Anterior Column Reconstruction Research Articles

Management of unstable thoracolumbar spinal injuries by posterior short segment spinal fixation: reply to comments by Singh

Dear Editor, We thank the correspondent for his comments and for providing us a chance to clarify a few important points. Our main objective was to review the outcome of the treatment of unstable thoracolumbar spinal fractures by short-segment spinal fixation. Instrumentation failure is a known complication of this type of treatment. We mentioned this as an adverse outcome in our series [1]. We concur with the observation that posterior instrumentation is weaker in compression and is liable to fatigue and fail in the presence of a coexisting weak anterior column. We, however, believe that instrumentation failure is multifactorial and factors other than implant design and fracture characteristic contribute to it [2]. Although some authors have claimed better results using fixation two levels above and below the injured segment in severe vertebral comminution [3], we do not have any experience with this technique. Our paper is primarily meant to assess and report the results of short-segment fixation only. We however believe that anterior column reconstruction would be a better choice in such cases to the extent of obviating the need for transpedicular grafting. In essence we have tried to report the results of short-segment posterior instrumentation in totality and reflect the requirement of a more comprehensive classification, which would narrow down the indications of this instrumentation, thereby ensuring better results. We are currently working on developing a classification (unpublished data) by combining the system of MacAfee [4] and McCormack [5] in an attempt to pre-operatively segregate the patients for treatment by anterior or posterior instrumentation.

Comment on Butt et al.: Management of unstable thoracolumbar spinal injuries by posterior short segment spinal fixation

Dear Editor, We have read the article [1] with great interest, and we want to applaud the authors’ efforts to simplify a rather controversial topic. We differ from the authors regarding the management of unstable thoracolumbar spinal injuries and would like to add a few salient points. Short segment fixation has been shown to have higher rates of pedicle screw failure, which is thought to result from cyclic loading combined with poor anterior column support [3]. In our opinion this may be the cause of the high rates of hardware failure in the authors’ series. As also rightly mentioned by the authors in their Discussion, posterior instrumentation alone cannot reconstitute anterior column support and is therefore somewhat weaker in compression than anterior instrumentation [2]. Some surgeons suggest using fixation two levels above and below the injured segment in severely comminuted vertebrae, particularly if bone quality is poor or in areas of higher stress concentration such as the thoracolumbar junction, taking care of mobile lumbar segments [4]. This has been clearly mentioned by the authors too, but not taken care of. Transpedicular bone grafting has been suggested as a means of improving the anterior column support, though the results are not encouraging [3]. In the case of vertebral body height loss >50% or extensive comminution, pedicle screws are placed two levels above and below the fractured vertebrae. If there is <50% height loss, an attempt at short segment stabilisation is undertaken, with the recommendation that short transpedicular screws should be inserted at the level of the fracture [5]. Finally, we would like to draw the authors’ attention to the “load-sharing classification” of McCormack et al., where a score is assigned to the degree of vertebral body comminution, fracture fragment apposition and kyphosis. Patients with a score >6 would be better treated with addition of anterior column reconstruction [6].

THORACOSCOPIC VERTEBRAL BODY REPLACEMENT WITH AN EXPANDABLE CAGE AFTER VENTRAL SPINAL CANAL DECOMPRESSION

Minimally invasive thoracic anterior surgery using a thoracoscopic approach has evolved to include spinal biopsy, debridement, discectomy, decompressive corpectomy, interbody fusions, and internal fixations. Minimal access techniques can potentially decrease surgical access morbidity and also reduce the time required for recovery and healing. The thoracoscopic approach for decompression, stabilization, and anterior vertebral reconstruction of thoracolumbar fractures is described. In this article and video, we discuss patient selection, surgical positioning, port placement, thoracic level localization, exposure and removal of fractured vertebral bodies, anterior vertebral column reconstruction using an expandable cage, instrumentation, and postoperative management. The potential advantages of using a minimally invasive thoracoscopic approach include direct trajectory to anterior spine pathology, minimal tissue and rib retraction, and decreased postoperative pain and length of hospital stay. The associated disadvantages include the steep learning curve for the surgeon, the need to operate with two-dimensional visual information and long instruments, and the requirement that one have an experienced surgical assistant. Minimally invasive surgery using a thoracoscopic approach for vertebral body replacement with an expandable cage can be performed safely. Expandable cages facilitate the vertebral body reconstruction via minimal access surgery.

P165. Clinical Research of Thoracoscopy-Assisted Mini-open Surgery for Anterior Column Reconstruction of Thoracic Spine Tuberculosis

BACKGROUND CONTEXT: Anterior debridement and autograft on the basis of anti-tuberculosis medicine are effective treatments to complex thoracic tuberculosis. Nevertheless, the traditional anterior open surgery have a lot of disavantages such as large trauma, slow recovery,many complications during the perioperative period.

The use of an expandable cage for corpectomy reconstruction of vertebral body tumors through a posterior extracavitary approach: a multicenter consecutive case series of prospectively followed patients

Background context Posterior decompressions in the form of laminectomies for vertebral body tumors have poor outcomes. Surgical management typically requires anterior decompression and reconstruction; however, these procedures can be associated with significant morbidity and mortality. Purpose To evaluate the feasibility of anterior spinal column reconstruction using an expandable cage through a posterior approach. Study design/setting Multicenter consecutive case series of 21 prospectively followed patients. Patient sample Twenty-one patients with vertebral body tumors treated with anterior and posterior resection and reconstruction from a single posterior approach were followed prospectively. Outcome measures Pre- and postoperative neurologic status, number of levels instrumented and fused, length of surgery, length of stay after surgery, and complications related directly or indirectly to surgery were analyzed. In addition, pre- and postoperative radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans were evaluated for involvement of the vertebral body and associated posterior elements. Particular attention was paid to the presence of either unilateral or bilateral pedicle and/or middle column involvement. Methods Patients were placed in a prone position on a rotating radiolucent table. Corpectomy was performed from an extracavitary approach, and anterior column reconstruction was completed with an expandable cage. The posterior tension band and spinal fusion was completed with segmental pedicle screw fixation and performed through the same posterior exposure. No patient required a separate anterior procedure. Results Patients' average age was 60.3 years (range, 17–78); there were 12 women and 9 men. Eighteen underwent single-level corpectomies (11 thoracic and 7 lumbar), and 3 underwent two-level corpectomies (T4–T5, T11–T12, and T12–L1). Average estimated blood loss (EBL) and length of surgery per level were 1,360 cc (range, 200–2,500) and 5.3 hours (range, 2.7–8.6), respectively. Average postoperative stay was 4.7 days. Nine patients had at least one partial motor grade improvement. One patient had postoperative left lower extremity weakness after surgical decompression and reconstruction secondary to iatrogenic nerve root traction but remained ambulatory. No chest tubes or postoperative bracing was required. At the most recent follow-up, six patients were alive at an average of 16.1 months (range, 3–33). For the 15 patients who died, the average life span after surgery was 6.8 months (range, 1–16). In addition to the iatrogenic nerve root injury, one cage required repositioning on postoperative Day 2 and one cage demonstrated radiographic evidence of settling but did not require surgical intervention; there were no deep venous thromboses (DVTs), pneumothoraces, pneumonias, ileus, or other complications, with a total complication rate of 14.3%. Conclusions This is the largest study that specifically examines the use of an expandable cage through a posterior extracavitary approach for reconstruction after vertebral body tumor resection. The use of an expandable cage combined with an extracavitary approach is feasible and allows the surgeon to address both the anterior and posterior columns through a single incision. Although technically challenging, both one- and two-level corpectomies in the thoracic and/or lumbar spine can be performed with this technique. Furthermore, insertion of the expandable cage in the collapsed position and then expansion in situ after implantation allowed for all lumbar reconstructions to be completed without sacrificing any of the lumbar nerve roots. Our 14.3% complication rate is similar to those reported in anterior-alone and circumferential spinal procedures.

CT-based classification of long spinal allograft fusion.

Anterior column reconstruction of the thoracolumbar spine by structural allograft has an increased potential for biological fusion when compared to synthetic reconstructive options. Estimation of cortical union and trabecular in-growth is, however, traditionally based on plain radiography, a technique lacking in sensitivity. A new assessment method of bony union using high-speed spiral CT imaging is proposed which reflects the gradually increasing biological stability of the construct. Grade I (complete fusion) implies cortical union of the allograft and central trabecular continuity. Grade II (partial fusion) implies cortical union of the structural allograft with partial trabecular incorporation. Grade III (unipolar pseudarthrosis) denotes superior or inferior cortical non-union of the central allograft with partial trabecular discontinuity centrally and Grade IV (bipolar pseudarthrosis) suggests both superior and inferior cortical non-union with a complete lack of central trabecular continuity. Twenty-five patients underwent anterior spinal reconstruction for a single level burst fracture between T4 and L5. At a minimum of two years follow up the subjects underwent high-speed spiral CT scanning through the reconstructed region of the thoracolumbar spine. The classification showed satisfactory interobserver (kappa score = 0.91) and intraobserver (kappa score = 0.95) reliability. The use of high-speed CT imaging in the assessment of structural allograft union may allow a more accurate assessment of union. The classification system presented allows a reproducible categorization of allograft incorporation with implications for treatment.

A Comparative Biomechanical Analysis of Spinal Instability and Instrumentation of the Cervicothoracic Junction

Stabilization of the cervicothoracic junction is challenging but commonly required in patients with traumatic, neoplastic, congenital, and postlaminectomy conditions. Although extensive research has been performed on stabilization of the cervical spine, there remains a paucity of published data on instrumentation at the cervicothoracic junction. Using 2-column, 3-column, and corpectomy instability models, a biomechanical analysis was performed on the effects of increasing the number of posterior segmental fixation points and/or anterior column reconstruction at the cervicothoracic junction. Multidirectional flexibility testing was performed utilizing a 6-degree-of-freedom spine simulator and 7 fresh-frozen human cadaveric spines (occiput-T6). After intact spine analysis, each specimen was destabilized and reconstructed as follows: (1) C7/T1 2-column injury with posterior instrumentation; (2) C7/T1 3-column injury with posterior instrumentation; (3) C7/T1 3-column injury with anterior interbody cage/plate and posterior instrumentation; and (4) C7/T1 3-column injury plus C7 corpectomy with anterior cage/plate and posterior instrumentation. All reconstruction groups were tested with posterior instrumentation (screws connected by dual-diameter rods) from C5-T1, C5-T2, and C5-T3. For 2-column injuries, there were no statistically significant differences in flexibility (P>0.05), although there was a trend toward reduced flexibility with increasing levels of thoracic fixation. For 3-column injuries, posterior fixation alone resulted in excessive flexibility in flexion/extension even with instrumentation to T3 (P<0.05). With the addition of anterior column instrumentation, there were no observed differences in flexion/extension and lateral bending. For axial rotation, instrumentation to T1 alone demonstrated increased motion relative to the intact spine (P<0.05). The 3-column injury with corpectomy model demonstrated similar flexibility properties to the 3-column injury model. With 3-column instability posterior segmental fixation alone from C5-T3 was inadequate, and the addition of anterior instrumentation restored flexibility to the intact condition. There was a strong trend toward reduced flexibility with increasing levels of thoracic fixation in all instability models.

Clinical research of thoracoscopy-assisted mini-open surgery for anterior column reconstruction of thoracic spine tuberculosis

To evaluate the clinic effects of thoracoscopy-assisted mini-open surgery for anterior column reconstruction of thoracic spine tuberculosis. Sixty patients with thoracic spine tuberculosis, involving segments T4 to T12, with a kyphotic angle of 29.2 degrees (18-42 degrees), 38 males and 22 females, aged 47.4 (19-68), with large paraspinal abscess in 50 cases, pleurisy in 17, and dural compression in 42 cases shown by imaging examination, underwent thoracoscopic-assisted mini-open surgery, including radical debridement and anterior spinal reconstruction. According to Frankel's grade, the preoperative neurological function was judged as: Grade A in 1 case, Grade B in 4, Grade C in 6, Grade D in 19, and Grade E in 30. The patients were followed up for 3.6 years. The outcomes were evaluated retrospectively. The operation was accomplished successfully in all 60 patients. The average operative time was 230 min (180-320 min), the average blood loss during operation was 570 ml (350-1200 ml), the mean drainage duration was 3.6 d (3-5 d). Complications occurred in 18 patients (30%). 30 patients showed neurological improvement from 1 to 3 Grades at the last follow-up. The average correction rate of kyphotic angle was 36.6%, and no obvious correction loss was detected during the follow-up. No patient showed recurrence of tuberculosis. Thoracoscopy-assisted mini-open surgery provides a simple, safe, effective, and practical technology with minimal invasiveness for the treatment of thoracic spine tuberculosis.

Surgical treatment for unstable low-grade isthmic spondylolisthesis in adults: a prospective controlled study of posterior instrumented fusion compared with combined anterior-posterior fusion

The surgical treatment for low-grade isthmic spondylolisthesis in adults with intractable lumbar pain is usually spinal fusion. It has been postulated that anterior column reconstruction may be relatively advantageous in those patients with unstable slips. To compare the early and medium term treatment efficacy of two common fusion techniques in isthmic spondylolisthesis. Prospective controlled trial comparing single-level posterior-lateral instrumented fusion with combined anterior and posterior-lateral instrumented fusion in sequential matched cohorts of patients with radiographically unstable isthmic spondylolisthesis. Primary outcome measure of success was an Oswestry Disability Index (ODI)<or=20. Secondary outcome measures included patient determined minimum-acceptable outcome on four questionnaires: pain intensity (visual analog scale), ODI, medication intake, and work status. Radiographic outcome of fusion was determined by radiographic union and motion on flexion/extension X-rays. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for primary outcome of success for combined fusion compared with posterior fusion. The study was conducted over a 6-year period. The first cohort of 50 consecutive patients was treated with a single-level instrumented posterior-lateral fusion; the second sequential cohort was treated with an anterior interbody fusion and the same posterior operation. Observations were made at baseline, 6 months, 1 year, and 2 years after surgery. Final radiographic assessment was made at 2 years after surgery. Baseline demographic and clinical factors were well-matched in the two cohorts. At 2 years, 46 posterior-only fusion subjects and 47 combined fusion subjects completed the full follow-up regimen. Outcomes were better by all measures at 6 months and 12 months in the anterior-posterior cohort. Comparing the primary outcome measure (ODI outcome<or=20) in the posterior versus the combined groups, success was achieved at 6 months in 11 versus 30 (RR=2.67, 95% CI 1.53, 4.67; p=.0001); at 1 year, 20 versus 34 (RR=1.66, 95% CI 1.14, 2.42; p<.005); and at 2 years, 29 versus 36 subjects (RR=1.21, 95% CI 0.93, 1.59; p=.14). At 6 months, 13 posterior-only and 25 combined group subjects had returned to work (RR 1.88, 95% CI 1.10, 3.21; p=.01). More patients achieved their preoperatively determined minimum-acceptable outcome at each time point. There were three nonunions in the posterior-alone cohort and one in the combined group. Serious complications and reoperations were similar in both groups. Outcomes up to 2 years were superior by clinically important differences after a combined anterior-posterior operation compared with posterior-alone surgery for unstable spondylolisthesis; however, between-group differences attenuated appreciably after 6 months. The apparent clinical and occupational benefits of combined fusion should be considered along with possible increases in minor complications and procedure-related costs.

P108. Anterior Allograft Bone Dowel Treatment of Pyogenic Vertebral Osteomyelitis

BACKGROUND CONTEXT: Pyogenic vertebral osteomyelitis is a rare clinical problem which usually responds to immobilization and intravenous antibiotics. Failure of medical management requires operative treatment consisting of anterior debridement and anterior column reconstruction. Structural iliac crest autograft is currently considered the gold standard but involves morbidity associated with the harvest.

10:46 OPA 1. Surgical Treatment for Unstable Low-Grade Isthmic Spondylolisthesis in Adults: A Prospective Controlled Study of Posterior Instrumented Fusion Compared With Combined Anterior-Posterior Fusion

BACKGROUND CONTEXT: The surgical treatment for low-grade isthmic spondylolisthesis in adults with intractable lumbar pain is usually spinal fusion. It has been postulated that anterior column reconstruction may be relatively advantageous in those patients with unstable slips.

Anterior Column Reconstruction Using Titanium Ring Cages in Severe Vertebral Osteomyelitis

Background and Purpose: The use of instrumentation in spinal infections is still a controversial issue. The aim of the present study was to evaluate the efficiency of titanium cages in the surgical treatment of severe vertebral osteomyelitis (synonym spondylodiscitis) concerning eradication of the infection as well as biomechanical aspects. Materials and Methods: The peri- and postoperative data of 43 consecutive patients with vertebral osteomyelitis who underwent single-stage posterior stabilization, anterior debridement including decompression, and anterior column reconstruction using modular titanium ring cages filled with autologous bone were analyzed retrospectively. In 29 cases, a clinical and radiological follow-up of on average 2.5 years (median 2.2 years) was available. To assess the course of spinal alignment, a detailed radiometric analysis was performed. Results: The time of symptoms prior to surgery averaged 4.6 months. Preoperatively, 37% of the patients showed neurologic compromise with partial or complete recovery in 88% after surgery. In 25 patients (58%), a germ was isolated with Staphylococcus aureus being the most frequent pathogen (44%). Except for one patient with anterior revision and exchange of the cage for persistent infection, primary eradication of the infection was accomplished in all patients. At follow-up, all infections were eradicated, and all cages appeared radiographically fused. The present loss of correction in the sagittal plane amounted 1.5° at the affected segment(s) reconstructed by cage interposition and 4.4° at posterior fusion levels. Conclusion: Single-stage posterior instrumentation and fusion combined with anterior debridement and anterior column reconstruction using modular titanium ring cages represent a safe and efficient strategy in cases of severe vertebral osteomyelitis necessitating surgery. The use of titanium cages guarantees longterm maintenance of correction without increased risk of persistent or recurrent infection.

Palliative Spinal Reconstruction Using Cervical Pedicle Screws for Metastatic Lesions of the Spine

A retrospective study. To evaluate clinical outcomes of palliative spinal reconstruction using cervical pedicle screws in metastatic spine tumors. No study to date has investigated the effectiveness of cervical pedicle screw fixation in metastatic lesions of the spine. A total of 32 patients with metastatic spine tumors who underwent reconstructive surgery using cervical pedicle screws were reviewed. Four patients presented upper cervical lesions and 28 patients had subaxial lesions. All patients had intractable pain, 29 presented myelopathy, and 18 patients were nonambulatory. Combined anterior column reconstruction was considered in cases of life expectancy more than 2 years and anterior spinal cord compression that could not be solved by posterior decompression and kyphosis correction. Posterior fixation alone was performed in 25 patients, and posterior fixation combined with anterior column reconstruction was performed in 7 patients. The average postoperative survival period was 12.2 months. Neck pain was improved in all cases. Twenty-four (83%) of the 29 patients with spinal cord lesions presented neurologic improvement. Of 18 patients who were not ambulatory, 16 patients (89%) became ambulatory. Pain relief, neurologic function, and spinal stability were maintained throughout the survival period in 30 of 32 patients (94%). Spinal reconstruction using cervical pedicle screws improved spinal stability, pain, and neurologic function. These improvements were maintained throughout the survival period in 94% of the patients. Anterior column reconstruction could be avoided in 78% of the patients in spite of damaged anterior column.

SPINAL IMPLANTS AND RADIATION THERAPY

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 ≤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.

Spinal Implants and Radiation Therapy

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. 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. 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. 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.

Single-Stage Thoracolumbar Vertebrectomy With Circumferential Reconstruction And Arthrodesis: Surgical Technique And Results In 15 Patients

Circumferential reconstruction and arthrodesis can be necessary after thoracolumbar vertebrectomy. The authors describe a technique for single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis. The surgical results using this technique are reviewed. Fifteen patients ranging from 14 to 75 years of age underwent single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis. The vertebrectomy was performed through a posterior midline approach. Anterior column reconstruction was performed with expandable or nonexpandable cages. Anterior and posterolateral arthrodeses used autograft. Posterior segmental instrumentation was used in all cases. Fifteen procedures have been performed to date, 4 for tumor and 11 for fracture. The range of treated levels was T4 to L2 (7 thoracic spine and 8 lumbar spine levels). One patient was incomplete preoperatively (Frankel Grade C) and improved to being intact postoperatively (Frankel Grade E), another improved from Frankel Grade C to Frankel Grade D. All other patients were neurologically unchanged postoperatively. Mean operative time was 4.0 hours. Average blood loss was 1100 ml. Average number of levels fused was 5.8 (range 4-9). There were four complications: one delayed transient neurological deficit after deformity correction, one infection, one postoperative myocardial infarction, and one hardware failure. All patients were treated and had a good recovery. The authors present a method for thoracolumbar vertebrectomy, circumferential reconstruction, and arthrodesis performed in a single stage, solely via a posterior approach. This is an alternative to anterior (i.e., thoracoabdominal and retroperitoneal) and lateral (i.e., lateral extracavitary) approaches that can be used for circumferential reconstruction and arthrodesis. Potential advantages and pitfalls are discussed.

Posterior Vertebral Column Resection in Fixed Lumbosacral Deformity

Retrospective study. To report the results and the technique of posterior vertebral column resection (PVCR) in fixed lumbosacral deformity. Fixed lumbosacral deformity has gross imbalance as well as progressive compensatory thoracolumbar deformity because of the absence of a mobile spine caudally. There is no consensus of the surgical treatment of fixed lumbosacral deformity. Fixed lumbosacral deformity can be managed by PVCR, which not only corrects the deformity but also restores the trunk balance by translation of spinal column. Twenty-five consecutive fixed lumbosacral deformity patients subjected to PVCR were reviewed after a minimum follow-up of 2 years. The apical vertebra and the ultimately resected vertebra were below L4 in most cases. Etiologic diagnoses were congenital scoliosis in 6, congenital kyphoscoliosis in 3, post-traumatic kyphosis in 2, and postinfectious kyphosis in 14. The average age at the operation was 38 years (range, 2.5-61 years) with a male:female ratio of 7:18. The indication for PVCR was fixed lumbosacral deformities that could not be brought to a reasonable balance on traction or forced side bending. Before surgery, 12 patients (48%) presented with neurologic compromise and 20 patients (80%) presented with intractable back pain. The surgical technique consisted of segmental pedicle screw fixation, decompression of neural structures, and resection of the vertebral column at the apex of the deformity via the posterior route, followed by deformity correction and global fusion. During the resection, all the nerve roots were preserved. Two and one tenth (2.1) vertebrae removed on average (range, 1-5 vertebrae), and 52 in all. The average fusion extent was 4.5 vertebrae (range, 2-8 vertebrae). The anterior column reconstruction was carried out with autogenous bone graft in all patients and additional insertion of titanium mesh in 12. The distal anchor went down to L5 in 4 patients, S1 in 12, and S2 in 9. Preoperative scoliosis of 38 degrees +/- 12 degrees was corrected to 15 degrees +/- 8 degrees (60% correction) at most recent follow-up, and preoperative kyphosis of 35 degrees +/- 25 degrees was corrected to -5 degrees +/- 11 degrees (40 degrees correction). The compensatory coronal curve of 26 degrees was spontaneously corrected to 12 degrees at most recent follow-up. The preoperative thoracic lordosis of -16 degrees was corrected to 4 degrees at most recent follow-up, and the preoperative lumbar kyphosis of 20 degrees was corrected to -17 degrees . Preoperative coronal imbalance of 2.0 cm was improved to 0.9 cm at most recent follow-up, and preoperative sagittal imbalance of 9.3 cm was improved to 4.6 cm. Mean operation time was 280 minutes with a blood loss of 2,810 mL. The preoperative neurologic compromise was improved in all patients, and pain was reduced to less than half of preoperative visual analog analog scale in 17 patients. The following complications were encountered in 5 patients: 2 with transient neurology that spontaneously improved without a sequel within 6 months, 2 with compression fractures at proximal adjacent vertebra, and 1 with pseudarthrosis. PVCR is an effective procedure for the management of fixed lumbosacral deformity. It provides satisfactory correction and improved functional outcomes. However, it is a technically demanding and exhausting procedure with possible risks for complications.

Surgical treatment of metastatic lesion of the spine. A review of 51 consecutive cases operated

Metastatic lesions of the spine have recently become a debated topic in orthopaedics, because more and more patients survive long enough to require surgical treatment. The aim of this study is to review a series of 51 patients affected by metastatic lesions of the spine. Fifty-one patients affected by metastatic lesions of the spine were treated between 1987 and 2000. In 5 cases the cervical spine was involved, in 27 the thoracic and in 19 the lumbar spine. Surgery was planned according to the following labelling factors: type of malignancy, life expectancy, neurological involvement, pain, site of lesion, lesion extension and spine stability. Surgical treatment consisted of: minimally invasive cord decompression in 3 cases, posterior stabilization in 21, posterior stabilization and cord decompression in 13 cases, anterior resection and reconstruction of anterior column associated or not at posterior stabilization in 14 cases. Two patients died due to complications related to surgery. At the last available follow-up of 4 (±2.5) years, 29 patients had excellent results, 16 had good results, 2 fair and 2 poor results. One fair and 1 poor result had recurrence of the metastatic lesions of the spine and needed another operation. We believe that surgical treatment of metastatic lesion of the spine has a positive cost/benefit ratio for the patient's condition; in fact most of our patients had improvement of quality of life. The labelling factors of each lesion have to be carefully studied together with the oncologist to decide the correct surgical option because unsatisfactory results could be sometimes related to incorrect evaluation of the evolution of the neoplasm.

Expandable vertebral body replacement in patients with thoracolumbar spine tumors

The objectives of surgical interventions for tumoral lesions of the spine include the establishment and improvement of tumor-related symptoms. Anterior tumor resection followed by reconstruction indicated if surgical treatment allowed a marginal removal of the tumor or could extend the individual survival rate in combination with adjuvant therapy options. Sufficient re-stabilization depends on adequate anterior column reconstruction. The purpose of this retrospective study was to present our experiences and results after anterior tumor resection followed by reconstruction with the expandable vertebral body replacement device (VBR, Ulrich, Germany) based on clinical application over 4 degrees years. We carried out an anterior tumor resection followed by reconstruction using an anterior extendable device in 32 patients with different spine tumors between 1996 and 2000. A retrospective evaluation was executed considering the patients medical records and radiological findings. Additionally, a clinical and radiological investigation of still living postoperative patients was carried out. The mean surgical time of all evaluated patients was 317.2 min. The average blood loss was 1,272.5 ml. According to the Tokuhashi score, patients with a postoperative survival time of at least 12 months demonstrated a score value > or = 9 points. According to our evaluated patients group metastatic lesions of the spine represented the largest group (78.1%). The average survival rate of this group amounted to 18.4 months postoperatively. Considering primary tumors the average survival rate at the time of last re-examination amounted to 34.8 months postoperatively. Preoperative neurological pathologies were present in 12 patients (Frankel stage C-D). During the postoperative monitoring period 58.3% of the patients demonstrated an improvement in initial neurological findings. There were no intraoperative complications or perioperative deaths. Implant dislocations were not observed. On account of the underlying, the anterior tumor resection with supplementary instrumentation represented a sufficient procedure in spinal tumor surgery. Adjuvant therapy can influence the postoperative survival period positively in addition to the surgical procedure. Following anterior tumor resection, extendable vertebral body replacements like the VBR device provide immediate spine stability by excellent defect adaptation. With regard to their intraoperative flexibility, expandable cages are more advantageous in contrast to non-expandable implants or bone grafts.

Operative Therapie der unspezifischen und spezifischen Spondylodiszitis

The aim of this study was to evaluate the clinical and radiological results of surgical treatment of thoracic and lumbar vertebral osteomyelitis by means of one-stage extrafocal posterior stabilisation, anterior debridement, and anterior column reconstruction. A retrospective analysis of the peri- and postoperative parameters of 62 patients with a clinical and radiographic follow-up of 2.6 years that were available for 46 patients was performed. In 42 cases, the anterior column was restored with structural bone grafts, in 20 patients, expandable titanium cages filled with morsellised autologous bone and antibiotic collagen sponges were used. To assess the course of spinal alignment a radiometric analysis was undertaken. Furthermore, the Roland-Morris score (RMS) was applied to evaluate the back pain-related disability. The diagnosis was made no earlier than 2.7 months after the first symptoms. Preoperatively, 40 % of the patients presented with neurological impairment, of these 76 % improved after surgery. Staphylococcus aureus was the most common pathogen isolated (32 %), Mycobacterium tuberculosis was found in 11 % of the patients. Except for one patient with revision for persistent infection and consecutive failure of the bone graft, primary eradication of the infection was achieved in all cases. At follow-up, bony fusion was radiographically observed in all patients. When using cages, the segmental loss of correction was significantly lower than when using bone grafts (1.0 vs. 4.1 degrees ). At follow-up the RMS averaged 6.6. One-stage extrafocal posterior stabilisation combined with anterior debridement and anterior column reconstruction with bone grafts or titanium cages is a safe and effective strategy for patients with vertebral osteomyelitis in need of surgery. Titanium cages have proven to be biomechanically advantageous, especially in cases of extensive destruction and are not associated with higher rates of persistence or recurrence of infection compared to autologous bone grafts.