referring to fig1 to 4 , a spinal implant in accordance with a first preferred embodiment of the invention comprises the following components as discussed in detail below . a body 10 has a substantially rectangular cross section and comprises a top surface 11 , a bottom surface 12 , and a peripheral surface 15 therebetween . the body 10 is formed of a composite material being sturdy and highly resistant to chemicals . the composite material may be carbon fiber or peek ( polyetheretherketone ). alternatively , the body 10 is formed of alloy such as stainless steel , cobalt - chromium - molybdenum alloy , titanium , or titanium alloy . still alternatively , the body 10 is formed of polymer such as uhmwpe ( ultra high molecular weight polyethylene ), pmma ( polymethylmethacrylate ), silicon rubber , or ultra high molecular polyethylene . still alternatively , the body 10 is formed of ceramic such as aluminum oxide , calcium phosphate tri - basic , or fiber glass . an upper retaining member 111 is formed on the top surface 11 and shaped as a plurality of rows of bone engaging projections ( i . e ., teeth ). a lower retaining member 121 is formed on the bottom surface 12 and shaped as a plurality of rows of bone engaging projections ( i . e ., teeth ). a three - dimensional matrix structure 14 is formed in the body 10 and on the peripheral surface 15 as support . the three - dimensional matrix structure 14 can provide mechanical properties such as enhanced resistance to pressure , enhanced resistance to stress , and enhanced resistance to tension to the body 10 . a plurality of holes 13 are formed through each of three directions of the three - dimensional matrix structure 14 . the holes 13 occupy about 1 % to 90 % of the volume of the body 10 depending upon engineering choice of design . each hole 13 has a bore of about 150 μm to 1 , 000 μm . as shown in fig4 specifically , a physician may insert the body 10 into a bore formed between an upper vertebra 21 and a lower vertebra 22 of a spine . the bone engaging projections of the upper retaining member 111 and the bone engaging projections of the lower retaining member 121 thus grasped the upper vertebra 21 and the lower vertebra 22 respectively ( i . e ., the body 10 being fastened ). moreover , an appropriate biocompatible material may filled in the voids of the holes 13 for stuffing and stabilization purposes . the biocompatible material may be calcium phosphate tri - basic ( cap ) or hydroxyapattie ( ha ) ( ca 10 ( po 4 ) 6 ( oh ) 2 ). the holes 13 allow body tissues to grow therein for the health of spinal bone . moreover , the fastening of the upper and lower vertebrae 21 , 22 and the upper and lower retaining members 111 , 112 is reliable so as to rigidly join the upper and lower vertebrae 21 , 22 . as a result , intervertebral stabilization is carried out . in addition , the provision of the three - dimensional matrix structure 14 can significantly increase resistance to pressure , stress , and tension to the body 10 . therefore , the body 10 is sturdy and a useful life of the spinal implant can be prolonged . referring to fig5 to 8 , a spinal implant in accordance with a second preferred embodiment of the invention is shown . the characteristics of the second preferred embodiment are substantially the same as that of the first preferred embodiment except the following : a longitudinal channel 16 of circular section is formed in a central portion of the body 10 and communicates with the holes 13 . after inserting the spinal implant between the upper and lower vertebrae 21 , 22 with the upper and lower vertebrae 21 , 22 and the upper and lower retaining members 111 , 112 being fastened together in a surgery , bone tissues 30 may grow to fill in the channel 16 . this has the benefits of carrying out intervertebral stabilization and increasing the probability of a satisfactory recovery of a patient . referring to fig9 , a spinal implant in accordance with a third preferred embodiment of the invention is shown . the characteristics of the third preferred embodiment are substantially the same as that of the second preferred embodiment except the following : the peripheral surface 15 has two relatively smooth opposite sides , an inner surface of the channel 16 has two opposite smooth portions substantially aligned with the two opposite sides of the peripheral surface 15 , and no holes 13 are formed along the direction of the opposite sides of the peripheral surface 15 . referring to fig1 , a spinal implant in accordance with a fourth preferred embodiment of the invention is shown . the characteristics of the fourth preferred embodiment are substantially the same as that of the second preferred embodiment except the following : the peripheral surface 15 has all of four sides being relatively smooth , the channel 16 has a relatively smooth inner surface , and no holes 13 being formed transversely ( i . e ., the body 10 having no transverse holes 13 ). while the invention has been described in terms of preferred embodiments , those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims .
a spinal implant in one embodiment includes an implant for insertion between two opposite spaced vertebrae of a spine , comprising a body having a substantially rectangular cross section and comprising a toothed top retaining member , a toothed bottom retaining member , and a peripheral surface ; a three - dimensional matrix structure formed in the body and on the peripheral surface as support ; and a plurality of holes formed through at least one of three directions of the three - dimensional matrix structure .