Biomedical subjects

Pushpa Deshmukh

Publications and source records attributed to Pushpa Deshmukh.

9 recordsLinked to original sources

PubMed2006

Multilayer image grid reconstruction technology: four-dimensional interactive image reconstruction of microsurgical neuroanatomic dissections.

OBJECTIVE: Cadaveric dissection is the gold standard for training physicians in various surgical specialties. However, limitations in acquiring and storing sufficient cadaveric material, recent pressures in training opportunities, and progress in digital image technology have led to advances in virtual or artificial visual means to augment surgical training. For training neurosurgeons, the appearance of reality is still crucial for learning anatomic structures and procedures. We developed a four-dimensional (including time) multilayer digital image reconstruction technology (MIGRT) that allows users to manipulate a "volumetric" set of photographic image data from exquisite cadaveric intracranial dissections and to navigate through stages of neurosurgical procedures as the dissection progresses. METHODS: A robotic microscope with two digital cameras was used to capture dissection images, usually in stereoscopic mode. A grid space was created to define positions at which images are captured. Images were acquired from identical angles at the same grid coordinates but at different stages of various dissections. RESULTS: Image data are reconstructed according to the sequence of acquisition into a multilayer image grid system by the MIGRT software. The single interactive, four-dimensional montage is viewable a on common computer platform. CONCLUSION: MIGRT uniquely focuses on capturing anatomic content that preserves natural appearances, including procedure, texture, and color, which is far superior and preferable to images and a reconstructed image environment based on artificial or animated concepts. MIGRT shows time-dependent changes in procedures, provides depth perception by stereoscopy or unique sequential motion, and allows simultaneous interactivity at each step of the procedure.

Brain↗

PubMed2006

An anatomical evaluation of the mini-supraorbital approach and comparison with standard craniotomies.

OBJECTIVE: To compare anatomically the surgical exposure provided by pterional (PT), orbitozygomatic (OZ), and minisupraorbital (SO) craniotomies. METHODS: Seven sides of six fixed cadaver heads injected with silicone were used. The mini-SO craniotomy followed by the PT and OZ approaches were performed sequentially. The bony flaps were attached with miniplates and screws, allowing easy conversion between the approaches. A frameless stereotactic device was used to calculate an area of surgical exposure and the angles of approach for six different anatomic targets. An image guidance system was used to demonstrate the limits of the surgical exposure for each technique. RESULTS: No significant differences were observed in the total area of surgical exposure when comparing the mini-SO (A = 1831.2 +/- 415.3 mm), PT (A = 1860.0 +/- 617.2 mm), and OZ approaches (A = 1843.3 +/- 358.1 mm; P > 0.05). Angular exposure was greater for the OZ and PT approaches than for the mini-SO approach, either in the vertical and horizontal axes, considering all of the six targets studied (P < 0.05). Except for the distal segment of the ipsilateral sylvian fissure, no practical differences in the limits of the exposure were detected. CONCLUSION: The mini-SO approach may offer a similar surgical working area compared with that provided by standard craniotomies and constitutes an excellent alternative to the OZ and PT craniotomies in selected patients. Selection should not be based primarily on the area to be exposed, but rather on the working angles that are anticipated to be required. The key point is to use the most adequate technique for a particular patient, rather than using a one-size-fits-all approach for all patients.

Cadaver↗

PubMed2006

The pterional-transsylvian approach: an analytical study.

OBJECTIVE: Splitting of the sylvian fissure (SF) improves exposure with the pterional (PT) approach. Traditionally, the choice of whether or not to split the SF and how far to open it has depended on the neurosurgeon's experience and preference rather than on quantifiable data. We undertook this study to evaluate the effects of progressive splitting of the SF on surgical exposure with the PT approach. METHODS: A PT craniotomy was performed on nine sides of cadaver heads. Splitting the SF was divided into four steps: 1) dissection of the basal cisterns, 2) dissection of the sphenoidal compartment, 3) dissection of the operculoinsular compartment to the anterior ascendant ramus, and 4) dissection progressing 2.0 cm distal to the anterior ascendant ramus. The degree of the retraction and the relative position of the brain retractors were kept constant. After each step, we used a computerized tracking system to measure the area of surgical exposure of the circle of Willis, the angles of approach to the carotid bifurcation, and the distance between the frontal lobe and skull base. RESULTS: Exposure of the circle of Willis, angles of approach to the carotid bifurcation, and linear distance between the frontal lobe and skull base all increased significantly as splitting of the SF progressed from Steps 1 to 2 and from Steps 2 to 3. There was no significant difference between Steps 3 and 4. CONCLUSION: Exposure of the basal cisterns and circle of Willis by the PT approach is optimized when dissection of the SF reaches the anterior ascendant ramus. Further splitting of the SF provides no additional gain.

Cadaver↗

PubMed2006

Quantitative analysis of the working area and angle of attack for the retrosigmoid, combined petrosal, and transcochlear approaches to the petroclival region.

OBJECT: The authors quantitatively assessed the working areas and angles of attack associated with retrosigmoid (RS), combined petrosal (CP), and transcochlear (TC) craniotomies. METHODS: Four silicone-injected cadaveric heads were bilaterally dissected using three approaches progressing from the least to the most extensive. Working areas were determined using the Optotrak 3020 system on the upper and middle thirds of the petroclivus and brainstem. Angles of attack were studied using the Elekta SurgiScope at the Dorello canal and the origin of the anterior inferior cerebellar artery (AICA). The TC approach provided significantly greater (p < 0.001) working areas at the petroclivus (755.6 +/- 130.1 mm2) and brainstem (399.3 +/- 68.2 mm2) than the CP (354.1 +/- 60.3 and 289.7 +/- 69.9 mm2) and RS approaches (292.4 +/- 59.9, 177.2 +/- 54.2 mm2, respectively). The brainstem working area associated with the CP approach was significantly larger (p < 0.001) than that associated with the RS route. There was no difference in the petroclival working area comparing the CP and RS approaches (p = 0.149). The horizontal and vertical angles of attack achieved using the TC approach were wider than those of the CP and RS at the Dorello canal and the origin of the AICA (p < 0.001). CONCLUSIONS: The CP approach offers a more extensive working area than the RS for lesions involving the anterolateral surface of the brainstem, but not for petroclival lesions. The TC approach provides the widest corridor, improving the working area and angle of attack to both areas, but hearing must be sacrificed and the facial nerve is at risk.

Brain Stem↗

PubMed2006

Anatomical and quantitative description of the transcavernous approach to interpeduncular and prepontine cisterns. Technical note.

OBJECT: The management of wide-necked, giant, or unsuccessfully coil-treated basilar apex aneurysms requires a wide exposure, for both working area and linear visualization of the basilar artery (BA). Cranial-based approaches, such as the transcavernous approach, have been proposed to deal with such aneurysms; whether abbreviated forms of this approach might provide similar exposure remains controversial. The authors examine this issue quantitatively. METHODS: Four alcohol-preserved cadaveric heads injected with pigmented silicone were prepared for bilateral dissection. After completing an orbitozygomatic craniotomy, the surgeons worked in a reverse direction, performing the transcavernous approach in five steps: 1) posterior clinoidectomy; 2) cavernous sinus opening; 3) anterior clinoidectomy; 4) cutting of the distal dural ring; and 5) cutting of the proximal dural ring. Performing the complete transcavernous approach significantly increased the working area and linear exposure of the BA compared with abbreviated forms of the approach (p < 0.05). Opening the roof of the cavernous sinus significantly increased the working area compared with posterior clinoidectomy alone (p = 0.014); however, additional gains in exposure required completing the transcavernous approach. Resection of the anterior clinoid process combined with opening of only the distal dural ring did not significantly increase the working area or linear exposure of the BA. CONCLUSIONS: The complete transcavernous approach significantly increases the working area and linear exposure of the BA compared with the more conservative forms of approach.

Basilar Artery↗

PubMed2005

Quantitative anatomic study of three surgical approaches to the anterior communicating artery complex.

OBJECTIVE: To compare the angles of approach and area of exposure to the anterior communicating artery (AComA) complex associated with pterional (PT), orbitopterional (OPT), and orbitozygomatic (OZ) craniotomies before and after gyrus rectus resection. METHODS: PT, OPT, and OZ craniotomies were performed on both sides of four heads, and the angles of approach and area of exposure to the AComA complex were measured before and after resection of the gyrus rectus. RESULTS: The vertical angle of approach increased significantly among the PT and OPT (P = 0.001), PT and OZ (P = 0.001), and OPT and OZ approaches (P = 0.005). The horizontal angle of approach was significantly larger between the PT to OPT (P = 0.001) and PT to OZ (P = 0.001) approaches but not between the OPT and OZ approaches (P = 0.757). After gyrus rectus resection, the vertical and horizontal angles of approach increased significantly for the PT approach but not for the OPT and OZ approaches. The area of exposure to the AComA complex increased progressively from the PT to OPT to OZ approach but did not reach statistical significance (P = 0.124). Resection of the gyrus rectus resulted in significant relative gains in the area of exposure for the PT (P = 0.01) and OPT (P = 0.04) approaches but not for the OZ approach (P = 0.88). CONCLUSION: The vertical and horizontal angles of approach to the AComA complex are significantly larger for the OPT and OZ approaches compared with the PT approach. Use of the OZ approach may decrease the need for frontal lobe retraction and resection of the gyrus rectus.

Anterior Cerebral Artery↗

PubMed2005

Microsurgical anatomy of the transcallosal anterior interforniceal approach to the third ventricle.

OBJECTIVE: We explored relevant regional microanatomy as it relates to the challenging anterior interforniceal (AIF) approach for removing hypothalamic hamartomas. METHODS: Five silicone-injected cadaveric heads were dissected by use of frameless stereotactic navigation to reveal microanatomy and extent of exposure through the transcallosal AIF approach. Distances between trajectories to the coronal suture and the genu of the corpus callosum (CC) and between the posterior border of the anterior commissure to the lower end of the rostrum of the CC and posterior border of the foramen of Monro were measured. RESULTS: The AIF approach provided adequate access to the anterior third ventricle and related structures (i.e., hypothalamus, infundibular recess, and mamillary bodies) through the corridor bounded by the anterior commissure anteriorly and the choroid plexus at the foramen of Monro posteriorly. The mean distances from the posterior trajectory to the coronal suture and the genu of the CC were 44.8 mm (range, 43.8-46.2 mm) and 14.88 mm (14.1-15.7 mm), respectively. The mean distance from the anterior trajectory posterior to the coronal suture was 4.66 mm (0-8.9 mm), and 32.6 mm (30.5-33.9 mm) to the genu of the CC. The mean length of callosotomy was 17.52 mm (16.2-19.1 mm). The mean distance between the posterior border of the anterior commissure and the lower end of the rostrum of the CC was 5.22 mm (4.6-5.6 mm), and 10.52 mm (9.7-11.5 mm) to the posterior border of the foramen of Monro. CONCLUSION: The technically safe AIF approach permitted limited interforniceal splitting, no major deep vein manipulation, and adequate visualization of the hypothalamus, infundibular recess, and mamillary bodies.

Cadaver↗

PubMed2005

Microsurgical anatomy and quantitative analysis of the transtemporal-transchoroidal fissure approach to the ambient cistern.

OBJECTIVE: Surgical approaches to ambient cistern lesions are complex. We investigated the microanatomy of the transtemporal-transchoroidal fissure approach to the ambient cistern with emphasis on exposure of the posterior cerebral artery. METHODS: Dissections were performed bilaterally in five silicone-injected cadaveric heads. Critical anatomic distances, specifically with reference to the P2 segment of posterior cerebral artery in relation to the inferior choroidal point and P2-P3 junction, were measured with digital calipers. Other landmarks (temporal lobe tip, points from the temporal base to the choroidal fissure) were included for quantitative analysis. RESULTS: The transtemporal-transchoroidal fissure approach provided adequate exposure of the ambient cistern, minimized temporal lobe retraction, and allowed assessment of regional microanatomy. The mean distance from the temporal base to the choroidal fissure measured 18.09 mm (range, 16.9-21.9 mm). The distances from the choroidal fissure to P2 varied at the coronal plane of the inferior choroidal point (mean, 6.96 mm; range, 3.6-12.0 mm) and the P2-P3 junction (mean, 6.02 mm; range, 4.3-6.9 mm), respectively. CONCLUSION: The transtemporal-transchoroidal fissure approach provides a corridor to the ambient cistern and P2-P3 junction while minimizing temporal lobe retraction and avoiding interruption of temporal lobe venous drainage. Because of widely variable vascular anatomy, access to posterior cerebral artery lesions using this approach requires preoperative imaging to identify the specific location of the P2-P3 junction.

Arachnoid↗

PubMed2002

Working area and angle of attack in three cranial base approaches: pterional, orbitozygomatic, and maxillary extension of the orbitozygomatic approach.

OBJECTIVE: This study was designed to quantify the operative exposure obtained in the pterional, orbitozygomatic, and modified orbitozygomatic with maxillary extension surgical approaches. METHODS: The pterional and orbitozygomatic approaches and a variation of the orbitozygomatic osteotomy that included an extra centimeter of bone resection in the inferior direction ("maxillary extension") were performed on cadaveric heads. For each surgical exposure, the working area was determined by using triangles defined with anatomic points. The "angle of attack" of the approaches for the same target point was determined with the use of a robotic microscope. RESULTS: The maximum allowable angle of attack was significantly greater with the orbitozygomatic approach (37.2 +/- 4.7 degrees) than that with the pterional approach (27.1 +/- 4.3 degrees) (P < 0.001). The angle of attack with the maxillary extension (42.0 +/- 4.9 degrees) was significantly greater than that with the orbitozygomatic approach (P < 0.001). The working areas were 281, 343, and 371 mm(2) for the pterional, orbitozygomatic, and maxillary extension approaches, respectively. The orbitozygomatic approach with maxillary extension had a significantly larger working area than the pterional approach (P = 0.011). CONCLUSION: Increments in bony removal open a wider angle in which to work more than they increase the actual amount of working area. Increasing the amount of bone removed by using an orbitozygomatic approach instead of a pterional approach converts a narrow space into a wide portal, allowing surgeons to work closer to the surgical target while decreasing the need for brain retraction. Extending the orbitozygomatic approach into the maxillary region also improves the exposure area and angle, but less significantly.

Cadaver↗