Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

Podsumowanie

The technique described in this article is well-suited to the Mini-ALIF procedure, allows for excellent exposure and decompression, and facilitates microscope-assisted manipulation.

Streszczenie

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

Wprowadzenie

Anterior lumbar interbody fusion (ALIF), a fusion procedure that takes an abdominal approach to the anterior lumbar spine, was first described by O'Brien in 1983¹. With the advantages of less bleeding, less muscle and nerve damage, and the ability to restore lumbar lordosis and reduce the impact on adjacent segmental degeneration better than posterior lumbar interbody fusion, ALIF is now widely used to treat lumbar spondylolisthesis, spinal deformities, lumbar spine infections, and degenerative lumbar disc disease^2,3. However, the procedure can also lead to complications such as vascular, nerve, and ureteral injuries; early vascular injuries are especially common, occurring in 10.4% of cases^4,5,6,7,8,9.

The use of a microscope during the procedure allows for a clearer operative field, resulting in greater safety in terms of reducing tissue damage, as well as smaller surgical incisions^8,10. However, minimally invasive anterior lumbar interbody fusion (Mini-ALIF) still requires a high degree of visualization and stability and requires the use of appropriate spreaders. Early framed laparoscopic spreaders, such as the Synframe system's Activ O spreader or the currently used Miaspas-ALIF spreader (Aesculap), are primarily used for conventional open ALIF surgery¹¹, but their poor microscopic stability, complex installation requirements, and high costs have hampered the use of microscopy in anterior lumbar spine surgery.

In this study, we introduce a new spreader system for microscope-assisted Mini-ALIF that involves opening the operative field and accomplishing nerve decompression under a microscope through a block and retractors fixed to the vertebral body. This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for Mini-ALIF. This system can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

Protokół

This study was reviewed and approved by the Hebei Medical University Third Affiliated Hospital ethics committee, and written informed consent was obtained from all the patients. In addition, no images are identifiable to any patients.

1. Preoperative preparation

1. Select appropriate cases based on the patient history, including symptoms, signs, history of previous lumbar and abdominal surgery, abdominal examination, and imaging, such as lumbar X-ray, computed tomography (CT), and magnetic resonance imaging (MRI).
2. Advise the patients to undergo preoperative CT angiography of the abdominal aorta and CT angiography of the inferior vena cava to rule out vascular malformations, as well as fasting and enemas the day before surgery for gastrointestinal preparation.

2. Surgical procedures

1. Figure 1 depicts the surgical procedure for Mini-ALIF. After general anesthesia, place the patient in the supine position with the hands either flat or on the chest to accommodate an intraoperative lateral X-ray.
   NOTE: If the abdominal wall and psoas major muscles are too tight, padding under the thighs is added, and the patients are maneuvered into the bladder stone position.
2. Locate the surgical lumbar segment by abdominal palpation of the iliac crest and the location of the Kirschner needle under X-ray.
3. Use a right side incision for the operation of the L5-S1 segment, and use a left approach for the rest of the segments. Use a scalpel to cut the skin and subcutaneous tissue in turn. Make a transverse incision in the lateral rectus abdominis muscle next to the lower abdomen, with a single segment length of ~5 cm. Use oblique or vertical incisions of about 8 cm in double-segment surgery.
4. Identify and incise the anterior rectus abdominis sheath with the aid of a microscope (with a working distance of 535 mm). Then, separate the rectus abdominis muscle bluntly to its outer edge, and retract the outer edge of the rectus abdominis toward the midline using a pulling hook to reveal the posterior rectus abdominis sheath.
5. Adjust the appropriate distance and magnification from the microscope to the operating area during the operation. Then, separate the anterolateral abdominal wall of the peritoneum with gauze balls under a microscope, and push contralaterally into the retroperitoneal space to reach the anterior aspect of the vertebral space.
6. Separate the prevertebral soft tissue bluntly with gauze and vascular forceps. Explore the sacral vascular space microscopically. Use vascular forceps and nerve strippers to separate the iliac arteriovenous vein. Furthermore, ligate the median sacral artery using silk thread depending on its occlusion.
   NOTE: Take care to avoid having to use electrocoagulation, which can damage the inferior ventral plexus.
7. Use the spreader to expose the surgical field in all directions. Fix the pulling hook to the vertebral body using a K-wires positioning tube on either side of the vertical section. Figure 2A shows the pull hook part of the spreader.
8. Figure 2B, C shows the second part of the spreader, which is designed as a combination of two draw-off tabs with a puller and a push-rod. Connect the retractor on one side to the straight-grip pull-rod to provide a pulling force on the soft tissue. The other retractor piece has three attachment holes at different depths; have the assistant attach these holes with a T-pusher on the opposite side to assist the surgeon in pushing away the soft tissue.
9. Then, use a 3.2 mm diameter positioning tube to secure the spreader to the two adjacent vertebral bodies of the operated segment using K-wires on either side of the retractor.
10. Expose the intervertebral space, and incise the disc annulus fibrosus. Remove the diseased disc, and then decompress the spinal canal guided by a microscope.
11. Scrape the endplate with an endplate rugine. Select anterior lumbar fusion apparatus of an appropriate size using a trial model. Fill autogenous bone fragments or bone mud and bone particles into the fusion apparatus and implant them into the surgical intervertebral space. Use an appropriate internal fixation according to the bone quality and diagnosis.

3. Post-surgery

1. Use 1 g of cefazolin sodium per 6 h to prevent infection for 24 h after the operation, and restrict the patient from eating until intestinal exsufflation.
2. After the patient gets out of bed the next day, advise them to gradually undergo rehabilitation training. Instruct the patient to wear a brace to walk and to use the waistline brace continuously for 3 months.

Wyniki

Patients who received Mini-ALIF for lumbar degenerative disease at Hebei Medical University Third Affiliated Hospital between July 2020 and August 2022 were enrolled retrospectively, and basic information such as age and gender, as well as medical records and imaging information, were recorded. The inclusion criteria were patients receiving Mini-ALIF for lumbar spinal stenosis, discogenic low back pain, and low-grade (I or II) slippage that had failed to respond to strictly conservative treatment for more than 6 months. ...

Dyskusje

Several turns surrounding the peritoneum during Mini-ALIF surgical exposure and decompression of the spinal canal are critical steps in the surgery. Injury to the anterior peritoneum when opening the anterior rectus abdominis sheath and separating the transverse abdominal fascia can easily lead to failure with this approach⁵. In addition, patients with lumbar spine infections and a history of abdominal surgery can develop intraoperative complications such as adhesions of the peritoneum and soft ti...

Materiały

Name	Company	Catalog Number	Comments
Anterior Lumbar Cage Instrument	LDR Medical	ROI-A
Cefazolin Sodium for Injection	Brilliant Pharmaceuticals	Chinese Drug Approval Number H20217016
Coagulation Forceps	Zhenjiang Hengsheng Juen Medical Instrument Co., Ltd.	BZN-Q-A-S
Coated, Braided Silk	Suzhou Jiasheng Medical Treatment Products Co.,Ltd.	2-0(4#)
Endplate Rugine	LDR Medical	IGO16R
Microscope	Carl Zeiss AG	S88
SPSS Statistics for Windows	IBM Corp	version 26.0
Surgical ablation electrodes	Jiangsu Yibo Leiming Medical Technology Co., Ltd.	LM-A5