Updated: 10/4/2016

Anterior Spinal Fusion

Review Topic

Preoperative Patient Care


Postoperative Management



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

  • postop: 4 week postoperative visit
  • generally off narcotics at this point and resuming school and normal daily activities
  • postop: ~ 3 month postoperative visit
  • repeat xrays of thoracolumbar spine (PA/lat)
  • advance activities and resume sports as tolerated
  • if single rod without anterior support or limited purchase with screws consider bracing for 3 months during activities

Advanced Evaluation and Management


Provides complex non-operative treatment

  • shared decision making
  • comprehensive informed consent


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


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


Capable of surgically treating simple complications


Preoperative H & P


Obtain history and perform basic physical exam

  • evaluate for any symptoms that would be an indication for an MRI (pain that is daily or severe, night pain, radiating pain, weakness, bowel or bladder issues)
  • need to carefully document neurological status of bilateral lower extremities
  • strength, sensation, reflexes


Order basic imaging studies

  • PA and lateral radiographic films of the entire spine
  • bending films to evaluate curve flexibility and if thoracic curve is structural
  • MRI if indicated


Screen patient to identify and contraindications for surgery

  • confirms no recent infection contraindicating surgery (UTI, pneumonia)
  • prior abdominal or thoracic surgery is a relative contraindication for this technique
  • if the minor curves are structural, a more satisfactory result may be achieved with a posterior approach


Perform operative consent

  • describe potential complications of surgery including
  • pneumothorax or hemothorax
  • failure of fusion
  • implant failure
  • neurologic injury (from screw penetration into canal, compromised perfusion when segmentals are ligated, or during deformity correction maneuvers)
  • vascular injury
  • superficial or deep wound infection
  • injury to ureters
  • anticipated temperature asymmetry ( leg will feel warmer on the side of surgery due to dissection of sympathetic chain- often resolves in 6 to 12 months)

Operative Techniques


Preoperative Plan


Identifies level of deformity and plans levels of fusion to correct deformity on preoperative imaging

  • indications are thoracolumbar/lumbar curve which is less than 70 degrees and relatively flexible
  • if thoracic curve is structural (as determined by > 25 degrees on bending films) or has significant associated thoracic rotation on clinical exam this is a contraindication
  • prior thoracic or abdominal surgery is also a relative contraindication


Templates instrumentation on preoperative imaging studies

  • traditionally include Cobb angle- most commonly from T11 to L3
  • shorter fusion may be also be considered
  • if performing short fusion, first determine the apex of the curve
  • If the apex is a disc- then include 2 levels above and 2 levels below (=4 levels in fusion)
  • if the apex is a vertebral body- then include 1-2 level above and 1-2 level below (=3 or 5 levels in fusion)


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

Room Preparation


Surgical instrumentation

  • screws
  • rods (single or dual rod systems)
  • allograft bone for fusion


Room setup and equipment

  • table
  • radiolucent spine flat top table
  • neuromonitoring
  • neuromonitoring leads to upper and lower extremities for MEPs and SSEPs
  • C-arm
  • c-arm perpendicular to table


Patient positioning

  • foley in place
  • place the patient in the lateral decubitus position
  • position the convexity of the curve up
  • place an axillary roll
  • may also place bump under concavity of curve that can be removed at time of curve correction
  • secure the patient with a bean bag


Patient Prep

  • Prep should be wide from spine posteriorly to umbilicus anteriorly

Expose Rib


Mark and make the skin incision

  • in general the rib one level proximal to the most proximally instrumented vertebrae is removed (T10 rib for a T11 to L3 fusion)
  • confirm level with c-arm
  • make an incision directly over the rib: start over the rib insertion (just lateral to spine) and extend distally in line with the rib to the costochondral junction


Dissect through the muscle layers

  • carry the incision through the various muscle layers down to the rib periosteum

Rib Removal


Incise the rib periosteum


Perform subperiosteal dissection of the rib

  • perform a circumferential subperiosteal dissection of the rib
  • place a finger in the subperiosteal layer around the rib
  • then slide either a raytec sponge or retractor or Cobb in the subperiosteal layer along the length of the rib
  • pull distally
  • upward pull ruptures the costochondral junction


Rib Harvest

  • use a rib cutter to harvest the rib as far posteriorly as possible and remove rib


the posterior aspect of the rib periosteum is then incised and the chest cavity is entered

  • the posterior aspect of the rib periosteum is then incised and the chest cavity is entered
  • care is taken to avoid inadvertent damage to the lung parenchyma below
  • tag each side of the rib periosteum with heavy suture to mark for later reapproximation

Exposure of the Vertebra



Identify the retroperitoneal space

  • identify the retroperitoneal space by the retroperitoneal fat pad
  • the retroperitoneal fat pad is a critical landmark


Reflect the peritoneum

  • bluntly dissect the peritoneum off of the abdominal wall and the diaphragm with fingers, a lap sponge or a sponge on a stick


Incise the diaphragm

  • leave a 1 to 2 cm cuff of diaphragm on the thoracic wall
  • place marking stitches to allow reapproximation during closure
  • When placing marking stitches to reapproximate diaphragm use alternating color pairs to make reapproximating easier


Identify the parietal pleura

  • continue to dissect the peritoneum off of the abdominal wall to visualize psoas


Reflect the psoas

  • use bovie electrocautery to partially elevate the psoas off at its insertion on L1 and retract posteriorly to improve visualization of the spine
  • when reflecting psoas, avoid inadvertent injury to the segmental vessels which lie in the midportion of the vertebral body


Identify the segmental vessels

  • once the diaphragm is dissected down to the parietal pleura, incise the parietal pleura and identify the segmental vessels
  • place a chest spreader (finochietto retractor) and or Balfour retractor to allow visualization of the chest and the abdomen


Ligate the segmental vessels

  • elevate the segmental vessels by using a right angle hemostat, which can then be used to pass a silk suture around the vessel, alternatively ligate vessels with a harmonic scalpel
  • during this portion of the procedure MAPs should be elevated to 75 mm Hg (avoid hypotension)
  • tie the sutures to ligate the vessel


Cut the segmental vessels

  • cut between the silk ties and retract the segmental vessels anteriorly and posteriorly with blunt dissection
  • sharply free any soft tissue attachment to the vessels


Alternative technique: vessel clips are used instead of silk ties to clamp off vessels. Neuromonitoring signals are then checked after approximately 10 minutes. If there are changes then the clips are removed.


Disc Removal and Endplate Preparation



Identify the discs

  • complete exposure of the disc to its posterior edge and anteriorly around to the contralateral side of the spine
  • palpate the annulus on the contralateral side to confirm adequate exposure


Incise the annulus with a scalpel (long handle usually needed)

  • this makes the annulus easier to remove with a rongeur
  • cut with scalpel from anterior to posterior to avoid inadvertent injury to vessels if scalpel slips
  • incise the disc with a large rectangular cut; going along the edge of the endplate


Remove the disc

  • complete disc removal is critical for fusion
  • remove the incised annulus fibrosis and nucleus pulposis with a Lexel rongeur and/or disc shaver
  • avoid removing PLL and/or in most cases, this helps protect against neurologic injury and reduces bleeding
  • begin disk excision at the apex of the deformity
  • this allows some collapse of the spine and greater access to the proximal and distal disks


Remove bone down to the endplates or remove the endplates (some surgeons leave endplates in place for strength)

  • if removing endplate: separate the endplate from the vertebral body using a Cobb elevator
  • turn the elevator so that it slides down the endplate
  • remove each endplate with a rongeur after it is completely freed with a Cobb
  • remove additional endplate and disc using ring curettes, regular curettes, pituitary rongeurs or Kerrison rongeurs
  • place gelfoam or surgicell in the disc space to minimize endplate bleeding

Screw Placement



Choose the implants

  • there are both single rod and double rod systems
  • if using a single rod- screw system the rod diameter should be ΒΌ inch (6.35) in diameter with large diameter screws (6.5 mm-7.5mm)
  • when placing the screws, fully visualize the endplates of the vertebra to allow for parallel placement of screws to the endplates


Identify position on the vertebra

  • identify the anterior and posterior margins of the vertebral body
  • when a single screw is used it is placed in the midposterior aspect of the vertebral body


Create tracts for screws

  • if using a staple, place the staple at the posterior edge of the vertebrae
  • the screws enter towards the posterior portion of the vertebral body to avoid creating kyphosis during compression
  • create a tract for the screw or screws through the staple with an awl or lenke probe; advance across the vertebral body to the contralateral cortex
  • when developing tract consider the amount of rotation; apex screws may need to have a trajectory that is aimed more anteriorly


Place the large diameter screws

  • use a ball tip probe to measure the length of the tract through the vertebral body
  • when using the 2 screw system, place the posterior screw first then the anterior screw
  • place the screws in a convergent manner to increase pullout strength
  • it is very important to place the most proximal and distal screws parallel to the endplate
  • Screw tips may be bi-cortical for additional purchase, with 4mm or less of prominence
  • it is best to err on directing the screws slightly towards the apex of the deformity to account for screw plow

Rod Placement and Spine Correction



Place autograft

  • divide the harvested rib into small segments
  • place the pieces into the disc space
  • place these pieces as posterior and as lateral on the concave side as possible


Correct the spinal deformity

  • use rod rotation to perform the primary corrective maneuver
  • this works very well with correcting coronal plane deformities as well as maintaining sagittal plane lordosis


Check that the degree of correction is sufficient

  • if minimal adjustments need to be made, perform the correction with in situ bending of the rods
  • take an AP to ensure that overall correction is achieved
  • take a true lateral to ensure that the screws are not placed in the vertebral canal
  • wait to perform compression for correction until after anterior structure support is placed
  • this will help to avoid losing lordosis or creating kyphosis


If using cages, position them for anterior structural support

  • this is usually done after rod rotation primarily because of the concern of the stiffening the intervertebral segments
  • place the anterior structural support in the levels distal to T12 to maintain lordosis, to correct the curve and increase the overall sagittal plane stiffness of the construct
  • at each segment perform distraction to seat the anterior structural support


Perform compression

  • perform compression to secure the anterior structural support or bone graft
  • perform the compression in sequential levels from proximal to distal


Place additional bone graft (autograft or allograft) to completely fill the disc space


Close the parietal pleura

  • perform closure by initially closing the parietal pleura over the implant with running vicryl suture

Wound Closure


Close the diaphragm

  • close the diaphragm with interrupted sutures with pop off needles


Place a chest tube if chest was entered, usually not needed in lumbar only fusions

  • usually a 24 french
  • tunnel over one of the more cephalad ribs


Close the chest

  • reapproximate the chest with the rib approximator and multiple large 1-0 vicryl sutures
  • oversew the periosteum with a 2-0 stitch
  • close the muscle layers sequentially


Close Fascia

  • close fascia with 0-vicryl


Superficial closure

  • subcutaneous with 2-0 vicryl
  • skin closure with buried 3-0 monocryl



  • soft dressings over incision

Postoperative Patient Care


Perioperative Inpatient Management


Writes appropriate admission orders

  • Chest radiograph is obtained at the conclusion of the procedure on the PACU area to evaluate for any pneumothorax
  • IV fluids
  • clear liquids until bowel sounds present
  • once bowel sounds present start on soft diet and ADAT
  • POD 1 begin mobilizing with physical therapy
  • aggressive pulmonary toilet to prevent atelectasis and pneumonia
  • take an xray 1 hour after removal of the chest tube
  • pain meds
  • antibiotics
  • continue for 24-48 hours (surgeon preference)
  • wound care
  • changes dressing on POD #2 or prior to discharge (surgeon preference)
  • foley catheter out when ambulating
  • serial neurovascular exams
  • CBC in AM


Appropriately orders and interprets basic imaging studies

  • review postoperative radiographs and evaluates implant position


Discharges patient appropriately

  • pain meds
  • wound care instructions
  • schedule follow up in 2 weeks

Complex Patient Care


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


Develops unique complex postoperative management plans when indicated


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