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PubMed1999

Laparoscopic approach to L4-L5 for interbody fusion using BAK cages: experience in the first 58 cases.

STUDY DESIGN: Operative reports were reviewed for patients who underwent laparoscopic fusion at the L4-L5 level and information regarding the mobilization of the vessels was recorded. OBJECTIVE: The purpose of this study was to describe variations in the approach used to address anatomical variations in the location of the great vessel bifurcation in the region of the L4-L5 intervertebral disc space when performing laparoscopic interbody fusion procedures. SUMMARY OF BACKGROUND DATA: Recent interest in laparoscopic spine surgery using threaded cages has resulted in questions regarding the ability to safely access the L4-L5 disc using this approach. The laparoscopic transperitoneal approach to L5-S1 is below the bifurcation of the great vessels, thus requiring minimal mobilization of the iliac vessels. However, the transperitoneal approach to L4-L5 may be complicated by the bifurcation of the great vessels anterior to this disc space. Difficulty in placing two cages may occur if the vessels cannot be adequately mobilized. METHODS: Data were collected for the consecutive series of the first 58 patients (40 males, 18 females; mean age 42.5 years) undergoing laparoscopic anterior lumbar interbody fusion (ALIF) at the L4-L5 level using BAK cages. Operative notes were reviewed to determine variations in the operative approach. In particular, it was recorded if the L4-L5 disc was accessed above, or below the bifurcation of the aorta and the vena cava, or between these structures. The blood loss, operative time, and length of hospitalization were compared with respect to approach variation. RESULTS: In 30 patients, the L4-L5 disc was accessed above the great vessel bifurcation, in 18 patients below the bifurcation, and in the remaining 10 patients, by passing between the vessels. There were no statistically significant differences in the operative time, blood loss, or length of hospitalization with respect to the approach used. Three patients were converted to open procedures as a result of bleeding from segmental veins. None required transfusions and there were no postoperative sequelae. In two patients, successful endoscopic repair of segmental vein avulsion from the vena cava was performed using endoscopic loop ligatures. One patient had a secondary procedure to remove a cage that was causingnerve irritation, and one patient reported retrograde ejaculation after a two level fusion. Another patient, in whom a posterior herniation was removed, later presented with a cerebrospinal fluid leak. Most of the operative complications occurred early in the series. CONCLUSIONS: Laparoscopic transperitoneal approach to L4-L5 for insertion of threaded fusion cages is feasible. The laparoscopic L4-L5 procedure can be accomplished with few complications, provided a dedicated team of collaborative surgeons with experience in laparoscopic spine techniques is employed. Variations in vascular anatomy did not prevent successful insertion of two threaded fusion cages.

Adult↗

PubMed2005

Spatial mapping of the brachial plexus using three-dimensional ultrasound.

Imaging of the brachial plexus with MRI and standard two-dimensional (2D) ultrasound has been reported, and 2D ultrasound-guided regional anaesthetic block is an established technique. The aim of this study was to map the orientation of the brachial plexus in relation to the first rib, carotid and subclavian arteries, using three-dimensional (3D) ultrasound. A free-hand optically tracked 3D ultrasound system was used with a 12 MHz transducer. 10 healthy volunteers underwent 3D ultrasound of the neck. From the 3D ultrasound data sets, the outlines of the brachial plexus, subclavian artery and first rib were manually segmented. A surface was interpolated from the series of outlines to produce a spatially orientated 3D reconstruction of the brachial plexus. The brachial plexus could be mapped in all volunteers, although a variation in image resolution between individuals existed. Anatomical variations were demonstrated between the 10 volunteers; the most notable and clinically relevant was the alignment of the plexus divisions. 3D reconstructions illustrated the plexus, changing its orientation from a vertical alignment in the interscalene region to a more horizontal alignment in the supraclavicular fossa. Spatial mapping of the brachial plexus is possible with 3D ultrasound using the subclavian artery and first rib as landmarks. There is a deviation from the conventionally described anatomy and this may have implications for the administration of regional anaesthesia.

Adult↗

PubMed2006

Unique variation of digastric muscle: a confusing landmark for head and neck surgeons.

An anatomical variation of the left digastric muscle was found during the functional neck dissection of a patient with laryngeal carcinoma. This variant of the digastric muscle had three bellies including an accessory posterior belly. The anterior and posterior bellies had normal origin and course and were linked to each other by an intermediate tendon, whereas the accessory posterior belly took its origin from the mastoid notch of the temporal bone, together with the original posterior belly, sloped inferiorly and anteriorly, and inserted to the lateral border of the strap muscles by an evident tendon. This unique variation has not been reported in the literature. Presentation of this variation will guide surgical procedures, as well as anatomical dissections and medical imaging of the neck.

Accessory Nerve↗

PubMed2000

Congenital diaphragmatic hernia in neonates: variations in umbilical catheter and enteric tube position.

PURPOSE: To evaluate anatomic variations of support apparatus position on radiographs obtained in neonates with congenital diaphragmatic hernia (CDH). MATERIALS AND METHODS: The authors evaluated radiographs obtained in 71 neonates with CDH to determine whether nasogastric tubes, umbilical venous catheters, and umbilical arterial catheters deviated from their expected anatomic course. The relationship between deviation patterns and hernia contents was evaluated. RESULTS: Sixty-eight neonates-54 with left-sided CDH and 14 with right-sided CDH-had a nasogastric tube. The tubes in 21 patients with left-sided CDH had a normal anatomic course at radiography. Nineteen of these patients did not have stomach in the hernia. In 13 patients, the tip of the nasogastric tube was lodged at the esophagogastric junction. In 17 patients, the tube was in the left hemithorax. In all 30 of these patients, the stomach was within the CDH. All nasogastric tubes in the 14 patients with right-sided CDH had leftward deviation. Thirty-seven patients-27 with left-sided CDH and 10 with right-sided CDH-had umbilical venous catheters. The catheters in 12 patients with left-sided CDH had apex leftward convexity. The umbilical venous catheter in eight patients with right-sided CDH had rightward shift; all eight patients had liver herniation. CONCLUSION: The positions of nasogastric tubes and umbilical venous catheters vary in several predictable patterns in neonates with CDH. Knowledge of these variations may be helpful for supporting the diagnosis of CDH in unclear cases and thus avoiding unnecessary apparatus adjustments, and for predicting hernia contents.

Catheterization, Peripheral↗

PubMed2005

The variations of the sensory branches of the superficial peroneal nerve course and its clinical importance.

BACKGROUND: Although the sensory branches of the superficial peroneal nerve (SPN) have different anatomical variations that are of clinical importance, little is known about their anatomic courses, branching patterns, or relationships to palpable osseous landmarks.(1,3) A detailed knowledge is necessary for surgical exposures about the foot and ankle, arthroscopic procedures, ankle block anesthesia, and SPN block for leg venography. METHODS: Thirty lower cadaver limbs were dissected to assess the anatomic properties and the variations of the sensory branches of the SPN. RESULTS: Three distinct branch patterns were determined. In Type 1 (63.3%), the nerve penetrated the crural fascia 80.15 +/- 17.80 mm proximal to the intermalleolar line and then divided into the intermediate dorsal cutaneous nerve (IDCN) and the medial dorsal cutaneous nerve (MDCN) (classic type). In Type 2 (26.7%), the IDCN and MDCN arose independently from the SPN. In Type 3 (10%), the SPN penetrated the crural fascia 101.14 +/- 70.27 mm proximal to the intermalleolar line as a single branch. This single branch had a similar course to the MDCN. Measurements in this study were obtained from palpable bony reference landmarks. CONCLUSION: Detailed knowledge about the SPN, IDCN, and the MDCN may decrease the damage to these nerves during operative procedures near the foot and ankle.

Arthroscopy↗

PubMed1977

Optic nerve decompression. A clinical pathologic study.

Decompression of the perioptic meninges for intractable chronic papilledema was done in a patient with a right parietal temporal glioblastoma multiforme. The patient died 39 days postoperatively. Histologic study of the optic nerves indicated fistulas in the dura compatible with cerebrospinal fluid (CSF) egress and maintenance of a normal subarachnoid space around the nerve. Two additional patients with unilateral optic nerve decompression producing bilateral resolution of papilledema were studied. We contend that egress of CSF was the principle mode of action in these three cases. How long the dural fistula remains patent is unknown. Reports in the literature show considerable variation in the effects of optic nerve decompression. Anatomic variation of the intracanalicular subarachnoid space together with differences in underlying pathologic condition, surgical technique, and patient response may explain discrepancies among the results reported.

Adolescent↗

PubMed2002

Thoracic, lumbar, and sacral spine anatomy for endoscopic surgery.

We discuss the anatomy of the thoracic, lumbar, and sacral levels of the spinal cord. Given the nature of endoscopic surgery, it is recommended that the surgeon have thorough knowledge not only of the bony architecture but also of important visceral and other soft tissue structures. It is essential to understand the normal anatomy to recognize the abnormal and anatomic variations. We present the so-called normal anatomic configurations and illustrate how these structures vary at the different levels of the spinal column.

Blood Vessels↗

PubMed2004

Surgical classification of variations in the anatomy of the sigmoid sinus.

OBJECTIVE: Analyze the variability of anatomic relations between the sigmoid sinus and other surgical landmarks within the mastoid cavity to establish a classification of sinus location to facilitate surgical planning. STUDY DESIGN: A descriptive study of surgical landmarks using 96 temporal bones from the Temporal Bone Laboratory at the Department of Otorhinolaryngology, Valle University at Cali, Colombia. METHODS: A dissection simulating a canal wall-up mastoidectomy extended to include exposure of the facial recess, epitympanum, and sigmoid sinus was performed on 96 adult disease-free temporal bones. Seven standard measurements were taken on each bone between the sigmoid sinus and other structures in the mastoid cavity. All data were analyzed using Epi-Info 2000. RESULTS: This parametric study was consistent with three classes of anatomic variations in the location of the sigmoid sinus (type 1, type 2, and type 3) based on a Gaussian distribution of the seven variables. CONCLUSIONS: Variability in the anatomic location of the sigmoid sinus in the mastoid cavity is common and has surgical relevance. SIGNIFICANCE: This classification will help to rapidly identify the sigmoid sinus relationship within the mastoid cavity and to use the sigmoid sinus as a landmark during ear surgery in those cases in which traditional landmarks, such as the posterior auditory canal wall or the semicircular canals, are destroyed by a pathologic process.

Humans↗

PubMed2005

Multiplanar reconstructions of helical computed tomography in planning of atlanto-axial transarticular fixation.

The objective of this study was to determine atlanto-axial bone morphometric measurements related to screw transarticular fixation technique. One hundred helical computerized tomography (helical CT) scans with volumetric acquisition, including the first and the second cervical vertebrae, were studied. The screw insertion axis according to the Magerl technique for C1-C2 transarticular fixation was the referential to select the correct oblique axial and oblique parasagittal planes obtained with multiplanar reconstruction (MPR) on helical CT. The selected measured parameters on each side of the vertebrae were C2 interarticular isthmus height and width, optimal screw length, optimal screw trajectory sagittal and axial angles, and the distance between the ideal screw trajectory and the vertebral artery groove. C2 interarticular isthmus height measured 7.75+/-1.27 mm, C2 interarticular isthmus width 7.94+/-1.72 mm, optimal screw length 39.03+/-2.81 mm, optimal screw trajectory sagittal angle 57.54+/-5.28 degrees , optimal screw trajectory medial angle 7.90+/-4.05 degrees. Isthmus narrowing under 5 mm (height and/or width) was seen in 5% of cases. In 30% of cases reconstructed parasagittal images showed the vertebral artery groove. In those cases, the distance between the vertebral artery groove and the ideal screw path was measured. This distance measured under 2.5 mm in 7% of C2 articular masses. A classification of C2 articular mass morfology was proposed. The C2 articular masses without anatomic variations predisposing to vertebral artery injury were considered type I. The C2 articular masses potentially associated with vascular injury (12%) were classified as type II. Potential risk was identified at the C2 isthmus only (3%), at the anterior portion of C2 articular mass only (7%) or at both regions (2%). According to selected criteria 18% of patients would have at least one side C2 articular mass with potential risk for the vertebral artery. In 6% of patients the potential risk was identified bilaterally. There is a great variation in the maximum and minimum values of the anatomic measurements. Therefore preoperative CT scans are very important to identify type II cases, such that the surgeon may preoperatively define the bony anatomy trough which the screws will pass.

Atlanto-Axial Joint↗

PubMed1995

Normal variations of the temporal bone on high-resolution CT: their incidence and clinical significance.

We evaluated normal variations of the temporal bone on high-resolution computed tomograms (HR-CTs) and investigated their incidence. HR-CTs of the temporal bones of 325 patients were retrospectively reviewed. Six groups of variants, which were considered important for presurgical planning, were evaluated on HR-CTs. These included: (1) an incomplete bony covering of a high-positioned jugular bulb; (2) severe asymmetry of the jugular foramen; (3) an anteriorly located sigmoid sinus; (4) a deep sinus tympani; (5) a large internal auditory canal; and (6) a large cochlear aqueduct. The frequency of the variations were as follows: (1) 2.4%; (2) 4.0%; (3) 1.6%; (4) 5.9%; (5) 2.3%; and (6) 3.0%. Bilateral involvement with variation (4), (5) and (6) was frequently seen. Normal anatomical variations of the temporal bone are therefore not rare and awareness of the possible variants is necessary before surgery of the inner ear, middle ear and posterior fossa.

Adolescent↗

PubMed1999

Report of a rare human variation: the superficial ulnar artery arising from the axillary artery.

A rare variation of the ulnar artery is presented on routine anatomical dissection in one male cadaver. The superficial ulnar artery was found to originate from the axillary artery. The free forearm flap is increasingly popular among plastic surgeons. As a result of this case, and a review of the literature to gain further knowledge of anatomical variations, it is advised that more attention should be paid clinically to this artery to prevent its injury.

Anatomy, Artistic↗

PubMed1993

Hepatic arterial variations and liver-related diseases of 100 consecutive donors.

We prospectively studied anatomical variations and diseases of the liver in 100 consecutive donor operations during a period of 1 year. The "normal" arterial anatomy with a single hepatic artery (HA) from the celiac trunk was seen in 76% of all cases. Seven of twelve different major variations of the HA may be considered as "rare", one of which cannot be found in the earlier literature. During harvesting, 6% of the livers were discarded, 3% on the basis of infection and 1% because of a polycystic disease. Two cases were rejected as the liver was found to be severely hypoperfused or hypoxic in an otherwise stable donor. Severe steatosis was macroscopically and histologically diagnosed in 3% of the cases, and in three donors a benign tumour was found in the liver or in the gall bladder. Two primarily nonfunctioning livers in the present series of 94 recipient operations were retrieved from this group of severely steatotic livers. As the donor liver was totally "normal" in only 2 out of 3 of the cases, the present study underlines the importance of searching for extremely variable anomalies of the HA and for liver-related diseases during organ harvesting.

Hepatic Artery↗

PubMed1988

The lienorenal ligament and the tail of the pancreas: a surgical anatomical study.

Only brief descriptions of the lienorenal ligament and the anatomical relationship between the tail of the pancreas and the hilus of the spleen have been reported in the literature. The anatomical variations in this region are of significant surgical importance. The lienorenal ligament was studied in 37 anatomical specimens. A classification of its variations is presented, and clinical-surgical applications are discussed.

Aged↗

PubMed1983

[Variations in the hepatic artery in the surgery of portal hypertension].

The effect of anatomical variations of the hepatic artery on the performance of the anastomosis was assessed during 390 portacaval shunt operations as well as the degree to which technical difficulties could be anticipated from preoperative arteriography. Variations were detected in 25 p. cent of 130 patients examined by angiography but were confirmed during portal vein dissection in only 11 p. cent of cases. Technical difficulties due to hepatic artery variations were encountered in only 2 p. cent of the 390 anastomosis. Accidental section of a right hepatic artery occurred once only, and this before the routine use of angiography. Treatment was by aortohepatic by-pass using a saphenous graft. Portacaval anastomosis can be conducted in the presence of an hepatic artery variation bat technical difficulties cannot be predicted by preoperative digestive angiography.

Adolescent↗

PubMed1986

Technical difficulties of selective venous blood sampling in the differential diagnosis of female hyperandrogenism.

To determine glandular steroid release of adrenals and ovaries in female hyperandrogenism, a standardized method for percutaneous transfemoral venous blood sampling was developed. In eight volunteers and 67 patients, catheterization was performed during the early follicular phase (days 3-7; between 8 and 10 a.m.) to reduce interference from cyclic and circadian variations of secretion. Serial samplings reduced the episodic effluent changes. Anatomical variations and collateral flow as well as stress effects and the dosage of contrast media were studied. During catheterization, peripheral cortisol levels did not differ significantly from control groups. Collaterals had no effect on hormone levels. Contrast media increased cortisol effluent levels only when they were sampled following venography. Four-vessel venous sampling was found to be indicated if peripheral testosterone was more than 1.5 ng/ml and/or dehydroepiandrosterone sulfate more than 6,700 ng/ml. If an ovarian (adrenal)/peripheral gradient of testosterone exceeded 2.7 ng/ml, surgical intervention for tumor removal at the site of hormone excess was felt to be necessary.

Adolescent↗

PubMed2002

McBurney's point: are we missing it?

A prospective study of 100 post-evacuation barium enemas was done. Films were centered at McBurney's point, with an opaque skin marker at that point. Analysis of these revealed that in only one case (1%) was the base of the appendix at McBurney's point. In 67% it was cephalic and in 32% it was caudal to this point. The limitations of McBurney's point as an anatomical landmark should be recognized. This needs to be highlighted in teaching anatomy, especially to surgical trainees. Planning and choice of surgical incisions should be based on an understanding of these anatomical variations since McBurney's original description was clinical rather than anatomical.

Adolescent↗

PubMed1996

Microsurgical anatomy of the lateral approach to extraforaminal lumbar disc herniations.

OBJECTIVE: During the "lateral" approach to extraforaminal lumbar disc herniations, the surgeon may be confronted with considerable variations in anatomy, making this approach extremely difficult in some patients. An anatomic study, therefore, was undertaken to examine the bony boundaries of the operative target, the medial intertransverse space. METHODS: In 31 lumbar spine specimens taken from cadavers of people who had been between 30 and 93 years old at death, the relevant distances and proportions of the operative window were measured at the levels L1-L2 to L5-S1. RESULTS: Measurements revealed that the operative window in a systematic fashion becomes progressively smaller as the approach moves from L1-L2 toward L5-S1: 1) from L1 to L5, the medial boundary, the isthmus laminae, gradually extends farther laterally and eventually covers the waist of the respective vertebral body; 2) the lower boundary, the facet joint, gradually overlaps the disc space in an upward and lateral direction; 3) the upper boundary, the transverse process, gradually moves downward. Anatomic variations and abnormalities are found particularly often at the L5-S1 level. CONCLUSION: The anatomic findings led to important conclusions regarding the microsurgical approach to extraforaminal lumbar disc herniations; at levels L1-L2 to L3-L4, the midline approach with lateral retraction of the paraspinal muscles allows for efficient exposure of the lateral neural foramen and avoidance of trauma to the facet joint. Often at level L4-L5, and nearly always at level L5-S1, a tangential route through a paramedian transmuscular approach offers many advantages.

Adult↗

PubMed2006

Diffusion indices on magnetic resonance imaging and neuropsychological performance in amnestic mild cognitive impairment.

BACKGROUND: Magnetic resonance diffusion tensor imaging (DTI) shows promise in the early detection of microstructural pathophysiological changes in the brain. OBJECTIVES: To measure microstructural differences in the brains of participants with amnestic mild cognitive impairment (MCI) compared with an age-matched control group using an optimised DTI technique with fully automated image analysis tools and to investigate the correlation between diffusivity measurements and neuropsychological performance scores across groups. METHODS: 34 participants (17 participants with MCI, 17 healthy elderly adults) underwent magnetic resonance imaging (MRI)-based DTI. To control for the effects of anatomical variation, diffusion images of all participants were registered to standard anatomical space. Significant statistical differences in diffusivity measurements between the two groups were determined on a pixel-by-pixel basis using gaussian random field theory. RESULTS: Significantly raised mean diffusivity measurements (p<0.001) were observed in the left and right entorhinal cortices (BA28), posterior occipital-parietal cortex (BA18 and BA19), right parietal supramarginal gyrus (BA40) and right frontal precentral gyri (BA4 and BA6) in participants with MCI. With respect to fractional anisotropy, participants with MCI had significantly reduced measurements (p<0.001) in the limbic parahippocampal subgyral white matter, right thalamus and left posterior cingulate. Pearson's correlation coefficients calculated across all participants showed significant correlations between neuropsychological assessment scores and regional measurements of mean diffusivity and fractional anisotropy. CONCLUSIONS: DTI-based diffusivity measures may offer a sensitive method of detecting subtle microstructural brain changes associated with preclinical Alzheimer's disease.

Aged↗