Thoracic Disc Herniation — Discectomy

Surgical Indications

Absolute Indications

• Progressive myelopathy due to thoracic disc herniation — the presence of cord signal change, gait disturbance, lower limb hyperreflexia, clonus, or bladder/bowel dysfunction constitutes a surgical urgency
• Acute paraplegia from a compressive thoracic disc herniation — requires urgent decompression
• Intractable radiculopathy with radicular pain or intercostal neuralgia that has failed a trial of non-operative care (analgesics, activity modification, intercostal nerve blocks) for 6-12 weeks
• Cord compression with significant spinal canal compromise (greater than 40% canal encroachment or cord deformation on MRI) even without dense myelopathy — due to risk of progression

Relative Indications

• Persistent radiculopathy without cord signs that significantly impairs quality of life
• Herniation discovered incidentally in a patient undergoing surgery at an adjacent level — if accessible through the same approach
• Progressive deformity or segmental instability developing from the disc height loss and endplate changes

Contraindications

Absolute:

• Asymptomatic thoracic disc herniation found incidentally on MRI — the vast majority of thoracic disc herniations are asymptomatic and require no treatment
• Active systemic infection or uncontrolled coagulopathy
• Medical comorbidities precluding the planned approach (poor pulmonary reserve for transthoracic approach; severe osteoporosis for any instrumented reconstruction)

Relative:

• Multilevel degenerative disease where the symptomatic level cannot be confidently identified
• Previous ipsilateral thoracotomy or chest pathology (pleural adhesions) making transthoracic approach hazardous — consider contralateral approach or alternative approach
• Morbid obesity (BMI greater than 40) — increases technical difficulty of all approaches and wound complication risk

Evidence for Non-Operative Treatment

Observation and Conservative Care

• The natural history of asymptomatic thoracic disc herniations is generally benign — most do not progress or become symptomatic (Wood, 1995)
• For patients with radiculopathy alone, a trial of observation, simple analgesics (paracetamol, NSAIDs), activity modification and physiotherapy is reasonable for 6-12 weeks
• Neuropathic pain agents (gabapentinoids, amitriptyline) may help radicular symptoms but have no effect on cord compression — their use must not delay surgical referral if myelopathy develops
• There are no RCTs directly comparing operative and non-operative management for symptomatic thoracic disc herniation — all evidence is from case series

Intercostal Nerve Blocks and Epidural Steroid Injections

• Image-guided (CT or fluoroscopic) intercostal nerve blocks can provide temporary relief of radicular symptoms and help confirm the symptomatic level
• Transforminal epidural steroid injections at the thoracic level carry a higher risk of spinal cord injury than in the lumbar spine and are not routinely recommended
• Chelation (chemonucleolysis) has no role in the thoracic spine

Evidence for Surgery

Outcomes by Approach

• Transthoracic approach: Stillerman (1998) reported a good/excellent outcome in 82% of 82 patients undergoing anterior decompression for thoracic disc herniation, with the best outcomes in patients with myelopathy or radiculopathy without preoperative deficit longer than 6 months
• Posterolateral approaches: Borm (2004) reported satisfactory outcomes in 80% of patients undergoing transpedicular discectomy, with lower morbidity than transthoracic approaches but limited application to lateral/foraminal herniations
• Lateral extracavitary approach: An extensile option that provides ventral access without entering the pleural cavity — useful for herniations at the thoracolumbar junction and for revision cases

Prognostic Factors

• Duration of symptoms: Patients with preoperative myelopathy for less than 6 months have significantly better neurological recovery than those with longer-standing deficits (Levi, 1999)
• Disc calcification: Calcified discs have higher complication rates (dural tear, incomplete resection) but equivalent clinical outcomes when completely resected via an appropriate anterior approach
• Age: Younger patients (less than 50 years) have better functional recovery, but surgical decompression is effective across all age groups

Key Evidence

Thoracic Spine Osteology

Vertebral Anatomy

• Vertebral body: Heart-shaped on axial view (wider laterally than AP), with costal facets on the posterolateral body for the rib head articulation. The size increases from T1 to T12 as load-bearing demands increase
• Pedicles: Short, stout and directed posterolaterally. The thoracic pedicle is narrower (mean 4.5-5.5 mm diameter) than any other spinal region — pedicle screw placement is technically demanding and requires precise trajectory
• Laminae: Broad and overlapping (shingled) in the upper and mid-thoracic spine, providing intrinsic stability but limiting interlaminar access
• Spinous processes: Long, slender and steeply downward-angled (especially T3-T10) — the tip of one spinous process lies at the level of the vertebral body below
• Transverse processes: Thick and project posterolaterally — articulate with the rib tubercle (costotransverse articulation). The transverse process provides the attachment for the costotransversectomy exposure

Rib Cage and Costovertebral Articulations

• Each rib articulates with the vertebral body at two points: the costovertebral joint (rib head with the vertebral body and disc) and the costotransverse joint (rib tubercle with the transverse process)
• The rib head covers the posterolateral corner of the disc space — in costotransversectomy approximately 3-4 cm of the rib is resected to expose the disc
• In the upper thoracic spine (T1-T4), the ribs are short and the scapulae overlie the posterior chest wall, making access more difficult

Key Surface Landmarks for Level Counting

• C7 (vertebra prominens): The most prominent spinous process at the base of the neck — but note that C7 and T1 are difficult to distinguish clinically. The first rib articulates with T1 — the most reliable starting point for counting on any imaging modality
• T4: At the level of the sternal angle (Angle of Louis)
• T7: At the inferior angle of the scapula (with arms at the side)
• T12: At the 12th rib — but remember that a rudimentary 12th rib may be absent or very short, making counting from below unreliable
• Intraoperative rule: Surface landmarks are unreliable. ALWAYS obtain intraoperative radiographic confirmation with a marker at the index level

Spinal Cord and Vascular Anatomy

Spinal Cord

• The thoracic spinal cord occupies a greater proportion of the spinal canal (approximately 40-50% of canal area) than the lumbar cord (less than 25%) — less reserve space
• The cord tapers to the conus medullaris at approximately L1 in adults
• Watershed zone: The mid-thoracic region (T4-T9) is the vascular watershed of the spinal cord — the anterior spinal artery is at its narrowest here, supplied by the fewest radicular feeders. This region is most vulnerable to ischaemia from hypotension, retraction or segmental vessel sacrifice

Anterior Spinal Artery

• Formed from the vertebral artery branches at the craniocervical junction, reinforced by a variable number of anterior radicular arteries (usually 6-10) at segmental levels
• Supplies the anterior two-thirds of the cord (corticospinal tracts, spinothalamic tracts)
• Injury produces anterior cord syndrome: bilateral motor loss (corticospinal), loss of pain and temperature (spinothalamic), but preserved posterior column function (vibration, proprioception, light touch)

Artery of Adamkiewicz (Great Anterior Radicular Artery) — The Critical Vessel

Posterior Spinal Arteries

• Paired vessels running along the posterolateral cord, supplied by posterior radicular arteries
• Supply the posterior one-third of the cord (dorsal columns — proprioception, vibration, light touch)
• Less clinically vulnerable than the anterior spinal artery due to better collateralisation

Approach-Specific Anatomy

Posterolateral (Transpedicular) Approach

• Working corridor: Through the pedicle, lateral to the spinal cord, reaching the posterolateral disc space
• Resection: Partial or complete facetectomy (the level of the herniated disc and the facet above) — may destabilise the motion segment if both facets are resected
• Angle of view: The surgeon looks from posterolateral to anteromedial, reaching the lateral disc space — the spinal cord is behind the disc, and instruments work tangential to the cord
• Limitation: Cannot reach across the midline for central disc herniations — attempting to do so pushes instruments toward the cord

Costotransversectomy Approach

• Bone resection: Resection of the transverse process and the medial 3-4 cm of the rib (including the rib head) at the level of the herniation
• Working corridor: Through the costotransverse defect, lateral and slightly anterior to the spinal cord — provides a more lateral angle of approach than the transpedicular route
• Key structures encountered: Costotransverse joint ligament, intercostal neurovascular bundle (neurovascular bundle runs in the subcostal groove — protect it)
• Cord safety: Better angle than transpedicular for central-lateral discs but still cannot safely address midline central discs

Lateral Extracavitary Approach

• Working corridor: A posterolateral exposure that combines features of costotransversectomy and a lateral retropleural approach — a larger flap of skin and muscle is mobilised to reach the lateral vertebral body and disc
• Resection: Resection of the transverse process, rib head and lateral vertebral body to create a working channel anterior to the cord
• Advantage: Ventral access without entering the pleural cavity — useful for thoracolumbar junction discs and revision surgery where adhesions contraindicate a transpleural approach
• At-risk structures: Segmental vessels (including possible Adamkiewicz), intercostal nerve (intentional sacrifice may be needed), pleura (retropleural dissection preserves it)

Transthoracic (Transpleural) Approach

• Working corridor: Through the chest — the lung is deflated (double-lumen endotracheal tube), a rib is resected or the intercostal space is spread, and the pleural cavity is entered
• Target: The lateral vertebral body and disc space — the disc is approached from ANTERIOR to the cord, allowing direct visualisation of the ventral dura
• At-risk structures: Intercostal neurovascular bundle, segmental vessels (ligate away from the aorta), azygos/hemiazygos veins (right side), thoracic duct (left side at T4-T6), lung, diaphragm (if approaching T11-T12)
• The key anatomical advantage: The disc and ventral cord are seen under direct vision — the disc is resected from anterior to posterior, toward the surgeon, away from the cord

Preoperative Planning and Level Localisation

Imaging Review

• MRI (sagittal + axial T1/T2): Classify the herniation as lateral, posterolateral, central or broad-based. Assess cord compression, cord signal change (myelomalacia), and any associated endplate changes
• CT (sagittal + axial): Essential before every thoracic discectomy — assess for disc calcification, osteophytes and intradural extension. A calcified disc changes the surgical approach
• CTA or MRA of the thoracic spine: Strongly recommended before an anterior or lateral approach at T5-L2 — map the artery of Adamkiewicz. If it arises at or immediately adjacent to the herniation level, approach modification is required

Approach Selection Algorithm

• Lateral/foraminal herniation (disc extends into the neural foramen lateral to the cord) — Transpedicular or costotransversectomy approach
• Central-lateral herniation (crossing midline but reaching one side) — Costotransversectomy or lateral extracavitary approach
• Central/broad-based herniation (crossing midline symmetrically, no lateral extension) — Transthoracic (anterior) approach
• Calcified central disc (hyperdense on CT) — Transthoracic or lateral extracavitary approach — mandatory, not optional
• Upper thoracic (T1-T4) — Consider posterolateral approach (the sternum, great vessels and mediastinum limit anterior access at these levels)
• Thoracolumbar junction (T11-T12) — Lateral extracavitary approach avoids the diaphragm and pleural complications, or consider transthoracic with diaphragmatic detachment

Level Localisation Protocol

• Preoperative: Obtain a full-length AP and lateral radiograph of the thoracic spine to count and mark the levels. Count from T1 (first rib) on the sagittal MRI localiser — correlate with the radiograph
• Intraoperative: Place a spinal needle, k-wire or haemostat in the spinous process of the level BELOW the index disc, or mark the transverse process at the index level. Obtain an intraoperative lateral radiograph or O-arm CT to confirm
• Pearl: It is safer to mark two adjacent levels (the target and one level above/below) and confirm both — the surgeon can then count to the disc space using the confirmed levels as reference

Positioning and Setup

General Principles

• Anaesthesia: General anaesthesia with neuromuscular blockade (short-acting for MEP monitoring). For transthoracic approach: double-lumen endotracheal tube for selective lung ventilation; place an arterial line and consider a central line for major blood loss
• Intraoperative neuromonitoring: MEP and SSEP are mandatory for all thoracic discectomy cases. Obtain baseline recordings after positioning but before incision. Alert thresholds: MEP amplitude drop greater than 50% from baseline, SSEP amplitude drop greater than 50% or latency increase greater than 10%
• Blood pressure: Maintain mean arterial pressure greater than 80 mmHg throughout the spinal cord decompression phase — spinal cord perfusion must be optimised
• Cell saver: Consider for transthoracic and lateral extracavitary approaches where blood loss may be greater than 500 mL

Position by Approach

Posterolateral (transpedicular/costotransversectomy) — prone position:

• Standard prone frame (Jackson, Wilson or four-poster) with chest and iliac crest supports, abdomen free to reduce epidural venous pressure
• Arms positioned above the head (ski-jump position) — allows lateral fluoroscopy
• Slight reverse Trendelenburg to reduce venous pressure
• The thoracic kyphosis is maintained (do not flatten — this narrows the spinal canal and increases cord tension)

Lateral extracavitary — prone or three-quarter prone (45 degrees):

• The side of the herniation is elevated to provide a more lateral working angle
• The operating table is flexed slightly to open the intercostal spaces on the approach side

Transthoracic (transpleural) — lateral decubitus:

• The side of approach is determined by herniation location (usually the side of greater disc displacement if asymmetrical, or the right side for central discs to avoid the heart, aorta and thoracic duct)
• Place an axillary roll below the dependent axilla, flex the table to open the intercostal spaces
• The arm is placed in an overhead armrest or supported on a Mayo stand — avoid brachial plexus stretch
• Confirm deflation of the ipsilateral lung after positioning (bronchoscopy to confirm double-lumen tube position before draping)

Posterolateral (Transpedicular) Approach — Step-by-Step

Indication

Lateral/foraminal thoracic disc herniation — disc that lies lateral to the cord and can be reached through the pedicle and facet without medial retraction of the cord.

Step 1: Incision and Exposure

• Midline longitudinal incision centred over the index level, extending two levels above and one level below
• Subperiosteal dissection of the paraspinal muscles to expose the spinous processes, laminae and transverse processes of the target and adjacent levels
• Confirm the level with intraoperative radiography or navigation — place a marker on the transverse process or lamina of the target vertebra, obtain an AP and lateral X-ray. Cross-reference the count from the preoperative localiser

Step 2: Facetectomy and Pediculotomy

• Using a high-speed burr (3-4 mm diamond or cutting burr), resect the inferior facet of the vertebra above and the superior facet of the vertebra below at the index level (partial facetectomy)
• Identify the pedicle — it lies at the junction of the transverse process and the lateral lamina
• Drill into the pedicle using a curved curette or burr, removing the cancellous bone of the pedicle to create a 8-10 mm window into the posterolateral disc space. The pedicle wall forms the lateral boundary of the working corridor
• Warning: The medial pedicle wall is the boundary of the spinal canal — thin it with a diamond burr and remove the remaining cortex with a Kerrison rongeur or curette to expose the lateral spinal canal

Step 3: Identify the Herniation

• With the pedicle window open, identify the lateral border of the spinal cord / thecal sac
• The disc space is just anterior to the plane of the pedicle — a blunt nerve hook or dental probe can palpate the disc space
• The herniated disc material is identified as soft or calcified tissue protruding into the lateral recess

Step 4: Discectomy

• Using a nerve hook or micro-dissector, gently mobilise the herniated disc material BACK toward the surgeon (away from the cord) — the instrument tip must never push material toward the cord
• Use small pituitary rongeurs and micro-curettes to resect the herniated fragment and adjacent disc material
• The cardinal rule: If any instrument or retractor must contact the spinal cord to visualise or resect the herniation, convert to a more extensile approach (costotransversectomy or transthoracic)
• Limit annular resection to the herniated quadrant — the disc space is intact and the annulus provides anterior stability

Step 5: Verify Decompression

• Inspect the lateral cord and nerve root — they should be free and pulsatile
• Use a blunt nerve hook to confirm that the disc space is decompressed laterally
• Confirm MEP and SSEP recordings remain stable or have improved from baseline
• If the herniation is central and cannot be fully resected through this window, proceed to costotransversectomy or close and convert to a transthoracic approach

Step 6: Closure

• Layered closure of deep fascia (absorbable), subcutaneous tissue and skin
• No drain required for the transpedicular approach if haemostasis is satisfactory
• The facetectomy defect does not routinely require stabilisation unless bilateral facetectomy or significant resection has been performed

Costotransversectomy Approach — Step-by-Step

Indication

Central-lateral thoracic disc herniation where a wider lateral angle is needed than the transpedicular window provides.

Step 1: Incision and Exposure

• Midline or paramedian incision (2-3 cm lateral to midline on the side of the herniation) over the index level
• Subperiosteal dissection to expose the transverse process and the medial 5-6 cm of the rib at the index level
• Confirm the level with intraoperative radiography or navigation

Step 2: Costotransversectomy

• Resect the transverse process using a rongeur (bone cutter or Kerrison)
• Resect the medial 3-4 cm of the rib (including the rib head) using a rib cutter or rongeur — the rib periosteum is elevated circumferentially before resection to protect the pleura and intercostal neurovascular bundle
• Warning: The intercostal neurovascular bundle runs in the subcostal groove on the INFERIOR surface of the rib — dissect on the SUPERIOR surface of the rib when elevating periosteum
• Remove the rib head and the costotransverse ligament to expose the lateral vertebral body and pedicle
• The pleura lies immediately anterior and inferior to the rib bed — if the pleura is violated, repair it primarily with a 4-0 absorbable suture or apply a sealant

Step 3: Pediculotomy

• Identify the pedicle at the level of the herniation and the pedicle above
• Resect the pedicle of the LEVEL ABOVE the disc space (i.e., if the herniation is at T7-T8, resect the T7 pedicle) — this opens a window into the posterior disc space
• Use a combination of high-speed burr, Kerrison rongeur and curette to create a window approximately 10-12 mm wide

Step 4: Discectomy

• The working angle is now more lateral than the transpedicular approach — the disc space is approached from the costotransverse defect
• Use micro-curettes and pituitary rongeurs to resect the herniated disc fragment, working from lateral to medial
• A 45-degree or 90-degree angled curette is helpful for reaching across the midline
• NEVER retract the spinal cord — if the midline disc fragment is not accessible from this angle, convert to an anterior approach
• For a broad-based or calcified disc, the costotransversectomy may still provide insufficient access — the surgeon must have a low threshold to convert

Step 5: Closure

• Check for pleural violation — if present, repair and place a small chest tube (20-24 Fr) with underwater seal
• If pleura intact, layered wound closure over a suction drain (15 Fr, placed deep to the muscle layer, exiting laterally through a separate stab incision)
• Intercostal nerve block at the level of resection for postoperative analgesia

Transthoracic (Anterior Transpleural) Approach — Step-by-Step

Indication

Central, broad-based, or calcified thoracic disc herniation where direct anterior visualisation of the ventral cord is required.

Step 1: Incision and Chest Entry

• Level-dependent incision: For T4-T10, a posterolateral thoracotomy through the intercostal space at the level of the disc or one level above (the rib crosses at the pedicle level — entering one level above provides access to the disc)
  • T4-T5: Right-sided thoracotomy (to avoid the heart, aorta and thoracic duct)
  • T6-T10: Side of approach determined by herniation location (usually right for central discs; left if the herniation is asymmetrically left-sided, but with preoperative CTA to map Adamkiewicz)
  • T11-T12: Consider thoracoabdominal incision with diaphragmatic detachment
• Divide the latissimus dorsi, serratus anterior and intercostal muscles in the line of the incision
• Enter the pleural space — deflate the ipsilateral lung

Step 2: Rib Resection

• Resect the rib at the level of the incision (usually the rib ABOVE the disc space) — removing 4-6 cm of rib posterior to the costochondral junction provides the exposure
• The rib is resected subperiosteally to protect the intercostal neurovascular bundle and pleura
• Place a rib spreader (Finochietto or Tuffier retractor) and open gradually to avoid rib fracture

Step 3: Identify and Mobilise the Segmental Vessels

• The lung is retracted anteriorly (covered with a moist lap sponge)
• Identify the segmental vessels overlying the lateral vertebral body — the intercostal/segmental artery and vein run transversely across the mid-vertebral body
• The aorta lies on the left side of the vertebral bodies, the azygos/hemiazygos vein on the right — palpate and protect them
• Palpate the disc space and confirm the level by intraoperative radiography or navigation (a spinal needle placed into the disc is the most reliable method)
• Ligate the segmental vessels at the level of the disc AND one level above and below — ligate away from the aorta (not at the aorta) to avoid aortic injury. Use surgical clips or silk ties, dividing the vessels 5-10 mm from the aorta on the left or from the azygos vein on the right
• Critical warning: If the preoperative CTA/MRA has identified the artery of Adamkiewicz arising at or adjacent to the herniation level, do NOT ligate that segmental vessel — consider a temporary occlusion trial with neuromonitoring or choose a different approach

Step 4: Partial Vertebrectomy (Corpectomy Window)

• Mark the disc space and the adjacent vertebral body margins on each side — verify with a spinal needle and X-ray
• Using a high-speed burr (4-5 mm cutting burr followed by diamond burr at the posterior vertebral cortex), create a trough in the vertebral body approximately 15-18 mm wide and extending from the endplate above the disc to the endplate below
• Resect the POSTERIOR portion of the vertebral bodies above and below the disc — this creates the working window through which the disc and posterior longitudinal ligament (PLL) are approached
• Depth control: Preserve a thin shell of posterior vertebral cortex until the final step — the diamond burr is used to feather the posterior cortex down to a paper-thin layer before removal

Step 5: Discectomy and Decompression

• The critical manoeuvre: The disc is now approached from ANTERIOR to the spinal cord. The herniated material is resected TOWARD the surgeon, AWAY from the cord
• Remove the disc material using micro-curettes, pituitary rongeurs and angled dissectors — work from anterior to posterior
• Remove the posterior longitudinal ligament (PLL) with a micro-hook or Kerrison rongeur — this exposes the ventral dura
• For a calcified disc that is adherent to the dura:
  • Plan for an intentional durotomy — resect the calcified disc and adherent dura en bloc
  • Use a diamond burr to thin the calcified mass before dissection
  • The dural defect is repaired primarily (6-0 Prolene or Gore-Tex) or with a patch (autologous fascia, bovine pericardium, dural substitute)
  • Apply fibrin glue or sealant over the repair
• Verify complete decompression — the ventral dura should be visible and pulsatile across the full width of the canal to the opposite pedicle

Step 6: Closure

• Achieve meticulous haemostasis — use bone wax for the vertebral body cancellous bone, bipolar cautery and haemostatic matrix for epidural vessels
• The corpectomy defect does not routinely require reconstruction with cage/graft if a single-level discectomy has been performed and the endplates are intact (controversial — some surgeons place a structural graft to prevent kyphosis)
• If reconstruction is performed, use an iliac crest autograft, rib autograft or a titanium cage packed with autograft — placed under compression
• Pleural closure: Close the pleura over the spine with a running absorbable suture, making it water-tight. If the pleura cannot be closed, a pleural flap or pericardial fat graft can be used
• Chest tube: Place a 24-28 Fr chest tube through a separate stab incision, positioned to drain the posterior pleural space — connect to underwater seal at -20 cm H2O suction
• Re-inflate the lung under direct vision — confirm full expansion
• Closed suction drain in the muscle layer (if desired)
• Intercostal nerve block (bupivacaine 0.25-0.5%) for postoperative pain control: inject 2-3 mL per intercostal space, two levels above and below the incision
• Layered closure: ribs approximated with heavy absorbable sutures (No. 1 PDS or Vicryl) or rib-closure device; muscle layers closed with absorbable sutures; skin closure

Lateral Extracavitary Approach — Step-by-Step (Summary)

Indication

Central, calcified or revision discs where a ventral approach is needed but transthoracic access is undesirable (pleural adhesions, thoracolumbar junction, need to avoid lung deflation).

Key Technique Points

• Position: Prone or three-quarter prone with the herniation side elevated
• Incision: A curved paramedian incision (5-6 cm lateral to midline) or a large midline flap raised and retracted laterally — the extent of skin and muscle mobilisation is significantly greater than costotransversectomy
• Exposure: The paraspinal muscles (longissimus, iliocostalis) are mobilised medially or divided to expose the transverse processes and ribs over 2-3 levels
• Bone resection: Transverse process resection and medial rib resection (similar to costotransversectomy) but more extensive — typically 5-6 cm of rib resected, allowing the pleura to be bluntly dissected from the lateral vertebral body
• Retropleural dissection: The pleura is swept ANTERIORLY off the vertebral body using blunt dissection and Kittner dissectors — this creates a working channel anterior to the cord WITHOUT entering the pleural cavity
• Segmental vessel management: The segmental vessels are identified, ligated and divided (with same Adamkiewicz precautions)
• Discectomy: Through a lateral vertebrectomy window, identical in principle to the transthoracic approach — the disc is resected from lateral/anterior to posterior toward the surgeon
• Closure: If the pleura is intact, no chest tube is required. If violated, repair and place a chest tube. Deep suction drain in the retropleural cavity

Post-operative Protocol

Immediate Post-operative (Day 0-1)

All approaches:

• Neurovascular observations every hour for 24 hours (motor power, sensory level, lower limb reflexes, anal tone/bladder function)
• MEP/SSEP monitoring may be continued for 12-24 hours if there is concern about cord perfusion
• MAP maintained greater than 80 mmHg for first 24 hours — avoid hypotension which reduces spinal cord perfusion
• Analgesia: multimodal (paracetamol, NSAIDs if no contraindication, PCA morphine or fentanyl for major approaches; consider gabapentinoid for neuropathic component)
• Antiemetics and laxatives (opioid-induced constipation prophylaxis)

Transthoracic approach-specific:

• Chest tube to underwater seal at -20 cm H2O suction
• CXR immediately post-operatively to confirm lung expansion and chest tube position
• Chest tube output charted hourly — if greater than 200 mL/hour for 3 consecutive hours, notify the surgeon
• Incentive spirometry — 10 breaths every hour while awake
• Keep the patient nil by mouth until bowel sounds return (ileus common after thoracotomy)
• Remove chest tube when output less than 100-150 mL/24 hours, no air leak on water seal trial, and CXR confirms full lung expansion

Early Phase (Day 1-3)

All approaches:

• Mobilise with physiotherapy from day 1 if neurologically stable — out of bed to chair, then ambulation with assistance
• Urinary catheter removed once the patient is mobile
• Bowel care: stool softeners, laxatives as needed
• Wound check daily for drainage, erythema, or signs of infection
• Deep vein thrombosis prophylaxis: mechanical (sequential compression devices) from day 0; chemical (enoxaparin) from day 1 if no contraindication and no intraoperative dural tear

Transthoracic-specific:

• Chest tube management: water seal trial when output less than 150 mL/24 hours and no air leak for 24 hours
• Respiratory therapy: incentive spirometry, deep breathing and coughing exercises
• Intercostal catheter analgesia if placed

Intermediate Phase (Day 4-14)

• Sutures/staples removed at 10-14 days for posterior approaches; 14 days for transthoracic (longer due to respiratory motion stress on the wound)
• No lifting greater than 5 kg, no bending or twisting for 6 weeks
• Wound care: keep dry until suture removal; showering allowed after 48 hours if wound is sealed
• Driving: not recommended for 4-6 weeks (risk of sudden pain or weakness causing loss of control)
• Return to work: sedentary/desk work at 4-6 weeks; manual work at 12-16 weeks (approach and patient-dependent)

Long-term (6 Weeks to 12 Months)

• Physiotherapy: core strengthening, postural retraining, lower limb strengthening if any residual weakness
• Return to sport: low-impact (swimming, cycling) at 3 months; contact sports at 6-12 months (approach and surgeon preference)
• Radiographic follow-up: standing AP and lateral at 6 weeks, 3 months and 12 months to assess alignment, fusion (if grafted) and adjacent level degeneration
• MRI: only if new symptoms develop or if there is concern about incomplete decompression or recurrence

Special Case: Calcified Thoracic Discs

Why They Are Different

• Calcified discs represent a chronic, often ossified process where the disc material has undergone metaplastic bone formation within the annulus and nucleus
• The calcified mass may be densely adherent to, or actually penetrate, the ventral dura — intradural extension occurs in a small but significant proportion (up to 5% of calcified discs)
• Dural tears during resection of calcified discs are common — reported rates of 15-30% in series (Stillerman)

Preoperative Preparation

• Mandatory CT: All thoracic disc herniations require a preoperative CT to assess for calcification. If the disc is hyperdense (Hounsfield units greater than 200), plan for an anterior approach
• Consent: Specifically counsel the patient about the elevated risk of dural tear, CSF leak, intentional durotomy and the possibility of dural patch repair
• MRI with thin-slice T2: Evaluate the interface between the disc and the ventral dura — a lack of the normal CSF cleft between disc and dura raises suspicion for dural adhesion
• Arrange lumbar drain: For high-risk cases, preoperative lumbar drain placement allows CSF diversion to reduce pressure on the dural repair postoperatively

Intraoperative Strategy

• Approach choice: Transthoracic or lateral extracavitary — NEVER a posterolateral approach for a calcified disc. Direct anterior visualisation of the disc-dura interface is essential
• Dural separation: Use a diamond burr to thin the calcified mass from the vertebral body side until a thin eggshell layer remains adjacent to the dura — this layer is then gently dissected off the dura with a micro-dissector
• Intradural extension: If the disc has penetrated the dura, plan for an intentional durotomy. Open the dura 2-3 mm around the adherent disc, resect the disc and the involved dura en bloc
• Dural repair: Primary closure with 6-0 Prolene or Gore-Tex suture. If the defect is larger than 5 mm or the dura is friable, use a patch (autologous fascia lata, bovine pericardium, artificial dural graft). Suture the patch in a water-tight fashion
• Sealant: Apply fibrin glue over the repair
• Drain management: If a dural repair has been performed, consider a lumbar drain (CSF output 10-15 mL/hour) for 3-5 days to reduce pressure on the repair

Special Case: Intradural Disc Herniation

Rare but High-Risk

• Intradural thoracic disc herniation is rare (less than 5% of all thoracic disc herniations) but carries a high risk of neurological deficit if not recognised preoperatively
• Most intradural herniations are calcified or densely adherent to the ventral dura
• The MRI hallmark: absence of a clear CSF cleft between the disc and the cord on the side of the herniation; the disc appears to be within the thecal sac

Surgical Management

• Anterior (transthoracic) approach is mandatory — provides the best access for dural opening and repair
• Plan for intentional durotomy and en-bloc resection
• After dural repair, place a lumbar drain for 3-5 days
• Counsel the patient preoperatively about the elevated risk of transient or permanent neurological deficit, CSF leak and the need for prolonged lumbar drainage

Special Case: Upper Thoracic Disc (T1-T4)

Technical Challenges

• The shoulders, sternum and great vessels limit anterior access to the upper thoracic spine
• The spinal cord occupies the highest proportion of the canal in this region — less reserve space
• The thoracic kyphosis is most pronounced in the upper thoracic region

Approach Options

• Posterolateral (costotransversectomy): The preferred approach for T1-T4 disc herniations — the ribs are shorter and the transverse processes are more accessible
• Transpedicular approach: Feasible for lateral discs at T1-T2
• Trans-sternal / manubriotomy approach: Rarely needed — reserved for central/calcified discs at T1-T4 that cannot be safely reached posterolaterally. This is a major procedure requiring a cardiothoracic surgeon and sternal splitting
• Suprasternal (anterior cervical) approach for T1-T2: Can be performed as an extension of a low anterior cervical approach for T1-T2 discs