Robot-assisted sacral tumor resection: a preliminary study

Rare retroperitoneal giant sacral schwannoma: A case report

Schwannomas localized in the sacrum are relatively infrequent, accounting for 1-5% of all spinal axis schwannomas; they present with vague symptoms or are symptomless, so often grow to a considerable size before detection. Sacral schwannomas occasionally present with enormous dimensions, and these tumors are termed giant sacral schwannomas. However, their surgical removal is challenging owing to an abundant vascularity. The present study retrospectively analyzed the clinical and follow-up data of a patient with a giant sacral schwannoma. The patient experienced numbness in the left buttock and lower extremity, with radiating pain in the sole of the foot that had persisted for 3 years. A presacral mass was found by computed tomography examination 6 months after the stool had become thin. A tumor resection was performed using the anterior abdominal approach. A schwannoma was diagnosed by postoperative pathology. The postoperative course was uneventful, with the complete resolution of symptoms during the 21-month clinical follow-up. Overall, the present study reports the case of a giant sacral schwannoma with pelvic pain that was resected without complications and also discusses its successful management. Additionally, the study presents a systematic review of the literature. We consider that the surgical treatment of giant sacral schwannomas with piecemeal subtotal excision can achieve good outcomes, avoiding unnecessary neurological deficits.

Presacral tumors: A systematic review of literature

Presacral/Retrorectal tumors (RRT) are rare lesions that comprise a multitude of histological types. Data on surgical management are limited to case reports and small case series. The aim of the study was to provide a comprehensive review of the epidemiology, pathological subtypes, surgical approaches, and clinical outcomes. A PubMed search using terms "retrorectal tumor" and "presacral tumor" was used to identify articles reporting RRT of non-urological, non-gynecologic, and non-metastatic origin. Articles included were between 2015 and 2023. A total of 68 studies were included, comprising 570 patients. About 68.2% of patients were female, and the mean overall age of both sexes was 48.6 years. Based on histopathology, 466 patients (81.8%) had benign lesions, and 104 (18.2%) were malignant. In terms of surgical approach, 191 (33.5%) were treated anteriorly, 240 (42.1%) through a posterior approach, and 66 (11.6%) combined. The mean length of stay was 7.6 days. Patients treated using the posterior approach had a shorter length of stay (5.7 days) compared to the anterior and combined approaches. RRT are rare tumors of congenital nature with prevalence among the female sex. R0 resection is crucial in its management, and minimal access surgery appears to be a safer option in appropriate case selection.

The role of minimally invasive surgery within a multidisciplinary approach for patients with metastatic spine disease over a decade: A systematic review

BACKGROUND

Metastatic spine disease (MSD) occurs commonly in cancer patients causing pain, spinal instability, devastating neurological compromise, and decreased quality of life. Oncological patients are often medically complex and frail, precluding them form invasive procedures. To address this issue, minimally invasive spinal surgery (MISS) techniques are desirable. The aim of this study is to review published peer-reviewed literature and ongoing clinical trials to provide current state of the art.

METHODS

A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, assessing MISS in MSD patients for the period 2013-2023. Innovations under development were assessed by querying and reviewing data from currently enrolling U.S. registered clinical trials.

RESULTS

From 3,696 articles, 50 studies on 3,196 patients focused on spinal oncology MISS. The most commonly reported techniques were vertebral augmentation (VA), percutaneous spinal instrumentation, and radiofrequency ablation (RFA). Surgical instrumentation/stabilization techniques were reported in 10/50 articles for a total of 410 patients. The majority of studies focused on pain as a primary outcome measure, with 28/50 studies reporting a significant improvement in pain following intervention. In the United States, 13 therapeutic trials are currently recruiting MSD patients. Their main focus includes radiosurgery, VA and/or RFA, and laser interstitial thermal therapy.

CONCLUSIONS

Due to their medical complexity and increased fragility, MSD patients may benefit from minimally invasive approaches. These strategies are effective at mitigating pain and preventing neurological deterioration, while providing other advantages including ease to start/resume systemic/radiotherapy treatment(s).

Spine Surgical Robotics: Current Status and Recent Clinical Applications

With the development of artificial intelligence and the further deepening of medical-engineering integration, spine surgical robot-assisted (RA) technique has made significant progress and its applicability in clinical practice is constantly expanding in recent years. In this review, we have systematically summarized the majority of literature related to spine surgical robots in the past decade, and not only classified robots accordingly, but also summarized the latest research progress in RA technique for screw placement such as cervical, thoracic, and lumbar pedicle screws, cortical bone trajectory screws, cervical lateral mass screws, and S2 sacroiliac screws; guiding targeted puncture and placement of endoscope via the intervertebral foramen; complete resection of spinal tumor tissue; and decompressive laminectomy. In addition, this report also provides a detailed evaluation of RA technique's advantages and disadvantages, and clarifies the accuracy, safety, and practicality of RA technique. We consider that this review can help clinical physicians further understand and familiarize the current clinical application status of spine surgical robots, thereby promoting the continuous improvement and popularization of RA technique, and ultimately benefiting numerous patients.

Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection

BACKGROUND

Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection.

OBJECTIVE

To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery.

METHODS

Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm.

RESULTS

Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted.

CONCLUSION

With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

Surgical management of sacral schwannomas: a 21-year mayo clinic experience and comparative literature analysis

INTRODUCTION

Sacral and presacral schwannomas are rare, accounting for a minority of spinal schwannomas. We present our institution's experience surgically treating spinal schwannomas and compare it to the literature.

METHODS

Data were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and 93 patients in the literature. Kaplan-Meier disease-free survival analysis was conducted. Unpaired two-sample t tests and Fisher's exact tests assessed statistical significance between groups.

RESULTS

Our patients and those in the literature experienced a similar age at diagnosis (49.9 y/o. vs 43.4 y/o., respectively). Most of our patients (59.3%) reported full recovery from symptoms, while a minority reported partial recovery (33.3%) and no recovery (11.1%). A smaller percentage in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%). Disease-free survival curves for all patients showed no significant variation in progression by extent of resection of schwannoma (log-rank P = 0.26). No lesion progression was associated with full or partial symptom improvement (p = 0.044), and female patients were more likely to undergo resection via a posterior approach (p = 0.042).

CONCLUSION

Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

Tumor retrorrectal: Reporte de un caso de Schwannoma

Introducción. En el espacio retrorrectal o presacro pueden desarrollarse lesiones tumorales, tanto benignas como malignas. La mayoría de los pacientes son asintomáticos y, cuando presentan síntomas, éstos son inespecíficos. Entre los tumores retrorrectales se destaca el grupo de origen neurogénico, donde el Schwannoma es el más frecuente. Caso clínico. Mujer de 32 años, con tumor retrorrectal, que producía una sintomatología escasa e imprecisa, diagnosticado durante una intervención quirúrgica por mioma uterino, que finalmente resultó ser un Schawnnoma. Conclusión. La tomografía computarizada y la resonancia magnética son importantes para el diagnóstico y para establecer el nivel de la lesión en relación con el sacro. La piedra angular del tratamiento es la resección quirúrgica. El abordaje puede ser anterior (abdominal), posterior (perineal, transsacro o parasacrococígeo) o combinado, de acuerdo con su localización al nivel S4.

Robotic Nerve Sheath Tumor Resection With Intraoperative Neuromonitoring: Case Series and Systematic Review

BACKGROUND

Retroperitoneal nerve sheath tumors present a surgical challenge. Despite potential advantages, robotic surgery for these tumors has been limited. Identifying and sparing functional nerve fascicles during resection can be difficult, increasing the risk of neurological morbidity.

OBJECTIVE

To review the literature regarding robotic resection of retroperitoneal nerve sheath tumors and retrospectively analyze our experience with robotic resection of these tumors using a manual electromyographic probe to identify and preserve functional nerve fascicles.

METHODS

We retrospectively analyzed the clinical courses of 3 patients with retroperitoneal tumors treated at the National Institutes of Health by a multidisciplinary team using the da Vinci Xi system. Parent motor nerve fascicles were identified intraoperatively with a bipolar neurostimulation probe inserted through a manual port, permitting tumor resection with motor fascicle preservation.

RESULTS

Two patients with neurofibromatosis type 1 underwent surgery for retroperitoneal neurofibromas located within the iliopsoas muscle, and 1 patient underwent surgery for a pelvic sporadic schwannoma. All tumors were successfully resected, with no complications or postoperative neurological deficits. Preoperative symptoms were improved or resolved in all patients.

CONCLUSION

Resection of retroperitoneal nerve sheath tumors confers an excellent prognosis, although their deep location and proximity to vital structures present unique challenges. Robotic surgery with intraoperative neurostimulation mapping is safe and effective for marginal resection of histologically benign or atypical retroperitoneal nerve sheath tumors, providing excellent visibility, increased dexterity and precision, and reduced risk of neurological morbidity.

Management of chordoma of the sacrum and mobile spine

Chordoma is a very rare, poorly known malignancy, with slow progression, mainly located in the sacrum and spine. All age groups may be affected, with a diagnostic peak in the 5th decade of life. Clinical diagnosis is often late. Histologic diagnosis is necessary, based on percutaneous biopsy. Specific markers enable diagnosis and prediction of response to novel treatments. New radiation therapy techniques can stabilize the tumor for 5 years in inoperable patients, but en-bloc resection is the most effective treatment, and should be decided on after a multidisciplinary oncology team meeting in an expert reference center. The type of resection is determined by fine analysis of invasion. According to the level of resection, the patients should be informed and prepared for the expected vesico-genito-sphincteral neurologic sequelae. In tumors not extending above S3, isolated posterior resection is possible. Above S3, a double approach is needed. Anterior release of the sacrum is performed laparoscopically or by robot; resection uses a posterior approach. Posterior wall reconstruction is performed, with an associated flap. Spinopelvic stabilization is necessary in trans-S1 resection. Total or partial sacrectomy shows high rates of complications: intraoperative blood loss, infection or mechanical issues. Neurologic sequelae depend on the level of root sacrifice. No genital-sphincteral function survives S3 root sacrifice. Patient survival depends on initial resection quality and the center's experience. Immunotherapy is an ongoing line of research.

Robot-assisted ventral sacral Tarlov cystectomy; A case report

Introduction and importance

Although asymptomatic Tarlov cysts (TCs) are reported in up to 13% of the population, symptomatic TCs are rare (less than 1%), making the management of the symptomatic cysts controversial. The most common location of symptomatic TCs is sacral nerve roots where they can cause pelvic, perineal chronic discomfort and pain, and lower extremity sensory and motor changes. Ventral (intrapelvic retroperitoneal) sacral TCs are extremely rare with no management recommendations. Available surgical options include cyst resection, and inlet-obliteration, however, these methods are often considered invasive and not definitive.

Case presentation

A 39-year-old woman presented with debilitating low back pain (LBP) radiating to her pelvis and the right lower extremity for 4 years. Magnetic Resonance Imaging (MRI) showed multiple sacral nerve root TCs including a large retroperitoneal right S3 TC. Surgical resection of the right S3 cyst was achieved utilizing a robot-assisted anterior approach which provided excellent visualization and maneuverability in the targeted retroperitoneal space. Postoperatively, the patient experienced significant pain relief, and she was able to perform activities of daily life and return to work.

Clinical discussion

Robotic-assisted pelvic surgery has gained widespread popularity in the last two decades due to its many potential benefits. Utilizing robotic systems in sacral nerve sheath lesions shows a promise to deliver effective minimally invasive surgical management without sacrificing good visualization or instrument maneuverability.

Conclusion

Robot-assisted resection of sacral nerve roots TCs represents a minimally invasive and safe surgical option to manage cysts located anterior to the sacrum in the pelvic retroperitoneal space.

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Tarlov cysts are incidental findings that often affect the sacral nerve roots.

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We present a rare case of a sacral root Tarlov cyst with large pelvic extension.

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Management of such cases can be elusive, due to the cyst location.

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Robot-assisted cystectomy surgery achieved a successful resection and pain relief.

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This report endorses such minimally invasive techniques to reach sacral roots.

Partial sacrectomy with patient-specific osteotomy guides

Background

Chordomas are rare, locally aggressive, malignant tumors. Surgical resection with sufficient margins defines the outcome. However, the necessity for wide margins often leads to sacrifice of important neurological structures. 3D-printed osteotomy guides are a promising solution for precise execution of surgical resection. We present probably the first sacrococcygeal chordoma resection with 3D-printed guides.

Methods

The case of a 49-year-old woman with a sacrococcygeal chordoma, resected with help of 3-D pre-operative planning and patient-specific 3D-printed osteotomy guides, is reported in detail.

Results

A sufficient tumor excision could be performed successfully while sparing nerve root S4. The planed margin has been exactly maintained, as confirmed by histology. The patient demonstrated an excellent clinical outcome with no evidence of local recurrence.

Conclusions

3-D pre-operative planning and patient-specific osteotomy guides can be used for planning and performing en-bloc surgical resection of sacral chordomas.

The Surgical Approach Combined With Minimally Invasive Surgery for Sacral Chordoma

Sacral chordomas are malignant, locally aggressive, and rare tumors. Its presentation can be diverse on the entire spine, being more frequent in the sacrococcygeal region. The main treatment is complete surgical resection, which can be performed using different approaches depending on the case. We present the case of a 44-year-old woman with a history of a complex adnexal mass, with an imaging finding of a presacral mass displacing the uterus and rectum, with a histological report of an image-guided biopsy suggestive of a soft-tissue myoepithelioma-like tumor, which was managed with a combined approach: anterior transabdominal laparoscopic and posterior approach, achieving complete tumor resection, without postoperative complications and with the benefits of minimally invasive surgery. The pathology report of the surgical piece was compatible with sacral chordoma.

Radiotherapy and Surgical Advances in the Treatment of Metastatic Spine Tumors: A Narrative Review

Spine tumors encompass a wide range of diseases with a commensurately broad spectrum of available treatments, ranging from radiation for spinal metastases to highly invasive en bloc resection for primary vertebral column malignancies. This high variability in treatment approaches stems both from variability in the goals of surgery (e.g., oncologic cure vs. symptom palliation) and from the significant advancements in surgical technologies that have been made over the past 2 decades. Among these advancements are improvements in surgical technique, namely minimally invasive approaches, increased availability of focused radiation modalities (e.g., proton therapy and linear accelerator devices), and new surgical technologies, such as carbon fiber-reinforced polyether ether ketone rods. In addition, several groups have described nonsurgical interventions, such as vertebroplasty and kyphoplasty for spinal instability secondary to pathologic fracture, and lesion ablation with spinal laser interstitial thermoablation, radiofrequency ablation, or cryoablation. We provide an overview of the latest technological advancements in spinal oncology and their potential usefulness for modern spinal oncologists.

Minimally Invasive Surgery Strategies: Changing the Treatment of Spine Tumors

Innovation in surgical technique and contemporary spinal instrumentation paired with intraoperative navigation/imaging concepts allows for safer and less-invasive surgical approaches. The combination of stereotactic body radiotherapy, contemporary surgical adjuncts, and less-invasive techniques serves to minimize blood loss, soft tissue injury, and length of hospital stay without compromising surgical efficacy, potentially enabling patients to begin adjuvant treatment sooner.

Application of the da Vinci surgical robot system in presacral nerve sheath tumor treatment

The aim of the present study was to investigate the feasibility of da Vinci robotic surgery in the treatment of presacral tumors, and to observe its efficacy and safety. Between March 2016 and April 2019, 12 patients with presacral nerve sheath tumors underwent da Vinci robotic surgery, and the integrity of the tumor resection, surgical duration, pre- and postoperative visual analog scale (VAS) score, intra- and postoperative blood losses, postoperative bedtime, hospital stay and complications were observed. The tumor was completely removed in all 12 patients, the surgical duration ranged between 76 and 245 min (mean, 106.08 min) and the intraoperative blood loss was 76-145 ml (mean, 101.67 ml). The average preoperative VAS score of the patients was 3.25, and the average VAS score at 1 week, 1 month and 3 months post operation were 1.08, 0.42 and 0.08, respectively. All patients were out of bed on the second day after surgery, and the postoperative drainage was 10-50 ml (mean, 33.50 ml). The patients were hospitalized for 3-5 days (mean, 3.92 days). No complications occurred peri- or postoperatively, and wound pain was the main source of postoperative discomfort. In conclusion, the da Vinci robot can be applied to presacral nerve sheath tumors with high surgical safety, low-level bleeding, a rapid recovery and a short hospital stay, making it worthy of further study.

A Combined One-Staged Robot-Assisted Sacral Chordoma Resection

BACKGROUND

The robotic surgery is an advanced modern minimally invasive technology, widely used in urologic oncology, and it has become useful in particular conditions. Over time, different surgical specialties made use of the robotic properties to minimize complications for high-risk procedures. A combined 1-staged robot-assisted multidisciplinary surgery with intraoperative neurophysiological monitoring can be a safe procedure to remove a sacral chordoma with low morbidity rates.

CASE DESCRIPTION

A 64-year-old woman complained of a few months of drug-resistant low back and abdominal pain. The subsequent development of constipation brought the patient to undergo an abdominal computed tomography scan and magnetic resonance imaging. Radiologic investigations revealed a large size sacral mass associated with a partial destruction of the sacrum and posterior compression of the rectum. The tumor was en bloc removed by a combined 1-staged anterior laparoscopic robot-assisted and posterior open lumbosacral approach with continue intraoperative neurophysiological monitoring of sacral and pudendal plexuses. The histological diagnosis was of chordoma. After surgery, the patient reported pain relief and the total recovery of bowel dysfunction with good 11-month follow-up outcome.

CONCLUSIONS

This combined technique represents a promising treatment option in selected cases. The robotic technology combined with the experience of highly qualified staff can improve the surgical result by minimizing complications. However, longer follow-up is necessary to confirm the long-term effects in terms of recurrence and survival.

Management of presacral schwannomas-a 10-year multi-institutional series

Presacral or sacral schwannomas are relatively rare clinical entities thought to account for only 1 in every 40,000 hospitalizations. These lesions are benign, frequently monofocal, and arise from the exiting sacral nerve roots. Lesions are often asymptomatic, but may present with bulk symptoms (constipation, urinary frequency), sciatica, lower extremity weakness, and para-axial lumbosacral pain. At present, the treatment of choice for these lesions is gross total resection, with an approach dictated by the size of the intrasacral component. Despite numerous isolated case reports, few case series exist. Of those extant series, none are multi-institutional and only a handful describe multiple alternative approaches for the treatment of these tumors. Here we describe a series of seven patients treated at two tertiary care centers for sacral schwannoma with post-operative follow-up as far as 6 years.

Surgical management of giant presacral schwannoma: systematic review of published cases and meta-analysis

OBJECTIVE

Giant presacral schwannomas are rare sacral tumors found in less than 1 of every 40,000 hospitalizations. Current management of these tumors is based solely upon case reports and small case series. In this paper the authors report the results of a systematic review of the available English literature on presacral schwannoma, focused on identifying the influence of tumor size, tumor morphology, surgical approach, and extent of resection (EOR) on recurrence-free survival and postoperative complications.

METHODS

The medical literature (PubMed and EMBASE) was queried for reports of surgically managed sacral schwannoma, either involving 2 or more contiguous vertebral levels or with a diameter ≥ 5 cm. Tumor size and morphology, surgical approach, EOR, intraoperative and postoperative complications, and survival data were recorded.

RESULTS

Seventy-six articles were included, covering 123 unique patients (mean age 44.1 ± 1.4 years, 50.4% male). The most common presenting symptoms were leg pain (28.7%), lower back pain (21.3%), and constipation (15.7%). Most surgeries used an open anterior-only (40.0%) or posterior-only (30%) approach. Postoperative complications occurred in 25.6% of patients and local recurrence was noted in 5.4%. En bloc resection significantly improved progression-free survival relative to subtotal resection (p = 0.03). No difference existed between en bloc and gross-total resection (GTR; p = 0.25) or among the surgical approaches (p = 0.66). Postoperative complications were more common following anterior versus posterior approaches (p = 0.04). Surgical blood loss was significantly correlated with operative duration and tumor volume on multiple linear regression (both p < 0.001).

CONCLUSIONS

Presacral schwannoma can reasonably be treated with either en bloc or piecemeal GTR. The approach should be dictated by lesion morphology, and recurrence is infrequent. Anterior approaches may increase the risk of postoperative complications.

Computed Tomography-Guided Posterolateral Transsacral Ala Approach to Presacral L5 Schwannoma: Technical Note

BACKGROUND

Presacral schwannomas are rare benign tumors that may reach large size before becoming symptomatic. Total surgical removal has been considered the best treatment option. Tumors arising from the presacral area are commonly managed through anterior approaches, whereas posterior approaches are used for pure intrasacral tumors or large lesions with both intrasacral and presacral extension, alone or in combination with anterior approaches.

METHODS

We describe a quick and minimally invasive navigation-guided posterolateral approach to a right presacral L5 schwannoma. The lesion was microsurgically removed through high-speed drilling of the upper portion of the right sacral ala, under intraoperative neurophysiologic monitoring.

RESULTS

The postoperative course was unremarkable, and the patient experienced improvement in his sensory disturbance. Postoperative magnetic resonance imaging and computed tomography scan showed the complete excision of the lesion and the removal of the upper sacral ala with preservation of the right L5-S1 articular complex. The histologic examination confirmed a schwannoma (World Health Organization grade I).

CONCLUSIONS

The posterolateral transsacral ala approach may represent a minimally invasive option in the surgical management of presacral well-circumscribed benign tumors. Spinal navigation could be properly used to facilitate lesion exposure and to minimize the bone removal. The intraoperative neurophysiologic monitoring is an essential tool for the preservation of the lumbosacral nerve roots.

The extended posterior approach for resection of sacral tumours

PURPOSE

The conventional posterior approach is mostly advocated for excision of sacral tumours below S2. We describe an operative technique of single-stage en bloc resection of sacral tumours, extending up to S1, through an extended posterior approach.

METHOD

Nine patients, who had undergone resection of sacral tumours, by the described technique formed the basis of this study. Four patients had chordomas, whereas schwannoma, neurilemmoma, giant-cell tumour, malignant paraganglioma and recurrent Ewing's sarcoma were seen in one patient each. They were followed up at regular intervals with a mean follow-up of 45.4 months. Perioperative complications, their functional and oncological outcomes at final follow-up were analysed.

RESULT

None of the patients had any perioperative complications like uncontrolled haemorrhage, injury to the rectum, deep vein thrombosis or pulmonary embolism. One patient had a superficial wound infection which subsided with regular dressing, and another patient developed a wound breakdown that required an additional flap procedure. At final follow-up, six patients were able to walk without any assistive devices, six patients had normal bladder function, and five patients had normal bowel function. Five patients did not have any recurrence at final follow-up, whereas two were alive with the disease and two had died.

CONCLUSION

The reported technique allows en bloc resection of sacral tumours up to S1, through a posterior-only approach. It is less invasive with minimal morbidity. The functional and oncological outcomes are similar to those reported by other investigators. These slides can be retrieved from electronic supplementary material.