- Email: [email protected]
Direct laparoscopic entry using a sharp and dull trocar technique
William H. James f
The Galton Laboratory University College London WolfsonHouse 4 Sfepkenson Way Londoz NW 1 2 HE England
Letters
References 1. Cooperstock
EXCESS MALES IN PRETERM
BIRTH: 2.
INTERACTIONS AGE,RACE,AND
WITH
GESTATIONAL
MULTIPLE
BIRTH
3. 4.
To tke Editor:
Cooperstock and Campbell1 note that the sex ratio (proportion male) of live births declines with duration of gestation (dated from reported last menstruation). They found that this associationis far more powerful in white than black births and, within white births, more powerful in those to married women, those to women aged more than 20 years, and those to women educated for 12 years or more. They write, “The excessof males [in preterm births] in selected groups suggests the existence of a mechanism of preterm birth influenced by fetal gender, “ and, “Preterm births in blacks and in twin gestations greater than 33 weeks may be more often due to alternative mechanismsthat are independent of fetal gender.” I propose an alternative explanation of their data. It is well established that the reporting of menstrual history is not wholly reliable; it varies, for example, with duration of time from conception to the onset of prenatal care.’ It has been estimated that between one-fourth and one-third of all infants classified as premature based on menstrual data are not premature.3-5 Estimation of gestational age is most likely to be inaccurate in women with long or irregular menstrual cycles6 The estimated associationbetween two variables will be diminished to the extent that one (or both) are inaccurately reported. One may assumethat the reporting of sex is accurate. But if the reliability of reporting last menstruation varies in different categories of women, then the result reported by Cooperstock and Campbell would be expected. I suggest that the categories that they identify as having a diminished excessof male preterm births (black :l:omen and white women who were under 20 years old, educated for 12 or fewer years, unmarried) are just the categories in which the reporting would be expected to be lessreliable.
156
0029.7844/97/$17.00 PI1S0029-78~J,(96)00~~~1-1
5.
6.
M, Campbell J. Excess males in preterm birth: Interactions with gestational age, race, and multiple birth. Obstet Gynecol 1996;88:189-93. Boklage CE, Kirby CF, Zincone LH. Annual and subannual rhythms in human conception rates: 1. Effective correction and use of public record LMP dates. Int J Fertil 1992;37:74-81. Boyce A, Mayaux MJ, Schwartz D. Classical and true gestational postmaturity. Am J Obstet Gynecol 1976;125:911-4. Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm and postterm gestations. JAMA 1988;260:3306-8. Mimer RDG, Richards B. An analysis of birth weight by gestational age of infants born in England & Wales 1967-71. J Obstet Gynaecol Br Comm 1974;81:956-67. Berg AT, Bracken MB. Measuring gestational age: An uncertain proposition. Br J Obstet Gynaecol 1992;99:280-2.
iNote: This letter was sent to Dr. M. Cooperstock who failed to respond within the allotted time. Editorial
DIRECT
LAPAROSCOPIC
ENTRY
USING A SHARP AND DULL TROCAR TECHNIQUE To the Editor:
Most laparoscopic surgeons would disagree with Hasaniya et al’ that relying on tactile sensation is sufficient to retard the penetrating sharp trocar from imminent intra-peritoneal entry. Tenting the peritoneum with an advancing sharp trocar in 99.6% of cases without a partial or complete intra-abdominal entry is difficult to comprehend. Replacing the sharp trocar with a blunt one in the midst of a blind insertion process demands that the operator must be knowledgeable as to where the tip of the first trocar is located. This is not consistent with usual clinical practice. Our own published experience with the visually guided optical trocar indicated that in more than 50% of insertions as much as one-third of the sharp trocar tip may penetrate into the abdominal cavity before an anticipated loss of resistance can be appreciated by the surgeon.2 Of greatest concern is the fact that in more than one in ten instances, intra-abdominal placement of the trocar occurs without any corresponding tactile sensations.
Obstetrics & Gynecology
For this reason, we have repeatedly stressed that blind trocar insertions can only be theoretically improved if the surgeon has the ability to visually identify tissue layers before their contact by the penetrating instrument. This is the concept that was advanced by Kaali3 in the original design of the optical trocar. The recently introduced commercial optical trocar is known as Endopath Optiview (Ethicon Endosurgery, Cincinnati, OH). It has a transparent blunt conical tip with recessed plastic tissue separators and is complimented by a standard light telescope that provides videoderived direct visualization during the entire insertion process. This optical surgical obturator permits blunt dissection of various tissue layers in the abdominal wall under continuous visual guidance. When the peritoneum is penetrated the surgeon can verify proper intra-abdominal placement and minimize contact with vessels and bowel.
that could occur from direct entry with a sharp trocar. We agree that with our technique the sharp trocar may have entered the peritoneal cavity at a higher rate than we perceived, but more than 3000 laparoscopic procedures, including procedures performed on the 1655 patients in our study, have been performed in our center using the sharp and dull technique without a complication or failure. This allows us to conclude that this technique is a safe alternative to the Verres needle or the direct laparoscopic insertion technique. Thomas S. Kosasa,MD Department of Obstetrics and Gynecology University of Hawaii Johrz A. Burns School of Medicine and Kapiolani Medical Center for Women and Children 1319 Punahou Streef Honolulu. HI 96826
References Steven G. Kaali, MD David H. Barad, MD Albert Einstein College of Medicine Bronx, New York
References 1. Hasaniya NW, Kosasa TS, Shieh T, Nakayama RT. Direct laparoscopic entry using a sharp and dull trocar technique. Obstet Gynecol 1996;88:620-1. 2. Kaali SG, Barad DH, Merkatr IR. Comparison of visual and tactile localization of the trocar tip during abdominal entry. J Am Assoc Gynecol Laparosc 1994;2:75-7. 3. Kaali SG. Introduction of the Opti-Trocar. J Am Assoc Gynecol Laparosc 1993;1:50-3.
1. Copeland C, Wing R, Hulka JF. Direct trocar insertion at laparoscopy: An evaluation. Obstet Gynecol 1983;62:655-9. 2. Byron JW, Fujiyoshi CA, Miyazawa K. Evaluation of the direct trocar insertion technique at laparoscopy. Obstet Gynecol 1989;74: 423-5. 3. Kaali SG, Bartfai G. Direct insertion of the laparoscopic trocar after an earlier laparotomy. J Reprod Med 1985;33:739-40. 4. Hasaniya NW, Kosasa TS, Shieh T, Nakayama RT. Direct laparoscopic entry using a sharp and dull trocar technique. Obstet Gynecol 1996;88:620-1.
MEASURING
CONTRACEPTIVE
EFFECTIVENESS:
A
CONCEPTUAL
In reply:
We agree that advancing the sharp trocar until the peritoneum is tented may lead to inadvertent entry into the peritoneal cavity. This does not reduce the safety of the procedure becauseentry of the sharp trocar into the peritoneal cavity without prior pneumoperitoneum is a standard procedure in many centers,‘,’ and Kaali3 himself reported 1670 consecutive laparoscopies using direct entry with the sharp trocar. We stated that the sharp trocar is replaced with the dull trocar when the fascia is penetrated,” not after tenting of the peritoneum. Figure 1 of our paper identifies: initial insertion of the sharp trocar to penetrate the fascia. Unfortunately, the artist depicted the sharp trocar tenting the peritoneum rather than the fascia, which was discovered too late to be corrected. Insertion of the sharp trocar with a gradual twisting motion does, in our experience, allow the operator to feel when the fascia has been penetrated. Entry into the peritoneal cavity with the dull trocar has, in our experience, reduced the type of complication
VOL.
89, NO.
1, JANUARY
1997
FRAMEWORK To the Editor:
Steiner et al’ have made a valuable contribution toward the understanding of contraceptive effectiveness, but I wish to raise two concerns with their proposed definitions for efficacy and effectiveness. First, because both these definitions depend on estimates of the expected pregnancy rate for a given frequency and timing of intercourse, it is vital that the best possible data be used for the probability of pregnancy by cycle day. A highly relevant biologic marker for the probability of pregnancy on any given cycle day is the quality of the vaginal mucus discharge present on that day.‘s3 This discharge, which is highly correlated with cervical mucus production, not only provides information on the timing of ovulation, but also on the probability of sperm survival.4,5 Thus, future studies of effectiveness and efficacy should take into account vaginal mucus discharge patterns.
Letters
157
The Galton Laboratory University College London WolfsonHouse 4 Sfepkenson Way Londoz NW 1 2 HE England
Letters
References 1. Cooperstock
EXCESS MALES IN PRETERM
BIRTH: 2.
INTERACTIONS AGE,RACE,AND
WITH
GESTATIONAL
MULTIPLE
BIRTH
3. 4.
To tke Editor:
Cooperstock and Campbell1 note that the sex ratio (proportion male) of live births declines with duration of gestation (dated from reported last menstruation). They found that this associationis far more powerful in white than black births and, within white births, more powerful in those to married women, those to women aged more than 20 years, and those to women educated for 12 years or more. They write, “The excessof males [in preterm births] in selected groups suggests the existence of a mechanism of preterm birth influenced by fetal gender, “ and, “Preterm births in blacks and in twin gestations greater than 33 weeks may be more often due to alternative mechanismsthat are independent of fetal gender.” I propose an alternative explanation of their data. It is well established that the reporting of menstrual history is not wholly reliable; it varies, for example, with duration of time from conception to the onset of prenatal care.’ It has been estimated that between one-fourth and one-third of all infants classified as premature based on menstrual data are not premature.3-5 Estimation of gestational age is most likely to be inaccurate in women with long or irregular menstrual cycles6 The estimated associationbetween two variables will be diminished to the extent that one (or both) are inaccurately reported. One may assumethat the reporting of sex is accurate. But if the reliability of reporting last menstruation varies in different categories of women, then the result reported by Cooperstock and Campbell would be expected. I suggest that the categories that they identify as having a diminished excessof male preterm births (black :l:omen and white women who were under 20 years old, educated for 12 or fewer years, unmarried) are just the categories in which the reporting would be expected to be lessreliable.
156
0029.7844/97/$17.00 PI1S0029-78~J,(96)00~~~1-1
5.
6.
M, Campbell J. Excess males in preterm birth: Interactions with gestational age, race, and multiple birth. Obstet Gynecol 1996;88:189-93. Boklage CE, Kirby CF, Zincone LH. Annual and subannual rhythms in human conception rates: 1. Effective correction and use of public record LMP dates. Int J Fertil 1992;37:74-81. Boyce A, Mayaux MJ, Schwartz D. Classical and true gestational postmaturity. Am J Obstet Gynecol 1976;125:911-4. Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm and postterm gestations. JAMA 1988;260:3306-8. Mimer RDG, Richards B. An analysis of birth weight by gestational age of infants born in England & Wales 1967-71. J Obstet Gynaecol Br Comm 1974;81:956-67. Berg AT, Bracken MB. Measuring gestational age: An uncertain proposition. Br J Obstet Gynaecol 1992;99:280-2.
iNote: This letter was sent to Dr. M. Cooperstock who failed to respond within the allotted time. Editorial
DIRECT
LAPAROSCOPIC
ENTRY
USING A SHARP AND DULL TROCAR TECHNIQUE To the Editor:
Most laparoscopic surgeons would disagree with Hasaniya et al’ that relying on tactile sensation is sufficient to retard the penetrating sharp trocar from imminent intra-peritoneal entry. Tenting the peritoneum with an advancing sharp trocar in 99.6% of cases without a partial or complete intra-abdominal entry is difficult to comprehend. Replacing the sharp trocar with a blunt one in the midst of a blind insertion process demands that the operator must be knowledgeable as to where the tip of the first trocar is located. This is not consistent with usual clinical practice. Our own published experience with the visually guided optical trocar indicated that in more than 50% of insertions as much as one-third of the sharp trocar tip may penetrate into the abdominal cavity before an anticipated loss of resistance can be appreciated by the surgeon.2 Of greatest concern is the fact that in more than one in ten instances, intra-abdominal placement of the trocar occurs without any corresponding tactile sensations.
Obstetrics & Gynecology
For this reason, we have repeatedly stressed that blind trocar insertions can only be theoretically improved if the surgeon has the ability to visually identify tissue layers before their contact by the penetrating instrument. This is the concept that was advanced by Kaali3 in the original design of the optical trocar. The recently introduced commercial optical trocar is known as Endopath Optiview (Ethicon Endosurgery, Cincinnati, OH). It has a transparent blunt conical tip with recessed plastic tissue separators and is complimented by a standard light telescope that provides videoderived direct visualization during the entire insertion process. This optical surgical obturator permits blunt dissection of various tissue layers in the abdominal wall under continuous visual guidance. When the peritoneum is penetrated the surgeon can verify proper intra-abdominal placement and minimize contact with vessels and bowel.
that could occur from direct entry with a sharp trocar. We agree that with our technique the sharp trocar may have entered the peritoneal cavity at a higher rate than we perceived, but more than 3000 laparoscopic procedures, including procedures performed on the 1655 patients in our study, have been performed in our center using the sharp and dull technique without a complication or failure. This allows us to conclude that this technique is a safe alternative to the Verres needle or the direct laparoscopic insertion technique. Thomas S. Kosasa,MD Department of Obstetrics and Gynecology University of Hawaii Johrz A. Burns School of Medicine and Kapiolani Medical Center for Women and Children 1319 Punahou Streef Honolulu. HI 96826
References Steven G. Kaali, MD David H. Barad, MD Albert Einstein College of Medicine Bronx, New York
References 1. Hasaniya NW, Kosasa TS, Shieh T, Nakayama RT. Direct laparoscopic entry using a sharp and dull trocar technique. Obstet Gynecol 1996;88:620-1. 2. Kaali SG, Barad DH, Merkatr IR. Comparison of visual and tactile localization of the trocar tip during abdominal entry. J Am Assoc Gynecol Laparosc 1994;2:75-7. 3. Kaali SG. Introduction of the Opti-Trocar. J Am Assoc Gynecol Laparosc 1993;1:50-3.
1. Copeland C, Wing R, Hulka JF. Direct trocar insertion at laparoscopy: An evaluation. Obstet Gynecol 1983;62:655-9. 2. Byron JW, Fujiyoshi CA, Miyazawa K. Evaluation of the direct trocar insertion technique at laparoscopy. Obstet Gynecol 1989;74: 423-5. 3. Kaali SG, Bartfai G. Direct insertion of the laparoscopic trocar after an earlier laparotomy. J Reprod Med 1985;33:739-40. 4. Hasaniya NW, Kosasa TS, Shieh T, Nakayama RT. Direct laparoscopic entry using a sharp and dull trocar technique. Obstet Gynecol 1996;88:620-1.
MEASURING
CONTRACEPTIVE
EFFECTIVENESS:
A
CONCEPTUAL
In reply:
We agree that advancing the sharp trocar until the peritoneum is tented may lead to inadvertent entry into the peritoneal cavity. This does not reduce the safety of the procedure becauseentry of the sharp trocar into the peritoneal cavity without prior pneumoperitoneum is a standard procedure in many centers,‘,’ and Kaali3 himself reported 1670 consecutive laparoscopies using direct entry with the sharp trocar. We stated that the sharp trocar is replaced with the dull trocar when the fascia is penetrated,” not after tenting of the peritoneum. Figure 1 of our paper identifies: initial insertion of the sharp trocar to penetrate the fascia. Unfortunately, the artist depicted the sharp trocar tenting the peritoneum rather than the fascia, which was discovered too late to be corrected. Insertion of the sharp trocar with a gradual twisting motion does, in our experience, allow the operator to feel when the fascia has been penetrated. Entry into the peritoneal cavity with the dull trocar has, in our experience, reduced the type of complication
VOL.
89, NO.
1, JANUARY
1997
FRAMEWORK To the Editor:
Steiner et al’ have made a valuable contribution toward the understanding of contraceptive effectiveness, but I wish to raise two concerns with their proposed definitions for efficacy and effectiveness. First, because both these definitions depend on estimates of the expected pregnancy rate for a given frequency and timing of intercourse, it is vital that the best possible data be used for the probability of pregnancy by cycle day. A highly relevant biologic marker for the probability of pregnancy on any given cycle day is the quality of the vaginal mucus discharge present on that day.‘s3 This discharge, which is highly correlated with cervical mucus production, not only provides information on the timing of ovulation, but also on the probability of sperm survival.4,5 Thus, future studies of effectiveness and efficacy should take into account vaginal mucus discharge patterns.
Letters
157