Head model dataset for mixed reality navigation in neurosurgical interventions for intracranial lesions.

Mixed reality navigation (MRN) technology is emerging as an increasingly significant and interesting topic in neurosurgery. MRN enables neurosurgeons to "see through" the head with an interactive, hybrid visualization environment that merges virtual- and physical-world elements. Offering immersive, intuitive, and reliable guidance for preoperative and intraoperative intervention of intracranial lesions, MRN showcases its potential as an economically efficient and user-friendly alternative to standard neuronavigation systems. However, the clinical research and development of MRN systems present challenges: recruiting a sufficient number of patients within a limited timeframe is difficult, and acquiring low-cost, commercially available, medically significant head phantoms is equally challenging. To accelerate the development of novel MRN systems and surmount these obstacles, the study presents a dataset designed for MRN system development and testing in neurosurgery. It includes CT and MRI data from 19 patients with intracranial lesions and derived 3D models of anatomical structures and validation references. The models are available in Wavefront object (OBJ) and Stereolithography (STL) formats, supporting the creation and assessment of neurosurgical MRN applications.

A computational modelling tool for prediction of head reshaping following endoscopic strip craniectomy and helmet therapy for the treatment of scaphocephaly.

BACKGROUND: Endoscopic strip craniectomy followed by helmet therapy (ESCH) is a minimally invasive approach for correcting sagittal craniosynostosis. The treatment involves a patient-specific helmet designed to facilitate lateral growth while constraining sagittal expansion. In this study, finite element modelling was used to predict post-treatment head reshaping, improving our comprehension of the necessary helmet therapy duration. METHOD: Six patients (aged 11 weeks to 9 months) who underwent ESCH at Connecticut Children's Hospital were enrolled in this study. Day-1 post-operative 3D scans were used to create skin, skull, and intracranial volume models. Patient-specific helmet models, incorporating areas for growth, were designed based on post-operative imaging. Brain growth was simulated through thermal expansion, and treatments were modelled according to post-operative Imaging available. Mechanical testing and finite element modelling were combined to determine patient-specific mechanical properties from bone samples collected from surgery. Validation compared simulated end-of-treatment skin surfaces with optical scans in terms of shape matching and cranial index estimation. RESULTS: Comparison between the simulated post-treatment head shape and optical scans showed that on average 97.3 ± 2.1 % of surface data points were within a distance range of -3 to 3 mm. The cranial index was also accurately predicted (r = 0.91). CONCLUSIONS: In conclusion, finite element models effectively predicted the ESCH cranial remodeling outcomes up to 8 months postoperatively. This computational tool offers valuable insights to guide and refine helmet treatment duration. This study also incorporated patient-specific material properties, enhancing the accuracy of the modeling approach.

Comparative analysis of GoPro and digital cameras in head and neck flap harvesting surgery video documentation: an innovative and efficient method for surgical education.

BACKGROUND: An urgent need exists for innovative surgical video recording techniques in head and neck reconstructive surgeries, particularly in low- and middle-income countries where a surge in surgical procedures necessitates more skilled surgeons. This demand, significantly intensified by the COVID-19 pandemic, highlights the critical role of surgical videos in medical education. We aimed to identify a straightforward, high-quality approach to recording surgical videos at a low economic cost in the operating room, thereby contributing to enhanced patient care. METHODS: The recording was comprised of six head and neck flap harvesting surgeries using GoPro or two types of digital cameras. Data were extracted from the recorded videos and their subsequent editing process. Some of the participants were subsequently interviewed. RESULTS: Both cameras, set at 4 K resolution and 30 frames per second (fps), produced satisfactory results. The GoPro, worn on the surgeon's head, moves in sync with the surgeon, offering a unique first-person perspective of the operation without needing an additional assistant. Though cost-effective and efficient, it lacks a zoom feature essential for close-up views. In contrast, while requiring occasional repositioning, the digital camera captures finer anatomical details due to its superior image quality and zoom capabilities. CONCLUSION: Merging these two systems could significantly advance the field of surgical video recording. This innovation holds promise for enhancing technical communication and bolstering video-based medical education, potentially addressing the global shortage of specialized surgeons.

Outside Europe.

This chapter illustrates that cranial surgery was not limited to Europe. There was however no contribution to improving knowledge outside Europe until medical science departed for the Arab world.

Head growth in patients with myelomeningocele treated with prenatal and postnatal surgery.

OBJECTIVE: The need for permanent CSF diversion is lower in patients who have undergone prenatal surgery for myelomeningocele (MMC) than in those who have undergone postnatal closure. Differences in brain development and head growth between treatment groups are not known, particularly for those who do not require surgical treatment for hydrocephalus. The objective of this study was to determine differences in head growth and to generate MMC-specific head circumference (HC) growth curves for patients who underwent either prenatal or postnatal surgery. METHODS: The authors retrospectively identified patients from St. Louis Children's Hospital who were treated for MMC between 2016 and 2021. HC data were obtained from birth until the most recent follow-up or hydrocephalus treatment. Nonlinear least-squares regression analysis was performed to fit the data into four models: two-term power, Gompertz, West ontogenetic, and Weibull. Subsequently, the curves were assessed for their utility in predicting hydrocephalus treatment. RESULTS: Sixty-one patients (29 females [47.5%], 25 [41%] underwent prenatal surgery, mean gestational age at birth 36.6 weeks) were included in the study. The Weibull model best fit the HC data (prenatal adjusted R2 = 0.95, postnatal adjusted R2 = 0.95), while the Gompertz model had the worst fit (prenatal adjusted R2 = 0.56, postnatal adjusted R2 = 0.39) across both cohorts. Prenatal MMC repair patients had significantly larger HC measurements than their postnatal repair counterparts. The 50th percentile of the Weibull curve was determined as a useful threshold for hydrocephalus treatment: children with HC measurements that crossed and remained above this threshold were significantly more likely to have hydrocephalus treatment regardless of time of MMC repair (prenatal relative risk [RR] 10.0 [95% CI 1.424-70.220], sensitivity 85.7% [95% CI 0.499-0.984], and specificity 82.4% [95% CI 0.600-0.948]; postnatal RR 4.750 [95% CI 1.341-16.822], sensitivity 90.5% [95% CI 0.728-0.980], and specificity 75.0% [95% CI 0.471-0.924]). The HC growth curves of the MMC patients treated prenatally were significantly larger than the WHO HC curves (p < 0.001). CONCLUSIONS: The Weibull model was identified as the HC growth curve with the best fit for MMC patients and serves as a useful predictor of hydrocephalus treatment. For MMC patients with hydrocephalus, prenatal repair patients fit the model well but postnatal repair patients did not, potentially indicating different mechanisms of hydrocephalus development. Those treated prenatally had significantly larger HC measurements compared with both the general population and those treated postnatally. Further study is needed to understand the long-term cognitive outcomes and optimal management of clinically asymptomatic patients with large HC measurements who were treated prenatally for MMC.

Thickness and design features of clinical cranial implants-what should automated methods strive to replicate?

PURPOSE: New deep learning and statistical shape modelling approaches aim to automate the design process for patient-specific cranial implants, as highlighted by the MICCAI AutoImplant Challenges. To ensure applicability, it is important to determine if the training data used in developing these algorithms represent the geometry of implants designed for clinical use. METHODS: Calavera Surgical Design provided a dataset of 206 post-craniectomy skull geometries and their clinically used implants. The MUG500+ dataset includes 29 post-craniectomy skull geometries and implants designed for automating design. For both implant and skull shapes, the inner and outer cortical surfaces were segmented, and the thickness between them was measured. For the implants, a 'rim' was defined that transitions from the repaired defect to the surrounding skull. For unilateral defect cases, skull implants were mirrored to the contra-lateral side and thickness differences were quantified. RESULTS: The average thickness of the clinically used implants was 6.0 ± 0.5 mm, which approximates the thickness on the contra-lateral side of the skull (relative difference of -0.3 ± 1.4 mm). The average thickness of the MUG500+ implants was 2.9 ± 1.0 mm, significantly thinner than the intact skull thickness (relative difference of 2.9 ± 1.2 mm). Rim transitions in the clinical implants (average width of 8.3 ± 3.4 mm) were used to cap and create a smooth boundary with the skull. CONCLUSIONS: For implant modelers or manufacturers, this shape analysis quantified differences of cranial implants (thickness, rim width, surface area, and volume) to help guide future automated design algorithms. After skull completion, a thicker implant can be more versatile for cases involving muscle hollowing or thin skulls, and wider rims can smooth over the defect margins to provide more stability. For clinicians, the differing measurements and implant designs can help inform the options available for their patient specific treatment.

Flap loss in head and neck reconstruction: Is there a singular cause for failure?

Despite the high success rates reported in head and neck reconstruction, free flap failures continue to persist. Understanding the factors associated with flap loss and improving overall success are paramount. This study aimed to comprehensively assess the factors influencing flap revision and free tissue transfer survival in head and neck reconstruction. The study included 70 patients with defects in the lower two-thirds of the head and neck region and underwent reconstruction using free flaps. Patient age, gender, smoking status, comorbidities and data on the location and aetiology of the defect, the specific type of flap employed, the recipient artery and vein chosen, instances of revision and the overall success of the flap were collected. The investigation aimed to establish correlations between these variables as well as flap success and revision rates. No statistically significant differences were observed in arterial and venous anastomosis revision rates, or flap survival, in relation to variables such as age, gender, flap type, smoking status, comorbidities, recipient artery or vein and the number of vein anastomoses. The malignant tumour group exhibited a lower requirement for arterial revision and a higher flap survival rate compared to the benign tumour group. This study underscores the comparable safety profiles of perforator-based and conventional flaps in head and neck reconstruction. Furthermore, it reveals that patient characteristics are not contraindications for free tissue transfer. Additionally, the quantity of the veins and choice of recipient vessels are flexible and do not significantly impact flap success. The higher rates of flap success in patients with malignant aetiology requires further investigation.

[Repaired four cases of hypopharyngeal combined neck skin defects using a folded supraclavicular flap].

Objective:To evaluate the outcomes following the use of folded supraclavicular flap repaired hypopharyngeal combined neck skin defects. Methods:Folded supraclavicular flap were designed to repaired four cases of hypopharyngeal combined neck skin defects patients. Evaluate their repair effect （3 men,1 woman; mean age:66 years）. Hypopharyngeal fistula from 3.2 cm×1.8 cm to 4.5 cm×3.8 cm,skin defects in the neck from 3.8 cm×2.2 cm to 5.1 cm×4.5 cm. The folded supraclavicular flap from 8 cm×5 cm to 13 cm×9 cm. Results:All flaps survived, head and neck appearance was satisfactory, and no patient experienced a major complication. All patients resumed an oral diet function. No fistula recurrence or stricture developed after 6-19 months of follow-up. Conclusion:The folded supraclavicular flap is a safe and effective flap Repaired for hypopharyngeal combined neck skin defects.

Evaluating Head and Neck Reconstruction Outcomes Proves Difficult-Seeking Improvement in Reporting.

This Viewpoint advocates for the improvement of the quality of head and neck reconstruction studies through accurate depictions of the defect and reconstruction performed.

Is hardware colonization associated with latent hardware complications and removal in maxillomandibular free flap reconstruction?

BACKGROUND: The relationship between hardware colonization, latent hardware complications, and hardware removal remains unclear following osteocutaneous free flap reconstruction of the jaws. METHODS: Retrospective cohort study of all patients undergoing free flap reconstruction of the maxilla or mandible from 2016 to 2021. RESULTS: A total of 240 subjects were included. Hardware colonization was associated with latent hardware complication in bivariate (p ≤ 0.001) and multivariate analysis (p ≤ 0.001). Time to latent hardware complication was 6.87 months earlier in colonized subjects (p ≤ 0.001). Of the 35 subjects undergoing hardware removal, 25 initiated but failed conservative therapy, and resolution of symptoms was achieved in 24 subjects after one operative intervention and 33 subjects after repeat intervention if indicated. CONCLUSIONS: Hardware colonization increases the risk and onset of latent hardware complication. Prompt hardware removal may improve outcomes by leading to faster resolution of symptoms without the burden and cost of conservative therapies.

Use of supermicrosurgery in craniofacial and head and neck soft tissue reconstruction: a systematic review of the literature and meta-analysis.

Supermicrosurgery is an evolving approach in the reconstruction of head and neck (HN) and craniofacial (CF) defects. This systematic review aims to evaluate the use of supermicrosurgery for arterial or combined arterial and venous anastomoses in the reconstruction of HN and CF soft tissue defects, and the associated success, total complication, and reoperation rates. A literature search was conducted on PubMed, Dynamed, DARE, EMBASE, Cochrane, and British Medical Journal (BMJ) electronic databases (PROSPERO ID: CRD42023476825). Nine studies fulfilled the inclusion criteria with 35 patients who underwent soft tissue reconstructive procedures using supermicrosurgery. Twenty-one flaps were performed on 20 patients (57.1%) with the remaining 15 patients (42.9%) undergoing supermicrosurgical replantation. The most common pathology requiring reconstruction was HN trauma (n = 16, 45.7%) followed by malignancy (n = 15, 42.9%). The pooled success rate for supermicrosurgery was 98% (95% CI 90 to 100, p = 1.00; I2 = 0%). The cumulative complication rate across all the studies was 46% (95% CI 13 to 80, p < 0.01; I2 = 0%), and the pooled rate of reoperation was 1% (95% CI 0 to 8, p = 0.23; I2 = 24%). The use of supermicrosurgery for HN and CF soft tissue reconstruction has an overall success rate of 98%, which is commensurate with traditional microsurgery for HN reconstruction. Complication and reoperation rates are comparable to previous literature. This study confirms the feasibility of supermicrosurgery as a safe and reliable reconstructive option for HN and CF defects.

Greater Saphenous Vein Graft Harvest from Anterolateral Thigh Free Flap Incision: A Novel Technique.

The greater saphenous vein can be harvested from the standard incision for an anterolateral free flap and used as a vein graft in complex head and neck reconstruction. Laryngoscope, 134:648-650, 2024.

Novel Clinical Anatomical Consideration of the Superficial and Deep Layers of the Deep Temporal Fascia.

BACKGROUND: The deep temporal fascia provides anchoring during thread lifting, which is a minimally invasive face-lifting procedure. However, anatomical studies involving the deep temporal fascia in addition to effective and safe thread-lifting procedures are scarce. The authors clarified the anatomy of the superficial layer of the deep temporal fascia and its surrounding structure using ultrasonography, histologic sections, and cadaveric dissection to propose an effective thread-lifting procedure guideline. METHODS: The authors included 20 healthy young participants from the Republic of Korea. Real-time, two-dimensional, B-mode ultrasonography was performed. Longitudinal scanning was performed along three vertical lines: the line passing through the jugale, the anterior margin of the condylar process of the mandible, and the midpoint between the jugale and anterior margin of the condylar process. Histologic samples from three fresh adult cadavers were harvested from 2.5 cm above and below the zygomatic arch. Eighteen fresh adult hemifaces of cadavers from the Republic of Korea (six men and three women, aged 67.3 ± 7.2 years) were used to confirm the morphology of the deep temporal fascia. RESULTS: The superficial layer of the deep temporal fascia crossed the zygomatic arch and was connected to the origin of the zygomaticus major muscle at the line passing through the jugale. The superficial layer continued inferiorly to the parotidomasseteric fascia at the line passing through the midpoint and condylar process of the mandible. CONCLUSION: This study yielded the novel anatomy of the superficial layer of the deep temporal fascia, and this anatomical structure may be used for an ideal thread-lifting procedure.

Observing vessel stumps axially: A novel exoscope for end-to-end microvascular anastomosis.

Although many free tissue transfers have been performed, free flap loss can still occur because of vascular compromise. To facilitate microsurgery, we invented the axial-view microscope (aMS), a new type of microscope that can axially visualize vessel stumps. The aMS was combined with an optical microscope, the so-called bird's-eye-view microscope (bMS). Using our aMS, we observed the cross-sections of the following 12 arteries during vascular anastomosis: three deep inferior epigastric arteries, three suprathyroid arteries, two thoracodorsal arteries, two jejunal arteries, one lateral circumflex femoral artery, and one facial artery. For each artery, we measured the vessel height-to-width (H-W) ratio to determine the roundness of the vessel stump. Based on the aMS and bMS, the average H-W ratios were 0.877 ± 0.187 and 0.445 ± 0.172, respectively. The H-W ratio obtained using the aMS was significantly higher than that of the bMS (P < 0.001). Providing the surgeon with a bidirectional view of the vessel stump reduced blind spots at the anastomotic site. In this report, we describe our new microscope and associated clinical cases.

Minimally Invasive Approach to Access Vessels for Microvascular Anastomosis in Head and Neck Reconstruction.

OBJECTIVES: To describe our technique, review indications, and evaluate the outcomes of the minimal access approach for recipient vessel identification in microvascular tissue transfer. METHODS: Retrospective chart review of all patients who underwent microvascular reconstruction using the minimal access technique between 2015 and 2021. RESULTS: We report 236 cases, comprising 214 patients with a mean age of 60.2 years (3-88). The most common primary defect sites were the mandible (22.6%), cranium (14%), maxilla (13.2%), skull base (12.8%), and nose/nasal cavity (10.6%). Indications for free flap reconstruction included head and neck cancer extirpation (32.2%), osteoradionecrosis (29.7%), acquired deformity (14.0%), chronic wound (11.9%) and oral motor dysfunction (7.2%). Free flap donor sites used were the anterolateral thigh (84.3%), fibula (7.2%), and radial forearm (6.4%). Vessels utilized include superficial temporal (49.8%), facial (38.3%), angular (11.1%), and transverse cervical (0.4%). The overall complication rate was 14% (n = 33), with surgical complications at the recipient site accounting for 67.6% (n = 25). Flap failure occurred in 3.4% of procedures. Prior head and neck surgery and free flaps were associated with an increased risk of major recipient site complications (n = 20, p = 0.0257 and n = 14, p = 0.0117, respectively). CONCLUSION: Minimal access techniques allow consistent recipient vessel identification for microvascular-free tissue transfer. These approaches may be utilized in reconstructing a broad range of head and neck defects, are low morbidity, and contribute to an overall shorter length of stay. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:2177-2181, 2024.

Novel Hybrid Technique for Preservation of Frontal Branch of Facial Nerve: Subgaleal Preinterfascial Dissection.

OBJECTIVE: The pterional approach is the workhorse of skull-base neurosurgery, which allows virtual access to any intracranial lesion around the circle of Willis. Preserving the frontotemporal branch of the facial nerve and conserving the temporal muscle's symmetry are fundamental objectives besides the access that can be obtained through this versatile neurosurgical technique. This manuscript proposes a subgaleal preinterfascial dissection, a novel hybrid technique that provides advantages of previously described temporal muscle dissection techniques while preserving the integrity of facial nerve branches and the unobstructed broad pterional region. We describe the subgaleal preinterfascial dissection as a safe and simple to technique to achieve preservation of the facial nerve frontal branches during anterolateral approaches. METHODS: Two cadaveric heads were skillfully dissected and studied to perform a proper subgaleal preinterfascial dissection on both sides of each cadaver. Afterward, the same technique was employed in 108 patients during a pterional approach for different neurosurgical diseases, with a postoperative follow-up of 6 months. RESULTS: None of the 108 patients presented postoperative frontotemporal branch palsy during postoperative follow-up. Likewise, no complications related to the proposed technique were present. CONCLUSIONS: The subgaleal preinterfascial dissection is a reliable, safe technique that may be employed during a pterional approach with an unobstructed surgical view and excellent cosmetic and functional results, preserving the frontotemporal branch of the facial nerve.

Turbocharging as a strategy to boost extended perforator flap vascularity in head and neck reconstruction-A report of two cases.

Perforator flap has been applied as the most common flap for soft tissue defect reconstruction. Here, we presented two cases using turbocharging procedure of perforator to perforator as a salvage strategy. The first case was a 54-year-old male with recurrent squamous cell carcinoma (SCC) in the left buccal area and mouth floor. A 6 × 22 cm posteromedial thigh (PMT) flap was designed for reconstruction. The two eccentric perforators of the PMT flap could not conjoin together during dissection nearby the main pedicle of profunda femoral artery (PFA) resulting in inadequate perfusion. Side branched stump before clipped the branch of distal perforator was preserved, then the proximal perforator was divided and end-to-end anastomosis of side branch of distal perforator was done successfully. The second case was a 52-year-old male underwent wide composite excision of right tongue SCC. After excision, anterolateral thigh (ALT) flap around 7 × 15 cm was harvested from left thigh and two perforators were included which one tiny perforator supplied by the descending branch (DB) and the other major perforator originated from oblique branch (OB) of lateral circumflex femoral artery (LCFA). However, the OB main perforator injury showed inadequate perfusion of flap. We trimmed the injury zone of OB perforator, and shift to re-anastomosis of OB perforators to side branch of DB of LCFA directly. The flap demonstrated excellent perfusion immediately after the operation, and it exhibited complete survival 2 weeks postoperatively. These results indicated that the turbocharging procedure, from perforator to perforator, could serve as a strategy for salvaging perfusion-compromised flaps, especially in cases of eccentric perforators or perforator injury resulting in inadequate perfusion.

Facial Masculinization Surgery: An Analysis of Interest Trends Using Search Term Analysis.

INTRODUCTION: Facial masculinization surgery (FMS) is increasingly popular among cisgender and transgender men. The benefits of FMS are focused on facial identity and have been proven to decrease gender dysphoria in this population. Previous research showed increasing interest in gender affirmation surgery and facial feminization surgery, but the prevalence of FMS has not been explored. It is difficult to find these data based on surgical records alone because institutions do not have standardized methods of reporting and lack publications in the field. Our study aimed to analyze public interest in FMS by using worldwide Google Trends to quantify these trends. METHODS: A worldwide Google Trends search was completed from January 1, 2008, to December 31, 2022, for terms focused on FMS. Then, search terms were analyzed for nonfacial masculinization procedures and were aggregated. Lastly, a PubMed search was conducted for the terms "transgender" and "facial masculinization" from January 1, 2008, to December 31 st , 2022, to compare publication rates. RESULTS: Our data showed an increasing interest in FMS through Google search trends since the year 2008. A similar trend was demonstrated for non-FMS gender-affirming terms. PubMed analysis showed "transgender" medicine publishing rates were approximately 39.65 times greater than "facial masculinization" publishing rates, although "facial masculinization" medicine did produce a positive trend over the study period of approximately 4 publications per year. The medical literature on transgender surgeries rapidly outpaces publications specifically focusing on FMS. CONCLUSION: Our study showed increasing interest in gender affirmation surgery over time, particularly FMS. These increasing trends should encourage greater scientific exploration of FMS and research to properly quantify and assess surgical outcomes in this special population. Additional educational interventions for both the general public and medical providers, to increase awareness of unique challenges that impact this community and highlight changes in health care coverage over time, should be created to keep pace with increasing patient demand and address the physical, systemic, and psychosocial issues faced by people who identify as transgender.