# Cranial Sutures as a Cause of Osseointegration Failure in Bone-Anchored Implants: Case Reports

Michaël Risoud, Cyril Beck, Pierre-Emmanuel Lemesre, Christophe Vincent,

Philippine Toulemonde

► To cite this version:

Michaël Risoud, Cyril Beck, Pierre-Emmanuel Lemesre, Christophe Vincent, Philippine Toulemonde. Cranial Sutures as a Cause of Osseointegration Failure in Bone-Anchored Implants: Case Reports. B-ENT, 2025, B-ENT, 20, pp.210-212. 10.5152/B-ENT.2024.241596. hal-05280543

HAL Id: hal-05280543

https://lilloa.hal.science/hal-05280543v1

Submitted on 24 Sep 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

DOI: 10.5152/B-ENT.2024.241596

# Cranial Sutures as a Cause of Osseointegration Failure in Bone-Anchored Implants: Case Reports

Michaël Risoud ID, Cyril Beck ID, Pierre-Emmanuel Lemesre ID, Christophe Vincent ID, Philippine Toulemonde ID

Department of Otology and Neurotology, CHU (Centre Hospitalier Universitaire) de Lille: University Hospital of Lille - Henri Warembour Faculty of Medicine, Lille, France

**Cite this article as:** Risoud M, Beck C, Lemesre P, Vincent C, Toulemonde P. Cranial sutures as a cause of osseointegration failure in bone-anchored implants: case reports. B-ENT 2024;20(3):210-212.

## ABSTRACT

This report discusses 2 clinical cases where the failure of osseointegration in bone-anchored implants may be associated with their placement directly in cranial sutures. The increasing shift toward minimally invasive surgical techniques for implant placement, such as the minimally invasive Ponto surgery (MIPS) and the punch technique, raises concerns about the risk of inadvertently positioning implants on cranial sutures, which can lead to the failure of osseointegration. In the first case, the Ponto (Oticon) implant and abutment were placed using MIPS. Two months post-operation, minimal movement was observed until the implant was significantly displaced, necessitating its removal. A subsequent computed tomography (CT) scan revealed that the implant had been placed in the asterion. The second case involved a Bone Anchored Hearing Aid (BAHA-Cochlear) implant and abutment inserted via a punch and drill technique. Early mobilization of the abutment was observed, progressively worsening until the implant was removed 2 months post-operation. A CT scan showed that the implant was located at the parieto-occipital suture. These cases highlight a potential complication of minimally invasive implant surgery, suggesting that blind placement could elevate the risk of implant failure due to interference with cranial sutures. This underscores the importance of enhancing surgical precision and pre-operative planning with imaging.

**Keywords:** Bone-anchored implants, osseointegration, minimally invasive surgery, cranial sutures, case report

## Introduction

Bone conduction prostheses are frequently used in the management of conductive hearing loss and for the mono-pseudo-step rephonic rehabilitation of unilateral deafness.¹⁻³ These prostheses are typically mounted on an abutment fixed to a bone-anchored implant. The techniques for placing bone-anchored implants have evolved to become less invasive over the years, from incision and skin thinning to tissue-preserving incisions and eventually to no-incision methods.⁴⁻⁸ Nevertheless, failures in osseointegration, ranging from 0 to 18% with implant extrusion, still occur.²,⁹,¹⁰ Two cases are reported where control CT scans showed the implants had been placed on a cranial suture, potentially explaining the failures.

## Case Presentation

The first case involves a 47-year-old female with probable congenital right-sided deafness. A 1-month trial with a headband

demonstrated significant subjective benefits from bone conduction device rehabilitation. A Ponto implant (Oticon Medical, Smorum, Denmark) BHX 4 mm pre-mounted on a 12 mm abutment was placed under local anesthesia using the Minimally Invasive Ponto Surgery (MIPS) technique. There was no postoperative pain or infections. Given good healing, the external processor was mounted onto the abutment 1 month and 10 days post-surgery. The patient experienced sensations of abutment mobility and “bone noise” when turning her head. Two months postoperatively, the implant mobilized and had to be removed. A subsequent cranial CT scan showed that the implant had been placed in the asterion (Figure 1).

The second case involves a 41-year-old female with bilateral moderate conductive hearing loss, predominantly on the left side, due to bilateral acquired stenosis of the external auditory canals. A headband trial of bone conduction fitting was highly successful subjectively. A BAHA implant (Cochlear, Sydney, Australia) BA300 3 mm mounted on a 10 mm abutment

Corresponding author: Michaël Risoud, e-mail: michael.risoud@chu-lille.fr

Received: May 8, 2024 Revision Requested: July 8, 2024 Last Revision Received: July 14, 2024 Accepted: August 6, 2024.

Publication Date: September 6, 2024.

Available online at www.b-ent.be

<figure><img src="image_3.png" /></figure>

CC BY 4.0: Copyright@Author(s), "Content of this journal is licensed under a Creative Commons Attribution 4.0 International License."
<figure><img src="image_4.png" /><figcaption>**Figure 1.** Volumetric cranial CT scan (A) with magnification (B) on the area of interest (dotted rectangle) showing the implantation site (arrow) at the asterion, as well as its position relative to the soft tissues (C) with a distance of 55 mm from the external auditory canal.</figcaption></figure>

was placed under local anesthesia using a minimally invasive punch and drill technique. There was no postoperative pain or infections. However, slight pillar mobility was noted 1 month postoperatively. Fitting of the external processor was not permitted, and the condition worsened, leading to implant removal 2 months postoperatively. A subsequent cranial CT scan revealed that the implant had been placed on the parieto-occipital suture (Figure 2).

Informed consent was obtained from the 2 patients who agreed to participate for the purpose of case report writing.

## Discussion

First of all, it should be stressed that these 2 clinical cases do not allow for definitive conclusions or recommendations. They merely suggest some warnings.

These clinical cases suggest that minimally invasive surgery without visualization of the bone insertion area might increase the risk of accidental placement on a cranial suture, leading to osseointegration failure. This is also a consideration for techniques involving incisions, as dissection is performed above the periosteum layer, and if the periosteum is only removed over a diameter of 4 mm, it may obscure the suture from view. In practice, the periosteal stripping is often more extensive in the case of a technique with an incision (12-15 mm), which

facilitates the analysis of the drilling point and the avoidance of any potential suture.

The development of minimally invasive techniques for placing bone-anchored implants has advantages such as reducing the risk of bleeding, pain, infection, or healing complications and cosmetic sequelae, in addition to shortening the operative time.⁴,⁸ But, this comes at the expense of blind surgery concerning the precise implant placement on the cranial bone. Ideally, the implantation site should have good bone quality, with a thickness over 3 mm, and avoid not only diploic cranial vessels but also mastoid cells and cranial sutures.¹¹ Poor quality of the implantation site (irregular surface) is frequently reported in cases of implant loss.¹⁰ Cranial sutures are therefore areas to avoid for implantation. However, avoiding these becomes more challenging with minimally invasive surgery, especially in the absence of pre-operative planning (measurements made on a cranial CT scan).

This may partially explain some of the outcomes observed in studies comparing surgery using a punch technique to incisional methods.⁶⁻⁸ In 2 studies, the extrusion rates with MIPS (12.1% and 15.2%) were higher than those with a linear incision (3.3%), although the difference was not statistically significant (P = .19 and P = .12).⁶,⁷ The implant stability quotient was significantly lower after MIPS, with no clear association observed between the initial implant stability quotient and implant loss.⁶,⁷ Moreover, the majority of implant loss circumstances with MIPS were similar to those in our 2 cases (spontaneous loss or minor trauma).⁷ A recent meta-analysis could not compare implant loss rates, but raw data showed a difference unfavorable to punch techniques, although the significance of this difference could not be established.⁸

Other explanations for failure should be considered in cases of minimally invasive surgery, especially in the absence of placement on a suture. It is possible that the drilling of the hole is

### Main Points

- We report 2 cases of osseointegration failure in bone-anchored implants, likely related to the placement of the implants on a cranial suture.

- To our knowledge, no cases of this type have ever been described.

- We recommend surgeons identify cranial sutures via preoperative CT scans before surgery.

<figure><img src="image_5.png" /><figcaption>**Figure 2.** Volumetric cranial CT scan (A) with magnification (B) on the area of interest (dotted rectangle) showing the implantation site (arrow) at the parieto-occipital suture, as well as its position relative to the soft tissues (C) with a distance of 55 mm from the external auditory canal.</figcaption></figure>
not perfectly perpendicular to the bone plane or that the irrigation of the drilling site is less abundant, leading to bone cellular burns that could compromise healing.

The use of surgical radionavigation or augmented reality techniques could optimize implant placement.¹¹,¹² However, this would come at the cost of significantly increasing the operational procedure burden (duration, anesthesia, etc.), which we believe is rarely justified.

Without necessarily using surgical radionavigation, we encourage preoperative planning if a cranial CT scan is available for the patient (often done as part of the etiological or anatomic assessment). However, the risk-benefit ratio does not seem favorable for performing (or repeating) a CT scan in children to identify the position of sutures, as these radiological examinations may increase the risk of cancer (central nervous system tumors and leukemia).¹³,¹⁴

The placement of a bone-anchored implant on a cranial suture may promote lack of osseointegration and early implant failure. Blind minimally invasive surgery, especially in the absence of pre-operative planning, inherently increases the risk of accidentally positioning the implant on a cranial suture, thereby leading to osseointegration failure. Before proceeding with minimally invasive implant placement, we recommend that surgeons identify cranial sutures using a preoperative CT scan. An alternative is to use an incision technique, which more often allows avoiding implant placement on a suture.

**Data Availability Statement:** The data that support the findings of this study are available on request from the corresponding author.

**Informed Consent:** Informed consent was obtained from the patients who agreed to take part in the study.

**Peer-review:** Externally peer-reviewed.

**Author Contributions:** Concept – M.R.; Design – M.R.; Supervision – C.V., P.T.; Materials – M.R.; Data Collection and/or Processing – M.R., C.B., P.-E.L., P.T.; Analysis and/or Interpretation – M.R., C.B., P.-E.L., C.V., P.T.; Literature Search – M.R.; Writing – M.R., C.B., C.V., P.T.; Critical Review – C.V., P.T.

**Declaration of Interests:** The authors have no conflict of interest to declare.

**Funding:** The authors declared that this study has received no financial support.

## References

1. Vaneeccloo FM, Ruzza I, Hanson JN, et al. The monaural pseud stereophonic hearing aid (BAHA) in unilateral total deafness: a study of 29 patients. *Rev Laryngol Otol Rhinol (Bord).* 2001;122(5): 343-350.

2. House JW, Kutz JW. Bone-anchored hearing Aids: incidence and management of postoperative complications. *Otol Neurotol.* 2007;28(2):213-217. [CrossRef]

3. Saroul N, Gilain L, Montalban A, Giraudet F, Avan P, Mom T. Patient satisfaction and functional results with the bone-anchored hearing aid (BAHA). *Eur Ann Otorhinolaryngol Head Neck Dis.* 2011;128(3): 107-113. [CrossRef]

4. Gordon SA, Coelho DH. Minimally invasive surgery for osseointegrated auditory implants: a Comparison of Linear versus punch techniques. *Otolaryngol Head Neck Surg.* 2015;152(6):1089-1093. [CrossRef]

5. Dumon T, Medina M, Sperling NM. Punch and drill: implantation of bone anchored hearing device through a minimal skin punch incision versus implantation with dermatome and soft tissue reduction. *Ann Otol Rhinol Laryngol.* 2016;125(3):199-206. [CrossRef]

6. Calon TGA, Johansson ML, de Bruijn AJG, et al. Minimally invasive Ponto surgery versus the linear incision technique with soft tissue preservation for bone conduction hearing implants: a multicenter randomized controlled trial. *Otol Neurotol.* 2018;39(7):882-893. [CrossRef]

7. Strijbos RM, Straatman LV, Calon TGA, et al. Long-Term outcomes of the minimally invasive ponto surgery vs. linear incision technique with soft tissue preservation for installation of percutaneous bone conduction devices. *Front Neurol.* 2021;12:632987. [CrossRef]

8. Xiao Q, Gong F, Wang N, Hu W. Punch vs open surgical techniques for placement of bone-anchored hearing implants: a systematic review and meta-analysis of skin reactions and operating time. *Eur Arch Otorhinolaryngol.* 2021;278(9):3171-3180. [CrossRef]

9. Kiringoda R, Lustig LR. A meta-analysis of the complications associated with osseointegrated hearing Aids. *Otol Neurotol.* 2013;34(5):790-794. [CrossRef]

10. Bezdjian A, Smith RA, Thomeer HGXM, Willie BM, Daniel SJ. A systematic review on factors associated with percutaneous bone anchored hearing implants loss. *Otol Neurotol.* 2018;39(10):e897-e906. [CrossRef]

11. Tian X, Gao ZQ, Zhang ZH, Chen Y, Zhao Y, Feng GD. Validation and precision of mixed reality technology in Baha attract implant surgery. *Otol Neurotol.* 2020;41(9):1280-1287. [CrossRef]

12. Shih M, Gitomer SA, Barton G, Liu YCC. Image-guided surgical navigation for bone-conduction hearing device implant placement. *Int J Pediatr Orl.* 2020;139:110392. [CrossRef]

13. Pearce MS, Salotti JA, Little MP, et al. Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. *Lancet.* 2012;380(9840): 499-505. [CrossRef]

14. Foucault A, Ancelet S, Dreuil S, et al. Childhood cancer risks estimates following CT scans: an update of the French CT cohort study. *Eur Radiol.* 2022;32(8):5491-5498. [CrossRef]