Christina M. Walter

The surgical neurovascular anatomy relating to partial and complete sacral and sacroiliac resections: a cadaveric, anatomic study

PurposePelvic and sacral surgeries are considered technically difficult due to the complex multidimensional anatomy and the presence of significant neurovascular structures. Knowledge of the key neurovascular anatomy is essential for safe and effective execution of partial and complete sacral resections. The goal of this anatomic, cadaveric study is to describe the pertinent neurovascular anatomy during these procedures.MethodsThree embalmed human cadaveric specimens were used. Sacrectomies and sacroiliac joint resections were simulated and the structures at risk were identified. Both anterior and posterior approaches were evaluated.ResultsDuring sacroiliac joint resection, L5 nerve roots are at high risk for iatrogenic injury; the vasculatures at greatest risk are the common iliac vessels and internal iliac vessels with L5–S1 and S1–S2 high sacrectomies. Minor bleeding risk is associated with S2–S3 osteotomy because of the potential to damage superior gluteal vessels. S3–S4 osteotomy presents a low risk of bleeding. Adjacent nerve roots proximal to the resection level are at high risk during higher sacrectomies.ConclusionsSeveral sacrectomy techniques are available and selection often depends on the specific case and surgeon preference; nevertheless, anatomic knowledge is extremely important. Considering the highly variable anatomic relations of the vascular bundles, a preoperative evaluation with CT or MRI with vascular reconstruction may be helpful to decrease bleeding risk by preemptively binding the internal iliac vessels in cases where higher tumors are present. To decrease the risk of damaging nerve roots, it is recommended to perform the resection as close to the involved foramina as possible.

Epidemiology of the Reported Severity of Copperhead (Agkistrodon contortrix) Snakebite

Objective The goal of this study was to analyze trends in the annual rates of reported medical outcomes of US copperhead (Agkistrodon contortrix) snakebites published in the annual reports of the American Association of Poison Control Centers in the course of 26 years. Methods This was a retrospective analysis of medical outcomes for copperhead snakebite victims who developed fatal, major, moderate, minor, or no effects. The annual rates for these medical outcomes were calculated by dividing the annual number of patients in each outcome category by the total annual number of people reported as being bitten by copperheads. Poisson and negative binomial regression were used to examine trends in annual rates. Results From 1983 through 2008, the incidence rate of copperhead snakebites causing no effect significantly decreased by 12.1%/year (incidence rate ratio [IRR] 0.879; 95% confidence interval [CI] 0.848–0.911]. From 1985 through 2008, the incidence rate of minor outcomes significantly decreased by 2.3%/year (IRR 0.977; 95% CI 0.972–0.981), whereas the rate of moderate outcomes significantly increased by 2.8%/year (IRR 1.028; 95% CI 1.024–1.033). The rate of major outcomes did not significantly change. One fatality was reported in 2001. Conclusions Annual rates of copperhead snakebites producing no effects and minor outcomes significantly decreased, those producing moderate outcomes significantly increased, and those producing major outcomes did not significantly change in a 26-year period.

Bracing After Surgical Stabilization of Thoracolumbar Fractures: A Systematic Review of Evidence, Indications, and Practices.

BACKGROUND The role of spinal orthotic braces after surgical stabilization is not clearly defined. We systematically reviewed the published literature to determine patterns of practice, indications, and current evidence for the use of orthotic braces after surgical thoracolumbar fracture stabilization. METHODS A search was performed for publications including descriptions of postoperative management and outcomes after surgical stabilization of thoracolumbar injuries. Differences between wearing versus not wearing a postoperative brace were examined with regard to loss of deformity correction, pain, return to previous work activity, functional improvement, instrumentation failure rate, pseudoarthrosis, and the percentage of reported complications. RESULTS This search yielded 76 pertinent studies. Postoperative bracing (POB) was adopted in 62 studies for a median wear time of 13.3 weeks. No significant differences in terms of pain, return to work, Frankel score improvement, or instrumentation failure were found between the POB and non-POB groups. Loss of surgical kyphotic reduction was slightly greater in the POB group (4.79° vs. 3.77°; P < 0.001). The overall complication rate was also higher in the POB group (16.3% vs. 11.9%; P < 0.01). The pseudoarthrosis rate was lower in the braced group (2.4% vs. 6.0%; P < 0.001). CONCLUSIONS Most surgeons use braces for 3 months after surgical thoracolumbar fracture stabilization. Given the lack of clinical or biomechanical evidence for this, and the additional costs and potential discomfort to patients, further investigation is warranted to determine when and if POB for surgically stabilized thoracolumbar fractures is indicated. Controlled studies should include a careful analysis of pseudoarthrosis and complication rates.

Minimally invasive lateral transpsoas interbody fusion using a stand-alone construct for the treatment of adjacent segment disease of the lumbar spine: Review of the literature and report of three cases.

We describe 3 patients who presented with radiographic signs and clinical symptoms of adjacent segment disease several years after undergoing L4-S1 posterior pedicle screw fusion. All patients underwent successful lateral lumbar interbody fusion (LLIF) at 1-2 levels above their previous constructs, using stand-alone cages, with complete resolution of radiculopathy and a significant improvement in low-back pain. In addition to a thorough analysis of these cases, we review the pertinent literature regarding treatment options for adjacent segment disease and the applications of the lateral lumbar interbody technique.

Posterior atlantoaxial fixation: A cadaveric and fluoroscopic step-by-step technical guide.

Background: Atlantoaxial surgical fixation is widely employed treatment strategy for a myriad of pathologies affecting the stability of the atlantoaxial joint. The most common technique used in adults, and in certain cases in children, involves a posterior construct with C1 lateral mass screws, and C2 pars or pedicle screws. This technical note aims to provide a step-by-step guide to this procedure using cadaveric and fluoroscopic images. Methods: An embalmed, human, cadaveric, specimen was used for this study. The subject did not have obvious occipital-cervical pathology. Dissections and techniques were performed to mimic actual surgical technique. Photographs were taken during each step, and the critical aspects of each step were highlighted. Fluoroscopic images from a real patient undergoing C1/C2 fixation were also utilized to further highlight the anatomic-radiographic relationships. This study was performed without external or industry funding. Results: Photographic and radiographic pictures and drawings are presented to illustrate the pertinent anatomy and technical aspects of this technique. The nuances of each step, including complication avoidance strategies are also highlighted. Conclusions: Given the widespread utilization of this technique, described step-by-step guide is timely for surgeons and trainees alike.

Posterior longitudinal ligament resection or preservation in anterior cervical decompression surgery

We reviewed the literature to determine differences in clinical outcomes for the removal or preservation of the posterior longitudinal ligament (PLL) in anterior cervical discectomy and fusion (ACDF). The outcomes are surgeon and case-dependent for both practices. A literature review was performed in PubMed from the years 1960 to 2014 to identify studies describing surgeries where the PLL was removed or preserved during ACDF. Searches were performed using Medical Subject Headings (MeSH) and references included in the reviewed articles were also considered. Additionally we searched recent articles that cited those from the original search. The search yielded 79 articles and 115 pertinent citations. These 194 articles were reviewed for specific discussions of PLL resection or preservation. Four articles containing 122 patients were included in the final analysis. In 69 patients the PLL was removed and in 53 the PLL was preserved. Both groups improved in clinical scores during follow up. One patient in the PLL removal group had a cerebrospinal fluid leak. MRI and correlative outcome data suggest that a non-ossified PLL itself does not contribute to significant cord compression. Postoperative MRI of patients with the PLL removed showed a larger spinal cord diameter. Resection of the PLL is safe and common in ACDF surgery but there does not appear to be a demonstrable clinical difference in patients where it is resected. The ultimate decision is likely surgeon and case-dependent. Randomized trials could further determine the importance of PLL removal in ACDF treated patients.

Anatomic considerations of the anterior upper cervical spine during decompression and instrumentation: A cadaveric based study

We evaluated the anatomical considerations specific to the high anterior retropharyngeal approach to the cervical spine. Surgical exposure of the anterior upper cervical spine can sometimes be challenging due to the surrounding neurovascular structures. Using three adult cadavers, we performed high anterior retropharyngeal cervical dissection of the left and right side for a total of six approaches (six sides). During the dissection, all important neurovascular elements were noted and photographed, and anatomical relationships to the spinal vertebral bodies and disc spaces were analyzed. There are certain anatomic considerations that are unique to the high anterior cervical spine. The unique structures include the hypoglossal nerve and the superior thyroid artery/nerve. Only the superior thyroid artery in this region has numerous anatomical variations. Awareness of other structures, including the carotid artery, recurrent laryngeal nerve, and esophagus also remains important. Awareness of the anatomical structures in the anterior upper cervical spine is essential for performing safe anterior upper cervical spinal surgery, avoiding serious complications.

Combined posterior hemiosteotomies and stabilization with lateral thoracotomy for en bloc resection of thoracic paraspinal primary bone tumors: technical note

Primary bone tumors of the spine are rare entities with a poor prognosis if left untreated. En bloc excision is the preferred surgical approach to minimize the rate of recurrence. Paraspinal primary bone tumors are even less common. In this technical note the authors present an approach to the en bloc resection of primary bone tumors of the paraspinal thoracic region with posterior vertebral body hemiosteotomies and lateral thoracotomy. They also describe 2 illustrative cases.

Prognostic factors in traumatic atlanto-occipital dislocation

Traumatic atlanto-occipital dislocation (AOD) is an ominous injury with high mortality and morbidity in trauma patients. Improved survival has been observed with advancements in pre-hospital and hospital care. Furthermore, high quality imaging studies are accessible at most trauma centers; these are crucial for prompt diagnosis of AOD. The objective of this study is to perform a comprehensive literature review of traumatic AOD, with specific emphasis on identifying prognostic factors for survival. A review of the literature was performed using the Medline database for all traumatic atlanto-occipital articles published between March 1959 and June 2015; 141 patients from 60 total studies met eligibility criteria for study inclusion. A binary logistic regression model was utilized to identify prognostic factors. The analysis assessed age, sex, spinal cord injury (SCI), traumatic brain injury (TBI), polytrauma injury (PI), and Traynelis AOD Classification. Only TBI was statistically significantly associated with death (OR 8.05 p<0.05); SCI did not reach statistical significance for predicting mortality in AOD patients (OR 1.25 p>0.05). Age, sex, PI, and Traynelis AOD Classification did not meet significance to predict mortality in AOD patients. We found that patients with TBI are eight times more likely to die than patients without TBI. A high degree of suspicion for AOD during pre-hospital care, as well as, prompt diagnosis and management in the trauma center play a key role in the treatment of this devastating injury. The relationship between survival and factors such as TBI and SCI should be further explored.

Letter: Rerupture of a Blister Aneurysm After Treatment With a Single Flow-Diverting Stent

To the Editor: We read the recent article by Mazur et al1 with great interest; in this article, the authors described the case of a 29-year-old male who presented with a ruptured internal carotid artery blisterlike aneurysm treated with a single Pipeline Flex (Medtronic, Dublin, Ireland), complicated by aneurysm rupture postoperatively. This report perfectly exemplifies the challenges faced by vascular neurosurgeons in the treatment of blister aneurysms. Despite tremendous advances in microsurgical and endovascular techniques, blister aneurysms still lack a failsafe treatment option.