Percutaneous techniques in the thoracic and lumbar spine

Techniques of percutaneous spinal instrumentation have in the meantime become standard methods in many hospitals. While several indications have been established that are excellently suited to this technique, uncertainty prevails for other indications. This contribution intends to clarify the technical prerequisites for performing percutaneous instrumentation in the region of the thoracic and lumbar spine in addition to describing customary indications and various techniques of percutaneous instrumentation. This is combined with a critical assessment of what intrinsically cannot or cannot yet be achieved with a percutaneous approach to illustrate that the percutaneous procedure can by no means be considered a mere evolution of the previous classic open techniques.     

A further development in spinal instrumentation

Summary The purpose of this paper is to describe the concepts and use of a new, versatile instrumentation system, the universal spine system (USS), that has been designed to have wide application for pathology of the thoracolumbar spine. Many instrumentation systems for thoracolumbar spinal surgery now exist that were each originally designed to address specific areas of spinal pathology. For example, the recent systems designed to treat scoliosis deformities do not provide the instrumentation and implant support to adequately address other spinal disorders, such as fractures. In addition, most posterior implant systems were not designed for use anteriorly, and vice versa. As a result, surgeons have been required to become familiar with several different instrumentation systems in order to meet the varied needs of a spinal surgery practice. The objective of designing a new system was to simplify the surgical treatment of the commonly encountered spinal disorders by providing the surgeon with a single set of instruments and implants that could be used to treat tumors, trauma, deformities, and degnerative conditions affecting the thoracolumbar spine, via either an anterior or a posterior approach. This paper describes the development of the concepts, instruments, and implants of the USS and provides examples of its application in several case illustrations.     

Partially Overlapping Limited Anterior and Posterior Instrumentation for Adult Thoracolumbar and Lumbar Scoliosis: A Description of Novel Spinal Instrumentation, “The Hybrid Technique”

Progressive and/or painful adult spinal deformity in the thoracolumbar and lumbar spine is sometimes treated surgically by long posterior fusions from the thoracic spine down to the pelvis, especially where there is a major thoracic curve component. Recent advances in anterior spinal instrumentation and spinal surgery technique have demonstrated the improved corrective ability offered by anterior stabilization systems, and the added benefit of limiting the number of vertebral fusion levels required for control of the deformity. The "hybrid technique" is a novel use of anterior instrumentation that applies limited anterior instrumentation down to the low lumbar spine (rods and screws), and partially overlapping short-segment posterior instrumentation to the sacrum (pedicle screws and rods). These constructs avoid posterior thoracic instrumentation and fusions, and avoid extension of posterior instrumentation to the pelvis. In the first 10 patients treated using this technique, thoracolumbar and lumbar major curve correction has averaged 71 and 82% in the immediate postoperative period (n = 7), respectively, and 59 and 68% at 2-year follow-up, respectively. The technique is an appealing and attractive alternative for treatment of thoracolumbar and lumbar scoliosis in the adult population, and avoids the requirement for applying spinal fixation to the thoracic spine and the pelvis.     

经皮穿刺后路脊柱内固定术治疗胸腰椎骨折

目的 探讨经皮穿刺胸腰椎椎弓根螺钉系统内固定的可行性及临床意义。方法 2002年9月至2003年12月采用经皮穿刺胸腰椎椎弓根螺钉系统内固定，椎管减压，经椎弓根椎体内植骨，治疗胸腰椎骨折16例。结果 手术时间：130—210min，平均162min。术中出血量：20—320ml，平均160ml。手术后节段后凸Cobb角纠正率平均达85．2％。椎体塌陷纠正事平均为80．2％。均在术后3周佩戴腰围支具下床。术后3周复查ASIA分级，C缓恢复至D级3例，D级恢复至E级9例，保持D级2例，保持E级2例。结论 经皮穿刺胸腰椎椎弓根螺钉系统内固定创伤小，可以完成开放手术的所有步骤．但技术难度高、X线暴露时间长。     

Texas Scottish Rite Hospital rod instrumentation for thoracic and lumbar spine trauma

The authors present their experience with 28 patients who had incurred unstable thoracic or lumbar spine fractures and who were intraoperatively stabilized with the Texas Scottish Rite Hospital (TSRH) universal instrumentation system. These patients were treated over a 1-year period and reflect an evolving insight into the treatment of thoracic and lumbar spine trauma with universal instrumentation. The TSRH instrumentation system appears equivalent to the more established Cotrel-Dubousset system in most respects. The construct design of the TSRH system facilitates the safe application of a rigid spinal implant. No cases of instability or pseudoarthrosis were observed during an average follow-up period of 9 months, (minimum 3 months). As the surgical treatment plan evolved, shorter and more compact constructs were increasingly utilized. There were no cases of instrumentation failure, regardless of the number of spinal levels fused or the number of levels instrumented. The value of using short rods when possible is emphasized: they may decrease the incidence of delayed instability and discomfort related to loosening at the hook/bone interface compared to that observed when long-rod systems are used in association with short spine fusions causing a fusion/instrumentation mismatch.     

Long-term three-dimensional changes of the spine after posterior spinal instrumentation and fusion in adolescent idiopathic scoliosis

This is a prospective study comparing the short- and long-term three-dimensional (3D) changes in shape, length and balance of the spine after spinal instrumentation and fusion in a group of adolescents with idiopathic scoliosis. The objective of the study was to evaluate the stability over time of the postoperative changes of the spine after instrumentation with multi rod, hook and screw instrumentation systems. Thirty adolescents (average age: 14.5 ± 1.6 years) undergoing surgery by a posterior approach had computerized 3D reconstructions of the spine done at an average of 3 days preoperatively (stage I), and 2 months (stage II) and 2,5 years (stage III) after surgery, using a digital multi-planar radiographic technique. Stages I, II and III were compared using various geometrical parameters of spinal length, curve severity, and orientation. Significant improvement of curve magnitude between stages I and II was documented in the frontal plane for thoracic and lumbar curves, as well as in the orientation of the plane of maximum deformity, which was significantly shifted towards the sagittal plane in thoracic curves. However, there was a significant loss of this correction between stages II and III. Slight changes were noted in apical vertebral rotation, in thoracic kyphosis and in lumbar lordosis. Spinal length and height were significantly increased at stage II, but at long-term follow-up spinal length continued to increase while spinal height remained similar. These results indicate that although a significant 3D correction can be obtained after posterior instrumentation and fusion, a significant loss of correction and an increase in spinal length occur in the years following surgery, suggesting that a crankshaft phenomenon may be an important factor altering the long-term 3D correction after posterior instrumentation of the spine for idiopathic scoliosis. Received: 3 March 1998 Revised: 22 August 1998 Accepted: 15 September 1998     

A biomechanical analysis of Zielke, Kaneda, and Cotrel-Dubousset instrumentations in thoracolumbar scoliosis. A calf spine model.

A biomechanical study was performed in order to evaluate the initial stability of three spinal instrumentation systems, applied to a scoliosis model. Five calf spines (T11-L2) were destabilized anteriorly, and, by inserting a wedge-shaped resin disc within each destabilized intervertebral space, a thoracolumbar scoliosis was created. Three spinal instrumentation systems (Zielke anterior instrumentation, Kaneda anterior multisegmental fixation device, and Cotrel-Dubousset posterior instrumentation) were applied to correct the simulated scoliotic condition. Mechanical nondestructive cyclical testing in axial compression, rotation, flexion, and extension was performed on each spinal construct. The Kaneda device was the most stable instrumentation in all four loading conditions. Zielke instrumentation failed to restore the stability to the level of the intact spine in rotation, and was the least rigid instrumentation in flexion and extension. The Cotrel-Dubousset instrumentation demonstrated favorable stability in flexion and extension, but became the least rigid instrumentation in axial compression and rotation. This study suggests that a one-stage procedure with Zielke instrumentation and a two-stage procedure (anterior release with bone graft and posterior stabilization) with Cotrel-Dubousset instrumentation applied for the correction of scoliosis, should be supplemented with additional external or internal supports. The Kaneda device may offer enough stability with an anterior procedure alone in the correction of scoliosis.     

Image-guided multilevel vertebral osteotomies for en bloc resection of giant cell tumor of the thoracic spine: case report and description of operative technique

The use of frameless stereotactic navigation is gaining popularity in spinal surgery. Although initially used in the spine for placement of lumbar pedicle screws, this technology has expanded to facilitate placement of spinal instrumentation at virtually all spinal levels. While previous reports have described the utility of image guidance for placement of spinal instrumentation, its use in assisting with resection of complex spine tumors has not been extensively reported. Here we describe the use of frameless stereotaxy to guide a complex, four-level sagittal vertebral osteotomy for en bloc resection of a giant cell tumor involving the chest wall and thoracic spine.     

Neon--a new angle-stable implant system for dorsal occipitocervical instrumentation. Biomechanical comparison with established systems

Posterior instrumentation of the occipitocervical spine is well-established for different indications. The aim of this study was to evaluate whether posterior internal fixation of the occipitocervical spine with the new implant system improves primary biomechanical stability. Primary stability was significantly increased in all load cases with the new modular implant system compared to the other implant systems. Pedicle screw instrumentation tended to be stabler compared to lateral mass screws; nevertheless, significant differences could be observed only for lateral bending. As the experimental design precluded any cyclic testing, the data represent only the primary stability of the implants. In summary, this study showed that posterior instrumentation of the cervical spine using the new neon occipito-cervical system improves primary biomechanical stability compared to the CerviFix system and the Olerud cervical rod spinal system.     

A three-dimensional radiographic comparison of Cotrel-Dubousset and Colorado instrumentations for the correction of idiopathic scoliosis

STUDY DESIGN: A prospective clinical study comparing two instrumentation systems for the correction of idiopathic scoliosis. OBJECTIVES: To measure the short-term three-dimensional changes in the shape of the spine after corrective surgery and compare the Cotrel-Dubousset instrumentation to the more recent Colorado instrumentation to determine whether one system provides better three-dimensional correction. SUMMARY OF BACKGROUND DATA: Adequate three-dimensional correction of scoliotic deformities has been reported with the Cortrel-Dubousset instrumentation system. During the past decade, a new generation of more versatile and user-friendly spinal implants has appeared, but there are no reports available to indicate whether similar or better correction can be obtained with these newer systems. METHODS: The three-dimensional geometry of the thoracic and lumbar spine was documented in the standing position using a three-dimensional reconstruction technique based on multiplanar radiography in 67 adolescents with idiopathic scoliosis undergoing correction by a posterior approach. Changes in spinal shape were measured 3 days before and 1 month after the surgery in 31 patients with Cotrel-Dubousset instrumentation and 36 patients with Colorado instrumentation. RESULTS: In both groups, adequate three-dimensional correction of the scoliotic deformities was documented for thoracic and lumbar curves, with significant changes in the frontal plane, in the plane of maximum curvature, and in its orientation. When comparing both groups, better correction was obtained in the frontal plane with the Colorado instrumentation (65% vs. 48% with Cotrel-Dubousset), a finding that may be explained by the significantly greater proportion of pedicle screws used in this group. CONCLUSION: Both instrumentation techniques achieve an effective and comparable three-dimensional correction of the scoliotic deformities.     

The stability of reconstruction methods after thoracolumbar total spondylectomy. An in vitro investigation.

STUDY DESIGN: After total spondylectomy, five types of spinal reconstruction techniques were compared biomechanically. OBJECTIVES: To evaluate the stability provided by five reconstruction methods after total spondylectomy. SUMMARY OF BACKGROUND DATA: Total spondylectomy presents a worst-case scenario for spinal reconstruction. However, few investigators have biomechanically investigated spinal reconstruction stability after total spondylectomy. METHODS: Eight human cadaveric spines (T11-L5) were used. After intact analysis, a total spondylectomy was performed at L2 and reconstructed using Harms titanium mesh (Depuy-Motech, Warsaw, IN) as an anterior strut. Anterior, posterior, or circumferential instrumentation techniques were then performed using the Kaneda SR and ISOLA pedicle screw systems (AcroMed Corp., Cleveland, OH) as follows: 1) anterior instrumentation at L1-L3 with multisegmental posterior instrumentation at T12-L4 (AMP), 2) anterior instrumentation at L1-L3 with short posterior instrumentation at L1-L3 (ASP), 3) anterior instrumentation at L1-L3 (A), 4) multilevel posterior instrumentation at T12-L4 (MP), and 5) short posterior instrumentation at L1-L3 (SP). Nondestructive biomechanical testing was performed under axial compression, flexion-extension, and lateral bending loading modes. RESULTS: Only circumferential instrumentation techniques (AMP, ASP) exhibited higher stiffness than the intact spine in all loading modes (P < 0.05). Short circumferential fixation provided more stability than did multilevel posterior instrumentation (P < 0.05). Multilevel posterior fixation provided more stiffness than did short posterior and anterior instrumentation alone (P < 0.05). CONCLUSIONS: Only circumferential fixation techniques provide more stability than the intact spine in all testing modes. Short circumferential instrumentation provides more stability than multilevel posterior instrumentation alone and requires fewer levels of spinal fusion.     

Percutaneous multilevel decompressive laminectomy, foraminotomy, and instrumented fusion for cervical spondylotic radiculopathy and myelopathy: assessment of feasibility and surgical technique

OBJECT: Extensive muscle dissection associated with conventional dorsal approaches to the cervical spine frequently results in local pain, muscle wasting, and temporarily painful and restricted neck movement. The utility of a percutaneous muscle-sparing access technique and specifically modified instrumentation for multilevel posterior cervical decompression and fusion were evaluated. METHODS: Eleven patients (six men, five woman; mean age 72.8 +/- 6.3 years) presenting with refractory neck pain and progressive multilevel cervical radiculopathy and/or myelopathy due to cervical spondylosis with spinal canal and neural foraminal stenosis underwent multilevel laminectomy, foraminotomy, and subsequent instrumented posterior fusion via bilateral or unilateral percutaneous muscle dilation approaches. A novel cannulated polyaxial instrumentation system was used for unilateral transpedicular/translaminar fixation. RESULTS: Significant reduction of Neck Disability Index and Nurick Scale scores and partial or complete recovery of upper extremity radicular deficits was observed during follow-up (mean 14.6 months). Mean procedural blood loss was 45.5 ml, and mean length of stay in hospital was 5.7 days. Fusion was demonstrated in 10 patients between 12 and 14 months postoperatively. Operative exposure and instrumentation were significantly facilitated by specific modifications of retractor/access port systems, surgical instruments, and implants. CONCLUSIONS: Muscle sparing posterior decompression and instrumented fusion constitutes a safe and effective surgical option in a selected subgroup of patients with multilevel cervical spondylotic radiculomyelopathy. Specific modifications in surgical technique, instrumentation, and implants are mandatory for effective achievement of the surgical goals. The use of refined image guidance technology and intraoperative imaging can further improve surgical safety and efficacy.     

Spinal Instrumentation With A Low Complication Rate

Background

Spinal instrumentation has become an increasing part of the armamentarium of neurosurgery and neurosurgical training. For noncontroversial indications for spine fusion the arthrodesis rate seems to be better. For both noncontroversial and controversial indications, the reported complication rate with spinal instrumentation tends to be greater than that with noninstrumented spine surgeries. These reported complications include a 2–3% neurologic injury rate, 3–45% reoperation rate for implant failure, and infection rates of 5–10%. Therefore, we report on 299 cases that have undergone spinal instrumentation placed exclusively by neurosurgeons with a very low complication rate.

Methods

Two hundred ninety-nine consecutive spinal instrumentation cases performed exclusively by neurosurgeons at Indiana University Medical Center were analyzed for complications related to spinal instrumentation. The spinal instrumentation placed consisted of 195 anterior cervical locking plates, 22 cases of posterior cervical instrumentation, 9 cases of combined anterior locking plates with posterior cervical instrumentation, 14 anterior thoraco-lumbar plates, 51 posterior thoraco-lumbar instrumentation cases, and 8 combined anterior/posterior thoraco-lumbar instrumentation cases.

Results

The mean follow-up is 40 months (6–95). There was one perioperative death unrelated to the spinal instrumentation. There were no neurologic injuries and there has been no hardware infection to date. There were two dural tears, three superficial wound infections, and three minor wound breakdowns successfully treated. Hardware complications included three cervical plate/screw extrusions reoperated, one cervical plate fracture reoperated, one posterior cervical screw backout not reoperated, one case of broken pedicle screws not reoperated, one vertebral body failure not reoperated, and one posterior rod case reoperated for excessive rod length and protrusion. The overall complication rate attributable to placement of spinal instrumentation was 10/299 (3%) with a reoperation rate of 2%. The arthrodesis rate was 298/299 (99%).

Conclusion

The complication rate for using spinal instrumentation can be less than previously reported. Lessons learned and discussed should reduce the rate even more. Spinal instrumentation is a safe and useful adjunct to fusion in treating degenerative, traumatic, infectious, and neoplastic diseases of the spine.     

Prevention of the crankshaft phenomenon with anterior spinal epiphysiodesis in surgical treatment of severe scoliosis of the younger patient

Summary The aim of this study was to determine whether an anterior approach to the spine with a fusion of the growth centers of the anterior column of the spine, simultaneous by with a posterior fusion and instrumentation of the spine, in young patients with severe scoliosis who have considerable remaining growth, leads to prevention of the crankshaft phenomenon. Twelve patients who have had anterior fusion of the spine associated with posterior fusion and instrumentation of the spine were studied. In 10 of them, growth progression was demonstrated by modification of the Risser sign; for these patients no important progression of the spinal deformity was noted. One patient had no progression of the Risser sign and no progression of spinal deformity. One patient had progression of spinal deformity due to the disruption of the sacral anchorage of instrumentation. We think that this procedure leads to the prevention of the crankshaft phenomenon, and we recommend this procedure in young patients with severe scoliosis and considerable remaining growth. It must include all intervertebral levels of the rigid segment of the curve.     

Neurologic return versus cross-sectional canal area in incomplete thoracolumbar spinal cord injuries

Twenty-four patients with incomplete spinal cord injuries secondary to burst fractures of the thoracolumbar spine were reviewed an average of 26 months after their injury. No patient had had a specific attempt to decompress neural elements but the majority had posterior instrumentation and fusion for spine realignment and stabilization. The amount of neurologic recovery in each patient was compared to the final area of the spinal canal as determined by CT scan. It was concluded that there was no correlation between neurologic improvement and the amount of spinal canal encroachment. In addition, posterior instrumentation to realign the spine will usually restore canal patency to greater than 50% of normal.     

Mechanical principle and clinical application of the combined spinal rod-plate and transpedicular screws fixation system

Twenty-one patients with unstable burst fractures of the lower thoracic and lumbar spine were treated with a combined spinal rod-plate and transpedicular screws (CSRP-TPS) fixation system. This system is a new device for disorders of the lower thoracic and lumbar spine. In treatment of spinal fractures, it provided three-column axial distraction and stabilized the injured vertebra in a lordotic position-this maximized the reduction and indirectly achieved a neurologic decompression by ligamentotaxis. This "indirect" neurologic decompression was more successful in cases treated early after injury as the spinal canal area (measured by pre- and postoperative CT) increased 35% in cases treated within one week after injury; 25% in cases treated 7-14 days after injury; and there was little improvement in cases treated more than two weeks following injury. All patients had a minimum follow-up of 12 months. There were no infections, iatrogenic neurologic deficits or instrumentation failures. The CSRP-TPS system gave more improved results over conventional Harrington and segmental spinal instrumentation systems and only required fixation and fusion of three vertebral levels.     

Instrumentation surgery for tumor of the spine

Spinal instrumentation surgery has come into wide use recently, especially for tumor of the spine. It is very effective for fixing the spine for relieving the patient from pain. But the decision about the indication of instrumentation surgery for tumor of the spine must be made carefully. In cases of double malignant tumors including spinal tumor, it is hard to decide how to treat tumor of the spine. We report a case of 78-year-old male with multiple myeloma of the cervical spine and cancer of the prostate. The patient had been in good health until one year previously, when he started to complain of nuchal pain. He became bedridden with loss of voluntary control of the right upper extremity for the last two months. Then he was admitted to our hospital and radiological examination was carried out. It revealed tumor of the cervical spine and it seemed to be bone metastasis. Further examination revealed that the patient was suffering from multiple myeloma and cancer of the prostate. The tumor of the spine was diagnosed as either multiple myeloma or metastasis of cancer of the prostate. Spinal instrumentation surgery using Luque-rod was carried out as one of the comprehensive treatment plans for double malignant tumors. The instrumentation surgery was effective for fixing the spine and improving the patient's quality of life. In operative procedures, intraoperative spinal cord monitoring was carried out. Intraoperative spinal cord monitoring was indispensable for preventing spinal cord injury. The tumor of the spine was diagnosed as multiple myeloma by pathological examination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spinal implants and radiation therapy: the effect of various configurations of titanium implant systems in a single-level vertebral metastasis model

BACKGROUND: The combination of surgery and radiation therapy is a common clinical practice in the treatment of spinal tumors. Although it is known that metallic implants disturb radiation therapy beams, it is not known what kind of dose distributions appear with spinal irradiation in the presence of a spinal implant. The aim of the present study was to investigate the effect of various spinal implant constructs on the dose of radiation delivered to the spinal canal in a single-level metastasis model. METHODS: We performed four spinal implant reconstructions on standard sawbones spine models: posterior instrumentation without anterior column reconstruction, posterior instrumentation with anterior column reconstruction with use of a titanium cage, anterior instrumentation with anterior column reconstruction with use of a titanium cage, and anterior instrumentation with anterior column reconstruction with use of chest tubes filled with bone cement. Irradiation with two different radiation therapy units (a cobalt-60 teletherapy unit and a linear accelerator) was performed twice for each model in a posterior-to-anterior direction, and thermoluminescent dosimeters were used to measure the dose changes in the anterior, middle, and posterior portions of the spinal canal. RESULTS: Compared with the sawbones-only model, the posterior instrumentation reconstructions resulted in a 5% to 7% decrease in the radiation dose delivered to the spinal canal with both radiation therapy units, whereas the anterior instrumentation reconstructions resulted in a 1% decrease in the dose delivered with the linear accelerator unit and a < or = 2% increase in the dose delivered with the cobalt-60 teletherapy unit. When thermoluminescent dosimeters in the middle of the spinal canal were evaluated individually, anterior instrumentation with anterior column reconstruction with use of bone cement-filled chest tubes resulted in a 5.5% increase in the radiation dose delivered with the cobalt-60 teletherapy unit, whereas all of the other instrumentation models resulted in a <1% disturbance in the radiation dose delivered with both radiation therapy units. CONCLUSIONS: The posterior instrumentation systems did not result in the delivery of an increased dose of radiation to the spinal cord, suggesting that current radiation therapy regimens may be performed without additional harm. The anterior instrumentation systems also appeared to be relatively safe when irradiation was performed with the linear accelerator unit. However, when irradiation was performed with use of the cobalt-60 teletherapy unit, there was an increase in the dose of radiation delivered to the spinal canal in the presence of the anterior instrumentation systems, particularly the anterior column reconstruction with use of bone cement-filled chest tubes. These dose-perturbation characteristics might be important to consider during the calculation of radiation therapy protocols for patients who are going to receive high doses or recurrent treatments that would reach the tolerance limits of the spinal cord.     

钉棒及钩棒系统治疗胸腰椎多节段脊柱骨折

目的评价钉棒及钩棒系统治疗胸腰椎多节段脊柱骨折的临床疗效。方法23例多节段胸腰椎骨折患者，后路切开复位，选择性椎管减压．钉棒或钩棒系统内固定及后外侧植骨融合进行手术治疗。其中相邻多节段型13例，非相邻多节段型8例，混合型2例。结果全组病例平均随访14个月，未发现内固定物松动、断离，无继发性脊柱后凸畸形加重。椎体高度由术前平均48．4％恢复至术后平均92．4%。2例完全性及11例不完全性脊髓损伤者．脊髓神经功能获改善。结论在椎管进行充分减压的基础上．钉棒及钩棒系统能有效复位椎体骨折，重建脊柱稳定性，是多节段胸腰椎不稳定性骨折合并脊髓神经损伤后路手术的理想选择。