Postoperative Muscle Weakness Research Articles

Lambert-Eaton myasthenic syndrome as a cause of persistent neuromuscular weakness after a mediastinoscopic biopsy -A case report-

There are many causes of prolonged postoperative muscle weakness, including drugs, residual anesthetics, cerebrovascular events, electrolyte imbalance, hypothermia, and neuromuscular disease. Neuromuscular diseases are relatively rare, with the most common being myasthenia gravis and Lambert-Eaton myasthenic syndrome (LEMS). We report an unusual case in which a patient who was given a muscle relaxant during mediastinoscopy developed postoperative muscle weakness that was ultimately diagnosed as secondary to LEMS.

Postoperative muscle weakness in a patient recently treated with infliximab

We present a case of profound postoperative muscle weakness in a patient who had been treated with infliximab, and whose weakness had not manifested pre-operatively. We believe this to be the first case report of infliximab-related muscle weakness manifesting immediately after anaesthesia.

Sugammadex: Another Milestone in Clinical Neuromuscular Pharmacology

Sugammadex is a revolutionary investigational reversal drug currently undergoing Phase III testing whose introduction into clinical practice may change the face of clinical neuromuscular pharmacology. A modified gamma-cyclodextrin, sugammadex exerts its effect by forming very tight water-soluble complexes at a 1:1 ratio with steroidal neuromuscular blocking drugs (rocuronium > vecuronium >> pancuronium). During rocuronium-induced neuromuscular blockade, the IV administration of sugammadex creates a concentration gradient favoring the movement of rocuronium molecules from the neuromuscular junction back into the plasma, which results in a fast recovery of neuromuscular function. Sugammadex is biologically inactive, does not bind to plasma proteins, and appears to be safe and well tolerated. Additionally, it has no effect on acetylcholinesterase or any receptor system in the body. The compound's efficacy as an antagonist does not appear to rely on renal excretion of the cyclodextrin-relaxant complex. Human and animal studies have demonstrated that sugammadex can reverse very deep neuromuscular blockade induced by rocuronium without muscle weakness. Its future clinical use should decrease the incidence of postoperative muscle weakness, and thus contribute to increased patient safety. Sugammadex will also facilitate the use of rocuronium for rapid sequence induction of anesthesia by providing a faster onset-offset profile than that seen with 1.0 mg/kg succinylcholine. Furthermore, no additional anticholinesterase or anticholinergic drugs would be needed for antagonism of residual neuromuscular blockade, which would mean the end of the cardiovascular and other side effects of these compounds. The clinical use of sugammadex promises to eliminate many of the shortcomings in our current practice with regard to the antagonism of rocuronium and possibly other steroidal neuromuscular blockers.

Posterior Osteotomy and Instrumentation for Thoracolumbar Kyphosis in Patients With Achondroplasia

A retrospective case series of surgically treated achondroplastic patients with severe thoracolumbar kyphosis. To evaluate the outcome of surgical treatment for thoracolumbar kyphosis in patients associated with achondroplasia presenting with paraparesis. Thoracolumbar kyphosis is one of the frequent skeletal manifestations in patients with achondroplasia. Few papers have been published on the surgical treatment of this condition, especially in skeletally mature patients. Four patients with achondroplasia who developed neurologic deficit due to severe thoracolumbar kyphosis and underwent surgical treatment were evaluated (mean age, 32.5 years; mean follow-up, 3.0 years). Posterior osteotomy with segmental instrumentation was performed in all cases. The surgical procedures included pedicle subtraction osteotomy in 2 patients without a hypoplastic apical vertebra and spondylectomy with reconstruction of the anterior column in 2 patients with a hypoplastic apical vertebra. Neurologic outcomes (JOA scores), correction of kyphosis, and operative complications were assessed. All patients had gait disturbance, and 2 patients were unambulatory before surgery. The average preoperative JOA score was 5.8 points, which was improved to 9.3 points at the final follow-up (mean recovery rate, 75%). All patients obtained neurologic improvement and became ambulatory either with or without crutches after surgery. The mean preoperative kyphotic angle was 96.3 degrees (range, 57 degrees -117 degrees ). The postoperative angles averaged 55.3 degrees (range, 30 degrees -110 degrees ), yielding a mean correction rate of 43.6%. Neither loss of correction nor pseudarthrosis has been observed during the follow-up period. Partial nerve root laceration and dural tear resulting in transient postoperative muscle weakness were observed in 2 patients as complications. Posterior spinal osteotomy with segmental instrumentation is a reasonable surgical option for thoracolumbar kyphosis in patients with achondroplasia. Modification of the surgical procedures depending on the presence or absence of the dysplastic changes of the apical vertebra is necessary to obtain optimal results.

Patient Outcomes After Axillary Lymph Node Dissection for Breast Cancer: Use of Postoperative Continuous Local Anesthesia Infusion

Although considered a safe surgical procedure, axillary lymph node dissection (ALND) is associated with postoperative numbness, paresthesias, pain, and muscle weakness. Despite meticulous surgical technique and the absence of long thoracic or thoracodorsal nerve injury, the risk of these complications are reported as great as 35% to 50%, with a subset of patients developing chronic pain syndromes. Female patients (n = 27) undergoing Level I-II ALND for breast cancer were recruited. After ALND, patients were randomized to three groups. Group 1 received standard axillary lymph node dissection. Patients assigned to group 2 or 3 (double-blinded) received 120 h continuous 0.9% saline solution or 0.5% bupivacaine using a catheter placed into the axilla and delivered by an elastomeric pump device. After routine postoperative care, patients were discharged with oral opioid analgesics. Twice-daily assessment of pain, sedation, and nausea were conducted using validated visual-analog scale measures. Daily and total opioid analgesic requirements after surgery were recorded. Patients treated with a continuous infusion of bupivacaine experienced significantly lower pain scores (P < 0.001) during the first 5 postoperative days. Postoperative opioid analgesic requirements also were significantly decreased in the bupivacaine group, and these effects persisted until postoperative day 14 (P < 0.001). Concomitant to the observed decreases in pain and oral opioid requirements, nausea and morning sedation also were significantly reduced. There were no pump-related complications, wound infections, or postoperative axillary fluid collections. The use of continuous administration of bupivicaine after ALND significantly decreases pain and opioid analgesic requirements, with concomitant decreases in nausea and sedation. This study provides encouraging evidence of the therapeutic benefits of continuous infusion of local anesthesia and may represent a valuable adjunct for surgical patients who require ALND, including those with breast cancer and melanoma.

Nerve root distribution of deltoid and biceps brachii muscle in cervical spondylotic myelopathy: a potential risk factor for postoperative shoulder muscle weakness after posterior decompression

To investigate the nerve root distribution of deltoid and biceps brachii muscle, compound muscle action potentials (CMAPs) were recorded intraoperatively following nerve root stimulation in cervical spondylotic myelopathy. A total of 19 upper limbs in 12 patients aged 55–72 years (mean, 65.5 years) with cervical spondylotic myelopathy were examined. CMAPs were recorded from deltoid and biceps brachii muscle following C5 and C6 root stimulation. Although both C5 and C6 roots were innervated for deltoid and biceps brachii muscle in all subjects, the amplitude ratio of CMAPs (C5/C6) differed individually depending on the symptomatic intervertebral levels of the spinal cord. The C5 root predominantly innervated both deltoid and biceps brachii in patients with symptomatic cord lesions at the C4–C5 intervertebral level compared to patients with symptomatic cord lesions at the C5–C6 intervertebral level. Although no patients sustained postoperative radiculopathy in our study, severe weakness and unfavorable recovery are expected when the C5 root in patients with C4–C5 myelopathy is damaged. From the electrophysiological aspect, C4–C5 cord lesions are likely to be a potential risk factor for postoperative shoulder muscle weakness in patients with compressive cervical myelopathy.

Patient analgesia after axillary lymph node dissection (ALND): outcomes in pain management using long-term continuous local anesthesia delivery

Background: Although considered a safe surgical procedure, ALND is associated with post-operative numbness, paresthesias, pain, and muscle weakness. Despite meticulous surgical technique, and absent evidence of long thoracic or thoracodorsal nerve injury, the risk of these complications have been reported as 35–50%, with a subset of patients developing chronic pain. Methods: Female patients (n = 25) undergoing Level I–II ALND for breast cancer were recruited. After ALND, patients were randomized to three groups. Group #1 received no pump or infusion. Patients assigned to group #2–#3 (double-blinded) received 120 hours continuous bupivacaine (BPV) or saline infusion using an On-Q pump (I-Flow Corporation) via an axillary catheter. Patients were discharged with oral opioid analgesics and performed twice-daily assessment of pain, sedation, and nausea using validated visual-analog scale measures. Daily opioid analgesic requirements were recorded. Results: Patients treated with bupivacaine experienced statistically-significant lower pain scores (p < 0.002) during the first five post-operative days. Post-operative sedation and nausea scores and opioid analgesic requirements were significantly decreased in the bupivacaine group, and these effects persisted until post-operative day 14 (p < 0.001, p < 0.04, and p < 0.00001 respectively). Data are summarized in Table I. TABLE—ABSTRACT 14MeasureControl (n = 8)BPV (n = 8)Saline (n = 9)Morning Pain Score29.77.621.54p = 0.001Evening Pain Score30.17.019.0p =0.0002Morning Sedation Score19.34.416.0p < 0.001Evening Sedation Score18.67.010.0p < 0.001Morning Nausea Score6.81.57.4p = 0.039Evening Nausea Score6.31.65.2pP = 0.015Oral Opioid Analgesics122.622.052.0p < 0.00001POD: Post-operative day 1–14, Score: Visual Analog Scale (0–100); Opioid Analgesics (total mg) There were no complications. Conclusions: Use of continuous administration of axillary local anesthesia significantly decreases pain, sedation, and opioid analgesic requirements following ALND. This pilot study is encouraging, warranting further evaluation of this treatment modality to determine its potential impact upon long-term complications following ALND.

Residual neuromuscular blockade in the immediate postoperative period

Neuromuscular blocking agents are among the most potent and dangerous drugs administered in the course of a general anesthetic. Their residual actions can have profound effects on a patient's ability to adequately ventilate. Understanding the basics of their actions and the methods of monitoring the level of neuromuscular blockade will assist the PACU nurse in diagnosing the cause of postoperative muscle weakness and hypoventilation. This article will review the mechanisms of action and monitoring of neuromuscular blocking agents, as well as provide a basic overview of postoperative complications involving hypoventilation and motor weakness. © 2002 by American Society of PeriAnesthesia Nurses.

A retrospective comparison of abdominal muscle strength following breast reconstruction with a free TRAM or DIEP flap

Abdominal weakness is a known potential complication of breast reconstruction with a pedicled or free TRAM flap. It has been presumed that the DIEP flap, which involves no muscle resection, does not compromise abdominal muscle strength but little objective research exists to substantiate this. The aims of this retrospective study were to compare abdominal muscle strength following free TRAM flap and DIEP flap, to compare both groups with a control group and to establish the effect of both procedures on functional activities. Fifty women (23 with a DIEP flap, 27 with a free TRAM flap) plus 32 non-operated controls underwent assessment of their abdominal and back extensor muscle strength on a KIN COM isokinetic dynamometer. Two questionnaires were used to establish the impact on function. The TRAM flap group had significant weakness of the abdominal and back extensor muscles compared with the DIEP flap group and the control group. The trend was for the DIEP flap group to have weaker abdominal muscles than the control group. There was a higher level of abdominal pain and a greater number of reported functional difficulties in the TRAM flap group than in the DIEP flap group. This study demonstrates that whilst the DIEP flap can reduce the strength deficit caused by the free TRAM flap, abdominal weakness can still result from the DIEP flap. A randomised controlled trial is currently underway to investigate the effect of preoperative abdominal exercises in preventing/minimising postoperative abdominal muscle weakness in this group.

Surgical treatment of comminuted fractures of the distal clavicle using Wolter clavicular plates.

Surgical reduction and fixation using Wolter clavicular plates was performed in 16 patients with distal clavicle fractures. Good bony union was obtained in all cases. The patients had neither postoperative pain nor muscle weakness. Compared with tension band wiring, the Wolter clavicular plates were better able to maintain the anatomic repositioning of comminuted distal clavicle fractures. However this method takes longer and requires a second operation for plate removal. Wolter clavicular plate placement is the treatment of choice for unstable distal clavicle fractures with small comminuted fragments.

Postoperative Neuromuscular Function in Pediatric Day-care Patients

After anesthesia employing nondepolarizing muscle relaxants, 30%-40% of adult patients demonstrate residual paralysis with a train-of-four ratio less than 70%, but it is not known if the same is true for children. This study was designed to investigate neuromuscular transmission in 91 ASA physical status I or II day-care children (aged 0-10 yr) after halothane anesthesia in which pancuronium (n = 34), atracurium (n = 32), or vecuronium (n = 25) was administered. Peripheral nerve stimulation was used clinically to assess neuromuscular blockade during surgery. In the recovery room, the evoked response of the adductor pollicis muscle was measured by train-of-four stimulation of the ulnar nerve. This measurement was made (mean +/- SEM) at 18.0 +/- 1.5, 15.0 +/- 1.3, and 15.0 +/- 1.7 min after pharmacologic antagonism with 0.02 mg/kg atropine and 0.06 mg/kg neostigmine in the pancuronium, atracurium, and vecuronium groups, respectively. There were no differences in the ages of the patients in the three groups at 4.3 +/- 0.4, 4.0 +/- 0.4, and 5.0 +/- 0.5 yr, with 17 children less than 2 yr. Recovery from neuromuscular blockade in all three groups was almost complete. The train-of-four ratio (height of fourth twitch compared with the first) was similar in patients who had received pancuronium (96.7% +/- 0.9%), atracurium (95.5% +/- 0.9%), or vecuronium (96.3% +/- 1.3%). Therefore, postoperative muscle weakness or respiratory impairment is unlikely in pediatric day-care surgical patients more than 2 yr old when these anesthetic techniques are used.

Isoflurane for Thymectomy in Myasthenia Gravis

The clinical and electromyographic effects of isoflurane were studied in eight myasthenic patients undergoing trans-sternal thymectomy. After inhalational induction of anaesthesia, intubating and operating conditions were good. Recovery from anaesthesia was rapid with minimal postoperative residual muscle weakness or respiratory depression. All patients were extubated within the first postoperative hour. Integrated electromyographic monitoring of the train-of-four response of adductor pollicis demonstrated that myasthenics are more sensitive than nonmyasthenics to the neuromuscular depressant effects of isoflurane. Recovery of the integrated electromyographic response was incomplete despite a satisfactory clinical recovery.