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Objective: To review the definition and possible etiologies for C 5 palsy., Methods: The literature on C 5 palsy at home and abroad in recent years was extensively reviewed, and the possible etiologies were analyzed based on clinical practice experience., Results: There are two main theories (nerve root tether and spinal cord injury) accounting for the occurrence of C 5 palsy, but both have certain limitations. The former can not explain the occurrence of C 5 palsy after anterior cervical spine surgery, and the latter can not explain that the clinical symptoms of C 5 palsy is often the motor dysfunction of the upper limb muscles. Based on the previous reports, combining our clinical experience and research, we propose that the occurrence of C 5 palsy is mainly due to the instrumental injury of anterior horn of cervical spinal cord during anterior cervical decompression. In addition, the C 5 palsy following surgery via posterior approach may be related to the nerve root tether caused by the spinal cord drift after decompression., Conclusion: In view of the main cause of C 5 palsy after cervical decompression, it is recommended to reduce the compression of the spinal cord by surgical instruments to reduce the risk of this complication.

Purpose: This prospective cohort study reports on a modified technique, namely precise safety decompression via double percutaneous lumbar foraminoplasty (DPLF) and percutaneous endoscopic lumbar decompression (PELD) for lateral lumbar spinal canal (LLSC) stenosis, and its short-term clinical outcomes., Methods: The study analyzed 69 patients with single-level LLSC stenosis simultaneously occurring in both zones 1 and 2 (defined as retrodiscal space and upper bony lateral recess respectively by new LLSC classification) who underwent DPLF-PELD from November 2018 to April 2019. Clinical outcomes were evaluated according to preoperative, 3 months postoperatively, and last follow-up, via leg pain/low back pain (LBP) visual analog scale (VAS) scores, Oswestry disability index (ODI) scores, and the Macnab criteria. The postoperative MRI and CT were used to confirm the complete decompression, and flexion-extension x-rays at the last follow-up were used to observe lumbar stability., Results: All patients successfully underwent DPLF-PELD, and the stenosis was completely decompressed, confirmed by postoperative MRI and CT. The mean follow-up duration was 13 months (range: 8-17 months). The mean preoperative leg pain VAS score is 7.05 ± 1.04 (range 5-9), which decreased to 1.03 ± 0.79(range: 0-3) at 3 months postoperatively and to 0.75 ± 0.63 (range: 0-2) by the last follow-up visit (p < 0.05). The mean preoperative ODI was 69.8 ± 9.05 (range: 52-85), which decreased to 20.3 ± 5.52 (range: 10-35) at the third month postoperatively and to 19.6 ± 5.21 (range: 10-34) by the final follow-up visit (p < 0.05). The satisfactory (excellent or good) results were 94.2%. There was one patient with aggravated symptoms, which were relieved after an open surgery. Two patients had a dural tear, and two patients suffered postoperative LBP. No recurrence or segmental instability was observed at the final follow-up., Conclusion: DPLF-PELD could be a good alternative for the treatment of LLSC stenosis patients whose stenosis occurred in both zones 1 and 2., Trial Registration: Chinese Clinical Trial Registry ( ChiCTR1800019551 ). Registered 18 November 2018.

Background: At present, few reports of percutaneous endoscopic transforaminal decompression surgery have been reported to solve central lumbar spinal stenosis (CLSS). Is endoscopic decompression through bilateral transforaminal approach decompression sufficient for degenerative CLSS?, Methods: This retrospective study included 47 cases of CLSS patients who underwent percutaneous endoscopic decompression through bilateral transforaminal approach. Clinical outcomes such as ODI, back and leg VAS, the Macnab criteria were evaluated. Surgical results including operative time, postoperative hospital stay, recurrence, and surgical complications were also studied. Radiologically, lumbar stability was assessed and lumbar dural sac dimension was compared preoperatively and postoperatively., Results: All 47 patients were followed up. The average follow-up period was 24.5 months. The average operation time was 116 min. The mean VAS of leg and back pain, and the mean ODI improved from 7.81, 2.53, and 77.03% at baseline to a final 1.94 (P = 0.00), 2.47 (P = 0.71), and 19.40% (P = 0.00), respectively. According to the Macnab criteria, 97.9% of patients achieved excellent and good results. There were 2 cases of dural tear and 3 cases of transient postoperative dysthesia. The cross-sectional area of the dural sac was significant enlargement at the last fellow up (74.28 ± 13.08 mm 2 vs.104.91 ± 12.40 mm 2 , P = 0.00)., Conclusions: Except for the main pathogenic factors on the dorsal side of the dural sac, percutaneous endoscopic decompression through a bilateral transforaminal approach is sufficient for CLSS. It is a feasible, safe, and clinically effective minimally invasive procedure.

Objective: To assess the reliability, effectiveness, and the safety of full endoscopic transforaminal decompression (FETD) under local anesthesia guided by the classification of lateral region of the lumbar spinal canal (CLLSC) in treating lumbar spinal stenosis (LSS) in geriatric patients., Methods: The clinical data of 63 geriatric patients with LSS met the inclusion criteria underwent FETD surgery between June 2015 and July 2017 were retrospectively analyzed. There were 37 males and 26 females, with a median age of 76 years [interquartile range (IQR), 73-80 years], and a median symptomatic duration of 55 months (IQR, 16-120 months). There were 17 cases of grade B and 46 cases of grade C based on the Schizas morphological grading system. CLLSC was used for imaging evaluation for the stenotic condition, and intra-class correlation coefficients (ICC) were used to test intra-observer and inter-observer reliability of CLLSC. The stenotic condition of patients was re-evaluated by the surgeon after operation, and the results were compared with the findings of preoperative CLLSC. The visual analogue scale (VAS) score for low back pain and leg pain recorded before operation, and at 1 day, 3 months, and 6 months after operation, and last follow-up were used to assess the pain relieving; the functional improvement was evaluate by Oswestry disability index (ODI); the modified Macnab criteria were used to self-evaluate the surgical satisfaction., Results: The operation were successfully performed for all patients, with a median operation time of 75 minutes (IQR, 65-85 minutes), postoperative hospitalization stay of 48 hours (IQR, 48-72 hours), and the time to ambulation after operation of 24 hours (IQR, 24-24 hours). Sixty-three patients were followed-up and with a median follow-up time of 18 months (IQR, 13-20 months). Based on preoperative CLLSC classification, there were 72 stenotic zones, distributed 16 in zone 1, 6 in zone 2, 3 in zone 3, 2 in zone 4, 7 in zone 5, 34 in zones 1+2, 2 in zones 3+4, and 2 in zones 4+5. Perioperative complications occurred in 4 cases (6.3%), including 2 cases of intraoperative dural sac tear, 1 of preoperative numbness symptom aggravation, and 1 of postoperative urinary retention. VAS score of leg pain and ODI score at each time point after operation were significantly improved compared with those before operation ( P <0.05). VAS scores of low back pain showed no significant difference between pre- and post-operation ( P >0.05). At last follow-up, based on the modified Macnab criteria, 19 cases were excellent, 37 were good, 6 were fair, and 1 was poor, and the excellent and good rate was 88.9%. The reliability analysis showed that CLLSC had substantial intra-observer reliability in the geriatric population, with an average ICC of 0.78. There was also a substantial inter-observer reliability, with an average ICC of 0.73. While comparing the preoperative CLLSC results with the postoperative CLLSC results, 53 patients (73.6%) were in full agreement, 15 patients (20.8%) were in partial agreement, and 4 patients (5.6%) were not., Conclusion: CLLSC has high reliability in the diagnosis of LSS in the geriatric patients. Combined FETD with CLLSC, accurate diagnosis, and minimal invasion can be performed to achieve safe and effective result.

Purpose: To define and analyze the learning curve of percutaneous endoscopic transforaminal decompression (PETD) for lumbar spinal stenosis (LSS)., Methods: From July 2015 to September 2016, 78 patients underwent PETD; one of whom was converted to open surgery, two were lost, and 75 were included in this study. Clinical results were assessed by using the Oswestry Disability Index (ODI) and visual analog scale (VAS). The learning curve was assessed by a logarithmic curve-fitting regression analysis. Of these 75 patients, 35 were defined as the "early" group, and 40 were defined as the "late" group for comparison., Results: The mean follow-up was 25.37 ± 4.71 months. The median operative time gradually decreased from 95 (interquartile range, IQR, 85-110) minutes for the early group to 70 (IQR, 60-80) minutes for the late group (P < .000), and an asymptote was reached after approximately 35 cases. After surgery, the VAS for leg pain (LP) and ODI decreased significantly and remained constant during the follow-up. However, the VAS of low back pain (LBP) increased mildly. The total complication rate was 6.6%. ODI, VAS of LP and of LBP, and complication rate did not significantly differ between two groups. Early ambulation and short hospital stay after surgery were achieved., Conclusion: The learning curve of PETD for LSS was assessed and good clinical results were achieved. The surgeon's experience with this technique correlated with reduced operation time. Proper patient selection, familiarity with pathological anatomy, and manipulation under endoscopic view may shorten the learning curve and decrease complications.

Objective: To explore the effect and safety of transforaminal percutaneous endoscopic decompression for lower thoracic spinal stenosis., Methods: We reviewed 6 patients receiving transforaminal percutaneous endoscopic thoracic decompression for sympathetic symptoms in the lower extremities. Pre- and postoperative Frankel grade and Japanese Orthopaedic Association scale (JOA) score, Oswestry Disability Index (ODI) score, and visual analog scale (VAS) scores of back and lower extremities were also evaluated and recorded. Wilcoxon signed-rank test was performed for statistical analysis., Results: All 6 patients completed the follow-up. Mean follow-up was 12.6 months. Frankel grade in all patients improved to normal at the third month after operation. JOA scores significantly increased from 4.4 (range, 3.5-5.0) preoperatively to 5.5 (range, 5.0-6.5) postoperatively, to 6.5 (range, 6.0-7.0) at 3 months, to 6.6 (range, 6.2-7.0) at 6 months, and to 6.6 (range, 6.2-7.1) at 12 months (P < 0.05). ODI scores significantly decreased from 71.2 (range, 65-78) preoperatively to 50.2 (range, 45-60) postoperatively, to 30.3 (range, 25-40) at 3 months, to 12.2 (range, 0-20) at 6 months, and to 10.2 (range, 0-15) at 12 months (P < 0.05). VAS back scores decreased from 7.8 (range, 7.0-9.0) preoperatively to 6.9 (range, 6.0-7.5) postoperatively, to 3.3 (range, 3.0-4.0) at 3 months, to 2.3 (range, 2.0-3.0) at 6 months, and to 1.9 (range, 1.5-3.0) at 12 months (P < 0.05). VAS lower extremity scores decreased from 8.7 (range, 8.0-9.0) preoperatively to 3.0 (range, 2.5-3.6) postoperatively, to 1.1 (range, 0.5-1.3) at 3 months, to 0.9 (range, 0.2-1.2) at 6 months, and to 0.3 (range, 0.1-1.0) at 12 months (P < 0.05). Four patients reported excellent results and 2 reported good results at the last follow-up., Conclusions: Percutaneous endoscopic transforaminal thoracic decompression is effective and safe in settling lower thoracic spinal stenosis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Recently, full endoscopic transforaminal decompression surgery (FETDS) under local anesthesia has been used to treat symptomatic lumbar spinal stenosis (SLSS) in selective patients. Considering the minimal injury associated with this technique, it has a potential advantage for geriatric patients. In addition, combining thorough preoperative assessments and preparations with this technique to achieve a safer and more effective outcome for geriatric patients with SLSS is necessary., Methods: Between June 2015 and September 2016, after thorough preoperative assessments and preparations, 56 geriatric patients who underwent FETDS with a median 18 months follow-up were enrolled in this study. Clinical results were assessed using the Oswestry Disability Index, visual analog scale (VAS), and the modified Macnab criteria., Results: The median duration of surgery was 75 minutes. The mean VAS score for preoperative leg pain was 6.54 ± 0.66, which improved to 1.79 ± 0.80, 1.50 ± 0.79, 1.43 ± 0.85, and 1.39 ± 0.97 after surgery, at 3 months, at 6 months, and at the last follow-up, respectively. The mean VAS score for preoperative low back pain was 2.00 ± 1.01, which changed to 2.09 ± 0.79, 2.07 ± 0.83, 2.09 ± 0.92, and 2.23 ± 0.76 at the same evaluation times, respectively. The mean preoperative Oswestry Disability Index was 69.30 ± 6.07, which improved to 22.36 ± 8.35, 22.32 ± 8.47, 22.21 ± 6.61, and 24.57 ± 8.23, respectively. The modified Macnab criteria were consistent with excellent or good outcomes in 91.1% of patients. Three patients (5.4%) developed complications., Conclusions: FETDS was effective and safe in the treatment of SLSS in geriatric patients, with minimal physiologic impact, taking advantage of the current protocol of thorough assessments and appropriate preoperative preparation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: To study whether and when mere dorsal decompression is enough in the full endoscopic key hole technique for foraminal stenosis., Methods: We retrospectively reviewed a total of 22 patients with cervical foraminal stenosis who underwent full endoscopic key hole mere dorsal decompression in our institute from October 2016 to October 2017., Results: Preoperative neck disability index, neck visual analog scale score, and arm visual analog scale score were 25.8 ± 0.8, 4.9 ± 0.6, and 7.5 ± 0.5 in the group. Immediate postoperative scores were 6.9 ± 0.9, 1.3 ± 0.9, and 1.4 ± 0.5. Follow-up scores at 3 months (7.0 ± 0.9, 1.9 ± 0.6, and 2.7 ± 0.9), 6 months (7.3 ± 0.9, 2.1 ± 0.9, and 1.9 ± 0.5), and 12 months (7.6 ± 0.5, 2.5 ± 0.8, and 2.1 ± 0.7). The symptoms had improved significantly (P < 0.05). According to the Macnab criteria, 15 patients reported excellent results, 2 reported good results, and 2 reported fair results at the 12-month follow-up., Conclusions: Stenosis is mainly caused by dorsal structures; mere dorsal decompression is enough. In both cases, the ventral and dorsal structures contributed to the stenosis. When there is no herniated soft fragment contributing to the stenosis, ventral decompression is not always necessary. If intraoperative exploration detects less tension formed by the ventral abnormal structures, mere dorsal decompression is enough to settle the symptoms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: The purpose of the present study was to provide a new classification of the lateral region of the lumbar spinal canal (LLSC) and evaluate the clinical outcomes of surgical treatment of LLSC stenosis guided by the classification., Methods: We developed a new functional classification of the LLSC by dividing the region into 5 zones. Thirty random lumbar imaging studies from patients with single-level LLSC stenosis in our department from January 2015 to June 2015 were evaluated by 3 examiners to validate its reliability. Subsequently, a prospective clinical outcome study of 76 patients with single-level LLSC stenosis from July 2015 to July 2016 with 2-year follow-up available was undertaken. All the patients had undergone either percutaneous endoscopic transforaminal decompression with foraminoplasty or percutaneous endoscopic interlaminar decompression, according to the classification. The clinical outcomes were evaluated using MacNab criteria, and pre- and postoperative leg pain were evaluated using the visual analog scale., Results: We observed a 93.3% agreement among examiners. The mean follow-up duration was 15.6 months (range, 3-24). We found good and excellent outcomes in 93.4% of the patients at the last follow-up examination. The mean preoperative visual analog scale score was 5.72 ± 1.18 (range, 4-9), which had decreased to 1.26 ± 0.81 (range, 0-3) at the third month postoperatively and to 0.78 ± 0.62 (range, 0-1) by the last follow-up visit. Dural tears appeared in 2 patients, and migrated bone had moved into the spinal canal after the surgery in 1 patient., Conclusions: The new classification of LLSC can provide objective criteria for full-endoscopic surgery that could lead to better clinical outcomes., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To discuss the effectiveness and the safety of accurate decompression via foraminoplasty in treating lumbar lateral recess stenosis patients who accompanied by disk-flavum ligamentum space and bony lateral recess stenosis, and to analysis the short-term effectiveness of the surgical procedures., Methods: Forty-five lumbar lateral recess stenosis patients accompanied by disk-flavum ligamentum space and bony lateral recess stenosis were treated by accurate decompression via foraminoplasty between January 2013 and January 2016. There were 29 males and 16 females with a median age of 58 years (range, 42-82 years). The disease duration was 3-96 months (mean, 24.4 months). The lesion segment included L 4, 5 in 36 cases and L 5 , S 1 in 9 cases. The visual analogue scale (VAS) score of low back pain and leg pain at preoperation and last follow-up were recorded, and the modified Macnab criteria was used to evaluate the effectiveness at last follow-up. Postoperative CT and MRI were reviewed to evaluate the stability and decompression of the lumbar spine., Results: All operations were successfully completed. All the 45 patients were followed up 3-18 months (median, 11 months). Dural tear occurred in 2 cases during operation, bone graft removed into the spinal canal in 1 case, postoperative low back pain occurred in 5 cases, and there was no nerve root injury, hematoma formation, or other complications. The leg pain VAS score at last follow-up (0.6±1.2) was significantly improved when compared with preoperative score (5.7±1.4) ( t =8.981, P =0.001); and the low back pain VAS scores showed no significant difference between preoperation and last follow-up (1.5±1.3 vs. 1.7±1.4; t =0.535, P =0.585). According to the modified Macnab criteria, the results were excellent in 20 cases, good in 22 cases, fair in 2 cases, and poor in 1 case at last follow-up, and the excellent and good rate was 93.3%., Conclusion: Accurate decompression via foraminoplasty is an effective, safe, and less invasive way for treating lumbar recess stenosis patients accompanied by disk-flavum ligamentum space and bony lateral recess stenosis.

Objective: To investigate the technique of reduction by posterior approach for severe spondylolisthesis, and to discuss the method to prevent nerve stretch injury., Methods: Between July 2007 and April 2011, 17 patients with severe spondylolisthesis underwent reduction, fixation, and fusion by posterior approach. There were 2 males and 15 females with a median age of 15 years (range, 8-67 years) and a median disease duration of 18 months (range, 5 months-16 years and 4 months). The level of spondylolisthesis was at L4 in 1 case and Ls in 16 cases; the spondylolisthesis was at degree III in 12 cases and degree IV in 5 cases according to Meyerding classification. There were 16 cases of developmental spondylolisthesis (high-dysplastic and low-dysplasia spondylolisthesis in 9 and 7 cases, respectively) and 1 case of traumatic spondylolisthesis; 16 cases of developmental spondylolisthesis at L5 level included 6 cases of type 4, 9 case of type 5, and 1 case of type 6 according to Spinal Deformity Study Group (SDSG) classification. All cases underwent posterior spinal decompression, Schanz screw fixation for the slipped vertebrae, the intervertebral and posterolateral fusion and reduction of the slipped vertebrae, and correction of the lumbosacral kyphosis. The reductive degree of slipped vertebrae was modulated according to the strain of exiting spinal root. The slip degree should be reduced within Meyerding degree II. The anteroposterior and lateral radiographs of whole spine were taken in a standardized standing position to observe the correction of displacement severity and lumbosacral angle. The nerve function and pain score of lower extremity were evaluated by neurological Frankel grade and visual analogue scale (VAS). Bony fusion was assessed by followed-up CT three-dimentional reconstruction. Results Exiting nerve root paralysis occurred in 1 case after operation, and released at 4 weeks after operation; no aggravation of nerve damage was observed in the other patients. The incisions primarily healed. All the patients were followed up 12-48 months (mean, 25 months). The slip percentage, the lumbosacral angle, and VAS score of lower extremity were improved from 72% +/- 10%, (18.2 +/- 3.5) degrees, and 7.0 +/-1.5 at preoperation to 12% +/- 6%, (-7.3 +/- 2.9) degrees , and 1.5 + 1.3 at 12 months after operation respectively, all showing significant differences (P < 0.05). Osteosynthesis was seen at the bone grafting area by CT three-dimentional reconstruction at 12 months after operation. No breakage of screw and rod or reduction loss occurred., Conclusion: It can obtain satisfactory clinical result to use spinal canal decompression by posterior approach, the Schanz screw fixation of the slipped vertebrae, the intervertebral and posterolateral fusion for severe spondylolisthesis. The risk of nerve stretch injury can be prevented by choosing the lowest height of intervertebral cage, modulating the reductive degree of slipped vertebrae according to the strain of exiting spinal root, and correcting lumbosacral kyphosis.

Objective: To compare the short-term effectiveness of minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) versus open-TLIF in treatment of single-level lumbar degenerative disease., Methods: Between February 2010 and February 2011, 147 patients with single-level lumbar degenerative diseases underwent open-TLIF in 104 cases (open-TLIF group) and MIS-TLIF in 43 cases (MIS-TLIF group), and the clinical data were analyzed retrospectively. There was no significant difference in gender, age, disease type, lesion level, disease duration, preoperative visual analogue scale (VAS), and preoperative Oswestry disability index (ODI) between 2 groups (P > 0.05). The operation time, intraoperative radiological exposure time, intra- and post-operative blood loss, postoperative hospitalization time, and postoperative complications were compared between 2 groups. The VAS score and ODI were observed during follow-up. The imaging examination was done to observe the bone graft fusion and the locations of internal fixator and Cage., Results: There was no significant difference in operation time between 2 groups (t = 0.402, P = 0.688); MIS-TLIF group had a decreased intra- and post-operative blood loss, shortened postoperative hospitalization time, and increased intraoperative radiological exposure time, showing significant differences when compared with open-TLIF group (P < 0.05). Cerebrospinal fluid leakage (2 cases) and superficial infection of incision (2 cases) occurred after operation in open-TLIF group, with a complication incidence of 3.8% (4/104); dorsal root ganglion stimulation symptom (3 cases) occurred in MIS-TLIF group, with a complication incidence of 7.0% (3/43); there was no significant difference in the complication incidence between 2 groups (chi2 = 0.657, P = 0.417). The patients were followed up 18-26 months (mean, 21 months) in MIS-TLIF group, and 18-28 months (mean, 23 months) in open-TLIF group. The VAS scores and ODI of 2 groups at each time point after operation were significantly improved when compared with those before operation (P < 0.05). There was no significant difference in VAS score between 2 groups at discharge and 3 months after operation (P > 0.05); VAS score of MIS-TLIF group was significantly lower than that of open-TLIF group at last follow-up (t = 2.022, P = 0.047). At 3 months and last follow-up, no significant difference was found in the ODI between 2 groups (P > 0.05). The imaging examination showed good positions of Cage and internal fixator, and bone graft fusion in 2 groups., Conclusion: The shortterm effectiveness of MIS-TLIF and open-TLIF for single-level degenerative lumbar diseases was similar. MIS-TLIF has the advantages of less invasion and quick recovery, but the long-term effectiveness needs more observation.

Study Design: A series study of patients with lower cervical facet dislocation accompanied by traumatic disc herniation treated with anterior decompression and nonstructural bone grafting and posterior fixation., Objective: To describe a surgical technique of anterior decompression and nonstructural bone grafting and posterior fixation and its clinical outcome in a group of patients with lower cervical facet dislocation accompanied by traumatic disc herniation., Summary of Background Data: The optimal treatment for lower cervical facet dislocation with a prolapsed disc is still controversial., Methods: After discectomy and endplate preparation, a layer of morselized cancellous bone grafts from the iliac crest was placed in the interspace, and held in appropriate sagittal position by 2 layers of gelatin sponge and carefully sutured longus colli muscle. The anterior wound was then closed. The posterior elements were exposed and the reduction was performed. Fluoroscopy was used during reduction maneuver to ensure that the graft was still in the appropriate position. A posterior fusion was performed and the posterior wound was closed., Results: Between January 2006 and February 2010, 21 patients with cervical facet dislocation accompanied by traumatic disc herniation (13 unilateral dislocations and 8 bilateral dislocations) were recruited for this study. All the patients completed at least 1-year follow-up. Average follow-up duration was 29 ± 3.5 months. Average Frankel scales were significantly improved at the end of follow-up, visual analogue scale decreased from 7.8 ± 1.2 before the operation to less than 1.6 ± 0.5 (P < 0.05) 6 months later. Kyposis was corrected from 17.7° ± 6.3° to 6.5° ± 4.1° (P < 0.05) and remained at 5.9° ± 4.2° (P > 0.05) 1 year later. The average subsidence of bone graft was 1.28 ± 0.16 mm at 12 months after the operation and remained 1.34 ± 0.20 mm at 36 months after the operation. All patients had consolidation of both anterior and posterior fusions. No cases of instrument failure occurred and no complications were attributed to the use of this technique., Conclusion: Although further study based on injury types as well as long-term follow-up is still needed, anterior decompression and nonstructural bone grafting and posterior fixation provides a promising surgical option for treating cervical facet dislocation with traumatic disc herniation.

Study Design: A retrospective study to analyze the effect of decompressive extent on the posterior shift of spinal cord after expansive open-door laminoplasty (ELAP)., Objective: To investigate the effect of decompressive extent on cord shift distance after ELAP, and determine the morphologic limitations of posterior approach when the cervical alignment is lordotic or straight., Summary of Background Data: It is still controversial on the effect of space available for spinal cord at the level cephalad to the decompression with cord shift. Moreover, there is less understanding regarding the significance of decompressive extent of laminoplasty in relation to spinal cord shift and clinical outcome., Methods: Preoperative and postoperative MRIs of 76 patients with a straight or lordotic cervical spine who had undergone cervical laminoplasty were reviewed and evaluated retrospectively. Radiographic parameters including cervical sagittal alignment, space available at the level cephalad, the thickness of compressive mass, and the average anterior subarachnoid space were measured. Laminoplasty was performed from C1 to C7 in 11 cases (CI group), C2 to C7 in 30 cases (CII group), and C3 to C7 in 35 cases (CIII group). According to whether the anterior indirect decompression was adequate or not, CII and CIII groups were further divided into two subgroups, the noncontact group in which the spinal cord was completely separated from the anterior compressive mass after laminoplasty, and the contact group in which there was residual cord compression after laminoplasty. The recovery rate that based on the Japanese Orthopedic Association score was calculated for each patient., Results: There were statistically significant differences in the average anterior subarachnoid space among CI, CII, and CIII groups (P < 0.05);the average anterior subarachnoid space was the largest in CI group, and the smallest in CIII group. The space available at the level cephalad had strong sigmoidal correlation with cord postoperative shift in CIII group (R = 0.91). A higher neurologic recovery rate (69% ± 20% vs. 29% ± 11%; P < 0.05) in the noncontact group after surgery than in the contact group, with a similar follow-up period., Conclusion: The posterior decompression extent is a main factor affecting cord shift distance after laminoplasty in the context of a straightened or lordotic cervical curvature. The space available at the levels cephalad is a key factor to predict cord shift distance in laminoplasty from C3 to C7. Neurologic recovery rate after ELAP is affected by whether the anterior indirect decompression was adequate or not.