Updated: 10/4/2016

PSF to pelvis for Neuromuscular Scoliosis

Topic
Review Topic
0
0
Questions
1
0
0
Evidence
6
0
0
Techniques
1

Preoperative Patient Care

A

Intermediate Evaluation and Management

1

Obtain focused history and performs focused exam

  • interpret neurological exam

2

Appropriately orders and interprets advanced imaging studies

  • MRI for very atypical curves or if there are other concerns

3

Makes informed decision to proceed with operative treatment

  • describes accepted indications and contraindications for surgical intervention

4

Provides, modifies and adjusts procedure and patient specific post-operative management and rehabilitation

  • postop: 1-2 week postoperative visit
  • wound check
  • diagnose and management of early complications
  • check spinal radiographs in 3 months, 6 months and annually postoperatively to look for evidence of any implant complications
  • postop: ~ 3 month postoperative visit
  • repeat xrays of entire spine (PA/lateral sitting)
  • advance spine restrictions and activity levels
  • diagnosis and management of late complications
B

Advanced Evaluation and Management

1

Provides complex non-operative treatment

2

Recommends appropriate surgical procedures considering indications and contraindications, risks and benefits for complex cases

3

Capable of surgically treating some complications

  • drainage of hematoma
  • debridement of infection
  • has at least 2 units of blood typed and crossed for I and D or hardware removal
C

Preoperative H & P

1

Obtain history and perform basic physical exam

  • need to carefully document neurological status of bilateral lower extremities
  • strength, sensation, reflexes, and primary symptoms

2

Order basic imaging studies

  • PA and lateral radiographic films of the entire spine

3

Screen medical studies to identify and contraindications for surgery

  • confirms no recent infection contraindicating surgery (UTI)
  • consider cardiology evaluation
  • consider pulmonology evaluation
  • consider nutritional evaluation

4

Perform operative consent

  • describe complications of surgery including
  • pseudarthrosis
  • implant misplacement, migration or failure
  • neurologic injury: loss of motor, sensation or bowel/bladder function
  • superficial or deep wound infection
  • dural tear
  • need for reoperation

Operative Techniques

E

Preoperative Plan

1

Identifies components of spinal deformity on preoperative imaging

  • curve type and magnitude
  • pelvic obliquity
  • shoulder balance
  • curve flexibility
  • sagittal alignment

2

Template instrumentation and fusion levels on preoperative imaging studies

  • Determines upper and lower instrumented vertebra
  • Understands indications for including pelvis in fusion

3

Execute surgical walkthrough

  • describe the steps of the procedure to the attending prior to the start of the case
  • describe potential complications and steps to avoid them
F

Room Preparation

P
P

1

Surgical instrumentation

  • pedicle screws, hooks and wires/cables
  • rods
  • allograft bone for fusion

2

Room setup and equipment

  • table
  • radiolucent Jackson spine flat top table
  • neuromonitoring
  • neuromonitoring leads to upper and lower extremities for SSEPs and MEPs
  • C-arm
  • c-arm perpendicular to table
  • Blood products available- typically 2 units PRBCs typed and crossed
  • consider use of TXA
  • consider use of cell saver

3

Patient positioning

  • prone with arms at 90° max shoulder abduction and elbow flexion to prevent axillary nerve injury
  • foam padding on chest at nipple level
  • pads over ASIS and padding (gel, foam or pillows) on knees
  • hips and knees flexed (may flex hips more in cases of severe lordosis)
  • foley in place
Pearls
  • Halofemoral traction may be helpful to passively correct curve and pelvic obliquity
  • When significant weight is being used for traction, blood pressure should be elevated
Pitfalls
  • the more the hips are flexed, the more hyperlordosis of the lumbar spine will be passively corrected
  • however, be careful not to flex hips so much that the pelvis cannot be imaged because the thighs limit position of C-arm
G

Posterior Approach

1

Identify upper instrumented vertebrae (UIV) with c-arm fluoroscopy

2

Make skin incision

  • make a midline incision starting from upper instrumented vertebrae all the way down to the sacrum
  • make the incision through the dermal layer only

3

Dissect subcutaneous tissue down to fascia

  • deepen the incision to the level of the spinous processes

4

Place retractors

  • use weitlaner retractors to retract the skin margins
  • identify the interspinous ligament between the spinous process
  • this has the appearance of a white line
  • as the incision is deepened, keep the retractors (weitlaner, cerebellar) tight to help with the exposure and to minimize the amount of bleeding

5

Preserve interspinous ligament at and above the level of the upper instrumented vertebrae (UIV)

6

Open the cartilaginous caps over the spinous processes at all levels below the UIV

  • incise the cartilaginous caps overlying the spinous processes and expose the spinous process staying in the subperiosteal plane
H

Deep Dissection

1

Perform subperiosteal dissection

  • perform dissection with Cobb and bovie electrocautery laterally out to the level of the transverse process

2

Reposition retractors as needed

  • while exposing, move the weitlaner retractors to a deeper position for retraction and hemostasis
  • it is easier to dissect from caudad to cephalad because of the oblique attachments of the short rotator muscles and ligaments of the spine
  • generally the primary surgeon works from caudad to cephalad while the assistant works from cephalad to caudad so that they can dissect simultaneously

3

Maintain hemostasis

  • coagulate the branch of the segmental vessel just lateral to each facet

4

Expose the sacrum

  • if placing SAI screws expose laterally to identify S1 and S2 foramen

5

If placing iliac screws or Galveston rods: expose the iliac wings

  • using the same skin incision, identify and incise the fascia just lateral to the posterior superior iliac spine (PSIS) on each side
  • subperiosteally dissect the lateral iliac wing down to the sciatic notch
  • use Taylor or Sofield retractors to facilitate the exposure
  • expose the bone of the PSIS by using a rongeur to remove the fibrocartilaginous tissue at the PSIS

6

Confirm that all desired levels are exposed

  • Confirm levels with C-arm
  • the T12 rib can also be used to aid in localizing the levels
I

1. Pelvic fixation with Sacral Alar Iliac (SAI) Screws 2. Pelvic fixation with Iliac Screws or 3. Galveston Rod Preparation

P

1

1. Pelvic fixation with Sacral Alar Iliac screws

  • make a burr hole at starting point
  • starting point between the S1 and S2 foramen, in line with S1 pedicle screw starting point
  • Insert pedicle probe/awl and advance until resistance from sacroiliac joint is in encountered
  • angle towards greater trochanter, approximately 40° laterally and 40° caudally, though this varies with pelvic obliquity/deformity
  • Use c-arm fluoroscopy to confirm that tract is just above the level of the sciatic notch
  • use orthogonal imaging perpendicular to the tract of the probe and parallel to the probe, i.e. teardrop view
  • Advance probe towards anterior inferior iliac spine
  • aim for just above the hip joint, but take care not to enter the hip joint
  • confirm position of probe with c-arm fluoroscopy in both orthogonal imaging perpendicular to the tract of the probe and parallel to the probe, i.e. teardrop view
  • remove pedicle probe/awl and probe tract with ball tip to confirm osseous channel and measure tract
  • length is generally 70-100 mm
  • for adults a minimum diameter of 8.5mm is typical and this may be appropriate for older teenagers, for younger children a smaller diameter may be necessary
  • place screw and confirm position with AP and teardrop fluoroscopic images
Pearls
  • if orientation of pelvis/imaging is unclear, one can dissect along outer table
  • then, place finger in depression of sciatic notch to confirm direction of tract

2

2. Pelvic fixation with Iliac screws

  • make a separate fascial incision over the PSIS. an alternative method is to dissect from midline and enter the medial wall of the iliac crest
  • expose the outer table to visualize trajectory (from PSIS to sciatic notch)
  • use a rongeur just lateral to the PSIS to expose cancellous bone
  • use a lenke probe/awl to create a tract between the inner and outer wall of the iliac wing aiming toward the anterior inferior iliac spine (AIIS) taking care to avoid the sciatic notch
  • probe tract with ball trip probe to confirm osseous channel and measure length of tract
  • place screw in tract and confirm position with c arm fluoroscopy

3

3. Galveston Rod preparation

  • create channel from the PSIS to the lateral ilium by using progressively larger probes
  • this channel should pass just superior to the sciatic notch
  • Insert trial rod
  • once the channel is made, insert a rod (5.5 mm in smaller children) to a depth of 6-7 cm
  • Remove the trial rod
  • Verify bony walls intact and measure depth of channel
  • probe the channel to ensure that the bony walls are intact and measure the depth of the channel for later Galveston Rod Placement
  • Obtain hemostasis
  • use bone wax to plug the hole at the PSIS to prevent blood from oozing before final rod placement
J

Placement of wires, hooks or pedicle screws

P

1

Remove the facets

  • remove the facets with a rongeur, osteotome, burr or bone scalpel
  • start at the L5-S1 articulation and proceed cephalad to the level below the planned upper instrumented vertebrae
  • remove a window of ligamentum flavum at each interspinous region if planning wire passage
  • use gelfoam soaked in thrombin when needed to control local bleeding
  • if needed for additional deformity correction a ponte osteotomy can be performed by removing the facet in its entirety with a combination of a Kerrison rongeur and burr

2

Pedicle screws

  • Identify the pedicle starting point and use a high speed cortical burr to mark starting point and penetrate cortical surface
  • Insert lenke pedicle probe into the pedicle with the tip pointing laterally at the identified starting point and advance to 20mm or alternatively a 2.0 mm drill bit can be used
  • Probe the tract using a flexible sounding probe (ball tip probe) to palpate the superior, inferior, medial and lateral walls and the endpoint (floor)
  • If no breeches are appreciated face Lenke probe medially and advance to anterior cortex or alternatively a 3.2 mm drill bit can be used
  • Probe the tract using a flexible sounding probe (ball tip probe) to palpate the superior, inferior, medial and lateral walls and the endpoint (floor)
  • Measure the depth of the tract
  • Place the pedicle screw slowly in the orientation of the tract that was created
  • Stimulate screws: if less than 6-8mA reevaluate screw position
  • Confirm position of screws with AP and lateral C-arm fluoroscopy
  • For additional details on pedicle screw placement see technique for idiopathic scoliosis

3

Placement of sublaminar wires

  • contour 16 gauge double wires to allow sublaminar passage
  • wire should be bent with a radius of curvature that approximates the width of the lamina
  • roll wires under lamina
  • keep gentle pressure anteriorly to make sure you are not to deep and inadvertently damaging the cord
  • conversely do not push so hard on the undersurface of the lamina that the tip is caught and the wire is levered into the spinal cord
  • pull tip through until ends are of similar lengths, then can cut to separate the double wire
  • separate the wires placing one wire on each side of the spine
Pitfalls
  • it is important to roll rather than push when placing sublaminar wires

4

Placement of Hooks

5

Confirm position of anchors with C-arm fluoroscopy images (not needed for wires or hooks in most cases)

K

Rod contouring

P
P

1

Measure length of rods with rod template

  • add 5-10cm depending upon size and flexibility of the curve
  • cut to appropriate length

2

Contour rods with french or plate benders

Pearls
  • If using SAI screws, the rod will need a sharp bend at lumbosacral junction (around 70 degrees)

3

If placing Galveston Rods:

  • Place hand benders
  • use hand benders to bend the rod at 90 degrees at the marked location
  • place the short end of the rod in the slot at the end of the Galveston Rod benders
  • have an assistant hold the long end of the rod parallel to the operating room table top
  • Place the rod plate benders
  • this should be held vertical to this plane
  • place a rod bender on the short end of the rod to bend the end 90 degrees to a position perpendicular to the operating room table
  • Bend the rods
  • bend the lordosis into the lower rod
  • bend the kyphosis into the upper rod for appropriate sagittal plane alignment
  • bend the second rod so that it mirrors the shape of the first rod
  • Place rod
  • insert the rod on either side of the scoliosis
  • Spread the sublaminar wire apart usually with the distal wire limb passing laterally
  • place a surgical towel over the wires of the second side to prevent confusion
  • Insert the Galveston rod
  • after the wires have been spread insert the initial Galveston rod into the iliac wing and tamp into place at the PSIS
  • Prepare the rods for insertion add the depth of the iliac crest channel and the offset distance from the PSIS to the midpoint of the L5 lamina make a mark at the distance from the end of the straight rod
Pitfalls
  • After placement examine the lateral iliac wing to ensure that the rod didn't penetrate laterally during insertion
L

Rod placement and correction maneuvers

P
P

1

Reduction technique depends on deformity

Pitfalls
  • It is better to use a softer/more flexible rod or do additional contouring for less correction than to pull out anchors
  • After rod is seated additional bending with in situ or L-benders can be performed to optimize correction

2

Attach rods to pelvic anchors and up to the apex of the deformity

  • If using SAI screws can align rods with SAI screws and pedicle screws directly
  • If using iliac screws then will need a connector to attach to rods
  • can consider connecting the concave and convex rods via a connector for added rigidity

3

Use rod holders to push rods over spine

4

Then secure to proximal anchors

  • Can use serial reducers for this step
Pearls
  • especially with weak bone, use serial reducers to load share on multiple fixation points

5

Perform additional compression and distraction as needed

6

Evaluate correction in sagittal and coronal plane

  • The T square of Tolo can be very helpful in intraoperatively assessing that pelvic obliquity is improved and sitting balance has been achieved

7

Torque set screws to maintain correction once optimized

8

If using sublaminar wires:

  • Tighten the wires
  • tighten the sublaminar wires starting at L5
  • sequentially tighten the wires on the side to L1 or L2
  • place downward pressure with rod pusher on the rod as a counterforce to the wire tightening to minimize the chance of wire pull through
  • Contour rods
  • contour the upper end of the rod in the kyphotic position to minimize the risk of pullout of the upper Implants
  • hold manually in place with a rod pusher while the 2 most cephalad sublaminar wires are tightened
  • Tighten remaining wires on convex side
  • Insert the concave side rod into the upper spinal implants
  • Hold the rod into place while the upper two sublaminar wires on the side are tightened
  • tighten the remaining sublaminar wires on the concave side
  • Cut the wire
  • once all the have been tightened cut the twisted wire at a level that leaves them about 1 to 1.5 cm in length
  • consider placement of one additional cross link to stabilize the upper end of the instrumentation at the midthoracic level
  • bend the wire ends and tamp down to prevent dorsal protrusion
Pearls
  • Sublaminar wires or bands can also be used to supplement screws especially with weak bone to avoid screw pullout
  • The wires or bands can be used to do provisional reduction and then rod can be seated in screws

9

Perform decortication

  • decorticate the exposed bony areas through the region of intended fusion with rongeurs and a power burr
N

Wound Closure

P

1

Irrigation and Hemostasis

  • irrigate spine with saline (author's preference is to use a 3L bag of irrigation with castile soap)

2

Place autograft +/- allograft

  • author's preference is to add vancomycin powder- mixing half of it with the bone graft and sprinkling half of it above the fascia once closed
  • place hemovac drain under fascia if there is enough bleeding/multiple osteotomies to raise concern for hematoma formation

3

Close Muscle

  • close muscle layer with 1- vicryl

4

Close Fascia

  • close fascia with 1-vicryl
  • need water tight closure and need to decrease dead space for hematoma

5

Superficial closure

  • subcutaneous with 2-0 vicryl
  • skin closure with buried 3-0 monocryl
  • can also reinforce with surgical glue
Pitfalls
  • many of these children have conditions associated with slow or poor wound healing
  • if risk of dehiscence is high, consider reinforcing with use of additional nonabsorbable suture (3-0 nylon)

6

Dressing

  • soft dressing over incision
  • Author's preference is to use waterproof layer at base to prevent soiling reaching the incision in patients who are developmentally delayed or have impaired sensation/inability to communicate when they have soiled the dressing

Postoperative Patient Care

O

Perioperative Inpatient Management

1

Writes appropriate admission orders

  • IV fluids
  • advance diet when return of flatus
  • pain meds
  • antibiotics
  • continue for 24-48 hours
  • wound care
  • changes dressing when soiled or based on attending preference
  • foley catheter out POD #1 in most cases

2

Inpatient physical therapy

  • start sitting 1-2 days postoperatively
  • increase the periods of siting each day
  • sitting is allowed as much as possible
  • serial neurovascular exams
  • check appropriate labs

3

Appropriately orders and interprets basic imaging studies

  • review postoperative radiographs and identifies mal-positioned pedicle screws, loss of fixation and overall correction

4

Appropriate medical management and medical consultation

5

Discharges patient appropriately

  • pain meds
  • wound care
  • schedule follow up in 1-2 weeks
 

Please rate topic.

Average 5.0 of 1 Ratings

Thank you for rating! Please vote below and help us build the most advanced adaptive learning platform in medicine

The complexity of this topic is appropriate for?
How important is this topic for board examinations?
How important is this topic for clinical practice?
CASE COUNTER (0)
Case ID Date Hospital Faculty CPT Codes
Topic COMMENTS (1)

of images

Private Note