Percutaneous surgery for thoraco-lumbar fractures in ankylosing spondylitis: Study of 31 patients

BACKGROUND

The risk of vertebral fracture is increased 4-fold in patients with ankylosing spondylitis (AS). Diagnostic challenges and the vulnerability associated with AS combine to generate high morbidity and mortality rates. The objective of this study was to assess the outcome of percutaneous thoraco-lumbar fracture surgery in patients with AS, in terms of quality of life, fracture healing, and complications.

HYPOTHESIS

Percutaneous surgery used to treat thoraco-lumbar fractures in patients with AS reliably provides fracture healing, preserves self-sufficiency, and minimises post-operative complications.

METHODS

Two centres included 31 patients with AS who were managed by percutaneous surgery for thoraco-lumbar fractures in 2013-2015. The data were reviewed retrospectively, although admission data were collected prospectively. Clinical outcomes were assessed by comparing the values at baseline and last follow-up of three variables: the Parker score, the visual analogue scale (VAS) pain score, and the EuroQol five dimensions (EQ-5D) quality-of-life score. Computed tomography was performed 1 year after surgery to evaluate bone healing, screw position, and implant loosening. Intra- and post-operative complications were recorded.

RESULTS

The 31 patients had a mean age at surgery of 75.1 years, a mean follow-up of 35.6 months, and a minimum follow-up of 12 months. Three patients died during follow-up. Mean hospital stay duration was 6 days. Cemented screw fixation was used in 18 patients. At last follow-up, all patients had recovered their self-sufficiency; the mean Parker score was 7.14, compared to 6.73 at baseline, the mean VAS pain score was 1.8, and the mean EQ-5D score decrease versus baseline was 0.07 (P=0.02). Bone healing was consistently achieved. Loosening of an uncemented pedicle screw was noted in 1 patient. Of the 228 screws implanted, 6 (2.6%) were improperly positioned, including 1 within the spinal canal in a patient free of neurological manifestations. Asymptomatic cement leakage was noted in 2 patients.

DISCUSSION

Percutaneous fixation of thoraco-lumbar fractures in patients with AS is a reliable method that produces a high healing rate and allows prompt patient mobilisation with preservation of self-sufficiency. The post-operative complication rate is low.

LEVEL OF EVIDENCE

IV, retrospective observational study.

Chondroblastoma of the thoracic spine: a rare location. Case report with radiologic-pathologic correlation

Chondroblastoma is a rare benign cartilage neoplasm that arises from the appendicular skeleton in the vast majority of the cases (80%). Chondroblastoma of the spine is an even more rare condition (30 cases reported), and vertebral chondroblastomas, unlike chondroblastomas of the extremities, present with the appearance of an aggressive tumor on CT and MR imaging and occur at least a decade later. Even though vertebral chondroblastomas are very uncommon tumors, they should nonetheless be included in the differential diagnosis when encountered with an aggressive vertebral mass, and a histological confirmation should be performed. We present a case of chondroblastoma of the thoracic spine of a 27-year-old female for which detailed radiologic-pathologic correlation was obtained.

Comparison between total disc replacement and hybrid construct at two lumbar levels with minimum follow-up of two years

INTRODUCTION

Lower back pain due to degenerative disc disease is a therapeutic challenge in young patients. Although arthrodesis is currently the gold standard for surgical treatment, improvement in total disc replacement techniques makes it possible to preserve segmental mobility with good results in one-level surgery. Nevertheless, the French National Health Authority does not recommend total disc replacement for multilevel surgery. Thus, hybrid constructs that combine one-level disc replacement with arthrodesis have been developed for multilevel indications.

HYPOTHESIS

The outcome of two-level lumbar disc arthroplasty does not differ from hybrid constructs.

METHODS

The clinical and radiographic outcomes of disc arthroplasty were compared to hybrid constructs for two-level degenerative disc disease in 72 patients after a continuous follow-up of at least 2 years. The patients were divided into two groups that were similar for the indication and type of implants.

RESULTS

There was no statistical difference in pain relief (-3.9 points versus -3.5 points for lumbar VAS) or reduction in ODI (-29.5% versus -27.0%) between TDR and hybrid constructs, respectively. There was no statistical difference in range of motion at the level of arthroplasty (8.4° versus 7.6°) and no kinematic dysfunction was identified. The re-operation rate at two years for persistent lumbar pain was respectively 6.7% for two-level disc arthroplasty and 4.3% for hybrid constructs. The complication rate was 4.8% and 8.7% respectively.

DISCUSSION

No difference was found in this comparison of two homogeneous series between two-level disc arthroplasty and hybrid constructs for the treatment of degenerative disc disease after two years of follow-up. Two-level disc arthroplasty may be an alternative for young patients depending on an evaluation of long-term results.

LEVEL OF EVIDENCE

Cohort observational study level III.

Cervical sagittal alignment in adult hyperkyphosis treated by posterior instrumentation and in situ bending

BACKGROUND

In the normal adult spine, a link between thoracolumbar and cervical sagittal alignment exists, suggesting adaptive cervical positional changes allowing horizontal gaze. In patients with thoracic hyperkyphosis, cervical adaptation to sagittal global alignment might be different from healthy individuals. However, this relationship has not clearly been reported in hyperkyphotic deformity.

PURPOSE

The purpose of this study was to identify cervical sagittal alignment types observed on radiographs in young adults with thoracic hyperkyphosis. The relationship between cervical and thoracolumbar alignment as well as the effect of posterior instrumentation and adaptive positional changes of the mobile cervical segment were retrospectively analyzed.

PATIENTS AND METHODS

Twenty-three patients (32.7 years; 5-year follow-up) were included. Full spine radiographic measurements were: T1 slope, T1-T4 kyphosis, T4-T12 kyphosis, L1-S1 lordosis, pelvic incidence, pelvic tilt, sacral slope, SVA C7, SVA C2, lordosis between C0-C2, C2-C7, C2-C4 and C4-C7. A Bayesian model and Spearman correlation were used.

RESULTS

Two alignment types existed: cervical lordosis (group A) and cervical kyphosis (group B). Preoperatively, T4-T12 kyphosis and L1-S1 lordosis were significantly higher in group A: 76.6° versus 59.4° and -72.8° versus -65.8° (probability of>5° difference P (β>5)>0.95). Pelvic incidence was higher in group A (49.8° versus 44.2°) and C0-C2 lordosis in group B (-29.4° versus -21.6°). A significant correlation existed between: T4-T12 kyphosis and C2-C7 lordosis, L1-S1 lordosis and pelvic incidence, C2-C7 lordosis and T1 slope, C2-C7 lordosis and T1-T4 kyphosis. Postoperatively, T4-T12 kyphosis decreased by 33.1° P (β>5)=0.9995), L1-S1 lordosis decreased by 17.7° (P (β>5)=0.961), T1-T4 kyphosis increased by 14.1° (P (β>5)=0.973). SVA C2 (translation) increased by 13.8mm. C0-C2 lordosis (head rotation) remained unchanged. Six patients changed cervical alignment. PJK occurred in 15 patients, unrelated to cervical alignment or proximal instrumentation level.

DISCUSSION

Two cervical alignment types, lordotic or kyphotic, were observed thoracic hyperkyphosis patients. This alignment was mainly triggered by the amount of thoracic kyphosis and lumbar lordosis, linked to pelvic incidence. Moreover, the inclination of the C7-T1 junctional area plays a key role in the amount of cervical lordosis. The correction of T4-T12 kyphosis induced compensatory modifications at adjacent segments: T1-T4 kyphosis increase (PJK) and L1-S1 lordosis decrease. Global spino-pelvic alignment and head position did not change in the sagittal plane. The cervical spine tented to keep in its preoperative position in most patients.

LEVEL OF EVIDENCE

Level IV.

Pullout characteristics of percutaneous pedicle screws with different cement augmentation methods in elderly spines: An in vitro biomechanical study

BACKGROUND

Vertebroplasty prefilling or fenestrated pedicle screw augmentation can be used to enhance pullout resistance in elderly patients. It is not clear which method offers the most reliable fixation strength if axial pullout and a bending moment is applied. The purpose of this study is to validate a new in vitro model aimed to reproduce a cut out mechanism of lumbar pedicle screws, to compare fixation strength in elderly spines with different cement augmentation techniques and to analyze factors that might influence the failure pattern.

MATERIALS AND METHODS

Six human specimens (82-100 years) were instrumented percutaneously at L2, L3 and L4 by non-augmented screws, vertebroplasty augmentation and fenestrated screws. Cement distribution (2 ml PMMA) was analyzed on CT. Vertebral endplates and the rod were oriented at 45° to the horizontal plane. The vertebral body was held by resin in a cylinder, linked to an unconstrained pivot, on which traction (10 N/s) was applied until rupture. Load-displacement curves were compared to simultaneous video recordings.

RESULTS

Median pullout forces were 488.5 N (195-500) for non-augmented screws, 643.5 N (270-1050) for vertebroplasty augmentation and 943.5 N (750-1084) for fenestrated screws. Cement augmentation through fenestrated screws led to significantly higher rupture forces compared to non-augmented screws (P=0.0039). The pullout force after vertebroplasty was variable and linked to cement distribution. A cement bolus around the distal screw tip led to pullout forces similar to non-augmented screws. A proximal cement bolus, as it was observed in fenestrated screws, led to higher pullout resistance. This cement distribution led to vertebral body fractures prior to screw pullout.

CONCLUSION

The experimental setup tended to reproduce a pullout mechanism observed on radiographs, combining axial pullout and a bending moment. Cement augmentation with fenestrated screws increased pullout resistance significantly, whereas the fixation strength with the vertebroplasty prefilling method was linked to the cement distribution.

Management of thoracolumbar spine fractures with neurologic disorder

Thoracic and lumbar fractures represent approximately 50% of neurologic spinal trauma. They lead to paraplegia or cauda equina syndrome depending on the level injured. In the acute phase, the extension of spinal cord lesions should be limited by immediately treating secondary systemic injury factors. Quick recovery of hemodynamic stability, with mean arterial blood pressure>85 mm Hg, appears essential. There is no clinical evidence in favor of high-dose corticosteroid protocols. Their effect on neurologic recovery is unproven, whereas they lead to a higher rate of secondary septic and pulmonary complications. Incomplete deficits (ASIA B-D) require urgent surgery. There is no consensus with regard to complete paraplegia (ASIA A), but early surgery can enable neurologic recovery in some cases. The principle of surgical treatment is based on spinal cord decompression, instrumentation and fracture reduction. Early stabilization of the spine improves respiratory function and shortens the duration of mechanical ventilation and thus intensive care unit stay. Depending on the severity of associated lesions, early surgery within 48 hours is beneficial in polytrauma patients. Percutaneous instrumentation combined with mini-open posterior decompression stabilizes the spine, limiting approach-related morbidity.

Posterior surgery in high-grade spondylolisthesis

INTRODUCTION

High-grade L5-S1 spondylolisthesis alters sagittal spinopelvic balance, which can cause low back pain and progressive neurologic disorder. The present study assessed spondylolisthesis reduction and maintenance over time with L4-S1 versus L5-S1 fusion using a lever-arm system and posterior fusion combined with lumbosacral graft.

MATERIALS AND METHODS

Forty patients were operated on for symptomatic high-grade spondylolisthesis, 34 of whom had full pre- and post-operative radiological analysis, with a mean follow-up of 5.4years. There were 9 L5-S1 and 25 L4-S1 instrumentations. Analysis of spinopelvic and slipping parameters and the evolution of segmental lordosis compared results between L5-S1 and L4-S1 instrumentation.

RESULTS

Mean Taillard spondylolisthesis index decreased from 64% to 37% (P=0.0001). Overall sagittal spinopelvic balance was not significantly changed. Overall L1-S1 and segmental L4-L5 lordosis were not affected by instrumentation. Mean L5-S1 segmental lordosis increased from 11° to 18°. There was loss of reduction from 19° to 14° with L5-S1 instrumentation, in contrast to maintained reduction with L4-S1 instrumentation (P=0.006).

CONCLUSION

The lever-arm system provided anterior-posterior reduction of spondylolisthesis and corrected slippage. Postoperative change in overall sagittal spinopelvic balance was slight and constant. Posterior L4-S1 fusion provided better long-term control of L5-S1 lordosis reduction than the shorter L5-S1 fusion. Retrospective study of level IV.

Update on the surgical management of Pott's disease

One-third of the world's population is infected with Mycobacterium tuberculosis. Data reported in 2011 indicate, for the first time, a decline in cases of tuberculosis, despite persistent inequalities across geographic areas and increasing rates of drug resistance. Osteo-articular tuberculosis affects the spine in half the cases. Pharmacotherapy must be combined with surgery in patients with spinal cord or nerve root compression, large abscesses, or marked anterior column osteolysis with kyphosis and instability. The quality of debridement and bony fusion is optimal when the anterior approach is used. Posterior fixation is the best means of achieving reduction followed by stable sagittal alignment over time. New treatment strategies combine conventional surgical methods, closed interventional radiology procedures for drainage and spinal cord decompression, and percutaneous fixation.

Fracture in ankylosing spondylitis after minor trauma: radiological pitfalls and treatment by percutaneous instrumentation. A case report

Patients with ankylosing spondylitis may experience spinal fractures even after minor injuries. The diagnosis of non-dislocated spinal fracture is based on clinical symptoms and radiological findings. Difficulties in interpreting the imaging studies can result in considerable diagnostic delays. We describe the steps of the radiological diagnosis in a patient with a fracture of L2 that was not visible on standard lumbar spine radiographs. Magnetic resonance imaging (MRI) T2 STIR sequences allowed determining the location and showed signs of a recent fracture. Then, MRI T1 images and computed tomography provided a detailed evaluation of the fracture line. In patients with ankylosing spondylitis, fracture instability is common, making surgical treatment mandatory. Open surgery is associated with substantial rates of infection and implant loosening. Percutaneous instrumentation has not yet been evaluated for the treatment of spinal fractures in patients with ankylosing spondylitis. This minimally invasive surgical technique enables multilevel internal fixation and may constitute an interesting alternative to open surgery.

Is preoperative embolization a prerequisite for spinal metastases surgical management?

BACKGROUND

Preoperative embolization decreases the intraoperative risk of hemorrhage in spinal decompression surgery of hypervascular metastases such as renal cell carcinoma. There is no consensus concerning embolization in other metastases. The purpose of this study was to compare the intraoperative amount of blood loss in embolized versus non-embolized patients, seeking for differences depending on the primary tumor and the extent of surgery.

PATIENTS AND METHODS

Ninety-three patients, average age 60.5 years, were operated. The origins of metastases were: 28 breast cancer (30.1%), 19 pulmonary carcinoma (20.4%), 16 renal cell carcinoma (17.2%), 30 other cancers (32.3%). Surgical procedures were: 52 thoracolumbar laminectomies with instrumentation, 29 thoracolumbar corpectomies or vertebrectomies, 12 cervical corpectomies. A preoperative microsphere embolization was performed in 35 patients. Blood loss was evaluated by: blood volume in surgical aspiration devices, number of transfused packed red blood cells units and hemoglobin variation during surgery.

RESULTS

Renal metastases were systematically embolized. In the breast group, there was no significant difference (P>0.05) in blood loss between embolization versus non-embolization. In the pulmonary group and in other metastases, no difference was found either. The extent of surgery (corpectomy/vertebrectomy versus thoracolumbar instrumentation and cervical corpectomy) increased bleeding: breast 1775ml versus 778ml and 600ml respectively (P=0.048), pulmonary 2500ml versus 430ml and 180ml (P=0.020), renal 3346ml versus 1175ml and 780ml (P=0.036) and others 1550ml versus 474ml and 400ml (P=0.020).

CONCLUSIONS

Embolization decreases the risk of hemorrhage in highly vascularized metastases such as renal cell carcinoma. A benefit of embolization was not found for metastases of breast or pulmonary tumors. As far as other metastases, thyroid carcinoma should be analyzed on a greater cohort. The extent of surgery remains an important risk factor for intraoperative bleeding. A preoperative angiogram should be carried out in all types of metastases prior to a thoracolumbar corpectomy or vertebrectomy to perform an embolization if the tumor is hypervascular.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Should post-traumatic thoracolumbar Frankel A paraplegia be operated as an emergency? Report of three cases and review of the literature

Spinal cord injury is an important contributing factor to morbidity. The thoracolumbar junction is a highly vulnerable axial region due to the biomechanical stresses and the risk of conus medullaris injuries in some cases. In the event of an incomplete neurological injury and if the patient's condition is stable, emergency surgical treatment should be considered. Yet, no clear consensus has emerged regarding the treatment modalities of complete injuries but surgical management is advocated to maximize neurological recovery and reduce the risk of decubitus ulcer formation. We report on the cases of three patients with L1 Frankel A paraplegia resulting from injury to the conus medullaris, treated within the first 6 hours from injury and demonstrating a very satisfactory neurological recovery since independent walking could be resumed at 2.5 years follow-up. Persistent urinary sphincter dysfunctions were observed in two of these patients. Early surgical management appears as an important predictive factor for neurological recovery in conus medullaris injuries. We believe that delayed surgical management in patients with complete paraplegia could be an inappropriate treatment option, which should be further studied.

[Dynamic instrumentation of the lumbar spine. Clinical and biomechanical analysis of success factors]

Total disc replacement and posterior dynamic stabilization represent alternatives to lumbar spinal fusion which should reduce the risk of adjacent segment degeneration. Disc replacement is indicated for pure discopathy without facet joint degeneration. Spinopelvic balance influences the implant's biomechanics. Therefore pelvic incidence, sacral slope, segmental lordosis and the mean axis of rotation need to be considered. Dynamic stabilization is indicated in moderate discopathy and facet joint degeneration, in degenerative spondylolisthesis grade I with a hypermobile segment and in dynamic lumbar stenosis. The combination of caudal fusion and cranial dynamic stabilization allows a better maintenance of lordosis with multiple level instrumentation and prevents adjacent segment degeneration. If pelvic incidence and sacral slope are high, L5-S1 should be fused because of elevated shear forces.

Focus on perioperative management of anticoagulants and antiplatelet agents in spine surgery

Perioperative management of anticoagulants and antiplatelet agents is based on a compromise between the risk of hemorrhage induced by maintaining (or substituting for) them and the risk of thrombosis if they are discontinued. The hemorrhage risk in major spinal surgery is clear (50-81% incidence of transfusion), and the incidence of postoperative symptomatic spinal hematoma varies between 0.4% and 0.2% depending on whether low-molecular-weight heparin (LMWH) is prescribed postoperatively. The French Health Authority, in 2008, published guidelines on the management of patients treated with vitamin K antagonists. Treatment may be stopped without preoperative replacement in certain cases of atrial fibrillation or venous thromboembolic disease; otherwise, preoperative replacement by curative dose unfractionated heparin (UFH) or LMWH is recommended, with withdrawal early enough to avoid peroperative bleeding. Postoperative care should take account of hemorrhagic risk following surgery. The management of patients treated with antiplatelets is delicate, as maintenance is preferable in most of the situations in which they are prescribed (bare or active stenting, or secondary prevention of myocardial infarction, stroke or peripheral ischemia), although they are liable to increase the risk of perioperative hemorrhage, especially when associated to antithrombotic prophylaxis. If surgery cannot be performed under treatment continuation, the interruption should be as short as possible. New guidelines are presently being drawn up under the auspices of the French Health Authority. In both types of treatment, the strategy should be jointly determined by surgeon, anesthesiologist and cardiologist, to optimize individualized care taking account of each party's requirements, with the patient in the central role. The selected strategy should be clearly stated in the patient's file.

LEVEL OF EVIDENCE

V.

Survivor of a traumatic atlanto-occipital dislocation

Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This injury occurs more frequently in children since they are anatomically predisposed (flat articulation between the occiput and the atlas, increased ligamentous laxity). The diagnosis should be suggested by severe neurological injury after high trauma but also post-traumatic cardiorespiratory deficit. There have been reports of atlanto-occipital dilocations without neurologic impairment. A radiographic examination must be performed and lateral cervical radiographs should be acquired. However, additional imaging with CT or MRI may be required to aid diagnosis of AOD in cases in which radiographic findings are equivocal. Once the diagnosis of AOD has been confirmed, an anatomical classification should be made according to the magnitude of displacement. Fatal lesions are of neurological and vascular origin and some authors advocate the systematic use of angiography. Consensus regarding the management of AOD in adults has been achieved. Occipito-cervical arthrodesis is the recommended treatment option. We advocate a two-stage surgery: the patient is initially fitted with a halo vest then occipitocervical fusion is performed. Surgical treatment should be combined with cardiorespiratory management. The emergency teams should get familiar with this injury since they will be increasingly confronted to it. Early recognition and standard appropriate management is essential to avoid delayed treatment and complications.

Intermediate clinical and radiological results of cervical TDR (Mobi-C) with up to 2 years of follow-up

The interest in cervical total disc replacement (TDR) as an alternative to the so-far gold standard in the surgical treatment of degenerative disc disease (DDD), e.g anterior cervical discectomy and fusion (ACDF), is growing very rapidly. Many authors have established the fact that ACDF may result in progressive degeneration in adjacent segments. On the contrary, but still theoretically, preservation of motion with TDR at the surgically treated level may potentially reduce the occurrence of adjacent-level degeneration (ALD). The authors report the intermediate results of an undergoing multicentre prospective study of TDR with Mobi-C prosthesis. The aim of the study was to assess the safety and efficacy of the device in the treatment of DDD and secondary to evaluate the radiological status of adjacent levels and the occurrence of ossifications, at 2-year follow-up (FU). 76 patients have performed their 2-year FU visit and have been analyzed clinically and radiologically. Clinical outcomes (NDI, VAS, SF-36) and ROM measurements were analyzed pre-operatively and at the different post-operative time-points. Complications and re-operations were also assessed. Occurrences of heterotopic ossifications (HOs) and of adjacent disc degeneration radiographic changes have been analyzed from 2-year FU X-rays. The mean NDI and VAS scores for arm and neck are reduced significantly at each post-operative time-point compared to pre-operative condition. Motion is preserved over the time at index levels (mean ROM = 9 degrees at 2 years) and 85.5% of the segments are mobile at 2 years. HOs are responsible for the fusion of 6/76 levels at 2 years. However, presence of HO does not alter the clinical outcomes. The occurrence rate of radiological signs of ALD is very low at 2 years (9.1%). There has been no subsidence, no expulsion and no sub-luxation of the implant. Finally, after 2 years, 91% of the patients assume that they would undergo the procedure again. These intermediate results of TDR with Mobi-C are very encouraging and seem to confirm the efficacy and the safety of the device. Regarding the preservation of the status of the adjacent levels, the results of this unconstrained device are encouraging, but longer FU studies are needed to prove it.

Sagittal alignment correction of the thoracolumbar junction in idiopathic scoliosis by in situ bending technique

A long thoracolumbar sagittal rectitude is sometimes present in adolescent idiopathic scoliosis. The purpose of this study was to identify typical patterns, by comparing frontal plane deformities and vertebral rotation leading to this rectitude. Surgical thoracolumbar alignment correction by three-dimensional in situ bending of rods was then analyzed. Pre- and postoperative radiographs of 24 patients with scoliosis (36-104 degrees) were reviewed using Spineview software. Frontal curves and levels of sagittal rectitude were determined. Thoracic kyphosis, lumbar lordosis, sacral slope, pelvic incidence, pelvic tilt, T9 and T1 tilt were measured. Vertebral rotation was measured by computed tomography, Perdriolle's, Nash and Moe's methods. The intervertebral mobility of the rectitude was analyzed on side bending radiographs. Three patterns leading to sagittal rectitude were identified: 11 main thoracic curves (Lenke 1, King 3) with cranial prolongation of the physiological thoracolumbar junction (T7T12) and maximal vertebral rotation above this zone, 13 double major or thoracolumbar curves (Lenke 3 or 5, King 1 or 2) with cranial and caudal prolongation (T9L3) and maximal rotation above and below, 1 lumbar curve (Lenke 5) with caudal rectitude (T12L4) and maximal rotation at L1. There was no relationship between intervertebral mobility and rectitude. Postoperatively, this zone of rectitude disappeared in 17 out of 24 patients after anterior release followed by posterior instrumentation using the in situ bending technique. In situ bending realizes a stepwise correction of the three-dimensional deformity at different levels. An accurate preoperative analysis is mandatory to achieve an adequate sagittal balance, frontal curve correction and vertebral derotation simultaneously. The determined patterns of thoracolumbar rectitude are helpful to plan surgical correction accurately.

Percutaneous vertebroplasty in a broken vertebral titanium implant (titanium mesh cage)

We report the case of a percutaneous consolidation of a broken vertebral implant (Surgical Titanium Mesh Implants; DePuy Spine, Raynham, MA, USA) by vertebroplasty. Four years after anterior spondylectomy with cage implantation and stabilization with posterior instrumentation, the patient was admitted for excruciating back pain. Radiographs showed fracture of the cage, screw, and rod. An anterior surgical approach was deemed difficult and a percutaneous injection of polymethyl methacrylate into the cage was performed following posterior instrumentation replacement. This seems to be an interesting alternative to the classical anterior surgical approach, which is often difficult in postoperative conditions.

[Pedicle closing-wedge osteotomy for the treatment of fixed sagittal imbalance]

PURPOSE OF THE STUDY

The aim of this study was to analyze x-ray results in patients who underwent pedicle subtraction osteotomy for complex deformations (flat back, kyphosis) leading to fixed sagittal imbalance.

MATERIAL AND METHODS

Thirty-four patients underwent surgery between 1996 and March 2003 in two centers, the orthopedic surgery unit devoted to spinal surgery and sports traumatology at the Strasbourg University Hospitals and the spinal surgery unit at the Chenove Clinic (Dijon). The series included 20 women and 14 men, mean age 46.5 years (range 14-74 years) treated for: postoperative flat back (n = 19), kyphoscoliosis (n = 6), ankylosing spondylarthritis (n = 5), and malunion (n = 4). After careful planning to achieve the necessary degree of correction, the patient was installed on a Cotrel table with a stable support enabling limited blood loss and facilitated reduction maneuvers via elevation of the lower limbs. The technique started by resection of the posterior arch, the transverse processes, and the pedicles, followed by partial resection of the body with a chisel under fluoroscopic control. The closure was achieved by in situ reduction with compressive rotation. Adjacent discs were then evaluated to search for any opening which could be filled by an anterior graft to complete the stabilization. The osteosynthesis used 2-, 4-, and 6-rod assemblies. The 6-rod assemblies enabled anchoring the fixation above and below before the osteotomy. Two prebent rods completed the assembly at reduction after osteotomy. Weight-bearing started on day 4. A protective corset was worn for three months by 19 patients. The patients resumed their occupational activities on average 6.73 months postoperatively without change in activity for 63%. Overall satisfaction was close to 90% excellent outcome.

RESULTS

All clinical results were analyzed with the Profil software of Surgiview. X-ray data were analyzed with Spineview. A self-administered clinical questionnaire was used to evaluate pain, result of the operation, and the impact on the patient's body image. On average, the wedge osteotomy measured 28.9 degrees for correction of lumbar lordosis by 31.5 degrees with a maximum of 65 degrees. The misalignment at C7 was reduced from 51 mm to 2 mm. At the pelvic level, version improved 16 degrees, sacral slope 8 degrees. There were four dura mater breaches which had to be sutured, but with no clinical consequence (one progression to meningocele). Mean intraoperative blood loss was 1400 cc (300-4500cc) for a mean operative time of 260 minutes (165-450 min). There were two early infections at day 15 postop which resolved with antibiotics. Four patients developed resolutive sciatica (n = 2) or cruralgia (n = 2) during the following months. The short-term follow-up revealed eight non-unions (25%) with rupture of osteosynthesis material and loss of correction. The opening in the adjacent discs and the insufficient posterior closure explained this mechanical complication.

CONCLUSION

Pedicle subtraction osteotomy is an original operative technique reserved for specialized centers. A well-experienced team is needed to control the risks involved. Sagittal balance should be one of the important goals for modern spinal surgery.

Finite element simulation of spinal deformities correction byin situcontouring technique

Biomechanical models have been proposed in order to simulate the surgical correction of spinal deformities. With these models, different surgical correction techniques have been examined: distraction and rod rotation. The purpose of this study was to simulate another surgical correction technique: the in situ contouring technique. In this way, a comprehensive three-dimensional Finite Element (FE) model with patient-specific geometry and patient-specific mechanical properties was used. The simulation of the surgery took into account elasto-plastic behavior of the rod and multiple moments loading and unloading representing the surgical maneuvers. The simulations of two clinical cases of hyperkyphosis and scoliosis were coherent with the surgeon's experience. Moreover, the results of simulation were compared to post-operative 3D measurements. The mean differences were under 5 degrees for vertebral rotations and 5 mm for spinal lines. These simulations open the way for future predictive tools for surgical planning.

Validation of the relative 3D orientation of vertebrae reconstructed by bi-planar radiography

The three dimensional (3D) reconstruction of the spine can be obtained by stereoradiographic techniques. To be safely used on a routine clinics basis, stereoradiography must provide both accurate vertebral shape and coherent position. Although the accuracy of the reconstructed morphology of the vertebrae is well documented, only few authors studied the accuracy of the vertebral orientation. Therefore, this paper focuses on the evaluation of the orientation accuracy of the reconstructed vertebrae (obtained by non-stereo corresponding point technique) considering either a 178 point vertebral model or a 6 point vertebral model (previously proposed in the literature). Five dried vertebrae were fixed on holders containing four markers each. The 3D reconstruction of both vertebrae and markers were obtained by stereoradiographic techniques. Using least square method matching from one position to another, the relative orientation was computed for the vertebral models (6 or 178 points) and the four markers. These vertebral and holder orientations were compared (considering the holder's one as reference). The repeatability of these relative orientations (vertebrae and holders) was also evaluated. The mean (RMS) orientation error of 178 point vertebral model was 0.6 degrees (0.8 degrees ), for lateral rotation, 0.7 degrees (1.0 degrees ) for sagittal rotation and 1.4 degrees (1.9 degrees ) for axial rotation. The intra-observer repeatability was 0.5 degrees (0.7 degrees ) for lateral rotation, 0.7 degrees (0.8 degrees ) for sagittal rotation and 0.9 degrees (1.2 degrees ) for axial rotation. The orientation was found more accurate and precise when using the 178 point vertebral model than when using the basic 6 point vertebral model. The relative orientation (in post-operative follow-up with respect to the pre-operative examination) of the vertebrae of one scoliotic patient was performed as an example of clinical application. The stereoradiographic method is a reliable 3D quantitative tool to assess the spine deformity, that can be used in clinics for the follow-up of scoliotic patients.

Long term follow-up of two sibs with an autosomal recessive form of chrondrodysplasia punctata and epilepsy

Long term follow-up of two sibs with an autosomal recessive form of chrondrodysplasia punctata and epilepsy: A variety of osteodysplasias are referred to with the term chondrodysplasia punctata (CDP). Here we report on two sibs, a boy and a girl, with probable autosomal recessive form of CDP and epilepsy followed-up for 30 and 19 years, respectively. Family history was unremarkable but for consanguinity. Pregnancies and deliveries were uneventful. At birth, length was 46 (-3SD) and 45 (-4SD) cm, respectively. Craniofacial dysmorphism was noted: severe nasal hypoplasia, flat face, hypertelorism, a low nasal bridge, short stature. Skeletal abnormalities included epiphyseal stippling in the thoracic spine, bilateral proximal and distal humeri, femur, tibia and bilateral carpal and tarsal bones. The boy had a hemivertebrae T12, with absence of a rib. After the age of 6 years facial dysmorphism had improved. Final height was 154 cm (-3SD) in the boy and 158 cm (-0,5SD) in the girl. The boy was operated on for scoliosis. Both sibs had club feet, the girl had also genu valgum. IQ was evaluated to be 55 in the girl and 83 in the boy. The first non febrile generalized seizure appeared in the boy when he was 11 months of age, and in the girl when she was 25 months of age. Both had many other seizures and were taking antiepileptics. EEG were abnormal. Karyotypes were normal. Extensive screening for metabolic disorders was normal. Acquired in utero CDP were excluded. We suggest the sibs described in this report have yet another provisionally unique possibly autosomal recessive syndrome, with CDP and epilepsy as phenotypic traits.

Explicit calibration method and specific device designed for stereoradiography

The three-dimensional geometry of the human spine is noteworthy information that can be obtained by stereoradiographic methods. These methods are based on the identification of anatomical structures in several views which are obtained by rotation of a patient standing on a turntable. Calibration algorithms for computer vision or photogrammetry are well documented, but they generally yield calibration devices which are cumbersome for the use in clinical stereoradiography. This paper presents a calibration method adapted to a two-view stereoradiography calibration (frontal and lateral incidences) and based on a simplified geometric modeling of the radiological environment. The a priori knowledge yields four calibration equations related to the vertical and horizontal planes of both views, leading to a specific calibration procedure and device. Moreover this device is attached to the stereoradiographic system (directly integrated on the turntable) in order to facilitate clinical applications. A validation was performed on 26 dried lumbar vertebrae in order to evaluate clinical situation. The mean accuracy of the stereoradiographic reconstruction was 1.2mm.

Pre and post 3D modeling of scoliotic patients operated with in situ contouring technique

A three-dimensional segmental analysis was performed on the stereoradiographic reconstructions of ten right thoracic scoliotic patients. From the quantitative model of the spine and pelvis, the vertebral and intervertebral orientations were computed pre and post operatively. These orientations allow to determine the apical and junctional zones of the high thoracic, thoracic and lumbar curves. The apical zone corresponds to the maximum of vertebral axial rotation. Pre operatively, the tendency was T7 for the thoracic transverse apex with 20 AE of axial rotation. The junctional zone corresponds to the maximum of vertebral lateral rotation and the maximum of intervertebral axial rotation. The tendency was T5 and T12 for the junctional vertebrae of the thoracic curve with, at both levels, 30 AE of vertebral lateral rotation and 10 AE of intervertebral axial rotation. The surgical correction obtained by in situ contouring technique was evaluated through these 3D orientations. The vertebral axial rotation at the high thoracic, thoracic and lumbar apex was corrected with respectively 52%, 60% and 60%.

[Results of lumbar and lumbosacral fusion: clinical and radiological correlations in 113 cases reviewed at 3.8 years]

PURPOSE OF THE STUDY

Spinal fusion requires the use of hardware for reduction and stabilization. We present the clinical and radiological behavior of a population of patients with lumbar and lumbosacral spinal fusion.

MATERIALS AND METHODS

Between 1990 and 1992, 113 patients were operated for lumbar and lumbosacral fusion. Mean age of the population was 43 years and mean follow-up was 3.8 years. Most of the fusions were L4-S1 fusions. 56% of the patients had a previous surgery. Thirteen patients in the series were reoperated and analyzed separately. In the majority of the cases, the indication for surgery was back pain with or without leg pain. Diagnoses were: spondylolisthesis, discopathy, scoliosis, and pseudoarthrosis. The spine was fused and reduced using two lordotic rods. Peroperative and postoperative lordosis were calculated on X-rays. Clinical results were analyzed with the Beaujon-Lassale score.

RESULTS

Mean improvement was significantly better for spondylolisthesis than for other pathologies (85.6% versus 77.1%). Returning to work was possible for 85.5% of those with improvement and was not possible for 69.8%. The gain achieved in lordosis at surgery was lost at last follow-up. The lordosis of the construct appeared to protect against the development of discopathies above and below the construct. Discopathis led to a poor score. The rate of non-union was 7.9%, the rate of repeated surgery 6.1% and the rate of hardware removal 23.8%. At last follow-up, improvement was achieved in 45.6% of the 13 patients of the series who had repeat surgery.

DISCUSSION

The results in our series are similar to those reported by others. Lumbar lordosis is an important factor: if lost, more interbody fusions may be subsequently required. Diagnosis of non-union is difficult and reoperation is the only sure manner to prove it by applying distraction-compression manoeuvres on the screws. All non-unions presented were symptomatic; incidence in the series was thus probably higher. Non-union and reoperation with a longer fusion are perhaps correlated with insufficient elasticity in the osteosynthesis. Optimal rod elasticity is a factor which remains to be defined.

CONCLUSION

Clinical results of lumbar and lumbosacral fusions are not unsatisfactory, but in our series almost one patient out of three had to be reoperated. One of the reasons for so many reoperations is certainly hardware rigidity. Hardware was not removed without testing the fusion as this is the only means of sure diagnosis of non-union. Reoperation should not be considered a failure in this difficult surgery of back pain which requires long-term surgical follow-up.

Percutaneous laser photocoagulation of spinal osteoid osteomas under CT guidance

BACKGROUND AND PURPOSE

Spinal osteoid osteomas are rare; when they occur, they are usually treated by surgical or percutaneous excision. The aim of percutaneous interstitial laser photocoagulation (ILP) of osteoid osteomas under CT guidance is thermal destruction of the nidus using low-power laser energy, thus precluding bone resection and open surgery.

METHODS

Three cases of spinal osteoid osteomas were treated with percutaneous ILP of the nidus. Under CT guidance, the needle was positioned in the center of the nidus, at least 8 mm from neurologic structures. Using a high-power semiconductor diode laser (805 nm) with a 400-microm optical fiber, we delivered 600 to 800 joules to the nidus, depending on its size. The procedure was performed with the patient under neuroleptanalgesia and required overnight hospitalization.

RESULTS

Complete pain relief was obtained in all three patients within 24 hours of the procedure, and no major complications were incurred. Follow-up ranged from 20 months to 60 months.

CONCLUSION

Percutaneous ILP of spinal osteoid osteoma is a promising, simple, precise, and minimally invasive technique and may be an alternative to traditional surgical and percutaneous ablations.

[Enlargement in managment of lumbar spinal stenosis]

Lumbar stenosis has been well discussed recently, especially at the 64th French Orthopaedic Society (SOFCOT: July 1989). The results of different surgical treatments were considered as good, but the indications for surgical treatment were not clear cut. Laminectomy is not the only treatment of spinal stenosis. Laminectomy is an approach with its own rate of complications (dural tear, fibrosis, instability... ).Eight years ago, J. Sénégas described what he called the "recalibrage" (enlargement). His feeling was that, in the spinal canal, we can find two different AP diameters. The first one is a fixed constitutional AP diameter (FCAPD) at the cephalic part of the lamina. The second one is a mobile constitutional AP diameter (MCAPD) marked by the disc and the ligamentum flavum. This diameter is maximal in flexion, minimal in extension. The nerve root proceeds through the lateral part of the canal: first above, between the disc and the superior articular process, then below, in the lateral recess bordered by the pedicle, the vertebral body and the posterior articulation. With the degenerative change the disc space becomes shorter, the superior articular process is worn out with osteophytes. These degenerative events are complicated by inter vertebral instability increasing the stenosis. The idea of the "recalibrage" is to remove only the upper part of the lamina with the ligamentum flavum and to cut the hypertrophied anterior part of the articular process from inside. If needed the disc and other osteophytes are removed. The surgery is finished with a ligamentoplasty reducing the flexion and preventing the extension by a posterior wedge.Our experience in spine surgery especially in scoliosis surgery, showed us that it was possible to cure a radicular compression without opening the canal. The compression is then lifted by the 3D reduction and restoration of an anatomy as normal as possible. Lumbar stenosis is the consequence of a degenerative process. Indeed, hip flexion, obesity or quite simply overuse, involve an increase in the lumbar lordosis. The posterior articulations are worn out and the disc gets damaged by shear forces. The disc space becomes shorter with a bulging disc, and the inferior articular process of the superior vertebra goes down. This is responsible of a loss of lordosis. For restoring the sagittal balance the patient needs more extension of the spine. Above and below the considered level the degenerative disease carries on extending to the whole spine. At the level considered, because of local extension, the inferior facet moves forward, the disc bulges, the ligamentum flavum is shortened and the stenosis is increased. This situation is improved by local kyphosis: the inferior facet moves backward, the disc and the ligamentum flavum are stretched with a quite normal posterior disc height and most often there is no more stenosis. Myelograms show this very well with a quite normal appearance lying, clear compression standing, worse in extension and improved, indeed disappeared in flexion. CT scan and MRI don't show that because they are done lying. The expression of the clinical situation is the same, mute lying and maximum standing with restriction of walking. For us lumbar stenosis is operated with lumbar reconstruction without opening the canal. The patient is in moderate kyphosis on the operating table. Pedicle screws rotated to match a bent rod allow reduction of the spine. The posterior disc height is respected and not distracted, and the anterior part of the disc is stretched in lordosis. The inferior facet is cut for the arthrodesis and no longer compresses the dura. The canal is well enlarged and the lumbar segment in lordosis is the best protection of the adjacent levels at follow-up. This behaviour responds to the same analysis as the ≪recalibrage≫ (enlargement). The mobile segment is damaged by the degenerative disease, the stenosis is a consequence of this damage. It's logical to treat the instability and to restore the normal static anatomy; thus bone resection is not necessary. At the present time all the lumbar stenoses with reduction in flexion are instrumented with spinal reduction and arthrodesis without opening the canal. The laminoarthrectomy and the enlargement are done when there is a fixed arthrosis which is rare in our practice and found in an older population. The follow-up shows a loss of reduction in some cases after reduction-instrumentation-arthrodesis and poses the question of an interbody fusion. We don't open the canal only for fusion (PLIF) if this is not necessary for the treatment of the stenosis. We think that, in such a situation, the future is ALIF with endoscopical approach. The problem is to determine which disc demanding this anterior fusion, is able to regenerate or not.

Epithelioid sarcoma of the spine: a case report

STUDY DESIGN

This case report illustrates a patient presenting with sciatica and diagnosed with epithelioid sarcoma involving the spine.

OBJECTIVES

The treatment of this patient involved multiple mass resections and decompressions of the spinal canal. Radio- and chemotherapy were applied once a clear diagnosis was obtained.

SUMMARY OF BACKGROUND DATA

Epithelioid sarcoma is a rare tumor mainly arising in the extremities. Confusion with a benign inflammatory process are possible. Treatment after histologic diagnosis involves wide resection. To our knowledge, this report represents the first case of epithelioid sarcoma involving the spine.

METHODS

After initial discectomy, recurrent scarring and mass formation required multiple decompression procedures and fusion. The initial pathology revealed inflammatory reaction on fibrosis. In a later procedure, the histologic diagnosis of epithelioid sarcoma was made. Radiotherapy and chemotherapy were begun immediately.

RESULTS

Despite aggressive resections, radiotherapy, and chemotherapy, the patient died 3 months after the last surgical procedure.

CONCLUSION

Spinal epithelioid sarcoma can be mistaken for a benign inflammatory process. After a histologic diagnosis, aggressive wide resection is necessary. Multiple recurrences are documented with this tumor in other sites. Prognosis in trunk involvement is less favorable than involvement of the extremities. The role of adjuvant radio- and chemotherapy is unclear for spinal involvement.

[Intra-operative fractures: analysis]

51 fractures during total hip arthroplasty were studied. Fractures appeared to be predisposed to several factors: osteoporosis (20%), revision (32%), neck fractures (30%), ankylosis of the hip (16%). The risk seemed greater with non cemented prostheses. Consolidation was obtained in 60.6 days : no statistical difference was found with respect to the type of fracture or treatment.Such fractures do not seem to jeopardize the stability of the femoral component in the long-term.

[Cotrel-Dubousset instrumentation in the treatment of scoliosis]

The authors describe the operative principles of the C.D. device reviewing implantable material (rods and hooks, screws and transverse system). The principles of this surgical approach (2 rods) which offers the possible distraction and contraction where necessary, are described. Good derotation is achieved and a strong and stable square support device enabling the patient to be got out of bed rapidly without any need for post-operative support. The post-operative care is extremely easy and a rapid return to school activity is possible.