Guest Editorial

VERSATILE MANMAN POWER SYSTEM

Dr. Abhijit JoshiOrthopedic SurgeonMb, D Ortho, Fellow (NUH) Singapore Pune.
dr.abhijit@gmail.com

Polytrauma patients present a very challenging situation, and I would like to share my experience of using Manman power systems. I have been using the Manman power drill since over a decade and I am and will always be a fan of the Manman power drill. Polytrauma patients often have multiple skeletal injuries along with a head injury and operating upon them is sometimes required as a life saving procedure. Manman power system remains one of the most important instruments required to undertake such an endeavor; for, without it, fracture fixation is now nearly impossible.


On one such occasion, I had the privilege of using the full arsenal of Manman power systems. A Polytrauma patient with multiple long bone fractures and an open fracture of the Tibia was presented along with an acute subdural compressive hematoma. After primary splinting and investigations, the patient was posted for Subdural hematoma decompression and fixation of the long bone fractures as well as debridement and fixation of the open fracture of the tibia. 

Here multiple functions of the Manman power drill were used to the fullest. Whilst the neurosurgeon used the cranial burr of the Manman power system and proceeded with his surgery at the head end, I was able to use the cordless drill to continue with the interlocking nail reaming of the long bones. First the universal Manman drill cable was used on the contralateral side to fix the Radius and Ulna. Since the same cable can be used for multiple hand drills, after the forearm bone fixation, only the hand piece was exchanged and fracture of the lower end of the radius was also fixed. With the high torque low RPM hand piece 'K' wires were percutaneously inserted. All this was done while using one cable and multiple hand pieces and a cordless drill for the Femur and Tibia nailing reaming and IL screw fixation.


Manman power systems are versatile and a reliable piece of equipment which is a necessity in every orthopaedic’s OT. I am pleased with their prompt after-sales service on any issue, if any, occurs.


  Thank you Team Manman for your continuous new innovations and for providing an economical power drilling solution.

******

POWER TOOLS IN ORTHOPAEDIC SURGERY-  AN UPDATE

Dr. Satish P Kale
Consultant Orthopedic Surgeon
MS (Orth.), FRCS(Edin.)
FRCS(Orthopaedics),
Diploma in Sports Medicine (U.K) 
bonejointdoc@yahoo.co.in


Power tools form the backbone of modern orthopaedic surgical procedures. Power tools have undergone many improvisations and modifications in the past two decades and have improved tremendously in their functionality and versatility. Though a natural extension of ordinary orthopaedic armamentarium, they have progressed to form the third arm and many a surgeon would be lost without these in their quiver. Orthopaedic cutting tools often receive little medical or even engineering attention beyond the considerations of size and shape. Medical power tools are unfortunately a replica of those used in the metal cutting industry and have evolved as “smaller powered version” of the same. The machining techniques and manufacturing technology deployed for these medical instrumentation are frequently modeled after these industrial designs. This 'off-the-shelf' information is then applied to the requirements of a particular orthopaedic application, saving time and allowing more efforts to be spent on improving implant performance. 

                       Optimum characteristics of cutting tools

1. Exhaust pathway for bone shavings and metal debris: Shavings produced by a fluted face-cutting tool have a very difficult flow path. Following the action of the instrument they must make a right angle turn, then follow a long and narrow channel before clearing the tool. Additional torque and thrust must be applied to maintain cutting action and to compensate for the power required to push the shavings outside the cavity. The heat produced as a by-product of this inefficiency can also cause thermal necrosis and delay bone healing. In contrast, a rotary plane has a short and direct flow path that doesn't create the problems described above. Torque, thrust and heat are reduced as a result with lesser damage to biology. 

2. Proper cutting edge geometry: Cutting edges intended for metal cutting must be very strong. The high tensile strength of metal requires a blunt angle at the cutting edge in order to resist the high forces generated during cutting. Since bone has a much lower tensile strength than typical metals, cutting edges intended for bone can have a much narrower angle and, as a result, will cut with less force and heat. 

3. Sharp, burr-free cutting edges. 

4.  Metallurgy: The tool’s ability to retain a sharp cutting edge hinges on various factors. Hardness is only one parameter. The other is, corrosion-resistance. A tool made from type 420 martensitic stainless steel hardened to Rc 52 holds an edge longer than a tool made from custom 455 precipitation hardening stainless steel at Rc 52. This is because the hardening mechanism for martensitic alloys produces very hard carbides that are dispersed throughout the material. Regardless of the alloy selected, cleaning and passivation should immediately follow finishing in order to maximize corrosion resistance. 

What other characteristics should we look for in selecting power tools?

* Power             * Simplicity     * Versatility
* Customized Performance       * Standardization

Core power tools in Orthopaedics are :

* Drill Systems    * Bone saws      * Burrs

Common power accessories used are :

* Power Pulse Lavage systems
* Cast cutters

Drill Systems

Drill systems are classified and selected on the basis of use in small/large bone surgery and based on specific applications like orthopaedics, neurosurgery or maxillo-facial applications. 
Various parameters considered are :

* Speed : available from 10,000 – 95,000 rpm
* Torque: Ideal is around 2.5 inches/oz.
* Debris channeling troughs: rotary plane type
* Size
* Weight
* Versatility and attachment combinations possible
* Reversibility of directions for drilling
* Heat profile
* Duty cycle
* Flexibility – Flexible or rigid
* Design of the instrument – ergonomics
* Throttled or throttle-less
* Teeth configuration – diamond tooth, serrated etc.
* Autoclavable options
* Low or high profile

Saws

Various characteristics determine saw selection. They are:

* Power Source: Pneumatic, Battery-operated or Electric
* Positions of blades possible
* Compatibility with different selections of blades
* Compatibility with other attachments
* Throttled or throttle-less
* Gear ratio: 5:1 is optimum

Various specifications available are:

Micro - sagittal saw: 0-25,000 cycles per minute (cpm)
* Throttle controlled
* 90-110 pounds per square inch (psi)
Micro- oscillating saw: 0-35,000 cpm
* Throttle controlled
* 90-110 psi
Micro- reciprocating saw: 0-22,000 cpm
* Throttle controlled
* 90-110 psi
Pneumatic extended oscillating saw: 0-35,000 cpm

Burrs

Burr functionality is determined by ball-tip design and configuration. Several designs are available depending on the procedure for which the burr may be required. 

Some configurations are:

* Barrel Tip Carbide
* Cross cut fissures
* End/Side cut carbide
* Lindemann Carbide
* Round cutting carbide
* Round diamonds
* Round end carbide
* Shannon 44, stainless

* Burr selection depends on application whether orthopaedic,         neurosurgical or maxillofacial.

                                                           **********


Engineering considerations for Fracture healing and fracture fixation with plating methods

Author : Dr. Ashok Desai
MS Ortho, Mumbai, MCH Orho UK

Total biological injury to the limb is combination of original trauma and surgical injury. Professor Sarmiento challenged a philosophy of stable fixation and immobilization of a joint above and below the fracture. He developed cast bracing for diaphyseal # in 1963.Cast bracing is a circumferential pressure of soft tissues. When axial load is applied, soft tissues behave like fluid and hold and stabilize the bones.

Histological studies of the cortical bone healing strongly suggest that the bone itself plays minimal role in the healing process. Surrounding soft tissues, primarily through capillary invasion are responsible for reparative process. However Professor Sarmiento agreed that surgical fixation is preferred when practical advantages of fixation over weighs the biological disadvantages. 
‘There is a race between fracture healing and fixation failure’.

Biomechanical Principles

The old dilemma of fixation, ‘how much rigid & how much flexible’ is explained on biological and biomechanical principles. 

Strain – Is the deformation at # site. 

Strain <2% - cortical bone heals with primary healing
Strain >2% & <10% - bone heals with secondary healing
Strain >10% - may lead to bone absorption
Amount of strain depends on length of # gap and stability of #

Stress on plate & screws:


The stress on the construct rises proportionately with increase in working length. If the plate is flexible then the stress is more on screw and plate. If the plate is rigid then the stress is less. If the distance between plate & bone is more, stability is less and the screw deformation increases.
The titanium plate is stronger than, the steel. Thinner plates are weaker and fixation is more flexible. Longer plate will increase axial stiffness and pullout strength, but torsional strength is not increased.
In comminuted # the length of the plate should be 3 times the # gap.
In simple # the length should be 8-10times the # gap.

Conventional plating:

The plating is done on tension side of the bone.  The screws should be inserted from periphery towards the #, if a plate is used in neutral mode.
In this the stability of fixation depends on friction between plate & bone. This is achieved by axial compression between head of the screw & purchase of screw in the bone.
Quality of bone will also determine the stability, which is best achieved by tapped cortical screw of appropriate size. It is recommended to have 3 bi-cortical screws on either side for axial stability and 4 screws for torsional stability (Humerus & Radius)

Biological (Bridge) plating:

The construct is more flexible and has higher stress at plate and screw. It produce 10-30% strain at # site, there fore it is used in cancellous metaphyseal area #. It causes less biological injury.

Locking plate:

The angular & axial stability is achieved via threaded interphase. Axial load is more on screw – bone junction, therefore larger core diameter of the screw is required. It is mandatory to use thinner threads to minimize bone loading in order to reduce bone destruction at screw-bone interphase.

Hybrid fixation:


This requires a plate with combo holes. It is mandatory to use cortex screws for reduction and compression and later on locking screws are added. Hybrid fixation does not reduce torsional stiffness.

Plating in Osteoporotic bones



The force required to move the screw= resistance of the bone x contact area.

To improve the purchase of screws, use a locking plate with multi-directional screws. Use cancellous screws. If bone is practically void inject bone cement.




Summary: The stability of fracture should be achieved at each step in a sequential manner. Splints, casts, external fixators, bridge plates, intramedullary rods lead to secondary healing. In plating methods one has to balance the amount of rigidity & flexibility. Excessive rigidity will lead to stress shielding and result in bone absorption. Excessive flexibility may lead to excessive strain at # site, which may result in delayed/non union. This may lead to failure of construct.


Some tips while Reaming with Flexible Reamers

Dr. B. Shivashankar, M.S. Ortho                                                       
Iyer Orthopaedic Centre
103, Railway Lines
SOLAPUR 413001


1.The flexible reamers from Manman are available from 6 mm to 8 mm in fixed heads (mainly used for Humerus Reaming) and with Detachable heads from 8.5 mm onwards upto 15 mm.

2. There are two separate shafts for reaming with detachable drill bits. The first one can be used upto 12 mm and the next shaft for reaming beyond 12.5 mm. This second shaft has  thickness and strength more than the regular shaft used for reaming upto 12 mm..

3. If one tries to use the thinner shaft for larger drill bits say 12.5 or 13mm, these drill bits will come off from the tip as they do not fit properly with the Omega shaped  slot in the drill bit. 

4. The control for the reamer should be always with the surgeon and not with the  assistant. So one can ream and stop as per the feel of the bone. And can stop reaming in emergency. Fig 1 and 2. 
Fig 1                                                                                             Fig 2


Fig. 1 Wrong way of using foot switch. Being operated by theatre staff and not by surgeon.
Fig 2. Wrong way of using foot switch. Being operated by theatre staff and not by surgeon.

 5. It will be some times better to extend the wire length of the foot switch. If one uses the foot switch control. 

6. The cable shaft which connects the motor to the hand piece, should not get wound or twisted while reaming. The best way will be to keep the motor behind the prepared instrument trolley table and support the cable with hand or instrument trolley while reaming.

7.If using a hand reamer, always lock the reamer switch for forward or clock wise rotation. If any inadvertent reverse movements happens, these reamer shafts will get unwound and they will get permanently damaged and requires replacement. Fig  5. 
Fig. 5 Showing the damaged reamer shaft. Note the twisting and also unwinding of the shaft due to forward and reverse  reaming usage of the reamer.

8. Never reverse the reaming while withdrawing the shaft backwards. Please remember that reaming is done clockwise both while pushing the reamer in and pulling out the reamer out. By this way, due to the direction of the flutes in the reamer head, the reamed material comes out backwards out of the medullary canal for effective reaming, otherwise the material left behind may cause unnecessary resistance for further reaming. This applies even for hand reaming with Kuntsher’s reamers.

9. Always ream over beaded guide wire. Though the fixed head reamers can be used over plain guide wire, but it is better always to practice to ream over a beaded guide wire as by chance the reamer breaks, one can take out the broken reamer piece. Fig 6 to 13 
Fig. 6                                                          Fig. 7

Fig. 8                                                          Fig. 9

Fig. 10                                                       Fig. 11
  
Fig. 12                                                       Fig. 13
                                             
10. Never jump numbers while reaming. One should always ream sequentially from the smallest reamer which can be passed easily. Fig 3 
Fig. 3


Fig. 3  C Arm  IITV picture showing stuck up 11mm drill bit and twisted reamer shaft due to skipping of reaming with earlier size.




11. Always ream in increments of 0.5 mm. This way you can ream the canal easily and also the chances of the reamer getting stuck will be less. This will help in preventing sudden too much stress on one larger reamer, chances of reamer head getting stuck will be also less and one can easily ream the canal. The heat generated at the tip of the reamer in turn bone necrosis secondary to reaming can be lessened. By this way the  reamer heads will remain sharp for longer duration.

12. Once we get some little resistance for reaming, always ream in small bursts. Like ream – stop- ream –stop- ream. This will also help in lessening the heat generated due to reaming.

13. Once more resistance is got while reaming, it is advisable to use the same reamer head and ream to and forth few times, especially the last one or two reamer sizes just before the nail insertion. Please remember  to take off the bone dust from the reamer head flutes every time you pass the same reamer. This will make the canal more uniform.




Lengthening and Deformity Correction with IM Nailing

Dr. Milind Choudhari
MS Ortho., Akola
milind .chaudhary@gmail.com     


  Lengthening and Deformity correction using minimally invasive Intramedullary nailing is a new advance which permits complete and accurate correction of deformities according to modern principles with great patient comfort.




  This surgery employs an entirely new paradigm, newer methods of thinking, planning and operative technique and new instrumentation. It also permits adherence to all the principles and rules of modern deformity correction.

Special Instrumentation includes

1) Straight Nails of all diameters and lengths with extra holes machined as per the need. 

2) Special instruments to achieve proper entry point and track of the nail in the proximal fragment. These are crucial for accuracy of correction.

3) Straight, Rigid, motorized reamers for converting a curved marrow canal into a straight one.


4)Poller screws help in limiting the path of the nail for deformity correction and for adding stability.


 Planning


     Requires taking full length AP and LAT or full segment x-rays with a circular magnification marker to get accurate measurements of length and diameter. Tracings can be made on a butter paper and the exact angle of entry of the IM nail, the exact location of the corrective and compensatory osteotomies are marked. 

Surgery

         In a femur with Valgus (distal) and Procurvatum (proximal) deformities, a straight IM nail is inserted through the intercondylar distal portal. Preliminarily, a LRS fixator with 2 pins is inserted away from the proposed track of the nail. A guide wire is inserted angled towards medial cortex at an angle of 81°. Starting instruments create an accurate track over the GW. Poller screws are inserted on either side to restrict the track for the nail. The corrective osteotomy is done apex of valgus. Nail is inserted till osteotomy and Ex-fix helps in achieving correction of valgus deformity with lateral displacement of the distal lateral cortex.  

       The LAT X-ray reveals the apex of the procurvatum deformity more proximally. The distance between the two osteotomies is marked and extra holes made in the nail per-operatively to lock the osteotomy. Straight rigid reamers create the proper track through the middle and proximal fragments. Proximal osteotomy is made percutaneously and nail is passed proximal to it. Distal locking of nail (in proximal femur) is performed if only deformity correction is needed. Ex-fix is removed on table greatly enhancing patient comfort with early restoration of joint movements.

             If lengthening also needed, the Ex-fix is retained till lengthening is achieved (through proximal osteotomy). When length is achieved, the nail is locked proximally and Ex-Fix is removed. 








Postero-Lateral (Percutaneous) Endoscopic Lumbar Discectomy (PELD) & Foraminoplasty (PELF)


   For many years medical science has tried dealing with the issues of lumbar disc herniation in the least invasive manner. PELD and PELF are the techniques which have not only made these intervention minimally invasive, but have added a new dimension to the philosophy of treating Sciatica and Neurogenic claudication.



    To briefly recapitulate the procedure, under local (or general) anesthesia, a long needle is introduced 10 to 12 cm lateral to midline aiming towards entering the desired disc at the intervertebral foramen level. This is done under continuous biplanar fluoroscopic control. After passing a guide wire, a dilator and working sheath are serially introduced using the Seldinger technique. A spinal endoscope of 20 to 30 degrees angulation is then passed with continuous irrigation. The nerve roots (exiting and transiting) are directly visualized. The offending disc fragment is then shrunk using radio-frequency waves and then removed mechanically with microscopic shaver. Laser can also be used to vaporize the herniated disc under direct vision. Endoscopic drills are used to remove the under-surface of the facet joint and clear the osteophytes. The lateral and foraminal part of the ligamentum  flavum  is removed with  endoscopic  punches and roungers. The disc fragment which is central or centro-lateral can also be removed by placing the endoscope at the perfect angle. The undersurface of the decompressed and pulsating thecal sac can be visualized to confirm the decompression. Bleeding is controlled by trigger-flex radio frequency apparatus. 

   After the procedure is over, the small opening in the skin is closed simply by taping it. So this virtually becomes stitchless surgery. If the disc prolapse is causing bilateral root compression, this procedure can also be done bilaterally  (simultaneously).

The obvious advantages of PELD and PELF are :

1.    Stitchless Surgery

2.  Completely new approach. Does not disturb the important paraspinal muscles, spinal bones and ligamentum flavum. No retraction of thecal sac and nerve roots is required.

3.  Preservation of ligamentum flavum maintaining the sanctity of the sac and epidural space. Prevents post operative epidural scarring.

4. Foraminal Stenosis due to disc, osteophytes and the ligamentum can only be addressed directly by this procedure. (This is impossible by routine posterior approach unless the facet joint is removed partly or completely). 

5.  Early (immediate) mobilization and resumption of duties is possible.






One has to Remember 



 a)  PELD and PELF procedures are extremely useful if the patient selection is perfect.

b) Conventional (Posterior) Endoscopic Spine Surgery does not have all the advantages of PELD and PELF (One should remember to differentiate the two)

c)  PELD and PELF are conceptually not very new, but due to the advancement in instrumentation, they have become super effective and are proven so by experience in the last four to five years.

d)  They have to be viewed as one of the many modalities useful for treatment of Spinal Problems.

      Before concluding I would like to thank our Endoscopic Spine Surgery team which has made this work possible. I would also like to thank Sigmund Opferkuch, my counterpart of our Indo-German Foundation for helping us start this branch.








    

















      























                      Skin Avulsion Flaps

                           - Dr. Anand Kelkar
                             M.S (Ortho)
                                                           

                 Skin avulsion flaps are more frequent today because of RTA. If not associated with complicated major injuries, they are left to the resident to be managed.

    Management of these flaps is dicey because many times it leads to necrosis which we attribute to severity of trauma. However there is an iatrogenic contribution to it.

  Principles of Management 

           - Minimal debridement should be done. We can repeat debridement but cannot retrieve original skin lost to aggressive debridement.
   - Debridement is preferably done without anesthesia because the patient does not allow you to remove surviving tissue on account of pain .
  - Do not try and mobilize the flap to complete cover the gap as it further compromises its blood supply .
    - Never try to suture the flap under tension in single attempt to cover the defect completely. This produces clotting of vessels leading to necrosis.
  Few loose sutures are ideal. This prevents collection of blood/serum under the flap. Cover the remaining raw  area  with  sofratules.    
 - Gentle compression dressing and immobilization help healing.
  - Flaps of sole are very important as an anesthetic flap leads to repeated ulcers in insensitive foot like Diabetic/Leprosy foot etc.
  Temptation for multiple mattress sutures with meticulous closure of the defect  must be avoided.
 - As it gives immense pleasure to the surgeon at the end of the procedure but ultimately flap gets necrosed.





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