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The “Allis” test for easy cesarean delivery
The "Allis" test for easy cesarean delivery Michael A. Finan, MD, Dimitrios S. Mastrogiannis, MD, PhD, and William N. Spellacy, MD Tampa, Florida Cesarean delivery may be complicated by dystocia if the incision size is inadequate. A test is described that may be easily applied at cesarean section, creating greater objectivity in the determination of surgical incision size. One hundred patients were studied prospectively. Patients with incisions that passed the test had a shorter mean time of delivery and less difficult deliveries than those of patients with incisions that failed the test. We conclude that the "Allis" test is a simple way to reduce the incidence of dystocia at cesarean delivery. (AM J OaSTET GVNECOL 1991 ;164:772-5.)
Key words: Test, cesarean section, dystocia Cesarean section is the most common major surgical procedure in the field of obstetrics and gynecology.' Cosmetic considerations may exert pressure on the surgeon to produce incisions that are small, and thus less disfiguring. However, smaller incisions often restrict exposure of the operative field and may increase the difficulty of delivery. In 1987 Ayers and Morley" determined that an abdominal incision size ~ 15 cm is associated with significantly less difficulty in cesarean delivery. Their efforts stimulated interest in the development of an efficient and simple way to test the wound size and thus reduce the incidence of difficulty at cesarean delivery. The purpose of this study was to develop a test that would predict easy cesarean delivery and thus reduce dystocia and speed delivery at cesarean section. The test proposed is to use a common instrument, the Allis forceps, as a wound size gauge. This forcep measures approximately 15 cm in length and is readily available.
Material and methods Between Jan. 1 and April 30, 1990, 100 patients undergoing cesarean section at Tampa General Hospital were prospectively entered in the study. The surgery was performed by the resident staff and the attending physicians. A vertical or Pfannenstiel skin incision was performed. After entering the peritoneal cavity, two Richardson retractors were used to retract
From the Department of Obstetrics and Gynecology, University of South Florida College of Medicine. Received for publication June 22, 1990.. revised October 22, 1990; accepted November 6, 1990. Reprint requests: Michael A. Finan, MD, Department of Obstetrics and Gynecology, Suite 529, Harbour-Side Medical Tower, 4 Columbia Dr., Davis Islands, Tampa, FL 33606.
6/1/26585
772
Table I. Operative and delivery data Passed group
I
%
P Value
54 7
88 12
NS NS
56 26 18
49 5 7
80 8 12
NS NS NS
24 15
61 39
44 17
72 28
NS NS
22 17
56 44
36 25
59 41
NS NS
28
72
48 13
79 21
NS NS
%
No.
31 8
79 21
22 10 7
No.
Skin incision Pfannenstiel Vertical Anesthesia Epidural General Spinal Presentation Vertex Breech Sex Male Female Cesarean section Primary Repeat
I
Failed group
II
28
the abdominal walls laterally. An Allis clamp was then held between the retractors. The test was described as "passed" if the clamp easily fit between the retractors and "failed" if the clamp was longer than the distance between the retractors, as in Fig. 1. The cesarean delivery was undertaken in the usual fashion,'" regardless of the outcome of the test. All the uterine incisions were of the low-transverse type. To objectively assess difficulty of delivery a circulating nurse recorded the length of time in seconds between the start of the uterine incision, after the bladder was removed from the lower segment, and delivery of the fetus. The operators subjectively graded the difficulty of delivery with a scale of I to IV as follows: I = no dystocia, very easy delivery; II = moderate effort required to effect delivery; III = forceful abdominal pressure required for delivery; IV = extension of the incision or muscle splitting was required for delivery.
"Allis" precesarean test
Volume 164 Number 3
773
Table II. Demographic and delivery data Passed group Mean
Age (yr) Parity Gestational age (wk) Birth weight (gm) Cord pH Time from incision to delivery (seconds)
25.3 1.2 38.8 3505 7.26 58.4
I
Failed group Range
Mean
16-35 0-5 28-42 1100-5585 7.07-7.36 15-190
Obstetric and epidemiologic data were obtained from the medical records of these patients. The results were analyzed statistically with the Student's t test and X2 test where appropriate. The analysis was performed with the assistance of the SPSS statistical computer package. A p value of <0.05 was considered significant.
22.7 0.7 39.1 3305 7.26 95.7
Range
p Value
16-35 0-6 34-43 1950-4850 7.15-7.34 30-270
0.02 0.03 NS NS NS 0.002
Table III. Relationship of grade of dystocia to I-minute Apgar scores Passed group Grade of dystocia
Results
Of the 100 patients entered in the study, 39 incisions passed the "Allis" test and 61 incisions failed the test. The patients were similar with regard to type of skin incision, type of anesthesia, presentation, and sex of the fetus, as shown in Table I. Sixty-eight (68%) of the patients had a fetus in the vertex presentation and 32 (32%) were breech. In the group with incisions that passed the test, 24 (61 %) were vertex and 15 (39%) were breech. In the group with incisions that failed the test, 44 (72%) were vertex and 17 (28%) were breech. These differences were not statistically significant. A total of 85% of the skin incisions were Pfannenstiel and 15% were vertical. The majority of cesarean sections were primary (76%) with 24% being repeat cesarean sections. Of the group with incisions that passed the test, 28 (72%) underwent primary and 11 (28%) underwent repeat cesarean sections. Of the group with incisions that failed the test, 48 (79%) were primary and 13 (21 %) were repeat cesarean sections. These differences were not statistically significant. The group with incisions that passed the "Allis" test had a higher mean age and parity than those of the group with incisions that failed the test. The groups were similar with regard to gestational age, birth weight, and cord pH as shown in Table II. The patients with incisions that passed the test had a shorter length of time from uterine incision to delivery than that of those with incisions that failed the test. The mean time of delivery was 58.4 seconds (range, 15 to 190) for those with incisions that passed the test and 95.7 seconds (range, 30 to 270) for those with incisions that failed the test (p < 0.005). The group with incisions that passed the test had a
_1-
II
III
IV
1 min Apgar score
Failed group
No·1
%*
No.1
%t
p Value
9 8 7 6 5 4 3
19 4
48.7 10.2
13 3
4
10.2 2.6
21.4 4.9 1.6 1.6 3.3 1.6
NS NS NS NS NS NS
9 8 7 6 5
4
22.9 9.9 3.3 1.6 3.3
NS NS NS NS NS
I I
11.6 3.3 1.6 1.6
NS NS NS NS
3
4.9
NS
9 8 7 6 9 8 7 6 5 4 3
I
I I
2 I
I I
2
10.2 2.6 2.6 5.1
14 6 2
2.6
7 2
2.6
I
2
2.6
NS 1.6
NS
*P Value, 0.014. tp Value, NS. statistically significant difference (p < 0.05) between the I-minute Apgar scores for each grade of dystocia. In the group with incisions that failed the test, we found no difference between the I-minute Apgar scores and the four grades of dystocia (see Table III). Comparison of the Apgar scores for every grade of dystocia within each ofthe two groups (passed and failed) did not show a statistically significant difference. Fig. 2 shows the percentage of patients in each group (passed versus failed) with a particular grade of dystocia. A total of 26.3% of patients with incisions that failed the test had a grade III or IV delivery, whereas
774
Finan, Mastrogiannis, and Spellacy
March 1991 Am J Obstet Gynecol
Fig. 1. Use of Allis test quickl y shows that incision may be too small to allow easy delivery.
% OF PATIENTS IN EACH GROUP 80 ~------------------------------------------------~
71.8
60
40
20
o
II
III
IV
GRADE OF DYSTOCIA _
PASSED ALLIS TEST
~ FAILED ALLIS TEST
I
Fig. 2. Percentage of patients in each group for each given grade of dystocia.
only 7.7 % of those with incisions that passed the test had a delivery of this difficulty (p < 0.05). Comment
The tendency of surgeons to create smaller incisions for cosmetic reasons is understandable . Williams' Obstetrics" states that the cesarean section incision should be of sufficient length to permit delivery of the infant without difficulty. Ayers and Morley 2 determined that difficult deliveries, in which forceful pressure on the maternal abdomen was required to effect delivery or
in which enlargement of the incision was required for delivery of the infant, were related to an incision size < 15 cm. The same study suggested that the degree of difficulty during delivery of the fetus correlates inversely with incision size. The present study evaluated prospectively a test that would predict easier, more rapid delivery at cesarean section. The groups were similar with regard to birth weight, gestational age, and cord pH. The fact that the group with incisions that passed the "Allis" test had a higher mean age and parity than those of the grou p
"Allis" precesarean test
Volume 164 Number 3
with incisions that failed the test could be explained because of more relaxed abdominal walls in this group.5 The group with incisions that passed the "Allis" test who were delivered of infants with grades I and II dystocia had significantly higher I-minute Apgar scores than those with grades III and IV dystocia (p < 0.05). This difference was not found for the group with incisions that failed the test. Comparison of I-minute Apgar scores of the two groups (passed versus failed) shows there was no statistically significant difference. There was also no difference within each group or between the groups in the 5-minute Apgar scores. These differences may be elicited with larger numbers in each group. The failed "Allis" test was associated with a longer delivery time and a significantly more difficult delivery than was the passed "Allis" test. Factors that affect difficulty of cesarean delivery are varied. They include parity, abdominal wall relaxation, station, position of the presenting part, and size of sur-
775
gical incision. One of the factors that we can control to reduce the incidence of dystocia at cesarean delivery is the size of the surgical incision. We conclude that application of the "Allis" test is an objective way to control the size of surgical incision at cesarean delivery. The Allis clamp measures approximately 15 cm and is readily available. If the instrument fits between two retractors that distend the abdominal incision laterally, the delivery can be carried out easily. REFERENCES 1. Bottoms SF, Rosen MG, Sokol RJ. The increase in cesarean birth rate. N Engl J Med 1980;302:559. 2. Ayers JWT, Morley GW. Surgical incision for cesarean section. Obstet Gynecol 1987;70:706. 3. Mattingly RF, Thompson JD. TeLinde's gynecology. 6th ed. Philadelphia: JB Lippincott Co, 1985: 157-64. 4. Cunningham FG, MacDonald PC, Gant NF. Williams' obstetrics. 18th ed. Norwalk, Connecticut: Appleton and Lange, 1989:447-53. 5. Vorherr H. Gynecology and obstetrics. vol 2. Philadelphia: JB Lippincott, 1989: 10.
Bound volumes available to subscribers Bound volumes of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY are available to subscribers (only) for the 1991 issues from the Publisher, at a cost of $61.00 ($84.00 international) for Vol. 164 (January-June) and Vol. 165 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the JOURNAL name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby- Year Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 631463318, USA; phone (800) 325-4177, ext. 4351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.
Key words: Test, cesarean section, dystocia Cesarean section is the most common major surgical procedure in the field of obstetrics and gynecology.' Cosmetic considerations may exert pressure on the surgeon to produce incisions that are small, and thus less disfiguring. However, smaller incisions often restrict exposure of the operative field and may increase the difficulty of delivery. In 1987 Ayers and Morley" determined that an abdominal incision size ~ 15 cm is associated with significantly less difficulty in cesarean delivery. Their efforts stimulated interest in the development of an efficient and simple way to test the wound size and thus reduce the incidence of difficulty at cesarean delivery. The purpose of this study was to develop a test that would predict easy cesarean delivery and thus reduce dystocia and speed delivery at cesarean section. The test proposed is to use a common instrument, the Allis forceps, as a wound size gauge. This forcep measures approximately 15 cm in length and is readily available.
Material and methods Between Jan. 1 and April 30, 1990, 100 patients undergoing cesarean section at Tampa General Hospital were prospectively entered in the study. The surgery was performed by the resident staff and the attending physicians. A vertical or Pfannenstiel skin incision was performed. After entering the peritoneal cavity, two Richardson retractors were used to retract
From the Department of Obstetrics and Gynecology, University of South Florida College of Medicine. Received for publication June 22, 1990.. revised October 22, 1990; accepted November 6, 1990. Reprint requests: Michael A. Finan, MD, Department of Obstetrics and Gynecology, Suite 529, Harbour-Side Medical Tower, 4 Columbia Dr., Davis Islands, Tampa, FL 33606.
6/1/26585
772
Table I. Operative and delivery data Passed group
I
%
P Value
54 7
88 12
NS NS
56 26 18
49 5 7
80 8 12
NS NS NS
24 15
61 39
44 17
72 28
NS NS
22 17
56 44
36 25
59 41
NS NS
28
72
48 13
79 21
NS NS
%
No.
31 8
79 21
22 10 7
No.
Skin incision Pfannenstiel Vertical Anesthesia Epidural General Spinal Presentation Vertex Breech Sex Male Female Cesarean section Primary Repeat
I
Failed group
II
28
the abdominal walls laterally. An Allis clamp was then held between the retractors. The test was described as "passed" if the clamp easily fit between the retractors and "failed" if the clamp was longer than the distance between the retractors, as in Fig. 1. The cesarean delivery was undertaken in the usual fashion,'" regardless of the outcome of the test. All the uterine incisions were of the low-transverse type. To objectively assess difficulty of delivery a circulating nurse recorded the length of time in seconds between the start of the uterine incision, after the bladder was removed from the lower segment, and delivery of the fetus. The operators subjectively graded the difficulty of delivery with a scale of I to IV as follows: I = no dystocia, very easy delivery; II = moderate effort required to effect delivery; III = forceful abdominal pressure required for delivery; IV = extension of the incision or muscle splitting was required for delivery.
"Allis" precesarean test
Volume 164 Number 3
773
Table II. Demographic and delivery data Passed group Mean
Age (yr) Parity Gestational age (wk) Birth weight (gm) Cord pH Time from incision to delivery (seconds)
25.3 1.2 38.8 3505 7.26 58.4
I
Failed group Range
Mean
16-35 0-5 28-42 1100-5585 7.07-7.36 15-190
Obstetric and epidemiologic data were obtained from the medical records of these patients. The results were analyzed statistically with the Student's t test and X2 test where appropriate. The analysis was performed with the assistance of the SPSS statistical computer package. A p value of <0.05 was considered significant.
22.7 0.7 39.1 3305 7.26 95.7
Range
p Value
16-35 0-6 34-43 1950-4850 7.15-7.34 30-270
0.02 0.03 NS NS NS 0.002
Table III. Relationship of grade of dystocia to I-minute Apgar scores Passed group Grade of dystocia
Results
Of the 100 patients entered in the study, 39 incisions passed the "Allis" test and 61 incisions failed the test. The patients were similar with regard to type of skin incision, type of anesthesia, presentation, and sex of the fetus, as shown in Table I. Sixty-eight (68%) of the patients had a fetus in the vertex presentation and 32 (32%) were breech. In the group with incisions that passed the test, 24 (61 %) were vertex and 15 (39%) were breech. In the group with incisions that failed the test, 44 (72%) were vertex and 17 (28%) were breech. These differences were not statistically significant. A total of 85% of the skin incisions were Pfannenstiel and 15% were vertical. The majority of cesarean sections were primary (76%) with 24% being repeat cesarean sections. Of the group with incisions that passed the test, 28 (72%) underwent primary and 11 (28%) underwent repeat cesarean sections. Of the group with incisions that failed the test, 48 (79%) were primary and 13 (21 %) were repeat cesarean sections. These differences were not statistically significant. The group with incisions that passed the "Allis" test had a higher mean age and parity than those of the group with incisions that failed the test. The groups were similar with regard to gestational age, birth weight, and cord pH as shown in Table II. The patients with incisions that passed the test had a shorter length of time from uterine incision to delivery than that of those with incisions that failed the test. The mean time of delivery was 58.4 seconds (range, 15 to 190) for those with incisions that passed the test and 95.7 seconds (range, 30 to 270) for those with incisions that failed the test (p < 0.005). The group with incisions that passed the test had a
_1-
II
III
IV
1 min Apgar score
Failed group
No·1
%*
No.1
%t
p Value
9 8 7 6 5 4 3
19 4
48.7 10.2
13 3
4
10.2 2.6
21.4 4.9 1.6 1.6 3.3 1.6
NS NS NS NS NS NS
9 8 7 6 5
4
22.9 9.9 3.3 1.6 3.3
NS NS NS NS NS
I I
11.6 3.3 1.6 1.6
NS NS NS NS
3
4.9
NS
9 8 7 6 9 8 7 6 5 4 3
I
I I
2 I
I I
2
10.2 2.6 2.6 5.1
14 6 2
2.6
7 2
2.6
I
2
2.6
NS 1.6
NS
*P Value, 0.014. tp Value, NS. statistically significant difference (p < 0.05) between the I-minute Apgar scores for each grade of dystocia. In the group with incisions that failed the test, we found no difference between the I-minute Apgar scores and the four grades of dystocia (see Table III). Comparison of the Apgar scores for every grade of dystocia within each ofthe two groups (passed and failed) did not show a statistically significant difference. Fig. 2 shows the percentage of patients in each group (passed versus failed) with a particular grade of dystocia. A total of 26.3% of patients with incisions that failed the test had a grade III or IV delivery, whereas
774
Finan, Mastrogiannis, and Spellacy
March 1991 Am J Obstet Gynecol
Fig. 1. Use of Allis test quickl y shows that incision may be too small to allow easy delivery.
% OF PATIENTS IN EACH GROUP 80 ~------------------------------------------------~
71.8
60
40
20
o
II
III
IV
GRADE OF DYSTOCIA _
PASSED ALLIS TEST
~ FAILED ALLIS TEST
I
Fig. 2. Percentage of patients in each group for each given grade of dystocia.
only 7.7 % of those with incisions that passed the test had a delivery of this difficulty (p < 0.05). Comment
The tendency of surgeons to create smaller incisions for cosmetic reasons is understandable . Williams' Obstetrics" states that the cesarean section incision should be of sufficient length to permit delivery of the infant without difficulty. Ayers and Morley 2 determined that difficult deliveries, in which forceful pressure on the maternal abdomen was required to effect delivery or
in which enlargement of the incision was required for delivery of the infant, were related to an incision size < 15 cm. The same study suggested that the degree of difficulty during delivery of the fetus correlates inversely with incision size. The present study evaluated prospectively a test that would predict easier, more rapid delivery at cesarean section. The groups were similar with regard to birth weight, gestational age, and cord pH. The fact that the group with incisions that passed the "Allis" test had a higher mean age and parity than those of the grou p
"Allis" precesarean test
Volume 164 Number 3
with incisions that failed the test could be explained because of more relaxed abdominal walls in this group.5 The group with incisions that passed the "Allis" test who were delivered of infants with grades I and II dystocia had significantly higher I-minute Apgar scores than those with grades III and IV dystocia (p < 0.05). This difference was not found for the group with incisions that failed the test. Comparison of I-minute Apgar scores of the two groups (passed versus failed) shows there was no statistically significant difference. There was also no difference within each group or between the groups in the 5-minute Apgar scores. These differences may be elicited with larger numbers in each group. The failed "Allis" test was associated with a longer delivery time and a significantly more difficult delivery than was the passed "Allis" test. Factors that affect difficulty of cesarean delivery are varied. They include parity, abdominal wall relaxation, station, position of the presenting part, and size of sur-
775
gical incision. One of the factors that we can control to reduce the incidence of dystocia at cesarean delivery is the size of the surgical incision. We conclude that application of the "Allis" test is an objective way to control the size of surgical incision at cesarean delivery. The Allis clamp measures approximately 15 cm and is readily available. If the instrument fits between two retractors that distend the abdominal incision laterally, the delivery can be carried out easily. REFERENCES 1. Bottoms SF, Rosen MG, Sokol RJ. The increase in cesarean birth rate. N Engl J Med 1980;302:559. 2. Ayers JWT, Morley GW. Surgical incision for cesarean section. Obstet Gynecol 1987;70:706. 3. Mattingly RF, Thompson JD. TeLinde's gynecology. 6th ed. Philadelphia: JB Lippincott Co, 1985: 157-64. 4. Cunningham FG, MacDonald PC, Gant NF. Williams' obstetrics. 18th ed. Norwalk, Connecticut: Appleton and Lange, 1989:447-53. 5. Vorherr H. Gynecology and obstetrics. vol 2. Philadelphia: JB Lippincott, 1989: 10.
Bound volumes available to subscribers Bound volumes of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY are available to subscribers (only) for the 1991 issues from the Publisher, at a cost of $61.00 ($84.00 international) for Vol. 164 (January-June) and Vol. 165 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the JOURNAL name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby- Year Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 631463318, USA; phone (800) 325-4177, ext. 4351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.