Rishi R. Lall

Development of venous thromboembolism (VTE) in patients undergoing surgery for brain tumors: Results from a single center over a 10 year period

Patients who undergo craniotomy for brain neoplasms have a high risk of developing venous thromboembolism (VTE), including deep vein thromboses (DVT) and pulmonary emboli (PE). The reasons for this correlation are not fully understood. This retrospective, single-center review aimed to determine the risk factors for VTE in patients who underwent neurosurgical resection of brain tumors at Northwestern University from 1999 to 2010. Our cohort included 1148 patients, 158 (13.7%) of whom were diagnosed with DVT and 38 (3.3%) of whom were diagnosed with PE. A variety of clinical factors were studied to determine predictors of VTE, including sex, ethnicity, medical co-morbidities, surgical positioning, length of hospital stay, tumor location, and tumor histology. Use of post-operative anticoagulants and hemorrhagic complications were also investigated. A prior history of VTE was found to be highly predictive of post-operative DVT (odds ratio [OR]=7.6, p=0.01), as was the patients sex (OR=14.2, p<0.001), ethnicity (OR=0.5, p=0.04), post-operative intensive care unit days (OR=0.2, p=0.003), and tumor histology (OR=-0.16, p=0.01). Contrary to reports in the literature, the data collected did not indicate that the administration of post-operative medical prophylaxis for VTE was significant in preventing their formation (OR=-0.14, p=0.76). Hemorrhagic complications were low (2.2%) and resultant neurologic deficit was lower still (0.7%). The study indicates that patients with high-grade primary brain tumors and metastatic lesions should receive aggressive preventative measures in the post-operative period.

Measuring Surgical Outcomes in Cervical Spondylotic Myelopathy Patients Undergoing Anterior Cervical Discectomy and Fusion: Assessment of Minimum Clinically Important Difference

Object The concept of minimum clinically important difference (MCID) has been used to measure the threshold by which the effect of a specific treatment can be considered clinically meaningful. MCID has previously been studied in surgical patients, however few studies have assessed its role in spinal surgery. The goal of this study was to assess the role of MCID in patients undergoing anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM). Methods Data was collected on 30 patients who underwent ACDF for CSM between 2007 and 2012. Preoperative and 1-year postoperative Neck Disability Index (NDI), Visual-Analog Scale (VAS), and Short Form-36 (SF-36) Physical (PCS) and Mental (MCS) Component Summary PRO scores were collected. Five distribution- and anchor-based approaches were used to calculate MCID threshold values average change, change difference, receiver operating characteristic curve (ROC), minimum detectable change (MDC) and standard error of measurement (SEM). The Health Transition Item of the SF-36 (HTI) was used as an external anchor. Results Patients had a significant improvement in all mean physical PRO scores postoperatively (p<0.01) NDI (29.24 to 14.82), VAS (5.06 to 1.72), and PCS (36.98 to 44.22). The five MCID approaches yielded a range of values for each PRO: 2.00–8.78 for PCS, 2.06–5.73 for MCS, 4.83–13.39 for NDI, and 0.36–3.11 for VAS. PCS was the most representative PRO measure, presenting the greatest area under the ROC curve (0.94). MDC values were not affected by the choice of anchor and their threshold of improvement was statistically greater than the chance of error from unimproved patients. Conclusion SF-36 PCS was the most representative PRO measure. MDC appears to be the most appropriate MCID method. When MDC was applied together with HTI anchor, the MCID thresholds were: 13.39 for NDI, 3.11 for VAS, 5.56 for PCS and 5.73 for MCS.

Evidence-based management of deep wound infection after spinal instrumentation

In this study, evidence-based medicine is used to assess optimal surgical and medical management of patients with post-operative deep wound infection following spinal instrumentation. A computerized literature search of the PubMed database was performed. Twenty pertinent studies were identified. Studies were separated into publications addressing instrumentation retention versus removal and publications addressing antibiotic therapy regimen. The findings were classified based on level of evidence (I-III) and findings were summarized into evidentiary tables. No level I or II evidence was identified. With regards to surgical management, five studies support instrumentation retention in the setting of early deep infection. In contrast, for delayed infection, the evidence favors removal of instrumentation at the time of initial debridement. Surgeons should be aware that for deformity patients, even if solid fusion is observed, removal of instrumentation may be associated with significant loss of correction. A course of intravenous antibiotics followed by long-term oral suppressive therapy should be pursued if instrumentation is retained. A shorter treatment course may be appropriate if hardware is removed.

Survival after surgery and stereotactic radiosurgery for patients with multiple intracranial metastases: results of a single-center retrospective study

OBJECTIVES Patients with systemic cancer and a single brain metastasis who undergo treatment with resection plus radiotherapy live longer and have a better quality of life than those treated with radiotherapy alone. Historically, whole-brain radiotherapy (WBRT) has been the mainstay of radiation therapy; however, it is associated with significant delayed neurocognitive sequelae. In this study, the authors looked at survival in patients with single and multiple intracranial metastases who had undergone surgery and adjuvant stereotactic radiosurgery (SRS) to the tumor bed and synchronous lesions. METHODS The authors retrospectively reviewed the records from an 8-year period at a single institution for consecutive patients with brain metastases treated via complete resection of dominant lesions and adjuvant radiosurgery. The cohort was analyzed for time to local progression, synchronous lesion progression, new intracranial lesion development, systemic progression, and overall survival. The Kaplan-Meier method (stratified by age, sex, tumor histology, and number of intracranial lesions prior to surgery) was used to calculate both progression-free and overall survival. A Cox proportional-hazards regression model was also fitted with the number of intracranial lesions as the predictor and survival as the outcome controlling for disease severity, age, sex, and primary histology. RESULTS The median overall follow-up among the 150-person cohort eligible for analysis was 17 months. Patients had an average age of 46.2 years (range 16-82 years), and 62.7% were female. The mean (± standard deviation) number of intracranial lesions per patient was 2.5 ± 2.3. The mean time between surgery and stereotactic radiosurgery (SRS) was 3.2 ± 4.1 weeks. Primary cancers included lung cancer (43.3%), breast cancer (21.3%), melanoma (10.0%), renal cell carcinoma (6.7%), and colon cancer (6.7%). The average number of isocenters per treated lesion was 7.6 ± 6.6, and the average treatment dose was 17.8 ± 2.8 Gy. One-year survival for patients in this cohort was 52%, and the 1-year local control rate was 77%. The median (±standard error) overall survival was 13.2 ± 1.9 months. There was no difference in survival between patients with a single lesion and those with multiple lesions (p = 0.319) after controlling for age, sex, and histology of primary tumor. Patients with primary breast histology had the greatest overall median survival (22.9 ± 6.2 months); patients with colorectal cancer had the shortest overall median survival (5.3 ± 1.8 months). The most common cause of death in this series was systemic progression (79%). CONCLUSIONS These results confirm that 1-year survival for patients with multiple intracranial metastases treated with resection followed by SRS to both the tumor bed and synchronous lesions is similar to established outcomes for patients with a single intracranial metastasis.

Comparison of open and minimally invasive surgery for intradural-extramedullary spine tumors.

OBJECT Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS. METHODS A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups. RESULTS Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81). The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05). CONCLUSIONS Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

Thoracic spinal cord intramedullary aspergillus invasion and abscess

Invasive central nervous system aspergillosis is a rare form of fungal infection that presents most commonly in immunocompromised individuals. There have been multiple previous reports of aspergillus vertebral osteomyelitis and spinal epidural aspergillus abscess; however to our knowledge there are no reports of intramedullary aspergillus infection. We present a 19-year-old woman with active acute lymphoblastic leukemia who presented with several weeks of fevers and bilateral lower extremity weakness. She was found to have an intramedullary aspergillus abscess at T12-L1 resulting from adjacent vertebral osteomyelitis and underwent surgical debridement with ultra-sound guided aspiration and aggressive intravenous voriconazole therapy. To our knowledge this is the first reported case of spinal aspergillosis invading the intramedullary cavity. Though rare, this entity should be included in the differential for immunocompromised patients presenting with fevers and neurologic deficit. Early recognition with aggressive neurosurgical intervention and antifungal therapy may improve outcomes in future cases.

Delayed malignant transformation of petroclival meningioma to chondrosarcoma after stereotactic radiosurgery

Stereotactic radiosurgery (SRS) is often used as adjuvant treatment for residual or recurrent tumor following microsurgical resection of posterior fossa meningiomas. SRS is associated with excellent rates of local control, however long-term complications remain unclear. Secondary malignancy is an often discussed but rarely described complication of SRS. We present a 56-year-old woman who underwent near total resection of a petroclival meningioma, followed by two episodes of SRS over the ensuing 8 years for local recurrence. She returned 14 years after initial diagnosis with neurologic deterioration and was found to have massive recurrence. Pathology was consistent with high-grade chondrosarcoma. The tumor continued to progress despite debulking and proton-beam therapy and the patient died of medical complications. To our knowledge this is the first report of malignant transformation of a meningioma to high-grade chondrosarcoma, further notable due to the remarkable clinical course and delayed presentation after initial surgery and radiosurgery. Though this may have been a de novo tumor, it is also possible that this represents a case of radiation-induced neoplasm. Although SRS continues to gain favor as a treatment modality, delayed malignant degeneration is a potential complication and physicians should counsel patients of this risk.

Low-Dose Gamma Knife Radiosurgery for Vestibular Schwannomas: Tumor Control and Cranial Nerve Function Preservation After 11 Gy

Objectives This study aims to report tumor control rates and cranial nerve function after low dose (11.0 Gy) Gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas. Methods A retrospective chart review was performed on 30 consecutive patients with vestibular schwannomas treated from March 2004 to August 2010 with GKRS at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. The marginal dose for all patients was 11.0 Gy prescribed to the 50% isodose line. Median follow‐up time was 42 months. The median treatment volume was 0.53 cm3. Hearing data were obtained from audiometry reports before and after radiosurgery. Results The actuarial progression free survival (PFS) based on freedom from surgery was 100% at 5 years. PFS based on freedom from persistent growth was 91% at 5 years. One patient experienced tumor progression requiring resection at 87 months. Serviceable hearing, defined as Gardner‐Robertson score of I‐II, was preserved in 50% of patients. On univariate and multivariate analyses, only higher mean and maximum dose to the cochlea significantly decreased the proportion of patients with serviceable hearing. Conclusion Vestibular schwannomas can be treated with low doses (11.0 Gy) of GKRS with good tumor control and cranial nerve preservation.

Spontaneous Thrombosis and Subsequent Recanalization of a Developmental Venous Anomaly

Developmental venous anomalies (DVA) are among the most common congenital malformations of the cerebral angioarchitecture. Spontaneous thrombosis of this entity is rare, and our review of the literature found only 31 reported cases of symptomatic spontaneous thrombosis of developmental venous anomalies. Here, we report a unique case describing the spontaneous thrombosis of a DVA leading to venous infarction and subsequent recanalization. The patient was a previously healthy 21-year-old male who presented with an acute onset of partial seizures. Following negative hypercoagulability studies and along with CT (computed tomography) and MR (magnetic resonance) imaging, the patient was treated with anticoagulant therapy and demonstrated complete functional recovery. Knowledge from our literature review of similar cases combined with the experience gained from this patient’s treatment leads us to suggest that spontaneous DVA thrombosis and venous infarction generally has a good outcome despite initially devastating neurologic deficits. Additionally, the rarity of spontaneous DVA thromboses lends itself to the need to identify possible predisposing risk factors, chief amongst these being hypercoagulopathies.

Survival after surgery and stereotactic radiosurgery for patients with multiple intracranial metastases: results of a single-center retrospective study: Clinical article

OBJECTIVES Patients with systemic cancer and a single brain metastasis who undergo treatment with resection plus radiotherapy live longer and have a better quality of life than those treated with radiotherapy alone. Historically, whole-brain radiotherapy (WBRT) has been the mainstay of radiation therapy; however, it is associated with significant delayed neurocognitive sequelae. In this study, the authors looked at survival in patients with single and multiple intracranial metastases who had undergone surgery and adjuvant stereotactic radiosurgery (SRS) to the tumor bed and synchronous lesions. METHODS The authors retrospectively reviewed the records from an 8-year period at a single institution for consecutive patients with brain metastases treated via complete resection of dominant lesions and adjuvant radiosurgery. The cohort was analyzed for time to local progression, synchronous lesion progression, new intracranial lesion development, systemic progression, and overall survival. The Kaplan-Meier method (stratified by age, sex, tumor histology, and number of intracranial lesions prior to surgery) was used to calculate both progression-free and overall survival. A Cox proportional-hazards regression model was also fitted with the number of intracranial lesions as the predictor and survival as the outcome controlling for disease severity, age, sex, and primary histology. RESULTS The median overall follow-up among the 150-person cohort eligible for analysis was 17 months. Patients had an average age of 46.2 years (range 16-82 years), and 62.7% were female. The mean (± standard deviation) number of intracranial lesions per patient was 2.5 ± 2.3. The mean time between surgery and stereotactic radiosurgery (SRS) was 3.2 ± 4.1 weeks. Primary cancers included lung cancer (43.3%), breast cancer (21.3%), melanoma (10.0%), renal cell carcinoma (6.7%), and colon cancer (6.7%). The average number of isocenters per treated lesion was 7.6 ± 6.6, and the average treatment dose was 17.8 ± 2.8 Gy. One-year survival for patients in this cohort was 52%, and the 1-year local control rate was 77%. The median (±standard error) overall survival was 13.2 ± 1.9 months. There was no difference in survival between patients with a single lesion and those with multiple lesions (p = 0.319) after controlling for age, sex, and histology of primary tumor. Patients with primary breast histology had the greatest overall median survival (22.9 ± 6.2 months); patients with colorectal cancer had the shortest overall median survival (5.3 ± 1.8 months). The most common cause of death in this series was systemic progression (79%). CONCLUSIONS These results confirm that 1-year survival for patients with multiple intracranial metastases treated with resection followed by SRS to both the tumor bed and synchronous lesions is similar to established outcomes for patients with a single intracranial metastasis.