Pelvic, spinal & sacrococcygeal fractures & luxations Flashcards
(28 cards)
1
Q
Pelvic fractures - initial assessment
A
- these are severe injuries
- assessment of the whole animal is essential
- airway, breathing and circulation
- additional assessment includes D-disability e.g. mentation and E-external injuries e.g. visible sites of haemorrhage
- radiograph or TFAST/POCUS chest
- determine integrity of urinary tract (contrast radiography or US)
- neuro deficits particularly with sacrococcygeal luxation (tail-pull injury) in the cat with UMN or LMN deficits resulting in spastic or atonic bladder
- finally radiograph the pelvis, remember it is a box like structure therefore a single fracture/luxation cannot occur in isolation
2
Q
Pelvic fractures - management options
A
Conservative mangement
- less invasive
- less expensive
- outcome less predictable (poorer?)
- recovery more prolonged
Surgical management
- invasive and expensive
- but likely to provide more rapid and fuller return to function
- rapid pain relief
- potentially better outcomes
3
Q
Pelvic fractures - factors to consider before deciding tx/management
A
- is the pt ambulatory?
- how long has the fracture been present?
- is the weight-bearing axis involved?
- is the acetabulum involved?
- is the pelvic canal diameter reduced (<50%)?
- is the pt intractably painful?
- are there multiple problems e.g. limb fractures?
- the presence of neuro deficits (e.g. bladder function) can affect the decisions made re fracture repair (argument that neuro deficits should be dealt with surgically i.e. surgical repair of the fracture)
4
Q
When does manipulation of a fracture become more difficult (re after the traumatic event)?
A
- 5d after the traumatic event
5
Q
What can happen if the pelvic diameter is reduced (<50%) and left in that state?
A
- chronic constipation or dystocia in the intact female may result
6
Q
As a general principle, what fractures are operated on?
A
- ilial
- acetabular
- bilateral
7
Q
Pelvic fractures affecting the weight bearing axis involve which structures?
A
- ilial shaft and wing
- iliosacral articulation
- acetabulum
8
Q
Pelvic fractures: sacral fracture and sacroiliac luxation - causes, signs
A
- RTA ‘shunting injury’ (animal is struck from the rear)
- these injuries may be stable
- they can be bilateral
- often accompanied by neurological abnormalities including sciatic neuropathies and urinary incontinence
- can be very painful particularly if there’s bilateral sacroiliac luxation
- always look for other pelvic fractures
9
Q
Pelvic fractures: sacral fracture and sacroiliac luxation - which nerve tends to get damaged?
A
- sciatic
10
Q
Pelvic fractures: sacral fracture and sacroiliac luxation - tx
A
Can be managed conservatively if greater than 50% of articular surfaces are in contact.
Surgical management can be difficult and is prone to error including failure to engage the body of the sacrum in lag screw fixation or entering the neural canal with catastrophic consequences
Options include
- large lag screw ± anti-rotational wire
— should engage at least 60% of the width of the sacral body
— in larger dogs 2 shorter screws have been shown to be stronger than the single longer screw
- trans-ilial pin if 1 of the hemipelvis’ is intact
— not overly stable
11
Q
Pelvic fractures: ilial shaft fractures - characteristics, tx
A
- usually long oblique fractures
- caudal fragment often displaces medially narrowing the pelvic canal diameter
- well contoured plate with preferentially 1 or 2 screws in the body of the sacrum. ideally engage 6 cortices either side of the fracture
- a long oblique fracture can be managed with lag screws alone
- the pelvis is inherently stable and therefore very rigid repair is not always necessary
12
Q
Pelvic fractures: ilial shaft fractures - complications
A
- reduction can be difficult esp if the injury is chronic (greater than 5d/o)
- iatrogenic damage to the sciatic nerve is a real risk (it runs over the ilial shaft and can get trapped in the fracture site)
- management of these fractures requires considerable experience
- can be v difficult to reduce these fractures in larger dogs
13
Q
Pelvic fractures: acetabular fractures: tx options & considerations
A
- weight bearing is mainly on the dorsocranial acetabulum in the dog but mid region? in the cat (now thought that cat bears weight similarly to the dog and the whole articular surface is important)
- failing to reconstruct fractures of the caudal 3rd can result in poor outcomes despite apparent reduced weight bearing in this area (e.g. OA)
- these can be difficult fractures to repair to always give option to refer
- comminution of the medial wall is particularly difficult to manage
Most common methods
- plate fixation (acetabular plate, standard or locking plate or reconstruction plates)
- mid-acetabulum: screws, wires and methylmethacrylate composite
- if complex or cost issues then a FHNE can be adopted but wait to see what function is gained with a conservative approach before performing this surgery
14
Q
Pelvic fractures: pubic fractures - when to be concerned, what to do?
A
- may be of little concern unless they’re associated with rupture or loss of the pre-pubic tendon and a ventral hernia
- bladder incarceration can occur in this hernia
- generally pubic fractures require no tx and the pre-pubic rupture occurs with an intact pubis
15
Q
Spinal fractures - cause & signs
A
- uncommon
- subluxation commonly accompanies these fractures
- generally occur with RTAs but can occur as a result of pathologies such as infection or neoplasia
- often associated with neuro deficits
- are very painful
- are potentially life-threatening
- tend to occur where a more rigid section of the spine meets a more flexible area (e.g. T/L junction [the most common site], L/S junction and C spine)
- given these factors an early referral should be offered
16
Q
Spinal fractures - initial management
A
- these pts are unstable
- the usually approach is applied to these trauma cases: ABC
- careful palpation may reveal the site of spinal instability
- if these pts are showing obvious nerve deficits e.g. no tone in hindlimb or tail, or the Schiff Sherrington posture with no hindlimb tone and hyperextended forelimbs then assume there is severe spinal trauma
- support the back at all times
- the use of a rigid carrying board upon which the pt can be strapped is v useful
- give analgesia but avoid analgesia or deep sedation unless absolutely necessary as the muscle spasm and tone provide local support over the fracture site
- radiograph the spine at 1st opportunity
17
Q
Spinal fractures - neuro evaluation
A
- try to localise the site of any potential fracture/luxation
- assess tone in fore, hindlimb and tail
- where is the most marked muscle spasm?
- is there a cut off of the panniculus/cutaneous trunk reflex
- is there a perineal reflex?
- is the pt showing a Schiff-Sherrington posture suggestive of cord transection between the fore and hindlimb (flexed forelimbs, flaccid and no pain/sensation associated with the hindlimbs)
- most importantly: is there conscious pain perception (nociception) on applying painful stimuli to the hindlimb or tail if T/L lesion, or hindlimbs, forelimbs and tail if cervical
– this means that the animal looks round or vocalises when a painful stimulus is applied not that it just withdraws the limb
– this is the single most important factor that determines the likelihood of recovery from a spinal injury
– initially there may be reduced reflexes/responses due to spinal shock but these return within 30mins of trauma to the dog - if there is no deep pain sensation the prognosis for the animal is poor
18
Q
Spinal fractures - radiographic evaluation
A
- simple lateral views taken of the conscious animal maybe all that is required to determine the nature and significance of the injury
– but it is important to appreciate that the final position of the vertebrae may not reflect their position at the time of the trauma - orthogonal views can be useful but may be difficult to achieve in the non-anaesthetised animal
- perform a spinal surgery to avoid missing multiple fractures
- myelography is rarely helpful
- a markedly overridden fracture in a deep pain negative dog carries a hopeless prognosis
19
Q
Spinal fractures - use of MRI & CT
A
- CT is very useful particularly if surgical management is contemplated
– it allows 3D reconstructions
– forgiving of malpositioning which can be unavoidable but does require either deep sedation or GA - MRI gives information about the cord but the image acquisition time is long
20
Q
Spinal fractures - importance of fracture site
A
- lower lumbar region surrounds the cauda equina (nerves rather than the cord which are much more resistant to trauma)
- the cervical region has much greater space within the spinal canal allowing the cord greater movement without being compressed
- injuries involving the sacrum maybe more significant because of their effect on urinary and faecal continence
21
Q
Spinal fractures - pathophysiology/biomechanics
A
- the site of the fracture within the vertebral/intervertebral disc unit is important in determining the degree of stability likely associated with the fracture
– generally a 3 compartment model is used: dorsal component, middle component, ventral component - the dorsal component includes the spinous processes, articular facets and joints dorsal lamina and lateral pedicles and the soft tissue structures that connect these
- the middle component is the dorsal longitudinal ligament, dorsal disc (annulus fibrosis) and dorsal part of the vertebral body i.e. the floor of the vertebral column
- the ventral component is the ventral part o the disc (the ventral annulus and nucleus pulposus) and the ventral 1/2 of the vertebral body and ventral longitudinal ligament
- if more than 1 of these components is damaged then the fracture is deemed unstable
- the decision as to whether to perform sx is based on the combination of neurological status and the degree of instability at the fracture/luxation site and its position
- the spinal cord is exposed to similar forces as long bone fractures i.e. bending, axial compression, torsion and shear
- all ^ these need to be addressed in managing the fracture
- generally vertebral body fractures create great instability
- loss of the intervertebral disc creates rotational instability
- articular facet fracture, even if bilateral, creates little instability
22
Q
Spinal fractures - conservative management
A
- relatively stable fractures and those occurring in the lumbosacral region can be managed conservatively
- this consists of cage rest for 6-8w or external splints
- management of splints is difficult and this form of immobilisation can’t be recommended
- cats won’t tolerate external splints but are amenable to cage rest
- careful nursing is required particularly to avoid urine scalding and decubitus ulcers
- appropriate analgesia should be provided at all times
23
Q
Spinal fractures - surgical management
A
- various methods are available to treat these fractures
- if there is significant cord compression then a hemilaminectomy may need to be performed
– this takes out the dorsolateral wall of the vertebral canal and allows blood clots and bone fragments to be removed and the cord decompressed - in the cervical region pins and methacrylate bridges are the most versatile form of fixation -> these are placed ventral to the vertebrae
– this technique can also be performed dorsally in the thoracolumbar region but plating with either a standard dynamic compression plates or locking plates can also be employed at this site - a Lubra plate can be used to align the vertebrae by gripping consecutive spinal processes
– this is not a very strong type of fixation
24
Q
Spinal fractures - prognosis
A
- good if conscious nociception is preserved
- if this is not the case then the prognosis is poor and O need to be aware of this prior to the instigation of any tx
- irrespective of whether a conservative or surgical management option is adopted careful nursing particularly of the urinary system is essential and catheterisation with a closed collecting system is very helpful
- during the period of cage confinement it is essential to provide sensory stimuli for the pt
- rehab with physiotherapy is also important
25
Sacrococcygeal luxations - cause, presentation
- common injuries in the cat following an RTA
- present with a flaccid tail, urinary retention or occasionally a flaccid bladder and overflow
- these cases can present with a grossly distended bladder if the O was unaware of the original injury
- on occasions the cat might show concurrent mild sciatic neuropathy due to involvement of this nerve
- examine the cat for other injuries e.g. scuffed nails suggestive of RTA and breathing difficulties
26
Sacrococcygeal luxations - diagnosis
- usually fairly straight forward
- distended bladder and flaccid tail with no or little sensation
- the luxation may be palpable as a depression at the base of the tail
- radiographic diagnosis although it is important to appreciate that the degree of displacement of the coccygeal vertebrae doesn't reflect the severity of the resulting neurological deficits
- always radiograph the chest and pelvis to detect concurrent injuries
27
Sacrococcygeal luxations - tx
- conservative management with manual expressing of the bladder and meds to encourage micturition
- bethanachol to increase detrusor tone
- phenoxybenzamine or prazosin to reduce striated muscle tone and dantrolene to reduce smooth muscle tone in the urethra
- the O can be taught how to express the bladder at home
- if this were to prove impossible and drug therapy fails a temporary cystotomy tube can be placed
- some advocate early amputation of the tail to reduce the traction on the pelvic nerves esp if widely luxated
- there are reports of reattaching the coccygeal vertebrae to the sacrum and improved recoveries as a result but this has not been established
28
Sacrococcygeal luxations - prognosis
- good to fair but if there is no improvement after 4w the prognosis worsens
- cats with deep pain sensation intact at the tail base within 24h of their injury have a better long term outlook and have been reported to regain bladder control within 3d of this finding
