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

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Yimo Lin, I-Wen Pan, Rory R. Mayer, and Sandi Lam

OBJECT

Research conducted using large administrative data sets has increased in recent decades, but reports on the fidelity and reliability of such data have been mixed. The goal of this project was to compare data from a large, administrative claims data set with a quality improvement registry in order to ascertain similarities and differences in content.

METHODS

Data on children younger than 12 months with nonsyndromic craniosynostosis who underwent surgery in 2012 were queried in both the Kids’ Inpatient Database (KID) and the American College of Surgeons Pediatric National Surgical Quality Improvement Program (Peds NSQIP). Data from published clinical craniosynostosis surgery series are reported for comparison.

RESULTS

Among patients younger than 12 months of age, a total of 1765 admissions were identified in KID and 391 in Peds NSQIP in 2012. Only nonsyndromic patients were included. The mean length of stay was 3.2 days in KID and 4 days in Peds NSQIP. The rates of cardiac events (0.5% in KID, 0.3% in Peds NSQIP, and 0.4%-2.2% in the literature), stroke/intracranial bleeds (0.4% in KID, 0.5% in Peds NSQIP, and 0.3%-1.2% in the literature), infection (0.2% in KID, 0.8% in Peds NSQIP, and 0%-8% in the literature), wound disruption (0.2% in KID, 0.5% in Peds NSQIP, 0%-4% in the literature), and seizures (0.7% in KID, 0.8% in Peds NSQIP, 0%-0.8% in the literature) were low and similar between the 2 data sets. The reported rates of blood transfusion (36% in KID, 64% in Peds NSQIP, and 1.7%-100% in the literature) varied between the 2 data sets.

CONCLUSIONS

Both the KID and Peds NSQIP databases provide large samples of surgical patients, with more cases reported in KID. The rates of complications studied were similar between the 2 data sets, with the exception of blood transfusion events where the retrospective chart review process of Peds NSQIP captured almost double the rate reported in KID.

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Zhuo Xi, Shane Burch, Praveen V. Mummaneni, Rory Richard Mayer, Charles Eichler, and Dean Chou

OBJECTIVE

Obese patients have been shown to have longer operative times and more complications from surgery. However, for obese patients undergoing minimally invasive surgery, these differences may not be as significant. In the lateral position, it is thought that obesity is less of an issue because gravity pulls the visceral fat away from the spine; however, this observation is primarily anecdotal and based on expert opinion. The authors performed oblique lumbar interbody fusion (OLIF) and they report on the perioperative morbidity in obese and nonobese patients.

METHODS

The authors conducted a retrospective review of patients who underwent OLIF performed by 3 spine surgeons and 1 vascular surgeon at the University of California, San Francisco, from 2013 to 2018. Data collected included demographic variables; approach-related factors such as operative time, blood loss, and expected temporary approach-related sequelae; and overall complications. Patients were categorized according to their body mass index (BMI). Obesity was defined as a BMI ≥ 30 kg/m2, and severe obesity was defined as a BMI ≥ 35 kg/m2.

RESULTS

There were 238 patients (95 males and 143 females). There were no significant differences between the obese and nonobese groups in terms of sex, levels fused, or smoking status. For the entire cohort, there was no difference in operative time, blood loss, or complications when comparing obese and nonobese patients. However, a subset analysis of the 77 multilevel OLIFs that included L5–S1 demonstrated that the operative times for the nonobese group was 223.55 ± 57.93 minutes, whereas it was 273.75 ± 90.07 minutes for the obese group (p = 0.004). In this subset, the expected approach-related sequela rate was 13.2% for the nonobese group, whereas it was 33.3% for the obese group (p = 0.039). However, the two groups had similar blood loss (p = 0.476) and complication rates (p = 0.876).

CONCLUSIONS

Obesity and morbid obesity generally do not increase the operative time, blood loss, approach-related sequelae, or complications following OLIF. However, obese patients who undergo multilevel OLIF that includes the L5–S1 level do have longer operative times or a higher rate of expected approach-related sequelae. Obesity should not be considered a contraindication to multilevel OLIF, but patients should be informed of potentially increased morbidity if the L5–S1 level is to be included.

Open access

Chih-Chang Chang, Praveen V. Mummaneni, Joshua Rivera, Rory Mayer, and Dean Chou

Iatrogenic flat back deformity generally can be treated with a pedicle subtraction osteotomy (PSO) (Chan et al., 2018; Lu and Chou, 2007). One of the difficulties with PSO is that a controlled closure can sometimes be problematic in that there may be translation of the spine, manual pushing of the spine, and significant stress on the pedicle screws, which may risk loosening. The authors present a video of their surgical technique for PSO closed by passive closure using an open-bottom hinged table. This allows the osteotomy to be closed without any force on the screws and without significant manual forces on the spinal column.

The video can be found here: https://youtu.be/pUECEjKdmSk.

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Sandi K. Lam, Christian M. Niedzwecki, Bradley Daniels, Rory R. Mayer, Mili M. Vakharia, and Andrew Jea

Pediatric idiopathic intervertebral disc calcification (PIIVDC) is a rare condition; most cases are reported to be selflimited with conservative management. In this study, we describe a case of PIIVDC presenting with acute incomplete spinal cord injury with Brown-Séquard-plus syndrome that was treated with surgery and demonstrate the subsequent rehabilitation time course.

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Ping-Guo Duan, Praveen V. Mummaneni, Minghao Wang, Andrew K. Chan, Bo Li, Rory Mayer, Sigurd H. Berven, and Dean Chou

OBJECTIVE

In this study, the authors’ aim was to investigate whether obesity affects surgery rates for adjacent-segment degeneration (ASD) after transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis.

METHODS

Patients who underwent single-level TLIF for spondylolisthesis at the University of California, San Francisco, from 2006 to 2016 were retrospectively analyzed. Inclusion criteria were a minimum 2-year follow-up, single-level TLIF, and degenerative lumbar spondylolisthesis. Exclusion criteria were trauma, tumor, infection, multilevel fusions, non-TLIF fusions, or less than a 2-year follow-up. Patient demographic data were collected, and an analysis of spinopelvic parameters was performed. The patients were divided into two groups: mismatched, or pelvic incidence (PI) minus lumbar lordosis (LL) ≥ 10°; and balanced, or PI-LL < 10°. Within the two groups, the patients were further classified by BMI (< 30 and ≥ 30 kg/m2). Patients were then evaluated for surgery for ASD, matched by BMI and PI-LL parameters.

RESULTS

A total of 190 patients met inclusion criteria (72 males and 118 females, mean age 59.57 ± 12.39 years). The average follow-up was 40.21 ± 20.42 months (range 24–135 months). In total, 24 patients (12.63% of 190) underwent surgery for ASD. Within the entire cohort, 82 patients were in the mismatched group, and 108 patients were in the balanced group. Within the mismatched group, adjacent-segment surgeries occurred at the following rates: BMI < 30 kg/m2, 2.1% (1/48); and BMI ≥ 30 kg/m2, 17.6% (6/34). Significant differences were seen between patients with BMI ≥ 30 and BMI < 30 (p = 0.018). A receiver operating characteristic curve for BMI as a predictor for ASD was established, with an AUC of 0.69 (95% CI 0.49–0.90). The optimal BMI cutoff value determined by the Youden index is 29.95 (sensitivity 0.857; specificity 0.627). However, in the balanced PI-LL group (108/190 patients), there was no difference in surgery rates for ASD among the patients with different BMIs (p > 0.05).

CONCLUSIONS

In patients who have a PI-LL mismatch, obesity may be associated with an increased risk of surgery for ASD after TLIF, but in obese patients without PI-LL mismatch, this association was not observed.

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Minghao Wang, Praveen V. Mummaneni, Zhuo Xi, Chih-Chang Chang, Joshua Rivera, Jeremy Guinn, Rory Mayer, and Dean Chou

OBJECTIVE

A consequence of anterior cervical discectomy and fusion (ACDF) is graft subsidence, potentially leading to kyphosis, nonunion, foraminal stenosis, and recurrent pain. Bone density, as measured in Hounsfield units (HUs) on CT, may be associated with subsidence. The authors evaluated the association between HUs and subsidence rates after ACDF.

METHODS

A retrospective study of patients treated with single-level ACDF at the University of California, San Francisco, from 2008 to 2017 was performed. HU values were measured according to previously published methods. Only patients with preoperative CT, minimum 1-year follow-up, and single-level ACDF were included. Patients with posterior surgery, tumor, infection, trauma, deformity, or osteoporosis treatment were excluded. Changes in segmental height were measured at 1-year follow-up compared with immediate postoperative radiographs. Subsidence was defined as segmental height loss of more than 2 mm.

RESULTS

A total of 91 patients met inclusion criteria. There was no significant difference in age or sex between the subsidence and nonsubsidence groups. Mean HU values in the subsidence group (320.8 ± 23.9, n = 8) were significantly lower than those of the nonsubsidence group (389.1 ± 53.7, n = 83, p < 0.01, t-test). There was a negative correlation between the HU values and segmental height loss (Pearson’s coefficient −0.735, p = 0.01). Using receiver operating characteristic curves, the area under the curve was 0.89, and the most appropriate threshold of HU value was 343.7 (sensitivity 77.1%, specificity 87.5%). A preoperative lower HU is a risk factor for postoperative subsidence (binary logistic regression, p < 0.05). The subsidence rate and distance between allograft and polyetheretherketone (PEEK) materials were not significantly different (PEEK 0.9 ± 0.7 mm, allograft 1.0 ± 0.7 mm; p > 0.05).

CONCLUSIONS

Lower preoperative CT HU values are associated with cage subsidence in single-level ACDF. Preoperative measurement of HUs may be useful in predicting outcomes after ACDF.

Free access

Ziev B. Moses, Rory R. Mayer, Benjamin A. Strickland, Ryan M. Kretzer, Jean-Paul Wolinsky, Ziya L. Gokaslan, and Ali A. Baaj

Object

Parallel advancements in image guidance technology and minimal access techniques continue to push the frontiers of minimally invasive spine surgery (MISS). While traditional intraoperative imaging remains widely used, newer platforms, such as 3D-fluoroscopy, cone-beam CT, and intraoperative CT/MRI, have enabled safer, more accurate instrumentation placement with less radiation exposure to the surgeon. The goal of this work is to provide a review of the current uses of advanced image guidance in MISS.

Methods

The authors searched PubMed for relevant articles concerning MISS, with particular attention to the use of image-guidance platforms. Pertinent studies published in English were further compiled and characterized into relevant analyses of MISS of the cervical, thoracic, and lumbosacral regions.

Results

Fifty-two studies were included for review. These describe the use of the iso-C system for 3D navigation during C1–2 transarticular screw placement, the use of endoscopic techniques in the cervical spine, and the role of navigation guidance at the occipital-cervical junction. The authors discuss the evolving literature concerning neuronavigation during pedicle screw placement in the thoracic and lumbar spine in the setting of infection, trauma, and deformity surgery and review the use of image guidance in transsacral approaches.

Conclusions

Refinements in image-guidance technologies and minimal access techniques have converged on spinal pathology, affording patients the ability to undergo safe, accurate operations without the associated morbidities of conventional approaches. While percutaneous transpedicular screw placement is among the most common procedures to benefit from navigation, other areas of spine surgery can benefit from advances in neuronavigation and further growth in the field of image-guided MISS is anticipated.

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Rory R. Mayer, Steven W. Hwang, Gaddum D. Reddy, David L. Morales, William E. Whitehead, Daniel J. Curry, Robert J. Bollo, Thomas G. Luerssen, and Andrew Jea

Object

Left ventricular assist devices (LVADs) are continuous or pulsatile flow devices that could potentially be life-saving measures for patients with end-stage heart failure. These devices have clear advantages over extracorporeal membrane oxygenation (ECMO) and are often used in adults. They are only recently being commonly used in the pediatric age group. As the use of LVADs becomes more mainstream in children, it is important to determine the complication profile associated with these devices. Furthermore, with the increasing application of LVADs in children, pediatric neurosurgeons are seeing a correlative increase in associated neurological complications. In this study, the authors reviewed the incidence of neurological complications due to LVAD use in the pediatric age group and the role of neurosurgery in treatment.

Methods

The authors examined data regarding patients with LVADs from the Texas Children's Hospital Heart Center database (July 01, 2007, to June 30, 2011) and recorded neurological complications requiring neurosurgical consultation. They identified 2 children who underwent craniotomies during LVAD treatment.

Results

Intracranial hemorrhage occurred in 3 (6.5%) of the 46 patients treated with an LVAD at the authors' institution. Of these patients, 2 were treated with craniotomies for life-threatening intracranial hemorrhages. The 3 patients in the neurosurgical cohort presented with cerebral infarction, decreased level of consciousness, and/or seizure. At the last follow-up (286, 503, and 550 days), 1 patient (Case 2) had no decline in neurological status, underwent a successful heart transplant, and was discharged home; 1 patient (Case 1) died of refractory cardiac failure; and 1 patient (Case 3) was on an LVAD for destination therapy (that is, the LVAD is not a bridge to transplantation but rather the final treatment). This patient was discharged from the hospital, but he died of overwhelming fungemia at 286 days while on VAD support.

Conclusions

Intracranial hemorrhage is a serious and feared complication of LVAD treatment. While the surgical risk is substantial due to systemic anticoagulation and significant medical comorbidities, neurosurgical evacuation of hemorrhage plays an important life-saving role that can yield successful and acceptable outcomes.

Free access

John F. Burke, Andrew K. Chan, Rory R. Mayer, Joseph H. Garcia, Brenton Pennicooke, Michael Mann, Sigurd H. Berven, Dean Chou, and Praveen V. Mummaneni

The clamshell thoracotomy is often used to access both hemithoraxes and the mediastinum simultaneously for cardiothoracic pathology, but this technique is rarely used for the excision of spinal tumors. We describe the use of a clamshell thoracotomy for en bloc excision of a 3-level upper thoracic chordoma in a 20-year-old patient. The lesion involved T2, T3, and T4, and it invaded both chest cavities and indented the mediastinum. After 2 biopsies to confirm the diagnosis, the patient underwent a posterior spinal fusion followed by bilateral clamshell thoracotomy for 3-level en bloc resection with simultaneous access to both chest cavities and the mediastinum. To demonstrate how the clamshell thoracotomy was used to facilitate the tumor resection, an operative video and illustrations are provided, which show in detail how the clamshell thoracotomy can be used to access both hemithoraxes and the mediastinum.