Cameron Schmidt

Meningocele manqué: a comprehensive review of this enigmatic finding in occult spinal dysraphism

The term meningocele manqué (MM) was coined in 1972 to describe a broad range of surgical findings characterized by intradural bands tethering neural structures to the dorsal dura. Over the following decades, reports continued to lump intradural tethering bands associated with a variety of comorbidities under the umbrella term MM. In more recent years, disorders previously called MM have been identified as embryologically distinct and were reclassified. While this sectioning continues, there remains a set of intradural tethering disorders for which no better term than MM exists. Herein, we comprehensively review the literature surrounding MM, including embryological disorders, clinical, radiographic, and surgical presentation, as well as alternative classification methods and MM treatment.

Junctional neural tube defect in a newborn: report of a fourth case

IntroductionA discontinuous, functionally disconnected spinal cord is an extremely rare finding, with only three known reports in the literature. Titled junctional neural tube defect (JNTD), this newly reported dysraphism is believed to arise from a developmental error occurring during junctional neurulation, a transitory stage of development marked by the end of primary neurulation and the beginning of secondary neurulation. Herein, we report a newborn case of JNTD.Case reportWe report a newborn boy born with anorectal atresia. Physical examination revealed normal movement in the upper and lower extremities. Imaging revealed distal sacral agenesis and a spinal cord that was discontinuous at the thoracolumbar junction. Three vertebral segments inferiorly, at the L2 vertebral level, the distal end of the spinal cord (i.e., conus medullaris) were visualized. No signs of a tethered cord were identified.ConclusionsCharacterized by an error in junctional neurulation in which the primary and secondary NT fail to integrate appropriately, JNTD has been recently classified. We believe the current patient to represent only the fourth reported case of JNTD in the literature.

Neuroanatomy of Anxiety: A Brief Review

Anxiety disorders are among the most prevalent psychological issues worldwide, displaying the youngest age of onset and greatest chronicity of any mood or substance abuse disorder. Given the high social and economic cost imposed by these disorders, developing effective treatments is of the utmost importance. Anxiety disorders manifest in a variety of symptomatic phenotypes and are highly comorbid with other psychological diseases such as depression. These facts have made unraveling the complex underlying neural circuity an ever-present challenge for researchers. We offer a brief review on the neuroanatomy of anxiety disorders and discuss several currently available therapeutic options.

Adult Apical Ligament of the Dens Lacks Notochordal Tissue: Application to Better Understanding the Origins of Skull Base Chordomas

INTRODUCTION The apical ligament has long been reported to contain notochord remnants and thus might serve as a site of origin of chordoma formation at the skull base. However, to our knowledge, the histologic study of the apical ligament using histologic staining specific for notochordal tissue has not been previously performed. Therefore the current study was undertaken. METHODS Fifteen apical ligament samples underwent histologic examination with specific markers for notochordal differentiation. RESULTS Across all samples, there was no indication of any notochordal remnants. CONCLUSIONS On the basis of our cadaveric study, the apical ligament does not contain notochord tissue and in adults should not be considered a remnant of this structure. Moreover, it is unlikely that the apical ligament gives rise to chordomas at the craniocervical junction under normal circumstances.

Injury to the Lumbar Plexus and its Branches After Lateral Fusion Procedures: A Cadaver Study

INTRODUCTION Neurologic deficits from lumbar plexus nerve injuries commonly occur in patients undergoing lateral approaches. However, it is not yet clear what types of injury occur, where anatomically they are located, or what mechanism causes them. We aimed to study 1) the topographic anatomy of lumbar plexus nerves and their injuries in human cadavers after lateral transpsoas approaches to the lumbar spine, 2) the structural morphology of those injuries, and 3) the topographic anatomy of the lumbar plexus throughout the mediolateral approach corridor. METHODS Fifteen adult fresh frozen cadaveric torsos (26 sides) underwent lateral approaches (L1-L5) by experienced lateral spine surgeons. The cadavers were subsequently opened and the entire plexus dissected and examined for nerve injuries. The topographic anatomy of the lumbar plexus and its branches, their injuries, and the morphology of these injuries were documented. RESULTS Fifteen injuries were found with complete or partial nerve transections (Sunderland IV and V). Injuries were found throughout the mediolateral approach corridor. At L1/2, the iliohypogastric, ilioinguinal, and subcostal nerves were injured within the psoas major muscle, the retroperitoneal space, or the outer abdominal muscles and subcutaneous tissues. Genitofemoral nerve injuries were found in the retroperitoneal space. Nerve root injuries occurred within the retroperitoneal space and psoas muscle. Femoral nerve injuries were found only within the psoas major muscle. No obturator nerve injuries occurred. CONCLUSIONS Lateral approaches can lead to structural nerve damage. Knowledge of the complex plexus anatomy, specifically its mediolateral course, is critical to avoid approach-related injuries.

Failure Patterns in Standalone Anterior Cervical Discectomy and Fusion Implants

BACKGROUND Anterior cervical discectomy and fusion is commonly performed using an allograft or autograft implant and anterior screw-supported plate. There has been an increase in the use of standalone cage devices due to ease of use and studies suggesting a lower rate of acute postoperative dysphagia. We review our experience with standalone cage devices and identify risk factors, patterns of failure, and revision surgery approaches. METHODS We performed a retrospective case series of patients treated at a single tertiary care institution between March 2014 and March 2015. Inclusion criteria were aged 18-100 years, 1- or 2-level anterior cervical discectomy and fusion with a standalone cervical cage. Data collected included demographics, comorbidities, Charlson comorbidity score, primary diagnosis, and surgical characteristics. Descriptive statistics were performed for risk of readmission, implant failure, revision, and other complications. RESULTS We identified 211 patients who met our study criteria. Average surgical time was 107 ± 43 minutes, with an estimated blood loss of 84.6 ± 32.4 mL. There were 11 (5.2%) readmissions. There were 10 (4.74%) implant failures (5 involving single-level surgery and 5 involving 2-level surgery), with 7 cases of pseudoarthrosis. Mechanisms of failure included a C5 body fracture, fusion in a kyphotic alignment after graft subsidence, and acute spondylolisthesis. CONCLUSIONS Revision surgery after standalone anterior cervical implants can be complex. Posterior cervical fusion remains a valuable approach to avoid possible vertebral body fracture and loss of fusion area associated with the removal of implants secured through the endplates of adjacent vertebral bodies.

Anatomical Study and Comprehensive Review of the Incisivus Labii Superioris Muscle: Application to Lip and Cosmetic Surgery

Objectives The incisivus labii superioris muscle, which originates from the floor of the incisive fossa of the maxilla, has previously been described, it is not well understood. The purpose of this study was to investigate the incisivus labii superioris muscle with detailed dissection. Methods Twenty-six halves from thirteen fresh frozen cadaveric Caucasian heads were used in this study. First, the incisivus labii superioris muscle was dissected to reveal its origin and insertion, and its relationship to other mimetic muscles. Secondly, the distance from the midline to the innermost part of the bony attachment of the muscle was measured. The literature describing the incisivus labii superioris muscle was reviewed. Results The incisivus labii superioris muscle consisted of two parts, inferior and superior. The former merged into the orbicularis oris and the latter into the nasalis. The mean distance from the midline to the innermost part of the bony attachment of the incisivus labii superioris muscle was 4.8 ± 1.7 mm on the right side and 4.9 ±1.7 mm on the left. Conclusions The results of the present study suggest that the inferior part of the incisivus labii superioris should be considered as an accessory muscle of the orbicularis oris complex, and the superior part is the nasalis muscle.

A comprehensive review of the anterior fontanelle: embryology, anatomy, and clinical considerations

PurposeFontanelles are a regular feature of infant development in which two segments of bone remain separated, leaving an area of fibrous membrane or a “soft spot” that acts to accommodate growth of the brain without compression by the skull. Of the six fontanelles in the human skull, the anterior fontanelle, located between the frontal and parietal bones, serves as an important anatomical diagnostic tool in the assessment of impairments of the skull and brain and allows access to the brain and ventricles in the infant.MethodsUsing a standard database search, we conducted a review of the anterior fontanelle, including its embryology, anatomy, pathology, and related surgical implications.ConclusionsThe diagnostic value of the anterior fontanelle, through observation of its shape, size, and palpability, makes the area of significant clinical value. It is important that clinicians are aware of the features and associated pathologies of this area in their everyday practice.

Functional Neurorehabilitation using the Hybrid Assistive Limb (HAL): A First Experience in the United States

Introduction: The Hybrid Assistive Limb (HAL, Cyberdyne, Japan) facilitates voluntary, user-driven ambulation through a neurologically-controlled system based on bioelectrical signals derived from the user. This allows for the repeated execution of physiologically faithful gait patterns, crucial to recovery in cases of neurologic motor deficit. In this series, we present the first three patients in the United States to undergo HAL neurorehabilitation training. Patient and methods: A case series of three patients participating in a single-center prospective, interventional pilot study, suffering neurologic motor deficits secondary to spinal cord infarct following a pulmonary embolism (patient 1), multiple sclerosis (patient 2) and the surgical resection of a petroclival meningioma (patient 3). The patients underwent 60 sessions of body weight-supported treadmill training in the HAL over the course of 12 weeks. Measures of functional ambulation (10 Minute Walk Test, 10MWT) were performed out of the HAL before and after each session and at the 12 week and 6 month follow-up. Timed Up & Go (TUG) test was performed each week. Treadmill data (time, distance) while in HAL was recorded at each session. Measures of endurance (6 Minute Walk Test, 6MWT), risk of fall (TUG), balance impairment (Berg Balance Scale) and improvements in walking performance (Walking Index for Spinal Cord Injury II, WISCI II) were measured at baseline, after 12 weeks and at 6 months follow-up. Results: Patients 2 and 3 completed 60 visits, patient 1 completed 56 visits. All patients achieved markedly increased treadmill paces, improved functional scores, increased distance in the 6MWT and decreased TUG times at 6-month follow-up. In the 10MWT, all patients achieved a clinically significant decrease in time and steps and showed improvements in the required assistance level to perform the test. Patients 1 and 3 showed improvement on the Berg Balance Scale. Patient 2 had no change between baseline and 6-month follow-up. Only minor adverse effects were reported, including skin abrasions and irritation secondary to chaffing of the HAL unit and EMG electrodes. Conclusion: These data show that HAL training is both feasible and effective in the neurorehabilitation of patients suffering neurologic motor deficits secondary to trauma and/or pathological/neurodegenerative processes after they have undergone normal rehab. A greater number of patients are required to meaningfully assess the differences in improvement from baseline, based upon underlying pathologies.

The Alar Ligaments: A Cadaveric and Radiologic Comparison Study

OBJECTIVE A precise anatomical description of the alar ligaments is important to better understand their biomechanical and pathologic implications. Although there are several studies regarding their anatomy, the literature is inconsistent. To our knowledge, there are no reports that compare cadaveric morphologic findings with computed tomography (CT) images of the alar ligaments. METHODS Eight sides from 4 fresh-frozen cadaveric specimens were used in this study. After routine dissection of the craniocervical junction, the alar ligaments were exposed. We carried out measurements of the alar ligaments, their position within the craniovertebral junction, and their relation to the dens and adjacent structures. Fine-cut CT of the specimens was performed, and the measurements were later compared with the original cadaveric dissections. RESULTS Alar ligaments were attached to the upper half of the lateral surface of the dens and ran laterally to its insertion just medial to the occipital condyle. The ligaments were found to have an ovoid cross-sectional area with a nearly horizontal caudocranial trajectory and comparable diameters in both anteroposterior and superoinferior directions between the CT and cadaveric measurements. CONCLUSIONS There were small but not statistically significant differences in the measurements between the cadaver specimens and the CT images. There was however, a strong correlation between the proximal and distal insertions, as well as the orientation of the fibers, that suggests CT images can be an appropriate approach to the study of the anatomical and 3-dimensional features of the alar ligaments.