Surgical technique and results of endoscopic anterior spinal canal decompression

Outcomes of Anterior Decompression and Anterior Instrumentation in Thoracolumbar Burst Fractures-A Prospective Observational Study With Mid-Term Follow-up

OBJECTIVE

To analyze the functional, neurological, and radiological outcomes after anterior surgery in thoracolumbar burst fractures.

DESIGN

Prospective observational study.

SETTING

Tertiary care hospital.

PATIENTS

Thirty-six patients with thoracolumbar burst fractures (T11-L2).

INTERVENTION

Anterior decompression, anterior column reconstruction with mesh cage, and instrumented stabilization.

OUTCOME

Functional (Visual Analog Score, Oswestry Disability Index, and Spinal Cord Independence Measure), neurological (ASIA Impairment Scale), and radiological (kyphosis, anterior vertebral height loss, canal encroachment %) parameters.

RESULTS

Patients were prospectively followed for a mean duration of 5.9 ± 3.2 years (2.4-10 years). Statistically significant improvement was noted in functional outcomes from preop values (P-value < 0.001). 29 patients (80.5%) had improvement in neurology after surgery at the final follow-up with a positive correlation with % change in canal encroachment (r = 0.64, P -0.018). The mean preoperative kyphosis of 29.1 ± 11.9 degrees got corrected to 9.4 ± 3.8 degrees in immediate postop and 15.7 ± 11.8 at the final follow-up(P < 0.001). Preoperative mean canal encroachment of 58.5 ± 15.7% was reduced to 6.5 ± 3.2% postoperatively (P < 0.001). Two patients developed neurological complications (subacute progressive ascending myelopathy), and 5 patients developed pulmonary complications. No pseudarthrosis, implant loosening, or cage migration was noted in any patient.

CONCLUSION

Anterior surgery performed in 36 patients with thoracolumbar burst fractures in our study showed good outcomes. 80.5% of patients improved in neurology after surgery by at least one ASIA Impairment Scale grade. There was statistically significant improvement noted in radiological outcome (Kyphosis and Canal encroachment %) and functional outcome (Visual Analog Score, Oswestry Disability Index, and Spinal Cord Independence Measure score) after surgery in immediate postop and at the final follow-up. Only 13.8% of patients developed pulmonary complications that were managed successfully with chest drain.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Safety and Efficacy of Single-Stage versus 2-Stage Spinal Fusion via Posterior Instrumentation and Anterior Thoracoscopy: A Retrospective Matched-Pair Cohort Study with 247 Consecutive Patients

OBJECTIVE

Posterior-anterior spondylodesis is often used to stabilize the spine in various pathologies. The anterior procedure is often performed via thoracoscopy. It is unclear whether the anterior procedure should be performed immediately after posterior instrumentation or after the patient has convalesced. This retrospective study compared perioperative safety and morbidity in 1-stage versus 2-stage posterior-anterior fusion surgery with a thoracoscopic anterior approach.

METHODS

All consecutive patients who underwent surgery for posterior-anterior spinal stabilization from 2006 to 2013 were included. American Society of Anesthesiologists score, preoperative and postoperative laboratory values, operation duration, blood loss, intensive care unit stay, pain, postoperative hospital stay, perioperative complications, and preoperative and postoperative Eastern Cooperative Oncology Group and Frankel scores were assessed. A subset of the cohort was selected by propensity score matching to eliminate possible selection bias.

RESULTS

There were 247 patients who underwent 1-stage (n = 104) or 2-stage (n = 143) stabilization with thoracoscopic fusion. Spinal pathologies were fracture, malignancy, pyogenic spondylodiscitis, degenerative spinal disorders, and failed previous surgery. One-stage and 2-stage procedures were similar in terms of preoperative, surgical, and postoperative variables, including complication rates, except that the 1-stage procedure was associated with greater pain 2 days after surgery and shorter hospital stay. The propensity score-matched cohort of 64 pairs yielded similar results with only 1-stage patients showing elevated visual analog scale score on postoperative day 2 (3.8 vs. 2.4, P = 0.043).

CONCLUSIONS

One-stage stabilization was as safe as 2-stage stabilization and associated with shorter hospitalization. Greater pain after the 1-stage procedure, which resolved 30 days after surgery, reflects the fact that 2-stage patients already had pain relief when they underwent thoracoscopy.

Surgical Incision and Approach in Thoracolumbar Extreme Lateral Interbody Fusion Surgery: An Anatomic Study of the Diaphragmatic Attachments

STUDY DESIGN

Cadaveric study.

OBJECTIVE

To provide anatomical basis for deciding the surgical approach and skin incision in thoracolumbar extreme lateral interbody fusion (XLIF) by delineating the attachment points of diaphragm.

SUMMARY OF BACKGROUND DATA

Although the general anatomy of the thoracic diaphragm is well described, the specific attachment points of diaphragm concerned with the XLIF approach is yet to be elaborated.

METHODS

Dissections were performed on 21 cases of formalin fixed specimens (12 males, 9 females, a total of 42 sets of data). Special attention was paid to the attachment points of diaphragm on both sides at the midaxillary line (MAL point) and the vertebral level parallel to the MAL point (VL-MAL). The attachment points of diaphragm on the front and back edge of the spinal column (FES point and BES point) were also described.

RESULTS

The MAL point of diaphragm muscle lied between the inferior edge of the 10th rib and the superior edge of the 12th rib (20 out of 21 on left, 21 out of 21 on right). VL-MAL lied between L1 and L2 vertebrae level (20 out of 21 on left, 18 out of 21 on right). The attachments on both sides of the vertebral column mainly located between the upper edge of T12 vertebrae and L1-L2 disc (38 out of 42).

CONCLUSION

A transthoracic approach should be considered when the target level was above T12 vertebrae, whereas a retroperitoneal approach should be chosen when target level was below L1-L2 disc. If the target level is located between T12 and L1-L2 disc, whether via transthoracic, retropleural, or retroperitoneal approach should be determined according to the conditions of patients and the skill and experience of the surgeon. Incision should be made above the 10th rib for the transthoracic approach and below the 12th rib for the retroperitoneal approach.

LEVEL OF EVIDENCE

4.

Minimal Invasive Circumferential Management of Thoracolumbar Spine Fractures

Introduction. While thoracolumbar fractures are common lesions, no strong consensus is available at the moment. Objectives. The aim of this study was to evaluate the results of a minimal invasive strategy using percutaneous instrumentation and anterior approach in the management of thoracolumbar unstable fractures. Methods. 39 patients were included in this retrospective study. Radiologic evaluation was based on vertebral and regional kyphosis, vertebral body height restoration, and fusion rate. Clinical evaluation was based on Visual Analogic Score (VAS). All evaluations were done preoperatively and at 1-year follow-up. Results. Both vertebral and regional kyphoses were significantly improved on postoperative evaluation (13° and 7° versus −1° and −9°  P < 0.05, resp.) as well as vertebral body height (0.92 versus 1.16, P < 0.05). At 1-year follow-up, mean loss of correction was 1°. A solid fusion was visible in all the cases, and mean VAS was significantly reduced form 8/10 preoperatively to 1/10 at the last follow-up. Conclusion. Management of thoracolumbar fractures using percutaneous osteosynthesis and minimal invasive anterior approach (telescopic vertebral body prosthesis) is a valuable strategy. Results of this strategy offer satisfactory and stable results in time.

Management of thoracolumbar spine trauma: An overview

Thoracolumbar spine fractures are common injuries that can result in significant disability, deformity and neurological deficit. Controversies exist regarding the appropriate radiological investigations, the indications for surgical management and the timing, approach and type of surgery. This review provides an overview of the epidemiology, biomechanical principles, radiological and clinical evaluation, classification and management principles. Literature review of all relevant articles published in PubMed covering thoracolumbar spine fractures with or without neurologic deficit was performed. The search terms used were thoracolumbar, thoracic, lumbar, fracture, trauma and management. All relevant articles and abstracts covering thoracolumbar spine fractures with and without neurologic deficit were reviewed. Biomechanically the thoracolumbar spine is predisposed to a higher incidence of spinal injuries. Computed tomography provides adequate bony detail for assessing spinal stability while magnetic resonance imaging shows injuries to soft tissues (posterior ligamentous complex [PLC]) and neurological structures. Different classification systems exist and the most recent is the AO spine knowledge forum classification of thoracolumbar trauma. Treatment includes both nonoperative and operative methods and selected based on the degree of bony injury, neurological involvement, presence of associated injuries and the integrity of the PLC. Significant advances in imaging have helped in the better understanding of thoracolumbar fractures, including information on canal morphology and injury to soft tissue structures. The ideal classification that is simple, comprehensive and guides management is still elusive. Involvement of three columns, progressive neurological deficit, significant kyphosis and canal compromise with neurological deficit are accepted indications for surgical stabilization through anterior, posterior or combined approaches.

Management of thoracolumbar spine fractures

BACKGROUND CONTEXT

Traumatic fractures of the spine are most common at the thoracolumbar junction and can be a source of great disability.

PURPOSE

To review the most current information regarding the pathophysiology, injury pattern, treatment options, and outcomes.

STUDY DESIGN

Literature review.

METHODS

Relevant articles, textbook chapters, and abstracts covering thoracolumbar spine fractures with and without neurologic deficit from 1960 to the present were reviewed.

RESULTS

The thoracolumbar spine represents a unique system from a skeletal as well as neurological standpoint. The rigid rib-bearing thoracic spine articulates with the more mobile lumbar spine at the thoracolumbar junction (T10 - L2), the site of most fractures. A complete examination includes a careful neurologic examination of both motor and sensory systems. CT scans best describe bony detail while MRI is most efficient at describing soft tissues and neurological structures. The most recent classification system is that of the new Thoracolumbar Injury Classification and Severity Score. The different fracture types include compression fractures, burst fractures - both stable and unstable -, flexion-distraction injuries and fracture dislocations. Their treatment, both operative and non-operative depends on the degree of bony compromise, neurological involvement, and the integrity of the posterior ligamentous complex. Minimally invasive approaches to the care of thoracolumbar injuries have become more popular, thus, the evidence regarding their efficacy is presented. Finally, the treatment of osteoporotic fractures of the thoracolumbar spine is reviewed, including vertebroplasty and kyphoplasty, their risks and controversies, and senile burst fractures, as well.

CONCLUSIONS

Thoracolumbar spine fractures remain a significant source of potential morbidity. Advances in treatment have minimized the invasiveness of our surgery and in certain stable situations, eliminated it all together.

Subphrenic hematoma after thoracoscopic discectomy: description of a very rare adverse event and review of the literature on complications

The authors describe a very rare and previously unreported complication of thoracoscopic discectomy. Endoscopic spine surgery has evolved as a safe and effective treatment, and thoracoscopic discectomy, in particular, provides several advantages over open approaches, although it can be associated with intraoperative or postoperative complications. The most frequently observed adverse events are intercostal neuralgia, retained disc fragments, durotomies, atelectasis, extensive bleeding, and emergency conversion to open thoracotomy for vascular injuries. Even rare complications, such as chylorrhea or brain hemorrhagic infarction, have been reported. Nonetheless, a literature review did not reveal any case of postoperative intraabdominal hematoma following thoracoscopic discectomy. A 43-year-old woman, with no history of hematological or vascular disorders or thoracic surgery, underwent a right-sided thoracoscopic discectomy for T11–12 disc herniation. No apparent surgical technique–related complications were encountered, but intermittently repeated difficulties with single-lung ventilation occurred. The resultant dysventilation allowed partial right lung reexpansion, along with increased abdominal pressure. The latter induced an upward ballooning of the right diaphragm with consequent obstruction of the surgical field of view, requiring constant and continuous pressure applied to the thoracic surface of the diaphragm via a metal fan retractor and thus counteracting the increased abdominal pressure. Postoperatively, a large subdiaphragmatic hematoma originating from a bleeding right inferior phrenic artery was diagnosed and required urgent endovascular occlusion. The patient made an uneventful recovery with conservative treatment. A very rare and previously unreported complication—that is, early subdiaphragmatic hematoma after thoracoscopic discectomy—is described here. The authors submit that conversion to an open approach is safer when persistent anesthesia-related complications are encountered in thoracoscopic discectomy.

[Current status of thoracoscopic surgery for thoracic and lumbar spine. Part 1: general aspects and treatment of fractures]

INTRODUCTION

Thoracoscopic surgery or video-assisted thoracic surgery (VATS) of the thoracic and lumbar spine has greatly evolved since it appeared less than 20 years ago. Nowadays, it is indicated in a large number of processes and injuries. The aim of this article, in its 2 parts, is to review the current status of VATS in treatment of the thoracic and lumbar spine in its entire spectrum.

DEVELOPMENT

After reviewing the current literature, we develop each of the large groups of indications where VATS is used, one by one. This first part contains a description of general thoracoscopic surgical technique including the necessary prerequisites, transdiaphragmatic approach, techniques and instrumentation used in spine reconstruction, as well as a review of treatment and specific techniques in the management of spinal fractures.

CONCLUSIONS

Thoracoscopic surgery is in many cases an alternative to conventional open surgery. The transdiaphragmatic approach has made endoscopic treatment of many thoracolumbar junction processes possible, thus widening the spectrum of therapeutic indications. These include the treatment of fractures and deformities, as well as the reconstruction of injured spinal segments and decompression of the spinal canal in any etiological processes if the lesion placement is favourable to antero-lateral approach. Good clinical results of thoracoscopic surgery are supported by the growing experience reflected in a large number of articles. The degree of complications in thoracoscopic surgery is comparable to open surgery, with benefits in morbidity of the approach and subsequent patient recovery.

Extreme Lateral Interbody Fusion (XLIF) in the Thoracic and Thoracolumbar Spine: Technical Report and Early Outcomes

BACKGROUND

Previous studies have demonstrated the distinct advantages of thoracoscopically assisted spinal fusion compared to traditional open thoracotomy. However, these techniques are limited by a steep learning curve, prolonged operative time, and lack of three-dimensional visualization of the surgical field.

OBJECTIVE

The objective of this study was to describe our initial experience with an adaptation of the extreme lateral interbody fusion (XLIF) technique allowing access to the anterior aspect of the thoracic and thoracolumbar spine with specific reference to (1) early pulmonary complications, (2) non-pulmonary complications, and (3) ability of this technique to successfully achieve spinal decompression and fusion at the operative level.

METHODS

Clinical and radiographic data were reviewed for the entire perioperative period. A total of 18 patients (72% females; mean age, 56.8 years) underwent a thoracic XLIF procedure for spinal pathologies including disc herniation, fracture, tumor, pseudoarthrosis, and proximal junctional kyphosis. A total of 32 levels were treated, with the majority located at the thoracolumbar junction. Twelve of the procedures were done as part of a combined anterior/posterior surgery.

RESULTS

The mean estimated blood loss was 577 ml and the mean length of stay was 12 days. At a mean follow-up of 14 months, all patients except for one (who died of widely metastatic disease) had achieved radiographic evidence of fusion. Two patients developed pulmonary effusions requiring medical intervention. Six patients had seven non-pulmonary complications: incidental durotomy (two), infection (one), instrumentation pullout (one), cardiac arrhythmia (two), and death from metastatic disease (one).

CONCLUSIONS

The XLIF technique can be utilized for access to the anterior column of the thoracic and thoracolumbar spine. The advantages of this minimally invasive technique include avoidance of the need for an access surgeon and for lung deflation during surgery as well as excellent visualization of the spinal pathology.

Outcome after thoracoscopic ventral stabilisation of thoracic and lumbar spine fractures

BACKGROUND AND PURPOSE

Thoracoscopic-assisted ventral stabilisation for thoracolumbar fractures has been shown to be associated with decreased recovery time and less morbidity when compared with open procedures. However, there are a limited number of studies evaluating late clinical and radiological results after thoracoscopic spinal surgery.

METHODS

We performed an analysis of the late outcomes of thoracolumbar fractures after minimally invasive thoracoscopic ventral instrumentation. Between August 2003 and December 2008, 70 patients with thoracolumbar fractures (T5-L2) underwent ventral thoracoscopic stabilisation. Tricortical bone grafts, anterior plating systems (MACS-System), and cage implants were used for stabilisation. Outcomes measured include radiologic images (superior inferior endplate angle), Visual Analogue Scale (VAS), VAS Spine Score, quality of life scores SF-36 and Oswestry Disability Index (ODI).

RESULTS

Forty seven patients (67%, 47 out of 70) were recruited for the follow up evaluation (2.2 ± 1.5 years). Lower VAS Spine scores were calculated in patients with intra- or postoperative complications (44.7 (± 16.7) vs. 65.8 (± 24.5), p=0.0447). There was no difference in outcome between patients treated with bone graft vs. cage implants. Loss of correction was observed in both bone graft and titanium cage groups.

INTERPRETATION

The present study demonstrates diminished long-term quality of life in patients treated with thoracoscopic ventral spine when compared with the outcome of german reference population. In contrast to the other patients, those patients without intra-operative or post-operative complications were associated with improved outcome. The stabilisation method (bone graft versus spinal cage) did not affect the long-term clinical or radiographic results in this series.

[Reconstruction after spinal fractures in the thoracolumbar region]

The morbidity of anterior approaches has significantly influenced the development of therapeutic concepts for the treatment of thoracolumbar spine fractures. Minimally-invasive techniques such as mini-open and endoscopic have enlarged the numbers of anterior reconstruction after spinal fractures in the thoracolumbar region. These minimally-invasive approaches have been facilitated by the development of special implants adapted to the new technique and to the local anatomical requirements.Two multi center studies in Germany (MCSI and II) showed the trend towards minimal invasive procedures and anterior approaches in the German speaking spine centers. Since the first report on thoracoscopic anterior procedures in Germany in 1997 a growing number of spine centers established this method. There is still no evidence based high level literature to substantiate a significant benefit for the patients by anatomical reduction and reconstruction of the anterior spinal column. However, there are some reports on better short outcomes in radiological parameters as well as better clinical results in 5 to 8 year follow-ups.The minimal invasive anterior approach seems to be advantageous for the patients by reducing significantly additive operation morbidity. It has become more important over the last two decades for anterior reconstruction after trauma and posttraumatic malalignment of the thoracolumbar spine.

Anterior approach to the thoracic spine

An anterior approach affords the spine surgeon excellent visualization and access to the anterior thoracic spine, the vertebral bodies, intervertebral disks, spinal canal, and nerve roots. This approach is currently used in the surgical treatment of thoracic disk disease, vertebral osteomyelitis or discitis, fractures and tumors of the vertebral bodies, allowing for proper decompression of neural elements and spine stabilization. Over a 10-year period in a single institution, a total of 142 patients with a mean age of 49.6 years underwent anterior thoracic exposure of the spine. The indication for surgery was trauma fracture in 20 patients, malignancy in 35, degenerative disease in 29 and correction of scoliosis in 58. Surgical approaches were determined based on the location and length of spinal involvement, including cervico-thoracic approach (15) thoracotomic approach (85) video-assisted thoracoscopy (10) and thoracolumbar exposure (32). Mean operative time was 334 min (range from 256 to 410 min). There was no perioperative mortality. Thirty-one patients (21.8%) developed postoperative complications. The anterior approach to the thoracic spine is safe and effective and even the presence of complications can be appropriately managed. An adequate preoperative evaluation stratifying the risk and instituting measures to reduce it, accurate surgical planning and careful surgical technique are key to yielding a good outcome and to reduce the risk of complications.

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, Internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

The second, internet-based multicenter study (MCSII) of the Spine Study Group of the German Association of Trauma Surgery (Deutsche Gesellschaft für Unfallchirurgie) is a representative patient collection of acute traumatic thoracolumbar (T1-L5) injuries. The MCSII results are an update of those obtained with the first multicenter study (MCSI) more than a decade ago. The aim of the study was to assess and bring into focus: the (1) epidemiologic data, (2) surgical and radiological outcome, and (3) 2-year follow-up (FU) results of these injuries. According to the Magerl/AO classification, there were 424 (57.8%) compression fractures (A type), 178 (24.3%) distractions injuries (B type), and 131 (17.9%) rotational injuries (C type). B and C type injuries carried a higher risk for neurological deficits, concomitant injuries, and multiple vertebral fractures. The level of injury was located at the thoracolumbar junction (T11-L2) in 67.0% of the case. 380 (51.8%) patients were operated on by posterior stabilization and instrumentation alone (POSTERIOR), 34 (4.6%) had an anterior procedure (ANTERIOR), and 319 (43.5%) patients were treated with combined posteroanterior surgery (COMBINED). 65% of patients with thoracic (T1-T10) and 57% with lumbar spinal (L3-L5) injuries were treated with a single posterior approach (POSTERIOR). 47% of the patients with thoracolumbar junction (T11-L2) injuries were either operated from posterior or with a combined posterior-anterior surgery (COMBINED) each. Short angular stable implant systems have replaced conventional non-angular stable instrumentation systems to a large extent. The posttraumatic deformity was restored best with COMBINED surgery. T-spine injuries were accompanied by a higher number and more severe neurologic deficits than TL junction or L-spine injuries. At the same time T-spine injuries showed less potential for neurologic recovery especially in paraplegic (Frankel/AISA A) patients. 5% of all patients required revision surgery for perioperative complications. Follow-up data of 558 (76.1%) patients were available and collected during a 30-month period from 1 January 2004 until 31 May 2006. On average, a posterior implant removal was carried out in a total of 382 COMBINED and POSTERIOR patients 12 months after the initial surgery. On average, the rehabilitation process required 3-4 weeks of inpatient treatment, followed by another 4 months of outpatient therapy and was significantly shorter when compared with MCSI in the mid-1990s. From the time of injury until FU, 80 (60.6%) of 132 patients with initial neurological deficits improved at least one grade on the Frankel/ASIA Scale; 8 (1.3%) patients deteriorated. A higher recovery rate was observed for incomplete neurological injuries (73%) than complete neurological injuries (44%). Different surgical approaches did not have a significant influence on the neurologic recovery until FU. Nevertheless, neurological deficits are the most important factors for the functional outcome and prognosis of TL spinal injuries. POSTERIOR patients had a better functional and subjective outcome at FU than COMBINED patients. However, the posttraumatic radiological deformity was best corrected in COMBINED patients and showed significantly less residual kyphotic deformity (biseg GDW -3.8° COMBINED vs. -6.1° POSTERIOR) at FU (p = 0.005). The sagittal spinal alignment was better maintained when using vertebral body replacement implants (cages) in comparison to iliac strut grafts. Additional anterior plate systems did not have a significant influence on the radiological FU results. In conclusion, comprehensive data of a large patient population with acute thoracolumbar spinal injuries has been obtained and analyzed with this prospective internet-based multicenter study. Thus, updated results and the clinical outcome of the current operative treatment strategies in participating German and Austrian trauma centers have been presented. Nevertheless, it was not possible to answer all remaining questions to contradictory findings of the subjective, clinical outcome and corresponding radiological findings between different surgical subgroups. Randomized-controlled long-term investigations seem mandatory and the next step in future clinical research of Spine Study Group of the German Trauma Society.

The biomechanical contribution of varying posterior constructs following anterior thoracolumbar corpectomy and reconstruction

OBJECT

Thoracolumbar corpectomy is a procedure commonly required for the treatment of various pathologies involving the vertebral body. Although the biomechanical stability of anterior reconstruction with plating has been studied, the biomechanical contribution of posterior instrumentation to anterior constructs remains unknown. The purpose of this study was to evaluate biomechanical stability after anterior thoracolumbar corpectomy and reconstruction with varying posterior constructs by measuring bending stiffness for the axes of flexion/extension, lateral bending, and axial rotation.

METHODS

Seven fresh human cadaveric thoracolumbar spine specimens were tested intact and after L-1 corpectomy and strut grafting with 4 different fixation techniques: anterior plating with bilateral, ipsilateral, contralateral, or no posterior pedicle screw fixation. Bending stiffness was measured under pure moments of +/- 5 Nm in flexion/extension, lateral bending, and axial rotation, while maintaining an axial preload of 100 N with a follower load. Results for each configuration were normalized to the intact condition and were compared using ANOVA.

RESULTS

Spinal constructs with anterior-posterior spinal reconstruction and bilateral posterior pedicle screws were significantly stiffer in flexion/extension than intact spines or spines with anterior plating alone. Anterior plating without pedicle screw fixation was no different from the intact spine in flexion/extension and lateral bending. All constructs had reduced stiffness in axial rotation compared with intact spines.

CONCLUSIONS

The addition of bilateral posterior instrumentation provided significantly greater stability at the thoracolumbar junction after total corpectomy than anterior plating and should be considered in cases in which anterior column reconstruction alone may be insufficient. In cases precluding bilateral posterior fixation, unilateral posterior instrumentation may provide some additional stability.

Fracture models in the lumbar sheep spine: a biomechanical investigation

The purpose of this study was to find out if a limited resection of the cranial vertebral body leaving the posterior wall intact is a sufficient model for AO type 3 fractures, or if additional resection of the posterior wall is necessary. In six, fresh-frozen, lumbar sheep spine specimens, the segmental stability was tested in three motion planes in a spine tester. First, the intact specimens were tested. Then, partial resection of the intervertebral disc L3/4 and resection of the cranial vertebral body of L4 was performed, leaving the posterior wall intact. This defect was tested without instrumentation and with a ventral monosegmental interlocking plate mounted. Then, the defect was extended to a total cranial resection, including the posterior wall, and the tests were subsequently repeated. The stability of both types of defects under the different conditions was compared. Without instrumentation, the total cranial resection showed significantly more ROM in flexion/extension and axial rotation than partial cranial resection. With the ventral interlocking plate mounted, the instability in total cranial resection was significantly higher in flexion/extension, with the relative relation even being increased. In axial rotation and lateral bending, the differences were equalized by the mounted plate. From a biomechanical point of view, total cranial resection including the posterior wall should be preferred as a sheep spine fracture model for AO type 3 fractures.

Approach-related lesions of the sympathetic chain in anterior correction and instrumentation of idiopathic scoliosis

During anterior scoliosis instrumentation with a dual-rod system, the vertebrae are dissected anterolaterally. After surgery, some patients report a change in temperature perception and perspiration in the lower extremities. Sympathetic lesions might be an explanation for this. The aim of this clinical study was to investigate sympathetic function after anterior scoliosis instrumentation. A total of 24 female patients with idiopathic scoliosis (mean age at follow-up, 23.8 years) who had undergone anterior instrumentation on average 6.6 years earlier were included. Due to the suspected relevance of the sympathetic L2 ganglion, two groups were created: a T12 group, in which instrumentation down to T12 was carried out (n = 12), and an L3 group, in which instrumentation down to L3 was done (n = 12). Sympathetic function was assessed by measuring skin temperature at the back of the foot, a plantar ninhydrin sweat test and sympathetic skin responses (SSRs) following electrical stimulation. The side on which the surgical approach was carried out was compared with the contralateral, control side. Health-related quality of life was investigated using the Scoliosis Research Society SRS-22 patient questionnaire. In the T12 group, mean temperatures of 29.6 degrees C on the side of the approach versus 29.5 degrees C on the control side were measured (P > 0.05); in the L3 group, the mean temperatures were 33.2 degrees C on the approach side versus 30.5 degrees C on the control side (P = 0.001). A significant difference between the T12 group and the L3 group (P < 0.001) was observed on the approach side, but not on the control side (P = 0.15). The ninhydrin sweat test showed reduced perspiration in 11 of 12 patients in the L3 group on the approach side in comparison with the control side (P = 0.002). In the T12 group, no significant differences were noted between the left and right feet. SSRs differed significantly between the two groups (P = 0.005). They were detected in all nine analyzable patients in the T12 group on both sides. In the L3 group, they were found on the approach side only in 4 of 11 analyzable patients versus 11 patients on the control side. The results of the SRS-22 questionnaire did not show any significant differences between the two groups. In conclusion, anterior scoliosis instrumentation with a dual-rod system including vertebrae down to L3 regularly leads to lesions in the sympathetic trunk. These are detectable with an increase in temperature, reduced perspiration and reduced SSRs. The caudal level of instrumentation (T12 vs. L3) has an impact on the extent of impairment, supporting the suspected importance of the L2 ganglion. The clinical outcome does not seem to be significantly limited by sympathetic trunk lesions.

Blood transfusions after thoracoscopic anterior thoracolumbar vertebrectomy

PURPOSE

Anterior vertebral body reconstruction (AVBR) for trauma or tumor involves corpectomy and placement of hardware to reconstitute the anterior weight-bearing stability of the spine. We report our clinical experience with thoracoscopic techniques for AVBR.

METHODS

We retrospectively analyzed patients who underwent thoracoscopic AVBR surgery for expandable cage placement. We report pathological condition, patient age, vertebral body level, operative time, estimated blood loss (EBL), and need for blood transfusion.

RESULTS

Twenty-one expandable cages were placed thoracoscopically in 15 fractures and six tumors. In fracture cases, mean age, operative time, EBL, and transfusion rate were 36.7 years, 4.9 h, 543 mL, and 7% (1/15), respectively. In tumor cases, mean age, operative time, EBL, and transfusion rate were 61.9 years, 4.9 h, 758 mL, and 17% (1/6), respectively.

CONCLUSIONS

Thoracoscopic AVBR with expandable cages can be accomplished safely with acceptable operative times and blood loss and low transfusion rates.

Endoscopic surgery on the thoracolumbar junction of the spine

The thoracolumbar junction is the section of the truncal spine most often affected by injuries. Acute instability with structural damage to the anterior load bearing spinal column and post-traumatic deformity represent the most frequent indications for surgery. In the past few years, endoscopic techniques for these indications have partially superseded the open procedures, which are associated with high access morbidity. The particular position of this section of the spine, which lies in the border area between the thoracic and abdominal cavities, makes it necessary in most cases to partially detach the diaphragm endoscopically in order to expose the operation site, and this also provides access to the retroperitoneal section of the thoracolumbar junction. A now standardised operating technique and instruments and implants specially developed for the endoscopic procedure, from angle stable plate and screw implants to endoscopically implantable vertebral body replacements, have gradually opened up the entire spectrum of anterior spine surgery to endoscopic techniques.

Endoscopic spinal tethered cord release: operative technique

PURPOSE

This study aims to describe solely endoscopic surgical techniques for the treatment of spinal pathology. Here, we present a novel endoscopic technique for surgical untethering of the spinal cord by filum sectioning and discuss endoscopic surgical management of this entity.

METHODS

Two patients (ages 8 months and 10 years) presented with leg weakness, urine and bowel dysfunction, low back and neck pain, and thickened, fatty filum terminale. The elder patient presented with clinical incontinence and abnormal urodynamic studies.

RESULTS

Both patients underwent a solely endoscopic approach using 0 degrees and 30 degrees , 4 mm in diameter and 18 cm in length rigid endoscopes via a hemilaminectomy. Intradural microdissection under a direct visualization of endoscope delivered the fatty filum into the durotomy. Electrical stimulation was performed while the lower extremities and the anal sphincter were monitored for electromyographic activity. After acquisition of positive controls, the filum was identified by the lack of sphincter and lower extremity electromyographic responses and was then cauterized and cut. Both patients had significant improvement of their preoperative symptoms, and one patient had resolution of the abnormal urodynamics and her Chiari symptoms.

CONCLUSION

Tethered spinal cords can be safely and effectively untethered endoscopically. This procedure provides the advantages of reduced soft tissue injury, less postoperative pain, minimal blood loss, a smaller incision, and a shorter hospitalization. However, whether the endoscopic untethering technique achieves benefits above those associated with the open procedure remains to be determined by a control study.

[Spinal column injuries in sport: treatment strategies and clinical results]

BACKGROUND

The management of patients with sport-related injuries of the spine is a challenging issue with regard to the ability to resume former sport activities. The current study analyses the rate of resumption of sports participation after conservative and operative treatment.

METHODS

In a 2-year period, 96 patients with sport-related injuries of the thoracic and lumbar spine were included in this prospective study. Conservative (19%) or operative treatment (81%) was performed depending on the extent, severity and instability of the trauma. The reduction, the loss of reduction over time and the VAS and Odom scores were assessed. A questionnaire was included to estimate the rate of resumption of sports participation.

RESULTS

Of the patients 91% resumed sports participation and 9% had to abandon all sport activities mostly due to neurological deficits. Minor loss of correction was found in patients with 360 degrees short segment fusions and major loss was found after conservative treatment.

CONCLUSION

The current management of injuries of the spine effectuates a high rate of resumption of sports activity following conservative or operative treatment.

ROD DEROTATION TECHNIQUES FOR THORACOLUMBAR SPINAL DEFORMITY

OBJECTIVE

The operative correction of scoliosis requires multiple intraoperative techniques and tools to achieve an adequate result. Frequently, multiple methods are used to accomplish this, such as rod cantilever techniques, in situ bending, Smith-Petersen and pedicle subtraction osteotomies, closed reduction methods, and rod derotation techniques. Rod derotation techniques will be reviewed and discussed in this article.

METHODS

A review of the available literature on anterior and posterior rod derotation is performed with a case example of the authors' experience utilizing this technique.

RESULTS

Rod derotation is one technique that can transform a pathological scoliotic curve to normal physiological kyphosis or lordosis by simply rotating a rod intraoperatively.

CONCLUSION

In this article, the authors present rod derotation as a valuable technique in the surgical arsenal for the treatment of scoliosis, including a discussion of the technique and its limitations.

Minimally invasive thoracoscopic approach for anterior decompression and stabilization of metastatic spine disease

Object

The choices available in the management of metastatic spine disease are complex, and the role of surgical therapy is increasing. Recent studies have indicated that patients treated with direct surgical decompression and stabilization before radiation have better functional outcomes than those treated with radiation alone. The most common anterior surgical approach for direct spinal cord decompression and stabilization in the thoracic spine is open thoracotomy; however, thoracotomy for spinal access is associated with morbidity that can be avoided with minimally invasive techniques like thoracoscopy.

Methods

A minimally invasive thoracoscopic approach was used for the surgical treatment of thoracic and thoracolumbar metastatic spinal cord compression. This technique allows ventral decompression via corpectomy, inter-body reconstruction with expandable cages, and stabilization with an anterolateral plating system designed specifically for minimally invasive implantation. This technique was performed in 5 patients with metastatic disease of the thoracic spine, including the thoracolumbar junction.

Results

All patients had improvement in preoperative symptoms and neurological deficits. No complications occurred in this small series.

Conclusions

The minimally invasive thoracoscopic approach can be applied to the treatment of thoracic and thoracolumbar metastatic spine disease in an effort to reduce access morbidity. Preliminary results have indicated that adequate decompression, reconstruction, and stabilization can be achieved with this technique.

Endoscopy-assisted Approaches for Anterior Column Reconstruction after Pedicle Screw Fixation of Acute Traumatic Thoracic and Lumbar Fractures

Objective:

Surgical treatment of thoracic and lumbar vertebral body fractures combines instrumentation to stabilize the fracture and an anterior reconstruction to promote fusion of the fractured spine. The aim of the present study was to show that minimally invasive thoracoscopic or endoscopy-assisted approaches to the thoracic and lumbar spine are feasible for anterior column reconstruction.

Methods:

This prospective, single-center study included 83 consecutive patients harboring 100 acute thoracic and lumbar vertebral fractures. Patients' neurological status; preoperative, postoperative, and follow-up radiographic data; and surgical data were obtained.

Results:

Fractures ranged from T5 to L5. All fractures underwent posterior pedicle screw fixation followed by a thoracoscopic or endoscopy-assisted anterior approach for anterior column reconstruction to promote fusion. Ventral graft position was correct in 45 patients and acceptable in 37 patients; one patient required a surgical repositioning. Initial correction of kyphosis was 9 degrees; during follow-up (23 ± 11 mo), the mean loss of correction was 6 degrees. In 84 minimally invasive approaches, five conversions to an open approach were necessary. Complications included one case of L1 nerve root injury, two cases of transient neurological worsening, one case of posterior wound infection, and one case of pleural empyema.

Conclusion:

The minimally invasive endoscopic approach for anterior column reconstruction is a feasible strategy in the treatment of unstable thoracic and lumbar fractures. Fracture type and the material of the anterior graft can affect long-term maintenance of correction.

Video-assisted techniques in the management of thoracolumbar fractures

The thoracolumbar junction is the most common region of the spine to be affected by injuries. Acute instability with structural damage to the anterior load-bearing spinal column and posttraumatic deformity represent the most frequent indications for surgery. A standardized operating technique with instruments and implants specially developed for the endoscopic procedure, ranging from an angled, stable plate and screw implant to endoscopically implantable vertebral body replacements, have gradually opened up the entire spectrum of anterior spine surgery to endoscopic techniques at the thoracolumbar junction.

Minimally invasive spine surgery: a historical perspective

Minimally invasive spine surgery has gained considerable momentum and increased acceptance among spine surgeons throughout the years. An understanding and awareness of the development of minimally invasive spine surgery and its role in the operative treatment of various spine conditions is imperative. This article provides a succinct historical perspective of the development of spine surgery from the more traditional, open procedures to the use of more "minimal access" or minimally invasive spine surgery procedures.

Endoscopic treatment of spinal trauma at the thoracolumbar junction

Attempts of treating unstable fractures of the thoracolumbar junction by posterior reduction and fixation alone often result in a significant loss of correction, especially in lesions where a severe destruction of the vertebral body and the intervertebral disc is present. The conventional open approaches like classic thoraco-phreno-lumbotomy produces additional iatrogenic trauma at the lateral chest and abdominal wall which not rarely leads to intercostal neuralgia, as well as post-thoracotomy syndromes. The endoscopic trans-diaphragmatic approach described below opens up the whole thoracolumbar junction to a minimally invasive procedure allowing one to perform all the procedures needed for a full reconstruction of the anterior column of the spine like corpectomy, decompression, vertebral body replacement and anterior plating. The key to address also the subdiaphragmal and retroperitoneal section of the thoracolumbar junction is a partial detachment of the diaphragm which runs along the attachment at the spine and the ribs. The technique was published first in 1998 and has been used now in 650 endoscopic procedures at the thoracolumbar junction out of a total of more than 1300 thoracoscopic operations of the spine in the BG Unfallklinik Murnau, Germany since 1996.

Two column lesions in the thoracolumbar junction: anterior, posterior or combined approach? A comparative biomechanical in vitro investigation

There are various surgical techniques for the treatment of spinal fractures in the thoracolumbar region. Several implants have been developed for anterior or posterior instrumentation. Optimal treatment of unstable thoracolumbar osseous and ligamentous injuries remains controversial. To compare the stabilizing effects of an antero-lateral, thoracoscopically implantable plate system (macsTL, Aesculap, Germany) with the stability provided by a fixateur interne (SOCON, Aesculap, Germany), this in vitro investigation examined six human bisegmental (T12-L2) spinal units. Specimens were tested intact, and with simulation of osseous lesions in the anterior and ligamentous lesions in the posterior column (combined A/B-fracture). While loaded in the main anatomical planes such as flexion/extension, left and right lateral bending and left and right axial rotation with a bending moment of 7.5 Nm in a special testing jigs, motion analysis was performed. Quantitative interpretation of the stabilizing effect was achieved using a contactless three-dimensional motion analysis system. Each specimen was tested in four different scenarios: the first step measured movements of intact spinal segments. For the second step, specimens underwent simulation of combined A/B-fracture provided with bisegmental (T12/L2) antero-lateral fixation and bone strut graft from the iliac crest. For the third step, segments were additionally stabilized by the fixateur interne. The last measurement (fourth step) was performed after removing the anterior instrumentation. Range of motion (ROM) values were compared and statistically evaluated. Compared to the intact specimens the anterior instrumentation of the combined lesion, simulated A/B-fracture, leads to a stabilizing effect in flexion/extension and lateral bending. In contrast to these findings the torsional instability increased for the upper segment and bisegmentally. A maximum rigidity, beyond intact values, was registered for each anatomical plane with the combined instrumentation: antero-lateral and fixateur interne. After removing the anterior screw plate system maximum movements, in all segments for flexion/extension and lateral bending, bisegmentally and for the upper segment in axial rotation, were less than ROM values measured with the anterior system only. With respect to these findings a combined ventro-dorsal stabilization procedure should be considered for ligamentous disruptions of the posterior column in combination with A-fractures in the thoracolumbar junction.

Endoscopic surgery on the thoracolumbar junction of the spine

The thoracolumbar junction is the section of the truncal spine most often affected by injuries. Acute instability with structural damage to the anterior load-bearing spinal column and post-traumatic deformity represents the most frequent indications for surgery. In the past few years, endoscopic techniques for these indications have partially superseded the open procedures, which are associated with high access morbidity. The particular position of this section of the spine, which lies in the transition area between the thoracic and abdominal cavities, makes it necessary in most cases to partially detach the diaphragm endoscopically in order to expose the surgical site, and this also provides access to the retroperitoneal section of the thoracolumbar junction. A now standardised operating technique, instruments and implants specially developed for the endoscopic procedure, from angle stable plate and screw implants to endoscopically implantable vertebral body replacements, have gradually opened up the entire spectrum of anterior spine surgery to endoscopic techniques.

Efficacy of surgical decompression in regard to motor recovery in the setting of conus medullaris injury

BACKGROUND/OBJECTIVE

An assessment of neurological improvement after surgical intervention in the setting of traumatic conus medullaris injury (CMI).

METHODS

A retrospective evaluation of a cohort of patients with a blunt traumatic CMI from T12 to L1. The neurologic and functional outcomes were recorded from the acute hospital admission to the most recent follow-up. Data collected included age, level of injury, neurologic examination according to the Frankel grading system and motor index score, and the mechanism and timing of CMI decompression.

RESULTS

A total of 24 patients with a mean age of 27 years (men, 87%) were identified. The most common level of bony injury was L1, and the most frequent mechanism of injury was a motor vehicle crash. Before surgical intervention, 16 of 24 patients (66.7%) had a complete neurological deficit below the level of injury. The median interval from injury to surgery was 6 days (range, 7 hours to 390 days). Decompression, fusion, and adjunctive internal fixation were the most common surgical procedures. Median length of follow-up was 32 months after surgery. Improvement in spinal cord and bladder function was seen in 41.6% and 63.6% of patients, respectively. Root recovery was seen in 83.3% of patients.

CONCLUSIONS

In the setting of CMI, no correlation between the timing of surgical decompression and motor improvement was identified. Root recovery was more predictable than spinal cord and bladder recovery.

Neuroendoscopy for spinal disorders: a brief review

Neuroendoscopy has grown rapidly in the last 20 years as a therapeutic modality for treating a variety of spinal disorders. Spinal endoscopy has been widely used to treat patients with cervical, thoracic, and lumbosacral disorders safely and effectively. Although it is most commonly used with minimally invasive lumbar spine surgery, endoscopy has gained widespread acceptance for the treatment of thoracic disc herniations and for anterior release and rod implantation in the correction of thoracic spinal deformity. The authors review the use of endoscopy in spine surgery and in the treatment of spinal disorders as well as in the treatment of intrathoracic nonspinal lesions. Endoscopy has some significant advantages over open or other minimally invasive techniques in that it can allow for better visualization of the lesion, smaller incision sizes with reduced morbidity and mortality, reduced hospital stays, and ultimately lower cost. In addition, spinal endoscopy allows observers and operating room staff to be more involved in each case and fosters education. Spinal endoscopy, like any novel modality, carries with it additional risks and the surgeon must always be prepared to convert to an open procedure. The learning curve for spinal endoscopy is steep and the procedure should not be attempted alone by a novice surgeon. Nevertheless, with training and experience, the spine surgeon can achieve better outcomes, reduced morbidity, and better cosmesis with spinal endoscopy, and the operating times are comparable to open procedures. As technology evolves and more experience is obtained, neuroendoscopy will likely achieve further roles as a mainstay in spine surgery.

Thoracoscopic spine surgery for decompression and stabilization of the anterolateral thoracolumbar spine

The anterior thoracolumbar spine can be exposed via a variety of approaches. Historically, open anterolateral or pos-terolateral approaches have been used to gain access to the anterior thoracolumbar spinal column. Although the exposure is excellent, open approaches are associated with significant pain and respiratory problems, substantial blood loss, poor cosmesis, and prolonged hospitalization. With the increasing use of the endoscope in surgical procedures and recent advances in video-assisted thoracoscopic surgery, minimally invasive thoracoscopic spine surgery has been developed to decrease the morbidity associated with open thoracotomy. The purpose of this article is to illustrate the surgical technique of a minimally invasive thoracoscopic approach to the anterolateral thoracolumbar spine and to discuss its potential indications and contraindications in patients with diseases involving the anterior thoracic and lumbar regions.

Efficacy of surgical decompression in the setting of complete thoracic spinal cord injury

BACKGROUND/OBJECTIVE

An assessment of neurological improvement after surgical intervention in the setting of traumatic thoracic spinal cord injury (SCI).

METHODS

A retrospective evaluation of a nonconsecutive cohort of patients with a thoracic SCI from T2 to T11. The analysis included a total of 12 eligible patients. The neurologic and functional outcomes were recorded from the acute hospital admission to the most recent follow-up. Data included patient age, level of injury, neurologic examination according to the Frankel grading system, the performance of surgery, and the mechanism of the time-related SCI decompression.

RESULTS

All patients had a complete thoracic SCI. The median interval from injury to surgery was 11 days (range, 1-36 days). Decompression, bone fusion, and instrumentation were the most common surgical procedures performed. The median length of follow-up was 18 months after surgery (range, 9-132 months). Motor functional improvement was seen in 1 patient (Frankel A to C).

CONCLUSION

Surgical decompression and fusion imparts no apparent benefit in terms of neurologic improvement (spinal cord) in the setting of a complete traumatic thoracic SCI. To better define the role of surgical decompression and stabilization in the setting of a complete SCI, randomized, controlled, prospective studies are necessary.