Efficacy of Titanium Mesh Cages for Anterior Column Reconstruction after Thoracolumbar Corpectomy

STUDY DESIGN

This retrospective study was conducted to determine the safety and efficacy of titanium cage reconstruction and anterior plating after thoracolumbar corpectomy.

PURPOSE

To study the clinical and radiological outcome of anterior column reconstruction after thoracolumbar corpectomy.

OVERVIEW OF LITERATURE

Anterior column reconstruction aims to optimize neural decompression with adequate stabilization.

METHODS

A series of 16 patients underwent reconstruction after thoracolumbar corpectomy to treat injury due to trauma (n=10), tuberculosis (n=3), and tumor (n=3). The average duration of follow-up was 18 months (range, 8-58 months). The degree of kyphosis, construct height, and the subsidence of the cage in relation to the vertebral endplates were measured. The approach was thoracoabdominal in 10 cases and retroperitoneal in 6 cases.

RESULTS

Four patients were neurologically intact with Frankel grade E on admission, and all remained intact postoperatively. Of the 6 patients with Frankel grade D, all fully recovered full motor and sensory functions. Of the 6 patients with Frankel grade C, three improved one grade and the other three improved two grades. The mean height of the vertebra before surgery was 41 mm and the mean construct height immediately after surgery and at follow-up was 47 mm and 44 mm, respectively. Solid fusion was observed in all patients. The sagittal alignment of the fractured segment was restored immediately after surgery as a significant decrease in the local kyphotic angle.

CONCLUSIONS

Anterior instrumentation is an effective and safe treatment for thoracolumbar instability with satisfactory clinical and radiological outcomes.

Neurologic recovery according to the spinal fracture patterns by Denis classification

PURPOSE

Although Denis classification is considered as one of most clinically useful schemes for the evaluation of spinal fracture, there is little documentation on the relationship between fracture pattern and the neurologic recovery. The purpose is to evaluate the correlation between the fracture patterns according to Denis classification and neurologic recovery.

MATERIALS AND METHODS

The 38 patients (26 men and 12 women) in this series had an average follow-up of 47.1 months, and they were all managed surgically. Denis classification had been used prospectively to determine the fracture morphology. Frankel Scale and American Spinal Injury Association Spinal Cord Injury Assessment Form [American Spinal Injury Association (ASIA) score] were obtained before surgery, after surgery and at the final follow-up.

RESULTS

The common injuries making neurologic deterioration were burst fracture and fracture-dislocation. The degree of neurologic deficits seen first and at the final follow-up was more severe in fracture-dislocation than burst fracture. The neurologic recovery was not different between burst fracture and fracture-dislocation, assessed by Frankel grading and ASIA scoring system. The neurologic recovery evaluated by ASIA score was not different between the lumbar and thoracic spinal fracture. The neurologic recovery assessed by Frankel grade was greater in the lumbar spinal fractures in than the thoracic spinal fractures.

CONCLUSION

The severity of initial and the final follow-up neurologic deficits were correlated with the fracture patterns according to Denis classification, but the neurologic recovery was not correlated.

Clinical results of posterior stabilization without decompression for thoracolumbar burst fractures: is decompression necessary?

The purpose of this study is to investigate the clinical outcome of posterior stabilization without decompression for thoracolumbar burst fractures. Thirty-one consecutive cases of thoracolumbar fractures involving T11-L2 stabilized by a pedicle screw system were reviewed. Neither reduction of the height of a fractured body nor any decompression procedure was added during surgery. Twenty-two patients had incomplete paraplegia; one patient had complete paraplegia. Neurological recovery and remodeling of the spinal canal were evaluated. Neurological status was evaluated at the time of injury, just before and after surgery, and at final follow-up. The degree of spinal canal compromise was assessed using axial CT scan images. The duration of follow-up averaged 39.6 months. The mean spinal canal compromise at the time of injury was 41.6%, and no significant correlation was observed between the degree of canal compromise and the severity of the neurological deficit. Within 2-3 weeks, spinal canal remodeling had started in all patients whose spinal canal compromise was more than 30%, and canal compromise had decreased significantly 3-4 weeks after injury. Seventeen of 22 patients with incomplete paraplegia had already shown partial neurological recovery even before surgery. At the final follow-up, all patients with incomplete paraplegia had improved by at least one modified Frankel grade. This study suggests that the effect of decompressing thoracolumbar fractures with neurological deficits remains unclear and questions the need to operate simply to remove retropulsed bone fragments. Posterior stabilization without decompression should constitute appropriate surgical treatment for these fractures.

Posterior transpedicular decompression for thoracolumbar burst fractures

OBJECTIVES

To demonstrate the feasibility of spinal canal decompression through the posterior transpedicular approach in patients with thoracolumbar burst fractures.

METHODS

We present 25 consecutive patients (19 men and 6 women; mean age 36 years; age range, 24-48 years) with incomplete neurological deficits (ASIA B and C) resulting from thoracolumbar burst fractures treated by posterior transpedicular spinal canal decompression and posterior segmental instrumented fusion. Canal compromise at presentation was 51.7 +/- 11.2%.

RESULTS

The mean surgical time was 122 minutes (range, 108-122 minutes), and the mean blood loss was 528 +/- 123 ml. Canal compromise improved to 15.3 +/- 7.8%. At a mean followup of 14 months (range, 6-18 months), fourteen patients improved to ASIA D and were able to walk with an orthosis; seven improved to ASIA C, and four had no improvement (ASIA B). Seven ASIA B and all ASIA C patients had immediate postoperative neurological improvement to ASIA C and ASIA D; two ASIA B patients improved to ASIA C within six weeks after the operation. Anterior decompression was necessary in two (8%) ASIA B patients who did not improve after the initial operation; these patients, subsequently improved to ASIA C. There were no intraoperative complications. Superficial wound infections occurred in two patients and were treated with wound care and antibiotics; deep infection occurred in one patient and was treated with debridement and antibiotics.

CONCLUSION

Posterior transpedicular spinal canal decompression and instrumentation is a reasonable alternative technique to anterior decompression procedures and circumferential fusion, providing for satisfactory canal decompression and neurological improvement.

Comparison of anterolateral and posterior approaches in the management of thoracolumbar burst fractures

Object

The authors undertook a retrospective cohort study of patients with T11–L2 thoracolumbar burst fractures who underwent decompression and the placement of instrumentation via the anterolateral or posterior approach.

Methods

There were 63 thoracolumbar burst fractures in 45 male and 18 female patients. The instrumentation was placed posteriorly in 25 patients and anterolaterally in 38. The mean follow-up duration after discharge from the hospital was 1.8 years (range 6 months–8 years).

The mean preoperative Frankel scores in the anterolateral and posterior groups were 3.7 ± 1.1 and 3.5 ± 1.4, respectively (p = 0.4155). Preoperative angular deformity in the anterolateral and posterior groups measured 11.9 ± 9.7 and 4.1 ± 7.1°, respectively (p = 0.0007). Postoperatively, angular deformity had been corrected to 2.0 ± 7.9 and 3.4 ± 7.5° in both groups, respectively (p = 0.565). The follow-up Frankel scores had improved to 4.2 ± 0.8 and 4.0 ± 1.4 (p = 0.461). At the latest follow-up examination, angular deformity had progressed to 4.5 ± 9.3° in the anterolateral group and to 9.8 ± 9.4° in the posterior group (p = 0.024).

Although surgeons’ fees were significantly (p = 0.0024) higher for patients who underwent anterolateral procedures ($27,940 ± 4390) than for those who underwent posterior surgery ($18,270 ± 6980), there was no intergroup difference in total cost of hospitalization.

Conclusions

Rigid guidelines for the selection of anterior or posterior approaches are lacking. Evaluation of the authors’ results and those of others shows that angular deformity is more successfully corrected and maintained when the anterior approach is used.

Anterior stabilization of three-column thoracolumbar spinal trauma

Object

The purpose of this study was to evaluate the results obtained in patients who underwent anterior stabilization for three-column thoracolumbar fractures.

Methods

The authors retrospectively reviewed available clinical and radiographic data (1997–2006) to classify three-column thoracolumbar fractures according to the Association for the Study of Internal Fixation (AO) system, neurological status, spinal canal compromise, pre- and postoperative segmental angulation, and arthrodesis rate.

The mean computed tomography–measured preoperative spinal canal compromise was 48.3% (range 8–92%), and the mean vertebral body height loss was 39.4%. The mean preoperative kyphotic deformity of 14.9° improved to 4.6° at the final follow-up examination. Although this angulation had increased a mean of 1.8° during the follow-up period, the extent of correction was still significant compared with the preoperative angulation (p < 0.01). There were no cases of vascular complication or neurological deterioration.

Conclusions

Contemporary anterior spinal reconstruction techniques can allow certain types of unstable three-column thoracolumbar fractures to be treated via an anterior approach alone. Compared with traditional posterior approaches, the anterior route spares lumbar motion segments and obviates the need for harvesting of the iliac crest.

Thoracic spine fractures

Thoracic spine fractures have unique characteristics, and should be managed with specific criteria that are different from those used for thoracolumbar injuries. Fracture-dislocation injuries require high-energy injury, and should always be suspected in polytrauma patients with rib cage, sternum, cardiac, or pulmonary injuries. Although treatment is individualized, multisegmental posterior fixation sometimes combined with anterior decompression, is most commonly used. The authors review the current literature on this topic, and present their opinion on the management of such injuries.

Surgical technique and results of endoscopic anterior spinal canal decompression

OBJECT

Decompression of the spinal canal in the management of thoracolumbar trauma is controversial, but many authors have advocated decompression in patients with severe canal compromise and neurological deficits. Anterior decompression, corpectomy, and fusion have been shown to be more reliable for spinal canal reconstruction than posterior procedures; however, traditional anterior-access procedures, thoracotomy, and thoracoabdominal approaches are associated with significant complications. Endoscopy-guided spinal access avoids causing these morbidities, but it has not been shown to yield equivalent results in spinal canal clearance. This study was conducted to demonstrate the effectiveness of endoscopic spinal canal decompression and reconstruction quantitatively by using pre- and postoperative computerized tomography (CT) scanning.

METHODS

Thirty patients with thoracolumbar canal compromise underwent endoscopic anterior spinal canal decompression, interbody reconstruction, and stabilization for fractures (27 cases), and tumor, infection, and severe degenerative disc disease (one case each). The mean follow-up period was 42 months (range 24 months-6 years). Neurological examinations, Frankel grades, radiological studies, and intraoperative findings were prospectively collected. Spinal canal clearance quantified on pre- and postoperative CT scans improved from 55 to 110%. A total of 25% of patients with complete paraplegia and 65% of those with incomplete neurological deficit improved neurologically. The complication rate was 16.7% and included one reintubation, two pleural effusions, one intercostal neuralgia, and one persistent lesion of the sympathetic chain.

CONCLUSIONS

The authors describe the endoscopic technique of anterior spinal canal decompression in the thoracolumbar spine. The morbidities associated with an open procedure were avoided, and excellent spinal canal clearance was accomplished as was associated neurological improvement.

Transpedicular decompression and pedicle subtraction osteotomy (eggshell procedure): a retrospective review of 59 patients

STUDY DESIGN

Outcomes of transpedicular decompression and/or osteotomy were analyzed retrospectively.

OBJECTIVES

To determine the effectiveness of decompression and correction, fusion stability, procedural safety, neurologic outcome, complication rates, and overall patient outcomes.

SUMMARY OF BACKGROUND INFORMATION

The "eggshell" procedure is reserved for complex reconstructive problems in the treatment of acute trauma, deformity, tumor, or infection. The technique encompasses a range of procedures from simple transpedicular decompression and posterior fusion to more complex procedures, including transpedicular vertebrectomy and strut-grafting or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. These procedures are completed through a single posterior midline incision, with anterior spinal canal decompression a transpedicular approach, accompanied by a posterior or posterolateral fusion and internal fixation.

METHODS

From 1990 to 1998, 59 "eggshell" procedures were performed for 37 deformity cases and 22 tumor or infection cases. Forty-two patients had a minimum 2-year follow-up, averaging 4.5 +/- 2.5 years. Thirty-six patients were available for patient interview, physical examination, and radiographic analysis. Outcome data were collected using SF-36 and SRS instruments.

RESULTS

No patients worsened neurologically, and all incomplete spinal cord injuries improved. All patients achieved solid fusion radiographically. Correction with osteotomy averaged 26 degrees. Systemic complication rates were low with a pulmonary complication rate of 5%. Blood loss averaged 2342 mL. Overall patient outcomes were below population norms, but patient satisfaction was very high.

CONCLUSION

Overall, the results suggest that the "eggshell" procedure is a reliable and safe technique to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach.

Endoscopic approaches to metastatic thoracic disease

Traditional approaches to thoracic metastases and spinal cord compression have been well worked out and validated in the literature. Anterior decompression is clearly superior to laminectomy; vertebrectomy and reconstruction are indicated for sagittal collapse, instability, and pain; and surgical decompression is necessary in cases of bony impingement. The role of endoscopic and minimally invasive techniques in treatment of metastatic disease is evolving. Dr. Lieberman advocates the use of thoracoscopic anterior approaches as the principal application in these patients, whereas Dr. McLain has found that endoscopic assistance has vastly improved his results with posterolateral decompression. The two authors weigh the relative advantages and disadvantages of these approaches for the selected patient with metastatic thoracic disease.

New method for intraoperative determination of proper screw insertion or screw malposition

OBJECT

Inadequate imaging techniques may lead to misjudgment of screw positioning when applying transpedicular instrumentation; this can create potential risks of major vessel and nerve damage. In this article the authors present a new method to determine screw malpositioning intraoperatively.

METHODS

The authors retrospectively evaluated pre- and postoperative plain radiographs of 97 spinal segments in which screws had been placed in 41 patients suffering from thoracolumbar injury who had previously undergone transpedicular screw fixation. They developed a new mathematical equation with which they determine the distance ratios of two screw tips in the same segment by comparing the distance between the pedicles on preoperative radiographs with those on postoperative radiographs. Subsequently, the results are compared with postoperative computerized tomography findings to determine which screws are in the correct position and which are penetrating the medial or lateral cortex of the pedicle. It was found that the ratio range of correctly placed screw tips was 46 +/- 10% (mean +/- standard deviation) in the thoracic region and 60 +/- 9% in the lumbar region (ranges 43-50% and 57-63%, respectively, 95% confidence intervals). Higher ratios (higher percentages) than these values indicated extreme closeness of screw tips and therefore medial malpositioning. Lower ratios (lower percentages) indicated lateral malpositioning.

CONCLUSIONS

This proposed method may provide intraoperative determination of correct screw positioning or malpositioning. This method allows surgeons to replace the malpositioned screw, and, consequently, early resolution of neurovascular injuries is made possible. Additionally, repositioning of the screw correctly will avoid rigidity failure of the fixation device.

Pathogenesis and pharmacological strategies for mitigating secondary damage in acute spinal cord injury

OBJECTIVE

Experimental models and clinical observations of acute spinal cord injury (SCI) support the concepts of primary and secondary injury, in which the initial mechanical insult is succeeded by a series of deleterious events that promote progressive tissue damage and ischemia. Whereas the primary injury is fated by the circumstances of the trauma, the outcome of the secondary injury may be amenable to therapeutic modulation. This article reviews the pathogenetic determinants of these two phases of injury and summarizes the pharmacological manipulations that may restore neurological function after SCI.

METHODS

Experimental models of SCI and their inherent limitations in simulating human SCI are surveyed. The pathogenesis of primary and secondary injury, as well as the theoretical bases of neurological recovery, are examined in detail. The effects of glucocorticoids, lazeroids, gangliosides, opiate antagonists, calcium channel blockers, glutamate receptor antagonists, antioxidants, free radical scavengers, and other pharmacological agents in both animal models and human trials are summarized. Practical limitations to inducing neural regeneration are also addressed.

RESULTS

The molecular events that mediate the pathogenesis of SCI are logical targets for pharmacological manipulation and include glutamate accumulation, aberrant calcium fluxes, free radical formation, lipid peroxidation, and generation of arachidonic acid metabolites. Enhancement of neural regeneration and plasticity comprise other possible strategies.

CONCLUSION

Pharmacological agents must be given within a narrow window of opportunity to be effective. Although many therapeutic agents show potential promise in animal models, only methylprednisolone has been shown in large, randomized, double-blinded human studies to enhance the functional recovery of neural elements after acute SCI. Future therapy is likely to involve various combinations of these agents.

Endoscopically assisted decompression for metastatic thoracic neoplasms

STUDY DESIGN

The author describes a technique for complete vertebrectomy and anterior decompression followed by a formal anterior column reconstruction, using readily available endoscopic instruments. This procedure is indicated in patients with radioresistant metastasis of the thoracic spine, particularly those involving the upper thoracic segments where a thoracotomy is difficult and causes a high rate of morbidity. This is also a suitable technique for patients with pulmonary disease who cannot tolerate a standard thoracotomy.

OBJECTIVES

To demonstrate the feasibility and potential benefits of endoscopically controlled decompression through an extrapleural, posterolateral approach.

SUMMARY OF BACKGROUND DATA

Posterolateral decompression of the thoracic spine offers potential advantages in comparison with traditional anterior-posterior procedures combining thoracotomy and posterior instrumentation, including decreased operative time, decreased morbidity, and reduced hospital stay. Results of previous studies have not demonstrated the same benefit for posterolateral decompression as for anterior vertebrectomy and decompression. Drawbacks to the traditional posterolateral decompressions have included poor visualization of the spinal cord and anterior tumor, poor access to tumor on the side contralateral to the approach, and the need to manipulate the spinal cord to completely remove adjacent tumor and tumor adherent to the dura.

METHODS

Surgical indications, rationale, and technique are provided, and initial clinical results are described.

RESULTS

Transpedicular decompression using endoscopy is described in five patients. The mean operative time for the combined procedure was 7.25 hours, with a mean blood loss of 1800 mL. Neurologic recovery and maintenance were excellent. Inpatient days averaged 7.5, and intensive care days averaged 2. One patient died of disease 8 months after surgery, and four were living, with disease, 3-24 months after surgery.

CONCLUSIONS

Endoscopically assisted decompression can reduce morbidity, hospital stay, and treatment costs while matching the efficacy of traditional combined procedures. Endoscopy provides a readily available and easily applied tool that dramatically improves the surgeon's vision, providing light, magnification, and a direct view of remote structures.

Early management of war missile spine and spinal cord injuries: experience with 21 cases

Between 1991 and 1994, 21 patients with war missile injuries of the spine and spinal cord were treated; there were 17 men and four women, with a mean age 30.7 years; 52.4 per cent were civilians. The wounds were caused by shells (54.6 per cent) and bullets (45.4 per cent). The thoracic and lumbar spines were most commonly injured, and the injuries were frequently associated with lesions of other organs (47.6 per cent). There was extensive initial neurological deficit (tetraplegia, paraplegia) in 47.6 per cent of cases in whom there was no postoperative neurological recovery. All patients were treated operatively and associated injuries of other organs received priority management. A decompressive laminectomy was performed in 80.9 per cent of patients. Penetrating injuries of the dura were recorded in 61.9 per cent, while the spinal cord was injured in 28.5 per cent of patients. The dural defect was reconstructed in these patients. There was a low incidence of postoperative complications (14.5 per cent) which emphasizes the importance of early surgery.

Indirect spinal canal decompression in burst fractures treated with pedicle screw instrumentation

STUDY DESIGN

Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator.

OBJECTIVES

Assessment of the efficacy of "indirect" spinal canal decompression in a large series of burst fractures.

SUMMARY OF BACKGROUND DATA

Up to 50% of burst fractures cause neurologic impairment. Reduction and posterior instrumentation is the most common surgical treatment. This also reduces spinal canal encroachment by indirect decompression. No consensus exists as to the consistency and adequacy of such indirect decompression.

METHODS

Spinal canal areas were measured on preoperative and postoperative computed tomography scans. The degree of encroachment was compared with clinical and radiographic variables for possible correlation.

RESULTS

Spinal canal encroachment was more severe among patients with neurologic deficits than among the neurologically intact. Postoperatively, mean encroachment was reduced from 35% to 12% at T12, from 37% to 17% at L1, and from 52% to 35% at L2. Loss (and postoperative restoration) of anterior vertebral height correlated best with the degree of canal encroachment (and its reduction), especially in Denis Type A burst fractures. In Denis Type B fractures, canal compromise usually was less severe and fragment reduction better in patients older than 40 years of age than in younger patients.

CONCLUSIONS

Indirect decompression in burst fractures averages about half of the preexisting encroachment. Results are usually better at T12 and L1 than at L2. Additional or secondary decompression is rarely indicated if these fractures are treated early and by experienced surgeons. Burst Type B fractures in patients older versus younger than 40 years of age differ in many respects.

Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes

The authors retrospectively studied 49 nonparaplegic patients who sustained acute unstable thoracolumbar burst fractures. All patients underwent surgical treatment and were followed for an average of 27 months. All but one patient achieved solid radiographic fusion. Three treatment groups were studied: the first group of 16 patients underwent anterior decompression and fusion with instrumentation; the second group of 27 patients underwent posterior decompression and fusion; and the third group of six patients had combined anterior-posterior surgery. Prior to surgical intervention, these groups were compared and found to be similar in age, gender, level of injury, percentage of canal compromise, neurological function, and kyphosis. Patients treated with posterior surgery had a statistically significant diminution in operative time and blood loss and number of units transfused. There were no significant intergroup differences when considering postoperative kyphotic correction, neurological function, pain assessment, or the ability to return to work. Posterior surgery was found to be as effective as anterior or anterior-posterior surgery when treating unstable thoracolumbar burst fractures. Posterior surgery, however, takes the least time, causes the least blood loss, and is the least expensive of the three procedures.

Transpedicular decompression and stabilization of burst fractures of the lumbar spine

Twenty-seven consecutive patients with neurological impairment due to burst fractures of the lumbar spine were operated upon, via the postero-lateral route, over a 38-month-period. Transpedicular fixation devices [posterior segmental fixator (PSF) or variable screw placement system (VSP)] were applied in all cases, in order to achieve short-segment fusion of the fractured spinal segment. Return to useful motor power or neurological normality (median follow-up: 18.7 months) occurred in 22 cases (81% of the whole series), with this outcome resulting in all but one of the cases with preoperative incomplete neurological deficit. Postoperative encroachment of the spinal canal, degree of kyphotic deformity, and reduction of the vertebral height showed statistically significant differences compared with the corresponding preoperative values.