Biomechanical in vitro comparison of different mono- and bisegmental anterior procedures with regard to the strategy for fracture stabilisation using minimally invasive techniques

One-stage posterior debridement, bone grafting fusion, and mono-segment vs. short-segment fixation for single-segment lumbar spinal tuberculosis: minimum 5-year follow-up outcomes

BACKGROUND

To compare the clinical and radiological outcomes between posterior mono-segment and short-segment fixation combined with one-stage posterior debridement and bone grafting fusion in treating single-segment lumbar spinal tuberculosis (LSTB).

METHODS

Sixty-two patients with single-segment LSTB treated by a posterior-only approach were divided into two groups: short-segment fixation (Group A, n = 32) and mono-segment fixation (Group B, n = 30). The clinical and radiographic outcomes were analyzed and compared between the two groups.

RESULTS

The intraoperative bleeding volume, operation time, and hospitalization duration were lower in Group B than in Group A. All patients achieved the bony fusion criteria. The visual analog scale score, Japanese Orthopedic Association score, and Oswestry Disability Index were substantially improved 3 months postoperatively and at the last visit in both groups, with no significant difference between the two groups (P > 0.05). Kirkaldy-Willis functional evaluation at the final follow-up demonstrated that all patients in both groups achieved excellent or good results. The difference in the angle correction rate and correction loss between Groups A and B was not significant (P > 0.05).

CONCLUSIONS

One-stage posterior debridement, bone grafting fusion, and mono-segment or short-segment fixation can provide satisfactory clinical and radiological outcomes. Mono-segment fixation is more suitable for the treatment of single-segment LSTB because the lumbar segments with normal motion can be preserved with less trauma, a shorter operation time, shorter hospitalization, and lower costs.

Revision strategy and follow-up for implant failure in a case of combined anterior and posterior reconstruction after three-level en bloc vertebral body replacement and replacement of the aorta for chondrosarcoma of the thoracic spine

OBJECTIVE

In 2013, we reported a case of combined anterior and posterior reconstruction after three-level en bloc vertebral body replacement and replacement of the aorta for chondrosarcoma of the thoracic spine. Eight years after, we observed an implant failure and now report on revision strategy and 2-year follow-up (f/u) after revision.

METHODS

We report about the 2-year f/u of the same now 51-year-old gravedigger who needed to undergo revision surgery after implant failure. We did a combined anterior and posterior correction vertebral interbody fusion by (1) removal of broken screws in Th9 and L2, removal of broken titanium bars, correction of kyphosis, enhancement of the vertebral interbody fusion from Th8 to L4 using monoaxial titanium screws and cancellous bone transplantation and (2) removal of the broken plate and the loose cage, implantation of a novel expandable PEEK cage from Th11 to L1 and anterior stabilization from Th9/10 to L2/3, as well as autologous and allogeneic cancellous bone transplantation.

RESULTS

Two years after revision surgery, the patient presented fully reintegrated without any complains. No painkillers needed to be taken. Pain was reported with 2 out of 10 on the VAS.

CONCLUSION

Both procedures offer a good primary stabilization with excellent pain reduction and good return to life. Limited information on long-term survivors is known. Therefore, the theoretical advantage of a biological solution needs to be checked in the long-term f/u for consistency.

Challenging the Conventional Standard for Thoracic Spine Range of Motion: A Systematic Review

BACKGROUND

Segmental motion is a fundamental characteristic of the thoracic spine; however, studies of segmental ranges of motion have not been summarized or analyzed. The purpose of the present study was to present a summary of the literature on intact cadaveric thoracic spine segmental range of motion in each anatomical plane.

METHODS

A systematic MEDLINE search was performed with use of the terms "thoracic spine," "motion," and "cadaver." Reports that included data on the range of motion of intact thoracic human cadaveric spines were included. Independent variables included experimental details (e.g., specimen age), type of loading (e.g., pure moments), and applied moment. Dependent variables included the ranges of motion in flexion-extension, lateral bending, and axial rotation.

RESULTS

Thirty-three unique articles were identified and included. Twenty-three applied pure moments to thoracic spine specimens, with applied moments ranging from 1.5 to 8 Nm. Estimated segmental range of motion pooled means ranged from 1.9° to 3.8° in flexion-extension, from 2.1° to 4.4° in lateral bending, and from 2.4° to 5.2° in axial rotation. The sums of the range of motion pooled means (T1 to T12) were 28° in flexion-extension, 36° in lateral bending, and 45° in axial rotation.

CONCLUSIONS

The pooled ranges of motion were similar to reported in vivo motions but were considerably smaller in magnitude than the frequently referenced values reported prior to the widespread use of biomechanical testing standards. Improved reporting of biomechanical testing methods, as well as specimen health, may be beneficial for improving on these estimations of segmental cadaveric thoracic spine range of motion.

Surgical treatment for mono-segmental lumbar tuberculosis by single-stage posterior debridement, compact bone grafting and posterior single-segment fixation

PURPOSE

To evaluate the efficacy and safety of single-stage posterior debridement, compact bone grafting and posterior single-segment fixation for the treatment of mono-segmental lumbar tuberculosis.

METHODS

We enrolled 32 patients with mono-segmental lumbar tuberculosis from January 2005 to April 2011. The severity of damage to the vertebral bodies is not more than 2/3 height. All the patients were treated by single-stage posterior debridement, compact bone grafting and posterior single-segment fixation.

RESULTS

Patients were followed 21-63 months (43.5±9.5 months). The average Cobb angle decreased to 5.3±3.0° postoperatively from 22.1±6.1° preoperatively. Meanwhile, average 1.8±1.0° loss was observed at last visit. Fusion occurred at 3-9 months (mean 5.1 months). All patients with preoperative neurologic deficit recovered in different degree. 1 with grade B recovered to grade D; 2 with grade C recovered to grade E; 18 with grade D recovered to grade E. No mortality occurred. One patient experienced anti-tuberculosis drug-induced liver dysfunction which was managed successfully with modified anti-TB treatment and hepato-protective treatment. The Oswestry Disability Index decreased from 40.1±4.0 preoperatively to 13.7±3.1 postoperatively.

CONCLUSIONS

Single-stage posterior debridement, compact bone grafting and posterior single-segment fixation is an effective method for the treatment of mono-segmental lumbar tuberculosis.

Anterior debridement and bone grafting with posterior single-segment internal fixation for the treatment of mono-segmental spinal tuberculosis

BACKGROUNDS

Short-segment or long-segment fixation is the most commonly used method for treating spinal tuberculosis with damage to a single motor segment (mono-segmental spinal tuberculosis). However, these methods incorporate several of the normal adjacent motor segments surrounding the damaged motor segments during surgery and subsequent healing, leaving them prone to adjacent segment degeneration. A single-segment fixation approach may offer an alternative solution for the surgical treatment of mono-segmental spinal tuberculosis.

PATIENTS AND METHODS

102 Retrospectively studied patients with mono-segmental spinal tuberculosis were divided into two groups: single-segment (the fixed/fused range was limited to only one damaged motion segment n=54) and short-segment (the fixed/fused range included both the damaged segment and the normal motion segment located above and below the damaged motion segment, respectively n=48). Responses to postoperative chemotherapy and changes in the Cobb angle for kyphosis, fusion time, and Frankel grading were recorded. Each patient's quality of life and ability to return to work, as determined by the Oswestry Disability Index (ODI), were also evaluated.

RESULTS

At the end of the final follow-up, the degree of correction was 12.69±4.56° and 13.44±4.53° for the single-segment and short-segment groups, respectively, with a loss of 1.80±1.19° and 1.60±1.16°, respectively. The differences between the two groups were not significant (P>0.05). The average bone healing time was 4.4±0.9 months in the single-segment group and 4.4±1.0 months in the short-segment group. The Frankel grade for neurologic function returned to normal in >94% of patients. The ODI was 13.5±2.8 and 14.1±3.7 for the single-segment and short-segment groups, respectively. The rates of improvement were 64.0±5.5% and 65.9±4.9% for the single-segment and short-segment groups, respectively. The differences between the two groups were not significant (P>0.05).

CONCLUSION

After bone fusion, single-segment fixation is effective in restoring and maintaining spinal stability and retains normal motion segment more than short-segment fixation approach. Strict adherence to the clinical indications must occur in order to optimize the overall outcome.

[Biomechanical aspects of complex reconstructions following radical resection of thoracolumbar spinal tumors]

The total number of spinal tumors has increased over the past decade. However, the average survival time of tumor patients has increased due to improvements in the multidisciplinary treatment regimes. Therefore, radical tumor resection and complex reconstruction were developed in spinal surgery. Various reconstructive options for the throracolumbar spine are nowadays available and are depicted in this article. The success of complex reconstructive surgery relies on biomechanical principles and reconstruction is dependent on the size and location of the lesion, bone porosity and implant systems used. Special emphasis of this article focuses on en bloc vertebrectomy which is the most radical approach of spinal tumor surgery. The biomechanical aspects of different types of lesions and the reconstructive options are discussed in the context of the currently published literature.

Management considerations and strategies to avoid complications associated with the thoracoscopic approach for corpectomy

The thoracoscopic approach to the anterior spine is a practical and valuable means of approaching ventral spinal lesions but demands advanced technical skills and fine hand-eye coordination that is usually acquired with experience. A mutual understanding of all the ventilatory and surgical steps allows for an organized orchestration between the anesthesiologist and surgeon, which ultimately helps minimize potential complications. Despite a concerted effort by all involved to avoid risks, thoracoscopic surgery is associated with complications for which the surgical team should be cognizant. In this paper, the authors detail the operative technique of vertebral corpectomy and interbody fusion via the thoracoscopic approach for the treatment of ventral spinal pathology involving the thoracic and lower lumbar spine, discuss complications known to occur with the thoracoscopic approach, and present means to help avoid them.

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.

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.

Extent of corpectomy determines primary stability following isolated anterior reconstruction in a thoracolumbar fracture model

BACKGROUND

Based on the development of minimal-invasive techniques and introduction of new implants enabling secure reconstruction an increasing number of patients are treated by isolated anterior column surgery. Most biomechanical studies dealing with thoracolumbar fracture models use worst-case scenarios of complete corpectomies to simulate vertebral body defects neglecting the influence of remaining cortical bone in partial corpus instability. Using a standardized partial and total corpectomy model we investigated the effect of the extent of corpectomy on stiffness in an anterior reconstruction model.

METHODS

Twelve human thoracolumbar specimens (Th11-L3) were loaded in a spine simulator with pure moments in the three motion planes. Following intact testing partial corp- and discectomy and later complete corpectomy of L1 were performed. Defects were instrumented by vertebral body replacements and additional anterior plating systems bridging the defect from Th12 to L2. Intersegmental rotations were measured between Th12 and L2.

FINDINGS

Significantly (P<0.05) increased range of motion was found in reconstructions of total compared to partial corpectomy. Total corpectomy reconstructions showed solely in lateral bending a significant reduction of range of motion compared to the intact state, while in axial rotation and flexion/extension it was significantly increased. Partial corpectomy reconstructions resulted in significantly reduced range of motion for lateral bending and flexion/extension compared to the intact specimen.

INTERPRETATION

Isolated anterior reconstructions of the thoracolumbar spine revealed sufficient stiffness in the partial vertebral corpus defect. In contrast, total corpectomy did not show an adequate stiffness. Especially in regard to rotational stiffness additional posterior fixation has to be recommended.

[Can failed back surgery be prevented? Psychological risk factors for postoperative pain after back surgery]

Aside from the surgical technique used, the development of peri- and postoperative pain and impairments in patients following intervertebral disk surgery is also determined to a crucial extent by psychological factors. Based on a systematic literature review, we checked whether evidence-based recommendations could be deduced on how to take into account psychological risk factors in back surgery in order to avoid postoperative complications, such as failed back surgery syndrome. The current state of research suggests three groups of risk factors: (1) negative psychological factors, (2) preexisting pain chronification, and (3) psychological disorders. In the case of elective intervertebral disk surgery, these factors should therefore be determined and identified preoperatively and taken into account in the indication for surgery. Multimodal treatments could conceivably prove to be more effective, or else psychological pain management therapy might be considered prior to surgery so as to avoid postoperative complications. If surgery is medically unavoidable despite existing risk factors, postoperative treatment should incorporate psychological pain management therapy at an early stage in the context of a multidisciplinary approach.

Angular stable anterior plating following thoracolumbar corpectomy reveals superior segmental stability compared to conventional polyaxial plate fixation

STUDY DESIGN

Biomechanical in vitro testing of primary and secondary stability in 12 human thoracolumbar spinal specimens using a spine simulator.

OBJECTIVE

In a corpectomy model anterior plate systems were investigated for their ability to restore spinal stability particularly focusing on the influence of angular stability, bone mineral density (BMD) and failure mode.

SUMMARY OF BACKGROUND DATA

The concept of isolated anterior column reconstruction following thoracolumbar fractures using newly developed minimally invasive spine surgical techniques has attracted major clinical interest. In analogy to angular stable plate systems in long bone fixation the application of locking plates to the spine is aimed to limit loss of reduction and to improve stability.

METHODS

Twelve human spinal specimens (Th11-L3) were tested in a 6-degree-of-freedom spine simulator under pure moments of 7.5 Nm to investigate primary and secondary stiffness of 2 different anterior reconstruction options: (1) Synex II cage and MACS TL polyaxial anterior plating system, (2) Synex II cage and ArcoFix angular stable anterior plating system. An increasing 4-step cyclic loading model was included.

RESULTS

The angular stable plate system showed superior stability compared to the nonangular system in axial rotation and lateral bending. Flexion/extension loading demonstrated no difference between the systems in range of motion. A positive correlation between BMD and the number of load cycles until failure for the nonangular stable system (R2 = 0.90) was found. Different failure modes were investigated for the plating systems. The MACS system showed loosening at the connection between screw and plate inducing tilting under flexural load and final failure. The ArcoFix system revealed increased stability under cyclic loading and failed by parallel sintering to the endplate.

CONCLUSION

Anterior angular stable fixation showed higher primary and secondary stability following thoracolumbar corpectomy. In specimens with lower BMD the use of angular stable systems substantially increased stability. Angular stable systems, however, differ in the way of construct failure.

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.

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.

[Facet blockade, peridural and periradicular pain therapy]

More than 80% of vertebrogenic lumbar pain is unspecific and can only be attributed to a specific anatomic structure with difficulty. The pain can emanate from the intervertebral discs, intervertebral and sacroiliac (SI) joints, musculature, and ligaments. In a maximum of 7% of cases, the pain is radicular (4% due to intervertebral discs and 3% caused by stenoses). In 7-15% of cases, the pain's origin is located in the region of the vertebral joints and in up to 15% in the region of the SI joint. Although the overwhelming majority of pain has no clear structural cause, infiltrations of medications and nerve blockades are frequently employed. The efficacy of these procedures has however not been verified in controlled studies with the exception of epidural injection of corticosteroids for radicular pain. Epidural and epiradicular application of corticosteroids appear to be effective for radicular pain, at least on a short-term basis, although controlled studies have yielded controversial results. The difficulty lies partly in the exact placement at the affected root for applying the medication. This is hardly possible with a caudal injection, while with a lumbar peridural injection and periradicular injections it is only possible under X-ray control or even better CT guidance.

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.