Pathogenic Hydrogel? A Novel-Entrapment Neuropathy Model Induced by Ultrasound-Guided Perineural Injections.

Entrapment neuropathy (EN) is a prevalent and debilitative condition caused by a complex pathogenesis that involves a chronic compression-edema-ischemia cascade and perineural adhesion that results in excessive shear stress during motion. Despite decades of research, an easily accessible and surgery-free animal model mimicking the mixed etiology is currently lacking, thus limiting our understanding of the disease and the development of effective therapies. In this proof-of-concept study, we used ultrasound-guided perineural injection of a methoxy poly(ethylene glycol)-b-Poly(lactide-co-glycoilide) carboxylic acid (mPEG-PLGA-BOX) hydrogel near the rat's sciatic nerve to induce EN, as confirmed sonographically, electrophysiologically, and histologically. The nerve that was injected with hydrogel appeared unevenly contoured and swollen proximally with slowed nerve conduction velocities across the injected segments, thus showing the compressive features of EN. Histology showed perineural cellular infiltration, deposition of irregular collagen fibers, and a possible early demyelination process, thus indicating the existence of adhesions. The novel method provides a surgery-free and cost-effective way to establish a small-animal model of EN that has mixed compression and adhesion features, thus facilitating the additional elucidation of the pathophysiology of EN and the search for promising treatments.

Compressive optic neuropathy secondary to an allergic reaction to hyaluronidase. / Neuropatía óptica compresiva secundaria a reacción alérgica a hialuronidasa.

A 58 year-old woman presented with severe chemosis and ophthalmoparesis on her left eye 8hours after uncomplicated cataract surgery under sub-tenon anaesthesia. Recovery of extrinsic motility was observed after corticosteroid and antihistamine treatment, but a non-haemorrhagic papillary oedema and a concentric defect of visual field were found. It progressed to papillary atrophy with preserved central vision, but with a significant visual field constriction. The aetiological study revealed an allergy to hyaluronidase that was used as adjuvant to the anaesthesia. This complication needs to be promptly diagnosed and treated, as the swelling of the orbital tissues can cause damage to the optic nerve.

Anterior Cutaneous Nerve Entrapment Syndrome Possibly Triggered by Oral Contraceptives.

We herein report a teenage girl who had been taking oral contraceptive pills for three months and complained of left lower abdominal pain that had continued for two months. A physical examination indicated anterior cutaneous nerve entrapment syndrome (ACNES), although no abnormality was found in various biochemical and imaging examinations. The pain was only transiently ameliorated by trigger-point injection, and neurectomy surgery was eventually effective. Sex steroids can be involved in the progress of local tissue edema causing ACNES. ACNES should be considered in cases of abdominal pain in patients taking oral contraceptives.

Meralgia Paresthetica as a Presentation of Acute Appendicitis in a Girl With Acute Lymphoblastic Leukemia.

A 7-year-old girl with Philadelphia chromosome-positive acute lymphoblastic leukemia developed recurrent fever and meralgia paresthetica (MP) during chemotherapy, which resolved after administration of antibiotics. Five months after the onset of these symptoms, enhanced computed tomography showed a periappendiceal abscess extending into the psoas muscle. The cause of her fever and MP was thought to be appendicitis, which probably developed during induction chemotherapy but did not result in typical abdominal pain. Patients with recurrent fever and MP should be evaluated by imaging examinations including computed tomography to search for appendicitis.

Symptomatic ectopic bone formation after off-label use of recombinant human bone morphogenetic protein-2 in transforaminal lumbar interbody fusion.

OBJECT: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been approved for use in the lumbar spine in conjunction with the lumbar tapered cage. However, off-label use of this osteoinductive agent is observed with anterior fusion applications as well as with both posterior lumbar interbody fusion and transforaminal lumbar interbody fusion (TLIF). Complications using rhBMP-2 in the cervical spine have been reported. Although radiographic evidence of ectopic bone in the lumbar spine has been described following rhBMP-2 use, this finding was not previously believed to be of clinical relevance. METHODS: This study was a retrospective review of 4 patients who underwent minimally invasive spinal TLIF (MIS-TLIF) in which bone fusion was augmented with rhBMP-2 applied to an absorbable collagen sponge. Case presentations, operative findings, imaging data, and follow-up findings were reviewed. RESULTS: Four cases with delayed symptomatic neural compression following the off-label use of rhBMP-2 with MIS-TLIF were identified. CONCLUSIONS: Although previously believed to be only a radiographic finding, the development of ectopic bone following rhBMP-2 use in lumbar fusion can be clinically significant. This paper describes 4 cases of delayed neural compression following MIS-TLIF. The reader should be aware of this potential complication following the off-label use of rhBMP-2 in the lumbar spine.

Chemotherapy-induced neuropathy.

Increasingly, surgeons are becoming aware of the successful treatment of symptomatic peripheral neuropathy by surgical decompression of peripheral nerves. Armed with the knowledge that patients can have underlying neuropathy with overlying anatomic compressions, surgeons have affected improvement in diabetes-induced neuropathy, neuropathy of unknown etiology, and chemotherapy-induced neuropathy. This article details the most well-known culprits in chemotherapy-induced neuropathy and discusses the putative mechanisms of action, medical management, and surgical data.

Continuous spinal anaesthesia--evolution of a technique.

Continuous spinal anaesthesia is an established technique in which renewed interest has been generated by the availability of small bore catheters suitable for use in the subarachnoid space. Problems include technical difficulty, post dural puncture headache and maldistribution of local anaesthetic, the latter being implicated in the development of caudal equina lesions. Maldistribution of local anaesthetic may possibly be reduced by attempting to place the tip of the catheter at the apex of the lumbo-sacral curve and the use of local anaesthetic solution that is only marginally hyperbaric. This article is in the form of a short review together with an account of the authors' own studies of continuous spinal anaesthesia, conducted to assess the technique for peripheral vascular surgery.

Silicone gel infiltration of a peripheral nerve and constrictive neuropathy following rupture of a breast prosthesis.

Following rupture of a subpectoral breast prosthesis, massive amounts of silicone gel migrated into the arm of a patient. The patient developed painful paresthesias and decreased sensation in the cutaneous distribution of the superficial radial nerve. Nerve conduction studies showed both an increase in distal latency and decreased amplitude in this nerve compared with the normal opposite side. Subsequent neurolysis confirmed dense fibrosis surrounding the nerve. Silicone droplets also were observed within the thickened epineurium of the median nerve, but no electrophysiologic evidence of neuropathy occurred. Multiple debridements of the subcutaneous tissue of the arm were necessary. In one of these specimens, histologic sections demonstrated silicone gel infiltration of a subcutaneous nerve. This is the first reported case of silicone gel infiltration of a nerve and constrictive neuropathy associated with a prosthesis rupture.

[A case of lead neuropathy--importance of subclinical entrapment of nerves in lead neuropathy].

The patient was a left handed 25-year-old man who had worked in a vinyl chloride resin factory since July 1987 using lead stearate as a stabilizer. During the two years preceding hospitalization, he had been admitted three times for colicky abdominal pain with constipation and nausea. Anemia and proteinuria without causative diseases were pointed out. Because of progressive muscle weakness of hands which began since January 1989, he was admitted to our neurologic clinic on October 2 1989. Neurological examination showed severe atrophy of both small hand muscles without sensory disturbances. Left hand was predominantly affected, especially in interossei muscles. Laboratory findings are as follows; RBC 3.25 million/cu.mm: Hb 9.7 g/dl:blood lead concentration 100 micrograms/dl: urinary coproporphyrin 4503 micrograms/l: urinary delta-ALA 138 mg/l: and urinary lead excretion after 1 g CaEDTA infusion: 3938 micrograms/day. Electromyography of extensor carpi radialis, flexor carpi ulnaris and opponens showed increased polyphasic, long duration MUPs. Electromyography of dorsal interossei showed fibrillation. Nerve conduction study showed mildly decreased motor and sensory conduction velocities and markedly reduced amplitude of compound muscle action potentials (CAMPs). Investigation by inching method revealed conduction block of left ulnar nerve across elbow. After CaEDTA chelating therapy, 1 g once a week, steady improvement of muscular weakness was observed within a few months. Serial nerve condition studies revealed constant recovery of nerve conduction velocities, amplitude of CMAPs and diminution of conduction block across the left elbow. Conduction block across left elbow without sensory disturbances implies that subclinical cubital tunnel syndrome might have existed in this patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraneural steroid injection as a complication in the management of carpal tunnel syndrome. A report of three cases.

Steroid injection can provide symptomatic relief in patients with carpal tunnel syndrome (CTS). Its role should be limited to a diagnostic aid in cases in which symptoms are atypical, a temporizing agent in patients with severe symptoms either who are awaiting surgery or in whom spontaneous remission might be expected, and as a definitive treatment in patients who do not desire surgery. Injection should be performed using proper technique by physicians skilled in carpal tunnel surgery. A soluble preparation of dexamethasone is recommended. Immediate paresthesia in the median nerve distribution or exacerbation of symptoms beyond 48 hours following injection is suspect for inadvertent nerve injury; therefore, early surgical decompression is indicated.