The routine intra-operative use of pulse oximetry for monitoring can prevent severe thromboembolic complications in anterior surgery

Anterior Lumbar Interbody Fusion Versus Oblique Lumbar Interbody Fusion Versus Lateral Lumbar Interbody Fusion: Which One in Which Patient?

Anterolateral approaches to the lumbar spine provide direct access to the disc space. These techniques facilitate thorough discectomy, which is essential for successful arthrodesis. They improve segmental lordosis without osteotomy and indirectly decompress neural elements in carefully selected patients. Benefits include shorter operative times, reduced blood loss, and rapid postoperative mobilization compared to posterior approaches. Each technique has specific advantages and limitations, thus none is inherently superior to another. Detailed knowledge of these techniques is essential for modern spine surgeon to provide personalized operative plan for each patient.

Incidence of temporary intraoperative iliac artery occlusion during anterior spinal surgery

Background

Thromboembolic complications in anterior lumbar spinal surgery can rarely result in limb loss. Iliac vessel retraction can temporarily occlude the iliac artery risking thromboembolic sequelae. Studies estimate the incidence of iliac artery thrombosis at 0.45%. Brief intraoperative heparinization can potentially mitigate this risk. We aim to quantify the incidence of temporary iliac artery occlusion (TIAO) and examine its association with potential risk factors (sex, BMI, target disc level, and type of prosthesis).

Methods

Retrospective analysis of consecutive patients undergoing anterior lumbar spinal surgery by a single vascular surgeon and 5 spinal neurosurgeons between 2009 and 2022. Patients underwent single or double-level total disc replacement (TDR); single, double, or triple-level anterior lumbar interbody fusion (ALIF); or hybrid procedure (combined cranial TDR and caudal ALIF). A pulse oximeter monitored bilateral second toes perfusion. Loss of the waveform, combined with a nonpalpable external iliac artery pulse distal to the retractors was defined as TIAO of the ipsilateral artery. Heparin was administered if TIAO developed.

Results

Of 605 patients (318 males, 287 females), TIAO occurred in 176 patients (29.1%). TIAO occurred in 13.5% of the 377 patients who underwent single or multilevel ALIF and in 42.7% of the 110 patients who underwent single or multilevel TDR (p=.004). In single-level surgery at L5/S1, TIAO occurred in 3.1% of patients. In single-level surgery at L4/5, TIAO occurred in 65.2% of patients overall; the rate was higher for TDR than for ALIF (74.6% vs. 48.5%; p=.01). The TIAO rate was 44.3% in multilevel procedures and 66.1% in hybrid procedures. No patient developed postoperative thrombotic iliac artery occlusion or embolic complications.

Conclusions

TIAO occurred frequently during anterior lumbar exposure (29%). Anterior spinal exposure at L4/5 had a high incidence of TIAO, particularly for TDR, in contrast to L5/S1.

Development of multidisciplinary, evidenced-based protocol recommendations and implementation strategies for anterior lumbar interbody fusion surgery following a literature review

The anterior lumbar interbody fusion (ALIF) procedure involves several surgical specialties, including general, vascular, and spinal surgery due to its unique approach and anatomy involved. It also carries its own set of complications that differentiate it from posterior lumbar fusion surgeries. The demonstrated benefits of treatment guidelines, such as Enhanced Recovery after Surgery in other surgical procedures, and the lack of current recommendations regarding the anterior approach, underscores the need to develop protocols that specifically address the complexities of ALIF. We aimed to create an evidence-based protocol for pre-, intra-, and postoperative care of ALIF patients and implementation strategies for our health system. A 12-member multidisciplinary workgroup convened to develop an evidence-based treatment protocol for ALIF using a Delphi consensus methodology and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system for rating the quality of evidence and strength of protocol recommendations. The quality of evidence, strength of the recommendation and specific implementation strategies for Methodist Health System for each recommendation were described. The literature search resulted in 295 articles that were included in the development of protocol recommendations. No disagreements remained once the authors reviewed the final GRADE assessment of the quality of evidence and strength of the recommendations. Ultimately, there were 39 protocol recommendations, with 16 appropriate preoperative protocol recommendations (out of 17 proposed), 9 appropriate intraoperative recommendations, and 14 appropriate postoperative recommendations. This novel set of evidence-based recommendations is designed to optimize the patient's ALIF experience from the preoperative to the postoperative period.

Rating the incidence of iatrogenic vascular injuries in thoracic and lumbar spine surgery as regards the approach: A PRISMA-based literature review

PURPOSE

To assess the rate, timing of diagnosis, and repairing strategies of vascular injuries in thoracic and lumbar spine surgery as their relationship to the approach.

METHODS

PubMed, Medline, and Embase databases were utilized for a comprehensive literature search based on keywords and mesh terms to find articles reporting iatrogenic vascular injury during thoracic and lumbar spine surgery. English articles published in the last ten years were selected. The search was refined based on best match and relevance.

RESULTS

Fifty-six articles were eligible, for a cumulative volume of 261 lesions. Vascular injuries occurred in 82% of instrumented procedures and in 59% during anterior approaches. The common iliac vein (CIV) was the most involved vessel, injured in 49% of anterior lumbar approaches. Common iliac artery, CIV, and aorta were affected in 40%, 28%, and 28% of posterior approaches, respectively. Segmental arteries were injured in 68% of lateral approaches. Direct vessel laceration occurred in 81% of cases and recognized intraoperatively in 39% of cases.

CONCLUSIONS

Incidence of iatrogenic vascular injuries during thoracic and lumbar spine surgery is low but associated with an overall mortality rate up to 65%, of which less than 1% for anterior approaches and more than 50% for posterior ones. Anterior approaches for instrumented procedures are at risk of direct avulsion of CIV. Posterior instrumented fusions are at risk for injuries of iliac vessels and aorta. Lateral routes are frequently associated with lesions of segmental vessels. Suture repair and endovascular techniques are useful in the management of these severe complications.

Brief intraoperative heparinization and blood loss in anterior lumbar spine surgery

OBJECT

The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. Intraoperative heparin can be administered to prevent thrombosis; however, there is a concern that this will increase the procedural blood loss. The aim of this study was to examine whether intraoperative heparin can be administered without increasing blood loss in anterior lumbar spine surgery.

METHODS

A prospective study of consecutive anterior approaches for lumbar spine surgery was performed between January 2009 and June 2014 by a single vascular surgeon and a single spine surgeon. Patients underwent an anterior lumbar interbody fusion (ALIF) at L4-5 and/or L5-S1, a total disc replacement (TDR) at L4-5 and/or L5-S1, or a hybrid procedure with a TDR at L4-5 and an ALIF at L5-S1. Heparin was administered intravenously when arterial flow to the lower limbs was interrupted during the procedure. Heparin was usually reversed on removal of the causative retraction.

RESULTS

The cohort consisted of 188 patients with a mean age of 41.7 years; 96 (51.1%) were male. Eighty-four patients (44.7%) had an ALIF, 57 (30.3%) had a TDR, and 47 (25.0%) had a hybrid operation with a TDR at L4-5 and an ALIF at L5-S1. One hundred thirty-four patients (71.3%) underwent a single-level procedure (26.9% L4-5 and 73.1% L5-S1) and 54 (28.7%) underwent a 2-level procedure (L4-5 and L5-S1). Seventy-two patients (38.3%) received heparinization intraoperatively. Heparin was predominantly administered during hybrid operations (68.1%), 2-level procedures (70.4%), and procedures involving the L4-5 level (80.6%). There were no intraoperative ischemic vascular complications reported in this series. There was 1 postoperative deep venous thrombosis. The overall mean estimated blood loss (EBL) for the heparin group (389.7 ml) was significantly higher than for the nonheparin group (160.5 ml) (p < 0.0001). However, when all variables were analyzed with multiple linear regression, only the prosthesis used and level treated were found to be significant in blood loss (p < 0.05). The highest blood loss occurred in hybrid procedures (448.1 ml), followed by TDR (302.5 ml) and ALIF (99.7 ml). There were statistically significant differences between the EBL during ALIF compared with TDR and hybrid (p < 0.0001), but not between TDR and hybrid. The L4-5 level was associated with significantly higher blood loss (384.9 ml) compared with L5-S1 (111.4 ml) (p < 0.0001).

CONCLUSIONS

During an anterior exposure for lumbar spine surgery, the administration of heparin does not significantly increase blood loss. The prosthesis used and level treated were found to significantly increase blood loss, with TDR and the L4-5 level having greater blood loss compared with ALIF and L5-S1, respectively. Heparin can be administered safely to help prevent thrombotic intraoperative vascular complications without increasing blood loss.

Access-related complications in anterior lumbar surgery in patients over 60 years of age

PURPOSE

The anterior approach is widely used for access to the lumbar spine in the setting of adult deformity either as a stand-alone procedure or in combined anterior-posterior procedures. Access-related complication rates have so far not been reported in an elderly patient population, in which it has been suggested that anterior lumbar surgery is indicated with caution. Here, the complication rates in patients over 60 years of age are reported.

METHODS

A retrospective chart review in a consecutive series of 31 patients over 60 years of age and in which a retroperitoneal access to the lumbar spine was performed. All charts including anaesthetic charts were reviewed and the patients' demographics, exact surgical procedure, comorbidities, and potential risk factors, as well as intraoperative and vascular complications noted. Patients who had revision anterior surgery, anterior surgery for tumour resection, trauma or infection were excluded.

RESULTS

The average age of patients was 64.9 years, ranging 60-81. Eighteen patients were female and 13 male. The average body mass index was 26.7 ranging 18.5-44.0. The indications for surgery were degenerative scoliosis (12 patients), degenerative spondylosis (7 patients), degenerative spondylolisthesis (5 patients), iatrogenic spondylolisthesis following prior posterior decompression (5 patients), and pseudarthrosis following posterolateral instrumented fusion (2 patients). In 10 patients, a single-level anterior lumbar interbody fusion (ALIF) was carried out (1 L3/4, 5 L4/5, 4 L5/S1) and in 11 patients ALIF was performed on two levels (1 L2-4, 1 L3-5, 9 L4-S1). In three patients, 3 levels from L3 to S1 were approached and in seven patients 4 levels from L2 to S1. Patients with three- and four-level anterior lumbar surgery had higher blood loss than two- and one-level surgery (616 ± 340 vs 439 ± 238, p = 0.036). The overall complication rate was 29% (9/31), which included four vascular injuries and one pulmonary embolism. The vascular complication rate was 13% (4/31) with two arterial and two venous injuries requiring repair. No major blood loss over 2,000 ml occurred.

CONCLUSIONS

Anterior lumbar surgery in an elderly population does not necessarily have higher overall complication rates than in a younger population. The risk of vascular injury requiring repair was higher, but has not resulted in major blood loss and the procedure therefore can be carried out safely. The overall complication rate and blood loss compare favourably to complication rates in posterior adult deformity procedures.

Early results of stand-alone anterior lumbar interbody fusion in iatrogenic spondylolisthesis patients

BACKGROUND

Iatrogenic spondylolisthesis is a challenging condition for spinal surgeons. Posterior surgery in these cases is complicated by poor anatomical landmarks, scar tissue adhesion of muscle and dural structures and difficult access to the intervertebral disc. Anterior interbody fusion provides an alternative treatment method, allowing indirect foraminal decompression, reliable disc clearance and implantation of large surface area implants.

MATERIALS AND METHODS

A retrospective chart review of patients with iatrogenic spondylolisthesis including pre- and post-operative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores was performed. Imaging criteria were pelvic incidence, overall lumbar lordosis and segmental lordosis. In addition, the fusion rate was investigated after 6 months.

RESULTS

Six consecutive patients treated between 2008 and 2011 (4 female, 2 male, mean age 61 ± 7.1 years) were identified. The initially performed surgeries included decompression with or without discectomy; posterior instrumented and non-instrumented fusion. The olisthetic level was in all cases at the decompressed level. All patients were revised with stand-alone anterior interbody fusion devices at the olisthetic level filled with BMP 2. Average ODI dropped from 49 ± 11 % pre-operatively to 26.0 ± 4.0 at 24 months follow-up. VAS average dropped from 7 ± 1 to 2 ± 0. Mean total lordosis of 39.8 ± 2.8° increased to 48.5 ± 4.9° at pelvic incidences of 48.8 ± 6.8° pre-operatively. Mean segmental lordosis at L4/5 improved from 10.5 ± 6.7° to 19.0 ± 4.9° at 24 months. Mean segmental lordosis in L5/S1 increased from 15.1 ± 7.4° to 23.2 ± 5.6°. Cage subsidence due to severe osteoporosis occurred in one case after 5 months, and hence there was no further follow-up. Fusion was confirmed in all other patients.

CONCLUSION

Anterior interbody fusion offers good stabilisation and restoration of lordosis in iatrogenic spondylolisthesis and avoids the well-known problems associated with reentering the spinal canal for revision fusions. In this group, ODI and VAS scores were improved.

Fusion and subsidence rate of stand alone anterior lumbar interbody fusion using PEEK cage with recombinant human bone morphogenetic protein-2

INTRODUCTION

Anterior lumbar interbody fusion (ALIF) is an established treatment for structural instability associated with symptomatic disk degeneration (SDD). Stand-alone ALIF offers many advantages, however, it may increase the risk of non-union. Recombinant human bone morphogenetic protein-2 (BMP-2) may enhance fusion rate but is associated with postoperative complication. The optimal dose of BMP-2 remains unclear. This study assessed the fusion and subsidence rates of stand-alone ALIF using the SynFix-LR interbody cage with 6 ml/level of BMP-2.

METHODS

Thirty-two ALIF procedures were performed by a single surgeon in 25 patients. Twenty-five procedures were performed for SDD without spondylolisthesis (SDD group) and seven procedures were performed for SDD with grade-I olisthesis (SDD-olisthesis group). Patients were followed-up for a mean of 17 ± 6 months.

RESULTS

Solid fusion was achieved in 29 cases (90.6 %) within 6 months postoperatively. Five cases of implant subsidence were observed (16 %). Four of these occurred in the SDD-olisthesis group and one occurred in the SDD group (57 % vs. 4 % respectively; p = 0.004). Three cases of subsidence failed to fuse and required revision. The body mass index of patients with olisthesis who developed subsidence was higher than those who did not develop subsidence (29 ± 2.6 vs. 22 ± 6.5 respectively; p = 0.04). No BMP-2 related complications occurred.

CONCLUSION

The overall fusion rate of stand-alone ALIF using the SynFix-LR system with BMP-2 was 90.6 %, comparable with other published series. No BMP-2 related complication occurred at a dose of 6 mg/level. Degenerative spondylolisthesis and obesity seemed to increase the rate of implant subsidence, and thus we believe that adding posterior fusion for these cases should be considered.

Access related complications in anterior lumbar surgery performed by spinal surgeons

PURPOSE

Anterior lumbar surgery is a common procedure for anterior lumbar interbody fusion (ALIF) and artificial disc replacement (ADR). Our aim was to study the exposure related complications for anterior lumbar spinal surgery performed by spinal surgeons.

METHODS

A retrospective review was performed for 304 consecutive patients who underwent anterior lumbar spinal surgery over 10 years (2001-2010) at our institution. Each patient's records were reviewed for patients' demographics, diagnosis, level(s) of surgery, procedure and complications related to access surgery. Patients undergoing anterior lumbar access for tumour resection, infection, trauma and revision surgeries were excluded.

RESULTS

All patients underwent an anterior paramedian retroperitoneal approach from the left side. The mean age of patients was 43 years (10-73; 197 males, 107 females). Indications for surgery were degenerative disc disease (DDD 255), degenerative spondylolisthesis (23), scoliosis (18), iatrogenic spondylolisthesis (5) and pseudoarthrosis (3). The procedures performed were single level surgery--L5/S1 (n = 147), L4/5 (n = 62), L3/4 (n = 7); two levels--L4/5 and L5/S1 (n = 74), L3/4 and L4/5 (n = 4); three levels--L3/4, L4/5, L5/S1 (n = 5); four levels--L2/3, L3/4, L4/5, L5/S1 (n = 5). The operative procedures were single level ADR (n = 131), a single level ALIF (n = 87) with or without posterior fusion, two levels ALIF (n = 54), two levels ADR (n = 14), a combination of ADR/ALIF (n = 10), three levels ALIF (n = 1), three levels ADR/ALIF/ALIF (n = 1), ADR/ADR/ALIF (n = 2), four levels ALIF (n = 1) and finally 3 patients underwent a four level ADR/ADR/ALIF/ALIF. The overall complication rate was 61/304 (20 %). This included major complications (6.2 %)--venous injury requiring suture repair (n = 14, 4.6 %) and arterial injury (n = 5 [1.6 %], 3 repaired, 2 thrombolysed). Minor complications (13.8 %) included venous injury managed without repair (n = 5, 1.6 %), infection (n = 13, 4.3 %), incidental peritoneal opening (n = 12, 3.9 %), leg oedema (n = 2, 0.6 %) and others (n = 10, 3.3 %). We had no cases of retrograde ejaculation.

CONCLUSION

We report a very thorough and critical review of our anterior lumbar access surgeries performed mostly for DDD and spondylolisthesis at L4/5 and L5/S1 levels. Vascular problems of any type (24/304, 7.8 %) were the most common complication during this approach. The incidence of major venous injury requiring repair was 14/304 (4.6 %) and arterial injury 5/304 (1.6 %). The requirement for a vascular surgeon with the vascular injury was 9/304 (3 %; 5 arterial injuries; 4 venous injuries). This also suggests that the majority of the major venous injuries were repaired by the spinal surgeon (10/14, 71 %). Our results are comparable to other studies and support the notion that anterior access surgery to the lumbar spine can be performed safely by spinal surgeons. With adequate training, spinal surgeons are capable of performing this approach without direct vascular support, but they should be available if required.

Limited access surgery for 360 degrees in-situ fusion in a dysraphic patient with high-grade spondylolisthesis

Progressive high-grade spondylolisthesis can lead to spinal imbalance. High-grade spondylolisthesis is often reduced and fused in unbalanced pelvises, whereas in-situ fusion is used more often in balanced patients. The surgical goal is to recreate or maintain sagittal balance but if anatomical reduction is necessary, the risk of nerval damage with nerve root disruption in worst cases is increased. Spinal dysraphism like spina bifida or tethered cord syndrome make it very difficult to achieve reduction and posterior fusion due to altered anatomy putting the focus on anterior column support. Intensive neural structure manipulation should be avoided to reduce neurological complications and re-tethering in these cases. A 26-year-old patient with a history of diastematomyelia, occult spina bifida and tethered cord syndrome presented with new onset of severe low back pain, and bilateral L5/S1 sciatica after a fall. The X-ray demonstrated a grade III spondylolisthesis with spina bifida and the MRI scan revealed bilateral severely narrowed exit foramina L5 due to the listhesis. Because she was well balanced sagittally, the decision for in-situ fusion was made to minimise the risk of neurological disturbance through reduction. Anterior fusion was favoured to minimise manipulation of the dysraphic neural structures. Fusion was achieved via isolated access to the L4/L5 disc space. A L5 transvertebral hollow modular anchorage (HMA) screw was passed into the sacrum from the L4/L5 disc space and interbody fusion of L4/L5 was performed with a cage. The construct was augmented with pedicle screw fixation L4-S1 via a less invasive bilateral muscle split for better anterior biomechanical support. The postoperative course was uneventful and fusion was CT confirmed at the 6-month follow-up. At the last follow-up, she worked full time, was completely pain free and not limited in her free-time activities. The simultaneous presence of high-grade spondylolisthesis and spinal dysraphism make it very difficult to find a decisive treatment plan because both posterior and anterior treatment strategies have advantages and disadvantages in these challenging cases. The described technique combines several surgical options to achieve 360° fusion with limited access, reducing the risk of neurological sequelae.