Management of thoracolumbar fractures with accompanying neurological injury.

The optimal surgical approach for spinal canal reconstruction of thoracolumbar fractures is controversial, and the relationship between spinal canal reconstruction and neurological recovery remains unclear. To address these issues, 22 consecutive cases of thoracolumbar fracture with accompanying neurological deficit were reviewed. Neurological status was graded at the time of admission, postoperatively, and at a mean of 15 months postinjury. By using preoperative and postoperative radiographs and computed tomographic scans, the degree of spinal canal compromise was quantified in the sagittal, coronal, and axial planes. All fractures were stabilized by posterior instrumentation and fusion, and in 10 injuries, retropulsed vertebral body fragments were further reduced by posterolateral decompression. Spinal canal dimensions, neurological function, and operative approach were compared by using nonparametric statistical analysis. The greater the initial spinal canal compromise, the more severe the neurological deficit (P = 0.04). With injuries involving L1 and above, this relationship increased (P = 0.003). The extent of spinal canal reconstruction failed to correlate with neurological recovery. Compared with spinal instrumentation alone, transpedicular decompression showed no benefit in terms of postoperative canal dimensions or neurological outcome. On the basis of this experience, transpedicular decompression offers no advantage over spinal instrumentation alone. The relationship between initial spinal canal encroachment and neurological deficit demonstrates that the degrees of bony and neurological injury directly reflect the kinetic energy transferred at the time of impact. The lack of correlation between the extent of spinal canal reconstruction and neurological recovery suggests that ongoing neural compression/distortion contributes little to the overall neurological injury.     

Modified transpedicular approach for the surgical treatment of severe thoracolumbar or lumbar burst fractures.

BACKGROUND CONTEXT: Conventional transpedicular decompression of the neural canal requires a considerable amount of lamina, facet joint and pedicle resection. The authors assumed that it would be possible to remove the retropulsed bone fragment by carving the pedicle with a high-speed drill without destroying the vertebral elements contributing to spinal stabilization. In this way, surgical treatment of unstable burst fractures can be performed less invasively. PURPOSE: The purpose of this study is to demonstrate both the possibility of neural canal decompression through a transpedicular approach without removing the posterior vertebral elements, which contribute to spinal stabilization, and the adequacy of posterior stabilization of severe vertebral deformities after burst fractures. STUDY DESIGN: Twenty-eight consecutive patients with complete or incomplete neurological deficits as a result of the thoracolumbar burst fractures were included in this study. All patients had severe spinal canal compromise (mean, 59.53%+/-14.92) and loss of vertebral body height (mean, 45.14%+/-7.19). Each patient was investigated for neural canal compromise, degree of kyphosis at fracture level and fusion after operation by computed tomography and direct roentgenograms taken preoperatively, early postoperatively and late postoperatively. The neurological condition of the patients was recorded in the early and late postoperative period according to Benzel-Larson grading systems. The outcome of the study was evaluated with regard to the adequate neural canal decompression, fusion and reoperation percents and neurological improvement. METHODS: Modified transpedicular approach includes drilling the pedicle for removal of retropulsed bone fragment under surgical microscope without damaging the anatomic continuity of posterior column. Stabilization with pedicle screw fixation and posterior fusion with otogenous bone chips were done after this decompression procedure at all 28 patients included in this study. RESULTS: Twenty-three of 28 patients showed neurological improvement. The percent of ambulatory patients was 71.4% 6 months after the operation. The major complications included pseudarthrosis in five patients (17.8%), epidural hematoma in one (3.5%) and inadequate decompression in one (3.5%). These patients were reoperated on by means of an anterior approach. Of the five pseudarthrosis cases, two were the result of infection. CONCLUSION: Although anterior vertebrectomy and fusion is generally recommended for burst fractures causing canal compromise, in these patients adequate neural canal decompression can also be achieved by a modified transpedicular approach less invasively.     

Management of lumbar translocation injuries: case reports

Lumbar translocation (complete lumbar dislocation) injuries constitute a severe and highly unstable form of thoraco-lumbar spinal injury and are uncommon. Adequate management of such injuries includes removing the neural tissue compression and realigning and stabilizing the spine. Computerized axial tomographic scans of the spine are very dramatic in demonstrating encroachment on the spinal canal by bony fragments. We report two cases of lumbar translocation injuries with favorable outcomes. The patients were initially managed with halo-femoral traction, resulting in spinal reduction and eliminating the need for acute surgical intervention, and subsequently underwent posterior fusion for stability. Anterior decompression was done at a later date as computed tomography showed retropulsed intracanalicular bone fragments. The use of Harrington rod instrumentation and realignment of the spine did not free the canal of bony fragments and, hence, decompression was required.     

经枕颈后外侧入路齿状突切除治疗寰枢椎陈旧性脱位

目的　为解决难复性寰枢椎陈旧性脱位的外科治疗,探索手术入路措施。方法采用经枕颈后外侧入路切除齿状突并一期行枕颈融合治疗难复性寰枢椎陈旧性脱位5例。结果5 例手术经过顺利,术后神经症状均有明显改善,肌力均有一级以上恢复。无感染及死亡。结论　对难复性寰枢椎陈旧性脱位,尤其是压迫因素来自前方者,经枕颈后外侧入路切除齿状突和颈2 椎体后上份,能同时达到脊髓前、后方彻底减压及一期枕颈融合。此手术入路齿状突显露清楚,手术操作简便、安全。是一种较理想的手术方法。     

Burst fractures of the thoracic and lumbar spine

A burst fracture may be defined as an unstable compression fracture of the posterior wall of the vertebral body that allows fragments to be retropulsed into the spinal canal. Computerized axial tomography evaluation of these injuries often reveals posterior element fracture heretofore not stressed in the literature. In surgical treatment for these injuries four important considerations must be met; (1) the coronal and sagittal alignment of the spine; (2) patency of the neural canal; (3) the two-column concept of spinal stability; and (4) bony vertebral body reconstitution. An algorithm for treatment may be developed with the aid of these principles. Distraction and the creation of spinal lordosis are necessary for reduction.     

椎弓根钉内固定治疗多节段胸腰椎骨折

目的探讨多节段胸腰椎复杂骨折手术治疗效果。方法采用后路长节段椎弓根钉系统复位固定方法,恢复伤椎高度及脊柱生理弯曲,使后纵韧带复张,椎管间接减压或有限椎板切除减压、植骨融合治疗胸腰椎多节段骨折21例。结果术后椎体高度、脊柱生理弧度明显恢复。21例均获随访,时间3个月～6年。椎体高度无明显丢失,无断钉、断棒。Frankel分级：A级2例恢复至B级1例、1例无恢复;B级3例恢复至C级1例、D级1例、1例无恢复;C级5例恢复至D级3例、E级2例;D级5例恢复至E级3例、2例无恢复;E级6例仍为E级。结论多节段胸腰椎骨折影响脊柱稳定性,后路长节段椎弓根钉系统复位固定能够恢复脊柱稳定性及生理弧度,为改善神经功能提供条件。     

Single-stage posterolateral transpedicle approach for spondylectomy, epidural decompression, and circumferential fusion of spinal metastases

STUDY DESIGN: Retrospective review of prospectively maintained institutional spine database. OBJECTIVES: To assess the pain, neurologic, and functional outcome of patients with metastatic spinal cord compression using a posterolateral transpedicular approach with circumferential fusion. SUMMARY OF BACKGROUND DATA: Patients with spinal metastases often have patterns of disease requiring both an anterior and posterior surgical decompression and spinal fusion. For patients whose concurrent illness or previous surgery makes an anterior approach difficult, a posterior transpedicular approach was used to resect the involved vertebral bodies, posterior elements, and epidural tumor. This approach provides exposure sufficient to decompress and instrument the anterior and posterior columns. METHODS: During the past 15 months, 25 patients were operated on using a posterolateral transpedicular approach. The primary indications for surgery were back pain (15 patients) and neurologic progression (10 patients). All patients had vertebral body disease, and 21 patients had high-grade spinal cord compression from epidural disease as assessed by magnetic resonance imaging. Seven patients underwent preoperative embolization for vascular tumors. In each patient, the anterior column was reconstructed with polymethyl methacrylate and Steinmann pins and the posterior column with long segmental fixation. RESULTS: All patients achieved immediate stability. Pain relief was significant in all 23 patients who had had moderate or severe pain. Neurologic symptoms were stable or improved in 23 patients. One patient with an acutely evolving myelopathy was immediately worse after surgery, and one patient had a delayed neurologic worsening, progressing to paraplegia. CONCLUSIONS: The posterolateral transpedicular approach provides a wide surgical exposure to decompress and instrument the anterior and posterior spine. This technique avoids the morbidity associated with anterior approaches and provides immediate stability. Vascular tumors may be removed safely after embolization. Patients can be mobilized early after surgery.     

Management of cervical spinal fractures in ankylosing spondylitis with posterior fixation

STUDY DESIGN: Introduction of a posterior approach for internal fixation of fractures of the ankylosed cervical spine. OBJECTIVES: To evaluate the clinical outcome of patients with ankylosing spondylitis and cervical spinal fractures treated with posterior instrumentation and a collar orthosis. SUMMARY OF BACKGROUND DATA: Cervical spinal fractures in patients with ankylosing spondylitis almost always extend completely across the vertebral segment to include both anterior and posterior elements. Treatment with immobilization alone is often inadequate. Generalized spinal rigidity and exaggerated thoracic kyphosis may hinder anterior exposure. Posterior approaches have been described but generally require postoperative halo immobilization. In the authors' technique for patients whose spinal alignment is relatively well preserved, a posterior exposure is used that achieves three-point internal fixation along multiple segments. The complications associated with halo immobilization are avoided. METHODS: Seven patients with ankylosing spondylitis and fractures of the cervical spine were stabilized with posterior instrumentation. Patients were immobilized after surgery with either a cervical collar or a sternal occipital mandibular immobilizing brace and observed for neurologic outcome, radiographic evidence of bony fusion, and complications. RESULTS: No patient experienced neurologic deterioration with surgery. Two patients died at acute rehabilitative facilities after discharge. Radiographic evidence of fusion was observed in the five patients available for follow-up. CONCLUSIONS: Patients with ankylosing spondylitis and cervical spinal fractures can be adequately treated with lateral mass plating and interspinous wiring of autologous rib graft. Adequate postoperative immobilization can be attained with a cervical collar and does not require a halo vest.     

Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament

Laminectomy, which had long been used for treatment of cervical spondylotic myelopathy, including ossification of the longitudinal ligament in the cervical spine, had numerous complications such as postoperative malalignment of the cervical spine and vulnerability of the spinal cord caused by total removal of the posterior structures. In 1977 Hirabayashi devised an open door expansive laminoplasty, which is a relatively easier and safer procedure than laminectomy, that eliminated such problems by preserving the posterior elements. The decompression effect of the expansive laminoplasty against a compressed spinal cord is comparable with that of laminectomy and anterior decompression followed by fusion, whereas the expansive laminoplasty has no structural problems and adverse effects on adjacent disc levels that often are associated with anterior decompression followed by fusion. Average recovery rate of expansive laminoplasty for cervical spondylotic myelopathy has been reported to be approximately 60% (Japanese Orthopaedic Association score) and with long term stability. At present, authors consider all patients with cervical spondylotic myelopathy candidates for expansive laminoplasty except for those having preoperative kyphosis and single level lesion without canal stenosis. Two remaining problems of expansive laminoplasty to be solved are prevention of C5,C6 radicular pain and/or paresis, the most frequent complication that occurs in approximately 5% to 10% of the patients, although most complications resolve spontaneously within 2 years, and correction of nonlordotic alignment to lordosis which are essential for posterior decompression effect of expansive laminoplasty by allowing the spinal cord to shift dorsally.     

Posterior segmental spinal instrumentation (PSSI) with posterolateral decompression and debulking for metastatic thoracic and lumbar spine disease. Limitations of the technique

Twenty-five patients with metastatic thoracic and lumbar spine disease were initially treated by the authors with posterolateral debridement and decompression, along with posterior segmental spinal instrumentation. Ten patients had marked paresis, nine had signs of spinal cord or cauda equina compression without paresis, and all patients had pain severe enough to prevent sitting/standing/walking. The posterior approach was used in these patients instead of an anterior one because of translocation (4), three-column disease (16), three or more vertebral bodies involved (13), disease at two separate locations (2), and inability to tolerate an anterior approach (3). All patients had maintenance of spinal alignment for the length of follow-up or until their ultimate demise. Good pain relief was achieved in 19 of 25 patients. Six of ten patients with significant paresis recovered. Four patients developed recurrent spinal cord compression within 12 months postoperative from regrowth of tumor that was not controlled by radiotherapy or chemotherapy. Six of the 25 patients were not significantly palliated by the technique.     

What bone graft substitutes should we use in post-traumatic spinal fusion?

Surgical treatment of spinal fractures consists of postural reduction and segmental arthrodesis, together with an eventual performance of spinal canal decompression. Spinal arthrodesis consists of the combination of a hardware system for mechanical stabilisation together with a biological substance for enhancement of bone formation. To date, autologous graft is the only biological substance demonstrated to possess osteogenic properties. Cancellous bone graft has greater cellular activity than cortical graft, whereas cortical graft is stronger. Consequently, according to biological and biomechanical properties of autograft, spinal posterior arthrodesis is better enhanced by cancellous autograft, whereas anterior interbody tricortical bone is more suitable for anterior fusion. Allograft does not cause harvesting complications as autograft does, and also its amount is theoretically unlimited; nevertheless the rate of bone fusion facilitated by allograft is far from that enhanced by autograft given that allograft has no osteoprogenitor cells. There is little evidence on the efficacy of demineralised bone matrix for spinal fusion. Bone morphogenetic proteins (BMPs) are in use in spinal surgery, but their exact role with respect to type, dose, and carrier, together with their cost-effectiveness, need further clinical delineation. Calcium phosphate compounds appear to be good as carriers; however, they have no osteoinductive or osteogenic properties. Current clinical literature seem to indicate their usefulness for bony fusion in spinal surgery, when combined with bone marrow aspirate or used as an extender for autologous bone graft. Age, length of fusion, location, and concurrent diseases should be definitive for fusion outcome; papers on spinal arthrodesis should neatly stratify these variables. Unfortunately, since that is not the rule, conclusions drawn from current literature are very unreliable. Autograft remains the gold standard, and cancellous bone is advisable in posterolateral approaches, whereas tricortical iliac crest autograft appears appropriate for interbody support. In longer segments, its expansion with BMPs looks safe at least. Basic knowledge has been achieved from animal experiments, and clinical application of the findings to humans should be done very cautiously; in any case, both anterior and posterior arthrodesis must be protected with instrumentation used according to appropriate biomechanical principles. A combination of failure of the correct graft together with proper instrumentation will result in poorer outcome, even if the right graft is used.     

Laminectomy combined with posterolateral stabilisation: a muscle-sparing approach to the lumbosacral spine

Summary We report our experience with a technique of midline posterior decompression in combination with the Wiltse muscle splitting approach for posterolateral spinal fusion and pedicle screw fixation. The technique is suitable for cases of lumbar spinal stenosis and dise herniation where stabilisation is required and has significant advantages over other reported methods. This combined approach has been used in 52 patients since 1990 with no complications from the approach itself.     

多节段胸腰椎脊柱骨折的手术治疗

目的探讨椎弓根钉棒系统治疗多节段胸腰椎脊柱骨折的手术方式与疗效。方法采用后路切开复位、椎弓根钉棒系统内固定、选择性椎管减压及后外侧植骨融合手术治疗44例多节段胸腰椎骨折患者,对患者术前与随访时的ASIA分级、伤椎椎体高度矫正率进行分析。结果全部患者平均随访12个月,未发现内固定物松动、断裂,椎体高度由术前平均49.3%恢复至术后平均92.5%。ASIA分级较术前平均提高1.2级。结论后路切开复位、椎弓根钉棒系统内固定基础上选择性椎管减压＋植骨融合是治疗多节段胸腰椎脊柱骨折的理想选择。     

Intraoperative ultrasonography (IOUS) in thoracolumbar fractures

The thoracolumbar levels are the second most common region for spinal trauma. A major surgical effort often entails removal of retropulsed bone fragments with decompression of the spinal contents or realignment of vertebral subluxations. The ability to determine intraoperatively the completeness of such a procedure could impact on the surgical approach and, ultimately, the operative result. The intraoperative use of ultrasonography has gained popularity and applicability. This comparison study of intraoperative ultrasonography versus postoperative computed tomography (CT) assessed the accuracy of intraoperative ultrasonography in determining the status of the spinal canal following surgical intervention in a group of 21 patients with thoracolumbar fractures. In all cases a patent ventral subarachnoid space or complete spinal canal decompression was deduced following intraoperative ultrasonography. The postoperative assessment by CT concurred in 20 of 21 (95%) situations. Intraoperative ultrasonography proved useful during the operative management of these fractures and gave good supportive evidence that the neural elements were decompressed by surgical procedure.     

Z-plate instrumentation in thoracolumbar spinal fractures.

Anterior decompression enables direct access and good canal clearance of the injury level in thoracolumbar spinal fractures, and decompressing the neural elements is shown to be an important factor for neurologic improvement and pain relief in many cases. In this study, results with anterior decompression and Z-plate instrumentation in thoracolumbar spinal fractures are reviewed. Nineteen patients with old spinal fracture (average: 3 years) and neural compression, and 15 patients with fresh thoracolumbar fractures with neurologic deficit and/or major anterior spinal canal obstruction had anterior decompression and Z-plate instrumentation with anterior fusion. Stabilization was protected with thoracolumbar thermoplastic braces for six months. Preoperative kyphotic deformity averaged 20.9 degrees (range: 7 degrees to 64 degrees), while it was an average of 8.0 degrees (range: -12 degrees to 35 degrees) postoperatively. Medullary canal compromise was 41% an average (range: 13% to 67%) and postoperatively it had an average value of 6% (range: 0% to 18%). Patients were followed up an average of 30 months (range: 25 to 36 months). The unchanged positions of bone grafts and statistically insignificant loss of correction in the sagittal plane are accepted as evidence for bony fusion in all patients. Z-plate instrumentation provides stable fixation. Additionally, the technique can be performed easily and has the added benefit of being MRI-compatible.     

Complete rotational burst fracture of the third lumbar vertebra managed by posterior surgery. A case report

STUDY DESIGN: Case report of a young man with rotational burst fracture of the third lumbar vertebra, treated by posterior surgery. OBJECTIVES: To describe the management of a rotational burst fracture of the third lumbar vertebra by posterior surgery consisting of reduction, decompression, fusion, and transpedicular instrumentation. SUMMARY OF BACKGROUND DATA: Surgery is the generally recommended means of managing lumbar burst fractures with neurologic deficit. Some surgeons recommend anterior decompression, fusion, and instrumentation. Posterior surgery with decompression through laminectomy, spongioplasty of the vertebral body, interbody fusion of damaged discs, posterolateral fusion, and transpedicular fixation is also a safe and successful management technique. The combined approach consists of posterior decompression, fusion, transpedicular fixation, and anterior fusion using pelvic autografts. The optimum method of management remains in question. METHOD: An 18-year-old man with complete rotational burst fracture of the third lumbar vertebra was treated by posterior surgery. This surgery consisted of reduction, laminectomy, decompression, structure of dural sac tears, spongioplasty of the vertebral body, interbody fusion of both damaged discs, and the implantation of a transpedicular Socon fixator (Aesculap, Tuttlingen, Germany), including a transverse connector. The case was documented by radiographs and computed tomography scans before surgery and after fixator removal 19 months after surgery. RESULTS: The patient healed solidly with no instrumentation failure. The neurologic deficit Frankel Grade B improved to Frankel Grade D. CONCLUSION: Surgery to manage lumbar burst fracture must include reduction, decompression, restoration and fusion of anterior and posterior elements by using autologous pelvic spongious autografts, and anterior or posterior instrumentation. Posterior surgery including suturing of dural sac tears, fusion of damaged structures, and transpedicular fixation is successful in young patients and patients with good bone quality.     

不可复性寰枢椎脱位的临床分型及术式选择

 目的 探讨不可复性寰枢椎脱位（寰枢椎脱位且其间存在骨性融合）的临床分型及其术式选择策略。方法 2002年11月至2013年12月,收治不可复性寰枢椎脱位患者 20例,男8例,女12例;年龄22~57岁,平均39岁;6例无手术史,14例有手术史（前路手术史1例、后路手术史11例、前后路联合手术史2例）,其中13例残留内固定物（1例残留寰枢椎前路钢板、12例残留寰枢椎后路钉棒）。根据骨性融合范围、位置分为广泛融合型和点状融合型。在气管插管全麻下施行手术,点状融合型采取软组织松解、骨性融合点解除、复位、固定和融合手术;广泛融合型采用直接减压而不进行复位和固定。术后1周、3、6、12个月及之后每年随访时均行X线、CT和MR检查,以观察寰枢椎间复位、内固定、植骨融合和脊髓减压情况。临床评价采用日本骨科协会（ Japanese Orthopaedic Association Scores,JOA）评分。结果20例患者中广泛融合型5例,点状融合型15例;自发性融合6例,医原性融合14例（3例为广泛融合型、11例为点状融合型）。5例广泛融合型患者经口前路切除寰椎前弓和齿突减压,术后MRI示脊髓压迫完全消除;15例点状融合型患者术后均获得复位。术中均未出现脊髓及椎动脉损伤。1例患者术后出现脑脊液漏,经清创、取出前路内固定,改行后路内固定后治愈。5例广泛融合型和14例点状融合型获得随访,随访时间6~72个月,平均38个月。JOA评分由术前平均11分恢复至末次随访时平均14分。5例广泛融合型患者虽未附加内固定,随访期间均未出现寰枢椎间失稳;14例点状融合型患者术后6个月寰枢椎侧块间植骨均融合。结论 点状融合型患者经彻底松解和解除骨性融合后可获得复位,广泛融合型患者通过减压仍可获得较好的疗效。     

Ⅰ期前后联合手术入路治疗严重下颈椎骨折脱位

目的探讨一期前后联合手术入路治疗严重下颈椎骨折脱位合并脊髓损伤的临床疗效。方法回顾性分析2003年6月～2008年6月一期前后联合手术复位、减压和内固定治疗76例严重下颈椎骨折脱位合并脊髓损伤的患者。对手术时间、术中出血量、术中术后并发症和术后神经功能恢复情况等进行分析。结果76例患者术后随访6～28个月,平均12个月,术后神经功能评价按Frankel分级,均有1～2个级别恢复,术前A级10例,B级24例,C级31例,D级11例;术后A级4例,B级8例,C级27例,D级24例,E级13例。植骨均在6个月获得骨性融合。本组未出现内固定断裂、松动及脱出,无血管、神经、食道损伤等并发症。结论严重下颈椎骨折脱位选择I期前后路联合手术可完全恢复颈椎序列,椎管前后方压迫得到彻底解除,损伤节段术后获得即刻稳定,能够获得较好的脊髓功能恢复和骨性融合。     

脊髓型颈椎病减压术后疗效及并发症分析

目的 通过脊髓型颈椎病采用不同术式治疗后脊髓功能改善及患者预后状况的观察,探讨术后并发症及"弓弦效应"产生机制.方法 回顾性分析2001年1月至2002年10月收治的经前路减压并获随访的56例和后路减压后获得随访的62例患者,随访时间均在24个月以上,于术前、术后3个月(早期)及24个月以上(中期)行脊髓功能JOA评分、体感诱发电位和颈椎主动活动度检查,对比两组减压术后早、中期疗效.结果 获得随访的118例患者,前路手术56例中优14例(25%).良29例(51.79%),可10例(17.86%),差3例(5.36%);后路手术62例中优23例(37.10%),良31例(50%),可7例(11.29%),差1例(1.61%).前、后路减压术后不同时间JOA评分改善率与SEP波幅、潜伏期变动率差异有统计学意义;两种减压术后颈椎各向主动活动度差异有统计学意义.发生术后并发症的前路组7例和后路组13例,经保守治疗后逐渐缓解.结论 (1)仅以"C5神经根麻痹"概念解释上述术后不适症状较牵强,应系术中脊髓内组织受损所致;(2)后路椎板减压因直接扩大椎管容积及产生"弓弦效应",较前路手术同期脊髓功能恢复效果更显著;(3)后路术后颈椎主动活动度较一般人群有轻微减小,前路组主动活动度又较后路组有一定程度地下降.     

Posttraumatic atlanto-axial subluxation and myelopathy. Efficacy of anterior decompression

Compression of the neuraxis may occur after displaced fractures of the dens. Nonunion or malunion increases the risk of developing neurologic complications because of the resulting atlanto-axial instability. Posterior decompression has generally been the surgical solution to myelopathy at this level. Two patients with cervical myelopathy due to displaced ununited dens fractures were treated with posterior fossa decompression and high cervical laminectomy. Both patients deteriorated after the surgery. Most of their neurologic deficits finally resolved after microsurgical transoral decompression (by resection of the dens). In those patients in whom atlanto-axial instability causes primarily anterior compression of the neuraxis, especially by a bony lesion, decompression posteriorly may not achieve the desired effect, and, instead, may cause a deterioration in the patient's condition. Anterior atlanto-axial subluxation effectively lengthens the bony spinal canal, which results in stretching of the relatively inelastic spinal cord over the bony deformity. If indirect methods of reduction fail to relieve the condition, then anterior transoral decompression is recommended.