Spinal Endoscopy

Mark S. Gorchesky, M.D., DABPM
Mark S. Gorchesky, M.D., DABPM is with the Center for
Pain Management at University Medical Center, Jacksonville.

Chronic low back pain remains a difficult condition to diagnose and treat.^1,2 In 1992 Nachemson extensively reviewed the international literature on disabling low back pain.³ The United States experienced 20 million sick days per year with 2% of the work force being absent an average of nine days per year associated with low back pain. Germany, Canada, Great Britain, Netherlands and Sweden experienced proportionately greater sick days and abseentism.³ The Nuprin Pain Report (1986) conducted telephone interviews of 1,254 adult volunteers. Fifty-six percent of the respondents reported some back pain the preceding year.

Primary care physicians and specialists continue to search for definitive, cost effective diagnostic tools to establish such diagnoses. Spinal endoscopy allows direct visualization of the spinal canal, epidural space and it's related structures. The skilled endoscopist is capable of confirming some of the potential pain generators listed in Table 1, including epidural adhesions, nerve root edema, extrinsic and intrinsic compressions to the epidural space, anatomical variations, nerve root cystic lesions, mal-aligned spinal cord stimulators, and vascular abnormalities.

Historical Perspective

1931 - The first documented peer reviewed article on spinal canal endoscopy by Dr. Michael Burman.⁵ Eleven cadaver vertebral columns were examined using arthroscopic equipment (trochar with 3/8 inch), he concluded that myeloscopy was limited due to current technology but potential merit included visualization of the cauda equina for tumor or inflammation.⁵

1936 - Elias Stern, Department of Anatomy, Columbia University, described a spinascope and invisioned direct observation of posterior roots for rhizotomy in patients with intractable pain and sectioning of anterior roots for progressive spastic conditions.⁶

1937 - Dr. J. Lawrence Pool performed his first myeloscopic exam on an anesthetized subject. Late in 1942 he published experience with 400 cases, most performed with local anesthesia in the sitting position. His equipment was cumbersome but it allowed CSF sampling, manometric measurements and gas myelography through the myeloscope. Hand drawings and observations revealed normal anatomic relationships, epidural fat, neuritis of the filum terminilie and effects of a herniated nucleus pulposus or hypertrophied ligamentum flavum, arachnoid adhesions and unilateral neuroepithelioma of the cauda equina.^7-8

1943-1966 - No further reports in literature, potentially due to gaining acceptance of myelography and photographic technical difficulties of myeloscopy.⁹

1969-1978 - Ooi and colleagues developed an endoscope for intradural and extradural examinations. A fiber optic light source was used. Initial series of 86 patients were reported. Post dural puncture headache was reported in 70% of the patients temporarily. 208 procedures were performed refining the technique. Fiber optics were used only as a light source, not as a fiber optic myeloscope.^10-16

1981 - Ooi, et al report observations in changes in blood flow in the cauda equina during the Lasegue test. During the straight leg raising maneuver the author noted an anterior caudal displacement of the cauda equina and a cessation of blood flow. Valsalva, coughing or sneezing only resulted in a slight cephalad/caudad movement in the cauda equina. ¹⁷

1985 - Blomberg studied anatomic variations of the epidural space and it's contents including large amounts of fat and connective tissue. A dorsomedian band of connective tissue was observed compartmentalizing the epidural space. He concluded that the midline epidural approach was associated with increased bleeding complications and that a paramedian approach is likely to result in less complications.^18-20

1988-1991 - Smimoji, et al used smaller diameter flexible fiber scopes to visualize spinal canal disease (0.5, 0.9, 1.4 mm). The fiber scopes were introduced via a touhy needle in subarachnoid and epidural spaces. Some scopes were advanced to the level of the cisternae without patient discomfort. Slight headache and fever were observed post procedurally.^21-22

1991 - Saberski and Kitahata began evaluating various fiber optic systems. Questions regarding indications, technical images and maneuvering were addressed. A working channel for tissue sampling or injections was being investigated.⁹

1994 - Schultze, G, et al studied 12 patients with various pain syndromes observing ligamentum flavum, spinal dura matter, connective and adipose tissue, veins and arteries. Epidural catheters were safely placed under epiduroscopic control.²³

1995 - Saberski reported access to the epidural space via the sacral hiatus which allows direct three dimensional viewing of the epidural space and it's contents. Installation of Depo steroids were directly applied to pathologic nerve roots. Its usefulness was considered both diagnostic and therapeutic in various conditions such as nerve root irritation, adhesions, hematoma, abscess and tumor.^24-27

1998 - Saberski noted the importance of the epidural steroid treatment to reach the nerve root in question. The three dimensional capability of the myeloscope allows improved targeting of the injectate. Outcome studies are ongoing and better outcomes appear in patients with acute to subacute discogenic spinal pain syndromes. Some inflammatory mediators of discogenic pain are theorized to be "washed away" or diluted within the saline perfusion solution.^24-27

1998 - Uchiyama reported on a subarachnoid myeloscopic technique was performed and showed a fibernous mass pulsating on the spinal cord. No cysts or spinal cord herniation were identified at operation. Proposed pathologic features may represent a type of arachnoiditis with proliferation of fibrous tissue.²⁸

Potential Side Effects And Post Operative Complications

Hundreds of spinal endoscopies have been performed in historical literature alone. To date no serious post operative complication has been reported. The following is a list of some of the potential side effects and complications:

• Persistent pain at the sacral hiatus insertion site
• Paresthesia during procedure
• Drainage from the site of insertion
• Headache following the procedure
• Subcutaneous infection
• Subdural infection/abscess
• Arachnoiditis
• Meningitis
• Intracranial hemorrhage
• Retinal hemorrhage
• Increased pain
• Continued numbness, dysesthesia, paresthesia
• Paralysis
• Nerve root rupture or evulsion
• Dural puncture
• Post dural puncture headache

Skill, experience and strict regards for sterile technique are essentials to a successful outcome.

Technique

The patient is placed in the prone position. Strict sterile technique is used throughout the procedure. Local anesthesia is placed at the sacral cornu. A dilator/introducer system is placed in the caudal canal via a Seldinger guidewire technique. Fluoroscopy should be available for assistance.

A flexible 0.9 mm fiber optic endoscope is placed through and to the tip of a steerable video guided catheter. This catheter houses two working 1 mm channels. Saline solution is gently infused allowing distention of the epidural space. This now enables the endoscopist three dimensional color viewing of the spinal structures and multi-planar maneuverability to pathologic nerve roots encapsulated with adhesions. See Figures 1-10.

Figure 1. Video Guided Assembly A. Fiberoptic access port B. Guidewire/ Instrumentation access port C. Steering mechanism D. Flexible tip with 2 working 1 mm channels; fiberoptic scope ends here E. Injection port F. Injection port

Figures 2 - 10. Intraspinal Video Images

Summary

Physicians and scientists have explored the clinical usefulness of spinal endoscopy for over six decades. Utility of this technique continues to expand as technology advances. Improved imaging and maneuverability, tissue sampling and through scope instrumentation will be improvements available for the experienced endoscopist. Further investigation is recommended by skilled physicians of this demonstrably safe procedure.^24-26

ACKNOWLEDGEMENT : A special thank you to the Myelotec Corporation, Roswell, Georgia, for their permission to publish photographs pertaining to the endoscope and various epidural/intrathecal structures.

REFERENCES

1. Bonica JJ. The Management of Pain, Volume I, II, 2^nd Edition 1990.
2. Wibert E. Fordyce. Back Pain in the Workplace - IASP 1995.
3. Nachemson, AL; Newest Knowledge of Low Back Pain: A Critical Look", Clinical Orthopedics. 1992; 279 8-20.
4. Taylor H, et al. The Nuprin Pain Report. New York - Louis Harris and Associates, 1985.
5. Burman MS. Myeloscopy or the Direct Visualization of the Spinal Canal and its Contents, Journal of Bone and Joint Surgery, 13:695-696, 1931.
6. Stern EL. A Spinascope: Medical Record (NY). 1936; 143:31-32
7. Pool JL. Myeloscopy: Intraspinal Endoscopy. Surgery. 1942; II ( 2): 1942.
8. Pool JL, Bull. Direct Visualization of Dorsal Nerve Roots of Cauda Equina by Means of a Myeloscope. Archives of Neurology and Psychiatry. 1938; 39:1308-1312.
9. Saberski L. Evaluation of the Pain Patient. Chapter 13 - Spinal Endoscopy.
10. Ooi Y. Intrathecal Lumbar Endoscope. Clinical Orthopedic Surgery (Japanese). 1969; 4:295-297.
11. Ooi Y, et al. Myeloscopy. IGAKUNO AYUMI (Japanese). 1972; 81:209-212.
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13. Ooi Y, et al. Myeloscopy: Possibility of Observing Lumbar Intrathecal Space by Use of an Endoscope. Endoscopy. 1973; 5:91-96.
14. Ooi Y, et al. Myeloscopy: A Preliminary Report. Journal of the Japanese Orthopedics Association. 1973; 47:619-627.
15. Ooi Y, et al. Myeloscopy. INT Orthopedics. 1977; 1:107-111.
16. Ooi Y, et al. Myeloscopy. ACTA Orthopedics Belg. 1978; 44:881.
17. Ooi Y, et al. Myeloscopy with Special Reference to Blood Flow Changes in the Cauda Equina During Lasegue's Test. Internation Orthopedics. 1981; 4:307-311.
18. Blomberg R. A Method of Epiduroscopy and Spinoscopy: Presentation of Preliminary Results. ACTA Anesthesiology Scand. 1985; 21:113-116.
19. Blomberg R, et al. The Lumbar Epidural Space in Patients Examined with Epiduroscopy. Anesthesia and Analgesia. 1989; 68:158-160.
20. Blomberg R. Technical Advances of the Paramedian Approach of Lumbar Epidural Puncture and Catheter Introduction. Anesthesiology. 1988; 43:837-843.
21. Shimoji K, et al. Journal of Japan Society of Clinical Anesthesia. 1988; 8:215-220.
22. Shimoji K, et al. Observation of Spinal Canal and Cisternae with A Newly Developed Small Diameter Flexible Fiberscope.. Anesthesiology. 1991; 75:341-344.
23. Schultze G, et al. Direct Observation of the Epidural Space with a Flexible Catheter Secured Epiduroscopic Unit. Regional Anesthesia. 1994; 19 (2) 85-89.
24. Saberski L, et al. Direct Visualization of the Lumbar Sacral Epidural Space Through the Sacral Hiatus. Anesthesia Analgesia. 1995; 80:839-840.
25. Saberski L, et al. Chronic Pain Syndromes, Epidural Endoscopy, Section VI, Chapter 55/6, 1998.
26. Saberski L, et al. Survey Data: Outcome Spinal Canal Endoscopy - Paper presented at the Post Graduate Anesthesia meeting, New York, December 1998.
27. Saberski L, et al. ISIS Medical Media, Ltd., 1998.
28. Uchiyama S, et al. Ultrafine Flexible Spinal Endoscope and Discovery of an Unreported Subarachnoid Lesion. Spine. 1998; 23 (21) 2358-2362.

Jacksonville Medicine / April, 1999