John C. Quinn

Stereotactic brain biopsy with a low-field intraoperative magnetic resonance imager.

BACKGROUND: Techniques for stereotactic brain biopsy have evolved in parallel with the imaging modalities used to visualize the brain. OBJECTIVE: To describe our technique for performing stereotactic brain biopsy using a compact, low-field, intraoperative magnetic resonance imager (iMRI). METHODS: Thirty-three patients underwent stereotactic brain biopsies with the PoleStar N-20 iMRI system (Medtronic Navigation, Louisville, Colorado). Preoperative iMRI scans were obtained for biopsy target identification and trajectory planning. A skull-mounted device (Navigus, Medtronic Navigation) was used to guide an MRI-compatible cannula to the target. An intraoperative image was acquired to confirm accurate cannula placement within the lesion. Serial images were obtained to track cannula movement and to rule out hemorrhage. Frozen sections were obtained in all but 1 patient with a brain abscess. RESULTS: Diagnostic tissue was obtained in 32 of 33 patients. In all cases, imaging demonstrated cannula placement within the lesion. Histological diagnoses included 22 primary brain tumors and 10 nonneoplastic lesions. In 61% of the cases, initial trajectory was corrected on the basis of the intraoperative scans. In 1 patient, biopsy was nondiagnostic despite accurate cannula placement. No patient suffered a clinically or radiographically significant hemorrhage during or after surgery. There were no intraoperative complications. CONCLUSION: Stereotactic biopsy with a low-field iMRI is an accurate way to obtain specimens with a high diagnostic yield. This accuracy, combined with the acceptable additional procedural time, may obviate the need for frozen section. The ability to correct biopsy cannula placement during surgery eliminates the chance of misdiagnosis because of faulty targeting, as well as the risks associated with inconclusive frozen sections and “blind” replacement of the cannula.

A comparative analysis of minimally invasive and open spine surgery patient education resources

OBJECT The Internet has become a widespread source for disseminating health information to large numbers of people. Such is the case for spine surgery as well. Given the complexity of spinal surgeries, an important point to consider is whether these resources are easily read and understood by most Americans. The average national reading grade level has been estimated to be at about the 7th grade. In the present study the authors strove to assess the readability of open spine surgery resources and minimally invasive spine surgery resources to offer suggestions to help improve the readability of patient resources. METHODS Online patient education resources were downloaded in 2013 from 50 resources representing either traditional open back surgery or minimally invasive spine surgery. Each resource was assessed using 10 scales from Readability Studio Professional Edition version 2012.1. RESULTS Patient education resources representing traditional open back surgery or minimally invasive spine surgery were all found to be written at a level well above the recommended 6th grade level. In general, minimally invasive spine surgery materials were written at a higher grade level. CONCLUSIONS The readability of patient education resources from spine surgery websites exceeds the average reading ability of an American adult. Revisions may be warranted to increase quality and patient comprehension of these resources to effectively reach a greater patient population.

Anterior surgical treatment of cervical spondylotic myelopathy: review article.

BackgroundCervical spondylotic myelopathy (CSM) is a common indication for cervical spine surgery. Surgical options include anterior, posterior, or combined procedures each with specific advantages and disadvantages.Questions/PurposesThis article will provide a description of the various anterior alternatives and discuss the available evidence used in guiding the surgical decision making process with the aim of answering the following questions: (1) What anatomical/disease related factors favor anterior over posterior surgeries? (2) What are the common anterior procedures and how safe and effective are they? (3) What are the most effective options for multilevel CSM? (4) Is there a role for motion preservation? An additional objective is to discuss technical advances that have improved success rates for anterior procedures.MethodsThe PubMed database was searched. Keywords were CSM and anterior surgery. Three hundred eighty two articles were found one hundred three were reviewed. Articles describing anterior cervical techniques were selected along with studies describing the various anterior techniques or comparisons of anterior to posterior techniques.ResultsAnterior decompression and fusion procedures are more effective than posterior procedures for patients with primarily ventrally located compression especially in the presence of cervical kyphosis. ACDF, ACCF, and hybrid combinations are safe and effective treatment options for multilevel CSM. Anterior procedures may be more cost effective and result in significantly improved postoperative quality of life and health-related quality of life measures compared to posterior procedures.ConclusionAnterior cervical decompression techniques are safe and effective in the treatment of CSM. Anterior surgeries may be preferable to posterior approaches, when considering health-related quality of life measures and cost effectiveness.

Magnetic Resonance Neurography of the Lumbar Plexus at the L4-L5 Disc: Development of a Preoperative Surgical Planning Tool for Lateral Lumbar Transpsoas Interbody Fusion (LLIF).

Study Design. Observational study. Objective. To demonstrate use of magnetic resonance (MR) neurography to visualize the course of the lumbar plexus at the L4–L5 disc space. Summary of Background Data. Risk of injury to the lumbar plexus during lateral transpsoas approach for lumbar interbody fusion (LLIF) is significant. We describe a new technique for preoperative mapping using magnetic resonance neurography to directly visualize the course of the plexus relative to the L4–L5 disc space. Methods. Consecutive lumbar plexus MR neurograms (n=35 patients, 70 sides) were studied. Scans were obtained on a Siemens 3-Tesla Skyra magnetic resonance imaging scanner. T1– and T2–color-coded fusion maps were generated along with 3-dimensional models of the lumbosacral plexus with attention to the L4–L5 interspace. The position of the plexus and the shape of the psoas muscle at the L4–L5 interspace were evaluated and recorded. Results. Direct imaging of the lumbar plexus using MR neurography revealed a substantial variability in the position of the lumbar plexus relative to the L4–L5 disc space. The left-side plexus was identified in zone 2 (5.7%), zone 3 (54.3%), and zone 4 (40%) (P = 0.0014); on the right, zone 2 (8.6%), zone 3 (42.9%) or zone 4 (45.7%), and zone 5 (2.9%) (P = 0.01). Right-left symmetry was found in 18 of 35 subjects (51.4%) (P = 0.865). There was no association between the position of the plexus and the shape of the overlying psoas muscle identified. In patients with an elevated psoas (n = 12), the lumbar plexus was identified in zone 3 in 75% and 66% (left and right) compared with patients without psoas elevation (n = 23), 30.4% and 43.5% (left and right). Conclusion. The course of the lumbosacral plexus traversing the L4–L5 disc space may be more variable than has been suggested by previous studies. Magnetic resonance neurography may provide a more reliable means of preoperatively identifying the plexus when compared with current methods. Level of Evidence: 3

Vascular inflammation with eosinophils after the use of n-butyl cyanoacrylate liquid embolic system

Objective and importance Currently, n-butyl cyanoacrylate (n-BCA) is one of the most widely used liquid embolic agents in the treatment of intracranial arteriovenous malformations (AVMs). The cases of three patients are reported who underwent endovascular embolization with n-BCA, followed by resection in two and post-embolization hemorrhage with emergent evacuation in one, with histologic demonstration of an eosinophilic vasculitis found in resected AVM specimens. This is probably the first report of this tissue reaction, which may have theoretically serious clinical implications. Clinical presentation In this series, three patients (2 women, 1 man) presented with intracranial AVMs (Spetzler–Martin I–III) with the lesions located in the frontal lobe in two of the patients and in the parietal lobe in one. All patients presented with headache, and one also had new-onset seizures. Intervention All patients underwent embolization with n-BCA before a planned, staged surgical resection of the embolized AVMs. One patient had four embolizations over a 5-month period, one had three embolizations over 3 months complicated by hemorrhage after embolization requiring emergent evacuation of the hematoma, and the third patient had a single embolization. In all three patients, surgical and autopsy specimens showed an inflammatory response within the embolized vasculature with a prominent eosinophilic infiltrate. Conclusion The eosinophilic vasculitis seen in the pathology specimens may represent a previously undocumented hypersensitivity reaction following exposure to n-BCA, with the potential for adverse sequelae, including increased risk of hemorrhage as was seen in one of our patients.

Posterior Surgical Treatment of Cervical Spondylotic Myelopathy

BackgroundCervical spondylosis is now recognised as the leading cause of myelopathy and spinal cord dysfunction worldwide. Chronic spinal cord compression results in chronic inflammation, cellular apoptosis, and microvacular insufficiency, which are thought to the biologic basis for cervical spondylotic myelopathy (CSM).Questions/PurposesOur purpose was to address the key principles of CSM, including natural history and presentation, pathogenesis, optimal surgical approach, results and complication rates of posterior surgical approaches for CSM so that the rationale for addressing CSM by a posterior approach can be fully understood.MethodsWe conducted a systematic search of PubMed/MEDLINE and the Cochrane Collaboration Library for literature published through February 2014 to identify articles that evaluated CSM and its management. Reasons for exclusion included patients with ossification of the posterior longitudinal ligament (OPLL), patients with degenerative disc disease without CSM, and patients with spine tumor, trauma and infection. Meeting abstracts/proceedings, white articles and editorials were additionally excluded.ResultsThe search strategy yielded 1,292 articles, which was reduced to 52 articles, after our exclusion criteria were introduced. CSM is considered to be a surgical disorder due to its progressive nature. There is currently no consensus in the literature whether multilevel spondylotic compression is best treated via an anterior or posterior surgical approach.ConclusionMultilevel CSM may be safely and effectively treated using a posterior approach, either by laminoplasty or with a laminectomy and fusion technique.

Hybrid lateral mass screw sublaminar wire construct: A salvage technique for posterior cervical fixation in pediatric spine surgery

We present a novel salvage technique for pediatric subaxial cervical spine fusion in which lateral mass screw fixation was not possible due to anatomic constraints. The case presentation details a 4-year-old patient with C5-C6 flexion/distraction injury with bilateral jumped facets. Posterior cervical fixation was attempted; however, lateral mass fracture occurred during placement of screws. Using a wire-screw construct, an attempt was made to provide stable fixation. The patient was followed post-operatively for assessment of outcomes. After the patient had progressive kyphosis following initial closed reduction and external orthosis, internal reduction with fusion/fixation was performed. Lateral mass fracture occurred during placement of lateral mass screws. After placement of a sub-laminar wire-lateral mass screw construct, intra-operative evaluation determined stability. Post-operatively, the procedure resulted in stable fixation with evidence of bony fusion on follow-up. Pediatric subaxial cervical spine instrumentation provides rigid fixation however is technically difficult due to anatomic and instrumentation related constraints. In the presented patient, the wire-screw construct resulted in stable fixation and bony fusion on follow-up. A modified sublaminar wire-lateral mass screw construct is an example of a salvage technique that provides immediate stability in the event of instrumentation related lateral mass fracture.

Transforaminal lumbar interbody fusion

The transforaminal lumbar interbody fusion (TLIF) is a safe, effective, and versatile technique for treating many degenerative conditions in the lumbar spine. The disc space is accessed through a lateral-to-medial transforaminal corridor which has several advantages over direct posterior approaches. The major advantages of the TLIF procedure include a decrease in potential neurological injury and improvement in lordotic alignment. The purpose of this chapter is to discuss surgical technique, important technical nuances, and strategies for complication avoidance.

Magnetic Resonance Neurography of the Lumbar Plexus at the L4–5 Disc: Development of a Preoperative Surgical Planning Tool for Lateral Lumbar Transpsoas Interbody Fusion (LLIF)

Introduction The lateral transpsoas approach for lumbar interbody fusion (LLIF) is a minimally invasive surgical technique that is now frequently used to treat common spinal disorders. During LLIF, the course of the plexus within the surgical corridor places it at risk for iatrogenic intraoperative injury. Several previous studies have suggested that the risk of neurological injury during LLIF is higher at L4–L5. Current imaging techniques of assessing the proximity of neural tissue to the L4–L5 disc space have limited capabilities. Magnetic resonance neurography (MRN) is a noninvasive MR imaging tool developed for peripheral nerve imaging. A myriad of clinical applications exist including imaging assessment of lumbosacral plexopathies. In this study, we explored an additional clinical application for this technology as a preoperative planning tool for LLIF. Material and Methods Consecutive lumbar plexus MR neurograms (n = 27 patients, 54 sides) were studied. All scans were performed on a Siemens 3 T Skyra MRI scanner. The imaging protocol included axial and coronal T1-weighted, axial and coronal T2-weighted spectral adiabatic inversion recovery (SPAIR; Siemens Healthcare), and coronal T2-weighted 3D inversion recovery (3D SPACE; Siemens Healthcare) sequences. Following acquisition, the images were postprocessed using TeraRecon Aquarius iNtuition v4.4 to generate T1- and T2- color-coded fusion maps. 3D models of the lumbosacral plexus with attention to the L4–L5 interspace were generated using the GE AW Suite v2 (General Electric). The L4–L5 intervertebral space was divided into six zones according to Moro method. Zones I to IV were distributed equidistantly between the anterior and posterior margins. The position of the plexus and the shape of the psoas muscle at the L4–L5 interspace was evaluated and recorded. Results Direct imaging of the lumbar plexus using MR neurography revealed variability in the position of the plexus relative to the L4–L5 interbody space. In this series of 27 patients, there was significant variability in the anatomic position of the lumbar plexus from patient-to-patient and right-to-left in individual patients. The left-side lumbar plexus was identified in zones III (55%) and zone IV (44%) (p = 0.56). On the right side the plexus was most frequently identified in zones III (44%) or zone IV (44%) however was also identified in zone II (7.4%) or posterior (3.7%) (p = 0.009). Right–left symmetry of the plexus relative to the disc space was found in 44% of the subjects. There was no correlation between the position of the plexus and the shape the overlying psoas muscle identified. Conclusion MRN is a noninvasive imaging technique for visualizing the lumbosacral plexus. The course of the lumbosacral plexus traversing the L4–5 disc space may be more variable than has been suggested by previous studies. MRN may provide a more reliable means of preoperatively identifying the plexus when compared with current methods. The ability to assess the location of the plexus may aid in preoperative planning and reduce neurological complications.

E-062 True aneurysms of the posterior communicating artery: a systematic review and meta-analysis of individual patient data

Introduction The term ‘true’ posterior communicating artery (PCoA) aneurysm refers to an aneurysm that originates from the posterior communicating artery itself. Over the past decades, an increasing number of this type of posterior communicating artery aneurysms have been reported. We systematically reviewed all of these published data and conducted a meta-analysis on these individual patient data. Method A meta-analysis of individual patient data was conducted. Results Pooled data demonstrated that ‘true’ PCoA aneurysms represented about 1.3% (95% CI 0.8% to 1.7%) of all intracranial aneurysms and 6.8% (95% CI 4.3% to 9.2%) of all PCoA aneurysms. Mean age was 53.5 (53.5±15.4) years and ranged between 23 and 79 years. 49 of these reported aneurysms had the ruptured status, 44 (89.8%) were reported as ruptured and four (10.2%) were reported as unruptured. There were no significant differences in ruptured status between age (p=0.321), aneurysm side (p=0.537) and shape (p=0.408). No significant differences in complication rates were found between the different ruptured status (p=0.27) or operative modalities (p=0.878). Mean ages of those patients who had no complications and those who had complications were 53 (53±2.59) versus 53.2 (53.2±5.02) years (p =0.972). Conclusion We concluded that ‘true’ PCoA aneurysms represent about 1.3% of all intracranial aneurysms and 6.8% of all posterior communicating artery aneurysms. ‘True’ PCoA aneurysms are more prone to rupture compared with their counterpart junctional aneurysms. When surgical management is indicated, care should be taken in choosing the operative approach to avoid oculomotor nerve damage and to preserve perforating branches as much as possible. A good understanding of the location and configuration of the aneurysm neck before surgical treatment is critical in successful treatment of these lesions.Abstract E-062 Figure 1