Chymotrypsin with sialendoscopy-assisted surgery for the treatment of chronic obstructive parotitis

Abstract

Chronic obstructive parotitis (COP) is a common disease of the parotid gland. A total of 104 patients with COP were identified and randomized into a treatment group (52 cases) and a control group (52 cases). All patients underwent sialography and salivary gland scintigraphy (SGS) examinations before surgery. The patients in the treatment group received chymotrypsin combined with gentamicin via interventional sialendoscopy to irrigate the duct, and the control group received gentamicin alone. All patients were asked to record their pain on a visual analogue scale (VAS) before treatment and at 1 week, 2 weeks, 1 month, 3 months, and 6 months after surgery. The VAS score for pain intensity was decreased at 1 week post-treatment in both groups ( P < 0.05). Compared to the control group, the VAS score was lower in the treatment group at 1 week, 2 weeks, and 1 month post-treatment ( P < 0.05). The 6-month postoperative SGS results showed improved uptake and excretion in both groups ( P < 0.05). The treatment group exhibited higher scores for postoperative SGS excretion than the control group ( P < 0.05). The administration of chymotrypsin combined with gentamicin by sialendoscopy is effective for the treatment of non-stone-related COP and specifically improves the excretion function of the parotid gland.

Chronic obstructive parotitis (COP) is a common non-neoplastic disease that is characterized by recurrent parotid swelling and pain and may be aggravated while eating in some patients . This disorder generally results from local factors, such as sialolithiasis, stricture, kinks, mucus plugs, polyps, and foreign bodies. The common diagnostic approach for COP consists of ultrasound, computed tomography, sialography, and salivary gland scintigraphy (SGS) examinations ; however, these methods do not allow the direct visualization of the inner duct system to determine the cause of the ductal obstruction.

Among the endoscopic techniques that have been used widely in the diagnosis and treatment of various diseases, sialendoscopy has become a gold standard for the diagnosis of chronic obstructive sialadenitis . Sialendoscopy can provide direct visualization of the ductal system of the parotid glands, allowing the identification of factors causing an obstruction, as well as the irrigation of the duct with drugs, and can simultaneously facilitate the removal of stones. Many drugs can be used for irrigation, such as methyl violet, hyaluronidase, iodized oil, chloramphenicol, gentamicin, and dexamethasone. Chymotrypsin is a proteolytic enzyme extracted from the bovine or porcine pancreas that can decompose peptide chains and solubilize proteins, thereby promoting the dissolution and decomposition of purulent secretions and necrotic tissues. The use of chymotrypsin for clinical applications has been affirmed in the fields of ophthalmology and dermatology . The aim of this study was to evaluate the clinical effects of chymotrypsin combined with gentamicin administered via sialendoscopy for the treatment of COP.

Materials and methods

Approval for this study was obtained from the institutional review board of the China Medical University. All participants signed an informed consent agreement. All of the guidelines and protocols of the Declaration of Helsinki were followed during the course of the study.

Study design

A total of 104 patients (168 glands) with COP who attended the Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University (Shenyang, China) between June 2014 and December 2015, were selected for inclusion in this study. Patients were diagnosed with COP based on history, clinical manifestations, and a series of diagnostic methods including ultrasound, SGS examination, sialography, and sialendoscopy. Patients with diseases such as tumours and sialolithiasis diagnosed based on ultrasound findings were excluded. After SGS examination and sialography, patients diagnosed with chronic recurrent parotitis or Sjögren’s syndrome were also excluded. Furthermore, patients found to have negative stones, polyps, and foreign bodies under sialendoscopy were excluded.

After obtaining written informed consent, 104 patients meeting the necessary criteria were assigned randomly to two groups using a random number sealed-envelope system: 52 patients to the treatment group and 52 patients to the control group. Both the surgeon and the patient were blinded to the study group assignment.

Operative procedure

All patients underwent preoperative sialography and SGS examinations to exclude surgical contraindications and patients who were allergic to chymotrypsin. During surgery, a set of specialized probes (size 00 to 3) was used to dilate the natural opening of the parotid. Sialendoscopy (PolyDiagnost GmbH, Hallbergmoos, Germany) was then performed ( Fig. 1 ). The probe was 1.1 mm in diameter and had a working channel of 0.55 mm in diameter.

Fig. 1
Sialendoscopy was performed through Stensen’s duct.

In the treatment group, 5 mg of chymotrypsin and 80,000 units of gentamicin were mixed with 25 ml of sterile saline solution and injected into the duct through the irrigation channel of the endoscope until most of the fibre-like substances had disappeared from the field of view ( Fig. 2 a, b). The liquid mixture was retained in the parotid gland for approximately 3 to 5 min after removal of the endoscope. Pressure was then applied to the parotid region until clear liquid flowed out of the parotid duct. The control group patients received 80,000 units of gentamicin mixed with 25 ml of sterile saline solution to irrigate the duct. All patients in this study were asked to record their pain level on a visual analogue scale (VAS) before the operation and at 1 week, 2 weeks, 1 month, 3 months, and 6 months after the operation.

Fig. 2
(a) Mucus plugs and fibre-like substances were observed via sialendoscopy. (b) A mixture was injected into the ducts through the irrigation channel of the endoscope until most of the fibre-like substances had disappeared from the field of view.

Evaluation of the results

The VAS score was used to evaluate clinical symptoms including pain and swelling of the parotid gland before and after treatment. The VAS consisted of a 0–10 cm scale that was used to express the degree of clinical symptoms as manifested by a combination of pain and swelling, with 0 representing no clinical symptoms and 10 representing unbearable clinical symptoms.

SGS examinations were used for the quantitative evaluation of uptake and excretion in the salivary glands before and 6 months after the operation. The patient was injected intravenously with approximately 370 MBq (10 mCi) of 99m Tc-pertechnetate and salivary gland scintigraphy was performed for 30 min with single photon emission computed tomography (SPECT). Vitamin C (0.2 g) was administered orally at 20 min to stimulate salivary gland excretion. The mean functional parameters of the bilateral parotid and the submandibular glands were calculated according to the radioactive count and the corresponding time for the evaluation of salivary gland function.

Data analysis

IBM SPSS Statistics version 19.0 software (IBM Corp., Armonk, NY, USA) was used for the data analysis. Comparisons of the VAS scores and SGS results of each group before and after surgery were performed using a paired t -test. The difference in the treatment effect between the two patient groups was compared using an independent samples t -test. A P -value of less than 0.05 was considered statistically significant.

Results

The patients in the treatment group (18 male and 34 female) ranged in age from 29 to 72 years, with a mean age of 47.1 years. The disease duration ranged from 3 to 48 months (mean 8.4 months). The patients in the control group (19 male and 33 female) ranged in age from 25 to 70 years, with a mean age of 48.2 years. The disease duration ranged from 2 to 50 months (mean 8.8 months). The differences between the two groups with regard to sex, age, and average disease duration were not statistically significant ( P > 0.05) ( Table 1 ).

Table 1
Basic patient characteristics.
Treatment group
( n = 52)
Control group
( n = 52)
Sex, n
Male 18 a 19
Female 34 a 33
Age (years), mean ± SD 47.10 ± 8.56 a 48.21 ± 9.12
Disease duration (months), mean ± SD 8.4 ± 7.3 a 8.8 ± 7.4
SD, standard deviation.

a P > 0.05, compared to the control group.

Varying degrees of stenosis and expansion of the main parotid duct and branches were found via preoperative sialography in the patients in this study; some exhibited typical sausage-like images ( Fig. 3 ). SGS examinations showed normal or slightly decreased uptake and considerably decreased excretion ( Fig. 4 a). Hyperemia of the ductal wall ( Fig. 5 ), mucus plugs, and fibre-like substances ( Fig. 6 ) were also detected via sialendoscopy.

Fig. 3
Varying degrees of stenosis and expansion of the main parotid duct and branches were observed via preoperative sialography; some cases exhibited typical sausage-like images.

Fig. 4
(a) Salivary gland scintigraphy showed normal or slightly decreased uptake and considerably decreased excretion. (b) The postoperative uptake ratio (UR15) and excretion fraction after 6 months were significantly higher than the preoperative uptake ratio and excretion fraction.

Fig. 5
Hyperemia of the ductal wall.

Fig. 6
Fibre-like substances.

No significant differences were observed in the preoperative VAS scores between the two groups ( P > 0.05). The 1-week postoperative VAS scores were significantly lower than the preoperative VAS scores in both groups ( P < 0.05). The postoperative VAS scores in the treatment group at 1 week, 2 weeks, and 1 month after the procedure were significantly lower than those in the control group ( P < 0.05). However, no significant difference was found in the postoperative VAS scores between the two groups after 3 months or 6 months ( P > 0.05) ( Table 2 ).

Table 2
VAS scores of the two groups of patients before and after surgery.
Observation time point Treatment group
( n = 52), mean ± SD
Control group
( n = 52), mean ± SD
Before treatment 6.12 ± 0.96 6.08 ± 1.02
After treatment
1 week 2.63 ± 1.07 a,b 3.13 ± 1.28 a
2 weeks 1.63 ± 0.84 b 2.35 ± 0.86
1 month 1.10 ± 0.85 b 1.62 ± 0.97
3 months 0.77 ± 0.76 1.08 ± 0.93
6 months 1.23 ± 1.17 1.54 ± 1.45
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Dec 14, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Chymotrypsin with sialendoscopy-assisted surgery for the treatment of chronic obstructive parotitis
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