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Nathan T. Zwagerman, Eric W. Wang, Samuel S. Shin, Yue-Fang Chang, Juan C. Fernandez-Miranda, Carl H. Snyderman, and Paul A. Gardner

OBJECTIVE

Based on a null hypothesis that the use of short-term lumbar drainage (LD) after endoscopic endonasal surgery (EES) for intradural pathology does not prevent postoperative CSF leaks, a trial was conducted to assess the effect of postoperative LD on postoperative CSF leak following standard reconstruction.

METHODS

A prospective, randomized controlled trial of lumbar drain placement after endoscopic endonasal skull base surgery was performed from February 2011 to March 2015. All patients had 3-month follow-up data. Surgeons were blinded to which patients would or would not receive the drain until after closure was completed. An a priori power analysis calculation assuming 80% of power, 5% postoperative CSF leak rate in the no-LD group, and 16% in the LD group determined a planned sample size of 186 patients. A routine data and safety check was performed with every 50 patients being recruited to ensure the efficacy of randomization and safety. These interim tests were run by a statistician who was not blinded to the arms they were evaluating. This study accrued 230 consecutive adult patients with skull base pathology who were eligible for endoscopic endonasal resection. Inclusion criteria (high-flow leak) were dural defect greater than 1 cm2 (mandatory), extensive arachnoid dissection, and/or dissection into a ventricle or cistern. Sixty patients were excluded because they did not meet the inclusion criteria. One hundred seventy patients were randomized to either receive or not receive a lumbar drain.

RESULTS

One hundred seventy patients were randomized, with a mean age of 51.6 years (range 19–86 years) and 38% were male. The mean BMI for the entire cohort was 28.1 kg/m2. The experimental cohort with postoperative LD had an 8.2% rate of CSF leak compared to a 21.2% rate in the control group (odds ratio 3.0, 95% confidence interval 1.2–7.6, p = 0.017). In 106 patients in whom defect size was measured intraoperatively, a larger defect was associated with postoperative CSF leak (6.2 vs 2.9 cm2, p = 0.03). No significant difference was identified in BMI between those with (mean 28.4 ± 4.3 kg/m2) and without (mean 28.1 ± 5.6 kg/m2) postoperative CSF leak (p = 0.79). Furthermore, when patients were grouped based on BMI < 25, 25–29.9, and > 30 kg/m2, no difference was noted in the rates of CSF fistula (p = 0.97).

CONCLUSIONS

Among patients undergoing intradural EES judged to be at high risk for CSF leak as defined by the study’s inclusion criteria, perioperative LD used in the context of vascularized nasoseptal flap closure significantly reduced the rate of postoperative CSF leaks.

Clinical trial registration no.: NCT03163134 (clinicaltrials.gov).

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Eric W. Franz, J. Nicole Bentley, Patricia P. S. Yee, Kate W. C. Chang, Jennifer Kendall-Thomas, Paul Park, and Lynda J. S. Yang

OBJECT

Patient outcome measures are becoming increasingly important in the evaluation of health care quality and physician performance. Of the many novel measures currently being explored, patient satisfaction and other subjective measures of patient experience are among the most heavily weighted. However, these subjective measures are strongly influenced by a number of factors, including patient demographics, level of understanding of the disorder and its treatment, and patient expectations. In the present study, patients referred to a neurosurgery clinic for degenerative spinal disorders were surveyed to determine their understanding of lumbar spondylosis diagnosis and treatment.

METHODS

A multiple-choice, 6-question survey was distributed to all patients referred to a general neurosurgical spine clinic at a tertiary care center over a period of 11 months as a quality improvement initiative to assist the provider with individualized patient counseling. The survey consisted of questions designed to assess patient understanding of the role of radiological imaging in the diagnosis and treatment of low-back and leg pain, and patient perception of the indications for surgical compared with conservative management. Demographic data were also collected.

RESULTS

A total of 121 surveys were included in the analysis. More than 50% of the patients indicated that they would undergo spine surgery based on abnormalities found on MRI, even without symptoms; more than 40% of patients indicated the same for plain radiographs. Similarly, a large proportion of patients (33%) believed that back surgery was more effective than physical therapy in the treatment of back pain without leg pain. Nearly one-fifth of the survey group (17%) also believed that back injections were riskier than back surgery. There were no significant differences in survey responses among patients with a previous history of spine surgery compared with those without previous spine surgery.

CONCLUSIONS

These results show that a surprisingly high percentage of patients have misconceptions regarding the diagnosis and treatment of lumbar spondylosis, and that these misconceptions persist in patients with a history of spine surgery. Specifically, patients overemphasize the value of radiological studies and have mixed perceptions of the relative risk and effectiveness of surgical intervention compared with more conservative management. These misconceptions have the potential to alter patient expectations and decrease satisfaction, which could negatively impact patient outcomes and subjective valuations of physician performance. While these results are preliminary, they highlight a need for improved communication and patient education during surgical consultation for lumbar spondylosis.

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Shervin R. Dashti, Humain Baharvahdat, Robert F. Spetzler, Eric Sauvageau, Steven W. Chang, Michael F. Stiefel, Min S. Park, and Nicholas C. Bambakidis

Object

Postoperative infection after cranial surgery is a serious complication that requires immediate recognition and treatment. In certain cases such as postoperative meningitis, the patient can be treated with antibiotics only. In cases that involve a bone flap infection, subdural empyema, or cerebral abscess, however, reoperation is often needed. There has been significant disagreement regarding the incidence of postoperative central nervous system (CNS) infections following cranial surgery. In this paper the authors' goal was to perform a retrospective review of the incidence of CNS infection after cranial surgery at their institution. They focused their review on those patients who required repeated surgery to treat the infection.

Methods

The authors reviewed the medical records and imaging studies in all patients who underwent a craniotomy or stereotactic drainage for CNS infection over the past 10 years. Subgroup analysis was then performed in patients whose infection was a result of a previous cranial operation to determine the incidence, factors associated with infection, and the type of infectious organism. Patients treated nonoperatively (that is, those who received intravenous antibiotics for postoperative meningitis or cellulitis) were not included. Patients treated for wound infection without intracranial pus were also not included.

Results

During the study period from January 1997 through December 2007, ~ 16,540 cranial surgeries were performed by 25 neurosurgeons. These included elective as well as emergency and trauma cases. Of these cases 82 (0.5%) were performed to treat postoperative infection in 50 patients. All 50 patients underwent their original surgery at the authors' institution. The median age was 51 years (range 2–74 years). There were 26 male and 24 female patients.

The most common offending organism was methicillin-sensitive Staphylococcus aureus, which was found in 10 of 50 patients. Gram-negative rods were found in 15 patients. Multiple organisms were identified in specimens obtained in 5 patients. Six patients had negative cultures. Most craniotomies leading to subsequent infection were performed for tumors or other mass lesions (23 of 50 patients), followed by craniotomies for hemorrhage and vascular lesions. Almost half of the patients underwent > 1 cranial operation before presenting with infection.

Conclusions

Postoperative infection after cranial surgery is an important phenomenon that needs immediate recognition. Even with strict adherence to sterile techniques and administration of antibiotic prophylaxis, a small percentage of these patients will develop an infection severe enough to require reoperation.

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Kelly Lamiman, Kenneth K. Wong, Benita Tamrazi, Jason D. Nosrati, Arthur Olch, Eric L. Chang, and Erin N. Kiehna

OBJECTIVE

When complete resection of craniopharyngioma is not achievable or the sequelae are prohibitive, limited surgery and radiation therapy have demonstrated excellent local disease control while minimizing treatment-related sequelae. When residual tissue exists, there is a propensity for further cyst development and expansion during and after radiation therapy. This can result in obstructive hydrocephalus, visual changes, and/or clinical decline. The authors present a quantitative analysis of cyst expansion during and after radiotherapy and examine how it affected subsequent management.

METHODS

The authors performed an institutional review board–approved retrospective study of patients with histologically confirmed craniopharyngioma treated between 2000 and 2015 with surgery and intensity-modulated radiation therapy (IMRT) at a single institution. Volumetric measurements of cyst contours were generated by radiation oncology treatment planning software postoperatively, during IMRT, and up to 12 months after IMRT. Patient, tumor, and treatment–related variables were collected until the last known follow-up and were analyzed.

RESULTS

Twenty-seven patients underwent surgery and IMRT. The median total radiation dose was 54 Gy. Of the 27 patients, 11 patients (40.7%) demonstrated cyst expansions within 1 year of IMRT. Of note, all tumors with cyst expansion were radiographically Puget Grade 2. Maximal cyst expansion peaked at 4.27 months following radiation therapy, with a median volume growth of 4.1 cm3 (mean 9.61 cm3) above the postoperative cyst volume. Eight patients experienced spontaneous cyst regression without therapeutic intervention. Three patients experienced MRI-confirmed cyst enlargement during IMRT, all of whom required adaptive planning to ensure adequate coverage of the entire tumor volume. Two of these 3 patients required ventriculoperitoneal shunt placement and additional intervention. One underwent additional resection, and the other had placement of an intracystic catheter for aspiration and delivery of intracystic interferon within 12 months of completing IMRT. All 3 patients now have stable disease.

CONCLUSIONS

Craniopharyngioma cyst expansion occurred in approximately 40% of the patients during or after radiotherapy. In the majority of patients, cyst expansion was a self-limiting process and did not confer a worse outcome. During radiotherapy, cyst expansion may be apparent on image-guided radiation therapy. Adaptive IMRT planning may be required to ensure that the intended IMRT dose covers the entire tumor and cyst volume. The sequelae of cyst expansion include progressive hydrocephalus, which may be treated with a shunt. For patients with solitary cyst expansion, cyst aspiration and/or intracystic interferon may result in disease control.

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Leopold Arko IV, Eric Quach, Vincent Nguyen, Daniel Chang, Vishad Sukul, and Bong-Soo Kim

Object

Spinal epidural abscess (SEA) is a rare condition that has previously been treated with urgent surgical decompression and antibiotics. Recent availability of MRI makes early diagnosis possible and allows for the nonoperative treatment of SEA in select patients. The first retrospective review of medically and surgically managed SEA was published in 1999, and since that time several other retrospective institutional reports have been published. This study reviews these published reports and compares pooled data with historical treatment data.

Methods

A PubMed keyword and Boolean search using (“spinal epidural abscess” OR “spinal epidural abscesses” AND [management OR treatment]) returned 429 results. Filters for the English language and publications after 1999 were applied, as the first study comparing operative and nonoperative management was published that year. Articles comparing operative to nonoperative treatment strategies for SEA were identified, and the references were further reviewed for additional articles. Studies involving at least 10 adult patients (older than 18 years) were included. Case reports, studies reporting either medical or surgical management only, studies not reporting indications for conservative management, or studies examining SEA as a result of a specific pathogen were excluded.

Results

Twelve articles directly comparing surgical to nonsurgical management of SEA were obtained. These articles reported on a total of 1099 patients. The average age of treated patients was 57.24 years, and 62.5% of treated patients were male. The most common pathogens found in blood and wound cultures were Staphylococcus aureus (63.6%) and Streptococcus species (6.8%). The initial treatment was surgery in 59.7% of cases and medical therapy in 40.3%. This represented a significant increase in the proportion of medically managed patients in comparison with the historical control prior to 1999 (p < 0.05). Patients with no neurological deficits were significantly more likely to be treated medically than surgically (p < 0.05). There was no statistically significant difference overall between surgical and nonsurgical management, although several risk factors may predict failure of medical management.

Conclusions

. Since the first reports of nonoperative treatment of SEA, there has been a substantial trend toward treating neurologically intact patients with medical management. Nevertheless, medical therapy fails in a fair number of cases involving patients with specific risk factors, and patients with these risk factors should be closely observed in consideration for surgery. Further research may help identify patients at greater risk for failure of medical therapy.

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Shervin R. Dashti, Humain Baharvahdat, Eric Sauvageau, Steven W. Chang, Michael F. Stiefel, Min S. Park, Robert F. Spetzler, and Nicholas C. Bambakidis

✓ Brain abscess is a rare but very dangerous neurosurgical lesion. Prompt diagnosis and emergency surgical evacuation are the hallmarks of therapy. Brain abscess following ischemic and hemorrhagic stroke is a rare entity. These cases are often preceded by episodes of bacteremia, sepsis, and local infection. The authors report the case of a 30-year-old woman who presented with a cerebral abscess at the site of a recent intraparenchymal hemorrhage.

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Skeletal dysplasia involving the subaxial cervical spine

Report of two cases and review of the literature

Gregory P. Lekovic, Nitin R. Mariwalla, Eric M. Horn, Steven Chang, Harold L. Rekate, and Nicholas Theodore

✓ Because skeletal dysplasias are primary disorders of bone, they have not been commonly understood as neurosurgical diseases. Nevertheless, neurosurgical complications are commonly encountered in many cases of dysplasia syndromes. The authors present two cases of skeletal dysplasia that caused overt instability of the cervical spine. One patient with a diagnosis of Gorham disease of the cervical spine was treated with prolonged fixation in a halo brace after an initial attempt at instrumentation with a posterior occiput–C4 fusion. The other patient, who at birth was identified to have camptomelic dysplasia, has been treated conservatively from the outset. Although these two patients presented with different disorders—in one patient adequate mature bone never formed and in the other patient progressive bone loss became apparent after a seemingly normal initial development—these cases demonstrate unequivocally that surgical options for fusion are ultimately limited by the quality of the underlying bone. In patients in whom the bone itself is inadequate for use as a substrate for fusion, there are currently limited treatment options. Future improvements in our understanding of chondrogenesis and ossification may lead to the design of superior methods of encouraging fusion in these patients; however, at the present time, long-term maintenance in a halo brace may, in fact, be the only treatment.

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Arjun Sahgal, Mark Bilsky, Eric L. Chang, Lijun Ma, Yoshiya Yamada, Laurence D. Rhines, Daniel Létourneau, Matthew Foote, Eugene Yu, David A. Larson, and Michael G. Fehlings

Stereotactic body radiotherapy (SBRT) for spinal metastases is an emerging therapeutic option aimed at delivering high biologically effective doses to metastases while sparing the adjacent normal tissues. This technique has emerged following advances in radiation delivery that include sophisticated radiation treatment planning software, body immobilization devices, and capabilities of detecting and correcting patient positional deviations with imageguided radiotherapy. There are limited clinical data specifically supporting the role of SBRT as a superior alternative to conventional radiation in the postoperative patient. The focus of this review was to examine the evidence pertaining to spine SBRT in the treatment of spinal metastases and to provide a comprehensive analysis of published patterns of failure, with emphasis on the postoperative patient.

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Shelly X. Bian, David Routman, Jonathan Liu, Dongyun Yang, Susan Groshen, Gabriel Zada, Nicholas Trakul, Michael K. Wong, Cheng Yu, and Eric L. Chang

OBJECTIVE

Stereotactic radiosurgery (SRS) is routinely used to treat brain metastases from melanoma due to their radioresistant nature. The median survival for these patients is 4–6 months, according to earlier studies. The aim of this study was to evaluate prognostic factors that influence survival in patients with metastatic melanoma to the brain treated with SRS.

METHODS

This retrospective analysis included all patients with melanoma brain metastases treated with SRS at the University of Southern California between 1994 and 2015. For the entire cohort, the authors performed a multivariable Cox regression analysis with an end point of survival. Covariates included number of lesions, total intracranial tumor volume, age, sex, and treatment date prior to 2005 or 2005 onward.

In the subset of patients with > 1 lesion, additional multivariable Cox regression was performed, with covariates of Karnofsky Performance Scale, Graded Prognostic Assessment, Recursive Partitioning Analysis, timing of metastases (synchronous/metachronous), change in lesion number, and previous whole-brain radiation therapy or resection in addition to the previously mentioned covariates. Overall survival (OS) was calculated from the day SRS was performed to the date of last follow-up or date of death.

RESULTS

A total of 401 patients were available for analysis. The median follow-up was 35.1 months for patients alive at the time of analysis, and the median OS was 7.7 months for the entire cohort (95% CI 6.7–8.3 months). In the entire cohort, greater number of brain lesions, higher total intracranial tumor volume, age > 50 years, treatment prior to 2005, and male sex were found to be statistically significant factors associated with worse survival. The strongest risk factors for decreased OS were tumor volume > 10 cm3 and ≥ 5 lesions, with hazard ratios for risk of death of 1.7 and 2.2, respectively. In the subset of patients with > 1 lesion, tumor volume > 10 cm3 and no resection were the only factors significantly associated with decreased OS, with hazard ratios of 1.9 and 2.0 (hazard ratio of 0.49 for resection), respectively.

CONCLUSIONS

This study suggests that greater lesion number, higher intracranial tumor volume, older age, treatment prior to 2005, and male sex have prognostic significance for decreased OS in patients with melanoma brain metastases treated with SRS. Additionally, in the subset of patients with > 1 lesion, only higher total tumor volume and no resection were associated with worse survival.

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Nicholas S. Boehling, David R. Grosshans, Pamela K. Allen, Mary F. McAleer, Allen W. Burton, Syed Azeem, Laurence D. Rhines, and Eric L. Chang

Object

The aim of this study was to identify potential risk factors for and determine the rate of vertebral compression fracture (VCF) after intensity-modulated, near-simultaneous, CT image–guided stereotactic body radiotherapy (SBRT) for spinal metastases.

Methods

The study group consisted of 123 vertebral bodies (VBs) in 93 patients enrolled in prospective protocols for metastatic disease. Data from these patients were retrospectively analyzed. Stereotactic body radiotherapy consisted of 1, 3, or 5 fractions for overall median doses of 18, 27, and 30 Gy, respectively. Magnetic resonance imaging studies, obtained at baseline and at each follow-up, were evaluated for VCFs, tumor involvement, and radiographic progression. Self-reported average pain levels were scored based on the 11-point (0–10) Brief Pain Inventory both at baseline and at follow-up. Obesity was defined as a body mass index ≥ 30.

Results

The median imaging follow-up was 14.9 months (range 1–71 months). Twenty-five new or progressing fractures (20%) were identified, and the median time to progression was 3 months after SBRT. The most common histologies included renal cancer (36 VBs, 10 fractures, 10 tumor progressions), breast cancer (20 VBs, 0 fractures, 5 tumor progressions), thyroid cancer (14 VBs, 1 fracture, 2 tumor progressions), non–small cell lung cancer (13 VBs, 3 fractures, 3 tumor progressions), and sarcoma (9 VBs, 2 fractures, 2 tumor progressions). Fifteen VBs were treated with kyphoplasty or vertebroplasty after SBRT, with 5 procedures done for preexisting VCFs. Tumor progression was noted in 32 locations (26%) with 5 months' median time to progression. At the time of noted fracture progression there was a trend toward higher average pain scores but no significant change in the median value. Univariate logistic regression showed that an age > 55 years (HR 6.05, 95% CI 2.1–17.47), a preexisting fracture (HR 5.05, 95% CI 1.94–13.16), baseline pain and narcotic use before SBRT (pain: HR 1.31, 95% CI 1.06–1.62; narcotic: HR 2.98, 95% CI 1.17–7.56) and after SBRT (pain: HR 1.34, 95% CI 1.06–1.70; narcotic: HR 3.63, 95% CI 1.41–9.29) were statistically significant predictors of fracture progression. On multivariate analysis an age > 55 years (HR 10.66, 95% CI 2.81–40.36), a preexisting fracture (HR 9.17, 95% CI 2.31–36.43), and baseline pain (HR 1.41, 95% CI 1.05–1.9) were found to be significant risks, whereas obesity (HR 0.02, 95% CI 0–0.2) was protective.

Conclusions

Stereotactic body radiotherapy is associated with a significant risk (20%) of VCF. Risk factors for VCF include an age > 55 years, a preexisting fracture, and baseline pain. These risk factors may aid in the selection of which spinal SBRT patients should be considered for prophylactic vertebral stabilization or augmentation procedures. Clinical trial registration no.: NCT00508443.