Cervical Spine Approaches
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Cervical Anterior Smith Robinson Approach
- Focus on patient preparation‼️
- Position - Supine, sand bag under shoulder blades, head neutral with slight tilt only to maintain straight line, elevated 30°
- Strap down shoulders to help with II visualization
- Tape the head down at forehead to stabilize
- Dangerous structures - (think by layers)
- Platysma - External jugular vein
- Pretracheal fascia - Superior and inferior thyroid arteries
- Tracheo-esophageal groove - Recurrent Laryngeal Nerve
- Along longus colli - Sympathetic chain
- Dissection - RLN, Sympathetics, thyroid arteries
- Localise clinically and radiologically
- Hard palate C1
- Angle of mandible C2
- Hyoid Cartilage C3
- Thyroid Cartilage C4-5
- Cricoid Cartilage C6
- Incision - horizontal incision at level from posterior border of SCM to midline
- Dissection - Split platysma vertically → identify anterior border of SCM [innervated by Spinal Accessory nerve] → incise DEEP CERVICAL FASCIA → Strap muscles retracted medially → identify Carotid sheath (with vagus nerve inside) → incise PRETRACHEAL FASCIA medial to carotid sheath → Retract carotid laterally, trachea, esophagus medially → ligate inferior thyroid arteries → locate vertebral body (localise again) → incise PREVERTEBRAL FASCIA to expose anterior surface → place retractors under longus colli muscles to protect sympathetic chain on the longus colli
- Left side RLN more predictable but right side easier for right-handers
- Thoracic Duct is on the left side
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- Hypoglossal nerve is prone to injury in high C-spine approach
Lumbar Spine Approaches
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Lumbar Posterior Approach
- Focus on patient preparation‼️
- Appropriate padding from top to bottom (protect 5 nerves)
- Orbital padding to prevent pressure on eyes, supraorbital nerve
- Elbow - flex and pad medial epicondyle to protect ulnar nerve
- Sciatic nerve - knees bent to reduce tension
- Femoral nerve, LFCN - appropriate padding at ASIS
- Abdomen - hang free to prevent venous pooling in the Batson's valveless system
- Position - prone on Jackson table (if lordosis required) or Wilson frame (if interlaminar space needs opening)
- Localization with II
- Incision - midline incision over spinous process
- Dissection - incise through lumbodorsal fascia; paraspinal muscles (multifidus, longissimus, iliocostalis) detached subperiosteally as one unit using Cobb elevators as far as facet joints
- Proceed with laminotomy or laminectomy
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Lumbar Posterior Wiltse Approach
- Incision is 3 cm lateral to midline
- Wiltse approach is muscle splitting between multifidus and longissimus
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Lumbar Anterior Approach - can be Trans or retroperitoneal
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- Primarily for L5/S1
- L4/5 → less suitable due to bifurcation of vessels (may need vascular surgeon)
- Proximal levels less suitable due to risk of SMA thrombosis and retraction
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- Midline for all levels (umbilicus to symphysis)
- L5/S1 - mini-pfannenstiel
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- Advantages - efficient disc space clearance and endplate preparation, allows maximization of implant size and surface area, allows good correction of lordosis
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Lumbar - AnteroLateral Retroperitoneal Approach
- Position - lateral position, can use AMSCO table to break table
- Incision - 12th rib and oblique towards the lateral border of the rectus abdominis muscle about 5cm lateral to midline
- Superficial Dissection - Skin ➔ Subcut ➔ 3 muscles - EO, IO, TF ➔ Plane between retroperitoneal fat and fascia that overlies the psoas muscle ➔ sweep everything anteriorly ➔ ligate lumbar vessels from aorta to mobilize it anteriorly
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Lumbar Fusion Approaches
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- Bone graft spans between transverse processes
- PLF (Posterolateral Fusion) with instrumentation (no Interbody fusion)
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- Laminotomy performed medial to facet. (maybe partial fascectomy); does not seek to stabilize the facet joint
- Access is medial to facet joint
- Down sides - requires alot of nerve root retraction; risk of dural tears
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- To circumvent extent of neural retraction required
- Unilateral laminectomy and facetectomy ➔ allows visualisation without excessive retraction
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- Lateral retroperitoneal transpsoas corridor
- Suitable for T12 = L5
- Not suitable for L5/S1 due to block by iliac crest
- Lateral position
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- Corridor is anterior to the psoas
- Lateral position
- ALIF = Anterior Transperitoneal Approach
Miscellaneous Questions
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- Jackson table → Provides easy imaging access, allows lordosis, and enables flipping patients for 360° procedures
- Wilson frame → Widens the inter-laminar space, allowing treatment of anterior pathology from a posterior approach
- AMSCO table → Facilitates jack-knife positioning for lateral approaches or to further open the interlaminar space in prone position
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- Anatomy
- Superior - Arises from the ventral surface, at 50% of the cranial lamina
- Inferior - Attaches to the leading/superior edge of the inferior lamina
- Medially - No attachment
- Lateral border - medial border of the inferior articulating facet
- Flavectomy
- You can approach either superiorly or inferiorly
- I use a blunt curette to free the inferior edge from the inferior lamina
- Next, use Kerrison rongeur to remove the distal end of the superior lamina, revealing the ligamentum flavum attachment
- Continue using the rongeur to gently remove the ligamentum flavum
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- 4 things lying on the psoas:
- Ureter - lies on the psoas muscle. To identify the ureter, stroke it and observe its peristalsis
- Genitofemoral nerve on the anteromedial surface of psoas (supplies sensation to upper anterior thigh and scrotum)
- Sympathetic chain on Medial border of psoas ➔ disruption will lead to warm red foot on ipsilateral side of approach (sympathetics cause vasoconstriction, so disruption leads to vasodilation) ➔ this creates the appearance that the normal foot is cold and pale
- Retrograde ejaculation (due to injury to superior hypogastric plexus - lying anterior to the lower lumbar vertebrae)
- Middle sacral artery must be ligated or it can become a major source of bleeding [begins at L4/5]
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- PLIF (Posterior Lumbar Interbody Fusion):
- Laminotomy performed medial to facet
- Access is medial to facet joint
- Downsides - requires significant nerve root retraction; increased risk of dural tears
- TLIF (Transforaminal Lumbar Interbody Fusion):
- Developed to reduce neural retraction required in PLIF
- Unilateral laminectomy and facetectomy ➔ allows visualization without excessive retraction
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- Pedicle Screw insertion first
- Interbody Space Preparation:
- Distract by pushing spinous processes
- Perform unilateral facetectomy
- Perform flavectomy
- Prepare endplates while preserving their integrity
- Insert trial and then the cage
- Rod placement and reduction
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