Complication management with minimally invasive spine procedures

Complication Avoidance in Spine Surgery

The outcomes of spine surgery are closely related to postoperative morbidity. Therefore, an experienced surgeon must be aware of various complications and should apply all necessary preventive measures to avoid them. It is widely considered that complications of spine surgery are underreported and that their real incidence is much higher than expected. This review highlights methods to prevent various types of morbidity that may be encountered during different spinal procedures, considering general complications, approach-related complications, fusion- and implant-related complications, and systemic complications.

A modified oblique lumbar interbody fusion: A better way to establish an exposure under direct microscopic vision

Study design

This is a retrospective study.

Objective

To demonstrate a modified oblique lumbar interbody fusion (OILF) technique for L1-L5.

Methods

The modified technique splits anterior portion of psoas belly to access the oblique corridor (OC) anteroinferior to psoas, minimizing psoas manipulation and retraction and avoiding nerve injury while offering excellent microscopic visualization. Psoas weakness and neurovascular complication rates in patients treated with traditional OLIF (T-OLIF) or anteroinferior psoas OLIF (AP-OLIF) were retrospectively reviewed. Clinical outcomes were also reviewed.

Results

A total of 162 cases treated with T-OLIF (n = 73) and AP-OLIF (n = 89) for degenerative lumbar disease were included. The mean operative time and blood loss were less with AP-OLIF (P < 0.01). Approach related complications were 14 (19.1%) with T-OLIF and 4 (4.5%) with AP-OLIF. Postoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) scores improved in both T-OIF and AP-OIF groups (P < 0.01).

Conclusion

The modified OLIF technique (AP-OLIF) is characterized by an easy exposure of the lumbar spine under direct microscopic vision, resulting in less psoas weakness and neurovascular injury.

Minimally invasive technique of monoaxial percutaneous screws and instrumentational maneuvers in thoracolumbar and lumbar fractures

OBJECTIVES

Percutaneous pedicle screw fixation (PPSF) has been a common surgery for treating thoracolumbar and lumbar fractures. Many studies have reported PPSF is associated with poor reduction. We present a reliable method by using short-segment monoaxial percutaneous screws and instrumentational maneuvers to reduce the spine. This study aimed to evaluate radiological and clinical results of this method of reduction compared to traditional polyaxial screws method in treating thoracolumbar and lumbar fractures.

METHODS

From February 2015 to February 2021, 64 patients with thoracolumbar and lumbar fractures in our department were retrospectively reviewed and divided into experimental group and control group according to different treatment methods. The experimental group was treated with short-segment monoaxial percutaneous screws (which were inserted at the adjacent vertebrae one level above, one level below the fracture, and the fractured vertebra) and instrumentational maneuvers method, while the control group was treated with traditional polyaxial screws method. The operation time was recorded. Visual analogue scale (VAS) and Oswestry disability index (ODI) were assessed as the clinical outcomes. The anterior height of the injured vertebra (AVH), the kyphosis cobb angle and the vertebral wedge angle were used to evaluate the fracture radiological reduction.

RESULTS

A total of 64 patients were enrolled including 31 in the experimental group and 33 in the control group. There were no significant difference in operation time, AVH, the kyphosis cobb angle,the wedge angle of injured vertebra,VAS and ODI score between the two groups in preoperation. In each group, there were significant differences in the AVH, the kyphosis cobb angle and wedge angle of injured vertebra between preoperation and immediate postoperation. In each group, there were significant differences in VAS and ODI score between the preoperation and last follow-up. The total correction rates of AVH,the kyphosis cobb angle and the wedge angle of injured vertebra were significantly higher in the experimental group than those in the control group, while the loss of correction was significantly lower than the control.

CONCLUSIONS

The reduction technique using monoaxial percutaneous screws and instrumentational maneuvers for thoracolumbar and lumbar fractures exhibited better radiological results and satisfying functional outcomes when compared to traditional polyaxial screws.

Oblique Lumbar Interbody Fusion Using a Stand-Alone Construct for the Treatment of Adjacent-Segment Lumbar Degenerative Disease

Objective

Adjacent-segment disease (ASD) is common in patients undergone previous lumbar fusion. A typical revision treatment from posterior approach requires management of postoperative scar tissue and previously implanted instrumentation. An oblique lumbar interbody fusion (OLIF) approach allows surgeon to reduce the potential risk of posterior approach. This study aimed to analyze the clinical and radiographic efficacy of stand-alone OLIF for the treatment of lumbar adjacent-segment disease.

Methods

A total of 13 consecutive patients who underwent stand-alone OLIF for the treatment of adjacent-segment disease from December 2016 to January 2019 were reviewed. Visual analog scale (VAS) of back pain and leg pain and the Oswestry Disability Index (ODI) before surgery and at last postoperative clinic visits were obtained. Radiography, CT and MRI before and at last follow-up after surgery was evaluated in all patients.

Results

During the study period, 13 cases were successfully treated with stand-alone OLIF. The mean follow-up was 17.7 ± 8.3 months. The back pain VAS improved from 6.2 ± 1.0 to 2.0 ± 1.1 (P < 0.01), and the leg pain VAS improved from 7.0 ± 1.9 to 1.0 ± 0.9 (P < 0.01). ODI improved from 28.0 ± 7.5 to 10.8 ± 4.0 (P < 0.01). The disc height (DH) increased from 9 ± 2 to 12 ± 2 mm (P < 0.01), the cross-sectional area (CSA) of spinal canal increased from 85 ± 26 to 132 ± 24 mm² (P < 0.01), the foraminal height increased from 17 ± 2 to 21 ± 3 mm (P < 0.01) and the CSA of foramen increased from 95 ± 25 to 155 ± 36 mm² (P < 0.01). Cage subsidence was observed in 2 cases.

Conclusions

Stand-alone OLIF provides a safe and effective alternative way to treat ASD.

Effects of Different Trunk Training Methods for Chronic Low Back Pain: A Meta-Analysis

We conducted a systematic review and meta-analysis comparing motor control, isometric, and isotonic trunk training intervention for pain, disability, and re-injury risk reduction in chronic low back pain patients. The EMBASE, MEDLINE, CENTRAL, PsycINFO, SPORTDiscus, and CINAHL databases were searched from inception until 25 February 2021 for chronic low back pain intervention based on any trunk training. Outcomes include the Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ) for disability, the Numerical Pain Rating Scale (NPRS) for pain, and the Sorensen Test (ST) for future risk of re-injury. Isometric training was superior to the control with a mean difference (MD) = −1.66, 95% confidence interval (CI) [−2.30, −1.01] in pain reduction; MD = −7.94, 95% CI [−10.29, −5.59] in ODI; MD = −3.21, 95% CI [−4.83, −1.60] in RMDQ; and MD = 56.35 s, 95% CI [51.81 s, 60.90 s] in ST. Motor control was superior to the control with a MD = −2.44, 95% CI [−3.10, −1.79] in NPRS; MD = −8.32, 95% CI [−13.43, −3.22] in ODI; and MD = −3.58, 95% CI [−5.13, −2.03] in RMDQ. Isometric and motor control methods can effectively reduce pain and disability, with the isometric method reducing re-injury risk.

Magnetic Resonance Imaging Study of Oblique Corridor and Trajectory to L1-L5 Intervertebral Disks in Lateral Position

OBJECTIVE

This study investigated the retroperitoneal oblique corridor and trajectory of L1-L5 as the lateral surgical access to the intervertebral disks in the Chinese population and detected the potential relationship between the corridor or trajectory and vertebral parameters, including disk axis, psoas muscle, and retroperitoneal vessel.

METHODS

Seventy magnetic resonance imaging studies performed from January 2017 to January 2019 were investigated. The oblique corridor was defined as the distance between the left lateral border of the retroperitoneal vessel and the anterior border of psoas. The trajectory was defined as the distance between the retroperitoneal vessel and lumbar plexus.

RESULTS

The oblique corridor analysis to L1-L5 disks have the following mean distances: L1-2 13.36 mm, L2-3 13.36 mm, L3-4 12.37 mm, and L4-5 10.36 mm. There was no difference in the L1-L5 corridor between genders. And the position of retroperitoneal vessel was negatively correlated with the corridor width. The trajectory measurements to L1-L5 disks have the following mean distances: L1-2 27.44 mm, L2-3 30.86 mm, L3-4 30.73 mm, and L4-5 24.36 mm. Moreover, the vertebral parameters, including the disk axis and psoas muscle, were positively correlated with the trajectory width. Otherwise, the position of retroperitoneal vessel was negatively correlated with the trajectory width.

CONCLUSIONS

Compared with previous studies, the safe surgical area of the Chinese is generally smaller than that of Caucasian. The position of the retroperitoneal vessel is the vital potential to limit the corridor and trajectory. Preoperative assessment of vertebral parameters, especially vascular structure, is essential for planning surgical process.

The Anatomic Characteristics of the Retroperitoneal Oblique Corridor to the L1-S1 Intervertebral Disc Spaces

STUDY DESIGN

This is a cross-sectional study.

OBJECTIVE

To investigate the oblique corridor to the L1-S1 intervertebral disc space between the psoas muscle and the great vessels in cadaveric specimens bilaterally and the location of genitofemoral nerve and the diaphragmatic crura relative to the oblique corridor.

SUMMARY OF BACKGROUND DATA

Although use of oblique lumbar interbody fusion is rapidly expanding, the morphometric data related to the procedure are limited.

METHODS

Twelve fresh-frozen full-torso cadaveric specimens were dissected to examine the oblique corridor to access the L1-S1 space in a static state and with mild retraction of the psoas. The level at which the genitofemoral nerve pierces from the psoas major and the diaphragmatic crura originate from the lumbar vertebral body was also investigated.

RESULTS

The mean width of oblique corridor in the static state and with mild psoas retraction, respectively, were as follows: on the right side: (L1-2) 13.33 and 16.75 mm; (L2-3) 15.42 and 21.42 mm; (L3-4) 16.58 and 22.67 mm; (L4-5) 12.75 and 21.17 mm; (L5-S1) 5.92 and 12.00 mm; on the left side: (L1-2) 16.75 and 19.67 mm; (L2-3) 18.50 and 25.33 mm; (L3-4) 20.58 and 28.00 mm; (L4-5) 18.17 and 26.08 mm; and (L5-S1) 5.83 and 12.00 mm. The level at which the genitofemoral nerve pierces from the psoas major was between L2 and L4. The diaphragmatic crura originates from L1 to L3.

CONCLUSION

The oblique corridor allows access to the L1-L5 discs from both sides, but it is larger on the left side. The corridor between the iliac vessels and the psoas for L5-S1 is difficult to be applied clinically. Mild psoas retraction can moderately enlarge the oblique corridor. The genitofemoral nerve and diaphragmatic crura may be encountered in this approach and should be carefully observed.

LEVEL OF EVIDENCE

5.

The effect of minimal invasive techniques and physiotherapy on pain and disability in elderly: A retrospective study

BACKGROUND

Low back pain is one of the major musculoskeletal problems seen in elderly, and it's the fifth common cause for hospitalization.

OBJECTIVE

This retrospective study has determined whether minimal invasive techniques or physiotherapy methods are effective for decreasing pain and improving functions in the geriatric population.

METHODS

A retrospective design was used in this study. Sixty-one patients aged ⩾ 65, who were referred to physiotherapy enrolled in the study. The patients were divided into 2 groups; Group 1 received minimal invasive techniques, whereas Group 2 had no surgery or no minimal invasive application. Pressure Pain Threshold (PPT) was used for perceived pain intensity, Semmes Weinstein Monofilaments (SWM) was used to assess tactile sensitivity, and Oswestry Disability Index (ODI) was used to determine perceived functional disability. Physiotherapy methods including soft tissue mobilizations, muscle-energy techniques and spinal stabilization exercises were used in the treatment of all patients. The outcomes were evaluated pre- and post-physiotherapy applications.

RESULTS

Significant improvements in PPT were shown in both groups after physiotherapy treatment as to baseline (p< 0.05). Despite the significant improvements in PPT values of all muscles in Group 1, Group 2 had significant improvements in PPT except Hamstring muscles (p< 0.05). Functional disability levels of both groups reduced acc. to ODI, improvement in disability scores was only significant in Group 1 (p< 0.05).

CONCLUSION

Although both treatments showed pain relief, functional restoration and improvement in hypoesthesia existence; there was no superiority of physiotherapy alone over physiotherapy added minimal invasive treatments in terms of parameters.

First spine surgery utilizing real-time image-guided robotic assistance

Robotics in spinal surgery has significant potential benefits for both surgeons and patients, including reduced surgeon fatigue, improved screw accuracy, decreased radiation exposure, greater options for minimally invasive surgery, and less time required to train residents on techniques that can have steep learning curves. However, previous robotic systems have several drawbacks, which are addressed by the innovative ExcelsiusGPS^TM robotic system. The robot is secured to the operating room floor, not the patient. It has a rigid external arm that facilitates direct transpedicular drilling and screw placement, without requiring K-wires. In addition, the ExcelsisuGPS^TM has integrated neuronavigation, not present in other systems. It also has surveillance marker that immediately alerts the surgeon in the event of loss of registration, and a lateral force meter to alert the surgeon in the event of skiving. Here, we present the first spinal surgery performed with the assistance of this newly approved robot. The surgery was performed with excellent screw placement, minimal radiation exposure to the patient and surgeon, and the patient had a favorable outcome. We report the first operative case with the ExcelsisuGPS^TM, and the first spine surgery utilizing real-time image-guided robotic assistance.

Radiographic and Clinical Outcomes following Combined Oblique Lumbar Interbody Fusion and Lateral Instrumentation for the Treatment of Degenerative Spine Deformity: A Preliminary Retrospective Study

Objective

The authors recently used a combination of minimally invasive oblique lumbar interbody fusion (OLIF) and lateral fixation for the treatment of degenerative spine deformity. The early results were promising. Radiographic and clinical results as well as complications were retrospectively assessed in the current study.

Methods

Eleven patients with degenerative spine deformity underwent combined OLIF and lateral instrumentation without real-time electromyography (EMG) monitoring. Radiographic measurements including coronal Cobb angle, central sacral vertebral line (CSVL), lumbar lordosis (LL), sagittal vertebral axis (SVA), pelvic tilt (PT), and LL-PI (pelvic incidence) mismatch were taken preoperatively and at last follow-up postoperatively in all patients. Concurrently, the visual analog score (VAS) for back pain and the Oswestry Disability Index (ODI) score were used to assess clinical outcomes. The fusion rate of OLIF cage, total blood loss, operation time, hospital stay, and complications were also evaluated.

Results

At last follow-up, all patients who underwent combined OLIF and lateral instrumentation achieved statistically significant improvement in coronal Cobb angle (from 15.3±4.7° to 5.9±3.1°, p < 0.01), LL (from 34.3±9.0° to 48.2±8.5°, p < 0.01), PT (from 24.2±9.6° to 16.2±6.0°, p < 0.01), LL-PI mismatch (from 15.4±8.7° to 7.0±3.7°, p < 0.01), CSVL (from 2.1±2.2cm to 0.7±0.9cm, p = 0.01), and SVA (from 7.0±3.9cm to 2.9±1.8cm, p < 0.01). VAS for back pain (from 6.9±1.4 to 2.0±0.9, p < 0.05) and ODI (from 39.5±3.1 to 21.9±3.6, p < 0.01) improved significantly after surgery.

Conclusions

A combination of OLIF and lateral instrumentation is an effective and safety means of achieving correction of both coronal and sagittal deformity, resulting in improvement of quality of life in patients with degenerative spine deformity. It is a promising way to treat patients with moderate degenerative spine deformity.

Robot-assisted multi-level anterior lumbar interbody fusion: an anatomical study

BACKGROUND

Minimally invasive surgical approaches still provide limited exposure. Access to the L2-L5 intervertebral discs during a single procedure is challenging and often requires repositioning of the patient and adopting an alternative approach.

OBJECTIVES

Investigate the windows to the L2-L5 intervertebral discs to assess the dimensions of the interbody implants suitable for the procedure and evaluate the feasibility of multi-level lumbar intervertebral disc surgery in robot-assisted surgery (RAS) METHODS: Sixteen fresh-frozen cadaveric specimens underwent a retroperitoneal approach to access the L2-L5 intervertebral discs. The L2-L3 to L4-L5 windows were defined as the distance between the left lateral border of the aorta (or nearest common iliac vessel) and the medial border of the psoas, measured in a static state and after gentle medial retraction of the vascular structures. Two living porcine specimens and one cadaveric specimen underwent da Vinci robot-assisted transperitoneal approach to expose the L2-L3 to L4-L5 intervertebral discs and perform multi-level discectomy and interbody implant placement.

RESULTS

The L2-L3 to L4-L5 intervertebral disc windows significantly increased from a static to a retracted state (p < 0.05). The mean L2-L3, L3-L4, and L4-L5 windows measured respectively 20.1, 21.6, and 19.6 mm in the static state, and 27.2, 30.9, and 30.3 mm after gentle vascular retraction. The intervertebral windows from L2-L3 to L4-L5 were successfully exposed through an anterior transperitoneal approach with the da Vinci robot on the cadaveric and living porcine specimens, and interbody implants were inserted.

CONCLUSION

RAS appears to be feasible for a mini-invasive multi-level lumbar intervertebral disc surgery. The RAS procedure, longer and more expensive than conventional MIS approaches, should be reserved for elective patients.

Complications of percutaneous pedicle screw fixation in treating thoracolumbar and lumbar fracture

Percutaneous pedicle screw fixation (PPSF) has been a popular approach for treating thoracolumbar and lumbar fracture, and its relevant complications have been gradually recognized. This study aimed to summarize the complications of PPSF in treating thoracolumbar and lumbar fracture as well as the management and outcomes of the complications.We retrospectively analyzed the patients with thoracolumbar and lumbar fracture who were admitted to our department from February 2011 to February 2015 and underwent posterior PPSF. Information on demographics, medical comorbidities, radiographs, and treatment was obtained from hospital medical records and follow-up records. Main outcome indexes included adverse clinical and radiological outcomes during and after surgery.A total of 781 patients were included in this study. Forty-six patients (5.9%) presented with complications during or after surgery. The complications included intraoperative guide wire breakage, abdominal artery injury, spinal dura mater injury, postoperative pedicle screw misplacement, screw breakage, plug screw falling off, connecting rod loosening, poor reduction, and late infection. Among the 39 cases with postoperative complications, 14 underwent revision surgery, and the remaining patients underwent conservative treatment and presented good outcomes.PPSF is associated with the following complications: guide wire rupture, blood vessel injury, cerebrospinal fluid leakage, screw misplacement, poor reduction, failed internal fixation, and infection. A thorough preoperative evaluation, accurate operation, and timely and correct management of complications are critical to achieving satisfactory surgical outcomes.

Does right lateral decubitus position change retroperitoneal oblique corridor? A radiographic evaluation from L1 to L5

PURPOSE

To determine if the retroperitoneal oblique corridor will be affected by right lateral decubitus position.

METHODS

Forty volunteers were randomly enrolled and MRI scan was performed from L1 to L5 in supine and right lateral decubitus positions, respectively. In images across the center of each disc, O was defined as the center of a disc and A (supine) or A' (right lateral decubitus) was located in left lateral border of the aorta or the iliac artery; B (supine) or B' (right lateral decubitus) was on the anterior medial border of the psoas. The distance of AB and A'B' (Recorded as A-Ps and A-Pr, respectively) at each level was recorded and compared to each other. The relationships between A-Pr, sex, BMI and relative psoas cross-sectional area (PCSA) at each level were also evaluated.

RESULTS

A-Pr was significantly smaller than A-Ps at L1/2, L2/3 and L3/4 (All p < 0.05); there was no significantly difference of A-Pr between all levels (p = 0.105), but L1/2 seemed to be larger than L3/4, followed by L2/3 and L4/5; A-Pr at each level was not affected by sex (All p > 0.05); linear relationships were found between A-Pr, BMI and PCSA at L1/2 and L3/4.

CONCLUSIONS

ROC at L1/2, L2/3 and L3/4 will significantly decrease from supine to right lateral decubitus position and the reason may be due to the relaxed psoas deformation. Using MRI images in supine position for pre-operatively ROC evaluation is not accurate. Spine surgeon should also be more cautious when OLIF is performed at L4/5 where ROC is the smallest. Patients from Asia and those with strong psoas major at L1/2 and L3/4 are also associated with relatively narrow ROC.

Application of the Flexible CO2 Laser in Minimally Invasive Laminectomies: Technical Note

Background Minimally invasive laminectomy is a very effective surgical method for treating lumbar stenosis. However, this technique can be technically difficult, especially in patients suffering from severe stenosis. The contralateral decompression from a unilateral approach can result in durotomy during removal of the hypertrophied ligamentum flavum. This complication can be difficult to treat through a small working channel. Objective To detail our group's operative experience with the CO2 laser and discuss our results and previous studies in the literature reporting results.  Methods The CO2 laser (Omniguide, Boston, MA) was investigated in the surgical ablation of the contralateral ligamentum flavum during minimally invasive laminectomies. Forty levels have been investigated thus far. The amount of voltage needed to adequately desiccate and remove the ligamentum flavum safely as well as the effectiveness of this technique were investigated. Results The contralateral ligamentum flavum could be removed effectively using the 9 to 11 watt continuous wavelength (10,600 nanometer) power setting on the CO2 laser. Shrinkage of the contralateral ligamentum flavum facilitated its removal using a number 2 Kerrison Punch. No durotomies occurred, and the use of the laser did not significantly lengthen operative times.  Conclusions The CO2 laser appears to be a useful tool in the armamentarium of instruments available to the minimally invasive spine surgeon and may help to reduce the incidence of durotomies when performing minimally invasive laminectomies.

Trans-Sacral Epiduroscopic Laser Decompression for Symptomatic Lumbar Disc Herniation: A Preliminary Case Series

OBJECTIVE

The purpose of this study was to investigate the effect of trans-sacral epiduroscopic laser decompression (SELD) in patients with a herniated lumbar disc.

METHODS

This prospective case series study was designed to determine the outcomes of SELD with regard to reducing pain and improving the functional status in patients with low back pain (LBP) and radiculopathy caused by definitive neural compression confirmed by MRI. A total of 250 patients with LBP and simultaneous radiculopathy underwent SELD by applying a Ho:YAG laser. Clinical outcomes were evaluated using the visual analogue scale (VAS) score for LBP, and radiculopathy and functional status were measured using the Oswestry Disability Index (ODI).

RESULTS

At 2 weeks after the procedure, the average VAS score for leg pain decreased to 3.6 from 7.1 (p < 0.01), and the average VAS score for back pain decreased to 4.1 from 5.9 (p < 0.01). At 3 months, the average VAS scores for leg and back pain decreased to 2.6 and 2.7, respectively. The mean ODI improved from 50 to 19 at 2 weeks postoperatively and further decreased to 12 at 3 months postoperatively.

CONCLUSIONS

The VAS score and ODI significantly improved after SELD in herniated nucleus pulposus (HNP) patients with LBP and radiculopathy. Postoperative MRI showed a notable decrease in the HNP size and a reduction in neural compression. SELD is suggested to be an effective therapeutic modality for patients with symptomatic HNP.

Retroperitoneal oblique corridor to the L2-S1 intervertebral discs: an MRI study

OBJECT The purpose of this study was to analyze MR images of the lumbar spine and document: 1) the oblique corridor at each lumbar disc level between the psoas muscle and the great vessels, and 2) oblique access to the L5-S1 disc space. Access to the lumbar spine without disruption of the psoas muscle could translate into decreased frequency of postoperative neurological complications observed after a transpsoas approach. The authors investigated the retroperitoneal oblique corridor of L2-S1 as a means of surgical access to the intervertebral discs. This oblique approach avoids the psoas muscle and is a safe and potentially superior alternative to the lateral transpsoas approach used by many surgeons. METHODS One hundred thirty-three MRI studies performed between May 4, 2012, and February 27, 2013, were randomly selected from the authors' database. Thirty-three MR images were excluded due to technical issues or altered lumbar anatomy due to previous spine surgery. The oblique corridor was defined as the distance between the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5-S1 oblique corridor was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel (axial view) and vertically to the first vascular structure that crossed midline (sagittal view). RESULTS The oblique corridor measurements to the L2-5 discs have the following mean distances: L2-3 = 16.04 mm, L3-4 = 14.21 mm, and L4-5 = 10.28 mm. The L5-S1 corridor mean distance was 10 mm between midline and left common iliac vessel, and 10.13 mm from the first midline vessel to the inferior endplate of L-5. The bifurcation of the aorta and confluence of the vena cava were also analyzed in this study. The aortic bifurcation was found at the L-3 vertebral body in 2% of the MR images, at the L3-4 disc in 5%, at the L-4 vertebral body in 43%, at the L4-5 disc in 11%, and at the L-5 vertebral body in 9%. The confluence of the iliac veins was found at lower levels: 45% at the L-4 level, 19.39% at the L4-5 intervertebral disc, and 34% at the L-5 vertebral body. CONCLUSIONS An oblique corridor of access to the L2-5 discs was found in 90% of the MR images (99% access to L2-3, 100% access to L3-4, and 91% access to L4-5). Access to the L5-S1 disc was also established in 69% of the MR images analyzed. The lower the confluence of iliac veins, the less probable it was that access to the L5-S1 intervertebral disc space was observed. These findings support the use of lumbar MRI as a tool to predetermine the presence of an oblique corridor for access to the L2-S1 intervertebral disc spaces prior to lumbar spine surgery.

Analysis of 1014 consecutive operative cases to determine the utility of intraoperative neurophysiological data

Introduction:

Intraoperative neurophysiological monitoring (IOM) during neurosurgical procedures has become the standard of care at tertiary care medical centers. While prospective data regarding the clinical utility of IOM are conspicuously lacking, retrospective analyses continue to provide useful information regarding surgeon responses to reported waveform changes.

Methods:

Data regarding clinical presentation, operative course, IOM, and postoperative neurological examination were compiled from a database of 1014 cranial and spinal surgical cases at a tertiary care medical center from 2005 to 2011. IOM modalities utilized included somatosensory evoked potentials, transcranial motor evoked potentials, pedicle screw stimulation, and electromyography. Surgeon responses to changes in IOM waveforms were recorded.

Results:

Changes in IOM waveforms indicating potential injury were present in 87 of 1014 cases (8.6%). In 23 of the 87 cases (26.4%), the surgeon responded by repositioning the patient (n = 12), repositioning retractors (n = 1) or implanted instrumentation (n = 9), or by stopping surgery (n = 1). Loss of IOM waveforms predicted postoperative neurological deficit in 10 cases (11.5% of cases with IOM changes).

Conclusions:

In the largest IOM series to date, we report that the surgeon responded by appropriate interventions in over 25% of cases during which there were IOM indicators of potential harm to neural structures. Prospective studies remain to be undertaken to adequately evaluate the utility of IOM in changing surgeon behavior. Our data is in agreement with previous observations in indicating a trend that supports the continued use of IOM.

Retroperitoneal oblique corridor to the L2-S1 intervertebral discs in the lateral position: an anatomic study

OBJECT

Access to the intervertebral discs from L2-S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4-5 disc access, and the L5-S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2-S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus.

METHODS

Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2-S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2-5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5-S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline.

RESULTS

The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2-3, 18.60 mm and 25.50 mm; at L3-4, 19.25 mm and 27.05 mm; and at L4-5, 15.00 mm and 24.45 mm. The L5-S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel.

CONCLUSIONS

The oblique corridor allows access to the L2-S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5-S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2-S1 discs.

A rare cause of postoperative paraplegia in minimally invasive spine surgery

STUDY DESIGN

A case report.

OBJECTIVE

To present a patient who underwent a minimally invasive transforaminal lumbar interbody fusion who postoperatively developed paraplegia as a rare complication of a Kirschner wire (K-wire).

SUMMARY OF BACKGROUND DATA

The few complications of K-wires that have been reported include, dural tears and damage to intra-abdominal structures.

METHODS

A case report of a rare complication of a K-wire is reported and the relevant literature was then reviewed.

RESULTS

An 85-year-old female with an anterolisthesis at L4-L5 underwent a minimally invasive transforaminal lumbar interbody fusion. Postoperatively she developed paraplegia. A subdural hematoma from T12 to the sacrum was found and evacuated. It is proposed that this rare complication is a result of a K-wire.

CONCLUSION

Care must be taken with the use of K-wires and additional measures should be carried out such as the marking of its position and radiological confirmation of depth.

LEVEL OF EVIDENCE

5.

Use of the da Vinci Minimally Invasive Robotic System for Resection of a Complicated Paraspinal Schwannoma With Thoracic Extension

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