Minimally Invasive Surgery

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Minimally Invasive Spine

Surgery is the use of small incisions, meticulous tissue handling and the latest microscopic technologies to do operations that in the past would have required large incisions and extended recoveries.

This technology can be applied to:

  1. Lumbar decompressions
  2. Anterior cervical fusions
  3. Posterior cervical foraminotomies
  4. Some lumbar fusions

To illustrate a case in point the following was described on the SpineUniverse website:

SpineUniverse Case Report: Minimal Access Spinal Technologies (MAST) Fusion for Osteomyelitis


This 84 year old man was initially reviewed in September 2001 after having had a laminectomy performed by an outside institution for presumed spinal stenosis. He had had a poor outcome from the surgery in terms of hip and thigh pain and postoperative MR scanning at that time confirmed multiple lesions throughout the lumbosacral spine, which on CT-guided biopsy confirmed underlying metastatic prostate cancer. He was managed non-surgically with appropriate chemotherapy and radiotherapy.

This man presented in April 2003 with severe mechanical back pain, in the absence of neurological symptoms in his lower limbs and without bladder or bowel dysfunction. On examination he was noted to be somewhat cachetic, neurologically intact, with an elevated white cell count and ESR. His initial imaging is shown below:


(Above): Marked osteopenia is present. The L2/3 disc space is ill-defined and there appears to be a crush fracture in the L3 vertebral body.


(Above): T1-weighted sagittal MR scanning showing low signal change in the L3 body and lower portion of the L2 vertebral body. The L2/3 disc space is poorly defined. No epidural collection was identified on the imaging

Initially it was felt that the changes in the L3 body were due to metastatic prostate cancer. Because of the peridiscal changes however, a CT-guided aspiration biopsy of the disc space was effected and tissue taken for culture. Enterococcus was cultured from the disc space and appropriate antibiotic therapy was commenced. A preoperative DEXA scan gave a lumbar T score of -3.4.

After 2 weeks of antibiotic therapy, repeat MR scanning was unchanged and the patient still suffered from severe mechanical back pain resistant to bracing and relieve with bed rest. He again had no neurological symptoms in his lower limbs and was neurologically intact. It was felt that the loss of the posterior columns from his initial surgery had left him with a grossly unstable spine that may fuse over time with the smouldering disctis/osteomyelitis, however until that occurred he was at major risk of developing kyphosis, collapse and neurological compromise. Assessment by our medical and anaesthetic services deemed him unfit for a major reconstructive procedure to perform either an anterior or posterior vertebrectomy. In view of this, a minimally invasive procedure was offered in hopes of maintaining a posterior tension band whilst fusion of the anterior column occurred.


The patient was brought to the operating room and general anaesthesia was administered. After administration of intravenous antibiotic, the patient was placed into the prone position on the Jackson operating table. A digital fluoroscope was draped into the surgical field. A 2 cm incision was then made over the pedicle of L4 on the right. Using both AP and lateral films, the left L4 pedicle was then cannulated using and 11G bone biopsy needle (see below):


Under fluoroscopic guidance, guide wires were then placed into both the L2 and L4 vertebral bodies:


The L4 pedicle was then tapped and a 7.5 mm x 45 mm Sextant® (Medtronic-Sofamor Danek, Memphis, TN) screw was then placed. A 6.5 mm x 50 mm screw was then placed in the L2 pedicle (see below):

image010       image012

A rod was then passed through the heads of both screw using the Sextant® apparatus (see below):

image014      image016

The heads were secured and a similar procedure was performed on the left. The final construct is shown below:

image018    image020

The entire procedure was performed through 6 incisions 2 cm in length each (see below):


There were no problems intraoperatively and no appreciable blood loss. The patient was transferred to the ward uneventfully. Total operating time was 70 minutes.


The patient was well postoperatively and mobilized 48 hours after surgery in a brace. His mechanical pain had improved dramatically. His upright x-rays and CT scans at L2 and L4 are shown below and showed no adverse features:


image026     image028

He was discharged on oral antibiotics 2 weeks later. At last follow-up, 4 weeks after surgery, he remained pain free with no evidence of kyphosis on imaging.


Discitis and osteomyelitis leads to loss of structural strength of the vertebral body. With the loss of posterior elements from previous surgery gross instability can result. In patients who would not tolerate major spinal reconstruction, prolonged bedrest may be associated with significant morbidity and potential mortality. In this sort of scenario, being able to provide structural stability through a posterior tension band can lead to eventual fusion across the involved segments. This approach has been described before in the face of osteomyelitis, where pedicle screw fusion alone has lead to stability and eventual fusion.1 The application of minimally-invasive technology to this however is a new approach. By using MAST® techniques and the Sextant® apparatus, stabilization for osteomyelitis was effected in a patient who otherwise may not have been fit for any surgical endeavour.

The use of minimally-invasive approaches to spinal instrumentation is an exciting new technology that will allow surgery to be performed in patients who previously unfit for surgical intervention. Aside from degenerative disease, this case illustrates a novel approach to the stabilisation of the spine in the face of serious infection in a patient unfit for a major intervention.


  1. Karlsson MK, Hasserius R, Olerud C, Ohlin A: Posterior transpedicular stabilisation of the infected spine. Arch Orthop Trauma Surg 2002 Dec;122(9-10):522-57
  2. Case 2- Lumbar Endoscopy


This 55 year old man was referred to the surgeons at Dalcross Private Hospital and after having had 3 previous lumbar operations. The initial operation had been performed elsewhere for lumbar disc disease, at which time he suffered an inadvertent dural breach. Postoperatively, she developed a lumbar pseudomeningocoele and had 2 attempts elsewhere to try and close the leak. Their was currently no leakage of CSF from the wound. Unfortunately, he continued to have symptoms, and had postural symptoms of worsening back pain and pressure in the standing posture, relieved by lying down. His most recent preoperative MRI scan on referral is shown below (figure 2.1-2.2):

image17     image18

The MRI suggested a multiloculated CSF collection in the subfascial region of the lumbar wound. In view of the fact that he had had 2 previous attempts to repair the pseudomeningocoele, it was felt that a further open procedure would not be of great benefit. Symptomatically, the patient had a one-way valve effect with fluid draining from his thecal sac into his pseudomeningocoele, that was thought to be giving him the majority of his symptoms.


The patient was brought to the operating room and general anaesthesia was obtained. He was place in a prone position on the Andrews operating table. A rigid 6 mm 30( endoscope was then navigated into the pseudomeningocoele through a 1 cm paramedian lumbar incision. The pinhole connection between the dura and surrounding tissues was identified and this was enlarged with forceps and a 4F 5 ml Fogarty balloon (see figures 2.3-2.4 below).

Figure 2.3 and 2.4 (below): The 1 mm connection between the pseudomeningocoele and the thecal sac is identified. A magnified view is shown to the right. Neural structures are visible inside the dura.



Figure 2.5 (above): Post-fenestration myelogram confirming good retrograde flow of contrast material.

The procedure was uncomplicated and an on-table myelogram confirmed good retrograde flow between the pseudomeningocoele and the thecal sac (see figure 2.5).

Postoperatively, the patients recovery was unremarkable and he was well at last followup from her preoperative symptoms.


Cerebrospinal fluid leakage can complicated up to 10% of spinal surgical cases. Typically these are primary repaired and require no further intervention. Rarely, the leaks persist and patients may present with persistent CSF leakage from the wound, a subcutaneous swelling or a contained but symptomatic swelling. The initial treatment in typically aspiration and lumbar drainage or re-exploration. An epidural blood patch may also help. Occasionally this is unsuccessful. In the case, with 2 previous re-explorations, it was felt a minimally invasive procedure would avoid the pain and risks of another open procedure. Coupled with this, the internal architecture of the pseudomeningocoele was not disturbed, which allowed for easier identification of the flap valve.

Case 3: SpineUniverse Case Report: Minimal Access Spinal Technologies (MAST) Fusion for Trauma


This 86 year old man was admitted with a history of a fall in the absence of neurological deficit. He had significant comorbidities in terms of cardiac and respiratory disease. His initial imaging is shown below:


(Above): Preoperative T2-weighted MRI scan showing edema in the T12 vertebra is consistent with a recent fracture.


(Above): Sagittally reconstructed CT scans showing axial fractures in the T12 vertebrae extending through all 3 columns. The injury was consistent with a T12 undisplaced Chance fracture.


Because of his general health, the patient was not deemed fit for a major reconstructive procedure. Prolonged bedrest was also preferably avoided. In view of this he was offered percutaneous pedicle screw fusion via the MAST (Minimal Access Spinal Technology) technique using the Sextant® apparatus (Medtronic-Sofamor Danek, Memphis, TN).

The patient is shown below positioned in preparation for the surgery:


Using the sextant apparatus the T11 and then the L1 pedicles were sequentially cannulated with 5.5 x 45 mm screws. 4 screws were placed with 2 rods. The procedure was performed through a total of six 2 cm incisions. The Intraoperative imaging is shown below:


The incisions at the end of the case are shown as below:


There were no problems intraoperatively and no appreciable blood loss. The patient was transferred to the ward uneventfully. Total operating time was 75 minutes.

The patient was mobilized in TLSO with no adverse surgical complications.

4 weeks after surgery he was transferred to the rehabilitation service with no complications as a result of the stabilization. It would be envisioned that the instrumentation would be removed 12 months after surgery.


This case demonstrates the application of minimally-invasive spinal fusion technology to spinal trauma for the stabilization of a fracture that otherwise would have required a more extensive operation in a patient with significant comorbidities or for whom otherwise prolonged best and immobilization were the only options, with the risks of the known complications of these actions present as a result.

Chance fractures are classically described as occurring after motor vehicle accidents with seatbelt injuries. The fractures, if through the bony elements, if undisplaced, may be managed in a brace, but most surgeons would suggest some form of short segment fixation with early mobilization.(1,2)

This report described the application of MAST technology to facilitate spinal fusion for spinal trauma. In under 90 minutes, stabilization of an unstable fracture in a medically unwell patient was achieved. The use of this minimally-invasive technique offers home for the management of fractures in elderly patients as well as allowing for minimal blood loss and operative morbidity. Clearly, not all fractures are suitably managed through this technique but for those deemed medically inoperable or needed simple stabilization MAST fusion offers home of rapid mobilization with minimal risk.


  1. Louis CA, Gauthier VY, Louis RP: Posterior approach with Louis plates for fractures of the thoracolumbar and lumbar spine with and without neurologic deficits. Spine 23: 2030-2039, 1998
  2. Parker JW, Lane J, Karaikovic EE, et al: Successful short-segment instrumentation and fusion for thoracolumbar spine fractures. A Consecutive 4 ½ year series. Spine 25: 1157-1169, 2000