Feasibility of Nerve Stimulator as a Supplemental Aid for Lumbar Transforaminal Epidural Block

Background

The purpose of this study was to evaluate the clinical feasibility of an electric nerve stimulator in a lumbar transforaminal epidural block.

Methods

Using an electric nerve stimulator, transforaminal epidural blocks were performed in 105 segments of 49 patients who presented with lower back pain with radiating pain to lower extremities. The contrast medium was injected to delineate the nerve root after positioning an insulated needle at the intervertebral foramen under fluoroscopic guidance. Then, the nerve root was electrically stimulated with the insulated needle to confirm whether or not the same radiating pain was evoked.

Results

Of the 105 foraminal segments, the same radiating pain was evoked at 0.5 mAh in 47 segments (44.8%), at 1.0 mAh in 22 (21.0%), at 1.5 mAh in 3 (2.9%), at 2.0 mAh in 15 (14.3%), at 2.5 mAh in 4 (3.8%), and at 3.0 mAh in 5 (4.8%). No response was observed in 9 segments (8.6%). The fluoroscopy revealed successful positioning of the needle in the patients with an evoked radiating pain over 2.0 mAh. The visual analogue scale (VAS) obtained for pain improved from a mean of 7.5 to 2.7 after the block (p = 0.001). In the 9 cases without response to electrical stimulation, the patients showed an improvement on VAS from 7.8 to 3.4 (p= 0.008) also.

Conclusions

A nerve stimulator can help to predict the accuracy of needle positioning as a supplemental aid for a successful lumbar transforaminal epidural block. It is sufficient to initiate a proper stimulation amplitude of the nerve at 2 mAh.     

Prediction of Facial Nerve Function After Surgery for Cerebellopontine Angle Tumors: Use of a Facial Nerve Stimulator and Monitor

A series of 18 patients undergoing surgery for cerebellopontine angle tumors is reported. Patients were grouped according to size of tumor (0 to 2.5 cm, 11 cases; more than 2.5 cm, 7 cases). In all, the facial nerve was identified and conductance assessed by monitoring the facial electromyographic response to facial nerve stimulation. Postoperative facial nerve function was graded clinically after 3 months according to the House scale. Tumor removal was complete in all cases. In patients with tumors up to 2.5 cm the facial nerve was intact to visual inspection at the end of the procedure in all but one, where partial division was evident. In this group intraoperative facial nerve stimulation indicated electrical integrity in 8 of the 11 cases, all of which regained good facial nerve function postoperatively (House grades I and II). Nerve conduction was lost during the operation in the remaining three patients with small tumors; two subsequently developed a moderately severe (grade IV) dysfunction and the third, a total paralysis (grade VI). In the large (more than 2.5 cm) tumor group the facial nerve was anatomically intact in five of the seven cases, partially divided in one, and completely sectioned in the remaining case. Facial nerve stimulation indicated functional integrity in three patients, two of whom developed moderate (grade III) and the third a severe (grade V) dysfunction. In the other four cases nerve function could not be detected at operation; three of these developed a moderate facial nerve dysfunction (grade III/IV) and the final case a complete paralysis (grade VI). Intraoperative facial nerve monitoring appeared to predict eventual facial function accurately in the small tumor group, but did not predict facial nerve recovery reliably following surgery for larger tumors.     

Development of a Novel Detachable Magnetic Nerve Stimulator for Intraoperative Neuromonitoring

Background

Recurrent laryngeal nerve (RLN) palsy is a serious complication of thyroid surgery. During intraoperative neuromonitoring (IONM) of the RLN in thyroid surgery, repeated shifting between surgical instruments and the nerve stimulator is cumbersome and time-consuming. Therefore, we developed a simple detachable magnetic nerve stimulator that may be connected to all metallic surgical instruments. This study aimed to investigate the feasibility and efficacy of this detachable magnetic nerve stimulator for IONM in a porcine model and humans.

Methods

Eight RLNs in four pigs and thirteen in nine patients that underwent thyroidectomy were examined. We developed a detachable nerve stimulator that combined surgical instruments with the nerve-stimulating probe. We evaluated the electromyography (EMG) amplitudes of the RLNs in pigs and patients using conventional nerve probes and surgical instruments with the novel detachable magnetic nerve stimulator attached.

Results

The EMG amplitudes of the eight RLNs in pigs and thirteen in patients were analyzed. The detachable magnetic nerve stimulator was feasible and safe. There was no significant difference in the EMG amplitude between instruments (P = 0.423 in animals, P = 0.446 in humans).

Conclusions

The application of stimulating dissection using a detachable magnetic nerve stimulator during thyroidectomy with IONM is simple, convenient, and effective. It provides surgeons with real-time feedback of the EMG response during intermittent IONM. We propose that this novel device could be an essential guide for most surgeons, especially for less experienced head and neck surgeons.

     

人体膈神经与副膈神经的组织化学研究

研究人体膈神经与副膈神经的运动纤维数量及有髓纤维截面积。方法：运用Ｋａｍｏｖｓｋｙ－Ｒｏｏｔｓ［１］乙酰胆碱酯酶组织化学方法，研究１２例成人膈神经及并存的５例副膈神经。对轴索内酶活性反应呈阳性的纤维，进行计数及纤维截面积图象分析。结果：膈神经与副膈神经绝大部分有髓纤维酶反应呈阳性，所含阳性有膈纤维分别为２６８６根、６３４根。膈神经与副膈神经并存时有髓纤维总数达３２１８根。有髓纤维截面积分别为１０３．８μｍ２、９４．７μｍ２。结论：膈神经含２６８６根运动纤维，有髓纤维截面积为１０３．８μｍ２，是良好的移位动力神经；副膈神经与其并存，有重要的临床意义。     

Surgical Options for Complete Resectable Lung Cancer Invading the Phrenic Nerve

We describe a 58-year-old male diagnosed with a tumour of the left lung, which on subsequent thoracotomy proved to be invading the phrenic nerve. The clinical and spirometric outcome of a lobectomy, which resulted in a postoperative ipsilateral hemidiaphragmatic paralysis, versus the alternative surgical option of a pneumonectomy is discussed.     

Suprascapular Nerve Block for Shoulder Arthroscopy

The suprascapular nerve (SSN) originates from the C5 and C6 nerve roots and provides sensation for the posterior shoulder capsule, acromioclavicular joint, subacromial bursa, and coracoclavicular ligament. Blocking it provides pre-emptive anesthesia, decreased intraoperative pain, and postoperative pain relief in shoulder arthroscopy. Under general anesthesia, 25 mL of 0.5% bupivacaine is injected by a spinal needle placed 1 cm medial to the convergence of the spine and clavicle, angling toward the coracoid. At a depth of 3 to 4 cm, the needle strikes the scapula body. The surgeon probes with the needle anteriorly until the scapula is no longer felt, then moves the needle back posteriorly until the bone is felt again. This places the needle at the coracoid base in the supraspinatus fossa where the SSN curves around the coracoid and heads to the glenohumeral joint. At this point, the anesthetic is injected, “flooding” the SSN location. In addition to the SSN block, other pain-control procedures should be performed, including bupivacaine injection of all portals and an intra-articular injection of morphine sulfate at the end of the procedure. The SSN block is an effective technique and can reduce postoperative medication needs and allow earlier patient discharge from the surgery center.