Skip to main content
Download PDF

Autologous bone fragments for skull reconstruction after microvascular decompression

BMC Surgery volume 22, Article number: 395 (2022) Cite this article

Abstract

Background

Various methods are used to reconstruct the skull after microvascular decompression, giving their own advantages and disadvantages. The objective of this study was to evaluate the efficacy of using autologous bone fragments for skull reconstruction after microvascular decompression.

Methods

The clinical and follow-up data of 145 patients who underwent microvascular decompression and skull reconstruction using autologous bone fragments in our hospital from September 2020 to September 2021 were retrospectively analyzed.

Results

Three patients (2.06%) had delayed wound healing after surgery and were discharged after wound cleaning. No patient developed postoperative cerebrospinal fluid leakage, incisional dehiscence, or intracranial infection. Eighty-five (58.62%) patients underwent follow-up cranial computed tomography at 1 year postoperatively, showed excellent skull reconstruction. And, the longer the follow-up period, the more satisfactory the cranial repair. Two patients underwent re-operation for recurrence of hemifacial spasm, and intraoperative observation revealed that the initial skull defect was filled with new skull bone.

Conclusion

The use of autologous bone fragments for skull reconstruction after microvascular decompression is safe and feasible, with few postoperative wound complications and excellent long-term repair results.

Peer Review reports

Background

Microvascular decompression (MVD) was first proposed by Jannetta [1] and has become the most common surgical procedure for various cranial neurovascular compression syndromes [2, 3]. The surgery is usually done using a suboccipital retrosigmoid approach, with a small bone flap craniotomy performed in most cases [4,5,6]. Because an incomplete skull is associated with postoperative complications such as cerebrospinal fluid leakage, postoperative skull reconstruction is required even for small bone window craniotomy [7]. Materials used to repair cranial defects after MVD usually include autologous bone flaps and artificial biomaterials [8,9,10]. Surgeons favor autologous bone flaps because of their excellent histocompatibility [11, 12]. However, fixation of autogenous bone flaps still requires a metal coupling piece and often results in bone resorption, especially in younger patients [13, 14].

Three artificial biomaterials are available for skull reconstruction: cement pastes, osteoactive biomaterials, and prefabricated polymers [15]. Each has advantages and disadvantages: cement pastes don’t induce the formation of new bone, osteoactive biomaterials allow for the induction of bone formation, while polymers allow for vascular and bone growth without resorption [7]. Although introducing various new biomaterials has brought more options for cranial repair, it almost always increases the cost of care [16].

To our knowledge, there has been no report of cranial repair after MVD using autologous bone fragments, except for our team [17]. The Centre has consistently used the autogenous bone to repair post-MVD bone window defects and has performed long-term follow-up. Therefore, the present study retrospectively analyzed the data of patients who underwent MVD and subsequent skull reconstruction with autologous bone fragments at our center and reported on their postoperative wound complications and long-term outcomes of skull reconstruction.

Methods

Institutional Review Board/Ethics Committee approval was not required for this retrospective analysis of de-identified medicare data. Likewise, patient consent was not applicable to our study. The basic characteristics, imaging data, intraoperative findings, and postoperative management of the included patients were reviewed. A total of 145 patients who underwent MVD and skull reconstruction using autologous bone fragments were included in the study. The basic characteristics of the patients and diseases are summarized in Table 1.

Table 1 Patient basic characteristics and postoperative complications
Full size table

Operative technique

Under general anesthesia, the patient was placed in the lateral position, with the head facing toward the opposite side. A vertical scalp incision of approximately 5 cm through the “star point” was created, and the muscles and connective tissue were separated to reveal the skull surface. After drilling a bur hole with a 9-mm electric drill (Hitachi, Tokyo, Japan), craniectomy was performed using rongeurs to enlarge the diameter of the bur hole to 2 cm. The resultant skull fragments were collected and preserved in a special container.

The dura was closed with watertight sutures after the neurovascular decompression operation was completed and it was confirmed that there was no significant intracranial bleeding (Fig. 1A). Next, a layer of gelatin sponge matching the size of the skull defect was placed over the sutured dura (Fig. 1B). The autologous skull fragments collected during craniotomy were placed so that they evenly covered the gelatin sponge (Fig. 1 C). Finally, the muscle, subcutaneous tissue, and scalp were tightly closed in a layer-by-layer manner.

Fig. 1
figure 1

Intraoperative procedure of skull reconstruction and cranial CT results on the first postoperative day. A The dura was closed with watertight sutures after completion of the intracranial microvascular decompression procedure. B A layer of gelatin sponge was placed over the sutured dura. C The autologous skull fragments were placed so that they evenly covered the gelatin sponge. D, E, F The patient’s cranial CT on the first postoperative day showed that the autologous bone fragments filled in the skull defect evenly (white arrow)

Full size image

Postoperative management and follow-up

The patients underwent a cranial computed tomography (CT) examination on the first postoperative day to exclude postoperative intracranial hemorrhage and check for bone fragment filling (Fig. 1D–F). The wound was checked by a dedicated person from the first postoperative day until discharge, focusing on the presence of wound redness, swelling, and dehiscence.

All patients included in the study underwent two telephone follow-up, 1 month after surgery and at the beginning of this study. Patients were advised to undergo clinical visits, examinations, and cranial CT in the outpatient clinic one year after discharge to check the skull reconstruction. Follow-up focus includes not only focusing on wound healing and cranial repair but also the clinical effects of MVD surgery.

Results

The procedure was completed successfully and safely in all patients, with a mean operative time of 2.14 ± 0.32 h. No mortality or other severe intra- and postoperative complications were observed. Three patients (2.06%) had delayed wound healing after surgery and were discharged after wound cleaning. No patient developed postoperative cerebrospinal fluid leakage, incisional dehiscence, or intracranial infection. Telephone follow-up data obtained at 1 month after discharge showed that no patient had significant wound complications, including the three patients with delayed wound healing during hospitalization.

At the beginning of this study, we followed up all patients again by telephone. The mean last follow-up time after the telephone interview was 11.3 ± 3.19 months (Table 1). The surgical effectiveness of MVD reached 87.59% (n = 127), and no patient developed wound-related complications during follow-up. Two patients were recommended to be readmitted for MVD surgery after 1 and 1.5 years postoperatively because of recurrence of facial spasm, respectively. The second craniotomy showed that the new skull bone had replaced the autologous bone fragments placed during the first surgery (Fig. 2C, D).

Fig. 2
figure 2

Cranial CT and intraoperative findings at one year after skull reconstruction. A, B The skull defect was completely reconstructed on cranial CT one year after the skull reconstruction (white arrow). C, D A second MVD one year later showed that the new skull bone filled the skull defect caused by the previous operation

Full size image

A total of 85 patients returned to our hospital approximately 1 year after surgery for clinical visits, examinations and cranial CT. Clinical visits and examinations revealed that all patients had healed incisions, no significant pain on compression, and palpable skull formation. Skull CT results of different patients showed that all autologous bone fragments had been wholly resorbed. Instead, new bone grows in varying degrees of concentration from around the skull defect until it fills it (Fig. 2 A, B). The remaining patients reported no discomfort at the surgical incision site, which may be why they did not return to the hospital for a repeat cranial CT.

Discussion

With the advancement of microneurosurgical techniques, the size of the bone window required for MVD surgery is gradually decreasing. Studies have reported that a small bone window of about 2 cm is adequate for MVD surgery and obtains the same surgical outcomes as a large bone window [18, 19]. In some institutions, a small bone flap is milled out with a milling tool and fixed with a connecting piece; in others, the bone window is enlarged with a rongeurs and repaired postoperatively with titanium mesh or other artificial bone repair material. However, all of the above methods involve the implantation of a foreign body in the skull and some additional medical costs. Our team used rongeurs to enlarge the bone window during MVD craniotomy and used the collected bone fragments for cranial reconstruction after MVD [17]. It not only avoids the need for foreign body implantation, but also reduces medical costs.

The present study retrospectively analyzed the wound healing after MVD and skull reconstruction using autologous bone fragments in our center. The results showed that only 2.07% of patients had delayed healing, which is lower than the complication rate of 3.7–14.2% reported in other studies [20, 21]. In our opinion, this low complication rate is primarily attributable to the excellent histocompatibility characteristics of autologous bone fragments, which are unmatched by any other allogeneic material [11, 12, 16]. Although an increasing number of allogeneic materials with minimal resistance are being developed and used for skull reconstruction, the occurrence of immune resistance and infection after implantation, which necessitates secondary surgery, is still unavoidable [22, 23].

Secondly, the good results achieved in the present study are also associated with the manipulation in our skull reconstruction. The autologous bone fragments were evenly placed on the epidural gelatin sponge, which not only avoided the occurrence of cerebrospinal fluid leakage, but also effectively reduced the residual wound cavity between the bone window and the dura. This wound cavity is unfavorable for hemodynamic reconstruction at the site of the cranial defect and tends to form aseptic inflammation, increasing the risk of wound complications. Therefore, the reduction of the wound cavity by filling with autologous bone fragments may be another important reason for the lower wound complications in the present study compared with other studies.

In the long-term follow-up of the present study, cranial CT showed that new skull bone had replaced the autologous bone fragments, with complete skull reconstruction at the site of the skull defect. Although the exact mechanism of skull reconstruction by autologous bone fragments is not clear, we believe that it may be associated with functions of bone grafts: osteoconduction, osteoinduction, and osteogenesis [24, 25]. The autologous bone fragments are implanted in close contact with the bone window edge, stimulating the formation of new vessels towards the skull defect site. The relatively loose bone fragments increase the surface area and favor the hemodynamic reconstruction of the skull defect site, providing a favorable environment for skull reconstruction. In addition, stimulation of the autologous bone fragments causes periosteal osteogenesis at the edge of the bone window and extends towards the defect site, which is known as osteoconduction.

Osteoinduction is the process by which mesenchymal stem cells at and around the host site are recruited to differentiate into chondroblasts and osteoblasts. Various inducible proteins and growth factors are recruited through reconstructed hemodynamics to promote bone fragment demineralization, and the demineralized cartilage is then subjected to induced osteogenesis. This dynamic process of bone fragment resorption and remodeling is known as the “crawling replacement" [26,27,28].

Osteogenesis describes the process in which cells from bone fragments survive the transfer to the defect site and form new bone, which is critical in the initial phase of bone repair [29, 30]. Studies have shown that autologous bone fragments contain many active osteoblasts that could be used for skull reconstruction through osteogenesis [31]. In addition, it has also been shown that progenitor cells brought about by hematopoietic reconstruction at the site of the skull defect could also differentiate into osteoblasts for direct osteogenesis [32]. In conclusion, although the mechanism of skull reconstruction by autologous bone fragments remains uncertain, the excellent skull reconstruction outcome deserves clinical promotion.

Combined with the results of this study, we suggest that autologous bone fragments have the following three advantages for repairing cranial defects after MVD. First, the use of a rongeur rather than a milling tool during craniotomy effectively reduces the damage to the dura and sigmoid sinus during the procedure. Secondly, autologous bone fragments fill the overall cranial defect, avoiding the use of other biomaterials including metal connecting pieces, which not only effectively reduces postoperative incision-related complications, but also reduces patient medical costs. Finally, distant cranial CT images and intraoperative findings suggest that the autologous fragmented bone can be resorbed to form new cranial bone for effective cranial repair.

Conclusion

The use of autologous bone fragments for skull reconstruction after MVD results in few wound complications and achieves excellent long-term cranial repair results. Furthermore, the method is convenient and does not increase medical costs.

Availability of data and materials

The data that support the findings of this study are available on request from the corresponding author (NX.X).

Abbreviations

CT:

Computed tomography

GN:

Glossopharyngeal neuralgia

HFS:

Hemifacial spasm

INN:

Intermediate nerve neuralgia

MVD:

Microvascular decompression

TN:

Trigeminal neuralgia

References

  1. Kaufmann AM, Price AV. A history of the Jannetta procedure. J Neurosurg. 2019;132(2):639–46.

    Article  PubMed  Google Scholar 

  2. Li J, Lyu L, Chen C, Yin S, Jiang S, Zhou P. The outcome of microvascular decompression for hemifacial spasm: a systematic review and meta-analysis. Neurosurg Rev. 2022;45(3):2201–10.

    Article  PubMed  Google Scholar 

  3. Araya EI, Claudino RF, Piovesan EJ, Chichorro JG. Trigeminal Neuralgia: basic and clinical aspects. Curr Neuropharmacol. 2020;18(2):109–19.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Zhong J, Zhu J, Sun H, Dou NN, Wang YN, Ying TT, Xia L, Liu MX, Tao BB, Li ST. Microvascular decompression surgery: surgical principles and technical nuances based on 4000 cases. Neurol Res. 2014;36(10):882–93.

    Article  PubMed  Google Scholar 

  5. Lee MH, Jee TK, Lee JA, Park K. Postoperative complications of microvascular decompression for hemifacial spasm: lessons from experience of 2040 cases. Neurosurg Rev. 2016;39(1):151–8.

    Article  PubMed  Google Scholar 

  6. Ma Z, Li M, Cao Y, Chen X. Keyhole microsurgery for trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia. Eur Arch Otorhinolaryngol. 2010;267(3):449–54.

    Article  PubMed  Google Scholar 

  7. Pabaney AH, Reinard KA, Asmaro K, Malik GM. Novel technique for cranial reconstruction following retrosigmoid craniectomy using demineralized bone matrix. Clin Neurol Neurosurg. 2015;136:66–70.

    Article  PubMed  Google Scholar 

  8. Meyer H, Khalid SI, Dorafshar AH, Byrne RW. The materials utilized in cranial reconstruction: past, current, and future. Plast Surg (Oakv). 2021;29(3):184–96.

    Article  Google Scholar 

  9. Wolfson DI, Magarik JA, Godil SS, Shah HM, Neimat JS, Konrad PE, Englot DJ. Bone cement cranioplasty reduces cerebrospinal fluid leak rate after microvascular decompression: a single-institutional experience. J Neurol Surg B Skull Base. 2021;82(5):556–61.

    Article  PubMed  Google Scholar 

  10. Eseonu CI, Goodwin CR, Zhou X, Theodros D, Bender MT, Mathios D, Bettegowda C, Lim M. Reduced CSF leak in complete calvarial reconstructions of microvascular decompression craniectomies using calcium phosphate cement. J Neurosurg. 2015;123(6):1476–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Frautschi RS, Halasa B, Kwiecien G, Krebs J, Recinos V, Onwuzulike K, Rampazzo A, Papay F, Zins JE, Bassiri GB. Reconstruction of secondary calvarial defects with ex situ split calvarial bone grafts: long-term evaluation of outcomes. Plast Reconstr Surg. 2019;143(1):223–33.

    Article  CAS  PubMed  Google Scholar 

  12. Abu-Ghname A, Banuelos J, Oliver JD, Vyas K, Daniels D, Sharaf B. Outcomes and complications of pediatric cranioplasty: a systematic review. Plast Reconstr Surg. 2019;144(3):433e–443e.

    Article  CAS  PubMed  Google Scholar 

  13. Schuss P, Vatter H, Oszvald A, Marquardt G, Imohl L, Seifert V, Guresir E. Bone flap resorption: risk factors for the development of a long-term complication following cranioplasty after decompressive craniectomy. J Neurotrauma. 2013;30(2):91–5.

    Article  PubMed  Google Scholar 

  14. Signorelli F, Giordano M, Caccavella VM, Ioannoni E, Gelormini C, Caricato A, Olivi A, Montano N. A systematic review and meta-analysis of factors involved in bone flap resorption after decompressive craniectomy. Neurosurg Rev. 2022;45(3):1915–22.

    Article  PubMed  Google Scholar 

  15. Chim H, Gosain AK. Biomaterials in craniofacial surgery: experimental studies and clinical application. J Craniofac Surg. 2009;20(1):29–33.

    Article  PubMed  Google Scholar 

  16. Hayward RD. Cranioplasty: don’t forget the patient’s own bone is cheaper than titanium. Br J Neurosurg. 1999;13(5):490–1.

    Article  CAS  PubMed  Google Scholar 

  17. Liu W, Yuan Y, Xiong N, Wang Q, Zhang F, Zhao H, Xu H, Nayaz A, Hendrik P, Sean DJ. Reconstruction of craniectomy for microvascular decompression with autologous particulate bone. J Neurol Surg Part Cent Eur Neurosurg. 2021;82(6):538–43.

    Article  Google Scholar 

  18. Lee MH, Jee TK, Lee JA, Park K. Postoperative complications of microvascular decompression for hemifacial spasm: lessons from experience of 2040 cases. Neurosurg Rev. 2016;39(1):151–8.

    Article  PubMed  Google Scholar 

  19. Huang J, Zhan Y, Li Y, Jiang L, Wang K, Wu Z, Xie Y, Shi Q. The efficacy and safety of < 2 cm micro-keyhole microvascular decompression for hemifacial spasm. Front Surg. 2021;8:685155.

    Article  PubMed  PubMed Central  Google Scholar 

  20. Alford EN, Chagoya G, Elsayed GA, Bernstock JD, Bentley JN, Romeo A, Guthrie B. Risk factors for wound-related complications after microvascular decompression. Neurosurg Rev. 2021;44(2):1093–101.

    Article  PubMed  Google Scholar 

  21. Khan SA, Laulloo A, Vats A, Nath F. Microvascular decompression: incidence and prevention of postoperative CSF leakage in a consecutive series of 134 patients. Br J Neurosurg. 2020;34(4):416–8.

    Article  PubMed  Google Scholar 

  22. Watanabe S, Amagasaki K, Naemura K, Nakaguchi H. Exposure of titanium mesh after cranioplasty for microvascular decompression surgery: two case reports. NMC Case Rep J. 2015;2:132–4.

    Article  PubMed  PubMed Central  Google Scholar 

  23. Maqbool T, Binhammer A, Binhammer P, Antonyshyn OM. Risk factors for titanium mesh implant exposure following cranioplasty. J Craniofac Surg. 2018;29(5):1181–6.

    Article  PubMed  Google Scholar 

  24. Khan SN, Cammisa FPJ, Sandhu HS, Diwan AD, Girardi FP, Lane JM. The biology of bone grafting. J Am Acad Orthop Surg. 2005;13(1):77–86.

    Article  PubMed  Google Scholar 

  25. Bauer TW, Muschler GF. Bone graft materials. An overview of the basic science. Clin Orthop RELAT R. 2000;371(2):10–27.

  26. Prolo DJ, Rodrigo JJ. Contemporary bone graft physiology and surgery. Clin Orthop Relat R. 1985;200(11):322–42.

  27. Barastegui D, Gallardo-Calero I, Rodriguez-Carunchio L, Barrera-Ochoa S, Knorr J, Rivas-Nicolls D, Soldado F. Effect of vascularized periosteum on revitalization of massive bone isografts: An experimental study in a rabbit model. Microsurgery. 2021;41(2):157–64.

    Article  PubMed  Google Scholar 

  28. Noguchi T, Sarukawa S, Tsuchiya Y, Okada N, Hayasaka J, Sasaguri K, Nishino H, Jinbu Y, Mori Y. Evaluation of postoperative changes in vascularized iliac bone grafts used for mandibular reconstruction. Int J Oral Max Surg. 2018;47(8):990–7.

    Article  CAS  Google Scholar 

  29. Motoki DS, Mulliken JB. The healing of bone and cartilage. Clin Plast Surg. 1990;17(3):527–44.

    Article  CAS  PubMed  Google Scholar 

  30. Mulliken JB, Glowacki J. Induced osteogenesis for repair and construction in the craniofacial region. Plast Reconstr Surg. 1980;65:553–60.

    Article  CAS  PubMed  Google Scholar 

  31. Clune JE, Mulliken JB, Glowacki J, Rogers GF, Arany PR, Kulungowski AM, Greene AK. Inlay cranioplasty: an experimental comparison of particulate graft versus bone dust. Plast Reconstr Surg. 2010;126(4):1311–9.

    Article  CAS  PubMed  Google Scholar 

  32. Wang XX, Allen RJJ, Tutela JP, Sailon A, Allori AC, Davidson EH, Paek GK, Saadeh PB, McCarthy JG, Warren SM. Progenitor cell mobilization enhances bone healing by means of improved neovascularization and osteogenesis. In. 2011;128:395–405.

    CAS  Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Author information

Author notes

  1. Yuankun Cai, Xiuling Zhang and Xiaobin Chen contributed equally and are co-first authors

Authors and Affiliations

  1. Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China

    Yuankun Cai, Xuan Dai, Songshan Chai, Guo Li, Zhimin Mei, Jincao Chen & Nanxiang Xiong

  2. Department of Neurology, Xiaogan Hospital Affiliated to Wuhan University of Science and Technology, Xiaogan, Hubei, China

    Xiuling Zhang

  3. Department of Neurosurgery, Wuhan NO. 1 Hospital, Wuhan, Hubei, China

    Xiaobin Chen

  4. School of Biomedical Sciences, LKS Faculty of Medicine, Hongkong University, Hongkong, China

    Joshua Ho

  5. Department of Neurology, Yueyang Central Hospital, Yueyang, Hunan, China

    Luoqing Li

Authors
  1. Yuankun Cai
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Xiuling Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Xiaobin Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Xuan Dai
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Songshan Chai
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Guo Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Zhimin Mei
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Joshua Ho
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Jincao Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Luoqing Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Nanxiang Xiong
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by YC, XZ and XC. The first draft of the manuscript was written by YC and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Corresponding authors

Correspondence to Luoqing Li or Nanxiang Xiong.

Ethics declarations

Ethical approval and consent to participate

All methods and procedures used in this study were performed in accordance with the relevant guidelines such as the Declaration of Helsinki and internal guidelines of the Wuhan University Zhongnan Hospital. As it was this study was a retrospective analysis of de-identified medicare data, the Institutional Review Board/Ethics Committee of Wuhan University Zhongnan Hospital waived informed consent.

Consent for publication

Not applicable.

Competing interests

The authors have no relevant financial or non-financial interests to disclose.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Cai, Y., Zhang, X., Chen, X. et al. Autologous bone fragments for skull reconstruction after microvascular decompression. BMC Surg 22, 395 (2022). https://doi.org/10.1186/s12893-022-01820-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12893-022-01820-8

Keywords

BMC Surgery

ISSN: 1471-2482

Contact us