Indications and scientific support for supratentorial unilateral decompressive craniectomy for different subgroups of patients: A scoping review

CONTEXT

Even though supratentorial unilateral decompressive craniectomy (DC) has become the gold standard neurosurgical procedure aiming to provide long term relief of intractable intracranial hypertension, its indication has only been validated by high-quality evidence for traumatic brain injury and malignant middle cerebral artery infarction. This scoping review aims to summarize the available evidence regarding DC for these two recognized indications, but also for less validated indications that we may encounter in our daily clinical practice.

MATERIALS AND METHODS

A scoping review was conducted on Medline / Pubmed database from inception to present time looking for articles focused on 7 possible indications for DC indications. Studies' level of evidence was assessed using Oxford University level of evidence scale. Studies' quality was assessed using Newcastle-Ottawa scale for systematic reviews of cohort studies and Cochrane Risk of Bias Tool for randomized controlled trials.

RESULTS

Two randomized trials (level 1b) reported the possible efficacy of unilateral DC and the mitigated efficiency of bifrontal DC in the trauma setting. Five systematic reviews meta-analyses (level 2a) supported DC for severely injured young patients with acute subdural hematoma probably responsible for intraoperative brain swelling, while one randomized controlled trial (level 1b) showed comparable efficacy of DC and craniotomy for ASH with intraoperative neutral brain swelling. Three randomized controlled trials (level 1b) and two meta-analyses (level 1a and 3a) supported DC efficacy for malignant ischemic stroke. One systematic review (level 3a) supported DC efficacy for malignant meningoencephalitis. One systematic review meta-analysis (level 3a) supported DC efficacy for malignant cerebral venous thrombosis. The mitigated results of one randomized trial (level 1b) did not allow to conclude for DC efficacy for intracerebral hemorrhage. One systematic review (level 3a) reported the possible efficacy of primary DC and the mitigated efficacy of secondary DC for aneurysmal subarachnoid hemorrhage. Too weak evidence (level 4) precluded from drawing any conclusion for DC efficacy for intracranial tumors.

CONCLUSION

To date, there is some scientific background to support clinicians in the decision making for DC for selected cases of severe traumatic brain injury, acute subdural hematoma, malignant ischemic stroke, malignant meningoencephalitis, malignant cerebral venous thrombosis, and highly selected cases of aneurysmal subarachnoid hemorrhage.

Decompressive craniectomy incisions: all roads lead to bone

INTRODUCTION

Decompressive craniectomy and craniotomy are among the most common procedures in Neurosurgery. In recent years, increased attention has focused on the relationships between incision type, extent of decompression, vascular supply to the scalp, cosmetic outcomes, and complications. Here, we review the current literature on scalp incisions for large unilateral front-temporo-parietal craniotomies and craniectomies.

METHODS

Publications in the past 50 years on scalp incisions used for front-temporo-parietal craniectomies/craniotomies were reviewed. Only full texts were considered in the final analysis. A total of 27 studies that met the criteria were considered for the final manuscript. PRISMA guidelines were adopted for this study.

RESULTS

Five main incision types have been described. In addition to the question mark incision, other common incisions include the T-Kempe, developed to obtain wide access to the skull, the retroauricular incision, designed to spare the occipital branch, as well as the N-shaped and cloverleaf incisions which integrate with pterional approaches. Advantages and drawbacks, integration with existing incisions, relationships with the main arteries, cosmetic outcomes, and risks of wound complications including dehiscence, necrosis, and infection were assessed.

DISCUSSION

The reverse-question mark incision, despite being a mainstay of trauma neurosurgery, can place the vascular supply to the scalp at risk and favor wound dehiscence and infection. Several incisions, such as the T-Kempe, retroauricular, N-shaped, and cloverleaf approaches have been developed to preserve the main vessels supplying the scalp. Incision choice needs to be carefully weighted based on the patient's anatomy, position and size of main vessels, risk of wound dehiscence, and desired volume of decompression.

Novel hemicraniectomy: Preserving temporal structures in severe traumatic brain injury patients

OBJECTIVE

This study evaluates the efficacy and safety of Novel Hemicraniectomy Technique (NHT) in Severe Traumatic Brain Injury (STBI) patients.

METHODS

A retrospective analysis of 79 STBI patients who underwent decompressive hemicraniectomy was conducted. The study compared 25 patients treated with NHT and 54 patients treated with Classic Decompressive Craniectomy (CDC), focusing on therapeutic effects, complications, intracranial pressure, and prognosis.

RESULTS

NHT resulted in shorter surgery duration (101.4 ± 11.8 min, p = 0.008) and greater decompressive effects (21.4 ± 5.6 mmHg, p = 0.018). It also prevented temporal muscle injury (0.0 %, p = 0.026), superficial temporal artery injury (0.0 %, p = 0.009), and masticatory dysfunction (5.9 %, p = 0.040). However, NHT showed no significant advantages in intracranial pressure normalization time (3.5 ± 0.9 days, p = 0.679), hospital stay length (34.3 ± 10.4 days, p = 0.805), intraoperative blood loss reduction (284.0 ± 82.6 ml, p = 0.190), or Glasgow Outcome Scale (GOS) scores (2.8 ± 0.9, p = 0.814) and prognosis (32.0 %, p = 0.831) compared to CDC.

CONCLUSION

NHT offers shorter surgery duration (101.4 ± 11.8 min vs 107.7 ± 8.2 min), superior decompressive effects (21.4 ± 5.6 mmHg vs 17.7 ± 6.9 mmHg), and better protection of temporal structures, but does not significantly reduce complications or improve prognosis compared to CDC. Prospective studies with larger sample sizes are needed to better understand the potential benefits of NHT in STBI treatment.

Craniectomy size and decompression of the temporal base using the altered posterior question-mark incision for decompressive hemicraniectomy

The altered posterior question-mark incision for decompressive hemicraniectomy (DHC) was proposed to reduce the risk of intraoperative injury of the superficial temporal artery (STA) and demonstrated a reduced rate of wound-healing disorders after cranioplasty. However, decompression size during DHC is essential and it remains unclear if the new incision type allows for an equally effective decompression. Therefore, this study evaluated the efficacy of the altered posterior question-mark incision for craniectomy size and decompression of the temporal base and assessed intraoperative complications compared to a modified standard reversed question-mark incision. The authors retrospectively identified 69 patients who underwent DHC from 2019 to 2022. Decompression and preservation of the STA was assessed on postoperative CT scans and CT or MR angiography. Forty-two patients underwent DHC with the standard reversed and 27 patients with the altered posterior question-mark incision. The distance of the margin of the craniectomy to the temporal base was 6.9 mm in the modified standard reversed and 7.2 mm in the altered posterior question-mark group (p = 0.77). There was no difference between the craniectomy sizes of 158.8 mm and 158.2 mm, respectively (p = 0.45), and there was no difference in the rate of accidental opening of the mastoid air cells. In both groups, no transverse/sigmoid sinus was injured. Twenty-four out of 42 patients in the modified standard and 22/27 patients in the altered posterior question-mark group had a postoperative angiography, and the STA was preserved in all cases in both groups. Twelve (29%) and 5 (19%) patients underwent revision due to wound-healing disorders after DHC, respectively (p = 0.34). There was no difference in duration of surgery. Thus, the altered posterior question-mark incision demonstrated technically equivalent and allows for an equally effective craniectomy size and decompression of the temporal base without increasing risks of intraoperative complications. Previously described reduction in wound-healing complications and cranioplasty failures needs to be confirmed in prospective studies to demonstrate the superiority of the altered posterior question-mark incision.

Novel retro-auricular myocutaneous hemicraniectomy flap: Technical note and cadaveric dissection

Objective

The hemicraniectomy is a common technique used in a variety of pathologies including some traumatic brain injury and malignant stroke. A novel technique of performing hemicraniectomies using a retro-auricular incision can avoid transgressing the temporalis muscle and superficial temporal artery while providing adequate hemicranial exposure.

Methods

This technique was reproduced in a skull base lab using a cadaveric head. The key steps of this approach were illustrated in step-by-step fashion. A post-approach CT scan of the cadaver was performed to evaluate the decompression exposure.

Results

This approach can provide sufficient middle fossa decompression and area of exposure, while preserving the temporalis along with the superficial temporal artery. A step-by-step technical illustration is demonstrated in the present note.

Conclusions

The modified retro-auricular myocutaneous flap is a novel technique in hemicraniectomy which can provide sufficient middle fossa decompression and exposure while sparing the temporalis muscle and superficial temporal artery during the approach.

Clinical Analysis of Microvascular Reconstruction Combined With Decompressive Craniectomy in Patients With Malignant Middle Cerebral Artery Infarctions

PURPOSE

This study aimed to evaluate the safety and efficacy of microvascular reconstruction combined with decompressive craniectomy (DHC) in patients with malignant middle cerebral artery infarctions (MMCA).

METHODS

We searched for patients with MMCA and aged＜60 years old, postoperative survival of more than 3 months, consistent with decompression of bone flap removal. Patients were divided into experimental group and control group according to whether they underwent emergency vascular revascularization within 5 days after onset of ischemic stroke.

RESULTS

A total of sixpatients were included in the treatment group and 12 patients in the control group. The National Institutes of Health Stroke Scale (NIHSS) score of the treatment group was lower than that of the control group seven days after operation, but the difference was not statistically significant; 3 months after surgery, modified ranking scale (mRs) score in the treatment group was lower than that in the control group, the difference was statistically significant (P = 0.002); mRs scores of the treatment group 3 months after surgery were significantly different from those before surgery (P < 0.05), but no such difference was found in the control group.

CONCLUSION

Compared with decompressive craniectomy, open surgical revascularization can improve early cerebral perfusion in MMCA patients, and neurological recovery is better at 3 months after operation. By ensuring that surgeons are properly trained and hospitals are equipped, open surgical revascularization can be a treatment option for patients with MMCA.

Superficial temporal artery injury and delayed post-cranioplasty infection

OBJECTIVE

Complications after cranioplasty after decompressive craniectomy (DC) have been reported to be as high as 40%. The superficial temporal artery (STA) is at substantial risk for injury in standard reverse question-mark incisions that are typically used for unilateral DC. The authors hypothesize that STA injury during craniectomy predisposes patients to post-cranioplasty surgical site infection (SSI) and/or wound complication.

METHODS

A retrospective study of all patients at a single institution who underwent cranioplasty after decompressive craniectomy and who underwent imaging of the head (computed tomography angiogram, magnetic resonance imaging with intravenous contrast, or diagnostic cerebral angiography) for any indication between the two procedures was undertaken. The degree of STA injury was classified and univariate statistics were used to compare groups.

RESULTS

Fifty-four patients met inclusion criteria. Thirty-three patients (61%) had evidence of complete or partial STA injury on pre-cranioplasty imaging. Nine patients (16.7%) developed either an SSI or wound complication after cranioplasty and, among these, four (7.4%) experienced delayed (>2 weeks from cranioplasty) complications. Seven of 9 patients required surgical debridement and cranioplasty explant. There was a stepwise but non-significant increase in post-cranioplasty SSI (STA present: 10%, STA partial injury: 17%, STA complete injury: 24%, P=0.53) and delayed post-cranioplasty SSI (STA present: 0%, STA partial injury: 8%, STA complete injury: 14%, P=0.26).

CONCLUSIONS

There is a notable but statistically non-significant trend toward increased rates of SSI in patients with complete or partial STA injury during craniectomy.

Tissue Healing in Hemicraniectomy

Introduction

Decompressive hemicraniectomy (DHC) is a last-resort treatment for refractory intracranial hypertension. Perioperative morbidity is associated with high risks of wound healing disturbances (WHD). Recently, a retromastoidal frontoparietooccipital (RMF) incision type was performed to avoid healing disturbance due to enhanced tissue flap perfusion compared to the classical reverse “question mark” (“Dandy flap”) incision. The goal of this study was to analyze the details of tissue healing problems in DHC. 

Materials and methods

A total of 60 patients who underwent DHC were retrospectively analyzed. In 30 patients the “Dandy flap” incision (group A) and in 30 patients the RMF incision (group B) was made. Since no evidence-based data for the incision type that favors better wound healing exists, the form of incision was left at the surgeon´s discretion. Documentation of the patients was screened for the incidence of WHD: wound necrosis, dehiscence, and cerebrospinal fluid (CSF) leakage. Patient age, the time interval from surgery until the appearance of WHD, the length of surgeries in minutes, and the indications of the DHC were analyzed. A Chi-square test of independence was performed to examine the relationship between the incision type and the appearance of WHD with the statistical significance level set at p<0.05. The mean age of the patients, the mean time interval from surgery until the occurrence of WHD, and the mean length of the surgery between the two groups were compared using an independent sample t-test with the statistical significance level set at p<0.05.

Results

The most common indication for DHC in both groups was malignant MCA infarction (n=20, 66.6% for group A and n=16, 53.3% for group B). CSF leakage was 20% of the most frequent WHD in each group. Wound necrosis was observed only in group A. Although group B showed 13.3% fewer WHD than group A, this difference was not statistically significant. There was no statistically significant difference in the time range between surgery and the occurrence of WHD between the two groups. The length of surgery in group B was significantly shorter than in group A (120.2 mins vs. 103.7 mins).

Conclusion

A noticeable trend for reduced WHD was observed in the patient group using the RMF incision type although the difference was not statistically significant. We praise that the RMF incision allows an optimized skin-flap vascularization and, thereby, facilitates better wound healing. We were able to show a statistically shorter length of surgery with the RMF incision in contrast to the classic “Dandy flap” incision. Larger multicenter studies should be implemented to analyze and address the major advantages and pitfalls of the routinely applied incision techniques.

Evaluating the retro-auricular incision versus reversed question mark incision and Kempe's 'T-bar' incision for decompressive hemicraniectomy

Background

The proper decompression for hemicraniectomy depends on intraoperative surgical technique, so the skin incision, on the other hand, is an important variable throughout hemicraniectomy, and there are a variety of cutaneous incisions, including the Kempe T shaped, the reversed question mark and the retro-auricular incisions. We aim to compare those three types of incisions and assess their effects on the surgical outcomes regarding the skull defect size, survived beyond 1 week, post-operative complications and mortality rates.

Results

A retrospective study included 180 patients were separated into three age- and sex-matched groups according to the type of incision used for their hemicraniectomy. Data including age, sex, causes of surgery, comorbidities, the incision type, the defect area of the skull, intraoperative time and estimated blood loss were recruited for all patients. The mortality and morbidity rates at 3 months post-surgery were documented for all patients. There was a significant difference in the operative time, and the intraoperative measures of blood loss, and insignificant differences in the surviving rate after 1-week post-surgery among the three group patients. There were significant differences between the first and third patient groups compared to the second group regarding wound complications, while the first and third groups were comparable.

Conclusions

The retro-auricular incision is a safe preferable substitute for the reversed question mark and Kempe T-shaped incisions in decompressive hemicraniectomy, due to the better blood flow maintaining, lower rate of post-operative wound complications.

The Kempe incision for decompressive craniectomy, craniotomy, and cranioplasty in traumatic brain injury and stroke

OBJECTIVE

Decompressive craniectomy (DC) is an effective, lifesaving option for reducing intracranial pressure (ICP) in traumatic brain injury (TBI), stroke, and other pathologies with elevated ICP. Most DCs are performed via a standard trauma flap shaped like a reverse question mark (RQM), which requires sacrificing the occipital and posterior auricular arteries and can be complicated by wound dehiscence and infections. The Ludwig Kempe hemispherectomy incision (Kempe) entails a T-shaped incision, one limb from the midline behind the hairline to the inion and the other limb from the root of the zygoma to the coronal suture. The authors' objective in this study was to define their implementation of the Kempe incision for DC and craniotomy, report clinical outcomes, and quantify the volume of bone removed compared with the RQM incision.

METHODS

A retrospective review of a single-surgeon experience with DC in TBI and stroke was performed. Patient demographics, imaging, and outcomes were collected for all DCs from 2015 to 2020, and the incisions were categorized as either Kempe or RQM. Preoperative and postoperative CT scans were obtained and processed using a combination of automatic segmentation (in Python and SimpleITK) with manual cleanup and further subselection in ITK-SNAP. The volume of bone removed was quantified, and the primary outcome was percentage of hemicranium removed. Postoperative surgical wound infections, estimated blood loss (EBL), and length of surgery were compared between the two groups as secondary outcomes. Cranioplasty data were collected.

RESULTS

One hundred thirty-six patients were included in the analysis; there were 57 patients in the craniotomy group (44 patients with RQM incisions and 13 with Kempe incisions) and 79 in the craniectomy group (41 patients with RQM incisions and 38 Kempe incisions). The mean follow-up for the entire cohort was 251 ± 368 days. There was a difference in the amount of decompression between approaches in multivariate modeling (39% ± 11% of the hemicranium was removed via the Kempe incision vs 34% ± 10% via the RQM incision, p = 0.047), although this did not achieve significance in multivariate modeling. Wound infection rates, EBL, and length of surgery were comparable between the two incision types. No wound infections in either cohort were due to wound dehiscence. Cranioplasty outcomes were comparable between the two incision types.

CONCLUSIONS

The Kempe incision for craniectomy or craniotomy is a safe, feasible, and effective alternative to the RQM. The authors advocate the Kempe incision in cases in which contralateral operative pathology or subsequent craniofacial/skull base repair is anticipated.

The Retroauricular Incision as an Effective and Safe Alternative Incision for Decompressive Hemicraniectomy

BACKGROUND

The reverse question mark (RQM) incision has been traditionally utilized to perform decompressive hemicraniectomies (DHC) to relieve refractory intracranial hypertension. Alternative incisions have been proposed in the literature but have not been compared directly.

OBJECTIVE

To present the retroauricular (RA) incision as an alternative incision that we hypothesize will increase calvarium exposure to maximize the removal of the hemicranium and will decrease wound-related complications compared to the RQM incision.

METHODS

This study is a retrospective review of all DHCs performed at our institution over a span of 34 mo, stratified based on the type of scalp incision. The surface areas of the cranial defects were calculated, normalizing to their respective skull diameters. For those patients surviving beyond 1 wk, complications were examined from both cohorts.

RESULTS

A total of 63 patients in the RQM group and 43 patients in the RA group were included. The average surface area for the RA and RQM incisions was 117.0 and 107.8 cm2 (P = .0009), respectively. The ratio of average defect size to skull size for RA incision was 0.81 compared to 0.77 for the RQM group (P = .0163). Of those who survived beyond 1 wk, the absolute risk for surgical site complications was 14.0% and 8.3% for RQM and RA group (P = .5201), respectively.

CONCLUSION

The RA incision provides a safe and effective alternative incision to the traditional RQM incision used for DHC. This incision affords a potentially larger craniectomy while mitigating postoperative wound complications.

An altered posterior question-mark incision is associated with a reduced infection rate of cranioplasty after decompressive hemicraniectomy

OBJECTIVE

Performing a cranioplasty (CP) after decompressive craniotomy is a straightforward neurosurgical procedure, but it remains associated with a high complication rate. Surgical site infection (SSI), aseptic bone resorption (aBR), and need for a secondary CP are the most common complications. This observational study aimed to identify modifiable risk factors to prevent CP failure.

METHODS

A retrospective analysis was performed of all patients who underwent CP following decompressive hemicraniectomy (DHC) between 2010 and 2018 at a single institution. Predictors of SSI, aBR, and need for allograft CP were evaluated in a univariate analysis and multivariate logistic regression model.

RESULTS

One hundred eighty-six patients treated with CP after DHC were included. The diagnoses leading to a DHC were as follows: stroke (83 patients, 44.6%), traumatic brain injury (55 patients, 29.6%), subarachnoid hemorrhage (33 patients, 17.7%), and intracerebral hemorrhage (15 patients, 8.1%). Post-CP SSI occurred in 25 patients (13.4%), whereas aBR occurred in 32 cases (17.2%). An altered posterior question-mark incision, ending behind the ear, was associated with a significantly lower infection rate and CP failure, compared to the classic question-mark incision (6.3% vs 18.4%; p = 0.021). The only significant predictor of aBR was patient age, in which those developing resorption were on average 16 years younger than those without aBR (p < 0.001).

CONCLUSIONS

The primary goal of this retrospective cohort analysis was to identify adjustable risk factors to prevent post-CP complications. In this analysis, a posterior question-mark incision proved beneficial regarding infection and CP failure. The authors believe that these findings are caused by the better vascularized skin flap due to preservation of the superficial temporal artery and partial preservation of the occipital artery. In this trial, the posterior question-mark incision was identified as an easily and costless adaptable technique to reduce CP failure rates.

Novel Decompressive Hemicraniectomy Technique for Traumatic Brain Injury: Technical Note

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of morbidity and mortality across all age groups. Decompressive hemicraniectomy is the treatment for TBI-related refractory intracranial hypertension. The traditional technique for this procedure can result in wound complications due to injury of the scalp flap's vascular supply, namely the superficial temporal and postauricular arteries.

METHODS

In this technical note we describe our experience using a novel technique that preserves both vascular territories by placing the inferior aspect of the incision posterior to the ear as opposed to anterior to it. This modification has the potential to reduce wound healing complications, especially in those at higher risk, while also reducing operative time by avoiding temporalis muscle incision and closure during procedure.

RESULTS

After performing hospital chart review, a total of 7 patients were found who underwent this hemicraniectomy technique for severe TBI. Of these, 5 patients had this performed on the left side, and 2 patients had this performed on the right side. Six of the patients had an accompanying subdural hematoma, whereas 1 patient had no intracranial hemorrhage present.

CONCLUSIONS

In each case, both the superficial temporal and postauricular arteries were preserved, and rapid healing of the scalp flap occurred. In addition to providing a large bone window to allow the brain to swell, this technique has the potential to reduce complications of wound healing by preserving the vascular supply of the scalp flap and reduce operative times by minimizing temporalis muscle dissection.