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Approach to the Critical Patient
Immediate priorities
Triage and stabilization
Pelvic hemorrhage risk with high-energy pelvic ring mechanism
If shock or pelvic instability, pelvic binder centered over greater trochanters
If ongoing instability or bleeding, trauma surgery and interventional radiology activation
Neurologic emergency screening
If urinary retention, overflow incontinence, saddle anesthesia, progressive leg weakness, urgent cauda equina pathway
If new bowel incontinence, urgent spine surgery consultation
Open injury pathway
If open wound near sacrum or perineum, open fracture protocol
If gross contamination, broaden antibiotics and urgent operative washout planning
High-risk associated injuries
Pelvic ring injury coexistence
If posterior pelvic pain with instability, treat as pelvic ring until proven otherwise
If unable to mobilize or severe pain, CT pelvis priority
Urogenital injury risk
If blood at meatus or perineal ecchymosis, urethral injury precautions
If gross hematuria, bladder injury evaluation
Limb threat and neurovascular documentation
Neurovascular baseline and repeat checks
Lower extremity pulses
Dorsalis pedis pulse
Posterior tibial pulse
Motor and sensory domains
L4 knee extension
L5 great toe extension
S1 plantarflexion
S2-S4 perianal sensation
Documentation timepoints
Pre-immobilization baseline
Post-analgesia and after any repositioning
History
Mechanism and timeline
Injury context
Mechanism category
High-energy trauma
Low-energy fall
Repetitive stress
Impact pattern
Direct blow to buttocks
Axial load through spine
Time course
Time since injury
Pain trajectory over time
Red flags and functional impact
Neurologic and pelvic organ symptoms
Cauda equina features
Urinary retention
Saddle anesthesia
New bowel dysfunction
Radicular symptoms
Sciatica pattern pain
New numbness or weakness
Functional limitation
Ability to ambulate
Pain with sitting
Risk modifiers
Bone health risks
Osteoporosis or fragility fracture history
Chronic glucocorticoids
Bleeding risk
Anticoagulants
Platelet dysfunction or liver disease
Physical Exam
General and pelvic stability
Global assessment
Vital signs and shock indicators
Persistent tachycardia
Hypotension
Pelvic stability precautions
Avoid repeated pelvic compression maneuvers
Binder position check over greater trochanters
Inspection and palpation
Skin and soft tissue
Ecchymosis over sacrum or perineum
Laceration near sacrum or perianal region
Tenderness localization
Midline sacral tenderness
Coccygeal point tenderness
Neurologic and rectal focused exam
Lumbosacral neurologic exam
Motor testing
Hip flexion
Knee extension
Ankle dorsiflexion
Great toe extension
Sensory testing
L4 medial leg
L5 dorsum foot
S1 lateral foot
S2-S4 perianal sensation
Pelvic floor screening
Rectal exam indicators
If cauda equina concern, anal tone
If open injury concern, gross blood
Bladder distention clues
Suprapubic fullness
Inability to void
PITFALLS
Common misses
Normal radiograph does not exclude sacral fracture
Occult fractures common in older adults and insufficiency patterns
Coccyx pain with normal imaging may still be fracture or dislocation
Management remains symptom-guided
Neurologic deficits can be subtle early
Repeat exams after analgesia and over time
Differential Diagnosis
Traumatic causes
Fracture and dislocation spectrum
Sacral fracture (ICD-10 S32.1)
Denis zone I lateral to foramina
Denis zone II through foramina
Denis zone III central canal
Coccyx fracture (ICD-10 S32.2)
Fracture without dislocation
Fracture with displacement
Coccyx dislocation (ICD-10 S33.2)
Anterior subluxation
Posterior subluxation
Pelvic ring injury (ICD-10 S32.8)
Sacroiliac disruption
Pubic rami fractures
Neurologic emergencies
Cauda equina syndrome (ICD-10 G83.4)
Urinary retention and saddle anesthesia
Progressive bilateral leg symptoms
Non-traumatic and mimics
Insufficiency and stress conditions
Sacral insufficiency fracture
Osteoporosis risk profile
Minimal trauma onset
Stress fracture
Endurance activity
Progressive pain with load
Pain mimics
Lumbar radiculopathy
Dermatomal pain pattern
Positive straight leg raise
Sacroiliac joint dysfunction
Pain provoked by SI maneuvers
Minimal focal bony tenderness
Coccydynia without fracture
Pain with sitting
Normal neuro exam
Laboratory Tests
Trauma and bleeding assessment
Baseline labs when high-energy or admission likely
Complete blood count for occult bleeding
Hemoglobin trend
Leukocytosis interpretation with stress response
Electrolytes and renal function
Sodium mmol/L
Potassium mmol/L
Coagulation studies when anticoagulated or bleeding risk
INR
aPTT
Type and screen when pelvic ring injury or shock concern
Massive transfusion protocol readiness
Crossmatch triggers with ongoing instability
Infection and open injury considerations
Open fracture or contaminated wound labs
Lactate mmol/L in shock concern
Serial trend for resuscitation response
False elevation with seizures or beta agonists
Creatine kinase when crush or prolonged immobilization concern
Rhabdomyolysis risk
Renal protection planning
Diagnostic Tests
Scoring Systems
Sacral fracture classification
Denis zones
Zone I typically lower neurologic risk
Zone II higher nerve root risk
Zone III highest central canal risk
AO Spine sacral classification
Morphology guides stability and operative planning
Neurologic status modifiers for urgency
Pelvic ring stability context
Stable patterns
Isolated coccyx fracture or dislocation
Isolated low-energy nondisplaced sacral fracture
Unstable patterns
Sacral fracture with pelvic ring disruption
Displacement or vertical shear features
Radiographs
Initial radiographs
Pelvis radiograph
Anteroposterior pelvis
Inlet and outlet views if pelvic ring concern
Sacrum and coccyx views when available
Lateral sacrum and coccyx
Limited sensitivity for nondisplaced fractures
Post-intervention imaging
After any reduction attempt of coccygeal dislocation
Lateral view alignment check
Symptom response correlation
MRI
Indications
Suspected sacral insufficiency fracture with negative CT or radiograph
Bone marrow edema confirmation
Multilevel stress injury mapping
Neurologic deficit or cauda equina concern
Canal compromise evaluation
Nerve root compression localization
Limitations
Availability constraints in unstable trauma
CT preferred in acute trauma workflow
MRI after stabilization for persistent deficits
CT
Primary advanced imaging in trauma
CT pelvis with multiplanar reconstructions
Posterior ring and sacral ala detail
Foraminal and canal involvement assessment
Indications despite normal radiographs
Focal sacral tenderness with high-energy mechanism
Inability to mobilize with persistent pain
Surgical planning value
Displacement quantification
Canal compromise degree
Sacroiliac joint extension
Associated injury evaluation
Pelvic hematoma
Acetabular involvement
Disposition
Discharge criteria
Low-risk outpatient pathway
Hemodynamic stability
No shock indicators
No transfusion requirement
Neurologic stability
No new weakness
Normal perianal sensation
Mobility and pain control
Ambulation with assistive device if needed
Oral analgesia adequate
Admission and transfer criteria
Admission indications
Uncontrolled pain preventing mobilization
Inadequate outpatient function
Need for inpatient physiotherapy
Neurologic deficit
Progressive symptoms
Suspected cauda equina
High-energy pelvic trauma
Polytrauma observation
Need for serial exams
Transfer or urgent specialty involvement
Spine or orthopedic trauma consultation triggers
Displaced sacral fracture
Denis zone III involvement
Trauma center criteria
Pelvic ring instability
Hemodynamic instability or transfusion need
Treatment
Immediate life-saving interventions
Resuscitation and hemorrhage control
Pelvic stabilization when ring injury suspected
Pelvic binder over greater trochanters
Minimize logrolling and pelvic manipulation
Massive hemorrhage pathway when indicated
Balanced transfusion strategy
Interventional radiology for arterial bleeding when available
Neurologic emergency escalation
If cauda equina concern, emergent spine surgery consultation
Bladder scan and catheterization for retention
MRI priority after stabilization
Immobilization and Splinting
Activity modification and positioning
Weight-bearing status
As tolerated for nondisplaced stable fractures
Protected weight-bearing for painful insufficiency fractures
Sitting pressure reduction
Donut or wedge cushion for coccygeal pain
Side-lying rest during peak pain
Mobility aids
Assist devices
Walker for frailty or severe pain
Crutches for younger ambulatory patients
Fall prevention
Home safety planning
Early physiotherapy referral when available
Reduction
Coccyx dislocation reduction considerations
Indications
Severe deformity with refractory pain
Failure of conservative measures with clear dislocation
Contraindications and caution triggers
Open perineal wound
Suspected pelvic ring instability
Analgesia and anesthesia options
Non-opioid baseline
Acetaminophen 1000 mg PO every 6 hours
Ibuprofen 400 mg PO every 6 to 8 hours with food
Opioid rescue when needed
Hydromorphone 1 to 2 mg PO every 4 to 6 hours as needed
Oxycodone 5 mg PO every 4 to 6 hours as needed
Procedural sedation if required
Monitoring requirements
Continuous pulse oximetry
Continuous ECG
Capnography when available
Medication options
Ketamine IV 1 mg/kg
Additional 0.25 to 0.5 mg/kg IV as needed
Emergence mitigation with quiet environment
Propofol IV 1 mg/kg
Titration 0.5 mg/kg every 1 to 3 minutes
Hypotension and apnea readiness
Reduction technique principles
Gentle sustained manipulation with adequate analgesia
Avoid repeated forceful attempts
Immediate symptom reassessment
Post-reduction requirements
Neuro exam repeat
Lateral radiograph confirmation when feasible
Open fracture medications and timing
Antibiotics and tetanus
Timing principle
IV antibiotics as early as possible when open fracture suspected
Do not delay for imaging when wound clearly open
Antibiotic selection examples
Cefazolin 2 g IV every 8 hours
If severe beta-lactam allergy, clindamycin 900 mg IV every 8 hours
Heavily contaminated wounds
Add gram-negative coverage per local protocol
Early operative washout planning
Tetanus prophylaxis
Tdap booster if not up to date
Tetanus immune globulin if unknown or incomplete immunization and dirty wound
DVT prophylaxis when relevant
Risk-based prophylaxis
Elevated risk scenarios
Pelvic ring injury
Prolonged immobility
Pharmacologic options when not contraindicated
Enoxaparin 40 mg subcutaneous daily
Dose adjustment for renal impairment per local protocol
Mechanical options
Intermittent pneumatic compression
Early mobilization emphasis
Special Populations
Pregnancy
Imaging and analgesia considerations
Radiation minimization
CT when needed for maternal stabilization
Shielding when feasible without compromising image quality
Medication safety
Acetaminophen preferred baseline analgesic
NSAID avoidance in later pregnancy per obstetric guidance
Obstetric coordination
Fetal monitoring when viable gestation and significant trauma
Rh immune globulin when indicated
Geriatric
Insufficiency fracture pathway
High suspicion despite normal radiographs
Early CT or MRI consideration
Osteoporosis evaluation and treatment referral
Pain and delirium risk mitigation
Opioid minimization strategies
Bowel regimen initiation when opioids used
Disposition threshold
Admission for mobility failure
Inpatient physiotherapy and discharge planning
Social supports assessment
Pediatrics
Pediatric coccyx and sacral injury nuances
Low incidence of true fractures
Contusion and soft tissue pain common
Imaging reserved for concerning mechanism or neuro symptoms
Safeguarding considerations
Non-accidental trauma consideration when history inconsistent
Multidisciplinary involvement when indicated
Background
Epidemiology
Population patterns
Sacral fractures often associated with pelvic ring injury in high-energy trauma
Higher risk of hemorrhage with unstable pelvic patterns
Higher risk of neurologic injury with central canal involvement
Sacral insufficiency fractures in older adults
Osteoporosis association
Often occult on radiographs
Coccyx injury characteristics
Coccydynia commonly post-fall onto buttocks
Imaging frequently normal
Management primarily conservative
Pathophysiology
Mechanism to pattern mapping
Axial load
Vertical sacral fractures
Posterior ring instability potential
Direct impact
Coccyx fracture or dislocation
Local periosteal pain generator
Neurologic injury mechanisms
Foraminal involvement
Nerve root irritation
Radicular pain patterns
Canal involvement
Cauda equina compression risk
Bladder and bowel dysfunction risk
Therapeutic Considerations
Nonoperative management rationale
Stable nondisplaced fractures
Pain control and mobilization as tolerated
Avoid prolonged bedrest when possible
Coccyx injury management
Cushioning reduces focal pressure
Stool softeners reduce pain with defecation
Operative or urgent specialty rationale
Displaced sacral fractures
Stability restoration for mobilization
Reduction of neurologic compromise risk
Progressive neurologic deficits
Decompression and stabilization considerations
Time sensitivity in cauda equina pathways
Patient Discharge Instructions
Copy discharge instructions
Home care and activity
Relative rest
Avoid prolonged sitting on hard surfaces
Gradual return to activity as pain allows
Cushioning
Donut or wedge cushion for sitting
Side-lying rest breaks
Mobility
Weight-bearing as tolerated unless told otherwise
Use walker or crutches if needed for safety
Pain plan
Acetaminophen 1000 mg PO every 6 hours as needed
Ibuprofen 400 mg PO every 6 to 8 hours as needed with food
If opioid prescribed
No driving or alcohol
Constipation prevention plan
Bowel care
Polyethylene glycol 17 g PO daily while on opioids
Senna 8.6 mg 1 to 2 tablets PO at bedtime while on opioids
Return to emergency criteria
New weakness in legs
Numbness around groin or anus
Trouble starting urination or inability to urinate
New bowel incontinence
Increasing severe pain not controlled with medication
Fever or wound drainage if skin break present
Follow-up plan
Stable coccyx injury
Primary care or sports medicine follow-up in 1 to 2 weeks if persistent pain
Consider physiotherapy if ongoing symptoms
Sacral fracture
Orthopedics or spine follow-up in 1 to 2 weeks based on stability and imaging
Earlier follow-up if neurologic symptoms present
References
Guidelines and core references
Trauma and resuscitation standards
ATLS principles for pelvic trauma evaluation and hemorrhage management
Pelvic binder use in suspected unstable pelvic ring injuries
Orthopedic and spine references
Denis sacral fracture classification framework
AO Spine sacral classification framework
Procedural sedation references
ACEP procedural sedation clinical policy evidence levels for ED sedation
Monitoring standards including capnography when available
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.