Focal Compression Neuropathy

Compression of a peripheral nerve of the extremities (“pinched nerve”)  tends to cause pain, changes in sensation of skin areas innervated by the involved nerve (numbness, pins & needles, anaesthesia) and/or weakness and wasting of target muscles. The focal neuropathies treated most frequently by surgery are carpal tunnel syndrome and cubital tunnel syndrome in the arm, and meralgia paraesthetica in the leg. Less common and somewhat controversial entities include supinator syndrome, thoracic outlet syndrome, tarsal tunnel syndrome, and peroneal nerve entrapment. Diagnosis is by clinical assessment plus electrophysiological studies and /or imaging.

Carpaltunnel Syndrome (CTS) is more common in women than men. The classic symptoms are nocturnal numbess of the fingers with associated pain in the forearm or even the arm. A variant presentation in older persons is painless loss of strength and bulk of thumb muscles and loss of sensation on the radial three digits. The diagnosis is usually confirmed by nerve conduction studies although MRI study of the wrist is being used increasingly frequently. The symptoms of median nerve compression in the carpal tunnel may be alleviated by wrist splints or disappear after birth if they come on during pregnancy. The median nerve at the wrist can be decompressed by conventional or endoscopic surgery. For carpal tunnel syndrome without persistent sensory change, symptoms are almost always relieved immediately with very low morbidity. When there is established sensory loss from median nerve compression at the wrist, recovery of sensation may be prolonged and incomplete although pain should be relieved promptly.

Some intraoperative pictures showing the differences between open and endoscopic carpal tunnel release (click on thumbnails to enlarge):

Offene und endoskopische Dekompression bei CTS

Abb.1 Krishnan-Endoscope Endoskopische CTS-Operation

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Ulnar Neuropathy/ Cubitaltunnel Syndrome (CbTS): If an ulnar neuropathy is of sudden onset after suspected external compression, then surgery is probably not indicated. When the onset is progressive, surgery is usually indicated. The diagnosis is confirmed by nerve conduction studies and/or imaging by MRI scanning or sonography. Relief of symptoms from ulnar nerve decompression at the elbow is less predictable and more delayed than for carpal tunnel syndrome. Several randomised controlled studies have shown that simple decompression of the ulnar nerve at the elbow (which can be performed under local anaesthesia) has fewer complications and is as effective as more invasive procedures involving nerve transposition.

Intraoperative photographs showing open and endscopic operations in CbTS (click on thumbnails to enlarge):

Open Versus Endo CbTS Endoscopic transposition CbTS

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Thoracic-Outlet-Syndrome: TOS leads to the compression oft he brachial plexus and/or the subclavian blood vessels at the level of the shoulder. Women in the age group 25-40 years suffer more often than men  at a ratio of 4:1. During the early stages, the symptoms are mainly tingling and loss of sensation with or without pain with elevation and abduction of the shoulder. This may become more expressed with time and even lead to paralyses of some muscle groups. In the severe case of TOS, patients report of nocturnal pain & numbness, sleep disorder associated with these symptoms, inability to comb or dry their hair (elevate and externally rotate the shoulder) as well as a cold and pale (arterial TOS) or cold and blue (venous TOS) upper extremity. Sometimes a cervical rib or a fibrous band can be found as the cause of the disease, however not always. Approximately 90% of TOS is idiopathic. Approximately 60% of the cases are treated conservatively with postural therapy, muscle relaxing positioning etc. In the extreme, recalcitrant case, surgical intervention is a possibility. Even here, there are several different approaches. The combined approach involves the transaxillary resection of the first rib and any bands and the far lateral cervical approach to resect the stump and/or the cervical rib. This creates more space for the vessels and nerves. If at all surgical treatment is indicated, the above approach is the most optimal and minimally invasive one, in my personal experience, as compared to approaches that require active manipulation of the brachial plexus and vessel structures. Any other approach is reserved for cases of recurrent TOS. Prognosis is generally good, however is also dependent on active physical therapy measures followed directly after the surgical operation

These illsutrations show some pathological factors and diagnoses of TOS and the anatomical rationale of the transaxillary surgical approach (click on thumbnails to enlarge):

TOS-Diagnostics TOS-Symptoms Anat-Surg-TOS MRA-TOS-Pre-Post-OP Pseudarthrosis-TOS clavicle speudrathrosis bone

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Tarsaltunnel Syndrome: Also known as the posterior tarsal tunnel syndrome, the tibial nerve is pinched at the ankle area. The symptoms are pain, paraesthesias and dysaesthesias, weakness or palsy of the foot intrinsic muscles. More often than expected, TTS accompanies diabetes, especially in diabetic foot syndrome. Diagnosis is based on electrophysiological studies and imaging (neurosonography or MRI, which will exclude any cysts or tumours). Surgery is indicated when conservative means of treatment have been unsuccessful. Especially in TTS we tend towards a minimally invasive endoscopic approach we have evolved owing to the frequent wound healing problems seen in this area, especially in diabetics and patients with polyneuropathic conditions.

These illustrations show the endoscopic approach to tarsal tunnel syndrome:

Tarsal Tunnel Syndrom Endoskopie TTS-OP-Setting TTS- Endoscopic steps

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Meralgia paraestetica (burning pain of the anterolateral thigh) results from compression of the lateral femoral cutaneous nerve under the lateral portion of the inguinal ligament. It can be relieved by weight loss and is usually not debilitating enough to warrant surgery. If necessary, the nerve can be decompressed by conventional or endoscopic surgery.

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