Comparison of anterior cervical fusion after two-level discectomy or single-level corpectomy: sagittal alignment,cervical lordosis,graft collapse,and adjacent-level ossification

Background contextSingle-level corpectomy and two-level discectomy with anterior cervical plating have been reported to have comparable fusion and complication rates. However, there are few large series that have compared the two for sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification.PurposeTo determine the differences between these two procedures for patients with two-level spondylosis by comparing the pre- and postoperative radiographic data.Study designRetrospective review of prospectively collected data in an academic institution.Patient sampleFifty-two with a single-level corpectomy and 45 with a two-level anterior cervical discectomy and fusion (ACDF).Outcome measuresPre- and postoperative radiographic data for sagittal alignment, cervical lordosis, subsidence, and adjacent-level ossification.MethodsWe retrospectively reviewed the lateral cervical radiographs of patients who had a solid fusion after a single-level cervical corpectomy or a two-level ACDF for the treatment of a degenerative cervical spondylosis by a surgeon at an academic institution. The choice of the operation was dependent on the presence or absence of retrovertebral compression. All patients underwent anterior cervical fusion using fibula strut allograft and variable-angle screw-plate fixation. None had had prior cervical spine surgery. Twenty-five were excluded because of inadequate radiographs and follow-up. There were 52 with a single-level corpectomy and 45 with a two-level ACDF. The following were analyzed: 1) sagittal alignment (modified method of Toyama); 2) cervical lordosis measured by Cobb angles of fusion constructs (fusion Cobb) and C2–C7 (C2–C7 Cobb); 3) graft collapse determined by the subsidence of anterior/posterior body height of fused segments (anterior/posterior subsidence) and the cranial/caudal plate-to-disc distances (cranial/caudal subsidence), and the difference between anterior and posterior body height for the fused levels (anteroposterior [AP] difference); and 4) the severity of ossification at two adjacent levels.ResultsThe mean durations of follow-up were 23.3±6.6 (corpectomy) and 25.7±6.2 (ACDF) months, range 12 to 45 months. There were no significant differences between the two groups in sagittal alignment, cervical lordosis, graft collapse, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis occurred significantly more during the first 6 weeks after surgery (all measurements, p<.0001) than after 6 weeks, with no significant difference between the two groups. Posterior and caudal end plate subsidence significantly progressed after 6 weeks in Group 1 (p=.04, p=.02). The final follow-up Cobb angle positively correlated with preoperative and immediate postoperative Cobb angles (r=0.437, p<.0001; r=0.727, p<.0001), caudal subsidence (r=0.270, p=.008), and the final AP difference (r=0.915, p<.0001) but did not correlate with surgery level, preoperative and final sagittal alignments, anterior/posterior subsidence, and cranial subsidence. Anterior/posterior subsidence was significantly more strongly related with caudal subsidence (r=0.607, p<.0001; r=0.424, p<.0001) than cranial (r=0.277, p=.007; r=0.211, p=.040) but did not correlate with pre- and postoperative fusion Cobb, and preoperative and the last sagittal alignments.ConclusionsOur data suggest that the two procedures yield comparable results in terms of sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis appeared to occur mainly during the first 6 weeks after surgery. Single-level corpectomy and fusion continued to subside at the posterior portion of caudal end plate even after 6 weeks. On the other hand, graft subsidence did not correlate with preoperative and final postoperative sagittal alignments.     

Microsurgical posterior herniotomy with en bloc laminoplasty: alternative method for treating cervical disc herniation

OBJECTIVE: At the present time, the anterior cervical discectomy and fusion procedure is widely accepted for treating cervical disc herniation. Recently, however, several authors have reported new disease due to degeneration of an adjacent segment. On the other hand, posterior discectomy, which can preserve mobility at the affected disc level, has been considered risky and technically difficult, especially for central or paracentral disc herniation. We are performing a new surgical technique, microsurgical posterior herniotomy with en bloc laminoplasty, for patients with myelopathy and radiculomyelopathy caused by cervical disc herniation. METHODS: Here, the surgical outcomes and radiographic changes were retrospectively investigated. Thirty patients (13 patients with myelopathy, 13 patients with radiculomyelopathy, and 4 patients with C5 dissociated motor loss) who underwent this procedure were reviewed. The average age was 50 years (range 31-70 years), and the average follow-up period was 28 months (range 12-76 months). Neurologic improvements were evaluated using the Japanese Orthopaedic Association (JOA) Scoring System as well as radicular pain and deltoid muscle power. Postoperative axial symptoms were scored, and radiographic changes were noted. RESULTS: The mean JOA score improvement was 74.2% (range 27.3-100%). In all 13 patients, preoperative radicular pain completely resolved after surgery. Deltoid power (in cases of C5 dissociated motor loss) markedly increased postoperatively. Cervical lordosis significantly increased at the time of the last follow-up (P = 0.01). The postoperative axial symptom score significantly correlated with the numbers of opened laminae (P = 0.03). CONCLUSIONS: This technique was safe and effective. Radiographically, the range of motion in the cervical spine and at the affected disc levels was preserved. In the future, this surgical procedure can become an alternative method for cervical disc herniation treatment.     

A comparative study of surgical approaches for cervical compressive myelopathy

Since 1986, the authors have used anterior decompression and fusion to treat patients with one- or two-level lesions without spinal canal stenosis (Group A) and laminoplasty for patients with more than three-level lesions or spinal canal stenosis (Group P). The aim of this study was to compare surgical outcomes of anterior and posterior approaches for patients with cervical myelopathy because of spondylosis and disc herniation and to determine the cause of poor neurologic recovery after surgery. One hundred thirty-six patients were followed up for an average of 5.6 years. There were no significant differences in gender, preoperative neurologic deficits, axial symptoms, or duration of symptoms before surgery between the two groups. Mean recovery rates for disc herniations were 71.1% and 71.9% in Groups A and P, respectively. For spondylosis, mean recovery rates were 49.0% and 58.6% in Groups A and P, respectively. There were no differences in recovery rate for patients with either spinal disorder between Groups A and P. The neurologic recovery of patients with kyphotic spinal cord was inferior to that of patients with lordotic or straight spinal cord. It is possible that acquisition and maintenance of lordosis result in improvement of clinical outcomes after surgery for patients with myelopathy.     

The effect of cervical plating on single-level anterior cervical discectomy and fusion

The use of anterior plates for single-level cervical fusions is controversial. Previous studies that evaluated single and multiple-level fusions have shown increased and decreased fusion rates when cervical plates are used. The purpose of this study was to compare the clinical and radiographic success of single-level discectomy performed with and without anterior cervical plate fixation. During a 6-year period, 80 patients were surgically treated with a single-level anterior cervical discectomy. Forty-four patients had cervical plates, whereas 36 had fusions without plates (average follow-up, 2.3 years). The pseudarthrosis rates were 4.5% (2 of 44) for patients with plating and 8.3% (3 of 36) without plating. This difference was not significant (p = 0.653). There was no correlation of pseudarthrosis with sex, age, level of surgery, history of tobacco use, or the presence of previous anterior surgery. The amount of graft collapse for patients with plating was 0.75 mm compared with 1.5 mm for those without a plate (p = 0.026). The amount of kyphotic deformity of the fused segment was 1.2 degrees with plating compared with 1.9 degrees for patients without plating (p = 0.079). Ninety-one percent of the patients with plating had good or excellent results compared with 88% in the group without cervical plates, based on Odom's criteria. The addition of plate fixation for single-level anterior cervical discectomy and fusion is safe and not associated with a significant increase in complication rates. The pseudarthrosis rates are not significantly different when a cervical plate is used.     

Subsidence of stand-alone cervical cages in anterior interbody fusion: warning

Anterior cervical decompression and fusion with anterior plating of the cervical spine is a well-accepted treatment for cervical radiculopathy. Recently, to minimise the extent of surgery, anterior interbody fusion with cages has become more common. While there are numerous reports on the primary stabilising effects of the different cervical cages, little is known about the subsidence behaviour of such cages in vivo. We retrospectively reviewed eight patients with cervical radiculopathy operated upon with anterior discectomy and fusion with a stand-alone titanium cervical cage. During surgery, only the cartilage portion of the end plate was removed and the cages were filled with autologous cancellous bone graft from the iliac crest. To assess possible subsidence or migration, three different radiographic measurements in the sagittal plane were taken for each case, postoperatively and at the latest follow-up. Subsidence was defined as any change in at least one of our parameters of at least 3 mm. Follow-up time was 12–18 months (average 15 months). Five of the nine fused levels had radiological signs of cage subsidence. No posterior or anterior migration was observed. However, subsidence did not correlate with clinical symptoms in four of the five patients. The remaining patient with signs of subsidence, whose neck pain and neurologic symptoms had regressed in the early postoperative course, suffered recurrence of radiculopathy 6 months after the surgery. Her symptoms were explained by the subsidence of the cage and the subsequent foraminal stenosis observed on the magnetic resonance imaging (MRI) scan. At 15 months' follow-up, her cage was broken. Our preliminary results, so far limited in number, represent a serious warning to the proponents of stand-alone cervical cages     

Increased fusion rates with cervical plating for two-level anterior cervical discectomy and fusion

STUDY DESIGN: A retrospective review of all patients surgically treated with a two-level anterior cervical discectomy and fusion with and without anterior plate fixation by a single surgeon. OBJECTIVES: To compare the clinical and radiographic success of two-level discectomy and the effect of anterior cervical plate fixation. SUMMARY OF BACKGROUND DATA: Prior studies of multisegment fusions have shown decreased fusion rates correlating with the number of increased levels. The use of anterior plates for single-level cervical fusions is controversial. However, their use in multilevel fusions may be warranted because of the increased pseudarthrosis rates. METHODS: Over a 6-year period, 60 patients were treated surgically with a two-level anterior cervical discectomy and fusion by the senior author. Thirty-two patients had cervical plates, and 28 underwent fusions without plates. These patients were followed for an average of 2.7 years. Clinical and radiographic follow-up evaluations were performed. RESULTS: Of the 60 patients, 7 had a pseudarthrosis. The pseudarthrosis rates were 0% for patients with plating and 25% for those with no plating. This difference was statistically significant (P = 0.003). No correlation of pseudarthrosis with gender, age, level of surgery, history of tobacco use, or the presence of prior anterior surgery was found. There was significantly less graft collapse (P = 0.0001) in the patients without plates in whom pseudarthrosis developed (1.4 mm) than in those who had fusions with plates (0.3 mm). The amount of kyphotic deformity of the fused segment was 0.4 degree in patients with plating compared with 4.9 degrees in those without plating who developed a pseudarthrosis (P = 0.0001). CONCLUSIONS: The addition of plate fixation for two-level anterior cervical discectomy and fusion is a safe procedure with no significant increase in complication rates. The pseudarthrosis rates are significantly higher in patients treated without plate fixation. No nonunions occurred in the patients treated with plate fixation. There was significantly less disc space collapse and kyphotic deformity with the plated fusions than with the nonplated fusions, in which a pseudarthrosis developed. The complication rates for plated fusions are extremely low and do not differ from those for nonplated fusions.     

Anterior cervical fusion using porous hydroxyapatite ceramics for cervical disc herniation. a two-year follow-up.

BACKGROUND CONTEXT: The Smith-Robinson Method (SR), which employs autogenous bone, is the current standard for anterior cervical fusion (AF) surgery. However, autogenous bone has graft-related complications and morbidity, and harvesting it increases trauma and risk to the patient. The use of hydroxyapatite ceramic (HAP) inserts may provide a superior alternative. PURPOSE: To determine the efficacy of using HAP in AF. STUDY DESIGN/SETTING: A retrospective study of patients who had AF surgery with wide decompression and porous HAP inserts used to treat cervical disc herniation (CHD). PATIENT SAMPLE: We evaluated 36 patients who had single-level AF using HAP for CHD, without internal fixations, clinically and radiographically with a minimum follow-up of 2 years. There were 25 men and 11 women, with an average age of 49 years (age range, 24-78 years). Preoperative diagnosis included 25 cases with myelopathy and 11 cases with radiculopathy. OUTCOME MEASURES: We established four grades to classify the degree of bony fusion between the HAP and vertebra, based on any motion at the fused segment, any radiolucent zones (RZ) between vertebral bodies and the grafted HAP, and anterior or posterior bone formations on grafted HAPs. We evaluated the severity of myelopathy by applying the Japan Orthopaedic Association (JOA) scoring system. We evaluated the surgical outcome of the myelopathy patients using the Hirabayashi recovery rating, and for the radiculopathy patients, we used the Herkowitz criteria. METHODS: We retrospectively reviewed the radiographic and clinical records of all 36 patients from surgery up to periods ranging from 2 to 7 years after surgery, with the average period of follow-up being 4.5 years. We systematically classified the degree of bony fusion into four grades ranging from Grade 1 nonunion to Grade 4 complete union. RESULTS: None of the subjects showed Grades 1 and 2 fusion. Eleven percent of the cases showed Grade 3 and 89% showed Grade 4. Loss of height of the fused segment was observed in 29 cases with an average of 1.6 mm. A decrease of lordotic angle of the fused segment was observed in six cases with an average of 2.3 degrees. Four cases revealed cracked HAP inserts but achieved Grade 4 bone fusion. There was no evidence of collapse or displacement of HAPs. The results of the 11 radiculopathy patients were excellent in 10 cases and good in the remaining case. The recovery rate of the 25 myelopathy patients was 73.0%. CONCLUSIONS: Our method of anterior cervical fusion surgery using porous HAP inserted into resected end plates, combined with a wide decompression procedure, had clinical and radiographic results so satisfactory that we conclude that it can effectively replace the use of autogenous bone for treating cervical disc herniation.     

Outcome analyses of interbody titanium cage fusion used in the anterior discectomy for cervical degenerative disc disease

Anterior discectomy and fusion to treat cervical degenerative disc disease is the preferred procedure for many spine surgeons. The ideal device for structural reconstruction of the anterior cervical spine remains controversial. The purpose of this prospective study was to investigate the effectiveness of a non-threaded titanium cage in performing anterior spinal fusion for cervical degenerative disc disease. The clinical and radiologic data of 78 consecutive patients were reviewed. Neurologic outcome was assessed using Odom's criteria. Neck pain was graded using a 10-point visual analog scale. The cervical spinal curvature, the height of foramina, and fusion status were evaluated on preoperative and postoperative radiographs. Mean follow-up was 24.9 (range 18-35) months. An excellent or good result was found in 92% of the patients with radiculopathy, 69% of those with myelopathy, and 73% of those with myeloradiculopathy. Statistical analyses also showed improvement of cervical pain after surgery (P < 0.001) and a significant increase in foraminal height (P = 0.035). Cervical kyphosis was present in 27 (34%) patients before surgery; it was corrected to lordosis in 9. The fusion rate at 12 months and 24 months was 91% and 95%, respectively. No surgery or cage-related complication occurred in these patients. Non-threaded interbody cage fusion in this study achieved a high fusion rate and had a good neurologic outcome. These results suggest that non-threaded cage fusion is a safe and effective method for anterior cervical discectomy.     

颈椎前路钢板在下颈椎损伤的应用进展

对颈椎前路钢板在下颈椎损伤国外应用进展进行综述。颈椎前路钢板在设计上有限制性与非限制性两种类型,生物力学研究表明前者的固定强度明显优于后者,但易于在固定阶段对植骨块产生应力阻挡。手术指征主要为颈椎前柱损伤或颈椎后部骨与韧带复合体的损伤。但颈椎损伤存在高度不稳定时,前路钢板固定应联合颈椎后路稳定性手术。否则,术后须应用头环背心支具固定。对撑开屈曲型损伤,应警惕创伤性颈椎间盘突出,以免在牵引复位过程中发生严重的神经损伤。操作时应彻底解除脊髓前方压迫,植入三面皮质骨块,恢复前柱正常前凸,再行前路钢板固定。该方法的优点是达到了固定阶段即时稳定性,提高了植骨融合率,有利于康复。但加重了手术创伤,有发生与钢板或螺钉有关并发症的可能,晚期在临近融合区相邻椎间盘有退行性改变发生。因而在确定治疗方案时,要权衡利弊。     

前路三节段椎间盘切除减压治疗颈椎病的近期疗效分析

目的 分析颈前路三节段椎间盘切除减压术治疗颈椎病的临床与影像学结果.方法 2002年10月至2007年1月,对23例颈椎病患者行颈前路连续三节段椎间盘切除减压、自体髂骨植骨、钢板内固定术,男15例,女8例;年龄32～66岁,平均51.4岁.通过分析术前及随访时JOA评分,观察其改善率,并记录术后颈部症状及Odom分级.测量术前、术后1周及末次随访时颈椎侧位X线片,观察颈椎融合节段曲度(Cobb角).在末次随访时,观察融合节段的融合情况以及邻近节段退变情况.结果 随访时间11～48个月,平均19.8个月.20例脊髓型颈椎病患者术前JOA评分(11.1±1.0)分,术后3个月(14.6±1.0)分,两者比较差异有统计学意义,平均改善率62%.3例神经根型颈椎病患者末次随访时,2例症状全部消失,1例左侧三角肌肌力由术前2级恢复至4级.术后Odom分级:优15例,良4例,一般4例.术后17.4%(4/23)的患者颈部仍有症状.植骨融合率100%.术前Cobb角为3.7°,术后1周为10.8°,末次随访为10.4°.未观察到邻近节段病变.无神经系统及与内固定物相关的并发症.结论 颈前路三节段椎间盘切除减压、自体髂骨植骨融合、钢板内固定术可以获得很高的植骨融合率.     

Surgical treatment of cervical spondylotic myelopathy with anterior compression: a review of 67 cases

OBJECT: In patients with cervical spondylotic myelopathy (CSM), ventral disease and loss of cervical lordosis are considered to be relative indications for anterior surgery. However, anterior decompression and fusion operations may be associated with an increased risk of swallowing difficulty and an increased risk of nonunion when extensive decompression is performed. The authors reviewed cases involving patients with CSM treated via an anterior approach, paying special attention to neurological outcome, fusion rates, and complications. METHODS: Retrospectively, 67 cases involving consecutive patients with CSM requiring an anterior decompression were reviewed: 46 patients underwent anterior surgery only (1-to3-level anterior cervical discectomy and fusion [ACDF] or 1-level corpectomy), and 21 patients who required > 3-level ACDF or > or = 2-level corpectomy underwent anterior surgery supplemented by a posterior instrumented fusion procedure. RESULTS: Postoperative improvement in Nurick grade was seen in 43 (93%) of 46 patients undergoing anterior decompression and fusion alone (p < 0.001) and in 17 (81%) of 21 patients undergoing anterior decompression and fusion with supplemental posterior fusion (p = 0.0015). The overall complication rate for this series was 25.4%. Interestingly, the overall complication rate was similar for both the lone anterior surgery and combined anterior-posterior groups, but the incidence of adjacent-segment disease was greater in the lone anterior surgery group. CONCLUSIONS: Significant improvement in Nurick grade can be achieved in patients who undergo anterior surgery for cervical myelopathy for primarily ventral disease or loss of cervical lordosis. In selected high-risk patients who undergo multilevel ventral decompression, supplemental posterior fixation and arthrodesis allows for low rates of construct failure with acceptable added morbidity.     

陈旧颈椎骨折的前路手术治疗

目的 探讨陈旧颈椎骨折脱位的前路手术治疗的效果。方法 对我院1995～1999年间行前路手术治疗的42例陈旧颈椎骨折脱位患者均行植骨融合和钢板内固定。其中22例单间隙融合，20例椎体次全切除；其中12例行自体髂骨植骨，30例行CHA植骨。所有患者术前均行颈椎X线片、CT及MRI了解骨折脱位情况，术后摄颈椎X线片了解植骨融合状况，颈椎曲线恢复保持情况和内固定稳定性。对所有患者进行JOA评分并计算其改善率。结果 所有患者随访3.5～7.2年(平均4.2年)，术后功能的JOA评分均有改善，无术后症状恶化、全身和局部并发症发生。固定椎保持稳定，颈椎曲线得以保持，无明显植骨不愈合表现。1例双节段植骨患者头侧螺钉断裂，但植骨已融合。余者内固定均稳定。结论 前路手术对治疗陈旧颈椎骨折脱位有较好的效果。严格掌握适应证，充分恢复伤椎高度及曲线，牢固的内固定是手术治疗成功的关键。     

多节段脊髓型颈椎病的外科治疗

目的 探讨多节段脊髓型颈椎病的外科治疗入路及方法。方法 自2009-01-2013-01行连续性多节段脊髓型颈椎病手术治疗63例患者,其中36例行前路分节段脊髓减压,27例行后路改良锚定单开门椎板扩大成形术。结果 所有患者得到随访平均24个月（12-36个月）。前路组平均手术时间明显长于后路组,前路组术中失血量多于后路组（P〈0.05）,而住院天数后路组长于前路组,前路组术后后凸畸形矫正方面明显好于后路组,在末次随访VAS评分2组比较差异无统计学意义（P〉0.05）。在术后末次随访时VAS评分、JOA评分、Odom评分、NDI评分等2组无明显区别,在轴性症状、C5神经根麻痹方面后路组多于前路组。结论 前路组及后路组在治疗多节段脊髓型颈椎病均可以取得满意的临床疗效,前路组在手术时间、出血量多于后路组,前路组恢复颈椎的序列,并发症少于后路组,但必须根据患者具体情况选择手术方式。     

A comparison of anterior cervical fusion, cervical laminectomy, and cervical laminoplasty for the surgical management of multiple level spondylotic radiculopathy

The risks and success of surgery for multiple level cervical spondylotic radiculopathy differs from that of single level disease. The problems associated with multiple level anterior fusion over single level fusion include higher pseudoarthrosis rates than that associated with single level disease. Bilateral and multiple level laminectomy carries the risk of potential instability. Cervical laminoplasty, until recently, has only been performed for myelopathy secondary to ossification of the posterior longitudinal ligament (OPLL) or cervical stenosis. The purpose of this report is to compare the results and complications of 45 patients with a least a 2-year follow-up who had undergone anterior fusion, cervical laminectomy, or cervical laminoplasty for the surgical management of multiple level cervical radiculopathy due to cervical spondylosis. 18 patients (58 levels) underwent anterior fusion, 12 patients (38 levels) had a cervical laminectomy, and 15 patients (57 levels) underwent a cervical laminoplasty. Roentgenograms indicated spinal stenosis (sagittal diameter less than 12 mm) at 28 levels (15 patients) for the anterior fusion group, 14 levels (9 patients) in the laminectomy group, and 24 levels (13 patients) in the laminoplasty group. Subluxation (2 mm or less) was present at 14 levels (13 patients) in the anterior fusion group, nine levels (9 patients) in the laminectomy group, and 15 levels (8 patients) in the laminoplasty group. Loss of lordosis was present in eight patients undergoing anterior fusion, six patients undergoing laminectomy, and six patients who had a laminoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)     

颈椎前路融合术后发生症状性邻近节段退变的临床研究

目的:探讨分析与颈椎前路融合术后发生症状性邻近节段退变相关的因素。方法:自2001年3月-2006年7月共收治354例颈椎病患者,获得随访的263例,其中男185例,女78例,手术时年龄35~76岁,平均51岁,其中神经根型颈椎病54例,脊髓型颈椎病183例,合并两者的有26例。所有患者均接受前路减压、自体髂骨植骨、前路钢板内固定。根据门诊随访,综合评估所有患者的术后临床表现、神经系统及术前术后影像学表现,评价对象包括年龄,性别,融合椎体数,术前颈椎的曲度、活动度,椎管的前后径以及邻近节段的椎间盘突出和椎体前缘骨赘形成等,并根据随访时的侧位X线片将头尾两端邻近椎间隙的骨赘形成程度分为4级,统计学分析引起症状性邻近节段退变的相关因素以及邻近节段退变与骨赘形成程度的关系。结果:263例患者中有39例(14.8%)出现了症状性邻近节段病变,其中男23例,女16例,手术时年龄42~65岁,平均55岁,从手术后到出现邻近节段病变的时间为4~11年,出现邻近节段病变的平均年龄为61岁。这些症状表现为原有颈椎病症状部分或完全缓解后再次出现与邻近节段椎间盘突出相对应的神经症状与体征,而在原手术节段没有脊髓受压的表现。术前脊髓MRI上邻近节段硬膜有压迹或融合节段头侧邻近节段椎间盘低信号的患者,术后发生症状性邻近节段退变的概率明显高于未出现症状的患者,而年龄,性别,融合椎体数,术前颈椎的曲度,活动度,椎管的前后径等研究对象与症状性邻近节段退变没有明显的相关性(P>0.05)。对于发生症状性邻近节段退变的患者,有26例(67%)钢板头端邻近节段发生了骨化,与尾端骨化相比,P<0.01,骨化程度随临床症状的加重而加重。结论:对于因颈椎病而行颈椎前路融合钢板内固定的患者,术前脊髓MRI示有邻近节段硬膜有压迹或融合节段头侧邻近节段椎间盘退变表现者,术后容易发生症状性邻近节段退变,这种退变在侧位X线上可表现钢板头端邻近椎间隙骨化。     

Maintaining lumbar lordosis with anterior single solid-rod instrumentation in thoracolumbar and lumbar adolescent idiopathic scoliosis.

STUDY DESIGN: A prospective radiographic evaluation of 20 consecutive patients with primary lumbar or thoracolumbar adolescent idiopathic scoliosis who were treated with anterior convex compressive single solid-rod spinal instrumentation and structural titanium mesh (Harms) cages. OBJECTIVES: To evaluate a lordosis-preserving anterior single solid-rod instrumented fusion technique for these specific adolescent idiopathic curves. SUMMARY OF BACKGROUND DATA: Maintaining instrumented segmental lumbar lordosis after anterior fusion and instrumentation for thoracolumbar and lumbar curves has been difficult. Twenty consecutive patients who underwent anterior single solid-rod fusion, aged 18 or younger with a primary thoracolumbar or lumbar curve, were observed for preservation of lordosis for a minimum of 2 years. METHODS: All patients underwent an identical anterior surgical technique, involving discectomies and anulectomies of all convex discs, structural titanium mesh (Harms) cages placed in the anterior half of all disc spaces below T12, morselized rib autograft packed in all disc spaces to be fused and inside the cages, and anterior single solid-rod (5.0-mm or 5.5-mm diameter) convex compressive spinal instrumentation with appropriate lordotic rod contour and rod rotation as necessary. The anterior rod was placed just posterior to the cages to optimize lordotic contouring of the spine during compression. None of the patients was braced after surgery. The lowest instrumented vertebrae (LIV) were L2 (n = 3), L3 (n = 15), and L4 (n = 2), typically the lower end vertebra of the Cobb measurement. RESULTS: Measurements for the primary coronal Cobb before surgery, 1 week after surgery, and 2 years after surgery were 48 degrees, 11 degrees, and 12 degrees; for C7 plumb line deviation from the midline: 3.6 cm, 1.9 cm, and 1.2 cm; for lowest instrumented vertebra translation: 31 mm, 15 mm, and 15 mm; and for LIV tilt: 29 degrees, 6 degrees and 6 degrees, respectively. Sagittal measurements before surgery, 1 week after surgery, and 2 years after surgery were: T12-L2: -1 degree, -6 degrees, and -6 degrees; T12-LIV: -8 degrees, -13 degrees, -9 degrees; T12-S1: -61 degrees, -56 degrees, -60 degrees; and entire instrumented levels: -6 degrees, -9 degrees, and -6 degrees, respectively. Coronal plane correction improved: 75% in the primary Cobb, 66% in the plumb line, 50% in LIV translation, and 80% in LIV tilt. Sagittal plane alignment improved in T12-L2 lordosis (P < 0.01) with preservation of physiologic lordosis in the instrumented levels, T12-LIV, and T12-sacrum. There were no instrumentation failures, pseudarthroses, or reoperations. CONCLUSIONS: Coronal plane correction with preservation of thoracolumbar and lumbar lordosis 2 years after anterior convex compressive spinal instrumentation was accomplished using a lordotically contoured single solid rod with structural cages placed anteriorly in the disc spaces of patients with primary thoracolumbar or lumbar adolescent idiopathic scoliosis.     

人工椎间盘置换术治疗跳跃型多节段颈椎病的中期疗效

 目的 评价 Bryan 人工间盘置换术治疗跳跃型多节段颈椎病的疗效。方法 回顾性分析 2002 年 2 月至 2012 年 5 月接受 Bryan 间盘置换术（Bryan 组）或颈前路减压植骨融合术（ACDF 组）治疗的跳跃型多节段颈椎病患者相关资料。临床功能评估采用日本矫形外科协会（Japanese orthopaedic association,JOA）评分、颈椎功能障碍指数（neck disability index,NDI）、疼痛视觉模拟评分（visual analoguc scale,VAS）,影像学评估采用颈椎矢状位曲度、颈椎整体活动度及中间节段活动度,并于末次随访时评估邻近节段退变情况。结果 49 例患者随访超过 24 个月,Bryan 组 18 例,ACDF 组 31 例。两组患者性别、年龄、疾病类型等人口学资料的差异无统计学意义。两组患者术后 JOA、NDI、VAS 评分均较术前有明显改善。两组间各时间节点比较仅末次随访时 VAS 评分的差异有统计学意义。Bryan 组术后轴性症状发生率、颈椎活动度和未手术节段活动度分别为 11.1%、35.5°±5.9°和 7.3°±1.4°,ACDF 组分别为 45.2%、24.5°±6.2°、10.1°±1.6°,差异均有统计学意义。Bryan 组患者邻近节段无明显退变,ACDF 组 2 例出现退变,但无需再次手术。结论 应用 Bryan 间盘置换术治疗跳跃型多节段颈椎病,可有效改善神经功能,保留颈椎整体活动度,减少未手术节段活动度的代偿性增加,从而降低邻近节段退变及轴性症状发生率。     

Kyphotic malalignment after anterior cervical fusion is one of the factors promoting the degenerative process in adjacent intervertebral levels

The aim of this study was to determine whether postoperative malalignment of the cervical spine after anterior interbody fusion surgery promotes degenerative changes in the neighboring intervertebral discs. Forty-two patients who underwent anterior interbody fusion surgery for cervical spondylosis and disc herniation (34 men, 8 women) were followed for an average of 9.8 years. The average age at surgery was 50.2 years. Twenty-three patients underwent a single-level fusion, 17 underwent two-level fusion, and 2 had three levels fused. The Japanese Orthopaedic Association cervical myelopathy score, with a normal score 17 points, was 11.7 before surgery and 14.9 at follow-up. Neurological status was significantly improved postoperatively, and the improvement was preserved thereafter in most cases (paired t-test, P<0.001). Degenerative changes were evident on radiological examination in the levels adjacent to the fused segment in 21 of the 42 (50%) patients. Eight of these 21 patients demonstrated neurological deterioration caused by an adjacent disc lesion. A total of 43% of the patients with adjacent-level degeneration had malalignment of the cervical spine, such as kyphosis or sigmoid curvature. In addition, degenerative change in adjacent intervertebral levels was observed in 77% of kyphoses of the fused segment. These were statistically significant (Fisher exact method, P<0.05, P<0.04, respectively). Our findings suggest that one of the factors promoting degenerative change in adjacent intervertebral levels after anterior cervical fusion for degenerative disorders is postoperative kyphotic change in the cervical spine and the fused segment.     

Treatment of multilevel cervical fusion with cages

BACKGROUND: Multilevel cervical discectomy usually requires plate and screw fixation for maintaining the spinal curvature, and increasing the graft fusion rate. However, the use of plate and screw fixation may cause a few complications, such as screw breakage, screw pullout, esophagus perforation, and cord or nerve root injury. In this study, we try to use cages to replace plate function in multilevel cervical fusion. METHODS: From January 1997 to June 2001, there were 180 consecutive cases of multilevel cervical degenerative disease. We randomized them into three groups: Group A (60 patients) underwent anterior discectomy and polyetheretherketone (PEEK) fusion, Group B (50 patients) underwent anterior discectomy, autogenous iliac crest graft (AICG) fusion and plate fixation, and Group C (70 patients) underwent anterior discectomy and AICG only. X-ray of cervical spine was taken every 3 months until fusion was complete. Spinal curvature was measured by lateral view of X-ray. The functional and working status were evaluated by Prolo scale. Blood loss and operation time were recorded, respectively. RESULTS: The total complication rates were 3.3%, 16%, and 54.3% in Groups A, B, and C respectively. The graft complications were evaluated by radiographic findings (graft collapse, nonunion, or dislodged graft). However, only 37.1% of patients (13/35) with graft complications had clinical symptoms (severe neck pain, radicular pain, or neurologic deficits). The fusion rate was better, and the time to fusion was sooner in Groups A and B than Group C, p < 0.001 (chi(2) test). PEEK cage is statistically better than plating group in total complications, p < 0.05. Graft collapse and nonunion were the major graft complications in Group C (AICG without plating). Screw pullout, and screw breakage were the main causes of plating complication. Blood loss was minimum in Group A, p < 0.05. Spinal lordosis increased by a mean of 4.61 +/- 2.93 mm and 1.68 +/- 5.02 mm in Groups A and B, respectively, but spinal kyphosis increased by a mean of -2.09 +/- 4.77 mm in Group C. Group A had a statistically better Prolo scale than Group C, p < 0.0001. CONCLUSIONS: Both PEEK cage without plating and AICG with plating are good methods for interbody fusion in multilevel cervical degenerative diseases. They increase spinal lordosis and graft fusion rate, and cause fewer surgical complications. However, PEEK cage is preferred in our study for multilevel fusion, because it has the fewest complication rates and the least amount of blood loss.     

Outcome of single level anterior cervical discectomy and fusion using nano-hydroxyapatite/polyamide-66 cage

Background:

Cages have been widely used for the anterior reconstruction and fusion of cervical spine. Nonmetal cages have become popular due to prominent stress shielding and high rate of subsidence of metallic cages. This study aims to assess fusion with n-HA/PA66 cage following one level anterior cervical discectomy.

Materials and Methods:

Forty seven consecutive patients with radiculopathy or myelopathy underwent single level ACDF using n-HA/PA66 cage. We measured the segmental lordosis and intervertebral disc height on preoperative radiographs and then calculated the loss of segmental lordosis correction and cage subsidence over followup. Fusion status was evaluated on CT scans. Odom criteria, Japanese Orthopedic Association (JOA) and Visual Analog Pain Scales (VAS) scores were used to assess the clinical results. Statistically quantitative data were analyzed while Categorical data by χ² test.

Results:

Mean correction of segmental lordosis from surgery was 6.9 ± 3.0° with a mean loss of correction of 1.7 ± 1.9°. Mean cage subsidence was 1.2 ± 0.6 mm and the rate of cage subsidence (>2 mm) was 2%. The rate of fusion success was 100%. No significant difference was found on clinical or radiographic outcomes between the patients (n=27) who were fused by n-HA/PA66 cage with pure local bone and the ones (n=20) with hybrid bone (local bone associating with bone from iliac crest).

Conclusions:

The n-HA/PA66 cage is a satisfactory reconstructing implant after anterior cervical discectomy, which can effectively promote bone graft fusion and prevent cage subsidence.