Updated: 10/4/2016

Microdiscectomy

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Cases
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Techniques
1

Preoperative Patient Care

A

Outpatient Evaluation and Management

1

Obtains focused history and perform focused exam

  • describe key physical exam maneuvers (lumbar nerve root function)
  • concomitant and associated orthopaedic injuries
  • differential diagnosis and physical exam tests

2

Interpret basic imaging studies

  • interpret biplanar films of the L-spine

3

Order and interprets advanced imaging studies

  • myelogram
  • CT
  • MRI findings
  • central stenosis
  • foraminal stenosis
  • identifies nerve root anatomy
  • correlate clinical and imaging findings to form clinical diagnosis

4

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

  • single level HNP with radiculopathy

5

Prescribes and manages nonoperative treatment

  • medical management
  • attempts medical management of lumbar radiculopathy (NSAIDs, gabapentin)
  • orders appropriate diagnostic and therapuetic selective nerve root or epidural steroid injections
  • attempts trial of physical therapy
  • referrals to other physicians

6

Makes informed decision to proceed with operative treatment

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

7

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

  • postop: 2-3 week postoperative visit
  • wound check
  • diagnose and management of early complications
  • start formal outpatient physical therapy
  • postop: ~ 3 month postoperative visit
  • resume to full activity
  • advance spine restrictions and activity levels
  • diagnosis and management of late complications
B

Advanced Evaluation and Management

1

Provides complex non-operative treatment

  • individualized care
  • comprehensive informed consent
  • shared decision making

2

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

  • multilevel stenosis with deformity

3

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

  • multi-level stenosis with deformity

4

Capable of surgically treating simple complications

  • drainage of hematoma
  • debridement of infection
C

Preoperative H & P

1

Neurologic Exam

  • carefully documents neurological status of bilateral lower extremities
  • strength, sensation, reflexes, and primary symptoms

2

Recognizes indications for and initiates immediate additional work-up ("Red Flags") or urgent surgical care

  • progressive deficit
  • cauda equina syndrome
  • results from terminal spinal nerve root compression in the lumbosacral region
  • considered one of the few true medical emergencies in orthopaedics
  • key features
  • bilateral leg pain
  • bowel and bladder dysfunction
  • saddle anesthesia
  • lower extremity sensorimotor changes

3

Order basic imaging studies

  • order bipolar radiographs of the L-spine
  • review advanced imaging such as MRI
  • look for specific findings such as spondylolisthesis, central/lateral recess/foraminal stenosis, and levels of involvement

4

Screen medical studies to identify and contraindications for surgery

  • confirms no recent infection contraindicating surgery (UTI)

5

Perform operative consent

  • documents failure of nonoperative measures such as physical therapy and epidural streoid injections
  • describe complications of surgery including
  • cauda equina syndrome
  • recurrence
  • iatragenic nerve root injury
  • infection

Operative Techniques

E

Preoperative Plan

1

Identifies area of decompression on preoperative imaging

2

Execute surgical walkthrough

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

Room Preparation

1

Surgical instrumentation

  • microscope or loupes
  • microdiscectomy set

2

Room setup and equipment

  • table
  • standard radiolucent table with Wilson frame vs. Jackson spine flat top table
  • C-arm
  • c-arm perpendicular to table
  • microscope (optional)
  • microscope in from opposite side of C-arm

3

Patient positioning

  • prone with arms at 90° max abduction and 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
  • bilateral TED hose and SCDs
G

Dissect to Spinous Process

1

Palpate anatomic landmarks

  • identify the coccyx and the sacrum distally
  • identify the spinous processes proximally
  • palpate the iliac crests to identify the L4 vertebral level

2

Localize level of incision with anatomic or radiographic landmarks

  • insert a spinal needle slightly off of the midline
  • direct the spinal needle toward the disk of interest

3

Confirm disk level with fluoroscopy

4

Make midline incision.

  • midline incision with 10blade overlying the spinous processes between paraspinal muscles (erector spinae)
  • ~3-4cm in length for single level

5

Dissect subcutaneous tissue down to fascia

  • insert a cerebellar retractors for fascial exposure

6

Incise the fascia

  • make a vertical incision through the fascia on the side of the disk herniation
  • cauterize lumbodorsal fascia over spinous processes to just lateral of midline
H

Clear Lamina

1

Subperiosteal dissection with Cobb along spinous processes

2

Subperiosteal dissection of lamina

  • cranial to caudal down to lamina

3

Place probe under lamina to identify level radiographically

4

Use Cobb to strip laterally along lamina until facet capsules identified but not violated

5

Place deep retractors for better visualization

I

Laminotomy and Ligamentum Flavum Resection

1

Remove spinous processes of operative levels with rongeur

  • bring in the microscope

2

Create working window

  • use a size 2 angled curet to create a plane between the ligamentum flavum and lamina of the cephalad vertebra
  • use a burr to thin the lamina then complete resection with Kerrison rongeurs
  • the window should extend cephalad from the interspace to the level of the pars interarticularis of the superior vertebra and caudad from the interspace to the superior most 3 mm of the inferior lamina
  • extend the laminotomy laterally to the medial edge of the facet joint complex
  • take a 45 degree Kerrison punch and remove the remaining bone to complete the laminotomy

3

Begin decompression

  • begin with decompression into canal into inferior half of lamina of cephalad vertebrae first with small curette
  • burr lamina and to thin and then complete resection with Kerrison rongeurs

4

Resect ligamentum flavum

  • dissect the ligament flavum from the medial edge of the facet
  • use a 2-0 angled curet to release adhesions between the facet joint capsule and the ligamentum flavum
  • resect the medial 3mm of the facet with a Kerrison punch
  • use Kerrison to resect caudad lamina from inferior vertebra
J

Foraminotomy and Nerve Root Identification

1

Perform foraminotomy

  • use a Kerrison punch and angle it out of the foramen of the traversing nerve root

2

Remove remaining ligamentum flavum with a rongeur

3

Visualize the dura

  • once visualized take a penfield 4 and identify the lateral edge of the traversing nerve root

4

Control epidural bleeding

  • use a combination of bipolar cautery and thrombin soaked gel foam to gain hemostasis

5

Mobilize the traversing nerve root toward the midline

  • this visualizes the disk space
  • place a nerve root retractor around the root and hold the nerve toward the midline
  • use bipolar cautery to coagulate epidural vessels over the disk herniation
K

Microdiscectomy

1

Excise disk

  • use a no. 15 blade to make a slit incision over the disk herniation
  • if the herniation contains lov viscosity material then aspirate the material into the suction tip
  • with high viscosity material use a micropituitary rongeur to remove the material
  • make several passes until all herniated material has been removed
L

Address Interoperative Complications including Dural Tear Repair

1

Perform water tight closure

  • use 4-0 nurulon to close primarily
  • place a fat graft to reinforce the dural closure
N

Wound Closure

1

Irrigation, hemostasis, and drain

  • flush out spine with saline bulb irrigation

2

Close Fascia

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

3

Superficial closure

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

4

Dressing

  • soft incision dressings over spine

Postoperative Patient Care

O

Perioperative Inpatient Management

1

Writes appropriate admission orders

  • IV fluids
  • DVT prophylaxis
  • pain control
  • advance diet when flatus returns
  • foley out when ambulating
  • check appropriate labs
  • wound care
  • changes dressing on POD #2
  • identifies CSF leak

2

Appropriate medical management and medical consultation

3

Prescribe outpatient physical therapy

  • no lifting more than ten pounds
  • no bending
  • no twisting
  • perform isometric, core and hamstring flexibility exercises

4

Discharges patient appropriately

  • pain meds
  • outpatient PT
  • schedule follow up appointment 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

Develop unique complex postoperative management plans when indicated

 

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