A novel less invasive endoscopic-assisted procedure for complete reduction of low-and high-grade isthmic spondylolisthesis performed by anterior and posterior combined approach.

PURPOSE: The optimal surgical management of low- and high-grade isthmic spondylolisthesis (LGS and HGS -IS) is debated as well as whether reduction is needed especially for high-grade spondylolisthesis. Both anterior and posterior techniques can be associated with mechanical disadvantages as hardware failure with loss of reduction and L5 injury. We purpose a novel endoscopic-assisted technique (Sled technique, ST) to achieve a complete reduction in two surgical steps: first anteriorly through a retroperitoneal approach to obtain the greatest part of correction and then posteriorly to complete reduction in the same operation. METHODS: ST efficacy and complications rate were evaluated through a retrospective functional and radiological analysis. RESULTS: Thirty-one patients, 12 male (38.7%) and 19 female (61.3%), average age: 45.4 years with single level IS underwent olisthesis reduction by ST. Twenty-three IS involved L5 (74.2%), 7 L4 (22.5%) and 1 L3 (3.3%). No intraoperative complications were recorded. One patient required repositioning of a pedicle screw. A significant improvement of functional and radiological parameters (L4-S1 and L5-S1 lordosis) outcomes was recorded (p < 0.001). CONCLUSION: ST provides a complete reduction in the slippage in LGS and HGS. The huge anterior release as well as the partial reduction in the slippage by the endoscopic-assisted anterior procedure, because of the cage is acting as a "guide rail", facilitate the final posterior reduction, always complete in our series, minimizing mechanical stresses and neurological risks. CLINICALTRIALS: gov Identifier: NCT03644407.

The influence of peri-operative depressive symptoms on medium-term spine surgery outcome: a prospective study.

PURPOSE: To investigate the role of depressive symptoms on clinical outcomes in patients undergoing spinal surgery up to 2-year follow-up. METHODS: The study used data from an institutional spine surgery registry (January 2016, through March 2022) to identify patients (> 18 years) undergoing spine surgery. Patients with Oswestry Disability Index (ODI) < 20/100 at baseline or undergoing surgery on the cervical spine or for idiopathic spinal deformity and trauma patients were excluded. The patients were divided into two groups based on the pre-operative Mental Component Summary (MCS) score of the SF-36: depression group (MCS ≤ 35) or non-depression group (MCS > 35). The ODI and MCS scores trajectory were wined over the 24-month post-surgery between groups. Additionally, a secondary subgroup analysis was conducted comparing outcomes between those with depressive symptoms (persistent-depression subgroup) and those without depressive symptoms (never-depression subgroup) at 3 months after surgery. RESULTS: A total of 2164 patients who underwent spine surgery were included. The pre-operative depression group reported higher ODI total scores and lower MCS than the pre-operative non-depression group at all time points (P < 0.001). The persistent-depression subgroup reported higher ODI total scores and lower MCS than the never-depression subgroup at all follow-ups (P < 0.001). CONCLUSION: Functional disability and mental health status improve in patients with depression symptoms undergoing spinal surgery. Despite this improvement, they do not reach the values of non-depressed subjects. Over the 2-year follow-up time, patients with depression show a different trajectory of ODI and MCS. Caregivers should be aware of these results to counsel patients with depression symptoms.

Successful salvage strategy using anterior retroperitoneal approach in failed posterior lumbar interbody fusion. A retrospective analisys on lumbar lordosis and clinical outcome.

OBJECTIVE: Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) are among the most popular surgical options for lumbar interbody fusion. If non-union occurs with consequent pain and reduced quality of life, revision surgery should correct any previous technical errors, avoiding further complications. The aim of this study was to analyze technical advantages, radiological and clinical outcomes of anterior approaches (ALIF) in case of failed PLIF or TLIF. METHODS: Retrospective analysis of consecutive patients with persistent low back pain after failed PLIF/TLIF where salvage ALIF through an anterior retroperitoneal miniopen video-assisted technique was performed. Surgical, clinical and radiological data were analysed. Uni and multivariate statistical analysis were applied. RESULTS: Thirty-six patients (average age: 47.1 years) were included. Mean follow-up was 34.4 months. In 30 patients (83.3%) a posterior surgical step was necessary. Non-union (86.1%), cage migration (5.5%), infection (8.3%) were the causes of revision surgery. In 22 patients (61.1%) the involved level was L5-S1, in 12 patients (33.4%) L4-L5, in 1 patient (2.7%) L3-L4. One patient (2.7%) had two levels (L4-L5 and L5-S1) involved. No major intraoperative complications were recorded. Significant correlation between clinical and radiological outcomes (L4-S1 and L5-S1 lordosis improvement) were observed (postoperative VAS and L5-S1, p = 0.038). CONCLUSIONS: Salvage ALIF is a safe option that can significantly ameliorate residual pain achieving primary interbody stability with an ideal segmental lordosis according to pelvic parameters. The advantages of a naive anterior approach fulfils the main objectives of a revision surgery in order to significantly increase the chances of definitive fusion.

The emerging role of hearing loss rehabilitation in patients with vestibular schwannoma treated with Gamma Knife radiosurgery: literature review.

Stereotactic radiosurgery (SRS) is currently the most common treatment for small- to medium-size vestibular schwannoma (VS). Despite favorable outcome, hearing deterioration still remains an underestimated problem, and the role of hearing rehabilitation is an underinvestigated topic. Among available technologies, cochlear implant (CI) should represent a valid alternative in sporadic VS with single-sided deafness and in neurofibromatosis (NF2) with bilateral profound hearing loss. A literature review of the current clinical data was performed searching scientific literature databases. From all of the articles found, 16 papers were selected. Forty-four subjects treated with radiosurgery (18 male, 19 female, and in 7 cases, sex were not specified; 43 NF2 and 1 sporadic VS) were included in the analysis. Epidemiological, clinical, tumor, treatment, and audiological data were collected. Clinical outcome at last follow-up showed an audiological improvement in 25 of the 44 patients. The audiological outcome was unchanged in 16 cases. Audiological deterioration was recorded in 3 cases. Severity of NF2 phenotype, long history of ipsilateral profound deafness before implantation, progressive tumor growth, and high radiation dose (20 and 40 Gy) were found in patients with a worst audiological outcome. Hearing rehabilitation can improve audiological results for VS patients following SRS in selected cases. Hearing rehabilitation with cochlear implant (CI) in SSD leads to partial restoration of binaural hearing with an improvement in speech comprehension in noise and in sound localization, and partial suppression of subjective incapacitating tinnitus. SRS followed by CI may represent in selected cases a potential emerging option in the management of these patients, aimed at improving their quality of life. Possible implications for the follow-up of these patients are still present, although partially resolved.

Functional and radiological outcome of anterior retroperitoneal versus posterior transforaminal interbody fusion in the management of single-level lumbar degenerative disease.

OBJECTIVE: In this study the authors compared the anterior lumbar interbody fusion (ALIF) and posterior transforaminal lumbar interbody fusion (TLIF) techniques in a homogeneous group of patients affected by single-level L5-S1 degenerative disc disease (DDD) and postdiscectomy syndrome (PDS). The purpose of the study was to analyze perioperative, functional, and radiological data between the two techniques. METHODS: A retrospective analysis of patient data was performed between 2015 and 2018. Patients were clustered into two homogeneous groups (group 1 = ALIF, group 2 = TLIF) according to surgical procedure. A statistical analysis of clinical perioperative and radiological findings was performed to compare the two groups. A senior musculoskeletal radiologist retrospectively revised all radiological images. RESULTS: Seventy-two patients were comparable in terms of demographic features and surgical diagnosis and included in the study, involving 32 (44.4%) male and 40 (55.6%) female patients with an average age of 47.7 years. The mean follow-up duration was 49.7 months. Thirty-six patients (50%) were clustered in group 1, including 31 (86%) with DDD and 5 (14%) with PDS. Thirty-six patients (50%) were clustered in group 2, including 28 (78%) with DDD and 8 (22%) with PDS. A significant reduction in surgical time (107.4 vs 181.1 minutes) and blood loss (188.9 vs 387.1 ml) in group 1 (p < 0.0001) was observed. No significant differences in complications and reoperation rates between the two groups (p = 0.561) was observed. A significant improvement in functional outcome was observed in both groups (p < 0.001), but no significant difference between the two groups was found at the last follow-up. In group 1, a faster median time of return to work (2.4 vs 3.2 months) was recorded. A significant improvement in L5-S1 postoperative lordosis restoration was registered in the ALIF group (9.0 vs 5.0, p = 0.023). CONCLUSIONS: According to these results, interbody fusion is effective in the surgical management of discogenic pain. Even if clinical benefits were achieved earlier in the ALIF group (better scores and faster return to work), both procedures improved functional outcomes at last follow-up. The ALIF group showed significant reduction of blood loss, shorter surgical time, and better segmental lordosis restoration when compared to the TLIF group. No significant differences in postoperative complications were observed between the groups. Based on these results, the ALIF technique enhances radiological outcome improvement in spinopelvic parameters when compared to TLIF in the management of adult patients with L5-S1 DDD.

The emerging role of gamma knife radiosurgery in the management of glossopharyngeal neuralgia.

Glossopharyngeal neuralgia (GPN) represents a rare craniofacial disorder accounting for about 1% of all craniofacial pain syndromes. GPN shares several pathophysiologic and clinical features with the more common trigeminal neuralgia. Medical therapy and microvascular decompression, in case of vascular nerve compression, represented the mainstay of GPN management. Other ablative therapies have been reported to date; however, few data are available because of the rarity of this pain syndrome. Among the ablative procedures, gamma knife radiosurgery (GKRS) has been recently introduced in the management of GPN with good pain control and low complication rates. Authors performed a systematic review of the published literature about GKRS in the management of GPN. Radiosurgical treatment data, pain control and recurrence rate have been analysed and compared. GKRS represented a valuable and effective treatment option for the management of GPN. Pain control and complication rates are better than those reported by other ablative procedures and microvascular decompression; however, future studies should be focused on the long-term efficacy of GKRS.

Long fusions to S1 with or without pelvic fixation can induce relevant acute variations in pelvic incidence: a retrospective cohort study of adult spine deformity surgery.

PURPOSE: The purpose of this study is to verify if any changes occur in pelvic incidence (PI) in adult patients undergoing long fusion to sacrum for spine deformity and to describe the effect of fixation to pelvis on these variations. METHODS: We conducted a cross sectional study. Sixty-six adults patients, 87% females (mean ± SD age: 65.1 ± 7.6 years), undergoing fusion from the thoracic spine to the sacrum for adult spine deformity were included. Patients were divided in two different groups: Group A: sacral fixation alone and Group B: sacral fixation plus pelvis fixation. Pre and postoperative standardized full-standing X-rays were analyzed with measurement of: PI, pelvic tilt (PT), lumbar lordosis (LL) and sagittal vertical axis (SVA). RESULTS: A significant effect of time interaction (preoperative to early postoperative; F = 59.93, F = 44.78 and F = 39.87, all p < 0.001) existed for PT, SS and TK in both groups (all, p < 0.001). After adjustment for patients' age (>65 vs. <65 years), a statistically significant increase of PI was observed in patients >65 years (p = 0.006) in Group A between preoperative and postoperative measurements. All patients in Group B exhibited a decrease in PI from preoperative to postoperative. CONCLUSIONS: Older patients undergoing long fusion to the sacrum without pelvic fixation had an increase in PI after surgery. Conversely, pelvic fixation with hips intraoperatively extended has decreased the value of PI from pre- to early postoperative. These changes could be related to degeneration of the sacroiliac joints causing increased rotational mobility and the magnitude of the differences is in the range of clinical relevance.

Change in pelvic incidence due to sacral stress fracture following multilevel instrumented fusion.

Multilevel-instrumented fusion is a common surgical technique used to treat adult spinal deformity (ASD), but it can occasionally lead to rare complications such as sacral insufficiency fractures. The impact of sacral fractures on spinopelvic parameters, particularly pelvic incidence (PI), has not been thoroughly investigated even though they have been documented in the literature. Here, we present a case of a patient who underwent a Th11-sacrum instrumented fusion for ASD. She underwent a revision surgery 18 months after the first procedure to treat proximal junctional pain brought on by a localised kyphosis of the rods. An asymptomatic sacral fracture was discovered during the radiological evaluation: the PI had increased from 71° to 103° between the 2 surgical procedures.

'Tumour-like' lesion caused by cervical discal instability.

We present the case of a man in his 40s who sought medical attention due to central cord syndrome. MRI findings demonstrated contrast uptake, spinal swelling, syrinx formation and narrowing of the spinal canal. We encountered two potential scenarios:when malignancy is suspected, the patient would undergo a biopsy. However, if the lesion is ultimately determined to be benign, the patient would have been subjected to an avoidable risk of neurological damage associated with the procedure. Conversely, addressing the lesion as a result of a degenerative process (discal instability), performing an anterior approach for interbody fusion with an underlying malignant process could lead to substantial delays in the diagnosis, finally producing a poor outcome. A comprehensive imaging workup was conducted to rule out malignancy. We hypothesised that discal instability was responsible for the observed findings. The patient was successfully treated with anterior cervical decompression and fusion, without complications. Follow-up evaluations confirmed remission of the condition.

The burden of preoperative fear-avoidance beliefs in workers after thoracic and lumbar spine surgery: a 2-year follow-up study.

ABSTRACT: Spinal disorders are the main reasons for sick leave and early retirement among the working population in industrialized countries. When "red flags" are present, spine surgery is the treatment of choice. However, the role of psychosocial factors such as fear-avoidance beliefs in spine surgery outcomes is still debated. The study aims to investigate whether patients presenting high or low levels of fear-avoidance thoughts before the spine surgery reported different surgical results and return-to-work rates over 2 years. From an institutional spine surgery registry, workers surgically treated with a preoperative score in the Oswestry Disability Index (ODI) higher than 20/100 and provided ODI questionnaires, return-to-work status at 3-, 6-, 12-, and 24-month follow-ups were analyzed. A total of 1769 patients were stratified according to the work subscale of the Fear-Avoidance Beliefs Questionnaire (FABQ-W) in high fear (FABQ-W ≥ 34/42) or low fear (FABQ-W < 34/42). Multivariate regression was used to search for preoperative factors, which might interact with FABQ-W. The higher-fear group showed a different recovery pattern, with higher levels of disability according to the ODI (total score, absolute change, frequency of clinically relevant change, and disability categories) and lower return-to-work ratios over the 24-month follow-up. High fear, high disability, greater age, female gender, smoking, and worse physical status at baseline were associated with worse ODI outcomes 2 years after the surgery. In summary, fear-avoidance beliefs significantly influence the speed and the entity of surgical outcomes in the working population. However, the contribution of FABQ-W in predicting long-term disability levels was limited.

Quality Control for Spine Registries: Development and Application of a New Protocol.

Registries are gaining importance both in clinical practice and for research purposes. However, quality control is paramount to ensure that data are consistent and reliable. Quality control protocols have been proposed for arthroplasty registries, but these are not directly applicable to the spine setting. This study aims to develop a new quality control protocol for spine registries. Based on the available protocols for arthroplasty registries, a new protocol for spine registries was developed. The items included in the protocol were completeness (yearly enrollment rate and rate of assessment completion), consistency, and internal validity (coherence between registry data and medical records for blood loss, body mass index, and treated levels). All aspects were then applied to the spine registry of the Institution to verify its quality for each of the 5 years in which the registry has been used (2016-2020). Regarding completeness, the yearly enrollment rate ranged from 78 to 86%; the completion of preoperative assessment from 79% to 100%. The yearly consistency rate varied from 83% to 86%. Considering internal validity, the interclass correlation coefficient ranged from 0.1 to 0.8 for blood loss and from 0.3 to 0.9 for body mass index. The coherency for treated levels ranged from 25% to 82%. Overall, all 3 items showed an improvement over time. All 3 analyzed domains showed good to excellent results. The overall quality of the registered data improved over time.

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment).

Background: Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome. Methods: The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review. Results: From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially. Conclusions: The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Fourth ventricle meningiomas: a rare entity.

Fourth ventricle meningiomas (FVMs) are rare, often misdiagnosed, lesions. To the best of our knowledge, 47 cases have been reported in the literature: we describe our series of three cases treated at our Institution, focusing on some diagnostic tips and intraoperative features of these tumours. Our three patients have a history of headache. Gait disturbances, vomiting and/or diplopia complicated the clinical picture before the referral at our Department. The operations were uneventful, and the patients fully recovered from neurological symptoms. They are free of recurrence at a median follow-up of 19 years. FVMs are rare lesions, which are difficult to differentiate preoperatively from the much more common ependymomas. A preoperative distinction would be extremely advantageous: indeed, although both tumours share similar radiological and clinical patterns, they clearly differ as to surgical difficulty and outcome. In fact, meningiomas are comparatively easier to remove, granting better clinical results.

Surgical and Radiologic Prognostic Factors in Intramedullary Spinal Cord Lesions.

OBJECTIVE: The present study aimed to perform a comprehensive data analysis of 47 consecutive patients treated in 8 years and to observe how clinical, radiologic, and surgical factors affect early and long-term outcomes, recurrence rate, and survival. METHODS: Clinical, radiologic, and surgical data were collected retrospectively from the review of a prospectively collected database. The neurologic disability was evaluated according to the modified Rankin Scale (mRS). Radiologic data were obtained by direct measurement performed on magnetic resonance imaging (MRI). Univariate and multivariate statistical analysis was performed. RESULTS: From 2008 to 2016, 47 consecutive patients underwent microsurgical resection of intramedullary lesions (28 males and 19 females; mean age, 41.2 years). Ependymoma (53.2%), astrocytoma (14.9%), hemangioblastoma (14.9%), and cavernous angioma (6.4%) were the most frequent tumor histology. The mean follow-up duration was 69.3 months. Gross total tumor resection was performed in 80.8% of cases. Forty-two patients (89.4%) were alive at last follow-up. Five-year overall survival and recurrence-free survival were 92% and 82%, respectively. CONCLUSIONS: Among the examined variables, age seemed to strongly correlate with outcomes; better chances of recovery and a good postoperative outcome were observed in younger patients. Surfacing lesions had a better early functional outcome than did intramedullary located lesions. Patients' preoperative neurologic and functional status (mRS score ≤2) had a significant impact on late neurologic outcome. Progression-free survival correlated with the extent of tumor resection. Surgery should probably be performed before patients' neurologic decline, aiming to achieve maximal resection without compromising patients' quality of life.

New Trends in Spinal Surgery: Less Invasive Anatomical Approach to the Spine. The Advantages of the Anterior Approach in Lumbar Spinal Fusion.

AIM: To describe the history of the anterior approach to the lumbar spine from the beginning to the minimal invasive techniques that the authors have developed, and to discuss its advantages and drawbacks. MATERIAL AND METHODS: The authors collected published data on the evolution of the anterior approach in the lumbar spine, and described its potential in different pathologies focusing on minimally invasive techniques. RESULTS: Several successful techniques of anterior lumbar approach have been developed over the years, leading to a progressive less invasive anatomical exposure of the spine. Anterior approaches of the lumbar spine gained popularity as an alternative to posterior routes in the management of tumors, infections, traumas, degenerative or deformity diseases and as a salvage procedure after posterior surgery. CONCLUSION: Advantages of the retroperitoneal anterior approach of the lumbar spine are well accepted: it preserves the anatomical structures of the abdomen and posterior tension band, avoiding muscle dissection. The implantation of lordotic cages with larger footprint improves local lordosis and fusion rate even in revision surgery. Drawbacks of traditional retroperitoneal approaches may be: vascular injury, deep venous thrombosis, risk of retrograde ejaculation in male in case of L5-S1 dissection. Therefore, several minimal invasive techniques have been developed to decrease the risks related to the traditional approaches. However, a long learning curve is required to achieve good skills and to manage possible technical concerns and complications.

Multimodal Management of Metastatic Malignant Meningiomas: The Role of Radiosurgery in Long-Term Local Control.

BACKGROUND: Metastatic meningiomas (MMs) are rare (0.1 of 100 cases). Their treatment requires a multimodal approach, with surgery, radiotherapy, chemotherapy, and radiosurgery, which allows a long-term local control (LC) and an extension of free survival. In this study, the authors performed a review of the literature and reported 2 cases of patients affected by extracranial MMs, with long-term follow-up. CASE DESCRIPTION: Case 1: A 48-year-old woman was admitted for resection of an extra-axial falx lesion (meningioma G1). After 2 years, the lesion got a local recurrence, resected with a histologic diagnosis of meningioma G3. During the next 9 years, the patient underwent 5 Gamma Knife radiosurgery (GKRS) procedures for local recurrence. At 56 years, she was readmitted for a surgical local recurrence (histologic definition: anaplastic meningioma G3). At the age of 62, the patient underwent a right lobectomy for a lung mass (histologic diagnosis: anaplastic meningioma G3). After that, multiple lesions at soma L5 and adrenal gland were discovered and then monitored. Case 2: A 48-year-old woman was operated for a lesion involving torcular herophili (meningioma G2). After 3 years, a local recurrence requires GKRS combined with tamoxifen. In the next 7 years, she underwent 5 GKRS procedures for local recurrence. The patient also underwent chemotherapy with octreotide. At the age of 61, she discovered multiple lesions in both lungs, liver, and kidney. A hepatic biopsy showed anaplastic meningioma G3. Also this patient does not suffer from any neurologic or clinical deficits. CONCLUSIONS: LC in malignant meningioma is achievable through a multimodal approach; GKRS makes possible LC, but a novel aspect of these lesions is opened to discussion: the metastases. These reports show that multimodal treatment for MMs is an effective approach with good LC and improvement of overall survival. However, a long survival may allow systemic diffusion of the disease, in particular, when sagittal sinus is involved.

Cranioplasty with Porous Hydroxyapatite Custom-Made Bone Flap: Results from a Multicenter Study Enrolling 149 Patients Over 15 Years.

BACKGROUND: Despite the mixed evidence regarding the effect of decompressive craniectomy in terms of outcome, a tremendous increase in related reports has been observed in the last years. Cranioplasty plays a key role in restoring function and anatomy of the cranial vault. Considering that cranioplasty is not exempt from risks, the identification of the safest technique becomes crucial to achieve better patients' recovery. Porous hydroxyapatite (PHA) has received growing attention for its potential in bony integration. Here we report a multicenter prospective follow-up analysis of 149 patients who underwent cranioplasty with PHA prostheses. In particular, we focus on the incidence of adverse events and implant removal. METHOD: From January 2001 to December 2015 we conducted a prospective multicenter study of 149 patients who underwent cranioplasty with custom-made PHA flaps after decompressive craniectomy for several reasons. The endpoints were the incidence of adverse events after cranioplasty and of related implant removal. RESULTS: 66 patients (44%) were treated within 6 months from decompression, and only 2 patients had a bifrontal bilateral reconstruction. Of those, 25 patients reported complications (16.8%), and 9 of them (6% of the whole case series) required removal of the prosthesis. The only significant factor predicting cranioplasty removal was a previous infection. CONCLUSION: Hydroxyapatite for cranial implants is fully comparable to other heterologous materials. It has a biologic potential of bony integration. The risk of explants seems to be significantly higher in second-line patients, data not shown in previous studies.

Comparison between the different types of heterologous materials used in cranioplasty: a systematic review of the literature.

INTRODUCTION: The choice of heterologous materials for cranioplasty after decompressive craniectomy is still difficult. The aim of this study is to examine the association between material of choice and related complications to suggest the best treatment option. EVIDENCE ACQUISITION: A systematic review was performed for articles reporting cranioplasty comparing the following heterologous implants: titanium, poli-methyl-methacrylate (PMMA), polyetheretherketone (PEEK) and hydroxyapatite (HA). Extracted data included implant materials and incidence of the most frequent complications. EVIDENCE SYNTHESIS: The final selection resulted in 106 papers but according to our rules only 27 studies were included in the final analysis. Among a total of 1688 custom-made prosthesis implanted, 649 were titanium (38.49%), 298 PMMA (17.56%), 233 PEEK (13.82%), and 508 were HA (30.13%). A total of 348 complications were recorded out of 1688 reported patients (20.64%). In the titanium group, 139 complications were recorded (21.42%); in the PMMA group 57 (19.26%), in the PEEK group 49 (21.03%) and in the HA group 103 (20.3%). If we examine a summary of the reported complications clearly related to cranioplasty (postoperative infections, fractures and prosthesis displacement) versus type of material in multicentric and prospective studies we can see how HA group patients have less reported infections and cranioplasty explantation after infections than PMMA, PEEK and titanium. On the contrary HA patients seem to have a higher number of prosthesis displacement again if compared with the other materials. Since these data are not derived from a statistically correct analysis they should be used only to help to differentiate the properties of the various heterologous cranioplasties. CONCLUSIONS: The ideal material for all heterologous cranioplasty has not yet been identified. The choice of material should be based on the clinical data of patients, such as the craniectomy size, presence of seizures, possibility of recovery, good long-term outcome associated with a cost analysis.