Related Articles

Sudden appearance of new upper extremity motor function while performing neurophysiologic intraoperative monitoring during tethered cord release: a case report.

J Pediatr Orthop. 2010 Sep;30(6):624-8

Authors: Barley JL, Mooney JF, Glazier SS, Johnson T, Kornegay AL, Turner RP, Edwards JC

: Tethered cord syndrome occurs when the distal spinal cord or filum adheres to adjacent structures resulting in progressive sensorimotor deficits in the lower extremities, fecal and/or urinary incontinence, and musculoskeletal deformities. Tethering of the distal cord may be idiopathic, may be associated with an intraspinal abnormality such as a lipoma, but most commonly the distal spinal cord remnant is adherent to the area of the original dysraphism repair in patients with myelodysplasia. Surgery to untether the cord is indicated in patients with worsening pain symptoms, progressive limb deformity or spasticity, or before any acute correction of an associated spinal deformity. Neurophysiologic intraoperative monitoring is used to minimize the risk of inadvertent nerve root or spinal cord injury during the untethering procedure and to assess any changes in cord function at the time of an associated spinal deformity correction. We present a patient with a lumbar level myelodysplasia, Chiari II malformation, severe scoliosis, and tethered cord that underwent concurrent scoliosis correction and tethered cord syndrome surgery, who demonstrated immediate intraoperative improvement in neurophysiologic responses in a previously flaccid upper extremity after untethering. These monitoring changes correlated with clinical improvements noted by physicians and family postoperatively. LEVEL OF EVIDENCE: Level IV.

PMID: 20733431 [PubMed - in process]

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Evaluation of GPR50, hMel-1B, and ROR-alpha Melatonin-related Receptors and the Etiology of Adolescent Idiopathic Scoliosis.

J Pediatr Orthop. 2010 Sep;30(6):539-43

Authors: Shyy W, Wang K, Gurnett CA, Dobbs MB, Miller NH, Wise C, Sheffield VC, Morcuende JA

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity in children. Studies have shown low melatonin levels resulting from pinealectomy in chickens and mice result in the development scoliosis, whereas supplementation with melatonin after the pinealectomy prevented it. The mere characterization of low melatonin levels is not sufficient to explain the development of idiopathic scoliosis in primates and humans, but we hypothesize that a mutation in melatonin-related receptors may be involved with the development of scoliosis. METHODS: The coding, splice-site, and promoter regions of 3 melatonin-related receptors (hMel-1B, RORalpha, and GPR50) were evaluated by DNA sequencing for variants associated with the phenotype of adolescent idiopathic scoliosis. An initial screening of 50 scoliosis patients with adolescent idiopathic scoliosis was compared with 50 controls by DNA sequencing of the 3 receptors. Additional cases and controls were evaluated when genetic variants were observed (for a total of 885 individuals). RESULTS: No significant differences were found in the hMel-1B and RORalpha receptors. We found 2 cSNPs in GPR50 (rs561077 and rs13440581) in the initial 50 patients. To evaluate the significance of these cSNPs, an additional 356 patients and 429 controls were analyzed. When the combined groups were analyzed, no significant associations were observed. CONCLUSIONS: Despite the observed relationship between melatonin and scoliosis, there is no significant association between mutations found in any known melatonin-related receptors with adolescent idiopathic scoliosis. The strong evidence of a melatonin-related cause for the development of idiopathic scoliosis still encourages research into undiscovered melatonin-related receptors, melatonin-related hormones, and the catalytic enzymes for the serotonin-melatonin pathway. CLINICAL RELEVANCE: This investigation is a genetic testing of the remaining currently known melatonin-related receptors that have not been analyzed earlier for association with AIS. Given the support in the literature of a relationship between melatonin and AIS, we have shown no mutations in any of the known melatonin-related receptor in patients with AIS.

PMID: 20733416 [PubMed - in process]

[Accuracy of pedicle screw insertion in the thoracolumbar spine using image-guided navigation.]

Neurocirugia (Astur). 2010 Aug;21(4):306-311

Authors: Fuster S, Vega A, Barrios G, Urdaneta I, Ojeda O, Macchia M, Combalia A, Berenguer J, Pujol T

INTRODUCTION. Computer image guidance is one of the most significant technologic advancements in the spine surgery, because preoperative or intraoperative images can be used for multiplanar, three-dimensional intraoperative navigation. MATERIAL AND METHODS. We performed a prospective clinical study to assess the accuracy of pedicle screw insertion using an optoelectronic navigation system (SurgiGATE Spine 2.1 Medivision). The study population included 29 patients with diverse disorders of the thoraco- lumbar spine (degenerative 54%, spondylolisthesis 21%, fractures 14%, scoliosis 7% and spondylodiscitis 4%). One patient was excluded from the study because problems with the specific instruments or the computer system. Pre and post-operative axial computed tomography images were obtained for each patient and analyzed by two independent radiologists to placement accuracy. The correct location was defined accord to Heary scale in 5 grades. RESULTS. 163 image-guided thoraco-lumbar pedicle screws were placed 29 in the thoracolumbar spine and 134 in the lumbosacral spine. We achieved a completely intraosseous placement (Grade I) in 99.4% of lumbosacral spine screws and 100% of thoracolumbar spine screws. Only one misplaced screw (Grade III) in the pedicle of L III in the concavity of a scoliosis was reported. No implant related complications were noted. CONCLUSIONS. The low rate of misplaced screws in this prospective study compares favorably with previously published results. Our initial results indicate that Image-guided spinal surgery is a safe technique which improves surgical performance during posterior transpedicle stabilization.

PMID: 20725699 [PubMed - as supplied by publisher]

Autologous growth factors versus autogenous graft for anterior cervical interbody fusion: an in vivo caprine model.

J Neurosurg Spine. 2010 Aug;13(2):216-23

Authors: Cunningham BW, Sefter JC, Hu N, McAfee PC

OBJECT: Using an in vivo caprine model, authors in this study compared the efficacy of autologous growth factors (AGFs) with autogenous graft for anterior cervical interbody arthrodesis. METHODS: Fourteen skeletally mature Nubian goats were used in this study and followed up for a period of 16 weeks postoperatively. Anterior cervical interbody arthrodesis was performed at the C3-4 and C5-6 vertebral levels. Four interbody treatment groups (7 animals in each group) were equally randomized among the 28 arthrodesis sites: Group 1, autograft alone; Group 2, autograft + cervical cage; Group 3, AGFs + cervical cage; and Group 4, autograft + anterior cervical plate. Groups 1 and 4 served as operative controls. Autologous growth factors were obtained preoperatively from venous blood and were ultra-concentrated. Following the 16-week survival period, interbody fusion success was evaluated based on radiographic, biomechanical, and histological analyses. RESULTS: All goats survived surgery without incidence of vascular or infectious complications. Radiographic analysis by 3 independent observers indicated fusion rates ranging from 9 (43%) of 21 in the autograft-alone and autograft + cage groups to 12 (57%) of 21 in the autograft + anterior plate group. The sample size was not large enough to detect any statistical significance in these observed differences. Biomechanical testing revealed statistical differences (p < 0.05) between all treatments and the nonoperative controls under axial rotation and flexion and extension loading. Although the AGF + cage and autograft-alone treatments appeared to be statistically different from the intact spine during lateral bending, larger variances and smaller relative differences precluded a determination of statistical significance. Histomorphometric analysis of bone formation within the predefined fusion zone indicated quantities of bone within the interbody cage ranging from 21.3 +/- 14.7% for the AGF + cage group to 34.5 +/- 9.9% for the autograft-alone group. CONCLUSIONS: The results indicated no differences in biomechanical findings among the treatment groups and comparable levels of trabecular bone formation within the fusion site between specimens treated with autogenous bone and those filled with the ultra-concentrated AGF extract. In addition, interbody cage treatments appeared to maintain disc space height better than autograft-alone treatments.

PMID: 20672957 [PubMed - indexed for MEDLINE]

Healos graft carrier with bone marrow aspirate instead of allograft as adjunct to local autograft for posterolateral fusion in degenerative lumbar scoliosis: a minimum 2-year follow-up study.

J Neurosurg Spine. 2010 Aug;13(2):211-5

Authors: Ploumis A, Albert TJ, Brown Z, Mehbod AA, Transfeldt EE

OBJECT: The objective of this study was to examine the efficacy and safety of Healos graft carrier with bone marrow aspirate and local autograft compared with the results of allograft in patients with lumbar degenerative scoliosis undergoing posterolateral fusion. METHODS: Twenty-eight patients with degenerative scoliosis underwent posterolateral instrumented fusion and decompression. Patients were grouped according to the graft used. Group A consisted of 12 cases in which the authors used a Healos graft carrier, bone marrow aspirate, and local autograft, and Group B consisted of 16 cases in which the authors used cancellous allograft and local autograft. Patients were followed for a minimum of 2 years postoperatively in terms of pain (visual analog scale), function (Oswestry Disability Index), curve magnitude (Cobb angle), and fusion status (plain and dynamic radiographs). The 2 groups did not differ statistically significantly (p > 0.05) in age, sex, smoking habits, magnitude of preoperative visual analog scale score, Oswestry Disability Index score, Cobb angle, or number of levels requiring decompression and fusion. RESULTS: The groups had similar (p > 0.05) results in terms of pain, function, curve progression, and fusion rates at the 2-year follow-up examination. Radiographic fusion was achieved in all but 2 cases, 1 in each group, in which the patients were asymptomatic. Patients in the allograft group (Group B) showed evidence of fusion earlier than in the Healos group (p < 0.05). No toxicity from Healos graft was recorded. CONCLUSIONS: The combination of Healos hydroxyapatite sponge and bone marrow aspirate plus local allograft had significantly slower fusion rates but equal clinical outcomes compared with cancellous allograft plus local autograft when used for posterolateral fusion in patients with degenerative lumbar scoliosis.

PMID: 20672956 [PubMed - indexed for MEDLINE]