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Deshpande V. Rajakumar, Akshay Hari, Murali Krishna, Subhas Konar and Ankit Sharma

OBJECTIVE

Adjacent-level disc degeneration following cervical fusion has been well reported. This condition poses a major treatment dilemma when it becomes symptomatic. The potential application of cervical arthroplasty to preserve motion in the affected segment is not well documented, with few studies in the literature. The authors present their initial experience of analyzing clinical and radiological results in such patients who were treated with arthroplasty for new or persistent arm and/or neck symptoms related to neural compression due to adjacent-segment disease after anterior cervical discectomy and fusion (ACDF).

METHODS

During a 5-year period, 11 patients who had undergone ACDF anterior cervical discectomy and fusion (ACDF) and subsequently developed recurrent neck or arm pain related to adjacent-level cervical disc disease were treated with cervical arthroplasty at the authors' institution. A total of 15 devices were implanted (range of treated levels per patient: 1–3).

Clinical evaluation was performed both before and after surgery, using a visual analog scale (VAS) for pain and the Neck Disability Index (NDI). Radiological outcomes were analyzed using pre- and postoperative flexion/extension lateral radiographs measuring Cobb angle (overall C2–7 sagittal alignment), functional spinal unit (FSU) angle, and range of motion (ROM).

RESULTS

There were no major perioperative complications or device-related failures. Statistically significant results, obtained in all cases, were reflected by an improvement in VAS scores for neck/arm pain and NDI scores for neck pain. Radiologically, statistically significant increases in the overall lordosis (as measured by Cobb angle) and ROM at the treated disc level were observed. Three patients were lost to follow-up within the first year after arthroplasty. In the remaining 8 cases, the duration of follow-up ranged from 1 to 3 years. None of these 8 patients required surgery for the same vertebral level during the follow-up period.

CONCLUSIONS

Artificial cervical disc replacement in patients who have previously undergone cervical fusion surgery appears to be safe, with encouraging early clinical results based on this small case series, but more data from larger numbers of patients with long-term follow-up are needed. Arthroplasty may provide an additional tool for the management of post-fusion adjacent-level cervical disc disease in carefully selected patients.

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Deshpande Rajakumar, Ankit Sharma, Akshay Hari, Subhas Konar and Murali Krishna

Cervical arthroplasty is being recognized as an emerging alternative to anterior cervical fusion with comparable or superior outcomes. The authors describe the surgical nuances of 2-level cervical arthroplasty in a case of 2-level degenerative disease. In this surgical technique, conventional vertebral body distraction has been avoided to prevent facet distraction, which can be a cause of persistent postoperative neck pain. Good motion preservation was observed at the 1-year follow-up examination.

The video can be found here: https://youtu.be/YTpRVRXuZZk.

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Anil Nanda, Subhas Konar, Piyush Kalakoti and Tanmoy Maiti

Owing to a deep-seated location and intricate venous anatomy, pathologies of the posterior third ventricular region pose formidable challenges to the operating neurosurgeon. In this video, we present a case of an elderly Caucasian female with a rare histological variant of a pineal parenchymal mass who presented with gait disturbances and worsening retro-orbital headache. Radiological and clinco-histopathological correlates of this rare tumor pathology having intermediate differentiation are highlighted. Briefly outlined are surgical pearls and strategies to minimize complications, as the tumor is approached through the posterior interhemispheric corridor, to achieve a gross-total decompression.

The video can be found here: https://youtu.be/KXwclZ7Ei84.

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Anil Nanda, Subhas Konar, Piyush Kalakoti and Tanmoy Maiti

Of the posterior third ventricular tumors, a papillary tumor of the pineal gland is a rare entity that originates from specialized ependymoma of the subcommissural organ. In this video narration, we present a case of a 33-year-old male with headaches and recent cognitive decline due to a posterior third ventricular lesion. The patient underwent a posterior interhemispheric approach, and a gross-total decompression was achieved with no signs of recurrence in a 2-year follow-up period. With this case we highlight the microsurgical technique employed for decompressing tumors of the posterior third ventricular region with preservation of eloquent structures and draining veins.

The video can be found here:https://youtu.be/o0WbyOqmtX0.

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Shyamal C. Bir, Subhas Konar, Tanmoy Maiti, Anil Nanda and Bharat Guthikonda

OBJECTIVE

Spinal cord stimulators (SCSs) appear to be safe and efficacious for chronic intractable back pain. Although there are many reports on percutaneous SCSs, there are very few studies on outcomes of paddle lead SCSs. In addition, the predictors of requirement for SCS revision have not been well established. Here, the authors review the outcome of a case series and attempt to identify the predictors of SCS revisions.

METHODS

The clinical and radiological information of 141 patients with intractable chronic pain who underwent SCS implantation within the past 20 years was retrospectively reviewed. Paddle lead SCSs were used in this series. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression.

RESULTS

Among 141 cases, 90 (64%) did not require any revision after SCS implantations. Removal of the SCS was required in 14 patients. The average pain score was significantly reduced (preimplantation score of 8 vs postimplantation score of 1.38; p < 0.0001). Younger age, male sex, obesity, a preimplantation pain score ≥ 8, and the presence of neuromuscular pain were identified as predictors of the overall requirement for SCS revision. However, only a preimplantation pain score ≥ 8 was identified as a predictor of early failure of the SCS.

CONCLUSIONS

Implantation of a paddle lead SCS is a relatively less invasive, safe, and effective procedure for patients with intractable back pain. Revision of the procedure depends on many factors, including younger age, male sex, associated neuromuscular pain, and severity of the pain. Therefore, patients with these factors, for whom implantation of an SCS is planned, should be closely followed for the possible requirement for revision.

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Piyush Kalakoti, Symeon Missios, Richard Menger, Sunil Kukreja, Subhas Konar and Anil Nanda

OBJECT

Because of the limited data available regarding the associations between risk factors and the effect of hospital case volume on outcomes after resection of intradural spine tumors, the authors attempted to identify these associations by using a large population-based database.

METHODS

Using the National Inpatient Sample database, the authors performed a retrospective cohort study that involved patients who underwent surgery for an intradural spinal tumor between 2002 and 2011. Using national estimates, they identified associations of patient demographics, medical comorbidities, and hospital characteristics with inpatient postoperative outcomes. In addition, the effect of hospital volume on unfavorable outcomes was investigated. Hospitals that performed fewer than 14 resections in adult patients with an intradural spine tumor between 2002 and 2011 were labeled as low-volume centers, whereas those that performed 14 or more operations in that period were classified as high-volume centers (HVCs). These cutoffs were based on the median number of resections performed by hospitals registered in the National Inpatient Sample during the study period.

RESULTS

Overall, 18,297 patients across 774 hospitals in the United States underwent surgery for an intradural spine tumor. The mean age of the cohort was 56.53 ± 16.28 years, and 63% were female. The inpatient postoperative risks included mortality (0.3%), discharge to rehabilitation (28.8%), prolonged length of stay (> 75th percentile) (20.0%), high-end hospital charges (> 75th percentile) (24.9%), wound complications (1.2%), cardiac complications (0.6%), deep vein thrombosis (1.4%), pulmonary embolism (2.1%), and neurological complications, including durai tears (2.4%). Undergoing surgery at an HVC was significantly associated with a decreased chance of inpatient mortality (OR 0.39; 95% CI 0.16−0.98), unfavorable discharge (OR 0.86; 95% CI 0.76−0.98), prolonged length of stay (OR 0.69; 95% CI 0.62−0.77), high-end hospital charges (OR 0.67; 95% CI 0.60−0.74), neurological complications (OR 0.34; 95% CI 0.26−0.44), deep vein thrombosis (OR 0.65; 95% CI 0.45−0.94), wound complications (OR 0.59; 95% CI 0.41−0.86), and gastrointestinal complications (OR 0.65; 95% CI 0.46−0.92).

CONCLUSIONS

The results of this study provide individualized estimates of the risks of postoperative complications based on patient demographics and comorbidities and hospital characteristics and shows a decreased risk for most unfavorable outcomes for those who underwent surgery at an HVC. These findings could be used as a tool for risk stratification, directing presurgical evaluation, assisting with surgical decision making, and strengthening referral systems for complex cases.

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Subhas K. Konar, Shyamal C. Bir, Tanmoy K. Maiti and Anil Nanda

OBJECTIVE

The incidence of primary spinal cord glioblastoma multiforme (GBM) in the pediatric age group is very rare. Only a few case series and case reports have been published in the literature; therefore, overall survival (OS) outcome and the as-yet poorly defined management options are not discussed in detail. The authors performed a cumulative survival analysis of all reported cases of pediatric spinal cord GBM to identify the predictive factors related to final survival outcome.

METHODS

A comprehensive search for relevant articles was performed on PubMed's electronic database MEDLINE for the period from 1950 to 2015 using the search words “malignant spinal cord tumor” and “spinal glioblastoma multiforme.” This study was limited to patients younger than 18 years of age. Survival rates for children with various tumor locations and treatments were collected from the published articles and analyzed.

RESULTS

After an extensive literature search, 29 articles met the study inclusion criteria. From the detailed information in these articles, the authors found 53 children eligible for the survival analysis. The majority (45%) of the children were more than 12 years old. Thirty-four percent of the cases were between 7 and 12 years of age, and 21% were younger than 7 years. In the Kaplan-Meier survival analysis, children younger than 7 years of age had better survival (13 months) than the children older than 7 years (7–12 years: 10 months, > 12 years: 9 months; p = 0.01, log-rank test). Fifty-five percent of the children were female and 45% were male. A cervical tumor location (32%) was the most common, followed by thoracic (28.3%). Cervicothoracic (18.9%) and conus (18.8%) tumor locations shared the same percentage of cases. Cervical tumors had a worse outcome than tumors in other locations (p = 0.003, log-rank test). The most common presenting symptom was limb weakness (53%), followed by sensory disturbances (25%). Median OS was 10 months. The addition of adjuvant therapy (radiotherapy [RT] and/or chemotherapy [CT]) after surgery significantly improved OS (p = 0.01, log-rank test). Children who underwent gross-total resection and RT had better outcomes than those who underwent subtotal resection and RT (p = 0.04, log-rank test). Cerebrospinal fluid spread, hydrocephalus, brain metastasis, and spinal metastasis were not correlated with OS in primary spinal GBM.

CONCLUSIONS

Adjuvant therapy after surgery had a beneficial effect on overall outcome of spinal GBM in the pediatric age group. Gross-total resection followed by RT produced a better outcome than subtotal resection with RT. Further large-scale prospective study is required to establish the genetic and molecular factors related to OS in primary GBM of the spinal cord in pediatric patients.

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Tanmoy Kumar Maiti, Subhas Konar, Shyamal Bir, Piyush Kalakoti, Papireddy Bollam and Anil Nanda

OBJECT

The difference in course and outcome of several neurodegenerative conditions and traumatic injuries of the nervous system points toward a possible role of genetic and environmental factors as prognostic markers. Apolipoprotein E (Apo-E), a key player in lipid metabolism, is recognized as one of the most powerful genetic risk factors for dementia and other neurodegenerative diseases. In this article, the current understanding of APOE polymorphism in various neurological disorders is discussed.

METHODS

The English literature was searched for various studies describing the role of APOE polymorphism as a prognostic marker in neurodegenerative diseases and traumatic brain injury. The wide ethnic distribution of APOE polymorphism was discussed, and the recent meta-analyses of role of APOE polymorphism in multiple diseases were analyzed and summarized in tabular form.

RESULTS

Results from the review of literature revealed that the distribution of APOE is varied in different ethnic populations. APOE polymorphism plays a significant role in pathogenesis of neurodegeneration, particularly in Alzheimer’s disease. APOE ε4 is considered a marker for poor prognosis in various diseases, but APOE ε2 rather than APOE ε4 has been associated with cerebral amyloid angiopathy-related bleeding and sporadic Parkinson’s disease. The role of APOE polymorphism in various neurological diseases has not been conclusively elucidated.

CONCLUSIONS

Apo-E is a biomarker for various neurological and systemic diseases. Therefore, while analyzing the role of APOE polymorphism in neurological diseases, the interpretation should be done after adjusting all the confounding factors. A continuous quest to look for associations with various neurological diseases and wide knowledge of available literature are required to improve the understanding of the role of APOE polymorphism in these conditions and identify potential therapeutic targets.

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Subhas K. Konar, Shyamal C. Bir, Tanmoy K. Maiti, Papireddy Bollam and Anil Nanda

Isadore Max Tarlov, an early neurosurgeon, made several important contributions to the field of spine surgery. He described sacral perineural cysts, now known as Tarlov cysts. Dr. Tarlov also introduced the knee-chest patient position to facilitate exposure and hemostasis in lumbar surgery. In addition, he developed the use of fibrin glue in nerve repair. His book on mechanisms of spinal compression was published in 1957. He published a book of essays titled Principles of Parsimony in Medical Practice that remains highly relevant in today's medical world.

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Anil Nanda, Shyamal C. Bir, Tanmoy K. Maiti, Subhas K. Konar, Symeon Missios and Bharat Guthikonda

OBJECTIVE

The clinical significance of the Simpson system for grading the extent of meningioma resection and its role as a predictor of the recurrence of World Health Organization (WHO) Grade I meningiomas have been questioned in the past, echoing changes in meningioma surgery over the years. The authors reviewed their experience in resecting WHO Grade I meningiomas and assessed the association between extent of resection, as evaluated using the Simpson classification, and recurrence-free survival (RFS) of patients after meningioma surgery.

METHODS

Clinical and radiological information for patients with WHO Grade I meningiomas who had undergone resective surgery over the past 20 years was retrospectively reviewed. Simpson and Shinshu grading scales were used to evaluate the extent of resection. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression.

RESULTS

Four hundred fifty-eight patients were eligible for analysis. Overall tumor recurrence rates for Simpson resection Grades I, II, III, and IV were 5%, 22%, 31%, and 35%, respectively. After Cox regression analysis, Simpson Grade I (extensive resection) was revealed as a significant predictor of RFS (p = 0.003). Patients undergoing Simpson Grade I and II resections showed significant improvement in RFS compared with patients undergoing Grade III and IV resections (p = 0.005). Extent of resection had a significant effect on recurrence rates for both skull base (p = 0.047) and convexity (p = 0.012) meningiomas. Female sex and a Karnofsky Performance Scale score > 70 were also identified as independent predictors of RFS after resection of WHO Grade I meningioma.

CONCLUSIONS

In this patient cohort, a significant association was noted between extent of resection and rates of tumor recurrence. In the authors' experience the Simpson grading system maintains its relevance and prognostic value and can serve an important role for patient education. Even though complete tumor resection is the goal, surgery should be tailored to each patient according to the risks and surgical morbidity.