KASHIMA'S CORDOTOMY (POSTERIOR LASER CORDOTOMY)

A Comprehensive 50-Mark Answer | RGUHS University Standard

1. INTRODUCTION AND HISTORICAL BACKGROUND

• 1922 - Chevalier Jackson: Open ventriculocordectomy (first surgical attempt)
• 1948 - Thornell: Endoscopic arytenoidectomy
• 1976 - Strong et al.: First CO2 laser endoscopic arytenoidectomy
• 1989 - Dennis DP and Kashima HK: Introduced CO2 laser posterior cordotomy (Ann Otol Rhinol Laryngol, 1989)
• 1991 - Kashima HK: Further described bilateral vocal fold motion impairment and management (Ann Otol Rhinol Laryngol, 1991)
• 1999 - Laccourreye et al.: CO2 laser endoscopic posterior partial transverse cordotomy

• Cummings Otolaryngology Head and Neck Surgery (Reference #108, block46)
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Vol 2
• K.J. Lee's Essential Otolaryngology

2. ANATOMY RELEVANT TO KASHIMA'S CORDOTOMY

Laryngeal Anatomy at the Operative Site

CORONAL VIEW OF POSTERIOR GLOTTIS
═══════════════════════════════════════

         ANTERIOR
            |
  ┌─────────┴─────────┐
  │   THYROID         │
  │   CARTILAGE       │
  │                   │
  │  ◄── Vocal fold──►│
  │    (paramedian    │
  │     position)     │
  │                   │
  │  [CONUS ELASTICUS]│ ← KEY STRUCTURE CUT
  │                   │
  │   CRICOID         │
  │   CARTILAGE       │
  └───────────────────┘
         |
       POSTERIOR
       
Key Structures:
• Vocal process of arytenoid
• Membranous vocal cord (anterior 2/3)
• Cartilaginous cord (posterior 1/3 - vocal process)
• Conus elasticus (elastic cone)
• Thyroarytenoid (TA) muscle
• Posterior glottic chink (3-4 mm in BVFP)

Normal vs. Bilateral Vocal Fold Paralysis Position

AXIAL VIEW (Top Down)

NORMAL POSITION         BILATERAL ABDUCTOR PALSY
                        (Paramedian/Median position)
      A                         A
      |                         |
  ══╗ | ╔══              ══╗  | ╔══
  VC╝ | ╚VC              VC╝▐█▌╚VC
      |                      ↑
   Glottis OPEN          Narrow chink
   (8-10mm)              (2-3mm)
   
VC = Vocal Cord   A = Anterior Commissure

• Severe dyspnea and stridor (inspiratory + expiratory)
• Adequate voice (cords in near-adducted position)
• Risk of acute respiratory failure

3. ETIOLOGY OF BILATERAL VOCAL FOLD PARALYSIS

4. SURGICAL OPTIONS FOR BILATERAL VOCAL CORD PARALYSIS

FLOWCHART 1: MANAGEMENT OF BILATERAL VOCAL CORD PALSY
════════════════════════════════════════════════════════

Bilateral Vocal Cord Paralysis (BVFP) Diagnosed
                    │
          ┌─────────┴──────────┐
     ACUTE Airway             STABLE Airway
     Compromise               (Stridor on exertion)
          │                          │
    EMERGENCY              WAIT & WATCH (3-6 months)
    TRACHEOSTOMY           for spontaneous recovery
          │                          │
          │               No recovery at 6 months
          │                          │
          └──────────┬───────────────┘
                     ▼
           SURGICAL INTERVENTION
                     │
        ┌────────────┼───────────────┐
        │            │               │
  EXTERNAL        ENDOSCOPIC      NEWER
  PROCEDURES      PROCEDURES      PROCEDURES
        │            │               │
  - Woodman's    - Laser          - Reinnervation
    Arytenoidec.   Arytenoidectomy  (RLN anastomosis)
  - Laterofixation - Kashima's    - Laryngeal pacing
                   Cordotomy      - Botulinum toxin
                   - Endoscopic   - Suture laterali-
                     Arytenoidopexy  zation

Classification of Surgical Procedures

5. KASHIMA'S CORDOTOMY - DEFINITION

• "Cordotomy can be performed endoscopically by resecting part of the posterior true vocal fold unilaterally and dividing the conus elasticus, usually with a CO2 laser."
  • Cummings Otolaryngology Head and Neck Surgery, Block 46, p.3949

6. INDICATIONS

• Bilateral vocal cord paralysis (abductor palsy) - both cords in paramedian/median position causing respiratory distress

1. Bilateral RLN palsy with respiratory distress
2. Failed conservative management (>6 months of watchful waiting)
3. Tracheostomy-dependent patients requiring decannulation
4. Stridor significant enough to limit daily activities or sleep
5. Bilateral vocal cord paralysis in children (adapted technique)
6. Cases where voice quality must be maximally preserved (vs. total arytenoidectomy)
7. Patients at high anesthetic risk for longer procedures (office-based laser option)

1. Active laryngeal malignancy
2. Poor coagulation status
3. Glottic stenosis with interarytenoid scarring (posterior glottic stenosis - requires different approach)
4. Posterior glottic stenosis mimicking bilateral cord palsy
5. Bilateral cricoarytenoid joint fixation

7. PRE-OPERATIVE ASSESSMENT

FLOWCHART 2: PRE-OPERATIVE WORKUP
══════════════════════════════════

Patient with suspected BVFP
          │
    ┌─────┴──────┐
HISTORY           EXAMINATION
- Prior thyroid   - General respiratory
  surgery           assessment
- Neck malignancy - Voice quality
- Intubation hx   - Indirect laryngoscopy
- Duration of     - Flexible nasolaryngo-
  symptoms          scopy
    └─────┬──────┘
          ▼
    INVESTIGATIONS
    ├── Flexible Fibreoptic Laryngoscopy
    │   (Gold standard - confirms bilateral
    │   cord immobility in paramedian position)
    ├── Stroboscopy (vocal fold vibration)
    ├── EMG Laryngeal (distinguish palsy from fixation)
    ├── CT Neck/Chest (rule out compressive lesion)
    ├── Pulmonary function tests (objective airway)
    └── Voice Handicap Index (VHI) - baseline
          │
    DIFFERENTIAL DIAGNOSIS
    ├── Posterior glottic stenosis (scarring)
    ├── Bilateral cricoarytenoid joint fixation
    │   (e.g., RA, gout)
    └── Intubation granuloma

8. INSTRUMENTS REQUIRED

1. Suspension microlaryngoscope (Kleinsasser / Lindholm laryngoscope)
2. Operating microscope
3. CO2 laser (10,600 nm wavelength) - primary energy source
4. Microlaryngeal instruments (forceps, suction)
5. Laser-safe endotracheal tube or jet ventilation setup
6. Laser safety goggles (for all theatre staff)
7. Wet gauze or saline-soaked pledgets (protect surrounding tissues)
8. Suction apparatus

9. ANESTHESIA

• General anesthesia - standard approach
• Options:
  • Jet ventilation (supraglottic / subglottic) - preferred with CO2 laser (avoids laser ignition risk with ETT)
  • Laser-safe armoured ETT (Mallinckrodt Laser Flex / Norton tube) with FiO2 <30%, remainder N2
  • Spontaneous ventilation with deep inhalational anesthesia (in experienced centers)
• Position: Supine with neck slightly extended (Rose position)

10. OPERATIVE TECHNIQUE - STEP-BY-STEP

FLOWCHART 3: STEP-BY-STEP OPERATIVE TECHNIQUE
════════════════════════════════════════════════

STEP 1: PATIENT POSITIONING
Patient supine, neck extended (Rose position)
Teeth guard placed, shoulder roll if needed
           │
           ▼
STEP 2: DIRECT LARYNGOSCOPY
Suspension laryngoscope introduced (Kleinsasser)
Suspended to chest support / Mayo stand
Vocal cords visualized under microscope
CONFIRM: Both cords in paramedian position
           │
           ▼
STEP 3: SELECTION OF CORD
Typically RIGHT vocal cord (surgeon's preference)
If tracheostomized: start unilaterally
           │
           ▼
STEP 4: MARKING THE INCISION SITE
Just ANTERIOR to the VOCAL PROCESS of arytenoid
At the junction of posterior and middle 1/3
of the membranous vocal cord
           │
           ▼
STEP 5: CO2 LASER CORDOTOMY
CO2 laser (focused mode, 2-5W continuous or
superpulse) used to make TRANSVERSE incision
through the full thickness of the vocal cord
           │
           ▼
STEP 6: LATERAL EXTENSION
Incision extended LATERALLY (2-3 mm) into
paraglottic space to release tension
The CONUS ELASTICUS is divided
Tissue resection advances laterally until
inner perichondrium of thyroid/cricoid cartilage
           │
           ▼
STEP 7: C-SHAPED WEDGE EXCISION
A C-shaped wedge of posterior vocal fold tissue
is excised from the free border
(This is the KEY DIFFERENTIATING STEP)
           │
           ▼
STEP 8: HEMOSTASIS
CO2 laser provides excellent hemostasis
Any residual bleeding managed with laser/suction
           │
           ▼
STEP 9: ASSESSMENT OF AIRWAY
Posterior glottic chink now 5-6 mm (from 2-3 mm)
Confirm adequacy of glottic opening
           │
           ▼
STEP 10: DECISION - BILATERAL OR UNILATERAL?
If unilateral adequate → STOP
If insufficient airway → proceed to
CONTRALATERAL CORD (same session or staged)

Diagrammatic Representation of the Cordotomy

OPERATIVE DIAGRAM - VOCAL CORD (Axial View from above)

BEFORE KASHIMA'S CORDOTOMY:
      Anterior commissure
            /\
           /  \
    Left  /    \ Right
    cord /      \ cord
        |  ████  |
        | NARROW |
        |  CHINK |
         \      /
          \    /
     Arytenoids

████ = Near-closed glottis (2-3mm chink)


AFTER UNILATERAL KASHIMA'S CORDOTOMY (Right Side):

      Anterior commissure
            /\
           /  \
    Left  /    \  Right cord
    cord /      \  (POSTERIOR
        |     ╔══╝  PORTION
        |     ║     EXCISED)
        |     ╚══►  C-shaped
        |     wedge removed
        |  ENLARGED   |
        |  CHINK      |
         \           /
          Arytenoids

Result: 5-7 mm posterior glottic opening
Voice: Preserved (anterior cord intact)

CROSS-SECTION OF VOCAL CORD SHOWING PLANES OF DISSECTION

     MUCOSAL SURFACE (Superior)
     ┌────────────────────────┐
     │    Epithelium          │
     │    Lamina propria      │ ← Reinke's space
     │    Vocal ligament      │ ← Divided here
     │    TA muscle           │ ← Partially removed
     └────────────────────────┘
           POSTERIOR PORTION

     ▼ Kashima cuts THROUGH ALL LAYERS at posterior cord
     ▼ Extends LATERALLY to inner perichondrium
     ▼ CONUS ELASTICUS is divided (key step)

11. SPECIFIC TECHNICAL STEPS (Expanded - as per Cummings & Stell and Maran)

1. Patient position: Rose position (supine, neck extended, shoulder roll)
2. Laryngoscopy: Direct suspension microlaryngoscopy
3. Anesthesia: Jet ventilation preferred (avoids ETT laser fire risk); if ETT used, laser-safe tube with FiO2 <30%
4. Cord selection: Usually right cord first; unilateral initially
5. Incision site: Transverse incision placed immediately anterior to the vocal process of the arytenoid
6. Depth: Full-thickness incision through mucosa, Reinke's space, vocal ligament, and thyroarytenoid muscle down to conus elasticus
7. Lateral extension: 2-3 mm lateral extension into the paraglottic space, releasing the conus elasticus
8. Tissue removal: A C-shaped or wedge-shaped piece of posterior vocal cord tissue is excised using CO2 laser
9. The preserved area: Anterior 2/3 of vocal cord is NOT disturbed - this preserves phonation
10. End result: Posterior glottic airway widened from ~3mm to ~6-7mm

12. COMPARISON WITH OTHER PROCEDURES

COMPARISON TABLE: GLOTTIC WIDENING PROCEDURES

Parameter      | Kashima's    | Total         | Woodman's    | Suture
               | Cordotomy    | Arytenoidec.  | Proc.        | Laterali-
               |              |               |              | zation
───────────────┼──────────────┼───────────────┼──────────────┼──────────
Approach       | Endoscopic   | Endoscopic    | External     | Endoscopic
Reversible?    | No           | No            | No           | Yes
Voice outcome  | Good (ant.   | Fair-poor     | Poor         | Best
               | cord spared) |               |              |
Airway         | Good         | Excellent     | Excellent    | Good
Improvement    |              |               |              |
Aspiration     | Low          | High          | Moderate     | Low
risk           |              |               |              |
Decannulation  | 95.1%        | 83%           | >90%         | Variable
rate           | (cordotomy)  | (arytenoid.)  |              |
Granuloma      | 30%          | Less common   | Less common  | 5-10%
formation      |              |               |              |
Repeatability  | Yes (easy)   | Difficult     | No           | Yes
Operating time | Short        | Moderate      | Long         | Short

13. POST-OPERATIVE CARE

1. Airway monitoring: ICU/HDU for 24-48 hours, watch for post-operative edema
2. Voice rest: 7-10 days of voice rest recommended
3. Oral feeds: Can resume within 24-48 hours (soft diet initially; monitor for aspiration)
4. Steroids: Systemic dexamethasone 0.1mg/kg for 48 hours to reduce edema
5. Antibiotics: Short course (co-amoxiclav) if mucosal breach is extensive
6. Inhaled steroids: Post-op inhaled budesonide reduces granulation tissue formation (Hollis et al., Ann Otol Rhinol Laryngol, 2022 [PMID: 34965742])
7. Tracheostomy care: If already tracheostomized, capping trials begin at 2 weeks post-op
8. Decannulation criteria: Adequate oxygen saturation with capped tracheostomy, stable glottic aperture on laryngoscopy, no dysphagia
9. Follow-up laryngoscopy: At 4 weeks, 3 months, and 6 months post-op

14. COMPLICATIONS

FLOWCHART 4: COMPLICATIONS AND THEIR MANAGEMENT
═════════════════════════════════════════════════

COMPLICATIONS
      │
      ├── INTRA-OPERATIVE
      │   ├── Airway fire (ETT + CO2 laser + O2) → Jet ventilation prevents this
      │   ├── Bleeding → Usually controlled by laser
      │   └── Inadequate exposure → Reposition laryngoscope
      │
      ├── EARLY POST-OPERATIVE
      │   ├── Edema / Stridor → Steroids, re-scope, consider reintubation
      │   ├── Aspiration → Swallowing rehabilitation
      │   └── Infection → Antibiotics
      │
      └── LATE POST-OPERATIVE
          ├── GRANULOMA FORMATION (30%) ← Most common complication
          │   Cause: Bare cartilage exposed at cordotomy site
          │   Management: Re-laser, inhaled steroids (PMID: 34965742)
          │
          ├── RESTENOSIS/SCAR FORMATION (30%)
          │   Cause: Wound healing closes posterior glottis
          │   Management: Revision cordotomy (easily repeatable)
          │
          ├── VOICE DETERIORATION
          │   Cause: Scar at posterior cord, altered vibration
          │   Management: Voice therapy; accept trade-off
          │
          └── FAILURE TO DECANNULATE
              Management: Bilateral cordotomy or partial arytenoidectomy

• Granuloma/restenosis requiring revision: ~30% of cases
• Decannulation rate: 95.1% (unilateral + bilateral transverse cordotomy combined) (Lechien et al., literature review)
• Aspiration: Low risk compared to arytenoidectomy
• Dysphagia: Present in some patients (Conklin et al., Ann Otol Rhinol Laryngol, 2020 [PMID: 31888349])

15. RESULTS AND OUTCOMES

16. UNILATERAL vs. BILATERAL CORDOTOMY

ALGORITHM: UNILATERAL vs. BILATERAL APPROACH
══════════════════════════════════════════════

STEP 1: Perform UNILATERAL posterior cordotomy
(Right cord preferred)
              │
        ┌─────┴──────┐
   Adequate         Inadequate
   airway           airway (still
   obtained         symptomatic)
        │                │
   STOP here        STAGE 2: Perform
   Monitor          CONTRALATERAL
   Follow-up        cordotomy
                    (same or next session)
                         │
                  Voice more affected
                  with bilateral

17. RECENT ADVANCES (2015-2026)

A. New Energy Sources for Cordotomy

• Elnaggar et al. (J Voice, 2024 [PMID: 39043533]) compared RF vs. CO2 laser
• Both effective; CO2 laser superior for breathing improvement and exercise tolerance
• RF has advantage of no laser fire risk

• Ozturk et al. (Clin Otolaryngol, 2018 [PMID: 28800194]): Diathermy comparable to CO2 laser
• Cheaper, more widely available

• Hamdan et al. (J Voice, 2026 [PMID: 39492033]): Office-based blue laser posterior cordectomy
• Performed under topical anesthesia in office - avoids general anesthesia
• Suitable for high anaesthetic risk patients
• Results: Improved glottal gap, no voice worsening in both cases

• Lin et al. (Clin Otolaryngol, 2023 [PMID: 37052314]): CO2 laser-modified posterior cordotomy + coblation subtotal arytenoidectomy
• 100% decannulation in 22 patients; no worsening of voice or swallowing
• Posterior glottis >3.9 mm in all patients

B. Combined Procedures

• Abdelhamid et al. RCT (Am J Otolaryngol, 2022 [PMID: 34954585]): 40 patients randomized
• Combined group showed less granuloma formation and better maximum phonation time
• Comparable respiratory outcomes

C. Modified Surgical Approaches

• A 2D-enlargement technique: Vocal cord flap sutured laterally
• Better voice outcome (80%) vs. Kashima's (posterior tissue lost)
• Uses 5-0 Vicryl Rapide (absorbable) to prevent granulation

• Emerging role for cordotomy in difficult laryngeal exposure cases

• RLN anastomosis (phrenic nerve as source)
• Muscle-nerve pedicle transplant to PCA muscle (omohyoid/sternohyoid)
• Functional Electrical Stimulation (FES) of paralyzed PCA
• Still investigational; promising for young patients

D. Office-Based Procedures

• Flexible laryngoscopy-guided laser procedures under topical anesthesia
• Avoids GA risk in frail/elderly patients

E. Post-operative Inhaled Steroids

• Hollis et al. (Ann Otol Rhinol Laryngol, 2022 [PMID: 34965742]): Inhaled steroids after glottic surgery reduces granulation tissue formation - a major advance in reducing revision rate

18. COMPARISON OF SURGICAL PROCEDURES (Comprehensive Table as per RGUHS)

19. MNEMONICS FOR RGUHS EXAM

• Positioning (Rose position)
• Laryngoscopy (suspension microlaryngoscopy)
• Anesthesia (jet ventilation)
• Cord selection (right, unilateral first)
• Excision site (anterior to vocal process)
• Cut transversely (CO2 laser, full thickness)
• Hemostasis (laser coagulation)
• Assess airway (5-7mm posterior chink)

• Granuloma (most common, 30%)
• Restenosis/Scar
• Aspiration
• Voice deterioration
• Edema (early)

20. EXAM SUMMARY TABLE (RGUHS 50-Mark Standard)

REFERENCES

1. Dennis DP, Kashima H. Carbon dioxide laser posterior cordectomy for treatment of bilateral vocal cord paralysis. Ann Otol Rhinol Laryngol. 1989;98(12):930-934.
2. Kashima HK. Bilateral vocal fold motion impairment: pathophysiology and management by transverse cordotomy. Ann Otol Rhinol Laryngol. 1991;100(9):717-721. - (Cited in Cummings Otolaryngology, Reference #108)
3. Cummings Otolaryngology Head and Neck Surgery (7th Ed.) - Bilateral True Vocal Fold Immobility, p.3949
4. Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Vol 2 - Posterior glottic stenosis section; bilateral vocal cord paralysis management
5. K.J. Lee's Essential Otolaryngology - Vocal Cord Dysfunction section, p.8137-8154
6. Schwartz's Principles of Surgery (11th Ed.) - Benign Conditions of the Larynx
7. Maqbool T, Ahmed R, Ali I. Our Experience with Kashima's Procedure for Bilateral Abductor Vocal Cord Palsy. Iran J Otorhinolaryngol. 2020 Sep. [PMID: 33014904]
8. Abdelhamid MA et al. A comparative study of laser posterior cordotomy and combined laser posterior cordotomy with suture lateralization. Am J Otolaryngol. 2022. [PMID: 34954585] - RCT, Evidence Level 1b
9. Elnaggar A et al. Radiofrequency versus CO2 laser in posterior cordotomy for managing bilateral abductor vocal fold immobility. J Voice. 2024. [PMID: 39043533]
10. Hamdan AL et al. Office-based blue laser posterior cordectomy in patients with bilateral vocal fold paralysis. J Voice. 2026. [PMID: 39492033]
11. Lin Q et al. Transoral CO2 laser-modified posterior cordotomy combined with plasma ablation subtotal arytenoidectomy for bilateral vocal fold paralysis. Clin Otolaryngol. 2023. [PMID: 37052314]
12. Hollis AN et al. Postoperative inhaled steroids following glottic airway surgery reduces granulation tissue formation. Ann Otol Rhinol Laryngol. 2022. [PMID: 34965742]
13. Laccourreye O et al. CO2 laser endoscopic posterior partial transverse cordotomy for bilateral paralysis of the vocal fold. Laryngoscope. 1999;109(3):415-418.
14. Dhingra PL, Dhingra S. Diseases of Ear Nose and Throat (7th Ed.) - Bilateral Vocal Cord Paralysis.
15. Hazarika P. Ear Nose Throat: Head and Neck Surgery - Bilateral Vocal Cord Palsy management.
16. Stell & Maran's Head and Neck Surgery - Laryngeal paralysis and cordotomy.

RGUHS Exam Tip: In a 50-mark question, allocate marks as follows: Introduction + History (5), Anatomy (5), Etiology/Indications (5), Pre-op workup (5), Operative technique with diagrams (15), Post-op care (5), Complications (5), Comparison with other procedures (5), Recent advances (5) = 50 marks. The key discriminating points examiners look for are: the exact site of incision (just anterior to vocal process), the importance of conus elasticus division, the C-shaped wedge excision, CO2 laser as energy source, and recent advances including office-based blue laser and RF cordotomy.