Low-dose CT: A safe and effective imaging modality in post-operative pelvic & acetabular fixation.

INTRODUCTION: Post-operative pelvic & acetabular fixation patients are conventionally imaged using 3-view radiographs (AP, inlet and outlet). The efficacy of such radiographs is inconsistent due to technical difficulties capturing an adequate view, often necessitating repeat radiographs and therefore increasing radiation exposure. Radiographs can be difficult to interpret, limiting the assessment of fracture reduction and fixation, especially with respect to metalwork positioning around articular surfaces. Traditionally, post-operative pelvic & acetabular fixation patients undergo repeat 3-view radiographs post-operatively, at 6 weeks, followed by at 3, 6, 12, 18 and 24 months. We propose a new pathway, in which patients have one low-dose pelvic CT immediately post-operatively, followed by one radiograph (AP pelvis) at the same time points. METHODS: A new pelvic CT protocol was created to provide high quality 3D imaging whilst delivering a 5 times lower radiation dose (compared to normal pelvic CT). Data for all pelvic radiographs and CTs between January 2021 and March 2022 was exported. Using dose area product values, effective radiation dose and attributable lifetime cancer risk were calculated. RESULTS: There were 42 patients included in the analysis (age range 15 to 87).The average effective dose for the 3-view pelvic X-rays was 0.6mSv (range 0.2 to 2.8mSv), and 1.1mSv (range 0.5 to 2.2mSv) for the low-dose pelvic CT. Traditional 7 × 3-view post-operative radiographs: 7 × 0.6mSv = 4.2mSv (corresponding to 1 in 11,000 cancer risk) Low dose post-operative CT and 6 × 1-view radiographs: 1.1mSv + (6 × 0.6mSv / 3) = 2.3mSv (corresponding to 1 in 20,000 cancer risk) CONCLUSION: Low-dose CT scanning (in conjunction with 1-view radiographs) is an effective and safe imaging modality in the post-operative assessment of pelvic & acetabular fracture fixation, conferring a lower radiation burden, easier logistics, and higher quality images when compared to the traditional pathway of 3-view radiographs.

Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model.

INTRODUCTION: Lumbar spinal stenosis is degenerative narrowing of the spinal canal and/or intervertebral foramen causing compression of the spinal cord and nerve roots. Traditional decompression techniques can often cause significant trauma and vertebral instability. This paper evaluates a method of increasing pedicle length to decompress the spinal and intervertebral foramen, which could be done minimally invasive. METHODS: Three Sawbone (Sawbones Europe, Sweden) and 1 cadaveric lumbar spine underwent bilateral pedicle distraction at L4. A pedicle channel was drilled between the superior articular process and transverse process into the vertebral body. The pedicles underwent osteotomy at the midpoint. Screws were inserted bilaterally and fixated distraction of 0 mm, 2 mm, 4 mm and 6 mm. CT images were taken at each level of distraction. Foramen area was measured in the sagittal plane at L3/4. Spinal canal area was measured at L4 in the axial images. The cadaver was used to evaluate safety of osteotomy and soft tissue interactions preventing distraction. Statistical analysis was by student paired t-test and Pearson rank test. RESULTS: Increasing distraction led to greater Spinal canal area. From 4.27 cm2 to 5.72 cm2 (p = 0.002) with 6 mm distraction. A Maximal increase of 34.1%. Vertebral foramen area also increased with increasing pedicle distraction. From 2.43 cm2 to 3.22 cm2 (p = 0.022) with 6 mm distraction. A maximal increase of 32.3%. The cadaver spinal canal increased in area by 21.7%. The vertebral foramen increased in area by 36.2% (left) and 22.6% (right). DISCUSSION: For each increase in pedicle distraction the area of the spinal and vertebral foramen increases. Pedicle distraction could potentially be used to alleviate spinal stenosis and root impingement. A potential osteotomy plane could be at the midpoint of the pedicle with minimal risk to nerve roots and soft tissue restrictions to prevent distraction.

Transvaginal ultrasound-guided aspiration of an anterior sacral meningocele masquerading as a hydrosalpinx, resulting in abscess formation.

Anterior sacral meningoceles (ASMs) have a recognized association with a number of connective tissue disorders, including Marfan's syndrome, neurofibromatosis Type 1 and Ehlers-Danlos syndrome. We present the case of a patient with Marfan's syndrome and ASMs who was referred to gynaecology owing to dysmenorrhoea and left-sided pelvic pain radiating to the left leg. A transvaginal ultrasound scan (TVUS) detected a left pelvic cystic tubular structure, attributed to a hydrosalpinx, which, in retrospect, likely corresponded to the ASM. The patient went on to have TVUS-guided drainage of this cystic structure, resulting in an ASM abscess. It is difficult to distinguish ASM from the vastly more common hydrosalpinx using TVUS alone, and in patients with an atypical appearing posteriorly positioned cystic pelvic lesion or in the presence of underlying conditions known to be associated with ASMs, MRI should be considered before any interventional procedure to drain the suspected hydrosalpinx transvaginally. The patient was successfully treated using a minimally invasive CT-guided posterior trans-sacral drainage technique.

Thoracic disc prolapse presenting with abdominal pain: case report and review of the literature.

We report the case of a patient presenting with abdominal pain as a result of a thoracic disc prolapse. The literature is reviewed, highlighting the associated morbidity by the often extensive and invasive procedures patients may undergo when a thoracic disc prolapse presents with abdominal pain.

Arterio-ureteric fistula following iliac angioplasty.

Arterio-ureteric fistulae are rare but can be associated with significant morbidity and mortality. We describe a novel case in which an arterio-ureteric fistula occurred as a complication following external iliac artery angioplasty and stenting, in a patient who had undergone previous pelvic surgery, radiotherapy, ureteric stenting, and urinary diversion surgery. Prompt recognition enabled successful endovascular management using a covered stent.