Multi-institutional review of characteristics and management of gunshot wounds to the spine.

BACKGROUND CONTEXT: Gunshot wounds (GSWs) to the vertebral column represent an important cause of morbidity and mortality in the United States, constituting approximately 20% of all spinal injuries. The management of these injuries is an understudied and controversial topic, given its heterogeneity and lack of follow-up data. PURPOSE: To characterize the management and follow-up of GSWs to the spine. STUDY DESIGN/SETTING: A multi-institutional retrospective review of the experience of two urban Level 1 trauma centers. PATIENT SAMPLE: Patients with GSWs to the spine between 2010-2021. OUTCOME MEASURES: Measures included work status, follow-up healthcare utilization, and pain management were collected. METHODS: Charts were reviewed for demographics, injury characteristics, surgery and medical management, and follow-up. Statistical analysis included T-tests and ANOVA for comparisons of continuous variables and chi-square testing for categorical variables. All statistics were performed on SPSS v24 (IBM, Armonk, NY). RESULTS: A total of 271 patients were included for analysis. The average age was 28 years old, 82.7% of patients were black, 90% were male, and 76.4% had Medicare/Medicaid. The thoracic spine (35%) was most commonly injured followed by lumbar (33.9%) and cervical (25.6%). Cervical GSW was associated with higher mortality (p<.001); 8.7% of patients developed subsequent osteomyelitis/discitis, 71.3% received prophylactic antibiotics, and 56.1% of cervical GSW had a confirmed vertebral or carotid artery injury. ASIA scores at presentation were most commonly A (26.9%), D (20.7%), or E (19.6%), followed by C (7.4%) and B (6.6%). 18.8% of patients were unable to be assessed at presentation. ASIA score declined in only 2 patients, while 15.5% improved over their hospital stay. Those who improved were more likely to have ASIA B injury (p<.001). Overall, 9.2% of patients underwent spinal surgery. Of these, 33% presented as ASIA A, 21% as ASIA B, 29% as ASIA C, and 13% as ASIA D. Surgery was not associated with an improvement in ASIA score. CONCLUSIONS: Given the ubiquitous and heterogeneous experience with GSWs to the spine, rigorous attempts should be made to define this population and its clinical and surgical outcomes. Here, we present an analysis of 11 years of patients presenting to two large trauma centers to elucidate patterns in presentation, management, and follow-up. We highlight that GSWs to the cervical spine are most often seen in young black male patients. They were associated with high mortality and high rates of injury to vertebral arteries and that surgical intervention did not alter rates of discitis/osteomyelitis or propensity for neurologic recovery; moreover, there was no incidence of delayed spinal instability in the study population.

Remote surgical education using synthetic models combined with an augmented reality headset.

Objective: The objective was to investigate the use of an augmented reality headset to remotely train clinicians on medical devices using anatomic models. Design: Disease-specific phantoms were developed to train physicians in mpMRI-guided fusion prostate biopsy, brachytherapy, and rectal spacer insertion. Training was remotely demonstrated using 1-way virtual video conferencing format. Participants responded to an educational content survey. A heads-up display with software and augmented reality was used for remote 2-way training with the proctor and student using on their own phantoms. Setting: The virtual video meeting took place during a prostate cancer conference in 2020, while the augmented reality training occurred in 2021. The proctor and student wore a heads-up display containing a projector and webcam where the ultrasound image was displayed onto a see-through optic along with the physician's hands. The heads-up display allowed the proctor to teach by line-of-sight while the student watched and repeated the steps. Participants: Faculty with expertise with the medical devices used in these procedures provided training to urologists unfamiliar with these techniques. Results: Participants responded that the 1-way training on the phantoms was realistic and mimicked human tissue. A total of 70.9% requested more training or training on the phantoms. The remote training platform was successfully beta tested at the 2 locations in transperineal prostate biopsy and rectal spacer insertion. Conclusion: Remote training using augmented reality eliminates the need for travel. For training programs and workshops, this technology may mitigate the risk of infectious exposures, reduce training cost, and increase proctor availability, allowing training from their own institution or clinic.This investigation qualifies for the Accreditation Council for Graduate Medical Education competency in medical knowledge.

Neuromuscular choristoma-associated desmoid-type fibromatosis: Establishing a nerve territory concept.

INTRODUCTION: Desmoid-type fibromatosis (DTF) frequently arises in patients with neuromuscular choristoma (NMC). We hypothesize that NMC-associated DTF occurs in soft tissues innervated by the NMC-affected nerve, and arises from CTNNB1-mutated (myo) fibroblasts within or directly adjacent to the NMC. MATERIALS AND METHODS: A retrospective review of patients treated at our institution was performed for patients with biopsy-confirmed diagnosis of NMC-DTF. Clinical presentation, physical examination, electrodiagnostic findings and radiological features (MR and FDG PET/CT images for each NMC-DTF) and pathologic re-review of available materials were analyzed. A literature review was also performed. RESULTS: Eight patients from our institution met the inclusion criteria. All patients presented with neuropathic symptoms and soft tissue or bone changes in the nerve territory innervated by the NMC. All MR images (N=8 cases) showed the characteristic features of NMC, and also showed direct contact between unifocal (N=5) or multifocal (N=3) DTF(s) and the NMC-affected nerve NMC. FDG PET/CT (N=2 cases) showed diffuse, increased FDG uptake along the entire affected nerve segment, contiguous with the FDG-avid DTF. In all cases, the DTFs arose in the soft tissues of the NMC-affected nerve's territory. No patient developed DTF at any other anatomic site. CONCLUSIONS: These data demonstrate that NMC-DTF arises solely within the NMC-affected nerve territory, and has direct contact with the NMC itself. Based on all these findings and the multifocality of NMC in several cases, we recommend imaging and surveillance of the entire NMC-affected nerve (from spine to distal extremity) to identify clinically-occult DTF in patients with NMC.

Go for the Gold: A "Plane" and Simple Technique for Resecting Benign Peripheral Nerve Sheath Tumors.

BACKGROUND: Intraneural dissection is a useful technique for achieving gross total resection and preserving functional fascicles for peripheral nerve tumors. Finding the correct tissue plane is the critical step for safe successful enucleation. The authors hypothesized that the yellow color of benign nerve tumors can be used to identify surgical planes. OBJECTIVE: To describe a technique to find the correct intraneural dissection plane based on a quantified yellow appearance during resection of benign peripheral nerve sheath tumors. METHODS: Intraoperative photographs were reviewed to determine the percentage of yellow that tumors appeared at different phases of surgery. A technique was developed to quantitatively measure the amount of yellow using Photoshop. Previously published journal articles containing color images of peripheral nerve tumor resections were also analyzed for yellow tumor color. RESULTS: There were 24 patients with suitable images to permit measurement of color for 3 steps of the procedure. The average percentages of yellow for tumor exposure, tumor resection, and removed specimen were 36.5%, 59.1%, and 80.4%, respectively (P < .001). Three publications were found that contained high-quality images of at least 2 phases of the surgery with average yellow content of 47.4% and 84% (P < .01). CONCLUSION: The simple observation that a benign nerve sheath tumor is yellow in color can be used to guide surgical resection and achieve excellent outcomes. Intraneural dissection through the pseudocapsule should be pursued layer by layer until a yellow true capsule is found. By sparing functional nervous tissue within the pseudocapsule, this technique may lead to improved neurological outcomes.

Joint Outcomes Following Surgery for Superior Tibiofibular Joint-Associated Peroneal Intraneural Ganglion Cysts.

BACKGROUND: Intraneural ganglion cysts are joint-connected, with the primary pathology residing in the associated joint. For peroneal intraneural ganglion cysts, the surgical strategy can include resection of the synovial surface of the superior tibiofibular joint (STFJ). However, the rate of instability postoperatively is unclear. OBJECTIVE: To evaluate the rate of STFJ instability, following surgery for peroneal intraneural ganglion cysts. The second goal of the study was to assess the relationship between volume of resection of the STFJ and risk of extraneural recurrence. METHODS: We performed a retrospective analysis of a cohort of patients with peroneal intraneural ganglion cysts. We analyzed clinical factors, including recurrence, and assessed the rate of postoperative STFJ instability. We created 3-dimensional models of the STFJ pre- and postoperatively to compare the volume of resection in recurrent cases and nonrecurrent cases using a case-control design. RESULTS: The total cohort consisted of 65 subjects. No patient had evidence of radiological or clinical instability of the STFJ postoperatively. Extraneural radiological recurrence occurred in 6 (9%) patients. No intraneural recurrences were observed. The average volume of resection for patients with recurrence was 1349 mm3 (SD = 1027 mm3) vs 3018 mm3 (SD = 1433 mm3) in controls that did not have a recurrence (P = .018). CONCLUSION: This study supports performing an aggressive STFJ resection to minimize the risk of extraneural recurrence. Superior tibiofibular joint resection is not associated with postoperative joint instability. A smaller volume resection is correlated with recurrence risk.

Interfascicular Resection of Benign Peripheral Nerve Sheath Tumors.

BACKGROUND: Interfascicular resection is a surgical technique used to safely treat benign peripheral nerve sheath tumors through careful dissection of functional neural elements off the tumor surface1,2. DESCRIPTION: Proper operative technique is essential to improving symptoms, preserving neurologic function, and minimizing the chance for recurrence. Accurate tumor localization, ideal patient positioning, and placement of a longitudinal incision permit adequate exposure. Prior to tumor resection, normal nerve should be identified proximally and distally and controlled with vessel loops. This allows functional fascicles streaming around the tumor in the pseudocapsule to be visualized during resection. A fascicle-free window is identified on the tumor surface through visual inspection and intraoperative neurophysiology monitoring if desired. The pseudocapsule layers are divided with a sharp instrument until a smooth and shiny true capsule layer is found. This plane should have minimal resistance and is developed circumferentially until the tumor can be enucleated in toto. At the poles of the tumor, a single nonfunctional nerve fascicle that courses into the tumor is typically found. If there is >1 fascicle running into the tumor, further pseudocapsule layers should be undermined to sweep fascicles off the true capsule surface. The entering-exiting fascicle can be tested for function and is cut sharply. The specimen should be sent to pathology for permanent sectioning. The sides of the pseudocapsule are spread in opposite directions to evaluate for residual tumor, and any remaining tumor is removed if it can be done safely. Meticulous hemostasis is achieved, and the surgical site is closed in anatomical layers. ALTERNATIVES: Pain is the most common presenting symptom, and neuroleptic medications should be used in escalating dosage prior to surgical intervention. Nonoperative medical therapy does not typically result in symptom freedom, and patients often opt for resection. For tumors that are suspected of being malignant, an image-guided percutaneous or open biopsy and staging (positron emission tomography and/or computed tomography scans of the chest, abdomen, and pelvis) are recommended prior to treatment planning. For symptomatic benign extremity lesions, surgical resection is the treatment of choice, and adjuvant therapies like radiation and/or chemotherapy are not recommended. For malignant lesions, more aggressive surgery (wide resection or amputation) and preoperative, intraoperative, or postoperative radiation with or without chemotherapy are often utilized. RATIONALE: The treatment approach depends on a variety of presenting features such as onset, progression, symptom severity, tumor size, location, imaging features, presence of a syndrome, and patient age. There is little benefit from the resection of an incidentally found, small, nongrowing lesion. The most common reasons for removal of extremity lesions are a painful mass and/or radiating "nerve" pain. There is a high likelihood of relieving the symptoms and minimizing the risk of recurrence, and a relatively low risk of causing neurologic injury. The procedure provides a definitive diagnosis. For patients with severe pain, progressive weakness, rapid tumor growth, or concerning imaging characteristics, biopsy should be considered to determine malignant potential.

Clinical and Magnetic Resonance Imaging Longitudinal Follow-up of Neuromuscular Choristomas.

INTRODUCTION: The natural history of growth and radiologic progression of neuromuscular choristomas (NMCs) remain unknown. The purpose of this study was to describe the radiologic growth pattern of NMCs and to determine how the pattern of growth relates to clinical progression. METHODS: A retrospective review was performed for patients with a confirmed diagnosis of NMC and at least 2 years of radiologic (magnetic resonance imaging [MRI]) follow-up. Medical records, including physical examinations and radiologic studies, were reviewed in detail. The NMC length and transverse dimensions were compared between serial MRI examinations. RESULTS: Eleven patients with a mean radiologic follow-up time of 5.6 years (range 2-19 years) were identified. Motor deficits occurred in 10 patients (90%), sensory deficits in 5 patients (45%), and neuropathic pain in 4 (36%) patients. Eight patients (73%) presented with manifestations of limb undergrowth, 2 (18%) with congenital hip dysplasia, and 1 with a cavus foot deformity. Progression of motor and sensory deficits was observed in 5 (45%) and 1 (9%) patients, respectively. The maximal length and height of the NMC was significantly (P < 0.05) longer (initial 218 ± 118 mm vs. follow-up 270 ± 135 mm) and larger (20 ± 10 mm vs. 24 ± 14 mm) on the follow-up scan. MRI demonstrated abnormalities that were in continuity along the longitudinal extent of the NMC. CONCLUSIONS: According to this small but relatively long-term follow-up cohort, the growth pattern of this lesion is slow but progressive. We found a longitudinal continuity pattern of growth in all MRI scans, often spanning a great distance.

Extended-release gabapentin for failed back surgery syndrome: results from a randomized double-blind cross-over study.

Persistent pain after lumbar surgery (failed back surgery syndrome [FBSS]) remains a leading indication for chronic analgesia. However, no analgesics have proven efficacious for this condition. Although trials have evaluated gabapentinoids for chronic low back pain, none of these trials focused solely on FBSS. This randomized, double-blind cross-over trial evaluated the efficacy of gabapentin (1800 mg/day) for FBSS. Eligible patients had a diagnosis of FBBS, an average daily pain score of at least 4 of 10, a neuropathic pain component (indicated by the PainDetect), and reported at least half of their pain radiating in their lower extremity. Participants were randomized to 2, 7-week study periods separated by a 10-day washout. The primary outcome measure was a 0 to 10 numeric rating scale (NRS) of average pain. Secondary measures included the McGill Pain Questionnaire and Patient Global Impression of Change. The treatment effect was analyzed using a mixed effect analysis of covariance with fixed effects for treatment, period, and baseline 7-day mean NRS pain score and a random effect for the participant. The outcome of the model was the mean 7-day NRS score for the last 7 days of each treatment period. Thirty-two participants were randomized and included in the primary analysis; 25 completed both study periods. No difference was detected between treatments on any outcome measure, including the primary (least square mean difference in NRS: -0.01 confidence interval: [-0.22 to 0.20]). Given the escalating rate of complex lumbar surgery, future research to develop novel therapies for this prevalent syndrome is needed.

Preoperative Planning Using 3-Dimensional Printing for Complex Paraspinal Schwannoma Resection: 2-Dimensional Operative Video.

Schwannomas are benign peripheral nerve sheath tumors that are typically round, smooth, and straightforward to resect. Occasionally they are more complicated to resect because of their size, location, degree of bony erosion, and vascular or neural compression. These complex lesions frequently require multidisciplinary surgical teams in order to decrease surgical morbidity. Historically, surgical planning consisted of imaging review and verbal communication among team members. 3-dimensional (3D) printing offers a new method for preoperative planning and is becoming more popular in Neurosurgery. This video demonstrates the use of 3D printing for complex paraspinal tumors in the cervical, thoracic, and sacral regions. The Institutional Review Board Office for Human Research Protection does not require approval for single participant case studies, or a case series with multiple participants. The subjects involved in this study were not identifiable and the general surgical consent form included permission for intraoperative photos.

Stimulation Contractility Gradient of a Neuromuscular Choristoma Within the Sciatic Nerve: 2-Dimensional Operative Video.

Neuromuscular choristoma (NMC) is a rare congenital nerve lesion that is classified by the presence of heterotopic muscle fibers intercalated within nerve fascicles.1 The presence of NMC typically causes progressive neuropathy and bony/soft tissue undergrowth, often leading to a shortened atrophic limb.2,3 The typical appearance of NMC on magnetic resonance imaging is an enlarged fusiform nerve that exhibits minimal gadolinium enhancement.4 While there is increasing documentation of pathognomonic clinical and radiographic features for various diffuse fusiform peripheral nerve lesions, nerve biopsy is still occasionally required for some patients given the rarity of these diseases and progressive neuropathic features.The intraoperative appearance of NMC and its unique electrical stimulation properties are quite interesting. Intrafascicular replacement of nerve by skeletal muscle gives the nerve a red beefy color and causes the fascicles to contract with electrical stimulation.5 In this video, we demonstrate the intraoperative appearance and contractile properties of NMC in a 60-yr-old woman with progressive sciatic neuropathy. Histologic and immunohistochemical studies identified a gradient of intralesional mature skeletal muscle within the NMC, with substantially fewer desmin-positive skeletal muscle fibers in the distal aspect. A gradient of contractility with intraoperative stimulation seemed to correlate with this pathology. These findings suggest that the lesional extent of NMC may not be clinically or grossly evident, reflecting a varying distribution of skeletal muscle within the affected nerve.The Mayo Clinic Institutional Review Board Office for Human Research Protection does not require approval for single participant case studies. The subject involved in this study was not identifiable and the general surgical consent form included permission for intraoperative photos and video.

Multimodal Imaging Aids in the Diagnosis of Perineural Spread of Prostate Cancer.

BACKGROUND: The perineural spread of prostate cancer into pelvic peripheral nerves is a rare, but increasingly recognized, entity. This form of metastasis invades the lumbosacral plexus via the splanchnic nerves innervating the prostate. The prevalence of perineural spread is likely underappreciated, and further imaging-based studies are needed to elucidate its true frequency. METHODS: A retrospective review was performed using an institutional radiology database. Medical reports from patients with prostate cancer who had undergone positron emission tomography (PET) imaging were queried for terms suggestive of perineural spread. PET and magnetic resonance imaging (MRI) from the identified patients were blindly reviewed for peripheral nerve involvement by 2 nuclear medicine and 2 musculoskeletal radiologists. RESULTS: A total of 22 patients were identified. After review by the radiologists, 16 patients had positive findings of perineural spread found on PET and 15 had abnormalities found on MRI involving lumbosacral plexus neural elements. All patients with biopsy-proven neoplastic perineural spread (including 1 patient with malignant peripheral nerve sheath tumor) had positive findings on both PET and MRI. All patients with biopsy-proven inflammatory lesions had negative PET and variable MRI findings. CONCLUSIONS: The perineural spread of prostate cancer might be more common than previously thought. The use of multimodal imaging for patients suspected of having perineural spread should be a part of the treatment algorithm. Targeted fascicular biopsy might be indicated for patients with progressive neurological deficit and an unclear diagnosis.

Recurrent desmoid-type fibromatosis associated with underlying neuromuscular choristoma.

OBJECTIVE: Desmoid-type fibromatosis (DTF) presents a therapeutic dilemma. While lacking metastatic potential, it is a locally aggressive tumor with a strong propensity for occurrence near nerve(s) and recurrence following resection. In this study, the authors introduce the association of an occult neuromuscular choristoma (NMC) identified in patients with DTF. METHODS: After experiencing a case of DTF found to have an occult NMC, the authors performed a retrospective database review of all other cases of biopsy-proven DTF involving the extremities or limb girdles in patients with available MRI data. Two musculoskeletal radiologists with expertise in peripheral nerve imaging reviewed the MRI studies of the eligible cases for evidence of previously unrecognized NMC. RESULTS: The initial case of a patient with an occult sciatic NMC is described. The database review yielded 40 patients with DTF-18 (45%) in the upper limb and 22 (55%) in the lower limb. Two cases (5%) had MRI findings of NMC associated with the DTF, one in the proximal sciatic nerve and the other in the proximal tibial and sural nerves. CONCLUSIONS: The coexistence of NMC may be under-recognized in a subset of patients with extremity DTF. This finding poses implications for DTF treatment and the likelihood of recurrence after resection or biopsy. Further study may reveal crucial links between the pathogenesis of NMC and DTF and offer novel therapeutic strategies.

Analysis of Peripheral Nerve Schwannoma Pseudocapsule.

BACKGROUND: Using proper surgical technique, schwannomas can be resected safely, with a low recurrence rate and high likelihood of improvement in symptomatology. There are multiple peritumoral tissue layers, and finding the correct plane is critical to safe tumor enucleation. The contents of the pseudocapsule tissue surrounding a schwannoma are not well described, and the consequences of resecting or leaving pseudocapsules are unknown. METHODS: An institutional database was searched for any pathology reports that contained both of the words "schwannoma" and "capsule." Charts and histopathologic specimens were reviewed to determine the contents of various tissue layers and determine if there was any correlation between pseudocapsular contents and clinical outcomes. RESULTS: A pseudocapsule was separately sent for pathology in 36 patients during schwannoma resection. Ten pseudocapsule specimens contained microscopic foci of tumor. In a separate 6 patients, there was evidence of nerve fascicles. There were no correlations between the tumor or nerve in the pseudocapsule and postoperative neurologic deficits. After an average follow-up time of 3.1 years, no patients developed a recurrence either clinically or on follow-up imaging (imaging available in 52.7%). Histopathologically, the pseudocapsule was made of dense hypocellular collagen and occasionally contained arteries, veins, and nerve fascicles. CONCLUSIONS: The pseudocapsule surrounding a schwannoma occasionally contained nerve tissue and blood vessels. While a microscopic focus of tumor was often found in this tissue layer, recurrence is exceedingly rare and did not occur in this case series. The risk of undue pseudocapsule dissection likely outweighs any negligible benefit from microscopic cytoreduction.

Extensive perineural spread of an intrapelvic sciatic malignant peripheral nerve sheath tumor: a case report.

Perineural spread has been described in multiple neoplasms of neural and non-neural origin. The peripheral nervous system may represent a highway by which tumors can spread throughout the body. Malignant peripheral nerve sheath tumor (MPNST) is a neoplasm arising from peripheral nerves with high rates of local recurrence and distant metastases, leading to a poor 5-year overall survival. In many cases, the optimal treatment involves wide en bloc excision with negative margins as well as chemotherapy and radiation. Even in cases of negative surgical margins, recurrence rates are high, suggesting possible skip lesions or very distant infiltration along the involved nerve. We report a case of high-grade MPNST of the sciatic nerve with post-mortem dissection and histopathologic characterization of perineural spread of microscopic disease to sites significantly proximal and distal to areas with evidence of gross disease, which may help to explain the high rates of local and distal recurrence in MPNST.

Targeted fascicular biopsy in a patient with prostate cancer.

Patients who present with a history of cancer and the new onset of lumbosacral or peripheral neuropathy should be evaluated for the potential of metastasis. Targeted fascicular biopsy can be useful to diagnose atypical lesions within peripheral nerves in patients with major or progressive neurological deficits. In this video, the authors demonstrate the technique of targeted fascicular biopsy of the sciatic nerve in a 63-year-old man with a history of prostate cancer. The video can be found here: https://youtu.be/PTOX9XxNBDU .

Intraoperative intravenous fluorescein as an adjunct during surgery for peroneal intraneural ganglion cysts.

The intraoperative use of intravenous fluorescein is presented in a case of peroneal intraneural ganglion cyst. When illuminated with the operative microscope and yellow filter, this fluorophore provided excellent visualization of the abnormal cystic peroneal nerve and its articular branch connection. The articular (synovial) theory for the pathogenesis of intraneural cysts is further supported by this pattern of fluorescence. Further, our report presents a novel use of fluorescein in peripheral nerve surgery.

Ectopic brain tissue in the trigeminal nerve presenting as rapid-onset trigeminal neuralgia: case report.

The authors report the case of a 52-year-old man who presented with rapid-onset lancinating facial pain consistent with trigeminal neuralgia. Magnetic resonance imaging revealed a nonenhancing small lesion on the right trigeminal nerve concerning for an atypical schwannoma or neuroma. The patient underwent resection of the mass via a right retrosigmoid approach. His facial pain completely resolved immediately postoperatively and had not recurred at 6 months after surgery. The mass was consistent with normal brain tissue (neurons and glial cells) without evidence of mitoses. A final histopathological diagnosis of ectopic brain tissue with neural tissue demonstrating focal, chronic T-cell inflammation was made. The partial rhizotomy during resection was curative for the facial pain. To the authors' knowledge, this is the first report of neuroglial ectopia causing trigeminal neuralgia.

Accessory neuropathy after sternotomy: Clinico-anatomical correlation supporting an inflammatory cause.

Inflammatory etiologies are becoming increasingly recognized as explanations of some neuropathies, especially those occurring in the perioperative period. Although "brachial neuritis" is known to affect extraplexal nerves, accessory nerve palsy following median sternotomy has been attributed to stretch on the nerve. To better elucidate stretch as a potential cause, a cadaveric study was performed. Two patients who developed accessory nerve palsy following median sternotomy are presented to illustrate features consistent with the diagnosis of a perioperative inflammatory neuropathy. Five adult unembalmed cadavers underwent exposure of the bilateral accessory nerves in the posterior cervical triangle. A median sternotomy was performed and self-retaining retractors positioned. With the head in neutral, left rotation and right rotation, retractors were opened as during surgery while observing and recording any accessory nerve movements. The self-retaining sternal retractors were fully opened to a mean inter-blade distance of 13 cm. Regardless of head position, from the initial retractor click to maximal opening there was no gross movement of the accessory nerve on the left or right sides. Opening self-retaining sternal retractors does not appear to stretch the accessory nerve in the posterior cervical triangle. Based on our clinical experience and cadaveric results, we believe that inflammatory conditions, (i.e., idiopathic brachial plexitis) can involve the accessory nerve, and might be triggered by surgical procedures. Clin. Anat. 31:417-421, 2018. © 2017 Wiley Periodicals, Inc.

Predictive multivariate regression to increase the specificity of carotid duplex ultrasound for high-grade stenosis in asymptomatic patients.

BACKGROUND: Carotid duplex ultrasound (CDUS) is commonly used to screen for carotid artery stenosis. Specificities of CDUS criteria however are lower than sensitivities, potentially resulting in false-positive examinations with subsequent unnecessary imaging or surgery. Our objective was to establish a multivariate logistic regression to increase the specificity of CDUS for high-grade (≥70%) stenosis. METHODS: A retrospective review collected CDUS velocities and radiographic measurements from patients who underwent both CDUS and computed tomography angiography (CTA). After stratification with standard CDUS criteria, a logistic regression was created using peak systolic velocity (PSV), end diastolic velocity (EDV), and PSV ratio (PSV of internal carotid artery [ICA]/PSV of common carotid artery [CCA]) as predictor variables. A receiver operating characteristic curve was generated to test the model's predictive ability. A cutoff probability for unequivocal high-grade stenosis was chosen based on optimal specificity. The regression model was applied to patients with equivocal high-grade stenosis. Probabilities for detection of high-grade stenosis were calculated. Descriptive statistics were generated to quantify the accuracy of the model. RESULTS: A total of 244 vessels were included. Standardized velocity criteria for ≥70% stenosis yielded a sensitivity of 90.6% (95% confidence interval [CI], 82.3-95.6%), specificity of 63.5% (95% CI, 55.4-70.5%), positive predictive value (PPV) of 57.0% (95% CI, 48.8-65.5%), and negative predictive value (NPV) of 92.7% (95% CI, 85.8-96.5%). Regression analysis produced a model for predicting the probability of high-grade stenosis defined as probability = logit(-1) (-4.97 + [0.00938 × PSV] + [0.0135 × EDV] + [0.103 × PSV ICA/CCA ratio]). A cutoff probability of 0.65 for high-grade stenosis yielded a sensitivity of 54.7% (95% CI, 43.9-65.0%), specificity of 94.3% (95% CI, 89.3-97.2%), PPV of 83.9% (95% CI, 71.6-91.9%), and NPV of 79.3% (95% CI, 72.8-84.5%). A cutoff PSV of 400 cm/sec was chosen for unequivocal stenosis of ≥70%. A total of 94 patients were found to meet criteria for high-grade stenosis (PSV ≥ 230 cm/sec) but fall short of criteria for unequivocal high-grade stenosis (PSV < 400 cm/sec). Application of the regression model resulted in identification of 15 patients with probability ≥0.65 for high-grade stenosis and 79 patients with probability <0.65. This resulted in a 16% potential reduction in CTA scans. CONCLUSIONS: Our regression model provides increased specificity of CDUS for high-grade stenosis in patients who have met initial highly sensitive screening criteria. Application of this model may limit the need for additional imaging and increase the threshold for operative intervention in asymptomatic patients with equivocal high-grade carotid stenosis.