Rod Attachment Induces Significant Strain in Lumbosacral Fixation.

Study Design: This was a laboratory investigation.

Objective: Rod attachment can induce significant pedicle screw-and-rod pre- strain that may predispose the instrumentation to failure. This study investigated how in vitro L5-S1 rod strain and S1 screw strain during rod-screw attachment (pre-strain) compared with strains recorded during pure-moment bending ( test- strain).

Pedicle Subtraction Osteotomy Construct Optimization: A Cadaveric Study of Various Multirod and Interbody Configurations.

Study Design: Fourteen cadaveric specimens were separated into two groups: (1) L3 pedicle subtraction osteotomy (PSO) with transforaminal lumbar interbody fusion (TLIF) or (2) lateral lumbar interbody fusion (LLIF). A 2-rod configuration (2R) was compared with two supplemental rod configurations: 4-rod (4R) with accessory rods (ARs) using connectors or 4R with satellite rods (SRs) without connectors.

Objective: Compare PSO constructs with different rod configurations and adjacent-level interbody support.

Novel Distributed Loading Technique Using Multimaterial, Long-Segment Spinal Constructs to Prevent Proximal Junctional Pathology in Adult Spinal Deformity Correction-Operative Technique and Radiographic Findings.

Background: Proximal junctional kyphosis (PJK) and proximal junction failure are common and costly complications after long-segment adult spinal deformity (ASD) correction. Although much research has focused on the concept of "softening the landing" to prevent proximal junction pathologies, long-segment constructs largely deviate from the force-deformation curve of the physiologic spine. Our novel distributed loading technique for ASD correction is described using multimaterial, long-segment constructs to create a biomechanically sound, yet physiologic, decremental stiffness toward the rostral end.

Accuracy of Subaxial Cervical Pedicle Screw Placement Using Direct Visualization Versus Computed Tomography-Based Navigation.

Study Design: Retrospective analysis of operative data from cadaveric cervical spines.

Objective: To evaluate the accuracy of neuronavigation compared with laminotomy with direct visualization (DV) of the pedicle for placement of subaxial pedicle screws.

Summary Of Background Data: Subaxial pedicle screws provide superior fixation compared with other posterior cervical fixation strategies.

Biomechanics of open versus minimally invasive deformity correction:​ comparison of stability and rod strain between pedicle subtraction osteotomy and anterior column realignment.

Objective: Anterior column realignment (ACR) is a new minimally invasive approach for deformity correction that achieves a degree of lordosis similar to that obtained with pedicle subtraction osteotomy (PSO). This study compared the biomechanical profiles of ACR with PSO using range of motion (ROM) and posterior rod strain (RS) to gain insight into the ACR technique and the necessary surgical strategies to optimize longevity and stability.

Methods: An in vitro biomechanical study using standard flexibility testing (7.

Impact of dual-headed pedicle screws on the biomechanics of lumbosacral junction multirod constructs.

Objective: The objective of this study was to evaluate a novel connector design and compare it with traditional side connectors, such as a fixed-angle connector (FAC) and a variable-angle connector (VAC), with respect to lumbosacral stability and instrumentation strain.

Methods: Standard nondestructive flexibility tests (7.5 Nm) and compression tests (400 N) were performed using 7 human cadaveric specimens (L1-ilium) to compare range of motion (ROM) stability, posterior rod strain (RS), and sacral screw bending moment (SM).

Functional improvement in hand strength and dexterity after surgical treatment of cervical spondylotic myelopathy: a prospective quantitative study.

Objective: Cervical spondylotic myelopathy (CSM) is the primary cause of adult spinal cord dysfunction. Diminished hand strength and reduced dexterity associated with CSM contribute to disability. Here, the authors investigated the impact of CSM severity on hand function using quantitative testing and evaluated the response to surgical intervention.

Release of Anterior Longitudinal Ligament in Setting of Unfavorable Vascular Anatomy for Anterior Column Realignment-Technical Note: 2-Dimensional Operative Video.

Anterior column realignment (ACR) with anterior longitudinal ligament (ALL) release from a lateral transpsoas approach is increasingly being used as a minimally invasive technique to restore lordosis. Safe execution requires a plane between the ALL and the anterior vasculature. An unfavorable plane on preoperative imaging is a contraindication to using the technique.

Optimizing biomechanics of anterior column realignment for minimally invasive deformity correction.

Background Context: Anterior column realignment (ACR) is a powerful but destabilizing minimally invasive technique for sagittal deformity correction. Optimal biomechanical design of the ACR construct is unknown.

Purpose: Evaluate the effect of ACR design on radiographic lordosis, range of motion (ROM) stability, and rod strain (RS) in a cadaveric model.

The Role of Potentially Modifiable Factors in a Standard Work Protocol to Decrease Complications in Adult Spinal Deformity Surgery: A Systematic Review, Part 1.

Study Design: Structured Literature Review.

Objectives: We sought to evaluate the peer-reviewed literature for potentially modifiable patient and surgical factors that could be incorporated into a Standard Work protocol to decrease complications in adult spinal deformity (ASD) surgery.

Summary Of Background Data: Lean Methodology uses Standard Work to improve efficiency and decrease waste and error.

Styloidogenic Jugular Venous Compression Syndrome: Clinical Features and Case Series.

Background: Styloidogenic jugular venous compression syndrome (SJVCS) is a rare cause of idiopathic intracranial hypertension (IIH).

Objective: To elucidate the pathophysiology and the hemodynamics of SJVCS.

Methods: We conducted a retrospective review of medical records, clinical images, dynamic venography, and manometry for consecutive patients with SJVCS undergoing microsurgical decompression from April 2009 to October 2017.

Far-lateral Vascularized Rib Graft for Cervical and Lumbar Spinal Arthrodesis: Cadaveric Technique Description.

Background: Rotational vascularized autografts are ideal for achieving spinal arthrodesis because they maintain bony vascularization while avoiding the morbidity and challenges of free-tissue transfer. Although proximal ribs are ideal candidates for vascularized bone grafts, their use is restricted to the thoracic spine. This study describes a novel technique for harvesting lateral rib grafts on an intercostal pedicle for use in cervical and lumbar posterolateral arthrodesis.

Selective posterior cerebral artery amobarbital test: a predictor of memory following subtemporal selective amygdalohippocampectomy.

Background: The selective posterior cerebral artery (PCA) amobarbital test, or PCA Wada test, is used to predict memory impairment after epilepsy surgery in patients who have previously had a failed internal carotid artery (ICA) amobarbital test.

Methods: Medical records from 2012 to 2018 were retrospectively reviewed for all patients with seizures who underwent a selective PCA Wada test at our institution following a failed or inconclusive ICA Wada test. Standardized neuropsychological testing was performed before and during the Wada procedure and postoperatively in patients who underwent resection.

Retrospective Multicenter Assessment of Rod Fracture After Anterior Column Realignment in Minimally Invasive Adult Spinal Deformity Correction.

Background: Anterior column realignment (ACR) was developed as a minimally invasive method for treating sagittal imbalance. However, rod fracture (RF) rates associated with ACR are not known. Our objective was to assess the rate of and risk factors for RF following ACR in deformity correction surgery.

Supplemental rods are needed to maximally reduce rod strain across the lumbosacral junction with TLIF but not ALIF in long constructs.

Background Context: Rod fracture at the lumbosacral (LS) junction remains challenging in long segment fusions and likely stems from increased LS strain. Reduction of LS instrumentation strain may help reduce fracture rates.

Purpose: The goal of this investigation was to assess the effect of supplemental posterior 4-rod (4R) construction on LS stability and rod strain compared with standard 2-rod (2R) construction in a long segment fusion model.

Disc Geometry is an Accurate Predictor of Lordotic Correction in the Thoracolumbar Spine Following Schwab Grade 2 Osteotomy: A Cadaveric Study and Biomechanical Analysis of Disc Space Changes Following Lordotic Correction.

Background: Posterior column osteotomy (PCO) is a powerful technique for correcting lordosis, but the surgical literature lacks objective evidence on preoperative predictors of achievable lordotic correction following PCO.

Objective: To measure the correlation between disc geometry and achievable lordotic correction following Schwab grade 2 osteotomies and to describe geometric changes to disc space following lordotic correction.

Methods: Schwab grade 2 osteotomies were performed from T1 to S1 in 5 cadavers.

Posterior open-wedge anterior longitudinal ligament release: Cadaveric technique analysis.

Anterior column release is a powerful surgical technique for achieving spinopelvic balance in adult patients with sagittal plane deformities. We present an alternative strategy for focal deformity correction from a posterior-only approach. The purpose of this study was to evaluate the feasibility and efficacy of a novel surgical technique called posterior open-wedge diskectomy and anterior longitudinal ligament (ALL) release (POWAR).

Iliac screws may not be necessary in long-segment constructs with L5-S1 anterior lumbar interbody fusion: cadaveric study of stability and instrumentation strain.

Background Context: Lumbosacral pseudoarthrosis and instrumentation failure is common with long-segment constructs. Optimizing lumbosacral construct biomechanics may help to reduce failure rates. The influence of iliac screws and interbody type on range of motion (ROM), rod strain (RS), sacral screw strain (SS) is not well-established.

Operative Management of Idiopathic Spinal Cord Herniation: Case Series and Novel Technique for Repair of Recurrent Herniation.

Background: Idiopathic spinal cord herniation (ISCH) is a rare pathology of the spine defined by herniation of the spinal cord through a dural defect.

Objective: To highlight the operative management of ISCH and the surgical nuances of ISCH repairs conducted at our institution.

Methods: This retrospective review examines consecutive patients with ISCH who were treated surgically between January 1, 2010, and July 31, 2017, at Barrow Neurological Institute, Phoenix, Arizona.

Transpsoas Approach Nuances.

The transpsoas approach is a powerful tool in correcting adult spinal deformity secondary to the degenerative process. It may be used as a stand-alone construct or in combination with other approaches to correct both coronal and sagittal malalignment. Preoperative planning with careful analysis of full-length 36-in radiographs and an MRI of the lumbar spine is essential in determining the safety and feasibility of this approach.

Divergent Bilateral Posterior Lumbar Interbody Fusion with Cortical Screw Fixation: Description of New Trajectory for Interbody Technique from Midline Exposure.

Background: A major drawback to use of cortical bone trajectory pedicle screws (CBTPSs) with traditional posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion grafts is that traditional graft insertion trajectories require wider posterior exposure. This wider exposure, beyond the limits otherwise required for CBTPS placement, negates a primary benefit of CBTPS fixation. The aim of this study was to define an alternative surgical technique for interbody graft placement that, when used in conjunction with CBTPS fixation, permits both minimal soft tissue dissection and optimal graft placement.

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for the Treatment of Hypothalamic Hamartomas: A Retrospective Review.

Background: Hypothalamic hamartomas (HH) are rare lesions associated with treatment-resistant epilepsy. Open surgery results in modest seizure control (about 50%) but has a significant associated morbidity. Radiosurgery is limited to a subset of patients due to latent therapeutic effects.

Safety and accuracy of freehand versus navigated C2 pars or pedicle screw placement.

Background Context: C2 pedicle and pars screws require accurate placement to avoid injury to nearby neurovascular structures. Freehand, fluoroscopically guided, and computed tomography (CT)-based navigation techniques have been described in the medical literature.

Purpose: The present study aims to compare the safety and accuracy of the freehand technique versus stereotactic navigation for the placement of C2 pedicle and pars screws.

A novel duraplasty technique following fenestration of a massive lumbar arachnoid cyst in a patient with scoliosis: technical case report.

When a dural defect is encountered during spine surgery, the dura mater must be reconstituted to minimize the occurrence of minor or major life-threatening sequelae. The neurosurgical literature lacks strategies for managing large dural defects encountered during surgery. The authors describe a 24-year-old man who developed cauda equina syndrome secondary to altered CSF flow in a large thoracolumbar arachnoid cyst.

Treatment for Recurrent Lumbar Disc Herniation.

Purpose Of Review: Recurrent lumbar disc herniation (RLDH) is the most common indication for reoperation after a lumbar discectomy. The purpose of this manuscript is to review the incidence, risk factors, and treatment for RLDH.

Recent Findings: Patients who require revision surgery for RLDH improved significantly compared to baseline; however, the magnitude of improvement is less than in primary discectomy patients.