import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Branches 5cm proximal to wrist crease, passes between FCR and palmaris longus tendons, runs superficial to flexor retinaculum to innervate thenar skin **Protection**: Start incision AT wrist crease (never proximal), stay in ring finger axis keeping 5mm ulnar to thenar crease, avoid proximal extension beyond distal wrist crease **Location**: Branches from radial side of median nerve 1cm distal to TCL distal edge; three variants - extraligamentous 50%, subligamentous 31%, transligamentous 23% (pierces through TCL) **Protection**: Always divide TCL on ULNAR side maintaining 3-5mm distance from radial edge, inspect for transligamentous variant before division, avoid cautery near radial TCL edge **Location**: Crosses palm 2-3cm distal to TCL distal edge at Kaplan's cardinal line (apex thumb-index web to hook of hamate), formed by ulnar artery with variable median artery contribution **Protection**: Mark Kaplan's line preoperatively, limit distal dissection to fat pad visualization, never extend incision or dissection beyond Kaplan's line, control bleeding with bipolar cautery **Location**: Lies immediately deep (0mm) to TCL, may show hourglass constriction at compression site, can be adherent to ligament undersurface in chronic severe or revision cases **Protection**: Use grooved director under TCL during division, start division at distal edge with direct visualization, avoid blind cuts, maintain protection throughout proximal progression **Location**: Branch from median nerve 1-2cm distal to TCL distal edge, pass distally toward thumb, index, long fingers and radial ring finger, lie deep to superficial arch **Protection**: Limit distal dissection to fat pad only, visualize digital nerves branching to confirm adequate release, avoid aggressive distal exploration beyond Kaplan's line ## Surgical Indications ### Absolute Indications - **Thenar atrophy** with electrodiagnostic confirmation of severe CTS - **Constant numbness** in median nerve distribution unresponsive to splinting - **Acute carpal tunnel syndrome** from trauma, bleeding, burns requiring urgent decompression ### Relative Indications - Failed conservative management after 3-6 months (splinting, activity modification, steroid injection) - Moderate-severe CTS on nerve conduction studies (distal motor latency greater than 4.5ms, sensory latency greater than 3.5ms) - Patient preference for definitive treatment over continued conservative measures - Recurrent symptoms after initial conservative success ### Contraindications **Absolute**: - Active infection in surgical field - Severe medical comorbidities precluding safe anesthesia - Patient unable to comply with postoperative care **Relative**: - Mild CTS responsive to conservative treatment - Pregnancy (usually defer until postpartum unless severe) - Severe CRPS or sympathetic dystrophy in affected limb - Workers' compensation with pending litigation (relative) ## Classification Systems ### Thenar Motor Branch Variants (Lanz Classification) 1. **Group 0 (Extraligamentous)**: 50% - branch arises distal to TCL, courses around radial edge 2. **Group 1 (Subligamentous)**: 31% - branch arises under TCL, exits at distal edge 3. **Group 2 (Transligamentous)**: 23% - branch pierces through TCL substance 4. **Group 3 (Supraligamentous)**: Less than 1% - branch runs superficial to TCL ### Severity Classification (Surgical Perspective) **Mild CTS**: Normal examination, positive Phalen's/Tinel's, intermittent night symptoms - usually managed conservatively **Moderate CTS**: Abnormal sensation, no thenar weakness, positive electrodiagnostics - surgical candidate after failed conservative treatment **Severe CTS**: Thenar atrophy, constant numbness, severe electrodiagnostic abnormalities - absolute surgical indication ## Carpal Tunnel Boundaries ### Osseous/Ligamentous Anatomy **Floor (Dorsal)**: - Distal radius articular surface - Scaphoid and lunate (proximal row) - Trapezium, trapezoid, capitate (distal row) **Roof (Volar)**: - Transverse carpal ligament (flexor retinaculum) - Thick fibrous band 2-3cm long, 2-3mm thick - Attachments: scaphoid tubercle and trapezium (radial), pisiform and hook of hamate (ulnar) **Radial Wall**: Scaphoid tubercle, trapezial ridge **Ulnar Wall**: Pisiform, hook of hamate ## Contents of Carpal Tunnel ### Nine Flexor Tendons - Flexor pollicis longus (radial side) - Four flexor digitorum superficialis tendons (middle/superficial layer) - Four flexor digitorum profundus tendons (deep layer) ### Median Nerve - Enters tunnel superficial and radial to tendons - Most superficial structure beneath TCL - Becomes compressed against rigid TCL roof with wrist flexion - Shows hourglass constriction at compression site - Proximal swelling (pseudoneuroma) may develop ## Critical Neural Anatomy ### Palmar Cutaneous Branch - **Origin**: Median nerve in distal forearm 5cm proximal to wrist crease - **Course**: Emerges between FCR and palmaris longus, passes superficial to TCL - **Distribution**: Thenar skin over thenar eminence - **Surgical relevance**: Injured if incision extends proximal to wrist crease - causes painful neuroma in 2-3% ### Thenar Motor Branch (Recurrent Motor Branch) - **Origin**: Radial side of median nerve 1cm distal to TCL distal edge - **Variants**: Extraligamentous 50%, subligamentous 31%, transligamentous 23% - **Distribution**: Abductor pollicis brevis, opponens pollicis, superficial head flexor pollicis brevis - **Surgical relevance**: Protected by ulnar-sided TCL division 3-5mm from radial edge ### Common Digital Nerves - Branch from median nerve 1-2cm distal to TCL - Supply palmar digital nerves to thumb, index, long, radial ring fingers - Lie deep to superficial palmar arch - Visible at base of fat pad distal to TCL ## Vascular Anatomy ### Superficial Palmar Arch - **Location**: Crosses palm 2-3cm distal to TCL at Kaplan's cardinal line - **Formation**: Ulnar artery continuation with variable contributions from median artery (5%), radial artery (35%) - **Branches**: Common digital arteries to fingers - **Surgical relevance**: Injury risk if dissect beyond Kaplan's line ### Persistent Median Artery - Present in 5-10% of population - Travels with median nerve through carpal tunnel - Can thrombose causing acute CTS - May require excision if symptomatic ## Surface Landmarks ### Kaplan's Cardinal Line - From apex of thumb-index web space to hook of hamate - Marks level of superficial palmar arch crossing - Distal limit of safe dissection ### Thenar Crease - Boundary between thenar eminence and palm - Incision stays ulnar (5mm) to this line - Protects thenar motor branch territory ### Ring Finger Axis - Longitudinal line through center of ring finger - Alignment for skin incision - Avoids motor branch radially and hypothenar neurovascular structures ulnarly ## Open vs Endoscopic Techniques ### Open Technique (Traditional) **Advantages**: - Direct visualization of anatomy - Complete release ensured - Lower learning curve - Can address anomalies (persistent median artery, ganglion, tumor) - Lower nerve injury rate (0.1-0.3% vs 0.3-0.5% endoscopic) **Disadvantages**: - Larger incision (2-3cm vs 1-2cm) - More pillar pain initially (30-40% vs 20-30%) - Longer return to grip strength (3-6 months vs 2-4 months) - Scar tenderness (20-25%) ### Endoscopic Technique (Single/Two-Portal) **Advantages**: - Smaller incision, less scar - Quicker return to grip activities (2-4 weeks vs 4-6 weeks) - Less pillar pain - Earlier return to work (1-2 weeks vs 2-4 weeks) **Disadvantages**: - Higher learning curve - Cannot visualize thenar branch directly - Higher incomplete release rate initially - Cannot address mass lesions - Higher equipment cost - Contraindicated in revision cases, anomalous anatomy **Outcomes**: Meta-analyses show equivalent symptom relief at 6 months; endoscopic has earlier return to function but higher initial incomplete release rate ## Anesthesia Options ### WALANT (Wide Awake Local Anesthesia No Tourniquet) **Technique**: 10ml 1% lidocaine with 1:100,000 epinephrine injected subcutaneously 20 minutes before incision **Advantages**: - Patient can demonstrate active finger motion confirming release - No tourniquet discomfort - Lower cost - Suitable for outpatient clinic setting - Patient feedback during surgery **Disadvantages**: - Requires cooperative patient - Distorted anatomy from local infiltration - Epinephrine contraindication myth (now disproven) ### Local Anesthesia with Tourniquet - Standard approach for most surgeons - Better hemostasis and visualization - 250mmHg arm tourniquet for 20-30 minutes ### Regional Block (Axillary/Supraclavicular) - For anxious patients - Longer postoperative analgesia - Requires anesthesia support ### General Anesthesia - Bilateral simultaneous cases - Patient preference/anxiety - Medical conditions requiring controlled airway ## Incision Variations ### Standard (Preferred): Ring Finger Axis - 2-3cm longitudinal - Starts at wrist crease (not proximal) - Extends to Kaplan's line - Ulnar to thenar crease by 5mm - Best visualization, lowest complication rate ### Mini-Open - 1.5-2cm incision - Requires good lighting and retraction - Similar outcomes to standard if complete release achieved ### Extended (Revision Cases) - 4-5cm incision - Extends 2cm proximal into forearm - For revision or severe cases - Better proximal release visualization ## TCL Division Techniques ### Distal-to-Proximal (Recommended) - Start at distal edge where fat pad visible - Safest approach - Grooved director protection - Divide on ulnar side 3-5mm from radial edge ### Proximal-to-Distal - Higher nerve injury risk - Used by some surgeons in revision - Not recommended for standard cases ### Complete Division vs Fenestration - Complete division is standard - Fenestration (multiple small cuts) has higher recurrence - Never perform TCL repair ## Level 1 Evidence ### Conservative vs Surgical Treatment **Jarvis et al. (2012) - Cochrane Review**: - Surgical treatment superior to splinting at 6 months - NNT = 3 for complete symptom resolution - Surgical benefits maintained at 1 year **Gerritsen et al. (2002) - JAMA**: - RCT comparing surgery vs splinting - Surgery: 90% success at 18 months - Splinting: 75% success at 18 months - Crossover rate from splinting to surgery: 40% ### Open vs Endoscopic Release **Scholten et al. (2007) - Cochrane Review**: - No difference in symptom relief at 3 months or later - Endoscopic: quicker return to work (6 days earlier) - Open: lower incomplete release rate - Similar complication rates overall **Vasiliadis et al. (2014) - Meta-analysis**: - 28 RCTs, 2,586 hands - Endoscopic: less scar tenderness, earlier grip strength recovery - No difference in CRPS, nerve injury, recurrence at 1 year ### Internal Neurolysis **Mackinnon et al. (1991) - J Hand Surg**: - RCT showing NO benefit from adding internal neurolysis - Potential harm from perineural scarring - Simple decompression sufficient - Internal neurolysis NOT recommended ### Steroid Injection vs Surgery **Hui et al. (2004) - Ann Intern Med**: - Surgery superior to steroid injection at 6 months (92% vs 67% improvement) - Injection useful for diagnostic confirmation - Temporary relief with injection (median 3 months duration) ## Outcome Studies ### Symptom Resolution Timeline **Night Symptoms**: Resolve within days to 2 weeks in 95% **Daytime Numbness**: Improves over 4-8 weeks, complete resolution in 85% by 3 months **Thenar Strength**: Gradual recovery over 3-12 months; permanent weakness in 10% with severe preoperative atrophy **Grip Strength**: Reduced 10-20% for 3-6 months, returns to baseline by 6-12 months **Pillar Pain**: Present in 30-40%, peaks at 2-4 weeks, resolves by 3 months in 90% ### Success Rates **Primary Surgery**: 85-95% excellent/good results at 1 year **Mild-Moderate CTS**: 95% success rate **Severe CTS with Atrophy**: 70-80% success (permanent thenar weakness in 20%) **Revision Surgery**: 60-75% success rate (lower than primary) ### Prognostic Factors (Poor Outcome) - Severe thenar atrophy preoperatively - Diabetes mellitus - Workers' compensation claim - Duration symptoms greater than 10 months - Age greater than 50 years - Bilateral severe disease - Cervical radiculopathy (double crush) ## Australian Context ### Medicare Item Numbers - **50124**: Carpal tunnel release, unilateral - $344.65 (2024) - **50127**: Carpal tunnel release, bilateral simultaneous - $516.95 (2024) ### AOANJRR Data - Not applicable (joint registry, not soft tissue procedure) ### PBS Medications - Methylprednisolone injection (diagnostic/therapeutic): Authority required for repeat injection within 6 months - Simple analgesia: paracetamol, NSAIDs (celecoxib PBS listed) ### eTG Guidelines - Surgical site infection prophylaxis: cephalexin 2g IV at induction OR - If penicillin allergy: vancomycin 25-30mg/kg IV - Single dose sufficient for clean procedures ### Grip Strength Recovery Normal postoperative course: grip strength reduced 10-20% for 3-6 months, gradual recovery to baseline by 6-12 months. Early grip strengthening (within 2 weeks) does NOT accelerate recovery and may increase pillar pain. **Management**: Reassure patient, avoid heavy gripping activities for 4-6 weeks, progressive strengthening from 6 weeks, putty exercises, formal hand therapy if plateau after 3 months. **Patient Position**: Supine with arm on hand table, shoulder abducted 90 degrees, elbow extended, forearm fully supinated. Tourniquet on upper arm (250mmHg) - optional for experienced surgeons or when using WALANT technique. No finger trap traction needed. **Surgical Approach**: Open technique through longitudinal incision in ring finger axis, ulnar to thenar crease, from distal wrist crease to Kaplan's cardinal line **Equipment**: Standard hand surgery tray including: #15 blade, fine-toothed forceps, tenotomy scissors, self-retaining retractor (Weitlaner or small Gelpi), grooved director or MacDonald elevator, bipolar cautery, 4-0 nylon or monocryl suture ### Step 1: Preoperative Marking & Patient Positioning Preoperative Marking & Patient Positioning: Mark THREE key landmarks with patient awake and hand positioned: (1) Kaplan's cardinal line - from apex of thumb-index web space to hook of hamate (palpable with wrist flexed, ulnar deviation) - this marks distal safe dissection limit where superficial palmar arch crosses, (2) Ring finger axis line - longitudinal extension of ring finger long axis into palm, (3) Thenar crease - visible boundary between thenar eminence and palm. Draw planned incision 2-3cm longitudinal starting AT distal wrist crease (never proximal), extending distally along ring finger axis to Kaplan's line, staying 5mm ULNAR to thenar crease. Position patient supine, arm abducted 90 degrees on hand table, fully supinated. **Technical Tip**: EXAM KEY: 'I mark Kaplan's cardinal line first with the wrist flexed and ulnarly deviated to make the hook of hamate prominent - I can palpate it on the ulnar side of the palm. This is my DISTAL safe limit as the superficial palmar arch crosses here and injury risks bleeding or digital ischemia. My incision follows the RING FINGER axis, staying ULNAR to the thenar crease by 5mm. This protects the thenar motor branch which in 50% of cases comes off the radial side of the nerve distal to the tunnel.' - Thenar branch injury if incision too radial (less than 5mm from thenar crease) - causes permanent thumb opposition weakness - Superficial palmar arch injury if extend distal to Kaplan's line - bleeding, hematoma, digit ischemia - Wrong hand/site surgery - WHO surgical safety checklist essential with patient, surgeon, nurse verification before prep - Improper positioning causing brachial plexus stretch injury - ensure shoulder abduction less than 90 degrees, padding under elbow ### Step 2: Anesthesia & Tourniquet Setup Anesthesia & Tourniquet Setup: Select anesthesia based on patient factors and surgeon preference: (1) Local anesthesia: 1% lignocaine with 1:100,000 adrenaline, 5-10ml injected subcutaneously along planned incision, (2) WALANT (wide-awake local anesthesia no tourniquet): 10ml 1% lidocaine with 1:100,000 epinephrine injected 20-30 minutes before incision allowing patient participation and active finger motion testing intraoperatively, (3) Regional block: axillary or supraclavicular brachial plexus block providing complete arm anesthesia, or (4) General anesthesia for anxious patients or bilateral simultaneous cases. If using tourniquet: apply to upper arm with adequate padding, exsanguinate limb with elevation (1 minute) or Esmarch bandage, inflate to 250mmHg for adults. Mark final incision: 2-3cm longitudinal, starting precisely AT distal wrist crease level (NEVER proximal), extending distally to but NOT beyond Kaplan's line, in ring finger axis staying 5mm ulnar to thenar crease. **Technical Tip**: EXAM KEY: 'I prefer WALANT for cooperative patients as it allows me to observe active finger movement at the end confirming complete TCL release and demonstrating immediate symptomatic improvement. The historical myth about epinephrine causing finger necrosis has been thoroughly debunked - modern evidence shows it is safe in digital/hand surgery. If using tourniquet, I inflate to 250mmHg after exsanguination by elevation for 60 seconds. My incision is precisely 2-3cm from the distal wrist crease to Kaplan's line - I never extend proximal to the wrist crease.' - Tourniquet-related nerve injury if prolonged greater than 90 minutes - causes neuropraxia, rarely permanent - Lidocaine toxicity if dose exceeds 4.5mg/kg plain (7mg/kg with adrenaline) - presents as perioral tingling, seizures, cardiac arrhythmias - Inadequate anesthesia causing patient movement during critical dissection - ensure complete block before starting - WALANT: distorted anatomy from local infiltration - wait full 20-30 minutes for vasoconstriction before incision ### Step 3: Skin Incision Skin Incision: Incise skin sharply with #15 blade held perpendicular to skin surface. Stay precisely in ring finger axis, 5mm ulnar to thenar crease. Length 2-3cm from distal wrist crease (starting AT crease, not proximal) extending to Kaplan's line distally. Make deliberate single smooth stroke through epidermis and dermis to subcutaneous fat level. Use fine-toothed forceps (Adson or similar) to handle skin edges gently - avoid crushing. Achieve hemostasis of skin edge bleeders with bipolar cautery using lowest effective setting, keeping cautery tips away from deeper structures. **Technical Tip**: EXAM KEY: 'I make a precise skin incision staying ULNAR to the thenar crease by 5mm and starting exactly AT the wrist crease, NOT proximal to it. The palmar cutaneous branch of the median nerve branches from the main trunk 5cm proximal to the wrist and runs between FCR and palmaris longus, staying radial to my incision line. If I extend even 5mm proximal to the wrist crease, I enter the territory of this branch and risk creating a painful neuroma in 2-3% of cases.' - Palmar cutaneous branch injury - occurs in 2-3% if incision extends proximal to wrist crease, causes painful neuroma requiring excision and nerve burial - Aberrant superficial thenar branch (2-3% run superficial to TCL) - must visualize subcutaneous tissue before deeper dissection to identify this rare variant - Excessive skin edge handling causing necrosis - use fine forceps gently on dermis only, not epidermis - Inadequate hemostasis causing obscured field or hematoma - achieve complete hemostasis at each layer ### Step 4: Subcutaneous Dissection Subcutaneous Dissection: Dissect through subcutaneous fat using tenotomy scissors in spreading technique or scalpel blade. Divide vertical fibrous septa connecting skin to palmar aponeurosis. Identify palmaris brevis muscle fibers crossing field obliquely from hypothenar side (small thin muscle from ulnar TCL edge to hypothenar skin) - may divide if obscuring field. Identify and protect any visible superficial veins with bipolar cautery or gentle retraction. Maintain hemostasis throughout. Deepen dissection through subcutaneous layer until reaching palmar aponeurosis - recognized as glistening white sheet with longitudinal fiber orientation. **Technical Tip**: EXAM KEY: 'The subcutaneous fat contains vertical fibrous septa (retinacula cutis) connecting skin to deeper fascia which I divide carefully with spreading scissors technique. I identify palmaris brevis muscle crossing superficially from the hypothenar side - this small muscle can be divided if needed without consequence. At this level I'm looking for any aberrant motor branch variant running superficially - seen in 2-3% where the thenar branch runs SUPERFICIAL to TCL rather than deep to it.' - Premature deep dissection through palmar aponeurosis - risk of nerve injury if advance too quickly - Failure to recognize aberrant superficial motor branch - look for small nerve crossing superficial plane before proceeding deeper - Excessive cautery in subcutaneous plane - increases scar formation and skin edge necrosis risk - Dividing palmaris brevis too aggressively - can cause bleeding from small vessels, usually inconsequential but maintain hemostasis ### Step 5: Identify & Divide Palmar Aponeurosis Identify & Divide Palmar Aponeurosis: Identify palmar aponeurosis - glistening white triangular fibrous sheet extending distally from palmaris longus tendon (if present) with LONGITUDINAL fiber orientation. This lies SUPERFICIAL to transverse carpal ligament - they are TWO distinct structures. Incise aponeurosis longitudinally in exact line with skin incision using scalpel or scissors. Divide full length of wound (2-3cm). Insert self-retaining retractor (Weitlaner with 2-3 sharp prongs or small Gelpi) to hold wound edges apart providing exposure. Bluntly separate aponeurosis from underlying TCL to expose the ligament clearly. **Technical Tip**: EXAM KEY: 'The palmar aponeurosis is superficial to the transverse carpal ligament - these are TWO separate layers that must be divided sequentially. The aponeurosis has LONGITUDINAL fibers running distal from the palmaris longus, whereas the TCL has TRANSVERSE fibers running radial-ulnar between the carpal bones. This is a key distinction. I incise the aponeurosis longitudinally first to expose the underlying TCL which is thicker (2-3mm vs 1mm), more robust, and has the characteristic transverse fiber pattern.' - Confusion between aponeurosis and TCL causing premature deep incision - TCL is deeper, thicker, and has transverse (not longitudinal) fibers - Nerve injury if cut too deep thinking aponeurosis is TCL - always verify fiber direction before deeper cutting - Inadequate aponeurosis division leaving distal bands - contributes to incomplete release syndrome - Self-retaining retractor prongs causing skin edge necrosis - place carefully on dermis not epidermis, avoid excessive tension ### Step 6: Expose Transverse Carpal Ligament Expose Transverse Carpal Ligament: Clear soft tissue and areolar tissue off surface of TCL using blunt dissection with closed scissors spreading or elevator. TCL is thick (2-3mm), glistening white, with characteristic TRANSVERSE fibers running radial-ulnar. Length 2-3cm proximal-distal. Insert self-retaining retractor to maintain exposure. Identify DISTAL edge of TCL carefully - key landmark is the FAT PAD visible at distal margin where TCL ends and superficial palmar arch territory begins. This fat pad is extrasynovial fat overlying the common digital neurovascular bundles. Palpate distal edge with elevator to confirm transition from firm ligament to soft fat. This distal edge is the SAFEST starting point for TCL division. **Technical Tip**: EXAM KEY: 'The TCL has characteristic TRANSVERSE fibers running between the scaphoid tubercle and trapezium radially to the pisiform and hook of hamate ulnarly - this distinguishes it from the LONGITUDINAL fibers of palmar aponeurosis superficially. I identify the DISTAL edge first by finding the fat pad - this yellow adipose tissue marks where the ligament ends. This is my safest starting point for division as the digital nerves branch 1-2cm distal to this and the superficial arch crosses 2-3cm distal at Kaplan's line. Starting distally and working proximal is much safer than starting proximal where the nerve is more adherent.' - Starting division proximally instead of distally - higher risk of median nerve injury as nerve may be adherent to proximal TCL undersurface - Incomplete exposure leading to partial division - most common technical error causing persistent symptoms - Confusing distal TCL edge with proximal edge if exposure inadequate - ensure full length visualized - Excessive retraction on radial side - can stretch thenar motor branch causing temporary or permanent neuropraxia ### Step 7: Identify Thenar Motor Branch (if visible) Identify Thenar Motor Branch (if visible): Before dividing TCL, carefully inspect for thenar motor branch (recurrent motor branch) at distal TCL edge. In 50% (extraligamentous variant), it branches after median nerve exits tunnel and may be visible coursing radially at distal edge toward thenar muscles (APB, opponens, superficial FPB). In 31% (subligamentous), it's under TCL and not visible until after division. In 23% (transligamentous variant), it actually pierces THROUGH the TCL substance and may be visible on ligament surface as small nerve (1-2mm diameter) with radial course. If transligamentous variant identified, mark its position with marking pen or remember location - this area must be avoided during division. **Technical Tip**: EXAM KEY: 'If I can see the thenar motor branch, I carefully note its exact position. In 50% of cases (extraligamentous) it exits distal to the TCL and runs radially toward the thenar muscles. In 23% (transligamentous variant) it actually pierces THROUGH the ligament and I may see it on the surface. This is critical to recognize BEFORE cutting. Regardless of which variant is present, I will divide the TCL on the ULNAR side, keeping my division line 3-5mm from the radial edge. This stays away from the thenar branch in ALL variants and is the key safety principle.' - Transligamentous variant (23% incidence) - motor branch pierces TCL and is directly at risk during division if not identified - Failure to identify visible branch before cutting - if seen, must modify division line to stay even more ulnar - Excessive radial retraction while looking for branch - can cause traction injury to branch if present - Assuming no visible branch means extraligamentous - may be subligamentous or transligamentous not yet visible ### Step 8: Initial TCL Division - Distal Edge Initial TCL Division - Distal Edge: Start at DISTAL edge where fat pad is clearly visible. Make small (3-5mm) longitudinal incision in TCL at distal edge under direct vision using #15 blade tip, cutting on ULNAR side of ligament midline (3-5mm from radial edge). Insert grooved director (Freer elevator or similar) or MacDonald dissector through this small opening, advancing UNDER the TCL from distal to proximal to protect median nerve which is immediately deep to ligament. The groove faces superficially protecting nerve on deep surface. Ensure director glides smoothly without resistance indicating it's in correct plane between TCL (superficial) and median nerve (deep). If resistance met, withdraw and reposition - forcing can injure nerve. **Technical Tip**: EXAM KEY: 'I start at the DISTAL edge where there's a visible fat pad for safety - this is the lowest-risk area as the nerve is beginning to branch into digital nerves and is less adherent. I make a small controlled opening with my blade tip on the ULNAR side, then insert my grooved director underneath sliding it proximally. The director has a groove facing up (superficial) so the blade will rest in this groove away from the nerve underneath. This is the critical protective maneuver. I confirm smooth passage - if I feel resistance, I stop and reassess rather than forcing which could injure the nerve.' - Median nerve injury if cut without grooved director protection - most devastating complication - Incomplete distal release if don't extend to true distal edge at fat pad - causes persistent symptoms - Digital nerve injury if initial incision made too far distally beyond fat pad into nerve branching zone - Grooved director in wrong plane (superficial to TCL or through nerve) - must feel smooth glide in correct tissue plane ### Step 9: Complete TCL Division - Distal to Proximal Complete TCL Division - Distal to Proximal: With grooved director firmly positioned protecting median nerve deep surface, divide TCL longitudinally from distal to proximal. Cut directly on the director in its groove using #15 blade or tenotomy scissors. Maintain division on ULNAR side of midline (3-5mm from radial edge) to avoid thenar branch territory radially. Make deliberate controlled cuts with blade tip riding in director groove. Maintain director position throughout entire division - do NOT remove until complete. Extend division full length of TCL (2-3cm) until reaching proximal extent where TCL becomes continuous with antebrachial fascia in forearm. Visualize TCL edges separating as division progresses, exposing underlying median nerve which should appear pink-white with visible fascicular pattern. **Technical Tip**: EXAM KEY: 'I divide on the ULNAR side of the ligament, keeping my incision 3-5mm from the radial edge. This protects ALL three thenar branch variants: in extraligamentous (50%) the branch exits distally on radial side so staying ulnar avoids it; in subligamentous (31%) the branch runs under the radial TCL edge so ulnar division stays away; in transligamentous (23%) the branch pierces through radial TCL so ulnar division avoids it. I maintain my grooved director deep to TCL throughout the entire division to protect the nerve which is immediately underneath and may be adherent in chronic severe cases.' - Median nerve laceration - most devastating complication (0.1-0.3%), causes permanent sensory/motor loss requiring immediate microsurgical repair - Thenar branch injury - causes permanent thumb opposition/abduction weakness (0.5-1%), may require tendon transfers if complete - Incomplete division - commonest cause of surgical failure (30-40% of failures), results from not extending division full length - Director slipping out of position during cutting - maintain constant awareness of director position, reposition if any doubt ### Step 10: Confirm Complete Distal Release Confirm Complete Distal Release: Visualize distal extent of release thoroughly. Should see: (1) Fat pad clearly visible as yellow adipose tissue, (2) Common digital nerves branching from median nerve approximately 1-2cm distal to original TCL distal edge - typically three branches (to thumb, index-long common digital, long-ring common digital), (3) Superficial palmar arch visible approximately 2-3cm distal to original TCL edge running transversely, and (4) TCL edges separated with clear gap. Divide any remaining distal fascial bands or aponeurotic fibers that may cause residual compression. Use scissors or blade on elevator to divide these bands under direct vision. Do NOT extend dissection beyond Kaplan's line (superficial arch injury risk). If any question of incomplete distal release, extend division further until certain all compressing structures divided. **Technical Tip**: EXAM KEY: 'Complete distal release is confirmed by three findings: first, seeing the fat pad clearly; second, visualizing the digital nerves branching from the median nerve; and third, seeing the superficial palmar arch crossing approximately 2-3cm distal to where the TCL ended. I divide any remaining fascial bands or distal aponeurotic fibers that could cause residual compression. However, I am very careful NOT to dissect beyond Kaplan's cardinal line which I marked preoperatively - this is where the superficial arch crosses and further dissection risks vascular injury.' - Superficial palmar arch injury if dissect too far distally beyond Kaplan's line - causes bleeding, hematoma, rarely digital ischemia requiring vascular repair - Incomplete release of distal TCL or aponeurotic bands - causes persistent symptoms requiring revision, accounts for significant portion of failures - Digital nerve injury with aggressive distal dissection - nerves branch 1-2cm distal to TCL and can be injured if dissect blindly - Persistent median artery injury (present in 5-10%) - may be thrombosed or require ligation if bleeding, usually inconsequential ### Step 11: Confirm Complete Proximal Release Confirm Complete Proximal Release: The antebrachial fascia (forearm deep fascia) is continuous with TCL proximally and can cause persistent compression if not released. Visualize proximal extent of TCL division. If antebrachial fascia appears tight or constricting, extend release proximally 1-2cm into forearm under direct vision using scissors or blade on elevator. Divide fascia longitudinally in line with TCL division, staying on ulnar side. Perform 'accordion test' for complete release: compress median nerve gently with elevator or forceps then release - nerve should visibly expand (like accordion bellows opening) when pressure released, indicating adequate decompression. Absence of accordion sign suggests incomplete release requiring further proximal or distal extension. **Technical Tip**: EXAM KEY: 'Incomplete PROXIMAL release is the single most common technical error causing persistent postoperative symptoms, accounting for 30-40% of surgical failures. The antebrachial fascia is continuous with the TCL proximally and I must ensure it is adequately divided. I extend my release 1-2cm proximally into the forearm fascia under direct vision. The accordion test is reliable - I gently compress the nerve then release, and the nerve should visibly expand indicating adequate pressure relief. If the nerve doesn't expand, I haven't released enough and must extend the division further proximally or distally until I see this sign.' - Incomplete proximal release - single most common cause of persistent symptoms (30-40% of surgical failures), requires revision surgery - Blind proximal dissection without visualization - can injure median nerve or palmar cutaneous branch proximally - Extending too far proximal (greater than 2-3cm) - no additional benefit and increases morbidity, scar tenderness, wound complications - Palmar cutaneous branch injury if extend proximal AND radial - branch crosses 5cm proximal to wrist between FCR and PL ### Step 12: Inspect Median Nerve & Identify Pathology Inspect Median Nerve & Identify Pathology: Systematically inspect median nerve for: (1) Hourglass deformity at previous compression site under TCL - confirms correct level of decompression, (2) Proximal swelling (pseudoneuroma) from chronic compression - should be visible proximal to hourglass if severe longstanding CTS, (3) Color - should be pink/white indicating viable nerve, dark brown suggests ischemia, (4) Fascicular pattern - should be visible through epineurium as longitudinal bundles, (5) Pathological anomalies including persistent median artery (5-10% incidence, travels with nerve, may be thrombosed), bifid median nerve (2% incidence, two separate nerve trunks), anomalous muscles (FDS to index, anomalous lumbricals crossing tunnel), ganglia, lipomas, gout tophi, or tumors. Note thenar branch origin if visible. Do NOT perform internal neurolysis (opening epineurium and separating fascicles) or epineurotomy as Level 1 evidence shows no benefit and potential harm from perineural scarring. **Technical Tip**: EXAM KEY: 'I inspect the nerve carefully for the classic hourglass constriction at the compression site - this confirms I've decompressed at the correct level. I also look for proximal pseudoneuroma swelling indicating chronic severe compression. I do NOT perform internal neurolysis or epineurotomy despite older teaching suggesting this might help. Mackinnon's 1991 Level 1 RCT definitively showed NO benefit from internal neurolysis and potential harm from perineural scarring. Simple decompression by dividing the TCL is sufficient treatment. The nerve will remodel over 3-12 months without needing manipulation.' - Missed space-occupying pathology (ganglion, lipoma, gout tophus, tumor) causing compression - requires excision for symptom relief - Nerve damage from unnecessary internal neurolysis - increases scarring, may worsen outcome - Persistent median artery thrombosis (rare) - if large and causing mass effect may need excision - Bifid nerve variant (2%) - may require division of persistent TCL bridge between nerve trunks for complete decompression ### Step 13: Hemostasis & Tourniquet Release Hemostasis & Tourniquet Release: Release tourniquet if used (deflate completely). Wait 2-3 minutes for reactive hyperemia to reach maximum effect so all potential bleeders are identified. Systematically identify and cauterize all bleeding vessels with bipolar cautery using lowest effective setting. Check specifically for: (1) Superficial palmar arch branches distally - usually small arterioles but can cause hematoma, (2) TCL edge vessels - multiple small vessels in ligament substance, (3) Skin edge bleeders from subcutaneous vessels, and (4) Any venous oozing from subcutaneous veins. Keep bipolar cautery tips away from median nerve and thenar branch (minimum 5mm distance). Irrigate wound with normal saline to identify any additional bleeding sources. Ensure completely dry field before closure - hematoma causes pain, delays recovery, and can rarely recompress nerve. **Technical Tip**: EXAM KEY: 'I release the tourniquet and achieve meticulous hemostasis - this is a critical step that inexperienced surgeons sometimes rush. Hematoma causes significant pain, delays recovery by weeks, and in rare cases can actually recompress the nerve causing recurrent symptoms. I wait a full 2-3 minutes after tourniquet release for reactive hyperemia to peak, then systematically cauterize every bleeder with bipolar cautery. I keep the cautery tips at least 5mm away from the median nerve and particularly the thenar branch radially to avoid thermal injury which can cause permanent neuropraxia.' - Hematoma formation (2-5% incidence) - causes pain, swelling, delayed recovery, rarely recompresses nerve requiring drainage - Arterial bleeding from superficial palmar arch branches - can be brisk requiring ligation if cautery insufficient - Thermal injury to median nerve or thenar branch from cautery too close - causes neuropraxia, potentially permanent - Missed bleeding source causing delayed hematoma - ensure complete hemostasis, check wound after patient movement ### Step 14: Wound Closure Wound Closure: Close SKIN ONLY using either: (1) 4-0 nylon interrupted simple or vertical mattress sutures (5-6 sutures for 2-3cm wound) with removal at 10-14 days, or (2) 4-0 monocryl subcuticular running suture for better cosmesis (no removal needed, absorbs by 3-4 weeks). Space sutures 3-4mm apart for adequate apposition. Do NOT close or repair palmar aponeurosis - leave open. Do NOT repair or reconstruct TCL - this would recreate the compression and negate the entire decompression, increasing recurrence risk. The TCL remnant edges gradually separate 5-8mm with wrist motion over subsequent weeks, maintaining decompression permanently. In acute CTS (trauma, compartment syndrome), some surgeons leave skin open with delayed closure at 3-5 days to prevent recurrent compartment syndrome. **Technical Tip**: EXAM KEY: 'I close skin only - the TCL is absolutely NOT repaired as this would recreate the compression and increase recurrence dramatically. There is no benefit to repairing or reconstructing the TCL. The palmar aponeurosis is also left unrepaired. After skin-only closure, the TCL remnant edges gradually separate by 5-8mm with normal wrist motion and this separation is permanent, maintaining decompression indefinitely. Some older techniques advocated TCL repair or reconstruction to prevent bowstringing - this is outdated and contraindicated as it causes recurrent compression.' - TCL repair or reconstruction - dramatically increases recurrence rate, causes pillar pain, and completely negates the decompression - Wound dehiscence if closure too tight or under tension - use adequate number of sutures with proper spacing - Skin edge necrosis if sutures too tight or tissue handled traumatically - use fine sutures with minimal tension - Infection risk if closure performed in contaminated or inadequately hemostatic field - ensure dry clean field ### Step 15: Dressing & Postoperative Instructions Dressing & Postoperative Instructions: Apply non-adherent dressing (Adaptic or similar) directly to wound. Place bulky soft gauze dressing (fluffs) over wound providing padding and compression. Wrap with crepe or elastic bandage from fingertips to mid-forearm providing gentle compression. Position wrist in neutral (0 degrees extension/flexion) - avoid forced dorsiflexion which stretches nerve. Plaster or thermoplastic splint is OPTIONAL and not mandatory (older practice was routine splinting, modern evidence shows no benefit). Elevate hand above heart level continuously for first 48 hours to minimize swelling. Provide written and verbal postoperative instructions: (1) Immediate finger ROM - full active fist making and extension from day 1 to prevent stiffness, (2) Wrist ROM from day 3-5 - gentle flexion/extension, avoid forced movements, (3) Gentle hand use for light activities immediately (eating, grooming), (4) Avoid heavy grip activities or pressure on palm for 4-6 weeks to prevent pillar pain, (5) Elevation above heart when not using hand, (6) Suture removal 10-14 days, (7) Return immediately for excessive pain, swelling, numbness, fever, or wound drainage. **Technical Tip**: EXAM KEY: 'I apply a bulky dressing for compression and padding but do NOT routinely splint the wrist - modern evidence shows routine splinting provides no benefit and may increase stiffness. Early mobilization is strongly encouraged: immediate full finger ROM (fist making) from day 1, wrist ROM from day 3-5. The patient can use the hand for light activities immediately (self-care, eating) but should avoid heavy gripping activities or pressure directly on the palm for 4-6 weeks. This balance allows early return to function while avoiding pillar pain which is worsened by excessive pressure on the healing TCL remnant edges.' - Excessive or prolonged splinting - causes wrist and finger stiffness, delays recovery, no proven benefit - Inadequate elevation - increases swelling, pain, and risk of hematoma formation - Dressing too tight - can cause compartment syndrome (very rare but reported), finger ischemia - Inadequate patient education - patients who resume heavy gripping too early have worse pillar pain and longer recovery **Immediate (0-2 weeks)**: Bulky dressing maintained for 3-5 days then changed to lighter dressing. Immediate finger ROM encouraged - full active fist making and extension exercises hourly. Wrist ROM begins day 3-5 with gentle flexion/extension (avoid forced movements). Hand elevation above heart when not in use. Light activities of daily living permitted (eating, grooming, typing). Avoid heavy gripping or palm pressure. Wound check at 5-7 days. Pain management with paracetamol and NSAIDs (avoid opioids unless severe pain). Night symptoms typically resolve within 2-7 days providing immediate relief. **Early (2-6 weeks)**: Sutures removed 10-14 days. Scar massage initiated from 3 weeks (gentle circular massage with moisturizer 5 minutes three times daily) to prevent adherent scar and hypertrophic scar formation. Progressive wrist ROM advancing to full flexion/extension. Gentle grip strengthening with soft putty from 3-4 weeks. Return to desk work/light duties 1-2 weeks. Avoid heavy manual work until 6 weeks. Daytime numbness progressively improves over 4-8 weeks with 85% complete resolution by 3 months. **Intermediate (6 weeks-3 months)**: Progressive strengthening with therapy putty, grippers, resistance exercises. Return to manual labor/heavy work at 6 weeks if tolerated. Pillar pain peaks at 2-4 weeks then gradually resolves - 90% resolution by 3 months. Grip strength remains reduced 10-20% but progressively improves. Scar massage continues until scar mature and pliable (usually 3 months). **Long-term (3-12 months)**: Thenar muscle strength recovery gradual over 3-12 months in cases with preoperative atrophy. Complete recovery of thenar function occurs in 80% with moderate atrophy, but 20% with severe longstanding atrophy have permanent weakness. Grip strength returns to baseline by 6-12 months. Scar maturation complete by 6-12 months. Final outcome assessment at 6-12 months. **Expected Recovery Timeline**: - Night symptoms: resolve days to 2 weeks (95% patients) - Daytime numbness: improves 4-8 weeks, complete resolution 3 months (85%) - Pillar pain: peaks 2-4 weeks, resolves 3 months (90%) - Grip strength: reduced 10-20% until 3-6 months, baseline by 6-12 months - Thenar strength: gradual recovery 3-12 months, permanent deficit in 20% with severe atrophy - Return to desk work: 1-2 weeks - Return to manual work: 4-6 weeks - Return to unrestricted activities: 6-12 weeks ## References 1. **Jarvis SE, Morefield-Gale S, Brown JM, et al.** Carpal tunnel syndrome: surgical versus non-surgical treatment. *Cochrane Database Syst Rev.* 2012;7:CD001552. [Level 1 evidence - surgical superior to splinting at 6-12 months] 2. **Gerritsen AA, de Vet HC, Scholten RJ, et al.** Splinting vs surgery in the treatment of carpal tunnel syndrome: a randomized controlled trial. *JAMA.* 2002;288(10):1245-1251. [Level 1 RCT - surgery 90% success vs splinting 75% at 18 months] 3. **Scholten RJ, Mink van der Molen A, Uitdehaag BM, et al.** Surgical treatment options for carpal tunnel syndrome. *Cochrane Database Syst Rev.* 2007;4:CD003905. [Level 1 meta-analysis - open vs endoscopic equivalent outcomes at 6 months] 4. **Vasiliadis HS, Georgoulas P, Shrier I, et al.** Endoscopic release for carpal tunnel syndrome. *Cochrane Database Syst Rev.* 2014;1:CD008265. [Level 1 meta-analysis - 28 RCTs, 2,586 hands] 5. **Mackinnon SE, McCabe S, Murray JF, et al.** Internal neurolysis fails to improve the results of primary carpal tunnel decompression. *J Hand Surg Am.* 1991;16(2):211-218. [Level 1 RCT - no benefit from internal neurolysis, potential harm] 6. **Hui AC, Wong S, Leung CH, et al.** A randomized controlled trial of surgery vs steroid injection for carpal tunnel syndrome. *Ann Intern Med.* 2004;141(8):493-497. [Level 1 RCT - surgery superior at 6 months, 92% vs 67%] 7. **Lanz U.** Anatomical variations of the median nerve in the carpal tunnel. *J Hand Surg Am.* 1977;2(1):44-53. [Definitive anatomical study - thenar branch variants classification] 8. **Palmer AK, Toivonen DA.** Complications of endoscopic and open carpal tunnel release. *J Hand Surg Am.* 1999;24(3):561-565. [Comprehensive complication analysis] 9. **Kaplan EB.** Functional and surgical anatomy of the hand. 2nd ed. *JB Lippincott;* 1965. [Classic anatomical reference - Kaplan's cardinal line described] 10. **Chammas M, Boretto J, Burmann LM, et al.** Carpal tunnel syndrome - Part I (Anatomy, physiology, etiology and diagnosis). *Rev Bras Ortop.* 2014;49(5):429-436. [Comprehensive review - anatomy and pathophysiology]

Carpal Tunnel Release - Open Technique

Carpal Tunnel Release - Open Technique