Neurological complications after regional anesthesia: contemporary estimates of risk

Use of invasive placebos in research on local anaesthetic interventions

Placebos play a vital role in clinical research, but their invasive use in the context of local anaesthetic blocks is controversial. We assessed whether recently published randomised controlled trials of local anaesthetic blocks risked harming control group patients in contravention of the Declaration of Helsinki. We developed the 'SHAM' (Serious Harm and Morbidity) scale to assess risk: grade 0 = no risk (no intervention); grade 1 = minimal risk (for example, skin allergy to dressing); grade 2 = minor risk (for example, subcutaneous haematoma, infection); grade 3 = moderate risk (with or without placebo injection) (for example, neuropraxia); and grade 4 = major risk (such as blindness, pneumothorax, or liver laceration). Placebo interventions of the 59 included trials were given a SHAM grade. Nine hundred and nineteen patients in 31 studies, including six studies with 183 children, received an invasive placebo assessed as SHAM grade ≥ 3. A high level of agreement (78%, κ = 0.80, p < 0.001) for SHAM grades 0-4 increased to 100% following discussion between assessors. More than half of the randomised controlled study designs subjected patients in control groups to risks of serious or irreversible harm. A debate on whether it is justifiable to expose control group patients to risks of serious harm is overdue.

[Regional anesthesia and neurological diseases]

Modern anesthesia is handling an increasing number of patients with neurological diseases who require narcosis. Regional anesthesia techniques offer qualities which might be advantageous for this group particularly for childbirth. The number of pregnant women with neurological diseases has increased significantly in the recent years due to improved diagnostics and therapy. A more careful approach to regional anesthesia in patients with neurological diseases is necessary as the drugs themselves possess neurotoxic effects and the procedure might worsen the underlying neurological diseases. Additionally, performing regional anesthesia might be more complicated and the resulting blockade might be different from the expected neuronal block. Published data concerning regional anesthesia in this patient group are limited and mainly restricted to case reports. In this review general considerations regarding regional anesthesia, techniques, drugs and methods in these patient groups will be discussed. In the second part the practical approach to regional anesthesia for some of the most important neurological diseases is highlighted.

Continuous infusion versus single bolus popliteal block following major ankle and hindfoot surgery: a prospective, randomized trial

BACKGROUND

Popliteal sciatic nerve blockade is a commonly used technique employed in the management of postoperative pain following foot and ankle surgery. Recent studies have shown that for outpatient surgery, for moderately painful procedures, a continuous infusion of local anesthesia via an in-dwelling catheter for 48 to 72 hours leads to reduced opiate analgesic requirements and improved pain and patient satisfaction scores.

MATERIALS AND METHODS

A prospective, randomized, double blind, placebo-controlled trial of a continuous infusion of bupivacaine verses normal saline via a popliteal catheter after a single bolus popliteal block for 72 hours after major ankle and hind foot surgery was performed in 54 patients.

RESULTS

The average pain scores overall were low (range, 1.1 to 3.6 on a Visual Analogue Scale of 0 to 10) throughout the study period. Statistically significantly lower pain scores with significantly less requirement for supplementary opiate analgesic agents were seen in the treatment group.

CONCLUSION

Despite the statistically significant findings, with such low pain scores in both groups, we believe it remains debatable whether the extra time and cost involved warrants the use of a continuous popliteal blockade over a single bolus injection.

Neurological adverse events following regional anesthesia administration

Regional anesthesia and analgesia have been associated with improved analgesia, decreased postoperative nausea and vomiting, and increased patient satisfaction for many types of surgical procedures. In obstetric anesthesia care, it has also been associated with improved maternal mortality and major morbidity. The majority of neurological adverse events following regional anesthesia administration result in temporary sensory symptoms; long-term or permanent disabling motor and sensory problems are very rare. Infection and hemorrhagic complications, particularly with neuraxial blocks, can cause neurological adverse events. More commonly, however, there are no associated secondary factors and some combination of needle trauma, intraneural injection, and/or local anesthetic toxicity may be associated, but their individual contributions to any event are difficult to define.

Adding regional analgesia to general anaesthesia: increase of risk or improved outcome?

Although it is clear that regional analgesia in association with general anaesthesia substantially reduces postoperative pain, the benefits in terms of overall perioperative outcome are less evident. The aim of this nonsystematic review was to evaluate the effect on middle and long-term postoperative outcomes of adding regional perioperative analgesia to general anaesthesia. This study is based mostly on systematic reviews, large epidemiological studies and large or high-quality randomized controlled trials that were selected and evaluated by the author. The endpoints that are discussed are perioperative morbidity, cancer recurrence, chronic postoperative pain, postoperative rehabilitation and risk of neurologic damage. Epidural analgesia may have a favourable but very small effect on perioperative morbidity. The influence of other regional anaesthetic techniques on perioperative morbidity is unclear. Preliminary data suggest that regional analgesia might reduce the incidence of cancer recurrence. However, adequately powered randomized controlled trials are lacking. The sparse literature available suggests that regional analgesia may prevent the development of chronic postoperative pain. Rehabilitation in the immediate postoperative period is possibly improved, but the advantages in the long term remain unclear. Permanent neurological damage is extremely rare. In conclusion, while the risk of permanent neurologic damage remains extremely low, evidence suggests that regional analgesia may improve relevant outcomes in the long term. The effect size is mostly small or the number-needed-to-treat is high. However, considering the importance of the outcomes of interest, even minor improvement probably has substantial clinical relevance.

Epidural loss-of-resistance biomechanics: an open pilot cadaver study

Purpose

We measured dynamic biomechanics of loss-of-resistance (LOR) epidural placement in prone cadavers, focussing on the period immediately following LOR, to estimate forces acting on the tissue of the epidural space.

Methods

An epidural syringe with 17G Hustead needle was instrumented to track force on the plunger, pressure in the chamber, and movement of barrel and plunger. Insertions were attempted in five formalin-preserved cadavers from T2–3 to L4–5, using LOR with saline or air, and confirmed with X-ray.

Results

Sixteen insertions were successful. Soft tissues in formalin-preserved cadavers are much harder than in living humans. With continuous pressure on the plunger, fluid thrust through the needle at the point of LOR was significantly greater (P = 0.005) with saline (mean ± standard deviation [95% confidence intervals]: 19.3 ± 14.9 [8.3 to 30.3] N); than with air (0.17 ± 0.25 [0 to 0.39] N). Stress exerted on epidural tissue was similar (air = 7792 ± 920 [6986 to 8598] Pa; saline = 7378 ± 3019 [5141 to 9614] Pa); and in both cases was greater than the stress exerted by cerebrospinal fluid pushing outwardly on the dura (4800 Pa).

Conclusion

Formalin-preserved cadavers are too stiff to make them an experimental model from which we can generalize to live humans, although we were successful in entering the epidural space and testing the instrumentation for further studies on live animals or humans. Continuous pressure on the plunger while advancing the epidural needle may “blow” the dura away from the needle tip and help prevent dural puncture. Better results are seen with saline rather than air.

A prospective clinical registry of ultrasound-guided regional anesthesia for ambulatory shoulder surgery

BACKGROUND

There is a lack of clinical registries to document efficacy and safety of ultrasound-guided regional anesthesia. Interscalene blocks are effective for shoulder arthroscopy, and ultrasound guidance may reduce risk. Furthermore, ultrasound-guided supraclavicular block is a novel approach for shoulder anesthesia that may have less risk for neurological symptoms than interscalene block.

METHODS

One thousand one hundred sixty-nine patients undergoing ultrasound-guided regional anesthesia for ambulatory shoulder arthroscopy were enrolled in our prospective registry. Standardized perioperative data were collected including a preoperative neurological screening tool. Either interscalene or supraclavicular block was performed at the discretion of the clinical team. Standardized follow-up was performed in the postanesthesia care unit and at 1 week. Postoperative neurological symptoms (PONS) were assessed at the 1-week follow-up with the same screening tool by a blinded neurologist.

RESULTS

Ultrasound-guided interscalene (n = 515) and supraclavicular (n = 654) blocks had excellent anesthetic success (99.8%; 95% confidence interval [CI], 99.4%-99.9%) with 0% (95% CI, 0%-0.3%) incidence of vascular puncture or intravascular injection. The incidence of hoarseness in the postanesthesia care unit was significantly less with supraclavicular (22% with 95% CI, 19%-26%) than interscalene block (31% with 95% CI, 27%-35%). The incidence of dyspnea was similar (7% for supraclavicular vs 10% with interscalene). No patient had a clinically apparent pneumothorax. The incidence of PONS was very low (0.4% with 95% CI, 0.1%-1%), and there was a 0% (95% CI, 0%-0.3%) incidence of permanent nerve injury.

CONCLUSIONS

Ultrasound-guided interscalene and supraclavicular blocks are effective and safe for shoulder arthroscopy. Temporary and permanent PONS is uncommon.

An evaluation of Thiel-embalmed cadavers for ultrasound-based regional anaesthesia training and research

Working hours of UK trainee doctors have recently been reduced to 48 hours per week, reducing exposure to clinical cases. As such, there is widespread acceptance that trainees need to train in environments other than the ward or operating theatre in order to gain practical skills. Formalin-fixed cadavers demonstrate gross muscle and nerve anatomy but needle insertion under ultrasound guidance is poor. In contrast, a new development in medical simulation is the use of Thiel-embalmed cadavers, developed by Professor Thiel of the University of Graz, Austria, using a novel preservation technique that retains full flexibility of the limbs. Thiel cadavers have been used to successfully simulate laparoscopic surgery, neurosurgery and oral surgery. This paper investigates, for the first time, the application of ultrasound-based regional anaesthesia to the Thiel cadaver by tracing the course of peripheral nerves, injecting local anaesthetic around nerves, and reproducing inadvertent intraneural injection by injecting preservative directly into the nerve. The Thiel cadaver provides good conditions for anaesthetists to simulate regional anaesthetic block techniques using ultrasound.

[Continuous paravertebral block as an analgesic method in thoracotomy]

INTRODUCTION

Open thoracotomy is one of the surgical procedures that is still very painful in the postoperative period, which, in this type of surgery can have on respiratory function and subsequent recovery of the patient.

PATIENTS AND METHOD

The aim of the study is to assess continuous paravertebral thoracic block as an analgesic technique in thoracotomy. A total of 139 patients undergoing pulmonary resection surgery by posterolateral thoracotomy received postoperative analgesia using a 1.5% lidocaine infusion (7-10 ml/h) through a thoracic paravertebral catheter for at least 48 h. Pain intensity measured on the visual analogue scale (VAS) both at rest (passive VAS) and during stimulated cough (active VAS) was recorded at time of discharge from the Recovery Unit, and on the second, third and fourth day post-surgery. Postoperative complications and the need for analgesic rescue were studied.

RESULTS

On discharge from recovery, 98.6% of the patients had mild pain (passive VAS <3), 1.4% had moderate pain (passive VAS 4-6) and none with severe pain (EVA >6); on the 2nd day post-surgery, 97.9% had mild pain, and 1.2% moderate pain; on the third day 98.6% had mild pain and 0.7% moderate pain; and on the 4th day 100% had mild pain. There were no complications arising from the analgesic technique.

CONCLUSIONS

Continuous thoracic paravertebral analgesia is effective and safe in controlling post-thoracotomy pain.

Peripheral neuropathy masquerading as an epidural complication

BACKGROUND

Epidural anaesthesia generally provides safe postoperative pain control, but does carry a small risk of nerve damage.

CASE DESCRIPTION

A 30-year-old woman with long standing rheumatoid arthritis underwent a primary total knee replacement under general anaesthetic. Postoperatively, a continuous epidural infusion was used for pain relief. On discontinuation of the epidural, she was confirmed to have a foot drop. Her subsequent investigation and management for neuropathic pain was coordinated by the acute pain service. Magnetic resonance imaging excluded a central lesion. Nerve conduction studies 6 weeks later confirmed peripheral nerve lesions. The patient's neurological deficit was not due to her epidural, but rather her intraoperative tourniquet.

DISCUSSION

The episode raises a number of discussion points for our pain service around the use of epidurals for knee replacement surgery, the management of nerve injury and the ease at which the epidural can be blamed for coincident injuries. International evidence would suggest that neurological complications following knee replacement are more likely to be related to surgery can epidural analgesia.

Postoperative pain management in the elderly undergoing thoracic surgery

The management of postoperative pain in the elderly represents a considerable challenge because these patients are generally at higher risk for postoperative complications. There are several analgesic options, some of which may influence perioperative morbidity in this high-risk group of patients. Although use of regional analgesia, particularly epidural analgesia is associated with some benefits, including a decrease in perioperative morbidity, there are side effects and complications (eg, medication-related side effects, epidural hematoma, infection) from these and other techniques, and the clinician should evaluate the benefits and risks of each technique on an individual basis. Nevertheless, the available data suggest that use of regional analgesic techniques (ie, epidural and paravertebral catheters) is associated with a decrease in perioperative pulmonary complications.

Evidence and consensus-based German guidelines for the management of analgesia, sedation and delirium in intensive care--short version

Targeted monitoring of analgesia, sedation and delirium, as well as their appropriate management in critically ill patients is a standard of care in intensive care medicine. With the undisputed advantages of goal-oriented therapy established, there was a need to develop our own guidelines on analgesia and sedation in intensive care in Germany and these were published as 2(nd) Generation Guidelines in 2005. Through the dissemination of these guidelines in 2006, use of monitoring was shown to have improved from 8 to 51% and the use of protocol-based approaches increased to 46% (from 21%). Between 2006-2009, the existing guidelines from the DGAI (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin) and DIVI (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin) were developed into 3(rd) Generation Guidelines for the securing and optimization of quality of analgesia, sedation and delirium management in the intensive care unit (ICU). In collaboration with another 10 professional societies, the literature has been reviewed using the criteria of the Oxford Center of Evidence Based Medicine. Using data from 671 reference works, text, diagrams and recommendations were drawn up. In the recommendations, Grade "A" (very strong recommendation), Grade "B" (strong recommendation) and Grade "0" (open recommendation) were agreed. As a result of this process we now have an interdisciplinary and consensus-based set of 3(rd) Generation Guidelines that take into account all critically illness patient populations. The use of protocols for analgesia, sedation and treatment of delirium are repeatedly demonstrated. These guidelines offer treatment recommendations for the ICU team. The implementation of scores and protocols into routine ICU practice is necessary for their success.

Sciatic nerve blockade: a survey of orthopaedic foot and ankle specialists in North America and the United Kingdom

BACKGROUND

Sciatic nerve blocks are used to reduce post-operative pain and allow early discharge for patients undergoing foot and ankle surgery. This study aimed to identify the utilization of this procedure in the US and UK and to establish the standard of care with respect to the level of anesthesia that the patient is under and use of ultrasound localization when performing sciatic nerve blocks.

MATERIALS AND METHODS

A survey of current committee members of AOFAS and members of BOFAS.

RESULTS

Two hundred sixty-three surgeons were contacted with a response rate of 44%. Eighty-two percent commonly used a sciatic nerve blockade. Sixty-nine percent never or only sometimes used ultrasonography and variable levels of nerve stimulation were used. Forty-two percent where happy to have the block performed under full anesthesia. There were significant differences between British and American practices regarding the level of nerve stimulation and the level of anesthesia used. The most common complication cited was prolonged anesthesia of which the vast majority spontaneously resolved. Performing blocks awake or sedated did not seem to alter number of complications seen.

CONCLUSION

This study represents a current practice review of sciatic nerve blocks performed amongst senior foot and ankle surgeons. Although no absolute consensus has been reached as to the use of ultrasound or whether the patient needs to be awake for the procedure, it is clear that the standard of care does not mandate either of these. The differences between US and UK practice are probably cultural and do not appear to affect the number of complications encountered.

Ultrasound and nerve stimulation-guided L5 nerve root block

STUDY DESIGN

Case series.

OBJECTIVE

Evaluation of ultrasound and nerve stimulation-guided L5 nerve root block technique.

SUMMARY OF BACKGROUND DATA

Ultrasound-guided peripheral nerve block has become clinically applied. However, selective lumbosacral nerve root block is conducted under radiographic guidance, which involves patients and operators being exposed to radiation. In addition, it cannot be carried out easily during outpatient visits or at the bedside. We conducted L5 nerve root block, which is one of the most common lumbosacral nerve root block under ultrasonic guidance, using electrical nerve stimulation.

METHODS

We assessed the effectiveness of ultrasound and nerve stimulation-guided L5 nerve root block on 78 patients with L5 radicular syndrome. To compare ultrasonic guidance using electrical nerve stimulation with radiographic guidance, we used a contrast agent and assessed its distribution.

RESULTS

After nerve block, decreased sensation at L5 neural region and diminished/fully resolved pain was observed in all patients except for 3 in whom nerve block could not be conducted as their articular process protruded laterally. Concerning the response to stimulation, all except for these 3 felt the tapping sensation at their L5 neural regions, but no contraction of muscles was observed. The number of patients who showed an extraneural, paraneural, and intraneural pattern on contrast radiography was 71, 4, and 0, respectively.

CONCLUSION

Ultrasound-guided L5 nerve root block using electrical nerve stimulation is a safe and effective method.

[Peripheral nerve blocks of the lower extremities. Clinical and practical aspects]

Peripheral nerve blocks (PNBs) of the lower extremities are effective techniques for anesthesia and postoperative pain control. So far, these techniques have been used less frequently than PNBs of the upper limb. Nevertheless, growing awareness of complications of neuroaxial techniques, improved equipment and modern techniques for nerve localization have led to an increased use of PNBs of the lower limb. Anesthesiologists should be familiar with the anatomical basics and procedural details of these PNBs. They should also know the typical complications and side-effects and thoroughly inform patients about such potential problems. Continuous PNBs (perineural catheters) allow the benefits of PNBs to be prolonged into the postoperative period. Compared to continuous neuroaxial techniques continuous PNBs are equally effective for pain control but seem to be associated with fewer complications and side-effects.

Major complications associated with femoral nerve catheters for knee arthroplasty: a word of caution

One thousand one hundred ninety patients underwent knee arthroplasty between January 2004 and July 1, 2007, and received an indwelling continuous infusion femoral catheter for postoperative ropivicaine pump infusion. Catheters were placed using electrical stimulation guidance. For the initial 469 patients (group 1), the continuous infusion ran for 2 to 3 days. In 721 patients, the infusion was discontinued 12 hours after surgery. There were 9 femoral nerve palsies (2 in group 1, 7 in group 2) and 8 major falls (0.7%). The overall complication rate was 1.5%, and the risk of permanent nerve injury was 0.2%. Patients should be made aware of these complications as part of the usual informed consent process before using this technique for postoperative pain control after knee arthroplasty. We did not observe fewer falls when the continuous infusion was stopped 12 hours after surgery.

Does regional anesthesia improve outcome after total knee arthroplasty?

Total knee arthroplasty (TKA) is amenable to various regional anesthesia techniques that may improve patient outcome. We sought to answer whether regional anesthesia decreased mortality, cardiovascular morbidity, deep venous thrombosis and pulmonary embolism, blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether regional anesthesia improved rehabilitation. To do so, we performed a systematic review of the contemporary literature comparing general anesthesia and/or systemic analgesia with regional anesthesia and/or regional analgesia for TKA. To reflect contemporary surgical and anesthetic practice, only randomized, controlled trials from 1990 onward were included. We identified 28 studies involving 1538 patients. There was insufficient evidence from randomized, controlled trials alone to conclude if anesthetic technique influenced mortality, cardiovascular morbidity other than postoperative hypotension, or the incidence of deep venous thrombosis and pulmonary embolism when using thromboprophylaxis. Our review suggests there was no difference in perioperative blood loss or duration of surgery in patients who received general anesthesia versus regional anesthesia. Compared with general anesthesia and/or systemic analgesia, regional anesthesia and/or analgesia reduced postoperative pain, morphine consumption, and opioid-related adverse effects. Length of stay may be reduced and rehabilitation facilitated for patients undergoing regional anesthesia and analgesia for TKA.

Neurological complication analysis of 1000 ultrasound guided peripheral nerve blocks for elective orthopaedic surgery: a prospective study

Little data exists regarding the frequency of neurological complications following ultrasound guided peripheral nerve blockade. Therefore, we studied single injection and continuous ultrasound guided interscalene, supraclavicular, infraclavicular, femoral and sciatic nerve blocks in patients undergoing orthopaedic extremity surgery. All patients were contacted during postoperative weeks 2-4 and questioned for numbness or altered sensation anywhere in the involved extremity, and pain or weakness unrelated to surgery. The presumed aetiology of symptoms was based on the collective agreement of principal investigator, primary surgeon and a neurologist. Multivariate analysis was performed for characteristics potentially important in the causation of neurological complications. Of 1010 consecutive blocks, successful follow up between weeks 2 and 4 occurred in 98.6%. New, all-cause, neurological symptoms were present in 56/690 blocks (8.2%) at day 10, 37/1010 (3.7%) at 1 month and 6/1010 (0.6%) at 6 months. Most symptoms were due to causes unrelated to the block. Of 452 patients directly questioned at the time of the block, new neurological symptoms were more common in patients who experienced procedure-induced paraesthesia (odds ratio = 1.7, p = 0.029). The postoperative neurological symptom rate in this series is very similar to those previously reported following traditional techniques.

Transient neurologic syndrome after spinal anesthesia with epidural steroid treatment

BACKGROUND

Transient neurologic syndrome (TNS) is a rare complication of spinal and epidural anesthesia. It is defined as paradoxic postoperative back pain radiating to the lower extremities with no neurologic deficits. Because it is a self-limited disease, the treatment is usually symptomatic and consists of NSAIDs and injections of a neuromuscular-blocking drug at the trigger points. The syndrome may be resistant to this treatment regimen and may last for several months, resulting in a long convalescence.

CASE SUMMARY

A 63-year-old Turkish woman (height, 165 cm; weight, 71 kg) underwent hemorrhoidectomy in the jackknife position using spinal anesthesia. No adverse events occurred during puncture or surgery or in the immediate postoperative recovery period. Recovery from the sensory and motor block was normal. Twenty-four hours after surgery, lower limb and plantar pain developed with no sensory or motor deficit. Neurologic examination revealed normal motor and sensory function. Electroneuromyography showed partial denervation potential of muscles innervated by the left sciatic nerve. The symptoms were suggestive of TNS. Combination oral NSAID treatment with amitriptyline (25 mg/d) and gabapentin (1200 mg/d) was initiated. Because the pain still persisted 6 weeks after surgery, epidural steroid injection with triamcinolone acetate (80 mg) with isotonic saline was administered, resulting in definite pain relief (visual analog scale score = 0).

CONCLUSIONS

Epidural steroid treatment was effective in this patient with TNS resistant to treatment with NSAIDs, amitriptyline, and gabapentin. Future studies are needed to evaluate this treatment.

Does regional anaesthesia improve outcome after total hip arthroplasty? A systematic review

Total hip arthroplasty (THA) is amenable to a variety of regional anaesthesia (RA) techniques that may improve patient outcome. We sought to answer whether RA decreased mortality, cardiovascular morbidity, deep venous thrombosis (DVT) and pulmonary embolism (PE), blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether RA improved rehabilitation. To do so, we performed a systematic review of the contemporary literature to compare general anaesthesia (GA) and RA and also systemic and regional analgesia for THA. To reflect contemporary surgical and anaesthetic practice, only randomized controlled trials (RCTs) from 1990 onward were included. We identified 18 studies involving 1239 patients. Only two of the 18 trials were of Level I quality. There is insufficient evidence from RCTs alone to conclude if anaesthetic technique influenced mortality, cardiovascular morbidity, or the incidence of DVT and PE when using thromboprophylaxis. Blood loss may be reduced in patients receiving RA rather than GA for THA. Our review suggests that there is no difference in duration of surgery in patients who receive GA or RA. Compared with systemic analgesia, regional analgesia can reduce postoperative pain, morphine consumption, and nausea and vomiting. Length of stay is not reduced and rehabilitation does not appear to be facilitated by RA or analgesia for THA.

[Neurological complication after a vertical infraclavicular brachial plexus block. Case report of possible differential diagnoses of a neurological deficit]

A 72-year-old man with an obliteration of the brachial artery received a vertical infraclavicular block (VIP) for vascular surgery but 20 h after the operation a complete paresis of the affected extremity occurred. A new vascular obliteration could be excluded. During the diagnostic examination the patient noticed a snapping noise in the cervical column when moving his head and an abrupt recovery of the neurological deficits occurred. The radiological diagnostic provided no indication of cerebral ischemia or lesions of the brachial plexus. An additional diagnostic finding was a profound herniated vertebral disc with compression of the myelon. Fortunately, the neurological deficits completely returned to normal.