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Separation of omphalopagus twins
Separation of Omphalopagus Twins By Kenneth Kenigsberg and Rita G. Harper N e w York, N e w York 9 The study and successful separation of a pair of omphalopagus twins weighing 1690 g at birth is presented. The test of greatest usefulness was an oral glucose tolerance test that demonstrated an absence of parasitism. Subsequently, it was found that the twins had a joined liver but separate GI and GU tracts. The time for separation was determined by observing the twins" toleration of compression of the bridge. Initially, obliteration of the tunnel-like connection would cause considerable respiratory distress. H o w e v e r , in the month before surgery, the tunnel could be compressed to the point of obliteration without causing tachypnea or other signs of respiratory distress. The change in toleration of compression was related to unequal g r o w t h of the twins and their connecting bridge. Though the weight of the twins q u i n t u p l e d in their first 6 mo, the circumference of the bridge remained the same. The surgery was carried o u t on a single table w i t h o u t frames. The twins w e r e draped using self-adhering plastic. Intravenous fluoroscein was used t o demarcate the large liver juncture, thus expediting the separation. INDEX WORDS: Omphalopagus twins.
I A M E S E T W I N S may be joined anywhere from the head to the leg. The most common site of union is the upper abdomen and lower chest. If the joined area includes both thoracic and abdominal viscera, the condition is referred to as thoracopagus and if the juncture is confined to the upper abdomen, it is referred to as omphalopagus. It is the latter type with which this paper is concerned. Omphalopagus joining, sometimes referred to as xiphopagus, is the type most amenable to total successful correction. Nevertheless, separation is successful in only 50% of the reported cases. ~The mortality of attempted separation of omphalopagus twins is related to problems of evaluation, timing, and closure. We found in concluding a successful separation that there were a number of points in each of these areas which were of help.
S
EVALUATION
B. and L. were in excellent condition after their emergency cesarean delivery. However, they weighed only 1690 g (Fig. 1). It was considered essential that they be nourished adequately
Journal of Pediatric Surgery, Vol. 17, No. 3 (June), 1982
as soon as possible. Obviously, the best way of carrying this out would be by oral feeding. However, we were concerned that there might be some degree of parasitism and that food administered to one twin might find its way into the body of the other, either because there was intestinal or circulatory crossover. An oral glucose tolerance test as described by Spencer 2 was carried out on each twin. This produced a normal rise in the blood glucose only in the twin to whom the glucose had been administered (Fig. 2). This gave us the confidence to give first tube feeding and then nipple feedings until an adequate weight gain was accomplished. TIMING
If the omphalocele accompanying conjoined twins is ruptured or if the clinical condition of the twins deteriorates, immediate surgical correction is indicated. 3 If the children are doing well, however, it is generally considered wiser to wait before carrying out the separation. But what is the proper time; what can be used as an indicator to determine time of operation? It seemed to us upon reviewing previous cases, that the critical consideration in dividing omphalopagus twins was respiratory. If the separation caused a large defect, the tension of closure would interfere with respiration. To avoid this problem, preoperative stretching by pneumo peritoneum 4 or patching the defect with prosthetic material 5 has been recommended. Both carry a risk of infection, however. We thought that the solution to the difficulty might arise from growth disproportion between the connecting bridge and the abdominal cavities of the twins. Starting at about the sixth week of life, the bridge was manually compressed. It was From the Departments o f Surgery and Pediatrics and Obstetrics and Gynecology, North Shore University Hospital, Manhasset, N.Y., and the Departments o f Surgery and Pediatrics and Obstetrics and Gynecology, Cornell University Medical College, New York, N.Y. Address reprint requests to Kenneth Kenigsberg, M.D., 520 Franklin Ave., Garden City, N.Y. 11530. 9 1982 by Grune & Stratton, Inc. 0022-3468/82/1703~9007501.00/0
255
256
KENIGSBERG A N D HARPER
Twins, age 2 hr.
Fig. 1.
ORAL GLUCOSE TOLERANCE TESTS TWIN "~' GIVENONE GRAM C4-~ BY N-G TL~s
!25f BLOOD GLUCOSE Mg/lOC~:c
D-"
',
10C>[ 75
," O
"'
0 x
X~...
TWIN ' ~ " 0 - - - - 0 TWIN "B" x - - •
~-~•
5O 25 0
30
60
90
TIME IN MINUTES TWIN ''B" GIVENONE GR,NM CNJ.JCOC:~BY N--G ~JEE 125 BLOOD GLUCOSE ivlg/lOOcc
100
TWIN '~" o-- o TWIN"B" x - - x
75 50 ...... o . . . . O--L--L _o
25
0
30
60
90
TIME IN MINUTES Fig. 2.
N-G t u b e ) .
quite easy to palpate the bony bridge above, the solid mass of liver below the bony union and the large open area inferior to the liver. On G | series, it had been found that the open area inferior to the liver contained a shared peritoneal cavity through which the separate intestinal tract of each twin freely herniated. Initially, compressing this defect constricted the abdominal wall and caused respiratory distress. If the compression were carried out when the twins were asleep, they would quickly become dyspneic and awaken. Over the ensuing 4 mo, it was noted that compression even to the point of obliteration of the cavity caused less and less respiratory distress. By 6 mo of age, the open area of the bridge would be completely closed by digital pressure while the children were asleep without awakening the children or causing an increase in their respiratory rate. It was also noted that the circumference of the bridge, 22 cm, remained unchanged, in spite of a five-fold increase in their combined weight. Thus, it appeared that the twins were better able to tolerate closure of the abdominal defect as they got older because the ratio of" the abdominal cavity size to bridge size increased. Indeed, at the time of surgery, the closure of the abdominal wall defect was carried out easily and appeared to involve an amount of tension approximately equal to that necessary to obliterate the cavity before the operation.
Oral glucose tolerance test (1 g glucose given by
CLOSURE
We had originally planned to use an R frame for each child and a separate table as recommended by Kiesewetter. ~ However, as we went through the rehearsals and manipulations before the operation, it seemed unnecessary to us to use either the frame or two separate tables. The final positioning and draping was relatively simple. The patients were placed on a table lying on their sides. A separate anesthesiologist put each twin to sleep using halothane administered by mask. Intubation was carried out smoothly with each twin's head turned to the side. The radial arteries and the saphenous veins were cannulated (Fig. 3). After attachment of the sensing wires, the twins were held in mid-air and the table was moved out from beneath them. Their torsos were washed on both sides with an iodophor solution. The torsos were dried with sterile towels and
SEPARATION OF OMPHALOPAGUS TWINS
Fig. 3.
257
After endotracheal intubation.
self-adhering drapes were applied across the lateral aspects of both twins' torsos. Above and below the bridge of connecting tissue, the selfadhering tapes were stuck to each other, thus enclosing the chest and abdomen of each child as well as the connecting bridge in a cocoon of plastic. The twins were then replaced on the table that had been covered with a sterile sheet. At the conclusion of the separation, each twin was rolled onto her back, away from the other twin as described by Kling et al. 6 The closure was completed quite easily by two separate teams working on each side of the table. At the time of the operation, we were concerned about the proper area of demarcation. There was no clearly defined area of separation of the skin nor was there any line on the liver as reported by de Vries. 5 Since we knew from radioisotope studies, that there was little vascular crossover, we assumed that we could delineate the twins by some type of vascular marker. As described by Venes 7 for meningocele closure, 1 cc of Fluorescein was injected intravenously into twin B and the area of the bridge was inspected with an ultraviolet light. The skin of the twin to whom the Fluorescein had been administered glowed brilliantly and there was a sharp area of demarcation where the skin bridge joined the other twin. After the abdominal wall had been opened, and the liver inspected, it was noted that there was a similar demarcation on the liver. This permitted rapid, relatively bloodless separation of the liver with simple mattress closure of the cut ends. An unexpected bonus of the maneuver was that the blood from the injected twin fluoresced whereas the blood from the noninjected twin did not. Thus, it was easy to determine from which twin the bleeding arose.
Fig. 4.
Age 2 yr.
Twin B had an episode of intestinal obstruction secondary to volvulus t wk postoperatively, which required operative correction. Otherwise, the twins have had an uneventful recovery from their separation (Fig. 4). CONCLUSIONS
( l ) Oral glucose tolerance tests help define vascular and intestional connection thereby permitting oral nutrition. (2) The bridge connecting omphalopagus twins does not appear to grow in diameter whereas the abdominal cavities do. Therefore, closure of the abdominal wall defect after separation becomes easier as the twins become larger. (3) The relative difficulty of closing the abdominal wall defect can be estimated by compressing the bridge while the twins are relaxed, as in deep sleep. (4) Intravenous Fluorescein administered to one of the twins is a useful aid in demarcating one child's organs from the other. (5) Spearation of twins on one table without a frame is simple and feasible.
258
KENIGSBERG AND HARPER
REFERENCES 1. Kiesewetter WB: Surgery on conjoined (Siamese) twins. Surgery 59:86ff-871, 1966 2. Spencer R: Surgical separation of Siamese twins: Case report. Surgery 39:827-833, 1956 3. Gans SL, Morgenstern L, Gettelman E, et al: Separation of conjoined twins in the neonatal period. J Pediatr Surg 3:565 574, 1968 4. Mestal AL, Golinko R J, Wax SH, et al: lschipagus tripus conjoined twins: Case report. Surgery 69:75-83, 1971
5. de Vries PA: Separation of the San Francisco twins. The National Foundation--March of Dimes; Birth Defects Original Article Series 111:75 79, 1967 6. Kling S, Johnston R J, Michalyshyn B, et al: Successful separation of xiphopagus-conjoined twins. J Pediatr Surg 10:267-271, 1975 7. Venes JL: The use of intravenous fluorescein in the repair of large myelomenigoceles. J Neurosurg 47:126 127, 1977
I A M E S E T W I N S may be joined anywhere from the head to the leg. The most common site of union is the upper abdomen and lower chest. If the joined area includes both thoracic and abdominal viscera, the condition is referred to as thoracopagus and if the juncture is confined to the upper abdomen, it is referred to as omphalopagus. It is the latter type with which this paper is concerned. Omphalopagus joining, sometimes referred to as xiphopagus, is the type most amenable to total successful correction. Nevertheless, separation is successful in only 50% of the reported cases. ~The mortality of attempted separation of omphalopagus twins is related to problems of evaluation, timing, and closure. We found in concluding a successful separation that there were a number of points in each of these areas which were of help.
S
EVALUATION
B. and L. were in excellent condition after their emergency cesarean delivery. However, they weighed only 1690 g (Fig. 1). It was considered essential that they be nourished adequately
Journal of Pediatric Surgery, Vol. 17, No. 3 (June), 1982
as soon as possible. Obviously, the best way of carrying this out would be by oral feeding. However, we were concerned that there might be some degree of parasitism and that food administered to one twin might find its way into the body of the other, either because there was intestinal or circulatory crossover. An oral glucose tolerance test as described by Spencer 2 was carried out on each twin. This produced a normal rise in the blood glucose only in the twin to whom the glucose had been administered (Fig. 2). This gave us the confidence to give first tube feeding and then nipple feedings until an adequate weight gain was accomplished. TIMING
If the omphalocele accompanying conjoined twins is ruptured or if the clinical condition of the twins deteriorates, immediate surgical correction is indicated. 3 If the children are doing well, however, it is generally considered wiser to wait before carrying out the separation. But what is the proper time; what can be used as an indicator to determine time of operation? It seemed to us upon reviewing previous cases, that the critical consideration in dividing omphalopagus twins was respiratory. If the separation caused a large defect, the tension of closure would interfere with respiration. To avoid this problem, preoperative stretching by pneumo peritoneum 4 or patching the defect with prosthetic material 5 has been recommended. Both carry a risk of infection, however. We thought that the solution to the difficulty might arise from growth disproportion between the connecting bridge and the abdominal cavities of the twins. Starting at about the sixth week of life, the bridge was manually compressed. It was From the Departments o f Surgery and Pediatrics and Obstetrics and Gynecology, North Shore University Hospital, Manhasset, N.Y., and the Departments o f Surgery and Pediatrics and Obstetrics and Gynecology, Cornell University Medical College, New York, N.Y. Address reprint requests to Kenneth Kenigsberg, M.D., 520 Franklin Ave., Garden City, N.Y. 11530. 9 1982 by Grune & Stratton, Inc. 0022-3468/82/1703~9007501.00/0
255
256
KENIGSBERG A N D HARPER
Twins, age 2 hr.
Fig. 1.
ORAL GLUCOSE TOLERANCE TESTS TWIN "~' GIVENONE GRAM C4-~ BY N-G TL~s
!25f BLOOD GLUCOSE Mg/lOC~:c
D-"
',
10C>[ 75
," O
"'
0 x
X~...
TWIN ' ~ " 0 - - - - 0 TWIN "B" x - - •
~-~•
5O 25 0
30
60
90
TIME IN MINUTES TWIN ''B" GIVENONE GR,NM CNJ.JCOC:~BY N--G ~JEE 125 BLOOD GLUCOSE ivlg/lOOcc
100
TWIN '~" o-- o TWIN"B" x - - x
75 50 ...... o . . . . O--L--L _o
25
0
30
60
90
TIME IN MINUTES Fig. 2.
N-G t u b e ) .
quite easy to palpate the bony bridge above, the solid mass of liver below the bony union and the large open area inferior to the liver. On G | series, it had been found that the open area inferior to the liver contained a shared peritoneal cavity through which the separate intestinal tract of each twin freely herniated. Initially, compressing this defect constricted the abdominal wall and caused respiratory distress. If the compression were carried out when the twins were asleep, they would quickly become dyspneic and awaken. Over the ensuing 4 mo, it was noted that compression even to the point of obliteration of the cavity caused less and less respiratory distress. By 6 mo of age, the open area of the bridge would be completely closed by digital pressure while the children were asleep without awakening the children or causing an increase in their respiratory rate. It was also noted that the circumference of the bridge, 22 cm, remained unchanged, in spite of a five-fold increase in their combined weight. Thus, it appeared that the twins were better able to tolerate closure of the abdominal defect as they got older because the ratio of" the abdominal cavity size to bridge size increased. Indeed, at the time of surgery, the closure of the abdominal wall defect was carried out easily and appeared to involve an amount of tension approximately equal to that necessary to obliterate the cavity before the operation.
Oral glucose tolerance test (1 g glucose given by
CLOSURE
We had originally planned to use an R frame for each child and a separate table as recommended by Kiesewetter. ~ However, as we went through the rehearsals and manipulations before the operation, it seemed unnecessary to us to use either the frame or two separate tables. The final positioning and draping was relatively simple. The patients were placed on a table lying on their sides. A separate anesthesiologist put each twin to sleep using halothane administered by mask. Intubation was carried out smoothly with each twin's head turned to the side. The radial arteries and the saphenous veins were cannulated (Fig. 3). After attachment of the sensing wires, the twins were held in mid-air and the table was moved out from beneath them. Their torsos were washed on both sides with an iodophor solution. The torsos were dried with sterile towels and
SEPARATION OF OMPHALOPAGUS TWINS
Fig. 3.
257
After endotracheal intubation.
self-adhering drapes were applied across the lateral aspects of both twins' torsos. Above and below the bridge of connecting tissue, the selfadhering tapes were stuck to each other, thus enclosing the chest and abdomen of each child as well as the connecting bridge in a cocoon of plastic. The twins were then replaced on the table that had been covered with a sterile sheet. At the conclusion of the separation, each twin was rolled onto her back, away from the other twin as described by Kling et al. 6 The closure was completed quite easily by two separate teams working on each side of the table. At the time of the operation, we were concerned about the proper area of demarcation. There was no clearly defined area of separation of the skin nor was there any line on the liver as reported by de Vries. 5 Since we knew from radioisotope studies, that there was little vascular crossover, we assumed that we could delineate the twins by some type of vascular marker. As described by Venes 7 for meningocele closure, 1 cc of Fluorescein was injected intravenously into twin B and the area of the bridge was inspected with an ultraviolet light. The skin of the twin to whom the Fluorescein had been administered glowed brilliantly and there was a sharp area of demarcation where the skin bridge joined the other twin. After the abdominal wall had been opened, and the liver inspected, it was noted that there was a similar demarcation on the liver. This permitted rapid, relatively bloodless separation of the liver with simple mattress closure of the cut ends. An unexpected bonus of the maneuver was that the blood from the injected twin fluoresced whereas the blood from the noninjected twin did not. Thus, it was easy to determine from which twin the bleeding arose.
Fig. 4.
Age 2 yr.
Twin B had an episode of intestinal obstruction secondary to volvulus t wk postoperatively, which required operative correction. Otherwise, the twins have had an uneventful recovery from their separation (Fig. 4). CONCLUSIONS
( l ) Oral glucose tolerance tests help define vascular and intestional connection thereby permitting oral nutrition. (2) The bridge connecting omphalopagus twins does not appear to grow in diameter whereas the abdominal cavities do. Therefore, closure of the abdominal wall defect after separation becomes easier as the twins become larger. (3) The relative difficulty of closing the abdominal wall defect can be estimated by compressing the bridge while the twins are relaxed, as in deep sleep. (4) Intravenous Fluorescein administered to one of the twins is a useful aid in demarcating one child's organs from the other. (5) Spearation of twins on one table without a frame is simple and feasible.
258
KENIGSBERG AND HARPER
REFERENCES 1. Kiesewetter WB: Surgery on conjoined (Siamese) twins. Surgery 59:86ff-871, 1966 2. Spencer R: Surgical separation of Siamese twins: Case report. Surgery 39:827-833, 1956 3. Gans SL, Morgenstern L, Gettelman E, et al: Separation of conjoined twins in the neonatal period. J Pediatr Surg 3:565 574, 1968 4. Mestal AL, Golinko R J, Wax SH, et al: lschipagus tripus conjoined twins: Case report. Surgery 69:75-83, 1971
5. de Vries PA: Separation of the San Francisco twins. The National Foundation--March of Dimes; Birth Defects Original Article Series 111:75 79, 1967 6. Kling S, Johnston R J, Michalyshyn B, et al: Successful separation of xiphopagus-conjoined twins. J Pediatr Surg 10:267-271, 1975 7. Venes JL: The use of intravenous fluorescein in the repair of large myelomenigoceles. J Neurosurg 47:126 127, 1977