Minimally Invasive Approaches to Vertebral Column and Spinal Cord Tumors

First Experience Using a New Minimally Invasive Screw-Rod System for Completely Percutaneous Pedicle Screw Fixation of the Cervical Spine

In contrast to the thoracolumbar spine, where pedicle screws can be inserted via a minimally invasive, percutaneous technique through small skin incisions, all previously available cervical instrumentation systems required a larger midline incision, especially for rod insertion. Screw placement via small incisions reduces the risk of wound healing disorders and blood loss, and patients can be mobilized more quickly and with less pain. In 2022, a cervical, minimally invasive stabilization system became available for the complete percutaneous insertion of both cervical pedicle screws and rods. We report on the first results and experiences with this new technology.In this retrospective case series, we included patients with cervical instability treated by minimally invasive percutaneous cervical and upper thoracic spine pedicle screw and rod insertion between August 2022 and August 2023. Intra- and postoperative complications as well as revision surgeries were recorded. The screw position was evaluated by three examiners in the postoperative computed tomography (CT) using the Bredow classification.Our series includes six male patients (age = 56.9 ± 12.9 years; body mass index [BMI] = 29.8 ± 9.6 kg/m2). The indication for surgery was trauma, tumor, and degenerative stenosis in two patients each. An excellent/good screw position (Bredow 1 and 2) was found in 84.4% of the screws (n = 27/32). None of the screws rated as Bredow 3 (n = 2/32) or Bredow 4 (n = 3/32) resulted in a neurological deficit or radicular pain and none had to be repositioned. No neurologic complication or revision surgery occurred. As a complication not directly related to the surgery technique, one patient died of a pulmonary lung embolism on the seventh postoperative day.The results of this study indicate that minimally invasive percutaneous implantation of a pedicle screw-rod system is also possible in the cervical spine with sufficient accuracy using intraoperative navigation. However, technical details, possible pitfalls and finally careful patient selection must be taken into account.

Minimally Invasive Lateral Retroperitoneal Approach for Resection of Extraforaminal Lumbar Schwannomas: Results After 1-Year Follow-Up

OBJECTIVE

Extradural spinal nerve sheath tumors with foraminal involvement are rare, and the gold standard for surgical resection is not established yet. Traditionally, lumbar intra-extraforaminal schwannomas have been resected through a posterior midline or paraspinal open approach. The lateral transpsoas approach represents a suitable, minimally invasive approach which can provide direct access to the extraforaminal and lumbar plexus region avoiding bone removal, hence the necessity of lumbar fusion. The aim of this study is to share our experience of extraforaminal lumbar schwannomas approached through a minimally invasive lateral transpsoas technique with intraoperative neurophysiological monitoring.

METHODS

This is a single-center retrospective case series study. Seven adult patients who underwent extraforaminal lumbar schwannoma removal through a lateral retroperitoneal approach were enrolled. A detailed description of the surgical technique is reported. The outcome measures included mean surgical duration, mean blood loss, postoperative mobilization, day of discharge, complication, postoperative symptoms, and extent of removal. All patients had a minimum follow-up of 1 year.

RESULTS

The average age was 51 years. Surgery lasted 225 minutes on average, with minimal blood loss. One patient had a cerebrospinal fluid leak, which was successfully repaired. Most patients were mobilized the day after surgery and 6 were discharged within 2-4 days. At a 12-month follow-up, 6 patients showed symptom improvement and magnetic resonance imagings confirmed complete tumor resection in all cases.

CONCLUSIONS

Retroperitoneal transpsoas approach represents a safe tool in the neurosurgeon's armamentarium, particularly suitable for this subset of tumors representing a short and direct way to approach them. Surgeon confidence of working inside the psoas and close to the lumbar plexus is increased using continuous electromyography monitoring. At the end, the retroperitoneal transpsoas approach for extraforaminal lumbar schwannoma can provide minimal soft tissue damage, better pain control, decreased blood loss, and short hospitalization.

A cadaveric precision and accuracy analysis of augmented reality-mediated percutaneous pedicle implant insertion

OBJECTIVE

Augmented reality-mediated spine surgery (ARMSS) is a minimally invasive novel technology that has the potential to increase the efficiency, accuracy, and safety of conventional percutaneous pedicle screw insertion methods. Visual 3D spinal anatomical and 2D navigation images are directly projected onto the operator's retina and superimposed over the surgical field, eliminating field of vision and attention shift to a remote display. The objective of this cadaveric study was to assess the accuracy and precision of percutaneous ARMSS pedicle implant insertion.

METHODS

Instrumentation was placed in 5 cadaveric torsos via ARMSS with the xvision augmented reality head-mounted display (AR-HMD) platform at levels ranging from T5 to S1 for a total of 113 total implants (93 pedicle screws and 20 Jamshidi needles). Postprocedural CT scans were graded by two independent neuroradiologists using the Gertzbein-Robbins scale (grades A-E) for clinical accuracy. Technical precision was calculated using superimposition analysis employing the Medical Image Interaction Toolkit to yield angular trajectory (°) and linear screw tip (mm) deviation from the virtual pedicle screw position compared with the actual pedicle screw position on postprocedural CT imaging.

RESULTS

The overall implant insertion clinical accuracy achieved was 99.1%. Lumbosacral and thoracic clinical accuracies were 100% and 98.2%, respectively. Specifically, among all implants inserted, 112 were noted to be Gertzbein-Robbins grade A or B (99.12%), with only 1 medial Gertzbein-Robbins grade C breach (> 2-mm pedicle breach) in a thoracic pedicle at T9. Precision analysis of the inserted pedicle screws yielded a mean screw tip linear deviation of 1.98 mm (99% CI 1.74-2.22 mm) and a mean angular error of 1.29° (99% CI 1.11°-1.46°) from the projected trajectory. These data compare favorably with data from existing navigation platforms and regulatory precision requirements mandating that linear and angular deviation be less than 3 mm (p < 0.01) and 3° (p < 0.01), respectively.

CONCLUSIONS

Percutaneous ARMSS pedicle implant insertion is a technically feasible, accurate, and highly precise method.

Direct Lateral Minimally Invasive Approach for Excision of a L1/L2 Neurofibroma-A Technical Note and Literature Review

A case of resection of a large dumbbell-shaped nerve sheath tumor at L1/L2 via a direct lateral minimally invasive approach is described. The tumor was removed via a lateral, subdiaphragmatic, rib-sparing, retropleural, retroperitoneal approach. The thoracolumbar junction can be challenging via the lateral approach and to the best of our knowledge this is the first report of excision of a paravertebral tumor via this approach. We believe this provided the benefits of direct operative trajectory and exposure, excellent tumor access, and avoided the need for facetectomy and extended spinal instrumentation across the thoracolumbar junction. Complete tumor excision was achieved with preserved motor function and improvement in radicular pain and sensory neurological deficit.

Risk factors predicting less favorable outcomes in endoscopic lumbar discectomies

Background

Endoscopic lumbar discectomy was among the first minimally invasive spine procedures commonly performed. As such, all the benefits of minimal invasion were seen, including less pain, less soft tissue destruction, and faster recovery. While outcomes compare favorably to micro and open discectomy, not all patients fare equally well. This paper examines independent risk factors to assess their correlation to suboptimal outcomes after endoscopic lumbar discectomy.

Methods

Retrospective analysis of clinical outcomes of 55 consecutive patients treated with endoscopic discectomy between June 2018 and March 2019 by the author. Primary outcome measures were postoperative reductions of visual analog score (VAS) for back and leg pain modified MacNab criteria as well as time to narcotic independence. Risk factors examined included smoking, facet disease, adjacent segments disc degeneration, obesity, alcohol abuse, and psychiatric illness.

Results

There were 31 males and 24 females with a mean age of 41.76±12.53. Most patients suffered from contained herniations (49.1%) followed by extruded herniations (18.2%). Follow-up ranged from 6-18 months. The most common surgical levels were L5-S1 level (30.9%), L4-S1 (29.1%), and L4-5 (25.5%). The mean return to work (RTW) was 23.83±26.01 weeks. The average body mass index (BMI) was 29.11±4.75. The average time for narcotic independence was 9.64±7.29 days. MacNab outcomes showed that 47.3% (26/55) had excellent, 36.4% good (20/55), 12.7% fair (7/55), and 3.6% had poor (2/55), respectively. The VAS scores for the back (7.69 to 2.65) and leg (6.78 to 2.65) pain reduced significantly (P<0.0001). Smoking (P=0.048), psychiatric disease (P=0.029), disc herniations larger than 10 mm, facet disease, obesity (BMI >30), diabetes, and alcohol abuse was associated with fair and poor MacNab outcomes.

Conclusions

Endoscopic lumbar discectomy safely and reliably reduces axial pain and radiculopathy from lumbar disc herniations. Risk factors associated with incomplete pain relief are large herniations, obesity, instability, smoking, advanced facet degeneration, and decreased ability to cope with the surgery.

Minimally Invasive Lateral Retroperitoneal Approach for Resection of Extraforaminal Lumbar Plexus Schwannomas: Operative Techniques and Literature Review

BACKGROUND

Traditional approaches for retroperitoneal lumbar plexus schwannomas involve anterior open or laparoscopic resection. For select tumors, the lateral retroperitoneal approach provides a minimally invasive alternative.

OBJECTIVE

To describe a minimally invasive lateral transpsoas approach for the resection of retroperitoneal schwannomas.

METHODS

A lateral retroperitoneal transpsoas approach was used to resect a 3.1 × 2.7 × 4.1 cm schwannoma embedded within the psoas muscle. A minimally invasive retractor system allows for appropriate visualization and complete resection with the aid of the microscope. The patient tolerated the procedure without complication and was discharged on postoperative day 2 in good condition at her neurological baseline.

RESULTS

The lateral retroperitoneal approach provides a minimally invasive alternative for select retroperitoneal schwannomas. In theory, this procedure allows for faster recovery and less blood loss compared to traditional open anterior approaches. For a subset of tumors, anterior laparoscopy may provide better access, but the lateral approach is well known to most neurosurgeons who perform lateral interbody fusions and can be easily tailored to extraforaminal tumor resection.

CONCLUSION

Retroperitoneal schwannomas pose a challenge due to their deep location. The lateral retroperitoneal approach provides a useful alternative for resection of a subset of retroperitoneal schwannomas.

The Difference in Surgical Site Infection Rates Between Open and Minimally Invasive Spine Surgery for Degenerative Lumbar Pathology: A Retrospective Single Center Experience of 1442 Cases

BACKGROUND

Surgical site infection (SSI) in spinal surgery contributes to significant morbidity and healthcare resource utilization. Few studies have directly compared the rate of minimally invasive surgery (MIS) SSI with open surgery.

OBJECTIVE

To investigate whether MIS techniques had a lower SSI rate in degenerative lumbar procedures as compared with traditional open techniques.

METHODS

A single-center, retrospective review of a prospectively collected database was queried from January 2013 to 2016 for adult patients who underwent lumbar decompression and/or instrumented fusion for which the surgical indication involved degenerative disease. The SSI rate was determined for all procedures as well as in the open and minimally invasive groups. Risk factors associated with SSI were also reviewed for each patient.

RESULTS

A total of 1442 lumbar spinal procedures were performed during this time period. Of these, there were 961 MIS and 481 open (67% vs 33%, respectively). The overall SSI rate was 1.5% (21/1442). The surgical site infection rate for MIS was less than open techniques (0.5% vs 3.3%; P = .0003). For decompression only, the infection rate for MIS and open was 0.4% vs 3.9% (P = .04), and for decompression with fusion it was 0.7% vs 2.6%, respectively (P = .68).

CONCLUSION

Our study demonstrates a significant 7-fold reduction in SSIs when comparing MIS with open surgery. This significance was also demonstrated with a 10-fold reduction for procedures involving decompression alone. Procedures that require fusion as well as decompression showed a trend towards a decreased infection rate that did not reach clinical significance.

Minimally Invasive Excision of Thoracic Arachnoid Web

OBJECTIVE

Arachnoid webs are rare intradural lesions that can cause direct spinal cord compression or alteration of the cerebrospinal fluid flow with syringomyelia. Surgery has been historically performed through wide-open laminectomies. The aim of this study is to prove the feasibility of minimally invasive techniques for the excision of arachnoid webs.

METHODS

A retrospective review of two cases of minimally invasive excision of thoracic arachnoid webs was performed. Surgery was undertaken through expandable tubular retractors.

RESULTS

Complete excision was achieved through the described approach, with minimal bony removal and soft tissue disruption. There were no intraoperative or perioperative complications. Both patients were mobilized early and discharged home within 24 hours after surgery. Postoperative imaging showed good re-expansion of the spinal cord, with no evidence of residual compression or tethering.

CONCLUSIONS

For symptomatic arachnoid webs, surgery remains the only definitive treatment. In expert hands, the excision of arachnoid webs can be achieved with tubular retractors and minimally invasive techniques.

Minimally invasive "separation surgery" plus adjuvant stereotactic radiotherapy in the management of spinal epidural metastases

Aim:

This study aimed to describe the application of minimally invasive surgery (MIS) in separation surgery combined with postoperative stereotactic body radiation therapy (SBRT) in patients with symptomatic metastatic epidural spinal disease.

Methods:

Three techniques are described: (1) MIS posterior separation surgery alone, (2) MIS posterolateral separation surgery with percutaneous pedicle screw placement, and (3) MIS lateral corpectomy with percutaneous pedicle screw placement. Seven representative cases are presented in which the above techniques were applied and after which postoperative SBRT was performed.

Results:

The seven representative patients (3 male, 4 female) had a mean age of 54 years (range, 46–62 years). Two patients had a primary diagnosis of cholangiocarcinoma and in one patient each a diagnosis of breast, renal, lung adenocarcinoma, melanoma, and urothelial squamous cell carcinoma as their primary tumor. All patients had additional multiorgan disease apart from the metastatic spine involvement. Three patients underwent operations in the lumbar spine, two in the thoracic spine, and one in each of the thoraco-lumbar and lumbo-sacral spine. The average operating time was 149 ± 60.3 min (range, 90–240 min). The mean estimated blood loss was 188.8 cc. The mean length of stay in the hospital was 4 days (range, 3–7 days). There were no surgical complications. All patients received postoperative SBRT (typically 24 Gy in 3 fractions) at a mean of 43.2 days after surgery (range, 30–83).

Conclusions:

Early reports such as this suggest that MIS techniques can be successfully and safely applied in accomplishing “separation surgery” with adjuvant SBRT in the management of metastatic spinal disease. The potential advantages conferred by MIS techniques such as shortened hospital stay, decreased blood loss, reduced perioperative complications, and earlier initiation of adjuvant radiation are highly desirable in the treatment of this challenging patient population.

Minimally Invasive Direct Lateral Transpsoas Approach for the Resection of a Lumbar Plexus Schwannoma: Technique Report

Objective  Traditional techniques for resection of lumbar plexus tumors have been associated with approach-related morbidity. We describe a case utilizing a minimally invasive transpsoas lateral access approach to resect a retroperitoneal tumor of the lumbar plexus.

Methods  We report a case with an extradural retroperitoneal schwannoma of the L4 nerve root that was treated with a minimally invasive direct lateral transpsoas approach using atraumatic tissue dilators and an expandable tubular retractor. The use of directional and continuous electromyographic monitoring was critical in locating the plexus and positioning the retractor immediately anterior to the tumor.

Results  The patient tolerated the procedure well without postoperative complications. The operative approach was direct and intraoperative blood loss was negligible. The patient demonstrated improved left leg strength and ambulation and resolution of paresthesias.

Conclusions  A minimally invasive direct lateral transpsoas access approach is an effective technique to safely and adequately resect extradural retroperitoneal lumbar plexus tumors.

Perioperative Cost Analysis of Minimally Invasive vs Open Resection of Intradural Extramedullary Spinal Cord Tumors

BACKGROUND:

Minimally invasive spinal surgery (MIS) has emerged as a clinically effective tool but its cost-effectiveness remains unclear. No studies have compared MIS vs open surgical techniques for the treatment of intradural extramedullary (IDEM) tumors.

OBJECTIVE:

To analyze and compare open and MIS techniques for resection of IDEM tumors, with focus on perioperative costs.

METHODS:

Retrospective analysis of a prospectively collected database including 35 IDEM patients (18 open, 17 MIS). Perioperative data, hospital costs, and hospital and physician charges for in-hospital services associated with the index surgical procedure and readmissions within 90 days were compared.

RESULTS:

Mean estimated blood loss, operative time, preoperative hospital charges, and physician fees were similar between open and MIS techniques. Patient and tumor characteristics were similar between groups. MIS cases were associated with shorter intensive care unit and floor stay. There were 3 complications in the open group, requiring 2 readmissions and 1 reoperation. Hospital costs ($21 307.80 open, $15 015.20 MIS, P &lt; .01), and postoperative ($75 383.48 open, $56 006.88 MIS, P &lt; .01) and total charges ($100 779.38 open, $76 100.92 MIS, P &lt; .01) were significantly lower in the MIS group. There were no tumor recurrences in either group. All patients except for one in the open group maintained or improved their Nurick score.

CONCLUSION:

Both MIS and open techniques were able to adequately treat IDEM tumors. Reductions in complication rate and intensive care unit and hospital stay led to a decrease in hospital costs of almost 30% in the MIS group. MIS resection of IDEM tumors is not only an effective and safe option, but allows faster hospital discharge and significant cost savings.

Hemilaminectomy approach for intradural extramedullary spinal tumors: an analysis of 164 patients

OBJECT

The authors report their experience with the use of a minimally invasive hemilaminectomy approach for the excision of intradural extramedullary (IDEM) tumors of the spinal cord.

METHODS

Included were 164 consecutive patients (167 tumors in total), treated between January 2004 and December 2014, in whom the hemilaminectomy approach for IDEM spinal cord tumors was planned. The clinicoradiological data of patients presenting to Christian Medical College were analyzed retrospectively using a computerized chart-review method. Preoperative MRI localization was used in 51 cases.

RESULTS

The mean age (± SD) of the patients was 42.6 ± 16.6 years, and the mean duration of symptoms was 20.8 ± 27.8 months. The average tumor size was 2.4 ± 1.7 cm. Forty-four tumors were cervical, 5 were cervicothoracic, 72 were thoracic, 7 were thoracolumbar, and 39 were lumbar. Forty-two tumors were ventrally located, whereas 11 were ventrolateral; the rest were either dorsal or dorsolateral. The most common pathologies were schwannoma (110 cases) and meningioma (31 cases). Total excision was achieved for 93% of the tumors. The average duration of surgery was 1.6 ± 0.6 hours.

CONCLUSIONS

The hemilaminectomy approach to the removal of intradural tumors was quick and safe and resulted in minimal morbidity and no mortality. Preoperative MRI localization improved accuracy and reduced operating time by eliminating the need for intraoperative fluoroscopy.

Minimally Invasive Muscle Sparing Posterior-Only Approach for Lumbar Circumferential Decompression and Stabilization to Treat Spine Metastasis--Technical Report

OBJECTIVE

Palliative tumor resection and subsequent stabilization are important for maximizing function and quality of life for patients suffering from spinal metastases. However, traditional operative techniques for spinal metastases with vertebral body destruction involve extensive soft tissue dissection. In the lumbar spine, open 2-staged spine procedures are routinely required with an anterior retroperitoneal approach for corpectomy and cage insertion and posterior decompression and stabilization with pedicle screws and rods. Both stages require extensive soft tissue dissection that results in significant surgical morbidity, long recovery time, and subsequent delay in initiating postoperative chemoradiotherapy, as well as initially hampering patients' overall quality of life. A minimally invasive approach is desirable for achieving spinal stability, pain control, functional recovery, rapid initiation of adjuvant therapies, and overall patient satisfaction, especially in patients whose medical and surgical therapies are aimed at palliation rather than cure.

PRESENTATION

A 59-year-old man with renal cell carcinoma and a known L1 vertebral body metastasis presented with severe progressive low back pain and was found to have a pathologic L1 vertebral body fracture with focal kyphosis.

INTERVENTION

Here, we describe a minimally invasive muscle-sparing, posterior-only approach for L1 transpedicular hemicorpectomy and expandable cage placement, L1 laminectomy, and T11-L3 posterior instrumented stabilization. The surgical corridor was achieved through the Wiltse muscle plane between the multifidus and longissimus muscles so that minimal muscle detachment was required to achieve transpedicular access to the anterior and middle spinal columns. The L1 nerve root was completely skeletonized to allow adequate lumbar hemicorpectomy, tumor resection, and expandable titanium cage insertion. Lastly, percutaneous pedicle screws and rods were inserted from T11 to L3 for stabilization.

RESULT

The patient tolerated the procedure well with no complications and less than 200 mL estimated blood loss. Postoperative computed tomography revealed restoration of intervertebral height and adequate tumor resection with excellent placement of the expandable cage and posterior construct. The patient was discharged on postoperative day 4 and had nearly no back pain 3 weeks after surgery. Adjuvant therapies were started soon after. At the 6-month follow-up, the patient required minimal narcotic pain medication. Computed tomography scan demonstrated stable hardware with no evidence of failure.

CONCLUSION

A minimally invasive muscle-sparing, posterior-only approach is a promising surgical strategy for 360-degree decompression and stabilization for the treatment of lumbar spinal metastases with minimized blood loss, muscle detachment and postoperative pain, and fast postoperative recovery and initiation of adjuvant therapy.

Management of intended durotomy in minimally invasive intradural spine surgery

Object

Minimally invasive surgery (MIS) has been increasingly used for the treatment of various intradural spinal pathologies in recent years. Although MIS techniques allow for successful treatment of intradural pathology, primary dural closure in MIS can be technically challenging due to a limited surgical corridor through the tubular retractor system. The authors describe their experience with 23 consecutive patients from a single institution who underwent MIS for intradural pathologies, along with a review of pertinent literature.

Methods

A retrospective review of a prospectively collected surgical database was performed to identify patients who underwent MIS for intradural spinal pathologies between November 2006 and July 2013. Patient demographics, preoperative records, operative notes, and postoperative records were reviewed. Primary outcomes include operative duration, estimated blood loss, length of bed rest, length of hospital stay, and postoperative complications, which were recorded prospectively.

Results

Twenty-three patients who had undergone MIS for intradural spinal pathologies during the study period were identified. Fifteen patients (65.2%) were female and 8 (34.8%) were male. The mean age at surgery was 54.4 years (range 30–74 years). Surgical pathologies included neoplastic (17 patients), congenital (3 patients), vascular (2 patients), and degenerative (1 patient). The most common spinal region treated was lumbar (11 patients), followed by thoracic (9 patients), cervical (2 patients), and sacral (1 patient). The mean operative time was 161.1 minutes, and the mean estimated blood loss was 107.2 ml. All patients were allowed full activity less than 24 hours after surgery. The median length of stay was 78.2 hours. Primary sutured dural closure was achieved using specialized MIS instruments with adjuvant fibrin sealant in all cases. The rate of postoperative headache, nausea, vomiting, and diplopia was 0%. No case of cutaneous CSF fistula or symptomatic pseudomeningocele was identified at follow-up, and no patient required revision surgery.

Conclusions

Primary dural closure with early mobilization is an effective strategy with excellent clinical outcomes in the use of MIS techniques for intradural spinal pathology. Prolonged bed rest after successful primary dural closure appears unnecessary, and the need for watertight dural closure should not prevent the use of MIS techniques in this specific patient population.

Minimally invasive anterolateral corpectomy for spinal tumors

Traditional open anterior and posterior approaches for the thoracic and thoracolumbar spine are associated with approach-related morbidity and limited surgical access to the level of abnormality. This article describes the minimally invasive anterolateral corpectomy for the treatment of spinal tumors, and reviews the current literature.

Craniocervical junction diseases treatment with a minimally invasive approach

Objective: To introduce a new minimally invasive surgical approach to anterior and lateral craniocervical junction diseases, preserving the midline posterior cervical spine stabilizing elements and reducing the inherent morbidity risk associated with traditional approaches. Methods: We describe a novel surgical technique in four cases of extra-medullary anterolateral compressive lesions located in the occipito-cervical junction, including infections and intra- and/or extradural tumor lesions. We used a paramedian trasmuscular approach through an anatomical muscle corridor using a micro MaXcess(r) surgical expandable retractor, with the purpose of reducing morbidity and preserving the posterior muscle and ligamentous tension band. Results: This type of surgical approach provides adequate visualization and microsurgical resection of lesions and reduces muscle manipulation and devascularisation, preserving the tension of the ligament complex. There was minimal blood loss and a decrease in postoperative pain, with rapid start of rehabilitation and shorter hospitalization times. There were no intraoperative complications, and all patients recovered from their pre-operative symptoms. Conclusions: This novel surgical technique is feasible and adequate for the occipito-atlanto-axial complex, with better results than traditional procedures.

Minimally Invasive Posterior Trans-muscular C1-C2 Screw Fixation Through an Anatomical Corridor to Preserve Occipitocervical Tension Band: Surgical Anatomy and Clinical Experience

The C1-C2 joint is affected by multiple entities that may produce biomechanical instability. Optimal management for atlantoaxial instability has been searched by ways of different surgical techniques with different results, generating discussion between second effects of a particular treatment. Lateral dissections can place the axial neck musculature and ligaments at risk of neural denervations or vascular compromise. Either of these entities may result in significant postoperative atrophy, pain, and instability. Minimally invasive techniques for the treatment of spinal disorders allow to our patients less morbid procedures with equal or better results compared to conventional surgery. In the following paper, we review the anatomy of the atlantoaxial joint and propose a minimally invasive trans-muscular C1-C2 fusion technique using C1 lateral-mass screws and C2 pedicular screws. We describe cases with surgical, clinical, and radiographic follow-up.

Spinal cord compression

OPINION STATEMENT

Malignant epidural spinal cord compression (MESCC) remains a common neuro-oncologic emergency with high associated morbidity. Despite widespread availability of MRI, the diagnosis frequently goes unmade until myelopathy supervenes, which is unfortunate because the strongest predictor of neurologic outcome with treatment is the neurologic status when treatment is initiated. Once the diagnosis of MESCC is suspected, patients with neurologic deficits should be started on high-dose corticosteroids (eg, dexamethasone, 10-100 mg intravenously, followed by 16 to 100 mg/d in divided doses). Definitive therapy of MESCC almost always includes radiation therapy and in some cases surgical intervention; factors considered include the patient's performance status and extent of visceral and skeletal disease, spinal stability, the tumor's underlying radiosensitivity, and the degree of spinal cord compression. Patients with spinal instability or radioresistant tumors are likely to have a much better neurologic outcome with tumor resection and spinal stabilization prior to radiation; the same may also pertain to patients with moderately radiosensitive tumors who have good life expectancy in terms of their systemic tumor. Conventional radiation has historically been beneficial after surgery and in patients who are not surgical candidates. Recent studies suggest a role for stereotactic body radiation therapy in patients with spinal metastasis from radioresistant tumors and in patients who have received prior standard radiotherapy, so long as the spinal cord has been decompressed.

Natural orifice translumenal endoscopic surgery for anterior spinal procedures

Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae. Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique. Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily approached while avoiding damage to adjacent vessels. Bone biopsy was successfully performed without complications, but the hardness of bone tissue resulted in small and fragmented samples. Conclusions. Peroral transesophageal access into the posterior mediastinum and thoracic vertebral bone biopsy was feasible and safe. The proximity of the esophagus to the vertebral column provides close and direct access to the thoracic spine and opens up new ground for the performance of multilevel anterior spine procedures using NOTES techniques.

Less invasive approaches for the treatment of cervical schwannomas: our experience

PURPOSE

The purpose of our paper is to illustrate our experience with minimally invasive approaches for the treatment of cervical schwannomas. Moreover, a brief review of the literature was conducted.

METHODS

All data regarding patients treated for cervical schwannomas were retrospectively revised. Site, size and extension of the lesions and preoperative neurological status were obtained through re-examination of neuroimaging and clinical records. Postoperative clinical examinations and radiological images were available for all patients. The clinical course was documented using the visual analog scale (VAS), Karnofsky score (KPS) and the Klekamp-Samii score system.

RESULTS

Sixteen patients harboring cervical schwannomas were treated from 2003 to 2009. Hemilaminectomy was performed in eight cases, subtotal hemilaminectomy in four cases, interlaminar fenestration in two cases, osteoplastic hemilaminotomy and laminoplasty in one case each. Postoperative neuroimaging revealed complete removal of the lesion and no signs of spinal instability. At discharge, neurological improvement was observed in 14 patients and all patients demonstrated reduction of VAS score and improvement of KPS and Klekamp-Samii's score.

CONCLUSIONS

Minimal access procedures are increasingly gaining popularity but their use is poorly described in the treatment of cervical tumors. Less invasive approaches may effectively be used instead of traditional laminectomy in the treatment of cervical tumors, especially schwannomas, providing less iatrogenic traumatism and preventing postsurgical spinal instability. Modern neuroimaging allows adequate preoperative planning and microsurgical techniques provide adequate execution of the surgical act. The procedure has to be tailored case by case considering the specific lesional features and the individual anatomical situation.

Safety and efficacy of intradural extramedullary spinal tumor removal using a minimally invasive approach

BACKGROUND

Although minimally invasive surgery for intradural tumors offers the potential benefits of less postoperative pain, a quicker recovery, and the avoidance of long-term instability from multilevel laminectomy, there are concerns over whether one can safely and effectively remove intradural extramedullary tumors in a fashion comparable to open techniques and whether the advantages of minimally invasive surgery are clinically significant.

OBJECTIVE

To review our early experience with minimally invasive techniques for intradural extramedullary tumors of the spine.

METHODS

Thirteen intradural tumors (1 cervical, 6 thoracic, 6 lumbar) in 11 patients were operated on using a muscle-splitting, tube-assisted paramedian oblique approach with hemilaminectomy to access the spinal canal while preserving the spinous process and ligaments. Fluoroscopy and navigation were used to determine the surgical level in all thoracic and lumbar cases.

RESULTS

Satisfactory tumor resection using standard microsurgical techniques was achieved in all but 1 case using a minimally invasive approach. Surgical time and intraoperative blood loss were favorable compared with our open technique cases. There was no postoperative morbidity with the minimally invasive approach, although in 2 patients with tumors in the mid- and upper thoracic spine, the surgical incision was inaccurately placed by 1 level. In 1 case, the approach was converted to open when the tumor could not be found, and postoperatively there was a cerebrospinal fluid leak with infection that required readmission.

CONCLUSION

Intradural extramedullary tumors can be safely and effectively removed using minimally invasive techniques. The pros and cons of minimally invasive vs open surgery are discussed.

Minimally invasive tethered cord release in adults: a comparison of open and mini-open approaches

Object

Symptomatic tethered cord and associated anomalies such as diastematomyelia rarely present during adulthood but can cause significant pain as well as motor, sensory, and bladder dysfunction. As with children, studies have shown that surgical detethering may provide improvement in pain and neurological deficits. Typical surgical management involves an open laminectomy, sectioning of the filum terminale, and exploration of the split cord malformation. Such open approaches, however, cause significant paraspinous muscle trauma and scarring. Recent advances in minimally invasive techniques allow for access to the spine and thecal sac while minimizing associated muscular trauma. The authors present a comparison of open versus minimally invasive surgery to treat adult tethered cord syndrome.

Methods

Six adult patients underwent surgical release of a tethered spinal cord (2 of them also had diastematomyelia). The mean age of the patients was 47.78 years (range 31–64 years). All medical records and images were retrospectively reviewed. Three of the patients underwent traditional open laminectomies for detethering (open group) while the other 3 patients underwent minimally invasive (mini-open) spinal cord detethering. The length of the incision, length of stay, estimated blood loss, and complications were compared between the 2 groups.

Results

All 6 patients had tethered spinal cords, and 1 patient in each group had diastematomyelia. The mean estimated blood loss during surgery (300 ml in the open group vs 167 ml in the mini-open group, p = 0.313) and the mean length of stay (7 days in the open group vs 6.3 days in the mini-open group, p = 0.718) were similar between the 2 groups. The incision length was half as long in the mini-open group versus the open group. However, 1 patient in the mini-open group developed a postoperative pseudomeningocele requiring surgical revision, whereas the open group had no revision surgeries.

Conclusions

Cases of symptomatic diastematomyelia and tethered cord in adults can be safely and effectively explored through a mini-open approach. In this small case series, the authors did find that the mini-open group had an incision that was 50% smaller than the open group, but they did not find a significant clinical difference between the groups.

Surgical site infection rates after minimally invasive spinal surgery

OBJECT

Postoperative surgical site infections (SSIs) have been reported after 2-6% of spinal surgeries in most large series. The incidence of SSI can be < 1% after decompressive procedures and > 10% after instrumented fusions. Anecdotal evidence has suggested that there is a lower rate of SSI when minimally invasive techniques are used.

METHODS

A retrospective review of prospectively collected databases of consecutive patients who underwent minimally invasive spinal surgery was performed. Minimally invasive spinal surgery was defined as any spinal procedure performed through a tubular retractor system. All surgeries were performed under standard sterile conditions with preoperative antibiotic prophylaxis. The databases were reviewed for any infectious complications. Cases of SSI were identified and reviewed for clinically relevant details. The incidence of postoperative SSIs was then calculated for the entire cohort as well as for subgroups based on the type of procedure performed, and then compared with an analogous series selected from an extensive literature review.

RESULTS

The authors performed 1338 minimally invasive spinal surgeries in 1274 patients of average age 55.5 years. The primary diagnosis was degenerative in nature in 93% of cases. A single minimally invasive spinal surgery procedure was undertaken in 1213 patients, 2 procedures in 58, and 3 procedures in 3 patients. The region of surgery was lumbar in 85%, cervical in 12%, and thoracic in 3%. Simple decompressive procedures comprised 78%, instrumented arthrodeses 20%, and minimally invasive intradural procedures 2% of the collected cases. Three postoperative SSIs were detected, 2 were superficial and 1 deep. The procedural rate of SSI for simple decompression was 0.10%, and for minimally invasive fusion/fixation was 0.74%. The total SSI rate for the entire group was only 0.22%.

CONCLUSIONS

Minimally invasive spinal surgery techniques may reduce postoperative wound infections as much as 10-fold compared with other large, modern series of open spinal surgery published in the literature.

MINIMALLY INVASIVE POSTERIOR OSTEOTOMIES

OBJECTIVE

Surgery for thoracolumbar deformity can lead to significant muscle injury, excessive blood loss, and severe postoperative pain. The aim of the following studies was to determine the feasibility of minimally invasive posterior thoracic corpectomy and thoracolumbar osteotomy techniques for deformity in human cadavers and select clinical cases.

METHODS

Human cadaveric specimens were procured for thoracic corpectomy and Smith-Petersen and pedicle subtraction osteotomy using a minimally invasive approach. Post-procedural computed tomography was used to assess the degree of decompression following corpectomy and the extent of bone resection after osteotomy. Pre and post-osteotomy closure Cobb angles were measured to evaluate the degree of correction achieved.

RESULTS

The minimally invasive lateral extracavitary approach for thoracic corpectomy provided adequate exposure and allowed excellent spinal canal decompression while minimizing tissue disruption. Nearly complete osteotomies of both types could be achieved through a tubular retractor with a modest change in Cobb angle.

CONCLUSION

These techniques may play a role in deformity surgery for select cases with further technological advancements.

Clinical feasibility of minimally invasive cervical laminoplasty

Minimally invasive approaches to the cervical spine for lateral disc herniation or foraminal stenosis have recently been described. Lower rates of blood loss, decreased narcotic dependence, and less tissue destruction as well as shorter hospital stays are all advantages of utilizing these techniques. These observations can also be realized with a minimal access approach to cervical laminoplasty. Multiple levels of the cervical spine can be treated from a posterior approach with the potential to decrease the incidences of postoperative axial neck pain and kyphotic deformity. In this report the authors present a concise history of the open laminoplasty technique, provide data from previous cadaveric studies (6 cases) along with recent clinical experience for minimally invasive laminoplasty, and describe the advantages and challenges of this novel procedure.

Minimally invasive posterior thoracic fusion

Thoracic spine fusion may be indicated in the surgical treatment of a wide range of pathologies, including trauma, deformity, tumor, and infection. Conventional open procedures for surgical treatment of thoracic spine disease can be associated with significant approach-related morbidity, which has motivated the development of minimally invasive approaches. Thoracoscopy and, later, video-assisted thoracoscopic surgery were developed to address diseases of the thoracic cavity and subsequently adapted for thoracic spine surgery. Although video-assisted thoracoscopic surgery has been used to treat a variety of thoracic spine diseases, its relatively steep learning curve and high rate of pulmonary complications have limited its widespread use. These limitations have motivated the development of minimally invasive posterior approaches to address thoracic spine pathology without the added risk of morbidity involved in surgically entering the chest. Many of these advances are ongoing and represent the forefront of minimally invasive spine surgery. As these techniques are developed and applied, it will be important to assess their equivalence or superiority in comparison with standard open techniques using prospective trials. In this paper the authors focus on minimally invasive posterior thoracic procedures that include fusion, and provide a review of the current literature, a discussion of future pathways for development, and case examples. The topic is divided by pathology into sections including trauma, deformity, spinal column tumors, and osteomyelitis.

Minimally invasive removal of an extradural intraradicular lumbar schwannoma

OBJECTIVE

Surgical exposure of peripheral lumbar schwannomas often requires extensive muscle mobilization which results in significant postoperative pain. We describe an alternative minimally invasive surgical technique for the treatment of such lesions.

METHODS

We report the case of a patient with an extradural intraradicular schwannoma of the L4 root that was treated with a minimally invasive transmuscular approach by using tubular retractors.

RESULTS

Muscle trauma and intraoperative blood loss were negligible. The postoperative course was uneventfull. There was no additional morbidity associated with the approach. The patient was discharged 72 h after the procedure.

CONCLUSIONS

In selected cases extradural intraradicular lumbar schwannomas can be treated adequately with a minimally invasive transmuscular approach.