Objective:To compare the efficacy of laminoplasty via the intermuscular approach or posterior midline approach for treating spinal cord injury without radiographic abnormality (SCIWORA).Methods:A multi-center retrospective cohort study was conducted to analyze the clinical data of 135 patients with SCIWORA admitted to Honghui Hospital Affiliated to Xi'an Jiaotong University School of Medicine, Xi'an No.5 Hospital, Henan Provincial People's Hospital, Zhengzhou Orthopedic Hospital, Xuanwu Hospital of Capital Medical University from February 2021 to June 2023, including 75 males and 60 females, aged 35-78 years [(55.3±8.1)years]. The injury segments involved C 3-C 6. All the patients underwent posterior cervical open-door laminoplasty, among whom 70 patients were treated via the intermuscular approach (intermuscular group) and 65 via the posterior midline approach (posterior midline group). The operation duration, intraoperative blood loss, postoperative drainage volume, and length of hospital stay were recorded. The visual analogue scale (VAS) score, Japanese Orthopedic Association (JOA) score, neck disability index (NDI), Barthel index, cervical Cobb angle, and cervical range of motion (ROM) were measured preoperatively, at 3, 6, 12 months postoperatively and at the final follow-up. The American Spinal Injury Association (ASIA) scale was evaluated preoperatively, at 3, 12 months postoperatively and at the final follow-up. The postoperative complication rate was recorded as well. Results:All the patients were followed up for 15-19 months [(16.3±1.6)months]. The operation duration, intraoperative blood loss, postoperative drainage and length of hospital stay were (125.0±23.0)minutes, (210.4±34.8)ml, and (165.3±23.7)ml, and (5.3±0.1)days in the intermuscular group, which were significantly shorter or less than (168.0±27.6)minutes, (260.2±45.3)ml, (196.4±31.6)ml, and (6.4±0.2)days in the posterior midline group ( P<0.01). The preoperative VAS score, JOA score, NDI and Barthel index showed no significant differences between the two groups ( P>0.05). The VAS score and JOA score also showed no significant differences between the two groups at 3, 6, 12 months postoperatively or at the final follow-up ( P>0.05). The NDI and Barthel index also showed no significant differences between the two groups at 3 months postoperatively ( P>0.05). At 6, 12 months postoperatively and at the final follow-up, the NDI were (15.4±2.5)points, (11.8±2.1)points and (8.6±1.5)points in the intermuscular group, significantly lower than (19.1±3.4)points, (14.3±2.4)points and (11.9±1.4)points in the posterior midline group ( P<0.01). At 6, 12 months postoperatively and at the final follow-up, the Barthel index were (71.4±6.2)points, (83.4±5.8)points and (89.2±7.1)points in the intermuscular group, significantly higher than (59.6±4.7)points, (74.2±3.9)points and (78.8±6.2)points in the posterior midline group ( P<0.01). Both groups showed significant improvements in VAS score, JOA score, NDI and Barthel index at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05). Among them, the VAS score, NDI and Barthel index were further improved over time ( P<0.05). Simultaneously, the JOA score was significantly improved at 6, 12 months postoperatively and at the last follow-up when compared to that at 3 months postoperatively ( P<0.05), with no significant difference at later time points between the two groups ( P>0.05). The preoperative cervical Cobb angle and ROM showed no significant differences between the two groups ( P>0.05). There was no significant difference in the Cobb angle between the two groups at 3, 6 or 12 months postoperatively ( P>0.05), while it was (13.6±2.4)° in the intermuscular group at the final follow-up, significantly larger than (10.4±2.8)° in the posterior midline group ( P<0.01). At 3, 6, 12 months postoperatively and at the final follow-up, the cervical ROM were (34.1±6.4)°, (32.6±7.3)°, (31.8±9.1)° and (29.6±8.7)° in the intermuscular group, significantly larger than (23.7±8.3)°, (22.3±7.8)°, (22.5±8.1)° and (20.6±9.3)° in the posterior midline group ( P<0.01). In the intermuscular group, the cervical Cobb angle showed no significant changes at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P>0.05). In the posterior midline group, the Cobb angles were significantly reduced at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decrease at 12 months postoperatively and at the final follow-up from those at 3, 6 months postoperatively ( P<0.05), no significant difference at 6 months postoperatively from that at 3 months postoperatively ( P>0.05), and significant decrease at the final follow-up from that at 12 months postoperatively ( P>0.05). In the intermuscular group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively and showed further improvement over time ( P<0.05). In the posterior midline group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decreases at 6, 12 months postoperatively and at the final follow-up from that at 3 months postoperatively ( P<0.05), significant decreases at the final follow-up from those at 6, 12 months postoperatively ( P<0.05), and no significant difference at 12 months postoperatively from that at 6 months postoperatively ( P>0.05). The ASIA grades showed no significant difference between the two groups preoperatively, at 3, 12 months postoperatively and at the final follow-up ( P>0.05) , but were gradually improved over time in both groups ( P<0.05). The postoperative complication rate was 9%(6/70) in the intermuscular group, significantly lower than 48%(31/65) in the posterior midline group ( P<0.01). Conclusion:Compared to the posterior midline approach, the intermuscular approach for laminoplasty in patients with SCIWORA possesses advantages, including shorter operative time and length of hospital stay, reduced intraoperative blood loss and postoperative drainage, less postoperative neck disability, higher daily life quality, better long-term preservation of cervical lordosis and motion, and a lower complication rate.

Objective:To compare the efficacy of laminoplasty via the intermuscular approach or posterior midline approach for treating spinal cord injury without radiographic abnormality (SCIWORA).Methods:A multi-center retrospective cohort study was conducted to analyze the clinical data of 135 patients with SCIWORA admitted to Honghui Hospital Affiliated to Xi'an Jiaotong University School of Medicine, Xi'an No.5 Hospital, Henan Provincial People's Hospital, Zhengzhou Orthopedic Hospital, Xuanwu Hospital of Capital Medical University from February 2021 to June 2023, including 75 males and 60 females, aged 35-78 years [(55.3±8.1)years]. The injury segments involved C 3-C 6. All the patients underwent posterior cervical open-door laminoplasty, among whom 70 patients were treated via the intermuscular approach (intermuscular group) and 65 via the posterior midline approach (posterior midline group). The operation duration, intraoperative blood loss, postoperative drainage volume, and length of hospital stay were recorded. The visual analogue scale (VAS) score, Japanese Orthopedic Association (JOA) score, neck disability index (NDI), Barthel index, cervical Cobb angle, and cervical range of motion (ROM) were measured preoperatively, at 3, 6, 12 months postoperatively and at the final follow-up. The American Spinal Injury Association (ASIA) scale was evaluated preoperatively, at 3, 12 months postoperatively and at the final follow-up. The postoperative complication rate was recorded as well. Results:All the patients were followed up for 15-19 months [(16.3±1.6)months]. The operation duration, intraoperative blood loss, postoperative drainage and length of hospital stay were (125.0±23.0)minutes, (210.4±34.8)ml, and (165.3±23.7)ml, and (5.3±0.1)days in the intermuscular group, which were significantly shorter or less than (168.0±27.6)minutes, (260.2±45.3)ml, (196.4±31.6)ml, and (6.4±0.2)days in the posterior midline group ( P<0.01). The preoperative VAS score, JOA score, NDI and Barthel index showed no significant differences between the two groups ( P>0.05). The VAS score and JOA score also showed no significant differences between the two groups at 3, 6, 12 months postoperatively or at the final follow-up ( P>0.05). The NDI and Barthel index also showed no significant differences between the two groups at 3 months postoperatively ( P>0.05). At 6, 12 months postoperatively and at the final follow-up, the NDI were (15.4±2.5)points, (11.8±2.1)points and (8.6±1.5)points in the intermuscular group, significantly lower than (19.1±3.4)points, (14.3±2.4)points and (11.9±1.4)points in the posterior midline group ( P<0.01). At 6, 12 months postoperatively and at the final follow-up, the Barthel index were (71.4±6.2)points, (83.4±5.8)points and (89.2±7.1)points in the intermuscular group, significantly higher than (59.6±4.7)points, (74.2±3.9)points and (78.8±6.2)points in the posterior midline group ( P<0.01). Both groups showed significant improvements in VAS score, JOA score, NDI and Barthel index at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05). Among them, the VAS score, NDI and Barthel index were further improved over time ( P<0.05). Simultaneously, the JOA score was significantly improved at 6, 12 months postoperatively and at the last follow-up when compared to that at 3 months postoperatively ( P<0.05), with no significant difference at later time points between the two groups ( P>0.05). The preoperative cervical Cobb angle and ROM showed no significant differences between the two groups ( P>0.05). There was no significant difference in the Cobb angle between the two groups at 3, 6 or 12 months postoperatively ( P>0.05), while it was (13.6±2.4)° in the intermuscular group at the final follow-up, significantly larger than (10.4±2.8)° in the posterior midline group ( P<0.01). At 3, 6, 12 months postoperatively and at the final follow-up, the cervical ROM were (34.1±6.4)°, (32.6±7.3)°, (31.8±9.1)° and (29.6±8.7)° in the intermuscular group, significantly larger than (23.7±8.3)°, (22.3±7.8)°, (22.5±8.1)° and (20.6±9.3)° in the posterior midline group ( P<0.01). In the intermuscular group, the cervical Cobb angle showed no significant changes at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P>0.05). In the posterior midline group, the Cobb angles were significantly reduced at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decrease at 12 months postoperatively and at the final follow-up from those at 3, 6 months postoperatively ( P<0.05), no significant difference at 6 months postoperatively from that at 3 months postoperatively ( P>0.05), and significant decrease at the final follow-up from that at 12 months postoperatively ( P>0.05). In the intermuscular group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively and showed further improvement over time ( P<0.05). In the posterior midline group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decreases at 6, 12 months postoperatively and at the final follow-up from that at 3 months postoperatively ( P<0.05), significant decreases at the final follow-up from those at 6, 12 months postoperatively ( P<0.05), and no significant difference at 12 months postoperatively from that at 6 months postoperatively ( P>0.05). The ASIA grades showed no significant difference between the two groups preoperatively, at 3, 12 months postoperatively and at the final follow-up ( P>0.05) , but were gradually improved over time in both groups ( P<0.05). The postoperative complication rate was 9%(6/70) in the intermuscular group, significantly lower than 48%(31/65) in the posterior midline group ( P<0.01). Conclusion:Compared to the posterior midline approach, the intermuscular approach for laminoplasty in patients with SCIWORA possesses advantages, including shorter operative time and length of hospital stay, reduced intraoperative blood loss and postoperative drainage, less postoperative neck disability, higher daily life quality, better long-term preservation of cervical lordosis and motion, and a lower complication rate.