Management of complex pediatric and adolescent spinal deformity.

OBJECT: The authors sought to analyze prospectively the outcome of surgery for complex spinal deformity in the pediatric and young adult populations. METHODS: The authors evaluate all pediatric and adolescent patients undergoing operative correction of complex spinal deformity from December 1997 through July 1999. No patient was lost to follow-up review (average 21.1 months). There were 27 consecutive pediatric and adolescent patients (3-20 years of age) who underwent 32 operations. Diagnoses included scoliosis (18 idiopathic, five nonidiopathic) and four severe kyphoscoliosis. Operative correction and arthrodesis were achieved via 21 posterior approaches (Cotrel-Dubousset-Horizon), seven anterior approaches (Isola or Kaneda Scoliosis System), and two combined approaches. Operative time averaged 358 minutes (range 115-620 minutes). Blood loss averaged 807 ml (range 100-2,000 ml). Levels treated averaged 9.1 (range three-16 levels). There was a 54% average Cobb angle correction (range 6-82%). No case was complicated by the patient's neurological deterioration, loss of somatosensory evoked potential monitoring, cardiopulmonary disease, donor-site complication, or wound breakdown. There was one case of hook failure and one progression of deformity beyond the site of surgical instrumentation that required reoperation. There were 10 minor complications that did not significantly affect patient outcome. No patient received undirected banked blood products. There was a significant improvement in cosmesis, and no patient experienced continued pain postoperatively. All patients have been able to return to their preoperative activities. CONCLUSIONS: Compared with other major neurosurgical operations, segmental instrumentation for pediatric and adolescent spinal deformity is a safe procedure with minimal morbidity and there is a low risk of needing to use allogeneic blood products.

Spinal neurenteric cysts and their relation to more common aspects of occult spinal dysraphism.

OBJECT: Neurenteric cysts are infrequently reported congenital abnormalities believed to be derived from an abnormal connection between the primitive endoderm and ectoderm. The authors report a series of 13 patients treated over a 50-year period. METHODS: Of the 13 patients, seven were female and six were male. Their ages at presentation ranged widely from 5 weeks to 52 years of age. Children presented more commonly with cutaneous stigmata of occult spinal dysraphism (OSD) whereas adults presented primarily with pain. Neurological deficit as a presenting symptom was less common in our series, a finding that reflects the slow growth of these lesions. In all but one patient some form of vertebral anomaly was associated with the cystic lesions, including two patients with Klippel-Feil abnormalities. There was a high incidence of associated forms of OSD including split cord malformation, lipoma, dermal sinus tract, and tethered spinal cord. In previous reports the authors have suggested that neurenteric cysts are more common in the cervical region and in a position ventral to the cord. In the present series these cysts most commonly occurred as intradural, extramedullary masses in the thoracolumbar region, situated dorsal to the spinal cord. The median follow-up period was 7.5 years, and postoperative outcome reflected a patient's preoperative neurological status; in no patient was outcome worsened due to surgery. CONCLUSIONS: Complete excision of the neurenteric cyst remains the treatment of choice, as subtotal excision is associated with recurrence.

Multilevel thoracic pedicle aplasia causing congenital thoracic kyphosis: case report.

OBJECTIVE AND IMPORTANCE: Congenital thoracic kyphosis is a rare cause of treatable myelopathy. Multilevel thoracic pedicle aplasia as a cause of this deformity has not been previously reported in the literature. We report a case and describe the surgical management and outcome. CLINICAL PRESENTATION: A 14-year-old boy presented to us with a 4-month history of back pain and slowly progressive spastic paraparesis. Radiographic studies revealed thoracic kyphosis and bilateral aplasia of the pedicles of T4-T8. INTERVENTION: The patient underwent surgical treatment via a posterior approach for decompression of T4-T8, followed by arthrodesis from T2 to T12, using a hook claw construct with multiple points of fixation and autologous bone grafting. CONCLUSION: Congenital vertebral anomalies may be clinically occult, and delayed presentation may occur in adolescence or adulthood. Aplasia of multiple thoracic pedicles can produce kyphotic deformities with neurological compromise. A posterior approach with multiple points of segmental instrumentation can be effective in treating kyphotic deformities that are flexible and of moderate severity (<75 degrees).

The safety of OP-1 for lumbar fusion with decompression-- a canine study.

OBJECTIVE: Bone morphogenetic proteins can serve as adjuncts to autologous bone to achieve bony fusion, and recombinant BMPs such as osteogenic protein-1 (OP-1) have the potential to replace autologous bone altogether as fusion substrate. However, relatively little is known about the safety of OP-1 for spinal fusion procedures. This study examined the effects of OP-1 intentionally placed in the subarachnoid space following thecal sac decompression, and used as graft substrate in a canine dorsolateral lumbar spine fusion model. METHODS: Lumbar decompression with dorsolateral fusion was performed on 30 canines. The dura was opened to simulate an intraoperative rent and OP-1 was placed in the subarachnoid space and in the fusion bed. Animals were sacrificed after 16 weeks and the spines were examined manually, radiographically and pathologically. RESULTS: All animals treated with OP-1 developed new bone in the subarachnoid space. This bone compressed the spinal cord, but no clinical or pathological features of neurotoxicity were noted. Mild spinal stenosis was noted at the site of dural decompression in the OP-1 treated animals. Over 80% of animals treated with OP-1 developed fusion as assessed by palpation (52% by CT criteria), while only 25% of control animals fused. CONCLUSIONS: Recombinant human OP-1 is effective at promoting fusion in a canine dorsolateral lumbar spine fusion model. However, bone growth can occur over exposed, decompressed dura, and it can form in the subdural and subarachnoid spaces. The use of OP-1 as an adjunct to spinal fusion appears to have merit, but its use must be carefully controlled to avoid unwanted bone formation and subsequent neural compression.

Anterior lumbar fusion with titanium threaded and mesh interbody cages.

The authors report their experience with 42 patients in whom anterior lumbar fusion was performed using titanium cages as a versatile adjunct to treat a wide variety of spinal deformity and pathological conditions. These conditions included congenital, degenerative, iatrogenic, infectious, traumatic, and malignant disorders of the thoracolumbar spine. Fusion rates and complications are compared with data previously reported in the literature. Between July 1996 and July 1999 the senior authors (C.I.S., R.P.N., and M.J.R.) treated 42 patients by means of a transabdominal extraperitoneal (13 cases) or an anterolateral extraperitoneal approach (29 cases), 51 vertebral levels were fused using titanium cages packed with autologous bone. All vertebrectomies (27 cases) were reconstructed using a Miami Moss titanium mesh cage and Kaneda instrumentation. Interbody fusion (15 cases) was performed with either the BAK titanium threaded interbody cage (in 13 patients) or a Miami Moss titanium mesh cage (in two patients). The average follow-up period was 14.3 months. Seventeen patients had sustained a thoracolumbar burst fracture, 12 patients presented with degenerative spinal disorders, six with metastatic tumor, four with spinal deformity (one congenital and three iatrogenic), and three patients presented with spinal infections. In five patients anterior lumbar interbody fusion (ALIF) was supplemented with posterior segmental fixation at the time of the initial procedure. Of the 51 vertebral levels treated, solid arthrodesis was achieved in 49, a 96% fusion rate. One case of pseudarthrosis occurred in the group treated with BAK cages; the diagnosis was made based on the patient's continued mechanical back pain after undergoing L4-5 ALIF. The patient was treated with supplemental posterior fixation, and successful fusion occurred uneventfully with resolution of her back pain. In the group in which vertebrectomy was performed there was one case of fusion failure in a patient with metastatic breast cancer who had undergone an L-3 corpectomy with placement of a mesh cage. Although her back pain was immediately resolved, she died of systemic disease 3 months after surgery and before fusion could occur. Complications related to the anterior approach included two vascular injuries (two left common iliac vein lacerations); one injury to the sympathetic plexus; one case of superficial phlebitis; two cases of prolonged ileus (greater than 48 hours postoperatively); one anterior femoral cutaneous nerve palsy; and one superficial wound infection. No deaths were directly related to the surgical procedure. There were no cases of dural laceration and no nerve root injury. There were no cases of deep venous thrombosis, pulmonary embolus, retrograde ejaculation, abdominal hernia, bowel or ureteral injury, or deep wound infection. Fusion-related complications included an iliac crest hematoma and prolonged donor-site pain in one patient. There were no complications related to placement or migration of the cages, but there was one case of screw fracture of the Kaneda device that did not require revision. The authors conclude that anterior lumbar fusion performed using titanium interbody or mesh cages, packed with autologous bone, is an effective, safe method to achieve fusion in a wide variety of pathological conditions of the thoracolumbar spine. The fusion rate of 96% compares favorably with results reported in the literature. The complication rate mirrors the low morbidity rate associated with the anterior approach. A detailed study of clinical outcomes is in progress. Patient selection and strategies for avoiding complication are discussed.

A new technique for the surgical management of unstable thoracolumbar burst fractures: a modification of the anterior approach and an outcome comparison to traditional methods.

This study was conducted to determine the safety, efficacy, and complication rate associated with the anterior approach in the use of a new titanium mesh interbody fusion cage for the treatment of unstable thoracolumbar burst fractures. The experience with this technique is compared with the senior authors' (C.S., R.W., and M.S.) previously published results in the management of patients with unstable thoracolumbar burst fractures. Between 1996 and 1999, 21 patients with unstable thoracolumbar (T12-L3) burst fractures underwent an anterolateral decompressive procedure in which a titanium cage and Kaneda device were used. Eleven of the 21 patients had sustained a neurological deficit, and all patients improved at least one Frankel grade (average 1.2 grades). There was improvement in outcome in terms of blood loss, correction of kyphosis, and pain, as measured on the Denis Pain and Work Scale, in our current group of patients treated via an anterior approach when compared with the results in those who underwent a posterior approach. In our current study the anterior approach was demonstrated to be a safe and effective technique for the management of unstable thoracolumbar burst fractures. It offers superior results compared with the posterior approach. The addition of the new titanium mesh interbody cage to our previous anterior technique allows the patient's own bone to be harvested from the corpectomy site and used as a substrate for fusion, thereby obviating the need for iliac crest harvest. The use of the cage in association with the Kaneda device allows for improved correction of kyphosis and restoration of normal sagittal alignment in addition to improved functional outcomes.

Surgical approaches for the management of idiopathic thoracic scoliosis and the indications for combined anterior-posterior technique.

The indications for surgical intervention in patients with idiopathic scoliosis have been well defined. The goals of surgery are to achieve fusion and arrest progressive curvature while restoring normal coronal and sagittal balance. As first introduced by Harrington, posterior fusion, the gold standard of treatment, has a proven record of success. More recently, anterior techniques for performing fusion procedures via either a thoracotomy or a retroperitoneal approach have been popularized in attempts to achieve better correction of curvature, preserve motion segments, and avoid some of the complications of posterior fusion such as the development of the flat-back syndrome. Anterior instrumentation alone, although effective, can be kyphogenic and has been shown to be associated with complications such as pseudarthrosis and instrumentation failure. Performing a combined approach in patients with scoliosis and other deformities has become an increasingly popular procedure to achieve superior correction of deformity and to minimize later complications. Indications for a combined approach (usually consisting of anterior release, arthrodesis with or without use of instrumentation, and posterior segmental fusion) include: prevention of crankshaft phenomenon in juvenile or skeletally immature adolescents; correction of large curves (75 degrees ) or excessively rigid curves in skeletally mature or immature patients; correction of curves with large sagittal-plane deformities such as thoracic kyphosis (> 90 degrees ) or thoracic lordosis (> 20 degrees ); and correction of thoracolumbar curves that need to be fused to the sacrum. Surgery may be performed either in a staged proceedure or, more commonly, in a single sitting. The authors discuss techniques for combined surgery and complication avoidance.

Angiography after aneurysm surgery: indications for "selective" angiography.

BACKGROUND: The need for postoperative cerebral angiography to confirm clip placement is largely a matter of the individual surgeon's preference, but in an atmosphere of limited health care resources and rising costs this attitude may need to be changed. METHODS: A series of 312 intracerebral aneurysms harbored in 227 consecutive patients were clipped by a single surgeon (WF) and studied with postoperative selective angiography. Clues were sought to identify which (if any) aneurysms were prone to require postoperative recognition of incomplete or inaccurate clipping. We examined aneurysmal size, patient's sex, age, preoperative Hunt/Hess Grade, and Fisher CT grade, to determine their relationship to poor surgical clipping results (residual aneurysm or major vessel occlusion). RESULTS: There were 13 cases of residual aneurysm (4.2%) and one case of major vessel occlusion (0.3%). Deep midline aneurysms (posterior circulation, anterior communicating artery) and ophthalmic (paraophthalmic) artery regions formed a group of patients with an increased risk of imperfect clip placement (8.2%; 13/157) as compared to patients with aneurysms in other locations (0.6%; 1/155) (p < 0.05). In addition, incompletely obliterated aneurysms proved to have a high rehemorrhage rate in this series. CONCLUSIONS: A retrospective analysis revealed that deep midline aneurysms are more prone to inadequate clipping, and therefore, as a bare minimum represent aneurysms requiring confirmatory postoperative evaluation. This contemporary series can be used as a basis to compare the results from intraoperative angiography.

Stimulated leukocyte adhesion in coronary microcirculation is reduced by a calcium antagonist.

The first step in the acute myocardial inflammatory response is leukocyte sequestration in the coronary microcirculation. To determine the location(s) of stimulated leukocyte deposition in the coronary microcirculation and the effects of the calcium antagonist, nisoldipine, on leukocyte adhesion, leukocytes were stimulated with the chemotactic peptide, N-formylmethionyl-leucyl-phenylalanine (FMLP) and blood cell adherence was evaluated using two methods. In vitro leukostasis was evaluated by measuring the extraction of white cells in nylon fiber columns. We found that diluted whole blood (DWB) demonstrated 30% granulocyte adherence. The chemotactic peptide FMLP (1 microM) significantly increased adherence to 69%. Pretreatment of the blood with nisoldipine (1 microM) immediately before FMLP significantly reduced the FMLP-induced adhesion to 47%. In the coronary microcirculation, FMLP caused a marked increase in leukocyte sequestration, primarily in coronary capillaries. The FMLP effect was somewhat transient because the washout of trapped white cells was similar in the vehicle and FMLP groups. Nisoldipine significantly reduced the FMLP-induced leukostasis in coronary capillaries (P < 0.05). The magnitude of the attenuation of leukostasis with nisoldipine was remarkably similar in both models, suggesting a direct effect of this agent on the blood rather than on the blood vessels. These findings offer another possible mechanism by which dihydropyridine calcium antagonists may be cardioprotective under pathophysiological conditions.