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William T. Couldwell, Joel D. MacDonald, Charles L. Thomas, Bradley C. Hansen, Aniruddha Lapalikar, Bharat Thakkar, and Alagar K. Balaji

The authors have developed a simple device for computer-aided design/computer-aided manufacturing (CAD-CAM) that uses an image-guided system to define a cutting tool path that is shared with a surgical machining system for drilling bone. Information from 2D images (obtained via CT and MRI) is transmitted to a processor that produces a 3D image. The processor generates code defining an optimized cutting tool path, which is sent to a surgical machining system that can drill the desired portion of bone. This tool has applications for bone removal in both cranial and spine neurosurgical approaches. Such applications have the potential to reduce surgical time and associated complications such as infection or blood loss. The device enables rapid removal of bone within 1 mm of vital structures. The validity of such a machining tool is exemplified in the rapid (< 3 minutes machining time) and accurate removal of bone for transtemporal (for example, translabyrinthine) approaches.

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Ehud Mendel, Narendra Nathoo, Thomas Scharschmidt, Carl Schmidt, James Boehmler, and Joel L. Mayerson

En bloc resection with negative tumor margins remains the principal treatment option for control or cure of primary pelvic chondrosarcomas, as current adjuvant therapies remain ineffective. Iliosacral chondrosarcomas with involvement of the sciatic notch are sufficiently challenging tumors. However, when there is concomitant lumbar extension requiring resection of the pedicles to maintain negative surgical margins, transpedicular screw fixation is not possible, making reconstruction of the lumbopelvic junction extremely challenging. A patient with an iliosacral chondrosarcoma with lumbar spine extension is presented in this report to illustrate a novel lumbopelvic spinal construct. Following combined external pelvectomy and hemisacrectomy with contralateral L3–5 hemilaminectomy and ipsilateral pediculotomy, bicortical transvertebral body screws were substituted for the missing pedicles, resulting in the creation of “false pedicles,” which were further supplemented with an autologous vascularized fibular strut graft from the amputated lower limb and applied to the lateral aspect of the vertebral bodies. The creation of false pedicles allowed for a robust reconstruction of the lumbopelvic junction, including maintaining pelvic ring integrity with a “neo-pelvis”, creating a functional load-bearing construct adequate for early mobilization and ambulation. The biomechanical dynamics of this unique construct are also discussed.

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Dennis London, Ben Birkenfeld, Joel Thomas, Marat Avshalumov, Alon Y. Mogilner, Steven Falowski, and Antonios Mammis

OBJECTIVE

The human myotome is fundamental to the diagnosis and treatment of neurological disorders. However, this map was largely constructed decades ago, and its breadth, variability, and reliability remain poorly described, limiting its practical use.

METHODS

The authors used a novel method to reconstruct the myotome map in patients (n = 42) undergoing placement of dorsal root ganglion electrodes for the treatment of chronic pain. They electrically stimulated nerve roots (n = 79) in the intervertebral foramina at T12–S1 and measured triggered electromyography responses.

RESULTS

L4 and L5 stimulation resulted in quadriceps muscle (62% and 33% of stimulations, respectively) and tibialis anterior (TA) muscle (25% and 67%, respectively) activation, while S1 stimulation resulted in gastrocnemius muscle activation (46%). However, L5 and S1 both resulted in abductor hallucis (AH) muscle activation (17% and 31%), L5 stimulation resulted in gastrocnemius muscle stimulation (42%), and S1 stimulation in TA muscle activation (38%). The authors also mapped the breadth of the myotome in individual patients, finding coactivation of adductor and quadriceps, quadriceps and TA, and TA and gastrocnemius muscles under L3, L4, and both L5 and S1 stimulation, respectively. While the AH muscle was commonly activated by S1 stimulation, this rarely occurred together with TA or gastrocnemius muscle activation. Other less common coactivations were also observed throughout T12–S1 stimulation.

CONCLUSIONS

The muscular innervation of the lumbosacral nerve roots varies significantly from the classic myotome map and between patients. Furthermore, in individual patients, each nerve root may innervate a broader range of muscles than is commonly assumed. This finding is important to prevent misdiagnosis of radicular pathologies.

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David C. Perry, Virginia E. Sturm, Matthew J. Peterson, Carl F. Pieper, Thomas Bullock, Bradley F. Boeve, Bruce L. Miller, Kevin M. Guskiewicz, Mitchel S. Berger, Joel H. Kramer, and Kathleen A. Welsh-Bohmer

OBJECT

Mild traumatic brain injury (TBI) has been proposed as a risk factor for the development of Alzheimer’s disease, Parkinson’s disease, depression, and other illnesses. This study’s objective was to determine the association of prior mild TBI with the subsequent diagnosis (that is, at least 1 year postinjury) of neurological or psychiatric disease.

METHODS

All studies from January 1995 to February 2012 reporting TBI as a risk factor for diagnoses of interest were identified by searching PubMed, study references, and review articles. Reviewers abstracted the data and assessed study designs and characteristics.

RESULTS

Fifty-seven studies met the inclusion criteria. A random effects meta-analysis revealed a significant association of prior TBI with subsequent neurological and psychiatric diagnoses. The pooled odds ratio (OR) for the development of any illness subsequent to prior TBI was 1.67 (95% CI 1.44–1.93, p < 0.0001). Prior TBI was independently associated with both neurological (OR 1.55, 95% CI 1.31–1.83, p < 0.0001) and psychiatric (OR 2.00, 95% CI 1.50–2.66, p < 0.0001) outcomes. Analyses of individual diagnoses revealed higher odds of Alzheimer’s disease, Parkinson’s disease, mild cognitive impairment, depression, mixed affective disorders, and bipolar disorder in individuals with previous TBI as compared to those without TBI. This association was present when examining only studies of mild TBI and when considering the influence of study design and characteristics. Analysis of a subset of studies demonstrated no evidence that multiple TBIs were associated with higher odds of disease than a single TBI.

CONCLUSIONS

History of TBI, including mild TBI, is associated with the development of neurological and psychiatric illness. This finding indicates that either TBI is a risk factor for heterogeneous pathological processes or that TBI may contribute to a common pathological mechanism.

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Daniel H. Fulkerson, Ian K. White, Jacqueline M. Rees, Maraya M. Baumanis, Jodi L. Smith, Laurie L. Ackerman, Joel C. Boaz, and Thomas G. Luerssen

OBJECT

Patients with traumatic brain injury (TBI) with low presenting Glasgow Coma Scale (GCS) scores have very high morbidity and mortality rates. Neurosurgeons may be faced with difficult decisions in managing the most severely injured (GCS scores of 3 or 4) patients. The situation may be considered hopeless, with little chance of a functional recovery. Long-term data are limited regarding the clinical outcome of children with severe head injury. The authors evaluate predictor variables and the clinical outcomes at discharge, 1 year, and long term (median 10.5 years) in a cohort of children with TBI presenting with postresuscitation GCS scores of 3 and 4.

METHODS

A review of a prospectively collected trauma database was performed. Patients treated at Riley Hospital for Children (Indianapolis, Indiana) from 1988 to 2004 were reviewed. All children with initial GCS (modified for pediatric patients) scores of 3 or 4 were identified. Patients with a GCS score of 3 were compared with those with a GCS score of 4. The outcomes of all patients at the time of death or discharge and at 1-year and long-term follow-up were measured with a modified Glasgow Outcome Scale (GOS) that included a “normal” outcome. Long-term outcomes were evaluated by contacting surviving patients. Statistical "classification trees" were formed for survival and outcome, based on predictor variables.

RESULTS

Sixty-seven patients with a GCS score of 3 or 4 were identified in a database of 1636 patients (4.1%). Three of the presenting factors differed between the GCS 3 patients (n = 44) and the GCS 4 patients (n = 23): presence of hypoxia, single seizure, and open basilar cisterns on CT scan. The clinical outcomes were statistically similar between the 2 groups. In total, 48 (71.6%) of 67 patients died, remained vegetative, or were severely disabled by 1 year. Eight patients (11.9%) were normal at 1 year. Ten of the 22 patients with long-term follow-up were either normal or had a GOS score of 5.

Multiple clinical, historical, and radiological factors were analyzed for correlation with survival and clinical outcome. Classification trees were formed to stratify predictive factors. The pupillary response was the factor most predictive of both survival and outcome. Other factors that either positively or negatively correlated with survival included hypothermia, mechanism of injury (abuse), hypotension, major concurrent symptoms, and midline shift on CT scan. Other factors that either positively or negatively predicted long-term outcome included hypothermia, mechanism of injury, and the assessment of the fontanelle.

CONCLUSIONS

In this cohort of 67 TBI patients with a presenting GCS score of 3 or 4, 56.6% died within 1 year. However, approximately 15% of patients had a good outcome at 10 or more years. Factors that correlated with survival and outcome included the pupillary response, hypothermia, and mechanism. The authors discuss factors that may help surgeons make critical decisions regarding their most serious pediatric trauma patients.

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Regina I. Jakacki, Bruce H. Cohen, Cheryl Jamison, Vincent P. Mathews, Edward Arenson, Darryl C. Longee, Joanne Hilden, Al Cornelius, Michael Needle, Doug Heilman, Joel C. Boaz, and Thomas G. Luerssen

Object. Craniopharyngiomas originate from the same cells as squamous cell skin carcinoma, which can be treated successfully with interferon-α (IFNα)-2a. The authors evaluated the activity and toxicity of systemic IFN in young patients with craniopharyngiomas.

Methods. Fifteen patients between the ages of 4.2 and 19.8 years who had progressive or recurrent craniopharyngiomas were enrolled in this study. Nine of these patients had never received external-beam radiation therapy. Therapy consisted of 8,000,000 U/m2 IFNα-2a administered daily for 16 weeks (induction phase) followed by the same dose three times per week for an additional 32 weeks (maintenance phase). Of the 12 patients who could be evaluated, radiological studies demonstrated a response to treatment in three with predominantly cystic tumors (one minor response, one partial response, and one complete response); one of these patients also showed improvement in visual fields. The size of the cystic component of the tumors often increased temporarily during the first several months of therapy. Three patients met the criteria for progressive disease during therapy. The median time to progression was 25 months. The need for radiation therapy in patients treated with IFN was delayed for 18 to 35 months (median 25 months) in six patients. All patients developed transient flulike symptoms shortly after receiving the first dose of IFN. Other toxicities (predominantly hepatic, neurological, and cutaneous) were seen in nine (60%) of the 15 patients during the first 8 weeks of treatment but resolved after temporary discontinuation and/or dose reduction.

Conclusions. Interferon-α-2a is active against some childhood craniopharyngiomas; its toxicity precludes administration of high daily doses, and the optimum dose level and schedule remain to be defined.

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Leslie N. Sutton, Patricia T. Molloy, Heidi Sernyak, Joel Goldwein, Peter L. Phillips, Lucy B. Rorke, Thomas Moshang Jr., Beverly Lange, and Roger J. Packer

✓ The feasibility of radical surgery for astrocytomas of the optic chiasm/hypothalamus has been reported by several groups. Such surgery carries significant risks, however, including permanent damage to the pituitary gland, optic apparatus, hypothalamic structures, and carotid arteries. The benefits of radical surgery, both in terms of efficacy and toxicity, should, therefore, be evaluated against standard therapy, as is usually done for new chemotherapeutic protocols.

To this end, a retrospective review was performed of 33 patients treated at Children's Hospital of Philadelphia between 1976 and 1991 who met criteria that would have made them eligible for radical surgery in many centers today, but were treated with either no surgery or conservative surgery (< 50% resection) or biopsy followed by adjuvant therapy with local radiation therapy (29 patients) and/or chemotherapy with actinomycin-D and vincristine (18 patients). The review encompassed all children with a globular enhancing mass of at least 2 cm in the hypothalamic/chiasmatic region, no evidence of optic nerve involvement or involvement of the optic radiations by computerized tomography or magnetic resonance imaging, and follow up of at least 3 years. All but one patient had tissue confirmation of a low-grade or pilocytic astrocytoma. Thirteen of the patients were 2 years of age or younger at diagnosis.

Five individuals died: three of tumor progression, one of acute shunt malfunction, and one of intercurrent infection. The remaining 28 were alive at last follow up, a mean of 10.9 years from diagnosis. Twenty-three surviving patients have functional vision in at least one eye, 12 require no endocrine replacement, and 16 are in or have completed schooling with regular academic requirements.

If radical surgery is to become standard care for children with low-grade astrocytomas of the hypothalamic/chiasmatic region, long-term survival and functional outcome will have to equal or surpass those of historical controls who were treated conservatively.

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Bornali Kundu, Amy Penwarden, Joel M. Wood, Thomas A. Gallagher, Matthew J. Andreoli, Jed Voss, Timothy Meier, Veena A. Nair, John S. Kuo, Aaron S. Field, Chad Moritz, M. Elizabeth Meyerand, and Vivek Prabhakaran

Object

Functional MRI (fMRI) has the potential to be a useful presurgical planning tool to treat patients with primary brain tumor. In this study the authors retrospectively explored relationships between language-related postoperative outcomes in such patients and multiple factors, including measures estimated from task fMRI maps (proximity of lesion to functional activation area, or lesion-to-activation distance [LAD], and activation-based language lateralization, or lateralization index [LI]) used in the clinical setting for presurgical planning, as well as other factors such as patient age, patient sex, tumor grade, and tumor volume.

Methods

Patient information was drawn from a database of patients with brain tumors who had undergone preoperative fMRI-based language mapping of the Broca and Wernicke areas. Patients had performed a battery of tasks, including word-generation tasks and a text-versus-symbols reading task, as part of a clinical fMRI protocol. Individually thresholded task fMRI activation maps had been provided for use in the clinical setting. These clinical imaging maps were used to retrospectively estimate LAD and LI for the Broca and Wernicke areas.

Results

There was a relationship between postoperative language deficits and the proximity between tumor and Broca area activation (the LAD estimate), where shorter LADs were related to the presence of postoperative aphasia. Stratification by tumor location further showed that for posterior tumors within the temporal and parietal lobes, more bilaterally oriented Broca area activation (LI estimate close to 0) and a shorter Wernicke area LAD were associated with increased postoperative aphasia. Furthermore, decreasing LAD was related to decreasing LI for both Broca and Wernicke areas. Preoperative deficits were related to increasing patient age and a shorter Wernicke area LAD.

Conclusions

Overall, LAD and LI, as determined using fMRI in the context of these paradigms, may be useful indicators of postsurgical outcomes. Whereas tumor location may influence postoperative deficits, the results indicated that tumor proximity to an activation area might also interact with how the language network is affected as a whole by the lesion. Although the derivation of LI must be further validated in individual patients by using spatially specific statistical methods, the current results indicated that fMRI is a useful tool for predicting postoperative outcomes in patients with a single brain tumor.

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Oliver G. S. Ayling, Raphaele Charest-Morin, Matthew E. Eagles, Tamir Ailon, John T. Street, Nicolas Dea, Greg McIntosh, Sean D. Christie, Edward Abraham, W. Bradley Jacobs, Christopher S. Bailey, Michael G. Johnson, Najmedden Attabib, Peter Jarzem, Michael Weber, Jerome Paquet, Joel Finkelstein, Alexandra Stratton, Hamilton Hall, Neil Manson, Y. Raja Rampersaud, Kenneth Thomas, and Charles G. Fisher

OBJECTIVE

Previous works investigating rates of adverse events (AEs) in spine surgery have been retrospective, with data collection from administrative databases, and often from single centers. To date, there have been no prospective reports capturing AEs in spine surgery on a national level, with comparison among centers.

METHODS

The Spine Adverse Events Severity system was used to define the incidence and severity of AEs after spine surgery by using data from the Canadian Spine Outcomes and Research Network (CSORN) prospective registry. Patient data were collected prospectively and during hospital admission for those undergoing elective spine surgery for degenerative conditions. The Spine Adverse Events Severity system defined minor and major AEs as grades 1–2 and 3–6, respectively.

RESULTS

There were 3533 patients enrolled in this cohort. There were 85 (2.4%) individual patients with at least one major AE and 680 (19.2%) individual patients with at least one minor AE. There were 25 individual patients with 28 major intraoperative AEs and 260 patients with 275 minor intraoperative AEs. Postoperatively there were 61 patients with a total of 80 major AEs. Of the 487 patients with minor AEs postoperatively there were 698 total AEs. The average enrollment was 321 patients (range 47–1237 patients) per site. The rate of major AEs was consistent among sites (mean 2.9% ± 2.4%, range 0%–9.1%). However, the rate of minor AEs varied widely among sites—from 7.9% to 42.5%, with a mean of 18.8% ± 9.7%. The rate of minor AEs varied depending on how they were reported, with surgeon reporting associated with the lowest rates (p < 0.01).

CONCLUSIONS

The rate of major AEs after lumbar spine surgery is consistent among different sites but the rate of minor AEs appears to vary substantially. The method by which AEs are reported impacts the rate of minor AEs. These data have implications for the detection and reporting of AEs and the design of strategies aimed at mitigating complications.

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Oliver G. S. Ayling, Y. Raja Rampersaud, Charlotte Dandurand, Po Hsiang (Shawn) Yuan, Tamir Ailon, Nicolas Dea, Greg McIntosh, Sean D. Christie, Edward Abraham, Christopher S. Bailey, Michael G. Johnson, Jacques Bouchard, Michael H. Weber, Jerome Paquet, Joel Finkelstein, Alexandra Stratton, Hamilton Hall, Neil Manson, Kenneth Thomas, and Charles G. Fisher

OBJECTIVE

Treatment of degenerative lumbar diseases has been shown to be clinically effective with open transforaminal lumbar interbody fusion (O-TLIF) or minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Despite this, a substantial proportion of patients do not meet minimal clinically important differences (MCIDs) in patient-reported outcomes (PROs). The objectives of this study were to compare the proportions of patients who did not meet MCIDs after O-TLIF and MIS-TLIF and to determine potential clinical factors associated with failure to achieve MCID.

METHODS

The authors performed a retrospective analysis of consecutive patients who underwent O-TLIF or MIS-TLIF for lumbar degenerative disorders and had been prospectively enrolled in the Canadian Spine Outcomes and Research Network. The authors analyzed the Oswestry Disability Index (ODI) scores, physical and mental component summary scores of SF-12, numeric rating scale (NRS) scores for leg and back pain, and EQ-5D scores of the patients in each group who did not meet the MCID of ODI at 2 years postoperatively.

RESULTS

In this study, 38.8% (137 of 353) of patients in the O-TLIF cohort and 41.8% (51 of 122) of patients in the MIS-TLIF cohort did not meet the MCID of ODI at 2 years postoperatively (p = 0.59). Demographic variables and baseline PROs were similar between groups. There were improvements across the PROs of both groups through 2 years, and there were no differences in any PROs between the O-TLIF and MIS-TLIF cohorts. Multivariable logistic regression analysis demonstrated that higher baseline leg pain score (p = 0.017) and a diagnosis of spondylolisthesis (p = 0.0053) or degenerative disc disease (p = 0.022) were associated with achieving the MCID at 2 years after O-TLIF, whereas higher baseline leg pain score was associated with reaching the MCID after MIS-TLIF (p = 0.038).

CONCLUSIONS

Similar proportions of patients failed to reach the MCID of ODI at 2 years after O-TLIF or MIS-TLIF. Higher baseline leg pain score was predictive of achieving the MCID in both cohorts, whereas a diagnosis of spondylolisthesis or degenerative disc disease was predictive of reaching the MCID after O-TLIF. These data provide novel insights for patient counseling and suggest that either MIS-TLIF or O-TLIF does not overcome specific patient factors to mitigate clinical success or failure in terms of the intermediate-term PROs associated with 1- to 2-level lumbar fusion surgical procedures for degenerative pathologies.