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 Table of Contents  
Year : 2022  |  Volume : 19  |  Issue : 2  |  Page : 51-53


Department of Spine Surgery, Baby Memorial Hospital, Kozhikode, Kerala, India

Date of Submission11-Jan-2023
Date of Acceptance12-Jan-2023
Date of Web Publication09-Feb-2023

Correspondence Address:
Suresh S Pillai
Baby Memorial Hospital, Kozhikode, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/joasis.joasis_1_23

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How to cite this article:
Pillai SS. Keyhole?. J Orthop Assoc South Indian States 2022;19:51-3

How to cite this URL:
Pillai SS. Keyhole?. J Orthop Assoc South Indian States [serial online] 2022 [cited 2023 Mar 27];19:51-3. Available from: https://www.joasis.org/text.asp?2022/19/2/51/369400

  Introduction Top

Minimally invasive surgery implies minimal direct exposure of the spinal anatomy. Laparoscopy, thoracoscopy, and arthroscopy are done in cavities, after the cavity is inflated with gas or saline. However, preserving the abdominal wall muscles avoiding larger cuts on the chest wall and avoiding opening up of the joints reduces the morbidity very much. However, in difficult cases and when the situation demands, you cannot insist on continuing with keyhole surgery, even though the incidence is less. The spine being a solid organ, one cannot put pedicle screws in different vertebrae with single keyhole incision. One has to make an incision at each and every point where they wish to place the pedicle screw. When a tubular retractor is placed through the small muscles of the back which are attached to the spinous process and transverse process, how much is the stretch of the muscle, how much damage does it cause to the muscle?

Scarring occurs even when a tissue space is invaded, even with normal saline.

How much is the permissible blood loss during a procedure? How much blood one can donate safely without any health issues? How much is the recommendation?

How much radiation does the patient, the surgeon, and his team undergoes

Is it worth taking a risk? How long is the scar? Is it cosmetic?

Many similar questions need to be answered.

  Minimally Invasive Spine Surgeries Top

Minimally invasive spine (MIS) surgeries on the spine are those done with minimal direct exposure of the spinal anatomy. These surgeries should be performed with utmost care and vigilance due to the close proximity of the major neural and vascular structures.

The surgeons should have positional awareness throughout the surgery and rely mostly on two-dimensional fluoroscopy with C-arm or O-arm, image-guided techniques, specialized C-arms or O-arms, or robotics. The major disparity of spinal surgery with lap/thoraco/arthroscopic surgeries is that the spine is a solid organ while the others are different organs inside a cavity. These cavities are inflated with gas or saline. Then, the entry will be through small holes. However, in the spine, you have to put an incision where ever you want to put a pedicle screw. Imagine putting separate incisions on the abdomen where ever you want to approach an abdominal organ? In short, it is comparing mangoes and oranges.

Apart from a far lateral discectomy, most of the fusions and instrumentation on the spine require a separate incision. Of course, when you want to approach the spine anteriorly, you can use a laparoscopy, or thoracoscopy, even though the learning curve is a bit longer. This can be called keyhole surgeries.

  Aim of Discectomy Top

Surgical discectomy in the indicated case is a direct solution to the problem. However, people spend more time and money on alternative therapies. Nonrandomized and uncontrolled studies show favorable results for these procedures. A randomized control study shows no better than a placebo. None of their alternative methods are proven to be superior to surgical excision. The rate or degree of spontaneous resolution of a prolapsed disc is unpredictable.

A randomized double-blind study of epidural steroids versus epidural saline showed that epidural steroids are no more effective than saline.[1]

Indications for discectomy depend on the severity of pain, presence or progression of neurologic deficits, duration of symptoms, and trend of increasing or decreasing symptoms.

A delay in surgery is associated with less favorable outcomes.[2]

  Different Techniques of Discectomy Top


Microdiscectomy can be done through a small incision without compromising any supporting structures. The facet and posterior ligament complex are not compromised. The success rate in the ideal patient population is 90%.[3] It can be done under general anesthesia, local, spinal, or epidural anesthesia.[4] None of these anesthesia techniques has any benefits on the outcome of discectomy.[4]

Tubular discectomy

The site of discectomy is localized with C-arm. The data for the benefit of tubular discectomy compared to the standard procedure are conflicting.[5]

Microtubular discectomy

Microtubular discectomy has shown a 10% recurrence rate that warrants repeat surgery over a 10-year follow-up period.[6]

  Percutaneous Transforaminal Endoscopic Lumbar Discectomy Top

According to the literature, the recurrence rate after percutaneous transforaminal endoscopic lumbar discectomy (PELD) is 3%–10%. It is very useful for foraminal and extraforaminal disc herniations. When other types of discs are removed, injury to the superior articular facet is a known complication. Conversion to conventional technique due to a missed fragment is 3.5%–7.5% according to the literature. Other complications are dural tears, exiting nerve root injuries (1%–6.7%), seizure due to increased epidural fluid pressure, retrograde ejaculation, etc., Scarring after surgery is due to the destruction of epidural fat, epidural hematoma, invasion of the erector muscles of the spine to the defect, and destruction of annular fibrosis. The decisive stimulus for scar formation can be from invasion of a virgin space, even with saline can induce scar formation [Figure 1] and [Figure 2].
Figure 1: Surgical scar after conventional three-level fusion

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Figure 2: Surgical scar after single-level MIS fusion. MIS: Minimally invasive spine

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Sung et al. have shown centrally located high canal compromise (>50%), and nonmigrated disc has the highest recurrence rate (15% after PELD).[7]

In low-grade herniations and nonmigrated herniations, there is no significant difference according to Sung et al. They have concluded that open surgeries are considered for disc herniations with high canal compromise and high-grade migrations. PELD can be considered a surgical option in remaining intracanal herniations. The rate of operative failure following PELD differed according to the size and location of the herniation.[7] All recurrences cannot be addressed with PELD. In cases with severe stenosis, neurological deficit, calcified disc, and lateral recess stenosis, repeated conventional discectomy is better. PELD could be limited. In foot drop or cauda equina syndrome, an open re-exploration is mandatory.[8]

Another drawback of MIS surgeries is radiation exposure, especially when pedicle screws are placed. Radiation exposure has no threshold effect, and there is no dose of radiation below which the risk of excess tumor formation is 0. Moreover, the effect of radiation is cumulative over the course of a lifetime. It is shown that single radiation exposure above 100 mSv increases the risk of some cancers in humans.[9] It is also shown that orthopedic surgeons have five times increased chance of tumor development than other hospital workers. C-arm fluoroscopy for pedicle screw placement involves 10–12 times radiation exposure compared to nonspinal musculoskeletal procedures.[10] The patient gets above 43 mSv in a lumbar instrumented fusion with fluoroscopic assistance[11] (seven times annual effective dose). Hence, surgeons and assistants can use personal protective equipment (lead aprons, thyroid shields, Lead Goggles, etc.). However, the patient gets radiation.

Blood loss is another criterion looked at when conventional methods of spine surgeries and MIS surgeries are compared. We donate about 350 ml of blood without any harm.[12] When a surgery is done, the blood loss may better be kept at the minimum but within the permissible loss limits. Blood loss depends on patient factors, effect of anesthesia, surgical techniques, vascularity of the area, and the surgeons who do it (meticulously). Needs a double blind randomized Controlled Trial to neutralize the biases and know the advantages of minimal difference in blood loss during surgery.

  Conclusion Top

Surgical discectomy/instrumentation can be done with different methods. Choose the method depending on the expertise of the surgeon as well as the one best suited for the patient in a particular situation.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Gupta MC, Bridwell KH. Bridwall and Dewalds Textbook of Spinal Surgery. 4th ed. Vol. 1. Philadelphia: Wolters Kluwer; 2020.  Back to cited text no. 1
Peul WC, van Houwelingen HC, van den Hout WB, Brand R, Eekhof JA, Tans JT, et al. Surgery versus prolonged conservative treatment for sciatica. N Engl J Med 2007;356:2245-56.  Back to cited text no. 2
Rish BL. A critique of the surgical management of lumbar disc disease in a private neurosurgical practice. Spine (Phila Pa 1976) 1984;9:500-4.  Back to cited text no. 3
Morawetz RB, Murray RB. In: McCullough JA, Williams RW, Young TH, editors. Microsurgery of the Lumbar Spine. Rockwell, MD: Aspen Publications, Inc.; 1990. p. 271.  Back to cited text no. 4
Arts MP, Brand R, van den Akker ME, Koes BW, Bartels RH, Peul WC, et al. Tubular diskectomy versus conventional microdiskectomy for sciatica: A randomized controlled trial. JAMA 2009;302:149-58.  Back to cited text no. 5
Carragee EJ, Spinnickie AO, Alamin TF, Paragioudakis S. A prospective controlled study of limited versus subtotal posterior discectomy: Short-term outcomes in patients with herniated lumbar intervertebral discs and large posterior anular defect. Spine (Phila Pa 1976) 2006;31:653-7.  Back to cited text no. 6
Sung KH, Lee SH, Kim JS, Lee IM, Sung YS, Lee HY. Percutaneous endoscopic manual and laser discectomy for herniated lumbar discs. Technical digest CLEO/pacific Rim '99 pacific Rim Conference on lasers and electro-optics (Cat No99TH8464). Der Orthopade 1996;25;49-55.  Back to cited text no. 7
Ahn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY. Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: Surgical technique, outcome, and prognostic factors of 43 consecutive cases. Spine (Phila Pa 1976) 2004;29:E326-32.  Back to cited text no. 8
Brenner DJ, Doll R, Goodhead DT, Hall EJ, Land CE, Little JB, et al. Cancer risks attributable to low doses of ionizing radiation: Assessing what we really know. Proc Natl Acad Sci U S A 2003;100:13761-6.  Back to cited text no. 9
Kim CW, Lee YP, Taylor W, Oygar A, Kim WK. Use of navigation-assisted fluoroscopy to decrease radiation exposure during minimally invasive spine surgery. Spine J 2008;8:584-90.  Back to cited text no. 10
Jones DP, Robertson PA, Lunt B, Jackson SA. Radiation exposure during fluoroscopically assisted pedicle screw insertion in the lumbar spine. Spine (Phila Pa 1976) 2000;25:1538-41.  Back to cited text no. 11
Policies and guidelines National Blood Transfusion Council. Naco NBTC, Ministry of health and family welfare , Govt of India, 2021.  Back to cited text no. 12


  [Figure 1], [Figure 2]


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