Posterior Wall Of Vertebral Body Research Articles

A novel uniplanar clamp-hinge correction system for vertebral column resection of severe angular kyphosis: an experimental study using a sawbone model.

To introduce a novel uniplanar clamp-hinge (Uni-CH) correction system designed for vertebral column resection (VCR) of severe angular kyphosis and test its efficacy using a sawbone simulating model. The Uni-CH was introduced and its functionality was demonstrated on a sawbone model simulating severe angular kyphosis. An 83° thoracolumbar angular kyphosis with the apex at T11 was simulated in the sawbone spine model. The deformity was then corrected using the Uni-CH to identify the optimal hinge position for VCR reduction of severe angular kyphosis. The thoracolumbar angular kyphosis, initially measuring a mean of 82.7 ± 0.5°, was corrected to 0°, achieving a 100% correction rate. The optimal hinge position was identified to be at the level of the posterior vertebral body wall (PVBW), which allowed for the maintenance of the spinal cord with a slight shortening of 3%. In contrast, hinge positions located more posteriorly to the PVBW resulted in a greater 42% lengthening of the spinal cord, while positions located more anteriorly led to a greater 27% shortening of the spinal cord. The Uni-CH proves its efficacy in providing consistent stability to the spinal segments and acts as an adjustable and controllable hinge for VCR correction of severe angular kyphosis in the sawbone model. Placing the hinge pivot at the level of the PVBW preserves the spinal cord, preventing excessive shortening or lengthening during VCR reduction of severe angular kyphosis.

Reverse Cortical Sign in Lumbar Burst Fracture.

"Reverse cortical sign" is a rare entity described in lumbar burst fracture that corresponds to the fracture fragment of the posterior wall of vertebral body, which has rotated 180 degrees with the cortical surface facing anteriorly and the cancellous surface facing posteriorly in the canal. Identifying this sign is crucial in deciding the line of management as it is a contraindication for ligamentotaxis. The advent of computed tomography scans with axial and sagittal reconstruction has allowed us to better describe these rare entities. We present a lumbar burst fracture with a reverse cortical sign describing its appearance in axial computed tomography scans, sagittal reconstruction, and magnetic resonance imaging.

Morphological features of basivertebral foramen among different age groups: Recognition in spine.

Basivertebral foramen (BF) is a vessel and nerve passage in the posterior wall of vertebral body (VB). Our goal was to report BF's morphological characteristics in different age groups of mainland Chinese adults and to evaluate the relationship between BF's morphology and factors such as age, gender, heavy work, size and level of VB. We enrolled 300 adults among persons who came to our hospital for health examination. We measured BFs and VBs' parameters on T1 weighted sagittal lumbar spine MR images. We also assessed following potential predictors: gender, body height, body weight, body mass index, alcohol use, habits of smoking and drinking, type of work (physical work or non-physical work). A stepwise multivariate linear regression analysis was conducted to identify predictors of BF's height. People above 60 have significantly bigger BFHr than those in young adulthood and in the middle ages at all five levels, while they have shallowest BFs, especially at L3. Multiple linear regression resulted in a formula that accounted for 30.1% of the variability in the height of basivertebral foramen. Significant predictors included: gender, age, level, vertebral height and heavy work. Age is the highest weight in all factors on the height of BF. BF is closer to the upper endplate. The BF was relatively higher and deeper in the female lumbar spine. Heavywork results in lower BF. Last but not the least, as we supposed, BF gets shallower and higher compare to VB with age. Prognostic level III. See instructions for authors for a complete description of levels of evidence.

The role of Vertebral Augmentation Procedures in the management of vertebral compression fractures secondary to multiple myeloma.

Multiple myeloma (MM) is a systemic disorder characterised by proliferation of B-lymphocytes and plasma cells in the bone marrow. The primary aims of the management of spinal lesions in MM are pain control and fracture stabilisation. Vertebral augmentation procedures (VAP) can be subdivided into percutaneous vertebroplasty (VP) and balloon kyphoplasty (BKP). BKP involves the placement of orthopaedic balloons into the fractured vertebral body, creating a void into which polymethylmethacrylate bone cement is injected. This review outlines the management of spinal lesions in patients with MM, with a focus on the comparative risks and efficacy of vertebroplasty (VP) and balloon kyphoplasty (BKP). Soft tissue masses in MM are highly radiosensitive. Bisphosphonates and newer oncological therapies have decreased the indications for palliative radiotherapy, while spinal bracing can be utilised in selected cases to provide stability. BKP and VP provide equivalent long term pain control after MM vertebral compression fractures (VCF). BKP is superior to non-operative management and VP for restoration of vertebral body height and prevention of segmental kyphosis. Current evidence suggests a greater degree of correction of kyphotic deformity and restoration of mid vertebral height (MVH) with BKP when compared with VP. The literature supports the use of BKP even in the presence of posterior vertebral body wall (PVBW) fractures, a group previously considered a contraindication to VAP. Superior functional outcomes have been reported in patients undergoing early versus delayed BKP (<6-8weeks). Current evidence supports a lower risk of cement extrusion with BKP than with VP, but serious complications following VAP are rare. MM spinal pathology should be managed in a multidisciplinary setting. Surgical decompression and instrumentation are rarely indicated, due to the radio-sensitivity of soft tissue lesions in MM. BKP is a safe and effective procedure for VCF secondary to MM.

Lateral-Opening Injection Tool Used in Percutaneous Vertebroplasty to Treat Asymptomatic Osteoporotic Vertebral Burst Fractures: A Retrospective Study.

The adequate management of asymptomatic osteoporotic vertebral burst fractures (OVBFs) was still controversial. Percutaneous vertebroplasty (PVP) could achieve quick recovery with minor trauma, but there were certain safety problems by traditional bone cement injection method. Thus, the aim of this study was to assess the efficacy of lateral-opening injection tool used in PVP treating patients with asymptomatic OVBFs. This was a retrospective study of OVBFs treated in our institute from March 2016 to March 2020. A total of 66 patients (mean age 72.10 ± 7.98 years, with 21 men and 45 women) who were diagnosed with acute asymptomatic OVBFs with mild spinal canal compromise were treated with PVP by using a lateral-opening injection tool. Two puncture needles were simultaneously placed transpedicularly in the fractured vertebra, and the inner core was removed, and the lateral-opening injection tool was inserted. The adjustment of lateral hole was to improve the distribution height of bone cement and avoid the entry of bone cement into the posterior wall of vertebral body. Related clinical outcomes and images were assessed, including back pain (visual analog scale [VAS]), vertebral height ratio (fractured vertebral height/average adjacent nonfractured vertebral height), kyphosis Cobb angle, union of the fractured vertebral posterior wall, distribution of bone cement, surgical data, and complications. The average follow-up time of all cases was 21.23 ± 9.35months. The mean amount of bone cement was 3.28 ± 0.35 ml in the vertebrae and the mean operative time was 34.02 ± 5.23 min. There were 60 cases of bone cement that contacted the upper and lower endplates on at least one side. There was no cement leakage into the spinal canal or fracture displacement of the posterior wall of the vertebral body in all cases. The VAS scores were 3.78 ± 0.42 at 1 day postoperatively and 0.53 ± 0.40 at the last follow-up, significantly lower than 8.40 ± 0.48 preoperatively (p < 0.05). The average height ratio of anterior, middle, and posterior vertebral body after operation increased compared with that pre-operation (p < 0.05), and the postoperative kyphosis angle decreased (p < 0.05). At 6 months follow-up, there was no significant height loss of the vertebral body. Computed tomography examination 3 months postoperatively showed that the fracture of posterior vertebral wall healed well in all cases. There were seven cases of bone cement leakage without clinical symptoms and two adjacent vertebral fractures caused by falling. There were no cases of deep vein embolism, lower limb muscle atrophy, pneumonia, decubitus. The lateral opening tool can be safely and effectively used in the PVP treatment on asymptomatic OVBFs with mild spinal canal compromise.

Clinical application of an improved classification system of Kümmell's disease

To report an improved classification system of Kümmell's disease and its clinical application. Based on CT and MRI, an improved classification system of Kümmell's disease was proposed in terms of the integrity of sagittal endplate, the integrity of posterior wall of vertebral body, and the degree of vertebral compression. Between January 2011 and March 2018, the improved classification system was used to evaluate and guide the treatment of 78 patients with Kümmell's disease. There were 13 males and 65 females. The mean age was 69.1 years (range, 54-85 years). The mean disease duration was 4.0 months (range, 1-8 months). The mean T value of bone mineral density was -3.66 (range, -3.86- -3.34).The fractures located at thoracic vertebrae in 47 cases and lumbar vertebrae in 31 cases. According to the modified classification system of Kümmell's disease, there were 11 cases of type A1, 13 cases of type A2, 2 cases of type A3, 10 cases of type B1, 18 cases of type B2, 4 cases of type B3, 4 cases of type C1, 5 cases of type C2, and 11 cases of type C3. According to the classification results, the patients of types A and B were treated with percutaneous kyphoplasty (PKP), while the patients of type C were treated with PKP or intra- vertebral fixation according to the degree of vertebral reduction. Visual analogue scale (VAS) score and Oswestry Disability Index (ODI) were used to evaluate clinical efficacy. The heights of the anterior, middle, and posterior edges of the vertebrae and the Cobb angle were measured to evaluate the reduction of the injured vertebrae and the improvement of kyphosis deformity. The complications were recorded. The statistical analysis showed that the improved classification system has good consistency. All patients were followed up 12-36 months (mean, 24.3 months). The heights of anterior, middle, and posterior edges of the vertebrae, Cobb angle, VAS score, and ODI of all types of patients at last follow-up showed significant differences when compared with those before operation ( P<0.05). After operation, 4 patients of type A2 had different degree of vertebral height loss; 2 patients of type B2, 3 patients of type C1, and 2 patients of type C2 developed asymptomatic bone cement leakage during PKP; 2 patients of type B3 and 3 patients of type C2 underwent percutaneous internal fixation and vertebral augmentation due to bone cement loosening. The modified classification system of Kümmell's disease can be used to guide treatment of Kümmell's disease, but the number of clinical application cases is limited, and further application and observation are needed.

Basivertebral foramina of true vertebrae: morphometry, topography and clinical considerations.

Basivertebral foramina (BVF) are openings of the posterior wall of vertebral body (VB) that lead to basivertebral canals (BVC), where homonymous neurovascular bundle courses. BVFand BVC are implicated with spinal fractures, vertebral augmentation and basivertebral nerve radiofrequency ablation. Despite their essential clinical impact, knowledge of BVF precise anatomy is scarce. The current study describes in detail the BVF typical morphologicaland topographical anatomy, morphometry and variants. In total, 1561 dried true vertebrae of 70 Greek spines of known gender and age were examined. BVF number, location, shape and size (in foramina > 1mm), BVF distance from VB rims and pedicles, as well as VB morphometry (diameters, heights and distance between pedicles) were studied. Ten spines were re-examined by computed tomography and BVC depth and shape were recorded. Correlations and differences were statistically analyzed. C1 lack BVF (3.4%). One BVF was found in 45.1%, two in 36.9%, three in 3.8% and four BVF in 0.6%. Multiple small (< 1mm) foramina were observed in 10.1%. Asymmetry was detected in 12.3%. C2 and T10-L1 presented typical pattern, whereas C3 and T2 had the greatest variability. BVF were significantly closer to the upper rim in C2 and T10-L4 and to the lower rim in C7-T4, T6-T8 and L5. The mean BVC depth was 12-21.8% of the VB anteroposterior diameter. BVF number, shape, size and topography are described, in detail, per vertebral level. The provided morphological classification and the created cumulative BVF topographic graphs should assist in clinical practice and surgery.

Risk of intervertebral disc joint puncture during lumbar puncture

ObjectivePenetration of intervertebral disc joint during lumbar puncture might be unnoticed during procedure. However, accelerated degeneration of the disc joint is a long-term consequence of inadvertent penetration. In this paper, we aimed to demonstrate and evaluate the risk of disc puncture during standard lumbar puncture. Patients and Methods50 human cadavers were used in this study. Disc puncture risk was assessed by using worst case scenario model. Lumbar puncture was performed in a standard fashion using midline route at L3−4, L4−5 and L5-S1 levels. The needle was advanced until it hit resistance from the bone. Lateral X-ray was used to visualize the needle position. Needle ended up in two possible locations - posterior vertebral body wall and intervertebral disc space. ResultsThe probability of puncturing the joint was 20 % for L3−4, 38 % for L4−5, 16 % for L5-S1. Total probability of disc penetration was 25 %. Statistical analysis revealed significantly increased risk for performing LP at L4−5 level in comparison with L5-S1 (p = 0.023). ConclusionLumbar puncture carries significant risk of intervertebral disc penetration. This complication is not realized during the procedure and lead to accelerated joint degeneration.

P111. Simulated corrections of cervical deformity using in-construct measures demonstrate that insufficient corrections result in DJK

BACKGROUND CONTEXT Distal junctional kyphosis (DJK) is a major concern following cervical deformity (CD) correction, leading to failed realignment and revision surgery. Undercorrection may be the major factor associated with DJK, however it is difficult to assess because the DJK erodes the correction and worsens traditional measures like cSVA. In-construct measures have been proposed that measure alignment within the fusion separate from the DJK and subjacent compensation. PURPOSE To simulate cervical deformity corrections using surgical planning software to determine if undercorrection results in DJK. STUDY DESIGN/SETTING Retrospective analysis of a prospective, multicenter CD database. PATIENT SAMPLE A total of 69 CD patients. OUTCOME MEASURES Radiographic measures: C2 plumblines, in-construct measures and DJK angle change. METHODS A prospective database of operative CD patients was analyzed for severe DJK (kyphosis change>20° in LIV to LIV-2) and traditional DJK (change>10°). C2LIV-Tilt (angle of a line from the centroid of C2 to the centroid of the lower instrumented vertebra and a line along the posterior vertebral body wall of the LIV) was measured postoperatively and the correction was simulated in the preoperative X-ray to match the C2LIV-Tilt using planning software. Linear regression analysis using C2 pelvic angle (CPA) and Pelvic Tilt (PT) determined the simulated PT to match the virtual CPA. SVA measures were compared in patients with severe and traditional DJK and no DJK. Linear regression analysis was used to determine the C2-T4 and C2-T10 Tilts that correspond to DJK=10° and cSVA=4cm. RESULTS A total of 69 CD patients (mean age 61, 60% female) were included. Severe and traditional DJK occurred in 11 (16%) and 22 (32%) patients; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and traditional DJK pts had worse alignments compared to no DJK pts: cSVA (42.5 vs 33.0 vs 23.4mm, p .57, p CONCLUSIONS Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of CD correction. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

A limited unilateral transpedicular approach for anterior decompression of the thoracolumbar spinal cord in elderly and high-risk patients.

Background:Surgical treatment for elderly patients with thoracolumbar (TL) kyphosis and spinal cord (SC) compression presents significant challenges due to compression location, the amount of deformity, and patient's medical status might not permit full correction of the deformity. In this series, we present a surgical approach that provides adequate decompression without the risks associated with a pedicle subtraction osteotomy/posterior vertebral column resection or an anterior corpectomy.Methods:Three patients presented with TL kyphosis and progressive neurologic symptoms. All had acute weakness; none were ambulatory. SC was compressed over the apex of kyphosis, and for some, there was spinal stenosis at the proximal junction of the TL spine. The surgical technique involved unilateral resection of the pars, pedicles, the posterior one-third of the lateral wall of the vertebral body, decancellation of the impinging kyphus, and finally resection of the posterior vertebral body wall compressing the SC followed by instrumentation and fusion two levels above and below the fused segments.Results:All patients survived the procedure and left the hospital after 10–22 days. Estimated blood loss was 653 ml. No deep infections occurred. One patient developed acute tubular necrosis but recovered fully. The other two showed improvement of one Frankel grade and were independent in the final follow-up. One patient developed acute tubular necrosis but recovered fully yet his neurologic status was unchaged. The other two showed improvement of one Frankel grade and were independent in the final follow-up.Conclusion:The procedure described presents a compromise that fits the more elderly patient that might not be able to tolerate major deformity correction and at the same time provides similar results in the short and medium term to more extensive procedures.

44 - Is balloon kyphoplasty safe and effective for cancer-related vertebral compression fractures with posterior vertebral body wall defects?

44 - Is balloon kyphoplasty safe and effective for cancer-related vertebral compression fractures with posterior vertebral body wall defects?

Is balloon kyphoplasty safe and effective for cancer-related vertebral compression fractures with posterior vertebral body wall defects?

Balloon kyphoplasty (BKP) is a percutaneous treatment for cancer-related vertebral compression fractures (VCF). Posterior vertebral body wall (PVBW) involvement is considered a contraindication for BKP. This study assesses whether BKP is safe and effective for cancer-related VCFs involving the PVBW. This study analyzed data on 158 patients with 228 cancer-related VCFs who underwent BKP. One hundred and twelve patients had VCFs with PVBW defects, and 46 had VCFs with no PVBW defect. Outcomes were assessed preoperatively and at 3 months. In the PVBW defect group, mean pain score decreased from 7.5 to 3.6 (P < 0.001), EQ5D increased from 0.39 to 0.48 and Oswestry Disability Index (ODI) decreased from 50 to 42. Cement leaks occurred in 31%. In the PVBW intact group, mean pain decreased from 7.3 to 3.3 (P < 0.001), EQ5D increased from 0.35 to 0.48 (P < 0.001), and ODI decreased from 53 to 50. Cement leaks occurred in 20%. No significant difference was observed in functional improvements between groups. Radiographically kyphotic angle and anterior and middle vertebral body heights were significantly worse in the PVBW defect group (P < 0.05). BKP can alleviate pain and improve QoL and function in patients with cancer-related VCFs with PVBW defects with no appreciable increase in risk. J. Surg. Oncol. 2016;113:835-842. © 2016 Wiley Periodicals, Inc.

Long-term results still favor nonoperative treatment of stable thoracolumbar burst fractures: commentary on an article by Kirkham B. Wood, MD, et al.: "Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit. A prospective randomized study with follow-up at sixteen to twenty-two years".

Burst fractures of the thoracolumbar spine are common, but no consensus has been reached as to the best treatment. Although all burst fractures are characterized by the common finding of retropulsion of the posterior vertebral body wall into the spinal canal, burst fractures vary in severity with respect to amount of comminution, canal narrowing, associated neurologic deficit, and involvement of posterior structures. The latter structures are of primary importance in defining stability. To determine the best treatment, the authors conducted a randomized clinical trial from 1992 to 1998 in which they compared the outcomes of forty-seven patients who received either surgical or nonoperative treatment of a stable thoracolumbar burst fracture. This type of fracture has an intact posterior osteoligamentous complex. Nonoperative care consisted of bracing or casting. The surgical group was treated by anterior corpectomy and fusion with a plate or short-segment (two to four-level) posterior pedicle-screw instrumentation and arthrodesis. The …

Percutaneous Lumbar and Thoracic Pedicle Screws

Retrospective case study. Percutaneous pedicle screw (PPS) techniques do not allow direct visualization and may lead to erroneous screw placement. A technique utilizing only fluoroscopy is described. Verification of its accuracy and morphometric validation are presented. Minimally invasive spine surgical techniques, particularly PPS placement, have been growing in popularity. The purported benefits of minimally invasive spine surgical stated may be even more advantageous in the trauma setting. Jamshidi needles were docked in the typical starting position verified with posterior-anterior image. Jamshidi needle (20 mm) was advanced ensuring that the tip remained lateral to the medial pedicle wall. A Kirschner (K-wire) was placed through the needle. Once all the K-wires were placed, a lateral image was taken confirming the correct trajectory and that the wire passed the posterior vertebral body wall. Patients with PPS fixation were retrospectively studied with postoperative computed tomography to verify screw accuracy. Screw grade was assessed as grade I when completely within the pedicle, II <2 mm, III 2-4 mm, and IV >4 mm outside the pedicle. Morphometrically, 40 thoracic and lumbar computed tomography scans of patients (<40 y) without spine fractures were reviewed. The pedicle length was defined as the distance from the dorsal cortical margin to the posterior vertebral body in the pedicle's midaxis. A total of 172 screws were placed. Eighteen percent were found to have cortical breach, but only 2.9% were found to have >grade II breach. The morphometric study demonstrated the pedicle length to range from 14.4 to 22.1 mm. The shortest was in the upper thoracic and the longest at L1-L2. The morphometric study demonstrates if a K-wire is placed 20 mm into the bone and remains lateral to the medial pedicle wall and the tip just engages the vertebral body, the screw trajectory is safe particularly in the lower thoracic and upper lumbar spine. A smaller distance may be utilized in the upper thoracic. Breach rates are similar to other reports using other techniques; none were clinically significant. The advantage of this technique is the use of only PA fluoroscopy for placing all the wires percutaneously.

3:54 PM Abstract No. 55 - Irreversible electroporation (IRE) ablation of the lumbar vertebrae in a porcine model: a correlation of clinical, radiologic and pathologic findings

Purpose To evaluate the effects of IRE ablation of the lumbar vertebrae in pigs. Materials and Methods Sixteen CT-guided IRE ablations [transpedicular location, (n=8 vertebrae) and directly over the posterior cortex (n=8 vertebrae)] were performed in the lumbar vertebrae of 8 pigs. Magnetic resonance imaging (MRI) was obtained immediately prior to euthanasia at 2 or 7-days postablation. Clinical, imaging and histopathological data were analyzed. The maximum length and width of the ablation zone was measured on the T2 and T1 + contrast MRI sequences and compared with histopatholgic measurements. Miller’s low-bias back-transformation was used to construct 95% confidence intervals for the mean absolute percent difference using square root transformed data. Results IRE probe placement and ablation was successful in all cases. The mean distances from the IRE probe to the posterior wall of vertebral body or the exiting nerve root were 2.93 ± 0.77 mm and 7.87 ± 1.99 mm respectively. None of the animals had neurologic deficits or MRI findings of focal myelopathy or radiculopathy. Well delineated areas of necrosis of bone marrow and bone tissues, and acute degeneration and necrosis of skeletal muscle adjacent to the vertebral body were present. These lesions were associated with tissue repair changes in the 7-day postablation animals. Four of 8 ablations in the transpedicular group and 3 of 8 ablations in the posterior cortex group had minimal to moderate acute degenerative lesions of adjacent nerve roots that were not clinically significant. The absolute percent difference of ablation measurements between MRI sequences and histopathological lesions showed an average error range of 24.2-28.8% [95% CI: (12.2%, 47.3%)] on T2 and 26.1-33.3% [95% CI: (15.1%, 52.6%)] on T1+contrast sequences. Conclusion IRE ablation of the lumbar vertebrae in pigs is feasible, safe, and produces localized necrosis of the bone, bone marrow and muscle tissues. No neurological clinical symptoms were associated with this procedure. MRI signal changes are not accurate indicators of the ablation zone when compared with histopathologic findings.

Short-segment pedicle instrumentation with transpedicular bone grafting for nonunion of osteoporotic vertebral fractures involving the posterior edge

Most osteoporotic vertebral fractures (OVFs) can be treated successfully with conservative methods. In about 10% of patients, nonunion develops and warrants surgical management with minimally invasive procedures such as vertebroplasty and kyphoplasty. Nevertheless, for patients with nonunion fractures that involve the posterior vertebral body wall, vertebroplasty and kyphoplasty are relatively contraindicated due to the risk of extravertebral polymethylmethacrylate cement leakage through vertebral fracture cracks. To this end, we developed a method for pedicle screw fixation combined with transpedicular bone grafting for such a condition. Briefly, after posterior pedicle screw fixation and reduction in the affected vertebra, the demineralized bone matrix was inserted into the vertebral body via a 'bone grafting funnel' created through the pedicle of the affected vertebra. The current retrospective study analysed the safety and efficacy of this approach. A total of 12 patients who fulfilled the criteria were treated with this procedure. Visual analogue scale scores for back pain and anterior vertebral heights were recorded. At 3-month follow-up, pain was significantly relieved compared with presurgery and the anterior vertebral heights were successfully restored and maintained. In conclusion, short-segment pedicle instrumentation combined with transpedicular bone grafting is a useful alternative in the treatment of nonunion of OVFs with loss of posterior edge integrity.

Cement leakage as a possible complication of balloon kyphoplasty—is there a difference between osteoporotic compression fractures (AO type A1) and incomplete burst fractures (AO type A3.1)?

Besides the treatment of osteoporotic vertebral compression fractures of AO type A1, balloon kyphoplasty (BKP) is seen as a therapeutic option even in the treatment of incomplete osteoporotic burst fractures (AO type A3.1). However, due to involvement of the posterior vertebral body wall, the risk of cement leakages is considered to be higher. This study focuses on the frequency and pattern of cement leakages in AO type A3.1 fractures compared with osteoporotic compression fractures (AO type A1). Retrospective cohort analysis was done of all patients (n = 138) treated by BKP for osteoporotic vertebral fractures (n = 173) between January 2007 and December 2010 in our department. Cement extravasations into three pre-defined anatomical compartments were evaluated on postoperative CT scans of the augmented vertebral bodies, with even minor cement detections beyond the vertebral body's wall being strictly inidicated as leakages. The frequency of cement leakages in relation to the fracture type was statistically analyzed using Pearson's chi-square test. Clinical and radiological follow-up was done 6 weeks, 3 and 6 months postoperatively. The overall cement leakage rate of BKP in 173 treated osteoporotic vertebral fractures was 30.6%. Cement extravasations were detected in 20.3% of A1.1, 30.5% of A1.2, 37.8% of A1.3, and 39.0% of A3.1 fractures, respectively. There was no statistically significant difference in the leakage rate between A3.1 and all A1 fractures (28.0%; p > 0.05), but between A3.1 and A1.1 fractures (p < 0.05). Intraspinal cement extravasations, being the most dangerous, were seen in 25.5% of all leakages (n = 53), whereas in relation to the total number of treated fracture types, there were only 5.1% intraspinal leakages in A1.1, 5.6% in A1.2, 10.9% in A1.3, and 9.8% in A3.1 fractures. Two of 13 patients with intraspinal leakages and 1 patient with a paraaortal anterolateral cement extravasation needed surgical revisions. Two pulmonary PMMA cement embolisms were detected, but without any clinical consequences. None of the patients with cement leakages during BKP suffered from new neurological deficits. Cement leakages remain a problem in BKP. Although there was no significant difference between AO type A3.1 and all A1 fractures, subgroup analysis revealed a statistically significant higher risk of cement extrusions in A3.1 compared to A1.1 fractures. None of the affected patients showed new neurological deficits due to cement extravasations. Still, balloon kyphoplasty can be considered a safe procedure, even in the treatment of painful osteoporotic vertebral fractures of AO type A3.1.

Percutaneous Vertebroplasty for Pain Management in Spinal Metastasis with Epidural Involvement

Percutaneous vertebroplasty (PVP) has been widely used for the treatment of painful malignant lesions of the spine. Spinal metastasis with epidural involvement, with or without symptoms of neurologic compression, is regarded by some authors as a contraindication or relative contraindication to the procedure. To evaluate safety and effectiveness of PVP in pain management of spinal metastasis with epidural involvement, we retrospectively analyzed PVP in 32 patients with metastatic disease, who presented with at least one vertebral lesion with destruction of the posterior vertebral body wall or epidural extension of tumor. Among these patients, nine had signs of spinal cord or cauda equina compression. Procedural safety was evaluated by any post-procedure adverse events. The PVP analgesic efficacy was evaluated by follow-up neurological examination. Pain intensity was scored on a visual analog scale scored from 0 (no pain) to 10 (maximum pain intensity). The effective pain relief was defined as at least 50% improvement in pain score as compared with pre- procedure baseline. Follow-up assessments were performed at 1 day; 1 week; 1, 3, and 6 months after the procedure. Fifty-three vertebrae in 32 patients were treated in this group. Analgesic efficacy in survival patients was rated at 97% (31/32) at 1day and 1 week, 86.7% (26/30) at 1 month, 82.3% (24/29) at 3 months, and 76.9% (20/26) at 6 months after procedure. Leakage of PMMA was detected in 64% (33/53) treated vertebrae. No systemic complications were observed in all treated patients.

Which is the ideal point of time to perform intraoperative 3D imaging in dorsal stabilisation of thoracolumbar spine fractures? A matched pair analysis

Introduction After dorsal stabilisation of vertebral fractures by an internal fixateur the postoperative computed tomography is a standard procedure to control the positions of the pedicle screws, the success of the reposition, the clearance of the spinal canal and to plane an additive secondary ventral stabilisation. An intraoperative scan with a 3D image intensifier may clarify these questions directly after the implantation with the possibility of an immediate correction of the implants. The aim of this study was to find out the optimal point of time to perform an intraoperative 3D scan and if a postoperative computed tomography is dispensable. Patients and methods Intraoperative 3D scans were carried out on 33 patients with thoracolumbar spine fractures (T11-L5) after bi-segmental fixateur interne montage (Group 1). A matched pair group of 33 patients (Group 2) with a 3D scan after implantation of pedicle screws was built. A postoperative computed tomography of the instrumented spinal section was done in all patients. The following measurements were done in sagittal and axial reconstruction planes and were compared: classification of screw positions, maximal axial diameter of pedicles, cortical perforation of the screws. Additionally in Group 1 the distance between the upper and lower end plates of the injured section, the height of posterior vertebral body wall, the dislocation of the posterior wall and the minimal diameter of the spinal canal were measured. Results The intraoperative scoring of pedicle screws positions and the measurement of pedicle width showed in both groups a significant accordance with the computed tomography determinations. The measurements “posterior wall dislocation” and “diameter of spinal canal” were only possible in 24 3D scans and showed a significant difference compared with the CT data. The picture quality in Group 2 was scored significantly better than for Group 1 with the complete assembly of the fixateur. Conclusion The ideal point of time for an intraoperative 3D imaging with the present intensifier generation is directly after pedicle screw insertion. The reliable determination of the spinal canal diameter, of posterior wall fragments and of the exact fracture morphology is only possible by postoperative computed tomography.

The study of treatment of osteoporotic thoracolumbar multi-vertebral compressive fractures by kyphoplasty with one balloon

To evaluate the effect of kyphoplasty in treating osteoporotic thoracolumbar multi-vertebral compressive fractures with one balloon. thirteen cases (37 vertebral bodies) of osteoporotic thoracolumbar multi-vertebral compressive fractures were treated. The patients were women, range 65 to 79 years old, and all with well intact posterior wall of vertebral body. 37 thoracolumbar vertebral bodies were treated by Kyphoplasty with one balloon under "C" armed imaging guiding. All 13 patients tolerated well. The mean height of the anterior, media and posterior vertebral bodies was (1.9 +/- 0.5) cm, (1.5 +/- 0.5) cm, (2.6 +/- 0.5) cm preoperatively and (2.1 +/- 0.4) cm, (2.2 +/- 0.4) cm, (2.8 +/- 0.5) cm postoperatively (P < 0.001). The mean kyphosis was improved from (31.3 +/- 14.1) degrees to (24.8 +/- 11.3) degrees. There was not back pain and deformed correction was maintained well after 17.3 months' follow up, No complication occurred. The balloon was not damaged, because the pressure was lower than usual pressure, the cost of patients was saved. In this study, we fulfilled small amount of cement in vertebral body which reduced the leakage of cement. Fracture of close vertebral body was also reduced because of lower stiffness and modulus of elasticity of adjacent vertebral body.