Rapid onset of ulnar nerve dysfunction during transient occlusion of the brachial artery

[Potential complications of patient positioning in spine surgery]

Patient position on the operating table during spine surgery is important for optimal intraoperative manipulations. However, this position is far from physiological one. An unnatural position, surgery time and sometimes necessary intraoperative change in body position can lead to certain neurological and somatic complications. Most of these events can significantly reduce the patient's working capacity and quality of life and even result disability. Medical staff placing the patient on operating table, neurosurgeons and anesthesiologists should be aware of risk factors of similar complications and their prevention. The authors describe the most serious and difficult for correction conditions, such as peripheral neuropathy, damage to visual analyzer, as well as optimal method of patient positioning.

Vibrotactile sense 5 years after carpal tunnel release in people with diabetes: A prospective study with matched controls

AIM

To compare vibrotactile sense, 5 years after carpal tunnel release in people with and without diabetes.

METHODS

Out of 35 people with diabetes and carpal tunnel syndrome, age- and gender-matched with 31 people without diabetes but with idiopathic carpal tunnel syndrome, 27 and 30 people, respectively, participated in this prolonged follow-up. Vibration perception threshold of the index and little finger (median and ulnar nerve, respectively), 5 years after surgery, was measured at seven different frequencies (8, 16, 32, 64, 125, 250 and 500 Hz).

RESULTS

Significant improvement of vibration perception threshold from 1 to 5 years after carpal tunnel release was found at 64 Hz for people with diabetes, while improvement for people without diabetes was demonstrated at several frequencies (64-250 Hz). However, both groups demonstrated a significant decrease in vibration perception threshold for the low frequencies (8-16 Hz). At 5 years, people with diabetes had significantly impaired vibration perception threshold at the index finger for high frequencies (125-500 Hz), and for nearly all frequencies (16 Hz, 64-500 Hz) at the little finger, compared to people without diabetes.

CONCLUSION

After carpal tunnel release, significant mid-term improvement of vibrotactile sense appears limited for people with diabetes, compared to a continuous improvement for people without diabetes. In addition, a decline in low-frequency vibrotactile sense occurs for the median as well as the ulnar nerve innervated fingers. Clinical Trial Registration NCT01201109.

Current and future applications of ultrasound imaging in peripheral nerve disorders

Neuromuscular ultrasound (NMUS) is a rapidly evolving technique used in neuromuscular medicine to provide complimentary information to standard electrodiagnostic studies. NMUS provides a dynamic, real time assessment of anatomy which can alter both diagnostic and management pathways in peripheral nerve disorders. This review describes the current and future techniques used in NMUS and details the applications and developments in the diagnosis and monitoring of compressive, hereditary, immune-mediated and axonal peripheral nerve disorders, and motor neuron diseases. Technological advances have allowed the increased utilisation of ultrasound for management of peripheral nerve disorders; however, several practical considerations need to be taken into account to facilitate the widespread uptake of this technique.

Imaging in the diagnosis of ulnar nerve pathologies-a neoteric approach

The ulnar nerve is a branch of the C8 and T1 nerve roots and arises from the medial cord of the brachial plexus. It supplies the intrinsic muscles of the hand and assists the median nerve in functioning of the flexors. Also known as the musician’s nerve, it is the second most common nerve involved in compressive neuropathy following the median nerve. Common sites of entrapment include cubital tunnel at the elbow, the ulnar groove in the humerus and the Guyon’s canal at the wrist. Patients present with altered sensation in the ulnar fourth and the fifth digit and the medial side of arm with loss of function of intrinsic muscles of the hand, the flexor carpi ulnaris and ulnar fibres of flexor digitorum superficialis in more severe cases. Diagnosis relies on clinical examination, electrodiagnostic studies and imaging findings. Plain radiographs are used to identify fracture sites, callus, or tumours as cause of compression. Technological advances in ultrasonography have allowed direct visualisation of the involved nerve with assessment of exact site, extent and type of injury. It yields unmatched information about anatomical details of the nerve. MR imaging adds to soft tissue details and helps in characterising the lesion. This pictorial review aims to illustrate a wide spectrum of causes of ulnar neuropathies as seen on ultrasound and MRI and emphasises upon the importance of imaging modalities in the diagnosis of neuropathies.

Bilateral position-related ulnar neuropathy at elbow in pediatric population and review of the literature

Perioperative ulnar neuropathies attributed to inappropriate arm positioning and padding during surgical procedures are commonly found in adults. However, their extremely rare incidence in the pediatric population may cause absent awareness of the risk of nerve injury in anesthetized pediatric patients. Furthermore, young patients respond to conservative treatment of neuropathy less favorably than adults and their response also depends on the pathomechanism of the ulnar nerve injury. A surgeon's or anesthetist's failure to recognize all of these specifics in children may result in substantial morbidity of young patients leading to lawsuits. Fortunately, with an adequate knowledge of surgical anatomy and types of procedures and positions in which the ulnar nerve is particularly vulnerable, and familiarity with measures to minimize the potential for neuropathy, this serious complication can be prevented. The aims of this review are to highlight personal experience and current knowledge of the rare position-related ulnar neuropathy, both from a clinical and anatomical-pathophysiological perspective, and to raise awareness about this rare but serious complication in the pediatric population.

Evoked potential monitoring identifies possible neurological injury during positioning for craniotomy

Somatosensory-evoked potential (SSEP) monitoring is commonly used to detect changes in nerve conduction and prevent impending nerve injury. We present a case series of two patients who had SSEP monitoring for their surgical craniotomy procedure, and who, upon positioning supine with their head tilted 30 degrees-45 degrees, developed unilateral upper extremity SSEP changes. These SSEP changes were reversed when the patients were repositioned. These cases indicate the clinical usefulness of monitoring SSEPs while positioning the patient and adjusting position accordingly to prevent injury.

Hereditary neuropathy with liability to pressure palsies and anaesthesia: peri-operative nerve injury

A 43-year-old female with carcinoma of the left breast underwent wide local excision of the tumour and sentinel lymph node biopsy under general anaesthesia. Three lymph nodes were removed uneventfully during the operation. Postoperatively, the patient complained of weakness and decreased sensation of her left arm. A diagnosis of peri-operative neuropraxia was made. This resolved completely over the following 4 weeks. Genetic testing confirmed a diagnosis of hereditary neuropathy with liability to pressure palsies.

A review of perioperative nerve injury to the upper extremities

Perioperative nerve injuries can be a complication of surgical procedures and accounts for approximately 16% of all anesthesia-related claims in the United States. Whereas ulnar neuropathy at the elbow is the most common, other nerve injuries of the upper extremity and the phrenic nerve are not rare occurrences. A number of possible etiologies have been proposed to explain perioperative nerve injury to include stretch, compression, ischemia, and metabolic derangement. There appears to be additional factors making some patients more prone to nerve injury than others, for example, the sex of the patient and pre-existing disease. Also, in some cases there is a discrepancy between the timing of the surgery and the injury manifestations that can be the result of delayed recognition or an insult in the postoperative setting.

Peripheral neuropathy in healthy men volunteers anesthetized with 1.25 MAC sevoflurane for 8 hours

Two men volunteers developed peripheral neuropathy after prolonged anesthesia with 1.25 minimum alveolar concentration sevoflurane at an inflow rate of 2 L/minute of fresh gas that caused concurrent administration of relatively large doses (ppm-hrs) of the degradation product of sevoflurane, compound A. Other similarly treated volunteers had lesser degrees of transient neuropathy. This result does not prove but raises the question of whether compound A or other factors associated with sevoflurane anesthesia can predispose patients to peripheral neuropathy.