Lucio Godina (March 8, 1908 – November 24, 1936) and Simplicio Godina (March 8, 1908 - December 8, 1936) were pygopagus conjoined twins from the island of Samar in the Philippines.

At the age of 21 they married Natividad and Victorina Matos, who were identical twins. They performed in various sideshow acts, including in an orchestra on Coney Island and in dance with their wives.

After Lucio died of rheumatic fever in New York City, doctors operated to separate him from Simplicio. Simplicio survived the operation, but died shortly thereafter due to spinal meningitis.

Joseph Banda and Luka Banda (born January 23, 1997, in Lusaka, Zambia) are twin brothers who used to be conjoined. They were born joined at the back of the skull and faced in opposite directions. In 1997, Dr. Ben Carson led a team of 50 Zambian and South African specialists to separate the 11-month-old twins in a 22-hour operation. They did not share any organs, but shared intricate blood vessels that flowed into each other's brains. In 2001, the twins were fitted with artificial skulls to permanently close their heads, and are neurologically normal. In an interview, Dr. Carson stated about the operation:

They are residing in a low-cost/high-density area of Lusaka called Chilenje South.

Ladan and Laleh Bijani (in Persian: ) (January 17, 1974 – July 8, 2003) were Iranian conjoined twin sisters. They were joined at the head and died immediately after their complicated surgical separation. Coincidentally, the twins were born 100 years to the day of the deaths of Chang and Eng Bunker, also conjoined twins, famously known as the "original" Siamese twins.

The risk of awareness is reduced by avoidance of paralytics unless necessary; careful checking of drugs, doses and equipment; good monitoring, and careful vigilance during the case. The Isolated Forearm Technique (IFT) can be used to monitor consciousness; the technique involves applying a tourniquet to the patient's upper arm before the administration of muscle relaxants, so that the forearm can still be moved consciously. The technique is considered a reference standard by which other means of assessing consciousness can be assessed.

Only a few individuals who did not have fatal kidney and bladder complications are known to have survived beyond birth with this condition.

Sirenomelia, alternatively known as Mermaid syndrome, is a rare congenital deformity in which the legs are fused together, giving them the appearance of a mermaid's tail as the nickname suggests.

This condition is found in approximately one out of every 100,000 live births (about as rare as conjoined twins) and is usually fatal within a day or two of birth because of complications associated with abnormal kidney and urinary bladder development and function. More than half the cases of sirenomelia result in stillbirth and this condition is 100 times more likely to occur in identical twins than in single births or fraternal twins. It results from a failure of normal vascular supply from the lower aorta in utero. Maternal diabetes has been associated with caudal regression syndrome and sirenomelia, although a few sources question this association.

VACTERL-H is an expanded form of the VACTERL association that concludes that this diagnosis is a less severe form of sirenomelia. The disorder was formerly thought to be an extreme case of caudal regression syndrome; however, it was reclassified to be considered a separate condition.

Psychedelics such as LSD-25 and psilocybin-containing mushrooms demonstrate very rapid tachyphylaxis. In other words, one may be unable to 'trip' two days in a row. Some people are able to 'trip' by taking up to three times the dosage, yet some users may not be able to negate tachyphylaxis at all until a period of days has gone by.

In a patient fully withdrawn from opioids, going back to an intermittent schedule or maintenance dosing protocol, a fraction of the old tolerance level will rapidly develop, usually starting two days after therapy is resumed and, in general, leveling off after day 7. Whether this is caused directly by opioid receptors modified in the past or affecting a change in some metabolic set-point is unclear. Increasing the dose will usually restore efficacy; relatively rapid opioid rotation may also be of use if the increase in tolerance continues.

The complete or partial absence of the pectoralis muscle is the malformation that defines Poland Syndrome. It can be treated by inserting a custom implant designed by CAD (computer aided design). A 3D reconstruction of the patient's chest is performed from a medical scanner to design a virtual implant perfectly adapted to the anatomy of each one. The implant is made of medical silicone unbreakable rubber. This treatment is purely cosmetic and does not make up for the patient's imbalanced upper body strength.

The Poland syndrome malformations being morphological, correction by custom implant is a first-line treatment. This technique allows a wide variety of patients to be treated with good outcomes. Poland Syndrome can be associated with bones, subcutaneous and mammary atrophy: if the first, as for pectus excavatum, is successfully corrected by a custom implant, the others can require surgical intervention such as lipofilling or silicone breast implant, in a second operation.

Very rare causes of awareness include drug tolerance, or a tolerance induced by the interaction of other drugs. Some patients may be more resistant to the effects of anesthetics than others; factors such as younger age, obesity, tobacco smoking, or long-term use of certain drugs (alcohol, opiates, or amphetamines) may increase the anesthetic dose needed to produce unconsciousness but this is often used as an excuse for poor technique. There may be genetic variations that cause differences in how quickly patients clear anesthetics, and there may be differences in how the sexes react to anesthetics as well. In addition, anesthetic requirement is increased in persons with naturally red hair. Marked anxiety prior to the surgery can increase the amount of anesthesia required to prevent recall.

There are two less common types of McGillivray syndromes are: Metopic synostosis (trigonocephaly). The metopic suture runs from your baby's nose to the sagittal suture. Premature fusion gives the scalp a triangular appearance. Another one is Lambdoid synostosis (posterior plagiocephaly). This rare form of craniosynostosis involves the lambdoid suture, which runs across the skull near the back of the head. It may cause flattening of your baby's head on the affected side. A misshapen head doesn't always indicate craniosynostosis. For example, if the back of your baby's head appears flattened, it could be the result of birth trauma or your baby's spending too much time on his or her back. This condition is sometimes treated with a custom-fit helmet that helps mold your baby's head back into a normal position.

The surgery takes place under general anaesthesia and lasts less than 1 hour. The surgeon prepares the locus to the size of the implant after performing a 8-cm axillary incision and inserts the implant beneath the skin. The closure is made in 2 planes.

The implant will replace the pectoralis major muscle, thus enabling the thorax to be symmetrical and, in women, the breast as well. If necessary, especially in the case of women, a second operation will complement the result by the implantation of a breast implant and / or lipofilling.

Lipomodelling is progressively used in the correction of breast and chest wall deformities. In Poland syndrome, this technique appears to be a major advance that will probably revolutionize the treatment of severe cases. This is mainly due to its ability to achieve previously unachievable quality of reconstruction with minimal scaring.

First of all there is physical exam. Doctors examine baby’s head for abnormalities such as suture ridges and look the facial deformities. Also, they utilizes Computerized Tomography which scan of the baby’s skull. Fused sutures are identifiable by their absences. X-rays also may be used to measure precise dimensions of your baby's skull, using a technique called cephalometry.

Genetic testing. If your doctor suspects your baby's misshapen skull is caused by an underlying hereditary syndrome, genetic testing may help identify the syndrome. Genetic tests usually require a blood sample. Depending on what type of abnormality is suspected, your doctor may take a sample of your baby's hair, skin or other tissue, such as cells from the inside of the cheek. The sample is sent to a lab for analysis.

Pancreatic disorders are often accompanied by weakness and fatigue. The past Medical history may reveal previous disorders of the biliary tract or duodenum, abdominal trauma or surgery, and metabolic disorders such as diabetes mellitus. The medication history should be detailed and specifically include the use of thiazides, furosemide, estrogens, corticosteroids, sulfonamides, and opiates. Note a family history of pancreatic disorders. In the review of systems, obtain a complete description of any pain in the upper abdomen or epigastric area. Symptoms that may be important in relation to pancreatic disorders are pruritus, abdominal pain, dyspnea, nausea, and vomiting. The functional assessment includes data about the patient’s dietary habits and use of alcohol.

Note any restlessness, flushing, or diaphoresis during the examination. Vital signs may disclose low-grade fever, tachypnea, tachycardia, and hypotension. Inspect the skin for jaundice. Assess the abdomen for distention, tenderness, discoloration, and diminished bowel sounds.

Tests and procedures used to diagnose pancreatic disorders include laboratory analyses of blood, urine, stool, and pancreatic fluid, and imaging studies. Specific blood studies used to assess pancreatic function include measurements of serum amylase, lipase, glucose, calcium, and triglyceride levels. Urine amylase and renal amylase clearance tests may also be ordered. Stool specimens may be analyzed for fat content. The secretin stimulation test measures the bicarbonate concentration of pancreatic fluid after secretin is given intravenously to stimulate the production of pancreatic fluid.

"'Conjoined twins" are identical twins joined in utero. An extremely rare phenomenon, the occurrence is estimated to range from 1 in 49,000 births to 1 in 189,000 births, with a somewhat higher incidence in Southeast Asia and Africa. Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1.

Two contradicting theories exist to explain the origins of conjoined twins. The more generally accepted theory is "fission", in which the fertilized egg splits partially. The other theory, no longer believed to be the basis of conjoined twinning, is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find like-stem cells on the other twin and fuse the twins together. Conjoined twins share a single common chorion, placenta, and amniotic sac, although these characteristics are not exclusive to conjoined twins as there are some monozygotic but non-conjoined twins who also share these structures in utero.

The most famous pair of conjoined twins was Chang and Eng Bunker (Thai: อิน-จัน, In-Chan) (1811–1874), Thai brothers born in Siam, now Thailand. They traveled with P.T. Barnum's circus for many years and were labeled as the Siamese twins. Chang and Eng were joined at the torso by a band of flesh, cartilage, and their fused livers. In modern times, they could have been easily separated. Due to the brothers' fame and the rarity of the condition, the term "Siamese twins" came to be used as a synonym for conjoined twins.

Treatment of accessory pancreas depends on the location and extent of the injured tissue. Surgery may be an option, or some physicians order prophylactic antibiotics.

Three main points in diagnosing thumb hypoplasia are: width of the first web space, instability of the involved joints and function of the thumb. Thorough physical examination together with anatomic verification at operation reveals all the anomalies. An X-ray of the hand and thumb in two directions is always mandatory. When the pediatrician thinks the condition is associated with some kind of syndrome other tests will be done. More subtle manifestations of types I and II may not be recognized, especially when more obvious manifestations of longitudinal radial deficiency in the opposite extremity are present. Therefore, a careful examination of both hands is important.

Multiview videofluoroscopy is a radiographic technique, mostly to demonstrate the lateral and posterior wall of the pharynx. This is a questionable technique considering these children undergo radiographic examinations frequently. Also known is that children are more sensitive to radiographic examinations than adults. Most of the time barium is used in multiview videofluoroscopy. Besides the fact that videofluoroscopy provides an overview of the lateral and posterior walls of the pharynx, this technique also provides information about the length and movement of the soft palate, the posterior and the lateral walls.

A limitation of multiview videofluoroscopy is the possibility of misinterpreting certain shapes of gaps and anatomic structures.

The most frequently used diagnostic tools are videofluoroscopy and nasoendoscopy. Some studies conclude that the first step in the process of diagnosis is videofluoroscopy in combination with nasometry. Other studies show a favour for nasoendoscopy. But in general there is no preference for which tool should be used as a standard. Most studies conclude that it is necessary to make an individual decision on which diagnostic tool should be used.

A relatively new approach in the diagnosis is magnetic resonance imaging (MRI), which is noninvasive. MRI uses the property of nuclear magnetic resonance to image nuclei of atoms inside the body. MRI is non-radiographic and therefore can be repeated more often in short periods of time. In addition, different studies show that the MRI is better as a diagnostic tool than videofluoroscopy for visualizing the anatomy of the velopharynx.

On the contrary there are still a few limitations of the MRI. Firstly, artifacts can be shown on the images when the patient moves while imaging. Also artifacts will also be shown if the patient has orthodontic appliances. Secondly, the MRI is limited in children who are claustrophobic.

Furthermore, in the MRI scanner movement of the sphincter leads to artifacts on the images. Therefore, nasoendoscopy is still needed for information about the sphincter’s movement. Finally, the MRI is a more expensive diagnostic tool than the combination of nasoendoscopy and videofluoroscopy.

Because of these limits, MRI is currently not widely used. Overall, MRI is used for a “bird's eye view” of the child in the planning of the operation, but not in the progress of diagnosis.

The differential diagnoses are extensive and include: Alagille syndrome, alpha-1-antitrypsin deficiency, Byler disease (progressive familial intrahepatic cholestasis), Caroli disease, choledochal cyst, cholestasis, congenital cytomegalovirus disease, congenital herpes simplex virus infection, congenital rubella, congenital syphilis, congenital toxoplasmosis, cystic fibrosis, galactosemia, idiopathic neonatal hepatitis, lipid storage disorders, neonatal hemochromatosis, and total parenteral nutrition-associated cholestasis.

When it comes to treatment it is important to differentiate a thumb that needs stability, more web width and function, or a thumb that needs to be replaced by the index finger. Severe thumb hypoplasia is best treated by pollicization of the index finger. Less severe thumb hypoplasia can be reconstructed by first web space release, ligament reconstruction and muscle or tendon transfer.

It has been recommended that pollicization is performed before 12 months, but a long-term study of pollicizations performed between the age of 9 months and 16 years showed no differences in function related to age at operation.

It is important to know that every reconstruction of the thumb never gives a normal thumb, because there is always a decline of function. When a child has a good index finger, wrist and fore-arm the maximum strength of the thumb will be 50% after surgery in comparison with a normal thumb. The less developed the index finger, wrist and fore-arm is, the less strength the reconstructed thumb will have after surgery.

There are multiple classifications for the triphalangeal thumb. The reason for these different classifications is the heterogeneity in appearance of the TPT.

The classification according to Wood describes the shape of the extra phalanx: delta (Fig. 4), rectangular or full phalanx (Table 1). With the classification made by Buck-Gramcko a surgical treatment can be chosen (Table 1). Buck-Gramcko differentiates between six different shapes of the extra phalanx and associated malformations.

Table 1: Classifications of Wood and Buck-Gramcko

With so few individuals actually surviving until birth, the only treatment option is surgery to try to remove the parasitic twin. Surgery, however, is very dangerous and has been successful only once. The problem with surgical intervention is that the arterial supplies of the head are so intertwined that it is very hard to control the bleeding, and it has been suggested that cutting off the parasitic twin's arterial supply might improve the odds of the developed twin's survival.

In 1996, they traveled to Germany, trying to convince doctors there to separate them; the German doctors however declined to operate, saying that the risk of separation surgery would be too high for both of them.

In November 2002, after meeting Dr. Keith Goh, the Bijani sisters travelled to Singapore to undergo the controversial operation. Even though they were warned by the doctors that the surgery to separate them would still be very risky, the sisters were very determined. Their decision to go ahead with the operation caused an international media blitz.

After eight months in Singapore, doing extensive psychiatric and legal evaluations, they underwent surgery on July 6, 2003, under the care of a large team of international specialists at Raffles Hospital, composed of 28 surgeons (including neurosurgeon Ben Carson) and more than 100 support staff working in shifts. A specially-designed chair was required that allowed the operation to be performed with both sisters in a sitting position.

The attempt to separate the twins turned out to be very difficult, because their brains not only shared a major vein (the superior sagittal sinus), but had fused together. The separation was achieved on July 8, 2003, but it was announced then that the twins were in critical condition, both having lost a large volume of blood due to complications of the operation.

The separation stage of the surgery completed at 13:30 (Singapore time, UTC +8), but there was significant blood loss during the blood vessel repairing process, and Ladan died at around 14:30 on the operating table; her sister Laleh died about 90 minutes later. Their deaths were announced by the chairman of Raffles Hospital, Dr. Loo Choon Yong.

The usual treatment is splenopexy, fixation of the spleen, but if there is no blood flow after unwinding the spleen through detorsion then splenectomy must be performed. Although there have been few reported cases of treatment through laparoscopic surgery due to the rarity of the disease, it has been proven to be an effective surgical technique.