Craniotomy involves the temporary removal of a section of the cranium to address underlying intracranial pathologies and carries a potential risk of surgical site infections (SSIs). The incidence of post-craniotomy SSIs varies considerably across studies, ranging from 2.2 % to 19.8 %, reflecting inconsistent diagnostic criteria and heterogeneous patient populations [1]. The clinical impact of post-craniotomy SSIs extends beyond immediate morbidity. A UK national survey reported sepsis rates of 31.1 % and mortality rates of 7.6 % associated with these infections [2]. Economic implications are substantial, involving prolonged hospitalisation, additional imaging and surgical interventions, extended antibiotic therapy, and delayed rehabilitation [2], [3]. Risk factors for post-craniotomy SSIs include patient-related, surgical, and postoperative variables [4]. Patient factors encompass diabetes mellitus, immunocompromised states, obesity, and prior radiation therapy. Surgical factors comprise prolonged operative duration (>3.5 h), multiple procedures, frontal or paranasal sinus involvement, and cerebrospinal fluid (CSF) leakage. Postoperative factors include wound complications, hematoma formation, and foreign body presence.

Post-craniotomy SSIs are classified anatomically into three categories: superficial incisional infections affecting skin and subcutaneous tissues, deep incisional infections involving the subgaleal space and bone flap, and organ-space infections including subdural empyema, brain abscess, and meningitis [5], [6]. These classifications are not mutually exclusive, as infections may progress from superficial to deeper anatomical planes [7]. The management depends on the lesion's extent and anatomical location, including administration of oral or intravenous (IV) antibiotics, and surgical intervention including drainage, debridement and removal of the bone flap [8]. During the debridement process, devitalised tissues are removed to eliminate infectious sources. Subsequently, the decision on whether to retain or remove the bone flap is considered, with staged cranioplasty being an option in cases of bone flap removal to address the resulting skull defect [9]. Advocates for bone flap retention emphasise its role in preserving cranial structural integrity, contributing to positive cosmetic outcomes, and safeguarding the brain from potential injury through the maintenance of a protective barrier. However, concerns arise regarding the potential for the retained bone flap to serve as a reservoir for persistent infection, leading to recurrent SSIs, even with prolonged antibiotic therapy. The compromised vascular supply to the bone flap further complicates treatment by impairing the delivery of host defence mechanisms and antibacterial agents [10]. Conversely, bone flap removal introduces challenges, such as the need for additional cranioplasty procedures with their associated procedural and long-term infective risks [11].

Currently, there is limited consensus in the neurosurgical literature regarding the management of post-craniotomy SSIs. This systematic review aims to critically assess existing evidence, to offer insights into the advantages and disadvantages of each approach in the context of post-craniotomy SSIs.