Cyril Mauffrey and David J. Hak (eds.)Passport for the Orthopedic Boards and FRCS Examination10.1007/978-2-8178-0475-0_3

Spine Anatomy and Surgical Approaches

Jason M. McKean¹ and David Seligson²

(1)

Department of Orthopaedics, Lincoln Medical Center, Bronx, USA

(2)

Department of Orthopaedics, University of Louisville Hospital, Louisville, KY, USA

Jason M. McKean (Corresponding author)

Email: jasonmckean@gmail.com

David Seligson

Email: seligson@louisville.edu

1 Cervical Spine

Posterior approach
- Indications
  
  Fusion
  
  Biopsy
  
  Discectomy
  
  Utilitarian access to posterior cervical spine
- Superficial dissection
  
  Internervous plane
  
  No internervous plane
  
  Midline between paracervical muscles (segmental innervation by cervical rami)
  
  Incise down to posterior aspect of cervical spinous processes
  
  Elevate the paraspinal muscles off the cervical vertebra subperiosteally off the levels and side (for herniated disc) or sides (for fusion) as needed
  
  Elevate as far lateral exposing lamina, facets, and transverse processes as needed
- Deep dissection
  
  Sharply dissect the ligamentum flavum from the leading edge of the inferior lamina
  
  Protect the dura underneath the ligamentum flavum and remove as much as needed to provide access to the dura, nerve roots, or lamina for a laminectomy
  
  Retracting the spinal cord medially will provide access to the cervical disc and vertebral body
- Dangers
  
  Spinal cord and nerve roots
  
  Avoid aggressive spinal cord and nerve root retraction
  
  Venous plexus surrounding cord
  
  Venous plexus in the spinal canal is vulnerable to tearing with retraction
  
  Bipolar cautery is recommending in this proximity to the spinal cord
Anterior approach
- Indications
  
  Discectomy
  
  Fusion
  
  Biopsy
- Superficial dissection
  
  Internervous plane
  
  No internervous plane superficially through the platysma (innervated by branches of the facial nerve)
  
  Deeper dissection is between the sternocleidomastoid muscle (spinal accessory nerve) and the strap muscles of the neck (segmental innervation from C1, C2, and C3)
  
  Deepest muscle dissection is between the left and right longus colli muscles (segmental innervation from C2 to C7)
  
  Incise the fascia over the platysma and split the muscle in line with the fibers
  
  Incise the fascia anterior to the sternocleidomastoid and retract it laterally
  
  Retract the sternohyoid and sternothyroid strap muscles medially and anteriorly
  
  The trachea and esophagus are just deep to these structures
  
  Open the pretracheal sheath and develop a plane between the carotid sheath laterally and the thyroid, trachea, and esophagus medially
  
  Retract the carotid sheath with its vessels laterally with the sternocleidomastoid muscle
  
  If the superior and inferior thyroid arteries coming from the carotid sheath prevent adequate exposure, then ligate these vessels as needed
  
  The prevertebral fascia and the longus colli muscles lie just anterior to the cervical vertebra
- Deep dissection
  
  Dissect through the midline of the longus colli muscle longitudinally over the vertebra
  
  Elevate subperiosteally along with the anterior longitudinal ligament and retract to expose vertebra
  
  Localize the cervical level by placing a needle in the vertebral disc and obtaining a lateral radiograph
- Dangers
  
  Recurrent laryngeal nerve
  
  At the greatest risk during deep dissection
  
  Keeping the retractors under the medial edge of the longus muscles will help protect the nerve
  
  Sympathetic nerves and stellate ganglion
  
  Injury to nerves can cause Horner’s syndrome
  
  Protect the nerves by retracting subperiosteally in the deep dissection
  
  Carotid sheath contents (the carotid artery, carotid vein, and vagus nerve)
  
  Courses deep to and along the anterior border of the sternocleidomastoid
  
  Do not place retractors directly against the carotid sheath