Primary brainstem hemorrhage (PBH), commonly referred to as hypertensive brainstem hemorrhage, represents a spontaneous cerebrovascular event occurring in the absence of secondary precipitants such as trauma, vascular malformations, or neoplastic processes [1]. The pathophysiological mechanism underlying PBH is predominantly associated with chronic systemic hypertension, which triggers progressive hyaline degeneration and fibrinoid necrosis of perforating arteries within the brainstem due to sustained hemodynamic stress. This degenerative cascade ultimately results in vessel wall rupture and parenchymal hemorrhage following acute blood pressure surges. While the etiology of some PBH cases may remain elusive, hypertension remains the most prevalent pathogenic factor.

Characterized by devastating clinical outcomes, PBH exhibits exceptionally high case fatality rates exceeding 85% within 30 days, resulting in profound psychological distress and socioeconomic ramifications for affected families [2], [3], [4], [5]. Epidemiological analyses reveal a predilection for middle-aged adults (40-60 years), with incidence rates peaking in this demographic [6], [7]. The clinical presentation is notably heterogeneous, often manifesting as acute brainstem dysfunction syndromes including cranial nerve palsies, motor deficits, and consciousness disturbances [8]. These sequelae contribute to disproportionate healthcare resource utilization, with prolonged intensive care requirements and rehabilitation needs.

Contemporary management paradigms for PBH are bifurcated into surgical intervention and conservative care strategies [9]. However, both modalities present significant therapeutic challenges. Surgical hematoma evacuation is constrained by limited accessibility to deep brainstem structures and heightened risks of perioperative morbidity, while conservative approaches offer no direct hematoma removal and suboptimal neurological recovery rates [10]. Notwithstanding ongoing debates regarding surgical candidacy [11], recent advancements in functional neuroanatomy and technological innovations—including high-resolution neuroimaging, intraoperative neurophysiological monitoring, and minimally invasive surgical platforms—have rekindled interest in surgical interventions as a potentially transformative treatment modality [12].

The advent of minimally invasive neurosurgical techniques has engendered considerable enthusiasm in the management of intracerebral hemorrhages [13], [14], [15]. Emerging evidence from comparative effectiveness studies suggests that these approaches may optimize hematoma clearance efficiency and mitigate surgical insult to eloquent brain regions, although methodologically rigorous clinical trials are required to validate these preliminary findings [8], [16], [17]. The brainstem's critical anatomical location and indispensable physiological roles in regulating vital functions impose unique technical challenges for surgical intervention. Traditional open craniotomy for hematoma evacuation, though historically attempted, is fraught with prohibitive risks of brainstem injury and postoperative complications, leading major guidelines to discourage its routine use [18]. Conversely, conventional MIPD techniques, while advantageous in terms of reduced operative morbidity and shortened procedural duration, are limited by imprecise targeting of hematoma niches, particularly in complex brainstem geometries.

Recent breakthroughs in additive manufacturing technologies, however, have ushered in transformative possibilities for MIPD. Specifically, patient-specific 3D-printed navigation templates enable ultra-precise trajectory planning and real-time intraoperative guidance, overcoming prior limitations in targeting accuracy within complex brainstem anatomy [19], [20], [21], [22]. This technological synergy holds promise for improving procedural efficacy while minimizing iatrogenic injury risks.

Despite ongoing therapeutic challenges in PBH management, the convergence of precision neurosurgery and advanced biomaterial engineering offers unprecedented opportunities for clinical innovation. By integrating 3D-printed stereotactic guidance systems with MIPD, we hypothesize that 3D-printed MIPD improves functional outcomes by enabling precise, low-cost, and widely implementable hematoma evacuation. Ultimately, this study aims to deliver effective solutions for PBH clinical management and guide future research directions.