|Year : 2010 | Volume
| Issue : 4 | Page : 634--636
Bony reconstruction by reposition of bony chips in suboccipital craniectomy
Forhad Hossain Chowdhury1, Atul Goel2, Raziul Haque1, Shafiqul Islam1, Mainul Haque Sarkar1, Khandkar Ali Kawsar1,
1 Department of Neurosurgery, Dhaka Medical College Hospital, Dhaka, Bangladesh
2 Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai 400 012, Bangladesh
Forhad Hossain Chowdhury
Department of Neurosurgery, Dhaka Medical College Hospital, 32 Bokshibazar, Dhaka-1200
In suboccipital craniectomy where the bone is not repositioned, there may be a significant cosmetic defect due to lack of skull bone in the suboccipital region. It may accompanied by sensory symptoms, including pain. To prevent any cosmetic defect and sensory symptoms we repositioned the bone chips at the craniectomy site in 42 suboccipital craniectomies before the closure of the scalp. At a mean follow-up of 22 months (range: 5-44 months), two patients complained of mild discomfort in the healed wound or of occasional local pain. One patient complained of mild itching at the site. In two patients, bone chips were accumulated at the lower part of the suboccipital craniectomy and failed to form a uniform bone cover at the operated site. In one patient, all bone chips were reabsorbed and there was no bone at the operated site. There was pseudomeningocele formation in one patient. In the rest of the cases there was satisfactory bone coverage at the operated site, both clinically and radiologically. The wound sites were aesthetically acceptable in 40 cases. Our study suggests that in the majority of cases where suboccipital craniotomy is not possible or not done, repositioning of the bone chips at the craniectomy site is associated with satisfactory aesthetic and functional outcome and formation of bone coverage at the operated site.
|How to cite this article:|
Chowdhury FH, Goel A, Haque R, Islam S, Sarkar MH, Kawsar KA. Bony reconstruction by reposition of bony chips in suboccipital craniectomy.Neurol India 2010;58:634-636
|How to cite this URL:|
Chowdhury FH, Goel A, Haque R, Islam S, Sarkar MH, Kawsar KA. Bony reconstruction by reposition of bony chips in suboccipital craniectomy. Neurol India [serial online] 2010 [cited 2023 Mar 22 ];58:634-636
Available from: https://www.neurologyindia.com/text.asp?2010/58/4/634/68682
Access to the posterior cranial fossa lesions has traditionally involved permanent bone removal. ,, But this may lead to cerebrospinal fluid (CSF) leakage, pseudomeningocele, significant cosmetic defect, and sometimes may be associated with discomfort, itching, and pain. ,,, Where possible, osteoplastic craniotomy is the best method to approach the posterior fossa lesion, but most neurosurgeons are more familiar with craniectomy. As restoration of normal contour and function is one of the important aspects in surgery, we attempted reposition of the bone chips at craniectomy site.
Materials and Methods
We studied 42 cases of suboccipital craniectomy done at the Department of Neurosurgery, Dhaka Medical College Hospital and Islami Bank Central Hospital, Kakrail, Dhaka, Bangladesh, from January 2006 to August 2009. Lateral suboccipital craniectomy was done in 32 cases: vestibular schwannoma (n=19) [Figure 1]a and b, petroclival meningioma -(n=3) [Figure 2]a and b, epidermoid tumor (n=4), tentorial meningioma (n=3), and trigeminal neuralgia (n=3). Median suboccipital craniectomy was done in ten cases: cerebeller hemangioblastoma (n=3) and cerebeller pilocytic astrocytoma (n=7). In all the cases, after completion of the intradural procedure, the dura was closed in a watertight fashion with or without graft duroplasty. All bone chips, which we preserved in normal saline during the craniectomy, were repositioned at the craniectomy site in a uniform fashion [Figure 1]b and [Figure 2]b. Except in the first seven cases, all the chips were supported in situ with a thick and broad sheet of Gelfoam before layered closure of the wound. During the follow-up, along with other clinical activities the local site was also examined from the aesthetic point of view and was compared with the opposite normal site where possible (i.e., lateral suboccipital craniectomy). The craniectomy site was palpated deeply to check whether bone was covering the operated site (partially or wholly) or not. Postoperative CT scan was done after five months (or more) of operation to see the status of bone coverage at the operated site [Figure 3] and [Figure 4].
The age range of the patients was 11-71 years. At a mean follow-up of 22 months (range: 5-44 months), two patients complained of mild discomfort in the healed wound or of occasional local pain. One patient complained of mild itching at the local site. In two patients, bone chips were accumulated at the lower part of the suboccipital craniectomy and failed to form a uniform bone cover at the operated site. These two cases were from the first seven cases that were done, where we did not support the bone chips with a sheet of Gelfoam. In one patient, all bone chips were reabsorbed and there was no bone at the operated site; this patient was 71 years old and she had generalized osteoporosis.
There was pseudomeningocele formation in one patient. This patient had been operated thrice before (3 years, 6 years, and 10 years before this operation), with two separate incisions for vestibular schwannoma in another center [Figure 5]. Even during the fourth operation for the recurrent tumor, we found a thin layer of bone covering at the operated site. We preserved the bone pieces (though there was only a very small amount of bone chips) and repositioned them after closure of the dura with a fascial graft (probably the graft was larger than needed).
In the rest of the cases there was, both clinically and radiologically, satisfactory bone coverage at the operated site. The wound site was aesthetically acceptable in 40 cases (except in the case with a pseudomeningocele and in the elderly female patient with osteoporosis). In two patients the bone chips were accumulated at the lower part of the suboccipital craniectomy and failed to form a uniform bone cover at operated site and there was mild defect though it was aesthetically acceptable. In our study, we did not come across any wound infection or bone chips-related osteomyelitis.
Suboccipital exposure is a very common neurosurgical operative approach for the management of different pathological lesions in posterior fossa.  Traditional access to the posterior fossa via either midline or lateral approaches has involved the permanent removal of bone. ,, Many neurosurgeons seem to be reluctant to perform craniotomy. They feel that a suboccipital craniotomy flap is too time-consuming and is not suitable to cope with the high probability of rapid deterioration of clinical status in patients with a posterior fossa lesion. A craniectomy is judged to be the quickest and the most reliable procedure. , Surgeons also consider craniotomy using a craniotome as dangerous procedure in the posterior fossa because of the irregular contour of the inner bone surface and the tight adhesion of the dura to the skull.
Several reports have been published regarding the fashioning of a bone flap for posterior fossa lesions. ,,,, Yasargil and Fox first described a technique for creation and replacement of a bone flap in the posterior fossa.  Missori et al. described the technique of the reconstruction of posterior craniectomy with autologous bone chips.  In adult patients, because of the irregular contour of the inner bone surface and the high probability of dural injury it is an accepted practice to perform craniectomy rather than craniotomy to remove the bone in a piecemeal fashion. , However, neurosurgeons who perform a conventional craniectomy without repositioning autologous bone chips are familiar with patients' complaints of persistent headache and immediate postoperative complications such as CSF leakage and pseudomeningocele. , Aesthetically, there is also the problem of a defect at the operated site. ,, When reconstruction of posterior craniectomy is done with autologous bone chips a layer of bone will form. It will cover and reconstruct the craniectomy site and will make the operated site aesthetically acceptable. 
CSF leakage after posterior fossa surgery is a major problem; this is also associated with infection of the CSF and wound. , We, however, faced no CSF fistula or wound infection. It is logical to assume that repositioning of devascularized bone chips may invite osteomyelitis, with discharging skin sinus formation in the postoperative period. But, fortunately, we did not come across this complication. No such complication has been reported in the literature to date.
The severity of postoperative headache could be reduced by the placement of bone at the original site. , One likely mechanism for headache after the posterior fossa approach is adhesion of cervical musculature to exposed dura at the craniectomy site. ,, The dura of the posterior fossa is very well innervated and headache can result due to traction during neck motion. Insertion of a rigid barrier between the dura and muscle will counter this effect and reduce postoperative headache. 
In the long-term, reconstruction of posterior craniectomy with autologous bone chips has an additional advantage. The presence of the bone coverage makes the second surgery (if needed) much easier and safer, with a diminished risk of incising the dura and injuring the cerebellum during the muscle dissection. 
To conclude that in the majority cases where suboccipital craniotomy is not possible or not done due to some reason, repositioning of the bone chips at the craniectomy site is associated with satisfactory aesthetic and functional outcome, with formation of bone coverage at operated site.
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