Drains after Thyroidectomy for Benign Thyroid Disorders; Are Associated With More Pain, Wound Infection and Prolonged Hospital Stay
Muthaa T, Kaisha W, Githaiga J
School of Medicine, University of Nairobi
Prophylactic drainage after thyroidectomy has been a regular practice at Kenyatta National Hospital( KNH). This has been used for the potential to avert post-operative fluid accumulation (hematoma or seroma) and also for detection of continuing bleeding. This is aimed at preventing or delaying airway compression that has potential for serious morbidity and mortality. However their importance in these situations has been questioned in recent literature.
To evaluate the difference in outcomes in drained versus non-drained groups after thyroidectomy for benign thyroid disorders.
Prospective randomized clinical study consisting of 90 patients who were admitted for total thyroidectomy and were randomized into two groups of 45 participants.
The general surgical wards and theatres at Kenyatta National Hospital.
Ninety consecutive patients with benign thyroid disorders scheduled for total thyroidectomy or lobectomy, who met the inclusion criteria were recruited over a study period of 9 months from January to September 2011. They were randomly assigned to one group in whom closed drains were used and another in whom no drains were used after thyroidectomy. They were then evaluated postoperatively for hematoma and seroma formation, pain assessed by the visual analogue scale (VAS), duration of hospital stay and necessity for re-operation.
The mean VAS score was significantly lower in the non-drained group patients at 6, 12 and 24 hours postoperatively (p= 0.001). Four cases of hematoma (8.9%) occurred in the drained group, whereas none of patients in the non-drained group developed hematoma (p=0.04). None of the patients in the non-drain group had post-surgical wound infection whereas four (9%) of those who had drains developed wound sepsis. No participant required re-operation for any complication nor developed seroma and all complications were successfully managed conservatively.
Prophylactic drainage after thyroidectomy for benign goiters does not show any benefit in hematoma prevention and is associated with increased hospital stay and post-operative pain.
Prophylactic drains are still regularly used in many surgical units after thyroid surgery. Their use is based on practice rather than scientific evidence and reliant on the surgeon’s experiences and teaching (1). Conventionally, the major anticipation for prophylactic drains usage is to avert complications after surgery by draining off the postoperative hematoma or lymphatic fluid and to notify the surgeon concerning early postoperative hemorrhage (2).
Conversely, prophylactic drain usage might be discarded in non-complicated cases since drainage is minimal and might not be required, or since sufficient haemostasis can never be expendable by using drains; and where haemostasis is insufficient, seroma or hematoma would be the inevitable conclusion (3-5). Critical complications, for instance postoperative haemorrhage, compression of air passages or hematoma formation, can be averted in the majority of patients (6,7). In view of these improvements, the requisite of prophylactic drainage in thyroid surgery might be queried.
There is a controversy on the role of drains in thyroid surgery. Many studies have showed that prophylactic drainage is unnecessary after routine thyroid surgery (8, 9). However these studies were done in developed Western countries and it is doubtful if their results maybe generalizable to developing countries like Kenya. Moreover, the goiters in developing countries are much larger than those reported in the Western literature (10). The aim of this study was to evaluate the differences in outcome in drained versus non-drained participants after thyroidectomy for benign thyroid disorders.
Study population: all consenting adult patients scheduled to undergo lobectomy or total thyroidectomy, intended for benign thyroid disorders at Kenyatta National Hospital (KNH), a tertiary hospital in Nairobi, Kenya.
Study design: This was a prospective randomized clinical study with two 2 treatment arms: one with a drain and the other without a drain.
Sample size: was calculated to detect a 40% reduction in the VAS score between drained group and the non-drain group, with a α of 0.05 and a power of 80%. This gave a minimum of 44 patients in each arm of the study.
Exclusion criteria: Patients who had a previous thyroid operation as this may be associated with operative difficulty. Patients with Grave’s disease whose operative field is associated with excess oozing. Patients receiving anticoagulation treatment for various indications and patients who refused or were unable to give consent to participate in the study. Sampling method: All eligible patients were counseled and recruited into the study. They were then subjected to randomization based on gender, age, type of procedure and goiter size.
Method: Pre-study ethical approval was obtained from the ethics committee. The principal investigator and the research assistant who were trained clinicians recruited the patients. Consent for participation in the study was sought from the patients after counseling. Randomization was carried out using a computer-developed table of random numbers. This randomization was done by an autonomous information technology consultant based on gender, age, type of procedure and goiter size. The surgeon was made aware of the group designation just before the closure of the wound. Total thyroidectomy or total lobectomy was carried out for various indications, with the technique and method of wound closure being similar. All patients received three doses of prophylactic antibiotics within 24 hours; the first dose being given intra operatively. Closed suction drain French Gauge 10 was inserted before wound closure, for those in the drainage group. Intra-operative surgical wound status was observed and recorded at the beginning of the operation. Patients were reviewed at 6, 12, 24, 48, 72 and 96 hours. Hematoma and seroma development, postoperative pain, hospital stay, wound infection and necessity for re-operation, were noted. Visual analogue scale was used to assess postoperative pain (11). The patients were discharged when they were free of complication or when pain was well controlled on oral analgesics with drain removal when drainage volume was less than 30cc in 24 hours. The time when the decision to discharge was made was recorded.
Data analysis: Differences among the participants in the two groups were analyzed using student t-test and chi squared test. Results were expressed as mean± SD. 2 test was performed for the hematoma and seroma formation and histopathological diagnosis. Student t-test was done for the age, hospital stay, and VAS score.
A total of 90 adult patients over a nine month period divided into two groups of 45 participated in the study. The main surgical indications were symptomatic multinodular goiter (MNG) in 61(67.8%) patients, solitary nodular goiter 26(28.9%) and diffuse thyroid enlargement in 3(3.3%).
Gender, age, procedure, preoperative diagnosis and histopathological results
There was no significant difference in the gender, age, procedure, preoperative diagnosis, histopathological results and weight of the glands removed among the two groups (P=0.12, P=0.13, P=0.38, P=0.78, P=1.0 and P=0.47, respectively)(Table 1).
Click to view table 1
Mean VAS score for level of pain
The mean VAS score for level of pain was significantly lower in the non-drained group (3.6±1.5) compared to the drained group (7.0±2.2) patients at 6 hours postoperatively (P=0.001) and a similar result was demonstratedat12hoursand24hourspostoperatively when the non-drained group (2.3±0.9), (1.4±0.8) was compared with the drained group (5.9±1.8), (4.7±2.0) respectively (P=0.001).
There was a consistent reduction of mean level of pain with time post-operatively which was observed in both the drained and non-drained groups. However, the pain reduction was more marked and experienced for fewer hours in the non- drain group compared to the drain group. Figure1.
Click top view figure 1