Updated: 10/4/2016

Growing Rod Instrumentation

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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 of cervical thoracic and lumbar spine preoperatively

3

Prescribes and manages nonoperative treatment

  • medical management
  • make referrals to other professionals

4

Makes informed decision to proceed with operative treatment

  • documents failure of nonoperative management
  • describes accepted indications and contraindications for surgical intervention

5

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

  • postop: 4 week postoperative visit
  • wound check
  • diagnose and management of early complications
  • postop: ~ 3 month postoperative visit
  • repeat xrays of lumbar spine
  • look for evidence of fusion
  • advance activity restrictions
  • diagnosis and management of late complications
B

Advanced Evaluation and Management

1

Provides complex non-operative treatment

  • individualized care
  • shared decision making
  • comprehensive informed consent

2

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

3

Completes comprehensive pre-operative planning with alternatives and criteria for acceptable intraoperative result for complex cases

4

Capable of surgically treating simple complications

  • drainage of hematoma
  • debridement of infection
C

Preoperative H & P

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
  • often challenging in small or developmentally delayed children: having patients heel walk, toe walk and jump up and down on one foot independently will help assess overall function

2

Order appropriate imaging studies

  • PA and lateral radiographic films of the entire spine
  • traction or bending films of spine
  • MRI of cervical, thoracic and lumbar spine to rule out intraspinal pathology
Pearls
  • For children with congenital scoliosis an echo and renal ultrasound should also be performed

3

Screen medical history to identify any contraindications for surgery

  • confirms no recent infection contraindicating surgery (pneumonia, UTI)
  • echo if curve is greater than 75 degrees to check for pulmonary hypertension
  • pulmonology eval if patient has any underlying restrictive or obstructive lung disease or if the curve is greater than 80 degrees

4

Perform operative consent

  • expected need for reoperation for lengthening, revisions and conversion to final fusion at approximately age 10
  • implant misplacement, migration or failure
  • neurologic injury with loss of motor and sensation as well as bowel and bladder function
  • superficial or deep wound infection requiring further surgery and prolonged antibiotic use
  • dural tear
  • pneumothorax
  • crankshaft
  • implant prominence
  • progression of the deformity above or below the instrumented segment
  • continued progression of the curvature despite instrumentation
  • neither in person nor on X-ray will the spine ever appear completely normal

Operative Techniques

E

Preoperative Plan

1

Template instrumentation on preoperative imaging studies.

2

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

1

Surgical instrumentation

  • Pedicle screws and hooks
  • Rods (4.75 and 5.5 available)
  • Allograft bone for fusion

2

Room setup and equipment

  • table
  • radiolucent Jackson spine table
  • small chest pad and 2 iliac crest pads
  • neuromonitoring
  • neuromonitoring leads to upper and lower extremities
  • C-arm
  • c-arm perpendicular to table

3

Patient positioning

  • foley and neuromonitoring leads placed prior to prone positioning
  • bite block placed to prevent tongue injury from neuromonitoring stimulation
  • prone with arms at 90° max abduction and elbow flexion to prevent axillary nerve injury
  • foam padding on chest so that nipples are pointing midline straight down
  • pads over ASIS and gel pads on knees
  • hips and knees slightly bent
Pearls
  • If placing hooks on upper ribs (T1/T2), brachial plexus irritation may occur when arms are adducted (not there when abducted)
  • In these cases consider positioning with arms at the side so this is detected intraoperatively rather than postoperatively
G

Posterior Approach

1

Mark incisions for upper and lower foundations

  • Foundations consist of vertebral segments at either ends of the construct which are internally fixed with anchors with at least 2 pairs of anchors spanning 2 or 3 vertebral levels
  • identify the levels for anchor placement with C-arm flouroscopy
  • approximately 5-8 cm incision for superior anchors and 5-8 cm incision for inferior anchors

2

Make midline incision

  • midline incision with 15 blade overlying the spinous processes

3

Deepen the dissection with bovie electrocautery to the level of the spinous processes

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

4

Expose the spinous processes of the cranial and caudal foundations

  • carefully preserve the interspinous ligament above and below the levels of the anchors
  • use a metallic object (needle or hemostat) to confirm levels with C-arm fluoroscopy prior to deepening exposure
H

Deep Dissection

P
P

1

Expose the posterior elements

  • expose the posterior elements of the cranial and caudal foundations subperiostealy out to the level of the transverse process
Pearls
  • If rib fixation is being used for proximal anchors, then two separate fascial incisions can be made just lateral to TP
  • In these cases, subperiosteal exposure of spine for upper anchors can be avoided completely
Pitfalls
  • Vertebral levels that are not involved in the anchor foundation should not be exposed to prevent unwanted fusion
I

Place the lower anchors (lumbar pedicle screws in most cases)

1

Facet joints exposed only within intended fusion

2

Facetectomies are performed at levels within the intended fusion with either a rongeur, osteotome, burr or bone scalpel

3

Identifies starting point for pedicle screws

  • in the lumbar spine the pedicle is located at the junction of the pars interarticularis and the midpoint of the transverse process
  • if anatomy is unclear, can check starting point with c-arm fluoroscopy
  • a burr is used to penetrate the cortex at this location

4

develop the tract with a Lenke probe (or small drill)

  • screw trajectory from lateral to medial is generally 10 degrees at L1 and gradually increases to 30 degrees at L5
  • the lenke probe is inserted to 20mm facing laterally, or use 2.0 drill bit
  • the tract is then checked with a ball tip probe to check for any cortical breeches
  • if there are no breeches then the lenke probe is reinserted facing medially, or a 3.2 mm drill bit is advanced to the anterior cortex

5

Screw placement

  • the tract is then checked with a ball tip probe to evaluate for any breeches
  • if there are no breeches then the probe is used to measure the length for the appropriate size of screw (this is done by inserting the probe until it is on the anterior cortex, clipping a hemostat at the insertion site and then holding it up against the screw to be inserted to see that the length is as long as the screw shaft)
  • the screw is then inserted in the same trajectory
  • position and length of screws are checked with c-arm fluoroscopy
  • screws are stimulated and if below 6-8 mAs, screw trajectories re-assesed from within the canal and/or within the screw tract after removing the screw.
  • generally 4 lumbar pedicle screws are placed as the distal anchor vs. pelvic fixation
J

Place the upper anchors

P

1

thoracic pedicle screws

  • Facetectomies are performed at levels of intended fusion with either a rongeur, osteotome, burr or bone scalpel
  • the starting point for screw placement is just lateral to the midpoint of the facet joint
  • from cranial to caudad the starting point is:
  • upper thoracic spine= level of midpoint of transverse process
  • middle thoracic spine (T7-T9)= level of superior aspect of transverse process
  • the trajectory of the screw is usually 15-25 degrees lateral to medial in the upper thoracic spine (T1-T3) and decreases to 10 degrees for T4 to T9
  • screws are placed as described above for lumbar pedicle screws

2

rib hooks

  • if using rib hooks split paraspinous muscle just lateral to TP down to rib periosteum
  • it is optional to make a 5-mm transverse incision with bovie electrocautery just distal to the neurovascular bundle and immediately adjacent but lateral to the transverse process
  • use freer elevator to dissect soft tissue anterior to the rib (develop plane between the periosteum and the pleura)
  • alternatively, insert hook bluntly with moderate force, first pushing anteriorly, and rotating to end pushing the hook in a cephalad direction
  • the neurovascular bundle caudad to each rib is of no consequence
Pearls
  • try to preserve rib periosteum to allow area to hypertrophy in response to stress

3

Confirm position of lower and upper anchors prior to rod placement

  • use c-arm fluoroscopy to evaluate position of implants
  • stimulate pedicle screws that are at the level of T6 or below
K

Rod and Connector Placement

P

1

cut and contour rods

  • measure the length from upper to lower anchors
  • cut the rods longer than measured as there will be some distraction that occurs at the time of placement (generally add about 5-10 cm- more if large and flexible curve)
  • contour rod with french benders- kyphosis through the thoracic spine and lordosis through the lumbar spine

2

Plan position of connectors and cut rod accordingly

  • tandem connector should be positioned in region of thoracolumbar junction where spinal alignment is relatively neutral
  • if patient has a large amount of kyphosis then the side to side connectors can be used rather than a tandem connector (for kyphosis correction a single incision from upper to lower anchors may be needed to allow for levering rods into place
  • cut the rod within the connector and secure each end of the rod in the connector with set screw

3

Tunnel rod in the submuscular plane

  • use finger to bluntly dissect just above ribs from superior incision and from level of transverse process from inferior incision
  • use a tonsil or other long clamp to connect these channels
  • place tonsil from superior to inferior and open clamp to secure chest tube
  • pull chest tube through sub muscular tunnel
  • place end of rod/connector construct into the end of the chest tube (approx 20 french) and slide through the tunnel
  • avoid pushing rod anteriorly and inadvertently entering into the thorax (palpate rod after placement to confirm posterior not anterior to ribs)
Pitfalls
  • Be sure you can palpate clamp all the way along (avoid tunneling below the ribs)
L

Reduction

P

1

Place set screws to secure rods in upper anchors first

2

Place set screws in lower anchors and secure

3

Perform correction

  • place a rod holder just proximal to inferior anchors
  • check that blood pressure is elevated (MAP greater than 75)
  • confirm with neuromonitoring that the SSEPs and MEPs are present and stable
  • place a distractor between the rod holder and the lower anchors
  • loosen the inferior set screws, distract and retighten set screws
Pearls
  • Ideally, distraction at initial implant placement is performed on rods left long outside of anchors
  • This leaves the rod within the "growing connector" as long as possible to allow for future lengthenings

4

recheck neuromonitoring after the correction

N

Wound Closure

1

Use C-arm fluoroscopy to evaluate correction and balance in the coronal and sagittal planes

2

If rib hooks were placed, fill wound with saline and ask anesthesiologist to perform a valsalva maneuver to check for any evidence of pneumothorax

  • decorticate surrounding transverse processes, facet joints, and pars with burr at the levels of intended fusion

3

Irrigate copiously: can use betadine solution or castile soap in addition to saline

4

Place bonegraft

  • add bonegraft at level of intended fusion
  • can use vancomycin powder in graft and/or around implants

5

Place hemovac drain if indicated (not needed in many cases)

6

Deep closure

  • Close muscle with 0-vicryl
  • Close fascia with 0-vicryl
  • need water tight closure and need to decrease dead space for hematoma

7

Superficial closure

  • subcutaneous with 2-0 vicryl
  • skin closure with buried 3-0 monocryl
  • reinforce with nylon horizontal mattress suture if needed
  • surgical glue or adhesive sometimes also applied depending on surgeon preference

8

Dressing

  • if developmentally delayed (incontinent), reinforce inferior aspect of dressing with iodine impregnated dressing or other water resistant dressing

Postoperative Patient Care

O

Periopoerative Inpatient Management

1

Writes appropriate admission orders

  • IV fluids
  • advance diet when bowel sounds present or return of flatus (attending preference)
  • pain meds
  • antibiotics
  • continue for 24 hours
  • wound care
  • changes dressing if drainage, sweaty or soiled or on POD #2 (attending preference)
  • foley catheter out on POD 1
  • serial neurovascular exams
  • check appropriate labs: CBC on POD 1
  • TLSO brace for 3 months when out of bed in most cases

2

Appropriately orders and interprets basic imaging studies

  • upright PA chest radiograph in PACU to check for pneumothorax
  • standing (or sitting if nonambulatory) PA and lateral thoracolumbar spine X-ray prior to discharge
  • review postoperative radiographs and identifies mal-positioned pedicle screws

3

Appropriate medical management and medical consultation

4

Inpatient physical therapy

  • weight-bearing as tolerated
  • TLSO brace for 3 months when out of bed in most cases

5

Discharges patient appropriately

  • pain meds
  • wound care
  • outpatient PT if indicated
  • schedule follow up in 2 weeks
R

Complex Patient Care

1

Completes comprehensive pre-operative planning with alternatives and criteria for acceptable intraoperative result for highly complex cases

  • revision surgery

2

Develops unique complex postoperative management plans when indicated

 

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