In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.
Sagittal imbalance; Pedicle subtraction osteotomy; Clinical outcome; Proximal junctional kyphosis; Complication
We sought to determine the surgical treatment and functional outcome and identify the predictors of survival in a retrospective cohort of patients with spinal cord ependymoma using data collected from the Korea Spinal Oncology Research Group database.
The data regarding 88 patients who had been surgically treated for histologically confirmed spinal cord intramedullary and extramedullary ependymoma from January 1989 to December 2009 were retrospectively reviewed.
Histopathological examination revealed myxopapillary ependymoma in 24 patients, ependymoma in 61 patients, and anaplastic ependymoma in 3 patients. Gross total removal was achieved in 72 patients, subtotal removal in 15 patients, and partial removal in 1 patient. Twenty patients were treated with postoperative radiation. Fifty-two patients had stable or improved postoperative neurological function, while 36 experienced neurological deterioration. A permanent decrease in McCormick classification grade was seen in 17 patients. The progression-free survival rate was 87% for all patients at 5 years and 80% at 10 years. During follow-up, local recurrence/progression was seen in 13 patients. Diffuse meningeal spread developed in 2 anaplastic ependymoma patients. Postoperative radiotherapy after incomplete resection did not significantly correlate with longer times to recurrence. Multivariate analysis revealed histology and surgical extent of resection as independent predictors of longer progression-free survival.
Gross total removal alone is a good treatment strategy for spinal ependymomas. Early diagnosis and surgery, before severe paralysis, are important to obtain good functional outcomes. Subtotal resection with radiation therapy for intramedullary lesions appears to offer no advantages over gross total removal.
myxopapillary ependymoma; radiation; spinal ependymoma; survival
To evaluate whether intraoperative neurophysiologic monitoring (IONM) with combined muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials is useful for more aggressive and safe resection in intramedullary spinal cord tumour (IMSCT) surgery.
Materials and Methods
We reviewed data from consecutive patients who underwent surgery for IMSCT between 1998 and April 2012. The patients were divided into two groups based on whether or not IONM was applied. In the monitored group, the procedures were performed under IONM using 75% muscle amplitude decline weaning criteria. The control group was comprised of patients who underwent IMSCT surgery without IONM. The primary outcome was the rate of gross total excision of the tumour on magnetic resonance imaging at one week after surgery. The secondary outcome was the neurologic outcome based on the McCormick Grade scale.
The two groups had similar demographics. The total gross removal tended to increase when intraoperative neurophysiologic monitoring was used, but this tendency did not reach statistical significance (76% versus 58%; univariate analysis, p=0.049; multivariate regression model, p=0.119). The serial McCormick scale score was similar between the two groups (based on repeated measure ANOVA).
Our study evaluated combined IONM of trans-cranial electrical (Tce)-mMEPs and SEPs for IMSCT. During IMSCT surgery, combined Tce-mMEPs and SEPs using 75% muscle amplitude weaning criteria did not result in significant improvement in the rate of gross total excision of the tumour or neurologic outcome.
Intraoperative monitoring; spinal cord neoplasm; sensitivity and specificity
A retrospective cross-sectional study.
The purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon.
Overview of Literature
Few articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon.
The 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.
A 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).
An 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.
Pedicle screw; Thoracic; Lumbar: Free hand; Accuracy; Safety
The purpose of this study is to compare a neuroprotective effect of thoracic cord neuromodulation to that of sacral nerve neuromodulation in rat thoracic spinal cord injury (SCI) model.
Twenty female Sprague Dawley rats were randomly divided into 4 groups: the normal control group (n=5), SCI with sham stimulation group (SCI, n=5), SCI with electrical stimulation at thoracic spinal cord (SCI + TES, n=5), and SCI with electrical stimulation at sacral nerve (SCI + SES, n=5). Spinal cord was injured by an impactor which dropped from 25mm height. Electrical stimulation was performed by the following protocol: pulse duration, 0.1ms; frequency, 20 Hz; stimulation time, 30 minutes; and stimulation duration at thoracic epidural space and S2 or 3 neural foramina for 4 weeks. Locomotor function, urodynamic study, muscle weights, and fiber cross sectional area (CSA) were investigated.
All rats of the SCI + TES group expired within 3 days after the injury. The locomotor function of all survived rats improved over time but there was no significant difference between the SCI and the SCI + SES group. All rats experienced urinary retention after the injury and recovered self-voiding after 3-9 days. Voiding contraction interval was 25.5±7.5 minutes in the SCI group, 16.5±5.3 minutes in the SCI+SES group, and 12.5±4.2 minutes in the control group. The recovery of voiding contraction interval was significant in the SCI + SES group comparing to the SCI group (p<0.05). Muscle weight and CSA were slightly greater in the SCI + SES than in the SCI group, but the difference was not significant.
We failed to establish a rat spinal cord stimulation model. However, sacral neuromodulation have a therapeutic potential to improve neurogenic bladder and muscle atrophy.
Electrical stimulation; Spinal cord injury; Neuroprotection; Neuromodulation
Granular cell tumors (GrCTs) of the spinal cord are rare benign tumors with a high rate of local recurrence. Only 6 cases of spinal GrCTs have been reported. GrCT is difficult to distinguish from other benign tumors such as schwannoma using imaging. A radiological "speckled dots" sign may be a useful differentiating feature of GrCT based upon experience with two cases and a review of the literature.
Granular cell tumor; Intradural extramedullary tumor; Spinal cord; Magnetic resonance imaging; Schwannoma
The purpose of this study is to evaluate neuroprotective effect of sacral neuromodulation in rat spinal cord injury (SCI) model in the histological and functional aspects.
Twenty-one female Sprague Dawley rats were randomly divided into 3 groups : the normal control group (CTL, n=7), the SCI with sham stimulation group (SCI, n=7), and the SCI with electrical stimulation (SCI+ES, n=7). Spinal cord was injured by dropping an impactor from 25 mm height. Sacral nerve electrical stimulation was performed by the following protocol : pulse duration, 0.1 ms; frequency, 20 Hz; stimulation time, 30 minutes; and stimulation duration, 4 weeks. Both locomotor function and histological examination were evaluated as scheduled.
The number of anterior horn cell was 12.3±5.7 cells/high power field (HPF) in the CTL group, 7.8±4.9 cells/HPF in the SCI group, and 6.9±5.5 cells/HPF in the SCI+ES group, respectively. Both the SCI and the SCI+ES groups showed severe loss of anterior horn cells and myelin fibers compared with the CTL group. Cavitation and demyelinization of the nerve fibers has no significant difference between the SCI group and the SCI+ES group. Cavitation of dorsal column was more evident in only two rats of SCI group than the SCI+ES group. The locomotor function of all rats improved over time but there was no significant difference at any point in time between the SCI and the SCI+ES group.
In a rat thoracic spinal cord contusion model, we observed that sacral neuromodulation did not prevent SCI-induced myelin loss and apoptosis.
Electrical stimulation; Spinal cord injury; Neuroprotection; Sacral nerve; Neuromodulation
The incidence of spontaneous spinal epidural hematoma (SSEH) is rare. Patients with SSEH, however, present disabling neurologic deficits. Clinical outcomes are variable among patients. To evaluate the adequate treatment method according to initial patients' neurological status and clinical outcome with comparison of variables affecting the clinical outcome.
We included 15 patients suffered from SSEH. Patients were divided into two groups by treatment method. Initial neurological status and clinical outcomes were assessed by the American Spinal Injury Association (ASIA) impairment scale. Also sagittal hematoma location and length of involved segment was analyzed with magnetic resonance images. Other factors such as age, sex, premorbid medication and duration of hospital stay were reviewed with medical records. Nonparametric statistical analysis and subgroup analysis were performed to overcome small sample size.
Among fifteen patients, ten patients underwent decompressive surgery, and remaining five were treated with conservative therapy. Patients showed no different initial neurologic status between treatment groups. Initial neurologic status was strongly associated with neurological recovery (p=0.030). Factors that did not seem to affect clinical outcomes included : age, sex, length of the involved spinal segment, sagittal location of hematoma, premorbid medication of antiplatelets or anticoagulants, and treatment methods.
For the management of SSEH, early decompressive surgery is usually recommended. However, conservative management can also be feasible in selective patients who present neurologic status as ASIA scale E or in whom early recovery of function has initiated with ASIA scale C or D.
Spinal epidural hematoma; Surgery; Conservative management; Outcome
Spinal cord hemangioblastomas are rare tumors. Despite their benign, slow-growing nature, they can cause severe neurological consequences. The purpose of this study was to evaluate variable factors, including clinical features, tumor findings, the extent of resection, and its recurrence or progression, which determine postoperative functional outcomes.
This study included sixteen patients at our institute who underwent microsurgical resection for sporadic spinal intramedullary hemangioblastomas and spinal intramedullary hemangioblastomas associated with von Hippel-Lindau (VHL) disease, between June 2003 and March 2012.
A total of 30 operations were performed. Total resection (TR) of the tumor was achieved in 10 patients, and subtotal resection (STR) was achieved in 6. Postoperatively, the initial presenting symptoms were improved in 18.7% of the patients and were unchanged in 56.3%, but 25% were worse. Stable postoperative neurological functions were found in 83% of patients with preoperative McCormick grade I, and TR was achieved in 75% of these patients. In the STR group, poorer neurological status was observed in one patient, despite multiple operations. There were no poorer outcomes in the four cases of VHL disease. Various factors were analyzed, but only a correlation between the pre- and postoperative neurological status was verified in the TR-group patients.
Preoperative focal neurological impairment and meticulous microsurgical manipulation may be predictors of favorable outcomes for solitary hemangioblastomas. In addition, the preservation of function is more important than the extent of resection in VHL disease.
Hemangioblastoma; Spinal cord; Functional outcome; Von Hippel-Lindau disease
We report a rare case of a spinal intramedullary ependymal cyst in a 46-year-old female and review the 17 pathologically proven cases in the literature. The patient presented with a two-week history of gradually increasing tingling in her left posterior thigh and calf. A preoperative magnetic resonance image revealed a well-defined intramedullary cystic lesion on the ventral side of the spinal cord at the T11 to T12 levels. The lesion was hyper intense in T2-weighted images and hypointense in T1-weighted. The patient underwent a right-side hemilaminectomy at the T11 to T12 levels and fenestration of the cyst wall. After having the cyst wall partially removed and communication established between the cyst and the subarachnoid space, the patient improved neurologically. A histological study of the surgical specimens revealed that the cyst wall consisted of glial cells lined by a simple cuboidal to columnar epithelium. An immunohistochemical examination of the cells lining the cyst wall was positive for S-100 protein, glial fibrillary acidic protein, epithelial membrane antigen, and cytokeratin. We suggest that the optimal treatment of intramedullary ependymal cysts creates adequate communication between the cyst and the subarachnoid space.
Ependymal cyst; Intramedullary; Spinal cord; Immunochemistry
Giant spinal schwannoma of the cauda equine involving many nerve roots is rare, and ossification is usually not observed in the schwannoma. A 21-year-old man presented with a 12-month history of urinary dysfunction and numbness below the buttocks. Plain radiography showed scalloping of the posterior surface of the vertebral bodies from L4 to the sacrum, and magnetic resonance imaging and computed tomography revealed a giant cauda equina tumor with dystrophic calcification. The tumor was completely removed, with intraoperative neurophysiologic monitoring. Histopathologic examination showed that the tumor was a schwannoma. The patient's postoperative course was uneventful, with urinary function and numbness gradually improving. Although a giant schwannoma accompanied by dystrophic calcification is extremely rare, such a tumor can be removed safely and completely by meticulous dissection and careful neuromonitoring of the cauda equina spinal nerves involved in the tumor.
Giant schwannoma; Cauda equina; Complete excision; Calcification; Neuromonitoring
Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.
Pedicle screw placement; Thoracic spine; Surgical anatomy; Free hand technique; Surgical technique; Cadaveric study
Iliac screw fixation has been used to prevent premature loosening of sacral fixation and to provide more rigid fixation of the sacropelvic unit. We describe our technique for iliac screw placement and review our experience with this technique.
Thirteen consecutive patients who underwent spinopelvic fixation using iliac screws were enrolled. The indications for spinopelvic fixation included long segment fusions for spinal deformity and post-operative flat-back syndrome, symptomatic pseudoarthrosis of previous lumbosacral fusions, high-grade lumbosacral spondylolisthesis, lumbosacral tumors, and sacral fractures. Radiographic outcomes were assessed using plain radiographs, and computed tomographic scans. Clinical outcomes were assessed using the Oswestry Disability Index (ODI) and questionnaire about buttock pain.
The median follow-up period was 33 months (range, 13-54 months). Radiographic fusion across the lumbosacral junction was obtained in all 13 patients. The average pre- and post-operative ODI scores were 40.0 and 17.5, respectively. The questionnaire for buttock pain revealed the following: 9 patients (69%) perceived improvement; 3 patients (23%) reported no change; and 1 patient (7.6%) had aggravation of pain. Two patients complained of prominence of the iliac hardware. The complications included one violation of the greater sciatic notch and one deep wound infection.
Iliac screw fixation is a safe and valuable technique that provides added structural support to S1 screws in long-segment spinal fusions. Iliac screw fixation is an extensive surgical procedure with potential complications, but high success rates can be achieved when it is performed systematically and in appropriately selected patients.
Spinopelvic fixation; Iliac screws; Lumbosacral fusion; Outcome; Complication
Liposarcomas are malignant tumors of the soft tissue, with myxoid liposarcoma being the second most common subtype, tending to occur in the limbs, particularly in the thighs. Myxoid liposarcomas have an intermediate prognosis between well-differentiated and pleomorphic tumors. Spinal metastasis is usual but intradural involvement is extremely rare. We present an unusual case of a multicentric myxoid liposarcoma with intradural involvement. A 41-year-old woman complained of tingling sensation on her left arm. Radiological evaluation revealed multiple masses in her cervical spine, abdominal wall, liver, heart and right thigh, all of which were resected. She was histologically diagnosed with small round cell myxoid sarcoma and underwent adjuvant chemotherapy. However, magnetic resonance imaging analysis after 1 year revealed a large metastatic mass with bony invasion at the C6-T1 level. This mass consisted of extradural and intradural components causing severe compression of the spinal cord. She underwent resection via a posterior facetectomy of C6-7 and an anterior C7 corpectomy. However, the patient died of multiple metastases 18 months after the first diagnosis.
Cervical spine; lntradural; Multicentric; Myxoid liposarcoma; Metastasis
Hodgkin's disease presenting with spinal cord compression owing to extradural and bone involvement is extremely unusual. A 48-year-old man presented with progressive lower extremity weakness resulting from spinal cord compression attributable to an epidural mass in the thoracic vertebrae. The patient underwent decompressive surgery, and was then treated with chemotherapy for Langerhans cell histiocytosis. However, the disease progressed, and we performed second decompressive surgery with stabilization. Subsequent histopathological investigations revealed Hodgkin's lymphoma of the bone. Here, we describe an unusual case of spinal Hodgkin's lymphoma and Langerhans cell histiocytosis to draw attention to this combination as a possible diagnosis in patients with mixed inflammatory cell infiltrate lesions in the spine.
Hodgkin's disease; Lymphoma; Langerhans cell histiocytosis; Spinal cord compression
Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes.
We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation.
Following surgery, lumbar lordosis increased from -14.1° ± 20.5° to -46.3° ± 12.8° (p < 0.0001), and the C7 plumb line improved from 115 ± 43 mm to 32 ± 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 late-onset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results.
Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results.
Sagittal imbalance; Pedicle subtraction osteotomy; Clinical outcome; Proximal junctional kyphosis; Complication
Ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine is rare, even in the Far East. A 45-year-old female presented with a 4-month history of progressive motor weakness in the lower extremities, numbness below the midthoracic area, and spastic gait disturbance. Neuroradiological examinations revealed massive OPLLs at the T4-T6 levels with severe anterior compression of the spinal cord. Anterior decompressive corpectomies with bone grafts were performed from T4 to T6 using a trans-thoracic approach. After surgery, the patient made an uneventful recovery. However, eleven years after surgery, the patient developed recurrent lower extremity weakness and spastic gait disturbance. De novo OPLLs at the C6-T2 levels were responsible for the severe spinal cord compression on this occasion. After second surgery, paralysis in both legs was resolved. We present a rare case of late cervicothoracic OPLL in a patient surgically treated for thoracic OPLL.
Cervicothoracic spine; Thoracic spine; Orssification of the posterio longitudinal ligament; Late occurrence; Anterior decompression
Tubular retractor system as a minimally invasive surgery (MIS) technique has many advantages over other conventional MIS techniques. It offers direct visualization of the operative field, anatomical familiarity to spine surgeons, and minimizing tissue trauma. With technical advancement, many spinal pathologies are being treated using this system. Namely, herniated discs, lumbar and cervical stenosis, synovial cysts, lumbar instability, trauma, and even some intraspinal tumors have all been treated through tubular retractor system. Flexible arm and easy change of the tube direction are particularly useful in contralateral spinal decompression from an ipsilateral approach. Careful attention to surgical technique through narrow space will ensure that complications are minimized and will provide improved outcomes. However, understanding detailed anatomies and keeping precise surgical orientation are essential for this technique. Authors present the technical feasibility and initial results of use a tubular retractor system as a minimally invasive technique for variaties of spinal disorders with a review of literature.
Tubular retractor; Minimally invasive surgery; Spinal disorders; Microendoscopic discectomy
In this study, we compared the paramedian interfascial approach (PIA) and the traditional midline approach (MA) for lumbar fusion to determine which approach resulted in the least amount of postoperative back muscle atrophy. We performed unilateral transforaminal posterior lumbar interbody fusion via MA on the symptomatic side and pedicle screw fixation via PIA on the other side in the same patient. We evaluated the damage to the paraspinal muscle after MA and PIA by measuring the preoperative and postoperative paraspinal muscle volume in 26 patients. The preoperative and postoperative cross-sectional area, thickness, and width of the multifidus muscle were measured by computed tomography. The degree of postoperative paraspinal muscle atrophy was significantly greater on the MA side than on the contralateral PIA side (-20.7% and -4.8%, respectively, p<0.01). In conclusion, the PIA for lumbar fusion yielded successful outcomes for the preservation of paraspinal muscle in these 26 patients. We suggest that the success of PIA is due to less manipulation and retraction of the paraspinal muscle and further studies on this technique may help confirm whether less muscle injury has positive effects on the long-term clinical outcome.
Paraspinal Muscle; Paramedian Approach; Muscle Atrophy; Lumbar Spine