Patient and surgical factors
Ninety patients were included in the study. Sixty-three (70%) were male and 27 (30%) were female. Median age was 52 years, range 16–70 years. (Table 1).
Table 1 Demographics and surgical factors Indications for craniectomy included acute subdural haematoma (33 patients), secondary craniectomy for traumatic brain injury with raised intracranial pressure (22 patients), ischaemic stroke (26 patients), intracerebral haemorrhage (3 patients), cerebral abscess (1 patient) and aneurysmal subarachnoid haemorrhage (1 patient). All patients received a prosthetic cranioplasty—89 patients received a custom-made titanium cranioplasty and 1 patient received a PEEK plate (Table 1). Use of prosthetic cranioplasty material is standard practice in our department; therefore, no patients received an autologous cranioplasty.
The average time to last follow-up was 7.7 months (range 0–48). Nine patients did not receive follow-up. This included 3 patients who did not attend their outpatient appointments and 6 patients who died prior to follow-up (Table 1)
Timing of cranioplasty
Of 90 patients, 66 patients (73%) received a late cranioplasty and 24 (27%) received an early cranioplasty.
The median interval between craniectomy and cranioplasty was 13 months [range 3–84] in the late group vs. 54 days [range 33–90] in the early group. No patients in the early group received a cranioplasty procedure before 1 month. Seven patients had a very long interval (longer than 24 months) between craniectomy and cranioplasty due to their initial injury occurring at another centre and the patients then being lost to follow-up before referral to our centre.
All patients in the late group were re-admitted electively for their cranioplasty. In the early group, 22 patients (91%) received a cranioplasty during their primary hospital admission, while undergoing rehabilitation, and 2 patients were re-admitted for the cranioplasty (Table 2).
Table 2 Timing of cranioplasty Timing of the cranioplasty was determined by surgeon preference. At this time, most surgeons were continuing with traditional practice of waiting at least 6 months before performing cranioplasty. However, other surgeons would consider performing a cranioplasty earlier than 3 months based on the degree of recovery from their initial injury and operation, whether the patient had remained as an inpatient within the regional neuroscience centre to receive rehabilitation in the acute trauma rehabilitation ward, and also whether the cranioplasty plate had been manufactured and was ready for implantation. This has led to a selection bias, with the majority of early cranioplasty patients having trauma as their underlying pathology as the stroke patients were often transferred back to their local stroke unit a few days after the craniectomy.
Any significant preoperative disorders were recorded. Two patients were noted to have developed ‘syndrome of the trephined’ and ‘abnormal CSF dynamics’. One received a cranioplasty at 8 months and was included in the late cohort, the other received a cranioplasty at 46 days and was included in the early cohort. There was no significant difference in preoperative clinical condition in the two groups.
Complications
Overall, complications were seen in 25 patients (28%). This included wound or cranioplasty infection (11 patients), hydrocephalus (7 patients), symptomatic pneumocephalus (3 patients), acute post-operative haematoma (2 patients), incompatible cranioplasty plate due to size (1 patient) and cosmetic issues (1 patient).
The complication rate was 5/24 in the early group (21%) and 20/66 in the late cranioplasty group (30%). There was no significant difference between the two groups (P = 0.46, Fisher’s exact test). Infection was defined as either superficial (requiring antibiotics only) or deep infection (requiring plate removal). Overall rate of infection (including superficial and deep infection) occurred in 8% of the early group and 13% of the late group (no significant difference, p > 0.99, Fisher’s exact test). Infection which required plate removal occurred in 8% of the early and 11% of the late group (no significant difference, p > 0.99, Fisher’s exact test). Hydrocephalus requiring ventricular shunting occurred in 8% on the early group and 8% of the late group (no significant difference, p > 0.99, Fisher’s exact test) (Table 3)
Table 3 Complications—early and late group Length of stay
Patients who were admitted electively for a cranioplasty in a separate admission from their craniectomy had a median length of stay of 2 days (range 1–161 days). All patients attended preoperative assessment clinic prior to their admission.
Patients who underwent an early cranioplasty as part of the same admission as their craniectomy, had a median length of stay of 77 days (range 37–112 days). For comparison, we calculated the length of stay for decompressive craniectomy patients who underwent inpatient rehabilitation without an early cranioplasty, and this was found to be 63 days (range 26–178) (Table 4). This difference in length of stay is not statistically significant (P = 0.28), suggesting that performing an early cranioplasty during the same admission does not necessarily prolong the length of stay for patients undergoing inpatient rehabilitation. This only included data for TBI patients, as patients with ischaemic stroke were transferred to their local district general hospital for further rehabilitation.