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Andrew K. Chan, Ethan A. Winkler and Line Jacques

OBJECTIVE

Cervical spinal cord stimulation (cSCS) is used to treat pain of the cervical region and upper extremities. Case reports and small series have shown a relatively low risk of complication after cSCS, with only a single reported case of perioperative spinal cord injury in the literature. Catastrophic cSCS-associated spinal cord injury remains a concern as a result of underreporting. To aid in preoperative counseling, it is necessary to establish a minimum rate of spinal cord injury and surgical complication following cSCS.

METHODS

The Nationwide Inpatient Sample (NIS) is a stratified sample of 20% of all patient discharges from nonfederal hospitals in the United States. The authors identified discharges with a primary procedure code for spinal cord stimulation (ICD-9 03.93) associated with a primary diagnosis of cervical pathology from 2002 to 2011. They then analyzed short-term safety outcomes including the presence of spinal cord injury and neurological, medical, and general perioperative complications and compared outcomes using univariate analysis.

RESULTS

Between 2002 and 2011, there were 2053 discharges for cSCS. The spinal cord injury rate was 0.5%. The rates of any neurological, medical, and general perioperative complications were 1.1%, 1.4%, and 11.7%, respectively. There were no deaths.

CONCLUSIONS

In the largest series of cSCS, the risk of spinal cord injury was higher than previously reported (0.5%). Nonetheless, this procedure remains relatively safe, and physicians may use these data to corroborate the safety of cSCS in an appropriately selected patient population. This may become a key treatment option in an increasingly opioid-dependent, aging population.

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Andrew K. Chan, Rory R. Mayer, Praveen V. Mummaneni and Dean Chou

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Darryl Lau, Andrew K. Chan, Vedat Deverin and Christopher P. Ames

OBJECTIVE

Adult spinal deformity (ASD) develops in the setting of asymmetrical arthritic degeneration, and can also be due to iatrogenic causes, such as prior surgery. Many patients who present with ASD have undergone prior spine surgery with instrumentation. Unfortunately, contemporary studies that evaluate the effect of prior surgery or instrumentation on perioperative outcomes, readmission rates, and need for reoperation are lacking.

METHODS

All ASD patients who underwent a 3-column osteotomy performed by the senior author at the authors’ institution for correction of thoracolumbar spinal deformity between 2006 and 2016 were identified. The authors compared surgical outcomes between primary (first-time) and revision cases. Further subgroup analysis was conducted to investigate the effect of the number of prior surgeries (0, 1, 2, 3, 4, and 5 or more) and the presence of spinal instrumentation on outcomes. Multivariate analysis was used to adjust for relevant and significant confounders.

RESULTS

A total of 300 patients were included; 38.3% of patients were male. The overall perioperative complication rate was 24.7%, and the mean length of hospitalization was 8.2 days. The 90-day readmission rate was 9.0%, and the overall follow-up reoperation rate was 26.7%. There were no significant differences in complication rates (26.6% vs 24.0%, p = 0.645), length of hospitalization (8.7 vs 7.9 days, p = 0.229), readmission rates (11.4% vs 8.1%, p = 0.387), or reoperation rates (26.6% vs 26.7%, p = 0.984) between primary and revision cases. There was no significant difference in wound complications (infections/dehiscence) requiring reoperation (5.1% vs 6.3%, p = 0.683). Subgroup analysis conducted to evaluate the effect of the number of prior spinal surgeries or the presence of spinal instrumentation did not reveal significant differences for the aforementioned surgical outcomes. In adjusted multivariate analysis, there were no significant associations between history of prior surgery (number of prior surgeries and prior instrumentation) and all of the surgical outcomes of interest.

CONCLUSIONS

The findings from this study suggest that patients who have undergone prior spine surgery with or without instrumentation are not at increased risk for perioperative complications, need for readmission, or reoperation following 3-column osteotomy of the thoracolumbar spine.

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Andrew K. Chan, Alvin Y. Chan, Darryl Lau, Beata Durcanova, Catherine A. Miller, Paul S. Larson, Philip A. Starr and Praveen V. Mummaneni

OBJECTIVE

Camptocormia is a potentially debilitating condition in the progression of Parkinson’s disease (PD). It is described as an abnormal forward flexion while standing that resolves when lying supine. Although the condition is relatively common, the underlying pathophysiology and optimal treatment strategy are unclear. In this study, the authors systematically reviewed the current surgical management strategies for camptocormia.

METHODS

PubMed was queried for primary studies involving surgical intervention for camptocormia in PD patients. Studies were excluded if they described nonsurgical interventions, provided only descriptive data, or were case reports. Secondarily, data from studies describing deep brain stimulation (DBS) to the subthalamic nuclei were extracted for potential meta-analysis. Variables showing correlation to improvement in sagittal plane bending angle (i.e., the vertical angle caused by excessive kyphosis) were subjected to formal meta-analysis.

RESULTS

The query resulted in 9 studies detailing treatment of camptocormia: 1 study described repetitive trans-spinal magnetic stimulation (rTSMS), 7 studies described DBS, and 1 study described deformity surgery. Five studies were included for meta-analysis. The total number of patients was 66. The percentage of patients with over 50% decrease in sagittal plane imbalance with DBS was 36.4%. A duration of camptocormia of 2 years or less was predictive of better outcomes (OR 4.15).

CONCLUSIONS

Surgical options include transient, external spinal stimulation; DBS targeting the subthalamic nuclei; and spinal deformity surgery. Benefit from DBS stimulation was inconsistent. Spine surgery corrected spinal imbalance but was associated with a high complication rate.

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Brett E. Youngerman, Andrew K. Chan, Charles B. Mikell, Guy M. McKhann and Sameer A. Sheth

OBJECTIVE

Deep brain stimulation (DBS) is an emerging treatment option for an expanding set of neurological and psychiatric diseases. Despite growing enthusiasm, the patterns and implications of this rapid adoption are largely unknown. National trends in DBS surgery performed for all indications between 2002 and 2011 are reported.

METHODS

Using a national database of hospital discharges, admissions for DBS for 14 indications were identified and categorized as either FDA approved, humanitarian device exempt (HDE), or emerging. Trends over time were examined, differences were analyzed by univariate analyses, and outcomes were analyzed by hierarchical regression analyses.

RESULTS

Between 2002 and 2011, there were an estimated 30,490 discharges following DBS for approved indications, 1647 for HDE indications, and 2014 for emerging indications. The volume for HDE and emerging indications grew at 36.1% annually in comparison with 7.0% for approved indications. DBS for emerging indications occurred at hospitals with more neurosurgeons and neurologists locally, but not necessarily at those with the highest DBS caseloads. Patients treated for HDE and emerging indications were younger with lower comorbidity scores. HDE and emerging indications were associated with greater rates of reported complications, longer lengths of stay, and greater total costs.

CONCLUSIONS

DBS for HDE and emerging indications underwent rapid growth in the last decade, and it is not exclusively the most experienced DBS practitioners leading the charge to treat the newest indications. Surgeons may be selecting younger and healthier patients for their early experiences. Differences in reported complication rates warrant further attention and additional costs should be anticipated as surgeons gain experience with new patient populations and targets.

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Minghao Wang, Dean Chou, Chih-Chang Chang, Ankit Hirpara, Yilin Liu, Andrew K. Chan, Brenton Pennicooke and Praveen V. Mummaneni

OBJECTIVE

Both structural allograft and PEEK have been used for anterior cervical discectomy and fusion (ACDF). There are reports that PEEK has a higher pseudarthrosis rate than structural allograft. The authors compared pseudarthrosis, revision, subsidence, and loss of lordosis rates in patients with PEEK and structural allograft.

METHODS

The authors performed a retrospective review of patients who were treated with ACDF at their hospital between 2005 and 2017. Inclusion criteria were adult patients with either PEEK or structural allograft, anterior plate fixation, and a minimum 2-year follow-up. Exclusion criteria were hybrid PEEK and allograft cases, additional posterior surgery, adjacent corpectomies, infection, tumor, stand-alone or integrated screw and cage devices, bone morphogenetic protein use, or lack of a minimum 2-year follow-up. Demographic variables, number of treated levels, interbody type (PEEK cage vs structural allograft), graft packing material, pseudarthrosis rates, revision surgery rates, subsidence, and cervical lordosis changes were collected. These data were analyzed by Pearson’s chi-square test (or Fisher’s exact test, according to the sample size and expected value) and Student t-test.

RESULTS

A total of 168 patients (264 levels total, mean follow-up time 39.5 ± 24.0 months) were analyzed. Sixty-one patients had PEEK, and 107 patients had structural allograft. Pseudarthrosis rates for 1-level fusions were 5.4% (PEEK) and 3.4% (allograft) (p > 0.05); 2-level fusions were 7.1% (PEEK) and 8.1% (allograft) (p > 0.05); and ≥ 3-level fusions were 10% (PEEK) and 11.1% (allograft) (p > 0.05). There was no statistical difference in the subsidence magnitude between PEEK and allograft in 1-, 2-, and ≥ 3-level ACDF (p > 0.05). Postoperative lordosis loss was not different between cohorts for 1- and 2-level surgeries.

CONCLUSIONS

In 1- and 2-level ACDF with plating involving the same number of fusion levels, there was no statistically significant difference in the pseudarthrosis rate, revision surgery rate, subsidence, and lordosis loss between PEEK cages and structural allograft.

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Robert A. McGovern, Kathleen M. Kelly, Andrew K. Chan, Nicholas J. Morrissey and Guy M. McKhann II

Object

Ventriculoatrial (VA) shunting is rarely used for patients with normal-pressure hydrocephalus (NPH), likely due to surgeon technical preference and case reports indicating cardiopulmonary complications. However, these complications have typically been limited to adults in whom VA shunts had been placed when they were children. Few studies have directly compared VA shunting to ventriculoperitoneal (VP) shunting in cases of NPH.

Methods

The authors retrospectively analyzed all NPH patients treated by a single surgeon at their center from January 2002 through December 2011. Thirty patients were treated with VA shunts (14 male) and 157 with VP shunts (86 male). The patients' mean age (± SD) at surgery was 73.7 ± 9.4 years for VA shunting and 76.0 ± 8.2 years for VP shunting; the median durations of follow-up were 42.0 months (IQR 19.2–63.6 months) and 34.2 months (IQR 15.8–67.5), respectively. Statistical analysis was performed using chi-square tests and Wilcoxon rank-sum tests.

Results

Perioperative and postoperative complications for VA and VP shunting cohorts, respectively, included distal revision (2.7% vs 6.6%, p = 0.45), proximal revision (2.7% vs 2.5%, p = 0.97), and postoperative seizure (2.7% vs 1.5%, p = 0.62). Shunt drainage–related subdural hematomas/hygromas developed in 8.1%/27.0% of VA shunt–treated patients versus 6.6%/26.4% of VP shunt–treated patients (p = 0.76/0.98) and were nearly always successfully managed with programmable-valve adjustment. Symptomatic intracerebral hemorrhage (1.5%) and shunt infection (2.0%) were only observed in those who underwent VP shunting. Of note, no cardiovascular complications were observed in any patient, and there were no cases of distal occlusion of the VA shunt.

Conclusions

The authors found no significant differences in complication rates between VA and VP shunting, and VA shunting was not associated with any cardiopulmonary complications. Thus, in the authors' experience, VA shunting is at least as safe as VP shunting for treating NPH.

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Robert A. McGovern, John P. Sheehy, Brad E. Zacharia, Andrew K. Chan, Blair Ford and Guy M. McKhann II

Object

Early work on deep brain stimulation (DBS) surgery, when procedures were mostly carried out in a small number of high-volume centers, demonstrated a relationship between surgical volume and procedural safety. However, over the past decade, DBS has become more widely available in the community rather than solely at academic medical centers. The authors examined the Nationwide Inpatient Sample (NIS) to study the safety of DBS surgery for Parkinson disease (PD) in association with this change in practice patterns.

Methods

The NIS is a stratified sample of 20% of all patient discharges from nonfederal hospitals in the United States. The authors identified patients with a primary diagnosis of PD (332.0) and a primary procedure code for implantation/replacement of intracranial neurostimulator leads (02.93) who underwent surgery between 2002 and 2009. They analyzed outcomes using univariate and hierarchical, logistic regression analyses.

Results

The total number of DBS cases remained stable from 2002 through 2009. Despite older and sicker patients undergoing DBS, procedural safety (rates of non-home discharges, complications) remained stable. Patients at low-volume hospitals were virtually indistinguishable from those at high-volume hospitals, except that patients at low-volume hospitals had slightly higher comorbidity scores (0.90 vs 0.75, p < 0.01). Complications, non-home discharges, length of hospital stay, and mortality rates did not significantly differ between low- and high-volume hospitals when accounting for hospital-related variables (caseload, teaching status, location).

Conclusions

Prior investigations have demonstrated a robust volume-outcome relationship for a variety of surgical procedures. However, the present study supports safety of DBS at smaller-volume centers. Prospective studies are required to determine whether low-volume centers and higher-volume centers have similar DBS efficacy, a critical factor in determining whether DBS is comparable between centers.

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Darryl Lau, Andrew K. Chan, Alexander A. Theologis, Dean Chou, Praveen V. Mummaneni, Shane Burch, Sigurd Berven, Vedat Deviren and Christopher Ames

OBJECTIVE

Because the surgical strategies for primary and metastatic spinal tumors are different, the respective associated costs and morbidities associated with those treatments likely vary. This study compares the direct costs and 90-day readmission rates between the resection of extradural metastatic and primary spinal tumors. The factors associated with cost and readmission are identified.

METHODS

Adults (age 18 years or older) who underwent the resection of spinal tumors between 2008 and 2013 were included in the study. Patients with intradural tumors were excluded. The direct costs of index hospitalization and 90-day readmission hospitalization were evaluated. The direct costs were compared between patients who were treated surgically for primary and metastatic spinal tumors. The independent factors associated with costs and readmissions were identified using multivariate analysis.

RESULTS

A total of 181 patients with spinal tumors were included (63 primary and 118 metastatic tumors). Overall, the mean index hospital admission cost for the surgical management of spinal tumors was $52,083. There was no significant difference in the cost of hospitalization between primary ($55,801) and metastatic ($50,098) tumors (p = 0.426). The independent factors associated with higher cost were male sex (p = 0.032), preoperative inability to ambulate (p = 0.002), having more than 3 comorbidities (p = 0.037), undergoing corpectomy (p = 0.021), instrumentation greater than 7 levels (p < 0.001), combined anterior-posterior approach (p < 0.001), presence of a perioperative complication (p < 0.001), and longer hospital stay (p < 0.001). The perioperative complication rate was 21.0%. Of this cohort, 11.6% of patients were readmitted within 90 days, and the mean hospitalization cost of that readmission was $20,078. Readmission rates after surgical treatment for primary and metastatic tumors were similar (11.1% vs 11.9%, respectively) (p = 0.880). Prior hospital stay greater than 15 days (OR 6.62, p = 0.016) and diagnosis of lung metastasis (OR 52.99, p = 0.007) were independent predictors of readmission.

CONCLUSIONS

Primary and metastatic spinal tumors are comparable with regard to the direct costs of the index surgical hospitalization and readmission rate within 90 days. The factors independently associated with costs are related to preoperative health status, type and complexity of surgery, and postoperative course.