Papers by Ajit Krishnaney
ASA Newsletter, Nov 1, 2019
Journal of NeuroInterventional Surgery, Jul 1, 2010
Objective and importance Cobb syndrome is a rare condition that includes a cutaneous nevus with a... more Objective and importance Cobb syndrome is a rare condition that includes a cutaneous nevus with an associated spinal vascular lesion at the same dermatome. We present a challenging case of a progressively symptomatic massive lumbosacral arteriovenous malformations (AVM) in a patient with Cobb's syndrome requiring a multimodality approach, including staged preoperative transarterial and transvenous endovascular embolization followed by surgical excision and wound reconstruction. Clinical presentation The patient is a 25-year-old man with a massive lumbosacral AVM with symptoms of congestive heart failure. Angiography demonstrated arterial feeders predominantly from the internal iliac, median sacral and lumbar segmental arteries. Intervention The patient underwent staged transarterial and transvenous endovascular embolization resulting in 90% reduction in the AVM size, followed by surgical resection of the lesion. The patient made an excellent recovery with improvement in his symptoms of congestive heart failure. Conclusion The treatment algorithm for massive AVMs must be individualized. A combination of staged embolization and subsequent surgery may be required to obtain a good result. Through this carefully planned multidisciplinary approach, a previously incurable lesion in this patient with Cobb syndrome was able to be treated successfully.Abstract E-041 Figure 1
Neurosurgical Focus, May 1, 2021
M etastatic epidural spinal cord compression (MESCC) is estimated to affect 5%-10% of all patient... more M etastatic epidural spinal cord compression (MESCC) is estimated to affect 5%-10% of all patients with cancer. 1-3 If left untreated, MESCC causes severe pain, progressive neurological impairment, and eventual paraplegia with a median survival of 3-6 months. 3,4 Given the debilitating nature of its complications, MESCC represents a medical emergency that requires urgent intervention. Treatment paradigms for MESCC have rapidly shifted over the past several decades, from isolated radiotherapy or maximal resection toward a combined approach consisting of surgery followed by adjuvant radiation therapy. 5 This approach has been recognized as the standard of care for MESCC since 2005, following work by Patchell et al. that demonstrated greater survival and superior rates of ambulation in patients receiving surgery followed by ra
Clinical spine surgery, Nov 1, 2017
The Spine Journal, Aug 1, 2015
There is currently no consensus on appropriate perioperative management of patients with spinal c... more There is currently no consensus on appropriate perioperative management of patients with spinal cord stimulator implants. Magnetic resonance imaging (MRI) is considered safe under strict labeling conditions. Electrocautery is generally not recommended in these patients but sometimes used despite known risks. The aim was to discuss the perioperative evaluation and management of patients with spinal cord stimulator implants. A literature review, summary of device labeling, and editorial were performed, regarding the safety of spinal cord stimulator devices in the perioperative setting. A literature review was performed, and the labeling of each Food and Drug Administration (FDA)-approved spinal cord stimulation system was reviewed. The literature review was performed using PubMed and the FDA website (www.fda.gov). Magnetic resonance imaging safety recommendations vary between the models. Certain systems allow for MRI of the brain to be performed, and only one system allows for MRI of the body to be performed, both under strict labeling conditions. Before an MRI is performed, it is imperative to ascertain that the system is intact, without any lead breaks or low impedances, as these can result in heating of the spinal cord stimulation (SCS) and injury to the patient. Monopolar electrocautery is generally not recommended for patients with SCS; however, in some circumstances, it is used when deemed required by the surgeon. When cautery is necessary, bipolar electrocautery is recommended. Modern electrocautery units are to be used with caution as there remains a risk of thermal injury to the tissue in contact with the SCS. As with MRI, electrocautery usage in patients with SCS systems with suspected breaks or abnormal impedances is unsafe and may cause injury to the patient. Spinal cord stimulation is increasingly used in patients with pain of spinal origin, particularly to manage postlaminectomy syndrome. Knowledge of the safety concerns of SCS and appropriate perioperative evaluation and management of the SCS system can reduce risks and improve surgical planning.
Neuro-oncology, Nov 1, 2020
NEURO-ONCOLOGY • NOVEMBER 2020 on dosing regimens of 7.5 mg/kg (n=72) or 5 mg/kg per infusion (n=... more NEURO-ONCOLOGY • NOVEMBER 2020 on dosing regimens of 7.5 mg/kg (n=72) or 5 mg/kg per infusion (n=16) (n=88, 14.7% of cohort) developed ICH. Therapeutic anticoagulation and concomitant BEV therapy was observed in 103 (17%) patients with 10 patients (10/93, 9.7%) developing an ICH (n=10), at a rate significantly higher than in patients treated with bevacizumab alone (13/479, 2.6%) (p=0.0025). When hemorrhages occurred (with or without concomitant anticoagulation) they were associated with high morbidity and mortality (ECOG 3.54 versus 1.26, p = < 0.0001), with 12 patients (52%) suffering severe debility (n=2) or death (n=10). CONCLUSION: Bevacizumab associated intracerebral hemorrhages remain uncommon events, similar to the baseline rate of spontaneous hemorrhage associated with malignant glioma. We observed a trend towards significance with higher doses per infusion associated with an increased rate of intracerebral hemorrhage. The combination of anticoagulation and BEV appears to confer a greater risk of hemorrhage than BEV alone.
Surgical Neurology International, Dec 29, 2020
is is an open-access article distributed under the terms of the Creative Commons Attribution-Non... more is is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Journal of Neurosurgical Anesthesiology, Jun 19, 2020
Adequate analgesia is known to improve outcomes after spine surgery. Despite recent attention hig... more Adequate analgesia is known to improve outcomes after spine surgery. Despite recent attention highlighting the negative effects of narcotics and their addiction potential, opioids have been the mainstay of management for providing analgesia following spine surgeries. However, side effects including hyperalgesia, tolerance, and subsequent dependence restrict the generous usage of opioids. Multimodal analgesia regimens acting through different mechanisms offer significant opioid sparing and minimize the side effects of individual drugs. Hence, they are being increasingly incorporated into enhanced recovery protocols. Multimodal analgesia includes drugs such as N-methyl-D-aspartate antagonists, nonsteroidal anti-inflammatory drugs and membrane-stabilizing agents, neuraxial opioids, local anesthetic infiltration, and fascial compartment blocks. Analgesia started before the painful stimulus, termed preemptive analgesia, facilitates subsequent pain management. Both nonsteroidal anti-inflammatory drugs and neuraxial analgesia have been conclusively shown to reduce opioid requirements after spine surgery, and there is a resurgence of interest in the use of low-dose ketamine or methadone. Neuraxial narcotics offer enhanced analgesia for a longer duration with lower dosage and side effect profiles compared with systemic opioid administration. Fascial compartment blocks are increasingly used as they provide effective analgesia with fewer adverse effects. In this narrative review, we will discuss multimodality analgesic regimens incorporating opioid-sparing adjuvants to manage pain after spine surgery.
JAMA Surgery, Oct 1, 2016
Investigations have demonstrated the efficacy of infection prevention bundles in reducing SSIs ac... more Investigations have demonstrated the efficacy of infection prevention bundles in reducing SSIs across multiple surgical specialties. 3,4 Neurosurgical SSIs incur the highest costs, and spine surgeries account for more than 1.01 million procedures annually, presenting an opportunity for reducing health care-related harm and expenditures. 5 We hypothesized that implementation of an infection prevention bundle would be associated with a reduction in SSIs and disease-specific costs.
Neurosurgery, Dec 1, 2020
Journal of neurosurgery, Apr 1, 2020
OBJECTIVEThere are limited data on spine stereotactic radiosurgery (SRS) in treating adolescent a... more OBJECTIVEThere are limited data on spine stereotactic radiosurgery (SRS) in treating adolescent and young adult (AYA) patients. SRS has the advantages of highly conformal radiation dose delivery in the upfront and retreatment settings, means for dose intensification, and administration over a limited number of sessions leading to a decreased treatment burden. In this study, the authors report the oncological and toxicity outcomes for AYA patients with metastatic sarcoma treated with spine radiosurgery and provide clinicians a guide for considerations in dose, volume, and fractionation.METHODSAn institutional review board–approved database of patients treated with SRS in the period from October 2014 through December 2018 was queried. AYA patients, defined by ages 15–29 years, who had been treated with SRS for spine metastases from Ewing sarcoma or osteosarcoma were included in this analysis. Patients with follow-ups shorter than 6 months after SRS were excluded. Local control, overall survival, and toxicity were reported.RESULTSSeven patients with a total of 11 treated lesions were included in this study. Median patient age was 20.3 years (range 15.1–26.1 years). Three patients had Ewing sarcoma (6 lesions) and 4 patients had osteosarcoma (5 lesions). The median dose delivered was 35 Gy in 5 fractions (range 16–40 Gy, 1–5 fractions). The median follow-up was 11.1 months (range 6.8–26.0 months). Three local failures were observed within the follow-up period. No acute grade 3 or greater toxicity was observed. One patient developed late grade 3 toxicity consisting of radiation enteritis. This patient had previously received radiation to an overlapping volume with conventional fractionation. SRS re-irradiation for this patient was also performed concurrently with chemotherapy administration. No late grade 4 or higher toxicities were observed. No pain flare or vertebral compression fracture was observed. Three patients died within the follow-up period.CONCLUSIONSSRS for spine metastases from Ewing sarcoma and osteosarcoma can be considered as a treatment option in AYA patients and is associated with acceptable toxicity rates. Further studies must be conducted to determine long-term local control and toxicity for this treatment modality.
Neurosurgery, Jun 1, 2007
World Neurosurgery, Feb 1, 2018
Background We report a series of three cases of metastatic thy moma to the spine with spinal cord... more Background We report a series of three cases of metastatic thy moma to the spine with spinal cord compression. An extensive literature review of thym ic etastases to the spine was completed in order to provide a comprehensive appra isal of current prognostic indicators and potential treatment algorithms to help guide cl inicians in treatment management. Case Descriptions Between 2000 and 2017, three patients were diagnose d with thymic metastases to the spine at our institution. Metastasis presentation o ccurred from two to eight years following initial diagnosis with thymic cancer. All three patients presented with signs and symptoms of spinal cord/cauda equina compression, a nd underwent surgical intervention. Post-operative treatments varied amongst all three: on receiving chemotherapy, another undergoing radiation, and the third having had no f urther treatment due to extensive systemic disease. Conclusions Upon review of the literature, 16 case reports/seri e described 28 total patients with spine metastases secondary to thymoma/thymic carcinoma. P resentation varied widely, including age, neurological deficits, time from ini t al diagnosis to metastasis, and histological grading. The only widely accepted prog n stic factor is completeness of tumor resection, while clinical staging and/or hist ological type may also have prognostic value. Thus, gross total resection and spinal decom pression should be prioritized in cases of surgical intervention. Chemotherapy and radiothe rapy are generally recommended. However, given the lack of standardized treatment a lgorithms, individualized regimens should be formulated on a case-specific basis. M AN US CR IP T AC CE PT ED ACCEPTED MANUSCRIPT Introduction The spine is the most common site for bony metastas is, with cancers from the lungs, breast, and prostate as the predominant etiologies. 16–18 Approximately 5-10 % of all cancer patients will have one or more spinal metast a ic lesion during the course of their disease. A thorough understanding of the behavior of and treatment options for even rare tumors is necessary. 19 Thymoma is a rare anterior mediastinal tumor that o riginates in the epithelial cells of the thymus, with an overall incidence of approximately 3.2 per million annually. Thymomas may be discovered incidentally in asymptomatic pati ents on a chest radiograph or computed tomography (CT), or patients may present w ith symptomatic mass effect, complaining of dysphagia, cough, and/or chest pain. 21 Additionally, approximately 45% of patients with thymoma are diagnosed with myasthe nia gravis. 22 Thymomas are characterized by the World Health Organization (WHO ) histological grading and Masaoka-Koga clinical staging. 23,24 WHO histological grading assigns thymomas a letter (A, B or AB) dependent on the shape of the neoplast ic epithelial cells. Type B thymomas are assigned numbers (ie B1, B2, B3) based on incre asing emergence of atypia and increasing proportion of neoplastic epithelial cell s to lymphocytes. 25 Thymomas, whose cytoarchitectural features no longer resemble thymi c tissue and are, instead, akin to carcinomas from other organs, are classified as typ e C thymomas (often referred to as thymic carcinoma). 25 In contrast, the Masaoka-Koga grading system chara terizes thymomas based on the extent of invasion, with stag e IVb denoting hematogenous and/or lymphatic dissemination. Thymomas with extrathoraci c metastases (stage IVb) are uncommon, occurring in roughly 15% of patients with thymoma. 11 The most frequent locations include the liver, kidney, and bone. 11 However, it is very rare for these tumors to metastasize to the spine. 20 Surgical resection is the mainstay of treatment for hymic tumors. Prognosis is predicted based on the extent of resection and Masaoka-Koga c linical staging, with early staged tumors (Masaoka-Koga I and II) demonstrating 10-yea r overall survival (OS) rates of 80 to 90%. Thymomas are generally radiosensitive and chemosen sitive tumors, with M AN US CR IP T AC CE PT ED ACCEPTED MANUSCRIPT response rates ranging from 62 to 100%. 21,27,28 Thus, higher staged tumors (MasaokaKoga III and IV) often involve surgery with adjuvan t chemoradiotherapy, although such adjuvant therapy is not standardized. 21,27,28 In general, late stage thymoma has five-year OS rates from 39 to 72% in population studies. 20 However, little is known about the natural history f metastatic thymoma to the spine. Currently, no treatment guidelines exist due to the variability in treatment modalities and reported outcomes as well as a lack of thorough cas e series and literature review. Here, the authors present three rare cases of metastatic thymoma to the thoracolumbar spine, in addition to discussion of all known and reported ca ses of such spinal metastases compiled through extensive literature review, with the goal f helping to establish and standardize treatment guidelines through future studies.
Neurosurgery Quarterly, Dec 1, 2004
Penetrating spinal injuries, although not as common as blunt trauma, are important causes of spin... more Penetrating spinal injuries, although not as common as blunt trauma, are important causes of spinal cord injury. Two types of penetrating injuries exist, gunshot wounds and stab wounds. Surgery does not play a significant role in gunshot wounds unless there is incomplete myelopathy with a surgically correctable cause, such as hematoma. Stab wounds have a better prognosis. Moreover, surgery plays a much larger role. Retained foreign objects should be removed after a stab injury, whereas bullet fragments should be left in place.
Neurology India, 2005
Although anterior cervical instrumentation was initially used in cervical trauma, because of obvi... more Although anterior cervical instrumentation was initially used in cervical trauma, because of obvious benefits, indications for its use have been expanded over time to degenerative cases as well as tumor and infection of the cervical spine. Along with a threefold increase in incidence of cervical fusion surgery, implant designs have evolved over the last three decades. Observation of graft subsidence and phenomenon of stress shielding led to the development of the new generation dynamic anterior cervical plating systems. Anterior cervical plating does not conclusively improve clinical outcome of the patients, but certainly enhances the efficacy of autograft and allograft fusion and lessens the rate of pseudoarthrosis and kyphosis after multilevel discectomy and fusions. A review of biomechanics, surgical technique, indications, complications and results of various anterior cervical plating systems is presented here to enable clinicians to select the appropriate construct design.
Neurosurgery Clinics of North America, Oct 1, 2004
World Neurosurgery, Aug 1, 2017
Background: Central sensitization (CS) is an abnormal and intense enhancement of pain mechanism b... more Background: Central sensitization (CS) is an abnormal and intense enhancement of pain mechanism by the central nervous system. Patients with CS may be at higher risk of poor outcomes following spinal fusion. The Central Sensitivity Inventory or Index (CSI) was developed to identify and quantify key symptoms related to CS. Methods: Evaluate retrospectively pretreatment CSI as a predictor of post-operative quality of life (QOL) measures, length of stay (LOS), and discharge status in patients who underwent thoracic and/or lumbar fusion. Results: 664 patients were included. Pre-operative PDQ scores, PHQ-9 scores, and EQ-5D index scores were significantly worse in patients with a pre-operative CSI score ≥ 40 compared to patients with a pre-operative CSI < 40 (P <0.0001 for all). After adjusting for demographic variables, operation duration, and pre-operative health status, pre-operative CSI score was significantly associated with higher post-operative PDQ total score
Spine, Feb 1, 2011
This is a prospective in vivo study comparing radiation exposure to the surgeon during 10 minimal... more This is a prospective in vivo study comparing radiation exposure to the surgeon during 10 minimally invasive lumbar microdiscectomy cases with 10 traditional open discectomy cases as a control. Radiation exposure to the eye, chest, and hand of the operating surgeon during minimally invasive surgery (MIS) and open lumbar microdiscectomy were measured. The Occupational Exposure Guidelines were used to calculate the allowable number of cases per year from the mean values at each of the 3 sites. Fluoroscopy is a source of ionizing radiation and as such, is a potential health hazard with continued exposure during surgery. Presently, radiation exposure to the surgeon during MIS lumbar microdiscectomy is unknown. Radiation exposure to the surgeon (millirads [mR]) per case was measured by digital dosimeters placed at the level of the thyroid/eye, chest, and dominant forearm. Other data collected included operative side and level, side of the surgeon, side of the x-ray source, total fluoroscopy time, and energy output. The average radiation exposure to the surgeon during open cases was thyroid/eye 0.16 ± 0.22 mR, chest 0.21 ± 0.23 mR, and hand 0.20 ± 0.14 mR. During minimally invasive cases exposure to the thyroid/eye was 1.72 ± 1.52 mR, the chest was 3.08 ± 2.93 mR, and the hand was 4.45 ± 3.75 mR. The difference between thyroid/ eye, chest, and hand exposure during open and minimally invasive cases was statistically significant (P = 0.010, P = 0.013, and P = 0.006, respectively). Surgeons standing in an adjacent substerile room during open cases were exposed to 0.2 mR per case. MIS lumbar microdiscectomy cases expose the surgeon to significantly more radiation than open microdiscectomy. One would need to perform 1623 MIS microdiscectomies to exceed the exposure limit for whole-body radiation, 8720 cases for the lens of the eye, and 11,235 cases for the hand. Standing in a substerile room during x-ray localization in open cases is not fully protective.
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Papers by Ajit Krishnaney