The spine journal : official journal of the North American Spine Society
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The lateral transpsoas approach to interbody fusion is gaining popularity because of its minimally invasive nature and resultant indirect neurologic decompression. The acute biomechanical stability of the lateral approach to interbody fusion is dependent on the type of supplemental internal fixation used. The two-hole lateral plate (LP) has been approved for clinical use for added stabilization after cage instrumentation. However, little biomechanical data exist comparing LP fixation with bilateral pedicle screw and rod (PSR) fixation. ⋯ Based on these biomechanical findings, PSR fixation maximizes stability after lateral interbody cage placement. The nonradiographic technique served to quantify migration of implanted hardware and may be implemented as an effective laboratory tool for surgeons and engineers to better understand mechanical behavior of spinal implants.
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Although the influence of genetics on the process of disc degeneration is well recognized, in recently published studies, there is a wide variation in the race and selection criteria for such study populations. More importantly, the radiographic features of disc degeneration that are selected to represent the disc degeneration phenotype are variable in these studies. The study presented here evaluates the association between single nucleotide polymorphisms (SNPs) of candidate genes and three distinct radiographic features that can be defined as the degenerative disc disease (DDD) phenotype. ⋯ For the first time, genetic associations with DDD have been performed in an Indian population. Apart from identifying new associations, the highlight of the study was that in the same study population with DDD, SNP associations completely changed when different radiographic features were used to define the DDD phenotype. Our study results therefore indicate that standardization of the phenotypes chosen to study the genetics of disc degeneration is essential and should be strongly considered before planning genetic association studies.
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Acquired hyperpneumatization of the skull base and upper cervical vertebrae is extremely rare and is thought to occur in patients who habitually perform the Valsalva maneuver or engage in repetitive positive pressure activities such as scuba diving or free diving. Craniocervical hyperpneumatization has been reported to cause intracranial and extracranial pneumatoceles but is not generally considered as a cause of pneumorrhachis (air in the spinal canal). Pneumorrhachis is relatively rare, and usually occurs in a localized form, either in the cervical spine secondary to skull base fractures or in the thoracic spine secondary to pneumomediastinum or pneumothorax. Here, we report a case of extensive pneumorrhachis extending from the skull base to the thoracolumbar junction in association with marked axio-atlanto-occipital hyperpneumatization and pneumomediastinum. This unique constellation of findings likely resulted from complications of the Valsalva maneuver during strenuous exercise. ⋯ Craniocervical hyperpneumatization is a rare complication of the Valsalva maneuver. Most reported cases have involved only the skull base, or the skull base and C1, and many have been further complicated by microfractures leading to pneumocephalus or extracranial pneumatoceles. We present a unique case of extensive craniocervical hyperpneumatization that extended to the level of C2 and was complicated by microfractures causing severe pneumorrhachis. Concurrent pneumomediastinum in this case may have been an independent complication of the Valsalva maneuver, which could have contributed to pneumorrhachis. Alternatively, pneumomediastinum may have been caused by migration of gas through the neural foramen from the epidural space, driven by positive pressure generated by the one-way valve effect of the Eustachian tube during periods of exertion.
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The impact of patient factors and medical comorbidities on the risk of mortality and complications after spinal arthrodesis has not been well described. Prior works have been limited by small sample size, single center data, or the inability to be broadly generalized. ⋯ Several factors, including patients' age, BMI, ASA classification more than 2, pulmonary conditions, procedural times, and nutritional status likely influence the risk of postoperative morbidity to varying degrees. The risk factors identified here may be more generalizable to the American population as a whole because of the design and methodology of the NSQIP in comparison with previously published studies.
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Bone morphogenetic proteins (BMPs) induce osteogenesis, making them useful for decreasing time to union and increasing union rates. Although the advantages of BMP-2 as a substitute for iliac crest graft have been elucidated, less is known about the safety profile and adverse events linked to their use in spinal fusion. An accumulation of reactive edema in the epidural fat may lead to neural compression and significant morbidity after lumbar spinal fusion. Bone morphogenetic protein has never been implicated as a cause of spinal epidural lipedema. ⋯ We present a case of rapid accumulation of edematous adipose tissue causing cauda equina syndrome after a lumbar decompression and fusion surgery. The acute nature and extensive development of the lipedema presented in this case indicate an intense inflammatory reaction. We hypothesize that there may be a link between the use of BMP-2 and the accumulation of this edematous tissue. A thorough understanding of the mechanisms of BMP-2 and specific guidelines for their role in spinal surgery may improve functional outcomes and reduce the number of preventable complications. To the best of our knowledge and after a thorough literature search, this is the only reported case of epidural lipedema causing cauda equina syndrome.