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Year : 2021  |  Volume : 23  |  Issue : 1  |  Page : 6-10

Mastoid cavity obliteration with hydroxyapatite granules: A prospective study

1 Department of Otorhinolaryngology, Pt. BD Sharma Postgraduate Institute of Medical Sciences, Rohtak, Haryana, India
2 Department of Otolaryngology Head and Neck Surgery, AIIMS, Bhatinda, Punjab, India

Date of Submission29-May-2020
Date of Decision27-Jun-2020
Date of Acceptance31-Aug-2020
Date of Web Publication06-May-2021

Correspondence Address:
Dr. Jitu Sam George
Department of Otorhinolaryngology, Pt. BD Sharma Postgraduate Institute of Medical Sciences, Rohtak, Haryana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/SJOH.SJOH_22_20

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Background: Modified radical mastoidectomy is the mainstay in the treatment of a case of unsafe CSOM. In order to reduce the side effects of an open matoid cavity, many methods to obliterate the cavity have been devised. Aims & Objectives: Cavity obliteration was done to study the efficacy of mastoid cavity obliteration Material and Methods: We carried out cavity obliteration with hydroxyapatite in 20 patients and compared the results with non obliteration. Results: We observed that in addition to reduction in size of cavity, there is better epithelisation and hence faster healing of the mastoid cavity. There is also a significant improvement in hearing status of the patients. Conclusion: Modified Radical Mastoidectomy followed by cavity obliteration with hydroxyapatite granules has numerous advantages compared to leaving the cavity as such.

Keywords: Cavity obliteration, hydroxyapatite, mastoidectomy

How to cite this article:
George JS, Kakkar V, Gupta V, Dheeraj S, Bhukar S, Swati, Verma M. Mastoid cavity obliteration with hydroxyapatite granules: A prospective study. Saudi J Otorhinolaryngol Head Neck Surg 2021;23:6-10

How to cite this URL:
George JS, Kakkar V, Gupta V, Dheeraj S, Bhukar S, Swati, Verma M. Mastoid cavity obliteration with hydroxyapatite granules: A prospective study. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2021 [cited 2022 Nov 29];23:6-10. Available from: https://www.sjohns.org/text.asp?2021/23/1/6/315572

  Introduction Top

Chronic otitis media is one of the most common infections of the ear. It is a global problem and continues to affect a large number of patients, particularly in developing countries. Chronic suppurative otitis media (CSOM) is of two types, namely safe and unsafe, based on its clinical characteristics. While the treatment of safe type is fairly standardized, unsafe has many treatment options. However, usually, surgery is the treatment of choice, i.e., modified radical mastoidectomy.

Various mastoid procedures used for addressing chronic ear infection are simple mastoidectomy, canal wall up mastoidectomy, canal wall down mastoidectomy, radical mastoidectomy, modified radical mastoidectomy, and mastoid obliteration.[1]

Even though canal wall up mastoidectomy has certain advantages like preservation of the posterior canal wall, elimination of recurrent infections, no need for periodic cleaning, and simplification of ossicular reconstruction, relapse rates of cholesteatoma as high as 36% in adults and 67% in children makes it less popular. The advantages of canal wall down mastoidectomy include excellent exposure of the entire attic and middle ear and complete eradication of the disease. Using this technique, the relapse rate could be as low as 2%. Its main disadvantages are the accumulation of debris in the exteriorized mastoid cavity, which requires periodic cleaning, water restrictions to prevent infection, chronic discharge from the cavity, dependence on a surgeon for regular cleaning of the cavity, nonesthetic meatoplasty, reports of vertigo in cold weather and during swimming, difficulty with fitting a hearing aid and problems relating to ossicular reconstruction.[2]

To tackle these situations and to improve the long term stability of the mastoid cavity, the concept of mastoid cavity obliteration was introduced. Further, various studies have even reported an improvement in hearing following mastoid cavity obliteration.[3]

The concept of mastoid obliteration was first introduced in 1911 by Mosher to promote the healing of a mastoidectomy defect.[4] Since then, numerous reports detailing a variety of techniques of obliterating the mastoid cavity have evolved, which has revolutionized the field of mastoid surgeries.

Techniques of mastoid obliteration

Local flaps[5],[6]

  1. Meatally based mucoperiosteal flap (Palva flap)
  2. Inferiorly based periosteal-pericranial flap
  3. Temporalis muscle flap
  4. Temperoparietal fascial flap.

Free grafts[5],[6]

  1. Bone chips/bone pate
  2. Cartilage
  3. Fat
  4. Fascia
  5. Hydroxyapatite.

Synthetic calcium hydroxyapatite with chemical formula, [CaO (PO4) (OH) is one of the most important bone substitutes available today as its synthetic equivalent has biocompatibility and osteoconduction. Bone conduction happens when a porous structure is implanted on the bone or near it. Fibro-vascular tissues, capillaries, and bone-forming cells migrate to the porous structure and start forming new bone. The success of such mineral grafts is based on their resorption by osteoclasts, which contribute to forming new bone. The nondecalcified bone graft is gradually and slowly absorbed by osteoclasts, which open gaps in the calcified bone, enabling vascular growth and the inflow of inflammatory cells, which explains how this tissue can maintain its mechanical force. Moreover, the collagen present in these bone substitutes make up the substrate for the mineralization and promotes osteoinduction.[7]

Major attempts to synthetically fabricate hydroxyapatite, which is the major mineral component of bone, began in the late 1970s and early 1980s.[8]

Advantages of hydroxyapatite ceramic as an implant for bony reconstruction in the middle ear are its biological inertness, easy availability, controlled resorption, and remodeling because of standard manufacturing procedures and less possibility of transmission of disease.[9]

Mastoid cavity obliteration, with the help of hydroxyapatite, has been the subject of many studies. All these studies proved that using hydroxyapatite granules for mastoid cavity obliteration significantly reduces the postoperative complications in a modified radical mastoidectomy patient. The present study was undertaken to evaluate the same in Indian patients.

  Materials and Methods Top

Forty patients of either sex <60 years of age who had evidence of the active squamosal type of disease without any complication were enrolled in the study.

Patients were randomly allotted into two groups by drawing of lots:

  • Group 1: Case group of twenty patients, in which the postoperatively mastoid cavity was obliterated with hydroxyapatite granules
  • Group 2: Control group of twenty patients in which postoperatively mastoid cavity was left unobliterated.

Exclusion criteria

Patients having age >60 years, patients with intracranial or infratemporal complications and those with any congenital anomalies of ear and external auditory canal or with any source of infection in the nose and throat were excluded from the study.

Modified radical mastoidectomy was performed for all the patients under general anesthesia. In Group 1 patients, the cavity was obliterated by hydroxyapatite granules obtained by crushing commercially available hydroxyapatite blocks (0.5–1 cm), which were dipped in antibiotic solution (Co-amoxyclav) for 10 min, and the obliterated cavity was covered with an inferiorly based periosteal flap. The epitympanum was also obliterated. Whereas in Group 2, the cavity was left unobliterated.

Postoperatively, all patients were put on tablet amoxiclav 625 mg TDS, tablet diclofenac 50 mg BD and tablet levocetrizine 5 mg OD for 10 days. The sutures were removed on the 10th postoperative day. The patients were followed up on out-patient department basis on the 15th, 30th, 45th, and 90th days postoperatively. The parameters studied during the follow-up period were the presence or absence of pain, discharge, debris, granule extrusion, re-epithelization, and complications if any. Postoperatively, audiometry was done after 6 weeks and 12 weeks and the results were compared with the preoperative audiograms.

  Results Top

It was observed that the majority of the patients were in the age group of 11–20 years, 7 in Group 1, and 9 in Group 2. The mean age of Group 1 was 24.45 years with median 22 years and the mean age of Group 2 was 26.1 years with median 21.5 years. There were 24 male patients (12 in each group), while there were 16 female patients (8 in each group).

Most of the patients acquired the disease in childhood. The mean duration of discharge in Group 1 was 12.55 years (median 8 years) and the mean duration in Group 2 was 11 years (median 8.5 years). All the patients complained of mucopurulent, foul-smelling discharge, which was scanty in nature. Twelve (60%) patients in Group 1 complained of blood-stained discharge at some point during the course of disease, while only 9 (45%) Group 2 patients complained of the same. Sixteen (80%) patients of Group 1 had difficulty in hearing, whereas only 15 (75%) patients of Group 2 complained hearing difficulty. No patients had any history of associated complications.

On otoscopic examination of patients in Group 1, 5 (25%) had granulations while 13 (65%) had the evidence of frank cholesteatoma. There were 2 (10%) cases of polyps filling the entire external auditory canal. In Group 2, 4 (20%) had granulations and 13 (65%) patients had frank cholesteatoma. However, there were 3 (15%) patients with polypoidal tissue covering the tympanic membrane.

All the patients in both Group 1 and Group 2, even those who did not specifically give a history of hearing loss, had conductive deafness on audiometric evaluation. A–B gap of more than 30 dB was present in 13 (65%) patients of Group 1 and 14 (70%) patients of Group 2, understandably pointing toward significant to severe hearing loss. The mean A–B gap in Group 1 was 35.2 dB 8.33 dB and in Group 2 was 37.55 dB ± 8.4 dB.

Two patients in Group 1 had partial granule extrusion associated with discharge, which persisted even on the 90th postoperative day. Eighteen patients in Group 1 and twelve patients in Group 2 had well epithelized cavities on the 90th postoperative day [Table 1]. The difference between the two groups was found to be statistically significant (P = 0.03). No patients in either group complained of significant pain and also none had any complications.
Table 1: Findings on day 90

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On applying Chi-square test, P = 0.63 for discharge (insignificant) and 0.03 for epithelisation (significant).

All the patients in both Group 1 and Group 2, even those who did not specifically gave a history of hearing loss had conductive hearing loss on audiometric evaluation. A–B gap of >30 dB was present in 13 (65%) patients of Group 1 and 14 (70%) patients of Group 2, understandably pointing toward significant to severe hearing loss [Figure 1] and [Table 2]. Average A–B gap in Group 1 was 35.2 dB with a standard deviation of 8.33 dB and in Group 2 was 37.55 dB with a standard deviation of 8.4 dB.
Figure 1: Preoperative pure tone audiogram findings

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Table 2: Preoperative pure tone audiogram findings

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Fourteen cases (70%) in Group 1 and 12 cases (60%) in Group 2 reported better hearing in the operated ear on audiometry on the 90th postoperative day. The mean gain in the hearing was 6.75 dB in Group 1 and 3.45 dB in Group 2 [Figure 2] and [Table 3]. The difference between the two groups was found to be statistically significant (P = 0.046).
Figure 2: Hearing improvement on day 9

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Table 3: Hearing improvement on day 90

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  Discussion Top

This prospective study was conducted in the Department of Otorhinolaryngology, Pt. B. D. Sharma, PGIMS, Rohtak in forty patients of either sex < 60 years of age having the active squamosal type of suppurative otitis media. Eighteen (90%) patients of the Group 1 cases in our study showed epithelization on the 45th postoperative day, and all of them had well epithelized cavity on the 90th postoperative day. Only 11 (55%) patients showed epithelization of the cavity on the 45th postoperative day in Group 2. On the 90th postoperative day in Group 2, 12 (60%) patients had well epithelized cavity and 3 (15%) patients had partially epithelized cavity. Studies by Chappola and Mutta,[9] Yung,[10] and Munjal et al.[11] also reported similar results. According to Yung, only two patients had granulation tissue developing in the cavity preventing epithelization.[10] Whereas 60% and 88% had epithelization on the 90th postoperative day in the studies conducted by Chappola and Mutta[9] and Munjal et al.,[11] respectively. Previous studies using muscle flaps and cartilages have reported a complete epithelization rate of around 80% after 90 days, due to a reduction in the size of the cavity and due to the availability of a vascularized base over which the regenerating epithelium grows faster and survives better.[12] In the present study using hydroxyapatite granules, the results are even better because of the resistant property and porous nature of the material, which results in excellent bio-compatibility with the host bone and thus gives a bio-active lining platform on which the epithelium can regenerate. Similar results have been obtained using bone pate by Deshmukh et al.[12] and Moffat et al.[13] However, by using the drilled out bone pate from the diseased mastoid for obliteration, one cannot overlook the increased chances of disease recurrence, a complication that cannot occur with hydroxyapatite.

No patients had complete extrusion of granules in our study. There were two cases of minimal extrusion not associated with increased discharge or signs of acute infection. This probably could be due to the overzealous filling of the cavity. There was no evidence of any extrusion in 34 cases studied by Yung, in which the mastoid cavity was obliterated with hydroxyapatite.[10] Munjal et al. reported in their study that 5 out of the 25 obliterated cases had extrusion of granules on the 15th day and out of this, only 1 case had extrusion on the 90th day.[11] Thus though reported in the literature, extrusion of granules is not such a common and unmanageable complication.

In this study, only 2 (10%) patients complained of pain in the operated ear, which subsided after 2 days. No patient complained of earache in the second postoperative week. There were no complaints of dizziness, tinnitus, or vertigo in any of the operated cases. None of the patients had perichondritis or meatal stenosis in the postoperative period. In their study, Chappola and Mutta also reported that out of 20 cases, in which the cavity was obliterated, only one case developed continuous ear discharge with perichondritis and subsequently canal stenosis for which canaloplasty was done after 6 months.[9] Park et al. found that only 1 out of the 18 cases, in which the cavity was obliterated by hydroxyapatite developed mastoid complications and with no statistically significant difference with other materials used for obliteration.[14] This quite clearly proves that the obliteration of mastoid cavities with hydroxyapatite does not per se result in the development of complications, which will hamper the results of the surgery. Instead, it gives many advantages such as reduced wax formation, less dependence on the doctor for cleaning of the cavity, and other cavity-related problems.

One of the significant achievements, though small, was the improvement in the hearing status. The fact that modified radical mastoidectomy usually involves removal of the incus and the head of the malleus to clear the disease ends up with at least Type 3 tympanoplasty, thereby resulting in hearing loss up to 30 dB. However, in our study, though 6 (30%) of the cases in Group 1 did not show any conductive gain or even showed a widening of the air-bone gap, there was mean gain in hearing of 6.75 dB overall. Munjal et al. also have reported an AB gap gain of 2.04 dB.[11] Previous studies using muscle flaps and bone pate have not mentioned much improvement in hearing, and this can be attributed to the fact that the conductiveness of hydroxyapatite, which form the posterior bony canal, does help in better acoustic conduction resulting in better hearing.

There is no doubt regarding the fact that the patient has to spend more money for commercially available blocks of hydroxyapatite, i.e., 1 g of porous hydroxyapatite (10 cc) costs about Rs. 1800 in the retail market. Whereas in other cases, material required for obliteration is freely available in the form of free graft or pedicled flap from the patient's body itself. However, the benefits far outweigh the costs in terms of decreased morbidity, better AB gain, and patient satisfaction with hydroxyapatite.

Furthermore, there is no element of donor site morbidity or disease recurrence in the cases done. Hence, it can be inferred from the present study that cavity obliteration with hydroxyapatite granules is a useful tool in reducing postoperative morbidity of the patients, including the cavity problems.

  Conclusion Top

Modified radical mastoidectomy is the treatment of choice for active squamosal type of CSOM. However, there are numerous disadvantages of the resulting open cavity. Cavity obliteration with hydroxyapatite granules is better as there is no element of donor site morbidity, no disease recurrence, increased rate of re-epithelization, and improvement in hearing status.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Lambert RP. Mastoidectomy. In: Flint PW, Haughey BH, Lund VJ, Niparko JK, Richardson MA, Robbins KT, et al., editors. Cummings Otolaryngology Head and Neck Surgery. 5th ed.. China: Elsevier; 2010. p. 2009-16.  Back to cited text no. 1
Ghiasi S. Mastoid cavity obliteration with combined palva flapand bone pâté. Iran J Otorhinolaryngol 2015;27:23-8.  Back to cited text no. 2
Ezzat AE, El-Begermy MM, Mahmoud AM, Eid MI. Comparison of natural and synthetic materials to improve hearing after obliteration of the mastoid cavity. J Hear Sci 2015;4:OA36-41.  Back to cited text no. 3
Mosher HP. A method of filling the excavated mastoid with a flap from the back of the auricle. Laryngoscope 1911;21:1158-63.  Back to cited text no. 4
Mehta RP, Harris JP. Mastoid obliteration. Otolaryngol Clin North Am 2006;39:1129-42.  Back to cited text no. 5
Kurien G, Greeff K, Gomaa N, Ho A. Mastoidectomy and mastoid obliteration with autologous bone graft: A quality of life study. J Otolaryngol Head Neck Surg 2013;42:49.  Back to cited text no. 6
Hamerschmidt R, Santos RF, Araújo JC, Stahlke HJ Jr., Agulham MA, Moreira AT, et al. Hydroxyapatite granules used in the obliteration of mastoid cavities in rats. Braz J Otorhinolaryngol 2011;77:315-21.  Back to cited text no. 7
Friedman CD, Costantino PD, Takagi S, Chow LC. Bone source hydroxyapatite cement: A novel biomaterial for craniofacial skeletal tissue engineering and reconstruction. J Biomed Mater Res 1988;43:428-32.  Back to cited text no. 8
Chappola S, Mutta I. Mastoid obliteration vs Open cavity: A comparative study. Indian J Otolaryngol Head Neck Surg 2014;66:2007-13.  Back to cited text no. 9
Yung MW. The use of hydroxyapatite granules in mastoid obliteration. Clin Otolaryngol Allied Sci 1996;21:480-4.  Back to cited text no. 10
Munjal M, Passey J, Agarwal A, Meher R. Hydroxyapatite granules for mastoid cavity obliteration: A study of 25 cases. Internet J Otorhinolaryngol 2004;3:2.  Back to cited text no. 11
Deshmukh S, Sharma A, Dabholkar J. Mastoid cavity obliteration: Our experience. Otolaryngol Pol 2012;66:379-81.  Back to cited text no. 12
Moffat DA, Gray RF, Irving RM. Mastoid obliteration using bone pâté. Clin Otolaryngol Allied Sci 1994;19:149-57.  Back to cited text no. 13
Park JS, Kang MY, Hong JC, Park BG, Kang MK. Result of mastoid obliteration according to the graft materials: Autogenous bone, allogenic bone, hydroxylapatite. Int Adv Otol 2011;7:305-10.  Back to cited text no. 14


  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3]

This article has been cited by
1 Mastoid obliteration with hydroxyapatite vs. bone pâté in mastoidectomy surgery performed on patients with cholesteatoma and chronic suppurative otitis media: a retrospective analysis
Jantine J. Lindeboom, P. M. W. van Kempen, J. Buwalda, B. O. Westerlaken, D. A. van Zuijlen, S. J. H. Bom, F. B. van der Beek
European Archives of Oto-Rhino-Laryngology. 2022;
[Pubmed] | [DOI]


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