A Computed Tomography-Based Anatomic Comparison of Three Different Types of C7 Posterior Fixation Techniques : Pedicle, Intralaminar, and Lateral Mass Screws

OBJECTIVE: The intralaminar screw (ILS) fixation technique offers an alternative to pedicle screw (PS) and lateral mass screw (LMS) fixation in the C7 spine. Although cadaveric studies have described the anatomy of the pedicles, laminae, and lateral masses at C7, 3-dimensional computed tomography (CT) imaging is the modality of choice for pre-surgical planning. In this study, the goal was to determine the anatomical parameter and optimal screw trajectory for ILS placement at C7, and to compare this information to PS and LMS placement in the C7 spine as determined by CT evaluation. METHODS: A total of 120 patients (60 men and 60 women) with an average age of 51.7+/-13.6 years were selected by retrospective review of a trauma registry database over a 2-year period. Patients were included in the study if they were older than 15 years of age, had standardized axial bone-window CT imaging at C7, and had no evidence of spinal trauma. For each lamina and pedicle, width (outer cortical and inner cancellous), maximal screw length, and optimal screw trajectory were measured, and the maximal screw length of the lateral mass were measured using m-view 5.4 software. Statistical analysis was performed using Student's t-test. RESULTS: At C7, the maximal PS length was significantly greater than the ILS and LMS length (PS, 33.9+/-3.1 mm; ILS, 30.8+/-3.1 mm; LMS, 10.6+/-1.3; p<0.01). When the outer cortical and inner cancellous width was compared between the pedicle and lamina, the mean pedicle outer cortical width at C7 was wider than the lamina by an average of 0.6 mm (pedicle, 6.8+/-1.2 mm; lamina, 6.2+/-1.2 mm; p<0.01). At C7, 95.8% of the laminae measured accepted a 4.0-mm screw with a 1.0 mm of clearance, compared with 99.2% of pedicle. Of the laminae measured, 99.2% accepted a 3.5-mm screw with a 1.0 mm clearance, compared with 100% of the pedicle. When the outer cortical and inner cancellous height was compared between pedicle and lamina, the mean lamina outer cortical height at C7 was wider than the pedicle by an average of 9.9 mm (lamina, 18.6+/-2.0 mm; pedicle, 8.7+/-1.3 mm; p<0.01). The ideal screw trajectory at C7 was also measured (47.8+/-4.8degrees for ILS and 35.1+/-8.1degrees for PS). CONCLUSION: Although pedicle screw fixation is the most ideal instrumentation method for C7 fixation with respect to length and cortical diameter, anatomical aspect of C7 lamina is affordable to place screw. Therefore, the C7 intralaminar screw could be an alternative fixation technique with few anatomic limitations in the cases when C7 pedicle screw fixation is not favorable. However, anatomical variations in the length and width must be considered when placing an intralaminar or pedicle screw at C7.

Estudo da origem acromial do músculo deltoide / The anatomy of the acromial deltoid muscle origin

As características macroscópicas da origem do músculo deltoide foram estudadas em 12 ombros de cadáveres. A origem acromial anterior e lateral do deltoide foi dissecada e analisada macroscopicamente com auxílio de computação gráfica. Determinamos as medidas dos diâmetros ântero-posterior do acrômio e do deltoide e suas respectivas áreas e, a seguir, realizamos simulações por computação de descompressões subacromiais de 4, 6 e 8 mm. As descompressões subacromiais simuladas de 8 mm, 6 mm e 4 mm desinserem 34,7%, 32 % e 29,1% da área de origem do deltoide, respectivamente. Concluímos que os diâmetros ântero-posteriores e as áreas do acrômio e deltoide possuem diferenças estatísticas significantes. Os diâmetros lateromediais do acrômio em relação ao deltoide não apresentam diferenças estatísticas, assim como a área do deltoide remanescente após uma descompressão subacromial de 4 mm, quando comparada com a área do acrômio.

Estudo anatômico do retalho perfurante ântero-lateral da coxa / Anatomic study of the anterolateral thigh flap

INTRODUÇÃO: O retalho ântero-lateral da coxa é baseado em vasos perfurantes do ramo descendente da artéria circunflexa lateral femoral. Este retalho tem características muito interessantes para a cirurgia reparadora, como a pequena espessura, pedículo longo e excelente área doadora. No entanto, existem muitas controvérsias na literatura quanto aos vasos perfurantes e ao trajeto do pedículo deste retalho. Neste trabalho procurou-se estabelecer alguns parâmetros anatômicos e esclarecer estas controvérsias. MÉTODO: Estudaram-se 100 coxas de 50 cadáveres quanto aos seguintes aspectos: 1- Número e localização de perfurantes encontrados, 2- Trajeto do pedículo perfurante, 3- Trajetória intramuscular, 4- Comprimento do trajeto intramuscular, 5- Comprimento total do pedículo, 6- Diâmetro dos vasos e 7- Espessura do retalho. RESULTADOS: 1- Encontraram-se de 0 a 4 perfurantes por coxa estudada, todas em um raio de até 6cm do ponto médio entre a espinha ilíaca ântero-superior e a borda lateral da patela. 2- Os vasos perfurantes tinham trajeto músculo-cutâneo em 75,76% das coxas e septo-cutâneo em 24,24%. 3- Dos pedículos perfurantes com trajeto músculo-cutâneo, 86,67% possuíam trajetória indireta contra 13,33% com trajetória direta. 4- O comprimento médio do trajeto intramuscular dos pedículos foi de 3,67 ± 2,01 cm. 5- O comprimento médio do pedículo total foi de 11,31 ± 3,12 cm. 6- O diâmetro médio da artéria na origem do ramo descendente da artéria circunflexa femoral foi de 2,21 ± 0,85 mm e para as veias no mesmo local de 2,66 ± 1,33 mm e 2,10 ± 1,11 mm. 7- A espessura da tela subcutânea foi de 8,98 ±6,23 mm e da pele de 1,60 ± 0,76 mm. CONCLUSÕES: 1- Existiu uma pequena possibilidade de não haver pedículos perfurantes. 2- Quando presentes, os pedículos perfurantes do ramo descendente da artéria circunflexa lateral femoral eram encontrados em numero de 1 a 4, sempre em um raio de 6 cm a partir do ponto médio entre a espinha ilíaca ântero-superior e a borda...

INTRODUCTION: The anterolateral thigh flap is based on the perforator vessels of the descending branch of the lateral circumflex femoral artery. This flap has very interesting characteristics for the reconstructive surgery, like the small thickness, long pedicle and excellent donor site. On the other hand, there are many controversial data on the literature about the perforator vessels and the pedicle course of this flap. The aims of this study are to establish some anatomical parameters and clear some controversies. METHOD: A hundred thighs of 50 cadavers were studied for: 1- The number and location of the perforator vessels. 2- The course of the perforator pedicles. 3- The intramuscular course. 4- The length of the intramuscular course. 5- The total length of the vascular pedicle. 6- The diameter of the vessels. and 7- The thickness of the flap. RESULTS: 1- There were found from 0 to 4 perforators per thigh, all in a 6cm radius from the mid point between the anterosuperior iliac spine and the lateral border of the patella. 2- The pedicles was musculocutaneous in 75,76% of the thighs and septocutaneous in 24,24%. 3- Among the musculocutaneous pedicles, 86,67% had a direct intramuscular course, and 13,33% had indirect course. 4- The mean length of the intramuscular course was 3,67 ± 2,01 cm. 5- The mean total pedicle length was 11,31 ± 3,12 cm. 6-The mean artery diameter on the origin of the descending branch of the lateral circumflex femoral artery was 2,21 ± 0,85 mm and the mean vein diameter on the same spot was 2,66 ±1,33 mm and 2,10 ± 1,11 mm. 7- The mean subcutaneous fat tissue thickness was 8,98 ± 6,23 mm and the mean skin thickness was e 1,60 ± 0,76 mm. CONCLUSIONS: 1- There was a possibility of finding no perforators of the descending branch of the lateral circumflex femoral artery. 2- When present, the perforators pedicles were found in numbers between 1 to 4, always in a 6cm radius from the mid point between the anterosuperior iliac spine...

Anterolateral thigh flap for head and neck reconstruction : anatomic study