Karthik Madhavan

Predictors of Long-Term Survival in Patients With Glioblastoma Multiforme: Advancements From the Last Quarter Century

Over the last quarter century there has been significant progress toward identifying certain characteristics and patterns in GBM patients to predict survival times and outcomes. We sought to identify clinical predictors of survival in GBM patients from the past 24 years. We examined patient survival related to tumor locations, surgical treatment, postoperative course, radiotherapy, chemotherapy, patient age, GBM recurrence, imaging characteristics, serum, and molecular markers. We present predictors that may increase, decrease, or play no significant role in determining a GBM patients long-term survival or affect the quality of life.

Managing Intracranial Incidental Findings Suggestive of Low-Grade Glioma: Learning from Experience

NTRODUCTION Learning from experiencemay be one of themost important and pragmatic tools physicians possess today despite the uncertain nature of science. In today’s scientific world, hysicians constantly address the following question: How does ne deal with something he or she has not experienced or did not xpect? Will the physician be prone to failure regardless as Shaw uggests? Although these questions have confounded health care eams for years, they do have certain weight and relevance when onsidering current ethical and practical dilemmas of physicians anaging “unexpected” or incidental lesions. It is likely that very physician will encounter incidental lesions at some point in is or her career. As the overall number of incidental findings ncreases with the increasing frequency of radiographic scans, hese questions will soon begin to hold more importance and ravity. Specifically in the realm of neuroimaging, our experience with he “unexpected” has been insufficient. Today, there has yet to be consensus on the management of incidental findings found on agnetic resonance imaging (MRI), and different authors have eported various methods of managing these lesions (5). Some authors have suggested a uniform policy for handling incidental findings for all neuroimaging research, although research studies may not be the primary mode of discovery (1). Although most incidental findings on brain MRI are nonurgent (requiring no referral), approximately 1%–2% of these findings require routine or urgent referral to specialists (4). Of the referred patients, patients who present with MRI findings suggestive of low-grade gliomas (LGG) are even rarer with a reported incidence of 0.05% of the healthy population (6). Suspected incidental low-grade

Mini-Open Pedicle Subtraction Osteotomy: Surgical Technique

OBJECTIVE Minimally invasive spinal surgery (MISS) has many favorable attributes that would be of great benefit to patients with an adult spinal deformity. Decreased blood loss, lower infection rates, and faster mobilization may help to reduce the high rate of complications associated with these interventions. Although correction of coronal deformity has been well demonstrated with MISS, improvements in lordosis and sagittal balance have remained relatively elusive using the MISS approach. With open surgery, the most powerful techniques for improving sagittal balance include some form of a spinal osteotomy. METHODS In this report, we describe the evolution of a technique for treating thoracolumbar kyphoscoliosis using a mini-open pedicle subtraction osteotomy (PSO) combined with interbody fusion and percutaneous pedicle screws. RESULTS The patient underwent a T10 to S1 percutaneous posterior instrumented with an L3 PSO and right L4/5 minimally invasive transforaminal interbody fusion. Clinically, the patient had excellent improvement and regained the ability to ambulate independently for distances of up to one half mile. Imaging demonstrated good correction of coronal imbalance (1.8 to 9.5 cm) and sagittal imbalance (sagittal vertical axis of 22.5 to 7 cm). CONCLUSIONS The correction of sagittal plane deformities remains difficult using MISS approaches. In this report, we describe a new technique using a mini-open PSO technique to achieve significant improvement in thoracolumbar lordosis.

The management of incidental low-grade gliomas using magnetic resonance imaging: systematic review and optimal treatment paradigm

OBJECT The discovery of incidental low-grade gliomas (LGGs) on MR imaging is rare, and currently there is no existing protocol for management of these lesions. Various studies have approached the dilemma of managing patients with incidental LGGs. While some advocate surgery and radiotherapy, others reserve surgery until there is radiological evidence of growth. For neurosurgeons and radiologists, determining the course of action after routine brain imaging poses not only a medical but also an ethical dilemma. The authors conducted a systematic review of case reports and case series in hopes of enhancing the current understanding of the management options for these rare lesions. METHODS A PubMed search was performed to include all relevant MR imaging studies in which management of suspected incidental LGG was reported. Comparisons were made between the surgical treatment arm and the active surveillance arm in terms of outcome, mode of discovery, reasons for treatment, and histology. RESULTS Nine studies with 72 patients were included in this study (56 in the surgical arm and 16 in the active surveillance arm). Within the surgical arm, 49% remained deficit free after treatment, 25% showed evidence of tumor progression, 13% underwent a second treatment, and 7% died. The active surveillance group resulted in no unanticipated adverse events, with serial imaging revealing no tumor growth in all cases. Lesion regression was reported in 31% of this group. The surgical arms mortality rate was 7% compared with 0% in the active surveillance arm. CONCLUSIONS Treatment decisions for incidental LGG should be individualized based on presenting symptoms and radiological evidence of growth. The asymptomatic patient may be monitored safely with serial MR imaging and occasionally PET scanning before treatment is initiated. In patients presenting with nonspecific symptoms or concurrent symptomatic lesions, treatment may be initiated earlier to reduce potential morbidity. All treatment decisions must be tempered by patient factors and expectations of anticipated benefit.

Anterior Thigh Compartment Syndrome and Local Myonecrosis After Posterior Spine Surgery on a Jackson Table

BACKGROUND Acute compartment syndrome (ACS) after posterior spinal surgery is very uncommon. Most of the reported cases have ACS in the legs related to positioning in the knee-chest position; postoperative ACS in the thighs is exceedingly rare, with only one reported case (17). CASE DESCRIPTION This study reports two patients who had local muscle necrosis/ACS after spine surgery in the prone position and discusses preventive measures. Both of our complications were probably related to reversing the position of the iliac crest and hip pads on a Jackson operating table, which was done to achieve better lumbar lordosis. CONCLUSIONS Our cases indicate the need for a high index of suspicion of ACS in patients who have persistent unresolved pain and local swelling. Tissue pressure monitoring is an option in suspected cases. Iliac crest and thigh pads should not be reversed during positioning on a Jackson table.

The Use of Modest Systemic Hypothermia After Iatrogenic Spinal Cord Injury During Surgery

Iatrogenic spinal cord injury (SCI) is an uncommon (0%-3%), yet devastating, complication of spine surgery. Recent evidence based on small clinical studies indicates that modest hypothermia is a feasible treatment option for severe SCI. We extended this treatment modality to patients with devastating iatrogenic SCI. We conducted a retrospective case series of five male patients (cervical trauma--1, cervical degenerative--2, thoracic trauma--1, and thoracic scoliosis--1) with an age range of 16-51 years (average age of 46 years) with intraoperative motor-evoked potential/somatosensory-evoked potential loss secondary to catastrophic events during the spinal operation associated with new SCI. Modest hypothermia was instituted immediately postsurgery for 24 hours. Four patients also received methylprednisolone. Preoperative American Spinal Injury Association (ASIA) scores were D (n=3) and E (n=2), while immediate postoperative scores were A (n=1), B (n=1), C (n=2), and D (n=1). Immediate postoperative MRI revealed new cord signal change in three patients. Two patients required subsequent surgery. ASIA scores at last follow-up were C (n=1), D (n=3), and E (n=1) with an improvement of 1-2 grades per patient. Adverse events such as pulmonary embolism, deep venous thrombosis, coagulopathy, or infection were not observed. Hypothermia is a feasible treatment option for patients with iatrogenic SCI. While hypothermia has not been proven to improve outcomes in these situations, aggressive medical management, including cooling, resulted in better-than-expected outcomes in this small cohort.

Prophylactic vertebral cement augmentation at the uppermost instrumented vertebra and rostral adjacent vertebra for the prevention of proximal junctional kyphosis and failure following long-segment fusion for adult spinal deformity

BACKGROUND CONTEXT Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common problems after long-segment (>5 levels) thoracolumbar instrumented fusions in the treatment of adult spinal deformity (ASD). No specific surgical strategy has definitively been shown to lower the risk of PJK as the result of a multifactorial etiology. PURPOSE The study aimed to assess the incidence of PJK and PJF in patients treated with prophylactic polymethylmethacrylate (PMMA) cement augmentation at the uppermost instrumented vertebrae (UIV) and rostral adjacent vertebrae (UIV+1). STUDY DESIGN/SETTING This is a retrospective cohort-matched surgical case series at an academic institutional setting. PATIENT SAMPLE Eighty-five adult patients over a 16-year enrollment period were identified with long-segment (>5 levels) posterior thoracolumbar instrumented fusions for ASD. OUTCOME MEASURES Primary outcomes measures were PJK magnitude and PJF formation. Secondary outcomes measures were spinopelvic parameters, as well as global and regional sagittal alignment. METHODS The impact of adjunctive PMMA use in long-segment (≥5 levels) fusion for ASD was assessed in adult patients aged 18 and older. Patients were included with at least one of the following: lumbar scoliosis >20°, pelvic tilt >25°, sagittal vertical axis >5 cm, central sacral vertical line >2 cm, and thoracic kyphosis >60°. The frequency of PJF and the magnitude of PJK were measured radiographically preoperatively, postoperatively, and at maximum follow-up in controls (Group A) and PMMA at the UIV and UIV+1 (Group B). RESULTS Eighty-five patients (64±11.1 years) with ASD were identified: 47 control patients (58±10.6) and 38 patients (71±6.8) treated with PMMA at the UIV and UIV+1. The mean follow-up was 27.9 and 24.2 months in Groups A and B, respectively (p=.10). Preoperative radiographic parameters were not significantly different, except the pelvic tilt which was greater in Group A (26.6° vs. 31.4°, p=.03). Postoperatively, the lumbopelvic mismatch was greater in Group B (14.6° vs. 7.9°, p=.037), whereas the magnitude of PJK was greater in controls (9.36° vs. 5.65°, p=.023). The incidence of PJK was 36% (n=17) and 23.7% (n=9) in Groups A and B, respectively (p=.020). The odds ratio of PJK with vertebroplasty was 0.548 (95% confidence interval=0.211 to 1.424). Proximal junctional kyphosis was observed in 6 (12.8%) controls only (p=.031). The UIV+1 angle, a measure of PJK, was significantly greater in controls (10.0° vs. 6.8°, p=.02). No difference in blood loss was observed. No complications were attributed to PMMA use. CONCLUSIONS The use of prophylactic vertebral cement augmentation at the UIV and rostral adjacent vertebral segment at the time of deformity correction appears to be preventative in the development of proximal junctional kyphosis and failure.

Transforaminal endoscopic discectomy to relieve sciatica and delay fusion in a 31-year-old man with pars defects and low-grade spondylolisthesis

Isthmic spondylolisthesis due to pars defects resulting from trauma or spondylolysis is not uncommon. Symptomatic patients with such pars defects are traditionally treated with a variety of fusion surgeries. The authors present a unique case in which such a patient was successfully treated with endoscopic discectomy without iatrogenic destabilization. A 31-year-old man presented with a history of left radicular leg pain along the distribution of the sciatic nerve. He had a disc herniation at L5/S1 and bilateral pars defects with a Grade I spondylolisthesis. Dynamic radiographic studies did not show significant movement of L-5 over S-1. The patient did not desire to have a fusion. After induction of local anesthesia, the patient underwent an awake transforaminal endoscopic discectomy via the extraforaminal approach, with decompression of the L-5 and S-1 nerve roots. His preoperative pain resolved immediately, and he was discharged home the same day. His preoperative Oswestry Disability Index score was 74, and postoperatively it was noted to be 8. At 2-year follow-up he continued to be symptom free, and no radiographic progression of the listhesis was noted. In this case preservation of stabilizing structures, including the supraspinous and interspinous ligaments and the facet capsule, may have reduced the likelihood of iatrogenic instability while at the same time achieving symptom control. This may be a reasonable option for select patient symptoms confined to lumbosacral radiculopathy.

A review of stereotactic radiosurgery practice in the management of skull base meningiomas

Gross total resection of skull base meningiomas poses a surgical challenge due to their proximity to neurovascular structures. Once the gold standard therapy for skull base meningiomas, microsurgery has been gradually replaced by or used in combination with stereotactic radiosurgery (SRS). This review surveys the safety and efficacy of SRS in the treatment of cranial base meningiomas including 36 articles from 1991 to 2010. SRS produces excellent tumor control with low morbidity rates compared with surgery alone for asymptomatic small skull base meningiomas, patients with risk factors precluding conventional surgery, and as adjuvant therapy for recurrent or residual lesions.

Minimally-Invasive versus Conventional Repair of Spondylolysis in Athletes: A Review of Outcomes and Return to Play

Spondylolysis from pars fracture is a common injury among young athletes, which can limit activity and cause chronic back pain. While current literature has examined the relative benefits of surgical and conservative management of these injuries, no study has yet compared outcomes between conventional direct repair of pars defects and modern minimally invasive procedures. The goals of surgery are pain resolution, return to play at previous levels of activity, and a shorter course of recovery. In this review, the authors have attempted to quantify any differences in outcome between patients treated with conventional or minimally invasive techniques. A literature search was performed of the PubMed database for relevant articles, excluding articles describing conservative management, traumatic injury, or high-grade spondylolisthesis. Articles included for review involved young athletes treated for symptomatic spondylolysis with either conventional or minimally invasive surgery. Two independent reviewers conducted the literature search and judged articles for inclusion. All studies were classified according to the North American Spine Society standards. Of the 116 results of our initial search, 16 articles were included with a total of 150 patients. Due to a paucity of operative details in older studies and inconsistencies in both clinical methods and reporting among most articles, little quantitative analysis was possible. However, patients in the minimally invasive group did have significantly higher rates of pain resolution (p<0.001). Short recovery times were also noted in this group. Both groups experienced low complication rates, and the majority of patients returned to previous levels of activity. Surgical repair of spondylolysis in young athletes is a safe and practical therapy. Current literature suggests that while conventional repair remains effective, minimally invasive procedures better clinical outcomes. We await further data to conduct a more thorough quantitative analysis of these techniques.