Obesity and the practice of oral and maxillofacial surgery

Vol. 98 No. 1 July 2004

ORAL AND MAXILLOFACIAL SURGERY

Editor: James R. Hupp

Obesity and the practice of oral and maxillofacial surgery Robert D. Marciani, DMD,a Barry F. Raezer, BS,b and Hendra L. Marciani, BA, MA,c Cincinnati, Ohio UNIVERSITY OF CINCINNATI Objectives. Obesity is a disease that affects approximately 51 million Americans. The purpose of this paper is to establish the frequency of overweight and obese patients in an urban inner city oral and maxillofacial surgery (OMS) center, to provide an overview of the commonly applied standards and methods of establishing obesity, and to discuss the clinical and surgical implications that obesity has on the dispensing of office oral and maxillofacial surgical and anesthetic care. Study design. Consecutive patients presenting with oral and maxillofacial health needs were routinely screened for sex, age, blood pressure, pulse, height, and weight. Body Mass Index (BMI) was calculated in pounds using a standard mathematical formula for adults. Comparative statistical methods were used to depict the data. Results. The study included 520 patients. The average age of all patients was 34.55 years, average height was 66.58 inches, and average weight was 176.71 lbs with an average BMI of 28.5. One hundred ninety-four females (67%) were recorded as overweight and 130 females (45%) were recorded as obese (BMI > 30). Fewer males were overweight (55%) or obese (25%). Conclusions. Sixty-five percent of the patients observed in this study were judged as overweight or obese compared to a national average of 61%. Females of all ages were more likely to be overweight or obese compared to males. The complexities of treating a substantial number of obese patients in an OMS practice deserve more study. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:10-5)

Obesity is a disease that affects approximately 51 million Americans. Another 69 million Americans are considered to be overweight including at least 1 in 5 children.1,2 The prevalence of overweight and obese Americans has prompted the US Department of Health and Human Services to establish excessive weight as a ‘‘neglected health problem.’’3 Fully 33% to 40% of the potential patient population for Oral and Maxillofacial Surgeons (OMS) in the United States present with a serious disease that is a leading cause of unnecessary deaths and that

a

Chief, Division OMFS, Professor of Surgery, University of Cincinnati, Ohio. b Administrative Resident, Department of Surgery, University of Cincinnati. c Research Assistant, Division of Oral Maxillofacial Surgery, University of Cincinnati. Received for publication Sept 30, 2003; returned for revision Nov 19, 2003; accepted for publication Dec 23, 2003. 1079-2104/$ - see front matter
2004 Elsevier Inc. All rights reserved. doi:10.1016/j.tripleo.2003.12.026

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increases the risk of illness from about 30 significant medical conditions.4 The obese patient population presents unique anatomical, physiological, and perioperative challenges that must be studied and understood by all members of the surgical team. Obesity is a chronic condition that is strongly influenced by genetics, diet, sociological factors, and physical activity. Scientific evidence has established a strong relationship between obesity and a minimum of 15 conditions that, left untreated, contribute to early death. Weight loss of a modest 10% of body weight in an overweight patient can improve some obesity-related medical conditions including diabetes and hypertension. Other obesity-related medical conditions include coronary artery disease, cardiovascular disease, osteoarthritis, rheumatoid arthritis, and cancers (breast, esophagus and gastric, cardiac, colorectal, endometrial, renal cell).5 Researchers at the Centers for Disease Control and Prevention (CDC) estimated that as many as 47 million Americans may exhibit a cluster of medical conditions (a metabolic syndrome) characterized by insulin resistance and the presence of obesity, abdominal fat, high blood

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sugar and triglycerides, high blood cholesterol, and high blood pressure.6 The purpose of this paper is to establish the frequency of overweight and obese patients in an urban inner city OMS practice, to provide an overview of the commonly applied standards and methods of establishing obesity, and to discuss the clinical and surgical implications that obesity has on the delivery of office oral and maxillofacial surgical and anesthetic care. Obesity is defined as an excessively high amount of body fat or adipose tissue in relation to lean body mass. Adiposity or the amount of body fat and the distribution of the fat tissue deposits throughout the body are measures of obesity. Body fat distribution can be measured by calculating skin fold mass or waist-to-hip circumference ratios. More precise estimations of body fat quantity and location are obtainable with ultrasound, magnetic resonance imaging, or computed tomography. Overweight refers to increased body weight when correlated to height and compared to a standard of acceptable or desirable weights. Being overweight is not always related to excessive fat deposits. A wellconditioned athlete with a lean muscular body and very little body fat may weigh more than a nonathlete of the same height with more adipose tissue. The athlete’s larger muscle mass qualifies him by existing charts as ‘‘overweight’’ but not necessarily ‘‘over fat.’’ Desirable weight standards are commonly established by summarizing population averages and by a mathematical formula known as Body Mass Index (BMI). BMI expresses the relationship (or ratio) of weight to height. A simple mathematical formula is used to calculate BMI. A person’s body weight in kilograms or pounds is divided by the square of his or her height in meters or inches. The English BMI Formula for adults is BMI = (Weight in pounds ‚ height in inches ‚ height in inches) 3 703. The Metric BMI Formula is BMI = (Weight in kilograms ‚ height in cm ‚ height in cm) 3 10 000. A person weighing 273 pounds who is 70 inches tall would have a BMI = 39.1 (273 pounds divided by 70 inches divided by 70 inches multiplied by 703). Individuals with a BMI of 25 to 29.9 are considered overweight. A BMI of 30 or more by existing common standards would characterize an individual as obese. Morbid obesity is defined by a BMI of greater than 40, or between 35 and 40 when other medical conditions such as high blood pressure and diabetes are present. Waist Circumference is easily measured with a tape measure that is positioned around the smallest area below the rib cage and above the umbilicus. Excess abdominal fat out of proportion to total body fat is considered an independent predictor of risk factors and ailments associated with obesity. Women who are at risk

Marciani, Raezer, and Marciani 11

have a waist measurement greater than 35 inches. Men with waist measurements of 40 inches or more are also more likely to be afflicted with obesity-related ailments. Waist circumference standards used for the general population may not apply when a person is less than 5 feet in height or has a BMI of 35 or above. Waist-To-Hip Ratio (WHR) can be mathematically calculated by dividing the waist circumference by the hip circumference. Hip circumference is measured with a tape measure that comfortably calculates the distance around the largest extension of the buttocks. Persons carrying more weight around their middle encounter more health risks than subjects carrying extra weight around their hips or thighs. MATERIALS AND METHODS Consecutive patients presenting to the Oral and Maxillofacial Surgery Center at the University of Cincinnati over a 4-month period were routinely screened for sex, age, blood pressure, pulse, temperature, height, and weight. Patients reported their sex, height, and age. An automated monitor measured blood pressure and pulse. Oral temperature was obtained using a singleuse clinical thermometer registering in degrees Fahrenheit. Patients were weighed in pounds on a Detecto high-capacity portable digital scale (Cardinal Scale Manufacturing Co, PO Box 151 Webb City, Mo) specifically designed for obese and unsteady patients (maximum capacity 600 pounds). BMI was calculated in pounds using a standard mathematical formula for adults. Patients were included in the study when their height, weight, age, and sex were documented. Comparative statistical methods were used to depict the data. RESULTS Five hundred twenty patients were included in the study. Two hundred thirty-one subjects were male and 289 were female. The average age for all patients was 34.55 years, average height was 66.58 inches, average weight was 176.71 pounds, and average BMI was 28.5. The median BMI for all patients was 27 (Table I). One hundred ninety-four females (67%) were recorded as overweight (BMI equal to or greater than 25) compared to 55% of the males (Tables II and III). One hundred thirty females (45%) were recorded as obese (BMI equal to or greater than 30) (Table IV). Sixty males (25%) were categorized as obese (Table V). Forty-eight females (17%) had a BMI of 40 or greater compared to 6 males (2%). Females 21 to 40 years of age and 41 to 60 years of age had the highest median BMI when subjects were considered by age. The heaviest female weighed 372 pounds with a BMI of 65. The heaviest male weighed 420 pounds with a BMI of 57. The oldest patient was a 96-year-old female who weighed 190 pounds with

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Table I. Age, weight, height, pulse, temperature, and body mass index of all patients included in the study. Average SD Median Max Min Count

Age

Weight

Height

Sys

Dia

Pulse

T

BMI

34.55 15.05 32.00 96.00 4.00 553

176.71 53.83 168.20 420.20 17.40 552

66.58 4.47 67.00 77.00 36.00 533

130.25 21.91 128.00 226.00 86.00 533

76.68 14.79 75.00 181.00 27.00 553

76.02 13.17 75.00 133.00 36.00 552

97.92 1.01 98.00 101.60 92.60 509

28.45 8.11 27.00 65.00 14.00 520

Sys, systolic; Dia, diastolic; T, temperature; BMI, body mass index.

Table II. Composite data for all females with BMI > 25. Average SD Median Max Min Count

Age

Weight

Height

Sys

Dia

Pulse

T

BMI

36.45 15.41 33.50 96.00 15.00 192

205.40 50.63 190.30 372.20 137.60 194

64.49 3.14 64.00 74.00 50.00 194

132.42 21.46 128.00 226.00 93.00 191

78.59 15.08 77.00 181.00 49.00 191

79.59 12.40 78.00 120.00 49.00 191

98.00 1.00 98.20 99.80 94.20 181

34.56 7.72 32.90 65.00 25.00 194

BMI, body mass index; Sys, Systolic; Dia, diastolic; T, temperature.

Table III. Composite data for all males with BMI > 25. Average SD Median Max Min Count

Age

Weight

Height

Sys

Dia

Pulse

T

BMI

36.71 13.72 35.00 77.00 5.00 128

205.76 43.57 203.80 420.20 45.60 128

68.99 4.73 70.00 77.00 36.00 128

138.94 22.35 136.00 218.00 97.00 127

79.91 13.75 79.00 119.00 45.00 127

73.96 12.76 72.00 108.00 45.00 126

97.97 0.91 97.80 101.60 96.20 114

30.37 5.33 29.00 57.00 25.00 128

BMI, Body mass index; Sys, systolic; Dia, diastolic; T, temperature.

Table IV. Composite data for all females with BMI > 30. Average SD Median Max Min Count

Age

Weight

Height

Sys

Dia

Pulse

T

BMI

36.87 16.03 35.00 96.00 15.00 129

226.86 48.40 220.70 372.20 145.60 130

64.55 3.40 64.00 74.00 50.00 130

134.21 21.18 132.00 226.00 93.00 128

78.75 15.65 77.50 181.00 49.00 128

80.71 12.89 79.50 120.00 49.00 128

98.04 0.93 98.20 99.80 94.20 121

38.11 7.06 36.25 65.00 30.00 130

BMI, Body mass index; Sys, systolic; Dia, diastolic; T, temperature.

a BMI of 37. No significant abnormalities in blood pressure, pulse, or temperature were observed in the majority of subjects. DISCUSSION Perioperative considerations Overweight and obese patients present the OMS with anesthetic, surgical, practice ergonomics, and potential postoperative problems that distinguish heavy patients

from other patient cohorts. The operative team must be alert to the increased potential for airway obstruction, poor surgical visibility and accessibility, and the influence of intercurrent diseases on intraoperative and postoperative outcomes. Overweight and obese patients are not compatible with standard size office equipment (surgical chairs, monitoring cuffs, wheel chairs) that are designed for smaller patients. Patient flow in the ambulatory setting may be disrupted when slow moving, physically impaired patients with poor IV access sites

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Table V. Composite data for all males with BMI > 30. Average St. Dev Median Max Min Count

Age

Weight

Height

Sys

Dia

Pulse

T

BMI

40.50 12.54 38.50 77.00 14.00 60

233.01 42.91 222.50 420.20 141.00 60

68.89 3.99 69.00 76.50 50.00 60

143.63 23.36 140.00 218.00 104.00 60.00

81.97 13.07 80.50 112.00 56.00 60

77.03 12.64 75.00 108.00 53.00 60

97.97 0.83 97.80 99.80 96.20 52

34.60 4.97 33.50 57.00 30.00 60

BMI, body mass index; Sys, systolic; Dia, diastolic; T, temperature.

inordinately intrude on efficient care giving. Establishing key historical and physical examination findings will help the operative team decide on the appropriateness of outpatient care in the private office setting (Table VI). Establishing the diagnosis of an obstructive sleep disorder is a salient historical indicator of potential airway problems in patients undergoing conscious sedation or deep sedation anesthesia for oral surgical care in the private office setting. Many adult patients afflicted with sleep disorders are overweight and should be identified as much higher anesthetic risks. Surgeons should be increasingly more cautious scheduling heavy patients for conscious and deep sedation when oropharyngeal examination indicates that the base of the tongue obliterates visualization of the palatal arches (Mallampati III) and the planned surgery is expected to contribute to airway obstruction (eg, large mandibular tori reduction surgery). The presence of cardiac and pulmonary risk factors further heightens the potential for a difficult surgery and increasingly problematic anesthesia outcomes. Morbid obesity (MO) has been associated with increased pulmonary atelectasis after general anesthesia in patients anesthetized for laparoscopic gastroplasty when compared to nonobese patients being treated for laparoscopic cholecystectomy.7 Pulmonary atelectasis was assessed by computed tomography before the induction of general anesthesia, immediately after tracheal extubation, and 24 hours later. MO patients had more atelectasis expressed in the percentage of the total lung area than nonobese patients (2.1% versus 0%, respectively; P\.01). Atelectasis increased in both groups of patients after tracheal extubation but remained significantly more extensive in the MO group (7.6% for the MO patients versus 2.8% for the nonobese; P\.05) Atelectasis remained unchanged for at least 24 hours in MO patients but complete resolution was observed in the nonobese patients (9.7% versus 1.95, respectively; P\.01). Practice management considerations Overweight and obese patients tend to be less mobile, may depend on wheelchair transportation, and may pose a challenge to establish peripheral intravenous access. MO trauma patients have an 8-fold increase in mortality

Table VI. Key historical and physical examination findings predictive of a potential airway problem. Obstructive sleep patterns Cardiopulmonary disease with associated respiratory problems Breathing patterns and their relationship to body positioning Degree of patient mobility and exercise tolerance Tongue size and position Oropharyngeal airway opening Neck size and length Class II skeletal malocclusions Mandibular hypoplasia and severe retrognathia

rates among victims of blunt trauma.8 Diagnostic and treatment procedures performed in the field and hospital must be modified. Selected diagnostic procedures or treatments cannot be performed in the average hospital environment for the obese patient. Perioperative personnel must modify operating room routines to facilitate trauma care. Patients in excess of 300 pounds generally do not fit well into standard OMS operative chairs and their weight and girth may easily exceed the manufacturer’s weight limitations for motorized chair functions. Transferring patients following anesthesia may invite injury to both the patient and members of the operating team. In aggregate, the routine logistics of seating, preparing, treating, and discharging patients may substantially increase the time and resources necessary to meet the obese patient’s needs. Loss of practice efficiency translates into economic disadvantages for the surgeon that unfortunately adds another important issue to the business side of oral and maxillofacial health care. Intraoperative considerations Inherent to the safe and effective practice of surgery is the surgeon’s ability to visualize and have ready access to the surgical site. Operations are more likely to proceed smoothly when the surgical team is comfortably positioned around the patient. Ten MO individuals were retrospectively reviewed to determine the technical problems and incidence of surgical complications associated with knee joint arthroscopy.9 When compared to a cohort of patients of normal weight that were matched for age, sex, and surgical procedure, the MO patients had

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14 Marciani, Raezer, and Marciani longer operative times (P\.02). The authors reported that larger patients could not be accommodated by standard equipment creating technical problems. A greater number of arthroscopy portals to ensure a thorough examination were necessary. Poor posture and excessive twisting and reaching, added to poor visibility, translates into increased risk of surgical misadventures, increased operating time, and physical and mental stress on the OMS surgical team. Shorter team members are particularly disadvantaged. Taller, obese patients with wide shoulders and long torsos present the greatest surgical access challenge in the office environment.

Postoperative complications Obesity is considered a risk factor for increased complications in cardiothoracic and transplant surgery.10,11 Obese patients undergoing breast reconstruction with free transverse rectus abdominis myocutaneous flaps had significantly higher total flap loss and other complications compared to normal-weight patients.12 Total knee arthroplasty in MO patients is associated with an increase rate of perioperative complications including problems with wound healing, infection, and avulsion of the medial collateral ligament.13 Blood loss at total hip replacement is reported to be greater in obese patients compared to nonobese patients.14 Obesity as a risk factor for postoperative complications following an oral and maxillofacial surgical procedure has not been widely studied in the United States and is the subject for future investigations. Obesity is clearly one of the most important public health problems affecting both adults and children in the United States. When compared to the population of adults in the United States, the cohort studied in this investigation was obese at greater frequency (38% versus 26%) than the national average. Women were more often obese and/or overweight than men. These findings are consistent with reports of obesity and hypertension in a population of African-American patients undergoing surgery in another urban center.15 Obesity was present in 58% of the women and 23% of the men. Race was not identified in the methods of the Cincinnati study. More than 50% of the patient population seeking treatment at the OMS Center are African Americans. Findings from a third urban center studying maternal obesity concluded that obesity complicating pregnancy had increased significantly over the past 15 years particularly among African-American women.16 A comparative study of the prevalence of obesity in surgical patients at urban centers in the United States and Australia reported more obesity in the American cohort than their Australian counterparts.17

A greater proportion of women were found to be obese or morbidly obese in both hospitals. CONCLUSIONS Overweight and obese patients are at increased risk for anesthesia and surgery complications that can adversely affect surgical outcomes in a gamut of elective, urgent, and emergent treatments. Reports translating these risks to the oral and maxillofacial surgery patient in the ambulatory setting are scant. With appropriate perioperative precautions and monitoring, the incidence of serious cardiovascular and pulmonary complications can be minimized. Obese patients scheduled for traditional oral and maxillofacial surgery in an office setting can be safely and efficiently treated by incorporating the following measures into the office practice: (1) allow the patient more time to arrive and leave the office, (2) establish the ease of intravenous access during the consultation visit, (3) simulate the anticipated surgical procedure to establish the visibility and accessibility the surgical team can expect during the actual surgery, (4) avoid surgical procedures that contribute to airway obstruction, (5) use correct-sized monitoring equipment, (6) administer ‘‘slow and low’’ conscious sedation, (7) have recovery in the surgical suite to avoid nonpatientassisted transfer, and (8) provide oversized wheelchair transport out of the office. Patients who have serious pulmonary and/or cardiovascular disease requiring deep sedation or general anesthesia or need a surgical procedure that portends poor surgical access should be considered for a nonoffice operating suite venue.

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OOOOE Volume 98, Number 1 9. Berg EE. Knee joint arthroscopy in the morbidly obese. Arthroscopy 1999;15(2):321-4. 10. Birkmeyer NJ, Charlesworth DC, Hernandez F, Leavitt BJ, Marrin CA, Morton JR, et al. Obesity and risk of adverse outcomes associated with coronary artery bypass surgery. Circulation 1998;17:1689-94. 11. Drafts HH, Anjum MR, Wynn JJ, Mulloy LL, Bowley JN, Humphries AL. Ask the experts—Obesity surgery in renal transplantation. Clin Transplant 1997;11:493-6. 12. Chang DW, Wang B, Robb GL, Reece GP, Miller MJ, Evan RD, et al. Effect of obesity on flap and donor-site complications in free transverse rectus abdominus myocutanteous flap breast reconstruction. Reconstructive Surg 2000;105:2374-80. 13. Winiarsky R, Barth P, Lotke P. Total knee arthroplasty in morbidly obese patients. J Bone Joint Surg Am 1998;80:1770-4. 14. Bowditch MG, Villar RN. Do obese patients bleed more? A prospective study of blood loss at total hip replacement. Ann R Coll Surg Engl 1999;81:98-200.

Marciani, Raezer, and Marciani 15 15. Lord CO. Hypertension and obesity in African-American patients undergoing surgery. J Natl Med Assoc 1997;89:512-6. 16. Ehrenberg HM, Dierker L, Milluzi, Mercer BM. The prevalence of maternal obesity in an urban center. Am J Obstet Gynecol 2002;187:1189-93. 17. Riley RH, Burke V. Prevalence of obesity in surgical patients: a comparative survey in the United States and Australia. J Qual Clin Pract 1997;17:147-54. Reprint requests: Robert D. Marciani, DMD Chief Division OMFS Department of Surgery University of Cincinnati 231 Albert B. Sabin Way Cincinnati, OH 45267-0528. [email protected]