Biomedical subjects

A S Suhardja

Publications and source records attributed to A S Suhardja.

3 recordsLinked to original sources

PubMed2001

Surgical exposure and resection of the vertical portion of the petrous internal carotid artery: anatomic study.

OBJECTIVE: The goals were to determine which surgical approaches, i.e., the preauricular subtemporal infratemporal fossa (PSI), postauricular transtemporal (PAT), and/or subtemporal middle fossa (SMF) approaches, provide optimal exposure of the anterior, posterior, medial, and lateral aspects of the vertical segment of the petrous internal carotid artery (VPCA) and to determine the length of the VPCA that can be resected before a vein graft is necessary. METHODS: Using 22 cadaveric specimens, we compared the length of exposure of the VPCA provided by the PSI, PAT, and SMF approaches. The segment of the VPCA that was exposed with each approach was measured in millimeters and expressed as a percentage of the total length of the VPCA. Resection of the VPCA in 1-mm increments was performed until a graft would be necessary; the total length of the resected segment was recorded in millimeters and was also expressed as a percentage of the total length of the VPCA. RESULTS: The PSI approach provided average exposures of 14.1 mm (95% of the total exposure possible) of the anterior aspect and 14.3 mm (96%) of the lateral aspect of the VPCA; resection of less than 2.3 mm (16%) of the VPCA could be repaired with an end-to-end anastomosis. The PAT approach provided average exposures of 10.5 mm (71 %) of the lateral aspect and 10.0 mm (76%) of the posterior aspect of the VPCA; resection of less than 2.8 mm of the VPCA could be repaired with an end-to-end anastomosis. The SMF approach provided average exposures of 6.1 mm (45%) of the anterior aspect and 5.4 mm (41 %) of the lateral aspect of the VPCA; resection of less than 2.4 mm (24%) of the VPCA could be repaired with an end-to-end anastomosis. CONCLUSION: Lesions on the anterior and lateral aspects of the VPCA can be fully exposed with the PSI approach or partially exposed with the less invasive SMF approach. Lesions on the posterior aspect of the artery are best exposed with the PAT approach. Lesions on the medial aspect of the VPCA cannot be exposed unless the VPCA is mobilized in the PSI approach. Resection of less than approximately 2.5 mm (20%) can be repaired with an end-to-end anastomosis, regardless of the approach used.

Carotid Artery, Internal↗

PubMed2000

Craniotomy revisited: techniques for improved access and reconstruction.

OBJECTIVE: To describe simple modifications of the technique of opening and closure of the craniotomy to improve basal exposure and reconstruction. METHODS: The modifications involve: a) additional soft-tissue dissection which is carried downward to the base of the ear and to the orbital rim, exposing the orbital rim and malar eminence without removing the bone; b) cutting the bone flap so that 'bridges' of bone remain that help to stabilize the flap when it is returned to the cranium at the end of the operation; c) the wedging of bone chips between the bone flap and native cranium at the time the bone is being reaffixed so as to provide firm stability by diminishing movement of the bone flap; d) the use of bone dust and bone chips mixed with the patient's blood to seal and bridge the gap between the bone flap and the native bone; e) reattachment of the temporalis muscle with the bone flap sutures. An 'inlay' technique of duraplasty is also described. RESULTS AND CONCLUSION: These simple modifications of craniotomy provide better basal exposure and reconstruction with little additional operating time at no additional cost.

Craniotomy↗

PubMed1999

Molecular pathogenesis of pituitary adenomas: a review.

Modern theory of tumorigenesis suggests that genetic alterations may play a role in the initiation and promotion of pituitary adenomas. Gsp and MEN-1 genes play a role in the initiation event, while p53, ras, Rb and nm23 genes play some role in the progression of the tumor. Gsp gene, that may play an important role in 40% of GH-producing tumor, activation of 10% of non-functioning tumors and 6% of corticotroph adenomas, produces cAMP, which stimulates cyclin D1 and D3 which later produce cdk2 and cdk4 respectively, and stimulates cell progression from G1 to S phase. cAMP also induces ras gene, which inhibits binding of pRb with E2F that is necessary to prevent action of E2F in accelerating cell cycle. MEN-1 gene, although found in some sporadic tumors, is more likely associated with familial adenoma. p53, Ras, Rb, nm23 and c-myc genes play some role in the promotion of tumors especially toward their aggressive variant. p53 gene, which is found in up to 60% of ACTH producing adenomas, through action of p21 inhibits progression of cell cycle from G1 to S phase, by inhibiting the action of cyclin D3 on cdk4. Ras oncogene, in cooperation with c-myc gene, prevents the binding of pRb with E2F, which is necessary for preventing progression cell cycle, resulting in progression of cell cycle from G1 to S phase. Nm23 gene inhibits the action of cyclin B and arrests the cell in G2 phase. Further studies will not only be helpful in understanding the genetic pathogenesis and prognosis of pituitary tumors, but also in developing a novel treatment for patients with pituitary adenomas.

Adenoma↗