Posterior Trans-Dural Repair of Iatrogenic Spinal Cord Herniation after Resection of Ossification of Posterior Longitudinal Ligament

Iatrogenic spinal cord herniation is a rare complication following spinal surgery. We introduce a posterior trans-dural repair technique used in a case of thoracic spinal cord herniation through a ventral dural defect following resection of ossification of the posterior longitudinal ligament (OPLL) in the cervicothoracic spine. A 51-year-old female was suffering from paraplegia after laminectomy alone for cervicothoracic OPLL. Magnetic resonance imaging revealed a severely compressed spinal cord with pseudomeningocele identified postoperatively. Cerebrospinal fluid leak and iatrogenic spinal cord herniation persisted despite several operations with duroplasty and sealing agent. Finally, the problems were treated by repair of the ventral dural defect with posterior trans-dural duroplasty. Several months after surgery, the patient could walk independently. This surgical technique can be applied to treat ventral dural defect and spinal cord herniation

Early Outcome of Posterior Cervical Endoscopic Discectomy: An Alternative Treatment Choice for Physically/Socially Active Patients

Anterior cervical discectomy and fusion (ACDF) is currently the standard treatment for cervical disc disease. Some patients wish to be treated with a less invasive method, because of their social/physical situations. Here we present one method of treatments for socially/physically active patients. Three patients had triceps weakness and mild posterior neck pain. The offending lesions were at the C6-7 level. All were middle-aged soldiers with families. If conventional ACDF were performed, they would have to retire from the military according to the regulation. They had to be able to perform military drills after the treatment if they were going to be able to keep their jobs. Because of their social/physical situations, all wanted to choose method with that they could treat the disease and keep their jobs. For these reasons, the posterior cervical endoscopic discectomies were performed. Ruptured fragments were successfully removed in all. The arm pain improved by more than 90% in two patients by 7 days and in the other patient by 2 months, respectively (excellent outcome by Macnab's criteria). None of the operations caused instability. All of the patients are currently able to successfully perform their military drills without difficulty. The posterior cervical endoscopic discectomy may be a promising alternative for the physically/socially active patients

Accuracy of Free Hand Pedicle Screw Installation in the Thoracic and Lumbar Spine by a Young Surgeon: An Analysis of the First Consecutive 306 Screws Using Computed Tomography

Study DesignA retrospective cross-sectional study.PurposeThe purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon.Overview of LiteratureFew articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon.MethodsThe index surgeon has performed spinal surgery for 2 years by himself. He performed fluoroscopy-assisted pedicle screw installation for his first year. Since then, he has used the free-hand technique. We retrospectively reviewed the records of all consecutive patients undergoing pedicle screw installation using the free-hand technique without fluoroscopy in the thoracic or lumbar spine by the index surgeon. Incidence and extent of cortical breach by misplaced pedicle screw was determined by a review of postoperative computed tomography (CT) images.ResultsA total of 36 patients received 306 free-hand placed pedicle screws in the thoracic or lumbar spine. A total of 12 screws (3.9%) were identified as breaching the pedicle in 9 patients. Upper thoracic spine was the most frequent location of screw breach (10.8%). Lateral breach (2.3%) was more frequent than any other direction. Screw breach on the right side (9 patients) was more common than that on the left side (3 patients) (p<0.01).ConclusionsAn analysis by CT scan shows that young spine surgeons who have trained under the supervision of an experienced surgeon can safely place free-hand pedicle screws with an acceptable breach rate through repetitive confirmatory steps

Continuous Brain-derived Neurotrophic Factor (BDNF) Infusion After Methylprednisolone Treatment in Severe Spinal Cord Injury

Although methylprednisolone (MP) is the standard of care in acute spinal cord injury (SCI), its functional outcome varies in clinical situation. Recent report demonstrated that MP depresses the expression of growth-promoting neurotrophic factors after acute SCI. The present study was designed to investigate whether continuous infusion of brain-derived neurotrophic factor (BDNF) after MP treatment promotes functional recovery in severe SCI. Contusion injury was produced at the T10 vertebral level of the spinal cord in adult rats. The rats received MP intravenously immediately after the injury and BDNF was infused intrathecally using an osmotic mini-pump for six weeks. Immunohistochemical methods were used to detect ED-1, Growth associated protein-43 (GAP-43), neurofilament (NF), and choline acethyl transferase (ChAT) levels. BDNF did not alter the effect of MP on hematogenous inflammatory cellular infiltration. MP treatment with BDNF infusion resulted in greater axonal survival and regeneration compared to MP treatment alone, as indicated by increases in NF and GAP-43 gene expression. Adjunctive BDNF infusion resulted in better locomotor test scores using the Basso-Beattie-Bresnahan (BBB) test. This study demonstrated that continuous infusion of BDNF after initial MP treatment improved functional recovery after severe spinal cord injury without dampening the acute effect of MP

Efficiency of lead aprons in blocking radiation − how protective are they?

Background: Despite the firmly established occupational risk of exposure to X-rays, they are used extensively in spine surgeries. Shielding by lead aprons is the most common protective practice. We quantified the level of their radiation blocking ability in a real-life setting. Methods: Single-center, prospective, randomized study of adult patients with degenerative lumbar disorders, scheduled to undergo posterior lumbar interbody fusion. Instrumentation was performed in either a robot-assisted, minimally invasive approach (RO) or a conventional, fluoroscopically-assisted, open approach (FA). Outcome measures included the quantitative measurement of the surgeon’s actual exposure to radiation, as recorded by thermo-luminescent dosimeters (TLD) worn both above and under the 0.5 mm thyroid and trunk lead protectors. Findings: Sixty four patients were included in this study, 34 in the RO cohort and 30 in the FA cohort. The radiation blocked by the aprons, represented as the ratio of the under-apron to above-apron TLDs, averaged 37.1% (range 25.4–48.3%, 95% confidence interval between 30.6–43.6%). In the RO cohort, the average per-screw radiation dose and time were 51.9% and 73.7% lower, respectively, than the per screw exposure in the FA cohort. Interpretation: The 0.5 mm lead aprons blocked just over one third of the radiation scattered towards the surgeon. Use of robotic-guidance in a minimally invasive approach provided for a reduction of 62.5% of the overall radiation the surgeon was exposed to during open conventional approach. We conclude that reduced radiation use (e.g. by using robotic guidance) is a more effective strategy for minimizing exposure to radiation than reliance on protection by lead aprons, and recommend utilization of practices and technologies that reduce the surgical team’s routine exposure to X-rays

Thoracic and lumbar laminoplasty using a translaminar screw: morphometric study and technique Clinical article

Object. The aim of this study was to describe a novel technique for laminoplasty in which translaminar screws are used in the thoracic and lumbar spine. Methods. The authors first performed a morphometric study in 20 control individuals using 3D reconstructed CT scans and spine simulation software to measure the lengths and diameters of the spaces available for translaminar screw placement from the T-1 to S-1. Based on the results of the morphometric study, the authors then attempted translaminar screw fixation in 5 patients (April 2007-July 2007) after en bloc laminectomy in the thoracic and lumbar regions. All patients had intradural lesions: 3 schwannomas, I cavernoma, and I arachnoid cyst. Results. The morphometric study in control individuals revealed that the safe trajectories for simulated screws measured 25-30 mm in length and 8-11 mm in diameter in the thoracic region (T1-12) and 26-34 mm in length and 6-7 mm in diameter in the lumbosacral region (L1-S1). This morphometric and simulation study showed that translaminar screw placement would be possible in practice. Five patients underwent en bloc laminoplasty and translaminar screw fixation in which the screws measured 2.7 min in diameter and 24 or 26 mm in length. Sixteen attempts at translaminar fixation were made in 8 vertebrae. Fourteen translaminar screws were successfully placed at the thoracic and lumbar levels. Two microplates had to be used because the laminae were too thin and narrow after further laminectomy with undercutting. There were no complications associated with the translaminar screws. The mean follow-up period was 14.5 months. There was no screw breakage or displacement. Solid osseous fusion was documented in 2 patients who underwent CT scanning 15 months postoperatively. Conclusions. The authors found that the laminoplasty and translaminar screw technique is feasible in the thoracic and lumbar regions, but further studies are needed to analyze the biomechanical effects and long-term outcomes in a large number of patients. (DOI: 10.3171/009.2.SPINE08257)Kretzer RM, 2006, J NEUROSURG-SPINE, V5, P527Best NM, 2006, J SPINAL DISORD TECH, V19, P98Wiedemayer H, 2004, SPINE, V29, pE333YUCESOY K, 2002, SPINE, V27, pE316Hara M, 2001, NEUROSURGERY, V48, P235Kawahara N, 1999, SPINE, V24, P1363Wiedemayer H, 1998, NEUROSURG REV, V21, P93KIMURA I, 1995, J BONE JOINT SURG BR, V77B, P956MARKWALDER TM, 1989, ACTA NEUROCHIR, V99, P58KAWAI S, 1988, SPINE, V13, P1245HIRABAYASHI K, 1983, SPINE, V8, P693PARKINSON D, 1977, SURG NEUROL, V8, P277RAIMONDI AJ, 1976, J NEUROSURG, V45, P555LOVE JG, 1966, J NEUROSURG, V25, P116

Life-Threatening Late Hemorrhage due to Superior Thyroid Artery Dissection After Anterior Cervical Discectomy and Fusion

Study Design. Case report. Objective. The object of this report is to identify causes of late bleeding after anterior cervical discectomy and to suggest an optimal management plan. Summary of Background Data. The anterior discectomy and fusion is one of the most common spine procedures for cervical disc disease. Although this procedure has a low postoperative morbidity rate, rarely fatal vascular complications occur, the majority of which can be predicted intraoperatively. However, causes of unpredicted delayed bleeding are not fully understood. Methods. We reviewed the hospital charts and radiographs of a patient who underwent coil embolization for late bleeding after anterior cervical discectomy with fusion (ACDF). Results. A 33-year-old man underwent ACDF for cervical discs at C3-C4 and C4-C5. Intraoperatively, there was no major bleeding and the operation was completed after meticulous hemostasis. The patient was discharged 6 days after surgery without complications. However, at 16 days after surgery, the patient revisited the emergency room with sudden progressive neck swelling and accompanying respiratory difficulty. Because the neck swelling was rapidly progressing, the wound was opened in the intensive care unit under local anesthesia due to suspicion of hematoma. After evacuating the hematoma, we encountered active bleeding, which was controlled with gauze packing, but we were unable to identify the bleeding focus. After intubation, emergency right common carotid angiography was performed. Dissection of the right superior thyroid artery with active bleeding was identified, and this was promptly embolized with coils. After angiographic intervention, the remnant hematoma was removed in an operating room. The patient was discharged 5 days later without complication. Conclusion. This is the first report that shows late hemorrhage due to superior thyroid artery dissection after ACDF. This case cautions that intraoperative injury to an artery, unrecognized at operation, may cause late hemorrhage.Lied B, 2008, ACTA NEUROCHIR, V150, P111, DOI 10.1007/s00701-007-1472-yMenon RK, 2008, ANN NY ACAD SCI, V1142, P200, DOI 10.1196/annals.1444.015Fountas KN, 2007, SPINE, V32, P2310Wang MC, 2007, SPINE, V32, P342Choi JW, 2006, SPINE, V31, pE891Karim A, 2006, NEUROSURGERY, V59, P705, DOI 10.1227/01.NEU.0000229056.02698.6EWong TC, 2005, ORTHOPEDICS, V28, P793Alzamora MG, 2005, NEURORADIOLOGY, V47, P282, DOI 10.1007/s00234-005-1343-2WATTERS WC, 1994, SPINE, V19, P2343JENIS LG, 1994, SPINE, V19, P1291

Bicortical Screw Purchase at Upper Instrumented Vertebra (UIV) Can Cause UIV Fracture After Adult Spinal Deformity Surgery: A Finite Element Analysis Study

Objective To examine the biomechanical stress distribution at the upper instrumented vertebra (UIV) according to unicortical- and bicortical purchase model by finite element analysis (FEA). Methods A T8 to Sacrum with implant finite element model was developed and validated. The pedicle screws were unicortically or bicortically inserted from T10 to L5, and each model was compared and the von Mises (VM) yield stress of T10 was calculated. According to the motion (flexion, extension, lateral bending, and axial rotation) of spine, boundary condition values were set as 15°, 15°, 10°, 4°. Results Although the 2 stress values did not show a significant difference between the unicortical- and bicortical purchase models in the flexion and extension, bicortical purchase model showed a larger stress distribution. However, the asymmetric behavior was significantly greater in the case of lateral bending (0.802 MPa vs. 0.489 MPa) and the rotation (5.545 MPa vs. 4.905 MPa). The greater stress was observed on the spinal body surface abutting the implanted screw. Although the maximum stress was observed around the implanted screw in the bicortical purchase model under axial loading, the VM stress of both models was not significantly different. Conclusion Bicortical purchase model showed a larger stress distribution than the unicortical model, especially in the case of lateral bending and the rotation behavior. Our biomechanical simulation by FEA indicates that bicortical fixation at UIV can be a risk factor for early UIV compression fracture after adult spinal deformity surgery