In general all entrapmentshave any one of thefollowing basic structure –1.Fibro-osseous tunnels like• Carpal tunnel(median nerve)• Tarsal tunnel(posterior tibial nerve)• Suprascapular tunnel (suprascapular nerve)
2.Fibrotendinous arcade at theorigin of certain muscle-• Supinator(arcade of Frohse)• Flexor carpi ulnaris (cubital tunnel)• Flexor digitorum sublimis (sublimis bridge)• Common peroneal nerve entrapment• Anterior and posterior interosseous nerve entrapments• Piriformis syndrome
CARPAL TUNNEL• Earliest description of CTS was given by Sir James Paget in 1854• Fibro-osseous passageway in the anterior aspect of the wrist formed by the carpal bones and flexor retinaculum.• Floor volar radiocarpal ligament .• Roof Transverse Carpal Ligament(TCL), attaches medially to the pisiform and hook of the hamate and laterally to the scaphoid tuberosity and crest of the trapezium.• The TCL is approximately 3 to 4 cm in width and 2.5 to 3.5 mm in thickness and is 4 to 6 cm in length
• Contents 1.The median nerve and its vascular bundle, 2.Tendons- flexor digitorum superficialis(FDS), profundus (FDP) and flexor pollicis longus
ULNAR NERVE ENTRAPMENT• Henry Earle in 1816 was the first to report surgical treatment for ulnar nerve compression at elbow. In 1956, Feindel and Stratford proposed the designation “cubital tunnel” to describe the site of UN compression at the elbow.• Most common site of entrapment between the medial epicondyle and olecranon within the cubital tunnel• Roof cubital tunnel retinaculum or arcuate ligament of Osborne which extends from tip of the olecranon to the medial epicondyle.• Fibers oriented in transverse fashion and become taut with elbow flexion.• Floor capsule of the elbow joint and medial collateral ligament.• Walls medial epicondyle and olecranon.
DIFFERENT SITES OF ULNAR NERVE ENTRAPMENT IN ELBOW
POSTERIOR INTEROSSEOUS NERVE ENTRAPMENT• Terminal branch of radial nerve arising in front of the lateral epicondyle of elbow.• Supplies extensor carpi radialis brevis and supinator and enters arcade of Frohse which is the usual site of entrapment.• Arcade is a tough fibrotendinous ring like structure at the origin of supinator muscle.• Arcade is absent in full term fetuses and seen in 30% adults indicating that “the arcade is probably formed in the most proximal part of the superficial head of the supinator in response to repeated rotary movement of the forearm”• It passes in the dorsal aspect of forearm and supplies most of the extensors of hand and wrist.• No cutaneous branches
ANTERIOR INTEROSSEUS SYNDROME• principally a motor nerve• branch of median nerve in proximal forearm arising variably between the 2 heads of pronator teres, descends vertically in front of interosseous membrane between flexor digitorum profundus and flexor pollicis longus, supplies these 2 muscles and terminates by supplying the pronator quadratus.• The nerve can get entrapped due to fractures, penetrating wounds, constricting bands mostly near its origin.• In majority the cause is not found
ANATOMY RADIAL TUNNEL• Radial tunnel is the space SYNDROMEsurrounding the distal radialnerve and proximal PIN fromhumeroradial joint to withinthe supinator muscle.The tunnel is 5 cm long, is anterior toproximal radius.The floor is formed by capsule ofradial capitulum. The brachioradialis,ECRL and ECRB form lateral wall andbiceps and brachialis form the medialwall.
SUPRASCAPULAR ENTRAPMENT• Suprascapular nerve is a mixed nerve arising from superior trunk of brachial plexus.• Supplies supraspinatus, infraspinatus and sensory supply to capsule of shoulder joint.• Runs through posterior triangle of neck, parallel to inferior belly of digastric under trapezius, through suprascapular notch, below suprascapular ligament and into suspinous fossa. From there loops around the lateral angle of spine and enters deep surface of infraspinatus to supply it.• The nerve commonly gets trapped in the suprascapular notch, rarely in spinoglenoid notch
THORACIC OUTLET SYNDROME• Galen first described the presence of a cervical rib in 150 AD• The thoracic outlet refers to the communication of the thoracic cavity with the root of the neck.• There are three sites within the thoracic outlet where neurovascular compression may occur:• The interscalene triangle• The costoclavicular space• The subpectoral tunnel.The most important passageway clinically is interscalene triangle,bordered by anterior scalene muscle anteriorly, middle scalene muscleposteriorly and medial surface of the first rib inferiorly.Contains trunks of the brachial plexus and subclavian artery
TARSAL TUNNEL SYNDROME• The TT is a continuation of the deep posterior compartment of the calf into the posteromedial aspect of the ankle and the medial plantar aspect of the foot.• The TT is made up of two main compartments:• An upper (tibiotalar) and a lower (talocalcaneal) compartment.• Floor of the upper compartment posterior aspect of the tibia and the talus• The posterior tibial neurovascular bundle runs through this space with the tendons of the Tibialis Posterior, Flexor Digitorum Longus and Flexor Hallucis Longus. The lower compartment of the TT contains the abductor hallucis muscle.
• The tibial nerve passes within the upper compartment of the TT posterior to the tendons of the TP and FDL and the posterior tibial artery and vein.• The medial and inferior calcaneal nerves may arise proximal to, within or distal to the TT. 1. TIBIALIS POSTERIOR TENDON• The roof is formed by a 2. FDL TENDON 3. TIBIAL NERVE deep aponeurosis. 4. FLEXOR RETINACULUM 5. MEDIAL PLANTAR NERVE 6. LATERAL PLANTAR NERVE
PIRIFORMIS SYNDROME• Piriformis originates from the anteriorsurface of the sacrum and the superior marginof the greater sciatic notch. It also hasattachment to the capsule of the sacro-iliacjoint and also the sacrotuberous ligament.• Exits pelvis through greater sciatic notch, fibres inserted into the superior aspect of the greater trochanter of the femur• The sciatic nerve passes deep to piriformis in most cases (approximately 85% of people) but can pierce the piriformis itself, predisposing to piriformis syndrome and subsequent sciatica.• Even if the sciatic nerve runs deep to piriformis, spasm in this muscle put direct pressure on the nerve, causing the resultant pain and discomfort.
COMMON PERONEAL NERVE ENTRAPMENT• The common peroneal nerve after emerging out of the popliteal fossa courses around the fibular neck and passes through the fibro-osseous opening in the superficial head of the peroneus longus muscle at its origin which forms a sharp crescentric arch• This opening can be quite tough, and can result in the nerve angulating through it at an acute angle• Fibrous connective tissue secures the nerve to this proximal portion of the fibula, potentially compromising the nerve• This opening in peroneus longus is called fibular tunnel where the common peroneal nerve gets entrapped commonly
PATHOLOGY• The effect of nerve compression is mediated by ischemia and edema.1. Disruption of blood nerve barrier2.Dysfunction of intraneural circulation reversible3.Segmental demyelination4.Edema1.Epineural fibrosis irreversible2.Thickening of nerve3.Myelin sheath damage4.Axonal disruption
PREDISPOSING FACTORS Congenital narrowing of osseous canalthrough which the nerve traverses like increasedcarrying angle malunited epiphysis Thickening of overlying retinaculum due tosystemic diseases like hypothyroidism,occupation related like carpenters and musicianshaving thickened flexor retinaculum in the wrist
CAUSES1.Normal anatomy with abnormal contents• Tumors- intraneural neuroma, lipoma, Ganglion, schwannoma, hemangioma, neurofibroma, desmoid tumors, angiomas, fibrolipomatosis, hamartomas, vascular abnormalities. Exostosis, chondromatosis, Baker cysts- more commonly seenaround the knee in relation to the compression of the commonperoneal nerve• Congenital- Persistent median artery as in carpal tunnel• Rudimentary cervical rib in TOS• Anamolous fibrous bands
CAUSES2.Abnormal anatomy of the normal contents• Inflammation or edema of surrounding structures• Accessory or hypertrophic muscles• Varicosities• Tenosynovitis• Prominent C7 transverse process in TOS• Reflex spasm of the muscle like piriformis in piriformis syndrome• Abnormal course of the nerve through the muscle or its tendon –sciatic nerve through the piriformis• Altered biomechanics resulting from limb length discrepancy leading to stretching and shortening of the muscle like piriformis• Malunited fractures like fibular neck
Common Conditions Associated with Carpal Tunnel SyndromeMetabolic/endocrine: Anatomic:• Diabetes mellitus • Persistent median artery• Pregnancy • Anomalous tendons or muscles• Hypothyroidism • Congenital stenosis of the carpal tunnel• Acromegaly • Fracture and/or dislocation at the wrist• Renal failure Infectious:• Pyridoxine (vitamin B6) deficiency • Septic arthritisAutoimmune/inflammatory: • Lyme disease• Rheumatoid arthritis • Tuberculosis• Amyloidosis • Histoplasmosis• Sarcoidosis Neoplasm:• Tenosynovitis • Nerve sheath tumor • Ganglion cyst
Age and gender vary-• Carpal tunnel- Middle aged female• Thoracic outlet syndrome- young, thin female with a long neck and drooping shoulders• Meralgia Paresthetica- middle aged over-weight men• Athletes in general predisposed to cubital tunnel syndrome, thoracic outlet syndrome, piriformis syndromeOccupation : carpentry, painting, and musicians are moresusceptible for Ulnar nerve compressionMilitary personal wearing heavy belts -meralgia parestheticaPostural variation -Symptom aggravated by standing and walkingand relieved by rest in meralgia paresthetica
COMPLAINTS• Pain, numbness are the early symptoms.• weakness, wasting, deformity are the late symptoms.Certain syndromes have specific symptoms like• nocturnal increase in pain with disturbed sleep - Carpal tunnel syndrome and Tarsal tunnel syndrome• Vasomotor disturbances such as changes in skin color and temperature - thoracic outlet syndrome• Motor weakness may precede sensory disturbances because of the predominance of motor fibers within the Ulnar nerve as in Cubital tunnel• Frequent dropping of objects - Ulnar nerve involvement
SIGNS• Sensory loss in the distribution of the nerve• Wasting of the muscles supplied by the nerve• Deformities of the hand/leg due to selective involvement of the muscles like clawed hand in ulnar involvement, foot drop in common peroneal involvement• Trophic ulcers in the distribution of the nerve in long standing sensory nerve involvement• Flick sign- To relieve the symptoms, patients often “flick” their wrist as if shaking down a thermometer in Carpal tunnel syndrome
TINELS SIGNTapping of the nerve at the site of involvementproduces paresthesia all along the distribution ofthe nerve
PHALENS MANEUVERIt reproduces the symptoms in Carpaltunnel syndrome
ROOS TESTElevated arm stress test to induce reproduction of theneurological symptoms in Thoracic Outlet Syndrome
WRIGHT TESTProgressive shoulder abduction to reproduce thesymptoms in Thoracic Outlet Syndrome
ADSON TESTFull neck extension and head rotation toward the sidebeing examined, during deep inhalation, to detect areduction in radial pulse amplitude in thoracic outletsyndrome
WARTENBERG SIGNIn ulnar nerve compression the third volar interosseousmuscle is weak and allows the extensor digiti minimi to abductthe fifth finger during extension causing finger catching whileplacing the affected hand in pocket.
DIFFERENTIAL DIAGNOSIS OF CUBITAL TUNNEL SYNDROMEDifferential Diagnosis of Cubital Tunnel Syndrome• Spinal cord Cervical spondylotic myelopathy Cervical syrinx Cervical spinal cord tumor• Nerve root Motoneuron disease(Amyotrophic lateral sclerosis (ALS)-initial stages ) C8 or T1 radiculopathy• Peripheral nerve Brachial plexopathy (lower trunk or medial cord)• Ulnar nerve Nerve sheath tumor Ulnar nerve compression at the arcade of Struthers. Ulnar nerve entrapment at Guyons canal• Other Peripheral neuropathy Thoracic outlet syndrome
INVESTIGATIONSX-rays - To see for any fractures, osteophyte formation,hypertrophic changes, cervical ribUltrasound - to see for abnormal contents like tumors, cysts,varicosities, edema of the surrounding structures.• Refinements of the techniques has allowed direct visualization of neural structures and associated sites of constriction or compression.• Entrapped peripheral nerves appear swollen, hypo echoic or flattened.• Is found useful and highly sensitive is CTS, UN entrapment, suprascapular, axillary and radial neuropathies
ELECTROPHYSIOLOGY• Electrophysiology is an important investigation• EMG and NCSs use different means of measuring action potentials of nerve axons or muscle fibers• SNAP(Sensory nerve action potentials ) and CMAP(Compound Muscle Action Potential) are recorded on both the limbs for comparison and in different nerves of same limb to rule out symmetric involvement.• These recordings should be done across the suspected area of the lesion• Recording should be done by inching technique.• In entrapments generally the latency is increased, conduction velocity is reduced and amplitude is reduced in later stages.
CARPAL TUNNEL SYNDROME• Important objective information to support the diagnosis of CTS.• Palmar sensory latency - most sensitive test .• Distal motor latency may be normal in 25% of patients.• Sensory nerve action potentials (SNAPs) are either unrecordable or of low amplitude at the wrist.• Helpful in grading the severity of CTS.In mild CTS, SNAP or mixed nerve action potential (NAP)- prolonged SNAP amplitude- below the lower limit of normal.In moderate CTS, findings of mild CTS plus prolongation of median motor distal latencyIn severe CTS, median motor and sensory distal latencies-prolonged, absent SNAPsor mixed NAPs or absent or reduced thenar compound motor actionpotentials or both.• Fibrillations, reduced recruitment, and changes in motor unit potential are often seen in severe cases.
CUBITAL TUNNEL SYNDROME• Prolonged motor and sensory latency across the elbow but normal latency in the distal part of the forearm.• Motor conduction velocities of less than 50 m/sec across the elbow also suggest entrapment at the elbow.• Electromyography of ulnar-innervated muscles may show reduced voluntary motor units, fibrillations, increased insertional activity, and other electro physiologic signs of denervation
POSTERIOR INTEROSSEOUS NERVE ENTRAPMENT• Needle electromyographic examination- denervation potentials in innervated muscles and absence of same in muscles directly innervated by radial nerve localises lesion to PIN.• Further absence in extensor carpi radialis brevis and supinator localises to arcade of Frohse.• Nerve conduction velocity studies show slowing across entrapment site.
THORACIC OUTLET SYNDROME• In true neurogenic TOS,EMG shows reduced motor units under voluntary control in hand muscles.• Needle examination of cervical paraspinal muscles –normal• Maximal motor conduction velocity may be slowed in the median nerve but normal in the ulnar nerve, and distal motor latencies for both nerves are normal.• Compound motor action potentials(CMAP) over thenar muscles are reduced in situations of marked axonal loss, whereas those over the hypothenar muscles are generally normal.• Sensory nerve action potentials(SNAP) recorded at the median nerve in the wrist have normal amplitude and latency, but they are often small or absent from the ulnar nerve after stimulation of the fifth finger.• In disputed neurogenic TOS, electrophysiologic studies are normal.• Nerve conduction velocities(NCV) for the medial antebrachial cutaneous nerve abnormal in patients with neurogenic TOS in the absence of other electrophysiologic findings
TARSAL TUNNEL SYNDROME• Tibial motor nerve conduction-prolonged, distal onset latency when recorded over the abductor hallucis and abductor digit minimi.• Mixed nerve conduction studies of the medial and lateral plantar nerves- prolonged peak latency or slowed velocity• Sensory nerve conduction of the two nerves may be slowed or absent across the tarsal tunnel.
MAGNETIC RESONANCE IMAGING• Greater sensitivity in the detection of peripheral nerve inflammation.• MRI techniques useful in patients with normal electrophysiological studies or in those with an underlying systemic neuropathy altering the electrophysiological results.• A normal nerve appears isointense to muscle in all sequences• Nerve thickening or nerve enlargement on MRI signifies inflammation.• Nerve may be enlarged proximally to the point of constriction• Increased signal intensity within inflamed peripheral nerves seen on short tau inversion recovery (STIR) images or fat-suppressed T2- weighted spin echo images.• Muscles that are innervated by the distal portion of the entrapped nerves appear bright on T2 and STIR thus confirming the identity of the nerve.
Axial STIR image through the distal forearm of a patient who hassurgically confirmed AIN syndrome. In the T1-weighted image (A),atrophy of the PQ (arrows) is seen. In the STIR image (B),increased signal within the PQ is visible, but there is alsoincreased signal without atrophy in FDP1 and FDP2 (arrows).
MRI• May suggest adhesion of nerve to surrounding tissue.• Magnetic resonance neurography is useful in demonstrating nerve position in relation to an adjacent joint placed in varying degrees of flexion.• After denervation MRI changes in denerved muscle precedes the EMG change.• Inflammatory conditions of the nerves also enhance on T2 but the enhancement is more diffuse.• Inflammatory conditions, tumors and traumatic neuromas enhance with current contrast but entrapped nerves do not enhance.• Also useful in the detection of mass lesions
NEWER TECHNIQUES IN MRI• DTI(diffusion Tensor Imaging ) is used to track the nerves, can be used for viewing changes at the microscopic structure of the nerve at and proximal to the entrapment which are not seen on T2 or STIR• 3D pulse sequences-high quality image reformatting in all planes. It has been applied to brachial plexus and sciatic nerves and has shown promise for being able to show longitudinal images of nerves over long segments thus identifying areas of focal narrowing or extrinsic compression
(A) T1-weighted image of excised human median nerve, obtained on a 3-T magnetic resonance microscopy system.(B) Light microscopy of the same nerve. These are not seen in normal imaging techniques.
NEWER TECHNIQUES IN MRI• Newer agents like Gadoflurine –M (not yet available for human use) and Vasovist having longer clearance values from blood due to tight protein binding are seen to produce enhancement in demyelinating and degenerating peripheral nerves which otherwise fail to enhance on conventional contrast agents may become useful in entrapments also.• Magic angle effect-Water containing longitudinally arranged proteins as in nerves and collagen when makes an angle of 55⁰ with main magnetic field it appears more bright on T2 and STIR
CAN MRI REPLACE ELECTROPHYSIOLOGY?• In syndromes where the nerves are deep and recording is not practical MRI definitely is the preferred technique• IN CTS where both can be employed, many RCTs have been done to look for the sensitivity and specificity of the results of each of these 2 modalities. In CTS it can be concluded that MRI has some what inferior accuracy to nerve conduction studies but is preferred by patients as it is non invasive, fast and also contributes additional information.• In ulnar nerve entrapment at elbow MRI has a sensitivity of (>95%) as compared to nerve conduction studies (60-70%). Bland JD. Carpal tunnel syndrome. Curr Opin Neurol 2005;18:581–5. Vucic S,Cordato DJ, et al. Utility of magnetic resonance imaging in diagnosing ulnar neuropathy at theelbow. Clin Neurophysiol 2006;117:590–5
• In piriformis syndrome MRI has shown 93% specificity for two findings namely T2 hyperintense signal of the sciatic nerve in the sciatic notch and piriformis asymmetry• In peroneal nerve entrapment, MRI is useful in distinguishing this condition from L5 root involvement by demonstrating the additional involvement of Tibialis posterior and popliteus in L5 root involvement apart from involvement of TA,ED,PL in both cases. MRI can demonstrate causes like ganglionic cysts and origin of these cysts(joint vs. nerve)
NON-SURGICALGENERAL• Splints, physical therapy, ultrasound therapy, ice and heat therapy, diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs)• Corticosteroids (either oral or direct )• Avoid positions that trigger pain• Lifestyle modification: avoidance of activities that exacerbate or provoke symptoms• Correcting poor posture• Nerve blocks• Muscle denervation through targeted injection of botulinum toxin• Psychological counseling
SPECIFIC• Resting the affected shoulder as in suprascapular entrapment• Weight reduction in obese people in meralgia paresthetica• Physiotherapy-example, Piriformis stretching exercises• Sports massage techniques
LOCAL STEROID INJECTION• The benefit of steroid treatment is transient.• About 50% of the nerves become worse within 6 months and 90% within 18 months.• Only a small percentage (8%) of the nerves remain improved at the 2-years follow-up.Paolo Girlanda et al. Local steroid treatment in idiopathic carpal tunnel syndrome short- and long-term efficacy:Journal of Neurology Volume 240, Number 3, 187-190
SURGICAL TREATMENT• Release of the constriction is the main surgical treatment.• The timing of surgery, type and extent of surgery is much debated aspect.Patients with motor deficits invariably require surgicaldecompression at the earliest, if any improvement is expected.This is undebatable.Dilemma regarding timing and decision for surgery is present infollowing group of patients1. Patients with only pain2. Pain without motor symptoms with normal electrophysiology3. Controversial syndromes
SURGICAL OPTIONS FOR CTSMETHODS• OPEN REDUCTIONGoal is complete excision of flexor retinaculum.A 3- to 4-cm straight or slightly curvilinear incision, startingat distal wrist crease and ending at a point intercepting animaginary line (Kaplans) drawn from the distal border ofthe extended thumb to the pisiform prominence, in linewith the long axis of the radial side of the ring finger.TCL divided at midpoint, once median nerve visualized, TCLincised both proximally and distally. The distal TCL incisedtill deep palmar fat pad is visualized
In mini open approach, 1.5-3 cm incision is given.ENDOSCOPIC TECHNIQUES- Uniportal technique1.Okutsu technique2.Agee technique. Biportal technique1.Chow technique2.Brown technique
OPEN vs. ENDOSCOPIC SURGERY IN CTS• Cochrane collaboration did a systemic review of 33 studies looking at return to work or normal daily activity, complications. They found transient nerve dysfunction was more in endoscopic ones compared to open ones, the latter had more wound complications. They concluded that no strong evidence to suggest replacement of standard OCTR with ECTR.• In 2004,Thoma and colleagues performed meta-analysis and found no statistically significant difference in pain or return to work.• Atroshi and colleagues published a RCT. Primary outcome was severity of postoperative incisional or palmar pain and secondary outcomes were length of work absence ,severity of CTS symptoms and functional status at intervals up to 1 year. In the end they questioned the cost-effectiveness of endoscopy as there was no difference in the outcome Eichhorn J, Dietrich K. Open versus endoscopic carpal tunnel release. Results of a prospective study. ChirPraxis. 2003;61:279
ULNAR NERVE ENTRAPMENTTypes1. Simple decompression (with or without medial epicondylectomy)2. Anterior subcutaneous transposition3. Intramuscular transposition4. Submuscular transpositionSimple or in situ decompression- of the UN, which involvesunroofing of the cubital tunnel, is the easiest and mostcommonly used option.Once decompression is completed, the elbow is flexed andextended to look for nerve subluxation and stretch.
Anterior subcutaneous or sub muscular transposition• Complete external neurolysis of the Ulnar nerve(UN) must be performed.• Articular branches and small vessels tethering the UN need to be divided.• A distal segment of the medial intermuscular septum must be excised to prevent tethering or compression of the transposed UN• In anterior subcutaneous transposition, the nerve is brought anterior to the medial epicondyle, and a fascial sling is created to hold the nerve in place• In the case of submuscular transposition, the origin of the flexor- pronator mass is isolated and divided in a step-cut or Z-plasty configuration, with a proximal cuff of muscle and fascia left intact.• Arm is placed in a sling for approximately 3 weeks
• Recently, endoscope has been used to decompress the UN at the elbow. Through a 2 to 3 cm incision over the course of the UN at the elbow, it is possible to decompress up to 10 cm proximal and 10 cm distal to the medial epicondyle
INSITU DECOMPRESSION vs.TRANSPOSITION IN ULNAR ENTRAPMENT • In 2007, Zlowodzki and coauthors published a meta-analysis of four randomized controlled trials that comparing in situ decompression and anterior transposition • A total of 261 patients with an average follow-up of 21 months were included in this study. The results of this analysis found no significant difference in clinical outcome or postoperative nerve conduction velocity between in situ decompression, subcutaneous transposition, and sub muscular transposition • In initial cases at the end of insitu decompression with flexion and extension of the elbow if there is no tension in the nerve, there is no need for transposition • Transposition is often procedure of choice in recurrent cases or in patients with significant ulnar nerve subluxation Zlowodzki M, Chan S, Bhandari M, et al. Anterior transposition compared with simple decompression for treatment of cubital tunnel syndrome. A metaanalysis of randomized, controlled trials. J Bone Joint Surg Am. 2007;89:2591
SUPRASCAPULAR ENTRAPMENT• Sectioning of the suprascapular ligament is treatment of choice in people not improving with conservative treatment• Posterior approach is generally used• Anterior supraclavicular approach has not gained popularity• Sequence of recovery is pain relief followed by gain of motor strength, atrophy if at all reverses at the end• Arthroscopic and endoscopic methods have been developed and recent RCTs favor endoscopy as it is associated with less complicationsTubbs RS, Loukas M, Shoja MM, et al. Endoscopically assisted decompression of thesuprascapular nerve in the supraspinous fossa: a cadaveric feasibility study. Laboratoryinvestigation. J Neurosurg 2007;107:1164–7.
ANTERIOR INTEROSSEUS SYNDROME• Conservative management for 8-12 weeks as most cases recover spontaneously• SURGICAL TREATMENT-explore the nerve and divide the constricting band which is commonly found near the origin of the nerve.
POSTERIOR INTEROSSEUS SYNDROME• Conservative treatment for 4-8 weeks• Refractory cases, surgery is considered which involves exploration and dividing of arcade of Fosche and any other constricting bands.
TARSAL TUNNEL SYNDROME• Open exploration of the TT is the preferred surgical technique• Success rates for surgical decompression of the TT have been reported to be between 44% and 93%,Success defined as resolution or improvement of symptoms, no requirement for pain medications, and the ability to return to work.• The deep fascia over the neurovascular bundle is divided proximal to the Tarsal tunnel(TT), and division is continued distally upto flexor retinaculum..• The medial and lateral plantar nerves are followed into their separate tunnels. Both tunnels are released by dividing the fascial origin of the abductor hallucis brevis, which forms their roof.• Complete external neurolysis is usually performed
MERALGIA PARESTHETICA• Surgical management has 2 options- Decompression of the nerve Sectioning of the nerve• A horizontal or curvilinear vertical incision medial to ASIS is used to locate the nerve.• All possible constricting bands to be divided and free space should be made around the nerve.• Some advocate transposing the nerve medially for a straighter course.
THORACIC OUTLET SYNDROMETYPES1. Anterior supraclavicular approach-most commonly used.Wider exposure of the supraclavicular plexus and the middle two thirds of the first rib, where most potential anomalous fibrous bands are attached.2. Transaxillary approach with first rib resection- Advantage is, it allows easy and almost complete access to the first rib, unhindered by adjacent neurovascular structures3. Posterior subscapular approach-excellent exposure of the C8 and T1 spinal nerves and the lower trunk of the brachial plexus. Useful in patients who have previously undergone anterior approaches or received radiation therapy to the area.
COMMON PERONEAL NERVE ENTRAPMENT• Surgical decompression of the nerve• Excision of the offending lesion E.g., intra neural or extra neural tumors or masses.• Open decompression is recommended between third and fourth months if symptoms persist or recovery is incomplete, even if the patient has only sensory symptoms that have been substantiated by electro physiologic studies.• Surgery involves exposure of the nerve, decompression by releasing the tendinous arch and other bands if present and reconstruction in severely damaged cases.
RADIAL TUNNEL SYNDROMECONTRAVERSIES• There is considerable doubts as to whether this clinical entity or anatomical tunnel exists• It is differentiated from PIN syndrome(which involves loss of motor function ) by presence of pain and tenderness over proximal radial forearm without weakness. Recent studies have shown that patients diagnosed clinically and electro physiologically as Radial tunnel syndrome had MRI T2 and STIR hyper intense signal changes in the muscles innervated by PIN, indicating its involvement• ENMG is usually normal• The duration of recommended conservative management in cases with or without weakness has wide variation among different studies. There is no study comparing non surgical treatment with the surgery treatment.• Effectiveness of the surgical decompression of the PIN was found to be in the range of 67% to 95% in different studies.
PIRIFORMIS SYNDROMECONTRAVERSIES/CONFUSIONS• Gluteal trauma with hematoma, injection palsy, compression, hip arthroplasty, hip fracture, or endometrial Implant can cause proximal sciatic nerve compression near to piriformis and hence need to be differentiated before labelling proximal sciatic nerve compression as piriformis syndrome• How much a small structure like piriformis muscle can compress the sciatic nerve is very doubtful.• SPASM-Abnormal leg movement(external rotation ) is never described, So is spasm isometric ? Nerve compression?• The PS is the only entrapment neuropathy attributable to a muscle.• Pace test –sciatic pain with abduction of the hip against resistance. Freiburg test- pain with forced internal rotation, stretching the muscle. Diametrically opposite tests causing same compression?• Freiburg test should decompress the nerve by stretching the muscle, removing the pressure and improving the symptoms.
THORACIC OUTLET SYNDROMECONTROVERSIES• The most common variety is the disputed neurogenic one making upto 97% of TOS• The diagnostic tests are exceptionally sensitive and have poor specificity.• The provocative tests have been found to be abnormal in control groups to the extent of 2/3rd in RCTs• In proximal entrapments the role of electrophysiology is limited as distal recording will be normal and localisation is difficult(even in true thoracic syndromes).• The diagnosis of disputed TOS is by clinical signs and symptoms as elctrophysiology doesn’t show any abnormality.• On MRI nerve compression has been found in only few about 7% of symptomatic patients.• Patients with disputed type undergoing surgery can develop objective deficits which were absent before. Roos DB. Thoracic outlet syndrome is underdiagnosed.Muscle Nerve 1999;22:126–9 [discussion 136–7]
OUTCOME OF SURGICAL TREATMENTOutcome is good in well recognized and common entrapmentslike Carpal tunnel syndrome:• Open method-improvement in pain-87%,paresthesias-92%• Endoscopy- upto 82% patients had complete resolution of symptoms (Hankins et al)• In controversial syndromes like Thoracic outlet syndrome- Resolution of pain or paresthesias, or both is seen in 50% to 60% of patients and a partial response in another 20% to 30%.• Hankins CL, Brown MG, Lopez RA, et al. A 12-year experience using the Brown two-portal endoscopic procedure of transverse carpal ligament release in 14,722 patients: defining a new paradigm in the treatment of carpal tunnel syndrome. Plast Reconstr Surg. 2007;120:1911.• Maxey TS, Reece TB, Ellman PI, et al. Safety and efficacy of the supraclavicular approach to thoracic outlet decompression. Ann Thorac Surg. 2003;76:396.
COMPLICATIONSComplications are few:GeneralScarring, operative site pain and pain with movement, injury to cutaneous nervesand paresthesia, injury to adjacent neurovascular structures, neuroma formation• Approach related deficits like weakness due to muscle dissection, fascial cutting• Requirement for re-explorationSpecific complicationsChylothorax, pneumothorax, phrenic nerve injury,supraclavicular numbness inThoracic outlet syndrome surgeries• Hernia formation due to inguinal ligament cutting in treatment of meralgia paresthetica• Carpal tunnel release surgeries-Incomplete sectioning of the TCL is the most common complication . Injury to the palmar cutaneous branch (PCB) of the median nerve is the second most common complication. Severance of the thenar motor branch (TMB) of the median nerve
SURGICAL OUTCOME OF ULNAR NERVE LESIONS AT ELBOW.• Patients with ulnar nerve injuries who underwent secondary nerve repair had improvement in 64.7% cases.• Best results when done within 6 months of trauma. Dr.Gopalakrishnan MS,Dissertation for MCh in neurosurgery,NIMHANS 2005.
AN ASSESSMENT OF REGENERATION IN RAT SCIATIC NERVE• Uptake of pretreated (cold preserved) allografts better with primary suturing. Dr.Shaji KR ,Dissertation for MCh in Neurosurgery, NIMHANS 2000.
PERIPHERAL NERVE REGENERATION ACROSS COLD PRESERVED NERVE ALLOGRAFTS IN RATS .• Cold preservation reduces host immune response to allograft.• Co-relation noted between functional, electrophysiological and histological outcome in rats.• Laminin has an important role in nerve regeneration Dr.Dhananjay I Bhat, Dissertation for MCh in Neurosurgery, NIMHANS 2003.
BRACHIAL PLEXUS INJURIES -OUTCOME FOLLOWING NEUROTIZATION• Intercostal nerve neurotization for Brachial plexus (avulsions) is a viable option.• Results with Axillary nerve neurotization better than musculocutaneous nerve.• Good functional outcome if done within 6 months of denervation (Early diagnosis important) Dr.Aliasgar Moiyadi, Dissertation for MCh Neurosurgery,NIMHANS 2005. J Neurosurg 107:308-313, 2007
TO SUMMARISE• Entrapment neuropathies are far more common than thought to be• These syndromes are under-diagnosed• With advances in investigations like MRI more cases can be diagnosed and less controversies in decision regarding management• Conservative management initially• Surgery for appropiate patients• Response to surgery is good overall• Most of these entrapments can be relieved under local anasthesia on daycare bases with good results• Complications can be reduced by better anatomical knowledge