import { OnePagerSummary, ContentSection, SafetyAlert, ComparisonTable, EvidenceCard, VivaScenarioSection, VivaScenario, MnemonicCard, ExamCheatSheet, InfoCard, InfoCardGrid, ExamWarning } from '@/components/mdx' {/* SECTION 1: ONE-PAGER SUMMARY */} {/* SECTION 2: EXAM WARNING */} **Most feared complication.** RLN injury causes **hoarseness** (vocal cord paralysis). Runs in **tracheoesophageal groove**. LEFT side has predictable course (enters larynx at cricoid), RIGHT side loops around subclavian (variable). Injury rate: **2-5% transient, 0.2% permanent**. Caused by: prolonged retraction, electrocautery, direct trauma. **Left side preferred in 95% of cases.** RLN on left has **consistent recurrent course** from mediastinum. On right, RLN can have **non-recurrent course** (loops around subclavian artery) in 0.5-1% of patients. Surgeons operate from their preferred side for familiarity, but left is anatomically safer. **Catastrophic complication** (0.1-0.3% incidence). Causes: direct trauma during dissection, electrocautery, retractor pressure. Presents with **dysphagia, fever, neck swelling, mediastinitis**. Requires immediate repair and drainage. Prevention: gentle retraction, identify esophagus before retractor placement, use handheld retractor initially. **Surgical emergency** (0.3% incidence). VA runs in **foramen transversarium** (lateral to vertebral body). Injury causes: lateral dissection beyond uncinate process, lateral screw placement, excessive lateral retractor. Prevention: **stay midline**, identify midline via longus colli muscles, limit lateral dissection to 15mm from midline. {/* SECTION 3: QUICK DECISION GUIDE */} {/* SECTION 4: SURGICAL ANATOMY */} ### Surface Landmarks and Level Identification **Critical landmarks for level localization:** The **cricoid cartilage** is palpable at the **C6 vertebral level** - this is the single most important surface landmark. The **hyoid bone** sits at C3 level, and the **thyroid cartilage** (Adam's apple) at C4-5. The **carotid tubercle** (Chassaignac tubercle) is a bony prominence on the anterior aspect of the C6 transverse process, palpable 1-2cm lateral to the cricoid - this is where you compress the carotid artery during carotid massage. **Intraoperative level confirmation:** Always obtain a lateral C-spine X-ray with a **radiopaque marker** (needle or instrument) placed on the disc space BEFORE making the discectomy. Counting from C2 (easily identified as the first vertebra below the skull base on lateral X-ray) prevents wrong-level surgery. C7 is also easily identified as the first vertebra with a large spinous process (vertebra prominens) and no anterior tubercle on the transverse process. ### Layer-by-Layer Anatomy **Skin and subcutaneous tissue:** The skin incision follows **Langer's lines** (natural skin creases) for optimal cosmetic outcome. A **transverse incision** is used for 1-2 level surgery, placed in a skin crease at the appropriate level (e.g., cricoid level for C5-6). For multilevel surgery (3+ levels), a **longitudinal incision** along the medial border of SCM provides extensile exposure. **Platysma muscle:** The **platysma** is a thin muscle layer immediately deep to subcutaneous fat. It is incised in line with the skin incision. The **anterior jugular veins** run deep to platysma in the midline - identify and ligate or cauterize if necessary (usually can be retracted). **Deep cervical fascia - three layers:** 1. **Superficial layer** (investing fascia): encases SCM and trapezius muscles 2. **Middle layer** (pretracheal fascia): surrounds trachea, esophagus, thyroid 3. **Deep layer** (prevertebral fascia): covers vertebral bodies and longus colli muscles (this is the target layer) The **natural plane** for dissection is between the middle and deep layers of deep cervical fascia. This plane is developed **medial to the carotid sheath** and **lateral to the trachea/esophagus**. ### Carotid Sheath Contents The carotid sheath contains three critical structures (remembered as "VAN" from lateral to medial): 1. **Internal jugular Vein** (most lateral) 2. **common carotid Artery** (middle) 3. **vagus Nerve** (most medial, in tracheoesophageal groove) The carotid sheath is **retracted LATERALLY** during the approach. The **carotid pulse** is palpable and helps identify the sheath location. The sheath is retracted as a unit - do not dissect individual structures within it. ### Recurrent Laryngeal Nerve (RLN) - Critical Anatomy **Left RLN course (consistent in 99.5% of patients):** The left RLN branches from the **vagus nerve** in the superior mediastinum, loops under the **aortic arch** (at the ligamentum arteriosum), and ascends in the **tracheoesophageal groove** to enter the larynx at the level of the **cricoid cartilage** (C6). This course is predictable and relatively protected during left-sided approach. **Right RLN course (variable):** The right RLN branches from the vagus and loops under the **right subclavian artery** before ascending in the tracheoesophageal groove. However, in **0.5-1% of patients**, the right RLN has a **non-recurrent course** - it branches from the vagus at the C6 level and runs directly to the larynx WITHOUT descending into the chest. This non-recurrent RLN is at HIGH risk of injury during right-sided approach because it crosses the surgical field at the disc level. **RLN injury mechanisms:** 1. **Prolonged retraction** (most common cause): use handheld retractor initially, limit retractor pressure, release retraction every 30 minutes 2. **Direct trauma**: excessive medial dissection into tracheoesophageal groove 3. **Electrocautery**: thermal injury from cautery near tracheoesophageal groove 4. **Endotracheal tube cuff overinflation**: causes tracheal distension pushing RLN into surgical field **Clinical presentation of RLN injury:** **Unilateral RLN palsy** causes hoarseness (vocal cord paralysis in paramedian position), weak voice, difficulty with high-pitched sounds, aspiration risk (especially with liquids). **Bilateral RLN palsy** causes airway obstruction (both cords in paramedian position) and may require emergency tracheostomy. ### Esophagus The **esophagus** lies posterior to the trachea and anterior to the prevertebral fascia (vertebral bodies). It is **retracted MEDIALLY** along with the trachea during the approach. The esophagus is a **collapsible muscular tube** without serosal layer - this makes it vulnerable to injury from retractor pressure (unlike bowel which has serosa). **Esophageal deviation:** The esophagus deviates to the **LEFT side of the midline** in 60% of patients at the cervical level. This makes left-sided approach slightly easier (esophagus naturally away from field). On right-sided approach, the esophagus may need to be mobilized more to retract medially. **Nasogastric tube (NGT) placement:** Some surgeons place an NGT before surgery to **palpate the esophagus** and aid identification. Others avoid NGT because it stiffens the esophagus and may increase perforation risk. Neither approach is clearly superior. ### Superior and Inferior Thyroid Arteries The **superior thyroid artery** (branch of external carotid) descends to the thyroid gland and crosses the surgical field at the **C3-4 level**. It may require **ligation** for exposure at high cervical levels. The **inferior thyroid artery** (branch of thyrocervical trunk from subclavian) ascends to the thyroid and crosses at the **C6-7 level**. The RLN has a close relationship with the inferior thyroid artery (passes behind, in front, or between its branches). ### Superior Laryngeal Nerve The **external branch of the superior laryngeal nerve** descends on the inferior pharyngeal constrictor muscle and innervates the **cricothyroid muscle**. It is at risk during dissection at **C3-4 level** (high cervical exposure). **Injury** causes inability to tense the vocal cords (cricothyroid muscle paralysis), resulting in **low-pitched, hoarse voice** and **inability to sing or shout** (loss of high-frequency range). This is distinct from RLN injury which causes breathy, weak voice. ### Sympathetic Chain The **cervical sympathetic chain** runs on the **longus colli muscle** beneath the prevertebral fascia. It is typically lateral enough to avoid injury, but excessive lateral dissection or retraction can injure it. **Horner syndrome** results from sympathetic chain injury: **miosis** (pupil constriction), **ptosis** (eyelid drooping), **anhidrosis** (loss of sweating on ipsilateral face). This is usually temporary but can be permanent. ### Longus Colli Muscles The **longus colli muscles** are paired muscles that run along the anterolateral aspect of the vertebral bodies from C1 to T3. They mark the **lateral extent of safe dissection** - staying medial to the longus colli protects the vertebral artery. **Surgical technique:** The longus colli muscles are **elevated subperiosteally** off the vertebral bodies **bilaterally** (15-20mm from midline on each side). Self-retaining retractors (Caspar or similar) are placed UNDER the longus colli to retract soft tissues laterally. This technique protects the sympathetic chain (which runs on top of longus colli) and prevents retractor migration medially toward esophagus. ### Vertebral Artery The **vertebral artery** enters the **foramen transversarium at C6** (sometimes C7 or C5) and ascends through the transverse foramina to C1, then passes posteriorly to enter the foramen magnum. It lies **15-20mm lateral to the midline** at the vertebral body level. **Protection:** Staying **medial to the uncinate process** (posterolateral lip of vertebral body) protects the vertebral artery. The uncinates are palpable as bony ridges at the lateral edge of the vertebral body. **Lateral dissection should not exceed 15mm from the midline.** **Injury:** Vertebral artery injury occurs from: lateral dissection beyond uncinate, laterally placed screws, aggressive lateral osteophyte removal, lateral retractor placement. It presents as **sudden bleeding** (venous bleeding initially as VA has venous plexus around it, then arterial). Management: pack field, obtain vascular surgery consult, may require ligation (usually tolerated if contralateral VA intact). ### Spinal Cord and Nerve Roots The **spinal cord** extends from the foramen magnum to L1-2 level (conus medullaris). In the cervical spine, the cord is **elliptical** in cross-section (wider transversely) and occupies about 50% of the spinal canal diameter (leaving minimal reserve space - this is why cervical myelopathy develops from stenosis). **Nerve roots:** Cervical nerve roots exit **above** the correspondingly numbered vertebra (C5 root exits between C4-5, C6 root between C5-6, etc.). The **C8 root** exits between C7-T1 (there is no C8 vertebra). Starting at T1, thoracic roots exit **below** the correspondingly numbered vertebra. **Nerve root anatomy at disc level:** During ACDF, the nerve root is located **posterolateral** to the disc space. Complete discectomy to the posterior longitudinal ligament (PLL) is performed, then PLL is excised to expose the **dura** centrally. The nerve root is seen **exiting laterally** under the uncinate process. Adequate decompression requires removing posterior osteophytes and uncovertebral joint if foraminal stenosis present. {/* SECTION 5: INDICATIONS AND CONTRAINDICATIONS */} ### Indications **1. Cervical radiculopathy (most common indication - 60% of cases):** Arm pain in dermatomal distribution due to nerve root compression from **disc herniation** or **foraminal stenosis** (uncovertebral joint osteophytes). Surgery indicated after 6-12 weeks of conservative management (physical therapy, NSAIDs, epidural steroid injection) if persistent symptoms or progressive neurological deficit. **Imaging correlation required:** MRI showing disc herniation or foraminal stenosis at level corresponding to clinical symptoms. Myelopathy signs (gait instability, hand clumsiness, hyperreflexia) suggest cord compression requiring more urgent intervention. **2. Cervical myelopathy (20% of cases):** Spinal cord compression causing **progressive neurological dysfunction**: hand clumsiness (difficulty with buttons, dropping objects), gait instability, bladder urgency, hyperreflexia, Hoffman sign, Babinski sign. **Nurick grade** assesses myelopathy severity (0 = signs only, 5 = wheelchair-bound). **Natural history:** Progressive in 75% of patients. **Surgery is the only treatment** that halts progression and may provide improvement (especially if mild-moderate myelopathy). Conservative management leads to stepwise deterioration. **3. Cervical spine trauma (10% of cases):** **Facet dislocation** (unilateral or bilateral): anterior approach allows disc removal before reduction (prevents disc herniation into canal during reduction), then ACDF for stability. **Vertebral body fracture** (burst fracture, teardrop fracture): corpectomy and reconstruction if significant canal compromise or instability. **Odontoid fracture Type II** (via extended Smith-Robinson to C2-3 level): anterior odontoid screw fixation for Type II fractures in young patients with favorable anatomy. **4. Tumor (5% of cases):** **Vertebral body metastasis** with pathological fracture or cord compression: corpectomy and reconstruction (methylmethacrylate cage or expandable cage) for palliation and neurological preservation. **Primary bone tumor** (rare): en-bloc spondylectomy via anterior approach (often combined with posterior). **5. Infection (less than 5% of cases):** **Discitis/osteomyelitis** unresponsive to antibiotics or with neurological compromise: anterior debridement, fusion with autograft (rib or iliac crest), NO instrumentation initially (add plate after infection controlled if needed). ### Contraindications **Absolute:** 1. **Active infection at surgical site** (cervical soft tissue abscess) - defer until treated 2. **Severe medical comorbidity** preventing general anesthesia 3. **Posterior pathology only** (ligamentum flavum hypertrophy without anterior compression) - use posterior approach **Relative:** 1. **Prior anterior neck surgery** (increases scar tissue, adhesions, risk of RLN injury and esophageal injury) - consider posterior approach 2. **Prior neck radiation** (for head/neck cancer) - tissue quality poor, healing impaired, higher complication rate 3. **Ankylosing spondylitis** with fused spine - anterior osteotomy carries high fracture risk 4. **Severe COPD** - retraction of trachea may compromise airway 5. **Morbid obesity** - technical difficulty with exposure and retraction 6. **Multilevel disease** (4+ levels) - consider posterior approach or combined approach (dysphagia and pseudarthrosis risk increase with multilevel anterior) ### Special Considerations - Australian Context **Medicare coverage:** Anterior cervical discectomy and fusion (ACDF) is covered by Medicare for **radiculopathy or myelopathy with imaging correlation**. Cervical disc arthroplasty (motion-preserving) has limited coverage and may require private health insurance. Multilevel fusions (3+ levels) require documentation of failed conservative management and appropriate imaging. **Return to work:** WorkCover guidelines suggest **6-12 weeks** for sedentary office work (computer use, desk work), **3-6 months** for manual labor (depending on fusion status and occupation). Early mobilization protocols (walking day 1, cervical collar for comfort only 1-2 weeks) improve return-to-work rates. Occupation-specific therapy (simulating work tasks) helps transition back to heavy labor. **Driving:** Patients can resume driving when **off opioid medications** and able to turn head comfortably (check blind spots). Typically **2-4 weeks** for single-level ACDF, longer for multilevel. **Smoking cessation:** **Smoking increases pseudarthrosis (non-union) risk from 5% to 20-30%** in ACDF. **Quitline 13 7848** provides free telephone counseling. Surgeons should document smoking cessation counseling and consider nicotine testing before elective surgery. Some surgeons defer elective ACDF until 6-8 weeks of smoking cessation achieved. {/* SECTION 6: PATIENT POSITIONING */} ### Standard Positioning **Supine position** on radiolucent operating table with: 1. **Shoulder roll** (small towel/gel roll) placed transversely between scapulae to extend neck and improve anterior exposure 2. **Head ring** or **horseshoe headrest** to maintain neutral head position (slight extension acceptable) 3. **Arms tucked at sides** with padding at elbows (ulnar nerve protection) 4. **Tape across forehead** to secure head (prevents rotation during surgery) 5. **Tape across shoulders** pulling caudally to aid fluoroscopy visualization of lower cervical levels (C6-7, C7-T1) ### Alternative: Mayfield Tong Some surgeons prefer **Mayfield tongs** (3-pin skull fixation) for: 1. **Multilevel cases** (better control of head position during long case) 2. **Revision surgery** (more stable positioning) 3. **Corpectomy** (allows gentle extension to open anterior disc spaces) **Advantage:** Rigid head fixation prevents movement during surgery **Disadvantage:** Pin site complications (scalp laceration, infection), slightly longer setup time ### Lateral Fluoroscopy **C-arm fluoroscopy** positioned on the patient's RIGHT side (opposite the surgeon who stands on left for left-sided approach). This allows: 1. **True lateral** cervical spine images during case 2. **Level confirmation** before discectomy (marker placed on disc) 3. **Real-time screw trajectory** visualization during plate application 4. **Final construct** assessment before closing Ensure true lateral positioning (spinous processes aligned, no rotation) before starting case. ### Neck Preparation and Draping **Skin preparation:** Prep from **mandible to upper chest** and laterally to include SCM muscle on the operative side. Use **chlorhexidine or iodine** prep solution. Allow adequate drying time (reduces infection risk). **Draping:** Use **split sheets** or **U-drape** to create sterile field. Expose the **SCM muscle** and **midline structures** (thyroid cartilage, cricoid cartilage). Some surgeons place **sterile towel under neck** to accentuate extension and improve exposure. ### Endotracheal Tube Considerations **Standard endotracheal tube** vs **reinforced tube:** Most surgeons use **standard ETT**. Some prefer **reinforced (armored) tube** to prevent kinking from retractor pressure. There is **no evidence** that tube type affects RLN injury rate. **Cuff pressure monitoring:** Use **manometer** to monitor ETT cuff pressure throughout case. Keep pressure at **20-25 cm H2O** (not higher). Overinflation causes tracheal distension, pushing RLN into surgical field and increasing injury risk. Release and re-inflate cuff if pressure rises above 30 cm H2O. **Nasogastric tube (NGT):** Controversial. Some place NGT to **aid esophageal identification** via palpation. Others avoid NGT because it stiffens esophagus and may increase perforation risk. **No consensus** - surgeon preference. {/* SECTION 7: SURGICAL APPROACH - STEP BY STEP */} ### Step 1: Skin Incision and Platysma **Transverse incision** (for 1-2 levels): Identify the appropriate level via palpation of cricoid cartilage (C6). Make a **transverse skin incision** along Langer's lines (skin crease) at the target level. Incision length: **3-4cm for single level, 5-6cm for two levels**. Position incision **slightly off midline** toward the operative side (usually left). **Incise skin and subcutaneous tissue** to platysma muscle. **Inject local anesthetic with epinephrine** (0.25% marcaine with 1:200,000 epinephrine) into subcutaneous tissues for hemostasis and postoperative pain control. **Incise platysma** in line with skin incision. Identify and **cauterize anterior jugular veins** if encountered (usually can be retracted). Develop subplatysmal flaps superiorly and inferiorly for 1-2cm to improve exposure. ### Step 2: Identify SCM Lateral Border **Palpate the medial border of SCM muscle.** This is the key landmark. The dissection plane will be **medial to SCM** (between SCM and midline structures). **Incise the superficial layer of deep cervical fascia** along the medial border of SCM. This opens the natural plane between: - **Lateral:** Carotid sheath (within SCM fascia) - **Medial:** Trachea and esophagus (within pretracheal fascia) **Blunt dissection** with finger or Kittner dissector develops this plane. The plane should open easily with minimal resistance - if you encounter resistance, you may be in wrong plane (too lateral into carotid sheath, or too medial into visceral structures). ### Step 3: Identify and Retract Carotid Sheath Laterally **Palpate the carotid pulse.** The carotid sheath is a distinct tubular structure containing the common carotid artery, internal jugular vein, and vagus nerve. **Retract the carotid sheath LATERALLY** using a handheld Richardson or Deaver retractor. Do NOT dissect individual structures within the sheath - retract the entire sheath as a unit. **Warning:** Avoid excessive lateral retraction (causes vagal stimulation and bradycardia). If heart rate drops, release retraction briefly. ### Step 4: Identify Midline Structures and Retract Medially **Palpate the trachea** - it is a firm, tubular structure in the midline. The **thyroid gland** overlies the trachea at C5-7 level - it may need to be mobilized superiorly or inferiorly depending on operative level. **The omohyoid muscle** crosses the field obliquely in some patients - it can be retracted or divided (minimal morbidity). **Identify the esophagus** posterior to the trachea via palpation (softer, collapsible compared to trachea). If NGT is placed, it aids palpation. **Retract trachea and esophagus MEDIALLY** using a handheld retractor (Richardson or Army-Navy). Use **gentle retraction** - the RLN is in the tracheoesophageal groove and excessive pressure causes injury. ### Step 5: Expose Prevertebral Fascia With the carotid sheath retracted laterally and midline structures retracted medially, the **prevertebral fascia** comes into view. This is a thin, glistening fascial layer covering the anterior vertebral bodies and longus colli muscles. **Palpate the anterior vertebral bodies** through the prevertebral fascia. The disc spaces are palpable as **soft depressions** between the **firm vertebral bodies**. The **anterior longitudinal ligament** runs vertically as a taut band in the midline. **Confirm the operative level** using **lateral fluoroscopy with a radiopaque marker** (spinal needle or instrument) placed on the presumed disc space. This step is **MANDATORY** before any bone or disc work to prevent wrong-level surgery. ### Step 6: Incise Prevertebral Fascia Once the correct level is confirmed, **incise the prevertebral fascia** over the disc space and adjacent vertebral bodies using **electrocautery or scalpel**. **Identify the longus colli muscles** - they appear as paired muscles running along the anterolateral aspect of the vertebral bodies, 5-10mm lateral to the midline on each side. **Cauterize or ligate small vessels** on the anterior vertebral body (anterior venous plexus). Maintain meticulous hemostasis to improve visualization. ### Step 7: Elevate Longus Colli Muscles Bilaterally **Elevate the longus colli muscles** bilaterally off the vertebral bodies using **Cobb elevator or periosteal elevator**. **Technique:** Start at the midline and work laterally. Elevate the muscle **subperiosteally** (keeping periosteum with muscle) for **15-20mm lateral to midline** on each side. Stay **medial to the uncinate process** (lateral bony ridge of vertebral body) to protect the vertebral artery. **Do NOT extend elevation superiorly above or inferiorly below** the levels to be operated (limits soft tissue stripping and preserves blood supply). ### Step 8: Place Self-Retaining Retractors **Place Caspar pin retractors** or similar self-retaining system: 1. **Pins are inserted** into the vertebral bodies above and below the disc space (angled 15-20° caudally to avoid endplate violation) 2. **Attach distraction posts** to pins and apply gentle distraction (opens disc space for visualization) 3. **Place handheld retractors UNDER the longus colli muscles** bilaterally (toothed retractors or blades) 4. **Attach retractor blades to Caspar frame** **Key principle:** Retractors placed **under longus colli** (not on top) protect the sympathetic chain and esophagus. The retractors sit on the lateral vertebral body and retract longus colli and all soft tissues laterally. **Check retractor position:** The medial edge should be at the midline (or slightly medial), the lateral edge should NOT extend beyond the uncinate process. **Release retraction every 30 minutes** during long cases to reduce RLN injury risk from prolonged pressure. ### Step 9: Perform Discectomy **Remove the disc:** This is now an orthopedic procedure on exposed bone and disc. 1. **Score the annulus** with scalpel or electrocautery 2. **Remove annulus** with pituitary rongeurs 3. **Remove nucleus pulposus** with curettes and rongeurs 4. **Remove cartilaginous endplates** with curettes (down to bleeding subchondral bone) 5. **Remove posterior osteophytes** with Kerrison rongeurs or burr 6. **Incise posterior longitudinal ligament** to expose dura **Complete decompression** requires disc removal from uncinate to uncinate laterally, and from anterior to posterior longitudinal ligament anteroposteriorly. The **dura** should be visible centrally, and **nerve roots** visible laterally. **Foraminotomy** (if foraminal stenosis present): Use Kerrison rongeurs to remove uncovertebral joint and open foramen for nerve root decompression. ### Step 10: Trial and Insert Interbody Cage **Prepare endplates:** Ensure parallel surfaces with adequate bone surface for fusion. Remove residual cartilage. **Trial sizing:** Use trials to determine appropriate cage height. The goal is to **restore disc height** (visible on lateral fluoroscopy) without over-distraction (causes graft subsidence and dysphagia). **Pack graft material:** Use **autograft** (local bone from vertebral body), **allograft** (cancellous chips), or **bone graft substitute** (ceramic, BMP) to pack the cage. **Insert cage:** Tap or press cage into disc space under fluoroscopic guidance. Cage should sit **flush or 1-2mm proud** of anterior vertebral body. **Confirm position:** Lateral and AP fluoroscopy to ensure cage centered in disc space and appropriate height. ### Step 11: Apply Anterior Plate (If Used) **Modern technique** uses **zero-profile devices** (cage with integrated fixation) in many cases to reduce dysphagia from plate prominence. However, **traditional plating** is still common, especially for multilevel or revision cases. **Plate placement:** 1. **Select plate length** to span the fusion (measured from fluoroscopy) 2. **Bend plate** to match cervical lordosis (pre-contoured or manually bend) 3. **Position plate** centered on midline, flush with anterior vertebral body (not proud) 4. **Drill pilot holes** under fluoroscopy (unicortical, 14-15mm depth typically) 5. **Measure screw length** with depth gauge (subtract 2mm for safety margin) 6. **Insert screws** (variable angle screws allow 15° angulation for optimal purchase) 7. **Confirm position** with AP and lateral fluoroscopy **Screw trajectory:** Aim **toward midline and cephalad** (not straight anterior-posterior, which risks posterior cortex violation and cord injury). The screws should be **unicortical** (do not engage posterior cortex). {/* SECTION 8: CLOSURE */} ### Remove Retractors and Inspect Field **Remove self-retaining retractors** and **Caspar pins**. **Irrigate copiously** with normal saline (500-1000cc) to remove bone debris and reduce infection risk. **Achieve meticulous hemostasis:** Use electrocautery or bipolar for any bleeding vessels. Check the longus colli muscle bellies for bleeding. **Bone wax** for vertebral body bleeding if needed. **Inspect the esophagus:** Ensure no injury occurred during retraction. The esophagus should appear normal without perforation or hematoma. If there is ANY concern for esophageal injury (tear, discoloration), obtain **immediate general surgery or ENT consult** for direct visualization (esophagoscopy) before closing. ### Drain Placement (Controversial) **Closed suction drain** (e.g., 7mm flat Blake drain) is placed by some surgeons to prevent hematoma. Others avoid drains (no proven benefit, may increase infection risk). **Indications for drain:** 1. **Multilevel surgery** (more dead space) 2. **Revision surgery** (more bleeding) 3. **Significant bleeding** despite hemostasis 4. **Anticoagulation** planned postoperatively **Drain positioning:** Superficial to prevertebral fascia (NOT deep to fascia where it could compress esophagus or trachea). Exit through separate stab incision. Remove at 24 hours or when output less than 30cc/8 hours. ### Layer-by-Layer Closure **1. Prevertebral fascia:** **Re-approximate the prevertebral fascia** over the anterior spine using **3-0 Vicryl** interrupted or running suture. This provides an additional layer over the hardware. **2. Platysma muscle:** **Close platysma** using **3-0 Vicryl** interrupted sutures. This layer provides strength to the closure and reduces dead space. **3. Subcutaneous layer:** **Close subcutaneous tissue** using **3-0 Vicryl** interrupted or running suture to obliterate dead space. **4. Skin:** **Skin closure options:** - **Subcuticular 4-0 Monocryl** (absorbable, good cosmesis, patient preference) - **Skin staples** (faster, easier removal, slightly worse cosmesis) - **Skin glue** (Dermabond) over subcuticular suture (best cosmesis, no removal needed) **Apply sterile dressing:** Adaptic or Xeroform, gauze, Tegaderm. Some surgeons avoid bulky dressings (cause patient anxiety about "what's under there"). {/* SECTION 9: POSTOPERATIVE MANAGEMENT */} ### Immediate Postoperative Care (First 24 Hours) **Airway monitoring:** The **most critical complication** in the immediate postoperative period is **airway compromise** from hematoma or edema. Patients are monitored in recovery or ICU for **4-6 hours minimum** (some centers admit overnight for multilevel cases). **Warning signs of airway compromise:** 1. **Neck swelling** (expanding hematoma) 2. **Dyspnea** (difficulty breathing) 3. **Stridor** (inspiratory noise from airway narrowing) 4. **Dysphagia** (difficulty swallowing, drooling) 5. **Change in voice** (hoarseness) **Management of expanding hematoma:** This is a **surgical emergency**. If airway compromise develops: 1. **Call for anesthesia** (prepare for reintubation) 2. **Open wound at bedside** (remove staples/sutures, evacuate hematoma) 3. **Return to OR** for formal washout and hemostasis once airway secured **Neurological checks:** Check **upper and lower extremity motor and sensory** function every 2 hours for first 24 hours. New deficit suggests cord or root injury (hematoma, graft malposition, screw misplacement) - obtain immediate CT scan. **Drain management:** If drain placed, record output every 4 hours. Remove when output less than 30cc/8 hours (usually 24 hours). High output (greater than 100cc/8 hours) suggests active bleeding - check hemoglobin, consider re-exploration if hemodynamically unstable. ### Pain Management **Multimodal analgesia:** 1. **Acetaminophen** 1000mg PO/IV every 6 hours (baseline) 2. **NSAIDs** (if no contraindication): ketorolac 30mg IV every 6 hours x 48 hours, then ibuprofen 600mg PO TID 3. **Opioids** (for breakthrough pain): oxycodone 5-10mg PO every 4 hours PRN or hydromorphone 0.5-1mg IV every 4 hours PRN 4. **Muscle relaxants** (if muscle spasm): diazepam 5mg PO TID or cyclobenzaprine 10mg PO TID **Most patients** have minimal neck pain (the approach is atraumatic to muscles). **Arm pain** (preoperative radiculopathy) often improves immediately but can take weeks to fully resolve as nerve inflammation settles. ### Dysphagia Management **Dysphagia** (difficulty swallowing) occurs in **30-50% of patients** in the immediate postoperative period, improving to **10-15% at 6 weeks** and **5% at 1 year**. **Causes:** 1. **Soft tissue edema** from retraction (most common, resolves in days-weeks) 2. **Esophageal injury** (rare but serious) 3. **RLN injury** (causes aspiration more than dysphagia) 4. **Hardware prominence** (plate sitting proud, zero-profile cages reduce this) **Initial management:** Start with **clear liquids** on postoperative day 0 if no airway concerns. Advance to **soft diet** (pureed foods, yogurt, pudding) on POD 1. **Regular diet** by POD 2-3 as tolerated. **Persistent dysphagia** (beyond 6 weeks): Consider **speech pathology consult** for swallowing evaluation, **barium swallow study** to assess swallow mechanics, and **revision surgery** if hardware prominence is the cause. ### Cervical Collar **Use of cervical collar is CONTROVERSIAL** and varies widely: **No collar** (modern approach): Many surgeons now avoid collar entirely for single-level ACDF with rigid plate fixation. Early mobilization improves patient satisfaction and return to function. **Comfort collar only** (soft collar 1-2 weeks): Patients wear collar for comfort during sleep or car rides but remove for daily activities. This is the most common current practice. **Hard collar 6-12 weeks** (traditional approach): Some surgeons still use Miami J or Aspen collar for 6 weeks until fusion evidence on X-ray, especially for multilevel cases or patients with poor bone quality. **Evidence:** Multiple studies show **no difference in fusion rates** between collar and no-collar groups for single-level ACDF with plate. The collar does NOT improve fusion but may reduce patient anxiety. ### Activity Restrictions **General guidelines:** 1. **Walking:** Encouraged immediately (day of surgery). Walking improves circulation and reduces DVT risk. 2. **Driving:** Resume when off opioid medications and can turn head comfortably (2-4 weeks typically) 3. **Return to work:** - **Sedentary work** (computer, desk): 2-4 weeks - **Light manual labor**: 6-12 weeks - **Heavy manual labor**: 3-6 months (wait for fusion evidence) 4. **Lifting restrictions:** No lifting greater than 5kg for 6 weeks, then gradual progression 5. **Sports:** Non-contact sports at 3 months, contact sports at 6 months (with fusion evidence) ### Radiographic Follow-Up **Standard protocol:** 1. **Immediate postoperative** (day 0 or 1): AP and lateral C-spine X-rays to document hardware position, alignment, disc height 2. **6 weeks:** AP and lateral X-rays to assess early healing, hardware position (check for subsidence or screw pullout) 3. **3 months:** AP, lateral, and **flexion-extension lateral** X-rays to assess fusion (bridging bone across disc space, less than 2mm motion on flexion-extension) 4. **6 months and 1 year:** Repeat films if fusion uncertain or patient symptomatic **Fusion criteria** (visible on X-ray): 1. **Bridging bone** across disc space (visible trabeculation through cage) 2. **No lucency** around cage or screws (lucency suggests non-union) 3. **Less than 2mm motion** on flexion-extension views 4. **No hardware failure** (screw breakage, plate fracture) **CT scan** if fusion uncertain on X-ray (better visualization of bone bridging, especially with metal artifact reduction sequences). ### Smoking Cessation Enforcement **Smoking increases pseudarthrosis risk from 5% to 20-30%.** Surgeons should: 1. **Document smoking status** preoperatively 2. **Counsel on cessation** (Quitline 13 7848 referral) 3. **Consider nicotine testing** before elective surgery 4. **Reinforce cessation postoperatively** (fusion occurs over 3-6 months, smoking impairs this process) Some studies suggest **financial incentives** for smoking cessation improve quit rates in surgical patients. {/* SECTION 10: COMPLICATIONS */} ### Early Complications (Less Than 6 Weeks) **1. Recurrent Laryngeal Nerve (RLN) Palsy (2-5% transient, 0.2% permanent):** **Presentation:** Hoarseness, weak voice, difficulty with high-pitched sounds (cannot sing or shout). **Bilateral RLN palsy** (rare) causes airway obstruction from both vocal cords in paramedian position - requires emergency tracheostomy. **Diagnosis:** **Laryngoscopy** by ENT shows vocal cord paralysis (cord in paramedian or lateral position, not moving with phonation). **Management:** - **Observation** for unilateral palsy (most resolve in 6-12 months as neuropraxia recovers) - **Speech therapy** to teach compensatory techniques (increased airflow, pitch modification) - **Medialization thyroplasty** (injection of implant into paralyzed vocal cord to push it toward midline, allowing better closure during phonation) if no recovery by 6-12 months - **Tracheostomy** for bilateral palsy (emergency airway) **Prevention:** See SafetyAlert above (gentle retraction, release pressure every 30 minutes, avoid electrocautery in tracheoesophageal groove). **2. Superior Laryngeal Nerve (External Branch) Injury (1-2%):** **Presentation:** Difficulty with high-pitched voice, cannot sing in high register, voice fatigues quickly. This is distinct from RLN injury (which causes hoarseness and weak voice). **Mechanism:** Injury to external branch of superior laryngeal nerve (innervates cricothyroid muscle) during dissection at C3-4 level (high cervical approach). **Management:** Observation (most improve over 6-12 months), speech therapy. No surgical treatment. **3. Dysphagia (30-50% early, 5% at 1 year):** **Presentation:** Difficulty swallowing solids or liquids, feeling of lump in throat, need to drink water with meals. **Causes:** Soft tissue edema (most common, resolves), esophageal injury (rare but serious), plate prominence (zero-profile cages reduce this), multilevel surgery (higher risk). **Management:** - **Dietary modification:** Soft diet, small bites, adequate hydration - **Speech pathology consult** for swallowing evaluation if persistent - **Barium swallow study** if concern for esophageal injury or severe dysphagia - **Revision surgery** to remove prominent hardware if symptomatic at 6+ months **4. Hematoma (1-2%):** **Presentation:** Neck swelling, dyspnea, stridor (airway compromise), dysphagia. Can occur immediately or delayed (up to 24 hours). **Management:** This is a **surgical emergency** if airway compromise: 1. **Open wound at bedside** (remove sutures, evacuate hematoma) to relieve pressure 2. **Prepare for reintubation** (anesthesia at bedside) 3. **Return to OR** for formal washout and hemostasis once airway secured **Prevention:** Meticulous hemostasis before closure, consider drain for multilevel or revision cases, monitor in recovery/ICU for 4-6 hours minimum. **5. C5 Nerve Root Palsy (1-2% with ACDF, higher with corpectomy):** **Presentation:** Deltoid and biceps weakness (shoulder abduction and elbow flexion weak) developing within 24-48 hours postoperatively. Sensory loss over lateral shoulder (axillary nerve distribution). **Mechanism:** Uncertain. Theories include: cord shift after decompression (tethering C5 root), direct root injury from foraminotomy, reperfusion injury. **Management:** Observation (most recover over 6-12 months), physical therapy for range of motion and strengthening. **Prevention:** Avoid aggressive foraminotomy at C4-5 level, gentle distraction during discectomy. **6. Dural Tear (1-2%):** **Presentation:** CSF leak from dura during discectomy or PLL resection. Clear fluid pooling in wound. **Management:** - **Primary repair** with 6-0 Prolene if tear is accessible (small tears can be difficult to repair from anterior) - **Fibrin glue or DuraSeal** over tear if suture repair not possible - **Flat bed rest** for 24-48 hours postoperatively - **Lumbar drain** if persistent CSF leak (rare) **Prognosis:** Most heal without intervention. Risk of meningitis if persistent leak or communication with pharynx. ### Late Complications (Greater Than 6 Weeks) **1. Pseudarthrosis (Non-Union) (5% single-level, 10-20% multilevel):** **Definition:** Failure of fusion at 6-12 months (no bridging bone, motion on flexion-extension X-rays). **Risk factors:** Smoking (strongest predictor), multilevel fusion, poor bone quality, inadequate endplate preparation, NSAID use. **Presentation:** May be asymptomatic (incidental finding on X-ray) or symptomatic (neck pain, recurrent radiculopathy, hardware failure). **Management:** - **Observation** if asymptomatic (some pseudarthroses are stable and cause no symptoms) - **Revision surgery** (anterior revision with new graft and plate, or posterior fusion) if symptomatic **Prevention:** Smoking cessation, adequate endplate preparation (remove cartilage to bleeding bone), appropriate graft choice (autograft superior to allograft for fusion), avoid NSAIDs in first 3 months, consider BMP for high-risk patients. **2. Adjacent Segment Disease (ASD) (10-25% at 10 years):** **Definition:** Degenerative changes (disc herniation, stenosis, instability) at levels adjacent to fusion requiring surgery. **Controversy:** Unclear whether fusion **causes** ASD (via altered biomechanics and stress transfer) or ASD is **natural history** of cervical spondylosis in patients predisposed to degeneration. **Management:** Observation if asymptomatic. Surgery (ACDF at new level or motion-preserving arthroplasty) if symptomatic. **Prevention:** Restore normal disc height and lordosis (reduces stress on adjacent levels), consider cervical arthroplasty (motion-preserving) in young patients (controversial - long-term data pending). **3. Hardware Failure (1-3%):** **Presentation:** Screw pullout, screw breakage, plate fracture. Usually occurs in setting of pseudarthrosis (motion causes hardware fatigue). **Management:** Revision surgery if symptomatic (persistent pain, neurological deficit) or progressive deformity. **4. Subsidence (Graft or Cage Sinking into Endplate) (5-10%):** **Presentation:** Loss of disc height on postoperative X-rays (visible within weeks to months). Can cause recurrent foraminal stenosis (collapse of disc space narrows foramen). **Risk factors:** Over-distraction during surgery (cage too tall), poor bone quality (osteoporosis), inadequate endplate preparation. **Management:** Observation if asymptomatic. Revision if symptomatic radiculopathy (foraminotomy or revision fusion with larger graft). **Prevention:** Appropriate cage sizing (restore native disc height, avoid over-distraction), preserve endplate integrity (do not violate subchondral bone excessively). **5. Horner Syndrome (Less Than 1%):** **Presentation:** Miosis (pupil constriction), ptosis (eyelid droop), anhidrosis (loss of facial sweating) on operative side. **Mechanism:** Sympathetic chain injury (chain runs on longus colli muscle - injured by excessive lateral dissection or retraction). **Management:** Observation (most resolve in 3-6 months, some permanent). No specific treatment. {/* SECTION 11: EVIDENCE-BASED PRACTICE */} {/* SECTION 12: VIVA SCENARIOS */} {/* SECTION 13: MNEMONICS */} {/* SECTION 14: EXAM CHEAT SHEET */}

Smith-Robinson Approach (Anterior Cervical Spine)

Smith-Robinson Approach (Anterior Cervical Spine)