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Dennen's Forceps Deliveries.pdf
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Natalya Lovitz
Dec 25, 2023, 4:52:58 PM12/25/23
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This volume retains much of the original text from the previous edition, including explanations of forceps devices and techniques. It also provides the latest College guidelines, a chapter on vacuum-assisted deliveries, and information on the current and changing status of forceps deliveries.
Dennen's Forceps Deliveries.pdf
Download File https://8itmenzhora.blogspot.com/?dtts=2wVLuA
processing.... Drugs & Diseases > Obstetrics & Gynecology Forceps Delivery Updated: Jun 15, 2020 Author: Michael G Ross, MD, MPH; Chief Editor: Christine Isaacs, MD more... Share Print Feedback Close Facebook Twitter LinkedIn WhatsApp Email webmd.ads2.defineAd(id: 'ads-pos-421-sfp',pos: 421); Sections Forceps Delivery Sections Forceps Delivery Overview Practice Essentials History of the Procedure Epidemiology Presentation Indications Relevant Anatomy Contraindications Show All Workup Treatment Preoperative Details Intraoperative Details Postoperative Details Follow-up Complications Outcome and Prognosis Future and Controversies Show All Media Gallery References Overview Practice Essentials Forceps are instruments designed to aid in the delivery of the fetus by applying traction to the fetal head. Many different types of forceps have been described and developed. Generally, forceps consist of 2 mirror image metal instruments that are maneuvered to cradle the fetal head and are articulated, after which traction is applied to effect delivery.
The credit for the invention of the precursor of the modern forceps to be used on live infants goes to Peter Chamberlen of England (circa 1600). Modifications have led to more than 700 different types and shapes of forceps. In 1745, William Smellie described the accurate application to the occiput, rather than the previously performed pelvic application, regardless of the position of the head. In 1845, Sir James Simpson developed a forceps that was designed to appropriately fit both cephalic curvatures and pelvic curvatures. In 1920, Joseph DeLee further modified that instrument and advocated the prophylactic forceps delivery. In an era in which many women labored and delivered under heavy sedation, forceps deliveries became common.
In current obstetrical practice, the use of forceps has become much less common. Clinical studies performed before the 1970s suggested that the risk of fetal morbidity and mortality was higher when the second stage of labor exceeded 2 hours. [1] With contemporary obstetrical management, morbidity rates no longer increase with longer labors if fetal surveillance is reassuring. Thus, the length of the second stage of labor alone is no longer an absolute indication for operative termination of labor, although it remains an indication in the American College of Obstetricians and Gynecologists (ACOG) publications. [2]
Other factors were also at work to decrease the use of forceps deliveries. In particular, the availability of blood products and greater choices in antibiotics helped make cesarean delivery a safe alternative to operative vaginal deliveries. In the 1980s, information became available suggesting that some forceps deliveries (midforceps deliveries) may be associated with an increased risk of fetal morbidity, though this issue remains controversial. These factors combined to greatly reduce the appeal of forceps delivery. Currently, many obstetrical training programs in North America struggle to teach forceps delivery. Problems include the lack of adequate personnel comfortable with teaching forceps-assisted vaginal deliveries, changes in consumer attitudes, and the demand for natural delivery. In addition, many practitioners fear litigation if a forceps-assisted delivery results in a poor outcome.
The frequency of operative vaginal deliveries is now estimated to be less than 5% of all vaginal deliveries. Most of these are vacuum deliveries with forceps deliveries comprising less than 1% of total deliveries. According to Bofill et al, trained fellows of the American College of Obstetricians and Gynecologists (ACOG) were more likely to be taught vacuum extraction, and they use vacuum extraction as their instrument of choice for operative vaginal deliveries. [3]
When forceps deliveries are performed, the Simpson forceps (see image below) is the instrument most commonly used for outlet- and low-forceps deliveries. Other types of forceps are also available; one specialized type is the Piper forceps, which is used in the delivery of the after-coming head in breech vaginal deliveries. It is designed to decrease traction on the fetal neck during breech delivery. Multiple other types of forceps have been designed to rotate the fetal head or for unusual maternal pelvic or fetal head shapes. For detailed information on other forceps procedures, the reader is directed to the book Dennen's Forceps Deliveries. [1]
Forceps delivery is classified according to the level and position of the head in the birth canal at the time the forceps are applied. In 1965, the ACOG issued a classification of low/outlet forceps, mid forceps, and high forceps. The low/outlet forceps categories were strictly defined and applied when the fetal scalp was visible or when the scalp had reached the pelvic floor, and only when the sagittal suture was in the anteroposterior diameter of the pelvis. In contrast, the category of mid forceps was very broad. It included many positions of the fetal head, and stations from engagement at zero station to the perineum.
When the safety of midforceps deliveries came into question in the 1980s, the ACOG redefined the classification of forceps deliveries to better define which procedures posed a significant fetal risk. [2] The revised classification uses the level of the leading bony point of the fetal head, in centimeters, measured from the level of the maternal ischial spines, to define station (-5 to 5 cm).
Outlet forceps: (1) The scalp is visible at the introitus, without separating the labia. The fetal skull has reached the pelvic floor. (2) The sagittal suture is in anteroposterior diameter, right or left occiput anterior or posterior position (ie, the fetal head is at or on the perineum and rotation does not exceed 45º).
Low forceps: The leading point of the fetal skull is at a station greater than or equal to +2 cm and is not on the pelvic floor. Low forceps deliveries without rotation are performed with a rotation of less than 45º; the procedure is described as beginning with rotation if the rotation is of more than 45º.
Mid forceps: The station is above +2 cm, but the head is engaged. Attempted vaginal deliveries from this station are rarely attempted and are associated with an increased rate of morbidity compared with Cesarean delivery in the second stage of labor. [4]
High forceps: This is not included in the classification. Previous systems classified high-forceps deliveries as procedures performed when the head is not engaged. High-forceps deliveries are not recommended.
Determination of the position is crucial in forceps application and traction. The fontanels and sutures are used to determine the position. The finding that the fontanels are not easily palpable is not uncommon; this may occur because of distortion, molding, or caput formation.
The era of modern operative obstetrics began with the invention of the forceps (Fig. 1) by Peter Chamberlen, Sr. Subsequently, over the years the ability to use forceps separated the obstetricians from the midwives. The use of forceps reached its acme in the United States as a result of the influence of DeLee, who in 1920 taught the importance of prophylactic forceps and episiotomy to protect against maternal and fetal injury.
"Detailed instruction in the use of the various types of obstetrical forceps is difficult to obtain. . . . A thorough knowledge of the advantages and disadvantages of the various types of forceps, and the techniques of their use will eliminate many of the bad results following blind faith in one type, or the 'trial and error method'. . . . A properly chosen and well-executed forceps delivery does not increase the risk of a bad result. Nor does the operator, in the average case, have to be one of exceptional skill, provided he has had detailed training in the use of forceps and knows his limitations."
In an attempt to evaluate the diminishing opportunity for trainee obstetricians to develop skills and knowledge in the techniques of midforceps delivery, Healy and Laufe6 sent questionnaires to 144 US and Canadian members of the Association of Professors of Obstetrics and Gynecology to survey residency training in the use of forceps. They analyzed 105 programs delivering approximately 283,000 women in 1981. All programs used outlet forceps, and all but one used midforceps. Significantly, staff obstetricians were present and instructing in the delivery room only 50% of the time in the United States, but in Canada a staff obstetrician was the principal instructor. Further, the mode of selection of the forceps most commonly used for midforceps and outlet forceps was habit and past experience, rather than design and function. Ironically, the authors of the study pointed out, two major postgraduate obstetrics texts devoted fewer than 2% of their pages to forceps delivery. Ramin and associates7 surveyed 295 US and Canadian residency programs; of these, 203 responded, representing 458,000 deliveries with results similar to those of Healy and Laufe.6 They did note, however, that institutions that performed midforceps deliveries did not have a decrease in their cesarean section rates. A study by Powell et al.8 in 2007 found that current training results in a substantial portion of residents graduating who do not feel competent to perform forceps deliveries and this affected their future operative delivery plans. Dennen1 emphasized detailed lectures about forceps, practice with mannequins, and supervision first in easy cases and later in more complicated ones to ensure proper training in the use of forceps.
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Dennen's Forceps Deliveries.pdf
Download File https://8itmenzhora.blogspot.com/?dtts=2wVLuA
processing.... Drugs & Diseases > Obstetrics & Gynecology Forceps Delivery Updated: Jun 15, 2020 Author: Michael G Ross, MD, MPH; Chief Editor: Christine Isaacs, MD more... Share Print Feedback Close Facebook Twitter LinkedIn WhatsApp Email webmd.ads2.defineAd(id: 'ads-pos-421-sfp',pos: 421); Sections Forceps Delivery Sections Forceps Delivery Overview Practice Essentials History of the Procedure Epidemiology Presentation Indications Relevant Anatomy Contraindications Show All Workup Treatment Preoperative Details Intraoperative Details Postoperative Details Follow-up Complications Outcome and Prognosis Future and Controversies Show All Media Gallery References Overview Practice Essentials Forceps are instruments designed to aid in the delivery of the fetus by applying traction to the fetal head. Many different types of forceps have been described and developed. Generally, forceps consist of 2 mirror image metal instruments that are maneuvered to cradle the fetal head and are articulated, after which traction is applied to effect delivery.
The credit for the invention of the precursor of the modern forceps to be used on live infants goes to Peter Chamberlen of England (circa 1600). Modifications have led to more than 700 different types and shapes of forceps. In 1745, William Smellie described the accurate application to the occiput, rather than the previously performed pelvic application, regardless of the position of the head. In 1845, Sir James Simpson developed a forceps that was designed to appropriately fit both cephalic curvatures and pelvic curvatures. In 1920, Joseph DeLee further modified that instrument and advocated the prophylactic forceps delivery. In an era in which many women labored and delivered under heavy sedation, forceps deliveries became common.
In current obstetrical practice, the use of forceps has become much less common. Clinical studies performed before the 1970s suggested that the risk of fetal morbidity and mortality was higher when the second stage of labor exceeded 2 hours. [1] With contemporary obstetrical management, morbidity rates no longer increase with longer labors if fetal surveillance is reassuring. Thus, the length of the second stage of labor alone is no longer an absolute indication for operative termination of labor, although it remains an indication in the American College of Obstetricians and Gynecologists (ACOG) publications. [2]
Other factors were also at work to decrease the use of forceps deliveries. In particular, the availability of blood products and greater choices in antibiotics helped make cesarean delivery a safe alternative to operative vaginal deliveries. In the 1980s, information became available suggesting that some forceps deliveries (midforceps deliveries) may be associated with an increased risk of fetal morbidity, though this issue remains controversial. These factors combined to greatly reduce the appeal of forceps delivery. Currently, many obstetrical training programs in North America struggle to teach forceps delivery. Problems include the lack of adequate personnel comfortable with teaching forceps-assisted vaginal deliveries, changes in consumer attitudes, and the demand for natural delivery. In addition, many practitioners fear litigation if a forceps-assisted delivery results in a poor outcome.
The frequency of operative vaginal deliveries is now estimated to be less than 5% of all vaginal deliveries. Most of these are vacuum deliveries with forceps deliveries comprising less than 1% of total deliveries. According to Bofill et al, trained fellows of the American College of Obstetricians and Gynecologists (ACOG) were more likely to be taught vacuum extraction, and they use vacuum extraction as their instrument of choice for operative vaginal deliveries. [3]
When forceps deliveries are performed, the Simpson forceps (see image below) is the instrument most commonly used for outlet- and low-forceps deliveries. Other types of forceps are also available; one specialized type is the Piper forceps, which is used in the delivery of the after-coming head in breech vaginal deliveries. It is designed to decrease traction on the fetal neck during breech delivery. Multiple other types of forceps have been designed to rotate the fetal head or for unusual maternal pelvic or fetal head shapes. For detailed information on other forceps procedures, the reader is directed to the book Dennen's Forceps Deliveries. [1]
Forceps delivery is classified according to the level and position of the head in the birth canal at the time the forceps are applied. In 1965, the ACOG issued a classification of low/outlet forceps, mid forceps, and high forceps. The low/outlet forceps categories were strictly defined and applied when the fetal scalp was visible or when the scalp had reached the pelvic floor, and only when the sagittal suture was in the anteroposterior diameter of the pelvis. In contrast, the category of mid forceps was very broad. It included many positions of the fetal head, and stations from engagement at zero station to the perineum.
When the safety of midforceps deliveries came into question in the 1980s, the ACOG redefined the classification of forceps deliveries to better define which procedures posed a significant fetal risk. [2] The revised classification uses the level of the leading bony point of the fetal head, in centimeters, measured from the level of the maternal ischial spines, to define station (-5 to 5 cm).
Outlet forceps: (1) The scalp is visible at the introitus, without separating the labia. The fetal skull has reached the pelvic floor. (2) The sagittal suture is in anteroposterior diameter, right or left occiput anterior or posterior position (ie, the fetal head is at or on the perineum and rotation does not exceed 45º).
Low forceps: The leading point of the fetal skull is at a station greater than or equal to +2 cm and is not on the pelvic floor. Low forceps deliveries without rotation are performed with a rotation of less than 45º; the procedure is described as beginning with rotation if the rotation is of more than 45º.
Mid forceps: The station is above +2 cm, but the head is engaged. Attempted vaginal deliveries from this station are rarely attempted and are associated with an increased rate of morbidity compared with Cesarean delivery in the second stage of labor. [4]
High forceps: This is not included in the classification. Previous systems classified high-forceps deliveries as procedures performed when the head is not engaged. High-forceps deliveries are not recommended.
Determination of the position is crucial in forceps application and traction. The fontanels and sutures are used to determine the position. The finding that the fontanels are not easily palpable is not uncommon; this may occur because of distortion, molding, or caput formation.
The era of modern operative obstetrics began with the invention of the forceps (Fig. 1) by Peter Chamberlen, Sr. Subsequently, over the years the ability to use forceps separated the obstetricians from the midwives. The use of forceps reached its acme in the United States as a result of the influence of DeLee, who in 1920 taught the importance of prophylactic forceps and episiotomy to protect against maternal and fetal injury.
"Detailed instruction in the use of the various types of obstetrical forceps is difficult to obtain. . . . A thorough knowledge of the advantages and disadvantages of the various types of forceps, and the techniques of their use will eliminate many of the bad results following blind faith in one type, or the 'trial and error method'. . . . A properly chosen and well-executed forceps delivery does not increase the risk of a bad result. Nor does the operator, in the average case, have to be one of exceptional skill, provided he has had detailed training in the use of forceps and knows his limitations."
In an attempt to evaluate the diminishing opportunity for trainee obstetricians to develop skills and knowledge in the techniques of midforceps delivery, Healy and Laufe6 sent questionnaires to 144 US and Canadian members of the Association of Professors of Obstetrics and Gynecology to survey residency training in the use of forceps. They analyzed 105 programs delivering approximately 283,000 women in 1981. All programs used outlet forceps, and all but one used midforceps. Significantly, staff obstetricians were present and instructing in the delivery room only 50% of the time in the United States, but in Canada a staff obstetrician was the principal instructor. Further, the mode of selection of the forceps most commonly used for midforceps and outlet forceps was habit and past experience, rather than design and function. Ironically, the authors of the study pointed out, two major postgraduate obstetrics texts devoted fewer than 2% of their pages to forceps delivery. Ramin and associates7 surveyed 295 US and Canadian residency programs; of these, 203 responded, representing 458,000 deliveries with results similar to those of Healy and Laufe.6 They did note, however, that institutions that performed midforceps deliveries did not have a decrease in their cesarean section rates. A study by Powell et al.8 in 2007 found that current training results in a substantial portion of residents graduating who do not feel competent to perform forceps deliveries and this affected their future operative delivery plans. Dennen1 emphasized detailed lectures about forceps, practice with mannequins, and supervision first in easy cases and later in more complicated ones to ensure proper training in the use of forceps.
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