Percutaneous vertebroplasty and balloon kyphoplasty in the treatment of osteoporotic vertebral fractures: a prospective randomized comparison.

PURPOSE: The purpose of this study is to compare the efficacy and safety of percutaneous vertebroplasty (PVP) and balloon kyphoplasty (BKP) in the treatment of osteoporotic vertebral compression fractures. MATERIALS AND METHODS: Patients with osteoporotic vertebral body fractures (T4-L5) were randomized and not blinded to kyphoplasty (n = 69) or vertebroplasty (n = 70). The postoperative pain score (VAS) at 12 months was the primary end point. The radiographic results were evaluated in relation to the resolution of the fracture and the possible onset of further osteoporotic fractures during follow-up. RESULTS: A total of one hundred and thirty-nine patients were eligible for randomization (n = 70 for PVP group and n = 69 for BKP), and twenty-six patients (twenty in the BKP group and six in the PVP group) were excluded. The mean average age of patients was 73 years, and 82% of the patients were females. VAS pain score was significantly reduced after surgery in both groups, and there were no significant differences between the two groups in postoperative VAS score. There was a significant reduction in kyphotic wedge angle and improvement of the sagittal index in both groups, but there was no significant difference between the two groups. There was a significant higher risk incidence of adjacent level fractures in the vertebroplasty group. CONCLUSIONS: In terms of clinical outcomes, there were no differences between the two groups. Both showed a significant clinical improvement, vertebral body height restoration and reduction in the kyphotic angle. There was a significant higher risk of adjacent level fractures in the vertebroplasty group.

Revision surgery of spinal dynamic implants: a literature review and algorithm proposal.

INTRODUCTION: Dynamic stabilization of the spine has been performed since the 1990s with the double purpose of restoring spinal segmental stability and allowing residual movement at the operated level. When we take into account the different motion-preserving devices and the spinal areas where they are applied, we can identify three categories of spinal implants: anterior cervical, anterior lumbar, and posterior lumbar. However, as in all prosthetic procedures performed in orthopedic surgery, the life span of a joint replacement device is a central topic of discussion, and this is true also for spinal dynamic devices, being revision surgery a complex procedure in specific cases. MATERIALS AND METHODS: We performed a literature review on the different dynamic spinal implants and the most common causes of failure, providing clinical cases as illustrative options for revision surgery. RESULTS: The review of the literature showed a 11.3% to 22.6% revision rate in posterior lumbar dynamic systems, with a peak of 40.6% in case of adjacent segment disease. In lumbar TDRs, infection and severe dislocations are the most frequent causes of anterior revisions, while posterior pedicle screw fixation could be a suitable option in minimal subsidence or TDR displacement. An algorithm for the planning of revision surgery is proposed. CONCLUSIONS: Surgical revision of spinal dynamic implants could be a demanding surgery especially in anterior approaches. Anterior cervical revision remains globally safe, but careful preoperative evaluation of vessels and ureter are suggested to avoid intraoperative complications in the lumbar spine. In posterior revision, a proper sagittal alignment of the spine should be restored. These slides can be retrieved under Electronic Supplementary Material.

A new "keyhole" approach for multilevel anterior lumbar interbody fusion: the perinavel approach-technical note and literature review.

PURPOSE: The purpose of this study is to evaluate the feasibility and the safety of a new skin incision for minimally invasive anterior lumbar interbody fusion (ALIF): the perinavel incision. METHODS: Demographic and clinical data from patients who underwent ALIF with the perinavel incision were collected. Indications to surgery, preoperative symptoms, radiological data, number of treated levels, intraoperative and early postoperative complications and wound-related problems were analysed. RESULT: Ninety-seven patients underwent ALIF with this new skin incision. One hundred fifty-seven levels were treated (mean 1.7 level per patient) being L4-L5 the most frequently treated. Intraoperative complications were represented only by the venous injury with a rate of 3.09% (3 cases). Postoperative complications were all linked to skin incision issues: a case of wound dehiscence and a case of superficial infection. No case of skin necrosis occurs at 3-month follow-up. CONCLUSIONS: In this paper, the perinavel skin incision was demonstrated to be as safe as traditional approaches for ALIF. Furthermore, with this incision it is possible to perform multilevel (L3-S1) ALIF, which means a good option in minimally invasive surgery as well as revision surgery. These slides can be retrieved under Electronic Supplementary Material.

Stability of housekeeping genes in human intervertebral disc, endplate and articular cartilage cells in multiple conditions for reliable transcriptional analysis.

Quantitative gene expression analysis is widely used to evaluate the expression of specific tissue markers. To obtain reliable data it is essential to select stable housekeeping genes whose expression is not influenced by the anatomical origin of cells or by the culture conditions. No studies have evaluated housekeeping gene stability in intervertebral disc (IVD) cells and only few studies using cartilaginous endplate (CEP) and articular cartilage (AC) cells are present in the literature. We analysed the stability of four candidate housekeeping genes (GAPDH, TBP, YWHAZ and RPL13A) in human cells isolated from nucleus pulposus (NP) and annulus fibrosus (AF), CEP and AC. Cell isolation, expansion, cryoconservation, and differentiation in 3D pellets were tested. GeNorm, NormFinder, BestKeeper tools and the comparative ΔCt method were used to evaluate housekeeping gene stability. In each cell population, TBP alone or combined with YWHAZ was identified as the best normaliser in both monolayer and 3D pellets. GAPDH was the best performer only for AC cells in monolayer. In most culture conditions considering groups of two or more cell types, TBP was the most stable and YWHAZ was the second choice. GAPDH was the best performer only in 3D pellets with factors for AC and AF combined with CEP cells. RPL13A was the most stable only for AF with CEP cells at isolation. Our findings will be useful to properly design the experimental set-up of studies involving IVD, CEP or AC cells in different culture conditions, in order to obtain accurate and high quality data from quantitative gene expression analysis.

Osteotomies in proximal junctional kyphosis in the cervicothoracic area.

INTRODUCTION: Proximal junctional kyphosis (PJK) of the cervicothoracic spine is a deformity that can affect patients who have undergone long thoracolumbar instrumented fusion. Preoperative hyperkyphosis of the thoracic spine and changes of more than 30° in lumbar lordosis are independent risk factors for the onset of PJK. METHODS: When PJK occurs in the cervicothoracic spine, extension of the fusion with eventual application of osteotomy techniques is frequently necessary to treat symptomatic patients or in case a neurological deficit occurs. Ponte osteotomy and pedicle subtraction osteotomy (PSO) are the two most used techniques to restore a good cervicothoracic alignment, although they are still demanding procedures even for expert surgeons. In junctional fractures, a vertebral column resection can be performed to support the anterior column. Ponte osteotomy ideally restores 10° at each treated level, while PSO allows a segmental correction up to 30°-35°. Adequate preoperative planning is fundamental for outlining the correct surgery and choosing the appropriate osteotomy. CONCLUSIONS: The aim of corrective surgery is to restore the cervicothoracic alignment, obtaining an adequate postoperative sagittal balance and decreasing the risk of further complications and new revision surgeries.

Variations of cervical lordosis and head alignment after pedicle subtraction osteotomy surgery for sagittal imbalance.

INTRODUCTION: The variations of the cervical lordosis after correction of sagittal imbalance have been poorly studied. The aim of our study is to verify whether the cervical lordosis changes after surgery for sagittal imbalance. MATERIALS AND METHODS: Thirty-nine patients were included in the study. Cervical, thoracic and lumbar spine, pelvic and lower-limb sagittal parameters were recorded. The cranial alignment was measured by the newly described Cranial Slope. RESULTS: The global cervical kyphosis (preop -43°, postop -31.5°) and the upper (preop -24.1°, postop -20.2°) and lower cervical kyphosis (preop -18.1°, postop -9.2°) were significantly reduced after surgical realignment of the trunk. A positive linear correlation was observed between the changes in T1 slope and the lower cervical lordosis, and between T1 slope and the global cervical alignment. CONCLUSIONS: The cervical lordosis is reduced by surgical correction of malalignment of the trunk, suggesting an adaptive role to maintain the head's neutral position.

Spinal osteotomies to treat post-traumatic thoracolumbar deformity.

Fractures of the thoracolumbar junction can lead to regional kyphosis, this being a significant cause of pain and disability for the patients. After a traumatic fracture of the thoracolumbar spine, early or late regional kyphosis can be observed. This post-traumatic deformity can, however, be corrected with appropriate surgical methods. Posterior tricolumnar osteotomies are some of the most powerful methods of correction and are particularly indicated when sagittal and coronal deformities have to be simultaneously corrected or when anterior surgery is not possible. Anterior corpectomy and lengthening with posterior instrumentation are, however, an alternative technique to restore the anterior column support and to correct the regional kyphotic deformity and an option for appropriate sagittal balance restoration and control of symptoms. Proper surgical technique, evaluation of the bone quality and identification of eventual extension of the deformity to the thoracic spine are key aspects in prevention of failures.

Standing lateral lumbar spine and pelvis (SLLP) radiograph: a screening, reduced radiation method, for sagittal imbalance.

INTRODUCTION: Sagittal imbalance is a predictor of failure after surgery for lumbar degenerative pathology. For this reason, specialists advocate correction of sagittal deformity and systematically perform preoperative standing whole spine films. Such diagnostic investigations expose patients to significant doses of radiation. The authors propose an easier radiographic investigation helpful as a screening test to identify patients likely to have sagittal imbalance. METHODS: Fifteen whole spine lateral films were evaluated, classifying subjects into three categories: balanced, compensating imbalanced or imbalanced. A second specialist evaluated the reduced SLLP versions of the film (from L1 to proximal femora), measuring spinopelvic parameters. RESULTS: In the SLLP film, the combination of two parameters (femoral inclination >10°, pelvic tilt >1/3 pelvic incidence +5°) identified 94 % of patients with altered sagittal balance. CONCLUSIONS: This study preliminarily suggests that the SLLP film can be a useful screening test for sagittal balance abnormalities.

Failures and revisions in surgery for sagittal imbalance: analysis of factors influencing failure.

INTRODUCTION: Sagittal imbalance is an important risk factor for spinal disability, pain and loss of health related quality of life. Its correction has a positive impact on these outcomes. Still, it is a very aggressive surgery, with a high revision rate. The aim of this study is to analyze the most important causes of failure of surgery for correction of sagittal imbalance. DESIGN AND METHODS: In this retrospective observational cohort study twelve patients who previously underwent surgery for sagittal imbalance correction were revised in the period 2009-10. We analyzed angular parameters of sagittal balance before and after primary surgery, type of instrumentation, modality of fusion, implant density, instrumented levels, modality of failure, time from first surgery and angular parameters after revision. RESULTS AND CONCLUSION: Causes of failure were insufficient correction, junctional kyphosis, screw loosening and pseudoarthrosis with rod breakage. In every case, patients presented a new onset or a worsening of sagittal imbalance and pain.

Preoperative calculation of the necessary correction in sagittal imbalance surgery: validation of three predictive methods.

INTRODUCTION: Surgery for correction of sagittal imbalance has frequent adverse events and complications. The most frequent cause of failure is inadequate correction of imbalance. The aim of this study is to verify the accuracy of three published methods (exact method by Ondra, FBI method by Le Huec and spinofemoral angle method by Lamartina) to preoperatively calculate the needed correction. DESIGN: This is a retrospective cohort study. METHODS: Fifteen patients treated for correction of sagittal imbalance, with preoperative and postoperative lateral standing whole spine radiographs, were identified. Preoperative calculation of the amount of needed correction has been done using these methods. In postoperative X-rays, the amount of correction obtained with and the degree of correction of sagittal imbalance have been measured. RESULTS AND DISCUSSION: The FBI and SFA methods obtain equivalent calculations of the amount of needed correction. The estimated correction angle with both methods is higher than that calculated with the exact trigonometric method. The difference between the latter and the former methods is equivalent to the observed excess of pelvic tilt.