Overall distribution pattern of the intramuscular nerves of the extraocular muscles and its clinical implications / Patrón de distribución general de los nervios intramusculares de los músculos extraoculares y sus implicaciones clínicas

SUMMARY: The purpose of this study was to reveal the overall distribution pattern of the intramuscular nerves of each extraocular muscle and provide morphological guidance for the selection of the neuromuscular compartment during extraocular muscle transplantation and target localization of the botulinum toxin A injection to correct strabismus. We studied 12 Chinese head specimens that were fixed with formalin. The extraocular muscles from both sides of each head were removed, and a modified Sihler's staining technique was used to reveal the overall distribution pattern of the intramuscular nerves. We observed an intramuscular nerve-dense region formed by the intramuscular arborized branches in the semitransparent superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, and levator palpebrae superioris muscles with Sihler's staining technique. The seven extraocular muscles can each be divided into two neuromuscular compartments. The intramuscular nerve-dense regions of the superior, inferior, medial, and lateral rectus and the superior oblique, inferior oblique, and levator palpebrae superioris muscles were positioned at 33.50 % -72.72 %, 40.21 % - 66.79%, 37.92 % - 64.51 %, 31.69 % - 56.01 %, 26.35 % - 64.98 %, 40.46 % - 73.20 %, and 27.72 % - 66.07 % of the lengths of the muscle bellies, respectively, and the centers of intramuscular nerve dense regions were located at 59.50 %, 54.18 %, 51.68 %, 50.08 %, 48.38 %, 56.49 %, and 50.77 % of the length of each muscle belly, respectively. The aforementioned values are the means of the actual values. These results suggest that when the strabismus is corrected with muscle transplantation, the extraocular muscle should be transplanted based on the neuromuscular compartment, which would benefit the function of both donor and recipient muscles. The localization of these nerve dense regions is recommended as an optimal target for the injection of botulinum toxin A to treat strabismus.

RESUMEN: El objetivo de este estudio fue revelar el patrón de distribución de los nervios intramusculares de cada músculo extraocular y, proporcionar una guía morfológica para la selección del compartimento neuromuscular durante el trasplante de músculo extraocular, y la localización de la inyección de toxina botulínica A para corregir el estrabismo. Estudiamos 12 muestras de cabezas de individuos chinos fijadas en formalina. Se extrajeron los músculos extraoculares de ambos lados de cada cabeza y, se utilizó una técnica de tinción de Sihler modificada para revelar el patrón de distribución general de los nervios intramusculares. Observamos una región densa en nervios intramusculares formada por los ramos intramusculares en los músculos recto superior semitransparente, recto inferior, recto medial, recto lateral, oblicuo superior, oblicuo inferior y elevador del párpado superior con técnica de tinción de Sihler. Los siete músculos extraoculares se pueden dividir cada uno en dos compartimentos neuromusculares. Las regiones intramusculares densamente nerviosas de los músculos recto superior, inferior, medial y lateral y los músculos oblicuo superior, oblicuo inferior y elevador del párpado superior se colocaron en 33,50 % -72,72 %, 40,21 % -66,79 %, 37,92 % -64,51 % , 31,69 % -56,01 %, 26,35 % -64,98 %, 40,46 % -73,20 % y 27,72 % -66,07 % de las longitudes de los vientres musculares, respectivamente, y los centros de las regiones densamente nerviosas intramusculares se ubicaron en 59,50 %, 54,18 % , 51,68 %, 50,08 %, 48,38 %, 56,49 % y 50,77 % de la longitud de cada vientre muscular, respectivamente. Los valores antes mencionados son medios de los valores reales. Estos resultados sugieren que cuando el estrabismo se corrige con trasplante de músculo, el músculo extraocular debe trasplantarse en función del compartimento neuromuscular, lo que beneficiaría la función tanto de los músculos donantes como receptores. Se recomienda la localización de estas regiones densas en nervios, como un objetivo óptimo para la inyección de toxina botulínica A para tratar el estrabismo.

Trochlear-oculomotor synkinesis: another congenital cranial dysinnervation disorder? / Sincinesia troclear-oculomotora: outro distúrbio congênito de denervação craniana?

ABSTRACT This report documents an unusual phenomenon. A 6-year-old girl with trochlear-oculomotor synkinesis presented with superior oblique and palpebral levator co-contraction. The literature was reviewed and the possibility of classifying this entity as a congenital cranial dysinnervation disorder was speculated.

RESUMO Este relato descreve um fenômeno incomum. Uma menina de 6 anos com sincinesia troclear-oculomotora apresentou co-contração do oblíquo superior e do levantador da pálpebra. A literatura foi revisada e especulou-se a possibilidade de classificar essa desordem como um distúrbio da congenital cranial dysinnervation disorder.

Blefaroplastia inferior transconjuntival associada à ressecção cutânea com preservação do músculo orbicular / Transconjunctival lower blepharoplasty with skin resection and preservation of the orbicularis muscle

INTRODUÇÃO: A blefaroplastia inferior transconjuntival está cada vez sendo mais utilizada pelos cirurgiões por ser uma técnica reprodutível e com baixo índice de complicações quando comparada à via transcutânea. Esta técnica tem como vantagens em relação à transcutânea a preservação do septo orbital, da lamela média e a manutenção da inervação do músculo orbicular. Este estudo tem o objetivo de analisar os resultados e as complicações da blefaroplastia transconjuntival com ressecção de pele na pálpebra inferior sem descolamento em uma amostra de pacientes. MÉTODO: Foram avaliados 18 pacientes submetidos a esta cirurgia, associada ou não à cantopexia lateral. A técnica cirúrgica é descrita detalhadamente. RESULTADOS: Um total de 16 pacientes femininos e 2 masculinos foram avaliados, com idade média de 52,7 anos. Houve melhora do aspecto do aumento de volume da pálpebra inferior, da flacidez de pele e da flacidez ligamentar lateral em todos os casos. Não foram registradas complicações tardias como retrações palpebrais, ectrópio, cicatrizes inestéticas, diplopia ou bolsas gordurosas remanescentes. Em nenhum caso foi necessária reintervenção cirúrgica. CONCLUSÃO: A blefaroplastia inferior transconjuntival com ressecção cutânea sem descolamento e preservação do músculo orbicular, associada ou não à cantopexia, se mostrou uma excelente técnica, facilmente reprodutível, confiável, segura e com poucas complicações pós-operatórias para o tratamento das alterações senis das pálpebras inferiores.

INTRODUCTION: Transconjunctival lower blepharoplasty is increasingly used by surgeons, since it is reproducible and has a low rate of complications compared to transcutaneous technique. The advantage of the transconjunctival technique is the preservation of the orbital septum, middle lamella, and orbicularis muscle innervation. This study aims to assess the results and complications of transconjunctival blepharoplasty with skin resection in the lower eyelid without detachment. METHOD: Eighteen patients who underwent this surgery with or without lateral canthopexy were analyzed. The surgical technique is described in detail. RESULTS: A total of 16 female and 2 male patients were assessed, with an average age of 52.7 years. There was improvement in all cases in the appearance of increased volume in the lower eyelid, and a decrease in skin and lateral ligament laxity. Late complications such as eyelid retraction, ectropion, unaesthetic scars, diplopia, or remnant fat bags were not observed. Surgical reintervention was not required in any cases. CONCLUSION: Transconjunctival lower blepharoplasty with skin resection without detachment and with preservation of the orbicularis muscle, with or without canthopexy, is an excellent technique, and is easily reproducible, reliable, and safe, with few postoperative complications in treatment of age-related changes in the lower eyelids.

Innervated Myotendinous Cylinders Alterations in Human Extraocular Muscles in Patients With Strabismus

PURPOSE: To analyze innervated myotendinous cylinders (IMCs) in the extraocular muscles (EOMs) of normal subjects and strabismic patients. METHODS: The rectus muscles of 37 subjects were analyzed. Distal myotendinous specimens were obtained from 3 normal subjects, 20 patients with acquired strabismus, 11 with infantile strabismus, and from 3 with congenital nystagmus, and were studied by using light microscopy. Some specimens (6 rectus muscles) were also examined by transmission electron microscopy. RESULTS: IMCs were found in the distal myotendinous regions of EOMs. The IMCs of patients with acquired strabismus showed no significant morphological alterations. However, significant IMCs alterations were observed at the distal myotendinous junction of patients with congenital strabismus and congenital nystagmus. CONCLUSIONS: This study supports the notion that IMCs in human EOMs function mainly as proprioceptors, along with effector properties, and a disturbance of ocular proprioceptors plays an important role in the pathogenesis of oculomotor disorder. We suggest that a proprioceptive feedback system should be stimulated and calibrated early in life for the development of binocular vision.

Estrabismo paralítico: revisão de 24 anos da Santa Casa de São Paulo / Paralytic strabismus: review of 24 years at \"Santa Casa de São Paulo\"

OBJETIVO: Avaliar a incidência, etiologia e evolução dos estrabismos paralíticos ou paréticos. MÉTODOS: Foram selecionados retrospectivamente 519 prontuários de pacientes com paresia ou paralisia isolada dos músculos inervados pelos III, IV ou VI nervos cranianos, a partir de 11.000 prontuários da Seção de Motilidade Extrínseca Ocular do Departamento de Oftalmologia da Santa Casa de São Paulo de janeiro de 1980 a outubro de 2004. Foram estudados: o nervo craniano acometido, o olho acometido, o sexo, os fatores etiológicos e a evolução desses pacientes. RESULTADOS: Dos 519 pacientes, 17,1 por cento foram casos congênitos e 82,9 por cento foram adquiridos. O nervo craniano mais afetado foi o VI (49,7 por cento). Os pacientes do sexo masculino foram mais acometidos, com 58,1 por cento dos casos. A etiologia traumática foi a mais freqüente nos casos de paresia ou paralisia de III (43,0 por cento), IV (52,4 por cento) e VI (48,8 por cento) nervos cranianos. Os pacientes evoluíram mais freqüentemente para cirurgia nos três grupos: III nervo (42,9 por cento), IV nervo (73,2 por cento) e VI nervo (43,2 por cento). CONCLUSÃO: O VI nervo craniano foi o mais freqüentemente acometido e o fator etiológico mais importante foi o traumatismo, dados esses que coincidem com os encontrados na literatura.

PURPOSE: To describe the incidence, etiologies and follow-up of patients with paralytic strabismus. METHODS: Retrospective study of 519 strabismic patients with isolated III, IV or VI cranial nerve palsy of 11,000 charts of the Ocular Motility Section of the Department of Ophthalmology of "Faculdade de Ciências Médicas Santa Casa de São Paulo", Brazil, between January 1980 and October 2004. This study analyzed: the injured cranial nerve, affected eye, sex distribution, etiology and follow-up. RESULTS: It was found that 17.1 percent of the cases were congenital and 82.9 percent acquired. The VI cranial nerve was the most frequently affected (49.7 percent). The incidence was higher in males (58.1 percent). Traumatism was the most common cause of III (43.0 percent), IV (52.4 percent) and VI (48.8 percent) nerve palsy. Surgery was performed in the three groups: third nerve (42.9 percent), fourth nerve (73.2 percent) and sixth nerve (43.2 percent). CONCLUSIONS:The sixth cranial nerve was the most frequently affected and the most common cause was traumatism, the same as observed in the literature.

Afferent projections from motoneurons innervating extraocular muscles to the cerebellum demonstrated by the retrograde double-labeling technique.

The objective of this study was to investigate the characteristics and distributions of neuronal origin of cerebellar afferents from motor cranial nerve nuclei innervating extraocular muscles by the method of retrograde transport of two fluorescence tracers in rats. Under deep anesthesia and aseptic conditions, 5 microl of 3% solution of Fluoro-Gold (FG) in phosphate buffer solution (PBS) was injected into the bellies of the six extraocular muscles to study the labeling of motoneurons innervating corresponding extraocular muscles. The cerebellum was exposed by craniotomy, and 0.3 microl of 10% solution of Dextran Tetramethyl Rhodamine Biotin (Micro Ruby: or MR) in PBS was injected into many regions of the anterior vermis (lobule I, II) and the posterior vermis (lobule VI, VII, IX, X), the flocculus, the paraflocculus and the deep cerebellar nuclei. Multiple injections were made to cover the entire cerebellum in order to obtain a near maximum labeling of cerebellar afferent neurons. In other cases, only small single or a few injections were made in specific areas of the cerebellum to study specific distributions and topographic organization. In one group of rats, injections were made both in the extraocular muscles with FG and in the cerebellum with MR to study the double labeling of neurons, which project their axons to both the extraocular muscle and the cerebellum. Another group of rats were injected in both sites with only PBS and served as the control for auto-fluorescence background. After 3 days postoperative survival time, all animals were deeply reanesthetized and perfused with heparinized normal saline solution, followed by 4% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4, and 30% sucrose solution in PBS. The brainstem and the cerebellum were removed immediately, and stored in sucrose solution in PBS at 4 degrees C. Serial transverse sections of the brainstem and sagittal sections of the cerebellum were obtained by a freezing microtome at 40 microm thickness, collected on uncoated glass slides, and immediately dried. All sections were examined under an epifluorescence or confocal microscope equipped with filter systems for FG and MR. The presence of both single and double retrograde labeled neurons in the Oculomotor (CN 3), Trochlear (CN 4) and Abducens (CN 6) nuclei was recorded, photographed, stored as computer images files and printed out as hard copies. The labeling neurons in the vicinity of the CN 3, 4, 6 from all sections were plotted onto diagrams and counted Neurons labeled only with MR retrogradely transported from injection sites in the cerebellum were found bilaterally and scattered throughout in the Oculomotor, Trochlear and Abducens nuclei. These neurons labeled only with MR were small and medium-sized interneurons and represented only a small proportion of the entire population. Neurons labeled only with FG retrogradely transported from injection sites in the extraocular muscles were the most numerous, and distributed almost throughout the entire population of small, medium-sized and large motoneurons, which innervate the extraocular muscles. A smaller proportion of small and medium-sized FG labeled neurons within these nuclei were also double labeled with MR, indicating that they project their axon collaterals to both extraocular muscles and the cerebellum. In conclusion, the present findings provide clear anatomical evidence that a small population of motoneurons in the Oculomotor, Trochlear and Abducens nuclei of the rat project their axon collaterals directly to the cerebellum and the extraocular muscle, in addition to the cerebellar afferents from other interneurons within these nuclei. The findings also indicate that cerebellar neuronal circuits play more direct roles in monitoring and controlling eye movements than previously known.

Ultrastructural Changes of Myotendinous Nerve Endings following Recession or Resection Procedures of Extraocular Muscle Surgeries in Cats

To verify the postoperative ultrastructural changes of the myotendinous nerve endings of feline extraocular muscles, which are known as proprioceptors. Sixteen recti of four cats were used and divided into three groups. In group A, eight lateral recti were recessed. In group B, four medial recti were resected by 10 mm from insertion to include the myotendinous junction. In group C, four medial recti were resected by 4 mm of muscle bellies only, without disturbing the myotendinous junction. Four weeks after surgery, specimens were examined with electron microscopy. In group A, overall neural structures were well maintained with slight axonal degeneration. In group B, only muscle fibers were observed without any regeneration of neural sprouts. In group C, axonal disintegration and shrinkage were evident. These results indicate that myotendinous nerve endings can be damaged in strabismus surgery, and that resection was more invasive than recession in disrupting myotendinous nerve endings.

Fenômeno de Marcus Gunn: diagnóstico diferencial das ptoses palpebrais na criança / Marcus Gunn Phenomenon: differential diagnosis of palpebral ptoses in children

OBJETIVO: Este trabalho teve por objetivo fazer uma revisão bibliográfica, relatar e discutir o caso clínico de um paciente com fenômeno de Marcus Gunn. DESCRIÇAO: Criança de 5 anos de idade, sexo feminino, hígida. Nos primeiros meses de vida, em consulta de puericultura, foi detectada alteração no olho direito, que, a princípio, parecia tratar-se de estrabismo. Após consultas com vários oftalmologistas, não se alcançou um diagnóstico preciso. Já aos 4 anos de idade, após exame realizado por oftalmologista pediátrico, confirmou-se o diagnóstico do fenômeno de Marcus Gunn. O restante do exame físico, incluindo exame neurológico, estava normal. Por se tratar de ptose palpebral leve, sem outras patologias associadas, optou-se por uma conduta conservadora. COMENTARIOS: Este relato visa alertar os pediatras com relação ao fenômeno de Marcus Gunn, que ainda é pouco conhecido. A partir deste conhecimento, o pediatra poderá identificar o fenômeno, possibilitando o encaminhamento precoce para a abordagem de complicações ou condições associadas, além de diagnóstico diferencial com outros tipos de ptose palpebral.

Alteraciones motoras: segunda parte; alteraciones de las ducciones / Motor alterations: second part; alteration in ductions

Se describen las alteraciones de las ducciones en cuatro grupos: por parálisis: III par, IV par, VI par; por hipofunción: agenesia muscular, sección traumática del músculo, debilitamiento quirúrgico excesivo, músculo suelto; por alteraciones inervacionales: síndrome de Duane, parálisis monocular de elevadores, síndrome de Moebius; por restricción: síndrome de Brown, estrabismo fijo, fibrosis del recto inferior, estrabismo tiroideo, fractura blow-out de órbita, adhesión post-quirúrgica

Teste de equilíbrio de forças elásticas do olho / The spring back balance test in eye

Realizou-se em trinta e um pacientes com estrabismo horizontal, o teste do equilíbrio de forças elásticas (TEFE), um teste per-operatório que avalia o equilíbrio ou desequilíbrio de forças antagônicas do olho, permitindo a análise da posiçäo de repouso mecânico. Analisou-se o TEFE antes e ao final da cirurgia em pacientes estrábicos sob anestesia geral profunda. Mediu-se, com a pinça de Scott-Collins-O'Meara, a força necessária para produzir um deslocamento do olho de 10mm a partir da posiçäo de repouso, e com régua milimetrada a extensäo de movimento de retorno do olho quando liberado. Quando os resultados do TEFE foram comparados com o angulo do desvio, um mês após a cirurgia, a análise de regressäo estatística foi näo significativa. Portanto o TEFE näo foi um bom indicador do sucesso cirúrgico e seus resultados näo devem alterar o planejamento cirúrgico pré-operatório em pacientes com estrabismo comitante horizontal.