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Figure 1.
Area of the cutaneous paddle transferred with the rectus abdominis flap.

Area of the cutaneous paddle transferred with the rectus abdominis flap.

Figure 2.
Comparison of the radiologic atelectasis score between control patients and patients undergoing rectus abdominis flap reconstruction.

Comparison of the radiologic atelectasis score between control patients and patients undergoing rectus abdominis flap reconstruction.

Figure 3.
Comparison of radiologic atelectasis categories between control patients and patients undergoing rectus abdominis flap reconstruction.

Comparison of radiologic atelectasis categories between control patients and patients undergoing rectus abdominis flap reconstruction.

Figure 4.
Comparison of the atelectasis score between patients with large and small rectus abdominis flaps.

Comparison of the atelectasis score between patients with large and small rectus abdominis flaps.

1.
Seikaly  HKuzon Jr  WMGullane  PFHerman  SJ Pulmonary atelectasis after reconstruction with pectoralis major flaps. Arch Otolaryngol Head Neck Surg.1990;116:575-577.
2.
Schuller  DEDaniels  RLKing  MHouser  S Analysis of frequency of pulmonary atelectasis in patients undergoing pectoralis major musculocutaneous flap reconstruction. Head Neck.1994;16:25-29.
3.
Wax  MKHurst  J Pulmonary atelectasis after reconstruction with a latissimus dorsi myocutaneous flap. Laryngoscope.1996;106:268-272.
4.
Rigg  JRA Pulmonary atelectasis after anesthesia: pathophysiology and management. Can Anaesth Soc J.1981;28:305-313.
5.
Rao  MKReilley  TESchuller  DEYoung  DC Analysis of risk factors for postoperative pulmonary complications in head and neck surgery. Laryngoscope.1992;102:45-57.
Original Article
March 2002

Pulmonary Atelectasis After Reconstruction With a Rectus Abdominis Free Tissue Transfer

Author Affiliations

From the Departments of Otolaryngology/Head and Neck Surgery, Oregon Health Sciences University, Portland (Drs Wax, Rosenthal, Cohen, and Andersen and Mr Takaguchi), and the University of Washington, Seattle (Dr Futran).

Arch Otolaryngol Head Neck Surg. 2002;128(3):249-252. doi:10.1001/archotol.128.3.249
Abstract

Background  Atelectasis is one of the most common postoperative complications encountered in head and neck surgery. Risk factors include preexisting pulmonary disease, the procedure performed, and the length of anesthetic. Regional flaps used to reconstruct defects in the head and neck predispose to radiographic atelectasis. The rectus abdominis myocutaneous flap is usually transferred as a free tissue transfer. Harvesting the flap results in abdominal wall pain and postoperative splinting that may contribute to an increased development of atelectasis. To our knowledge, this issue has not been previously examined.

Design  Retrospective review.

Results  Fifty-three patients underwent rectus abdominis myocutaneous free flap reconstruction following major ablative procedures for head and neck cancer. The flap size ranged from 5 × 7 to 25 × 27 cm. Most flaps were 8 × 15 cm. The cutaneous area transferred ranged from 35 to 600 cm2 (mean, 120 cm2). These patients were compared with a group of 53 patients who were matched for age, sex, length of the procedure, and stage of disease. Postoperative atelectasis was radiographically detected in 37 (70%) of the patients who underwent rectus abdominis myocutaneous free flap reconstruction vs 41 (77%) of the controls. Major atelectasis was not encountered in any patient in either group. Patients with a larger cutaneous paddle (>120 cm2) had a higher atelectasis score than patients with smaller cutaneous paddles (≤120 cm2) (P = .02).

Conclusions  The incidence of radiographic postoperative atelectasis in patients undergoing rectus abdominis myocutaneous free tissue transfer is high. The degree of atelectasis is small, and the clinical correlation and relevance are minimal.

ONE OF the most common postoperative complications in head and neck oncologic surgery is pulmonary atelectasis.1 Intraoperative mechanical ventilation, combined with respiratory depression from narcotics, contributes to pooling of pulmonary secretions.1,2 To our knowledge, the incidence of pulmonary atelectasis in patients undergoing head and neck surgery has not been well characterized. Radiographic atelectasis has been demonstrated in 20% to 80% of patients, with major atelectasis being recorded in 1% to 10% of the patients.13 Reconstruction of head and neck oncologic ablative defects often entails transfer of regional myocutaneous flaps. If these flaps are based on the chest wall, then splinting to diminish incisional pain may be a contributing factor for atelectasis. Smoking history, duration of anesthetic, age, and types of surgery are also considered to be risk factors.4,5 Seikaly et al1 reported that a pectoralis major myocutaneous flap may increase the frequency of postoperative pulmonary atelectasis. In contrast, Schuller et al2 contradicted this and found no increased incidence of clinically relevant atelectasis in their patients undergoing pectoralis major myocutaneous flap reconstruction. Wax and Hurst3 compared patients with latissimus dorsi myocutaneous flaps with a control group and found a high rate of radiologic atelectasis but no difference among the groups. Patients with large cutaneous paddles had significantly more radiographic atelectasis than patients with smaller cutaneous paddles. The clinical relevance was not established.

The advent of free tissue transfer has seen the pectoralis major and pedicled latissimus dorsi myocutaneous flaps replaced by other composite tissues. The rectus abdominis myocutaneous free flap is frequently transferred to the head and neck as a free tissue transfer. In our practice, it is the most common myocutaneous tissue used in head and neck reconstruction.

Mobilization and harvesting of a rectus abdominis flap entail a large abdominal incision from the zyphoid process to the pubis. Large skin paddles are harvested with the underlying rectus abdominis muscle. The anterior rectus sheath is harvested to a lesser extent. Closure is accomplished primarily with the fascia often being tight and the skin incision also being tight.

We hypothesized that the tight abdominal closure and associated abdominal pain may lead to significant splinting and possibly to a higher incidence of pulmonary atelectasis. We, therefore, examined our patients for the development of atelectasis postoperatively.

PATIENTS AND METHODS

Between January 1, 1999, and December 30, 2000, 53 patients underwent rectus abdominis myocutaneous flap reconstruction following a major ablative procedure for head and neck malignancy. Patients were retrospectively examined. An oncologic surgical resection was usually performed by a separate ablative team. Reconstruction was usually started once the defect size was known. This allowed for a 2-team approach. Twenty-six procedures were performed at Oregon Health Sciences University, Portland, with all reconstructions being performed by the same surgeon (M.K.W.). Twenty-seven procedures were done at the University of Washington, Seattle, with all reconstructions being performed by the same surgeon (N.F.). These patients were then matched to a pool of patients who had undergone similar head and neck oncologic and reconstructive procedures. Patients in the 2 groups were carefully matched for age, sex, site of the flap, stage of disease, and duration of anesthetic. The control group consisted of patients who underwent ablation and some form of reconstruction, usually involving a radial forearm or fibula osteocutaneous free flap. Patients with pectoralis major or latissimus dorsi myocutaneous flaps were eliminated from the control group. No patient in either group required repositioning. The total anesthetic time, maximum postoperative temperature in the first 24 hours, and size and site of the rectus abdominis myocutaneous flap were recorded. All patients with rectus abdominis myocutaneous flaps had primary fascial, as well as cutaneous, closure. Preoperative (posterior or anterior and lateral) and day 1 postoperative (portable) chest radiographs were reviewed by the radiologist, who was blinded to the patients' operative procedure. The patients' postoperative radiograph was assigned an atelectasis score based on the extent of atelectasis according to a previously described system:

The atelectasis category of none indicated a total atelectasis score of 0; minor, 1 to 5; and major, greater than 5. Statistical analysis of all atelectasis scores comparing flap with control groups was performed using the Spearman rank correlation coefficient. Comparison of atelectasis scores between those with large and small flaps in the control group was performed with a Mann-Whitney test. Comparisons of flap size (small, large, and control) and atelectasis category (nonminimal and major) were performed with a χ2 test. Significance was at the P= .05 level.

RESULTS

Of the 53 patients in this study group who underwent rectus abdominis myocutaneous flap reconstruction, all flaps were transferred as free tissue. The maximum temperature on the first postoperative day was similar in both groups. The mean anesthetic time was longer in the control group, but not significantly so (P = .9). All patients were smokers. Thirty-four had tracheotomies or laryngostomies. All patients undergoing flap reconstruction had stage III or IV disease. Previous treatment was similar between groups. The flap surface area ranged from 35 to 600 cm2 (mean, 120 cm2) (Figure 1). The flap size ranged from 5 × 7 to 25 × 27 cm (mean, 8 × 15 cm). This was a reflection of the size of the defects that needed to be reconstructed. The incidence of postoperative atelectasis in the control group was 41 (77%) of 53 patients. The corresponding figures for the flap group were 37 (70%) of 53 patients. No major atelectasis was seen in the patients undergoing flap reconstruction. There was no difference in the atelectasis scores and categories between patients with rectus abdominis myocutaneous flaps and patients in the control group (Figure 2 and Figure 3, respectively). Arbitrarily, flaps with skin paddles greater than 120 cm2 were considered large and were analyzed separately. Patients with large flaps demonstrated atelectasis 79% of the time compared with patients with smaller flaps, who demonstrated atelectasis 55% of the time. When comparing the atelectasis scores, patients with larger flaps had a significantly higher atelectasis score than did patients with smaller flaps (P = .02). The atelectasis category was also significantly greater in patients with larger flaps (P = .03) (Figure 4).

In patients with rectus abdominis myocutaneous flaps, there was no correlation between the side on which the flap was harvested and the side that developed the atelectasis. The presence of radiographic preoperative pulmonary disease could not be correlated or compared with postoperative atelectasis scores because of the small degrees of atelectasis observed. Variables in radiographic techniques (anterior or posterior and lateral) vs a portable film make direct comparison difficult.

COMMENT

The pectoralis major myocutaneous flap is the workhorse in the reconstruction of head and neck defects following ablation for head and neck cancers.13 Increasing use of free tissue transfer has allowed for more accurate replacement of composite tissue defects with like composite tissue. In cases in which large cutaneous paddles and tissue bulk are required, myocutaneous flaps are the reconstructive option of choice. In our institution, we have increasingly turned to the rectus abdominis myocutaneous flap in instances that require large skin surface area and tissue bulk.

Seikaly et al1 analyzed patients undergoing pectoralis major myocutaneous flap reconstruction, and they demonstrated a 70% radiographic incidence of pulmonary atelectasis in patients who did not undergo flap reconstruction. Major postoperative pulmonary atelectasis was evident in 5% of these patients. When Seikaly and colleagues looked at patients who had undergone pectoralis major myocutaneous flap reconstruction, they demonstrated that 75% of these patients showed evidence of major atelectasis. Sixty percent of patients with skin paddles larger than 40 cm2 had major atelectasis. Seikaly et al were unable to correlate clinical findings with radiographic observation, and they attributed their high incidence of atelectasis to the tight closure of the donor defect, which caused chest wall constriction and splinting.

Schuller et al2 compared 66 patients who did not undergo flap reconstruction with a group of 86 patients who underwent pectoralis major myocutaneous flap reconstruction. They correlated atelectasis with the same clinical atelectasis score. Of note, Schuller et al divided their patients into those with preexisting pulmonary disease (PEPD) and those without. They also attempted to correlate size of the flaps with atelectasis. Most patients in their series had flaps with a surface area greater than 40 cm2 (mean, 71 cm2). These flaps were considerably larger than those used by Seikaly et al.1 Patients with no flaps and no PEPD developed atelectasis 43.8% of the time compared with a 58.8% incidence in patients with PEPD. Major atelectasis developed in 6.3% of these patients. Patients with pectoralis major myocutaneous flaps developed atelectasis 36.6% of the time when there was no PEPD and 51.1% of the time when there was PEPD. Of these patients, 6.7% developed major atelectasis. Schuller et al2 were unable to demonstrate an increased incidence of pulmonary atelectasis with pectoralis major myocutaneous flap reconstruction; however, they found that patients with PEPD exhibited a higher rate of pulmonary atelectasis. They also were unable to correlate between larger flaps and pulmonary atelectasis.

Wax and Hurst3 looked at 18 patients undergoing latissimus dorsi myocutaneous flap reconstruction. Fourteen patients had pedicled flaps, while 4 had free tissue transfer. The mean size of the flap was 128 cm2, with more than half of the flaps being 150 or 225 cm2. Eighty-three percent of the patients in their series showed some sign of atelectasis, whereas 17% developed major atelectasis. Patients with larger flaps (>120 cm2) were significantly more likely to develop atelectasis than the control, or small paddle, group. In their study, Wax and Hurst demonstrated that patients with or without flaps did equally well. There was no correlation between the severity of radiologic atelectasis and clinical morbidity.

The previously described studies13 prompted us to look carefully at patients who underwent rectus abdominis myocutaneous free tissue transfer. The rectus abdominis myocutaneous flap provides substantial soft tissue bulk and cutaneous area. Closure is easy with the lax skin of the abdomen when compared with a pectoralis major myocutaneous flap. The ability to close large defects is similar to that of the latissimus dorsi, although it is our impression that the laxity of the abdominal wall provides for an easier closure than does the back skin of a latissimus dorsi flap.3 The rectus abdominis myocutaneous flap involves closure of the anterior rectus sheath. Because our technique uses a minimal harvest of the anterior sheath, we were able to close the defects of all of our patients without synthetic mesh. This often requires significant tension. The average size of the skin paddle in our series was 120 cm2. Paddles ranged from 35 to 600 cm2, and more than half of the flaps were 120 cm2. This compares with the mean size of the flap in the Schuller et al2 series of 71 cm2, the Seikaly et al1 series of less than 40 cm2, and the Wax and Hurst3 latissimus dorsi series of 128 cm2. Our overall incidence of radiographically detected postoperative atelectasis was 37 (70%) of 53 patients. No patient in our series developed major atelectasis. Only 5 patients had an atelectasis score of 3, which was still in the minor atelectasis range. When we compared patients with larger flaps (>120-cm2 skin paddles), there was a significant increase in the overall atelectasis score (79% vs 55%). However, the scores ranged between 1 and 3, which are considered minor. The clinical significance of this finding is questionable. Clinically, our patients with flaps and those in the control group did equally well. There was no difference in postoperative pneumonia, other pulmonary morbidity, or temperature. There was no correlation between the side from which the flap was harvested and the side on which the atelectasis developed.

The anesthetic time in our patient group was similar to that reported by Wax and Hurst3 in their review of latissimus dorsi myocutaneous flaps. In both instances, the average anesthetic time was significantly longer than the times found in the studies by Seikaly et al1 and Schuller et al,2 which involved pectoralis major myocutaneous flaps. This may help explain why a greater degree of atelectasis was present in patients undergoing rectus abdominis or latissimus dorsi myocutaneous flap reconstruction as opposed to pectoralis major flap reconstruction.

The severity of the patient's preoperative medical condition is an important factor in determining the degree of radiologic pulmonary atelectasis.2,4,5 The clinical relevance of this radiologic atelectasis is unknown. Preexisting pulmonary disease and chronic alcoholism were factors that contributed to major morbidity (pneumonia and prolonged ventilation) in our patient population. The minor degree of pulmonary atelectasis that developed in our patients postoperatively makes comparison and attempted analysis of the contribution of PEPD to the morbidity difficult. A larger prospective analysis with a comparable radiographic technique would be important. We would expect that PEPD had a more significant contribution to the development of postoperative pulmonary complications, as demonstrated by Schuller et al.2

In conclusion, the rectus abdominis myocutaneous flap provides large cutaneous and myogenous components for reconstruction of head and neck defects. A high incidence of radiologic atelectasis is evident postoperatively in these patients. The radiologic severity correlates with the size of the skin paddle used. The outcome is not related to the radiologic appearance. Pulmonary complications in this group are similar to those in patients undergoing other reconstructive modalities.

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Article Information

Accepted for publication August 16, 2001.

This study was presented at the annual meeting of the American Head and Neck Society, Palm Desert, Calif, May 16, 2001.

Corresponding author: Mark K. Wax, MD, Department of Otolaryngology/Head and Neck Surgery, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Mail Code PV-01, Portland, OR 97201 (e-mail: waxm@ohsu.edu).

References
1.
Seikaly  HKuzon Jr  WMGullane  PFHerman  SJ Pulmonary atelectasis after reconstruction with pectoralis major flaps. Arch Otolaryngol Head Neck Surg.1990;116:575-577.
2.
Schuller  DEDaniels  RLKing  MHouser  S Analysis of frequency of pulmonary atelectasis in patients undergoing pectoralis major musculocutaneous flap reconstruction. Head Neck.1994;16:25-29.
3.
Wax  MKHurst  J Pulmonary atelectasis after reconstruction with a latissimus dorsi myocutaneous flap. Laryngoscope.1996;106:268-272.
4.
Rigg  JRA Pulmonary atelectasis after anesthesia: pathophysiology and management. Can Anaesth Soc J.1981;28:305-313.
5.
Rao  MKReilley  TESchuller  DEYoung  DC Analysis of risk factors for postoperative pulmonary complications in head and neck surgery. Laryngoscope.1992;102:45-57.
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