Patient Perspectives Regarding Ethics of Spinal Column Stimulators in the Surgical Management of Persistent Postoperative Neuropathic Pain.

OBJECTIVE: The aim of this study is to better understand perspectives of patients with persistent postoperative neuropathic pain (PPNP) and assess perceptions of the ethical issues surrounding their structural spinal surgeon also performing spinal cord stimulation (SCS). METHODS: Semistructured face-to-face interviews with 20 neurosurgical spine patients were conducted. Patients were recruited from the neurosurgery clinics at Toronto Western Hospital and were seen in consultation for PPNP. Interviews were transcribed and subjected to thematic analysis using open and axial coding. RESULTS: The range of the duration of participants' preoperative symptoms varied from one month to more than 20 years, and was primarily back dominant (13/20). The median time since patients most recently underwent spinal surgery was three years. The majority of patients (15/20) do not view their current condition of PPNP as a failure of their initial spine surgeon. The most commonly reported reason for this is that patients trusted their physician and clear communication between the physician and the patient, prior to their surgery, ensured an understanding of the goals of the procedure. Nearly unanimously (19/20), patients did not perceive an ethical problem with a surgeon performing a structurally corrective spinal surgery and subsequently also implanting a SCS device if the same patient that develops medically refractory PPNP. CONCLUSIONS: This is the first clinical qualitative study of values and ethical perceptions of patients with medically refractory PPNP. Our findings provide a framework for understanding the values of patients with PPNP and demonstrate that a strong surgeon-patient relationship can ameliorate concerns surrounding PPNP and SCS implantation.

Incidence and Prognosis of Spinal Hemangioblastoma: A Surveillance Epidemiology and End Results Study.

OBJECTIVE: Intradural spinal hemangioblastoma are infrequent, vascular, pathologically benign tumors occurring either sporadically or in association with von Hippel-Lindau disease along the neural axis. Described in fewer than 1,000 cases, literature is variable with respect to epidemiological factors associated with spinal hemangioblastoma and their treatment. The objective of this study was to evaluate the epidemiology of intradural spinal hemangioblastoma with the Surveillance, Epidemiology and End Results (SEER) database while also presenting an illustrative case. METHODS: The SEER database was queried for cases of spinal hemangioblastoma between 2000 and 2010 with the use of SEER*Stat software. Incidence was evaluated as a function of age, sex and race. Survival was evaluated with the Cox proportionate hazards ratio using IBM SPSS software evaluating age, sex, location, treatment modality, pathology and number of primaries (p = 0.05). Descriptive statistics of the same factors were also calculated. The case of a 43-year-old patient with a surgical upper cervical intramedullary hemangioblastoma is also presented. RESULTS: In the data set between 2000 and 2010, there were 133 cases with an age-adjusted incidence of 0.014 (0.012-0.017) per 100,000 to the standard USA population. Hemangioblastoma was the tenth most common intradural spinal tumor type representing 2.1% (133 of 6,156) of all spinal tumors. There was no difference in incidence between men and women with an female:male rate ratio of 1.05 (0.73-1.50) with p = 0.86. The average age of patients was 48.0 (45.2-50.9) years, and a lower incidence was noted in patients <15 years compared to all other age groups (p < 0.05). There was no difference in incidence amongst the different races. Treatment included surgical resection in 106 (79.7%) cases, radiation with surgery in 7 (5.3%) cases, and radiation alone was used in only 1 (0.8%) case, and no treatment was performed in 17 (12.8%) cases. Mortality was noted in 12 (9%) cases, and median survival of 27.5 months (range 1-66 months) over the 10-year period. Mortality was attributable to the malignancy in 3 (2%) cases. There was no statistically significant different in Cox hazard ratios for mortality for sex, race, treatment modality, pathology or number of primaries. CONCLUSIONS: Spinal hemangioblastoma represent a small fraction of primary intradural spinal tumors, and this study did not identify any difference in incidence between genders. Surgical treatment alone was the most common treatment modality. Overall prognosis is good, with 9% observed mortality over the 10-year period, with 2% mortality attributable to the malignancy.

High Rates of Undiagnosed Psychological Distress Exist in a Referral Population for Spinal Cord Stimulation in the Management of Chronic Pain.

BACKGROUND: Neuropathic pain affects various dimensions of patient health including physical, psychological, and socioeconomic. The spectrum of psychological dysfunction that accompanies this pain phenotype is unknown, as well as differences based on the etiology of the pain among patients referred for spinal cord stimulation (SCS). METHODS: We prospectively assessed SCS referral patients with neuropathic pain for features of psychological distress, either mood or anxiety. Demographic data included age, gender, diagnosis, marital status, and educational level. Screening tools were applied for neuropathic pain (Douleur Neuropathic Quatre and Leeds Assessment of Neuropathic Symptoms and Signs) and psychological distress (Beck Depression Inventory [BDI] and Beck Anxiety Inventory [BAI]). Descriptive statistics defined disease prevalence, compared by gender and diagnosis. Logistic regression correlated pain intensity with severity of psychopathology. RESULTS: Among 150 patients with suitable neuropathic pain diagnoses and no treatable structural pathology, 57% were women, median age was 54 years, and 35% and 42% admitted to routine smoking and alcohol use, respectively. The most common diagnoses were complex regional pain syndrome (46%) and failed back surgery syndrome (38%). Depression symptoms were screened positive by BDI in 63% of patients, and anxiety symptoms were screened positive by BAI in 23% of patients. Pain intensity correlated with BDI scores (p < 0.02) but not BAI scores (p = 0.43). CONCLUSION: The high frequency of depressive and anxiety symptoms screened by the Beck scores in this cohort is an order of magnitude higher than seen in the general population. That many of these cases are undiagnosed should motivate clinicians from primary care providers, comprehensive pain specialists, and surgeons to screen SCS patients for such psychopathology. This represents an opportunity to enhance overall pain management as well as success with invasive neuromodulation strategies.

Complications related to the use of spinal cord stimulation for managing persistent postoperative neuropathic pain after lumbar spinal surgery.

OBJECT Structural spinal surgery yields improvement in pain and disability for selected patients with spinal stenosis, spondylolisthesis, or a herniated intervertebral disc. A significant fraction of patients exhibit persistent postoperative neuropathic pain (PPNP) despite technically appropriate intervention, and such patients can benefit from spinal cord stimulation (SCS) to alleviate suffering. The complication profile of this therapy has not been systematically assessed and, thus, was the goal of this review. METHODS A comprehensive literature search was performed to identify prospective cohorts of patients who had PPNP following structurally corrective lumbar spinal surgery and who underwent SCS device implantation. Data about study design, technique of SCS lead introduction, and complications encountered were collected and analyzed. Comparisons of complication incidence were performed between percutaneously and surgically implanted systems, with the level of significance set at 0.05. RESULTS Review of 11 studies involving 542 patients formed the basis of this work: 2 randomized controlled trials and 9 prospective cohorts. Percutaneous implants were used in 4 studies and surgical implants were used in 4 studies; in the remainder, the types were undefined. Lead migration occurred in 12% of cases, pain at the site of the implantable pulse generator occurred in 9% of cases, and wound-related complications occurred in 5% of cases; the latter 2 occurred more frequently among surgically implanted devices. CONCLUSIONS Spinal cord stimulation can provide for improved pain and suffering and for decreased narcotic medication use among patients with PPNP after lumbar spinal surgery. This study reviewed the prospective studies forming the evidence base for this therapy, to summarize the complications encountered and, thus, best inform patients and clinicians considering its use. There is a significant rate of minor complications, many of which require further surgical intervention to manage, including lead migration or implant infection, although such complications do not directly threaten patient life or function.

Iatrogenic spondylolisthesis following laminectomy for degenerative lumbar stenosis: systematic review and current concepts.

OBJECT Decompression without fusion for degenerative lumbar stenosis is an effective treatment for both the pain and disability of neurogenic claudication. Iatrogenic instability following decompression may require further intervention to stabilize the spine. The authors review the incidence of postsurgical instability following lumbar decompression, and assess the impact of surgical technique as well as study design on the incidence of instability. METHODS A comprehensive literature search was performed to identify surgical cohorts of patients with degenerative lumbar stenosis, with and without preexisting spondylolisthesis, who were treated with laminectomy or minimally invasive decompression without fusion. Data on patient characteristics, surgical indications and techniques, clinical and radiographic outcomes, and reoperation rates were collected and analyzed. RESULTS A systematic review of 24 studies involving 2496 patients was performed, assessing both open laminectomy and minimally invasive bilateral canal enlargement. Postoperative pain and functional outcomes were similar across the various studies, and postoperative radiographie instability was seen in 5.5% of patients. Instability was seen more frequently in patients with preexisting spondylolisthesis (12.6%) and in those treated with open laminectomy (12%). Reoperation for instability was required in 1.8% of all patients, and was higher for patients with preoperative spondylolisthesis (9.3%) and for those treated with open laminectomy (4.1%). CONCLUSIONS Instability following lumbar decompression is a common occurrence. This is particularly true if decompression alone is selected as a surgical approach in patients with established spondylolisthesis. This complication may occur less commonly with the use of minimally invasive techniques; however, larger prospective cohort studies are necessary to more thoroughly explore these findings.

A pilot evaluation of the role of bracing in stable thoracolumbar burst fractures without neurological deficit.

STUDY DESIGN: Prospective, 2-center, observer-blinded, randomized controlled trial. OBJECTIVE: Investigate clinical and radiologic outcomes of bracing versus no-bracing in the treatment of stable thoracolumbar burst fractures. SUMMARY OF BACKGROUND DATA: Management of thoracolumbar burst fractures depends upon clinical presentation of neurological deficit and radiographic features of fracture severity. Neurologically intact patients with mild deformity and biomechanical stability may be treated with conservative therapy. METHODS: Patients with stable (AO type A3), single level, thoracolumbar burst fractures between T12 and L2 with no neurological deficit were randomized to nonoperative treatment with a customized thoracolumbosacral orthosis (TLSO) or no-brace. Self-reported clinical outcomes of pain, disability, and health-related quality of life, and radiographic outcomes of kyphotic progression and loss of vertebral height, assessed by 2 independent reviewers blinded to treatment group, were measured at 6 months follow-up. RESULTS: Twenty-three consecutive eligible patients were included (TLSO: n=12; no-brace: n=11). There were no between-group differences regarding level of injury (P=0.75) and baseline spine geometry including fractional canal compromise (P=0.49), anterior loss of vertebral body height (P=0.28), and sagittal Cobb angle (P=0.13). In-hospital stay was significantly shorter in the no-brace group (mean: 2.8±3.0 d) compared with the TLSO group (mean: 6.3±2.1 d; P=0.004). At follow-up there were no differences in anterior loss of vertebral body height (TLSO: 12.5%±10.2% vs. no-brace: 11.9%±8.1%; P=0.88), kyphotic progression (TLSO: 5.3±4.4 degrees vs. no-brace 5.2±3.6 degrees; P=0.93), adverse events, or self-reported clinical outcomes. CONCLUSIONS: Neurologically intact patients with stable thoracolumbar burst fractures treated with or without bracing had similar radiographic and clinical outcomes at 6 months follow-up. The no-brace group had shorter in-hospital lengths of stay. Conservative therapy involving early mobilization without brace immobilization may be warranted. Further studies with a larger series of patients and longer follow-up are required for conclusive findings.

Cosmetic and cognitive outcomes of positional plagiocephaly treatment.

PURPOSE: Positional plagiocephaly is an acquired deformation of an intrinsically normal infant skull by sustained or excessive extrinsic forces. Non-surgical techniques include counter-positioning, supervised prone time and orthotic molding for more refractory cases. Long-term effects of positional plagiocephaly on development remain undefined, and this study evaluated cosmetic and cognitive outcomes of plagiocephaly management. METHOD: Surveys were administered to parents of patients treated for positional plagiocephaly through the Children's Hospital of Eastern Ontario. Categorical responses interrogated cosmetic outcome, school performance, language skills, cognitive development and societal function. Pearson coefficient analysis tested outcomes dependency on gender, age, and plagiocephaly side at the 0.05 level of significance. RESULTS: Eighty respondents (51 male, 29 female) were divided as 58 right- and 22 left-sided pathology. Positional therapy was uniformly applied, and a helmet orthosis was utilized in 36% of cases. Median follow-up age was nine years with normal head appearance in 75% of cases. Only 4% of parents and 9% of patients observed significant residual asymmetry. These results did not vary by gender, age or deformity side. Left-sided disease predicted poorer language development and academic performance. Expressive speech abnormality occurred in twice as many patients with left-sided disease (36% versus 16%, p=0.04) along with three-fold greater special education requirements (27% versus 10%, p=0.04). CONCLUSIONS: Non-surgical plagiocephaly management achieved good cosmetic outcome among patients in this study. Children with left-sided disease frequently encountered difficulties with cognitive and scholastic endeavors, although the roles of the underlying disease and the treatment measures in this delay cannot be differentiated.

Proinflammatory cytokine expression profile in degenerated and herniated human intervertebral disc tissues.

OBJECTIVE: Prior reports document macrophage and lymphocyte infiltration with proinflammatory cytokine expression in pathologic intervertebral disc (IVD) tissues. Nevertheless, the role of the Th17 lymphocyte lineage in mediating disc disease remains uninvestigated. We undertook this study to evaluate the immunophenotype of pathologic IVD specimens, including interleukin-17 (IL-17) expression, from surgically obtained IVD tissue and from nondegenerated autopsy control tissue. METHODS: Surgical IVD tissues were procured from patients with degenerative disc disease (n = 25) or herniated IVDs (n = 12); nondegenerated autopsy control tissue was also obtained (n = 8) from the anulus fibrosus and nucleus pulposus regions. Immunohistochemistry was performed for cell surface antigens (CD68 for macrophages, CD4 for lymphocytes) and various cytokines, with differences in cellularity and target immunoreactivity scores analyzed between surgical tissue groups and between autopsy control tissue regions. RESULTS: Immunoreactivity for IL-4, IL-6, IL-12, and interferon-gamma (IFNgamma) was modest in surgical IVD tissue, although expression was higher in herniated IVD samples and virtually nonexistent in control samples. The Th17 lymphocyte product IL-17 was present in >70% of surgical tissue fields, and among control samples was detected rarely in anulus fibrosus regions and modestly in nucleus pulposus regions. Macrophages were prevalent in surgical tissues, particularly herniated IVD samples, and lymphocytes were expectedly scarce. Control tissue revealed lesser infiltration by macrophages and a near absence of lymphocytes. CONCLUSION: Greater IFNgamma positivity, macrophage presence, and cellularity in herniated IVDs suggests a pattern of Th1 lymphocyte activation in this pathology. Remarkable pathologic IVD tissue expression of IL-17 is a novel finding that contrasts markedly with low levels of IL-17 in autopsy control tissue. These findings suggest involvement of Th17 lymphocytes in the pathomechanism of disc degeneration.

Classification of symptomatic Chiari I malformation to guide surgical strategy.

BACKGROUND: Treatment options for Chiari I malformations include posterior fossa decompression (PFD) with additional techniques including laminectomy, intradural exploration, and duraplasty. Neuroimaging findings of cisterna magna volume, syringomyelia, and intraoperative ultrasonography may tailor surgical intervention. METHODS: We developed an algorithm classifying symptomatic Chiari I patients into three groups to define minimum operation. Without syringomyelia, the presence of cisterna magna defined Group A and the absence defined Group B. Patients with syrinx formed Group C. Mild structural pathology (Group A) or adequate space following PFD (Group B, normal intraoperative ultrasound (IOUS)) should be treated by PFD alone. Conversely, presence of syringomyelia (Group C) or inadequate space following PFD (Group B, abnormal IOUS) should additionally have duraplasty. We applied this algorithm to patients treated at a single institution over 16 years. RESULTS: Twenty-four symptomatic Chiari I malformation patients were divided into three groups that did not differ by age, gender, or extent of tonsillar ectopia. All patients treated by this algorithm experienced clinical and radiographic improvement. This included eight Group B patients who underwent PFD only (n=6) or additional duraplasty (n=2) decided by IOUS. CONCLUSION: Treatment of symptomatic Chiari I malformation may have inadequate outcome with conservative strategy or complications with aggressive strategy. This algorithm utilizes preoperative neuroimaging and intraoperative ultrasound to tailor intervention, with excellent clinical outcome and radiographic syrinx resolution on application to 24 patients. Further validation requires prospective multicenter evaluation with larger patient population.

Effect of US State Certificate of Need regulation of operating rooms on surgical resident training.

PURPOSE: Government regulation of health care services helps prevent costs associated with expansion and duplication of services in the United States. Certificate of Need (CON) helps restrict construction of ambulatory surgery facilities and hence controls delivery of surgical intervention, but concern exists about whether this affects resident exposure to an appropriate caseload. This study investigated how CON laws impact on surgical caseload as an index of resident surgical training. METHODS: This retrospective study used State Inpatient Data compiled by the Health Care Utilization Project. Mean per capita rates of 26 diverse surgical procedures were evaluated in 21 states with CON laws and 5 states without between 2004 and 2006. The proportion of procedures performed in teaching facilities was also assessed. Student's t-tests were used to evaluate differences in these parameters between regulated and non-regulated states (a = 0.05). Multivariate analysis of variance permitted evaluation of the types of procedures that underwent shift in location performed. RESULTS: States with CON laws did not differ significantly in procedural rates for any of the investigated surgical procedures; however, such regulation was associated with different trends in teaching center caseload, depending on the type of procedure. Complex procedures, such as Whipple operations (p = 0.14) or resection of acoustic neuroma (p = 0.37), underwent no redistribution. Conversely, common procedures that might have previously been performed in private settings, such as total hip replacement (p = 0.003) or mastectomy (p = 0.01), did occur more commonly in teaching facilities under CON regulation. CON law did not result in relocation of surgical procedures away from teaching institutions. CONCLUSIONS: These results suggest that government regulations do not discriminate against teaching facilities. Surgical residents in states with such regulation gain similar or superior exposure to procedures as residents in states without such laws.

Pediatric traumatic dural arteriovenous fistula.

BACKGROUND: Dural arteriovenous fistulas are uncommon lesions in children, with traumatic lesions suspected to arise from incomplete arterial injury in proximity to a vein or draining sinus. Management of symptomatic acquired lesions requires evaluation of patient presentation, neurological status, and pathoanatomic configuration, with special consideration required for surgery secondary to failed endovascular technique. CASE REPORT: A 12-year-old male sustained a bicycle fall causing a right temporo-parietal skull fracture associated with non-surgical right epidural hematoma and left contre-coup parietal contusion. Six-weeks later, he complained of a right temporal bruit with subsequent cerebral angiography demonstrating a dural-based fistula between the right middle meningeal artery and a dural vein draining into the sigmoid sinus. INTERVENTION: Endovascular treatment of this lesion with glue embolization and coiling was unsuccessful, with angiographic illustration of previously unobserved collateral vessels and coils occupying the sigmoid sinus. A right temporo-parietal craniectomy was required to excise the dural-based fistula, followed by dural defect repair with bovine pericardium and subsequent cranioplasty. Six years later the patient remains neurologically intact with no headaches or bruit. CONCLUSIONS: Dural arteriovenous fistula can uncommonly occur following traumatic injury in children. Partial injury to the middle mengineal artery may have established arterial communication with the draining vein that became ectatic and tortuous under high pressure. Failure of primary endovascular treatment may complicate secondary surgical intervention.

Postoperative surveillance magnetic resonance imaging for cerebellar astrocytoma.

INTRODUCTION: Patients with low grade astrocytomas generally have good prognosis when total resection can be achieved, but surveillance neuroimaging is commonly performed to detect recurrence or progression. This study evaluated the utility and yield of such strategy for pilocytic and non-pilocytic cerebellar astrocytomas. METHODS: A 20-year retrospective review was performed of patients undergoing resection of cerebellar astrocytoma at a single institution. A negative MRI string (NMS) ratio was computed as the fraction of total follow-up period over which surveillance neuroimaging was negative for recurrence or progression. Chi-squared analysis differentiated NMS ratio by resection extent and lesion histopathology. RESULTS: Twenty-eight patients with pilocytic (n=15) and non-pilocytic (n=13) astrocytoma underwent 34 craniotomies, with total resection in 19 cases. Surveillance MRIs (n=167) among total resection patients were uniformly negative for recurrent disease at average seven years follow-up (NMS ratio = 1.0). The 43 surveillance MRIs among subtotal resection patients revealed disease progression in two patients within six months of operation (NMS ratio = 0.78, p<0.05). No differences in NMS ratio were observed between pilocytic and non-pilocytic astrocytoma subtypes. DISCUSSION: This study illustrates pediatric patients with low-grade cerebellar astrocytomas undergoing total resection may not benefit from routine surveillance neuroimaging, primarily because of low recurrence likelihood. Patients with subtotal resection may benefit from surveillance of residual disease, with further work aimed at exploring the schedule of such follow-up.

Evaluation of ThinkFirst for kids injury prevention curriculum for grades 7/8.

BACKGROUND: Head injury causes substantial morbidity and mortality in children. The ThinkFirst For Kids (TFFK) program improves knowledge of safe behaviours in kindergarten to Grade 6 students. METHODS: This study evaluated the TFFK curriculum for grade 7/8 students. Knowledge acquisition was assessed quantitatively by an injury prevention test at baseline, at curriculum completion, and six weeks later. Participant experiences and behaviours were explored qualitatively by interviews and focus groups. RESULTS: Students (n=204) and teachers (n=6) from four schools participated in this study. Test scores improved from baseline (26.48+/-0.17, n=204), to completion (27.75+/-0.16, n=176), to six weeks post-completion (28.65+/-0.13, n=111) (p<0.05). Most students reported their decision-making and participation in risky behaviors was altered by the curriculum. INTERPRETATION: The TFFK curriculum may promote education about head injury prevention among Grade 7/8 students, with a suggestion of long-term knowledge retention. The curriculum was well-received and may be suitable to reduce risky behavior and injuries in children.

Intracranial tumors in first year of life: the CHEO experience.

INTRODUCTION: One seventh of pediatric brain tumors are diagnosed in the first year of life. With more widespread and accessible neuroimaging, these lesions are being diagnosed earlier, but there remains scant literature about their natural history. METHODS: A retrospective review was performed of brain tumor patients presenting to the Children's Hospital of Eastern Ontario (CHEO) through the last 34 years. Patients presenting in the first year of life, including symptoms, management features, and functional outcome, were analyzed using ANOVA and chi (2) statistics. RESULTS: Eighteen cases of brain tumors in the first year of life were identified: 12 suptratentorial, eight with benign histology, and six infratentorial all with malignant histology. Median age of presentation differed by lesion location (p = 0.05) and glial tumors were most common. Raised intracranial pressure was more than twice as prevalent with posterior fossa lesions (p < 0.01) with equivalent likelihood of increasing head circumference (p = 0.74), whereas seizures were more frequent with supratentorial tumors (p = 0.04). Gross total resection was achieved in 47% of patients, cerebrospinal fluid diversion was more frequently necessary among infratentorial lesions (p = 0.02), and adjuvant therapy was more utilized for infratentorial lesions (p < 0.01). Among eight surviving infants, seven had supratentorial tumors, five survived to adulthood, and six are functionally independent. CONCLUSIONS: Brain tumors in the first year of life represent 4.8% of patients treated at CHEO. Mode of presentation, utilization of adjuvant therapy, and survival depend on tumor location and histology, with worse prognosis for infratentorial lesions. One third of patients had acceptable functional outcome requiring no special assistance.

Brain tumors and epilepsy: pathophysiology of peritumoral changes.

Epilepsy commonly develops among patients with brain tumors, frequently even as the presenting symptom, and such patients consequently experience substantial morbidity from both the seizures and the underlying disease. At clinical presentation, these seizures are most commonly focal with secondary generalization and conventional medical management is often met with less efficacy. The molecular pathophysiology of these seizures is being elucidated with findings that both the tumoral and peritumoral microenvironments may exhibit epileptogenic phenotypes owing to disordered neuronal connectivity and regulation, impaired glial cell function, and the presence of altered vascular supply and permeability. Neoplastic tissue can itself be the initiation site of seizure activity, particularly for tumors arising from neuronal cell lines, such as gangliogliomas or dysembryoblastic neuroepithelial tumors. Conversely, a growing intracranial lesion can both structurally and functionally alter the surrounding brain tissue with edema, vascular insufficiency, inflammation, and release of metabolically active molecules, hence also promoting seizure activity. The involved mechanisms are certain to be multifactorial and depend on specific tumor histology, integrity of the blood brain barrier, and characteristics of the peritumoral environment. Understanding these changes that underlie tumor-related epilepsy may have roles in both optimal medical management for the seizure symptom and optimal surgical objective and management of the underlying disease.

Minimally invasive interbody fusion for revision lumbar surgery: technical feasibility and safety.

STUDY DESIGN: Retrospective chart review of one surgeon's practice. OBJECTIVE: We evaluate the perioperative morbidity of 43 patients undergoing minimally invasive lumbar interbody fusion to differentiate risks between primary and revision surgery candidates. SUMMARY OF BACKGROUND DATA: Minimally invasive approaches to the lumbar spine have rapidly evolved and the technical feasibility and safety of minimally invasive interbody fusion is well established. Revision surgery is technically more challenging and may cause avoidance of such approaches because of altered anatomy and absent bony landmarks. Description of minimally invasive surgery approaches among revision patients and the feasibility of such techniques demands clarification. METHODS: Forty-three consecutive minimally invasive transforaminal lumbar interbody fusions (TLIFs) and posterior lumbar interbody fusions (PLIFs) were reviewed. Estimated blood loss, operative time, and complication rates were compared between primary and revision patients using Student t tests. RESULTS: Seventeen revision surgery cases (40%) were compared with 26 primary surgeries (60%) to elucidate differences in operative time, estimated blood loss, and complications. Demographic variables were similar in both groups. Estimated blood loss trended higher among the PLIF group and among revision cases, though no statistical significance was observed. A higher rate of complications, most notably incidental durotomy, was observed among revision cases in both PLIF and TLIF patients. One patient undergoing primary surgery had an intraoperative pedicle fracture, and 1 patient undergoing revision surgery had an asymptomatic screw malposition. No patients had a major complication, nerve injury, infection, or conversion to an open procedure. CONCLUSIONS: Minimally invasive lumbar interbody fusion by revision surgery is technically feasible and is not associated with more blood loss or neurologic morbidity. However, revision surgery has a higher minor perioperative complication rate, particularly of incidental durotomy. These outcomes demand significant experience before attempting minimally invasive revision surgery in the lumbar spine.

Congenital tumors of the central nervous system: the MCH experience.

INTRODUCTION: Congenital brain tumors in the younger pediatric population are rare lesions that are histologically distinct from those in the older pediatric population. Malignant histology is common, with persistently poor outcomes despite accessible neuroimaging and evolving adjuvant therapy. There remains scant literature about the natural history of these patients because of rarity and varied institutional experiences. METHODS: A retrospective review was performed of congenital brain tumor patients surgically treated at the Montreal Children's Hospital (MCH) over a 22-year period. Patients presenting in the first year of life were evaluated for demographic information, presenting symptoms, lesion location, and management. Analysis was by median rank test and chi(2) statistics. RESULTS: 13 cases of congenital brain tumors were identified: 5 supratentorial and 8 infratentorial. Median age (p = 0.93) and gender (p = 0.57) did not differ by location, and predominant histologies were choroid plexus papilloma and primitive neuroectodermal tumor. Seizure activity was exclusive to supratentorial lesions (40%, p = 0.03), with hypotonia observed only among infratentorial lesions (50%, p = 0.02). There was equal incidence of hydrocephalus (69%, p = 0.57) and increasing head circumference (38%, p = 0.27) by lesion location. Supratentorial lesions were treated by total resection (n = 3), subtotal resection (n = 1), and biopsy (n = 1). Infratentorial lesions were treated by total resection (n = 1), subtotal resection (n = 2), biopsy (n = 1), no operation (n = 2), and decompressive laminectomy for two spinal lesions. CONCLUSIONS: Congenital brain tumor patients represent fewer than 2% of patients treated at MCH. An evolving understanding of management objectives for these lesions requires understanding institutional experiences. Patients with supratentorial lesions frequently present with seizures, hydrocephalus, and macrocrania, and more frequently underwent total resection at surgery.