrates inward, the outer end of the titanium plate must be fixed on the lamina edge. It is unclear whether this will affect the clinical efficacy. This study aimed to observe the influence of the titanium plate fixation position on the effectiveness of open-door laminoplasty for cervical spondylotic myelopathy (CSM). METHODS: A total of 98 patients with CSM who underwent open-door laminoplasty from August 2016 to October 2019 were included in this retrospective study. Fifty-five patients had the titanium plate fixed on the lateral mass (lateral mass group), and 43 patients had the titanium plate fixed on the lamina edge (lamina group). The opening angle, opening width, occurrence of hinge fracture, spinal cord drift distance, cervical curvature index (CCI), neurological function recovery (JOA score), neck function (NDI), C5 palsy and severity of axial symptoms were observed and compared between the two groups. RESULTS: The opening angle in the lamina group was significantly larger than that in the lateral mass group, while the opening width and the spinal cord drift distance were significantly smaller than those in the lateral mass group (P < 0.05). The occurrence of hinge fracture in the lamina group was significantly higher than that in the lateral group (25.6% and 9.1%, respectively) (P < 0.05). The CCI was maintained well in both groups (P > 0.05), and there was no significant difference between the groups (P > 0.05). After surgery, the JOA score significantly increased in both groups (P < 0.05), and the neurological recovery rates were similar between the two groups (62.6% vs. 64.5%). The NDI score significantly decreased in both groups (P < 0.05), but the lateral mass group recovered to a greater degree than the lamina group (P < 0.05). The occurrence of C5 palsy was 2.3% in the lamina group and 14.5% in the lateral mass group, and there was a significant difference between the groups (P < 0.05). Postoperative axial symptom severity was significantly worse in the lamina group than in the lateral mass group (P < 0.05). CONCLUSIONS: In open-door laminoplasty, it is feasible to fix the titanium plate on the lateral mass or to the lamina due to the same neurological function recovery. However, fixing it to the lamina will increase the opening angle and decrease the opening width, making the hinge prone to fracture and increasing the severity of postoperative axial symptoms.