Decompressive hemicraniectomy is often resorted to in cases of severe head injury
to deal with, and sometimes in anticipation of, a refractory raised intracranial pressure
(ICP). With progressively reducing acceptable time interval between the primary surgery
and cranioplasty, concerns regarding trephination syndrome and injury to the unprotected
brain have substantially reduced. However, there still remains the necessity of bone
flap preservation and a second surgery with its monetary and logistic implications
that some patients can ill afford. With a view to devise a surgical technique that
can accomplish the aim of achieving adequate intracranial volume expansion required
to mitigate the raised ICP without having to subject the patient to a second surgery
at a later date, “step ladder expansive cranioplasty” was conceptualized[1] and performed on a patient with acute subdural hematoma (SDH) and was published
in Indian Journal of Neurosurgery as a technical note after 3 months of uneventful follow-up.[2] We have subsequently followed up the patient for 2 years.
Clinical Summary
A 72-year-old man with multiple comorbidities was admitted with history of head injury
with a Glasgow coma scale (GCS) score of E2V2M5, in absence of any lateralizing signs. Noncontrast computed tomography (NCCT) of
the head revealed an acute right-sided fronto-parieto-temporal SDH with a 10.2-mm
midline shift and effacement of the basal cistern ([Fig. 1A], [B]). The patient was taken up for a “single-step ladder cranioplasty,” with written
informed consent from the next of kin. The craniectomy defect in this patient was
12 cm × 8 cm in size. The volume of dural outpouching in this patient, when measured
from the craniectomy margin (using formula 2/3 × surface area of the defect × height
of the dural outpouching from the craniectomy defect) was 141.28 cm[3]. He was discharged from the hospital with a GCS of E4M6V5 and without any focal neurologic deficit. Individual subsequently presented with
generalized tonic-clonic seizures and was detected to have developed a chronic fronto-parieto-temporal
SDH ([Fig. 1C]) requiring a single burr hole and drainage under local anesthesia. Subsequent recovery
has been uneventful. Two years after surgery, he is comfortable with his obvious step
deformity in the scalp ([Fig. 2]), not keen to undergo any corrective surgery for the same. NCCT of the head shows
no feature of implant failure ([Fig. 1D]). There is a near-complete resolution of the cerebrospinal fluid (CSF) hygroma recorded
in the NCCT of the head obtained on third week after surgery ([Fig. 1E]), and the brain appears to have expanded to occupy nearly the entire available space
in the volume-augmented cranium ([Fig. 1F]).
Fig. 1 Single-step ladder expansive cranioplasty: the index case. (A, B) Axial sections of preoperative NCCT scan image of head. (C) Contralateral chronic SDH with significant mass effect evident in 16 weeks postoperative
NCCT image. (D) Intact cranioplasty construct 18 months after surgery showing step ladder expansion achieved by fixing the cranium and the bone flaps on
two opposite surfaces of the titanium miniplates, thereby displacing the bone flap
laterally from its preoperative position. (E) Contralateral CSF hygroma evident in 8 weeks postoperative NCCT of the head. (F) Eighteen months post surgery NCCT of the head.
Fig. 2 Cosmesis: obvious step deformity.
Discussion
The maximum volume expansions achieved in this case was 141.28 cm[3], as compared to the cases of unilateral decompressive hemicraniectomy recorded by
Cavuşoğlu et al and Olivecrona et al to be of 102.7 cm[3] and 109 cm[3], respectively. Though the study by Münch et al recorded 157.6 cm[3] as the maximum volume expansion achieved, the mean volume expansion reported was
92.6 cm[3].[3]
[4]
[5]
The volume-augmented cranium has an expanded surface area to cover and leaving any
open wound or suture line under stress over a craniotomy would have disastrous consequences.
Rotation scalp flap was successfully used to cover the defect.
Conclusion
Step ladder expansive cranioplasty offers a single-stage alternative that reinstates
Monroe Kelley doctrine while achieving an assured intracranial volume augmentation
that can be optimized based on our experience in the future. In patients uncomfortable
with the cosmesis, taking down the construct at a later date will probably be easier
than a routine cranioplasty. Further clinical trial is required to see whether this
case results are reproducible, once a consensus can be achieved on the volume expansion
required to mitigate the raised ICP in different cases.
