Multilevel Corpectomy for Subaxial Cervical Spondylodiscitis: Literature Review and Role of Navigation, Intraoperative Imaging and Augmented Reality.

BACKGROUND: Subaxial cervical spine spondylodiscitis represents a real challenge in spine surgery. In later stages multiple spinal metamers can the interested by the pathological infection and the alteration of the spinal stability leading to spinal deformity. There is scant literature on subaxial cervical spondylodiscitis management and especially on ≥three-level cervical corpectomies. The authors conducted a literature search on this specific topic and presented an emblematic case of a patient treated with circumferential cervical fixation and four-level cervicothoracic corpectomy. MATERIALS AND METHODS: A comprehensive literature review was performed using the combined Medical Subject Headings (MeSH) terms (multilevel) AND (sub axial spine OR cervical spine) AND (spine osteomyelitis OR spinal osteomyelitis), to search in the PubMed and Scopus databases. Our case was also included in this literature review. From our literature search the authors selected 13 papers, eight were excluded because they did not match our inclusion criteria (the involvement of only one or two levels, or did not perform corpectomy, discectomy, or cervical spine localization). The authors also presented a 71-year-old patient, in poor general clinical status who underwent several cage repositioning, with a final four-level corpectomy (C5, C6, C7, and T1), expandable C5-T1 cage positioning and C4-T2 anterior plating performed merging augmented reality, neuronavigation and intraoperative imaging. RESULTS: This systematic review included 28 patients treated with ≥ three-level corpectomy (11 patients with three-level corpectomy, 15 patients with four-level corpectomy, and 2 patients with six-level corpectomy), 6 women, 5 men, and 17 not reported specifically, with a mean age of 55.9 years (range: 44-72 years). The combined anterior and posterior approach was taken in all but one case, which was treated with the anterior approach only. In one case of six-level cervicothoracic corpectomy, sternotomy was necessary. All reported patients recovered after surgery, except one who died after nosocomial pneumonia. No major intraoperative complications were reported. Usual postoperative complications include wound hematoma, pneumonia, subsidence, epidural hematoma, dural leakage, dysphagia, soft tissue swelling. The mean follow-up time was 31.9 months (range: 8-110 months). CONCLUSION: According to the literature search performed by the authors, multilevel corpectomies for cervical spinal osteomyelitis is a safe and effective complex surgical procedure, even in extended procedures involving up to six levels or those at the cervicothoracic junction. The use multimodal navigation merging intraoperative imaging acquisition, navigation, and augmented reality may provide useful information during implant positioning in complex and altered anatomy and for assessing the best final result.

Incidental craniovertebral junction schwannoma: Surgical or radiosurgical management?

Craniovertebral junction (CVJ) schwannomas are rare tumors, showing direct involvement of the atlanto-occipital and atlanto-axial joints. Microsurgical removal is the standard of care to improve symptoms and local control, but stereotactic radiosurgery (SRS) is an option. Both, surgery, and SRS, may show risks of severe complications. A 41-year-old male was referred to our department after incidental finding of a right-sided C1 tumor. A CT angiogram with 3D reconstructions showed the close relationship between the tumor and the right vertebral artery (VA). A post-contrast enhancement MRI revealed the presence of an extradural mass, sited at the level of the CVJ, mainly at the level of the right articular mass of C1. After multidisciplinary assessment, involving the gamma-knife and neurosurgical teams, we performed a microsurgical resection of the tumor. Histology confirmed the diagnosis of schwannoma. At 1 year follow-up the patient is stable, with no recurrence of the tumor. CVJ schwannoma's current standard of care is surgical resection, but longitudinal studies are required, and should promoted promptly since the recent introduction of the new version of GKSRS that allow the treatment of CVJ's lesions.

Surgical Management of Craniovertebral Junction Schwannomas: A Systematic Review.

BACKGROUND: Craniovertebral junction (CVJ) schwannomas are rare, with surgery and stereotactic radiosurgery (SRS) being effective yet challenging options. We systematically reviewed the literature on CVJ schwannomas. METHODS: PubMed, Scopus, Web-of-Science, and Cochrane were searched following the PRISMA statement to include studies reporting CVJ schwannomas. Clinical features, management, and outcomes were analyzed. RESULTS: We collected 353 patients from 101 included articles. Presenting symptoms were mostly neck pain (30.3%) and headache (26.3%), with most cranial neuropathies involving the XII (31.2%) and X (24.4%) nerves. Most tumors originated from C2 (30.9%) and XII (29.4%) nerves, being extracranial (45.1%) and intradural-extradural (44.2%). Erosion of C1-C2 vertebrae (37.1%), the hypoglossal canal (28.3%), and/or jugular foramen (20.1%) were noted. All tumors were operated, preferably with the retrosigmoid approach (36.5%), with the far-lateral approach (29.7%) or with the posterior approach and cervical laminectomy (26.9%), far-lateral approaches (14.2%), or suboccipital craniotomy with concurrent cervical laminectomy (14.2%). Complete tumor resection was obtained most frequently (61.5%). Adjuvant post-surgery stereotactic radiosurgery was delivered in 5.9% patients. Median follow-up was 27 months (range, 12-252). Symptom improvement was noted in 88.1% of cases, and cranial neuropathies showed improvement in 10.2%. Post-surgical complications occurred in 83 patients (23.5%), mostly dysphagia (7.4%), new cranial neuropathies (6.2%), and cerebrospinal fluid leak (5.9%). A total of 16 patients (4.5%) had tumor recurrence and 7 died (2%), with median overall survival of 2.7 months (range, 0.1-252). CONCLUSIONS: Microsurgical resection is safe and effective for CVJ schwannomas. Data on SRS efficacy and indications are still lacking, and its role deserves further evaluation.

Posterior epidural intervertebral disc migration and sequestration: A systematic review.

Posterior epidural intervertebral disc migration and sequestration (PEIMS) is a rare and debilitating complication of degenerative disc disease. Radiological differential diagnosis is often challenging, complicating the accurate planning of appropriate treatment strategies. We systematically reviewed the literature on PEIMS, focusing on clinical-radiological features and available treatments. PubMed, Scopus, Web of Science, and Cochrane were searched to include studies reporting clinical data of patients with PEIMS. Clinical characteristics, treatment strategies, and functional outcomes were analyzed. We included 82 studies comprising 157 patients. Median age was 54 years (range, 19-91). PEIMSs occurred spontaneously (49.7%) or acutely in patients with underlying progressive degenerative disc disease (50.3%). The most common symptoms were lower-back pain (77.1%) and radiculopathy (66.2%), mainly involving the L5 nerve root (43.8%). PEIMSs were mostly detected at MRI (93%) and/or CT (7%), frequently located in the lumbar spine (81.5%). Median maximum PEIMS diameter was 2.4 cm (range, 1.2-5.0). Surgical debulking was completed in 150 patients (95.5%), sometimes coupled with decompressive laminectomy (65%) or hemilaminectomy (19.1%). Median follow-up time was 3 months (range, 0.5-36.0). Post-treatment symptomatic improvement was reported in 153 patients (97.5%), with total recovery in 118 (75.2%). All 7 patients (4.5%) who received conservative non-surgical management had total clinical recovery at ≤ 3 months follow-ups. PEIMS is a challenging entity that may severely quality-of-life in patients with degenerative disc disease. Surgical removal represents the gold standard to improve patient's functional status. Spine fusion and conservative strategies proved to be effective in some cases.

Minimally invasive percutaneous anterior odontoid screw fixation: institutional experience with a simple and effective technique.

BACKGROUND: The aim of this paper was to show a novel modified technique to perform minimally invasive anterior odontoid screw fixation. METHODS: Twenty-nine patients with a mean age of 45 years were treated with a modified percutaneous anterior odontoid screw fixation. All patients were affected by type II or rostral shallow type III odontoid fractures. A modified guide tube was used in all these patients, with reduction of soft tissue dissection for percutaneous approach. RESULTS: There were no complications related to the modified technique. Good results and optimal screw placement were achieved in 28 out of 29 patients. Only in 1 patient we observed, after mobilization, screw displacement, probably due to severe osteoporosis. CONCLUSIONS: In our opinion, this modified percutaneous minimally invasive technique for anterior odontoid screw fixation, along with the use of a soft tissue dilator not fixed to the spine, has not yet been reported in literature and is strongly recommended to reduce invasiveness of odontoid screw placement.

A Review of Remote Intracerebral Hemorrhage after Chronic Subdural Hematoma Evacuation.

BACKGROUND: Remote intracerebral hemorrhage (RICH) is a severe complication following chronic subdural hematoma (cSDH) drainage, and only case reports and small case series have been reported to date. The authors present an emblematic patient affected by RICH following cSDH drainage. A systematic review of the literature on diagnosis and management of patients affected by RICH following cSDH evacuation has also been performed. METHODS: A literature search according to the PRISMA statement was conducted using PubMed and Scopus databases with the following Mesh terms: [(remote) AND (intracerebral hemorrhage or cerebral hematoma or cerebral infarction or cerebellar hemorrhage or cerebellar hematoma or cerebellar infarction) AND (chronic subdural hematoma)]. RESULTS: The literature search yielded 35 results, and 25 articles met our inclusion criteria: 22 articles were case reports and 3 were case series including three to six patients. Overall, 37 patients were included in the study. Age was reported in all 37 patients, 26 males (70.3%) and 11 females (29.7%), with a male-to-female ratio of 2.4:1. The mean age at diagnosis was 64.6 years (range: 0.25-86 years). Only in 5 cases (13.5%) did the ICH occur contralaterally to the previously drained cSDH. The rapidity of drainage can lead to several types of intracranial hemorrhages, caused by a too rapid change in the cerebral blood flow (CBF) and/or tears of bridging veins. The average time interval between cSDH drainage and neurologic deterioration was 71.05 hours (range: 0-192 hours). CONCLUSIONS: RICH following cSDH represents a rare occurrence and a serious complication, associated with elevated morbidity. Careful monitoring of drain speed after cSDH evacuation surgery is recommended, and minimally invasive techniques such as twist drill craniostomy are suggested, especially for massive cSDHs.

Thoracic Spinal Angiolipomas: A Systematic Review.

BACKGROUND: Spinal angiolipomas (SAs) are rare, benign tumors, representing 0.0004 to 1.2% of angiolipomas, usually located at the extradural and posterior thoracic level, with multimetameric extension. METHODS: A systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The authors searched on PubMed and Scopus databases for published articles with the Mesh term "spinal angiolipoma" and pertinent associations. Language restriction to English papers was applied. The authors also reported three emblematic cases of patients who underwent surgical resection of spindle-shaped (type IA) and dumbbell-shaped (type II) SAs between 2014 and 2020. RESULTS: Of the 256 retrieved articles, 33 were included in the meta-analysis. These 33 studies, together with our 3 reported cases, included a total of 60 patients, 36 females (60%) and 24 males (40%), with a mean age of 53.12 ± 12.82 years (range: 12-77 years).T5 was the most represented level (22 patients). Usually, the localization of SA was extradural, with 53 patients suffering from spindle-shaped type IA SA (88.3%) and 7 patients from dumbbell-shaped type II SA (11.6%). Almost all patients underwent laminectomy (78.3%) and presented a full recovery of motor deficits (85%). Gross total removal (GTR) was performed in 93.3% of patients. The mean follow-up was of 22.71 ± 21.45 months (range: 2-80 months). There was no documented recurrence at follow-up magnetic resonance imaging in any of the patients. CONCLUSIONS: SAs are rare, benign tumors with a great vascular component that presents a favorable outcome. GTR is the gold standard treatment and usually an adjuvant therapy is not required. Even infiltrative lesions, which are more complex, can be treated successfully with a good prognosis. Dumbbell-shaped SAs must be differentiated from schwannomas and meningiomas, and require different surgical techniques, given the profuse bleeding associated with the attempt of debulking. En block resection is the key to treat these common benign tumors with acceptable blood loss.

Spontaneous sacral fracture with associated acrometastasis of the hand.

BACKGROUND: Acrometastases, secondary tumors affecting oncological patients with systemic metastases, are associated with a poor prognosis. In rare cases, acrometastases may precede establishing the primary tumor diagnosis. CASE DESCRIPTION: A 72-year-old female heavy smoker presented with low back pain, and right lower extremity sciatica/radiculopathy. X-rays, CT, MR, and PET-CT scans documented primary lung cancer with multi-organ metastases and accompanying pathological fractures involving the sacrum (S1) and right 4th digit. She underwent a S1 laminectomy and amputation of the distal phalanx of the right fourth finger. The histological examination documented a poorly differentiated pulmonary adenocarcinoma infiltrating bone and soft tissues in the respective locations. The patient was treated with a course of systemic immunotherapy (i.e. pembrolizumab). At 6-month follow-up, the patient is doing well and can stand and walk without pain. CONCLUSION: Spontaneous sacral fractures may be readily misdiagnosed as osteoporotic and/or traumatic lesions. However, in this case, the additional simultaneous presence of a lytic finger lesion raised the suspicion that these were both metastatic tumors. Such acrometastases, as in this case attributed to a lung primary, may indeed involve the spine.

Primary Extracranial Meningiomas of the Head and Neck.

Meningiomas represent the most common benign histological tumor of the central nervous system. Usually, meningiomas are intracranial, showing a typical dural tail sign on brain MRI with Gadolinium, but occasionally they can infiltrate the skull or be sited extracranially. We present a systematic review of the literature on extracranial meningiomas of the head and neck, along with an emblematic case of primary extracranial meningioma (PEM), which provides further insights into PEM management. A literature search according to the PRISMA statement was conducted from 1979 to June 2021 using PubMed, Web of Science, Google Scholar, and Scopus databases, searching for relevant Mesh terms (primary extracranial meningioma) AND (head OR neck). Data for all patients were recorded when available, including age, sex, localization, histological grading, treatment, possible recurrence, and outcome. A total of 83 published studies were identified through PubMed, Google Scholar, and Scopus databases, together with additional references list searches from 1979 to date. A total of 49 papers were excluded, and 34 manuscripts were considered for this systematic review, including 213 patients. We also reported a case of a 45-year-old male with an extracranial neck psammomatous meningioma with sizes of 4 cm × 3 cm × 2 cm. Furthermore, whole-body 68Ga-DOTATOC PET/CT was performed, excluding tumor spread to other areas. Surgical resection of the tumor was accomplished, as well as skin flap reconstruction, obtaining radical removal and satisfying wound healing. PEMs could suggest an infiltrative and aggressive behavior, which has never found a histopathological correlation with a malignancy (low Ki-67, <5%). Whole-body 68Ga-DOTATOC PET/CT should be considered in the patient's global assessment. Surgical removal is a resolutive treatment, and the examination of frozen sections can confirm the benignity of the lesion, reducing the extension of the removal of healthy tissue surrounding the tumor.

Acrometastases to the Hand: A Systematic Review.

Background and Objectives: The term acrometastases (AM) refers to secondary lesions sited distally to the elbow and knee, representing 0.1% of all bony metastases. By frequency, pulmonary cancer and gastrointestinal and genitourinary tract neoplasms are the most responsible for the reported AM. Improvements in oncologic patient care favor an increase in the incidence of such rare cases. We performed a systematic review of acrometastases to the hand to provide further insight into the management of these fragile patients. We also present a peculiar case of simultaneous acrometastasis to the ring finger and pathological vertebral fracture. Material and Methods: A literature search according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement was conducted using the PubMed, Google Scholar, and Scopus databases in December 2020 on metastasis to the hand and wrist, from 1986 to 2020. MeSH terms included acrometastasis, carpal metastasis, hand metastasis, finger metastasis, phalangeal metastasis, and wrist metastasis. Results: In total, 215 studies reporting the follow-up of 247 patients were analyzed, with a median age of 62 years (range 10-91 years). Overall, 162 out of 247 patients were males (65.6%) and 85 were females (34.4%). The median reported follow-up was 5 months (range 0.5-39). The median time from primary tumor diagnosis to acrometastasis was 24 months (range 0.7-156). Acrometastases were located at the finger/phalanx (68.4%), carpal (14.2%), metacarpal (14.2%), or other sites (3.2%). The primary tumors were pulmonary in 91 patients (36.8%). The average interval from primary tumor diagnosis to acrometastasis varied according to the primary tumor type from 2 months (in patients with mesenchymal tumors) to 64.0 months (in patients with breast cancer). Conclusions: Acrometastases usually develop in the late stage of oncologic disease and are associated with short life expectancy. Their occurrence can no longer be considered rare; physicians should thus be updated on their surgical management and their impact on prognosis and survival.

Difficulty differentiating between a posterior extradural lumbar tumor versus sequestered disc even with gadolinum-enhanced MRI.

BACKGROUND: Differentiating between posterior extradural tumors versus sequestered lumbar disc herniations may be difficult even utilizing contrast-enhanced MR scans. CASE DESCRIPTION: A 49-year-old male acutely presented with an incomplete cauda equine syndrome. When the MRI showed a L4-L5 posterior extradural lesion that enhanced with gadolinium, an urgent left hemilaminectomy was performed. The lesion proved to be a sequestrated disc herniation rather than a tumor. Notably, postoperatively the patient almost completely recovered after 6-month follow-up. CONCLUSION: Even on contrast-enhanced MRI studies, posterior extradural sequestered lumbar disc herniations may mimic tumors.

Roy-Camille Type 3 suicidal jumper's fractures: Case series and review of the literature.

BACKGROUND: Roy-Camille reported only three patients in their Type 3 posttraumatic transverse sacral fracture (TSF) classification. A modified Roy-Camille classification has been already proposed by other authors suggesting further categorization of the TSFs as partially displaced or completely displaced to predict the rate of neurological recovery following lumbopelvic fixation. MATERIALS AND METHODS: We reported three adult cases of surgical fixation of fracture-dislocation (3A and 3B) of the sacrum due to traumatic injuries and submitted to lumbopelvic posterior reconstruction. A case of a 15-year-old male patient affected by Type 3C with vascular pelvic injury was also reported. A comprehensive literature search was performed on evaluation and management of Type 3 TSFs. RESULTS: In Type 3A, there is a minimal anterior dislocation and the reduction is feasible with good chance of recovery. In Type 3B, the anterior dislocation is severe, neurological deficits are present, reduction is difficult, and there is a risk of vascular injury both at the trauma and during the surgical reduction. In Type 3C, the anterior dislocation is massive, and the risk of vascular injury is very high requiring prompt vascular or endovascular treatment. Open reduction and posterior instrumentation are technically feasible in patients affected by Type 3 high TSFs. CONCLUSIONS: In our opinion, a modified Roy-Camille classification could be useful in the assessment of prognostic and therapeutic aspects of such fractures, In our opinion, a modified Roy-Camille classification could help assess the prognostic and therapeutic aspects of such fractures, in which the severity of the dislocation affects the surgical technique, the chance of neurological recovery, and the patient's life expectancy.

Perimedullary arteriovenous fistulas of the craniovertebral junction: A systematic review.

Perimedullary arteriovenous fistulas (PMAVFs) are uncommon vascular malformations, and they rarely occur at the level of the craniovertebral junction (CVJ). The therapeutic management is challenging and can include observation alone, endovascular occlusion, or surgical exclusion, depending on both patient and malformation characteristics. A systematic literature search was conducted using MEDLINE, Scopus, and Google Scholar databases, searching for the following combined MeSH terms: (perimedullary arteriovenous fistula OR dural arteriovenous shunt) AND (craniocervical junction OR craniovertebral junction). We also present an emblematic case of PMAVF at the level of the craniovertebral junction associated to a venous pseudoaneurysm. A total of 31 published studies were identified; 10 were rejected from our review because they did not match our inclusion criteria. Our case was not included in the systematic review. We selected 21 studies for this systematic review with a total of 58 patients, including 20 females (34.5%) and 38 males (65.5%), with a female/male ratio of 1:1.9. Thirty-nine out of 58 patients underwent surgical treatment (67.2%), 15 out of 58 patients were treated with endovascular approach (25.8%), 3 out of 58 patients underwent combined treatment (5.2%), and only 1 patient was managed conservatively (1.7%). An improved outcome was reported in 94.8% of cases (55 out of 58 patients), whereas 3 out of 58 patients (5.2%) were moderately disabled after surgery and endovascular treatment. In literature, hemorrhagic presentation is reported as the most common onset (subarachnoid hemorrhage in 63% and intramedullary hemorrhage in 10%), frequently caused either by venous dilation, due to an ascending drainage pathway into an intracranial vein, or by the higher venous flow rates that can be associated with intracranial drainage. Hiramatsu and Sato stated that arterial feeders from the anterior spinal artery (ASA) and aneurysmal dilations are associated with hemorrhagic presentation. In agreement with the classification by Hiramatsu, we defined the PMAVF of the CVJ as a vascular lesion fed by the radiculomeningeal arteries from the vertebral artery and the spinal pial arteries from the ASA and/or lateral spinal artery. Considering the anatomical characteristics, we referred to our patient as affected by PMAVF, even if it was difficult to precisely localize the arteriovenous shunts because of the complex angioarchitecture of the fine feeding arteries and draining veins, but we presumed that the shunt was located in the point of major difference in vessel size between the feeding arteries and draining veins. PMAVFs of CVJ are rare pathologies of challenging management. The best diagnostic workup and treatment are still controversial: more studies are needed to compare different therapeutic strategies concerning both long-term occlusion rates and outcomes.

Chronic Epidural Hematoma Caused by Traumatic Intracranial Pseudoaneurysm of the Middle Meningeal Artery: Review of the Literature with a Focus on this Unique Entity.

BACKGROUND: Pseudoaneurysms of the middle meningeal artery represent fewer than 1% of all intracranial aneurysms; it can be associated with different patterns of intracranial hemorrhages. A chronic epidural hematoma (CEDH) caused by post-traumatic pseudoaneurysm of the middle meningeal artery (MMA) has not yet been reported. CASE DESCRIPTION: A 17-year-old male patient was referred to our unit after a car accident, with head trauma and presented motor and language deficits. After a brain computed tomography scan that revealed a left temporal epidural hematoma, the patient underwent surgery with complete hematoma drainage and recovery. After 5 months, he developed a chronic epidural hematoma secondary to a pseudoaneurysm of the MMA, as shown by cerebral angiography. We also reviewed the literature to evaluate the state of the art concerning the diagnosis and management of patients affected by CEDH. CONCLUSIONS: Pseudoaneurysms are considered unstable because of the poor support of the aneurysmal wall. They tend to progressively increase in size and ultimately rupture, leading to delayed intracranial bleeding. A univocal definition of the interval of time between the acute head trauma and the diagnosis to classify the CEDH is still debated. To our knowledge, this is the first case described of a CEDH secondary to a pseudoaneurysm of the MMA. In our study we suggest defining CEDHs as extradural hematomas diagnosed and/or treated 21 days or more after a head injury.

Posttraumatic Triple Acute Epidural Hematomas: First Report of Bilateral Synchronous Epidural Hematoma and a Third Delayed.

BACKGROUND: Development of a delayed acute epidural hematoma (DEDH) represents a rare event, characterized by a high mortality rate. It is defined as an extradural bleeding not evident at the first brain computed tomography (CT) scan performed after traumatic brain injury but evidenced by further radiologic evaluations. CASE DESCRIPTION: A 22-year-old male was admitted to our unit after brain injury due to an assault. Immediate brain CT scan revealed a right frontal epidural hematoma (EDH) and a smaller left anterior temporal EDH with multiple, bilateral skull fractures in the frontal, parietal, and temporal bones. Both EDHs were surgically treated in the same session. Another immediate CT scan showed a third left parietal acute DEDH. The patient was retransferred to the operating room for a further left parietal craniotomy and EDH evacuation. The postoperative period was uneventful: the patient effectively improved. After 15 days, the patient left the hospital and was admitted to a rehabilitation center. CONCLUSIONS: To the best of our knowledge, this is the first report of a synchronous acute bilateral EDH with the development of a third DEDH located in a separate site. This finding is certainly related to the presence of multiple and bilateral skull fractures. In our experience, we suggest performing an intraoperative CT scan, if available, to early detect the possible development of DEDH.

Osteointegration in Custom-made Porous Hydroxyapatite Cranial Implants: From Reconstructive Surgery to Regenerative Medicine.

BACKGROUND: Custom-made porous hydroxyapatite (HA) implant (Fin-Ceramica Faenza S.p.A., Italy) is a biomimetic, osteoconductive material. Margin fusion at the bone-implant edge, cell proliferation within implant pores, and osteointegration in an animal model have already been described. CASE DESCRIPTION: Radiological, microtomographical, and histological analyses were performed on two patients who underwent surgical explantation of cranial implants after postoperative complication. Primary devices explanted after 2 years showed areas of newly formed bone strictly osteointegrated with pores of the prosthesis. These prostheses showed a focal zone of resorption in correspondence of the newly formed bone, and no signs of inflammation or cytotoxicity were observed. A back-up prosthesis, explanted from the same patient after 6 months because of an infection, did not show presence of newly formed bone both on the surface and in the internal part of the prosthesis. CONCLUSIONS: Custom-made porous HA implant is an osteoconductive material able to promote osteogenesis, osteointegrate with bone tissue, provide an effective cranial reconstruction, and restore functional features of the skull. However, complete bone healing is still a complex and long process.