Non-assisted versus neuro-navigated and XperCT-guided external ventricular catheter placement: a comparative cadaver study.

BACKGROUND AND PURPOSE: Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision. METHODS: Ten cadaver heads were prepared by opening large bone windows centered on Kocher's points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared. RESULTS: Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2 % (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4 mm versus 9.6 ± 7.2 mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06 min. to 7.3 ± 3.6 min. (p < 0.001). The X-ray exposure for XCT was 32.23 mSv, but could be reduced to 13.9 mSv if patients were initially imaged in the hybrid-operating suite. No supplementary radiation exposure is needed for NN if patients are imaged according to a navigation protocol initially. CONCLUSION: This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning.

Focal compression of the upper left thoracic intersegmental arteries as a potential cause of spinal cord ischemia.

BACKGROUND AND PURPOSE: This study was prompted by recurrent angiographic observations of focal stenoses involving the proximal segment of the left upper thoracic intersegmental arteries, a few centimeters distal to their origin. The purpose was to investigate the nature and prevalence of this anomaly. MATERIALS AND METHODS: The existence of non-ostial thoracic intersegmental artery stenoses was evaluated in 50 angiograms; the contribution of stenosed branches to the anterior spinal artery was recorded. Angiograms performed in 3 patients with right-sided aortas were also reviewed. The topographic relationships of the upper thoracic intersegmental artery with surrounding structures were investigated in 3 cadavers. RESULTS: Thirty-seven non-ostial stenoses were found in 26 patients (52%), predominantly on the left side (92%), between T3 and T8, most frequently at T4 and T5 (54%). Severe lesions were observed in 10% of cases. Patients with stenoses had fewer detectable anterior radiculomedullary arteries between T3 and T5 (35% versus 54%). Upper intersegmental artery stenoses, documented on the left side of all 3 specimens, appeared to be caused by the recurrent path of these intersegmental arteries related to the leftward position of the thoracic aorta, and by their course around reinforced paramedian longitudinal strands of the endothoracic fascia. CONCLUSIONS: Upper thoracic intersegmental artery stenoses are frequent. They result from the leftward deviation of the descending aorta and the existence of a fixed point along the course of the intersegmental arteries related to the endothoracic fascia. Because contributors to the spinal vascularization often originate at similar levels, these stenoses may play a role in the susceptibility of the upper and midthoracic spinal cord to ischemia.

Injury to the axillary nerve after reverse shoulder arthroplasty: an anatomical study.

BACKGROUND: Subclinical neurological lesions after reverse shoulder arthroplasty are frequent, mainly those involving the axillary nerve. One of the major reported risk factors is postoperative lengthening of the arm. The purpose of this study was to evaluate the anatomical relationship between the axillary nerve and prosthetic components after reverse shoulder arthroplasty. The study hypothesis was that inferior overhang of the glenosphere relative to glenoid could put this nerve at risk. MATERIAL AND METHODS: Eleven fresh frozen shoulder specimens were dissected after having undergone reverse shoulder arthroplasty using a classic deltopectoral approach. RESULTS: The mean distance from the inferior border of the glenoid to the inferior edge of the glenosphere was 6.0±4.3mm (range, 1.0 to 16.2mm). The axillary nerve was never closer than 15mm to the glenosphere. The main anterior branch of the axillary nerve was in close contact with the posterior metaphysis or humeral prosthetic implant. The mean distance between the nerve and the humeral implants was 5.2±2.1mm (range, 2.0 to 8.1mm). CONCLUSIONS: The proximity of the axillary nerve to the posterior metaphysis or humeral implants may be a risk factor for axillary nerve injury after reverse shoulder arthroplasty. CLINICAL RELEVANCE: This study quantifies the proximity of the axillary nerve to the implant after reverse shoulder arthroplasty. LEVEL OF EVIDENCE: Basic science study, cadaver study.

A critical inventory of preoperative skull replicas.

INTRODUCTION: Physical replicas of organs are used increasingly for preoperative planning. The quality of these models is generally accepted by surgeons. In view of the strong trend towards minimally invasive and personalised surgery, however, the aim of this investigation was to assess qualitatively the accuracy of such replicas, using skull models as an example. METHODS: Skull imaging was acquired for three cadavers by computed tomography using clinical routine parameters. After digital three-dimensional (3D) reconstruction, physical replicas were produced by 3D printing. The facsimilia were analysed systematically and compared with the best gold standard possible: the macerated skull itself. RESULTS: The skull models were far from anatomically accurate. Non-conforming rendering was observed in particular for foramina, sutures, notches, fissures, grooves, channels, tuberosities, thin-walled structures, sharp peaks and crests, and teeth. CONCLUSIONS: Surgeons should be aware that preoperative models may not yet render the exact anatomy of the patient under consideration and are advised to continue relying, in specific conditions, on their own analysis of the native computed tomography or magnetic resonance imaging.

3D for D3: role of imaging for right colectomy in a case with congenital superior mesenteric vein aneurysm and co-existing anomalous irrigation.

BACKGROUND: The D3 right colectomy for cancer requires dissection in the vicinity of the superior mesenteric vessels, which requires preoperative 3D imaging in these patients. CASE REPORT: We present a patient with a caecum adenocarcinoma cancer which underwent D3 resection of the right colon, preceded by pre-operative MDCT with 2D multiplanar reconstruction and 3D volume rendering. RESULTS: The dataset analysis revealed a rare congenital aneurysm of the superior mesenteric vein below the spleno-mesenteric confluence and a co-existing anomalous irrigation in the form of an ileo-mesenteric trunk. The surgical procedure was carried out as planned and the patient presents no signs of recurrence of the disease one year after the intervention. CONCLUSIONS: The case presented - with a rare and complicated vascular situs - illustrates particularly well that multimodal post-processing of the CT dataset for volume rendering allows proper assessment of the arrangement of pertinent blood vessels, and, consequently in the planning, setup and accomplishing the delicate operation, avoiding the surgical pitfalls and iatrogenic injuries.

Gastric varices without portal hypertension: role of left inferior vena cava?

A variant vascular anatomy was detected during regular analysis of multidetector computed tomography angiography of the abdomen in a 70 year-old female patient, referred to the department of surgery for laparoscopic right colectomy for colon cancer. The anomalous vessel was located left to the aorta, and was consistent with a persistent left inferior vena cava. It was connected by two retroaortic rootlets to the dorsal surface of the regular right inferior vena cava and had four notable tributaries - an anastomosis with the iliolumbar trunk, ovarian vein, renal vein and the inferior phrenic vein. In the upper abdomen, the left inferior vena cava took a tortuous course, passing at first between the spleen and the diaphragm, then curving below the inferior splenic border and terminating in an irregular network in the posterior region of gastric fundus and cardia, close to the splenic hilum, without supradiaphragmatic continuation. Despite this extraordinary termination, there were no signs of portal hypertension or data on previous occurrence of this condition.

Unilateral hypoplasia of the rostral end of the superior sagittal sinus.

BACKGROUND AND PURPOSE: Hypoplasia of the rostral third of the SSS is a well-known variant and constitutes the most frequent variation of the SSS after preferential drainage to one of the transverse sinuses. Our aim was to describe unilateral hypoplasia of the rostral end of the SSS. MATERIALS AND METHODS: CTA performed in 100 consecutive patients studied for conditions other than dural sinus thrombosis was reviewed for the presence of a unilateral or bilateral hypoplastic rostral SSS. Associated dural venous sinus anomalies were recorded as well. The angiographic anatomy of unilateral hypoplastic rostral SSS was illustrated by 2 cases further imaged with DSA. RESULTS: Unilateral hypoplastic rostral SSS was found in 7 patients (7%). In all cases, compensatory drainage occurred through a large superior frontal vein that joined the SSS in the region of the coronal suture. Three of the 7 patients with a unilateral hypoplastic rostral SSS had at least another dural venous sinus anomaly. Complete or bilateral hypoplastic rostral SSS was noted in 3 patients (3%). CONCLUSIONS: Unilateral hypoplastic rostral SSS is more than twice as frequent as bilateral hypoplastic rostral SSS. It is the most frequently encountered variation of the SSS. Knowledge of this anatomic variation is important to avoid diagnostic pitfalls and to avoid erroneously mistaking it for a thrombosis. Four types of variations of the rostral SSS may be identified: 1) classic anatomy with a fully developed rostral SSS; 2) duplication of the rostral SSS; 3) complete or bilateral hypoplastic rostral SSS; 4) unilateral hypoplastic rostral SSS. The 4 types of rostral SSS variations can be explained by studying the embryologic development of the SSS.

The effect of collateral ligament release on ankle dorsiflexion: an anatomical study.

BACKGROUND: Ankle stiffness is a common complication after ankle fracture, reconstructive surgery or total ankle replacement, and the usual limitation is in dorsiflexion. There are few articles in the literature concerning this frequent problem, and furthermore they are not recent and tend to be controversial. The purpose of this anatomical study was to evaluate and quantify the effect of ankle collateral ligament release on dorsiflexion, specifically the amount of increase in ankle dorsiflexion following section of the two ligaments most often implicated in ankle stiffness: the deep posterior tibiotalar ligament (dPTTaL, or posterior deep deltoid) and the posterior talofibular ligament (PTaFL). METHODS: We dissected 18 adult fresh cadaveric ankle joints, and with an electronic goniometer combined with an electronic dynamometer measured their mobility in dorsiflexion before and after transection of each ligament separately, and the two ligaments combined. RESULTS: The results showed a significant difference between the two groups of ankles with section of the dPTTaL resulting in a greater increase in ankle dorsiflexion than section of the PTaFL (mean 7.45° vs. 3.5°, respectively; p<0.001). Combined section of both ligaments improved the gain in ankle dorsiflexion more than isolated section of each ligament, but was not statistically significant (p=0.88). CONCLUSION: If after gastrocnemius recession or Achilles tendon lengthening persistent restriction remains in ankle dorsiflexion, the results of our study demonstrate that the next step should be release of the dPTTaL.

3D relations between right colon arteries and the superior mesenteric vein: a preliminary study with multidetector computed tomography.

BACKGROUND: 3-D relations between the ileocolic (ICA), right colic artery (RCA) with the superior mesenteric vein (SMV) have been described in cadavers. However, no data exists on preoperative evaluation of these relations. AIM: To define the length of crossing and 3-D position of the ICA and RCA to the SMV in patients undergoing multidetector computerized tomography (MDCT) angiography. METHODS: MDCT angiographies were analyzed with the aid of Osirix v.3.0.2. image processing application. All the datasets included arterial and venous phase, undergoing multimodal visualization: 2D multiplanar reconstruction with maximum intensity projection and 3D Volume rendering. The anatomical relations were analyzed in various planes (orthogonal and oblique), depending upon their particular course. When a clear spatial reference was achieved, the distance of the colic artery from their origin on the aorta to the right border of the SMV was measured, and its position noted. RESULTS: 50 MDCT were analyzed (29 male). RCA occurred in 27 patients (54.0%), 25 (92.6%) passed anterior to the SMV. Length of crossing was 22.7±8.1 (8.3-41.3) mm. The ICA occurred in 48 (96%) passing under the SMV in 38 (79.2%). Length of crossing 15.4±5.8 (14.0-26.6) mm. CONCLUSIONS: RCA occurs in 54% patients, passes over the SMV in 92.6% specimens and leaves a 22.7 mm stump. ICA passes under the SMV in most cases, leaving a 15.4 mm stump. These data could be of crucial importance to the surgeon facing laparoscopic right colectomy for cancer.

Kaposi's sarcoma after repeated surgical procedures in an immunocompetent patient: the lymphatic hypothesis.

A 63-year-old Swiss patient developed acquired nodules on his right palm after 3 localized surgeries, called 'needle fasciotomy', for Dupuytren's disease. Kaposi's sarcoma (KS) was diagnosed in a biopsy of a nodule. A positive immunolabeling and serology for human herpesvirus 8 has been found, but human immunodeficiency virus and hepatitis C identification remained negative. The nodules were limited to the surgically traumatized area. This first report of a nonimmunocompromised patient developing a KS after repeated surgeries in a unique peculiar localized area with a dense lymphatic network sustains the hypothesis that tissue alterations involving the lymphatic system could play a central role in the occurrence of KS.

Arteria lusoria: developmental anatomy, clinical, radiological and surgical aspects.

The left aortic arch with an aberrant right subclavian artery, or arteria lusoria, is the most common aortic arch anomaly, occuring in 0.5-2.5% of individuals. Four vessels arise sequentially from the aortic arch: the right common carotid artery, the left common carotid artery, the left subclavian artery and the aberrant right subclavian artery, which crosses upwards and to the right in the posterior mediastinum. It results from a disruption in the complex remodelling of the paired branchial arches, typically of the right dorsal aorta distal to the sixth cervical intersegmental artery. The diagnosis and differentiation of arch anomalies is based on findings at chest radiography in association with those at esophagography. It is usually asymptomatic. When symptomatic, it produces dysphagia lusoria or dyspnea and chronic coughing. Treatment is indicated for symptomatic relief of dysphagia lusoria and for prevention of complications due to aneurysmal dilatation.

Subfrontal endoscopic fenestration of lamina terminalis: an anatomical study.

Different surgical approaches to and through the lamina terminalis (LT) have been proposed to treat pathologies of the anterior third ventricle. Moreover, the opening of the LT is a standard adjunct in ruptured aneurysm surgery. However, the endoscopic anatomy and approach to the LT have not been extensively described. In the following study we performed an endoscopic subfrontal approach to the LT on 10 human cadaveric specimens through a supraorbital minicraniotomy. We discuss the endoscopic anatomy of the LT region and its fenestration through such an approach. The clinical potential use of this alternative third ventriculostomy is also pointed out.

Hybrid natural orifice transluminal endoscopic surgery (NOTES) for Roux-en-Y gastric bypass: an experimental surgical study in human cadavers.

BACKGROUND AND STUDY AIMS: The advantages of a hybrid natural orifice transluminal endoscopic surgery approach to Roux-en-Y gastric bypass (hNOTES-RYGBP) might include: easier access to the peritoneal cavity, reduced number of ports and related complications, improved cosmesis, and others. However, currently available conventional endoscopic and laparoscopic instruments might be unsuitable for complex surgical procedures using transluminal access. The aim of this study was to investigate the feasibility and limitations of a NOTES RYGBP. METHODS: hNOTES-RYGBP was performed in human cadavers. Pouch creation was achieved by needle-knife dissection using a transvaginal, flexible scope. Articulating linear staplers were placed transumbilically to transect the stomach. Measurements of the small bowel were accomplished intraluminally or with flexible and rigid graspers. New methods were tested to create the gastro-jejunal anastomosis. A linear laparoscopic stapler was used to form the jejuno-jejunal anastomosis. RESULTS: Stapler manipulation and anvil docking, bowel manipulation and measurement, and tissue dissection presented the main obstacles for hNOTES-RYGBP. Conventional instruments were too short for some transvaginal manipulations. The time to complete the procedure was 6 - 9 hours. It was feasible to perform a complete hNOTES-RYGBP in four out of seven cadavers. Two cadavers were unsuitable due to anatomical abnormalities or advanced decay. One procedure was terminated before completion because of time constraints. Combinations of flexible and rigid visualization and manipulation were helpful, especially for dissection and gastric pouch creation. CONCLUSIONS: Several factors made hNOTES-RYGBP very challenging and time-consuming. A lack of proper instrumentation resulting in insufficient tissue traction, countertraction, and instrument manipulation complicated several steps during the procedure. A combination of flexible with rigid endoscopic techniques offers specific advantages for components of this type of surgery. Changes in instrument design are required to improve more complex endosurgical procedures.

Optimizing electrode implantation in sacral nerve stimulation--an anatomical cadaver study controlled by a laparoscopic camera.

BACKGROUND AND AIM: Sacral nerve stimulation is the therapy of choice in patients with neurogenic faecal and urine incontinence, constipation and some pelvic pain syndromes. The aim of this study is to determine the best insertion angles of the electrode under laparoscopic visualization of the sacral nerves. MATERIALS AND METHODS: Five fresh cadaver pelvises were dissected through an anterior approach of the presacral space, exposing the ventral sacral roots. Needles and electrodes were inserted into the S3 foramen. Both right and left sides were used, with the traditional percutaneous procedure. The validation was done by a laparoscopic camera controlling the position of the needle and electrode on the nerve. The angles were assessed with a goniometer and were confirmed in two living patients. RESULTS: The mean angle of insertion in the sagittal plane was 62.9+/-3 degrees (range, 59-70). In the axial plane, the mean angle for the left side was 91.7+/-13.5 degrees (range, 80-110) and 83.2+/-7.7 degrees for the right side (range, 75-95). These angles resulted in the optimal placement of the leads along the S3 sacral root, in all these cases. CONCLUSIONS: This study allows direct visualization during the placement of the needle and electrode, thus permitting accurate calculations of the best angle of approach during the surgical procedure in sacral nerve stimulation. These objective findings attempt to standardize this technique, which is often performed with the aid of intra-operative fluoroscopy but still leaving a lot to chance. These insertion angles should help to find more consistent and reproducible results and thus improved outcome in patients.

The risk of injury to neurovascular structures from distal locking screws of the Unreamed Humeral Nail (UHN): a cadaveric study.

When performing distal interlocking of an intramedullary humeral nail, there is risk of iatrogenic injuring to the neurovascular structures. Our cadaveric study with frozen sections through the distal humerus presents the anatomic relationship of the different neurovascular bundles and the trajectories used for the implantation of the three distal interlocking screws of the AO-UHN. The middle lateromedial pin was in direct contact with the radial nerve in 3 out of 10 cases, with the ulnar nerve in 3 out of 10 cases and with the brachial artery in 1 out of 10 cases. We recommend using only the two anteroposterior screws for distal interlocking, avoiding the lateromedial locking option. If this lateromedial locking screw is needed to gain adequate stability, it should be introduced under visual control.

Developmental anatomy of the distal vertebral artery in relationship to variants of the posterior and lateral spinal arterial systems.

BACKGROUND AND PURPOSE: A certain number of anatomic variants involving the distal vertebral artery (VA) are explained by variations in size and connection of the lateral spinal artery (LSA). This study examined the possible role of another branch of the VA, the posterior spinal artery (PSA), in the development of similar vascular variations. MATERIALS AND METHODS: Four types of variations in the distal VA, including the C1 and C2 origins of the posterior inferior cerebellar artery (PICA), the duplication of the distal VA, and the aberrant course of the distal VA, are illustrated by 9 angiographic observations. RESULTS: For each type of VA variant listed above, examples resulting from variations in size and connection of the LSA and PSA could be matched. CONCLUSION: Variation in size and connection of the PSA is at the origin of a set of anatomic variations of the distal VA similar, but not identical, to the vascular variants linked to the LSA.

Vascular invasion in pancreatic cancer: evaluation of endoscopic ultrasonography, computed tomography, ultrasonography, and angiography.

PRINCIPLES: Current methods for detecting vascular invasion in pancreatic cancer can be inaccurate, invasive, and expensive. The aim of this study is to assess the value of current imaging modalities in determining vascular invasion by pancreatic cancer. METHODS: The results of Endoscopic Ultrasonography (EUS), Computed Tomography (CT), Ultrasonography (US), and Angiography performed in 170 patients, suffering from pancreatic cancer, were retrospectively studied and correlated with intra-operative findings and surgical anatomopathological diagnosis after resection. We assessed sensitivity, specificity, positive and negative predictive values, and accuracy for detecting vascular invasion. RESULTS: EUS turned out to be the most reliable imaging technique for detecting vascular invasion in pancreatic cancer, with a sensitivity of 55%, specificity of 90%, positive predictive value of 61.1%, negative predictive value of 87.5%, and accuracy of 82.2%. CT results were 39.4%, 90%, 52%, 84.4%, and 79.1% for the respective categories, with however, better results with multislice CT. The US results were 3.7% for the sensitivity, 96.3% for the specificity, 25% for the positive predictive value, 75.2% for the negative predictive value, and 73.4% for the accuracy. For angiography, the sensitivity, the specificity, the positive predictive value, the negative predictive value, and the accuracy were 52.6%, 72.3%, 43.5%, 79.1%, and 66.7% respectively. CONCLUSION: In this study, EUS was the most valuable imaging modality in assessing vascular invasion (especially for venous invasion) for pancreatic cancer, with an accuracy of more than 80%. A further prospective study should be carried out to evaluate the combination of imaging modalities for the detection of vascular involvement, especially with multi-slice CT which almost reached the performances obtained by EUS.

[Meaning of stylopharyngeal fascia in intraoral block techniques]. / Die Bedeutung der Fascia stylopharyngea bei intraoralen Blockadetechniken.

BACKGROUND: The almost unknown stylopharyngeal fascia may be one of the reasons for unsuccessful therapy of the trigeminal neuralgia by a transoral block of the superior ganglion of the sympathetic trunk. We investigated the anatomy of the fascia to show the efficiency of the block for this therapy. MATERIALS AND METHODS: 103 halves of human heads were investigated. The stylopharyngeal fascia was dissected by a lateral approach. We classified three groups. Group A was formed by fascias without perforation, group B by perforated fascias and group C by all halves without a developed fascia. RESULTS: We found a fully developed fascia in 86 cases. 13 halves had perforated fascias; in 4 cases the fascia was not developed. CONCLUSION: The stylopharyngeal fascia may inhibit the distribution of opoids into the infratemporal fossa associated with a consecutive block of the mandibular nerve and lower the rate of pain relief.

Anomalous intracranial drainage of the nasal mucosa: a vein of the foramen caecum?

The existence of the vein of the foramen caecum (VFC) in humans is still controversial. We present 2 patients with intracranial drainage of the nasal mucosa by a frontal cortical vein into a superior sagittal sinus, demonstrated by digital subtraction angiography. In both, the position of the intracranial passage was found to be slightly paramedian. An analogy to the VFC is made.