Daniel Blizzard | Duke University School of Medicine (original) (raw)

Papers by Daniel Blizzard

Research paper thumbnail of Routine Anteroposterior Radiographs Have Limited Utility for Patients After Anterior Cervical Decompression and Fusion

Spine, Oct 15, 2012

A retrospective case series. To assess the diagnostic utility of sequential anteroposterior (AP) ... more A retrospective case series. To assess the diagnostic utility of sequential anteroposterior (AP) radiographs for following patients with postoperative anterior cervical decompression and fusion (ACDF). There are currently no widely accepted standards for radiographical follow-up after ACDF. Many spine surgeons routinely obtain at least AP and lateral films at serial follow-up visits. It is generally accepted that lateral films are of utility to assess overall alignment, evaluate union, and detect any potential construct-related issues. It is our perception that the AP view adds little or no clinical value after documentation of alignment on an initial film. All follow-up imaging series were evaluated for 100 patients who underwent ACDF. Variables thought to be potentially detected on the AP film were evaluated on both the AP and lateral films (visualization of the implant and instrumented vertebral bodies and any construct-related issues). In addition, angulation of the implant relative to the vertebral axis of the instrumented levels was measured on the AP film. For the 100 patients evaluated, the follow-up period was 1.2 ± 0.5 months (mean ± SD), with 4.39 ± 1.52 imaging series obtained per patient. Instrumented vertebral bodies were fully visualized in 99.5% of AP and 86.7% of lateral films obtained at follow-up visits. The entire implant was visualized in 100% of AP films and 95.6% of lateral films. No hardware-related issues were seen (screw disengagement, pullout, breakage, etc.). No patients were found to have progression of coronal plate angulation beyond 3° at their last follow-up series relative to the first follow-up visit. Using rigorous evaluation methods, we found no significant incremental utility of AP films obtained in addition to lateral films. Therefore, given the inherent cost, time, and radiation exposure associated with each additional view, we propose that AP films should not be part of routine follow-up imaging after ACDF.

Research paper thumbnail of Cervical myelopathy doubles the rate of dislocation and fracture after total hip arthroplasty

The Journal of Arthroplasty, 2016

Cervical spondylotic myelopathy (CSM) is a common and underdiagnosed cause of gait dysfunction, r... more Cervical spondylotic myelopathy (CSM) is a common and underdiagnosed cause of gait dysfunction, rigidity, and falls in the elderly. Given the frequent concurrency of CSM and hip osteoarthritis, this study is designed to evaluate the relative risk of CSM on perioperative and short-term outcomes after total hip arthroplasty (THA). The Medicare Standard Analytical Files were searched from 2005 to 2012 to identify all patients undergoing primary THA and the subset of patients with preexisting CSM. Risk ratios with 95% confidence intervals were calculated for 90-day, 1-year, and overall follow-up for common postoperative complications: periprosthetic dislocation, fracture, infection, revision THA, and wound complications. The risk ratios of all surgical complications, including dislocation, periprosthetic fractures, and prosthetic joint infection, were increased approximately 2-fold at all postoperative time points for patients. Preexisting CSM is a significant risk factor for primary THA complications including dislocation, periprosthetic fractures, and prosthetic joint infection.

Research paper thumbnail of Renal artery injury during lateral transpsoas interbody fusion: case report

Journal of neurosurgery. Spine, Jan 20, 2016

Lateral interbody fusion (LIF) via the retroperitoneal transpsoas approach is an increasingly pop... more Lateral interbody fusion (LIF) via the retroperitoneal transpsoas approach is an increasingly popular, minimally invasive technique for interbody fusion in the thoracolumbar spine that avoids many of the complications of traditional anterior and transforaminal approaches. Renal vascular injury has been cited as a potential risk in LIF, but little has been documented in the literature regarding the etiology of this injury. The authors discuss a case of an intraoperative complication of renal artery injury during LIF. A 42-year-old woman underwent staged T12-L5 LIF in the left lateral decubitus position, and L5-S1 anterior lumbar interbody fusion, followed 3 days later by T12-S1 posterior instrumentation for idiopathic scoliosis with radiculopathy refractory to conservative management. After placement of the T12-L1 cage, the retractor was released and significant bleeding was encountered during its removal. Immediate consultation with the vascular team was obtained, and hemostasis was...

Research paper thumbnail of Should we think twice about psychiatric disease in total hip arthroplasty?

The Journal of Arthroplasty, 2016

Psychiatric disease (PD) is common, and the effect on complications in total hip arthroplasty (TH... more Psychiatric disease (PD) is common, and the effect on complications in total hip arthroplasty (THA) is poorly understood. The purpose of this study was to evaluate the medical and surgical postoperative complication profile in patients with PD, and we hypothesize that they will be significantly increased compared with control group. A search of the entire Medicare database from 2005 to 2011 was performed using International Classification of Disease version 9 codes to identify 86,976 patients who underwent primary THA with PD including bipolar (5626), depression (82,557), and schizophrenia (3776). A cohort of 590,689 served as a control with minimum 2-year follow-up. Medical and surgical complications at 30-day, 90-day, and overall time points were compared between the 2 cohorts. Patients with PD were more likely to be younger (age < 65 years; odds ratio [OR] = 4.51, P < .001), female (OR = 2.02, P < .001) and more medically complex (significant increase in 28/28 Elixhauser medical comorbidities, P < .001). There was a significant increase (P < .001) in 13/14 (92.8%) recorded postoperative medical complications rates at the 90-day time point. In addition, there was a statistically significant increase in periprosthetic infection (OR = 2.26, P < .001), periprosthetic fracture (OR = 2.09, P < .001), dislocation (OR = 2.30, P < .001), and THA revision (OR = 1.93, P < .001) at overall follow-up. Patients with PD who undergo elective primary THA have significantly increased medical and surgical complication rates in the global period and short-term follow-up, and these patients need to be counseled accordingly.

Research paper thumbnail of The Impact of Lumbar Spine Disease and Deformity on Total Hip Arthroplasty Outcomes

Orthopedic Clinics of North America, 2016

Concurrent spine and hip disease is common. Spinal deformities can restrict lumbar range of motio... more Concurrent spine and hip disease is common. Spinal deformities can restrict lumbar range of motion and lumbar lordosis, leading to pelvic obliquity and increased pelvic tilt. A comprehensive preoperative workup and component templating ensure appropriate compensation for altered pelvic parameters for implantation of components according to functional positioning. Pelvic obliquity from scoliosis must be measured to calculate appropriate leg length. Cup positioning should be templated on standing radiograph to limit impingement from cup malposition. In spinal deformity, the optimal position of the cup that accommodates pelvic parameters and limits impingement may lie outside the classic parameters of the safe zone.

Research paper thumbnail of Erratum to: CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European Spine Journal, 2015

Research paper thumbnail of Lumbar Spine Disease Negatively Affects Outcomes after Total Hip Arthroplasty

Research paper thumbnail of The role of iatrogenic foraminal stenosis from lordotic correction in the development of C5 palsy after posterior laminectomy and fusion

Journal of orthopaedic surgery and research, 2015

Post-operative C5 nerve root palsy is a known complication following cervical spine surgery. Alth... more Post-operative C5 nerve root palsy is a known complication following cervical spine surgery. Although several theories have been proposed, there remains no consensus as to the etiology of the palsies. Multiple pre-operative radiographic measures have been assessed for utility in predicting palsy. The purpose of this study is to evaluate published radiographic parameters as well as specifically evaluate the effect of cervical lordosis in the development of C5 palsy to establish thresholds that reliably predict the incidence. This study is a retrospective review of 54 consecutive multilevel cervical laminectomy and fusion surgeries performed by a single spine surgeon between June 2007 and February 2014. Pre-operative MRI and pre- and post-operative plain films were assessed to measure anteroposterior diameter (APD) of the spinal cord, cervical laminar angles, anteroposterior foraminal diameters (FD), cervical curvature index (Ishihara), cervical spine angle (C2-7), and C4-5 angle. Uni...

Research paper thumbnail of Erratum to: CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 12, 2015

Research paper thumbnail of C5 Nerve Palsy in Posterior Cervical Spinal Surgery: Does Width of Laminectomy Matter?

Research paper thumbnail of Is a wider cervical laminectomy a risk factor for postoperative C5 nerve palsy?

Research paper thumbnail of Radiographic Predictors of C5 Palsy Following Multilevel Cervical Laminectomy and Fusion

Research paper thumbnail of Sagital balance and lordosis correction in lateral interbody fusion

Research paper thumbnail of Interval effect of prone repositioning for posterior spinal fusion after lateral interbody fusion

Research paper thumbnail of CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 29, 2015

Traditional open exposure for posterior instrumentation requires significant soft tissue mobiliza... more Traditional open exposure for posterior instrumentation requires significant soft tissue mobilization and causes significant blood loss and increased recovery time. Mal-placed screws can injure nerve roots, the spinal cord, viscera, vasculature and the cardiopulmonary system. Placement of pedicle screws using a minimally invasive technique can decrease bleeding risk, damage to soft tissues, and post-operative pain. The purpose of this study is to compare the radiographic accuracy of open free-hand versus percutaneous technique for pedicle screw placement. Consecutive patients undergoing thoracolumbar surgery from September 2006 to October 2011 with post-operative CT imaging were included in this study. Three-dimensional screw positioning within the pedicle and the vertebral body was assessed on CT. The magnitude and location of violations were measured and recorded. Facet breaches at the cephalad and caudad ends of the construct were documented and graded. Two-hundred and twenty-thr...

Research paper thumbnail of C5 palsy after cervical laminectomy and fusion: does width of laminectomy matter?

The spine journal : official journal of the North American Spine Society, Jan 21, 2015

A common complication of cervical laminectomy and fusion with instrumentation (CLFI) is developme... more A common complication of cervical laminectomy and fusion with instrumentation (CLFI) is development of post-operative C5 nerve palsy. A proposed etiology is excess nerve tension from posterior drift of the spinal cord after decompression. We hypothesize that laminectomy width will be significantly increased in patients with C5 palsy and will correlate with palsy severity. To evaluate laminectomy width as a risk factor for C5 palsy and to assess correlation with palsy severity. /Setting: This is a retrospective, single-institution clinical study. Patient population included all patients with cervical spondylotic myelopathy (CSM) who underwent CLFI between 2007 and 2014 by a single surgeon. Patients who underwent CLFI for trauma, infection, or tumor or had previous or circumferential cervical surgery were excluded. All patients with a new C5 palsy received a postoperative MRI. An additional CT scan was ordered to assess hardware. All control patients received a CT scan at 6 months pos...

Research paper thumbnail of Extreme lateral interbody fusion with posterior instrumentation for spondylodiscitis

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, Jan 29, 2015

The purpose of this study was to evaluate our initial experience utilizing extreme lateral interb... more The purpose of this study was to evaluate our initial experience utilizing extreme lateral interbody fusion (XLIF; NuVasive, San Diego, CA, USA) with percutaneous posterior instrumentation to treat 11 spondylodiscitis patients between January 2011 and February 2014. Although medical management is the first line treatment for spondylodiscitis, many patients fail antibiotic therapy and bracing, or present with instability, neurologic deficits, or sepsis, requiring operative debridement and stabilization. High rates of fusion and infection clearance have been reported with anterior lumbar interbody fusion (ALIF), but this approach requires a morbid exposure, associated with non-trivial rates of vascular and peritoneal complications. XLIF is an increasingly popular interbody fusion technique which utilizes a fast and minimally invasive approach, sparing the anterior longitudinal ligament, and allowing sufficient visualization of the intervertebral discs and bodies to debride and place a...

Research paper thumbnail of Time Spent in Lateral Sleep Position and Asymmetry in Glaucoma

Investigative Opthalmology & Visual Science, 2015

To explore sleep position in asymmetric primary open-angle glaucoma (POAG) with a focus on low pr... more To explore sleep position in asymmetric primary open-angle glaucoma (POAG) with a focus on low pressure glaucoma (LPG). Sleep laboratory videos of 54 POAG patients were examined for lateral sleep. Then, 29 LPG patients (intraocular pressure [IOP] < 22 mm Hg) with an intereye visual field index (VFI) asymmetry of more than 5% continuously recorded their sleep position at home for 2 nights by using a portable device. Correlations were sought between sleep position, visual field (VF), and retinal nerve fiber layer (RNFL) symmetry as well as ocular biometric data and positional IOP changes. Finally, an expanded data set of 178 POAG patients (63 LPG and 115 high pressure glaucoma [HPG; IOP ≥ 22 mm Hg]) was used to correlate VF and the RNFL symmetry to the self-assessed sleep position collected in a survey. In the video analysis, patients spent 19% ± 2% (mean ± SEM) more time sleeping on one side than on the other. Right-sided sleep was preferred. Right-sided sleep was 1.6 times more common in continuously recorded home data and correlated to an asymmetric VF that was worse in the left eye (b = -0.422, P = 0.002). Pulse amplitude of left eyes was lower in the right decubitus position (P = 0.02). In the expanded survey, 73% of LPG and 58% of HPG patients slept asymmetrically. Right-sided sleepers had a worse RNFL symmetry score. Asymmetric sleep behavior is common. Right-sided sleep was preferred and correlated with a lower VFI on the left.

Research paper thumbnail of Current Trends in the Management of Lumbar Spine Injuries in Athletes

The Duke Orthopaedic Journal, 2015

Lumbar spine injuries are prevalent among athletes and are likely to increase with the rising pop... more Lumbar spine injuries are prevalent among athletes and are likely to increase with the rising popularity of extreme sports. It is important for physicians to understand the basic anatomy of the lumbar spine along with the injury patterns that can occur with axial loading, hyperflexion and flexion-distraction forces. The majority of low back injuries in athletes are due to muscle strains and rarely need further treatment. Athletes that are sub jected to repetitive hyperextension forces are at risk for spondylolysis with or without spondylolisthesis which requires further imaging to determine need for surgical intervention. Lumbar disk herniations are usually from axial forces and can be result in surgical emergencies, if they cause compression on the spinal cord or conus. Lumbar spine fractures can vary from stress fractures of the endplates to burst fractures or fracturedislocations which require surgical intervention, if associated with neurologic deficit or instability. Similar to the management of cervical spine injuries, patients with a suspected lumbar injury should be evaluated systematically with full spine precautions and careful neurologic examination to determine need for transfer to higher care center.

Research paper thumbnail of Failed Back Surgery Syndrome and Back Pain Patients: Medications They use and How They relate to Their Emotional and Physical Functioning

The Duke Orthopaedic Journal, 2015

Objective: To test the hypothesis that failed back surgery syn drome (FBSS) patients and nonsurgi... more Objective: To test the hypothesis that failed back surgery syn drome (FBSS) patients and nonsurgical back pain (NSBP) patients respond differently on psychological measures and differ in pain medication usage.

Research paper thumbnail of Routine Anteroposterior Radiographs Have Limited Utility for Patients After Anterior Cervical Decompression and Fusion

Spine, Oct 15, 2012

A retrospective case series. To assess the diagnostic utility of sequential anteroposterior (AP) ... more A retrospective case series. To assess the diagnostic utility of sequential anteroposterior (AP) radiographs for following patients with postoperative anterior cervical decompression and fusion (ACDF). There are currently no widely accepted standards for radiographical follow-up after ACDF. Many spine surgeons routinely obtain at least AP and lateral films at serial follow-up visits. It is generally accepted that lateral films are of utility to assess overall alignment, evaluate union, and detect any potential construct-related issues. It is our perception that the AP view adds little or no clinical value after documentation of alignment on an initial film. All follow-up imaging series were evaluated for 100 patients who underwent ACDF. Variables thought to be potentially detected on the AP film were evaluated on both the AP and lateral films (visualization of the implant and instrumented vertebral bodies and any construct-related issues). In addition, angulation of the implant relative to the vertebral axis of the instrumented levels was measured on the AP film. For the 100 patients evaluated, the follow-up period was 1.2 ± 0.5 months (mean ± SD), with 4.39 ± 1.52 imaging series obtained per patient. Instrumented vertebral bodies were fully visualized in 99.5% of AP and 86.7% of lateral films obtained at follow-up visits. The entire implant was visualized in 100% of AP films and 95.6% of lateral films. No hardware-related issues were seen (screw disengagement, pullout, breakage, etc.). No patients were found to have progression of coronal plate angulation beyond 3° at their last follow-up series relative to the first follow-up visit. Using rigorous evaluation methods, we found no significant incremental utility of AP films obtained in addition to lateral films. Therefore, given the inherent cost, time, and radiation exposure associated with each additional view, we propose that AP films should not be part of routine follow-up imaging after ACDF.

Research paper thumbnail of Cervical myelopathy doubles the rate of dislocation and fracture after total hip arthroplasty

The Journal of Arthroplasty, 2016

Cervical spondylotic myelopathy (CSM) is a common and underdiagnosed cause of gait dysfunction, r... more Cervical spondylotic myelopathy (CSM) is a common and underdiagnosed cause of gait dysfunction, rigidity, and falls in the elderly. Given the frequent concurrency of CSM and hip osteoarthritis, this study is designed to evaluate the relative risk of CSM on perioperative and short-term outcomes after total hip arthroplasty (THA). The Medicare Standard Analytical Files were searched from 2005 to 2012 to identify all patients undergoing primary THA and the subset of patients with preexisting CSM. Risk ratios with 95% confidence intervals were calculated for 90-day, 1-year, and overall follow-up for common postoperative complications: periprosthetic dislocation, fracture, infection, revision THA, and wound complications. The risk ratios of all surgical complications, including dislocation, periprosthetic fractures, and prosthetic joint infection, were increased approximately 2-fold at all postoperative time points for patients. Preexisting CSM is a significant risk factor for primary THA complications including dislocation, periprosthetic fractures, and prosthetic joint infection.

Research paper thumbnail of Renal artery injury during lateral transpsoas interbody fusion: case report

Journal of neurosurgery. Spine, Jan 20, 2016

Lateral interbody fusion (LIF) via the retroperitoneal transpsoas approach is an increasingly pop... more Lateral interbody fusion (LIF) via the retroperitoneal transpsoas approach is an increasingly popular, minimally invasive technique for interbody fusion in the thoracolumbar spine that avoids many of the complications of traditional anterior and transforaminal approaches. Renal vascular injury has been cited as a potential risk in LIF, but little has been documented in the literature regarding the etiology of this injury. The authors discuss a case of an intraoperative complication of renal artery injury during LIF. A 42-year-old woman underwent staged T12-L5 LIF in the left lateral decubitus position, and L5-S1 anterior lumbar interbody fusion, followed 3 days later by T12-S1 posterior instrumentation for idiopathic scoliosis with radiculopathy refractory to conservative management. After placement of the T12-L1 cage, the retractor was released and significant bleeding was encountered during its removal. Immediate consultation with the vascular team was obtained, and hemostasis was...

Research paper thumbnail of Should we think twice about psychiatric disease in total hip arthroplasty?

The Journal of Arthroplasty, 2016

Psychiatric disease (PD) is common, and the effect on complications in total hip arthroplasty (TH... more Psychiatric disease (PD) is common, and the effect on complications in total hip arthroplasty (THA) is poorly understood. The purpose of this study was to evaluate the medical and surgical postoperative complication profile in patients with PD, and we hypothesize that they will be significantly increased compared with control group. A search of the entire Medicare database from 2005 to 2011 was performed using International Classification of Disease version 9 codes to identify 86,976 patients who underwent primary THA with PD including bipolar (5626), depression (82,557), and schizophrenia (3776). A cohort of 590,689 served as a control with minimum 2-year follow-up. Medical and surgical complications at 30-day, 90-day, and overall time points were compared between the 2 cohorts. Patients with PD were more likely to be younger (age < 65 years; odds ratio [OR] = 4.51, P < .001), female (OR = 2.02, P < .001) and more medically complex (significant increase in 28/28 Elixhauser medical comorbidities, P < .001). There was a significant increase (P < .001) in 13/14 (92.8%) recorded postoperative medical complications rates at the 90-day time point. In addition, there was a statistically significant increase in periprosthetic infection (OR = 2.26, P < .001), periprosthetic fracture (OR = 2.09, P < .001), dislocation (OR = 2.30, P < .001), and THA revision (OR = 1.93, P < .001) at overall follow-up. Patients with PD who undergo elective primary THA have significantly increased medical and surgical complication rates in the global period and short-term follow-up, and these patients need to be counseled accordingly.

Research paper thumbnail of The Impact of Lumbar Spine Disease and Deformity on Total Hip Arthroplasty Outcomes

Orthopedic Clinics of North America, 2016

Concurrent spine and hip disease is common. Spinal deformities can restrict lumbar range of motio... more Concurrent spine and hip disease is common. Spinal deformities can restrict lumbar range of motion and lumbar lordosis, leading to pelvic obliquity and increased pelvic tilt. A comprehensive preoperative workup and component templating ensure appropriate compensation for altered pelvic parameters for implantation of components according to functional positioning. Pelvic obliquity from scoliosis must be measured to calculate appropriate leg length. Cup positioning should be templated on standing radiograph to limit impingement from cup malposition. In spinal deformity, the optimal position of the cup that accommodates pelvic parameters and limits impingement may lie outside the classic parameters of the safe zone.

Research paper thumbnail of Erratum to: CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European Spine Journal, 2015

Research paper thumbnail of Lumbar Spine Disease Negatively Affects Outcomes after Total Hip Arthroplasty

Research paper thumbnail of The role of iatrogenic foraminal stenosis from lordotic correction in the development of C5 palsy after posterior laminectomy and fusion

Journal of orthopaedic surgery and research, 2015

Post-operative C5 nerve root palsy is a known complication following cervical spine surgery. Alth... more Post-operative C5 nerve root palsy is a known complication following cervical spine surgery. Although several theories have been proposed, there remains no consensus as to the etiology of the palsies. Multiple pre-operative radiographic measures have been assessed for utility in predicting palsy. The purpose of this study is to evaluate published radiographic parameters as well as specifically evaluate the effect of cervical lordosis in the development of C5 palsy to establish thresholds that reliably predict the incidence. This study is a retrospective review of 54 consecutive multilevel cervical laminectomy and fusion surgeries performed by a single spine surgeon between June 2007 and February 2014. Pre-operative MRI and pre- and post-operative plain films were assessed to measure anteroposterior diameter (APD) of the spinal cord, cervical laminar angles, anteroposterior foraminal diameters (FD), cervical curvature index (Ishihara), cervical spine angle (C2-7), and C4-5 angle. Uni...

Research paper thumbnail of Erratum to: CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 12, 2015

Research paper thumbnail of C5 Nerve Palsy in Posterior Cervical Spinal Surgery: Does Width of Laminectomy Matter?

Research paper thumbnail of Is a wider cervical laminectomy a risk factor for postoperative C5 nerve palsy?

Research paper thumbnail of Radiographic Predictors of C5 Palsy Following Multilevel Cervical Laminectomy and Fusion

Research paper thumbnail of Sagital balance and lordosis correction in lateral interbody fusion

Research paper thumbnail of Interval effect of prone repositioning for posterior spinal fusion after lateral interbody fusion

Research paper thumbnail of CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 29, 2015

Traditional open exposure for posterior instrumentation requires significant soft tissue mobiliza... more Traditional open exposure for posterior instrumentation requires significant soft tissue mobilization and causes significant blood loss and increased recovery time. Mal-placed screws can injure nerve roots, the spinal cord, viscera, vasculature and the cardiopulmonary system. Placement of pedicle screws using a minimally invasive technique can decrease bleeding risk, damage to soft tissues, and post-operative pain. The purpose of this study is to compare the radiographic accuracy of open free-hand versus percutaneous technique for pedicle screw placement. Consecutive patients undergoing thoracolumbar surgery from September 2006 to October 2011 with post-operative CT imaging were included in this study. Three-dimensional screw positioning within the pedicle and the vertebral body was assessed on CT. The magnitude and location of violations were measured and recorded. Facet breaches at the cephalad and caudad ends of the construct were documented and graded. Two-hundred and twenty-thr...

Research paper thumbnail of C5 palsy after cervical laminectomy and fusion: does width of laminectomy matter?

The spine journal : official journal of the North American Spine Society, Jan 21, 2015

A common complication of cervical laminectomy and fusion with instrumentation (CLFI) is developme... more A common complication of cervical laminectomy and fusion with instrumentation (CLFI) is development of post-operative C5 nerve palsy. A proposed etiology is excess nerve tension from posterior drift of the spinal cord after decompression. We hypothesize that laminectomy width will be significantly increased in patients with C5 palsy and will correlate with palsy severity. To evaluate laminectomy width as a risk factor for C5 palsy and to assess correlation with palsy severity. /Setting: This is a retrospective, single-institution clinical study. Patient population included all patients with cervical spondylotic myelopathy (CSM) who underwent CLFI between 2007 and 2014 by a single surgeon. Patients who underwent CLFI for trauma, infection, or tumor or had previous or circumferential cervical surgery were excluded. All patients with a new C5 palsy received a postoperative MRI. An additional CT scan was ordered to assess hardware. All control patients received a CT scan at 6 months pos...

Research paper thumbnail of Extreme lateral interbody fusion with posterior instrumentation for spondylodiscitis

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, Jan 29, 2015

The purpose of this study was to evaluate our initial experience utilizing extreme lateral interb... more The purpose of this study was to evaluate our initial experience utilizing extreme lateral interbody fusion (XLIF; NuVasive, San Diego, CA, USA) with percutaneous posterior instrumentation to treat 11 spondylodiscitis patients between January 2011 and February 2014. Although medical management is the first line treatment for spondylodiscitis, many patients fail antibiotic therapy and bracing, or present with instability, neurologic deficits, or sepsis, requiring operative debridement and stabilization. High rates of fusion and infection clearance have been reported with anterior lumbar interbody fusion (ALIF), but this approach requires a morbid exposure, associated with non-trivial rates of vascular and peritoneal complications. XLIF is an increasingly popular interbody fusion technique which utilizes a fast and minimally invasive approach, sparing the anterior longitudinal ligament, and allowing sufficient visualization of the intervertebral discs and bodies to debride and place a...

Research paper thumbnail of Time Spent in Lateral Sleep Position and Asymmetry in Glaucoma

Investigative Opthalmology & Visual Science, 2015

To explore sleep position in asymmetric primary open-angle glaucoma (POAG) with a focus on low pr... more To explore sleep position in asymmetric primary open-angle glaucoma (POAG) with a focus on low pressure glaucoma (LPG). Sleep laboratory videos of 54 POAG patients were examined for lateral sleep. Then, 29 LPG patients (intraocular pressure [IOP] < 22 mm Hg) with an intereye visual field index (VFI) asymmetry of more than 5% continuously recorded their sleep position at home for 2 nights by using a portable device. Correlations were sought between sleep position, visual field (VF), and retinal nerve fiber layer (RNFL) symmetry as well as ocular biometric data and positional IOP changes. Finally, an expanded data set of 178 POAG patients (63 LPG and 115 high pressure glaucoma [HPG; IOP ≥ 22 mm Hg]) was used to correlate VF and the RNFL symmetry to the self-assessed sleep position collected in a survey. In the video analysis, patients spent 19% ± 2% (mean ± SEM) more time sleeping on one side than on the other. Right-sided sleep was preferred. Right-sided sleep was 1.6 times more common in continuously recorded home data and correlated to an asymmetric VF that was worse in the left eye (b = -0.422, P = 0.002). Pulse amplitude of left eyes was lower in the right decubitus position (P = 0.02). In the expanded survey, 73% of LPG and 58% of HPG patients slept asymmetrically. Right-sided sleepers had a worse RNFL symmetry score. Asymmetric sleep behavior is common. Right-sided sleep was preferred and correlated with a lower VFI on the left.

Research paper thumbnail of Current Trends in the Management of Lumbar Spine Injuries in Athletes

The Duke Orthopaedic Journal, 2015

Lumbar spine injuries are prevalent among athletes and are likely to increase with the rising pop... more Lumbar spine injuries are prevalent among athletes and are likely to increase with the rising popularity of extreme sports. It is important for physicians to understand the basic anatomy of the lumbar spine along with the injury patterns that can occur with axial loading, hyperflexion and flexion-distraction forces. The majority of low back injuries in athletes are due to muscle strains and rarely need further treatment. Athletes that are sub jected to repetitive hyperextension forces are at risk for spondylolysis with or without spondylolisthesis which requires further imaging to determine need for surgical intervention. Lumbar disk herniations are usually from axial forces and can be result in surgical emergencies, if they cause compression on the spinal cord or conus. Lumbar spine fractures can vary from stress fractures of the endplates to burst fractures or fracturedislocations which require surgical intervention, if associated with neurologic deficit or instability. Similar to the management of cervical spine injuries, patients with a suspected lumbar injury should be evaluated systematically with full spine precautions and careful neurologic examination to determine need for transfer to higher care center.

Research paper thumbnail of Failed Back Surgery Syndrome and Back Pain Patients: Medications They use and How They relate to Their Emotional and Physical Functioning

The Duke Orthopaedic Journal, 2015

Objective: To test the hypothesis that failed back surgery syn drome (FBSS) patients and nonsurgi... more Objective: To test the hypothesis that failed back surgery syn drome (FBSS) patients and nonsurgical back pain (NSBP) patients respond differently on psychological measures and differ in pain medication usage.