Virtual preoperative measurement and surgical manipulation of sagittal spinal alignment using a novel research and educational software program.

Understanding regional as well as global spinal alignment is increasingly recognized as important for the spine surgeon. A novel software program for virtual preoperative measurement and surgical manipulation of sagittal spinal alignment was developed to provide a research and educational tool for spine surgeons. This first-generation software program provides tools to measure sagittal spinal alignment from the occiput to the pelvis, and to allow for virtual surgical manipulation of sagittal spinal alignment. The software was developed in conjunction with Clifton Labs, Inc. Photographs and radiographs were imported into the software program, and a 2D virtual spine was constructed from the images. The software then measured regional and global sagittal spinal alignment from the virtual spine construct, showing the user how to perform the measurements. After measuring alignment, the program allowed for virtual surgical manipulation, simulating surgical procedures such as interbody fusion, facet osteotomy, pedicle subtraction osteotomy, and reduction of spondylolisthesis, as well as allowing for rotation of the pelvis on the hip axis. Following virtual manipulation, the program remeasured regional and global sagittal spinal alignment. Computer software can be used to measure and manipulate sagittal spinal alignment virtually, providing a new research and educational tool. In the future, more comprehensive programs may allow for measurement and interaction in the coronal, axial, and sagittal planes.

Neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults: a review and resynthesis of the literature.

OBJECT: An increasing emphasis is being placed on the preservation or restoration of neutral upright sagittal spinal alignment in both deformity surgery and routine spinal operations. Sagittal spinal alignment is becoming recognized as an important predictor of a patient's outcome after spinal surgery. In this literature review, the authors analyze data obtained from previously published studies conducted to evaluate neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults. METHODS: A review of the English-language literature was conducted to identify studies conducted to evaluate neutral upright sagittal spinal (occiput-pelvis) alignment in asymptomatic adult volunteers with no spinal disease. The authors identified 12 articles that met the strict primary inclusion criteria of the current study. From these articles, 23 angles and displacements were selected to depict neutral upright sagittal occiput-pelvis alignment. Pooled estimates of the mean and variance were calculated for angles and displacements that met secondary inclusion criteria. The greatest variation in the regional spinal curves occurred in the cervical spine from C-2 to C-7, whereas the greatest focal angulation in the spine occurred from L-4 to S-1. Sagittal spinal balance was maintained in a narrow range for alignment of the spine over the pelvis and femoral heads. CONCLUSIONS: Neutral upright sagittal occiput-pelvis alignment in asymptomatic adults has been well studied regionally. Despite a wide variation in the undulating lordotic and kyphotic regional curves from the occiput to the pelvis, sagittal spinal balance is maintained in a narrower range for alignment of the spine over the pelvis and femoral heads.

Vertebral column subtraction osteotomy for recurrent tethered cord syndrome in adults: a cadaveric study.

OBJECT: The standard treatment for lumbosacral tethered cord syndrome (TCS) in adults is surgical detethering. In patients with recurrent TCS, additional detethering operations are associated with increased risk of complications and subsequent scar formation. The authors studied the effect of undertaking a vertebral column subtraction osteotomy (VCSO) at the thoracolumbar junction to shorten the vertebral column and reduce neural element tension. METHODS: A model of TCS, developed in fresh-frozen human cadavers, was evaluated in three experiments. In Experiment 1, VCSO of 20 to 25 mm was performed at the T11-12 level. The vertebral column was sequentially shortened and the reduction in tension was measured separately in the terminal filum and the L-1 to S-3 or S-4 nerve roots. In Experiments 2 and 3 the reduction in tension was measured in the spinal cord after a VCSO and after simulating a traditional detethering operation. Vertebral column shortening produced tension reduction in all experiments. Tension decreased to less than 0.6 g in the terminal filum, L1-S3/4 nerve roots, and spinal cord after closure of a 20- to 25-mm VCSO. The mean +/- standard deviation of the deltatension/deltadistance was -0.242 +/- 0.019 g/mm for the terminal filum, -0.246 +/- 0.019 g/mm for the lumbar nerve roots, and -0.216 +/- 0.040 g/mm for the sacral nerve roots. A simulated traditional detethering operation required significant neural element release (detethering) to achieve spinal cord tension reduction equivalent to VCSO. CONCLUSIONS: A VCSO significantly reduced neural tension at the thoracolumbar junction. This novel procedure may provide an alternative to traditional surgical detethering when scarring is excessive and the risk of complications and retethering are high.

Subependymal giant cell astrocytoma in a genetically negative tuberous sclerosis complex adult: Case report.

INTRODUCTION: The well-described entity of Subependymal Giant Cell Astrocytoma (SEGA) in the setting of Tuberous Sclerosis Complex (TSC) is profound in current literature. It has been described in children as well as adults with or without identifiable clinical presentations of tuberous sclerosis. To our knowledge there has not been any report of a negative genetic workup of Tuberous Sclerosis Complex in an adult patient presenting with an isolated SEGA. CASE REPORT: We present a case of a 25-year-old female with no medical history who presented to the emergency room for headaches. Further workup included gadolinium enhanced MRI of the brain which revealed a homogenously enhancing mass in the left lateral ventricle with eccentric calcification and resultant obstructive hydrocephalus. A left frontal craniotomy with an interhemispheric transcallosal approach was taken for complete removal of the mass. DISCUSSION: Final pathological diagnosis was SEGA with suggestive cell population, positive GFAP and positive synaptophysin. Genetic testing included TSC1 (MLPA, DNA Sequencing) and TSC2 (MLPA, DNA Sequencing), which were all negative. The panel did not identify mutations associated with Tuberous Sclerosis. CONCLUSION: Rare cases of isolated SEGA have been reported in patients who do not have typical features of tuberous sclerosis, and may represent minimal penetrance of the disease with an attenuated phenotype. Negative genetic testing, as demonstrated, can be seen in adults with isolated SEGA. With a negative genetic workup of TSC, regular follow up may still be necessary; however this may prove to be low yield for identifying any TSC features in the future.

Bilirubin production and oxidation in CSF of patients with cerebral vasospasm after subarachnoid hemorrhage.

Delayed cerebral vasospasm after subarachnoid hemorrhage (SAH) remains a significant cause of mortality and morbidity; however, the etiology is, as yet, unknown, despite intensive research efforts. Research in this laboratory indicates that bilirubin and oxidative stress may be responsible by leading to formation of bilirubin oxidation products (BOXes), so we investigated changes in bilirubin concentration and oxidative stress in vitro, and in cerebral spinal fluid (CSF) from SAH patients. Non-SAH CSF, a source of heme oxygenase I (HO-1), and blood were incubated, and in vitro bilirubin production measured. Cerebrospinal fluid from SAH patients was collected, categorized using stimulation of vascular smooth muscle metabolism in vitro, and information obtained regarding occurrence of vasospasm in the patients. Cerebral spinal fluid was analyzed for hemoglobin, total protein and bilirubin, BOXes, malonyldialdehyde and peroxidized lipids (indicators of an oxidizing environment), and HO-1 concentration. The formation of bilirubin in vitro requires that CSF is present, as well as whole, non-anti-coagulated blood. Bilirubin, BOXes, HO-1, and peroxidized lipid content were significantly higher in CSF from SAH patients with vasospasm, compared with nonvasospasm SAH CSF, and correlated with occurrence of vasospasm. We conclude that vasospasm may be more likely in patients with elevated BOXes. The conditions necessary for the formation of BOXes are indeed present in CSF from SAH patients with vasospasm, but not CSF from SAH patients without vasospasm.

Bilirubin as a cerebrospinal fluid marker of sentinel subarachnoid hemorrhage: a preliminary report in pigs.

OBJECT: A model of subarachnoid hemorrhage (SAH) in pigs was developed to investigate bilirubin concentration in cerebrospinal fluid (CSF) as a potential marker of sentinel SAH. METHODS: Seven male Yorkshire pigs received a 250-microl injection of either whole autologous arterial blood (four animals) or isotonic saline (three animals) into the cisternae magna in an effort to produce volumetrically a model of sentinel SAH and a control injection model, respectively. Cerebrospinal fluid volumes of 100 microl were then collected from both the lumbar cistern and cisternae magna at 1 to 2-hour intervals for a total of 24 hours postinjection. The CSF was then tested for bilirubin. Mean concentrations of bilirubin (+/- standard deviation [SD]) obtained from the lumbar cistern 24 hours following the injection of blood or saline were 4.38 +/- 1.04 microM in the SAH animals and 1.02 +/- 0.05 microM in the controls. At 24 hours postinjection, mean concentrations (+/- SD) of cisternae magna bilirubin were 7.29 +/- 1.33 microM and 1.33 +/- 0.14 microM in the SAH animals and controls, respectively. In the SAH group, both the lumbar cistern and cisternae magna bilirubin concentrations differed significantly from baseline values 12 hours following SAH. CONCLUSIONS: Elevated concentrations of CSF bilirubin can be detected following a low-volume SAH, and the production of bilirubin occurred over a predictable time course. Twelve hours after hemorrhage, an elevated CSF bilirubin concentration was an indicator of hemolysis occurring in the subarachnoid spaces. The presence of bilirubin in CSF is a potential marker for differentiating SAHs from traumatic lumbar punctures in humans.

Video-assisted thoracoscopic dissection of the brachial plexus: cadaveric study and illustrative case.

OBJECTIVE: Standard surgical approaches to the brachial plexus require an open operative technique with extensive soft tissue dissection. A transthoracic endoscopic approach using video-assisted thoracoscopic surgery (VATS) was studied as an alternative direct operative corridor to the proximal inferior brachial plexus. METHODS: VATS was used in cadaveric dissections to study the anatomic details of the brachial plexus at the thoracic apex. After placement of standard thoracoscopic ports, the thoracic apex was systematically dissected. The limitations of the VATS approach were defined before and after removal of the first rib. The technique was applied in a 22-year-old man with neurofibromatosis who presented with a large neurofibroma of the left T1 nerve root. RESULTS: The cadaveric study demonstrated that VATS allowed for a direct cephalad approach to the inferior brachial plexus. The C8 and T1 nerve roots as well as the lower trunk of the brachial plexus were safely identified and dissected. Removal of the first rib provided exposure of the entire lower trunk and proximal divisions. After the fundamental steps to the dissection were identified, the patient underwent a successful gross total resection of a left T1 neurofibroma with VATS. CONCLUSION: VATS provided an alternative surgical corridor to the proximal inferior brachial plexus and obviated the need for the extensive soft tissue dissection associated with the anterior supraclavicular and posterior subscapular approaches.