Relative blood loss and operative time can predict length of stay following orthognathic surgery

Abstract

The aim of this study was to investigate the length of stay (LOS) following orthognathic surgery and thereby to establish a benchmark. The secondary aim was to identify predictors of postoperative LOS following orthognathic surgery. Patients were treated consecutively during the period 2010 to 2012. Inclusion criteria were (1) patient age ≥18 years, and (2) surgery involving a three-piece Le Fort I osteotomy, or a bilateral sagittal split osteotomy (BSSO), or bimaxillary surgery. A total of 335 patients were included. The following data were recorded: height, weight, body mass index (BMI), age, sex, operative time, intraoperative blood loss, and type of surgery. LOS was defined as the duration of time from date of surgery to date of discharge. The average LOS was 1.3 days following Le Fort I osteotomy, 1.3 days following BSSO, and 1.8 days following bimaxillary surgery. In the multivariate regression model ( R 2 = 0.11), predictors of a prolonged LOS were operative time ( P < 0.001) and relative blood loss ( P = 0.002). No significant effect of age, BMI, sex, or treatment on LOS was observed. The short duration of LOS found in this study supports the possibility of increasing outpatient pathways for selected patients.

Orthognathic surgery is considered a well-described and safe treatment with few complications, due to intensive scientific focus on surgical techniques and postoperative stability. Orthognathic surgery is often performed in young and healthy patients and has a predictable postoperative course and outcome. The reported length of stay (LOS) following orthognathic surgery ranges from 1.5 days to 8 days. A number of studies have identified predictors of a prolonged LOS following orthognathic surgery, including increased operative time, prolonged anaesthesia, increased surgical complexity, fixation type, and age. However, there are inconsistencies in the reported predictors of LOS and there is considerable variation in LOS following otherwise standardized and well-described procedures in orthognathic surgery, underlining the importance of further research in this field.

A primary concern of prolonged LOS is an increased risk of serious medical complications, e.g. deep vein thrombosis, nosocomial infections, and delayed healing. A rapid postoperative recovery following orthognathic surgery may increase overall patient satisfaction and benefit the planning and discharge of patients, thus improving the cost-effectiveness of the total treatment pathway. A thorough understanding of the predictors of LOS may facilitate the selection of an increased number of patients for outpatient treatment.

The biological hypothesis of the present study assumed significant predictive values of patient-specific and treatment-specific factors. The aims of this study were (1) to investigate the LOS following orthognathic surgery and establish a benchmark based on a large population treated at a Danish university hospital, and (2) to identify predictors of postoperative LOS following orthognathic surgery in a multivariate statistical model.

Materials and methods

Patients were treated consecutively during the period from 1 January 2010 to 31 December 2012 at a university hospital with a high volume of orthognathic surgical procedures. Inclusion criteria were (1) patient age ≥18 years, and (2) a surgical procedure involving a three-piece Le Fort I osteotomy, or a bilateral sagittal split osteotomy (BSSO), or a combination of the two in a bimaxillary procedure. Patients undergoing additional surgical procedures were excluded, as were patients treated in an outpatient setting. A total of 335 patients, 197 females and 138 males (female to male ratio of 1.4:1), with a mean age of 26.6 ± 2.5 years, were included.

Preoperative procedures

A functional jaw discrepancy was the main indication for orthognathic surgery. On the day before surgery, a full preoperative evaluation was performed by an anaesthesiologist, with emphasis on general health (American Society of Anesthesiologists (ASA) classification). Two hours before surgery, the patients received 3500 IU of low-molecular-weight heparin, tinzaparin, as a prophylactic anticoagulant (Innohep; Leo Pharma, Denmark) and 1 g of paracetamol (Pamol; Takeda Pharma, Denmark).

Surgical procedures

Hypotensive intravenous general anaesthesia was administered by a combination of remifentanil (GlaxoSmithKline Pharma, UK) and propofol (AstraZeneca, Sweden), supplemented with the inhalation of sevoflurane (Baxter, USA) on indication. After the induction of anaesthesia, local anaesthetic lidocaine–adrenaline 1% (AstraZeneca, Sweden) was administered in the surgical field. Patients received 40 mg methylprednisolone sodium succinate (Solu-Medrol; Pfizer, USA), 1000 mg metronidazole (Actavis, USA), and 1500 mg cefuroxime (Actavis, USA) intravenously. An additional dose of cefuroxime (1500 mg) was administered routinely in the case of surgery exceeding 3 h. Patients allergic to penicillin were given 600 mg clindamycin (Stragen Pharma, France).

A modified Obwegeser BSSO was performed in the mandible. In the maxilla, a standardized three-piece Le Fort I osteotomy was performed according to the procedure of Bell et al. The major palatine arteries were routinely preserved. In the case of haemorrhage, identifiable vessel ligation or cauterization was undertaken. Surgery was performed by senior staff. The operative time was recorded routinely from the start of surgery to the end of the procedure. Intraoperative blood loss was estimated by subtracting saline used for rinsing from the total volume collected in the suction device.

Postoperative procedures

Patients were transferred to the recovery unit. After recovery, general care was provided by specially trained nurses on the oral and maxillofacial surgery ward. Patients were discharged from the ward in accordance with standardized criteria, which included the patient being fully conscious, with normalized body functions, able to consume soft foods, well-informed about postoperative precautions and instructions, and with pain adequately managed.

Formulae used

The patient-specific estimated blood volume (EBV) was calculated as follows: EBV (ml) = weight (kg) × average blood volume (ml/kg). Reference values for average blood volume were 75 ml/kg for men and 65 ml/kg for women.

Patient-specific relative blood loss (RBL %) was calculated as follows: RBL (%) = (intraoperative blood loss (ml)/estimated blood volume (ml)) × 100.

Data management

Data were retrieved from the individual patient records; in the case of missing data, the patient was excluded from the study. The following factors were recorded: height, weight, body mass index (BMI), ASA classification, age, sex, operative time, intraoperative blood loss, and type of surgery. The dependent variable was the LOS, defined as the duration from the date of surgery to the date of discharge. Statistical analyses were conducted using IBM SPSS Statistics version 22 software (IBM Corp., Armonk, NY, USA). Descriptive statistics are presented as the mean and standard deviation (SD). The data were not normally distributed and a logistic transformation was performed. A multivariate stepwise regression analysis was performed to assess predictors of LOS. A P -value of <0.05 was considered statistically significant. The study was conducted in accordance with the Declaration of Helsinki.

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Dec 15, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Relative blood loss and operative time can predict length of stay following orthognathic surgery
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