Neurophysiologic Mechanism of Pain

STUDY DESIGN: A review of the literature regarding neurophysiologic mechanism of pain. OBJECTIVES: To review and discuss neurophysiologic mechanism of pain, including neuropathic pain. SUMMARY OF LITERATURE REVIEW: The neurophysiology of pain has been established at the cellular and molecular biology level through many studies. Also, multiple modalities to manage pain have been developed. MATERIALS AND METHODS: A literature review. RESULTS: Pain develops by actions of multiple receptors, ion channels and neurotransmitters along the pain pathway. Pathologic states, such as persistent pain, allodynia, and hyperalgesia, arise from alteration of the pain pathway. Especially, neuropathic pain results from nerve injury and its pathology is rather different from the neuroplasty of normal individuals. CONCLUSION: Multiple modalities, including individualized pain treatment based on pain phenotype, are introduced. However, optimal treatment is uncertain, therefore, further studies are needed.

Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability Using a Gracilis Autograft without Bone Tunnel

BACKGROUND: Several tendon graft and fixation methods have been introduced in medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar dislocation. The purpose of this study was to evaluate the results of MPFL reconstruction using a gracilis autograft fixation without bone tunnel in patients with recurrent patellar instability. METHODS: Nine patients (four males and five females) diagnosed with recurrent patellar instability from July 2009 to January 2013 and had MPFL reconstruction using a gracilis autograft were included. The average age of the patients was 24.6 years (range, 13 to 48 years), and the average follow-up period was 19.3 months (range, 12 to 30 months). For every patient, femoral attachment was fixed using suture anchors securing the patella by suturing the periosteum and surrounding soft tissue. Clinical evaluation included the Kujala, Lysholm, and Tegner scores; in addition, patients were examined for any complication including recurrent dislocation. The congruence angle and patella alta were assessed radiologically before and after surgery. RESULTS: The Kujala score improved from an average of 42.7 ± 8.4 before surgery to 79.6 ± 13.6 (p = 0.008) at final follow-up; the Lysholm score improved from 45.8 ± 5.7 to 82.0 ± 10.5 (p = 0.008); and the Tegner score improved from 2.8 ± 0.8 to 5.6 ± 1.5 (p = 0.007). The Insall-Salvati ratio changed from 1.16 ± 0.1 (range, 0.94 to 1.35) before surgery to 1.14 ± 0.1 (range, 0.96 to 1.29; p = 0.233) at the final follow-up without significance. The congruence angle significantly improved from 26.5°± 10.6° (range, 12° to 43°) before surgery to -4.0°± 4.3° (range, -12° to 5°; p = 0.008) at final follow-up. Subluxation was observed in one patient and hemarthrosis occurred in another patient 2 years after surgery, but these patients were asymptomatic. CONCLUSIONS: We achieved good results with a patellar fixation technique in MPFL reconstruction using a gracilis autograft employing soft tissue suturing in patients with recurrent patellar dislocation.

Neurilemmoma in the Digital Nerve: 8 cases

As a rare cause of tumor in hand, we report eight cases of neurilemmoma in the digital nerve. Enucleation of the neurilemmoma under the microscopy resulted in complete relief of the symptoms at the latest follow-up.

Cubital Tunnel Syndrome Caused by Ulnar Nerve Schwannoma: A Case Report

As a rare cause of cubital tunnel syndrome, we report a case of cubital tunnel syndrome caused by Schwannoma of the ulnar nerve. Enucleation and subcutaneous anterior transposition of the ulnar nerve resulted in complete relief of the patient's symptoms.