| Pheochromocytomas
are neuroendocrine tumors that produce, metabolize and secrete
catecholamines such as norepinephrine and epinephrine. In very rare
occasions hormonally active pheochromocytomas can produce and secrete
only dopamine as the only catecholamine. Predominance of dopamine in
this tumors and lack of production of other catecholamines is due to
deficiency in tumor cells of dopamine-B-hydroxylase, the enzyme that
converts dopamine into norepinephrine. Dopamine-producing
pheochromocytomas are usually found as extraadrenal paragangliomas.
Clinically patients harboring these tumors are normotensive. Most
patients are diagnosed after identifying the adrenal or extraadrenal
position of the tumor during incidental imaging or as the result of
symptoms caused by the space-occupying tumor. Due to lack of hormonally
associated symptoms these tumors can grow into large size. Tumors that
produce dopamine can be identified by high plasma or urine
concentrations of dopamine, or high plasma levels of free
methoxytyramine. The incidence of malignancy is higher in this type of
pheochromocytoma. Nausea, vomiting, flushing and orthostatic
hypotension are a few of the symptoms exhibited by these patients. MRI
is the imaging of choice to localize these tumors. Management consists
of resection of the tumor. Persistent elevation of blood pressure after
tumor resection have been documented. PET-Scan is more specific
than MIBG in localizing residual disease. References: 1- Minamiguchi N, Inui E, Nukui M: [A case of dopamine-secreting pheochromocytoma]. Hinyokika Kiyo. 45(12):831-3, 1999 2- Yasunari K, Kohno M, Minami M, Kano H, Ohhira M, Nakamura K, Yoshikawa J: A dopamine-secreting pheochromocytoma. J Cardiovasc Pharmacol. 36 Suppl 2:S75-7, 2000 3- Awada SH, Grisham A, Woods SE: Large dopamine-secreting pheochromocytoma: case report. South Med J. 96(9):914-7, 2003 4- Eisenhofer G, Goldstein DS, Sullivan P, Csako G, Brouwers FM, Lai EW, Adams KT, Pacak K: Biochemical and clinical manifestations of dopamine-producing paragangliomas: utility of plasma methoxytyramine. J Clin Endocrinol Metab. 90(4):2068-75, 2005 5- Tam V, Ng KF, Fung LM, Wong YY, Chan MH, Lam CW, Tam S, Lam CW: The importance of the interpretation of urine catecholamines is essential for the diagnosis and management of patient with dopamine-secreting paraganglioma. Ann Clin Biochem. 42(Pt 1):73-7, 2005 6- Foo SH, Chan SP, Ananda V, Rajasingam V: Dopamine-secreting phaeochromocytomas and paragangliomas: clinical features and management. Singapore Med J. 51(5):e89-93, 2010 7- Dubois LA, Gray DK: Dopamine-secreting pheochromocytomas: in search of a syndrome. World J Surg. 29(7):909-13, 2005 |
| Ventriculoperitoneal
(VP) shunt is the standard treatment for hydrocephalus in children and
adults. Malfunctioning VP shunts causing increase intracranial pressure
needs surgical revision. Such malfunctioning can occur due to
obstruction from peritoneal adhesion, multiple infections, ascites and
pseudocysts formation, or mechanical causes such as catheter fracture,
disconnection, migration and misplacement. VP shunt failure is common
with 25-40% occurring within the first year, and 50% by the second
year. Laparoscopy has an important role in initial VP shunt placement
and later revisions. Laparoscopy reduce the trauma to the abdominal
wall decreasing adhesion formation and optimizing visualization during
placement. With VP shunt failure laparoscopy can be both diagnostic and
therapeutic. While visualizing the entire abdominal cavity the causes
of failure can be identified, lysis of adhesions can be performed,
retrieval of disconnected shunt can be accomplished, flow of CSF fluid
can be observed and proper placement of the catheter can be obtained
The technique is safe with a very low morbidity rate. The use of
laparoscopy assisted VP shunt revision is advocated for patients with
multiple previous shunt revisions, prior abdominal surgery, previous
intraperitoneal infections, broken devices, obesity or CSF pseudocysts.
References: 1- Khosrovi H, Kaufman HH, Hrabovsky E, Bloomfield SM, Prabhu V, el-Kadi HA: Laparoscopic-assisted distal ventriculoperitoneal shunt placement. Surg Neurol. 49(2):127-34, 1998 2- Jackson CC, Chwals WJ, Frim DM: A single-incision laparoscopic technique for retrieval and replacement of disconnected ventriculoperitoneal shunt tubing found in the peritoneum.Pediatr Neurosurg. 36(4):175-7, 2002 3- Kirshtein B, Benifla M, Roy-Shapira A, Merkin V, Melamed I, Cohen Z, Cohen A: Laparoscopically guided distal ventriculoperitoneal shunt placement. Surg Laparosc Endosc Percutan Tech. 14(5):276-8, 2004 4- Bani A, Hassler WE: Laparoscopy-guided insertion of peritoneal catheters in ventriculoperitoneal shunt procedures: analysis of 39 children. Pediatr Neurosurg. 42(3):156-8, 2006 5- Yu S, Bensard DD, Partrick DA, Petty JK, Karrer FM, Hendrickson RJ: Laparoscopic guidance or revision of ventriculoperitoneal shunts in children.JSLS. 10(1):122-5, 2006 6- Johnson BW, Pimpalwar A: Laparoscopic-assisted placement of ventriculo-peritoneal shunt tips in children with multiple previous open abdominal ventriculo-peritoneal shunt surgeries. Eur J Pediatr Surg. 19(2):79-82, 2009 |
| Magnets
have been introduced in the armamentarium of laparoscopic surgery to
recapture the triangulation that is affordable by conventional
laparoscopy while decreasing the number and size of the abdominal
incisions utilized. Specialized magnetic grasper are inserted into the
peritoneal cavity through the port cannula and attached to
intraabdominal organs. These magnets are controlled by another external
magnet placed on top of the abdominal wall. The magnet grasper moves to
provide further traction on an organ without the additional need of
another port. With the magnet you can retract the liver, stomach, lung
tissue, gallbladder providing traction and facilitating exposure.
Magnet-assisted laparoscopy is safe and effective means of reducing the
number and size of abdominal incisions while improving exposure,
triangulation, and the ergonomics of the procedure. References: 1- Rothenberg SS, Shipman K, Yoder S: Experience with modified single-port laparoscopic procedures in children. J Laparoendosc Adv Surg Tech A. 19(5):695-8, 2009 2- Garey CL, Laituri CA, Ostlie DJ, Snyder CL, Andrews WS, Holcomb GW 3rd, St Peter SD: Single-incision laparoscopic surgery in children: initial single-center experience. J Pediatr Surg. 46(5):904-7, 2011 3- de Armas IA, Garcia I, Pimpalwar A: Laparoscopic single port surgery in children using Triport: our early experience. Pediatr Surg Int. 27(9):985-9, 2011 4- Dutta S: Early experience with single incision laparoscopic surgery: eliminating the scar from abdominal operations. J Pediatr Surg. 44(9):1741-5, 2009 5- Padilla BE, Dominguez G, Millan C, Martinez-Ferro M: The use of magnets with single-site umbilical laparoscopic surgery. Semin Pediatr Surg. 20(4):224-31, 2011 |
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