Effectiveness of Temporal Augmentation Using a Calvarial Onlay Graft during Pterional Craniotomy

Temporal Hollowing Causes, Classifications, and Treatment Options: A Systematic Review

BACKGROUND

Recent developments in surgical techniques and grading schemas to treat temporal hollowing necessitate critically assessing their efficacy. This systematic review presents the currently available protocols for temporal hollowing, aimed toward improving the clinical approach, for the benefit of the surgeon and patient.

METHODS

A search was conducted in Pubmed, Embase, and Google Scholar in September 2021 using the key words "temporal hollowing" and "temporal augmentation." Inclusion criteria were English written articles published in peer-reviewed journals that reported an outcome relating to the cause, classification, or procedure used to prevent or correct hollowing in humans.

RESULTS

Of the 413, 966 publications retrieved, 24 met the study inclusion criteria. Twenty-one publications discussed the etiology of temporal hollowing, 12 discussed a classification or grading system for temporal hollowing, and 19 discussed a procedure to prevent or correct temporal hollowing. The most commonly reported etiology for temporal hollowing was iatrogenic (63%). For classifying temporal hollowing severity, visual analogue scales (25%) were most commonly used. Mesh (26%) and autologous fat grafts (26%) were the most popular procedures used to prevent or correct temporal hollowing.

DISCUSSION

We presented the spectrum of temporal hollowing grading schemas and treatment modalities currently published in the field. The use, by a majority of publications, of a grading system based on the subjective judgement of the examiner (either alone or adjunct to imaging results) suggests the need for a more standardized measurement tool. Future studies should investigate a universally-applicable temporal hollowing classification system and its impact on treatment outcomes.

Accuracy of patient-specific temporal implants using PEKK

The main aim of this study was to evaluate the accuracy of immediate CAD/CAM reconstruction of the temporal hollowing following temporalis muscle surgery, using a patient-specific implant (PSI) PEKK model. This case series included ten patients who underwent maxillofacial reconstruction using temporalis muscle flap (TMF). The study involved the preoperative planning and fabrication of the temporal implant using virtual surgical planning software. The planning was based on multislice CT scans, from which DICOM files were used to fabricate a 3D model of the temporalis muscle using polyetherketoneketone (PEKK). The patients were followed up for 12 months, to check for any signs of infection or mobilization, and to assess accuracy. At the end of the follow-up period, all the patients showed acceptance of the external appearance, with no signs of infection or rejection. These customized implants were measured and compared with their original 3D preoperative planning using a point-based analysis. This revealed a mean difference (±SD) of 0.0373 (±0.3036) mm and a median difference (Q1 to Q3) of 0.0809 (-0.2108 to 0.2769) mm. The study demonstrated that a highly accurate duplication of PSIs can be achieved using this template-molding workflow. The use of PEKK PSIs resulted in uneventful healing and esthetic acceptance by the patients and, therefore, is a relevant treatment option when temporal hollowing has to be corrected.

Multidisciplinary Frontotemporal Orbitozygomatic Craniotomy for Spheno-orbital Meningiomas: Ophthalmic and Orbital Outcomes

PURPOSE

Advances in surgical approaches have improved access for total or near-total resection of spheno-orbital meningiomas (SOM). Herein, the outcomes of multidisciplinary resection and reconstruction of SOM via frontotemporal orbitozygomatic craniotomy at a single institution are evaluated.

METHODS

A retrospective chart review was performed of all patients with SOM who underwent joint neurosurgical and oculofacial plastic resection via frontotemporal orbitozygomatic craniotomy between January 1999 and December 2018. Demographic data, clinical presentation, risk factors for meningioma, radiographic imaging, pathology results, postoperative outcomes, and surgical complications were reviewed. The outcome measures assessed included visual acuity, pupillary function, color vision, ocular motility, visual fields, and proptosis.

RESULTS

A total of 48 patients were identified having had multidisciplinary frontotemporal orbitozygomatic craniotomy for SOM of which 43 met inclusion criteria. A mean follow-up period of 23.9 ± 20.4 months (range 1-60) was observed. There were 35 patients who underwent primary resection and 8 patients who had prior surgical resection. The main presenting complaints were proptosis (88%), headache (44%), and reduced vision (12%). Gross total resection was achieved in 15 patients (35%) while near-total or subtotal resection was achieved in the remainder. Histologic analysis revealed World Health Organization grade I meningioma in 72% of tumors, grade II in 23%, and grade III in 5%. Mean visual acuity (Logarithm of the Minimum Angle of Resolution) improved from 0.24 ± 0.46 preoperatively to 0.09 ± 0.13 postoperatively (p = 0.03). Surgery improved proptosis, with a reduction in mean Hertel exophthalmometry from 22.37 ± 3.78 mm to 17.91 ± 3.84 mm (p < 0.001), of which 80% had no residual proptosis or developed subsequent recurrence. Exophthalmic index calculated by radiologic evaluation also improved from a mean preoperative value of 1.32 ± 0.19 to 1.12 ± 0.13 at the 6-month interval after surgery (p < 0.001). Before surgery, 19 (45%) patients had a relative afferent pupillary reaction with improvement in 9 (24%) after surgery. Of the 14 (33%) patients with preoperative ocular motility deficit, 7 (16%) had resolution of ocular motility deficit postoperatively. The most common surgical complications were temporalis muscle atrophy with temporal hollowing (14%), wound infection (7%), neurogenic strabismus secondary to trochlear nerve palsy (5%), restrictive strabismus (5%), and aponeurotic blepharoptosis (5%).

CONCLUSIONS

Multidisciplinary frontotemporal orbitozygomatic for resection of SOM is a safe and effective means of tumor removal. It can provide improved visual acuity and proptosis metrics, as well as relief of optic neuropathy and ocular motility deficits.

Analysis of Factors Associated with Temporal Hollowing after Pterional Craniotomy

Background  Temporal hollowing is a common complication after pterional craniotomy. Etiologies of hollowing are still in debate and inconclusive. The objective of this study is to determine the etiology and predictive factors of temporal hollowing after pterional craniotomy.

Methods  A retrospective study of patients who underwent pterional craniotomy was conducted. Inclusion criteria included older than 18 years, having undergone unilateral pterional craniotomy, and with no craniofacial anomaly or temporal defect. Volumes of bone, temporalis muscle, and extratemporalis layer were calculated.

Results  A total of 51 patients were included. Bone volumes of surgical and nonsurgical sites were 219.12 + 23.02 cm ³ , and 228.39 + 22.76 cm ³ , respectively ( p = 0.04). Difference of bony volume was 9.10 cm ³ (3.99%). Volumes of temporalis muscle in surgical and nonsurgical sites were 12.86 + 3.95 cm ³ , and 18.10 + 6.08 cm ³ , respectively ( p < 0.005). Difference of muscle volume was 5.08 cm ³ (28.32%). Volume of extratemporalis soft tissue in surgical and nonsurgical sites were 11.99 + 5.70 cm ³ , and 17.31 + 7.76 cm ³ , respectively ( p < 0.005). Difference of soft tissue volume was 5.56 cm ³ (31.68%). No statistical significance of the difference of bony, muscle, and soft tissue volumes were found between causes of disease, operative time, and postoperative radiation.

Conclusions  Hollowing after pterional craniotomy is an unavoidable result. Bone, temporalis muscle, and soft tissues are combined etiologies. No predictive factors including age, sex, causes, operative time, radiation, and surgical technique are demonstrated. Volume of temporal area reduction was 19.74 cm ³ . Immediate reconstruction is recommended and volume of reconstruction is calculated from preoperative imaging.

Post-Neurosurgical Temporal Deformities: Various Techniques for Correction and Associated Complications

INTRODUCTION

An irregular craniofacial contour along the temporal fossa, known commonly as 'temporal hollowing deformity,' (THD) can arise from multiple etiologies. In fact, up to half of all patients who undergo neurosurgical pterional dissections develop some form of temporal contour deformities. Unfortunately, temporal hollowing correction remains surgically challenging with many techniques resulting in high rates of failure and/or morbidity.

METHODS

Herein, we describe anatomy contributing to postsurgical temporal deformity as well as time-tested prevention and surgical correction techniques. In addition, a review of 25 articles summarizing various techniques and complication profiles associated with temporal hollowing correction are presented.

RESULTS

Complications included infection, implant malposition, revision surgery, pain, and implant removal because of implant-related complications Augmentation with either autologous fat or dermal filler is associated with the highest number of reported complications, including catastrophic events such as stroke, pulmonary embolism, and death. No such complications were reported with use of alloplastic material, use of autologous bone, or free tissue transfer. Furthermore, careful attention to adequate temporalis muscle resuspension and position remain paramount for stable restoration of craniofacial symmetry.

CONCLUSIONS

Catastrophic complications were associated with injection augmentation of both fat and dermal filler in the temporal region. In contrast, use of alloplastic materials was not found to be associated with any catastrophic complications. As such, for the most severe cases of THD, we prefer to employ alloplastic reconstruction.

Cosmetic Reconstruction of Frontotemporal Depression Using Polyethylene Implant after Pterional Craniotomy

Purpose

Pterional craniotomy is a useful approach for the treatment of a variety of intracranial pathologies. However, it can result in temporal hollowing, which causes significant craniomaxillofacial asymmetry and esthetic deformity. The present study was performed to determine the postoperative outcomes of patients following frontotemporal depression reconstruction using a high-density porous polyethylene (HDPE) implant (Medpor®; Stryker, Kalamazoo, MI) after pterional craniotomy.

Materials and Methods

The patients had undergone reconstruction of frontotemporal depression using Medpor® implants after pterional craniotomy at our medical institution during the period from February 2010 to March 2014. We evaluated the thickness and volume of both the temporalis muscle and Medpor® implant through a retrospective review of the medical records and computed tomography (CT) scans of 92 patients.

Results

The mean temporalis muscle thickness ratio (muscle thickness of the affected side/nonaffected side) was 0.61 ± 0.16. The mean reconstructed temporalis muscle thickness ratio (muscle and Medpor® implant thickness of affected side/muscle thickness of nonaffected side) was 1.15 ± 0.02. The mean temporalis muscle volume ratio (muscle volume of affected side/nonaffected side) was 0.67 ± 0.02. The mean reconstructed temporalis muscle volume ratio (muscle and Medpor® implant volume of affected side/muscle volume of nonaffected side) was 1.18 ± 0.02.

Conclusions

Temporalis muscle thickness and volume were significantly decreased on the affected side after pterional craniotomy. Reconstruction of frontotemporal lesions using Medpor® implants after the pterional approach improved temporal hollowing without additional complications.

Temporal augmentation with calvarial onlay graft during pterional craniotomy for prevention of temporal hollowing

Background

Atrophy of muscle and fat often contributes to temporal hollowing after pterional craniotomy. However, the main cause is from the bony defect. Several methods to prevent temporal hollowing have been introduced, all with specific limitations. Autologous bone grafts are most ideal for cranial defect reconstruction. The authors investigated the effectiveness of bony defect coverage and temporal augmentation using pterional craniotomy bone flap.

Methods

This study was conducted in 100 patients who underwent brain tumor excision through pterional approach from 2015 to 2016. Group 1 underwent pterional craniotomy with temporal augmentation and group 2 without temporal augmentation. In group 1, after splitting the calvarial bone at the diploic space, the inner table was used for covering the bone defect and as an onlay graft for temporal augmentation. The outcome is evaluated by computed tomography at 1-year follow-up.

Results

The mean operative time for temporal augmentation was 45 minutes. The mean follow-up was 12 months. The ratio of temporal thickness of operated side to non-operated side was 0.99 in group 1 and 0.44 in group 2, which was statistically different. The mean visual analogue scale score was 1.77 in group 1 and 6.85 in group 2.

Conclusion

This study demonstrated a surgical technique using autologous bone graft for successfully preventing the temporal hollowing and improved patient satisfaction.