A refined method of en bloc open-door laminoplasty for resection of intradural spinal tumors in the thoracic and lumbar spine

BackgroundThe open-door laminoplasty has been used to treat cervical spondylotic myelopathy. This technique has been applied to the surgical treatment of thoracic and lumbar spinal canal tumors instead of simple laminectomy or hemilaminectomy. However, previously reported laminoplasty methods did not keep posterior supporting elements intact such as the laminae and the spinous processes with supraspinous and interspinous ligaments, and almost all of them needed instruments for the fixation of reconstructed laminae. The purpose of this paper is to introduce our open-door laminoplasty method, which keep all posterior supporting elements intact and reconstruct the laminae without instrument.MethodsEight patients (mean age 61 years) underwent en bloc open-door laminoplasty in the thoracic and lumbar spine for resection of intradural spinal tumors. Two grooves are made bilaterally on the laminae just medial side of the facet joints. One-half of each spinous process of the adjacent vertebrae above and below the laminoplasty is cracked diagonally to create a green stick fracture and bent to the hinged side for sufficient elevation of the laminar flap. After tumor resection, the laminar flap is restored to its original site, resulting in the complete preservation of the posterior supporting elements.ResultsOperative exposure was good and permitted complete resection. No complications such as postoperative spinal canal stenosis or kyphosis were observed. Computed tomography(CT) indicated that bony fusion occurred in all cases.ConclusionThe supraspinous and interspinous ligaments above and below laminoplasty were kept intact during surgery in our method. Therefore, the continuity of posterior supporting elements (laminae and spinous processes connected by supraspinous and interspinous ligaments) were completely preserved.     

Intradiscal pressure and kinematic behavior of lumbar spine after bilateral laminotomy and laminectomy.

BACKGROUND CONTEXT: Bilateral laminotomy has been proposed as an alternative to laminectomy for decompression of lumbar spinal stenosis. Preservation of the posterior midline ligaments with laminotomy is presumed to maintain spinal segment stability. There have been no previous studies that directly compare the amount of destabilization and increase in disc pressures between the two procedures. PURPOSE: To quantify spinal segmental instability caused by bilateral laminotomy and laminectomy, and to compare the central and peripheral intradiscal pressures after the two procedures. STUDY DESIGN/SETTING: Mechanical testing of the lumbar motion segments of calf spines. METHODS: Nine fresh calf spines were tested under flexion, extension, lateral bending and axial rotation, intact first, then after laminotomy and laminectomy at the level of L4-L5. Four miniature pressure transducers were implanted in the central and peripheral disc at L4-L5 to measure intradiscal pressures. Three-dimensional motion was measured with motion analysis system. RESULTS: Comparing with bilateral laminotomy, laminectomy showed significant increase in segmental motion at the surgical level in flexion (16%, p<.05), extension (14%, p<.04) and right axial rotation (23%, p<.03). In flexion, the stress at the anterior annulus increased a nonsignificant 20% after laminotomy, but significant 130% after laminectomy (p<.02). In the intact spine, the posterolateral annulus experienced the highest stress with lateral bending to the same side when compared with other loading directions. This stress remained unchanged after laminotomy but increased 9% after laminectomy (p<.06). In rotation, axial intradiscal stresses were evenly distributed and unchanged after each procedure. CONCLUSIONS: Laminectomy causes more destabilization of a spinal motion segment than laminotomy and significantly increases disc stress in the anterior annulus.     

棘突截骨椎管成形术治疗退行性腰椎疾病

目的采用棘突截骨椎管成形术治疗退行性腰椎疾病,术后进行临床与影像学评估。方法术式为后正中切口,显露一侧椎板后在棘突基底部截骨,并将棘突-韧带-骶棘肌推离对侧椎板,完成全椎板显露。切除椎板上、下缘和黄韧带,并潜式扩大中央椎管和神经根管或摘除椎间盘。应用此术式治疗退行性腰椎管狭窄症、腰椎间盘突出合并发育性腰椎管狭窄症、腰椎间盘中央型突出钙化、腰椎黄韧带骨化患者共37例。其中单节段减压24例,两节段减压13例。术后进行Oswestry疗效评分与影像学观察。结果术后1年随访34例,疗效优良率为82.4%;术后3年随访27例,疗效优良率为81.5%。术后CT显示椎管直径明显增加,棘突截骨愈合率为87%。结论棘突截骨椎管成形术操作简单,手术并发症少,对腰椎后柱张力带结构破坏小,主椎管和侧椎管减压充分,是治疗退行性腰椎疾病疗效较为满意的一种术式。     

Biomechanical evaluation of lumbar spinal stability after graded facetectomies

In an in vitro experiment using fresh human lumbar functional spinal units, the effects of the division of the posterior ligaments (consisting of the supraspinous/interspinous ligaments) and graded facetectomies were investigated. The graded facetectomies consisted of unilateral and bilateral medial facetectomies, and unilateral and bilateral total facetectomies. Six kinds of moments were applied and ranges of motion (ROM) and neutral zones (NZ) were determined three-dimensionally by stereophotogrammetric methods. Range of motion was not affected by the division of the supraspinous/interspinous ligaments for all load modes. In flexion, ROM increased slightly after unilateral medial facetectomy. In right axial rotation, ROM increased after left unilateral total facetectomy. Range of motion was not affected, even by bilateral total facetectomies, in extension and lateral bendings. This study suggested that medial facetectomy does not affect lumbar spinal stability, and conversely, total facetectomy, even created unilaterally, makes the lumbar spine unstable.     

Effects of aging and spinal degeneration on mechanical properties of lumbar supraspinous and interspinous ligaments.

BACKGROUND CONTEXT: The effects of aging and spinal degeneration on the mechanical properties of spinal ligaments are still unknown, although there have been several studies demonstrating those of normal spinal ligaments. PURPOSE: To investigate the mechanical properties of the human posterior spinal ligaments in human lumbar spine, and their relation to age and spinal degeneration parameters. STUDY DESIGN/SETTING: Destructive uniaxial tensile tests were performed on the human supraspinous and interspinous ligaments at L4-5 level. Their mechanical properties were compared with age and spinal degeneration using several imaging modalities. PATIENT SAMPLE: Twenty-four patients with lumbar degenerative diseases on whom posterior surgeries were performed, with the age ranging from 18 to 85 years. OUTCOME MEASURES: The ultimate load and elastic stiffness as structural properties, the degree of disc degeneration, range of segmental motion, the disc height, disc space narrowing ratio and degree of facet degeneration as the parameters of spinal degeneration. METHODS: Twenty-four supraspinous and interspinous ligaments at the L4-5 level were obtained from posterior surgeries of patients with lumbar degenerative disease. The mechanical tests of bone-ligament-bone complexes were performed in a uniaxial tensile fashion with a specially designed clamp device. The ultimate load and elastic stiffness were calculated as structural properties. The degree of disc degeneration, range of segmental motion, the disc height, disc space narrowing ratio and degree of facet degeneration were examined by using radiographs, computed tomography and magnetic resonance imaging. RESULTS: The average and SD value of ultimate load, elastic stiffness, tensile strength and elastic modulus were 203+/-102.9 N, 60.6+/-36.7 N/mm, 1.2+/-0.6 Mpa and 3.3+/-2.1 Mpa, respectively. A significant negative correlation was found between age and tensile strength (p= 0.02). The specimens with facet degeneration showed lower values in tensile strength and elastic modulus than those without facet degeneration (p<0.04). However, no correlation was found between disc-related parameters and tensile strength. CONCLUSIONS: The mechanical strength of human lumbar posterior spinal ligaments decreases with age and facet degeneration, particularly in the ligament substance.     

Clinical study of lumbar spinal canal stenosis on 70 operated cases --clinical symptoms, pathogenesis, operative method, postoperative results

In surgical treatment of lumbar spinal canal stenosis, the stenotic area related to the clinical symptoms was determined and the stenotic form and stenotic factors in this stenotic area were estimated before operation. The most appropriate decompression of the stenotic area was performed taking the stenotic form into consideration and retaining the spinous process and interspinous ligament. In cases of stenosis of the spinal canal, posterolateral decompression of the dural sheath was performed by means of resection of the medial edge of the bilateral inferior articular processes and the yellow ligaments. In cases of stenosis of the spinal canal associated with stenosis of the lateral recess, the root was decompressed by unroofing the lateral recess in addition to posterolateral decompression of the dural sheath. And in cases with stenosis of the lateral recess, the root in an affected area was decompressed. Neither operation on the intervertebral disc nor incision of the dural sheath was performed. After operation as described above, symptoms, operative findings and postoperative results were investigated in 70 cases which could be directly examined. In this paper we discuss the relationship between the symptoms and the stenotic area, stenotic forms and stenotic factors. When our postoperative results were compared with those of cases with extensive laminectomy, it was seen that none of the patients we treated had low back pain nor recurrence of intermittent claudication and that lessening of paralysis was sufficient.     

A biomechanical evaluation of an interspinous device (Coflex) used to stabilize the lumbar spine

A biomechanical study of an interspinous stabilization spinal implant (Coflex) was carried out using eight human lumbar L4/L5 motion segments. Each motion segment was tested in compression, then flexion/extension, then lateral bending, and then axial rotation at five conditions: 1) intact; 2) partial destabilization (by cutting the supraspinous and interspinous ligaments, the ligamentum flavum, the facet capsules, and 50% of the inferior bony facet bilaterally); 3) stabilization with the Coflex device; 4) complete destabilization with total laminectomy; and 5) stabilization with pedicle screws and rods. The most important result is that the motion segment after destabilization and insertion of the Coflex device does not allow significantly more or less motion than the intact specimen in either flexion/extension or axial rotation. Thus the Coflex offers nonrigid fixation and can return a partially destabilized specimen back to the intact condition in terms of motion in flexion/extension and axial rotation.     

Biomechanical study of adjacent intervertebral motion after lumbar spinal fusion and flexible stabilization using polyethylene-terephthalate bands

Thirty fresh-frozen calf cadaveric spinal specimens (L3-L6) were used to investigate the effect of flexible stabilization and fixation on the adjacent intervertebral motion segment. The intact spine that had not been subjected to injury was used for comparison as control. The destabilized spine was made up of specimens from which the bilateral facet joints and the supraspinous and interspinous ligaments were removed. The flexible stabilized spine was applied with pedicle screws and polyethylene-terephthalate bands, and the fixed spine was applied with pedicle screws and rods at the L4-L5 segment. The range of motion (ROM) was measured under flexion, extension, and bilateral bending moments, and the ROM ratio (ROM of each model versus ROM of the comparison model) was calculated at L3-L4, L4-L5, and L5-L6 segments. In the flexible stabilized spine, the restriction of motion was high under flexion and bilateral bending moments, and the mobility of the adjacent intervertebral motion segments approximated the normal lumbar vertebra. In the fixed spine, the ROM ratio increased at the cranial and caudal adjacent segments.     

Endoscopic decompression combined with interspinous process implant fusion for lumbar spinal stenosis

Objective： To propose a new technique to treat lumbar spinal stenosis with median approach endoscopic decompression combined with interspinous process implant fusion and evaluate the initial clinical outcome.
Methods： This study involved 30 patients who had neurogenic commitment claudication over 2 years and were resistant to conservative therapy. All cases were treated using the median approach endoscopic decompression combined with interspinous process implant fusion in 2006. Clinical signs and radicular pain were noted and evaluated preoperatively and at the 1st month and 3rd month postoperatively. Japanese Orthopedic Association （JOA） score was used to evaluate leg and back pain. X-ray films at flexion and extension were applied to evaluate the range of motion at involved segments. Results： There was a significant increase in JOA score postoperatively, but no significant difference preoperatively or postoperatively between the two groups.The range of motion at involved segments was significantly higher in the control group.
Conclusions： The median approach endoscopic decompression is an ideal method for bilateral radiculopathy resulting from lumbar spinal canal stenosis. The combination with interspinous process implant fusion can stabilize the spine. The initial clinical outcome is exllent. Preservation of adjacent level disease can be assessed only in long-term follow-up.     

Biomechanical evaluation and comparison of polyetheretherketone rod system to traditional titanium rod fixation on adjacent levels

PurposeAdjacent segment degeneration or fracture of the vertebral body was commonly reported in rigid fusion. Use of semirigid instruments such as PEEK rod system could be an alternative treatment. However, the biomechanical implications of using PEEK rod systems are not well understood. Purpose of this study was to compare a PEEK rod fixation system to traditional titanium rod fixation via a finite element analysis.MethodsA lumbar spine model from L2–L5 vertebral bodies was constructed. A fusion model, created by modifying the intact lumbar model, was used to simulate anterior interbody and posterolateral lumbar fusion. Loading was applied through flexion, extension, lateral bending, torsion.ResultsThe greatest increase in stress was estimated at the upper disc adjacent to the titanium rod with interbody fusion. The lower increase in stress on adjacent segments occurred with PEEK rod fixation without fusion and noninstrumented posterolateral lumbar fusion models. With the same fusion or nonfusion procedures, the stress on discs and facet joints of adjacent segments in the PEEK rod group decreased by 5–25% of that in the titanium rod group for all loading conditions.ConclusionIn comparison with rigid fixation, some potential advantages of using PEEK rod systems include a reduced stress on adjacent segment disc and facet joint, and the elastic ability of PEEK rod fixation allows for a greater range of motion, which may reduce the incidence of clinical complications seen with rigid fusion devices.     

Biomechanical effect of graded minimal-invasive decompression procedures on lumbar spinal stability

Introduction

Decompression surgery represents the standard operative treatment for lumbar spinal stenosis, but this procedure is often combined with fusion surgery. It is still discussed whether minimal-invasive decompression procedures are sufficient and if they compromise spinal stability as well. The aim of this study was to analyze the effects of different minimal-invasive decompression procedures on the range of motion (ROM) of the decompressed and adjacent segments under preload conditions.

Methods

Fourteen fresh frozen human cadaver lumbar spines (L2–L5) were tested in a spinal testing device with a moment of 7.5?N?m in flexion/extension, lateral bending and rotation with and without a preload. The ROM of the decompressed segment L3/4 and the adjacent segments L2/L3 and L4/L5 was measured intact and after creating a gradual defect with resection of the interspinous ligament (ISL), bilateral undercutting decompression, detachment of the supraspinous ligament (SSL) and bilateral medial facetectomy.

Results

The resection of the ISL had no significant effect on the ROM of all segments. Undercutting decompression showed a significant increase in the ROM of all segments during flexion/extension and lateral bending. The detachment of the SSL caused a significant increase of ROM during flexion/extension in the instrumented and adjacent segments. After bilateral medial facetectomy, a decrease of ROM was observed in all directions of motion except flexion/extension with preload.

Conclusions

The results support minimal-invasive procedures for the preservation of spinal stability. Therefore, surgeons can determine which grade of decompression procedure can be performed in the individual patient without requiring additional fusion to maintain spinal stability.     

Lumbar diskectomy without or with spondylodesis? Revival of an old dilemma

Indications for spine fusion in combination with removal of a lumbar intervertebral disc are not as well defined or as widely accepted. Extreme opinions have been expressed on both side of this issue, but it seems unreasonable that every segment should be fused after removal of a disc or that none should be. The indication for fusion or for no fusion is often based on the specialist to whom the patient is referred. Orthopedists perform often fusion, neurosurgeons rarely. The problem is not the superiority of combined operation or simple disc excision, but the right indication for one or other procedure. It is clear that for the patient with acute disc displacement with leg-pain as the predominant symptom, simple laminectomy and disc excision will yield good results in most cases. Basically the are two indications for combined operation: the first of this is a strong history of instability troubles prior to the disc prolapse; second indication is the bilateral hemilaminectomy and discectomy, which can lead the spine quite instable. Indication for secondary spinal fusion are: 1) the presence after disc excision of complain of pain in the back with relatively little sciatic radiation, sometimes as intermittent claudication; 2) the overproduction of scar tissue is seen very often in instable segment after disc excision and partial or complete facetectomy. Decompression of the nerve root and fusion may result in a great benefit. Finally we recall the possibility to perform simple fusion in flexion without excision of the disc and without laminectomy in cases with median protrusion of the disc, seen in CT in patients with chronic low back pain and inconstant radicular pain radiation. We describe our own technic of combined operation.     

下腰椎不同融合方式的有限元研究

目的 建立正常人L3～5节段有限元模型，研究腰椎椎体间、后外侧以及环形融合方式下融合节段的稳定性，融合相邻节段椎间盘应力的变化。方法选择一名32岁正常男性，采用CT扫描，借助CATIAV5和Marc／MSC．Mentat软件，建立正常人L3～5三维非线性有限元模型。通过模拟手术失稳及在此基础上的椎体间、后外侧及环形融合，建立相应的4种有限元模型。各模型施加载荷，观察其应力分布、融合节段的角位移变化及邻近节段椎间盘的最大有效应力。结果环形融合的稳定性优于椎体间融合与横突间融合，其中以前屈与后伸加载时尤为明显。除前屈外，椎体间融合的稳定性总体优于单纯横突间融合。融合邻近节段椎间盘的最大有效应力均出现于前屈时，然后依次为侧弯、扭转、后伸。椎体间融合时邻近椎间盘的最大有效应力增加最小，横突间融合次之，环形融合时最大。结论下腰椎后路减压后行融合术时，环形融合的稳定性最好，椎体间融合的稳定性优于横突间融合。椎体间融合引起邻近节段退变的可能性最小，环形融合可能性最大，而横突间融合介于二者之间。     

Postoperative, appositional ossifications after lumbar laminectomy

QUESTION: Post-laminectomy segmental hypermobility as well as appositional ossification were suggested by many authors to contribute to the unsatisfactory long-term results of laminectomy. The aim of this study was to find out whether segmental instability, among other factors, influences the degree of appositional ossification following laminectomy. METHODS: 55 out of 72 patients operated upon by laminectomy or hemilaminectomy for degenerative lumbar spinal stenosis were examined by radiography after an average follow-up period of 5.2 years. Appositional ossification at the site of surgery was evaluated in relation to lumbar instability, the number of segments undergoing laminectomy, and whether simultaneous fusion was done. Instability was determined by measuring angulation and translation using lateral flexion and extension views of the lumbar spine, whereas new-bone formation was best evaluated on antero-posterior radiographs. RESULTS: 94% of the patients had appositional ossification at the site of laminectomy. Patients undergoing simultaneous fusion with laminectomy had a significantly lower amount of appositional ossification compared to patients undergoing laminectomy without segmental fusion. Radiographically measured segmental instability, the number of segments undergoing laminectomy, age, and sex of the patients did not influence the extent of ossification. CONCLUSIONS: Postoperative appositional ossification at the posterior site of resection are seen regularly following laminectomy. The extent of appositional ossification does correlate with lumbar fusions, but does not correlate with the extent of radiographically measured lumbar instability, the number of segments undergoing laminectomy, or the age and sex of the patients. CLINICAL RELEVANCE: Simultaneous lumbar fusion with laminectomy is proved to be associated with less appositional ossification. Therefore lumbar fusion should be considered when planning surgery for spinal stenosis.     

Some new observations on the functional anatomy of the lower cervical spine.

The ligaments are a major stabilizing component of the cervical spine and are critical for spinal stability as well as stabilization therapy. Relatively little information is available on the anatomic details and function of the cervical ligaments. Fifteen fresh cervical spines were dissected and the ligaments examined grossly and functionally. Eight different intrinsic ligaments of the lower cervical spine were identified. The largest and most rigid of these are the annulus fibrosus, posterior longitudinal ligament, and capsular ligament. By virtue of their size and certain biomechanical observations, these ligaments stabilize the cervical spine. The other ligaments play a more specialized and secondary role. The intertransverse ligaments, although thin and frail, are consistently found and appear to limit rotation and lateral bending, the anterior longitudinal ligament limits extension and the interspinous and supraspinous ligaments limit spinal flexion. Under physiologic conditions, the elastic ligamentum flavum permits extension of the spine without impinging upon the spinal cord or nerve roots. As a group, the ligaments of the cervical spine control motion within finite limits without jeopardizing spinal cord or nerve root function.     

腰椎间盘突出症再手术原因分析和手术方式探讨

目的:探讨腰椎间盘突出症再手术的原因及手术方式。方法:对39例腰椎间盘突出症术后症状无改善或缓解一段时间后复发需再手术的患者进行分析和总结。再手术方式:椎板间开窗或经原椎板间扩大开窗、椎间盘切除8例;半椎板切除减压、椎间盘切除3例;全椎板切除减压、椎间盘切除27例(其中23例行后路椎弓根内固定加横突间植骨融合,2例同时行椎间cage置入融合);经左前外侧入路腹膜外椎间盘切除、椎间植骨融合1例。结果:再手术原因包括复发性腰椎间盘突出20例、相邻节段腰椎间盘突出7例、腰椎节段性不稳定8例和腰椎间盘未彻底去除4例,其中合并继发性腰椎管狭窄8例,硬膜外瘢痕形成4例。术中发生脑脊液漏4例,均行硬膜修补,术后恢复良好。随访1年6个月～5年7个月,其中31例患者症状明显改善,7例症状部分改善,1例无改善,优良率为79.5%。再手术前JOA评分平均11.8分,再手术后末次随访时平均25.6分,有显著性差异(P<0.05),恢复率为80.2%。23例行椎弓根内固定加横突间植骨融合患者末次随访时植骨融合率为70%,1例行椎间植骨融合患者末次随访时植骨融合。结论:腰椎间盘突出症再手术的主要原因为复发性腰椎间盘突出、相邻节段腰椎间盘突出、腰椎节段性不稳定和腰椎间盘未彻底去除等,正确分析再手术原因并选择合理的手术方式,仍可以取得较为满意的疗效。     

Cage联合SF在腰椎间盘突出合并椎管狭窄中的应用

目的 探讨Cage联合SF在冶疗腰椎间盘突出合并椎管狭窄中的应用价值。方法 采用全椎板切除减压Cage自体骨植入联合SF内固定治疗腰椎间盘突出合并椎管狭窄22例。结果 随访22例，随访时间平均40个月，脊柱均满意融合。根据Nakai评分，优13例，良7例，可2例。结论 Cage、SF联合应用在冶疗腰椎间盘突出合并椎管狭窄中疗效显著，能提供良好的脊柱稳定性和满意的脊柱融合率，符合腰椎的生物力学。     

重建椎管后部结构治疗腰椎管狭窄症

目的 介绍一种应用劈开截骨，以黄韧带为轴保留棘突、椎板和外层黄韧带行椎板回植，重建完整椎管后部结构和硬膜外腔的椎管重建术治疗腰椎管狭窄症的后路手术技术，并评价效果。方法 2001年10月～2003年4月，应用椎管重建术治疗腰椎管狭窄症39例，男19例，女20例。年龄36～77岁，平均49．6岁。病变椎体为L3、4～L5S15例，L4、5～L5S418例，L4、511例，L5S15例；病程3个月～16年，平均40．3个月。术中纵行劈开棘突，将上位椎板的下1／2梯形截断后，连同黄韧带浅层向尾侧翻开，切除深层黄韧带、两侧侧隐窝椎板的内层和增生的关节突，椎管扩大后，原位缝合截开的椎板。术后1周、3个月及1年行CT检查，并于术后1年进行疗效评定。结果 39例术后均获18～36个月随访。术后1周CT示椎管及神经根管扩大满意，术后3个月复查CT示87．2％（34／39）椎板和棘突已达骨性融合，术后1年CT示所有患者椎板原位固定融合，黄韧带愈合，无再狭窄。按标准量化评分，术后疗效评定优良率为92.3％（36／39）。结论 此术式保留了棘突、棘间韧带、椎板和黄韧带的连续性，重建完整的硬膜外腔和椎管的后部结构，阻挡了肌肉与神经组织的瘢痕粘连。截骨范围小、保留血液供给、固定方法简便、术后骨愈合时间短及腰椎稳定。     

Surgical treatment of adjacent instability after lumbar spine fusion.

STUDY DESIGN: This study is a retrospective review of 39 patients with previous instrumented lumbar fusion who underwent secondary spine surgery for lumbar adjacent instability. To the authors' knowledge, this is the largest study of surgical treatment of lumbar adjacent instability in the literature to date. OBJECT: This study evaluated the feasibility of adjacent instability treated with medial facetectomy, fusion with autologous bone grafting, and pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA: The surgical treatment of adjacent instability has seldom been discussed. Revision spine fusions are challenged by high pseudarthrosis rates. METHODS: Thirty-nine patients with previous lumbar fusion underwent second lumbar spine surgery for adjacent instability. All were treated with autogenous posterolateral arthrodesis and transpedicle screw fixation in addition to decompressive laminectomy. Medical records, radiographs, and pain scores were obtained. RESULTS: The clinical results were excellent or good in 76.9% of patients, and the radiographic fusion was successful in 37 (94.9%) of patients. Flat back was noted in 8 (20.5%) of patients. In 5 patients (12.8%), neighboring segment breakdown again developed, and 2 of those patients underwent a third lumbar fusion. Dural tear during operation occurred in 2 patients. One patient experienced cauda equina syndrome but recovered bladder function 1 month later. CONCLUSION: Autogenous posterolateral arthrodesis combined with pedicle screw fixation led to successful radiologic and clinical outcome in patients with lumbar adjacent instability. Adequate decompression of the adjacent stenosis requires medial facetectomy, thus preventing aggressive nerve root manipulation and reducing the incidence of dural tear.