Category Archives: Spine

Mimicker: Inguinal Mesh Plug

Depending on the inguinal hernia repair method chosen, a mesh plug can be used for reinforcement. One such method uses a polypropylene (Prolene) plug

    • The post-operative appearance of an inguinal mesh plug can masquerade as an inguinal mass or lymphadenopathy

Imaging Findings

    • On CT, mesh plugs can have a slightly nodular or smooth outline. The density is similar to sightly lower than muscle. Mesh plugs have also been reported as a ring-like density with central fat attenuation, potentially mimicking epiploic appendicitis if on the left
    • On MRI, mesh plugs are typically T1 hypointense and demonstrate variable T2 weighted signal
    • Due to a granulomatous reaction, mesh plugs can be FDG avid

Helpful hints in preventing misdiagnosis

    • Mutliplanar reformations can be useful in demonstrating the conical morphology of the mesh plug, although they can appear ovoid
    • Postsurgical changes including skin thickening and suceptabliity artifact can also be helpful imaging features
Ryan Schwope mesh plug
Left inguinal mesh plug with a lobular contour
Ryan Schwope mesh plug cor
Left inguinal mesh plug. Note conical morphology on this coronal MPR.


The British Journal of Radiology, 77 (2004), 261–265
J Comput Assist Tomagr. 2008Jul-Aug;32(4):529-32.
American Journal of Roentgenology. 2010;195: 701-706.

Suspected Type I Rotatory Atlatoaxial Subluxation in Asymptomatic Patients

type I Atlantoaxial Rotatory Subluxation

In an earlier post on rotatory atlatoaxial subluxation, we discussed the Fielding and Hawkins classification, and its application to symptomatic patients (e.g., those with torticollis). Here, we discuss the challenge of making a diagnosis of rotatory atlatoaxial subluxation in unselected patients.

That is, what do you do if your neck or c-spine CT scan is obtained with the head turned, and you see what looks like a Type I rotatory atlatoaxial subluxation?

The patient below was referred to our institution in a cervical collar for management of atlantoaxial rotatory subluxation.

normal head rotation

30-year-old man: Thick reconstructions centered at C1-C2 from a CTA obtained with the head rotated to the left. There is apparent type I atlantoaxial rotatory subluxation.


Let’s take a look at what we know:

  • Normal maximum rotation of the head on body is between 60–80°.
  • Normal maximum rotation of C1 on C2 makes up for about half of that: 30–45° (although some sources say it can be up to 50°).
  • Cutoff for abnormal C1-C2 rotation: >45° or >56°, depending on source.

Looking at our image above, our rotation of C1 on C2 is about 30 degrees, which puts it in the normal range. But, what if the number was higher? How well do we do as radiologists in correctly identifying this as normal?

One study that was helpful came from the forensic field. Pathologists had noted that CTs of cadavers, which are impossible to position “correctly,” were resulting in a lot of over-calling of atlantoaxial rotatory subluxation. When they looked at their data they found:

  • 19 cases where the C-spine was stable on autopsy. In those 19, 13 had suspected rotatory subluxation based on on CT (false positives)
  • The C1-C2 angle in those 13 false positives were between 16–47°.
  • All false positives were type I.
  • 2 cases where the C-spine was unstable at autopsy. In those 2 cases, 1 had suspected rotatory subluxation on CT (true positive).
  • The C1-C2 angle in the 1 true positive was 42°.
  • There was a significant association between the false positives and degree of head rotation.

Generalizing this cadaveric study suggests that we need to be careful in calling type I atlantoaxial rotatory subluxation in asymptomatic patients who simply happen to have their head turned in the scanner. This supports the conclusions from a study in living, asymptomatic patients, where the authors showed that incomplete rotational facet displacement on CT was not sufficient to define subluxation.


Endologix Stent-graft


Most endostent devices used for endovascular repair of aortic aneurysms have the graft material sutured on the luminal side of the stent. The AFX endostent device (Endologix, Irvine, California) is different from other devices in that the graft material is sutured on the outside of the metal component, attached only at the proximal and distal ends.

Delayed CT shows the smoothly marginated contrast extending beyond the confines of the metal strut Ryan Schwopeunchanged in size and configuration when compared to arterial phase imaging


By intent, the graft material of the AFX stent-graft can separate from the metal struts where it is not directly apposed to the aortic wall.  During surveillance with contrast-enhanced imaging of patients who have reviewed this device, contrast can be detected outside of the metallic construct. Although this finding can imply a type 1 or 3 endoleak when identified with other endostents, it is a normal finding with the AFX device.

Avoiding misinterpretation as an endoleak can be achieved by confirmation of the type of endostent device used for aneurysm repair. In addition, the contrast extending beyond the metal struts does not change in configuration or size on delayed imaging.


J Vasc Interv Radiol. 2012 Nov;23(11):1544-6.

Management of Pancreatic Cystic Lesions

Thick slab MRCP image showing massive dilatation of the main pancreatic duct

Incidental cystic pancreatic lesions found on 13% of MRI abdomens

    • Wide variety of pathology both benign and malignant


  • Imaging findings and demographics are the key to diagnosis
Ryan Schwope


Cystic Pancreatic Neoplasms (Four major categories)


    1. Serous cystadenoma: Benign (very low malignant potential)


    1. Mucinous cystic neoplasm (MCN): Premalignant or malignant


    1. Intraductal papillary mucinous neoplasm (IPMN): Malignant potential (Main Duct >> Branch Duct)


    1. Unusual cystic neoplasms:
        • Solid pseudopapillary neoplasm (SPN): Low grade malignancy
        • Cystic forms of more common neoplasms (neuroendocrine)


Nonneoplastic Pancreatic Cysts


    • Pseudocyst


    • Retention cyst


    • Lymphoepithelial cyst


    • Localized ductectasia


Major Imaging Features Guiding Management


    • Number and size of cystic components: Risk of malignancy increases when size ≥ 3 cm


    • Septations and solid components: Mural nodule has a 87% Sp and 56% Sn for malignancy


    • Main pancreatic duct (MPD) dilatation and communication with the cystic lesion: MPD > 10 mm has a 77% Sp and 67-92% Sn for malignancy


Sendai Criteria

High Risk Stigmata

    • Jaundice


    • MPD ≥ 10 mm


    • Enhancing solid component

Worrisome Features

    • Size ≥ 3 cm


    • MPD 5-9 mm


    • Non-enhancing mural nodules


    • Thick enhancing cystic wall


    • Lymphadenopathy


    • Abrupt Duct Termination




    • Any worrisome features present = Endoscopic Ultrasound (EUS) and Cyst aspiration with fluid analysis


    • Any high risk stigmata present or suspicious cytology on EUS = Surgical resection


    • MCN or SPN = Surgical resection


    • Serous cystadenoma
        • 2-3 cm: F/U every 2 years
        • ≥ 4 cm: consider resection


    • IPMN:
        • Main duct and combined type: Surgical resection (but depends on location, pt. age/clinical status)
        • Branch duct type = follow if < 3 cm and contains no solid components
            • If < 2cm F/U q1yr; if growth FU q6mo
            • If 2-3 cm F/U q6mo x 2 years, then q1yr
            • Consider EUS (if mucinous then resect)
            • If growth ≥ 3 cm, resect


What the Clinician/Surgeon wants to know


    1. Number of cystic lesions


    1. Largest cystic lesion
        • Unilocular
        • Multilocular: Microcystic ( 2cm)


    1. Lesion size


    1. Lesion location: Head/Body/Tail


    1. Septations: None/Thin/Thick (> 2mm)


    1. Solid components: Present/Absent


    1. Calcifications: None/Coarse/Rim/Central


    1. Communication with MPD: Present/Absent


    1. Main pancreatic duct diameter: > 5 mm/Not dilated




    • Gandhi NS and Hecht E. “Adding Value to Clinical Care: Structured Reporting of Pancreatic Pathology”, Workshop Session Presentation, Society of Abdominal Radiology Annual Meeting, 2015






Bisphosphonate-related Osteonecrosis of the Jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is associated with the use of bisphosphonates to treat severe osteoporosis, and metabolic and oncologic bone conditions, including hypercalcemia associated with malignancy. These agents inhibit osteoclasts, reducing bone resorption and osteolysis, and also possess antiangiogenic properties, reducing blood flow and necrosis. Patients with BRONJ present with pain and exposed, nonvital bone involving the maxillofacial structures. The incidence of BRONJ increases with the duration of treatment, especially with the intravenous route and concomitant steroid therapy. The osteonecrosis usually is participated by dental extraction. When spontaneous, it commonly occurs along the mylohyoid ridge. BRONJ can mimic osteomyelitis and osteoradionecrosis. A history of dental caries and the presence of periosteal elevation can help direct one towards the diagnosis of osteomyelitis. Osteoradionecrosis can be excluded if the patient has not received oropharyngeal radiation therapy. Jaw neoplasm, primary or metastatic, can potentially also mimic BRONJ. Treatment of BRONJ consists of cessation of bisphosphonate drug therapy, antibiotics for secondary infection, and surgical debridement of necrotic sequestra.

Ryan Schwope BROJN1
Figure 1: Axial CT of the facial bones. There is a mixed sclerotic and lytic lesion within the mandible (Figure 1, arrows) with foci of cortical interruption (Figure 2, arrowheads).
Ryan Schwope BROJN 2
Figure 2: Sagital CT of the facial bones. There is a mixed sclerotic and lytic lesion within the mandible (Figure 1, arrows) with foci of cortical interruption (Figure 2, arrowheads).


Cervical Spine Fracture

The students learned how to treat a femur fracture by using the
The students learned how to treat a femur fracture by using the

Fractures in an extremity are usually remedied by casting and effective surgical and non-surgical treatment options for a full range of cervical and spinal ailments. Dr. Theofilos serves as Chief of Neurosurgery for Palm Beach Gardens Medical Center. The doctor told him that it was now evident that he had sustained multiple avulsion fractures and subluxations of his cervical spine during the brutal 1988 incident. Heathcote was immediately referred to the spinal department at his local hospital. 2 Similarly for lower cervical spine injuries also the literature suggests that in There is also significant disagreement in fracture morphology. This may be due to difficulties in converting from non-uniform, descriptive systems to the current SLIC The study illustrates no cervical plate and screw fractures or screw back outs. There were no cervical non-unions or cervical revisions. The study clearly demonstrates that Eminent Spine’s Copperhead® PEEK cervical cages and the King Cobra® cervical Approximately 5-10% of unconscious patients who present to the ED as the result of a motor vehicle accident or fall have a major injury to the cervical spine. Most Cervical Spine Fractures occur predominantly at 2 levels. One third of injuries occur at the Spinal implants include both fusion and non-fusion devices: devices associated with vertebral compression fracture (VCF), interbody devices, cervical, thoracolumbar, and spinal stimulation devices. Spine industry has witnessed myriad technological .

The vertebral column—the bony spine—is made up of different regions identified as cervical, thoracic suspected extremity fracture or distracting injury, or spine pain/tenderness. As always, the prehospital provider should follow the basic airway The cervical spine is the portion of the spinal column that makes up the neck. According to the University of Southern California (USC) Center for Spinal Surgery, Cervical Spine Fractures are fairly common and, together with cervical spine dislocations A later report from the medical examiner attributed her death to a Cervical Spine Fracture from a fall down the stairs, and cited ethanol intoxication as a contributing factor. Reacting to the situation, Mintz deleted his text messages with Arnett Spinal implants include both fusion and non-fusion devices: devices associated with vertebral compression fracture (VCF), interbody devices, cervical, thoracolumbar, and spinal stimulation devices. Spine industry has witnessed myriad technological .

Another Picture of Cervical Spine Fracture :

C6 C7 Spinal Cord
C6 C7 Spinal Cord Injury

Soft Tissue Swelling
Soft Tissue Swelling