Jung-Shun Lee

Clinical and Ultrasonographic Results of Ultrasonographically Guided Percutaneous Radiofrequency Lesioning in the Treatment of Recalcitrant Lateral Epicondylitis

Background: In patients with lateral epicondylitis recalcitrant to nonsurgical treatments, surgical intervention is considered. Despite the numerous therapies reported, the current trend of treatment places particular emphasis on minimally invasive techniques. Purpose: The authors present a newly developed minimally invasive procedure, ultrasonographically guided percutaneous radiofrequency thermal lesioning (RTL), and its clinical efficacy in treating recalcitrant lateral epicondylitis. Study Design: Case series: Level of evidence, 4. Methods: Thirty-four patients (35 elbows), with a mean age of 52.1 years (range, 35-65 years), suffered from symptomatic lateral epicondylitis for more than 6 months and had exhausted nonoperative therapies. They were treated with ultrasonographically guided RTL. Patients were followed up at least 6 months by physical examination and 12 months by interview. The intensity of pain was recorded with a visual analog scale (VAS) score. The functional outcome was evaluated using grip strength, the upper limb Disability of Arm, Shoulder and Hand (QuickDASH) outcome measure, and the Modified Mayo Clinic Performance Index (MMCPI) for the elbow. The ultrasonographic findings regarding the extensor tendon origin were recorded, as were the complications. Results: At the time of the 6-month follow-up, the average VAS score in resting (from 4.9 to 0.9), palpation (from 7.6 to 2.5), and grip (from 8.2 to 2.9) had improved significantly compared with the preoperative condition (P < .01). The grip strength (from 20.6 to 27.0 kg) and QuickDASH score (from 54.3 to 21.0) had also improved significantly (P < .01). The MMCPI score improved from “poor” to “excellent.” The ultrasonographic finding revealed that the thickness of the common extensor tendon origin did not change significantly. At the final follow-up (mean, 14.3 months; range, 12-21 months), the patients reported a 78% reduction in pain compared with the preoperative status. No major complications were noted in any patient. Conclusion: Ultrasonographically guided RTL for recalcitrant lateral epicondylitis was found to be a minimally invasive treatment with satisfactory results in this pilot investigation. This innovative method can be considered as an alternative treatment of recalcitrant lateral epicondylitis before further surgical intervention.

Effects of topical corticosteroids on the sciatic nerve: an experimental study to adduce the safety in treating carpal tunnel syndrome

Despite known detrimental effects on the blood flow and histology of nerves after intraneural corticosteroid injection, the neurotoxic effect of corticosteroids remains unclear. We investigated the effect of topical dexamethasone on nerve function. Two sponge strips soaked with dexamethasone at doses of 0.8, 1.6, and 3.2 mg were placed under and over the left sciatic nerve of adult Wistar rats for 30 minutes. Mixed-nerve-elicited somatosensory evoked potentials and dermatomal somatosensory evoked potentials were evaluated immediately and repeated together with functional tests and histology 2 weeks later. Evoked potential amplitude was dose-dependently lower and latency was prolonged in dexamethasone-treated sciatic nerves compared to controls. The suppression persisted with incomplete recovery for at least 4 hours, but differences between treated and control nerves were not significant after 2 weeks. Topical dexamethasone adversely affected neural conduction in a dose-dependent manner. Our results suggest that caution is required when using large doses of corticosteroid for injection of the carpal tunnel.

Delayed Granulocyte Colony-Stimulating Factor Treatment Promotes Functional Recovery in Rats With Severe Contusive Spinal Cord Injury

Study Design. We used a severe contusive spinal cord injury (SCI) model and electrophysiologic, motor functional, immunohistochemical, and electron microscopic examinations to analyze the neuroprotective effects of delayed granulocyte colony-stimulating factor (G-CSF) treatment. Objective. To determine the neuroprotective effects of delayed G-CSF treatment using multimodality evaluations after severe contusive SCI in rats. Summary of Background Data. Despite some reports that G-CSF treatment in the acute stage of different central nervous system injury models was neuroprotective, it has not been determined whether delayed G-CSF treatment can promote neural recovery in severe contusive SCI. Methods. Rats with severe contusive SCI were divided into 2 groups: G-CSF group rats were given serial subcutaneous injections of G-CSF, and control group rats (controls) were given only saline injections on postcontusion days 9 to 13. Using the Basso-Beattie-Bresnahan scale and cortical somatosensory evoked potentials, we recorded functional evaluations weekly. The spinal cords were harvested for protein and immunohistochemical analysis, and for electron microscopy examination. Results. The preserved spinal cord area was larger in G-CSF group rats than in control group rats. Both sensory and motor functions improved after G-CSF treatment. Detachment and disruption of the myelin sheets in the myelinated axons were significantly decreased, and axons sprouted and regenerated. There were fewer microglia and macrophages in the G-CSF group than in the control group. The levels of brain-derived neurotrophic factor were comparable between the 2 groups. Conclusion. Delayed G-CSF treatment at the subacute stage of severe contusive SCI promoted spinal cord preservation and improved functional outcomes. The mechanism of G-CSFs protection may be related in part to attenuating the infiltration of microglia and macrophages.

Neurophysiological and histopathological evaluation of low-dose radiation on the cauda equina and postlaminotomy fibrosis: an experimental study in the rat.

Study Design. We evaluated the electrophysiological changes to the cauda equina after low-dose external irradiation in a postlaminotomy fibrosis model in rats. Objective. To clarify the immediate and long-term electrophysiological responses of antifibrotic radiation therapy in a fibrosis model. Summary of Background Data. Low-dose perioperative radiation therapy inhibits scar formation. However, its efficacy for preventing fibrosis-induced compressive neuropathy and its potential adverse effect on underlying neural structures have not been studied. Methods. Twenty-four rats were placed in 3 groups of 8: group I, sham operation (laminar exposure alone) with a single fraction of 700 cGy external irradiation given using a 9-MeV electron beam 24 hours postsurgery; group II, left L5 hemilaminectomy (laminotomy) alone; and group III, left L5 hemilaminectomy with the same radiation protocol as group 1. We recorded mixed-nerve-elicited somatosensory-evoked potentials (M-SSEP)- and dermal (D)-SSEP at the thoracolumbar junction, and L1–L2 interspinous ligament after percutaneously stimulating the posterior tibial nerve at the bilateral medial ankle and L5 dermatomal fields. We compared the potentials recorded immediately before, 30 minutes, 2 weeks, and 1, 2, and 3 months after surgery on the operated and nonoperated sides. We used gross dissection and histologic sections to evaluate the degree of perineural fibrosis and walking-track analysis for neurologic evaluation. Results. Pre- and postoperative (30 minutes and 2 weeks) M- and D-SSEP were not statistically different. In group II, the relative amplitude of D-SSEP (elicited from 5 dermatomes) 1, 2, and 3 months postsurgery was lower; however, the M-SSEP in all groups and D-SSEP of groups I and III remained constant. Histologic evaluation of radiation efficacy showed that the frequency and extent of peridural fibrosis was consistently lower in group II than in group III. Conclusion. Low-dose irradiation reduced peridural fibrosis and prevented fibrosis-induced radiculopathy. The radiation caused no adverse neuropathic complications.

Spinal cord injury enhances arterial expression and reactivity of α1-adrenergic receptors—mechanistic investigation into autonomic dysreflexia

BACKGROUND CONTEXT Autonomic dysreflexia (AD) usually presents with a significant increase in blood pressure, and uncontrollable autonomic response to stimuli below the level of spinal cord injury (SCI). PURPOSE This study analyzed the vasomotor function and molecular changes in the peripheral arteries below the lesion of SCI to characterize the mechanism of autonomic dysreflexia. STUDY DESIGN This was a randomized experimental study in rats. METHODS Contusive SCI was induced using a force-calibrated weight-drop device at the T10 level in anesthetized rats. Two weeks after severe SCI, blood flow in the femoral arteries was measured, and the vasomotor function and expression of α1-adrenergic receptors were analyzed. RESULTS Blood flow in the femoral artery was significantly reduced in rats with SCI (8.0±2 vs. 17.5±4 mL/min, SCI vs. control, respectively; p=.016). The contraction responses of femoral artery segments to cumulative addition of α1-adrenergic agonist phenylephrine were significantly enhanced in rats with SCI. Expression of α1-adrenergic receptor was upregulated in the medial layer of femoral artery vascular homogenates of these rats. CONCLUSION Our study provides evidence demonstrating that prolonged denervation below the lesion level following SCI results in a compensatory increased expression of α1-adrenergic receptors in the arterial smooth muscle layer, thereby enhancing the responsiveness to α1-adrenergic agonist and potentiating the development of AD.

Efficacy of topical cross‐linked hyaluronic acid hydrogel in preventing post laminectomy/laminotomy fibrosis in a rat model

Post‐laminectomy/laminotomy epidural fibrosis (EF) has been implicated as an important cause of failed back syndrome (FBS). The various clinical approaches used to control EF yield mixed outcomes. Cross‐linked hyaluronic acid hydrogel (cHA) was synthesized to increase mechanical stability and residence time. We evaluated the therapeutic attenuation of proliferative EF in laminectomy/laminotomy groups treated and not treated with cHA. A bilateral T11‐L1 total laminectomy or unilateral T12 laminotomy was done on four groups (n = 10 each) of Sprague‐Dawley rats and then histologically examined 2 months post‐surgery: (I) laminectomy group treated with and (II) not treated with cHA, (III) laminotomy group treated with and (IV) not treated with cHA. The grade of EF, the diameters within the spinal canal, dura mater thickness, and the area of the epidural space, subarachnoid space, and conus medullaris space were assessed. The cHA‐treated subgroups (I, III) had a significantly lower grade of EF, thinner dura mater, and larger epidural and subarachnoid spaces than did the control subgroups (II, IV) (p < 0.05). The cHA formed a solid interpositional membrane barrier that prevented invasive fibrosis, and also helped reduce pathological changes to the adjacent structures. In conclusion, topically applied cHA is effective for reducing EF.

Isolated osteoradionecrosis of the dens mimicking metastasis of nasopharyngeal carcinoma after radiotherapy.

Nasopharyngeal carcinoma (NPC) is common in southern China, and radiotherapy remains the mainstay of treatment. A rare late complication of this treatment is the development of osteoradionecrosis (ORN), which seldom involves the cervical spine. We describe a 47-year-old female with undifferentiated carcinoma of the nasopharynx, stage II (T2N0M0), who had undergone radiotherapy 51 months prior, and complained of a twitching headache on neck flexion/extension. Imaging studies, including MRI and 18-fluoro-2-deoxyglucose positron emission tomography scan, suggested the diagnosis of cervical spinal metastasis. However, plasma Epstein-Barr virus DNA was undetectable, favoring absence of tumor recurrence. The patient underwent atlantoaxial sublaminar wiring for an unstable spine and a subsequent transoral biopsy, the histopathologic diagnosis of ORN. The postoperative clinical course was uneventful and follow-up MRI, 2 years later, revealed gradual resolution of the lesion. To our knowledge this is the first report of an isolated ORN lesion of the dens confirmed surgically in a patient with a history of previously treated NPC, a lesion at the cervical spine, and inconclusive imaging and biological marker results. We recommend that ORN be suspected until proven otherwise in a previously irradiated patient.

Changes in excursion and strain in the rat sciatic nerve under cauda equina compression induced by epidural balloon inflation.

BACKGROUND CONTEXT Healthy nerves are able to stretch and glide as responses to normal physiological movement. Injury to the nerve may alter the nerves mechanical properties and result in neuropathy. Whether cauda equina compression alters the mechanical properties of the sciatic nerve is still unclear. PURPOSE The purpose of this study was to demonstrate the changes in excursions and strains of the sciatic nerve in vivo after acute cauda equina compression was induced by epidural balloon compression. STUDY DESIGN An animal comparative study with induced cauda equina compression was designed for in situ measurements of nerve properties. METHODS Twenty-six adult Sprague-Dawley rats were divided into three groups. The balloon group (n=10) underwent epidural compression induced by inflation of an embolectomy balloon catheter that was inserted through an L6 laminotomy. The control group (n=10) underwent laminotomy but without compression. The normal group (n=6) received no back surgery. This model of neuropathy was confirmed with electrophysiological examination. The excursions and strains of the sciatic nerve in response to the modified straight leg-raising (SLR) test were measured in situ and analyzed. RESULTS The scales of the excursions were lower in the balloon group than in the other two groups, in both 90° flexion and extension of the knee. The balloon group was more sensitive to positional changes. The strain was significantly higher under the condition of epidural balloon compression. CONCLUSIONS We concluded that cauda equina compression decreased the excursion and increased the strain of the sciatic nerve in response to a modified SLR test. These findings might indicate one of the mechanisms of the pain provoked by the SLR test and also possibly contribute to an understanding of the pathogenesis of the neuropathy in the lower limbs of patients with cauda equina compression.

Lumbar intraspinal arachnoid cyst superimposed by hyperacute spinal subdural hematoma: an unusual case

BACKGROUND CONTEXT Lumbar intradural arachnoid cyst (AC) concomitant with hyperacute spinal subdural hematoma (SSDH) has never been reported in the literature. PURPOSE To report a case of lumbar AC superimposed by hyperacute SSDH, which was difficult to diagnose preoperatively using magnetic resonance imaging. Herein, we describe diagrams showing the proposed mechanisms underlying the formation of a symptomatic AC. STUDY DESIGN/SETTING The study was designed to be a case report and literature review. METHODS A 65-year-old man presented with acute onset of low back pain, followed by 5-day history of numbness and weakness in both legs before admission. Magnetic resonance imaging of the lumbosacral spine revealed an intradural extramedullary biconvex lesion at the L3-L4 level; the lesion compressed the cauda equina posteriorly. The lesion mainly appeared as hyperintense on T2-weighted images and hypointense on T1-weighted images. On the basis of these findings, the lesion was preoperatively diagnosed as a symptomatic lumbar subdural AC that compressed the cauda equina. RESULTS The patient underwent laminectomy from L2 to L4. After a dura incision, a partially organized subdural hematoma was noted. Beneath the subdural hematoma was an AC compressing the underlying nerve roots. The patients back pain and muscle strength markedly improved after the operation. CONCLUSIONS Preoperative diagnosis of concomitant hyperacute SSDH and AC is difficult. In cases of patients who present with intraspinal AC accompanied by an acute onset of clinical presentation, an associated etiology should be considered until proven otherwise.

The effect of molecular weight and concentration of hyaluronan on the recovery of the rat sciatic nerve sustaining acute traumatic injury

Acute traumatic peripheral nerve injury remains a significant clinical issue affecting mostly young individuals and their productivity in spite of advances in current medicine. Hyaluronan has been explored in this scenario for its anti-adhesive and high biocompatibility properties for decades. The molecular weight and concentration of the locally applied hyaluronan has been overlooked and not optimized. We used different molecular weights and concentrations of hyaluronan in a rat sciatic nerve crush injury model and found better overall outcomes with high molecular weight (3000 kDa) hyaluronan. The anti-inflammatory effect of the higher molecular weight hyaluronan may have a more favorable effect. We conclude that the optimization of hyaluronan is necessary when incorporating hyaluronan in the engineering of biomaterials for use in acute traumatic peripheral nerve injury.