Segmental spinal instrumentation of the lumbar spine

Obtaining an arthrodesis of the lumbar spine has always been a problem, especially in the presence of severe disease. The understanding of the segmental character of the lesions and the application of sound orthopedic principles toward low-back spine pathology has led the way to improving arthrodesis with rigid internal fixation. For about eight years, segmental spinal instrumentation has been used in 352 cases to "stabilize" the spine. Many modifications have taken place and knowledge of the biomechanics of abnormal spine has increased through designs of new methods for different disorders. Fixation of low back, when indicated, should be rigid. The rectangular or rhomboid-shaped rod, bent to conform to the lamina cephalad and caudad, and fixed segmentally, proves to be the most rigid. It is contoured to maintain lordosis, sometimes in distraction, sometimes in compression. Fixation is not a substitute for correction of bony deformity or a good surgical arthrodesis. The objective is to maintain correction and promote prompt bony fusion.     

Posterior transpedicular Zielke instrumentation of the lumbar spine

Thirty-three patients treated by posterior transpedicular Zielke instrumentation of the lumbar spine were followed 1.1-2.7 years postoperatively. The average age of the patients was 64 years. The transpedicular technique allowed excellent fixation in patients with poor bone stock secondary to osteoporosis and extensive laminectomy defects. In particular, it allowed distraction and realignment of asymmetrically collapsed foramina with relief of pedicular kinking, correction of lateral deformity, and correction of reduced and fixed listhetic segments. Complications included one broken rod in the immediate postoperative interval while in the hospital. There was no late breakage of rods. The technique of transpedicular fixation with the ability to selectively distract or compress individual segments prevented any further collapse or displacement and allowed correction of areas of scoliotic collapse with relief of root entrapment. A normal lordosis was maintained as indicated by preoperative and postoperative measurements.     

Percutaneous instrumentation of the thoracic and lumbar spine

The development of percutaneous instrumentation systems has been a significant milestone in the ability of surgeons to perform complex spinal procedures through minimally invasive approaches. These systems rely on cannulated screws or portal systems and using intraoperative imaging to allow accurate placement of the spinal implants without a full traditional exposure of the spine. This article reviews the operative concepts and techniques used to place percutaneous instrumentation in the thoracolumbar spine.     

Luque instrumentation in degenerative conditions of the lumbar spine

The authors report on the experience obtained in using L-rods and sublaminar wires in obtaining lower lumbar fusions of three or more levels in degenerative diseases of the lumbar spine. A successful fusion was obtained in 86% of the patients. The technique, while offering a satisfactory method of fusion, does violate the spinal canal with sublaminar wires with potential for neurologic injury. Specifically, the passage of sacral wires should be avoided.     

Anatomic considerations for anterior instrumentation of the lumbar spine.

One hundred seventy lumbar vertebrae from L1-L4 were used to quantitatively evaluate the lumbar vertebral body and examine the relationship of the maximum posterior angles of screw placement to the spinal canal. Anatomic evaluation included dimensions of the vertebral body. Three entrance points on the lateral aspect of the vertebral body for screw insertion and an additional point 3 mm from the posterolateral corner of the spinal canal were defined and marked. The maximum posterior screw angles were determined as the angles between the line connecting the entrance point with the additional point and the coronal plane. Results showed that vertebral body dimensions increased from L1-L4. The average vertebral body depth, width, and height were approximately 26 mm, 36 mm, and 22 mm at L1, and 30 mm, 44 mm, and 23 mm at L4, respectively. The spinal canal may be penetrated if the screws are directed posteriorly 2 degrees-5 degrees at L1 - L2 and 9 degrees - 14 degrees at L3-L4 starting at the junction between the pedicle and vertebral body, 22 degrees - 32 degrees at L1-L4 from the level of 10 mm anterior to the junction, and 43 degrees -50 degrees from the level of 20 mm anterior to the junction. Therefore, mid-body screws should be directed perpendicular to the lateral plane of the vertebral body. For a more anteriorly placed screw, slightly posterior angulation is recommended.     

Biomechanical evaluation of a posterior non-fusion instrumentation of the lumbar spine

Purpose  

Numerous posterior non-fusion systems have been developed within the past decade to resolve the disadvantages of rigid instrumentations and preserve spinal motion. The aim of this study was to investigate the effect of a new dynamic stabilization device, to measure the screw anchorage after flexibility testing and compare it with data reported in the literature.     

The low lumbar spine below Cotrel-Dubousset instrumentation: long-term findings

STUDY DESIGN: Retrospective review of long instrumented fusions down to the low lumbar spine for the treatment of adolescent idiopathic scoliosis. OBJECTIVES: To evaluate whether the use of instrumentation systems that preserve the sagittal profile could reduce the incidence of early degenerative changes. SUMMARY OF BACKGROUND DATA: Long fusions and distractive Harrington instrumentation in the surgical treatment of adolescent idiopathic scoliosis (AIS) are known to produce pain and degenerative changes in the free lumbar segments. Reports on the use of Cotrel-Dubousett instrumentation (CDI) confirm that the instrumentation maintains physiologic lumbar lordosis, but the evolution of the spine below the fusion is not addressed. METHOD: Thirty-five patients with AIS and CDI were studied. Their spines were fused to L3 or lower, and they had a minimum follow-up of 10 years. Radiologic measurements were recorded from frontal and lateral radiographs. At the time of last examination, lateral flexion-extension dynamic radiographs and magnetic resonance imaging evaluated the health of the disks below the fusion. Clinical outcome was assessed with the Scoliosis Research Society instrument. A control group consisting of 35 peers without scoliosis served as a reference for the outcome questionnaire. RESULTS: Surgery kept the sagittal profile in a physiologic range. All but two patients were satisfied with the results of surgery. There were no differences between patients and control group insofar as pain, self-image, general function, and daily activity were concerned. Eleven patients showed instability signs in dynamic radiographs and more than half of patients showed incipient degeneration on magnetic resonance images. These findings are similar to those found in the general population, according to the literature, and could evidence normal aging processes. CONCLUSIONS: Cotrel-Dubousset instrumentation maintains the physiologic sagittal contour. Although there are some degenerative changes in magnetic resonance images and dynamic radiographs, the quality of life and daily activities of the patients after surgery are similar to those of a normal population of the same age.     

Cotrel-Dubousset instrumentation in the treatment of unstable thoracic and lumbar spine fractures

The use of computed tomography and developments in spinal biomechanics have led to a better understanding of vertebral fractures. The disappointing results achieved with conservative treatment have led to an increasing popularity of surgical treatment in the last 15 years. The results of 20 unstable thoracic or lumbar spine fractures treated surgically with Cotrel-Dubousset instrumentation at the First Clinic of Orthopaedics and Traumatology of the Ankara Social Security Hospital between December 1988 and June 1991 were evaluated in this study. The mean follow-up was 31.9 months. The mean sagittal index angle was 23.7° ± 6.8° preoperatively and was corrected by 67.1 ± 29.9%, and the thoracolumbar junction angle was brought within physiological limits in 65% of the cases. Postoperatively, the neurological status improved in 15% of the patients and remained unchanged in the rest. It was concluded that the Cotrel-Dubousset instrumentation established vertebral stability in unstable vertebral fractures by forming a rigid frame and restored physiological thoracic and lumbar postural contours due to its highly corrective effect in the sagittal plane.     

Anterior transpedicular instrumentation of the lumbar spine: an anatomical study.

Lumbar burst fractures or massive tumorous destruction of the lumbar spine generally require a combined anterior-posterior surgical approach for adequate decompression and stabilization. Anatomical studies in 10 adult cadavers with 100 pedicle screw placements from a single strictly anterior approach showed that this new method represents a safe and promising way for stable lumbar spine instrumentation, avoiding the risks of a bilateral approach. The technique provides a stability comparable with bilateral instrumentation. Exact knowledge of the geometry of the corresponding vertebral bodies and the spinal canal by computed tomography scanning is a prerequisite for this surgical technique. First clinical applications using this technique reconfirm the experiences of the anatomical study.     

Treatment of unstable thoracolumbar and lumbar spine injuries using Cotrel-Dubousset instrumentation

STUDY DESIGN: In this prospective study, the results of treating unstable thoracolumbar and lumbar injuries with Cotrel-Dubousset instrumentation were investigated. OBJECTIVE: To determine the pain and work status of the patients, to evaluate neurologic status, and to assess the efficacy of instrumentation in the short term. SUMMARY OF BACKGROUND DATA: Short-segment pedicle screw construct is the method of choice for reduction and stabilization of unstable thoracolumbar spinal injuries. Many investigators have recently reported a high rate of instrument failure. In this study, the use of segmental transpedicular fixation two levels above the kyphosis decreased instrument failure and sagittal collapse. METHODS: Thirty patients, who had unstable thoracolumbar and lumbar spinal injuries, underwent application from a posterior approach of Cotrel-Dubousset instrumentation two levels above and one below at the thoracolumbar junction and short segment fixation in the lumbar area. Radiologic parameters were evaluated before and after surgery. RESULTS: The mean follow up was 31 months (range, 25-49) months. There were statistically significant differences between the pre- and postoperative values in all radiologic parameters. Neurologic status improved in 70% of the patients, with a mean Frankel grade of 1.3 grades. CONCLUSIONS: Cotrel-Dubousset instrumentation provided spinal stability in unstable injuries, forming a rigid construct and restoring physiologic thoracolumbar and lumbar postural contours because of its highly corrective effect in the sagittal profile with no loss of correction.     

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。     

Anterior instrumentation for the treatment of pyogenic vertebral osteomyelitis of thoracic and lumbar spine

Anterior radical debridement and bone grafting is popular in the treatment of pyogenic infection of the spine, but there remains great concern of placing instrumentation in the presence of infection because of the potentiality of infection recurrence after surgery. The objective of this study was to prospectively evaluate the efficacy and safety of anterior instrumentation in patients who underwent simultaneous anterior debridement and autogenous bone grafting for the treatment of pyogenic vertebral osteomyelitis. The series consisted of 22 consecutive patients who were treated with anterior debridement, interbody fusion with autogenous bone grafting and anterior instrumentation for pyogenic vertebral osteomyelitis of thoracic and lumbar spine. The patients were prospectively followed up for a minimum of 3 years (average 46.1 months; range 36–74 months). Data were obtained for assessing clinically the neurological function and pain and radiologically the spinal alignment and fusion progress as well as recurrence of the infection. All the patients experienced complete or significant relief of back pain with rapid improvement of neurological function. Kyphosis was improved with an average correction rate of 93.1% (range 84–100%). Solid fusion and healing of the infection was achieved in all the patients without any evidence of recurrent or residual infection. The study shows that combined with perioperative antibiotic regimen, anterior instrumentation is effective and safe in the treatment of pyogenic vertebral osteomyelitis of thoracic and lumbar spine directly following radical debridement and autogenous bone grafting.     

Clinical efficacy of pedicle instrumentation and posterolateral fusion in the symptomatic degenerative lumbar spine

Summary Eighty-five patients with degenerative lumbar spine disease and radiologic evidence of instability, all older than 50 years (mean age 63.4 years), underwent transpedicular lumbar CD-spondylodesis and posterolateral fusion between 1987 and 1992; 30 of them (mean age 60.8 years) had posterior lumbar interbody fusion (PLIF) additionally. The patients were followed up for a mean period of 32 months. Of these patients, 86% improved with respect to their pain symptoms, but only 46% showed a good to excellent overall result. Patients with fair and poor outcomes had had significantly more operations on the lumbar spine (P0<0.001), had a greater extent of preoperative lumbar kyphosis (P0<0.05), had a larger preopcrative motor weakness (P0<0.05), and had less vertebral slips (P0<0.01) than patients with good to excellent outcomes. Patients treated with transpedicular spondylodesis plus PLIF did not make any better progress than those with transpedicular fusion alone. By the 6-month followup a significant difference in the clinical outcome was already apparent (P0<0.001), making an improvement of a then fair or poor result unlikely.     

Dwyer instrumentation of the spine

The evolution of the Dwyer procedure during the past 10 years has enabled us to better define the indications and contraindications for the procedure. The role of the Dwyer procedure in the treatment of thoracolumbar or lumbar curves in both the adolescent and the adult has been found to be significant. When combined with Harrington rod instrumentation it can be used for either paralytic curves, curves associated with pelvic obliquity, or curves in which posterior elements are absent.     

Single stage corpectomy and instrumentation in the treatment of pathological fractures in the lumbar spine

Purpose  

Corpectomy and implantation of titanium cages is standard in pathological fracture treatment but additional single ventral instrumentation remains controversial with regard to rotational stability.     

Anterior spine fusion using Zielke instrumentation for adult thoracolumbar and lumbar scoliosis

Analysis of adult patients undergoing anterior spine fusions with Zielke instrumentation between January 1983 and November 1986 was performed. Objectives were to review results of surgical treatment and identify factors affecting results. Charts, 3 foot standing anteroposterior and lateral and supine maximal side bending radiographs were reviewed. Subjective data were obtained by telephone. There were 26 patients, average age 41 years. Average radiographic follow-up was 48 months. Indications were pain and curve progression. Average correction was 63% of the instrumented curve. Average change of lordosis was 8 degrees and kyphosis was 6 degrees. Apical vertebral rotation corrected an average of 37%. Complications were: eight hardware failures, one deep infection, and two psychiatric events. The high-risk groups: curves greater than 60 degrees, patients older than 50 years of age, and rigid curves.     

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.