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Competing Interests: The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. This study did not receive any funding or financial support. RG: consults for Balt Neurovascular, Cerenovus, Medtronic Neurovascular, Integra, Rapid Medical, and Stryker Neurovascular.

For nearly 90 years, notions of the brain have been inextricably associated with a homunculus that has become embedded within medical education as the precise representation of rolandic cortical function. We sought to define the history, evolution, accuracy, and impact of this pictorial means of showing cortical representation. We mathematically defined the evolutionary accuracy of appropriate homunculi using image analysis techniques for all points defined by Penfield, Boldrey, Rasmussen, Jasper, and Erickson, calculating perpendicular distances and defining areas and distributions of rolandic and sylvian regions labeled for sensory and motor activity with comparison with all homunculi. Prerolandic sensory representation composed 13%-47% of total sensory area (mean, 29%); postrolandic motor representation composed 15%-65% of total motor area (mean, 31%). Discrepancy between cortical perpendicular length attributed to a particular function on 1937 diagrams was greater than that attributed on the 1950 homunculus (motor: mean, 74%; range, 63%-96%; sensory: mean, 66%; range, 17%-92%) (P < 0.05). The homunculus, if truly drawn according to cortical mapping evidence, could never have been recognized as near humanoid, yet it has attained epic educational and practical longevity., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background and Objective: Both microvascular decompression (MVD) and Gamma Knife radiosurgery (GKRS) are time-tested treatment modalities for trigeminal neuralgia (TN). There is little evidence in the literature studying these modalities head to head in a cost-effectiveness comparison., Objective: To evaluate the cost-effectiveness of MVD compared with GKRS for treating patients with TN., Methods: We developed a Markov cost-effectiveness model for the U.S. health care system to account for all costs related to MVD and GKRS as treatment modalities for TN, from the health care system perspective, over a patient lifetime horizon. A base case was estimated using data from previous studies, from our own GKRS experience, and from a current data analysis of patients undergoing MVD. We derived model inputs, including health care costs, survival, and utility estimates, from the literature. We used age-specific, sex-specific, and race-specific mortality from national registries. Costs studied included those for MVD, for GKRS, for treating complications from either procedure, and for medications throughout patient lifetimes. We performed multiple 1-way, 2-way, and probabilistic sensitivity analyses to confirm the robustness of model assumptions and results. The incremental cost-effectiveness ratio (ICER), with a threshold of $50,000 per quality-adjusted life-year (QALY) gained, defined cost-effectiveness., Results: The base case had an ICER of $12,154 per QALY for MVD compared with GKRS. Probabilistic sensitivity (Monte Carlo) analysis showed that MVD was cost-effective in 70% of model iterations. GKRS was favored when the willingness to pay threshold was <$12,000 per QALY gained., Conclusions: In patients medically eligible for either procedure, we found MVD to be the most cost-effective modality to treat TN, primarily because of its reported greater durability. MVD remained the most cost-effective strategy across a broad range of model input values in sensitivity analyses., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Patients undergoing posterior spinal fusion surgery can lose a substantial amount of blood. This can prolong operative time and require transfusion of allogeneic blood components, which increases the risk of infection and can be the harbinger of serious complications. Does a saline-irrigated bipolar radiofrequency hemostatic sealer (RFHS) help reduce transfusion requirements?, Methods: In an observational cohort study, we compared transfusion requirements in 30 patients undergoing surgery for adult spinal deformity using the RFHS with that of a historical control group of 30 patients in which traditional hemostasis was obtained with bipolar electrocautery and matched them for blood loss-related variables. Total expense to the hospital for the RFHS, laboratory expenses, and blood transfusions was used for cost calculations. The incremental cost-effectiveness ratio was calculated using the number of blood transfusions avoided as the effectiveness payoff., Results: Using a multivariable linear regression model, we found that only estimated blood loss (EBL) was an independent significant predictor of transfusion requirement in both groups. We evaluated the variables of age, EBL, time duration of surgery, preoperative hemoglobin, hemoglobin nadir during surgery, body mass index, length of stay, and number of levels operated on. Mean EBL was greater in the control group (2201 vs. 1416 mL, P = 0.0099). The number of transfusions also was greater in the control group (14.5 vs. 6.5, P = 0.0008). In the cost-effectiveness analysis, we found that the RFHS cost $108 more (compared with not using the RFHS) to avoid 1 unit of blood transfusion., Conclusions: The cost-effectiveness analysis revealed that if we are willing to pay $108 to avoid 1 unit of blood transfusion, the use of the RFHS is a reasonable choice to use in open surgery for adult spinal deformity., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVE The price of coils used for intracranial aneurysm embolization has continued to rise despite an increase in competition in the marketplace. Coils on the US market range in list price from $500 to $3000. The purpose of this study was to investigate potential cost savings with the use of a price capitation model. METHODS The authors built a clinical decision analytical tree and compared their institution's current expenditure on endovascular coils to the costs if a capped-price model were implemented. They retrospectively reviewed coil and cost data for 148 patients who underwent coil embolization from January 2015 through September 2016. Data on the length and number of coils used in all patients were collected and analyzed. The probabilities of a treated aneurysm being ≤/> 10 mm in maximum dimension, the total number of coils used for a case being ≤/> 5, and the total length of coils used for a case being ≤/> 50 cm were calculated, as was the mean cost of the currently used coils for all possible combinations of events with these probabilities. Using the same probabilities, the authors calculated the expected value of the capped-price strategy in comparison with the current one. They also conducted multiple 1-way sensitivity analyses by applying plausible ranges to the probabilities and cost variables. The robustness of the results was confirmed by applying individual distributions to all studied variables and conducting probabilistic sensitivity analysis. RESULTS Ninety-five (64%) of 148 patients presented with a rupture, and 53 (36%) were treated on an elective basis. The mean aneurysm size was 6.7 mm. A total of 1061 coils were used from a total of 4 different providers. Companies A (72%) and B (16%) accounted for the major share of coil consumption. The mean number of coils per case was 7.3. The mean cost per case (for all coils) was $10,434. The median total length of coils used, for all coils, was 42 cm. The calculated probability of treating an aneurysm less than 10 mm in maximum dimension was 0.83, for using 5 coils or fewer per case it was 0.42, and for coil length of 50 cm or less it was 0.89. The expected cost per case with the capped policy was calculated to be $4000, a cost savings of $6564 in comparison with using the price of Company A. Multiple 1-way sensitivity analyses revealed that the capped policy was cost saving if its cost was less than $10,500. In probabilistic sensitivity analyses, the lowest cost difference between current and capped policies was $2750. CONCLUSIONS In comparison with the cost of coils from the authors' current provider, their decision model and probabilistic sensitivity analysis predicted a minimum $407,000 to a maximum $1,799,976 cost savings in 148 cases by adapting the capped-price policy for coils.

OBJECTIVE Lateral lumbar interbody fusion (LLIF) is a less invasive surgical option commonly used for a variety of spinal conditions, including in high-risk patient populations. LLIF is often performed as a stand-alone procedure, and may be complicated by graft subsidence, the clinical ramifications of which remain unclear. The aim of this study was to characterize further the sequelae of graft subsidence following stand-alone LLIF. METHODS A retrospective review of prospectively collected data was conducted on consecutive patients who underwent stand-alone LLIF between July 2008 and June 2015; 297 patients (623 levels) met inclusion criteria. Imaging studies were examined to grade graft subsidence according to Marchi criteria, and compared between those who required revision surgery and those who did not. Additional variables recorded included levels fused, DEXA (dual-energy x-ray absorptiometry) T-score, body mass index, and routine demographic information. The data were analyzed using the Student t-test, chi-square analysis, and logistic regression analysis to identify potential confounding factors. RESULTS Of 297 patients, 34 (11.4%) had radiographic evidence of subsidence and 18 (6.1%) required revision surgery. The median subsidence grade for patients requiring revision surgery was 2.5, compared with 1 for those who did not. Chi-square analysis revealed a significantly higher incidence of revision surgery in patients with high-grade subsidence compared with those with low-grade subsidence. Seven of 18 patients (38.9%) requiring revision surgery suffered a vertebral body fracture. High-grade subsidence was a significant predictor of the need for revision surgery (p < 0.05; OR 12, 95% CI 1.29-13.6), whereas age, body mass index, T-score, and number of levels fused were not. This relationship remained significant despite adjustment for the other variables (OR 14.4; 95% CI 1.30-15.9). CONCLUSIONS In this series, more than half of the patients who developed graft subsidence following stand-alone LLIF required revision surgery. When evaluating patients for LLIF, supplemental instrumentation should be considered during the index surgery in patients with a significant risk of graft subsidence.

A fetal MRI study obtained at 21 weeks' gestation revealed a suboccipital meningocele without hydrocephalus. One day after term birth, MRI demonstrated an acquired cerebellar encephalocele, and MRI obtained 5 months later showed progressive enlargement of the encephalocele, still without obvious hydrocephalus. The patient underwent an operation in which an external ventricular drain was placed, the grossly normal cerebellum was reduced into the posterior fossa without resection, and the dural defect was closed. The drain was weaned out over 5 days, and no ventriculoperitoneal shunt was placed. Postoperative MR images revealed normal cerebellum and no hydrocephalus. The patient is developmentally normal. Meningocele and encephalocele are embryologically distinct. An acquired encephalocele could develop from hydrocephalus (which was not present in this case), or secondary to the lower resistance to expansion into the dural defect of the meningocele relative to the resistance to expansion of the fetal skull. The cerebellar tissue was normal in this case, and was thus preserved. The developmental prognosis is excellent. To the authors' knowledge, this is the first reported case of this occurrence. It is important to differentiate between congenital and acquired encephalocele etiologies, because resection of the cerebellar tissue in an acquired encephalocele (as is routinely done in cases of congenital encephalocele) would be expected to result in neurological deficits.

Objective: To perform a cost-minimization study comparing the supraorbital and endoscopic endonasal (EEA) approach with or without craniotomy for the resection of olfactory groove meningiomas (OGMs)., Methods: We built a decision tree using probabilities of gross total resection (GTR) and cerebrospinal fluid (CSF) leak rates with the supraorbital approach versus EEA with and without additional craniotomy. The cost (not charge or reimbursement) at each "stem" of this decision tree for both surgical options was obtained from our hospital's finance department. After a base case calculation, we applied plausible ranges to all parameters and carried out multiple 1-way sensitivity analyses. Probabilistic sensitivity analyses confirmed our results., Results: The probabilities of GTR (0.8) and CSF leak (0.2) for the supraorbital craniotomy were obtained from our series of 5 patients who underwent a supraorbital approach for the resection of an OGM. The mean tumor volume was 54.6 cm 3 (range, 17-94.2 cm 3 ). Literature-reported rates of GTR (0.6) and CSF leak (0.3) with EEA were applied to our economic analysis. Supraorbital craniotomy was the preferred strategy, with an expected value of $29,423, compared with an EEA cost of $83,838. On multiple 1-way sensitivity analyses, supraorbital craniotomy remained the preferred strategy, with a minimum cost savings of $46,000 and a maximum savings of $64,000. Probabilistic sensitivity analysis found the lowest cost difference between the 2 surgical options to be $37,431., Conclusion: Compared with EEA, supraorbital craniotomy provides substantial cost savings in the treatment of OGMs. Given the potential differences in effectiveness between approaches, a cost-effectiveness analysis should be undertaken., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Sagittal balance in adult spinal deformity is a major predictor of quality of life. A temporary loss of paraspinal muscle force and somatic pain following spine surgery may limit a patient's ability to maintain posture., Objective: To assess the evolution of sagittal balance and clinical outcomes during recovery from adult spinal deformity surgery., Methods: Retrospective review of a prospective observational database identified a consecutive series of patients with sagittal vertical axis (SVA) > 40 mm undergoing adult deformity surgery. Radiographic parameters and clinical outcomes were measured out to 2 yr after surgery., Results: A total of 113 consecutive patients met inclusion criteria. Mean preoperative SVA was 90.3 mm, increased to 104.6 mm in the first week, then gradually reduced at each follow-up interval to 59.2 mm at 6 wk, 45.0 mm at 3 mo, 38.6 mm at 6 mo, and 34.1 mm at 1 yr (all P < .05). SVA did not change between 1 and 2 yr. Pelvic incidence-lumbar lordosis (PI-LL) corrected immediately from 25.3° to 8.5° (16.8° change; P < .01) and a decreased pelvic tilt from 27.6° to 17.6° (10° change; P < .01). No further change was noted in PI-LL. Pelvic tilt increased to 20.2° ( P = .01) at 6 wk and held steady through 2 yr. Mean Visual Analog Scale, Oswestry Disability Index, and Short Form-36 scores all improved; pain rapidly improved, whereas disability measures improved as SVA improved., Conclusion: Radiographic assessment of global sagittal alignment did not fully reflect surgical correction of sagittal balance until 6 mo after adult deformity surgery. Sagittal balance initially worsened then steadily improved at each interval over the first year postoperatively. At 1 yr, all clinical and radiographic measures outcomes were significantly improved., (Copyright © 2017 by the Congress of Neurological Surgeons)

Background: Annual incidence of symptomatic adjacent level disease (ALD) following lumbar fusion surgery ranges from 0.6% to 3.9% per year. Sagittal malalignment may contribute to the development of ALD., Objective: To describe the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and the development of symptomatic ALD requiring revision surgery following single-level transforaminal lumbar interbody fusion for degenerative lumbar spondylosis and/or low-grade spondylolisthesis., Methods: All patients who underwent a single-level transforaminal lumbar interbody fusion at either L4/5 or L5/S1 between July 2006 and December 2012 were analyzed for pre- and postoperative spinopelvic parameters. Using univariate and logistic regression analysis, we compared the spinopelvic parameters of those patients who required revision surgery against those patients who did not develop symptomatic ALD. We calculated the predictive value of PI-LL mismatch., Results: One hundred fifty-nine patients met the inclusion criteria. The results noted that, for a 1° increase in PI-LL mismatch (preop and postop), the odds of developing ALD requiring surgery increased by 1.3 and 1.4 fold, respectively, which were statistically significant increases. Based on our analysis, a PI-LL mismatch of >11° had a positive predictive value of 75% for the development of symptomatic ALD requiring revision surgery., Conclusions: A high PI-LL mismatch is strongly associated with the development of symptomatic ALD requiring revision lumbar spine surgery. The development of ALD may represent a global disease process as opposed to a focal condition. Spine surgeons may wish to consider assessment of spinopelvic parameters in the evaluation of degenerative lumbar spine pathology., (Copyright © 2017 by the Congress of Neurological Surgeons)

Objective: A retrospective review of the clinical and radiographic outcomes from a multicenter study of surgical treatment for high-grade spondylolisthesis (HGS) in adults. The objective was to assess the safety of surgical reduction, its ability to correct regional deformity, and its clinical effectiveness., Methods: Retrospective, multicenter review of adults (age above 18 y) with lumbosacral HGS (Meyerding grade 3-5) treated surgically with open decompression, attempted reduction, posterior instrumentation, and interbody fusion. Preoperative and postoperative assessment of the Meyerding grade, slip angle, and sacral inclination were performed based on standing radiographs. Preoperative visual analog scale scores were compared with those at the mean follow-up period. Prolo and Oswestry Disability Index scores at most recent follow-up were assessed., Results: A total of 25 patients, aged 19-72 years, met inclusion criteria. Seventeen interbody cages were placed, including 15 transforaminal lumbar interbody fusions, 1 posterior lumbar interbody fusion, and 1 anterior lumbar interbody fusion. Five patients required sacral dome osteotomies. The average follow-up was 21.3 months.At most recent follow-up there was a statistically significant improvement in both the Meyerding grade and the slip angle (P<0.05). There was 1 intraoperative complication resulting in a neurological deficit (4%) and 1 intraoperative vertebral body fracture (4%). No additional surgery was required for any of these patients. There were no cases of nonunion or device failure except for 1 patient who suffered an unrelated traumatic injury 1 year after surgery. The mean Oswestry Disability Index and Prolo scores at mean follow-up of 21.3 months were 20% (minimum disability) and 8.2 (grade 1), respectively., Conclusions: The present study suggests that reduction, when accomplished in conjunction with wide neural element decompression and instrumented arthrodesis, is safe, effective, and durable with low rates of neurological injury, favorable clinical results, and high-fusion rates.

Background: Balloon-assisted kyphoplasty (BAK) is a well-accepted treatment for symptomatic vertebral compression fractures (VCF) secondary to osteoporosis. Some have raised a concern of an increased incidence of adjacent fractures due to alterations in spine biomechanics after cement augmentation. The incidence of subsequent VCFs following BAK is poorly understood. The aim of this study was to investigate the timing, location, and incidence of new VCFs following BAK and to identify risk factors associated specifically with the occurrence of new adjacent level fractures., Objectives: The study was performed to determine the incidence of symptomatic subsequent adjacent and remote level compression fractures in a cohort of patients undergoing BAK., Study Design: Longitudinal cohort investigation at an academic medical center and a central referral center for VCFs., Setting: A consecutive single surgeon series of 726 patients with osteoporotic compression fractures., Methods: A prospectively collected cohort of 726 patients who underwent BAK between 2001 and 2014 for osteoporotic VCFs was evaluated. Seventy-seven patients were identified who underwent a second BAK for a new compression fracture and were include in the present series. The indication for BAK treatment was pain unresponsive to non-surgical management for all cases. Variables were recorded for each patient, including the time between index and subsequent fracture, fracture level, and number of initial fractures as well as with tobacco use, body mass index (BMI), and chronic steroid use., Results: Seventy-seven of 726 patients (10.6%) underwent a second BAK procedure on average 350 days following the initial procedure (range 21 to 2,691 days). Third and fourth procedures were less common, treated in 11 and 3 patients, respectively. Forty-eight of 77 patients (62%) suffered a fracture at a level immediately adjacent to the index level at mean time of 256 days. Remote level fractures were treated at a mean time of 489 days, but no statistical difference was noted. There was no statistically significant difference between tobacco use, BMI, and chronic steroid use between patients suffering from remote and adjacent level VCFs., Limitations: This was not a population based study, and the true incidence of subsequent fractures after BAK might be underestimated by this analysis., Conclusions: Symptomatic compression fractures after BAK are relatively uncommon and may occur long after the initial kyphoplasty procedure. Only half of subsequent fractures occur immediately adjacent to the initially treated level; the others occur remotely. Patients with a single symptomatic thoracic or lumbar fracture suffered from remote and adjacent level fractures equally. In contrast, all patients who suffered both a thoracic and lumbar fracture at the same time had a second fracture at an adjacent level. Specific risk factors for remote versus adjacent level fractures could not be determined. Key words: Balloon kyphoplasty, cement augmentation, osteoporosis, vertebral compression fracture, adjacent level fracture, vertebroplasty.

In deformity surgery, anterior lumbar interbody fusion provides excellent biomechanical support, creates a broad surface area for arthrodesis, and induces lordosis in the lower lumbar spine. Preoperative MRI, plain radiographs, and, when available, CT scan should be carefully assessed for sacral slope as it relates to pubic symphysis, position of the great vessels (especially at L4/5), disc space height, or contraindication to an anterior approach. This video demonstrates the steps in an anterior surgical procedure with minimal open exposure. The video can be found here: https://youtu.be/r3bC4&#95;vu1hQ .

While spinal epidural arteriovenous malformations, fistulas, and shunts are well reported, the presence of a venous malformation in the spinal epidural space is a rare phenomenon. Herein, the authors report the clinical presentation, imaging findings, pathological features, and the outcome of surgical and percutaneous interventional management of a mediastinal and spinal epidural venous malformation in a young woman who presented clinically with neurogenic claudication from presumed venous hypertension precipitating the formation of a syrinx. The patient underwent a C6-T5 osteoplastic laminectomy for decompression of the spinal canal and subtotal resection of the epidural venous malformation, followed by percutaneous sclerotherapy of the mediastinal and residual anterior spinal venous malformation. She developed transient loss of dorsal column sensation, which returned to baseline within 3 weeks of the surgery. A 6-month postoperative MRI study revealed complete resolution of the syrinx and the mediastinal venous malformation. Twelve months after the surgery, the patient has had resolution of all neurological symptoms with the exception of her premorbid migraine headaches. A multidisciplinary approach with partial resection and the use of percutaneous sclerotherapy for the residual malformation can be used to successfully treat a complex venous malformation.

Background: Direct cost comparisons between minimally invasive spine surgeries and the open options are rare., Objective: To compare healthcare costs associated with open transforaminal lumbar interbody fusion (TLIF) and minimally invasive lateral lumbar interbody fusion (LLIF) by calculating the incremental cost-effectiveness ratio (ICER) and to calculate the thresholds for minimum clinically important difference and minimum cost-effective difference for patient-reported outcome measures at the 2-year follow-up., Methods: Forty-five patients who underwent single-level TLIF and 29 patients who underwent single-level stand-alone LLIF were included in the comparison. All costs from diagnosis through the 2-year follow-up were available from a comprehensive single-center data bank within a unified hospital system. Payment provided for all spine-related medical resource use from the time of diagnosis through 2 years was recorded. A 0% discount rate was applied. Quality-adjusted life-years (QALYs) were calculated from the EuroQol-5D collected in an unbiased manner. Difference in total cost per QALY gained for LLIF minus that for TLIF was assessed as the estimate of the ICER from a US perspective., Results: Significant improvements were observed at the 2-year follow-up for both TLIF and LLIF with the Short Form-36 physical component summary, Oswestry Disability Index, visual analog scale back pain and leg pain scores, and EuroQol-5D. ICER calculations revealed similar mean cumulative QALYs gained at the 2-year interval (0.67 for TLIF and 0.60 for LLIF; P = .33). Median total costs of care after TLIF and LLIF were $44 068 and $45 574, respectively (P = .96). Minimum cost-effective difference thresholds with an anchor of <$50 000 per QALY were higher than minimum clinically important difference thresholds for all patient-reported outcome measures. Total mean cost and EuroQol-5D were statistically equivalent between the 2 treatment groups., Conclusion: TLIF and LLIF produced equivalent 2-year patient outcomes at an equivalent cost-effectiveness profile.

This prospective clinical study evaluated the use of a composite bone void filler (ChronOS Strip, DePuy Synthes, West Chester, PA, USA), combined with bone marrow aspirate plus local autologous bone, in a series of patients undergoing instrumented posterolateral spinal fusion with interbody support. Seventy-six patients were enrolled and treated per protocol at 13 clinical sites. At 24 months, 55/76 patients (72%) were evaluated, with 49/76 (65%) having sufficient data to determine the primary endpoint. The primary endpoint, posterolateral fusion success, was achieved in 48/54 (88.9%) patients at 12 months and in 45/49 (91.8%) patients at 24 months. At all follow-up time points, statistically significant improvements were observed when compared to baseline in back and leg pain and functional status as measured by visual analog scale, Oswestry Disability Index and 12-Item Short Form health surveys. This prospective multi-center series provides evidence that the composite bone void filler, when applied posterolaterally with instrumentation, bone marrow aspirate and/or local autologous bone and concomitant interbody support, can be used to achieve a successful posterolateral fusion, resulting in improvements in clinical outcomes in patients with degenerative disc disease., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Nutritional status is a critical factor in patient outcomes in a variety of medical contexts. In the surgical fields, there is substantial evidence suggesting that clinical outcomes including infection risk and surgical efficacy may be affected by preoperative nutritional status. The purpose of this study is to evaluate preoperative serum prealbumin levels, the currently preferred serum biomarker of nutritional deficiency, in relation to the risk of developing a surgical site infection., Methods: A retrospective case-control series was conducted comparing prospectively collected preadmission serum prealbumin levels to the risk for surgical site infection following elective spine surgery. The analysis was conducted under an approved institutional quality assurance protocol. Patients were identified by querying the department billing codes for deep wound washouts over a 3-year period. A cohort of 32 patients with preoperative prealbumin levels who underwent spine surgery complicated by postoperative deep tissue infection was identified. This was compared against a case-control cohort of 74 patients who underwent spine surgery and did not experience postoperative infection. Clinical variables included demographic information, body mass index, smoking, diabetes, steroid use, length of the procedure, and length of hospital stay. The data were analyzed using multivariate Cox regression., Results: Two variables: Preoperative prealbumin < 20 and diabetes were both statistically significant predictors for the risk of developing a postoperative infection with hazard ratios of 2.12 (95% confidence interval [CI]: 1.03-4.37) and 2.22 (95% CI: 1.04-4.75), respectively., Conclusions: Our results reinforce the relationship between preoperative nutritional status and outcomes in elective spine surgery. The data indicate that preoperative prealbumin levels may be useful in risk stratification. Further study is needed to determine whether nutritional supplementation may reduce the risk of infection.

Surgical site infections following the implantation of intrathecal drug delivery systems typically present during the first 1 to 2 months following surgery. Surgical site infections occurring outside of this window are rare entities and require special attention to identify the source or underlying cause. In this report, we present a case of pump pocket infection 18 months following implantation due to an asymptomatic and unrecognized bowel injury associated with the catheter. This case highlights the need for a thorough evaluation in a patient with suspected infections more than 2 months after surgery to ensure adequate treatment., (© 2015 World Institute of Pain.)

The authors report a unique case of a transosseous CSF fistula that was detected more than 10 years after treatment of a symptomatic Chiari I malformation. This lesion initially presented as an intraosseous cystic lesion involving the C-2 vertebra, which was found to communicate freely with the subarachnoid space through a tiny dural opening. Surgical management involved hemilaminectomy and repair of the dural defect followed by reinforcement of the bony defect with demineralized bone matrix. Following closure of the fistula, symptoms of elevated intracranial pressure developed, necessitating a ventriculoperitoneal shunt for CSF diversion.

Purpose: The LLIF procedure is a useful stand-alone and adjunct surgical approach for many spinal conditions. One complication of LLIF is subsidence of the interbody graft into the vertebral bodies, resulting in severe pain, impaired arthrodesis and potentially fracture of the body. Low bone density, as measured by T score on DEXA scanning, has also been postulated to increase the risk of subsidence., Methods: A retrospective review of prospectively collected data was performed on all patients who underwent LLIF at this institution consisting of 712 levels in 335 patients. Patients with subsidence following LLIF were recorded. We utilized the T score obtained from the femoral neck DEXA scans, which is used to determine overall fracture risk. The T score of patients with subsidence was compared to those without subsidence., Results: 20 of 57 (35 %) patients without subsidence had a DEXA T score between -1.0 and -2.4 consistent osteopenia, one patient (1.8 %) exhibited a T score less than -2.5, consistent with osteoporosis. 13 patients of 23 (57 %) with subsidence exhibited a T score between -1.0 and -2.4, consistent with osteopenia, five (22 %) exhibited a T score of -2.5 or less, consistent with osteoporosis. The mean DEXA T score in patients with subsidence was -1.65 (SD 1.04) compared to -0.45 (SD 0.97) in patients without subsidence (p < 0.01). The area under the receiver operating characteristic curve for patients with a T score of -1.0 or less was 80.1 %., Conclusions: Patients with DEXA T scores less than -1.0 who undergo stand-alone LLIF are at a much higher risk of developing graft subsidence. Further, they are at an increased risk of requiring additional surgery. In patients with poor bone quality, consideration could be made to supplement the LLIF cage with posterior instrumentation.

Purpose: Contemporary minimally invasive techniques have evolved to enable direct access to the anterior spinal column via the extreme lateral approach. We have employed this access approach to treat selected burst fractures. We report our technique. Thoracolumbar burst fractures that require surgical intervention have traditionally been managed with anterior, posterior, or combined approaches., Methods: We have applied the minimally invasive extreme lateral approach to perform vertebral corpectomy, cage placement, and lateral instrumentation to treat burst fractures. Indications for surgery were incomplete spinal cord injury with persistent neural element compression due to ventral fracture fragments in the canal. We present the technical nuances of this surgical approach for the treatment of thoracolumbar burst fractures with two case illustrations., Results: There were no peri- or intra-operative complications. Both patients in our series remained neurologically intact at their last follow-up (11 and 29 months, respectively), and maintained their correction of kyphosis., Conclusion: The minimally invasive extreme lateral approach is an effective treatment option for the management of thoracolumbar burst fractures.

Purpose: Available studies demonstrate vertebral body fractures as a relatively rare complication following lateral lumbar interbody fusion (LLIF), with most fractures reported in association with lateral plating and vertebral screws. This study reports the occurrence of two vertebral body fractures following stand-alone LLIF in 712 levels fused in 335 patients., Methods: A retrospective review of prospectively collected data was performed on all patients who underwent minimally invasive LLIF over a seven-year period at a single institution. Patients with vertebral body fractures were recorded., Results: Two patients (0.6 %) out of 335 total patients (712 levels) were identified with vertebral body fractures following stand-alone LLIF. Both patients presented with severe back pain and return of symptoms within 2 weeks of the index surgery. Both patients were obese, had impaired bone mineral density and were managed with open posterior segmental fixation., Conclusions: The 0.6 % incidence of vertebral body fractures in our series of fusing 712 levels is in accordance with the incidence rates reported in the literature. Potential risk factors for vertebral body fractures at the index LLIF level included obesity, osteopenia, unrecognized intraoperative endplate breach, graft subsidence and oversized graft placement.

Object: A hybrid approach of minimally invasive lateral lumbar interbody fusion (LLIF) followed by supplementary open posterior segmental instrumented fusion (PSIF) has shown promising early results in the treatment of adult degenerative scoliosis. Studies assessing the impact of this combined approach on correction of segmental and regional coronal angulation, sagittal realignment, maximum Cobb angle, restoration of lumbar lordosis, and clinical outcomes are needed. The authors report their results of this approach for correction of adult degenerative scoliosis., Methods: Twenty-six patients underwent combined LLIF and PSIF in a staged fashion. The patient population consisted of 21 women and 5 men. Ages ranged from 40 to 77 years old. Radiographic measurements including coronal angulation, pelvic incidence, lumbar lordosis, and sagittal vertical axis were taken preoperatively and 1 year postoperatively in all patients. Concurrently, the visual analog score (VAS) for back and leg pain, the Oswestry Disability Index (ODI), and Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were used to assess clinical outcomes in 19 patients., Results: At 1-year follow-up, all patients who underwent combined LLIF and PSIF achieved statistically significant mean improvement in regional coronal angles (from 14.9° to 5.8°, p < 0.01) and segmental coronal angulation at all operative levels (p < 0.01). The maximum Cobb angle was significantly reduced postoperatively (from 41.1° to 15.1°, p < 0.05) and was maintained at follow-up (12.0°, p < 0.05). The mean lumbar lordosis-pelvic incidence mismatch was significantly improved postoperatively (from 15.0° to 6.92°, p < 0.05). Although regional lumbar lordosis improved (from 43.0° to 48.8°), it failed to reach statistical significance (p = 0.06). The mean sagittal vertical axis was significantly improved postoperatively (from 59.5 mm to 34.2 mm, p < 0.01). The following scores improved significantly after surgery: VAS for back pain (from 7.5 to 4.3, p < 0.01) and leg pain (from 5.8 to 3.1, p < 0.01), ODI (from 48 to 38, p < 0.01), and PCS (from 27.5 to 35.0, p = 0.01); the MCS score did not improve significantly (from 43.2 to 45.5, p = 0.37). There were 3 major and 10 minor complications., Conclusions: A hybrid approach of minimally invasive LLIF and open PSIF is an effective means of achieving correction of both coronal and sagittal deformity, resulting in improvement of quality of life in patients with adult degenerative scoliosis.

We compared the histopathological features of the outer membrane of a chronic subdural hematoma (CSH) with its clinico-radiological presentation in patients. One hundred and fifty-six patients undergoing surgery for CSH were prospectively included in this study. Histopathological specimens of the outer neomembrane obtained intraoperatively were studied. Histological features were classified into four types and analyzed in relation to the Glasgow Coma Scale (GCS) score at presentation and radiological features. On histopathological examination, there were no cases of type I, 42.3% cases of type II and 34.6% cases of type III and 23.1% cases of types IV CSH neomembranes. Patients presenting with a GCS <13 exclusively had type II neomembranes. Increased radiodensity and thickness of the hematoma correlated with type IV neomembranes. This study may serve as an incentive to investigate the histopathology of CSH membranes in predicting outcomes and the recurrence of subdural hemorrhage after drainage surgery., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Since its inception in the year 2001 the minimally invasive trans-psoas Lateral Lumbar Interbody Fusion (LLIF) approach has gained significant favor among spine surgeons. It is now routinely utilized to treat an array of spinal pathologies including degenerative disc disease, low grade spondylolisthesis, and adult spinal deformity. The intent of this video is to provide a step by step account of the basic procedural details when performing the LLIF procedure for a single level broad based degenerated lumbar disc with herniation. The video can be found here: http://youtu.be/dZFMqmCz6Q8.

Object: In this paper the authors' goal was to investigate the clinical usefulness of Gd-enhanced MR ventriculography (MRV) in pediatric patients affected by multiloculated hydrocephalus., Methods: Eighteen patients (11 boys and 7 girls, age range 2-14 months) with a diagnosis of multiloculated hydrocephalus were included in the study. After injection of gadodiamide (0.02-0.04 mmol) into the lateral ventricle by tapping the anterior fontanel, sagittal, coronal, and axial T1-weighted MR images were acquired. The location of the septations and the sites of obstruction of CSF flow were assessed. Postoperative MRV was obtained to confirm the results of endoscopic treatment in most complex cases., Results: No adverse events were observed after injection of contrast medium into the ventricular system. Preoperative MRV accurately defined the exact morphology of septae and ventricular walls in all cases. In 1 case the diagnosis of multiloculated hydrocephalus was ruled out. Sites of obstruction of CSF flow within the ventricular system were also well established. In 4 cases the multiple compartments were proven to intercommunicate. Postoperative MRV was useful in assessing the functional status of third ventriculostomy, aqueductoplasty, and other endoscopic fenestrations., Conclusions: Magnetic resonance ventriculography is a safe, effective, and reliable technique. The accurate definition of the anatomy of the ventricles and the site of obstruction in multiloculated hydrocephalus can help to plan the most appropriate treatment and minimize the number of procedures. Although MRV is also useful during postoperative follow-up to determine the results of endoscopic treatment, it should be limited to particularly complex cases, due to its invasiveness.