Fractures of the pelvis Flashcards
What concurrent injuries are common following fracture of the pelvis?
Urinary injuries (39%), including ruptured bladder, urethral rupture, urethral avulsion.
Neurologic injury (lumbosacral trunk most commonly affected).
How much pelvic canal narrowing is a concern for obstipation?
45-50%
What is the most common neurologic injury following pelvic fracture?
Injury to the lumbosacral trunk (91% of injuries), with 6% being injuries to the sciatic nerve (the extrapelvic portion of the lumbosacral trunk as the lumbosacral trunk passes over the greater ischiatic notch).
Injuries to the sciatic nerve most common with acetabular or ischial fractures.
15% of patients had permanent loss of limb function.
Why is an oblique radiographic view useful in the work-up of pelvic fractures?
It allows visualization of both acetabula.
Fractures of the pelvis are best repaired within what time-frame?
7-10 days
When should repair of a pubic or ischial fracture be performed?
Pubic: repair may be required in instances of prepubic tendon rupture or avulsion.
Ischium: avulsion fractures of the ischiatic tuberosity may require repair if resulting in persistent lameness (attachment point of the semitendinosus, semimembranosus, adductor muscles).
At what point does exposure of the pelvis functionally end with a gluteal roll-up approach?
The cranial aspect of the acetabulum.
Fractures that extend dorsal to the acetabulum require a lateral approach combined with a dorsal surgical approach to the hip joint.
Why must care be taken when placing bone holding forceps on the ischium for ilial fracture reduction in juvenile patients?
Care must be taken to avoid damaging the soft ischial bone or growth plate.
Traction on the greater trochanter of the femur can be alternatively used for reduction.
What is the tension side of the ilium?
Ventral surface. Lateral plating is most commonly performed, but some authors have suggested using dorsal or ventral plating for improved mechanical stability.
How many cranial and caudal screws are recommended for ilial fracture fixation?
At least 3 screws cranial and 3 screws caudal. The cranial ilium bone stock is very thin. Holding power can be increased by use of a longer plate or placement of screws into the wing of the sacrum.
Failure of neurologic function to improve following pelvic fracture after how many months is associated with a poor prognosis for return to function?
3-4 months
What is an alternative fracture fixation technique to bone plate and screws that might be considered for long oblique fractures of the ilium?
Lag screw fixation
What are the anatomic regions of the acetabulum?
Cranial, dorsal, caudal and central
What is secondary acetabulum protrusion?
Medial luxation of the femoral head into the pelvic canal following acetabular fracture, typically due to central collapse of the acetabulum
Should fractures of the caudal acetabulum be surgical repaired?
Dogs may be ambulatory on presentation, but conservatively managed fractures are associated with poor long-term results due to degenerative joint disease. Therefore repair may be preferred.
How can additional exposure to the caudal acetabulum be achieved following greater trochanteric osteotomy?
Tenotomy of the insertional tendons of the gemelli and internal obturator muscles
What are methods of fixation for an acetabular fracture?
Acetabular plates, straight reconstruction plates, T or L plates, locking plates, screws with washers and/or K-wires with PMMA.
When significant contouring of conventional straight plates is required, plate luting may be considered to improve plate-to-bone contact and maintain acetabular reduction.
What type of surgical repair is shown?
How are widely spaced iliac and acetabular fractures on the same side repaired?
How are iliac and pelvic fractures in close proximity typically repaired?
Combined gluteal roll up and dorsal approach to the hip are required.
Is bilateral or unilateral disease more common with SI luxation?
Unilateral (77% of dogs, 82% of cats)
What nerves might be damaged with SI luxation?
Sacral nerves and lumbosacral trunk. This might result in deficits of the anal sphincter, urinary bladder and sciatic nerve.
What is the typical area available for correct screw placement with SI luxation in a large dog?
1cm squared.
Improper screw positions include ventral to the sacral body, ventral to the sacral body; premature ventral exit of the sacral wing; cranial placement into the intervertebral disc space of L7-S1; and a dorsal position into the spinal canal.
Improper positioning results in a short screw and consequent implant loosening.
Describe the landmarks for screw placement in the sacral wing for SI luxation repair.
Describe the landmarks for screw placement in the ilial wing for SI luxation repair.
What are the two types of observed sacral fracture?
Abaxial: fractures lateral to the sacral foramina as well as fractures of the spinous processes.
Axial: fractures medial to the sacral foramina or ventral to the spinous processes. More likely to involve the spinal canal and be involved with severe neurologic deficits
Alternatively 5 categories of fracture have also been reported: types: I, alar; II, foraminal; III, transverse; IV, avulsion; and V, comminuted.
How are sacral fractures repaired?
Typically with a lag screw(s) (1 or 2) via an open dorsal or fluoroscopic approach.
How can repair of the pubis be performed, if required?
Ventral approach with fixation via interfragmentary wires or small regular or locking bone plates.
How can repair of the ischium be performed, if required?
Ischial body fracture: Dorsolateral approach with stabilization via a small contoured bone plate.
Ischial tuberosity avulsion: lag screws or pin and TBW.
What are the two classification systems for sacral fracture?
Kuntz system: abaxial (lateral to the foraminae) and axial (medial to foraminae) sacral fractures. Axial fractures demonstrate more severe neurologic deficits.
The Anderson type classification system: alar, foraminal, transverse, avulsion and comminuted (see image).
What surgical repair technique was described by Vardanega 2024 in JSAP for repair of sacral fractures?
Transiliac locking plates. Good to excellent outcomes were reported for all cases.
What technique described by Cinti 2020 in VCOT and shown in the image here can be used for widening of the femoral canal in cast with obstipation secondary to fracture malunion? What was the mean pelvic canal enlargement using this approach?
A triple pelvic osteotomy with lag screw fixation.
The mean pelvic canal enlargement was 20%.
No long term complications or obstipation were reported post-operative.
In a study by Lembersky 2022 in VRU, what angle as depicted in the image was associated with sacroiliac luxation?
Angles greater than 2 degrees were associated with sacroiliac luxation (as measured from the wings of the ilium to the cranial endplate of L6).
In a study by Han 2022 in JFMS, what landmarks were described for screw placement in cats with bilateral SI luxation?
In a study by Butts 2023 in JFMS, what radiographic sign could be used to detect subtle slipped capital femoral epiphyses in cats?
The S-sign
