- See:
-
Posterior Pelvic Injury:
-
Sacroiliac Fracture Dislocations:
-
Sacral Stress Fractures:
- Anatomy of Sacrum:
- Classification:
- zone I:
- frx across sacral ala can cause L5 nerve root impingement;
- about 6% of these patients will have
neurological injuries;
- zone II:
- frx thru neuroforamina can cause unilateral sacral anesthesia;
- frx involving the neural foramina require operative debridement of frx fragments prior to reduction and fixation (thru posterior approch);
- zone III
- frx thru body of sacrum can cause highest incidence of injury to
cauda equina and result in neurogenic bladder;
- about 56% of these patients will show
neurological injuries;
- misc:
- transverse fractures;
- U shaped fractures:
- results from axial loading;
- radiographs:
- bilateral transforaminal sacral fractures and irregularities, L5 transverse process frx;
- paradoxic inlet view: on standard AP view, the upper sacrum appears as inlet view;
- ref: Percutaneous stabilization of U shaped sacral fracture using iliosacral screws: technique and early results.
SE Nork et al. JOT. Vol 15. No 4. p 238.
- Associated Injuries:
- if the sacral fracture is impacted w/ no verticle displacement, it may represent a
LC fracture (therefore look for
anterior pelvic injury);
- w/ vertical displacement, the sacral frx may represent a
Malgaine frx equivolent;
- Physical Exam:
- displacement in vertical plane is diagnosed by applying one hand to pelvic iliac crest and using other to apply traction to leg which should
cause displacement in vertical plane;
- Radiology: (see
outlet view);
-
sacral arcuate lines:
- will help delineate anatomy of frx of upper sacrum;
- sacral arcuate lines are composed of inferior surfaces of costal elements that form roofs of anterior sacral canals (foramina) & neural grooves;
- arcuate lines are easily visible on
AP view of pelvis & are symmetrical;
-
asymmetry or discontinuity of sacral arcuate lines may be caused by uncomplicated sacral frx;
-
disorganized or marked disruption of sacral arcuate lines is indicative of comminuted sacral frx;
- CT scan: 
- Determine Frx Stability:
- stable frx includes impacted vertical frx of sacrum, nondisplaced frx of posterior sacroiliac complex; or subtle frx of upper sacrum as seen by
asymmetry of
sacral arcuate lines;
- unstable frx, is characterized by frx diastasis of more than 0.5 to 1 cm, along w/ an unstable
anterior injury;
- the other question, however, is the amount of healing potential;
- if a type I fracture reduces w/ traction, then the unstable frx would be expected to become sticky in about 4 weeks and would expect
complete healing in 3 months;
- Surgical Approach to Fractures of the Sacrum:
- patient is in the prone position on a flouro table;
- similar surgical approach used for posterior approach to the SI joint
- posteror incision is made;
- additional vertical incision is made on opposite side;
- sacral nerve roots & frx site are visualized by placing laminar spreader at frx site or between the two superior ilac crests;
-
decompression:
- decompression of sacral foramina (laminectomy) is helpful for patients w/ neurologic impingment;
-
reduction:
- sacral frx reduction is usually achieved w/ pointed reduction forceps.
- forceps should span from spinous processes of sacrum to iliac crests;
- assess reduction by visualization of posterior sacral lamina & palpation of the fracture through the
greater sciatic notch;
- sacral nerve roots are palpated after the reduction to be certain that they have not been entrapped;
-
fixation:
- obtained w/ one or two screws into S1 vertebral body placed from lateral surface of the iliac wing; (similar to
SI joint dislocation);
- using flouroscopy, insert long 6.5 mm cannulated lag screws engage frx from the iliac wing to the body of S1;
- with transforaminal fractures, use fully threaded screw to avoid compression of the sacral neural foramina
- it may be possible to place a thin malleable plate placed across posterior sacrum from ilium to ilium as a tension band just above
greater sciatic notch;
-
posterior screw fixation:
- it is important to note that malreduction of transforaminal sacral fractures will substantially decrease the space available for iliosacral screws;
- surgeon should make all efforts to reduce transforminal fractures to within 1 cm of being anatomic;
- references:
- The effect of sacral malreduction on the safe placement of iliosacral screws. MC Reilly et al. (15th Annual Meeting of OTA 1999).
-
Small Bowel Obstruction From Entrapment in a Sacral Fracture Stabilized With Iliosacral Screws: Case Report and Review of the Literature.
-
4.5 mm reconstruction plate: (Albert et al 1993);
- indicated for posterior pelvic fractures as well as sacral fractures;
- reconstruction plate is placed along dorsum of the sacral and thru the posterior iliac spines (transiliac plate fixation);
- patient is placed in the prone position;
- two incisions are made over the PSIS which are perpendicular to the iliac wings, and one vertical incision is made over the base of the S1 spinous process;
- dissections are caarried down to the bony surfaces;
- predrill the PSIS to assist w/ reconstruction plate insertion;
- use the 4.5 drill to make 2-3 drill holes 1 cm lateral to the PSIS;
- an appropriately sized 4.5 mm reconstruction plate is chiseled thru the iliac spine, passed along the dorsum of the sacrum to the opposite PSIS;
- the recon plate is appropriately contoured;
- the plate is fixed to the iliac wings using 6.5 mm cancellous screws, w/ two screws inserted into each ilac wing;
- reference:
- Posterior Pelvic Fixation Using a Transiliac 4.5 mm Recon Plate: A clinical and biomechanical study. M.J. Albert et al. JOT 1993. Vol 7. p 226-232.
-
TSRH spinal instrumentation:
- in the report by P Korovessis et al. (Orthopedics. Apr 2000, p 323), 14 consecutive patients with unstable posterior pelvic ring disruption underwent fixation
with Texas Scottish Rite Instrumentation;
- 12 injuries involved sacral fractures (8 frx were type I, 3 were type II, and 1 had a type III);
- authors used parallel verticle incisions centered over the SI joints;
- exposure of the iliac crests are required for screw insertion;
- exposure of the lateral border of the sacrum is required for sacral reduction (requires elevation of erector spinae and
multifidus);
- two pedicle screws are placed in the superior and inferior aspects of each posterior iliac spine;
- pedicle screws are connected using TSRH bars;
- reduction of the SI joint is confirmed by palpation of the surface of the sciatic notch (should have smooth curve);
- the authors note that inaddition to the TSRH fixation, standard fixation with 6.5 mm screws directed into the sacrum may also be performed;
- in this study, there were no occurences of skin necrosis;
Sacral fractures: an important problem. Retrospective analysis of 236 cases.
Transverse fractures of the sacrum. A report of six cases.
Conservative management of transverse fractures of the sacrum with neurological features. A report of four cases.
Orthopaedic management of lumbosacral agenesis. Long-term follow-up.
Sacral agenesis.
Occult sacral fractures in osteopenic patients.
The effect of sacral fracture malreduction on the safe placement of iliosacral screws.
Triangular osteosynthesis of vertically unstable sacrum fractures: a new concept allowing early weight-bearing.
